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Biomedical subjects

N Hamada

Publications and source records attributed to N Hamada.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Studies of intraoperative plateletapheresis in cardiovascular surgery].

We evaluated the effect of intraoperative plateletapheresis (IPA) on platelet dysfunction associated with cardiopulmonary (C-P) bypass in 49 patients for open heart or great vessel surgery. Autologous platelet concentrated (PC) (16.6 +/- 6.1 units) was collected before the start of C-P bypass and was reinfused after protamine administration. Platelet aggregability after PC reinfusion was significantly greater in IPA group (n = 13) than in non-IPA group (n = 15). Platelet count and ionized calcium level were lower in the IPA group temporarily after PC collection. No differences were noted in hemodynamic variables, WBC count and hemoglobin between the two groups. Plasma IL-6, which increased slightly after PC collection, showed a great increase after C-P bypass in both IPA (n = 8) and non-IPA (n = 8) groups. In in vitro experiments, platelet aggregability was reduced with the increase of centrifugal force over 800 x g during PC separation (n = 10) and with the prolongation of PC preserving time over 4 hours (n = 11). The result of this study demonstrates the significance of plateletapheresis in post-bypass platelet function and hemostasis, although further improvements are needed for collection and preservation of PC.

Aged↗
PubMed2000

Purification and characterization of a novel secondary fimbrial protein from Porphyromonas gingivalis strain 381.

We previously reported the existence of two different kinds of fimbriae expressed by Porphyromonas gingivalis ATCC 33277. In this study, we isolated and characterized a secondary fimbrial protein from strain FPG41, a fimA-inactivated mutant of P. gingivalis 381. FPG41 was constructed by a homologous recombination technique using a mobilizable suicide vector, and failed to express the long fimbriae (41-kDa fimbriae) that were produced on the cell surface of P. gingivalis 381. However, short fimbrial structures were observed on the cell surface of FPG41 by electron microscopy. The fimbrial protein was purified from FPG41 by DEAE-Sepharose CL-6B column chromatography. The secondary fimbrial protein was eluted at 0.15 M NaCl, and the molecular mass of this protein was approximately 53 kDa as estimated by SDS-PAGE. An antibody against the 53-kDa fimbrial protein reacted with the short fimbriae of the FPG41 and the wild-type strain. However, the 41-kDa long fimbriae of the wild-type strain and the 67-kDa fimbriae of ATCC 33277 did not react with the same antibody. Moreover, the N-terminal amino acid sequence of the 53-kDa fimbrial protein showed only 2 of 15 residues that were identical to those of the 41-kDa fimbrial protein. These results show that the properties of the 53-kDa fimbriae are different from those of the 67-kDa fimbriae of ATCC 33277 as well as those of the 41-kDa fimbriae.

Amino Acid Sequence↗
PubMed2000

Inhibition of influenza virus replication in cultured cells by RNA-cleaving DNA enzyme.

Influenza virus replication has been effectively inhibited by antisense phosphothioate oligonucleotides targeting the AUG initiation codon of PB2 mRNA. We designed RNA-cleaving DNA enzymes from 10-23 catalytic motif to target PB2-AUG initiation codon and measured their RNA-cleaving activity in vitro. Although the RNA-cleaving activity was not optimal under physiological conditions, DNA enzymes inhibited viral replication in cultured cells more effectively than antisense phosphothioate oligonucleotides. Our data indicated that DNA enzymes could be useful for the control of viral infection.

Animals↗
PubMed2000

Abdominal multivisceral transplantation in pigs.

We investigated the technical aspects of porcine abdominal multivisceral transplantation, in terms of pathophysiological features in animals given no immunosuppresant. The splanchnic organs of the donor animal were flushed in situ with University of Wisconsin solution via the abdominal aorta, using a pump. After a relatively short period of cold storage in saline, multivisceral grafts, including the liver, pancreas, and gastrointestinal tract, were transplanted orthotopically. Of the 18 recipient pigs that underwent the operation, 9 (50%) died within 24 h, mainly because of respiratory insufficiency (n = 5) and circulatory shock (n = 3). Three animals (17%) were lost to acute renal failure between the second and fifth postoperative days. Six pigs (33%) survived for more than 1 week, and the causes of death in these animals were bowel obstruction (n = 1), pneumonia (n = 2), rejection of the intestinal graft (n = 2), and deterioration (n = 1). Although the results of this study were not satisfactory, abdominal multivisceral transplantation using pigs is practical and may lead to the possible resolution of various problems, in regard to the immunologic aspects and the interrelationship of transplanted complex organs.

