Evaluation of a double-injection method for sequential measurement of cerebral blood flow with iodine-123-iodoamphetamine.

Unlabelled: To test the feasibility of applying N-isopropyl-[123I]p-iodoamphetamine (IMP) for sequential measurements of regional cerebral blood flow (rCBF) with injection of two separate doses in a single procedure, kinetic analysis based on a two-compartment model was done using dynamic SPECT data. A microsphere model analysis without consideration of IMP washout from the brain was also tested for clinical application.

Methods: A dynamic SPECT scan consisting of fifty 1-min scans was obtained on 15 patients using a three-head rotating gamma camera with two separate doses of IMP (111 MBq each) at the beginning and 25 min after scan initiation.

Simple quantification of benzodiazepine receptor binding and ligand transport using iodine-123-iomazenil and two SPECT scans.

Unlabelled: The feasibility of simplified procedures for the quantification of benzodiazepine receptor binding using [123I]iomazenil and SPECT was assessed.

Methods: Six normal male volunteers were studied. Following intravenous injection of 111 MBq [123I]iomazenil, serial dynamic SPECT scanning was performed for 120 min and the concentration of lipophilic compounds in the arterial plasma was determined by chloroform extraction.

Cortical activation with sound stimulation in cochlear implant users demonstrated by positron emission tomography.

Six postlingually deaf patients using multi-channel cochlear implants were examined by positron emission tomography (PET) using 15O-labeled water. Changes in regional cerebral blood flow (rCBF) were measured during different sound stimuli. The stimulation paradigms employed consisted of two sets of three different conditions; (1) no sound stimulation with the speech processor of the cochlear implant system switched off, (2) hearing white noise and (3) hearing sequential Japanese sentences.

Clinical application of 62Zn/62Cu positron generator: perfusion and plasma pool images in normal subjects.

We have developed a new 62Zn/62Cu positron generator, and applied it for PET imaging of perfusion and plasma volume in 5 normal subjects. The generator makes it possible by a simple procedure to obtain 62Cu eluate and labeling compounds sufficiently every 40-60 minutes. 62Cu labeled pyruvaldehyde bis(N4-methylthiosemicarbazone) copper II (62Cu-PTSM) was employed for cerebral and myocardial perfusion imaging and 62Cu labeled human serum albumin-dithiosemicarbazone (62Cu-HSA-DTS) was used for plasma pool imaging.

Limited value of interictal brain perfusion SPECT for detection of epileptic foci: high resolution SPECT studies in comparison with FDG-PET.

Accurate localization of epileptic foci is important for pre-surgical evaluation of patients with medically intractable epilepsy, and F-18 FDG PET has been proved to be a valuable method for this purpose. To examine the clinical value with interictal brain perfusion SPECT, we performed brain perfusion SPECT of Tc-99m HMPAO by means of a high resolution SPECT camera, and compared the results with F-18 FDG PET images and MRI in 10 patients with medically intractable epilepsy. In 9 of 10 patients (90%), FDG PET images showed focal hypo-metabolism in the area corresponding with the results of electroencephalography (EEG).

[Phase 1 clinical study of 123I-iomazenil: a new probe to evaluate central-type benzodiazepine receptor with SPECT].

A Phase 1 clinical study of 123I-iomazenil (IMZ), a new radiopharmaceutical developed for evaluation of central-type benzodiazepine receptor (BZR) with SPECT, was performed to examine its safety and biodistribution in six healthy volunteers. The brain uptake of 123I-IMZ reached a maximum value of 11.7 +/- 1.

Clinical application and quantitative evaluation of generator-produced copper-62-PTSM as a brain perfusion tracer for PET.

Unlabelled: Copper-62-pyruvaldehyde bis(N4-methylthiosemicarbazone) copper II (62Cu-PTSM) has been proposed as a generator-produced positron-emitting tracer for perfusion imaging. To evaluate the characteristics of 62Cu-PTSM as a cerebral perfusion tracer, brain PET images of 62Cu-PTSM were compared with cerebral blood flow (CBF).

