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Biomedical subjects

L Junck

Publications and source records attributed to L Junck.

At least 37 records · Page 2Linked to original sources
PubMed1996

Decreased striatal monoaminergic terminals in olivopontocerebellar atrophy and multiple system atrophy demonstrated with positron emission tomography.

We used [11C]dihydrotetrabenazine, a new ligand for the type 2 vesicular monoamine transporter (VMAT2), with positron emission tomography to study striatal monoaminergic presynaptic terminals in 4 patients with multiple system atrophy, 8 with sporadic olivopontocerebellar atrophy, and 9 normal control subjects. Specific binding in the striatum was significantly reduced in the multiple system atrophy patients as compared with the normal control group, with average reductions of 61% in the caudate nucleus (p = 0.002) and 58% in the putamen (p = 0.009). Smaller reductions were found in the sporadic olivopontocerebellar atrophy group, averaging 26% in the caudate nucleus (p = 0.05) and 24% in the putamen (p = 0.11). Mean blood-to-brain [11C]dihydrotetrabenazine transport (K1) was significantly different between groups only in the cerebellum, with values for the sporadic olivopontocerebellar atrophy group diminished compared with the normal control group. Cerebellar K1 was not significantly decreased in the multiple system atrophy group. The finding of reduced striatal VMAT2 in sporadic olivopontocerebellar atrophy patients suggests nigrostriatal pathology, indicating that some may later develop symptomatic extrapyramidal disease.

Adult↗
PubMed1996

Effects of disulfiram on positron emission tomography and neuropsychological studies in severe chronic alcoholism.

Disulfiram is an aldehyde dehydrogenase inhibitor that is widely used as an adjunctive agent in the treatment of patients with severe chronic alcoholism. Recent positron emission tomography (PET) studies of local cerebral metabolic rates for glucose (ICMRglc) and benzodiazepine receptor binding in alcoholic patients have shown regional cerebral abnormalities; however, some of the patients were studied while receiving disulfiram, which could influence the biochemical processes under investigation. In a retrospective investigation, we examined the influence of disulfiram administration on the results of PET studies of ICMRglc and benzodiazepine receptor binding and neuropsychological tests of cognition and executive function in patients with severe chronic alcoholism. [18F]Fluorodeoxyglucose was used to measure ICMRglc in 48 male patients, including 11 receiving and 37 not receiving disulfiram in therapeutic doses. [11C]Flumazenil was used to measure benzodiazepine receptor binding in 17 male patients, including 3 receiving and 14 not receiving disulfiram. All patients studied with FMZ were also examined with fluorodeoxyglucose. PET studies of ICMRglc revealed significantly decreased global values in the patients receiving disulfiram compared with those not receiving disulfiram. PET studies of benzodiazepine receptor binding revealed decreased flumazenil influx and distribution volume in patients receiving disulfiram. The neuropsychological tests demonstrated no differences between the two groups of subjects. The findings suggest that disulfiram may influence the results of PET studies of glucose metabolism and benzodiazepine receptor binding.

Adult↗
PubMed1995

Low grade gliomas: preliminary analysis of failure patterns among patients treated using 3D conformal external beam irradiation.

PURPOSE: The pattern of failure of low grade gliomas following radiotherapy is less well known than that of the high grade gliomas. Stereotactic histologic studies have suggested that tumor cells extend beyond imaging abnormalities, and that large margins would be required for radiotherapy target volumes to encompass all of the neoplasm. Our experience using computerized tomography (CT)- and magnetic resonance (MR)-planned irradiation of low grade gliomas was reviewed to determine the pattern of tumor recurrence, in an effort to clinically define the minimum margin required. METHODS AND MATERIALS: Forty-six patients with low grade supratentorial gliomas were treated between April 1985 and November 1992 using three-dimensional (3D) conformal CT- or MR-planned external beam radiotherapy. Fields were designed to encompass a target volume created by adding a margin to the tumor in three dimensions. Generally, patients were treated using shrinking fields with an initial target (tumor plus a 1 to 3 cm margin) treated to a dose of 45 to 50.4 (median 50.4) Gy, and a boost (tumor plus a 0 to 2 cm margin) treated to a total of 54 to 59.4 (median 59.4) Gy. Median follow-up was 32.9 months. RESULTS: There have been 11 failures; all of these occurred within the radiographic abnormality (either T2 prolongation or CT hypodensity) visualized at the time of treatment planning (i.e., all failures were within the boost volume). Median time to failure was 53 months. Because all failures were local, there was no relationship between the amount by which the tumor volumes were expanded to create target volumes and the eventual outcome. CONCLUSION: Despite pathologic data suggesting that low grade glioma cells can be found outside the MR T2-signal abnormality in many cases, our results demonstrate that conformal external beam radiotherapy, in which the high dose volume is limited, does not result in increased marginal or out-of-field failures. Until control of tumor within the radiographically abnormal volume can be achieved, the need for large fields to treat prophylactically microscopic disease beyond the visualized tumor volume is questionable. The use of conformal fields might be associated with reduced toxicity, and thereby allow delivery of higher total doses to the central tumor.

