Biomedical subjects
Publications and source records attributed to J Anderson.
We have studied Miettinen's multivariate confounder score method of controlling confounding in case-control studies both theoretically and by simulation. The main conclusion to be drawn from out results is that the method will in many practical situations seriously exaggerate the statistical significance achieved, and its use is not to be recommended.
Two cases are described who developed epileptic seizures whilst taking maprotiline hydrochloride in therapeutic dosage. In both cases the electroencephalogram was normal and the fits stopped on withdrawal of the drug.
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Pulmonary manifestations in 114 patients with at least two sputum cultures positive for M. intracellularis, no history of any kind of tuberculosis, and not other potential pathogen are described. Even with these stringent diagnostic criteria, seven patients had normal chest radiographs and another seven had reticulonodular-appearing disease without a definite focus of infection. In the other 100 patients, 92% had infiltrates in the apical and/or posterior segments of the upper lobes, and 88% had cavitary disease. The cavities were usually multiple and frequently measured over 4 cm. Scarring and volume loss were common, occurring to some degree in 70% of upper lobe foci. Pleural effusions were uncommon (5%) and usually small. Adenopathy was less common (4%) and usually occurred with upper lobe disease in younger patients. Most patients had some degree of endobronchial spread (81%). The radiographic characteristics of Mycobacterium intracellularis are not believed distinctive enought to differentiate it from Mycobacterium tuberculosis.
Three devices used to humidify the air delivered to hospitalized patients were evaluated for their relative hazard as measured by the concentration of bacterial output delivered with the gas. Two of the devices were evaporative types (commonly called "humidifiers"), moisturizing with water vapor, while the third was a nebulizer, delivering water droplets in aerosol form. Reservoirs were seeded with a tracer organism Pseudomonas cepacia (approximately 10(4)/ml) in distilled water. The output gas (approximately 30 1/min) was sampled through an Andersen six-stage bacterial sampler operated at 28.3 1/min. Excess gas was bled off through a Y-tubing. Results indicate that the nebulizer produces heavily contaminated bacterial aerosols (greater than 1000 P cepacia colonies in the 3-minute sampling period) even after a 20-minute warm-up period that raised the reservoir temperature to greater than 45 degrees C. The two evaporative type devices produced virtually no viable organisms even when sampling was initiated with the reservoir at room temperature.
Case records of all patients 30 years of age and under with a proven pathological diagnosis of colorectal cancer at Howard University Hospital between January 1955 and December 1977 were reviewed. Over this 23-year period, 14 cases were documented. All patients were black. This study reaffirms the poor prognosis which accompanies colorectal carcinoma in the young, particularly in those patients with mucinous carcinoma.
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Rabbits treated with 2-deoxy-D-glucose (2DG) (300 mg/kg) show an increased intake of food and water. Pretreatment with haloperidol (1 mg/kg) abolishes the increase in water intake but does not prevent the increase in food intake.
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Exogenous triiodothyronine (T3) was substituted for levothyroxin or desiccated thyroid in 13 athyrotic patients previously treated for papillary, follicular, or mixed papillary-follicular carcinoma of the thyroid. After 4 weeks T3 therapy was discontinued and serial determinations of plasma thyroid stimulating hormone (TSH) concentrations were made. A roughly exponential rise in TSH values, corresponding to a doubling time of 2 days, was observed until a level of 40 microIU/ml was reached, after which the curve passed through a maximum at 20 days. The mean time required for a level of 50 microIU/ml was 11 days, and this time is suggested for TSH determination before I-131 imaging of patients with thyroid cancer. Plasma TSH values in eight patients following "total" thyroidectomy showed a much slower and more variable rise, with a mean doubling time of 7.6 days. Weekly TSH levels beginning at 15 days will provide a rational basis for I-131 imaging in this group, in whom a longer period of hypothyroidism will be required before imaging and therapy. Adherence to these protocols should minimize the duration of hypothyroidism in patients undergoing I-131 treatment of thyroid carcinoma.
Ten patients with severe myxoedema were treated with regular increments of thyroxine. The urine aldosterone excretion rate and plasma-aldosterone level increased with each increasing dose of thyroxine. Two patients in whom the serum-aldosterone rose to abnormally high levels had cardiac failure which resolved when the thyroxine dose was reduced.
To demonstrate increased technical experience with fetoscopy and fetal blood sampling, two groups of macaques were compared to control animals. Group 2 had a perinatal mortality rate that was not significantly different from that of the control group. A 2.7 mm. Hopkins rod lens endoscope encased in an eccentric cannula, 3.8 mm. outside diameter, was used. When compared to the earlier test group (Group 1), the later test group (Group 2) showed greater adequacy of the fetal blood sample for laboratory analysis (P less than 0.01). Anthropometric and hematologic data collected at term births compared favorably in test and control groups, with the exception of the white blood cell count, which was significantly lower with fetoscopy (P less than 0.01). This is the first report of experimental fetoscopy with the use of a control group to provide precise data to aid in clarification of the ethical issues yet unresolved in this technology.
