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Biomedical subjects

A Sakamoto

Publications and source records attributed to A Sakamoto.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Electroconvulsive therapy for the depressive patients associated with chronic pain].

In five depressive patients associated with chronic pain, the efficacy of electroconvulsive therapy (ECT) for pain relief was evaluated retrospectively. In all of the patients treatment with tricyclic antidepressant medication was not successful, but ECT alleviated or diminished the chronic pain associated with depression. It seems that ECT as a treatment for chronic pain in patients with depression should be taken into consideration in cases in which other treatments have failed.

Adult↗
PubMed1998

Immunohistochemical evidence for a macrophage scavenger receptor in Mato cells and reactive microglia of ischemia and Alzheimer's disease.

Macrophage scavenger receptors (MSR) are implicated in the development of atherosclerosis and amyloid b-protein deposition in Alzheimer's disease. However, histopathological studies of MSR expression in human tissues have been hampered by a lack of specific antibodies. Using MSR-deficient mice, we successfully raised a novel monoclonal antibody against human MSR together with high-titer antisera. These antibodies specifically recognized human tissue macrophages and human MSR protein purified from differentiated THP1 cells. In normal brain, MSR staining was mainly distributed to the perivascular cells, which correspond to Mato's fluorescent granular perithelial cells (Mato cells). In the lesions of ischemia and Alzheimer's disease, a subset of microglia stained positive for MSR. These novel antibodies are useful tools for analysis of MSR expression in human tissues.

Alzheimer Disease↗
PubMed1998

Cys2/His2 zinc-finger protein family of petunia: evolution and general mechanism of target-sequence recognition.

The EPF family is a group of Cys2/His2zinc-finger proteins in petunia. In these proteins, characteristically long spacer regions have been found to separate the zinc fingers. Our previous DNA-binding studies demonstrated that two-fingered proteins (ZPT2-1 and ZPT2-2), which have spacers of different lengths, bind to two separate AGT core motifs in a spacing specific manner. To investigate the possibility that these proteins might distinguish between the target sequences on the basis of spacing between the core motifs, we screened petunia cDNA library for other proteins belonging to this family. Initial screening by PCR and subsequent cloning of full-length cDNAs allowed us to identify the genes for 10 new proteins that had two, three or four zinc fingers. Among the two-fingered proteins the spacing between zinc fingers varied from 19 to 65 amino acids. The variation in the length of spacers was even more extensive in three- and four-fingered proteins. The presence of such proteins is consistent with our hypothesis that the spacing between the core motifs might be important for target sequence recognition. Furthermore, comparison of diverse protein structures suggests that three- and two-fingered proteins might have resulted due to successive loss of fingers from a four-fingered protein during molecular evolution. We also demonstrate that a highly conserved motif (QALGGH) among the members of EPF family and other Cys2/His2 zinc-finger proteins in plants is critical for the DNA-binding activity.

Amino Acid Sequence↗
PubMed1998

Ultrastructural and immunohistochemical changes of fluorescent granular perithelial cells and the interaction of FGP cells to microglia after lipopolysaccharide administration.

Fluorescent granular perithelial (FGP) cells introduced by Mato et al. (1979, 1980, 1981) are situated in the Virchow-Robin space of cerebral microvessels and exhibit a marked uptake capacity for the endo- and exogenous materials in physiological conditions. That is, the FGP cells are the perivascular macrophage lineage enclosed by a basal lamina and glia limitans and are distributed between blood vessels and cerebral parenchyma. As reported previously, the FGP cells were distinguishable from microglia and pericytes in their morphology, location, and epitopes on their cytoplasmic membrane. On the other hand, it is established that microglia are upregulated by lipopolysaccaride (LPS) administration, but it remains unsettled whether the FGP cells, the perivascular macrophagic cells, are activated by LPS or not and what role the FGP cells play in the upregulation of microglia. Thus far, the morphological relationship between FGP cells and microglia in the process of upregulation has not been clarified. Thirty-six 7-month-old Wistar male rats were employed. The animals were sacrificed at 2, 5, 10, 24, and 72 h after the intravenous administration of 500 microg/kg of LPS. The FGP cells and microglia in their cerebral cortex were studied with immunohistochemical and electron microscopical techniques. The findings of the present study indicated that the majority of FGP cells were upregulated by LPS from the results of immunohistochemical and morphological data, but some of them tended to degenerate. Furthermore, in the time course after LPS administration, microglia were also upregulated and approached the microvessels and occasionally contacted the FGP cells directly. From these findings, it is hypothesized that FGP cells may significantly influence the mobilization and upregulation of microglia caused by LPS administration.

