Biomedical subjects

Y Katoh

Publications and source records attributed to Y Katoh.

At least 127 records · Page 7Linked to original sources

PubMed1992

Results of expansive laminoplasty for lumbar spinal stenosis in active manual workers.

Expansive laminoplasty was done on 18 selected patients with lumbar spinal canal stenosis who were active manual workers and 2 patients with cauda equina tumors from 1982 to 1990. Postoperative follow-up on the initial 10 cases of spinal stenosis was 1-7 years (mean, 3 years). Using computed tomography, the spinal canal was found to be enlarged with a nearly rectangular shape, and the mean percent enlargement was 119% (1.9 cm2). Spinal stability also was reinforced. The preoperative mean evaluation score (Japanese Orthopaedic Association score) was 10.4 (full scale, 29). The mean score improved to 24 postoperatively (mean percent improvement, 73%). These findings did not change during the long follow-up, and the satisfactory results were maintained.

Adult↗

PubMed1992

Influence of morphologic factors on calcium-containing stone formation.

Pathogenesis of urolithiasis cannot be explained only by metabolic disorder. In the present study, morphologic differences of the renal pelvic-caliceal system (PCS) were examined on both the stone and normal sides in calcium-containing stone formers. The results indicated that as compared to the normal side, the urine flow in the PCS was stagnant or not straight on the stone side even in the same individual, showing unfavorable conditions for stone formation. It is therefore considered that morphologic disorders of the urinary tract may be one of the causes for stone formation.

Adult↗

PubMed1992

Interleukin-1 of cholesteatomatous keratinocytes.

Interleukin-1 (IL-1) has been thought to be one of the essential cytokines mainly produced by macrophages. It has recently been reported that epidermal keratinocytes produce IL-1, and attention is being paid to local immune reactions mediated with this cytokine. Interleukin-1 not only activates lymphocytes, but also acts as an osteoclast-activating factor. In this study, we used immunohistochemistry and immunoblotting on cholesteatomatous epithelium with anti-IL-1 alpha antibody and anti-IL-1 beta antibody. Next, the relationship of cholesteatomatous debris to the production of IL-1 by keratinocytes was evaluated. Highly concentrated IL-1 alpha was found in the cholesteatomatous epithelium, especially in the basal cell layer. The intensity of IL-1 beta staining was weaker than that of IL-1 alpha staining. In the immunoblotting study, the 31 kd band, an intracellular immature precursor molecule, was identified. The production of IL-1 alpha from keratinocytes was augmented to a greater degree by cholesteatomatous debris than by lipopolysaccharide or keratin. The keratinocytes did not produce IL-1 beta. These findings suggest that IL-1 alpha is derived from cholesteatomatous keratinocytes. Interleukin-1, mainly IL-1 alpha, from the stimulated cholesteatomatous keratinocytes may be an important factor in the markedly increased bone resorption observed in cholesteatoma.

Blotting, Western↗

PubMed1992

Molecular mechanism of hypertrophied failing heart--abnormalities of the diastolic properties and contractility.

The clinical syndrome of heart failure occurs as a consequence of the limitation of compensatory mechanisms, such as cardiac hypertrophy. To clarify transcriptional changes in specific genes in failing hearts, we examined the expression of cardiac Ca(2+)+Mg(2+)-dependent ATPase in the sarcoplasmic reticulum and transforming growth factor beta genes in the ventricles of rat hypertrophied heart, and the expression of guanine nucleotide-binding protein and "fetal" contractile protein genes in the ventricles of cardiomyopathic Syrian hamsters of Bio14.6. Northern blot analysis of total cellular RNA revealed that the mRNA levels of Ca(2+)+Mg(2+)-dependent ATPase were decreased by pressure overload and became 32% of sham in 1 month, and were correlated with corresponding protein levels. Transforming growth factor beta mRNA, a potent activator of collagen synthesis, was increased by pressure overload. The expression levels of the Gs alpha mRNA, which stimulated the adenylate cyclase, in Bio14.6 ventricles were lower than the levels in ventricles of the F1B hamster strain, and decreased as the stage of cardiomyopathy progressed. Moreover, re-expression of fetal mRNA was observed in the ventricle of cardiomyopathic Syrian hamsters of the Bio14.6 strain. These results indicate that reprogramming of cardiac gene expression both of myofibrillar and nonmyofibrillar components might occur in the failing heart.

