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Biomedical subjects

K Mulligan

Publications and source records attributed to K Mulligan.

At least 37 records · Page 2Linked to original sources
PubMed1998

"Buffalo hump" in men with HIV-1 infection.

BACKGROUND: Enlargement of the dorsocervical fat pad ("buffalo hump") has been reported in numerous HIV-1-infected patients. Some investigators have speculated that this finding is associated with protease-inhibitor treatment. METHODS: Between June, 1995, and October, 1997, we studied eight HIV-1-infected men who had developed a buffalo hump while otherwise stable on antiretroviral therapy. Measurement of 24 h urinary free cortisol excretion and an overnight low-dose dexamethasone suppression test were done to screen for Cushing's syndrome. In one patient, plasma cortisol concentrations were measured every 4 h for 24 h to assess the circadian rhythm of cortisol. Results of total and regional body-composition analysis by dual-energy X-ray absorptiometry, and glucose, cholesterol, triglyceride, and cortisol concentrations were compared with those obtained in a control population of 15 HIV-1-positive men whose age, body-mass index (BMI), and CD4-lymphocyte count were within the range of values in the eight study patients. FINDINGS: The eight patients with a buffalo hump were clinically stable on various antiretroviral regimens, four of which included a protease inhibitor. No other signs of Cushing's syndrome were observed, and plasma cortisol values did not differ significantly from those of controls. 24 h urinary free cortisol excretion was normal in seven patients and slightly raised in one (248 nmoles). In this patient, a repeat 24 h urinary free cortisol was 175 nmoles and plasma cortisol concentrations over 24 h showed a normal circadian pattern (nadir 83 nmol/L at 2400 h). All eight patients had normal suppression of cortisol values after dexamethasone 1 mg (plasma cortisol less than 83 nmol/L). When compared with HIV-1-positive controls, men with a buffalo hump had a significantly greater proportion of fat in the trunk region, suggesting central fat accumulation. Triglyceride but not cholesterol values were higher in the patients than in controls but this difference was not significant. Fasting glucose values did not differ significantly. INTERPRETATION: The development of a buffalo hump cannot be attributed to hypercortisolism in these eight men. Furthermore, its occurrence is not unique to patients on protease inhibitors. Although the mechanism for dorsocervical fat accumulation is unclear, we speculate that regional abnormalities in lipogenesis and lipolysis occur, possibly influenced by the hormonal and metabolic changes seen with HIV-1 infection and its treatment.

Adipose Tissue↗
PubMed1998

Patients report positive nutrition counseling outcomes.

OBJECTIVE: Assess outcomes of patient nutrition counseling. DESIGN: A descriptive study based on the results of a telephone interview performed 2 to 8 weeks after counseling. SUBJECTS/SETTING: Subjects were 400 adult patients referred for nutrition counseling at 2 academic health centers. Of these, 274 patients received nutrition counseling during hospitalization and 126 as outpatients. STATISTICAL ANALYSIS: Descriptive statistics were used to summarize data and the Mann-Whitney U statistic and logistic regressions were used to test significant differences (P < .05) between inpatient and outpatient counseling outcomes. RESULTS: Most patients (83%) gave a partial or full description of their diet modifications and 79% had a moderate or good understanding of their diet. Most patients reported that the dietitian's advice was suited to their special needs (88%) and that they knew what to eat (83%). A majority (62%) had made dietary changes, but 17% said they had had trouble changing their diets as suggested. After talking with a dietitian, 57% felt better emotionally, 37% felt better physically, 64% felt in control of their condition, and 43% noticed improved health indicators. Initial analysis indicated that outpatients reported better outcomes than inpatients; further analysis showed that these differences could be attributed to younger ages among the outpatient sample. APPLICATIONS/CONCLUSIONS: Patient nutrition counseling has positive outcomes. Therefore, key counseling points should be introduced or reinforced in inpatient settings, in conjunction with multiple-session protocols during the pre- and/or posthospitalization continuum of care. Dietitians, managers, administrators, and credentialing agencies should work together to secure and promote the necessary physical, personnel, and financial resources to make this happen.

Adult↗
PubMed1998

Effects of chronic growth hormone treatment on energy intake and resting energy metabolism in patients with human immunodeficiency virus-associated wasting--a clinical research center study.

