Defibrillation and the geometry of the heart: a novel measurement with implications for defibrillation mechanisms

We present a novel measurement for studying defibrillation mechanisms: the time course of changes in the size of the left ventricular (LV) cavity within 500 ms following defibrillation. Mechanical changes can be linked to electrical mechanisms via an understanding of excitation-contraction coupling. Eight mongrel dogs were internally defibrillated 5-50 seconds (including backup shocks) after the onset of 20 ventricular fibrillation (VF) episodes per animal. Two dimensional, short axis, LV cavity, ultrasound images were recorded at 30 frames per second just prior to inducing VF, during defibrillation and following the shock. Each frame was individually analysed to yield the LV cavity area as a function of time. Defibrillation shocks were followed by a highly reproducible phenomenon: (1) a dramatic and rapid increase in LV area, (2) a more or less prominent LV area plateau and (3) a decrease in the LV area. The peak fractional area increase ranged from 1.65 to 4.64 times larger than the baseline (LV area just prior to defibrillation), averaging 2.18 +/- 0.686. Successful shocks took significantly longer (p < 0.01) to return to 1.3 times the baseline (407 +/- 209 ms) than unsuccessful shocks (296 +/- 130 ms). Extrapolating to electrical mechanisms, our novel measurement demonstrates that defibrillation causes immediate relaxation and therefore suggests a significant role for deexcitation in defibrillation.

Peripheral administration of human corticotropin-releasing hormone: a novel method to increase energy expenditure and fat oxidation in man

CRH increases energy expenditure and decreases food intake in experimental animals. We proposed the hypothesis that peripheral administration of CRH might increase energy expenditure in human subjects. Four men and four women (age, 19-39 yr) were randomized to a double blind, cross-over trial to test the effect of human CRH (hCRH), ovine CRH (oCRH), and placebo on resting energy expenditure measured by indirect calorimetry. CRH was administered by primed continuous infusion at progressively increasing doses of 0.5, 1.0, and 2.0 microg/kg.h at 2-h intervals. hCRH increased resting energy expenditure by 13.9% at the end of the infusion. Respiratory quotient fell from 0.828 to 0.768 during the hCRH infusion compared with a fall from 0.836 to 0.807 during placebo infusion (P < 0.05). Fat oxidation increased by 55% compared with placebo at the highest dose of hCRH. Heart rate increased during hCRH to 10.7 bpm higher than placebo (P < 0.05). oCRH did not increase heart rate. oCRH also had no significant effect on respiratory quotient, and only a small effect on energy expenditure. During hCRH infusion, venous plasma epinephrine, norepinephrine, glycerol, and nonesterified fatty acid levels were not significantly different from those during placebo treatment. Peripheral CRH administration offers a novel strategy to increase energy expenditure.

Viral infections after renal transplantation

Viral infections are a leading cause of posttransplantation morbidity and mortality. A number of recent developments have altered our understanding and management of these disorders. The pathogenetic roles of several viruses, including human herpesviruses 6 and 8, have been newly established. Molecular-based diagnostic tests now make more rapid diagnosis possible. The licensing of new potent antiviral agents offers a wider choice of drugs for viral prophylaxis and treatment. The use of more potent immunosuppressive agents is responsible in part for the increasing incidence of some viral infections, but this varies among drugs, and individual viruses differ in their sensitivity to immunosuppressive agents. This review summarizes the natural history, diagnosis, prevention, and treatment of many common viral infections after renal transplantation.

Contributions of total body fat, abdominal subcutaneous adipose tissue compartments, and visceral adipose tissue to the metabolic complications of obesity

