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Biomedical subjects

K Gray

Publications and source records attributed to K Gray.

At least 19 recordsLinked to original sources
PubMed2003

Effect of different 5-HT1A receptor antagonists in combination with paroxetine on expression of the immediate-early gene Arc in rat brain.

Selective 5-HT(1A) receptor antagonists enhance the effect of selective serotonin reuptake inhibitors (SSRIs) on presynaptic 5-HT function, and have potential as antidepressant augmentation therapies. The present study tested the effect of different selective 5-HT(1A) receptor antagonists (WAY 100635, NAD-299, p-MPPI and LY 426965) in combination with a SSRI (paroxetine), on postsynaptic 5-HT function measured by increased expression of the immediate early gene, Arc. Paroxetine (5 mg/kg s.c.) combined with WAY 100635 (0.3 mg/kg s.c.) increased Arc mRNA in frontal, parietal and piriform cortices, and caudate putamen. Paroxetine (5 mg/kg s.c.) plus NAD-299 (1 or 5 mg/kg s.c.) had a similar effect. None of these drugs increased Arc mRNA when administered alone. Paroxetine (5 mg/kg s.c.) plus p-MPPI (8.5 mg/kg s.c.) also increased Arc mRNA but p-MPPI itself elevated Arc mRNA in many regions. Whilst LY 426965 (3 or 10 mg/kg s.c.) had no effect alone, when combined with paroxetine (5 mg/kg s.c.), the drug increased Arc mRNA in caudate putamen but not cortical regions.In conclusion, this study demonstrates that four 5-HT(1A) receptor antagonists augment the effect of an SSRI on Arc mRNA expression, which is suggestive of increased postsynaptic 5-HT function. However, the data reveal certain differences in the 5-HT(1A) receptor antagonists not recognised in models of presynaptic 5-HT function.

Aminopyridines↗
PubMed2002

Quality indicators for antibiotic control programmes.

Antimicrobial control measures are commonly perceived to lead to an improvement in quality of prescribing, cost-effectiveness and reduction in resistance. All three outcomes have been subject to scrutiny. As proper use of resources needs to be balanced with provision of high-quality health care, the effectiveness of control measures (antibiotic policies or formularies) must be monitored. Measurement of quality by using specific indicators has been suggested as an effective measure of performance. We describe a model for evaluating core aspects of antimicrobial control programmes, aimed at improving the quality of glycopeptide prescribing by 'appropriate use guidelines'. Prioritizing indicator settings within antimicrobial control programmes is essential if limited resources are to be used most effectively. Indicator development, evaluation and feedback ought to be multi-disciplinary to ensure ownership and long-term benefit.

Anti-Bacterial Agents↗
PubMed2002

Pathways to HIV testing and care by black African and white patients in London.

OBJECTIVE: To examine factors associated with uptake of HIV clinic services by black African HIV positive people living in London. DESIGN: Questionnaire survey of patients attending study clinic. SETTING: HIV outpatient clinic in south London, UK. SUBJECTS: All HIV positive patients attending the clinic between July 1999 and March 2000. MAIN OUTCOME MEASURES: Use of health services, delay in seeking HIV test, pre-HIV test concerns, delay in uptake of HIV care, barriers to clinic use, disclosure, sources of support. RESULTS: 392 questionnaires were completed. Respondents were 64% white, 26% black African, and 10% from other ethnic groups. Twenty eight per cent of black Africans suspected they were HIV positive before diagnosis (white patients 45% (p<0.01)). Before testing 11% of black Africans had previously attended a genitourinary medicine clinic, 80% had consulted a GP. Twenty per cent of black Africans expressed concern over entitlement to care and where to get an HIV test. The majority of black Africans (66%) received HIV care within 1 month of their diagnosis. They were significantly (p<0.01) less likely than white patients to disclose their HIV status to family and friends. CONCLUSION: This study suggests that although black Africans are a high risk group for HIV infection they generally do not suspect their status. While they may delay testing, their uptake of HIV clinic care and use of statutory and voluntary support services after diagnosis is similar to their white counterparts. However, they lack informal support networks. This study highlights the continuing need for health promotion work among London's African communities, to reduce the stigma surrounding HIV/AIDS and to raise awareness of the benefits of testing.

Adult↗
PubMed2001

The farnesyl transferase inhibitor SCH 66336 induces a G(2) --> M or G(1) pause in sensitive human tumor cell lines.

