Effect of physical training and its cessation on percent fat and bone density of children with obesity

OBJECTIVE

We determined the effect of 4-month periods of physical training (PT) and detraining on percent fat (percent fat) and bone density of children with obesity.

RESEARCH METHODS AND PROCEDURES

Subjects were 79 7- to 11-year-old children with obesity; 34 were white, 44 were black, and 1 was Asian, 26 were male and 53 were female. They were randomly assigned to two groups: group 1 engaged in PT for the first 4 months, while group 2 engaged in PT during the second 4 months. Body composition was measured with dual energy absorptiometry, and diet was measured with 4 days of recall for each 4-month period. PT was offered 5 days/week for 40 minutes/session, heart rate monitors were worn, and no dietary information was given; mean attendance was 80%, and mean heart rate per session was 157 bpm.

RESULTS

Group by time interactions across the three time-points (from analysis of variance) were significant for percent fat (p = <0.001) and bone density (p = 0.045). Both groups declined in percent fat during the periods of PT, by an average of 1.6% fat units; in the 4 months after cessation of PT, group 1 increased by 1.3% fat. In both groups, bone density increased more during periods of PT (0.025 g/cm2) than during periods of no PT (0.010 g/cm2). No significant PT vs. no-PT differences were found for dietary intake of energy, macronutrients, or calcium.

DISCUSSION

This study suggests that regular exercise, without dietary intervention, can enhance the body composition of children with obesity.

Effect of physical training on total and visceral fat in obese children

PURPOSE

Children with high levels of total body fat mass (TFM) and visceral adipose tissue (VAT) have elevated levels of certain risk factors for coronary artery disease and non-insulin-dependent diabetes mellitus. We tested the hypothesis that controlled physical training, without dietary intervention, would have a favorable impact on VAT and percent body fat (%BF) in obese children.

METHODS

A volunteer sample of 74 obese children, 7-11 yr of age, accepted random assignment to physical training or control groups. Before and after 4 months of intervention, measurements were obtained for VAT, TFM, %BF, daily physical activity, and cardiovascular fitness. The intervention involved 4 months of controlled physical training 5 d x wk(-1), 40 min per session, at a mean heart rate (HR) of 157 beats x min(-1). The estimated energy expenditure (EE) per training session was 925+/-201 kJ.

RESULTS

Compared with the control group, the physical training group declined significantly in %BF (delta = -2.2%) (P < 0.01), TFM (delta = -3.1%) (P < 0.01), and subcutaneous abdominal adipose tissue (delta = - 16.1%) (P < 0.05), and increased significantly in fat-free mass (delta = +6.1%) (P < 0.05) and moderate-to-very hard physical activity (delta = +14.1%) (P < 0.05). The increase in VAT was significantly less in the physical training group (delta = +0.5%) as compared with that in the control group (delta = +8.1%) (P < 0.05).

CONCLUSIONS

This study showed that during physical training obese children: 1) were capable of participating in a substantial amount of high intensity physical training over a 4-month period: 2) accumulated significantly less VAT as compared with nonexercising controls; and 3) experienced other beneficial changes in total and regional body composition.

Prediction of visceral adipose tissue from simple anthropometric measurements in youths with obesity

OBJECTIVE

Although visceral adipose tissue (VAT) is the component of body composition most highly associated with cardiovascular risk factors, its measurement requires expensive procedures, such as magnetic resonance imaging. This study examined the ability of simple demographic and anthropometric measurements to predict magnetic resonance imaging-derived VAT in 76 apparently healthy, black and white youths with obesity who were 7 years to 16 years of age.

RESEARCH METHODS AND PROCEDURES

Stepwise multiple linear regression was used to develop a prediction equation for VAT based on 13 simple anthropometric variables (height, weight, body mass index, triceps skinfold, calf skinfold, sagittal diameter, waist circumference, hip circumference, thigh circumference, waist/hip ratio, waist/thigh ratio, sagittal diameter/thigh ratio, and percent body fat from the sum of calf and triceps skinfolds) and three demographic variables (age, gender and ethnicity).

RESULTS

The stepwise multiple regression procedure yielded a final model that included two anthropometric variables (sagittal diameter and waist/hip ratio) and one demographic variable (ethnicity). The prediction equation was: VAT = - 124.06+ 16.67 (ethnicity)+4.15 (sagittal diameter)+100.89 (waist/hip ratio), where ethnicity was coded as 0= black and 1 = white. The model explained 63% of the variance in VAT and was associated with a measurement error of 23.9%.

