Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

The effects of modern cementing techniques on the longevity of total hip arthroplasty

Modern prosthetic design and cementing techniques have dramatically improved femoral component fixation. Compared to studies reported in the 1970s, the incidence of radiographic loosening for periods up to 5 years postoperatively has been reduced by at least a factor of 10. These results are the benchmark by which alternative forms of femoral component fixation must be measured. With the likelihood of increased longevity of total hip arthroplasty resulting from improved fixation, the problems of wear debris from the bearing surfaces and loss of bone stock with time will become preeminent.     

Ultrasonic measurement of immobilization-induced osteopenia: An experimental study in sheep

Summary An animal model was used to examine the use of noninvasive transmission ultrasound to measure changes in bone mass which occur following disuse. Unilateral achilles tenectomy was performed on the left leg of eight adult sheep. Following a 12-week period of nonweight bearing, presacrifice transmission ultrasound measurements were taken across the calcanei of the intact and the experimental limbs and compared with those values taken postoperatively. Following specimen harvest, cross-sectional areas of the bones were quantified by microradiography and stereology, and compared with thein vivo ultrasound measurements. There was an average of 8.6% less total bone area, and 18.0% less trabecular volume fraction in the experimental nonweight-bearing limbs as compared with control intact calcanei. The difference in bone mass was associated with a 9.0% decrease in the velocity of sound from the postoperative to the presacrifice ultrasound measurements taken from the experimental calcanei, and a 2.3% increase in the control calcanei. The velocity of sound was found by the Student'st test to be a highly reliable discriminator between the experimental and control limbs.     

Determinants of acquisition of MR imaging units in an era of prospective payment

A survey was undertaken to examine the impact of Medicare's Prospective Payment System (PPS) and other recent changes in the health care environment on providers' decisions regarding acquisition of high-cost technologic equipment. The survey group included 199 hospitals and freestanding imaging centers known to have acquired magnetic resonance (MR) imaging units, as well as a random sample of 400 hospitals whose acquisition decisions were unknown to the authors. Fifty-eight percent of the known adopters and 61% of the randomly selected hospitals responded to the survey. Nonadopters' decisions were dominated by economic considerations, including the high cost of MR imagers and concerns about Medicare's reimbursement policies. Competition and a desire to provide the highest quality of care are counterbalancing the retardant effects of PPS, however, and are stimulating widespread diffusion of MR imagers.     

Virulence profiling and quantification of verocytotoxin-producing Escherichia coli O145:H28 and O26:H11 isolated during an ice cream-related hemolytic uremic syndrome outbreak

In September-October 2007, a mixed-serotype outbreak of verocytotoxin-producing Escherichia coli (VTEC) O145:H28 and O26:H11 occurred in the province of Antwerp, Belgium. Five girls aged between 2 and 11 years developed hemolytic uremic syndrome, and seven other coexposed persons with bloody diarrhea were identified. Laboratory confirmation of O145:H28 infection was obtained for three hemolytic uremic syndrome patients, one of whom was coinfected with O26:H11. The epidemiological and laboratory investigations revealed ice cream as the most likely source of the outbreak. The ice cream was produced at a local dairy farm using pasteurized milk. VTEC of both serotypes with indistinguishable pulsed-field gel electrophoresis patterns were isolated from patients, ice cream, and environmental samples. Quantitative analysis of the ice cream indicated concentrations of 2.4 and 0.03 CFU/g for VTEC O145 and O26, respectively. Virulence typing revealed that the repertoire of virulence genes carried by the O145:H28 outbreak strain was comparable to that of O157 VTEC and more exhaustive as compared to the O26:H11 outbreak strain and nonrelated clinical strains belonging to these serotypes. Taken together, these data suggest that O145:H28 played the most important role in this outbreak.