InP nanowire light-emitting diodes with different pn-junction structures

We report on the characterization of wurtzite (WZ) InP nanowire (NW) light-emitting diodes (LEDs) with different pn junctions (axial and radial). The series resistance tended to be smaller in the NW-LED using core-shell InP NWs with a radial pn junction than in the NW-LED using InP NWs with an axial pn junction, indicating that radial pn junctions are more suitable for current injection. The electroluminescence (EL) properties of both NW LEDs revealed that the EL had three peaks originating from the zinc-blende (ZB) phase, WZ phase, and ZB/WZ heterojunction. Transmission electron microscopy showed that the dominant EL in the radial pn junction originated from the ZB/WZ interface across the stacking faults.

Novel condylar repositioning method for 3D-printed models

Background

Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation.

Methods

Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models.

Results

This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases.

Conclusions

We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.

Clinical and Microangiographic Studies on Rupture of the E.P.L. Tendon after Distal Radial Fractures

The authors have treated 14 cases of spontaneous rupture of extensor pollicis longus tendon after fractures of the distal end of the radius, most of which were undisplaced or only slightly displaced. A microvascular study on five cadavers revealed that this tendon is subject to mechanical bending and attrition, has no mesotenon and has a poorly vascularised portion about 5 mm in length, which may be a cause of spontaneous rupture of the tendon.

Dissociable mechanisms of attentional control within the human prefrontal cortex

Neuropsychological tests that require shifting an attentional set, such as the Wisconsin Card Sorting Test, are sensitive to frontal lobe damage. Although little information is available for humans, an animal experiment suggested that different regions of the prefrontal cortex may contribute to set shifting behavior at different levels of processing. Behavioral studies also suggest that set shifting trials are more time consuming than non-set shifting trials (i.e. switch cost) and that this may be underpinned by differences at the neural level. We determined whether there were differential neural responses associated with two different levels of shifting behavior, that of reversal of stimulus-response associations within a perceptual dimension or that of shifting an attentional set between different perceptual dimensions. Neural activity in the antero-dorsal prefrontal cortex increased only in attentional set shifting, in which switch costs were significant. Activity in the postero-ventral prefrontal cortex increased not only in set shifting but also in reversing stimulus-response associations, in which switch costs were absent. We conclude that these distinct regions in the human prefrontal cortex provide different levels of attention control in response selection. Thus, the antero-dorsal prefrontal cortex may be critical for higher order control of attention, i.e. attentional set shifting, whereas the postero-ventral area may be related to a lower level of shift, i.e. reorganizing stimulus-response associations.

Comparison of the pattern of atrophy of the corpus callosum in frontotemporal dementia, progressive supranuclear palsy, and Alzheimer's disease

OBJECTIVES

The loss of the neurons in layer 3, one of the groups of cortical neurons most vulnerable in various degenerative brain diseases, results in axonal degeneration leading to atrophy of the corpus callosum. Previous studies showed callosal atrophy in three degenerative dementias: frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), and Alzheimer's disease (AD). However, it is unclear whether a characteristic pattern of atrophy is present in each. The objective of this study was to investigate whether the pattern of the callosal atrophy was different among patients with FTD, PSP, or early onset AD.

METHODS

Eleven patients with FTD, nine patients with PSP, 16 patients with early onset AD, and 23 normal controls, all age and sex matched, were studied using MRI. The ratios of midsagittal corpus callosum areas to the midline internal skull surface area on T1 weighted images were analyzed. The corpus callosum was divided into quarters: the anterior, middle-anterior, middle-posterior, and posterior portions.

RESULTS

Compared with controls, all three patient groups had significantly decreased total callosal/skull area ratio. An analysis of covariance adjusted for the total callosal area/skull area ratio showed that the anterior quarter callosal/skull area ratio in FTD, the middle-anterior quarter area ratio in PSP, and the posterior quarter area ratio in AD were significantly smaller than those in the other three groups.

CONCLUSION

Although atrophy of the corpus callosum is not specific to any degenerative dementia, the patterns of the atrophy are different among patients with FTD, PSP, or early onset AD. Differential patterns of callosal atrophy might reflect characteristic patterns of neocortical involvement in each degenerative dementia.

