Zinc-substituted hydroxyapatite: a biomaterial with enhanced bioactivity and antibacterial properties

Hydroxyapatite (HA) is a synthetic biomaterial and has been found to promote new bone formation when implanted in a bone defect site. However, its use is often limited due to its slow osteointegration rate and low antibacterial activity, particularly where HA has to be used for long term biomedical applications. This work will describe the synthesis and detailed characterization of zinc-substituted HA (ZnHA) as an alternative biomaterial to HA. ZnHA containing 1.6 wt% Zn was synthesized via a co-precipitation reaction between calcium hydroxide, orthophosphoric acid and zinc nitrate hexahydrate. Single-phase ZnHA particles with a rod-like morphology measuring ~50 nm in length and ~15 nm in width, were obtained and characterized using transmission electron microscopy and X-ray diffraction. The substitution of Zn into HA resulted in a decrease in both the a- and c-axes of the unit cell parameters, thereby causing the HA crystal structure to alter. In vitro cell culture work showed that ZnHA possessed enhanced bioactivity since an increase in the growth of human adipose-derived mesenchymal stem cells along with the bone cell differentiation markers, were observed. In addition, antibacterial work demonstrated that ZnHA exhibited antimicrobial capability since there was a significant decrease in the number of viable Staphylococcus aureus bacteria after in contact with ZnHA.

Peierls mechanism of the metal-insulator transition in ferromagnetic hollandite K2Cr8O16

Synchrotron x-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K(2)Cr(8)O(16) is accompanied by a structural distortion from the tetragonal I4/m to monoclinic P112(1)/a phase with a √2×√2×1 supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems.

[Pericardiocentesis and drainage]

Diagnosis and treatment of pericardial effusion need to be performed frequently by pericardiocentesis or surgical pericardiotomy. Large retention of the effusion is treated conventionally by percutaneous blind puncture, while possible injuries to the myocardium are avoided feasibly by ultrasonically-guided puncture even in case that the effusion remains moderately or unevenly inside the pericardial space. Along with the puncture, drainage tube introduced into the pericardial sac using coaxial method contributes to relieving coexistent pericardial or chronic exudation. The pericardium is also surgically approached traditionally via parasternal, subxiphoid, or lateral-thoracic route. Specimen of the pericardium is optionally sampled to promote analyzing the pathogenesis, and drainage tubes of larger diameter facilitate evacuating the purulent substance in the settings of infectious origins. The lateral thoracotomy is occasionally applied to the effusion around the posterior aspect of the heart, which is preferably replaced by less-invasive video-assisted procedure. Those several measures would facilitate the treatment for pericardial effusion.

Websites offer helpful information concerning consultation with headache specialists

Patients with severe primary headache may benefit from consultation with headache specialists, but doctor attendance rates in Japan are very low. More headache patients might consult headache specialists if these specialists were more widely recognized by the public. To determine what information prompted patients to seek consultation with a headache specialist, we questioned 256 primary headache patients about the source of the helpful information concerning consultation with headache specialists. From 191 patients, a total of 235 responses to the questionnaire were obtained. The most common response was ‘websites’ (33.2%), followed by ‘professionals’ (23.8%), ‘acquaintances’ (20.9%), ‘print media’ (6.8%) and ‘TV/radio’ (3.4%). Patients who indicated websites showed the most severe pain and highest impact of headache, and accounted for 52.4% of those with cluster headaches. Development of websites concerning headache specialists would seem likely to increase doctor attendance rates for patients with primary headache.

On the interface magnetism of thin oxidized Co films: orbital and spin moments

An x-ray magnetic circular dichroism study of a polycrystalline Co/CoO bilayer is presented. Using both the chemical specificity and surface sensitivity in the core level techniques, we find that uncompensated Co(2+) spin moments participate in the remanent ferromagnetic response of the bilayer that has oxygen nearest neighbors. These are likely located at the Co/CoO interface. As intermixing of magnetic species is not present in Co/CoO, it is concluded that the observed interface moments are due to interface roughness. Given their direction, these moments appear to not directly correlate to the exchange bias in these bilayers.

[A new technique of aortic occlusion in patient with severe aortic calcification]

A 63-year-old woman with severe aortic valve insufficiency and bilateral subclavian artery occlusion underwent ascending aorta-to-biaxillary artery bypass and aortic valve replacement, simultaneously. Because of severe aortic calcification, a hand-made aortic occluder was utilized to prevent embolic stroke. We believe that the new technique of aortic occllusion might be very useful for patients with severe aortic calcification.

Unusual pressure-induced rupture of colonic volvulus in a patient with long-term corticosteroid therapy

Perforation due to colonic volvulus is typically considered to occur following ischemic necrosis of the intestinal wall. In this report, we report a rare case of sigmoid colon volvulus rupture caused by increasing intraluminal pressure without any sign of ischemia. The patient was an 88-year old Japanese male, who had been treated with 5 mg of oral prednisolone daily for 8 years. He consulted for severe abdominal pain that had lasted for three days. X-ray and computed tomography showed free peritoneal air, suggesting peritonitis. He was diagnosed with sigmoid colon volvulus perforation and underwent emergency surgery. Pathological examination showed no ischemic necrosis around the perforations in the resected intestine. As a result, we came to believe that the fragility of the colonic wall, caused by the patient's long-term use of corticosteroid, had lowered the threshold for pressure-induced colonic rupture.

