Motor-related functional subdivisions of human lateral premotor cortex: epicortical recording in conditional visuomotor task.

OBJECTIVE: To clarify the functional subdivisions of the human lateral premotor cortex (PM) in the visuomotor control. METHODS: Event-related potentials (ERPs) were epicortically recorded from PM in 5 epilepsy patients. S1-Go/NoGo choice delayed reaction time (RT), S1-warned S2-Go simple RT and control fixation paradigms were compared using paired visual stimuli (S1, S2). RESULTS: Signal-related activity peaked at 176-194 ms after S1 in the ventrorostral PM (PMvr) in all 3 paradigms, indicating its role in signal perception. Early set-related activity was recorded with its peak <810 ms after S1 in the dorsorostral PM (PMdr) and was larger in the choice than in the simple RT paradigm, suggesting its role in signal selection. Its cognitive component was recorded as surface-positive transients at PMdr, while its motoric aspect, seen as negative transients, extended to the caudal PM. Late sustained set-related activity was observed in preparation for hand movement in the caudal PM at the hand and face positive motor areas. After presentation of S2, movement-related activity was observed at the hand sensorimotor area for motor execution, following the signal-related activity at PMvr. CONCLUSIONS: The present ERP study suggests the temporally sequential representation of predominantly 'cognitive' function in the rostral PM and 'motor' function in the caudal PM. SIGNIFICANCE: The rostrocaudal cognitive-motor gradient was demonstrated in the lateral premotor cortex in humans by means of an epicortical ERP approach.     

MESENCHYMAL HAMARTOMA OF THE LIVER – AN AUTOPSY CASE WITH SERIAL SECTIONS AND SOME COMMENTS ON ITS PATHOGENESIS

An autopsy case of mesenchymal hamartoma of the liver was reported and from the macroscoplcal observation and serial sections of the tumor the following findings were found: (1) macroscopically the tumor is supplied by only one large triad, (2) in the tumor hepatic lobular structure is fundamentally preserved and proliferated bile ducts with surrounding fibrosis and many bile thrombi are mainly elongated and dilated Hering's canals, (3) the cysts connect with dilated interlobular bile ducts, (4) there are two portions, where connection of bile ducts is incomplete, that Is, from Hering's canals to interlobular bile ducts and from interlobular ducts to large ducts in the large triad of (1), (5) almost all portal veins in the large triad of (2) are stenosed or obliterated by loose intimal fibrosis. From these findings it is considered that intrahepatic bile duct obstruction resulting in regional biliary cirrhosis is the fundamental process of this disease, and in addition the role of hemodynamic disturbance was discussed.     

Physical Therapy (93)

Intertester reliability of the McKenzie evaluation in assessing patients with mechanical low back pain. (Sunny Brook & Women's College Health Sciences Centre, Toronto, Ontario, Canada) J Orthop Sports Phys Ther 2000;30:368–389. In this study, patients were assessed simultaneously by 2 physical therapists trained in the McKenzie evaluation system. The therapists were randomly assigned as examiner and observer. Agreement was estimated by Kappa statistics. Forty‐five subjects (47 ± 14 years), composed of 25 women and 20 men with acute, subacute, or chronic low back pain were examined. The agreement between raters for selection of the McKenzie syndromes was K = 0.70, and for the derangement subsyndromes was K = 0.96. Interrater agreement for the presence of lateral shift, relevance of lateral shift, relevance of lateral component, and deformity in the sagittal plane was K = 0.52, 0.85, 0.95, and 1.00, respectively. Intertester agreement on syndrome categories in 17 patients under 55 years of age was excellent with K = 1.00. Conclude that a form of low back evaluation, using patterns of pain response to repeated end range spinal test movements, was highly reliable when performed by 2 properly trained physical therapists. Comment by Karen Crawford, RPT. This article intends to address the ability for therapists to agree on a low back pain diagnosis using the McKenzie technique of classification. It is important for this study to select a clear clinical diagnosis in order to establish rationale for patient management and determine a prognosis. Another purpose for this study was to agree on the relevance of sagittal and frontal plane deformities using McKenzie methods in assessing patients with back pain. The subjects included adult patients with a history of acute, subacute, or chronic low back pain. Patients were referred by general practitioners or specialists for treatment at an outpatient department where the study was conducted. The examination consisted of taking a history, observational evaluation of the range of motion, and completion of a specified tests movements in the sagittal, frontal, and combined planes. Subjects were allowed to communicate only with the assessor. A total of 46 patients with a history of low back pain agreed to complete the assessment. Patients were divided into 2 groups, those 55 years of age and older and those younger than 55. McKenzie identifies only 3 mechanical syndromes: 1. Postural, 2. Dysfunction, 3. Derangement. Each of these syndromes were divided into separate subsyndromes according to location of the pain and presence or absence of spinal deformities. The study concluded that therapists trained in use of the McKenzie evaluation system can be highly reliable in reaching the same conclusion in respect to classifying patients into diagnostic syndromes and subsyndromes, especially in patients under the age of 55. In contrast to other published studies, the importance of advanced training for interpretation of symptom behavior definitely leads to selection of the correct diagnosis.     

Factors Influencing the Improvement of Gait Ability After Total Hip Arthroplasty

We aimed to investigate the factors influencing gait improvement in the patients who had undergone total hip arthroplasty. We performed gait analysis on 43 female patients with unilateral hip osteoarthritis. All the patients were analyzed before and at 2, 6, and 12 months after the surgery. There were significant reductions in spatiotemporal parameters in the patients with hip osteoarthritis compared with the control group. The mean values of the spatiotemporal parameters of the patients showed considerable improvement by 12 months after surgery; however, they did not reach the same values as those observed in the healthy subjects. The stage of osteoarthritis and the changes in the leg-length discrepancies were the factors that most influenced gait improvement after total hip arthroplasty throughout the follow-up period.     

Neuropathological study of the role of mast cells and histamine‐positive neurons in selective vulnerability of the thalamus and inferior colliculus in thiamine‐deficient encephalopathy

The purpose of the present study was to examine the role of histamine in the pathogenesis of experimental thiamine‐deficient encephalopathy. By studying sagittal serial sections the authors were able to examine the topographical relationship between histamine‐positive neurons and fibers, the number of mast cells, and localized lesions in the thalamus (TH) and inferior colliculus (IC). Adult rats were given a thiamine‐deficient diet and pyrithiamine was given intraperitoneally (30 µg/100 g bodyweight per day), and the distribution of vulnerable regions and petechial bleeding was histologically examined by reconstruction of the sagittal serial sections. The distribution of mast cells and histamine‐positive neurons and fibers was examined immunohistochemically in control rats, and compared between the vulnerable and non‐vulnerable regions of the TH and tectum. Changes in the aforementioned measures during the thiamine‐deficient state were also examined. The blood–brain barrier was examined using antibodies against rat endothelial barrier antigen (EBA) and albumin. The density of histamine‐positive fibers in the vulnerable regions of the TH and IC was very low and not different from the non‐vulnerable regions, and the number of mast cells was significantly higher in the lateral portion of the TH than the medial portion of the TH. The numbers of mast cells increased on days 7–10 after the start of the experiment, and significantly decreased on days 14–21. Histamine‐positive neurons and fibers in the TH and IC also had the same changes. Bleeding of the IC occurred exclusively around arteries, and perivenous bleeding was absent. Albumin exudation and suppression of EBA expression of capillaries were found in the spongy lesions of the TH and IC. The role of histamine in selective vulnerability of the TH and IC in experimental thiamine‐deficient encephalopathy was not supported. Findings in the present study suggest that the spongy change is a primary event, and vascular changes are secondary.