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Biomedical subjects

M Kato

Publications and source records attributed to M Kato.

At least 559 records · Page 31Linked to original sources

The effects of morphine-induced increases in extracellular acetylcholine levels in the rostral ventrolateral medulla of rat.

The present study examined the role of the rostral ventrolateral medulla (RVLM) in the modulation of acetylcholine (ACh) release by morphine. We examined the effect of morphine on the release of ACh in the RVLM of freely moving rats using the in vivo microdialysis method. The basal level of ACh was 303.0 +/- 28.2 fmol/20 microliter/15 min in the presence of neostigmine (10 microM). Morphine at a low dose of 5 mg/kg (i.p.) increased ACh release by the RVLM by 42.4%. A higher morphine dose (10 mg/kg i.p.) significantly increased the release of ACh by 75.4%, with a maximal effect (86.4%) at 75 min. This enhancement following i.p. administration of morphine was reversed by naloxone (1 mg/kg i.p.). Addition of morphine (10(-4) M) to the perfusion medium increased the ACh release by 85.8% of the predrug values. The increased ACh release induced by local application of morphine was reversed by pretreatment with naloxone (1 mg/kg i.p.). The antinociceptive effect of locally applied morphine into the RVLM was assessed using the hot-plate test and tail immersion test in unanesthetized rats. Local application of morphine (10(-4) M) via a microdialysis probe induced an increase in both tail withdrawal and hot-plate response. These findings suggest that morphine seems to exert a direct stimulatory effect on ACh release by the RVLM and that morphine-induced nociception is, in part, activated by the release of ACh in freely moving rats.

Acetylcholine↗

QRST integral analysis of body surface electrocardiographic mapping for assessing exercise-induced changes in the spatial distribution of local repolarization properties in patients with coronary artery disease and in patients with previous anterior infarction.

We studied resting, postexercise, difference (postexercise - rest) QRST isointegral maps, and the correlation coefficient between resting and postexercise maps. Study I Fifteen controls and 48 patients without previous myocardial infarction were studied. In coronary syndrome X group (n = 14), no patients showed an abnormally negative area on the postexercise map. In coronary ST depression group (n = 26), 12 patients (46%) showed an abnormally negative area on the postexercise map, and the correlation coefficient was low. Although all control, syndrome X, and coronary ST depression patients showed the global-downward type of difference map, coronary ST elevation patients (n = 8) showed the right-downward and left-upward type, right-upward and left-downward type, or reversed saddle type. Coronary ST depression is related to a globally marked decrease in local repolarization forces. Coronary ST elevation is associated with multidirectional changes in local repolarization forces. Study II Fifty-one patients with previous anterior infarction (29 with residual ischemia and 22 without) were studied. The incidence of the global-positive type of maps was increased and that of the saddle-type map was decreased from rest to postexercise in both groups. The global-upward type or right-downward and left-upward type of difference map was observed in both groups, but the reversed saddle type, right-upward and left-downward type, or global-downward type was observed in the residual ischemia group (34%, 24%, and 14%, respectively). Residual ischemia causes multidirectional changes or a global decrease in local repolarization forces. In both studies, multidirectional changes in local repolarization forces may be related to the vulnerability to ventricular arrhythmias.

Adult↗

[Anesthesia experience of three patients with partial intramural coronary artery].

We experienced three patients with partial intramural coronary artery diagnosed preoperatively. We gave balanced anesthesia using narcotics and non-narcotic analgesics for non-cardiac surgery, administering phenylephrine against hypotension. The anesthetic course was relatively stable. According to the special pathophysiology of this disease, tachycardia and hypotension associated with anesthesia should be avoided, and special caution is needed when nitroglycerine is used due to its adverse effect on systolic narrowing of the coronary artery.

Aged↗

Efficient extraction by the liver governs overall elimination of hepatocyte growth factor in rats.

