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Biomedical subjects

S Peter

Publications and source records attributed to S Peter.

At least 37 records · Page 2Linked to original sources
PubMed1993

[The methodology of percutaneous nephrostomy. The two-step technique].

A new two-step technique for percutaneous nephrostomy with a newly designed nephrostomy set is described. The technique combines the advantages of the a direct introducing method (one-step nephrostomy) with an introducing trocar and the "three-step" technique with an initial puncture by a needle and insertion of a rigid guide wire. Evaluation of the different techniques in 195 patients revealed no disadvantage of the new technique compared with the three-step technique.

Blood Loss, Surgical↗
PubMed1992

Multiple drug resistance gene expression in human renal cell cancer is associated with the histologic subtype.

Overexpression of p170 glycoprotein, the product of the multiple drug resistance (mdr) gene, has been associated with resistance to various cytotoxic drugs used in the treatment of human neoplasms. Normal renal epithelial cells express p170 as a function of their secretory capacity. Because renal cell carcinomas (RCC) respond poorly to chemotherapeutic regimens, p170 expression was studied in primary RCC. Such expression was measured in 40 human RCC and normal kidney tissues using immunohistochemical staining with the monoclonal antibody C-219. Staining intensities of the whole tumor and of different areas of the cryostat sections were transformed into digital numbers using an algorithm designed for this purpose. In most tumors, an inhomogeneous staining pattern and a correlation between grade of differentiation and C-219 immunoreactivity was observed. A comparison of the tumors according to their histopathologic subtypes showed clear differences. The means (range) of the staining intensities of the different types of RCC: clear cell carcinoma Grade 1 (n = 3), 2.0 (2.0 to 2.0); clear cell carcinoma Grade 2 (n = 19), 0.8 (0.0 to 2.9); clear cell carcinoma Grade 3 (n = 5), 0.1 (0.0 to 0.2); tubular carcinoma (n = 4), 2.0 (2.0 to 3.0); anaplastic carcinoma (n = 8), 0.05 (0.0 to 0.2); oncocytoma (n = 1), 0.0 (0.0 to 0.0); and normal kidney (n = 40), 0.5 (0.0 to 2.0). The differences between anaplastic, clear cell, and tubular carcinoma were significant (P less than 0.001 by Kruskal-Wallis test). In addition, the difference between the three subgroups of clear cell carcinoma was significant (P less than 0.01). It was concluded that the histopathologic subtypes of RCC correlate with the degree of mdr gene expression, as determined by staining with the C-219 monoclonal antibody.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Mutations in the ras protooncogenes are rare events in renal cell cancer.

Mutations in codon 12, 13 or 61 of one of the three ras genes, Ha-ras, Ki-ras, and N-ras, convert these genes into active oncogenes. To determine the role mutated ras genes play in the carcinogenesis of renal cell carcinoma, we analysed tumour DNA and unaffected renal tissue derived from 55 patients. The polymerase chain reaction technique was used to amplify DNA fragments containing Ki-, Ha-, and N-ras codons 12, 13, and 61. The amplified fragments were then probed on slot-blots with labeled mutation-specific oligomers. A single Ki-ras mutation (codon 12, gly- greater than val) was detected in a patient with a pT2N2M1 tumour. We concluded that ras oncogene mutations do not play an important role in the initiation of renal cell carcinoma.

Adult↗
PubMed1992

[Significance of oncogenes and growth factors in hypernephroma].

In all cells there are a number of genes that regulate cell division and growth. In an "activated" form they are called oncogenes and play a role in the carcinogenesis. The activation results from such alterations as point mutation and translocation or alterations with increased synthesis of genes and gene product. There are different oncogene families. Up to now only a small number have been tested in renal cancer cells.

Carcinoma, Renal Cell↗
PubMed1991

Expression of the hst-1 and c-kit protooncogenes in human testicular germ cell tumors.

