Biomedical subjects

G W Reed

Publications and source records attributed to G W Reed.

At least 55 records · Page 3Linked to original sources

PubMed1993

Weight cycling: a review of the animal literature.

This review critically evaluates the animal literature concerning the effects of weight cycling on factors related to development of obesity, diabetes, hypertension, and hyperlipidemia. Although human studies have been used to retrospectively examine the relationship between fluctuations in body weight and a variety of disease markers, direct causal links between weight cycling and negative health effects have been inferred from a series of scientific publications using animals as subjects. We use data from 24 such publications to evaluate evidence for and against a series of hypotheses that have been suggested regarding weight cycling and health. Although there are some intriguing results, there is currently little evidence to support any of these hypotheses. However, methodological limitations were identified in many of these studies, and caution should be used in making definitive decisions about weight cycling. Weight cycling studies could be improved by including more appropriate controls, comparing controls to weight cycling animals at more appropriate time points, and giving more attention to potential effects of diet composition. While more careful research is needed, at this time we conclude that the published animal literature does not justify any warnings about the hazards of weight cycling.

Adipose Tissue↗

PubMed1993

Insulin action in rats is influenced by amount and composition of dietary fat.

The chronic influence of dietary fat composition on obesity and insulin action is not well understood. We examined the effect of amount (20% vs 60% of total calories) and type (saturated vs polyunsaturated) of fat on insulin action and body composition in mature male rats. Six months of feeding a high fat (HF) diet led to obesity and impaired insulin action (determined by a euglycemic-hyperinsulinemic clamp), neither of which were reversed by a subsequent 6 months of feeding a low fat (LF) diet. Within HF fed rats, type of fat did not affect body composition or insulin action. Six months of feeding a low fat diet led to only a slight decline in insulin action, with no difference due to type of dietary fat. From 6-9 months, insulin action became more impaired in LF rats fed the saturated diet than in LF rats fed the polyunsaturated diet. By 12 months, all groups were obese and had a similar impairment in insulin action. The amount and type of fat in the diet did not influence the overall degree of impairment in insulin action but did affect the time course. Both feeding a high fat diet and feeding a low fat saturated diet accelerated the impairment in insulin action relative to rats fed a low fat polyunsaturated fat diet.

Adipose Tissue↗

PubMed1993

Intraobserver and interobserver variability of the amniotic fluid index.

OBJECTIVE: We assessed intraobserver and interobserver variations in the performance of the amniotic fluid index. STUDY DESIGN: A total of 34 women in the third trimester with intact membranes were examined twice by each of three examiners. The amniotic fluid index was measured once by each of the three examiners in order, then repeated by each examiner in the same order. Numeric displays on the video terminal screen were covered so that the examiners were blinded to actual measurement values. Results were recorded on hard copy for later data analysis. A senior investigator supervised all examinations to monitor consistency of technique. RESULTS: Overall, the coefficient of variation for amniotic fluid index measurements varied from 10.8% within examiners to 15.4% between examiners. Both between and within variation of absolute differences increased as the amniotic fluid index value increased, while the percent difference decreased. Simply repeating the test by the same examiner will decrease the coefficient of variation significantly. CONCLUSION: Although intraobserver and interobserver variability cannot be eliminated, its impact can be minimized by use of the same examiner for serial studies.

Amniotic Fluid↗

PubMed1993

Chorionic villus sampling: quality control--a continuous improvement model.

OBJECTIVE: Our purpose was to describe Vanderbilt University Medical Center's experience in establishing a chorionic villus sampling program and the importance of quality control along with a continuous improvement model on the first 1000 cases. STUDY DESIGN: A continuous improvement model was established with emphasis on a multidisciplinary team approach and quality assurance process. A computerized data base was used for continuing analysis of complications and for allowing facile access to pertinent information. RESULTS: A continuous improvement model allowed for an improved process and outcome for patients, personnel, and referring health care providers. Follow-up for initial symptoms after chorionic villus sampling was obtained on 98.5% of patients. Pregnancy follow-up, including birth data, was obtained on 93%. CONCLUSION: A continuous improvement mode from the project's onset resulted in an improved process and outcome, information helpful for accessing spontaneous abortion rates and pregnancy outcomes (including the incidence of limb abnormalities and factors associated with abortions) and recommendations for training personnel.

