Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 145 records · Page 8Linked to original sources

PubMed1999

Medullary dorsal horn neuronal activity in rats with persistent temporomandibular joint and perioral inflammation.

Studies at spinal levels indicate that peripheral tissue or nerve injury induces a state of hyperexcitability of spinal dorsal horn neurons that participates in the development of persistent pain and hyperalgesia. It has not been demonstrated that persistent injury in the orofacial region leads to a similar state of central hyperexcitability in the trigeminal system. The purpose of the present study was to conduct a parametric analysis of the response properties of nociceptive and nonnociceptive neurons in trigeminal nucleus caudalis (medullary dorsal horn, MDH) in a rat model of persistent orofacial inflammation. Neurons were recorded extracellularly and classified as low-threshold mechanoreceptive (LTM, n = 49), wide dynamic range (WDR, n = 82), and nociceptive-specific (NS, n = 11) neurons according to their response properties to mechanical stimuli applied to their cutaneous receptive fields (RFs). The inflammation was induced 24 h before the recordings by injecting complete Freund's adjuvant (CFA) into the temporomandibular joint (TMJ) capsule or the perioral (PO) skin. The mean areas of the high-threshold RFs of WDR neurons in TMJ (8.66 +/- 0.61 cm(2), n = 25) and PO (5.61 +/- 2.07 cm(2), n = 25) inflamed rats were significantly larger than those in naive rats (1.10 +/- 0. 16 cm(2), n = 32). The mean RF size in TMJ-inflamed rats also was significantly larger than that in PO-inflamed rats (P < 0.01). Furthermore the mean area of the RFs of NS neurons (3.74 +/- 1.44 cm(2), n = 5) was significantly larger in TMJ inflamed rats as compared with naive rats (0.4 +/- 0.09 cm(2), n = 3) (P < 0.05). The background activity in the TMJ- and PO-inflamed rats was generally greater in WDR and NS neurons, but less in LTM neurons, when compared with naive rats. The responses of WDR neurons to noxious mechanical stimuli were increased significantly in TMJ-inflamed rats (P < 0.05) as compared with naive rats. WDR neuronal responses to mechanical stimulation also were increased in PO-inflamed rats but to a lesser extent than in TMJ-inflamed rats. The injection of CFA into the TMJ or PO skin resulted in reduced responses of LTM neurons to mechanical stimuli. The responses of MDH nociceptive neurons to 48-55 degrees C heating were greater in inflamed rats as compared with naive rats. A subpopulation of WDR neurons recorded from TMJ (n = 4 of 10)- or PO (n = 3 of 13)-injected rats responded to cooling in addition to heating of the RFs but did not grade their responses with changes in stimulus intensity. These results indicate that persistent orofacial inflammation produced hyperexcitability of MDH nociceptive neurons. TMJ inflammation resulted in more robust changes in MDH nociceptive neurons as compared with PO inflammation, consistent with previous studies of increased inflammation, increased MDH Fos-protein expression, and increased MDH preprodynorphin mRNA expression in this deep tissue orofacial model of pain and hyperalgesia. The inflammation-induced MDH hyperexcitability may contribute to mechanisms of persistent pain associated with orofacial deep tissue painful conditions.

Animals↗

PubMed1999

Behavior of jaw muscle spindle afferents during cortically induced rhythmic jaw movements in the anesthetized rabbit.

The regulation by muscle spindles of jaw-closing muscle activity during mastication was evaluated in anesthetized rabbits. Simultaneous records were made of the discharges of muscle spindle units in the mesencephalic trigeminal nucleus, masseter and digastric muscle activity (electromyogram [EMG]), and jaw-movement parameters during cortically induced rhythmic jaw movements. One of three test strips of polyurethane foam, each of a different hardness, was inserted between the opposing molars during the jaw movements. The induced rhythmic jaw movements were crescent shaped and were divided into three phases: jaw-opening, jaw-closing, and power. The firing rate of muscle spindle units during each phase increased after strip application, with a tendency for the spindle discharge to be continuous throughout the entire chewing cycle. However, although the firing rate did not change during the jaw-opening and jaw-closing phases when the strip hardness was altered, the firing rate during the power phase increased in a hardness-dependent manner. In addition, the integrated EMG activity, the duration of the masseteric bursts, and the minimum gape increased with strip hardness. Spindle discharge during the power phase correlated with jaw-closing muscle activity, implying that the change in jaw-closing muscle activity associated with strip hardness was caused by increased spindle discharge produced through insertion of a test strip. The increased firing rate during the other two phases may be involved in a long-latency spindle feedback. This could contribute to matching the spatiotemporal pattern of the central pattern generator to that of the moving jaw.

