Extended criteria brain-dead organ donors:Prevalence and impact on the utilisation of livers for transplantation in Brazil

BACKGROUND Despite its association with higher postoperative morbidity and mortality,the use of extended criteria donor(ECD)livers for transplantation has increased globally due to the high demand for the procedure.AIM To investigate the prevalence of ECD in donation after brain death(DBD)and its impact on organ acceptance for transplantation.METHODS Retrospective analysis of DBD organ offers for liver transplantation between 2017 and 2020 in a high-volume transplant centre.The incidence of the Eurotransplant risk factors to define an ECD(ET-ECD)among DBD donors and the likelihood of organ acceptance over the years were analysed.The relationship between organ refusal for transplantation,the occurrence,and the number of ET-ECD was assessed by simple and multiple logistic regression adjustment.RESULTS A total of 1619 organ donors were evaluated.Of these,78.31%(n=1268)had at least one ET-ECD criterion.There was an increase in the acceptance of ECD DBD organs for transplantation(1 criterion:from 23.40%to 31.60%;2 criteria:from 13.10%to 27.70%;3 criteria:From 6.30%to 13.60%).For each addition of one ETECD variable,the estimated chance of organ refusal was 64.4%higher(OR 1.644,95%CI 1.469-1.839,P<0.001).Except for the donor serum sodium>165 mmol/L(P=0.310),all ET-ECD criteria increased the estimated chance of organ refusal for transplantation.CONCLUSION A high prevalence of ECD DBD was observed.Despite the increase in their utilisation,the presence and the number of extended donor criteria were associated with an increased likelihood of their refusal for transplantation.

Association of donor hepatectomy time with liver transplantation outcomes: A multicenter retrospective study

BACKGROUND Prolonged donor hepatectomy time may be implicated in early and late complications of liver transplantation.AIM To evaluate the impact of donor hepatectomy time on outcomes of liver transplant recipients,mainly early allograft dysfunction.METHODS This multicenter retrospective study included brain-dead donors and adult liver graft recipients.Donor-recipient matching was obtained through a crossover list.Clinical and laboratory data were recorded for both donors and recipients.Donor hepatectomy,cold ischemia,and warm ischemia times were recorded.Primary outcome was early allograft dysfunction.Secondary outcomes included need for retransplantation,length of intensive care unit and hospital stay,and patient and graft survival at 12 months.RESULTS From January 2019 to December 2021,a total of 243 patients underwent a liver transplant from a brain-dead donor.Of these,57(25%)developed early allograft dysfunction.The median donor hepatectomy time was 29(23–40)min.Patients with early allograft dysfunction had a median hepatectomy time of 25(22–38)min,whereas those without it had a median time of 30(24–40)min(P=0.126).CONCLUSION Donor hepatectomy time was not associated with early allograft dysfunction,graft survival,or patient survival following liver transplantation.

Formation of Superoxide Radical and Hydrogen Peroxide Enhanced by Trinitrotoluene in Rat Liver, Brain, Kidney, and Testicle in Vitro and Monkey Liver in Vivo

Trinitrotoluene (TNT) increased the formation of adrenochrome from adrenaline and the formation of formaldehyde from methanol in rat liver mitochondria and microsomes in vitro as well as in monkey liver mitrochondria and microsomes in vivo. The effects were more prominent at higher TNT concentrations. These findings indicate that TNT enhances the production of superoxide radicals (O_2^-) and hydrogen peroxide (H_2O_2). The production of O_2^- was more prominent in systems containing added TNT than in those containing added benzyl viologen. H_2O_2 production by mitochondria was more pronounced in the liver than in other organs, but its production by microsomes was more pronounced in the brain than in other organs. The results suggest that TNT undergoes cycling reduction which produces oxidative stress. 1989 Academic Press, Inc.

