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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Mapping human T cell epitopes on phospholipase A2: the major bee-venom allergen.

Phospholipase A2 (PLA2), the major bee-venom allergen, was purified by gel filtration, inactivated by denaturing, and carboxymethylating its cysteine residues. Peripheral blood mononuclear cells from an individual (HLA-DR2 [15], Dw52, DQ1 and DQ3) allergic to bee stings were used to generate cell lines specific for PLA2 and a control antigen, tetanus toxoid. These lines were 90% CD3+, 64% CD4+ and 20% CD8+ by fluorocytometry analysis. T-lymphocyte epitope mapping done with 12 overlapping synthetic peptides of PLA2 revealed two immunodominant epitopes. These epitopes correspond to amino acid sequences 50 to 69 and 83 to 97 of PLA2. Cytokine interleukin-4 and Interferon-gamma secretion was studied from PLA2- and tetanus toxoid-specific cell lines. Interleukin-4 secretion was common to both cell lines but only tetanus-toxoid cell lines secreted interferon-gamma. No interferon-gamma was found to be secreted by PLA2-specific cell line in response to stimulation by PLA2 or the two immunodominant peptides.

Allergens↗
PubMed1992

Preventing violence through primary care intervention.

Homicide was the United States' second leading cause of death among people aged 15 to 24 in 1988; non-fatal assaults occur 100 times more frequently. Yet as a society, we have ignored the problem. Risk factors for violent injuries comprise sociological, developmental/psychological and neurophysiological elements. Providers of primary care for children, young adults and their families can help parents develop healthy parenting techniques in child-rearing, help the grade-school-aged child develop non-violent conflict-resolution skills, and help young people learn to avoid violence and potentially violent activities and situations. Health care providers are able to reduce the incidence of violent injuries by addressing the issue of violence in periodic examination visits with both parents and children. Familiarity with risk indicators enables the health care provider to intervene early when needed. An anticipatory guidance outline and a violence-induced injury-visit form are included.

Adolescent↗
PubMed1992

Sensitivity and specificity of a recombinant transmembrane glycoprotein (rgp21)-spiked western immunoblot for serological confirmation of human T-cell lymphotropic virus type I and type II infections.

Serum specimens (n = 2,712) obtained from individuals residing in diverse geographic regions and categorized as seropositive (n = 122), seroindeterminate (n = 523), or seronegative (n = 2,067) for human T-cell lymphotropic virus (HTLV) infection in accordance with U.S. Public Health Service guidelines were retested by recombinant transmembrane protein (rgp21)-spiked Western immunoblotting. Of the 122 HTLV-positive specimens, those from 85 of 85 (100%) U.S. blood donors, 2 of 2 (100%) Brazilians, 1 of 2 (50%) Indonesians, 14 of 14 (100%) Solomon Islanders, and 18 of 19 (95%) Papua New Guineans reacted with rgp21, yielding an overall sensitivity of 98% (120 of 122). Specimens from individuals whose infections were confirmed to be HTLV type I or HTLV type II by the polymerase chain reaction assay reacted equally well with rgp21. Of the 523 HTLV-indeterminate specimens, those from 21 of 379 (5.5%) U.S. blood donors, 3 of 6 (50%) Brazilians, 10 of 23 (44%) Ugandans, 8 of 49 (16%) Indonesians, 4 of 36 (11%) Solomon Islanders, and 5 of 30 (17%) Papua New Guineans reacted with rgp21. None of these 51 specimens reacted with native gp46 and/or gp61/68 in a radioimmunoprecipitation assay, suggesting a false-positive reaction (9.75%). Of the 2,067 HTLV-negative specimens, 12 reacted with rgp21, yielding a false-positivity rate of 0.6%. These data indicate that while detection of rgp21 is highly sensitive, it can yield false-positive results. Thus, specimens exhibiting reactivity with rgp21 in the absence of reactivity with native gp46 and/or gp61/68 by Western blot should be tested further by a radioimmunoprecipitation assay to verify HTLV type I or type II infection.

Blotting, Western↗
PubMed1992

Malignant melanoma of the parotid gland.

We report a case which demonstrates pitfalls in the management of a parotid gland mass and highlights behaviour of malignant melanoma that is not widely appreciated. The danger of assuming a benign histological diagnosis of such a mass and the subsequent delay of definitive surgery is demonstrated. Metastases within the parotid gland are not uncommon, melanoma being one of the commonest sources. A search should always be made for a primary tumour in the head, neck and chest. This can be made exceptionally difficult by the uncommon phenomenon of spontaneous regression of the primary melanoma.

Humans↗
PubMed1979

Emergency kit.

