Single-base editing in IGF2 improves meat production and intramuscular fat deposition in Liang Guang Small Spotted pigs

Background Chinese indigenous pigs are popular with consumers for their juiciness,flavour and meat quality,but they have lower meat production.Insulin-like growth factor 2(IGF2) is a maternally imprinted growth factor that promotes skeletal muscle growth by regulating cell proliferation and differentiation.A single nucleotide polymorphism(SNP) within intron 3 of porcine IGF2 disrupts a binding site for the repressor,zinc finger BED-type containing 6(ZBED6),leading to up-regulation of IGF2 and causing major effects on muscle growth,heart size,and backfat thickness.This favorable mutation is common in Western commercial pig populations,but absent in most Chinese indigenous pig breeds.To improve meat production of Chinese indigenous pigs,we used cytosine base editor 3(CBE3)to introduce IGF2 intron3-C3071T mutation into porcine embryonic fibroblasts(PEFs) isolated from a male Liang Guang Small Spotted pig(LGSS),and single-cell clones harboring the desired mutation were selected for somatic cell nuclear transfer(SCNT) to generate the founder line of IGF2^(T/T) pigs.Results We found the heterozygous progeny IGF2^(C/T) pigs exhibited enhanced expression of IGF2,increased lean meat by 18%-36%,enlarged loin muscle area by 3%-17%,improved intramuscular fat(IMF) content by 18%-39%,marbling score by 0.75-1,meat color score by 0.53-1.25,and reduced backfat thickness by 5%-16%.The enhanced accumulation of intramuscular fat in IGF2^(C/T) pigs was identified to be regulated by the PI3K-AKT/AMPK pathway,which activated SREBP1 to promote adipogenesis.Conclusions We demonstrated the introduction of IGF2-intron3-C3071T in Chinese LGSS can improve both meat production and quality,and first identified the regulation of IMF deposition by IGF2 through SREBP1 via the PI3KAKT/AMPK signaling pathways.Our study provides a further understanding of the biological functions of IGF2and an example for improving porcine economic traits through precise base editing.

Identification of porcine fast/slow myogenic exosomes and their regulatory effects on lipid accumulation in intramuscular adipocytes

Background Pork quality is affected by the type of muscle fibers, which is closely related to meat color, tenderness and juiciness. Exosomes are tiny vesicles with a diameter of approximately 30–150 nm that are secreted by cells and taken up by recipient cells to mediate communication. Exosome-mediated muscle-fat tissue crosstalk is a newly discovered mechanism that may have an important effect on intramuscular fat deposition and with that on meat quality. Various of adipose tissue-derived exosomes have been discovered and identified, but the identification and function of muscle exosomes, especially porcine fast/slow myotube exosomes, remain unclear. Here, we first isolated and identified exosomes secreted from porcine extensor digitorum longus(EDL) and soleus(SOL), which represent fast and slow muscle, respectively, and further explored their effects on lipid accumulation in longissimus dorsi adipocytes.Results Porcine SOL-derived exosomes(SOL-EXO) and EDL-derived exosomes(EDL-EXO) were first identified and their average particle sizes were approximately 84 nm with double-membrane disc-shapes as observed via transmission electron microscopy and scanning electron microscopy. Moreover, the intramuscular fat content of the SOL was greater than that of the EDL at 180 days of age, because SOL intramuscular adipocytes had a stronger lipid-accumulating capacity than those of the EDL. Raman spectral analysis revealed that SOL-EXO protein content was much greater than that of EDL-EXO. Proteomic sequencing identified 72 proteins that were significantly differentially expressed between SOL-EXO and EDL-EXO, 31 of which were downregulated and 41 of which were upregulated in SOL-EXO.Conclusions Our findings suggest that muscle-fat tissue interactions occur partly via SOL-EXO promoting adipogenic activity of intramuscular adipocytes.

