Changes in the fluctuation of interbeat intervals in spontaneously beating cultured cardiac myocytes: experimental and modeling studies

Isolated and cultured neonatal cardiac myocytes contract spontaneously and cyclically, and have the properties of a non-linear oscillator. In this study, we have analyzed the relationship between the fluctuation of contraction rhythm of spontaneously beating cultured cardiac myocytes, and the coupling strength among them. The coefficient of variation of contraction intervals increased transiently in the early stages of incubation, and then decreased almost monotonically with time. The contraction rhythm of the myocytes became synchronized in the late stage of the culture. The day on which synchronization occurred almost coincided with the day when the coefficient of variation reached its lowest value. In addition, we have performed a mathematical analysis using interacting Bonhoeffer-van der Pol oscillators to clarify the mechanisms underlying the changes in the fluctuation of contraction rhythm with time. As the coupling strength among oscillators increased, the coefficient of variation of oscillation periods increased temporarily, but then decreased rapidly when the oscillators showed synchronization. These results suggest that the changes in the fluctuation of beating rhythm result from the increase in strength of electrical coupling among spontaneously beating cardiac myocytes.

Synergistic effects of MAP2 and MAP1B knockout in neuronal migration, dendritic outgrowth, and microtubule organization

MAP1B and MAP2 are major members of neuronal microtubule-associated proteins (MAPs). To gain insights into the function of MAP2 in vivo, we generated MAP2-deficient (map2(-/-)) mice. They developed without any apparent abnormalities, which indicates that MAP2 is dispensable in mouse survival. Because previous reports suggest a functional redundancy among MAPs, we next generated mice lacking both MAP2 and MAP1B to test their possible synergistic functions in vivo. Map2(-/-)map1b(-/-) mice died in their perinatal period. They showed not only fiber tract malformations but also disrupted cortical patterning caused by retarded neuronal migration. In spite of this, their cortical layer maintained an "inside-out" pattern. Detailed observation of primary cultures of hippocampal neurons from map2(-/-)map1b(-/-) mice revealed inhibited microtubule bundling and neurite elongation. In these neurons, synergistic effects caused by the loss of MAP2 and MAP1B were more apparent in dendrites than in axons. The spacing of microtubules was reduced significantly in map2(-/-)map1b(-/-) mice in vitro and in vivo. These results suggest that MAP2 and MAP1B have overlapping functions in neuronal migration and neurite outgrowth by organizing microtubules in developing neurons both for axonal and dendritic morphogenesis but more dominantly for dendritic morphogenesis.

[Cost and effectiveness of exercise therapy for patients with essential hypertension]

PURPOSE

While exercise therapy is established as an appropriate treatment for essential hypertension, its economic profile has not been fully evaluated. The purpose of this study is to evaluate cost and effectiveness in comparison with drug therapy.

SUBJECTS AND METHODS

The study subjects were hypertensive patients under treatment at an outpatient clinic. Fifty-seven were selected on a non-randomized manner for exercise therapy and the same number of patients was chosen for drug therapy after matching age, sex, medication and complications. The following data were collected during three months of intervention. 1) Effectiveness: Change of systolic blood pressure before and after the intervention. 2) Cost: equipment, personnel expenses for exercise therapy and fees for health check-ups (exercise therapy); fees for consultation, laboratory examination and medications (drug therapy), 3) Cost-effectiveness: cost per 1 mmHg systolic blood pressure reduction. We evaluated the variance of cost-effectiveness by controlling the number of program participants, personnel expenses, and equipment expenses of exercise therapy. We also simulated how the cost-effectiveness of exercise therapy would improve by modifying the number of exercise participants, personnel and equipment expenses.

RESULTS

The cost-effectiveness per 1 mmHg systolic blood pressure reduction was yen 11,268 for exercise therapy and yen 2,441 for drug therapy. Extending program facilities and increasing the number of participants would improve the cost-effectiveness of exercise therapy, but there were limitations to how far this could be achieved in the hospital setting.

CONCLUSION

Differences in cost-effectiveness between exercise and drug therapies are attributed to differences in personnel expenses. Although they could be reduced by managerial effort of the hospital to some extent, outsourcing of exercise therapy to community-based facilities should be considered.