Afferent Pathways↗

PubMed1999

Influence of clenching intensity on bite force balance, occlusal contact area, and average bite pressure.

It has been difficult for investigators to simultaneously and reliably evaluate bite force in the intercuspal position with the area and location of occlusal contacts. This study was designed to investigate the variations in these parameters with respect to two factors: three levels of clenching and the preferred chewing side. Human subjects with normal occlusion were examined with a recently developed system (Dental Prescale Occluzer, Fuji Film, Tokyo, Japan). The three levels of clenching intensity were assessed by masseteric EMG activity and included the maximum voluntary contraction, and 30% and 60% of the maximum. The results indicated that the bite force and occlusal contact area on the whole dental arch increased with clenching intensity. In contrast, the average bite pressure, obtained by dividing the bite force by the contact area, remained unchanged regardless of the clenching intensity. As the clenching intensity increased, the medio-lateral position of the bite force balancing point shifted significantly (P<0.01) from the preferred chewing side toward the midline. The antero-posterior position remained stable in a range between the distal third of the first molar and the mesial third of the second molar. The bite force and occlusal contact area, which were mainly on the molars, increased with the clenching intensity, whereas the proportions of these two variables on each upper tooth usually did not change significantly. The exception was the second molar on the non-preferred chewing side. When comparisons were made between pairs of specific upper teeth of same name, usually no significant difference was found in bite force or occlusal contact area, regardless of the clenching level. Again, the exception to this observation was the second molar on the preferred chewing side, which had a larger area at the 30% clenching level. The results in normal subjects suggest that as the clenching intensity increases in the intercuspal position, the bite force adjusts to a position where it is well-balanced. This adjustment may prevent damage and overload to the teeth and temporomandibular joints.

Adult↗

PubMed1999

Dual-chamber pacing in hypertrophic obstructive cardiomyopathy: a comparison of acute and chronic effects.

This study describes the acute and chronic effects of dual-chamber (DDD) pacing in 14 consecutive patients with hypertrophic obstructive cardiomyopathy (HOCM), whose symptoms were refractory to drug therapy. Although left ventricular (LV) outflow tract pressure gradients diminished from 106+/-47 to 62+/-33 mm Hg (p<0.001) by temporary pacing, the residual pressure gradients were >30 mm Hg in the majority of those with concomitant reductions in cardiac output. The DDD pacing was judged as insufficient by the acute study in the majority of patients. A dual-chamber pacemaker was, however, implanted in 11 patients, and the chronic pacing effects were evaluated. All symptoms (syncope, fainting, palpitation and dyspnea) subsided within 1 month. Left ventricular outflow tract pressure gradients diminished from 99+/-56 to 21+/-13 mm Hg (p<0.004) at 1 week after, and to 17+/-12 mm Hg (p<0.002) at 1 year after the implantation, as measured by Doppler echocardiography. Echocardiogram showed disappearance of the systolic anterior motion of the mitral valve, and significant regression of the septal hypertrophy (from 18.5+/-4.3 to 15.7+/-4.1 mm, p<0.04). There was no significant correlation between the acute and chronic pacing effects in the reduction of the pressure gradients or symptomatic improvement. These results suggest that DDD pacemaker implantation is an effective treatment without any serious risks for patients with drug-refractory HOCM. The chronic-pacing effect in the reduction of the pressure gradient, the regression of hypertrophy and symptomatic improvement cannot be predicted by the assessment of temporary DDD pacing.

Adult↗

PubMed1999

Purification and characterization of phospholipase B from Kluyveromyces lactis, and cloning of phospholipase B gene.

Phospholipase B (PLB) from the yeast Kluyveromyces lactis was purified to homogeneity from culture medium. The enzyme was highly glycosylated with apparent molecular mass of 160-250 kDa, and had two pH optima, at pH 2.0 and pH 7.5. At acidic pH the enzyme hydrolyzed all phospholipid substrates tested here without metal ion. On the other hand, at alkaline pH the enzyme showed substrate specificity for phosphatidylcholine and lysophosphatidylcholine and required Ca2+, Fe3+, or Al3+ for the activity. The alkaline activity was increased more than 20-fold in the presence of Al3+ compared to that in the presence of Ca2+. cDNA sequence of PLB (KlPLB) was analyzed by a combination of several PCR procedures. KlPLB encoded a protein consist of 640 amino acids and the deduced amino acid sequence showed 66.7% similarity with the T. delbrueckii PLB. The amino acid sequence contained the lipase consensus sequence (G-X-S-X-G) and the catalytic aspartic acid motif. Replacement of Arg-112 or Asp-406 with alanine caused loss of the enzymatic activity at both pH. These results suggested that PLB activity are dependent on a catalytic mechanism similar to that of cytosolic phospholipase A2.

