Biomedical subjects
B Day
Publications and source records attributed to B Day.
Comparison of electric and magnetic coil stimulation in the supraclavicular region.
We compared the compound motor action potentials (CMAPs) evoked in the biceps, triceps, and abductor digiti minimi (ADM) muscles by conventional electrical stimulation at Erb's point (EP), and by magnetic coil stimulation of the supraclavicular region in 11 normal subjects. We found that magnetic coil stimulation was less effective than conventional stimulation in activating motor fibers in the brachial plexus in 45% of the recordings analyzed. CMAP amplitudes greater than those obtained with EP electrical stimulation were seen in 16% of recordings with supraclavicular magnetic stimulation, and in 33% of recordings with cervical magnetic stimulation, indicating that EP electrical stimulation is submaximal in a large proportion of cases.
Mirror movements in the alien hand syndrome. Case report.
The alien hand syndrome has been associated with different descriptions of abnormal motor behavior. We report on two patients with transient left hemiparesis who remained with limb apraxia and were particularly impaired by a variety of involuntary skilled movements of their apractic limb. After the report and a review of the literature, we discuss the presence of one type of abnormal movement observed in this syndrome. These movements resemble the mirror movements seen in the normal development of motor control and in some pathologic conditions later. Their appearance in the alien hand syndrome seems to demand both intrahemispheric and interhemispheric motor pathway damage.
Evaluation of cartilage lesions by magnetic resonance imaging at 0.15 T: comparison with anatomy and concordance with arthroscopy.
Recent evidence suggests that pharmacological treatment may alter the rate of progression of cartilage damage in osteoarthritis (OA). However, a lack of accurate and precise noninvasive assessments of cartilage structure makes it difficult to answer this question directly with prospective clinical trials, prevents early diagnosis of OA and restricts assessment of treatment to evaluation of symptoms or joint function. It is important, therefore, to develop precise, noninvasive methods both for diagnosis of early OA before damage is extensive and irreversible and for evaluation of therapeutic effectiveness. Magnetic resonance imaging (MRI) allows for noninvasive, multiplanar body imaging which depends on proton density, flow, and the T1 and T2 relaxation times. Because these variables differ markedly among joint tissues, cartilage erosions are visible with MRI and it should be possible to quantify them. Our objective was to compare MRI with arthroscopy for assessing the depth of lesions in the articular cartilage of human knees to help develop and validate MRI for use in clinical trials designed to assess the effect of therapy on cartilage structure. In the first part of our study, the effect of the MRI pulse sequence variables on the images was evaluated by varying them systematically and comparing the anatomy seen with MRI with that seen at arthroscopy or arthrotomy and with the histology. In the second part, 31 patients were assessed with MRI before arthroscopy. The MRI were graded on a 4-point ordinal scale by 2 observers who were unaware of the clinical diagnosis and compared with findings at arthroscopy which were graded using the same scale.(ABSTRACT TRUNCATED AT 250 WORDS)
Magnetic stimulation of the human motor cortex: ipsilateral and contralateral facilitation effects.
Voluntary contraction of a muscle greatly increases the amplitude and decreases the latency of the motor potentials evoked by electromagnetic coil brain stimulation (facilitation). Facilitation has also been observed with contraction of a nearby ipsilateral and a contralateral homologous muscle. We studied these facilitatory relationships in 5 normal subjects in small hand, forearm and upper arm muscles using surface-recorded compound motor action potentials, single motor unit recordings, and post-stimulus time histograms. There was no evidence for spread of facilitation between any pair of muscles if the muscle from which motor evoked potentials (MEPs) were recorded was completely at rest during brain stimulation, although this sometimes required training to accomplish or could not be achieved. Thus, although spread of facilitation has been observed by others under these conditions, we did not find this effect. There may be significant interindividual variations in the degree of facilitatory spread.
Arthroscopic anatomy of the hip.
The arthroscopic anatomy of the hip has been studied using a number of portals. Both distraction and positioning are necessary to allow insertion of instruments, and to allow exposure of the important anatomical structures. The internal anatomy of the hip joint is described in detail based on the arthroscopic view from the different portals. This study helps orient those interested in arthroscopy of the hip.
