Microsurgical skill assessment: toward skill-based surgical robotic control

A surgical skill assessment system was developed to quantify microsurgical skills. Infrared optical makers, an inertial measurement unit, and strain gauges were mounted on tweezers to record surgical tasks. In preliminary experiments, the tool tip trajectory, acceleration, and applied force were measured and microsurgery videos were evaluated by three expert surgeons. The preliminary results indicated the feasibility of the system by showing the significant difference between unskilled and skilled surgeons.

IgG4-related inflammatory pseudotumor of the trigeminal nerve: another component of IgG4-related sclerosing disease?

IgG4-related IPTs have been reported in various sites and may form part of the spectrum of systemic IgG4-related sclerosing disease. Some pseudotumors are clinically and radiologically indistinguishable from malignant tumors. We present the first case of an IgG4-related IPT of the trigeminal nerve diagnosed histopathologically without involvement of any of the common sites. The trigeminal nerve pseudotumor may represent a component of IgG4-related sclerosing disease.

Protected endovascular revascularization of subacute and chronic total occlusion of the internal carotid artery

BACKGROUND AND PURPOSE

The natural course of symptomatic carotid artery occlusion with hemodynamic impairment is poor. Surgical revascularization may improve the outcome; however, its efficacy has not been established yet. The goal of this study was to characterize the technical and clinical outcomes following endovascular recanalization of the ICA under cerebral circulatory protection.

MATERIALS AND METHODS

Endovascular recanalization was attempted in 8 patients with symptomatic ICA occlusions. The duration of the occlusion ranged from 7 days to 7 months (mean, 2.5 months), and the mean length of the occlusion was 95 mm. Cerebral hemodynamics ipsilateral to the side of the occlusion were severely impaired in all patients. The endovascular procedure was performed under total cerebral circulatory protection, beginning with proximal protection with a subsequent switch to distal protection after successful guidewire passage.

RESULTS

The occlusion was recanalized successfully in 7 of 8 patients (88%), resulting in improvement of ipsilateral cerebral hemodynamics without symptomatic stroke. Small asymptomatic ischemic lesions were detected in 6 of 8 patients (75%) on DWI, and 1 patient developed a mild groin hematoma. Ischemic episodes did not recur during the mean follow-up period of 19 months. However, 1 patient experienced asymptomatic reocclusion, which was re-treated successfully without complications, while another patient developed mild retinal hemorrhage at 3 months after the procedure due to the combination of antiplatelet and anticoagulant therapy.

CONCLUSIONS

Endovascular revascularization of an ICA occlusion is feasible and well-tolerated in patients with subacute or chronic total occlusion of the ICA.

Peroxisome proliferator-activated receptor gamma polymorphism is related to peak bone mass: the JPOS study

We analyzed 1,217 women to examine the effect of peroxisome proliferator-activated receptors gamma (PPARgamma) C161 --> T on bone status. Among 664 premenopausal women, the C161 --> T is associated with low bone mineral density (BMD) at the total hip and femoral neck. Moreover, the odds ratio for osteopenia or osteoporosis at the femoral neck was 1.98 for premenopausal CT/TT genotypes.

INTRODUCTION

The impact of PPARgamma on BMD has not been conclusively established. We examined if PPARgamma C161T polymorphism is associated with BMD and its change.

METHODS

We conducted a baseline survey in 1996 and a 10-year follow-up survey, Japanese Population-based Osteoporosis Study, with a sample population representative of Japanese women. Of these, 1,217 participants in the 1996 survey were analyzed cross-sectionally, while longitudinal analysis was performed on 563 women. A P value < 0.0042 (=0.05/12 for three menstrual statuses and four skeletal sites) was considered statistically significant after Bonferroni correction in multiple testing for cross-sectional analysis.

RESULTS

The total hip and femoral neck BMDs were significantly higher for CC genotype than for CT/TT genotypes among 664 premenopausal women (P = 0.0020, P = 0.0022, respectively). Compared to the CC genotype, the odds ratio for osteopenia or osteoporosis (T-scores below -1) at the femoral neck was 1.98 for premenopausal CT/TT genotypes with statistical significance (P = 0.0041). Change of BMD at either skeletal site during the follow-up period was not significantly different for either menstrual status.

