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Biomedical subjects

M J Javid

Publications and source records attributed to M J Javid.

36 records · Page 2Linked to original sources
PubMed1985

Vasomotor response to hormonal norepinephrine in canine cerebral and hindlimb vessels.

We calculated the percent change in initial vascular resistance during open loop intra-arterial infusions of norepinephrine (NE) in 12 acutely denervated isolated canine brains and 5 acutely denervated perfused hindlimbs. The studies were repeated on seven chronically denervated brains devoid of perivascular sympathetic fibers. All tissues were free of residual anesthetic. Half-maximal responses were obtained at similar plasma NE concentrations in both the control brains (ED50 13.1 +/- 3.8 X 10(-6) M) and hindlimbs (ED50 9.22 +/- 2.3 X 10(-6). The maximal response was much greater in the limb vasculature (490.3 +/- 30.1%) than in the cerebral vasculature (107.2 +/- 9.5%). A fourfold increase in cerebral vascular sensitivity was noted 3 days after sympathetic gangliectomy (ED50 3.44 +/- 0.74 X 10(-6) M), without any significant change in the maximal response (101.3 +/- 5.7%). Plasma levels of NE observed in resting dogs did not constrict either vascular bed; elevated levels of NE observed in stress dogs would minimally constrict limb vessels but not acute or chronically denervated cerebral vessels. These in situ results confirm that NE does not play a significant role as a physiological vasomotor hormone and suggest that prejunctional neuronal uptake of NE is not responsible for the observed differences in cerebral and hindlimb vascular response. Furthermore, it is unlikely that denervation hypersensitivity to circulating NE plays a role in pathological cerebral vasoconstriction (vasospasm) following subarachnoid hemorrhage.

Animals↗
PubMed1985

Chymopapain chemonucleolysis: correlation of diagnostic radiographic factors and clinical outcome.

The therapeutic response to treatment of lumbar disk herniation with chymopapain chemonucleolysis is significantly influenced by the criteria used for patient selection. Although careful clinical selection of patients reduces the frequency of treatment failure, some patients do not achieve satisfactory relief of pain with chemonucleolysis. In an attempt to identify objective pretreatment radiographic findings that might refine selection criteria and further reduce the failure rate of chemonucleolysis, a retrospective correlation of pretreatment radiographs and clinical responses was made of 200 consecutive chemonucleolysis patients. Marked improvement in sciatica occurred in 79.9% and 79.3% of patients at early and late follow-up, respectively. There was a significantly higher response rate, however, in patients who had definite radiographic evidence of focal disk herniation and in those patients with definite radiographic evidence of nerve-root compression (marked nerve-root deviation, nerve-root flattening or edema, root-sleeve amputation) by disk material. Those patients with a preinjection disk height greater than the mean had a slightly better response rate (91.1%) than those whose disk height was smaller than the mean (80.0%). Most cases of treatment failure could be attributed to an incorrect radiographic diagnosis, treatment of patients with equivocal diagnostic studies, the presence of "free" disk fragments, and causes of nerve-root compression unresponsive to chymopapain.

Adult↗
PubMed1985

Chymopapain chemonucleolysis: CT changes after treatment.

Chymopapain chemonucleolysis is now used extensively in this country to treat lumbar disk herniation. Despite increasing experience in patient selection, there continue to be patients who do not respond to treatment and require diagnostic reevaluation. Interpretation of postchemonucleolysis computed tomographic (CT) scans in these patients requires a knowledge of the CT changes that normally occur after treatment with chemonucleolysis. To define these temporal changes, a prospective CT evaluation was performed of 29 treated interspaces in 26 patients who returned for routine postchemonucleolysis follow-up. Despite a successful clinical response in 17 of 21 patients, changes in the size, location, shape, homogeneity, and density of the disk herniation were uncommon at the 6 week follow-up. In 24 treated interspaces, the most common changes at 6 week CT follow-up were the development of vacuum phenomenon in three (12.5%) and a slight decrease in the size of two (8.3%) disk herniations. A successful response was noted in 17 of 21 patients scanned at 6 month follow-up, with five (22.7%) of 22 injected interspaces exhibiting vacuum phenomenon and 13 (59.1%) interspaces showing an observable decrease in the size of the disk herniation. Early improvement of sciatica after chemonucleolysis often occurs without a change in the size of the disk herniation and may be mediated by chymopapain-induced disk-space narrowing. Continued improvement may be accompanied by both a decrease in the disk height and a reduction in the size of the disk protrusion.