Arthroscopic anatomy of the shoulder.
Arthroscopic anatomy of the shoulder was evaluated using cadaver dissections. The anatomical areas of clinical importance were documented both photographically and with illustrations. It is hoped this anatomical study will prove to be an aid to arthroscopists during their early experiences with shoulder arthroscopy.
Intraarticular bupivacaine (Marcaine) after arthroscopic meniscectomy: a randomized double-blind controlled study.
In this study, 79 patients undergoing arthroscopic meniscectomy were entered into a randomized double-blind controlled trial in which intraarticular bupivacaine (Marcaine), was compared with a saline placebo. Intraarticular bupivacaine was shown to be an effective and safe method of achieving analgesia after arthroscopic meniscectomy.
The treatment of severe action myoclonus.
Ten patients with severe disabling myoclonus were treated with clonazepam, sodium valproate, primidone and piracetam alone, or in different combinations. Electrophysiological assessment indicated a cortical origin for the myoclonus in every case. Considerable improvement of myoclonus was achieved with combinations of these drugs in all patients, but this was not possible with monotherapy. In one patient two drugs were necessary (clonazepam and piracetam); in the others more than two drugs were required. The combination of sodium valproate, clonazepam and primidone (3 patients), or piracetam, clonazepam and primidone (3 patients), or the four drugs together (3 patients) was necessary to provide substantial relief of myoclonus. Such polytherapy generally was tolerated well. The benefits of treatment continued for more than 1 year in all cases, although progressive underlying pathology often caused other increasing disability.
High-dose intravenous human immunoglobulin in chronic inflammatory demyelinating polyneuropathy.
We treated nine consecutive patients with chronic inflammatory demyelinating polyneuropathy (CIDP) with high-dose intravenous human immunoglobulin (HIG), and clinical recovery rapidly followed. Disability that had persisted for months or years was often reversed in days. There were no major adverse reactions to HIG infusions.
Increased femoral head vascularity after an iliopsoas muscle pedicle bone graft.
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Bone peg fixation in the treatment of osteochondritis dissecans of the knee joint.
Seventeen patients between 15 and 26 years of age, were treated for osteochondritis dissecans of the knee by bone peg fixation. The fragment is attached with 2 or 3 matchstick-size bone graft taken from the proximal tibia. The average follow-up period was 3.2 years, union of the fragment occurred in all cases, and results were rated excellent or good in 16 of 17 patients. Preservation of the normal contour of the distal femur and stabilization of the osteochondral fragment was achieved. Stimulation of local blood supply by bone grafting may have promoted healing and a second procedure for removal of pins or screws was unnecessary.
Circulatory changes in the hip after high femoral osteotomy.
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Intracellular sodium and potassium changes in vascular smooth muslce during hemorrhagic shock.
The vascular smooth muscle cell sodium and potassium changes occurring in hemorrhagic shock were studied in rats subjected to hemorrhagic shock at 30 millimeters of mercury for a two hour period. A new ion exchange method, based upon the substitution of lithium for extracellular sodium was used to measure the intracellular sodium and potassium. A significant rise in cell sodium and fall in cell potassium levels occurred. These changes suggest that vascular smooth muscle cell membrane function is impaired in hemorrhagic shock. The normal homeostatic vascular responses to hemorrhage may be significantly affected by these changes.
Compression fractures of the thoracic and lumbar spine from compensable injuries.
Compression fractures of the thoracic and lumbar spine have a worse prognosis than is commonly realized. A study of 142 patients with this type of injury reveals several important features which affect the long term prognosis in these injuries. Severe compression, comminution, disc space narrowing adjacent to the fracture site, a low anatomical level of the fracture site, a low anatomical level of the fracture, and body cast immobilization in those with mild or moderate type fractures, are some of the factors associated with persistent long term back problems.
Cell sodium and potassium changes in hemorrhagic shock measured by a lithium substitution method.
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