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Biomedical subjects

M Robinson

Publications and source records attributed to M Robinson.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of growth and gene expression in human papillomavirus-transformed keratinocytes by transforming growth factor-beta: implications for the control of papillomavirus infection.

Cervical carcinogenesis is a multistep process that appears to be initiated by infection of squamous epithelial cells in the cervix with one of a limited number of human papillomavirus (HPV) types. However, the mechanisms involved in the evolution of benign, HPV-induced lesions to malignancy have not yet been fully elucidated. Transforming growth factor-beta (TGF-beta), a multifunctional growth factor produced by cells in the skin, inhibits the proliferation of foreskin and cervical keratinocytes in vitro. We examined the effects of TGF-beta on growth and virus early-gene expression in cell lines immortalized by two HPV types associated with cervical carcinogenesis as well as the expression of TGF-beta 1 mRNA transcripts in normal and HPV-positive cells in vivo and in vitro. We found that normal and HPV-positive cells expressed similar levels of TGF-beta 1 mRNAs and exhibited similar patterns of responsiveness to three isoforms of TGF-beta in both monolayer and modified organotypic cultures. Of particular interest is our finding that the expression of the E6 and E7 early viral transforming regions of both HPV16 and HPV18 was reversibly and rapidly inhibited by TGF-beta. In one HPV16-positive cell line examined in detail, inhibition of HPV expression required protein synthesis and occurred at the level of transcription. HPV-immortalized cells selected for resistance to in vitro differentiation signals remained sensitive to TGF-beta-mediated growth inhibition. These results, showing that both growth and virus gene expression in HPV-transformed cells were responsive to TGF-beta, suggest that endogenous growth factors produced by different cell types in squamous epithelium may play a role in the progression of cervical neoplasia.

Blotting, Northern↗
PubMed1992

p53, c-erbB-2 and the epidermal growth factor receptor in the benign and malignant prostate.

Expression of the p53, the epidermal growth factor receptor (c-erbB-1) and c-erbB-2 protein was studied in 34 men with benign prostatic hyperplasia and 29 men with locally advanced prostate cancer by means of an immuno-histochemical method. Strong staining for p53 was found in five of 29 prostate cancers (17%; mean 21% +/- 7% of malignant cells stained in the positive tumours), but no staining was found in benign prostatic hyperplasia (p less than 0.05). On the other hand, the epithelium in benign glands was stained positively for c-erbB-2 in 18% (6/34) and for the epidermal growth factor receptor in 88% (30/34); whereas malignant epithelium stained strongly for c-erbB-2 in 21% (6/29) and for the epidermal growth factor receptor in only 17% (5/29). Prostate cancer was associated with a significant decrease in epidermal growth factor receptor staining (p less than 0.0001) and a significant increase in p53 staining (p less than 0.05). Most of the tumours were advanced and no significant relationship was observed between tumour stage and grade and expression of p53, the epidermal growth factor receptor or c-erbB-2. These findings demonstrate that altered expression of the epidermal growth factor receptor and p53 protein occurs in prostate cancer, but were not associated with other features of prognostic importance such as stage or grade.

Aged↗
PubMed1992

Intra-arterial adriamycin, conventionally fractionated radiotherapy and conservative surgery for soft tissue sarcomas.

Thirteen patients with soft tissue sarcomas were treated with a combination of intra-arterial Adriamycin, conventionally fractionated radiotherapy (2 Gy per day), and conservative surgery (trimodal therapy). Severe acute complications occurred in 10 patients: 3 brachial artery thromboses, 6 delayed wound healing, 4 wound infections, and 3 cases of necrosis of the skin plus subcutaneous tissues. Three patients have developed local recurrence. Five patients are alive, 4 of whom are disease-free, and the median follow up time of surviving patients is 56 months. One has significant impairment of limb function due to joint ankylosis. An additional 2 patients were treated with intra-arterial Adriamycin and conservative surgery for local recurrence after previous surgery and radiotherapy; both died of subsequent metastatic disease, one having a further local recurrence. One patient with multifocal angiosarcoma was treated with intra-arterial Adriamycin and radiotherapy but no surgery, and is alive free of disease 49 months later. The combination of radiotherapy and intra-arterial Adriamycin with surgery resulted in significant acute toxicity. This small study has not demonstrated any improvement in local control compared with that expected with conservative surgery and radiotherapy alone.

