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Biomedical subjects

G Morris

Publications and source records attributed to G Morris.

At least 73 records · Page 4Linked to original sources
PubMed1991

Cysteine proteinase inhibitors and bleomycin-sensitive and -resistant cells.

We have isolated a new human head and neck carcinoma cell line (C-10E) that is highly resistant to BLM (40-fold) when compared to the parental (A-253) cell line. Consonant with BLM resistance in the C-10E cell line, we found that this cell line accumulated 2- to 3-fold less BLM A2 than A-253 cells. Kinetic analyses of BLM A2 association revealed a decreased Vmax for C-10E cells with little change in Ka. Furthermore, the BLM-resistant cell line (C-10E) metabolized BLM A2 to a greater extent than its sensitive counterpart (A-253). Thus, compared to A-253 cells, the C-10E cells exhibited both decreased cellular association and increased metabolism of BLM. Synergistic cytotoxicity was seen when BLM was combined with either E-64 or leupeptin, cysteine proteinase inhibitors known to block BLM metabolism in vitro. E-64 inhibited the metabolism of BLM A2 in both C-10E and A-253 cells, and cellular accumulation of radiolabeled BLM A2 was increased by leupeptin or E-64 in only A-253 cells. These results suggest that both inhibition of drug metabolism and increased drug accumulation contribute to this synergism.

Bleomycin↗
PubMed1991

The cholinergic regulation of potassium (86Rb+) permeability in sweat glands isolated from patients with cystic fibrosis.

Sweat glands isolated from skin obtained from normal subjects and patients with cystic fibrosis (CF) were pre-loaded with 86Rb+ and superfused with a physiological salt solution and the rate of 86Rb+ efflux was measured as an indicator of cellular potassium permeability. Acetylcholine always evoked a permeability increase in the glands from control subjects and this response could be resolved into calcium-dependent and calcium-independent components. Sweat glands from CF patients did not show such consistent responses. In three individuals the glands were abnormally insensitive to acetylcholine but normal responsiveness was seen in a fourth case. It is proposed that CF can induce dysfunction of calcium-dependent control processes in sweat glands.

Acetylcholine↗
PubMed1991

Isolation of amoebae and Pseudomonas and Legionella spp. from eyewash stations.

Forty eyewash units were sampled for protozoa, bacteria, and fungi. Total heterotrophic bacterial counts on nutrient agar and R2A agar (Difco Laboratories, Detroit, Mich.) ranged from 0 to 10(5) CFU/ml, with Pseudomonas spp. being the most frequently isolated. Total counts of 10(4) and 10(8) cells per ml were obtained with the acridine orange staining procedure. All samples were examined for Legionella spp. by direct fluorescent-antibody staining and by culturing on buffered charcoal-yeast extract agar containing alpha-ketoglutarate and glycine and supplemented with cycloheximide, vancomycin, and polymyxin B. DNA-DNA hybridization was used to confirm identification of the Legionella isolates. Legionellae were detected in 35 of 40 (87.5%) samples by direct fluorescent-antibody staining, with 3 samples yielding both Legionella spp. and amoebae. Amoebae identified as Hartmannella, Vahlkampfia, Acanthamoeba, and Cochliopodium spp. were detected in 19 of 40 (47:5%) samples. Sabouraud dextrose agar was used to obtain a crude estimate of viable fungal populations, pH, hardness, and ammonia, alkalinity, chlorine, copper, and iron contents were recorded for all water samples collected from eyewash stations; 33% of the samples had greater than or equal to 10 mg of CO2 per liter. It is concluded that eyewash stations not regularly flushed and/or cleaned and used to flush traumatized eye tissue may be a source of infection and can contaminate laboratory environments via aerosol transmission.

Amoeba↗
PubMed1991

Familial cardiac amyloidosis. Diagnosis by immunocytochemistry.

Familial cardiac amyloidosis is a rare disorder that is difficult to diagnose. There is no specific therapy for this disease, but it is important to distinguish the cardiac and gastrointestinal symptoms of this disease from those of other treatable causes. We have treated a patient with this disorder who presented with cardiac and gastrointestinal symptoms. The diagnosis of amyloidosis was suspected on rectal biopsy and was confirmed by immunocytochemistry and immunoalkaline phosphatase technique. Pre-albumin was demonstrated in the lesion. We concluded that when familial amyloidosis is suspected, a biopsy from the suspected organ system is helpful for the diagnosis. The detection of pre-albumin by immunocytochemistry can elucidate the diagnosis of familial amyloidosis.

Aged↗
PubMed1990

The haplotype distribution of the delta F508 mutation in cystic fibrosis families in Scotland.

The gene defective in cystic fibrosis (CF) has recently been isolated and the major mutation identified. The haplotype distribution of this mutation (delta F508) has been determined for 215 CF chromosomes in the Scottish population. delta F508 represents 73% of all CF mutations in this group. There remains considerable linkage disequilibrium between XV2c and KM19 and other mutations in the CF gene.

Chromosome Deletion↗
PubMed1990

Acalculous cholecystitis due to Salmonella virchow.

We report a case of systemic infection with Salmonella virchow in a 21-year-old male who subsequently developed acalculous cholecystitis. His symptoms and signs-resolved with parenteral antibiotics, as did the ultrasonographic findings in the gall bladder. To our knowledge, this is the first reported case of acalculous cholecystitis due to this serotype.