Abortion, Spontaneous↗

PubMed1993

Long-term visual results and complications in children with aphakia. A function of cataract type.

PURPOSE: Previous studies of outcome in children with aphakia have approached the data by grouping patients according to features such as age at surgery, type of procedure, or some other common attribute. The purpose of this study is to identify factors predictive for visual outcome and complications in pediatric patients with cataracts. METHOD: One hundred seventy-four eyes in 118 patients underwent lensectomy and anterior vitrectomy for congenital or juvenile cataracts. All received early optical correction, occlusion therapy when necessary, and follow-up for at least 6 months. Visual outcome and complications were analyzed statistically to determine predictive factors. Features analyzed included cataract type, laterality, age at onset, follow-up, and corneal size. RESULTS: Statistical analysis showed that the most important predictor of long-term visual outcome and complications is cataract type. Visual outcome differed significantly by cataract type, with best results in the lamellar and posterior lentiglobus groups. Unilateral cases had a mean acuity lower than bilateral cases. Other factors, such as age at surgery and corneal size, were less predictive but closely linked to cataract type. Complications, such as aphakic glaucoma, also were more closely linked to the type of cataract than to other variables. CONCLUSION: The results indicate that an important determinant of long-term outcome and complications in aphakic children is cataract type. Other features were found to be closely correlated to cataract type and were not independently significant.

Age Factors↗

PubMed1993

Comparative trial of large-particle aerosol and nose drop administration of live attenuated influenza vaccines.

Healthy adult subjects (n = 198) were randomized to receive bivalent cold-adapted (ca) influenza A vaccine containing 10(7.4) TCID50 each of A/Kawasaki/9/86 (H1N1) and A/Los Angeles/2/87 (H3N2) by either nose drops (ND) or large-particle aerosol (LPA). All subjects had received monovalent inactivated influenza B vaccine intramuscularly in the previous year. Ninety percent of LPA recipients and 82% of ND recipients preferred intranasal administration to their previous experience with intramuscular vaccine. Twenty-six (27%) of 98 LPA recipients and 47 (49%) of 97 ND recipients reported swallowing vaccine (P = .008). Fever was observed uncommonly (< or = 5%), and incidence of respiratory symptoms was comparable between groups. Fourfold or greater hemagglutination antibody response to at least one of the influenza A vaccine viruses was significantly more frequent after LPA (64%) than ND vaccination (43%; P = .005). LPA administration of ca influenza to the nasopharynx was well tolerated, safe, and more immunogenic than ND delivery.

Administration, Intranasal↗

PubMed1993

Serum angiotensin converting enzyme in diabetic patients.

Serum angiotensin converting enzyme (ACE) levels are higher in patients with diabetes mellitus than in many others. Techniques are available to grade different degrees of diabetic retinopathy, which can demonstrate a relationship between ACE and diabetic retinopathy. In this study, patients with diabetic retinopathy had higher serum ACE levels (6.3 +/- 0.2) than nondiabetic patients (4.3 +/- 0.5) (p < 0.001). In addition, the mean serum ACE level in diabetic patients with nonproliferative retinopathy (5.55 +/- 0.4) was less than that in diabetic patients with proliferative retinopathy (6.63 +/- 0.25) (p = 0.02). Due to the variability in individual serum ACE levels and the frequent use of ACE inhibitors by hypertensive diabetics, these techniques are not suitable for retinopathy screening programs. However, the graded relationship demonstrated by these data may have relevance for the pathophysiology of diabetic retinopathy.

Adult↗

PubMed1993

Teenagers' perceptions of barriers to prenatal care.

A structured interview conducted during the postpartum hospitalization of 184 patients aged 17 years or younger was used to study teenagers' perceptions of barriers to prenatal care. The interview consisted of more than 100 questions on demographic characteristics, family and social support, desire for the pregnancy, perceptions of the importance of prenatal care, practical obstacles to access to health care (such as lack of transportation, day care, etc), financial problems related to care, problems finding time to obtain health care, knowledge of available prenatal care resources, and perceptions of ease or difficulty in the use of existing clinics. Multiple regression analysis using the Kessner index as the criterion variable showed that major factors related to the adequacy of prenatal care received by these teenagers were perceptions of cost barriers, the gestational age at which the teenager discovered she was pregnant, school enrollment status (those in school received poorer care than those who had dropped out), and the degree of social support experienced by the teenager. These findings suggest that specific changes in the health care system are needed to make prenatal care more accessible for pregnant teenagers. These changes would include enhancing community awareness that Medicaid pays for prenatal care, establishing links between prenatal clinics and school health systems, and scheduling prenatal clinics at times more convenient for teenagers.

