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Biomedical subjects

H Wada

Publications and source records attributed to H Wada.

At least 1,243 records · Page 69Linked to original sources
PubMedDate not supplied

Effects of cold preservation on the lung mechanical properties in rats.

In lung transplantation, cold preservation is an important process. However, the mechanical changes in the airway and tissue during cold preservation, especially before reperfusion, are unknown. To test the hypothesis that the mechanical changes in the airway and lung parenchyma start during cold preservation, we investigated the mechanical properties of the rat lung as a whole organ and in excised lung strips. In the 0 h group, the lungs were not preserved. In the 9 and 24 h group, the lungs were preserved for 9 and 24 h at 4 degrees C. After preservation, we evaluated the static compliance (Csta) of the whole lung as obtained from the pressure volume curves (n=5 in each group). Also, we measured the input impedance taken by a computer-controlled small-animal ventilator (n=9 in each group). All data were analyzed using a homogeneous linear model, which includes airway resistance (Raw), tissue elastance (H), and tissue resistance (G). Hysteresivity (eta) was calculated as G/H. Moreover, the tissue elasticity (Eqs) obtained from the quasi-static stress-strain curves was compared. There was no significant difference in Csta among the three groups. Raw was significantly lower in the 24 h group than in the 0 h group (p<0.01). Eqs was significantly higher in the preserved groups than in the 0 h group (p<0.01). These results demonstrated that the changes in the three mechanical properties of the airway and the tissue started within 9 h of preservation.

Animals↗
PubMedDate not supplied

Mild hypothermia ameliorates lung ischemia reperfusion injury in an ex vivo rat lung model.

BACKGROUND: Ischemia reperfusion (I-R) injury of the lung frequently occurs after cardiopulmonary bypass, pulmonary thromboendarterectomy, lung transplantation, and major pulmonary resection with vascular reconstruction. Mild hypothermia ameliorates ischemia reperfusion injury of the brain and the liver. However, the effect of mild hypothermia on I-R injury of the lung has not been investigated. METHODS: The lungs of Lewis rats underwent 80 min of ischemia followed by 60 min of reperfusion in an ex vivo perfusion model. The ambient temperature was maintained at either normothermia (38 degrees C, n=6) or mild hypothermia (35 degrees C, n=6) during the ischemia and reperfusion. RESULTS: Pulmonary shunt fraction, peak inspiratory pressure, mean pulmonary arterial pressure during reperfusion, and the wet/dry weight ratio of the lung tissue at the end of reperfusion in the mild hypothermia group were significantly (p<0.05) lower than those in the normothermia group. Total adenine nucleotide, adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate after reperfusion in the mild hypothermia group were significantly (p<0.05) higher than those in the normothermia group. CONCLUSION: Mild hypothermia attenuates I-R injury of the lung with maintained levels of intrapulmonary high-energy phosphate compounds after reperfusion, suggesting its beneficial effect on warm lung I-R in clinical settings.

Adenine Nucleotides↗
PubMedDate not supplied

Plasma norepinephrine and dietary sodium intake in normal subjects and patients with essential hypertension.

To evaluate the relationship between sodium intake and the activity of the sympathetic nervous system in patients with essential hypertension, plasma catecholamine levels were measured in 49 essential hypertensive patients and 38 age-matched normal subjects under regular-, high-, and low-sodium diets (mean 24-hour sodium excretions; 116 +/- 8, 267 +/- 29, 31 +/- 7 mEq/day, respectively). The levels of plasma norepinephrine were significantly (p less than 0.01) higher in hypertensive patients than in normal subjects. However, they were significantly reduced by high-sodium intake and increased by low-sodium intake in both patients and controls. The percent decrease and change in the absolute plasma norepinephrine levels from low- to high-sodium states were greater in normal subjects than in the hypertensive patients. The results are interpreted as indicating that an abnormal relationship exists between sodium intake and the activity of sympathetic nervous system in patients with essential hypertension.

Adult↗
PubMedDate not supplied

Increased plasma norepinephrine in young patients with essential hypertension under three sodium intakes.