[The Combination therapy of calcitonin and other medicines in the treatment of osteoporosis]

Because of the unique analgesic effect of calcitonin, it is very useful in the treatment of osteoporosis cases who complain mainly back pain. Besides, it has anti-osteoresorptive effect and when it is used in combination with other medicines, like calcium, vitamin D(3) , estrogen and vitamin K(2), the effect of improving bone contents or fracture prevention has been reported to be increased. In this article, the efficacy of the combination therapy of calcitonin and other medicines is described based on the recent reports.

The role of extended radical operation for pancreatic cancer

BACKGROUND/AIMS

To clarify the indication of extended operation for pancreatic carcinoma, a clinical study was carried out.

METHODOLOGY

From July 1981 to 1999, 196 of 307 (63.8%) patients with pancreatic carcinoma underwent resection of the tumor. Portal vein resection was performed in 145 of these 196 (74.0%) resected cases. The postoperative survival rate was studied according to the operative and histopathological findings.

RESULTS

In spite of the aggressive surgery, there was no patient who survived over 3 years after operation in the group carcinoma-positive on the surgical margins. Patients who survived over 3 years postoperatively were observed in the group of carcinoma-free surgical margins.

CONCLUSIONS

The most important indication of extended operation combined with portal vein resection for pancreatic cancer is to obtain surgical cancer-free margins. There is no indication of extended operation for cases in which surgical margins will become cancer-positive, if such an operation is employed.

Gene therapy for pancreatic cancer

Despite improvements in surgical care and locoregional therapy, the prognosis of patients with pancreatic cancer has seen little improvement over the last several decades. It is difficult to diagnose pancreatic cancer at its earliest stages when it is amenable to cure by surgical resection because it is too small to produce symptoms in the affected patient. Recent improvements in radiographic modalities aimed at earlier detection and extent of cancer spread have enabled the clinician to provide the most efficacious treatment regimen possible. Nevertheless, pancreatic cancer is very aggressive locally and frequently metastasizes to the liver and peritoneum. New strategies are necessary to treat pancreatic cancer and gene therapy offers hope in this regard. Many studies have revealed the promise of gene therapy in the treatment of pancreatic cancer in rodent models. Early clinical trials are ongoing to evaluate the success of these gene therapy regimens in humans. In this article we review the gene therapy strategies currently employed in the fight against pancreatic cancer, including antisense strategies, gene-directed prodrug activation therapy, promoter gene strategies, and oncolytic viral therapy.

Surgical treatment of intraductal papillary-mucinous tumors of the pancreas

BACKGROUND/AIMS

IPMT (Intraductal papillary-mucinous tumor of the pancreas) is increasingly recognized. The aim of this study was to investigate the appropriate surgical treatment for these tumors.

METHODOLOGY

Between January 1981 and September 1998, 62 patients with IPMT underwent surgery. We retrospectively examined the clinicopathological features and surgical outcomes of the patients.

RESULTS

The types of IPMT were as follows: hyperplasia (20); adenoma (31); and carcinoma, both invasive (5) and noninvasive (6). Lymph node metastasis was found in 36% of the carcinomas. The size of mural nodules was more than 3 mm in all adenoma or carcinoma cases, while the percentage of hyperplasia less than 3 mm was 75%. Intraoperative pancreatoscopy and annular array ultrasonography were very useful, because they detected 10 lesions that could not be found by preoperative examinations, such as computed tomography, endoscopic retrograde pancreatography, and endoscopic ultrasonography. All patients underwent surgical resection, including 10 pancreaticoduodenectomies (Whipple's procedure), 10 pylorus-preserving pancreaticoduodenectomies, 13 pancreatic head resections with segmental duodenectomies, 17 distal pancreatectomies, 9 segmental resections of the pancreas, 2 duodenum-preserving pancreatic head resections, and 1 total pancreatectomy. No operative or hospital death was observed. The postoperative survival rate at 5 years was 71.6% for carcinoma in IPMT. All of the cases with hyperplasia, adenoma and noninvasive carcinoma survived. Only two of the patients with invasive carcinoma died.