Glucose metabolism in the rat frontal cortex recovered without the recovery of choline acetyltransferase activity after lesioning of the nucleus basalis magnocellularis

We measured the cerebral metabolic rate of glucose (CMRglc) by using positron emission tomography (PET) with [18F]fluorodeoxyglucose (FDG) and the choline acetyltransferase (ChAT) activity at 3 days and 3 months after destruction of the nucleus basalis magnocellularis (NBM). Although the frontal ChAT activity remained 20% lower than that of controls even at 3 months post-lesioning, the frontal CMRglc, which was reduced by 40% at 3 days, returned to normal at 3 months, namely CMRglc recovered with time without the recovery of ChAT activity with time. Since glucose metabolism reflects mainly presynaptic neuronal activity, we speculate that presynaptic rearrangement may have some relation to the recovery of CMRglc.

The effect of sequential lesioning in the basal forebrain on cerebral cortical glucose metabolism in rats. An animal positron emission tomography study

We studied the effect of the cortical projection from the basal forebrain on the cerebral cortical metabolism using positron emission tomography (PET) with [(18)F] fluorodeoxyglucose. Unilateral damage of the nucleus basalis magnocellularis (NBM) did not cause a permanent reduction of cortical metabolism: recovery was observed 4 weeks after the operation. Destruction of the contralateral side after recovery from unilateral damage produced persistent bilateral suppression of glucose metabolism, with partial recovery. We speculate that recovery from the unilateral NBM lesions is partly ascribable to the cholinergic projection from the contralateral NBM, and partly due to non-cholinergic systems, and conclude that bilateral damage might be responsible for persistent cortical glucose metabolism suppression.

Transient neural activity in the medial superior frontal gyrus and precuneus time locked with attention shift between object features

To investigate the contribution of the superior frontal gyrus and precuneus to the cognitive process of attention set shift, we examined the correlation between change in neural activity in these areas and the timing of attention set shift using event-related functional magnetic resonance imaging. Seven subjects underwent a card-sorting task in which they matched a test card to one of two target cards according to color or shape. The subjects had to determine the correct category based only on feedback and shift the sorting principle when the feedback changed from "correct" to "incorrect." Transient increase of neural activity time locked with attention shift phases was detected in the medial superior frontal gyrus (the rostral part of the supplementary motor area) and precuneus. During the control task, in which the feedback and the motor responses were preserved without any attention shift, this type of change in neural activity was not observed. Our findings indicate that increase in neural activity in these brain areas may be closely related to attention set shift between object features and suggest that these areas may play a role in the shifting of cognitive sets.

Cerebral glucose metabolism in unilateral entorhinal cortex-lesioned rats: an animal PET study

To evaluate the effect of entorhinal cortical lesion on cerebral cortical function, we studied cerebral glucose utilization (CMRGlc) using a high resolution PET scanner after quinolinic acid lesion of the unilateral entorhinal cortex in rats. [18F]Fluorodeoxyglucose PET was performed at 4 days and 4 weeks after surgery, and CMRGlc in the bilateral frontal, parietal and temporal regions were analyzed. At 4 days, the entorhinal lesion induced a 12-15% decrease in CMRGlc of frontal, parietal and temporal regions ipsilateral to the lesion. The hypometabolism continued at 4 weeks in the temporal region. These findings suggest that entorhinal lesion induces cerebral cortical hypometabolism, which implies a pathogenetic role of entorhinal area on the cortical hypometabolism in Alzheimer's disease.

Mechanisms underlying gait disturbance in Parkinson's disease: a single photon emission computed tomography study

Single photon emission computed tomography was used to evaluate regional cerebral blood flow changes during gait on a treadmill in 10 patients with Parkinson's disease and 10 age-matched controls. The subjects were injected with [99mTc]hexamethyl-propyleneamine oxime twice: while walking on the treadmill, which moved at a steady speed, and while lying on a bed with their eyes open. On the treadmill, all subjects walked at the same speed with their preferred stride length. The patients showed typical hypokinetic gait with higher cadence and smaller stride length than the controls. In the controls, a gait-induced increase in brain activity was observed in the medial and lateral premotor areas, primary sensorimotor areas, anterior cingulate contex, superior parietal cortex, visual cortex, dorsal brainstem, basal ganglia and cerebellum. The Parkinson's disease patients revealed relative underactivation in the left medial frontal area, right precuneus and left cerebellar hemisphere, whereas they showed relative overactivity in the left temporal cortex, right insula, left cingulate cortex and cerebellar vermis. This is the first experimental study showing that the dorsal brainstem, which corresponds to the brainstem locomotor region in experimental animals, is active during human bipedal gait. The reduced brain activity in the medial frontal motor areas is a basic abnormality in motor performance in Parkinson's disease. The underactivity in the left cerebellar hemisphere, in contrast to the overactivity in the vermis, could be associated with a loss of lateral gravity shift in parkinsonian gait.