Explore the source record for details and available documents.

Emergencies↗
PubMed1979

The pancreatic duct mucosal barrier.

The main pancreatic duct in cats possesses a relatively strong barrier to the diffusion of bicarbonate ions (HCO3-). We studied some of the characteristics of this barrier by perfusing the duct with a solution similar in composition to pancreatic juice before and after exposing the duct mucosa to various test agents. The difference in net flux of HCO3- across the duct before and after exposure to the test agent reflected damage to the barrier. The barrier was damaged by infected bile, aspirin (pH 2.3), hydrochloric acid (pH 2.3), ethanol (5 to 10 per cent), and secondary bile acids. It was not damged by sterile bile, aspirin (pH 6.5), and primary bile acids. These data indicate that the barrier to back diffusion in the pancreatic duct has unique properties, different in some respects from the properties of the gastric mucosal barrier. Furthermore, the barrier is vulnerable to some agents thought possibly to have a role in the pathogenesis of pancreatitis and pancreatic cancer.

Animals↗
PubMed1979

Bacteriological monitoring of unheated human milk.

To assess the bacteriological quality of unpooled expressed breast milk, a pilot bottle sample of each donation was examined before the milk was given to the neonate. Provided the milk did not contain greater than 2500 organisms/ml or potential pathogens it was used unheated. Milk containing between 2500 and 5000 organisms/ml and no potential pathogens was used after pasteurisation. Using these criteria, 67% of 460 donations were acceptable. However, because the bacteriological quality varied, 45% of domiciliary donations were discarded compared with only 29% of those from hospital.

Bacteriological Techniques↗
PubMed1979

Grouping of streptococci by Streptex.

Streptex was compared to routine laboratory identification methods available. The results from Streptex sometimes required several attempts before final identification could be achieved. In the main, group D streptococci other than Strep. faecalis failed to group with the Streptex antisera, and this method cannot therefore be used exclusively as a means of identifying this group of streptococci.

Immune Sera↗
PubMed1978

Management of external gastrointestinal fistulas.

We analyzed the course of 186 patients with external gastrointestinal fistulas treated at the University of California Medical Center, San Francisco from 1968 to 1977. There were 82 patients in the earlier group (1968-1971) and 104 patients in the later group (1972-1977). The groups differed in that 35% of patients in the earlier group received TPN, but 71% of patients in the later group received TPN. Of the patients who did not receive TPN, 93% had been adequately nourished using tube feeding methods. The two groups were otherwise similar. The fistula-related mortality (11%) and the spontaneous closure rate of the fistulas (32%) was unchanged over the ten year period. Thus, the principal impact of TPN was to simplify the nutritional management rather than to alter the outcome. When malignancy, previous abdominal irradiation, Crohn's disease, or a short (<2 cm) fistula tract were present, spontaneous closure was less likely than when none of these factors were present (20% versus 47%). Sixty-eight per cent of the deaths occurred in patients with uncontrolled sepsis. Fifty per cent of the deaths were due to the primary disease and were unrelated to the fistula. Spontaneous closure could not be expected to start until sepsis was controlled. Because over 90% of patients whose fistulas closed spontaneously did so within one month after infection was eradicated, we recommend operative closure for most fistulas that persist beyond that time. The most reliable operation is excision of the bowel from which the fistula arises with end-to-end anastomosis. Fistulas not amenable to excision should be managed by bypass.

Adolescent↗
PubMed1977

Influence of probenecid and spironolactone on furosemide kinetics and dynamics in man.

The pharmacokinetics and pharmacodynamics following administration of furosemide (40 mg intravenously) have been studied before and after treatment with probenecid (0.5 gm orally every 6 hr for 3 days) and spironolactone (200-mg initial oral dose followed by 50 mg every 6 hr for 3 days) in 6 normal male subjects. Urine losses during each study period were replaced with saline-dextrose-KCl intravenously. The study was performed with the use of a Latin-square design. Probenecid pretreatment induced significant reductions in renal clearance of furosemide by 78%, the extrarenal clearance by 56%, and the volume of distribution by 52%. As a consequence, furosemide half-life was increased by 54%. Probenecid significantly reduced the rate of sodium excretion at all plasma concentrations of furosemide, but the ratio between urinary furosemide concentration and urinary sodium concentration was not altered. Since the proportion of furosemide excreted unchanged in the urine was not markedly changed, total diuretic response was not influenced by probenecid. There was no evidence of any pharmacokinetic interaction between spironolactone and furosemide. The relationship of furosemide kinetics to dynamics observed in these studies confirms that, in man, the diuretic response is determined by drug that reaches the renal tubule rather than the drug level in plasma.

Adult↗