Evaluation of the updated definition of early allograft dysfunction in donation after brain death and donation after cardiac death liver allografts

BACKGROUND:An updated definition of early allograft dysfunction(EAD) was recently validated in a multicenter study of 300 deceased donor liver transplant recipients.This analysis did not differentiate between donation after brain death(DBD) and donation after cardiac death(DCD) allograft recipients.METHODS:We reviewed our prospectively entered database for all DBD(n=377) and DCD(n=38) liver transplantations between January 1,2006 and October 30,2011.The incidence of EAD as well as its ability to predict graft failure and survival was compared between DBD and DCD groups.RESULTS:EAD was a valid predictor of both graft and patient survival at six months in DBD allograft recipients,but in DCD allograft recipients there was no significant difference in the rate of graft failure in those with EAD(11.5%) compared with those without EAD(16.7%)(P=0.664) or in the rate of death in recipients with EAD(3.8%) compared with those without EAD(8.3%)(P=0.565).The graft failure rate in the first 6 months in those with international normalized ratio ≥1.6 on day 7 who received a DCD allograft was 37.5% compared with 6.7% for those with international normalized ratio <1.6 on day 7(P=0.022).CONCLUSIONS:The recently validated definition of EAD is a valid predictor of patient and graft survival in recipients of DBD allografts.On initial assessment,it does not appear to be a useful predictor of patient and graft survival in recipients of DCD allografts,however a study with a larger sample size of DCD allografts is needed to confirm these findings.The high ALT/AST levels in most recipients of DCD livers as well as the predisposition to biliary complications and early cholestasis make these parameters as poor predictors of graft failure.An alternative definition of EAD that gives greater weight to the INR on day 7 may be more relevant in this population.

Location and expression of neurotrophin-3 and its receptor in the brain of human embryos during early development

BACKGROUND： Cell culture in vitro trials have demonstrated that neurotrophin-3 （NT-3） can enhance the survival of sensory neurons and sympathetic neurons, and can also support embryo-derived motor neurons. This effect is dependent on nerve growth factor on the surface of cells. Understanding the role of NT-3 and its receptor in the early development of human embryonic brains will help to investigate the correlation between early survival of nerve cells and the microenvironment of neural regeneration. OBJECTIVE： To observe the proliferation of cerebral neurons in the development of human embryonic brain, and to investigate the location, expression and distribution of NT-3 and its receptor TrkC during human brain development. DESIGN, TIME AND SETTING： An observation study on cells was performed in the Department of ttuman Anatomy, Histology and Embryology, Chengdu Medical College in September 2007. MATERIALS： Fifteen specimens of flesh human embryo, aged 6 weeks, were used in this study. METHODS： The proliferation of cerebral neurons was detected using proliferating cell nuclear antigen, and the immunocytochemistry ABC technique was applied to observe the location, expression and distribution of NT-3 and its receptor TrkC in the brain of the human embryo. MAIN OUTCOME MEASURES： Location, expression and distribution of NT-3 and its receptor in the brain of the human embryo. RESULTS： In the early period （aged 6 weeks） of human embryonic development, proliferating cell nuclear antigen-positive reactive substances were mainly observed in the nucleus of the forebrain ventricular zone and subventricular zone, and the intensity was stronger in the subventricular zone than the forebrain ventricle. NT-3 positive reactive substance was mainly distributed in the cytoblastema of the forebrain neuroepithelial layer and nerve cell process, while TrkC was mainly distributed in the cell membrane of the forebrain ventricular zone and subventricular zone. During embryonic development, NT-3 and TrkC showed a positive immune reaction to a greater or lesser extent in ependymal epithelium. CONCLUSION： During early human embryonic development, cerebral nerve cells proliferate in the ventricular zone and subventricular zone, and NT-3 is expressed in the neural axon. The results show that the highly expressed NT-3 could promote the proliferation of neural axons and maintain the neuron body＇s survival.

Differential regulation of glutathione S-transferase Yb1mRNA levels in rat prostate, liver and brain by androgen

Northern blot analysis of glutathione S-transferase (GST) Yb1 mRNA in different tissues of male and female rats revealed that its tissue-specific transcription patterns were highly sex hormone related. Although the GST Yb1 mRNA could be detected in most of the tissues examined at various levels, the highest abundance was observed in the ventral prostate, uterus and liver, which were the main target tissue for androgen, estrogen and glucocorticoid respectively The effect of androgen on the transcription of GST Yb1 was also tissue-specific. Since androgen withdrawal by castration caused the up-regulation of GST Yb1 mRNA in the ventral prostate but down-regulation in the liver and no effect in the brain, evaluation of this system for studying the regulation mechanisms of gene expression by which androgen exerts its differential effects has been discussed.

