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Biomedical subjects

W G Smith

Publications and source records attributed to W G Smith.

At least 55 records · Page 3Linked to original sources
PubMed1986

Regulation of in vivo IgE biosynthesis in mice with complete Freund's adjuvant.

Complete Freund's adjuvant (CFA) administered before sensitization dampened the normal and cyclophosphamide-enhanced response of high and moderate IgE responder phenotype mice (CAF1 and C57B1/6J, respectively). CFA-induced suppression of IgE biosynthesis was effective in reducing anaphylactic histamine release from approximately 2,900 ng histamine per milliliter to background levels (less than 100 ng/ml). CFA-induced ascites fluid was able to reduce the cyclophosphamide-enhanced IgE response of low-responder phenotype SJL mice from 1:320 to less than 1:5 as determined by passive cutaneous anaphylaxis. Muramyl dipeptide, a mycobacterial cell wall component capable of eliciting effects similar to those seen with CFA, was shown to induce suppression of IgE production if incorporated in incomplete Freund's adjuvant. Muramyl dipeptide administered in saline was ineffective, while incomplete Freund's adjuvant alone had some immunoregulatory properties. Ongoing IgE responses were less susceptible to regulation. CFA administered to sensitized C57B1/6J mice was ineffective in inducing IgE suppression when animals were challenged with antigen.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1986

Continuous ambulatory peritoneal dialysis: a three year experience.

During a three year period 66 patients with end-stage renal failure were commenced on continuous ambulatory peritoneal dialysis (CAPD) at the Western Infirmary, Glasgow. The patient survival and the technique success rates were 86 per cent and 64 per cent at two years respectively. Biochemical and blood pressure control were very satisfactory on a relatively free diet and usually without the need for antihypertensive drugs. The complications next in frequency to peritonitis were catheter obstruction, postural hypotension and excessive weight gain. The mean hospitalisation period per patient per annum was 33 days, with half of this due to peritonitis. Despite selection criteria favouring older patients, diabetics and those with vascular complications, one third of the patients were able to work.

Adolescent↗
PubMed1986

Peritonitis in continuous ambulatory peritoneal dialysis.

The main complication of continuous ambulatory peritoneal dialysis (CAPD) is peritonitis. This paper describes our experience in the diagnosis and management of this complication in 66 patients during the three years to October 1982. The overall incidence of peritonitis was one episode every 6.75 patient months. Staphylococcus albus and Staphylococcus aureus together accounted for 46 per cent of the episodes, and 24 per cent were culture negative. Catheter exit site infections due to Staphylococcus aureus were common and they may have predisposed to peritonitis with gram -ve organisms as well as to staphylococcal peritonitis. Antimicrobial therapy was effective in 60 per cent of peritonitis episodes. The culture negative episodes usually responded to treatment while those due to fungi, though uncommon, did not. Twenty-nine per cent of these CAPD patients were transferred to haemodialysis because of peritonitis which failed to respond to treatment or which recurred repeatedly.

Adolescent↗
PubMed1985

Increased peritoneal permeability in patients with peritonitis undergoing continuous ambulatory peritoneal dialysis.

The distribution of cefuroxime (250 mg) was studied in patients with renal failure undergoing continuous ambulatory peritoneal dialysis (CAPD). 10 uninfected patients received the drug intravenously and intraperitoneally, while 9 patients with peritonitis were randomly allocated to intravenous or intraperitoneal administration. Samples were taken over the first 6 hour dialysis period. In the infected patients, more drug (p less than 0.01) crossed into the peritoneal cavity following intravenous injection and reached the systemic circulation following intraperitoneal administration than in the uninfected group. This increased permeability of the peritoneal membrane during infection may result in unexpected systemic toxicity in patients treated with intraperitoneal antibiotics.

Adult↗
PubMed1985

Ischaemic optic neuropathy and retinopathy associated with acute pancreatitis.