RNA-seq analysis reveals the critical role of the novel lnc RNA BIANCR in intramuscular adipogenesis through the ERK1/2 signaling pathway

Background Long non-coding RNAs(lncRNAs)regulate numerous biological processes,including adipogenesis.Research on adipogenesis will assist in the treatment of human metabolic diseases and improve meat quality in livestock,such as the content of intramuscular fat(IMF).However,the significance of lncRNAs in intramuscular adipogenesis remains unclear.This research aimed to reveal the lncRNAs transcriptomic profiles in the process of bovine intramuscular adipogenesis and to identify the lncRNAs involved in the adipogenesis of bovine intramuscular adipocytes.Results In this research,a landscape of lncRNAs was identified with RNA-seq in bovine intramuscular adipocytes at four adipogenesis stages(0 d,3 d,6 d,and 9 d after differentiation).A total of 7035 lncRNAs were detected,including 3396 novel lncRNAs.Based on the results of differential analysis,co-expression analysis,and functional prediction,we focused on the bovine intramuscular adipogenesis-associated long non-coding RNA(BIANCR),a novel lncRNA that may have an important regulatory function.The knockdown of BIANCR inhibited proliferation and promoted apoptosis of intramuscular preadipocytes.Moreover,BIANCR knockdown inhibited intramuscular adipogenesis by regulating the ERK1/2 signaling pathway.Conclusion This study obtained the landscape of lncRNAs during adipogenesis in bovine intramuscular adipocytes.BIANCR plays a crucial role in adipogenesis through the ERK1/2 signaling pathway.The results are noteworthy for improving beef meat quality,molecular breeding,and metabolic disease research.

TIMP2 promotes intramuscular fat deposition by regulating the extracellular matrix in chicken

The interaction between myocytes and intramuscular adipocytes is a hot scientific topic. Using a co-culture system, this study aims to investigate the regulation of intramuscular fat deposition in chicken muscle tissue through the interaction between myocyte and adipocyte and identify important intermediary regulatory factors. Our proteomics data showed that the protein expression of tissue inhibitor of metalloproteinases 2(TIMP2) increased significantly in the culture medium of the co-culture system, and the content of lipid droplets was more in the co-culture intramuscular adipocytes. In addition, TIMP2 was significantly upregulated(P<0.01) in muscle tissue of individuals with high intramuscular fat content.Weighted gene co-expression network analysis revealed that TIMP2 was mainly involved in the extracellular matrix receptor interaction signaling pathway and its expression was significantly correlated with triglyceride, intramuscular fat,C14:0, C14:1, C16:0, C16:1, and C18:1n9C levels. Additionally, TIMP2 was co-expressed with various representative genes related to lipid metabolism(such as ADIPOQ, SCD, ELOVL5, ELOVL7, and LPL), as well as certain genes involved in extracellular matrix receptor interaction(such as COL1A2, COL4A2, COL5A1, COL6A1, and COL6A3), which are also significantly upregulated(P<0.05 or P<0.01) in muscle tissue of individuals with high intramuscular fat content.Our findings reveal that TIMP2 promotes intramuscular fat deposition in muscle tissue through the extracellular matrix receptor interaction signaling pathway.

Recurrent intramuscular lipoma at extensor pollicis brevis:A case report

BACKGROUND This report describes and discusses recurrent intramuscular lipoma(IML)of the extensor pollicis brevis(EPB).An IML usually occurs in a large muscle of the limb or torso.Recurrence of IML is rare.Recurrent IMLs,especially those with unclear boundaries,necessitate complete excision.Several cases of IML in the hand have been reported.However,recurrent IML appearing along the muscle and tendon of EPB on wrist and forearm has not been reported yet.CASE SUMMARY In this report,the authors describe clinical and histopathological features of recurrent IML at EPB.A 42-year-old Asian woman presented with a slowgrowing lump in her right forearm and wrist area six months ago.The patient had a history of surgery for a lipoma of the right forearm one year ago with a scar of 6cm on the right forearm.magnetic resonance imaging confirmed that the lipomatous mass,which had attenuation similar to subcutaneous fat,had invaded the muscle layer of EPB.Excision and biopsy were performed under general anesthesia.On histological examination,it was identified as an IML showing mature adipocytes and skeletal muscle fibers.Therefore,surgery was terminated without further resection.No recurrence occurred during a follow-up of five years after surgery.CONCLUSION Recurrent IML in the wrist must be examined to differentiate it from sarcoma.Damage to surrounding tissues should be minimized during excision.

