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Biomedical subjects

S R Wilson

Publications and source records attributed to S R Wilson.

At least 163 records · Page 9Linked to original sources
PubMed1984

Selective effects of the genetic background and ethanol on the alcohol dehydrogenase polymorphism in Drosophila melanogaster.

Eight freshly caught Australasian mass collections ranging in Adh F frequency from 4 to 96 per cent were each divided into eight selection lines. Two selection lines from each base population were put on one of four types of medium-standard food supplemented with 0 per cent, 3 per cent, 6 per cent or 9 per cent ethanol. After 30 generations the tolerance of 6 per cent and 9 per cent selection lines on a test dose of 9 per cent ethanol was greater than that of the 0 per cent lines on this dose. The tolerance of the 3 per cent lines on this dose was less than that of the 0 per cent lines. There were no significant differences in the tolerance responses across the eight base populations but in only one did Adh frequencies diverge among the four ethanol selection environments: F frequencies in the Brisbane 9 per cent lines were higher than in the Brisbane 0 per cent, 3 per cent and 6 per cent lines. Although the selection affecting Adh did not generally differ among the four selection environments, it differed highly significantly among the eight base populations. The equilibrium F frequencies predicted from the maximum likelihood estimates of the selection coefficients were in close agreement with the frequencies observed in the original collections. The only aspect of the coefficients which was consistent across base populations was FS heterozygote superiority.

Alcohol Oxidoreductases↗
PubMed1984

Sonographic evaluation of hepatic abscesses.

A retrospective study of 37 patients with liver abscesses evaluated by diagnostic ultrasonography suggests that an abscess evolves from a small solid inflammatory focus to a well defined fluid-filled cavity over a variable time interval. Initial scans on six patients revealed a single nonspecific poorly defined solid liver mass. Following diagnostic aspiration, four of these patients were successfully treated with antibiotics alone. Two other patients with initial subtle solid masses went on to develop a more classical cystic abscess cavity with time. The remaining 31 patients had abscess which appeared initially as fluid-filled or cystic masses with variable internal echogenicity, through transmission, and margination. One-half of the patients presented acutely with fever, right upper quadrant pain, and chills. The remaining patients had a more variable indolent presentation with five patients having a course lasting over one month. Eleven patients had associated biliary tract disease. Drainage was performed on 33 patients, 30 by open surgery and three percutaneously with ultrasound guidance. There were no deaths related to sepsis in our series.

Adolescent↗
PubMed1984

Psoas disease causing a characteristic change in the ultrasonographic appearance of the psoas compartment.

Twenty patients with ultrasonographic evidence of disease involving the psoas compartment were analysed retrospectively. The abnormality found was a mass lesion in the psoas muscle with increased or decreased echogenicity and a characteristic loss of the normal appearance of striated homogeneous bundles. Those examined included eight patients with abscesses, six with hematomas and six with tumor infiltration. All the abscesses were echopoor and showed absence of the normal appearance of the muscle. Such findings are non-specific because of the similar appearance of non-organized hematomas or lymphomatous infiltration. Organized hematomas and primary retroperitoneal tumors were echogenic but with loss of the normal appearance. Ultrasound guided needle aspiration is sometimes necessary to complete the diagnosis and may be a definitive strategy. We recommend ultrasonography for use in detecting psoas disease when appropriate clinical signs are present.

Abscess↗
PubMed1984

Ultrasonographic interpretation of physiological changes in the female pelvis.

Ultrasonographic assessment of the pelvis of women of child bearing age requires an appreciation of the physiologic changes that occur during the menstrual cycle. A prospective study on 15 women was done between July and December 1981. Pre-ovulatory (late proliferative phase), post-ovulatory (early secretory phase), and premenstrual (late secretory phase) scans were performed during each menstrual cycle. Basal body temperatures were used to determine the time of ovulation. The appearance of the ovaries, uterus, and pouch of Douglas was documented. The purpose of this study was to assess if the developmental stage of a follicle can be determined by observing the presence or absence of ovarian cysts and noting their change with time, to determine if free fluid is an indicator of follicle rupture, and to assess changes in the endometrium. We concluded that one or more small or large ovarian cysts on a single scan is an unreliable predictor of the stage of follicular development; that serial scanning is the preferred method for following physiologic follicular change; that free fluid is associated with ovulation and is commonly seen on post-ovulatory scans; and that while a thick and echogenic endometrium is normal in the premenstrual phase, in most people a more subtle progressive thickening and increased reflectivity is observed.

