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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 379 records · Page 21Linked to original sources
PubMed1996

Rheumatoid arthritis associated with ulcerative colitis.

This report describes a 58-year-old man with rheumatoid arthritis (RA) and interstitial pneumonia who suffered from low-grade fever, abdominal pain, and bloody diarrhea 16 months after the diagnosis of RA. Ulcerative colitis (UC) was diagnosed, based on endoscopic and histological findings. RA associated with UC is rare and the underlying mechanism is unknown. We discuss here whether vasculitis and HLA class may play some role in the association of RA with UC.

Arthritis, Rheumatoid↗
PubMed1996

Subcapsular hematoma of the liver and pylethrombosis in the setting of cholestatic liver injury.

We describe a subcapsular hematoma of the liver and pylethrombosis in a patient who developed cholestasis 4 days after severe burn injury. On the 44th hospital day, severe anemia suddenly appeared with no determinable cause. This was the initial manifestation of hepatic hematoma. Cholestatic liver injury of unknown cause lasted throughout the clinical course. The patient subsequently died of hepatic failure 27 months after the burn injury. An autopsy confirmed pylephlebitis and pylethrombosis, which were considered to have contributed to the hepatic failure. This was a rare case of hepatic hematoma and pylephlebitis and pylethrombosis that developed after burn injury.

Aged↗
PubMed1996

Interleukin-6 secreted from human myxoma reduces murine viral myocarditis.

The effect of interleukin-6 (IL-6) secreted by a human atrial myxoma in vitro was investigated in C3H female mice with acute viral myocarditis. A culture medium containing IL-6 (100 ng/ml) and IL-8 (250 ng/ml), was prepared; viral myocarditis was induced by exposure to the encephalomyocarditis virus. Mice were assigned to four groups: 1) intraperitoneal (i.p.) injection of supernatant with IL-6 and IL-8 (0.2 ml/mice) given simultaneously with virus, 500 pfu for 4 days (Group 1); 2) i.p. injection of supernatant with IL-6 starting on Day 4 for 4 days in the same manner (Group 2); 3) i.p. injection of culture medium simultaneously with the virus (Group 3); and 4) i.p. injection of PBS in the same manner (Group 4). Uninfected control mice were administered medium only (Group 5) or supernatant with IL-6 and IL-8 (Group 6) for 4 days without virus. The survival rate on Day 14 in Group 1 was 90% significantly (p < 0.01) prolonged. The ratio of heart weight-to-day weight in the Group 1 was significantly (p < 0.01) lower. Histopathological examination revealed that cardiac necrosis and cellular infiltration in Group 1 was reduced compared with Group 3. Moreover, the radio of spleen weight/body weight in Group 1 was significantly (p < 0.01) higher than that of Group 3 and of Group 4. To confirm the effect of IL-6 or IL-8, mice were treated with recombinant IL-6 to IL-8 simultaneously with virus for 4 days. IL-6 treated mice survived significantly compared with IL-8 treated mice and untreated mice. The viral titer on day 4 of IL-6 treated mice was significantly lower than IL-8 treated or untreated mice. Thus, IL-6 derived from human myxoma improved the survival of murime viral myocarditis and reduced myocardial necrosis when the myxoma-derived IL-6 was administered simultaneously with the virus, due to eliciting cellular immunity in the spleen.

Animals↗
PubMed1996

Recovery of macromolecular activators of phagocytosis from platelets (MAPP) producing and releasing function in stored human platelets.

Macromolecular activators of phagocytosis from platelets (MAPP) were not released from platelets prepared from platelet concentrates (PC) obtained after anticoagulation with CPD solution and stored for more than 48 h. The MAPP activity which had escaped into the plasma disappeared after 72 h of storage. After incubation in dialyzed and Ca(2+)-supplemented plasma prepared from the same PC or from fresh peripheral blood, the platelets obtained after storage for 72 h released both MAPP (l-MAPP and s-MAPP) upon thrombin stimulation. Gel filtration studies of the plasma revealed that l-MAPP and s-MAPP were produced from the platelets incubated in plasma fractions corresponding to l-MAPP and s-MAPP, respectively. These observations suggest that platelets accumulate precursors of MAPP, pre-MAPP comprising pre-l-MAPP and pre-s-MAPP, in the presence of Ca2+, and produce and release MAPP when stimulated with thrombin.

