Low-intensity pulsed ultrasound improves spinal fusion.

BACKGROUND CONTEXT: Increasing the incidence of solid bony fusion is a primary goal in spine surgery. Daily low-intensity pulsed ultrasound therapy has been shown to improve and accelerate the bone healing process. PURPOSE: The purpose of this study was to evaluate the efficacy of daily low-intensity pulsed ultrasound therapy to improve the rate and quality of spinal fusion. STUDY DESIGN: Canine fusion model prospective study. PATIENT SAMPLE: Fourteen adult male dogs were used. OUTCOME MEASURES: Radiographic grading of plain films, computed tomography (CT) and magnetic resonance imaging (MRI), gross palpation, torsional stiffness and histologic grading were used to determine the presence or absence of fusion. METHODS: Posterior noninstrumented bilateral fusions were evaluated at the L2-L3 and L5-L6 levels. Treatment with low-intensity pulsed ultrasound for 20 minutes per day over the fusion site (stimulated) was compared with fusion sites that received no stimulation (nontreated controls) at 6 and 12 weeks after surgery. Plain film radiographs, CT and MRI, mechanical torsion testing and histologic examination were performed. RESULTS: At 6 weeks, ultrasound treated sites were more frequently fused compared with nontreated controls, although the difference in fusion rate was not statistically significant. At 12 weeks after surgery complete radiographic and histologic fusion occurred in 100% of ultrasound-treated sites. In the nontreated control sites 78% had achieved complete radiographic fusion and 44% had complete histologic fusion. Compared with control sites, the histological and mechanical fusion rate was significantly greater in ultrasound-treated sites (P<.05) at 12 weeks. A statistically significant increase in mechanical stiffness in ultrasound-treated sites was also found at 12 weeks after surgery. CONCLUSIONS: Low-intensity pulsed ultrasound therapy may be a useful means to ensure successful spine fusion.     

The Albert Dock Hospital, London: the original site (in 1899) of Tropical Medicine as a new discipline.

The London School of Tropical Medicine, and indeed the 'new' discipline of tropical medicine, originated in 1899 at the Albert Dock Hospital - situated in London's east-end. The founder of the discipline was Patrick Manson - with a great deal of political assistance from the British Secretary of State for the Colonies (Joseph Chamberlain). The hospital (originally opened in 1890) was rebuilt in 1937-1938 and ultimately demolished in 1993.     

Cyclophosphamide cardiotoxicity in bone marrow transplantation: a prospective evaluation of new dosing regimens

Cyclophosphamide (CY) cardiotoxicity may be a lethal complication of bone marrow transplantation. Previous echocardiographic studies have reported that left ventricular dysfunction due to CY occurs in over 50% of patients undergoing transplantation. To evaluate the cardiotoxicity of new dosing protocols that included twice-daily rather than once-daily CY, 44 bone marrow transplantation patients were prospectively evaluated with serial ECGs and echocardiograms. Twenty-six patients received a once-daily lower-dose protocol (mean total 87 +/- 11 mg/kg), and 18 patients received a twice-daily higher-dose (mean total 174 +/- 34 mg/kg) CY regimen. In the higher-dose CY group, significant reductions in summed ECG voltage (-20%) (P less than .01) and increases in left ventricular mass index (LVMI) (+10%) (P less than .05) were detected in the first week following therapy. These changes resolved by the third week following CY and were significantly greater than the changes noted in the lower-dose group. However, left ventricular ejection fraction (EF) did not change significantly in either group. Five patients developed clinical cardiotoxicity (four, pericarditis; one, congestive heart failure); four of the five patients were in the higher-dose group (P = .14). Only a prior history of congestive heart failure or a baseline EF less than 50% was an independent correlate of clinical cardiotoxicity (P less than .05). Thus, dose-dependent cardiotoxicity following the use of CY for bone marrow transplantation is evident as reversible decreases in ECG voltage and increases in left ventricular mass, possibly reflecting myocardial edema or hemorrhage. However, systolic dysfunction is much less common with these new twice-daily dosing regimens when compared with earlier studies of high-dose once-daily CY.     