CONCLUSIONS

We conclude that the PPARgamma C161T is associated with low peak bone mass.

Difference in the heat sensitivity of DNA‐dependent protein kinase activity among mouse, hamster and human cells

PURPOSE

To examine the heat sensitivity of DNA-dependent protein kinase (DNA-PK) activity in a variety of cultured mouse, hamster and human cell lines.

MATERIALS AND METHODS

Eight cell lines, which have been routinely used in our laboratory, were examined. Cells were heated at 44.0 +/- 0.05 degrees C and DNA-PK activity was measured by a DNA-pull-down assay followed by gel-electrophoresis. Cellular sensitivity to hyperthermia and/or X-ray was evaluated by a colony formation assay.

RESULTS

In mouse FSA1233 and FM3A cells, DNA-PK activity dropped to 15-16% of unheated control after 20 min of heating. In Chinese hamster V79 and CHO-K1 cells, kinase activity did not change appreciably after 20 min treatment but decreased to 60-70 and 22-23% after 40 or 60 min treatment, respectively. However, even after 180 min treatment, DNA-PK activity remained almost intact in human MOLT-4, MKN45 and A7 cells, and decreased only slightly in U937 cells. Hyperthermic radiosensitization was seen even in human cells but, as a trend, it was small compared with rodent cells.

CONCLUSIONS

The heat sensitivity of DNA-PK was clearly different among mouse, hamster and human cells. The results suggested a possibility that the role of DNA-PK inactivation in hyperthermic radiosensitization might be variable, depending on cells, and would reinforce the warning that the direct extrapolation of data from rodent cells might lead to overestimation of the effectiveness of hyperthermia on human cancer.

Decreased c‐Myc expression and its involvement in X‐ray‐induced apoptotic cell death of human T‐cell leukaemia cell line MOLT‐4

PURPOSE

To investigate the possible involvement of c-Myc and ceramide-c-Jun N-terminal kinase (JNK) pathway in X-ray-induced apoptotic cell death of MOLT-4 cells.

MATERIALS AND METHODS

The expressions of c-Myc protein and c-myc mRNA after X-irradiation were analysed by Western blotting and RT-PCR between radiosensitive MOLT-4 and radioresistant variant Rh-1a cells with less JNK activation than the parental cells. Apoptotic cell death was determined by a dye exclusion test, the appearance of chromatin condensation and DNA fragmentation. The effect of a JNK activator anisomycin or c-Myc inhibitor peptides (Int-H1-S6A, F8A) on the amount of c-Myc protein and on the induction of apoptosis was investigated, respectively.

RESULTS

In X-irradiated MOLT-4 cells, amounts of both c-myc mRNA and c-Myc protein rapidly decreased, which was followed by apoptotic cell death, while little change or limited reduction of c-Myc protein was observed in X-irradiated Rh-1a cells with accompanying higher cell viability. Exposure of MOLT-4 and Rh-1a cells to c-Myc inhibitor peptides similarly induced apoptotic cell death with decreases of c-Myc protein. Anisomycin rapidly induced JNK activation and a subsequent decrease of c-Myc protein, causing cell death in MOLT-4 cells. On the other hand, Rh-1a cells were more resistant to anisomycin than parental MOLT-4 cells, showing less JNK activation and a delayed decrease of c-Myc protein.

CONCLUSION

A decrease of c-Myc protein was considered important in X-ray-induced apoptotic cell death of MOLT-4 cells; activation of the JNK pathway caused reduction in the amounts of c-myc mRNA and c-Myc protein, and finally induced apoptotic cell death.

Negative regulation of MEKK1/2 signaling by serine-threonine kinase 38 (STK38)

