Contaminant Organism Growth in Febrile Infants at Low Risk for Invasive Bacterial Infection

In this multicenter, cross-sectional, secondary analysis of 4042 low-risk febrile infants, nearly 10% had a contaminated culture obtained during their evaluation (4.9% of blood cultures, 5.0% of urine cultures, and 1.8% of cerebrospinal fluid cultures). Our findings have important implications for improving sterile technique and reducing unnecessary cultures.

Predictors of Invasive Bacterial Infection in Febrile Infants Aged 2 to 6 Months in the Emergency Department

Our goal was to identify predictors of invasive bacterial infection (ie, bacteremia and bacterial meningitis) in febrile infants aged 2-6 months. In our multicenter retrospective cohort, older age and lower temperature identified infants at low risk for invasive bacterial infection who could safely avoid routine testing.

Race, Ethnicity, Language, and the Treatment of Low-Risk Febrile Infants

Importance

Febrile infants at low risk of invasive bacterial infections are unlikely to benefit from lumbar puncture, antibiotics, or hospitalization, yet these are commonly performed. It is not known if there are differences in management by race, ethnicity, or language.

Objective

To investigate associations between race, ethnicity, and language and additional interventions (lumbar puncture, empirical antibiotics, and hospitalization) in well-appearing febrile infants at low risk of invasive bacterial infection.

Design, Setting, and Participants

This was a multicenter retrospective cross-sectional analysis of infants receiving emergency department care between January 1, 2018, and December 31, 2019. Data were analyzed from December 2022 to July 2023. Pediatric emergency departments were determined through the Pediatric Emergency Medicine Collaborative Research Committee. Well-appearing febrile infants aged 29 to 60 days at low risk of invasive bacterial infection based on blood and urine testing were included. Data were available for 9847 infants, and 4042 were included following exclusions for ill appearance, medical history, and diagnosis of a focal infectious source.

Exposures

Infant race and ethnicity (non-Hispanic Black, Hispanic, non-Hispanic White, and other race or ethnicity) and language used for medical care (English and language other than English).

Main Outcomes and Measures

The primary outcome was receipt of at least 1 of lumbar puncture, empirical antibiotics, or hospitalization. We performed bivariate and multivariable logistic regression with sum contrasts for comparisons. Individual components were assessed as secondary outcomes.

Results

Across 34 sites, 4042 infants (median [IQR] age, 45 [38-53] days; 1561 [44.4% of the 3516 without missing sex] female; 612 [15.1%] non-Hispanic Black, 1054 [26.1%] Hispanic, 1741 [43.1%] non-Hispanic White, and 352 [9.1%] other race or ethnicity; 3555 [88.0%] English and 463 [12.0%] language other than English) met inclusion criteria. The primary outcome occurred in 969 infants (24%). Race and ethnicity were not associated with the primary composite outcome. Compared to the grand mean, infants of families that use a language other than English had higher odds of the primary outcome (adjusted odds ratio [aOR]; 1.16; 95% CI, 1.01-1.33). In secondary analyses, Hispanic infants, compared to the grand mean, had lower odds of hospital admission (aOR, 0.76; 95% CI, 0.63-0.93). Compared to the grand mean, infants of families that use a language other than English had higher odds of hospital admission (aOR, 1.08; 95% CI, 1.08-1.46).

Conclusions and Relevance

Among low-risk febrile infants, language used for medical care was associated with the use of at least 1 nonindicated intervention, but race and ethnicity were not. Secondary analyses highlight the complex intersectionality of race, ethnicity, language, and health inequity. As inequitable care may be influenced by communication barriers, new guidelines that emphasize patient-centered communication may create disparities if not implemented with specific attention to equity.

The Champagne Tap: Time to Pop the Cork?

BACKGROUND

A "champagne tap" is a lumbar puncture with no cerebrospinal fluid (CSF) red blood cells (RBCs). Clinicians disagree whether the absence of CSF white blood cells (WBCs) is also required.

AIMS

As supervising providers frequently reward trainees after a champagne tap, we investigated how varying the definition impacted the frequency of trainee accolades.

MATERIALS & METHODS

We performed a secondary analysis of a retrospective cross-sectional study of infants ≤60 days of age who had a CSF culture performed in the emergency department (ED) at one of 20 centers participating in a Pediatric Emergency Medicine Collaborative Research Committee (PEM CRC) endorsed study. Our primary outcomes were a champagne tap defined by either a CSF RBC count of 0 cells/mm³ regardless of CSF WBC count or both CSF RBC and WBC counts of 0 cells/mm³ .

RESULTS

Of the 23,618 eligible encounters, 20,358 (86.2%) had both a CSF RBC and WBC count obtained. Overall, 3,147 (13.3%) had a CSF RBC count of 0 cells/mm³ and 377 (1.6%) had both CSF WBC and RBC counts of 0 cells/mm³ (relative rate 8.35, 95% confidence interval 7.51 to 9.27).

CONCLUSIONS

In infants, a lumbar puncture with a CSF RBC count of 0 cells/mm³ regardless of the CSF WBC count occurred eight-times more frequently than one with both CSF WBC and RBC counts of 0 cells/mm³ . A broader champagne tap definition would allow more frequent recognition of procedural success, with the potential to foster a supportive community during medical training, potentially protecting against burnout.

Evaluation of a Mobile Health Approach to Tuberculosis Contact Tracing in Botswana

Tuberculosis (TB) contact tracing is typically conducted in resource-limited settings with paper forms, but this approach may be limited by inefficiencies in data collection, storage, and retrieval and poor data quality. In Botswana, we developed, piloted, and evaluated a mobile health (mHealth) approach to TB contact tracing that replaced the paper form-based approach for a period of six months. For both approaches, we compared the time required to complete TB contact tracing and the quality of data collected. For the mHealth approach, we also administered the Computer System Usability Questionnaire to 2 health care workers who used the new approach, and we identified and addressed operational considerations for implementation. Compared to the paper form-based approach, the mHealth approach reduced the median time required to complete TB contact tracing and improved data quality. The mHealth approach also had favorable overall rating, system usefulness, information quality, and interface quality scores on the Computer System Usability Questionnaire. Overall, the mHealth approach to TB contact tracing improved on the paper form-based approach used in Botswana. This new approach may similarly benefit TB contact tracing efforts in other resource-limited settings.

Impact of renal function and protein intake on blood urea nitrogen in preterm infants in the first 3 weeks of life

OBJECTIVE

To examine the relationship between blood urea nitrogen (BUN) during the first 3 weeks of life and protein intake and creatinine (Cr) and to quantify the effect of protein intake on postnatal growth in preterm infants.

STUDY DESIGN

This is a 4-year, single-center, retrospective cohort study. We used multivariable linear regression models to examine the relationships between mean weekly BUN and protein intake adjusted for mean weekly Cr and potential confounders. We used additional regression models to examine the effect of protein intake on growth during this period.

RESULT

Overall, 249 infants met study criteria. As protein intake increased over the first 3 weeks of life, both BUN and Cr decreased significantly. Linear regression models showed protein intake and Cr were each significantly associated with mean BUN for each study week.

CONCLUSION

Protein intake and Cr were each significantly associated with BUN. Significant amelioration of growth failure was seen with higher protein intake.

Ovulation induction and small for gestational age neonates in twin pregnancies

OBJECTIVE

To compare the incidence of small for gestation age (SGA) neonates in twin gestations conceived by ovulation induction or in vitro fertilization with that of twins conceived spontaneously.

STUDY DESIGN

A retrospective cohort study was conducted. Subjects were delivered by a single obstetric practice between 2005 and 2011 at the Mount Sinai Medical Center. Maternal and neonatal data were recorded. Our primary outcome was the incidence of SGA, defined as birth weight <10th percentile, from the three modes of conception. Chi square, ANOVA, Fisher's exact test, the Kruskal-Wallis test, the Mantel-Haenszel test, and logistic regression were used in the analysis.

