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Biomedical subjects

D Fraser

Publications and source records attributed to D Fraser.

At least 145 records · Page 8Linked to original sources
PubMed1989

Nutritive and nonnutritive sucking and the temporal organization of the suckling behavior of domestic piglets.

Detailed video recordings of the suckling behavior of one piglet from each of four litters were analyzed to determine how the components of piglet suckling behavior are organized in relation to the time of milk ejection and the temporal pattern of grunting by the sow. Early in the suckling episode, most piglets massaged the udder with their snouts, and then changed gradually to sucking the teats with slow mouth movements (1-2/sec). The piglets then had a distinct phase of sucking with rapid mouth movements (4-5/sec) which began suddenly and lasted about 5 to 15 sec. The weight gains of piglets removed at different times showed that piglets consumed milk during the fast sucking but not during the preceding slow sucking, regardless of how much slow sucking had occurred. Three of the four sows showed a characteristic increase in rate of grunting about 20 to 25 sec before fast sucking began. The piglets' change from massaging to slow sucking often coincided with the increase in grunt rate, but the timing of the transition varied greatly. This suggests that the change in grunting is one but not the only cue used by the piglets to time their suckling behavior. During the slow, nonnutritive sucking, mouth movements were highly variable in duration, with occasional short bursts of rapid mouth movements. This contrasted with the more uniform duration of fast sucking movements. Evidently, in piglets, nutritive and nonnutritive sucking differ in both rate and temporal patterning.

Animals↗
PubMed1989

Liver histology abnormalities in the morbidly obese.

A prospective study was undertaken in order to investigate the association between clinical and biochemical parameters and the histopathological findings in liver biopsies in the morbidly obese. Wedge liver biopsy specimens were taken at the beginning of the surgical procedure from 100 consecutive morbidly obese patients undergoing Roux-en-Y gastric bypass. Histological abnormalities were found in almost all of the examined material (98 of 100), which ranged from mild fatty infiltration through inflammatory change and alcoholic hepatitis-like change to fibrosis and cirrhosis. The patients with abnormalities were divided into two groups: those with a single abnormality (n = 56) and those with two or more histopathological findings (n = 42). Age, excess body weight, total cholesterol and triglyceride levels were significantly higher in the group with more than one histopathological finding. In a discriminant function analysis, it was found that the preoperatively available measures of age, sex and excess body weight, as well as ALT and triglyceride levels, could discriminate between the two patient groups. A model which uses these variables has been described which correctly assigns the patients to their histology groups in 73% of the cases. This model could provide a useful noninvasive clinical tool for the preoperative evaluation of possible hepatic damage in morbidly obese patients in whom there is no other known cause of possible liver disease.

Adult↗
PubMed1989

Twinning in southern Israel; secular trends, ethnic variation and effects of maternal age and parity.

Twin births in southern Israel between 1970 and 1986 were examined in the Jewish and Bedouin populations. An increase in dizygotic twinning in the whole population, largely due to an increase of rate in the Bedouin population was found. The dizygotic twinning rate in the Bedouin population rose until it reached the level found in the Jewish population. No change with time was found in the monozygotic twinning rates in either population. This suggests that while dizygotic twinning rates are influenced by environmental factors, the monozygotic twinning rates are not. The effects of maternal age and parity on dizygotic and monozygotic twinning rates differed in the two ethnic groups examined. In the Jewish population the dizygotic twinning rate was related to maternal age and parity, while in the Bedouins only maternal age affects the rate. The monozygotic twinning rate has an inverted U shape with maternal age in the Jewish population and is linearly related to maternal age in Bedouin women. No effect of parity on the Jewish monozygotic twinning rate is found but this rate is directly affected by parity in Bedouin women. The effects of maternal age and parity together were examined in both populations. Both maternal age and parity affected the twinning rates; however, the effects are not additive and no interaction between maternal age and parity was found.

Adult↗
PubMed1989

Are fixed-dose oestrogen/progestogen combinations ideal for all HRT users?

