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Biomedical subjects

R Segal

Publications and source records attributed to R Segal.

At least 127 records · Page 7Linked to original sources
PubMed1991

Herniated L4-L5 disc after placement of Harrington instrumentation for a fracture of the thoracolumbar spine.

The authors report a case in which L5 radiculopathy developed acutely after surgery for placement of Harrington rod instrumentation for an L1 body fracture. Computed tomographic myelography demonstrated a large L4-L5 herniated disc that had not been present in preoperative studies. An emergency laminectomy was performed, and a large, free, subligamentous disc fragment was removed. The patient subsequently regained L5 sensorimotor function. The postoperative development of lumbar radiculopathy is an uncommon complication of Harrington rod instrumentation that may result from several biomechanical features of the instrumentation. These injuries may not be detected by intraoperative monitoring of somatosensory evoked potentials, and therefore, the postoperative neurological examination assumes a crucial role in the early diagnosis of these lesions. As our case demonstrates, these radicular deficits may be reversible if their cause is promptly recognized and treated.

Aged↗
PubMed1991

The use of visible light-curing resin for vertebral body replacement.

The technology of visible light-curing resin has recently been developed for use in removable prosthodontics. A quartz halogen lamp producing a 400- to 500-nanometer wave-length spectrum of visible light is used to polymerize high-molecular-weight acrylic resin monomers. While several in vitro and in vivo studies of visible light-curing resin are found in the dental literature, no studies have yet been performed to evaluate it as an intracorporeal implant in surgery. The authors have designed a rat model of microcervical corpectomy to assess vertebral body replacement with visible light-curing resin in comparison to conventional autopolymerizing methyl methacrylate. Spinal cord function tests, spinal-implant stability assessments, and histological evaluations were made in a total of 41 rats at 2, 4, or 6 months postimplant. No animal developed a neurological deficit or radiographic instability, and at sacrifice there was no evidence of implant fracture-extrusion. In addition, there were no signs of adverse reaction in the surrounding tissues. Morphological investigation of the resin/bone interface at 6 months revealed very good implant anchorage. Visible light-curing resin was found to be far superior to methyl methacrylate for construction of spinal implants. Its waxy consistency makes it easy to handle. It remains pliable until light is applied, allowing adjustments in shape for a well-fitted implant without time constraints. Applied in layers, adjustments can be made even after polymerization of a previous layer. This new implantable resin will allow safer, immediate stabilization in patients with neoplastic destruction of the spine, and may also be advantageous for other neurosurgical applications, such as cranioplasty.

Animals↗
PubMed1991

Assessment and treatment of a pediatric patient in chronic care: ethnographic methods applied to occupational therapy practice.

Ethnographic methods were used to examine how an experienced occupational therapist assesses and treats a pediatric patient within a relatively long-term clinical relationship. Treatment goals for this preverbal child with Hirschsprung disease, who began occupational therapy at 22 months of age, included (a) introduction of oral feeding to reduce dependence on total parenteral nutrition through intravenous feeding and (b) facilitation of exploratory play, which had been developmentally delayed during extensive periods of immobilization during medical care. This article shows how the meaning of therapeutic activities changes for the patient over time, as the occupational therapist builds trust through affect attunement, validates his or her empathic interpretations, and develops common understandings with the patient's family and others within the social and cultural contexts of chronic care.

Activities of Daily Living↗
PubMed1991

Regulatory T cell activity specific to human type II and III collagens in rheumatoid arthritis.

Fifty-one patients with rheumatoid arthritis (RA) were examined for their immune response potential to human collagen type II and III. It was found that T cells of 57% of patients with RA proliferated to collagen type III whereas only 27% of T cells of patients with osteoarthritis (OA) and healthy controls responded to this antigen by proliferation (p less than 0.04). A lower percentage (38%) of patients with RA had proliferative responses to collagen type II in comparison to 17% of responders in healthy controls. The capability to produce T cell helper factors specific to collagen type III was found to be significantly higher in patients treated with nonsteroidal antiinflammatory drugs (NSAID) (60%) in comparison to patients with OA (16%) and healthy controls (13%). Immunoregulatory drugs affected the specific T helper function in response to collagen type III but did not change the proliferative responses to collagen type II and III in patients with RA. HLA analyses revealed a significant difference in the frequency of HLA-DRw10 between our sample of patients with RA and healthy controls.

