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Biomedical subjects

R J Thomas

Publications and source records attributed to R J Thomas.

At least 91 records · Page 5Linked to original sources
PubMed1994

Application of PCR to a clinical and environmental investigation of a case of equine botulism.

PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostridium botulinum type B was shown to be prevalent in soils collected from the area in which the foal was raised. Four methods were used to test for the presence of botulinum neurotoxin-producing organisms in 66 soil samples taken within a 5-km radius: PCR and agarose gel electrophoresis (types A to E), PCR and an enzyme-linked assay (type B), hybridization of crude alkaline cell lysates with a type B-specific probe, and the mouse bioassay (all types). Fewer soil samples were positive for C. botulinum type B by the mouse bioassay (15%) than by any of the DNA-based detection systems. Hybridization of a type B-specific probe to DNA dot blots (26% of the samples were positive) and PCR-enzyme-linked assay (77% of the samples were positive) were used for the rapid analysis of large numbers of samples, with sensitivity limits of 3 x 10(6) and 3,000 cells, respectively. Conventional detection of PCR products by gel electrophoresis was the most sensitive method (300-cell limit), and in the present environmental survey, neurotoxin B genes only were detected in 94% of the samples.

Animals↗
PubMed1993

Lead exposures during shipboard chipping and grinding paint-removal operations.

Shipboard chipping and grinding paint-removal operations were evaluated to determine personnel exposures to airborne lead concentrations. Lead concentrations found in the bulk lead-paint samples ranged from 0.0037 to 11.5% by weight. Of the personnel conducting paint removal operations, 62% were exposed at or above the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit for lead of 50 micrograms/m3. Correlations of airborne lead concentrations and bulk lead-paint contents for chipping and grinding operations were statistically significant. Blood lead (Pb) levels were significantly higher in the follow-up blood tests when compared to the initial blood tests taken prior to paint removal. However, blood Pb levels were well below the OSHA allowable level of 40 micrograms/100 g.

Air Pollutants, Occupational↗
PubMed1992

Return to work after uncomplicated myocardial infarction: a trial of practice guidelines in the community.

OBJECTIVE: To evaluate the effectiveness of practice guidelines for return to work after acute myocardial infarction when disseminated from a university-based setting to a practice-based setting. DESIGN: Randomized clinical trial. PATIENTS: A total of 187 patients with uncomplicated acute myocardial infarction. INTERVENTION: Patients were randomly assigned to the intervention (n = 95) or to usual care (n = 92). The intervention consisted of a treadmill test, a counseling session based on the test results, and a consultation letter from a cardiologist to the primary care physician. Individualized recommendations for the timing of return to work, contained in the consultation letter, were based on the patient's risk for recurrent cardiac events. MEASUREMENTS: Questionnaire, chart review, and a phone interview documented the timing of return to work and the rates of cardiac death, coronary angioplasty, coronary artery surgery, and recurrent myocardial infarction. RESULTS: Median intervals between acute myocardial infarction and return to work were similar in both groups (intervention, 54 days; usual care, 67 days; P greater than 0.2). Among patients without myocardial ischemia, however, the interval was shorter in the intervention group than in the usual care group (38 days compared with 65 days, respectively, P = 0.008). Among patients with myocardial ischemia, intervals were similar in both groups (80 days compared with 76 days, respectively, P greater than 0.2). CONCLUSION: Practice guidelines developed in a university-based setting were not as successful in hastening return to work after uncomplicated acute myocardial infarction when tested in a practice-based setting. Physicians' reluctance to follow guidelines for patients with myocardial ischemia reflected their concern with prognosis even though medical outcome was good.

Adult↗
PubMed1992

Suspected botulism in three intensively managed Australian cattle herds.

