Ultrastructural observations on rabbit,hamster and mouse eggs following electrical stimulation in vitro

The fine structural changes were studied in the plasma membrane, cortical granules (CGs) and meiotic spindle of rabbit, hamster and mouse eggs in response to electrical stimulation. Eggs were collected 16 to 18 hours after HCG injection, and freed from the cumulus oophorus. They were stimulated in vitro by delivering a single monophasic square wave pulse of 150 V for 1 msec. Stimulated and unstimulated eggs were fixed for fine structural observations 1, 30 and 60 minutes after stimulation. Within one minute of stimulation the microvilli of rabbit eggs were long, branching and had bulbous ends. Umbonate protrusions were also present on their surface. By 30 minutes after stimulation the rabbit eggs lacked microvilli and the perivitelline space was filled with detached vesicles. Degenerating changes were readily noticeable in the microvilli of hamster eggs by 60 minutes. Changes were not noted in the microvilli of stimulated mouse eggs. There were markedly fewer CGs in the hamster and mouse, but not rabbit, eggs by 30 minutes after stimulation, and nearly all of them disappeared in the mouse and hamster eggs by 60 minutes. The density of the CGs in the rabbit was not altered. The meiotic spindle of hamster eggs dissipated within one minute of stimulation, however, the microtubules reappeared by 60 minutes after stimulation. Rotation of the meiotic spindle occurred in the mouse and hamster eggs by 30 minutes after stimulation. In some of the mouse eggs the spindle migrated to the center and the chromosomes were in telophase.     

The NK1-receptor antagonist NKP608 has an antidepressant-like effect in the chronic mild stress model of depression in rats

The chronic mild stress (CMS) model of depression was used to study the potential antidepressant-like activity of NKP608, a non-peptidic, specific, potent and orally active NK1 receptor antagonist. In this model, a substantial decrease in consumption of a 1% sucrose solution is observed in rats continously subjected to a variety of mild stressors. This effect can be reversed by chronic administration of various classes of antidepressant drugs. Chronic, oral treatment with NKP608 (once daily for 5 weeks) gradually reversed CMS-induced reductions in sucrose consumption and, the magnitude of this effect was comparable to that observed following administration of imipramine (10 mg/kg). The time-course of action of NKP608 in the CMS model was dose-dependent. At the dose of 0.03 mg/kg, NKP608 caused a full reversal of the CMS-induced deficit in sucrose consumption after 4 weeks of treatment (comparable to 5 weeks required for imipramine), while only 1 week of treatment was required in the group receiving the dose of 0.1 mg/kg NKP608. Lower (0.003 mg/kg) and higher (1.0 mg/kg) doses of the compound were ineffective. These results suggest that NKP608 has antidepressant-like properties in the CMS model in rats; the effect was comparable to conventional drugs, but the onset of action was faster than with the representative tricyclic antidepressant imipramine.     

Distinguishing generalized anxiety disorder, panic disorder, and mixed anxiety states in older treatment-seeking adults

Eighty treatment-seeking adults age 60 or over with panic disorder, generalized anxiety disorder, and mixed anxiety states (generalized anxiety with panic attacks, panic disorder with secondary generalized anxiety) completed a clinical assessment and battery of self report measures. Several hypotheses were tested from the domains of distinguishing symptoms, associated features, and rates of comorbidity with other disorders. Greater between- than within-group variance was found on a subset of measures suggesting that the distinction between GAD and PD is generally valid in the older adult population. Higher scores on measures of sympathetic arousal, agoraphobic avoidance, and rates of comorbid somatization disorder and alcohol dependence distinguished those with PD from those with GAD. Higher scores on measures of depression and hostility, but not trait anxiety or worry, distinguished the GAD group. Results indicate that distinguishing features of GAD and PD in older treatment-seeking adults may be fewer and slightly different from those of younger adults.     

Differentiation of Rhizomucor species on the basis of their different sensitivities to lovastatin

The opportunistic pathogens Rhizomucor pusillus and Rhizomucor miehei may be agents of frequently fatal mycotic diseases. In the present study, the susceptibilities of 27 clinical and environmental isolates of R. miehei and R. pusillus to lovastatin under different culturing conditions were investigated. Most of the R. miehei strains grew at lovastatin concentrations as high as 64 to 128 microg/ml. In contrast, the inhibitory effect of lovastatin on all of the R. pusillus strains was evident at lovastatin concentrations as low as 1 to 2 microg/ml. A simple and reliable method for species-level differentiation, based on the significantly higher sensitivity of R. pusillus to lovastatin than that of R. miehei, was elaborated. According this, on malt extract agar containing 6 mug of lovastatin/ml, R. pusillus is not able to produce colonies, while R. miehei will form compact colonies.     

Familial Association of Congenital Left Heart Abnormalities and Sustained Fetal Arrhythmia

Hypoplastic left heart syndrome (HLHS) is the most common cause of death from heart disease in the first week of life. There are reports about familial concordance by presumed morphogenetic mechanisms of abnormal embryonic blood flow with phenotypes of varying severity. The risk of having a child with a left heart lesion after a previously affected child may be as high as 5% to 12%. We present case reports from four families in which sustained fetal arrhythmia (three ectopic atrial tachycardias and one severe bradycardia due to excessive ectopic atrial beats) was demonstrated. Within these four families a close relative of the mother (a previous child, a brother, or a nephew) had severe left heart abnormality (three with HLHS and one with severe aortic valve stenosis). The association of sustained fetal arrhythmia of ectopic atrial origin and severe left heart abnormalities could be expected to occur by chance in a very low percentage of cases. We conclude that sustained fetal atrial ectopic arrhythmia is a congenital abnormality and should be considered as a risk factor for inherited congenital heart abnormalities.     

Computational simulations of mitral regurgitation quantification using the flow convergence method: Comparison of hemispheric and hemielliptic formulae

Mitral regurgitation results from the incomplete closure of the mitral valve, and the noninvasive diagnosis of this disease remains an important clinical goal. In this study, steady flow computer simulations were used to evaluate flow convergence method for flow rate estimation. The hemispheric and hemielliptic formulae were compared for accuracy in the presence of complicating factors such, as ventricular confinement, orifice shape, and aortic outflow. Results showed that in the absence of aortic outflow and ventricular confinement, there was a plateau zone where the hemispheric formula approximated the true flow rate, independent of orifice shape. However, in the presence of complicating factors such as aortic outflow and ventricular confinement, there was no clear zone where the hemispheric formula could be applied. The hemielliptic formula, however, worked in, all cases, regardless of chamber size or magnitude of aortic outflow. Therefore, application of the hemielliptic formula shold be considered in future clinical studies.