A longitudinal study of faecal shedding of Yersinia enterocolitica and Yersinia pseudotuberculosis by Merino lambs in south-eastern Australia.

A prospective longitudinal study was conducted to investigate potential risk factors for faecal shedding of Yersinia enterocolitica and Y. pseudotuberculosis by Merino lambs in four flocks in south-eastern Australia. The primary aims of the study were to determine the seasonal patterns of shedding of pathogenic Y. enterocolitica and Y. pseudotuberculosis, and to evaluate putative risk factors for faecal shedding of these organisms, including worm egg count, live-weight and growth rate. The risk of shedding varied markedly between Yersinia spp., farms, seasons and years. Shedding of Y. pseudotuberculosis occurred predominately in winter, whereas Y. enterocolitica was commonly isolated from faeces throughout the year. Moderate to high prevalences of shedding of each organism occurred in the absence of outbreaks of yersiniosis. In general, for shedding of Y. pseudotuberculosis, animals with moderate or high worm egg counts were at increased risk of shedding compared with animals with low worm egg counts. Sheep with higher average daily weight gains were at decreased risk of shedding Y. enterocolitica but at increased risk of shedding Y. pseudotuberculosis. Live-weight was not significantly associated with risk of shedding either species. This study highlighted that exposure to determinants of shedding Y. enterocolitica and Y. pseudotuberculosis differ between farms and over time within farms. Shedding is likely influenced by environmental, animal and management factors. Our results indicate that different or additional risk factors are required for yersiniosis over those that cause faecal shedding of Yersinia spp., because moderate to high prevalences of shedding were not always associated with outbreaks of clinical disease.

The pathogenesis and control of diarrhoea and breech soiling in adult Merino sheep.

Diarrhoea and soiling of the breech with faeces ('winter scours') is a serious problem in adult Merino sheep grazing improved pastures in south-eastern Australia during winter and spring. This occurs even on farms where gastro-intestinal nematodes are effectively controlled. It was shown that winter scours was associated with the ingestion of trichostrongylid larvae, and that host factors were important in determining susceptibility to this syndrome. No differences were detected in the protective immune response of affected and unaffected sheep to gut nematodes. However, affected sheep had a hypersensitive inflammatory reaction in the pylorus and upper jejunum, characterised by the infiltration of significantly more eosinophils and changed lymphocyte populations. The changes in the lymphocyte populations included a reduced number of CD8+ cells, increased CD4+:CD8+ T-cell ratio, and significantly reduced numbers of cells reacting to interferon-gamma. High doses of infective larvae (20,000/week of Ostertagia circumcincta and Trichostrongylus vitrinus) did not induce diarrhoea in sheep not susceptible to winter scours. In contrast, only low doses (2000/week) initiated scouring in sheep selected as being susceptible to winter scours. Therefore, even considerably improved worm control programmes, including the selection of sheep with increased resistance to gut nematodes, will not prevent winter scours. Rather, phenotypic culling and genetic selection, to remove sheep susceptible to the hypersensitivity inflammatory response, is proposed as the most suitable long-term control strategy.

Balanced rearrangement of chromosomes 2, 5, and 13 in a family with duplication 5q and fetal loss.

We have studied a family in which a mother and daughter (the proposita) had the karyotype 46,XX,ins(2;5),t(5;13). The mother had four spontaneous abortions, a mentally retarded son with duplication (5q), and a daughter who died at 3 months. The proposita had a phenotypically abnormal abortus. Rearrangements involving several chromosomes are very rare. Observations on this family are consistent with the predicted high likelihood of reproductive loss.

A simple method for gross examination of the brain in abortuses and macerated fetuses.

The use of maternal serum alpha-fetoprotein screening and sonography has led to an increase in the prenatal diagnosis of major central nervous system (CNS) malformations. Therefore, it is important to correctly identify the type of malformation for proper counseling. We describe an autopsy method--freezing and sectioning of the fetal head--that should increase the accuracy of diagnosis after second-trimester abortion.

Significance of neutrophils and bacteria in the amniotic fluid of patients in labor.

Amniotic fluid specimens from 110 patients in labor were examined for neutrophils and bacteria. Patients with neutrophils in their amniotic fluid had significantly higher fever indices than patients with clear amniotic fluid. The highest fever indices were found in those patients who delivered by cesarean section after neutrophils were present in their amniotic fluid. Febrile morbidity was significantly reduced in a group of 24 such patients by giving prophylactic antibiotics.