Mitogen-activated protein kinases (MAPKs) are activated through the kinase cascades of MAPK, MAPK kinase (MAPKK) and MAPKK kinase (MAPKKK). MAPKKKs phosphorylate and activate their downstream MAPKKs, which in turn phosphorylate and activate their downstream MAPKs. MAPKKK proteins relay upstream signals through the MAPK cascades to induce cellular responses. However, the molecular mechanisms by which given MAPKKKs are regulated remain largely unknown. Here, we found that serine-threonine protein kinase 38, STK38, physically interacts with the MAPKKKs MEKK1 and MEKK2 (MEKK1/2). The carboxy terminus, including the catalytic domain, but not the amino terminus of MEKK1/2 was necessary for the interaction with STK38. STK38 inhibited MEKK1/2 activation without preventing MEKK1/2 binding to its substrate, SEK1. Importantly, STK38 suppressed the autophosphorylation of MEKK2 without interfering with MEKK2 dimer formation, and converted MEKK2 from its phosphorylated to its nonphosphorylated form. The negative regulation of MEKK1/2 was not due to its phosphorylation by STK38. On the other hand, stk38 short hairpin RNA enhanced sorbitol-induced activation of MEKK2 and phosphorylation of the downstream MAPKKs, MKK3/6. Taken together, our results indicate that STK38 negatively regulates the activation of MEKK1/2 by direct interaction with the catalytic domain of MEKK1/2, suggesting a novel mechanism of MEKK1/2 regulation.

Differential expression of two fructokinases in Oryza sativa seedlings grown under aerobic and anaerobic conditions

Fructokinases (EC 2.7.1.4) may play an important role in carbohydrate metabolism of Oryza sativa L. (rice) seedlings under anoxia. We present here the molecular and biochemical characterizations of two rice fructokinases, namely OsFK1 and OsFK2. The results show that, at both a transcriptional and a transductional level, OsFK1 is preferentially expressed under aerobic conditions, whereas OsFK2 is induced under anoxia. Substrate inhibition was demonstrated for OsFK1, while OsFK2 appears to be largely unaffected by fructose concentrations up to 10 mM. Sugar modulation of anoxia-induced proteins has been proposed, but our results on rice calli treated with or without glucose (10, 30 or 90 mM) for different time indicate that neither OsFK1 nor OsFK2 are sugar-regulated. We propose that OsFK2 plays a major role in fructose phosphorylation under anoxic conditions.

Numerical simulation of the intra-aneurysmal flow dynamics

SUMMARY

Intra-aneurysmal flow dynamics is analyzed qualitatively and quantitatively with numerical simulation technique, and presented for the future clinical application in embolizing cerebral aneurysms. From the volumetric data obtained by three-dimensional computed tomographic angiography, patient-specific vessel models were created for 16 middle cerebral artery aneurysms. Intraaneurysmal flow dynamics was visualized and analyzed qualitatively, and the geometrical parameters of vessels and aneurysms that affect the intra- aneurysmal flow dynamics were determined quantitatively by correlation analysis. The flow velocity was delayed in the aneurysm cavity, especially at its tip where the rupture usually occurs. The intra-aneurysmal flow dynamics was considerably influenced by the geometrical parameters that are related to the width of the neck and the branching angle of larger branch artery. The intra-aneurysmal flow dynamics is complex, and the numerical flow simulations with patient-specific vascular models seems effective in understanding the flow dynamics and planning the endovascular treatment of cerebral aneurysms.

Involvement of tenascin-C and PG-M/versican in flexor tenosynovial pathology of idiopathic carpal tunnel syndrome

Increased intra-carpal-tunnel pressure due to swelling of the flexor tenosynovium is the most probable pathological mechanism of idiopathic carpal tunnel syndrome (CTS). To clarify the role of tenascin-C and PG-M/versican, which have often been found to be involved in tissue remodeling and vascular stenosis in the pathogenesis of CTS, we histologically and biochemically examined the production of extracellular matrix in the flexor tenosynovium from 40 idiopathic CTS patients. Tenascin-C was temporarily expressed in the vessel wall, synovial lining and fibrous tissue, with expression regulated differently in each tissue. Tenascin-C expression by vessels correlated with disease duration and appeared to be involved in vascular lesion pathology. Morphometric analysis showed that tenascin-C expression by small arteries is correlated with PG-M/versican expression in surrounding connective tissue. PG-M/versican was also present at the neointima of severely narrowed vessels. Although tenascin-C expression by synovial lining and connective tissue shows marked regional variation and seems inconsistent, in vitro examination suggested that tenascin-C production by these tissues is regulated in response to mechanical strain on the flexor tenosynovium.

