Medicating the obese patient

The acceptance of medication as a legitimate adjunct to diet and behavior modification in the treatment for obesity is an emerging phenomenon spurred by advances in understanding the biologic basis of body weight regulation and by the demonstration of safe and effective chronic maintenance of weight loss using a pharmacobehavioral approach. The decision to medicate for obesity depends on good clinical judgment based on such considerations as body mass index; body composition; body fat dissociation; age; sex; and comorbid conditions, such as diabetes and hypertension. Several nonadrenergic agents and a serotonergic agent have FDA-approved indications for weight loss. Phenylpropanolamine is available over the counter. Clinical trials support the efficacy of fluoxetine and ephedrine or caffeine in producing weight loss, although these agents do not have FDA-approved indications for treatment for obesity. In addition, new agents are being developed or are anticipated for approval. The use of existing agents in combination and their use adjunctive to diet and behavioral approaches to obesity treatment are fertile areas for research. The expectant attention to this subject is demanded by the imperative that the health in one three people in the United States is adversely affected by obesity.

A double-blind randomized placebo-controlled trial of sibutramine

Sibutramine is a beta-phenethylamine which blocks reuptake of norepinephrine and serotonin. In this clinical study, a group of 173 patients were randomized to treatment with sibutramine at doses of 1, 5, 10, 15, 20 or 30 mg/d and were compared with placebo in a 24-week double-blind trial. There was a dose-dependent reduction in body weight, with doses of 10, 15, 20 and 30 mg being significantly greater than placebo. Weight loss was still continuing in the highest three doses at the end of the study. When drugs were discontinued patients regained weight, as expected. Side effects were generally mild and were most evident in the group treated with the highest dose. These studies suggest that sibutramine may be a valuable new drug for treatment of obesity.

Sibutramine: a novel new agent for obesity treatment

Sibutramine is a novel new pharmacologic agent which is a specific reuptake inhibitor for norepinephrine and serotonin. Preclinical data show that sibutramine and its two metabolites reduce food intake of animals eating either high or low carbohydrate diets and of obese Zucker rats. An 8-week clinical trial showed a dose-dependent decrease on body weight. Sibutramine, 5 and 20 mg/day, produced a dose-related weight loss in obese subjects compared to placebo in an 8-week trial. In doses varying from 1 to 30 mg, sibutramine also produced a dose-dependent decrease in weight in the healthy obese population when used in 6-,8-,12-24- and 52-week trials. Although the majority of the weight loss occurred during the first 12 weeks of treatment, weight loss had not plateaued in by 24 weeks in the higher doses. Side effects were mild. This drug shows promise as an antiobesity drug.

Association of body mass with dietary restraint and disinhibition

The relationship of disinhibition and dietary restraint with body mass was studied in a sample of 293 women. Results suggested that higher body mass was associated with an interaction of disinhibition and dietary restraint. The association of disinhibition with higher body mass was moderated by increased dietary restraint. Symptoms of an eating disorder were more strongly associated with disinhibition than with dietary restraint. These results suggest that dieting may moderate the increased body mass associated with overeating. Psychological and eating problems associated with dietary restraint were found to be of less significance than those associated with disinhibition.

Regulation of human B cell lymphopoiesis by adhesion molecules and cytokines

Recent advances in the ability to culture normal human B cell precursors have emphasized the supportive relationship between these cells and stromal cells in the bone marrow microenvironment. It is now possible to examine the role of adhesion molecules and cytokines in the regulation of different stages of human lymphopoiesis using these culture systems. Direct cell-cell adhesion mediated by the integrin adhesion molecule VLA-4 plays a critical role in supporting stromal dependent proliferation of human B cell precursors. In addition, human B precursor cell lines migrate underneath the stromal layer. This transmigration is VLA-4 dependent but not inhibitable by antibody to known VLA-4 ligands. IL-7 is secreted by the stromal layer, and is necessary for stromal-dependent proliferation of early human B cell precursors. Proliferation of early human B cell precursors or mature B cells. Since the bone marrow stroma is a source of cytokines with B cell precursor growth stimulatory activity, it is possible that adhesion interactions may play a co-stimulatory role with respect to cytokine secretion or response. As the cytokine requirements for human B cell lymphopoiesis become more completely defined, it will be important to uncover the cell-cell signals that regulate lymphopoiesis either directly or through modulation of cytokine secretion by supporting cells in the bone marrow microenvironment. The dependent relationship between human B cell precursors and the bone marrow microenvironment provides a model system for these cell-cell interactions which may be applicable to progenitor development in other lineages.

