Measuring leg muscle and fat mass in humans: comparison of CT and dual-energy X-ray absorptiometry

Dual-energy X-ray absorptiometry (DEXA) is reported to be inferior to computed tomography (CT) to measure changes in appendicular soft tissue composition. We compared CT- and DEXA-measured thigh muscle and fat mass to evaluate the random and systematic discrepancies between these two methods. Thigh skeletal muscle area (single-slice CT) was suboptimally (r(2) = 0.74, P < 0.0001) related to DEXA-measured thigh fat-free mass (FFM). In contrast, thigh muscle and adipose tissue volumes (multislice CT) were highly related to DEXA-measured thigh FFM and fat (both r(2) = 0.96, P < 0.0001). DEXA-measured leg fat was significantly less than multislice-CT-measured leg adipose tissue volume, whereas multislice-CT-measured leg muscle mass was less (P < 0.0001) than DEXA-measured leg FFM. The systematic discrepancies between the two approaches were consistent with the 10-15% nonfat components of adipose tissue. In conclusion, CT and DEXA measures of appendicular soft tissue are highly related. Systematic differences between DEXA and CT likely relate to the underlying principles of the techniques.

Clinical usefulness of MR imaging of the breast in the evaluation of the problematic mammogram

OBJECTIVE

This study was undertaken to determine the usefulness of MR imaging of the breast as an adjunct to mammography in problematic cases in which the significance, presence, or location of an abnormality could not be determined.

MATERIALS AND METHODS

From January 1993 through February 1998, 86 lesions for which histologic or mammographic follow-up was available were evaluated by breast MR imaging because of equivocal findings on mammography. MR studies were performed with a dedicated breast multicoil on a 1.5-T scanner. Early studies were done using a T1-weighted two-dimensional spin-echo sequence before and after the administration of contrast material. Later studies were performed using a three-dimensional fast spoiled gradient sequence with fat suppression. Studies were considered to be positive for an abnormality if a focal area of enhancement was seen after contrast administration.

RESULTS

MR imaging had positive findings in 38 sites. Twenty-six of these sites corresponded in location to the mammographic abnormality that had prompted the recommendation for MR imaging. The remaining 12 sites occurred in areas not suspected mammographically. At biopsy, 10 (26%) of the 38 positive sites were malignant. MR imaging had negative findings at 60 other sites that had been suspected mammographically. Of these 60 sites, six were treated with excision, all with benign results; the remaining 54 sites showed mammographic stability on follow-up that ranged from 5 to 66 months (mean, 19 months).

CONCLUSION

MR imaging of the breast can be a valuable adjunct to mammography for selected problematic cases.

Leptin responses to overfeeding: relationship with body fat and nonexercise activity thermogenesis

Administration of leptin to rodents results in weight loss through decreased food intake and increased energy expenditure that occurs in part through increased spontaneous activity. In humans, low levels of spontaneous physical activity and below normal plasma leptin concentrations predict subsequent excess weight gain. We recently found that failure to increase nonexercise activity thermogenesis (NEAT) with overfeeding results in greater fat gain in humans, and subsequently evaluated whether changes in leptin are related to NEAT activation. We measured plasma leptin concentrations and adipose tissue leptin messenger ribonucleic acid together with the components of energy expenditure in 16 nonobese humans before and after overfeeding to assess the relationship between leptin responses to overfeeding and the changes in NEAT. Adipocyte leptin expression was up-regulated with overfeeding, and leptin concentrations increased. Leptin concentrations correlated with body fat before and after overfeeding. Changes in leptin with overfeeding were strongly related to changes in body fat, but not to changes in NEAT. Changes in NEAT correlated inversely with fat gain. It is, therefore, unlikely that leptin mediates activation of NEAT with overfeeding in nonobese humans; rather, leptin directly reflects body fat mass and fat mass gain.

Preventing stroke in patients with atrial fibrillation

CONTEXT

Atrial fibrillation, a common disorder that affects nearly one sixth of the population aged 75 years and older, is a major risk factor for stroke.

OBJECTIVES

To review and evaluate the evidence supporting the use of warfarin and/or aspirin for stroke prevention in patients with atrial fibrillation.

DATA SOURCES

Prospective, randomized trials of patients with atrial fibrillation evaluating either warfarin or aspirin or both, from MEDLINE from January 1, 1966, to February 23, 1999.

