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Biomedical subjects

S Murray

Publications and source records attributed to S Murray.

At least 91 records · Page 5Linked to original sources
PubMed1998

The importance of the histologic grade of invasive breast carcinoma and response to chemotherapy.

BACKGROUND: Histologic grade is well recognized for its prognostic significance in cases of primary operable invasive breast carcinoma; however, the majority of studies in which grade has been assessed have been based on single-center trials. In addition, the role of grade in predicting response to chemotherapy has not been examined in many previous studies. METHODS: The authors assessed the value of Nottingham histologic grade (NHG) in a group of 465 patients enrolled in a multicenter, randomized International Breast Cancer Study Group clinical trial of adjuvant chemotherapy for patients with lymph node (LN) positive and LN negative primary breast carcinoma (formerly named Ludwig Trial V). RESULTS: NHG was a predictor of overall survival for both LN negative and LN positive patients (P=0.045 and P < 0.001, respectively). NHG was associated with a poorer prognosis for both LN positive and LN negative patients, with hazard ratios of 1.651 (P < 0.001) and 1.437 (P=0.045), respectively, for an increase of one grade. Among LN negative patients, this survival disadvantage was observed only for those who received perioperative chemotherapy. For LN positive patients, an increase of one grade resulted in a significant overall survival disadvantage regardless of whether prolonged or perioperative chemotherapy was given. For LN negative patients grouped by grade, there was no observed difference in overall or disease free survival according to whether perioperative chemotherapy or no adjuvant therapy was given. However, LN positive patients with Grade 3 tumors had a significantly greater overall and disease free survival benefit from prolonged chemotherapy than from perioperative chemotherapy (P=0.016 and P=0.013, respectively); LN positive patients with Grade 1 or 2 disease in both treatment arms had comparable overall and disease free survival. A strong correlation between the previously utilized Bloom-Richardson grading system (BRG) and NHG was observed (P < 0.001 and kappa=82%) and no apparent differences in overall and disease free survival were observed between the two systems. NHG did, however, identify a greater proportion of tumors as Grade 1, and BRG identified a greater proportion of breast carcinomas as Grade 3. CONCLUSIONS: This multicenter clinical study confirms the value of histologic grade, and the authors propose that this technique be used to identify Grade 3, LN positive patients who will benefit from prolonged rather than perioperative chemotherapy.

Antimetabolites, Antineoplastic↗
PubMed1998

Simplified method of identifying severe combined immunodeficient (SCID) mice versus non-SCID mice by flow cytometric analysis of peripheral blood.

Several studies have utilized simple breeding strategies to create new immunodeficient mouse strains from severe combined immunodeficient (SCID) mice and non-SCID mice with secondary traits in order to evaluate the involvement of lymphocytes and immune responses in a variety of processes. We utilized a breeding strategy with C.B-17scid/scid (SCID) (H-2d) mice and SJL (H-2s) mice to generate immunodeficient mice that were histocompatible with the inbred SJL strain (H-2s) in order to evaluate the role of histocompatible recipient lymphocytes in adoptively transferred autoimmune disease mediated by SJL T lymphocytes. [SCID x SJL]F1 mice (heterozygous for H-2 loci and heterozygous for the SCID mutation) were backcrossed with SCID mice and the resulting offspring expressed a variety of phenotypes, including SCID or non-SCID and H-2s/H-2d or H-2d/H-2d. In order to screen offspring for the desired phenotype (SCID, H-2s), a flow cytometric method utilizing forward- and side-scatter parameters of peripheral blood cells was used to distinguish SCID from non-SCID animals. This method simplified the screening process and was as reliable as anti-CD3 fluorescent monoclonal antibody staining for detecting the presence (non-SCID) or absence (SCID) of T lymphocytes in peripheral blood.

Animals↗
PubMed1998

Cerebrospinal fluid epinephrine in Alzheimer's disease and normal aging.

