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Biomedical subjects

I S Ciric

Publications and source records attributed to I S Ciric.

At least 19 recordsLinked to original sources

Interstitial chemotherapy with drug polymer implants for the treatment of recurrent gliomas.

Malignant gliomas have been difficult to treat with chemotherapy. The most effective agent, BCNU (carmustine), has considerable systemic toxicity and a short half-life in serum. To obviate these problems, a method has been developed for the local sustained release of chemotherapeutic agents by their incorporation into biodegradable polymers. Implantation of the drug-impregnated polymer at the tumor site allows prolonged local exposure with minimal systemic exposure. In this Phase I-II study, 21 patients with recurrent malignant glioma were treated with BCNU released interstitially by means of a polyanhydride biodegradable polymer implant. Up to eight polymer wafers were placed in the resection cavity intraoperatively, upon completion of tumor debulking. The polymer releases the therapeutic drug for approximately 3 weeks. Three increasing concentrations of BCNU were studied; the treatment was well tolerated at all three levels. There were no adverse reactions to the BCNU wafer treatment itself. The average survival period after reoperation was 65 weeks for the first dose group, 64 weeks for the second dose group, and 32 weeks for the highest dose group. The overall mean survival time was 48 weeks from reoperation and 94 weeks from the original operation. The overall median survival times were 46 weeks postimplant and 87 weeks from initial surgery. Eighteen (86%) of 21 patients lived more than 1 year from the time of their initial diagnosis and eight (38%) of 21 patients lived more than 1 year after intracranial implantation of the polymer. Frequent hematology, blood chemistry, and urinalysis tests did not reveal any systemic effect from this interstitial chemotherapy. Since the therapy is well tolerated and safe, a placebo-controlled clinical trial has been started. The trial will measure the effect of the second treatment dose on survival of patients with recurrent malignant glioma.

Brain Neoplasms

Reoperation for malignant astrocytoma.

We evaluated 15 consecutive patients with malignant astrocytomas who were reoperated for functional status and survival. Their Karnovsky Performance Status (KPS) was not changed by surgery. None suffered perioperative death, wound infection, or complications. Patients with glioblastoma maintained KPS unchanged for a mean of 13 weeks (median, 10 weeks); with anaplastic astrocytoma, mean, 37.2 weeks (median, 24 weeks). Life spans were approximately twice that of non-reoperated historical controls. Reoperation for patients with recurrent malignant astrocytoma should be seriously considered when a gross total re-resection can be the goal in a patient whose tumor is in an accessible brain region.

Adult

Current concepts in neuroradiological diagnosis of acoustic neuromas.

Two hundred twenty-one cases with clinical suspicion of a cerebellopontine angle (CPA) and/or internal auditory canal (IAC) lesions were evaluated in our hospital in the last 21/2 years by various radiological modalities. Fifty-two tumors were diagnosed and surgically removed; 48 were acoustic neuromas (33 large tumors and 15 intracanalicular small tumors) and 4 meningiomas. Polytomography detected 10 lesions out of 15 (66.7%) with 5 false-negative (33.3%) and 4 false-positive (26.7%) studies. Routine CT scan visualized large and enhancing lesions (37 out of 52), but missed the small intracanalicular tumors (15 tumors) which were only visualized by CT scan combined with cisternography or magnetic resonance imaging (MRI). MRI diagnosed 23 lesions out of 23 (100%) with no false-positive or negative studies, including 8 intracanalicular small tumors missed on the routine CT scans. MRI is far more reliable in the radiological diagnosis of CPA and IAC lesions.

Cerebellar Neoplasms

Milliwatt carbon dioxide laser and hepatic surgery in mice: surgical technique and pathology.

The milliwatt carbon dioxide laser was used to induce focal lesions and to perform wedge resections in the livers of 75 strain A mice. The procedures were feasible and well tolerated by the mice, with only one postoperative death in the wedge resection group in an early experiment. The hepatic lesions produced by the laser were characterized histologically by an inner area of vaporization, an intermediate area of coagulation necrosis, and an outer rim of cells with variable damage. The lesions healed by fibroblastic proliferation and scar formation with no hepatocytic contribution. The small vessel and bile ductule sealing effect of CO2 laser, together with the sound healing of laser-induced wounds, highlights the usefulness of this modality in liver surgery in general, and suggests its particular application in the treatment of liver trauma and a variety of hepatic focal lesions, neoplastic or otherwise.

