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Biomedical subjects

D Grob

Publications and source records attributed to D Grob.

At least 109 records · Page 6Linked to original sources
PubMed1990

Posterior occipito-cervical fusion in rheumatoid arthritis.

The instability of atlanto-axial subluxation remains a challenging problem in patients with rheumatoid arthritis. In order to preserve as much function of the cervical spine as possible, inclusion of the occiput into the fusion should exclusively be performed when there is a radiologically or clinically manifest pathological condition of the atlanto-occipital joint or marked upward migration of the dens axis. In order to prevent irreversible damage to the spinal cord, an early indication of surgical stabilization is recommended. This article presents a retrospective analysis of the clinical and radiological results of occipito-cervical fusion in 26 patients with rheumatoid arthritis using a modified Brattström technique. The complications encountered were mainly due to the use of wire fixation, reinforcement using bone cement and insufficient reduction of atlanto-axial subluxation.

Adult↗
PubMed1990

Detection of HIV antibody and antigen (p24) in residual blood on needles and glass.

There is a significant rate of percutaneous injury with needles during the care of patients with acquired immunodeficiency syndrome (AIDS). Following puncture injury, it is recommended that the source of the contaminating blood be checked, and if human immunodeficiency virus-type 1- (HIV-1)-seropositive, zidovudine prophylaxis be considered. As the source of contaminating blood may be unknown, we studied the detectability of HIV-1 antibody and circulating antigen (p24) in the residual blood from needles and pieces of glass at various intervals following exposure to blood. The residual volume of blood remaining in needles varied from 183 +/- 50 microliters for a 20 G needle to 7.8 +/- 1 microliter for a 27 G needle, and the residual blood on small pieces of glass varied from 23 microliters for a piece weighing 558 mg to 2 microliters for a piece weighing 21 mg. Analysis of washed samples of residual blood from all 20 G through 26 G needles and from broken pieces of glass larger than 0.41 g that had been exposed to HIV-1-seropositive blood and left at room temperature for one hour, one day and one week resulted in positive tests for HIV-1 antibody by enzyme-linked immunosorbent assay (ELISA), immunofluorescence and Western blot assays. The circulating antigen was detected in residual blood of 20 G through 26 G needles, but not from contaminated pieces of glass. This technique could be applied to situations where a healthcare worker pricked him- or herself with a needle or with a piece of glass that had been contaminated with blood of unknown seroreactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Western↗
PubMed1990

Motor-evoked potentials in patients with cervical spine disorders.

Measurements of motor-evoked potentials by means of fractionated magnetic stimulation of motor pathways to the upper limbs was performed as part of the clinical assessment in 268 patients with cervical spine disorders. Seventy-two percent of the 127 patients with degenerative changes of the cervical spine, 67% of the 55 patients with rheumatoid arthritis (RA), and 57% of the 51 patients with trauma of the cervical spine showed a pathologic delay of central motor latency (CML). The data suggest that this method has a high sensitivity and therefore is recommended in the diagnosis of cervical spine disorders in patients with suspected compression of neural structures.

Adolescent↗
PubMed1990

The neurologic workup in patients with cervical spine disorders.

Care must be exercised in interpreting the clinical and radiologic findings when assessing patients with cervical spondylosis and involvement of neural structures for surgery. If the clinical picture cannot logically be explained by the radiologic findings, further investigation is indicated to exclude a coexistent disorder. Investigations may include electrophysiologic tests, transcranial magnetic stimulation, cerebrospinal fluid (CSF) analysis, and magnetic resonance imaging (MRI). Only then can the indication for surgical intervention be properly determined.

Aged↗
PubMed1990

Phenotypic and functional characterization of T cells from patients with myasthenia gravis.

