Biostatistical prediction of genes essential for growth of Anaplasma phagocytophilum in a human promyelocytic cell line using a random transposon mutant library.

Anaplasma phagocytophilum (Ap), agent of human anaplasmosis, is an intracellular bacterium that causes the second most common tick-borne illness in North America. To address the lack of a genetic system for these pathogens, we used random Himar1 transposon mutagenesis to generate a library of Ap mutants capable of replicating in human promyelocytes (HL-60 cells). Illumina sequencing identified 1195 non-randomly distributed insertions. As the density of mutants was non-saturating, genes without insertions were either essential for Ap, or spared randomly. To resolve this question, we applied a biostatistical method for prediction of essential genes. Since the chances that a transposon was inserted into genomic TA dinucleotide sites should be the same for all loci, we used a Markov chain Monte Carlo model to estimate the probability that a non-mutated gene was essential for Ap. Predicted essential genes included those coding for structural ribosomal proteins, enzymes involved in metabolism, components of the type IV secretion system, antioxidant defense molecules and hypothetical proteins. We have used an in silico post-genomic approach to predict genes with high probability of being essential for replication of Ap in HL-60 cells. These results will help target genes to investigate their role in the pathogenesis of human anaplasmosis.

Unstressed antepartum cardiotocography in the management of the fetus suspected of growth retardation.

A detailed analysis of the antenatal cardiotocographs (CTGs) in 57 patients with suspected fetal growth retardation is presented. Four traces were normal and 53 were 'non-reactive. 'Non-reactive' traces can be sub-divided into three categories, which, in order of severity are, 'suspect', 'flat' and 'ominous'. When compared with the 'suspect' group, perinatal mortality was significantly increased and the Apgar scores at one and five minutes significantly decreased in the 'flat' and 'ominous' groups. The presence of fetal distress in labour was significantly higher in the 'flat' group as compared with the 'suspect' group. Intrauterine deaths occurred only in the 'ominous' group. With experience, ten patients later in the series with 'ominous' patterns were delivered within 24 hours of the detection of such and nine infants survived. At follow-up between 6 and 34 months after birth, psychomotor development was normal in 47 of the 49 surviving infants.

Pharmacokinetics of an orally administered methylcellulose formulation of gallium maltolate in neonatal foals.

Gallium is a trivalent semi-metal with anti-microbial effects because of its incorporation into crucial iron-dependent reproductive enzyme systems. Gallium maltolate (GaM) provides significant gallium bioavailability to people and mice following oral administration and to neonatal foals following intragastric administration. To study the prophylactic and therapeutic effects of GaM against Rhodococcus equi pneumonia in foals, we developed a methylcellulose formulation of GaM (GaM-MCF) for oral administration to neonatal foals. Normal neonatal foals were studied. Six foals received 20 mg/kg and another six foals received 40 mg/kg of GaM-MCF orally. Serial serum samples were collected and serum gallium concentrations were determined using inductively coupled plasma mass spectroscopy. Gallium was rapidly absorbed (T(max) of 4 h), and a mean C(max) of 0.90 or 1.8 microg/mL was achieved in foals receiving 20 or 40 mg/kg respectively. Marked variability existed in C(max) among foals: only half of the foals receiving 20 mg/kg attained serum concentrations of >0.7 microg/mL, a level suggested to be therapeutic against R. equi by previous studies. Mean elimination half-life was 32.8 or 32.4 h for foals receiving 20 or 40 mg/kg respectively. The results of this study suggest that at least 30 mg/kg orally every 24 h should be considered in future pharmacodynamic and efficacy studies.

Smoking in pregnancy: effects on mother and fetus.

The maternal and fetal effects of smoking tobacco or non-tobacco cigarettes were studied in 75 pregnant patients and compared with a matched control group of 22 pregnant patients who did not smoke. The increase in maternal heart rate, maternal mean arterial pressure and fetal heart rate, and decrease in fetal heart rate 'baseline variability' and in fetal movements, were shown to be due primarily to the nicotine content of the cigarette.

PIP: The maternal and fetal effects of smoking tobacco or nontobacco cigarettes were studied in 75 pregnant patients and compared with a matched control group of 22 pregnant patients who did not smoke. The 75 smokers included were aged 19-44, between 35-39 weeks gestation, and smoked an average of 21 cigarettes/daily; all of them inhaled. There were no stillbirths and no neonatal deaths of the 27 babies with clinically suspected intrauterine growth retardation, but 17 were found to be below the 10th centile of weight for gestation at birth. The 50 patients who smoked a nontobacco cigarette followed by a tobacco cigarette showed no significant differences in the maternal heart rate, maternal mean arterial pressure, fetal heart rate, fetal heart rate baseline variability, before and after smoking the nontobacco cigarette, but there was a significant increase in maternal heart rate, maternal mean arterial pressure, and fetal heart rate and a significant decrease in fetal heart rate baseline variability after smoking the tobacco cigarette. The frequency of fetal movements was greatest when the subject did not smoke, intermediate when she smoked 2 nontobacco cigarettes, and least when she smoked 2 tobacco cigarettes. This study suggests that the main effects of cigarette smoking on the fetal and maternal heart rate and arterial pressure is due to the nicotine content of the cigarette. The authors suggest that allowing the mother to hear the changes in her baby's heart after smoking may have a strong motivating influence on her to reduce her cigarette consumption.

A randomized controlled trial of non-stress antepartum cardiotocography.

In a prospective randomized controlled study of non-stress antepartum cardiotocography (CTG), involving 569 tracings in 300 patients, "non-reactive' traces showed a significant association with still-births and neonatal deaths, intrauterine growth retardation, admission to special care baby unit for conditions associated with intrauterine hypoxia, and low Apgar scores at 1 and 5 min. The report of the CTG was made available to the clinician in 144 patients and withheld in 156 patients. With the report available, significantly more patients were allowed to continue their antenatal care as out-patients, and significantly more antenatal in-patients were allowed home. There were no other significant differences in management, or outcome in the two groups.

Antepartum fetal heart rate monitoring in multiple pregnancy.

The assessment of fetal wellbeing in patients with multiple pregnancy by nonstressed antepartum cardiotocography is technically feasible and of clinical value. In 50 patients (101 babies) who were monitored during the antepartum period, there were five patients in whom one of a pair of twins showed a non-reactive cardiotogram. Four of these babies died (two intrauterine deaths and two neonatal deaths). All of these five babies were growth retarded at birth. The cardiotocograms from the other 96 fetuses were 'reactive' and these babies were normal. Cardiotocography seems to be a better predictor of perinatal mortality and morbidity than serial urinary oestrogens or serial biparietal diameter measurements in multiple pregnancy.

Unstressed antepartum cardiotocography in the management of the fetus suspected of growth retardation.

A detailed analysis of the antenatal cardiotocographs (CTGs) in 57 patients with suspected fetal growth retardation is presented. Four traces were normal and 53 were 'non-reactive'. 'Non-reactive' traces can be sub-divided into three categories, which, in order of severity are, 'suspect', 'flat' and 'ominous'. When compared with the 'suspect' group, perinatal mortality was significantly increased and the Apgar scores at one and five minutes significantly decreased in the 'flat' and 'ominous' groups. The presence of fetal distress in labour was significantly higher in the 'flat' group as compared with the 'suspect' group. Intrauterine deaths occurred only in the 'ominous' group. With experience, ten patients later in the series with 'ominous' patterns were delivered within 24 hours of the detection of such and nine infants survived. At follow-up between 6 and 34 months after birth, psychomotor development was normal in 47 of the 49 surviving infants.