Antibody Formation↗
PubMed1991

Effect of spa therapy in Tiberias on patients with rheumatoid arthritis and osteoarthritis.

Forty-one patients with rheumatoid arthritis were treated for 2 weeks at a Tiberias spa hotel. Randomized into 2 groups, Group 1 received a combination of mineral baths and mud packs, and Group 2 had tap water baths only. Both groups had a significant but temporary improvement in Ritchie index. Group 1 showed a significant improvement in grip strength. No improvement was noticed in morning stiffness, 15 meter walk time and laboratory variables of disease activity in either group. Twelve patients with osteoarthritis (OA) received 2 weeks of treatment with mineral baths and mud packs. Statistically significant improvement for a period of 6 months was noticed in night pain, pain on passive motion, tenderness on palpation and in the index of severity of OA of the knee.

Arthritis, Rheumatoid↗
PubMed1990

Rescue of interleukin-1 activity by leucovorin following inhibition by methotrexate in a murine in vitro system.

We have recently shown that methotrexate (MTX) inhibits interleukin-1 (IL-1) activity in vitro. This effect may play an important role in the rapid antiinflammatory action of MTX in rheumatoid arthritis. In the present study, we showed that the inhibition of IL-1 activity in vitro by MTX is dependent on folate pathways since, after the addition of leucovorin, the inhibitory effect of MTX was abolished. These findings may shed more light on the mechanism of action of MTX in rheumatoid arthritis. They also point to the fact that some IL-1 activities may be dependent on intracellular folate pathways.

Animals↗
PubMed1990

The effect of ascaridole on the in vitro development of Plasmodium falciparum.

Ascaridole is a terpene isolated from the plant Chenopodium ambrosioides (American wormseed); it is one of the few naturally occurring endoperoxidases. Artemisinin, which also belongs to this group, is a potent antimalarial. We therefore undertook a study to determine the effect of ascaridole, a known anthelmintic, on the in vitro development of Plasmodium falciparum. Ascaridole was found to be a potent inhibitor of plasmodial growth; after 3 days, development was arrested by a drug concentration of 0.05 microM, and at 0.1 microM no parasites were visible in the culture. At lower concentrations the effect was observed mainly at the trophozoite stage, whereas the ring stage was marginally affected. However, even at these lower concentrations, the ring culture could not continue normal development and ceased to grow at a later stage. The peroxide group is essential for the antimalarial activity of ascaridole, as judged from the fact that cineol, which bears an epoxide group instead of the peroxide group found in ascaridole, was totally inactive at identical concentrations.

Animals↗
PubMed1990

Methotrexate: mechanism of action in rheumatoid arthritis.

Most studies of immune function in rheumatoid arthritis (RA) patients treated with methotrexate (MTX) show only marginal effects on humoral or cellular immune responses. These include measurements of lymphocyte subsets, proliferative responses to mitogens, immunoglobulin production, rheumatoid factor and immune complexes. The mechanism of action of MTX in RA might be more antiinflammatory than immunosuppressive. This is supported by the rapid clinical response to drug treatment and by data from in vitro and animal studies. The inhibition of interleukin-1 (IL-1) activity or other inflammatory cytokines by MTX may play an important role in the antiinflammatory effect of MTX. MTX effects in RA are not fully understood and further studies are needed to clarify its mechanism of action. MTX has crucial effects on the cascade of events initiated by some cytokines (IL-1, IL-6, tumor necrosis factor), which plays a major role in RA and other inflammatory diseases.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Median nerve injury from local steroid injection in carpal tunnel syndrome.

Local steroid injections for symptomatic relief of carpal tunnel syndrome have become common in the evaluation and treatment of this disorder; yet reports of median nerve injection injury from this practice are rare. We present a case of nerve injury from a steroid injection in a 24-year-old man with carpal tunnel syndrome that was successfully treated by division of the transverse carpal ligament and neurolysis. The histopathological characteristics of the lesion are presented, and the pathogenesis and treatment of this injury are discussed. Means of avoiding this complication include careful attention to anatomic landmarks as well as to the patient's subjective response during injection and avoidance of the use of local anesthetics.

Adult↗
PubMed1990

Changes in serum CPK, LDH, and their isoenzymes in the perioperative period in patients undergoing craniotomy.