In previous studies, treatment with recombinant human GH (rhGH) produced sustained increases in weight and lean body mass (LBM) and decreases in fat mass in patients with human immunodeficiency virus (HIV)-associated wasting. To evaluate the effects of chronic rhGH treatment on components of energy balance, we recruited separate subgroups of HIV-positive patients with an involuntary weight loss of 10% or more to undergo paired measurements of resting energy metabolism (n = 6) or food intake (n = 11) before and during the final week of a 3-month rhGH (0.1 mg/kg.day) treatment period. In the energy metabolism subset, resting energy expenditure (REE) and substrate oxidation rates were measured by indirect calorimetry during brief admissions to a metabolic ward. Patients in the energy intake subset prepared written 4-day food intake diaries. Body composition was measured in both groups by bioelectrical impedance analysis. Changes in weight (+2.2 +/- 0.9 and +2.2 +/- 0.6 kg), LBM (+3.2 +/- 0.6 and +3.8 +/- 0.5 kg), and fat (-1.0 +/- 0.5 and -1.6 +/- 0.5 kg) in the energy metabolism and energy intake subsets, respectively, did not differ between groups and were comparable to changes seen in a larger group of patients who received rhGH in a randomized, double blind, placebo-controlled multicenter study. In the energy metabolism subset, REE (+232 +/- 69 Cal/day; P = 0.020) and lipid oxidation (+3.1 +/- 1.0 Cal/kg LBM.day; P = 0.016) increased, whereas protein oxidation decreased (-1.3 +/- 1.0 Cal/kg LBM.day; P = 0.027) during rhGH therapy. These changes in REE and substrate oxidation are comparable to changes we noted previously in a study of the effects of short term rhGH treatment in patients with HIV-associated wasting. Moreover, the sustained increases in lipid oxidation are consistent with the decreases in body fat content that occur with rhGH treatment. In the energy intake subset, a trend for increased daily energy intake (+203 +/- 262 Cal; P = 0.456) is obviated when adjustments for changes in weight or LBM are made (+1.3 +/- 4.0 and -0.5 +/- 5.0 Cal/kg BW and LBM, respectively). Taken together, these results demonstrate that increases in weight and LBM that occur with chronic rhGH therapy are accompanied by sustained increases in REE and lipid oxidation and decreases in protein oxidation. These changes in body composition occur without a significant increase in energy intake and may, instead, represent a redistribution of body energy stores.

Adult↗
PubMed1998

Leptin, body composition, and indices of malnutrition in patients on dialysis.

A cross-sectional study was performed in a group of dialysis patients and control subjects to identify the determinants of serum levels of leptin, the protein product of the obese (ob) gene. Twenty-eight patients on dialysis (19 patients on hemodialysis [HD] and nine patients on peritoneal dialysis [PD]) and 41 healthy control subjects were studied. For each subject, blood was drawn for measurement of serum leptin levels and body composition was analyzed by dual-energy x-ray absorptiometry. Regression analyses were performed to determine the predictors of leptin levels, the independent contribution of HD and PD, and the relationship between leptin levels and markers of malnutrition and protein intake in the patients on dialysis. As expected, percentage of body fat was strongly correlated with leptin levels in the group as a whole and in each subgroup when analyzed separately. However, the slope of the relationship was significantly greater for dialysis patients than for control subjects (P < 0.05). Multivariate regression analysis showed that patients on HD and PD had higher leptin levels than control subjects even after adjustment for age, gender, and percentage of body fat. Univariate analyses were performed to assess the relationship between leptin levels and markers of nutritional status such as albumin, blood urea nitrogen, protein catabolic rate (PCR), transferrin, cholesterol, and lean body mass per height. There was a significant negative correlation between leptin levels and serum albumin (r = -0.598, P < 0.001) and between leptin and PCR (r = -0.433, P < 0.05) in the patients on dialysis. It is concluded that leptin levels adjusted for percentage of body fat are increased in dialysis patients compared with control subjects, particularly in those on PD. In addition, increased leptin levels are associated with low serum albumin levels and PCR in dialysis patients.

Adult↗
PubMed1998

Energy expenditure and protein metabolism in human immunodeficiency virus infection and cancer cachexia.