CONCLUSIONS

IPMT had a favorable prognosis, as compared with pancreatic duct carcinoma. When selecting a surgical procedure for treating these tumors, it is important to confirm the tumor extent, as well as the diagnosis of invasion or noninvasion. In cases with invasion, radical resection is required. On the other hand, organ-function-preserving procedures should be selected for diseases without invasion.

[Study of lymphocyte and NK cell activity during mild hypothermia therapy]

Infectious disease is a common complication of mild hypothermia therapy. However, very little has been reported about immune response during hypothermia. In the present study, the number and subset of peripheral lymphocytes and mitogen response to phytohaemagglutinin (PHA) and concanavalin A (Con-A) were examined in 14 patients who received mild hypothermia therapy. NK cell ratio and activity were also examined in the same patients. Six out of 14 patients had complicated infectious diseases during mild hypothermia therapy. Five of them had pneumonia and the remaining one had thrombophlebitis. The number of peripheral lymphocytes decreased in patients whose rectal temperature was less than 34.5 degrees C, whereas mitogen response of lymphocytes to PHA and Con-A remained unchanged in patients whose rectal temperature was above 34.0 degrees C. NK cell ratio and cytotoxicity decreased in patients whose rectal temperature was less than 34.5 degrees C, including infectious cases. These results suggested that, under hypothermia therapy, immune responses of the patients whose rectal temperature was less than 34.5 degrees C were disturbed because of the reduced number of peripheral lymphocytes and depression of NK cell activity.

Intraoperative diagnosis of pancreatic cancer extension using IVUS

BACKGROUND/AIMS

Pancreatic cancer easily invades retroperitoneal tissue, especially the portal vein and extrapancreatic nerve plexus. We evaluated the diagnostic accuracy of intraportal endovascular ultrasonography in portal vein and extrapancreatic nerve plexus invasion.

METHODOLOGY

Intraportal endovascular ultrasonography was performed in 78 cases of pancreatic cancer (head 67, body 8, total 3). Intraportal endovascular ultrasonography was performed intraoperatively from the superior mesenteric vein with an 8-French, 20-MHz intravascular ultrasound catheter. Three-dimensional intraportal endovascular ultrasonography was constructed by volume rendering.

RESULTS

Intraportal endovascular ultrasonography visualized the portal vein as an echogenic band with a thickness of 0.5 mm to 1.0 mm. The diagnostic criterion of portal vein invasion was obliteration of this echogenic band. Intraportal endovascular ultrasonography visualized segment II of the extrapancreatic nerve plexus as the high-echoic area around the inferior pancreaticoduodenal artery. The diagnostic criterion of extrapancreatic nerve plexus invasion was low-echoic infiltration around the inferior pancreaticoduodenal artery. The sensitivity, specificity, and overall accuracy of intraportal endovascular ultrasonography for diagnosis of portal vein invasion was, respectively, 97.4%, 92.5%, and 94.9%. The values for diagnosis of extrapancreatic nerve plexus invasion, respectively, were 94.4%, 97.1%, and 96.2%. Three-dimensional intraportal endovascular ultrasonography depicted the invasion area as a defect of the portal vein wall.

CONCLUSIONS

Intraportal endovascular ultrasonography detected subtle portal invasion and provided accurate portal invasion area which was useful for portal vein an reconstruction. Intraportal endovascular ultrasonography could also diagnose the extrapancreatic nerve plexus invasion of segment II.

The role of adjuvant therapy for pancreatic cancer

BACKGROUND/AIMS

In spite of radical pancreatectomy with lymphadenectomy for adenocarcinoma of the pancreas, survival remains poor. We add two forms of adjuvant therapy, i.e., intraoperative radiotherapy and liver perfusion chemotherapy, to the radical resection. The aim of this study is to investigate the utility of these two forms of adjuvant therapy prospectively and to review their effectiveness.

METHODOLOGY

One hundred and ninety-six patients with pancreatic cancer who underwent radical pancreatectomy in our institute were enrolled. We conducted intraoperative radiation therapy 30 Gy against the retroperitoneal connective tissues around the superior mesenteric artery during surgery. Adjuvant liver perfusion chemotherapy was added immediately after operation via the portal vein using 5-fluorouracil (250 mg/body/day) for 3 to 4 weeks continuously. Overall survival analyses were done by the method of Kaplan and Meier.