Animals↗

PubMed1992

[Multiple myeloma with a mass formation in a pacemaker pocket].

A 74-year-old female was diagnosed as having multiple myeloma in August 1989 and was treated with combined vincristine, melphalan and prednisolone. Subsequently, she was followed followed up in the outpatient clinic using interferon-alpha. On August 6, 1990, she had a transvenous demand pacemaker inserted because of severe atrioventricular block. The pulse generator was placed in a subcutaneous pocket in the left pectoral area. On February 3, 1991, she developed a mass overlying the pulse generator. This tumor was diagnosed as plasmacytoma by histological examinations. A myelogram showed 5.1% plasma cells with 5.5 x 10(4) nucleated cells/microliter. The amounts of serum protein and IgA M protein were 6.8 g/dl and 1.8 g/dl, respectively. The tumor responded to combined chemotherapy, but reenlarged to the initial size 3-4 weeks later. On August 6, 1991, this tumor, including the pulse generator was removed. By October 1991, the patient had systemic subcutaneous tumors and a right maxillary tumor suggesting the aggressive phase. On December 19, 1991, she died due to cardiac failure. In this paper the discussion focussed on the etiopathogenesis of plasmacytoma arising in the region of pulse generator pockets.

Aged↗

PubMed1991

N-methyl-D-aspartate, quisqualate and kainate receptors are all involved in transmission of photic stimulation in the suprachiasmatic nucleus in rats.

In order to clarify the neuronal transmission mechanism of photic stimulation in the suprachiasmatic nucleus (SCN), the effects of agonists and antagonists for excitatory amino acid receptors on N-acetyltransferase (NAT) activity in the pineal gland were observed following the microinjection of drugs into both sides of the nuclei. N-Methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, and kainate (which are selective agonists for three different subtypes, i.e. NMDA, quisqualate and kainate receptors, respectively) significantly decreased NAT activity similarly to the suppressive effect of light. Moreover, compared with a control group, all the groups pretreated with a selective competitive antagonist for NMDA receptor (D-2-amino-5-phosphonovalerate or 3-((+-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonate), or a selective non-competitive antagonist for non-NMDA receptors (Joro spider toxin-3 or 1-naphthylacetyl spermine) partially blocked the suppressive effect of photic stimulation on NAT activity. These results suggest that NMDA, quisqualate and kainate receptors are all involved in mediating photic stimulation in the SCN.

Acetyltransferases↗

PubMed1991

Mechanical loading stimulates cell hypertrophy and specific gene expression in cultured rat cardiac myocytes. Possible role of protein kinase C activation.

To examine the molecular mechanisms by which mechanical stimuli induce cardiac hypertrophy and specific gene expression, we cultured rat neonatal cardiocytes in deformable dishes and imposed an in vitro mechanical load by stretching the adherent cells. Myocyte stretching increased total cell RNA content and mRNA levels of c-fos and skeletal alpha-actin. Nuclear run-off transcription assay revealed that this increase in c-fos mRNA level by stretching at least partially reflects changes in the transcriptional status. The transfected chloramphenicol acetyltransferase gene linked to upstream sequences of the fos gene indicated that sequences containing a serum response element were required for efficient transcription by stretching and that sequences containing a cAMP/calcium response element might not be involved in the c-fos response to myocyte stretching. The accumulation of c-fos mRNA by stretching was suppressed by protein kinase C inhibitors at the transcriptional level and inhibited markedly by down-regulation of protein kinase C. Moreover, myocyte stretching increased inositol phosphate levels, and activation of protein kinase C by phorbol esters stimulated the expression of c-fos and skeletal alpha-actin genes. These findings suggest that mechanical stimuli (myocyte stretching) might directly induce cardiac hypertrophy and specific gene expression possibly via protein kinase C activation.

