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Biomedical subjects

M Funahashi

Publications and source records attributed to M Funahashi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Regulation of hyaluronate metabolism by progesterone in cultured fibroblasts from the human uterine cervix.

The effects of progesterone, dehydroepiandrosterone sulfate and 17beta-estradiol on the synthesis and degradation of hyaluronate were investigated using human uterine cervix fibroblasts. The cells were incubated with [3H]glucosamine in the presence of the hormones and then [3H]hyaluronate was isolated from the medium. The changes in the radioactivity of [3H]hyaluronate showed that progesterone suppressed hyaluronate synthesis by 22% of the control levels, while dehydroepiandrosterone sulfate and 17beta-estradiol enhanced it by 22% and 12% of the control levels, respectively. Furthermore, progesterone induced degradation of high-molecular-weight [14C]hyaluronate into low-molecular-weight hyaluronate (Mr approximately 40000). These results suggest that in cultured fibroblasts from the human uterine cervix progesterone converts hyaluronate metabolism from the synthesis phase to the degradation phase.

Cells, Cultured↗
PubMed1997

Presubicular and parasubicular cortical neurons of the rat: electrophysiological and morphological properties.

Intracellular recordings and Neurobiotin-injection were used to examine the electrophysiology and morphology of presubicular and parasubicular cortical neurons in horizontal slices from rat brains. Evoked responses were obtained by stimulation of subicular and entorhinal cortices. Stellate cells were recorded in layers II and V of presubiculum and parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that did not reach past layer IV. Pyramidal cells were recorded in layers III and V of presubiculum and layers II and V of parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that could reach layer II. Electrophysiologically, stellate and pyramidal cells were similar to one another, regardless of cell layer, exhibiting repetitive single spiking in response to depolarizing current injection. No cells were found to burst in response to current injection. While there were subtle electrophysiological differences among the cell types, stellate cells were more similar to pyramidal cells from the same or adjacent layers than to other stellate cells from more distant layers. Similarly, pyramidal cells were electrophysiologically more similar to nearby stellate cells than to other distant pyramidal cells. Cells of all layers responded to subicular stimulation with a short latency (< 9 ms), excitatory postsynaptic potential. Superficial layer cells responded at short (< 9 ms), longer (10-20 ms) and very long latencies (> 20 ms) to stimulation of superficial layers of medial entorhinal cortex. Deep layer cells responded at short latencies (< 9 ms) to stimulation of deep layers of medial entorhinal cortex. Many cells responded to both subicular and entorhinal inputs. Both pyramidal and stellate cells in the deep layer of pre/parasubiculum could exhibit population bursting behavior in response to stimulation of subiculum or entorhinal cortex. The results define the cellular morphology and basic electrophysiology of presubicular and parasubicular neurons of the rat brain as a step toward understanding the physiology of the retrohippocampal cortices.

Action Potentials↗
PubMed1997

Exaggerated C-fiber activation prevents peripheral nerve injury-induced hyperinducibility of c-Fos in partially deafferented spinal dorsal horn.

Dorsal horn neurons chronically deafferented by peripheral nerve injuries acquire hypersensitivity to noxious input from outside the original receptive field. This study examines the effect of electrical nerve stimulation at the time of injury on such injury-induced hypersensitivity. The medial 3/8 of the dorsal horn laminae I/II around the junction of 4th and 5th lumbar segments (the tibial territory) was deafferented by transection of the ipsilateral tibial nerve in rats. At 2 days or 3 weeks postinjury, the hindpaw was injected with formalin to induce c-fos. At 2 days, neurons with induced c-Fos protein-like immunoreactivity (fos-neurons) were largely confined in the lateral 5/8 of laminae I/II (the peroneal and hip, thus P and H territory). At 3 weeks, fos-neurons significantly increased in the deafferented tibial territory. A similar increase was also noted in the P and H territory. Thus the dorsal horn neurons exhibited c-fos hyperinducibility, an indication of hypersensitivity. Electrical stimulation with a train of 150 shocks (10 V, 2 ms) of the proximal nerve stump immediately after transection prevented the c-fos hyperinducibility. The effect was greater with the stimulation frequency of 0.5 Hz than 0.1 Hz or 10 Hz. The stimulation had no effect on the c-fos inducibility at 2 days postinjury.