Treatment of talipes equinovarus after triceps surae intramuscular hemangioma surgery by Ilizarov technology in adults:A case report

BACKGROUND Postoperative complications of triceps surae intramuscular hemangioma surgery with talipes equinovarus have rarely been described,and the evidence for treatment is limited.The purpose of this case study was to report the new application of the Ilizarov technique,which successfully treated talipes equinovarus in adults after triceps surae intramuscular hemangioma.CASE SUMMARY A 29-year-old woman treated with the Ilizarov technique for talipes equinovarus in the right leg after triceps surae intramuscular hemangioma surgery.The equinus deformity was roughly corrected after 2 years of follow-up,without significant secondary sequelae.CONCLUSION Talipes equinovarus caused by postoperative sequelae of intramuscular hemangioma was successfully corrected by the Ilizarov technique.The Ilizarov technique may be used for treating talipes equinovarus caused by various causes.

Intramuscular vaccine administrations including the adoption of"Zeta-track technique"&"without aspiration slow injection technique"(ZTT&WASiT):a prospective review

Objective:To review the current literature on the practice of intramuscular injections(IMIs),focusing on immunizations.Methods:The present study comprises 2 reviews,characterized by high-quality evidence,per taining to the deployment of the slow injection technique without aspiration(referred to in this paper as the without-aspiration slow injection technique[WASi T])and combined with the Zeta-track technique(ZTT).The literature review is oriented toward the analysis of 2 features associated with IMIs techniques:safety and pain,integrating new evidence on vaccinee positioning for each muscle site and general relaxation techniques in the multi-parametric analysis.Results:The rigorous and in-depth reviews in the current study reveal the usefulness of including,among the international guidelines for via intramuscular immunizations,the adoption of WASi T only for compliant vaccinees,and in combination with all validated techniques for IMIs,and the use of ZTT limitedly if specific well-developed muscles are indicated.All the technique's limitations are exposed.Conclusions:Future research directions are presented by including the author's study designs to provide indirect evidence for the validity of the rationale of the slow injection technique using scientific methods,and for the conduction of future randomized controlled trials(RCTs)focused on revisiting the adoption of ZTT in a dynamic and integrated immunizations protocol in anterolateral thigh(ALT),ventrogluteal(VG),and also in the deltoid muscle,in the specific cases analyzed.

Quantification of intermuscular and intramuscular adipose tissue using magnetic resonance imaging after neurodegenerative disorders

Ectopic adiposity has gained considerable attention because of its tight association with metabolic and cardiovascular health in persons with spinal cord injury（SCI）. Ectopic adiposity is characterized by the storage of adipose tissue in non-subcutaneous sites. Magnetic resonance imaging（MRI） has proven to be an effective tool in quantifying ectopic adiposity and provides the opportunity to measure different adipose depots including intermuscular adipose tissue（IMAT） and intramuscular adipose tissue（Intra MAT） or intramuscular fat（IMF）. It is highly important to distinguish and clearly define these compartments, because controversy still exists on how to accurately quantify these adipose depots. Investigators have relied on separating muscle from fat pixels based on their characteristic signal intensities. A common technique is plotting a threshold histogram that clearly separates between muscle and fat peaks. The cut-offs to separate between muscle and fat peaks are still not clearly defined and different cut-offs have been identified. This review will outline and compare the Midpoint and Otsu techniques, two methods used to determine the threshold between muscle and fat pixels on T1 weighted MRI. The process of water/fat segmentation using the Dixon method will also be outlined. We are hopeful that this review will trigger more research towards accurately quantifying ectopic adiposity due to its high relevance to cardiometabolic health after SCI.

Linoleic acid metabolic pathway allows for an efficient increase of intramuscular fat content in pigs