Biological Factors↗
PubMed1996

Oxygenation in fetal lambs supported by extrauterine right atrium to artery extracorporeal membrane oxygenation.

OBJECTIVE: Our purpose was to determine the adequacy of oxygenation, particularly cranial and cardiac oxygenation, in exteriorized fetal lambs on right atrium to artery extracorporeal membrane oxygenation. STUDY DESIGN: Thirteen fetal lambs were placed on right atrium to artery extracorporeal membrane oxygenation between the gestational ages of 113 and 133 days. Various PO2 and oxygen saturation (SO2) values were obtained by varying the oxygen concentrations at the oxygenator membrane. Blood gases, pH, and SO2 were observed on samples taken before and after membrane oxygenation from the left ventricle and through the cranial carotid arterial catheter. These were compared with control values obtained before the cessation of umbilical circulation. Fetal coronary oxygenation was represented by left ventricle PO2 and SO2 and cranial oxygen by carotid artery PO2 and SO2. RESULTS: We classified oxygen saturation as low, medium, and high on the basis of the level of postmembrane SO2. Carotid artery cranial oxygenation in the low SO2 group was equivalent to control values, but that in the medium and high SO2 groups was significantly higher than in the control group. Left ventricle oxygenation was consistently lower than cranial oxygenation in any SO2 group. In the low group left ventricle oxygenation was significantly lower than the control values. CONCLUSIONS: Right atrium to artery extracorporeal membrane oxygenation appears sufficient to oxygenate the fetal cranial circulation but may be inadequate for the efficient distribution of oxygenated blood into the left ventricle and thus the coronary circulation.

Animals↗
PubMed1996

Ultrasound biomicroscopic analysis of transient shallow anterior chamber in Vogt-Koyanagi-Harada syndrome.

PURPOSE: To evaluate the mechanism of formation of the transient shallow anterior chamber in Vogt-Koyanagi-Harada syndrome. METHODS: Two patients with Vogt-Koyanagi-Harada syndrome with shallow anterior chambers were examined with an ultrasound biomicroscope. RESULTS: A ciliochoroidal detachment, which was not obvious on ophthalmoscopic examination, was clearly demonstrated in both patients by ultra-sound biomicroscopy. The detachment disappeared after systemic corticosteroid therapy. CONCLUSION: The shallowing of the anterior chamber in two patients with Vogt-Koyanagi-Harada syndrome was caused by suprachoroidal effusion secondary to inflammation of the uvea.

Anterior Chamber↗
PubMed1996

Serum levels of soluble interleukin-2 receptor in patients with perennial allergic rhinitis before and after immunotherapy.

BACKGROUND: Interleukin-2 receptor (IL-2R) exists in soluble form in sera, and the rate of release of the soluble form of IL-2R (soluble IL-2R) reflects T cell activation in vivo. Since T lymphocytes play a central role in respiratory allergic disorders, the measurement of serum levels of soluble IL-2R may be useful in analyzing the disease state of allergic disorders. OBJECTIVE: To investigate the serum concentrations of soluble IL-2R in 48 patients with perennial allergic rhinitis and 14 nonatopic healthy controls, with special reference to the possible changes following long-term immunotherapy. METHODS: This retrospective study included 48 patients who had had variable periods of long-term immunotherapy with Dermatophagoides farinae extracts. The duration of immunotherapy ranged from 5 to 15 years. Serum samples were collected twice from each patient, before the initiation of immunotherapy and at the time of clinical assessment of immunotherapy. All the serum samples were simultaneously used for determination of soluble IL-2R concentrations, by the use of an enzyme-linked immunosorbent assay. To serve as controls, 14 nonallergic subjects of the same age range and sex were chosen. RESULTS: Patients with allergic rhinitis before immunotherapy had significantly higher serum levels of soluble IL-2R than nonatopic subjects. Elevated serum levels of soluble IL-2R decreased significantly following immunotherapy and the serum levels of soluble IL-2R in patients with allergic rhinitis after immunotherapy were not statistically different from those of nonatopic subjects. In addition, the percent decrease in serum soluble IL-2R correlated significantly with the duration of immunotherapy. CONCLUSIONS: Hyperactivity of helper T cells of atopic patients is altered after long-term immunotherapy, and such immunoregulatory changes could be theoretically involved in the mechanisms of immunotherapy.

