Comparison of the cost and effectiveness of two strategies for maintaining hepatitis B immunity in hemodialysis patients

A decision-analysis model was developed to compare the strategies to maintain hepatitis B virus (HBV) immunity in hemodialysis patients who responded to the primary HBV vaccine. Our hypothesis is that the routine, annual administration of the vaccine booster to all hemodialysis patients (non-screening strategy) is more cost-effective than the current strategy of vaccination based on anti-HBs titers (screening strategy). Under baseline assumptions, the screening strategy was less costly and was associated with fewer HBV infections than the non-screening strategy. The results of our model did not support our hypothesis, and indicate that regularly screening patients for HBV immunity before revaccination is less costly and more effective than the empiric vaccination of hemodialysis patients.     

Adult cranial dura I: intrinsic vessels

This is the first of two articles designed to provide user-friendly schematics of the adult dural vascular anatomy. It describes the intrinsic meningeal arteries and veins of the skull base/cranial vault and the dural partitions (the tentorium, falx cerebelli, and falx cerebri). The discussion of this anatomy is supplemented by illustrative pathologic insights. The second article focuses on the dural sinuses and their remaining tributaries from the brain, diplo?, and emissary veins from the extracranial soft tissues. This information will assist in interpreting neuroimaging studies, communications with clinicians, and teaching of this difficult subject.     

Low-dose cholinesterase inhibitors do not induce delayed effects on cerebral blood flow and metabolism

The acetylcholinesterase (AChE) inhibitors sarin and pyridostigmine bromide (PB) have been proposed as causes of neurobehavioral dysfunction in Persian Gulf War veterans. To test possible delayed effects of these agents, we exposed rats to low (subsymptomatic) levels of sarin (0.5 LD₅₀ s.c. 3 times weekly) and/or PB (80 mg/L in drinking water) for 3 weeks. Controls received saline s.c. and tap water. At 2, 4 and 16 weeks after exposure, regional cerebral blood flow (rCBF) and glucose utilization (rCGU) were measured in conscious animals with the Iodo-¹⁴C-antipyrine and ¹⁴C-2 deoxyglucose methods, respectively.

Two weeks after exposure, PB+sarin caused significant rCBF elevations, but no changes in rCGU, in neocortex, with lesser effects on allocortex. Four weeks after exposure, the same general pattern was found with sarin. Only a few changes were found at 16 weeks post-treatment. The predominant effects of sarin or PB+sarin on rCBF at earlier times after treatment are consistent with the well known direct cerebral vascular effect of cholinergic agonists. The lack of changes in rCBF and rCGU observed at 16 weeks after treatment does not support the hypothesis that repeat exposure to low-dose cholinesterase inhibitors can generate permanent alterations in cerebral activity.     

Some aspects of the bonds interlinking soluble fibrin complexes in human plasma

I¹²⁵ labelled fibrinogen was used to study the appearance of soluble fibrin complexes in thrombin incubated citrated plasma or in glass activated native plasma. Polyacrylamide gel (4%) electrophoresis demonstrated that approximately 7% of the plasma fibrinogen had been converted to slower moving species, eg. soluble fibrin complexes. Only a minor part of these complexes, with mobility as a fibrinogen derived dimer, persisted upon electrophoresis in the presence of 5 M urea. Also, agarose gel chromatography (Seph. 4 B) revealed the formation of high molecular weight fibrin/fibrinogen derivatives, which disappeared when chromatography was performed in the presence of 5 M urea.Thus, the major part of the soluble fibrin complexes in plasma was not resistant to urea, indicating that mainly non covalent bonds were involved. This implicates only a minor part of such complexes in a plasma milieu to be cross-linked through the action of the Fibrin Stabilizing Factor.     

Intraurethral knot in a very-low-birth-weight infant: radiological recognition, surgical management and prevention

We report a case where a knot developed in a urinary catheter and became lodged within the urethra of a very-low-birth-weight (VLBW) preterm infant. The catheter was removed with the assistance of a urologist. We recommend using caution when placing urinary catheters in VLBW infants and question the appropriateness of feeding tubes as catheters. Recognition on radiographs of malpositioned bladder catheters is vital to the care of these patients. All staff involved in the insertion, maintenance or removal of these catheters should be suitably trained to minimize the risk of knots and related complications.     

Adequacy of androgen replacement influences bone density response to testosterone in androgen-deficient men

OBJECTIVE: Androgen deficiency (AD) leads to bone loss and contributes to osteoporotic fractures in men. Although low bone mineral density (BMD) in AD men is improved by testosterone replacement, the responses vary between individuals but the determinants of this variability are not well defined. DESIGN AND METHODS: Retrospective review of dual energy X-ray absorptiometry (DEXA) of the lumbar spine and proximal femur in men with established AD requiring regular androgen replacement therapy (ART). After a DEXA scan all men were treated with testosterone implants (800 mg, approximately 6 month intervals). Patients were classified as having a congenital, childhood, or post-pubertal onset, as well as according to the adequacy of treatment prior to their first DEXA scan as untreated, partially treated or well treated. RESULTS: Men with AD requiring regular ART (n = 169, aged 46.3+/-1.1 years, range 22-84 years) underwent a DEXA scan prior to being treated with testosterone implants (800 mg, approximately 6 month intervals). In cross-sectional analysis at the time of the first DEXA scan untreated men (n = 24) had significantly reduced age-adjusted BMD at all four sites (L1-L4, femoral neck, Ward's triangle and trochanter). Well-treated men (n = 77) had significantly better age-adjusted BMD at all four sites compared with those who were partially treated (n = 66) or untreated (n = 24) with their age-adjusted BMD being normalized. In a longitudinal assessment of men (n = 60) who had two or more serial DEXA scans, at the second DEXA scan after a median of 3 years, men who were previously partially treated (n = 19) or untreated (n = 11) had proportionately greater improvements in BMD, significantly for Ward's triangle (P = 0.025) and the trochanter (P = 0.044) compared with men (n = 30) previously well treated. CONCLUSIONS: The present study demonstrates a positive relationship between adequacy of testosterone replacement and BMD in men with overt organic AD. Additionally, the BMD of well-treated AD men approximates that of age-matched non-AD controls. The greatest BMD gains are made by those who have been either untreated or partially treated, and optimal treatment over time (median 3 years) normalizes BMD to the level expected for healthy men of the same age.