Serious outbreaks of a paralytic disease in cattle occurring in the spring and summer of 1988 were investigated on three farms in south eastern Queensland, Australia. On one farm 237 (31 per cent) of 770 cattle died, on the second 109 (40 per cent) of 271 cattle died and on the third 30 (8 per cent) of 380 cows died. Botulism was suspected on the basis of the clinical signs, the lack of significant pathology, a failure to incriminate other agents and a positive feeding trial in one sheep. Laboratory tests for the presence of botulinum toxin failed to confirm this diagnosis, and further feeding trials using ingredients of two rations were also negative.

Animal Feed↗
PubMed1992

The efficacy of an albendazole intraruminal controlled-release device against gastrointestinal parasitism in lambs.

The effectiveness of albendazole in a controlled-release bolus in controlling gastrointestinal nematodes in lambs was assessed during the summer of 1986. Faecal egg counts were almost entirely negative throughout in the treated group and larval challenge remained low at below 2000 larvae kg-1. Untreated control lambs showed a characteristic pattern of auto-infection, culminating in a peak pasture larval count of over 70,000 larvae kg-1 and an outbreak of parasitic gastroenteritis in September associated with a serum pepsinogen concentration of 1.183 IU tyrosine and a mean worm burden of 91,165 nematodes at necropsy, including Ostertagia, Trichostrongylus and Nematodirus species. Subject to the restrictions imposed by the size of the bolus, this was considered to be a highly effective method of seasonal parasite control.

Abomasum↗
PubMed1992

Adult onset Still's disease: clinical experience with 18 patients over 15 years in northern India.

Over a 15 year period 18 patients (eight men, 10 women), 16-50 years old, were diagnosed as having adult onset Still's disease. Fever and arthralgia were always present but prominent lymphadenopathy was uncommon and the serosa were rarely affected. The typical rash of this disease was observed in nine patients. Several complications, including deforming arthritis, amyloidosis, granulomatous hepatitis, uveitis, scleritis, cutaneous vasculitis, and cardiomyopathy, were observed during follow up. Two patients were affected by a nosocomial infection during immunosuppressive treatment for uncontrolled disease. There were no characteristic features at necropsy. Ten patients had a monocyclic course that responded well to aspirin and indomethacin, whereas eight had a polycyclic pattern which invariably required treatment with corticosteroids. Serious complications developed exclusively in the latter group. This group of patients requires early, intensive disease modifying treatment.

Adolescent↗
PubMed1992

HTLV-I among U.S. Marines stationed in a hyperendemic area: evidence for female-to-male sexual transmission.

Among 5,255 active duty United States Marines on permanent tour in Okinawa, Japan, screened for human T-cell leukemia/lymphoma virus type I (HTLV-I) seropositivity, 3 (0.06%) were confirmed by Western blot analysis to have core and envelope reactivity. All three seropositive individuals have a history of prolonged sexual contact with Okinawan women, and two of the three individuals are married to seropositive Okinawan wives. Two gave a prior history of gonorrhea, while all three were negative for syphilis (MHA-TP) and hepatitis B. No other risk factors associated with HTLV-I seropositivity in the United States were identified. A banked sample from one individual, obtained 8 months after initial sexual relations with his HTLV-I-seropositive Okinawan spouse and 20 months before being retested in the survey, showed a pattern suggesting seroconversion. Although based on small numbers, these data suggest that female-to-male transmission of HTLV-I occurs in the absence of other cofactors, e.g., ulcerative genital lesions.

Adult↗
PubMed1991

Anti-tick saliva antibody: a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.

