Preheparin serum lipoprotein lipase mass is negatively related to coronary atherosclerosis.

In preheparin serum, there exists lipoprotein lipase (LPL) mass with little activity. The clinical significance of this preheparin serum LPL mass (preheparin LPL mass) is unclear. We studied the levels of preheparin LPL mass in patients with coronary atherosclerosis, comparing the results with those in healthy men. We also evaluated the correlation between preheparin LPL mass and the severity of coronary atherosclerosis by comparing with other risk factors such as age, smoking, family history, hypertension, hyperuricemia, diabetes mellitus, total cholesterol, triglyceride, high density lipoprotein-cholesterol and body mass index. The subjects, 70 men presenting with symptoms of coronary artery disease, underwent coronary angiographic examination. Significant narrowness was defined as > or = 75%. Control group comprised 77 men who had annual health checks and showed no abnormal findings. Preheparin LPL mass in the stenosis group was lower than normal coronary group and also than the control group. Multivariate analysis showed that preheparin LPL mass had the highest t-value (-2.53) for the number of lesions among the risk factors listed above. These results suggest that low preheparin LPL mass may be deeply involved in the progression of coronary atherosclerosis.

Corticobasal degeneration: MR with histopathologic comparison.

The purpose of this study was to illustrate the MR findings of corticobasal degeneration and to compare those findings with pathologic specimens. MR findings of atrophy in the perirolandic gyri, atrophy of the basal ganglia, and T2 prolongation in the posterolateral putamen are useful evidence supporting the clinical diagnosis of corticobasal degeneration.

The evolution of cerebral blood flow in the developing brain: evaluation with iodine-123 iodoamphetamine SPECT and correlation with MR imaging.

BACKGROUND AND PURPOSE: Although it is well established that brain maturation correlates temporally with the functions the newborn or infant performs at various stages of development, the precise relationship between function and anatomic brain maturation remains unclear. The purpose of this study was to investigate the developmental changes of regional cerebral blood flow (rCBF) in infants and children using iodine-123 iodoamphetamine (123I-IMP) and single-photon emission computed tomography (SPECT). These findings were correlated with the MR imaging appearance of the brain and with known developmental changes. METHODS: Twenty-one 123I-IMP SPECT examinations of 17 patients, ranging in age from neonates to 2 years, were reviewed retrospectively. All children had had transient neurologic events in the neonatal period that did not significantly affect subsequent neuropsychological development. MR studies were performed in 12 of these patients and the MR findings were correlated with the SPECT results. RESULTS: SPECT studies showed a consistent pattern of evolving changes in 123I-IMP uptake, most likely reflecting evolution of rCBF. From the 34th postconceptional week until the end of the second month after term delivery, there was predominant uptake in the thalami, brain stem, and paleocerebellum, with relatively less cortical activity. Radionuclide uptake in both the perirolandic and occipital cortices was well seen around the 40th postconceptional week and increased rapidly thereafter, with a predominance of parietal activity. By 3 months, radionuclide uptake in the cerebellar hemispheres and parietofrontal cortices increased. Frontal and temporal activity increased by age 6 to 8 months. Uptake in the basal ganglia increased by 8 months. By the beginning of the second year, rCBF showed a similar topographic pattern to that in adults. CONCLUSION: The time course of the changes in 123I-IMP uptake in the developing brain as detected by SPECT is similar to that of myelination and most likely reflects an overall topologic maturational pattern of the brain.

Intracranial vascular stenosis and occlusion: MR angiographic findings.