A steady-state pharmacokinetic analysis was performed to investigate the overall elimination and extraction of hepatocyte growth factor (HGF) by its target organs, including liver, kidney, and lung, during its constant i.v. infusion in rats. The plasma clearance of HGF became saturated as the steady-state plasma concentration (Cpss) increased, but complete saturation was not achieved, even when the Cpss ( approximately 1000 pM) was much higher than the dissociation constant for the HGF receptor (20-40 pM), which has been identified as one of the major clearance sites for HGF. This result suggests that there is a low-affinity and high-capacity clearance mechanism, other than receptor-mediated endocytosis, involved in its elimination from the body. The hepatic extraction ratio of HGF, assessed by determining the HGF concentration in both the circulating blood and hepatic vein, was 40 to 60%, whereas the HGF extraction both in kidney and lung was always less than 10%. Hepatic clearance accounted for approximately 70% of the plasma clearance at any Cpss. Thus, the present study shows that HGF in circulating plasma is efficiently extracted by the liver compared with other HGF target organs, the liver being involved in 70% of the overall elimination both under linear and nonlinear conditions. Biliary excretion of HGF was observed, but this accounted for only 0.1 to 0. 2% of the infusion rate, indicating that the nonlysosomal pathway of HGF, which avoids the lysosomal enzymes and transcytoses HGF directly into the bile, is very minor indeed.

Animals↗

[An autopsy case with lower motor neuron disease showing a transient-appearance of anti-GM1 antibody and an improvement of conduction block after gamma-globulin administration].

We report a 63-year-old man who died of respiratory failure. He was well until 1992 (57 years of his age), when he had an onset of progressive weakness of the bilateral upper limbs. He showed no improvement with TRH administration in other hospital. On January 12, 1994, he admitted to our department because of the progressive muscle weakness. Neurologic examination revealed a muscular atrophy associated with severe weakness and hyporeflexia in both upper limbs, and fasciculation were seen in his tongue. Electrophysiological studies revealed mild conduction block in the left medial nerve, and F-waves were not evoked in the left ulnar nerve and bilateral median nerves. After an administration of 25 g/day of human gamma-immunoglobulin for 5 days, conduction block as well as F-wave abnormalities in the left median and left ulnar nerve were improved, yet no improvement of muscle weakness was seen. The anti-GM1 IgG titer was transiently elevated in the patient's serum after gamma-immunoglobulin therapy. On September 8, 1994, subtotal gastrectomy was performed because of the early stage gastric cancer. Histological examination showed poorly differentiated adenocarcinoma (signet-ring cell carcinoma). His muscle weakness had been gradually extended to the lower limbs and he couldn't walk himself on January, 1998. On March, 1998, he developed tetraplegia, mild dysphagia, dysuria and the respiratory disturbance. On April 12, 1998, he admitted to our department for the second time. Neurologic examination revealed a muscular atrophy and fasciculation associated with severe weakness in all of his limbs, tongue and musclus masseter. Neither deep tendon reflex nor pathologic reflex was evoked in his upper and lower extremities. His ocular movements and sensations were well preserved. He died of respiratory failure on May 1, 1998. The patient was presented in a neurological CPC. Neurological and laboratory findings suggested a spinal progressive muscular atrophy (SPMA). However, there were several unusual points as a typical SPMA in this case, that is, an improvement of the electrophysiological abnormalities by gamma-globulin treatment, as well as transient elevation of anti-GM1 antibody. The clinical neurologists have arrived at the conclusion that the patient had lower motor neuron syndrome associated with anti-ganglioside antibody and cause of death was ascribed to the respiratory failure. We discussed whether this case was SPMA or multifocal motor neuropathy. Postmortem examination revealed numerous diverticulums in the ascending colon and lymphothyroiditis. No recurrent carcinoma was detected. Neuropathologically, both severe atrophy of the anterior spinal roots, and severe gliosis and neuronal loss in the anterior horn of the spinal cord were observed. Onuf nuclei were not affected. Neurogenic muscular atrophy was detected in the tongue, diaphragm, and limb muscles. Motor neurons of the brainstem were relatively preserved, but skein-like inclusions as detected by anti-ubiquitin antibody, were present in the facial and hypoglossal nuclei. Neither motor cortex nor cortico-spinal tracts were affected. Demyelination, remyelination or cellular infiltrations were not apparent in the right median nerve and sciatic nerves. The neuropathologic features were compatible with SPMA.

