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Biomedical subjects

T Akaishi

Publications and source records attributed to T Akaishi.

At least 19 recordsLinked to original sources

Morphine augments excitatory synaptic transmission in the dentate gyrus through GABAergic disinhibition.

The present study investigated the effect of morphine on synaptic transmission and long-term potentiation (LTP) in the dentate gyrus using rat hippocampal slice preparations. Field excitatory postsynaptic potential (fEPSP) and population spike (PS), evoked by stimulation of the perforant path, were recorded from the dentate molecular layer and the stratum granulosum, respectively. Following application of 10 microM morphine, PS amplitude increased gradually in 10 min and was eventually potentiated by approximately 50%. The phenomenon showed a concentration-dependent manner and was completely canceled by naloxone, a mu opioid receptor antagonist. Furthermore, morphine-induced PS augmentation was not detected in disinhibited hippocampal slices, which suggests that the inhibitory input to the dentate granule cells was required for the facilitatory effect of morphine. Neither fEPSP nor tetanus-induced LTP of PS was altered by morphine application. The data support the hypothesis that mu opioid receptor activity modulates inhibitory recurrent circuits in the dentate gyrus and thereby, indirectly plays a regulatory role for hippocampal excitatory neurotransmission.

Animals↗

[Acute respiratory failure due to inhalation of aerosol water proof agent].

A 65-year-old laundryman who suffered from cough, fever, and dyspnea was admitted to our hospital. Laboratory finding disclosed leukocytosis of peripheral blood, elevated CRP, and hypoxemia. Chest X-ray films showed diffuse interstitial nodular shadows in both lungs. The patient was given a diagnosis of pneumonia and treated with oxygen inhalation, antibiotics, and steroids. The abnormal findings disappeared rapidly, and the patient was discharged after 11 days. However, he was readmitted 3 days later with the same chest X-ray film findings as observed before. Examination of bronchoalveolar lavage fluid disclosed an increased neutrophil count. Transbronchial lung biopsy specimens revealed alveolar collapse, which was considered to have contributed to hypoxemia and ventilation perfusion mismatch. However, no signs of infiltration of inflammatory cells into alveolar walls, or of acute-phase interstitial edema, were observed. Environmental studies supported a strong relationship between the patient's symptoms and clothes waterproofing agent. From these findings, we reasoned that the inhalation of aerosol waterproofing agent containing fluoroplastics can induce respiratory failure.

Acute Disease↗

The chimeric protein, PEBP2 beta/CBF beta-SMMHC, disorganizes cytoplasmic stress fibers and inhibits transcriptional activation.

The chromosomal inversion 16(p13;q22) associated with human acute myeloid leukemia generates the chimeric PEBP2 beta/CBF beta-SMMHC gene. The PEBP2 beta/CBF beta portion of the chimeric polypeptide harbors most of the amino acid sequence of the PEBP2 beta/CBF beta protein, the non-DNA binding subunit of the heterodimeric transcription factor, PEBP2/CBF, whereas the SMMHC portion of the chimera consists of the rod domain of the smooth muscle myosin heavy chain molecule. In this study we examined the subcellular localization of the chimeric protein and its effect both on stress fibers and transcriptional activation by transfecting cDNA into tissue culture cells. The localization of the chimera was investigated by immunocytochemical staining of cells and was found to be both cytoplasmic and nuclear. One aspect of the effect of expression of the chimera was a drastic alteration of cell morphology. The cells appeared elongated and possessed long cytoplasmic processes. Double fluorescent labeling revealed disorganization of the stress fibers and an altered F-actin staining pattern in the transfected cells. Studies using a deletion mutant showed that both the PEBP2 beta/CBF beta and SMMHC domains are necessary for the induction of the morphological alteration. A significant proportion of the chimeric protein was retained in the cytoskeleton after detergent extraction of the cells and could be recuperated as a membrane fraction, suggesting that this is one of the probable sites of action of the PEBP2 beta/CBF beta-SMMHC protein. Another effect of the chimeric protein was inhibition of transcriptional activation dependent on the PEBP2/CBF binding DNA sequence. However, deregulation of PEBP2/CBF site dependent transcription by itself was not sufficient to induce cell morphological changes. Taken together, these results indicate that the PEBP2 beta/CBF beta-SMMHC chimeric protein acts at two levels, at the level of stress fiber organization and at the level of transcriptional activation. We suggest that the action of PEBP2 beta/CBF beta-SMMHC depends to a great extent on whether it is located in the cytoplasm or in the nucleus.

Acute Disease↗

Difference between PA700-like proteasome activator complex and the regulatory complex dissociated from the 26S proteasome implies the involvement of modulating factors in the 26S proteasome assembly.

