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Biomedical subjects

K Katoh

Publications and source records attributed to K Katoh.

At least 163 records · Page 9Linked to original sources
PubMed1993

Coding of odor molecules by mitral/tufted cells in rabbit olfactory bulb. II. Aromatic compounds.

1. Recordings of extracellular spike responses were made from single mitral/tufted cells in the ventromedial region of the main olfactory bulb of urethan-chloralose-anesthetized rabbits. Using periodic artificial inhalations, the olfactory epithelium was stimulated with series of aromatic and aliphatic compounds systematically varying in molecular conformation. 2. Analysis of response specificity of single mitral/tufted cells for alkylbenzenes indicated that the length of the hydrocarbon side chain attached to the benzene ring plays a role in determining the specificity of excitatory spike responses. 3. For a panel of isomeric (ortho-, meta-, and para-positions) disubstituted benzenes, single mitral/tufted cells tended to be activated selectively by one or two specific structural isomer(s). For a panel that contained both alkylbenzenes and disubstituted benzenes, single mitral/tufted cells were activated by subsets of odor molecules having similar conformations. These observations suggest that the overall conformation of the aromatic compounds plays an important role in determining tuning specificity of individual mitral/tufted cells. 4. For a panel of monosubstituted benzenes with various functional groups, single mitral/tufted cells in the ventromedial region tended to be activated not only by molecules having a hydrocarbon side chain (alkylbenzenes), but also by those having a methoxy group (--O--CH3), a bromine (--Br), or a chlorine (--Cl). However, most of the neurons were not activated by those having an amino group (--NH2), a hydroxy group (--OH), nor a carboxyl group (--COOH). 5. Examination with an expanded panel of stimulus odor molecules that included both aromatic and aliphatic compounds indicated that single mitral/tufted cells show excitatory spike responses to a range of odor molecules (molecular receptive range) having similar conformations. Different mitral/tufted cells in the ventromedial region typically showed different molecular receptive ranges. 6. In mitral/tufted cells with relatively high spontaneous discharges, single neurons in the ventromedial region showed inhibitory responses to subsets of odor molecules in addition to the excitatory response to other subsets of odor molecules. The odor molecules that caused inhibitory responses in single mitral/tufted cells showed molecular conformations resembling each other. 7. The present results together with previous studies indicate that determination of the molecular receptive range properties (both excitatory extent and inhibitory extent) of single mitral/tufted cells is a useful method for characterizing individual bulbar neurons. These results further support the hypothesis that conformational parameters of ligand odor molecules play a key role in sensory processing in the main olfactory bulb.

Animals↗
PubMed1993

[Adenocarcinoma of colon 19 years after ureterosigmoidostomy: a case report].

A 65-year-old man underwent total cystectomy in 1972 for a bladder tumor. Ureterosigmoidostomy was performed in this case. A physical examination in 1983 revealed occult blood in the feces, and colon fiberscopic examination disclosed a polyp in this patient, who then underwent polypectomy. Histology confirmed hyperplasia. In 1985, colon fiberscopic examination revealed a polyp in the sigmoid, resulting in another polypectomy. Adenoma was established by histology. In April 1991, fresh blood was found in the feces, and a Borrmann II tumor was confirmed by colon fibrerscopic examination. Sigmoidectomy, colostomy, and right ureterostomy were performed. Histology confirmed moderately differentiated adenocarcinoma.

Adenocarcinoma↗
PubMed1993

[Study on odor control using wood vinegars].

The effectiveness of wood vinegars reducing or eliminating offensive odors, associated with cattle breeding, was studied. The results obtained were as follows: 1. Analyzed were 0.7-7.2% acetic acid and 0.5-1.8% methyl alcohol as main contents. 2. Gaseous odorants, such as ammonia, trimethylamine, n-butyric acid were almost eliminated through absorption using 1-20% wood vinegar solutions. 3. The same gaseous odorants, mentioned above, when confined to an airtight vessel, were eliminated in a short time by adding a little volume of wood vinegars to it. The effect was maintained for 2 weeks. 4. A sensory test was performed to evaluate the degree of deodorization, such as odor intensity and odor acceptability. Results showed that wood vinegars have a good deodorant effect on the offensive odors.

