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Biomedical subjects

L Bishop

Publications and source records attributed to L Bishop.

At least 19 recordsLinked to original sources
PubMed2003

Outcome of follicular lymphoma grade 3: is anthracycline necessary as front-line therapy?

A grading system (grades 1-3) for follicular lymphoma (FL) is used in the WHO classification for lymphoid malignancies based on the absolute number of centroblasts in the neoplastic follicles. Grade 3 FL is further subdivided into 3a and 3b depending on the presence or absence of centrocytes. A total of 231 patients with FL, referred from 1970 to 2001, were identified from our prospectively maintained database. Original diagnostic materials were available for review on 215 patients and these were reclassified according to the WHO grading system. Follicular lymphoma grades 1, 2 and 3 accounted for 92, 68 and 55 patients, respectively. No significant overall survival (OS) differences were observed among FL grades 1-3 (log rank P=0.25) or between grades 3a and 3b (log rank P=0.20). No significant failure-free survival (FFS) differences were observed among FL grades 1-3 (log rank P=0.72) or between grades 3a and 3b (log rank P=0.11). First-line anthracyclines did not influence OS or FFS (log rank P=0.86, P=0.58, respectively) in patients with FL grade 3. There are long-term survivors among patients with FL grade 3 with a continuing risk of relapse. Anthracyclines did not appear to influence survival or disease relapses when given as front-line therapy in our series. The role of anthracyclines should be further evaluated in large randomised studies.

Adolescent↗
PubMed2003

Rapid access multidisciplinary lymph node diagnostic clinic: analysis of 550 patients.

Lymphadenopathy is common, affecting patients of all ages. The current referral pattern for investigating patients with lymphadenopathy varies widely with no universally practised pathway. Our institution set up a lymph node diagnostic clinic (LNDC) accepting direct referrals from primary care physicians. Details of clinical presentation and investigations were recorded prospectively. Between December 1996 and July 2001, 550 patients were referred (M: 203; F:347). The median age was 40 years (range 14-90). The median time between initial referral and the first clinic visit was 6 days. Of 95 patients diagnosed to have malignant diseases, the median time from the first clinic visit to reaching malignant diagnosis was 15 days. Multivariate logistic regression analysis identified five significant predictors for malignant nodes: male gender (risk ratio (RR)=2.72; 95% confidence interval (CI): 1.63-4.56), increasing age (RR=1.05; 95% CI: 1.04-1.07), white ethnicity (RR=3.01; 95% CI: 1.19-7.6) and sites of lymph nodes: supraclavicular region (RR=3.72; 95% CI: 1.52-9.12) and > or = 2 regions of lymph nodes (RR=6.41; 95% CI: 2.82-14.58). Ultrasound and fine-needle aspiration cytology of palpable lymph nodes were performed in 154 and 289 patients, respectively. An accuracy of 97 and 84% was found, respectively. In conclusion, a multidisciplinary lymph node diagnostic clinic enables a rapid, concerted approach to a common medical problem and patients with malignant diseases were diagnosed in a timely fashion.

Adult↗
PubMed2002

Gastrin-cholecystokinin(B) receptor expression in AGS cells is associated with direct inhibition and indirect stimulation of cell proliferation via paracrine activation of the epidermal growth factor receptor.

BACKGROUND: Activation of the gastrin-cholecystokinin(B) (CCK(B)) receptor stimulates cell proliferation and increases production of ligands for the epidermal growth factor receptor (EGF-R). AIMS: To determine the role of gastrin-CCK(B) activation in stimulation of cell proliferation via paracrine activation of EGF-R. METHODS: AGS cells were transfected with the gastrin-CCK(B) receptor (AGS-G(R) cells) or with green fluorescent protein (AGS-GFP cells). Proliferation was determined by [(3)H] thymidine incorporation, flow cytometry, and cell counting. RESULTS: Gastrin inhibited proliferation of AGS-G(R) cells by delaying entry into S phase. However, when AGS-G(R) cells were cocultured with AGS-GFP cells, gastrin stimulated proliferation of the latter. Immunoneutralisation and pharmacological studies using metalloproteinase and kinase inhibitors indicated that the proliferative response was mediated by paracrine stimulation of EGF-R and activation of the mitogen activated protein kinase pathway through release of heparin binding EGF. CONCLUSIONS: Gastrin can directly inhibit, and indirectly stimulate, proliferation of gastric AGS cells.