Obesity is related to the risk for developing non-insulin-dependent diabetes mellitus (NIDDM), hypertension, and cardiovascular disease. Visceral adipose tissue (VAT) has been proposed to mediate these relationships. Abdominal subcutaneous adipose tissue (SAT) is divided into 2 layers by a fascia, the fascia superficialis. Little is known about the radiologic anatomy or metabolic correlates of these depots. The objective of this study was to relate the amounts of VAT, SAT, deep subcutaneous abdominal adipose tissue (DSAT), and superficial subcutaneous abdominal adipose tissue (SSAT) to gender and the metabolic complications of obesity after adjusting for total body fat and to discuss the implications of these findings on the measurement of adipose tissue mass and adipose tissue function. The design was a cross-sectional database study set in a nutrition research center. Subjects included 199 volunteers participating in nutrition research protocols who also had computed tomography (CT) and dual energy x-ray absorptiometry (DEXA) measurement of body fat. The amount of DSAT was sexually dimorphic, with women having 51% of the subcutaneous abdominal fat in the deep layer versus 66% for men (P <.05). Abdominal fat compartments were compared with metabolic variables before and after adjusting for body fat measured by DEXA using 2 separate methods. The unadjusted correlation coefficients between the body fat measures, R(2), were largest for fasting insulin and triglyceride and smaller for high-density lipoprotein (HDL) cholesterol and blood pressure. A large portion of the variance of fasting insulin levels in both men and women was explained by total body fat. In both men and women, the addition of VAT and subcutaneous abdominal adipose tissue depots only slightly increased the R(2). In men, when body fat compartments were considered independently, DSAT explained a greater portion of the variance (R(2) =.528) in fasting insulin than VAT (R(2) =.374) or non-VAT, non-DSAT subcutaneous adipose tissue (R(2) =.375). These data suggest that total body fat is a major contributor to the metabolic sequelae of obesity, with specific fat depots, VAT, and DSAT also making significant contributions.

Anti-plaque efficacy of a chalk-based antimicrobial dentifrice

A chalk-based antimicrobial dentifrice was developed and has undergone in vitro testing to determine antimicrobial efficacy by kill-time studies, and in vivo clinical studies to determine anti-plaque build-up properties. The antimicrobial efficacy of the formulation is attributable to the following components; sodium lauryl sulphate, sodium monofluorophosphate, flavouring oils, triclosan, and low water activity. In vitro kill-time testing showed the dentifrice to have good activity against organisms associated with plaque, showing at least 99% reductions in the numbers of each organism. In vivo clinical results showed the dentifrice to protect against the build-up of plaque when compared to water alone. These results demonstrate that this dentifrice is effective in controlling plaque, and can thus be expected to promote good oral hygiene.

Access and use of specific dental services in HIV disease

OBJECTIVES

This study examined factors associated with the use of specific dental services by persons with HIV disease.

METHODS

The data were derived from 1,588 adults who participated in a series of up to six interviews as part of the AIDS Cost and Service Utilization Surveys. Use of dental services such as examinations, x-rays, cleaning, fillings, extractions, root canals, crown and bridge or dentures, and periodontal procedures were evaluated using logistic regression and generalized estimating equations were applied.

RESULTS

Multivariate analyses showed that medical insurance, an education beyond high school, income higher than $1,300 per month, high ambulatory visits, and receipt of psychological counseling were generally associated with higher service use. Blacks, those with an inpatient admission, and CD4+ cell counts less than 500 cells/microL were significantly less likely to use most types of dental services.

CONCLUSIONS

The study concludes that disparities exist in the use of several dental services similar to those seen in the general population.

The AIDS drug assistance programs and coverage of HIV-related medications

BACKGROUND

AIDS drug assistance programs (ADAPs) have been implemented in each state to facilitate access to medications for low-income, uninsured, and underinsured people with HIV disease. Policies for each ADAP differ, and these differences influence the access people with HIV have to medications.

OBJECTIVE

To compare the coverage of medications and sources of program funding for the state ADAPs.

DESIGN

A self-administered mailed survey, sent to administrators of the 50 state ADAPs and the District of Columbia ADAP in December 1998.

RESULTS

Forty-nine of the 51 ADAPs (96%) responded to the survey. Title II of the Ryan White Comprehensive AIDS Resources Emergency Act provided a large majority of the funding for the ADAPs, with a number of states also using state funds and/or Title I funds for their programs. The formularies of all ADAPs were nearly identical with respect to coverage of antiretrovirals, but differed in the number and types of other medications included. Some states limited access to medications through waiting lists, enrollment caps, and other policies. Sixteen ADAPs reported that the coverage of protease inhibitors resulted in an appropriation of state government funds to their ADAP, while eight states reported an ADAP budget shortfall. In general, ADAPs in poorer and more rural states included a fewer number of medications on their formularies.

CONCLUSIONS

Access to antiretrovirals and other medications is available through state ADAPs, but may be limited in some states due to waiting lists, controls on the enrollment of new beneficiaries, and policies on the number and types of medications beneficiaries may receive.

