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Biomedical subjects

D Smith

Publications and source records attributed to D Smith.

At least 775 records · Page 43Linked to original sources
PubMed1991

Creation of a feline model of obstructive uropathy.

The aim of this project was to create a reproducible, quantifiable feline model of obstructive uropathy. Seventy-three adult female cats of comparable age were evaluated to obtain the normal control urodynamic data base. Twenty-four cats had a silastic cuff installed around the urethra to induce bladder outlet obstruction, and eight underwent a sham operation. Repeated urodynamic evaluations were performed at predetermined postoperative intervals. The obstructed and normal cats inhibited detrusor contractility by reflex striated urethral sphincter activity. Measurements of voiding pressure to verify the presence, and to assess the degree of induced outlet obstruction, required paralysis of the sphincter by curare. Following cuff implantation, voiding pressure increased from a mean normal of 17.2 cm./H2O to 31.6 to 42.5 cm./H2O in animals designated as moderately obstructed, and to 101.7-125.0 cm./H2O in animals designated as severely obstructed. 84.6% of the high pressure bladders developed vesicoureteral reflux. Analysis of resting, low bladder volume, urethral pressure profile (UPP) data and voiding pressures indicate a compensatory sphincteric response to filling in non-curarized animals, and a lack of that response in curarized animals. It appears that implantation of a silastic cuff to prevent full opening of the urethra during voiding, without actually compressing it, is a reasonable model of obstructive uropathy. The observation that the relationship between striated urethral sphincter activity and inhibition of detrusor contractility is influenced by administration of curare was unexpected, and may have clinical implications.

Animals↗
PubMed1991

Relationship of temperature pattern and serious bacterial infections in infants 4 to 8 weeks old 24 to 48 hours after antibiotic treatment.

STUDY OBJECTIVE: A new management approach to selected febrile infants 4 to 8 weeks old evaluated for possible sepsis is outpatient ceftriaxone therapy, with subsequent re-evaluation 24 to 48 hours after presentation. This study assessed whether the temperature profile of such infants during the 24- to 48-hour period after treatment distinguished those with from those without serious bacterial infections (SBIs). DESIGN: Prospective, descriptive clinical study. PARTICIPANTS: One hundred sixty-one febrile infants 4 to 8 weeks old. SETTING: An urban pediatric emergency department and hospital. MEASUREMENTS AND MAIN RESULTS: All infants underwent a sepsis evaluation (lumbar puncture, CBC/blood culture, and urinalysis/urine culture) and were hospitalized for at least 48 hours. Temperatures were measured on presentation and then every four hours during hospitalization. All infants received parenteral third-generation cephalosporin antibiotic therapy, and none received antipyretic medication unless fever was documented. Fever (rectal temperature of more than 38.0 C) was documented during the 24- to 48-hour period after presentation in 28 infants (17.6%)--one of a total of 18 infants (5.6%) with SBI and 27 of a total of 143 infants (19%) without SBI (alpha, more than .2: power .30). All bacterial isolates in cases of SBI were susceptible to third-generation cephalosporin antibiotics. All repeat blood and urine cultures that were performed in infants with bacteremia or urinary tract infections, respectively, were negative 24 hours after presentation. CONCLUSION: Infants 4 to 8 weeks old who remain febrile during the 24 to 48-hour period after presentation and initiation of parenteral antibiotic therapy are less likely to have SBI. This study did not have sufficient power for this difference to be statistically significant.

Body Temperature↗
PubMed1991

Effect of work load and respirator wear on postural stability, heart rate, and perceived exertion.

The effects on postural stability (sway) were investigated for different work loads under conditions of wearing a full facepiece respirator and not wearing any respiratory protection device. Fifteen subjects accomplished light (40 W), moderate (85 W), and heavy (125 W) work loads under the two conditions. Measurements of postural sway were made immediately after each load by using a multicomponent, strain gage-type force platform. Changes in each subject's movement pattern of the center of pressure were quantitated and compared to their initial baseline sway tests. Each subject's heart rate and perceived exertion were also recorded during each condition. A statistically significant effect (p = 0.007) caused by work load was observed for total length of sway with or without a respirator. An interaction approaching statistical significance (p = 0.056) between work load and respirator use was found. This indicated that sway increased more quickly and in a more consistently linear fashion with increasing work load under the respirator condition (p = 0.02) compared to the nonrespirator condition. The results from the respirator condition showed linear increases in postural sway length across the entire range of work loads, but sway length in the nonrespirator condition showed an increase only at 125-W work loads. The greater increase in sway during the postural balance test could be attributable to the increasing work load-induced proprioceptive fatigue effect on the nervous system's ability to process signals from proprioception systems incongruent with body sway. The heart rate was significantly higher during respirator wear (an increase in heart rate averaging 5.62 beats/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

