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Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 649 records · Page 36Linked to original sources

Recruitment of several neuroprotective pathways after permanent focal ischemia in mice.

After an ischemic episode induced by the electrocoagulation of the left middle cerebral artery (MCA) in mouse, neurons within the damaged territory die either by an apoptotic or by a necrotic process. Most of the cortical neurons within the ischemic area display both morphological and biochemical signs of programmed cell death: nuclear condensation, DNA degradation, formation of apoptotic bodies, and glutathione depletion. In fact, apoptosis essentially contributes to the expansion of the ischemic lesion and the maximum of damaged territory is reached 24 h postocclusion. Several potentially neuroprotective pathways have been evidenced in different experimental models of ischemia including the activation of antioxidant enzyme activities and/or the recruitment of neurotrophic as well as antiapoptotic factors. In our model of permanent focal ischemia induced by MCA occlusion, we measured the temporal synthesis of nerve growth factor (NGF) and examined the status of antioxidant enzymes as well as Bcl-2 antiapoptotic product. We detected in both cortices a transient increase of NGF which peaks at 6 h. Moreover, we reported that glutathione peroxidase is recruited with a time course which parallels NGF synthesis. Finally, we observed the induction of Bcl-2 in safe neurons; this may represent a self-protective response against ischemia-induced apoptosis. We provide evidence that in a model of permanent focal ischemia, several neuroprotective pathways could be coactivated.

Animals↗

Nonradioactive differential display cloning of genes induced by homocysteine in vascular endothelial cells.

Hyperhomocysteinemia is known to be a risk factor for arteriosclerosis and thrombosis. To elucidate the mechanisms by which homocysteine may promote vascular diseases, we have applied a modified nonradioactive differential display analysis that evaluates changes in gene expression induced by homocysteine treatment of cultured human umbilical vein endothelial cells (HUVECs). We identified six upregulated and one downregulated gene. One upregulated gene was GRP78/BiP, an endoplasmic reticulum (ER)-resident molecular chaperone, suggesting that unfolded proteins would accumulate in the ER because of redox potential changes caused by homocysteine. Another upregulated gene encoded a bifunctional enzyme with activities of methylenetetrahydrofolate dehydrogenase and methenyltetrahydrofolate cyclohydrolase, which is involved in homocysteine metabolism. A third upregulated gene encoded activating transcription factor 4. Homology searches of the remaining four clones failed to retrieve any similar sequences with a known function. We isolated a full-length cDNA of one of the upregulated genes from a HUVEC library. It encoded a novel protein with 394 amino acids, which was termed RTP (reducing agent and tunicamycin-responsive protein). Northern blot analysis revealed that RTP mRNA expression was induced in HUVECs treated with not only homocysteine but also 2-mercaptoethanol and tunicamycin, both of which are known to induce ER stress. RTP mRNA was ubiquitously expressed in human adult organs, and seemed to be regulated in mouse embryogenesis. Consequently, our differential display analysis revealed that homocysteine alters the expressivity of multiple proteins, especially ER stress-responsive ones. This potential ability of homocysteine may be involved in atherogenesis.

Amino Acid Sequence↗

Outcome of patients with early stage lung cancer.

A study was conducted to evaluate the outcomes of 79 patients with early stage lung cancer diagnosed according to the following criteria. Central tumors were located in the segmental bronchi, or more proximally, and tumor invasion was limited to the bronchial wall without lymph node or distant metastases. Peripheral tumors were located distal to the subsegmental bronchi and were less than 2 cm in greatest dimension, and invasion was limited to the visceral pleura, with no lymph node or distant metastases. The 5-year survival rate was 100% for patients with peripheral type early squamous cell carcinoma, 94.6% for those with central-type early squamous cell carcinoma, and 79.3% for those with early adenocarcinoma. The 5-year survival rate for patients with central-type squamous cell carcinoma without pericartilage layer invasion was 97.0%, and that for those with T1N0M0 peripheral squamous cell carcinoma was 100.0%. To define early stage lung cancer as curable, it should be defined as T1N0M0, peripheral squamous cell carcinoma, or central squamous cell carcinoma without pericartilage layer invasion. For other histologic types, some added parameters are needed. The rate of multiple lung cancers was 10.1% and that of multiple primary malignant disease was 13.9%. Thus, careful followup of patients with early stage lung cancer should be carried out, as second malignancies in the lung and elsewhere are commonly detected.