Adolescent↗
PubMed1995

Benzodiazepine receptor binding in cerebellar degenerations studied with positron emission tomography.

We used positron emission tomography with [11C]flumazenil to study gamma-aminobutyric acid type A/benzodiazepine receptor binding quantitatively in the cerebral hemispheres, basal ganglia, thalamus, cerebellum, and brainstem of 72 subjects, including 14 with multiple system atrophy of the ataxic (olivopontocerebellar atrophy) type, 5 with multiple system atrophy of the extrapyramidal/autonomic (Shy-Drager syndrome) type, 18 with sporadic olivopontocerebellar atrophy, 15 with dominantly inherited olivopontocerebellar atrophy, and 20 normal control subjects with similar age and sex distributions. In comparison with data obtained from the normal control subjects, we found significantly decreased ligand influx in the cerebellum and brainstem of multiple system atrophy patients of the olivopontocerebellar atrophy type and in patients with sporadic olivopontocerebellar atrophy, but not in patients with multiple system atrophy of the Shy-Drager syndrome type. Despite these differences in ligand influx, benzodiazepine binding was largely preserved in the cerebral hemispheres, basal ganglia, thalamus, cerebellum, and brainstem in patients with multiple system atrophy of both types as well as those with sporadic or dominantly inherited olivopontocerebellar atrophy as compared with normal control subjects. The finding of relative preservation of benzodiazepine receptors indicates that these sites are available for pharmacological therapy in these disorders.

Adult↗
PubMed1995

Age influences chemotherapy response in astrocytomas.

OBJECTIVE: In patients with cerebral astrocytomas treated with nitrosourea-based chemotherapy, to determine whether age is predictive of response, time to progression, survival, or rate of complications. DESIGN: Retrospective analysis of neuroimaging studies and clinical data. SETTING: University hospital with a busy neuro-oncology service. PATIENTS: One hundred forty-eight patients with pathologically confirmed malignant astrocytomas or recurrent astrocytomas. RESULTS: Partial response occurred in 39% of patients aged < 40 years, in 17% of those aged 40 to 59, and in only 5% of those aged > or = 60 (p < 0.001). Median time to progression after chemotherapy was 23 weeks in patients aged < 60 and 6 weeks in patients aged > or = 60 (p < 0.001). Median survival after chemotherapy was 43 weeks in patients aged < 60 but only 24 weeks in patients aged > or = 60 (p < 0.001). Differences between age groups in response rate, time to progression, and survival persisted with adjustment for tumor grade. The risk of myelosuppressive complications requiring hospitalization was significantly related to age (p = 0.03); such complications occurred in 35% of patients aged > or = 60 and 16% of patients under 60 years. CONCLUSION: Age is strongly predictive of the likelihood of a response to chemotherapy, time to progression, survival, and risk of myelosuppressive complications. Patients aged > or = 60 have a lower change of benefit and an increased risk of myelosuppressive complications from chemotherapy for astrocytomas compared with younger patients.

Adolescent↗
PubMed1995

A comparison of cerebral blood flow and glucose metabolism in olivopontocerebellar atrophy using PET.