The association of body weight, dietary intake, and energy expenditure with dietary restraint and disinhibition

The hypotheses that dieting and/or overeating are associated with adiposity, eating disturbances, and lowered energy expenditure were tested in this study. A sample of 44 premenopausal women scoring high and low on measures of dietary restraint and disinhibition of dietary control, as measured by the Three Factor Eating Questionnaire, was studied. A 2 x 2 factorial design was employed (High/Low restraint x High/Low Disinhibition). Dependent variables were: body composition, dietary intake, activity, resting metabolic rate, and thermic effect of food. Unrestrained overeaters (Low Restraint/High Disinhibition group) were very obese. High Dietary Restraint was associated with intent to diet and controlled eating. High scores on the Disinhibition Scale were associated with episodic overeating. Groups did not differ in resting metabolic rate (controlled for fat-free mass). Lower thermic effect of food was found to be associated with the obesity found in High Disinhibition subjects. Thus, Dietary Restraint was not associated with significant adverse effects upon physical or psychological health. High Disinhibition, however, was associated with adiposity and significant disturbances of eating.

A Scottish record linkage study of risk factors in medical history and dementia outcome in hospital patients

The relative risk (RR) of acquiring a hospital diagnosis of dementia was estimated in 101,104 patients (1 in 25 fraction) randomly selected from total admissions to Scottish general hospitals between 1968 and 1977. The patients were allocated to putative at-risk groups according to main diagnosis at time of index admission, and RR of dementia (ICD 9,290) was contrasted between ten risk groups and a reference group. Record linkage was used to reduce admission episodes to individual cases, to link general and psychiatric Scottish Morbidity Records (SMR 1 and SMR 4), to identify subsequent admission diagnoses of dementia, and to establish person-years-at-risk for each case by linking to the Registrar General's mortality file. For males, RR was significantly increased in the 'hypertensive' risk group (RR 3.88:95% CI 2.18-9.89: p < 0.05) and was significantly reduced in the 'arterial disease' risk group (RR 0.57:95% CI 0.34-0.95: p < 0.05). There was a trend towards increased risk in the cerebrovascular category. For females, RR was significantly reduced in the 'cancer' risk group (RR 0.46:95% CI 0.34-0.63: p < 0.05). There was no evidence of significant alteration in RR in a number of other possible risk groups (endocrine, head injury, CNS/NS disease, ischaemic heart disease, peptic ulcer). Morbidity registers provide access to large data sets of low reliability. No attempt was made to distinguish between Alzheimer's disease and multi-infarct dementia cases, which limited scope for comparison with studies focused on Alzheimer's disease. Previous reports positive associations between head injury, thyroid disorder, and subsequent Alzheimer's disease were not replicated.

Mortality before AIDS: a review of causes of death in young men in the city of Edinburgh (1979-88)

Mortality in young Edinburgh males aged 20-34 years was analysed over the period 1979-88. Proportional mortality was calculated from cause of death data: 23% of deaths were caused by accidents, 16% by infection, 15% by suicide and 9% of deaths were due to cancer. Area mortality rates were measured, and rates were significantly higher (P < 0.001) in sectors of low socio-economic status. Edinburgh has the highest HIV positive prevalence rate in the UK (111 per 100,000) and 10% of known UK HIV positive cases in 1988 were traced to Lothian. The Edinburgh rate for AIDS-related deaths in males aged 20-34 years was 0.57 per 100,000, and has been contrasted with the pattern of mortality in New York where the rate was 35.8 per 100,000. The pattern of mortality amongst young Edinburgh males is likely to register a significant change over the next ten years. The results presented may be used as a standard against which change can be measured.

CD34+ progenitor cell isolation from blood and marrow: a comparison of techniques for small-scale selection

The isolation and characterization of primitive hematopoietic cells and their purification in sufficient numbers is important in clinical and research marrow transplantation settings. As systems for large-scale isolation and amplification of such cells are developed, they may assume importance in transplantation, treatment of marrow failure and for gene therapy applications. Such cells have been isolated by numerous techniques and in this work, small-scale isolation of CD34+ cells by two immunoadsorption purification methods is compared with isolation by flow cytometry. While the immunoadsorption techniques allow for the processing of large numbers of density gradient-separated or unseparated cells for progenitor isolation, such techniques do not achieve the purity afforded by fluorescence activated cell sorter separation.

