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Biomedical subjects

M R Patel

Publications and source records attributed to M R Patel.

At least 37 records · Page 2Linked to original sources
PubMed1998

Inhibitory effect of chlorpromazine on nematode eggs and larvae.

Chlorpromazine inhibited the hatching of eggs of the parasitic nematode Haemonchus contortus and the free-living nematode Caenorhabditis elegans. In both species, hatching occurred at a concentration of 100 microg/ml but was almost totally blocked at 400 microg/ml. In the case of C. elegans, the effect was shown to be reversible by removal of chlorpromazine after exposure of the eggs to the drug for 1 hr. Caenorhabditis elegans larvae that hatched in a chlorpromazine concentration of 100 microg/ml were killed, but those that hatched in a concentration of 6.25 microg/ml were not. Taken together with data published by others, these observations indicate that the first-stage larva of C. elegans is less sensitive to chlorpromazine than is the adult worm.

Animals↗
PubMed1997

Percutaneous release of trigger digit with and without cortisone injection.

Percutaneous release was done using the tip of an 18-gauge, 2.5-cm-long needle, mounted on a 3-mL3 syringe in 225 trigger digits. It was successful in 92 (89%) of the digits without cortisone injection (n = 105) and in 115 (96%) of the digits with cortisone injection (n = 120). Negligible or intermittent pain persisted for 8 weeks in the noncortisone group and 6 weeks in the cortisone group after percutaneous release. Of the first 10 digits, 2 needed repeat percutaneous release. With modification of technique, the incidence of repeat percutaneous release was zero in both groups. Open release was needed in 8% in the noncortisone group and 3% in the cortisone group. The procedure was done under local infiltration anesthesia in the office. This reduced patient anxiety, inconvenience and hospital cost.

Adult↗
PubMed1997

Percutaneous fibrin glue therapy of meningeal cysts of the sacral spine.

OBJECTIVE: We assessed CT-guided percutaneous injection of fibrin glue to manage meningeal cysts of the sacral spine in patients with back pain. CONCLUSION: All patients experienced resolution or marked improvement of symptoms for as long as 23 months after fibrin glue therapy. No patients experienced recurrence of symptoms during the follow-up interval. Percutaneous CT-guided fibrin glue therapy for sacral meningeal cysts may be a more definitive therapy than repetitive cyst aspiration.

Adult↗
PubMed1997

Intraneural mucous cysts of peripheral nerves.

We present three cases of a rare mucous cyst inside the peripheral nerves of the upper extremity; a lateral cutaneous nerve of the forearm, a dorsal sensory branch of the ulnar nerve, and a median nerve at the wrist. All our cases were intraneural, and we excised longitudinal strips of the cyst wall between nerve fascicles in all, preserving nerve function in each case.

Adult↗
PubMed1997

Half-fourier acquisition single-shot turbo spin-echo (HASTE) MR: comparison with fast spin-echo MR in diseases of the brain.

PURPOSE: To compare an ultrafast T2-weighted (half-Fourier acquisition single-shot turbo spin-echo [HASTE]) pulse sequence with fast spin-echo T2-weighted sequences in MR imaging of brain lesions. METHODS: Fast spin-echo and HASTE images of 34 consecutive patients over the age of 50 years or with suspected demyelinating disease were reviewed independently by two neuroradiologists for the number of lesions less than 5 mm and greater than or equal to 5 mm, and for lesion conspicuity, gray-white matter differentiation, and extent of periventricular confluent signal abnormality. The reviewers also assessed for the presence of hemosiderin and extent of motion artifacts. RESULTS: Per patient, the mean number of 5-mm or larger lesions detected on fast spin-echo images (1.4) relative to the number detected on HASTE images (0.8) was not statistically significant. For lesions less than 5 mm, fast spin-echo images showed more lesions (7.5) than HASTE images did (2.4). The fast spin-echo images were better at depicting gray-white matter differentiation, conspicuity of lesions, and periventricular signal abnormality. Of four T2 hypointense lesions seen on fast spin-echo images, none was detected on HASTE images. CONCLUSION: Although the HASTE technique might be useful for rapid imaging of the brain, our study shows a diminished sensitivity for the detection of lesions less than 5 mm in diameter and for T2 hypointense lesions.

Adult↗
PubMed1997

Enhanced ability of third-stage larvae of Haemonchus contortus to withstand drug exposure following chemically induced exsheathment.