OBJECTIVE: In sporadic cases of olivopontocerebellar atrophy (OPCA), to determine whether local cerebral blood flow (lCBF) is reduced, whether lCBF is coupled to local cerebral metabolic rate for glucose (lCMRglc), and whether lCBF measurements are potentially useful in diagnosing OPCA. DESIGN: Positron emission tomography was used with [15O]H2O to measure lCBF and with [18F]fluorodeoxyglucose to measure lCMRglc in 17 patients with OPCA and 21 normal control subjects. RESULTS: In OPCA patients, lCBF was significantly decreased in the cerebellum, but not in the cerebral cortex, basal ganglia, thalamus, or brainstem. In the same patients, lCMRglc was significantly decreased in the cerebellum and brainstem, where the largest changes were observed, and also in the cerebral cortex, basal ganglia, and thalamus. The ratio of lCBF to lCMRglc, an indicator of the coupling of blood flow to metabolism, was similar in OPCA patients and normal subjects for all regions except the brainstem, where the ratio was marginally decreased in OPCA patients. Using logistic discriminant analysis to assess the ability of lCBF and lCMRglc to differentiate OPCA patients from normal subjects, we found the cross-validated sensitivity of absolute lCMRglc as a predictor of OPCA was 82% with a corresponding specificity of 71%; the sensitivity of absolute lCBF was 71% and the specificity 76%. CONCLUSIONS: In sporadic cases of OPCA, lCBF is reduced in the cerebellum, CBF remains coupled to lCMRglc, and the lCBF pattern is a useful predictor of the diagnosis.

Aged↗
PubMed1995

PET of peripheral benzodiazepine binding sites in the microgliosis of Alzheimer's disease.

UNLABELLED: Animal and human autoradiographic studies have shown increased in vitro binding of the peripheral benzodiazepine binding site antagonist PK 11195 in areas of microgliosis, including the temporal association cortex of patients with Alzheimer's disease. To further elucidate the role of cellular inflammation and microgliosis in Alzheimer's disease during life, we used PET and [11C]PK 11195, a peripheral benzodiazepine receptor ligand known to bind avidly to microglia. METHODS: Eight patients with a diagnosis of probable Alzheimer's disease underwent PET of the brain using [11C]PK 11195 and, for comparison, with [18F]FDG to determine cerebral glucose metabolism. Uptake of [11C]PK 11195 in various brain regions was expressed relative to that in the cerebellum and compared to values determined in one normal elderly subject and in clinically and anatomically unaffected hemispheres of seven patients with small unilateral gliomas. RESULTS: No increases in peripheral benzodiazepine binding were identified in patients with probable Alzheimer's disease, and binding was lowest in regions that were most hypometabolic. CONCLUSION: The peripheral benzodiazepine binding sites associated with microgliosis and cellular inflammation in Alzheimer's disease at postmortem are undetectable by PET using [11C]PK 11195 in patients with mild-to-moderate dementia.

Aged↗
PubMed1994

Structural and functional brain imaging in Friedreich's ataxia.

BACKGROUND: Although the major neuropathologic changes in Friedreich's ataxia (FA) affect the spinal cord and peripheral nerves, we previously found abnormally increased glucose metabolism in the cerebral hemispheres in ambulatory patients and a return toward normal metabolism in nonambulatory patients. OBJECTIVE: To determine whether brain atrophy accompanies the decline in cerebral glucose metabolism in FA and whether the degree of atrophy and the extent of decline in cerebral glucose metabolism are related to clinical severity. DESIGN: Prospective series. SETTING: University referral center. PATIENTS: Twenty-two patients with FA and 26 patients with dizziness, headache, or minor acute head trauma, serving as control subjects, who underwent computed tomographic scans that were interpreted as normal. MEASURES: In patients with FA and control subjects, regional atrophy was assessed using subjective and objective measures on computed tomographic scans. In patients with FA, local cerebral glucose metabolism was measured with positron emission tomography, and clinical severity was assessed with a clinical rating scale. RESULTS: Atrophy in the cerebral hemispheres, cerebellum, and brain stem was significantly greater in patients with FA than in control subjects, and the degree of atrophy correlated with the clinical severity. Local cerebral metabolic rate for glucose declined significantly from the initially elevated levels in the thalamus, cerebellum, and brain stem in correlation with increasing clinical severity. CONCLUSIONS: The structure and function of wide-spread brain regions including the cerebral hemispheres are abnormal in FA, and these abnormalities correlate with the clinical severity.

Adult↗
PubMed1994

Clinical outcome in aggressively treated meningeal carcinomatosis.