DISCUSSION

Although the model seems to lack sufficient explanatory power for routine use in clinical settings with individual patients, it may have some utility in epidemiological studies given its relatively small (<25%) standard error of estimate.

Inactivating mutations in an SH2 domain-encoding gene in X-linked lymphoproliferative syndrome

X-linked lymphoproliferative syndrome (XLP) is an inherited immunodeficiency characterized by increased susceptibility to Epstein-Barr virus (EBV). In affected males, primary EBV infection leads to the uncontrolled proliferation of virus-containing B cells and reactive cytotoxic T cells, often culminating in the development of high-grade lymphoma. The XLP gene has been mapped to chromosome band Xq25 through linkage analysis and the discovery of patients harboring large constitutional genomic deletions. We describe here the presence of small deletions and intragenic mutations that specifically disrupt a gene named DSHP in 6 of 10 unrelated patients with XLP. This gene encodes a predicted protein of 128 amino acids composing a single SH2 domain with extensive homology to the SH2 domain of SHIP, an inositol polyphosphate 5-phosphatase that functions as a negative regulator of lymphocyte activation. DSHP is expressed in transformed T cell lines and is induced following in vitro activation of peripheral blood T lymphocytes. Expression of DSHP is restricted in vivo to lymphoid tissues, and RNA in situ hybridization demonstrates DSHP expression in activated T and B cell regions of reactive lymph nodes and in both T and B cell neoplasms. These observations confirm the identity of DSHP as the gene responsible for XLP, and suggest a role in the regulation of lymphocyte activation and proliferation. Induction of DSHP may sustain the immune response by interfering with SHIP-mediated inhibition of lymphocyte activation, while its inactivation in XLP patients results in a selective immunodeficiency to EBV.

Changes in matrix composition during the growth and regression of human hemangiomas

BACKGROUND

Hemangiomas offer an uncommon opportunity to study rapid vessel growth and spontaneous regression of a vascular human tumor. In contrast, venous malformations are another type of vascular tumor that grows slowly without spontaneous involution. Extracellular matrix (ECM) molecules modulate the responsiveness of endothelial cells to mitogenic stimuli such as basic fibroblast growth factor (bFGF), a well-recognized stimulant of angiogenesis. In this study we hypothesized that in hemangiomas, sites of angiogenesis may have a different ECM composition than sites of vascular regression.

MATERIALS AND METHODS

Using immunohistochemistry, we analyzed proliferating hemangiomas, regressing hemangiomas, venous malformations, and normal skin for the basement membrane ECM molecules collagen IV and laminin and plasma-borne ECM molecules fibronectin and vitronectin. We used metabolic labeling to determine whether primary human dermal microvascular endothelial cells regulated FGFR-1 or FGFR-2 when grown on these different matrices.

RESULTS

We found that proliferating hemangiomas showed extensive deposition of vitronectin in the subendothelial space. In contrast, regressing hemangiomas or venous malformations did not show vitronectin deposition. Venous malformations, which are composed of ectatic lakes of venous channels, also lacked laminin in their basement membranes. We also found that cultured microvascular endothelial cells grown on vitronectin increased synthesis of FGFR-1 and FGFR-2 protein.

CONCLUSIONS

Changes in the ECM environment occur in conjunction with the angiogenic state of a vascular human tumor. Furthermore, changes in the ECM environment alone can directly regulate synthesis of angiogenic growth factor receptors.

Comparison of apolipoprotein and proteoglycan deposits in human coronary atherosclerotic plaques: colocalization of biglycan with apolipoproteins

BACKGROUND

Because the content of specific proteoglycans and apolipoproteins is increased in atherosclerotic plaques and in vitro studies have suggested a role for proteoglycans in mediating plaque apolipoprotein (apo) retention, immunohistochemistry was performed to systematically examine the relative locations of proteoglycans and apolipoproteins in human atherosclerosis.

