Singlet oxygen-induced arrhythmias. Dose- and light-response studies for photoactivation of rose bengal in the rat heart

In a study of aerobically perfused rat hearts, the in situ photoactivation (530-590 nm) of rose bengal (a process that leads to the production of singlet oxygen and superoxide) has been shown to lead to the rapid development of electrocardiographic abnormalities and arrhythmias. With rose bengal concentrations of 1,000, 500, 250, 100, and 50 nmol/l (n = 6/group), photoactivation (3,600 lx) led to electrocardiographic changes (inversion of the T wave, Q-T prolongation, or both) after 3.8 +/- 0.9, 4.5 +/- 0.7, 11.8 +/- 2.1, 24.8 +/- 3.9, and 65.3 +/- 6.0 seconds), respectively; ventricular premature beats occurred in 100% of hearts after 0.5 +/- 0.2, 1.1 +/- 0.3, 2.2 +/- 0.7, 4.4 +/- 0.8, and 6.6 +/- 1.2 minutes, respectively. Ventricular tachycardia occurred in 83%, 83%, 83%, 67%, and 50% of hearts after 2.1 +/- 0.2, 2.1 +/- 0.4, 2.8 +/- 0.7, 5.7 +/- 2.0, and 11.2 +/- 1.9 minutes, respectively, and complete atrioventricular block in 100%, 100%, 100%, 100%, and 67% of hearts after 3.8 +/- 0.7, 6.5 +/- 1.0, 5.5 +/- 0.9, 13.8 +/- 1.0, and 14.1 +/- 0.9 minutes, respectively. With a fixed concentration (250 nmol/l) of rose bengal, similar light-response relations were observed. Photoactivation of rose bengal had no effect on heart rate but caused a transient (0-4 minutes) vasodilation followed by a progressive vasoconstriction. In further studies in which rose bengal was washed out for 10 minutes before photoactivation, several arrhythmias still developed, indicating that rose bengal binds strongly to tissue and acts as a cellular level rather than in the vascular compartment. To assess the reversibility of rose bengal-induced effects, hearts (n = 6/group) were perfused with rose bengal (250 nmol/l) for 1, 2, 4, 6, and 20 minutes followed by perfusion in the dark for 19, 18, 16, 14, and 0 minutes, respectively. During dark perfusion, the incidence of arrhythmias declined and any decrease in coronary flow was reversed. However, analysis of contents of adenosine triphosphate, creatine phosphate, lactate, and creatine kinase leakage indicated the occurrence of severe injury that did not abate on termination of photoactivation. Finally, although many arrhythmias developed before the onset of vasoconstriction, the reduction in flow with consequent ischemia was shown to exacerbate vulnerability to arrhythmias. In conclusion, short-lived reactive oxygen intermediates such as singlet oxygen and superoxide, which are produced during the photoactivation of rose bengal, can cause rapid and major damage to the heart and its function.     

Independent determinants of second derivative of the finger photoplethysmogram among various cardiovascular risk factors in middle-aged men.

The second derivative of the finger photoplethysmogram (SDPTG) has been used as a non-invasive examination for arterial stiffness. The present study sought to elucidate independent determinants of the SDPTG among various cardiovascular risk factors in middle-aged Japanese men. The SDPTG was obtained from the cuticle of the left-hand forefinger in 973 male workers (mean age: 44+/-6 years) during a medical checkup at a company. The SDPTG indices (b/a and d/a) were calculated from the height of the wave components. Multiple logistic regression analyses revealed that the independent determinants of an increased b/a (highest quartile of the b/a) were age (odds ratio [OR]: 1.12 per 1-year increase, 95% confidence interval [CI]: 1.09-1.15), hypertension (OR: 1.65, 95% CI: 1.03-2.65), dyslipidemia (OR: 1.51, 95% CI: 1.09-2.09), impaired fasting glucose/diabetes mellitus (OR: 2.43, 95% CI: 1.16-5.07), and a lack of regular exercise (OR: 2.00, 95% CI: 1.29-3.08). Similarly, independent determinants of a decreased d/a (lowest quartile of the d/a) were age (OR: 1.11 per 1-year increase, 95% CI: 1.08-1.14), hypertension (OR: 3.44, 95% CI: 2.20-5.38), and alcohol intake 6 or 7 days per week (OR: 2.70, 95% CI: 1.80-4.06). No independent association was observed between the SDPTG indices and blood leukocyte count or serum C-reactive protein levels. In conclusion, the SDPTG indices reflect arterial properties affected by several cardiovascular risk factors in middle-aged Japanese men. The association between inflammation and the SDPTG should be evaluated in further studies.     