Central nervous system (CNS) adrenergic systems are involved in regulation of behavior and blood pressure. The effects of Alzheimer's disease (AD) and normal aging on resting CNS adrenergic activity were estimated by measuring cerebrospinal fluid (CSF) epinephrine (EPI) concentrations in 74 persons with AD, 42 cognitively normal healthy older persons, and 54 healthy young persons. The responsiveness of CSF EPI to the alpha-2 adrenergic antagonist yohimbine and the alpha-2 adrenergic agonist clonidine was measured in smaller subject groups. Resting CSF EPI was higher in AD than in older or young subjects, and increased with dementia severity in AD subjects. There was no relationship between resting CSF EPI and blood pressure. CSF EPI increased following yohimbine in AD and older subjects but not in young subjects. CSF EPI was unaffected by clonidine in all subject groups. The agitation increase following yohimbine was substantially greater in AD subjects than in older or young subjects. CNS adrenergic activity seems increased in AD, may further increase as AD progresses, and may be involved in the pathophysiology of agitation.

Adrenergic alpha-Agonists↗
PubMed1998

Association of atherogenic low-density lipoprotein subfractions with carotid atherosclerosis.

Patients with carotid atherosclerosis are at increased risk of both stroke and ischaemic heart disease. Low-density lipoprotein (LDL) is a heterogeneous group of particles, with small, dense particles being more atherogenic. We studied 79 patients (51 men, mean +/- SD age 62.4 +/- 11.7 years) referred for Doppler ultrasound assessment of the carotid arteries. Evidence of carotid atherosclerosis, defined as the presence of atherosclerotic plaque, stenosis or occlusion in one or more of the six carotid artery segments examined, was found in 44 patients (56%). LDL subfractions were analysed by disc polyacrylamide gel electrophoresis with prior ultracentrifugation of serum to remove chylomicrons. This method produces a LDL score; the higher the score, the greater the proportion of the more atherogenic LDL subfractions. Mean LDL score was significantly higher in diseased patients (mean +/- SD, 1.56 +/- 0.61) than the normal group (1.26 +/- 0.65) (t = 2.12, p = 0.037). There was no significant association between LDL score and severity of carotid artery stenosis. Age (adjusted odds ratio 1.09, 95% CI 1.03-1.15) and smoking history (2.09, 95% CI 1.10-3.98) predicted carotid atherosclerosis in logistic regression analysis, with LDL score achieving borderline significance (2.20, 95% CI 0.91-5.29). Small, dense LDL subfractions are associated with carotid atherosclerosis and may be a modifiable risk factor for stroke as well as ischaemic heart disease.

Age Factors↗
PubMed1997

Delta and kappa opioid receptors are differentially regulated by dynamin-dependent endocytosis when activated by the same alkaloid agonist.

Many alkaloid drugs used as analgesics activate multiple opioid receptors. Mechanisms that distinguish the actions of these drugs on the regulation of individual micro, delta, and kappa receptors are not understood. We have observed that individual cloned opioid receptors differ significantly in their regulation by rapid endocytosis in the presence of alkaloid drug etorphine, a potent agonist of mu, delta, and kappa opioid receptors. Internalization of epitope-tagged delta opioid receptors from the plasma membrane is detectable within 10 min in the presence of etorphine. In contrast, kappa receptors expressed in the same cells remain in the plasma membrane and are not internalized for >/=60 min, even when cells are exposed to saturating concentrations of etorphine. The rapid internalization of delta receptors is specifically inhibited in cells expressing K44E mutant dynamin I, suggesting that type-specific internalization of opioid receptors is mediated by clathrin-coated pits. Examination of a series of chimeric mutant kappa/delta receptors indicates that at least two receptor domains, including the highly divergent carboxyl-terminal cytoplasmic tail, determine the type specificity of this endocytic mechanism. We conclude that structurally homologous opioid receptors are differentially sorted by clathrin-mediated endocytosis following activation by the same agonist ligand. These studies identify a fundamental mechanism of receptor regulation mediating type-specific effects of analgesic drugs that activate more than one type of opioid receptor.