RESULTS

Intraoperative radiation therapy did not influence the prognoses directly. However, the patients who received adjuvant liver perfusion chemotherapy had better prognoses (P < 0.05).

CONCLUSIONS

Although adjuvant therapy after radical resection with wide lymphadenectomy improves prognoses, the results are still not satisfactory. We should develop a new and more efficacious treatment.

Association between a polymorphism of the transforming growth factor-beta1 gene and genetic susceptibility to ossification of the posterior longitudinal ligament in Japanese patients

STUDY DESIGN

A study was conducted to determine the association between polymorphism of the transforming growth factor-beta1 (TGF-beta1) gene and ossification of the posterior longitudinal ligament (OPLL) prevalence.

OBJECTIVE

To examine whether the T869-->C polymorphism of the TGF-beta1 gene is associated with genetic susceptibility to OPLL in Japanese subjects.

SUMMARY OF BACKGROUND DATA

In the posterior longitudinal ligament, OPLL is associated with abnormal calcium metabolism. Several candidate genes are associated with the prevalence of OPLL. In the ossified matrix and chondrocytes of adjacent cartilaginous areas of OPLL, TGF-beta1 is overexpressed.

METHODS

The TGF-beta1 genotype was identified with an allele-specific polymerase chain reaction method in 319 Japanese subjects (46 subjects with OPLL and 273 control subjects).

RESULTS

There was a significant association between the T869-->C genotype and the prevalence of OPLL in the cervical spine. Multivariable logistic regression analysis, adjusted for gender, age, height, and body weight, showed that the frequency of the C allele was significantly higher in subjects with OPLL than in control subjects.

CONCLUSIONS

The T869-->C polymorphism of the TGF-beta1 gene is a genetic determinant of a predisposition to OPLL, with the C allele representing a risk factor for genetic susceptibility to OPLL in Japanese subjects. Therefore, TGF-beta1 genotyping may be useful in the prevention of OPLL.

Cyclodextrin-based molecular machines

Cyclodextrins have been used as a cyclic component in the construction of supramolecular architectures. Recently they have been studied as a component in the construction of rotaxanes and catenanes. A cyclodextrin ring can translocate in some rotaxane and catenane structures. Therefore, much attention has been given to cyclodextrins as a component of molecular shuttles, motors, and machines. Attempts to design and synthesize molecular-level machines using cyclodextrins as a cyclic component are described.

Pronounced activity of enzymes through the incorporation into the core of polyion complex micelles made from charged block copolymers

Compartmentalization of enzymes in the nanometric-scaled container, to improve their stability and availability, has recently attracted a strong interest in the field of pharmaceutics. In this study, the enzymatic activity of lysozyme in the core of polyion complex (PIC) micelles, which were formed from egg white lysozyme and poly(ethylene glycol)-poly(alpha,beta-aspartic acid) block copolymer (PEG-P(Asp)), was evaluated using a colorimetric method. Apparent enzymatic activity of lysozyme entrapped in the core of PIC micelles remarkably increased compared to that of free lysozyme, which is mainly attributed to a decrease in the observed Michaelis constant (K(m,obs)). The reciprocal of the K(m,obs) values nicely correlated to the corona thickness of PIC micelles, suggesting that the corona layer of PIC micelle may act as the reservoir of the substrate, p-nitrophenyl penta-N-acetyl-beta-chitopentaoside. This result indicates that the enzymatic activity can be controlled by changing the corona thickness of PIC micelles through a variation in the mixing ratio of PEG-P(Asp) to lysozyme. This type of PIC micelle system entrapping enzyme in the core might be useful for the design of diagnostic as well as targetable therapeutic systems of enzyme including antibody-directed enzyme prodrug therapy (ADEPT).

