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Biomedical subjects

M Shaw

Publications and source records attributed to M Shaw.

At least 163 records · Page 9Linked to original sources
PubMed1987

The effects of polyamine antimetabolites on polyamine-responsive casein kinase activity.

The effects of two inhibitors of ornithine decarboxylase activity, alpha-difluoromethylornithine (DMFO) and (2R,5R) 6-heptyne-2,5 diamine (HDA), and an inhibitor of S-adenosylmethionine decarboxylase, methylglyoxal bis-guanylhydrazone (MGBG), were tested on casein kinase activity and endogenous phosphorylation in the cytosol fractions of mouse thyroid and a rat prostate tumor model, Dunning R 3327 MAT LyLu subline. When tested at 5 mM, spermine, DMFO, HDA, and MGBG stimulated mouse thyroid casein kinase activity by 230%, 14%, 65% and 106%, respectively. Similar responses were observed in prostate tumor cytosol. In mouse thyroid cytosol, spermine stimulates 32P incorporation primarily into 3 proteins (MW: 107, 88, and 56 kDa). At 5 mM, MGBG partially reproduces the effects of spermine; HDA is less effective and DMFO is without effect. Similar effects were observed on 3 proteins in prostate tumor cytosol with molecular weights of 91, 41, and 32 kDa. These data provide additional support for the hypothesis that the observed synergistic inhibitory effect of DMFO and MGBG on cell growth may not be due solely to the inhibition of polyamine biosynthesis. Our findings suggest that MGBG-mediated reduction in the phosphorylation of casein kinase substrate should be considered as one locus of action.

Adenocarcinoma↗
PubMed1987

Inhibition of sensitized leukocyte's in vitro reactivity by circulating immune complexes in prostate cancer.

Circulating immune complexes in the sera of patients with confirmed histological diagnosis of carcinoma of the prostate, were found to interfere in the sensitized leukocyte's in vitro reactivity to prostate cancer associated antigen as evaluated by tube leukocyte adherence inhibition assay, thereby suggesting an inhibitory role of such serum factors in host's anti tumor cell mediated immune responses.

Adenocarcinoma↗
PubMed1987

Social and reproductive characteristics of the first 100 couples treated by in vitro fertilisation programme at National Women's Hospital, Auckland.

Reproductive and social histories of the first 100 patients attending the in vitro fertilisation (IVF) programme at National Women's Hospital, Auckland, have been studied. The average age at first treatment was 31.6 (SD 3.9) for women, and 34.2 (4.6) for men. The couples had been married 7.6 (3.3) years and had experienced 6.7 (3.2) years infertility. It was a second marriage for 16. The husbands had on average a higher social classing than the population (class: number [population]--1:16 (7%), 2:18 (14%), 3:42 (28%), 4:19 (29%), 5:4 (14%), 6:1 (8%); but this bias diminished in the next 159 couples. Nine couples withdrew before their quota of cycles, 7 from stress. Tubal disease was the cause of infertility in 93, but in 69 its origin was untraceable. In 22 it could be attributed to pelvic inflammatory disease (eight associated with IUCDs and 2 with sexually transmitted disease) and in two to sterilisation. Although 59 women had a history of having conceived, only 34 were parous, and only 11 had a child of the current union.

Adult↗
PubMed1987

Subset specificity of antilymhocyte antibodies in systemic lupus erythematosus. II. Preferential reactivity with T4 + cells is associated with relative depletion of autologous T4 + cells.

Using indirect immunofluorescence and flow cytometry, we determined the proportion and number of T3+, T4+, and T8+ cells in the peripheral blood of patients with systemic lupus erythematosus whose sera were positive for cold-reactive antilymphocyte antibodies versus values in patients whose sera were negative for these antibodies. There was a disproportionate reduction in T4+ peripheral lymphocytes when cold-reactive antilymphocyte antibodies preferentially cytotoxic for this subpopulation were present in autologous serum. The decrease in this subset was responsible for a reduction in the T4:T8 ratio; variation in the number and proportion of T8+ cells was insignificant. A similar, but autoantibody-independent, alteration in the T4+ subpopulation was found in patients who were receiving prednisone therapy. A relationship between T cell population abnormalities and systemic lupus erythematosus disease activity, per se, was not observed.

