Effect of heat or chemical treatment on leptospiral antigens.

The use of bacterins is one of the primary methods in the control of leptospirosis in domestic animals, especially cattle, swine, and dogs. Bacterins have been made using chemically treated or heat-inactivated organisms. Many of the initial studies indicated that the bacterins gave complete protection, whereas later reports found that some inactivation methods resulted in bacterins that protect against death but not against kidney infection and renal shedding. This raised the possibility that some of the antigens had been altered. To investigate this possibility, we heat or chemically treated Leptospira interrogans serovar icterohaemorrhagiae CF-1, L. interrogans serovar canicola Moulton, L. interrogans serovar grippotyphosa SC4397, L. interrogans serovar hardjo Hardjoprajitno, and L. interrogans serovar pomona MLS. Temperatures used to determine alterations in antigens were 50, 56, 80, 100, and 121 degrees C. The chemicals used were formaldehyde, phenol, and thimerosal. Analysis was done using Laemmli gels and Western blots. We found that heating at 50 or 56 degrees C had the smallest effect on antigens, whereas heating at 80 or 100 degrees C caused the appearance of high-molecular-weight bands on Western blots. Heating at 121 degrees C caused almost all the bands to disappear, in both the stained gel and the Western blot. Both phenol and Formalin treatment altered proteins, whereas thimerosal treatment appeared to have little effect compared with heating at 50 degrees C.     

Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG.

OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation.     

Mechanisms responsible for the thermal sensitivity of adrenal microsomal monooxygenases.

Studies were done to determine the mechanism(s) responsible for the thermal lability of adrenal microsomal monooxygenases. Preincubation of guinea pig adrenal microsomal suspensions at 37 degrees C caused large time-dependent declines in benzo(a)pyrene (BP) hydroxylase and benzphetamine (BZ) demethylase activities. Similar preincubations with hepatic microsomes had little effect on enzyme activities. The decreases in adrenal enzyme activities were completely prevented by co-incubation of microsomes with cytosol, but were not diminished by reduced glutathione, ascorbic acid, or bovine serum albumin. Partial protection was afforded by EDTA, suggesting that lipid peroxidation might be involved, but malonaldehyde production was not demonstrable and MnCl2, a potent inhibitor of lipid peroxidation, did not affect the decline in enzyme activities. The decreases in the rates of BP and BZ metabolism were prevented by including NADPH or NADP+ in the preincubation medium. The preincubation conditions causing losses of adrenal enzyme activities did not affect cytochrome P-450 concentrations or substrate binding to cytochromes P-450, as indicated by type I difference spectra. NADH-cytochrome c reductase activity also was not affected, but there were decreases in NADPH-cytochrome c reductase activity that were proportionately similar to the declines in drug-metabolizing activities. Direct assessment of NADPH-cytochrome P-450 reductase revealed similarly large decreases in enzyme activity resulting from preincubation of adrenal microsomes. The results demonstrate a need for extra caution when doing preincubation experiments with adrenal microsomal preparations, and suggest that the thermal lability of adrenal monooxygenases is attributable to effects at the active site of NADPH-cytochrome P-450 reductase.     

Changes in bladder function following a surgical alteration in outflow resistance

The changes in bladder function occurring after a surgical alteration in bladder outflow resistance were studied in 20 males undergoing transurethral prostatectomy (TURP) and in 20 females undergoing an endoscopic bladder neck suspension (EBNS). Serial cystometrograms (CMG) were performed before operation, and on alternate days after spontaneous micturition was re-established, for 5 days in the males and for 21 days in the females. CMGs were repeated at 3 months and 1 year after operation. After TURP voiding pressures (P_det) fell rapidly from a mean of 118 cm H₂O before operation to 57 cm H₂O at 5 days, with an increase in flow rate during this time from 10.5 ml/s to 24 ml/s. Detrusor instability that had been present in 14 patients resolved within 2 days in 12. There was no further significant urodynamic change over the 1-year study period. After EBNS, there was an early rise in voiding pressure (P_det rose from 26 cm H₂O before operation to 42 cm H₂O at 3 days). This continued to increase up to 21 days particularly in those patients with initial large residuals. Three patients developed detrusor instability. Flow rates were greatly reduced at first (27 ml/s before operation and 13 ml/s at 3 days), and gradually increased in line with voiding pressures, yet were still diminished 1 year after operation. The urodynamic changes following a reduction in bladder outflow resistance by TURP are immediate and sustained and unlikely to be the result of structural changes within the bladder wall. EBNS produces an increase in outflow resistance and it can be several weeks before balanced voiding is achieved, with significantly increased detrusor pressures needed to achieve complete bladder emptying at a reduced flow rate.     

Case report 733

Calcific tendinitis at the site of origin of the rectus femoris muscle is a rare lesion. Presumed to be formed by deposition of hydroxyapatite crystals, this entity may be confused with other lesions such as os acetabuli or posttraumatic abnormalities. The characteristic location and appearance of the calcifications in a symptomatic patient with no history of trauma should allow diagnosis and subsequent symptomatic therapy.     