Animals↗
PubMed2000

Multiple duodeno-jejunal diverticula causing massive intestinal bleeding.

A case of massive intestinal blood loss from multiple duodeno-jejunal diverticula is described. A 39-year-old man was referred to our hospital because of recurrent bloody stool and worsening anemia. Upper and lower endoscopy, selective abdominal angiography, and radionuclide scanning were performed to seek the cause of the intestinal bleeding, but none of these studies revealed the source of bleeding. Small-bowel barium follow-through examination showed numerous diverticula in the distal duodenum and proximal jejunum. Excision of the duodenal diverticulum and resection of the involved portion of the jejunum cured the patient. On histopathological examination, an ulcerative lesion with an exposed vessel suggestive of the source of bleeding was seen in the resected duodenal diverticulum. Although duodeno-jejunal diverticula are rare, the importance of a careful search for this malformation in a patient with intestinal blood loss is stressed.

Adult↗
PubMed2000

Stress responses during laparoscopy with CO2 insufflation and with mechanical elevation of the abdominal wall.

STUDY OBJECTIVE: To compare the intensity of stress responses caused by laparoscopy combined with CO2 insufflation (CI) with those caused by mechanical elevation of the abdominal wall (MEA). DESIGN: Prospective study (Canadian Task Force classification I). SETTING: Tertiary care university hospital. PATIENTS: Thirty-one women. Intervention. Laparoscopy, 16 with CI and 15 with MEA. MEASUREMENTS AND MAIN RESULTS: Circulating levels of norepinephrine, epinephrine, cortisol, and interleukin (IL)-6 were compared in the two groups. Arterial partial pressure of CO2 (PaCO2) did not increase during laparoscopy by either method. Plasma norepinephrine and epinephrine levels increased after extubation in the MEA group but not in the CI group. Circulating cortisol levels in both groups increased during laparoscopy; mean intraoperative levels were higher in the CI group. Serum IL-6 levels increased after extubation in the MEA but not the CI group. Mean heart rate increased during laparoscopy in both groups, whereas blood pressure increased only in the CI group. More patients in the MEA group required postoperative analgesia. CONCLUSION: Laparoscopy with MEA caused more pronounced adrenosympathetic and cytokine responses than that with CI when PaCO2 was maintained within the range of normocapnia.

Carbon Dioxide↗
PubMed2000

Thyroid-stimulating antibody is related to Graves' ophthalmopathy, but thyrotropin-binding inhibitor immunoglobulin is related to hyperthyroidism in patients with Graves' disease.

We investigated the relationship between thyroid function or ophthalmopathy of Graves' disease and thyrotropin receptor antibodies (TRAb) in 155 untreated patients with Graves' hyperthyroidism. All patients were examined by ophthalmologists, and underwent computed tomography of the orbit and measurement of serum free triiodothyronine (FT3), free thyroxine (FT4), thyrotropin-binding inhibitor immunoglobulin (TBII), and thyroid stimulating antibodies (TSAb). Patients were divided into three groups according to the presence of orbital fat increase (OFI) and extraocular muscle enlargement (EME): 57 patients without OFI and EMO formed the no Graves' ophthalmopathy (NGO) group; 55 patients with OFI but without EMO formed the OF group; 43 patients with EME with or without OFI formed the EM group. The FT3, FT4, and thyroid weight increased in the order of the EME, NGO, and OFI groups. TSAb increased in the order of the NGO, OFI, and EME groups, and TSAb was significantly greater in the EME and OFI than in the NGO group. TBII was not significantly different among the three groups, but was lower in EME than NGO. There was a significant positive correlation between TBII and FT3 or FT4 in all patients combined as well as in all three groups, but correlation between TSAb and FT3 or FT4 was very weak in all groups, and that between TSAb and FT3 was not significant in the EM group In the relationship between ophthalmopathy and TRAb, the sum of the scores of eyelid swelling, proptosis, and extraocular muscle enlargement was taken as a measure of the overall severity of the Graves' ophthalmopathy (GO). TSAb was significantly correlated with the GO score, but there was no correlation between TBII and GO scores. In conclusion, TSAb was correlated with ophthalmopathy but TBII was related to hyperthyroidism.