Enhanced lateral premotor activity during paradoxical gait in Parkinson's disease

Parkinson's disease (PD) patients often show marked improvement of hypokinetic gait when exposed to special stimuli. To investigate physiological mechanisms underlying this "paradoxical gait" induced by visual cues in PD patients, we examined regional cerebral blood flow changes during gait on a treadmill guided by two different visual cues, the lines oriented transversely to the direction of walk (TL) and the lines parallel to it (PL). Ten PD patients and 10 age-matched controls received injections of 99mTc-hexamethylpropyleneamine oxime twice, once during each walking condition. Brain perfusion images were obtained by single-photon emission computed tomography. When affected by TL, PD patients showed marked improvement of gait parameters, mainly reduction of cadence. In regional cerebral blood flow analysis, when TL was compared with PL, both groups had common activation in the posterior parietal cortex and cerebellar hemispheres. Especially in the right lateral premotor cortex, PD patients showed enhanced activation induced by TL to a significantly greater degree than the controls. The present study indicates that the network dedicated to visuomotor control, particularly the lateral premotor cortex, plays an important role in the development of the paradoxical gait induced by special visual stimuli in PD patients.

Selective cerebral hematocrit decrease in the centrum semiovale after carotid artery occlusion: a PET study

The centrum semiovale may be susceptible to hypoperfusion as a result of carotid artery occlusion. Recent studies suggest that the cerebral hematocrit decreases with diminished cerebral perfusion pressure. To investigate whether the effect of carotid artery occlusion on the hematocrit in the centrum semiovale is different from that in the cerebral cortex, seven patients with unilateral carotid artery occlusion were studied with positron emission tomography. The distributions of the red blood cell and plasma volumes were assessed using carbon monoxide labeled with oxygen 15 and human serum albumin-dithiosemicarbazone tracers labeled with copper 62, respectively. The CBF and CMRO2 were also measured with the (15)O steady-state technique. The calculated values for the hematocrit in the centrum semiovale ipsilateral to the arterial occlusion were significantly decreased compared with those in any of the other regions examined (the overlying cortical region and the contralateral cortex and centrum semiovale). This decrease in hematocrit, which resulted from a more pronounced increase in plasma volume than in red blood cell volume, was associated with a decrease in CBF and an increase in the oxygen extraction fraction. Hemodynamic disturbance caused by carotid artery occlusion may induce selective decrease of hematocrit limited to the centrum semiovale.

Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine

STUDY DESIGN

This is a retrospective study of the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament in the cervical spine.

OBJECTIVES

To determine the morphologic limitations of the posterior approach in the management of ossification of the posterior longitudinal ligament.

SUMMARY OF BACKGROUND DATA

Thirty-eight patients who underwent laminoplasty by midsagittal splitting for ossification of the posterior longitudinal ligament were reviewed. Fifteen patients were included in the noncontact group, in which the spinal cord was free of the ossified lesion after posterior decompression. Twenty-three patients were included in the contact group, in which the spinal cord was not free of the ossified lesion even after posterior decompression.

METHODS

The preoperative sagittal alignment of the cervical spine and preoperative maximal thickness of ossification were compared between the two groups. In addition, the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament were investigated.

RESULTS

The following factors were found to contribute significantly to contact between the spinal cord and ossification of the posterior longitudinal ligament after posterior decompression: 1) lordosis of less than 10 degrees or kyphosis in the preoperative sagittal alignment, and 2) preoperative maximal thickness of ossification of more than 7 mm.

CONCLUSIONS

Patients who exhibit significant risk factors for continued contact of the spinal cord should be morphologically considered for anterior decompression.