Nested polymerase chain reaction for assessing the clinical course of tuberculous meningitis

The authors examined the usefulness of nested PCR (N-PCR) to detect Mycobacterium tuberculosis (MTB) DNA in CSF for assessing the clinical course of tuberculous meningitis (TBM). N-PCR successfully detected MTB DNA in all nine CSF samples from patients with suspected TBM. During anti-tuberculosis treatments, N-PCR results converted from positive to negative, correlating with the improvement of the patient's clinical condition.

Biochemical markers of bone turnover predict bone loss in perimenopausal women but not in postmenopausal women-the Japanese Population-based Osteoporosis (JPOS) Cohort Study

INTRODUCTION

The predictive value of biochemical markers of bone turnover for subsequent change in bone density in a population sample of healthy women with a wide range of ages has not been fully established.

METHODS

We followed 1,283 women aged 15-79 years at baseline selected randomly from the inhabitants of three areas in Japan for 6 years, and examined 1,130 subjects with no disease or administration of drugs affecting bone metabolism. The annual change in bone density at the spine, total hip, and distal one third of the radius was determined during the follow-up period by dual x-ray absorptiometry and was compared among the groups using different levels of biochemical markers at baseline, including serum osteocalcin (OC) and bone-specific alkaline phosphatase (bone ALP), free and total (tDPD) forms of immunoreactive deoxypyridinoline, and type I collagen crosslinked C-terminal telopeptide (CTX) in urine.

RESULTS

Premenopausal women aged 45 years or older with elevated levels of OC, bone ALP, CTX, or tDPD showed significantly greater bone loss at most skeletal sites during the follow-up period than those with lower levels, after adjustment for the effects of age, height, weight, dietary calcium intake, regular exercise, and current smoking. The greatest coefficient of determination of the model was observed in the association between CTX and bone loss at the hip during the first 3 years of follow-up (42.8%). These subjects were pooled with perimenopausal women at baseline, and those who still menstruated at follow-up in this pooled group showed significant but more modest associations, whereas those who entered menopause during the follow-up period showed clear associations. However, early postmenopausal women with less than 5 or 10 years since menopause showed an association that was limited mostly to the distal radius, and other postmenopausal groups had virtually no association.

CONCLUSION

Biochemical markers of bone turnover may predict bone loss in women undergoing menopausal transition but may not predict bone loss in postmenopausal women.

Effects of the Cdx-2 polymorphism of the vitamin D receptor gene and lifestyle factors on bone mineral density in a representative sample of Japanese women: the Japanese Population-based Osteoporosis (JPOS) Study

Using a large-scale representative sample of the Japanese female population, we examined the effects of a single nucleotide polymorphism within a binding site of Cdx-2 in the promoter region of the vitamin D receptor gene on bone mineral density (BMD), and the interactions between this polymorphism and lifestyle factors on BMD. Fifty women were randomly selected from each of the 5-year age-stratified populations (15-79 years) in each of three chosen municipalities as a part of the Japanese Population-based Osteoporosis Study. BMD at the lumbar spine, hip, and distal forearm was measured using dual-energy X-ray absorptiometry at baseline and again in a follow-up study conducted 3 years later. Information on lifestyle factors was collected in a questionnaire and followed up in interviews. The G-to-A polymorphism within the Cdx-2 binding site was determined by a TaqMan allelic discrimination assay. At baseline, 1,340 women were analyzed. The baseline BMD in the ultradistal forearm in premenopausal women with the GG genotype was significantly lower than in those with other genotypes. There was no association between the Cdx-2 genotype and the change in BMD at any of the skeletal sites. We found significant associations between daily milk consumption and baseline BMD at some skeletal sites but only in subjects with the GG genotype. In conclusion, the Cdx-2 polymorphism alone did not have a substantial effect on BMD in Japanese women. However, this polymorphism might have some effect in women with low calcium intake.

Sodium orthovanadate suppresses DNA damage-induced caspase activation and apoptosis by inactivating p53

We previously reported that p42/SETbeta is a substrate for caspase-7 in irradiated MOLT-4 cells, and that treating the cells with sodium orthovanadate (vanadate) inhibits p42/SETbeta's caspase-mediated cleavage. Here, we initially found that the inhibitory effect of vanadate was due to the suppression of caspase activation but not of caspase activity. Further investigations revealed that vanadate suppressed upstream of apoptotic events, such as the loss of mitochondrial membrane potential, the conformational change of Bax, and p53 transactivation, although the accumulation, total phosphorylation, and phosphorylation of six individual sites of p53 were not affected. Importantly, vanadate suppressed p53-dependent apoptosis, but not p53-independent apoptosis. Finally, gel-shift and chromatin immunoprecipitation assays conclusively demonstrated that vanadate inhibits the DNA-binding activity of p53. Vanadate is conventionally used as an inhibitor of protein tyrosine phosphatases (PTPs); however, we recommend that the influence of vanadate not only on PTPs but also on p53 be considered before using it.

