Streptococcus pneumoniae serogroup 6 clones over two decades.

The major evolutionary stresses on Streptococcus pneumoniae are thought to be the widespread use of antibiotics and the deployment of effective vaccines against the capsular polysaccharides. Our current knowledge of genetic lineages among pneumococcal isolates comes largely from investigations just before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) introduced in 2000. We examined 66 serogroup 6 isolates from the 1970s, long before the introduction of PCV7 and before widespread penicillin resistance was common in Birmingham, Alabama, to look for ancestors of the clones that came into play around the introduction of the PCV7 vaccine. The hypothesis was that some clonal complexes, if not individual clones, would be stable enough to persist over this period of time. We compared the 1970s isolates with 122 isolates from the 1990s in US and worldwide collections. Genotyping with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) revealed that while some clones were probably localized to our area, others have persisted within groups that have expanded or diminished over the years.

The influence of insulin administration after weaning the first litter on ovulation rate and embryo survival in sows.

Primiparous crossbred sows (n = 43), lactating for an average of 21.1 +/- 0.1 d and weaning 8.7 +/- 0.1 pigs, were used to evaluate the influence of insulin on ovulation rate and embryo survival. The sows were maintained on 2.3 kg/head/d of a 14% protein gestation diet during pregnancy, fed ad libitum during lactation, given 2.7 kg/head/d from weaning until re-breeding and fed 2.3 kg/head/d after mating. Beginning the day after weaning (Day 0) sows were treated with 0.4 IU/kg body weight (BW) insulin (n = 21) or were administered an equivalent volume of saline (n = 22) for 4 d. Beginning on Day 3 and continuing until Day 14 after weaning, the sows were checked for estrus twice daily and were artificially inseminated using pooled semen from 2 fertile boars. At slaughter (days 30 to 40 of gestation), ovaries and uteri were collected, and the ovulation rate, embryo number and viability, and uterine weight and length were evaluated and recorded. Use of insulin decreased the average interval from weaning to estrus compared with saline by increasing percentage in estrus by Day 14 after weaning (5.0 +/- 0.57 vs 6.9 +/- 0.56 d, respectively; P < 0.03). Ovulation rate, number of embryos, embryo survival, and average uterine length and weight were not influenced by insulin treatment. Overall, insulin affected reproductive efficiency in primiparous sows by increasing the percentage of sows in estrus.

PspA family typing and PCR-based DNA fingerprinting with BOX A1R primer of pneumococci from the blood of patients in the USA with and without sickle cell disease.

Disease and mortality rates for Streptococcus pneumoniae infections are much higher in patients with sickle cell disease (SCD) than in age-matched patients without SCD. Pneumococcal surface protein A (PspA) has been proposed as a component in human vaccines against S. pneumoniae to provide greater breadth of coverage than can be obtained with the 7-valent conjugate vaccine. The cross-reactivity of PspA is associated with the 'PspA family' structure. In this study we examined strains of S. pneumoniae from patients with and without SCD to determine whether the strains infecting the hypersusceptible population of SCD patients were limited to the same two PspA families already known to comprise over 95% of strains infecting non-SCD patients. Each strain was also evaluated according to the presence or absence of specific PCR fragments based on repetitive BOX elements to screen for possible SCD-associated clonal structure. Strains from SCD and non-SCD patients were similarly dispersed among the most common BOX PCR groups and strains from both groups expressed a similar distribution of PspA variants. Thus, a PspA vaccine designed for the population at large should also be appropriate for patients with SCD.

An electrocardiographic study of cardiovascular problems in mirex-fed rat fetuses.

Sperm-positive female rats were intubated with pesticide, Mirex, in oil (5 to 10 mg/kg) on days 8 1/2 to 15 1/2. Controls were untreated or oil-fed. Testing was done on day 18 1/2. Fetuses were sequentially exposed and ECGs obtained with the fetus attached to the placenta and uterus. Counterparts of standard leads, I, II and III were used. Fetuses were weighed and examined afterwards. Swollen fetuses were rated on a scale of 1 (slight edema under chin) to 5 (3 mm edema across back). ECGs from 81 controls and 205 Mirex fetuses were obtained. They were evaluated for rate of heart beat, regularity of beat, PR intervals, and other features. One control exhibited an abnormality, a transitory period of premature atrial contractions. Mirex-fed fetuses frequently exhibited tachycardia, closely correlated with degree of edema. The heart rate increased from 150/minute in controls to 180 in slightly swollen to 224 in swollen fetuses. Mean PR intervals increased with degree of swelling and with dose. The frequency of first degree heart-block was also dose-related, ranging from 20% in the 5 mg/kg group to 77% in the 10 mg/kg group. Second-degree heart-blocks were found in 8%, 3% showed arrhythmias, and one had atrial flutter/fibrillation. These cardiovascular problems seem primarily related to the Mirex-induced edema and demonstrate that fetal edema is not innocuous. These data demonstrate the usefulness of fetal electrocardiography to detect functional teratology.

The causes of perinatal death induced by prenatal exposure of rats to the pesticide, mirex. Part I: Pre-parturition observations of the cardiovascular system.

Prenatal exposure to mirex, a chlorinated hydrocarbon insecticide, induces a high rate of perinatal death, but only a low incidence of visible abnormalities which could help to account for these deaths. This study is an attempt to determine the cause of these deaths. Pregnant rats were intubated with a moderate dose of mirex, in oil, 6 mg/kg/day, on days 8 1/2-15 1/2 of gestation. Observations, on 78 control and 136 treated fetuses, were made on the morning before parturition was expected. Fetuses were sequentially exposed and electrocardiograms obtained with the fetus attached to the placenta and uterus. ECGs were evaluated for rate of beat, regularity of beat, PR intervals, and other features. Fetuses were examined for edema level and vitality. None of the controls were dead and none had abnormal ECGs. Of the treated group, 14% were dead, 16% had a first-degree heart block, and 2% had a second-degree heart block. Some (6%) had slow, feeble atrial beats only, possibly a third-degree block, and appeared to be dying. The severity of the symptoms was proportional to the degree of visible edema. Most of the fetuses with little or no visible edema had normal ECGs, but the majority of the moderate to severely edematous fetuses (i.e., with a layer of subcutaneous edema across the back of 0.5 mm or more) had abnormal ECGs and/or were either dead or dying. These data show that the effects of mirex on the fetal cardiovascular system are a major factor in inducing prenatal death.

Position-tunable holographic filters in dichromated gelatin for use in single-mode-fiber demultiplexers.

We describe a continuously tunable reflection filter for the 1.2-1.6-microm wavelength range. The filter is a volume-reflection hologram in dichromated gelatin and exhibits high reflection efficiencies (~95%) with narrow spectral bandwidth (~l% FWHM). These filters have been initially designed for use as position-tuned wavelength demultiplexers or channel-selection switches in multichannel optical-fiber systems. A prototype device has been constructed with an insertion loss between input and output single-mode fibers of <3 dB, with bandwidths Deltalambda((1/2))(FWHM) ~1% over the wavelength band.

A Nd(3+)-doped cw fiber laser using all-fiber reflectors.

We demonstrate a novel all-fiber resonant optical cavity which uses two-fiber reflectors, each formed by a single loop of fiber between the output ports of a fiber directional coupler. The reflectivities of the fiber mirrors are each determined by the coupling ratio and the insertion loss of the fused couplers. When the cavity is formed in this way using a continuous length of Nd(3+)-doped fiber and pumped using a GaAs laser diode, lasing occurs at a wavelength of 1064 nm. Both theoretical and practical descriptions of the device are given.