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Biomedical subjects

W S Hunter

Publications and source records attributed to W S Hunter.

At least 55 records · Page 3Linked to original sources
PubMed1983

Brain and deep abdominal temperatures during induced fever in pregnant rabbits.

Rectal (Tre), hypothalamic (Thy), and uterine (Tut) temperatures were monitored before and during the course of prostaglandin E1 (PGE1)-induced fever in pregnant rabbits on days 10, 12, 16, 18, 24, 26, 29, and 31 after mating. Tre and Tut were consistently higher than Thy in both nonpregnant and pregnant normothermic does, but changes in the three parameters were closely correlated. In near-term rabbits, both Tre and Thy were significantly lower than in the same does before pregnancy, and the Tre-Thy difference was significantly less than for the same animals before pregnancy, with near-term Thy maintained at a relatively higher level than Tre or Tut. Fever height in the various stages of pregnancy was not different from that observed before mating.

Abdomen↗
PubMed1982

Changes in nasolabial angle related to maxillary incisor retraction.

Changes in the nasolabial angle of the soft-tissue profile were assessed quantitatively in a serial cephalometric study of fifty treated subjects and forty-three untreated subjects, all of whom had Class II, Division 1 malocclusions. Correlations, simple and multiple regression analyses, and multifactorial analysis of variance were used to examine the changes in the nasolabial angle owing to incisor superius retraction and associated skeletal displacements. There were no significant changes in nasolabial angle because of growth. However, the greater the maxillary incisor retraction, the greater was the increase in nasolabial angle. Increase in the nasolabial angle showed a significant correlation with treatment-related increase in the vertical dimension of the lower face. The soft-tissue profile followed closely the underlying skeletal framework. Extraction and nonextraction treatment procedures did not show significant differences in the changes of the nasolabial angle. Results permit prediction of the changes in nasolabial angle owing to incisor superius retraction in orthodontic treatment.

Adolescent↗
PubMed1982

Relationship between lower arch spacing/crowding and facial height and depth.

Previous research into the origins of lower incisor crowding have not yet established the part played by skeletal morphology in its development. Longitudinal cephalometric records of twelve cases with spaced lower teeth were compared with those of twelve moderately crowded cases and twelve severely crowded cases. Significant differences were found between the three groups. These suggested that crowded cases are more likely to have larger Frankfort--mandibular and occlusal plane angles and shorter posterior face height and mandibular body. Both lower incisors and mandibular symphysis were found to be less protrusive in the crowded cases. During the period of study, from 8 years to 14 years, mandibular prognathism increased more in the spaced cases, although labial inclination of lower incisors increased less in these subjects.

Adolescent↗
PubMed1981

Thermal balance in ketamine-anesthetized rhesus monkey Macaca mulatta.

A partitional calorimetry study compared thermoregulatory responses of unanesthetized adult rhesus monkeys (4 female, 1 male) to those anesthetized with ketamine HCl and exposed to ambient temperature (Ta) of 18, 29, 38 degrees C. Steady-state metabolic heat production (M), mean skin temperature (Tsk), rectal temperature (Tre), respiratory evaporative heat loss (Eres), and total evaporative heat loss (Etot) were measured at each Ta. Average Tre of anesthetized animals was reduced by approximately 1 degree C at Ta 18 degrees C, but thermal balance in anesthetized and control animals was maintained by reflexly decreased tissue conductance and shivering. For anesthetized animals, the average M increased 1.8 times over the lowest value of 40.13 W/m2 at Ta 29 degrees C, compared to a 1.5-fold increase for controls. Responses for both groups were not different at Ta 29 degrees C, both groups regulated body temperatures by vasodilation and increased sweating, but with ketamine sweating was reduced (35%). Effective tissue thermal conductance (K) was lowest at Ta 18 (10.8 W/m2 . degrees C) and increased to 39.4 W/m2 . degrees C at Ta 38 degrees C. No significant difference in K was found between ketamine and control groups at other Ta's.

Animals↗
PubMed1981

Review: the Michigan cleft twin study.

The combined effects of clefting of the lip and/or palate and of their surgical repair have been examined for a cross-sectional sample of 20 MZ and 25 DZ like-sexed twins discordant for clefting, in the age range of 4 to 17 years. The findings of four studies published since 1975 on that sample are explored for the primary, contiguous and pleiotropic effects of clefting. The primary effects on facial structures of repaired cleft lip appear to be minimal. However, for twins with repaired cleft of the palate (with or without cleft of the lip), the maxilla was both deficient antero-posteriorly and was positioned more posteriorly than in their non-cleft co-twins. The maxillary first molars were usually slightly less erupted in the cleft twins than in the non-cleft twins. The cleft palate only twins had larger cranial base angles than their non-cleft co-twins. A contiguous effect of the posteriorly positioned maxilla was a mandibular rotation downward and backward in the cleft palate and bilateral cleft lip and palate groups but not in the unilateral cleft lip and palate group. The slightly larger cranial base angles found for cleft palate only, although contiguous in location, are more likely pleiotropic effect. The pleiotropic effects include a deficit in height and weight for cleft subjects which appears only after puberty. Although the teeth of the cleft twins tended to be smaller than those of the non-cleft twins, the amount was not clinically significant.