Actins↗

PubMed1991

Histochemical and ultrastructural observations on brown degeneration of human intervertebral disc.

Thirty-eight fresh human intervertebral discs collected during anterior interbody fusion surgery were histochemically and ultrastructurally analyzed for pigments. Macroscopically, five stages of degeneration were classified according to the color, fibrosis, and fragility of the nucleus pulposus of the discs. In order to demonstrate lipofuscin granules, specimens were subjected to special staining procedures, including carbol fuchsin lipofuscin stain, the Schmorl's reaction, and autofluorescence. Lipofuscin granules were distributed from the inner layer of the annulus fibrosus to the nucleus pulposus. Such granules were numerous in cases of slight or severe degeneration, whereas fewer granules were found in cases of moderate degeneration. However, the stage of macroscopic degeneration of the intervertebral disc did not necessarily correlate with the incidence of lipofuscin granules. By ultrastructural observation, the morphological features of the components of the intervertebral disc and the ultrastructure of the lipofuscin granule were clarified. The ultrastructure of the "brown degeneration" disc exhibited markedly increased amorphous electron-dense bodies located among collagen fibrils in the matrix.

Adult↗

PubMed1991

Relationship between metabolic acidosis and calcium phosphate urinary stone formation in women.

The relationship between the degree of metabolic acidosis and calcium phosphate stone formation was studied. Furthermore, the reasons why renal tubular acidosis (RTA) and primary hyperparathyroidism (PHPT) dominantly occur in women, and female stone formers more often produce calcium phosphate stone are discussed. Blood was slightly more acidotic in women than in men in both the urolithiasis and the control groups. Likewise, blood was significantly more acidotic and urinary pH significantly higher in patients with PHPT. Patients with RTA had severe metabolic acidosis, and urinary pH was highest among all groups. Calcium phosphate concentration was significantly higher in women than in men, and was also higher in patients with PHPT than in those with urolithiasis. All patients with RTA had pure calcium phosphate stones. The reasons why females are more acidotic and have more calcium phosphate in stones are suspected to be related to progesterone and urinary tract infection.

Acidosis, Renal Tubular↗

PubMed1991

Epidemiology of urolithiasis in the elderly.

To estimate the epidemiology of upper urinary stones in the elderly, a total of 1,957 patients (1,349 men and 608 women) with urolithiasis were studied. The ratio of men to women was approximately 3:1 in middle-aged (between 30 and 59 years), 1:1 in young (29 or younger) and 1:1 in old patients (60 or older). Compared with the age distribution of the entire Japanese population, the incidence of urinary stones was very low in both male and female children, twice as high in middle-aged men, slightly higher in middle-aged women, and equal or slightly lower in the male and female elderly. Stones of calcium oxalate and uric acid occurred more frequently and those of calcium phosphate and struvite less frequently in men than in women. This tendency was especially obvious in the middle-aged. In the old generation, calcium oxalate stones occurred almost equally in men and women. Results of urinary stone analysis were similar among men of the three generations, although the incidence of uric acid stones increased with patient age. In women, however, the incidence of calcium oxalate was higher in the young and old generations, while that of calcium phosphate was higher in the middle-aged.

Adolescent↗

PubMed1991

Effects of ethane-1-hydroxy-1, 1-diphosphonate on cell differentiation, and proteoglycan and calcium metabolism, in the proximal tibia of young rats.

The effects of ethane-1-hydroxy-1, 1-diphosphonate(EHDP) on cell differentiation, and on the metabolism of proteoglycan and calcium in the epiphyseal plate and metaphysis of rats were investigated through histology and autoradiograms of [35S]-sulfate, 45Ca, and [3H]-thymidine. Suppression of bone resorption in the metaphysis due to low dose EHDP administration was associated with a proliferation of osteoclasts with an increased number of nuclei. High dose EHDP induced enlargement of the hypertrophic zone of the epiphyseal plate and suppression of calcification of the cartilage matrix. This change had a significant association not only with the suppression of chondroitin sulfate synthesis and the degradation in the cartilage matrix, but also with the suppression of growth and differentiation of chondrocytes. Calcification was also inhibited in the metaphysis, and growth and differentiation from undifferentiated mesenchymal cells to osteoblasts, osteocytes, and osteoclasts were also suppressed by high dose EHDP.