Influence of ligand states on the relationship between orbital moment and magnetocrystalline anisotropy

The spin and orbital moments of Au/Co/Au trilayers grown on a W(110) single crystal substrate have been investigated by means of x-ray magnetic circular dichroism. Our findings suggest that the orbital moment of Co does not obtain a maximum value along the easy axis, in contrast with previous experience. This is attributed to the large spin-orbit interaction within the Au caps. Both second order perturbation theory and first principles calculations show how the magnetocrystalline anisotropy (MCA) is dramatically influenced by this effect, and how this leads to the fact that the orbital moment anisotropy is not proportional to the MCA.

Clinical and experimental features of MuSK antibody positive MG in Japan

We investigated the presence of antibodies (Abs) against muscle-specific tyrosine kinase (MuSK) in Japanese myasthenia gravis (MG) patients. MuSK Abs were found in 23 (27%) of 85 generalized seronegative MG (SNMG) patients but not in any of the ocular MG patients. MuSK Ab-positive patients were characterized as having female dominance (M:F, 5:18), age range at onset 18 to 72 (median 45) years old, and prominent oculobulbar symptoms (100%) with neck (57%) or respiratory (35%) muscle weakness. Limb muscle weakness was comparatively less severe (52%), thymoma absent. Most patients had good responses to simple plasma exchange and steroid therapy. MuSK IgG from all 18 patients was exclusively the IgG 4 subclass and bound mainly with the MuSK Ig 1-2 domain. Serial studies of 12 individuals showed a close correlation between the variation in MuSK Ab titers and MG clinical severity (P = 0.01 by Kruskal-Wallis). MuSK Ab titers were sharply decreased in patients who had a good response to early steroid therapy or simple plasma exchange, but there was no change, or a rapid increase on exacerbation after thymectomy. Measurement of MuSK Ab titers aids in the diagnosis of MG and the monitoring of clinical courses after treatment.

Induction of Detoxifying Enzyme by Sesquiterpenes Present inInula helenium

Our previous study showed that the methanolic extract of Inula helenium (elecampane) had the potential to induce detoxifying enzymes such as quinine reductase (QR) and glutathione S-transferase. In this study we further fractionated the methanolic extract into hexane-, dichloromethane-, butanol-, and water-soluble fractions according to polarity. The hexane fraction showed the highest QR-inducing activity and also induced glutathione S-transferase in a dose-dependent manner. Its potential to induce the reporter activity suggested an antioxidant response element-mediated mechanism of action in the induction of phase II detoxifying enzymes. Intraperitoneal injection of the hexane fraction of I. helenium into ICR mice caused a significant increase of QR activity in liver, kidney, small intestine, and stomach. Sesquiterpenes, isolated from the hexane fraction, appeared to be major components responsible for QR induction. Among the seven compounds tested in this study, alantolactone, isoalantolactone, and 5alpha-epoxyalantolactone significantly induced QR activity in both Hepa1c1c7 and BPRc1 cells. In conclusion, sesquiterpenes, including alantolactone, isoalantolactone and 5-epoxyalantolactone, present in I. helenium merit further evaluation as chemopreventive agents.

Clinical features of probable medication-overuse headache: a retrospective study in Japan

This study examined the clinical picture of probable medication-overuse headache (MOH) and the presence of any features peculiar to Japan. In a retrospective study of 47 patients, type of primary headache, type of medicine overused, method and result of withdrawal were investigated. Among the 47 patients, 80.9% had migraine only, and 85.1% overused combination medications. While 36 patients (76.6%) succeeded in withdrawal, five patients (10.6%) failed. One patient (2.1%) had not improved by 2 months after withdrawal and was diagnosed with chronic migraine and chronic tension-type headache without MOH. The remaining five patients (10.6%) dropped out. All dropout patients were recommended abrupt inpatient withdrawal, but chose abrupt outpatient withdrawal. As features peculiar to Japan, many patients with probable MOH overused combination analgesics, particularly females.

Overexpression of hRFI inhibits 5-fluorouracil-induced apoptosis in colorectal cancer cells via activation of NF-kappaB and upregulation of BCL-2 and BCL-XL

Resistance to apoptosis is one of the important determinants of resistance to 5-fluorouracil (5-FU) in colorectal cancer cells. Human Ring-Finger homologous to Inhibitor of apoptosis protein type (hRFI) is a newly discovered gene that has been shown to inhibit death receptor-mediated apoptosis in colorectal cancer cells. However, the molecular mechanism of the inhibition of apoptosis is presently unknown. In order to investigate the molecular function of hRFI in the regulation of 5-FU-induced apoptosis in colorectal cancer cells, HCT116 cells were stably transfected with hRFI or LacZ as a control. hRFI overexpression resulted in cellular resistance to 5-FU through an inhibition of the mitochondrial apoptotic pathway and specific upregulation of Bcl-2 and Bcl-XL. Futhermore, hRFI overexpression resulted in the activation of nuclear factor-kappaB (NF-kappaB). Inhibition of NF-kappaB effectively reversed the resistance to apoptosis as well as the upregulation of Bcl-2 and Bcl-XL in the hRFI transfectant, indicating that the activation of NF-kappaB is the key mechanism for all these findings. Overexpression of hRFI in SW480 and COLO320 colorectal cancer cells similarly resulted in resistance to 5-FU with the activation of NF-kappaB and upregulation of Bcl-2 and Bcl-XL. hRFI might be a novel therapeutic target for gene therapy in colorectal cancer.