Issues in measuring glucose metabolism of rat brain using PET: the effect of harderian glands on the frontal lobe

We estimated the effect of the Harderian gland (an orbital gland of land vertebrates) on the measurement of cerebral metabolic rate of glucose (CMRGIc) of the rat brain using positron emission tomography (PET) for animal use. The Harderian gland had the high accumulation of 18-F labeled deoxyglucose (FDG) after intravenous injection. By placing the large regions of interest (ROI) (twice the full width at half maximum in diameter), the CMRGIc in the frontal region was slightly higher compared with the CMRGIc after Harderian gland resection, but the parietal and occipital regions and the cerebellum had the similar level of CMRGIc before and after Harderian gland resection. Therefore the Harderian gland has a slight effect on the frontal lobe CMRGIc, but such overestimation can be within the permissible range for PET study of rat brains.

Neural activity during attention shifts between object features

To investigate the neural mechanisms involved in shifting attention we used positron emission tomography to examine regional cerebral blood flow (rCBF) during a task that demands shifting attention between color and shape. Significant activation was observed in the right dorsal prefrontal cortex and parieto-occipital cortex at all frequencies of attention shifts. The frequency of shifts between categories correlated significantly with rCBF in the rostral part of the supplementary motor area and the left precuneus, whereas the number of successive correct responses correlated with rCBF in the orbitofrontal cortex and the caudate nucleus. This study suggests that several prefrontal regions may participate in the processes of shifting attention in different ways.

Atrophy of the corpus callosum, cortical hypometabolism, and cognitive impairment in corticobasal degeneration

OBJECTIVE

To investigate whether atrophy of the corpus callosum is associated with cognitive impairment and cerebral cortical hypometabolism in corticobasal degeneration.

DESIGN

Prospective clinicoradiological correlation with magnetic resonance imaging and positron emission tomography.

SETTING

A university hospital.

PATIENTS

Eight right-handed patients with clinically diagnosed corticobasal degeneration (mean+/-SD age, 64+/-8 years).

MAIN OUTCOME MEASURES

Midsagittal corpus callosum area-skull area ratio (on T1-weighted magnetic resonance images), the sum of the scaled scores of the 6 subtests on the Wechsler Adult Intelligence Scale-Revised (Digit Span, Arithmetic, Picture Arrangement, Object Assembly, Block Design, and Digit Symbol), and cerebral metabolic rate of glucose (measured with positron emission tomography by using fludeoxyglucose F 18 as a tracer).

RESULTS

Compared with 36 age-matched right-handed control subjects, the patients had significantly decreased callosal area-skull area ratio. The reduction in this ratio was greatest in the middle half of the corpus callosum. The atrophy of the corpus callosum was accompanied by a decreased mean cortical glucose metabolic rate with hemispheric asymmetry and a decrease in the sum of the scaled subtest scores of the Wechsler Adult Intelligence Scale-Revised.

CONCLUSIONS

Atrophy of the corpus callosum with middle predominance is present in corticobasal degeneration, and this atrophy is associated with cognitive impairment and cerebral cortical hypometabolism with hemispheric asymmetry. Atrophy of the corpus callosum might reflect the severity of the disconnection between cortical regions, and this may be an important factor in the development of cerebral cortical dysfunction in corticobasal degeneration.

Cerebral hematocrit decreases with hemodynamic compromise in carotid artery occlusion: a PET study

BACKGROUND AND PURPOSE

This study investigated whether in patients with internal carotid artery occlusion the regional cerebral hematocrit correlates with cerebral hemodynamics or metabolic state and, if so, how the regional cerebral hematocrit changes in the hemodynamically compromised region.

METHODS

We used positron emission tomography to study seven patients with unilateral internal carotid artery occlusion and no cortical infarction in the chronic stage. The distributions of red blood cell and plasma volumes were assessed using oxygen-15-labeled carbon monoxide and copper-62-labeled human serum albumin-dithiosemicarbazone tracers, respectively. The calculated hematocrit value was compared with the hemodynamic and metabolic parameters measured with the oxygen-15 steady-state technique.

RESULTS

In the cerebral cortex, the value of the cerebral hematocrit varied but was correlated with the hemodynamic and metabolic status. Stepwise regression analysis revealed that the large vessel hematocrit, the cerebral metabolic rate of oxygen, and the cerebral blood flow or the oxygen extraction fraction accounted for a significant proportion of variance of the cerebral hematocrit. The oxygen extraction fraction and the cerebral metabolic rate of oxygen negatively correlated with the cerebral hematocrit, whereas the cerebral blood flow correlated positively: patients with reduced blood supply relative to metabolic demand (decreased blood flow with increased oxygen extraction fraction) showed low hematocrit values.

