Preadipocyte Recruitment in Stromal Vascular Cultures After Depletion of Committed Preadipocytes by Immunocytotoxicity

Glucocorticoids or the glucocorticoid analog dexamethasone (DEX) enhances the differentiation of preadipocytes in the presence of insulin and influences preadipocyte proliferation. The purpose of the present study was to determine if DEX can induce the recruitment of preadipocytes. Using monoclonal antibodies for complement-mediated cytotoxicity, preadipocytes were removed from porcine stromal vascular (S-V) cell cultures. Our experiments demonstrated for the first time that after removal of preadipocytes by cytotoxicity, preadipocytes or fat cells could be induced by DEX or DEX plus insulin but not by insulin alone. However, many more fat cells were induced (258 ± 15/unit area) when DEX was added with fetal bovine serum (FBS) followed with insulin treatment, compared to DEX with insulin (21.3 ± 5.1/ unit area) after removal of preadipocytes. Immunocyto-chemistry with AD-3, a preadipocyte marker, showed that DEX with FBS for 3 days after seeding (i.e., the proliferation phase) produced many more preadipocytes (AD-3 positive, 223 ± 45/unit area) than FBS alone (10.5 ± 1.4/unit area). Bromodeoxyuridine (BrdU) incorporation assays demonstrated that the efficiency of DEX with FBS (i.e., during proliferation) was mitosis dependent. Accordingly, we conclude that: porcine S-V cultures contain preadipocytes at different stages of differentiation and that DEX induced early preadipocyte differentiation depends on mitosis.     

Chemoprevention clinical trials.

As part of a program to develop drugs which will delay or prevent cancer in humans, the Chemoprevention Branch, National Cancer Institute, National Institutes of Health, is sponsoring 12 Phase I and 22 Phase II and III clinical trials. Three agent classes are significantly advanced in the trials. These are the retinoids, including 13-cis-retinoic acid, retinol, and 4-hydroxyphenylretinamide (nine studies), beta-carotene (seven studies), and calcium compounds (three studies). In addition, six promising new compounds are in Phase I or Phase II trials. These are: piroxicam, ibuprofen, oltipraz (a dithiolthione), difluoromethylornithine, glycyrrhetinic acid, and N-acetylcysteine. Key concepts related to the development of cancer chemopreventive agents are (1) the need for long-term administration, (2) the need for oral route of administration, (3) the matching of toxic side effects to degree of cancer risk.     

Monoclonal antibodies specific to transforming polyproteins encoded by independent isolates of feline sarcoma virus.

Hybridomas secreting monoclonal antibodies directed against polyprotein gene products of the Gardner, Snyder-Theilen, and McDonough strain of feline sarcoma virus have been isolated. Antibody produced by one hybridoma recognizes immunological determinants localized within a feline leukemia virus gag gene structural component (p15) common to polyproteins encoded by each feline sarcoma virus isolate while antibody produced by a second is specific for p30 determinants unique to P170gag-fms. Additional hybridomas secrete antibody directed against v-fes specific determinants common to the Gardner and Snyder-Theilen feline sarcoma virus-encoded polyproteins and to v-fms determinants unique to P170gas-fms polyprotein. GA P110gas-fes and ST P85gas-fes immunoprecipitated by antibody directed against p15 exhibit readily detectable levels of protein kinase activity but lack such activity when precipitated by antibody specific for their acquired sequence (v-fes) components. P170gas-fms immunoprecipitated by monoclonal antibody to either p15 or p30 lacks detectable levels of autophosphorylation but represents a substrate for the GA P110gag-fes and ST P85gag-fes enzymatic activities. These findings argue that the v-fes-associated protein kinase represents an intrinsic property of the v-fes gene product and recognizes tyrosine acceptor sites within polyprotein gene products of all three strains of feline sarcoma virus.     

