Search PubMed⌕ Search

Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 451 records · Page 25Linked to original sources
PubMed1988

Human immunodeficiency virus infection in patients with leukemia.

Eighteen human immunodeficiency virus (HIV)-seropositive patients were found among 211 previously treated adult patients with a variety of leukemias who had been multiply transfused before April 1985. Patients known to be homosexual or intravenous drug users were excluded from this study. The spouse of one HIV-seropositive patient became HIV infected and subsequently developed the acquired immune deficiency syndrome. Patients with leukemia who were multiply transfused before the availability of screening of blood products for HIV antibody should be counseled regarding their individual risks of HIV infection and the risk to sexual contacts.

Female↗
PubMed1988

Screening mutant mice for inborn errors of metabolism.

We described our methods of screening mice for inborn errors of metabolism including metabolic storage diseases, disorders of amino acid metabolism, and organic acidemias. Our screening program consisted of histopathology, quantitative serum amino acid analysis, and urinary organic acid analysis. In this preliminary study, we tested mice representing 28 different mutations whose clinical signs suggested a possible metabolic disorder. We documented the normal values for mouse serum amino acids and urinary organic acids. No mutant tested had relevant or consistent biochemical abnormalities as determined by our screening tests. Some mutants showed histopathology as described previously. However, we were unable to confirm the histopathology described originally for the shambling mutant.

Amino Acids↗
PubMed1987

Alternative methods of selecting rat hepatocellular nodules resistant to 2-acetylaminofluorene.

Dietary 2-acetylaminofluorene (2-AAF) coupled with a stimulus for cell proliferation such as a 2/3 partial hepatectomy (PH) or a necrotizing dose of carbon tetrachloride is frequently employed to generate nodules of resistant ("initiated") rat hepatocytes. This regimen is a useful model for experimental analysis of alterations in hepatocytes during carcinogenesis, and also as an assay for initiation by various carcinogens. Because of the decreasing availability of carcinogen-containing diets from commercial sources, we have developed alternative methods of 2-AAF administration to generate nodules in rats initiated with N-nitrosodiethylamine. This study compared the nodule-selecting and cancer-promoting efficacy of 2-AAF administered by the Solt-Farber procedure (0.02% in diet for 2 weeks) with 2-AAF administered by gavage, as a suspension in 1% aqueous carboxymethyl-cellulose (CMC). Three or 4 daily administrations of 2-AAF by gavage (20 mg/kg/day) followed by PH on day 4 were equivalent to the dietary regimen in generating early resistant nodules, late persistent nodules and hepatocellular carcinomas. These regimens were similar to the dietary regimen of 2-AAF in inhibiting virtually all normal hepatocyte proliferation. These regimens permit control over the duration and level of 2-AAF exposure and the resulting size of selected nodules.

2-Acetylaminofluorene↗
PubMed1987

Bacteremia and fungemia in patients with neoplastic disease.

This study reviewed 431 episodes of septicemia occurring in 356 patients with cancer at Memorial Sloan-Kettering Cancer Center during 1982. The most frequent organisms causing 273 episodes in 239 non-neutropenic patients were Escherichia coli (20 percent), Staphylococcus aureus (13 percent), polymicrobic (12 percent), Pseudomonas species (8 percent), Klebsiella species (7 percent), Candida species (7 percent), Bacteroides species (6 percent), Enterobacter species (4 percent), and Clostridium species (4 percent). The overall mortality was 31 percent (21 percent with adequate therapy; 50 percent with inadequate therapy). The most frequent organisms causing 158 episodes in 117 neutropenic patients were polymicrobic (21 percent), E. coli (16 percent), Klebsiella species (15 percent), Pseudomonas species (8 percent), Candida species (6 percent), S. aureus (6 percent), Streptococcus faecalis (5 percent), S. epidermidis (4 percent), and Corynebacterium CDC-JK (3 percent). The overall mortality was 52 percent (36 percent with adequate therapy; 88 percent with inadequate therapy). Since a review a decade ago, the spectrum of organisms changed in that the gram-positive organisms, S. faecalis, S. epidermidis, and C. CDC-JK, emerged as important pathogens. Neutropenic patients had a high incidence (42 percent) of septicemia due to multiple organisms, occurring concurrently or sequentially. The overall mortality of these patients was exceptionally high (80 percent). In contrast, the overall mortality of neutropenic patients with single-organism septicemia was comparable to that of non-neutropenic patients with single-organism septicemia (37 percent versus 29 percent).

Adolescent↗
PubMed1987

Silence and truth in death and dying.

Since about 1960 a socio-medical literature has emerged which asserts the importance of truth in the dialogue between dying patient and medical attendant; at the same time the former regime of silence is condemned. This paper argues against the implication that truth and silence are in opposition, and moreover that it is only since 1960 that it has been possible to speak the truth about death. Rather what has changed is the nature of truth itself which is manifested in the shift from the interrogation of the corpse to that of the dying patient.

Attitude to Death↗
PubMed1987

Theoretical tensions in biopsychosocial medicine.

Orthodoxy traditionally manages to control the potential threat from the unorthodox by a strategy of either marginalisation or incorporation. Having for so long marginalised the social sciences, biomedicine now seeks to incorporate them in a new biopsychosocial alliance. The social sciences should resist such blandishments and, rather than act in complicity with biomedicine, be free to pursue a more critical role in exposing the theoretical and empirical inconsistencies in the biomedical model.