Animals↗
PubMed1998

Immunohistochemical study of p21WAF1 and p53 proteins in prostatic cancer and their prognostic significance.

Mutations of p53 tumor suppressor gene occur in a subset of aggressive prostatic carcinomas and are detectable by immunohistochemistry. However, it is uncertain whether p53 overexpression really reflects p53 gene mutation or loss of p53 function. p21WAF1, an inhibitor of cyclin-dependent kinases, is activated by wild-type p53 protein, not by mutant type. Therefore, it is possible that combined analysis of p21WAF1 and p53 proteins aids in determining the functional status of p53 immunostaining. Routinely processed prostatic tissues from 60 patients with prostatic adenocarcinomas were examined by immunohistochemistry for p21WAF1 and p53 expression. As for tissue distribution, p21WAF1 protein was expressed mostly in the luminal layers, in contrast, p53 protein was restricted to the basal layers of benign prostatic glands. In prostatic adenocarcinomas, p21WAF1 protein was more likely to be expressed in well-differentiated areas; in contrast, p53 protein was more likely in poorly differentiated areas in the tumors. The percentage of positive nuclear areas for p21WAF1 and p53 proteins in prostatic adenocarcinomas, assessed by CAS200 computerized image analyzer, were 8.6+/-10% and 16+/-14% (mean+/-SE), respectively. The survival study showed that the p53+/ p21- phenotype showed poorer prognosis than p53+/p21+. Multivariate analysis showed that p21WAF1 expression, clinical stage, and Gleason score were independent prognosticators. In conclusion, p21WAF1 immunohistochemistry is a useful method for interpretation of p53 immunohistochemical results. Combined analysis by p21WAF1 and p53 immunostaining would predict the patient survival more accurately than p53 immunostaining alone.

Adenocarcinoma↗
PubMed1998

Transesophageal echocardiographic evaluation during negative-pressure ventilation using the Hayek oscillator.

OBJECTIVES: To evaluate the effects of negative-pressure ventilation (NPV) on hemodynamics using the Hayek oscillator (Breasy Medical Equipment, London, UK) and to determine whether the oscillation frequency can modify the hemodynamics, assessed by transesophageal echocardiography (TEE). DESIGN: A prospective study. SETTING: A university hospital. PARTICIPANTS: Eleven American Society of Anesthesiologists class I patients undergoing orolaryngeal surgery. INTERVENTIONS: The ultrasound probe was inserted under general anesthesia. After baseline measurements were determined during spontaneous breathing, the frequency was changed from 30 to 60 to 120 cycles/min, consecutively. The left ventricular end-diastolic area (LVEDA), end-systolic area (LVESA), fractional area change (LVFAC), and end-systolic wall stress (ESWS) were determined. The velocities of the pulmonary artery (PA) flow, pulmonary venous (PV) flow, and transmitral flow were measured by pulsed Doppler techniques. MEASUREMENTS AND MAIN RESULTS: PaO2 increased and PaCO2 decreased significantly. NPV caused a significant increase in the LVEDA, whereas it did not significantly change the PA velocity. ESWS, an index of afterload, remained unchanged. CONCLUSION: The authors conclude that NPV using the Hayek oscillator induces an increase in the LVEDA without any changes in PA velocity, suggesting increased transmural pressure rather than increased preload, and that the three different frequencies do not modify the effects on the hemodynamics.

Adolescent↗
PubMed1998

Metabolic engineering of rice leading to biosynthesis of glycinebetaine and tolerance to salt and cold.

Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 micromol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 M NaCl [corrected] inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.

Acclimatization↗
PubMed1998

Desensitization of ET(A) endothelin receptor-mediated negative chronotropic response in right atria--species difference and intracellular mechanisms.