Eligibility policies for the state AIDS drug assistance programs

Drug treatments for HIV infection and related opportunistic infections have had dramatic impacts on the morbidity and mortality associated with HIV disease. HIV drug therapies are essential to the survival and to improved quality of life for individuals with HIV. However, not all people with HIV disease are receiving these medications. The state AIDS drug assistance programs (ADAPs) can provide access to drug therapies for many people with HIV disease who lack adequate drug coverage. This research presents the results of a national survey that identified eligibility-related policies implemented by .48 state ADAPs during 1998 and 1999. The survey assessed the number of people receiving ADAP coverage, the percentage of ADAP beneficiaries who are women, financial and medical eligibility requirements, characteristics of the application process, any implementation of waiting lists, and any coordination of the ADAPs with other public programs.

Relationship of dietary fat and serum cholesterol ester and phospholipid fatty acids to markers of insulin resistance in men and women with a range of glucose tolerance

High-fat diets are associated with insulin resistance, however, this effect may vary depending on the type of fat consumed. The purpose of this study was to determine the relationship between intakes of specific dietary fatty acids (assessed by 3-day diet records and fatty acid composition of serum cholesterol esters [CEs] and phospholipids [PLs]) and glucose and insulin concentrations during an oral glucose tolerance test (OGTT). Nineteen men and 19 women completed the study. Nine subjects had type 2 diabetes or impaired glucose tolerance. Fasting insulin correlated with reported intakes of total fat (r = .50, P < .01), monounsaturated fat (r = .44, P < .01), and saturated fat (r = .49, P < .01), but not with trans fatty acid intake (r = .11, not significant [NS]). Fasting glucose also correlated with total (r = .39, P < .05) and monounsaturated fat intakes (r = .37, P < .05). In multivariate analysis, both total and saturated fat intake were strong single predictors of fasting insulin (R2 approximately .25), and a model combining dietary and anthropometric measures accounted for 47% of the variance in fasting insulin. Significant relationships were observed between fasting insulin and the serum CE enrichments of myristic (C14:0), palmitoleic (C16:1), and dihomo-gamma-linolenic (C20:3n-6) acids. In multivariate analysis, a model containing CE 14:0 and percent body fat explained 45% of the variance in fasting insulin, and C14:0 and age explained 30% of the variance in fasting glucose. PL C20:3n-6 explained 30% of the variance in fasting insulin, and a model including PL C18:1n-11 cis, C20:3n-6, age and body fat had an R2 of .58. In conclusion, self-reported intake of saturated and monounsaturated fats, but not trans fatty acids, are associated with markers of insulin resistance. Furthermore, enhancement of dihomo-gamma-linolenic and myristic acids in serum CE and PL, presumably markers for dietary intake, predicted insulin resistance.

Comparison of regional fat distribution and health risk factors in middle-aged white and African American women: The Healthy Transitions Study

OBJECTIVE

Both ethnicity and menopause appear to influence intra-abdominal fat distribution. This study evaluated intra-abdominal fat distribution and obesity-related health risks in perimenopausal white and African American women.

RESEARCH METHODS AND PROCEDURES

Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis.

RESULTS

African American women were slightly younger (46.7 +/- 0.2 vs. 47.7 +/- 0.2 years, p = 0.002) and fatter (42.4% +/- 1.0% vs. 39.4% +/- 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT, although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites.

CONCLUSIONS

Middle-aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.

Reliability and validity of DSM-IV axis V

OBJECTIVE

The authors investigated the reliability and convergent and discriminant validity of the DSM-IV Global Assessment of Functioning Scale and two experimental DSM-IV axis V global rating scales, the Global Assessment of Relational Functioning Scale and the Social and Occupational Functioning Assessment Scale.

METHOD

Forty-four patients admitted to a university-based outpatient community clinic were rated by trained clinicians on the three DSM-IV axis V scales. Patients also completed self-report measures of DSM-IV symptoms as well as measures of relational, social, and occupational functioning.