METHODS AND RESULTS

The spatial relationships of versican, biglycan, and apoE were compared on 68 human coronary artery segments; apoA-I and apoB also were evaluated on an additional 20 segments. Nonatherosclerotic intima contained extensive deposits of versican, whereas deposits of apoE, apoB, and apoA-I were much less prevalent. In contrast, nearly all atherosclerotic segments contained substantial deposits of biglycan, apoE, apoA-I, and apoB. There was a high degree of colocalization of apoE and biglycan deposits. ApoA-I, the major apolipoprotein of HDL, and apoB also were detected in regions with apoE and biglycan deposition. Exceptions to the localization of biglycan with apolipoproteins were found in regions that lacked intact extracellular matrix because of necrosis or dense macrophage accumulation. In vitro studies demonstrated that biglycan binds apoE-containing but not apoE-free HDL and that biglycan also binds LDL.

CONCLUSIONS

These results suggest that biglycan may bind apoE and apoB in atherosclerotic intima. They also raise the possibility that apoE may act as a "bridging" molecule that traps apoA-I-containing HDL in atherosclerotic intima. Taken together, these findings are consistent with the hypothesis that biglycan may contribute to the pathogenesis of atherosclerosis by trapping lipoproteins in the artery wall.

T wave alternans associated with HIV cardiomyopathy, erythromycin therapy, and electrolyte disturbances

We report a case of T wave alternans in a patient with HIV cardiomyopathy. T wave alternans is an unusual electrocardiographic finding in acquired long QT syndromes that can precede the development of torsades de pointes. Our patient had multiple risk factors for the development of the acquired long QT syndrome, including HIV cardiomyopathy, electrolyte disturbances, and erythromycin therapy. T wave alternans has not been described previously with HIV cardiomyopathy and only rarely with erythromycin therapy. Patients who have HIV cardiomyopathy and who receive intravenous erythromycin may benefit from monitoring for QT prolongation and electrolyte disturbances to avoid the development of torsades de pointes.

Visceral adipose tissue and cardiovascular risk factors in obese children

OBJECTIVE

In adults visceral adipose tissue (VAT) has been shown to be more highly correlated with cardiovascular (CV) risk factors than are other measures of adiposity such as subcutaneous abdominal adipose tissue (SAAT), percent body fat (%BF), or total body fat mass (TFM). We examined the relations between these measures of fatness and CV risk factors in obese children.

STUDY DESIGN

Subjects were 64 obese (27% to 61% BF) children (24 black girls, 19 white girls, 11 black boys, 10 white boys) aged 7 to 11 years. VAT and SAAT were measured with magnetic resonance imaging. TFM and %BF were determined with dual x-ray absorptiometry. Hierarchical stepwise multiple regression analyses were used to determine the proportions of variance in CV risk factors explained by the demographic and adiposity measures.

RESULTS

VAT but not SAAT, %BF, or TFM explained a significant proportion of the variance (r2 range = 0.10 to 0.21) in several lipid/lipoprotein risk factors including triacylglycerols, high-density lipoprotein cholesterol, the ratio of total cholesterol to high-density lipoprotein cholesterol, and low-density lipoprotein particle size.

CONCLUSION

Many of the deleterious relations between VAT and lipid/lipoprotein risk factors seen in adults were already present in this sample of obese children.

Up-regulation of elastase in acute wounds of healthy aged humans and chronic venous leg ulcers are associated with matrix degradation

Chronic wound healing states are often associated with aging, and despite the increased number of aged patients with nonhealing wounds, controversy still exists concerning the effects of age on wound repair. Our previous work showed that in both venous ulcers in humans and acute wounds in aged animals, fibronectin, an early component in granulation tissue, is deficient compared to normal skin and acute wounds in healthy young animals, respectively. In the present study, we have determined the protease responsible for fibronectin degradation by analyzing tissue taken from the margins of chronic venous ulcers and standardized acute cutaneous wounds collected from a large cohort of "Health status"-defined aged human subjects (screened as per the SENIEUR protocol). When tissue samples were subjected to fibronectin zymography, the main protease involved in the breakdown of fibronectin in both venous ulcers and acute wounds of elderly subjects was found to be a serine protease with a molecular weight of approximately 30 kd. This protease was identified as neutrophil elastase by immunoblotting. In tissue biopsies, elastase was localized to granulocytes by immunocytochemical techniques and shown to be present in greater quantities in venous ulcers and Day-7 and -14 healing acute wounds of healthy aged subjects relative to those of young subjects. The highest quantities were found in acute wounds of elderly women. Our results suggest that the process of aging in healthy human subjects is associated with an up-regulation of elastase during acute wound healing and that an abnormality in down-regulation of this protease could be partially responsible for the transition to chronic wound healing states in the aged.

