Microencapsulation of bovine spermatozoa for use in artificial insemination: a review

A technique for microencapsulation of bovine spermatozoa has been developed with minimal spermatozoal injury and thus of potential use in artificial insemination. The polymers poly-l-lysine, polyvinylamine and protamine sulfate have proven best for membranes. Encapsulation has been successful with capsules ranging in size from 0.75 to 1.5 mm, and with sperm concentrations from 45 to 180 x 10(6) cells mL-1. Successful extenders include CUE, CAPROGEN, and egg yolk-citrate-glycerol (maximum 10% v/v egg yolk for normal capsular shape). Capsule fragility (ability to rupture under ageing and physical stress) is negatively related to membrane thickness which ranges from 1.92 to 5.32 microns (depending on the concentration of polymer used) and positively related to concentration of sperm encapsulated. Heterospermic studies have shown that encapsulated sperm are capable of fertilization in vivo, but are at a disadvantage to unencapsulated sperm when cows are inseminated at conventional times. Uterine retention of inseminates is favoured by capsules having a 'sticky' membrane. Using current procedures, preliminary homospermic fertility studies indicate that sperm encapsulated with poly-l-lysine or protamine sulfate may achieve normal fertility.     

Determinants of postnatal weight in infant rhesus monkeys: implications for the study of interindividual differences in neonatal growth

This paper provides an analysis of infant body weights obtained from a sample of 38 rhesus monkey infants (Macaca mulatta) aged 29-165 days, i.e., animals still nutritionally dependent on their mothers. We examine the data on neonatal weights in relation to a number of factors, most notably, the sex of the infants, and the age and adiposity of their mothers. The infant body weights represent cross-sectional rather than longitudinal data; because they were mostly free-ranging animals, the infants were weighted just once each. Nevertheless, the results of our analysis strongly suggest that early postnatal growth in free-ranging rhesus is dependent on both maternal fatness and age. They also suggest that, although male infants are generally heavier than like-aged female infants, they do not grow any faster during the early postnatal period. Here, we speculate that the associations between infant size and both maternal age and adiposity are the result of between-mother differences in lactational output.     

Effect of acute ethanol ingestion on prolactin in menopausal women using estradiol replacement

The current study was to answer the question: Is enough mercury absorbed from dental amalgam fillings to produce renal damage? One hundred healthy adults (18-44 years old) filled out health questionnaires and voided urine samples. Urine mercury concentration and N-acetyl-beta-glucosaminidase (NAG) were measured. Subjects were grouped into those having amalgam fillings (N = 66) and those without (N = 34). Median (95% Confidence Interval) urine mercury was 1 (1-2) and 0 (0-0.6) ng/ml (P < 0.01) and median urine NAG was 23 (18-27) and 16 (11-18) units (P < 0.05) in the two groups respectively. People with mercury amalgam fillings excreted slightly more mercury than people without them, and have a very small increase in urinary NAG excretion that is probably of no clinical significance. This dose of mercury absorbed from amalgam appears to be too little to be a public health hazard for renal injury.     

Impact of clinical information systems on nursing practice. Nurses' perspectives

This article adds to the literature on the impact of computerized clinical information systems by asking nurses important questions about their nursing practices. A research tool was developed from collaborative work with clinicians who have used computers in their daily practice for more than two decades. A statewide study then was conducted on how nurses believed computer technology impacted their practice. This study also examined the different views that computer users and nonusers held. Questions were posed relating to resource consumption, nursing work practices, and professional and patient outcomes. It was found that nurses, whether computer naive or knowledgeable, clearly do not expect the technology to have negative impact on practice. The two groups differed mostly in the strength of their beliefs. One startling outcome, that slow computer response time delayed care, was identified within the computer-user group and direct action was taken as a result.     

Evaluation of hepatitis B and C viral markers: clinical significance in Asian and Caucasian patients with hepatocellular carcinoma in the United States of America