RESULTS

The Global Assessment of Functioning Scale, Global Assessment of Relational Functioning Scale, and Social and Occupational Functioning Assessment Scale all exhibited very high levels of interrater reliability. Factor analysis revealed that the Global Assessment of Relational Functioning Scale and the Social and Occupational Functioning Assessment Scale are each more related to the Global Assessment of Functioning Scale individually than they are to each other. The Global Assessment of Functioning Scale was significantly related to concurrent patient responses on the SCL-90-R global severity index. The Social and Occupational Functioning Assessment Scale was significantly related to concurrent patient responses on the SCL-90-R global severity index and to a greater degree with both the Social Adjustment Scale global score and the Inventory of Interpersonal Problems total score. Although the Global Assessment of Relational Functioning Scale was not significantly related to any of the three self-report measures, it was related to the presence of clinician-rated axis II pathology.

CONCLUSIONS

The three axis V scales can be scored reliably. The Global Assessment of Relational Functioning Scale and the Social and Occupational Functioning Assessment Scale evaluate different constructs. These findings support the validity of the Global Assessment of Functioning Scale as a scale of global psychopathology; the Social and Occupational Functioning Assessment Scale as a measure of problems in social, occupational, and interpersonal functioning; and the Global Assessment of Relational Functioning Scale as an index of personality pathology. The authors discuss further refinement and use of the three axis V measures in treatment research.

The future of obesity research

As endocrinologists, we view better treatment as the goal of obesity research. The ideal obesity treatment would reduce body fat substantially, with preferential loss from the visceral compartment, and preserve lean tissue with a minimum of side effects. Obesity has been recognized as a chronic disease since 1985. Chronic diseases recognized before obesity may predict the future of obesity research. Initial treatments of chronic diseases commonly arise from empirical observations. These observations often stimulate basic research into the physiologic mechanisms responsible. Such cross-fertilization between the clinic and basic science is desirable and expected. As more is learned about the physiology of obesity, treatments can be expected to use more downstream mechanisms with less unwanted side effects, the reliance on surgical treatments can be expected to decline, and molecular approaches are likely to play an increasingly important role. With a better physiologic understanding of obesity, advanced clinical endpoints will become more important and molecular approaches are likely to play a more important role in discovery and treatment. Due to the availability of molecular approaches, obesity treatment is expected to advance faster than chronic disease research of the past.

Systemic non-Hodgkin's lymphoma presenting as a serpiginous choroidopathy: report of a case and review of the literature

Intraocular lymphoma is a rare tumour, the two main types being primary central nervous system non-Hodgkin's lymphoma (CNS-NHL) and, less commonly, systemic lymphoma that has spread to involve the eye. We present a case of a systemic NHL resulting in a serpiginous choroidopathy. To our knowledge, this presentation has not previously been reported. The diagnosis of this case was made based on the temporal relationship between the clinical activity of the choroidopathy and its response to chemotherapy. Diagnosis of intraocular lymphoma on vitreous biopsy is notoriously difficult, and this case is presented along with a review of the literature regarding vitreous biopsy and diagnostic techniques.

A clinicopathological study of sinonasal neuroendocrine carcinoma and sinonasal undifferentiated carcinoma

OBJECTIVE

Sinonasal undifferentiated carcinoma (SNUC) and sinonasal neuroendocrine carcinoma (SNEC) are relatively newly recognized, rare entities requiring further clinicopathological analysis to advance our understanding and determine prognostic distinctions between them.

STUDY DESIGN

Retrospective chart review.

METHODS

Cases were retrieved from the Copath system. One patient was seen in consultation from an outside institution. Histological and immunohistochemical findings, patient demographics, treatment regimens, and outcomes were analyzed and compared.

RESULTS

Ten patients (7 men, 3 women) ranging in age from 17 to 58 years (mean age, 44.7 y) were included. Four patients were classified with SNEC, six as having SNUC. The predominant site was the superior nasal cavity or ethmoids (seven cases), followed by the maxilla (four cases). Disease in four patients was clinically staged as N1 (three with SNUC, one with SNEC), and in six patients as NO (three with SNEC, three with SNUC). Of the nine patients who were treated initially with surgical resection, seven received postoperative radiation therapy alone, one received postoperative radiation and chemotherapy, and one had only limited postoperative chemotherapy. One patient was treated with radiation therapy and chemotherapy alone, without surgical resection. Follow-up was obtained ranging from 6 to 108 months (mean period, 26.4 mo). Three patients died of disease 10, 14, and 41 months, respectively, after diagnosis. Three patients had persistent disease at 6, 9, and 21 months, respectively, two of them with distant metastases. Four patients were disease free after 6, 18, 31, and 108 months, respectively.

