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Biomedical subjects

B Guthrie

Publications and source records attributed to B Guthrie.

30 records · Page 2Linked to original sources

Peripheral benzodiazepine receptors and glucose metabolism in human gliomas.

Peripheral benzodiazepine receptors (PBR) are increased in gliomas and augmented glucose metabolism is seen in malignant brain tumors. We investigated the relationship between PBR density (Bmax) and glucose utilization rate (GUR) in 17 patients with cerebral gliomas of different grades. PBR Bmax was assessed by [3H]PK-11195 in vitro binding in surgical specimens and GUR was measured by Positron Emission Tomography with [18F]2-Fluorodeoxyglucose before the surgery. In untreated tumors there was a positive correlation between PBR Bmax and GUR (2r = 0.84). This correlation was not observed in patients who had been treated with radiation and/or chemotherapy prior to surgery (r2 = 0.13). In addition, in untreated patients, the increase in PBR density and GUR appeared to be related to the degree of malignancy.

Adult↗

Increasing cervical cancer screening among minority elderly. Education and on-site services increase screening.

Older women participate in cervical cancer screening less regularly than do younger women. As a consequence, more lesions are found in more advanced and less curable stages in older women. Elderly black and Hispanic women have had lower rates of participation in cervical cancer screening than white women. There is a marked, inverse relationship between the stage of cervical cancer at diagnosis and the 5-year survival rate. The rate of cervical cancer screening among older women can be increased by offering education about Pap tests and onsite cervical cancer screening in housing for the elderly.

Adult↗

Trigger factor depletion or overproduction causes defective cell division but does not block protein export.

Trigger factor is an abundant cytosolic protein of Escherichia coli which can stabilize proOmpA for in vitro translocation across inner membrane vesicles. The gene encoding E. coli trigger factor was isolated and sequenced, allowing construction of strains in which the expression of trigger factor is readily regulated. We found no defect in the in vivo rate of synthesis or secretion of proOmpA in trigger factor-depleted cells. The primary physiological defect in trigger factor-depleted or -overproducing cells is an enrichment of filamented cells. Filamentation of the trigger factor-overproducing strain is suppressed by a multicopy plasmid expressing the essential division gene ftsZ, suggesting that trigger factor has an important role in cell division.

Amino Acid Isomerases↗

ProOmpA is stabilized for membrane translocation by either purified E. coli trigger factor or canine signal recognition particle.

We have isolated large amounts of E. coli outer-membrane protein A precursor (proOmpA). Purified proOmpA is active in membrane assembly, and this assembly is saturable with respect to the precursor protein. A proOmpA-Sepharose matrix allows affinity isolation of trigger factor, a soluble, 63,000 dalton monomeric protein that stabilizes proOmpA in assembly competent form. Comparison of trigger factor's amino-terminal sequence with those in a computer data bank and with those encoded by sec genes, as well as groEL and heat shock gene dnaK, suggests that trigger factor is encoded by a previously undescribed gene. Trigger factor and proOmpA form a 1:1 complex that can be isolated by gel filtration. Purified canine signal recognition particle (SRP) can also stabilize proOmpA for membrane insertion. This postribosomal activity of SRP suggests a unifying theme in protein translocation mechanisms.

Amino Acid Isomerases↗

The "trigger factor cycle" includes ribosomes, presecretory proteins, and the plasma membrane.

Trigger factor is a soluble, 63,000 dalton protein of E. coli that stabilizes proOmpA, the precursor form of a major outer-membrane protein, in a conformation competent for in vitro membrane assembly. There is approximately one trigger factor molecule bound to each 70S ribosome isolated from cell extracts in physiological buffers. Trigger factor dissociates from ribosomes in 1.5 M LiCl and reassociates with salt-washed ribosomes in low-salt buffer. Binding is exclusively to the 50S (large) subunit, known to contain the exit domain for nascent polypeptide chains. In addition to its associations with proOmpA and ribosomes, excess trigger factor can compete with the proOmpA-trigger factor complex for a limited number of membrane sites that are essential for translocation of proOmpA. These data suggest a model of trigger factor cycling between the cytoplasm, the ribosome, presecretory proteins, and membrane receptor proteins.

Amino Acid Isomerases↗

African-American women who smoke crack cocaine: sexual trauma and the mother-daughter relationship.

This study evolved from previous writings that linked sexual abuse to the quality of the mother-daughter relationship. The purpose of this investigation was to examine the mother-daughter relationship among African-American women who abuse crack cocaine by comparing three different groups: women who have not experienced incest but have experienced sexual abuse; women who have experienced incest; and women who have not experienced sexual abuse. A convenience sample of 64 African-American women was used, 35 of whom were in drug abuse treatment and 29 of whom were abusing crack cocaine. Using analysis of variance studies, significant differences were found between the three groups in terms of the mother-daughter relationship. Differences were also found between the group that experienced incest and the group that experienced nonincestuous sexual abuse in terms of the amount of abuse and first age of abuse. This preliminary investigation indicates the need for further study of specific populations in this area--most notably, African-American women who abuse crack cocaine.

Adult↗

HIV at the hospital/general practice interface: bridging the communication divide.

Good communication between hospital HIV units and general practitioners is essential if people with HIV are to receive appropriate medical care in the community. However, in the UK the experience of general practitioners looking after people with HIV has been that communication is often inadequate. The reasons for this relate to the way that the HIV epidemic has evolved in the UK and the way that health services providing care in HIV have developed. In this review we will examine the causes of the present situation and suggest ways of improving communication which will have beneficial effects on the care of people with HIV.

Communication↗

Changing antibiotic prescribing by educational marketing.

A controlled cross-over study in 12 Victorian public hospitals was performed to examine the power of marketing techniques in influencing prescribing. The targeted prescribing behaviour was the use of antibiotic prophylaxis in surgery, and the criteria for judging the appropriateness of therapy were its duration and timing, as are detailed in the fourth edition of the booklet Antibiotic guidelines. The first intervention was mounted in 1985 in six hospitals (two metropolitan teaching hospitals, one suburban general hospital and three rural hospitals), and six matched hospitals acted as control hospitals. One year later, the intervention was mounted in the six hospitals that previously had been the control hospitals. The interventional campaign consisted of material that was similar to that which is used by the pharmaceutical industry, including an "academic" representative. Its effect was assessed by audits that were performed before and after the first interventional campaign and again, one year later, after the second interventional campaign. The proportion of antibiotic courses that were assessed as satisfactory in terms of duration increased significantly after the first campaign in the hospitals where the intervention was mounted. No significant changes in prescribing occurred in the control hospitals. In the hospitals which were control hospitals in 1985, and in which the intervention occurred in 1986, the proportion of antibiotic courses that were assessed as satisfactory also increased significantly after the interventional campaign. A fall-off in performance occurred during the 12 months after the campaign in the 1985-interventional hospitals. Calculated cost savings more than outweighed the costs of the campaign. We conclude that inappropriate prescribing behaviour in hospitals can be modified successfully by educational marketing techniques.

Anti-Bacterial Agents↗