Adenocarcinoma↗

Influence of luteinizing hormone-releasing hormone analogues on serum levels of prostatic acid phosphatase and prostatic specific antigen in patients with metastatic carcinoma of the prostate.

Serum concentrations of luteinizing hormone (LH), testosterone, prostatic acid phosphatase (PAP) and prostatic specific antigen (PSA) were measured in 16 patients with advanced prostatic cancer before and after treatment with luteinizing hormone-releasing hormone (LHRH) analogue. An initial rise of serum LH and testosterone levels was observed on day 2 of the treatment. Subsequently, serum concentrations of PAP and PSA showed a transient increase on day 5 of the treatment. This indicates that LHRH analogues had better be given in combination with antiandrogens in patients with metastatic carcinoma of the prostate.

Acid Phosphatase↗

Ischemic stricture of the small intestine associated with acute pancreatitis.

A 37-yr-old man underwent an open drainage operation for severe acute pancreatitis and received respiratory ventilation support for 4 mo because of respiratory failure based on disseminated intravascular coagulation (DIC) and septic shock. Under intensive care, he sometimes had bloody diarrhea for about 6 wk. Colonoscopic findings suggested that the bleeding had derived from the small intestine. The patient then gradually recovered from acute pancreatitis and was discharged from the hospital. Thereafter, he suffered relapses of ileus and his symptoms progressively worsened. The patient underwent a second operation about 2 yr after the onset of acute pancreatitis. At celiotomy, multiple stenoses of the distal ileum measuring about 60 cm in length were found and the segment was resected. The resected specimen demonstrated six separate circumferential strictures and shallow ulcerations. Histologically, multiple ulcerations were restricted to the mucosa and were accompanied by marked submucosal edema and fibrosis. The mucosa between the ulcers revealed chronic regenerative changes: intimal thickening of small mesenteric arteries causing luminal narrowing and organized thrombosis in small mesenteric veins. Therefore, these were considered to be a series of segmental ischemic lesions. Note that delayed ischemic stricture of the small intestine may occur as a chronic complication of acute pancreatitis.

Acute Disease↗

[Evaluation of hilar pulmonary vessels using magnetic resonance angiography (MRA)].

To evaluate the usefulness of magnetic resonance angiography (MRA) in pulmonary and mediastinal diseases, 24 cases (15 lung cancers, 2 metastatic lung tumors and 7 other diseases) were studied with the 3D FLASH (TE = 3 msec.) method. In resected cases, MRA images were compared with intraoperative findings. Twenty of 24 cases were consistent with intraoperative findings. In 4 resected cases in which the findings were inconsistent, pulmonary angiography (PAG) findings were similar to those of MRA. From these results, MRA is considered an effective and non-invasive method for evaluation of pulmonary vessels.

Aged↗

[Intratumoral heterogeneity of DNA content in lung adenocarcinoma].

Quantitative microspectrophotometry was performed in 10 resected lung adenocarcinomas for the purpose of studying intratumoral heterogeneity of DNA content. Histologically, there were 3 stage I, 2 stage IIIA, 2 stage IIIB, and 3 stage IV cases, consisting of 3 well, 4 moderately and 3 poorly differentiated cases. The tumors were cut at the greatest dimension and fine needle aspirations were performed from 5 separate areas (central, cranial, caudal, inward, and outward). One of the imprint smears was submitted for cytology and the other for microspectrophotometry using Feulgen staining. Although G0G1 and G2M phase cell populations varied in each specimen, all 5 specimens showed the same DNA histogram in 9 cases. These were 4 aneuploid, 4 polyploid (euploid but not diploid) and only one diploid tumor. Two stem lines were observed in the remaining single case. One of 5 specimens showed aneuploid, the other 4 specimens showed polyploid. Namely, intratumoral heterogeneity was observed in one case. Ther was no relationship between intratumoral heterogeneity tumor size or differentiation. Most lung adenocarcinomas showed DNA stability. Fine needle aspiration specimens obtained from one area of lung adenocarcinoma represent the DNA contents of the entire tumor.

Adenocarcinoma↗

A rare case of spontaneous esophageal rupture (Boerhaave's syndrome) associated with pulmonary rupture.