Prevention of perinatal group B streptococcal infection: current controversies.

Group B streptococcus (GBS) is the most frequent cause of neonatal sepsis in the United States. The Centers for Disease Control and Prevention (CDC) issued guidelines for its prevention in 1996. This article details areas of controversy with those guidelines and offers recommendations for resolution. We recommend that a prevention policy be adopted by all hospitals. If a screening-based policy is chosen, compliance is essential. Penicillin is the antibiotic of choice for GBS prevention. Increasing resistance to clindamycin and erythromycin might eliminate them as alternative choices in patients allergic to penicillin. Group B streptococcal prophylaxis might not be necessary in women who have repeat elective cesarean delivery. In asymptomatic women, a positive urine culture for GBS should be considered clinically equivalent to a positive vaginal or rectal sample for screening. Neonatal sepsis caused by organisms other than GBS must be monitored carefully by all hospitals providing obstetrics services.

First-trimester Down syndrome screening using dried blood biochemistry and nuchal translucency.

OBJECTIVE: To assess the effectiveness of free beta-hCG, pregnancy-associated plasma protein A, and nuchal translucency in a prospective first-trimester prenatal screening study for Down syndrome and trisomy 18. METHODS: Risks were calculated for Down syndrome and trisomy 18 based on maternal age and biochemistry only (n = 10,251), nuchal translucency only (n = 5809), and the combination of nuchal translucency and biochemistry (n = 5809). RESULTS: The study population included 50 Down syndrome and 20 trisomy 18 cases. Nuchal translucency measurement was done on 33 Down syndrome and 13 trisomy 18 cases. Down syndrome screening using combined biochemistry and ultrasound resulted in a false-positive rate of 4.5% (95% confidence interval [CI] 3.9%, 5.2%) and detection rate of 87.5% (95% CI 47%, 100%) in patients under age 35 years. In older patients, the false-positive rate was 14.3% (95% CI 12.7%, 15. 8%) and detection rate was 92% (95% CI 74%, 99%). For trisomy 18 screening, the false-positive rate was 0.4% (95% CI 0.24%, 0.69%) and detection rate was 100% (95% CI 40%, 100%) in younger patients, whereas in older patients the false-positive rate was 1.4% (95% CI 0. 9%, 2.0%) and detection rate was 100% (95% CI 66%, 100%). Using modeling, at a fixed 5% false-positive rate, the Down syndrome detection rate was 91%. Conversely, at a fixed 70% Down syndrome detection rate, the false-positive rate was 1.4%. CONCLUSION: First-trimester screening for Down syndrome and trisomy 18 is effective and offers substantial benefits to clinicians and patients.

Penicillin treatment for group B streptococcal meningitis in the rhesus monkey.

Penicillin therapy for experimentally produced neonatal meningitis due to intracerebral inoculation of group B streptococci (GBS) was studied in 25 rhesus monkeys. Penicillin was administered either therapeutically to the newborns 3 hours after GBS inoculation or prophylactically as a bolus to the pregnant females 2 hours before delivery. The neonatal mortality in the newborn treatment groups was 40% (6 of 15) compared to 100% (5 of 5) in the maternal prophylaxis group, and 0% (0 of 5) among uninfected and untreated controls. It was concluded that although penicillin can be used successfully to treat neonates with meningitis after intracerebral inoculation of GBS, penicillin given antepartum as bolus prophylaxis to the mother monkey was ineffective.

Intraamniotic infection due to group G streptococcus: treatment and antibody response.

Penicillin treatment and antibody response were studied using a rhesus monkey model for intraamniotic infection with type III group B streptococci (T3GBS). Acute and convalescent phase sera from mothers and their offspring were tested with a radioactive antigen-binding assay to determine the concentration of antibody to the capsular T3GBS antigen. The frequency of placentitis was significantly lower in penicillin-treated animals (3 of 8) than in controls (10 of 10; P less than .01). The penicillin group also had a significantly lower neonatal mortality (1 of 9) than controls (6 of 10; P less than .05). Both groups of rhesus mothers developed a significant increase in concentration of antibody to T3GBS, but the antibody response was of lesser magnitude in the penicillin-treated group. This experimental model appears to be useful for studying both therapy for intraamniotic infection and the humoral immune response to infection with T3GBS.