Neurotized nevi of the oral mucosa: an immunohistochemical and ultrastructural analysis of nevic corpuscles

BACKGROUND: Nevic corpuscle (NC), a stacked lamellar structure reminiscent of Meissner corpuscle, is frequently observed in dermal melanocytic nevi. Although the heading 'neurotized' is classically used for these nevi, the exact neural nature of NC has been a topic of considerable debate. Neurotized nevi have received little attention in the dental literature, and there was no information on NC in oral melanocytic nevi. METHODS: Six cases of oral intramucosal nevi with a significant number of NC (two completely and four partially neurotized nevi) were examined immunohistochemically and ultrastructurally. RESULTS: NC was composed of closely piled laminar cells devoid of visible melanin. NC and associated spindle nevus cells were immunopositive for S-100 protein but negative for HMB-45, myelin basic protein and epithelial membrane antigen. Within NC, no reactivity for neurofilament protein, protein gene product 9.5 or peripherin was evident. Numerous CD34-positive dendritic cells were located between nevus cells and often encircled NC. Ultrastructurally, NC consisted of concentrically layered elongated cells with a slender lamellated cytoplasm rich in thin filaments and pinocytotic vesicles. Their cytoplasmic processes were focally covered by external basal lamina and continuous to spindle nevus cells. Occasional NC cells contained a few melanosomes. There was no interposed axon in NC. CONCLUSIONS: Despite the close resemblance to Meissner corpuscle, NC showed no axonal supply. NC cells lacked terminal Schwannian differentiation and appeared to be modified melanocytes with some perineurial ultrastructural characteristics. The presence of CD34-positive cells, presumably corresponding to endoneurial fibroblasts, further supports an organizational relationship of NC and peripheral nerve sheath elements.     

Presence of ghost cells and the Wnt signaling pathway in odontomas

BACKGROUND: Although it has been reported that ghost cells are present in odontomas, the generation mechanism of these cells is unclear. To evaluate the presence of ghost cells and involvement of the Wnt signaling pathway, we examined the expression of hard keratins, beta-catenin and Lef-1 in odontomas. METHODS: Sixty-nine cases of odontoma were examined immunohistochemically with the use of antibodies against human hair proteins, beta-catenin and Lef-1. RESULTS: Expression of hard keratins was found only in the cytoplasm of ghost cells in 46 (66.7%) of the 69 odontomas. Compound odontomas (78.8%) showed a higher incidence of ghost cells than complex odontomas (29.4%). Histopathologically, ghost cells were found within odontogenic epithelium adjacent to immature enamel and in the centre of Liesegang-ring-like calcified materials. Expression of beta-catenin and Lef-1 was observed in the cytoplasm and nucleus of odontogenic epithelial cells adjacent to the ghost cells in immature odontomas. CONCLUSION: These findings suggest that odontoma is a hard keratin-expressing tumor-like lesion, and that the Wnt signaling pathway may be involved in the formation of ghost cells in odontomas.     

A case of progressive muscular dystrophy with numerous arterioluminal vessels

A 48-year-old man had histologically demonstrated cardiac involvement associated with progressive muscular dystrophy. On coronary arteriography, numerous vascular communications between the coronary arteries and the left ventricular chamber were found. These vascular communications are considered to be the arterioluminal vessels. This is the first report of a case of progressive muscular dystrophy with numerous arterioluminal vessels.     

Stimulation of nonspecific resistance to infection induced by 6-O-acyl muramyl dipeptide analogs in mice.

The experimental system utilized in investigating the correlation between the chemical structures of muramyl peptides and their protective activities in the sepsis type of systemic infections caused by Escherichia coli was applied in evaluating the enhancement of resistance to infection induced by 32 synthetic glycopeptide analogs, including 6-O-acyl derivatives and 1-alpha-O-benzyl derivatives of muramyl dipeptide (N-acetyl muramyl-L-alanyl-D-isoglutamine). In assessing the 6-O-acyl derivatives of muramyl dipeptide, we found that the degree of protective activity was attributable to the kinds of fatty acids introduced. Acylation of the 6-hydroxy group on the muramic acid moiety in muramyl dipeptide with natural mycolic acid or a synthetic fatty acid possessing either an alpha-branched or an alpha-branched, beta-hydroxylated group resulted in a decrease in or a disappearance of the protective activity of muramyl dipeptide. Acylation with a normal fatty acid or an iso fatty acid resulted in a retention or enhancement of muramyl dipeptide activity. The activity of acylated derivatives containing linear fatty acids was stimulated by increasing the chain length up to 18 carbon atoms. The highest degree of protective activity occurred with the derivatives acylated with straight-chain fatty acids, particularly with the derivatives acylated with palmitic acid and arachidic acid. Benzylation of the 1-hydroxy group of muramyl dipeptide resulted in a decrease in or a loss of protective activity.     

