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Biomedical subjects

K Hoshi

Publications and source records attributed to K Hoshi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Age-related changes in bone mineral density and serum bone-related proteins in premenopausal and postmenopausal Japanese women.

The purpose of this cross-sectional study was to characterize the age-related change in bone metabolism during the pre- and postmenopausal periods, and to define the standard levels of three serum markers of bone metabolism, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), carboxyterminal propeptide of type I procollagen (PICP), and bone gla protein (BGP), in Japanese adult women. The bone mineral density (BMD) of the lumbar spine (L2-L4) and the serum levels of ICTP, PICP and BGP were determined in a total of 207 healthy Japanese women (108 premenopausal and 99 postmenopausal). The lumbar BMD decreased significantly with increasing age not only in postmenopausal women (P<0.001) but also in premenopausal women (P=0.014). There was a clear gap in the serum levels of ICTP, PICP and BGP between the premenopausal and postmenopausal group (P<0.001), but those were absolutely the same within each group except for ICTP in the postmenopausal women. These findings and the values of serum ICTP, PICP and BGP in pre- and postmenopausal women obtained in this study are expected to be very useful for treatment of postmenopausal osteoporosis.

Adult↗
PubMed2000

Prenatal confirmation of periventricular leukomalacia in a surviving monochorionic-diamniotic twin after death of the other fetus: a case report.

A 30-year-old woman was found to be carrying monochorionic-diamniotic twins at 7 weeks of gestation. The growth-retarded fetus died at 21 weeks of gestation. At 28 weeks of gestation, periventricular leukomalacia was detected in the brain of the surviving fetus by transvaginal ultrasonography. A female baby presenting with microcephaly was born at 39 weeks of gestation, and CT of the brain showed microcephaly and marked hydrocephalus. At 12 months of age, the surviving infant presented with severe physical growth retardation, and frequent episodes of clonic convulsions.

Adult↗
PubMed2000

A pregnancy complicated with Fechtner syndrome: a case report.

A 21-year-old woman was diagnosed with Fechtner syndrome at 15 weeks gestation. She had a familial history of this disorder; her mother, two siblings and maternal grandmother were also affected. She presented with neither bleeding from the genital tract nor symptoms suggestive of placental abruption. Labor progressed uneventfully and resulted in the birth of a healthy female infant weighing 3436 g at 41 weeks of gestation. The puerperium was uneventful for both mother and infant.

Adult↗
PubMed2000

Cessation of cerebral hemorrhage recurrence associated with corticosteroid treatment in a patient with cerebral amyloid angiopathy.

We report the case of a 65 year old female patient with biopsy-proven cerebral amyloid angiopathy (CAA). She experienced intracerebral hemorrhages 4 times during 23 days but these serious strokes did not recur after corticosteroid therapy was started and her condition greatly improved. Since high titers of antinuclear antibodies and elevated erythrocyte sedimentation rate were found in her serum, she may have an inflammatory disorder involving amyloid-laden cerebral vessels. This is the first report showing the usefulness ofcorticosteroid for the treatment of CAA-related cerebral hemorrhages. Additionally, the concentrations of Abeta40 and Abeta42 in the CSF of this patient decreased rapidly after the use of corticosteroid, and ultimately fell far below normal values.

Adrenal Cortex Hormones↗
PubMed2000

[Anesthetic management of a patient with hemophilia A for left modified Blalock-Taussig shunt].

We gave anesthesia to a patient with hemophilia A for left modified Blalock-Taussig shunt. The patient was a twenty five-day-old boy with pulmonary atresia. We performed the bolus injection test of factor VIII concentrate in preoperative period. His factor VIII activity increased from 9.3 to 113.3% after a bolus injection of 165 units. To keep his factor VIII activity above 80% in perioperative period, a bolus of 125 units of recombinant factor VIII concentrate was injected at anesthesia induction, 125 units 2 hours after the start of the operation, and 125 units 6 hours after the end of the operation. Factor VIII activity 2 hours after anesthesia induction increased only 37.8%, and we had to infuse recombinant factor VIII concentrate additionally. We measured factor VIII activity during operation, and he finally received total of 415 units of factor VIII concentrate. Hydroxyethyl starch infusion, blood transfusion and bleeding in the perioperative period might have caused the factor VIII activity to decrease beyond our expectation. We should infuse factor VIII concentrate properly measuring the factor VIII activity during this operation.