Increased sympathetic nerve activity may play an important role in the pathogenesis of essential hypertension. It is well known that both dietary sodium intake and age influence the plasma norepinephrine (NE) concentration. The present study was undertaken to evaluate the effects of age on sympathetic nerve activity in patients with essential hypertension and normal control subjects under low-, regular-, and high-sodium regimens (mean 24-hour sodium excretions: 30 +/- 4, 116 +/- 7,280 +/- 15 mEq, respectively). Plasma NE and epinephrine (E) were analyzed by trihydroxyindole methods after high-performance liquid chromatography separation. Subjects were categorized by age into young (less than or equal to 40 yrs), middle-aged (40-60 years), and old (greater than or equal to 60 years) subgroups. Mean plasma NE in hypertensive patients was significantly higher (p less than 0.01) than in normal subjects on each of the sodium regimens. In normal control subjects, there was a significant positive correlation between age and plasma NE with all three sodium intakes. However, no correlation was seen in hypertensive patients on any of the sodium regimens, because in the young subgroup of hypertensive patients the mean plasma NE was significantly higher than that of normal control subjects. These results suggest that the increased sympathetic nerve activity plays an important role in the pathogenesis of essential hypertension, especially in young patients.

Adult↗
PubMedDate not supplied

Distribution of the carbohydrate antigens, DU-PAN-2 and CA19-9, in tumors of the lung.

AIMS AND BACKGROUND: The carbohydrate chains of malignant cells appear to be related to oncofetal differentiation. The serum levels of CA19-9 have been reported to be evaluated in some patients with lung carcinomas, however, the distribution of carbohydrate antigens were not precisely described. We have investigated in this study the distribution of DU-PAN-2 and CA19-9 antigens in lung tumors. METHODS: Ninety five specimens of lung tumors were selected from surgical specimens. The expression of DU-PAN-2 and CA19-9 were studied by immunohystochemical techniques. The relationship between the expression of these antigens and the classification or the differentiation degree of the tumors were examined. RESULTS: DU-PAN-2 or CA19-9 antigens were detected in 41 (54%) and 45 (59%) cases of the 76 malignant epithelial tumors investigated. These antigens were detected in all types of malignant epithelial tumors, including squamous cell carcinomas, where they were mainly localized to the entire cell surface of malignant cells. In adenocarcinomas, large cell carcinomas and small cell carcinomas, however, these antigens were commonly detected both on the cell membrane and in the cytoplasm. There was positive correlation between the degree of differentiation and DU-PAN-2, but not CA19-9 expression. Among the non-epithelial tumors investigated, those antigens were detected in pulmonary blastomas but not in mesotheliomas. CONCLUSIONS: Immunohistochemical studies for DU-PAN-2 and CA19-9 are useful for defining characteristics of the lung tumors. DU-PAN-2 could be a marker for differentiating between malignant epithelial tumors and mesotheliomas.

Adenocarcinoma↗
PubMedDate not supplied

Disseminated mycobacterial infection in a hemophilia B patient with acquired immunodeficiency syndrome.

Disseminated mycobacterial infection was found at autopsy in a male patient with hemophilia B and acquired immunodeficiency syndrome (AIDS). In May 1986, 23 months before death, the patient had encephalitis for one month and in July he developed a fever, malaise and generalized lymphoadenopathy. Human immunosuppressive virus (HIV) was positive and the CD 4/8 ratio of lymphocyte surface markers was 0.1, but mycobacterium was not detected. In September 1986, he had severe dyspnea due to interstitial pneumonia and he was treated with high-dose methylprednisolone. He died after a 23-month course of fever, severe weight loss and terminal progressive deterioration, although he was treated with antibiotics, antifungal agents, gamma-globulin, steroid and a Azidothymidine.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Phylogenetic position of the dicyemid mesozoa inferred from 18S rDNA sequences.