An outbreak of whooping cough in a highly vaccinated urban community.

In 1950 a whole-cell pertussis vaccine was introduced in Cape Town and was followed by a marked decline in reported whooping cough mortality and morbidity. This resulted in reduced awareness of whooping cough as a clinical problem and, in recent years, no routine diagnostic tests for Bordetella pertussis have been performed. An outbreak of whooping cough occurred in Cape Town between 1 June 1988, and 31 May 1989, with 292 children admitted to hospital for whooping cough during this period (hospital admission rate in children under 5 years of age = 187 per 100,000). In an investigation of 239 children attending four pre-primary schools in the city, the whooping cough attack rate was 33 per cent, while pertussis vaccine coverage was 95 per cent. In the latter part of the outbreak nasopharyngeal swabs and serology were performed in patients presenting to a children's hospital with suspected whooping cough. Bordetella pertussis was isolated from 3 out of 34 (9 per cent) children tested and the first isolate was serotyped as type 1,2,4. Available clinical and laboratory evidence indicated that the organism responsible for the outbreak was Bordetella pertussis. Coverage studies for pertussis vaccine in Cape Town indicated that between 81 and 93 per cent of children were fully immunized by 13 months of age. These findings suggest that, since its introduction, the whole-cell pertussis vaccine produced in South Africa has been highly effective in controlling whooping cough. However, it was not able to prevent a moderate scale outbreak, even in the presence of high vaccination levels.

Child↗
PubMed1991

Both genes for EF-1 alpha in Candida albicans are translated.

In previous work, we showed that Candida albicans has two genes, TEF-1 and TEF-2, which encode identical polypeptides for the highly conserved, essential, protein synthesis factor EF-1 alpha (Breviario et al., 1988). This result prompted questions as to whether C. albicans preferentially uses one of the genes over the other and whether both genes are actually translated into protein. Gene-specific sequence differences in the untranslated portion of each gene made it possible to prepare gene-specific oligonucleotide hybridization probes. Results with the probes showed that the relative steady-state mRNA levels of the two genes were equivalent and that the mRNA for each gene was present in active translation complexes.

Blotting, Northern↗
PubMed1991

Melanoma. Differences observed by general surgeons and dermatologists.

A retrospective review of 182 cutaneous melanomas seen at King's College Hospital from 1970 to 1987 showed that surgeons saw much thicker melanomas (median 3.64 mm) when compared to dermatologists (median 1.14 mm). Surgeons saw a greater proportion of nodular melanomas, less superficial spreading melanomas, were less likely to make the correct clinical diagnosis, and were more likely to perform wide excisions for thin melanomas (less than 2 mm) when compared to dermatologists. General surgeons see a different group of melanoma patients compared to dermatologists and manage them differently from dermatologists working with plastic surgeons. There is a need for a combined approach for the diagnosis and management of cutaneous melanoma between specialists.

Dermatology↗
PubMed1991

The role of hysteroscopy in patients having failed IVF/GIFT transfer cycles.

Fifty patients who had undergone 2 or more failed in vitro fertilization (IVF) embryo transfer (ET) cycles or failed GIFT cycles where fertilization had been demonstrated, underwent hysteroscopy; 28% were found to have intrauterine abnormalities which may have been responsible for the failure of the IVF-ET or GIFT. Patients with an abnormality found at hysteroscopy had undergone a significantly higher mean number of transfer cycles. These results suggest that intrauterine abnormalities may be a cause for failure of IVF-ET or GIFT and therefore hysteroscopy should be part of the infertility work-up of all patients prior to undergoing IVF treatment.

Abortion, Spontaneous↗
PubMed1991

A preliminary investigation of inner city adolescents' perceptions of guns.