Endometrium↗
PubMed1983

Insulin activates the plasma-membrane and dense-vesicle cyclic AMP phosphodiesterase in hepatocytes by distinct routes.

Insulin elicits the activation of two distinct membrane-bound cyclic AMP phosphodiesterases when incubated at 37 degrees C for 5 min with intact hepatocytes: the 'dense-vesicle' enzyme and the peripheral-plasma-membrane enzyme. In hepatocytes the lysosomotropic agents chloroquine, methylamine and NH4Cl, as well as intracellular ATP depletion elicited by fructose or incubation with insulin at 22 degrees C, blocks selectively the activation of the 'dense-vesicle' enzyme. Incubation of hepatocytes with bacitracin, leupeptin and a variety of proteinase inhibitors failed to affect insulin's activation of these two cyclic AMP phosphodiesterases by distinct routes. It is suggested that activation of the 'dense-vesicle' enzyme occurs through a pathway triggered by the endocytosis, processing and recycling of the insulin receptor. This might involve the delivery, with subsequent activation, of a latent phosphodiesterase into this fraction.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1983

Heterogeneity of cyclic nucleotide phosphodiesterases in liver endoplasmic reticulum.

A microsomal fraction from rat liver was subfractionated into three rough endoplasmic reticulum fractions RIII, RII and RI, together with a smooth endoplasmic reticulum plus Golgi fraction. Cyclic nucleotide phosphodiesterase activity was found in all fractions. Subsequently it was shown that Golgi fractions were essentially devoid of cyclic AMP phosphodiesterase activity and the activity resided in the smooth endoplasmic reticulum fraction. The activity of the endoplasmic reticulum constituted some 20% of the homogenate activity, with the major fraction of this being associated with the RII fraction and the least with the RI fraction. With the exception of the activity of the RI fraction, which was a peripheral enzyme, all of the other enzyme activities were integral, requiring detergent or repeated freeze-thawing to effect solubilization. All of the activities appeared to be exposed at the external surface of the endoplasmic reticulum, as they were inactivated by trypsin under conditions where glucose 6-phosphatase was not. All of these activities displayed distinct sensitivities to both thermal and trypsin inactivation, yielding activity decays consistent with a single enzyme species being present in each case. The freeze-thaw-solubilized enzymes yielded single symmetrical peaks on sucrose-density-gradient centrifugation and polyacrylamide-gel electrophoresis. The sedimentation coefficients for the enzymes in the smooth-endoplasmic-reticulum-plus-Golgi, RIII, RII and RI fractions were 3.2S, 4.2S, 4.5S and 4.5S respectively. Whereas the activity in the smooth-endoplasmic-reticulum-plus-Golgi fraction exhibited normal Michaelis kinetics, those in the other fractions yielded kinetics indicative of apparent negative co-operativity. All of the enzymes exhibited low Km values towards cyclic AMP. The enzymes did not appear to be regulated by Ca2+ or calmodulin. ZnCl2 was found to be a potent non-competitive inhibitor of the enzyme in all fractions. NaF was a weak non-competitive inhibitor. The bilayer fluidizing agent benzyl alcohol exerted dissimilar effects on the enzyme activities. It is concluded that the endoplasmic reticulum displays lateral heterogeneity, with single, rather distinct, cyclic AMP phosphodiesterases being found in the different fractions.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1983

Proteolytic activation and solubilization of endoplasmic-reticulum cyclic AMP phosphodiesterase activity.