Although progestogens protect the endometrium against excessive oestrogen-induced stimulation, they can cause adverse symptomatic and psychological effects and may have undesirable metabolic consequences. Thus, the minimum progestogen dose which results in consistent endometrial transformation should be prescribed. To define this dose for norethisterone and dl-norgestrel, 197 endometrial samples obtained from postmenopausal women receiving conjugated equine oestrogens (0.625 mg or 1.25 mg daily) with one of six doses of norethisterone (or the acetate), or one of three doses of dl-norgestrel added for the first 12 days of each calendar month were examined with the light microscope; 109 samples were also assessed by transmission electron microscopy. There was an inverse relation between the percentage of samples showing proliferative features and the progestogen dose. However, proliferative endometrium was observed in 6% of samples with the highest dose of dl-norgestrel (500 micrograms) and in 3% of samples with 2.5 mg norethisterone. Conversely, complete secretory transformation was observed in 25% of samples with the lowest dose of norethisterone (0.1 mg) and in 40% of samples with 75 micrograms dl-norgestrel. Mild atypical hyperplasia was diagnosed in four samples. There was a wide inter-patient variation in response and none of the nine progestogen dose regimens induced secretory change in every patient.

Cell Division↗
PubMed1989

Ultraviolet irradiation for hepatic rickets.

An infant with chronic cytomegalovirus hepatitis and a child with atypical Alagille's syndrome had vitamin D deficiency rickets due to malabsorption. Both received ultraviolet irradiation. This treatment corrected biochemical abnormalities and healed the rickets. In the infant use of a sunlamp at home maintained normal 25 hydroxy-vitamin D for over a year. Our study shows that ultraviolet irradiation is an effective treatment of hepatobiliary rickets.

Child↗
PubMed1989

Inflammatory bowel disease in migrant and native Jewish populations of southern Israel.

Ulcerative colitis and Crohn's disease were studied in three Jewish populations in the Beer Sheva district of southern Israel. Age-adjusted prevalence rates on 31 December 1987 were for ulcerative colitis, 89/10(5), and for Crohn's disease, 30/10(5). Both diseases were commoner in females and in European-American-born Jews. Age-adjusted incidence rates have increased and in 1979-1987 were for ulcerative colitis, 5.4/10(5)/year, and for Crohn's disease, 2.1/10(5)/year. Females developed ulcerative colitis at a younger age and Crohn's disease at a later age than males. Israel-born patients developed both diseases at a young age. The clinical features of ulcerative colitis were similar in the various populations. Epidemiologic data in Jews may aid in the understanding of the pathogenesis of inflammatory bowel diseases.

Adult↗
PubMed1989

Limited value of leukocyte adherence inhibition in screening for colorectal neoplasia in high-risk groups.

A study of 191 screenees at high risk for colorectal neoplasm was undertaken to evaluate the value of the leukocyte adherence inhibition (LAI) test in detecting colorectal neoplasms. All screenees underwent total colonoscopy and LAI test. Results show that 94/191 (49.2%) screenees had neoplasms. Overall LAI positivity was 18.3% (35/191), which was highly significant, versus an asymptomatic comparison group (7.5%, 11/146). LAI test sensitivity, specificity, and positive and negative predictive values were, respectively, 19.8, 82.7, 45.7, and 58.5%. In this study the LAI test was not found to be a sensitive screening test for colorectal neoplasms. However, as the LAI test result was a significant finding within the study group, it may possibly be a risk factor and identify a subgroup that will require careful prospective evaluation.

Adult↗
PubMed1989

Follow-up of isolated mitral valve prosthesis, 1964-86.

We review the data of 141 patients who underwent mitral valve replacement between 1964 and 1986. In the majority of patients, a tilting disk or a Cage ball prosthesis was implanted. Overall operative mortality was 14.8%, and 120 patients who were followed for a mean period of 4.5 +/- 2 years (540 patient years) showed a late mortality (greater than 30 days postoperatively) of 20.8%. The actuarial survival was 84% at 5 years and 44% at 20 years. Most of the late deaths were cardiac related, with sudden death as the leading cause. The incidence of prosthetic valve-related complications--thromboembolism, bacterial endocarditis and warfarin-related hemorrhage--were higher than in other series; however, long-term survival was comparable. Delay in advising mitral valve surgery is the probable cause of some of the results observed in this series.

