Highly sensitive fluorescence detection of metastatic lymph nodes of gastric cancer with photo-oxidation of protoporphyrin IX.

BACKGROUND: The establishment of a precise and rapid method to detect metastatic lymph nodes (LNs) is essential to perform less invasive surgery with reduced gastrectomy along with reduced lymph node dissection. We herein describe a novel imaging strategy to detect 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence in excised LNs specifically with reduced effects of tissue autofluorescence based on photo-oxidation of PpIX. We applied the method in a clinical setting, and evaluated its feasibility. METHODS: To reduce the unfavorable effect of autofluorescence, we focused on photo-oxidation of PpIX: Following light irradiation, PpIX changes into another substance, photo-protoporphyrin, via an oxidative process, which has a different spectral peak, at 675 nm, whereas PpIX has its spectral peak at 635 nm. Based on the unique spectral alteration, fluorescence spectral imaging before and after light irradiation and subsequent originally-developed image processing was performed. Following in vitro study, we applied this method to a total of 662 excised LNs obtained from 30 gastric cancer patients administered 5-ALA preoperatively. RESULTS: Specific visualization of PpIX was achieved in in vitro study. The method allowed highly sensitive detection of metastatic LNs, with sensitivity of 91.9% and specificity of 90.8% in the in vivo clinical trial. Receiver operating characteristic analysis indicated high diagnostic accuracy, with the area under the curve of 0.926. CONCLUSIONS: We established a highly sensitive and specific 5-ALA-induced fluorescence imaging method applicable in clinical settings. The novel method has a potential to become a useful tool for intraoperative rapid diagnosis of LN metastasis.

Subjective response to neuroleptics: the effect of a questionnaire about neuroleptic side effects.

BACKGROUND: A patient's subjective response to neuroleptics is an important factor in pharmacotherapy of schizophrenia. In this study, we conducted an intervention to assess the effect of a questionnaire about neuroleptic side effects. We hypothesized that paying more attention to a patient's subjective distress associated with neuroleptic side effects would improve the patient's subjective response to neuroleptics. So we made a questionnaire about neuroleptic side effects, and used this questionnaire repeatedly in the usual clinical setting as an intervention. METHOD: We administered this study to 210 outpatients who met the following criteria: (1) diagnosis of schizophrenia or schizoaffective disorder as defined by DSM-IV and (2) no worsening of symptoms in the past 6 months. The patients were divided into the intervention and the control groups. Patients of the intervention group filled out the questionnaire four times during 6 months and were given routine clinical care. Patients of the control group had routine clinical care only. The 10-item Drug Attitude Inventory (DAI-10) was used to evaluate the patients' subjective responses to neuroleptics. RESULTS: After 6 months, the patients' subjective responses to neuroleptics assessed by the DAI-10 significantly improved in the intervention group (p<0.05 for within-group comparison). The most improved response was that the patients felt they were taking medications of their own free choice. CONCLUSION: Paying more attention to the patient's subjective distress associated with neuroleptic side effects may have encouraged patients to participate in pharmacotherapy on their own initiative. This study suggests that our 19-item questionnaire is a useful tool to improve a patient's subjective response to neuroleptics.

Malignant germ cell tumors: clinical characteristics, treatment, and outcome. A report from the study group for Pediatric Solid Malignant Tumors in the Kyushu Area, Japan.

