Reduction of embryonic intracellular pH: a potential mechanism of acetazolamide-induced limb malformations

The effects of acetazolamide on the developing rodent limb bud were postulated to result from a reduction of intracellular pH (pHi). Embryonic intracellular pH was calculated from transplacental distribution of the weak acid, 5,5'-dimethyloxazolidine-2,4-dione, in teratogenically sensitive (C57BL/6) and resistant (SWV) inbred mice. pHi was reduced by acetazolamide treatment in C57 embryos and limb buds but not in SWV samples. Acetazolamide teratogenesis can be exacerbated by coadministration of amiloride, presumably through inhibition of Na+/H+ exchange attributable to the latter agent. pHi reduction after such treatment was more profound than after acetazolamide alone, providing further support for the central hypothesis. pH was also reduced in other embryonic (embryo plasma) and extraembryonic compartments (exocoelomic fluid, amniotic fluid). pH changes in these compartments could also lead or contribute to abnormal development.     

Cup containment and orientation in cemented total hip arthroplasties

We reviewed the radiographs of 864 Charnley and STH (Zimmer) cemented total hip arthroplasties with a mean follow-up of seven years (maximum 16 years). Survivorship analysis was used to assess the correlation between radiographic performance and the bony containment or the coronal orientation of the acetabular cup. The cup orientation and containment were interrelated; all vertically oriented cups were completely contained, whereas 25% of more horizontal cups were only partially contained. Completely contained cups had significantly lower incidences of complete cement-bone radiolucency (p = 0.02) and of wear (p = 0.09). Vertically oriented cups had a lower incidence of continuous radiolucency than neutrally oriented cups, but this was not statistically significant (p = 0.25). Our results confirm the importance of complete bony containment, and also indicate that it is better to accept vertical orientation and obtain full bony coverage than to have a more horizontal orientation with partial containment.     

Serum bone-gla protein after fracture

Serum bone Gamma-carboxyglutamic acid (bone-gla) protein (BGP), a marker of bone formation, was measured in serial blood samples drawn from 14 patients who had fractured at least one of their tibial or femoral diaphyses and from two other patients who had sustained major trauma without fracture but who had been immobilized. A total of 85 samples were taken and analyzed during the first three months after the fractures occurred. Serum BGP significantly increased and positively correlated with the time that had elapsed after the fracture, with an average twofold increase after two months. The fracture site and the duration of immobilization had no influence on the serum BGP levels. Serum BGP levels from the two non-fractured cases increased in the first two weeks with no subsequent consistent trend. These data suggest that serum BGP increases one to two months after a major fracture, possibly as a manifestation of bone repair. Further studies are required to determine the potential clinical value of serum BGP in the management of such patients.     

Ultrasound evaluation of female urinary incontinence

Thirty women, 25 with incontinence and five asymptomatic volunteer control subjects, were evaluated urodynamically by a variety of techniques, including ultrasound cystourethrography. The ultrasound evaluation was found to be a helpful adjunct in diagnosis. In comparison with radiologic techniques it offers more safety, more comfort, more privacy, more viewing time, and less cost. Bladder and urethral morphology during voiding activity and the amount and direction of urethrovesical mobility are easily determined by utilizing ultrasound techniques.     

Long-term effect of estradiol implants on the female urinary tract during the climacteric

The incidence of lower urinary tract dysfunction increases during the climacteric, and there is embryological, biochemical and epidemiologic evidence to suggest that depleted estrogen status is at least partially responsible. Twelve climacteric women underwent full assessment before and 1 year after treatment with a 50 mg subcutaneous estradiol implant +5 mg norethisterone for 7 days per month. Assessment consisted of a symptoms questionnaire, midstream urine sample, uroflowmetry, videocystourethrography with pressure flow studies, and urethral pressure profilometry. Subjectively, only the symptom of nocturia significantly improved. There was no change in flow variables but there was a significant decrease in residual urine and the degree of bladder base descent. Cystometric capacity was slightly but significantly decreased, and two patients developed genuine stress incontinence whilst on treatment. Nonetheless, there was a significant improvement in urethral pressures at rest but not under stress. This effect was predominantly in the proximal urethra. These data do not support the contention that estrogen replacement therapy is beneficial for lower urinary tract dysfunction during the climacteric.     