SCH 66336 is a potent farnesyl transferase inhibitor (FTI) in clinical development. It efficiently prevents the membrane association of H-ras, but not K- or N-ras. Yet, in soft agar, it reverts the anchorage-independent growth of human tumor cell lines (hTCLs) harboring H-ras, K-ras, and N-ras mutations, implying that blocking farnesylation of proteins besides ras may be responsible for this effect. Experiments show that SCH 66336 altered the cell cycle distribution of sensitive human tumor cells in two distinct ways. Most sensitive hTCLs accumulated in the G(2)-->M phase after the FTI treatment, but those with an activated H-ras accumulated in G(1) phase, suggesting that the biological effects induced by FTIs in cells with an activated H-ras are distinct from other sensitive cells. A careful genotypic comparison of the hTCLs revealed that those cells with wild-type p53 are especially sensitive to the FTIs. In these cells p53 and its downstream target gene p21(Cip1) are induced after treatment with SCH 66336 for 24 h. These data suggest that cell cycle effects, either G(1) or G(2)-->M accumulation, and p53 status are important for mediating the effects of FTIs on tumor cells.

3T3 Cells↗
PubMed2001

Provision of drugs for post-exposure prophylaxis of HIV for medical students on overseas electives.

OBJECTIVES: To assess the need for, and the most practical way to provide, HIV post-exposure prophylaxis (PEP) for medical students travelling to areas where this is not readily available. METHODS: Follow-up questionnaire for all 140 students from Dundee University returning from their medical elective in 2000, 22 of whom took triple therapy for PEP with them on elective. RESULTS: 103/140 students (74%) returned questionnaires. 76/103 (74%) were involved in exposure-prone procedures and 38/103 (37%) reported a significant exposure to potentially infective fluids. Six of this group considered PEP but none reported using it. The greatest perceived risk on elective remained road accidents. 87/103 respondents thought a 24-h helpline for health issues on electives would be useful. CONCLUSIONS: A high number of students report significant exposure to potentially infected fluids and this needs to be urgently addressed. There was almost unanimous endorsement of the idea of providing PEP and when it is made easily available prior to travel, students are willing to take it to areas where it is not available. In response to the survey, the investigators are looking at how to increase the current limited supply of PEP (Students may have to pay part of the cost) and the best way to provide a helpline, as it is felt that this could have a broad impact on student safety on electives, not just for issues involving PEP.

Accidents↗
PubMed2001

Participation of racial/ethnic groups in clinical trials and race-related labeling: a review of new molecular entities approved 1995-1999.

Few recent data are available from formal evaluations of approved new drug applications to address perceptions that racial and ethnic groups are under-represented in clinical trials of new drugs. This study reviews racial and ethnic group participation in clinical trials and race-related labeling for new molecular entities approved during a five-year period by the Food and Drug Administration's (FDA) Center for Drug Evaluation and Research (CDER). This was a retrospective review of FDA medical officers' reviews of clinical trial protocols and product labeling for 185 new molecular entities (NME's) approved by CDER between January 1,1995, and December 31, 1999. Enrollment data were obtained from the reviews and tabulated according to race/ethnicity. The approved product labeling was searched for statements related to product testing in various racial/ethnic groups. All data were compiled and analyzed using Microsoft Access. This study quantifies the participation of racial/ethnic groups in clinical trials by year and therapeutic category. Additionally, the study categorizes labeling based on the types of effects described as related to race/ethnicity. Racial and ethnic groups appear to participate in clinical trials to varying degrees. African Americans participated in trials to the greatest extent; however, their participation steadily declined from 12% in 1995 to 6% in 1999. Among trials known to be conducted only in the U.S., African-American participation is comparable to their representation in the U.S. population. In all cases, participants designated as Hispanic appear to be far below their representation in the population. Some differences in participation for all racial and ethnic groups are seen when comparisons from year-to-year or among drug classes are made. Labeling for 45% (84/185) of the products contained some statement about race, although in only 8% (15/185) were differences related to race described. Fifty percent (50%) of the effects were pharmacokinetic, 39% were efficacy, and 11% were safety. One product label recommended a change in dosage based on racial differences.

Clinical Trials as Topic↗
PubMed2000

Farnesyl transferase inhibitors block the farnesylation of CENP-E and CENP-F and alter the association of CENP-E with the microtubules.