PURPOSE: To investigate whether obtaining axial source images from three-dimensional Fourier transform (3DFT) time-of-flight MR angiography improves the detection of intracranial vascular stenosis and occlusion if added to maximum-intensity projection (MIP) images. METHODS: The angiograms of 103 patients who had MR angiography for evaluation of possible intracranial vascular disease were reviewed retrospectively in a quantitative and nonquantitative fashion. Diameters of vessels on MR angiograms were measured quantitatively by two reviewers using a magnifying loupe and compared with the results from conventional angiograms. Degrees of stenoocclusive disease were categorized into five classes; an artery with stenosis of 50% or greater was considered to be diseased. Another five observers also reviewed the MIP images with and without source images in a blinded fashion by means of nonquantitative visual inspection. RESULTS: In all, 23 stenoocclusive lesions of 50% or greater were available for review. In the quantitative analysis, with MIP images alone, 14 (78%) of 18 moderate and severe stenoses and four (80%) of five occlusions were identified correctly. The addition of the source images increased the sensitivity to 100% for moderate and severe stenoses and to 100% for occluded vessels. In the visual inspection study, however, no statistically significant differences were found between interpretations of MIP images alone and those of MIP images in combination with source images. CONCLUSION: In the quantitative study, interpretation of source images rather than MIP images reduced the tendency to overestimate stenosis seen with MR angiography and improved the sensitivity for detecting stenosis of 50% or greater. There was a discrepancy between the quantitative study and visual inspection. Experienced observers had a tendency to underestimate the degree of stenosis.

Six year observational cohort study of the effect of carbon disulphide on brain MRI in rayon manufacturing workers.

AIMS: To clarify whether the current occupational exposure limit (OEL) for carbon disulphide (CS2) is low enough to prevent the occurrence of adverse effects on the cerebrovascular system. METHODS: A total of 432 male workers exposed to CS2 and 402 male referent workers in 11 Japanese viscose rayon factories were studied at baseline; 750 of these were followed up. Brain MRI was performed at both baseline and follow up surveys. Changes in the number of hyperintense spots in T2 weighted images (HIS), which point to so-called "silent cerebral infarctions", were evaluated over six years. A total of 666 subjects (217 exposed, 125 ex-exposed, and 324 referent subjects) who twice received brain MRI were subjected to analysis. Mean duration of exposure to the end of the study was 19.6 years for the exposed workers. The geometric mean CS2 (ppm) and TTCA (mg/g creatinine) concentrations for the past six years were 4.9 and 1.6 for all exposed workers, 5.8 and 1.9 for spinning/refining workers, and 2.7 and 0.9 for other exposed workers, respectively. RESULTS: Exposed subjects showed a significantly higher risk for an increase in the number of HIS over six years. Odds ratios adjusted for possible confounders in the exposed and ex-exposed workers were 2.27 (95% CI 1.37 to 3.76) and 1.33 (95% CI 0.70 to 2.54), respectively. No exposure-response relations were observed in a number of analyses among the exposed workers. CONCLUSIONS: Exposure to CS2 under the current Japanese OEL, 10 ppm, might increase the number of HIS in brain MRI. However, results should be interpreted with caution.

Ischemic brain lesions in aged patients with dizziness.

OBJECTIVE: To compare neuro-otological test results in aged patients complaining of dizziness with their magnetic resonance imaging findings. DESIGN: The presence of lacunar infarcts of the hind-brain was used as a gold standard. SETTING: A department of otolaryngology in a regional general hospital. PATIENTS: All patients over 60 years old with dizziness during a period of 1 year 2 months, excluding those with central lesions of other than vascular origin (n=48). RESULT: Lacunar infarcts were found in 22 patients: the cerebellum for two patients, the brain stem for 17, and both regions for three. Patients with lesions of the cerebellum or the lower brain stem showed central vestibular abnormalities, whereas eight patients with only the upper brain-stem lacunae did not. A canal paresis was found in 12 of 20 patients with the brain-stem lacunae. Patients without lesions in the posterior fossa did not show significant abnormalities, indicating central disorders. CONCLUSION: This study documents a high prevalence of lacunar infarcts of the hindbrain in patients over 60 years old with dizziness, and it also demonstrates the difficulty in detecting small lesions of only the upper brain stem by neuro-otological tests. This calls attention to a differential diagnosis in aged patients with dizziness.

Functional recovery and regeneration of descending tracts in rats after spinal cord transection in infancy.