Three hundred seventy-seven African-American and 201 white adolescents, primarily of low socioeconomic status, were surveyed on perceptions of guns. Chi-square analyses found significant differences by gender and ethnicity. African-American males were more likely to have a pistol at home (47%); both African-American males and females were more likely to have known someone who took a gun to school (57% and 47%) and to have personally known someone who had been shot (87% and 91%). Differences between African-American and white adolescents and between males and females regarding gun control, gun safety, and consequences of gun use are described.

Adolescent↗
PubMed1991

Evidence for hypomotility in non-ulcer dyspepsia: a prospective multifactorial study.

A prospective multifactorial study of symptoms and disturbance of gastrointestinal function has been undertaken in 50 patients with non-ulcer dyspepsia. Objective tests including solid meal gastric emptying studies, gastric acid secretion, E-HIDA scintiscan for enterogastric bile reflux, and hydrogen breath studies were carried out in all patients and validated against control data. Gastroscopy and biopsy were carried out in non-ulcer dyspepsia patients only. Non-ulcer dyspepsia patients were categorised on the basis of predominant symptoms as: dysmotility-like dyspepsia (n = 22); essential dyspepsia (n = 14), gastro-oesophageal reflux-like dyspepsia (n = 11); and ulcer-like dyspepsia (n = 3). In the total non-ulcer dyspepsia population, solid meal gastric emptying was delayed (T50 mean (SEM) = 102 (6) minutes (patients) v 64 (6) minutes (controls), (p less than 0.01) and high incidences of gastritis (n = 26) and Helicobacter pyloridis infection (n = 18) were found. An inverse correlation was observed between solid meal gastric emptying and fasting peak acid output (r = -0.4; p less than 0.01). Indeed gastric emptying was particularly prolonged in eight patients (T50 mean (SEM) = 139 (15) minutes) with hypochlorhydria. In the non-ulcer dyspepsia population oral to caecal transit time of a solid meal was delayed (mean SEM = 302 (14) minutes (patients) v 244 (12) minutes (controls) (p less than 0.01]. Seven patients had a dual peak of breath hydrogen suggestive of small bowel bacterial overgrowth. No association was observed between symptoms and any of the objective abnormalities. This multifactorial study has shown that hypomotility, including gastroparesis and delayed small bowel transit, is common in non-ulcer dyspepsia and may be related to other disorders of gastrointestinal function. No relation between symptoms and disorders of function, however, has been shown.

Adult↗
PubMed1991

Characterisation of respiratory health and exposures at a sintered permanent magnet manufacturer.

Sintered permanent magnets are made from the powdered metals of cobalt, nickel, aluminium, and various rare earths. During production, exposure to respirable crystalline silica and asbestos may also occur. Reported here is a cross sectional study of 310 current and 52 retired hourly employees who worked 10 or more years making sintered magnets. Each participant had a chest radiograph, spirometry, and completed a respiratory questionnaire. Illness logs were also reviewed to calculate the incidence of recorded respiratory disorders. The prevalences of abnormalities in pulmonary function and respiratory symptoms were not higher than found in an external referent population. Although the prevalence of diffuse parenchymal opacities consistent with pneumoconiosis (four workers) was similar to the referent population, one worker had radiographic findings consistent with silicosis and two workers had profusion scores of 1/2 or above, not seen in the referent group. The incidence of reported respiratory conditions in the log, including asthma, was 10 times that of other manufacturers in the same industrial classification category. Excessive exposures to cobalt, nickel, and respirable silica were shown by environmental measurements.

Adult↗
PubMed1991

Early muscular and metabolic adaptations to prolonged exercise training in humans.