The dicyemid mesozoa, obligate symbionts in the cephalopod kidney, are simply organized multicellular animals. They have long been the subject of phylogenetic debates. Some authors have suggested that dicyemids represent an offshoot from an early metazoan ancestor. Other workers considered them to be degenerated progeny of higher metazoa, possibly parasitic trematodes. We determined the almost complete nucleotide sequences of 18S rDNA in two species of dicyemid, Dicyema orientale and Dicyema acuticephalum, isolated purely from cephalopod urine. We compared these sequences with sequences determined in the present study from three flatworm species, as well as with a variety of eukaryote sequences obtained from databases. The phylogenetic trees reconstructed with the use of the neighbor-joining, maximum-parsimony, and maximum-likelihood methods indicated that the dicyemids belong among the triploblastic animals (Bilateria). However, we cannot firmly establish the position of the dicyemids within the Bilateria because we cannot ignore the problem of long branch attraction between the myxozoans, dicyemids, nematodes, and acoel flatworms. The present results favor the hypothesis that the dicyemids do not represent an early divergent metazoan group, but rather a group degenerated from a triploblastic ancestor.

Animals↗
PubMedDate not supplied

Histaminergic mechanism of motion sickness. Neurochemical and neuropharmacological studies in rats.

Rats were rotated about two parallel axes to produce motion sickness, and the histamine levels in their hypothalamus and pons-medulla oblongata were measured. Rotation for 60 min induced kaolin intake, which is a behavioral index of motion sickness in rats, and increased the histamine levels in the hypothalamus and pons-medulla oblongata, the highest levels occurring after 15 min of rotation. In bilaterally labyrinthectomized rats, no rise in histamine level was observed. alpha-Fluoromethylhistidine (alpha-FMH), which depletes the neural component of histamine in the brain, suppressed kaolin intake induced by rotation. These findings demonstrated that the histaminergic neuron system contributes to development of motion sickness, and suggested that alpha-FMH may be effective as an anti-motion sickness drug.

Animals↗
PubMedDate not supplied

Effects of anti-cholinergic and cholinergic drugs on habituation to motion in rats.

The effects of the anti-cholinergic drug scopolamine, an anti-motion sickness drug, and of the cholinergics physostigmine and neostigmine on habituation to motion sickness in rats were examined using pica, measured as eating of kaolin, as a behavioural index of motion sickness in rats. Rats were rotated around two axes for 1 h once a day for 10 or 11 days. Rotation-induced kaolin intake of control rats gradually decreased from day 9 of daily rotation. Test rats were not treated for the first 3 days, given drugs on days 4-7 of rotation and then again given no drugs for the next 3 or 4 days. Rotation-induced kaolin intake of test rats was compared to that of controls. Results showed that TTS (Transdermal Therapeutic System)-scopolamine administration facilitated habituation to rotation, whereas physostigmine, a centrally acting cholinesterase inhibitor, suppressed it, and neostigmine, a peripherally active cholinesterase inhibitor, had no effect on habituation at all. These findings suggest that the central cholinergic neuron system plays an important role in the neural mechanism of habituation to motion in rats.

Animals↗
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Relationship between evoked otoacoustic emissions and middle-ear dynamic characteristics.

Evoked otoacoustic emissions (EOAEs) are considered to originate from outer hair cell movement and to be transmitted to the external auditory meatus through the ossicular chain and eardrum in a retrograde fashion. Therefore, the effect of the middle ear on EOAEs seems to be large. A sweep frequency middle-ear analyzer (MEA) has been developed that gives much more information on middle-ear dynamic characteristics than a conventional impedance meter. In this paper, applying our own EOAE measuring system and the MEA, EOAEs and middle-ear dynamic characteristics of normal subjects were measured, and an attempt was made to clarify the relationship between EOAEs and middle-ear dynamic characteristics. It is concluded that EOAEs are detected most distinctly at the middle-ear resonance frequency and that EOAEs are most detectable in normal subjects whose middle-ear mobility is moderate.

Acoustic Stimulation↗
PubMedDate not supplied

Effect of middle ear on otoacoustic emissions.