STUDY DESIGN: The functional recovery of rats that underwent spinal cord transection in infancy was evaluated by multimodal examination (functional tests, electrophysiologic evaluation, tract-tracing) to determine the basis for the recovery. OBJECTIVES: To determine whether the hind limb function in rats that underwent spinal cord transection in infancy is regained completely, which descending tracts regenerate after the transection, and whether the functional recovery is correlated with axonal reconnection. SUMMARY OF BACKGROUND DATA: It is widely accepted that a newborn rat recovers its hind limb function after spinal cord transection even without any specific treatments. This functional recovery might be attributed to possible regeneration of some descending pathways, although there is a counterargument that well-trained spinal cord reflexes may bring about functional compensation. METHODS: The thoracic spinal cord of infant rats was completely transected at Th10 when they were 2 weeks of age. Multimodal functional tests and electrophysiologic studies were performed 5 weeks later. Some recovered rats (i.e., those able to walk after the transection) underwent spinal cord retransection, with subsequent reevaluation of locomotion and muscle-evoked potentials. At 6 weeks after the initial transection, tract-tracing studies were performed in some animals. RESULTS: A motor performance score detected the functional differences between the control and the recovered rats. Muscle-evoked potentials of hind limbs after electrical stimulation to the brain were recorded in some of the recovered rats, but never in the unrecovered rats. Moreover, the muscle-evoked potentials of the recovered rats disappeared after spinal cord retransection that resulted in loss of voluntary movement. Morphologic studies in two rats provided evidence that reconnection of rubrospinal, vestibulospinal, and reticulospinal tracts had occurred, whereas corticospinal regeneration was not detected. CONCLUSIONS: It can be concluded that the hind limb function of rats that underwent spinal cord transection in infancy was partially regained; that axonal regeneration of the rubrospinal, vestibulospinal, or reticulospinal tracts was demonstrated, whereas the reconnection of the corticospinal tract was not observed; and that the axonal regeneration of these tracts is involved in the functional recovery.

The association of degeneration of the intervertebral disc with 5a/6a polymorphism in the promoter of the human matrix metalloproteinase-3 gene.

It has been suggested that matrix metalloproteinase-3 (MMP-3, stromelysin-1) has an important role in the degeneration of intervertebral discs (IVDs). A human MMP-3 promoter 5A/6A polymorphism was reported to be involved in the regulation of MMP-3 gene expression. We suggest that IVD degeneration is associated with 5A/6A polymorphism. We studied 54 young and 49 elderly Japanese subjects. Degeneration of the lumbar discs was graded using MRI in the younger group and by radiography in the elderly. 5A/6A polymorphism was determined by polymerase-chain reaction-based assays. We found that the 5A5A and 5A6A genotype in the elderly was associated with a significantly larger number of degenerative IVDs than the 6A6A (p < 0.05), but there was no significant difference in the young. In the elderly, the IVD degenerative scores were also distributed more highly in the 5A5A and 5A6A genotypes (p = 0.0029). Our findings indicate that the 5A allele is a possible risk factor for the acceleration of degenerative changes in the lumbar disc in the elderly.

Malignant schwannoma of the heart.

Primary cardiac tumor is an extremely rare disease entity. Only three cases of primary malignant cardiac schwannoma, the subject of this report, have been recorded in Japan. Recently, we encountered a case of malignant schwannoma in which retention of pericardial effusion was the first clinical finding. This case was a 30-year-old female, who had dyspnea at work, general fatigue, and fever. Striking cardiac expansion was seen, with a cardiothoracic ratio (CTR) of 69% on chest x-ray. Two-dimensional echocardiograms showed a large volume of pericardial effusion between the side wall of the left ventricle and the epicardium, and the presence of a parenchymatous tumor. An increase in tumor size was detected on chest computer tomography (CT) scan. Using a pump oxygenator, median sternotomy was performed to reach the epicardium. A pale yellow, soft tumor was seen in the left atrium near the left ventricle. Histologically, the patient was diagnosed as having a malignant schwannoma. We have reported a case of primary malignant schwannoma which was surmised to have arisen from the boundary between the atrium and the ventricle.

Sudden sensorineural hearing loss associated with slow blood flow of the vertebrobasilar system.