Intracranial pressure monitoring in the perioperative period of patients with acute liver failure undergoing orthotopic liver transplantation

Acute liver failure(ALF)may result in severe neurological complications caused by cerebral edema and elevated intracranial pressure(ICP).Multiple pathogenic mechanisms explain the elevated ICP,and newer hypotheses have been described.While invasive ICP monitoring(ICPM)may have a role in ALF management,these patients are typically coagulopathic and at risk for intracranial hemorrhage.ICPM is the subject of much debate,and significant heterogeneity exists in clinical practice regarding its use.Contemporary ICPM techniques and coagulopathy reversal strategies may be associated with a lower risk of hemor-rhage;however,most of the evidence is limited by its retrospective nature and relatively small sample size.

Protective effects of glycine pretreatment on brain-death donor liver

BACKGROUND: Morphological and functional changes commonly occur in livers of brain-death donors. Preven- tion of liver injury from brain-death will benefit the results of transplantation. This study was conducted to evaluate the protection effects of glycine on the liver of brain-death donor. METHODS: Fourty-two male Wistar rats were randomly divided into brain-death donor (BDD) group (B), glycine pretreatment group with BDD (G), and strychnine pre- treatment group with BDD(S). For these groups, brain death model was established in donor rats and liver trans- plantation was performed subsequently utilizing microsur- gical techniques. After the establishment of the model and during cold rinsing of liver donors or liver reperfusion of recipients, glycine was given at a dose of 0. 6 mmol, 25 μmol and 25 μmol in the group G, and a same dose of gly- cine and strychnine (1000 :1) was prescribed for the group S, but nothing for the group B. Before cold rinsing at 2 and 6 hours after portal vein(PV) reperfusion, blood sam- ples were taken from infrahepatic vena cava (IHVC) to de- termine the levels of alanine aminotransferase (ALT), as- partate aminotransferase (AST), tumor necrosis factor al- pha (TNF-α) and hyaluronic acid (HA). At 6 hours after PV reperfusion, graft samples were fixed for morphological observation and apoptosis of hepatocytes was detected using the TUNEL method. RESULTS: Before liver cold rinsing and at 2 and 6 hours af- ter PV reperfusion, the serum levels of ALT, AST, TNF-α, HA and apoptosis index (AI) in the groups B and S were significantly higher than those in the group G (P <0.05). There was no significant difference between the groups B and S (P>0.05). Electron microscopy showed that Kupffer cells were activated and hepatic cells injured more obvious- ly in the groups B and S than in the group G. CONCLUSION: Glycine pretreatment can improve the via-bility of the liver of the brain-death donor rat.

Pathological Characteristics of Liver Allografts from Donation after Brain Death Followed by Cardiac Death in Pigs

Donation after brain death followed by circulatory death （DBCD） is a unique practice in China. The aim of this study was to define the pathologic characteristics of DBCD liver allografts in a porcine model. Fifteen male pigs （25-30 kg） were allocated randomly into donation after brain death （DBD）, donation after circulatory death （DCD） and DBCD groups. Brain death was induced by aug- menting intracranial pressure. Circulatory death was induced by withdrawal of life support in DBCD group and by venous injection of 40 mL 10% potassium chloride in DCD group. The donor livers were perfused in situ and kept in cold storage for 4 h. Liver tissue and common bile duct samples were col- lected for hematoxylin and eosin staining, TUNEL testing and electron microscopic examination. Spot necrosis was found in hepatic parenchyma of DBD and DBCD groups, while a large area of necrosis was shown in DCD group. The apoptosis rate of hepatocytes in DBD [（0.56±0.30）%] and DBCD [（0.50 ±0.11）%] groups was much lower than that in DCD group [（3.78±0.33）%] （P〈0.05）. And there was no significant difference between DBD group and DBCD group （P〉0.05））. The structures of bile duct were intact in both DBD and DBCD groups, while the biliary epithelium was totally damaged in DCD group. Under electron microscope, the DBD hepatocytes were characterized by intact cell membrane, well-organized endoplasmic reticulum, mild mitochondria edema and abundant glycogens. Broken cell membrane, mild inflammatory cell infiltration and sinusoidal epithelium edema, as well as reduced glycogen volume, were found in the DBCD hepatocytes. The DCD hepatocytes had more profound cell organelle injury and much less glycogen storage. In conclusion, the preservation injury of DBCD liver allografts is much less severe than that of un-controlled DCD, but more severe than that of DBD liver allografts under electron microscope, which might reflect post-transplant liver function to some extent.