Adult↗
PubMed1985

Efficacy of chymopapain chemonucleolysis. A long-term review of 105 patients.

A 9- to 12-year follow-up review was conducted in 105 of 124 patients who were treated with chymopapain chemonucleolysis for herniated lumbar disc. The data were obtained from responses to a questionnaire. Seventy-nine patients (75.2%) reported marked improvement, six (5.7%) had slight improvement, and 20 (19.0%) had no improvement. Of the 87 patients not receiving workman's compensation, 70 patients (80.5%) had marked improvement; four (4.6%) had slight improvement; and 13 (14.9%) had no improvement. Of the 18 compensation cases, nine patients (50.0%) had marked improvement; two patients (11.1%) had slight improvement; and seven patients (38.9%) had no improvement. These results are comparable to those reported for surgical discectomy, and confirm that chymopapain chemonucleolysis is an alternative to surgery.

Adolescent↗
PubMed1983

Safety and efficacy of chymopapain (Chymodiactin) in herniated nucleus pulposus with sciatica. Results of a randomized, double-blind study.

A double-blind, randomized trial was conducted to compare the efficacy of intradiskal injection of chymopapain (Chymodiactin) with injection of placebo in patients with a herniated lumbar disk. Patients were randomly assigned to either placebo or drug regimens and followed up for six months. The primary measure of performance was agreement by patient and surgeon that further intervention was not necessary. At any time that patient and investigator agreed that treatment had failed, the patient was classified as a failure and the treatment code was broken. Of 53 placebo-treated patients, 31 failed by this criterion. Of 55 drug-treated patients, 15 failed. Placebo-treated patients who failed were allowed to receive drug treatment, and 29 (91%) of 32 were treated successfully. This study demonstrates that chymopapain is more effective than placebo for treatment of patients with a herniated lumbar disk.

Adult↗
PubMed1983

Effects of anticonvulsants and other agents on seizures induced by intracerebral L-glutamate.

Convulsions induced in mice by intracerebral injection of L-glutamate were antagonized by phenytoin, phenobarbital, chlordiazepoxide and valproic acid. Trimethadione had only a small effect at the dose used, and ethosuximide was ineffective. The profile of interaction of glutamate with these antiepileptic agents resembles that of ouabain, and differs considerably from the profiles of other convulsants previously tested. However, muscimol had a small potentiating effect on glutamate but not on ouabain. Neither L-glutamic acid diethyl ester nor L-nuciferine significantly altered the convulsive response to glutamate.

Animals↗
PubMed1982

Interactions of phenytoin with ouabain and other chemical convulsants.

Phenytoin potentiated the convulsive actions of bicuculline and picrotoxin in mice, whereas the action of bemegride was neither potentiated nor antagonized. Seizures induced by intracerebral injection of ouabain were antagonized by phenytoin, as well as by phenobarbital, chlordiazepoxide and valproic acid; trimethadione had a possible small effect, not quite significant at the 5% level; ethosuximide and muscimol did not show significant effects. Seizures induced by intracerebral injection of pentylenetetrazol were antagonized by phenobarbital but not by phenytoin. Tests of phenytoin against other chemical convulsants are reviewed, and it is suggested that phenytoin may be specific for seizures that arise from a derangement of mechanisms involving sodium ions. This strengthens the view that such a derangement is likely in many cases of human epilepsy.

Animals↗
PubMed1981

Muscimol as an antagonist of chemical convulsants.