Biological Psychiatry↗
PubMed1987

Severe cardiopathy in branching enzyme deficiency.

A 7 1/2-year-old girl had exercise intolerance and exertional dyspnea. Four months later, congestive heart failure developed, with recurrent chylous pleural effusions, and she died at age 8 1/2 years. Endomyocardial biopsy tissue showed abundant PAS-positive, diastase-resistant cytoplasmic deposits. Similar inclusions were seen in muscle, skin, and liver specimens. Postmortem studies showed that the abnormal polysaccharide was especially abundant in heart and muscle, but was also present in all other tissues, including the central nervous system. Glycogen isolated from heart, muscle, and spinal cord showed a shift of the iodine spectrum toward higher than normal wavelengths. Branching enzyme activity was lacking in the muscle biopsy specimen and in all postmortem tissues; glycogenolytic enzymes had normal activities. These studies show that cardiomyopathy can be the first symptom of generalized branching enzyme deficiency and that the degree of accumulation of the abnormal polysaccharide may vary in different tissues.

Biopsy↗
PubMed1987

Voltage-activated calcium channels that must be phosphorylated to respond to membrane depolarization.

Two classes of calcium channels were activated by membrane depolarization in cell-free membrane patches from GH3 cells, an electrically excitable cell line derived from a mammalian pituitary tumor. One class had a conductance of approximately 10 pS in 90 mM barium, had a threshold of activation near -40 mV, and was inactivated rapidly at holding potentials more positive than -80 mV. The other class, with a conductance of approximately 23 pS and a threshold nearer -20 mV, did not inactivate in barium but stopped responding to depolarization altogether when the cytoplasmic side of the patch was exposed to a standard physiological saline solution. Buffering the concentration of calcium ions to less than 10 nM on the cytoplasmic side did not prevent this loss of activity. However, activity was restored and maintained for the duration of the patch when the catalytic subunit of cAMP-dependent protein kinase was added with MgATP to the cytoplasmic side of the membrane. Cell-free patch formation in the presence of the dihydropyridine, BAY K 8644, also delayed the loss of activity, but unlike the catalytic subunit plus ATP, BAY K 8644 alone did not restore activity when it was added after the channels no longer responded to depolarization. Evidently the dihydropyridine-sensitive class of voltage-activated calcium channels must be phosphorylated in order to open when the membrane is depolarized. That hypothesis provides a simple framework for understanding the modulation of calcium channel gating by neurotransmitters, calcium ions, and dihydropyridines.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1987

Reduction of substituted flavins by .CO2- and cyclic disulphide anions.

5-Deazariboflavin was observed to undergo one electron-equivalent reduction on reaction with .CO2-, DS2-. or a mixture of .CO2- and eaq-. This is attributed to formation of .FlH, followed by dimerization: 2 5-DRFlH.----(5-DRFlH)2 a process not previously confirmed. In contrast, 3-deazariboflavin, 1-deazariboflavin 7-chlororiboflavin, 2-thioriboflavin, lumiflavin, flavin adenine dinucleotide and riboflavin all underwent two electron-equivalent reductions to FlH2 or FlH-species via the disproportionation: 2.FlH----FlH2+Fl Spectra of the reduced species are reported for 3-deazariboflavin, 1-deazarboflavin and 2-thioriboflavin. The anion radicals of dithiothreitol (DS2-.) and lipoamide (LS2-.) did not effect reduction beyond the two electron equivalence point. However, .CO2- was seen to effect further reactions with the dihydroforms of the higher redox potential flavins 7-chlororiboflavin and 2-thioriboflavin at pH 3 to 10, but for the other flavins only at or below pH 2. Except for the sulphur-containing 2-thioriboflavin, the protonated DS2.H and LS2.H radicals were unable to reduce any of the flavins at pH less than or equal to 3. This cause a 'falloff' in the yield of the reduced flavin which is in accord with the reaction rate constants and radical pK values. Despite their differences in absorbance, the reactions of DS2.H and LS2.H towards flavins were similar in all aspects examined. Several new rate constants are reported.

Anions↗
PubMed1987

Referral to hospital: perceptions of patients, general practitioners and consultants about necessity and suitability of referral.

A sample of new referrals from general practitioners to hospital specialists was examined from the points of view of the patient, general practitioner and consultant concerned with regard to the adequacy of the general practitioners' performance before referral, his ability to have managed without referral and the suitability of the specialist seen. Little agreement was found between the opinions expressed by the three groups, although some of the opinions expressed within the groups were found to be associated with characteristics of the groups.

Consultants↗
PubMed1987

Liver infection caused by Coniothyrium fuckelii in a patient with acute myelogenous leukemia.

A case of liver infection caused by Coniothyrium fuckelii is described in a patient with acute myelogenous leukemia. This fungus is found in the soil and can be a pathogen of plants. Coniothyrium spp. are members of the order Sphaeropsidales, an order composed of fungi whose conidiomata are usually pycnidia with the conidiogenous hymenium lining the walls of the locule. Coniothyrium spp. must be differentiated from Phoma spp. and Hendersonula spp., the two most commonly isolated members of the Sphaeropsidales.

Female↗