Seventy testicular germ cell tumors were analyzed at the DNA and RNA levels for the c-kit, hst-1, and int-2 oncogenes using Northern and Southern blot analyses, respectively. There were significant differences in oncogene expression between seminomas and nonseminomas with c-kit being expressed in 24 of 30 (80%) seminomas but in only 3 of 40 (7%) nonseminomatous tumors (P = 0.0001, chi 2 test) and hst-1 being expressed in 24 of 38 (63%) nonseminomas but only 1 of 24 (4%) of seminomas (P = 0.0001, chi 2 test), demonstrating an inverse relationship in the expression pattern of these 2 oncogenes in human testicular germ cell tumors. A significant association between tumor stage and hst-1 expression in the nonseminoma group was found (P = 0.0002, chi 2 test). No gross alterations in the c-kit, hst-1, and int-2 loci were found at the DNA level and no int-2 mRNA expression was detected in any of the germ cell tumors examined.

Blotting, Southern↗
PubMed1991

Oncogenes and growth factors in renal cell carcinoma.

Oncogenes and growth factors play a role in normal cellular processes such as growth and differentiation. In addition, considerable circumstantial evidence indicates that these genes may be responsible for the induction and/or maintenance of human malignancies. There are different oncogene families; up to now only a small number has been tested in renal cancer cells.

Carcinoma, Renal Cell↗
PubMed1990

Inverse relationship of epidermal growth factor receptor and HER2/neu gene expression in human renal cell carcinoma.

Expression of the oncogenes, epidermal growth factor (EGF) receptor, HER2/neu, c-myc, and c-fos, in renal cell carcinoma and corresponding nonneoplastic kidney tissue of 30 patients has been analyzed by Northern blot analysis. In renal cell carcinoma an inverse relationship of EGF receptor and HER2/neu gene expression was detected, with high expression of the EGF receptor gene in 22 of 30 (73%) cases and low expression of the HER2/neu gene in 28 of 30 (93%) cases. Furthermore, altered expression of the oncogenes c-myc and c-fos was detected in renal cell carcinoma, which appears to be related to the tumor grade of malignancy. Additional Southern blot analysis of six renal cell carcinomas gave no indication of chromosomal rearrangement events or gene amplification.

Biomarkers, Tumor↗
PubMed1990

Decreased expression of the glutathione S-transferases alpha and pi genes in human renal cell carcinoma.

Using the polymerase chain reaction (PCR), a human kidney glutathione S-transferase (GST) alpha cDNA clone (GST alpha 12 K) was synthesized; it is identical to a known liver GST alpha cDNA clone except for one base change (G----A), indicating that an alpha class gene expressed in human kidney is similar to one expressed in human liver. Comparisons were made in the expression of GST alpha and GST pi between renal cell carcinoma and adjacent non-neoplastic tissue. Messenger RNA expression in 30 cases was determined by Northern blotting, and GST protein from nine of these cases was analyzed by HPLC. The GST alpha gene products were expressed at near-zero levels. The GST pi gene product was the predominant GST in tumors, but was decreased in absolute amount compared with control tissue, the tumor/control ratios for the GST pi gene obtained by Northern blots and HPLC analysis being 0.50 +/- 0.07 and 0.36 +/- 0.07 respectively. The resulting pattern in renal cell carcinoma therefore shows a predominance of GST pi. Since it is assumed that renal cell carcinoma derives from the proximal tubular epithelial cells which are high in GST alpha, this implies a dedifferentation in the GST expression pattern.

Blotting, Northern↗
PubMed1987

Transient hypoglycemic paraparetic syndrome in an elderly patient.

An elderly diabetic patient sustained a transient hypoglycemic paraparetic episode that was attributed to inappropriate administration of glyburide. There were no other predisposing causes to account for the transient hypoglycemia. The predominant clinical signs were paraparesis of the lower extremities, with the right side more affected than the left. The patient's paraparesis cleared within two hours after administration of 50 mL of 50 percent glucose intravenously.The management of a paraparetic syndrome should include an appraisal of all the predisposing factors and their correction. The mechanism that was deemed responsible for the patient's transient hypoglycemic paraparetic syndome was loss of cerebrovascular autoregulation in a vulnerable area (the vertebral-basilar artery distribution). In the elderly patient tight control of blood glucose levels should be avoided in view of the potential development of hypoglycemia and brain injury.