Anastomosis, Surgical↗
PubMed2000

Newt prolactin and its involvement in reproduction.

The amino acid sequence of newt (Cynops pyrrhogaster) prolactin deduced from the nucleotide sequence of its cDNA showed a relatively high homology with sequences of chicken and sea turtle prolactins as well as with those of anuran prolactins. Cynops prolactin receptor transcripts were detected in various tissues and organs, suggesting that prolactin plays multiple roles in urodeles. Urodele prolactin was purified from the pituitaries of C. pyrrhogaster. Antiserum against this prolactin was used for radioimmunoassay of plasma prolactin and immunoneutralization experiments. Endogenous prolactin was shown to induce migration to water, courtship behavior, and cessation of spermatocytogenesis in the Cynops newt. The hormone was found to be involved in the development of cloacal glands such as the lateral and abdominal glands, growth of the tail and Mauthner neurons, secretion of oviducal jelly, and enhanced synthesis of a female attracting pheromone (sodefrin), and responsiveness of the olfactory epithelium to sodefrin. In most of these cases, prolactin was found to act synergistically or antagonistically with sex steroids. We also discovered that hypersecretion of prolactin in the newts subjected to cold temperature was induced by hypothalamic stimulation rather than release from hypothalamic inhibition.

Amino Acid Sequence↗
PubMed2000

Ultrastructural, cytochemical, and biophysical aspects of mechanisms of bone matrix calcification.

Primary calcification in embryonic ossification occurs as follows: crystallization within matrix vesicles, formation of calcified nodules, and finally the establishment of expansive calcified matrix. However, the participation of the matrix vesicles in other types of bone calcification, such as bone formation during bone remodeling in adults has not been examined sufficiently. We introduce our recent observations on the presence of matrix vesicles in aged bones. In addition, although it is well known that the extracellular fluid supersaturates the calcification crystal, hydroxyapatite, the specific mechanisms by which bone matrix calcify remain unclear. In order to further approach the mechanisms of bone matrix calcification, we also review ultrastructural and localizational alterations of the matrix organics according to the progression of calcification, and an evaluation of mineral micro-environment in the calcifying sites by energy-filter transmission electron microscopy.

Animals↗
PubMed1999

Nuclear vitamin K2 binding protein in human osteoblasts: homologue to glyceraldehyde-3-phosphate dehydrogenase.

The importance of vitamin K in bone metabolism has been suggested previously. The binding protein of vitamin K2 (menatetrenone, 2-methyl-3-all-trans-tetraphenyl-1,4-naphthoquinone, menaquinone-4), found in nuclear extract of human osteoblasts, binds to vitamin K1 and K2, but not K3. Since the binding protein does not bind to other steroids or vitamins, such as hydrocortisone, vitamin A, 1,25(OH)2vitamin D3, trolox (a derivative of vitamin E), and warfarin, a specific binding protein to vitamin K1 and vitamin K2 in osteoblasts was suggested. The size of the specific binding protein was revealed to be 6S by sucrose density gradient and about 40,000 daltons by SDS-PAGE. Twenty amino acid residues from the N-terminal were the same as human glyceraldehyde-3-phosphate dehydrogenase (GAPDH), but the 21st residue, alanine, was replaced with serine. The binding protein was precipitated with anti-human GAPDH antibody, and authentic human GAPDH could bind vitamin K2. We propose that the nuclear binding protein for vitamin K2 exists in nuclei similarly to other vitamin receptors and that the molecular structure is very close to human GAPDH.

Amino Acid Sequence↗
PubMed1999

Comparison between in vivo and in vitro pharmacokinetics of succinylcholine in humans.

