Biomedical subjects
Publications and source records attributed to D Vassilopoulos.
This experimental study describes the pressure changes of the descending colon before and after total and selective vagotomy combined with Finney's pyloroplasty as estimated by telemetry. The results obtained from the study of 20 dogs show that the motility of the descending colon is extremely reduced after total vagotomy with no change after selective vagotomy.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Causes of chromosomal nondisjunction is one of the remaining unanswered questions in human genetics. In order to increase our understanding of the mechanisms underlying nondisjunction we have performed a molecular study on trisomy 8 and trisomy 8 mosaicism. We report the results on analyses of 26 probands (and parents) using 19 microsatellite DNA markers mapping along the length of chromosome 8. The 26 cases represented 20 live births, four spontaneous abortions, and two prenatal diagnoses (CVS). The results of the nondisjunction studies show that 20 cases (13 maternal, 7 paternal) were probably due to mitotic (postzygotic) duplication as reduction to homozygosity of all informative markers was observed and as no third allele was ever detected. Only two cases from spontaneous abortions were due to maternal meiotic nondisjunction. In four cases we were not able to detect the extra chromosome due to a low level of mosaicism. These results are in contrast to the common autosomal trisomies (including mosaics), where the majority of cases are due to errors in maternal meiosis.
OBJECTIVE: To determine the origin of the extra chromosome in trisomy 8 in spontaneous abortions. METHODS: We analyzed 4 cases of nonmosaic trisomy 8 in 1st-trimester spontaneous abortions and their parents with DNA polymorphism analysis using microsatellite DNA markers. RESULTS: In 3 cases the extra chromosome was maternal in origin and in 1 case paternal in origin. In 2 of the cases the nondisjunction had occurred in maternal meiosis, while the other 2 cases were consistent with a postzygotic (mitotic) origin of the additional chromosome. CONCLUSION: Although a small number of cases studied, these results suggest differences from the common autosomal trisomies 21, 18, 16, and 13 where the vast majority of cases are due to errors in maternal meiosis.
OBJECTIVE: Chronic hepatitis C virus (HCV) infection is associated with an array of autoimmune laboratory and clinical manifestations. The goals of our study were to identify host and/or virological factors that are implicated in the pathogenesis of these manifestations. METHODS: We performed a detailed prospective study of various demographic, virological, biochemical, immunological (including lymphocyte subsets, Fc gamma-receptor and HLA class-II genotyping), histological and host genetic parameters in 3 well defined subgroups of HCV patients (n = 40): patients with liver disease only (group I, n = 11) or with laboratory (group II, n = 20) and clinical (group III, n = 9) autoimmune manifestations. RESULTS: Group III patients, mainly with features of mixed cryoglobulinemia, were older, with higher levels of rheumatoid factor and circulating cryoglobulins while they tended to have a longer estimated disease duration compared to the other two groups of patients. We did not identify any specific immunological features that could differentiate symptomatic versus asymptomatic patients, except from the elevated soluble interleukin-2 receptor levels. An increased frequency of the R/R131 FcR gamma IIIA and the NA1/NA1 Fc gamma RIIIB genotypes was observed in our total HCV population, regardless of autoimmune manifestations, compared to historical controls. No statistically significant differences in HLA class II allele frequencies was detected between patient subgroups or in comparison to healthy controls. CONCLUSIONS: Chronically infected HCV patients with symptomatic mixed cryoglobulinemia display a number of unique characteristics that differentiate them from asymptomatic patients with chronic hepatitis C.
The recurrence risks for major depression among the relatives of patients with delusional depression have been calculated using a computer program. The risk tables have been based on the data from the 454 first-degree relatives of 77 probands with delusional depression, the 503 first-degree relatives of 76 non-delusional probands and the 980 first-degree relatives of 153 controls. The results showed that: the familial aggregation of the delusional depression seem to follow the multifactorial pattern of inheritance (segregation analysis), the heritability of the delusional depression was found to be 62, the recurrence risk varies from 0.5% to 36.2% for the various relatives and tables for recurrence risks are provided.
Explore the source record for details and available documents.
The predominance of type 2 fibres in the periphery of the muscle fascicle is a phenomenon attributed to local factors or to the adaptation of the muscle to functional needs. As the majority of relevant studies has been performed on quadriceps muscle of males, the purpose of this study was to examine other muscles along with quadriceps, in females as well as in males, with parallel morphometric analysis of fibres, in order to determine whether differences in size exist in addition to differences in proportion. Cryostat sections (ATPase, pH 9.4) were studied from 13 quadriceps femoris, 13 biceps brachii and 11 deltoid muscles taken at autopsy from 11 males and 8 females. The number and smallest diameter of type 1 and 2 fibres were counted and the percentage and mean diameter of the two types of fibres were calculated in the interior and the periphery of randomly selected fascicles. We found that: the predominance of type 2 fibres in the periphery is constant in all muscles studied, regardless of sex and age; there is a progressive age-related reduction in the diameter of type 2 fibres.
Size and distribution of 2 histochemical types of muscle fibers within the human muscle fascicle were investigated. Cryostat sections (ATPase, pH 9.4) were studied from 15 quadriceps femoris, 15 biceps brachii and 15 deltoid muscles taken at autopsy from 12 males and 9 females who had no history of neuromuscular disease. The number and the lesser diameter of type 1 and type 2 fibers were counted and percentage and mean diameter of the 2 types of fibers were calculated separately for periphery and interior of randomly selected fascicles. The results showed that a progressive age-related reduction of the diameter of type 2 fibers is observed and the predominance of type 2 fibers in the periphery is a constant finding in all muscles studied, regardless of sex and age.
Novel data have emerged which attempt to characterize the biochemical abnormalities that are exhibited by lupus immune cells. Lupus lymphocytes display abnormal antigen-receptor-mediated signaling, consisting of increased Ca2+ mobilization and increased protein tyrosyl phosphorylation that are independent of disease activity. Abnormalities in the expression and function of co-stimulatory molecules (B7-CD28 and CD40-CD40L) have been established. Transcription of cytokine genes and the methylation of DNA which affects multiple genes are also abnormal. Finally, aberrations of the apoptosis of lupus immune cells are contributors to the pathogenesis of the disease.