Human tumor cell lines that are sensitive to the effects of farnesyl transferase inhibitors accumulate in G(2) --> M (except for cells with an activated Ha-ras that accumulate in G(1)). A search for CAAX box proteins from Swiss-Prot revealed more than 300 peptides. Of these, the centromeric proteins CENP-E and CENP-F are preferentially expressed during mitosis and are implicated as mediators of the G(2) --> M checkpoint. Experiments performed here show that peptides from the COOH-terminal CAAX box of CENP-E and CENP-F are substrates for farnesyl transferase but not geranylgeranyl transferase-I. Although both proteins are prenylated in the human tumor cell line DLD-1, their prenylation is completely inhibited by the farnesyl transferase inhibitor, SCH 66336. Immunohistochemical data with the lung carcinoma cell line, A549, showed that preventing the farnesylation of CENP-E and CENP-F by treatment with the farnesyl transferase inhibitor SCH 66336 does not affect their localization to the kinetochores. However, the presence of farnesyl transferase inhibitors alters the association between CENP-E and the microtubules. Our results imply that the inhibition of CENP-E farnesylation results in the alteration of the microtubule-centromere interaction during mitosis and results in the accumulation of cells prior to metaphase.

Alkyl and Aryl Transferases↗
PubMed2000

Endocervical cancer is associated with an increase in the ligands and receptors for transforming growth factor-beta and a contrasting decrease in p27(Kip1).

OBJECTIVE: The aim of this study was to investigate the relationship between the expression of the TGF-beta ligands and TGF-beta receptors to the expression of p27(Kip1), a TGF-beta-regulated gene, in endocervical cancer. METHODS: To examine the expression of TGF-beta and p27(Kip1) in malignant transformation of the uterine endocervix, a panel of 23 formalin-fixed and paraffin-embedded human cervical specimens, including 8 with benign endocervical glands, 8 with cervical adenocarcinoma in situ, and 7 with cervical adenocarcinomas, was used. Tissues were immunostained with polyclonal antibodies that react specifically with TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-beta RI, TGF-beta RII, and p27(Kip1). RESULTS: Immunostaining for TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-beta RI, TGF-beta RII, and p27(Kip1) was detected in normal endocervix, with the TGF-betas showing weak cytoplasmic staining, while p27(Kip1) showed strong nuclear staining. Expression of TGF-beta increased significantly upon neoplastic transformation with the TGF-beta ligands and receptors showing strong cytoplasmic staining in adenocarcinoma in situ compared to normal endocervix. Interestingly, expression of TGF-beta was lower in adenocarcinoma than in adenocarcinoma in situ, but still significantly higher than in normal endocervix. TGF-beta 2 and TGF-beta 3 showed higher levels of immunostaining than TGF-beta 1 in adenocarcinomas. In contrast, p27(Kip1) protein expression decreased with progressive malignancy, with lower p27(Kip1) protein levels detected in adenocarcinoma than in adenocarcinoma in situ, while normal endocervix showed the highest level of p27(Kip1) protein expression. CONCLUSION: Elevated expression of the TGF-beta ligands and receptors is found in both cervical adenocarcinoma in situ and adenocarcinoma compared to normal endocervix. In contrast, a progressive decrease in p27(Kip1) occurs upon neoplastic transformation of the normal endocervix to cervical adenocarcinoma. These results suggest that neoplastic transformation of the endocervix may be related to dysregulation of TGF-beta and p27(Kip1) seen as an elevation of TGF-beta and a reduction of p27(Kip1) expression that may lead to loss of cell cycle control.

Activin Receptors, Type I↗
PubMed2000

Expression of brx proto-oncogene in normal ovary and in epithelial ovarian neoplasms.

OBJECTIVE: We previously identified a protein, Brx, that interacted with estrogen receptor alpha. Sequence analysis determined that Brx is a novel member of the Dbl family of oncoproteins involved in signaling pathways that regulate cell growth. Because the Brx protein was found to be highly expressed in hormoneresponsive breast epithelium, the objective of this study was to determine whether Brx was expressed in both normal and neoplastic ovarian tissues. STUDY DESIGN: A polyclonal antiserum directed against the Brx protein was used to perform immunolocalization on sections from 5 normal ovaries and 20 ovarian neoplasms. Chromosomal localization of the brx gene was accomplished by means of fluorescence in situ hybridization. Northern and Western blot analyses were performed on extracts prepared from human ovaries. RESULTS: Brx protein was localized to the cytoplasm of granulosa cells from mature graafian follicles, the corpus luteum, and islands of hilar cells in normal ovaries. In tumors with low malignant potential and ovarian carcinomas the neoplastic epithelium stained strongly for Brx protein. Northern and Western blot analyses, respectively, confirmed expression of Brx messenger ribonucleic acid and protein in normal ovary. Finally, the brx gene was localized to 15q25. CONCLUSION: The proto-oncogene brx is expressed in specific normal human ovarian tissues and is also present in ovarian epithelial neoplasms.

A Kinase Anchor Proteins↗
PubMed2000

Modulation of endometrial steroid receptors and growth regulatory genes by tamoxifen.

