A Case of Large Calcifying Fibroma of Tendo-achilles Managed by En-block Resection and Tendon Reconstruction

Calcifying aponeurotic fibroma is a rare benign fibrous tumor with typical radiological and histopathological features seen in young children and adolescents. It commonly involves the extremities and is characterized by a very high chance of local recurrence. A complete excision of the tumor is considered to be the treatment of choice. We report a case of the tumor involving the substance of achilles tendon and extending up till its insertion in the calcaneum. To the best of our knowledge, this is the largest reported case of calcifying fibroma, with the tumor measuring 10 cm in its largest diameter. The tumor was excised in toto followed by reconstruction of the tendon defect with V-Y plasty of the native tendon and supplemented with semitendinosus and gracilis graft. There was no evidence of recurrence during the follow up period of 1 year.     

Determinants of Hepatitis B Virus (HBV) Infection Among University Students in Central Bangladesh

This study aimed to determine the seroprevalence and determinants of hepatitis B virus (HBV) infection among university students in Bangladesh. This cross-sectional study was conducted among 614 students from five universities in central Bangladesh. Data were collected on demographic information, immunization history, medical and blood transfusion history through the face-to-face interview. Blood samples were collected and screened for anti-HBsAg using ELISA, HBsAg Rapid Test-cassette, and immune chromatographic test. The overall seroprevalence of HBV infection was 5.0%, and vaccination coverage was 19.2% among the participants. Students having a history of surgery (OR 11.004, 95% CI 3.211–37.707), blood transfusion (OR 5.651, 95% CI 0.965–33.068), being married (OR 4.776, 95% CI 1.508–15.127), and not being vaccinated (OR 9.825, 95% CI 1.130–85.367) were at higher risk of being infected by HBV. This study showed the endemicity of HBV infection among the Bangladeshi population. Marriage, surgical or blood transfusion history, not being vaccinated were the determinants of HBV infection within the study population. Public health initiatives for preventing HBV infection at the university levels should be envisaged.

     

Dengue determinants: Necessities and challenges for universal dengue vaccine development

Dengue illness can range from mild illness to life-threatening haemorrhage. It is an Aedes-borne infectious disease caused by the dengue virus, which has four serotypes. Each serotype acts as an independent infectious agent. The antibodies against one serotype confer homotypic immunity but temporary protection against heterotypic infection. Dengue has become a growing health concern for up to one third of the world's population. Currently, there is no potent anti-dengue medicine, and treatment for severe dengue relies on intravenous fluid management and pain medications. The burden of dengue dramatically increases despite advances in vector control measures. These factors underscore the need for a vaccine. Various dengue vaccine strategies have been demonstrated, that is, live attenuated vaccine, inactivated vaccine, DNA vaccine, subunit vaccine, and viral-vector vaccines, some of which are at the stage of clinical testing. Unfortunately, the forefront candidate vaccine is less than satisfactory, and its performance depends on serostatus and age factors. The lessons from clinical studies depicted ambiguity concerning the efficacy of dengue vaccine. Our study highlighted that viral structural heterogeneity, epitope accessibility, autoimmune complications, genetic variants, genetic diversities, antigen competition, virulence variation, host-pathogen specific interaction, antibody-dependent enhancement, cross-reactive immunity among Flaviviruses, and host-susceptibility determinants not only influence infection outcomes but also hampered successful vaccine development. This review integrates dengue determinants allocated necessities and challenges, which would provide insight for universal dengue vaccine development.     

Characterization of α1-adrenoceptor subtypes mediating contractions to phenylephrine in rat thoracic aorta,mesenteric artery and pulmonary artery

1. The subtype of α₁-adrenoceptor mediating contractions to phenylephrine of the rat thoracic aorta, mesenteric artery and pulmonary artery were investigated by use of antagonists which show selectivity between the cloned α₁-adrenoceptor subtypes in binding studies.
2. Cumulative concentration-contraction curves for phenylephrine were competitively antagonized in the rat thoracic aorta by prazosin (pA₂ 9.9), WB4101 (pA₂ 9.6), 5-methylurapidil (pA₂ 8.1), benoxathian (pA₂ 9.2) and indoramin (pA₂ 7.4). These compounds were also competitive antagonists in the mesenteric and pulmonary arteries (except for 5-methylurapidil in the pulmonary artery), (prazosin pA₂ 9.9 and 9.7; WB4101 pA₂ 9.8 and 9.6; 5-methylurapidil pA₂ 7.9 and pK_B estimate 8.0; benoxathian pA₂ 8.8 and 9.3; indoramin pA₂ 7.2 and 7.5, respectively).
3. RS 17053 was not a competitive antagonist in any blood vessel as Schild plot slopes were greater than unity. The pK_B estimates for RS 17053 were 7.1 in aorta, 7.0 in the mesenteric artery and 7.7 in the pulmonary artery.
4. The α_1D-subtype selective antagonist BMY 7378 appeared to be non-competitive with shallow Schild plot slopes. The data were better fitted with two lines in all tissues, with Schild plot slopes that were no longer different from unity, except in the pulmonary artery. The higher affinity site for BMY 7378 in the aorta had a pA₂ of 9.0, while it was 8.8 and 8.9 in the mesenteric and pulmonary arteries, respectively.
5. MDL73005EF acted in a non-competitive manner in all three blood vessels, with shallow Schild plot slopes. The pK_B estimates for MDL73005EF were 8.4 in aorta, 7.5 in the mesenteric artery and 8.0 in the pulmonary artery.
6. In all three blood vessels the functionally determined antagonist affinity estimates correlated best with published pK_i values for their displacement of [³H]-prazosin binding on membranes expressing cloned α_1d-adrenoceptors compared with α_1a- or α_1b-adrenoceptors. The antagonist affinity estimates in the aorta, mesenteric and pulmonary arteries correlated highly with their previously published pA₂ values in rat aorta (α_1D) and less well with those for α_1A- and α_1B-adrenoceptors mediating contraction of the rat epididymal vas deferens and rat spleen, respectively.
7. The results of this study suggest that the contraction to phenylephrine of the rat thoracic aorta, mesenteric artery and pulmonary artery are mediated in part via the α_1D-subtype of adrenoceptor. The data for both BMY 7378 and MDL73005EF in all three blood vessels are consistent with receptor heterogeneity. However, the identity of the second site is unclear.