Acetates↗
PubMed1992

Axonal flow blockade induces alpha-CGRP mRNA expression in rat motoneurons.

Axonal flow of motoneurons was blocked in the sciatic nerve by the application of vinblastine at a low concentration (100 microM) not considered likely to cause axonal degeneration. The number of motoneurons expressing alpha-calcitonin gene-related peptide (CGRP) mRNA was significantly increased by vinblastine application, while the expression of beta-CGRP mRNA was not influenced. These findings suggest that the synthesis of these two peptides is differentially regulated and that alpha-CGRP mRNA is possibly down-regulated by unknown factor(s) which normally undergo retrograde transport from the periphery.

Animals↗
PubMed1992

[MR angiography of the lung using 3-dimensional imaging method].

Three-Dimensional MR angiography (3D-MRA) of the lung was performed in 5 healthy volunteers and 14 patients with primary pulmonary cancer in the hilum, and compared with 2D-MRA. As 3D-MRA could be obtained with single breath holding after intravenous bolus injection of Gd-DTPA, pulmonary vessels of the hilum and peripheral zone were demonstrated more definitely than those of 2D-MRA. In all patients except one case, the relation between the tumor and pulmonary vessels was visualized more clearly by 3D-MRA than 2D-MRA. This technique is considered a non-invasive and effective method for evaluation of pulmonary vessels in the patient with hilar tumor.

Humans↗
PubMed1992

Antianginal effects of amlodipine at a single dose on exertional angina patients using treadmill exercise testing--a randomized crossover study in comparison with placebo.

With eight cases of stable exertional angina as subjects, the antianginal action and sustained effects of single 10 mg oral doses of new calcium antagonists amlodipine were assessed by treadmill exercise tests in randomized crossover trials with respect to a placebo. Exercise tests were conducted before as well as 4, 8, and 24 hours after administration, and plasma amlodipine concentration was investigated at the same times. The maximal exercise time was 299 +/- 43 seconds before as compared with 346 +/- 49 seconds 4 hours after administration and 368 +/- 50 seconds 8 hours after administration, a significant prolongation in each case (p < 0.01). Moreover, the exercise time elapsed until 1 mm of ST-segment depression, as well as the ST-segment depression measured at the same time, were both significantly improved as compared with the placebo results. The plasma amlodipine concentration reached a peak 8 hours after administration and displayed an effective level even 24 hours after administration. The value of delta PRP measured at the same time during the exercise test was also significantly reduced as compared with the placebo results, even 24 hours after administration of amlodipine. These findings supported the conclusion that single 10-mg doses of amlodipine provide stable antianginal action over a 24-hour period.

Administration, Oral↗
PubMed1992

Relationship between superoxide dismutase (SOD) and viral liver diseases.

Immunohistochemical evaluation of Cu, Zn- and Mn-superoxide dismutase (SOD) activity in various viral liver diseases was performed by the peroxidase-conjugated antibody indirect method. Anti-human Cu, Zn-SOD (rabbit) and anti-human Mn-SOD (guinea-pig) derived and purified from SOD of human erythrocytes and placentas were used to determine SOD distribution in liver tissues. SOD in the liver tissues was detected in 68 inpatients of our unit. They consisted of 23 cases with chronic hepatitis caused by hepatitis B virus (13) and hepatitis C virus (10), 24 with liver cirrhosis caused by hepatitis B virus (5) and hepatitis C virus (19) (15: compensatory, 9: decompensatory) and 21 with hepatocellular carcinoma caused by hepatitis B virus (2) and hepatitis C virus (18) complicated of liver cirrhosis. In viral liver diseases, SODs in the liver tissues were distributed to hepatocytes mainly in the pattern of cytoplasmic diffusion. The incidence of immunohistochemical Cu, Zn-SOD and Mn-SOD were 47.8% and 56.5% in chronic hepatitis, 93.3% and 86.7% in compensated liver cirrhosis, 11.1% and 22.2% in decompensated liver cirrhosis, respectively. The aggression of viral liver disease was accompanied with the decrease of SOD concentration in the liver tissues. Hepatocellular carcinoma cells were negative for Mn-SOD in all cases, and weakly positive for Cu, Zn-SOD in 2 out of 21 cases. Comparatively strongly positive SOD findings were obtained from normal regions neighboring carcinomas. A close relationship between the depletion of SOD in liver tissues and carcinogenesis in viral liver diseases was observed.

