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Biomedical subjects

Y Sidi

Publications and source records attributed to Y Sidi.

At least 91 records · Page 5Linked to original sources
PubMed1990

Serum cobalamin and transcobalamin levels in systemic lupus erythematosus.

PURPOSE: The purpose of this study was to assay serum cobalamin levels in patients with systemic lupus erythematosus (SLE) as there are few case reports on the association of pernicious anemia and SLE. PATIENTS AND METHODS: Serum cobalamin levels were assayed in 43 female SLE patients by a radio-dilution assay using purified intrinsic factor. RESULTS: Cobalamin levels were found to be significantly lower in the SLE group compared with a normal control group, eight of whom (18.6%) had serum cobalamin levels equal to or lower than 180 pg/mL (mean: 129.25 +/- 40.05 pg/mL). None of the SLE patients had been found to have pernicious anemia. The transcobalamin II level and unsaturated vitamin B12 binding capacity, but not the cobalamin level, were positively correlated with SLE activity. CONCLUSION: Our results may indicate a subtle cobalamin deficiency in SLE patients without pernicious anemia.

Adolescent↗
PubMed1990

Developmental changes in the activity of enzymes of purine metabolism in rat neuronal cells in culture and in whole brain.

The activities (Vmax) of several enzymes of purine nucleotide metabolism were assayed in premature and mature primary rat neuronal cultures and in whole rat brains. In the neuronal cultures, representing 90% pure neurons, maturation (up to 14 days in culture) resulted in an increase in the activities of guanine deaminase (guanase), purine-nucleoside phosphorylase (PNP), IMP 5'-nucleotidase, adenine phosphoribosyltransferase (APRT), and AMP deaminase, but in no change in the activities of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), adenosine deaminase, adenosine kinase, and AMP 5'-nucleotidase. In whole brains in vivo, maturation (from 18 days of gestation to 14 days post partum) was associated with an increase in the activities of guanase, PNP, IMP 5'-nucleotidase, AMP deaminase, and HGPRT, a decrease in the activities of adenosine deaminase and IMP dehydrogenase, and no change in the activities of APRT, AMP 5'-nucleotidase, and adenosine kinase. The profound changes in purine metabolism, which occur with maturation of the neuronal cells in primary cultures in vitro and in whole brains in vivo, create an advantage for AMP degradation by deamination, rather than by dephosphorylation, and for guanine degradation to xanthine over its reutilization for synthesis of GMP. The physiological meaning of the maturational increase in these two ammonia-producing enzymes in the brain is not yet clear. The striking similarity in the alterations of enzyme activities in the two systems indicates that the primary culture system may serve as an appropriate model for the study of purine metabolism in brain.

Adenosine Monophosphate↗
PubMed1990

Systemic sclerosis and chronic lymphocytic leukaemia.

The association between the CREST (calcinosis, Raynaud phenomena, oesophageal hypomotility, sclerodactyly and telangiectasia, variant of systemic sclerosis and chronic lymphocytic leukaemia is described in three patients. The present description raises the possibility that the association of chronic lymphocytic leukaemia and systemic sclerosis is non-random.

Aged↗
PubMed1990

Acute coronary events following cisplatin-based chemotherapy.

Six patients with no previous signs or symptoms suggestive of coronary artery disease developed acute coronary ischemia/infarction shortly after cis-diamine-dichloroplatinum II (cisplatin) -based chemotherapy. In two patients this was the sole chemotherapeutic agent used. One patient underwent coronary angiography which disclosed no pathology, but following which, while on a calcium channel blocking agent regimen, he had an uneventful course of chemotherapy with cisplatin. Documentation of cisplatin-related vascular events is important in view of the growing number of patients who undergo cisplatin-based chemotherapy.

Aged↗
PubMed1990

Coexistence of low secretion of gonadotropins and ACTH in a patient with gonadal dysgenesis and pituitary tumor.

A 56-year-old woman with gonadal dysgenesis and pituitary adenoma is described. The unusual feature in this patient was the coexistence of a low gonadotropin level with secondary ACTH deficiency rather than the high gonadotropin level usually found in gonadal dysgenesis. Secretion of the other pituitary hormones was normal. Several hypotheses for such an unusual combination are presented.

Adenoma↗
PubMed1989

Adult onset Still's disease.

Three patients with adult onset of Still's disease are presented. Common early findings were: septic fever, polyarthralgia, leukocytosis, neutrophilia and elevated sedimentation rate. All of them had abnormal liver function tests which returned to normal values following corticosteroid therapy. It is proposed that hepatic abnormalities in adult onset of Still's disease reflect the basic disease process.

Adult↗
PubMed1989

Growth inhibition and induction of phenotypic alterations by tiazofurin: differential effects on MCF-7 breast cancer and HBL-100 breast cell lines.