Cell Division↗
PubMed2001

Measurement of secretory vesicle pH reveals intravesicular alkalinization by vesicular monoamine transporter type 2 resulting in inhibition of prohormone cleavage.

1. The acidic interior of neuroendocrine secretory vesicles provides both an energy gradient for amine-proton exchangers (VMATs) to concentrate small transmitter molecules, for example catecholamines, and an optimal pH for the prohormone convertases which cleave hormone precursors. There is evidence that VMAT activity modulates prohormone cleavage, but in the absence of measurements of pH in secretory vesicles in intact cells, it has not been possible to establish whether these effects are attributable to raised intravesicular pH due to proton transport through VMATs. 2. Clones were generated of the hamster insulinoma cell line HIT-T15 expressing a pH-sensitive form of green fluorescent protein (GFP-F64L/S65T) targeted to secretory vesicles, with and without co-expression of VMAT2. In order to study prohormone cleavage, further clones were generated that expressed preprogastrin with and without co-expression of VMAT2. 3. Confocal microscopy of GFP fluorescence indicated that the pH in the secretory vesicles was 5.6 in control cells, compared with 6.6 in cells expressing VMAT2; the latter was reduced to 5.8 by the VMAT inhibitor reserpine. 4. Using a pulse-chase labelling protocol, cleavage of 34-residue gastrin (G34) was found to be inhibited by co-expression with VMAT2, and this was reversed by reserpine. Similar effects on vesicle pH and G34 cleavage were produced by ammonium chloride. 5. We conclude that VMAT expression confers the linked abilities to store biogenic amines and modulate secretory vesicle pH over a range influencing prohormone cleavage and therefore determining the identity of regulatory peptide secretory products.

Alkalies↗
PubMed2001

Randomized trial of folic acid supplementation and serum homocysteine levels.

BACKGROUND: Lowering serum homocysteine levels with folic acid is expected to reduce mortality from ischemic heart disease. Homocysteine reduction is known to be maximal at a folic acid dosage of 1 mg/d, but the effect of lower doses (relevant to food fortification) is unclear. METHODS: We randomized 151 patients with ischemic heart disease to 1 of 5 dosages of folic acid (0.2, 0.4, 0.6, 0.8, and 1.0 mg/d) or placebo. Fasting blood samples for serum homocysteine and serum folate analysis were taken initially, after 3 months of supplementation, and 3 months after folic acid use was discontinued. RESULTS: Median serum homocysteine level decreased with increasing folic acid dosage, to a maximum at 0.8 mg of folic acid per day, when the homocysteine reduction (placebo adjusted) was 2.7 micromol/L (23%), similar to the known effect of folic acid dosages of 1 mg/d and above. The higher a person's initial serum homocysteine level, the greater was the response to folic acid, but there were statistically significant reductions regardless of the initial level. Serum folate level increased approximately linearly (5.5 nmol/L for every 0.1 mg of folic acid). Within-person fluctuations over time in serum homocysteine levels, measured in the placebo group, were large compared with the effect of folic acid, indicating that monitoring of the reduction in an individual is impractical. CONCLUSIONS: A dosage of folic acid of 0.8 mg/d appears necessary to achieve the maximum reduction in serum homocysteine level across the range of homocysteine levels in the population. Current US food fortification levels will achieve only a small proportion of the achievable homocysteine reduction.

Adult↗
PubMed2001

Prevention of influenza-induced lung injury in mice overexpressing extracellular superoxide dismutase.