Comparative toxicity of ethylene dichloride in F344/N, Sprague-Dawley and Osborne-Mendel rats

Studies were conducted to compare the toxicity of ethylene dichloride (EDC) in F344/N rats, Sprague-Dawley rats, and Osborne-Mendel rats. Ten rats/sex/group were exposed to EDC in drinking-water at 0, 500, 1000, 2000, 4000 and 8000 ppm for 13 wk. The highest concentration was limited by the maximum solubility of EDC in water (about 9000 ppm). In addition, F344/N rats (10/sex/group) were administered EDC in corn oil by gavage to compare toxicity resulting from bolus administration with that of continuous exposure in drinking-water. Gavage doses of EDC were within the range of total daily doses (in mg/kg body weight/day) resulting from exposure in drinking-water. EDC administered by gavage resulted in greater toxicity to F344/N rats than did administration of similar doses in drinking-water. All males receiving 240 and 480 mg/kg body weight and 9/10 females receiving 300 mg/kg body weight by gavage died before the end of the study. Necrosis of the cerebellum was observed in the brains of 3 males receiving 240 mg/kg body weight and 3 females receiving 300 mg/kg body weight. Hyperplasia and inflammation of the forestomach mucosa were observed in 8 male and 3 female rats that died or were killed in moribund condition. EDC caused minimal toxicity to F344/N, Sprague-Dawley and Osborne-Mendel rats at the drinking-water concentrations used in these studies; only female F344/N rats had EDC-related renal lesions. Based on mortality and EDC-related lesions, the no-effect levels for EDC administered by gavage to F344/N rats were 120 mg/kg body weight for males and 150 mg/kg body weight for females.     

Evaluation of cerebral perfusion from bypass arteries using selective intraarterial microsphere tracer after vascular reconstructive surgery.

BACKGROUND AND PURPOSETo detect areas of cerebral perfusion from bypass arteries after vascular reconstruction, we administered selective intraarterial microsphere tracer into the external carotid arteries and determined (via single-photon emission computed tomography [IA-SPECT]) whether the distribution of radiotracer matched the arteriographic distribution of contrast material as shown on external carotid angiograms.METHODSWe compared the extent of regional distribution of tracer after external carotid artery injection of 20 to 40 MBq of 99mTc-HMPAO or 99mTc-ECD with that of contrast medium on the external carotid angiograms in 582 cortical regions in 12 patients with atherosclerotic occlusive disease and in 18 patients with moyamoya disease.RESULTSMarked accumulation of tracer was found only in the expected, specific, newly developed areas of cerebral perfusion from bypass arteries. The regional distribution of tracer corresponded to that of contrast medium in 523 regions (90%) and did not correspond in 59 regions (10%). Significant overestimation of the distribution of contrast material relative to that of tracer was observed in the patients with moyamoya disease.CONCLUSIONSPECT showed slightly different distribution of tracer from that predicted by conventional angiography. IA-SPECT should enhance the analysis of newly developed areas of cerebral perfusion from the bypass arteries.     

Anatomic bases of tongue flaps

Summary The morphological structure of the lingual a. was studied in 50 dissected and 14 vascular cast specimens. The course of this artery is divided into 4 segments: the original segment, the segment within hyoglossus, the ascending and the horizontal segments of the deep lingual a. The root of the tongue is supplied by 2 to 3 root branches of the lingual a., the ascending palatine a. and the tonsillar a. The body of the tongue is nourished on average by 25 arterial branches from the deep lingual a. The ventral surface of the tongue, as well as the sublingual gland and the floor of the mouth, is supplied by the sublingual a. The termination of the lingual a. anastomoses with the submental branch of the facial a. to form the lingual frenal a. Except for a submucous arterial network on the dorsum of the tongue, all blood vessels are separated completely by the lingual septum, through which arterial anastomoses (2.0 mm in diameter) can be found occasionally.This work was supported by the National Natural Science Fund