Adipose Tissue↗
PubMed2000

Presence of two trans-o-hydroxybenzylidenepyruvate hydratase-aldolases in naphthalenesulfonate-assimilating Sphingomonas paucimobilis TA-2: comparison of some properties.

Two trans-o-hydroxybenzylidenepyruvate hydratase-aldolases named tHBP HA A and tHBP HA B were purified from a cell-free extract of naphthalenesulfonate-assimilating Sphingomonas paucimobilis (formerly Pseudomonas sp.) TA-2 to an electrophoretically homogeneous state by successive column chromatographies on DEAE-cellulose, DEAE-Toyopearl 650M, Sephacryl S-100, Hydroxyapatite, and Mono Q. These enzymes were similar to each other in molecular mass (ca. 37 kDa on SDS-PAGE, ca. 110 kDa on ultracentrifugation), thermal stability (<50 degrees C) and optimum pH (pH 9.0). However, they differed from each other in N-terminal amino acid sequences, pH stability, K(m) values for trans-o-hydroxybenzylidenepyruvate (tHBP), and inhibition by p-chloromercuribenzoic acid (PCMB). tHBP HA B had a homologous N-terminal amino acid sequence with tHBP HAs from Pseudomonas vesicularis DSM 6383 (strain BN6) and Sphingomonas aromaticivorans F119, and tHBP HA A had a homologous sequence with tHBP HAs of Pseudomonas putida strain OUS82, Pseudomonas sp. strain C18 and NAH7 plasmid. tHBP HA B was inhibited by PCMB, but tHBP HA A was not. Their K(m) values for tHBP were 9 and 3 M, respectively. tHBP HA B was stable in the range of pH 7.1 to pH 10.7, and tHBP HA A was stable in the range of pH 6.0 to 9.3.

Amino Acid Sequence↗
PubMed2000

Sequential changes of arterial oxygen tension in the supine position during one-lung ventilation.

UNLABELLED: To investigate how surgical positions affect the severity and progress of hypoxemia during one-lung ventilation (OLV), we studied 33 adult patients undergoing right thoracotomy with left OLV. The patients were divided into three groups according to the positions during surgery as follows: the supine position (SP) group (n = 11), the left semilateral decubitus position (LSD) group (n = 9), and the left lateral decubitus position (LLD) group (n = 13). Analysis of arterial blood gases was sequentially determined every 5 min for 30 min during OLV (fractional ratio of inspiratory oxygen = 1.0) in each position. OLV was promptly terminated and switched to bi-lung ventilation if Spo2 declined to 90%. Pao2 progressively decreased with time in all three groups (P < 0.01). The incidence of termination of OLV within 30 min was higher in the SP group (82%), compared with that in the LSD (11%) and LLD (8%) groups (P < 0.01). Final Pao2 (65+/-12 mm Hg, mean +/- SD, P < 0.01 versus LLD, P < 0.05 versus LSD) and SaO2 (91%+/-4%, P < 0.01 versus LLD and LSD) at the termination of OLV in the SP group were the lowest. There was no difference between these values in the LSD and LLD groups (128+/-54 mm Hg, 96%+/-2%, and 167+/-69 mm Hg, 97%+/-4%, respectively) 30 min after the start of OLV. The time for Pao2 to decrease to 200 mm Hg calculated from each regression curve was 354 s in the SP group, 583 s in the LSD group, and 798 s in the LLD group. The time for Pao2 to decline to 100 mm Hg was 794 s in the SP group. In the regression curves of the LSD and LLD groups, the Pao2 did not decrease to 100 mm Hg. Heart rate was slow at baseline in the SP group (P < 0.05 versus LSD), but other hemodynamic variables did not differ among the three groups throughout this study. The LSD was as effective as the LLD in avoiding life-threatening hypoxemia during OLV. IMPLICATIONS: Close observation and prompt counteractions including termination of one-lung ventilation (OLV) are crucial for patients under OLV in the supine position, because life-threatening hypoxemia frequently occurs approximately 10 min after starting OLV, even under 100% oxygen inhalation. The left semilateral decubitus position was as effective as the left lateral decubitus position in avoiding life-threatening hypoxemia during OLV.