STUDY SELECTION

Five primary prevention placebo-controlled studies, which had been formally pooled, 1 study evaluating secondary prevention of stroke, 1 study comparing warfarin with aspirin, and 3 studies of warfarin in combination with aspirin were identified.

DATA SYNTHESIS

The risk of developing stroke is heterogeneous and increases with each decade above 65 years; history of high blood pressure, diabetes mellitus, previous transient ischemic attack, or stroke; poor ventricular function; and in women older than 75 years. For patients younger than 65 years, without risk factors, and not receiving antithrombotic therapy, the risk of stroke is 1%/y; those without risk factors between the ages of 65 and 75 years have a risk of 1.1%/y if taking warfarin and 1.4%/y if taking aspirin. For all other patients, stroke risk is reduced from an untreated rate of between 4.3%/y and more than 12%/y to a rate of 1.2%/y to 4%/y with warfarin use.

CONCLUSION

The protection afforded by warfarin is most pronounced in patients at the highest risk for stroke, while aspirin treatment seems adequate in low-risk populations.

Role of nonexercise activity thermogenesis in resistance to fat gain in humans

Humans show considerable interindividual variation in susceptibility to weight gain in response to overeating. The physiological basis of this variation was investigated by measuring changes in energy storage and expenditure in 16 nonobese volunteers who were fed 1000 kilocalories per day in excess of weight-maintenance requirements for 8 weeks. Two-thirds of the increases in total daily energy expenditure was due to increased nonexercise activity thermogenesis (NEAT), which is associated with fidgeting, maintenance of posture, and other physical activities of daily life. Changes in NEAT accounted for the 10-fold differences in fat storage that occurred and directly predicted resistance to fat gain with overfeeding (correlation coefficient = 0.77, probability < 0.001). These results suggest that as humans overeat, activation of NEAT dissipates excess energy to preserve leanness and that failure to activate NEAT may result in ready fat gain.

Preservation of macronutrient preferences in cancer anorexia

Indirect evidence suggests that cancer anorexia is associated with specific aversions to macronutrients. To investigate this, patients with cancer anorexia and hospitalized control subjects devised 3-day menus comprising foods that they wished to eat. These foods were then provided for 3 days and the intakes of each food carefully measured. As expected, patients with cancer anorexia consumed substantially less energy than hospitalized control subjects (6.0 +/- 0.9 MJ vs 9.5 +/- 0.5 MJ, P < 0.001). However, macronutrient composition was consistently maintained in the patients with cancer anorexia. These data argue against cancer anorexia representing a state of macronutrient aversion.

Adenoviral-mediated gene transfer to human adipocytes in vitro, and human adipose tissue ex vivo and rabbit femoral adipose tissue in vivo

Adenoviral-mediated gene transfer has proven useful in several organ systems to understand gene action and to provide a potential therapeutic modality for localized, organ-specific gene overexpression. However, the application of adenoviral-mediated gene transfer to adipocytes and adipose tissue has not been evaluated. We evaluated the feasibility of in vitro and ex vivo transfer of the beta-galactosidase gene to human adipocytes and adipose tissue by means of adenoviral vectors. The efficiency (percentage of cells transduced) of adenoviral-mediated gene transfer of the beta-galactosidase gene to human adipocytes in vitro and to human adipose tissue ex vivo was 21 +/- 3% and 14 +/- 3%, respectively. Adenoviral-mediated gene transfer in a rabbit femoral adipose tissue was also demonstrated in vivo. Adenoviral-mediated gene transfer may facilitate studies on understanding the biology of adipocytes and provide a potential tool for the modulation of adipocyte function in vivo and thereby for the treatment of obesity.

Adipocyte macrophage colony-stimulating factor is a mediator of adipose tissue growth

Adipose tissue growth results from de novo adipocyte recruitment (hyperplasia) and increased size of preexisting adipocytes. Adipocyte hyperplasia accounts for the severalfold increase in adipose tissue mass that occurs throughout life, yet the mechanism of adipocyte hyperplasia is unknown. We studied the potential of macrophage colony-stimulating factor (MCSF) to mediate adipocyte hyperplasia because of the profound effects MCSF exerts on pluripotent cell recruitment and differentiation in other tissues. We found that MCSF mRNA and protein were expressed by human adipocytes and that adipocyte MCSF expression was upregulated in rapidly growing adipose tissue that encircled acutely inflamed bowel and in adipose tissue from humans gaining weight (4-7 kg) with overfeeding. Localized overexpression of adipocyte MCSF was then induced in rabbit subcutaneous adipose tissue in vivo using adenoviral-mediated gene transfer. Successful overexpression of MCSF was associated with 16-fold increases in adipose tissue growth compared with a control adenovirus expressing beta-galactosidase. This occurred in the absence of increased cell size and in the presence of increased nuclear staining for MIB-1, a marker of proliferation. We conclude that MCSF participates in adipocyte hyperplasia and the physiological regulation of adipose tissue growth.

