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Biomedical subjects

B Sutherland

Publications and source records attributed to B Sutherland.

At least 19 recordsLinked to original sources
PubMed1998

The fate of paternal mitochondrial DNA in developing female mussels, Mytilus edulis: implications for the mechanism of doubly uniparental inheritance of mitochondrial DNA.

Species of the marine mussel family Mytilidae have two types of mitochondrial DNA: one that is transmitted from the mother to both female and male offspring (the F type) and one that is transmitted from the father to sons only (the M type). By using pair matings that produce only female offspring or a mixture of female and male offspring and a pair of oligonucleotide primers that amplify part of the COIII gene of the M but not the F mitochondrial genome, we demonstrate that both male and female embryos receive M mtDNA through the sperm and that within 24 hr after fertilization the M mtDNA is eliminated or is drastically reduced in female embryos but maintained in male embryos. These observations are important for understanding the relationship between mtDNA transmission and sex determination in species with doubly uniparental inheritance of mitochondrial DNA.

Age Factors↗
PubMed1995

Eijkman's contribution to the discovery of vitamins.

The work by Christiaan Eijkman in Batavia (now Djakarta, the capital of Indonesia) between 1890 and 1900, for which he received a Nobel Prize, is reviewed. While searching for a microorganism responsible for beriberi, he found that a condition of polyneuritis, with similarities to beriberi, could be produced consistently in chickens by feeding them polished rice, and that addition of the silverskin removed during polishing prevented this. He showed further that the silverskin did not act by physically preventing the entry of microorganisms into the endosperm, nor was its action explained by the protein and salts that it contributed. His tentative hypothesis was that this fraction contributed an antidote to a nerve poison produced by the fermentation of starch in the chickens' crop. However, his successor continued to use Eijkman's animal model and was able to show that silverskin supplied some unknown factor(s) that was required regardless of whether or not the diet contained starch. Fractionation eventually showed thiamin to be the active factor.

History, 19th Century↗
PubMed1995

The effect of surgical wound infection on postoperative hospital stay.

OBJECTIVE: To determine the effect of surgical wound infection on postoperative duration of hospital stay. DESIGN: A case-control study nested within a cohort. SETTING: A tertiary-care hospital. PATIENTS: Selected from a cohort of 4702 inpatients who underwent surgical procedures over a 12-month period. There were 3602 patients, 1100 having been excluded because of lack of infection associated with a particular surgical procedure, because of "lumping" of procedures under a nonhomogeneous heading or because a procedure was unlikely to be the reason for the patient's hospitalization. MAIN OUTCOME MEASURE: Postoperative duration of hospital stay. RESULTS: In the cohort 89 wound infections were identified, 73 of these occurring with procedures selected for study. Five patients were excluded from the study because of data deficiencies, leaving 68 patients who underwent 15 different procedures. These were compared with 136 control patients selected by stratified random sample from a list of patients who underwent the same risk-indexed procedure in the same surgical division. Wound infection patients and controls did not differ in anesthetic risk score or procedure duration. Patients with infection remained in hospital 19.5 days longer than controls (95% confidence interval, range from 11.0 to 27.9 days). Deep-seated infections prolonged the hospital stay more than superficial incisional infections (24.3 versus 13.2 days). CONCLUSIONS: Surgical wound infection markedly prolonged the duration of hospitalization in the University of Alberta Hospitals, longer than that documented in previous studies in other countries. Maximizing opportunities to prevent wound infection would be beneficial to both patients and hospitals.

Case-Control Studies↗
PubMed1994

Methicillin-resistant Staphylococcus aureus in tertiary care institutions on the Canadian prairies 1990-1992.