PURPOSE: This study aims to assess the prognostic factors and optimal treatments for malignant germ cell tumors (MGCT) in childhood. METHODS: Among 117 MGCT, the clinical features were analyzed. Regarding the histology, there were 89 embryonal carcinomas, 13 dysgerminomas, 4 choriocarcinomas, and 11 others. The prognostic factors and treatments were assessed based on the 5-year survival rate. RESULTS: (1) Stage: 100% for stage I (n = 54), 75.0% for stage II (n = 4), 67.3% for stage III (n = 14), and 54.8% for stage IV (n = 33); Unknown: n = 12. (2) Primary site: 93.4% for the testis (n = 52), 86.7% for the ovary (n = 31), 56.9% for the sacrococcygeal (n = 21), and 60.6% for others (n = 12); unknown: n = 1. (3) Surgical intervention for primary tumor: 100% for stage I with a complete resection (n = 53), 78.4% for stage III, IV with a complete resection (n = 26), and 33.3% for stage III, IV with an incomplete resection (n = 21). (4) Type of chemotherapy for the stage III and IV: 83.9% for the PVB (cisplatin, vinblastin, bleomycin; n = 13), 66.7% for the VAC (vincristine, actinomycin D, cyclophosphamide; n = 6), and 47.1% for other regimens (n = 25). CONCLUSIONS: An early stage, a diagnosis under 1 year of age and a primary site in the gonads were favorable prognosis factors, whereas histologic findings of choriocarcinoma and liver or lung metastasis were unfavorable. Radical complete resection alone is a sufficient treatment for localized MGCT. The PVB regimen is optimal chemotherapy for advanced MGCT; however, high-risk cases still may require more aggressive treatment.

[Philadelphia chromosome-positive acute lymphoblastic leukemia preceded by acute pleuropericarditis].

A 69-year-old woman was admitted with sudden chest pain and high fever. Electrocardiography showed negative T waves in the precordial leads. Subsequently, pleural and pericardial effusion developed, but the symptoms and signs subsided without specific therapy. On day 31, fever, left shoulder pain and pleural effusion reappeared. 67Ga scintigraphy showed abnormal uptake in the chest and left shoulder. Blasts were detected in the peripheral blood on day 44, and in the pleural effusion and bone marrow on day 45. The blasts were positive for Philadelphia chromosome, CD10, CD19, CD33, CD34 and IgH-chain rearrangement and negative for myeloperoxidase. The clinical picture of the preceding pleuropericarditis was that of viral or idiopathic origin, but its relationship with acute lymphoblastic leukemia was unclear. Inflammatory chemokines in the pleural space may have induced invasion of the leukemic cells.

Possible use of transrectal power Doppler imaging as an indicator of microvascular density of prostate cancer.

OBJECTIVES: To reveal the possible use of transrectal power Doppler imaging (PDI) of the prostate in the assessment of the microvascular density (MVD) of cancer lesions. METHODS: In 22 patients with clinically organ-confined prostate cancer, PDI was performed before radical prostatectomy and the degree of vascularity of the cancer lesions as evaluated by PDI was compared with the MVD determined on the surgical specimens. The vascularity by PDI of each cancer lesion was graded on a scale of DS0 to DS2, according to the degree of Doppler signal accumulation. MVD was obtained using factor VIII immunohistochemistry. RESULTS: The vascularity of the PDI of 46 cancer lesions categorized 23 (50%), 10 (22%), and 13 (28%) cancer lesions as DS0, DS1, and DS2, respectively. Significant differences were found in the MVD between DS0 (46.6 +/- 26.8) and DS2 (89.0 +/- 18.1, P <0.005) lesions and between DS1 (50.9 +/- 25.4) and DS2 (P <0.001) lesions. The MVD of 30 cancer lesions in 13 patients without neoadjuvant therapy was significantly higher than that of the 16 lesions in 9 patients with therapy (70.2 +/- 28.2 versus 39.5 +/- 23.9, P <0.001). In the 13 patients without neoadjuvant therapy, the MVD of the DS2 lesions (89.1 +/- 18.9) was significantly higher than that of the DS0 lesions (59.3 +/- 32.5, P <0.01) and DS1 lesions (55.9 +/- 20.9, P <0.005). CONCLUSIONS: The semiquantitative assessment of Doppler flow signals using PDI appears to be of clinical value as an indicator of MVD.

Different regulation of connexin26 and ZO-1 in cochleas of developing rats and of guinea pigs with endolymphatic hydrops.