A short-term training program involving 2 h of daily exercise at 59% of peak O2 uptake (VO2max) repeated for 10-12 consecutive days was employed to determine the significance of adaptations in energy metabolic potential on alterations in energy metabolism and substrate utilization in working muscle. The initial VO2max determined before training on the eight male subjects was 53.0 +/- 2.0 (SE) ml.kg-1.min-1. Analysis of samples obtained by needle biopsy from the vastus lateralis muscle before exercise (0 min) and at 15, 60, and 99 min of exercise indicated that on the average training resulted (P less than 0.05) in a 6.5% higher concentration of creatine phosphate, a 9.9% lower concentration of creatine, and a 39% lower concentration of lactate. Training had no effect on ATP concentration. These adaptations were also accompanied by a reduction in the utilization in glycogen such that by the end of exercise glycogen concentration was 47.1% higher in the trained muscle. Analysis of the maximal activities of representative enzymes of different metabolic pathways and segments indicated no change in potential in the citric acid cycle (succinate dehydrogenase, citrate synthase), beta-oxidation (3-hydroxyacyl CoA dehydrogenase), glucose phosphorylation (hexokinase), or potential for glycogenolysis (phosphorylase) and glycolysis (pyruvate kinase, phosphofructokinase, alpha-glycerophosphate dehydrogenase, lactate dehydrogenase). With the exception of increases in the capillary-to-fiber area ratio in type IIa fibers, no change was found in any fiber type (types I, IIa, and IIb) for area, number of capillaries, capillary-to-fiber area ratio, or oxidative potential with training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1991

Relationship of fever magnitude to rate of serious bacterial infections in infants aged 4-8 weeks.

We correlated the height of fever with underlying infectious etiology in 683 consecutive febrile infants aged four to eight weeks who received outpatient evaluation for sepsis during a five-year period. The relative number of infants with fever was inversely proportional to fever height, as 51% had a temperature 38.1-38.9 degrees C, 45% had a temperature 39-39.9 degrees C, and 4% had a temperature greater than or equal to 40 degrees C [hyperpyrexia]. There were 34 cases of serious bacterial infections [SBI], including 16 cases of urinary tract infection, 8 cases of bacteremia, 6 cases of bacterial meningitis, and 4 cases of Salmonella enteritis. The rate of SBI increased in direct proportion to fever height, being 3.2% in those with a temperature 38.1-38.9 degrees C, 5.2% in those with a temperature 39-39.9 degrees C, and 26% in those with a temperature greater than or equal to 40 degrees C. The 6.8% rate of SBI in those with fever greater than or equal to 39 degrees C was significantly greater than the 3.2% rate in those with fever less than 39 degrees C [p less than 0.035]; and the 26% rate of SBI in those with hyperpyrexia was significantly greater than the 4.1% rate in those with fever less than 40 degrees C [p less than 0.000004]. In identifying those with SBI, the presence of hyperpyrexia had a sensitivity of 21%, specificity of 97%, positive-predictive value of 25%, and negative-predictive value of 96%.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1991

The optimal psychiatrist-to-population ratio: a Canadian perspective.

A systematic effort is underway to rationalize the planning of physician supply. This paper summarizes the current methodologies available and focuses on the attempts to determine the optimal psychiatrist-to-population ratio in Canada. The impact of several variables influencing this ratio is discussed. An outline of the correlation between target physician supply and requirements of future trainees is presented. While the relevant methodology is rapidly evolving, an improved process of data collection is urgently required. A number of challenges for our profession lay ahead, such as the need for sensitive and reliable measures of the adequacy of psychiatrist and subspecialist supply and public issues arising from the poor geographic distribution of psychiatric manpower.

Canada↗
PubMed1991

The influence of left ventricular relaxation in determination of the intensity of the aortic component of the second heart sound.

In a study of the aortic component of the second heart sound (A2) intensity, using 10 dogs, miniature cardiac accelerometers were attached to the exposed left ventricle (LV) at the apex, and to the surface of proximal aorta, to obtain LV and aortic surface acceleration. Manometer tipped catheters were used to detect aortic systolic pressure and diastolic pressure and time constant of left ventricular pressure fall "T". Drugs (Nitroprusside, Dobutamine and Methoxamine) altered aortic pressure, LV contraction and LV relaxation. When T was +/- 35% of control, the aortic systolic pressure and diastolic pressure were good predictors of A2 intensity. When LV relaxation was impaired, increasing T greater than 135% of control, the A2 intensity for any given aortic pressure was reduced. When relaxation was hyperactive, decreasing T less than 65% of control, A2 intensity was increased. Aortic pressure/T which assessed both aortic pressure and relaxation ability, is a better determinant of A2 intensity than aortic systolic pressure or aortic diastolic pressure alone.

Animals↗