Search PubMed⌕ Search

Biomedical subjects

A Fukuda

Publications and source records attributed to A Fukuda.

At least 127 records · Page 7Linked to original sources
PubMed1995

Ceruloplasmin concentration in human colostrum and mature milk.

The concentration of ceruloplasmin (CP) in human milk was obtained by measuring the increased absorbance of a solution containing apotransferrin and Fe2+ at 460 nm after adding the milk. The CP concentrations in colostrum and mature milk at less than 1 month after parturition were 4.45 +/- 1.23 mg and 4.09 mg +/- 1.47 mg/100 ml, respectively. In mature milk after more than one month, the CP concentration had decreased to 1.72 +/- 0.91 mg/100 ml.

Apoproteins↗
PubMed1995

Hypothalamic neurons are resistant to the intoxication with 3-nitropropionic acid that induces lesions in the striatum and hippocampus via the damage in the blood-brain barrier.

Modulation of the function of the blood-brain barrier (BBB) in the hypothalamus was investigated after the intoxication with 3-nitropropionic acid (3-NPA) that inhibits the succinate dehydrogenase. 3-NPA was administered to rats for three days. Following transcardial perfusion, brain sections were studied by immunohistochemistry. On the 2nd or 3rd day after 3-NPA, strong immunoreactions for blood-borne macromolecules, IgG, appeared in the striatum and hippocampus. Glial fibrillary acidic protein (GFAP) positive astroglias distributed heterogeneously, and induced nitric oxide synthase (iNOS) positive cells appeared around the vessels. A week later, bilateral lesions were detected in these areas. In the hypothalamus, there appeared a moderate immunoreaction for IgG, but no expression of iNOS. GFAP positive astroglias were rich especially around the vessels, and no loss in microtubule-associated protein 2 (MAP2) immunoreaction was detected, suggesting an intact BBB structure and no neuronal loss following 3-NPA intoxication. Data indicate that hypothalamic neurons are resistant to 3-NPA that induces specific lesions in the striatum and hippocampus via the damage in the BBB.

Animals↗
PubMed1994

Pathophysiological process after transient ischemia of the middle cerebral artery in the rat.

For the understanding of pathophysiology of the cerebral ischemia, we made a transient intraluminal occlusion of the middle cerebral artery in the rat and investigated the appearance of collapsed dark neurons and the extravasation of serum proteins using argyrophil III method and immunohistochemistry. In the acute stage (minutes to 3 days), dark neurons appeared in the lateral half of the ipsilateral striatum and adjacent cortex which formed the ischemic core of this model. Dark neurons also appeared in the ipsilateral reticular thalamic nucleus, hippocampus, and amygdala. The extravasation of serum proteins, albumin, leucocyte common antigen, immunoglobulin G, complement factor C3, as well as heat shock protein 70, was observed not only in the ischemic but sometimes also in the contralateral hemisphere. Among these, the expression of IgG and C3 was most prominent in the ischemic core. In the chronic stage (1 to 3 months), the ischemic core changed into the porencephaly, and the ventrobasal nucleus of the thalamus got also involved in the necrosis. A strong microgliosis was observed in the substantia nigra pars reticulata. Data suggest, that among many mechanisms that contribute to ischemic neuronal death, the activation of immune response, due to the damage of blood-brain barrier and the extravasation of serum proteins could promote the ischemic cell death in the brain.

Animals↗
PubMed1994

Platelet activating factor enhances the acrosome reaction, fertilization in vitro by subzonal sperm injection and resulting embryonic development in the rabbit.

