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Biomedical subjects

R Fisher

Publications and source records attributed to R Fisher.

At least 181 records · Page 10Linked to original sources
PubMed1984

Kawasaki syndrome: report of four cases with acute gallbladder hydrops.

We studied gallbladder involvement in 19 patients with Kawasaki syndrome who presented over a 4-year period from 1979 to 1982. Diagnosis and follow-up of gallbladder disease were defined by real-time ultrasound. Complete spontaneous resolution of abdominal symptomatology related to the hydropic gallbladder occurred without complication and did not require surgical intervention. We suggest that the incidence of hydrops of the gallbladder in mucocutaneous lymph node syndrome is higher than commonly appreciated, since diagnosis may be missed unless ultrasound is performed.

Acute Disease↗
PubMed1984

Gastrointestinal angiodysplasia: a possible component of von Willebrand's disease.

Evidence in the literature suggests that von Willebrand's disease constitutes part of a mesenchymal syndrome accompanied by coagulopathy. The cases of two patients with symptomatic intestinal angiodysplasia and concurrent von Willebrand's disease are summarized along with the eight cases previously reported in the literature. All ten cases were in adults ranging in age from 34 to 80 years (average, 58 years). The vascular lesions were located in the stomach or duodenum (four cases), right colon (three cases), and terminal ileum (two cases). One patient had angiodysplasia of the stomach, jejunum, and sigmoid colon. While the prevalence is unknown, these ten cases linking gastrointestinal angiodysplasia with von Willebrand's disease appear to reflect an association greater than more coincidence. Coagulation testing, including determination of template bleeding time and partial thromboplastin time, should probably be performed in all patients bleeding from gastrointestinal angiodysplasia to screen for von Willebrand's disease.

Adult↗
PubMed1984

Small intestinal angiodysplasia in the elderly.

The predominant site of bleeding intestinal angiodysplasia in elderly patients will be the cecum or ascending colon, but recent experience in the Yale-Affiliated Gastroenterology Program in 1 year indicates that elderly patients may have bleeding acquired angiodysplasia (AD) confined to the small intestine only. A review of the literature confirms that symptomatic small intestinal AD is infrequent and occurs at an average age of 32 years in some series. Five patients with symptomatic small intestinal AD diagnosed during 1981 at Yale were older, with an average of 62 years. Three of the five cases (all female) had lesions in the duodenum, with two (males) having lesions in the ileum. Noncolonic AD in the elderly may be acquired during life, as in the classic situation in the right colon, but may be difficult to distinguish clinically and pathologically from the vascular lesions of hereditary hemorrhagic telangiectasia.

Adult↗
PubMed1983

A complementary DNA oligomer releases a transcription pause complex.

The formation of alternative secondary structures in the transcript of the tryptophan (trp) operon leader region regulates expression of the trp operons of Escherichia coli and other bacterial species. During in vitro transcription RNA polymerase pauses near base pair 90 after the first hairpin secondary structure in E. coli trp leader mRNA is formed. The E. coli L-factor enhances transcription pausing at this site (Farnham, P. J., Greenblatt, J., and Platt, T. (1982) Cell 29, 945-951); presumably it does so by facilitating recognition of the RNA hairpin by polymerase. We show that addition of a DNA oligomer complementary to the proximal segment of the RNA hairpin relieves transcription pausing in vitro both in the presence and absence of L-factor. The oligomer apparently interferes with formation of the RNA hairpin which we believe is recognized by polymerase as the pause signal. The oligomer also relieves pausing in L-factor-induced paused complexes, suggesting that the oligomer can disrupt a preformed secondary structure in the transcript.

DNA↗
PubMed1983

Characteristics of nicotinamide and N1-methylnicotinamide protection from alloxan diabetes in mice.

Comparisons were made of the dose-response and time-course characteristics of nicotinamide (NIC) and its metabolite, N1-methylnicotinamide (MNIC), protection from alloxan-induced diabetes in mice. A significant reduction in the permanent hyperglycemia caused by alloxan (50 mg/kg, iv) was observed when NIC or MNIC was given iv at a dose of 800 mg/kg 2 hr before alloxan. Complete protection was provided by pretreatment with 1200 mg/kg of either agent. There was a linear increase in 2-hr serum levels of NIC or MNIC after increasing doses of each protective agent. Protection after a 1200 mg/kg dose of NIC was of a shorter duration (6 hr) than after a corresponding dose of MNIC (greater than 24 hr). This longer protective action of the metabolite was accompanied by correspondingly higher serum levels of MNIC when compared to levels of NIC after an identical dose. No protective effects of NIC or MNIC were apparent when the agents were added to isolated mouse pancreatic islets prior to alloxan exposure in vitro. The results indicate that both NIC and its metabolite, when given in high doses before alloxan, are capable of protecting mice from alloxan diabetes. The protective action of NIC and MNIC appears to be an indirect one because the agents were ineffective as protectants in an in vitro system.