Muscimol (MU) was tested on mice for anticonvulsive action against chemical convulsants. 3-Mercaptopropionic acid (3-MP) was more sensitive to inhibition by MU (1.5 mg/kg) than was either pentylenetretrazol (PTZ) or bicuculline (BIC); picrotoxin (PIC) and kainic acid were not measurably antagonized; aminophylline was potentiated. The profile of action of MU closely resembles that of aminooxyacetic acid (AOAA), except that the latter strongly antagonizes kainic acid. MU distinguished more clearly than did AOAA between the action of 3-MP and that of either PTZ or BIC, inasmuch as the differences between the respective potency ratios were larger with MU than with AOAA. The results are consistent with the view that MU acts as a GABA agonist, that GABA antagonism is not a sufficient basis on which to explain the convulsive action of BIC or PIC, and that the antagonism of AOAA toward seizures induced by kainic acid may not be due to an action on the GABA system.

Animals↗
PubMed1980

Aminophylline and imidazole as convulsants.

The convulsive actions of aminophylline (APH) and imidazole (IDZ) have been tested against a series of anticonvulsants, and their patterns of sensitivity to these agents are compared with those of other convulsants. APH was antagonized by phenobarbital and chloridiazepoxide, but less effectively than is pentylenetetrazol. Antagonism by trimethadione was not significant. Ethosuximide, phenytoin and aminooxyacetic acid potentiated APH, an effect not seen with other convulsants in our previous studies. IDZ-induced seizures were found to be relative refractory to anticonvulsants, but were antagonized to a small degree by all of those mentioned above except phenytoin; aminooxyacetic acid was relatively the most effective. Phenytoin potentiated IDZ-induced seizures. Subconvulsive doses of APH potentiated pentylenetetrazol- and 3-mercaptopropionic acid-induced seizures about equally, as did IDZ. Possible mechanism of action are discussed.

Aminooxyacetic Acid↗
PubMed1980

Effects of anticonvulsants and glutamate antagonists on the convulsive action of kainic acid.

In its pattern of sensitivity to anticonvulsants, kainic acid (KA) showed little resemblance to pentylenetetrazol (PTZ), 3-mercaptopropionic acid (3-MP), bicuculline, picrotoxin or bemegride. That KA may have an action on the gamma-aminobutyrate system is suggested by the following: it is strongly antagonized by aminooxyacetic acid; ethosuximide is ineffective against KA as it is against 3-MP; and a subconvulsive dose of KA potentiated 3-MP but not PTZ. However, KA is to some extent comparable to PTZ in that it is antagonized by trimethadione, phenobarbital and chlordiazepoxide more effectively than is 3-MP. The convulsive action of KA is potentiated by the glutamate antagonists l-glutamate diethyl ester (GDEE) and l-nuciferine. GDEE also slightly potentiated bicuculline, but not other convulsants tested; it slightly antagonized PTZ. Nuciferine potentiated all except PTZ and bemegride. The failure of these agents to antagonize KA-induced seizures is consistent with the view that KA and glutamate act at separate excitatory receptor sites. The potentiation might possibly be due to a blocking of glutamergic activation of neurons that are inhibitory.

3-Mercaptopropionic Acid↗
PubMed1979

Treatment of increased intracranial pressure: a comparison of different hyperosmotic agents and the use of thiopental.

Long term intracranial pressure (ICP) monitoring was carried out in over 200 patients with various intracranial abnormalities; a fiberoptic epidural intracranial pressure monitor was used. Ninety of these patients had significantly elevated ICP or exhibited pressure waves requiring therapy. Initial therapy consisted of hyperventilation with a respirator and administration of hyperosmotic agents. Comparison studies utilizing 30% urea, 20% mannitol, and furosemide intravenously and 30% urea and 10% glycerol orally were randomly done. In 45 patients two or more of these agents were used at different times in the same patient for comparison of effectiveness. When equimolar amounts of intravenous urea and mannitol were used, similar effects on increased ICP were obtained. There was no significant reduction of increased ICP with the use of furosemide alone. No rebound effect was observed with either mannitol or urea. Orally, urea was more effective than glycerol in equimolar amounts. Again no rebound was observed. In 14 patients who required doses of hyperosmotic agents more frequently than every 4 hours, continuous infusion of thiopental was used in conjunction with the hyperosmotic agents to control pressure. This regimen resulted in good ICP control in 12 patients. A rational protocol for the medical management of increased ICP utilizing hyperosmotic agents and, in refractory cases, hyperosmotic agents plus thiopental has resulted in effective control of ICP in 96% of our patients throughout their course without the need to resort to decompressive surgery. (Neurosurgery, 5: 570--575, 1979).