Adolescent↗

PubMed1993

Effects of weight cycling in rats allowed a choice of diet.

We examined the effects of weight cycling, produced by bouts of weight loss and regain, on body weight, body composition, dietary fat intake, and energy efficiency. Three groups of adult female Wistar rats were followed for 116 days: control rats (n = 10) were allowed ad libitum access to three mixed diets with protein as a constant proportion of energy and fat provided at 10, 30, and 50% of energy; cycled rats (n = 10) had four bouts of food restriction (50% of baseline intake for 10 days) and refeeding (18-20 days of ad libitum access to the 3 mixed diets); maturity controls (n = 10) were treated identically to controls during the first two cycles and identical to cyclers during the final two weight cycles. At the end of the experiment, we could identify no negative effects of weight cycling on any of the measures taken, and in fact body weight and percentage body fat were lower in cyclers than controls. Dietary fat intake was not altered by weight cycling. In summary, weight cycling did not promote body weight or body fat gain.

Animals↗

PubMed1993

A review of the results of laparoscopic versus open appendectomy.

Proponents of laparoscopic appendectomy emphasize the advantages of laparoscopic operation--decreased hospitalization, paralytic ileus, postoperative pain and wound complications, including infection. This study compared open laparoscopic appendectomy with laparoscopic appendectomy. To compare the two techniques, patients undergoing laparoscopic appendectomy at four hospitals were compared with patients undergoing open appendectomy during a six month period. Excluded were incidental appendectomies and patients with perforated appendicitis. An equal number of pediatric patients undergoing laparoscopic and open procedures were included in the analysis to avoid bias, because most of the laparoscopic appendectomies were performed in the adult patient population (age of more than 16 years). A University Medical Center, a Veterans Administration and two community hospitals were the settings. Patients undergoing laparoscopic appendectomy (n = 54) had an average age of 25.7 +/- 1.5 (range of six to 59 years). These patients were compared with 121 patients undergoing open appendectomy whose average age was 23.7 +/- 1.8 (range of three to 83 years). The race and gender distribution were similar in the two groups. Traditional open appendectomy was compared with a group of patients undergoing laparoscopic appendectomy. Variables evaluated were operating room time, number of patients who reported nausea, days until patient tolerated a regular diet, days of hospitalization, postoperative pain medication and wound infection rate. Results are expressed as the mean plus or minus standard error of the mean. Analysis of variance was used to compute continuous variables and Fischer's exact test was used for discrete variables. The laparoscopic approach was attempted in 61 patients and completed in 54 patients. Open appendectomy was performed upon 121 patients. Nineteen patients (18 who underwent open operation and one patient who underwent laparoscopic operation) were excluded from further analysis because of perforated appendicitis. The open procedure took less time (p < 0.05). However, there were more wound infections than in the laparoscopic group (seven of 103 versus zero of 53; p = 0.09). Patients with acute appendicitis recuperated more quickly from the laparoscopic procedure, as evidenced by the time until eating regular diet, period of hospitalization, incidence of nausea and pain medications on postoperative day one (p < 0.05). The absence of wound infections after laparoscopic appendectomy can be attributed to the practice of placing the appendix in a sterile bag or into the trocar sleeve before removal from the abdomen. Laparoscopic appendectomy reduces the period of hospitalization, postoperative ileus, nausea and postoperative pain in patients with acute appendicitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1992

The effects of acute elevations in plasma cortisol levels on alanine metabolism in the conscious dog.

