Functional mechanism underlying cyclooxygenase-2 expression in rat small intestine following administration of indomethacin: Relation to intestinal hypermotility

Background and Aim:  We recently reported that cyclooxygenase (COX)-2 is upregulated in the rat small intestine after administration of indomethacin, and this may be the key to non-steroidal anti-inflammatory drug (NSAID)-induced intestinal damage. The present study investigated the mechanism for COX-2 expression induced in the rat small intestine by indomethacin, in relation with ulcerogenic processes.
Methods:  Animals were given indomethacin or SC-560 p.o., and the intestinal mucosa was examined 24 h later.
Results:  Indomethacin caused hemorrhagic lesions in the small intestine, accompanied with an increase in intestinal motility, bacterial invasion and inducible nitric oxide synthase (iNOS) activity, as well as the expression of COX-2 mRNA in the mucosa. Although SC-560 did not cause any damage, this agent caused intestinal hypermotility, the bacterial invasion and the upregulation of COX-2 expression. The mucosal PGE₂ content was decreased by SC-560 at 3 h but recovered 12 h later, and this recovery of PGE₂ was attenuated by both atropine and ampicillin, in addition to rofecoxib. The intestinal hypermotility response to indomethacin was prevented by both 16,16-dimethyl PGE₂ and atropine, but not ampicillin. Yet all these agents inhibited not only the bacterial invasion but also the expression of COX-2 and iNOS activity in the intestinal mucosa following indomethacin treatment, resulting in the prevention of intestinal lesions.
Conclusion:  These results suggest that COX-2 expression in the intestinal mucosa following the administration of indomethacin is associated with intestinal hypermotility and bacterial invasion. The intestinal hypermotility caused by COX-1 inhibition may be a key to COX-2 expression after administration of NSAIDs and their intestinal ulcerogenic properties.     

Clinical parameters that predict histology of postchemotherapy retroperitoneal lymph node mass in testicular cancer

BACKGROUND: Since the advent of cisplatin-based chemotherapy, the majority of metastatic testicular cancers can be cured by chemotherapy followed by retroperitoneal lymph node dissection (RPLND). However, postchemotherapy RPLND confers no therapeutic benefit if the residual mass contains no viable cells. Therefore, to determine which parameters predict a patient's likelihood of having only necrosis in the residual mass, we retrospectively analyzed clinical parameters of patients who underwent postchemotherapy RPLND. METHODS: Data from 27 patients with metastatic testicular cancer were analyzed. The histology of the primary tumor was seminoma in 11 cases and non-seminoma in 16 cases. All of the patients with non-seminoma showed a normalization of tumor markers after chemotherapy. Analysis of clinical parameters included data for the initial histology, pretreatment tumor marker levels, postchemotherapy retroperitoneal mass size, and the histology of the dissected RPLNs. RESULTS: Histological examination of dissected RPLNs showed residual tumor in 27% of seminoma patients and 38% of non-seminoma patients. In seminoma patients, no viable cells were found in all six patients with pretreatment lactate dehydrogenase (LDH) levels below 7.5 times the upper limit of normal, or in all five of the patients with postchemotherapy RPLNs less than 2.5 cm. In non-seminoma patients, no viable cells were found in nine of 10 patients with pretreatment alpha-fetoprotein (AFP) levels less than 2700 ng/mL, or in eight of nine patients with residual mass less than 2.5 cm. CONCLUSIONS: Both postchemotherapy RPLN mass size and pretreatment tumor marker levels are possible predictors for necrosis of the residual mass in testicular cancer patients.     