OBJECTIVE: We investigated tamoxifen's effects on the expression of growth regulatory genes in the endometrium to identify the mechanism by which tamoxifen induces proliferation. METHODS: Using immunohistochemical techniques, we analyzed 39 endometrial specimens for expression of Ki-67, lactoferrin, transforming growth factor-alpha, tumor necrosis factor receptor-II, adrenomedullin, estrogen receptors, and progesterone receptors. Twenty specimens were obtained from postmenopausal breast cancer patients treated with tamoxifen (20 mg/day) for at least 6 months to include two endometrial adenocarcinoma specimens. Five secretory phase, three proliferative phase, and seven atrophic endometrial specimens were used as controls. In addition, four endometrial adenocarcinoma specimens were reviewed from patients not treated with tamoxifen. Intensity of immunostaining was quantified using digitized imaging techniques. RESULTS: Overexpression of both estrogen receptors and progesterone receptors, and an elevated proliferative index were the most consistent effects observed in benign endometrial specimens from tamoxifen-treated patients compared with atrophic controls (P <. 003). This staining pattern was also evident in adenocarcinomas from patients who received tamoxifen. Benign endometrium from tamoxifen-treated patients also expressed transforming growth factor-alpha, tumor necrosis factor receptor-II, lactoferrin, and adrenomedullin at levels comparable with those found in proliferative endometrial specimens. CONCLUSION: These data provide further documentation that the uterotropic effects of tamoxifen may be due, at least in part, to the induction of estrogen receptors and progesterone receptors, as well as other genes associated with the proliferative phase. Furthermore, analysis of estrogen receptors, progesterone receptors, and Ki-67 may be useful in identifying postmenopausal individuals on tamoxifen, who are at increased risk for developing endometrial cancer.

Adrenomedullin↗
PubMed2000

Effects of forearm bier block with bretylium on the hemodynamic and metabolic responses to handgrip.

We tested the hypothesis that a reduction in sympathetic tone to exercising forearm muscle would increase blood flow, reduce muscle acidosis, and attenuate reflex responses. Subjects performed a progressive, four-stage rhythmic handgrip protocol before and after forearm bier block with bretylium as forearm blood flow (Doppler) and metabolic (venous effluent metabolite concentration and (31)P-NMR indexes) and autonomic reflex responses (heart rate, blood pressure, and sympathetic nerve traffic) were measured. Bretylium inhibits the release of norepinephrine at the neurovascular junction. Bier block increased blood flow as well as oxygen consumption in the exercising forearm (P < 0.03 and P < 0.02, respectively). However, despite this increase in flow, venous K(+) release and H(+) release were both increased during exercise (P < 0.002 for both indexes). Additionally, minimal muscle pH measured during the first minute of recovery with NMR was lower after bier block (6.41 +/- 0.08 vs. 6.20 +/- 0.06; P < 0.036, simple effects). Meanwhile, reflex effects were unaffected by the bretylium bier block. The results support the conclusion that sympathetic stimulation to muscle during exercise not only limits muscle blood flow but also appears to limit anaerobiosis and H(+) release, presumably through a preferential recruitment of oxidative fibers.

Adult↗
PubMed2000

Efficacy of potential chemopreventive agents on rat colon aberrant crypt formation and progression.

We assessed the effects of 78 potential chemopreventive agents in the F344 rat using two assays in which the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon was the measure of efficacy. In both assays ACF were induced by the carcinogen azoxymethane (AOM) in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last AOM injection, animals were evaluated for the number of aberrant crypts detected in methylene blue stained whole mounts of rat colon. In the initiation phase protocol agents were given during the period of AOM administration, whereas in the post-initiation assay the chemopreventive agent was introduced during the last 4 weeks of an 8 week assay, a time when ACF had progressed to multiple crypt clusters. The agents were derived from a priority listing based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. During the initiation phase carboxyl amidoimidazole, p-chlorphenylacetate, chlorpheniramine maleate, D609, diclofenac, etoperidone, eicosatetraynoic acid, farnesol, ferulic acid, lycopene, meclizine, methionine, phenylhexylisothiocyanate, phenylbutyrate, piroxicam, 9-cis-retinoic acid, S-allylcysteine, taurine, tetracycline and verapamil were strong inhibitors of ACF. During the post-initiation phase aspirin, calcium glucarate, ketoprofen, piroxicam, 9-cis-retinoic acid, retinol and rutin inhibited the outgrowth of ACF into multiple crypt clusters. Based on these data, certain phytochemicals, antihistamines, non-steroidal anti-inflammatory drugs and retinoids show unique preclinical promise for chemoprevention of colon cancer, with the latter two drug classes particularly effective in the post-initiation phase of carcinogenesis.