Risk factors for lymph node and distant metastasis in colorectal carcinoids: An analysis of nationwide registry in Japan over 15 years

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Background: No global consensus has been established on the crucial determinants of metastasis in colorectal carcinoids. This study aims to determine the predictive factors for lymph node (LN) and distant metastasis, and to provide strategic model for the treatment of this uncommon disease. Methods: All patients diagnosed as carcinoids from 1984 to 1998 were extracted from the nationwide database, “Multi-Institutional Registry of Large-Bowel Cancer in Japan”, which covers almost 10% of all colorectal cancers in Japan. Risk factors for metastasis were analyzed among colorectal carcinoids undergoing surgery. Results: Among 90,057 cases of colorectal tumors registered from 1984 to 1998, a total of 345 cases of carciniods were identified. All cases were from the Asian population. The site distribution consisted of the ileum 3 (0.9%), appendix 8 (2.3%), colon 28 (8.2%) and rectum 304 (88.6%). Among colorectal carcinoids, a total of 263 cases undergoing surgery were eligible for the analysis (colon 23, rectum 240). Overall incidence of LN and distant metastasis were 29% and 7%, respectively. Univariate analysis showed that age>55, tumor size, tumor invasion≥T2, and lymphovascular invasion were associated with LN metastasis as well as distant metastasis. Multivariate analysis revealed that tumor size>10mm and lymphovascular invasion (LVI) were independently predictive of LN metastasis, while tumor size>20mm was a single risk factor for distant metastasis. Notably, tumors not larger than 10mm and without LVI exhibited no LN metastasis ( Table ). Conclusions: Tumors not larger than 10mm and without LVI could be curatively treated by endoscopic resection or transanal excision. However, tumors larger than 10mm or those with LVI should undergo radical surgery for LN dissection. Furthermore, tumors larger than 20mm carry a high risk for distant metastasis, and require close follow-up even without evident metastasis at the time of surgery.

[Table: see text]

No significant financial relationships to disclose.

Clinical features of ulcerative colitis-associated colorectal cancer in Japan: an analysis of 169 cases over 20 years

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Background: Development of colorectal cancer is a well-known long-term complication of ulcerative colitis (UC). However, specific clinical features of UC-associated colorectal cancer have been controversial mainly due to the small number of cases, especially in the Asian countries. This study aims to clarify the clinicopathological features of UC-associated colorectal cancer compared with non-UC-associated colorectal cancer in Japan, using a large nationwide database. Methods: All patients pathologically diagnosed as colorectal cancer from 1978 to 1998 were extracted from the nationwide database, “Multi-Institutional Registry of Large-Bowel Cancer in Japan”, which covers almost 10% of all colorectal cancers in Japan. Clinicopathological factors were compared between those associated with UC and the others. Survival analysis in each TNM stage was performed using the Kaplan-Meier method. Results: Among 108,536 cases of colorectal tumors registered from 1978 to 1998, a total of 169 cases of UC-associated colorectal cancers were identified. All cases were from the Asian population. UC-associated cases showed higher prevalence of females, younger age, higher incidence of multiple cancers, and higher incidence of mucinous adenocarcinomas. On the other hand, there were no differences in tumor sites, family history of colorectal cancer, lymph node metastasis, distant metastasis, TNM stage, and CEA level adjusted by TNM stage between the two groups. Survival analysis revealed poorer prognosis in UC-associated colorectal cancers at TNM stage 3. Conclusions: UC-associated colorectal cancer showed unique histological features compared with usual colorectal cancer. The survival of UC-associated colorectal cancer with lymph node metastasis was poorer than usual colorectal cancer, and therefore, intensive adjuvant therapy and close follow-up is needed after surgery in this patient group.

No significant financial relationships to disclose.

[Fontan completion after balloon angioplasty of multiple pulmonary artery stenosis in a child with pulmonary atresia with intact ventricular septum; report of a case]

A 5-year-old boy was referred to our institute for cardiac evaluation having been previously seen at another center. He had been diagnosed a pulmonary atresia with intact ventricular septum just after birth, and undergone Blalock-Taussig shunts. Although his central pulmonary artery pressure was high (mean pressure 26 mmHg) after bilateral Blalock-Taussig shunts, multiple peripheral pulmonary artery stenosis protected his pulmonary vascular bed from pressure load. We released the multiple pulmonary artery stenosis partly by catheter intervention and partly by surgical operation, and staged Fontan operation was completed. The surgery in combination with catheter therapies would expand the indication of Fontan-type operation, and it would contribute to the patients' postoperative prognosis.