Prolactin secreting cells in the hypophysis of the brown spiny mouseMus platythrix (Bennett)

Prolactin secreting cells are identified in thepars distalis of Mus platythrix by conventional methods of light and electron microscopy. Two types of prolactin secreting cells are recognised. These types are estrone-sensitive, mammotrophic type I, and luteotrophic type II, respectively. Histochemical analysis revealed that the cells are rich in RNA, basic proteins, alkaline phosphatase and are resistant to extraction with 0·5% trichloroacetic acid. Quantitative data showed that the prolactin secreting cells increase during pregnancy, lactation and estrone treatment. Estrone at low dose levels caused immense hyperplasia whereas at higher levels there was no corresponding increase in the percentage of type I cells. Ultrastructurally, prolactin secreting cells are characterised by the presence of stacked endoplasmic reticulum, oval or irregular secretory granules. The Golgi apparatus is seen rich in vacuolar system.     

Hippocampal brain amines in methotrexate-induced learning and memory deficit

Intrathecal methotrexate in children with leukemia is known to cause seizures, dementia, leukoencephalopathy, and cognitive dysfunction after long-term treatment. To investigate the cognitive dysfunction, male Wistar rats were given multiple intracerebroventricular injections of methotrexate. Its effect on behaviour was tested in the two-compartment conditioned avoidance task and dark-bright arena test. Levels of brain amines in the hippocampal region of the brain were estimated by HPLC. The qualitative and quantitative histopathological changes in the different regions of the hippocampus were studied by cresyl violet staining. Multiple injections (1 or 2 mg/kg) produced convulsions and learning and memory impairment but did not induce anxiolytic activity. They also reduced concentrations of all three brain amines (norepinephrine, dopamine, and serotonin) and the serotonin metabolite 5-hydroxyindoleacetic acid. The CA4 region of the hippocampus was severely affected by intraventricular methotrexate. Disruption of brain monoamines has been proposed as a cause of brain dysfunction from this chemotherapy, and that disruption may in turn involve cytotoxic effects of methotrexate on brain tissue. The outcomes of this study may have therapeutic implications in the management of cancer conditions, particularly in childhood lymphoblastic leukemia.     

Effect of deuterium oxide on the pituitary gonadotrophs of the brown spiny mouse. Mus platythrix Bennett.

Adult individuals of M. platythrix were maintained on 30 per cent D2O by volume in drinking water at varying periods of time. Qualitative and quantitative changes in pituitary FSH and LH cells were observed. The former revealed hyperplasia and hypertrophy by 10 days attaining their peak of activity and hyalinization by 20 days. In contrast response in the LH cells was rather slow. They showed a significant increase in number after 30 days and hyalinization by 50 days. FSH cells revealed decline in activity by 50 days whereas LH cells attained their peak numerically by 40 days and underwent no change thereafter. These observations suggest that in the adult male D2O reveals: 1. hyperactive influence on the gonadotrophs, and 2. differential in FSH and LH secreting cells.     

Novel KV7 ion channel openers for the treatment of epilepsy and implications for detrusor tissue contraction

Neuronal voltage-gated potassium channels, K_V7s, are the molecular mediators of the M current and regulate membrane excitability in the central and peripheral neuronal systems. Herein, we report novel small molecule K_V7 openers that demonstrate anti-seizure activities in electroshock and pentylenetetrazol-induced seizure models without influencing Rotarod readouts in mice. The anti-seizure activity was determined to be proportional to the unbound concentration in the brain. K_V7 channels are also expressed in the bladder smooth muscle (detrusor) and activation of these channels may cause localized undesired effects. Therefore, the impact of individual K_V7 isoforms was investigated in human detrusor tissue using a panel of K_V7 openers with distinct activity profiles among K_V7 isoforms. KCNQ4 and KCNQ5 mRNA were highly expressed in detrusor tissue, yet a compound that has significantly reduced activity on homomeric K_V7.4 did not reduce detrusor contraction. This may suggest that the homomeric K_V7.4 channel plays a less significant role in bladder contraction and further investigation is needed.     

Adrenocorticotrophin secreting cells in the hypophysis of the brown spiny mouseMus platythrix (Bennett)

Adrenocorticotrophin secreting cells are identified in the hypophysis of the brown spiny mouseMus platythrix by conventional methods of light microscopy. Quantitative data showed that certain smaller acidophilic cells in thepars distalis, under conditions provoking their hypersecretion such as unilateral adrenalectomy and metopirone treatment, increase in number and size from the pre-existing corticotrophs. There is no evidence for the transmigration of these cells from the chromophobes, basophils or any other cell type. Thepars intermedia revealed two types of cells of which the type II cells are histochemically identical to adrenocorticotrophin secreting cells of thepars distalis     

Effect of ovotransferrin, protamine sulfate and EDTA combination on biofilm formation by catheter-associated bacteria

AIMS: To determine the effect of a composition comprising ovotransferrin (OT), protamine sulfate (PS) and ethylenediaminetetraacetic acid (EDTA) on biofilm formation by catheter-associated bacteria. METHODS AND RESULTS: The in vitro activity of OT, PS and EDTA alone and in combinations against biofilm formation by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis and Staphylococcus epidermidis was investigated. All the three compounds either alone or in combinations failed to inhibit the growth completely at the concentrations tested. However, the subinhibitory concentrations of three compounds in a composition showed synergistic inhibitory effect on biofilm formation by K. pneumoniae, Ps. aeruginosa and S. epidermidis. Furthermore, 79-95% reduction in Ps. aeruginosa and S. epidermidis biofilm formation was observed in a clear vinyl urinary catheter treated with the composition. CONCLUSION: The subinhibitory concentrations of OT, PS and EDTA in a composition were effective in reducing biofilm formation by catheter-associated bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that a synergistic composition-comprising non-antibiotic generally regarded as safe (GRAS) compounds such as OT, PS and EDTA may be used in the prevention of catheter-related infections.     

Oviposition preference for novel versus normal food resources in laboratory populations ofDrosophila melanogaster

Female fecundity, oviposition preference and specificity on one normal and two novel food media were assayed on four laboratory populations ofDrosophila melanogaster, revealing considerable among- and within-population variation in oviposition preference. Overall, there was a significant tendency of females to prefer novel media to their normal banana food as an oviposition substrate. Specificity in the populations was fairly high, implying that a large proportion of females tended to lay the majority of their eggs on the preferred medium. The results showed that oviposition preference for a given food medium could be affected by the alternative provided, and that, consequently, oviposition preference for a given food medium versus another cannot be predicted based upon a knowledge of what the preference for each of the two media was versus a common third medium. Specificity, on the other hand, was not significantly affected by the type of alternative food media provided in a given trial. Moreover, comparison of results from fecundity and oviposition preference assays also showed that the egg laying behaviour ofDrosophila females in response to different food media may be different in choice versus no-choice situations. Thus, a substrate on which fecundity is higher than on another, when assayed in a no-choice situation, may not be preferred over the other substrate when a choice between the two is provided to the ovipositing females. The latter two results point to possible complexity in the responses of females to various oviposition substrates based upon the overall setting of the assay, including the alternative substrates present for egg laying.