Reduction in LBNP tolerance following prolonged endurance exercise training.

Eight young men underwent an 8-month endurance exercise training program. Prior to and following the training program, the subjects' maximal oxygen uptake (VO2max), total blood volume (TBV) and plasma volume (PV), tolerance to lower body negative pressure (LBNP) assessed by the cumulative stress index (CSI) to presyncope, and their hemodynamic responses to 0 to -45 torr LBNP was determined. Hemodynamic measures included rebreathe carbon dioxide cardiac output (Qc), heart rate (HR), directly measured arterial blood pressures (ABP), and strain gauge determination of forearm blood flow (FBF) and leg volume changes (delta LgV). Calculated values of stroke volume (SV), forearm, vascular resistance (FVR), and peripheral vascular resistance (PVR) were made. Following training, each subject had an increased VO2max (mean = +27.4%, P < 0.001), TBV (mean = +15.8%, P < 0.02), and PV (mean = +16.5%, P < 0.02) and each subject had a decreased tolerance to LBNP (mean CSI = -24%, P < 0.001). Stepwise linear regression identified that the major factors to significantly predict the decreased CSI pre- to post-training were a reduced response of PVR to LBNP from -15 to -45 torr (Model R2 = 0.853), the delta TBV (model R2 = 0.981), and the greater post-training reduction in SBP to LBNP of 0 to -45 torr (model R2 = 1.0). These data suggest that physiologic adaptations associated with the increased VO2max and TBV resulting from a prolonged endurance exercise training program can alter the reflex control of vasomotion and cardiac output during LBNP and reduce the LBNP tolerance.     

The relationship of serotonin to depression in Parkinson's disease

We have previously reported a correlation between depression in patients with idiopathic Parkinson's disease and decreased concentrations of the cerebrospinal fluid content of the serotonin metabolite, 5-HIAA. To further examine this relationship, we repeated the study in a new cohort of patients while they remained on dopaminergic medications, conducted follow-up interviews and examinations in our original cohort, and conducted an open trial of the serotonin precursor, 5-hydroxytryptophan in a group of new patients with depression. We were again able to demonstrate a significant reduction in cerebrospinal 5-HIAA in depressed patients in comparison to controls and patients without depression. Demented patients with Parkinson's disease, particularly those with concurrent depression, had the lowest values of 5-HIAA. No new cases of depression occurred in our original cohort after 2 1/2 years of follow-up, and depression remitted following conventional or experimental treatment in four patients. Depression improved in six of the seven new patients following oral 5-hydroxytryptophan. Three of these patients allowed a repeat lumbar puncture, and the concentration of 5-HIAA increased following 5-hydroxytryptophan. These three studies support our hypothesis that depression in idiopathic Parkinson's disease is associated with a reduction in brain serotonin. However, it also suggests that other factors, biological or environmental, may be causal factors.     

Magnetic resonance imaging in the diagnosis of a psoas abscess

Identification of a psoas abscess is often a diagnostic challenge. In this case report the diagnosis and subsequent treatment of a psoas abscess previously suggested by computed tomography was greatly enhanced by magnetic resonance imaging.     

Cognitive impairment after stroke: frequency, patterns, and relationship to functional abilities.

Cognitive function was examined in 227 patients three months after admission to hospital for ischaemic stroke, and in 240 stroke-free controls, using 17 scored items that assessed memory, orientation, verbal skills, visuospatial ability, abstract reasoning, and attentional skills. After adjusting for demographic factors with standardised residual scores in all subjects, the fifth percentile was used for controls as the criterion for failure on each item. The mean (SD) number of failed items was 3.4 (3.6) for patients with stroke and 0.8 (1.3) for controls (p < 0.001). Cognitive impairment, defined as failure on any four or more items, occurred in 35.2% of patients with stroke and 3.8% of controls (p < 0.001). Cognitive domains most likely to be defective in stroke compared with control subjects were memory, orientation, language, and attention. Among patients with stroke, cognitive impairment was most frequently associated with major cortical syndromes and with infarctions in the left anterior and posterior cerebral artery territories. Functional impairment was greater with cognitive impairment, and dependent living after discharge either at home or nursing home was more likely (55.0% with, v 32.7% without cognitive impairment, p = 0.001). In a logistic model examining the risks related to dependent living after stroke, cognitive impairment was a significant independent correlate (odds ratio, OR = 2.4), after adjusting for age (OR = 5.2, 80 + v 60-70 years) and physical impairment (OR = 3.7, Barthel index < or = 40 v > 40). It is concluded that cognitive impairment occurs frequently after stroke, commonly involving memory, orientation, language, and attention. The presence of cognitive impairment in patients with strike has important functional consequences, independent of the effects of physical impairment. Studies of stroke outcome and intervention should take into account both cognitive and physical impairments.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

