Multiple interactions between the alpha<Subscript>2C</Subscript>- and beta<Subscript>1</Subscript>-adrenergic receptors influence heart failure survival

Background  

Persistent stimulation of cardiac β₁-adrenergic receptors by endogenous norepinephrine promotes heart failure progression. Polymorphisms of this gene are known to alter receptor function or expression, as are polymorphisms of the α_2C-adrenergic receptor, which regulates norepinephrine release from cardiac presynaptic nerves. The purpose of this study was to investigate possible synergistic effects of polymorphisms of these two intronless genes (ADRB1 and ADRA2C, respectively) on the risk of death/transplant in heart failure patients.     

Fibrinogen biosynthesis in isolated guinea pig megakaryocytes

Fibrinogen synthesis was investigated in guinea pig megakaryocytes. Purified megakaryocytes were incubated with 35S-methionine in methionine-free incubation medium for 18 hours. Newly synthesized fibrinogen in megakaryocyte lysates enriched with purified carrier guinea pig fibrinogen was immunoprecipitated with a specific anti- guinea pig fibrinogen antiserum produced in rabbits. Proteins in the immunoprecipitates were analyzed with a 3.5% to 10.0% gradient polyacrylamide slab gel electrophoresis and auto-radiography. Radioactivity was detected in a protein band of 340,000 daltons. In order to verify fibrinogen synthesis, immunoprecipitate was analyzed by two-dimensional slab gel electrophoresis: (1) the first dimension separated unreduced fibrinogen using a 3.5% to 10.0% gradient gel; (2) following reduction by 2-beta-mercaptoethanol, fibrinogen chains were separated in the second dimension using a 10% gel. Alpha, beta, and gamma fibrinogen chains, which represented carrier guinea pig plasma fibrinogen, were visualized by Coomassie brilliant blue. Autoradiography identified the incorporation of radioactivity into the three fibrinogen chains. In control experiments, immunoprecipitates, produced by exposing megakaryocyte lysates to preimmune rabbit serum and goat anti-rabbit IgG, were also analyzed by the two-dimensional gel system. Radioactivity was not detected in sites corresponding to the migration of fibrinogen subunits. The study demonstrates that isolated guinea pig megakaryocytes can synthesize fibrinogen. The electrophoretic mobility of newly synthesized fibrinogen and subunits is similar to that of guinea pig plasma fibrinogen.     

A mechanism for effective cell-seeding in rigid,microporous substrates

Seeding cells into porous ceramic substrates has been shown to improve outcomes in surgical repair of large bone defects, but the physics underlying cellular ingress into such scaffolds remains elusive. This paper demonstrates capillary forces as a novel, yet simple, self-loading or self-seeding mechanism for rigid, microporous substrates. Capillary forces were found to draw cells through a microporous network with interconnections smaller than the diameter of the cells in suspension. Work here emphasizes CaP-based bone scaffolds containing both macroporosity (>100 μm) and microporosity (5–50 μm); these have been shown to improve bone formation in vivo as compared to their macroporous counterparts and also performed better than microporous scaffolds containing BMP-2 by some measures of bone regeneration. We hypothesize that capillary force driven self-seeding in both macro- and micropores may underlie this improvement, and present a mathematical model and experiments that support this hypothesis. The cell localization and penetration depth within these two-dimensional substrates in vitro depends upon both the cell type (size and stiffness) and the capillary forces generated by the microstructure. Additional experiments showing that cell penetration depth in vitro depends on cell size and stiffness suggest that microporosity could be tailored to optimize cell infiltration in a cell-specific way. Endogenous cells are also drawn into the microporous network in vivo. Results have important implications for design of scaffolds for the healing of large bone defects, and for controlled release of drugs in vivo.     

Recurrent primary cardiac malignant fibrous histiocytoma following orthotopic heart transplantation

Malignant fibrous histiocytoma (MFH) is an extremely rare primary cardiac tumor. We describe a young patient who underwent orthotopic heart transplantation for an unresectable right ventricular MFH and presented 7 years later with a local recurrence in the native right atrium. This was treated by complete resection of the right atrial tumor and adjuvant chemotherapy. This case represents the only reported long-term survival following cardiac transplantation for MFH and describes our management strategy for local recurrence in this patient.     

