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Biomedical subjects

H Imai

Publications and source records attributed to H Imai.

At least 253 records · Page 14Linked to original sources

Production of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in mildly cirrhotic rat liver.

We have studied the production of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in liver of normal rats and in rats with mild cirrhosis induced by carbon tetrachloride inhalation, to demonstrate the production of these fibrinolytic components and their pathophysiologic role in the liver in vivo. Immunohistochemical study of paraffin-embedded liver sections and fibrin autography of frozen sections showed that the normal rat liver produces very little t-PA or PAI-1. On the contrary, striking t-PA activity and both t-PA and PAI-1 antigens were observed in the cirrhotic liver. Both t-PA and PAI-1 in plasma were also markedly increased in the cirrhotic rats. Because the hepatocyte can internalize t-PA or PA/PAI-1 complexes from circulation, Northern blot analysis of the total liver RNA was performed to demonstrate the endogenous synthesis of t-PA and PAI in the liver. Although the normal liver hardly expresses either t-PA or PAI-1 mRNA, striking t-PA and PAI-1 mRNA expression was observed in the liver of rats with mild cirrhosis. These data demonstrate that t-PA and PAI-1 production is strongly upregulated in the liver in rats with mild cirrhosis. These fibrinolytic components, whose production is closely associated with liver failure, may play important roles in the regulation of hepatocyte proliferation and liver regeneration in vivo.

Animals↗

Tubulointerstitial nephritis with renal tubular acidosis and asymptomatic primary biliary cirrhosis accompanied by antibody to a 52-kDa mitochondrial protein alone.

We report a patient presenting with a mixed type of renal tubular acidosis, who demonstrated anti-mitochondrial antibodies on immunofluorescent study. However, study of anti-M2 antibody (enzyme immunoassay) was negative. Renal biopsy revealed lymphocyte infiltration in the interstitium compatible with chronic tubulointerstitial nephritis. Liver biopsy demonstrated a mild degree of primary biliary cirrhosis (PBC) but biochemical liver function tests were normal, resulting in a diagnosis of asymptomatic PBC. Using affinity chromatography conjugated with the patient's IgG, we purified a 52-kDa protein from a porcine renal mitochondrial fraction. This protein was identified as a component of a mitochondrial multienzyme complex such as dihydrolipoamide acyltransferase of the branched-chain alpha-keto acid dehydrogenase complex (BCKD), based on the molecular mass analysis and partial amino acid sequence of the purified protein. This is the first report of the detection of antibody to 52-kDa mitochondrial protein alone in a patient who showed predominantly tubulointerstitial damage in the kidney rather than liver damage.

Acidosis, Renal Tubular↗

[Two cases of metastatic lung cancer examined by bronchoscopic cytology].

We herein report two cases of metastatic lung cancer examined with bronchoscopic cytology. The first case involved a 43-year-old female, who had undergone low anterior resection of the rectum for rectal cancer three years earlier. Routine chest X-ray showed a nodular lesion in the left upper area. Bronchoscopic examination revealed a mass occluding the left upper bronchus. Simultaneous bronchoscopic biopsy and washing cytology were performed. The cytological specimen consisted of cell clusters with tall columnar epithelium arranged in a palisading manner. The cytological findings strongly suggested metastatic adenocarcinoma originating from the colorectal region. The patient died from respiratory failure. Autopsy confirmed metastatic deposit of adenocarcinoma in the lung. Histologically, the tumor invaded the overlying bronchial wall and was exposed in the lumen. The second case was an 80-year-old female, who had been diagnosed as gastric cancer by the endoscopic examination one year earlier. She had refused surgical treatment. Routine chest X-ray showed reticulonodular lesions disseminated throughout the bilateral lungs. Bronchial endoscopy presented edematous mucosa of the right lower bronchus. Brushing cytology as well as punch biopsy were taken. Cytological examination revealed atypical cells with increased N/C ratio and reduced cohesiveness. The lesion was diagnosed as metastatic adenocarcinoma of gastric origin from cytological findings and clinical history. The patient died from respiratory failure. Postmortem examination revealed cancer cells in the lymphatic channels of the bronchial wall. Our two cases indicate that bronchoscopic cytology is useful for estimating the origin of metastatic cancer.

