A survey of GP views in intra-uterine contraception

AIMS

To investigate knowledge and attitudes towards intra-uterine contraception.

DESIGN

Anonymous postal survey of 441 GPs (153 female and 288 male GPs) from the FHSA register in Stockport and Manchester.

SETTING

General practices in Stockport and Manchester. Main outcome measure. Response to a series of questions concerning attitudes and knowledge of intra-uterine contraception.

RESULTS

One hundred and forty-two responses were received, giving a 35% response rate. Thirty-four percent of responding GPs did not fit intra-uterine devices (IUDs), with only 10% fitting more than 30 a year. There was a significant trend against IUD fitting by male GPs and GPs aged <40 years. Younger GPs with <10 years experience were significantly more aware of the reliability of intra-uterine contraception, but perceived IUD fitting as inconvenient for both the patient and the doctor. Female GPs had better knowledge and more positive attitudes to IUDs than male GPs.

CONCLUSION

GPs may have difficulties in maintaining expertise. Primary care groups may opt to concentrate fittings in a few expert practices, or refer women to centrally based family planning clinics for IUD fitting.

Differences in susceptibility to gastrointestinal nematode infection between Angus and Brangus cattle in south Louisiana

Breed susceptibility to nematode infection was evaluated in Angus (Bos taurus) and Brangus (B. indicus crossbreed) cattle. A cow-calf herd and a yearling replacement heifer herd were monitored during one grazing season. Calves were born in March and were weaned in October. Individual rectal fecal samples were collected monthly from the two herds and processed for fecal egg counts (FEC) and coprocultures. Cow and calf FEC increased from April, reaching maximum values during the summer. Angus cows and calves had significantly (p<0.05) greater FEC than Brangus cows and calves, and Haemonchus and Cooperia were the predominant genera. Replacement heifer FEC showed a similar pattern with maximum levels during late summer/fall, and Haemonchus was the predominant genus. No significant differences were seen between breeds, however, infection levels were consistently lower in Brangus heifers. Ostertagia was present in cows and heifers only in fall/winter, which is consistent with summer inhibition. The data suggested that cows were an important source of pasture contamination for their susceptible calves and that the Brangus breed was relatively more resistant to infection. The use of B. indicus crossbreeds may help in alleviating reliance on chemical control by reducing the rate of pasture contamination and subsequent infection losses.

The effects of race/ethnicity and income on early childhood asthma prevalence and health care use

OBJECTIVES

Asthma is the most common chronic illness among US children and is most prevalent in low-income and minority groups. We used multivariate models to disentangle the effects of race/ethnicity, income, and other individual-level risk factors on asthma in a population-based sample of children aged 3 years.

METHODS

Data are from the 1988 National Maternal and Infant Health Survey and 1991 Longitudinal Follow-Up. Odds ratios of asthma prevalence, hospitalization, and emergency room use were estimated, with control for socioeconomic characteristics, health behaviors, and insurance.

RESULTS

Asthma prevalence, hospitalization, and emergency room use declined with increasing income for non-Black but not Black children.

CONCLUSIONS

Lifetime income and sociodemographic characteristics do not explain the excess risks of asthma and emergency health care use for asthma among young Black children.

Efficacy of moxidectin 0.5% pour-on against swine nematodes

Forty pigs with induced infections of Ascaris suum, Trichuris suis, Metastrongylus spp., Oesophagostomum dentatum and O. quadrispinulatum were assigned to five-dose groups of moxidectin 0.5% pour-on with eight pigs per dose group. The doses were: moxidectin, 0 (vehicle control), 0.75, 1.00, 1.25, and 1.50 mg/kg(-1) body weight. Worm egg counts (EPG) were made from fecal samples collected on Day 2 pretreatment and on Day 14 or 15 post-treatment. Animals were ranked according to the descending order of A. suum egg counts made on Day 2 and blocked in groups of five. Pigs in blocked groups were assigned randomly to each of the five dose groups. Treatment doses were calculated on the basis of weights taken on Day 1 and were administered topically from the neck to the base of the tail. Pigs were housed by pairs in individual pens provided with self-feeders and automatic waterers. Necropsies were performed on equal numbers of pigs from each treatment group on days 14 and 15 post-treatment. Adult and larval worms were collected, identified and counted by standard parasitological techniques. All counts were transformed by Y=log10 (count+1) transformation prior to analysis. A two-way analysis of variance was conducted and treatment effect was tested for significance at the 5% level. Efficacies based on geometric means and optimal doses were as follows: Ascaris suum, 98.3% at 1.25; Metastrongylus spp., 100% at 0.75; Oesophagostomum quadrispinulatum, 100% at 1.50; and Trichuris suis, 93.5% at 0.75. Efficacy for O. dentatum was from 81.3% to 100%; however, the average number of O. dentatum (30) was too small for significance. Two species of lungworms were present, Metastrongylus apri and M. pudendotectus but they were not speciated at necropsy. As reported for several anthelmintics, the efficacy of moxidectin was variable for Trichuris. The highest efficacy was in the 0.75 dose group with six pigs harboring a few or no worms. The lowest efficacy was in the 1.25 group with only two pigs harboring a few or no worms.

An automated semiquantitative B and T cell clonality assay

BACKGROUND

Rearrangements of the antigen receptor genes in B and T cells generate products of unique length and sequence. Polymerase chain reaction (PCR) assays are routinely used to identify clonal lymphocyte populations by detecting clonal V-J rearrangements or chromosomal translocations within these antigen receptor loci. Multiple primer sets are, however, required to detect the majority of clonal B- and T-cell malignancies. Products from the individual reactions must be analyzed separately to avoid misinterpretation. Moreover, small clonal populations remain difficult to identify. To address these difficulties, we propose that an integrated fluorescence-based approach to clonal B- and T-cell detection would simultaneously identify both B- and T-cell neoplasia; increase amplicon resolution, analytic sensitivity, and assay throughput; produce more comprehensive and semiquantitative data useful for evaluation of hematologic malignancies; and eliminate labor intensive agarose and polyacrylamide gel electrophoresis.

METHODS AND RESULTS

Samples were genomic DNA and cDNA. Differentially labeled primers were used to amplify regions diagnostic for B- and T-cell clonality in a single plate with a single thermocycler program. Combined amplicon products underwent capillary electrophoresis for high resolution fractionation and differential fluorescence detection and quantification. Data were automatically analyzed and archived. In a comparative analysis of a variety of clinical samples, this automated and integrated B- and T-cell assay showed >94% agreement (33 of 35 results) with individual B- and T-cell PCR assays. Furthermore, this assay had an overall monoclonality detection rate of 100%, and as little as 100 ng of sample DNA yielded complete B- and T-cell clonality test results. The limit of detection was approximately 10-2 cells, and amplicons were sized to within 0.1 basepair. Serial dilutions of clonal B- and T-cell lines comprising a coded proficiency panel were identified and correctly ranked. Specificity was 100% as determined by analysis of 18 control samples that were all negative for B- and T-cell clonality.

CONCLUSIONS

Our data show that this automated and integrated B- and T-cell clonality assay system is a sensitive and specific tool useful for rapid identification of clonal lymphocyte populations and will likely have broad clinical applications.

A new strategy for treating nets. Part 2: users' perceptions of efficacy and washing practices and their implications for insecticide dosage

The conventional way to treat a mosquito net with pyrethroid insecticide is to apply a standard dosage every 6-12 months, and to avoid washing the net until just before retreatment. In some places, nets are normally washed much more often than this, and it may then be more appropriate to apply smaller amounts of insecticide after each wash. The choice of strategy must take into account not only biological effectiveness, but also users' perceptions of this effectiveness and their net-washing habits. We used focus groups to compare users' responses to nets treated with different dosages and chemicals. One hundred current net users in urban Dares-Salaam were each given a net that had been pretreated either with permethrin (200 or 500 mg/m2), or with lambdacyhalothrin (3 or 15 mg/m2), or with water. Neither participants nor investigators knew which group had received which treatment. Focus group discussions were held after 2, 8 and 12 weeks. Participants greatly preferred treated nets. Low doses were perceived to be less effective, especially after 8 and 12 weeks. After 12 weeks most participants had washed their nets, despite requests to the contrary Dirty nets were regarded as unhealthy and socially unacceptable. Few participants experienced side-effects or expressed fears about the safety of treatment. We conclude that asking people to refrain from washing their nets is unrealistic. A 'low-dose frequent-treatment' strategy of insecticide application may be more appropriate in the long run. At first, however, low doses give perceptibly inferior protection. An initial high (loading) dose, followed by frequent lower (maintenance) dosages, might solve this problem.