Nonosmotic diabetic cataracts

It has been suggested that sugar cataracts associated with diabetes mellitus result from the accumulation of excess sorbitol within lens fibrils. Swelling of lens fibrils occurs when water moves in to maintain osmotic balance; the excess water causes disruption of fibrils and cataract formation. Other studies have indicated that more than sorbitol-induced osmotic stress is involved. Our study used lenses collected from rats after 21 or 44 d of streptozotocin diabetes. Cataracts formed in untreated 44-d streptozotocin diabetic rats, but were not apparent in the 21-d untreated diabetic animals. Lens sorbitol increased in the diabetic animals both before and after cataract formation. Lens taurine varied inversely with the sorbitol content in a fashion that resulted in no net change in total lens osmoles. Lens water did not increase in the diabetic animals with or without cataracts. The aldose reductase inhibitor Sorbinil prevented the increase in lens sorbitol in both the 21- and 44-d streptozotocin diabetic rats; cataract formation was prevented in the 44-d diabetic animals. The lens water in untreated diabetic animals with cataracts did not differ from lens water in the Sorbinil-treated diabetic animals that did not develop cataracts. Sorbinil treatment of diabetic animals was associated with normalization of both lens sorbitol and taurine levels. Taurine has been shown to serve both as an osmoregulator and as an antioxidant. The apparent increase in lens osmolality attributed to sorbitol was counterbalanced by an equimolar reduction in taurine concentration. The reciprocal relationship between taurine and sorbitol reduces the likelihood of an osmotic mechanism for sugar cataractogenesis; the reduced lens taurine, however, may increase the risk of lens protein oxidation and subsequent cataract formation. Thus in vivo sugar cataract formation may be an oxidative process rather than an osmotic phenomenon.     

Comparisons of plasma and salivary cortisol determinations for the diagnostic efficacy of the dexamethasone suppression test

The current status of the saliva dexamethasone suppression test (DST) is discussed and results from the literature reviewed. Evidence is presented that demonstrates that the efficacy of the salivary-based test is equal to that of the plasma DST provided that specifically developed radioimmunoassays are used for determination of salivary cortisol. Such evidence relied on measurement of cortisol in 300 matched samples of plasma and saliva provided by patients admitted to a routine psychiatric ward over a 2-year period. The results according to diagnosis (DSM-III categories) were in line with those generally reported. The influence of anticholinergic medication was examined: this had no significant effects on the performance of the plasma or salivary-based DST.     

Doppler umbilical and uterine flow waveforms in severe pregnancy hypertension

Doppler studies of the umbilical and uteroplacental bed arterial flow velocity waveforms were performed in a series of women suffering from severe proteinuric pregnancy hypertension. Ninety-five women were studied and the mean interval between the last study and delivery was 1.4 days. An abnormally elevated umbilical artery systolic:diastolic (AB) ratio was present in 61 (64%) of the women. All 10 perinatal deaths were associated with pregnancies with an abnormal umbilical artery AB ratio. An elevated umbilical artery AB ratio was significantly associated with small-for-gestation and neonatal morbidity. Infants associated with extremely high umbilical artery AB ratios (greater than or equal to 99th centile) spent twice as long in the neonatal nursery as those with a lower value. There was no relation between the duration of hypertension and the umbilical study result. The uteroplacental bed artery flow velocity waveform did not correlate with fetal or neonatal mortality or morbidity. Patients with abnormal uteroplacental AB ratios also had abnormal umbilical artery AB ratios. We conclude that an abnormal fetal umbilical artery Doppler flow velocity waveform correlates with adverse fetal outcome in severe proteinuric pregnancy hypertension and suggest that the associated placental lesion may precede the maternal hypertension.