Ureteral calculi in patients with flank pain: correlation of plain radiography with unenhanced helical CT

PURPOSE

To determine the sensitivity and specificity of plain radiography for the detection of ureteral calculi with use of unenhanced helical computed tomography (CT) as the standard of reference.

MATERIALS AND METHODS

Plain radiographs and helical CT scans of 178 patients with acute flank pain were reviewed retrospectively. Three interpretations of plain radiographs were used: (a) Original reading. This was the report made at the time of the patient's evaluation before the patient underwent CT. (b) Blinded retrospective reading. Each plain radiograph was interpreted without knowledge of the CT findings. (c) Unblinded retrospective reading. The plain radiograph of each patient whose CT scan showed a stone was reviewed with the CT scan.

RESULTS

The original reading had a sensitivity of 45% and a specificity of 77% for the detection of ureteral calculi. The blinded retrospective reading had a sensitivity of 59% and a specificity of 71%. The unblinded retrospective reading had a sensitivity of 59% (95% confidence interval: 47%, 70%).

CONCLUSION

Plain radiography is of limited value for aiding the diagnosis of ureteral stones. All patients with acute flank pain for whom radiologic imaging is recommended can directly undergo unenhanced helical CT; plain radiographs need not be obtained first.

Utility of a standardized sign-out card for new medical interns

Conscientious sign-out between medical interns is important for the continuity of care of hospitalized patients. We developed a standardized sign-out card that prompted the intern going off duty to transmit patient care information to the inter on call. The card was tested in a prospective, randomized, controlled trial in which one group of interns used the card, and another group did not. Any instance of poor sign-out was reported on a questionnaire completed by the intern who had been on call the previous night. The group using the sign-out cards reported poor sign-out on 8 nights (5.8% of questionnaires), and the control group reported it on 17 nights (14.9% of questionnaires, p = .016). The card was time-effective and inexpensive, resulted in more complete data recording, and possibly decreased the morbidity associated with poor sign-out.

Weighed dietary intakes in patients with chronic liver disease

Poor dietary intake is assumed to be a major causal factor in the malnutrition observed in patients with chronic liver disease. However, the dietary habits of this patient population are poorly documented. The aim of this study was to assess weighed dietary intakes in hospitalized patients with chronic liver disease. Twenty patients with liver disease (10 men, 10 women; mean +/- SD age, 46.2 +/- 10.9 yr, mean weight, 63.3 +/- 8.0 kg, mean body mass index, 22.1 +/- 2.8 kg/m2; 10 alcoholic, 10 nonalcoholic) and 20 general medical patients, matched for age and sex, underwent a 3-d weighed assessment of dietary intake. No significant differences were observed in food intake or dietary composition between the patients with liver disease and the hospital controls. Patients with alcoholic liver disease showed significant differences in dietary energy, protein, and carbohydrate intakes compared with the patients with nonalcoholic liver disease when data were expressed in absolute terms but not when expressed relative to body weight; dietary composition was similar in both groups. Overall, patients with chronic liver disease, especially those with alcohol-related injury, consume a diet comparable with that ingested by other hospital patients both in amount and composition.

Splinter hemorrhages following arterial puncture

Splinter hemorrhages can be a feature of the antiphospholipid syndrome. We describe a patient in whom splinter hemorrhages developed following radial artery puncture. The implications of this findings in patients with the antiphospholipid syndrome are discussed.

The use of a football helmet to secure a nasogastric tube

We describe the case of a 83-yr-old diabetic woman who, during convalescence for treatment of hyperosmolar nonketotic diabetic coma, required nasogastric intubation for enteral feeding. Her course was complicated by delirium during which time she repeatedly removed the nasogastric tube. A football helmet was used to secure the feeding tube and prevent its premature removal. Thereafter nasogastric feeding was uncomplicated. We recommend the use of a football helmet in patients with delirium who repeatedly remove their nasogastric tubes.