A new strategy for treating nets. Part 1: formulation and dosage

The conventional dosages of pyrethroid insecticides on mosquito nets assume that nets will be retreated at 6-12 month intervals. However, dosage should be related to washing of nets; if nets are only washed once or twice a year, their dosage requirements will be different to those which are washed fortnightly. A 'low-dose, frequent-wash' retreatment system might be technically more appropriate and more affordable where nets are washed frequently, as they are in Dar es Salaam. Moreover, for use as a domestic insecticide, water-based formulations of pyrethroid are preferable to the more commonly used emulsifiable concentrates (ECs). This paper reports laboratory evaluations of three formulations (ECs, Flowable, CS) of three pyrethroids (deltamethrin, lambdacyhalothrin, permethrin). Insecticidal activity was tested using serial bioassays at a range of dosages using Anopheles gambiae. The water-based formulations were no less effective than the ECs, even at the lowest dosages. Nets treated with 3 mg/m2 and then repeatedly washed and retreated after each wash with either 3 mg/m2 or 1 mg/m2 were subjected to gas chromatography analysis. This showed that the amounts of pyrethroid in the nets accumulated rapidly over the first few wash-retreatment cycles and then remained fairly stable over subsequent cycles. These nets gave consistently high bioassay mortalities throughout the experiment, while the mortality declined rapidly after several washes with the nets that were treated at 3 mg/m2 but not retreated. Experimental huts were used to compare the effectiveness of these 2 net retreatment regimes and nets which were not retreated. All nets caused high mortality rates amongst Anopheles females, but had negligible effects on culicines; either in killing them or in preventing feeding. Therefore use of a high 'loading' dose for initial treatment with lower 'maintenance' doses for retreatment may be preferable to ensure that net users promptly perceive the benefits of the insecticide against culicines.

Notification of real-time clinical alerts generated by pharmacy expert systems

We developed and implemented a strategy for notifying clinical pharmacists of alerts generated in real-time by two pharmacy expert systems: one for drug dosing and the other for adverse drug event prevention. Display pagers were selected as the preferred notification method and a concise, yet readable, format for displaying alert data was developed. This combination of real-time alert generation and notification via display pagers was shown to be efficient and effective in a 30-day trial.

Urinary bombesin-like peptide levels in infants and children with bronchopulmonary dysplasia and cystic fibrosis

Compared to normal infants and children, there are increased numbers of neuroendocrine cells with bombesin-like peptide (BLP) immunostaining in the lungs of infants and children with bronchopulmonary dysplasia (BPD) and cystic fibrosis (CF). However, there are no data documenting levels of urinary BLP in normal infants and children, or in children with lung disease. We therefore determined the normal developmental pattern for urinary BLP excretion in healthy infants and children, and in infants and children with BPD and CF, and correlated these findings with the subjects' clinical course. We measured urinary BLP levels in 110 subjects: 54 controls, 33 with BPD, and 23 with CF. An age-dependent decline in urinary bombesin levels was evident in the control and BPD subjects, but not in those with CF. There were no statistically significant differences in BLP levels between normal infants and those with BPD. Mean BLP levels were higher in the more immature preterm infants with BPD who required increased ventilatory support. The highest mean BLP levels were documented in BPD infants under age 3 months (882 fmol/mg creatinine), in controls between 3 and 12 months of age (625 fmol/mg creatinine), and in 12-60-month-old CF subjects (486 fmol/mg creatinine). Thus there is an age-dependent decline in BLP levels in controls and BPD, but not in CF. We speculate that the elevated urinary BLP levels in infants and children with BPD and CF may reflect increased pulmonary neuroendocrine cell activity in these conditions, due to the epithelial regenerative response to airway damage and repair.

Can anything be done to maintain the effectiveness of pyrethroid-impregnated bednets against malaria vectors?

Pyrethroid-treated bednets are the most promising available method of controlling malaria in the tropical world. Every effort should be made to find methods of responding to, or preventing, the emergence of pyrethroid resistance in the Anopheles vectors. Some cases of such resistance are known, notably in An. gambiae in West Africa where the kdr type of resistance has been selected, probably because of the use of pyrethroids on cotton. Because pyrethroids are irritant to mosquitoes, laboratory studies on the impact of, and selection for, resistance need to be conducted with free-flying mosquitoes in conditions that are as realistic as possible. Such studies are beginning to suggest that, although there is cross-resistance to all pyrethroids, some treatments are less likely to select for resistance than others are. Organophosphate, carbamate and phenyl pyrazole insecticides have been tested as alternative treatments for nets or curtains. Attempts have been made to mix an insect growth regulator and a pyrethroid on netting to sterilize pyrethroid-resistant mosquitoes that are not killed after contact with the netting. There seems to be no easy solution to the problem of pyrethroid resistance management, but further research is urgently needed.

A comparative study of in vivo mutation assays: analysis of hprt, lacI, cII/cI and as mutational targets for N-nitroso-N-methylurea and benzo[a]pyrene in Big Blue mice

We have compared the response of the native hprt gene and the lacI, cII, and cI transgenes in Big Blue B6C3F1 mice following treatment with either N-nitroso-N-methylurea (MNU) or benzo[a]pyrene (BaP). Three weeks after mutagen treatment splenic T cells were isolated from the animals, and samples were either cultured to measure mutation at the native hprt locus or used to extract genomic DNA for transgene mutation analysis. Phage rescued from extracted DNA were plated in the presence of 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside (X-gal) to score lacI mutations, or plated on a hflAB lawn to score cII and cI mutants. With MNU hprt mutant frequency increased in a dose-related, sublinear manner up to 78-fold above background at the highest dose tested (20 mg/kg). In comparison, the lacI transgene yielded only a 3.1-fold increase at this dose, and the cII and cI transgenes did not show any increase. With 150 mg/kg BaP a 5.8- and 8.7-fold increase in mutant frequency was observed at hprt and lacI, respectively, while only a 1.3-fold increase was observed at cII. DNA sequencing revealed an increase in GC-->TA transversions among the cII mutants, suggesting that the increase was related to BaP exposure. No significant increase in cI mutant frequency was observed. Therefore, the order of mutation assay sensitivity was hprt>lacI>cII/cI with MNU, and hprt approximately lacI> cII/cI with BaP. While the hflAB selection system offers significant advantages with respect to cost and effort when compared to the lacI assay, additional evaluation of its sensitivity is warranted.

Biliary pancreatitis: the era of laparoscopic cholecystectomy

OBJECTIVE

To evaluate the efficacy and safety of a combined approach to the treatment of biliary pancreatitis using laparoscopic cholecystectomy and selective endoscopic retrograde cholangiopancreatography (ERCP).

DESIGN

Consecutive case series.

SETTING

Tertiary care center.

PATIENTS

All patients undergoing primary operations for biliary pancreatitis during 2 time periods were included. In the open era (June 1982 through May 1988), there were 276 patients; in the laparoscopic era (January 1996 through June 1997), there were 114 patients.

INTERVENTIONS

Open cholecystectomy with or without common bile duct exploration (CBDE); laparoscopic cholecystectomy with selective ERCP and/or laparoscopic CBDE.

MAIN OUTCOME MEASURES

Two periods were compared for morbidity, mortality, the duration of preoperative and postoperative stays, and the total length of hospitalization.

RESULTS

Both groups were demographically similar and had the same mortality (1.9%). Laparoscopic cholecystectomies provided a preoperative stay comparable to open cholecystectomy (6.4 vs 5.8 days), a shorter postoperative stay (1.5 vs 8.5 days), a lower incidence of CBDE (6.6% vs 26%), and a lower morbidity (8% vs 13.7%). The addition of an ERCP to laparoscopic cholecystectomy was associated with prolongation of the preoperative stay (7.4 vs 5.0 days), a comparable postoperative stay, a lower conversion rate (7.5% vs 13%), and fewer CBDEs (3% vs 13%). In 27 (42%) of the 64 ERCP cases, no stones were found.