Using confocal microscopy and morphometry, we analyzed the expression of connexin26 (Cx26) and ZO-1 in rat cochlea during the postnatal period to elucidate spatiotemporal changes in gap junctions and tight junctions during auditory development. We also studied changes in these junctions in experimental endolymphatic hydrops in the guinea pig. In the adult rat cochlear lateral wall, Cx26 was detected in fibrocytes in the spiral ligament and in the basal cell layer of the stria vascularis, whereas ZO-1 was detected in the apical surfaces of marginal cells and in the basal cell layer. During postnatal development, Cx26 expression increased mainly in the spiral ligament, whereas ZO-1 expression increased in the basal cell layer. The morphometry of Cx26 showed a sigmoid time course with a rapid increase on postnatal day (PND) 14, whereas that of ZO-1 showed a marked increase on PND 7. In experimental endolymphatic hydrops, the expression of Cx26 significantly decreased, whereas there were no obvious changes in the expression of ZO-1. These results indicate that gap junctions and tight junctions in the cochlea increase in a different spatiotemporal manner during the development of auditory function and that gap junctions and tight junctions in the cochlea are differentially regulated in experimental endolymphatic hydrops. (J Histochem Cytochem 49:573-586, 2001)

Immunohistochemical localization of platelet-derived endothelial cell growth factor expression and its relation to angiogenesis in prostate.

OBJECTIVES: Tumor angiogenesis has been reported as a predictor for prognosis in patients with prostate cancer. The aim of this study was to determine the localization of one angiogenic factor, platelet-derived endothelial cell growth factor (PD-ECGF), in benign and malignant prostatic tissues and the correlation between PD-ECGF expression and microvessel density (MVD) in prostate cancer. METHODS: Forty cases of prostate cancer, 3 cases of benign prostatic hyperplasia, and 5 young autopsy cases without prostatic disease were processed with immunohistochemistry, using an anti-PD-ECGF antibody and anti-factor VIII-related antigen antibody. The PD-ECGF expression intensity and MVD were evaluated in each case. RESULTS: In the 40 cases with prostate cancer, the expression of PD-ECGF was noted in the stromal cells within cancer tissues in 80% of cases. Additionally, noncancerous glands next to cancer lesions were positive for PD-ECGF in 85% of cases. However, cancer cells were negative for PD-ECGF in all cases. In the 8 cases without cancer, both the prostatic glands and their surrounding stroma were positive for PD-ECGF only when they were accompanied by inflammation. There was a significant positive correlation (r = 0.636, P <0.001) between the intensity of PD-ECGF expression and MVD. MVD was significantly different when comparing the intensity of PD-ECGF expression of grade 0 versus grade 1 (P <0.05), grade 1 versus grade 2 (P <0.05), and grade 0 versus grade 2 (P <0.01). CONCLUSIONS: This study suggested that PD-ECGF expression in the stromal cells within cancer tissues might play an important role in tumor angiogenesis in prostate cancer.

Abnormalities in gap junctions and Ca2+ dynamics in cardiomyocytes at the border zone of myocardial infarcts.

Abnormalities in gap junction function and Ca2+ dynamics are believed to be important factors in arrhythmogenesis after myocardial infarction. To elucidate the relationship between changes in Ca2+ dynamics and gap junctions, we analyzed by real-time in situ Ca2+ imaging of fluo-3 loaded whole hearts the spatiotemporal occurrence of Ca2+ waves and the localization of connexin43 (Cx43) at the border zone of myocardial infarcts induced in the rat by coronary ligation. At early time points (2-4 hours postligation), different regions of the left ventricle showed distinct changes in cytosolic free Ca2+ concentrations [Ca2+]i. While some cardiomyocytes of infarcted regions exhibited high levels of resting fluo-3 fluorescence, at border zones frequent Ca2+ waves were observed. Some of the waves were abolished by spontaneous Ca2+ transients and others were not. Intact myocardium apart from infarcted regions exhibited homogenous Ca2+ transients. Confocal imaging of Cx43 and actin filaments in the rat heart fixed 2 hours after coronary ligation revealed that Cx43 was markedly decreased in the area of myocyte necrosis with contraction bands and in the neighboring myocardium. These results suggest that abnormal expression and function of gap junctions could be associated with Ca2+ waves at the border zone of myocardial infarcts, possibly through Ca2+ overload.