Alloxan↗
PubMed1983

Voiding dysfunction in institutionalized elderly men: the influence of previous prostatectomy.

Voiding problems, either retention or incontinence, affect a majority of institutionalized elderly patients. Although impaired cerebral function is the dominant cause, those patients who had undergone prior transurethral prostatectomy were more vulnerable to the development of voiding dysfunction than those who had not. Moreover, the elimination of obstruction by prostatectomy did not produce the expected shift from indwelling catheterization to condom drainage.

Aged↗
PubMed1983

An open dose finding study of melperone in treatment of agitation and irritability associated with dementia.

Seventeen older patients with a diagnosis of Organic Brain Syndrome were placed on a four-week trial of melperone for treatment of behavioural disturbances associated with dementia. Efficacy evaluation of the drug revealed improved ratings of the patients in the areas of agitation/irritability, anxiety, unsociability, and mental alertness. Thirteen of the fourteen patients who completed the trial were rated generally as showing at least minimal improvement while on the drug. There were no serious side effects noted, with drowsiness the most frequent finding. These favourable results are suggestive of the usefulness of this drug, and point to the need for double-blind, comparative studies.

Aged↗
PubMed1983

Depressive illness as a presentation of primary lymphoma of the central nervous system.

A 65-year-old man was referred from a medical unit for psychiatric assessment of a depressive illness associated with intermittent vomiting. No organic disorder was identifiable after the initial clinical examination and extensive investigations. A primary lymphoma involving the limbic system was eventually detected on repeat CAT scan and was confirmed at autopsy. This tumour, which is increasing in incidence, is notoriously difficult to diagnose and frequently presents with combined psychological and organic symptoms. It may be radiosensitive if detected early enough.

Aged↗
PubMed1982

Analysis of RNA polymerase by trypsin cleavage. Different structural changes produced by heparin and DNA.

Alterations in RNA polymerase structure can be detected using initial trypsin cleavage rates as a conformational probe. Both template (poly[d(A-T) . d(A-T)] and the RNA polymerase inhibitor, heparin, alter the rates at which the subunits of the enzyme are cleaved. However, while the presence of poly[d(A-T) . d(A-T)] slows the cleavage of subunits beta, sigma, and alpha by trypsin, heparin accelerates the cleavage of beta and sigma. Furthermore, the presence of heparin does not prevent the effect of poly[d(A-T) . d(A-T)] on the beta and sigma cleavage rates. Thus, heparin does not eliminate the interaction between DNA and RNA polymerase. That heparin does alter the nature of this interaction is demonstrated by the fact that template decreases the trypsin cleavage rate of subunit alpha in the absence, but not in the presence, of heparin. Like heparin, the addition of RNA to the reaction increases the accessibility of beta and sigma to trypsin. Hence the interaction of heparin with RNA polymerase may mimic the product, rather than the template, interaction.

DNA-Directed RNA Polymerases↗
PubMed1982

K+-evoked [3H]-5-HT release from rat frontal cortex slices: the effect of 5-HT agonists and antagonists.

The pharmacological characteristics of a pre-junctional 5-HT autoreceptor have been studied by following the Ca2+-dependent, K+-evoked release of [3H]-5-HT from preloaded rat frontal cortex slices. Added 5-HT, in the presence of the 5-HT uptake inhibitor chlorimipramine, caused a dose related inhibition of the K+-evoked release of [3H]-5-HT in this system as did the 5-HT analogues 5-methoxytryptamine, N-methyltryptamine, 5-methoxy-NN'-dimethyltryptamine, N-methyl 5-hydroxytryptamine and tryptamine. The inhibitory effect of 1 microM 5-HT on the K+-evoked release of [3H]-5-HT was reversed in a dose-related manner by the 5-HT antagonist drug, methiothepin (pA10 value 6.7). At a concentration of 1 microM, the 5-HT antagonists drugs cinanserin and mianserin produced a small but significant reversal of the 5-HT induced inhibition of K+-evoked [3H]-5-HT release, but methysergide, metergoline and cyproheptadine were completely without effect at this concentration. The results are interpreted as evidence for a pre-junctional autoreceptor for 5-HT in the frontal cortex of the rat with a different pharmacological specificity for 5-HT antagonists from previously studied 5-HT receptors.

