Biomedical subjects

M Takase

Publications and source records attributed to M Takase.

At least 73 records · Page 4Linked to original sources

PubMed1997

Extracellular fibrillar structure of latent TGF beta binding protein-1: role in TGF beta-dependent endothelial-mesenchymal transformation during endocardial cushion tissue formation in mouse embryonic heart.

Transforming growth factor-beta (TGF beta) is a dimeric peptide growth factor which regulates cellular differentiation and proliferation during development. Most cells secrete TGF beta as a large latent TGF beta complex containing mature TGF beta, latency associated peptide, and latent TGF beta-binding protein (LTBP)-1. The biological role of LTBP-1 in development remains unclear. Using a polyclonal antiserum specific for LTBP-1 (Ab39) and three-dimensional collagen gel culture assay of embryonic heart, we examined the tissue distribution of LTBP-1 and its functional role during the formation of endocardial cushion tissue in the mouse embryonic heart. Mature TGF beta protein was required at the onset of the endothelial-mesenchymal transformation to initiate endocardial cushion tissue formation. Double antibody staining showed that LTBP-1 colocalized with TGF beta 1 as an extracellular fibrillar structure surrounding the endocardial cushion mesenchymal cells. Immunogold electronmicroscopy showed that LTBP-1 localized to 40-100 nm extracellular fibrillar structure and 5-10-nm microfibrils. The anti-LTBP-1 antiserum (Ab39) inhibited the endothelial-mesenchymal transformation in atrio-ventricular endocardial cells cocultured with associated myocardium on a three-dimensional collagen gel lattice. This inhibitory effect was reversed by administration of mature TGF beta proteins in culture. These results suggest that LTBP-1 exists as an extracellular fibrillar structure and plays a role in the storage of TGF beta as a large latent TGF beta complex.

Animals↗

PubMed1997

Effects of spinal cord ischemia on the refractory period of descending spinal cord evoked potential.

The recovery cycle, following the conduction of action potentials along a nerve fiber, consists of the absolute refractory period (ARP), the relative refractory period (RRP) and the supernormal period (SNP). The recovery cycle of the descending conductive spinal cord evoked potential (SCEP) was shown during normal state, ischemia and after ischemia using paired stimuli in cats. During ischemia the refractory period revealed a trend towards increment. Five minutes after reperfusion the refractory period decreased transiently compared with the normal level and within 30 min the refractory period returned to the normal level. The recovery curve of the 2nd potential showed different pattern compared with that of the 1st potential. Moreover, during ischemia, firstly the 3rd potential and secondly the 2nd potential of the SCEP elicited by the 2nd stimulus were disturbed. These results demonstrated that there is increased excitability of the spinal cord to the second stimulus after a brief period of ischemia, and that the 2nd and 3rd potentials are evoked synaptically and easily disturbed during ischemia. Measuring the SCEP elicited by paired stimuli or constructing the recovery curve of the SCEP is useful for the electrophysiological assessment of spinal cord function.

Action Potentials↗

PubMed1997

Transcranial magnetic stimulation-induced changes in EEG and responses recorded from the scalp of healthy humans.

We determined the changes and responses in the electroencephalogram (EEG) induced by transcranial magnetic stimulation (TMS) of the scalp of five healthy men. The center of a circular coil was positioned at the vertex, and 80 stimulations were administered clockwise with the maximum output of electric current. To reduce stimulus artifacts, we created a circuit that blocked the input for 150 ms after stimulation. EEGs were recorded from F3,4, C3,4, P3,4, and T3,4. The following results were obtained: (1) slowing of the EEG was observed immediately (150 m) after each stimulation. The incidence of changes ranged from 25-80%; their duration ranged from 200-600 ms. (2). Electroencephalographic responses in the averaged form appeared as gentle positive waves. In some subjects and leads, 1 to 3 negative peaks were fused. The methods used in the present study may be useful in evaluating the sensitivity to TMS of patients with stroke and other types of brain injury.