Reuse of liver grafts following the brain death of the initial recipient

AIM: To determine if there is a reasonable prospect of success of a re-use liver transplantation.METHODS: We systematically searched for reports of liver graft re-use using electronic searches of PubMed and Web of Knowledge. We performed hand searches of references lists of articles reporting re-use of grafts.RESULTS: A systematic review of the literature reveals 28 liver transplantations using previously transplanted grafts. First and second recipients ranged in age from 4 to 72 years and 29 to 62 years respectively. Liver disease in the first recipient was varied including 5(18%) patients with fulminant liver failure who died subsequently of cerebral edema. The second transplanta-tion was performed after a median interval of 5 d(one day-13 years). Viral hepatitis was present in 3(11%) of the initial recipients and in 8(29%) of final recipients. Hepatocellular carcinoma was present in 6(21%) of the final recipients. Early survival after the final transplantation was 93%, whereas long-term survival was 78% with a mean follow-up of 23.3(3-120) mo.CONCLUSION: Outcomes of transplantation using previously transplanted grafts in this select population are similar to those seen with conventional grafts.

Aging Leads to Over-Expression of Na⁺/K⁺Pump Units in Liver and Na⁺/Ca²⁺Exchangers in Brain Cortex

The metabolic controlling of tissue hydration is the fundamental parameter determining cell functional activity and its dysfunction is the common consequence of any cell pathology, including aging. The aim of the present study is to reveal the differences of age-dependent metabolic controlling of cell hydration of excitable tissue such as brain cortex and non-excitable tissues such as liver and spleen. For this purpose, the age-dependent sensitivity of cell hydration in excitable and non-excitablet issues is studied through depressing metabolic activity by cooling and its activation by supplying animals with distilled water, by inactivation of Na+/K+ pump and activation of Na+/Ca2+ exchange in the reverse mode. The obtained data bring us to the conclusion that the metabolic regulation of cell hydration in excitable tissue is realized by the activation of electrogenic Na+/K+ pump and Na+/Ca2+ exchange in the cell membrane and the formation of endogen water by mitochondrial activity, while the regulation of cell hydration in non-excitable tissue is carried out only by the activity of mitochondrial function. Aging leads to an over-expression of Na+/K+ pump units in liver and Na+/Ca2+ exchanger in brain cortex of rats.

Chronic effect of olive oil on some neurotransmitter contents in different brain regions and physiological, histological structure of liver and kidney of male albino rats

Olive oil is an important source of mono-unsaturated fat and a prime component of the Mediterranean diet. The beneficial health effects of olive oil are due to both its high content of mono-unsaturated fatty acids and its high content of anti-oxidative substances. The objective of this study was to investigate the basis for the epidemiological information relating to the health benefits associated with the consumption of ex-tra-virgin olive oil (EVOO). The effect of olive oil on norepinephrine (NE), dopamine (DA), serotonin (5-HT) and gamm-aminobutyric acid (GABA) con-tents in different brain regions and histological structure of liver and kindey of male albino rats was studied. The chronic administration of olive oil (7.5 mg/kg body wt.) caused a significant increase in norepinephrine (NE), dopamine (DA) , serotonin (5-HT) and gamm-aminobutyric acid (GABA) con-tent in different brain regions (Cerebellum, striatum, cerebral cortex, hypothalamus, brain steam and hip-pocampus) of male albino rats. The increase in NE, DA, 5-HT, and GABA content in the different CNS areas of male albino rat may be due to the inhibition of Ca2+/calmodulin binding which plays an important role in the release of these neurotransmitters. The results, also, revealed that urea and creatinne con-centrations in rats with oral administration with olive oil were decreased. Meanwhile, the activities of the enzymes AsT, AlT and ALP were elevated. The pre-sent results indicated that there is no change in tis-sues of kidney after treated with virgin olive oil. Olive oil may potentially be safe for use as a sedative drug. improvement also led to the reductions in risk of Alzheimer’s and Parkinson’s diseases.

Acute liver failure following levetiracetam therapy for seizure prophylaxis in traumatic brain injury

This case report investigates an uncommon occurrence of drug induced acute liver injury directly associated with the administration of levetiracetam in a patient following traumatic brain injury.

