Molecular characterisation of ovarian cathepsin D in the rainbow trout, Oncorhynchus mykiss

In fish, cathepsin D, an aspartyl protease, is believed to mediate the processing of yolk proteins in the oocyte. Cathepsin D, therefore, is vital for the production of a viable egg. This study set out to isolate and sequence the cDNA encoding cathepsin D, and to determine the developmental expression of the message in the ovary and subsequently during embryogenesis in the rainbow trout, Oncorhynchus mykiss. The full-length trout cathepsin D cDNA is 1847 base pairs (bp) long, encoding a protein of 400 amino acids (aa). The sequence consists of a putative signal peptide of 18 aa, a prosequence extending 46 aa and a mature peptide of 336 aa. The deduced sequence of rainbow trout ovarian cathepsin D shows significant homology with cathepsin D in mammals (human; 81% aa similarity), in the chicken (80% aa similarity) and in Xenopus (74% aa similarity). Our data support the contention that the primary structure of cathepsin D is highly conserved across the vertebrate phyla, from mammals to fish. Unlike cathepsin Ds in other species, however, rainbow trout cathepsin D appears to have only one putative N-glycosylation site, rather than two. The mRNA for 'ovarian' cathepsin D was expressed in both ovarian and non-ovarian tissues (liver, muscle, spleen and testis). During the development of the ovary, the highest expression levels of cathepsin D mRNA were seen at around the onset of vitellogenesis, a time when the oocytes are starting to sequester large quantities of yolk proteins. Northern hybridisation did not detect cathepsin D mRNA in either unfertilised eggs, or in fertilised eggs until after gastrulation, indicating that there is little, if any, de novo synthesis of this message at these stages of development. However, the mRNA for cathepsin D was detectable at the eyed embryo stage, and the expression of the gene increased towards the end of embryonic development.

Interleukin-1 beta inhibits phospholamban gene expression in cultured cardiomyocytes

Phospholamban is a key regulatory protein that defines diastolic function. Proinflammatory cytokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) can depress contractility and intracellular Ca2+ currents and transients. An alteration in phospholamban expression is a possible pathway by which these cytokines modulate cardiac function. To test this hypothesis, primary cultures of neonatal rat cardiomyocytes were incubated with IL-1 beta, TNF-alpha, or both, and the level of phospholamban transcripts was examined by Northern blot analyses. Phospholamban transcript levels were decreased approximately equal to 50% (P < .0001) in cells exposed to 2 ng/mL IL-1 beta (20 hours), whereas TNF-alpha had no effect. Western blot analyses showed that IL-1 beta also reduced phospholamban protein levels (60% of control, P < .0001). The effects on transcript levels were gene specific; IL-1 beta induced transcripts for inducible NO synthase (iNOS), did not alter GAPDH transcripts, and reduced sarcoplasmic reticulum Ca(2+)-ATPase (65% of control, P < .001) transcripts. Cardiomyocytes treated with IL-1 beta showed no alterations in basal contractile parameters (maximum velocity of contraction and relaxation and maximal amplitude of contraction) but were unresponsive to beta-adrenergic stimulation. Studies performed in the presence of second-messenger inhibitors showed that the effect of IL-1 beta on phospholamban transcript levels was blocked by dexamethasone, was insensitive to inhibitors of iNOS, cyclooxygenase, or tyrosine kinases, but was enhanced by the addition of the protein kinase inhibitor staurosporine. These data demonstrate that IL-1 beta alters the expression of phospholamban, a key regulator of cardiac contractility, at both the transcript and protein levels. The results suggest novel mechanisms by which IL-1 beta may modify cardiac function.

A simple monoclonal antibody based ELISA for free protein S. Comparison with PEG precipitation

A simple monoclonal antibody based ELISA for free Protein S, compatible with out existing ELISA for total Protein S has been developed, and its performance compared with the conventional PEG precipitation method of free Protein S assay. The normal range (mean +/- 2 SD) was 0.19-0.54 iu/ml free Protein S. The mean intra assay variation was 5.24% and the mean inter assay variation was 5.50%. A total of 102 routine diagnostic samples from patients referred for prothrombotic investigation (six assays for each method) were assayed by PEG precipitation (mean 0.32 iu/ml, SD 10.60), and the monoclonal ELISA (mean 0.34, SD 0.9). Paired t-test analysis of the two data sets indicated no significant difference between them (P < 0.001). In this sample population, there was no significant difference in free Protein S values when assayed by monoclonal based ELISA or by PEG precipitation. The monoclonal assay has proved to be reliable, accurate and precise. The monoclonal ELISA is simpler, quicker and easier to perform in routine use. Data generated is directly comparable to that generated by PEG precipitation. This methodology would be suitable for laboratories currently measuring Protein S by ELISA.

A mixed foodborne outbreak with Salmonella heidelberg and Campylobacter jejuni in a nursing home

OBJECTIVE

To investigate a mixed Salmonella heidelberg and Campylobacter jejuni foodborne outbreak in a nursing home.

DESIGN

Retrospective cohort study with a nested case-control design. Cases were defined by positive stool-culture results. Controls needed to be both asymptomatic and culture-negative.

SETTING AND PATIENTS

Residents of a 580-bed nursing home in Brooklyn, New York.