RESULTS

In unadjusted analysis, using the records of 756 infants from 378 mothers of twin pregnancies, twins conceived by ovulation induction had an increased incidence of SGA (28.1%) compared to those conceived spontaneously (17.1%) and by in vitro fertilization (16.5%, p = 0.006). In a logistic regression model accounting for correlated responses between twins and adjusting for gestational age, gender, chorionicity, and maternal age, the odds ratio (95% confidence interval [CI]) of SGA for the ovulation induction group compared to the spontaneous conception group was 2.64 (1.38-5.05, p = 0.003). The odds ratio (95% CI) of SGA for the in vitro fertilization group compared to the spontaneous conception group was 1.51 (0.88-2.61, p = 0.135).

CONCLUSIONS

When adjusted for gestational age, gender, chorionicity, and maternal age, twin neonates conceived by ovulation induction, but not those conceived by in vitro fertilization, had increased odds of SGA compared to those conceived spontaneously.

A mobile health approach to tuberculosis contact tracing in resource-limited settings

Tuberculosis remains a leading cause of morbidity and mortality worldwide. In 2011, there were 8.7 million new cases and 1.4 million deaths from the disease, with &gt;95% of these deaths taking place in low- and middle-income countries [1]. Contact tracing prevents the spread of tuberculosis by identifying and screening a case's contacts and referring symptomatic individuals to health care providers. Traditionally, contact tracing has been conducted with paper forms, which can lead to considerable inefficiencies in data collection, storage, and retrieval. These inefficiencies are problematic as tuberculosis can continue to spread if disruption of disease transmission is delayed. Mobile health approaches to tuberculosis contact tracing remain largely unaddressed and limited to management and monitoring of multidrug-resistant tuberculosis [2].To address these limitations, a mobile health application that digitizes and automates contact tracing was developed. This poster presents work currently underway to evaluate this new approach in Botswana, which has the tenth highest incidence rate of tuberculosis in the world [3]. Operational considerations for implementing a mobile health approach to contact tracing in resource-limited settings are also presented.

Serological survey of Toxoplasma gondii and Campylobacter fetus fetus in sheep from New Zealand

AIM

To determine the prevalence of antibody titres to Toxoplasma gondii and Campylobacter fetus fetus in sheep from New Zealand.

METHODS

As part of a free screening service, unsolicited blood samples were supplied by veterinarians wishing to gauge the exposure of their clients' ewe flocks to T. gondii and C. fetus fetus. Blood samples were submitted from mixed-age ewes throughout New Zealand, from 2006 to 2009, that had not been vaccinated for T. gondii and C. fetus fetus. A total of 2,254 sera were serologically titrated for T. gondii and 3,429 for C. fetus fetus. A latex agglutination kit available commercially was used to quantify antibodies to T. gondii, and an agglutination test developed in-house was used for C. fetus fetus. For T. gondii, titres of ≥1:16 and ≥1:64 were used to define a positive response, and for C. fetus fetus a titre of ≥1:10 was defined as positive. A flock was defined as positive if ≥1 ewe had a positive titre.

RESULTS

Of the sera tested for T. gondii, 1,917/2,254 (85%) were positive, using a titre of ≥1:16, and 1,384/2,254 (61%) with a titre of ≥1:64. All 198 ewe flocks tested were seropositive to T. gondii, at a titre of ≥1:16, and all but three were at a titre of ≥1:64. A bimodal distribution was evident in the prevalence of titres to T. gondii suggesting that a percentage of titres ≤1:64 may have been non-specific. Of the sera tested for C. fetus fetus, 1,644/3,429 (48%) were positive to at least one of the four test antigens at titre of ≥1:10. Only 34/298 (11%) flocks tested for C. fetus fetus were completely seronegative. The percentage of seropositive ewes to both T. gondii and C. fetus fetus was significantly higher in the North Island than the South Island.

CONCLUSIONS

The study demonstrated that exposure to these two important infectious abortifacients was both considerable and widespread. Minimum titres were postulated to establish a 'cut-off' for a positive result and to allow comparison with past and future studies. The bimodal distribution evident for T. gondii suggested a titre of 1:64 may be an appropriate cut-off. The widespread on-farm exposure probably stimulates the immune response of vaccinated ewes.

CLINICAL RELEVANCE

Further studies are required to confirm the clinical significance of flock-based antibody responses, and to validate their use in identifying recently aborted ewes, especially where there are no aborted fetuses for examination.

A method to differentiate between virulent and benign isolates ofBacteroides nodosusbased on the thermal stability of their extracellular proteinases

A rapid modification of the hide powder azure proteinase degrading test was devised to distinguish between benign and virulent strains of Bucteroides nodosus grown as cultures on either liquid or solid media. The assay was based on the difference in stability, at 60 degrees C, of the enzymes released in the growth medium. The assay can be completed in four hours. Results for ovine virulent strains and their culture variants were similar and were clearly distinguishable from those of the ovine benign, bovine, deer and goat isolates which were similar to each other. The proteinase isozymes from cultures of the deer and goat isolates were separated by polyacrylamide gel electrophoresis and their molecular weights determined.

Comparison of footbathing treatments for ovine footrot using formalin or zinc sulphate

A field trial was carried out to compare 3 topical treatments for ovine footrot. They were preliminary hoof paring with weekly footbathing either in 10% formalin, or in 10% zinc sulphate + 0.2% anionic surfactant ('Teepol'), or twice-weekly footbathing in the same zinc sulphate-surfactant mixture without hoof paring. Control sheep were not treated. Within 21 days, the number and severity of active lesions of footscald and footrot among treated sheep were substantially reduced by comparison with the controls; no significant differences were observed between treatments. Treatment effects were also comparable against mild footrot infection of the sole or heel region, hut in the more advanced lesions the healing response to paring and zinc footbathing was superior to that from paring and formalin footbathing (P<0.01). Twice-weekly footbathing in zinc-surfactant solution was effective in preventing new footrot infection. No chronic toxic effects attributable to zinc sulphate at a concentration of 10% were demonstrable in the hoof integument either clinically or histologically.

Production and immunological responses associated with controlled-release-capsule vs 5-drench preventive anthelmintic programmes for parasite control in lambs

AIMS

To determine whether: a) using a controlled-release anthelmintic capsule (CRC) instead of a programme of 5 oral drenches administered at 3-4 week intervals, would delay the development of anti-parasite immunity in lambs; b) the use of ivermectin instead of albendazole, administered either as a CRC or as a programme of 5 oral drenches, would delay the development of anti-parasite immunity in lambs; c) lambs treated with CRCs would have higher liveweight gains than lambs drenched orally 5 times at 3-4 week intervals, and; d) delayed onset of anti-parasite immunity is associated with reduced liveweight gains in the period following anthelmintic treatment.

METHODS

Three field trials were conducted, 1 on a research farm and 2 on commercial sheep farms, in which groups of 30 lambs were treated with either a CRC containing albendazole, a CRC containing ivermectin, 5 oral drenches with albendazole, or 5 oral drenches with ivermectin, administered at 3-4 week intervals. Liveweights and faecal nematode egg counts (FECs) were recorded in all trials. Immunoglobulin-G (IgG) antibody levels to Ostertagia circumcincta and Trichostrongylus colubriformis adult and larval antigens were measured in Trials 1 and 3, and fleece weights and resistance of animals to nematode challenge infection were measured in Trial 1.