Anti-tick saliva antibody (ATSA) has potential as a biologic marker of exposure to tick bites. In 1989, we conducted a cross-sectional study of 304 outdoor workers in Monmouth County, New Jersey, to evaluate associations between self-reported tick exposure, ATSA status, and Lyme disease antibody status. ATSA levels 1) were correlated with an index of tick exposure on the basis of three self-reported measures of tick exposure and outdoor hours worked per week (p = 0.01); 2) were consistently higher in pet owners compared with persons without pets (p = 0.03); and 3) when examined by duration since last tick bite, peaked at 3-5 weeks after tick bite and then declined (p = 0.06). ATSA levels dichotomized at the 75th percentile (approximately two standard deviations above the mean ATSA optical density of 25 subjects who denied recent tick exposure) were associated with self-reported tick exposure: adjusted odds ratios for high ATSA levels were 4.2 (95% confidence interval (CI) 0.9-18.9) for moderate (versus none) tick exposure and 5.8 (95% CI 1.2-27.2) for high (versus none) tick exposure. Finally, high ATSA levels were associated with Lyme disease seropositivity, with an adjusted odds ratio of 3.2 (95% CI 1.3-7.6). The data suggest that ATSA is a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.

Adolescent↗
PubMed1991

Olfactory sensations produced by high-energy photon irradiation of the olfactory receptor mucosa in humans.

During irradiation of volumes that incorporate the olfactory system, a proportion of patients have complained of a pungent smell. A retrospective study was carried out to determine the prevalence of this side-effect. A questionnaire was sent to 40 patients whose treatment volumes included the olfactory region and also to a control group treated away from this region. The irradiated tumor volumes included the frontal lobe, whole brain, nasopharynx, pituitary fossa, and maxillary antrum. Of the 25 patients who replied, 60% experienced odorous symptoms during irradiation. They described the odor as unpleasant and consistent with ozone. Stimulation of olfactory receptors is considered to be caused by the radiochemical formation of ozone and free radicals in the mucus overlying the olfactory mucosa.

Adenoma↗
PubMed1991

Detection of Clostridium botulinum types C and D toxin by ELISA.

An ELISA to detect Clostridium botulinum type D toxin was developed using polyclonal antibodies to a semi-purified toxic complex of the neurotoxin. Sensitivity of the ELISA for detecting type C and type D toxin compared with mouse inoculation was 70% and specificity 96% on samples from animals with botulism diagnosed on clinical signs and herd history. However, both mouse inoculation and the ELISA failed to detect toxin in many animals with a presumptive diagnosis of botulism. Some cross-reaction was seen with Clostridium novyi type A, but not with other clostridial species. While the ELISA described here cannot replace mouse inoculation for the diagnosis of botulism, it is a useful additional test.

Animals↗
PubMed1991

Clinical profile in Barrett's esophagus: who should be screened for cancer?

A retrospective survey identified 96 patients (58 males) with Barrett's esophagus, diagnosed at the Royal Melbourne Hospital between 1978 and 1986. The age at presentation varied from 20 to 93 years, and 43% were greater than 70 years. Heartburn was a presenting symptom in 71%, regurgitation into the pharynx in 54%, dysphagia in 31% and hematemesis or melena in 29%. At endoscopy, the length of Barrett's epithelium ranged from 3 cm to 15 cm. Macroscopic esophagitis was observed in 69%, benign esophageal strictures in 14% and a co-existent adenocarcinoma of the lower esophagus in 10% of patients. Only 30% of the patients were cigarette smokers at the time of diagnosis, but 64% drank alcohol (9% greater than 80 g alcohol daily). Patients with esophageal cancer at presentation were more likely to be male and cigarette smokers (Fisher's exact probability test). It has been suggested that patients with Barrett's esophagus should be screened to detect the early development of esophageal cancer. If patients who already have cancer, the elderly (age greater than 70 years) and those with a chronic alcohol problem (greater than 80 g intake daily) are excluded from endoscopic cancer surveillance, only 42% of the patients described in this survey would be eligible for enrollment in such a program. This represents a recruitment of only 5 new patients yearly in a large teaching hospital endoscopy unit.

Adenocarcinoma↗
PubMed1990

Appetite, digestive efficiency, feed utilization and carcass evaluation of housed calves naturally infected with gastrointestinal nematodes.