Normal (ensheathed) and exsheathed third-stage larvae of Haemonchus contortus were exposed in vitro to various concentrations of levamisole or ivermectin. Exsheathment was induced by brief exposure to sodium hypochlorite. When observed approximately 2 min after immersion in levamisole at 0, 5, 10, and 100 micrograms/ml (3 trials), the mean percentage motility (to nearest whole number) of normal larvae was 84, 43, 37, and 15, respectively. However, the mean percent motility of exsheathed larvae was 77, 78, 79, and 72, respectively. When observed 55 min after immersion in levamisole at the same concentrations, the mean percent motility of normal larvae was 76, 4, 3, and 0, respectively, whereas that for exsheathed larvae was 72, 75, 68, and 0. When observed 45 min after initial exposure to ivermectin at 0, 8, 80, and 160 micrograms/ml, the mean percent motility of normal larvae was 87, 6, 3, and 3, respectively, whereas the mean percent motility of exsheathed larvae was 94, 75, 29, and 14, respectively. Thus, both drugs were effective against both kinds of larva; but the time and concentration required for efficacy were markedly affected by the presence or absence of a sheath or by unknown effects of the exsheathment process. For both levamisole and ivermectin, exsheathed larvae had a much greater ability than normal larvae to withstand drug exposure.

Animals↗
PubMed1996

M6P/IGF2 receptor: a candidate breast tumor suppressor gene.

The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2r) functions in the activation of TGFbeta, a potent growth inhibitor for most cell types, the degradation of the mitogen, IGF2, and the intracellular trafficking of lysosomal enzymes. We have found its expression to be significantly reduced in both rat and human hepatocellular carcinomas (HCCs) and recently reported loss of heterozygosity (LOH) at this locus with mutations in the remaining allele in human liver tumors. Using the polymerase chain reaction, we utilized two polymorphisms in the 3' untranslated region of M6P/IGF2r to screen breast tumors for LOH. Forty of 62 (65%) patients were informative (heterozygous) and 12/40 (30%) breast tumors had LOH; 5/19 (26%) carcinomas in situ (CIS) and 7/21 (33%) invasive carcinomas. To investigate the early molecular genetic events in breast carcinogenesis, we screened the CIS with LOH for mutations. In 2/5 (40%) of these tumors, missense mutations were found in the remaining allele that gave rise to significant amino acid substitutions. These findings provide evidence that M6P/IGF2r allelic loss is an early event in the etiology of breast cancer, that this gene functions as a tumor suppressor gene in the breast.

Amino Acid Sequence↗
PubMed1996

Multiple schwannomas of the ulnar nerve: a case report.

Multiple schwannomas may occur as visible tumors or may occur as tumors in situ. The tumors in situ may be missed when the visible tumors are excised. In time, the schwannomas in situ grow and appear to be recurrent, while in fact, they are multicentric. The prognosis on multicentric schwannomas thus remains guarded.

Adult↗
PubMed1996

Detection of hyperacute primary intraparenchymal hemorrhage by magnetic resonance imaging.

BACKGROUND: MRI has become increasingly used in the acute setting to manage patients with stroke. There has been concern that MRI may not be sensitive in the detection of acute intracranial hemorrhage. We assessed whether strongly susceptibility-weighted MRI would be sensitive to intraparenchymal hemorrhage in the first few hours. CASE DESCRIPTIONS: In the course of our ongoing studies of MRI of acute ischemic stroke in more than 200 patients, 35 patients had MR studies within 6 hours. Six of these patients who presented with acute focal symptoms with definite time of clinical onset (2.5 to 5 hours) were found to have evidence of intraparenchymal hemorrhage. Standard T1- and T2-weighted MR scans were performed. In 5 of the patients, echo-planar imaging and gradient-echo sequences were performed to increase the sensitivity of magnetic susceptibility effects of the pulse sequences. Four of the cases were of putaminal hemorrhage and 2 were lobar hemorrhages. The hemorrhage was most evident as foci of T2* hypointensity (signal loss) and unambiguous on the more susceptibility-weighted sequences, particularly echo-planar gradient-echo images. CONCLUSIONS: MRI can detect hemorrhage within 2.5 to 5 hours of onset of clinical symptoms as regions of marked signal loss due to susceptibility effects, whereas conventional MR scans of ischemic stroke may appear normal. These results demonstrate that MR susceptibility sequences may be sensitive to hyperacute hemorrhage and suggest that MR may be an adequate screen for primary intraparenchymal hemorrhage.

Acute Disease↗
PubMed1996

EEG-triggered echo-planar functional MRI in epilepsy.

We investigated whether: (1) EEG recordings could be successfully performed in an MRI imager, (2) subclinical epileptic discharges could be used to trigger ultrafast functional MRI images, (3) artifact-free functional MRI images could be obtained while the patient was having the EEG monitored, and (4) the functional MRI images so obtained would show focal signal increases in relation to epileptic discharges. We report our results in two patients who showed focally higher signal intensity, reflective of increased local blood flow, in ultrafast functional MRI timed to epileptic discharges recorded while the patients were in the imager and compared with images not associated with discharges. One patient showed a focal increase despite a clinical and EEG history of generalized discharges. This approach may have the potential to identify brain regions activated during brief focal epileptic discharges.

Adult↗
PubMed1996

Unusual manifestations of head trauma.

Head injury is the leading cause of death in young adults. More than 2 million head injuries occur each year in the United States. Accurate and rapid diagnosis is imperative for the successful management of the trauma patient. The radiologic findings of common manifestations of head trauma have been well described; however, the patient who presents in the post-traumatic period with atypical radiographic findings is at risk for misdiagnosis and delay in treatment. In this essay, we illustrate some unusual findings in head injury that may complicate diagnosis.