Adult↗
PubMed1992

Single pass sequencing and physical and genetic mapping of human brain cDNAs.

We have performed single pass sequencing of 1,024 human brain cDNAs, over 900 of which seem to represent new human genes. Library prescreening with total brain cDNA significantly reduced repeated sequencing of highly represented cDNAs. A subset of sequenced cDNAs were physically mapped to their chromosomal locations using gene-specific STS primers derived from 3' untranslated regions. We have also determined that human brain cDNAs represent a rich source of gene-associated polymorphic markers. Microsatellite-containing cDNAs can be physically mapped and converted to highly informative genetic markers, thus facilitating integration of the human physical, expression and genetic maps.

Base Sequence↗
PubMed1992

Ranitidine for erosive oesophagitis: a double-blind, placebo-controlled study. Glaxo Erosive Esophagitis Study Group.

A multicentre, randomized, double-blind, placebo-controlled study was conducted to evaluate the efficacy and safety of ranitidine 150 mg and 300 mg in 342 patients with erosive oesophagitis. Treatment was given four times daily, and continued for 12 weeks or until healing (that is, normal or only erythematous mucosa). Erosive oesophagitis healing rates, as determined by endoscopy, were significantly greater in ranitidine-treated patients by 4 weeks compared with those of placebo-treated patients. By 12 weeks, erosive oesophagitis healing rates were 83 and 81% for ranitidine-treated patients (150 and 300 mg, respectively) and 58% for placebo-treated patients (P less than or equal to 0.001, ranitidine vs. placebo). Symptomatic relief was achieved within 24 hours after starting either dosage of ranitidine. Heartburn frequency (P less than 0.001) and severity (P less than 0.001), as well as antacid consumed per week (P less than 0.001), were reduced in both ranitidine groups in comparison with placebo. Healing rates and symptom relief were similar in the two ranitidine groups. Both dosages of ranitidine were well tolerated. Ranitidine (150 mg) given four times daily appears to be as effective as 300 mg ranitidine given four times daily in patients with moderate to severe oesophageal erosions.

Adult↗
PubMed1992

P53 and Ki-67 immunoreactivity in human prostate cancer and benign hyperplasia.

Mutation of the p53 gene is one of the commonest genetic abnormalities found in solid human tumours. This gene is probably concerned with the control of cellular proliferation and in view of this we carried out a study of human prostate cancer and benign prostatic hyperplasia, comparing the expression of mutated p53 with measurement of growth fractions as assessed by staining with Ki-67. A series of 29 patients with prostate cancer (CaP) were compared with 34 men with benign hyperplasia (BPH); 22 of 29 prostate cancers (76%) contained Ki-67 immunoreactivity compared with 10 of 34 (29%) BPH. With respect to p53 staining, significantly more prostate cancers (17%) were stained than BPH (0%). The mean Ki-67 score in cancers positive for p53 (4.3%) was greater than that found in cancers negative for p53 (1.2%), but no statistically significant relationship was found between tumour grade and Ki-67 staining. The use of Ki-67 and p53 staining may allow identification of tumours with a higher rate of cell growth and may permit development of prognostic factors.

Aged↗
PubMed1992

Estimation of erythropoietin secretion rate in normal and uremic subjects.

