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Biomedical subjects

R Stein

Publications and source records attributed to R Stein.

At least 19 recordsLinked to original sources
PubMed1992

Dissociation between release and gene expression of gonadotropin alpha-subunit in gonadotropin-releasing hormone-stimulated alpha T3-1 cell line.

The alpha T3-1 cell line which was derived by targeted tumorigenesis in transgenic mice [Windle et al. (1990) Mol. Endocrinol. 4, 597-603] possesses high-affinity binding sites for GnRH analogs coupled to enhanced phosphoinositide turnover and phospholipase D activity. Incubation of alpha T3-1 cells with [D-Trp6]-GnRH analog (GnRH-A) resulted in a rapid increase in gonadotropin alpha-subunit mRNA levels which was detected already at 30 min of incubation (0.1 nM GnRH-A, 3-fold, p < 0.01). The effect diminished with time to reach basal levels at about 12 h of incubation, with a secondary rise in alpha mRNA levels between 12 and 24 h of incubation. Addition of the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA, 100 ng/mL) or the Ca2+ ionophore ionomycin (1 microM) to alpha T3-1 cells also resulted in a rapid increase in alpha-subunit mRNA levels. Surprisingly, GnRH-induced alpha-subunit release was detected only after a lag of 4 h of incubation. Thus, dissociation between exocytosis and gene expression can be demonstrated in GnRH-stimulated alpha T3-1 cell line.

Animals↗
PubMed1992

A double-blind study of the efficacy of metronidazole gel in the treatment of malodorous fungating tumours.

A double-blind placebo-controlled trial was undertaken to assess the value of topical metronidazole gel preparation in the palliation of the offensive odour of fungating tumours. This 5 day trial was followed by a 6 day period during which all patients received the active gel. Subjective odour assessments were performed by both patients and medical staff. 11 patients were entered and the randomisation was then halted because of an obvious overall benefit over the whole 11 days. There was a non-significant trend in favour of the active treatment during the initial double-blind placebo-controlled phase of the trial, and no side-effects were observed.

Administration, Topical↗
PubMed1992

Conservative surgery of renal cell tumors in 140 patients: 21 years of experience.

Operative method, course and complications were analyzed retrospectively in 140 patients who underwent a conservative operation for renal tumor between June 1969 and December 1990. In 53 patients (20 women and 33 men, mean age 61.2 years, range 38 to 77 years, with 49 renal cell carcinomas and 4 benign renal tumors) there was an imperative indication for an organ preserving operation because nephrectomy would have made dialysis obligatory. In 87 patients (29 women and 58 men, mean age 53.7 years, range 27 to 74 years, with 72 renal cell carcinomas and 15 benign renal tumors) the tumor was conservatively resected in the presence of a normal contralateral unit (elective indication) and 68 of these patients (78%) were symptom-free. In the imperative group 32 of 49 patients (65.3%) with renal cell carcinoma had no evidence of disease after a mean followup of 4.6 years. Known metastases were present in 4 of 7 patients who died of the tumors in this group. In 3 patients with an imperative indication for conservative surgery a second tumor occurred in the kidney: 2 were treated with further parenchyma sparing operations, while in 1 with poor physical condition no further measures were possible. Of 72 patients with renal cell carcinoma who underwent an elective operation 68 (94.4%) had no signs of tumor progression after a mean followup of 3.3 years. One patient died of tumor metastases, and 2 (2.7%) had tumor recurrence in the kidney requiring nephrectomy and enucleation, respectively. The 5-year cause-specific survival rates for the imperative and elective groups were 84% and 96%, respectively. Patients with a local stage T3 tumor were characterized by a significantly worse survival curve than those with a stage T1 or T2 tumor but no significant difference was noted among the various grades of differentiation.

Adult↗
PubMed1992

Haematological effects of radioimmunotherapy in cancer patients.

The haematologic effects of radioimmunotherapy (RAIT) in cancer patients have been studied in order to better understand the aetiology of RAIT-associated myelosuppression. Evaluations were performed on patients treated with 131I-anti-carcinoembryonic antigen (CEA) and 131I-LL2, a monoclonal antibody (MAb) reactive with non-Hodgkin's B-cell lymphoma. Both groups of patients experienced decreases in WBC and platelets. Nadirs were observed 42-51 d post first injection in the lymphoma patients, and 49-66 d post first injection (30-43 d post high-dose therapeutic injection) in the carcinoma patients. Within the WBC population, B cells were the most radiosensitive. The evaluations of the binding of these MAbs to peripheral blood cells and the effect of RAIT on lymphocyte subpopulations indicated a drop of 26-92% in the percentage of B lymphocytes within 1 week following treatment with both 131I-LL2 and 131I-anti-CEA MAbs even though only LL2 binds to B cells. The percentage of T lymphocytes was not affected by the 131I-antibody treatments. These observations suggest that the marked drop in circulating B lymphocytes and platelets after the administration of radioiodinated antibodies is a nonspecific radiation effect, and not necessarily related to the binding of MAb to normal B cells. Thus, among WBCs, B cells are uniquely radiosensitive, and will be unusually affected by antibody-directed internal radiation.

