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Biomedical subjects

G H Anderson

Publications and source records attributed to G H Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effects of essential amino acids on food and water intake of rats.

This study examined the effects of selected groups of essential amino acids (EAAs), given by gavage, on short-term food and water intake. Amino acid groups were selected on the basis of their common physiologic functions in relation to current hypotheses on the role of amino acids in food intake control, and the quantities given were based on the proportions in 1.5 g of the EAA content of albumin. The complete EAA mixture (1.5 g) suppressed food intake by an average of 60 and 37% during the 1st and 2nd h of feeding, respectively, but had no influence on feeding in the subsequent 12 h. Total daily (14 h) intake was decreased by 9%. With the exception of the aromatic amino acid (Phe + Tyr + Trp, 0.34 g) group, all groups significantly decreased food intake by a comparable magnitude (32%) during the 1st h. In this time period, rats given the EAAs, Arg + Met + Val (0.38 g), and Arg + His + Lys (0.44 g) mixtures increased their water intake, whereas intake by rats given the Phe + Tyr + Trp + Thr (0.46 g) and Ile + Leu + Val (0.45 g) mixtures was unchanged. Thus, the food intake suppression caused by EAAs was not accounted for by an equal effect of its component amino acid groups. As well, food intake suppression by amino acid groups was not explained by increased water consumption, nor was it simply related to the quantity of nitrogen provided by the treatment.

Amino Acids, Essential↗
PubMed1994

Dissociation between plasma and brain amino acid profiles and short-term food intake in the rat.

The relationship between plasma and brain amino acids and short-term food intake after administration of albumin, or its constituent amino acids, was examined. Rats given protein (0.85 g chicken egg albumin) or an amino acid mixture patterned after egg albumin reduced their food intake during 1 h of feeding beginning 30 min after gavage. Similarly, when given separately, the essential (EAA) and nonessential amino acid (NEAA) fractions of egg albumin caused comparable decreases in food intake. As the dose increased from 0.5 to 1.5 g the duration of anorexia prolonged to 12 h. Little change occurred in plasma amino acids at 30 and 60 min after albumin at 0.85 g, although many increased by 25-50% at 60 min after 1.5 g. Marked changes in plasma occurred after gavage with the total mixture of constituent free amino acids and after either EAA or NEAA fractions. Brain amino acid concentrations were little affected by albumin and did not show consistent changes after the amino acid treatments. Thus the reductions in food intake after ingestion of albumin or of its constituent amino acids were not predicted from the resulting changes in either plasma or brain concentrations of amino acids.

Administration, Oral↗
PubMed1994

Insulin-like growth factor-I and insulin have no differential effects on glucose production and utilization under conditions of hyperglycemia.

We have previously shown that in moderately hyperglycemic depancreatized dogs, a glucose-lowering infusion of insulin-like growth factor-I (IGF-I) increased glucose utilization and lactate more, and suppressed glucose production and lipolysis less, than an equipotent glucose-lowering dose of insulin. Similar differences have been observed by others in nondiabetic and diabetic rats. To determine whether the decline in glycemia was important in detecting differential effects of IGF-I and insulin on glucose turnover, IGF-I (0.43 micrograms/kg.min; n = 6) or insulin (0.9 mU/kg.min; n = 9) were infused for 180 min, while hyperglycemia (approximately 180 mg/dl) was maintained. The decline of plasma glucose specific activity was minimized by using the matched step tracer infusion ([6-3H]- and [2-3H]glucose) method. Our results confirmed the approximately 10% potency of IGF-I on glucose metabolism compared to insulin and the lack of effect of IGF-I on insulin clearance. Under conditions of hyperglycemia, the glucose turnover findings were unexpected; there was no difference in the inhibition of glucose production (difference from basal, 2.7 +/- 0.4 mg/kg.min with IGF-I and 2.4 +/- 0.2 with insulin) or the stimulation of glucose utilization (difference from basal, 4.5 +/- 0.8 mg/kg.min with IGF-I and 4.7 +/- 1.3 with insulin). However, lactate increased more (P < 0.01) with IGF-I (from 1230 +/- 163 to a peak of 1903 +/- 349 microM) than insulin (from 1209 +/- 291 to 1535 +/- 340 microM) despite the same increment in glucose utilization. FFA and glycerol declined more with insulin, but the difference was not significant. IGF-I and insulin suppressed plasma amino acids to an equivalent extent. We concluded that 1) the differential effects of IGF-I and insulin on glucose turnover are masked under conditions of hyperglycemia; and 2) because insulin and IGF-I induced the same increment in glucose utilization, but lactate increased more with IGF-I, IGF-I might affect intracellular glucose metabolism differently from insulin. The failure of IGF-I to induce greater glucose utilization than insulin during hyperglycemia, the greater rise in lactate with IGF-I treatment, and the absence of differential effects on proteolysis indicate that IGF-I might have only limited clinical application in the treatment of diabetes.