Blood Gas Analysis↗
PubMed2000

Ascorbic acid stimulation of production of a highly branched ,beta-1,3-glucan by Aureobasidium pullulans K-1--oxalic acid, a metabolite of ascorbic acid as the stimulating substance.

The production of a highly branched beta-1,3-glucan by Aureobasidium pullulans K-1 in Czapek's medium has been found to be stimulated by ascorbic acid. When the culture supernatant, after removal of polysaccharide from the culture filtrate by ethanol precipitation, was concentrated, then added to a new medium and this strain was cultured in the medium, the polysaccharide production was stimulated the same as when L-ascorbic acid was added to the medium. The stimulating substance was partially purified from the supernatant, and was found to be oxalic acid; 0.03% oxalic acid was the most effective concentration for the stimulation of polysaccharide production. The stimulating substance, oxalic acid, was proved to be derived from ascorbic acid added to a medium in an experiment using L-[1-14C]ascorbic acid. We suggest that oxalic acid generated from the metabolism of ascorbic acid in cells of Aureobasidium pullulans K-1 participated in the stimulation of the polysaccharide production by ascorbic acid.

Ascorbic Acid↗
PubMed2000

Sympathetic overactivity in the development of eyelid retraction in a patient with euthyroid Graves' disease evaluated by accommodation.

It is known that measurement of accommodation is useful to evaluate the sympathetic activity of intraocular muscles. To find if sympathetic overactivity is involved in eyelid retraction in euthyroid Graves' disease, we measured accommodation in two patients with this disease, whose serum concentrations of free T3, free T4 and TSH were within reference ranges. Accommodation was measured with a computer-assisted infrared optometer with an iriscoder, and the results were expressed as the change in the eye's refractive power (in diopters) in response to the movement of a target beam. In patient 1, the accommodation amplitude was low, indicating sympathetic overactivity. This amplitude rose to near the reference range when timolol maleate drops were used, and the eyelid retraction disappeared when guanethidine drops were given. During the use of guanethidine drops, accommodation remained normal. In patient 2, who had normal accommodation, eyelid retraction did not change with guanethidine administration, but improved with intravenous methylprednisolone pulse therapy. These two cases suggested that even in euthyroid Graves' disease, eyelid retraction is caused by sympathetic overactivity, and pulse therapy with methylprednisolone may be effective for eyelid retraction when guanethidine drops are not effective.

Accommodation, Ocular↗
PubMed2000

Melatonin secretion from organ-cultured pineal glands of rats: modulation by gonadectomy and gonadotropin-releasing hormone agonist administration.

The objective of the study was to evaluate the effect of pretreatments such as gonadectomy in male and female rats, and gonadotropin-releasing hormone agonist (GnRHa) administration in female rats, on levels of secretion of melatonin, using an organ culture of pineal glands. Gonadectomy 2 weeks before the animal was killed increased the amount of melatonin secreted into the medium by the pineal glands of female rats but not of male rats. The increase in in vitro melatonin secretion after ovariectomy in female rats was prevented by estrogen replacement. Ovariectomy 3 and 4 weeks before death also significantly increased the amount of melatonin secretion. Administration of GnRHa 2 weeks before decapitation significantly decreased serum estradiol concentrations and significantly increased melatonin secretion by the pineal glands of female rat. GnRHa administration 3 or 4 weeks before decapitation also significantly decreased serum estradiol concentrations, but did not increase pineal secretion of melatonin. The results indicate that ovariectomy increases melatonin secretion from organ-cultured pineal glands and that this increase is suppressed by estrogen in adult female rats. In contrast, orchiectomy in male rats does not influence in vitro secretion of melatonin. These results suggest that the GnRH-gonadotropin system may participate in the regulation of pineal melatonin secretion in adult female rats.