[Preferential infiltration of liver sinusoids in acute lymphoblastic leukemia].

We report a case of acute lymphoblastic leukemia (ALL) presenting as severe jaundice. The patient, a 59-year-old man, was found to have abnormal liver function, including an elevated total bilirubin level (13.5 mg/dl) with hepatosplenomegaly, but no detectable lymphadenopathy. A liver biopsy and bone marrow examination revealed a lymphoid neoplasm. Pathologic features included invasion of an abnormal clone into the sinusoidal region of the liver, diffuse bone marrow involvement (41.6% of all nucleated cells) and splenomegaly. Small numbers of malignant cells were also detected in the peripheral blood. B-cell markers, such as terminal deoxynucleotidyl transferase (TdT), CD10, CD19, CD20 and HLA-DR were positive, and CD2, CD3, CD4, CD5, CD7, CD8, kappa, lambda, cytoplasmic mu and myeloperoxidase were negative. Cytogenetic analysis detected hyperdiploidy. In this case, a dose-attenuated CHOP regimen attained complete remission. To date, preferential infiltration to liver sinusoids has been noted in hepatosplenic gamma/delta T-cell lymphoma, other NK/T-cell malignancies, and some cases of hairy cell leukemia. Severe jaundice due to preferential infiltration of leukemic cells into liver sinusoids is rather uncommon as a presenting feature of ALL.

Correlation of histological inflammation in needle biopsy specimens with serum prostate- specific antigen levels in men with negative biopsy for prostate cancer.

OBJECTIVES: To reveal the possible contribution of histological inflammation within the prostate to the abnormal elevation of serum prostate-specific antigen (PSA) levels in patients with needle biopsy negative for prostate cancer. METHODS: We reviewed negative needle biopsy specimens obtained in 93 patients. The degree of acute and chronic inflammation as evaluated histologically was compared with serum PSA levels in conjunction with age and prostate volume. RESULTS: Both age (P <0.01) and prostate volume (P <0.0001) correlated significantly with serum PSA levels and were significantly greater in patients with abnormal serum PSA levels (greater than 4.0 ng/mL) than in those with normal serum PSA levels (4.0 ng/mL or less) (P <0.01). The presence of histological inflammation within the prostate also correlated significantly with serum PSA levels. Multiple regression analysis demonstrated prostate volume to be the only independent determinant of serum PSA levels (P <0.01). In patients with a prostate volume larger than 25 mL, only prostate volume correlated significantly with serum PSA levels (P <0. 05). On the other hand, the degree of acute inflammation as represented by polymorphonuclear leukocyte infiltration was the only parameter correlating significantly with serum PSA levels (P <0.05) in patients with a prostate volume smaller than 25 mL. CONCLUSIONS: Histologically defined acute inflammation within the prostate is a significant contributor to elevated serum PSA levels, especially in patients with small prostates. In the assessment of needle biopsy results negative for prostate cancer, it might be helpful to evaluate the degree of histological inflammation, especially in terms of the necessity of subsequent repeated biopsies.

Three distinct types of Ca(2+) waves in Langendorff-perfused rat heart revealed by real-time confocal microscopy.