Acute Disease↗
PubMed1988

Novel modes of action of aminoglycoside antibiotics against Pseudomonas aeruginosa.

Several mucoid strains and one non-mucoid strain of Pseudomonas aeruginosa were grown in subinhibitory concentrations of various aminoglycosides, beta-lactams, and ciprofloxacin. At antibiotic concentrations that did not affect bacterial growth, aminoglycosides inhibited the excretion of alginate capsule and the production of the iron-chelating siderophores. The same concentrations also disturbed other aspects of the bacterium's iron metabolism, manifested by reduced cellular levels of cytochromes and catalase. beta-lactams, except for cefotaxime, and ciprofloxacin did not reduce alginate excretion. These effects on virulence factors are likely to contribute to the efficacy of aminoglycosides.

Alginates↗
PubMed1988

Acquired common variable hypogammaglobulinaemia and lymphoedema.

Two patients with lymphoedema of the legs developed recurrent respiratory infections and were found to have panhypogammaglobulinaemia. The early recognition and treatment of this form of immunity deficiency in patients with lymphoedema is important in order to prevent recurrent infections which could cause pulmonary damage and further lymphatic stasis.

Adult↗
PubMed1988

Susceptibility of anaerobic bacteria to antimicrobial agents.

The antimicrobial susceptibility of 1,117 clinical isolates of anaerobic bacteria was determined by the agar dilution technique. Metronidazole was the most active agent; only Propionibacterium acnes and Actinomyces sp. isolates were resistant. Clindamycin and chloramphenical were the next most effective agents. Beta-lactam antibiotics, with the exception of penicillin, were active against most anaerobes other than the Bacteroides fragilis group. At a breakpoint of 8 mg/l, 25% of Fusobacterium spp. and 30% of the non-fragilis Bacteroides spp. were resistant to penicillin. The highest resistance to beta-lactams was seen in the B. fragilis group. Within the indole-positive members of the group, resistance rates of 71% were seen for cefoxitin, 49% for moxalactam, 79% for cefotaxime, 22% for piperacillin and 89% for penicillin. We conclude that metronidazole has the most predictable in vitro activity against common clinical anaerobic isolates and that resistance to beta-lactams was frequent and of potential clinical importance as these latter agents are frequently used in the prophylaxis and therapy of mixed anaerobic infections.

Anti-Bacterial Agents↗
PubMed1988

An evaluation of a rapid latex test for the diagnosis of Clostridium difficile-associated diarrhea.

We present here the results of an evaluation of a rapid latex test for detection of Cl. stridium difficile-associated in comparison with our standard cytotoxin assay and culture for C. difficile. Some 515 diarrheal stools were examined. C. difficile was cultured from 70 specimens (13.5%); 53 specimens (10.2%) were positive with the latex test, and 50 (9.6%) by cytotoxin assay. The latex test did not differ significantly from the cytotoxin assay in sensitivity or specificity compared to culture results. There was also no significant difference in the specificity of the latex test compared to cytotoxin assay in patients in whom the diagnosis of C. difficile-associated diarrhea was negative. Positive and negative predictive values of the latex test for C. difficile-associated diarrhea were similar to those of cytotoxin assay. The latex test thus appears to be a rapid and practical test for the laboratory diagnosis of C. difficile-associated diarrhea. To optimize specificity and sensitivity its use should be restricted to patients where the diagnosis is strongly suspected and a rapid answer is required. As it does not distinguish between toxigenic virulent C. difficile strains and non-toxigenic avirulent strains, it would seem prudent to confirm positive results subsequently by demonstrating in-vivo or in-vitro cytotoxin production.

Adolescent↗
PubMed1986

Autoradiographic localization of ornithine decarboxylase in cerebellar cortex of the developing rat with [3H]alpha-difluoromethylornithine.

Ornithine decarboxylase was autoradiographically localized in the developing rat cerebellar cortex after intracisternal injection of [3H]alpha-difluoromethylornithine, a specific, irreversible inhibitor of the enzyme. At nine days of age, when cerebellar ornithine decarboxylase activity is maximal, autoradiographic grains were distributed over all layers of the cerebellar cortex and throughout the brain stem. Within cerebellar folia, the highest grain density was associated with the molecular layer, whereas the internal and external granule cell layers were less densely labeled. Enhancement of ornithine decarboxylase activity by intracisternally-administered isoproterenol correspondingly increased the autoradiographic grain density over each layer. Thus much of the polyamine biosynthetic capability needed to support neuronal and/or glial differentiation appears to be associated with the developing cell processes. The combination of [3H]alpha-difluoromethylornithine autoradiography with localized injection techniques provides a potentially powerful tool for the study of the involvement of polyamine biosynthesis in brain development.

Animals↗
PubMed1986

Charcoal hemoperfusion for the treatment of a combined diltiazem and metoprolol overdose.

We describe the management of a 49-year-old woman who ingested 1,200 mg diltiazem and 500 mg metoprolol. The patient was bradycardic and hypertensive, requiring large doses of inotropic agents and temporary transvenous pacing. Charcoal hemoperfusion was used as an adjunct technique to hasten drug elimination; it rapidly lowered plasma drug levels, with a parallel improvement in the patient's clinical condition.

Charcoal↗