Protective effect of nimodipine against quinolinic acid-induced damage of rat hippocampus in vitro.

The study was undertaken to examine the effect of nimodipine, calcium channels blocker, on the morphological alterations induced by quinolinic acid (QUIN). The experiment was performed on 21-day-old organotypic rat hippocampal cultures. Nimodipine was applied to the nutrient medium simultaneously with QUIN (both at 100 microM). Ultrastructural changes were evaluated 24 h, 5 and 7 days after the exposure to tested agent. It was shown that nimodipine induced distinct cytoprotective effect, especially considering the development of late neurotoxic injury produced by QUIN. However, the protection was not complete, indicating the participation of the other factors in the pathomechanism underlying structural damage produced by QUIN.     

Interstitial hyperthermia of malignant brain tumors using implant heating system (IHS)

We have developed an implant heating system (IHS) for interstitial hyperthermia of brain tumors. IHS consists of three compartments: ferromagnetic implant with low Curie point, induction coil and generator to produce high frequency magnetic field. The device works as follows: It is heated up to a Curie temperature (Tc) by Eddy current under the magnetic field. Heat generated in the implant is conducted to the tumor tissue into which it has been implanted. To evaluate the effect of this hyperthermia, a brain tumor model was produced by innoculation of VX2 tumor cells and treated either by hyperthermia with IHS alone, chemotherapy with ACNU alone, or with a combination of both. The longest survival was obtained by the combined treatment, and significant prolongation of survival was found in the single treatment groups. In the Phase I clinical trial, one or several implants (1.8 mm X 15 mm, Tc = 68 degrees C) made of Fe-Pt alloy were placed in the tumor by CT guided stereotactic procedure, or manually during craniotomy. Hyperthermia of above 42 degrees C for 30 to 60 minutes twice a week was brought about in ten cases of malignant brain tumor. CT evaluation was made in nine cases treated for more than ten times in this way. Five out of the nine cases responded to this hyperthermia with irradiation. In conclusion, a safe, repeated and longterm treatment was possible without significant side effects. The hyperthermia with IHS may also be applicable to benign intracranial tumors and neoplasms in other part of body as well.     

Differential modulation of the short- and long-latency somatosensory evoked potentials in a forewarned reaction time task.

OBJECTIVE: We investigated modulation of the short- and long-latency somatosensory evoked potentials (SEPs) in a forewarned reaction time task. METHODS: A pair of warning (auditory) and imperative stimuli (somatosensory) was presented with a 2 s interstimulus interval. In movement condition, subjects responded by grip movement with the ipsilateral hand to the somatosensory stimulation when the imperative stimulus was presented. In counting condition, they silently counted the number of imperative stimuli. The SEPs in response to the imperative stimuli were recorded. RESULTS: Frontal N30 and central N60 amplitudes were significantly smaller in the movement than in the counting or rest conditions. None of the short-latency components differed between the counting and rest conditions. In contrast to the short-latency components, P80 was significantly larger in the counting than in the rest condition, and showed a further increase from the counting to the movement condition. The N140 amplitude was significantly larger in the movement than the rest condition, but was not changed between the counting and the rest conditions. CONCLUSIONS: The attenuation of the frontal N30 and central N60, and the enhancement of the P80 and possibly the N140 resulted from the centrifugal mechanism. The present findings may show the different effects of voluntary movement on the early and subsequent cortical processing of the relevant somatosensory information requiring a behavioral response. SIGNIFICANCE: The present study demonstrated the differential modulation of short- and long-latency components of SEPs in a forewarned reaction time task.     

A case of primary hypothyroidism with repeated episodes of respiratory failure

A case of repeated episodes of hypoventilatory respiratory failure accompanied with primary hypothyroidism was reported. A 76-year-old woman was admitted to our hospital due to both disturbance of consciousness and respiratory failure. A diagnosis of primary hypothyroidism complicated with hypoventilatory respiratory failure deterioration due to respiratory infection was made. Supplemental therapy of thyroid hormones improved her general condition, but respiratory failure recurred after interruption of a replacement drug. Cases of unexplained respiratory failure should be differentiated from respiratory failure induced by hypothyroidism.     

