Declining age of menarche in West Bengal

A steady fall in menarcheal age has been observed in many countries during this century. A study on 894 school girls of different parts of West Bengal was carried out by recollection method to verify whether the decline in menarcheal age is existing in West Bengal or not. Evidence of steady fall of menarcheal age has been confirmed in the present study.     

Characterization of solid-state forms of celecoxib.

This study deals with the generation and characterization of various solid-state forms of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor. The drug was subjected to polymorphic screen using different solvents to explore the possibility of existence of different solid forms. N,N-Dimethyl acetamide (DMA) and N,N-dimethyl formamide (DMF) yielded solvates in 1:1 stoichiometric ratio. Quench cooling of the melt resulted in amorphous form of the drug. All these solid-state forms were characterized by thermoanalytical (DSC, TGA, HSM), crystallographic (XRD), microscopic (polarized, SEM), spectroscopic (FTIR), and elemental analysis techniques. Solubility and van't Hoff studies were carried out for their thermodynamic interpretation. Influence of morphology of different solid-state forms on flow behavior was also investigated. Molecular modeling studies were used to elucidate the interaction between solute and solvent molecules in the solvate.     

Oxidant-mediated activation of cytosolic phospholipase a(2) in pulmonary endothelium: role of protein kinase C alpha and a pertussis toxin-sensitive protein.

The authors have previously demonstrated that the oxidant t-buOOH stimulates phospholipase A(2) (PLA(2)) activity in bovine pulmonary artery endothelial cells (S. Chakraborti et al. American Journal of Physiology, 257, L430-L437, 1989). Herein, the authors sought to investigate the mechanism by which t-buOOH stimulates PLA(2) activity and the role of protein kinase C (PKC) in this scenario. Treatment of bovine pulmonary artery endothelial cells with t-buOOH stimulated an aprotinin-sensitive protease activity, PKC activity, and PLA(2) activity in the cell membrane. Pretreatment with intracellular Ca(2+) chelator (BAPTA-AM), PKCalpha inhibitor (Go6976), cPLA(2) inhibitor (AACOCF(3)), and pertussis toxin prevented t-buOOH-stimulated PLA(2) activity. Immunoblot studies with aprotinin, cPLA(2), PKCalpha, and Gialpha antibodies revealed their presence in the endothelial membrane. Immunoblot studies of the cell membrane isolated from t-buOOH-stimulated cells with cPLA(2) and PKCalpha antibodies elicited an apparent increase in their immunoreactive protein profiles along with an additional 47-kDa immunoreactive fragment in the membrane. t-buOOH caused Gialpha phosphorylation in the membrane and pretreatment with Go6976 prevented the phosphorylation. Overall, these results suggest that t-buOOH stimulates an aprotinin-sensitive protease activity that proteolytically activates PKCalpha and that subsequently phosphorylates a pertussis toxin-sensitive protein, resulting in the stimulation of cPLA(2) activity in the cell membrane.     

Cell membrane-associated MT1-MMP-dependent activation of pro-MMP-2 in A375 melanoma cells.

Matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases, can degrade extracellular matrix components under physiological conditions and during cancer invasion and metastasis. Among the MMPs, the 72 kDa type IV collagenase MMP-2 (gelatinase A) is activated in a membrane-associated manner by an activation complex composed of membrane type 1 matrix metalloproteinase (MT1-MMP), tissue inhibitor of matrixmetalloproteinase-2 (TIMP-2), and pro-MMP-2 in the presence of alphavbeta3 integrin receptor. The activation of pro-MMP-2 correlates with increased occurrence of metastases. Increased MMP-2 activity has been demonstrated in many human tumors. In the present communication, we studied cell surface-associated activation of MMP-2 (72 kDa collagenase type IV) in the moderately metastatic human melanoma cell line A375. RESULTS: Activation of purified 72 kDa collagenase type IV, pro-MMP-2 from cervical cancer tissue homogenate and from serum-free culture medium of HT1080 cells grown in presence of concanavalin A, by A375 cells, was shown by gelatin zymography. A375 cells activated only pro-MMP-2 from purified MMP-9/MMP-2 mixture indicating that the activation is specific for MMP-2. Activation of MMP-2 and purified collagenase type IV by A375 membrane fraction and membrane extract was also demonstrated by gelatin zymography. When A375 cells were first incubated with anti-MT1-MMP polyclonal antibody, activation of collagenase type IV was significantly decreased, indicating that membrane-associated MMP-2 activation is MT1-MMP-mediated. Immunocytochemistry showed MT1-MMP localization at focal adhesion sites. The presence of the components of activation complex-MT1-MMP and integrin alphavbeta3-were confirmed by Western blot, cell adhesion assay, and integrin subunit assay. CONCLUSION: Our experimental findings furnish another example of the unique membrane-associated MMP-2 activation mechanism in A375 melanoma cells and clearly indicate the role of MT1-MMP in MMP-2 activation. The information could help in developing new therapies designed to interfere with MMP activation and management of cancer and metastases.     