RESULTS

CRC-treated lambs had higher levels of antibodies to O. circumcincta infective-stage larvae (L3) than orally drenched lambs in Trial 3, but no other immunological differences due to mechanism of delivery were detected. Antibody levels were lower in lambs treated with ivermectin than albendazole, as a CRC or oral drench in Trial 1, but this was not associated with any measurable effects on FEC or productivity. No significant differences (p>0.05) were detected between drench types (albendazole vs ivermectin) or delivery mechanisms (CRC vs oral drenching) in any of the production parameters measured, in any of the trials. Albendazole-CRCs failed to control FECs in all 3 trials.

CONCLUSIONS

Although some differences between treatments in antibody levels were detected these were not associated with measurable differences in level of parasitism or productivity of lambs. CRC use did not appear to offer substantial gains in productivity over a structured programme of 5 oral drenches administered at 3-4 week intervals.

Identification of an abundant allergen from the sheep louse, Bovicola ovis

Infestation of sheep with the louse Bovicola ovis is common worldwide and leads to an allergic dermatitis referred to as 'scatter cockle'. IgE from an infested lamb was used in immunoaffinity chromatography to purify allergens from crude preparations of whole B. ovis and its faeces. SDS-PAGE of the affinity-purified eluates from both preparations showed a dominant band with M(r) of 28.5 kDa. Spleen cells from a mouse immunised with B. ovis faecal antigens were used to produce hybridomas which were screened by ELISA to identify those producing monoclonal antibodies (mAb) to the allergens purified by IgE immunoaffinity chromatography. Western blotting demonstrated that all of the mAbs examined recognised the 28.5 kDa allergen. The allergen, purified using immunoaffinity columns constructed with one of the specific mAbs, was shown to cause immediate and late-phase responses on intradermal skin testing in B. ovis-infested but not in naïve lambs. Levels of serum IgE specific for the purified allergen were significantly higher in infested than in naïve lambs (P < or = 0.0025). N-terminal and internal amino acid (aa) sequences obtained from the purified 28.5 kDa allergen were used to design primers to amplify a partial cDNA probe from B. ovis cDNA by PCR. The amplified probe was radiolabeled and used to screen a B. ovis cDNA library. The complete nucleotide sequence of the allergen was determined from the sequences of the positive clones from the library. The full-length cDNA encodes a 255 aa protein including a secretory leader sequence of 26 aas and a mature protein of 229 aas. The encoded protein showed strong homology to several hypothetical proteins of unknown function from diverse species and weak homology with lipid-binding proteins of Xenopus tropicalis and Galleria mellonella. This is the first allergen to be identified from a louse and it has been designated Bov o 1 in accordance with the criteria of the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Subcommittee.

The impact of components of fine particulate matter on cardiovascular mortality in susceptible subpopulations

BACKGROUND

Several studies have demonstrated associations between daily mortality and ambient particulate matter less than 2.5 microns in diameter (fine particles or PM2.5). Few, however, have examined the relative toxicities of PM2.5 constituents, including elemental carbon and organic carbon (EC and OC, respectively), nitrates and transition metals. There is also little information about whether associations between PM2.5 constituents and mortality are modified by socioeconomic and demographic factors.

AIM

To examine associations of daily cardiovascular mortality with PM2.5 and its constituents after stratification by gender, race/ethnicity and education, using data from six California counties during 2000 to 2003.

METHODS

The association of daily counts of cardiovascular mortality with PM2.5 components was analysed using time-series regression analyses. Poisson models with natural splines were used to control for time-varying covariates such as season and weather. Separate models were run after stratification by gender, race/ethnicity (White, Hispanic, Black) and education (high school graduation or not). Models were run for each county and results were combined using random effects meta-analysis.

RESULTS

Daily counts of cardiovascular mortality were associated with PM2.5 and several of its species including EC, OC, nitrates, sulphates, potassium, copper and iron. For many of these species, there were significantly higher effect estimates among those with lower educational attainment and Hispanic individuals. For example, while essentially no association was observed for individuals who graduated from high school, an interquartile change in several of the components of PM2.5 was associated with a 3-5% increase in daily mortality among non-high school graduates.

CONCLUSION

There is evidence that several PM2.5 constituents may represent important contributors to cardiovascular mortality. Many of these constituents are generated by motor vehicles, especially those with diesel engines, and by residential wood combustion. In addition, factors associated with low educational attainment may increase susceptibility to PM2.5 and its components.

Heritability of resistance to infestation with the body louse, Bovicola ovis, in Romney sheep bred for differences in resistance or resilience to gastro-intestinal nematode parasites

The inheritance of resistance to louse infestation and the related allergic skin disease, cockle, was examined in Romney lambs. The lambs used in the study were the 2001- and 2004-born progeny of four experimental breeding lines ("Resistant", "Susceptible", "Resilient" and "Control") developed as part of a long-term study of the genetics of host resistance (maintenance of low faecal egg count (FEC) under nematode challenge) or resilience (maintenance of health and productivity under nematode challenge irrespective of FEC) to nematode parasites in sheep. Between 13 and 22 progeny (equally distributed between males and females, where possible) from each of five sires in each line were selected each year for this trial. All lambs (n=701) were examined for lice (Bovicola ovis) before artificial infestation; in 2001 the lambs were free of natural infestation, whilst in 2004 naturally acquired infestation was evident. In November 2001 and May 2002, approximately 60 B. ovis were transferred to each lamb, followed by monitoring at approximately 2-monthly intervals until August 2002. Similar procedures, but with fewer monitoring times, were repeated on the 2004 lambs. Overall, lambs in the Control line were significantly more susceptible to louse infestation and cockle compared with those in the other three lines (P<0.001). Least squares-means (SEM) of log-transformed louse score for the control, resistant, susceptible and resilient lines, respectively, were 2.178 (0.045), 1.499 (0.050), 1.618 (0.050) and 1.587 (0.044), and for cockle score were 1.36 (0.05), 0.76 (0.05), 0.95 (0.05) and 0.78 (0.05). From all progeny together, the heritability of log-transformed louse score was 0.22 (Standard Error (SE) 0.06) in autumn and 0.34 (SE 0.08) in winter, with a value of 0.44 (SE 0.09) when these data were combined. These estimates were similar to those obtained for resistance to gastro-intestinal nematodes in these breeding lines, using log-transformed FECs. Heritability estimates for cockle score in autumn, winter and when combined were 0.06 (SE 0.04), 0.45 (SE 0.09) and 0.40 (SE 0.09), respectively. The genetic correlations of mean log-transformed louse score with mean cockle score and levels of two different louse antigens in wool were, respectively, 0.97 (SE 0.04), 0.96 (SE 0.08) and 0.95 (SE 0.09). However, there was no significant genetic correlation between louse scores and FEC. These results suggest that selective breeding would be effective in reducing louse infestation and cockle in sheep, but that differences in louse burdens were not related to differences in nematode burdens as indicated by FECs.