Adolescent↗
PubMed1996

Intraepineurial constriction of nerve fascicles in pronator syndrome and anterior interosseous nerve syndrome.

In PS or AINS, if obvious epineurial compression deformity of the median nerve or the AIN is not found at known sites of compression, IeCNF should be considered. IeCNF may occur in one or more nerve fascicles of the median nerve at one of multiple levels in the distal upper arm and proximal forearm. Decompression of the nerve fascicles is achieved by epineurotomy, microsurgical interfascicular dissection, and removal of the constricting outer layer of the perineurium above and below the elbow. Resection of the constricted segments of the nerve fascicles is not necessary. Intraepineurial exploration of the nerve trunk also may be considered if, after surgical decompression of PS and AINS, expected recovery has not occurred and there is no evidence of axonal degeneration.

Diagnosis, Differential↗
PubMed1996

Postoperative cerebrospinal fluid leaks of the lumbosacral spine: management with percutaneous fibrin glue.

PURPOSE: To assess CT-guided injection of fibrin glue for the management of lumbosacral cerebrospinal fluid (CSF) leaks. METHODS: Six consecutive patients with postoperative CSF leaks were treated after CSF aspiration under CT guidance. A solution of cryoprecipitate was simultaneously injected with a 10% calcium chloride solution containing 2000 units of thrombin per milliliter. In one patient, 0.5 mL of iopamidol was added to the calcium chloride/thrombin mixture before injection. Placement of the fibrin glue aggregate was confirmed by CT imaging. To determine outcomes we reviewed the patients' records, postprocedure imaging studies, and physical findings, and we interviewed the patients directly. RESULTS: In three patients with postoperative CSF leaks, symptoms resolved after treatment. Despite imaging evidence of successful plug deployment, two other patients still had severe symptoms, and they underwent surgery after 2 and 18 hours, respectively. One patient had a continued CSF leak and a headache after 12 hours; follow-up surgery repaired an unsuspected dural tear just distal to the site of original surgery underneath the lamina and not covered by the fibrin glue. After one of the successful procedures, the patient had a fever and a headache, probably because of aseptic meningitis, which resolved after 2 days. CONCLUSION: Percutaneous CT-guided placement of fibrin glue may provide nonsurgical treatment for postoperative CSF leaks, potentially avoiding a major and technically difficult surgical procedure.

Administration, Cutaneous↗
PubMed1996

MR angiography of the head and neck.

A review of the basic physics and techniques for acquiring and evaluating magnetic resonance angiograms is provided, including time-of-flight and phase contrast techniques. Magnetic resonance (MR) angiography is becoming a routine method of evaluating carotid bifurcation atherosclerotic disease in both a screening and diagnostic capacity. The expanding clinical utility of MR angiography in the detection of intracranial aneurysms, characterization of arteriovenous malformations, and evaluation of intracranial atherosclerotic disease are also reviewed. Furthermore, MR angiography allows for the noninvasive diagnosis of arterial dissection. Magnetic resonance venography also allows the confirmation of the previously elusive and likely underdiagnosed entity of cerebral venous thrombosis.

Carotid Artery Diseases↗
PubMed1995

Perioperative imaging strategies for carotid endarterectomy. An analysis of morbidity and cost-effectiveness in symptomatic patients.

OBJECTIVE: To assess the cost-effectiveness of four diagnostic strategies for the preoperative evaluation of symptomatic patients who are potential candidates for carotid endarterectomy (ie, 70% to 99% stenosis): (1) duplex sonography (DS), (2) magnetic resonance angiography (MRA), (3) contrast angiography (CA), and (4) the combination of DS and MRA supplemented by CA for disparate results. METHODS: Cost-effectiveness analysis based largely on published clinical trial data. Sensitivities and specificities of noninvasive tests were estimated from 81 patients undergoing prospective evaluation with DS, MRA, and CA. OUTCOME MEASURE: Incremental cost per quality-adjusted year of life gained. RESULTS: For a hypothetical cohort of symptomatic patients undergoing evaluation for carotid endarterectomy, the combination of tests resulted in the greatest quality-adjusted life expectancy of the four options considered. After incorporating the costs of testing, surgery, and stroke, we found that neither the MRA nor the CA strategy was cost-effective. The combination of tests was more effective but more costly than DS, resulting in an additional cost of $22,400 per quality-adjusted year of life gained. For centers that do not have adequate MRA, CA resulted in an additional cost of $99,200 per quality-adjusted year of life saved compared with DS. CONCLUSIONS: Our results suggest that for the preoperative detection of a 70% to 99% carotid stenosis, the combination of DS and MRA, supplemented by CA for disparate results, is associated with the lowest long-term morbidity and mortality and has a favorable cost-effectiveness ratio. The combination of tests, or DS alone when MRA is not available, could potentially replace the current practice of using CA alone in the preoperative evaluation of patients with symptomatic carotid stenosis.

Aged↗