Background: Intramuscular fat(IMF) content is a relevant trait for high-quality meat products such as dry-cured ham,but increasing IMF has the undesirable correlated effect of decreasing lean growth.Thus,there is a need to find selection criteria for IMF independent from lean growth.In pigs,the proportion of linoleic(C18:2) and arachidonic(C20:4) acids decline with fat deposition and therefore they can be considered as indicators of fatness.The aim of this research was to estimate the genetic variation for C18:2 and C20:4 in IMF and their genetic correlations with IMF and lean growth traits,with the objective to assess their potential as specific biomarkers of IMF.The analysis was conducted using a full-pedigreed Duroc resource line with 91,448 records of body weight and backfat thickness(BT) at 180 days of age and 1371 records of fatty acid composition in the muscle gluteus medius.Results: The heritability estimates for C18:2 and C20:4 in IMF,whether expressed in absolute(mg/g of muscle) or in relative(mg/g of fatty acid) terms,as well as for their ratio(C20:4/C18:2),were high(> 0.40),revealing that the C18:2 to C20:4 pathway is subjected to substantial genetic influence.Litter effects were not negligible,with values ranging from8% to 15% of the phenotypic variance.The genetic correlations of C18:2 and C20:4 with IMF and BT were negative(-0.75 to-0.66,for IMF,and-0.64 to-0.36,for BT),if expressed in relative values,but almost null(-0.04 to 0.07),if expressed in absolute values,except for C18:2 with IMF,which was highly positive(0.88).The ratio of C20:4 to C18:2 also displayed a stronger genetic correlation with IMF(-0.59) than with BT(-0.10).Conclusions: The amount of C18:2 in muscle can be used as an IMF-specific biomarker.Selection for the absolute amount of C18:2 is expected to deliver a similar response outcome as selection for IMF at restrained BT.Further genetic analysis of the C18:2 metabolic pathway may provide new insights into differential fat deposition among adipose tissues and on candidate genes for molecular markers targeting specifically for one of them.

Changes of Intramuscular Fat Composition,Lipid Oxidation and Lipase Activity in Biceps femoris and Semimembranosus of Xuanwei Ham During Controlled Salting Stages

Fatty acid composition of neutral lipids （NLs）, phospholipids （PLs） and free fatty acids （FFAs） from intramuscular fat （IMF）, lipid oxidation and lipase activity in muscle Semimembranosus （SM） and msucle Biceps femoris （BF） of dry-cured Xuanwei ham during the 90-d salting stages were analysed. The salt content increased from 0.34 to 3.52%in BF and from 0.10 to 5.42%in SM during the 90 d salting stage, respectively. PLs of IMF in both BF and SM decreased 54.70%（P〈0.001） and 34.64%（P〈0.05）, furthermore, the saturated fatty acids （SFA）, monounsaturated fatty acids （MUFA） and polyunsaturated fatty acids （PUFA） of PLs in both muscles were hydrolysed almost isochronously. FFAs were increased from 0.46 g 100 g-1 lipids to 2.92 g 100 g-1 lipids in BF at the end of salting, which was lower than SM （from 1.29 g 100 g-1 lipids to 9.70 g 100 g-1 lipids）. The activities of acid lipase, neutral lipase and acid phospholipase all remained active in the 90 d. The thiobarbituric acid reactive substances （TBARS） was slowly increased to 1.34 mg kg-1 muscle in BF and to 2.44 mg kg-1 muscle in SM during the salting stage. In conclusion, the controlled salting process prompted the hydrolysis of PLs of IMF notably and increased the lipid oxidation of muscles within some limits.

Vitamin A regulates intramuscular adipose tissue and muscle development:promoting high-quality beef production

During growth in cattle,the development of intramuscular adipose tissue and muscle is dependent upon cell hyperplasia(increased number of adipocytes)and hypertrophy(increased size of adipocytes).Based on the results of previous studies,other adipose tissue depots(e.g.,perirenal and subcutaneous)develop from the fetal stage primarily as brown adipose tissue.The hyperplastic stage of intramuscular adipose is considered to develop from late pregnancy,but there is no evidence indicating that intramuscular adipose tissue develops initially as brown adipose tissue.Hyperplastic growth of intramuscular adipose continues well into postweaning and is dependent on the timing of the transition to grain-based diets;thereafter,the late-stage development of intramuscular adipose tissue is dominated by hypertrophy.For muscle development,hyperplasia of myoblasts lasts from early(following development of somites in the embryo)to middle pregnancy,after which growth of muscle is the result of hypertrophy of myofibers.Vitamin A is a fat-soluble compound that is required for the normal immunologic function,vision,cellular proliferation,and differentiation.Here we review the roles of vitamin A in intramuscular adipose tissue and muscle development in cattle.Vitamin A regulates both hyperplasia and hypertrophy in in vitro experiments.Vitamin A supplementation at the early stage and restriction at fattening stage generate opposite effects in the beef cattle.Appropriate vitamin A supplementation and restriction strategy increase intramuscular adipose tissue development(i.e.,marbling or intramuscular fat)in some in vivo trials.Besides,hyperplasia and hypertrophy of myoblasts/myotubes were affected by vitamin A treatment in in vitro trials.Additionally,some studies reported an interaction between the alcohol dehydrogenase-1C(ADH1C)genotype and vitamin A feed restriction for the development of marbling and/or intramuscular adipose tissue,which was dependent on the timing and level of vitamin A restriction.Therefore,the feed strategy of vitamin A has the visible impact on the marbling and muscle development in the cattle,which will be helpful to promote the quality of the beef.