Adenylyl Cyclases↗
PubMed1997

Mental health. Careering around.

An orientation exercise provided a structured, supervised induction for practice based community psychiatric nurses. The exercise also provided community perspectives on need. The same process could be used for other new primary healthcare workers.

Career Mobility↗
PubMed1997

Analysis of terfenadine in human plasma using microbore high-performace liquid chromatography-electrospray ionisation mass spectrometry.

An assay based on combined microbore high-performance liquid chromatography-positive ion electrospray ionisation mass spectrometry with selected ion recording has been developed for the measurement of the antihistamine drug terfenadine in human plasma. A deuterated analogue of terfenadine was synthesised for use as an internal standard and extraction of terfenadine was carried out on C18 solid phase extraction columns. The limit of detection of terfenadine in plasma is 0.1 ng/ml and the intra-assay coefficient of variation at 1 ng/ml is 10.1%. Plasma concentrations of terfenadine measured in six normal subjects following a 120 mg oral dose are reported.

Anti-Allergic Agents↗
PubMed1997

Assessing human risk to heterocyclic amines.

Heterocyclic amines such as MeIQx and PhIP are potent genotoxic chemicals which are formed at part per billion levels when meat is cooked. Using assays based on gas chromatography/mass spectrometry with stable isotope labelled analogues as internal standards we have demonstrated MeIQx and PhIP, are efficiently absorbed into the systemic circulation after ingestion of fried beef. Using a potent and selective inhibitor of human CYP1A2, furafylline, we have shown that N-hydroxylation catalysed by this enzyme is the major pathway of metabolism of MeIQx and PhIP and is solely responsible for their oxidation to mutagenic species. This is in contrast to the situation in laboratory animals in which both activation by N-hydroxylation and deactivation by C-oxidation occurs. When furafylline was administered to human volunteers before ingestion of fried beef, we showed that > 90% of MeIQx and approximately 70% of PhIP elimination could be inhibited, demonstrating the extent to which activation occurred in man. MeIQx is a very powerful mutagen in bacterial assays whereas PhIP is a more potent mammalian cell mutagen. Using a mammalian cell target gene, hprt, we have shown that PhIP induces a characteristic mutational 'fingerprint' which is identical to that detected in the Apc gene of 5/8 colonic tumours induced by PhIP in rats. These studies support a biological association between HA exposure and diet-related tumours but emphasise that information obtained from animal studies does not always reflect the situation in humans.

Animals↗
PubMed1997

Tumor growth, weight loss and cytokines in SCID mice.

It has been proposed that immunoregulatory cytokines play a role in the onset and development of cancer cachexia, although evidence supporting this theory remains inconclusive. In the present study, SCID mice were implanted with one of two tumor cell lines known to induce weight loss in rats. Growth of the Morris 7777 hepatoma was associated with weight loss as well as increased levels of tumor necrosis factor and interleukins 1 and 6 in spleen cells of tumor-bearing mice. Growth of the MCA sarcoma did not induce weight loss, nor did it increase cytokine expression in spleen cells of tumor-bearing mice. We conclude that increased cytokine expression is associated with weight loss in tumor-bearing SCID mice, and immune activation for cytokine expression does not require the presence of T or B cells.

Animals↗
PubMed1997

Arginine-specific mono(ADP-ribosyl)transferase activity in human neutrophil polymorphs. A possible link with the assembly of filamentous actin and chemotaxis.

Mono(ADP-ribosyl)transferase activity has been detected on the external surface of human polymorphonuclear neutrophil leucocytes (PMNs). The corresponding cDNA has been cloned and shown to be identical to that derived from human skeletal muscle. Our results suggest that mono(ADP-ribosyl)transferase is involved in the transduction pathway mediating (i) receptor-dependent re-alignment of cytoskeletal actin and (ii) chemotaxis of PMNs.