Prevalence of and risk factors for nocturia: Analysis of a health screening program

BACKGROUND: We examined the prevalence of and risk factors for nocturia in Kurashiki city and the surrounding area, a rural area in Japan. MATERIALS AND METHODS: We collected data on 6517 individuals (4568 men and 1949 women) who participated in a multiphasic health screening. We analyzed the relationships between nocturia assessed by a questionnaire (voiding twice or more during night) and other variables including age, hypertension, cardiovascular disease, cerebrovascular disease, chronic obstructive pulmonary disease, diabetes mellitus (DM), chronic renal failure, benign prostatic hyperplasia (BPH), smoking habit and alcohol intake. RESULTS: Overall, 1856 individuals (28.5%) answered that they arose to urinate at least twice during the night. This rate increased with age from 16.5% in individuals younger than 50 to 60.0% in those older than 69. Logistic regression analysis revealed that cohorts of subjects 50-59, 60-69, and 70 years old or over had, respectively, 1.75, 3.35, and 6.21 times the prevalence of nocturia of the 49 years or younger cohort. Hypertension (odds ratio [OR] 1.64) and DM (OR 1.70) were other independent positive risk factors for nocturia. On the other hand, current smokers who smoked 20 or more cigarettes per day were less likely to have nocturia than non-smokers (OR 0.72). In male individuals, BPH was another independent positive risk factor (OR 1.35). Gender was not associated with nocturia. CONCLUSIONS: Although population bias is an important limitation to this study, nocturia is associated with various factors suggesting that multiple approaches are needed to the treatment of patients with nocturia.     

Effect of surfactant lavage in a rabbit model of meconium aspiration syndrome

Meconium aspiration syndrome (MAS) is a frequent cause of respiratory distress in neonates. Recent reports have suggested that surfactant dysfunction contributes to the pathophysiology of MAS and surfactant therapy improves oxygenation of infants with MAS. We evaluated the effect of bronchial lavage with surfactant solution in a rabbit model of meconium aspiration. All animals were given 5 mL/kg of a 20% slurry of human meconium into the endotracheal tube and mechanically ventilated. The animals were then divided into saline lavage (n = 5) or surfactant lavage (n = 5). Lavage was performed an hour after meconium instillation. After the lavage the total amount of meconium recovered was measured. Blood gas was monitored during the experiment. The amount of meconium recovered by saline lavage was 14%, and by surfactant lavage was 57%. The surfactant group had a significant improvement in gas exchange, whereas the saline group had no improvement. It was concluded that the lavage with surfactant solution effectively washed out meconium and improved gas exchange in rabbit model of MAS.     

Experimental Assessment of Right Ventricular Function in Normal Pigs with a Left Ventricular Assist Device

Abstract: Right ventricular (RV) failure during the use of a left ventricular assist device (LVAD) is the leading cause of death in circulatory support patients. Previous work, both experimentally and clinically, has shown the difficulties in predicting the behavior of the right ventricle at the start of LVAD. An experimental study has been designed to evaluate RV functional changes during LVAD and its relation to preload changes. The model used adult mongrel pigs (n = 10). Right ventricular functional parameters were measured with a thermodilution RV ejection fraction catheter. The left ventricle was supported by a Nippon Zeon blood pump. Two groups were studied, the first one was the LVAD–off group (n = 5) and the other was the LVAD–on group (n = 5) which was supported by LVAD at maximum flow. Change of cardiac output, mean pulmonary artery pressure (PAP), RV stroke work, and RV ejection fraction in both groups were not significantly different. However, the relationship between right ventricular end–diastolic pressure (RV–EDP) and right ventricular stroke volume (RVSV) was significantly changed at a high level of RV–EDP. When RV–EDP was over 6. 5 mm Hg in the LVAD–off group, RVSV decreased to 52. 3 ± 11. 5 ml while in the LVAD–on group, RVSV increased to 97. 2 ± 22. 0 ml. The change in PAP in the LVAD–on group was lower than in the LVAD–off group. We conclude that, at the volume overload state, LVAD can reduce the afterload of the right ventricle and maintain Frank–Starling's effect, thus having a beneficial effect on right ventricular performance.     