Adenocarcinoma↗

[A 43-year-old woman with 18 years history of parkinsonism].

We report a 43-year-old woman who died after 18 years history of parkinsonism. She was well until 25 years of the age (1976) when she noted a difficulty in stepping her feet. In the next year, she started to drag her feet. She was treated with levodopa with good response, however, she developed dyskinesia when she was 33 years of the age. She was evaluated in another hospital in 1984. She showed normal intelligence, normal ocular movement, masked face, small voice, small step gait, stooped posture, freezing of the gait, retropulsion, and cogwheel rigidity in limbs. No tremor or ataxia was noted. She received left ventrolateral thalamotomy at that time. Rigidity on the right side markedly reduced, however, she continued to show bradykinesia and motor fluctuations. On August 1 of 1994, she developed fever of 40 degrees C and dyspnea. On the next day, she expired from acute respiratory distress. She was able to walk unsupported until just before her last admission. The patient was discussed in a neurological CPC. The chief discussant arrived at the conclusion that this patient had Lewy body-positive young onset Parkinson's disease. Opinions were divided into two groups, i.e., young onset Lewy-body positive Parkinson's disease and Lewy-body negative young onset parkinsonism. Post-mortem examination revealed moderate loss of pigmented neurons in the substantia nigra more in the ventro-lateral part. Lewy bodies were found in the remaining neurons. Lewy bodies were more frequently seen in the locus coeruleus, although neuronal loss was less prominent in the locus coeruleus. The dorsal vagal motor nucleus showed moderate loss of neurons. Otherwise, the central nervous system was unremarkable. To our knowledge, this patient had the second youngest age of the onset so far reported in the literature for Lewy-body positive typical Parkinson's disease.

Adult↗

Infection of human papillomavirus (HPV) and p53 over-expression in human female genital tract carcinoma.

Inactivation of p53 gene products either by mutation or by complex formation with E6 oncoprotein encoded by high risk HPV appears to be a common event in cervical carcinogenesis. This study was designed to clarify this association in 41 primary cervical, 15 endometrial, 3 ovarian and one rectal carcinomas. Polymerase chain reaction analysis revealed presence of high risk HPV in 36 (88%) cervical, 5 (33%) endometrial and none of ovarian and rectal carcinomas. HPV 16 was found in 14 cervical carcinomas, HPV 18 in 19 cervical and 2 endometrial carcinomas and HPV 33 in 28 cervical and 5 endometrial carcinomas. Expression of tumor suppressor protein p53 by using polyclonal antibody CM-1, was detected in 28 (68%) cervical, 7 (47%) endometrial, 2 (66%) ovarian and one (100%) rectal carcinoma. Twenty six cervical and 3 endometrial carcinoma cases were positive for both high risk HPV and p53. We conclude that beside cervical carcinoma HPV infection is not uncommon in endometrial carcinoma and in our experimental design there is no inverse correlation between HPV infection and p53 over-expression in a variety of the tumors analysed in the present study.

Adult↗

[A 56-year-old man with fever, backache and tetraparesis].