Malnutrition and weight loss are clinically significant complications of both human immunodeficiency virus (HIV) infection and cancer. Over the last two decades, multiple abnormalities in energy and protein metabolism have been documented in patients with cancer and, more recently, in HIV infection. In HIV infection, studies of the components of energy balance have demonstrated that weight loss results primarily from decreased energy intake, coupled with a failure to consistently reduce resting energy expenditure. Although several studies have shown that resting energy expenditure is elevated in many patients with HIV infection, other studies have shown that not all patients with HIV infection are hypermetabolic. Likewise, protein turnover is increased, decreased, or unchanged in patients with HIV infection and varies with the physiologic state of the patient. In cancer patients, studies of resting energy expenditure have produced similarly varying results, depending in part on tumor type and dietary intake. Protein turnover studies in patients with cancer suggest that support of the tumor may occur at the expense of host skeletal muscle. Abnormalities of glucose and lipid metabolism have been noted as well. Thus, pharmacologic intervention may be needed to restore weight and lean tissue in patients with weight loss associated with either HIV infection or cancer.

Cachexia↗
PubMed1998

Clinical trials update in human immunodeficiency virus wasting.

The major acquired immunodeficiency syndrome (AIDS) clinical trials groups in the Division of AIDS of the National Institutes of Health have been investigating weight loss and wasting in persons with the human immunodeficiency virus (HIV) and AIDS. Both the AIDS Clinical Trials Group (ACTG) and the Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA) have developed research projects to study the pathogenesis, diagnosis, prevention, and treatment of HIV-related malnutrition and wasting. This article reviews multicenter trials concerning HIV-related malnutrition and wasting conducted by the AIDS clinical trials groups. CPCRA trials will examine the effects of caloric supplements and triglycerides, or the use of megestrol acetate, oxandrolone, and progressive resistance training, on weight loss in patients with HIV-associated wasting. Planned ACTG trials will study the effects of the combination of megestrol acetate and testosterone, the testosterone derivative nandrolone decanoate, or highly active antiretroviral therapy on weight loss. Results from these studies may also have relevance to clinical oncologists who are treating patients with cancer-related cachexia.

Anabolic Agents↗
PubMed1997

Cross-sectional and longitudinal evaluation of body composition in men with HIV infection.

Body wasting is an increasingly prevalent AIDS-defining condition and an independent risk factor for mortality in patients infected with HIV. Largely on the basis of studies conducted early in the epidemic, HIV-associated wasting has been assumed to feature a disproportionate loss of lean tissue. We report the results obtained from cross-sectional and longitudinal studies that differ from these earlier observations. In a cross-sectional analysis, weight and body composition determined by dual-energy x-ray absorptiometry and bioelectrical impedance analysis in 32 HIV-infected men with documented weight loss of > or = 10% were compared to those in 46 HIV-positive men without significant weight loss and 32 HIV-negative controls. Fat, lean body mass (LBM), and body cell mass (BCM) were significantly lower in men with weight loss relative to controls (p < 0.001 for fat and BCM; p = 0.01 for LBM). Two thirds of the difference in weight was fat. For the longitudinal analysis, the composition of weight lost over time was evaluated in paired measurements in men grouped by body fat content (<15% or >15%, n = 10 per group). Weight loss in patients with baseline fat of more than 15% was only 16% LBM, but the composition of weight lost in men with baseline fat of less than 15% was 70% LBM. We conclude that progressive decreases in fat and lean tissue occur in men with HIV infection, with the composition of weight lost depending on baseline fat content. These results argue against the widely held notion that HIV-associated wasting is characterized by preservation of fat at the expense of lean tissue.

Adipose Tissue↗
PubMed1997

Simulated optic flow and extrastriate cortex. I. Optic flow versus texture.