Beryllium: An etiologic agent in the induction of lung cancer,nonneoplastic respiratory disease,and heart disease among industrially exposed workers

On the basis of the clear demonstration of the carcinogenicity of beryllium in several animal species along with the suggestion of an increased risk of lung cancer mortality in humans exposed to beryllium, an epidemiologic study of workers exposed to beryllium at one production facility was undertaken. Within the limitations imposed by the selection of data for calculation of cause-specific expected mortality (use of U.S. white male cause-specific mortality rates with linear extrapolation of 1965–1967 to 1968–1975 vs use of cause-specific mortality rates for the county in which the study facility and the majority of its workers resided), the study demonstrated a statistically significant increased risk of respiratory disease (neoplastic and nonneoplastic) and of heart disease mortality. A possible explanation other than in terms of beryllium was sought for this excessive risk of cause-specific mortality among beryllium-exposed workers. The excessive risk of lung cancer mortality could not be related to an effect of age, chance, self-selection, study group selection, exposure to other agents in the study facility, or place of residence. On the basis of the frequency of cigarette smoking among those cohort members employed in 1967–1968 and the distribution of histologic types of lung cancer among deceased cohort members, it seems unlikely that cigarette smoking per se could have accounted for the increased risk of lung cancer among beryllium-exposed workers in the study cohort. Lifetime employment histories for members of the study cohort were not available, so that definitive statements about the role of other occupational exposures cannot be made. However, information on usual occupations as indicated on death certificates suggests that it is unlikely that some undefined occupational or environmental exposure other than to beryllium could account per se for the excessive lung cancer mortality. This interpretation is further supported by the residential stability of the study cohort in a county having a lung cancer rate significantly lower than that of the entire United States. The findings of a statistically significant excess of lung cancer mortality among cohort members in general (P < 0.05) and among workers observed 25 or more years since onset of beryllium exposure in particular (P < 0.01), when taken in context with the results of earlier animal bioassay and recent epidemiologic studies, are supportive of the hypothesis that beryllium is carcinogenic to man.     

Real Time-PCR HBV-DNA Analysis: Significance and First Experience in Armed Forces

Background

HBV DNA quantitation is used extensively world wide for the diagnosis and monitoring of treatment of Hepatitis B virus (HBV) infection. However, it has still to be popular in India. The aim of this study was to quantitate HBV – DNA by Real time – PCR method in Hepatitis B and in immuno-compromised patients, to compare the results with HBeAg detection and to monitor the response to therapy of chronic Hepatitis B patients to antivirals.

Methods

Ninety one serum samples of Hepatitis group of patients (all HBsAg positive), 41 samples from immuno-compromised patients (all HBsAg negative) and 49 patients of Chronic Hepatitis B group (all HBsAg positive) were the subjects of this first ever study in Armed Forces. Twenty serum samples from healthy volunteers and non-hepatitis B patients served as negative controls. The amplification detection was carried out in a Rotor-Gene 2000-sequence detector

Results

Amongst Hepatitis B group, 33% (30/91) of the samples were positive for HBV-DNA and 26% (24/91) of samples were positive for HBeAg. In the immuno-compromised group of patients 14.6% (6/11) of samples were positive for HIV-DNA and 9.7% (4/41) were positive for HBeAg. Of the Chronic Hepatitis B patients on treatment, all (100%) were positive by HBV-DNA, whereas 29/49 (59.2%) were positive by HBeAg before treatment. After treatment with antivirals, 06/49 (12.2%) were positive by both tests and 11/49 (22.5%) were positive only by HBV-DNA. 32/49 (65.3%) patients became negative serologically after therapy.

Conclusion

HBeAg status did not necessarily reflect HBV-DNA level in the serum, as 10/91 (11%) in the Hepatitis B group, 2/41 (4.9%) in the immuno compromised group and 20/49 (40.8%) patients in the Chronic Hepatitis B group were positive for HBV-DNA but negative for HBeAg. HBV-DNA was not found to be positive amongst any of the negative controls. Real time – PCR is a sensitive and reproducible assay for HBV-DNA quantitation and may be started in Armed Forces referral centers in the near future.Key Words: Real time – PCR, Chronic Hepatitis B, HBV – DNA, Antivirals