Adolescent↗
PubMed1996

Serum level of interleukin-4 in patients with perennial allergic rhinitis during allergen-specific immunotherapy.

Interleukin-4 (IL-4) may play a central role in the IgE synthesis system, the development of Th-2-like cells, and co-ordination as well as the persistence of airway inflammatory process in allergic disorders. Therefore, IL-4 plays a key role in airway allergic disorders. This study aimed at investigating the serum concentrations of IL-4 in patients with perennial allergic rhinitis, with special reference to the possible changes and the clinical relevance following long-term immunotherapy. The study has demonstrated that the serum level of IL-4 in allergic rhinitis patients before immunotherapy is significantly higher than that in non-atopic individuals. However, the serum IL-4 level in allergic rhinitis patients did not decrease following anti-allergic medications but significantly decreased following immunotherapy. The percentage decrease in IL-4 was correlated significantly with the percentage decrease in specific IgE antibodies following long-term immunotherapy. Immunotherapy also significantly decreased specific IgE anti-bodies, but this reduction in specific IgE antibodies was not significantly correlated with the clinical improvement. In contrast, the percentage decrease in serum IL-4 was significantly correlated with the percentage decrease in symptomatic scores. The authors interpret these data to mean that immunotherapy alters T-cell cytokine profiles in the long-term, and a decline of IL-4 following immunotherapy could modulate not only production of specific IgE antibodies but also inflammatory cellular events, leading to symptomatic relief in allergic rhinitis.

Adolescent↗
PubMed1996

Accumulation of p53 and expression of CD44 in human prostatic cancer and benign prostatic hyperplasia: an immunohistochemical study.

OBJECTIVE: To investigate the expression of mutant p53 and wild-type CD44 in human benign and neoplastic prostate. PATIENTS AND METHODS: The accumulation of p53 and the expression of CD44 were investigated immunohistochemically in formalin-fixed and paraffin-embedded tissue specimens (obtained by transurethral resection and open prostatectomy) from 16 patients with primary prostatic cancer (median age 65 years, range 54-75) and six patients with benign prostatic hyperplasia (BPH) (median age 67 years, range 58-75). RESULTS: Positive immunoreactivity for p53 and CD44 was detected in six and eight samples of prostatic cancer tissue, respectively. Additionally, all six prostatic cancer samples showing positive immunoreactivity for p53 were also positive for CD44. There were more samples expressing p53 and CD44 in prostatic cancer with a high Gleason grade score than in samples from cancer with a lower score. In samples from six patients with BPH, positive immunoreactivity for p53 and CD44 was observed in one and two, respectively; stained cells were restricted to the secretory cell layer of the gland. CONCLUSIONS: There was an association between prostatic tumour grade and the increasing expression of p53 and CD44, although there were too few samples for statistical significance. The staining pattern of cells expressing p53 and CD44 may be different between prostatic cancer and BPH tissues.

Aged↗
PubMed1996

Regulation of the gene Sex-lethal: a comparative analysis of Drosophila melanogaster and Drosophila subobscura.

The Drosophila gene Sex-lethal (Sxl) controls the processes of sex determination and dosage compensation. A Drosophila subobscura genomic fragment containing all the exons and the late and early promotors in the Sxl gene of D. melanogaster was isolated. Early Sxl expression in D. subobscura seems to be controlled at the transcriptional level, possibly by the X:A signal. In the region upstream of the early Sxl transcription initiation site are two conserved regions suggested to be involved in the early activation of Sxl. Late Sxl expression in D. subobscura produces four transcripts in adult females and males. In males, the transcripts have an additional exon which contains three translational stop codons so that a truncated, presumably nonfunctional Sxl protein is produced. The Sxl pre-mRNA of D. subobscura lacks the poly-U sequence presented at the polypirimidine tract of the 3' splice site of the male-specific exon present in D. melanogaster. Introns 2 and 3 contain the Sxl-binding poly-U stretches, whose localization in intron 2 varies but in intron 3 is conserved. The Sxl protein is fully conserved at the amino acid level in both species.