A locomoting observer sees a very different visual scene than an observer at rest: images throughout the visual field accelerate and expand, and they follow approximately radial outward paths from a single origin. This so-called optic flow field is presumably used for visual guidance, and it has been suggested that particular areas of visual cortex are specialized for the analysis of optic flow. In the cat, the lateral suprasylvian visual area (LS) is a likely candidate. To test the hypothesis that LS is specialized for analysis of optic flow fields, we recorded cell responses to optic flow displays. Stimulus movies simulated the experience of a cat trotting slowly across an endless plain covered with small balls. In different simulations we varied the size of balls, their organization (randomly or regularly dispersed), and their color (all one gray level, or multiple shades of gray). For each optic flow movie, a "texture" movie composed of the same elements but lacking optic flow cues was tested. In anesthetized cats, > 500 neurons in LS were studied with a variety of movies. Most (70%) of 454 visually responsive cells responded to optic flow movies. Visually responsive cells generally preferred optic flow to texture movies (69% of those responsive to any movie). The direction in which a movie was shown (forward or reverse) was also an important factor. Most cells (68%) strongly preferred forward motion, which corresponded to visual experience during locomotion.

Animals↗
PubMed1997

Simulated optic flow and extrastriate cortex. II. Responses to bar versus large-field stimuli.

In the preceding paper we described the responses of cells in the cat's lateral suprasylvian visual area (LS) to large-field optic flow and texture movies. To assess response properties such as direction selectivity, cells were also tested with moving bar stimuli. We expected that there would be good agreement between response properties elicited with optic flow movies and those revealed with bar stimuli. We first asked how well bar response properties predicted responsiveness to optic flow movies. There was no correlation between responsiveness to movies and the degree of end-stopping, length summation, or preference for bars that accelerated and expanded. We then considered only the 322 cells that responded to both bars and optic flow or texture movies and asked how well the strength of their response to movies could be predicted from the direction-tuning curves generated with bar stimuli. One-third of these cells responded much more strongly to movies than could be predicted from their direction-tuning curves. Generally, such cells were rather well tuned for the direction of bar motion and preferred a direction substantially different from what they saw in optic flow movies. Optic flow movies shown in the forward direction were the most effective variety of movie for two-thirds of these cells. To see whether this outcome stemmed from differential direction tuning for bars and large multielement displays, in a second series of experiments we compared direction tuning for bars and large-field texture movies. Many cells showed substantially different direction tuning for the two kinds of stimulus: almost 1/3 of 409 cells had tuning curves that overlapped each other by < 50%. But only a small number of cells (< 10%) responded much better to texture movies than to bars in the predominant direction of image motion in optic flow movies. This result, like that reported in the preceding paper, suggests that cells in LS respond differently to optic flow than to texture displays lacking optic flow motion cues.

Animals↗
PubMed1996

Recombinant human growth hormone in patients with HIV-associated wasting. A randomized, placebo-controlled trial. Serostim Study Group.

BACKGROUND: Body wasting, particularly loss of body cell mass, is an increasingly prevalent acquired immunodeficiency syndrome (AIDS)-defining condition and is an independent risk factor for death in patients infected with the human immunodeficiency virus (HIV). Treatment with growth hormone for 7 days resulted in weight gain and nitrogen retention, but the long-term effects of this treatment in patients with HIV-associated wasting are not known. OBJECTIVE: To evaluate the long-term effect of treatment with growth hormone on weight, body composition, functional performance, and quality of life in patients with HIV-associated wasting. DESIGN: Randomized, double-blind, placebo-controlled, multicenter trial. SETTING: Outpatient university and community-based patient care facilities. PATIENTS: 178 HIV-infected patients with documented unintentional weight loss of at least 10% or weight less than 90% of the lower limit of ideal body weight. INTERVENTION: Patients were randomly assigned to receive either recombinant human growth hormone, 0.1 mg/kg of body weight per day (average dosage, 6 mg/d) (n = 90) or placebo (n = 88) for 12 weeks. MEASUREMENTS: Weight; body fat, lean body mass, and bone mineral content (measured by dual-energy x-ray absorptiometry); total body water (by deuterium oxide dilution); extracellular water (by sodium bromide dilution); work output (by treadmill exercise); quality of life; and safety of treatment. RESULTS: Treatment with growth hormone resulted in a sustained and statistically significant increase in weight (mean increase +/- SD, 1.6 +/- 3.7 kg [P < 0.001]) and lean body mass (3.0 +/- 3.0 kg [P < 0.001]), accompanied by a decrease in body fat (-1.7 +/- 1.7 kg [P < 0.001]). In contrast, in patients receiving placebo, weight (increase, 0.1 +/- 3.1 kg), lean body mass (decrease, 0.1 +/- 2.0 kg), and body fat (decrease, 0.3 +/- 2.2 kg) did not change significantly from baseline. Differences between groups at week 12 were statistically significant (P = 0.011 for body weight and P < 0.001 for lean body mass and body fat). A greater increase in treadmill work output was noted in the group receiving growth hormone (increase, 99 +/- 293 kg. m/min) compared with the group receiving placebo (increase, 20 +/- 233 kg.m/min)(P = 0.039). Health status (quality of life) scores did not differ between groups at baseline or after treatment. Days of disability and use of medical resources were the same for both groups. Treatment was was well tolerated; no significant differences were seen between groups in clinical events, progression of AIDS, CD4+ or CD8+ cell counts, or viral burden. CONCLUSION: Treatment with growth hormone increases body weight, lean body mass, and treadmill work output and appears to be a safe and potentially effective therapy in patients with HIV-associated wasting.