CONCLUSIONS

In carotid artery occlusion in the chronic stage, regional cerebral hematocrit may vary according to cerebral hemodynamics and metabolic status. Regional cerebral hematocrit may decrease with hemodynamic compromise unless oxygen metabolism concomitantly decreases.

Effect of nicardipine on cerebral blood flow in hypertensive patients with internal carotid artery occlusion: a PET study

PURPOSE

The objective of this study was to elucidate the effect of intravenous administration of nicardipine on the cerebral blood flow of hypertensive patients with internal carotid artery occlusion (ICAO).

PATIENTS AND METHODS

Six patients with ICAO and 10 normal individuals were examined by positron emission tomography. The cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen, oxygen extraction fraction (OEF) and CBF/CBV ratio were evaluated for each vascular territory and each hemisphere, and the interhemispheric asymmetry index of each parameter was also calculated. Nicardipine was administered intravenously to each patient, and the changes in CBF (DeltaCBF%) and in blood pressure (DeltaBP) were examined.

RESULTS

After the administration of nicardipine, the CBF was significantly increased in the patient hemisphere and was unchanged in the occluded hemisphere. Stepwise regression analysis disclosed that the DeltaBP and asymmetry index of OEF were significantly correlated with the DeltaCBF% in the occluded hemisphere.

CONCLUSIONS

These results suggest that CBF is unchanged or increased in ICAO patients after nicardipine administration, but that excessive reduction of blood pressure may lead to CBF decrease in the patients with marked hemodynamic imbalance between the occluded and patent hemispheres. These results suggest that it is advisable not to reduce blood pressure excessively in these patients in the treatment of perioperative or acute hypertension with calcium antagonist.

Age-related changes in cerebral blood flow activation during a Card Sorting Test

To determine the age-related changes in the neural processing involved in the Modified Card Sorting Test (MCST), we measured cerebral blood flow (CBF) during performance of the MCST and of the number-matching task in young and elderly subjects using positron emission tomography. Compared with that during the number-matching task, CBF during the MCST was increased in the left dorsolateral prefrontal cortex (DLPFC), left inferior parietal lobule, and left striate and prestriate cortices in both age groups. However, CBF activation in these areas was significantly lower in the elderly subjects than the young subjects. Furthermore, CBF activation was reduced in the left DLPFC, right parahippocampal gyrus, and prestriate cortex in proportion to the increase in the number of perseverative errors with aging. These results suggest that the impaired MCST performance in elderly subjects may be due, in part, to dysfunction of the network involving certain cortical areas such as the prefrontal and parahippocampal cortices, although the essential neural circuits for MCST performance were still preserved even in the elderly subjects.

Atrophy of the corpus callosum, cognitive impairment, and cortical hypometabolism in progressive supranuclear palsy

Recent studies disclosed neurofibrillary degeneration in layer 3 of the association cortex in patients with progressive supranuclear palsy. This lesion may be associated with corpus callosum atrophy and may impair the function of cortical regions indispensable for complex cognitive activity. To investigate whether corpus callosum atrophy is associated with cognitive impairment and cerebral cortical hypometabolism, we studied 10 patients with progressive supranuclear palsy using magnetic resonance imaging and positron emission tomography with fluorodeoxyglucose as a tracer. Compared with 23 age-matched control subjects, the patients had significantly decreased callosal area-skull area ratios, with anterior predominance of the degree of atrophy. The corpus callosum atrophy was accompanied by a decreased mean cortical glucose metabolic rate, predominantly in the frontal region of the cortex, and poor performance on the picture arrangement subtest of the Wechsler Adult Intelligence Scale and the verbal fluency task. We conclude that corpus callosum atrophy with anterior predominance is present in progressive supranuclear palsy, and that this atrophy is associated with cognitive impairment and cerebral cortical hypometabolism, especially in the frontal cortical region. Corpus callosum atrophy may reflect the pathological changes in the cerebral cortex, accentuated in the frontal region, that contribute to the development of frontal lobe dysfunction in this disease.

Atrophy of the corpus callosum associated with cognitive impairment and widespread cortical hypometabolism in carotid artery occlusive disease

OBJECTIVE

To investigate whether atrophy of the corpus callosum is associated with cognitive impairment and widespread cerebral cortical hypometabolism in carotid artery occlusive disease.

