Macrophylloside, a flavone glucoside from Primula macrophylla

A new flavone glucoside macrophylloside has been isolated from the whole plant of Primula macrophylla and its structure was determined by spectroscopic methods as 2′-hydroxy-7-O-β- -glucopyranosyloxyflavone. Sitosterol glucoside was also isolated for the first time from this plant.     

The Effect of Chilling of the Physiological and Simulated Apex of 2- and 3-leaf Plants of Pisum sativum L. cv. Alaska on Lateral Shoot Growth, C-14 IAA Movement and P-32 Accumulation

The apex of a 3-leaf pea plant was chilled in cold chambers maintained at 5–7°C. The lateral shoots 1 through 5 grew, and shoot 5 eventually dominated other lateral shoots. The apex when returned to the ambient temperature did not reimpose apical dominance. The growing lateral shoots competed with the stem apex. The apices of 2- and 3-leaf plants were chilled and P-32 distribution in these plants was studied in the entire plant, at various intervals of time. Phosphorus-32 accumulation followed the growth pattern of the plant. The lateral shoots accumulated P-32 activity and very little activity was accumulated by the apex. The dominating shoots 2 and 5 accumulated the maximum amount of activity in 2- and 3-leaf plants, respectively. Labeled-IAA moved basipetally through the stem when applied to the cut stump simulating the apex. By cold treatment the translocation of IAA was influenced more than its absorption. The plant seems to metabolize this compound in the later periods of application. The plant now becomes “insensitive” to auxin and the lateral shoots grow.     

Stereoselective hydroxylation at the aliphatic carbons of 7,8- and 9,10-dihydrobenzo[a]pyrenes by rat liver microsomes

Optically active 7-hydroxy-7,8-dihydrobenzo[a]pyrene and 8-hydroxy-7,8-dihydrobenzo[a]pyrene were identified as two of the major metabolites formed by incubation of 7,8-dihydrobenzo[a]pyrene with rat liver microsomes. Optically active 9-hydroxy-9,10-dihydrobenzo[a]pyrene and 10-hydroxy-9,10-dihydrobenzo[a]pyrene were similarly identified as two of the minor metabolites of 9,10-dihydrobenzo[a]pyrene. The formation of these metabolites was abolished either by prior treatment of liver microsomes with carbon monoxide or the absence of NADPH, but was not inhibited by an epoxide hydrolase inhibitor. The results indicate that the aliphatic carbons of dihydro polycyclic aromatic hydrocarbons may undergo stereoselective hydroxylation reactions catalyzed by the cytochrome P-450 system of rat liver microsomes.     

Antifungal effect of Penicillium metabolites against some fungi

Microorganisms are increasingly exploited as a source of new biological control agents. Genus Penicillium is a source of novel bioactive molecules which can be used as antifungal agents. The objective of this study was to evaluate the antifungal potential of Penicillium strains. Culture filtrates of two Penicillium species were tested for their antifungal potential by well diffusion assays. Filtrate of Penicillium isolates showed high antifungal effects on mycelial growth of Fusarium oxysporum, Fusarium solani, Macrophomina phaseolina, Aspergillus japonicus var aculeatus and Cladosporium cladosporioides. But Penicillium italicum inhibit the fungal growth from 45 to 68% as compared to Penicillium simplissimum (25–68%). However in case of A. japonicus var aculeatus, Penicillium spp. extracts were equally effective and reduce the colony growth up to 68%. However, P. simplissimum extract was least effective in case of M. phaseolina, where it decreased the colony growth only 25%.     

A case of primary amenorrhea with 46+XY genotype from Kashmir Valley

Primary amenorrhea is one of the common reproductive disorder affecting females. It leads to the absence of menarche in the reproductive age group in females and/or complete absence of reproductive organs. There are many causes which lead to PA, including genetic aberrations which are the leading factors.     