CONCLUSIONS

Treatment of biliary pancreatitis with combined laparoscopic cholecystectomy and selective ERCP is safe and effective and is associated with a shorter hospitalization and fewer CBDEs than open cholecystectomy. Unnecessary ERCPs can be reduced by improved selection criteria or greater dependence on operative CBDE.

Serum paraoxonase (PON1) 55 and 192 polymorphism and paraoxonase activity and concentration in non-insulin dependent diabetes mellitus

Human serum paraoxonase (PON1) is located on high density lipoprotein and has been implicated in the detoxification of organophosphates and possibly in the prevention of low density lipoprotein lipid peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine (A genotype) and arginine (B genotype) at position 192 and the other leucine (L genotype) and methionine (M genotype) at position 55. We investigated the effect of these polymorphisms on serum PON1 activity and concentration in 252 non-insulin dependent diabetes mellitus (NIDDM) individuals and 282 non-diabetic controls. Serum PON1 activity in the controls (214.6 nmol/min per ml (26.3-620.8)) was significantly higher than in NIDDM (158.7 nmol/min per ml (3.6-550.5) (P < 0.001) as was serum PON1 concentration (89.1 microg/ml (16.8-527.4)) compared to 76.7 microg/ml (3.6-443.8) (P < 0.01). In the control population MM homozygotes had significantly lower serum PON1 activity regardless of the 192 polymorphism whereas in NIDDM both LM and MM genotypes had lower serum PON1 activity than LL homozygotes only when the 192 AA genotype was present. Serum PON1 concentration was lower in NIDDM with AA/LM, AA/LL, AB/LL and AB/MM genotypes than in controls. Differences in PON1 activity were the major cause of differences in specific activity between genotypes. Neither the PON1 55 or 192 polymorphisms consistently influenced the serum lipid or lipoprotein concentrations in either population. Low serum PON1 activity in NIDDM may be related to an increased tendency to lipid peroxidation and may also increase susceptibility to toxicity from organophosphate exposure. Our findings thus raise the possibility that PON1 may be of importance in both the genetic and acquired predisposition to premature atherosclerosis and neuropathy in diabetes.

DNA synthesis inhibition as an indirect mechanism of chromosome aberrations: comparison of DNA-reactive and non-DNA-reactive clastogens

Positive results in the in vitro assay for chromosome aberrations sometimes occur with test chemicals that apparently do not react with DNA, being negative in tests for mutation in bacteria, for DNA strand breaks, and for covalent binding to DNA. These chromosome aberrations typically occur over a narrow concentration range at toxic doses, and with mitotic inhibition. Indirect mechanisms, including oxidative damage, cytotoxicity and inhibition of DNA synthesis induced by chemical exposure, may be involved. Understanding when such mechanisms are operating is important in evaluating potential mutagenic hazards, since the effects may occur only above a certain threshold dose. Here, we used two-parameter flow cytometry to assess DNA synthesis inhibition (uptake of bromodeoxyuridine [BrdUrd]) associated with the induction of aberrations in CHO cells by DNA-reactive and non-reactive chemicals, and to follow cell cycle progression. Aphidicolin (APC), a DNA polymerase inhibitor, induces aberrations without reacting with DNA; 50 microM APC suppressed BrdUrd uptake during a 3-h treatment to <10% of control levels. Several new drug candidates induced aberrations concomitant with marked reductions in cell counts at 20 h (to 50-60% of controls) and suppression of BrdUrd uptake (<15% of control). Several non-mutagenic chemicals and a metabolic poison, which induce DNA double strand breaks and chromosome aberrations at toxic dose levels, also suppressed DNA synthesis. In contrast, the alkylating agents 4-nitroquinoline-1-oxide, mitomycin C, methylnitrosourea, ethylnitrosourea, methylmethane sulfonate and ethylmethane sulfonate, and a topoisomerase II inhibitor, etoposide, produced many aberrations at concentrations that were less toxic (cell counts >/=73% of controls) and gave little inhibition of DNA synthesis during treatment (BrdUrd uptake >/=85% of controls), although cell cycle delay was seen following the 3-h treatment. Thus, inhibition of DNA synthesis at the time of treatment is supporting evidence for an indirect mechanism of aberrations, when there is no direct DNA reactivity.

Developmental screening scores among preschool-aged children: the roles of poverty and child health

OBJECTIVES

To investigate, using a nationally representative sample of preschool-aged children, the relationship among poverty history, child health, and risk of an abnormal developmental screening score.

METHODS

Data were derived from the 1988 National Maternal and Infant Health Survey and 1991 Longitudinal Follow-up. Family income in the child's prenatal year and at 2 years old defined a poverty history for each child. Multivariate logistic regression was used to estimate the effects of poverty history on risk of an abnormal screening score or delays in large-motor, personal-social, or language subscales.

RESULTS

Poor and near-poor children were 1.6 to 2.0 times as likely as nonpoor children to be classified as abnormal, even when maternal and household characteristics and the child's health history were taken into account. Preterm birth, chronic illness, dearth of reading materials in the home, and maternal depression were also associated with elevated risks of abnormal scores.

CONCLUSIONS

Poverty is the largest single predictor of an abnormal developmental screening score. The implications of inadequate medical care among poor children for the interpretation of individual screening scores and for amelioration of problems are also discussed.

Biomedical risk factors for hospital admission in older adults

OBJECTIVES

This study examines the influence of risk factors such as cigarette smoking, blood pressure, serum cholesterol, or chronic illness on frequency of hospital admission in a population-based sample.

METHODS

Data from the National Health and Nutrition Examination Survey I Epidemiologic Followup Study for 6,461 adults aged 45 years and older were used to assess the influence of risk factors measured by interview, physical examination, and laboratory tests on frequency of hospital admission over a 12- to 16-year follow-up period. Cox proportional hazard regressions were estimated separately for men and women and for ages 45 to 64 years and 65 years and older. SUDAAN software was used to correct for clustering, stratification, unequal weighting, and multiple observations per respondent.

RESULTS

Risk of hospitalization was higher for current but not former smokers (relative risk [RR] = 1.17-1.34 for different age-sex groups; P < 0.01), higher blood pressure (RR = 1.25-1.28 for ages 45-64; RR = 1.07-1.15 for ages 65 and older; P < 0.01), and lower serum albumin (RR = 1.08-1.14; P < 0.01). Diabetes, lung conditions, heart attack, and ulcer each were associated with higher risk in at least three of the four age-sex groups, as was arthritis among the middle-aged (45-64 years). Serum cholesterol was not associated with hospitalization.

CONCLUSIONS

Chronic conditions with high morbidity as well as many factors associated with mortality are associated with a higher frequency of hospitalization.

Comparison of motility and membrane integrity to assess rat sperm viability

Rat sperm motility and membrane integrity were compared as endpoints for viability. Sperm motility was measured by computer-assisted semen analysis (CASA), whereas membrane integrity was assessed by flow cytometric analysis of sperm stained with two nucleic acid stains, SYBR-14 and propidium iodide. The two techniques were compared in experiments that examined sperm viability over time and by analysis of known mixtures of control and freeze/thaw-killed sperm. Results from the two approaches were quantitatively very similar. Sperm from rats treated with dibromoacetic acid (600 or 1200 mg/kg) or alpha-chlorhyrin (100 mg/kg) were also analyzed. Neither technique detected a treatment-related effect with dibromoacetic acid. CASA identified a significant decrease in sperm motility in alpha-chlorhyrin-treated rats, whereas flow cytometric analysis did not find a measureable change in sperm membrane integrity. Because decreases in sperm motility would be expected to directly affect fertility, CASA may be a more robust endpoint for risk assessment in reproductive toxicology studies than flow cytometric analysis of membrane integrity.

