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Biomedical subjects

P Ray

Publications and source records attributed to P Ray.

At least 199 records · Page 11Linked to original sources
PubMed1989

Mechanism of agonist-induced down-regulation and subsequent recovery of muscarinic acetylcholine receptors in a clonal neuroblastoma x glioma hybrid cell line.

The mechanisms of carbachol-induced muscarinic acetylcholine receptor (mAChR) down-regulation, and recovery following carbachol withdrawal, were studied in the neuroblastoma x glioma hybrid NG108-15 cell line by specific ligand binding assays. N-[3H]Methylscopolamine ([3H]NMS) and [3H]quinuclidinyl benzilate ([3H]QNB) were used as the ligands for the cell surface and total cellular mAChRs, respectively. Exposure of cells to 1 mM carbachol for 16 h decreased the specific binding of [3H]NMS and [3H]QNB by approximately 80%. Bacitracin (1-4 mg/ml) and methylamine (1-15 mM), inhibitors of transglutaminase and of endocytosis, prevented agonist-induced loss of surface mAChRs. Pretreatment of cells with the antimicrotubular agents nocodazole (0.1-10 microM) and colchicine (1-10 microM) prevented carbachol-induced loss of [3H]QNB binding, but not that of [3H]NMS binding. These results indicate that agonist-induced mAChR down-regulation occurs by endocytosis, followed by microtubular transport of receptors to their intracellular degradation sites. When carbachol was withdrawn from the culture medium following treatment of cells for 16 h, receptors recovered and were incorporated to the surface membrane. This recovery process was antagonized by monovalent ionophores monensin (0.1 microM) and nigericin (40 nM), which interfere with Golgi complex function. Receptor recovery was also prevented by the antimicrotubular agent nocodazole. Thus, recovery of receptors appears to be mediated via Golgi complex and microtubular transport to the surface membrane.

Animals↗
PubMed1989

Cloning, purification, and properties of Candida albicans thymidylate synthase.

The thymidylate synthase (TS) gene was isolated from a genomic Candida albicans library by functional complementation of a Saccharomyces cerevisiae strain deficient in TS. The gene was localized on a 4-kilobase HindIII DNA fragment and was shown to be expressed in a Thy- strain of Escherichia coli. The nucleotide sequence of the TS gene predicted a protein of 315 amino acids with a molecular weight of 36,027. The gene was cloned into a T7 expression vector in E. coli, allowing purification of large amounts of C. albicans TS. It was also purified from a wild-type C. albicans strain. Comparison of several enzyme properties including analysis of amino-terminal amino acid sequences showed the native and cloned C. albicans TS to be the same.

Amino Acid Sequence↗
PubMed1988

Structure-function studies of murine epidermal growth factor: expression and site-directed mutagenesis of epidermal growth factor gene.

Wild-type murine epidermal growth factor (mEGF) and mutants with Leu47 replaced by serine and valine, respectively, have been produced by recombinant DNA methodology. A synthetic gene for mEGF was fused to the coding sequence for the signal peptide of the outer membrane protein A (ompA) of Escherichia coli in the secretion vector pIN-III-ompA3, and the recombinant plasmid was used to transform E. coli. Upon induction of gene expression, mEGF and the mutants was expressed and secreted into the periplasmic space. Purification of the wild-type Leu47-mEGF and the mutants was carried out by reversed-phase and anion-exchange high-performance liquid chromatography (HPLC). Amino acid analysis and Western blot analysis further confirmed the identities of the proteins. Specific activities for wild-type and mutant proteins were measured in both mEGF receptor binding and autophosphorylation assays. The recombinant mEGF has specific activities identical with that of mEGF purified from mouse submaxillary glands, while both mutants have reduced specific activities in both bioassays. The data demonstrate the importance of the highly conserved Leu47 residue in mEGF for full biological activity.

Amino Acid Sequence↗
PubMed1988

Duchenne muscular dystrophy gene expression in normal and diseased human muscle.

A probe for the 5' end of the Duchenne muscular dystrophy (DMD) gene was used to study expression of the gene in normal human muscle, myogenic cell cultures, and muscle from patients with DMD. Expression was found in RNA from normal fetal muscle, adult cardiac and skeletal muscle, and cultured muscle after myoblast fusion. In DMD muscle, expression of this portion of the gene was also revealed by in situ RNA hybridization, particularly in regenerating muscle fibers.