We report a 56-year-old man who developed progressive paraparesis. He was apparently well, except for left Bell's palsy which developed on May 9 of 1994, for which he received stellate ganglion block on the left side more than ten times until July 2nd of 1994, when he noted pain in his left shoulder and in his lumbar region. On July 5th, he noted some difficulty in urination. On July 6th, he noted tingling sensation in his four extremities and difficulty in gait. He was admitted to another hospital where he was treated with intravenous infusion of glycerol. After this treatment, his gait and sensory disturbance showed some improvement, however, on July 7th, his shoulder and lumbar pain worsened, and he became unable to stand. His temperature went up to 39 degrees C on the next day. Lumbar CSF on that day contained 119 cells/microliters, 112 mg/dl of protein, and 53 mg/dl of sugar. He was transferred to our hospital on July 14th. His past medical history revealed that he had suffered from frequent bouts of osteomyelitis since the age of 13 years. He was operated on several times on osteomyelitis. He had been treated on his tooth ache until shortly before the onset of the present illness. He also received steroid hormone for his Bell's palsy. On admission, his consciousness varied from alert to stupor. His BP was 150/100 mmHg, HR 98/min and regular, BT 39.4 degrees C. The bulbar conjunctiva appeared somewhat icteric. Otherwise, general physical examination was unremarkable. On neurologic examination, there was no apparent dementia. Higher cerebral functions appeared intact. The optic discs were flat. Pupils were round and isocoric reacting to light and accommodation promptly. Ocular movements were full without nystagmus. Some exophthalmos was noted bilaterally. The sensation of the face and facial muscles were intact. The remaining cranial nerves also appeared intact. Nuchal rigidity was present. He was unable to stand or walk. Muscle strength was markedly diminished in all four limbs; manual muscle testing revealed 1 to 2/5 weakness in both upper and lower extremities bilaterally. Muscle stretch reflexes were decreased or lost in both upper and lower limbs, but the plantar response was extensor on the right. Sensation appeared to be diminished in legs, but detail was not clear because of disturbance of consciousness. Pertinent laboratory findings were as follows: WBC 12,800/microliter, GPT 58 IU/l, total bilirubin 2.65 mg/dl, and CRP 16.8 mg/dl. Cerebrospinal fluid contained 34 cells/microliter (approximately two thirds were neutrophils), RBC 1,110/microliter, 2,949 mg/dl of protein, and 119 mg/dl of glucose; stapylococcus aureus was cultured from the CSF. Myelogram showed a filling defect in the anterior epidural space between the low thoracic and the upper lumbar region. The patient was treated with cephotaxim, aminobenzyl penicillin, and chloramphenicol. On the second hospital day, his BT was still 39 degrees C and he was agitated His weakness was worse than the previous day. Spinal MRI was attempted; as he was agitated 5 mg of diazepam was given intravenously at 4 PM. His respiration was rapid and somewhat shallow. At 6 PM, gadolinium DTPA was injected intravenously; at that time, he was breathing and pupils were 3 mm on both sides. At 6:35 PM, an examiner noted that he stopped breathing; the left pupil was dilated to 5 mm. Cardiopulmonary resuscitation was initiated immediately, and intubation was performed. He was placed on a respirator. His blood pressure did not reach 100 mmHg; he was in deep coma. Cardiac arrest occurred at 8:53 AM on the next morning. The patient was discussed in a neurological CPC. Most of the participants thought that the patient had either spinal epidural empyema or spinal subdural abscess. The question was what might be the original focus of infection. Three possibilities were considered, i.e., stellate ganglion block, teeth infection, and osteomyelitis...

Back Pain↗

[A 91-year-old man with a stroke, hypertension, and renal failure].

