Search PubMed⌕ Search

Biomedical subjects

E Kanal

Publications and source records attributed to E Kanal.

At least 19 recordsLinked to original sources
PubMed2006

Granulomatous amebic encephalitis in a multivisceral transplant recipient.

A 40-year-old man with multivisceral allograft developed acutely right-sided numbness 9 months after transplantation. Cranial magnetic resonance imaging (MRI) showed a small left parietal lesion, and cerebrospinal fluid analysis was unremarkable. Stereotactic brain biopsy was non-diagnostic. The patient continued to deteriorate, developed cerebral edema and died at 13 days after the onset of symptoms. Unexpectedly, autopsy demonstrated acanthamebic encephalitis. This case highlights diagnostic difficulties encountered with amebic encephalitis and expands the spectrum of opportunistic central nervous system (CNS) infections in solid and visceral organ transplant recipients.

Adult↗
PubMed2004

Safety and biodistribution studies of an HSV multigene vector following intracranial delivery to non-human primates.

Malignant glioma is a fatal human cancer in which surgery, chemo- and radiation therapies are ineffective. Therapeutic gene transfer used in combination with current treatment methods may augment their effectiveness with improved clinical outcome. We have shown that NUREL-C2, a replication-defective multigene HSV-based vector, is effective in treating animal models of glioma. Here, we report safety and biodistribution studies of NUREL-C2 using rhesus macaques as a model host. Increasing total doses (1 x 10(7) to 1 x 10(9) plaque forming units (PFU)) of NUREL-C2 were delivered into the cortex with concomitant delivery of ganciclovir (GCV). The animals were evaluated for changes in behavior, alterations in blood cell counts and chemistry. The results showed that animal behavior was generally unchanged, although the chronic intermediate dose animal became slightly ataxic on day 12 postinjection, a condition resolved by treatment with aspirin. The blood chemistries were unremarkable for all doses. At 4 days following vector injections, magnetic resonance imaging showed inflammatory changes at sites of vector injections concomitant with HSV-TK and TNFalpha expression. The inflammatory response was reduced at 14 days, resolving by 1 month postinjection, a time point when transgene expression also became undetectable. Immunohistochemical staining following animal killing showed the presence of a diffuse low-grade gliosis with infiltrating macrophages localized to the injection site, which also resolved by 1 month postinoculation. Viral antigens were not detected and injected animals did not develop HSV-neutralizing antibodies. Biodistribution studies revealed that vector genomes remained at the site of injection and were not detected in other tissues including contralateral brain. We concluded that intracranial delivery of 1 x 10(9) PFU NUREL-C2, the highest anticipated patient dose, was well tolerated and should be suitable for safety testing in humans.

Animals↗
PubMed2001

A clinical comparison of the safety and efficacy of MultiHance (gadobenate dimeglumine) and Omniscan (Gadodiamide) in magnetic resonance imaging in patients with central nervous system pathology.

RATIONALE AND OBJECTIVES: The safety and diagnostic efficacy of MultiHance (gadobenate dimeglumine) in the central nervous system (CNS) were evaluated in a double-blind, multicenter, phase III clinical trial. METHODS: Two hundred five patients highly suspected of having a CNS lesion (by previous imaging exam) were enrolled at 16 sites in the United States. Patients were randomized to one of three incremental dosing regimens. Magnetic resonance imaging with Omniscan (gadodiamide) at doses of 0.1 and 0.3 mmol/kg was compared with MultiHance (gadobenate dimeglumine) at doses of 0.05 and 0.15 mmol/kg and at 0.1 and 0.2 mmol/kg. RESULTS: Compared with predose images alone, efficacy was demonstrated in each of the gadobenate dimeglumine and gadodiamide groups (single and cumulative doses) as indicated by the level of diagnostic information, number of lesions detected, and contrast-to-noise ratio measurements. The level of diagnostic information from gadobenate dimeglumine at 0.1 mmol/kg was equivalent to that with gadodiamide at the same dose. One of the two blinded reviewers found equivalence between the gadobenate dimeglumine 0.05 mmol/kg dose and gadodiamide at 0.1 mmol/kg. Both reviewers found the level of diagnostic information to be equivalent after the second dose of contrast for all three dosing regimens. The cumulative doses of gadobenate dimeglumine were well tolerated and as safe as gadodiamide. CONCLUSIONS: Gadobenate dimeglumine is comparable to gadodiamide in terms of safety and efficacy for imaging of CNS lesions, with a possible advantage in imaging applications owing to enhanced T1 relaxivity.