Epidemiology of gastrointestinal nematode parasitism in Suffolk and Gulf Coast Native sheep with special emphasis on relative susceptibility to Haemonchus contortus infection

An eight-year study was conducted to define the epidemiology of gastrointestinal nematode infection in Suffolk and Gulf Coast Native (Native) breeds of sheep, and to determine if the Native sheep is more resistant to infection. For the initial three years, each breed grazed separate pastures where anthelmintic treatments were administered to individual animals on a salvage basis. For the last five years, both breeds grazed concurrently; anthelmintic treatments were administered to individual animals on a salvage basis for the first three years, and to all animals, when treatment criteria were met, for the last two years. The fecal egg count (FEC) and blood packed cell volume (PCV) were monitored, and tracer lamb nematode burdens were determined. Overall, FEC for both breeds increased in the spring (periparturient rise) for most years and in the summer for all years. Under separate grazing conditions, Native ewes and lambs had consistently lower infection levels than Suffolk ewes and lambs. During the haemonchosis season (June-September) each year, Suffolk ewe and lamb PCV decreased, and Native ewe and lamb PCV remained relatively stable. The salvage treatment protocol resulted in 27 treatments for Suffolk and one for Native ewes; similarly for lambs, 13 for Suffolk and zero for Native. Tracer lambs grazed with their respective breed, and the FEC and mean total nematode burden corresponded with the pattern of infection for their respective breed. The predominant nematodes found in Suffolk and Native tracer lambs were Haemonchus contortus and Trichostrongylus spp., respectively. Under concurrent grazing conditions, the same seasonal repeatable pattern of infection was present and was exhibited by both breeds, with the Native ewes and lambs being consistently and significantly (p < or = 0.05) lower for FEC and higher for PCV. The salvage treatment protocol resulted in 57 and zero treatments for Suffolk and Native ewes, respectively; for lambs, 46 and 11. Tracer lamb nematode burdens again corresponded to their respective breed pattern of infection, with H. contortus and Trichostrongylus spp. being predominant in Suffolk and Native lambs, respectively. Data from all tracer lambs showed a relatively low level of hypobiosis (H. contortus only), and, although there was no consistent hypobiosis season, the tendency was for a higher level to occur in the fall. These results showed that the classic repeatable seasonal pattern of gastrointestinal nematode infection occurred in both breeds of sheep, and that Native sheep were more resistant to infection (specifically H. contortus) than Suffolk sheep.

Bladder petechiae after cystoscopy and hydrodistension in men diagnosed with prostate pain

PURPOSE

We determined if men with prostate pain syndromes have petechiae in the bladder after hydrodistension.

MATERIALS AND METHODS

A total of 60 men with the diagnosis of prostate pain and without bacteriuria underwent cystoscopy and hydrodistension under a general or regional anesthetic.

RESULTS

Of the 60 men 35 (58%) had moderate to severe petechiae similar in appearance to women with interstitial cystitis after hydrodistension. Men with moderate to severe bladder petechiae had fewer leukocytes in expressed prostatic secretions, smaller bladder capacities and less often testicular pain than men with more normal appearing bladders after hydrodistension. Symptomatic improvement 2 to 6 weeks after hydrodistension was more common in men with moderate to severe petechiae than in those with fewer petechiae. Absence of rectal pain predicted symptomatic improvement after hydrodistension.

CONCLUSIONS

We suggest that bladder petechiae, and possibly interstitial cystitis or a related condition, may be more frequently associated with prostate pain syndromes in men than previously appreciated.

Cell-specific regulation of expression of plasma-type platelet-activating factor acetylhydrolase in the liver

Platelet-activating factor (PAF) is a potent proinflammatory phospholipid mediator that causes hypotension, increases vascular permeability, and has been implicated in anaphylaxis, septic shock and several other inflammatory responses. PAF is hydrolyzed and inactivated by the enzyme PAF-acetylhydrolase. In the intact rat, a mesenteric vein infusion of lipopolysaccharide (LPS) served as an acute, liver-focused model of endotoxemia. Plasma PAF-acetylhydrolase activity increased 2-fold by 24 h following LPS administration. Ribonuclease protection experiments demonstrated very low levels of plasma-type PAF-acetylhydrolase mRNA transcripts in the livers of saline-infused rats; however, 24 h following LPS exposure, a 20-fold induction of PAF-acetylhydrolase mRNA was detected. In cells isolated from endotoxin-exposed rat livers, Northern blot analyses demonstrated that Kupffer cells but not hepatocytes or endothelial cells were responsible for the increased PAF-acetylhydrolase mRNA levels. In Kupffer cells, plasma-type PAF-acetylhydrolase mRNA was induced by 12 h, peaked at 24 h, and remained substantially elevated at 48 h. Induction of neutropenia prior to LPS administration had no effect on the increase in PAF-acetylhydrolase mRNA seen at 24 h. Although freshly isolated Kupffer cells contain barely detectable levels of plasma-type PAF-acetylhydrolase mRNA, when Kupffer cells were established in culture, PAF-acetylhydrolase expression became constitutively activated concomitant with cell adherence to the culture plates. Alterations in plasma-type PAF-acetylhydrolase expression may constitute an important mechanism for elevating plasma PAF-acetylhydrolase levels and an important component in minimizing PAF-mediated pathophysiology in livers exposed to endotoxemia.

Endothelin-1 production by hepatic endothelial cells: characterization and augmentation by endotoxin exposure

Activation of endothelin (ET) receptors in the liver causes vasoconstriction, glucose production, and lipid and peptide mediator synthesis. In the intact rat, a bolus infusion of endotoxin into a mesenteric vein served as an acute exposure model of endotoxemia. In response to this challenge, a ninefold increase in hepatic ET-1 mRNA occurred within 3 h. The plasma level of immunoreactive ET-1 (irET-1) increased correspondingly by 8.5-fold within 6 h. ET-1 mRNA levels in liver endothelial cells (EC) isolated from livers of endotoxin-treated rats at various times after endotoxin challenge showed a more gradual increase. Northern blot analyses of the major liver cell types demonstrated that ET-1 mRNA was most abundant in the EC. The present results document a significant increase in the circulating level of irET-1 during episodes of endotoxemia. The increased hepatic ET-1 production in response to endotoxin infusion suggests that ET-1 produced in the liver could make a significant contribution to the plasma irET-1 and may be an important component in the hepatic responses to systemic trauma.

Erythrocyte incorporation and absorption of 58Fe in premature infants treated with erythropoietin

We hypothesized that treatment of very low birth weight premature infants with r-HuEPO would increase erythrocyte incorporation and gastrointestinal absorption of iron. Infants with birth weights < or = 1.25 kg and gestational ages < 31 wk were randomized to receive 6 wk of 500 U of r-HuEPO/kg/wk (epo group, n = 7) or placebo (placebo group, n = 7). All infants received daily enteral supplementation with 6 mg of elemental iron per kg. An enteral test dose of a stable iron isotope, 58Fe, was administered after the 1st ("early dosing") and 4th ("late dosing") wk of treatment. Mean (+/-SD) erythrocyte incorporation of the dose of 58Fe administered determined 2 wk after early dosing was significantly greater in the epo group compared with the placebo group (4.4% +/- 1.6 versus 2.0 +/- 1.4%, p = 0.013). In contrast, after late 58Fe dosing, there was no difference between groups in incorporation (3.8 +/- 1.6% versus 5.5 +/- 2.7%). Within the epo group, percentage erythrocyte incorporation of 58Fe did not differ between early and late dosing, whereas in the placebo group it increased 3-fold (p < 0.01). Percentage absorption of 58Fe was not different between the epo and placebo groups after both early dosing (30 +/- 22% versus 34 +/- 8%) and late dosing (32 +/- 9% versus 31 +/- 6%). Absorption of nonlabeled elemental iron and 58Fe were significantly correlated with one another. The percentage of the absorbed 58Fe dose incorporated into Hb was not different between groups. We conclude that, although erythropoietin treatment stimulates erythrocyte iron incorporation in premature infants, it has no effect on iron absorption at the r-HuEPO dose studied.

Adequacy of hormone replacement therapy for osteoporosis prevention assessed by serum oestradiol measurement, and the degree of association with menopausal symptoms

BACKGROUND

Patients on hormone replacement therapy (HRT) for osteoporosis prevention rather than menopausal symptom control may be asymptomatic, despite inadequate replacement and low serum oestradiol (E2) levels. In the primary health care setting, therapeutic monitoring of HRT is not carried out routinely so that patients with serum E2 levels inadequate to protect bone may be missed.

AIM

To determine the proportion of women on transdermal E2 preparations with serum E2 levels insufficient to protect bone and to assess the value of a questionnaire-derived menopausal symptom score (MSS) for detecting these patients.

