Biomedical subjects
Publications and source records attributed to T Harada.
A delayed procedure was performed in flow-through venous flaps made in rabbits' ears. Compared with undelayed venous flaps, the delayed flaps at 7, 14 and 21 days after delay showed a distinct increase of survival area. This effect increased with the delay period.
Tendon adhesion occurring after major replantation can be severe and extensive due to the nature of the trauma, ischaemia, prolonged oedema and/or infection. Therefore there is a high possibility of re-adhesion after tenolysis. In two cases of tenolysis after forearm replantation omentum was used as gliding material and good results were obtained.
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BACKGROUND: Gastric epithelium is exposed to toxic, reactive oxygen species generated within the lumen. The present study examined the role of cellular iron and superoxide (O2-) in mediating hydrogen peroxide (H2O2)-induced damage to cultured gastric mucosal cells. METHODS: H2O2 was generated by glucose oxidase acting on b-D(+)glucose. Cytotoxicity was assessed by 51Cr release from prelabeled cells. RESULTS: Deferoxamine (a chelator of Fe3+) prevented injury induced by H2O2, whether present before or during H2O2 production. In contrast, whereas the presence of phenanthroline (a chelator of Fe2+) during the cytotoxicity assay prevented damage, prior treatment with the agent did not; this suggested that cellular Fe3+ reduced to Fe2+ upon exposure to H2O2 is responsible for damage. Neither extracellular superoxide dismutase nor inhibitors of xanthine oxidase (a possible source of cellular O2- production) protected against H2O2. Further, protection by iron chelators was not associated with modulation of endogenous antioxidants. CONCLUSIONS: Deferoxamine and phenanthroline protect cells from H2O2 by chelating stored iron (Fe3+) or reduced iron (Fe2+), respectively. Reduction of cellular Fe3+ appears to be a prerequisite for mediation of damage, but this reduction is independent of extracellular O2- or cellular xanthine oxidase-derived O2-.
The vitamin A status of 19 patients with corrected biliary atresia was examined. They had been receiving 5,000 IU of oral vitamin A daily postoperatively. Plasma vitamin A levels in the nonjaundiced group were almost within normal range, whereas those in the jaundiced group were significantly low compared with the controls. In the oral vitamin A tolerance test, plasma vitamin A levels increased from 33.1 +/- 11.8 to 215.4 +/- 100.7 micrograms/dL in the nonjaundiced group, and from 23.1 +/- 10.3 to 209.8 +/- 154.2 micrograms/dL in the slightly jaundiced group, at 4 hours after the administration of vitamin A, showing no difference between both group and control. In the severely jaundiced group, plasma vitamin A levels increased from 13.5 +/- 3.5 to 30.0 +/- 14.6 micrograms/dL, a significantly smaller increase compared with controls. However, liver vitamin A levels were greater than 20 micrograms/g liver in all patients, irrespective of the presence of jaundice. This study suggested that nutritional support to facilitate the synthesis of retinol-binding protein may be an important factor in addition to vitamin A supplementation.
BACKGROUND: Parapsoriasis en plaques (large-plaque type) is a premalignant condition capable of developing into cutaneous T-cell lymphoma (CTCL). However, it is not known whether the early stage of CTCL can be distinguished from parapsoriasis en plaques. OBJECTIVE: Our purpose was to determine whether parapsoriasis en plaques can develop into CTCL. METHODS: The clinical appearance, histopathologic features, immunophenotype, DNA rearrangements, and clinical course were analyzed in 20 cases. RESULTS: T-cell receptor beta-chain gene rearrangement was detected in four of the 20 cases. No clinical, histopathologic, or immunohistochemical differences were found between patients with and without gene rearrangement. CONCLUSION: The early stage of CTCL cannot be differentiated from parapsoriasis en plaques by clinical features, histopathologic characteristics, or immunophenotype. Patients with parapsoriasis en plaques exhibit heterogeneous findings, which may include monoclonal proliferation. Patients with long-standing parapsoriasis-like lesions resistant to conventional treatment require careful monitoring for the possible development of cutaneous lymphoma.