PURPOSE: To compare the in vivo and in vitro pharmacokinetics of succinylcholine (SCh) in humans. METHODS: A bolus of SCh 1 mg.kg(-1) (n = 7) or 2 mg.kg(-1) (n = 11) was given to 18 patients anesthetized with thiopental. Arterial blood samples for determination of in vivo SCh concentrations were collected every 30 s for 5 min. Another 20-ml blood sample was obtained before induction of anesthesia for determination of in vitro SCh. Concentrations of SCh were measured by high-performance liquid chromatography. In vivo and in vitro concentrations of SCh vs time data were analyzed by the one-compartment model. RESULTS: The respective in vivo and in vitro pharmacokinetic parameters (SCh 1 mg.kg(-1) vs SCh 2 mg.kg(-1)) were as follows: Plasma clearance was 4.17 +/- 2.37 and 1.85 +/- 0.28 l.min(-1), P < 0.05, vs 2.91 +/- 2.01 and 1.27 +/- 0.43 l.min(-1), P < 0.05. Elimination half-life was 25.4 +/- 10.6 and 47.4 +/- 5.4 s, P < 0.002 vs 26.3 +/- 10.0 and 75.2 +/- 21.8 s, P < 0.00005. CONCLUSION: These results suggest that the rapid disappearance of SCh from the circulation is due to diffusion out of the blood vessels rather than to enzymatic hydrolysis.

Journal Article↗
PubMed1999

Participation of angiotensin II and bradykinin in contractile function in dog stunned myocardium.

We examined the effects of enalapril and 4'-[(1, 4'-dimethyl-2'-propyl-[2,6'-bi-1H-enzimidazole]-1'-yl)methyl]-[1, 1'-biphenyl]-2-carboxylic acid (BIBR-277), an angiotensin II receptor antagonist, on contractile dysfunction in the stunned myocardium. Dogs were subjected to 20-min ligation of the coronary artery, followed by 60-min reperfusion. Saline, enalapril (1 mg/kg or 3 mg/kg), or BIBR-277 (3 mg/kg) was injected i.v. 10 min before ligation. D-Arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L-prolylglycyl -3-(2-thi enyl)-L-alanyl-L-seryl-D-1,2,3, 4-tetrahydro-3-isoquinolinecarbonyl-L-(2alpha, 3beta, 7abeta)-octahydro-1H-indole-2-carbonyl-L-arginine (Hoe-140), a bradykinin B(2) receptor antagonist, at 300 microg/kg was injected i. v. 10 min before drug injection. Contractile function was assessed on the basis of percentage segment shortening (%SS). ATP levels were measured in 60-min reperfused hearts. %SS significantly decreased during ischemia, and recovered during reperfusion, although the %SS was significantly less than the pre-ischemic level. Both enalapril at either dose and BIBR-277 significantly enhanced %SS recovery during reperfusion, an effect which was associated with a tendency toward energy preservation. Hoe-140 completely abolished the effect of enalapril at either dose, while it did not modify that of BIBR-277. Inhibition of angiotensin II formation and bradykinin breakdown may be separately related to the improvement of myocardial stunning.

Adenosine Triphosphate↗
PubMed1999

Creutzfeldt-Jakob disease with florid-type plaques after cadaveric dura mater grafting.

BACKGROUND: Many reported cases of iatrogenic Creutzfeldt-Jakob disease (CJD) developed after grafting cadaveric dura mater contaminated with CJD prions (dura-associated CJD). They are known to be clinicopathologically similar to sporadic CJD. We report herein 2 autopsy cases of dura-associated CJD with atypical clinicopathological features. PATIENTS: Two patients presented with progressive ataxia and mental deterioration 10 or 11 years after neurosurgical treatment with cadaveric dural grafting, which led to their deaths at 8 and 17 months, respectively, after onset. RESULTS: The cases were clinically atypical in exhibiting no or late occurrence of myoclonus and periodic synchronous discharges on electroencephalographic studies. They were pathologically unique in several aspects. The most striking feature was the presence of many prion protein (PrP) plaques in multiple areas in the brain. Some of them were the "florid" type surrounded by a zone of spongiform changes known to be a hallmark for the new variant CJD. The distribution of spongiform degeneration was also unique in that it was intense in the thalamus, basal ganglia, and the dentate nuclei of the cerebellum but milder in the cerebrum. There were no mutations in the PrP gene of the patients. There was no major difference in the size and glycoform pattern between the abnormal isoform of PrP extracted from the brain tissue from the dura-associated cases of CJD and that from a sporadic case of CJD. CONCLUSIONS: These 2 cases are clinicopathologically distinct from typical dura-associated cases of CJD. They may be a subtype with florid-type plaques in dura-associated CJD.

Aged↗
PubMed1999

Amniotic fluid alpha-fetoprotein testing in native Japanese women.