Brunner's gland hamartomas: clinical presentation and pathological features of 27 cases

OBJECTIVES

The aim of this study was to characterize the clinical presentation, pathological features, and outcome of a series of patients with Brunner's gland hamartomas.

METHODS

We reviewed the clinical and pathological features of 27 patients who presented with Brunner's gland hamartomas, and we obtained follow-up information.

RESULTS

Patients (12 men and 15 women) presented predominantly in the fifth and sixth decades of life either with gastrointestinal hemorrhage (n = 10) or obstructive symptoms (n = 10); there were also patients whose tumors were discovered as an incidental finding (n = 7). The tumors were generally pedunculated, were located in the first portion of the duodenum, and were in the range of diameter from 1 to 6 cm. Histologically, the hamartomas were characterized by the presence of nondysplastic, lobulated Brunner's glands with intervening bands of fibrous tissue and variable adipose and lymphoid tissue. Focal sclerosis was found in 93% of the hamartomas, possibly mimicking an adenocarcinoma. Whether managed surgically (24 patients) or endoscopically (three patients), the outcome was uniformly favorable. After a median period of 7-yr-follow-up, no tumors recurred, and no additional morbidity was identified.

CONCLUSIONS

Brunner's gland hamartomas are rare duodenal tumors occurring in middle age that present either with gastrointestinal hemorrhage, obstructive symptoms, or as an incidental finding. Surgical or endoscopic excision is uncomplicated, and the long-term outcome is favorable.

New nonionic triiodinated x-ray contrast media containing the N-(2-hydroxyethyl)aminopropane-2,3-diol side chain

We have found the amino alcohol (HE)APD to be an effective solubilizing and detoxifying agent for triiodinated benzene XRCM. Most of the compounds containing the (HE)APD moiety displayed good solution properties (low osmolality and viscosity) and relatively low toxicities. A general trend was observed in which compounds with low hydrophilicity were more toxic. High hydrophilicity was found to be necessary for low intracisternal toxicity, but is not the only criterion. Use of the 5-glycolamido group provides compounds with high hydrophilicity. When all the properties were compared, the best compounds in this study were found to be the three asymmetrically substituted isophthalamides containing the (HE)APD and APD side chains (4a-c: MP-1556, MP-1683, and MP-1689). These compounds have excellent solution properties (low osmolality and viscosity) and low intravenous and intracisternal toxicities, and compare favorably to current clinical agents.

Are Patients in Favour of General Health Screening?

In order to determine whether patients are in favour of general health screening, two sex-matched groups of patients of similar age from a general practice were studied; a group of 315 consecutive patients who attended the practice and 93 individuals who had not attended the practice for at least 12 months were studied. Individuals in both groups were provided with a short, anonymous questionnaire about their desire for general health screening. Although roughly equal proportions of the attenders (93%) and non-attenders (88%) indicated that general health screening was a ‘good idea’, a significantly greater proportion of the attenders (83%) indicated that they would make an appointment and attend the practice for health screening compared to the non-attenders (66%) (P < 0.002). Similarly, a significantly greater proportion of the attenders (33%) indicated that they would seek general health screening, even if not contacted by their doctor, when compared with the non-attenders (16%) (P < 0.001). Thus patients in this study were greatly in favour of general health screening. However, patients who attended the general practice infrequently may represent a population who are relatively resistant to health screening.

Synthesis and structure-activity studies of alkyl-substituted gamma-butyrolactones and gamma-thiobutyrolactones: ligands for the picrotoxin receptor

A series of gamma-butyrolactones and gamma-thiobutyrolactones possessing a variety of alkyl groups and alkyl-substitution patterns was prepared and evaluated for anticonvulsant and convulsant activity. Behavioral studies performed on these compounds suggest that maximal anticonvulsant activity (against maximal electroshock and pentylenetetrazol) results when three or four carbon atoms are present at the alpha-position. For convulsant potency, a similar dependence on the size of the alkyl chain at the beta-position was observed. Additional gamma-dimethyl groups were found to increase the convulsant potency of a beta-substituted compound and to cause an alpha-substituted anticonvulsant to become a convulsant. In general, sulfur for oxygen heteroatom substitution in the alpha-substituted lactones resulted in improved anticonvulsant potency and spectrum of activity. Binding of these compounds to the picrotoxin site of the GABA receptor complex was demonstrated with a [35S]-tert-butylbicyclophosphorothionate radioligand binding assay. Measurements of brain concentrations for selected compounds supports a hypothesis that correlates binding to the picrotoxin site with the pharmacological effects of these compounds.