Antibody Specificity↗
PubMed1987

Lymphocyte subsets in urologic cancer patients.

Peripheral blood T lymphocyte subsets were quantitated by monoclonal antibodies in 91 patients with urologic malignancies as well as eight age-matched controls. In general, the presence of cancer and increasing stage were associated with a relative decrease in helper and an increase in suppressor T-cell activity as well as a decreased T4/T8 cell ratio. Therapy in the form of androgen depletion reversed these trends and restored helper and suppressor levels as well as the T4/T8 ratio to control values. In a small subset of sixteen patients surgery had only modest immediate (prostate) and long term (kidney) effects on these parameters.

Androgens↗
PubMed1987

Esophageal electrocardiography in acute cardiac care. Efficacy and diagnostic value of a new technique.

Esophageal electrocardiography can detect atrial electrical activity during tachyarrhythmias when P waves are not evident by surface electrocardiography. However, patient discomfort, the difficulty of accurately interpreting cardiac signals against a background of electrical noise, and the complexity of use have limited widespread application. In this study, esophageal electrocardiography was used in 48 acutely ill patients with a new "pill electrode" system, consisting of a bipolar electrode pair (3 by 20 mm) attached to 0.5 mm diameter Teflon wires contained in a standard gelatin capsule. The capsule with enclosed electrodes was voluntarily swallowed, and the recording electrodes were positioned posterior to the left atrium. A preamplifier system with a low-frequency filter and a standard three-channel electrocardiographic recorder were used. Esophageal "pill" electrocardiographic recordings were made in 48 of 50 eligible study patients (96 percent) with tachyarrhythmias and absent or equivocal atrial activity on surface electrocardiography. In these patients, a high-quality esophageal electrocardiographic recording was obtained within one to 10 minutes with minimal patient discomfort. In 25 of 48 study patients (52 percent), the original diagnosis, based on the surface electrocardiographic recording, was incorrect after review of the esophageal recording. Results of esophageal recording altered management in 19 of 48 (40 percent) patients. This new and simple technique facilitates diagnosis and management of perplexing tachyarrhythmias in acutely ill patients by physicians with minimal training in the technique.

Acute Disease↗
PubMed1987

Circulating molecular variants of growth hormone in childhood.

Human growth hormone (hGH) is known to consist of several molecular forms. We examined the molecular nature of circulating hGH in 18 normal children and compared the resulting patterns to those previously obtained in adults. hGH secretion was stimulated with L-dopa, the hormonal forms were extracted from plasma by immunoadsorbent chromatography, and their molecular nature was analyzed by polyacrylamide gel electrophoresis. Circulating monomeric hGH consisted of 73% hGH22K, 16% hGH20K, and 10% of an acidic hGH from (N alpha-acylated or deamidated hGH). These relative proportions are indistinguishable from those found in the plasma of adults. No age or sex differences in the circulating hGH pattern were found. We conclude that the types and proportions of hGH forms in the blood of normal children are the same as those previously established in adults. These data provide a framework against which children with postulated structurally abnormal ("bioinactive") hGH can be compared.

Adolescent↗
PubMed1987

Pregnancy outcomes after first-trimester vaginitis drug therapy.