Adult↗
PubMed1992

Growth factor-like effects mediated by muscarinic receptors in PC12M1 cells.

Rat pheochromocytoma (PC12) cells stably expressing cloned m1 muscarinic acetylcholine receptors (PC12M1) undergo morphological changes when stimulated by muscarinic agonists. These changes, which include the outgrowth of neurite-like processes, are blocked by the muscarinic antagonist atropine and are not observed in PC12 cells. The observed morphological changes, which are independent of RNA and protein synthesis, are blocked by the methylation inhibitor 5'-deoxy-5'-methylthioadenosine, suggesting that methylation plays a role in this process. Analysis of cyclic AMP accumulation and phosphoinositide turnover reveals that both processes are enhanced on activation by muscarinic agonist. Our data suggest, however, that the muscarinic-dependent neurite-like outgrowth processes are not mediated by cyclic AMP, Ca2+, or protein kinase C pathways. The muscarinic-dependent neurite outgrowth effect is enhanced by nerve growth factor, with a resulting increase in both the number of neurite-extending cells and the length of the neurite. In addition, activation of muscarinic receptors in PC12M1 cells stimulates the induction of marker genes for neuronal differentiation. Muscarinic receptors may therefore mediate growth factor-like effects in these cells.

Adenylyl Cyclases↗
PubMed1992

Cardiovascular responses of patients with cardiac disease to talking and exercise stress testing.

The blood pressure (BP), heart rate (HR), and premature ventricular contraction responses of patients with cardiac disease during talking were compared with those during exercise stress testing (EST). BPs, HR, and heart rhythm were recorded in 52 patients with cardiac disease before and during talking about an intentionally neutral topic and compared with changes during EST. The systolic and diastolic BP and HR increased significantly during talking. Diastolic BP increased significantly more during talking than during EST stages 1 and 2. The increase in diastolic BP during EST stage 3 did not differ from the increase during talking. HR and systolic BP increased more during EST than during talking. Nine patients had premature ventricular contractions during both EST and talking, two during EST only, and one while talking only. The verbalization protocol provides information about changes in diastolic BP that are not seen with EST. It also may be of value for evaluating heart rhythm, HR, and systolic BP changes for patients whose disabilities preclude EST.

Adult↗
PubMed1991

A new murine monoclonal antibody against human hepatoma.

A murine monoclonal antibody (MAb 336) reactive with human hepatocellular carcinoma has been raised after immunizing BALB/c mice with whole HepG2 cells. MAb 336 (IgG1) was reactive with HepG2 (whole cells and membrane fractions), but not normal liver or peripheral blood cells. Immunohistological studies indicated that 12/16 hepatocellular carcinoma and 6/11 cirrhotic livers expressed MAb 336-associated antigen, and most normal human tissues and tissues derived from other cancers were unstained. Direct and competitive binding assays ruled out the possibility that this MAb reacts with alpha-fetoprotein, carcinoembryonic antigen, or ferritin. Western blot analysis indicated that MAb 336 reacts with an antigen of approximately 30,000 daltons. This MAb may be potentially useful for studying antigenic expression in hepatocellular carcinoma and as a targeting agent for radioimmunodetection and immunoconjugate therapy.

Animals↗
PubMed1991

CD5+ B cells and naturally occurring autoantibodies in cancer patients.

We have determined the percentage of CD5+ B lymphocytes in the peripheral blood of cancer patients and healthy controls, using antibodies directed at the CD5 and CD19 (pan-B) markers. The frequencies of CD5+ B cells, expressed as a percentage of total B cells, ranged from 14.3 to 57.5% in the controls and from 14.8 to 82.8% in the patient population. One-third of the cancer patients had frequencies greater than 2 s.d. above the mean of the control population. The CD5+ B cell fraction expressed as a percentage of total lymphocytes was also significantly elevated in this group of cancer patients. These results suggest that the CD5+ B cell compartment may be affected by the malignant process or by the therapy modality employed. The plasma levels of several naturally occurring autoantibodies, the products of the CD5+ B cells, were also assessed in cancer patients and controls. No significant differences were observed when reactivity to several autoantigens was measured. These included nuclear components and phospholipids.