PATIENTS

Twelve patients with unilateral internal carotid artery occlusive disease (1 with severe stenosis and 11 with occlusion) and no cortical infarction in the chronic stage (mean +/- SD age, 64 +/- 5 years).

MAIN OUTCOME MEASURES

Midsagittal corpus callosum area-skull area ratio (on T1-weighted magnetic resonance images), the sum of the scaled scores of the 6 subtests on the Wechsler Adult Intelligence Scale-Revised (Digit Span, Arithmetic, Picture Arrangement, Object Assembly, Block Design, and Digit Symbol), and cerebral metabolic rate of oxygen (measured with position emission tomography by using the oxygen 15 steady-state technique).

RESULTS

The degree of cognitive impairment varied but was strongly correlated with the severity of callosal atrophy (r = 0.92, P < .001). Patients with callosal atrophy and cognitive decline also showed decreased oxygen consumption in the bilateral cerebral cortices. Stepwise regression analysis revealed that the severity of white matter lesions, especially in the centrum semiovale, and that of cortical atrophy in the hemisphere with arterial disease were 2 important factors for callosal atrophy.

CONCLUSIONS

Callosal atrophy is associated with cognitive impairment and widespread cerebral cortical hypometabolism in carotid artery occlusive disease without cortical infarction. Callosal atrophy might reflect the severity of the disconnection between cortical regions, and this may be an important factor in the development of cognitive impairment with widespread cortical hypometabolism in carotid artery occlusive disease without large cortical lesions.

Cerebral oxygen and glucose metabolism in glycogen storage disease with normal acid maltase: case report

A 26-year-old male with cardiomyopathy, cervical muscle weakness and mental retardation was diagnosed as having glycogen storage disease with normal acid maltase on the basis of his clinical, pathological and biochemical findings. Positron emission tomography showed that cerebral oxygen metabolism was normal, while cerebral glucose metabolism was decreased in the cerebral cortexes. The decrease of the glucose metabolic rate may reflect an abnormality of cerebral glucose metabolism in this disorder and may be related to mental retardation, which is one of the characteristic symptoms.

A serine protease zymogen in insect plasma. Purification and activation by microbial cell wall components

A protease zymogen present in the plasma fraction of the hemolymph of silkworm, Bombyx mori, was purified to homogeneity as judged by SDS/PAGE and IEF/PAGE. An activating system for the zymogen was also isolated from the plasma fraction and was shown to be triggered by zymosan (yeast cell wall polysaccharide containing beta-1,3-glucan) or peptidoglycan. Using this system, the purified zymogen was activated and the active enzyme was purified to homogeneity. The physiological function of the zymogen or its active form is not yet known, but the active form was shown to have narrower substrate specificity than trypsin. Among 33 peptide derivatives examined, Boc-Gln-Arg-Arg-NH-Mec and Boc-Val-Pro-Arg-NH-Mec (Boc = tert-butoxycarbonyl, NH-Mec = 4-methylcoumaryl-7-amide) were the best and the second best substrates, respectively. The purified zymogen was determined to be a 39-kDa protein consisting of a single polypeptide. The active form of the zymogen was labeled with [3H]diisopropylfluorophosphate and was completely inactivated by (p-amidinophenyl)methanesulfonyl fluoride. The molecular mass of the [3H]-labeled enzyme was determined to be 38 kDa in SDS/PAGE under reducing conditions. These results indicate that the 39-kDa protein purified in the present study is a zymogen of a serine-type protease and that the activation of the zymogen occurs by limited proteolysis.

Sarcolemmal indentation in cardiomyopathy with mental retardation and vacuolar myopathy

Muscle biopsies from three patients with cardiomyopathy, mental retardation and increased serum creatine kinase levels revealed scattered fibers with tiny intracytoplasmic vacuoles containing basophilic and acid phosphatase-positive material and slightly increased amounts of PAS-positive granules. These findings are consistent with those seen in the so-called lysosomal glycogen storage disease with normal acid maltase. In addition to the vacuoles, there were occasional folds or indentations in the sarcolemma which were connected to the membrane enclosing the vacuoles. These membranes were well demonstrated histochemically by the nonspecific esterase and acetylcholinesterase stains. On electron microscopy, most of the vacuoles were bounded by membranes with basal lamina. The vacuolar membrane stained positively with antibodies raised to dystrophin, dystrophin-associated glycoproteins, laminin and type 4 collagen, and it was identical to the sarcolemma and its basal lamina. Therefore, the membrane abnormality which causes sarcolemmal folding is probably critical to understanding the pathomechanism of this disease.