After an interval of four years the same observers re-examined six rain-forest and six savanna villages, using the same standardized techniques. The results of these surveys have previously been reported by area, i.e. rain-forest and savanna. The present paper analyses the incidence of ocular changes by village. In the rain-forest the concentrations of microfilariae in the skin were similar in the six villages and there was, in general, little difference in the incidence and/or deterioration of ocular lesions between these villages. In the savanna the corresponding quantities were much higher in the three more heavily infected villages compared with the three less heavily infected ones. The implications of these findings for the control of blindness due to onchocerciasis in the savanna are discussed.
Foot-and-mouth disease virus isolates of types O, A and SAT 2, from diseased animals in herds routinely vaccinated twice a year were compared antigenically with the vaccine strains in the complement-fixation, neutralization and radial immunodiffusion tests. It was found that strains which had readily infected vaccinated cattle had R values against the vaccine strain in the complementfixation and radial immunodiffusion tests of 30 or less, while strains causing primary outbreaks with little spread had R values of 30-40. Threefold differences in humoral neutralizing antibody concentration between the field variant and the vaccine strain in sera from vaccinated animals were likely to be significant in terms of protection.
Diethylcarbamazine was given as eye drops in varying concentrations in a half-log dilution series from 1.0 to 0.0001% to patients with ocular onchocerciasis. Migration of microfilariae into the cornea, followed by their straightening and disintegration, was observed with delivery rates as low as 0.1 microgram/hour. Dose-related adverse inflammatory reactions, including the development of globular limbal infiltrates with itching and redness, were seen with delivery rates as low as 0.6 microgram/hour, but substantial inflammatory reactions, including severe vasculitis, were seen only with delivery rates of or above 1.0 microgram/hour. This suggests that it should be possible to achieve beneficial clearing of the microfilarial load, without adverse reactions, by continuous non-pulsed delivery of the drug. Technology exists for such delivery, either directly into the eye or systemically by a transdermal system that could give 3 to 7 days' treatment from each application. The observations reported suggest that after preliminary clearing of the microfilarial load by carefully controlled delivery of DEC it may be possible to maintain therapy by less strictly controlled delivery in DEC-medicated salt, or to use treatment with suramin, without incurring substantial adverse reactions, such as a deterioration in vision in cases in which the optic nerve is already compromised. Continuous non-pulsed DEC delivery systems could have a place in the management of onchocercal sclerosing keratitis. The unique opportunities for using the ocular model to define the requirements for beneficial non-damaging therapy with DEC should be explored in further field trials.
Increasing concentrations of levamisole and of mebendazole were applied to 1 eye in groups of 4 patients with ocular onchocerciasis in northern Cameroon. No effect resulted from up to 3.0% mebendazole suspensions, but 3.0% levamisole solutions rapidly caused entry of microfilariae, straightening out and subsequent opacification of previously curled-up living microfilariae, the rapid formation of typical limbal globular infiltrates, and the subsequent formation of fluffy opacities around the microfilariae. These changes are typical of all other drugs so far studied that have a microfilaricidal action on O. volvulus--diethlycarbamizine citrate (DEC), suramin, and metrifonate. The efficacy of 3.0% levamisole approximated to that of 0.03% DEC. This is in keeping with published observations on the filaricidal activity of these 2 compounds. It is suggested that this system of drug testing should be considered for systematic use in the search for more effective and safer drugs for onchocerciasis.
From the examination of 197 patients who presented with one or more head nodules in the Sudan savanna in Cameroon, and from previous examinations of patients with ocular onchoceriasis, it concluded that in this part of Africa the formation of a head nodule is often preceded by the development of ocular lesions. Head nodulectomy is therefore of limited prophylactic value. Head nodules were removed from 107 of these patients, of whom 17 also received diethyl-carbamazine citrate (DEC), and 20 received both DEC and suramin. Fifteen other patients received DEC as the only treatment, and 4 suramin alone, while 5 received both DEC and suramin. From the follow-up examinations at 9, 12, and 24 months after treatment it was concluded that removal of the head nodule was of some benefit to lesions of the anterior segment, but that the procedure should be combined with efficient micro- and macrofilaricidal therapy in patients at risk of developing ocular pathology, that is, those with 15 or more microfilariae per skin snip near the outer canthus. This index can be measured by paramedical personnel and is therefore of great public health importance in the early detection of "at risk" patients.