METHOD

A cross-sectional analysis of 45 patients aged 35-70 years using transdermal E2 preparations obtained from a computer register of 14500 patients in a suburban practice. One blood sample was obtained from each patient at the time the MSS questionnaire was completed. Serum E2 concentration was measured using a fluoroimmunoassay and compared with the MSS. Levels below 150 pmol/l were considered to be insufficient to protect bone. The diagnostic accuracy of the MSS in screening for levels below 150 pmol/l was determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

The median (95% CI) serum E2 was 147 pmol/l (126-198 pmol/l) and levels were below 150 pmol/l in 24 out of 45 patients. There was no difference in the MSS (median, 95% CI) between those with serum E2 < 150 pmol/l (8.5, 5.0-17) and > or = 150 pmol/l (9.0, 5.0-14; P = 0.477). The degree of association between the serum E2 and the MSS, using the Spearman rank correlation coefficient, rs (95% CI) was small and not significant (-0.04, -0.34 to 0.26; P = 0.398). ROC curve analysis revealed an area under the curve (95% CI) of 0.51 (0.33-0.68).

CONCLUSIONS

More than half the women were inadequately replaced to protect against osteoporosis. Furthermore, the MSS was of no value in screening for those with low serum E2 levels. Serum E2 levels should be monitored in women on HRT for osteoporosis prevention and the E2 dosage adjusted accordingly.

Incidence and significance of subdiaphragmatic air following laparoscopic cholecystectomy

Subdiaphragmatic free-air may be indicative of a perforated viscus; however, it is normally present after open abdominal surgery. The objective of this study was to determine the significance and incidence of subdiaphragmatic free air following laparoscopic cholecystectomy (LC). Cases of intestinal perforation following laparoscopic cholecystectomy from 1991 to 1995 at The University of Texas Health Science Center at San Antonio were reviewed and their association with subdiaphragmatic free air was determined. Twenty-five patients undergoing LC and 20 patients undergoing open cholecystectomy (OC) were prospectively evaluated with chest radiographs to determine the incidence and quantity of nonpathologic postoperative free air. Four cases of intestinal perforation resulting from trocar injuries or electrocautery burns occurred among 1603 LCs during this study period, for an incidence of 0.2 per cent. Three of the four patients with perforations were diagnosed postoperatively (2-5 days), and two patients had a moderate volume of subdiaphragmatic free air that aided the diagnosis. The incidence of subdiaphragmatic air following LC was 24 per cent, compared to 60 per cent for OC (P < 0.05). Eighty-three per cent of patients with retained air after LC had a minimal volume, compared to 67 per cent of patients after OC (P < 0.05). Nonpathologic subdiaphragmatic free air may normally be present following laparoscopic cholecystectomy but is uncommon 24 hours after the operation. When present, only a small volume is usually detectable. In the rare situation of intestinal perforation resulting from LC, subdiaphragmatic free air may be an important diagnostic finding.

Susceptibility of Suffolk and Gulf Coast Native suckling lambs to naturally acquired strongylate nematode infection

Three trials compared responses to naturally-acquired strongylate nematode infection between suckling Suffolk and Gulf Coast Native (Native) lambs which grazed together. In Trial 1 (1992), infection in 14 lambs of each breed was monitored from birth to 12 weeks of age using fecal egg count (FEC) and blood packed cell volume (PCV). In Trial 2 (1993), two age-matched lambs of each breed were sacrificed at seven and ten weeks of age to estimate nematode burdens. In Trial 3 (1994), infection in 18 lambs of each breed was monitored (FEC, PCV, white blood cell count, differential leukocyte count, and anti-Haemonchus contortus immunoglobulin level) from birth to 8 weeks of age, at which time six age-matched lambs of each breed were sacrificed to estimate nematode burdens. The remaining 24 lambs were monitored until 12 weeks of age. In both Trials 1 and 3, infection in Native lambs peaked and then declined between 6-10 weeks of age. Infection in Suffolk lambs continued to increase as evidenced by increasing FEC with concomitant reduction in PCV, higher morbidity and mortality (Trial 1), and number of anthelmintic treatments required (Trial 3). In Trials 2 and 3, the principal nematode found at necropsy was H. contortus, and infection level was consistently lower (> 64%) in Native compared with Suffolk lambs. In Trial 3, there was no difference between breeds for WBC, any leukocyte type, or anti-H. contortus immunoglobulin level. These results demonstrated that suckling Native lambs developed resistance to H. contortus infection during their first exposure to infection at an age when they are considered immune incompetent and colostrally transferred anti-H. contortus immunoglobulin did not appear to be involved in the resistance.

Effect of oxygen supply on metabolism of immobilized and suspended Escherichia coli

The effect of reduced oxygen supply on the production of a recombinant protein (plasmid-encoded beta-galactosidase) was investigated in Escherichia coli. A novel modified bubble tank reactor was used to provide a direct comparison between immobilized and suspended cells in identical environments except for the immobilization matrix. Decreased oxygen supply led to increased beta-galactosidase synthesis by both immobilized and suspended cells. Immobilized cells produced similar amounts of beta-galactosidase as the suspended cells. Lactose consumption and acetate production, on a per cell basis, were significantly higher in immobilized cells, suggesting that immobilized cells utilized fermentative metabolism. However, a transport analysis of the immobilized cell system showed that immobilized cells were not subject to either external or internal mass transfer gradients.

AIDS knowledge among New Jersey adults

Data were collected from New Jersey adults. Most respondents know the major means by which the disease is transmitted and that a cure and vaccine are not available.

Serum IgE levels in dairy calves: evaluation of parasite and pasture exposure as possible determinants of IgE response

Immunoglobulin E (IgE) has been regarded as an antibody isotype important in the host response to helminth infection and allergic conditions. Level of parasitic infection has been associated with serum total IgE level and the highest levels have been observed during the spring when environmental allergen levels are also high. Two groups of five parasite-native calves were maintained in a barn and one of the groups received an experimental gastrointestinal nematode infection. One group of five parasite-native calves was placed on clean pasture and another group of five was placed on a nematode-contaminated pasture. The contaminated pasture group acquired an acute gastrointestinal nematode infection, compared with a relatively low infection in the experimentally infected group. The only difference between the groups was a significant change (increase) in IgE level in calves on contaminated pasture, compared with the other three groups. This suggested that the infection acquired on pasture and not the experimental infection or environmental allergens encountered while grazing or in the barn stimulated an IgE response.

Antigen-presenting function of the mouse CD1 molecule

CD1 molecules are distantly related to major histocompatibility complex (MHC)-encoded class I molecules, and they are coexpressed with beta2 microglobulin (beta2m). In the mouse, CD1 is expressed by intestinal epithelial cells and also by some cells in spleen and lymph node. We have shown that surface expression of mouse CD1 (mCD1) is not dependent upon a functional transporter associated with antigen processing (TAP). This, and other data, suggest that mCD1 may acquire peptides in an intracellular compartment other than the endoplasmic reticulum, where classical class I molecules bind peptide. mCD1 molecules also are distinct from classical class I molecules with regard to the types of peptides that they bind. We have demonstrated that mCD1 molecules preferentially bind peptides much longer than the 8-9 amino acids typical of the peptides that bind to classical class I molecules. The sequence motif for mCD1 peptide binding is characterized by the presence of bulky and hydrophobic amino acid side chains. We have generated mCD1-restricted and peptide-specific T-cell lines, thereby demonstrating the immunologic relevance of peptide binding to mCD1. The reactive T cells are TCR alphabeta+ and CD8+, a phenotype typical of many lymphocytes in both lymph node and intestinal mucosae. We speculate that mCD1 molecules may be capable of sampling peptides from the gut lumen and presenting them to mucosal T lymphocytes. In this way, they may function in the maintenance of normal mucosal homeostasis, and perhaps also in the induction of systemic tolerance to antigens delivered by the oral route. In summary, CD1 molecules are a novel category of antigen-presenting molecules that have features in common with class I molecules, features in common with class II, and properties distinct from either subset of antigen-presenting molecules. Further studies of the antigen-presenting function of these molecules are certain to yield new insight into immune regulation and perhaps also into the mechanism of oral tolerance.