Amino Acid Sequence↗
PubMed1996

The epsilon-(gamma-glutamyl)lysine moiety in crosslinked casein is an available source of lysine for rats.

To determine bioavailability, expressed as the protein efficiency ratio (PER) and biological value (BV) in rats, of the epsilon-(gamma-glutamyl)lysine [epsilon-(gamma-Glu)Lys] moiety in crosslinked proteins, we prepared heavily crosslinked [21.5 /micromol epsilon-(gamma-Glu)Lys/g casein] and intermediately crosslinked [13.6 micromol epsilon-(gamma-Glu)Lys/g casein] casein, using microbial transglutaminase. In Experiment 1, rats were assigned to one of four diets (heavily or intermediately crosslinked caseins, intact casein or non-protein diet) for 4 wk to evaluate the bioavailability of the epsilon-(gamma-Glu)Lys moiety in crosslinked casein as the sole source of dietary protein. Rats that were fed intact casein and the two crosslinked caseins had similar growth rates, PER, and BV, indicating that crosslinked caseins supported the growth of rats similarly to the intact casein. In Experiment 2, heavily crosslinked casein was added to wheat gluten-based diets in concentrations of 20 and 40 g/kg diet to evaluate the bioavailability of lysine in the epsilon-(gamma-Glu)Lys moiety of the casein as a lysine supplement for lysine-poor gluten. One of six diets (heavily crosslinked or intact casein diets in the two concentrations, gluten diet, or non-protein diet) was fed to rats for 4 wk. No significant differences in food intake, body weight gain, PER or BV were observed among rats fed the intact or crosslinked casein diets at either 2 or 4 g/100 g casein. These results suggest that the epsilon-(gamma-Glu)Lys moiety in crosslinked caseins are absorbed and therefore supplement the gluten. HPLC analysis of urine and feces of rats fed the crosslinked caseins actually confirmed that approximately 99% of the epsilon-(gamma-Glu)Lys moiety was absorbed in the body.

Animals↗
PubMed1996

Protein-RNA and protein-protein interactions of the Drosophila sex-lethal mediated by its RNA-binding domains.

The Drosophila Sex-lethal (Sxl) contains two RNA-binding domains (RBDs) which belong to the RNA recognition motif (RRM) group. Sxl binds to a specific uridine-rich sequence which is believed to be the major cis-acting element for the splicing regulation of the transformer (tra) mRNA precursor. Here we show evidence supporting the previous suggestion that Sxl recognizes the sequence context downstream of the uridine-rich sequence. In addition, by means of UV-crosslinking assays with Sxl deletion constructs, we have demonstrated that Sxl RNA binding requires both of its RBDs for specificity and strength. Moreover, by the yeast two-hybrid analysis, we found that homodimeric interaction occurs between two Sxl molecules. Interestingly, the amino- and carboxy-terminal regions outside of the Sxl RBDs are dispensable for such dimerization, indicating that the protein-protein interaction is also mediated by RBDs. Coprecipitation experiments in vitro showed that the protein-protein interaction seems to be RNA-dependent but greatly enhanced by addition of the specific RNA containing the Sxl binding site, suggesting that the conformational change which is induced on binding to RNA may facilitate the interaction between Sxl molecules.

Animals↗
PubMed1996

Chemical synthesis of phosphorylated peptides of the carboxy-terminal domain of human p53 by a segment condensation method.

