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Biomedical subjects

B Day

Publications and source records attributed to B Day.

At least 37 records · Page 2Linked to original sources
PubMed1995

Arthroscopy of the elbow: anatomy, portal sites, and a description of the proximal lateral portal.

Cadaveric studies were carried out to evaluate the safety and value of the standard portals used in elbow arthroscopy. The dissections were performed in 12 fresh cadaveric specimens. Each portal was assessed in terms of its safety with respect to nearby important structures. A proximal lateral portal was evaluated and has subsequently been used in 62 patients. A straight posterior (transhumeral) portal was also studied. We have found that in arthroscopy of the elbow joint, the proximal approaches (proximal medial and proximal lateral), are safer than the anteromedial and anterolateral approaches. All areas of the anterior compartment can be visualized using these two portals, and we recommend that they be the standard anterior portals used in elbow arthroscopy. All of the posterior approaches are safe.

Arthroscopy↗
PubMed1994

Contraction of the guinea pig isolated, perfused trachea to purine and pyrimidine agonists.

Unlike methacholine and histamine, ATP and uridine 5'-triphosphate (UTP) are more potent contractile agonists when they are applied to the mucosal (intraluminal, IL) surface of the guinea pig perfused trachea than when they are applied to the serosal (extraluminal, EL) surface. The relative contractile activities of a series of purine and pyrimidine compounds were assessed. The order of EL activity was: [2-methythio ATP (2 MeSATP) = adenosine 5'-diphosphate (ADP)] > [adenosine 5'-O-(2-thiodiphosphate) (ADP beta S) = ATP = adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S)] > [(beta, gamma-imido ATP) (APPNP) = alpha, beta-methylene ATP (APCPP)] > [UTP = uridine 5'-diphosphate (UDP) = inosine 5'-triphosphate (ITP)] > [xanthosine 5'-triphosphate (XTP) beta, gamma-methylene ATP (APPCP)]. EL adenosine, adenosine 5'-monophosphate, uridine 5'-monophosphate and uridine were weak or inactive. The EL order of activity, therefore, shares some characteristics of P2Y receptors. The order of IL activity was: (ATP = UTP = ITP) > (ATP gamma S = ADP = APPNP = 2 MeSATP) > (UDP = ADP beta S = XTP) > APCPP; the other compounds were weak or inactive. The IL order of activity, therefore, resembled that for P2U or "nucleotide receptors." ATP, APPNP, UTP, UDP, ITP and XTP were more active when added to the IL than after administration to the EL bath; the remaining compounds were similarly active EL and IL, or were more active EL than IL. Greater IL than EL activity of agonists was a property associated with preference for P2U-receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1993

The neuropathy of elderly mice.

The aim of this study was to define morphological and neurophysiological features of an age-related neuropathy in mice and to explore possible underlying pathogenetic mechanisms. Teased-fibre analysis of sciatic nerves in aged animals demonstrated a high incidence of demyelination. Electron microscopic analysis of sciatic nerve also revealed axonal atrophy. Both forms of pathology preferentially effect large myelinated fibres. The morphological evidence suggests that demyelination may have resulted from two processes; a primary event and a late consequence of axonal shrinkage. A high-affinity ouabain-binding form of (Na+,K+)ATPase was found in both mice sciatic nerve and spinal roots. A progressive and ultimately severe reduction of enzyme concentration with age was demonstrated in sciatic nerve and dorsal root. Since no change with age was seen in fast (anterograde or retrograde) axoplasmic flow, reduced peripheral nerve (Na+,K+)ATPase is not due to impaired enzyme translocation. Motor nerve conduction velocity decreased significantly with age, while minimum F-wave latency and somatosensory evoked potential latency increased. Impaired conduction velocities in aged animals may be attributed to the interaction of many factors including demyelination, remyelination, a disproportionate loss of large myelinated fibres, axonal atrophy, nerve regeneration and reduced peripheral nerve (Na+,K+)ATPase. It is concluded that the neuropathy in senescent mice is not species specific and is less severe, even in long-lived mice species, compared with that seen in the rat.

Aging↗
PubMed1992

Triazolam.

Explore the source record for details and available documents.

New Zealand↗
PubMed1992

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.

Action Potentials↗
PubMed1992

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.

Apraxias↗
PubMed1991

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)

Arthroscopy↗
PubMed1991

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.

Action Potentials↗
PubMed1990

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.

Arthroscopy↗
PubMed1989

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.

Arthroscopy↗
PubMed1989

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.