Normal and abnormal glenoid labrum: assessment with multiplanar gradient-echo MR imaging.

A retrospective study of magnetic resonance (MR) imaging of the glenoid labrum performed with multiplanar gradient-echo (MPGR) sequences was done to ascertain the different appearances of the normal labrum and the findings in patients with tears. MPGR images were obtained with a 1.5-T magnet in 37 shoulders of 16 healthy subjects and 19 patients with subsequent surgical evaluation. Increased intralabral signal intensity was seen in 12 of 26 normal shoulders (46%), and atypical morphology was seen in six shoulders (23%). Atypical morphology was present in eight of nine patients with labral tears. Deformity (n = 2 [22%]) and clefts (n = 2 [22%]) were seen in patients with tears. Deformity (n = 3 [12%]) and clefts (n = 1 [4%]) were occasionally seen in healthy subjects. Absence of the labrum and separation of the labrum from the glenoid cavity was present only in patients with tears; therefore, the labrum should be presumed torn in the presence of these findings. Increased intralabral signal intensity on MPGR images did not help predict labral integrity; morphologic findings were more predictive of labral tear.     

Differences in triage thresholds for patients presenting with possible acute coronary syndromes: more than meets the eye.

BACKGROUND: Many studies have shown differences in cardiac care by racial/ethnic groups without accounting for institutional factors at the location of care. OBJECTIVE: Exploratory analysis of the effect of hospital funding status (public vs private) on emergency department (ED) triage decision making for patients with symptoms suggestive of acute coronary syndromes (ACSs) and on the likelihood of ED discharge for patients with confirmed ACS. STUDY DESIGN AND SETTING: Secondary analysis of data from a randomized controlled trial of 10,659 ED patients with possible ACS in five urban academic public and five private hospitals. The main outcome measures were the sensitivity and specificity of hospital admission for the presence of ACS at public and private hospitals and the adjusted odds of a patient with ACS not being hospitalized at public versus private hospitals. RESULTS: Of 10,659 ED patients, 1,856 had confirmed ACS. For patients with suspected ACS, triage decisions at private hospitals were considerably more sensitive (99 vs 96%; p<.001) but less specific (30 vs 48%; p<.001) than at public hospitals. The difference between hospital types persisted after adjustment for multiple patient-level and hospital-level characteristics. CONCLUSION: Significant differences in triage for patients with suspected ACS exist between public and private hospital EDs, even after adjustment for multiple patient demographic, clinical, and institutional factors. Further studies are needed to clarify the causes of the differences.     

Occupational factors related to shoulder pain and disability.

OBJECTIVES: To determine, in a population based study, the influence of occupational factors on the occurrence of shoulder pain and disability. METHODS: A random sample of patients was selected from the register of a general practice in the Greater Manchester area of the United Kingdom. Information was collected by a posted questionnaire with specific enquiries about symptoms in the shoulder region and related disability. A lifetime occupational history was obtained including physical exposures, working conditions, and psychosocial aspects of each workplace. Analysis has been conducted as a case-control study, comparing occupational exposures at the time of onset of symptoms in those with shoulder pain and disability with corresponding occupational exposures in those without shoulder pain and disability. RESULTS: An increased risk of shoulder pain and disability in men was associated with carrying weights on one shoulder (relative risk (RR) 5.5, 95% confidence interval (95% CI) 1.8 to 17), whereas those who reported working with hands above shoulder level, using wrists or arms in a repetitive way, or stretching down to reach below knee level had about twice the risk of shoulder pain and disability. Men working frequently in very cold or damp conditions had a fourfold and sixfold risk respectively of shoulder pain and disability. Reporting of shoulder pain and disability was also more common among men and women who reported that their work caused a lot of stress (RR 1.9, 95% CI 0.9 to 4.1) or was very monotonous (RR 2.7, 95% CI 1.3 to 5.4). The relations between physical exposures, working conditions, and psychosocial factors were independent. CONCLUSIONS: This population based study has shown that physical activities carried out at work, the physical conditions under which the work is conducted, psychosocial aspects of work, or the working environment are all independently related to the occurrence of shoulder symptoms and disability, emphasising the multifactorial nature of this condition.     

Pulse oximetry. Application in the labor-and-delivery unit of a tertiary care center.

Pulse oximetry is a noninvasive early warning system capable of alerting the nursing and medical staff of the occurrence of arterial hemoglobin desaturation and resultant hypoxemia. This technology has already achieved widespread use intraoperatively, in the recovery area and in medical and surgical intensive care units. Application during labor and delivery, another acute care setting often involving emergency conditions, is a logical extension. We applied this technology in the labor-and-delivery suite. The degree of arterial desaturation (absolute percent) and range of values appear greater in pregnancy than in the pregnant woman's healthy, nonpregnant counterpart.