Carcinoma, Hepatocellular↗
PubMed1992

Possible relevance of lipid peroxidation and thromboxane production to the initiation and/or evolution of microangiopathy in non-hyperlipidemic type 2 diabetes mellitus.

To investigate the possible relevance of free radicals and prostanoids to the mode of initiation and/or evolution of microangiopathy in diabetes mellitus, we measured serum lipid peroxides (LPO), an accepted index of intravascular free radicals, and plasma 11-dehydrothromboxane B2 (11-dehydro-TXB2), a stable metabolite of vasoactive thromboxane A2 released from platelets, in 95 patients with normolipidemic type 2 (non-insulin-dependent) diabetes mellitus at different stages of the disease. In general, either LPO or 11-dehydro-TXB2 was significantly greater in the patients, as a group, than in the matched controls (3.82 vs. 2.65 nmol/ml, P < 0.01 for LPO; and 17.3 vs. 5.8 pg/ml, P < 0.01 for 11-dehydro-TXB2). In patients, both LPO and 11-dehydro-TXB2 increased according to the severity of their diabetic retinopathy. A highly significant positive correlation existed between the LPO values and 11-dehydro-TXB2 in the patients (r = 0.64, P < 0.0001), while there was no such relationship in the controls (r = 0.18, P = NS). No difference in serum levels of apolipoproteins A-I, A-II, B, C-II, C-III, or E was observed between the patients and controls. Short-term glycemic control (25 cal/kg of standardized body weight/day, for 8 weeks) resulted in a small but significant reduction in LPO (4.2 vs. 4.6 nmol/ml, control; P < 0.05) without alteration in 11-dehydro-TXB2. There was a tendency towards deterioration in LPO according to the improvement in glycemic control. These results appear consistent with the view that, in addition to LPO, the release of TXA2 from activated platelet in the human circulation could be an important factor for the initiation and/or evolution of microangiopathy in diabetic patients even when they are not apparently hyperlipidemic. Further, the results of the present study emphasize the notion that more tight control of serum lipids is worthy of serious consideration in preventing the advance of diabetic microangiopathy.

Aged↗
PubMed1992

Genomic organization of the mouse OSF-1 gene.

The mouse OSF-1 protein (also known as pleiotrophin, HB-GAM, HBGF-8, or HBNF) gene was isolated from a mouse genomic library and sequenced. OSF-1 is a 15-kD secreted protein specifically expressed in bone and brain, and is believed to play a role in brain development and osteogenesis. The mouse OSF-1 gene consists of at least 5 exons and 4 introns and spans > 32 kb. Computer analysis of approximately 4 kb of 5'-flanking sequence of the OSF-1 gene revealed two candidate promoter regions. One candidate promoter contains a thyroid hormone/retinoic acid-responsive element and the other contains two glucocorticoid-responsive elements. DNA sequence analysis of novel OSF-1 cDNA clones indicates that two promoters can be utilized in MC3T3-E1 osteoblastic cells. The overall organization of the mouse OSF-1 gene is similar and the locations of the three exon-intron junctions within the coding region are identical to the mouse gene encoding the differentiation-related factor midkine (MK). Based on this similarity and on the high degree of nucleotide sequence homology (approximately 55%) of mouse OSF-1 and mouse MK, we conclude that OSF-1 and MK are generated from a common ancestral gene and are members of a family of structurally and probably functionally related proteins.

Amino Acid Sequence↗
PubMed1992

Distribution of putative odour receptor proteins in olfactory epithelium.

To investigate immunohistochemically the spatial localization of putative odour receptor proteins, we synthesized a polypeptide which corresponds to a region of a putative odour receptor protein, I3, and raised an antibody to the peptide. In rat olfactory epithelium, the antibody specifically recognized cilia of a small subset of olfactory receptor neurons, suggesting that the odour receptor protein is localized selectively in the cilia. Olfactory receptor neurons having immunoreactive cilia were distributed sparsely throughout the epithelium. This suggests that receptor neurons expressing a similar odour receptor protein are probably distributed similarly in the epithelium.