Factors influencing time course of pain after depot oil intramuscular injection of testosterone undecanoate

Pain following depot intramuscular （IM） injection of oil vehicle-based drugs has been little studied. This study aimed to determine prospectively the prevalence,determinants,severity and functional consequences of pain during the week after IM injection of 1 000 mg testosterone undecanoate （TU） in a 4-mL castor oil vehicle. Androgendeficient men receiving regular T replacement therapy at an academic andrology clinic were recruited to report pain scores using a coloured visual linear analogue scale at seven times over the first day and daily for a week after a deep IM gluteal injection. The time course and covariables influencing pain scores were analysed by mixed model analysis of variance （ANOVA）. Following 168 injections in 125 men,pain was reported by 80% of men,peaking immediately after injection,reaching only moderate severity,lasting 1-2 days and returning to baseline by day 4.The pain required little analgesic use and produced minimal interference in daily activities. The time course of pain scores was reproducible in the 43 men who underwent two consecutive injections. Pain was more severe in men who had an earlier painful injection,but less severe in older and more obese men. There were negligible differences in post-injection pain experience between experienced nurses administering injections. Deep IM gluteal injection of depot TU in 4-mL castor oil is well tolerated and post-injection pain is influenced by earlier painful injection experience,as well as age and obesity.

MiR-146a-5p targeting SMAD4 and TRAF6 inhibits adipogenensis through TGF-β and AKT/mTORC1 signal pathways in porcine intramuscular preadipocytes

Background: Intramuscular fat(IMF) content is a vital parameter for assessing pork quality. Increasing evidence has shown that microRNAs(miRNAs) play an important role in regulating porcine IMF deposition. Here, a novel miRNA implicated in porcine IMF adipogenesis was found, and its effect and regulatory mechanism were further explored with respect to intramuscular preadipocyte proliferation and differentiation.Results: By porcine adipose tissue miRNA sequencing analysis, we found that miR-146a-5p is a potential regulator of porcine IMF adipogenesis. Further studies showed that miR-146a-5p mimics inhibited porcine intramuscular preadipocyte proliferation and differentiation, while the miR-146a-5p inhibitor promoted cell proliferation and adipogenic differentiation. Mechanistically, miR-146a-5p suppressed cell proliferation by directly targeting SMAD family member 4(SMAD4) to attenuate TGF-β signaling. Moreover, miR-146a-5p inhibited the differentiation of intramuscular preadipocytes by targeting TNF receptor-associated factor 6(TRAF6) to weaken the AKT/mTORC1 signaling downstream of the TRAF6 pathway.Conclusions: MiR-146a-5p targets SMAD4 and TRAF6 to inhibit porcine intramuscular adipogenesis by attenuating TGF-β and AKT/mTORC1 signaling, respectively. These findings provide a novel miRNA biomarker for regulating intramuscular adipogenesis to promote pork quality.

Conservative management of cervical pregnancy with intramuscular administration of methotrexate and KCl injection: Case report and review of the literature

We report the case of a cervical pregnancy successfully treated with intramuscular injection of methotrexate(MTX) and intramniotic administration of potassium chloride. A 41-year-old woman was admitted to our Department with the suspicion of ectopic pregnancy. Transvaginal ultrasound revealed empty endometrialcavity, gestational sac within the cervical canal and embryonic echo measuring crown rump length 1.5 mm. Serum beta human chorionic gonadotropine(β-HCG) was measured 28590 IU/L. No cardiac activity was detected. The diagnosis of a cervical pregnancy was made. Patient was treated with intramuscular administration of methotrexate(50 mg/m2) in combination with ultrasoundguided intramniotic injection of KCl(2 meq/mL). Gradual decrease of β-HCG levels as well as ultrasound observation of collapsed gestational sac was observed. No curettage was necessitated. Patient was discharged on day 10 th and was set in follow-up on a weekly basis. β-HCG values were measured < 10 IU/L on 56 th day after MTX administration. Intramuscular administration of MTX may be effective in treatment of cervical pregnancy without additional interventional measures.