Prenatal diagnosis of cystic fibrosis by chorionic villus sampling using 12 polymorphic deoxyribonucleic acid markers.

This report describes the application of a genetic prenatal diagnostic test for cystic fibrosis to a family with a cystic fibrosis-affected child. The test uses 12 deoxyribonucleic acid (DNA) markers that bracket the cystic fibrosis gene on chromosome 7, and chorionic villus tissue as a source of DNA from the fetus at risk for cystic fibrosis. The fetus was predicted by DNA analysis to be unaffected (although a carrier of one cystic fibrosis gene); this diagnosis was confirmed postnatally by the standard sweat electrolyte test. The genetic linkage test is informative in more than 99% of families with cystic fibrosis-affected members and is also useful for determination of carrier status. The test is both more informative and more accurate than one based upon the markers Met and D7S8 (J3.11) alone. The analysis can be done directly from chorionic villus tissue, and therefore can provide a diagnosis as early as nine to 12 weeks after conception.

Prenatal diagnosis of congenital adrenal hyperplasia.

In patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, the concentrations of the cortisol precursor 17-alpha hydroxyprogesterone (17-OHP) and its metabolite delta 4-androstenedione (delta 4 A) are increased. CAH was diagnosed in twins by measurement of 17-OHP and delta 4 A concentrations in amniotic fluid obtained by amniocentesis from both amniotic cavities at 17 weeks' gestation. Both prenatal karyotypes were 46,XX. Spontaneous labor and delivery of 2 nonviable fetuses with genital masculinization occurred at 26 weeks' gestation. It is concluded that delta 4 A measurement, like 17-OHP quantitation, is valuable in the prenatal diagnosis of CAH; that both methods appear useful in prediction of CAH in twin fetuses; and that abnormal adrenal-mediated masculinization in female CAH is well established before the end of the second trimester.

Efficacy and tolerability of imipenem-cilastatin versus clindamycin+gentamicin for serious pelvic infections.

A multicenter, prospective, open-label, randomized trial compared imipenem-cilastatin (I-C) monotherapy with the combination of clindamycin+gentamicin (C+G). Efficacy and tolerability in the treatment of serious pelvic infections were evaluated in 94 female patients with acute salpingitis, pelvic abscess, or postoperative pelvic cellulitis. Duration of therapy averaged 5.4 days for treatment successes and ten days for treatment failures. The overall treatment success rate was 98% (43 of 44 patients) in the I-C group, compared with 92% (46 of 50 patients) in the C+G group (P = NS). Adjunct therapy for two treatment successes in the I-C group included laparoscopy and surgical removal of a pelvic abscess without change in antibiotics. Both I-C and C+G were highly effective and generally well tolerated for the treatment of salpingitis, pelvic abscess, and postoperative pelvic cellulitis.

Comparison of cefoxitin and clindamycin-gentamicin for pelvic infections.

Cefoxitin and clindamycin-gentamicin were compared in a randomized study of antibiotic therapy for infections of the pelvis in 91 women. Clinical diagnoses included pelvic inflammatory disease (53), endomyometritis after cesarean section (24), and cellulitis following gynecological surgery (14). Treatment failures occurred in four (10%) of the 41 patients treated with cefoxitin compared with eight (16%) of the 50 patients treated with the clindamycin-gentamicin combination. Single-drug therapy with cefoxitin was shown to be as effective as the combination of clindamycin and gentamicin.

Prenatal diagnosis of fetal anomalies using ultrasound and MRI.

In conclusion, it is unlikely that MRI will replace ultrasound as the primary obstetric imaging modality in the near future. Ultrasound has a proven record of accuracy and safety in addition to its easy access and low cost. MRI has promise, however, in providing crucial information in patients with underlying medical or surgical conditions that would ordinarily require ionizing radiation for evaluation. Currently, MRI is helpful in evaluating gross fetal anomalies and disturbances of fetal growth and development when ultrasound is limited by oligohydramnios or maternal obesity. Further experience is required to determine the value of spectroscopy and quantitative relaxation times regarding fetal metabolism and fetal well-being. Technologic improvements and software updates will reduce imaging time and increase spatial resolution, thus rendering MRI more competitive with existing imaging techniques. The ultimate role, however, that MRI will have in the evaluation of the fetus is currently undefined.