Adolescent↗
PubMed1980

Thermoregulation in Telazol (CI-744)-anesthetized rhesus monkey (Macaca mulatta).

Seven Telazol (CI-744)-[Telazol is an experimental drug (Parke, Davis) composed of two ingredients in equal amounts by weight: tiletamine HCl, designated chemically as 2-(ethylamino)-2-(2-thienyl)cyclohexanone-HCl, and zolazepam HCl, designated as 4-(o-fluorophenyl)-6,8-dihydro-1,3,8-trimethylpyrazolo-3,4-e 1,4 diazepin-7(IH)-one monohydrochloride] anesthetized rhesus monkeys (Macaca mulatta) were exposed to ambient temperatures (Ta) of 15, 23, 29, 35, and 38 degrees C to evaluate the effect of this dissociative anesthetic agent on thermoregulation. Thermal equilibrium in both anesthetized and control animals at Ta 15 degrees C was through peripheral vasoconstriction and metabolic heat production (M); shivering increased M in the anesthetized group to 1.7 times the resting M of 41.4 W x m-2. Both groups at Ta 38 degrees C regulated body temperature by vasodilation and increased skin evaporative heat loss (Esk) due to sweating. Anesthetized animals increased Esk from 6.4 W x m-2 at Ta 29 degrees C to 32.5 W x m-2 at Ta 38 degrees C. Panting was not observed in either group. Effective tissue thermal conductance was lowest at Ta 15 and 23 degrees C (6.9 and 7.6 W x m2 x degrees C-1, respectively), and increased with Ta's above 23 degrees C (45.0 W x m-2 at Ta 38 degrees C). These results indicate that Telazol-anesthetized monkeys maintain thermal balance at ambient temperatures from 15 to 38 degrees C, and that Telazol induces little or no impairment of thermoregulation in rhesus monkeys.

Anesthesia↗
PubMed1980

Craniofacial morphology in twins discordant for cleft lip and/or palate.

The craniofacial structure in 44 pairs of like-sexed twins discordant for cleft of the lip and/or palate was investigated using lateral cephalometric radiographs. While only a slight rotation of the mandible was evident in the twins having cleft lip, more extensive rotation of the mandible was found in the twins discordant for unilateral cleft lip and palate. Larger, though generally non-significant, changes were recorded for the twins affected with bilateral cleft lip and palate. In the twins discordant for cleft palate only, statistically significant differences were found for maxillary length, mandibular corpus length, cranial base flexure (Ar-S-Na), horizontal and vertical positioning of the posterior maxilla, mandibular plane angle, and gonial angle. Although the effect of sex on the within twin differences was not statistically significant, the effects of age, zygosity, and cleft type were. It is suggested that there is an increasing degree of dysmorphism, with increasing severity of clefting from cleft lip only to bilateral cleft lip palate.

Adolescent↗
PubMed1979

Anaesthetic effects of various ratios of ketamine and xylazine in rhesus monkeys (Macacca mulatta).

Intramuscular injection of selected ratios of ketamine and xylazine provided smooth anaesthetic induction, a wide safety margin, and no significant undersirable side effects. Induction and recovery times, duration of anaesthesia, and thermoregulatory ability can be affected by different combinations of ketamine and xylazine. The addition of xylazine to ketamine increases muscle relaxation, recovery time, and duration of anaesthesia, while generally decreasing induction time and thermoregulatory ability.

Anesthesia↗
PubMed1979

An analysis of corneal transplantation: I--graft clarity.

A retrospective review has been undertaken of the clarity results of 378 keratoplasties performed by 6 Toronto corneal surgeons between January 1970 and December 1974. Lamellar keratoplasties were included in the data related to herpes simplex only. In herpes simplex penetrating grafts gave better vision than lamellar grafts. The following factors were statistically important with respect to graft clarity: age of recipient, type of corneal disease, peroperative corneal vessels, first or subsequent graft, pre- and/or postoperative glaucoma, postoperative anterior synechiae, combined procedure, vitreous loss, previous cataract surgery, and follow-up time. The following factors were statistically unimportant with respect to graft clarity: donor age, time from death to enucleation (median 2.8 hours), time from enucleation to use (median 24 hours), sex of donor and recipient, interrupted or running suture, use of microscope, penetrating or lamellar graft in herpes simplex, postoperative astigmatism, and division of postoperative anterior synechiae. Silk (compared with nylon), larger grafts and combined procedures all increased the incidence of graft rejection. Repeat grafts were associated with more preoperative corneal vascularization.

Adolescent↗
PubMed1979

An analysis of corneal transplantation: II--postoperative astigmatism.