Owing to differences in maternal serum alpha-fetoprotein, human chorionic gonadotrophin and oestriol levels between native Japanese and Caucasian women screened in this laboratory, a study was conducted to measure amniotic fluid alpha-fetoprotein (AFAFP) levels in native Japanese pregnancies. When the native Japanese AFAFP levels were compared with a United States (non-Black) population, the Japanese medians did not decrease as rapidly over the 14 to 22 weeks of gestation period investigated. At 14 weeks, the difference was negligible, graduating to a difference of 20 per cent by 22 weeks' gestation. Native Japanese pregnancy AFAFP levels should be interpreted based upon population data from that group alone. From these findings, prenatal screening laboratories should be encouraged to collect preliminary data for comparison before screening is initiated for a defined ethnic group.

Amniocentesis↗
PubMed1999

Morphological characterization of skeletal cells in Cbfa1-deficient mice.

To clarify the mechanisms by which core-binding factor-alpha1 (Cbfa1), an essential transcription factor in osteogenesis, functions in osteoblast matrix formation, as well as in chondrocyte differentiation and osteoclastic bone resorption, Cbfa1-deficient embryonic mice were investigated ultrastructurally and histocytochemically at 18.5 days postcoitum. In homozygotic mice, both endochondral and intramembranous ossification were arrested, although bone tissue had already formed at this stage in the wild type. The tibiae of homozygotic mice were characterized by calcified cartilage and alkaline phosphatase (ALP)-positive perichondrium, whereas membranous structures indicating the presence of ALP activity in the lateral portion were observed in the calvariae, rather than the bone tissue. Most of the ALP-positive perichondrial cells in homozygotic tibiae possessed a spindle-shaped cell contour and small cytoplasm, the extracellular matrix of which contained neither type I collagen nor calcifying matrix vesicles. In contrast, some perichondrial cells at the very middle part of tibiae became flattened. In the vicinity of these cells, a thin layer of type I collagen-based calcified matrix, containing osteopontin, bone sialoprotein, or osteocalcin, was observed. In the cartilage of mutant mice, we observed a hypoplasic zone of proliferative chondrocytes, the flattening of hypertrophic chondrocyte-like cells, and calcified chondrocytes which, while not degraded, did display a high level of cell function. Mononuclear osteoclastic cells were found in the perichondrium, near calcified chondrocytes, in mutant mice. Multinuclear osteoclasts possessing H+-ATPase and ruffled borders were also present, although only in limited numbers. Neither the development of ruffled borders nor intracellular polarization was complete. Because the majority of osteogenic cells in Cbfa1-deficient mice can neither form nor calcify the bone matrix, Cbfa1 principally plays essential roles in osteoblastic differentiation and bone matrix formation. Cbfa1 also affects both the proliferation and the differentiation of chondrocytes, whereas its absence prevents normal osteoclast formation and related functions.

Animals↗
PubMed1999

Effect of sperm immobilisation and demembranation on the oocyte activation rate in the mouse.

To analyse the effect of the state of the sperm plasma membrane on oocyte activation rate following intracytoplasmic sperm injection (ICSI), three types of human and mouse spermatozoa (intact, immobilised and Triton X-100 treated) were individually injected into mouse oocytes. At 30, 60 and 120 min after injection, maternal chromosomes and sperm nuclei within oocytes were examined. Following human sperm injection, the fastest and the most efficient oocyte activation and sperm head decondensation occurred when the spermatozoa were treated with Triton X-100. Intact spermatozoa were the least effective in activating oocytes. Thus, the rate of mouse oocyte activation following human sperm injection is greatly influenced by the state of the sperm plasma membrane during injection. When mouse spermatozoa were injected into mouse oocytes, the rates of oocyte activation and sperm head decondensation within activated oocytes were the same irrespective of the type of sperm treatment prior to injection. We witnessed that live human spermatozoa injected into moue oocytes often kept moving very actively within the ooplasm for more than 60 min, whereas motile mouse spermatozoa usually became immotile within 20 min after injection into the ooplasm. In 0.002% Triton X-100 solution, mouse spermatozoa are immobilised faster than human spermatozoa. These facts seem to suggest that human sperm plasma membranes are physically and biochemically more stable than those of mouse spermatozoa. Perhaps the physical and chemical properties of the sperm plasma membrane vary from species to species. For those species whose spermatozoa have 'stable' plasma membranes, prior removal or 'damage' of sperm plasma membranes would increase the success rate of ICSI.

Animals↗