1. Desensitization of ET(A) endothelin receptor (ET(A)R) was compared between the rat and guinea-pig with regard to negative chronotropic response (NC) in the right atria (RA). 2. ET-1 (100 nM) produced distinct NC in the presence of BQ788 (300 nM), and positive chronotropic response (PC) in the presence of BQ123 (1 microM) in both species, showing that ETAR and ET(B) endothelin receptor (ET(B)R) mediate NC and PC, respectively. 3. Repetitive applications of ET-1 (50 nM) desensitized PC, and the second application only induced a strong NC in both species. Later applications of ET-1 produced virtually no response in the rat RA, whereas they produced BQ123-sensitive NCs repetitively in guinea-pig RA, exhibiting marked species difference in desensitization of ETAR-mediated NC. 4. Pretreatment with staurosporine (100 nM) prevented desensitization of ET(A)R in the rat RA altogether. However, phorbol 12-myristate 13-acetate (PMA, 300 nM) failed to induce, but rather hampered, desensitization of ET(A)R. 5. Partial amino acid sequencing of ET(A)Rs, spanning from the 2nd through the 4th intracellular loops, revealed that all the potential Ser/Thr phosphorylation sites, including a protein kinase C (PKC) site, are conserved among guinea-pigs, rats, rabbits, bovines and humans. 6. In guinea pig RA, pretreatment with okadaic acid (1 microg ml(-1)) and PMA did not facilitate desensitization of ET(A)R whereas these agents successfully desensitized ETAR during combined stimulation of beta-adrenoceptor and ET(A)R by isoproterenol (300 nM) and ET-1 (100 nM). 7. These results suggest that species differences in desensitization of ET(A)R are not caused by differences in the site(s) of, but caused by differences in the environment for phosphorylation of the receptor. Desensitization of ET(A)R appears to require phosphorylation of the receptor by PKC as well as a kinase stimulated by beta-adrenoceptor activation.

Animals↗
PubMed1998

Seven zinc-finger transcription factors are expressed sequentially during the development of anthers in petunia.

The development of anthers and pollen involves several stages. In an attempt to identify the transcription factors that are involved in the regulation of gene expression associated with the development of anthers, seven genes for new zinc-finger proteins that are expressed in anthers were detected using RT-PCR. Subsequent cloning and sequence analysis of the full-length cDNA clones revealed that they all encoded zinc-finger proteins of the EPF type. However, the encoded proteins were very different from each other in terms of size, number of zinc fingers (two, three and four) and the spacings between the fingers. Northern blot analysis revealed that the genes were expressed preferentially in anthers. Moreover, it was found that the seven genes were expressed transiently for short periods that corresponded to different developmental stages. It appeared that the genes were activated sequentially during the development of the anther. Considering these observations, a possible mechanism that could account for the autonomous progression of the development of the anther via a regulatory cascade of these transcription factors is discussed.

Amino Acid Sequence↗
PubMed1998

Enhancement of the tolerance of Arabidopsis to high temperatures by genetic engineering of the synthesis of glycinebetaine.

Arabidopsis thaliana was transformed with the codA gene for choline oxidase from Arthrobacter globiformis under control of the 35S RNA promoter of cauliflower mosaic virus. As a result, high levels of glycinebetaine accumulated in the seeds of transformed plants. Transformation with the codA gene significantly enhanced the tolerance to high temperatures during the imbibition and germination of seeds, as well as during growth of young seedlings. The extent of enhancement of the tolerance to high temperature was correlated with levels of choline oxidase expressed and of glycinebetine accumulated in the transformed plants. The induction of homologues of heat shock protein 70 at high temperature was less conspicuous in the transformed plants than in the wild-type plants, suggesting that the transformation alleviated the high-temperature stress.

Adaptation, Physiological↗
PubMed1998

Cysteine residues in the carboxyl terminal domain of the endothelin-B receptor are required for coupling with G-proteins.

We demonstrate that the human endothelin-B (ETB) receptor incorporates [3H]palmitic acid. Mutation of three putative palmitoylated cysteine residues (amino acids 402, 403 and 405) in the carboxyl terminus into serine residues (C2/3/5S) completely prevented palmitoylation of ETB. When expressed in CHO cells, C2/3/5S was localized on the cell surface, retained high affinity for ET-1 and ET-3, and was rapidly internalized when bound to the ligand. However, unlike the wild-type ETB, C2/3/5S transmitted neither an inhibitory effect on adenylate cyclase nor a stimulatory effect on phospholipase C, indicating a critical role of palmitoylation in the coupling with G-proteins, regardless of the G-protein subtype. Truncation of the carboxyl terminus, including all or a part of the three cysteine residues, gave palmitoylation-negative and -positive deletion mutants, delta 402 and delta 403. Despite the absence of the cytoplasmic tail, both delta 402 and delta 403 showed essentially the same features as C2/3/5S, except that delta 403 did transmit a stimulatory effect on phospholipase C via a pertussis toxin-insensitive G-protein, most likely a member(s) of the Gq family. These results indicated a differential requirement for the carboxyl terminus downstream from the palmitoylation site in the coupling with G-protein subtypes, i.e., it is required for the coupling with Gi but not for that with Gq.