Autoantibodies↗

Recombinant light chain of human monoclonal antibody HB4C5 as a potentially useful lung cancer-targeting vehicle.

Recombinant lambda light chain of lung cancer-reacting human monoclonal antibody HB4C5 was expressed in Escherichia coli. Expression in bacteria ensured the generation of homogeneous light chain species devoid of activity-hampering N-linked glycosylation usually found in the light chain CDR-1 of HB4C5. Molecular engineering was also employed to eliminate the C-terminal two amino acid residues, i.e., Cys and Ser, to prevent the formation of lambda light chain dimers which are less reactive than the monomeric form. The lambda light chain was overexpressed in E. coli as inclusion bodies, which were solubilized, refolded, and treated with Aeromonas proteolytica aminopeptidase to remove the N-terminal Met with subsequent natural cyclization of the penultimate Gln residue to pyroglutamate, the same N-terminal end as that of naturally occurring lambda light chain in HB4C5. Monomeric recombinant lambda light chains, both before and after removal of the N-terminal Met residue, were 40 times more immunoreactive than the parent HB4C5. The immunostaining of lung cancer tissue sections with the recombinant lambda light chain indicated cancer-specific reactions to all specimens of adenocarcinoma, squamous cell carcinoma and large cell carcinoma histologies, but did not react with small cell carcinoma. Tumor radioimmunoimaging experiments in LC6 (lung squamous cell carcinoma line)--xenografted nude mice by the i.p. injection of 125I-labeled recombinant lambda light chain and 125I-labeled human lambda light chain control gave tumor-specific and recombinant lambda light chain-dependent images on day 5 postinjection, and images were also detectable on day 3. Biodistribution studies with 125I-labeled recombinant lambda light chain demonstrated that the lambda light chain could penetrate better into the tumor sites, both at the necrotic and solid parts of the xenograft, as compared to our previous results with 125I-labeled HB4C5 which could localize to the necrotic part only. These results suggest that the recombinant lambda light chain is potentially useful as a lung cancer-targeting vehicle, for such as radioimmunoimaging and radioimmunotherapy, with least possible adverse immunogenic effects.

Amino Acid Sequence↗

[Surgical treatment for distal aortic arch aneurysm using stent grafting].

To alleviate the invasiveness of surgical treatment for distal aortic aneurysm or dissection, we have been using a stented graft to replace the distal anastomotic suture of the descending aorta. We also developed a new stent graft implanting method for distal aortic aneurysm or dissection which uses cervical branch bypasses from the ascending aorta and requires no extracorporeal circulation. These new surgical treatments for distal arch aneurysm result in low surgical mortality (3.8%) and low surgical morbidity rates (stroke, 7.7%; respiratory complications, 7.7%; no renal complications). These results indicate that these new graft implanting methods using stent graft should be considered as a less-invasive surgical treatment for distal aortic aneurysm or dissection.

Aged↗

[Reduction in the window period of an acute infection by chemiluminescence enzyme immunoassay of HIV-1 p24 antigen].