Adult↗

PubMed1997

Comparison of catalase in diploid and haploid Rana rugosa using heat and chemical inactivation techniques.

The present study examines differences in the hydrogen peroxide (H2O2) detoxifying enzyme, catalase, found in the tails and livers of diploid and haploid Rana rugosa. Investigative techniques include measurement of catalase activity and tests for temperature stability and chemical inhibition. Catalase from the tails of pre-climactic (stage XXIII) haploids was found to be over three times as H2O2 destructive as catalase from similar tails of diploids. Catalase from the livers of newly metamorphosed (stage XXV) froglets, on the other hand, displayed only one third the activity seen in diploid livers. The catalase in haploid tail and liver proved to be more heat resistant, retaining 40-60% of its original activity after 5 min of treatment at 55 degrees C, whereas diploid catalase was totally inactivated under the same conditions. Haploid and diploid catalase also responded differently to inhibition using urea and aminotriazole. These differences suggest that haploid catalase has diverged from normal diploid catalase through molecular modification, resulting in abnormal systems for H2O2 metabolism, which in turn are thought to be responsible for organ dysfunction and early death seen in haploid individuals.

Amitrole↗

PubMed1997

Fundamental electrophysiologic investigation of spinal cord: refractory period of feline conductive spinal cord evoked potential.

Refractory periods and recovery curves have been used to investigate the physiologic importance and disturbance of peripheral nerves, but the refractory periods of the central nervous system (CNS) have seldom been investigated. We estimated the refractory periods and the recovery curves of the ascending and descending conductive spinal cord evoked potentials (SCEP) in cats. The absolute refractory period of the first and second potentials of both the ascending and descending SCEP was approximately 0.4-0.5 ms. The amplitudes of the first potentials of the ascending and descending SCEP elicited by test stimuli exhibited significant differences, but their latencies did not differ significantly except at the interstimulus interval (ISI) of 1.5 ms, which implies that the same type of fibers was stimulated in the first potentials of the ascending and descending SCEP. The second potential of the descending SCEP elicited by test stimulus showed > 100% amplitude and a maximal recovery of 200% when the ISI was 3.0 ms. The third potential was produced in the test response more easily when a lower vertebral level (L4) was used as the recording site and the ISI was between 1.0 and 4.0 ms. We consider these phenomena to be the result of elimination of the synaptic inhibitory influence by the conditioning stimulus of the paired stimuli for the descending SCEP.

Action Potentials↗

PubMed1997

Effect of hypoxia on amniotic fluid erythropoietin levels in fetal rats.

Erythropoietin (EPO) levels in amniotic fluid and serum were measured in hypoxic (fraction of inspired oxygen, FiO2, 0.09) and posthypoxic (following a 24-hour period of hypoxia, FiO2 0.09) fetal rats on day 21 of gestation. Each of the study groups comprised 12-20 fetuses. Each of the control groups consisted of 21 or 22 fetuses. Fetal serum EPO levels at 3, 6, 9, 12, and 24 h of hypoxia were significantly higher than the control level. Amniotic fluid EPO levels at 9, 12, and 24 h of hypoxia were also significantly increased compared to the control level. Fetal serum EPO levels returned to baseline during the 12- to 48-hour period after hypoxia. During the 0- to 48-hour posthypoxic period, amniotic fluid EPO levels were significantly higher than the control level. These data demonstrate that rates of appearance and turnover of amniotic fluid EPO are different from those of fetal serum EPO.

Amniotic Fluid↗

PubMed1997

Electrophysiological investigation of hemifacial spasm after microvascular decompression: F waves of the facial muscles, blink reflexes, and abnormal muscle responses.