The progress of two groups of 10 calves, which had previously been exposed to trichostrongyle infections by grazing infected pastures, was monitored from housing in October to slaughter the following April. Each of the animals of one group had received a morantel sustained release bolus, the other control group remained untreated. The high faecal egg counts and serum pepsinogen concentrations, together with the clinical signs of ostertagiosis observed in the controls in October, persisted during the first month of housing but improved thereafter. From late November onwards, no difference in feed intake and digestive efficiency was observed between the groups. The control calves exhibited a significantly greater feed conversion efficiency over the period February-April, (7.5 vs. 12.3 kg feed kg-1 liveweight gain, P less than 0.001). This reduced the liveweight advantage of the MSRB group over the controls at housing to 25 kg.

Animal Feed↗
PubMed1989

A new gastric carcinoma cell line (LIM1839) derived from a young Caucasian male.

We describe a new and unique gastric carcinoma cell line (LIM1839) derived from a young Caucasian male with rapidly progressing disease. The cell line grows with a pleomorphic morphology and has been in continuous culture for more than 3 years. The cells cannot be cloned in semi-solid agar or grown in nude mice despite numerous attempts. The karyotype of the cultured cells is highly abnormal with a large number of structural and numerical changes. Some chromosomes are dicentric and this feature has persisted in this culture. The cells express one of the small-intestinal dipeptidases, aminopeptidase N, but do not express dipeptidyl peptidase IV or the disaccharidases, sucrase isomaltase or maltase glucoamylase. The cells express high levels of EGF receptors and of messenger RNA for insulin-like growth factor II.

Adenocarcinoma↗
PubMed1989

High-dose chemotherapy with busulphan and cyclophosphamide and bone-marrow transplantation for drug-sensitive malignancies in adults: a preliminary report.

The technique of high-dose chemotherapy and bone-marrow transplantation takes advantage of any potential dose-response effect in the treatment of cancer and the ability of infused marrow to circumvent severe myelotoxicity. We report our initial experience of 20 high-dose chemotherapy procedures with busulphan and cyclophosphamide as the treatment regimen. Autologous (14 patients), human leukocyte antigen-matched, sibling-allogeneic (five patients) and identical-twin (one patient) transplantations were performed in patients with leukaemias (12 patients), lymphomas (seven patients) or a germ-cell tumour (one patient). One in-hospital and one late death occurred as a result of the toxicity of high-dose chemotherapy. All evaluable patients demonstrated bone-marrow engraftment and became independent of blood transfusions. Five of six patients who were treated in partial remission or relapse obtained a complete remission. Seven patients have relapsed. Eleven patients currently are alive and disease-free and nine patients have returned to their full-time occupations. High-dose chemotherapy can be undertaken with an over-all morbidity that is similar to that which is experienced during the induction chemotherapy of acute leukaemia.

Adolescent↗
PubMed1989

An outbreak of ehrlichiosis in members of an Army Reserve unit exposed to ticks.

An outbreak of unexplained illness occurred in members of an army reserve unit after field training in an area of New Jersey endemic for Lyme disease. Nine (12%) of the 74 who attended the exercise had serological evidence of Ehrlichia infection, defined as a single rise in titer of antibody to Ehrlichia canis greater than or equal to 1:160 four weeks after training. Two reservists with early serum samples had documented seroconversion, defined by a four-fold or greater increase in titer of antibody to E. canis, with a peak titer of greater than or equal to 1:160. Reservists with serological evidence of Ehrlichia infection were more than three times as likely to report arthralgia, myalgia, headache, appetite loss, nausea, eye pain, and abdominal pain than the other reservists. No reservist with serological evidence of Ehrlichia infection was hospitalized and most had minimal or no symptoms. This outbreak of ehrlichiosis suggests that the usual symptoms of Ehrlichia infection are milder than previously reported and that ehrlichiosis must be considered in symptomatic persons with recent tick exposure.

Animals↗