Spontaneous esophageal rupture (Boerhaave's Syndrome) is a life-threatening condition that requires early diagnosis and effective treatment. The authors describe a rare case of spontaneous rupture of the esophagus associated with pulmonary rupture in a 54-year-old man. The anatomical basis for the occurrence of a spontaneous esophageal rupture associated with pulmonary rupture is discussed.

Esophageal Diseases↗

[Changes of serum cytokine levels after thoracoscopic esophagectomy].

We introduced thoracoscopic esophagectomy with extended lymphadenectomy for reduction of respiratory dysfunction and less surgical intervention in July 1995. In this study, we investigated the changes in serum interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) levels in 8 patients (TS Group) who underwent thoracoscopic esophagectomy with extended lymphadenectomy and compared them with the changes in patients who underwent conventional thoracotomy (CT Group). The duration of the operation and intrathoracic procedure in the TS group were significantly longer than in the CT group. However, the amount of blood loss and intrathoracic blood loss of the TS group were not significantly higher than in the CT group. The number of dissected lymph nodes was not significantly larger. The serum IL-6 levels reached maximum levels 3 hours from the end of operation. In the TS group, the changes in IL-6 levels were significantly larger (p < 0.05). On the other hand, the changes in CRP levels were also significantly larger (p < 0.01). Significant correlation was observed between the duration of the intrathoracic procedure and the maximum levels of IL-6. On the other hand, serum IL-1ra levels were not significantly. At present, these results suggest that the surgical intervention of thoracoscopic esophagectomy are more larger than that of conventional thoracotomy. We think that the length of intrathoracic procedure of thoracoscopic esophagectomy may make more large surgical stress.

Endoscopy↗

Lobectomy: video-assisted thoracic surgery versus posterolateral thoracotomy.

BACKGROUND: Video-assisted lobectomy has been adopted by many thoracic surgeons, because it is a less invasive approach to small peripheral lung cancers. However, some authors disagree that video-assisted lobectomy is less invasive than traditional thoracotomy and lobectomy. The purpose of this study was to evaluate the advantages of video-assisted lobectomy over posterolateral thoracotomy and lobectomy in terms of pain-related morbidity. METHODS: A total of 70 patients with clinical T1N0M0 non-small-cell lung carcinomas underwent lobectomy with complete mediastinal lymphadenectomy. Of these 35 underwent posterolateral thoracotomy (between April 1994 and December 1995; open group), and 35 underwent video-assisted thoracic surgery (VATS) (between January and December 1996; VATS group). RESULTS: Although the operative time was significantly longer in the VATS group (p = 0.04), the intraoperative blood loss was significantly less (p = 0.03). No significant differences were found for the two groups with respect to the total number of mediastinal lymph nodes dissected or duration of chest tube drainage. Postoperative pain was less severe as determined by the number of doses of analgesics required between postoperative days 0 and 7 (p < 0.0001), and the length of postoperative hospitalization was shorter in the VATS group (p < 0.0001). CONCLUSION: Video-assisted lobectomy is associated with decreased postoperative pain and shortened length of postoperative hospitalization, when compared with posterolateral thoracotomy and lobectomy.

Adult↗

[Blunt thoracic injury].

Of 161 patients with blunt thoracic injury, 135 were male (83.9%) and 26 were female. The most common cause of injury was traffic accidents (130 patients, 80.7%), followed by falls (22 patients), and crushing (7 patients). There were 46 third decade and 36 second decade patients. Thirty-two patients had single thoracic injury and the other had multiple organ injury. The most common associated injury was head injury (65 patients). Most traffic accidents involved motor cycle accident. Forty-four patients died, 32 within 24 hours, and 4 died to thoracic injury. These 4 patients were shock on arrival and died within 24 hours. The injury severity score, which was under 30 in 78.3% of patients, correlated to the mortality rate. Rib fracture was the most common thoracic injury in 96 patients followed by hemothorax in 91, pulmonary contusion in 79, and pneumothorax in 64. Most of the thoracic injuries were treated conservatively. Thoracotomy was performed in 6 patients. Other than one patient with rupture of the left pulmonary vein, 5 patients recovered. Continued bleeding at a rate of more than 200 ml/h from the chest drainage tube or no recovery from shock and large air leakage preventing re-expansion of the lung are indications for emergency thoracotomy. Thoracotomy should also be considered after conservative treatment in patients with continued air leakage or intrabronchial bleeding negatively affecting respiration. Indications for thoracotomy should be determined individually based on evaluating of vital sign.

