Use of MR angiography in a pregnant patient with thalamic AVM

A 32-year-old pregnant woman at 29 gestational weeks suffered from the acute onset of severe headache. Brain CT, MRI, and MR angiography (MRA) showed intraventricular and thalamic hemorrhage, ruptured from a thalamic AVM. Based on these findings, conservative treatment was continued until delivery. After cesarean delivery at 34 gestational weeks, conventional cerebral angiography was performed, followed later by gamma-knife therapy. In pregnant patients with suspected cerebrovascular disorders, MRI and MRA should be the first of choice method to evaluate information on the diseased vessels and associated lesions since there is no radiation risk or side effects of contrast medium.

Effects of aging on P3 components of somatosensory event-related potentials elicited by different stimulus conditions. Conventional averages and single-trial analysis

Effects of aging on P3 components of somatosensory event-related potentials (ERPs) under different stimulus conditions were studied in healthy subjects using conventional averages and single-trial waveform analysis. The P3 component elicited by target stimuli (target P3) and that elicited by rare nontarget stimuli (nontarget P3) showed significant latency prolongation with age at the rate of 1.6 and 2.0 ms/year, respectively. The nontarget P3 showed a greater trial-to-trial fluctuation of single-trial latency than the target P3, probably because 'passive attention' was more liable to fluctuate. The variabilities of single-trial target P3 latency and of single-trial nontarget P3 latency were not correlated with age. Thus, the P3 latency prolongation with age might not be attributable to fluctuation in latency resulting from impairment of attention with aging.

Development of fat within a meningioma

We report a tentorial meningioma containing fat. Multiple areas of fatty density or intensity in the tumour were seen on CT and MRI, which corresponded histologically to lipomatous components. CT 10 years previously had demonstrated a smaller tumour without evidence of fatty components. We found only five cases in the literature in which fatty density was demonstrated within a meningioma on CT and a lipomatous component histologically proved. Xanthomatous change, with lipid in tumour cells, causes decrease in density on CT, but not to the levels of fat. As both lipomatous components and xanthomatous change show similar intensity on MRI, CT can be helpful in differentiating these two conditions. To our knowledge, our case is the only one in which the advent of fatty tissue was confirmed during follow-up.

High-resolution CT findings in the development of the sphenooccipital synchondrosis

PURPOSE

To evaluate the development of the sphenooccipital sychondrosis as seen on high-resolution thin-section CT scans.

METHODS

We retrospectively reviewed the records of 253 patients, ages 1 to 77 years old, who had had thin-section CT examination of the skull base.

RESULTS

An ossification center appeared midline in the patients who were 8 to 13 years old. Six of 12 girls showed additional symmetric ossification centers on either side of the midline; however, this pattern was not seen in boys. No sphenooccipital synchondrosis persisted in any patient past the age of 13 years.

CONCLUSION

High-resolution CT scans of the skull base can show a pattern of progressive ossification of the sphenooccipital synchondrosis, which can be readily recognized and predicted.

Characterization of edema by diffusion-weighted imaging in experimental traumatic brain injury

The objective of this study was to use diffusion-weighted magnetic resonance imaging (DWI) to help detect the type of edema that develops after experimental trauma and trauma coupled with hypotension and hypoxia (THH). Reduction in the apparent diffusion coefficients (ADCs) is thought to represent cytotoxic edema. In a preliminary series of experiments, the infusion edema model and middle cerebral artery occlusion models were used to confirm the direction of ADC change in response to purely extracellular and cytotoxic edema, respectively. The ADCs increased (p<0.05) in the case of extracellular edema and decreased (p<0.001) in cytotoxic edema. Following these initial experiments, a new impact acceleration model was used to induce traumatic brain injury. Thirty-six adult Sprague-Dawley rats were separated into four groups; sham, trauma alone, hypoxia and hypotension (HH), and THH. Following trauma, a 30-minute insult of hypoxia (PaO2 of 40 mm Hg) and hypotension (mean arterial blood pressure (MABP) of 30 mm Hg) were imposed and the animals were resuscitated. The DWI was carried out at four 1-hour intervals postinjury, and MABP, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cerebral blood flow (CBF) were monitored. The ADCs in the control and HH groups remained unchanged. The ADCs in the THH group rapidly decreased from a control level of 0.68 +/- 0.05 x 10(-3) mm2/second to 0.37 +/- 0.09 x 10(-3) mm2/second by 3 hours posttrauma (p < 0.001). In this group, the decreased CBF and CPP during secondary insult remained low despite resuscitation, with the ICP increasing to 56 +/- 7 mm Hg by 3 hours. In the trauma alone group, the rise in ICP reached a maximum value (28 +/- 3 mm Hg) at 30 minutes with a significant and sustained increase in CBF despite a gradual decrease in CPP. The ADCs in this group were not significantly reduced. The data lead the authors to suggest that the rise in ICP following severe trauma coupled with secondary insult in this model is predominately caused by cytotoxic edema and that ischemia plays a major role in the development of brain edema after head injury.