Adult↗
PubMed1995

Improving active compression-decompression cardiopulmonary resuscitation with an inspiratory impedance valve.

BACKGROUND: Active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) has recently been demonstrated to provide significantly more blood flow to vital organs during cardiac arrest. To further enhance the effectiveness of this technique, we tested the hypothesis that intermittent impedance to inspiratory gas exchange during the decompression phase of ACD CPR enhances vital organ blood flow. METHODS AND RESULTS: ACD CPR was performed with a pneumatically driven automated compression-decompression device in a porcine model of ventricular fibrillation (VF). Nine pigs were randomized to receive ACD CPR alone, while 8 pigs received ACD CPR plus intermittent impedance to inspiratory gas exchange with a threshold valve set to 40 cm H2O. Results comparing 2 minutes of ACD CPR alone versus ACD CPR with the inspiratory impedance threshold valve (ITV) revealed significantly higher mean (+/- SEM) coronary perfusion pressures (diastolic aortic minus diastolic right atrial pressures) in the ITV (31.0 +/- 2.3 mm Hg) group versus with ACD CPR alone (21 +/- 3.6 mm Hg) (P < .05). Total left ventricular and cerebral blood flows, determined by radiolabeled microspheres, were 0.77 +/- 0.095 and 0.47 +/- 0.06 mL/min per gram, respectively, with ACD CPR plus the ITV versus 0.45 +/- 0.1 and 0.32 +/- 0.016 mL/min per gram, respectively, with ACD CPR alone (P < .05). Similar improvements in the ITV group were observed after 7 minutes of ACD CPR. After 16 minutes of VF and 13 minutes of ACD CPR, 6 of 8 pigs in the ITV group were successfully resuscitated with less than three successive 150-J shocks, whereas only 2 of 9 pigs with ACD CPR alone were resuscitated with equivalent energy levels (P < .02). With up to three additional and successive 200-J shocks, all pigs in the ITV group and 7 of 9 pigs with ACD CPR alone were resuscitated (P = .18). CONCLUSIONS: Intermittent impedance to inspiratory flow of respiratory gases during ACD CPR significantly improves coronary perfusion pressures and vital organ blood flow and lowers defibrillation energy requirements in a porcine model of VF.

Animals↗
PubMed1993

A comparison of magnification functions in area 19 and the lateral suprasylvian visual area in the cat.

A retinotopic map can be described by a magnification function that relates magnification factor to visual field eccentricity. Magnification factor for primary visual cortex (V1) in both the cat and the macaque monkey is directly proportional to retinal ganglion cell density. However, among those extrastriate areas for which a magnification function has been described, this is often not the case. Deviations from the pattern established in V1 are of considerable interest because they may provide insight into an extrastriate area's role in visual processing. The present study explored the magnification function for the lateral suprasylvian area (LS) in the cat. Because of its complex retinotopic organization, magnification was calculated indirectly using the known magnification function for area 19. Small tracer injections were made in area 17, and the extent of anterograde label in LS and in area 19 was measured. Using the ratio of cortical area labeled in LS to that in area 19, and the known magnification factor for area 19 at the corresponding retinotopic location, we were able to calculate magnification factor for LS. We found that the magnification function for LS differed substantially from that for area 19: central visual field was expanded, and peripheral field compressed in LS compared with area 19. Additionally, we found that the lower vertical meridian's representation was compressed relative to that of the horizontal meridian. We also examined receptive field size in areas 17, 19, and LS and found that, for all three areas, receptive field size was inversely proportional to magnification factor.