OBJECTIVE: To review experience with methicillin-resistant Staphylococcus aureus (MRSA) in tertiary acute-care teaching hospitals on the Canadian prairies. DESIGN: Retrospective review for a 36-month period, 1990 through 1992. SETTING: Five tertiary acute-care teaching hospitals in three Canadian prairie provinces. METHODS: MRSA isolates and susceptibility were identified through the clinical microbiology laboratory at each institution. For each patient, data collected included duration of institutional residence prior to isolation, patient ethnic background, age, sex, and antimicrobial susceptibility. Epidemiologic typing of strains used restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis. RESULTS: Two hundred fifty-nine MRSA isolates were identified in 135 patients during the 36 months, with substantial institutional variation in number of isolates. No consistent increase in yearly numbers of isolates was apparent. Patients usually had MRSA identified at admission (62%); only one of five centers had the majority of isolates acquired nosocomially. Patients with MRSA present at admission were more frequently of aboriginal (First Nations) ethnicity (62% compared with 14% of nosocomial; P < 0.001). Pulsed-field gel electrophoresis of 167 isolates from 135 patients revealed 46 different strains with little interprovincial or interinstitutional identity of strains. CONCLUSIONS: MRSA isolated in patients in tertiary care institutions in these three Canadian provinces usually is acquired prior to admission. A disproportionate number of isolates are identified in aboriginal Canadians. Epidemiologic typing was consistent with a polyclonal origin of MRSA in this geographic area.

Adult↗
PubMed1994

Development and evaluation of antithrombogenic centrifugal pump: the Baylor C-Gyro Pump Eccentric Inlet Port Model.

The Baylor C-Gyro Pump Eccentric Inlet Port Models (C1E) have been developed aiming for a long-term centrifugal ventricular assist device (VAD) as well as a cardiopulmonary bypass pump. The eccentric inlet port models are characterized by their unique inlet port and secondary impeller vanes. An inlet female pivot bearing, which was fixed to a supporting bar in the prototype model, is directly embedded into the ceiling of the pump casing. An inlet port is then placed off-center to avoid the bearing area, and it is angled between 0 to 90 degrees from the upright position. In addition, small secondary vanes were incorporated into the impeller bottom to accelerate the washout flow behind the impeller. These features attained design objectives proposed for higher antithrombogenicity: a seal-less pump chamber, no stationary parts in the blood path, and acceleration of the secondary flow behind the impeller. The first in vivo experiment using C1E pumps showed excellent antithrombogenicity for up to 18 days when the experiment ceased due to severe infection in the calf.

Animals↗
PubMed1987

The colonization and life-cycles of Musca lusoria, Musca xanthomelas and Musca nevilli, vectors of Parafilaria bovicola in South Africa.

Thriving, permanent colonies of Musca xanthomelas and later of Musca nevilli were successfully established. However, because of the low reproduction potential of Musca lusoria a small colony only was kept for a limited period until life-cycle studies were completed. Larvae were reared on fresh dung from cattle fed lucerne, while in general adults were fed 0.3% citrated ox-blood, whole milk powder, sugar crystals, fresh dung and water. M. nevilli could be colonized only when ox-liver was substituted for ox-blood. A comparison of the life-cycles of M. lusoria and M. xanthomelas under laboratory conditions at a constant temperature of approximately 27 degrees C, 60% R.H. and 24 h illumination revealed major differences between these 2 vector species. M. lusoria deposits single larvae at intervals of approximately 2 days and a female can produce up to 27 in her life-time. An M. xanthomelas female can lay up to 4 batches of eggs, with as many as 33 eggs per batch, at intervals of approximately 5 days. A single female can produce a maximum of 94 eggs. M. lusoria, however, showed survival advantages over M. xanthomelas in that its larvae reached the pupal stage at least a day sooner and its adults survived more than twice as long. The life-cycles of M. xanthomelas and M. nevilli were similar in the laboratory, except for adult dietary requirements. The mean number of mature oocytes in the ovaries of M. nevilli, however, was only 15.7 compared with 26.1 in M. xanthomelas.

Animals↗
PubMed1981

Selenium balance in young men during selenium depletion and repletion.

Selenium balance was determined in six young men fed for 45 days a formula depletion diet (33 to 36 micrograms Se/day) then fed for 25 days a repletion of diet (depletion diet plus 200 micrograms Se/day as high-Se wheat or wheat plus tuna fish). After 12 days of adaptation, Se balance during depletion was rather constant at -21 micrograms/day and Se losses in urine and feces were 54 micrograms/day. During repletion, Se balance was +64 micrograms/day for the first 12 days and +25 micrograms/day thereafter and the subjects regained all the Se lost during depletion. If the gastrointestinal absorption of the food Se in North Americans and New Zealanders is similar (80%), young North American men need a dietary Se intake of about 70 micrograms/day to replace losses and maintain body stores.

