The relationship between acute rejection and chronic rejection is highly dependent on specific MHC matching: a multi-strain rat heterotopic heart transplant study

BACKGROUND: The impact of acute rejection, immunosuppression, and infection, specifically cytomegalovirus infection, on the development of chronic rejection in the cardiac allograft, has been the subject of a large number of investigations. One of the difficulties in finding associations has been the marked immunologic heterogeneity of the patient population coupled with the lack of the ability to HLA match. Furthermore, the ideal animal model, which duplicates as well as controls for this immunologic heterogeneity, is lacking. METHODS: To try to simulate differences in HLA matching, immunosuppression regiments and cytomegalovirus infection, heterotopic heart transplantation was performed in two separate, complete MHC mismatch, rat strain combinations (WF-LEW, BN-LEW) requiring chronic immunosuppression and employing four separate immunosuppression/infection protocols. Animals were followed for 6 months, killed, and rejection and vascular changes were scored blinded to the group. RESULTS: The mean vascular and acute rejection scores were not significantly different between treatment regiments for either specific strain combination. There was a trend for the subtherapeutic groups to have higher vascular scores. Overall, there were no significant differences in vascular scores between the WF-LEW and BN-LEW groups (1.25+/-0.18 vs. 1.13+/-0.20, P=NS). Similar numbers of WF-LEW and BN-LEW exhibited cellular infiltration and necrosis of the allograft, but the intensity of the response (rejection score) was more severe in the WF-LEW combination (4.54+/-0.22 vs. 3.92+/-0.21, P=0.052) when limiting the analysis to those with myocyte necrosis. There was no significant correlation between acute rejection and vascular lesion severity in the WF-LEW combination (r=0.22, P=NS) but a high correlation between these parameters in the BN-LEW combination (r=0.74, P<0.0001). CONCLUSIONS: These data suggest that, although acute rejection and chronic rejection are related, MHC matching may influence their interdependence. These data also may explain why the clinical association between acute and chronic rejection is difficult to demonstrate.     

Infants born to narcotic dependent mothers: Physical growth patterns in the first 12 months of life

Objectives: To describe the physical growth patterns of infants born to narcotic dependent mothers (INDM) over a 12 months period and, if possible, to relate the growth to drug taking patterns during pregnancy.
Methodology: The growth of a cohort of 43 INDM was measured during the first 12 months of life. Weight and length measurements were compared with percentile charts and converted to Z scores. Questionnaire data about drug taking practices, demographic variables and the neonatal period (including withdrawal scores) were obtained.
Results: Twenty-four (55.8%) of INDM had evidence of neonatal drug withdrawal requiring treatment with phenobarbitone. At birth, Z scores for weight and length indicated relative intrauterine growth retardation. By 12 months, there had been some catch up growth, but Z scores for weight and length were still below zero. Persistent weight retardation at 12 months was correlated with methadone dosage during pregnancy, but not the need for phenobarbitone therapy.
Conclusions: The growth patterns of INDM in the first 12 months of life indicated that at birth there was evidence of intrauterine growth retardation, but by 12 months the growth was little different from the rest of the community. There appears to be some influence of narcotic agents taken while pregnant on subsequent growth of INDM.     

Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats

Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is a contaminant of the human food supply, particularly in parts of Africa and Asia. AFB1-induced changes in gene expression may play a part in the development of the toxic, immunosuppressive and carcinogenic properties of this fungal metabolite. An understanding of the-role of AFB1 in modulating gene regulation should provide insight regarding mechanisms of AFB1-induced carcinogenesis. We used three PCR- based subtractive techniques to identify AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential display PCR (DD-PCR), representational difference analysis (RDA) and suppression subtractive hybridization (SSH). Each of the three techniques identified AFB1- responsive genes, although no individual cDNA was isolated by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH were found to represent eight genes that are differentially expressed as a result of AFB1 exposure. Genes whose mRNA levels were increased in cultured primary rat hepatocytes after AFB1 treatment were corticosteroid binding globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin, C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When liver RNA from AFB1-treated male F344 rats was evaluated for transferrin, CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen. Analysis of the potential function of these genes in maintaining cellular homeostasis suggests that their differential expression could contribute to the toxicity associated with AFB1 exposure.      

Defective radiation signal transduction in ataxia-telangiectasia cells

PURPOSE: The product of the gene ATM mutated in the human genetic disorder ataxia-telangiectasia (A-T) is predominantly present in the nucleus Compatible with a role in DNA-damage recognition and cell-cycle control. However, ATM is also present outside the nucleus in cytoplasmic and membrane associated vesicles, which may explain the more general signalling defect in A-T. This led us to investigate signalling events initiated by ionizing radiation, remote from the nucleus. MATERIALS AND METHODS: A-T and control lymphoblastoid cells were employed to study radiation-induced signalling at the level of protein activation using immunoprecipitation and immunoblotting. Flow cytometry was used to determine mobilization of intracellular Ca2+. RESULTS: Lymphoblastoid cells from A-T patients were found to be defective in the radiation-induced activation of protein tyrosine kinase p53/p56lyn. In control cells Ca2+ was mobilized in response to gamma-radiation largely from internal stores, and increased significantly over a 20 min period. This mobilization of Ca2+ was either absent or increased very slowly in A-T cells post-irradiation. The same pattern of release was observed after treatment with the radiometric agent, streptonigrin. In addition the phospatidylinositol 3-kinase (PI3-kinase) inhibitor wortmannin suppressed the release of Ca2+. CONCLUSION: These data demonstrate that ionizing radiation activates lyn kinase and leads to the release of Ca2+, and-for the first time-that these steps are ATM-dependent.     