Report of a collaborative study to establish the international standard for parvovirus B19 serum IgG

With the introduction of commercial test kits and the wider availability of parvovirus B19 antibody testing, greater standardization is required. Moreover, with a B19 vaccine in the early stages of development, there will be long-term need of accurate measurement of parvovirus B19 antibody levels following natural infection and vaccination. A collaborative study was carried out to assess the suitability of a freeze-dried preparation designated 93/724 to serve as the International Standard for parvovirus B19 serum IgG. The proposed standard, which is a pool of sera from six U.K. blood donors, was assayed along with three coded samples. One was the proposed standard (Preparation A), one a pool of three donor sera (Preparation B) and the third an individual donor serum (Preparation C). These preparations were sent to nine laboratories in seven countries who tested them in 10 different enzyme immunoassays. There were no differences in the antibody content expressed relative to that of the proposed standard in assays using native or recombinant antigen. However, antibody was not detected in serum from an individual blood donor (Preparation C) in assays performed using kits which contained recombinant VP1 but not VP2. This highlights the differences which may be obtained in commercial kits which contain different antigens. The results of this study demonstrated that the proposed standard coded 93/724 is suitable to serve as the International Standard for parvovirus B19 serum IgG and this material has been established as the International Standard for parvovirus B19 IgG by the World Health Organization with an assigned unitage of 100 lU per ampoule. The standard, which is a pool of what can be assumed to be convalescent sera, will be suitable for standardizing diagnostic tests for use in seroprevalence studies and for assessing immunity. An additional standard will be required to standardise tests specifically for the detection of IgM and the diagnosis of acute infection.

Potency of wild-type or sabin trivalent inactivated poliovirus vaccine, by enzyme-linked immunosorbent assay using monoclonal antibiotics specific for each antigenic site

Potency testing of inactivated poliovirus vaccine (IPV) is hampered by the absence of a standardized in vitro test, as well as the lack of a generally accepted quantitative animal test. In vitro tests must be able to measure selectively the content of the "D" antigen in the vaccine which includes virus neutralizing antibodies. We tested 12 poliovirus type 1, 12 type 2 and six type 3, D antigen-specific monoclonal mouse antibodies (mAb) for use in the enzyme-linked immunosorbent assay (ELISA). We characterized the site-specific reactivities of three mAbs, one for each poliovirus type. The reactivity of the complete mAb panel encompassed the important antigenic sites on the virus surface of each of the poliovirus serotypes. Some of the mAbs were cross-reactive between wild-type and Sabin strain IPV. At least one mAb of each poliovirus type that was D antigen-specific and reacted with both wild-type and Sabin IPV was directed against an antigenic site thought to be immunogenic in humans. These reagents may be useful for improved standardization of the ELISA for IPV.

Monocyte chemoattractant protein-1 mRNA expression in the human burn wound

The inflammatory response following a thermal insult begins with the skin itself. Langerhan's cells, tissue macrophages, keratinocytes, fibroblasts, and endothelial cells contribute to the initial events of wound healing with active and passive release of cell mediators. One of the mediators potentially important to the repair process is monocyte chemoattractant protein-1 (MCP-1). Macrophages, fibroblasts, endothelial cells, and keratinocytes can produce MCP-1 in response to inflammatory stimuli. Therefore, we evaluated 10 human burn wound specimens for MCP-1 mRNA using in situ hybridization. Selected specimens of different ages were examined using combined in situ hybridization and immunocytochemistry to identify cell types that expressed MCP-1 mRNA. Antibodies to HAM56 for macrophages, CD45 for bone marrow-derived cells, Factor VIII for endothelial cells, and Factor XIIIa for dermal antigen-presenting cells were included in these experiments. By Postburn Day 2, basal layer keratinocytes at the edges of the wound had upregulated MCP-1 message; the increased signal persisted in the rate pegs deep in the dermal wound bed through 49 days postinjury. Occasional FXIIIa+ immunostained dermal cells expressed MCP-1 mRNA. Islands of granulation tissue throughout the wound bed were positive for increased expression of MCP-1; endothelial cells and inflammatory cells both contributed to this upregulated signal. Our data support the theory that the skin itself is a component of the immune system and that noninflammatory cells contribute to the initiation and maintenance of the inflammation at a wound site. Failure to produce MCP-1 or other related mediators by indigenous cutaneous cells may delay the inflammatory response to injury and potentially disrupt other essential phases of wound repair.