[Cerebral blood flow and metabolism in Lafora disease]

An 18-year-old male manifesting intellectual deterioration and negative myoclonus was diagnosed as Lafora disease by the demonstration of Lafora bodies in the skin and muscle biopsy. The cortical evoked potential to electric stimulation of the median nerve at wrist showed the giant SEP, suggesting hyperexcitability of the sensory motor cortex. Cerebral blood flow, and cerebral glucose and oxygen metabolism were investigated by positron emission tomography (PET) in order to clarify the pathophysiological process in Lafora disease. The result showed diffusely decreased cortical glucose metabolic rate and cerebral blood flow, and moderately lowered oxygen metabolic rate. There was no increase in blood flow or glucose and oxygen metabolism in the sensorimotor cortex in spite of the presence of giant SEP. The ratio of the glucose to oxygen metabolism was not different from the mean value obtained from nine normal subjects. Based on these findings and review of the literature, it is unlikely that there is a significant deficit in cortical energy metabolism in patients with Lafora disease and it would be less plausible to have some enzymatic deficits in glucose metabolic process.

[A case of glycogen storage disease with normal acid maltase accompanied with the abnormal platelet function]

Glycogen storage disease with normal acid maltase first reported by Danon et al. was characterized clinically by mental retardation, cardiomyopathy, and proximal myopathy. Since the first report, 17 patients have been reported including 5 patients from Japan. In this paper we described a 26-year-old man who had dilatated cardiomyopathy with a pacemaker implanted at age 22 years. He was admitted to our hospital complaining of easy fatigability in February 1992. Neurological findings showed that he had mental retardation. Serum CK, GOT, GPT and aldolase levels were elevated. Histopathological study of biopsied skeletal muscle showed intracytoplasmic vacuoles with increased acid phosphatase and slightly increased PAS positive material. Electron microscopic study revealed numerous glycogenosomes (autophagic vacuoles containing glycogen). These pathological findings were similar to acid maltase deficiency, but activities of carbohydrate metabolic enzyme including acid maltase activity were normal in the biopsied muscle. From these results, he was diagnosed as having glycogen storage disease with normal acid maltase. We also found abnormal platelet function and glycogen accumulation in the platelets, which have not been previously described. The disease is probably a systemic disorder affecting not only skeletal and cardiac muscles, but platelets.

Regeneration of perineurium after nerve injury and autografting. An experimental study

Regeneration of the perineurium after crush injury to the rat sciatic nerve and after autografting was studied in an experimental model. After injury, fibroblast-like cells formed compartments inside the funiculus which gradually acquired the characteristics of the perineurial cell. After grafting, the pattern of perineural regeneration depended on the degree of Schwann cell damage. In the graft and distal nerve trunk the epineurium degenerated and disappeared and new perineural tissue was formed by endoneurial fibroblasts from the inside of the funiculus. At the suture line, fibroblasts encircled the regenerating axons and the Schwann cells to form new compartments resulting in a large number of minifasciles of regenerating nerve. The function of the perineurium as a diffusion barrier was restored satisfactorily in the crushed nerve, although there was no satisfactory repair at 30 weeks after nerve grafting.

Simultaneous flexion of the thumb and index finger after a fracture of the first metacarpal bone : A case report

We report a case in which simultaneous flexion of the thumb and index finger occurred after a fracture of the 1st metacarpal bone. This was demonstrated to be due to a fibrous adhesion around an anomalous slip between the tendons of flexor pollicis longus and flexor digitorum profundus indicis.

The Steffee variable screw placement system using different methods of bone grafting

Two groups of patients with diseased lumbar spines treated by the Steffee variable screw placement system were studied, in order to compare concomitant posterolateral fusion and posterior lumbar interbody fusion. The use of posterolateral fusion resulted in less invasiveness than posterior lumbar interbody fusion, with regard to operating time and blood loss. With the posterolateral fusion method, correction of olisthesis or kyphotic deformity, if attained at all, was difficult to maintain. Posterior lumbar interbody fusion produced better correction and maintenance, even in osteoporotic cases. Bone union was achieved at an average of 11 months in only 60% of the posterolateral fusion group, whereas it was complete within a significantly shorter period (average; 6 months) in 91% of the posterior lumbar interbody fusion group. Breakage or loosening of screws occurred in 14% of the posterolateral fusion group. Deep wound infection and adhesive arachnoiditis, which were never seen in the posterolateral fusion group, developed in 3% of the posterior lumbar interbody fusion group. Posterior lumbar interbody fusion is considered to be a better method of bone grafting than posterolateral fusion, when used with the Steffee variable screw placement system.