RESULTS

Of the 580 residents, 119 (21%) developed illness. Of the 93 symptomatic patients who submitted specimens, cultures were positive for S heidelberg in 24 (26%), C jejuni in 14 (15%), and both microorganisms in 25 (27%). Only the pureed diet was associated highly with infection by either Salmonella (odds ratio [OR], 17.6; 95% confidence interval [CI95], 4.8-68.7; P < .001), Campylobacter (OR, 13.3; CI95, 3.2-59.2; P < .001), or both organisms (OR, 8.9; CI95, 2.7-30.3; P < .001). Among the 42 pureed foods served during the 5 days before the outbreak, five meat or poultry items were associated most strongly with culture positivity. Of these five meat items, only a chopped-liver salad was implicated by the two employees reporting illness. A reported food-handling error occurred when ground, cooked chicken livers were placed in a bowl containing raw chicken-liver juices.

INTERVENTION

Recommendations for proper cleaning and sanitizing of kitchen equipment to prevent cross-contamination between raw and cooked foods.

CONCLUSIONS

Mixed foodborne outbreaks occur rarely. During this outbreak, contamination of a single food item with multiple bacterial pathogens was the likely source of transmission. Improper food-handling techniques that promote growth of one microorganism also allow growth of other pathogens that may be present. Because different sources and routes of transmission may be implicated for different pathogens, specific preventive measures may vary depending on the organisms involved.

Measles vaccination levels of children enrolled in WIC during the 1991 measles epidemic in New York City

OBJECTIVES

This study assessed measles vaccination rates and risk factors for lack of vaccination among preschool children enrolled in the Special Supplemental Food Program for Women, Infants, and Children (WIC) during the 1991 measles epidemic in New York City.

METHODS

Children aged 12 to 59 months presenting for WIC certification between April 1 and September 30, 1991, at six volunteer WIC sites in New York City were surveyed.

RESULTS

Of the 6181 children enrolled in the study, measles immunization status was ascertained for 6074 (98%). Overall measles coverage was 86% (95% confidence interval [CI] = +/- 1%) and at least 90% by 21 months of age (95% CI = +/- 1%). Young age of the child, use of a private provider, and Medicaid as a source of health care payment were risk factors for lack of vaccination (P < .001).

CONCLUSIONS

During the peak of a measles epidemic, measles immunization rates were more than 80% by 24 months of age in a sample of WIC children. The ease of ascertaining immunization status and the size of the total WIC population underscore the importance of WIC immunization initiatives.

Motor actions of eliprodil in the normal and monoamine-depleted mouse: a role in the treatment of Parkinson's disease?

The non-competitive NMDA polyamine site antagonist, eliprodil, was examined for its effects on exploratory activity in non-habituated mice and for its antiakinetic potential in reserpine-treated mice. A low dose of eliprodil (5 mg/kg) weakly stimulated locomotion in naive animals, whilst higher doses depressed rearing (20-40 mg/kg) and grooming (40 mg/kg), consistent with a sedative action. At no dose did eliprodil cause ataxia. In 24 h reserpine-treated mice, eliprodil (10-40 mg/kg) reversed akinesia, but this effect was subject to considerable inter-animal variation and was not statistically significant. Eliprodil did not alter the motor recovery elicited by the dopamine D1 agonist SKF 38393, or the dopamine D2 agonist RU 24213, and suppressed the motor stimulation induced by L-DOPA. These results indicate that eliprodil displays a far lower propensity than many other NMDA receptor antagonists for disturbing posture and gait, but lacks the essential motor stimulant action required to make it a safe and effective antiparkinsonian agent, at least in the reserpine-treated mouse model of Parkinson's disease.

Is fasting necessary before prilocaine Bier's block?

OBJECTIVE

To determine whether fasting is necessary before intravenous regional anaesthesia (Bier's block).

METHODS

A questionnaire study was carried out to assess accident and emergency (A&E) departments' policies and opinions in relation to Bier's block anaesthesia. Questionnaires were sent to 282 A&E consultants, of whom 216 replied (77% response rate).

RESULTS

About 5000 Bier's block procedures are carried out each year in the United Kingdom. Intravenous regional anaesthesia appears safe. Over one third of units did not fast their patients. The complication rate was similar in fasted and unfasted groups.

CONCLUSIONS

Starvation of the patient before intravenous regional anaesthesia is not necessary and should be abandoned.

Mechanisms controlling egg size and number in the rainbow trout, Oncorhynchus mykiss

Female rainbow trout (Oncorhynchus mykiss) produce a single batch of eggs each year; synchronous growth of oocytes, all of which are ovulated at the same time, occurs in the two ovaries. To examine the regulatory mechanisms controlling egg size and number, virgin female rainbow trout were subjected to unilateral ovariectomy (ULO) during early vitellogenesis, and oocyte recruitment and growth in the remaining ovary were monitored. The study also set out to determine whether the presence of a second population of smaller oocytes in the maturing pool (induced by ULO) affected the timing of ovulation and/or the size of the eggs ovulated. Two months after ULO, there was no difference in the gonadosomatic index between ULO fish and controls. Compensatory ovarian hypertrophy resulted from the recruitment of a second population of primary oocytes into the vitellogenic pool. This population of smaller maturing oocytes in the ULO fish displayed growth rates up to twice those of the population of larger oocytes in the same ovary and of oocytes in controls. The growth rate of the population of larger oocytes in the ULO fish was not altered by the recruitment of a second maturing population. One month after ULO, fish had a lower concentration of plasma estradiol-17 beta than did controls; subsequently the concentrations of plasma estradiol-17 beta in the ULO and control groups were similar. After ULO, plasma levels of vitellogenin in the ULO fish did not differ from those in the control group throughout the study. At or close to ovulation, the fecundity of ULO fish was 75-80% that of controls. In the control group, oocytes appeared to reach a certain critical size before they were ovulated, and fish with higher fecundity ovulated later than their less fecund counterparts. ULO did not affect the timing of ovulation, and ULO fish ovulated eggs with a considerably greater size-range than did controls.