Frequency of holoprosencephaly in the International Clearinghouse Birth Defects Surveillance Systems: searching for population variations

BACKGROUND: Holoprosencephaly (HPE) is a developmental field defect of the brain that results in incomplete separation of the cerebral hemispheres that includes less severe phenotypes, such as arhinencephaly and single median maxillary central incisor. Information on the epidemiology of HPE is limited, both because few population‐based studies have been reported, and because small studies must observe a greater number of years in order to accumulate sufficient numbers of births for a reliable estimate. METHODS: We collected data from 2000 through 2004 from 24 of the 46 Birth Defects Registry Members of the International Clearinghouse for Birth Defects Surveillance and Research. This study is based on more than 7 million births in various areas from North and South America, Europe, and Australia. RESULTS: A total of 963 HPE cases were registered, yielding an overall prevalence of 1.31 per 10,000 births. Because the estimate was heterogeneous, possible causes of variations among populations were analyzed: random variation, under‐reporting and over‐reporting bias, variation in proportion of termination of pregnancies among all registered cases and real differences among populations. CONCLUSIONS: The data do not suggest large differences in total prevalence of HPE among the studied populations that would be useful to generate etiological hypotheses. Birth Defects Research (Part A), 2008. © 2008 Wiley‐Liss, Inc.     

First visceral leishmaniasis focus in Argentina

An eight-year old boy from Posadas (27 masculine 23'S, 55 masculine 54'W) was diagnosed with visceral leishmaniasis (VL) during 2006. Lutzomyia longipalpis was discovered in the backyard of his house, while the spread of canine visceral leishmaniasis was confirmed in Posadas. This is the southernmost report of a VL transmission focus and the first in Argentina.     

Growth of dimorphic human pathogenicfungi on media containing cycloheximide and chloramphenicol

Summary Studies of 24 strains ofBlastomyces dermatitidis confirmed previously published results that the yeast-phase of this fungus is more sensitive than the mycelial-phase to cycloheximide and chloramphenicol.Studies of 5 strains each ofHistoplasma capsulatum, Paracoccidioides brasiliensis andSporotrichum schenckii show that that these species also have a similar yeast-phase mycelial -phase sensitivity differential in regard to these antibiotics.A cycloheximide resistant strain ofB. dermatitidis was developed from a sensitive strain.The experimental results support the general practice of using 0.5 mg/ml cycloheximide and 0.05 mg/ml chloramphenicol in media for the isolation of the four fungi at 25° C. The results indicate, however, that some strains would not be recovered at 37° C with similar concentrations of these antibiotics.It is recommended that a concentration of not more than 0.2 mg/ml chloramphenicol should be used to preserve sputum which is subsequently to be cultured forB. dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis orS. schenckii.     

Nitrate Supply and the Biophysics of Leaf Growth in Salix viminalis

The influence of nitrogen on leaf area development and the biophysicsof leaf growth was studied using clonal plants of the shrubwillow, Salix viminalis grown with either optimal (High N) orsub-optimal (Low N) supplies of nitrate. Leaf growth rate andfinal leaf size were reduced in the sub-optimal treatment andthe data suggest that in young rapidly growing leaves, thiswas primarily due to changes in cell wall properties, sincecell wall extensibility (% plasticity) was reduced in the LowN plants. The biophysical regulation of leaf cell expansion also differedwith nitrogen treatment as leaves aged. In the High N leaves,leaf cell turgor pressure (P) increased with age whilst in theLow N leaves P declined with age, again suggesting that foryoung leaves, cell wall plasticity limited expansion in theLow N plants. Measurements of cell wall properties showed thatcell wall elasticity (%E) was not influenced by nitrogen treatmentand remained constant regardless of leaf age. Key words: Salix, cell wall extensibility, nitrogen nutrition, biophysics of leaf growth     

Exposure to diethylstilbestrol during pregnancy permanently alters the ovary and oviduct

To determine the effects of transplacental exposure to diethylstilbestrol (DES) on the ovary and oviduct of the CD-1 mouse, timed pregnant mice were injected subcutaneously with DES (100 micrograms/kg) on Days 9 through 16 of gestation and female offspring sacrificed from 4 weeks to 10 months of age. Following DES exposure, ovarian alterations such as inflammation, a prominent interstitial compartment composed of medullary tubule-like structures, and intra- and para-ovarian cysts from mesonephric remnants were observed. In addition, there were oviductal abnormalities including malformation. As reported previously, the oviduct was closely adherent and coiled around the ovary in a similar position to that seen in the fetal mouse. This malformation was termed developmental arrest of the oviduct (DAO) and was a consistent finding in female offspring exposed prenatally to DES (100 micrograms/kg). Increased prevalence of salpingitis and microscopic alterations in the oviduct were also observed. Oviductal epithelium was mostly secretory type with basal vacuoles. In some cases, oviductal epithelium was hyperplastic and formed mucosal folds resembling glands which extended through the muscularis (diverticulosis). The extent of the adenomatous mucosal folds and the degree of extension through the muscularis increased with the age of the animal (100% at 10 months). Some characteristics of this abnormality resembled salpingitis isthmica nodosa, a lesion described in women which is associated with ectopic pregnancies and subfertility. Gross and microscopic changes in the oviduct were more consistent than were the changes among other portions of the reproductive tract of DES-treated mice previously reported. Since subfertility has been described in this mouse model as well as in prenatally DES-exposed women, the data presented in this report may help in evaluation of the reported reduced fertility in exposed patients as well as other infertility patients.