Reactive oxygen and nitrogen species such as superoxide and nitric oxide are released into the extracellular spaces by inflammatory and airway epithelial cells. These molecules may exacerbate lung injury after influenza virus pneumonia. We hypothesized that enhanced expression of extracellular superoxide dismutase (EC SOD) in mouse airways would attenuate the pathological effects of influenza pneumonia. We compared the pathogenic effects of a nonlethal primary infection with mouse-adapted Hong Kong influenza A/68 virus in transgenic (TG) EC SOD mice versus non-TG (wild-type) littermates. Compared with wild-type mice, EC SOD TG mice showed less lung injury and inflammation as measured by significant blunting of interferon-gamma induction, reduced cell count and total protein in bronchoalveolar lavage fluid, reduced levels of lung nitrite/nitrate nitrotyrosine, and markedly reduced lung pathology. These results demonstrate that enhancing EC SOD in the conducting and distal airways of the lung minimizes influenza-induced lung injury by both ameliorating inflammation and attenuating oxidative stress.

Animals↗
PubMed2000

Effects of olestra and sorbitol consumption on objective measures of diarrhea: impact of stool viscosity on common gastrointestinal symptoms.

The aim of this study was to determine the effects of olestra and sorbitol consumption on three accepted objective measures of diarrhea (stool output >250 g/day, liquid/watery stools, bowel movement frequency >3/day), and how stool composition influences reports of common gastrointestinal symptoms. A double-blind, placebo-controlled study compared the effects of sorbitol (40 g/day in candy), a poorly absorbed sugar-alcohol with known osmotic effects, with those of olestra (20 or 40 g/day in potato chips), a nonabsorbed fat, on objective measures of stool composition and GI symptoms. Sixty-six subjects resided on a metabolic ward for 12 days: 2 days lead-in, 4 days baseline, 6 days treatment. Sorbitol 40 g/day resulted in loose/liquid stools within 1-3 h of consumption. In contrast, olestra resulted in a dose-responsive stool softening effect after 2-4 days of consumption. Subjects reported "diarrhea" when mean stool apparent viscosity (peak force (PF), g) decreased from a perceived "normal" (mean +/- SE, 1355 +/- 224 g PF; firm stool) to loose (260 +/- 68 g PF) stool. Mean apparent viscosity of stool during treatment: placebo, 1363 +/- 280 g (firm); olestra 20 g/day 743 +/- 65 g (soft); olestra 40 g/day, 563 +/- 105 g (soft); and sorbitol 40 g/day, 249 +/- 53 g (loose). Of the 1098 stool samples collected, 38% (419/1098) were rated by subjects as "diarrhea," yet only 2% of treatment days (all in the sorbitol treatment group) met commonly accepted criteria for a clinical diarrhea. Sorbitol, but not olestra, increased the severity of abdominal cramping, urgency and nausea compared to placebo. Olestra consumption, at levels far in excess of normal snacking conditions, resulted in a gradual stool softening effect after several days of consumption, did not meet any of the three objective measures of diarrhea, and did not increase GI symptoms. Sorbitol consumption, at only 80% of the dose requiring a "laxative effect" information label, resulted in rapid onset loose/liquid stools and a significant increase in abdominal cramping, urgency and nausea. Overall, subjects categorized stool as "diarrhea" when stool decreased from their perceived "normal," but the vast majority of these reports were not associated with clinically significant diarrhea.

Adolescent↗
PubMed2000

Are 18fluorodeoxyglucose positron emission tomography and magnetic resonance imaging useful in the prediction of relapse in lymphoma residual masses?

Treatment of both Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) frequently results in a residual mass visible radiologically. Such patients may receive radiotherapy unnecessarily because the residual mass may represent benign fibrotic tissue rather than residual active lymphoma. Radiotherapy has been shown to have significant short and more worrying long-term toxicity. Refining the criteria for its use would be a major advance. A number of clinical investigations have been evaluated to more accurately determine the nature of such lesions, including erythrocyte sedimentation rate (ESR), magnetic resonance imaging (MRI) and high-dose gallium-67 scanning (HDGS) but none has proven utility. 18[F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is an imaging technique that has been shown to be useful in distinguishing fibrosis from residual active disease in solid tumours. The aim of this study was to compare FDG PET and MRI in the assessment of residual masses following treatment for lymphoma. Patients with NHL/HD who had a residual mass following chemotherapy were eligible for this study. Patients had a combination of MRI and/or PET. All scans were completed within 5 months of the end of treatment. Patients were followed-up for relapse. 56 patients had an MRI scan, 24 had a PET scan and 22 patients had both investigations. Overall sensitivity and specificity, respectively, were for MRI 45% and 74%, PET 50% and 69%, and PET/MRI concurring 50% and 67%. There was a trend for improved relapse-free survival (RFS) with a negative result of both MRI and PET, but this was not statistically significant. The predictive value for both tests failed to reach statistical significance. Subgroup analysis suggests that PET may be better at predicting relapse in patients with NHL, especially those with masses above the diaphragm. There is no convincing evidence that either MRI or PET or the combination can reliably predict relapse within residual masses after treatment for lymphoma. A negative PET scan however appears to be more informative than a positive result and may well aid clinical decision making. There are a number of factors that may produce false-positive results, including post-treatment inflammatory changes, the sensitivity of the test in the setting of minimal residual disease and the heterogeneity of the histological subtypes studied. A negative PET (or MRI) result in lymphoma residual masses following therapy may negate the necessity for further therapy such as chemotherapy or radiotherapy and their concomitant toxicities.