Animals↗

PubMed1991

Optical determination of impulse conduction velocity during development of embryonic chick cervical vagus nerve bundles.

1. Employing an optical method for multiple-site simultaneous recording of electrical activity, we have determined the conduction velocity in cervical vagus nerve bundles isolated from 5- to 21-day-old chick embryos, and investigated its developmental changes. 2. The preparations were stained with a voltage-sensitive merocyanine-rhodanine dye (NK2761), and action potential- (impulse-) related optical signals were elicited by brief stimuli applied to the end of the vagus nerve bundle with a suction electrode. Optical signals were recorded simultaneously from many contiguous regions using a 12 x 12-element photodiode array. 3. The optical signals spread with small delay from the site of stimulation. From the relationship between the delay and distance from the current-applying electrode, conduction velocities were estimated in each tested preparation: the conduction velocity was very small and increased monotonically from about 0.1 m s-1 at 5 days embryonic age to about 0.4 m s-1 by hatching. The increase in the conduction velocity was closely related to a developmental increase in the diameter of the vagus nerve bundle. 4. In addition, we have examined the spread of electrotonic potentials. The space constant was very small (200-450 microns) and increased as development proceeded. 5. Compound optical action signals having two distinct components were also recorded. They often appeared to be concentrated in the preparations from 8- to 12-day-old embryos. The conduction velocity of the second component was slower than that of the first. We suggest that appearance of the second component reflects degeneration of a subset of axons resulting from 'neural cell death' during the development of the vagus nerve.

Action Potentials↗

PubMed1991

Immunofluorescent study on the interaction between collagen and calcium oxalate crystals in the renal tubules.

The interaction of calcium oxalate crystals and renal tubular cells was studied. Rat renal collecting tubular cells were cultured and immunologically stained with anti-type-IV collagen antiserum (type-IV collagen exists in renal tubular basement membrane). When renal tubular cells and calcium oxalate crystals were mixed, clumps were formed. These clumps were examined by immunological staining with anti-type-IV collagen antiserum. In another series of experiments, calcium-containing crystals were found to be adsorbed onto mucous threads and cast-like materials, although no such adsorption was observed on squamous cells. These absorbed materials interacted with anti-type-IV collagen antiserum. These results suggest that collagen in the renal tubular basement membrane may act as matrix in urinary stone formation.

Animals↗

PubMed1991

Mechanisms of cardiac hypertrophy and injury--possible role of protein kinase C activation.

To examine the molecular mechanisms by which mechanical stimuli induced cardiac hypertrophy and injury, we cultured rat neonatal cardiocytes in deformable dishes and imposed an in vitro mechanical load by stretching the adherent cells. Myocyte stretching increased total cell RNA content and mRNA levels of c-fos. Marked accumulation of c-fos mRNA followed increases in intracellular Na+ and protein kinase C activation. The accumulation of c-fos mRNA by cardiocyte stretching was suppressed by protein kinase C inhibitors but not by stretch channel blockers. Moreover, myocyte stretching increased inositol phosphate levels, and activation of protein kinase C by phorbolesters stumulated the expression of c-fos. We also examined TGF beta expression in the heart. TGF beta is known to be stimulated by protein kinase C activation, and the mRNA level of TGF beta was increased in in vivo heart by pressure overload. Furthermore, collagen synthesis was stimulated by TGF beta in cultured fibroblasts from hearts. These findings suggest that hemodynamic overload may stimulate cardiac hypertrophy and induce cardiac injury (fibrosis) through protein kinase C activation.

Animals↗

PubMed1991

[Results of Kock pouch construction fully utilizing an auto-suture instrument].