We report a 91-year-old man who had a stroke and died of renal failure. He had been treated for hypertension since 20 years before the onset of the present illness. In addition, he was operated on a gastric cancer 17 years previously. Otherwise he was doing well until May 29, 1991 (when he was 87-year-old) when he had sudden onset of dysarthria and right facial weakness. He was admitted to our hospital. On admission, general physical examination was unremarkable, and neurologic examination revealed a mentally sound man with slight dysarthria, right facial weakness, orolingual dyskinesia, and dysequilibrium in which he showed difficulty in tandem gait; however, no cerebellar ataxia was noted. A cranial CT scan revealed leukoaraiosis with multiple low density areas in the cerebral white matter. His BUN was 37 mg/dl and Cr 2.2 mg/dl. His neurologic symptoms cleared within the next few weeks and he was discharged with ticlopidine 100 mg q.d.. He had been doing well after the discharge except for gradual worsening of his renal function; his BUN was 65 mg/dl and Cr 3.27 mg/dl in April of 1994. On March 10, 1995, he fell down and hit his back; he became unable to walk because of pain, and he was admitted again on March 16, 1995. On admission, his blood pressure was 170/80 mmHg. There was an 1 + pitting pretibial edema; otherwise general physical examination was unremarkable. Neurologic examination revealed an alert and oriented man, however, Hasegawa's dementia scale was 23/30. Higher cerebral functions as well as cranial nerves were intact. He showed some unsteadiness of gait, however, no motor weakness or ataxia was noted. Deep tendon reflexes were diminished, but Chaddock sign was positive bilaterally. Vibration was diminished in the feet, however, pain and touch sensations were intact. Laboratory examination revealed a compression fracture of the twelfth thoracic vertebra. Blood count and chemistries were as follows; Hb 7.6 g/dl, Hct 23.3%, TP 6.0 g/dl, Alb 3.6 g/dl, BUN 87 mg/dl, Cr 4.53 mg/dl, T-Chol 174 mg/dl, HDL-Chol 49 mg/dl, Glu 156 mg/dl, Na 142 mEq/L, K 5.4 mEq/L, Cl 115 mEq/L. A urine specimen contained 1 + protein and 1 + glucose, and the sediments contained hyaline casts. A cranial CT scan was essentially same as that taken four years ago. His hospital course was complicated with pneumonia, congestive heart failure, and progressive renal failure. He was treated with intravenous fluid, chemotherapy, and other supportive measures, however, he expired from respiratory failure on April 30, 1995. He was discussed in a neurologic CPC, and the chief discussant arrived at the conclusion that the patient had Binswanger's disease in the brain, benign nephrosclerosis from arteriolosclerosis due to hypertension, congestive heart failure, and pneumonia. Opinions were divided regarding the question as to whether or not this patient had Binswanger's disease. Although his cranial CT scan revealed leukoaraiosis, his dementia and gait disturbance was only mild until his fall on March, 1995. Clinical features did not conform to those of Binswanger's disease. Postmortem examination of the right hemisphere revealed wide spread atherosclerosis and arteriolosclerosis. The kidney showed benign nephrosclerosis due to arteriolosclerosis. Sclerotic changes were also seen in the coronary arteries and the left middle cerebral artery with 70% stenosis. Myelin stain showed diffuse myelin pallor of the cerebral white matters with scattered small infarcts. Arterioles in the white matter showed arteriolosclerosis. Small infarcts were also seen in the putamen and in the thalamus. This patient appeared to have had circulatory disturbance of the white matter which is the basic abnormality causing Binswanger's disease. However, white matter changes in this patient were not quite severe enough to make a pathologic diagnosis of Binswanger's disease.

Aged↗

Effect of chloride on the thermal reverse reaction of intermediates of iodopsin.

Among the intermediates in the bleaching process of iodopsin, a chicken red-sensitive cone visual pigment, the batho and meta I intermediates (batho and meta I) formed at low temperatures revert to the original iodopsin by thermal reactions [Yoshizawa & Wald (1967) Nature 214, 566-571; Imamoto, Imai, Yoshizawa, & Shichida (1994) FEBS Lett. 354, 165-168]. In order to elucidate the relationship between Cl- binding to iodopsin and these reverse reactions, we have prepared a sample of iodopsin whose Cl(-)-binding site is vacant (anion-unbound iodopsin) and compared the thermal reactions of its batho and meta I intermediates with those of Cl(-)-bound (native) and nitrate-bound iodopsins. The reverse reaction from batho is observed in both Cl(-)-bound and anion-unbound iodopsins, while the reaction from meta I is observed only in Cl(-)-bound iodopsin. These results indicate that Cl- binding is indispensable for the reverse reaction from meta I, but not from batho. The reverse reaction from meta I has been further investigated as a function of Cl- concentration, and the dissociation constant of Cl- in meta I is estimated to be approximately 20 mM. This value is about 200 times larger than that of iodopsin (0.1 mM), and close to the physiological Cl- concentration in photoreceptor cells, suggesting that Cl- could be released from the protein moiety during the bleaching of iodopsin.