A selected population study reveals the biochemical mechanism of intramuscular fat deposition in chicken meat

Background:Increasing intramuscular fat(IMF)is an important strategy to improve meat quality,but the regulation mechanism of IMF deposition needs to be systematically clarified.Results:A total of 520 chickens from a selected line with improved IMF content and a control line were used to investigate the biochemical mechanism of IMF deposition in chickens.The results showed that the increased IMF would improve the flavor and tenderness quality of chicken meat.IMF content was mainly determined both by measuring triglyceride(TG)and phospholipid(PLIP)in muscle tissue,but only TG content was found to be decisive for IMF deposition.Furthermore,the increase in major fatty acid(FA)components in IMF is mainly derived from TGs(including C16:0,C16:1,C18:1n9c,and C18:2n6c,etc.),and the inhibition of certain very-long-chain FAs would help to IMF/TG deposition.Conclusions:Our study elucidated the underlying biochemical mechanism of IMF deposition in chicken:Prevalent accumulation of long-chain FAs and inhibitions of medium-chain FAs and very long chain FA would jointly result in the increase of TGs with the FA biosynthesis and cellular uptake ways.Our findings will guide the production of high-quality chicken meat.

The relationship between body mass index, thickness of subcutaneous fat, and the gluteus muscle as the intramuscular injection site

An intramuscular injection (IMI) is an injection given directly into the central area of a specific muscle. Certain medicines need to be administered by the gluteal route for these to be effective. The aim of this study was to determine the influence of body mass index (BMI), subcutaneous fat, and muscular thickness of the dorsogluteal IMI site among healthy Japanese women. There were 39 healthy female subjects who volunteered and met the criteria. Their ages ranged from 40s to 60s (50.82 ± 6.04). With the data collected using the B-mode ultrasound images of the dorsogluteal site, it was found that the distance from the epidermis to the under-fascia (DEUF) of the gluteus maximus was dissimilar between the subject’s right and left buttocks. It was found that the distance from the epidermis to the iliac bone (DEI) was significantly more on the right than on the left buttocks. In the case of an adult Japanese woman with a BMI of 21 or more, the DEUF of the gluteus medius was found to be about 30 mm, and the DEI was approximately 50 mm or more. Based on these findings, it is recommended that a needle length of 38 mm (1.5 inches) can be safely used to administer IMIs to the gluteus medius muscle to effectively and efficiently deliver medications through the IMI route.

Comparison of Gluteal Muscle Intramuscular Injection Sites of Japanese Healthy Subjects: Considerations for Optimal Insertion of Injection Needle Length

Long Acting Injectable (LAI) medications for patients with schizophrenia is commonly administered to relieve their symptoms. Through shared decision-making and clinical evidence-based, psychiatrists should systematically offer LAIs to all patients requiring long-term antipsychotic treatment as a first-line treatment. Gluteal intramuscular (IM) injection requires accurate insertion of needles into the specific muscle area, often the outer upper quadrant of the buttocks, in order to achieve the required blood concentration. The purposes of this study were to compare the “Distance from the Epidermis to the Under-Fascia (DEUF)” and “Distance from the Epidermis to the Iliac Bone (DEB)” of the buttocks IM injection sites at the dorsogluteal and ventrogluteal sites among healthy Japanese volunteer subjects, and to identify the optimal insertion injection needle length. The DEUF and DEB at the gluteal regions were measured by ultrasonography. Welch’s one-way analysis of variance was used to compare the DEUF and the DEB at the gluteal IM injection regions. There was no statistically significant difference observed between the right and left mean values of DEUF for Hochstetter and Clark’s point at the ventrogluteal sites, and the Four and Three-way split or Double Cross point at the dorsogluteal sites. However in the DEB, the Hochstetter’s point (P < 0.01) at ventrogluteal site on the right side, and Clark’s point (P < 0.05) were significantly shorter than the Double Cross point at dorsogluteal sites (F = 4.38). The left buttocks Hochstetter’s point was significantly shorter than the Double Cross point (F = 4.38, P < 0.01). These results, however, did not establish a statistically significant difference in the DEUF among injection sites. It was considered that the difference in the DEB depended on muscle volume and thickness in the gluteal injection sites.