Peculiar enlargement of the nasopharynx in patients with anorexia nervosa

We examined the nasopharynx and brain in 17 patients with anorexia nervosa by CT and compared the findings with those of 44 normal subjects and of 5 patients of the same age with marked emaciation caused by various psychiatric disorders. An enlarged nasopharyngeal space with a flattened posterior wall and enlarged lateral pharyngeal recesses were demonstrated in all patients with anorexia nervosa whose weight was lowest at the time of the CT examination, and these CT features regressed or became normal quickly after they had gained some weight. This characteristic enlargement of the nasopharynx and lateral pharyngeal recesses was observed neither in the markedly emaciated patients (2 with schizophrenia, 1 with major depression, 1 with stupor and the other with an extremely unbalanced diet) nor in 44 normal subjects without emaciation. These features were therefore thought to be characteristic and of diagnostic significance.

[Removal of infected pacemaker leads in the elderly under extracorporeal circulation: two case reports and review of Japanese literature]

Two elder cases in whom infected pacemaker leads were removed under extracorporeal circulation (ECC) are reported. The leads could not be with drawn without direct sharp dissection under ECC because they had become firmly encased with fibrous tissue within the right ventricle. Postoperative courses were uneventful and neither of these patients has experienced recurrent infection to date. Removal with ECC seems to be a safe and effective procedure even in the elderly, provided that cardiac function is good.

Results with the currently used cochlear implant

Over the past 7 years we have implanted the Nucleus multichannel cochlear implant in 60 patients with severe hearing impairment. The postoperative speech recognition of adult postlingually deaf patients was satisfactory. Adult prelingually deaf patients exhibited poorer speech perception than postlingually deaf patients. However, some patients showed better results than expected. The prelingually deaf patients needed a longer rehabilitation period than the postlingually deaf patients. There was considerable variation in performance among the prelingually deaf patients. As for juvenile deaf patients, some showed good speech perception ability, but postoperative rehabilitation took longer. The cooperation of doctors, audiologists, speech therapists, schoolteachers, and family members was essential, and the creation of a cochlear implant center for children is desirable to obtain better rehabilitation. On the questionnaire given to the cochlear implant patients, some complained about their hearing in a noisy environment or while listening to television or music. The present cochlear implant system obviously needs further improvement.

Surgical difficulties and postoperative problems associated with cochlear implants

Since 1987 we have implanted 60 severely hearing-impaired adults with the Nucleus Minisystem-22 cochlear implant. In most cases, the surgical procedures were performed with satisfactory results and very few postoperative problems. The complications associated with cochlear implant surgery include difficulty in drilling the ossified cochlea, electrode displacement, and insufficient insertion of the electrode. Postoperative problems include dizziness, tinnitus, facial nerve spasm, receiver-stimulator migration or extrusion, infection of the scalp flap, and facial nerve palsy. In most cases, these complaints did not develop into serious conditions.

Studies of currently used and experimental cochlear implants

Since 1987 we have inserted multichannel cochlear implants in 60 patients with severe hearing impairment. The surgical procedures were not very difficult, and few postoperative complications were encountered. Postoperative speech recognition by every patients was satisfactory. Nevertheless, some patients complained about their hearing in a noisy environment, or while listening to either TV or music. Consequently, cochlear implants needs further improvement. To improve speech recognition ability, a newly developed experimental system was constructed. Judging from the electrode activation pattern, the new system extracted the features of consonants more successfully than the present system. However, when this new system was installed in cochlear implant patients, no significant improvement in consonant recognition was obtained.

Expression and activity-dependent changes of a novel limbic-serine protease gene in the hippocampus

A novel murine cDNA which encodes a protein designated neuropsin was cloned. Northern and in situ hybridization analyses demonstrated that neuropsin mRNA is expressed specifically in the limbic system of mouse brain and is localized at highest concentration in pyramidal neurons of the hippocampal CA1-3 subfields. Direct hippocampal stimulation and kindling induced by amygdaloid stimulation caused a significant bilateral change in neuropsin mRNA level in the hippocampal pyramidal neurons. The activity-dependent changes and the specific localization indicate that neuropsin is involved in hippocampal plasticity.

Localization of trigeminal sensory innervation to the tongue and pharynx of the cat using horseradish peroxidase as tracer

Trigeminal sensory innervation to the tongue and pharynx was investigated in the cat, using horseradish peroxidase (HRP) as a retrograde tracer. Following HRP application to the tongue, cells were labeled primarily in the posterolateral portion of the trigeminal ganglion. The pharynx was divided according to classical methodology into three regions: the epipharynx (nasopharynx), mesopharynx (oropharynx), and hypopharynx. When HRP was applied to the epipharynx and mesopharynx, HRP-labeled cells were found in the anteromedial and posterolateral portions of the trigeminal nerve, respectively. When HRP was applied to the hypopharynx, a single labeled cell was found in the trigeminal ganglion. These results indicate that trigeminal sensory nerve fibers in the cat branch to the tongue, epipharynx, and mesopharynx, but rarely to the hypopharynx.