Dithiothreitol led to the activation and solubilization of the cyclic nucleotide phosphodiesterase activities associated with the smooth and various rough subfractions of rat liver endoplasmic reticulum. The activity in each of the subfractions exhibited somewhat different time courses, and sensitivities to dithiothreitol concentration, in respect of their solubilization and activation. Both activation and solubilization by dithiothreitol could be blocked by either thiol proteinase inhibitors or excess bovine serum albumin. Freeze-thaw solubilization was not blocked by the thiol proteinase inhibitor antipain and did not lead to the activation of the enzyme. After dithiothreitol-induced solubilization, all of the enzymes exhibited non-linear Lineweaver-Burk plots indicative of apparent negative co-operativity. In contrast, after freeze-thaw solubilization the enzyme in the smooth-endoplasmic-reticulum-plus-Golgi fraction still obeys Michaelis kinetics, as does the membrane-bound enzyme. It is possible to mimic the action of dithiothreitol in solubilizing and activating the enzyme by limited proteolysis with trypsin. Triton X-100 is highly efficient at solubilizing these enzymes, yet has little effect on their activities. Charged detergents exhibit highly selective effects on the enzymes as regards their solubilization and activity expressed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1983

Search for a red cell enzyme or serum protein marker in amyotrophic lateral sclerosis and parkinsonism-dementia of Guam.

Frequency distributions were determined for 24 red cell enzyme and four serum protein systems, in an attempt to identify a genetic marker associated with either amyotrophic lateral sclerosis (ALS) or parkinsonism-dementia (PD), two progressive and fatal neurological disorders of unknown cause found with unusually high incidence among the Chamorros of Guam and the Northern Mariana Islands. No striking associations were identified between either disorder and any of the gene markers tested. Thus, no genetic cause is known for either disease; local environmental factors are most likely involved in pathogenesis.

Amyotrophic Lateral Sclerosis↗
PubMed1983

Functional antibacterial activity of a human intravenous immunoglobulin preparation: in vitro and in vivo studies.

The functional antibacterial activity of an intravenous immunoglobulin preparation (Swiss Red Cross Immunoglobulin, SRK-Ig) was tested both in vitro and in vivo. Using type III group B streptococci as a model system, the intravenous immunoglobulin preparation was shown to enhance phagocytosis and killing of the bacteria by human neutrophils. There was good activity to several type III strains, and for efficient opsonization both antibody and complement were required. In an animal model of neonatal group B streptococcal sepsis, passively administered immunoglobulin enhanced survival with 27/37 (73%) treated animals surviving compared to only 3/16 (19%) controls. These studies demonstrate that the intravenous immunoglobulin preparation SRK-Ig has retained functional activity and may have potential value for prophylaxis or therapy of certain bacteria infections.

Animals↗
PubMed1982

Antibacterial activity of a human monoclonal antibody to haemophilus influenzae type B capsular polysaccharide.

Human splenic lymphocytes were fused with a new mutant human myeloma cell line (HFB-1) to produce hybridomas that secrete human monoclonal antibodies. A cloned hybridoma line was selected that secretes IgG antibodies reactive with Haemophilus influenzae type b polyribosylribitolphosphate (PRP) capsular polysaccharide. This human monoclonal antibody was active in an in-vitro neutrophil-mediated bactericidal assay, and provided significant protection in an animal model of H. influenzae type b disease. Human monoclonal antibody to H. influenzae type b may have prophylactic value in man, particularly in infants who do not produce protective antibody after active immunisation with PRP.

Antibodies, Monoclonal↗
PubMed1982

Functional characteristics of a modified immunoglobulin preparation for intravenous administration: summary of studies of opsonic and protective activity against group B streptococci.

Group B streptococci (GBS) remains a major cause of morbidity and mortality in newborn babies, despite antibiotic therapy, Recent studies suggest that phagocytosis and killing of GBS is ineffective due to a deficiency in anti-GBS antibody. Using an opsonophagocytic bacterial assay and a suckling rat model of GBS sepsis, we analyzed a modified human immunoglobulin for opsonic and protective antibody. Immune globulin (IGIV) prepared for intravenous use (Gamimune, Cutter Laboratories, Inc.) was highly protective in this experimental GBS model. Using the opsonophagocytic assay, antibody activity to several strains of types Ia, II, and III GBS were also demonstrated with IGIV. To ensure that the IGIV activity was in fact antibody, globulin from IGIV was isolated and analyzed. Purified IgG retained opsonic activity in vitro and also provided protection in experimental GBS disease. Variation in the quantity of IgG necessary for protection was observed in different GBS strains. Since IGIV has opsonic and protective activity against several strains and serotypes of GBS, its intravenous administration may provide a valuable adjunct to standard antibiotic therapy for neonatal GBS infections.