The present study was undertaken to determine whether an acute physiological increase in plasma cortisol level had significant effects on alanine metabolism and gluconeogenesis within 3 hours in conscious, overnight-fasted dogs. Each experiment consisted of an 80-minute tracer and dye equilibration period, a 40-minute basal period, and a 3-hour experimental period. A primed, continuous infusion of [3-3H]glucose and continuous infusions of [U-14C]alanine and indocyanine green dye were initiated at the start of the equilibration period and continued throughout the experiment. Dogs were studied with (1) a hydrocortisone infusion ([CORT] 3.0 micrograms.kg-1.min-1, n = 5), (2) hydrocortisone infused as in CORT, but with pancreatic hormones clamped using somatostatin and basal intraportal replacement of insulin and glucagon (CLAMP+CORT, n = 5), or (3) saline infusion during a pancreatic clamp (CLAMP, n = 5). Glucose production and gluconeogenesis were determined using tracer and arteriovenous difference techniques. During CLAMP, all parameters were stable except for a modest 67% +/- 6% increase in gluconeogenic conversion of alanine to glucose and a 53% +/- 26% increase in gluconeogenic efficiency. When plasma cortisol levels were increased fourfold during CLAMP+CORT, there was no change in the concentration, production, or clearance of glucose. Gluconeogenic conversion of alanine to glucose increased 10% +/- 34% and gluconeogenic efficiency increased 65% +/- 43%, while net hepatic alanine uptake (NHAU) increased 60% +/- 19% and hepatic fractional extraction of alanine increased 38% +/- 12%. Cortisol did not cause an increase in the arterial glycerol level or net hepatic glycerol uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗

PubMed1992

Nutrient balance and energy expenditure during ad libitum feeding of high-fat and high-carbohydrate diets in humans.

To study the influence of diet composition on regulation of body weight, we fed 21 weight-stable subjects (11 lean, 10 obese) high-carbohydrate (HC) and high-fat (HF) diets for 1 wk each. Although diet composition was fixed, total energy intake was unrestricted. Subjects had a higher energy intake on the HF (11,039 +/- 2700 kJ/d) than on the HC (10,672 +/- 2617 kJ/d) diet (P less than 0.05), but energy expenditure was not different between diets. On day 7 of the HC diet, carbohydrate (CHO) oxidation was significantly related to CHO intake with the slope of the regression line 0.99, suggesting that overall CHO balance was near zero. However, the slope of the regression line was greater for obese than for lean subjects. On day 7 of the HF diet, fat oxidation was significantly related to fat intake but the slope of the line was 0.50, suggesting that overall fat balance was positive. However, this relationship was due entirely to lean subjects, with obese subjects showing no relationship between fat intake and oxidation.

Adult↗

PubMed1992

Short-term effects of dietary-fat ingestion on energy expenditure and nutrient balance.

Joule for joule, dietary fat may promote obesity more than protein or carbohydrate. In this study we determined whether the addition of 50 g dietary fat to a standard breakfast would increase energy expenditure or fat oxidation during the immediate 6-h postprandial period or over the ensuing 18 h. We also determined whether subjects with a high level of aerobic physical fitness would show a greater increase in fat oxidation after the ingestion of the extra fat than would less fit subjects. Adding fat did not increase fat oxidation or energy expenditure either during the immediate 6-h postprandial period or over the following 18 h. This was true regardless of the subject's fitness level. Acutely, dietary fat ingested in excess of its usual rate of oxidation appears to be stored in the body. Being physically fit does not appear to provide an advantage in avoiding short-term storage of excess dietary fat.

Adult↗

PubMed1992

Base deficit stratifies mortality and determines therapy.

OBJECTIVE: To determine the association of base deficit with mortality and other factors affecting mortality. DESIGN: Retrospective review. SETTING: Tertiary care center. PARTICIPANTS: Consecutive samples of 3791 trauma patients admitted with an arterial blood gas sample taken in the first 24 hours. MAIN OUTCOME MEASURES: Age, injury mechanism, head injury, shock (systolic blood pressure less than 90 mm Hg), Revised Trauma Score, TRISS probability of survival Ps, and mortality. RESULTS: Most (3038) patients (80.1%) exhibited a base deficit. Base deficit, age, injury mechanism, and head injury were associated with mortality using logistic regression. Age less than 55 years, no head injury, and a base deficit of -15 mmol/L were associated with 25% mortality. Age greater than or equal to 55 years with no head injury or age less than 55 years with a head injury and a base deficit of -8 mmol/L were associated with a 25% mortality. When shock was added to the model, all factors remained significant, and base deficit was supplemental to blood pressure. Base deficit also added significantly to the Revised Trauma Score and TRISS measurements. CONCLUSIONS: The base deficit is an expedient and sensitive measure of both the degree and the duration of inadequate perfusion. It is useful as a clinical tool and enhances the predictive ability of both the Revised Trauma Score and TRISS.