The perioperative changes in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 were determined during craniotomy in order to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction and malignant hyperthermia. Twenty-eight male patients, 29 to 76 years of age (mean +/- SD = 58 +/- 13.2 years), undergoing craniotomy for tumor reseaction (n = 26) or cerebral artery aneurysm clipping (n = 2) were included in this study. Ten serial blood samples were obtained from each patient: one sample before and another after induction of anesthesia, and eight samples after the incision, over a period of 70 h. The preinduction serum CPK level of 97 +/- 32 U/L (mean +/- SD) increased gradually and significantly and reached the peak level of 542 +/- 116 U/L 34 h after incision (p <0.05). Whereas all of the CPK isoenzymes increased in terms of U/L after incision, only the MM fraction (expressed as percent of total CPK) increased, and the MB and BB fractions (expressed as percent of total CPK) decreased. The preinduction serum LDH level of 150 +/- 42 U/L (mean +/- SD) increased gradually after incision and reached the peak level of 210 +/- 32 U/L 58 h after incision (p <0.05). LDH2 as a percent of total LDH decreased significantly, but the LDH1/LDH2 ratio did not change. LDH4 and LDH5, as percents of total LDH, increased significantly. The large increases in total serum CPK and the concomitant decrease in MB percent after craniotomy may minimize and/or mask the percentage increase in the MB level following acute myocardial infarction. The perioperative serum CPK level as a marker in the diagnosis of malignant hyperthermia should be interpreted in light of the present results and in conjunction with clinical symptomatology.

Journal Article↗
PubMed1990

Anti-DNA idiotype- and anti-idiotype-specific T cell responses in patients with systemic lupus erythematosus and their first-degree relatives.

We examined the proliferative responses of T cells of patients with systemic lupus erythematosus (SLE), their first-degree relatives, and healthy donors, to a human monoclonal antibody that bears a common anti-DNA idiotype, 16/6 Id, and to a murine, 16/6 Id-specific, monoclonal antibody. Both 16/6 Id+ and 16/6 Id-specific antibodies were previously shown to be involved in the induction of experimental SLE in mice. Here we show that T cells of fewer SLE patients, as compared with healthy donors, could proliferate to both antibodies. The difference between T cell responses of patients and controls to the 16/6 was found to be significant. The proliferative responses of T cells of first degree relatives of SLE patients to the anti-16/6 Id were found to be significantly lower compared with the responses detected in healthy donors and in SLE patients. The responses of T cells of SLE relatives to the 16/6 Id were found to be lower than those of healthy donors, but this difference was not significant. The present study suggests a possible involvement of T cells, and specifically of idiotype and anti-idiotype specific T cells, in SLE.

Antibodies, Anti-Idiotypic↗
PubMed1990

Generalized pustular drug rash induced by hydroxychloroquine.

A 69-year-old man developed a generalized pustular drug rash 2 weeks after starting on hydroxychloroquine sulfate (HCQ) medication. This form of drug eruption had not previously been attributed to HCQ, although a diagnosis of pustular psoriasis cannot be ruled out.

Aged↗
PubMed1990

Therapeutic risk-assessment model for identifying patients with adverse drug reactions.

The association between factors that place patients at risk for adverse drug reactions (ADRs) and the occurrence of ADRs was examined, and a therapeutic risk-assessment model was developed. Theoretical risk factors for ADRs to digoxin and theophylline were identified through the literature by researchers at a private tertiary-care hospital. Data were then collected from two groups of 67 patient charts each during a 15-month period. One group of charts represented patients who had experienced an ADR to digoxin or theophylline. The other group represented matched control patients who had not experienced an ADR to either drug. ICD-9-CM (International Classification of Diseases, 9th Revision, Clinical Modifications) ADR codes were assigned by medical records department personnel, and the ADRs were verified by using the Naranjo algorithm. Seven risk factors for each drug were found to be significantly associated with ADRs. A serum digoxin concentration greater than 2.5 ng/mL and elevated blood urea nitrogen were the two best predictors of an ADR to digoxin. The probability of experiencing an ADR to digoxin was 94.1% for a patient with both of these risk factors. A serum theophylline concentration greater than 25 micrograms/mL was the greatest predictor of an ADR to theophylline; the probability of experiencing an ADR to theophylline was 85.2% if a patient had that risk factor. The sensitivity and specificity of the therapeutic risk-assessment model were 92.9% and 61.8%, respectively, for digoxin and 95.8% and 84.0%, respectively, for theophylline. Several laboratory-based screening criteria demonstrated an ability to predict ADRs to digoxin and theophylline.