Animals↗

Difference in molecular properties between chicken green and rhodopsin as related to the functional difference between cone and rod photoreceptor cells.

Using low-temperature spectroscopy, we have investigated the photobleaching process of chicken green, a green-sensitive cone visual pigment present in chicken retina, and compared it to that of rhodopsin, a rod visual pigment. Like rhodopsin, chicken green converts to all-trans-retinal and opsin through batho, lumi, and meta I, II, and III intermediates. However, all of the intermediates of chicken green except lumi, are less stable than the corresponding intermediates of rhodopsin. While early intermediates, batho and lumi are similar in absorption maxima between chicken green and rhodopsin, the meta intermediates of chicken green are about 20 nm blue shifted from those of rhodopsin. Low-temperature time-resolved spectroscopy was applied to estimate the thermodynamic properties of meta intermediates, and it indicated that the less stable properties of meta II and III intermediates of chicken green originate from the smaller activation enthalpies. The decay of the meta II intermediate of chicken green is greatly suppressed when a chicken green sample is irradiated at alkaline conditions while the net charge becomes similar to that of rhodopsin at neutral conditions. These results strongly suggest that the functional properties of chicken green that are different from those of rhodopsin are regulated by the dissociative amino acid residue(s).

Avian Proteins↗

Age-related change in redox state of human serum albumin.

Human serum albumin (HSA) is the mixture of human mercaptalbumin (HMA, reduced form) and human nonmercaptalbumin (HNA, oxidized form). We developed a rapid and concise HPLC system to obtain the clear resolution of HSA into HMA and HNA, using an Asahipak GS-520H column. The mean value of the fraction of HMA (f(HMA)) for healthy young male subjects was 0.76 +/- 0.04 (n = 54). However, the f(HMA, 60-90) value for healthy elderly subjects (where the numbers in brackets indicate the range of ages) was 0.48 +/- 0.06 (n = 183). In healthy elderly subjects, f(HMA) was significantly lower than in healthy young male subjects, indicating that HSA in the elderly becomes more oxidized than in the young subjects. Consequently, we suggest that one of the important functions of serum albumin could be to participate in the maintenance of a constant redox potential in the extracellular fluids, thus securing a certain redox buffer capacity. f(HMA) on HSA might reflect this redox buffer capacity with age.

Adult↗

Purification and low temperature spectroscopy of gecko visual pigments green and blue.

We purified two kinds of visual pigments, gecko green and gecko blue, from retinas of Tokay geckos (Gekko gekko) by two steps of column chromatography, and investigated their photobleaching processes by means of low temperature spectroscopy. Absorption maxima of gecko green and blue solubilized in a mixture of 3-[(3-cholamidopropyl)dimethylammonio]-1- propanesulfonate (CHAPS) and phosphatidylcholine were 522 and 465 nm, respectively, which are close to those observed in the photoreceptor cells. Low temperature spectroscopy identified six intermediates in the photobleaching process of gecko green; batho (lambda max = 569 nm), BL (lambda max = 519 nm), lumi (507 nm), meta I (approximately 486 nm), meta II (approximately 384 nm), and meta III intermediates (approximately 500 nm). In contrast to the high similarity in amino acid sequence between gecko green and iodopsin [Kojima, D., et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 6841-6845], the batho-green did not revert thermally to original gecko green but converts to the next intermediate. The photobleaching process of gecko blue was investigated by low temperature spectroscopy, and three intermediates, meta I (lambda max = approximately 470 nm), meta II (lambda max = approximately 370 nm) and meta III (lambda max = approximately 475 nm), were identified. A comparative study on the thermal behavior of meta intermediates revealed that the thermal stability of meta II intermediate of both of the gecko visual pigments is lower than that of metarhodopsin II. The result supports the idea that both the gecko visual pigments are cone-type ones.

Animals↗

A combination of livedo racemosa, occlusion of cerebral blood vessels, and nephropathy: kidney involvement in Sneddon's syndrome.