Methods: Following an intravenous injection of 62Cu-PTSM, a serial dynamic PET scan was performed for 10 min with arterial sampling in 10 subjects.

Optimal dose of injection in activation study with O-15 water and PET.

In activation studies with the bolus method for O-15 water and PET, the radiotracer concentration may reach the limits of the system in terms of dead time correction and accidental coincidence. To obtain the optimal injection dose of O-15 water, we performed a normal volunteer study to evaluate the relationship between the injected dose and the radioactivity concentration in the brain and a phantom study to evaluate the performance of the PET scanner (PCT3600W) under high count rate conditions and the effect of averaging on the signal to noise ratio for the PET images. A linear relationship was noted between the injected dose (normalized for each body weight: x) and the mean radiotracer concentration in the brain measured by PET (y) (y = 2.

Gene regulation of trkB and trkC in the chick retina by light/darkness exposure.

The trk gene family members; the neurotrophic receptors for neurotrophins, are implicated in the survival and the differentiation of neurons. The roles of these protooncogenes have been argued in the pathological conditions and in the specific developmental stage when the programmed cell death occurs to neurons. Here we studied a physiological role of the trk family members in the retina through observations of their gene regulation by light/darkness exposure.

Effects of hyperglycemia on FDG uptake in human brain and glioma.

Unlabelled: This study evaluates the effects of hyperglycemia on fluorodeoxyglucose (FDG) uptake in the human brain and in brain tumors.

Methods: We performed glucose loading during FDG PET studies in nine patients with brain tumors (eight gliomas and one brain metastasis) and one with resected glioma. Two FDG PET scans were obtained in all cases within 1 wk in a control state and with glucose loading by intravenous infusion of 10% glucose solution.

Enhanced detection of brain tumors by [18F]fluorodeoxyglucose PET with glucose loading.

Objective: We applied glucose loading during PET studies with [18F]2-fluoro-2-deoxy-D-glucose (FDG) to enhance detection of brain tumors by diminution of FDG uptake in normal gray matter.

Materials And Methods: This study involved three patients with glioblastomas. Two PET scans were performed in all cases within 1 week in control and with glucose loading state.

Molecular control of neuronal survival in the chick embryo.

Neurotrophins are structurally related proteins which promote the survival and differentiation of specific neuronal populations during the development of vertebrate embryos. Like many growth factors, the neurotrophins mediate their actions by binding to membrane proteins that have a ligand-activated tyrosine kinase activity. The interactions of the neurophins with their neuronal receptors have been mostly studied using chick embryonic neurons.

Hybrid cell extinction and re-expression of Oct-3 function correlates with differentiation potential.

The Oct-3 gene is expressed in highly undifferentiated cells and is implicated in mammalian early embryogenesis. We have generated a series of hybrid cells between pluripotent embryonal carcinoma cells (Oct-3+) and fibroblasts (Oct-3-), and have studied the regulation and function of Oct-3. Upon fusion, the hybrid cells differentiated to nestin+/Brn-2+ cells resembling neuroepithelial stem cells.

Expression and binding characteristics of the BDNF receptor chick trkB.

Previous studies using transfected cells have indicated that the mammalian receptor tyrosine kinase trkB binds the neurotrophins brain-derived neurotrophic factor, neurotrophin-3 and neurotrophin-4. However, most studies demonstrating that these neurotrophins prevent the death of embryonic neurons and have specific neuronal receptors have been performed with chick neurons. In order to explore the possibility that trkB is the molecular entity representing the high-affinity receptor for brain-derived neurotrophic factor on embryonic chick neurons, we cloned and expressed a chick trkB cDNA.

Molecular cloning and expression of a novel truncated form of chicken trkC.