To determine the characteristics of sudden deafness associated with slow blood flow (SBF) within the vertebrobasilar arteries, we evaluated 57 patients with sudden deafness using magnetic resonance imaging (MRI). We detected SBF in 12 (21%) patients, predominantly men over 50 years of age. A second MRI performed in 5 patients 2 months after the onset of symptoms showed recovery of blood flow. All 12 patients complained of vertigo. Audiological and neurotologic tests suggested that hearing loss mainly involved the inner ear. Our findings suggest that unless central lesions are detected, headache, hypoesthesia of the external ear canal, and electronystagmographic abnormalities are signs of SBF. Because sudden deafness may recur in patients who have SBF, they should be monitored and treated to prevent recurrence.

Partial type of common atrioventricular canal defect associated with mitral stenosis.

We report a 63-year-old woman, with a partial type of common atrioventricular canal and mitral stenosis, who was hospitalized because of dyspnea on exertion. Two-dimensional echocardiogram showed an ostium primum atrial septal defect with two well-formed AV valves located at the same level. However, both anterior and posterior mitral leaflets were markedly thickened with a thickened subvalvular apparatus, and the commisures were fused. Echocardiographic measurements demonstrated a mitral valve area of 1.48 cm2 with mild mitral regurgitation. Cardiac catheterization demonstrated mild pulmonary artery hypertension with a large left to right shunt (72%) at the atrial level. The combination of the partial type of common atrioventricular canal and mitral stenosis is rare; only one similar case has been reported previously in the literature.

Usefulness of gradient-echo T2*-weighted MR imaging in evaluation of transorbital penetrating cerebral injury.

Transorbital penetrating cerebral injury can cause severe morbidity if not identified and treated. After the removal of the object and without the clinical information, even the chance of suspicion of penetrating cerebral injury might be missed in the first investigation. We report a case of transorbital penetrating cerebral injury caused by a metal rod and diagnosed by MRI including gradient-echo T2*-weighted imaging.

Volumetric and dimensional measurements of vestibular structures in the squirrel monkey.

Temporal bones of squirrel monkeys which were sectioned either in the routine horizontal plane or in the exact plane of lateral semicircular canal, were used for the volumetric and dimensional measurements. Endolymphatic volumes of utriculus, sacculus, lateral ampulla, lateral semicircular duct, and some related perilymphatic volumes were measured with the aid of a computer. The sizes of the duct-ampulla junction, ampulla-utriculus junction, duct-utriculus junction, etc. were also measured. The endolymphatic volume in the lateral ampulla was about 50% greater than that in the lateral semicircular duct. The endolymphatic volume involved in the rotation in the lateral canal plane was 2.188 mm3. Among those the utriculus was about half and the other half was the ampulla plus the duct. Furthermore, we measured the circumferences of the membranous semicircular ducts both in freshly dissected materials and in processed temporal bones. A statistically significant difference (p less than 0.01) was found between them. The actual tissue shrinkage factor was 9.2-9.3%.

Otoacoustic emission as an indicator in evaluating inner ear impairments.

Stimulated otoacoustic emissions (OAEs) were recorded from subjects with various kinds of sensorineural loss. The interaural difference in the value of the OAE pseudothreshold was significantly higher in unilateral inner ear impairments, in which there was a positive correlation between the interaural difference in the values of the psychoacoustic threshold and of the OAE pseudothreshold. There were no interaural differences of OAE in the cases of unilateral functional deafness. The measurement of OAE may serve as an indicator for evaluating sensorineural hearing losses.

Utricular and saccular volumetry in human temporal bones.

Using serially sectioned human temporal bones, endolymphatic volumes of utriculus and sacculus were measured with the aid of a computer. The mean of the utricular volume was 8.187 mm3, and the saccular volume, 2.096 mm3. The former was 3.9 X the latter. The surface area of the macula utriculi was 3.271 mm2, and the macula sacculi was 2.188 mm2. The former was 1.5 X the latter. The study using pathologic temporal bones (Meniere's disease, otosclerosis, and otitis media chronica) showed that the utricular volume could indeed increase, and the saccular membrane was found to be more fragile than the utricular membrane in those diseased conditions.

The squirrel monkey stabilimetry.