Brain Diseases↗
PubMed1979

Quantitative evaluation of the actions of anticonvulsants against different chemical convulsants.

Anticonvulsants were tested on mice for their effectiveness against different chemical convulsants. Ethosuximide is very effective against pentylenetetrazol (PTZ), but ineffective against 3-mercaptopropionate (3-MP) which is an inhibitor of gamma-aminobutyrate (GABA) synthesis. Trimethadione, chlordiazepoxide and mesuximide are less effective against 3-MP than against PTZ. The same tendency was apparent, though falling short of statistical significance, with phenobarbital, mephenytoin, carbamazepine and valproic acid, whereas aminooxyacetic acid (AOAA) appeared to be somewhat more effective against 3-MP than against PTZ. Several anticonvulsants were tested also against bicuculline (BIC), picrotoxin (PIC) and bemegride (BEM), and profiles depicting their relative capacities to antagonize the convulsants were constructed. These show major differences and few resemblances. Likewise the convulsants show little resemblance to each other in their patterns of sensitivity to different anticonvulsants. The data do not support the concept that PTZ, BEM, BIC or PIC induce seizures primarily by blockading GABA-mediated inhibition, since their patterns are so unlike that of 3-MP. The profiles of clinically used anticonvulsants suggest that none of those tested acts primarily on the GABA system, since all are so unlike that of AOAA.

Animals↗
PubMed1977

Metrizamide--CSF contrast medium. Analysis of clinical application in 215 patients.

Two-hundred-fifteen patients were evaluated with metrizamide, a new water-soluble contrast agent for use in the subarachnoid spaces. Side effects were reported in 67% of these; 39% were moderate or severe. Cervical injections monitored by fluoroscopy provide the most precise positioning of the medium. The benefits of metrizamide use outweigh its risk.

Cerebrospinal Fluid↗
PubMed1977

Unreliability of epidural venography in lumbar disc disease.

Lumbar epidural venography has been compared with myelography and discography in 69 patients suspected of having nerve root compression from herniated lumbar intervertebral discs. Only 78% agreement occurred when venograms were interpreted as unknowns by two radiologists. Twenty-three percent of the venographic examinations were suboptimal, most of these in patients operated upon previously. False-negative venography occurred in 13%. Midline disc herniations were missed more often than lateral herniations.

Dura Mater↗
PubMedDate not supplied

Treatment of herniated lumbar disk syndrome with chymopapain.

One hundred twenty-four patients with herniated lumbar disks received intradiskal injections of chymopapain before the Food and Drug Administration's withdrawal of the drug. One year after injection, 90 patients (72.6%) experienced major improvement, 21 (16.9%) had slight improvement, and 13 (10.5%) had no improvement. Of those patients who had no previous back surgery and who were not compensation cases, 77 patients (81%) had marked improvement, 13 (13.7%) had slight improvement, and five (5.3%) had no improvement. Three- to six-year follow-ups were obtained by questionnaire. Of the 114 patients responding, overall 83 patients (72.8%) had marked improvement, and 75 (83.3%) of those with no previous surgery and who were not workmen's compensation cases had major improvement. Since all patients met objective criteria for diskectomy, favorable results from chemonucleolysis spared most the trauma of surgery and its attendant convalescence. These results indicate that chemonucleolysis can and should be considered an advantageous alternative to surgery in appropriately selected patients.

Adolescent↗