The transfer of maternal IgE and other immunoglobulins specific for Trichostrongylus colubriformis larval excretory/secretory product to the neonatal lamb

The transference of immunoglobulins from six New Zealand Romney ewes to their lambs was examined. Immunoglobulin levels were determined in ewe plasma, colostrum and lamb plasma shortly after birth and before the lambs fed, in lamb plasma 2 days after birth, and lamb plasma, ewe plasma and milk 30 days after parturition. Levels of total IgE, and IgE, IgG1, IgG2, IgM, and IgA with specificity for Trichostronglus colubriformis third stage larval secretory/excretory products (TcL3E/S) were determined. Mean levels of total IgE were three times higher in colostrum than in parturient ewe plasma while only trace amounts were detected in milk at 30 days after birth (107.7, 34.3, and 0.2U ml(-1), respectively, differences between means P< or =0.01). Mean total IgE in lamb plasma rose from being undetectable before suckling to levels comparable to those of the ewes by 2 days after birth (21.7U ml(-1)) and then declined to low levels by 30 days (0.4U ml(-1)). Total IgE levels in lamb plasma were significantly correlated with levels in ewe plasma and colostrum (r=0.91, P< or =0.01; r=0.96, P< or =0.003, respectively). The transference of TcL3E/S-specific IgE, IgG1 and IgA was substantial with mean levels of these antibodies in lamb plasma at 2 days comparable to that in parturient ewe plasma (absorbance levels in lamb plasma of 0.283, 0.537, and 0.334, respectively). Proportionally less maternal IgM and IgG2 appeared to be transferred to the lambs (absorbance of 0.112 and 0.081, respectively). Levels of TcL3E/S-specific IgE and IgG1 in lamb plasma at 2 days were significantly correlated with levels in parturient ewe plasma and colostrum (r=0.89 and 0.82, 0.85 and 0.96; all P< or =0.05, respectively). These results indicate that IgE is concentrated in ewe colostrum and that substantial amounts of maternal IgE are transferred to lambs via colostrum. Further, the results suggest that humoral immunity against gastro-intestinal nematode parasites and potentially other parasites in colostrum-fed lambs may approximate that of the ewe. The implications of the transference of humoral immunity through colostrum in ruminants for the passive protection and the development of active immunity against parasites remains to be fully explored.

Nonfatal Occupational Injury Among California Farm Operators

We conducted a population-based telephone survey addressing farm-work-related (FWR) injuries among California farm operators. Of 1947 participants (80.4% response), 135 farm operators reported 160 FWR injuries in the preceding year, yielding a one-year cumulative incidence for any FWR injury of 6.9% (95% CI 5.8%-8.2%), or a mean 8.2 FWR injuries per 100 farmers in the preceding year (95% CI 6.8-9.7). Multiple injury events in the same individual occurred more frequently than predicted by chance. Sprains and strains (29.4%) were the most frequently reported injury and predominantly involved the back. Overexertion represented the most frequent external cause (24.2%), followed by machinery (14.3%), falls (13.0%), and animals (12.4%). Factors associated with FWR injury included white ethnicity (OR 3.19; 95% CI 1.38-7.36), increased annual hours worked on the farm, low levels of administrative work, and increased percentage of time working with livestock. FWR injury experience of California farm operators is comparable with that reported for other agricultural populations. Above-expected frequency of multiple injuries supports involvement of personal or environmental risk factors. Preventive efforts should focus on higher-risk groups and preventing overexertion and muscle strain and injury related to machinery, falls, and animals, especially livestock.

The contribution of cytologic imprints of stereotactically guided core needle biopsies of the breast in the management of patients with mammographic abnormalities

Between 1995 and 1996, 96 consecutive patients with nonpalpable breast lesions detected by abnormal mammogram underwent core needle biopsies under stereotactic guidance at Johns Hopkins Bayview Medical Center. The cytologic diagnoses rendered on touch imprints and the histopathologic diagnoses made on the core needle biopsies were retrospectively reviewed to ascertain the accuracy and the validity of this procedure. These imprints were made of the cores as on-site evaluation in order to assist the radiologist. Separate diagnoses were rendered on the imprints and the cores. Follow-up excisional/open biopsies were then correlated to determine the usefulness of making touch imprints from the core needle biopsies toward the overall management of a patient with an abnormal mammogram. The core needle biopsies were obtained with a 14-gauge needle and biopsy gun. The cytologic diagnoses rendered on touch imprints and histopathologic diagnoses on core needle biopsies were compared and the concordance rate was determined. The subsequent surgical follow-up was analyzed and correlated with the imprint cytology and the core needle biopsy interpretation to ascertain the pathologic outcome. A total of 100 cases were reviewed: 4 patients had two lesions biopsied. Eighty-four cases showed complete cytohistologic correlation, that is, a high concordance rate. These 84 cases were divided into four categories: malignant (24), atypical (2), benign (55), and unsatisfactory (3). Of these concordant cases, there were 34 subsequent excisional biopsies and all except one confirmed the core needle biopsy diagnosis. The exception had a benign touch imprint and core but the excisional biopsy showed multifocal ductal carcinoma in situ. Of the 100 cases, 16 were nonconcordant (the cytologic diagnosis fell into a different category from the histologic diagnosis). Seven of these nonconcordant cases resulted in excisional biopsies and all but one showed the core diagnosis to be correct. The only exception was a case with atypical cytology and a benign core biopsy with the follow-up excision showing atypia. The rest of the nonconcordant cases with atypical imprints and benign cores had no follow-up surgery, showing that the clinicians are inclined to depend on the core biopsy diagnosis. While our study demonstrates the accuracy and concordance of cytologic touch imprints, the surgical follow-up data reveal that there does not appear to be any additive value to rendering a separate diagnosis on touch imprints of core needle biopsies.

Death as a complication of peripherally inserted central catheters in neonates

We report 2 neonatal deaths caused by cardiac tamponade related to peripherally inserted central catheters (PICCs). A total of 3 deaths were noted for 390 PICCs placed, giving an incidence of 0.76%. To determine the magnitude of neonatal death related to PICCs, directors of neonatal intensive care units in the United States were surveyed by means of a questionnaire. Myocardial perforation and pericardial effusion were reported by 29% and 43%, respectively. Deaths were attributed to PICCs by 24% of the respondents. Uniform guidelines need to be formulated to avoid this complication.

The immune response of sheep to larval challenge with Ostertagia circumcincta and O. ostertagi

One of three groups of sheep was challenged twice-weekly with infective-stage larvae (L3) of the sheep parasite O. circumcincta, another with the cattle parasite O. ostertagi while the third received no larval challenge. Positive faecal egg counts (FEC) and a rise in plasma pepsinogen levels were observed only in those animals given O. circumcincta. Anti-O. circumcincta L3 IgG titres were rapidly elevated during parasite challenge with either O. circumcincta or O. ostertagi. Throughout the experiment, no rise in anti-adult IgG titres or eosinophil numbers was observed in peripheral blood in any group. On evidence of self-cure of the trickle-infection, determined by a reduction in FEC, all groups were drenched and challenged with 15,000 O. circumcincta L3. No effect of previous challenge on parasite establishment or FEC was observed, although egg viability was significantly reduced in both groups given prior challenge. Significant differences in adult female worm length were observed between groups. Those recovered from animals previously challenged with O. circumcincta were shorter than from those given O. ostertagi which were in turn shorter than those from previously unchallenged animals. In utero egg counts were significantly lower in worms from animals previously challenged with O. circumcincta than in those from unchallenged control animals. The results indicate that a level of immunity to O. circumcincta can be conferred by exposure to O. ostertagi.

The application of statistical process control to manage global client outcomes in behavioral healthcare

Statistical process control (SPC) techniques were applied to simulate monitoring the process of outpatient service delivery at two mental health centers using data collected 23 years earlier. Clients included in this study received between two and 21 psychotherapy visits during the previously conducted evaluation study. Global outcomes for clients were derived from weekly ratings of functioning provided by the client and therapist. The self-report and therapist ratings were aggregated, then combined across visits to estimate the rate of linear change in functioning. Rates of change were plotted in a control chart format, using the moving average of two scores to estimate the range. Special causes of high variability and a downward trend were noted for all discharges at both centers. Control limits were re-estimated for the discharges following the downward trend in scores. Subsequently, the service processes supporting global client outcomes no longer varied uncontrollably. However, upon estimating specification limits for global client outcomes, it was noted that the mean level of client outcome fell below the mean specified as the target and that some discharges yielded unacceptable outcomes.

