A new member of the Anopheles quadrimaculatus complex, species C

A new member, species C, of the Anopheles quadrimaculatus complex was recently found in collections from the northwest coast of Florida. This new species cannot be differentiated from the other 2 species with available taxonomic keys. Evidence for this taxon as a sibling species includes data on hybrid sterility and distorted sex ratios in the progeny of crosses to species A and B, chromosomal differences, and diagnostic allozymes.     

Adenosine and its analogs stimulate phosphoinositide hydrolysis in the kidney

Renal blood flow, glomerular filtration rate and sodium excretion are known to be affected by adenosine. The present studies were undertaken to investigate the actions of adenosine and its analogs (both agonists and antagonists) on phosphoinositide (PI) hydrolysis in the outer medullary slices. Adenosine was found to cause a dose-dependent stimulation of PI hydrolysis (ED50, 2.8 microM) in renal slices from outer medulla. The adenosine analogs 5'-(N-cyclopropyl)-carboxamidoadenosine (NCCA) and 5'-N-ethylcarboxamidoadenosine (NECA) also stimulated PI hydrolysis in renal medulla. Stimulation of PI hydrolysis was blocked by the adenosine antagonists: aminophylline, 1,3-dipropyl-7-methylxanthine (DMX) and 8-(p-sulfophenyl)-theophylline (8-SPT). Caffeine not only antagonized adenosine-stimulated PI hydrolysis but also increased PI hydrolysis independently. These results indicate that adenosine stimulates PI hydrolysis in renal medulla through a receptor-mediated mechanism.     

Comparative susceptibility of species A, B and C of Anopheles quadrimaculatus complex to infection with subperiodic Brugia malayi and Brugia pahangi (Nematoda: Filarioidea).

Susceptibilities of natural populations of sibling species A, B and C of the Anopheles quadrimaculatus complex and the colonized strain A to subperiodic Brugia malayi and Brugia pahangi were compared. All 3 sibling species showed varying degrees of susceptibility to both B. pahangi and B. malayi, and they were considerably more susceptible to B. pahangi than to B. malayi. The rate and intensity of infection to B. pahangi were highest for species A (66.2% and 7.4 L3/female, respectively) and lowest for species B (21.3% and 1.7 L3/female). For B. malayi these values were higher for species A (29.7% and 1.84 L3/female) than for species B (13.3% and 0.86 L3/female) and C (12.6% and 0.75 L3/female). The colonized strain A of An. quadrimaculatus was significantly more susceptible to both Brugia species than the natural populations of sibling species A, B and C.     

Outbreak of Pichia anomala infection in the pediatric service of a tertiary-care center in Northern India

An outbreak of nosocomial fungemia due to the unusual yeast, Pichia anomala occurred in the pediatric wards of our hospital over a period of 23 months (April 1996 to February 1998). A total of 379 neonates and children (4.2% admissions) were infected. The probable index case was admitted to the pediatric emergency ward, with subsequent transmission to the premature nursery, pediatric intensive care units, and other children wards. Carriage on the hands of health care personnel was likely to be responsible for dissemination of the fungus. The outbreak could only be controlled after a health education campaign to improve hand-washing practices was instituted and after nystatin-fluconazole prophylaxis to all premature neonates and high-risk infants was introduced. In a case-control study, we identified a lower gestational age, a very low birth weight (<1,500 g), and a longer duration of hospital stay as significant risk factors associated with P. anomala fungemia in premature neonates. We conducted a culture prevalence survey of 50 consecutive premature neonates and found that 28% were colonized with P. anomala at a skin or mucosal site on the date of delivery and that 20% of these neonates subsequently developed P. anomala fungemia. We performed multilocus enzyme electrophoresis on 40 P. anomala outbreak isolates (including patient and health care workers' hand isolates), and the results suggested that these isolates were identical. Our study highlights the importance of P. anomala as an emerging nosocomial fungal pathogen.