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Biomedical subjects

R Walker

Publications and source records attributed to R Walker.

At least 19 recordsLinked to original sources
PubMed1992

Changes in drug treatment after discharge from hospital in geriatric patients.

OBJECTIVES: To ascertain changes in drug treatment of elderly patients after discharge from hospital and to identify areas of communication which may require improvement. DESIGN: Follow up of patients six to 14 days after discharge, when the drugs supplied by the hospital should have run out and a further supply obtained from the general practitioner. Patients were also asked about information supplied to them by health care professionals during their hospital stay. SUBJECTS: 50 elderly patients discharged from five geriatric wards (mean age 76.9 years). SETTING: Sunderland District Health Authority. MAIN OUTCOME MEASURE: Drugs taken after discharge from hospital. RESULTS: After returning home the drug regimen of 45 patients differed from that prescribed on discharge from hospital, with 11 patients taking a different dose, 10 having stopped drugs, and 20 taking new drugs. Possible influencing factors included an incomplete drug history, the continuation of drugs taken before hospital admission, and changes in the prescription not attributable to a conscious clinical decision. Lack of information also contributed; 46 patients could not recall being told when to take drugs before discharge. CONCLUSION: Closer communication is needed between hospital and community health care professionals to ensure that patients are informed about their discharge prescription and continuation of treatment.

Aged↗
PubMed1992

Expression of human transforming growth factor alpha by Chinese hamster ovarian tumors in nude mice causes hypercalcemia and increased osteoclastic bone resorption.

Transforming growth factor alpha (TGF-alpha) is a polypeptide regulator of cell growth produced by many malignant tumors. It stimulates osteoclastic resorption in bone organ culture and osteoclast-like cell formation in marrow culture. To determine whether tumor production of TGF-alpha can cause hypercalcemia in vivo, we used Chinese hamster ovarian (CHO) cells transfected with the human TGF-alpha gene (TCHO), which stably express and secrete TGF-alpha. We used nontransfected CHO cells as controls (CCHO). TCHO and CCHO were inoculated intramuscularly into one hindlimb of nude mice and grew as local solid tumors. After 4 weeks of TCHO tumor growth, plasma ionized calcium (Ca2+) increased to reach 1.48 +/- 0.03 mM (mean +/- SEM), whereas mice bearing similarly sized CCHO tumors and non-tumor-bearing mice (NTB) remained normocalcemic (normal range for Ca2+, 1.15-1.30 mM). Plasma TGF-alpha was undetectable by an ELIFA assay in all NTB mice, was markedly increased in all TCHO mice (5.75 +/- 0.78 ng/ml), and was slightly increased in CCHO mice (0.50 +/- 0.22 ng/ml). Quantitative bone histomorphometry showed a prominent increase in osteoclastic bone resorption in TCHO mice. These data suggest that TGF-alpha is a mediator of hypercalcemia and increased osteoclastic bone resorption in tumors that produce it in sufficient quantity.

Animals↗
PubMed1992

Reduction of ischemic heart disease risk markers in the teenage children of heart attack patients.

BACKGROUND: Families of people with ischemic heart disease (IHD) are likely to share high levels of risk markers and to have similar lifestyle patterns. Teenage children in such families were the focus of a behavioral intervention program. METHODS: Families were randomly allocated to either an "early" or a "late" advice group. The late group and a third "control" group (consisting of families with no cardiovascular disease) received the intervention only after baseline measurements were repeated in all three groups at the end of 12 months. Pedigree analysis was used to compare changes across groups. RESULTS: The decrease in self-reported total fat intake was greater among teenagers in the early group (mean = -3.38, SE = 1.00) than among those in the late group (mean = -0.58, SE = 1.06), as was the decrease in saturated fat intake (mean = -2.46, SE = 0.56; mean = -0.54, SE = 0.60, respectively). These differences were statistically significant (P < 0.05). There were no differences between these groups for changes in total or high-density lipoprotein cholesterol levels. There was a statistically significant difference between the change in total cholesterol levels in the control group (mean = +0.08, SE = 0.07) and that in the late group (mean = -0.14, SE = 0.11). CONCLUSIONS: The intervention program appears to have made the teenagers aware of high-fat foods, as stated fat intake was significantly lowered, but it was not successful in decreasing blood cholesterol levels. Having a parent with IHD did, however, influence the teenagers' risk-related behavior, leading to a significant reduction in blood cholesterol levels.

Adolescent↗
PubMed1992

Antimutagenicity of ellagic acid towards the food mutagen IQ: investigation into possible mechanisms of action.