Animals↗
PubMed1994

Internal fixation or hemiarthroplasty for undisplaced fractures of the femoral neck in octogenarians.

We compared the reoperation rate after internal fixation for minimally displaced or impacted intracapsular fractures of the femoral neck in patients aged 80 years and above with that in similar patients aged 65 to 79 years. We also compared the results of internal fixation with those of hemiarthroplasty for displaced intracapsular fracture in an age- and sex-matched group of elderly patients. We found that a significantly greater proportion of the older patients treated by internal fixation required reoperation than either the younger group or the age-matched group treated by hemiarthroplasty. Our results indicate that internal fixation may not be the best treatment for extremely elderly patients with minimally displaced or impacted intracapsular fractures of the femoral neck.

Aged↗
PubMed1993

Consuming aspartame with and without taste: differential effects on appetite and food intake of young adult males.

Despite some reports that aspartame (APM)-sweetened beverages may increase subjective appetite, previously we demonstrated that drinking 280 ml of an APM-sweetened soft drink (170 mg APM) had no effect on appetite, and 560 ml of the same soft drink (340 mg APM) reduced appetite. The present study examined this appetite reduction to determine its cause. Eighteen normal weight young adult males received five treatments (beverage preloads) at 1100 h in a randomized order, one per week: 280 ml of carbonated mineral water (CMW) (control), 560 ml of CMW, 280 ml of CMW with 340 mg of encapsulated APM, 280 ml of CMW sweetened with 340 mg APM, 560 ml of an APM-sweetened soft drink (340 mg APM). Subjective hunger and food appeal were measured from 0930 a.m. to 1230 h, and food intake from a buffet lunch offered at 1205 h was measured. Treatment had no effect on food intake or macronutrient selection. Both 560 ml of CMW or soft drink suppressed appetite, although 280 ml of APM-sweetened mineral water significantly increased subjective appetite relative to the control. Encapsulated APM had no effect on appetite. Therefore, appetite reduction following consumption of an APM-sweetened drink is likely due to drink volume and not the APM content. In addition, consuming APM-sweetened CMW produces a short-term increase in subjective appetite.

Adult↗
PubMed1993

Increased prevalence of cardiovascular complications in women with furosemide resistant essential hypertension.

Patients with essential hypertension (n = 2969) who had not been taking any blood pressure medication for longer than 1 week were classified as furosemide-sensitive (FS) if their diastolic BP after furosemide fell > or = 10% and furosemide-resistant (FR) if it fell less than that. The FS group was significantly (P < or = .05) older, and had higher blood pressure than the FR group. In patients over age 50, the prevalence of cardiovascular complications (myocardial infarction, stroke, angina, congestive heart failure, and intermittent claudication) in the FR group (12.3%) was significantly (P = .0039) more than in the FS group for all patients, and especially for women (P = .0053). This was not explained by plasma renin activity, plasma norepinephrine, obesity index, cholesterol, blood sugar, or smoking history, and was associated in the FR group with a lower BP. This study characterizes the furosemide response of BP in hypertensive subjects and demonstrates an increased prevalence of cardiovascular complications in women over age 50 in the furosemide resistant group.

Adult↗
PubMed1993

The incidence of proximal femoral fractures in an English county.

We have studied the incidence of fractures of the proximal femur in one English county from 1968 to 1991. Numbers have increased steadily, but the age-specific incidence has remained relatively unchanged since 1981. The increase is due to the rise in the population most at risk; this is likely to continue causing a 20% increase in demand for treatment by the year 2000. Suitable allocation of resources must be planned.

Age Factors↗
PubMed1993

Preoperative skin traction for fractures of the proximal femur. A randomised prospective trial.