To evaluate the detectability of HIV-1 p24 antigen in the window period of an acute infection, 172 HIV-1-infected and 78 HIV-1-uninfected adult serum (plasma) samples were assayed by chemiluminescence enzyme immunoassay (CLEIA, 2 step sandwich method) and EIA. All 78 HIV-uninfected samples (100%) were p24 antigen negative by both methods. Thirty five of the 172 HIV-1-infected samples (32.1%) were p24 antigen negative by EIA, and p24 antigen positive by CLEIA. The HIV-1 RNA levels of the 35 discrepant samples were 8.1 x 10(3)-7.9 x 10(5) copies/ml, TH/I lymphocyte levels of them were less than 200 cells/microliter except 9 cases, and phases of them were AIDSs of CDC 1993 classification except 7 cases. The antigen detection limit of CLEIA was 3.1-6.3 pg/ml, and that of EIA was 12.5-25.0 pg/ml. The coefficient of variations of CLEIA were 3.0-6.3% determined after the assay on 5 samples on 5 different days, 6 times per day. On the basis of these results, it was inferred that the reason for the discrepancy between the two methods was due to the fact that the detection limit of CLEIA was lower than that of EIA. On an antibody-negative RNA-positive (5.0 x 10(4) copies/ml) serum sample in the window period of an acute infection, p24 antigen was detected by CLEIA 7 days earlier than by EIA. CLEIA was judged to be a useful assay for reducing the window period, and a cost-effective (effect/cost > 1.0) method.

Adult↗

[Evaluation of left ventricular diastolic function during coronary artery bypass grafting by color M-mode Doppler echocardiography].

The objective of the present study was to evaluate the effects of the coronary artery bypass graft surgery (CABG) and cardioplegic arrest on left ventricular diastolic function. Ten patients with coronary artery disease were studied by transesophageal Doppler echocardiography. Doppler measurements included peak velocity during early filling (peak E velocity), peak velocity during atrial contraction (peak A velocity), and the ratio of peak E velocity to peak A velocity (E/A). The rate of propagation of peak early filling flow velocity (FPV) was also measured using color M-mode Doppler echocardiography. Hemodynamic and Doppler-derived variables were measured before and after sternotomy, after the end of cardiopulmonary bypass (CPB) and after closure of the sternum. E/A showed a significant decrease after sternotomy and did not return to the pre CPB level. FPV increased after CPB. FPV was correlated with E/A (r = 0.54, P = 0.013 pre-CPB; r = 0.54, P = 0.014 post-CPB). E/A showed a significant correlation with heart rate. After the influence of heart rate had been eliminated by the analysis of covariance, corrected E/A value showed a significant increase post-CPB compared to that in pre-CPB (0.68 +/- 0.29 to 1.10 +/- 0.29, P < 0.05). In conclusion, FPV and heart-rate-corrected E/A increased after CPB. This suggests improvement of diastolic function during CABG.

Aged↗

[Clinical evaluation of intermittent hepatic arterial infusion therapy with CDDP and 5-FU for liver metastasis of colorectal cancer].

Twenty-seven patients with liver metastasis from colorectal cancer were treated with intermittent intra-arterial infusion chemotherapy for 5 years starting from 1993. Five to ten mg of CDDP, 250 mg of 5-FU and/or 3-6 mg of Leucovorin were administered weekly. In the case of nonresponders, the dose of 5-FU was allowed to increase toward 500 mg. The above schedule was repeated as long as possible. The average number of administrations in 12 out of 27 unresectable patients was 28.7. The response rate was 50% (CR; 4 cases, PR; 2), with 2 NC and 3 PD. Four patients given 500 mg of 5-FU showed some response. The 50% survival period was 466 days, and the 1- and 3-year survival rates were 66.7% and 18.3%, respectively. The average number of administrations in the group of patients who underwent prophylactic treatment and resection of the metastasis was 33.1. During an average observational period 681 days, 7 patients (46.7%) had a recurrence in the liver. The 5-year survival rate was 85.7%. The patients who were treated with 250 mg 5-FU experienced no severe side effects, but one who was given 500 mg 5-FU developed a duodenal ulcer.

Adult↗

[Aseptic meningitis induced by high-dose gamma-globulin in an adult woman with antiphospholipid syndrome and chronic idiopathic thrombocytopenic purpura].