A man with previously undiagnosed chronic renal failure developed acute pancreatitis. He had severe abdominal pain and simultaneous loss of vision. Ophthalmoscopy showed pale, swollen optic discs, soft exudates and superficial retinal haemorrhages similar to that of Purtscher's retinopathy. We suggest that the ocular changes may be due to fat microemboli secondary to acute pancreatitis.

Acute Disease↗
PubMed1985

Primary medical care and health outcome.

In order to examine the relationship between primary medical care and health outcome, a systemic sample of 485 persons in a typical metropolitan Midwest county was surveyed. Primary care was defined in functional terms including concepts of ready access, continuity over time, comprehensiveness, coordination, and personalized care. Health outcome encompassed self-reported health status, disability, patient satisfaction, and medical costs. Persons who had high levels of primary care tended to have more chronic medical problems and saw physicians more frequently, especially their own principal physician. They clearly were more satisfied with their medical care, but incurred higher medical costs. They did not differ from persons with a low level of primary care in current health status or disability. It was not possible to demonstrate that quality primary care led to better health outcome except on the parameter of patient satisfaction.

Adult↗
PubMed1985

Influence of drug vehicle on ocular contact time of sulfacetamide sodium.

Sulfacetamide sodium drops and ointments were applied to the conjunctiva of patients and volunteers. Tear samples were taken and analyzed for sulfacetamide sodium content. The minimal inhibitory concentrations of the drug in para-aminobenzoic acid-free media were determined to be between 20 and 50 micrograms/mL against Escherichia coli and Staphylococcus aureus, and the effective concentrations of the sulfa were taken as 50 micrograms/mL. The concentration of sulfacetamide sodium in tears fell to the 50 micrograms/mL level in 30 minutes, two hours, and five and a half hours after the single application of 10 microL of 15% and 30% drops and 25 microL of all three ointments, respectively. The ocular contact time of the sulfa was increased by increasing the concentration of drug. The makeup of the three ointments differed greatly, yet the ocular contact time was similar.

Escherichia coli↗
PubMed1984

Inhibition of anaphylactic histamine release and pulmonary distress in rats by nonspecific IgE.

Myeloma IgE, obtained from ascitic fluid of rats previously inoculated with the IgE-producing cell line IR-162, was administered in prophylactic and therapeutic regimens to rats passively and actively sensitized to ovalbumin. Administration of myeloma IgE prior to passive sensitization resulted in approximately 95% inhibition of anaphylactic histamine release and significant protection from anaphylactic pulmonary distress. Myeloma IgE treatment prior and subsequent to active sensitization brought about a 70-80% inhibition of anaphylactic histamine release. A similar pattern of protection was seen in animals that received 5 but not 3 weekly myeloma IgE treatments subsequent to active sensitization. These findings indicate that treatment with nonspecific IgE prior to sensitization is effective in blocking anaphylactic reactions but competition with cell-bound IgE in sensitized animals requires prolonged administration of relatively large quantities of 'nonsense' IgE.

Anaphylaxis↗
PubMed1983

Natural killer cells in in utero diethylstilbesterol-exposed patients.

The observations that limited neonatal diethylstilbesterol (DES) exposure in mice produces persistent natural killing defects and that natural killer (NK) cells have an origin early in gestation suggested the possibility that NK abnormalities may exist in in utero DES-exposed women. However, when compared to controls, these women showed slightly higher NK activity with no evidence of stimulation by accessory mononuclear cells. Altered natural killing cannot be invoked in this population as a contributing factor to increased cancer risk.

Adult↗
PubMed1983

Additional effects of monovalent cations on the lysine-sensitive aspartokinase of E. coli B.