Animals↗
PubMed1999

Adenosine contributes to hypoxia-induced forearm vasodilation in humans.

In humans, hypoxia leads to increased sympathetic neural outflow to skeletal muscle. However, blood flow increases in the forearm. The mechanism of hypoxia-induced vasodilation is unknown. To test whether hypoxia-induced vasodilation is cholinergically mediated or is due to local release of adenosine, normal subjects were studied before and during acute hypoxia (inspired O(2) 10.5%; approximately 20 min). In experiment I, aminophylline (50-200 microg. min(-1). 100 ml forearm tissue(-1)) was infused into the brachial artery to block adenosine receptors (n = 9). In experiment II, cholinergic vasodilation was blocked by atropine (0.4 mg over 4 min) infused into the brachial artery (n = 8). The responses of forearm blood flow (plethysmography) and forearm vascular resistance to hypoxia in the infused and opposite (control) forearms were compared. During hypoxia (arterial O(2) saturation 77 +/- 2%), minute ventilation and heart rate increased while arterial pressure remained unchanged; forearm blood flow rose by 35 +/- 6% in the control forearm but only by 5 +/- 8% in the aminophylline-treated forearm (P < 0.02). Accordingly, forearm vascular resistance decreased by 29 +/- 5% in the control forearm but only by 9 +/- 6% in the aminophylline-treated forearm (P < 0.02). Atropine did not attenuate forearm vasodilation during hypoxia. These data suggest that adenosine contributes to hypoxia-induced vasodilation, whereas cholinergic vasodilation does not play a role.

Adenosine↗
PubMed1999

Out-patient and home-parenteral antibiotic therapy (OHPAT): evaluation of the impact of one year's experience in Tayside.

OBJECTIVE: An out-patient and home parenteral antibiotic therapy programme for the treatment of suitable infections was developed over a four year period. This paper describes the impact of one year's experience of its implementation on various measures of outcome. DESIGN: Each patient treatment has a full integrated care pathway (ICP) and patient satisfaction questionnaire completed. The ICP documents the clinical progress of the patient and incorporates various measures of quality of care on the 101 number of patients treated from April 1998 to March 1999 are presented here. SETTING: Dundee Teaching Hospitals NHS Trust (now Tayside University Hospitals NHS Trust). SUBJECTS: Patients with a range of infections requiring intravenous antibiotics. MAIN MEASURES: Number of patients treated with various infections, clinical and microbiological outcome, drug and vascular access complication rates, impact on drug costs and in-patient bed days, and measurement of patient satisfaction/quality of life. RESULTS: Patients were treated over a 12 month period. 51.5 per cent had skin & soft tissue infections and 22.8 per cent bone & joint sepsis. 57 per cent of patients received out-patient and 34 per cent self or carer administered home therapy. Ninety-four per cent of patients were cured or improved following treatment. Only 7.5 per cent of patients required an unscheduled admission to hospital. Twelve per cent of patients had some type of vascular device related adverse event (partly due to a faulty batch of lines) and six per cent of patients had a drug related reaction. The additional daily cost of drugs was minimal (< 12 Pounds/day) and more than 1,461 bed days have been saved across the Directorates. The patient satisfaction level was high.

Ambulatory Care↗
PubMed1998

Characterization of Brx, a novel Dbl family member that modulates estrogen receptor action.

Regulation of gene activation by the estrogen receptor (ER) is complex and involves co-regulatory proteins, oncoproteins (such as Fos and Jun), and phosphorylation signaling pathways. Here we report the cloning and initial characterization of a novel protein, Brx, that contains a region of identity to the oncogenic Rho-guanine nucleotide exchange (Rho-GEF) protein Lbc, and a unique region capable of binding to nuclear hormone receptors, including the ER. Western and immunohistochemistry studies showed Brx to be expressed in estrogen-responsive reproductive tissues, including breast ductal epithelium. Brx bound specifically to the ER via an interaction that required distinct regions of ER and Brx. Furthermore, overexpression of Brx in transfection experiments using an estrogen-responsive reporter revealed that Brx augmented gene activation by the ER in an element-specific and ligand-dependent manner. Moreover, activation of ER by Brx could be specifically inhibited by a dominant-negative mutant of Cdc42Hs, but not by dominant negative mutants of RhoA or Rac1. Taken together, these data suggest that Brx represents a novel modular protein that may integrate cytoplasmic signaling pathways involving Rho family GTPases and nuclear hormone receptors.

A Kinase Anchor Proteins↗