A 59-year-old woman with retinal vein thrombosis and livedo racemosa had hematuria (4+) and proteinuria (1.7 g/day). Skin biopsy showed swollen blood vessel walls with infiltration of mononuclear cells, which were compatible with livedo racemosa (vasculitis). Magnetic resonance imaging (MRI) of the brain demonstrated multiple lacunar infarctions in the basal ganglia and white matter. Renal biopsy showed that small round cells had infiltrated into the interstitium, and a reticular structure was observed in the glomerular hilus. An amorphous substance composed of a single cell was present in the glomerular capillary lumen. Immunofluorescent study demonstrated the deposition of only IgA, in a segmental pattern differing from the diffuse global mesangial pattern seen in IgA nephropathy. After combined therapy including 40 mg/day prednisolone, 50 mg/day cyclophosphamide, antiplatelet drug, and anticoagulant was started, proteinuria and hematuria improved to 0.5 g/day and 2+, respectively, at the time of discharge. Sneddon's syndrome is a rare entity characterized by livedo racemosa and cerebrovascular lesions. In our patient with livedo racemosa, occlusion of cerebral blood vessels, and nephropathy with segmental immunoglobulin A (IgA) deposition, no antiphospholipid antibodies were detected on routine examination. Dermatologists, neurologists, psychiatrists, and nephrologists should be aware of the existence of Sneddon's syndrome with nephropathy (LI-O-N).

Antibodies, Antiphospholipid↗

Microsatellite instability in human prostate cancer.

Microsatellite instability (MSI) was examined at 36 loci, and found in 9 (43%) of the 21 prostatic cancers. A loss of heterozygosity had occurred in five cases (24%). MSI did not correlate with clinical stage, but might play a role in the development of a subset of prostate cancers.

Adult↗

Molecular cloning and functional expression of a cDNA for rat phospholipid hydroperoxide glutathione peroxidase: 3'-untranslated region of the gene is necessary for functional expression.

A full-length cDNA clone for phospholipid hydroperoxide glutathione peroxidase (PHGPx) was isolated from a rat brain. The cDNA was 0.761 kb in length and encoded 170 amino acids, which included a TGA-encoded selenocysteine at residue 46. The protein has a calculated molecular mass of 19,473 Da. We succeeded in the transient functional expression of a full-length cDNA for PHGPx, which includes the 3'-UTR, in COS-7 cells at the first attempt. Deletion of the 3'-UTR prevented the expression of the PHGPx activity and the incorporation of [75Se]selenious acid into the monomeric 19.7 kDa PHGPx protein. Thus, the 3'-UTR of the cDNA for PHGPx was required for the functional expression of PHGPx. Northern blot analysis demonstrated that the mRNA for PHGPx was widely expressed in normal rat tissues, especially in the testis. The mRNA levels of PHGPx in the cultured cells such as hepatomas, neuronal cells, nephroblastoma, and mammary myo-epithelial cells were higher than those of the tissues. The ratio of PHGPx to cytosolic glutathione peroxidase (cGPx) was significantly high in the testis and relatively high in the cultured cells. The mRNA levels of PHGPx in tissues were lower than those of cGPx.

Amino Acid Sequence↗

Non-muscle myosin as target antigen for human autoantibodies in patients with hepatitis C virus-associated chronic liver diseases.

Three patients with hepatitis C virus (HCV)-related chronic liver disease were shown to have autoantibodies strongly reacting with cytoskeletal fibres of non-muscle cells. The heavy chain of non-muscle myosin microfilament was the main target for those autoantibodies, as determined by (i) cell and tissue immunofluorescence studies showing colocalization with an anti-myosin antibody prototype; (ii) primary reactivity in immunoblotting with a 200-kD protein, using either MOLT-4 cells, human platelets, or affinity-purified non-muscle myosin as antigen extract; and (iii) immunoblotting of similar immunoreactive fragments in papain-digested MOLT-4 cell extracts, by using those human sera and antibody prototype. Autoantibodies to non-muscle myosin heavy chain were not previously reported in patients with chronic liver diseases, especially in those associated with HCV infection.

Aged↗