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Biomedical subjects

E Todd

Publications and source records attributed to E Todd.

At least 19 recordsLinked to original sources

Classification of grossly detectable abnormalities and conditions seen at postmortem in Canadian poultry abattoirs according to a hazard identification decision tree.

This study was designed to review all grossly detectable abnormalities and conditions (GDACs) encountered in poultry in Canadian abattoirs to determine which have potential to cause adverse health effects for the consumer. Review of the literature and consultation with scientists in the field of microbiology, epidemiology, poultry pathology, chemistry, and meat inspection served to generate an inventory of GDACs, and a decision tree containing algorithms was developed to identify GDACs potentially representing a health hazard to consumers. Through the use of the decision tree, GDACs were classified into different categories with regard to the risk they represent to humans. A number of GDACs were identified as being of potential concern from a food safety perspective, namely Erysipelas, fowl cholera, Campylobacteriosis, clostridial diseases, hepatitis/enteritis associated with Helicobacter, Listeriosis, Salmonella infections (nontyphoid infections, Salmonella arizonae, pullorum disease, and fowl typhoid), Staphylococcosis, and Toxoplasmosis. Further characterization--i.e., hazard characterization, exposure assessment, and risk characterization--is required to quantify or better characterize the probability that products derived from affected carcasses may affect the consumer as well as the resulting consequences. Risk assessment is a dynamic process. Results presented in this paper are based on available information and expert opinion. As new information is obtained, the inventory of GDACs and their classification may be modified.

Abattoirs↗

The normal kidney growth rate during year 1 of life is variable and age dependent.

PURPOSE: The concept of normal contralateral kidney growth rate was introduced as a parameter to consider in conjunction with others in the evaluation of unilateral hydronephrosis in asymptomatic neonates and infants. Historically measurements of renal size obtained at different times from different patients have been relied on to construct normal renal growth charts. We report normal kidney growth rates in year 1 of life derived from interval ultrasound measurements of renal size in the same newborns and infants longitudinally with time. MATERIALS AND METHODS: We reviewed 333 normal renal ultrasound studies performed between 1991 and 1995 in 55 patients during year 1 of life. These longitudinal measurements were made bilaterally 2 to 8 times (median 3) per patient. Growth curve models that consider random patient effects were used to estimate the mean growth curve and ascertain its form. We also reviewed an additional 91 ultrasound studies in 10 patients with myelomeningocele without hydronephrosis or reflux. We analyzed the kidney growth rate in a similar manner and compared the results with those in the normal patients. RESULTS: Analysis of the normal cases revealed a changing growth rate during year 1 of life estimated to be 3.1 mm. per month at birth, decreasing gradually during the first 7 months of life to 0.25 mm. per month and remaining constant thereafter (p = 0.0064). Mean kidney size at birth was estimated to be 42.8 mm. (95% confidence limits 27.0 to 58.5). At age 7 months mean size was 60.7 mm. (95% confidence limits 40.1 to 81.3). CONCLUSIONS: These data demonstrate that normal kidney growth is age dependent. A rapid but slowly decreasing growth rate during the first 7 months of life is followed by a more constant and lower rate. The data also suggest that unusually rapid growth, such as that which may occur in the normal contralateral kidney in unilateral obstruction, may also be age dependent, exceeding 5.0 mm. per month during the first 7 months of life and 2.0 mm. per month thereafter.

Age Factors↗

Influence of cocaine, ethanol, or their combination on epicardial coronary arterial dimensions in humans.