A study of cell surface phenotypes of PBL of myasthenia gravis (MG) patients showed that their T cells had a significantly higher percentage of 4B4+ T cells (the helper/inducer subset) than age- and sex-matched controls. The PBL of MG patients proliferated significantly higher than those of normal subjects (NS) in response to the purified alpha chain of the acetylcholine receptor (AChR). Anti-AChR antibody was present in sera of 88% of MG and none of the NS. The PBL B cells from MG only, when cultured with autologous T cells and stimulated with either pokeweed mitogen (69%), or AChR-alpha chain (38%), secreted antibody to AChR-alpha chain, whereas T and B cells alone secreted no antibody. T cells from PBL of MG patients were more readily cloned than T cells of NS, by limiting dilution, in the presence of recombinant IL-2 and in the absence of AChR-alpha chain. About 50% of T cell clones from MG patients, compared to none from NS, proliferated to AChR-alpha chain. This response was HLA-DR restricted. MG T cell clones did not display significant cytotoxic activity, as compared to control T cell clones. Our results indicate that in MG, 4B4+ regulatory T cells play their role in the pathogenesis of MG, not by cytotoxicity, but more likely by their ability to stimulate specific antibody production by B cells.

Adult↗
PubMed1989

Role of the immune response in Sindbis virus-induced paralysis of SJL/J mice.

The pathologic role of the specific immune and inflammatory responses to viral infections of the CNS was investigated by using mice which are susceptible (SJL/J) and resistant (C57Bl6 and BALB/c) to the development of experimental autoimmune encephalomyelitis (EAE). Intracerebral inoculation of 10(4) PFU of Sindbis virus (SV) into 6- to 8-wk-old SJL/J mice resulted in a severe and sometimes fatal encephalomyelitis. A mild to severe hind leg paralysis was observed around days 6 to 7 postinfection (pi) which closely resembled EAE stages and persisted for up to 8 wk pi. Immunosuppression with cyclophosphamide on day 4 alleviated the severity of this disease. Significant perivascular and parenchymal infiltration was present in the brains and spinal cords of SV-infected SJL/J mice for up to 1 mo. This apparent immunopathologic reaction was found to be a characteristic of SJL/J mice, because infection of 6- to 8-wk-old BALB/c and C57Bl6 mice with SV did not cause paralytic disease. These mice also exhibited a significantly milder cellular infiltrate which was mostly resolved on day 12 to 14 pi. Titers of virus in the brain and spinal cords of mice were comparable with clearance by day 7 pi. SV-specific lymphoproliferation and serum antibody responses were also comparable in all mice. SV-infected SJL/J mice developed antibodies to myelin components as demonstrated in Western blots and responded to myelin basic protein by lymphoproliferation. Lymph node cells from these mice, after in vitro challenge with myelin basic protein, transferred a mild EAE-like disease to naive recipients and potentiated subclinical EAE into a severe disease.

Animals↗
PubMed1989

Osteoblastoma of the cervical spine. Case report.

This case report demonstrates the importance of an exact workup in unclear neck pain. An osteoblastoma situated in the pedicule of C6 is described. During 36 months there was no diagnosis made. Only by a CT-scan a tumorous lesion in the pedicule of C6 with the histology of a benign osteoblastoma was found. The therapy consisted in excision of the tumor of C6. A fusion was added because important parts of the joint were involved.

Adult↗
PubMed1989

Effect of Cleistanthus collinus leaf extract on neuromuscular function of the isolated mouse phrenic nerve-diaphragm.

Cleistanthus collinus is a toxic plant whose leaves have been used for homicidal or suicidal purposes. Since the toxic effects include muscle cramps and weakness, the effect of the leaf extract on the electrical and mechanical responses to nerve and muscle stimulation was studied in the isolated phrenic nerve-diaphragm preparation of the mouse. Following a 1 hr exposure to 0.015% leaf extract, the response of the compound nerve action potential to supramaximal nerve stimulation was reduced by 38%. The compound muscle action potential was reduced by 97%, and isometric tension by 99%. In response to direct muscle stimulation the compound muscle action potential and isometric tension were reduced by 38%. There was only an 11% reduction in resting membrane potential, but a 51% reduction in the amplitude of miniature endplate potentials. Endplate potentials could be evoked by nerve stimulation without prior treatment of the muscle with curare or a high concentration of magnesium. These studies indicate that the leaf extract markedly inhibits muscle contraction by reducing excitability of the nerve and muscle membranes, and by blocking neuromuscular transmission, without affecting excitation-contraction coupling or contractility of the muscle fibers.