Animals↗
PubMed1997

Effect of 4-methylumbelliferone on cell-free synthesis of hyaluronic acid.

Human skin fibroblasts were cultured in the presence of 0.5 mM 4-methylumbelliferone for 12 h, and cell-free synthesis of hyaluronic acid was performed using membrane-rich fraction from the cells. The preincubation of the cells with 4-methylumbelliferone reduced hyaluronic acid synthesis to 15% of that of non-preincubated cells, although its chain length was not changed. On the other hand, without preincubation of the cells with 4-methylumbelliferone, hyaluronic acid synthesis was not changed even when 4-methylumbelliferone was added directly to the reaction mixture. These results suggest that 4-methylumbelliferone represses the expression of hyaluronic acid synthase on the cell surface.

Cell Membrane↗
PubMed1996

Are breaches in the glia limitans the primary cause of the micropolygyria in Fukuyama-type congenital muscular dystrophy (FCMD)? Pathological study of the cerebral cortex of an FCMD fetus.

A light and electron microscopic study of the brain of an 18-week fetus with a prenatal genetic diagnosis of Fukuyama-type congenital muscular dystrophy revealed a widespread mantle of abnormal neurogliomesenchymal tissue that covered a dysplastic cerebral cortex. In this area alone, the glia limitans that adjoined the abnormal mantle via one or two layers of basal lamina had frequent breaches, through which neuroglial elements extruded. In the most severely affected cortical region, which had only a rudimentary and fragmentary glia limitans, the majority of cortical neurons had migrated into the neurogliomesenchymal tissue. The massive overmigrated neurons still maintained a somewhat columnar arrangement, and the marked dysplasia abruptly shifted to a neurogliomesenchymal tissue-free normal cortical structure with an intact glia limitans, thus indicating essentially vertical overmigration of neurons without significant tangential migration of them. Together the above findings imply that breaches in the glia limitans may be the primary cause of the micropolygyria seen in this genetic disorder.

Cerebral Cortex↗
PubMed1996

[Epidemiology of pertussis and studies on culture positive pertussis cases in Japan].

The number of pertussis patients has decreased steadily in the late 1960s and was extremely small in early 1970s. During 1973-74 the first national survey on pertussis cases confirmed by culture was conducted, when whole cell pertussis vaccine was used. The study revealed that 33.3% of culture positive cases had 2-4 doses of DT combined with whole cell pertussis vaccine. Acellular pertussis vaccine was introduced in 1981 and for the last several years the number of pertussis patients became low for the second time. During 1988-92 exactly the same study was conducted as the previous one. Among 2501 pertussis cases diagnosed clinically 403 were culture positive. Most of the patients were below 1 year of age. Most of the patients were below 1 year of age. Clinical symptoms of those infants were more serious than those of older children. Only 7 out of 403 (1.8%) had a history of 2-4 doses of DT combined with acellular pertussis vaccine. This proved that the acellular pertussis vaccine is by far more effective than the whole cell pertussis vaccine. Serotypes of 377 Bordetella pertussis were identified and 370/377 (98.1%) were serotype 1-3 group.

Adolescent↗
PubMed1995

Glucose-responsive neurons in the brainstem.

AREA POSTREMA: The influence on feeding behavior caused by ablation of the area postrema (AP) in rodents indicates the participation of this structure in the control of ingestion. Two types of glucose responsive neurons were identified in the AP: one is characterized by increasing the discharge rate in response to glucose (glucoreceptor type) and the other by decreasing the discharge rates in response to glucose (glucose sensitive type). These glucose responsive neurons may participate in glycemic homeostasis. NUCLEUS OF SOLITARY TRACT: The glucose responsive neurons exist within the caudal portion of nucleus of the solitary tract (NTS), a relay station in visceral afferents. Two types similar to the AP were also recognized. It is confirmed that hepatic glucose sensitive afferents terminate on some of the glucose sensitive neurons. This convergence may serve as a fail-safe mechanism. In addition, the NTS involving complex neural networks of excitatory and inhibitory interneurons may be concerned with integration of glycemic information. DORSAL MOTOR NUCLEUS OF VAGUS: Some neurons within the dorsal motor nucleus of the vagus (DMV) were identified as the glucose responsive ones. Both types were also recognized. It is confirmed by antidromic activation that these glucose responsive DMV neurons send their axons toward the gastric or coeliac branch that innervates either the stomach, intestine or pancreas. Some of the DMV neurons may subserve an enteroceptor function by themselves. They may also play a role in the brainstem neural control of glycemic homeostasis as the fail-safe mechanism.