This study was conducted to investigate the effect of platelet activating factor (PAF) on the acrosome reaction and fertilizing capacity of spermatozoa, and development of the resulting embryos in the rabbit. Rabbit spermatozoa were exposed to PAF, lyso-PAF, or high ionic strength medium (HIS) prior to subzonal sperm injection (SUZI) into 326 mature oocytes, or morphological assessment of the acrosome reaction. The rates of fertilization and blastocyst formation were compared among the three treatment groups. Acrosome reaction was assessed by fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA) staining and electron microscopy. PAF-treated spermatozoa fertilized the oocytes at a significantly higher rate (56.1%) than did lyso-PAF-(36.8%, P < 0.01) or HIS- (38.2%, P < 0.05) treated spermatozoa. The embryos produced by PAF-treated spermatozoa showed significantly higher blastocyst formation rates (34.0%) than lyso-PAF- (8.6%, P < 0.05) or HIS-(8.8%, P < 0.05) treated spermatozoa. FITC-PSA staining demonstrated a significantly higher incidence of acrosome reaction in PAF-treated spermatozoa (45.8%) than in lyso-PAF- (28.0%, P < 0.01) or HIS- (34.9%, P < 0.01) treated spermatozoa. Acrosome reaction of PAF-treated spermatozoa was also confirmed by electron microscopy. PAF treatment of spermatozoa enhances fertilizing capacity for SUZI possibly by augmenting the acrosome reaction. Enhanced embryonic development was also found in the oocytes fertilized by SUZI of PAF-treated spermatozoa.

Acrosome↗
PubMed1994

Neuronal damage following transient cerebral ischemia and its restoration by neural transplant.

The middle cerebral artery (mca) was intraluminally occluded for one hour prior to reperfusion in the rat. Neuronal damage as well as motor imbalance were assessed in both acute and chronic stages with or without neural transplant in the striatum. In acute stage, argyrophil III staining demonstrated "collapsed" dark neurons in the ipsilateral striatum, cortex, reticular thalamus, amygdala and sometimes in the hippocampus. They had shrunken somata and corkscrew-like dendrites. In accordance with the appearance of dark neurons, the immunoreactivity for calpain of endogenous inactive form decreased or disappeared in ischemic areas. In chronic stage, ischemic core area (striatum and cortex) got into porencephaly, and animals made rotations following methamphetamine injection. Neural transplant (fetal striatal cells) was made during 2 to 4 weeks after the ischemia. Once the transplant survived and grew in the striatum, the methamphetamine rotations were attenuated. Using mca ischemic model rats we report here pathophysiological processes that lead to neuronal damage and infarct. Neural transplants into these animals brought partial restoration in motor disturbance, offering a valuable information concerning therapeutic possibility.

Animals↗
PubMed1994

Reactivation of phototoxicity test for psoralens plus ultraviolet A by low-dose methotrexate.

Reactivation of a solar burn has been reported after administration of methotrexate for cancer and psoriasis patients. We report a case of psoriasis with a similar but delayed elicitation of phototoxic reaction by administration of low-dose methotrexate one month after psoralen and long-wave ultraviolet light (PUVA) treatment. The reactivation was seen in an already receding phototoxicity test area but not in a less phototoxic, noninterval PUVA treated area, suggesting that the reactivation by methotrexate is related with the severity of light-induced skin inflammation.

Aged↗
PubMed1994

[Nontraumatic acute subdural hematoma caused by the rupture of transdural anastomotic vessels in moyamoya disease].

A case of nontraumatic acute subdural hematoma caused by the rupture of transdural anastomotic vessels in a patient with Moyamoya disease is reported. The patient was a 55-year-old woman who was admitted to our hospital in a comatose state. A diagnosis of acute subdural hematoma associated with Moyamoya disease was made on the basis of CT and angiographic findings. No lesions suggestive of trauma, such as cerebral contusion, could be detected during surgery. Although total evacuation of the hematoma was performed, she developed the apallic syndrome and did not recover consciousness. Judging from the angiographic and operative findings, it appears that subarachnoid hemorrhage occurred first and stretched the transdural anastomotic vessels which supplied the collateral circulation. This led to tearing of some of the vessels, and their proximal ends were consequently exposed in the subdural space. The surgical treatment of acute subdural hematoma associated with Moyamoya disease requires the closest attention to avoid damage to the collateral circulation. Although we carefully arrested the bleeding without using a coagulator in order to spare the collateral vessels, the transdural anastomosis was no longer visible on postoperative angiograms. Our experience suggests that hematoma irrigation with trephination therapy, which may minimize the damage to the collateral circulation, may be the most appropriate treatment for acute subdural hematoma associated with Moyamoya disease. Furthermore, cerebral revascularization should be performed for the treatment of the circulatory disturbance intercepted by the hematoma itself or by operative manipulation.