We describe an 82-year-old man with CD8+ lymphoepithelioid lymphoma localized to the skin. The skin lesion had been present for 18 years. Histologically there was a dense infiltrate that consisted of atypical lymphoid cells and large epithelioid cells, thereby resembling the so-called Lennert's lymphoma. Local radiotherapy proved effective in reducing the size of the tumor. To the best of our knowledge, this is the first report of primary lymphoepithelioid lymphoma of the skin.
The pharmacologic potential of selective alpha 2 adrenergic agents in modulating vesicourethral function was evaluated in urethane-anesthetized and conscious rats. The bladder was exposed through a midline incision and intubated via a cystostomy to measure pressure. The bladder was filled with saline at 0.05 ml./min. In six animals intravenous dexmedetomidine 0.6 micrograms./kg. followed by 2 micrograms./kg. was given. In another six rats the infusion was made with atipamezole at the same concentration. The parameters obtained were pressure/volume during cystometry, detrusor voiding pressures, and evidence of urine leakage. Conscious rats were placed in a restrainer outfitted with a voided volume sensor and a data recorder. The animals were divided in three groups. In controls, group I (n = 8), the animals were injected with a subcutaneous (SC) load of 5 ml. saline in which furosemide 10.0 mg./kg. was added. In group II (n = 6), dexmedetomidine was added in group III (n = 6), atipamezole was added. Parameters obtained were volume per micturition, latency, frequency of micturition, and patterns of micturition (such as dribbling), and total volume produced after a three hour recording. Values are expressed as mean +/- standard deviation. The results show that in an anesthetized preparation, the alpha 2 agonist dexmedetomidine produced inhibitory effects on the volume evoked micturition reflex (VEMR) at a dose level of 2.0 micrograms./kg. There was a significant decrease in peak pressure from 26.4 +/- 3.6 to 6.8 +/- 2.1 cm. H2O (p < 0.01). Urine leakage was observed at the external meatus. Atipamezole, the alpha 2 agonist, gradually increased bladder baseline pressure and inhibited VEMR. At a critical pressure there was continuous leakage from the external meatus. There was a significant elevation of baseline bladder pressure by atipamezole from 6.3 +/- 1.7 to 29.8 +/- 4.6 cm. H2O (p < 0.005). In conscious rats, the alpha 2 agonist produced urinary dribbling at approximately 20 minutes after SC injection, while the antagonists produced delayed dribbling 70 minutes after SC injection. Leakage occurred in 3 of 6 rats at a dose of 10 micrograms./kg. of atipamezole and in 5 of 6 rats at a dose of 30 micrograms./kg. The alpha 2 agonist caused a diuretic effect and a dose-dependent increase in the frequency of voiding (p < 0.05), while the antagonist decreased the frequency of voiding. Bladder capacity was decreased with the alpha 2 agonist while the antagonist increased capacity.
Superoxide anion (O2-) generation levels in peripheral blood neutrophils stimulated by N-formyl-methionyl-leucyl-phenylalanine were evaluated in patients with oromaxillary cancer. The levels in patients with benign tumors were nearly equal to those of normal controls. Patients with squamous cell carcinoma in stage I and II had levels that were widely distributed. On the other hand, O2- generation levels in the advanced stages (III and IV) of squamous cell carcinoma showed lower levels than those of controls (P < .01). All cases of oromaxillary carcinoma showed low levels of O2- generation within 1 month before death compared with controls (P < .01). The generation levels of O2- in the posttreatment period were lower than those before combination cancer treatments. Among cancer treatments such as chemotherapy, surgery, and irradiation, the latter had the strongest effects on O2- generation. These results suggest that low levels of O2- generation by peripheral blood neutrophils may reflect a worsening status of oromaxillary cancer patients.