A segment condensation method was developed for the chemical synthesis of large (> 90 amino acid) phosphopeptides and was used to produce phosphorylated and non-phosphorylated derivatives of the C-terminal tetramerization and regulatory domains of human p53 (residues 303-393). Efficient condensation synthesis of the 91 residue p53 domain was achieved in two steps. The non-phosphorylated N-terminal segment p53(303-334) (1) and its derivative phosphorylated at serine 315 (1P315), and the non-phosphorylated middle segment p53(335-360) (2), were synthesized as partially protected peptide thioesters in the solid phase using Boc chemistry. The C-terminal segment p53(361-393) (3) and its derivative phosphorylated at serine 392 (3P392) were synthesized as partially protected peptides in the solid phase using Fmoc chemistry. Phosphoamino acid was incorporated into the N-terminal segment (1P315) at the residue corresponding to p53 serine 315 as Boc-Ser(PO3(Bzl)2)-OH during synthesis. Serine 392 in the C-terminal segment was selectively phosphorylated after synthesis by phosphitylation followed by oxidation. A derivative phosphorylated at serine 378 was synthesized in a one-step condensation of the unphosphorylated N-terminal segment (1) and the phosphorylated long C-terminal segment p53(335-393) (2-3P378). Yields of the ligated peptides after removal of the protecting groups and HPLC purification averaged 60% for the first condensation and 35% for the second condensation. All five p53 peptides exhibited monomer-tetramer association as determined by analytical ultracentrifugation. Circular dichroism spectroscopy revealed that phosphorylation at Ser315 increased the alpha-helical content, which was abolished when Ser392 also was phosphorylated, suggesting an interaction between N-terminal and C-terminal residues of the C-terminal domain of p53.

Amino Acid Sequence↗
PubMed1996

Conformational changes induced in the protein tyrosine kinase p72syk by tyrosine phosphorylation or by binding of phosphorylated immunoreceptor tyrosine-based activation motif peptides.

A critical event in signaling in immune cells is the interaction of Syk or ZAP-70 protein tyrosine kinases with multisubunit receptors that contain an approximately 18-amino-acid domain called the immunoreceptor tyrosine-based activation motif (ITAM). Tyrosine-phosphorylated Syk from activated cells was in a conformation different from that in nonstimulated cells as demonstrated by changes in immunoreactivity. The addition of tyrosine-diphosphorylated ITAM peptides resulted in a similar conformational change in Syk from nonactivated cells. The peptides based on FcepsilonRIgamma were more active than those based on Fcepsilon RIbeta. In vitro autophosphorylation of Syk was dramatically enhanced by the addition of the diphosphorylated ITAM peptides. The conformational change and the enhanced autophosphorylation required the presence of both phosphorylated tyrosines on the same molecule. These conformational changes in Syk by tyrosine phosphorylation or binding to diphosphorylated ITAM could be critical for Syk activation and downstream propagation of intracellular signals.

Amino Acid Sequence↗
PubMed1996

Rate of nitric oxide release in the lung and factors influencing the concentration of exhaled nitric oxide.

The level of nitric oxide (NO) in exhaled air fluctuates in normal individuals depending on the physiological conditions. We evaluated the effects of duration of exhalation and breath-holding on the exhaled concentrations of NO in 16 normal human volunteers. Exhaled gas corresponding to vital capacity was collected in 6-liter Tedlar bags and analyzed by chemiluminescence. The NO concentration in exhaled gas increased significantly in proportion to the duration of exhalation [P = 0.009 +/- 0.011 (SD)] and was increased after breath-holding. There was no significant difference in the exhaled NO concentration among 10-s phases of a 30-s exhalation, as determined from multiple breath collections. The NO released from the airways is presumably unaffected by fluctuation of exhalation speed. The NO release rate, calculated from a single regression analysis between the NO concentration and the duration of exhalation, was 39 +/- 29 pmol/s, a value which was about fourfold greater in nine patients with bronchial asthma.

Adult↗
PubMed1996

An anatomical analysis of the relationships between the intercostal nerves and the thoracic and abdominal muscles in man. I. Ramification of the intercostal nerves.

Minute dissection was performed on the ventral primary rami of the first thoracic to first lumbar nerves in two halves of an adult male cadaver in order to determine points of origins of muscular branches from the intercostal nerves. Generally, the muscular branches originated independently, but the branches supplying the intercostalis intimus and internus tended to originate as a common trunk. The muscular branching patterns were compiled in an illustration, and based on these patterns the serial homology of the thoracic and abdominal muscles was proposed. Although the obliquus externus abdominis has been thought to correspond to the intercostales externi, from these innervation findings it appears to correspond to the intercostales interni. Further, the quadratus lumborum seems homologous to the intercostales externi.

Anatomy, Comparative↗