Action Potentials↗
PubMed1989

Functional evaluation of the spinal cord by magnetic resonance imaging in patients with rheumatoid arthritis and instability of upper cervical spine.

Thirty-four patients with atlanto-axial instability due to rheumatoid arthritis were examined with plain x-ray views and functional magnetic resonance imaging (MR), and were neurologically evaluated. Transcranial brain stimulation was performed in 25 patients. In 22 cases, the authors observed inflammatory tissue thicker than 3 mm behind the odontoid peg. The spinal canal diameter was significantly decreased in the flexed position. Nine patients showed signs of cranial migration of the axis. The diameter of the spinal cord was measured to be 7.4 mm in the neutral position, and 6.5 mm in flexion. The difference between the diameter of the neutral and flexed positions was highly significant. Twelve of the 34 patients displayed clinical signs of cervical myelopathy, and 13 showed a significant delay of central motor latency, as calculated from the motor evoked potentials. Surgical intervention, either by a posterior approach only or combined with a transoral dens and inflammatory tissue resection, is recommended in patients with progressive atlanto-axial instability, pathologic clinical and neurophysiologic findings, and a spinal cord diameter of less than 6 mm in flexion. Severe pain and cranial migration of the axis, as measured by the MRI, also justify a surgical intervention.

Adult↗
PubMed1988

Functional diagnostics of the cervical spine using computer tomography.

35 healthy adults and 137 patients after cervical spine injury were examined by functional CT. The range of axial rotation at the level occiput/atlas, atlas/axis and the segment below were measured in all subjects. A rotation occiput/atlas of more than 7 degrees, and C1/C2 more than 54 degrees could indicate segmental hypermobility, a rotation at the segment C1/C2 less than 29 degrees to hypomobility. According to the postulated normal values based upon a 98% confidence level, out of 137 patients examined after cervical spine injury and with therapy-resistant neck pain, 45 showed signs of segmental hypermobility of the upper cervical spine, 17 showed hyper- or hypomobility at different levels, 10 patients presented segmental hypomobility at C1/C2 level alone. In all patients, according to the clinical assessment, functional pathology was suspected in the upper cervical spine. Surgical correction of rotary instability should be considered as a possible therapeutic procedure after successful diagnostic stabilisation of the cervical spine by minerva cast.

Adolescent↗
PubMed1988

Effects of repeated doses of intravenous immunoglobulin in myasthenia gravis.

The authors administered repeated courses of intravenous immunoglobulin (IVIg) to nine patients at the onset of an exacerbation of generalized myasthenia gravis (MG). Anticholinesterase medication (nine patients) and corticosteroid dosage (six patients) had been kept constant for a 2-month period. Six patients received two courses, two patients received three courses, and one patient received five courses. Twenty of 23 courses resulted in satisfactory improvement beginning 4.3 +/- 1.2 days after start of IVIg and becoming maximal 8.2 +/- 2.0 days, with sustained improvement lasting 106.6 +/- 49.1 days. Vital capacity increased from an average of 1845.1 +/- 489 cc to 2894 +/- 762 cc (p less than 0.01) at peak effect. Four of nine patients had a decrease in strength before improvement. There was no significant change in acetylcholine receptor antibody titers before or after therapy. Side effects were minimal. Of the three patients who had nonsatisfactory course, two responded well to additional IVIg. IVIg can produce repeated beneficial effects in patients with MG and may be useful as an adjunct in the management of MG.

Adolescent↗
PubMed1988

Transfusion-associated-graft-vs-host disease in a presumed immunocompetent patient.