Acute Disease↗
PubMed1993

Rare mutations of the Gs alpha subunit gene in human endocrine tumors. Mutation detection by polymerase chain reaction-primer-introduced restriction analysis.

BACKGROUND: The Gs alpha (Gs alpha) gene can be activated to the putative oncogene gsp by specific point mutations at codons 201 or 227. Such mutations have been reported in growth hormone (GH)-secreting pituitary adenomas and thyroid tumors. To clarify the role of Gs alpha gene in human endocrine tumors, 197 tumors were screened for point mutations at codons 201 or 227 of the Gs alpha gene. METHODS: Mutations were detected by primer-introduced restriction analysis (PIRA) of the polymerase chain reaction (PCR) product of genomic DNA. RESULTS: These Gs alpha mutations were present in 4 of 53 pituitary adenomas (4 of 43 GH-secreting adenomas; 1 of these 4 was a GH- and prolactin-secreting adenoma from a patient with familial multiple endocrine neoplasia Type 1), 4 of 66 thyroid tumors (4 of 30 papillary carcinomas), and 1 of 19 adrenocortical adenomas (1 of 6 aldosterone-secreting adenomas). In contrast, none of these Gs alpha mutations were detected in parathyroid tumors, endocrine pancreatic tumors, or pheochromocytomas. CONCLUSIONS: Gs alpha mutations at these two loci may play a role in the pathogenesis of a small population of GH-secreting pituitary adenomas, papillary thyroid carcinomas, and adrenocortical adenomas, but that they are not involved in the pathogenesis of other types of endocrine tumors.

Acromegaly↗
PubMed1993

Forskolin stimulates porcine sperm capacitation by increasing calcium uptake.

Using the fluorescent calcium indicator fura-2, forskolin was found to dose-dependently cause an immediate increase in the concentration of intracellular free calcium of porcine cauda epididymal sperm. This stimulatory effect of forskolin is due to the enhancement of Ca2+ uptake by the verapamil-sensitive transporter on the sperm plasma membrane and results in the promotion of the sperm capacitation and subsequent acrosome reaction.

Acrosome↗
PubMed1993

Differential ontogenesis of presynaptic and postsynaptic GABAB inhibition in rat somatosensory cortex.

1. The postnatal maturation of gamma-aminobutyric acid (GABA)B receptor-mediated presynaptic inhibition was studied in brain slices of rat somatosensory cortex maintained in vitro. Patchclamp techniques were used to record whole-cell inhibitory post-synaptic currents from layer II-III neurons in animals from postnatal days (P) 7-24. Monosynaptic inhibitory postsynaptic currents (IPSCs) were evoked after N-methyl-D-aspartate (NMDA) and non-NMDA type glutamate receptors had been blocked by D-amino-phosphonovaleric acid (D-AP5, 20 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM), respectively. These IPSCs were solely mediated by postsynaptic GABAA receptors because they were abolished by bicuculline (10 microM), reversed polarity near the chloride equilibrium potential, and were recorded with electrodes that contained Cs+ to block postsynaptic GABAB responses. 2. When pairs of stimuli separated by intervals of 0.1-10 s were used to evoke IPSCs, the second response was depressed, an effect that was maximal at 300 ms. Evoked IPSCs were also depressed by baclofen (10 microM). The paired pulse depression (PPD) of monosynaptic IPSCs was decreased or eliminated by 2-OH-saclofen (200 microM). These findings indicate that PPD of monosynaptic IPSCs was due to presynaptic GABAB receptor-mediated inhibition of GABA release. 3. There were no significant differences in the amounts of PPD in neurons from different age groups (P7-10, P12-17, P22-24) at any interstimulus interval tested (0.1-10 s).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Effect of aggressive haemoperfusion on the clinical course of patients with paraquat poisoning.