Role of a second stage partogram in predicting the outcome of normal labour

Background: Management of the second stage of labour is dictated by arbitrary time limits rather than true measures of progress. No partogram is available for second stage of labour.
Objectives: To evaluate a partogram designed for use for the second stage of labour.
Methods: This prospective cross-sectional analytical study included low-risk pregnant women with singleton fetuses with vertex presentations at term. From onset of the second stage, vaginal examinations were performed every 30 min until delivery. A scoring system developed by Sizer et al . was used based on station and position of fetal head. Scores were plotted on a second stage partogram and used to predict labour outcomes, such as duration of second stage and mode of delivery.
Results: Of 79 women examined, 73 had spontaneous vaginal delivery. Of the remaining six, four required oxytocin infusion and other two required vacuum extraction. The median durations of the second stage of labour for primigravidas ( n  = 34) and multigravidas ( n  = 45) were 35 and 25 min, respectively. The median Sizer's partogram score at the onset of second stage was 4. Multiple regression analysis showed that the partogram score ( r ² = 0.27) and gravidity ( r ² = 0.10) were independent predictors of duration of the second stage. There was a significant association between second stage progress plotted to the right of the partogram line and non-spontaneous delivery ( P =  0.01).
Conclusion: The second stage partogram score at onset can predict the duration of second stage. Poor progress plotted on the partogram is associated with non-spontaneous delivery.     

Pituicytoma: Report of three cases with review of literature

Pituicytoma is a rare low-grade tumor (WHO Grade I) of pituicytes involving the sellar–suprasellar region, and originating from the specialized glial cells of the neurohypophysis. Clinically and radiologically, they closely mimic pituitary adenoma or meningioma. Diagnosis requires histopathological examination of the resected tissue. This uncommon glial neoplasm is a rarity, with only 57 cases reported in the literature so far. We report three cases of pituicytoma (aged between 7 and 24 years) presenting with reduced vision, headache and features of hypercortisolism in one case. Radiologically, these lesions mimicked meningioma, hypothalamic chiasmatic glioma and pituitary microadenoma, respectively. The second case is a 7-year-old girl, the youngest case on record. Since this tumor is uncommon, it is frequently misdiagnosed. Awareness of this entity is essential for planning management and treatment. We present a brief review of all cases reported in the medical literature, and describe the clinical symptomatology, associated endocrinological abnormalities, imaging characteristics, behavior and outcome.     

Relationship between Medical School Diversity and Participation in the US News and World Report Survey

IntroductionReporting in USNWR rankings may reveal unintended, but important, sources of disparities with implications for medical school admissions and the future physician workforce.Materials and methodsTo investigate relationships between allopathic medical school's student body diversity and participation in the US News and World Report Survey, we analyzed diversity statistics as listed in the Medical School Admissions Requirements (MSAR) database. These were compared to the institution's participation in the US News and World Report Survey for 152 US medical schools as either Primary Care or Research ranking.Results & DiscussionWhen considering USNWR rankings of research schools of medicine, those schools not participating in the survey had a 44.8% increase in UIM students. There was a statistical increase in the percentage of Latino/Hispanic students in schools that did not participate in the US News and World report survey as compared with those that did. Percentages of African American and Latino/Hispanic students were inversely correlated with US News and World Report research rankings. We suggest that participation in current publicly available allopathic medical school ranking platforms may have unintended and adverse consequences in maintaining a diverse medical school class and may impact longer-term goal of developing a diverse physician workforce that resembles the constituent population.     

Extracellular superoxide dismutase is important for hippocampal neurogenesis and preservation of cognitive functions after irradiation