The ability of the plant phenol ellagic acid to inhibit the mutagenicity of the food mutagen IQ was evaluated using Salmonella typhimurium strain TA98 in the Ames mutagenicity test. Ellagic acid caused a concentration-dependent decrease in the S-9- and microsome-mediated mutagenicity of IQ. The plant phenol did not interact directly with the IQ-derived mutagenic species and did not modify the cytosol-mediated activation of the promutagen. At the concentrations used in the mutagenicity studies, ellagic acid failed to inhibit microsomal mixed-function oxidase activity, including that mediated by the P450I family responsible for the bioactivation of IQ, despite being an essentially planar molecule as indicated by computer-graphic analysis. The inhibitory effect of ellagic acid was independent of its ability to chelate Mg2+. However, pre-incubation of ellagic acid with the bacteria, followed by removal of the plant phenol, did not completely prevent the inhibitory effect of the phenol on the mutagenicity of IQ. Intraperitoneal administration of ellagic acid to rats caused a decrease in total cytochrome P-450 levels and related activities as well as in cytosolic glutathione S-transferase activity. Finally, the possibility that the reported anticarcinogenic action of ellagic acid reflects nothing more than non-selective destruction of hepatic cytochromes P-450, and thus reduced chemical activation, is considered.

Animals↗
PubMed1992

Increased tissue concentrations of the gastrin precursor in patients treated with omeprazole.

The main form of gastrin in antral mucosa, the amidated heptadecapeptide G17, is generated from an inactive precursor, progastrin, by steps involving endopeptidase cleavage and amidation. Gastrin cells are normally inhibited by gastric acid and in this study we have examined how suppression of acid by treatment with omeprazole for 6-8 weeks influences gastrin production in patients with oesophagitis. Plasma concentrations of total amidated gastrins in the fasting state increased from 18 to 43 pmol l-1; assays specific for G17-immunoreactivity indicated that the plasma concentrations of this form increased from 6 to 12 pmol l-1. In endoscopic biopsies of antral mucosa there was no change with omeprazole treatment in the concentrations of total amidated gastrins, or their immediate precursors, the Gly-extended gastrins. However, assays using an antibody that reacts with progastrin, together with size exclusion chromatography, indicated that tissue progastrin concentration increased 6-fold. The data suggest a modest net increase in gastrin production with omeprazole-treatment; because the ratio of tissue concentrations of total amidated gastrins to Gly-extended gastrins did not change, it would seem that the amidating capacity of the gastrin cell was maintained. However, the increase in progastrin concentrations suggests a relative failure of the initial steps of post-translational processing, and consequently that in certain circumstances endopeptidase cleavage of progastrin may be rate limiting.

Amino Acid Sequence↗
PubMed1992

v-mos proteins encoded by myeloproliferative sarcoma virus and its ts159 mutant.

The myeloproliferative sarcoma virus (MPSV) v-mos protein was predicted to be identical in size to p39c-mos because of an observed one-base deletion in the seventh codon of the env-mos open reading frame, which would allow translation to initiate at the methionine equivalent to codon 32 of the env-mos gene. On the basis of published results, p39c-mos is known to have greatly reduced in vitro protein kinase activity compared with p37env-mos encoded by Moloney murine sarcoma virus. Unexpectedly, the relative activity of the MPSV v-mos protein kinase was comparable to that of p37env-mos. Consistent with this finding, the size of MPSV v-mos protein was found to be similar to the size of p37env-mos. Moreover, the pattern and sizes of phosphorylated bands produced by autophosphorylation of the MPSV v-mos protein were similar to those of p37env-mos. These results were confirmed by in vitro transcription-translation of the MPSV v-mos gene. Resequencing portions of the MPSV mos gene failed to show the deletion within codon 7. Except for the codon 262 deletion, other mutations characteristic of MPSV and temperature-sensitive MPSV v-mos genes were confirmed. A glycine-to-arginine mutation at residue 338 of the MPSV env-mos sequence, previously shown to cause thermosensitivity of the mutant virus (termed ts159) transforming function, yielded a v-mos protein that had significantly reduced protein kinase activity in vitro. These findings indicate that MPSV, like other Moloney murine sarcoma virus strains, also encodes a functional env-mos protein.

Amino Acid Sequence↗
PubMed1992

[Periodic health examination].