A trial of semiquantitative analysis of whole body bone scintigraphy in renal osteodystrophy

Four color processed whole body bone scintigraphy with 99mTc-methylene diphosphonate was performed in six patients on maintenance hemodialysis, and the results of semiquantitative colorimetric analysis were compared with those of a normal group. The difference between the two (control and patient group) was statistically significant (P less than 0.01). Furthermore, the effect of 1 alpha-hydroxyvitamin D3 treatment on renal osteodystrophy was evaluated by this method. The results indicated that this method provides a useful method for assessing the response of renal osteodystrophy to treatment. Two representative cases of renal osteodystrophy are presented to illustrate the usefulness of this approach to semiquantitative whole body bone scanning.     

DNA synthesis and related enzymes altered in compensatory lung growth in rats.

Left pneumonectomy was performed on 4 week-old male Fischer-344 rats. Changes in DNA biosynthesis and the activities of related enzymes were studied in the contralateral lungs of the pneumonectomized animals (n = 55) and compared with sham-operated (n = 55) and untreated control animals (n = 40) The wet weight of the contralateral lung of the pneumonectomized rats reached that of both lungs of the untreated and sham-operated rats 14 days after the operation. The activities of thymidine kinase and DNA polymerase from the regenerating lungs were elevated on Days 1 and 7. To determine the molecular forms of DNA polymerase in the crude extract, phosphocellulose column chromatography was performed. The type of DNA polymerase with the highest activity was alpha in regenerating lung on Days 1, 3, and 7. These results suggest that DNA replication for cellular proliferation was elevated in the remaining lung after pneumonectomy. In addition, an interlobar difference in DNA biosynthesis was observed in the remaining lung. The increase was especially marked in the cardiac lobe, followed by increases in the DNA content of the remaining lobes on Day 7. From these observations we conclude (1) that increased activity of DNA polymerase alpha is likely to be an initial change in compensatory lung growth, and may be caused by some unknown stimulator in lung tissue, and (2) that DNA biosynthesis may differ among the lobes of the lung, at least until 3 days post-pneumonectomy.     

Dynamics of changes in blood flow, volume, and oxygenation: implications for dynamic functional magnetic resonance imaging calibration.

Changes in cerebral blood flow (CBF), volume (CBV), and oxygenation (blood-oxygenation level dependent (BOLD)) during functional activation are important for calculating changes in cerebral metabolic rate of oxygen consumption (CMRo2) from calibrated functional MRI (fMRI). An important part of this process is the CBF/CBV relationship, which is signified by a power-law parameter: gamma=ln (1+DeltaCBV/CBV)/ln (1+DeltaCBF/CBF). Because of difficulty in measuring CBF and CBV with MRI, the value of gamma is therefore assumed to be approximately 0.4 from a prior primate study under hypercapnia. For dynamic fMRI calibration, it is important to know if the value of gamma varies after stimulation onset. We measured transient relationships between DeltaCBF, DeltaCBV, and DeltaBOLD by multimodal MRI with temporal resolution of 500 ms (at 7.0 T) from the rat somatosensory cortex during forepaw stimulation, where the stimulus duration ranged from 4 to 32 secs. Changes in CBF and BOLD were measured before the administration of the contrast agent for CBV measurements in the same subjects. We observed that the relationship between DeltaCBF and DeltaCBV varied dynamically from stimulation onset for all stimulus durations. Typically after stimulation onset and at the peak or plateau of the DeltaCBF, the value of gamma ranged between 0.1 and 0.2. However, after stimulation offset, the value of gamma increased to 0.4 primarily because of rapid and slow decays in DeltaCBF and DeltaCBV, respectively. These results suggest caution in using dynamic measurements of DeltaCBF and DeltaBOLD required for calculating DeltaCMRo2 for functional stimulation, when either DeltaCBV has not been accurately measured or a fixed value of gamma during hypercapnia perturbation is used.     

STANDARD IMAGING TECHNIQUES OF ENDOSCOPIC ULTRASOUND‐GUIDED FINE‐NEEDLE ASPIRATION USING A CURVED LINEAR ARRAY ECHOENDOSCOPE

Standard imaging techniques using a curved linear array echoendocope are summarized to facilitate the attainment of expertise in endoscopic ultrasonography and endoscopic ultrasound‐guided fine needle aspiration, and to promote the widespread use of this diagnostic and therapeutic tool. Typical images of the mediastinal organs, the bilio‐pancreatic systems and neighboring organs by scanning from the esophagus, stomach, duodenal bulb, and descending portion of the duodenum, are shown in a sequential manner. The basic techniques of endoscopic ultrasound‐guided fine needle aspiration are also presented.