Cytokine regulation of early human lymphopoiesis

An in vitro culture system in which bone marrow-derived fibroblast-like cells support the growth of TdT+ colonies derived from CD34+/CD10- human bone marrow progenitor cells has recently been described. The regulatory role of cytokines during early B lineage commitment was investigated using this culture system. Expression of IL-7, a cytokine that induces proliferation of B cell precursors, was detectable in the adherent layer by PCR and bioassay. Lymphoid progenitor colonies were inhibited by neutralizing anti-IL-7 Ab, suggesting that IL-7 produced by the adherent layer was required even in the earliest recognizable stages of human B cell lymphopoiesis. IL-1 alpha, IL-4, and TNF-alpha inhibited lymphoid progenitor colonies in a dose-dependent fashion. Neutralizing Ab to IL-1 alpha, IL-4, or TNF-alpha did not increase lymphoid progenitor colonies, suggesting that inhibitory concentrations of these cytokines are not constitutively elaborated in the adherent layer. Recombinant Steel factor and IL-6 as well as neutralizing Abs to these cytokines did not significantly affect lymphoid progenitor colonies, arguing against an important role for these cytokines in early human B lymphopoiesis. These results indicate that IL-7 provided by the bone marrow microenvironment is a critical growth factor at the earliest recognizable stages of human lymphopoiesis. IL-1 alpha, IL-4, and TNF-alpha have been shown to indirectly stimulate release of myeloid growth factors. The inhibition of lymphopoiesis by these cytokines suggests a possible mechanism for the observed reciprocal relationship between lymphoid and myeloid supportive bone marrow microenvironments.

Cytokine regulation of early human lymphopoiesis

An in vitro culture system in which bone marrow-derived fibroblast-like cells support the growth of TdT+ colonies derived from CD34+/CD10- human bone marrow progenitor cells has recently been described. The regulatory role of cytokines during early B lineage commitment was investigated using this culture system. Expression of IL-7, a cytokine that induces proliferation of B cell precursors, was detectable in the adherent layer by PCR and bioassay. Lymphoid progenitor colonies were inhibited by neutralizing anti-IL-7 Ab, suggesting that IL-7 produced by the adherent layer was required even in the earliest recognizable stages of human B cell lymphopoiesis. IL-1 alpha, IL-4, and TNF-alpha inhibited lymphoid progenitor colonies in a dose-dependent fashion. Neutralizing Ab to IL-1 alpha, IL-4, or TNF-alpha did not increase lymphoid progenitor colonies, suggesting that inhibitory concentrations of these cytokines are not constitutively elaborated in the adherent layer. Recombinant Steel factor and IL-6 as well as neutralizing Abs to these cytokines did not significantly affect lymphoid progenitor colonies, arguing against an important role for these cytokines in early human B lymphopoiesis. These results indicate that IL-7 provided by the bone marrow microenvironment is a critical growth factor at the earliest recognizable stages of human lymphopoiesis. IL-1 alpha, IL-4, and TNF-alpha have been shown to indirectly stimulate release of myeloid growth factors. The inhibition of lymphopoiesis by these cytokines suggests a possible mechanism for the observed reciprocal relationship between lymphoid and myeloid supportive bone marrow microenvironments.

Sodium bromide acts as a contrast material on DEXA scanning

Subjects undergoing a series of procedures to determine body composition, including dual-energy x-ray absorptiometry (DEXA) scanning and extracellular water volume determination by bromide dilution, demonstrated abnormal DEXA scans in some cases. Oral doses of sodium bromide in the stomach were detected on total body DEXA scanning as contrast material. The physical principles that cause bromide to be imaged in a manner similar to calcium by the DEXA scanner are discussed so that other investigators may be aware of this potential pitfall in body composition analysis.

Age-specific hospital incidence rates in dementia. A record linkage study of first-admission rates to Scottish hospitals (1968-1987)

A random sample (n = 101,104) was taken from total general hospital admissions to Scottish hospitals (1:25 fraction) during the period 1968-1977. Record linkage was used to connect general hospital and psychiatric hospital morbidity records (SMR 1 and SMR 4). Patients with a subsequent admission with dementia (principal diagnosis ICD 9,290) were identified from the general hospital sample on follow-up. Age-specific first-admission rates for dementia were calculated for the hospital population considered. First-admission rates ranged from 41.9 (per 100,000 person-years-at-risk, PYR) for male patients aged 60-64 years to 514.2 in the age band 80 years and over. The equivalent figures for female patients were 40.8 (per 100,000 PYR) and 723.1. Epidemiological research has shown an approximate doubling of prevalence rates every 5 years after the age of 60 years, and the age-banded hospital admission rates in the present study are consistent with this underlying pattern. Expected first-admission rates in dementia were calculated from admission rates in dementia and community prevalence reported in previous studies. Expected rates were contrasted with the rates observed in the present study. An estimated 6-7% of prevalent dementia cases and between 11 and 14% of 'expected dementia admissions' achieved a recorded main diagnosis of dementia, and proportions were stable across age bands in the case of both measures. The wide discrepancy between expected and observed admission rates suggests relative underreporting of dementia as a principal diagnosis in hospital statistics.

