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Biomedical subjects

G Watt

Publications and source records attributed to G Watt.

At least 73 records · Page 4Linked to original sources
PubMed1994

Immunodiagnosis of trichinellosis: efficacy of somatic antigen in early detection of human trichinellosis.

Crude antigens prepared from the infective stage larvae of Trichinella spiralis were used for antibody detection by indirect ELISA and Western blotting in serum samples taken from trichinellosis patients and from normal, parasite-free controls. The serum specimens were collected from acute ill, symptomatic patients on the first day of treatment (Day 0), and then two months (M2) and 4 months (M4) later. The sensitivities of the indirect ELISA and Western blotting on Day 0 were 81% and 92%, respectively. Both tests were 100% sensitive for M2 and M4 serum samples. Every serum sample from the parasite-free controls tested negative by both immunological assays, indicating 100% specificity. Crude somatic antigens can therefore be used for the early detection of human trichinellosis (acute trichinellosis).

Adolescent↗
PubMed1993

Screen detected high blood pressure under 40: a general practice population followed up for 21 years.

OBJECTIVE: To assess hypertension detected under 40 in a general practice population. DESIGN: Prospective case-control study. SETTING AND SUBJECTS: Former coal mining community in south Wales. Systematic case finding for hypertension and associated risk factors applied to a mean total population of 1945 from age 20 on a five year cycle through 21 years. Mean population aged 20-39, 227 men and 213 women. Case criteria: age < 40 and mean systolic pressure > or = 160 mm Hg or diastolic pressure > or = 100 mm Hg. Age and sex matched controls randomly sampled from the same population. MAIN OUTCOME MEASURES: Mean initial pressures and pressures at follow up in 1989 or preceding death, and all cardiovascular events. RESULTS: 25 men and 16 women met criteria. Estimated five yearly inceptions were 26/1000 for men and 18/1000 for women. Male group mean initial blood pressure was 164/110 mm Hg for cases, falling to 148/89 mm Hg at follow up. Five male cases died at mean age 47.8, compared with two controls at 49.5. Female group mean initial pressure was 172/107 mm Hg for cases, falling to 145/86 mm Hg at follow up. One female case died aged 50, no controls. 10 male cases had non-fatal cardiovascular events at mean age 40.2, compared with two controls at mean age 50.5. Four female cases had non-fatal events at mean age 47.2, compared with one control aged 58. Male differences were statistically significant. CONCLUSIONS: Hypertension under 40 is dangerous, commoner in men than women, rarely secondary to classic causes, and may be controlled in general practice on a whole community basis.

Adult↗
PubMed1993

Amplification of quinine cardiac effects by the resistance-reversing agent prochlorperazine in falciparum malaria.

The use of reversing agents to overcome drug resistance is a potential new treatment strategy for both malaria and cancer. Laboratory studies have raised questions about the safety of this therapeutic approach, but data in humans are lacking. We therefore assessed the toxic potential of reversing agent therapy in Thai patients receiving quinine (17 mg/kg given over 4.5 hr) for falciparum malaria by serial measurements of the QTc interval, an electrocardiographic (ECG) marker of the effect of quinine. Six patients were randomly assigned to receive intravenous quinine alone while another six received one intramuscular injection of 12.5 mg of the reversing agent prochlorperazine (PC; compazine, stemetil) 2.5 hr after the quinine infusion had begun. Compared with baseline values at 2.5 hr, there was prolongation of the QTc interval 30, 60, 90, and 120 min after PC was injected (P < 0.05) but no further lengthening with quinine alone (P > 0.2). Prochlorperazine alone did not lengthen the QTc interval in six healthy volunteers. Neither total nor free quinine plasma levels increased after PC was injected, suggesting that ECG changes may have been due to PC-induced intracellular accumulation of quinine. Although only minor quinine ECG effects were amplified by the reversing agent PC in this study, resistance-reversing therapy could potentiate more serious drug effects. The possibility that more serious toxic effects could be produced by this therapeutic approach should be investigated further.

Electrocardiography↗
PubMed1992

Positron emission tomography imaging-directed stereotactic neurosurgery.

The diagnostic yield of stereotactic biopsies depends upon safely sampling the most representative regions of masses. Potentially, localization information presently available from CT and MR scans might be improved by considering regional levels of cerebral metabolism by PET. In 10 selected stereotactic biopsies of intracranial mass lesions, PET scans were obtained using the Siemens CTI system; the Kelly-Goerss Compass system was used as the stereotactic development platform. PET-[18F]-fluorodeoxyglucose (FDG) images provided clinically significant information by appropriately directing biopsy efforts when CT and MRI was inconclusive or misleading. PET-FDG images can be successfully incorporated into routine image-directed stereotactic surgery.

Astrocytoma↗
PubMed1992

Quinine with tetracycline for the treatment of drug-resistant falciparum malaria in Thailand.