Cells, Cultured↗
PubMed1988

Primary structure of c-kit: relationship with the CSF-1/PDGF receptor kinase family--oncogenic activation of v-kit involves deletion of extracellular domain and C terminus.

The protein kinase domains of v-kit, the oncogene of the acute transforming feline retrovirus HZ4-FeSV (HZ4-feline sarcoma virus), CSF-1R (macrophage colony stimulating factor receptor) and PDGFR (platelet derived growth factor receptor) display extensive homology. Because of the close structural relationship of v-kit, CSF-1R and PDGFR we predicted that c-kit would encode a protein kinase transmembrane receptor (Besmer et al., 1986a; Yarden et al., 1986). We have now determined the primary structure of murine c-kit from a DNA clone isolated from a brain cDNA library. The nucleotide sequence of the c-kit cDNA predicts a 975 amino acid protein product with a calculated mol. wt of 109.001 kd. It contains an N-terminal signal peptide, a transmembrane domain (residues 519-543) and in the C-terminal half the v-kit homologous sequences (residues 558-925). c-kit therefore contains the features which are characteristic of a transmembrane receptor kinase. Comparison of c-kit, CSF-1R and PDGFR revealed a unique structural relationship of these receptor kinases suggesting a common evolutionary origin. The outer cellular domain of c-kit was shown to be related to the immunoglobulin superfamily. The sites of expression of c-kit in normal tissue predict a function in the brain and in hematopoietic cells. N-terminal sequences which include the extracellular domain and the transmembrane domain as well as 50 amino acids from the C-terminus of c-kit are deleted in v-kit. These structural alterations are likely determinants of the oncogenic activation of v-kit.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Prostatic ultrasound in follow-up of prostatic disease.

Longitudinal and radial transrectal prostatic ultrasound techniques were compared for their consistency and reproducibility in recording prostatic size. While the longitudinal image at the 12:00 position was consistent, radial scanning was variable depending on whether the apex, mid, or base aspects of the prostate were scanned. It is recommended that protocols requiring serial measurements of prostate size utilize a longitudinal ultrasonic transducer and scan at the 12:00 position.

Aged↗
PubMed1988

Inferior vena cava thrombosis. Unusual presentation of testicular tumor.

We report an unusual case of testicular tumor presenting as thrombosis of the inferior vena cava. However, in contrast to a previous report, thrombosis in this patient was not caused by compression of the vena cava by neoplasm metastases. In our patient, we postulate that tumor invaded the vena cava and that thrombosis was exacerbated by a hypercoagulable state induced by the tumor.

Adult↗
PubMed1988

Persistent müllerian duct syndrome in a man with transverse testicular ectopia.

A 33-year-old Pakistani man with transverse testicular ectopia underwent surgery for repair of a left inguinal hernia. At operation a uterine structure with attached vasa deferentia was found in the left inguinal area and it was removed. Transverse testicular ectopia has been reported previously in association with the persistent müllerian duct syndrome. A deficiency of activity of a müllerian inhibiting substance during gestation is believed to be responsible for this syndrome. Most patients usually are sterile. Cloning of the gene for a müllerian inhibiting substance should permit studies of the pathogenesis of the persistent müllerian duct syndrome.

Adult↗
PubMed1988

Role of transurethral resection of the prostate in hematogenously disseminated metastasis.

Dissemination of tumor cells by vascular channels seems to be enhanced by certain surgical procedures, e.g. transurethral resection of the prostate, an operative procedure commonly used in the diagnosis and management of prostatic cancer, the third biggest killer of men in the United States. Circulating tumor cells have been the subject of great controversy as they are considered to be the connecting link between the primary tumor and the hematogenously disseminated metastatic growths. Isolation and identification of tumor cells which get released into the vascular channels is somewhat complicated. We report our experience with a technique for isolating and identifying prostatic tumor cells in the circulation and briefly discuss the role of transurethral resection of the prostate in the management of prostatic cancer.

Humans↗
PubMed1987

Inhibition of sensitized leukocyte's in vitro reactivity by circulating immune complexes in prostate cancer.

Circulating immune complexes in the sera of patients with confirmed histological diagnosis of carcinoma of the prostate, were found to interfere in the sensitized leukocyte's in vitro reactivity to prostate cancer associated antigen as evaluated by tube leukocyte adherence inhibition assay, thereby suggesting an inhibitory role of such serum factors in host's anti tumor cell mediated immune responses.