Adolescent↗
PubMed2000

Effects of wheat bran and Olestra on objective measures of stool and subjective reports of GI symptoms.

OBJECTIVE: The aim of this study was to compare the effects of two nondigested, nonabsorbed dietary components on objective and subjective measures of gastrointestinal (GI) function. METHODS: A placebo-controlled parallel study compared the effects of wheat bran (20 g/day or 40 g/day in cereal), a well-known dietary fiber, with those of olestra (20 g or 40 g/day in potato chips), a nonabsorbed fat, on stool output, stool apparent viscosity (log peak force for extrusion [PF]), stool water content, and GI symptoms. Sixty subjects resided on a metabolic ward for 9 days: 3 days baseline and 6 days treatment. RESULTS: Compared with placebo, consumption of 20 g/day wheat bran for 6 days resulted in a rapid (within 38 h) increase in mean (+/-SE) stool output (placebo, 150 +/- 29 g/day; bran, 246 +/- 35 g/day, p < 0.05), a directional increase in mean stool water content (placebo, 81.2 +/- 0.8%; bran, 83.9 +/- 0.8%), stool water output (placebo, 159 +/- 54 g/day; bran, 238 +/- 30 g/day), and bowel movement frequency (BM/day) (placebo, 2.2 +/- 0.4; bran, 2.6 +/- 0.4), and no stool-softening effect (placebo log PF, 2.9 +/- 0.1 g; bran log PF, 2.9 +/- 0.1 g). Wheat bran 40 g/day results were not significantly different from wheat bran 20 g/day. Compared with placebo, consumption of olestra 20 g/day and 40 g/day for 6 days showed no significant difference in mean stool output (151 +/- 18 g/day and 204 +/- 28 g/day, respectively), mean BM frequency (1.8 +/- 0.2 BM/day and 2.1 +/- 0.3 BM/day, respectively), and stool water output (138 +/- 13 g/day and 184 +/- 31 g/day, respectively), a significant (p < 0.05) decrease in stool water content (75.5 +/- 1.7% and 72.6 +/- 2.2%, respectively), and either no effect on stool apparent viscosity (olestra 20 g/day, mean log PF, 3.0 +/- 0.1 g) or a gradual stool-softening effect beginning study day 6 (olestra 40 g/day, log PF, 2.7 +/- 0.1 g). None of the treatment groups showed a significant increase in GI symptoms compared with placebo. CONCLUSIONS: Consumption of wheat bran in excess of levels in a typical Western diet significantly increased stool output, but did not soften normal-viscosity stool nor result in an increase in common GI symptoms. The observed plateau effect for wheat bran at 40 g/day suggests a maximal mechanical stimulatory effect. Consumption of olestra in excess of usual snacking conditions did not result in a significant increase in stool output or common GI symptoms. At the highest level tested, olestra resulted in a gradual stool-softening effect after several days of consumption.

Adolescent↗
PubMed2000

Investigating lymphadenopathy--report on the first 12 months of the lymph node diagnostic clinic at the Royal Marsden Hospital.