[A preliminary study on the morphological changes of the microvasculature following the peripheral nerve autografting]

The microvasculature of peripheral nerve following autografting was studied by scanning electron microscopy. The newly-formed capillaries was also examined by transmission electron microscopy. Capillaries of a fascicle were divided into an extrafascicular vascular plexus and an intrafascicular capillary bed; the former capillaries formed networks, while the latter capillaries ran longitudinally and formed slightly spiral curve. Normal intrafascicular capillaries had tight junctions, a continuous basement membrane and pericytes. On the suture line, capillaries of the graft and those of the host were connected by newly developed sinusoidal capillaries, which were formed at the extrafacicular region earlier than at the intrafascicular region. Newly developed sinusoidal capillaries were transformed into glomerulus-like capillaries and formed fine networks. These networks exhibited a normal capillary architecture after reconstruction. The endothelium of newly-formed capillaries showed a discontinuous basement membrane at the early stage of regeneration. An intrafascicular capillary bed was present in the middle part of the graft.

An experimental study of nerve regeneration through chemically treated allografts

We carried out experiments in rabbits to determine whether treating nerve transplants with gradually increasing concentrations of ethanol, ether and ficin would inhibit the graft-host immune reaction to the allograft. After treatment with ethanol, the basal laminar scaffold of the Schwann cell remained intact and there was satisfactory axonal regeneration. The results after additional treatment with ether or ficin did not achieve such good results. Preservation of the basal lamina is considered to be the essential factor in allowing neural regeneration in these circumstances.

Clinical and microangiographic studies on rupture of the E.P.L. tendon after distal radial fractures

The authors have treated 14 cases of spontaneous rupture of extensor pollicis longus tendon after fractures of the distal end of the radius, most of which were undisplaced or only slightly displaced. A microvascular study on five cadavers revealed that this tendon is subject to mechanical bending and attrition, has no mesotenon and has a poorly vascularised portion about 5 mm in length, which may be a cause of spontaneous rupture of the tendon.

Analysis of cervical instability resulting from laminectomies for removal of spinal cord tumor

Thirty-four patients with cervical cord tumor were followed in order to investigate the incidence of postoperative deformity or instability after laminectomies. Seven cases (20%) presented cervical instability, including three cases that required spinal fusion. Analysis of these cases revealed the identification of some risk factors that are involved in the pathogenetic mechanism of cervical instability, which are: age at operation, preoperative curvature in neutral position, number of removed laminas, C2 laminectomy, and destruction of facet joints. The number of these risk factors present in each case was shown to be directly related to the incidence of cervical instability. Patients who had not developed instability demonstrated 1.2 factors on average, while patients who had developed instability showed a mean of 2.5 factors. Patients who had additionally required spinal fusion presented 3 risk factors, including C2 laminectomy and destruction of facet joints.

Evaluation of sensibility after sensory reconstruction of the thumb

We have studied the restoration of sensation in 24 patients after operations involving the digital nerves of the thumb. These comprised 10 neurorrhaphies, two nerve graftings, five replantations, one toe-to-thumb transfer and six neurovascular island flaps. The average follow-up period was 46 months. Greater sensitivity was found in the moving two-point discrimination (2PD) test than in the static 2PD test. The results of the Semmes-Weinstein test showed good correlation with the static 2PD test. Porter's letter test showed correlations with both 2PD tests, and the pulp-writing test showed good correlation with the moving 2PD test. The neurorrhaphy cases had the best results using the static 2PD and Semmes-Weinstein test, and had good restoration of sensation; the replantation cases were next best. After neurovascular island flaps, patients exhibited hypersensitivity, double sensation and distorted images on the pulp-writing test. Using this same test the nerve grafting cases had distorted touch perception and perceived a straight line as a curve. The pulp-writing test, using moving touch, is one method of examining mechanoreceptors and shows to what extent the patient perceives what touches the finger pulp; it gives a better indication of higher functions than the 2PD test.