Adolescent↗
PubMed1989

Follow-up of isolated aortic valve prosthesis, 1964-86.

Between May 1964 and November 1986, 70 patients underwent aortic valve replacement with (20%) or without (80%) additional surgical procedures. Most of the prosthetic devices were Starr-Edwards models and Björk-Shiley and Sorin tilting disks. Long-term follow-up (305 patient years) was assessed in 65 patients who survived the operation. Actuarial survival was 85 +/- 2% at 5 years and 72 +/- 6% at 20 years. The linearized rate of deaths occurring greater than 30 days postoperatively was 3.6% per patient year; sudden death was the most frequent cause of death. Preoperative functional capacity class significantly influenced the immediate outcome of surgery. Although the incidence of prosthetic valve-related complications was higher than in previous studies, survival rates were comparable.

Adolescent↗
PubMed1988

Neonatal screening and an intensive management programme for galactosaemia: early evidence of benefits.

A prospective study of children with galactosaemia is being undertaken at the Metabolic Clinic, Royal Children's Hospital, Brisbane. The purpose of the study is to collect biochemical, clinical, dietary, developmental and speech and language data. This paper describes the operation of the multiprofessional management programme and reports results for two groups of children: those who were diagnosed before the introduction of neonatal screening in 1982 (the prescreening group) and those who were identified by screening. The eight children in the prescreening group have shown intellectual development in the low-average to moderately-handicapped range. Most of them have speech and language difficulties. The screening group, all of whom are still in infancy or early childhood, appears to be developing normally, with the exception of one child who is showing problems with speech and language. The early results provide a basis for cautious optimism that neonatal screening and careful management will result in improved outcomes for children with galactosaemia.

Galactosemias↗
PubMed1988

Differential behaviour of 25-hydroxyvitamin D3 24-hydroxylase and 1-hydroxylase in response to protein synthesis inhibitors and cytochrome P-450 inhibitors.

To characterize 25-hydroxyvitamin D3 24-hydroxylase and 25-hydroxyvitamin D3 1-hydroxylase, the activities of the two enzymes were measured in the presence of two types of inhibitors. The effect of protein synthesis inhibitors on 25-hydroxyvitamin D3-stimulated 24-hydroxylase activity in 1-hydroxylating rat kidneys perfused in vitro was tested. Actinomycin D (4 microM) and cycloheximide (10 microM) each abolished 25-hydroxyvitamin D3 24-hydroxylase synthesis when added at the start of perfusion but not when added 4 h later; they did not affect 25-hydroxyvitamin D3 1-hydroxylase activity. The effects of cytochrome P-450 inhibitors on the two enzyme activities were then studied in vivo. Metyrapone and SKF-525A (50 mg/kg body weight) each inhibited 25-hydroxyvitamin D3 24-hydroxylase at 6 and 24 h; in contrast 1-hydroxylase increased and was 5 times the control value at 24 h. Finally, the in vitro effects of six cytochrome P-450 inhibitors at concentrations ranging from 10(-7) to 10(-3) M on enzyme activities in renal mitochondrial preparations were compared. Both enzymes were inhibited by all of the inhibitors, but inhibition of 25-hydroxyvitamin D3 24-hydroxylase was consistently greater than that of 25-hydroxyvitamin D3 1-hydroxylase. These studies demonstrate that 24-hydroxylation and 1-hydroxylation respond differently to protein synthesis inhibitors and to cytochrome P-450 inhibitors. The findings are consistent with the hypothesis that the two enzyme activities are associated with different cytochrome P-450 moieties.

Animals↗
PubMed1988

Effects of acute carbon tetrachloride poisoning on vitamin D3 metabolism in the rat.