Animals↗
PubMed2000

Toxoplasmic encephalitis in patients with acquired immunodeficiency syndrome--four case reports.

Four patients, all males aged 40-64 years, presented with toxoplasmic encephalitis associated with human immunodeficiency virus (HIV) infection manifesting as nonspecific neurological deficits such as epilepsy or hemiparesis. Magnetic resonance imaging showed single or multiple lesions with ring enhancement, mimicking metastatic brain tumor or brain abscess. Marked eosinophilia was noted in three patients. Two patients who received anti-toxoplasma chemotherapy in the early stage had a good outcome. However, the other two patients suffered rapid neurological deterioration and needed decompressive surgery, resulting in a poor outcome. Toxoplasma diffusely infects the whole central nervous system from the early stage. The outcome for patients who needed emergency surgery was poor. Therefore, this rare but increasingly common infectious disease must be considered in the differential diagnosis of a patient with neuroimaging findings similar to those of metastatic tumor or brain abscess. Appropriate chemotherapy should be started immediately after HIV-positive reaction is identified in patients with single or multiple mass lesions with ring enhancement.

AIDS Serodiagnosis↗
PubMed2000

Toremifene-induced fatty liver and NASH in breast cancer patients with breast-conservation treatment.

We have described fatty liver, diagnosed by computed tomography scanning (CT) in more than 30% of patients with breast cancer who received tamoxifen. Therefore, it is urgent to elucidate the frequency and the degree of fatty liver induced by toremifene, an analogue of tamoxifen, which is also used in breast cancer. We enrolled 52 breast cancer patients who were treated with breast-conservation treatment and administered oral toremifene for 3-5 years as adjuvant endocrine therapy. We evaluated the degree of fatty liver by abdominal CT performed annually. CT demonstrated toremifene-induced fatty liver in four (7.7%) of 52 breast cancer patients. Toremifene-induced fatty liver did not correlate with abnormal levels of AST, ALT, GGT or total cholesterol. One patient who demonstrated moderate fatty liver by CT was histologically diagnosed as non-alcoholic steatohepatitis (NASH) by liver biopsy. The incidence of toremifene-induced fatty liver was significantly lower than that induced by tamoxifen. Accordingly, in terms of fatty liver and NASH, toremifene is considered to be more appropriate agent than tamoxifen. Though toremifene is less likely to induce fatty liver, the possibility remains that toremifene-induced steatohepatitis occurs. Because the diagnosis of fatty liver or NASH can be easily missed if only a blood test is performed, it is necessary to screen fatty liver by annual CT examination for patients who receive an antiestrogen agent.

Alanine Transaminase↗
PubMed2000

[Intraoperative hemodilutional autotransfusion using a closed circuit for patients of Jehovah's Witness].

We conducted hemodilutional autotransfusion using a closed circuit combined with a cell washing reinfusing system (Cell Saver) for two surgical patients of Jehovah's Witness. One was a 12 yr-old boy for extirpation of the teratoma in the anterior mediastinum and another was a 44 yr-old woman for left total hip replacement. The patients and their relatives had consented to the use of blood substitutes, hemodilutional autotransfusion using a closed circuit and Cell Saver. We devised a closed circuit system for hemodilutional autotransfusion combined with Cell Saver, in which two pumps for blood transfusion were used; one was for drawing blood from the femoral or the internal jugular vein and the other for returning blood to the peripheral vein. Blood volume in a bag interposed in the closed circuit was easily controlled by adjusting the speed of each pump. Blood collected from the surgical field by Cell Saver was also led to the bag. Acid citrate dextrose solution was infused into the closed circuit from the site close to the blood drawing. Both of our surgical patients were safely managed without homologus blood transfusion, although there remained some problems concerning the use of anticoagulants.

Adult↗