The effect of continuous drug exposure on the immune response of lambs challenged with drug-susceptible or drug-resistant nematode larvae

Groups of lambs either with or without controlled-release albendazole (ABZ) capsules (CRCs) were challenged twice weekly for 6 weeks with either drug-susceptible or drug-resistant Ostertagia circumcincta and Trichostrongylus colubriformis. Groups with and without CRCs remained unchallenged as controls. There was minimal establishment of drug-susceptible parasites of either species in those lambs with CRCs. However, drug-resistant parasites of both species established adult worm burdens in the presence of the capsules. The humoral immune response, as measured by the serum antilarval (L3) antibody (Ab) titre, was pooled for weeks 4-6 and compared for each group. With the exception of anti-T. colubriformis Ab in group 2, anti-L3 Ab titres were significantly higher in all the parasite-challenged groups as compared to the control animals. Also, with the exception of anti-resistant O. circumcincta Ab levels in the CRC-treated animals (group 5), no significant difference was observed in Ab titres between the four groups challenged with either resistant or susceptible larvae. The results demonstrate the inability of CRCs to prevent establishment of drug-resistant parasites and that immune stimulation is not inhibited by the capsules.

A health statistic for length of stay by reporting period

Managers of long-term care organizations lack usable information about patterns of stay, because the time spent by residents typically exceeds the length of reporting and reimbursement periods. Formulas for estimating lengths of stay often yield unstable estimates of long-term stays. Consequently, little insight is gained into changes that may be occurring in stay patterns as the organization adapts its service processes to shifts in markets. An alternative length of stay statistic is proposed from which patterns of stay can be more clearly discerned. Examples utilizing both simulated and field data are presented to highlight the advantages associated with the new statistic.

Phenotypic markers for selection of nematode-resistant sheep

Nematode-resistance of an animal can be defined as an enhanced natural ability, relative to its peers, to both prevent establishment of larval nematodes and evict any that do establish. These parameters are not measurable in a practical sense and consequently nematode-resistance has usually been defined in terms of low faecal nematode egg counts (FEC). Studies in New Zealand and Australia have demonstrated that nematode-resistance, as measured by FEC, has a heritability of about 0.3 in Romney and Merino sheep. However as a selection trait FEC has practical limitations and its use may incur production penalties through withholding drench treatment for prolonged periods or from a need for artificial challenge. FEC is influenced by the level and composition of a natural nematode challenge and especially the expression of the immune response. Thus immunological parameters which reflect the underlying genetic resistance could potentially be used as phenotypic markers. Ideally, a useful phenotypic marker would be easy to sample and its assay would be inexpensive and able to be automated, in addition to being strongly correlated with nematode-resistance. Results from several New Zealand trials have indicated that antibody levels (particularly IgG1) to excretory/secretory antigens of L3 nematodes such as Trichostrongylus colubriformis may meet these criteria. Levels of antibody against L3 antigens are also independent of on-farm drenching strategies. Blood eosinophil count has also been considered for use as a selection parameter but a high degree of sample variability reduces its potential. Other immunological parameters associated with nematode-resistance which have potential as phenotypic markers include serum nematode-specific IgE and products of mucosal mast cells such as proteinases. It is likely that as the critical immune responses of sheep to nematodes become more clearly defined, new immunological parameters with potential for use as phenotypic markers will be found. The definition of these immune responses will also assist in the identification and characterization of genetic markers.

The PCR typing of MHC-DRB genes in the sheep using primers for an intronic microsatellite: application to nematode parasite resistance

The strong association between polymorphisms in an intronic microsatellite and the coding sequences for (BoLA)-DRB3 genes, previously described for demonstrating alleles of class II major histocompatibility complex (MHC) in the cow, was examined in sheep to see if similar polymorphisms could be demonstrated in the DRB region of the MHC. The bovine primes LA53 and LA54, previously used to amplify the bovine DRB3 microsatellites, were used with DNA from Australian sheep, eight DRB alleles were identified by length polymorphisms of polymerase chain reaction (PCR) products amplified from the DRB microsatellite region. Incomplete amplification of both alleles was sometimes found for sheep DNA samples using bovine primers, so a modified primer (LA53b) was used, and found to amplify the microsatellite next to intron 2 of the MHC more reliably than the LA53 primer. Two additional primers (LA31 and LA32), used in amplification of the exon 2 region of bovine DRB3, were used in the sheep, and the PCR products were analysed by single-stranded conformation polymorphism (SSCP). These primers successfully amplified the variable region of the ovine DRB region coded by exon 2, and the SSCP technique demonstrated polymorphisms with sheep DNA. Family studies demonstrated the segregation of alleles, by amplification both of intronic microsatellites and of the exon 2 variable region. Close correspondence was found between the two regions for several alleles, suggesting that the intronic microsatellites were closely linked to DRB-variable region alleles. Three families of Merino sheep with different antibody responses to intestinal nematode parasites were examined. The sire group with the highest antibody levels possessed two microsatellite alleles of closely similar length (alleles 3 and 4) inherited from the sire and present in high frequency in the lambs. In contrast, the other two sires did not possess these two alleles and the alleles were in low frequency in their progeny. Further studies are required in unrelated sheep to confirm whether these two alleles are associated with resistance to nematode parasites.

Sequential cellular and humoral responses in the abomasal mucosa and blood of Romney sheep dosed with Trichostrongylus axei

Abomasal cannulae were surgically placed in 7 2-year-old New Zealand Romney sheep which had been maintained parasite-free from birth. Four of these sheep were randomly selected and dosed orally with 10,000 infective Trichostrongylus axei larvae per week for 8 weeks, while the remaining 3 sheep served as uninfected controls. Abomasal biopsy, blood and faecal samples were obtained from all sheep at regular intervals from 5 days before and until 58 days after the first infection. The sheep were then killed, worm burdens assessed and abomasal and small intestinal samples collected Faecal egg counts of all 4 dosed sheep were low and only one (No. 701) had a substantial worm burden (8400) post mortem. Overall, levels of mucosal mast cells/globule leukocytes, eosinophils, T19+ cells and larval migration inhibitory activity increased significantly in the abomasal mucosa of the dosed sheep compared to the controls. The CD4+:CD8+ cell ratio in the abomasal mucosa of the dosed sheep also increased compared to that of the controls (P = 0.06). In blood, T. axei-specific antibody (total and IgG1) and eosinophil numbers increased significantly in the dosed sheep. Mucosal cells staining for IgE (IgE+), and blood and mucosal eosinophils showed the earliest substantive increases in number followed by increases in specific serum antibody levels, numbers of mucosal cells fluorescing under UV light (UVf) and T19+ cells. The difference in the IgE+ and UVf cell responses indicated that expansion of globule leukocyte numbers lagged behind that of mucosal mast cells. The results supported the concept of CD4+ T cell help in the abomasal mucosa and defined the sequential expression of components of the immunological responses potentially mediating resistance to T. axei. In sheep No. 701, persistence of adult worms was associated with lower mucosal IgE+ cell and eosinophil responses compared with the other dosed sheep.