Digoxin↗
PubMed1989

The effects of methotrexate on the production and activity of interleukin-1.

To explore the possibility that the mechanism of action of methotrexate (MTX) in rheumatoid arthritis (RA) is related to modulation of interleukin-1 (IL-1), the effects of MTX on IL-1 production and activity were evaluated. Human peripheral blood mononuclear cells and murine peritoneal and splenic cells were stimulated by lipopolysaccharide to produce IL-1. No inhibition of IL-1 synthesis or secretion caused by MTX treatment could be demonstrated either in vitro or in vivo, in patients with RA or in mice treated with MTX. We did show, however, that MTX had an inhibitory effect on IL-1 activity in 2 assays that demonstrate 2 different functions of IL-1. In a 2-step assay using LBRM-33-1A5 (1A5) and CTLD cells, MTX inhibited the secretion of IL-2 by 1A5 lymphoma cells in response to phytohemagglutinin and IL-1. In an assay using D10.G4.1 (D10) cells, MTX inhibited IL-1-induced proliferation of the D10 T cell clone. No effect of the drug on IL-2 activity was observed. The results demonstrate that MTX is capable of inhibiting some IL-1 activities without affecting IL-1 production or secretion. We propose that the inhibition of IL-1 activity or IL-1-dependent events may be one of the mechanisms of action of MTX in RA.

Animals↗
PubMed1989

Common variable immunodeficiency: a family study and therapeutic trial with cimetidine.

Various immunologic parameters were tested in a family of two patients with common variable immunodeficiency. Both patients had low serum immunoglobulin levels, low peripheral B cell and T4 subclass of lymphocytes, and reversed T4/T8 ratio. One of the patients had excessive suppressor activity. Two of the asymptomatic members of the family (the father and one brother) had also low T4/T8 ratio that was not associated with excessive suppressor activity. No linkage between the disease inheritance to HLA could be observed. A study of the T cell helper activity to an antigen, the response to which is regulated by an HLA-linked gene, suggested a defect in the immune response of the two patients and their asymptomatic brother with immunologic disorders. Treatment with cimetidine of the patient with excessive suppressor activity led to an improvement in his clinical state, reduction in suppressor activity, temporary effect on his proliferative response capacity to mitogens, and an increase in the antigen-specific helper activity.

Adult↗
PubMed1989

Serum creatine phosphokinase, lactic dehydrogenase, and their isoenzymes in the perioperative period.

The purpose of the present investigation was to determine the normal perioperative variations in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB, and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction or malignant hyperthermia. In 30 patients, 52 to 75 years of age undergoing elective orthopedic operations, 10 serial blood samples were obtained in the perioperative period: two samples before skin incision and eight samples after the incision over a time span of 70 hours. The preinduction mean serum CPK level of 141 U/L increased gradually and significantly and reached a maximum mean concentration of 809 U/L 34 hours after incision (p less than 0.01). The CPK-MM percent increased after incision, whereas that of CPK-MB and CPK-BB decreased, although their absolute values in terms of U/L rose. The preinduction mean serum LDH value of 173 U/L increased gradually after incision and achieved peak levels at 34 hours (203 U/L) and 58 hours (210 U/L) after incision (p less than 0.05). The LDH1:LDH2 ratio did not change. The LDH5 percent increased and peaked 10 hours after incision (p less than 0.05). There was a significant correlation between severity of operation-induced tissue damage and the serum CPK concentration (p less than 0.001). The large increase in total CPK (primarily MM fraction) occurring after surgery may minimize the percentile effects caused by an increase in MB level due to myocardial infarction.

Aged↗
PubMed1989

Synovial and serum levels of methotrexate during methotrexate therapy of rheumatoid arthritis.

Methotrexate (MTX) levels were studied following intravenous MTX in both serum and synovial fluid (SF) of rheumatoid arthritis patients. Two hours after injection serum MTX levels were higher than those of SF. At 24 hours SF levels of MTX exceeded those of the serum, while at 72 hours both blood and SF concentrations were undetectable. The localization of parenteral MTX in the SF may have importance in the understanding of its mechanism and site of action in rheumatoid arthritis.

Arthritis, Rheumatoid↗