Reports of deteriorating quinine efficacy prompted us to investigate the ability of quinine-tetracycline to clear parasites and fever from patients with multiple drug-resistant Plasmodium falciparum infections. Past and present treatment results were compared at two study sites along the Thai-Cambodian border. In northeastern Thailand, quinine-tetracycline cleared parasites more quickly in 1990 than in 1987 (mean 3.4 and 4.0 days, respectively; P = 0.006). In southeastern Thailand, there were no significant differences between 1990 (n = 26) and 1981-1983 (n = 42) in the time taken to clear either parasites (median 96 and 93 hr, respectively; P = 0.35) or fever (mean 74 and 66 hr, respectively; P = 0.30). In vitro drug sensitivity testing revealed a two-fold decrease in susceptibility to quinine between 1983 and 1990 in isolates from the southeastern Thai-Cambodian border (mean inhibitory concentration 166 ng/ml and 320 ng/ml, respectively; P less than 0.001). We conclude that oral quinine-tetracycline continues to reliably clear parasites and fever from falciparum malaria patients infected in eastern Thailand. Periodic re-evaluations are warranted, however, since the decrease in vitro susceptibility to quinine may be followed by an in vivo decay in the treatment response.

Adult↗
PubMed1991

Ciprofloxacin treatment of drug-resistant falciparum malaria.

A randomized, open study of high-dose ciprofloxacin (750 mg every 12 h) in uncomplicated falciparum malaria was conducted in Thailand. No patient completed the planned 1-week treatment course. Because of rising parasitemia (threefold higher at 36 h than on admission) and deterioration of clinical status, three individuals required quinine treatment 36 h after commencing ciprofloxacin; a fourth was given quinine at 54 h. The study was terminated early for safety reasons after only four ciprofloxacin and four control patients had been enrolled. Ciprofloxacin was well absorbed and efficiently entered erythrocytes; median plasma and red cell concentrations 90 min after the first dose were 4.0 (range, 3.7-6.8) and 5.1 (3.8-6.0) micrograms/ml, respectively. However, 50% inhibition of parasite growth in vitro required 6.6 micrograms/ml, (5.6-9.6). Ciprofloxacin should not be used alone to treat chloroquine-resistant falciparum malaria.

Adult↗
PubMed1991

Hepatic parenchymal dysfunction in Schistosoma japonicum infection.

Decompensated liver disease was investigated in 94 unselected Filipino patients sequentially hospitalized with Schistosoma japonicum infection. Liver damage was objectively scored from 3 (none) to a maximum of 10 (severe damage with encephalopathy) using a modified Pugh-Child grading system. Liver parenchymal dysfunction occurred in 52% of patients and was severe in 21% (hepatic encephalopathy or markedly prolonged prothrombin time). Severity scores were higher in patients with previous gastrointestinal bleeding (7.3 vs. 5.1; P less than .001) and were inversely correlated with admission hematocrit (r = -.60; P less than .001). Ultrastructural analysis revealed abnormalities of Disse's space--the site of blood-hepatocyte exchange. Praziquantel achieved 100% parasitologic cure, but none of the 27 patients followed up for a mean of 9.6 months after receiving it had resolution of liver damage. Liver parenchymal dysfunction is a common problem in hospitalized schistosomiasis patients and persists after parasitologic cure.

Adolescent↗
PubMed1991

Measurement of ciprofloxacin in human plasma, whole blood, and erythrocytes by high-performance liquid chromatography.

A simple, rapid, and accurate high-performance liquid chromatographic method using fluorescence detection is described for the measurement of ciprofloxacin in plasma, whole blood, and erythrocytes. Ciprofloxacin and the internal standard difloxacin were separated on a mu-Bondapak C18 column (30 cm x 3.9 mm inside diameter, 10 microns particle size), using a mobile phase of 0.1 M phosphate buffer (pH 2.5):acetonitrile (75:25, vol/vol). The retention times were 5.1 min for ciprofloxacin and 7.9 min for difloxacin. The compounds were extracted from the three biological fluids using protein precipitation followed by a single-step liquid-liquid extraction. The assay is precise, with interassay coefficients of variation of less than or equal to 9.1% and an accuracy of less than or equal to 7.4% at 0.5 and 5.0 micrograms/ml (n = 5). The mean extraction recoveries of ciprofloxacin in plasma, whole blood, and erythrocytes were 84.4, 63.9, and 48.0%. The limit of detection for ciprofloxacin is 25 ng/ml. Ciprofloxacin concentrations in the three biological fluids were measured in patients with uncomplicated falciparum malaria to demonstrate the application of the method.

Adult↗
PubMed1991

Correlates of blood pressure in 15 year olds in the west of Scotland.