Immune responsiveness of nematode-resistant or susceptible Romney line-bred sheep to continuous infection with Trichostrongylus axei

Two divergent lines of Romney sheep have been selected on the basis of differences in faecal egg counts (FEC) to natural poly-generic parasite challenge in New Zealand. However, it is not known if the expression of resistance or susceptibility extends to parasitic nematodes that were not a major part of the selection challenge. To examine this, the immune response to infection with Trichostrongylus axei was examined in these sheep lines. Changes in the proportions of CD5+, CD4+, CD8+, T19+ and CD45R+ lymphocytes and parasite specific antibody titres in peripheral blood were monitored each week in six resistant and six susceptible line lambs that were maintained indoors in pens during the course of 14 weekly infections with 10,000 T. axei larvae. No difference in FEC was observed. Similarly, no significant difference in T. axei specific antibody titre between sheep lines was seen although antibody titre increased steadily from Week 4. Significant increases in the proportions of CD5+, CD4+, CD8+ and T19+ cells occurred in both resistant and susceptible line lambs during Weeks 1-4 of infection. Following peak levels, proportions of CD5+, CD4+ and CD8+ cells fell with the rate of decline of CD5+ and CD4+ cells significantly greater in the resistant line lambs. Proportions of CD45R+ cells showed significant changes with time that were the inverse of those of CD5+, CD4+ and CD8+ cells. Susceptible line lambs showed higher proportions of CD5+ and lower proportions of CD45R+ cells than resistant lambs before infection with T. axei. Overall, during infection, these differences were maintained while CD4+ and T19+ levels were higher in the susceptible line lambs.

Antibody responses of grazing alpacas (Lama pacos) in New Zealand to intestinal nematodes

Alpaca (Lama pacos) were grazed for 10 months (October 1992-June 1993) on pasture with sheep or on pasture which had been recently grazed by sheep. The alpaca, of various age groups, totalled 94 at the beginning of the experiment and during the course of the experiment 32 progeny (cria) were born, 10 in spring 1992 and 22 in autumn 1993. Serum levels of specific antibodies to excretory/secretory antigens of the third larval stage (L3) of Cooperia curticei, Ostertagia circumcincta or Trichostrongylus colubriformis and somatic antigens from adult T. colubriformis were determined at monthly intervals by ELISA. Faecal egg count and live-weight were determined monthly and fleece-weight was measured at shearing. Three days after the birth of the cria, serum antibody levels ranged from 0.46-0.85 optical density units for the L3 antigens and averaged 0.22 for the adult T. colubriformis antigen. These levels declined to 0.1-0.24 and 0.06 respectively by 2-3 months of age. Subsequently, antibody levels increased steadily to reach maximal adult levels at approximately 23-26 months. Antibody levels were negatively correlated with FEC, but positively correlated with live-weight at 7 months although at 15 months antibodies and live-weight were negatively correlated. A positive correlation was found between weight and FEC. Fleece-weight showed no correlation with antibody level, a positive correlation with weight and a negative correlation with FEC. The relationships among antibody responses, FEC, live-weight and fleece-weight observed for alpaca in this experiment suggest that antibody responses might provide a useful indicator of alpaca immuno-responsiveness and has potential for use as a parameter for selection of alpaca with reduced FEC.

Nematode burdens and immunological responses following natural challenge in Romney lambs selectively bred for low or high faecal worm egg count

Breeding lines of Romney sheep, selected as lambs for consistently low or high faecal nematode egg count (FEC) following periods of natural challenge, have been maintained at Wallaceville for some years. In order to determine the extent to which FECs in low and high genotypes reflected their ability to resist the establishment of gastro-intestinal nematode burdens, we investigated the infection status and immune responses in 8- to 9-month-old progeny of selected rams from low and high FEC breeding lines following a period of grazing without anthelmintic treatment in autumn/early winter. In each of the 2 years of the study, outcross male progeny of the two lowest FEC (LFEC) (i.e. most 'resistant') and two highest FEC (HFEC) (i.e. most 'susceptible') rams from the divergent lines were slaughtered shortly after autumn/early winter FECs had been analysed. Post-mortem worm counts and examination of intestinal histology were then undertaken. Blood samples collected before slaughter in the second year of the study were assayed to measure serum levels of Trichostrongylus colubriformis-specific antibody and immunoglobulins (IgG1 and IgM), and numbers of circulating eosinophils. Overall, correlations between pre-slaughter FEC and total trichostrongyle burdens in the lambs proved to be very high (0.91 and 0.85, respectively, for the 2 years studied). In the first year, LFEC lambs, which were shedding only 28.6% as many strongyle eggs as their HFEC counterparts at slaughter, were found to harbour 37.6% as many adult trichostrongyle worms, while in the second year, LFEC lambs, which were shedding 16.1% as many strongyle eggs as their HFEC counterparts at slaughter, were found to harbour 33.5% as many adult trichostrongyle worms. Results, particularly in the second year, confirmed that significantly fewer worms of most of the important abomasal and small intestinal nematode species which infest lambs in New Zealand (i.e. Haemonchus contortus, Ostertagia circumcincta, Cooperia curticei, Nematodirus spathiger, T. colubriformis, and Trichostrongylus vitrinus) had established in the LFEC genotypes than in their HFEC counterparts. In addition, in utero egg counts of female intestinal Trichostrongylus spp. were significantly lower in LFEC lambs than in their HFEC counterparts, indicating a reduction in fecundity of those worms which did establish. There was also some evidence of an effect of host response on the developmental composition of burdens in the case of some worm species. In relation to host responses, numbers of globule leucocytes/mucosal mast cells in the intestinal mucosa were significantly higher (P < 0.01) in LFEC lambs than in HFEC lambs in both years of the study. Numbers of connective tissue type mast cells and eosinophils in the intestinal mucosa were also significantly higher in LFEC lambs but only in the second year of the study (P < 0.01 and P < 0.05, respectively). Numbers of circulating eosinophils did not differ significantly between the genotypes. T. colubriformis-specific antibodies, IgG1 and IgM to both L3 and adult worm antigens were all significantly higher (P < 0.01 or P < 0.05) in LFEC lambs than in HFEC lambs.

Serum mast cell proteinase responses of sheep to challenge with Trichostrongylus colubriformis and the effect of dexamethasone treatment

Eight-month-old random bred Romney wethered lambs were reared nematode-free in pens and assigned to 4 groups of 5 lambs. Lambs in 2 groups were dosed orally, twice a week, with 5000 Trichostrongylus colubriformis infective larvae (L3) for the duration of the experiment. These 2 groups were treated weekly with dexamethasone (0.5 mg kg(-1) body-weight), one between days -7 and 70, the other between days 77 and 147. A third group was dosed with L3 until anthelmintic treatment on day 133. A fourth group remained uninfected throughout and served as a control group. Nematode eggs in sheep faeces (FEC) were monitored at weekly intervals. Serum samples were taken twice a week and assayed for sheep mast cell proteinase (SMCP). Serum levels of SMCP in uninfected control sheep were 459 +/- 190 pg ml(-1). Twenty-eight days after nematode dosing commenced, SMCP levels were significantly above control sheep levels and after 49 days reached a plateau level of 1154 +/- 364 pg ml(-1). The SMCP response persisted even after cessation of dosing, and SMCP levels remained significantly above control levels to the end of the experiment (day 213). Dexamethasone treatment prevented elevation of SMCP and resulted in a rapid reduction of extent SMCP levels in resistant sheep. Overall, serum levels of SMCP were significantly correlated (P<0.001) with specific anti-T. colubriformis L3 antibody in serum (r = 0.601, d.f. = 78), blood eosinophils (r = 0.609, d.f. = 78) and log(FEC+15) (r = -0.521, d.f. = 78). These results show that serum levels of SMCP correlate with other indicators of parasitism and may have potential use as a non-invasive indicator of gastrointestinal mast cell responses to nematode infection.

Communication issues in a multicomponent study of semiconductor employees

A variety of methods were used to address communication problems in the Semiconductor Health Study (SHS). The diverse employee population required investigators to consider language, ethnic, and cultural differences in planning and implementing the study design. Studies of reproductive health in the workplace raise special concerns, including the critical need to preserve confidentiality and privacy of subjects. Notification of results of epidemiological studies reporting workplace hazards requires sensitivity to needs of workers. SHS investigators directly communicated overall results of this multicomponent study to participating employees at all sites and notified subjects of results of individual industrial hygiene monitoring and endocrine hormone assays.