In patients with hemifacial spasm, it has been said that the spasm is due to cross compression of the facial nerve by a blood vessel and that microvascular decompression (MVD) of the facial nerve is an effective treatment. The F waves, which result from backfiring of antidromically activated motor neurons of the facial motor nucleus, are indices of the excitability of the facial motor nucleus and are enhanced in patients with hemifacial spasm. Measuring blink reflexes and abnormal muscle responses (lateral spread), a characteristic sign of hemifacial spasm, has been used to investigate the mechanism of hemifacial spasm pathophysiologically. Thus the authors measured F waves of the facial muscle, blink reflexes, and abnormal muscle responses before and after MVD in patients suffering from hemifacial spasm to investigate the excitability of the facial motor nucleus and the course of the cure of hemifacial spasm after MVD. The authors obtained facial nerve-evoked electromyograms in 20 patients with hemifacial spasm before and after the MVD procedure. On the spasm side, the F waves and blink reflexes were enhanced preoperatively compared to those on the normal side and abnormal muscle responses were recorded in all patients. In 12 patients whose hemifacial spasm had not disappeared completely for 5.1 +/- 1.7 (mean +/- standard error) months following the MVD procedure, F waves were still enhanced significantly and abnormal muscle responses were still recordable, albeit at lower amplitude. Within 1 month after the hemifacial spasm had disappeared completely. F waves were still significantly enhanced in 17 patients and abnormal muscle responses were recorded in seven of 15 patients. Subsequently, the enhanced F waves and abnormal muscle responses disappeared completely. The authors' study supports the hypothesis that the cause of hemifacial spasm is hyperexcitability of the facial motor nucleus and suggests that additional surgery should not be performed for at least 2 years after MVD, because that period is necessary for the disappearance of the hyperexcitability of the facial motor nucleus.

Adult↗

PubMed1997

A histopathologic study of localized portal hypertension as a consequence of chronic pancreatitis.

OBJECTIVE: To evaluate the mechanism of localized portal hypertension associated with stenosis or obstruction of the splenic vein in chronic alcoholic pancreatitis. DESIGN: Surgical and autopsy specimens from 12 patients with clinically diagnosed chronic alcoholic pancreatitis were examined histopathologically. Autopsy specimens of 10 normal pancreases served as control tissues. RESULTS: In tissues from 11 of the 12 patients with chronic-alcoholic pancreatitis, fibrosis in the pancreatic parenchyma continuously extended to the wall of the splenic vein; organized thrombus formation with recanalization was found in five patients, phlebosclerosis in four, and no changes were found in two. In two of the five patients with organized thrombus formation in the splenic vein, localized portal hypertension had been clinically diagnosed because of splenomegaly and varicose veins in the fundus of the stomach, but it was not accompanied by liver cirrhosis. In the control tissues, fibrosis was not observed in the peripancreatic tissue or the area surrounding the wall of the splenic vein. CONCLUSION: We regard localized portal hypertension due to stenosis or obstruction of the splenic vein as one of the consequences of peripancreatic fibrosis in chronic alcoholic pancreatitis.

Adult↗

PubMed1996

The neural origin generating early cortical components of SEP: topographical analysis using temporal-second-order-differentiation of cortical SEPs.

In order to identify dipole generators of the N20/P20 and P25, we employed second-order-differentiation in the temporal dimension (temporal-second-order-differentiation; TSOD) with delta t = 2 msec. The rate of variation in the voltage of cortical SEPs calculated by TSOD identified responses of each dipole, reflecting the density of neuronal firing. On topographic analysis, the distributions of N20/P20 and P25 conformed to the shape of gyrus better in the TSOD maps than in the isovoltage maps. The TSOD maps indicated that N20 and P25 were post-central components and that P20 was a pre-central one. Therefore, we concluded that the two dipoles generating N20/P20 and P25 were located in the posterior wall of the central sulcus (area 3b) and the crown (areas 1 and 2) of the post-central gyrus, respectively.

Brain Mapping↗

PubMed1996

Electrophysiological investigation of hemifacial spasm: F-waves of the facial muscles.