The trk family of tyrosine protein kinase genes serves crucial roles for the development of the nervous system and the survival of neurons. The members of this gene family, trk, trkB and trkC, bind a distinct neurotrophin of the nerve growth factor (NGF) gene family, and trigger the intracellular signals which elicit trophic and differentiating effects on neurons. Adding to these neurotrophic receptor kinases, the truncated forms without the tyrosine kinase domain have been cloned and characterized.

trk immunoreactivity at neuronal dendrite and cell body.

Neurotrophins homologous to the nerve growth factor (NGF) bind the neurotrophic receptors of the trk gene family. Since the target tissues release these neurotrophic factors to the neuron, it has been believed that their trophic effects are mediated by the retrograde axonal transport. However it remains an open question whether the neurotrophins act through the autocrine or the paracrine mechanisms, since the protein-level expression of trk has not been studied so far.

Dopaminergic stimulation up-regulates the in vivo expression of brain-derived neurotrophic factor (BDNF) in the striatum.

We investigated the effect of dopamine on the in vivo expression of brain-derived neurotrophic factor (BDNF) in the striatum of mouse. BDNF mRNA expression in the striatum, which was quantified with the reverse transcriptase polymerase chain reaction, was up-regulated from 2 h after oral administration of levodopa, a precursor of dopamine. The increase was sustained for 16 h.

[XYY syndrome associated with motor neuropathy].

We described a case of XYY syndrome associated with motor neuropathy. The case was a 27-year-old male, who had 47-XYY chromosome karyotype. His symptoms were distal dominant muscle weakness and muscle atrophy in his lower extremities without objective sensory disturbance.

The oct3 gene, a gene for an embryonic transcription factor, is controlled by a retinoic acid repressible enhancer.

Oct3 is an embryonic octamer-binding transcription factor, whose expression is rapidly repressed by retinoic acid (RA). In this report, we have determined the transcriptional control region of the oct3 gene and studied the mechanism of the RA-mediated repression. The chromosomal oct3 gene consists of five exons.

[A case of Crow-Fukase syndrome with increased serum interleukin-6].

We experienced a 47-year-old Japanese female with polyneuropathy, edema, hypertrichosis, hyperpigmentation, and white nail, which were diagnostic as having Crow-Fukase syndrome. Laboratory and radiological evaluation showed neither plasma cell dyscrasia nor monoclonal gammopathy. Increased factor VIII activity and thrombocytosis, which suggested thrombotic tendency, were observed at the exacerbation of clinical symptoms.

[Therapy of malignant pheochromocytoma using I-131 metaiodobenzylguanidine--report of a case].

A 67 year-old-female had multiple metastases to her lung, liver and paraaortic lymph nodes from a post-operative malignant pheochromocytoma. She was treated with 3.7 GBq (100 mCi) of I-131 metaiodobenzylguanidine (MIBG).

A novel octamer binding transcription factor is differentially expressed in mouse embryonic cells.

We have identified a novel octamer binding factor (Oct-3) in P19 embryonal carcinoma cells. Oct-3, which recognizes the typical octamer motif (ATTTGCAT) as well as the AT-rich sequence TTAAAATTCA, is present in P19 stem cells but disappears when the cells are induced to differentiate by retinoic acid (RA). Cloned cDNA corresponding to Oct-3 encodes a protein of 377 amino acids.

[31P-NMR spectroscopy of mitochondrial myopathies: the relation between abnormal energy metabolism and muscle biopsy findings].

31P-NMR spectra were obtained from the quadriceps femoris muscle (at rest and after aerobic exercise) of the 7 cases of mitochondrial myopathies (2 cases of mitochondrial encephalomyopathy and lactic acidosis(MELA), 1 case of myoclonus epilepsy with regged red fiber, 1 case of Kearns-Sayre syndrome, 3 cases of progressive external ophthalmoplegia), using superconducting whole body MR (Magnetom, Siemens). One case showed abnormally low Pcr/Pi ratio in the resting state. An aerobic exercise using ergometer was performed on the other 6 patients.