Since the advent of bone marrow transplantation, a vexing clinical problem is that of acute graft-vs-host disease (GVHD). A less well-recognized disorder is that of GVHD in patients receiving blood products containing immunocompetent lymphocytes. Transfusion-associated (TA)-GVHD has a lower incidence and higher mortality (greater than 90%) than bone marrow transplantation-GVHD and until now has been limited to patients with hereditary or acquired immunologic deficits and to patients immunocompromised by chemotherapy for malignant neoplasms. We presently describe a patient who underwent coronary artery bypass graft surgery and who suffered what we believe was TA-GVHD. This diagnosis is supported by considering the chronology of events (in particular, blood transfusion), clinical features (fever, rash, abnormal results of liver function tests, diarrhea, and pancytopenia), and a skin biopsy specimen that revealed basal cell vacuolation and lymphocyte satellitosis that are considered characteristic for this disorder. We believe TA-GVHD can occur in previously immunocompetent patients who receive transfusions of blood products containing functioning lymphocytes and that this awareness will lead to the discovery of additional cases and a better understanding of this disorder.

Acute Disease↗
PubMed1988

Determination of left ventricular wall thickness and muscle mass by intravenous digital subtraction angiocardiography: validation of the method.

Left ventricular (LV) wall thickness and muscle mass are important measures of LV hypertrophy. In 24 patients LV end-diastolic wall thickness and muscle mass were determined (two observers) by digital subtraction angiocardiography (DSA) and conventional LV angiocardiography (LVA). Wall thickness was determined over the anterolateral wall of the left ventricle according to the technique of Rackley (method 1) or by planimetry (method 2). Seventeen patients were studied at rest and seven during dynamic exercise. Wall thickness correlated well between LVA and DSA; the best correlations were obtained by a combined subtraction mode using either method 1 or 2 (method 1, r greater than or equal to 0.80; method 2, r greater than or equal to 0.75). The standard error of estimate of the mean (SEE) was slightly lower for method 2 (less than or equal to 10%) than for method 1 (less than or equal to 13%). DSA significantly overestimated wall thickness by 5-7% with method 1 and underestimated by 12-14% with method 2. Muscle mass correlated well between LVA and DSA; the SEE was less than or equal to 15% for method 1 and less than or equal to 12% for method 2. Overestimation of muscle mass by DSA was 7-11% with method 1 and underestimation was 13-15% with method 2. It is concluded that LV wall thickness can be determined accurately by DSA with an SEE ranging between 10 and 13%. Determination of LV muscle mass is slightly less accurate and the SEE is slightly larger ranging between 13 to 17%. With method 1, wall thickness and muscle mass were overestimated and with method 2 underestimated.

Adult↗
PubMed1987

Adverse cardiovascular effects of anticholinesterase medications.

Anticholinesterase medications (anti-ChEs) play a significant role in the diagnosis and treatment of myasthenia gravis (MG). The primary effect on the heart produced by a surfeit of ACh is bradyarrhythmias with consequent fall in cardiac output and hypotension; yet, adverse cardiac reactions to these agents have been reported relatively infrequently. The authors describe 12 patients with MG from a pool of more than 1,000 who suffered hypotensive episodes related to use of anti-ChEs. The 12 patients (seven male, five female) had a mean age of 62.6 years; of these, eight adverse reactions occurred after edrophonium, two after neostigmine, and two after pyridostigmine. Seven patients had a recent increase in anti-ChEs and none had a decrease in dosage. Nine patients suffered either from severe sinus bradycardia, (20 beats/min), junctional bradycardia, or complete AV dissociation. Two patients had paradoxic sinus tachycardia and all had syncopal or near-syncopal episodes. Evidence for cholinergic stimulation of other organs was generally lacking. No recurrence appeared with reduction of the dose of anti-ChEs or discontinuation of the drug. The authors believe that these agents should be given with caution to patients with inflammatory, infiltrative, or degenerative disease of the conduction systems, patients being treated with digitalis, calcium-channel antagonists or beta blockers, patients with myocardial ischemia, and elderly patients. Appropriate resuscitative equipment should be readily available.

Adult↗