Acyltransferases↗

PubMed1999

The effect of cytokines on parathyroid hormone-related protein (PTH-rP) production in human amnion cells.

In the present study, the effects of various cytokines on parathyroid hormone-related protein (PTH-rP) production and PTH-rP mRNA expression in human amnion cells were studied. Immunoreactive (ir) PTH-rP was measured by immunoradiometric assay and the expression of PTH-rP mRNA was determined by Northern blot analysis. The addition of interleukin-1beta (IL-1beta, 10 ng/ml) and IL-6 (10 ng/ml) in culture medium for 24 hours resulted in a significant increase in ir-PTH-rP levels by 1.5 and 1.6 fold, respectively. The effects of these agents were dose dependent. In contrast, IL-2 (10 ng/ml) and IL-8 (10 ng/ml) showed no effect on the production of ir-PTH-rP from amnion cells. Treatment with IL-1beta or IL-6 for 6 hours increased the expression of PTH-rP mRNA in amnion cells. The stimulatory effect of IL-1beta was reduced by IL-1 receptor antagonist (IL-1Ra) in a dose dependent manner. Both tetradecanoyl phorbol acetate (TPA), and forskolin increased PTH-rP mRNA levels and the PTH-rP production in amnion cells, and the effect of TPA was much greater than that of forskolin. The findings of the present study suggest of the participation of inflammatory cytokines for the regulation of PTH-rP production in human amnion cells.

Amnion↗

PubMed1999

Attenuation of urinary sodium excretion during cold-air exposure in trained athletes.

To clarify whether an increase in urinary sodium (Na) excretion during cold-air exposure is attenuated in trained athletes, we analyzed the urinary and hormonal responses to cold-air exposure at 15 degrees C in trained (TR, n = 9) and untrained men (UT, n = 9). During 15 degrees C exposure in the UT group, the urinary Na excretion (UNaV), fractional excretion of Na and urinary Na to K ratio (UNa/K) increased significantly (p<0.01-0.05), but there were no variations in creatinine clearance or the filtered Na load. In the TR group, however, no significant changes were demonstrated in these parameters. The amount of increase in plasma noradrenaline and of decrease in plasma volume were greater, and the ADH and adrenaline responses were smaller in the TR group than those found in the UT group during 15 degrees C air exposure. A significant positive correlation was demonstrated between the increase of UNaV and both the relative changes of UNa/K and mean blood pressure. These results indicated that natriuresis during cold-air exposure was induced by the decrease in tubular reabsorption of Na, and that natriuresis was attenuated in trained athletes.

Adaptation, Biological↗

PubMed1999

[Rapid remission of pulmonary eosinophilic granuloma in a young male patient after cessation of smoking].

A 24-year-old asymptomatic man was referred to our hospital in October 7, 1997 for further examination of abnormal shadows detected on chest X-ray films that had been obtained during an annual health examination on September 12, 1997. The patient had suffered productive cough since the end of August 1997. A chest X-ray film obtained one year earlier showed no abnormalities. The patient had smoked 20 cigarettes per day since the age of 14. The findings of a physical examination and laboratory tests were unremarkable. A chest X-ray films showed micronodules 2-5 mm in size that were predominantly distributed in the upper and middle fields of both lungs. A chest computed tomogram (CT) showed multiple cysts measuring about 10 mm in diameter, with thick walls (2 to 3 mm) in addition to small nodular shadows. A transbronchial lung biopsy and a thoracoscopic lung biopsy revealed several stellate nodular fibrotic lesions containing some S-100 protein-positive, large mononuclear cells and lymphoid cells. An electron microscopic study found several Langerhans' cells with Birbeck's granules in their cytoplasm. A chest CT scan obtained 2 months after the patient stopped smoking (the day of admission) showed marked regression of the cystic shadows. Evidence suggests the pathogenesis of the disease is closely linked to smoking, and some case reports have documented clinical and radiographic improvements after patients stop smoking. Pulmonary small nodular lesions and cystic lesions with thick walls tend to undergo regression. Although surgical lung biopsy specimens disclosed several stellate nodular fibrotic lesions of eosinophilic granuloma that seemed to be histologically irreversible, our patient experienced remarkable regression of his pulmonary lesions within 2 months after the cessation of smoking.