Although Ca(2+) waves in cardiac myocytes are regarded as arrhythmogenic substrates, their properties in the heart in situ are poorly understood. On the hypothesis that Ca(2+) waves in the heart behave diversely and some of them influence the cardiac function, we analyzed their incidence, propagation velocity, and intercellular propagation at the subepicardial myocardium of fluo 3-loaded rat whole hearts using real-time laser scanning confocal microscopy. We classified Ca(2+) waves into 3 types. In intact regions showing homogeneous Ca(2+) transients under sinus rhythm (2 mmol/L [Ca(2+)](o)), Ca(2+) waves did not occur. Under quiescence, the waves occurred sporadically (3.8 waves. min(-1) x cell(-1)), with a velocity of 84 microm/s, a decline half-time (t(1/2)) of 0.16 seconds, and rare intercellular propagation (propagation ratio <0.06) (sporadic wave). In contrast, in presumably Ca(2+)-overloaded regions showing higher fluorescent intensity (113% versus the intact regions), Ca(2+) waves occurred at 28 waves x min(-1) x cell(-1) under quiescence with a higher velocity (116 microm/s), longer decline time (t(1/2) = 0.41 second), and occasional intercellular propagation (propagation ratio = 0.23) (Ca(2+)-overloaded wave). In regions with much higher fluorescent intensity (124% versus the intact region), Ca(2+) waves occurred with a high incidence (133 waves x min(-1) x cell(-1)) and little intercellular propagation (agonal wave). We conclude that the spatiotemporal properties of Ca(2+) waves in the heart are diverse and modulated by the Ca(2+)-loading state. The sporadic waves would not affect cardiac function, but prevalent Ca(2+)-overloaded and agonal waves may induce contractile failure and arrhythmias.

Effect of the photocatalytic activity of TiO(2) on plasmid DNA.

We investigated the photodynamic DNA strand-breaking activity of TiO(2). A solution of super-coiled pBR 322 DNA was irradiated with 5 J/cm(2) of UVA in the presence of TiO(2) and the products were analyzed by using gel electrophoresis. The ratio of open-circular DNA to super-coiled circular DNA was calculated from the resulting peak areas as a DNA strand-breaking index (SBI). The SBI of anatase-structure TiO(2) (band gap=3.23 eV) was greater than that of rutile structure (band gap=3.06 eV), and the level of SBI correlated with the photocatalytic activity for degradation of 2-propanol. The inhibitory effects of active oxygen scavengers, including DMSO, glutathione and histidine, on the DNA strand-breaking activity were examined. All of the scavengers except ascorbic acid showed inhibitory effects, as did several polyhydric alcohols including mannitol, a well-known hydroxyl radical scavenger. These results suggest that the photodynamic DNA strand-breaking activity of TiO(2) is due to active oxygen species, especially hydroxyl radicals. Polyhydric alcohols showed an inverse correlation between the inhibitory effect on DNA strand-breaking activity and the octanol/water partition coefficient (logP).

Formation of cell junctions between grafted and host cardiomyocytes at the border zone of rat myocardial infarction.

BACKGROUND: Cardiomyocyte transplantation is an innovative strategy for the treatment of heart failure after myocardial infarction. Cell junctions show diverse temporal polarization toward intercalated disks during postnatal development and exhibit altered distribution in diseased hearts. To elucidate the formation of cell junctions between grafted and host cardiomyocytes at the border zone of myocardial infarction, the 3D distribution of cell junctions was examined using immunohistochemistry and confocal microscopy. METHODS AND RESULTS: Neonatal cardiomyocytes obtained from 3-day-old rats by collagenase digestion and Percoll density centrifugation were injected into the border zones of infarction sites 10 days after coronary ligation in adult rats. At 4 to 14 days after transplantation, hearts were harvested and processed by immunohistochemistry. Antibodies against connexin43, desmoplakin, and cadherin were used to analyze the distribution of gap junctions, desmosomes, and adherens junctions, respectively. Grafted cardiomyocytes were identified by immunohistochemistry for alpha-smooth muscle actin. Grafted cardiomyocytes tended to align parallel to the host cardiomyocytes. Connexin43, desmoplakin, and cadherin were localized between grafted cardiomyocytes themselves and between grafted and host cardiomyocytes. Semiquantitative analysis revealed that all junctions showed increasing polarization to longitudinal cell termini, especially at the border of grafted and host cardiomyocytes, as time advanced from 4 to 7 days after transplantation. CONCLUSIONS: These findings indicate that grafted cardiomyocytes foster electrical pathways with host counterparts through the gap junction and suggest that the environment in infarcted hearts could influence the localization of gap junctions, desmosomes, and adherens junctions.