The PA700-like proteasome activator complex was highly purified from porcine erythrocytes, and its properties were compared with those of the regulatory complex disassembled from the purified 26S proteasome. The molecular mass of the PA700-like complex, which comprises 25-110-kDa subunits, was estimated to be 800 kDa by Superose 6 gel filtration. This complex showed neither ATPase activity nor peptidase activity toward Suc-Leu-Leu-Val-Tyr-MCA. Nevertheless, it was possible to make a high molecular mass complex from the purified PA700-like complex by incubating with the 20S proteasome in the presence of ATP. In contrast, the regulatory complex dissociated from the 26S proteasome did not reconstitute a larger complex under the same conditions. The subunit composition of the PA700-like complex was similar but not identical to that of the regulator complex dissociated from the 26S proteasome: the former complex had a 25-kDa subunit which is absent in the latter, whereas the latter had two or three 43-kDa subunits lacking in the former. These results indicate that the purified PA700-like proteasome activator complex is structurally and functionally distinct from the regulatory complex dissociated from the 26S proteasome, implying the involvement of modulating factors in the 26S proteasome assembly.

Animals↗

GnRH inhibits neuronal activity in the ventral tegmental area of the estrogen-primed ovariectomized rat.

In urethane-anesthetized ovariectomized rats, estrogen-sensitive descending neurons were identified in the midbrain ventral tegmental area (VTA), based on estrogen-induced changes in the excitability in antidromic responses to midbrain central gray stimulation. Estrogen increased the threshold and decreased the firing rate of the identified neurons. Responses of the identified neurons to the microiontophoresis of gonadotropin-releasing hormone (GnRH) or D-Phe2, D-Ala6-GnRH, a behaviorally active analog, but not to glutamate or gamma-aminobutyric acid (GABA), depended on estrogen. In the ovariectomized rat, GnRH excited a few neurons; the analog had no effect. GnRH suppressed spontaneous or glutamate-induced firing in almost all neurons in the estrogen-primed rat. The analog had mixed effects. The facilitation of female rat sexual behavior induced by infusion of GnRH in the VTA is due to the inhibition of VTA neurons.

Animals↗

Anatomic segmental resection of the lung by thoracoscopy: an experimental study.

In patients who are unable to undergo a lobectomy for a small peripheral lung cancer, a partial thoracoscopic resection appears to be one viable alternative. However, since the regional lymphatics are disrupted in an anatomical fashion with a segmentectomy, it appears superior to a wedge resection. This experimental study was conducted to determine whether or not an anatomical segmental resection is feasible by thoracoscopy. A segmental resection of porcine lungs was performed using thoracoscopy. The segmental vessels were divided between ligatures. The segmental bronchus was divided by an endoscopic stapler. The intersegmental lung parenchyma was divided using a cotton dissector and a contact neodymium-yttrium aluminum garnet laser. Forty-three pigs were divided into seven groups as follows. Group 1: S1 + 2; group 2: S3; group 3: upper division; group 4: lower division; group 5: S6; group 6:S8; and group 7: S9 + 10. The operating times ranged from 145 +/- 15 min to 191 +/- 47 min. Blood loss ranged from 36 +/- 35 ml to 151 +/- 48 ml in all groups. The blood loss in the group with a resection of S6 and S9 + 10 was significantly greater than that of the other five groups. Most of the blood loss occurred during the division between the intersegmental planes. In conclusion, a thoracoscopic segmentectomy is considered to be technically feasible; however, further refinements in this technique are warranted before beginning clinical trials.

Animals↗

M3 muscarinic receptor mediates regulation of protein secretion in rabbit lacrimal gland.

PURPOSE: To identify which muscarinic receptor subtypes mediate protein secretion in isolated rabbit lacrimal glands. To compare protein secretory profiles in vitro with those in rabbit tears. METHODS: Rabbit lacrimal gland slices were incubated with carbachol in the presence and absence of different muscarinic antagonists. Protein secretion into the incubation medium was characterized with a Bio-Rad protein assay dye reagent in conjunction with Laemmli's method of SDS-PAGE. The medium protein profile was compared to that in tear samples. RESULTS: Dose dependent increases in protein secretion were elicited by carbachol between 10(-7) and 10(-4) M. During the first 20 min period, a maximal increase of 64% above the basal level was seen at the highest concentration. With 10(-4) M carbachol, the response was transient because after 100 min it decreased to its basal level. The increases in protein secretion caused by 10(-4) M carbachol were completely suppressed in the presence of 10(-5) M atropine. On the other hand, the relatively selective M1 antagonist, pirenzepine, at concentrations from 10(-6) M to 10(-4) M, had no effect on either the basal levels or the stimulatory effects of carbachol. Similarly, the relatively selective M2 antagonist, gallamine, at concentrations from 10(-6) M to 10(-4) M, had no effect on either of these levels. In contrast, the relatively selective M3 antagonist, 4-DAMP, at concentrations from 10(-6) M to 10(-4) M, progressively suppressed the stimulated level of protein secretion elicited by 10(-4) M carbachol without affecting the basal level. The protein profiles found in the tears and in the incubation medium were similar to one another. CONCLUSION: In vitro rabbit lacrimal gland protein secretion is comparable to that in vivo. Cholinergic-mediated control of rabbit lacrimal gland protein secretion occurs through stimulation of the M3 muscarinic receptor subtype.