Amino Acid Sequence↗
PubMed1992

A degenerative lesion of the approach to the atrioventricular node producing second-degree and third-degree atrioventricular block.

We report a case of a degenerative approach lesion in an 83-year-old male with diabetes mellitus, hypertension, and ischemic heart disease. His ECGs changed from first-degree atrioventricular (AV) block 14 years ago, to third-degree AV (A-H) block. A pacemaker was implanted for bradycardia. He died 4 years later from heart and renal failure. Serial sections through the conduction system revealed total depletion and fatty replacement of the atrial muscle at the approaches to the AV node.

Aged↗
PubMed1992

Use of prostaglandin E1 (lipo-PGE1) to treat Raynaud's phenomenon associated with connective tissue disease: thermographic and subjective assessment.

Four patients with connective tissue disease who had been suffering from severe Raynaud's phenomenon were treated with an intravenous infusion of prostaglandin E1 (PGE1) and its effectiveness was assessed by thermography and a questionnaire approach. PGE1 in a lipid microsphere formulation (lipo-PGE1) produced a significantly greater increase in lesional skin temperature compared with treatment with PGE1 clathrated in alpha-cyclodextrin 12 months previously in the same group of patients. These results were supported by the subjective assessment obtained from the patients by questionnaire.

Adolescent↗
PubMed1992

Age-related differences in the inhibition of neuropathy target esterase and susceptibility to triphenyl phosphite-induced delayed neurotoxicity in chickens.

Triphenyl phosphite (TPP)-induced delayed neurotoxicity, which is thought to resemble but somewhat differ from classical organophosphate-induced delayed neurotoxicity (OPIDN), is known to be age-dependent. The relationship between clinical appearance and histopathological lesions, and the inhibition of neurotoxicity target esterase (NTE) in nervous tissues were compared in young and adult chickens after i.v. administration of TPP. NTE inhibition by TPP in vitro was also compared between the two age groups. Fourteen days after i.v. administration of TPP (50 mg/kg), adult chickens (24 months old) showed obvious histopathological lesions as well as obvious clinical neurological signs. On the other hand, young chickens (65 days old) showed few histopathological lesions and only marginal neurological signs. NTE activity in brain, spinal cord, and sciatic nerves was inhibited in a dose-dependent manner in both age groups. While inhibition tended to be mild in the younger chickens, the level of activity was less than 30% of the normal value in all three tissues at 24 hours after administration of 50mg/kg of TPP (14% vs. 8% in brain, 15% vs. 9% in spinal cord and 13% vs. 14% in sciatic nerves). Recovery of NTE activity in the sciatic nerves was faster in the younger chickens. The IC50 of TPP on brain (6.67 vs. 6.76 x 10(-8)M) and spinal cord NTE (1.05 vs. 1.53 x 10(-7)M) was almost the same in the two age groups. These results confirmed age-specific susceptibility to TPP, not only clinically but also histopathologically, and, suggested that the differences in both TPP metabolism and NTE recovery are related to and/or contribute to this age specificity. Judging from the age specificity and the figure of NTE inhibition, the delayed neurotoxicity produced by an i.v. administration of TPP is virtually identical to classical organophosphate-induced delayed neurotoxicity. Hydrolytic products may produce additional effects characteristic of TPP-induced neurotoxicity observed after an s.c. dose.

Age Factors↗
PubMed1992

Tuberculous peritonitis with extraordinarily high serum CA125.

A 74-year-old woman who was admitted for the evaluation of ascites showed a marked elevation of serum CA125 level. Laparoscopy revealed the presence of numerous white modules (approximately 5 mm diameter) on the peritoneum suggestive of tuberculomas. A biopsy specimen showed epithelioid cells and Langhans-type giant cells. Following the administration of diuretics, the level of serum CA125 decreased concomitantly with the decrease in the volume of peritoneal fluid. The level of CA125 decreased further with the administration of antituberculosis agents. Clinical specimens were negative for mycobacteria. We conclude that the elevated serum level of CA125 was due to peritoneal tuberculosis and consequent ascites. Thus, tuberculous peritonitis should be considered in the presence of an unexplained, abnormally elevated serum level of CA125.

Aged↗