Remodeling of cell-cell and cell-extracellular matrix interactions at the border zone of rat myocardial infarcts.

At the border zone of myocardial infarcts, surviving cardiomyocytes achieve drastic remodeling of cell-cell and cell-extracellular matrix interactions. Spatiotemporal changes in these interactions are likely related to each other and possibly have significant impact on cardiac function. To elucidate the changes, we conducted experimental infarction in rats and performed 3-dimensional analysis of the localization of gap junctions (connexin43), desmosomes (desmoplakin), adherens junctions (cadherin), and integrins (beta(1)-integrin) by immunoconfocal microscopy. After myocardial infarction, changes in the distribution of gap junctions, desmosomes, and adherens junctions showed a similar but nonidentical tendency. In the early phase, gap junctions almost disappeared at stumps (longitudinal edges of cardiomyocytes facing the infarct), and, although desmosomes and adherens junctions decreased, they still remained. In the healing phase, at stumps, connexin43, desmoplakin, and cadherin were closely associated between multiple cell processes originating from a single cardiomyocyte. Electron microscopy confirmed the presence of junctional complexes between the cell processes. beta(1)-Integrin at the cell process increased during the formation of papillary myotendinous junction-like structures. Abnormal localization of connexin43 was often accompanied by desmoplakin and cadherin on lateral surfaces of surviving cardiomyocytes. These findings suggested that remodeling of gap junction distribution was closely linked to changes in desmosomes and adherens junctions and that temporary formation of intracellular junctional complexes was an element of the remodeling of cell-cell and cell-extracellular matrix interactions after myocardial infarction. Moreover, the remodeling of the intercalated disk region at the myocardial interface with area of scar tissues was associated with the acquisition of extracellular matrix and beta(1)-integrin.

Functional morphology of the suprachiasmatic nucleus.

In mammals, the biological clock (circadian oscillator) is situated in the suprachiasmatic nucleus (SCN), a small bilaterally paired structure just above the optic chiasm. Circadian rhythms of sleep-wakefulness and hormone release disappear when the SCN is destroyed, and transplantation of fetal or neonatal SCN into an arrhythmic host restores rhythmicity. There are several kinds of peptide-synthesizing neurons in the SCN, with vasoactive intestinal peptide, arginine vasopressin, and somatostatine neurons being most prominent. Those peptides and their mRNA show diurnal rhythmicity and may or may not be affected by light stimuli. Major neuronal inputs from retinal ganglion cells as well as other inputs such as those from the lateral geniculate nucleus and raphe nucleus are very important for entrainment and shift of circadian rhythms. In this review, we describe morphological and functional interactions between neurons and glial elements and their development. We also consider the expression of immediate-early genes in the SCN after light stimulation during subjective night and their role in the mechanism of signal transduction. The reciprocal interaction between the SCN and melatonin, which is synthesized in the pineal body under the influence of polysynaptic inputs from the SCN, is also considered. Finally, morphological and functional characteristics of clock genes, particularly mPers, which are considered to promote circadian rhythm, are reviewed.

Detection and evaluation of asymptomatic myocarditis in schoolchildren: report of four cases.

