Maturation of epididymal spermatozoa in the nondomesticated guinea pigs Cavia aperea and Galea musteloides

The physiological changes occurring in spermatozoa in the male reproductive tract of 2 nondomesticated species of South American guinea pigs with different mating systems were studied. Cavia aperea, the wild ancestor of the domesticated guinea pig, has a polygynous mating system, whereas Galea musteloides exhibits promiscuous mating behavior. The epididymis of both species resembled that of the domesticated guinea pig, with a swathe of tubule convolutions (linking the 2 major parts of the organ) that was of smaller size in Cavia but not Galea. Higher relative epididymal weight was demonstrated in the promiscuous species. During their journey through the epididymis, spermatozoa from Galea developed their potential for motility expression more proximally than did those of Cavia, but motility developed into forward progression in the same region in both species. The maximal velocities exhibited by mature Cavia sperm in vitro were greater than those of Galea. Spermatozoa from Cavia were twice the length of those from Galea, they had larger heads, and the acrosomes of single sperm were more sensitive to disruption during morphological preparation. Only in Cavia did agglutination of sperm into rouleaux occur, after the potential for motility had been developed. Migration of the cytoplasmic droplet along the midpiece occurred in the same regions in both species and before agglutination in Cavia. It is suggested that the male's reproductive strategy (polygyny vs promiscuity) dictates the size of the testis and epididymis, whereas the female's reproductive physiology (induced ovulation vs cyclicity) influences the posttesticular development of sperm morphology and motility in the epididymis.     

Dietary conjugated linoleic acid mixture affects the activity of intestinal acyl coenzyme A: cholesterol acyltransferase in hamsters

The present study was designed to study the mechanisms by which dietary conjugated linoleic acids (CLA) decrease serum cholesterol. Hamsters were fed a semi-synthetic diet containing 1 g cholesterol/kg diet with or without supplementation with 20 g linoleic acid (LA) and 20 g CLA/kg diet. After 8 weeks, serum fasting total cholesterol (TC) and triacylglycerol (TG) were significantly lower in the LA-supplemented and CLA-supplemented groups compared with those of the control (CTL) hamsters. In contrast to LA, CLA significantly lowered hepatic cholesterol but it increased the level of adipose tissue cholesterol, suggesting that the hypocholesterolaemic mechanism of CLA is different from that of LA. CLA decreased the activity of intestinal acyl CoA:cholesterol acyltransferase (ACAT) whereas LA had no effect on this enzyme. Consequently, CLA supplementation increased the faecal excretion of total neutral sterols, but it had no or little effect on the faecal acidic sterols. If the ACAT is associated with cholesterol absorption, the part of mechanisms by which CLA decreases serum cholesterol may involve down-regulation of intestinal ACAT activity.     

Enhancement of manumycin A-induced apoptosis by methoxyamine in myeloid leukemia cells.

Farnesyltransferase inhibitors (FTIs) are currently under investigation for leukemia treatment. We evaluated the FTI manumycin A (manumycin) in two myeloid leukemia cell lines (U937 and HL-60). Manumycin induced nitric oxide production and apoptosis of the leukemia cells. Nitric oxide or other reactive oxygen species may induce oxidative DNA damage, and the number of apurinic sites increased after manumycin treatment, which was reversed by concurrent treatment with N-acetyl-L-cysteine. Since repair of DNA damage is important to cell survival, we hypothesized that methoxyamine, an inhibitor of base-excision repair, would enhance the antineoplastic effect of manumycin. The combination of manumycin and methoxyamine resulted in enhanced apoptosis by six criteria increased annexin V binding, release of mitochondrial cytochrome c into the cytosol, activation of caspase-9, activation of caspase-3, specific cleavage of poly-adenosyl ribose polymerase, and increase in the sub-G1 cell cycle fraction. The drug combination enhanced inhibition on the soft agar clonogenic assay and on the formazan dye cell viability assay. The effects of manumycin or manumycin plus methoxyamine on apoptosis were blocked by N-acetyl-L-cysteine, and partially by nitric oxide synthase inhibitors or scavenger of peroxide. We conclude that methoxyamine enhances manumycin-induced apoptosis in myeloid leukemia cells.     

Insulin-like molecules in Momordica charantia seeds

Decorticated Momordica charantia seeds were extracted and processed by a method which was developed originally for the purification of insect and annelid insulins. Essentially, the method entailed HCl--ethanol extraction, neutralization with NH4OH, gel filtration on Sephadex G-50, ion exchange chromatography on CM Sepharose CL-6B and desalting on Sephadex G-10. Of the seven fractions collected, three fractions were obtained with antilipolytic and lipogenic activities in isolated adipocytes and one fraction with only lipogenic activity. The data indicate that molecules with insulin-like bioactivity are present in Momordica charantia seeds.     

Electrophysiological and functional effects of the KCNQ channel blocker XE991 on murine portal vein smooth muscle cells

The effect of the KCNQ channel blockers XE991, chromanol 293B and linopirdine, was studied on voltage-dependent K+ currents in smooth muscle cells dissociated freshly from mouse portal vein (mPV) and isometric tension recordings from whole mPV. Voltage clamp experiments showed XE991 inhibited an outward current in a concentration-dependent manner with an IC50 of 5.8 microM. Block was voltage independent. Chromanol 293B and linopirdine also blocked the voltage-dependent K+ current but were less potent than XE991. At least two components--a linear (I(linear)) and an outward relaxation (I(out))--contributed to the XE991-sensitive conductance. XE991-sensitive currents were sustained at all test potentials and XE991 inhibited the enhanced holding current at -60 mV produced by bathing cells in an external solution containing 36 mM KCl. Current clamp experiments in the perforated-patch configuration showed XE991 and linopirdine depolarised the resting membrane potential and augmented the evoked response in a concentration-dependent manner. In functional experiments the spontaneous contractile activity of the mPV was increased significantly by XE991 and linopirdine. The stimulatory effect of XE991 was not affected by the presence of 4-AP, glibenclamide nor paxilline. These data provide evidence for an important role for KCNQ channels in governing cellular excitability in mPV smooth muscle cells.     

Expectation and knowledge of pregnant women undergoing first and second trimester ultrasound examination in a Chinese population

OBJECTIVE: To evaluate expectation and knowledge on obstetric ultrasound examination in the first and second trimester in a Chinese population. METHOD: A cross-sectional survey was conducted in a university obstetric clinic in Hong Kong. Chinese pregnant women who underwent the first trimester early scan sessions, or the second trimester anomaly scan sessions were invited to complete a self-administered questionnaire, which contained items on their knowledge, expectation, and sociodemographic characteristics. RESULTS: In all 276 eligible pregnant women (117 in the first trimester and 159 in the second trimester) were recruited. Although 249 women (90.2%) claimed they understood the indication of the ultrasound examination, only 93 of them were correct (33.7%). The median perceived overall-detection rate for structural abnormalities was 66.5%. Living in Hong Kong for more than 7 years was significantly associated with higher knowledge level and expectation from ultrasound examination. Attaining tertiary education level was also significantly associated with higher knowledge level. Over 90% of the pregnant women studied wished to know the fetal gender from the anomaly scan examination. CONCLUSION: Knowledge of Chinese pregnant women on ultrasound was generally unsatisfactory. Understanding their limitation of knowledge and expectations helps to devise appropriate education in the local setting.