The lymph node diagnostic clinic was set up at the Royal Marsden Hospital to provide a direct access service for general practitioners. In the first year 82 patients were seen. The malignancy pick-up rate was 19.5% which compares very favourably to rates in breast and colorectal clinics. Patient and general practitioner satisfaction with the service was high.

Adolescent↗
PubMed1998

Modulation of the cleavage of the gastrin precursor by prohormone phosphorylation.

BACKGROUND & AIMS: Amidated gastrins are acid secretagogues and growth factors. Their precursor, progastrin, is a growth factor but not a secretagogue. Cleavage of progastrin at Arg94/95 determines the expression of these two alternative patterns of biological activity. We examined the hypothesis that cleavage at Arg94/95 is regulated by phosphorylation of the adjacent Ser96 residue. METHODS: Hamster insulinoma cells were stably transfected with wild-type rat preprogastrin and phosphorylation site mutants; biosynthesis was studied by a pulse-chase protocol. RESULTS: Rates of cleavage at Arg94/95 were increased in Ser96-->Ala compared with wild-type progastrin. Mutation of Glu98 to Ala inhibited incorporation of [32P]phosphate into progastrin and increased the rate of cleavage at Arg94/95. Conversely, mutation of Ser96 to Asp reduced rates of cleavage at Arg94/95. Depletion of calcium stores decreased phosphorylation of Ser96 and increased cleavage at Arg94/95. Modulation of Ser96 phosphorylation also directly influenced the ratio of progastrin-cleavage products (progastrin/CFP; G17Gly/G34Gly) secreted into the medium. CONCLUSIONS: Phosphorylation of progastrin is dependent on calcium stores, determines prohormone cleavage rates, and thereby controls the production of the alternative active products of preprogastrin translation.

Amino Acid Sequence↗
PubMed1996

Effectiveness of erythromycin in the treatment of acute bronchitis.

BACKGROUND: Clinical trials have not shown a consistent benefit of treating bronchitis with antibiotics. Many physicians, however, treat acute bronchitis with antibiotics because of the possibility of Mycoplasma pneumoniae or other pathogens. The objectives of this study were to determine the effectiveness of erythromycin treatment in patients with acute bronchitis and to determine whether a newly developed rapid M pneumoniae antibody test is useful in predicting which patients will respond to therapy. METHODS: We conducted a randomized, double-blind, placebo-controlled clinical trial at three primary care centers in North Carolina. A convenience sample of 140 patients presenting with acute bronchitis were tested for M pneumoniae, 91 of whom were treated with either erythromycin 250 mg four times daily for 10 days or an identical-appearing placebo. RESULTS: Patients treated with erythromycin missed an average of only 0.81 +/- 1.1 days of work compared with 2.16 +/- 3.2 days for placebo-treated patients (P < .02). There were no significant differences in cough, use of cough medicine, general feeling of well-being, or chest congestion between the erythromycin and placebo groups. Twenty-five percent of the patients tested positive for M pneumoniae. There were no differences in response to erythromycin based on whether the patient had a positive test for M pneumoniae. CONCLUSIONS: Erythromycin is effective in significantly reducing lost time from work, but it is not effective in reducing cough or other symptoms in patients with acute bronchitis, regardless of the outcome of the M pneumoniae antibody test.

Acute Disease↗
PubMed1989

Reconstitution of a bacterial periplasmic permease in proteoliposomes and demonstration of ATP hydrolysis concomitant with transport.

The histidine periplasmic permease of Salmonella typhimurium has been partially purified and reconstituted into proteoliposomes. In this in vitro preparation, transport activity is completely dependent on the presence of all four permease proteins (HisJ, HisQ, HisM, and HisP) and on internal ATP. The reconstituted system shows initial rates of transport that are comparable to those obtained with right-side-out membrane vesicles and it establishes a 100-fold concentration gradient for histidine. Proteoliposomes also transport histidine when GTP replaces ATP. Proteoliposomes do not catalyze significant ATP hydrolysis until histidine transport is initiated by addition of substrate along with HisJ, the water-soluble histidine-binding protein. Both initially and throughout the course of substrate transport there is a concomitant hydrolysis of ATP, with an apparent stoichiometry (ATP/histidine) of 5:1. These experiments demonstrate directly that ATP is the source of energy for periplasmic permeases, thus resolving previous controversies on this topic.