BACKGROUND: Cocaine and ethanol are often abused concomitantly, and this combination may be more lethal than either substance alone. Although previous studies showed that cocaine causes coronary arterial vasoconstriction, the combined effect of cocaine and ethanol on the coronary vasculature in humans is unknown. Thus, we assessed the effects of intranasal cocaine, intravenous ethanol, or a cocaine-ethanol combination on heart rate, systemic arterial pressure, and coronary arterial dimensions in humans. METHODS: Thirty-four subjects with chest pain (27 men and seven women, aged 34 to 67 years) who were referred for catheterization received one of the following pharmacologic interventions: (1) intranasal (2 mL) and intravenous (5 mL/kg) saline (n = 8 [group A]); (2) intranasal cocaine (2 mg/kg) and intravenous saline (5 mL/kg) (n = 9 [group B]); (3) intranasal saline (2 mL) and intravenous 10% ethanol (5 mL/kg) (n = 9 [group C]); or (4) intranasal cocaine (2 mg/kg) and intravenous 10% ethanol (5 mL/kg) (n = 8 [group D]). Heart rate, systemic arterial pressure, left coronary arterial dimensions (by computer-assisted quantitative angiography), as well as blood cocaine, ethanol, and cocaine metabolite concentrations were measured before and 30, 60, and 90 minutes after initiation of the intravenous infusions. RESULTS: No hemodynamic or angiographic changes were observed in the group A (saline) subjects. In the group B (cocaine) subjects, the heart rate-systolic arterial pressure product increased by 5% and 10% at 30 and 90 minutes, respectively, and coronary arterial diameter decreased by 14% at these times. In the group C (ethanol) subjects, no hemodynamic changes were noted, but coronary arterial diameters increased by 12%, 11%, and 12% at 30, 60, and 90 minutes, respectively. In the group D (cocaine-ethanol) patients, rate-pressure product increased by 17%, 10%, and 16%, and coronary arterial diameters increased by 7%, 12%, and 13%, at 30, 60, and 90 minutes, respectively. CONCLUSION: The combination of intranasal cocaine and intravenous ethanol causes an increase in the determinants of myocardial oxygen demand. However, it also causes a concomitant increase in epicardial coronary arterial diameter.

Adult↗

Differential adherence of Acanthamoeba to contact lenses: effects of material characteristics.

BACKGROUND: Acanthamoeba-associated keratitis occurs most often in contact lens wearers. The contact lens material may affect its ability to act as a mechanical vector, permitting transfer of viable amoebae from the storage case to the corneal surface. The purpose of this study was to investigate the effects of ionicity and water content on the comparative quantitative adherence of Acanthamoeba trophozoites and cysts to new, unworn hydrogel contact lenses and rigid gas-permeable contact lens materials. METHODS: Sixteen quarter segments of each of 8 types of unworn hydrogel lenses representative of FDA groups 1 to 4 were exposed to freshly prepared cultures of either trophozoites or cysts of A. castellanii or A. polyphaga for 1.5 h, and then washed. Three types of rigid lens button were similarly exposed to A. castellanii trophozoites or cysts. Adherent trophozoites and cysts were then enumerated. RESULTS: All hydrogel lenses showed binding of both trophozoites and cysts, with the former predominating in every case. It was primarily the ionic nature of a lens surface and secondly its water content that was associated with increased quantitative adherence of Acanthamoeba. Neither form of the amoebae bound to any of the hard lens buttons. CONCLUSIONS: Greater relative potential exists for contamination of ionic and high-water content hydrogels by Acanthamoeba. This combination may influence mechanical transmission of the protozoon to the corneal surface. Adherence to hard lenses (as buttons) did not occur if a postincubation wash step was performed.

Acanthamoeba↗

Patient satisfaction with current impotence therapy.

One hundred ninety-eight impotent men were evaluated between July 1993 and June 1994. A "patient goal-directed" approach was used in all cases. Treatment options presented to patients included: oral yohimbine, vacuum constriction devices, penile self-injection therapy, penile prostheses, and testosterone supplementation when clinically indicated. Thirty-two percent of patients declined treatment, and 67% chose nonsurgical therapy. Only two patients (1%) chose penile prostheses. In August 1994, a survey addressing satisfaction with therapy was mailed to all patients, and 99 men (50%) responded. Of the treated respondents, 80% stated that their therapy was "easy to use," and 70% reported that they were "able to have intercourse." Patients prefer nonsurgical impotence therapy, which restores satisfactory sexual function in most men.

Adult↗

Experimental oral toxicity of domoic acid in cynomolgus monkeys (Macaca fascicularis) and rats. Preliminary investigations.

A recent outbreak of marine food poisoning in humans was attributed to the consumption of blue mussels (Mytilus edulis L.) contaminated with domoic acid (DA) that was produced by the diatom Nitzschia pungens. The clinical and morphological effects of single oral doses of extracts of mussels contaminated with DA or of DA isolated from toxic mussels were investigated in small groups (one to six) of cynomolgus monkeys (Macaca fascicularis; 0.5-10 mg DA/kg body weight) and of Sprague-Dawley rats (60 to 80 mg DA/kg body weight). Control animals were either given saline or were not treated. To test whether monosodium glutamate, present in the food consumed by some affected humans, and dimethylsulphoxide, suspected of being present in the plankton, enhanced the response, monosodium glutamate (at 0.25% of mussel extract bolus) or dimethylsulphoxide (at 1 g per bolus) were co-administered to two (one each) of the DA-treated monkeys. DA-treated monkeys developed transient excitation characterized by vomiting. DA-treated rats showed withdrawal followed by hyperexcitation and death (in one case). Mild to moderate central nervous system lesions consistent with neuroexcitation were present in both monkeys and rats. The addition of monosodium glutamate and dimethylsulphoxide had no significant effect on the appearance and severity of central nervous system clinical signs and lesions. The wide variations in the response of test animals to orally administered DA were attributed to the protective effect of vomiting, and to suspected incomplete or slow gastro-intestinal absorption of the toxic agent. The results reinforce the view that DA is an emetic and that under appropriate conditions may also inflict excitotoxic central nervous system damage.