STUDY OBJECTIVE: Data on the prevalence of myocarditis in children are limited. Autopsy studies have shown that myocarditis is often undiagnosed. We attempted to investigate the clinical features of asymptomatic myocarditis in four schoolchildren detected during a mass ECG screening in schoolchildren. DESIGN AND SETTING: To evaluate asymptomatic myocarditis, we clinically examined 12 schoolchildren who were referred to Shiga University of Medical Science Hospital, Otsu, Japan, because of abnormal ST or T waves detected during ECG screening. None of the 12 children had experienced any episodes suggesting cardiac disease or Kawasaki disease. Cardiac function and myocardial viability were assessed by two-dimensional echocardiography (2-DE), thallium-201 (201Tl) myocardial scintigraphy, and cardiac catheterization. Endomyocardial biopsy specimens were examined histologically. PATIENTS: Endomyocardial biopsy specimens revealed histologic evidence of myocarditis in 4 of the 12 children with abnormal ST or T waves. RESULTS: Abnormal tracer perfusion was observed on 201Tl myocardial scintigrams in these four children, but the results of coronary arteriography were normal. 2-DE showed left ventricular hypokinesis in one child and left ventricular enlargement in one of the four children with histologic evidence of myocarditis. A second endomyocardial biopsy specimen was obtained in two of four children, showing persistent myocarditis in one child. CONCLUSIONS: This type of screening program and indepth evaluation using 2-DE and 201Tl myocardial scintigraphy appear to be helpful in identifying children with myocarditis. The present histologic investigations suggested that even asymptomatic myocarditis might result in persistent heart damage.

Differential expression of gap junction proteins connexin26, 32, and 43 in normal and crush-injured rat sciatic nerves. Close relationship between connexin43 and occludin in the perineurium.

We immunohistochemically and morphometrically examined the expression of gap junction protein connexin (Cx) in normal and crush-injured rat sciatic nerves using confocal laser scanning microscopy. Cx26 was localized in the perineurium and Cx43 was present in the perineurium and the epineurium, whereas Cx32 was confined to the paranodal regions of the nodes of Ranvier. Double labeling for connexins and laminin revealed that Cx43 was localized in multiple layers of the perineurium, whereas Cx26 was confined to the innermost layer. Double labeling for connexins and a tight junction protein, occludin, showed that occludin frequently coexisted with Cx43 but existed separately from Cx26 in the perineurium. After crush injury, the pattern of normal Cx32 expression was initially lost but recovered, whereas Cx43 rapidly appeared in the endoneurium and its expression was subsequently attenuated. Although crush injury produced no apparent alteration in Cx43 and occludin in the perineurium, a rapid increase and a subsequent decrease in the frequency of Cx26-positive spots during nerve regeneration were shown by morphometric analysis. These results indicate that Cx26, Cx32, and Cx43 are expressed differently in various types of cells in peripheral nerves and that their expressions are differentially regulated after injury. The expression of connexins and occludin in the perineurium suggests that perineurial cells are not uniform in type and that the regulation of gap junctions and tight junctions is closely related in the perineurium.

Histiocyte reaction in rabbit femurs to UHMWPE, metal, and ceramic particles in different sizes.

To assess the histologic reaction caused by biomaterial particles in different sizes around the bone-implant interface, we examined ultra-high molecular weight polyethylene (UHMWPE, average diameter of 11 microm), UHMWPE (99 microm), cobalt-chromium alloy (Co-Cr, 3.9 microm), stainless steel (SUS316L, 3.9 microm), alumina ceramics (3.9 microm), titanium alloy (Ti, 3.5 microm), Co-Cr (0.03 microm), and Ti (0.03 microm). After the longitudinal groove on a polymethylmethacrylate plug was filled with one type of the particles, the plug was inserted into the medullar canal of the distal end of rabbit femurs, and tissue block was resected 4 and 12 weeks after the insertion. Histiocytes were markedly accumulated around the particles of UHMWPE (11 microm), Co-Cr (3.9 microm), SUS316L (3.9 microm), Co-Cr (0.03 microm), and titanium alloy (0.03 microm). Around the UHMWPE particles (99 microm), a slight histiocytic reaction and bone formation were observed. Particles of alumina ceramics (3.9 microm) and titanium alloy (3.5 microm) which were in phagocytosable sizes also had few histiocytic reactions. Statistically, the material difference was more strongly related to the histiocyte reaction than to the particle size and calculated total surface area of particles. Our findings demonstrate that particles of different biomaterials and in different sizes induce different foreign-body histological reactions.