ATP-Binding Cassette Transporters↗
PubMed1989

Fine-structure genetic map of the maltose transport operon of Salmonella typhimurium.

We have constructed a fine-structure genetic map of the maltose transport operon in Salmonella typhimurium. We have isolated mal mutants by using indicator plates, penicillin selection, or a proton suicide technique. Mutants were obtained as spontaneous events or were induced by chemical mutagenesis and transposon insertion. Tn10 and Mu d(lac Ap)1 insertion mutations were used to create deletions. Mutations were also obtained in a gene that is equivalent to lamB in Escherichia coli, which codes for the lambda bacteriophage receptor. The gene products in the mutants were characterized by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis and immunoblotting. Our data indicate that the location of this operon on the Salmonella chromosome as well as the gene order and its orientation are the same as those in E. coli. This map will be useful in studying the mechanism of periplasmic transport in S. typhimurium.

ATP-Binding Cassette Transporters↗
PubMed1986

Ultrastructural investigations of cardiomyopathy in the dog.

Eight dogs of the giant breeds with congestive cardiomyopathy were studied at necropsy and samples taken for examination with the electron microscope. Of the 8 dogs, 6 were male. There were 4 Irish Wolfhounds, 2 Great Danes, one Pyrenean and one Saint Bernard. Ages ranged from 6 months to 7 years and if the atypical 6-month-old is removed, the average age was 5 and a third years. Ultrastructural examination of myocardium from abnormal animals showed increases in intermyofibrillar spaces, lipofuscin granules, fat droplets and myelin figures, mitochondrial hyperplasia, disruption of myofibrils and thickening of Z bands. Although all the ultrastructural changes noted were non-specific, the degree of degeneration in cases of congestive cardiomyopathy appeared to be greater than that reported in cases with heart failure caused by other conditions. However, there was no obvious correlation between the length or severity of illness and the degree of ultrastructural damage in dogs with congestive cardiomyopathy. Similarly, there was no correlation between the duration of illness and the severity of the hypertrophy (measured by Z band thickening). As in man, no characteristic features peculiar to this condition were established.

Animals↗
PubMed1986

Monoclonal antibodies to human osteosarcoma-associated antigen(s).

Monoclonal antibodies (MoAbs) against human osteosarcoma cells were obtained by the production and cloning of hybrids resulting from the fusion of mouse myeloma cells P3 X 63Ag8.653 with spleen cells from partially purified, osteosarcoma-associated antigen (OSAA)-immunized BALB/c mice. OSAAs were isolated from the spent culture medium of a human osteosarcoma cell line (TE-85). Five hybrid clones were established and designated as OSA1, OSA2, OSA3, OSA4, and OSA5. OSA1 and OSA2 had similar activity. All 5 MoAbs reacted strongly with most osteosarcoma cell lines and with all osteosarcoma tissues tested but not with 10 tumor cell lines and 2 tumor tissues from other cancers. OSA3, OSA4, and OSA5 cross-reacted with a fibrosarcoma cell line, a colon cell line, and fibrosarcoma, respectively, as well as with a melanoma cell line. None of the MoAbs were reactive with activated normal human peripheral blood mononuclear cells (PBMC). Immunoprecipitation of membrane protein isolated from LM cells and TE-85 cells with the MoAbs OSA1 and OSA2 conjugated with Staphylococcus aureus yielded a molecule with molecular weight of approximately 92,000. No detectable membrane protein was precipitated when 125I-labeled membrane protein from pooled activated human PBMC and tumor cells of other histologic types were used in the immunoprecipitation.

Animals↗
PubMed1980

The use of time-expanded speech in judgments of hypernasality.

Twenty-five samples of various degrees of hypernasal speech were time altered (expanded) to 0%, 125%, 175% of the original time. Inexperienced and experienced student clinicians rated the magnitude of hypernasality and degree of confidence of ratings for each sample in each condition. The results indicate significant differences in ratings of hypernasality for the expansion conditions for both groups. Experienced clinicians showed less variability and higher mean ratings than inexperienced clinicians.

Adolescent↗