Brain Neoplasms↗
PubMed2001

Imaging the trigeminal nerve and pons before and after surgical intervention for trigeminal neuralgia.

OBJECTIVE: To study the various imaging changes occurring in the trigeminal nerve and brainstem in patients before or after trigeminal neuralgia surgery. METHODS: During a 7-year period, 275 patients with trigeminal neuralgia underwent high-resolution, contrast-enhanced magnetic resonance imaging (MRI) of the pons during gamma knife radiosurgery. Ninety-seven patients had no previous surgical intervention for trigeminal neuralgia, and 178 patients had undergone one or more previous procedures. Two independent observers, one of whom was blinded to patients' clinical details, reviewed MRI scans retrospectively. The analysis of the independent observers was then correlated with all previous therapeutic interventions. RESULTS: One hundred one MRI scans demonstrated no radiological changes related to trigeminal neuralgia, and 174 MRI scans exhibited some radiological abnormality. The average axial plane diameter of the nerve for all patients was 4 mm (range, 2-6 mm). In the group that had not undergone previous surgery, 65 patients (67%) exhibited vascular compression. In the 88 patients who had undergone previous microvascular decompression, 21 (24%) had evidence of a pontine infarction. Twenty-six patients experienced facial sensory loss, 22 (88%) of whom had undergone previous surgery with evidence of a pontine infarction (n = 11) or perineural scarring (n = 6). CONCLUSION: The majority of patients who had undergone previous trigeminal neuralgia surgery demonstrated readily identifiable abnormalities of the trigeminal nerve or brainstem. The frequency of such changes correlated with the type and number of procedures. Evidence of vascular compression was detected in the majority of patients. Most patients with postoperative facial sensory loss demonstrate changes in the nerve or pons on MR images.

Adult↗
PubMed2001

Infectious aneurysm clipping by an MRI/MRA wand-guided protocol. A case report and technical note.

Infectious aneurysms are potentially deadly sequelae of multiple etiologies, typically associated with subacute bacterial endocarditis (SBE). Since these aneurysms tend to be distal, there are no consistent landmarks by which to localize them, in contrast to more typical aneurysms that occur on the circle of Willis or proximal, large cerebral vessel bifurcations. In addition, they tend to be extremely friable and may be obscured by blood if intracranial hemorrhage (ICH) has already occurred. These factors make clipping these aneurysms technically difficult, and searching for easily ruptured aneurysms without standard landmarks adds risk to the procedure. In this report, we describe the case of a 9-year-old boy with SBE and subsequent ICH secondary to a mycotic aneurysm. This aneurysm was localized to within millimeters by the MRI protocol described herein. The aneurysm was excised and the patient recovered without incident. Thus, MRI/MRA-guided frameless stereotaxy may be useful for localizing distal mycotic aneurysms, improving patient outcome by decreasing morbidity and mortality.

Aneurysm, Infected↗
PubMed2001

Vertebral mass resulting from a chronic-contained rupture of an abdominal aortic aneurysm repair graft.