Antigen-induced elevation of immunoreactive endothelin-1 (ET-1) levels in ovalbumin-sensitized guinea pig airway tissue

Changes in the immunoreactive ET-1 levels during the anaphylactic reaction of airway tissue from ovalbumin-sensitized guinea pigs were investigated. ET-1-immunoreactivity (ET-IR) was detected in the epithelial and smooth muscle layers of tracheal sections from normal guinea pigs and it was enhanced slightly by phosphoramidon (1 microM) treatment. The ET-IR level of the epithelial layer of ovalbumin-treated tissue from actively sensitized animals was slightly higher than that from normal animals, but it was enhanced markedly by phosphoramidon (1 microM) treatment. Furthermore, the mean ET-IR level of homogenates of antigen-treated tracheal tissues from sensitized guinea pigs (22.8 +/- 1.55 fmol mg-1 protein, n = 5) was significantly higher than the corresponding normal level (12.3 +/- 1.21 fmol mg-1 protein, n = 5). These results suggest that increased epithelial airway ET-1 levels contribute to the anaphylactic reaction of guinea pig airways.     

Activation of protein kinase C induces internalization of the GABA(C) receptors expressed in Xenopus oocytes

In a previous study, we showed that the protein kinase C (PKC) activator 4beta-phorbol 12-myristate 13-acetate (PMA) inhibited the gamma-aminobutyric acid (GABA)-gated currents in Xenopus oocytes expressing human rho1 GABA(C) receptors. To investigate whether the inhibition of currents was due to a decrease in efficacy or in the potency of rho1 GABA(C) receptor, concentration-response curves for GABA were compared before and after PMA treatment. The EC50 concentrations of GABA obtained during the maximally inhibited period were not statistically different from the concentrations obtained before PMA treatment (1.74 +/- 0.33 and 1.45 +/- 0.28 microM, respectively). These results indicate that the inhibition depends on a change in number or conductance of active receptor channels, but not on a change in affinity for GABA. To allow histochemical detection of rho1 GABA(C) receptors, we constructed a receptor tagged at the C-terminal position with human c-myc epitope. Electrophysiologically, the tagged receptors showed almost the same sensitivities for GABA and PMA as those of wild-type rho1 GABA(C) receptors. Immunohistochemistry with anti-myc antibody detected a dense concentration of tagged receptors at the surface area of Xenopus oocytes. Transient exposure to PMA reduced the density of immunofluorescence at the surface area and increased it in the subsurface area. These results suggest that the stimulation of protein kinase C leads to internalization of rho1 GABA(C) receptors expressed in Xenopus oocytes.     

Cordyceps militaris Fruit Body Extract Decreases Testosterone Catabolism and Testosterone-Stimulated Prostate Hypertrophy

The androgens testosterone and dihydrotestosterone (DHT) are essential for a variety of systemic functions in mature males. Alteration of these hormones results in late-onset hypogonadism (LOH) and benign prostate hyperplasia (BPH). The fruit bodies of fungi of the genus Cordyceps have been regarded as folk medicine or health food with tonic and antifatigue effects. The extract from the fruit body of Cordyceps militaris parasitizing Samia cynthia ricini (CM) was evaluated as a novel-candidate natural product for ameliorating male andropause symptoms. To explore the effects of CM on LOH and BPH, CM was applied to rat models and cultured testicular cells and prostate cells. The concentrations of androgens in the serum and culture media were determined by ELISA. Expression of steroidogenic enzymes and androgen-related genes was evaluated by qPCR, and prostatic cell proliferation was assessed with the cell-viability assay. CM maintained the serum levels of testosterone and DHT, but inhibited testosterone-induced prostate hypertrophy. CM also increased the secretion of testosterone and DHT by primary testicular cells, with no changes in the mRNA expression of steroidogenic enzymes, but decreased the growth of prostatic cell lines. Our data suggest that CM could improve both LOH and BPH in males.     

Axillary management based on American college of surgeons oncology group Z0011 criteria makes it possible to omit intraoperative diagnosis of sentinel lymph nodes in early breast cancer patients

The ACOSOG Z0011 trial has resulted in the omission of axillary lymph node dissection (ALND) in early breast cancer patients with one or two metastatic sentinel lymph nodes (SLNs). There has been increasing interest in the necessity of intraoperative assessment of SLNs in patients treated based on the Z0011 criteria. We evaluated the utility of intraoperative assessment in these eligible patients. A total of 1396 patients were treated following the Z0011 criteria from April 2012 to December 2019. We examined the proportion and clinicopathological features of patients who underwent ALND due to three or more metastatic SLNs and the sensitivity of intraoperative assessment. Only 16 (1.1%) patients had three or more metastatic SLNs diagnosed by intraoperative assessment, and they immediately underwent ALND. Of the clinicopathological factors, high clinical tumor stage (p = 0.002) and high Ki-67 labeling index value (p = 0.056) were more likely to be associated with the presence of three or more metastatic SLNs. The major independent risk factor for three or more metastatic SLNs was high clinical tumor stage (OR 3.94 [95% CI 1.42–11.0]; p = 0.009). Intraoperative assessment had low sensitivity (70.5%) and a high false-negative rate (29.5%) in detecting SLN metastases. The main finding of our study was the small proportion of patients who required ALND due to three or more metastatic SLNs according to the Z0011 criteria. The Z0011 strategy enables intraoperative assessment of SLNs to be omitted in early breast cancer patients.