ADP Ribose Transferases↗
PubMed1997

The cardiac effects of terfenadine after inhibition of its metabolism by grapefruit juice.

OBJECTIVE: To determine whether the pharmacokinetics and electrocardiographic pharmacodynamics of terfenadine are affected by the concomitant administration of grapefruit juice. METHODS: Six healthy volunteers were recruited for a balanced cross-over study. Each volunteer received 120 mg terfenadine 30 min after drinking 300 ml of either water or freshly squeezed grapefruit juice. The alternative treatment was administered on the second study day 2 weeks later. Measurements of the area under the terfenadine plasma concentration-time curve (AUC), maximum terfenadine concentration (Cmax) and the time to maximum concentration (tmax) were made, and the corrected QT (QTc) interval was measured from the surface electrocardiogram. RESULTS: Terfenadine was quantifiable in plasma in all 6 subjects on both study days for up to 24 h post-dosing. The AUC of terfenadine was significantly increased by concomitant grapefruit administration (median values 40.6 vs 16.3 ng.ml-1.h), as was the Cmax (median values 7.2 vs 2.1 ng.ml-1). The tmax was not significantly increased and there was no significant change in the median QTc interval despite the increased terfenadine levels. The 95% confidence interval for the difference in the change in QTc interval at Cmax was -13 to +38 ms. CONCLUSION: Administration of grapefruit juice concomitantly with terfenadine may lead to an increase in terfenadine bioavailability, but the increase observed in this study did not lead to significant cardiotoxicity in normal subjects. However, this does not exclude the risk of cardiotoxicity in high-risk subjects given greater doses of grapefruit juice over longer periods of time.

Adult↗
PubMed1997

The relationship between gastroesophageal reflux disease and its complications with Barrett's esophagus.

BACKGROUND: Barrett's esophagus is a condition in which the stratified squamous epithelium of the esophagus is replaced by a columnar epithelium with malignant potential. Chronic gastroesophageal reflux disease (GERD) is accepted as the primary risk factor for the development of Barrett's esophagus, but only a small fraction of individuals with GERD develop Barrett's esophagus. We sought to identify factors that increase the risk of Barrett's esophagus in those with GERD. OBJECTIVE: The objective of this matched case-control study was to investigate possible clinical risk factors for Barrett's esophagus. METHODS: The study was based on 79 case patients with Barrett's esophagus and 180 control patients. Each case patient was matched to one control patient whose indication for endoscopy was GERD and one control patient who underwent endoscopy for other indications. The case and control patients were matched for age, gender, and race. All patients underwent endoscopy at Duke University Medical Center, Durham, NC, between July 1992 and August 1994. RESULTS: On average, patients with Barrett's esophagus developed reflux symptoms at an earlier age than age- and gender-matched control patients and also had a longer duration of symptoms. Complications of reflux, including esophagitis, stricture, and ulceration, were reported significantly more frequently in the group of case patients than either group of control patients. CONCLUSIONS: The results of this pilot study indicate that age of onset, duration of symptoms, and complications of GERD may be markers of increased risk of Barrett's esophagus.

Age of Onset↗
PubMed1997

Zinc toxicosis in a Celebes ape (Macaca nigra) following ingestion of pennies.

An adult Celebes ape (Macaca nigra) was presented for a routine yearly evaluation. Abdominal radiographs revealed four radiodense metallic foreign objects resembling coins within the gastrointestinal tract. Hematologic abnormalities included a mild nonregenerative anemia and a mild leukocytosis, and the biochemical profile reflected renal dysfunction. Serum zinc levels were elevated. The animal was denied food for 24 hr in preparation for the endoscopic removal of the foreign objects. During this period, two partially eroded pennies were passed in the feces. Endoscopy was temporarily postponed, and the animal was offered food. Two days later a third penny was passed. When the fourth coin did not pass within the next 2 days, the animal was once again denied food, and the fourth coin was passed within 24 hr. Because of the temporal association between the fasting cycles and the passage of the coins, a causal relationship is suggested. Following the passage of all coins, serum zinc levels decreased, and hematologic and serum biochemical abnormalities improved. Six months later, all abnormalities had resolved.