Administration, Oral↗

Increased sensitivity of the rapid hydrophobic grid membrane filter enzyme-labeled antibody procedure for Escherichia coli O157 detection in foods and bovine feces.

Several strains of Escherichia coli O157:H7 artificially inoculated into vegetables and dairy products were recovered on hydrophobic grid membrane filters and enumerated by an enzyme-labeled antibody assay. The mean of the recoveries from 12 fresh vegetables was 108.8%, whereas that from 10 dairy products was 93.2%. Modified tryptic soy broth at 43 degrees C with shaking at 100 rpm provided optimum recovery of the organism from meat, with a sensitivity of less than or equal to 1 CFU/g, which is 10 times more sensitive than direct plating. The method performed equally well with vegetable and dairy products. Tryptic soy broth, however, under the same conditions gave the best results for fecal samples. Of 22 asymptomatic dairy cattle, reported as having positive Brucella titers when assayed with polyclonal antibodies, eight were found to contain E. coli O157 in their feces as demonstrated by the enzyme-labeled antibody assay by using monoclonal antibodies. This finding may explain some of the false-positive Brucella tests.

Animals↗

Steady state verapamil tissue distribution in the dog: differing tissue accumulation.

Plasma, heart, and extracardiac tissue verapamil concentrations were measured after sustained intravenous infusions in 11 dogs to determine the differential tissue accumulation of verapamil. A steady state verapamil concentration of 327 +/- 50 ng/ml decreased the mean arterial blood pressure from 104 +/- 9 to 90 +/- 6 mm Hg (p = 0.08) and the P-R interval increased from 118 +/- 4 to 176 +/- 13 ms (p less than 0.001) with second-degree atrioventricular block developing in 6 animals. Verapamil accumulated in organs in the following order: Lung much greater than kidney greater than spleen greater than ventricular myocardium = liver greater than atrial myocardium greater than cerebral cortex greater than fat = skeletal muscle. Levels in the ventricular free wall were consistently greater than atrial levels, but no difference was observed between left versus right-sided cardiac chambers. In summary, affinity of different organs for verapamil is highly variable and organ-specific; furthermore, differential intracardiac chamber accumulation occurs.

Animals↗

A controlled study of diet in patients with gout.

To determine whether patients with gout have a diet which is distinctive in quality or quantity a careful dietary questionnaire was posed over 7 days to 61 men with gout and 52 control subjects. The average daily intake of most nutrients, including total purine nitrogen, was similar except that the patients with gout drank significantly more alcohol. Beer was the most popular beverage, and 25 (41%) of those with gout consumed more than 60 g alcohol daily (equivalent to 2 . 5 litres of beer). The heavy drinkers had a significantly higher intake of purine nitrogen, half of which was derived from beer. Though the effect of ingested purine on the blood uric acid is difficult to estimate, it probably was sufficient to have a clinical effect, augmenting the hyperuricaemic effect of alcohol itself.

Alcoholic Beverages↗

Expression of terminal deoxynucleotidyl transferase in human thymus during ontogeny and development.

Expression of the enzyme terminal deoxynucleotidyl transferase (TdT) was studied in human thymus during ontogeny and development. In five fetal thymus samples, the enzyme activity was barely detectable. At birth, the terminal transferase activity remained low. Maximum expression of the enzyme activity occurred between 10 and 40 mo of age. Analysis of six other enzyme activities, adenosine kinase, deoxyadenosine kinase, AMP deaminase, dAMP deaminase, 5' nucleotidase, and adenosine deaminase confirmed the normal status of the thymic tissue. A careful analysis of thymic architecture revealed that involution did not occur as a result of the disease process that necessitated cardiac surgery. By immunofluorescence, the TdT antigen was localized exclusively in the nucleus of cortical thymocytes. Protein immunoblotting studies indicated that human thymic terminal transferase exists as a single high m.w. species in individuals under 30 mo of age. Thereafter, a variant m.w. species is detectable. The increase in expression of this enzyme coincides with the increase observed in serum immunoglobulin levels during maturation and precedes the maximum development of the human thymus.

Adolescent↗