Environmental Risk of Atrazine (Herbicide) to Brain, Gills and Liver Tissues of Fish <i>Ctenopharyngodon idella</i>(Valenciennes, 1844)

The current study investigates the toxic effects of acute dose of an endocrine disruptor atrazine on Grass carp (Ctenepharyngodon idella) using histopathological changes as biomarkers. Histopathology is promising field for research in aquatic toxicology, in this manner vital organs;brain, gills, and liver tissues were inspected histological after exposing to sublethal groupings of atrazine 0.025 and 0.03 μl/L for 3, 6, 9, 12 and 15 days individually with equal untreated control group. Against various doses, rapid movements, gulping of air and jumping of fish to scat from toxic medium were noticed. Various severe (+++) morphological modifications in tissue were documented in comparison with control group comprised of degenerated neurons, vacuolization, inflammatory cells infiltration and neural necrosis in brain tissue. The most well-known gills tissue alteration at all concentrations of atrazine was epithelial hyperplasia, desquamation, epithelial lifting and smaller aneurism while hepatic injuries were described by overcast expanding of hepatocytes esteemed as cloudy swelling of hepatocytes followed by karyolysis, karyohexis and dilation of sinusoids which shows that atrazine introduction upgraded the toxicosis impacts with the increase concentration, influenced the strength of the fish, inferable from histological inconsistencies.

Long-Term Animal Feeding Trial of the Refined Konjac Meal Ⅱ. Effects of the Refined Konjac Meal on the Aging of the Brain, Liver, and Cardiovascular Tissue Cells in Rats

Rats of both sexes were fed on a basal feed containing 1% refined konjac meal (RKM) for 18 months and the effects of RKM on the cell aging were observed. A comparable group fed on the basic feed was used as the control. Results obtained demonstrate that the long-term feeding of RKM to rats can delay the course of cell aging of the gliocyte, cadiomyocyte, and the endothelial cell of the large and medium arteriases, hence it is likely to delay the occurrence of arteriosclerosis and improve the functions of the brain, heart and vascular system.

Union examination of AFP,AFU,AFPL3 and γ-GT in early diagnosis of primary liver cancer

Objective To explore the significance of union examination of blood serum liver cancer tracers in the early diagnosis of liver cancer. Methods We observed and compared the level of blood serum liver cancer tracers armor embryo protein (AFP),crag algae glycosidase (AFU),armor embryo protein heteroplasmon (AFPL3) and γ-Gu Anxian transferase (γ-GT) in early time for primary liver cancer patients and hepatitis liver cirrhosis patients and those chronic hepatitis B patients who had liver cancer family history. Results Finally among the 30 patients in the early liver cancer group,23 were positive with AFP,20 with AFU,15 with AFPL3 and 21 with γ-GT. Five were found positive with blood serum AFP,AFPL3,AFU and γ-GT at the same time; 5 with AFP,AFPL3 and γ-GT; 5 with AFP,AFU and AFPL3; 7 with AFP,AFU and γ-GT. By contrast,in the control group,among the 30 hepatitis liver cirrhosis patients and those chronic hepatitis B patients with liver cancer family history,11 were found positive with AFP,3 with AFPL3,12 with AFU and 14 with γ-GT. None of the patients were found positive with union examination of AFP,AFPL3,AFU and γ-GT in the blood serum at the same time. Conclusion The union examination of AFP,AFU,AFPL3 and γ-GT is significant to the early diagnosis of primary liver cancer.

Research Progress of the Liver–Brain Cotreatment of Depression with Supplemented Danzhi Xiaoyao Powder

Traditional Chinese medicine(TCM)has unique advantages in preventing and treating depression based on holistic concepts and syndrome differentiation and treatment.Liver depression and spleen deficiency are the main syndrome of depression.Danzhi Xiaoyao powder has the efficacy of soothing the liver and relieving depression,nourishing blood,and strengthening spleen.Present studies have proven that it has antidepressant efficacy for the syndrome of liver depression and spleen deficiency.The basic research on pharmacodynamic substances has found that the main active ingredients of Danzhi Xiaoyao powder in the treatment of depression include bupleurum saponin,paeonol,gardenoside,angelica polysaccharide,sulfate polysaccharide,paeoniflorin,albiflorin,atractylone,etc.In clinical practice,Danzhi Xiaoyao powder is often modified to make it more suitable according to the characteristics of pathogenesis and changes in the disease condition.Our research group has found that“brain and spirit failure and liver failing to disperse”are the main pathogenesis of depression.Based on the theory of“liver–brain cotreatment,”the treatment principle of“dispersing the liver and relieving depression,strengthening brain and benefiting intelligence”was put forward.On the basis of Danzhi Xiaoyao powder,Shichangpu(Acori Tatarinowii Rhizoma)was added to enlighten the mind and Yuanzhi(Polygalae Radix)to calm the mind and benefit intelligence.The modified Danzhi Xiaoyao powder was formulated,and its clinical effects on depression were remarkable.Animal experiments also confirmed that modified Danzhi Xiaoyao powder can significantly improve the depression-like behavior of depression model rats and the mechanism may be related to the regulation of the hypothalamic–pituitary–adrenal axis,the increase of the content of 5-hydroxytryptamine,and norepinephrine,which provides a reference for the further promotion of the clinical application of modified Danzhi Xiaoyao powder in the treatment of depression.