We describe a case of a 63-year-old man with chronic-contained rupture of an abdominal aortic aneurysm at the site of prior graft repair of the aneurysm. Initially misinterpreted as osteomyelitis on the basis of CT findings, this chronic-contained rupture of the abdominal aorta eroding the vertebrae was preoperatively diagnosed at MR imaging and confirmed at surgery. A conventional angiogram failed to show the pseudoaneurysm. Owing to a major difference in the management of a contained aortic aneurysm rupture versus that for osteomyelitis, MR imaging with CT or MR angiography is recommended before any operative or invasive procedure.

Aortic Aneurysm, Abdominal↗
PubMed2000

Conversion to neoral for neurotoxicity after primary adult liver transplantation under tacrolimus.

BACKGROUND: Neurological complications after orthotopic liver transplantation (OLTX) have remained a major concern in a small proportion of patients. The etiology of these complications is often thought to be multifactorial: the influence of calcineurin inhibitors is occasionally thought to play an important role. When neurotoxicity occurs after OLTX under tacrolimus, it is usually a minor complication and responds readily to a reduction in the dosage of or a temporary withdrawal of tacrolimus. However, neurotoxic complications occasionally do not respond to this conventional process. Neoral is a microemulsion formulation of cyclosporine. It has more consistent pharmacokinetic parameters and improved bioavailability when compared with conventional cyclosporine. The aim of the present report was to evaluate the role of Neoral in OLTX recipients with neurotoxic complication who failed to respond to a reduction in the dosage of tacrolimus. METHOD: Between August 1995 and November 1997, 330 adults (age >18 years) received primary OLTX under tacrolimus-based immunosuppression (mean age 52.6+/-11.4 years). There were 190 men and 140 women. Twenty-three (7%) patients (mean age 53.2+/-11.8 years; 17 men, 6 women) were converted to Neoral (mean 35+/-41 days after OLTX). These patients were followed until June 1998 (mean follow-up 22.7+/-7.8 months). RESULTS: Four (17.4%) patients died during the follow-up period, and two patients underwent retransplantation. Neurological symptoms improved in all patients who survived. Adequate trough concentrations were achieved in all patients with p.o. Neoral. Nine (39%) patients experienced rejection episodes after conversion. Six (26.1%) patients were converted back to tacrolimus because of ongoing rejection (n=3), retransplantation (n=2), or persistent nausea and vomiting (n=1) without recurrence of the original neurological complication. CONCLUSION: Neurological complications after OLTX disorders that occur under tacrolimus and that fail to respond to a reduction in the dosage can be treated safely by conversion to Neoral. However, the rate of rejection is up to 39%, and patients can often be converted back to tacrolimus without recurrence of the original neurological complication.

Adult↗
PubMed2000

Implantable pulse generators (pacemakers) and electrodes: safety in the magnetic resonance imaging scanner environment.

Static magnetic fields, time-varying electric and magnetic fields, and electromagnetic interference within the magnetic resonance imaging scanner environment can cause the implantable pulse generator (pacemaker) to malfunction and render the electrodes hazardous to the patient. This article provides a review of the literature and of international regulatory guidance concerning safety considerations when these implantable devices are exposed to magnetic resonance imaging.

Electrodes↗
PubMed2000

Magnetic resonance imaging in patients with central nervous system pathology: a comparison of OptiMARK (Gd-DTPA-BMEA) and Magnevist (Gd-DTPA).

RATIONALE AND OBJECTIVES: The objective of the two pivotal phase 3 studies was to evaluate the safety and efficacy of OptiMARK (Gd-DTPA-bis(methoxyethylamide) [Gd-DTPA-BMEA]) compared with Magnevist (Gd-DTPA) in magnetic resonance imaging of the central nervous system. METHODS: Two multicenter, randomized, double-blind, parallel group studies were conducted in 395 patients with known or suspected central nervous system pathology. Subjects were randomized to receive a single 0.1 mmol/kg intravenous injection of either Gd-DTPA-BMEA or Gd-DTPA. The safety of Gd-DTPA-BMEA and Gd-DTPA was monitored for up to 72 hours after study drug administration. Precontrast and postcontrast administration magnetic resonance scans were acquired using identical imaging planes and techniques. RESULTS: No deaths or unexpected adverse events were reported in either group. A comparison of adverse events by intensity and relation demonstrated no statistically significant differences between the two groups. Gd-DTPA-BMEA and Gd-DTPA were equivalent with respect to confidence in diagnosis, conspicuity, and border delineation. CONCLUSIONS: Gd-DTPA-BMEA and Gd-DTPA demonstrated comparable efficacy profiles, and the safety profiles were considered similar.