A literature search has been made on the examinations to be performed during the "periodic health exam" on the healthy adult. These examinations shall be performed bearing in mind the prevalence and morbility data of the specific diseases, individual risk factors and the quality (sensibility and specificity) of the diagnostic procedure. The value of regular blood pressure determination, breast exam and cervical cytology with Papanicolaou stain, is well established. However, there is no consensus regarding other determinations, due to the fact that different authors use different approaches. The skin, mouth and thyroid examination for cancer screening is limited only to individuals having risk factors. Heart auscultation for the diagnosis of valvulopathies that could required antibiotic prophylaxis for bacterial endocarditis is important. In individuals over sixty years old, vision acuity and hearing capabilities should be explored, also abdomen should be explored to detect aortic aneurysms. Hypercholesterolemia should be determined in individuals over 20 years old, and PPD should be performed before 35 years old. Concerning the rest of explorations (rectal taction, testicular exploration, etc.) its efficacy has not been clearly established in the screening.

Physical Examination↗
PubMed1991

PRN psychotropic drug use on a psychiatric unit.

PRN psychotropic drug use is a frequent practice on psychiatric units. This study examined medical records for patient demographics and prescribing patterns of drugs. The omission of the indication and frequency of dosing for the drug were common prescribing errors. There was no significant association between diagnosis and whether a patient received PRN drugs. Anxious patients were significantly more likely to receive PRN anxiolytics whereas psychotic patients were as likely to receive PRN anxiolytics as antipsychotics. Anxiolytics also were significantly more likely to be judged effective by the nursing staff than antipsychotics. A perplexing finding was that manic and schizophrenic patients were significantly less likely to receive PRN hypnotics than were patients with Major Depression. The clinical implications of the findings are discussed and recommendations are made to improve standards of practice for this commonplace treatment.

Adult↗
PubMed1991

Disentangling neglect and hemianopia.

In this paper we report findings which question the diagnosis of a hemianopia in B.Q., a 66-year-old lady who shows unilateral spatial neglect following a lesion to the right parietal lobe. The presence of a hemianopia has been indicated following two independent assessments of B.Q.'s visual fields. We examined B.Q.'s performance on a visuo-spatial task in which single or double stimuli were displayed left and right of a central fixation point. B.Q. failed to report left stimuli when the fixation point was continuously displayed (OVERLAP CONDITION). This performance is consistent with the suggestion of a left hemianopia as indicated by perimetric field testing. In a further condition the fixation point was extinguished prior to stimuli onset (GAP CONDITION). B.Q. consistently responded to left stimuli in the gap condition and also showed improved performance to right stimuli. Eye movements were recorded on a separate testing session, in which B.Q. showed a normal saccadic response to left targets in the gap condition, but not during the overlap condition. These results suggest that B.Q.'s failure to report left stimuli during field plotting is due to her neglecting left stimuli and not because she has a visual field defect. By using a testing procedure which reduces the severity of neglect B.Q. is able to respond to left stimuli. Reducing the severity of B.Q.'s neglect also abolishes the apparent hemianopia. Standard field plotting techniques which use a consistently displayed fixation point may not be appropriate for the testing of neglect patients' visual fields.

Aged↗
PubMed1991

Influence of dietary protein and gut microflora on endogenous synthesis of nitrate induced by bacterial endotoxin in the rat.

Germ-free (GF) rats were maintained on a diet marginally adequate in protein, with and without a supplement of NH4Cl. Their urinary excretion of total nitrogen, nitrate, urea and creatinine was measured before and for 4 days after injection of Escherichia coli endotoxin (lipopolysaccharide; LPS). Although more nitrogen was excreted by rats on the diet supplemented with NH4Cl, nitrate excretion was increased to a similar extent in rats on both diets. This suggests that oxidation of ammonia released by deamination of amino acids is an unlikely pathway of nitrate synthesis. In a second experiment, nitrate excretion before and after injection of LPS was measured in GF and conventional (CV) rats given high- or low-protein diets. Urinary 3-methylhistidine (3MH) was measured as an index of breakdown of tissue protein. In both environments, nitrate excretion was significantly greater, before and after LPS administration, by rats on the high-protein diet than by their counterparts on the low-protein diet, and was generally greater by GF than by CV rats. Since only small, non-significant rises in urinary 3MH were observed after LPS treatment, it was concluded that the bulk of the nitrogen required for nitrate synthesis in response to endotoxin is derived from dietary protein rather than from nitrogenous products of tissue breakdown.

Administration, Oral↗
PubMed1991

Applications of chemical-shift-selective NMR microscopy to the non-invasive histochemistry of plant materials.

Chemical-shift-selective imaging at microscopic resolution has been applied to the study of various plant materials including orange peel, grape berries and both dried and undried fruits of fennel. It is shown that selective imaging of aromatics and carbohydrates as well as water and oil can be performed with in-plane resolution down to 13 microns and slice thicknesses of 1 mm or less, at a field strength of 4.7 Tesla. The noninvasive nature of the method gives it advantages over established methods of plant histochemistry which involve sectioning and staining to reveal different chemical constituents.

Fruit↗