Advent of maternal serum markers for Down syndrome screening.

Trisomy 21, or Down syndrome, is the most common serious autosomal chromosome aberration in which affected individuals survive beyond infancy. The association between advancing maternal age and increased risk of trisomy 21 is well known, and pregnant women older than 35 years at delivery are routinely offered invasive prenatal diagnostic testing. More recently, the use of maternal serum markers in the second trimester of pregnancy to predict the risk of trisomy 21 for women under the age of 35 has received intensive analysis. Maternal serum alpha-fetoprotein (MSAFP) was the first of these markers to be identified, and an inverse correlation between MSAFP level and risk of trisomy 21 was noted. A second marker, unconjugated estriol (uE3), has also been studied, and a correlation between low uE3 and trisomy 21 has been demonstrated, with a high level of correlation between AFP and uE3. The addition of uE3 to the screening protocol has not consistently improved detection rates, possibly because of its high correlation with AFP. A strong association of human chorionic gonadotropin (hCG) and Down syndrome was reported. This analyte is the most sensitive one in use today, although controversy exists regarding the best form of the analyte to use for trisomy 21 prediction. Several groups of investigators advocate measurement of total hCG, while others feel that measurement of the free-beta subunit of the molecule offers greater detection ability. The maximum detection rate that has been reported is 80 percent with a 5 percent false-positive rate using a combination of MSAFP, free-beta hCG, and maternal age.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of syringe toxicity to amniotic fluid cells in culture.

Toxicity to amniotic fluid from many brands of syringes has been reported in the past few years. Thirty amniocentesis samples were exposed to Becton-Dickinson syringes for varying lengths of time and evaluated for growth rate. Six amniocentesis samples were exposed to the syringes for prolonged periods at varying temperatures and also evaluated for growth rate. No evidence of syringe toxicity was found for exposure periods up to 24 h, regardless of storage temperature.

Three-dimensional computed tomography in maxillofacial surgical planning.

Fifty-four maxillofacial three-dimensional computed tomographic examinations were performed during a 12-month period for the purpose of surgical planning. Pathologic entities in the series included trauma, neoplasia, cleft palate, and other developmental anomalies. Computer-assisted mandibular disarticulation was performed routinely after each study to permit direct viewing of the mandible or maxilla in isolation. Three-dimensional computed tomography is a useful technique for maxillofacial surgical planning.

Temporomandibular joint imaging. Practical application of available technology.

Clinical afflictions of the temporomandibular joint (TMJ) are common, but TMJ afflictions remain one of the most poorly understood and controversial areas of clinical practice. Theories of TMJ pathophysiology, diagnosis, treatment, and patient disposition abound. Many afflicted patients have undergone expensive, protracted, and fruitless therapeutic endeavors, many of which are without scientific basis, causing many health insurers to exclude evaluation and treatment of TMJ disorders from coverage. Medical imaging has a central role in establishing a correct diagnosis. Available imaging procedures include roentgenography, arthrography, videofluoroscopy, magnetic resonance imaging, and computed tomography.

Automatic torque magnetometer for vacuum-to-high-pressure hydrogen environments.

An automatic torque magnetometer has been developed for use in high-pressure hydeogen. It will contain pressures ranging from vacuum to 200 atm of hydrogen gas at sample temperatures greater than 400 degrees C. This magnetometer, which uses an optical lever postion sensor and a restoring force technique has an operating range of 2.0x10(3) dyn cm to l.6x10(-4) dyn cm. An accompanying digital data collection system extends the sensitivity to 1x10(-5) dyn cm as well as increasing the data handling capacity of the system. The magnetic properties of thin films in high-temperature and high-pressure hydrogen environments can be studied using this instruments.

Postabortal septic pelvic thrombophlebitis diagnosed with computed tomography. A case report.

Septic pelvic thrombophlebitis is an uncommon complication in obstetrics and gynecology that may be difficult to diagnose clinically. Computed tomography (CT), an accurate and noninvasive modality, has greatly aided in the diagnosis of this disorder. In a case of septic pelvic thrombophlebitis complicating second-trimester pregnancy termination, CT enabled the correct diagnosis to be made and treatment to be initiated.