An analysis of 153 penetrating keratoplasties was undertaken. The same surgical technique was used in all cases. Three factors had a statistically significant effect on postoperative astigmatism, as measured by keratometry. (1) Astigmatism decreased with increasing follow-up time (P less than 0.05). (2) Vitreous loss at the time of the keratoplasty increased the amount of postoperative astigmatism (P less than 0.05). (3) Females had more postoperative astigmatism than males (P less than 0.05), but this was probably related to a tendency for females to have a greater incidence of postoperative anterior synechiae (P just greater than 0.05), and the fact that all 6 cases of vitreous loss were in females. There was an almost significant trend toward postoperative anterior synechiae being associated with increased astigmatism (P just greater than 0.05), and there was also a trend toward the division of these synechiae reducing the amount of astigmatism. Fifteen of the 153 penetrating grafts were done in cases of herpes simplex. These were compared with 11 lamellar grafts done for herpes simplex, and there was a statistically insignificant trend toward more postoperative astigmatism in penetrating grafts.

Astigmatism↗
PubMed1979

The physician, the university and the community.

A physician is one who practises the healing art, including medicine and surgery -- is that enough? The university is an institution for the promotion of education in the higher branches of learning -- is that enough? The community, which requires both and supports both, has shown signs of discontent which we must appraise and appreciate. Ophthalmology, which has often led the way in the past in scientific endeavour, now has an opportunity to lead again, into areas of need in the community.

Canada↗
PubMed1978

Application of analysis of crowding and spacing of the teeth.

Spacing or crowding of the teeth is measured and analyzed to assist in decisions regarding the maintenance of teeth in their existing positions or their movement to improved positions. Numerical guides always should incorporate a gray zone in which decisions cannot be made without additional information. In the stage of mixed dentition, estimates of the size of unerupted teeth are more accurate than estimates of future spacing or crowding because the perimeter of the arch does not diminish the same amount in all cases. Instead, it appears to be related to the amount of crowding in the mixed dentition. Determination of the amount of crowding or spacing must always be accompanied by consideration of molar, canine, and incisor relationships. In addition, the effect of the dentition on lip posture should also be evaluated.

Child↗
PubMed1978

Prediction of graft fate from cytopathology of recipient button.

We wished to know whether the fate of human corneal grafts could be predicted from the cytological study of recipient's corneal buttons removed at operation. We counted the number of different inflammatory cells in 168 full-thickness corneal buttons, and related the findings to the operative results retrospectively. If inflammatory cells, particularly polymorphonuclear cells are present in significant numbers in the corneal button the chance of a successful graft is reduced by about 20 per cent (P less than 0.05).

Cornea↗
PubMed1978

Use of the antibody assay in immunized mice for the determination of rabies vaccine potency.

At present, the NIH potency test is the most widely used method for determining the potency of rabies virus vaccines. The drawbacks of this test are well known and include significant test variability as well as the use of an unnatural challenge route. The antibody assay in immunized mice involves the assay of sera from mice immunized with serial dilutions of rabies vaccine. The amount of antibody in the sera is expressed in International Units per ml (IU/ml). Sera from identical dilutions of different vaccines are compared for potency with serum from the same dilution of U.S. Reference Rabies Vaccine. A "unit ratio" is calculated by dividing the serum potency value for the test vaccine by that for the reference vaccine at each dilution tested. This unit ratio may then be compared to the antigenic value generated by the NIH test performed on the same vaccines. In this study, results are reported for both duck embryo and human diploid cell culture vaccines using the Serum Neutralization Test in mice as well as the Rapid Fluorescent Focus Inhibition Test to assay the antisera. Correlations are presented between the unit ratio and antigenic value for all vaccines tested. Also, practical applications and limitations of the test are discussed.

Animals↗
PubMed1977

The timing of height and weight deficits in twins discordant for cleft of the lip and/or palate.

The concept that clefting is associated with diminished height and weight was examined in a cross-sectional sample of 45 pairs of twins discordant for cleft of the lip and/or palate from three to 17 years of age. Contrary to expectation, a remarkable similarity between cleft and non-cleft twins was found from three to 10 years of age. It was only from 10 to 17 years of age that the expected diminution in height and weight was observed. Average heights and weights at two-year intervals were compared with population norms for the age range in question for cleft and non-cleft twins. For both height and weight, the "over 10" decrease below the population norms was attributable to the DZ cleft twins. The MZ cleft twins remained very close to the norms while their non-cleft matched siblings exceeded the norm after 10 years of age. In addition, the decreased weight for cleft twins was seen to occur earlier for girls than for boys, suggesting a relationship with the onset of puberty. This was not seen for height. It is, therefore, proposed that the endocrine controls of maturation at puberty are linked in some fashion to cleft of the lip and/or palate.

Adolescent↗
PubMed1975

Clinicopathologic case reports: Optic nerve head metastasis.

A case of tumor metastasis from carcinoma of the lung directly to the cribriform plate is described. Retina and optic nerve were involved, but there was no evidence of tumor invasion of the choroid. It is postulated that the original tumor embolus lodged in a cribriform branch of the arterial circle of Zinn or in the central retinal vessels.

Carcinoma, Squamous Cell↗