Subfrontal schwannoma

Subfrontal schwannoma is a rare disease, which can be mis-diagnosed as an olfactory meningioma or a neuroblastoma, because of similar clinical symptoms and signs and neuroradiological features. Especially for young subjects, olfactory neuroblastoma should be carefully differentiated, since the management strategies for those lesions are significantly different. The craniofacial approach is often needed for the resection of a neuroblastoma. We report a case of 14-year old boy in which olfactory neuroblastoma was suspected prior to surgery, but turned out to be a schwannoma histologically. Molecular genetic examination revealed neither NF2 gene mutation nor loss of heterozygosity of chromosome 22q, unlike common schwannomas.

Spinal intramedullary ependymal cyst: a case report and review of the literature

We report a rare case of spinal intramedullary ependymal cyst in a 44-year-old female and reviewed 12 cases reported in the literature. The patient presented with slowly progressive lower limb paresis. She underwent biopsy of the cyst wall and placement of a cysto-subarachnoid shunt with complete recovery at the follow-up examination 18 months after surgery. This is a benign lesion and appropriate management should be performed at an early stage of the disease.

Diffusion property following functional hemispherectomy in hemimegalencephaly

Diffusion-tensor imaging (DTI), a unique magnetic resonance technique for analysis of diffusion-anisotropy of the brain, can identify subtle white matter changes in vivo. To investigate changes of truncated neurofibers, DTI was conducted prior to and following functional hemispherectomy in a female infant for refractory epilepsy associated with hemimegalencephaly. Anisotropy of the amputated pyramidal tract decreased relative to the unaffected side after surgery, which reflects secondary degeneration in neurofibers. In DTI applied to infants, differentiation between developmental changes and changes associated with the current phenomenon must be evaluated cautiously. Standardization of diffusion-tensor analysis of developmental change is desirable.

Resolution of spinal epidural haematoma without surgery in a haemophilic infant

Non-traumatic spinal epidural haematoma is a rare complication of haemophilia. We report a seven-month-old boy who presented with symptomatic spinal epidural haematoma. He was found to have a hemophilia B trait, and after factor IX replacement, his neurological signs were stabilized and follow-up MRI demonstrated rapid resolution of the haematoma. This illustrative case suggests that surgical intervention can be deferred as the first step in treating spinal epidural haematoma in a haemophilic infant.

Differentiation and apoptosis without DNA fragmentation in cultured Schwann cells derived from wallerian-degenerated nerve

The Schwann cell cables provide particularly favorable sites for the growth of regenerating axonal sprouts. However, if they remain denervated, endoneurial fibrosis takes place with the Schwann cells atrophying and total Schwann cell number gradually decrease with time. Even when regenerating axonal sprouts invade into the cables, Schwann cells do not survive for long periods if they fail to make axonal contact. These observations strongly suggest the involvement of apoptosis in peripheral nerve degeneration and regeneration. So, we investigated the behavior of Schwann cells prepared from wallerian-degenerated adult rat sciatic nerve in vitro. The secondary cultured Schwann cells showed serial changes in morphology, mitotic activity and migratory activity as they do during Schwann cell cable formation in vivo. At the final stage of differentiation, the Schwann cells became rounded and detached from the flask with extensive blebbing. Electron micrographs clearly demonstrated typical cytoplasmic changes of apoptosis, but, nuclei of most of the cells retained their size and morphology with residual nucleolar structures. An agarose gel electrophoresis of DNA clearly demonstrated that there was not any DNA fragmentation up to 120 h after detachment. Results by in situ apoptosis detection assay did not show any DNA degradation despite the substantial decrease in Schwann cell number. In conclusion, during peripheral nerve degeneration and regeneration, supernumerary Schwann cells are removed by apoptosis, however, it lacks most of the nuclear events of usual apoptosis.