Vessel density and En-face segmentation of optical coherence tomography angiography to analyse corneal vascularisation in an animal model

Background:Optical coherence tomography angiography(OCTA)is a novel non-invasive angiography technology that has recently been extensively studied for its utility in anterior segment imaging.In this study,we compared a split-spectrum amplitude decorrelation angiography(SSADA)OCTA and an optical micro-angiography(OMAG SD)OCTA system to current angiographic technique,indocyanine green angiography(ICGA),to assess corneal vascularisation in an animal model.Methods:We imaged 16 rabbits,(one eye per animal)with corneal vascularisation using SSADA OCTA(AngioVue;Optovue Inc.,USA),OMAG OCTA(Angioscan;RS-3000 Nidek Co.Ltd.,Japan)and ICGA in the same region of interest of the cornea at successive time-points.We then analysed all scanned images for vessel density measurements and used paired t-tests and Bland-Altman plots to examine for significant differences.The en-face segmentation images from each of the OCTA scans were also extracted and were matched at every 50μm segmentation to be compared for vessel density at the respective depths.Results:Bland-Altman plots revealed a good agreement between all three imaging techniques(P>0.05)for all vessel density measurements computed,and the ranges of 95%limit of agreement were acceptable from a clinical perspective.No significant difference was reported,with ICGA(μ=16.52±8.94%)being more comparable to the OMAG OCTA(μ=16.23±9.51%;p=0.50)than the SSADA OCTA(μ=17.09±7.34%;p=0.33)system.Also,a good correlation value(r>0.9)was obtained when comparing the vessel density measurements of the en-face segmentations between the OCTA systems.Conclusions:Comparable vessel density quantification between the two OCTA systems,and with ICGA was obtained.Segmentation analysis of the vasculature at different depths showed varied performance in the two OCTA systems relative to each other.The implications of the study may help to aid in the development of better OCTA algorithms for the anterior segment and its use in clinical translational research.

Atrial Myxoma with a Dual Coronary Artery Supply

Primary cardiac tumours are rare, with myxoma being the most common benign heart tumour. The prevalence of coronary disease or neovascular in patients with atrial myxomas is high, yet angiography is not routinely performed. Echocardiography is preferred for evaluation of myxoma, where coronary angiography clarifies the vascular supply of the tumour and may alter the surgical planning. We here report an interesting and rare case of a left atrial myxoma hyper vascularised by two anomalous arteries, from right coronary artery and circumflex artery demonstrated by preoperative coronary angiography. The mass was successfully excised and the diagnosis of cardiac myxoma was confirmed via histopathology. A review of the value of coronary angiography in detecting myxoma neovascularization is provided. Offering additional valuable information, coronary angiography can alter the surgical approach and may therefore be considered prior to myxoma resection.

A Clinical Study of Pterygium and Results of Treatment by Excision and Limbal Autograft or Augmented with Post-Op Mitomycin C

Aim: To prospectively analyze the clinical profile of pterygium and to compare results of management by excision with limbal conjunctival autograft or postoperative topical Mitomycin C drops. Methodology: Study was conducted over a period of 23 months, at a tertiary eye care hospital including 80 eyes of 80 patients who underwent surgery, out of which 40 underwent limbal conjunctival autograft and the remaining 40 underwent pterygium excision followed by Mitomycin C after fulfilling the inclusion criteria. A detailed history was taken and recorded regarding the disease with reference to age, occupation, residence, exposure to dust and hot wind. The extent of corneal involvement by the pterygium was noted. The patients were followed after one week and then monthly for a year. BCVA were noted on every visit and slit lamp examination was done for recurrence, sclera thinning and corneal vascularisation. Result: 80 eyes of 80 patients were enrolled with male preponderance, out of which 40 underwent limbal conjunctival autograft (gr. A) and the remaining 40 underwent pterygium excision followed by Mitomycin C (gr. B). All patients were in the age group of 23 to 70 years. The study showed a higher incidence of pterygium in the age group of 41-50 years with male preponderance probably due to chronic dryness, and exposure to ultraviolet light, dust, and hot winds. The right eye was more affected than the left eye, and nasal side was more involved than the temporal side. The recurrence among group A was 2 out of 40 with a recurrence rate of 5% and among group B was 3 out of 40 with a recurrence rate of 7.5%. Scleral thinning was seen in two cases (5%) in patients who underwent pterygium excision followed by Mitomycin C. Conclusion: Conjunctival limbal autograft and postoperative MMC (0.02%) are both safe and effective adjuncts to primary pterygium surgery. The main prejudices against autografting are the expertise and time required for the procedure. The recent use of biologic adhesives to fixate the autograft in place may simplify the procedure. Age of the patients was strongly associated with recurrence regardless of which procedure was used. More research needs to be done to delve into this seemingly innocuous pathology of conjunctiva to effectively manage the disease condition.