Adolescent↗
PubMed1990

Carcinoembryonic antigen and alpha-fetoprotein expression and monoclonal antibody targeting in a human hepatoma/nude mouse model.

Hep G2, a human hepatocellular carcinoma, was grown s.c. in nude mice, as well as in tissue culture. This line retains the normal liver parenchymal cell capacity to synthesize human plasma proteins such as albumin, but there is no indication that it harbors the hepatitis B virus. We have detected the oncofetal antigens alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) in both Hep G2 xenografts and spent tissue culture media by Ouchterlony double diffusion assays, enzyme-linked immunosorbent assay, and immunohistology. By enzyme-linked immunosorbent assay, the AFP levels were 544.9 ng/ml in the cell culture and 1.6 microgram/g in saline extracts of the xenograft. The CEA levels were 35.2 ng/ml in the cell culture and 5.4 micrograms/g in the xenograft. The biodistribution of a radioiodinated anti-AFP murine monoclonal antibody and an anti-CEA monoclonal antibody were studied separately in nude mice bearing s.c. Hep G2 xenografts in comparison to an isotype-matched irrelevant IgG (Ag8). Anti-CEA antibody showed a preferential localization for Hep G2, but anti-AFP antibody did not. Immunohistochemical studies of the Hep G2 tumor, using biotinylated anti-AFP and anti-CEA, indicate both cytoplasmic and luminal staining of CEA and AFP in the tumor. These results suggest that Hep G2 may be a useful cell line for radioimmunodetection and radioimmunotherapy studies using anti-CEA and possibly anti-AFP monoclonal antibodies.

Animals↗
PubMed1979

Genetic marker for insulin-dependent diabetes mellitus.

A rare genetic type (Bf F1) of properdin factor B is found in 22.6% of patients with insulin-dependent diabetes mellitus but in only 1.9% of the general population, yielding a relative risk of 15.0. This indicates that a genetic locus for insulin-dependent diabetes mellitus is very close on chromosome 6 to Bf, and that Bf F1 is a marker for nearly 1 out of 4 insulin-dependent diabetic patients.

Adult↗
PubMed1979

Detection and partial sequence analysis of gastrin mRNA by using an oligodeoxynucleotide probe.

We have used a specific deoxyoligonucleotide probe to detect gastrin mRNA in poly(A)-enriched RNA preparations from hog antrum. The nucleotide sequence of the oligonucleotide, d(C-T-C-C-T-C-C-A-T-C-C-A), was deduced from the unique amino acid sequence Trp-Met-Glu-Glu of gastrin. When used with hog antral RNA, the dodecanucleotide is an effective primer for the synthesis of gastrin-specific cDNA as judged by nucleotide sequence analysis of cDNA isolated by polyacrylamide gel electrophoresis. We have determined an 81-nucleotide sequence corresponding to the region of the gastrin mRNA that codes for the known amino acid sequence of the G34 progastrin intermediate species, and we have demonstrated the presence of two consecutive basic residues preceding the G34 sequence in the prohormone. Hybridization of gastrin cDNA or synthetic dodecanucleotide to hog antral RNA separated by gel electrophoresis on agarose gels in the presence of methylmercuric hydroxide indicates that the mRNA coding for gastrin is about 620 nucleotides long. These results suggest that the gastrin precursor peptide contains 110-140 amino acids. This method should be of general application for detection and characterization of mRNAs corresponding to proteins of known amino acid sequence.

Animals↗
PubMed1978

Leaking filtering blebs.

Histologic examination of ten leaking filtering blebs revealed an epithelial tract running from the surface of the bleb down to the episclera in eight cases. These epithelial tracts were considered the real cause of the persistent leakage.

Adult↗
PubMed1978

Primary retinal dysplasia transmitted as X-chromosome-linked recessive disorder.

The familial occurrence of retinal dysplasia in five affected male children suggested X-chromosome-linked recessive inheritance. The clinical features were childhood onset, severe visual impairment, head posture, nystagmus, and strabismus. The ophthalmoscopic findings varied in shape and extension; they ranged from retinal folds to dysplastic tissue covering the posterior pole or gliosis with tumor-like protrusion in the vitreous. The marked variability of the retinal findings was paralleled by the visual acuity, which ranged from some vision to blindness. Electroretinograms coordinated well with ophthalmoscopic observations. Of the five mothers, who are the presumed heterozygous carriers, two showed retinal changes.

Blindness↗