Hormonal stimulation of calcium mobilization in the isolated perfused rat pancreas

Hormone-stimulated cellular Ca2+ mobilization in the isolated perfused rat pancreas was investigated by analyzing the efflux profiles of 45Ca2+ from 45Ca(2+)-loaded pancreata following agonist stimulation. The increased 45Ca2+ efflux reflects the enhanced exchange of Ca2+ across the plasma membrane as a result of increased [Ca2+]i. Both high and low concentrations of the cholecystokinin analog, cerulein, applied to the isolated perfused pancreas gave rise to an increased release of 45Ca3+. The patterns of the increase in 45Ca2+ release were consistently different for high and low concentrations of the agonist. Cerulein infused at a concentration of 10(-11) M induced a release of a small but significant amount of 45Ca2+ which could be abolished by 8-(N,N-diethylamine)octyl-3,4,5-trimethoxy-benzoate (TMB-8), but was not affected by ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). Cerulein stimulation at 10(-9) M elicited a marked increase in 45Ca2+ release which was minimized by EGTA, but not by TMB-8. Also, infusion of cerulein stimulated a concentration-dependent amylase secretion response which displayed the same TMB-8- and EGTA-sensitivity pattern as the 45Ca2+ release response. The present study suggests (i) that cellular Ca2+ influx is a prominent feature of the increased 45Ca2+ efflux (i.e., increased [Ca2+]i) induced by pharmacological concentrations of cerulein while physiological concentrations of cerulein cause an increase in [Ca2+]i which is due predominantly to a release of internal Ca2+; and (ii) [Ca2+]i changes are essential for pancreatic enzyme secretion. Although isolated pancreatic acini or cells may lose their sensitivity and physiological responses to various agonists during isolation and preparation, the isolated perfused pancreas is a suitable and very sensitive model in which to study the physiology of Ca2+ mobilization and enzyme secretion.

Effects of rooting medium and fertilizer rate on response of white clover to tropospheric ozone

Two white clover (Trifolium repens L.) clones with varying sensitivity to O(3) are being developed as a system to indicate effects of ambient concentrations of tropospheric O(3) on plants. One clone (NC-S) is highly sensitive to O(3) and the other (NC-R) is highly resistant. The system relies on periodic measurement of foliar injury, foliar chlorophyll, and forage production of NC-S and NC-R grown in 15-liter pots throughout a summer season. Relative amounts of foliar injury and ratios (NC-S/NC-R) for chlorophyll and forage weight can be used to estimate biologically effective ambient O(3) concentrations. The effect of variation in rooting media formulation and fertilizer rate on response of NC-S and NC-R to ambient O(3) was determined in the present study. In the rooting medium experiment, clover was grown in three mixtures of sandy loam topsoil:course washed sand:Metro Mix 220 (ratios (by volume) of 2:1:1, 2:1:5, and 6:1:1). In the fertilizer experiment, clover was grown in the 2:1:1 medium at four fertilizer rates (soluble 5-11-26 (N-P-K) at 0.0, 0.5, 1.0, or 2.0 g per pot). Ozone caused more foliar injury, more chlorosis, and a greater decrease in forage production of NC-S than of NC-R in all studies. Rooting media treatments affected both clones similarly and occasional clone x media interactions were judged to be random. Forage production by NC-S, relative to that of NC-R, was generally greater in the 0.0 fertilizer treatment, but the forage ratios were similar at all other fertilizer treatments. The relative response of NC-S and NC-R to O(3) is fairly stable under cultural conditions that support normal plant growth.

Evidence for altered cellular calcium in the pathogenetic mechanism of acute pancreatitis in rats

Although several pathophysiological sequences, such as protease activation, free radical generation, and inflammatory mediator release, have been described in acute pancreatitis, the precise mechanism by which acute pancreatitis is initiated is unknown. Cellular calcium, a key physiological signaling element in cell function and also a crucial pathological intracellular messenger in cell injury, appears to be involved in the initiation and development of acute pancreatitis. The present study provides several lines of evidence supporting this suggestion. First, verapamil (a calcium channel blocker) administration was associated with a significant protection of rats from acute pancreatitis induced by high doses of cerulein (50 micrograms/kg/hr, subcutaneously), as evidenced both histologically and biochemically. Second, verapamil was found to minimize the increased tissue levels of calcium, platelet-activating factor, and thromboxane B2 detected during acute pancreatitis. Third, acute pancreatitis could be observed in rats with elevated serum calcium levels at low doses of cerulein (5 micrograms/kg/hr, subcutaneously), but could not be observed in rats with normal serum calcium levels treated with low doses of cerulein. It is proposed that cellular calcium, which is a critical signaling component in the synthesis and release of inflammatory mediators and several other events, may be an important factor in the pathogenesis of cerulein-induced acute pancreatitis.

Effects of rhizobium, arbuscular mycorrhizal fungi and anion content of simulated rain on subterranean clover

An experiment was conducted to determine the extent to which rhizobia, mycorrhizal fungi, and anions in simulated rain affect plant growth response to acid deposition. Germinating subterranean clover seeds were planted in steam-pasteurized soil in pots and inoculated with Rhizobium leguminosarum, Glomus intraradices, Glomus etunicatum, R. leguminosarum + G. intraradices, R. leguminosarum + G. etunicatum, or no microbial symbionts. Beginning 3 weeks later, plants and the soil surface were exposed to simulated rain in a greenhouse on 3 days week(-1) for 12 weeks. Rain solutions were deionized water amended with background ions only (pH 5.0) or also adjusted to pH 3.0 with HNO3 only, H2SO4 only, or a 50/50 mixture of the two acids. Glomus intraradices colonized plant roots poorly, and G. intraradices-inoculated plants responded like nonmycorrhizal plants to rhizobia and rain treatments. Variation in plant biomass attributable to different rain formulations was strongest for G. etunicatum-inoculated plants, and the effect of rain formulation differed with respect to nodulation by rhizobia. The smallest plants at the end of the experiment were noninoculated plants exposed to rains (0.38 g mean dry weight total for 3 plants pot(-1)). Among nonnodulated plants infected by G. etunicatum, those exposed to HNO3 rain were largest, followed by plants exposed to HNO3 + H2SO4, pH 5.0, and H2SO4 rain, in that order. Among plants inoculated with both R. leguminosarum + G. etunicatum, however, the greatest biomass occurred with pH 5.0 rains, resulting in the largest plants in the study (1.00 g/3 plants). Treatment-related variation among root and shoot biomass data reflected those for whole-plant biomass. Based on quantification of biomass and N concentrations in shoot and root tissues, total N content of plants inoculated with G. etunicatum alone and exposed to the HNO3 + H2SO4 rains was approximately the same as plants inoculated with R. leguminosarum + G. entunicatum and exposed to pH 5 rains. Thus, the acid-mixture rains and rhizobia under no acid deposition provided approximately equal amounts of N in biomass. The significant interactions among rain formulation and the symbiotic status of the plants suggest that conclusions concerning the impact of acid deposition on plants in the environment cannot be considered reliable because most experiments on which such assessments are based have not tested confounding influences of microorganisms and precipitation characteristics.

Midinfrared modulation through the use of field-induced scattering in ferroelectric liquid crystals

The feasibility of the use of modulation devices based on field-induced transient scattering in ferroelectric liquid crystals (LC) to replace mechanical choppers used in uncooled infrared-imaging systems was investigated. Devices fabricated with ITO-coated ZnSe substrates and a ferroelectric LC path length of 25 µm were able to modulate optical radiation by transient forward scattering at rates approaching 20 kHz. Through the use of a commercial arbitrary waveform generator and associated PC-based software, drive waveforms were developed that produced a variable, square-wave optical-modulation pattern by the extension of the duration of the scattering state to periods ranging from hundreds of microseconds to milliseconds. The ability of these extended-scattering-mode (ESM) devices to modulate radiation in both the visible and midinfrared regions was verified in a simple experiment through the use of a Fourier-transform infrared spectrometer, in which an unoptimized ESM device displayed a 40% modulation dep th for IR radiation in the 8-12-µm region.