Animals↗
PubMed1995

Tissue fibronectin is an endogenous ligand for galectin-1.

A 14K beta-galactoside-binding lectin (galectin-1) is present in many animal tissues. In a search for endogenous ligands, we surveyed galectin-1-binding proteins in human placenta. Extract of human placenta with 2 M urea was applied to a Sepharose 4B column conjugated with galectin-1 purified from frog (Rana catesbeiana) eggs. Two major proteins eluted with 100 mM lactose from the column-bound fraction showed apparent molecular masses of 220 and 180 kDa on SDS-PAGE under reducing conditions. Western blotting analysis using monoclonal antibodies indicated that these proteins were fibronectin and laminin, respectively. Most placental and amniotic fibronectins bound strongly to the column, whereas almost all plasma fibronectin passed through the column. The galectin-1, fibronectin and laminin were immunohistochemically shown to be co-localized in the extracellular matrix of placental tissue. In a cell attachment assay, rhabdosarcoma cells adhered to a plate coated with placental fibronectin, even in the presence of GRGDS peptide, if galectin-1 were also present. This adhesive effect of galectin-1 was inhibited by lactose. These results indicate that tissue fibronectin, as well as laminin, serve as endogenous ligands for galectin-1, suggesting that galectin-1 may play a role in assembly of the extracellular matrix, or in the control of cell adhesion based on lectin-extracellular matrix interaction.

Animals↗
PubMed1993

Glucose-responsive neurons exist within the area postrema of the rat: in vitro study on the isolated slice preparation.

Responses to glucose of spontaneously active neurons were investigated by extracellular recording in the rat area postrema slice preparations (in vitro). Among 67 spontaneously active neurons, 16 neurons displayed a marked increase or decrease in discharge rate in response to increases or decreases of the glucose concentration in perfusate. These results confirm the existence of glucose-responsive neurons within the area postrema suggested in prior in vivo experiments. Response to CCK or dopamine was also examined on the isolated area postrema slices. The neuron that showed a marked increase in discharge rate responding to glucose elicited a marked increase of discharge rate in response to 2.1 microM CCK, suggesting that glucose and CCK affect the same neurons. Some neurons showed a marked increase or decrease in the discharge rate in response to 20 microM dopamine, but these neurons showed neither response to CCK nor to glucose. It is likely that different neuronal networks in the area postrema contribute to control of ingestion and to initiation of nausea.

Animals↗
PubMed1993

Comparing the cell population on different intraocular lens materials in one eye.

We developed a method to evaluate cell adherence to different intraocular lens (IOL) materials in one eye in which we coated one half of the anterior surface of a poly(methyl methacrylate) (PMMA) IOL with poly(dimethyl siloxane), a silicone material. The lenses were implanted in the anterior chamber of rabbit eyes without lens extraction. Postoperative cellular reaction on the IOL surfaces was studied by specular microscopy. The IOLs were fixed in situ, removed from the eyes, and stained with hematoxylin-eosin so we could evaluate the cell population on the silicone and PMMA surface. Fewer cells were scattered on the silicone surface than on the PMMA surface. This method excludes surgical effects and allows a comparison of various IOL materials in the same eye.

Animals↗
PubMed1992

[A case of cardiac arrest encephalopathy in athetotic cerebral palsy].

A 25-year-old woman with cerebral palsy of spastic quadriplegia and athetosis showed typical cardiac arrest encephalopathy on neuropathology. The etiology of cerebral palsy was perinatal origin including prematurity, asphyxia and hyperbilirubinemia. Ventricular premature beats had developed since about 20 years of age. Muscle tone also increased with aging and symptoms of vago-vagal reflex were occasionally observed after eating. At 25 years, cardiac arrest occurred and cardiopulmonary resucitation was done immediately. She remained unconscious with absent corneal reflex and irregular respiration. EEG or auditory brain stem response showed flat activity. She died of respiratory failure 53 days after the episode of cardiac arrest. Neuropathology showed bilaterally symmetrical necrosis in the superior colliculi, gracilis nuclei, cuneate nuclei and spinotrigeminal nuclei accompanied with severe necrosis in the cerebrum and cerebellum. These findings in this adult case of total asphyxia were compatible with those observed in total plus partial asphyxia in the neonates. This discrepancy may be due to difference in cerebral maturity. Children or young adults with athetotic type cerebral palsy have a high risk of sudden death. Sudden cardiac arrest seems to play an important role in sudden death of these patients.