Historical cohort study of spontaneous abortion among fabrication workers in the Semiconductor Health Study: agent-level analysis

Risk of spontaneous abortion (SAB) was examined in relation to chemical and physical agents in a retrospective study of employees of 14 seminconductor manufacturers: After screening over 6,000 employees, 506 current and 385 former workers were eligible. If a woman had multiple eligible pregnancies, one was selected at random. Telephone interviews provided data on demographics and occupational and other exposures during the first trimester. Two groups of chemicals accounted for the 45% excess risk of SAB among fabrication-room (fab) workers: photoresist and developed solvents (PDS), including glycol ethers, and fluoride compounds used in etching. Women exposed to high levels of both these agents were at greater risk (RR = 3.21, 95% confidence interval [CI] = 1.29-5.96). In fab workers without these exposures, SAB rates were not elevated (adjusted relative risk [RR] = 0.98, 95% CI = 0.55-1.69). An association was seen with workplace stress, which was not limited to women exposed to PDS or fluoride, nor did stress explain the associations between these chemicals and SAB.

Historical cohort investigation of spontaneous abortion in the Semiconductor Health Study: epidemiologic methods and analyses of risk in fabrication overall and in fabrication work groups

The risk of spontaneous abortion (SAB) in the semiconductor industry was examined in a historical cohort study of pregnancies at 14 companies. We identified female employees who had worked for at least 6 months and whose ages ranged from 18 to 44 years during the 1986-1989 study period. Using company records, we included all fabrication-room (fab) employees and an approximately equal number of nonfabrication (nonfab) employees, for a total sample of 7,269. Telephone interviews with 6,088 women (84%) identified 904 eligible pregnancies and 113 SABs. Exposure classification was based on questionnaire and industrial hygiene assessments of tasks the women performed during the first trimester of pregnancy. Using logistic regression to control for age, smoking, ethnicity, education, income, year of pregnancy, and stress, we found a higher risk of SAB in fab employees than in nonfab employees (15.0% of fab pregnancies ended in SAB vs. 10.4% of nonfab pregnancies, adjusted relative risk [RR] = 1.43, 95% CI = 0.95-2.09). Analysis of fab work groups showed that the highest relative risk was in masking employees (17.5% SAB rate, adjusted RR = 1.78, 95% CI = 1.17-2.62 in comparison with nonfab employees). Within masking, the highest risk was found in etching-related process employees (22.2% SAB rate, adjusted RR = 2.08, 95% CI = 1.27-3.19 in comparison to nonfab employees.

The California Adult Performance Outcome Survey: preliminary evidence on reliability and validity

Recent legislation in California mandated the development of an outcome measure suitable for measuring changes in quality of life associated with treatment in the public mental health system. The measure, known as the California Adult Performance Outcome Survey (CAPOS), relies on clinician and client reports of objective and subjective indicators of quality of life. The present study sought to determine whether the clinician-administered CAPOS would agree with that administered by trained research assistants, and whether the CAPOS would agree with an established quality of life measure. A sample of sixty-four severely mentally ill subjects were assessed by their regular mental health provider using the CAPOS. One week later they were assessed by a trained research assistant using the CAPOS and Lehman's Quality of Life Interview (QOLI). For most outcome domains, the CAPOS exhibited moderate to excellent agreement across occasions and raters. Correlations with the QOLI indicated a good degree of overlap among corresponding domains. Outcome measurement procedures for routine use in clinical settings are in their infancy. The CAPOS appears promising in this role because of its brevity, ease of administration, and adequate interrater reliability. The CAPOS affords state and local mental health authorities with an efficient means of tracking key quality of life indicators within the public mental health system.

Identification of lysyl oxidase and other platelet-derived growth factor-inducible genes in vascular smooth muscle cells by differential screening

BACKGROUND

Atherosclerosis and arterial injury are characterized by vascular smooth muscle cell (VSMC) migration and growth and an increase in synthesis of extracellular matrix. Platelet-derived growth factor (PDGF) has been implicated in these processes. This study was designed to identify additional PDGF-regulated genes in VSMC.

EXPERIMENTAL DESIGN

A cDNA library prepared from PDGF-stimulated rat aortic VSMC was screened by differential hybridization to identify clones representing PDGF-inducible genes. The time course of growth factor-induced changes in gene expression was examined by RNA blot hybridization. Assays of protein activity were also performed for selected gene products.

RESULTS

Four PDGF-regulated cDNA clones were identified by DNA sequencing. These encoded the extracellular matrix proteins lysyl oxidase (LO), thrombospondin, and osteopontin and the intracellular enzyme lactate dehydrogenase (LDH). Levels of mRNA corresponding to all four genes were low in quiescent VSMC and were markedly induced by PDGF, angiotensin II, and 10% calf serum. The regulation of LO and LDH mRNA by these agonists in VSMC has not been previously reported. LO enzymatic activity in the culture media was increased by approximately equals to 700% after exposure to PDGF. In contrast, LDH activity was not increased by PDGF treatment.

CONCLUSIONS

The induction of LO mRNA and its secretion by VSMC is an early event accompanying growth factor stimulation and may contribute to organization of the extracellular matrix.

Genetic factors affecting antibody responses to four species of nematode parasite in Romney ewe lambs

Serum levels of antibodies (Ab) and immunoglobulin G1 (IgG1) to the larval (L3) stage of the internal parasites Cooperia curticei and Trichostrongylus colubriformis and levels of Ab to the L3 stages of Haemonchus contortus and Ostertagia circumcincta were determined in 1432 Romney ewe lambs which were born on one farm in 1990 and 1991 and were the progeny of 63 rams. The objectives were to estimate heritabilities of, and genetic correlations among, the serum concentrations in newly weaned lambs under commercial conditions and to estimate genetic correlations of Ab and IgG1 with production traits. Lambs were exposed to a natural parasite challenge on pasture, following an anthelmintic drench at weaning. Blood and faecal samples from 4- to 6-month-old lambs were then taken when the mean faecal nematode egg count of a monitor group reached 800-1500 eggs g-1. Heritabilities for the serum levels of the four Abs ranged from 0.25 +/- 0.05 to 0.37 +/- 0.06. Heritabilities for the level of IgG1 developed against C. curticei was 0.19 +/- 0.04 and against T. colubriformis, 0.18 +/- 0.05. Genetic correlations between Abs for the 4 species were high, averaging 0.84, and between the two IgG1s it was 0.82. The genetic correlations between Ab or IgG1 levels and weight or gain traits were negative (for the 6 significant values out of 18), with yearling fleece weight positive (for the 2 significant values out of 6), whilst those with loge faecal egg count were all negative (average -0.15).(ABSTRACT TRUNCATED AT 250 WORDS)

Variation in immune responsiveness of sheep to the antigens of intestinal nematodes and blowfly larvae

The total and IgG1 antibody responses to the intestinal nematode parasites Haemonchus contortus and Trichostrongylus colubriformis were measured in the serum of 160 lambs, 4 months of age. These antibodies had developed as the result of natural exposure to the parasites on pasture. Three sires were examined and strong sire effects on half-sib progeny were found. Plotting of ELISA antibody results in two dimensions revealed clustering of responses within sire groups. Bimodal antibody distributions were also observed within sire groups and the whole population for T. colubriformis. A bimodal distribution of antibodies to H. contortus was found for one sire group but not for the whole population. The injection of blowfly larvae (Lucilia cuprina) extract into 42/160 lambs at a later age (12 months) was followed by increased antibodies to L. cuprina and an apparent increase in antibodies to T. colubriformis. A bimodal distribution for antibodies to L. cuprina was found in one sire group and in the whole population. These bimodal distributions of antibodies to L. cuprina did not coincide with the distribution of antibodies to T. colubriformis or H. contortus, measured on the same serum samples. It was concluded that high and low responder sire groups could be differentiated in lamb populations for all three parasites. These effects persisted during lamb maturation and appeared to be genetic effects. Finally, cross-reacting antibodies between L. cuprina and T. colubriformis appear to be stimulated by injection of L. cuprina antigens.