Academic Medical Centers↗

PubMed1992

Relationship between aerobic fitness level and daily energy expenditure in weight-stable humans.

The relationship between exercise and energy expenditure is unclear, with some suggestions that exercise leads to increased energy expenditure over and beyond the increase due to the exercise itself. In this cross-sectional study, we examined the relationships among aerobic fitness level, body composition, and total daily energy expenditure in 78 subjects. Daily energy expenditure (determined in a whole room calorimeter) was significantly correlated with both fat-free mass (FFM) and aerobic fitness (estimated from maximum aerobic capacity or VO2max). However, multiple-regression analysis demonstrated that, after accounting for FFM, VO2max did not explain a significant amount of the remaining variation in energy expenditure. In addition, the relationship between resting metabolic rate and both FFM and VO2max was evaluated using data from 214 weight-stable subjects analyzed retrospectively. The results were identical with the results obtained from the 78 subjects in that VO2max did not have effects independent of FFM on energy expenditure. We conclude that aerobic fitness does not have a direct effect on energy expenditure. However, it may have effects that are mediated through body composition, since in both populations studied here, VO2max was positively correlated with FFM and negatively correlated with adiposity.

Aerobiosis↗

PubMed1992

Human papillomavirus in women. A three-year experience in a county hospital colposcopy clinic.

The human papillomavirus (HPV) has been associated with cervical dysplasia and carcinoma. This report summarizes the authors' experience with HPV-related problems over three years, 1987-89, while managing 1,644 women at a county hospital colposcopy clinic. Probes for HPV DNA were not used, and the diagnoses were made with cytologic and histologic criteria alone. The percentage of patients referred to the clinic with HPV found on routine Papanicolaou smears rose significantly, from 3 in 1987 to 18 in 1989. Fifteen percent of those referred because of HPV on a Papanicolaou smear were found to have cervical intraepithelial neoplasia (CIN) grade II or III after they were evaluated at the clinic. Of the 367 cases of biopsy-proven cervical HPV, only 33 (9%) were recorded on Papanicolaou smears performed immediately before the biopsy, and 140 (38%) also had concomitant, biopsy-proven CIN, grade II or III. Of the 195 instances in which the colposcopic impression was simple HPV without CIN, 46 (24%) had high-grade CIN on biopsy. We conclude that the proportion of patients with HPV-associated problems is increasing, that the Papanicolaou smear is not sensitive in detecting cervical HPV infections, that patients with HPV changes found on Papanicolaou smears should be evaluated with colposcopy and that lesions that appear colposcopically to be simple HPV should undergo biopsy to rule out the presence of high-grade CIN.

Biopsy↗

PubMed1991

Nutrient balance in humans: effects of diet composition.

The purpose of this study was to examine the effect of alterations in diet composition on energy expenditure and nutrient balance in humans. Eight adults (three men, five women) ate a high-carbohydrate (60% of calories from carbohydrate) and a high-fat (60% of calories from fat) diet for 7 d each according to a randomized, crossover design. Six subjects were studied for an additional week on a mixed diet (45% of calories from fat). For each subject, total caloric intake was identical on all diets and was intended to provide the subject's maintenance energy requirements. All subjects spent days 3 and 7 of each week in a whole-room indirect calorimeter. Diet composition did not affect total daily energy expenditure but did affect daily nutrient oxidation by rapidly shifting substrate oxidation to more closely reflect the composition of the diet. These results show that diet composition can affect substrate oxidation without producing measurable effects on total energy expenditure.

Adult↗

PubMed1991

Comparison of nonionic and ionic contrast agents in the rabbit lung.

The objective of this study was to determine the short- and long-term radiographic, physiologic and histologic changes elicited in the lung of rabbits following the aspiration of commonly used radiographic contrast agents. All agents used, including nonionic agents, caused radiographically evident pulmonary edema which cleared by 24 hours. The contrast materials with higher osmolality, viscosity, and iodine content elicited the greatest physiologic and pathologic changes. No differences were found between an ionic and a nonionic agent with similar viscosities and iodine content, despite a lower osmolality in the nonionic agent. No contrast agent is innocuous when introduced into the lung.

Animals↗