Reconstruction of the burned thumb.

The thumb accounts for 40 to 50% of hand function. Reconstruction of soft-tissue contractures include release and coverage with skin grafts or various local, regional, distant, or free flaps. Thumb length, so important for prehension and opposition, can be restored by phalangealization, pollicization, or toe-to-thumb transfer. Secondary techniques such as metacarpal distraction-lengthening or osteoplastic reconstruction are rarely indicated.     

Detection of mycobacterial DNA in pleural fluid from patients with tuberculous pleurisy by means of the polymerase chain reaction: comparison of two protocols.

BACKGROUND: The detection of mycobacterial DNA in clinical samples on the basis of the polymerase chain reaction is a promising approach for the rapid diagnosis of tuberculous infections. No consensus exists, however, about which protocols are most sensitive, and the usefulness of this approach in the diagnosis of tuberculous effusions has been assessed in few patients. METHODS: The sensitivity of two protocols was compared for the detection of DNA from Mycobacterium tuberculosis in samples containing known amounts of mycobacterial DNA and in DNA extracted from 15 tuberculous pleural effusions. The results obtained for pleural fluid have been compared with cytological findings and with results obtained by standard microbiological techniques. RESULTS: Mycobacteria could be detected by acid fast staining in none and by culture in three of the 15 pleural fluid samples. A protocol based on the detection of the IS6110 insertion element (which could detect one mycobacterial genome/sample reproducibly) gave a positive result in nine of the 15 tuberculous effusions, though some samples were only intermittently positive (p less than 0.05 compared with culture). In contrast, a protocol based on the detection of the gene coding for the 65 kD mycobacterial antigen (which could detect mycobacterial genomes only if there were at least 10/sample) gave a positive result in three of the 15 tuberculous effusions. Pleural fluid that was always positive with the amplification procedure detecting the IS6110 sequence contained more neutrophils (30% (SD 27%)) than samples that were intermittently positive or always negative (3% (3%)); mycobacterial DNA was never detected in the four samples containing less than 1% neutrophils. CONCLUSIONS: The amplification of the IS6110 insertion element represents a rapid and sensitive means of detecting M tuberculosis in tuberculous effusions. The enrichment of cells containing mycobacteria (possibly neutrophils) before DNA extraction may be required to improve the sensitivity of this approach.     

Chest tube thoracostomy.

Knowledge of the indications, placement, and management of chest tubes in the intensive care unit is essential for the care of the critically ill patient. Awareness of the complications and mechanical difficulties that can occur with chest tubes and their drainage systems is essential for the safe and effective use of these devices.     

Clinically versus laboratory photocured facings.

Acrylic and composite resin facings may fracture or become detached from the metal framework. Insufficient retention, abrasion and trauma are among the causes of these phenomena. Clinical and laboratory techniques have been developed to fabricate facings by means of light-curing composite systems such as the Dentacolor (Kulzer, Inc.) system. The effect of different polishing methods, obtained in both techniques using the same material, was studied with SEM on samples. Finishing and polishing procedures were accomplished using fine finishing diamonds, diamond burs and sof-lex discs. Smooth and lustrous surfaces were obtained with finishing discs, in contrast to techniques using other finishing instruments. Little or no difference in surface texture was observed between samples finished by clinical and those finished by laboratory techniques.