Aged↗
PubMed1986

Immunohistochemical and ultrastructural study of Sertoli cells in androgen insensitivity.

The ultrastructure of a perfusion-fixed gonad in a case of androgen insensitivity was studied using thin sections and freeze-fracture replicas. The distribution and arrangement of intermediate filaments in Sertoli cells was visualized immunohistochemically using an antibody against vimentin. Leydig cells lacked Reinke crystals, but contained all of the cytoplasmic organelles involved in steroid synthesis and additionally several lysosomes. The basement membrane and the basal lamina of the testicular tubules were considerably thickened. The testicular tubules consisted of gonocytes and Sertoli cells which had an immature nuclear structure, incomplete development of intercellular junctions and a primitive distribution pattern of intermediate cytoplasmic filaments. The previously reported differences in electron density of Sertoli cell cytoplasm are a non-specific feature without significance to Sertoli cell maturation.

Adult↗
PubMed1985

Heterogeneous estrogen receptor levels detected via multiple microsamples from individual breast cancers.

Twenty-six surgical breast cancer specimens were subjected to multiple estrogen receptor (ER) assays with a microsample technique. In most tumors there were large variations in ER levels in samples taken from different regions of the same tumor. After correction of individual samples for differences in carcinoma content, such variations were not abolished. Nine of the 26 breast cancers, although positive overall, were devoid of ER in some regions. For ER-positive tumors the average coefficient of variation (CV) for intratumor ER levels was 86%, with a range from 25% to 200%. This is well above the CV obtained with repeat samples of homogeneous tissue (14%). These results suggest that many ER-positive cancers may be composed of cells with a variety of ER levels. An assessment of individual intratumor ER variability may have biologic and clinical significance.

Adult↗
PubMed1984

Delirium as the predominant manifestation of hyperparathyroidism: reversal after parathyroidectomy.

A 67-year-old woman who had primary hyperparathyroidism presented with delirium rather than dementia as the predominant psychologic manifestation. After surgical removal of a parathyroid adenoma, there was a dramatic improvement in mental status. Psychologic retesting at six weeks after discharge showed her to be well oriented to time, place, and person, with no impairment of cognitive capacity.

Adenoma↗
PubMed1983

[Treatment of chronic kidney failure in diabetes mellitus].

27 patients suffering from end stage diabetic renal failure were treated by hemodialysis (HD) [8], continuous ambulatory peritoneal dialysis (CAPD) [13] or kidney allotransplantation after previous dialysis (KT) [13]. The mean age of the patients was 39.8 +/- 9.8, 44.8 +/- 11.3 and 33.8 +/- 5.7 for HD, CAPD and KT groups respectively. The cumulative patient survival after 1 and 2 years of treatment was 24%/0%, 56%/0% and 70%/50% for HD, CAPD and KT treatment. The cumulative allotransplant survival amounted to 40% after 1 year and to 20% after 2 and 3 years. Causes of death included cardiovascular complications in 7 patients, especially during HD treatment; infections occurred in 6 patients during CAPD treatment and after kidney allografting. Hypertension persisted during HD treatment and disappeared in 1/3 of the patients after KT. Nonlethal cardiovascular problems were observed during all treatment regimens and were more prominent in HD patients. In 2 patients, 3 amputations of the legs had to be performed after KT. Visual power deteriorated in more than half of the patients on HD and in one third during CAPD; it remained stable in half of the patients after KT. Neuropathy deteriorated during HD, was stable during CAPD and improved after KT. Rehabilitation was better during CAPD or after KT than during HD. The results of kidney replacement therapy in diabetics are worse than in non diabetic patients due to extrarenal organ damage. Early renal transplantation might prove to ameliorate this situation.

Adult↗