It is well known that the administration of high-dose gamma-globulin concentrate is effective in alleviating thrombocytopenia in patients with idiopathic thrombocytopenic purpura (ITP). However, treatment can sometimes induce aseptic meningitis. A 25-year-old Japanese woman with antiphospholipid syndrome and ITP was conditioned with high-dose gamma-globulin concentrate prior to splenectomy. Three days after the initial gamma-globulin course, she experienced severe headache, vomiting, and high-grade fever. Cerebrospinal fluid examination yielded a diagnosis of aseptic meningitis. The patient's clinical symptoms and abnormal cerebrospinal fluid findings disappeared immediately after the discontinuation of gamma-globulin therapy. Cases of aseptic meningitis induced by high-dose gamma-globulin therapy are uncommon in the literature, and most involve children. Moreover, to our knowledge, only 1 Japanese adult ITP case of gamma-globulin-induced aseptic meningitis has been reported to date. Aseptic meningitis may be one of the important adverse effects of the administration of high-dose gamma-globulin concentrate to pediatric as well as adult ITP patients.

Adult↗

Correspondence.

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Journal Article↗

[An autopsy case of MPO-ANCA-positive microscopic polyangiitis with manifestations of pulmonary hemorrhage and diffuse alveolar damage].

A 68-year-old woman was admitted to our hospital because of fever of unknown origin and pain in the lower extremities. Six weeks after onset, diffuse infiltrative shadows were observed on chest X-ray films, and marked hypoxemia and progressive renal dysfunction suddenly developed. Corticosteroid therapy (2 courses of pulse therapy, each consisting of methylprednisolone at 500 mg/day for 3 days) was not effective, and the patient died 9 weeks after onset because of respiratory failure. Serologic tests were positive for MPO-ANCA. Histopathologic findings at autopsy disclosed arteriolar fibrinoid necrosis in tissues of the liver, spleen, lungs, and kidneys, thus yielding a diagnosis of microscopic polyangiitis. Lung specimens also demonstrated massive alveolar hemorrhaging in the mid-lung fields and diffuse alveolar damage (DAD) in all lobes. Pulmonary hemorrhage coexistent with DAD worsens the prognosis for microscopic polyangiitis in patients positive for MPO-ANCA.

Aged↗

Eradication of Helicobacter pylori using 30 mg or 60 mg lansoprazole combined with amoxicillin and metronidazole: one and two weeks of a new triple therapy.

A new triple therapy using a proton pump inhibitor and two antibiotics shows high efficiency against Helicobacter pylori infection. The aim of this study was to determine the optimal dose and duration of lansoprazole (LA) administration in combination with amoxicillin (AMPC) and metronidazole (MNZ). A total of 91 patients were enrolled in this study. They were divided into four groups: group A, 2 weeks of 30mg LA once daily, 500mg AMPC tid, and 250mg MNZ tid; group B, 2 weeks of 30mg LA bid, 500mg AMPC tid, and 250mg MNZ tid; group C, 1 week of 30mg LA once daily, 500mg AMPC tid, and 250mg MNZ tid; group D, 1 week of 30mg LA bid, 500mg AMPC tid, and 250mg MNZ tid. H. pylori status was determined by the rapid urease test, culture, histology, and 13C-urea breath test before and at least 4 weeks after the end of therapy. The cure rates in a per-protocol analysis and the incidence of adverse events in the evaluated patients were, respectively, 89.5% and 21.1% in group A, 100% and 20.0% in group B, 96.8% and 12.9% in group C, and 92.3% and 26.9% in group D. Most of the adverse events were tolerated. All four regimens in this study showed the same cure rates, and they were effective and well tolerated. One week of triple therapy using once-daily administration of 30mg LA is a good alternative.

2-Pyridinylmethylsulfinylbenzimidazoles↗