Otoacoustic emissions (OAEs) are believed to originate from outer hair cell movement and are considered to be transmitted to the external auditory meatus through the middle ear in a retrograde fashion. Therefore, the effect of the middle-ear on OAEs seems to be large. However, few investigations of middle-ear effects on OAEs have been published because no apparatus that can measure the middle-ear dynamic characteristics is easily available except a conventional impedance meter. We developed a sweep frequency impedance meter (SFI) which gives us much more information on middle-ear dynamic characteristics than a conventional impedance meter. In this paper, applying SFI and 3 OAE measuring apparatuses, middle-ear dynamic characteristics and different sorts of OAEs of human subjects and guinea pigs were measured, and an attempt was made to examine the relationship between OAEs and middle-ear dynamic characteristics from various aspects. It is concluded that frequency characteristics of OAEs correlate well with middle-ear frequency characteristics; and middle-ear effect on OAEs must be taken into account when OAE data are analyzed.

Acoustic Stimulation↗
PubMedDate not supplied

Scrotal ulcer occurring in patients with acute promyelocytic leukemia during treatment with all-trans retinoic acid.

Although all-trans retinoic acid (ATRA) has been shown to improve the outcome of patients with acute promyelocytic leukemia (APL) compared with chemotherapy alone, various adverse effects have been reported. We report here the development of scrotal ulcer in four patients with APL during ATRA treatment. ATRA 45 mg/m2 was administered orally to four patients with newly diagnosed APL, two of whom also received chemotherapy. Scrotal ulcers appeared in all four patients after a median of 22 days (range: 17-29 days) of ATRA treatment. ATRA was discontinued in only one patient, who was then treated with methylprednisolone pulse therapy. The fever resolved, and scrotal ulcer improved after this treatment. The other three patients were treated with steroid or antibiotic ointment for scrotal ulcers. ATRA was re-administered 2 years later in one patient who had relapse of APL. Ulcers appeared again on the scrotal and lower abdominal skin on day 27 of ATRA treatment. These findings strongly suggest that scrotal ulcer is a potential adverse effect of ATRA.

Abdomen↗
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The therapeutic strategies in performing emergency surgery for gastroduodenal ulcer perforation in 130 patients over 70 years of age.

BACKGROUND/AIMS: Gastroduodenal ulcer is a very common illness in Japan. As the number of elderly persons in Japan increases the same as in Europe and America, the number of such patients requiring a gastroduodenal emergency operation has also increased. Regarding the complications of peptic ulcer, a perforation remains the most important fatal complication. The aim of this study is to investigate the operative risk factors and the long-term recurrence rates and to define the optimal surgical procedures in emergency situations in elderly patients. METHODOLOGY: From April 1988 through March 1997, 130 patients over 70 years of age with a perforated gastroduodenal ulcer (a duodenal ulcer perforation in 50 patients and a gastric ulcer perforation in 80 patients) were operated on in an emergency situation in our clinic. We investigated the following items; medical illness, preoperative risk factor, optimal surgical procedure, postoperative organ failure and the cumulative recurrence-free rates after surgical treatment. RESULTS: A significant correlation with mortality was observed in patients with established comorbidity in the following organs: lung (P = 0.03), heart (P = 0.02), kidney (P = 0.04), and diabetes (P = 0.03). The highest postoperative mortality rate was recorded in patients who underwent a simple closure of a duodenal ulcer perforation (4 patients; 26.7%), while the lowest postoperative mortality rate was recorded in patients who underwent a simple closure and vagotomy of a duodenal ulcer perforation (3 patients; 12.5%). In gastric ulcers, the mortality rate in patients with a gastrectomy was significantly higher than in patients with a simple closure. The practical application of the three risk factors (preoperative shock, delay to surgery over 24 hours, and medical illness) was shown by the progressive rise in the mortality rate with the increasing number of risk factors. Based on the 5 postoperative years after treating a perforated duodenal ulcer, the cumulative recurrence rate after a simple closure (63.6%) was significantly higher than that after a simple closure and vagotomy (38.1%) (n = 0.02) or after gastrectomy (0%) (P < 0.001). At 5 years postoperatively, the cumulative recurrence rate after a simple closure (41.2%) was significantly higher than that after a gastrectomy (15.9%) (P < 0.01). CONCLUSIONS: In conclusion, in an emergency situation, elderly patients are in a highly unfavorable prognostic condition due to their advanced age, and comorbidity, which thus leads to poorer results, not only worldwide, but also in Japan. Based on our findings, in duodenal ulcer cases, a simple closure and vagotomy is recommended because of its low mortality and minimal stress, except for cases with a giant perforation measuring over 20 mm in diameter at the perforation hole or with severe duodenal stenosis. In stomach ulcer cases, a gastrectomy may be recommended because of its low recurrence rate.