CONCLUSIONS

SNUC and SNEC are both aggressive tumors, usually presenting in middle age as a nasal mass. Both tumors have the capacity to metastasize locally and distantly, and both can result in poor outcomes. This small series precludes a demographic or prognostic distinction between the two groups.

Concurrent physical activity increases fat oxidation during the shift to a high-fat diet

BACKGROUND

It takes several days to adapt to a high-fat diet. In an earlier study, we observed a large degree of interindividual variation in the capacity to adapt to a high-fat diet. We hypothesized that concurrent physical activity would accelerate fat oxidation during an isoenergetic high-fat diet.

OBJECTIVE

The objective of this study was to determine the effect of increased physical activity on the ability of young healthy men to increase fat oxidation during the shift to a high-fat diet.

DESIGN

Six young healthy men participated in a randomized, single-blind crossover study. The volunteers consumed a diet contributing 37% of energy as fat, 14% as protein, and 49% as carbohydrate for 4 d. Energy expenditure and macronutrient balance were then measured in a respiration chamber as the energy content of the isoenergetic diet was changed to 50% fat, 14% protein, and 36% carbohydrate. Treadmill walking, as the physical activity, was used to increase total daily energy expenditure to 1.8 times the resting metabolic rate during 1 of 2 stays in the metabolic chamber. Total daily energy expenditure was maintained at 1.4 times the resting metabolic rate for the other stay.

RESULTS

Energy balance was not significantly different between the 2 conditions. The 24-h respiratory quotient decreased more rapidly and to a greater extent under conditions of increased energy expenditure. Further, there was a decrease in the interindividual variability in the response of the respiratory quotient to a high-fat diet with increased energy expenditure (physical activity). Cumulative carbohydrate and protein balances were greater under conditions of increased physical activity. Conversely, cumulative fat balance was greater under sedentary conditions.

CONCLUSION

Concurrent physical activity increases fat oxidation during the shift to a high-fat diet.

CCR6 mediates dendritic cell localization, lymphocyte homeostasis, and immune responses in mucosal tissue

Chemokine-directed migration of leukocyte subsets may contribute to the qualitative differences between systemic and mucosal immunity. Here, we demonstrate that in mice lacking the chemokine receptor CCR6, dendritic cells expressing CD11c and CD11b are absent from the subepithelial dome of Peyer's patches. These mice also have an impaired humoral immune response to orally administered antigen and to the enteropathic virus rotavirus. In addition, CCR6(-/-) mice have a 2-fold to 15-fold increase in cells of select T lymphocyte populations within the mucosa, including CD4+ and CD8+ alphabeta-TCR T cells. By contrast, systemic immune responses to subcutaneous antigens in CCR6(-/-) mice are normal. These findings demonstrate that CCR6 is a mucosa-specific regulator of humoral immunity and lymphocyte homeostasis in the intestinal mucosa.

Anisotropy of Young's modulus of human tibial cortical bone

The anisotropy of Young's modulus in human cortical bone was determined for all spatial directions by performing coordinate rotations of a 6 by 6 elastic stiffness matrix. The elastic stiffness coefficients were determined experimentally from ultrasonic velocity measurements on 96 samples of normal cortical bone removed from the right tibia of eight human cadavers. The following measured values were used for our analysis: c11 = 19.5 GPa, c22 = 20.1 GPa, c33 = 30.9 GPa, c44 = 5.72 GPa, c55 = 5.17 GPa, c66 = 4.05 GPa, c23 = 12.5 GPa. The remaining coefficients were determined by assuming that the specimens possessed at least an orthorhombic elastic symmetry, and further assuming that c13 = c23 c12 = c11 - 2c66. Our analysis revealed a substantial anisotropy in Young's modulus in the plane containing the long axis of the tibia, with maxima of 20.9 GPa parallel to the long axis, and minima of 11.8 GPa perpendicular to this axis. A less pronounced anisotropy was observed in the plane perpendicular to the long axis of the tibia. To display our results for the full three-dimensional anisotropy of cortical bone, a closed surface was used to represent Young's modulus in all spatial directions.