The effect of aggressive haemoperfusion; i.e. haemoperfusion of 10 h or more during the first 24 h after ingestion, on the clinical course of paraquat poisoning was studied. Among 40 patients admitted within 15 h after ingestion of paraquat with an SIPP of less than 100 (h x micrograms ml-1), 21 received aggressive haemoperfusion and 19 received conventional haemoperfusion; i.e. haemoperfusion of less than 10 h during the same period. Survival rates of patients with severity between an SIPP of 100 and Proudfoot's curve in the two groups were compared by the log-rank test. Aggressive haemoperfusion did not improve the outcome but did improve the survival rates; that is, the number of patients surviving at particular points in time (P < 0.05). The length of haemoperfusion for the aggressive haemoperfusion group was longer than that for the conventional group on the first day (P < 0.001), but the difference was insignificant during the following two days. Neither the time from ingestion to haemoperfusion, urine volume from the first to third day, nor initial plasma-paraquat concentrations and SIPP were significant between groups. These findings imply that aggressive haemoperfusion reduces the severity of paraquat poisoning and elongates survival time. We, therefore, propose that the efficacy of more aggressive haemoperfusion, such as the 'continuous haemoperfusion' proposed by Okonek et al., should be further studied.

Adolescent↗
PubMed1993

A comparative study of urinary xanthopterin and neopterin in liver diseases.

By adsorption to activated charcoal, various pteridine derivatives in human urine are oxidized to xanthopterin. Following this oxidation, xanthopterin in urine from healthy subjects and from patients with liver diseases was assayed by high performance liquid chromatography. The mean values for xanthopterin in healthy subjects were 532 +/- 116 mumol/mol creatinine (mean +/- SD) in males and 585 +/- 153 mumol/mol creatinine in females; the difference was statistically significant (p < 0.01). Xanthopterin concentrations in patients with liver disease were significantly higher than those in normal subjects. When compared with urinary neopterin, which is a marker of activated cell immunity, xanthopterin was significantly increased even in fatty liver disease. These findings suggest that increased concentrations of urinary xanthopterin in liver diseases reflect not only the status of activated cell-mediated immunity, but also injury to liver cells.

Adult↗
PubMed1993

Spectral sensitivity of monochromatic ERG c-wave of chicken under color adaptation.

The spectral sensitivity of the ERG c-wave was studied in the chicken under yellow or red light adaptation of various intensities, ie, 1, 3, 4 and 5 W/m2 at the corneal surface in the former, and 3, 4 and 5 W/m2 in the latter. The peak wavelength of the spectral sensitivity curve of the c-wave amplitude under both yellow and red light adaptations was 520 or 540 nm, being shorter as compared with the peak wavelength (560 nm) under white light adaptation (Fukuda, 1989). Under the yellow or red light adaptation the sensitivity of the c-wave was suppressed at a range of longer wavelength, suggesting a possible isolation of the blue and green cone-driven c-wave responses. The peak (520 or 540 nm) and the shoulder (580 nm) in the spectral sensitivity curves were presumed to be derived from the three cone systems.

Adaptation, Ocular↗
PubMed1992

Role of p53 mutations in endocrine tumorigenesis: mutation detection by polymerase chain reaction-single strand conformation polymorphism.