The apparent specificity of activation of lysine-sensitive aspartokinase (E.C.2.7.2.4) from E. coli by monovalent cations differs depending on the assay used and on the Mg2+ concentration. Activity is nearly absolutely dependent on and is highly specific for a monovalent cation in the aspartate semialdehyde dehydrogenase coupled assay or the adenosine triphosphate-adenosine diphosphate exchange assay. Little specificity for monovalent cations is observed using the aspartyl hydroxamate assay. Activation and specificity are also altered by Mg2+ concentrations at a constant 5 mM nucleotide concentration. At a low (1.25 or 1.6 mM)Mg2+ concentration, monovalent cation activation and specificity are nearly absolute. Less dependence on monovalent cations and less specificity are observed at a higher Mg2+ concentration (6 mM). Li+ inhibits aspartokinase competitively with respect to either K+ or NH4+. Monovalent cations are also thermoprotective and differential thermal inactivation experiments at 56 degrees C reveal that NH4+ and K+, either of which will produce maximum catalytic activity, interact differently with aspartokinase. K+ interacts with positive cooperativity, whereas NH4+ does not. K+, NH4+, and Na+ are about equally effective in enhancing the dissociation of the aspartokinase-aspartylphosphate complex. Li+ is less effective.

Animals↗
PubMed1983

Continuous ambulatory peritoneal dialysis and pulmonary function.

Pulmonary function tests were performed in ten patients established on continuous ambulatory peritoneal dialysis. A decrease in all lung volumes was observed after instillation of dialysate and a further decrease on change from the erect to the supine posture. This change was small and unlikely to have a functionally significant effect in patients with a healthy respiratory system. However, in patients with pre-existing lung disease, respiratory function might be further compromised.

Adult↗
PubMed1982

Pregnancy-induced hyporesponsiveness to paternal alloantigens. II. Factors affecting altered expressions of immunity in parous rats.

It was previously demonstrated that female Fischer rats, primiparous by allogeneic DA males, produced only low levels of agglutinating antibody to a challenge skin graft bearing paternal alloantigens, although graft rejection was unimpaired. In this report, the phenomenon of pregnancy-induced hyporesponsiveness was further investigated with regard to factors responsible for its induction and maintenance. Increasing parity by DA males resulted in increased suppression of the Fischer females' agglutinating antibody production postpartum to a challenge skin graft bearing paternal antigens. Moreover, multiparity also resulted in impaired graft rejection, with greater numbers of litters causing more prolonged survival. Either humoral or cellular hyporesponsiveness, or both, persisted for several weeks or even months in many females. Removal of the iliac lymph nodes prior to pregnancy resulted in less severe suppression which was not maintained through the observation period (21 days postgrafting), whereas splenectomy either before mating or on day 7 of pregnancy had no effect. Tubal-ligated females exposed to multiple DA ejaculates, without pregnancy, manifested weakened humoral immunity similar to that of primiparous females, whereas those exposed to (Fischer X DA)F1 hybrid trophoblast multiple times in ectopic sites had not only somewhat suppressed antibody responses but also significantly impaired capacity to reject the challenge allograft. The potential roles of various antigenic stimuli and the complexities of intrauterine antigen processing during gestation are discussed in relation to this naturally induced allosuppression phenomenon.

Animals↗
PubMed1981

Regulatory properties of lysine-sensitive aspartokinase under equilibrium conditions.

The regulatory properties of the lysine-sensitive aspartokinase (ATP : L-aspartate 4-phosphotransferase, EC 2.7.2.4) have been studied under equilibrium conditions by determining the effects of modifiers on the rate of equilibrium isotope exchange between ADP and ATP. The extent of inhibition by lysine, leucine or phenylalanine is almost independent of substrate concentration but is influenced by the substrate/product ratio. Inhibition by a given concentration of inhibitor is increased when the ADP/ATP ratio is increased indicating a regulatory interaction between end products and cellular energy metabolism. Lysine inhibition is cooperative under equilibrium conditions and the parameters of the Hill equation are nearly identical to those obtained in initial velocity studies. A cooperative heterotropic interaction between lysine and leucine is also observed by the ATP-ADP exchange assay just as it is in initial velocity assays. Thus, the regulatory features of aspartokinase that are observed in initial velocity studies are also manifest under equilibrium conditions as revealed by equilibrium isotope exchange rates.

Adenosine Diphosphate↗