A malignant epithelioid schwannoma occurred on the right second toe of a 30-year-old Japanese man. It was a firm, flesh-colored, benign-appearing nodule and measured 13 x 9 mm in diameter and 6 mm in height. To our knowledge, this is the first case of malignant epithelioid schwannoma occurring on the toe. Histopathology was characterized by a circumscribed nodule in the dermis that predominantly consisted of atypical large epithelioid cells with some spindle cells whose proliferation was similar to that of the Verocay bodies seen in ordinary schwannoma. Fontana-Masson staining demonstrated no melanin pigment in the tumor at the light microscopic level. The eosinophilic cytoplasm contained abundant glycogen and was positive for S-100 protein and HMB-45, as usually seen in melanomas. Electron microscopy revealed that there was an abundance of long-spacing collagen in the extracellular matrix, and the cells contained numerous dense-cored granules. But no definite melanosomes were observed in any stage. As far as we are aware, this is the first case of a malignant epithelioid schwannoma showing HMB-45 positivity.
Dermis-fat grafts were performed on 7 patients at the time of parotidectomy to prevent Frey's syndrome and the characteristic concave deformity. Only 1 patient demonstrated postoperative Frey's syndrome, and 1 demonstrated a slightly concave deformity due to fat absorption. Although other barrier materials have been reported to achieve success in preventing gustatory sweating, our method simultaneously corrects the associated deformity of facial contour as well.
A case of primary adenosquamous carcinoma of the liver, a rare type of tumour, is reported. The aetiology and histopathology of this tumour are discussed.
INTRODUCTION: During extrastimulation or entrainment of orthodromic atrioventricular (AV) reciprocating tachycardia (ORT), the atrium-His (AH) interval as measured at the His-bundle recording site is expected to lengthen due to extrastimulation-dependent or pacing rate-dependent slowing of AV nodal conduction by impulses that penetrate the tachycardia circuit. We report 6 patients in whom the AH interval "paradoxically" shortened during ORT in response to extrastimulation and rapid pacing from the proximal coronary sinus. METHODS AND RESULTS: Accessory pathway location was right anterior (1 patient), right anteroseptal (1 patient), and left anterior (4 patients). Cycle length of ORT was stable (variation < or = 5 msec) and ranged from 325 to 410 msec. During ORT, extrastimulation and rapid pacing were performed from the proximal coronary sinus and the right atrium. Extrastimulation from the proximal coronary sinus late in diastole caused significant shortening of AH interval in all patients by a mean of 18 +/- 3 msec (range 15 to 20 msec). AH shortening was demonstrated without a change of either the timing or morphologic appearance of the low septal right atrium at the His-bundle recording site. This phenomenon was not observed during right atrial extrastimulation. Rapid pacing from the proximal coronary sinus at cycle lengths of 305 to 390 msec (i.e., 15 to 20 msec shorter than the cycle length of each ORT) again demonstrated shortening of AH interval in all patients by a mean of 15 +/- 3 msec (range 10 to 20 msec). By contrast, rapid pacing from the right atrium demonstrated classical AH prolongation at any paced cycle length. CONCLUSION: AH shortening without a change of either the timing or morphologic appearance of the low septal right atrium at the His-bundle recording site confirms the existence of a distinct posterior atrial input to the AV node. In this setting low septal right atrial activation is not requisite for AV nodal conduction. Whether activation of the low septal right atrium is essential for, or contributes to, AV nodal conduction of atrial impulses from locations other than the proximal coronary sinus needs to be determined.
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BACKGROUND: Persistent inappropriate sinus tachycardia has been reported as a complication after radiofrequency (RF) ablation of the fast atrioventricular (AV) nodal pathway. The purpose of this study was to evaluate the prevalence of this complication and its mechanism using heart rate variability analysis. METHODS AND RESULTS: Time and frequency domain analysis of heart rate was performed in the electrophysiology laboratory immediately before and immediately after RF ablation in 64 patients with supraventricular tachycardia. Ablation targets in these 64 patients included the fast AV nodal pathway (n = 3), the slow AV nodal pathway (n = 14), a posteroseptal accessory pathway (n = 23), and a left lateral accessory pathway (n = 24). A control group of 21 patients undergoing diagnostic study but not ablation underwent identical analysis immediately before and at the conclusion of their procedure. Patients undergoing ablation also had time and frequency domain analysis performed on ambulatory 24-hour Holter tapes recorded before ablation and at 1 day, 1 month, and 6 months after ablation. Compared with preablation values, time domain analysis immediately after ablation revealed a significant increase in mean heart rate and significant reductions in heart rate variability expressed as SD, MSSD, and PNN50 in patients undergoing AV nodal modification or posteroseptal accessory pathway ablation. Frequency domain analysis revealed marked attenuation of high frequency (0.15 to 0.40 Hz) components, indicating parasympathetic denervation. These acute changes were not seen after ablation of left lateral accessory pathways or after diagnostic study without ablation. Time and frequency domain analysis of 24-hour ambulatory Holter monitors performed serially after ablation revealed resolution of abnormalities of heart rate and of heart rate variability 1 to 6 months after ablation, with reappearance of the high frequency parasympathetic component suggestive of reinnervation. CONCLUSIONS: RF ablation in the anterior, mid, and posterior regions of the low interatrial septum may disrupt preganglionic or postganglionic parasympathetic fibers located in these regions that are destined to innervate the sinus node. Such fibers become more scarce along the left AV groove with increasing distance from the posteroseptal space. Parasympathetic denervation may be one mechanism for persistent inappropriate sinus tachycardia after RF ablation.