Adult↗

PubMed1999

Cervical myelopathy due to dynamic compression by the laminectomy membrane: dynamic MR imaging study.

Dynamic magnetic resonance (MR) imaging is useful in assessing delayed neurologic deterioration after multilevel cervical laminectomy. The authors report a case of a 75-year-old woman who deteriorated 24 years after a C4-C7 laminectomy. When the extension MR demonstrated marked spinal cord compression attributable to a laminectomy membrane, the patient had an anterior diskectomy and fusion performed, after which she demonstrated significant neurologic improvement. In this and other cases, the dynamic MR may be a useful tool in discerning the etiology of the delayed neurologic changes occurring in postoperative patients.

Aged↗

PubMed1999

[Recurrence of hepatocellular carcinoma after liver resection].

Recurrence of hepatocellular carcinoma after liver resection is usually observed in the remnant liver, and includes metachronous multicentric occurrence and intrahepatic metastasis. In stage I and II, disease-free survival rates of clinical stage I patients are significantly better than those of clinical stage II patients, although there are no differences in the disease-free survival rates of patients with advanced disease. Disease-free survival rates in long-term survivors decreased at a constant rate due to metachronous multicentric recurrence. Therefore it is important to follow postoperative patients as long as possible. In the treatment of recurrent tumors, every effort should be made to resect the tumor in the liver. Then, other regional therapies, such as percutaneous ethanol injection therapy, microwave coagulation therapy, and transcatheter arterial chemoembolization, are indicated for patients for whom re-resection is not indicated. To prevent recurrence of hepatocellular carcinoma, it is also important to suppress the hepatic necroinflammatory process due to viral hepatitis.

Carcinoma, Hepatocellular↗

PubMed1999

[Usefulness of low dose 5'-DFUR (5'-deoxy-5-fluorouridine) for advanced or recurrent breast cancer].

The usefulness of low dose (600 mg/day) 5'-DFUR for advanced or recurrent breast cancer was evaluated. Eight patients out of 38 showed a partial response (response rate 21.1%), 22 patients had no change, and 8 patients had progressive disease. The response rate was 31.0% in soft tissue and 9.1% in bone, both of which were slight. In both one-shot (200 mg) and continuous (1-4 months) administration of 5'-DFUR (600 mg/day), the concentration of 5'-DFUR of 5-FU in sera reached a plateau from 30 minutes to 2 hours after administration of 5'-DFUR, and disappeared after 3 hours. There were no significant differences in the concentration of 5'-DFUR of 5-FU in sera between one-shot and continuous administration. It is concluded that there was no accumulation of the drug after continuous administration of 5'-DFUR, and that low dose 5'-DFUR is a useful therapy for advanced or recurrent breast cancer.

Administration, Oral↗

PubMed1999

[Usefulness and problems of total hepatic vascular exclusion in liver surgery].

Total hepatic vascular exclusion (THVE) is an useful method enabling safe and sure hepatic resection in patients with liver tumors adjacent to the large hepatic veins or inferior vena cava (IVC), tumor thrombi, invasion of the IVC, etc. To avoid serious hypotension during THVE, test clamping of the IVC prior to the procedure is indispensable. Hemodynamics should be carefully maintained by blood transfusion and sufficient infusion of colloidal and electrolyte solutions during THVE. The veno-venous bypass method which shunts blood from the IVC and portal vein to the superior vena cava enables prolongation of the period of THVE and is useful to avoid postoperative renal dysfunction. In situ liver perfusion with cold solution during THVE is an additional modality by which the liver is protected from warm ischemic injury and the duration of THVE can be further prolonged. However, the maximum duration of THVE is still controversial, especially in patients with chronic liver damage. The most appropriate method for THVE should be carefully chosen in each case by considering the type of lesion, liver function, and the goal of the surgery.

Constriction↗

PubMed1999

[Efficacy of mupirocin in eradicating methicillin-resistant Staphylococcus aureus from nasal discharge in carrying cardiovascular surgical patients].