Adenocarcinoma↗
PubMed1987

Lymphocyte subsets in urologic cancer patients.

Peripheral blood T lymphocyte subsets were quantitated by monoclonal antibodies in 91 patients with urologic malignancies as well as eight age-matched controls. In general, the presence of cancer and increasing stage were associated with a relative decrease in helper and an increase in suppressor T-cell activity as well as a decreased T4/T8 cell ratio. Therapy in the form of androgen depletion reversed these trends and restored helper and suppressor levels as well as the T4/T8 ratio to control values. In a small subset of sixteen patients surgery had only modest immediate (prostate) and long term (kidney) effects on these parameters.

Androgens↗
PubMed1987

Benign fibrous ureteral polyps.

Benign fibrous polyps of the ureter are rare. A review of the English literature since 1930 revealed that 71 cases had been described. Three additional cases of fibrous ureteral polyps, one in a ureter with ureteritis cystica, are reported with a discussion of both the histologic findings and proposed treatment plan.

Adult↗
PubMed1987

An evaluation of prostate specific antigen in prostatic cancer.

Prostate specific antigen levels were measured in 118 patients with prostatic cancer and 138 control individuals. Prostate specific antigen was sensitive in detecting prostatic cancer. The levels of prostate specific antigen were elevated in 10 per cent of the patients with stage A, 24 per cent with stage B, 53 per cent with stage C and 92 per cent with stage D disease. However, prostate specific antigen levels also were elevated in 9 per cent of the patients with benign prostatic hypertrophy. This lack of specificity in the presence of benign prostatic hypertrophy probably precludes prostate specific antigen from being recommended as a screening test for prostatic cancer. The ultimate role of prostate specific antigen might be as the marker of choice to monitor therapy for prostatic carcinoma.

Antigens↗
PubMed1987

Molecular heterogeneity of translocations associated with muscular dystrophy.

Individual translocation chromosomes from six girls suffering from Duchenne or Becker muscular dystrophy (DMD or BMD) have been isolated in human-mouse somatic cell hybrids. DNA prepared from these hybrids was probed with sequences physically close to the locus; these include a junction fragment from the site of the X:21 translocation (pXJ1) and subclones from the pERT 87 (DXS164) region which are absent in a minority of male DMD patients. Both sets of sequences mapped within the area defined by the translocation breakpoints, confirming their close proximity to the DMD and BMD loci. Furthermore, the X chromosome breakpoints of the translocations can be divided into three categories depending upon their position in relation to the sequences recognised by pXJ1 and pERT 87. The genomic target disrupted by the translocations examined here is a minimum of 176 kb.

Chromosome Mapping↗
PubMed1987

Replication and packaging of choleraphage phi 149 DNA.

The intercellular replication of the circularly permuted DNA of choleraphage phi 149 involves a concatemeric DNA structure with a size equivalent to six genome lengths. The synthesis of both monomeric and concatemeric DNAs during replication of phi 149 occurred in the cytoplasm. The concatemers served as the substrate for the synthesis of mature phage DNA, which was eventually packaged by a headful mechanism starting from a unique pac site in the concatemeric DNA. Packaging of DNA into phage heads involved binding of concatemeric DNA to the cell membrane. A scheme involving sequential packaging of five headfuls proceeding in the counterclockwise direction from the pac site is proposed. After infection under high-phosphate conditions, the concatemeric DNA intermediates were not formed, although synthesis of monomeric molecules was unaffected.

Bacterial Proteins↗
PubMed1987

An evaluation of five tests to diagnose prostate cancer.

In an effort to determine which of five tests was the most efficient in the diagnosis of prostate cancer, 280 male patients were screened employing aspiration cytology, transrectal ultrasound, acid phosphatase, prostate specific antigen, and the digital rectal examination. The digital rectal examination was the most efficient (75%) and in order of decreasing accuracy were prostate specific antigen (74%), prostatic ultrasound (71%), acid phosphatase (66%), and finally aspiration cytology (63%). In an era when what are more expensive and more technology are assumed to be better, what is simple and traditional is ignored. From an evaluation of these patients it appears that the digital rectal examination still retains its diagnostic efficiency. Finally, in this age of escalating medical costs and physician accountability for these expenses, you can't beat the cost - benefit ratio for the old fashioned rectal exam.

Acid Phosphatase↗