In order to evaluate the roles of hepatitis B virus (HBV) and hepatitis C virus (HCV) and their clinical significance in Asian-American and Caucasian patients with hepatocellular carcinoma (HCC) in the USA, 110 HCC patients, seen in a community-based teaching hospital in the Los Angeles area over a 10 year period, were enrolled. Seventy-nine (72%) patients were Asian-American and 31 (28%) were Caucasians. Of the 110 HCC patients, 69 (63%) were positive for serum hepatitis B surface antigen (HBsAg), 26 (24%) were positive for serum antibody to hepatitis C virus (anti-HCV), five (all Asian-Americans) were positive for both markers; 11 (10%) patients had a history of alcoholism. HBsAg was detected in 63 (80%) Asian-American patients, significantly higher than in the six (19%) Caucasian HCC patients (P < 0.01). Anti-HCV was detected in 10 (32%) Caucasian and in 16 (20%) Asian-American HCC patients (P > 0.05). Among Asian-American HCC patients, anti-HCV was more prevalent in those who were HBsAg-negative than in the HBsAg-positive patients (69 vs 8%; P < 0.01). A history of alcoholism was obtained in nine (29%) Caucasian HCC patients, significantly higher than in the two (3%) Asian-American HCC patients (P < 0.05). Comparing HCC patients with positive HBsAg and with anti-HCV, HBsAg-positive HCC patients were younger, Asian-Americans and predominantly male; 38% had a family history of liver disease. In contrast, anti-HCV-positive HCC patients were older by nearly a decade and 46% had a history of blood transfusion. Using a stepwise logistic regression analysis, Asian race and patient age < 50 years were found to be independent predictors for HBsAg-positivity, while a history of blood transfusion was the only predictor for anti-HCV-positivity in HCC patients. There was no significant difference in the rate of cirrhosis, serum levels of alpha-fetoprotein and survival between HBsAg-positive and anti-HCV-positive HCC patients. In conclusion, chronic HBV infection was the major aetiological factor in Asian-American HCC patients, while chronic HCV infection and alcoholism were major aetiological factors in Caucasian HCC patients in the USA.     

Incontinence due to an infrasphincteric ectopic ureter: why the delay in diagnosis and what the radiologist can do about it

PURPOSE: To determine (1) the reasons for the frequently long delay in the diagnosis of an infrasphincteric ectopic ureter in girls, and (2) what role the radiologist can play in decreasing the delay. MATERIALS AND METHODS: Twelve girls were referred to our hospital from June 1994 until April 1997 for evaluation of constant urinary dribbling and/or vaginal discharge. Available imaging studies, radiology reports, and clinic notes were reviewed. RESULTS: Mean age at the time of diagnosis was 6 years 7 months (range 2 years 10 months to 11 years 11 months). Mean delay until diagnosis after presentation was 2 years 5 months. Excluding the one girl whose ectopic ureter was diagnosed while she was still in diapers, mean age at the time of the first parental "complaint" was 4 years 9 months. The significance of the classic history of constant urinary dribbling was not recognized by physicians in 7 girls for 4 months to 7 years 10 months after presentation. Physical exam was not meticulously performed, as the ectopic orifice was visible in 8 of 12 girls. Imaging studies were ineffectively utilized: no imaging was done (for 2 years in 2 girls), inappropriate studies were done (ultrasound and voiding cystourethrography) and were misleading, studies were called normal when they were not (ultrasound and excretory urography), or perinatal imaging led to the incorrect assumption of a congenitally absent kidney in one girl and a multicystic dysplastic kidney in another. Excretory urography (EU) was diagnostic in all 10 girls with a duplex kidney, and computed tomography (CT) was supportive in 2 with a dysplastic kidney. CT was an adjunct in 3 girls; a Tc-99m-dimercaptosuccinic acid (DMSA) scan was needed in 2. CONCLUSION: The classic history of constant urinary dribbling in a successfully toilet-trained girl should immediately lead to an imaging search for the portion of kidney (or entire kidney) drained by an infrasphincteric ectopic ureter. EU should usually be the first imaging performed and is often the only imaging study needed.     

Some implications for quantitative risk assessment if hormesis exists

Insulin resistance is associated with hyperleptinemia, whilst exposure of hepatoma cells and isolated adipocytes to high concentrations of leptin has been demonstrated to result in attenuated insulin response and a reduced suppression of gluconeogenesis. To determine the acute metabolic effects of hyperleptinemia, we measured whole body glucose uptake (WBU) and hepatic glucose production rate (HGP) in rats using the euglycemic hyperinsulinemic clamping technique. Anesthetised male rats received recombinant murine leptin (1 microg/min) or vehicle into the jugular vein for 90 min. After 30 min of leptin infusion, insulin was infused to a level of 70 microU/ml and a variable-rate glucose infusion was adjusted to maintain blood glucose levels to 4-4.5 mmol/l. Glucose infusion rates during clamping were not different between leptin-infused and control rats, and there were no significant effects on the HPR or WBU measured using [6-(3)H]glucose under basal or clamped conditions. In summary, our data demonstrate that acute hyperleptinemia in normal weight Wistar rats does not appear to reduce insulin sensitivity, in vivo, or to affect HPR under clamp conditions.     

Ipsilateral neglect: reversal of bias or exaggerated cross-over phenomenon?