Cranial irradiation is widely used in cancer therapy, but it often causes cognitive defects in cancer survivors. Oxidative stress is considered a major cause of tissue injury from irradiation. However, in an earlier study mice deficient in the antioxidant enzyme extracellular superoxide dismutase (EC-SOD KO) showed reduced sensitivity to radiation-induced defects in hippocampal functions. To further dissect the role of EC-SOD in neurogenesis and in response to irradiation, we generated a bigenic EC-SOD mouse model (OE mice) that expressed high levels of EC-SOD in mature neurons in an otherwise EC-SOD–deficient environment. EC-SOD deficiency was associated with reduced progenitor cell proliferation in the subgranular zone of dentate gyrus in KO and OE mice. However, high levels of EC-SOD in the granule cell layer supported normal maturation of newborn neurons in OE mice. Following irradiation, wild-type mice showed reduced hippocampal neurogenesis, reduced dendritic spine densities, and defects in cognitive functions. OE and KO mice, on the other hand, were largely unaffected, and the mice performed normally in neurocognitive tests. Although the resulting hippocampal-related functions were similar in OE and KO mice following cranial irradiation, molecular analyses suggested that they may be governed by different mechanisms: whereas neurotrophic factors may influence radiation responses in OE mice, dendritic maintenance may be important in the KO environment. Taken together, our data suggest that EC-SOD plays an important role in all stages of hippocampal neurogenesis and its associated cognitive functions, and that high-level EC-SOD may provide protection against irradiation-related defects in hippocampal functions.Cranial irradiation is widely used as a treatment modality for patients with primary or metastatic brain tumors (1–3), and is also used as a prophylactic treatment to prevent metastases of high-risk tumors to the nervous system (4). Although effective, cranial irradiation is associated with various complications or side effects in cancer survivors (1–3). One of the severe complications is neurocognitive impairment, which can include defects in executive functions and learning and memory (3). Neurocognitive impairments occur in both adults and children and are generally associated with higher doses and younger age (3). The pathogenesis of radiation-induced neurocognitive impairment is not completely understood, but recent studies suggest that suppressed hippocampal neurogenesis (5, 6), increased hippocampal neuronal apoptosis (7, 8), and reduced growth hormone secretion (9, 10) may be involved.The production of reactive oxygen species (ROS) is considered a major cause of radiation-induced tissue damage (11). Ionizing irradiation not only results in the acute generation of short-lived ROS, it also results in a persistent state of oxidative stress that extends up to several months or even years after irradiation (12, 13). Accordingly, animal and cell models with altered antioxidant capacities have been used to investigate the biochemical pathways involved in radiation-induced tissue and cell injuries, and experimental antioxidant-based therapies have been designed to protect normal tissues during radiation treatments (14).Hippocampal neurogenesis is important for hippocampal-dependent functions of learning and memory and the process is exquisitely sensitive to suppression by various stressors, including radiation and oxidative stress (5, 6, 15). To determine if altered redox balance in the hippocampal microenvironment affects hippocampal neurogenesis and the associated functions of learning and memory, we used a knockout mouse model (KO) deficient in the extracellular antioxidant enzyme, EC-superoxide dismutase (EC-SOD), in an earlier study with cranial irradiation (13, 16). When examined at 3–4 mo of age, EC-SOD deficiency was associated with a significant suppression of baseline neurogenesis and impaired hippocampal-dependent cognitive functions (13, 16). Unexpectedly, EC-SOD deficiency also rendered the process less sensitive to radiation-induced changes. The underlining mechanism for this paradoxical finding was not clear, but preliminary studies ruled out up-regulation of major antioxidant enzymes (13). The results suggested that the interaction between redox balance and irradiation and their effects on hippocampal functions can be complex, and understanding how these elements work in concert may be a key to identifying strategies for radioprotection.To manipulate redox balance in the hippocampus, we generated a mouse model with inducible EC-SOD transgenes (17). In the current study, we combined the inducible transgenes with EC-SOD KO and generated a bigenic mouse model, designated as the overexpressor (OE), with high levels of EC-SOD expressed only in Ca/calmodulin-dependent protein kinase- (CaMKII) positive neurons in an otherwise EC-SOD–deficient environment (17). Hippocampal neurogenesis generates new granule cells that are functionally integrated into the hippocampal network (18). Because granule cells are CaMKII-positive neurons and are the principal excitatory neurons in the dentate gyrus, the manipulation leads to an estimated four- to fivefold increase in EC-SOD activity in the hippocampal formation in OE mice (17). The OE mice were used to investigate the effects of altered EC-SOD levels at different stages of hippocampal neurogenesis and the functional consequences of learning and memory. Comparison between WT, OE, and KO mice revealed the importance of EC-SOD in progenitor cell proliferation, dendritic development, and long-term survival of newborn neurons. The study results also suggested that maintenance of the dendritic system following cranial irradiation was important for preservation of neurocognitive functions.     

Activation of erythropoietin receptors by Friend viral gp55 and by erythropoietin and down-modulation by the murine Fv-2r resistance gene.

The leukemogenic membrane glycoprotein (gp55) encoded by Friend spleen focus-forming virus appears to bind to erythropoietin receptors (EpoR) sto stimulate erythroblastosis [Li, J.-P., D'Andrea, A.D., Lodish, H.F. & Baltimore, D. (1990) Nature (London) 343, 762-764]. To directly compare the effects of gp55 with erythropoietin (Epo), we produced retrovirions that encode either gp55, Epo, or EpoR. After infection with EpoR virus, interleukin 3-dependent DA-3 cells bound 125I-labeled Epo and grew without interleukin 3 in the presence of Epo. These latter cells, but not parental DA-3 cells, became factor-independent after superinfection either with Epo virus or with Friend spleen focus-forming virus. In addition, Epo virus caused a disease in mice that mimicked Friend erythroleukemia. Although Fv-2r homozygotes are susceptible to all other retroviral diseases, they are resistant to both Epo viral and Friend viral erythroleukemias. These results indicate that both gp55 and Epo stimulate EpoR and that the Fv-2 gene encodes a protein that controls response to these ligands. However, the Fv-2 protein is not EpoR because the corresponding genes map to opposite ends of mouse chromosome 9. These results have important implications for understanding signal transduction by EpoR and the role of host genetic variation in controlling susceptibility to an oncogenic protein.