Adult↗
PubMed1999

Safety of magnetic resonance imaging contrast agents.

Many of the MR examinations performed in the world each year are accompanied by administration of one of these frequently used intravenous contrast agents: Magnevist, Omniscan, and ProHance. Accordingly, MR practitioners must understand the basic pharmacokinetics, side effects, and the potential for adverse events for these contrast agents. Additionally, MR practitioners must know how to manage side effects and adverse events that may occur in association with the administration of contrast agents. Notably, the use of MR imaging contrast agents in special patient populations must be understood. This article discusses each of these important issues.

Animals↗
PubMed1999

Development of obstructive hydrocephalus with lumboperitoneal shunting following subarachnoid hemorrhage.

Hydrocephalus is a frequent complication of subarachnoid hemorrhage (SAH). The optimum method of treating hydrocephalus in this setting has not been determined. We review our experience with patients developing communicating hydrocephalus secondary to SAH and subsequently treated with lumboperitoneal (LP) shunts. Following hospitalization for the treatment of SAH, patients who developed clinical symptoms and radiologic signs of hydrocephalus were treated with (ventriculoperitoneal) VP or LP shunting. Eighteen patients received an LP shunt, of which seven (28%) developed a non-communicating or obstructive hydrocephalus. These seven patients underwent replacement with a VP shunt and have not had further complications. In the setting of post-SAH communicating hydrocephalus, obstructive hydrocephalus may develop after LP shunt placement. Patients who develop this complication and have their LP shunts converted to VP shunts have a favorable prognosis.

Adult↗
PubMed1999

Aneurysm clips: effects of long-term and multiple exposures to a 1.5-T MR system.

The authors evaluated the ferromagnetic properties of multiple nonferromagnetic aneurysm clips before and after long-term and multiple exposures to a 1.5-T magnetic resonance system. No alterations in the magnetic properties of these clips was observed. These findings suggest that repeated or chronic exposure of patients with implanted nonferromagnetic aneurysm clips to strong static magnetic fields is unlikely to result in any clinically significant alteration in the magnetic properties of these clips.

Contraindications↗
PubMed1999

MR imaging of intraventricular silicone: case report.

A 42-year-old man with human immunodeficiency viral infection developed cytomegaloviral retinitis that was complicated by retinal detachment and was treated with an intravitreous injection of silicone. Fifteen months later, magnetic resonance imaging revealed intraocular and intraventricular silicone. Signal intensity characteristics and chemical shifts of silicone in the two locations were identical.

AIDS-Related Opportunistic Infections↗
PubMed1999

Iatrogenic pneumocephalus secondary to intravenous catheterization. Case report.

The presence of pneumocephalus in a patient without a history of undergoing intracranial or intrathecal procedures is a significant radiographic finding that portends a violation of the dural barrier or the presence of infection. The authors report a case of iatrogenic pneumocephalus that confounded the evaluation of a patient with unrelated neurological disorders, resulting in unnecessary transfer of the patient and utilization of medical resources. A review of 100 sequential computerized tomography scans obtained in patients for any indication in the emergency department revealed a 6% incidence of iatrogenic intravenous pneumocephalus. Computerized tomography scans revealing pneumocephalus had been obtained for altered mental status, focal motor deficit, seizure, and trauma. More careful intravenous catheterization and recognition of the condition on imaging may avoid similar problems.

Catheterization, Peripheral↗