We have shown previously that plating primary cultures of rat hepatocytes under low density, which stimulates hepatocytes to shift from the G0 to the G1 phase of the cell cycle, resulted in increased levels of glutathione (GSH) and cysteine, and increased activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme in GSH synthesis (Lu et al., Am. J. Physiol. 1992;263:C1181-C1189). In the current work we examined changes in GSH homeostasis after two-thirds partial hepatectomy (PH). Male Sprague-Dawley rats underwent two-thirds PH or sham operation. GSH, oxidized glutathione (GSSG), cysteine, GSH efflux, DNA synthesis, changes in GCS subunit messenger RNA (mRNA), and protein levels were measured 12 and 24 hours after PH. Both liver GSH and cysteine levels were doubled at 12 hours and remained elevated at 24 hours after PH. GSSG levels also increased, but the ratio of GSH to GSSG levels remained unchanged. The increase in GSH and cysteine levels preceded the increase in DNA synthesis. Sinusoidal GSH efflux was unchanged after two-thirds PH, but biliary GSH efflux decreased. However, total GSH efflux was minimally altered after two-thirds PH. The increase in GSH can be largely accounted for by the increase in both cysteine availability and the activity of GCS. The steady-state mRNA and protein levels of the GCS heavy subunit were increased at 12 hours after PH. The mRNA level of the GCS light subunit was unchanged. In summary, early in the course of liver regeneration the steady-state hepatic GSH levels double because of an increase in the biosynthesis of GSH.     

Selective activation of Galphao by D2L dopamine receptors in NS20Y neuroblastoma cells

D2L dopamine receptor activation results in rapid inhibition and delayed heterologous sensitization of adenylate cyclase in several host cell types. The D2L dopamine receptor was stably transfected into NS20Y neuroblastoma cells to examine inhibition and sensitization in a neuronal cell environment and to identify the particular G-proteins involved. Acute activation of D2L receptors with the selective D2 agonist quinpirole inhibited forskolin-stimulated cAMP accumulation, whereas prolonged incubation (2 hr) with quinpirole resulted in heterologous sensitization (more than twofold) of forskolin-stimulated cAMP accumulation in NS20Y-D2L cells. To unambiguously identify the pertussis toxin (PTX)-sensitive G-proteins responsible for inhibition and sensitization, we used viral-mediated gene delivery to assess the ability of genetically engineered PTX-resistant G-proteins (Galphai1*, Galphai2*, Galphai3*, and Galphao*) to rescue both responses after PTX treatment. The expression and function of individual recombinant G-proteins was confirmed with Western blotting and inhibition of GTPgammaS-stimulated adenylate cyclase, respectively. To assess the specificity of D2L-Galpha coupling, cells were infected with herpes simplex virus (HSV) recombinants expressing individual PTX-resistant G-protein alpha subunits and treated with PTX, and quinpirole-induced responses were measured. Infection of NS20Y-D2L cells with HSV-Galphao* rescued both inhibition and sensitization in PTX-treated cells, whereas infection with HSV-Galphai1*, HSV-Galphai2*, or HSV-Galphai3* failed to rescue either response. In summary, the current study provides strong evidence that the D2L dopamine receptor couples to Galphao in neuronal cells, and that this coupling is responsible for both the acute and subacute effects of D2 receptor activation on adenylate cyclase activity.     

Importance of a conserved TCR J alpha-encoded tyrosine for T cell recognition of an HLA B27/peptide complex

Human HLA B27-restricted cytotoxic T lymphocytes (CTL) specific for the influenza A epitope NP383-391 use similar TCR alpha and beta chains, with two closely related J alpha segments used by six of nine CTL clones from three unrelated donors (Bowness et al., Eur J. Immunol. 1993. 23: 1417-1421). The role of TCR complementarity-determining region (CDR)3alpha residues 93 and 100-102 was examined by site-directed mutagenesis, following expression of the TCR alpha and beta extracellular domains from one clone as a TCR zeta fusion heterodimer in rat basophil leukemia (RBL) cells. For the first time we have measured direct binding of tetrameric HLA B*2705/NP383-391 complexes to transfected TCR. Independently peptide-pulsed antigen-presenting cells (APC) were used to induce TCR-mediated degranulation of RBL transfectants. Our results show a key role for the conserved TCRalpha CDR3 J alpha-encoded residue Y102 in recognition of HLA B27/NP383-391. Thus the Y102D mutation abolished both tetramer binding and degranulation in the presence of peptide-pulsed APC. Even the Y102F mutation, differing only by a single hydroxyl group from the native TCR, abolished detectable degranulation. Further mutations F93A and S100R also abolished recognition. Interestingly, the N101A mutation recognized HLA B27/NP in functional assays despite having significantly reduced tetramer binding, a finding consistent with "kinetic editing" models of T cell activation. Modeling of the GRb TCR CDR3alpha loop suggests that residue Y102 contacts the HLA B*2705 alpha1 helix. It is thus possible that selection of germ-line TCRAJ-encoded residues at position 102 may be MHC driven.