To achieve biologic potency, vitamin D must undergo two successive hydroxylations, first, in the liver and then, in the kidney. Carbon tetrachloride is known to cause extensive damage to the liver, but its effect on vitamin D metabolism has not been studied thoroughly. The effect of carbon tetrachloride on renal hydroxylation of 25-hydroxyvitamin D3 has not been studied. To evaluate the acute effect of carbon tetrachloride on vitamin D metabolism in the liver, vitamin D depleted rats received a single intraperitoneal injection of carbon tetrachloride (2.0 mL/kg body weight). After 24 h, they were given 55, 550, or 5050 pmol [3H]vitamin D3 intravenously. Twenty-four hours after injection of [3H]vitamin D3, aliquots of serum and liver were analyzed for [3H]vitamin D3 and its metabolites by high performance liquid chromatography. Sera of carbon tetrachloride treated rats had higher [3H]vitamin D3 and [3H]25-hydroxyvitamin D and lower [3H]1,25-dihydroxyvitamin D3 concentrations than did control sera. Livers of carbon tetrachloride treated rats contained more [3H]vitamin D3, [3H]25-hydroxyvitamin D3, and more fat. Liver histology showed massive centrilobular necrosis in the treated rats. Thus, our experiment in rats given an acute dose of carbon tetrachloride provided no evidence of impairment of vitamin D metabolism by the liver, but offered a suggestion that 25-hydroxyvitamin D3 metabolism by the kidney might be impaired. To determine the acute effect of carbon tetrachloride on metabolism of vitamin D3 by the kidney, we studied hydroxylation of [3H]25-hydroxyvitamin D3 in isolated perfused kidney. Kidneys from the treated rats showed a 66% reduction in [3H]1,25-dihydroxyvitamin D3 production.

Animals↗
PubMed1988

Acute acalculous cholecystitis--experimental and clinical observations.

Induction of acute acalculous cholecystitis was studied in dogs. Designed models included ligation of the cystic artery and/or duct separately or combined and injection of colonic flora into the gallbladder. Cholecystectomy was performed 72 h later. Histological studies of the gallbladders and bile cultures demonstrated various degrees of cholecystitis, the severest form occurring as a result of cystic artery ligation, whereas the mildest was produced by injection of bacteria. Secondary infection was a constant feature of our experimental models.

Acute Disease↗
PubMed1987

Keratitis associated with the multiple endocrine deficiency, autoimmune disease, and candidiasis syndrome.

Optimal management of the ocular and systemic components of the multiple endocrine deficiency, autoimmune disease, candidiasis syndrome requires early identification of affected individuals. This autosomal recessive syndrome is characterized by hypoparathyroidism, Addison's disease, and chronic mucocutaneous candidiasis among other endocrinopathies and immune disorders. We retrospectively reviewed 16 patients, 14 with the full syndrome and two with the syndrome partially manifested. Four of these patients manifested a self-limited, bilateral keratitis in which the age of onset ranged from 2 to 9 years. Keratitis preceded the onset of any endocrinopathy in two of four patients and was among the first signs of the syndrome. The keratitis was not caused by hypoparathyroidism or candidiasis. The anterior stromal vascularization and scarring resulted in a visual acuity of 20/50 or worse in four of eight affected eyes. We recommend medical management of the corneal disease without surgical intervention.

Addison Disease↗
PubMed1987

Controversies concerning the safety of estrogen replacement therapy.

Unopposed estrogen replacement is known to cause endometrial carcinoma in a small percentage of postmenopausal women, but the effects on ovarian and breast tissue remain uncertain. The increased risk of endometrial carcinoma seems to be related to both the dosage and duration of unopposed estrogen treatment. Until very recently, the morbidity and costs that result from the need for endometrial biopsy because of abnormal bleeding and from the need for hysterectomy due to hyperplasia have been ignored, but recent data suggest that they are likely to be considerable. Progestogens are known to protect against endometrial hyperstimulation, but the optimal duration of therapy each month and the maximally protective agent and dose remain to be determined. Estrogen replacement therapy may reduce the risk of arterial disease; however, the comparative effects of the various preparations, as well as their respective mechanisms of action, must be subjected to further study.

Breast Neoplasms↗
PubMed1987

Aggressive behavior.

This article considers the major fighting-related activities of the most common food animals. Instead of being seen as a largely pathologic phenomenon born solely of frustration and pain, aggressive behavior is now regarded as a natural part of an animal's behavioral equipment for survival and reproduction. There is a need, spurred by consideration for both productivity and animal well-being, to understand the fundamentals of the aggressive behavior of domestic species so that one can accommodate for this behavior in systems of livestock management.

Aggression↗