A gene encoding a hydrophobin, fvh1, is specifically expressed after the induction of fruiting in the edible mushroom Flammulina velutipes

A cDNA clone of the gene fvh1 was previously isolated from a preprimordial cDNA library made from the basidiomycete Flammulina velutipes. Sequence analysis showed that fvh1 encoded for a hydrophobin, a small fungal protein usually secreted by filamentous fungi. FVH1 had a highly conserved arrangement of eight cysteine residues, a putative N-terminal signal sequence and a hydropathy pattern characteristics of class I hydrophobin. A genomic fvh1 clone was isolated from a F. velutipes genomic DNA library and sequenced. Several putative promoter elements and three small introns of fvh1 were identified in this clone. Southern blot analysis of genomic DNA showed that fvh1 was a single copy gene. Northern analysis indicated that fvh1 was specifically and abundantly expressed in mycelia after the induction of fruiting and during fruit body initiation. It was not expressed in mycelia before the induction of fruiting or in mature fruit bodies.

Physicochemical properties and nuclease resistance of antisense-oligodeoxynucleotides entrapped in the core of polyion complex micelles composed of poly(ethylene glycol)-poly(L-lysine) block copolymers

In this study, the physicochemical properties of polyion complex (PIC) micelles formed from antisense-oligodeoxynucleotides (antisense-ODN) and poly(ethylene glycol)-poly(L-lysine) block copolymers (PEG-PLL) were investigated to utilize them as a novel formulation for antisense-ODN delivery. Angular and concentration dependences of the diffusion coefficient of PIC micelles were evaluated by dynamic light scattering. Results suggested that the formed PIC micelles may have spherical shape with core-shell structure, in which the PIC core formed from antisense-ODN and PLL segment was surrounded by a PEG shell. The average radius of PIC micelles was dependent on the chain length of the PLL segment and was not influenced by the change in the length of ODN molecules at least in the range between 15 and 20 base pairs. Critical association concentration (cac) of PIC micelles was then determined from a profile of light scattering intensity versus concentration (Debye plots). Cac is ca. 0.20 mg/ml, which is low enough to ensure the micelle stability in very diluted condition as is the case with systemic injection into the blood compartment for antisense-ODN therapy. Furthermore, the stability of antisense-ODN against deoxyribonuclease I (DNase I) attack was evaluated using capillary gel electrophoresis, revealing that the complexation of antisense-ODN with PEG-PLL effectively prohibited DNase I attack. These characteristics of the PIC micelle system highlight its promising feature as ODN carrier used in the field of targeting therapy.

Hemostatic activation in spontaneous intracerebral hemorrhage

BACKGROUND AND PURPOSE

There is no in-depth information available on the changes in hemostatic systems in patients in the acute phase of spontaneous intracerebral hemorrhage (ICH). This study was conducted to assess the relationships between the changes in hemostatic systems and clinical parameters in patients in acute-phase ICH.

METHODS

The records of 358 patients admitted within 6 hours of onset of ICH were reviewed to examine the relationships between changes in hemostatic systems and computed tomographic findings and clinical parameters.

RESULTS

-The white blood cell counts and the levels of thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer in patients with intraventricular extension (IVE) or subarachnoid hemorrhage (SAH) were significantly (P<0.05) higher than those in patients without IVE or SAH. Most of the hemostatic system parameters in patients without IVE or SAH showed no significant differences compared with normal subjects. Multiple linear regression analysis revealed that the levels of thrombin-antithrombin complex significantly increased with an increase in the amount of SAH (P<0.001) and IVE (P<0.001). The levels of thrombin-antithrombin complex were not significantly associated with the volume of intraparenchymal hematoma. The level of the complex, however, was significantly (P<0.001) and independently associated with the presence of IVE or SAH (multiple logistic regression analysis).

CONCLUSIONS

The systemic activation of hemostatic systems in ICH patients seems to take place only when blood reaches the subarachnoid space. The intraparenchymal hematoma itself seems unlikely to activate hemostatic systems in peripheral blood, although the hematoma is expected to cause local activation of hemostatic systems.

