VDR and NRAMP1 gene polymorphisms in susceptibility to pulmonary tuberculosis among the Chinese Han population: a case-control study

OBJECTIVE

To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population.

DESIGN

In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods.

RESULTS

Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4.

CONCLUSIONS

Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.

[Effects of CS-866, an angiotensin II receptor antagonist, in 5/6 nephrectomized spontaneously hypertensive rats]

To assess the chronic antihypertensive and renal protective effects of the specific angiotensin II receptor antagonist, CS-866, in the remnant kidney model of chronic renal failure, we administered it alone or in combination with temocapril, an angiotensin converting enzyme inhibitor, to 5/6 nephrectomized spontaneously hypertensive rats (SHR) for 8 weeks. At the age of 10 weeks, 5/6 nephrectomized SHR were allocated to receive two doses of CS-866 (CS-3; 3 mg/kg/day, or CS-10; 10 mg/kg/day), temocapril (TEM; 10 mg/kg/day), a combination of CS-866 (3 mg/kg/day) and temocapril (10 mg/kg/day) or the vehicle alone via oral gavage for 8 weeks. Systolic blood pressure (SBP) and urinary protein excretion (UprotV) were measured every two weeks. At the age of 18 weeks, the rats were decapitated and the blood, remnant kidney, aorta and heart were collected and used for biochemical measurements and histopathological studies. There was no significant difference in body weight among the groups during the study. All drug treatments significantly reduced SBP, UprotV, glomerular sclerosis index (GSI), relative interstitial volume (RIV) and the heart weight to body weight ratio. The hypotensive effects were in the order of combination therapy > CS-10 = TEM > CS-3. For correlational analysis, we used values for SBP and UprotV derived from the average of values in rats over the age of 12 weeks through 18 weeks. UprotV, GSI and RIV were found to be highly correlated with SBP among the individual rats pooled from all groups (r = 0.511, r = 0.754, r = 0.817, respectively) and the correlation was maintained among the group means (r = 0.945, r = 0.989, r = 0.918, respectively). Furthermore, the heart weight to body weight ratio was found to be highly correlated with SBP among the individual rats pooled from all groups (r = 0.923) and the correlation was maintained among the group means (r = 0.996). We conclude that organ protective effects of CS-866, TEM, or combination therapy are closely related to the magnitude of their antihypertensive effects.

Renal protective effects of chronic exercise and antihypertensive therapy in hypertensive rats with chronic renal failure

OBJECTIVES

Patients with chronic renal failure are restricted to mild physical activity and tend to a lack of exercise. However, there have been few reports regarding the influence of chronic exercise on the progression of renal disease. Similarly, there are few animal models concerned with the effect of exercise training on improving renal function. Therefore, we assessed the renal effects of moderate chronic treadmill exercise in a remnant kidney model of spontaneously hypertensive rats (SHR) with chronic renal failure. We also assessed the effects of exercise and antihypertensive therapy on renal function.

DESIGN AND METHODS

Eight-week-old SHR were subjected to 5/6 nephrectomy by removal of the left kidney and excision of two-thirds of the right kidney. The rats were divided into four groups: (i) no exercise (Non-EX); (ii) moderate exercise with treadmill running (20 m/min, 0 grade incline for 60 min) (EX); (iii) EX with an angiotensin converting enzyme (ACE) inhibitor, enalapril (2 mg/kg per day, i.p.); and (iv) EX with an angiotensin receptor antagonist, losartan (5 mg/kg per day, i.p.), for 4 weeks.

RESULTS

Chronic EX significantly attenuated the increase in proteinuria (P < 0.01) and significantly protected against increases in the index of glomerular sclerosis (IGS). Both enalapril and losartan with EX significantly decreased blood pressure (P < 0.001), and further decreased the IGS. In the stepwise multiple regression analysis, only antihypertensive drug remained in the model as a significant predictor of IGS (P < 0.0001). In contrast, exercise, antihypertensive drug and mean systolic blood pressure (weeks 1-4) remained in the model as a significant predictors of mean proteinuria (weeks 1-4) (all P < 0.0001).

CONCLUSIONS

These results suggest that exercise does not worsen renal function and has renal-protective effects in this model of rats. Moreover, the antihypertensive therapy has additional renal-protective effects in this model of rats.