Accidents, Traffic↗

Effect of the mono- and tetra-sialogangliosides, GM1 and GQ1b, on long-term potentiation in the CA1 hippocampal neurons of the guinea pig.

Effects of the mono- and tetra-sialogangliosides, GM1 and GQ1b, on long-term potentiation (LTP) were investigated in the CA1 neurons of guinea-pig hippocampal slices. The magnitude of LTP induced by a strong tetanus (100 Hz, 100 pulses) was not significantly affected by application of either ganglioside. In contrast, when LTP was induced by a weak tetanus (100 Hz, 4 pulses), a significantly greater LTP was induced in the presence of either ganglioside. Similarly, when slices were incubated in low-Ca2+ (1.0-1.1 mM) medium for more than 2 h, the LTP was usually small or absent, but showed a significant increase in amplitude of population spike (A-PS) when the slices were incubated with either GM1 or GQ1b (4-5 microg/ml). In addition, the application of GQ1b (4 microg/ml) reversed the blocking effect of an NMDA-receptor antagonist, APP-5 (10 microM), on the induction of LTP and resulted in forming LTP. Based on these findings, we conclude that GM1 and GQ1b exert positive modulatory effects on the induction of LTP in hippocampal CA1 neurons and suggest that GM1 and GQ1b may participate in the induction of LTP as donors of Ca2+ ions.

Animals↗

Diagnosis of the first Japanese patient with 3-oxo-delta4-steroid 5beta-reductase deficiency by use of immunoblot analysis.

UNLABELLED: A 3-oxo-delta4-steroid 5beta-reductase (5beta-reductase) deficiency is difficult to diagnose because severe liver damage can result in a similar pattern of metabolite excretion. We investigated the usefulness of immunoblot analysis for diagnosis of 5beta-reductase deficiency and quantitatively analysed urinary bile acids by gas chromatography-mass spectrometry in a 5-month-old Japanese boy with severe neonatal cholestasis associated with hypertyrosinaemia. A liver sample was examined by immunoblot analysis using monoclonal antibodies against 5beta-reductase. Urinary 3-oxo-delta4 bile acids accounted for 88.3% of total bile acids, 5alpha-bile acids for 0.9%, and primary bile acids for 9.1%. Immunoblot analysis of the liver tissue showed an indistinct band of 5beta-reductase. CONCLUSIONS: These findings suggest that this patient had a secondary 5beta-reductase deficiency due to severe liver damage, even though 3-oxo-delta4 bile acids constituted more than 70% of total urinary bile acids. However, the patient may possibly have had an inherited 5beta-reductase deficiency.

Amino Acid Metabolism, Inborn Errors↗

Age-related changes in the cerebrospinal fluid level of beta-endorphin and substance P. Short communication.

To evaluate the early age-related changes in neuropeptides, we have measured the cerebrospinal fluid (CSF) levels of beta-endorphin and substance P in young patients over a range of ages. Specimens of CSF were obtained from 39 neurologically normal children, aged 1 month to 10 years of age, and in 9 adult controls. CSF levels of both neuropeptides were observed to peak during the first year of life, and showed a negative correlation with increasing age. A significant positive correlation was observed between the CSF level of beta-endorphin and that of substance P.

Adult↗

Nucleotide sequence of the gene encoding the RNA polymerase and the 3' non-coding region of a bovine enterovirus Japanese isolate: rapid synonymous substitutions between European and Japanese strains.

The nucleotide sequences of the genome RNA encoding the RNA polymerase and the 3' non-coding region (NCR) of bovine enterovirus (BEV) serotype I Japanese isolate, MZ468, were determined. The genetic distance between the two BEV serotype I strains, MZ468 and VG-5-27, was calculated by pairwise comparison of nucleotide sequences. The synonymous substitution rate was high (1.40 x 10(-2)/site/year), and of the same order as those of influenza virus HA, HIV-1 gag and env, and enterovirus 70 VP1 genes.

Amino Acid Sequence↗