Comparison of Fy(b) status as determined serologically and genetically

Comparison of the serologically determined phenotype and the genotype of samples as defined by PCR-RFLP indicated a significant percentage of discrepancies on analysis of serologically defined Fy(a + b-) samples. An investigation of these discrepancies has shown that the serologically determined phenotype of the samples varies with respect to the reagent used but that the PCR-RFLP assay gives reliable results for all the samples investigated. The samples which yielded the discrepant results were further investigated and the results indicated weakened expression of the Fyb antigen. This may arise by a method similar to the expression of Fyx although we found the incidence of these samples to be much higher than that reported for Fyx. These results may have important implications for the routine testing of blood donations, particularly in situations where the unit is to be transfused to a patient who has previously formed an anti-Fyb.

Use of pleural catheter for the management of simple pneumothorax

STUDY OBJECTIVE

We assessed the use of a pleural catheter (Thoracic Vent) to determine its effectiveness in treating simple pneumothorax (PTX) and in preventing recurrent PTX.

DESIGN

A retrospective review was conducted of 84 patients treated with a pleural catheter for iatrogenic (52) and spontaneous (11 primary, 21 secondary) PTX between 1989 and 1994.

PATIENTS

There were 45 men and 39 women with a mean age of 50.4 years (range, 18 to 85 years).

RESULTS

Mean time to lung reexpansion was 0.5 +/- 0.1 days. Forty-five (57%) patients manifested an air leak after catheter placement for 2.0 +/- 0.2 days. The duration of time to catheter removal was 3.3 +/- 0.2 days. Seventy-one (85%) patients had resolution of PTX with this therapy alone. Thirteen patients (15%) failed to resolve their PTXs and required subsequent tube thoracostomy alone (6) or surgical therapy (7). Four of 11 patients who required tube thoracostomy also failed to respond to this therapy. Treatment failure was more common among patients with spontaneous PTX than with iatrogenic PTX (34% vs 4%; p < 0.005). During a mean follow-up of 3.0 +/- 0.2 years, 6 (7%) patients suffered recurrent PTX an average of 23 days after initial therapy.

CONCLUSION

This pleural catheter is effective in the management of simple iatrogenic and spontaneous PTX.

Management of blunt chest injury

The development of regional techniques of analgesia has revolutionized the management of blunt thoracic trauma. The standard of care has evolved from intubation and mechanical ventilation for all patients to optimization of pain control combined with chest physiotherapy. Although many methods have been used, it appears that in appropriately selected patients, epidural analgesia is the preferred technique for pain control in severe thoracic trauma. Epidural catheters for continuous narcotic or local anesthetic administration are both the most reliable and the most effective, and once in place they can be managed by nursing outside of the intensive care setting. It still remains for improvement in outcome to be demonstrated when epidural analgesia is used, but it is clear that subjective patient comfort is increased and that pulmonary parameters can be improved. In appropriately selected patients, those without head injury or who have been adequately evaluated for intra-abdominal injury, epidural analgesia is currently the preferred method for pain control following severe thoracic trauma.

Testing plasma pools for markers of viral contamination: the UK experience

The transmission of viral infections through the use of products derived from blood has emphasised the need for adequate validation of the production process, testing of materials used in production and quality control tests on the final product. Since the late 1980s, as part of its batch release procedures, NIBSC has tested for markers of viral infectivity plasma pools used in production of blood products used in the UK. As a result of testing over 9,000 pools, NIBSC has identified 9 pools contaminated with HBsAg and 2 pools containing antibodies to HIV-1. Since routine screening of plasma pools for anti-HCV was introduced in 1993, 8 pools out of the 4,000 tested have been found to contain antibodies to HCV. In addition, the release of 12 batches of blood products was withheld and it is known that further batches of material produced from the positive pools were not submitted for batch release. Studies involving assays of dilutions of known positive plasma samples indicated that there is considerable variation in the endpoint dilutions of antigen or antibody detected by test kits from different manufactures. The selection and validation of the kits used in such testing is therefore important. The usefulness of standardised low-level external controls in assays of plasma pools for markers of viral infection is discussed.