Animals

Vascular malformations of the thalamus with normal angiograms.

We describe two patients with fatal vascular malformations of the thalamus whom we thought had gliomas. They had progressive neurological impairment with subacute onset as adults. Computed tomography showed lesions of increased density with slight post-contrast enhancement; cerebral angiography was normal. Without biopsy, they received radiation therapy without benefit. Two other patients with similar radiological studies have done well with conservative treatment. We believe that these lesions have a distinctive appearance on CT, that vascular malformations can be diagnosed, even with normal cerebral angiograms, and distinguished with reasonable certainty from gliomas.

Adult

[Transsphenoidal Microneurosurgery. Part 4: Neuroophthalmological cure in pituitary adenoma].

Fifty-nine pituitary adenomas treated with transsphenoidal approach were analyzed in the light of visual field defects and the postoperative cure rates. Twenty-six cases had visual field defects. The majority of the defects were temporal 1/2 or superior 1/4, although atypical deficits such as incongruous homonymous hemianopsia, nasal 1/2 defect, superior 1/2 defect, peripheral constrict were seen. The visual field defects were correlated with the size of the tumor in Hardy and Vezina classification of the suprasellar extension. The visual field defects appeared in 100% of Type C, 89% of Type B, 50% of Type A, 0% of Type O. In 24 out of 26 patients with preoperative visual field defect, the visual field improved either to normal or wider fields postoperatively. There were 9 patients with optic atrophy, which also showed the correlation with the tumor size. Only the tumor of Type B or C revealed optic atrophy but still 45.4% patients in this group had no optic atrophy. The visual field defect in 85% of the patients without optic atrophy improved to normal post-operatively, while 66% with mild and only 20% with severe optic atrophy showed complete recovery. In conclusions, authors emphasize followings. 1) Improvement rate in the visual field defect of pituitary adenomas by transsphenoidal approach was superior to the previously reported rates by transcranial operations. 2) The factors affecting the functional prognosis in the visual field defect are the natures of the tumor, surgical approach and the factors affecting the plasticity of the optic nerves. The existence and degree of optic atrophy could be one of the references for the plasticity of the optic nerves. 3) There is a close relation between the morphological potential of the tumor and optic atrophy/visual field defect. From these standpoints of view, the early diagnosis and treatment should be emphasized.

Adenoma

Recognition of lumbar disc disease with magnetic resonance imaging.

Ten normal adult volunteers, 75 patients with low back pain and/or lumbar radiculopathy, 16 patients following chymopapain treatment, 14 patients with recurrent symptoms following disc surgery, and two patients with distal cord compression were scanned on Fonar 3000 permanent magnet scanner. Of all the patients 98 had additional computed tomography scans (CT) of the lumbar spine and 82 had myelography. Lumbar magnetic resonance imaging (MRI) and CT scans were both diagnostic in cases of herniated and extruded discs. MRI scan showed more information concerning the degenerative state of the intervertebral discs. It was relatively more accurate in detecting, small bulging and herniated discs without ruptured anulus and the relation of the migrated fragments of extruded discs to both the back of the vertebrae and the thecal sac. Moreover, lumbar MRI matched the clinical response of disc disease to chymopapain treatment more than lumbar CT scan. In addition, the MRI studies differentiated more accurately postoperative epidural fibrotic changes from recurrent herniated and/or extruded disc and detected distal spinal cord abnormalities. CT scan easily detected laterally herniated lumbar discs. Myelography was the diagnostic study in cases of arachnoiditis.

Adult

MR imaging in spinal echinococcosis.

A case of spinal echinococcosis with dorsal spinal cord compression is presented and the findings on plain radiography, polytomography, myelography, CT, and magnetic resonance (MR) imaging are discussed. Although CT and MR are complementary studies for the diagnosis of spinal echinococcosis, MR is the study of choice for prolonged follow-up of complicated cases.

Adult