Adult↗
PubMed1981

Attempts to transmit Anaplasma marginale with Hippobosca rufipes and Stomoxys calcitrans.

Three attempts to transmit anaplasmosis with field collections of Hippobosca rufipes were unsuccessful, despite the fact that the flies had been fed initially on splenectomized cattle acutely infected with Anaplasma marginale. However, 1 out of the 3 attempts, made concurrently with the others, to transmit this organism with Stomoxys calcitrans was successful. The prepatent period was 27 days.

Anaplasmosis↗
PubMed1980

Physiological age determination in female Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

The primary sex organs of female Stomoxys calcitrans consist of a single pair of ovaries, each containing 80-100 polytrophic ovarioles. A natural population of these females can be grouped according to age into different reproductive categories. The technique described below defines these categories and enables one to distinguish between newly-emerged, nulliparous and uniparous females and females that have reproduced twice (biparous) or more (pauciparous).

Animals↗
PubMed1980

The temperature preferences of the motile stages of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

When adult Stomoxys calcitrans were exposed to a temperature gradient, 66% of them selected temperatures between 20, 1 and 32, 5 degrees C. The larval stages preferred temperatures between 19, 5 and 33, 2 degrees C. Although the differences in the temperature preferences of the different larval stages were not significant, the fully-fed larvae appear to prefer slightly cooler conditions than the feeding stages. The temperature preferences of both the adults and the larvae are not influenced by the temperatures to which the developmental stages of the experimental flies or their previous generations were exposed.

Age Factors↗
PubMed1979

The effect of temperature on the frons width in males of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

Laboratory experiments established that males of Stomoxys calcitrans, raised at a high temperature (30 degrees C), had frons widths that were very significantly smaller (P=0,01) than those of males raised at a lower temperature (20 degrees C). Thus, although the frons width is apparently controlled genetically, it can also be influenced by temperature. It was also established that temperature acted on the fully-fed 3rd instar larva to affect the adult male frons width.

Animals↗
PubMed1979

Some effects of temperature on the adults, eggs and pupae of Stomoxys calcitrans Linnaeus (Diptera: Muscidae).

Adults could only live and reproduce to their full capacity at temperatures between 20 degrees C and 30 degrees C. At 15 degrees C the females laid no eggs, the adult life span was relatively short and the reproductive capacity of females kept at 35 degrees C was low. The thermal histories of the flies had no apparent effect on their later reactions to temperature in any of the parameters tested. The viability rates of S. calcitrans eggs exposed to temperatures between 10 degrees C and 40 degrees C exceeded 84%, but 45 degrees C was lethal. The optimum temperatures for incubation of the eggs was 30 degrees C. Pupae of S. calcitrans seemed to tolerate temperatures between 20 degrees C and 30 degrees C, but their mortalities increased markedly outside this temperature range. Tests showed that pupal mortalities increased linearly with increasing periods of exposure to a temperature of 15 degrees C.

Animals↗
PubMed1978

Nutritional values of different blood diets expressed as reproductive potentials in adult Stomoxys calcitrans L. (Diptera: Muscidae).

Experiments with Stomoxys calcitrans adults showed that different blood diets markedly affect the lifespan and reproductive potential of this species. When fed on blood from herbivores (cattle, sheep, goat, horse and donkey) the adults lay more eggs than they do when fed on blood from omnivores (pig). Blood from carnivores (dog) is even less suitable than that from omnivores, and no eggs are laid when the flies are fed on chicken blood.

Animals↗
PubMed1978

The suitability of various types of dung and vegetable matter as larval breeding media for Stomoxys calcitrans L. (Diptera: Muscidae).

The dung of 7 species of domestic animals, 4 plant materials, standard larval breeding medium and 3 mixtures of some of these materials were evaluated as breeding media for Stomoxys calcitrans larvae. S. calcitrans could not breed in pure chicken dung or in either of the 2 types of sawdust tested, but Pinus spp. sawdust plus chicken dung proved an excellent breeding medium. Of the other media tested, Pennisetum spp. clippings were the least favourable for the development of S. calcitrans larvae. None of the media had any effect on the sex ratio of the adults that were cultured or on the viability of their eggs.

Animals↗