To elucidate the molecular basis for endocrine tumorigenesis, p53 mutations in human endocrine tumors were analyzed by using polymerase chain reaction-single strand conformation polymorphism. Exons 5 through 10 of the p53 gene were studied in genomic DNAs from 134 primary endocrine tumors and 6 human endocrine cancer-derived cell lines. Mutations were detected and identified in 4 endocrine tumors, including one parathyroid adenoma and three thyroid carcinoma cell lines. The sites of these mutations were in exons 5 (codon 151 and 152) and 7 (codon 248 and 255). In all of three tumor cell lines, but not in a parathyroid adenoma, the normal allele encoding the p53 gene was lost. However, p53 mutations were not found in any other endocrine tumors or cell lines. Based upon these results, we concluded that the p53 gene may play a role in the tumorigenesis of a limited number of parathyroid adenoma and thyroid cancers, and that the p53 mutation with an allelic loss of the p53 gene is an important factor in malignant tumorigenesis of the thyroid gland.

Base Sequence↗
PubMed1992

Changes in the nature of calcium transport systems on the porcine sperm plasma membrane during epididymal maturation.

Comparative studies of 45Ca(2+)-transport across the plasma membrane were performed using porcine caput, corpus and cauda epididymal sperm. The Ca(2+)-uptake is dependent on the presence of the substrates for respiration and is sensitive to verapamil. The Ca(2+)-efflux is mediated by both Na(+)-dependent and -independent systems. In the immature sperm in caput epididymis, Na(+)-independent efflux is predominant, but it is gradually replaced by Na(+)-dependent efflux during the epididymal transit. The net activity of Ca2+ accumulation into sperm increases with the epididymal maturation.

Animals↗
PubMed1992

Postnatal development of electrogenic sodium pump activity in rat hippocampal pyramidal neurons.

We assessed the development of electrogenic sodium pump (Na+ pump) activity in CA1 pyramidal neurons of rat hippocampal slices by studying the prolonged hyperpolarization which follows glutamate-induced depolarization (postglutamate hyperpolarization or PGH) at different postnatal ages. We also examined the development of membrane-bound enzyme in the hippocampal CA1 subfield with light microscopic immunocytochemistry and an antiserum against Na+,K(+)-ATPase. The PGH, which has previously been shown to be due to activation of an electrogenic Na+ pump in adult hippocampal CA1 neurons, was eliminated by strophanthidin, a Na+,K(+)-ATPase inhibitor, at all ages. It was unaffected by several potassium channel blockers, an intracellular calcium chelator, intracellular Cl- injection or tetrodotoxin (TTX) perfusion. The PGH thus appeared to be independent of K+ and Cl- conductances and produced by an electrogenic Na+ pump in adult and immature animals activated in large part by entry of Na+ through the glutamate receptor-channel complex. The size (integrated area) of the PGH was directly proportional to the area of preceding glutamate-induced depolarization (GD) and relatively voltage independent. Similar GDs could be elicited from postnatal day (P) 7 to P greater than or equal to 35, however, only very small PGHs were produced in neurons from P7-11 animals. A ratio of PGH area to GD area (PGH ratio) was calculated for each neuron and used to compare Na+ pump activity at different ages. There was a significant increase in the mean PGH ratio with age when P7-11, P21-25 and P35-39 groups were compared. Na+ pump activity estimated from the PGH ratio is very low in the first postnatal week but develops gradually over the first 5 weeks of life. Immunostaining for Na+,K(+)-ATPase in adult rat hippocampi revealed a punctate reaction product surrounding pyramidal cell bodies, whereas the staining was uniform along plasmalemma of dendrites in stratum radiatum and stratum oriens. By contrast, only minimum staining was present surrounding cell bodies and dendrites of P7 hippocampi and staining in stratum pyramidale was not punctate at this age. Na+,K(+)-ATPase activity estimated grossly from immunocytochemical staining is very low in the first postnatal week, increases during the first 5 weeks and develops a characteristic focal localization.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