Subpopulations of bone marrow fibroblasts support VLA-4-mediated migration of B-cell precursors

Proliferation of normal human lymphoid progenitors in culture is dependent on interaction with bone marrow-derived fibroblast-like cells (BM-FB). To investigate possible heterogeneity in this lymphoid-supportive microenvironment, we studied the interaction of a human B-precursor cell line (NALM-6) with BM-FB. NALM-6 cells associate with BM-FB by either adhesion or migration underneath the fibroblast. Individual fibroblasts in the BM-FB layer showed significant variation in the number of migrating NALM-6 cells. Migration of NALM-6 cells was primarily VLA-4-dependent, although residual migration observable after blocking with anti-VLA-alpha 4 antibody was inhibited by anti-VLA-alpha 5 antibody. Migration was not inhibited by blocking either of the known VLA-4 counterreceptors (VCAM-1 or fibronectin), although slight inhibition was observed using a combination of blocking antibodies to VCAM-1 and fibronectin. In contrast, NALM-6 adhesion without migration was significantly inhibitable by anti-VCAM-1 antibody. VCAM-1 or fibronectin expression on individual BM-FB did not correlate with NALM-6 migration. These results indicate that the adhesion and migration of human B-lymphoid precursors in the bone marrow microenvironment are mechanistically separable events and suggest the possibility of novel VLA-4 ligand(s), which may be important in human lymphopoiesis. Subpopulations of cells in the bone marrow microenvironment may preferentially support important aspects of lymphoid progenitor development.

Expression of integrins and examination of their adhesive function in normal and leukemic hematopoietic cells

Adhesion of hematopoietic progenitor cells to marrow-derived adherent cells has been noted for erythroid, myeloid, and lymphoid precursors. In this report, we have characterized very late antigen (VLA) integrin expression on normal CD34+ marrow progenitors, on leukemic cell lines, and on blasts from patients with acute myelogenous or monocytic leukemias. CD34+ progenitor cells expressed the integrin beta 1 chain (CD29), VLA-4 alpha (CD49d), and VLA-5 alpha (CD49e). The myeloid lines KG1 and KG1a also expressed CD49d and CD49e as did the Mo7e megakaryoblastic line. CD29, CD18, and CD11a were also present on each of these cell lines. Only the Mo7e line expressed the cytoadhesins GPIIbIIIa or GPIb. Binding of KG1a to marrow stroma was partially inhibited by antibodies to CD49d and its ligand, vascular cell adhesion molecule (VCAM-1). The majority of leukemic blasts studied expressed CD49d and CD49e as well. Blasts from patients with acute myelomonocytic leukemia consistently bound to stroma at levels greater than 20%, and adhesion to stroma could in some cases be partly inhibited by anti-CD49d. No role for glycosylphosphatidyl-inositol (GPI)-linked structures was demonstrated in these binding assays because the adhesion of leukemic blasts to stroma was not diminished after treatment with phosphatidylinositol-specific phospholipase C (PI-PLC). These studies indicate that CD34+ myeloid progenitors, myeloid leukemic cell lines, and leukemic blasts possess a similar array of VLA integrins. Their functional importance individually or in combination with other mediators of attachment in adhesion, transendothelial migration, and differentiation has yet to be fully elucidated.

Inhibition of human bone marrow lymphoid progenitor colonies by antibodies to VLA integrins

Studies in animal models suggest that the integrin adhesion protein VLA-4 may play an important role in lymphopoiesis. The relationship between cell adhesion and lymphopoiesis in humans has been difficult to study because of the relative rarity and stringent in vitro growth requirements of lymphoid progenitors from normal adult human bone marrow. To determine the functional significance of VLA-4-mediated adhesion in human lymphopoiesis, we developed a culture system in which a bone marrow-derived adherent layer supports the formation of colonies of terminal deoxynucleotidyl transferase (TdT)-positive lymphoid precursor cells from normal adult human bone marrow. Limiting dilution studies were consistent with clonal origin of these colonies. CFU-TdT were enriched in the CD34+ bone marrow fraction, consistent with CD34 expression by other hematopoietic progenitors. CD34 expression and lack of lineage-specific markers in a significant proportion of the TdT+ colony cells suggest that the TdT+ CFU may represent an uncommitted lymphoid progenitor cell. Development of TdT+ colonies required direct contact with the adherent layer and was significantly inhibited by specific anti-VLA-4 alpha chain antibody, suggesting a functional role for the previously reported VLA-4-dependent adhesion of human B cell precursors to bone marrow-derived fibroblasts.

