Diffusion-weighted magnetic resonance imaging for demonstration of cerebral infarcts

Summary Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis. DWI is superior to T2WI in assessment of small cortical infarcts and cerebral infarction in patients with preexisting vascular lesions. DWI is not specific, so other causes like cerebral hematoma and encephalitis have to be considered.      

Role of Tyrosine Kinase in Desflurane-induced Preconditioning

Background: Short administration of volatile anesthetics preconditions myocardium and protects the heart against the consequences of subsequent ischemia. Activation of tyrosine kinase is implicated in ischemic preconditioning. The authors investigated whether desflurane-induced preconditioning depends on activation of tyrosine kinase.

Methods: Sixty-four rabbits were instrumented for measurement of left ventricular pressure, cardiac output, and myocardial infarct size (IS). All rabbits were subjected to 30 min of occlusion of a major coronary artery and 2 h of subsequent reperfusion. Rabbits underwent a treatment period consisting of either no intervention for 35 min (control group, n = 12) or 15 min of 1 minimum alveolar concentration desflurane inhalation followed by a 10-min washout period (desflurane group, n = 12). Four additional groups received the tyrosine kinase inhibitor genistein (5 mg/kg) or lavendustin A (1.3 mg/kg) at the beginning of the treatment period with (desflurane-genistein group, n = 11; desflurane-lavendustin A group, n = 12) or without desflurane inhalation (genistein group, n = 9; lavendustin A group, n = 8).

Results: Hemodynamic values were similar in all groups during baseline (left ventricular pressure, 87 +/- 14 mmHg [mean +/- SD]; cardiac output, 198 +/- 47 ml/min), during coronary artery occlusion (left ventricular pressure, 78 +/- 12 mmHg; cardiac output, 173 +/- 39 ml/min), and after 2 h of reperfusion (left ventricular pressure, 59 +/- 17; cardiac output, 154 +/- 43 ml/min). IS in the control group was 55 +/- 10% of the area at risk. The tyrosine inhibitors had no effect on IS (genistein group, 56 +/- 13%; lavendustin A group, 49 +/- 13%; each P = 1.0 vs. control group). Desflurane preconditioning reduced IS to 40 +/- 15% (P = 0.04 vs. control group). Tyrosine kinase inhibitor administration had no effect on IS reduction (desflurane-genistein group, 44 +/- 13%; desflurane-lavendustin A group, 44 +/- 16%; each P = 1.0 vs. desflurane group).     

Effects of halothane, sevoflurane and desflurane on the force-frequency relation in the dog heart in vivo

PURPOSE: Frequency potentiation is the increase in force of contraction induced by an increased heart rate (HR). This positive staircase phenomenon has been attributed to changes in Ca2+ entry and loading of intracellular Ca2+ stores. Volatile anesthetics interfere with Ca2+ homeostasis of cardiomyocytes. We hypothesized that frequency potentiation is altered by volatile anesthetics and investigated the influence of halothane (H), sevoflurane (S) and desflurane (D) on the positive staircase phenomenon in dogs in vivo. METHODS: Dogs were chronically instrumented for measurement of left ventricular (LV) pressure and cardiac output. Heart rate was increased by atrial pacing from 120 to 220 beats x min(-1) and the LV maximal rate of pressure increase (dP/dt(max)) was determined as an index of myocardial performance. Measurements were performed in conscious dogs and during anesthesia with 1.0 minimal alveolar concentrations of each of the three inhaled anesthetics. RESULTS: Increasing HR from 120 to 220 beats x min(-1) increased dP/dt(max) from 3394 +/- 786 (mean +/- SD) to 3798 +/- 810 mmHg sec(-1) in conscious dogs. All anesthetics reduced dP/dt(max) during baseline (at 120 beats x min(-1): H, 1745 +/- 340 mmHg x sec(-1); S, 1882 +/- 418; D, 1928 +/- 454, all P < 0.05 vs awake) but did not influence the frequency potentiation of dP/dt(max) (at 220 beats x min(-1): H, 1981 +/- 587 mmHg x sec(-1); S, 2187 +/- 787; D, 2307 +/- 691). The slope of the regression line correlating dP/dt(max) and HR was not different between awake and anesthetized dogs. Increasing HR did not influence cardiac output in awake or anesthetized dogs. CONCLUSION: These results indicate that volatile anesthetics do not alter the force-frequency relation in dogs in vivo.     

The Parkinson-Control study: a 1-year randomized, double-blind trial comparing piribedil (150 mg/day) with bromocriptine (25 mg/day) in early combination with levodopa in Parkinson's disease.

Dopamine agonists have been recommended as early treatment for Parkinson's disease (PD), alone or combined with levodopa. Piribedil is a non-ergot selective D(2)/D(3) agonist with alpha(2) antagonist properties shown to be effective in the treatment of PD. This 12-month international, randomized, double-blind trial aimed to assess the efficacy of piribedil 150 mg versus bromocriptine 25 mg, in early combination with levodopa in Stage I to III PD patients. Motor efficacy was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS III, Items 18-31) as improvement from baseline. Response rate was defined as a 30% improvement. Among the 425 randomly assigned patients, 178 were also included in a substudy on cognitive follow-up evaluated by a dysexecutive syndrome oriented battery. A relevant improvement in UPDRS III over the 12-month study duration was observed both in the piribedil and bromocriptine groups (-7.9 +/- 9.7 points from baseline versus -8.0 +/- 9.5; not significant [n.s.]) with a response rate of 58.4% and 55.3% (n.s.), respectively. Piribedil and bromocriptine resulted in similar improvement on all UPDRS III subscores. Piribedil patients required less levodopa dose increase than those on bromocriptine. Cognitive performance remained generally unchanged in both groups, with a significant effect of piribedil limited to the Wisconsin Card Sorting Test. An overall good tolerability of piribedil was observed. Early combination of piribedil 150 mg with levodopa resulted in significant long-term improvement of all motor symptoms in PD patients insufficiently controlled by levodopa alone. Taking into account both efficacy and acceptability in the long-term, piribedil proved in this bromocriptine controlled study to be an effective and safe treatment for PD.     

Pneumothorax and other lung diseases: effect of altered resolution and edge enhancement on diagnosis with digitized radiographs

Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).     

Minimized surgery for retinal detachments with segmental buckling and nondrainage. An 11-year follow-up.

A prospective study was conducted of 107 retinal detachments operated on between August 1979 and January 1980, with a complete follow-up period ranging from 11 years to 11.5 years. Proliferative vitreoretinopathy (PVR) stage C1 or C2 was seen in 16 detachments. Surgery consisted of cryopexy and segmental buckling (limited to the area of breaks) with nondrainage. Of the surgical procedures, 71% were radial buckles, 19% circumferential, and 10% radial combined with circumferential buckles. The primary reattachment rate was 92.6%, and 97% after reoperation. During the long-term follow-up period, redetachment occurred in 12.1% of the eyes: 5.6% were classified as early redetachments (between 2 and 4 months), and 6.5% as late redetachments (between 3 and 7 years). Early redetachment was caused by PVR, and late redetachment by new holes. After reoperation, reattachment occurred in 92.6% of the eyes. The predominant cause of final failure was PVR (3.7%). Only one eye had two reoperations. There was a highly significant (P less than 0.001) improvement between preoperative visual function (mean 0.32) and postoperative visual function (mean 0.56) in all 99 reattached eyes during the follow-up period (Mann-Whitney U test).