Chemoprevention strategies in the prostate: an overview

Chemoprevention is the administration of agents (drugs, biologics, and nutrients) to prevent induction, inhibit, or delay the progression of cancers. Prostate cancer is an important target for chemoprevention because of its long latency and high prevalence. The development of rational chemopreventive strategies requires knowledge of the mechanisms of prostate carcinogenesis and identification of agents that interfere with these mechanisms. Because of the long time period for prostate carcinogenesis and the large size of the cohort required for an evaluable study, identification and characterization of early intermediate biomarkers and their validation as surrogate endpoints for cancer incidence are essential for chemopreventive agent development. Finally, suitable populations with appropriate risk factors, including the presence of premalignant lesions and genetic predispositions, need to be well characterized for future chemopreventive interventions.     

Incidence and levels of fumonisin contamination in Colombian corn and corn products

A survey was conducted to determine the levels of fumonisins B1 and B2 in corn and corn-based products available in Colombia for human and animal consumption. A total of 120 samples were analyzed by acetonitrile-water extraction, cleanup with a strong-anion-exchange column, and liquid chromatography with o-phthaldialdehyde-2-mercaptoethanol derivatization and fluorescence detection. The samples of corn and corn-based products for animal intake were taken at different feed manufacturing plants, whereas the samples used for human foods where purchased from local retail stores. The number of positive samples for fumonisin B1 was 20.0% higher in corn and corn-based products for animal intake (75.0%) than in corn and corn-based products for human consumption (55.0%). The levels of fumonisin B1 were also higher in corn and corn-based products for animal intake (mean = 694 μg/kg; range = 32–2964 μg/kg), than in corn and corn-based products for human intake (mean = 218 μg/kg; range = 24–2170 μg/ kg). The incidence and levels of fumonisin B2 were lower than those for fumonisin B1. Corn and corn-based products for animal consumption had an incidence of fumonisin B2 of 58.3%, with a mean value of 283 μg/kg, and a range of 44–987 μg/kg. The incidence of fumonisin B2 in corn-based products for human intake was 35.0%, with a mean value of 118 μg/kg and a range of 21–833 μg/kg. The highest incidence and levels of fumonisins were found in samples of hominy feed, with concentrations ranging from 86 to 2964 μg/kg fumonisin B1 and 57 to 987 μg/kg fumonisin B2.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

Cytomegalovirus seropositivity is associated with glucose regulation in the oldest old. Results from the Leiden 85-plus Study

ABSTRACT: BACKGROUND: Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old. RESULTS: CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%, p = 0.016), had a higher level of HbA1c (p = 0.014) and higher non-fasting glucose (p = 0.024) in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation (all p > 0.05). CONCLUSIONS: In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly.     

Bcl-2 and Bax are differentially expressed in hyperplastic, premalignant, and malignant lesions of mammary carcinogenesis.

Previously, we found that vorozole (Vz), a nonsteroidal aromatase inhibitor, suppresses the development and progression of mammary tumors in rats. Here we evaluated for the first time the expression of cell death-related proteins Bcl-2 and Bax in hyperplastic, premalignant (carcinoma in situ), or malignant (carcinoma) lesions of mammary carcinogenesis; we also assessed whether these proteins are involved in mediating Vz-induced cell death in tumors. We found that Bcl-2 and Bax were equally expressed in epithelial cells of terminal end buds, ducts, and alveoli. However, in myoepithelial cells, the level of Bax expression was much higher than the level of Bcl-2 expression. Bcl-2 and Bax levels in hyperplastic lesions were similar to those of normal mammary epithelial cells but lower in most carcinomas in situ and carcinomas. In animals with established mammary tumors, Vz induced apoptotic cell death, which was primarily associated with a decrease in Bcl-2 and, to a lesser extent, with a decrease in Bax. These data support the hypothesis that Bcl-2 loss is more potent than Bax gain in regulating apoptotic cell death in mammary tumors.     

Sensitive In Vivo Assay for Detection of Murine Leukemia Viruses

A test is reported for the in vivo detection of the replicative ability of murine leukemia viruses (MLV) in the BALB/c mouse strain. Growth in the spleen was assayed by the complement-fixation assay for MLV group-specific antigen after injection of newborn mice. Low doses of laboratory-derived and wild-type MLV from cell-culture and animal-grown sources were detected as early as 7 to 14 days postinoculation. The sensitivity of this in vivo test compared favorably with in vitro assays for MLV. In vivo detection of MLV replication was correlated with long-term oncogenicity.