Methicillin-resistant Staphylococcus aureus from nasal discharge was identified in 37 (2.5%) cardiovascular patients operated between 1995 and 1997; 25 male and 12 female, ranging from 1 to 83 years (mean 63); 2 were excluded because of Arbekacin or Isodine-gel treatment. The first 17 were treated with Vancomycin inhalation (V group) and eradication was considered to have been achieved when 3 consecutive negative cultures were obtained; the subsequent 18 were treated with Mupirocin (M group) and eradication was determined by 1 negative culture. In post-eradication electively operated 13 V and 15 M, postoperative MRSA infection was observed in one M (wound infection); the interval from the first nasal culture to the operation was 68 +/- 58 in V and 32 +/- 12 days in M, respectively (p < 0.05). In the remaining 7 who had to undergo emergency surgery while waiting for eradication because of progression of symptoms (2 V) or prior to instituting treatment (2 V, and 3 M), postoperative MRSA infection was observed in 2 M (both pneumonia). No deaths from infection were observed. Though the time required for conversion of the nasal culture was longer in V (13 +/- 20) than in M (7 +/- 1 days) differences were not significant. Mupirocin is easier to use, eradication can be achieved generally within a week.

Administration, Intranasal↗

PubMed1999

[A case of multiple bone metastases from advanced breast cancer effectively treated with pamidronate].

A 57-year-old woman, with bone, lymph node and skin metastases underwent mastectomy and extirpation of skin tumors. Chemoenderine-therapy was performed from the 15th day after operation, with a toremifene and CEF regimen consisting of cyclophosphamide, epirubicin and 5-fluorouracil. She had nausea and neurological symptoms from hypercalcemia (21.5 mg/dl) on the 28th day after operation. Her serum PTHrP level was found to be high at 214 pmol/l. We administered pamidronate in a dose of 45 mg biweekly, and she improved. The CEF regimen and pamidronate therapy was continued for 6 cycles and the regions of bone metastases were reduced on the bone scintography. Thereafter she has been administered pamidronate 30 mg/4 weeks as an outpatient with no further symptoms, and serum Ca and PTHrP have remained normal. In conclusion, pamidronate combined with chemotherapy can be a therapeutic option for not only hypercalcemia but also bone metastases of breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

[Evaluation of intermittent hepatic arterial infusion chemotherapy for multiple liver metastasis of colorectal cancer].

Five patients with synchronous multiple hepatic metastasis of colorectal cancer were treated with hepatic arterial infusion chemotherapy. All cases received intermittent 5-FU infusion (5-FU 250-1,000 mg/2-3 hrs/1-2 weeks) on an outpatient basis. In the evaluation of 5 cases, 3 PR and 1 NC were observed. One case administered arterial infusion for adjuvant chemotherapy has no recurrence in liver. In two patients, extra-hepatic metastases were found. In conclusion, this therapy was effective and useful for hepatic metastasis. Moreover, other forms of treatment for extra-hepatic metastasis must be used.

Adult↗

PubMed1999

[Intraperitoneal cisplatinum chemotherapy in patients with carcinomatous peritonitis due to colorectal scirrhous cancer--case report].

Two patients received intraperitoneal cisplatinum chemotherapy for carcinomatous ascites due to colorectal cancer recurrence. The patients were a 47-year-old man who had rectal cancer and 51-year-old woman who had colon cancer. They had received the operation and adjuvant chemoradiation therapy and chemotherapy respectively. However, five months and two years after resection, respectively, they presented massive ascites due to carcinomatous peritonitis and were given cisplatin injection intraperitoneally. The amount of ascites was significantly diminished. One patient had been discharged and been able to stay at home, and the other patient underwent gastrostomy for ileus. The results suggested that intraperitoneal cisplatinum chemotherapy may be useful for the patient with carcinomatous ascites due to colorectal cancer.

Adenocarcinoma, Scirrhous↗

PubMed1999

[Palliative chemo-radiotherapy for abdominal recurrence of esophageal carcinoma--case report].

A 71-year-old man with stage IV esophageal carcinoma was treated by chemo-radiotherapy (5-FU 500 mg/day + CDDP 10 mg/day for 4 weeks and 67.6 Gy of RT). The esophageal tumor showed a complete response to the treatment. Six months later, he had obstructive jaundice due to an abdominal recurrent mass. A secondary (palliative) CRT was performed (5-FU 500 mg/day + CDDP 10 mg/day for 3 weeks and 45 Gy of RT). The abdominal tumor became remarkably smaller and jaundice disappeared. Though the patient died from pulmonary carcinomatous lymphangitis, the primary lesion showed CR. CRT was very effective for local treatment and for palliative therapy.

Aged↗

PubMed1999

[Surgical treatment of septicemia after pacemaker implantation: a case report of removal of infected lead under median sternotomy].

A 73-year-old woman was admitted to our hospital because of septicemia associated with infection of an old retained pacemaker lead and a reimplanted pacemaker system. After general condition was recovered, the pacemaker system was removed and then the retained pacemaker lead was removed through median sternotomy. Then a new pacemaker system was implanted using myocardial leads. The postoperative course was uneventful.

Aged↗