Block copolymer micelles for drug delivery: design, characterization and biological significance

Recently, colloidal carrier systems have been receiving much attention in the field of drug targeting because of their high loading capacity for drugs as well as their unique disposition characteristics in the body. This paper highlights the utility of polymeric micelles formed through the multimolecular assembly of block copolymers as novel core-shell typed colloidal carriers for drug and gene targeting. The process of micellization in aqueous milieu is described in detail based on differences in the driving force of core segregation, including hydrophobic interaction, electrostatic interaction, metal complexation, and hydrogen bonding of constituent block copolymers. The segregated core embedded in the hydrophilic palisade is shown to function as a reservoir for genes, enzymes, and a variety of drugs with diverse characteristics. Functionalization of the outer surface of the polymeric micelle to modify its physicochemical and biological properties is reviewed from the standpoint of designing micellar carrier systems for receptor-mediated drug delivery. Further, the distribution of polymeric micelles is described to demonstrate their long-circulating characteristics and significant tumor accumulation, emphasizing their promising utility in tumor-targeting therapy. As an important perspective on carrier systems based on polymeric micelles, their feasibility as non-viral gene vectors is also summarized in this review article.

Glomerular crescents in renal amyloidosis: an epiphenomenon or distinct pathology?

There have been several reports of cases of renal amyloidosis with glomerular crescents. However, it is not clear whether the association is fortuitous or pathogenic related. The present study analyzed 105 cases of renal amyloidosis (61 autopsy cases and 44 biopsy cases) and found glomerular crescents in 14 (13.3%) cases. Among the 14 cases with crescents, a female predominance was noted (male: female, 3: 11) and rheumatoid arthritis was the most common primary disease of amyloidosis. Immunohistochemical analysis demonstrated amyloid protein of AA type in 12 cases. According to the histologic classification, there were 11 cases of mesangial nodular type, which was almost exclusively accompanied by AA amyloid deposition. Of note, the incidence of crescents neither correlated with the extent of amyloid deposition nor the presence of nephrotic syndrome. By contrast, localization of amyloid deposition was closely related to crescent formation. Moreover, electron microscopic observation displayed rupture of the glomerular basement membrane at the site of amyloid deposition. Our results indicated that glomerular crescents were more frequently associated with renal amyloidosis than previously appreciated. Rupture of the fragile glomerular basement membrane by amyloid deposition, as revealed by immunostaining and electron microscopy, may be the mechanism of crescent formation. We suggest that glomerular crescents are a distinct pathology associated with renal amyloidosis, not fortuitous conditions.

Idiopathic portal hypertension associated with systemic lupus erythematosus

A case of idiopathic portal hypertension (IPH) associated with systemic lupus erythematosus (SLE) is reported in a 38-year-old man who had been diagnosed with SLE and treated for 18 years. Esophageal varices. found in 1994 on endoscopic examination, had been followed up for 2 years. On July 16, 1996, he was admitted to Nagoya University Hospital because there was a high risk of bleeding from the esophageal varices due to severe thrombocytopenia. As partial splenic embolization had temporarily controlled the thrombocytopenia, splenectomy and devascularization of the stomach vessels were performed after endoscopic ligation of the esophageal varices. Histological specimens of wedge biopsied liver showed chronic inactive hepatitis without cirrhosis. The presence of anticardiolipin antibody, indicated by positivity for lupus anticoagulant, was suggestive of the presence of a common immunological mechanism in the etiology of SLE and IPH.

High-field magnetic resonance imaging in patients with moyamoya disease

OBJECT

The purpose of this study was to assess the utility of high-field magnetic resonance (MR) imaging as a quantitative tool for estimating cerebral circulation in patients with moyamoya disease.

METHODS

Eighteen patients with moyamoya disease who were scheduled to undergo revascularization surgery and 100 healthy volunteers were examined using T2-reversed MR imaging performed using a 3-tesla system. Ten of the 18 patients underwent a second study between 1 year and 3 years after revascularization. Magnetic resonance images obtained in the patients with moyamoya disease were statistically analyzed and compared with those obtained in healthy volunteers. The MR imaging findings were also correlated with results of single-photon emission computerized tomography and conventional cerebral angiography studies. Transverse lines in the white matter (medullary streaks) were observed in almost all persons. In healthy volunteers, the diameter sizes of the medullary streaks increased significantly with age (p < 0.001). Multiple logistic regression analysis revealed that age-adjusted medullary streak diameters were significantly larger in patients with moyamoya disease (p < 0.001). Diameter sizes also increased significantly with the increased severity of cerebral hypoperfusion (p < 0.001) and a higher angiographically determined stage of the disease (p < 0.001). Diameter sizes decreased significantly after surgery (p < 0.001).