In patients with hemifacial spasm (HFS), the spasm is due to cross-compression of the facial nerve by a blood vessel. There are currently two hypotheses for the mechanism of HFS: 1) the spasm is caused by ephaptic transmission and an increase in excitability at the site of compression; and 2) the spasm is caused by hyperexcitability in the facial nerve nucleus. In peripheral nerves, F-waves, which result from the backfiring of antidromically activated anterior horn cells, have been proposed as indices of proximal motoneuron conduction and anterior horn cell excitability. Enhancement of the F-waves indicates increased anterior horn cell excitability. We have therefore measured F-waves in the facial muscle of HFS patients in order to investigate the excitability of the facial nerve nucleus. The authors obtained facial nerve evoked responses from 20 HFS patients before microvascular decompression (MVD), 10 HFS patients after MVD and 10 healthy controls. The F-waves, obtained with surface electrodes from the mentalis muscle, were the second response after the M-wave. On the patient's spasm side, the F-wave duration, F/M amplitude ratio and frequency of F-wave appearance significantly increased compared with those of the normal side or healthy controls; minimum latency and chronodispersion did not significantly differ between these groups. In patients whose spasm disappeared completely following MVD, the abnormal muscle response (lateral spread), which is a characteristic sign of HFS, and the enhancement of the F-wave eventually also disappeared. Because of the correlation between HFS and F-waves, the authors' study supports the hypothesis that the cause of HFS is hyperexcitability of the facial motonucleus.

Adult↗

PubMed1996

Stent endoprosthesis for obstructing colorectal cancers.

PURPOSE: Purpose of this study was to assess stent endoprosthesis for colorectal cancer (SECC) as an adjuvant to operative preparation in patients with obstructing colorectal cancers. METHODS: A self-expanding stainless steel stent was inserted in 15 patients with obstructing colorectal cancers under colonoscopic observation and fluoroscopic control. Following successful SECC, the colon was mechanically prepared using polyethylene glycol. Definitive surgical treatment then was undertaken. RESULTS: All 12 patients in whom the stent had been successfully placed recovered intestinal transit and tolerated mechanical preparation. A satisfactory preparation was confirmed during the operation. Two perforations and one dislocation were encountered. CONCLUSION: SECC is a new method for operative preparation of patients with obstructing colorectal cancers, which may reduce morbidity and mortality associated with this difficult problem.

Aged↗

PubMed1996

Abnormal muscle response (lateral spread) and F-wave in patients with hemifacial spasm.

In patients with hemifacial spasm (HFS) the spasm is due to cross compression of the facial nerve by a blood vessel and microvascular decompression (MVD) has proved to be a successful treatment. Abnormal muscle response (AMR), which can be elicited by one facial nerve branch stimulation in muscles innervated by other branches of the facial nerve, is specific for patients with HFS, and the AMR consists of a constant response occurring about 10 ms after stimulus and an afterdischarge with long duration (variable response, autoexcitation). The F-wave in facial muscles is a small recurrent discharge that antidromically propagates to the facial motonucleus and returns orthodromically down the same axon. We measured the AMRs and F-waves of facial muscles in HFS patients in order to investigate the relationship of both potentials and the origin of the AMRs. We obtained facial nerve evoked electromyograms from 10 HFS patients. The afterdischarges of the AMRs and the enhanced F-waves were always elicited at the same time by marginal mandibular branch stimulation of the facial nerve. There was a linear correlation between the duration of these two potentials in each case. Between the duration of the afterdischarge of the AMRs elicited in the mentalis muscles by the zygomatic branch stimulation of the facial nerve and that of the F-waves in the mentalis muscles, there was also a linear correlation in 10 cases. These results suggest that the F-wave and the afterdischarge have the same origin and that the AMR is an exaggerated F-wave.

Adult↗

PubMed1996

Effect of repetitive stimulation on lateral spreads and F-waves in hemifacial spasm.