Animals↗
PubMed1996

Arginine-specific mono(ADP-ribosyl)transferase activity on the surface of human polymorphonuclear neutrophil leucocytes.

An Arg-specific mono(ADP-ribosyl)transferase activity on the surface of human polymorphonuclear neutrophil leucocytes (PMNs) was confirmed by the use of diethylamino-(benzylidineamino)guanidine (DEA-BAG) as an ADP-ribose acceptor. Two separate HPLC systems were used to separate ADP-ribosyl-DEA-BAG from reaction mixtures, and its presence was confirmed by electrospray mass spectrometry. ADP-ribosyl-DEA-BAG was produced in the presence of PMNs, but not in their absence. Incubation of DEA-BAG with ADP-ribose (0.1-10 mM) did not yield ADP-ribosyl-DEA-BAG, which indicates that ADP-ribosyl-DEA-BAG formed in the presence of PMNs was not simply a product of a reaction between DEA-BAG and free ADP-ribose, due possibly to the hydrolysis of NAD+ by an NAD+ glycohydrolase. The assay of mono(ADP-ribosyl)transferase with agmatine as a substrate was modified for intact PMNs, and the activity was found to be approx. 50-fold lower than that in rabbit cardiac membranes. The Km of the enzyme for NAD+ was 100.1 30.4 microM and the Vmax 1.4 0.2 pmol of ADP-ribosylagmatine/h per 10(6) cells. The enzyme is likely to be linked to the cell surface via a glycosylphosphatidylinositol anchor, since incubation of intact PMNs with phosphoinositol-specific phospholipase C (PI-PLC) led to a 98% decrease in mono(ADP-ribosyl)transferase activity in the cells. Cell surface proteins were labelled after exposure of intact PMNs to [32P]NAD+. Their molecular masses were 79, 67, 46, 36 and 26 kDa. The time course for labelling was non-linear under these conditions over a period of 4 h. The labelled products were identified as mono(ADP-ribosyl)ated proteins by hydrolysis with snake venom phosphodiesterase to yield 5'-AMP.

ADP Ribose Transferases↗
PubMed1996

Rhinovirus enters but does not replicate inside monocytes and airway macrophages.

Potential interactions between rhinovirus (RV) and both the airway macrophage and its precursor cell, the blood monocyte, were investigated in terms of direct binding, intracellular replication, cell survival, and cytokine production. When HeLa cell suspensions are inoculated with RV as a positive control, virus titer increases by 100-fold in the first 24 h, confirming intracellular replication. In contrast, RV titer in monocyte and macrophage suspensions steadily decreased. Despite a lack of productive RV replication, cell-associated RV RNA was detectable using a biotin-labeled cDNA probe as early as 6 h after inoculation. Direct binding of RV16 to macrophages was confirmed using radiolabeled virus, although preincubation with anti-ICAM-1 mAb did not block this interaction. Synthesis of RV RNA, as indicated by [3H]uridine incorporation in actinomycin D-treated cells, was detected in HeLa cells but not macrophages, suggesting that the viral RNA detected inside macrophages was from input virus and was not newly synthesized. RV inoculation did not adversely affect monocyte or macrophage viability. Finally, RV caused macrophage activation, as indicated by the induction of TNF-alpha secretion. These in vitro findings suggest that macrophages interact with major group RV in vivo, and raise the possibility that there is a second cellular receptor for these viruses. Furthermore, macrophages do not serve as permissive host cells during in vivo RV infection, but instead may be active participants in anti-RV immunity and RV-induced airway inflammation.

Antibodies, Monoclonal↗