Vinorelbine (Navelbine), cisplatin, and concomitant radiation therapy for advanced malignancies of the chest: a Phase I study

Most patients with advanced solid tumors of the chest will have local and/or distant disease progression despite standard therapy. Vinorelbine (Navelbine; Burroughs Wellcome Co, Research Triangle Park, NC; Pierre Fabre Medicament, Paris, France) is a new semisynthetic vinca alkaloid with single-agent activity in lung cancer that recently also has been shown to act as a radiosensitizer in vitro. This study aims to define the maximum tolerated dose and dose-limiting toxicity when vinorelbine is given with cisplatin and concomitant radiation therapy. To date, 25 patients with advanced malignancies of the chest have been treated in a dose-escalation trial of vinorelbine administered once weekly with cisplatin (100 mg/m2 every 21 days) and concomitant thoracic radiation therapy (2 Gy/d x 30 fractions for 60 Gy). Vinorelbine was initially given at 20 and 25 mg/m2/wk. Acute dose-limiting toxicity was myelosuppression, which was seen at a vinorelbine dose of 25/mg/m2/wk, with grade 4 neutropenia in two of three patients and one treatment-related death from neutropenic sepsis. At vinorelbine 20/mg/m2/wk, no acute dose-limiting toxicity was seen, but grade 3 or 4 esophagitis developed in three of six patients near the end or after completion of radiation therapy. We subsequently decreased the administration of vinorelbine to weeks 1, 2, 4, and 5. Tolerance appears to be greater with this schedule; however, severe or life-threatening esophagitis at the completion of therapy continues to be observed. Given these preliminary results, it appears feasible to treat patients with advanced chest malignancies with concomitant cisplatin, vinorelbine, and radiation therapy. The significant dose reduction of vinorelbine that is necessary with concomitant radiation therapy provides the first in vivo evidence of a strong radiosensitizing effect of vinorelbine. The schedule is currently being modified to reduce the incidence of esophagitis.

Another case of virologically confirmed zoster sine herpete, with electrophysiologic correlation

A third virologically-confirmed case of thoracic-distribution zoster sine herpete is reported. Electromyography (EMG) of paraspinal muscles demonstrated frequent fibrillation potentials restricted to chronically painful thoracic root segments. Treatment with intravenous acyclovir and oral famciclovir were ineffective. These findings suggest the usefulness of EMG of muscles corresponding to painful dermatomes, combined with virologic studies, to support the diagnosis of zoster sine herpete.

Expression of collagen, interstitial collagenase, and tissue inhibitor of metalloproteinases-1 in restenosis after carotid endarterectomy

Extracellular matrix is the principal component of the fibrous caps of atherosclerotic plaques and intimal hyperplastic lesions of reconstructed arteries. Interstitial collagen form an important part of the matrix, and the balance between collagen synthesis and degradation by interstitial collagenase (matrix metalloproteinase-1, MMP-1) may determine whether plaques rupture or vessels develop stenosis. We examined type I procollagen gene expression in human atherosclerotic and restenotic carotid arteries using in situ messenger RNA (mRNA) hybridization and the expression of MMP-1 and its endogenous inhibitor (tissue inhibitor of metalloproteinases-1, TIMP-1) by immunohistochemistry. Compared with normal arteries, atherosclerotic plaques bed increased expression of immunoreactive MMP-1 and TIMP-1 with modest increase of type 1 procollagen mRNA. Early restenotic lesions (< 1.5 years) contained abundant type I procollagen mRNA but little immunoreactive MMP-1 and TIMP-1. Late restenotic lesions (> 4 years) resembled atheroma and exhibited increased immunoreactive MMP-1 and TIMP-1 as well as abundant type I procollagen mRNA. Compared with atherosclerotic plaques, type I procollagen is increased and MMP-1 is decreased in early restenotic lesions. MMP-1 and TIMP-1 expressions are upregulated in lesions with a clear atheroma. These findings suggest that the balance between proteolysis and matrix synthesis may influence both the stability of atheromatous plaques and the development of restenotic lesions.