The lateral spread (LS) response, which can be elicited in muscles innervated by other branches of the facial nerve, is electromyographycally specific for patients with hemifacial spasm (HFS), occurring about 10 ms after stimulus. The F-wave in facial muscles, which is a late response that antidromicaly propagates to the facial motonucleus and returns orthodromicaly down the same axon, revealed a trend toward enhancement in patients with HFS. The LSs were facilitated by repetitive stimulation during the microvascular decompression (MVD) operation, which has proved to be a successful treatment, and the F-waves were also facilitated by repetitive stimulation on the spasm side more than on the normal side. Greater facilitation of these responses was in direct proportion to higher stimulation rates and greater numbers of stimulations. The repetitive stimulation of the facial nerve may result in activation of the motoneuron pool and in the lowering of the threshold of somatic membranes. These results support the hypothesis that hemifacial spasm is caused by hyperexcitability of the facial motonucleus, which is increased by antidromic repetitive stimulation.

Electric Stimulation↗

PubMed1996

Strength-duration curve of conductive spinal cord evoked potentials in cats.

Strength-duration curves of the ascending and descending conductive spinal cord potentials (SCEPs) in cats were obtained using constant current stimuli. For the formulation of numeric indices of excitability, the rheobase is defined as the minimal current strength below which response cannot occur even if the current continues, and the chronaxie is defined as the minimal duration of a current required to evoke the potential at twice the rheobase strength. The chronaxies and rheobases were calculated from the constructed strength-duration curves. The purpose of this study is to produce strength-duration curves and to evaluate the utility of chronaxies and rheobases for SCEPs. This study showed the following results: (1) there was a hyperbolic relationship between stimulus strength and stimulus duration at threshold values, similar to that seen in peripheral nerves; (2) the ascending and descending tracts of SCEP were mediated through the same pathway (based on the similar chronaxies and rheobases); (3) following spinal cord compression the chronaxie and rheobase increased significantly (P < 0.05), which is similar to peripheral nerve disturbance. However, the rheobase decreased significantly following slight spinal cord compression (P < 0.05) and systemic cooling (P < 0.01), and the strength-duration curve shifted showing a tendency towards decrease of the galvanic threshold, therefore, amplitude augmentation with slight compression and with decrease in temperature seems to contribute to the reduction of the threshold. The strength-duration curve, the chronaxie and the rheobase may be useful in assessing spinal cord function.

Animals↗

PubMed1996

F-wave in patients with hemifacial spasm: observations during microvascular decompression operations.

In patients with hemifacial spasm (HFS), the spasm is due to cross compression of the facial nerve by a blood vessel. There are currently two hypotheses how the cross compression can cause HFS: 1. the spasm is caused by ephaptic transmission and hyperexcitability at the site of compression; and 2. the spasm is caused by hyperexcitability in the facial motonucleus. In peripheral nerves, F-waves, which result from the backfiring of antidromically activated anterior horn cells, have been proposed as indices of anterior horn cell excitability. Enhancement of the F-waves in facial muscles also indicates increased excitability of the facial motonucleus. On the other hand, abnormal muscle response (AMR), which can be elicited by stimulating one branch of the facial nerve and recording electromyographically from muscles innervated by other branches of the facial nerve, is specific for patients with HFS. We have therefore measured the AMRs and the F-waves in the facial muscle of HFS patients under anesthesia in order to investigate the excitability of the facial motonucleus. We obtained facial nerve evoked electromyograms from 14 HFS patients during microvascular decompression (MVD) operation. The F-waves, obtained with surface electrodes from the mentalis muscle, were defined as the second response after the M-wave. The F-waves in facial muscles cannot usually be elicited during surgical anesthesia using inhalation anesthetics. However, the F-waves were elicited on the spasm side in 10 out of 14 patients with HFS and the F-waves disappeared after MVD under anesthesia, as the early responses (R1) of the blink reflex were elicited on the spasm side before MVD under anesthesia. The F-waves elicited during anesthesia were suppressed significantly, compared with those before MVD. These results suggest that excitability in facial motonucleus increased on the spasm side.