Immunization of sheep against parasitic nematodes leads to elevated levels of globule leukocytes in the small intestine lumen

In sheep that had been given three immunizing infections with Trichostrongylus colubriformis and Ostertagia circumcincta infective (L3) larvae, drenched after the last infection and challenged with larvae of the same species, there was a significant increase in numbers of small intestine mucosal tissue globule leukocytes (TGLs) and lumenal globule leukocytes (LuGLs) compared with sheep that had only been drenched and challenged. There was a positive correlation between the numbers of LuGLs and TGLs in the small intestine but the ratio of these two cell types was lower in non-immunized than immunized sheep. In immunized sheep positive correlations were observed between LuGLs and levels of arylsulphatase and peroxidase in the intestinal mucus and between arylsulphatase and larval migration inhibition (LMI) activity in mucus. Lumen eosinophils correlated with blood eosinophils, serum antibody against T. colubriformis correlated with peroxidase in the mucus and blood eosinophils correlated with nematode specific IgM levels in the intestinal mucus. In the abomasum, TGLs were present but not LuGLs. Sheep repeatedly infected with T. axei also had significantly more LuGLs in the small intestine than control animals. Two sheep that had a surgically prepared isolated small intestinal loop, after oral infection with T. colubriformis had TGLs and LuGLs in the intact intestine, but not in the isolated loop. Significantly more LuGLs were produced in sheep by allowing repeated T. colubriformis L3 infections to develop to adult stages compared to sheep treated with the same number of larvae, but where the infections were terminated by drenching at various intervals.

Antibody responses of sheep to challenge with Trichostrongylus colubriformis and the effect of dexamethasone treatment

Eight-month-old random bred Romney wether lambs were reared nematode-free in pens and assigned to 4 groups each of 5 lambs. Lambs in 3 groups were infected orally, twice a week, with 5000 Trichostrongylus colubriformis infective larvae (L3), a control group remained unifected throughout. Two infected groups were treated with dexamethasone (0.5 mg kg-1 bodyweight), one between days -7 and 77, the other between days 77-154. Nematode challenge infection was withheld from the third group from day 133 after anthelmintic treatment. Nematode eggs in sheep faeces (FEC) were monitored at weekly intervals. T. colubriformis-specific antibody levels were determined twice a week and specific immunoglobulin isotypes (IgA, IgG1, IgG2 and IgM) determined weekly in serum samples using ELISA. Resistance, as measured by FEC, was expressed by 35 days after L3 infection began but sheep dosed with dexamethasone did not develop resistance. Extant resistance was abrogated in sheep dosed with dexamethasone. Nematode challenge resulted in elevated serum levels of antibodies to T. colubriformis L3 excretory/secretory antigens, these consisted predominantly of IgG1 and IgM. The IgG1 response was more persistent than the IgM response. Specific serum IgA and IgG2 responses were low, but significant, in nematode-challenge sheep. Dexamethasone treatment prevented the antibody responses and resulted in a rapid reduction of extant antibody levels in resistant sheep. Weight gain was reduced by nematode challenge with or without dexamethasone treatment compared with control sheep.

Cloning and expression of a novel acidic calponin isoform from rat aortic vascular smooth muscle

The actin-binding protein calponin has been implicated in the regulation of smooth muscle contraction. We have isolated cDNA clones encoding a novel acidic calponin isoform from rat aortic vascular smooth muscle cells. The initial 273 residues of the deduced 330 amino acid polypeptide (M(r) 36,377) are highly homologous to basic smooth muscle calponin isoforms, but the remaining 57 residues at the carboxyl terminus comprise a unique and strongly acidic domain. The sequence of the acidic domain shows high homology (93.3% identity) to the partial sequence of HUMXT01244, an unidentified human hippocampal gene product (Adams, M., Dubnick, M., Kerlavgne, A. R., Moreno, R., Kelly, J. M., Utterback, T. R., Nagle, J. W., Fields, C., and Venter, J. C. (1992) Nature 355, 632-634). Transcripts encoding acidic calponin are expressed in cultured rat aortic vascular smooth muscle cells and in non-muscle and smooth muscle tissues of adult rat. Based on its calculated M(r) and the tissue distribution of its expression, acidic calponin is an excellent candidate for a previously detected non-muscle calponin homolog (Takeuchi, K., Takahashi, K., Abe, M., Nishida, W., Hiwada, K., Nabeya, T., and Maruyama, K. (1991) J. Biochem. (Tokyo) 109, 311-316). Like basic calponin isoforms, acidic calponin synthesized in a bacterial expression system bound F-actin. However, unlike basic calponin, the acidic isoform did not interact with Ca2+/calmodulin, indicating a functional distinction between the muscle and non-muscle forms.

Association of blood eosinophilia with the expression of resistance in Romney lambs to nematodes

The dynamics of blood eosinophilia was studied in Romney lambs dosed twice weekly with 5000 infective larvae of Trichostrongylus colubriformis. A marked rise in blood eosinophil counts of the dosed lambs coincided with the start of the decline of faecal egg counts (FEC). Eosinophilia was also studied in grazing Romney lambs from a breeding programme, based on selection for high or low FEC. Comparison of the sire groups suggested that the magnitude of the eosinophil response was under genetic control. The significant negative correlations between blood eosinophil counts and FECs confirmed the association between eosinophilia and the expression of resistance in Romney lambs to nematodes. However, comparison of the mean blood eosinophil counts and FECs for both the ram and ewe lambs of the resistance sire groups suggested that the association of eosinophilia and resistance may be greater for some sire groups than others.

JE mRNA accumulates rapidly in aortic injury and in platelet-derived growth factor-stimulated vascular smooth muscle cells

The early response to vascular injury is characterized by migration of inflammatory cells, including monocytes, and platelets to the damaged vessel wall. These inflammatory cells may serve as a source of growth factors and cytokines that stimulate vascular smooth muscle cell (VSMC) migration and proliferation associated with intimal hyperplasia. JE is a platelet-derived growth factor (PDGF)-inducible "early" gene that encodes a monocyte chemoattractant and, as such, could play an important role in inflammation. We now report that JE mRNA levels are increased in intact aorta after balloon injury. The time course of this increase, with maximal levels at 4 hours, is similar to that seen in PDGF-treated cultured rat aortic VSMCs. The accumulation of JE mRNA in cultured VSMCs is accompanied by a marked increase in the secretion of JE protein. The elevation of JE mRNA levels in VSMCs shows specificity for PDGF, because angiotensin II, alpha-thrombin, and epidermal growth factor fail to increase JE mRNA levels. In contrast to 3T3 fibroblasts, the accumulation of JE mRNA in VSMCs in response to PDGF is predominantly due to an increase in JE mRNA stability. The accumulation of JE mRNA in VSMCs stimulated by PDGF appears to occur via a novel pathway(s) independent of Ca2+ mobilization, Na(+)-H+ exchange, protein kinase C activation, or elevation in cAMP levels. These findings suggest that VSMCs may take part in the early inflammatory response after injury through the production of JE, a potent monocyte chemoattractant. Finally, our data suggest that JE may be a marker for PDGF-specific effects on VSMCs, both in vitro and in vivo. Thus, in addition to direct effects on VSMC growth and migration, PDGF may play a role in the early inflammatory response after vascular injury by inducing chemoattractants, such as that encoded by JE.