Adult↗
PubMed1992

Encainide-induced diabetes: analysis of islet cell function.

OBJECTIVE: The purpose of this study was to gain insight into the mechanisms responsible for encainide-induced diabetes. Specifically, we sought to determine if absolute insulinopenia was present or whether encainide-induced diabetes was metabolically more like type II than type I diabetes. RESEARCH DESIGN AND METHODS: Islet function was assessed in a 65 year old white male with encainide-induced diabetes. After 6 months of encainide treatment and 2 months duration of diabetes, C-peptide, glucagon, and glucose levels were measured at baseline and at 30 minute intervals for 120 minutes following an oral mixed meal. These measurements allowed assessment of islet beta and alpha cell function in comparison to control data from our laboratory. RESULTS: In this patient with encainide-induced diabetes, basal and peak C-peptide concentrations were similar to controls although peak C-peptide occurred substantially later than in controls. At peak glucose, the patient's C-peptide/glucose ratio was low indicating relative (but not absolute) insulinopenia. At baseline, glucagon was relatively depressed. Following Sustacal, there was an increase in glucagon of 100% over baseline compared to a mean glucagon rise in controls of only 8%. There was no serological evidence for autoimmune diabetes as islet cell autoantibodies were absent. CONCLUSIONS: Similar to other forms of diabetes, encainide-induced diabetes is a bihormonal disorder. The metabolic pattern was more like type II than type I diabetes with C-peptide secretion in the normal range, yet persistent hyperglycemia that suggests relative insulinopenia and concurrent insulin resistance.

Aged↗
PubMed1990

Potentiating effect of morphine upon d-methamphetamine-induced hyperthermia in mice. Effects of naloxone and haloperidol.

We have examined changes in rectal temperature of mice after subcutaneous administrations of d-methamphetamine alone or methamphetamine plus morphine. Methamphetamine 5 mg/kg produced slight hyperthermia, while simultaneous administration of morphine (25-100 mg/kg), which alone produces hypothermia, potentiated markedly the increase in body temperature by methamphetamine. Methamphetamine showed a hyperthermic effect in a dose-dependent manner in the presence of morphine. The hyperthermia due to methamphetamine plus morphine was avoided by pretreatment with 10 mg/kg naloxone. When animals were pretreated with 2.5 mg/kg haloperidol, hyperthermia due to methamphetamine alone was completely abolished, while that due to methamphetamine plus morphine was still observed. These results showed that dopamine may be implicated in methamphetamine hyperthermia and a haloperidol-nonsensitive mechanism may be involved in the methamphetamine-morphine hyperthermia.

Animals↗
PubMed1990

Gastric lesions in rats fed salted food materials commonly eaten by Japanese.

A high intake of salted food is thought to be related to the high incidence of stomach cancer in Japan. In the present study, female F344 rats were divided into four groups. They were fed a nutritionally deficient purified diet (Group 1) and standard purified diet (Group 3) for 113 weeks and the same diets supplemented with salted cuttlefish guts, broiled, salted, dried sardines, pickled radish, and soy sauce (Groups 2 and 4). The incidence of papillomas and ulcers of the forestomach was highest in Group 4, which was given the standard diet supplemented with the salty food materials (p less than 0.05). These results suggest the importance of salted food as a suspicious causal factor in human stomach cancer in Japan.

Animals↗
PubMed1990

[Sudden death of alcohol withdrawal syndrome--report of a case].

A 50-year-old driver was arrested in a drunken stupor while he was driving a track. He suddenly died after five days of the arrest in a jail. As time went by, various symptoms of alcohol withdrawal appeared. He was in the state of delirium treatments for about a day before he died. Gross and microscopical examination revealed fibrosis and fatty degeneration of liver and heart lesions representing chronic and acute ischemia. We discussed the cause and the mechanism of the death in the case and reviewed those in the previous observations.

Alcohol Withdrawal Delirium↗