Inhibition of human bone marrow lymphoid progenitor colonies by antibodies to VLA integrins

Studies in animal models suggest that the integrin adhesion protein VLA-4 may play an important role in lymphopoiesis. The relationship between cell adhesion and lymphopoiesis in humans has been difficult to study because of the relative rarity and stringent in vitro growth requirements of lymphoid progenitors from normal adult human bone marrow. To determine the functional significance of VLA-4-mediated adhesion in human lymphopoiesis, we developed a culture system in which a bone marrow-derived adherent layer supports the formation of colonies of terminal deoxynucleotidyl transferase (TdT)-positive lymphoid precursor cells from normal adult human bone marrow. Limiting dilution studies were consistent with clonal origin of these colonies. CFU-TdT were enriched in the CD34+ bone marrow fraction, consistent with CD34 expression by other hematopoietic progenitors. CD34 expression and lack of lineage-specific markers in a significant proportion of the TdT+ colony cells suggest that the TdT+ CFU may represent an uncommitted lymphoid progenitor cell. Development of TdT+ colonies required direct contact with the adherent layer and was significantly inhibited by specific anti-VLA-4 alpha chain antibody, suggesting a functional role for the previously reported VLA-4-dependent adhesion of human B cell precursors to bone marrow-derived fibroblasts.

Molecular mechanisms of human melanocyte attachment to fibronectin

In this report we show that fetal and neonatal melanocyte attachment to fibronectin (FN) is inhibited by antibodies to the beta 1 integrin subunit, suggesting a role for these molecules in melanocyte attachment to FN. The VLA-5 integrin was shown to be the predominant receptor for fetal melanocyte attachment to FN, in contrast with neonatal melanocytes in which the very late antigen (VLA)-5, VLA-3, and alpha v integrins each contributed to melanocyte attachment to FN. Peptides containing the arginyl-glycyl-aspartyl-serine (RGDS) sequence inhibited fetal and neonatal melanocyte attachment to FN by a maximum of 48% and 85%, respectively. The almost complete inhibition of neonatal melanocyte attachment to FN by RGDS-containing peptides suggests that the central cell-binding domain of FN is the primary recognition site for neonatal cell attachment to FN. Fetal and neonatal melanocytes showed a concentration-dependent attachment to two proteolytically derived fragments of the FN molecule: a 75-kD fragment, which contains the central cell-binding domain, and 33/66-kD fragments of the FN molecule, which encompass the heparin-binding domains V and VI. Antibodies to the beta 1 subunit inhibited fetal and neonatal melanocyte attachment to the 33/66-kD fragments by a maximum of only 15% and 24%, respectively, suggesting that other, non-integrin, receptors are involved in melanocyte recognition of this portion of the FN molecule. We propose that human fetal and neonatal melanocytes attach to FN by different complements of receptors and ligand target sequences, and that these differences may direct melanocyte interactions with FN during development.

A clinical and immunologic study of blood transfusion and postoperative bacterial infection in spinal surgery

Allogeneic blood transfusion has been implicated as an independent risk factor for postoperative bacterial infection in clinical and animal studies. The association among transfusion, quantitative immunologic factors, and infection was examined in 102 patients undergoing 109 spinal fusion procedures. In 60 procedures, patients received autologous blood only; in 24 procedures, they received at least 1 unit of allogeneic blood, and in 25 procedures, they received no transfusions. Twenty-two patients developed bacterial infections, in 8 cases while in hospital and in 14 cases after discharge. Univariate analysis revealed that patients who received any allogeneic blood and those who received no allogeneic blood differed significantly in the rate of hospital-acquired infection (20.8 vs. 3.5%), length of stay (12.3 vs. 9.7 days), days of fever greater than or equal to 38 degrees C (4.0 vs. 2.9), days on antibiotics (3.9 vs. 2.5), duration of surgery (309 vs. 231 min), blood loss (1343 vs. 887 mL), surgeon, and postoperative drop in natural killer (NK) cells (-174 vs. -42/microL). Multivariate logistic and linear regressions revealed that the number of allogeneic units transfused was the only significant predictor of in-hospital infection (p = 0.016) or days on antibiotics and length of stay. None of the clinical, surgical, or transfusion variables was significantly associated with posthospital infection, although a significantly greater drop in NK cells had occurred in patients who developed infection (p = 0.0035). These data strongly implicate allogeneic transfusion as a risk factor for in-hospital postoperative bacterial infection.(ABSTRACT TRUNCATED AT 250 WORDS)