The children of teenage mothers: patterns of early childbearing in two generations

Twenty years after a mostly black group of Baltimore women became adolescent mothers, the majority of their first-born children had not become adolescent parents, a finding that challenges the popular belief that the offspring of teenage mothers are themselves destined to become adolescent parents. Almost all of the offspring had had intercourse by age 19. About half of the young women had experienced a pregnancy before that age, and approximately one-third of the young men reported having impregnated a partner before age 19. The Baltimore youths were just as likely to have had a live birth before age 19 as were the children of teenage mothers in a national sample of urban blacks, and both of these groups were more likely to have done so than were the children of older mothers in the national sample. In the Baltimore sample, maternal welfare experience only increased a daughter's likelihood of early childbearing if welfare was received during her teenage years. Within the Baltimore sample, a direct comparison of the daughters who became adolescent mothers with their own mothers at a comparable age reveals that the daughters have bleaker educational and financial prospects than their mothers had, and are less likely to ever have married. These results suggest that today's teenage parents may be less likely than were previous cohorts of adolescent mothers to overcome the handicaps of early childbearing. This trend could portend the growth of an urban underclass, even though only a minority of the offspring of teenage mothers go on to become adolescent parents.

Validation of a computer based system for assessing dietary intake

Dietary intake was assessed in 50 patients in hospital by using a dietary history method and computer based system for data collection and standard food tables to calculate the composition of nutrients. The results were compared with those from a weighed assessment that was calculated by using both food tables and manufacturers' food analyses. The use of the food tables overestimated mean (SEM) individual nutrient intakes by between 2.5% (1.5%) and 15.5% (3.0%). The mean errors associated with the dietary history assessment varied from -23% (7.8%) for fat intake to +21.4% (8.5%) for carbohydrate intake. Overall, 30% of the assessments of total nutrient intakes that were calculated using this method were within -20% to +20% of actual values; 18% were within -10% to +10%. The mean errors associated with the computer based assessment varied from -1.0% (4.3%) for carbohydrate intake to +8.5% (3.4%) for protein intake. Overall, 56% of the assessments of total nutrient intakes were within -20% to +20% of actual intakes; 31% were within -10% to +10%. The computer based system provides an accurate, reproducible, convenient, and inexpensive method for assessing dietary intake.

The significance of learned food aversions in the aetiology of anorexia associated with cancer

The results of 24 h food preference tests have suggested that learned food aversions may be involved in the development of anorexia in tumour bearing rats and in patients with cancer. We have performed similar tests over longer periods, up to 10 days, in male rats implanted with Leydig cell tumours, using semisynthetic diets containing differing proportions of fat, protein and carbohydrate. Tumour growth caused anorexia (16-30% decrease in food intake) and cachexia (78% decrease in body fat and 18% decrease in body protein, but 16% increase in body water). Both tumour bearing and control rats preferred a high carbohydrate diet to a high fat diet regardless of their previous diet: tumour bearing rats showed no evidence of a learned food aversion in these experiments. Tumour bearing rats did show an initial preference for a novel high protein diet when this was offered as an alternative to the normal protein diet they had previously been consuming, but this apparent learned food aversion disappeared on the second day of the test and was in fact reversed on all the subsequent days of the test. However, tumour bearing rats did show a sustained preference for a novel low protein diet when this was offered as an alternative to the normal protein diet they had previously been consuming. These results suggest that anorexia in the tumour bearing rats was not caused by a learned food aversion. However the results do indicate that the tumour bearing rats may have developed a specific aversion to protein in the diet. Leydig cell tumours are known to secrete large amounts of oestradiol. However injections of oestradiol in normal male rats caused an increase in body fat content and had no effect on the rats' preference for dietary protein. Clearly hypersecretion of oestradiol was not responsible for the loss of body fat, the fluid retention and the aversion to dietary protein which characterised the tumour bearing rats. The mechanisms by which tumour growth causes anorexia and cachexia in these rats remains obscure.