Animals↗
PubMed1998

Semiological seizure classification.

We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.

Electroencephalography↗
PubMed1998

Circumferential spontaneous coronary artery dissection in an elderly man: a case report.

An 82-year-old man developed acute inferior myocardial infarction. Emergent coronary angiography demonstrated thrombotic occlusion in the right coronary artery. Intracoronary thrombolytic therapy was performed with successful recanalization. However, circumferential dissection with luminal stenosis was revealed at the point of thrombus formation. Repeat angiography 6 months later showed resolution of the dissection. This is the first description of circumferential spontaneous coronary artery dissection. In addition, the present patient is older than any previous patients.

Aged↗
PubMed1998

Effect of nasal continuous positive airway pressure on pulmonary edema complicating acute myocardial infarction.

Cardiogenic pulmonary edema is a frequent cause of reparatory failure. We investigated the effects of nasal continuous positive airway pressure (CPAP) in patients with severe pulmonary edema associated with acute myocardial infarction. Twenty-nine consecutive patients were divided into 3 groups: firstly, 7 intubated patients who received mechanical ventilation at study entry comprised the intubation group. The rest of the patients were randomly assigned to either of the following 2 groups: 11 patients who received oxygen plus CPAP delivered by a nasal mask (CPAP group), and 11 patients who received oxygen only via face mask (oxygen group). All patients in the intubation group had cardiogenic shock. Two patients (18%) in the CPAP group and 8 patients (73%) in the oxygen group required mechanical ventilation with endotracheal intubation (p=0.03). The hospital mortality rate in the CPAP group (9%) was significantly lower than the oxygen group (64%, p=0.02). The pulmonary artery wedge pressure and heart rate were significantly lower in the CPAP group than in the oxygen group 24 h after study entry (p<0.05 and p<0.01). The mean pulmonary artery pressure 48 h after study entry was 18+/-5 mmHg in the CPAP group and 25+/-8 mmHg in the oxygen group (p<0.05). The PaO2/FiO2 ratio increased in the intubation group (168+/-69 to 240+/-57, p<0.05) and the CPAP group (137+/-17 to 253+/-67, p<0.01) 24 h after study entry. Arterial plasma endothelin-1 concentrations decreased significantly earlier in the CPAP group than in the oxygen group (p<0.05). In patients without cardiogenic shock, nasal CPAP lead to an early improvement in oxygenation and hemodynamics, and decreased the mortality rate. Early and active respiratory management is recommended in patients with pulmonary edema associated with acute myocardial infarction.

Aged↗
PubMed1998

Pulmonary Nocardia otitidiscaviarum infection in a patient with chronic respiratory infection.

We report a case of pulmonary Nocardia (N.) otitidiscaviarum infection in a 76-year-old man with chronic respiratory infection. The patient responded poorly to intravenous imipenem and oral minocycline, but later improved after treatment with trimethoprim-sulfamethoxazole. Pulmonary infection with N. otitidiscaviarum should be considered in the differential diagnosis of chronic respiratory infections. Further studies are needed to evaluate the correlation between species and drug susceptibility.

Aged↗
PubMed1998

Molecular cloning of Arabidopsis photolyase gene (PHR1) and characterization of its promoter region.

Photolyase is an enzyme that repairs ultraviolet (UV)-damaged DNA by photoreactivation. In higher plants, accumulation of photolyase (PHR1) mRNA is induced by either UV or visible light. In order to know the molecular mechanism by which PHR1 gene expression is induced by light, we have determined the genomic structure and the 5'-flanking sequence of the Arabidopsis PHR1 gene. The PHR1 gene spans approximately 2.5 kb of genomic DNA and consists of 9 exons. In the promoter region of PHR1, there are two pairs of inverted repeats spanning more than sixty base pairs. The promoter also contains DNA motifs similar to the GT-1 box or G-box found in many light-inducible gene promoters. EMSA analysis showed that several proteins in Arabidopsis nuclear extract bound to the G-box-like motifs. These results raise the possibility that the Arabidopsis PHR1 gene is regulated by transcription factors which interact with these motifs.

5' Untranslated Regions↗