Human Embryo Neuronal Culture <i>in Vitro</i>: A Model to Study Cellular Physiology, Receptors, Power and Toxicity of Cytostatic Drugs for Human Use

Neural cells cultures from human embryo brain of 9° - 11°W gestational age have been used to study ERα (Estrogens Receptor α) and to perform toxicity test for Mitomycin C and Methotrexate. Histochemical confirmation of cellular neuronal phenotype was based on histochemical evidence of NSE (Neuron Specific Enolase).The detection of ERα in neuronal cells was performed with a rabbit Monoclonal Antibody. ERα was absent both on neurons grown in vitro and on tissue brain specimens. This finding is apparently in contrast with the positive immunoreactivity of ERα and ERβ reported by other Authors on foetal and adult CNS (Central Nervous System). The absence of nuclear ERα on neurons in culture and in brain tissue specimens in our experiment is not in contrast with the relevant physiologic role of estrogens on nervous central system, but it could be correlated to the embryonic period of life and could represent a protection of male brain from an undue estrogens imprinting. The mitomycin C, alkylation agent, has shown in our experiment a major neurotoxic and cytostatic power in comparison with methotrexate. Our conclusion is that human embryo neuronal culture in vitro is a powerful instrument for physiology and human therapy for cancer and neurodegenerative diseases.

Effect of soothing liver therapy on oocyte quality and growth differentiation factor-9 in patients undergoing in vitro fertilization and embryo transfer

OBJECTIVE:To investigate the effect of Soothing liver therapy on infertile women undergoing in vitro fertilization and embryo transfer(IVF-ET)and to explore its mechanism.METHODS:Fifty-eight women with tubal infertility were randomized into two groups:30 in an experimental group treated with Xiaoyao powder(Shugan)plus gonadotropin-releasing hormone analog(GnRHa)/follicle-stimulating hormone(FSH)/human chorionic gonadotropin(hCG)and 28 in the control group who were treated with GnRHa/FSH/hCG only.The total gonadotropin(Gn)doses required,endometrial thickness,oocyte numbers,high quality embryo production rate and pregnancy rate of the two groups were compared.The concentration of growth differentiation factor-9(GDF-9)in follicular fluid was detected by western blotting and the expression of GDF-9 mRNA in granulosa cells was measured using reverse tran-scription-polymerase chain reaction amplification.RESULTS:In the experimental group,the Gn dose was significantly lower than that in the control group;the endometrial thickness,high quality embryo production and pregnancy rates were significantly higher and the expression of GDF-9 mRNA was also significantly higher than in the control group(all P<0.05).CONCLUSION:Shugan treatment can improve the pregnancy rate of women with tubal infertility;its mechanism is possibly related to the increased expression of GDF-9 in granulosa cells.

Ameliorating Effects of Thyroxine and Atropine in Phosphamidon Intoxicated Chick Embryos

The effects of thyroxine and atropine in ameliorating phosphamidon intoxication in chick embryos was studied. Treatment of phosphamidon significantly enhanced the moriality and abnormalityrates, decreased the average body weights, and cholinesterase activity in chick embryos. When thyroxine was administered to the phosphamidon intoxicated embryos, the above parameters changedsignificantly, indicating an ameliorating effect of thyroxine against phosphamidon intoxication in chick embryos. The combined thyroxine and atropine therapy did not further improve the ameliorating effect. Since in many respects chick embryo development parallels that of mammalian embryos,a short-term use of thyroxine as a protective agent against organophosphate toxicity might be useful