Adolescent↗
PubMed1985

The medical profession and nuclear war. A social history.

Since World War II, individual physicians and medical organizations in the United States have cooperated with the federal government in preparing for nuclear war. While most physicians have maintained a neutral stance, a minority have resisted federal policies. Health professionals participated actively at the wartime laboratories that developed the atomic bomb and in the medical research that followed Hiroshima and Nagasaki. Professional organizations helped with civil defense planning for nuclear conflict during the Cold War of the late 1950s and early 1960s. Medical resistance to nuclear war began in the same period, gained wide attention with the growth of Physicians for Social Responsibility in the early 1960s, declined during the Vietnam War, and vastly increased in the early 1980s. Activism by health professionals usually has responded to government policies that have increased the perceived risk of nuclear conflict. The recent return of civil defense planning has stimulated opposition in medical circles. Ambiguities of medical professionalism limit the scope of activism in the nuclear arena. These ambiguities concern the interplay of organized medicine and government, tensions between science and politics, and the difficulties of day-to-day work in medicine while the arms race continues.

American Medical Association↗
PubMed1985

Excessive reduction in peripheral resistance during exercise and risk of orthostatic symptoms with sustained-release nitroglycerin and diltiazem treatment of angina.

Acute effects of placebo, sustained-release nitroglycerin, diltiazem capsules, and the combination of both drugs were monitored in nine stable angina patients. They were randomized to receive either placebo or 13 mg of slow-release nitroglycerin orally (double-blind). This was followed in 1 hour by 120 mg of diltiazem orally, given to all patients (unblinded). Invasive hemodynamic measurements were made before and after each treatment at supine and sitting rest, two levels of submaximal, and at maximal exercise and twice in recovery. Compared to the control test at maximal exercise, sustained-release nitroglycerin increased aerobic capacity 24%, lowered peripheral resistance -32%, and lowered systemic pressure -23%, while the respective changes with placebo were -3%, 5%, and 2%. When diltiazem was added to placebo compared to the control test, there was a 4% increase in oxygen consumption and -9% and -4% reduction in systemic resistance and systemic pressure, respectively. The addition of diltiazem to nitroglycerin was associated with a 20% increase in oxygen consumption a -42% reduction in systemic resistance and a -32% reduction in systemic pressure. Two patients who received nitroglycerin plus diltiazem experienced symptomatic hypotension, while one patient who received placebo plus diltiazem experienced hypotension. These side effects caused the study to be terminated prematurely. Thus, although the combination of nitroglycerin and diltiazem had a greater effect on afterload than either drug alone, the combination did not provide greater improvement in cardiac performance.

Aged↗
PubMed1985

The vascular and nerve supply of the human meniscus.

Twenty-three fresh, cadaver knees were studied to evaluate details of the vascular and nerve supply of the menisci in humans. Vascularity was investigated using dye and latex injections, and the nerve supply was studied microscopically using a variety of special stains. Vessels arise mainly from medial and lateral inferior and middle geniculate arteries. Radial branches from a perimeniscal plexus enter the meniscus at intervals, with a richer supply to the anterior and posterior horns. Vessels supplying the body are limited to the peripheral one-third, except in the fetus. There is an avascular area adjacent to the popliteus tendon. The perimeniscal tissue is richly innervated. Most nerves are associated with vessels. Smaller nerves and axons run radially in convoluted patterns. Single axons course through the perimeniscal tissue, and many nerves are seen in the interstitial tissue of the outer one-third of the meniscus and in the anterior and posterior horns. The inner two-thirds has no nerve fibers.

Aged↗
PubMed1985

Long-term monotherapy of angina pectoris with diltiazem.

Eighteen patients with exertional angina were treated with diltiazem (360 mg/day). Serial exercise testing was performed and the results were compared to evaluations when patients were receiving placebo at the initiation and termination of the study. Serial exercise tests indicated significant improvement in duration of exercise (+18%, p less than 0.001), time to 1 mm ST depression (+32%, p less than 0.005), and time to angina (+46%, p less than 0.001) when patients were receiving diltiazem. During diltiazem treatment, there was a significant reduction in myocardial oxygen demand as indicated by the change in submaximal pressure rate product. This may contribute to the beneficial effect of diltiazem in patients with exertional angina. The reduction in pressure rate product was due primarily to a change in heart rate. This study provides evidence that diltiazem is an effective long-term monotherapy for angina; no evidence of drug tachyphylaxis was apparent after a total of 16 months treatment with diltiazem.

Aged↗