Animals↗
PubMed1982

Measuring selection coefficients affecting the alcohol dehydrogenase polymorphism in Drosophila melanogaster.

This paper describes a perturbation experiment on the frequency of the F and S Alcohol dehydrogenase (Adh) alleles of D. melanogaster. Fifty-four iso-female lines set up from three wild populations and with initial F frequencies of either 0.25, 0.50 or 0.75 were maintained on standard laboratory food medium at 22 degrees. At generations 4, 12 and 20 the lines were again scored for Adh gene frequencies. Maximum likelihood procedures were used to estimate selection coefficients for the Adh genotypes. An analysis of deviance was used to compare the coefficients against expectations under the hypotheses of neutrality and of constant values for the three base populations, and for the three initial gene frequency classes. Highly-significant departures from neutrality were observed; over all 54 lines, the set of relative fitnesses for S/S:F/S:F/F was estimated as 1.00:1.08:1.08. In addition, there were significant differences between lines in the outcome of selection which were not attributable to differences between base populations or initial F frequencies. These residual between-line differences, as well as some between-generation, within-line differences are discussed in terms of linkage disequilibria with background genes and electrophoretically cryptic variation at the Adh locus.

Alcohol Oxidoreductases↗
PubMed1982

Modified human immune serum globulin for intravenous administration: in vitro opsonic activity and in vivo protection against group B streptococcal disease in suckling rats.

Human immune serum globulin (ISG) preparations were tested in an in vivo suckling rat protection assay and an in vitro opsonophagocytic assay against various types and strains of Group B streptococci (GBS). Standard ISG provided minimal protection in suckling rats against type III GBS sepsis, whereas preparations of ISG modified for intravenous administration (MISG) provided significant protection against all strains of type III, type II and type Ia GBS tested. Although less protection was obtained against type Ia strains, the survival in suckling rats challenged with all types of GBS varied from 73% to 91% with MISG therapy, as compared with 5% to 12% survival in untreated animals. In this in vivo model, MISG was protective even when administered after bacterial challenge, but had to be administered within 5 h of infection. MISG also had high in vitro opsonic activity against GBS types III and II, but was less effective with some type Ia strains. Just as MISG was more protective than ISG in vivo, it also was more opsonic in vitro. A detailed comparison of one lot of MISG with its parent ISG revealed that the modified preparation actually contained less IgG. When equivalent concentrations of affinity-purified IgG from both preparations were tested, the IgG from MISG was significantly more opsonic. Since the affinity purification procedure eliminated the possibility that IgM or substances introduced in the modification process were actually responsible for the enhanced bactericidal activity, it appears that the individual IgG molecules in MISG may be more effective. These studies suggest that MISG which has been modified by reduction and alkylation for intravenous administration may provide a valuable adjunct to chemotherapy in the treatment of GBS disease in the neonate.

Animal Population Groups↗
PubMed1982

Fatty infiltration of the liver--an imaging challenge.

Ten patients with fatty liver, distinct from the well known diffuse alcoholic variety, comprise this report. All patients had an initial ultrasound examination followed by 99mTc-sulfur colloid liver and computed tomography (CT) body scans. Six patients had focal fatty infiltration producing a space-occupying mass within the liver. Four had ultrasound evidence of diffuse fat occurring in association with focal masses. These masses were all echo poor relative to the adjacent fat, and were subsequently found to represent nodules of normal uninvolved liver in two patients, and metastatic neoplasm and multiple liver cysts in single patients respectively. The clinical picture associated with fatty liver is variable and may include, in addition to alcohol abuse, obesity, malnutrition, exogenous glucocorticoids, diabetes mellitus, and other less well defined factors. Dramatic improvement in fatty liver occurred in two patients following appropriate therapy. The spectrum of changes produced by fatty infiltration of the liver on ultrasonic, radionuclide, and CT scans is extremely varied depending on the amount of fat deposition, its focal or generalized nature, and the presence of associated liver disease.

Adult↗