Chemotaxis of polymorphonuclear leukocytes from donors of different races toward Neisseria gonorrhoeae of three different auxotypes

Urethral gonorrhea is typified by the presence of large numbers of polymorphonuclear leukocytes, which are presumably attracted to the urethra by an as yet uncharacterized chemotaxin. Culture supernatants from three different auxotypes of Neisseria gonorrhoeae, one requiring arginine, hypoxanthine, and uracil (Arg-,Hyx-,Ura-), one requiring proline, arginine (not satisfied by ornithine), and uracil (Pro-,Arg-[Orn*],Ura-), and one requiring proline (Pro-), were tested for their chemotactic activity against leukocytes from men of two racial groups, white and black. These auxotypes were chosen because the Pro- auxotype is isolated more frequently from black patients, and the Arg-,Hyx-,Ura- and the Pro-,Arg-(Orn*),Ura- auxotypes are isolated more frequently from white patients. Chemotaxis was tested in blind-well chambers in the absence of complement; membranes with a pore size of 3 microns were used. The culture supernatants of the Pro- auxotype were the most chemotactic, while those of the Arg-,Hyx-,Ura- were the least chemotactic when analyzed by a three-way analysis of variance: F = 22.83, df = 2.6, P less than .001. There were no differences in migration with respect to the race of the donor. Gonococcal culture supernatants did not require complement for chemotaxis.     

Bronchoscopy findings in children and young adults with tracheostomy due to congenital anomalies and neurological impairment

The aim of this study was to examine bronchoscopy findings for children and young adults with long-term tracheostomies due to congenital anomalies and neurological impairment and identify characteristics associated with abnormal bronchoscopic findings. We conducted a retrospective study of 128 bronchoscopy cases (81 children) at a pediatric rehabilitation center. Thirty-eight cases (30%) had normal findings and 14 children (17% of all children) were decannulated following bronchoscopy. Ninety cases (70% of cases) had abnormal findings (e.g. granulomas, airway inflammation, fixed obstruction). An acute indication for bronchoscopy was the strongest predictor of an abnormal finding, while age (younger) and diagnosis (multiple congenital anomalies (MCA)) also were associated with abnormalities. For a subsample of children undergoing bronchoscopy for routine surveillance (n= 90), underlying diagnosis (MCA) was the strongest predictor of an abnormal finding, while younger age contributed slightly. These findings add to the limited literature describing bronchoscopic findings in children and youth with tracheostomies due to congenital anomalies or neurological impairment. These findings may be useful for rehabilitation clinicians in determining care needs for children with long-term tracheostomy.     

Geochemical proxies of North American freshwater routing during the Younger Dryas cold event

The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from approximately 12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (DeltaMg/Ca, U/Ca, and (87)Sr/(86)Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic delta(18)O(seawater) and delta(13)C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 +/- 0.02 Sverdrup (1 Sverdrup = 10(6) m(3).s(-1)). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of approximately 0.06-0.12 Sverdrup, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.     

In vitro high-resolution structural dynamics of single germinating bacterial spores

Although significant progress has been achieved in understanding the genetic and biochemical bases of the spore germination process, the structural basis for breaking the dormant spore state remains poorly understood. We have used atomic force microscopy (AFM) to probe the high-resolution structural dynamics of single Bacillus atrophaeus spores germinating under native conditions. Here, we show that AFM can reveal previously unrecognized germination-induced alterations in spore coat architecture and topology as well as the disassembly of outer spore coat rodlet structures. These results and previous studies in other microorganisms suggest that the spore coat rodlets are structurally similar to amyloid fibrils. AFM analysis of the nascent surface of the emerging germ cell revealed a porous network of peptidoglycan fibers. The results are consistent with a honeycomb model structure for synthetic peptidoglycan oligomers determined by NMR. AFM is a promising experimental tool for investigating the morphogenesis of spore germination and cell wall peptidoglycan structure.     

Polyorchidism in a child with imperforate anus

Polyorchidism is a rare diagnosis. When recovered, it is frequently found in combination with other urologic pathologies. We report the case of a 14-month-old child with imperforate anus who was found to have polyorchia during repair of his inguinal hernia. Although cryptorchidism is not an uncommon finding in patients with imperforate anus, polyorchidism has never been reported. This is an unusual presentation of a rare entity.