Glutamatergic dysfunction in OCD.

The role of glutamatergic dysfunction in the pathophysiology of OCD has hardly been explored despite recent reports implicating glutamatergic dysfunction in OCD. We decided to investigate CSF glutamate levels in adult OCD probands compared to psychiatrically normal controls. In total, 21 consenting psychotropic drug-na?ve adult OCD patients, diagnosed using SCID-IV-CV, and 18 consenting psychiatrically normal controls with age within 10 years of age of the patients, who did not have any history of head injury or neurological illness, were included into the study. Aseptically collected and stored CSF samples obtained from the patients and control subjects were used for glutamate estimation, which was carried out by a modification of the procedure described by Lund (1986). CSF glutamate (micromol/l) level was found to be significantly higher [F(1,31)=6.846, p=0.014] in OCD patients (47.12+/-4.25) compared to control subjects (41.36+/-3.63) on analysis of covariance. There was no effect of gender, age, duration of illness, Y-BOCS score, or CGI-S score on CSF glutamate levels. Our study provides preliminary evidence implicating glutamatergic excess in the pathophysiology of OCD, which needs to be further explored by studies from other centers involving larger sample sets from different age groups.     

Visual impairment and refractive errors in school children in Andhra Pradesh,India

Purpose:Addressing childhood vision impairment (VI) is one of the main goals of the World Health Organization’s (WHO) combating blindness strategies. The primary aim of this study was to estimate the prevalence of VI, causes, and its risk factors in school children in Krishna district, Andhra Pradesh, India.Methods:Children aged 4–15 years were screened in schools using the 6/12 Snellen optotype by trained community eye health workers, and those who failed the test and those reported or found to have obvious eye conditions were referred to primary (VC), secondary (SC), or tertiary (TC) care centre appropriately, where they underwent a complete eye examination including cycloplegic refraction and fundus examination.Results:A total of 56,988 children were screened, of whom 51.18% were boys. The mean age was 9.69 ± 3.26 years (4–15 years). Overall, 2,802/56,988 (4.92%) children were referred to a VC, of which 632/56,988 (1.11%) required referral to SC/TC. PVA of <6/12 was found in 1.72% (95% confidence interval [CI]: 1.61–1.83). The prevalence of refractive error (corrected and uncorrected) was 2.38% (95% CI: 2.26–2.51) and myopia was 2.17% (95% CI: 2.05–2.29). In multivariable analysis, older children, those in urban schools, private schools, and children with a disability had an increased risk of VI and myopia. Additionally, the risk of myopia was higher among girls than boys. Of those referred and reached SC/TC, 73.64% were due to avoidable causes.Conclusion:Childhood VI prevalence was 1.72% in this region. Uncorrected refractive error (URE) was the major cause of VI in children. Older age, schools in urban locations, private schools, and the presence of disability were associated with the risk of VI among children.     

选择性头部降温对胎羊缺血性脑损伤纹状体神经元凋亡和星形胶质细胞增殖的影响

目的研究选择性头部降温对缺血性脑损伤胎羊纹状体神经元凋亡和星形胶质细胞增殖的影响。方法胎羊于妊娠117~124d时通过双侧颈动脉阻塞30min造成双侧脑缺血损伤,损伤后将胎羊随机分为:损伤组(n=10)、2h低温组(损伤后2h开始亚低温治疗,n=7)和6h低温组(损伤后6h开始亚低温治疗,n=8),另设正常对照组(n=5)。通过冷循环水进行选择性头部降温,取脑组织用免疫组化法检测胎羊纹状体caspase-3(半胱天冬氨酸酶-3),GFAP(胶质纤维酸性蛋白)和PCNA(增殖细胞核抗原)的表达。结果①纹状体神经元凋亡:正常对照组中,caspase-3表达极少(11.00±13.77),损伤组caspase-3免疫阳性细胞为177.70±48.69,明显增加(P=0.000),损伤后2h治疗组(54.14±39.44,P=0.000)和损伤后6h治疗组(122.43±52.36,P=0.017)均能减少caspase-3免疫阳性细胞。②纹状体星形胶质细胞增殖:与正常对照组(163.40±21.98)相比,缺血性脑损伤组的GFAP免疫阳性细胞明显增多(433.25±66.69,P=0.000),损伤后2h开始亚低温治疗(219.50±35.31,P=0.000)和损伤后6h开始亚低温治疗(272.50±86.20,P=0.000)均能减少GFAP免疫阳性细胞。③纹状体PCNA阳性细胞的表达:在正常对照组中,PCNA免疫阳性细胞较少,为153.40±12.46,缺血性脑损伤组的PCNA免疫阳性细胞明显增多(353.70±45.60,P=0.000),损伤后2h开始亚低温治疗(187.14±26.26,P=0.000)和损伤后6h开始亚低温治疗(230.25±67.46,P=0.000)均能减少PCNA免疫阳性细胞。结论亚低温可以抑制纹状体神经元的凋亡和星形胶质细胞的增殖,该作用可能为选择性头部降温的脑保护作用机制之一。     

Measurement of basilar membrane vibrations and evaluation of the cochlear condition

The experimental procedure for measuring basilar membrane responses to acoustic signals is described. The surgical procedure developed for opening the cochlea with minimal trauma is presented. Each experiment included sound pressure level measurements to define the input signal, cochlear microphonic (CM) measurements to monitor the cochlear condition, interferometric measurements and histological evaluation of the cochleas. The characteristic frequency (CF) and the sensitivity at CF for the basilar membrane response is correlated with the change of CM response observed in six animals. It is demonstrated that both tuning characteristics are extremely sensitive to cochlear trauma as evidenced by changes of CM.