Antigen-presenting function of the TL antigen and mouse CD1 molecules

The hallmark of all the nonclassical antigen-presenting molecules, including nonclassical class I and nonclassical class II (Karlsson et al. 1992) molecules, is their lack of polymorphism. It is presumed, therefore, that these nonclassical molecules must have a distinct antigen-presenting function in which polymorphism is not advantageous. In some cases this may involve presentation of a nonpeptide antigen, as has been demonstrated for human CD1b. It is possible that a molecule adapted to present bacterial lipids would remain relatively nonpolymorphic, because a lipid, which is the end product of a complex biosynthetic pathway, is likely to evolve less rapidly than a short stretch of amino acid sequence containing a T-cell epitope. Alternatively, the lack of polymorphism could reflect the presentation by these molecules of relatively invariant peptides, such as those derived from heat shock proteins. It also is possible that a nonpolymorphic molecule could be selected for the presentation of modified peptides. An example of this is the M3 molecule, which can bind even short peptides as long as they have a formylated N-terminus (Fischer Lindahl et al. 1991). Based upon their structural differences, we believe it is likely that the TL antigen and mCD1 are likely to present different types of ligands. The presence in the TL antigen of the conserved amino acids, which in class I normally from hydrogen bonds with peptides, suggests that the TL antigen also can present nanomeric peptides. A peptide antigen-presenting function also is suggested by the expression of the TL antigen by at least one antigen-presenting cell type, the epithelial cell of the intestine, and by the ability of alloreactive T cells to recognize the TL molecule. While we favor the hypothesis that the TL antigen presents peptides, the data cited above do not constitute formal proof of any kind of antigen-presenting function, and it remains possible that the TL antigen does something else. As noted above, no attempts to elucidate the structure of the ligands bound to the TL antigen have so far succeeded, including the screening of bacteriophage display libraries (Castaño, A.R., Miller, J.E., Holcombe, H.R., unpublished data). In contrast, our recent work has demonstrated that mCD1 presents relatively long peptides with a structured motif distinct from classical class I molecules. This mCD1-binding motif, which is present in a wide range of proteins, does not by itself provide a simple explanation for the lack of mCD1 polymorphism and, as noted above, it remains possible that the natural ligand for mCD1 is a nonpeptide structure. Besides their lack of polymorphism, the TL antigen and mCD1 molecules share two additional features in common which might give insight into their their biological role. First, their surface expression does not depend upon the presence of a functional TAP transporter, and they probably can reach the cell surface as empty molecules. Second, both molecules are expressed by epithelial cells in the intestine. This leads to the speculation that these two nonclassical class I molecules could be involved in sampling or uptake of lumenal peptides for their ultimate presentation to cells of the systematic immune system. For example, longer lumenal peptides could be taken up by mCD1, and perhaps by the TL antigen, and then further processed to nonamers for presentation by classical class I molecules. They also could be transported across the epithelial cell by the TL antigen or mCD1 and subsequently presented by either class I or class II molecules expressed by cells in the lamina propria. This sampling or uptake mediated by either the TL antigen or mCD1 could play a role in the induction of immune responses, or more likely perhaps, in the induction of systemic oral tolerance to peptide antigens.(ABSTRACT TRUNCATED)

Peptide binding and presentation by mouse CD1

CD1 molecules are distantly related to the major histocompatibility complex (MHC) class I proteins. They are of unknown function. Screening random peptide phage display libraries with soluble empty mouse CD1 (mCD1) identified a peptide binding motif. It consists of three anchor positions occupied by aromatic or bulky hydrophobic amino acids. Equilibrium binding studies demonstrated that mCD1 binds peptides containing the appropriate motif with relatively high affinity. However, in contrast to classical MHC class I molecules, strong binding to mCD1 required relatively long peptides. Peptide-specific, mCD1-restricted T cell responses can be raised, which suggests that the findings are of immunological significance.

Village trial of bednets impregnated with wash-resistant permethrin compared with other pyrethroid formulations

A village-scale field trial of pyrethroid-impregnated mosquito nets was undertaken in The Gambia, West Africa, in the Mandinka village of Saruja (13 degrees 13'N, 14 degrees 55'W) during July-November 1989. Nearly all the villagers possessed and used their own bednets. Anopheles gambiae is the main vector of human malaria in the area. An experimental wash-resistant formulation of permethrin was compared with standard emulsifiable concentrate (EC) formulations of permethrin and lambda-cyhalothrin, versus placebo-treated bednets. Target concentrations of pyrethroids on bednets were permethrin 500 mg/m2 and lambda-cyhalothrin 25 mg/m2. The experimental design involved random allocation of a treatment to one net per family. Whereas 68% of people questioned said they washed their nets fortnightly, observations during the 16-week trial period showed that only 4/130 (3%) of nets involved in the trial had been washed as frequently as once per month. Early morning searches for mosquitoes under bednets (1 day/week for 16 weeks) found significantly more mosquitoes (60% An.gambiae) in placebo-treated nets than in pyrethroid-treated nets. The numbers found with each of the three pyrethroid treatments did not differ significantly from each other. Insecticidal efficacy of the treatments was tested by bioassays using wild-caught unfed mosquitoes exposed to netting for 3 min. Linear regression analysis of bioassay mortality against number of times that a net had been washed by villagers showed that nets impregnated with the wash-resistant permethrin retained their insecticidal properties better than nets impregnated with lambda-cyhalothrin or with the standard permethrin formulation.

Characterization of 24-h cortisol release in obese and non-obese hyperandrogenic women

Excessive androgen output is a well-recognized feature of adrenocortical oversecretion in women with ovarian hyperandrogenism, or polycystic ovary disease (PCOD). However, evidence of a concomitant alteration of cortisol secretion is lacking even though obesity per se, a common clinical feature of PCOD, has been shown to be associated with cortisol oversecretion. To clarify whether a subtle alteration in cortisol secretion exists, a study of 24-h episodic cortisol release and post-prandial cortisol responses was undertaken in eight women with PCOD and eight normal women comprising equal numbers of obese and non-obese subjects. All four groups showed normal biphasic 24-h cortisol secretion profiles but cortisol pulse frequency was increased in the PCOD groups. Independently, both hyperandrogenism and obesity were associated with an accelerated cortisol clearance rate. These changes, together with normal or only slightly elevated 24-h cortisol integrated area under the curve, suggest an increased compensatory cortisol production in women with PCOD. Furthermore, subjects with PCOD and subjects with obesity showed different post-prandial cortisol responses to normal non-obese women. In conclusion, these subtle cortisol abnormalities may be a manifestation of altered central regulation of the hypothalamic-pituitary-adrenal axis and peripheral metabolic abnormalities, and may be linked to the pathophysiology of PCOD.

A superfamily of S locus-related sequences in Arabidopsis: diverse structures and expression patterns

Six sequences that are closely related to the S gene family of the largely self-incompatible Brassica species have been identified in self-fertilizing Arabidopsis. The sequences define four genomic regions that map to chromosomes 1 and 3. Of the four functional genes identified, only the previously reported Arabidopsis AtS1 gene was expressed specifically in papillar cells and may function in pollination. The remaining three genes, including two novel genes designated ARK2 and ARK3, encode putative receptor-like serine/threonine protein kinases that are expressed predominantly in vegetative tissues. ARK2 promoter activity was detected exclusively in above-ground tissues, specifically in cotyledons, leaves, and sepals, in correlation with the maturation of these structures. ARK3 promoter activity was detected in roots as well as above-ground tissues but was limited to small groups of cells in the root-hypocotyl transition zone and at the base of lateral roots, axillary buds, and pedicels. The nonoverlapping patterns of expression of the ARK genes and the divergence of their sequences, particularly in their predicted extracellular domains, suggest that these genes perform nonredundant functions in specific aspects of development or growth of the plant body.

Ivermectin resistant Haemonchus contortus in Louisiana lambs

Fifteen weaned crossbred (Suffolk x Louisiana Native) lambs were treated with albendazole (10 mg kg-1) to remove existing nematode infections. They were inoculated with Haemonchus contortus infective larvae from a residual population surviving treatment with the oral formulation of ivermectin (0.2 mg kg-1). One group of five lambs remained untreated, another group of five was treated with the injectable formulation of ivermectin (0.2 mg kg-1), and a third group of five was treated with the oral formulation of ivermectin (0.2 mg kg-1). Subsequent to the treatments, there was essentially no difference in mean fecal egg count or mean number of H. contortus recovered at necropsy between the three groups.