We attempted to determine the relationship of nasal polyps to histamine (HA) metabolism. Compared to that in allergy-related nasal polyps and infection-related nasal polyps, the level of HA in aspirin-induced asthma-related polyps was significantly lower. Large differences between the groups were not observed in HA-synthesizing enzyme activity, but degradative enzyme activity was much higher in aspirin-induced asthma-related polyps than in other types of nasal polyps tested. These findings suggest the possibility that the amount of HA in polyps associated with aspirin-induced asthma was less because of greatly enhanced degradation. We found, in addition, that in nasal tissues such as polyps, histamine-N-methyl transferase, rather than histaminase, was the principal degradative enzyme.
Carcinogenic potential of ethylenethiourea (ETU) in combination with sodium nitrite was investigated in ICR mice of both sexes. Groups of 30 males and 30 females each were given 10 weekly oral administrations of ETU and sodium nitrite with the following combinations of dosing (ETU vs sodium nitrite, mg/kg/wk): 0 vs 0, 100 vs 0, 0 vs 70, 25 vs 17.5, 50 vs 35, and 100 vs 70. Thereafter, the animals were allowed to live without treatment up to 18 mo after the first administration. Concurrent administration of ETU and sodium nitrite caused earlier development of tumors and/or dose-dependent increases in the incidences of tumors in the lymphatic tissue, lung, forestomach, Harderian gland, and uterus, whereas treatment with either ETU or sodium nitrite failed to show carcinogenic activity. In addition, carcinomas in the forestomach and uterine horn were limited to mice receiving concurrent administrations of ETU and sodium nitrite. These results indicate that ETU is most probably converted in vivo into N-nitroso ETU and that the N-nitroso ETU has a greater carcinogenic potential in mice than ETU alone.
We investigated the roles of the endothelium in the hypoxic responses of the isolated main pulmonary artery (PA) in the rat. Hypoxia was induced by gassing an organ chamber with 95% N2 + 5% CO2 (PO2 = 34.6 +/- 3.1 Torr) instead of 16% O2 + 5% CO2 + balance N2 (PO2 = 92.8 +/- 3.0 Torr). Vascular rings were precontracted with 2 x 10(-8) M phenylephrine. A transient hypoxic contraction and a subsequent relaxation were observed in the endothelium-intact rings. The hypoxic contraction was reduced in the endothelium-denuded rings. In contrast, there were no significant differences between the hypoxic relaxation in the endothelium-intact and endothelium-denuded rings. Inhibitors of endothelium-derived relaxing factor (EDRF) activity, 2 x 10(-6) M NG-monomethyl-L-arginine (L-NMMA) and 10(-6) M methylene blue, produced 53% and 66% reductions in hypoxic contraction, respectively, Furthermore, the amount of cyclic GMP in the endothelium-intact PA rings which had been precontracted with phenylephrine decreased from 2.10 +/- 0.45 pmol/mg protein during normoxia to 0.90 +/- 0.18 pmol/mg protein during hypoxia. Indomethacin and OKY-046 did not influence hypoxic contraction or relaxation. These results suggest that hypoxic contraction of the isolated pulmonary artery in the rat is partially induced by inhibition of the release of EDRF.