Pulmonary aspiration in preschool children with cystic fibrosis

Pulmonary aspiration of gastric refluxate (PAGR) has been demonstrated in association with pulmonary inflammation in school aged children with Cystic Fibrosis (CF). We sought to determine if similar findings were present in preschool children. Pepsin was measured in Broncho-alveolar lavage (BAL) fluid collected from clinically stable preschool children with CF and controls. Elevated pepsin levels were found in a subgroup of children with CF, but this was not found to be associated with pulmonary infection, pulmonary inflammation or respiratory or gastrointestinal symptoms.     

Larval growth in the river lamprey, Lampetra fluviatilis

A series of 987 ammocoetes from the rivers Towy, Teme, and Taw have been identified as mainly L. fluviatilis (L.) on the basis of oocyte counts on female ammocoetes. The length frequency distributions for this material differs from either L. planeri or P. marinus in showing only three modes in addition to the young of the year and the length distribution of the final mode coincides with the length range for 119 metamorphosing and macrophthalmia stages of L. fluviatilis that have been found at the same sites. These animals measured from 80–117 mm in length and weights varied from 0.76–2.28 g. Metamorphosis is believed to take place in late summer and early autumn when in the majority of cases, the ammocoetes are four and a half years old. The evidence that the non-parasitic L. planeri has a longer larval life than the closely related parasitic L. fluviatilis is thought to have some significance in relation to the evolution of the brook lamprey species.     

Naked DNA vaccines expressing the prM and E genes of Russian spring summer encephalitis virus and Central European encephalitis virus protect mice from homologous and heterologous challenge.

Naked DNA vaccines expressing the prM and E genes of two tick-borne flaviviruses, Russian spring summer encephalitis (RSSE) virus and Central European encephalitis (CEE) virus were evaluated in mice. The vaccines were administered by particle bombardment of DNA-coated gold beads by Accell gene gun inoculation. Two immunizations of 0.5 to 1 microg of RSSE or CEE constructs/dose, delivered at 4-week intervals, elicited cross-reactive antibodies detectable by enzyme-linked immunosorbent assay and high-titer neutralizing antibodies to CEE virus. Cross-challenge experiments demonstrated that either vaccine induced protective immunity to homologous or heterologous RSSE or CEE virus challenge. The absence of antibody titer increases after challenge and the presence of antibodies to E and prM, but not NS1, both before and after challenge suggest that the vaccines prevented productive replication of the challenge virus. One vaccination with 0.5 microg of CEE virus DNA provided protective immunity for at least 2 months, and two vaccinations protected mice from challenge with CEE virus for at least 6 months.     

Expansion of the CGG repeat in fragile X in the FMR1 gene depends on the sex of the offspring.

Analysis of 139 mother-to-offspring transmissions of fragile X CGG triplet repeats revealed that the repeat expansion is enhanced in mother-to-son transmissions compared with mother-to-daughter transmissions. Evidence has been based on analysis of mother-offspring differences in the size of repeat (in kb), as well as on comparisons between proportions of male and female offspring with premutations, and full mutations, inherited from mothers carrying a premutation. Mean difference in the repeat size from mother-son transmissions was 1.45 kb, compared with mother-daughter transmissions of 0.76 kb. The difference is due primarily to a greater proportion of male than female offspring with full mutation from the premutation mothers and also to a higher frequency of reduction in repeat size from mothers to daughters than from mothers to sons. Our findings suggest the possibility of an interaction of the normal X homologue in a female zygote with the FMR1 sequence on the fragile X during replication to account for the lower level of expansion in mother-to-daughter transmissions relative to mother-to-son transmissions.     

Timing and genetic rapport between growth in skeletal maturity and height around puberty: similarities and differences between girls and boys.

We have analyzed longitudinal twin data by using a multivariate normal model to identify and quantify genetic effects over time on two main aspects of growth, height and skeletal maturity. The largest genetic contribution to the variance in both height and skeletal maturity coincided with the respective ages of peak growth velocity. The highest genetic covariance between these two traits coincided with the age of greatest acceleration of growth in height. These findings imply the existence of regulatory or structural genes that influence growth in both height and skeletal maturity. We also found sex differences in the rapport between velocities for height and skeletal maturity. These are consistent with a predominant role of estrogen in accelerating skeletal maturation in females, and the existence of additional mechanisms in males which may promote growth in height independently of the effects of gonadal sex steroids.     

Tritiated water as a measure of body water in immature rats growing at different rates

Rats were reared from birth in litters of 4, 10, and 16 to achieve different growth rates. Pups in the litters of 16 had no access to rat chow until days 21-28, when chow was made available to one of the litters to induce catch-up growth. Total body water was estimated by tritiated water (TBWHTO) on days 7, 14, 21, and 28 and then calculated from desiccation (TBWdes). TBWHTO was consistently larger than TBWdes for all groups. Differences were 10.9-16.9% on day 7 and 3.7-6.4% on day 28. On day 28, percent difference was higher in the slower-growing than the faster-growing groups. Nonaqueous hydrogen exchange was determined from tritium activity in the dried carcass. Less than 1% of the injected tritium exchanged with nonaqueous hydrogen during the equilibration period. Thus differences between TBWHTO and TBWdes in the younger animals could not be accounted for by nonaqueous hydrogen exchange but may have resulted from a larger loss of injected tritium, possibly in insensible water.