Animals↗

Detection of cell adhesion molecules in lens epithelial cells of human cataracts.

PURPOSE: To detect the expression of cell adhesion molecules (CAMs), including beta integrins, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1, leukocyte-endothelial cell adhesion molecule-2, E-cadherin, and CD44, in cultured lens epithelial cells (LECs) of human cataracts. To show that LECs attach to cells or extracellular matrix components by the detected adhesion molecules. METHODS: A circular section of the anterior capsule with attached LECs obtained by anterior capsulotomy during cataract surgery was cultured in a well of an eight-chamber slide. The LEC immediately after surgery and the cell outgrowth beyond the capsular margin at 2 weeks of culture were observed after the culture was stained immunohistochemically. Functional assays of LEC growth on collagen- or laminin-coated plates were performed in the presence and absence of the antibody blocking the detected adhesion molecules. RESULTS: beta 1 integrin, ICAM-1, and CD44 were detected in both the original specimens and the cultured cells. When the antihuman anti-beta 1 integrin monoclonal antibody (mAb), anti-ICAM-1 mAb, or anti-CD44 mAb was added at 10 micrograms/ml to the incubation medium, LEC migration and proliferation were inhibited significantly on the collagen- or laminin-coated plates. When the mAb blocking these three CAMs were added each at 1 microgram/ml, LEC proliferation also were inhibited. CONCLUSIONS: beta 1 integrin, ICAM-1 and CD44 are all involved in LEC attachment and growth on collagen and laminin in vitro. It can be assumed that these CAMs are involved in adhesion of LECs to extracellular matrix components of the lens capsule. Understanding the characteristics of the adhesion molecules in LEC may lead to the development of a new approach to inhibit secondary cataract formation.

Antibodies, Monoclonal↗

Estrogen modifies the baroreceptor-induced responses of supraoptic vasopressin neurons in the ovariectomized rat.

Effects of estrogen (E2) and estrogen plus progesterone (EP) on the baroreceptor-induced response of the spontaneous discharge activity in the supraoptic (SON) vasopressin (AVP) neurons were examined in ovariectomized (OVX) female rats. An increase or a decrease in arterial blood pressure induced by intravenous injection of phenylephrine or nitroprusside, resulted in an inhibition or an acceleration of the discharge activity in the identified AVP neurons. The slopes that were derived from a least squares regression line for the arterial blood pressure and baroreceptor-induced responses of AVP neurons in both OVX + E2 and OVX + EP rats were statistically smaller (P < 0.05) than that in the control OVX rat. These results suggest a functional relationship between ovarian endocrine and autonomic functions in the female rat.

Animals↗

Purification and properties of the 26S proteasome from the rat brain: evidence for its degradation of myelin basic protein in a ubiquitin-dependent manner.

A ubiquitin(Ub)/ATP-dependent proteolytic complex (26S proteasome) was highly purified from the rat brain. The brain 26S proteasome consisted of 22-110 kDa subunits characteristic of the typical 26S proteasome on the basis of SDS-PAGE. The two-dimensional PAGE (NEPHGE and SDS-PAGE) pattern revealed that the pI values and molecular masses of the brain 26S proteasome subunits were similar to those of the subunits of 26S proteasomes purified from the rat liver and skeletal muscles. The enzymatic properties of the brain 26S proteasome were similar to those of the liver complex and also to the Ub-conjugate degrading activity in the cerebral cortex extract. Furthermore, it was found that the brain 26S proteasome was capable of degrading the myelin basic protein in a Ub-dependent manner. These results indicate that the brain contains the Ub-conjugate-degrading 26S proteasome, the subunit composition of which appears similar to those of the other tissues, and that the myelin basic protein may be a candidate physiological substrate for the brain 26S proteasome.

Animals↗

Osmolality- and angiotensin-induced responses in the AV3V neurons are affected by estrogen in the ovariectomized rat.