CONCLUSIONS

The increases in medullary streak diameters observed in patients with moyamoya disease appear to represent vessels dilated due to cerebral hypoperfusion. High-field T2-reversed MR imaging is useful in estimating cerebral circulation in patients with moyamoya disease.

Hip fracture prevention trial using hip protectors in Japanese nursing homes

A method to protect the hips during falls could effectively reduce the incidence of hip fractures. We report the results of the first hip protector trial in Japan, performed between July 1996, and September 1999. One hundred and sixty-four elderly female residents of nursing homes, with Activities of Daily Living above the wheelchair level, agreed to participate in this study. Among them, 88 were randomly selected to wear a hip protector and 76 controls did not. All falls and resulting injuries were recorded daily. In anthropometric measurements and ultrasonic bone evaluation, no significant differences were found between the two groups, except in height. During an average of 377 days, the wearers and the non-wearers fell a total of 131 and 90 times, respectively. Among the wearers, there were two non-hip fractures and one hip fracture, so the annual hip fracture rate was calculated at 1.2%, against 8 hip fractures among the non-wearers, or 9.7% per year. The hip fracture rate was significantly lower among the wearers than non-wearers, while the annual number of falls per subject and the distribution of fallers remained the same. According to Cox's proportional hazard regression analysis, the effect of the hip protector on hip fracture prevention was independent of anthropometric data, ultrasonic bone assessment values or number of falls. Moreover, even after limiting the subjects to fallers only, the annual hip fracture rate in non-wearers was higher than in wearers (19.8% vs 2.0%) and the annual hip fracture rate per fall in wearers was lower than that in non-wearers (0.8% vs 8.2%). It was thus concluded that the hip protector is a beneficial device for the prevention of hip fractures.

Relationship between osteoprotegerin/osteoclastogenesis inhibitory factor concentration in synovial fluid and disease severity in individuals with osteoarthritis of the knee

We studied the relationship between osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) concentration in synovial fluid from individuals with osteoarthritis (OA) of the knee and the severity of this condition. The study population included 111 Japanese women with knee OA (153 knees) and 23 normal controls. Osteoarthritic changes were graded according to the system of Kellgren and Lawrence. The concentration of OPG/OCIF in synovial fluid increased with severity of knee OA and was significantly higher in individuals with OA of grade IV than in those with OA of grade 0 or grade 1. It has been shown in a previous study that administration of OPG/OCIF prevents cartilage destruction in adjuvant-induced arthritis in rats. The increase in the concentration OPG/OCIF in synovial fluid of individuals with knee OA might thus reflect a compensatory response to degeneration of articular cartilage and serve to protect cartilage rather than be a cause of OA.

Inhibitory mechanism by polysialic acid for lamina-specific branch formation of thalamocortical axons

During development, thalamocortical axons form arbors primarily in layer 4 of the neocortex. This lamina-specific branch formation was studied in cultures of rat thalamic explants grown next to chemically fixed cortical slices. After a week in vitro, thalamic axons formed branches specifically in the target layer of fixed cortical slices, regardless of the orientation of the ingrowth. This in vitro system permits a direct assessment of contributions of membrane-associated molecules to thalamic axon branch formation. To this end, the present study uses three enzymatic perturbations: chondroitinase, phosphatidylinositol phospholipase C, or the polysialic acid (PSA)-specific endoneuraminidase (endo N). With endo N pretreatment of cortex, the number of branch points was increased significantly, whereas branch tip length was decreased. In addition, the localization of branch points to the target layer was weakened considerably. These features of branch formation were not altered by the other two enzymatic treatments, except that branch tips were shortened by chondroitinase treatment to the same extent as in endo N treatment. These results suggest that membrane-bound components are involved in lamina-specific branch formation of thalamocortical axons, and in particular that PSA moieties contribute to laminar specificity by inhibiting branch emergence in inappropriate layers.