     

Autoregulation of nitric oxide-soluble guanylate cyclase-cyclic GMP signalling in mouse thoracic aorta

1. The sensitivity of the soluble guanylate cyclase (sGC)-cyclic guanosine-3',5'-monophosphate (cyclic GMP) system to nitric oxide (NO) was investigated in mouse aorta from wild type (WT) and NO synthase (NOS) knockout (KO) animals. 2. The NO donor, spermine-NONOate (SPER-NO) was more potent in aortas from eNOS KO mice compared to WT (pEC50 7.30+/-0.06 and 6.56+/-0.04, respectively; n=6; P<0.05). In contrast, the non-NO based sGC activator, YC-1 was equipotent in vessels from eNOS WT and KO mice. The sensitivity of aortas from nNOS and iNOS KO animals to SPER-NO was unchanged. Forskolin (an adenylate cyclase activator), was equipotent in vessels from eNOS WT and KO animals. 3. The cyclic GMP analogue, 8-Br-cGMP was equipotent in eNOS WT and KO mice (pEC50 4. 38+/-0.04 and 4.40+/-0.05, respectively; n=5; P>0.05). Zaprinast (10-5 M) a phosphodiesterase type V (PDE V) inhibitor, had no effect on the response to SPER-NO in vessels from eNOS WT or KO mice. 4. The NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 3x10-4 M) increased the potency of SPER-NO in aortas from WT mice (pEC50 6. 64+/-0.02 and 7.37+/-0.02 in the absence and presence of L-NAME, respectively; n=4; P<0.05). 5. In summary, there is increased sensitivity of vessels from eNOS KO animals to NO. Cyclic AMP-mediated dilatation is unchanged, consistent with a specific up-regulation of sGC - cyclic GMP signalling. The functional activity of cyclic GMP-dependent protein kinase (G-kinase) and PDE V was also unchanged, suggesting that sGC is the site of up-regulation. These alterations in the sensitivity of the sGC - cyclic GMP pathway might represent a mechanism for the dynamic regulation of NO bioactivity.     

Degradation Kinetics of BMP 777, an Elastase Inhibitor

Purpose. The objective was to evaluate the degradation profile of the elastase inhibitor DMP 777 and lay the foundation for formulation development. Methods. The pK_a was determined by potentiometric titration in mixed-aqueous solvents. The degradation kinetics were studied as a function of pH, buffer concentration, ionic strength, methanol concentration and temperature using a stability-indicating HPLC assay. The degradation products were identified by LC-MS, NMR, and by comparison with authentic samples. Results. The pK_a for the protonated piperazine nitrogen was estimated to be 7.04. The pH-rate profile is described by specific acid-, water-, and specific base-catalyzed pathways. The pH of maximum stability is in the range of 4 to 4.5 where water is the principal catalyst in the reaction. Buffer catalysis, primary salt effects and medium effects were observed. The proposed mechanism for acid catalyzed degradation is the rarely observed A_AL1 which involves alkyl-nitrogen heterolysis. The driving force for the reaction appears to lie in the stability of the benzylic carbocation. The proposed mechanism for base catalyzed degradation is B_AC2 which involves -lactam ring opening. The -lactam ring of DMP 777, a monolactam, appears to be as reactive as that in benzylpenicillin in the k _OH controlled region where a similar mechanism of hydrolysis should be operative. A contributing factor to this increased reactivity may lie in the reduced basicity of the -lactam nitrogen making it a good leaving group. Conclusions. The degradation profile indicates that development of a solution dosage form of DMP 777 with adequate shelf-life stability at room temperature is feasible.     

Prostate cancer old problems and new approaches

Rates of prostate cancer (PCa) have increased so dramatically over the last decade that the age adjusted incidence rate for PCa is now greater than that any other cancer among men in the United States. This review, published as a three part series, provides a state-of-art assessment of the PCa problem in its divergent aspects.Part 1 covers epidemiology, incidence and progression. Several epidemiological studies have demostrated that first degree male relatives of men with PCa are at increased risk of developing the disease. Familial and genetic factors as well as medical, anthropometric, dietary, hormonal and occupational factors involved in PCa are discussed. Postmortem examination of the prostate in men without evidence of PCa documented a high frequency of adenocarcinoma. Latent disease occurred as early as the second decade of life. Although there is no significant difference in incidence between Caucasian and African-American males, high grade prostatic intraepithelial neoplasia (HGPIN) is higher in the latter group. While dietary fat, androgens and certain environmental factors may be determinants for PCa, the exact mechanism of tumorigenesis is still relatively unknown. The current thinking of the role of genomic instability, chromosomal alterations, tumor suppressor genes and the androgen receptor are explored.