Electric Stimulation↗

PubMed1996

Histopathologic study of coexistent pathologic states in pancreatic fibrosis in patients with chronic alcohol abuse: two distinct pathologic fibrosis entities with different mechanisms.

The distribution and clinicopathologic features of pancreatic fibrosis were studied histopathologically in 137 autopsy cases of chronic alcohol abuse. Fibrosis was observed in 90 of the cases and was classified as perilobular sclerosis (PS) and intralobular sclerosis (IS). Fibrosis of the PS type was irregular and sometimes patchy and extended into the intralobular area in advanced cases. In some advanced cases, complete replacement of the pancreatic tissue by extensive fibrosis was seen. Fibrosis of the IS type was uniformly distributed. The tissues in some cases showed prominently periacinar fibrosis. In these cases, the pancreatic parenchyma had not been completely replaced by extensive fibrosis. Clinicopathologic comparisons revealed the following results: accompanying liver cirrhosis was greater in the IS than in the PS of fibrosis. However, a higher frequency of protein plugs, pancreatic stones, extensive fibrosis replacement, peripancreatic fibrosis, splenic vein involvement, choledochus involvement, pseudocyst, and ductal hyperplasia was found in the PS type compared to the IS type. In conclusion, the findings on the perilobular and intralobular distribution of fibrosis and differences in various components or accompanying diseases in pancreatic fibrosis suggest that this entity shows two distinct pathologic patterns with differing mechanisms.

Adult↗

PubMed1996

Effects of lactoferrin and lactoferricin on the release of interleukin 8 from human polymorphonuclear leukocytes.

Human or bovine lactoferrin (LF) and lactoferricin (LFcin), a peptide derived from the N-terminal region of LF, each have the ability to stimulate the release of neutrophil-activating polypeptide interleukin 8 (IL-8) from human polymorphonuclear leukocytes (neutrophils, PMNs). This finding suggests that LF and LFcin may both function as immunomediators for activating the host defense system. A basic peptide, protamine, exerted the same effect as that of LF and LFcin, suggesting the importance of the basic nature of LF and LFcin in acting as an inducer of IL-8 release from PMNs.

Amino Acid Sequence↗

PubMed1996

Oral administration of bovine lactoferrin for treatment of intractable stomatitis in feline immunodeficiency virus (FIV)-positive and FIV-negative cats.

OBJECTIVE: To study the effects of oral administration of bovine lactoferrin (LF) on intractable stomatitis in feline immunodeficiency virus (FIV)-positive and FIV-negative cats, and phagocytosis of neutrophils in healthy and ill cats, simultaneously. ANIMALS: 7 ill cats with diagnosis of intractable stomatitis (4 FIV positive and 3 FIV negative) and 7 healthy, FIV-negative cats. PROCEDURE: LF (40 mg/kg ot body weight) was applied topically to the oral mucosa of cats with intractable stomatitis daily for 14 days and improvement of clinical signs of disease (pain-related response, salivation, appetite, and oral inflammation), expressed by scoring from 1 to 4, were evaluated. Assay of neutrophil phagocytosis was examined before and 2 weeks after starting LF treatment, using nonopsonized hydrophilic polymer particles (2 microns). RESULTS: Oral administration of LF improved intractable stomatitis in all 4 respects. Phagocytic activity of neutrophils increased after LF treatment. This effect was observed in healthy and ill (FIV positive and FIV negative) cats. CONCLUSION AND CLINICAL RELEVANCE: Oral administration of LF improved intractable stomatitis and concurrently enhanced the host defense system. Topical application of LF to oral mucous membrane is useful as a treatment for intractable stomatitis even in FIV-positive cats.

Administration, Oral↗