Prescription frequencies in the first trimester were compared for miconazole, clotrimazole, nystatin, candicidin, aminacrine compounds, and metronidazole before deliveries involving congenital anomalies versus those not linked to congenital anomalies. Prescriptions before spontaneous abortions were compared with those in the first trimester of deliveries and with those before legal abortions. No statistically significant association was observed with any of these agents for the overall frequency of birth defects or for specific birth defects analyzed (cardiovascular defects, oral clefts, and spina bifida). Two hundred fifty miconazole exposures among 4264 spontaneous abortions, compared with 2236 in the first trimester of 55,736 deliveries, provided an estimated relative risk of 1.4 (95% confidence limits 1.2-1.5). One hundred twelve treatments with clotrimazole among the spontaneous abortions, compared with 1086 among the deliveries, provided a relative risk of 1.4 (95% confidence limits 1.1-1.6). In contrast, large numbers of exposures to nystatin and aminacrine compounds did not show this association, suggesting that spontaneous abortions are caused by the imidazole agents miconazole and clotrimazole rather than the condition being treated. Because many associations were examined without previous hypotheses, and because the data were inadequate to show an elevated risk for clotrimazole when comparing spontaneous with legal abortion exposures, these findings are considered to be a signal for further studies rather than definitive in themselves.

Abnormalities, Drug-Induced↗
PubMed1986

Modulation of IgM anti-lymphocyte antibody-reactive T cell surface antigens in systemic lupus erythematosus.

Cold-reactive lymphocytotoxic autoantibodies are present in the serum of most patients with active systemic lupus erythematosus (SLE) and may be important for the development of the lymphopenia and T cell dysfunction characteristic of this disorder. Neither the mechanisms of autoantibody action in this regard, nor the nature of the relevant T cell membrane target molecules have been defined, however. In the present investigation, preincubation of T cells with SLE serum at 37 degrees C reduced their reactivity with SLE IgM anti-lymphocyte autoantibodies, as demonstrated by indirect immunofluorescence and complement-dependent cytotoxicity. Modulation was restricted to SLE IgM autoantibody-reactive antigen; monoclonal antibody staining of various T cell differentiation and activation antigens remained unchanged. Loss of antigen from the surface membrane was rapid, but transient. A nadir was reached after approximately 120 min of 37 degrees C incubation, followed by essentially complete reexpression of antigen several hours later. Although modulation occurred spontaneously at 37 degrees C in the absence of SLE serum, loss of antigen was enhanced by IgM anti-lymphocyte autoantibodies, despite their low thermal amplitude. Modulation was inhibited by sodium azide, by fixation of cells with paraformaldehyde, and by low incubation temperatures. Colchicine and cytochalasin D had no effect on this process, suggesting that the integrity of the cytoskeleton was not essential. Cycloheximide did not prevent loss of antigen, but inhibited its reexpression. In experiments to determine the fate of modulated antigen, both intracytoplasmic accumulation and shedding from the cell surface were demonstrated. Only shedding was increased by the presence of anti-lymphocyte antibodies, however. These studies delineate modulation of T cell membrane antigen as a new mechanism for anti-lymphocyte autoantibody action in SLE. The occurrence of modulation at physiologic temperatures in vitro suggests that a similar phenomenon of potential relevance to T cell dysfunction may obtain in patients with this disorder.

Antigen-Antibody Reactions↗
PubMed1986

Histopathology of BCG and thiotepa treated bladders.

In an effort to characterize the pathophysiological differences between the modes of action of BCG and thiotepa in the treatment of superficial bladder cancer, normal female rats received weekly intravesical instillations of both agents. The animals were sacrificed and their bladders were examined pathologically to determine if there were histological differences between the cellular infiltrates found in the BCG and thiotepa treated bladders. Mononuclear cells, particularly T-cells, predominated in the BCG treated bladders whereas polymorphonucleated cells predominated in the thiotepa treated bladders suggesting that there may be an immune aspect to the former therapy. The presence of T-cells following BCG therapy suggest a T-cell mediated immune response.

Administration, Intravesical↗
PubMed1986

A role for calmodulin in renal production of 1,25-dihydroxyvitamin D3.