We report the results of a randomised trial to determine the effects of skin traction on 252 patients awaiting surgery for fractures of the proximal femur. They were allocated randomly to be nursed free in bed or to receive Hamilton-Russell skin traction. No differences were found between the groups in terms of pain suffered, analgesia required, frequency of pressure sores or ease of operation. The application of skin traction to patients with fractures of the upper femur is time-consuming and we recommend therefore that its routine use should be discontinued.

Adult↗
PubMed1993

An animal model for the study of amino acid metabolism in uremia and during peritoneal dialysis.

We tried to determine the suitability of the rabbit as an animal model to study amino acid (AA) metabolism in continuous ambulatory peritoneal dialysis. We also measured the effect of intraperitoneal (ip) infusion of AA on blood AA changes and food consumption. Plasma AA levels were measured in 10 normal rabbits after an overnight fasting and 30, 60, and 120 minutes after a meal. Following these baseline observations, rabbits were randomly divided into two groups. One group of five rabbits was made uremic after surgical partial nephrectomy, whereas the remaining (controls) underwent sham operations. Two weeks after the induction of uremia we measured the effect of chronic renal failure on fasting and postprandial (30, 60, 120 minutes) plasma AA levels. Upon the completion of the second experiment (4 weeks after the induction of uremia) we studied the effect of an ip AA on plasma AA profile 1, 2, 4, and 6 hours after the infusion in both uremic and control rabbits. We also measured the food intake in all experiments. The results of our experiments showed the following: 1. plasma AA in the rabbits decreased after induction of chronic renal failure and increased after food ingestion and ip infusion of AA solution; 2. neither induction of uremia nor ip AA infusion have an effect on food consumption; 3. the majority of the alterations in plasma AA levels we observed in the uremic rabbits were similar to those observed in humans, indicating that the rabbit may be a suitable model for the study of AA metabolism in chronic renal failure and during peritoneal dialysis.

Amino Acids↗
PubMed1992

Estimation of possible impact of non-caloric fat and carbohydrate substitutes on macronutrient intake in the human.

This paper addresses the expected impact of use of macronutrient substitutes by individuals without strong motivation to control macronutrient or energy intake when such modified foods serve as replacements of foods normally ingested rather than as "add-ons". A basic premise of the paper is that individuals are likely to replace a substantial part of the energy equivalent of the original substitution. It further assumes that the macronutrient composition of the additional foods consumed will reflect normal food selection behaviours. The paper derives a description of the expected selection behaviour from examination of the within subject variance in energy and macronutrient intake of 29 subjects followed for 365 consecutive days (the Beltsville One Year Dietary Intake Study). Patterns observed in these subjects were validated through examination of associations between macronutrient intake and energy intake in 600 women, each of whom contributed 6 days of dietary data (USDA CSFII-85). As presently proposed the model suggests that the use of non-caloric fat replacements, by subjects without strong motivation to control fat or energy intake, can be expected to result in a net decrease (less than original substitution) in fat intake and net increases in carbohydrate and protein intakes. Conversely, use of carbohydrate replacements in core foods can be expected to result in net increases in fat and protein intakes and a partial decrease in carbohydrate intake. The magnitude of these net changes is seen to be a function of the extent of replacement of energy.

Adult↗
PubMed1992

A comprehensive program for cervical cancer detection and management.

OBJECTIVE: The purpose of this study was to document some of the results of a comprehensive provincial cytology and colposcopy program for the year 1988 and also to review the impact on the incidence and mortality rates for a clinical carcinoma of the cervix. STUDY DESIGN: This study is a retrospective analysis of the cytologic results of all patients examined provincially in 1988 and a review of the clinical records of patients diagnosed with invasive cancer and those who died of disease. RESULTS: In 1988 490,985 women (40% of all women over the age of 15 in the population) were screened, with 9.2% showing abnormal cells. A total of 79% of women screened were less than 50 years old and accounted for 86.3% of all abnormal smears. Women less than 35 years old were more likely than older women to have moderate dyskaryosis or worse. CONCLUSION: Intensive comprehensive cytology and colposcopy programs reduce not only the incidence and mortality of clinical carcinoma of the cervix but also rates of in situ disease and other precursors.

Adult↗
PubMed1992

Human papillomavirus infection of the uterine cervix. Tissue sampling and laboratory methods affect correlations between infection rates and dysplasia.