From March 1987 to the end of February 1991, we performed Koch pouch construction as a urinary diversion on 20 patients who had undergone radical cystectomy due to bladder cancer. The operation was done according to the method of Skinner et al. We fully utilized an auto-suture instrument to ensure safe and stable suturing of the ileum and to shorten the operating time. It was of great concern that the staples placed at several portions might cause stone formation or aggravate infection. However, stone formation was observed only in one patient (5%) at the tip of a nipple valve in which a staple became the nucleus of the stone. Staples are usually not regarded as an obstacle as they are usually covered by the mucous membrane. In all patients, the maximum capacity of the pouch was more than 500 ml, intra-pouch pressure was kept low even when the pouch was inflated up to the maximum capacity, and reflux of urine into the upper urinary tract was not observed. As for complications, there was a slight degree of obstructive uropathy in 4 patients (20%), difficulty in catheter insertion was noted in 3 patients (15%), and stress incontinence-like urinary leakage was present in one patient when the capacity exceeded 500 ml. However, there were no complications which necessitated reoperation. In terms of blood chemistry, although there was a tendency towards a slight increase in BUN or hyperchloremia, no specific treatment was necessary as far as the kidney function was normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Preparation of a standard diet for out-patients in the study of lithogenesis].

With the development of extracorporeal shock wave lithotripsy treatment, the duration of hospitalization for stone patients fortunately has become shorter. However, a detailed analysis of lithogenesis is not possible during such patients' short hospital stays. We prepared a standard diet to be eaten at home for investigation of lithogenesis at the out-patient clinic. This diet was nutritionally well-balanced and contained the following: energy: 2000 Kcal, total protein: 70-75 g, animal protein: 30-35 g, carbohydrate: 510 g, fat and oil: 50-60 g, calcium: 600-630 mg and magnesium: 320 mg. The urine of 24 male patients with stones on a free diet and the same patients after 3 days on the standard diet was analyzed for urea-nitrogen, uric acid, sodium, calcium, phosphorus, magnesium, citric acid and oxalic acid. The results were compared with those in 17 healthy male subjects who were eating the standard diet (controls). It was found that 66% of hypercalciuria (greater than = 300 mg/day) on a free diet became normocalciuria on the standard diet. The hypercalciuria was therefore thought to be of dietary origin. Moreover, urinary excretion of urea nitrogen, uric acid, sodium and phosphorus by patients remarkably decreased after 3 days on the standard diet, which was not different from that of controls. These results suggest that the standard diet at home is useful in the screening of hypercalciuria and also quite adequate for patients with stones.

Adult↗

PubMed1991

Untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum.

An adult case of untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum in the thoracic region is reported and discussed with regard to the calcium metabolism and the ligamentous ossification. Factors influencing ossification of the ligamentum flavum may be mechanical stress on the spine and an increase in calcium retention.

Adult↗

PubMed1991

Electron microscopic identification of the intracellular secretion pathway of human G-CSF in a human tumor cell line: a comparative study with a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA.

Using monoclonal antibodies specific for human granulocyte colony-stimulating factor (G-CSF), intracellular localization of G-CSF in a G-CSF-producing human tumor cell line (CHU-2) and its ultrastructural characters were described and compared with those of a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA. The CHU-2 line, which was derived from a poorly differentiated squamous cell carcinoma of the oral cavity, preserved the character of a poorly differentiated squamous cell carcinoma. In the CHU-2 cell line, there were few cells immunohistochemically positive for G-CSF under light microscopic analysis despite the high transcription level of G-CSF cDNA and secretion of G-CSF that were comparable with cDNA-transfected IA1-7 cells. Using electron microscopy, the reaction products were localized mainly in the perinuclear space (PNS) and rough endoplasmic reticula (RER) without dilation of the cisternae, but they were very rarely found in the Golgi complex and not at all in other intracellular organelles. In contrast, most cells were positive for G-CSF in the IA1-7 cell line. Reaction products in this cell line were also demonstrated in the PNS and RER without dilation of the cisternae. These immunohistochemical findings, in conjunction with the results of Western and Northern blot analysis, suggested that G-CSF was secreted via the PNS and RER without intracellular retention.

Animals↗