STUDY OBJECTIVE: The aim was to examine social and physical correlates of blood pressure in 15 year olds. DESIGN: This was the first, baseline, sweep of a longitudinal survey of 15 year olds based on a two stage stratified clustered random sample. SETTING: The Central Clydeside Conurbation, in the West of Scotland. In 1981 this had a population of 1.7 million and a standardised mortality ratio (relative to Scotland as a whole) of 109. SUBJECTS: A random sample of households containing 15 year olds were approached by Strathclyde Regional Council; 70% agreed to have their names passed on to the MRC (15% refused, 10% could not be contacted, and 5% had moved). Of these 1177, 11% refused to participate, 3% were not contactable/had moved, and 4% did not provide full data. Complete blood pressure data are available for 959 15 year olds (464 males and 495 females). MEASUREMENTS AND MAIN RESULTS: Blood pressure, pulse rate, height, weight, and room temperature were measured by nurses in the subjects' homes. Smoking, drinking, and frequency of vigorous exercise were self reported. Maternal height, birthweight, occupation of head of household, and housing tenure were reported by parents. After controlling for the other variables, systolic blood pressure was significantly associated with weight, pulse rate, and room temperature in males and with weight, pulse rate, housing tenure, smoking, and exercise in females. Diastolic blood pressure was associated with room temperature in males and with mother's height, pulse rate, and housing tenure in females. Controlling for current weight, birthweight was inversely related to systolic blood pressure in males and positively associated in females, though in neither case were these associations statistically significant. CONCLUSIONS: In males, blood pressure was mainly related to anthropometric factors whereas in females it was additionally related to socioeconomic and behavioural variables. Although not reaching significance, the weight standardised relationship between birthweight and systolic blood pressure was consistent for males, but not females, with those reported by recent British studies of children and adults. The longitudinal design of this study will allow us to examine correlates of blood pressure in the same individuals as they reach social and physical maturity.

Adolescent↗
PubMed1991

Halofantrine for the treatment of mefloquine chemoprophylaxis failures in Plasmodium falciparum infections.

Thai soldiers who became slide-positive for malaria while receiving mefloquine chemoprophylaxis were treated with halofantrine to study its efficacy against mefloquine-resistant falciparum malaria. Thirty-two patients received three doses of 500 mg (1,500 mg total) of halofantrine at six-hr intervals, and were then observed for four weeks. Parasite recrudescence following treatment (median 21 days) occurred in seven of 23 patients (30%) who had mefloquine serum concentrations indicative of regular prophylaxis (greater than 500 ng/ml). Serum concentrations of mefloquine in all 32 patients averaged 950 ng/ml (range 26-2,515) prior to halofantrine treatment. The halofantrine serum concentrations were higher in patients cured by halofantrine than in patients with drug failure, but this was not statistically significant. Patients who were cured by halofantrine had parasites that were more sensitive in in vitro testing to mefloquine (mean [inhibitory concentration] IC50 = 12.5 ng/ml) than in patients whose parasitemias recrudesced (mean IC50 = 23.8 ng/ml) (P less than 0.01, by Wilcoxon rank sum test). These observations suggest that the current formulation and regimen of halofantrine are not optimal for the treatment of multiple drug-resistant falciparum malaria from Thailand.

Animals↗
PubMed1990

Skeletal and cardiac muscle involvement in severe, late leptospirosis.

Information is lacking on the prevalence and severity of cardiac and striated muscle injury in late leptospirosis, and it is unclear whether patients with one type of myositis are at increased risk of developing another. Therefore, 38 patients with severe, late Weil's disease were evaluated for heart and skeletal muscle involvement: 37% had myositis and 39% had abnormal electrocardiograms (ECGs). First-degree atrioventricular heart block and changes suggestive of acute pericarditis were the most common ECG findings. Two patients had transient pericardial friction rubs, but neither pericardial effusion, shock, nor congestive heart failure occurred. Cardiac involvement was not associated with skeletal muscle injury (P = .35), although both manifestations were correlated with severity of disease. Thus, ECG changes and myositis were prominent features of late Weil's disease but cardiac morbidity was not.

Acute Disease↗
PubMed1990

Limulus lysate positivity and Herxheimer-like reactions in leptospirosis: a placebo-controlled study.

Jarisch-Herxheimer reactions are characteristic of some spirochetal diseases and have been reported in leptospirosis, but their pathogenesis and relationship to endotoxin remain unclear. Serial limulus amebocyte lysate assays (LAL) for endotoxin were performed on 40 patients with proven leptospirosis who were monitored for reactions after receiving either intravenous penicillin (24) or saline placebo (16). No Herxheimer-like reactions were observed, although 78% of patients had at least one positive LAL. Serum creatinine, serum bilirubin, and white blood cell counts were significantly higher (P less than .01) in simultaneously drawn LAL-positive specimens than in negative ones. Delayed hepatic clearance of endotoxin due to liver dysfunction may explain the high LAL positivity rate, since assay results correlated with severity of disease but not with the presence or absence of spirochetes. Fear of a Herxheimer-like reaction should not dissuade clinicians from administering antibiotics to patients with leptospirosis.

Adult↗