Two common tissue sampling techniques--colposcopic biopsy and cervical scrape--and two common human papillomavirus (HPV) detection techniques--Southern blot and dot blot (SB and ViraPap [VP])--were compared to determine whether differences in these techniques alter correlations between "oncogenic" HPVs and cervical neoplasia. In 87 women with persistently abnormal Papanicolaou (Pap) smears, concurrent biopsy and scrape specimens contained HPV in 21 (24%) and contained no HPV in 26 (30%); 30 scrape specimens (34.5%) tested positive when the biopsy tested negative and 10 (11.5%) scrape specimens tested negative when the biopsy tested positive (overall concordance, 54%). Concordance for the most prevalent HPVs (16/18) was 59%. In carcinoma in situ, HPV was found in biopsy samples significantly more frequently than in scrape specimens: 17 of 23 (75%) biopsy samples versus 9 of 23 (39%) scrape specimens (P = 0.018). Conversely, in mild or no dysplasia, 0 of 42 biopsy samples tested positive for HPV 16/18 compared with 12 of 42 scrape specimens (29%; P = 0.0001). Of 229 specimens analyzed by SB and VP, 43 (19%) tested positive and 148 (65%) tested negative for HPV by both methods (concordance, 84%). Corroborative results indicated that 29 of 35 (83%) VP-positive SB-negative results were truly positive compared with none of three SB-positive VP-negative results. Both the cervical sampling technique and the method for HPV detection can significantly affect statistical correlations between cervical dysplasia and HPV type.

Biopsy↗
PubMed1992

Route of administration of tryptophan and tyrosine affects short-term food intake and plasma and brain amino acid concentrations in rats.

The effects of route of administration of tryptophan and tyrosine on food intake and diet selection and on plasma and brain tryptophan or tyrosine concentrations were studied. Tryptophan and tyrosine given intraperitoneally at 100 mg/kg body wt suppressed food intake by 33-45% over a 2-h feeding period beginning 30 min after injections. No preferential effect was shown for either the high carbohydrate or high protein diet choice. When given intragastrically at this dose, neither tryptophan nor tyrosine affected food intake. Tryptophan, but not tyrosine, at 200, 400 and 600 mg/kg body wt given intragastrically reduced food intake and carbohydrate diet intake by an average of 20 and 25%, respectively, in the first 2 h of feeding. Plasma and brain tryptophan were higher for 30 min following intraperitoneal tryptophan injections than after tryptophan given intragastrically at 100 mg/kg body wt. However, intraperitoneal tyrosine (100 mg/kg body wt) resulted in higher plasma tyrosine levels at 5-10 min but lower levels at 30 min than when tyrosine was given intragastrically. Brain tyrosine was higher after intraperitoneal treatment only at 10 min and was similar to intragastric treatment at other times. When these amino acids were given intragastrically at 400 mg/kg body wt, higher plasma tryptophan, plasma tyrosine and brain tyrosine were found than following intraperitoneal injection of the behaviorally effective dose (100 mg/kg body wt) at 30 min. Thus the reduced effect on food intake of tryptophan or tyrosine given intragastrically compared with intraperitoneally is not readily explained by their lower concentrations in plasma and brain preceding and at the time that the rats had access to food.

Administration, Oral↗
PubMed1992

Secondary hypertension. An overview of its causes and management.

Primarily hypervolaemic, high output forms of hypertension, with features indicating or strongly suggesting fluid overload as the cause of elevated cardiac output, resulting from renal disease with reduced glomerular filtration rate causing sodium retention, renal tubular causes of sodium retention, greatly excessive sodium intake and low renin hypertension, can be treated by reduction of sodium intake and potentiation of its excretion by diuretic therapy, removal of the cause (e.g. aldosteronoma), and calcium antagonists. Excessive vasoconstriction resulting from noradrenaline (norepinephrine) in neurogenic hypertension, phaeochromocytoma, orthostatic hypertension and alpha-adrenergic drug administration; angiotensin excess due to renal ischaemia brought about by aortic coarctation, renal arterial and arteriolar stenosis, intraluminal obstruction, external renal compression, renin-producing tumours, intrinsic kidney diseases and excessive renin substrate; and vascular structural disorders such as atherosclerosis, arteriolitides and fibrosis with or without calcification of major arteries may also induce hypertension. Secondary hypertension of uncertain mechanism may occur in hyperparathyroidism, hyper-or hypothyroidism, or acromegaly. All are best treated by appropriate correction of the endocrine excess or deficiency. It may also occur in pregnancy, where the mechanism may involve prostaglandin-thromboxane imbalance or calcium deficiency; calcium deficiency with some evidence of benefit from calcium supplements; and the recumbent hypertension paradoxically associated with autonomic failure. Excellent responses to specific correction of the underlying cause or pathogenetic mechanism is usual in young individuals but less frequent in older patients.