Validation of a flow cytometric in vitro DNA repair (UDS) assay in rat hepatocytes

An in vitro flow cytometric (FCM) DNA repair assay has been developed and validated by comparison to conventional autoradiography (ARG). Both assays measure unscheduled DNA synthesis (UDS). Cultures of hepatocytes from young male Sprague-Dawley rats were exposed to a battery of 26 chemicals plus bromodeoxyuridine (BrdUrd) or 3H-thymidine (3H-dT) for 18-20 h before harvest. Selection of test chemicals was based upon both their genotoxicity classifications and carcinogenicity bioassay results in male rats. DNA repair in chemically treated cultures was detected flow cytometrically by measuring the uptake of BrdUrd in non-replicating (G1, G2, mitotic and 4C) cells. Intracellular levels of incorporated BrdUrd were visualized by immunochemical labeling with fluorescein isothiocyanate (FITC), and total cellular DNA content was simultaneously estimated by counterstaining samples with the nucleic acid intercalator, propidium iodide (PI). Information was obtained from 10(4) cells/sample. Since repairing cells incorporate significantly less BrdUrd per unit of time than replicating cells, low intensity BrdUrd-FITC fluorescent signals from repairing cells are readily discriminated from high intensity signals from replicating cells when displayed on linear univariate histograms. Further distinction between repairing and replicating cells was achieved by displaying the DNA contents of all cells on linear bivariate histograms. Thus, repairing cells were resolved without subjecting these cultures to agents which suppress replicative synthesis (e.g., hydroxyurea). Results from these concurrent FCM and ARG investigations include the following: (1) conclusions (DNA repair positive or negative) were in agreement, with one exception, cinnamyl anthranilate, for which cytotoxic doses produced a positive FCM response, but lack of intact hepatocytes in parallel ARG preparations prevented analysis; (2) similar sensitivities for most of the positive chemicals were reported; (3) a high correlation (85%) exists between the reported genotoxicity classification and these DNA repair results in the absence of overt cytotoxicity; (4) a poor correlation exists between these DNA repair results and hepatocarcinogenesis (only 4/11 liver carcinogens tested positive) or overall carcinogenesis in the male rat (only 9/21 carcinogens tested positive). This FCM assay provides a rapid, sensitive, safe and reliable means of identifying agents which induce DNA repair in mammalian cells.

Poverty and children's nutritional status in the United States

This study describes deficits in nutritional status among poor children in the United States using data from the National Longitudinal Survey of Youth for children born between 1979 and 1988. The prevalence of low height-for-age (stunting) and low weight-for-height (wasting) is higher among children in persistently poor families. Differentials appear greater according to long-term rather than short-term income; hence, single-year income measures do not adequately capture the effects of persistent poverty on children's nutritional status. Differences in nutritional status between poor and nonpoor children remain large even when controls for other characteristics associated with poverty, such as low maternal educational attainment, single-parent family structure, young maternal age, low maternal academic ability, and minority racial identification, are included. The excess risks of stunting and wasting among poor children are not reduced appreciably when size of the infant at birth or mother's height and weight are controlled.

Development of the cerebellar defect in ataxic SELH/Bc mice

In SELH/Bc mice, 5-10% of young adults are ataxic, due to a midline cleft in the cerebellum. An additional 10-20% of SELH/Bc embryos have exencephaly and die at birth. All SELH/Bc embryos omit a normal step in cranial neural tube closure, initiation of fusion at Closure 2. In the 80-90% that complete cranial neural tube closure, the last region of closure, on late D9, is the region of the prospective cerebellum, and its closure is late. We postulated that the cleft cerebellum in ataxic SELH/Bc mice derives from this delay in neural tube closure and predicted that we would see evidence of a cerebellar midline cleft in all earlier stages after cranial neural tube closure is normally complete. In the present study we show that the cerebellum is cleft in a 7-9% proportion of SELH/Bc D16 fetuses (2/28) and D11 embryos (15/167), and that the defect is detectable on D10. In these abnormal D16 fetuses, D11 and D10 embryos, there is a gap in midline continuity of cerebellar neuroepithelium, a finding consistent with our hypothesis that the neuroepithelium in this region fails to complete fusion in those embryos. We also show that cerebella of adult SELH/Bc ataxic mice have no obvious deficiency of lobules, or disorganization of tissue as in the Wnt-1 mutants.

Birth order, interpregnancy interval and birth outcomes among Filipino infants

This study examines the effects of birth order and interpregnancy interval on birthweight, gestational age, weight-for-gestational age, infant length, and weight-for-length in a sample of 2063 births from a longitudinal study in the Philippines. First births are the most disadvantaged of any birth order/spacing group. The risks associated with short intervals (< 6 months) and high birth order (fifth or higher) are confined to infants who have both attributes; there is no excess risk associated with short previous intervals among lower-order infants, nor for high birth order infants conceived after longer intervals. This pattern is observed for all five birth outcomes and neonatal mortality, and persists in models that control for mother's age, education, smoking, family health history and nutritional status. Since fewer than 2% of births are both short interval and high birth order, the potential reduction in the incidence of low birthweight or neonatal mortality from avoiding this category of high-risk births is quite small (1-2%).

Behavioral response of host-seeking mosquitoes (Diptera: Culicidae) to insecticide-impregnated bed netting: a new approach to insecticide bioassays

The response of Anopheles gambiae Giles s.s and Culex quinquefasciatus Say to insecticide-treated netting in a wind tunnel permeated with guinea pig odors was recorded on videotape. With no insecticide present, mosquitoes spent 99% of the time on the netting, either at rest or occasionally walking across it. On nylon netting, permethrin at 50, 400, and 1,000 mg m-2 irritated the mosquitoes, causing them to spend significantly more time away from the netting and relatively more time walking than at rest when they were on the netting. These effects increased with dose, but the total contact time was always enough to cause 100% mortality. At the two highest doses, knockdown occurred before the end of the 10-min observation period. A wash-resistant formulation of permethrin (ICI patent) reduced irritancy without affecting mortality or knockdown. A mixture of pirimiphos-methyl and permethrin also was less irritating than permethrin alone. Pirimiphos-methyl at 400 mg m-2 was the least irritating of all treatments tested. Lambda-cyhalothrin at 2.5, 6, and 25 mg m-2 was less irritating than permethrin, even though the doses of lambda-cyhalothrin used were far more toxic than the permethrin doses as measured by LT50. Cotton netting significantly reduced the toxicity and irritancy of the permethrin treatments. Cx. quinquefasciatus was less irritated by permethrin but more irritated by lambda-cyhalothrin, than was An. gambiae. Our study indicated that mosquitoes are so strongly attracted to a host protected by netting, they will tolerate relatively high doses of irritating insecticides long enough to pick up lethal doses.

IgG antibodies from patients with bullous pemphigoid bind to fusion proteins encoded by BPAg1 cDNA

Bullous pemphigoid (BP) is an autoimmune blistering skin disease characterized in part by the presence of circulating and tissue-bound IgG antibodies directed against the epidermal basement membrane zone. IgG from over 95% of patients with BP have been shown to immunoprecipitate a 230-kD epidermal protein, BPAg1, which has been cloned and sequenced. Although sera from almost all patients with BP react with the 230-kD BP antigen the specific epitope(s) of BPAg1 that IgG binds is not known. We have generated fusion proteins from the 230-kD BP antigen cDNA and analyzed sera from patients with BP for binding to these fusion proteins by immunoblot. Sera from 21 of 30 (70%) patients with BP reacted with FP3A (amino acid 873-1193) compared to four of 13 (30%) normal subjects (p < 0.02). Sera from 10 of 30 (33%) patients reacted with FP7 (AA1623-1812) and to FP3 (AA1003-1193), compared to one of 22 (5%) and 0 of 19 (0%) controls, respectively. No significant reactivity was noted against two other fusion proteins (FP6, FP9). Twenty-four of 30 (80%) patients with BP reacted to at least one of three fusion proteins (FP3, FP3A, FP7) compared to three of 11 (27%) of the control subjects (p < 0.003). Fusion proteins FP3, FP3A, and FP7 are at the amino- or carboxyl-terminal regions of the putative central alpha-helical coiled-coil rod domain of BPAg1, which has been postulated to be involved in the self-aggregation of BPAg1. These findings demonstrate that patients with bullous pemphigoid react with multiple regions of BPAg1 and suggest that part of the pathologic consequences of these auto-antibodies in patients with bullous pemphigoid may be by the disruption of the normal self-aggregation of the BPAg1.