Appropriate Needle Lengths Determined Using Ultrasonic Echograms for Intramuscular Injections in Japanese Infants

Adjuvanted vaccines are recommended for administration through an intramuscular route. The Centers for Disease Control and Prevention (CDC) has recommended the anterolateral thigh using a 22 - 25-G 25-mm (1 inch) needle for infants, injected at a 90° into the skin surface, and using a 16 mm (5/8 inch) for newborns. Appropriate needle lengths may differ depending on racial backgrounds. In the present study, the thickness of the epidermis and lengths from the skin surface to the muscle fascia and bone were measured using ultrasonic echograms in order to determine suitable needle lengths for Japanese infants aged 2, 3, 4, 5, 6, and 12 - 15 months old. The thickness of the epidermis was 1.44 - 1.54 mm (95% CI), and the lengths from the skin surface to the muscle fascia and bone were 11.52 - 12.28 mm (95% CI), and 25.66 - 26.93 mm (95% CI), respectively, at the anterolateral thigh. At the center of the deltoid muscle, skin thickness was similar to that at the thigh, furthermore the lengths from the skin surface to the muscle fascia and bone were 8.49 - 9.10 mm (95% CI), and 17.38 - 18.31 mm (95% CI), respectively. The lengths from the skin surface to the muscle fascia and bone were 1 - 2 mm shorter in 2-month-old infants than those in older generations. Therefore, the appropriate needle length for intramuscular injections in Japanese infants was 16 mm (5/8 inch) at any age and sites, and with 25 mm (1 inch) needles at a 90° angle being associated with the risk of over-penetration.

Myristic Acid(MA) Promotes Adipogenic Gene Expression and the Differentiation of Porcine Intramuscular Adipocyte Precursor Cells

Intramuscular fat （IMF） content is considered to be a key factor that affects the marbling, tenderness, juiciness and lfavor of pork. To investigate the effects of myristic acid （MA） on the differentiation of porcine intramuscular adipocytes, cells were isolated from longissimus dorsi muscle （LDM） and treated with 0, 10, 50 or 100μmol L-1 MA. The results showed that MA signiifcantly promotes the differentiation of intramuscular adipocytes in a dose-dependent manner. MA also led to a parallel increase in the expression of peroxisome proliferator activated receptor-γ（PPARγ） and adipose-related genes, such as glucose transporter 1 （GLUT1）, lipoprotein lipase （LPL）, adipocyte fatty acid binding protein 4 （FABP4/aP2）, fatty acid translocase （FAT）, acetyl-CoA carboxylaseα（ACCα）, adipose triglyceride lipase （ATGL） and fatty acid synthase （FASN）. However, no signiifcant effects of MA were observed on the expression of CAAT enhancer binding protein-α（C/EBPα） or hormone sensitive lipase （HSL）. The expression of pyruvate dehydrogenase kinase 4 （PDK4） was increased by MA during the early stages of differentiation （day 1-3）. In addition, MA also increased the absolute content of C14 （P〈0.001） and saturated fatty acids （SFA） （P〈0.05） to varying degrees, but no effects were observed on other fatty acids. These results suggest that MA might be able to enhance the IMF content of pork and increase the accumulation of myristic and myristoleic acid in muscle, which might have beneifcial implications for human health.

In vivo prediction of intramuscular fat in pigs using computed tomography

One hundred and four pure-bred Norwegian Duroc boars were CT (computed tomography) scanned to predict the in vivo intramuscular fat percentage in the loin. The animals were slaughtered and the loin was cut commercially. A muscle sample of the m. Longissimus dorsi was sampled and analyzed by the use of near-infrared spectroscopy. Data from CT images were collected using an in-house MATLAB script. Calibration models were made using PLS (partial least square) regression, containing independent data from CT images and dependent data from near-infrared spectroscopy. The data set used for calibration was a subset of 72 animals. The calibration models were validated using a subset of 32 animals. Scaling of independent data and filtering using median filtering were tested to improve predictions. The results showed that CT is not a feasible method for in vivo prediction of intramuscular content in swine.