Age Factors↗
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Hypercoagulable state in patients with hypercholesterolemia: effects of pravastatin.

Molecular markers of the coagulation system and the effects of pravastatin on lipid levels and the coagulation markers were studied in 48 patients (mean age, 55 years) with hypercholesterolemia (plasma total cholesterol levels > 280 mg/dl). Each patient received 10 mg of pravastatin daily for 3 months. Plasma total cholesterol and low-density lipoprotein cholesterol levels decreased significantly during treatment and high-density lipoprotein cholesterol levels increased significantly. Above-normal plasma levels of thrombin-antithrombin III complex, fibrinopeptide A, FDP-D-dimer, plasminogen activator inhibitor-I, and thrombomodulin were found in the patients before treatment; each of these was reduced significantly during treatment. The findings suggest the presence of a hypercoagulable state in hypercholesterolemia and that pravastatin might prevent the hypercoagulable state by reducing hypercholesterolemia.

Adult↗
PubMedDate not supplied

Cholinergic influence of K(+)-evoked release of endogenous histamine from rat hypothalamic slices in vitro.

The effects of cholinergic agents on the K(+)-evoked release of endogenous histamine from hypothalamic slices of rats were examined by a superfusion method in vitro. Acetylcholine and carbamylcholine significantly inhibited K(+)-evoked release of histamine from the slices, and the effect of acetylcholine was antagonized by the muscarinic antagonist atropine. On the other hand, nicotine significantly enhanced the K(+)-evoked release and its effect was antagonized by the nicotinic antagonist hexamethonium. The effects of carbamylcholine and nicotine on histamine release from slices of whole hypothalamus and from slices of the anterior hypothalamic region, which do not contain cell bodies of the histaminergic neurons, were the same. Thus, the K(+)-evoked release of endogenous histamine from histaminergic fibers in the hypothalamic slices was inhibited by muscarinic agents and enhanced by nicotinic agents. These results suggest that muscarinic and nicotinic receptors exert antagonistic effects on the release of hypothalamic histamine from in vitro slice preparations. The cholinergic receptors modulating histamine release might be located presynaptically on the histaminergic terminals.

Animals↗
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Over-tube is preferable to free-hand technique to avoid recurrence of varices after endoscopic injection sclerotherapy. Prospective randomized trial.

One hundred and two patients undergoing sclerotherapy of esophageal varices, using 5% ethanolamine oleate, were randomly allocated to either the over-tube (O-T) or the free-hand (F-H) group, and 100 patients could be followed at monthly intervals for a period of 30.8 +/- 14.7 months (mean +/- SD) after the varices had been eradicated. Endoscopy performed one month after the final session of sclerotherapy revealed circumferential ulcers and scarring in the lower esophagus in 42 of 50 patients (84%) in the O-T group and in 16 of 50 patients (32%) of the F-H group, the difference being statistically significant (P less than 0.01). In the remaining 8 and 34 patients in the O-T and the F-H groups, respectively, a partly fibrotic residual mucosa was seen. There was a recurrence of the varices in the residual mucosa in 14 (28%) in the F-H group during the mean follow-up period of 25.6 months, while there were five patients (10%) with a recurrence of varices in the O-T group, the difference being statistically significant (P less than 0.05). The survival rates showed no statistical significance. Two patients in the F-H group had recurrent bleeding. We conclude that the over-tube technique of sclerosing esophageal varices reduces the rate of recurrence of the varices, in the long term follow-up, and after formation of a circumferential scarring in the lower esophagus.

Esophageal and Gastric Varices↗