OBJECTIVE: To critically evaluate the clinical outcome of patients with cytologically proved meningeal carcinomatosis and to identify factors associated with an improved outcome. DESIGN: A consecutive series of patients was identified from a cytopathology data base. The study period was from 1985 to 1990. Case records and results of radiologic investigations were reviewed; all patients were followed up until their deaths. SETTING: University hospital with a cancer center. PATIENTS: Thirty-six consecutive patients with cytologically proved meningeal carcinomatosis. Patients with lymphoma or leukemia were excluded. INTERVENTIONS: External beam radiation therapy, intrathecal chemotherapy via a ventricular catheter, and intravenous chemotherapy. MAIN OUTCOME MEASURES: Clinical assessment and survival. RESULTS: Symptoms improved in 15% of 33 treated patients. Response to treatment had no clear relationship with the age, site of involvement, or tumor type. Median survival for treated patients was only 9 weeks. Patients who received more than five intrareservoir chemotherapy treatments had a median survival of 23 weeks. Median survival for patients with breast carcinoma who received intravenous chemotherapy was 20 weeks, significantly better than that of patients not receiving intravenous chemotherapy. CONCLUSIONS: Survival is poor despite aggressive treatment. Intravenous chemotherapy may improve survival in patients with chemoresponsive primary tumors and deserves further study.

Adult↗
PubMed1994

Patterns of cerebral glucose metabolism detected with positron emission tomography differ in multiple system atrophy and olivopontocerebellar atrophy.

We used positron emission tomography with [18F]fluorodeoxyglucose to study local cerebral metabolic rates for glucose (ICMRglc) in patients with multiple system atrophy (MSA), sporadic olivopontocerebellar atrophy (sOPCA), and dominantly inherited olivopontocerebellar atrophy (dOPCA) in comparison with normal control subjects. IN MSA, absolute lCMRglc was significantly decreased in the brainstem, cerebellum, putamen, thalamus, and cerebral cortex. In sOPCA, absolute lCMRglc was significantly decreased in the brainstem, cerebellum, putamen, thalamus, and cerebral cortex. In dOPCA, absolute lCMRglc was significantly decreased in the brainstem and cerebellum but not in the other structures. Examination of lCMRglc normalized to the cerebral cortex in comparison with normal controls revealed in MSA significant decreases in the brainstem, cerebellum, and putamen but, in both sOPCA and dOPCA, significant decreases only in the brainstem and cerebellum. The findings indicate that these three disorders all show a marked decrease of lCMRglc in the brainstem and cerebellum but differ in the degree of hypometabolism in forebrain and cerebral cortical structures. The results are consistent with the possibility that, in many cases, sOPCA will evolve into MSA. Moreover, positron emission tomography may provide helpful diagnostic information in these neurodegenerative diseases.

Adult↗
PubMed1994

Radiosensitization with carotid intra-arterial bromodeoxyuridine +/- 5-fluorouracil biomodulation for malignant gliomas.

Bromodeoxyuridine (BUdR), a nonhypoxic radiosensitizing drug, is a halogenated pyrimidine analog that is incorporated into the DNA of dividing cells in a competitive process with thymidine. BUdR sensitizes cells to radiation therapy. 5-Fluorouracil (5-FU) inhibits the endogenous synthesis of thymidine, resulting in increased incorporation of the BUdR. Neurons and glial cells have a very low mitotic rate; they will not incorporate BUdR and will not be sensitized. BUdR and 5-FU are best delivered intra-arterially (IA) because of their regional advantage. We infused BUdR +/- 5-FU over 8 1/2 weeks, before and during 59.4-Gy focal conformal external beam radiation therapy, through a permanently implanted pump with a catheter placed retrograde through the external carotid artery to the carotid bifurcation. Sixty-two patients with grades III or IV glioma were entered into one of two trials, with 23 patients receiving BUdR alone and 39 patients receiving BUdR + 5-FU. The maximum tolerated dose (MTD) of BUdR alone was 400 mg/m2/d for 8 1/2 weeks. The Kaplan-Meier median survival (KMS) was 20 months. In the BUdR + 5-FU trial, the MTD of BUdR was also 400 mg/m2/d and 5-FU was 5 mg/m2/d with a KMS of 17 months. The KMS of all 62 patients in both trials 1 and 2 was 18 months. Pathologic grading used both the original World Health Organization (WHO) and 1993 modified WHO systems. The KMS of grade IV patients was 13.8 months (48 patients) with the original system and 17 months (58 patients) with the modified system.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Comparison between BCNU and procarbazine chemotherapy for treatment of gliomas.

