Biomedical subjects
A Graham
Publications and source records attributed to A Graham.
Welfare benefits. Defying the directive.
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Biosensors: recent trends.
One of the major bottlenecks in automation and process control of industrial bioprocesses is the lack of suitable sensing devices to accurately measure the concentrations of biomolecules. The measurement of ions (e.g., H(+), NH(4)(+)) and gases (e.g., O(2), CO(2), NH(3)) using standard ion-selective and gas sensing electrodes respectively, is well established. Chemical analysis of biomolecules off-line is generally unreliable, labour intensive and may lead to contamination of the biological systems. Problems of maintaining sterile conditions are especially important when dealing with slow growing mammalian or plant cells in culture. Active research in the development of biosensors for monitoring fermentation processes, food production and pollution control, and for medical and veterinary applications is currently underway. This paper reviews recent approaches toward the development of biosensors which involve a biochemical interaction to measure the concentrations of biomolecules, primarily for the on-line monitoring and control of fermentation processes.
Neuralgic amyotrophy with bilateral diaphragmatic palsy.
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Welfare benefits: when an increase masks cuts; reading the small print.
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Hypoxia, depression of testosterone, and impotence in pickwickian syndrome reversed by weight reduction.
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Welfare benefits: severely degrading allowance.
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Elevated alpha-fetoprotein and acetylcholinesterase associated with hydrocele.
Elevated amniotic fluid alpha-fetoprotein and presence of acetylcholinesterase were detected in a pregnancy that resulted in an infant whose only abnormality was a hydrocele. Although these amniotic fluid findings are usually indicative of a serious fetal anomaly, our report indicates that this is not always the case.
The role of suppression of DNA synthesis and inhibition of cell cycle progression in cellular sensitivity to alkylation damage.
A u.v. sensitive Chinese hamster cell line V79/79 has been shown to be also more sensitive to methyl methanesulphonate (MMS) and nitrogen mustard (HN2) exposure than wild-type V79 cells. A comparison of the effects of the two alkylating agents on DNA synthesis measured by [3H]thymidine (TdR) incorporation into whole cells and by alkaline sucrose gradient sedimentation 14C-labelled template and of pulse labelled DNA revealed no significant differences between the responses of the two cell lines. The effects of a range of doses of both drugs on the rate of progress through the cell cycle was compared using cytofluorimetry. The more sensitive V79/79 cells failed to show a significant delay in progress through the cell cycle even at the highest doses tested (0.2 microM HN2 and 2.0 mM MMS). In contrast, V79 cells showed a marked S phase delay in response to both HN2 and MMS exposure. The possible relationships between failure to delay cell cycle progression, and cellular sensitivity are discussed.
Escherichia coli formate to nitrate respiratory pathway: structural analysis.
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How family practice patients view their utilization of mental health services.
This study examines to what extent family practice patients perceive themselves as being willing to seek help for personal problems. The study further explores whether this willingness is related to various demographic characteristics. Finally, it investigates family practice patients' preferences in their choice of a source of help for personal problems. Patients in the waiting room of a private family practice center were approached to participate in the study at random times during one month (n = 145). For each item of a list of common personal problems, patients were asked to judge how likely they would be to seek professional help, their preferred setting for this help, and their preference of a professional provider. Respondents' sex was found to be the only demographic characteristic that affected willingness to seek help. "The family physician's office" and "the family physician" were the preferred choices mainly for personal problems associated with physical manifestations. Other providers were chosen for predominantly social or emotional problems. Most respondents stated that they would be more likely to seek help from a mental health professional who worked along with the family physician than they would be to seek help from a professional housed elsewhere.
The organization of hydrogenase in the cytoplasmic membrane of Escherichia coli.
The organization of the membrane-bound hydrogenase from Escherichia coli was studied by using two membrane-impermeant probes, diazotized [125I]di-iodosulphanilic acid and lactoperoxidase-catalysed radioiodination. The labelling pattern of the enzyme obtained from labelled spheroplasts was compared with that from predominantly inside-out membrane vesicles, after recovery of hydrogenase by immunoprecipitation. The labelling pattern of F1-ATPase was used as a control for labelling at the cytoplasmic surface throughout these experiments. Hydrogenase (mol.wt. approx. 63 000) is transmembranous. Crossed immunoelectrophoresis with anti-(membrane vesicle) immunoglobulins, coupled with successive immunoadsorption of the antiserum with spheroplasts, confirmed the location of hydrogenase at the periplasmic surface. Immunoadsorption with sonicated spheroplasts suggests that the enzyme is also exposed at the cytoplasmic surface. Inside-out vesicles were prepared by agglutination of sonicated spheroplasts, and the results of immunoadsorption using these vesicles confirms the location of hydrogenase at the cytoplasmic surface.
The organization of formate dehydrogenase in the cytoplasmic membrane of Escherichia coli.
The arrangement of the proton-translocating formate dehydrogenase of the anaerobic respiratory chain of Escherichia coli within the cytoplasmic membrane was examined by direct covalent modification with non-membrane-permeant reagents. Three methods were employed, lactoperoxidase-catalysed radioiodination, labelling with diazotized [125I] di-iodosulphanilic acid and labelling with diazobenzene [35S] sulphonate. All three procedures yield consistent with the view that the two larger subunits of the enzyme, Mr 110000 and 32000, both occupy transmembranous locations within the membrane. In each case the modification of the Ca2+ or Mg2+-activated F1-ATPase was monitored, and all reagents employed correctly located this enzyme at the cytoplasmic face of the membrane. A procedure involving agglutination with specific antibodies is described which appears to fractionate membrane vesicles of mixed orientation into two populations, one with the same membrane orientation as that of spheroplasts and the other opposite orientation.
Enhanced urinary excretion of N1-acetylspermidine and the presence of tumors.
We have studied the urinary excretion of free and acetylated polyamines in hepatoma-bearing Buffalo rats during the period of linear growth of the tumor mass. The excretion of nonconjugated polyamines was unchanged. N1-Acetylspermidine excretion did not parallel the linear increase in tumor mass but increased exponentially. Enhancement of N8-acetylspermidine excretion above control levels was observed only at a time when the average tumor mass was 35 +/- 9 (S.D.) g. shortly before the period when necrosis is usually observed. These data taken together with the analysis of urinary acetylpolyamines in rats bearing mammary tumors and in two melanoma patients show that the determination of the N1-acetylspermidine/N8-acetylspermidine ratio in urine may be of only limited value as an indicator for the presence of tumors.
Educating Tom to take his medicine: a patient teaching programme.
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Pseudolymphoma of the breast.
A case of pseudolymphoma of the breast presenting as an isolated tumor mass in the breast of a 56-year-old female is described. Recognition of this rare lesion is important in order to differentiate it from other malignant neoplasms.
Immunochemical analysis of the membrane-bound hydrogenase of Escherichia coli.
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