We have developed a method for directly estimating the secretion rate of endogenous erythropoietin (EPO) in human subjects. Carrier-free recombinant human EPO was labeled with 125I by the chloramine T method. Human serum albumin was then added prior to removal of free iodide. Seven normal subjects and nine patients with chronic uremia and anemia were studied. Each subject received a bolus of 125I-EPO according to body size and then a constant infusion for 5 h. Secretion rate was calculated as the rate of infusion divided by serum EPO specific activity given by the protein-bound counts divided by the EPO concentration. Serum EPO concentration was significantly higher in the patients than the controls (mean 30.9 pg/ml vs. 11.1 pg/ml, P < 0.05), although all values were within the normal range. Mean EPO secretion rate was 255 in the patients (range 68-1,101) and 190 pg.kg-1 x h-1 in the normal group (range 52-382). This difference was not significant. As the subjects were in a steady state, EPO disappearance/degradation was the same in patients compared with controls despite a relatively hypoplastic marrow.

Adult↗
PubMed1992

Ninety-day toxicity study of chloral hydrate in the Sprague-Dawley rat.

Male and female Sprague-Dawley rats were administered drinking water containing 300, 600, 1200, or 2400 mg/L chloral hydrate for 90 days. A control group received distilled water only. No animals died during the study and no differences were observed in body weight gain or food and water consumption, except for males at the highest-dose level. Minor treatment-related effects were observed for organ weights and hematological parameters and these did not appear to be of toxicological significance. Some indications of toxicity were evident in the 2400 mg/L male group (equivalent to 168 mg/kg-day) including a significant decrease in food and water consumption and in weight gain. In addition, histopathological examination of these animals revealed an apparent increase in the incidence of focal hepatocellular necrosis. Increases in AST, ALT, and LDH, which occurred at several dose levels in males, but particularly at 200 mg/L, are consistent with the hepatocellular necrosis of minimal to mild severity diagnosed by microscopic examination. These liver changes, except for sporadic enzyme changes, were not seen in the female rats which actually consumed higher doses of chloral hydrate (e.g., 288 mg/kg-day at 2400 mg/L). On the basis of the mild liver toxicity (histopathological and clinical) observed in males at the highest doses (168 mg/kg-day), the no observed adverse effect level (NOAEL) for oral exposure of rats to chloral hydrate for 90 days is considered to be 96 mg/kg-day (600 mg/L).

Alanine Transaminase↗
PubMed1992

Manometry during food ingestion aids in the diagnosis of diffuse esophageal spasm.

It has been shown that food ingestion can provoke esophageal motor abnormalities in patients with otherwise normal manometry. Such motor abnormalities are usually nonspecific in character. We now report water swallow and food ingestion data on 12 patients with a history of dysphagia and/or chest pain who satisfied strict manometric diagnostic requirements for diffuse esophageal spasm. Three of these patients had normal water swallow manometry, yet, during food ingestion, showed manometric evidence of diffuse esophageal spasm. In the other nine patients, the occurrence of nonperistaltic contractions was greater, and there was a greater incidence of nonperistaltic contractions of 100 mm Hg or more after ingestion of food. We conclude that food ingestion increases the diagnostic yield of manometric testing for diffuse esophageal spasm and, not infrequently, magnifies an abnormality seen during standard water-swallow testing.

Adult↗
PubMed1991

A method for the simultaneous determination of alkylacylglycerol, diacylglycerol, monoalkylglycerol, monoacylglycerol, and cholesterol by high-performance liquid chromatography.

We describe a method for the quantitative analysis of the individual subclasses (1-O-alkyl and 1-acyl) of diradylglycerols and monoradylglycerols. These lipids, along with cholesterol, were separated from other neutral and polar lipids on silica columns and analyzed by normal-phase high-performance liquid chromatography (HPLC) as their benzoate derivatives. Cholesterylbenzoate, alkylacylglycerolbenzoate, diacylglycerolbenzoate, monoalkylglyceroldibenzoate, and monoacylglyceroldibenzoate eluted from HPLC in five distinct zones. The derivatives of diradylglycerols and monoradylglycerols were further separated within each discrete zone on the basis of the total number of aliphatic carbons at the sn-1 and sn-2 positions. Radiolabeled cholesterol and dihexadecanoylglycerol were used to monitor recovery. Amounts of synthetic alkylacylglycerol, diacylglycerol, monoalkylglycerol, and monoacylglycerol as low as 0.2 nmol per subclass could be accurately quantified. The technique was used to determine the content of diradylglycerol and monoradylglycerol subclasses in Madin-Darby canine kidney and CFTL-12 mast cells. This method should prove useful for the quantitation of lipid second messengers in cultured cells.