The effect of hyperosmolality (300, 320 mosmol/kg H2O) and angiotensin II (A II, 10(-8) and 10(-6) M) was tested on a total of 64 neurons within the periventricular part of the anteroventral third ventricle (AV3V) region in brain slice preparations obtained from ovariectomized (OVX) rats with or without chronic treatment of estradiol-17 beta (E2). Hypertonic perfusion with a 320 mosmol/kg H2O but not a 300 mosmol/kg H2O medium caused a significant increase in the firing discharge rate in OVX animals. Perfusion with either hypertonic medium had no effect in E2-treated rats. The neuronal firing discharge rate of neurons in OVX rats was increased following perfusion with 10(-6) M A II, but not affected following perfusion with 10(-8) M A II. In E2-treated rats, perfusion with neither 10(-8) nor 10(-6) M A II had any effect. These data suggest a dynamic relationship between the ovarian endocrine function and the central mechanisms regulating dipsogenic behavior and/or release of vasopressin in the female rat.

Angiotensin II↗

Thoracoscopic en bloc total esophagectomy with radical mediastinal lymphadenectomy.

OBJECTIVE: Total esophagectomy with en bloc mediastinal lymphadenectomy for cancer carries a substantial morbidity and mortality rate. To investigate the feasibility of thoracoscopic technique, we carried out an extensive laboratory study. Encouraged by our excellent results, we conducted a clinical trial. METHODS: From September 1994 to September 1995, 39 patients thoracic esophageal cancer lesions not invading surrounding organs underwent total esophagectomy with mediastinal lymphadenectomy by means of thoracoscopy. Ages ranged from 47 to 86 years. The procedures were conventional except for the thoracic portion, which was performed as a thoracoscopic procedure with six trocar holes instead of thoracotomy. All harvested lymph nodes were counted for each station. Spirometric data and plethysmographically determined vital capacity were measured before and after operation for all patients. RESULTS: All procedures were accomplished as scheduled, and none was converted to open thoracotomy. The operating time was 200 +/- 41 minutes (mean +/- standard deviation). Estimated blood loss was 270 +/- 157 ml. The harvested lymph nodes numbered 19.7 +/- 11.1 per patient. Seventeen patients (45%) had positive lymph nodes. There were no in-hospital deaths within 30 days. Twenty-two patients did not require postoperative ventilatory support. Vital capacity decreased to 85% +/- 11% of the preoperative values, and forced expiratory volume in 1 second decreased to 82% +/- 16%. CONCLUSIONS: Thoracoscopic mediastinal lymphadenectomy is technically feasible, and its completeness is comparable to that of the open technique. The decline in pulmonary function is significantly less than that seen in our previous experience with the open technique.

Aged↗

Properties of 26S proteasome purified from rat skeletal muscles: comparison with those of 26S proteasome from the rat brain.

A ubiquitin/ATP-dependent proteolytic complex (26S proteasome) was highly purified from rat skeletal muscles and its enzymatic properties were compared with those of the brain 26S proteasome. The purified 26S proteasome comprises 22-110 kDa subunits characteristic of the typical 26S proteasome on the basis of SDS-PAGE. The two-dimensional PAGE (NEPHGE and SDS-PAGE) pattern revealed that the pI values and molecular masses of the muscle 26S proteasome subunits were similar but not identical to those of the subunits of 26S proteasome purified from the rat brain. The enzymatic properties of the muscle 26S proteasome were very similar to those of the brain enzyme in substrate specificity and inhibitor susceptibility. The specific activities of the muscle 26S proteasome toward three fluorogenic peptide substrates were indistinguishable from those of the brain enzyme.

Animals↗

Transfusion-associated graft-versus-host disease diagnosed by polymerase chain reaction analysis of DNA microsatellites: an autopsy case with immunohistochemical investigation.

An autopsy case of transfusion-associated graft-versus-host disease (TA-GVHD) is reported with immunohistochemical investigation and polymerase chain reaction (PCR) analysis. In a 58-year-old male, esophagectomy for carcinoma was performed with a transfusion of 4 units of fresh whole blood. Diarrhea, fever, erythematous rash, pain and leukopenia occurred with an onset 11 days after the operation. He died of sudden dyspnea 29 days after the operation. At autopsy, histological examinations revealed lichenoid lesion in the skin, injury of mucosal epithelia in the digestive tract and damage of interlobular bile ducts in the liver. Immunohistochemical investigation suggested the association between these lesions and CD8-positive T lymphocytes. Severe disturbances of bone marrow and lymphoid organs were accompanied with gram-positive cocci infection in the lungs, esophagus and small intestine. PCR analysis of DNA at microsatellite loci, human growth hormone (HGH) and apolipoprotein B (Apo B), showed DNA chimerism and established the definitive diagnosis of TA-GVHD.

Antigens, CD↗