Utility of Dexrazoxane for the Attenuation of Epirubicin-Induced Genetic Alterations in Mouse Germ Cells

Dexrazoxane has been approved to treat anthracycline-induced cardiomyopathy and extravasation. However, the effect of dexrazoxane on epirubicin-induced genetic alterations in germ cells has not yet been reported. Thus, the aim of this study was to determine whether dexrazoxane modulates epirubicin-induced genetic damage in the germ cells of male mice. Our results show that dexrazoxane was not genotoxic at the tested doses. Furthermore, it protected mouse germ cells against epirubicin-induced genetic alterations as detected by the reduction in disomic and diploid sperm, spermatogonial chromosomal aberrations, and abnormal sperm heads. The attenuating effect of dexrazoxane was greater at higher dose, indicating a dose-dependent effect. Moreover, sperm motility and count were ameliorated by dexrazoxane pretreatment. Epirubicin induced marked biochemical changes characteristic of oxidative DNA damage including elevated 8-hydroxy-2ʹ-deoxyguanosine levels and reduction in reduced glutathione. Pretreatment of mice with dexrazoxane before epirubicin challenge restored these altered endpoints. We conclude that dexrazoxane may efficiently mitigate the epirubicin insult in male germ cells, and prevent the enhanced risk of abnormal reproductive outcomes and associated health risks. Thus, pretreating patients with dexrazoxane prior to epirubicin may efficiently preserve not only sperm quality but also prevent the transmission of genetic damage to future generations.     

Assessment of platelet function in patients with stroke using multiple electrode platelet aggregometry: a prospective observational study

The Qatari law, as in many other countries, uses brain death as the main criteria for organ donation and cessation of medical support. By contrast, most of the public in Qatar do not agree with the limitation or withdrawal of medical care until the time of cardiac death. The current study aims to examine the duration of somatic survival after brain death, organ donation rate in brain-dead patients as well as review the underlying etiologies and level of support provided in the state of Qatar. This is a retrospective study of all patients diagnosed with brain death over a 10-year period conducted at the largest tertiary center in Qatar (Hamad General Hospital). Among the 53 patients who were diagnosed with brain death during the study period, the median and mean somatic survivals of brain-dead patients in the current study were 3 and 4.5 days respectively. The most common etiology was intracranial hemorrhage (45.3%) followed by ischemic stroke (17%). Ischemic stroke patients had a median survival of 11 days. Organ donation was accepted by only two families (6.6%) of the 30 brain dead patients deemed suitable for organ donation. The average somatic survival of brain-dead patients is less than one week irrespective of supportive measures provided. Organ donation rate was extremely low among brain-dead patients in Qatar. Improved public education may lead to significant improvement in resource utilization as well as organ transplant donors and should be a major target area of future health care policies.     

The structure of arylamine N-acetyltransferase from Mycobacterium smegmatis--an enzyme which inactivates the anti-tubercular drug,isoniazid

Arylamine N-acetyltransferases which acetylate and inactivate isoniazid, an anti-tubercular drug, are found in mycobacteria including Mycobacterium smegmatis and Mycobacterium tuberculosis. We have solved the structure of arylamine N-acetyltransferase from M. smegmatis at a resolution of 1.7 A as a model for the highly homologous NAT from M. tuberculosis. The fold closely resembles that of NAT from Salmonella typhimurium, with a common catalytic triad and domain structure that is similar to certain cysteine proteases. The detailed geometry of the catalytic triad is typical of enzymes which use primary alcohols or thiols as activated nucleophiles. Thermal mobility and structural variations identify parts of NAT which might undergo conformational changes during catalysis. Sequence conservation among eubacterial NATs is restricted to structural residues of the protein core, as well as the active site and a hinge that connects the first two domains of the NAT structure. The structure of M. smegmatis NAT provides a template for modelling the structure of the M. tuberculosis enzyme and for structure-based ligand design as an approach to designing anti-TB drugs.     

Antigen-specific CD8+ T cell clonal expansions develop from memory T cell pools established by acute respiratory virus infections

Increasing age is associated with the development of CD8+ T cell clonal expansions (TCE) that can dominate the peripheral T cell repertoire and interfere with immune responses to infection and vaccination. Some TCE are driven by chronic infections, consistent with dysregulated outgrowth of T cell clones in response to persistent antigenic stimulation. However, a second class of TCE develops with age in the absence of chronic infections and is poorly understood in terms of origin or Ag dependence. In this study, we present evidence that Ag-specific TCE develop at high frequencies from conventional memory CD8+ T cell pools elicited by nonpersistent influenza and parainfluenza virus infections. Putative TCE occurred in both the central- and effector-memory CD8+ T cell populations and did not require Ag for their maintenance. In addition, they were similar to normal memory T cells in terms of phenotype and function, suggesting that they develop stochastically from the memory T cell pool. These data suggest that memory T cell pools become progressively dysregulated over time and this may have a significant impact on immune responsiveness in the aged.