Animals↗
PubMed1982

Factors influencing hepatic glutathione concentrations: a study in surgical patients.

1. Hepatic total glutathione (reduced plus oxidized) and oxidized glutathione levels were measured in operative wedge liver biopsy specimens obtained from 70 patients. 2. The effects on hepatic reduced glutathione (GSH) level of four potential risk factors (abnormal liver histology, abnormal preoperative tests fo liver function, drug ingestion and protein malnutrition) were examined. 3. Each of the four risk factors was associated with a significant reduction in hepatic GSH. Multivariate analysis indicated that only three of these risk factors (abnormal liver histology, drug ingestion and protein malnutrition) had independent effects in reducing hepatic GSH. 4. Twenty-five of the 70 patients studied did not have any of the four risk factors. The mean hepatic GSH level in these patients was 3.92 mumol/g of liver wet weight (SD 0.62), giving a 95% reference range of 2.71-5.14 mumol/g of liver net weight.

Adolescent↗
PubMed1982

An interaction between gramicidin and the sigma subunit of RNA polymerase.

Gramicidin, a peptide antibiotic produced by Bacillus brevis, inhibits initiation of transcription by RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6). We show here that the presence of gramicidin causes an increase in the rate of cleavage of the sigma subunit of Escherichia coli RNA polymerase by trypsin, although it does not alter the cleavage rate of any of the core subunits. Furthermore, whereas isolated sigma is cleaved much faster than is sigma in holoenzyme, gramicidin substantially decreases the trypsin cleavage rate of isolated sigma. Inhibition of RNA polymerase activity by gramicidin in consistent with a sigma-specific effect: the antibiotic is a strong inhibitor of transcription of T7 phage DNA, which requires sigma for activity, but it has little effect on transcription of sigma-independent templates, such as poly(dA-dT).poly)dA-dT) and calf thymus DNA. These results are discussed in light of the hypothesized role for gramicidin in the initiation of sporulation of B. brevis.

DNA, Viral↗
PubMed1982

Intergroup Hodgkin's disease in children study of stages I and II: a preliminary report.

The intergroup study of involved-field (IF) radiotherapy, IF radiotherapy plus MOPP chemotherapy, and extended-field (EF) radiotherapy for treatment of Hodgkin's disease in children has assessed 305 patients. Of these, 279 were "not ineligible" (no mediate cause for disqualification). Among 223 randomized patients, 144 were evaluable, 131 had documentation of complete or partial remission, 20 of the remitters relapsed, and two died. Among 62 nonrandomized patients with favorable presentations (unilateral upper neck, unilateral inguinal, or massive mediastinal disease), 29 had documented remission, two relapsed, and none died. Length of initial disease control (LIDC) was used to measure duration of response. LIDC was best in patients given IF plus MOPP, and 95% are disease free. EF was better than IF radiotherapy (P = 0.004). Of the disease characteristics prognostic for response (stage, histologic subtype, and presence of symptoms), only the last factor had a statistically significant effect on LIDC (P = 0.004). Ninety-six percent of the patients survive. Using criteria developed by the committee, 23% of the staging procedures reviewed were nonevaluable and 28% of the radiotherapy treatments were nonevaluable. The necessity for criteria for evaluation of staging and treatment is certain. Length of followup is too short for correlations of treatment with significant late effects and for relevant therapeutic recommendations.

Antineoplastic Agents↗
PubMed1981

A cloned cyanobacterial gene for glutamine synthetase functions in Escherichia coli, but the enzyme is not adenylylated.

The coding sequence for Anabaena 7120 glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.1] are shown to be contained within a 7.5-kilobase-pair (kbp) HindIII fragment that has been cloned by plaque hybridization. The hybridization probe for the cyanobacterial gene was a recombinant plasmid containing the glnA gene from Escherichia coli K-12. Evidence that the cloned Anabaena fragment contains the glnA gene includes complementation of a glnA deletion mutant of E. coli and immunological identity of the enzyme produced by the cloned Anabaena fragment in E. coli with glutamine synthetase purified from Anabaena 7120. Heteroduplex analysis reveals 0.65 kbp of homology between the 7.5-kbp Anabaena 7120 fragment and an 11-kbp E. coli fragment that codes for E. coli glutamine synthetase. Studies of Anabaena glnA gene activity in E. coli suggest that the cyanobacterial gene is not repressible and that the Anabaena 7120 glutamine synthetase is not adenylylated in E. coli.

Adenosine Monophosphate↗