Animals↗
PubMed1993

An evaluation of the efficacy and safety of tetrahydroaminoacridine (THA) without lecithin in the treatment of Alzheimer's disease.

Seventy-nine patients with probable Alzheimer's disease were enrolled into a double-blind, placebo-controlled cross-over study to assess the therapeutic effect and safety of THA (tetrahydroaminoacridine; tacrine) without concomitant lecithin administration. Forty-one patients completed the trial which consisted of two 12-week treatment phases separated by a 4-week wash-out period. Twenty-six subjects were withdrawn during the active treatment phase, mostly because of elevated transaminases or cholinergic side-effects, and ten during treatment with placebo. Statistical analyses were conducted on two groups of patients; those completing the cross-over and those with at least one evaluation in the first treatment period. This latter analysis, using the last observation carried forward was used to approximate an intention-to-treat analysis. THA was favoured over placebo in all three primary outcome measures (MMSE, ADAS Non-cognitive Scale, and the Functional Life Scale), but the results did not reach statistical significance. THA was favoured over placebo in five of the seven secondary outcome measures, but for only two of these was statistical significance attained. In terms of a three-point or greater increase in MMSE score, three to four times as many subjects improved on THA as on placebo.

Activities of Daily Living↗
PubMed1993

The effect of exercise on fructose absorption.

The effect of exercise on intestinal absorption of fructose was evaluated in 10 subjects after they consumed four beverages, each containing a total of 50 g carbohydrate: 100% fructose (100F), 95% fructose and 5% glucose (95F), 70% fructose and 30% glucose (70F), and 100% glucose (100G), as well as a water placebo. With 100F and 95F, breath hydrogen, which is an index of incomplete absorption, increased significantly in all subjects. In contrast, hydrogen excretion did not increase in any subject after consumption of 100G or water, or in five of seven subjects who consumed 70F. The rapid increase in hydrogen excretion observed when consumption of 100F was followed by exercise was not noted during a comparable nonexercise trial. These data suggest that intestinal capacity for absorption of fructose is readily saturated after ingestion of amounts as small as 50 g and that exercise, which reduces intestinal transit time, can cause incomplete absorption of fructose.

Fructose↗
PubMed1993

Anabolic effects of recombinant human growth hormone in patients with wasting associated with human immunodeficiency virus infection.

Body wasting, characterized by disproportionate loss of body cell mass, is a feature of many chronic diseases, including infection with the human immunodeficiency virus (HIV). Therapies that merely increase energy intake do not consistently restore body cell mass in patients with the wasting syndrome. Because treatment with GH has induced nitrogen (N) retention in catabolic patients after surgery, burns, cancer, and hypocaloric feeding, we designed this study to determine whether GH could also produce an anabolic response in persons with HIV-associated weight loss. Six HIV-positive (HIV+) men with an average weight loss of 19% and six healthy weight-stable controls (HIV-) were hospitalized on a metabolic ward, where they consumed a constant metabolic diet during successive 5-day precontrol, 7-day baseline, and 7-day treatment [recombinant human GH (rhGH), 0.1 mg/kg.day] periods. The effects of rhGH on body weight, N and electrolyte excretion, energy expenditure, substrate oxidation, and integrated lipid and carbohydrate metabolism were assessed. Body weight increased promptly and progressively during treatment (2.0 +/- 0.3 and 1.6 +/- 0.2 kg in HIV+ and HIV-, respectively). Urinary N excretion decreased by 288 +/- 17 and 287 +/- 42 mmol/day in HIV+ and HIV-, respectively. Resting energy expenditure increased by 7.5% in both groups. Protein oxidation decreased, whereas lipid oxidation increased significantly. Glucose flux increased, and modest increases in fasting plasma triglyceride, glucose, and insulin levels were observed. Thus, short term rhGH treatment increased both protein anabolism and protein-sparing lipid oxidation, effects that should increase body cell mass if sustained during chronic therapy.

Adult↗