Biology and behaviour of the cercariae of a Sanguinicola sp. in the river Cilloruelo (Salamanca, Spain)

In the light of the hydrodynamic characteristics of the river Cilloruelo (province of Salamanca, Spain) and the results on the shedding of lophocercariae of a Sanguinicola sp. by naturally infected Ancylus fluviatilis, a discussion is made of the influence of different temperatures on shedding and survival of the cercariae. Comments are also made concerning the most likely periods and zones of the river for infection of the definitive host.     

Messenger RNAs for trk and the low-affinity NGF receptor in rat basal forebrain.

Nerve growth factor (NGF) acts by binding to specific sets of neurons. Low-affinity binding (Kd of 10(-9) M) is mediated via a 75 kDa glycoprotein (LNGFR). Recently, a 140 kDa tyrosine protein kinase encoded by the proto-oncogene trk has been found to bind NGF with high affinity (Kd of 10(-11) M) and to evoke neurotrophic responses. In addition, the related trkB protein and the LNGFR have been shown to bind brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) with an affinity of Kd 10(-9) M. We demonstrate the distribution of mRNA encoding the neurotrophin-binding proteins in the forebrain of the 21-day-old Sprague-Dawley rat by in-situ hybridization. Expression of trk and LNGFR mRNA showed co-localization and was restricted to the medial septal nucleus and the nucleus of Broca's diagonal band, suggesting a receptor function in these cells for both proteins encoded. In contrast, expression of trkB was widely spread in many areas. Thus trkB protein might serve general functions in the forebrain.     

Reduced haemoglobin levels in infants presenting with apparent life-threatening events–a retrospective investigation

Anaemia has been shown to be associated with an increased apnoeic pause frequency and with cyanotic breath-holding spells. In this study, the relationship between anaemia and apparent life-threatening events was retrospectively investigated in 72 term infants referred for assessment and home monitoring following an apparent life-threatening event. For 41 infants (25 male, 16 female; 38 Caucasian, three Asian) a venous red blood cell count was available. Their median age at the time of the apparent life-threatening event was 2.0 (0.6-6.7) months. The Hb levels in these 41 infants were plotted against normal data from the literature. Thirty-four infants had Hb levels below the mean, whilst six infants had values above the corresponding normal mean; the one remaining infant had a Hb value identical to the normal mean. Significantly more infants than expected had Hb levels below the mean (p less than 0.001, binomial test). Anaemia may have played a role in the pathophysiology leading to life-threatening events in some of the infants investigated in this study.     

False-positive human immunodeficiency virus type 1 western blot tests in noninfected blood donors

Background: The manufacturers' criteria for a positive human immunodeficiency virus type 1 (HIV-1) Western blot (WB) test were recently revised to require reactivity to only two of the following bands: p24, gp41, and gp120/160. In a recent report, low-risk blood donors were identified in whom nonspecific reactivity to multiple env antigens in WB testing resulted in apparently false-positive WBs by these criteria. The present study was conducted to verify the existence of false-positive WBs among noninfected donors and to assess the extent of this problem. Study Design and Methods: Four donors classified as WB- positive on the basis of env-only (3 cases) or p24/env-only (1 case) patterns were investigated. Index and/or follow-up specimens were tested by polymerase chain reaction (PCR), by overlapping recombinant env antigens and synthetic peptides in enzyme immunoassays, and by deglycosylated and denatured antigen WBs. WB records from American Red Cross blood centers were reviewed to determine the frequency of env- only and p24/env-only patterns, relative to all positive WBs, from 1988 through 1993. Results: The four index-case donors denied risk and had stable WB reactivity during follow-up. HIV PCR was negative in all. Env reactivity was restricted to nonglycosylated gp41 epitopes; no gp120- specific reactivity was detected. For three of the four donors, env reactivity was mapped to a 20-amino acid N-terminal epitope of gp41. The rate of detecting WBs with these false-positive patterns increased from 0.6 percent of all positive WBs from 1988 to 1990 (4/776) to 8 percent in 1991 and 1992 (52/683), and then it declined to 6 percent in 1992 and 1993 (47/783). Env-only patterns predominated in 1991 and 1992, whereas p24/env-only patterns were more frequent following implementation of combined anti-HIV-1/HIV type 2 enzyme immunoassays in 1992. Conclusion: Low-risk blood donors can have false-positive results on WB tests. Increased detection of env-only and p24/env-only WBs appears related to the enhanced sensitivity of newer enzyme immunoassays to gp41 and p24 antibodies. Donors with these patterns should undergo follow-up testing to document the presence or absence of HIV infection.     

DMFT and treatment needs in adult population of Oviedo, Spain

Abstact An epidemiological survey was carried out in 1992 researching dental caries and treatment needs in an adult population in Oviedo, Spain. A representative sample of 261 subjects, randomly obtained and stratified by age, was examined. Results show a dental decay prevalence of 99.6%; 12.5 DMFT index with 2.9. 7.5 and 2.1 mean values for D, M and F components. Women and the lower social class showed the highest DMFT index. Treatment needs reach a mean value of 12.1 teeth per person. Politics are the most needed treatment, the mean value increases with age while the differences among age groups and social classes are statistically significant. The next most needed dental treatment is filling of one surface which decreases with age, is the same for men and women and higher among the middle social class; the differences arc statistically significant among the social classes.