肾上腺素β受体和胆碱能M受体对边缘细胞钾离子转运的调控

耳蜗血管纹边缘细胞向内淋巴转运钾离子对耳蜗内淋巴的生成,电化学特征的维持起到直接作用。钾离子经边缘细胞转运的过程除了受细胞内外离子浓度、膜电压的调控外还受细胞膜受体及细胞内信号转导系统调节。目前研究发现肾上腺素β受体促进边缘细胞的钾离子转运;胆碱能M受体则抑制边缘细胞的钾离子转运。肾上腺素β受体和胆碱能M受体对边缘细胞钾离子转运的调控作用具有重要的临床意义。

Ototoxic effects and mechanisms of loop diuretics

Over the past two decades considerable progress has been made in understanding the ototoxic effects and mechanisms underlying loop diuretics. As typical representative of loop diuretics ethacrynic acid or furosemide only induces temporary hearing loss, but rarely permanent deafness unless applied in severe acute or chronic renal failure or with other ototoxic drugs. Loop diuretic induce unique pathological changes in the cochlea such as formation of edematous spaces in the epithelium of the stria vascularis, which leads to rapid decrease of the endolymphatic potential and eventual loss of the cochlear microphonic potential, summating potential, and compound action potential. Loop diuretics interfere with strial adenylate cyclase and Nat/Kt-ATPase and inhibit the Na-K-2Cl cotransporter in the stria vascularis, however recent reports indicate that one of the earliest effects in vivo is to abolish blood flow in the vessels supplying the lateral wall. Since ethacrynic acid does not damage the stria vascularis in vitro, the changes in Nat/Kt-ATPase and Na-K-2Cl seen in vivo may be secondary effects results from strial ischemia and anoxia. Recent observations showing that renin is present in pericytes surrounding stria arterioles suggest that diuretics may induce local vasoconstriction by renin secretion and angiotensin formation. The tight junctions in the blood-cochlea barrier prevent toxic molecules and pathogens from entering cochlea, but when diuretics induce a transient ischemia, the barrier is temporarily disrupted allowing the entry of toxic chemicals or pathogens.

ENDOCOCHLEAR POTENTIAL AND POTASSIUM CONCENTRATION RECORDING IN MINIPIG COCHLEA

Objective To record the endocochlear potential (EP) and calculate potassium concentration [K+] in Minipig cochleae. Methods We used multi-barreled electrodes to measure the EP and the potential, [K + ]. EP and potassium electrode recording were made in 9 cochleae from 5 minipigs to get normal EP values. Results The average EP value in the cochlea from the minipigs was 77.3 ± 14 mV. The average [K+] for the minipigs was 147.1 ± 13 mM. Conclusions The EP and potential, [K + ] in minipigs are lower than in the human and rodents. This may be the reason why porcine ABR thresholds are slightly higher than humans and rodents.

Expression Patterns and Implications of LaminBl in Rat Cochleae

LaminB1,a major component of the nuclear lamina,is a potent regulator of cellular proliferation and senescence and also known to be essential for neuronal migration and brain development.However,the expression patterns of LaminB1 in the rat cochleae are still not fully revealed.Utilizing immunofluorescence.Western blotting,and quantitative real-time PCR,we identified the distribution and expression of LaminB1 in the rat cochleae.Immunofluorescence staining indicated that LaminBl was mainly localized in the auditory hair cells(HCs),spiral ganglion cells(SGC),stria vascularis(STV,including spiral ligament),Reissner's membrane(RM),and limbus laminae spiralis(LLS).Western blotting analysis illustrated that the distribution of LaminBl in rat cochleae was characterized by tissue specificity.The LaminB1 protein was expressed more in SGC and basilar membrane(BM)than in STV.Meanwhile,the mRNA expression of LaminB1 displayed difference in cochlear tissues.These observations preliminarily revealed the expression patterns of LaminB1,providing a theoretical basis for further study on the role of LaminB1 in auditory function.