Animals↗
PubMed1991

Effects of intracisternal endothelin-1 injection on blood flow to the lower brain stem.

The central effects of endothelin-1 (Et-1, 10-30 pmol in 2.5 microliters injected intracisternally) have been investigated in the conscious rat. With 10 and 20 pmol Et-1, no significant change in blood pressure was observed. With 30 pmol Et-1, mean arterial blood pressure rose by 40 +/- 10 mm Hg with an accompanying modest, short-lived bradycardia at 2 min post-injection. Cerebral blood flow [( 14C]iodoantipyrine autoradiography), measured simultaneously with the hypertensive response, was markedly reduced throughout the caudal medulla and cerebellum (by up to 85%), while significant hyperaemia was evident in a number of forebrain structures (e.g. an increase of 78% in sensorimotor cortex). These observations have relevance to two distinct scientific areas. Concerning the significant effect of Et-1 in central cardiovascular control, these results caution against drawing conclusions from ventricular application with knowledge only of cardiovascular parameters. These results also illustrate the profound effects of Et-1 which is uniquely capable of overriding cerebral autoregulatory mechanisms.

Animals↗
PubMed1991

A novel gamma subunit of the GABAA receptor identified using the polymerase chain reaction.

We have utilized a polymerase chain reaction (PCR) strategy to identify a novel subunit, gamma 3, of the GABAA receptor. The gamma 3 cDNA encodes a mature protein of 450 amino acids that contains structural features typically conserved among subunits of the GABAA receptor family. The gamma 3 subunit shares approximately 66% sequence identity with the gamma 2 subunit but only 38% and 29% with alpha 1 and beta 1 subunits, respectively. Localization of the gamma 3 mRNA indicates that it is widely distributed throughout the mouse brain in a pattern similar to that observed for mRNAs encoding the gamma 2 subunits.

Amino Acid Sequence↗
PubMed1991

High dose hyperfractionated radiotherapy in the treatment of extremity soft tissue sarcomas.

A hyperfractionated radiotherapy schedule has been evaluated in the treatment of 29 adults with limb or limb girdle soft tissue sarcomas. The objective was to increase the total administered dose and possibly improve local control, without increasing late normal tissue damage. Twice daily 1.25 Gy fractions (with a minimum interval of 6 h) have been given over 5 to 6 weeks to 12 patients pre-operatively, 10 post-operatively and 7 palliatively. Five patients received 62.5 Gy in 5 weeks pre-operatively and 3 palliatively. Nineteen of the remaining 21 patients received 75 Gy in 6 weeks with a field size reduction after 5 weeks. Sixteen of 29 tumours were situated in the thigh and only 2 were in the upper limb. Twenty were of high grade. The mean tumour size of those treated radically was 13.1 cm (range 5 to 40 cm). Sixteen patients (76%) given 75 Gy developed moderate or severe skin erythema maximal at 5 weeks. Despite the large field sizes used (mean phase one of 34.5 cm, and phase two of 22.8 cm) only 2 patients failed to complete the planned treatment because of the severity of these reactions. Two other patients developed partial wound breakdowns after the end of treatment--both healing spontaneously. Fourteen patients developed an area of moist desquamation--11 mild, 2 moderate and one severe. There have been four late wound breakdowns requiring surgical intervention; all have since healed well. The median follow up is short at 556 days. Ten of 19 evaluable patients have developed moderate/severe induration, 5/19 mild and 4/19 none.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