No effects of large doses of catecholamines on vascular permeability in isolated blood-perfused dog lungs

Neurogenic pulmonary oedema (NPO) is believed to be induced by intense activation of the sympathetic nervous system, characterized by massive secretion of catecholamines into the blood stream. There is a possibility that NPO is partly the result of increased vascular permeability. However, the mechanism for an increase in pulmonary vascular permeability is not known. The present study was designed to test the hypothesis that large doses of catecholamines increase pulmonary microvascular permeability directly. Adrenaline or noradrenaline (100 and 300 pug) was injected as a bolus into isolated dog lungs perfused with heparinized autologous blood at constant pressure. Adrenaline or noradrenaline produced sustained lung weight loss although both catecholamines increased pulmonary capillary pressure, assessed by double occlusion pressure, by 2–5 mmHg above baseline. Vascular permeability, as measured by the capillary filtration coefficient and the isogravimetric capillary pressure, did not change significantly frombaseline at 30 and 60 min after catecholamine. Finally, the final-to-initial wet lung weight ratio of the catecholamine-treated lungs did not differ from that of saline-injected control lungs. Thus, we conclude that circulating catecholamines, even at supra-physiological doses, do not increase vascular permeability in isolated blood-perfused dog lungs.     

The Preclinical Safety Evaluation of Human Monoclonal Antibody against Cytomegalovirus

The human monoclonal antibody against cytomegalovinis (Mab C23)was examined pharmacokinetically and toxicologically as partof the preclinical studies prior to approval for human use.Rats given repeated intravenous administrations of Mab C23 producedno antibodies against Mab C23 and maintained a blood Mab C23level in a dose-dependent manner. However, pregnant rabbitsproduced antibodies against Mab C23. The half-life of Mab C23in plasma was 15.9 days in rats, which was similar to that ofnormal human serum -globulin (NHSG). Neither behavioral effectsnor circulatory disturbance was found in mice, rats, and dogseven after a single intravenous injection of 100 or 200 mg/kg,which corresponds to 50 or 100 times the intended clinical dosage.The repeated doses of 2, 10, or 20 mg/kg of Mab C23 on six occasionswith 1- or 2-week intervals elicited a transient decrease inleukocyte counts in rats given 10 or 20 mg/kg, but no adverseeffects in cynomolgus monkeys. Mab C23 did not cause any reproductiveor developmental toxicity when administered to rats and rabbitsat dose levels of 20 mg/kg or less. However, pregnant animalsshowed lower plasma levels of Mab C23 than non-pregnant animals.The chromosomal aberration test disclosed no clastogenicityin human lymphocytes. An immunostaining for Mab C23 revealedno localizations in several tissues of cynomolgus monkeys givenintravenous doses of Mab C23. The preclinical safety evaluationin animals other than rabbits, which produced no antibodiesagainst Mab C23, showed that the behavior of Mab C23 is pharmacokineticallysimilar to that of NHSG and is as safe as NHSG, which has longbeen used as a biological agent. However, because there wasa difference in blood levels of Mab C23 between pregnant andnonpregnant animals, its clinical administration to pregnantpatients should differ from that to non-pregnant patients.     

Infectious mononucleosis in Japan: Comparison with acute viral hepatitis type A

In order to clarify the characteristics of infectious mononucleosis hepatitis (IMH) in Japan, 20 cases with IMH treated at Kamo Hospital during the past 6 years (Group I) were analysed in comparison with cases of acute viral hepatitis, especially type A. The test for heterophil antibody was positive in only two cases. During the same period 209 cases were treated for acute viral hepatitis (type A: 77 cases = Group A; type B: 61 cases; type non-A, non-B: 71 cases). In Group I the common clinical symptoms and signs were headache, sore throat and lymph node swelling; jaundice was not as common as in Group A. GOT and GPT activities increased moderately in the acute stage, but they were significantly lower than those in Group A. LDH, AP, GGT and LAP activities were disproportionately higher to GPT activity in Group I. Liver biopsy in the convalescent stage showed that lipofuscin deposition and sinusoidal mononuclear cell infiltration were more prominent in Group I, while sinusoidal neutrocyte infiltration and focal necrosis at periportal areas were more common in Group A. Differential diagnosis of the two diseases could be made using these clinical features and histological findings. However, immunological differentiation is required for specific diagnosis because some features such as fever, prolonged elevation of thymol turbidity test, atypical lymphocytes in peripheral blod and predilection for young people were observed in both groups. Furthermore, the present study indicated that IMH is no longer rare and most cases do not demonstrate heterophil antibody in Japan.