In vitro and in vivo effects of somatostatin on the growth of A431 cells

We previously reported that the octapeptide somatostatin (SS) analogue SMS 201-995 (SMS) unexpectedly stimulates the growth of A431 human epidermoid carcinoma cells in vitro. In the present study, we found that both SS-14 and SS-28 also stimulated the growth of A431 cells in vitro. The proliferative effect of SS-28 also stimulated the growth of A431 cells in vitro. The proliferative effect of SS-28 was greater than that of SS-14. In contrast, there was no difference in A431 cell tumor weight or area between the SMS-treated or untreated athymic, tumor-bearing mice. The serum epidermal growth factor (EGF) level of the SMS-treated mice was significantly lower than that of the untreated mice. Decreases in serum EGF may attenuate the proliferative effect of SMS in vivo.

Effect of cholera toxin and pertussis toxin on the growth of A431 cells: kinetics of cyclic AMP and inositol trisphosphate in toxin-treated cells

Cholera toxin and pertussis toxin were inhibitory to the incorporation of thymidine into A431 cells in serum-free culture. Cholera toxin enhanced the growth inhibitory effect of epidermal growth factor (EGF) on A431 cells, whereas pertussis toxin attenuated the effect. Cholera toxin increased the concentration of intracellular cyclic AMP (cAMP) to three-times the initial concentration at 120 minutes and it increased the concentration of intracellular inositol trisphosphate (IP3) rapidly but transiently. Pertussis toxin reduced the concentration of IP3 both in EGF treated and untreated A431 cells at 10 minutes. cAMP was not involved in pertussis toxin-mediated effects. In conclusion, the intracellular cAMP and IP3 concentrations in CT-treated A431 cells are compatible with previous reports regarding the growth inhibitory effects on A431 cells. The inhibitory effect of PTX on the EGF-induced increase of intracellular IP3 is thought to be compatible with the finding that PTX attenuated the EGF-induced growth inhibition.

An early onset of hereditary progressive dystonia with marked diurnal fluctuation: determining clinical status using gait analysis

We report on a 5 year old girl who has hereditary progressive dystonia with marked diurnal fluctuation that improved remarkably after treatment with L-dopa. A gait analysis of the patient was done and we compared her gait patterns with those of a normal child. The following results were obtained. Before L-dopa treatment: (i) knee extension time was prolonged with genu recurvatum; (ii) the flexors and the extensors were simultaneously activated in the stance phase, and reciprocity between them was impaired; and (iii) recorded sole contact was a toe-only pattern. After L-dopa treatment: (i) the step cycle was shorter mainly due to a shorter knee extension time; (ii) genu recurvatum improved; (iii) reciprocal activities of the flexors and the extensors were observed; and (iv) a normal sole contact pattern was also observed. The data from the gait analysis were useful in stabilizing the subject's clinical condition and in evaluating changes to it.

Rapid and gentle extraction, reconstitution and characterization of microfilament and glia filament from rat astrocytes

We developed gentle and rapid methods for depolymerization and extraction of both microfilament and glia filament separately from a crude cytoskeletal fraction of rat astrocytes. Electron microscopy revealed that the filament reconstituted from the microfilament extract closely resembled F-actin that was formed from G-actin of rabbit skeletal muscle. It was found by immunoblotting analysis that even the reconstituted microfilament-like filaments, which had been purified by affinity chromatography with heavy meromyosin subfragment 1 (S1)-conjugated Sepharose, contained vimentin and glia fibrillary acidic protein (GFAP) besides actin, inferring the interaction between microfilament and glia filament. The filaments (9-10 nm thick) reconstituted from the glia filament extract were composed of actin and other minor components in addition to vimentin and GFAP. Actin, GFAP, 101, 34, 32.5, 30.5, 29.5 and 28 kDa proteins found in the reconstituted glia filament-like filaments were suggested to be glia filament-associated proteins.

Vestibular function in patients with a large vestibular aqueduct

Four patients (7 ears) with a large vestibular aqueduct (VA) were examined for history of vertigo and vestibular function. Vertigo was observed in all the 4 patients. The caloric responses were significantly poorer in ears with a large VA than in the controls. On a patient with a large VA who had several attacks of sudden hearing loss and vertigo following minor head trauma, long-time exposure to sunshine, common cold, and exercise, vestibular function tests were performed several times; the caloric responses were found to fluctuate and direction changing apogeotropic positional nystagmus was observed. These findings suggest that in patients with a large VA, not only hearing but also the vestibular function are generally impaired. We believe than direct transmission of intracranial pressure changes to the inner ear or subsequent inner ear fluid movement through the large endolymphatic sac and duct have an influence on the cochlea and vestibule.