Cardiac Output, High↗
PubMed1992

Invasive cancer of the cervix in British Columbia: a review of the demography and screening histories of 437 cases seen from 1985-1988.

The charts of 437 patients with newly diagnosed invasive cervical cancer seen in British Columbia during 1985-1988 were reviewed to determine the age at diagnosis, stage of disease, and histology of the lesions. The patient's immigration status and country of birth were also examined. Two hundred forty-two patients (55%) were age 50 or over and 149 (34%) had preclinical stage IB disease. One hundred seventy of these patients (39%) had never had a cytologic examination before presenting with clinical symptoms, and 45 additional patients had not had cytology for 5 or more years before presenting with invasive disease; thus, a total of 215 cases (49%) fell into the category of "no cytology or cytology longer than 5 years ago." All negative smears were reviewed and in 39 patients (15%) having previous cytology, abnormal cells had been missed or undercalled. Native Indian women made up 10% of the cases of invasive carcinoma, a disproportionately large number as they represent only 2% of the British Columbian population. Of the 27 Native Indian patients in this series, 16 (59%) had never had a cytologic examination. Eighty-five (30%) of 276 women born in Canada had never had a cytologic examination, compared with 34 (71%) of 48 immigrants resident in the country for fewer than 10 years. Twenty-four patients were over the age of 60 with a history of negative Papanicolaou smears. We conclude that, if further gains are to be made in the reduction of death rates from invasive cervical carcinoma, new means must be found to encourage women to participate in Papanicolaou smear screening programs. In particular, special efforts must be made to attract specific groups, such as the Native Indian population and older recent immigrants.

British Columbia↗
PubMed1992

Delayed orthostatic intolerance.

In seven patients who presented with lightheadedness, fatigue, "weakness," and sometimes syncope, blood pressure was found not to fall after standing for 3 to 4 minutes but to fall severely, frequently with syncope or presyncopal symptoms, after 13 to 30 minutes when measured every minute with an automatic device. This delayed orthostatic hypotension could be corrected with inflation of a pressure suit to 45 mm Hg. Its mechanism was further investigated with measurements of plasma catecholamines, plasma cortisol and aldosterone responses to corticotropin, and the effects of norepinephrine infusions on blood pressure and venous contractility. There was normal or excessive orthostatic norepinephrine release in all patients, evidence of impaired venous innervation in the legs in some, and various disorders in the other patients. Since therapeutic improvement in the orthostatic hypotension greatly reduced the symptoms, we concluded that orthostatic hypotension occurring after more than 10 minutes of standing is a potentially debilitating and often correctable disorder.

Adrenal Cortex Function Tests↗
PubMed1991

Carcinoid tumour of the gastrointestinal tract: prognostic factors and disease outcome.

This study represents retrospective analysis of 87 patients with a carcinoid tumour of the gastrointestinal tract seen and followed in the British Columbia Cancer Agency (BCCA) from 1960 to 1986. In 49 cases, the primary site was the small bowel. The rest of the cases were distributed as follows: 11 appendix, 10 rectum, 5 stomach, and 7 undetermined. We extrapolated the Dukes' and modified Astler-Coller surgicopathological classifications used for colorectal cancer for use in our cases of carcinoid tumour of the gastrointestinal tract. A strong correlation was found, using this staging, with disease-specific survival. Other prognostic factors included histologic differentiation, the presence of macroscopic residual disease after initial surgery, and level of 5-hydroxyindoleacetic acid (5-HIAA) in urine. Among 51 patients with surgically grossly removed disease, there was a tendency for the development of distant and distant/locoregional recurrence more often than locoregional recurrence alone. The liver was the commonest site of distant recurrence. Analysis of the effect of radiotherapy or chemotherapy on carcinoid tumour of the gastrointestinal tract proved unsuccessful because only a small portion of the patients had this treatment, and it was used mainly for palliation.

Adult↗