The Ultrastructural Characteristics of the Stria Vascularis, Spiral Prominence and Spiral Ligament in Guinea Pigs

The mean length of the stria vascularis (SV) and the basilar membrane of four normalguinea pigs measured by means of surface preparation was 21.11 mm and 19. 90 mm respectively,and the mean width of their apical turns of SV and the turns of the cochlear basis was 0. 44 mmand 0. 86 mm respectively. The ultrastructure of SV, spiral ligament (SL) and spiral prominence(SP) of both ears of eight guinea pigs were observed by scanning electron microscopy(SEM) andtransmission electron microsoopy(TEM). There were a large number of coated vesicles in thesupranuclear region of SV, some opened to the endolymph. A great number of folding cytoplasmicprojections were filled with small vesicles The capillary network was extremely rich indicating thatthe endolymph could be secreted and absorbed by SV. The cellular conjunction in the SV. SL andSP formed an effective barrier. It has not been proved in this study that the melanin offers resistanceto acoustic stimulation.

Optical coherence tomography angiography for the anterior segment

Optical coherence tomography angiography(OCTA)is a rapid and non-invasive technique for imaging vasculature in the eye.As OCTA can produce high-resolution cross-sectional images and allow depth-resolved analysis for accurate localization of pathology of interest,it has become a promising method for anterior segment imaging.Furthermore,OCTA offers a more patient-friendly alternative to the conventional invasive dye-based fluorescent angiography.However,conventional OCTA systems are typically designed and optimized for the posterior segment of the eye,and thus using OCTA for anterior segment imaging can present several difficulties and limitations.In this review,we summarized the recent developments and clinical applications in anterior segment OCTA(AS-OCTA)imaging,such as for the cornea,iris,sclera and conjunctiva.We also compared commercially available OCTA systems,discussed the limitations of adapting current OCTA technology for the anterior segment imaging,and proposed possible future directions for AS-OCTA systems.AS-OCTA provides potential for future clinical applications such as diagnosis of corneal and iris pathologies,pre-operative surgical planning,assessment of new antiangiogenic therapeutics or evaluation of limbal stem cell deficiency.With further development,OCTA for anterior segment imaging in the clinics may become common in the near future.

耳蜗血管纹产生耳蜗内电位的机理

耳蜗内淋巴具有独特的离子成分,以及相对于外淋巴+80mv^+90mv的耳蜗内电位。血管纹对维持耳蜗内环境的稳定有重要作用,它在向内淋巴转运钾离子的过程中产生耳蜗内电位。本文对血管纹产生耳蜗内电位的各种相关机理的研究进展进行综述。

内耳损伤的修复与再生

噪声、药物、重金属等因素可导致内耳损伤。内耳损伤的研究发现，不同机制不同类型的损伤通常始发于内耳的特定区域。本文集中探讨内耳损伤后，对特定区域的干预以帮助内耳损伤后的修复与再生。

DISTRIBUTION AND LOCATION OF IMMUNOREACTIVE ATRIAL NATRIURETIC PEPTIDES IN COCHLEAR STRIA VASCULARIS OF GUINEA PIG

The distribution and location of atrial natriuretic peptides(ANP) in the cochlear stria vaseularis of normal guinea pigswere studied to find out regional regulating factors of cochlearblood flow (CBF) and productive foundation of cochlearendolymph by ABC immunocytochemistry and immunoele-ctronmicroscopy. The ANP-IR products were seen in the striavascularis of the 1-4 turns of the lateral wall of the cochlea,more markedly along its margin; and were negative in the spi-ral ligaments. Immunoelectronmicroscopically, a plenty ofsphericals of 250-350nm in diameter were noted in thecytoplasm of marginal and intermediate cells, but few in thebasal cells. The results suggest that the cochlear striavascularis had the function of secreting ANP in the guinea pig.

Surgical debulking, lymphatico venous anastomosis, vascularised lymph node transfer in lower limb lymphoedema

Lymphoedema is a chronic debilitating disease of the lymphatic system that occurs due to either abnormal development or damage of the lymphatics resulting from cancer or infection.The optimal treatment of lymphoedema is still elusive.Management is tailored according to clinical features,investigations and expectations of each patient.Lymphoedema patients should undergo a trial of conservative management with compression therapy,manual lymphatic drainage and external sequential compression devices.Early lymphoedema is treated by lymphovascular anastomosis,where the lymph vessels are connected to the subdermal veins by supermicrosurgery.In late cases when the limb is fibrotic,vascularised lymph node transfers are done,where lymph nodes are transferred from a healthy area to the affected area.In advanced cases,when the limb is fibrotic with cutaneous folds and skin changes,surgical debulking is done.In lymphoedema,along with accumulation of lymphatic tissue,there is also fat deposition,which can be removed by liposuction.One should be conversant with all treatment modalities to provide the lymphoedema patient with optimal care.