The conversion of circulating 25-hydroxyvitamin D3 (25OHD3) to its active metabolite 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in the renal tubule mitochondrion by the enzyme 25OHD3-1 alpha-hydroxylase is closely regulated in vivo according to the physiological need for calcium and phosphorus. The mechanism by which this regulation is achieved at the cellular level has not been clarified, although a number of lines of evidence suggest that calcium ions (Ca2+) are involved. This study was designed to determine whether calmodulin, the ubiquitous cell protein that binds and mediates many of the regulatory functions of Ca2+, plays a role in the regulation of renal vitamin D metabolism. The calmodulin antagonists trifluoperazine (TFP), Janssen R24571, and the naphthalene sulfonamides W5 and W7 inhibited conversion of 25OHD3 to 1,25-(OH)2D3 by isolated renal tubules from vitamin D-deficient chicks in a dose-dependent manner (ED50: TFP, 12 mumol/liter; R24571, 10 mumol/liter; W7, 30 mumol/liter; W5, 75 mumol/liter). TFP did not inhibit production of the alternative metabolite 24,25-(OH)2D3 by chick renal tubules. In a similar manner, TFP, W7, and W5 inhibited conversion of 25OHD3 to 1,25-(OH)2D3 by isolated energized chick renal mitochondria, with no detrimental effect on mitochondrial respiratory indices. Bovine brain calmodulin in a concentration of 1 X 10(-7) mol/liter enhanced 1,25-(OH)2D3 production by isolated chick renal mitochondria in Ca2+ -containing medium, but not in the absence of Ca2+. Preincubating mitochondria with anticalmodulin antiserum resulted in decreased conversion of 25OHD3 to 1,25-(OH)2D3, an effect that was prevented by exogenous calmodulin. These data support the notion of a role for calmodulin in the Ca2+ -mediated control of renal 1 alpha-hydroxylase activity.

Animals↗
PubMed1985

Failure of acyclovir cream in treatment of recurrent herpes labialis.

A double blind, randomised, crossover placebo controlled trial of 5% acyclovir cream, applied topically five times a day for five days, was carried out in 45 patients with recurrent herpes labialis. These patients had a total of 72 episodes, 34 of which were treated with the 5% acyclovir cream and 38 with placebo cream. Treatment was begun by the patients as soon as possible after the onset of prodromal symptoms. There was no significant clinical benefit from treatment with acyclovir cream compared with placebo cream. The median healing times were nine days with acyclovir cream, 10 days with placebo cream, and 13 days when no treatment was given. The possibility that the 40% propylene glycol cream base alone has a therapeutic effect must therefore be considered.

Acyclovir↗
PubMed1985

Surface antigen specificity of cold-reactive IgM antilymphocyte antibodies in systemic lupus erythematosus.

Monoclonal antibodies to known surface antigens on B cells and on resting and activated T cells of various types were used in several approaches to examine the specificity of IgM antilymphocyte antibodies in systemic lupus erythematosus (SLE). Surface determinants that were sought included: T3, T11, Leu-1, Leu-8 (pan-T); T4, T8 (T subset); beta 2-microglobulin (beta 2m); L243, Leu-10 (DR and DS/DC framework, respectively); anti-Tac (interleukin-2 receptor); 5E9 (transferrin receptor); and 4F2, AA1 (other activation antigens). The first strategy was based on inhibition of rosette formation between mouse monoclonal antibody-coated targets and anti-mouse IgG-coated erythrocytes by SLE sera, either directly at 4 degrees C or after modulation of IgM antilymphocyte antibody-reactive target cell antigen at 37 degrees C. Significant rosette inhibition, defined as greater than 2 standard deviations from the mean value for 10 control sera, was seen only for beta 2m (13 of 20 SLE sera were positive; inhibition = 15-58%). Next, relative fluorescence intensity of lymphocyte staining by monoclonal antibodies was assessed by flow microfluorometry after preincubation of cells with SLE serum at 4 degrees C or after modulation of SLE antibody-reactive antigen. Modulation markedly reduced or eliminated SLE antilymphocyte antibody IgM staining. Except for beta 2m, neither cold nor warm temperature preincubations altered the relative fluorescence intensity for the known surface antigens. These data confirm anti-beta 2m as a common antibody specificity in SLE and suggest that antilymphocyte antibodies in this disorder are not directed to Ia or to certain other defined lymphocyte antigens of functional interest.

Antibody Specificity↗