In order to characterize postural ataxia associated with peripheral vestibular lesions, we have developed a T-perch recording system suitable for squirrel monkeys (tree-living primates). This system includes strain gauges for detecting movement of the vertical shaft in the directions of anterior-posterior and left-right. Simultaneously we recorded electroencephalogram (EEG), vertical eye movement, electrocardiogram (ECG) and respiration (by pneumography). Representative Dynographic records (obtained during sleep) after unilateral and bilateral (two-staged) labyrinthectomy showed the frequent occurrence of phasic body movements: slow deviations to the lesion side and the frontward and subsequent quick rightings which occurred almost synchronously with the sleep becoming shallow (judged by EEG).

Further study of physical exercise and locomotor balance compensation after unilateral labyrinthectomy in squirrel monkeys.

The effect of physical exercise on compensation for locomotor asymmetry after unilateral labyrinthectomy was studied in squirrel monkeys. Five monkeys were assigned to the motor-driven rotating cage exercise, and another five, non-exercise control. Daily exercise (cumulative time of 2 1/2 hours) was given for three weeks preoperatively and continuously (daily) post-operatively. The average number of calendar days to attain the locomotor balance compensation was 20 days in the exercise group, and 35 days in the non-exercise control group. Statistical analysis showed the former compensated (according to the previously established criterion) significantly faster than the latter ( less than 0.05). Furthermore, faster reduction of gait deviation was found in the exercise group. Therefore, when physical exercise was given extensively and continuously, and locomotor balance function was measured by the squirrel monkey platform runway test (Igarashi, 1974), physical exercise application enhanced the locomotor equilibrium compensation.

Vestibular-visual conflict sickness in the squirrel monkey.

When combined vestibular and visual (optokinetic) stimuli were given to squirrel monkeys in a direction and phase mismatching sinusoidal mode (in yaw plane), five of six monkeys exhibited actual emesis during three repeated exposures on separate trial days. Two animals vomited on two trial days and three animals, on one day. The incidence took place in 38.9% of the total trial days. When the identical vestibular and visual stimuli were given individually, the effect was negligible, thus confirming each stimulus magnitude was not stressful enough to produce emesis when used separately.

Slow blood flow of the vertebrobasilar system in patients with dizziness and vertigo.

We evaluated 102 patients with dizziness or vertigo who were 50 years of age and over, using magnetic resonance imaging (MRI). Slow blood flow (SBF) in the vertebrobasilar system was detected in 36 patients (35%). The patients with SBF experienced dizziness or vertigo for a longer period than those without SBF. The apogeotrophic type of direction-changing nystagmus was observed in 10 of 36 patients with SBF. No significant differences were found between patients with and without SBF with other neurotological tests. Because MRI can detect both infarcts in the hind-brain and SBF in the vertebral and basilar arteries it is recommended for evaluation of vascular disorders in older patients with vestibular symptoms.

MR angiography of intracranial aneurysms: a comparison of 0.5 T and 1.5 T.

The objective of this paper is to compare the diagnostic efficacy of 3 DFT time-of-flight MR angiography (MRA) at middle-field-strength and high-field-strength in diagnosis of intracranial aneurysms. Thirty-one patients, including 26 patients with angiographically confirmed intracranial aneurysms (n = 28), underwent MRA at 0.5 and 1.5 T. Images were interpreted by six trained observers who were blinded to diagnosis. Twelve projections of MRA of the circle of Willis, by maximum-intensity projection algorithm, were reviewed using continuous confidence-judgement scales. It was found that MRA at 1.5 T was more sensitive than that at 0.5 T in detection of aneurysms. The sensitivity of six observers ranged between 50 and 64% (mean 56%) at 0.5 T, and between 61 and 86 86% (mean 75%) at 1.5 T. In the smaller aneurysms less than 5 mm, the differences between the units became greater. The sensitivity for small aneurysms ranged from 23 to 54% (mean 32%) at 0.5 T, and from 31 to 69% (mean 58%) at 1.5 T. Our conclusion was that high field strength confers higher accuracy in the detection of intracranial aneurysms with MRA with current-generation MR imagers.