The effect of the nucleoside anti-metabolite tiazofurin (TR) was examined on the growth and phenotypic alterations of MCF-7 breast cancer and HBL-100 normal breast cell lines. TR was shown to inhibit MCF-7 cell growth. This inhibition could be reversed by exogenous addition of guanosine. The anti-proliferative effect of TR is accompanied by phenotypic alterations that include lipid accumulation and an increase in alkaline phosphatase activity. In contrast to MCF-7 cells, the HBL-100 breast milk derived cell line is relatively resistant to inhibition by TR. Alkaline phosphatase is not affected by TR and untreated cells accumulate lipid droplets, similar to TR-treated MCF-7 cells. Determination of GTP and ATP pools in both cell lines revealed that TR markedly reduces GTP content in MCF-7 cells. In HBL-100 cells, TR induces only a small decrease in GTP and does not affect ATP levels. The prototypic IMP dehydrogenase inhibitor, mycophenolic acid (MA), markedly inhibits HBL-100 cell growth, similarly to its effect on MCF-7 breast cancer cells. These findings may suggest differential metabolism of TR in MCF-7 and HBL-100 cells.

Adenosine Triphosphate↗
PubMed1989

Guanine ribonucleotide metabolism in human red blood cells: evidence for a high rate of GMP dephosphorylation.

The flux rates through the metabolic pathways affecting the maintenance of GuRN pool in intact human RBC were studied. Normal RBC, incubated in KRBB, exhibited a markedly higher accumulation in nucleotides of Gu than of Hx. Addition of 8-AGuo, a potent inhibitor of PNP, resulted in a marked increase in the accumulation of label in the nucleosides, in Ino following incubation with Hx, and in Guo following incubation with Gu, indicating a very high rate of IMP and GMP degradation to bases through their respective nucleosides. Most of the degradation of GMP is by dephosphorylation to Guo, rather than through reductive deamination to IMP. The ultimate fate of IMP in RBC is its degradation to Ino and consequently to Hx. The contribution of AdRN or of IMP to the GuRN pool is negligible. The results indicate that concerning IMP and GMP, human RBC contain very active futile cycles, nucleotide----nucleoside----base----nucleotide, catalyzed by 5'-nucleotidase, PNP, and HGPRT. The operation of the complete cycles is essential for the maintenance of GuRN and the IMP pool size. These results may explain the finding of reduced GTP content in RBC from patients with an inborn deficiency of PNP or of HGPRT.

Erythrocytes↗
PubMed1989

[Infection with Mycobacterium avium complex in the nonimmunocompromised host].

Pulmonary infection due to mycobacterium avium complex has been considered exceedingly rare, with only 50 case reports in the literature until 1982. However, during the past decade the dissemination of the acquired immune deficiency syndrome has been accompanied by a marked increase in the frequency of reported infections due to this agent, although infection in the noncompromised host remains rare. We describe an 80-year-old man who was not immunocompromised but who was infected with mycobacterium avium complex.

Aged↗
PubMed1988

Theophylline prolongs survival and decreases renal damage in female NZB/W F-1 mice.

Theophylline (Th) augments suppressor T cell activity (STCA). We attempted to test this immunoregulatory effect of TH on survival, renal disease and several immunologic parameters in NZB/W F-1 female mice. The median survival was 274 +/- 50 days for the mice receiving Th and 235 +/- 39 days for the controls (p less than 0.01). Assessment of the extent of renal damage by light microscopy revealed activity scores of 1.86 +/- 2 and 4.71 +/- 2.7 for the Th and control groups, respectively (p less than 0.001). T cell activity of NZB/W F-1 lymphocytes was assessed by the local xenogeneic GVH reaction. The mean GVH reaction volume of the Th group was significantly lower (9.3 +/- 8.8 mm3) as compared to controls (31 +/- 9 mm3) (p less than 0.001). The proportion of Lyt-1 versus Lyt-2 spleen lymphocytes did not change significantly. It is concluded that Th prolongs survival and decreases the extent of renal damage in female NZB/W F-1 mice.

Animals↗
PubMed1985

Differential metabolism of deoxyribonucleosides by leukaemic T cells of immature and mature phenotype.

Experimental evidence has indicated that T lymphoblasts are more sensitive to deoxynucleoside toxicity than are B lymphoblasts. These data have led to the use of purine enzyme inhibitors as selective chemotherapeutic drugs in the treatment of T cell malignancies ranging from T cell acute lymphoblastic leukaemia to cutaneous T cell lymphomas. We have compared the toxicities of 2'-deoxyadenosine, 2'-deoxyguanosine, and thymidine for T cell lines derived from patients with T cell acute lymphoblastic leukaemia with those for mature T cell lines derived from patients with cutaneous T cell leukaemia/lymphoma. We have found that both deoxynucleosides are far less toxic to the mature T cell lies than to T lymphoblasts and that the mature cells accumulate much lower amounts of dATP and dGTP when exposed to deoxyadenosine and deoxyguanosine, respectively. Similar studies performed on peripheral blood cells from patients with T cell leukaemias of mature phenotype and on peripheral blood T cells demonstrate similar low amounts of deoxynucleotide accumulation. Measurements of the activities of several purine metabolizing enzymes that participate in deoxynucleoside phosphorylation or degradation do not reveal differences which would explain the toxicity of deoxynucleosides for immature, as compared to mature, T cells. We conclude that deoxynucleoside metabolism in leukaemic T cells varies with their degree of differentiation. These observations may be relevant to the design of chemotherapeutic regimes for T cell malignancies.

Adult↗