We compared sequential single-agent BCNU and procarbazine (PCB) chemotherapy in 31 patients with gliomas [grade IV (10), grade III (15), grade II (6)]. Patients had failed surgical biopsy +/- resection and radiation therapy. All patients were treated initially with BCNU 150-300 mg/m2 by intra-arterial or intravenous route every 6 weeks. After CT evidence of tumor progression, all patients received PCB 150 mg/m2/day for 28 days every 8 weeks. Patient responses to BCNU were CR (0), PR (7), SD (12), progression (12), and to PCB CR (2), PR (9), SD (6), and progression (14). Kaplan-Meier estimates of median time to failure for all patients were shorter for BCNU, 5.0 months (range 1.5-20), than for PCB, 6.0 months (range 2-50+). There was a statistically significant difference (Mantel-Cox test, p = 0.02) in the distribution of time to disease progression between the two drugs, especially for grade III tumors (p = 0.02). The cumulative proportion of patients without disease progression at 6 months was 26% while on BCNU, compared to 48% while on PCB; at 12 months the cumulative proportions were 3% for BCNU compared to 35% for PCB. Although there was no formal washout period between administration of the two drugs, no carryover effect was evident. These data provide further evidence that PCB has significant activity against malignant glioma and may, in fact, be more effective than BCNU.

Adult↗
PubMed1992

Clinical outcome in aggressively treated meningeal gliomatosis.

We reviewed 11 consecutive patients with an antemortem cytologic diagnosis of meningeal gliomatosis. In three patients, meningeal gliomatosis was diagnosed before surgical resection of the glioma. Three of five patients with anaplastic astrocytoma and one with oligodendroglioma improved with treatment. Patients with glioblastoma multiforme did not respond and had a median survival from the diagnosis of meningeal gliomatosis of only 8 weeks. Meningeal gliomatosis can be an early finding in gliomas. Treatment response is probably related to tumor histology and grade.

Adolescent↗
PubMed1991

Acute pandysautonomic neuropathy.

Acute pandysautonomic neuropathy is characterized by severe postganglionic sympathetic and parasympathetic dysfunction, with relative or complete sparing of motor and sensory function. Of four reported cases with sural nerve biopsies, two were normal and two abnormal, revealing loss of small myelinated and unmyelinated fibers. We present a patient with pandysautonomic neuropathy and elevated CSF protein whose sural nerve biopsy showed active axonal degeneration.

Acute Disease↗
PubMed1990

Neuropsychological changes in olivopontocerebellar atrophy.

We used standardized neuropsychological measures of intellectual, cognitive, psychomotor, and emotional functioning to compare 39 patients with olivopontocerebellar atrophy and 25 normal controls of similar age. The patients reflected greater depression, anxiety, and subjective emotional discomfort than did the control subjects. While 4 of the patients had below-normal IQ scores (Wechsler Adult Intelligence Scale [WAIS-R] Full-Scale IQ [FSIQ] less than 80), their clinical histories suggested lifelong functioning at such levels. As a group, the patients were not abnormal in general intellectual functioning and related cognitive abilities (WAIS-R FSIQ, mean [+/- SD], 93.46 +/- 13.19; Wechsler Memory Scale mental quotient, 108.95 +/- 17.43). These scores were lower than those of the normal controls (WAIS-R FSIQ, 113.72 +/- 12.68; mental quotient, 127.80 +/- 12.40); however, the controls were a highly educated group with intelligence levels that were higher than those of the average population. Moreover, when education and motor dysfunction were statistically covaried, no significant differences between the patients and the normal controls were apparent on the cognitive and intellectual tasks. Further analysis of specific memory performance in a subgroup of patients and controls matched for age, sex, and education yielded findings that were comparable with the overall group analysis. We conclude that motor dysfunction and depressed mood could leave patients with olivopontocerebellar atrophy appearing to be impaired in memory, even demented, when they are not.

Adult↗
PubMed1990

The Marinesco-Sjögren syndrome examined by computed tomography, magnetic resonance, and 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography.

The Marinesco-Sjögren syndrome is an autosomal recessive degenerative disorder characterized by congenital cataracts, cerebellar ataxia, spasticity, mental deficiency, and skeletal abnormalities. We studied two adult siblings with Marinesco-Sjögren syndrome using anatomic and metabolic brain imaging techniques to characterize the pattern and nature of abnormalities in the brain. Computed tomographic and magnetic resonance imaging showed diffuse brain atrophy of mild to moderate degree, involving primarily the white matter of the cerebrum, cerebellum, brain stem, and cervical spinal cord. The pattern of atrophy resembled that seen in diffuse leukoencephalopathies. Measurements of local cerebral glucose metabolic rates with positron emission tomography revealed no statistically significant differences from normal control subjects in most regions, but metabolic rate was decreased in the thalamus in one patient. The findings support a diffuse white matter disorder in Marinesco-Sjögren syndrome.

Adult↗