Tc1/Tc2 and Th1/Th2 balance in Asian and Western types of multiple sclerosis, HTLV-I-associated myelopathy/tropical spastic paraparesis and hyperIgEaemic myelitis

CD8+ T cells, like CD4+ T cells, can differentiate into at least two subsets with distinct cytokine patterns: Tc1 cells produce Th1-like cytokines and Tc2 cells produce Th2-like cytokines. To clarify the immunopathological roles of Tc1 and Tc2 cells in central nervous system (CNS) inflammation, we examined intracellular cytokines in CD8+ and CD4+ T cells by flow cytometry and analyzed the Tc1/Tc2 balance as well as the Th1/Th2 balance in 80 patients with various CNS inflammatory diseases, including 20 with optico-spinal multiple sclerosis (OS-MS), 21 with conventional MS (C-MS), 22 with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 17 with hyperIgEaemic myelitis. Twenty-two healthy subjects were also examined as controls. Patients with OS-MS showed a significantly higher percentage of INF-gamma+IL-4- CD8+ T cells as well as CD4+ T cells and a significantly higher intracellular interferon-gamma (IFN-gamma)/interleukin-4 (IL-4) ratio both in CD8+ and CD4+ T cells throughout the relapse and remission phases than the healthy controls. Furthermore, the patients with OS-MS showed a significantly lower percentage of INF-gamma-IL-4+ CD4+ T cells as well as CD8+ T cells during the relapse phase than the healthy controls. On the other hand, the patients with C-MS showed a significantly higher percentage of IFN-gamma-IL-4+ CD8+ T cells in addition to more IFN-gamma+IL-4- CD4+ T cells during the relapse phase than the healthy controls. The HAM/TSP patients showed a significantly higher percentage of INF-gamma+IL-4- CD8+ T cells and a significantly higher intracellular IFN-gamma/IL-4 ratio in CD8+ T cells than the healthy controls. In contrast, in hyperIgEaemic myelitis, in addition to a significantly lower intracellular IFN-gamma/IL-4 ratio in CD4+ T cells, a tendency toward a lower intracellular IFN-gamma/IL-4 ratio in CD8+ T cells in comparison to the healthy controls was observed. These results clarified for the first time the distinct Tc1/Tc2 balance in each disease condition as follows: Tc1 cell response is predominant in OS-MS and HAM/TSP, while Tc2 cell response is predominant in hyperIgEaemic myelitis and at relapse phase of C-MS. Furthermore, our results suggest that CD8+ T cells play an adjunctive role in disease induction and the clinical course of MS.

Effects of troglitazone and temocapril in spontaneously hypertensive rats with chronic renal failure

OBJECTIVE

The insulin resistance state is common in humans and animals with chronic renal failure. We investigated the effects of troglitazone, an insulin sensitizer, on blood pressure and nephropathy in the remnant kidney model of spontaneously hypertensive rats (SHR).

METHODS

Eight-week-old male SHR were subjected to five-sixth nephrectomy. At the age of 10 weeks, the rats were randomly allocated to groups that received troglitazone (70 mg/kg per day); the angiotensin converting enzyme inhibitor temocapril (10 mg/kg per day); troglitazone (70 mg/kg per day) plus temocapril (10 mg/kg per day), or a vehicle alone as an untreated control group. Systolic blood pressure (SBP) and urinary protein excretion were measured every 2 weeks. At the age of 22 weeks, biochemical measurements and histological examination were performed.

RESULTS

Blood glucose, glycosylated hemoglobin and body weight were similar in the four groups. SBP, serum creatinine and glomerular sclerosis index were significantly reduced in all treated groups compared with those in the control group. Urinary protein excretion, glomerular volume and aortic media thickness were significantly decreased in temocapril-treated rats and troglitazone plus temocapril-treated rats compared with those in control rats. Although antihypertensive effects of troglitazone were minute compared with those of temocapril or troglitazone plus temocapril, there was no significant difference between the glomerular sclerosis indices in these three drug-treated groups.

CONCLUSIONS

The results suggest that troglitazone has renoprotective effects in this rat model. These effects might be due to the inhibition of growth factors rather than to the minute hypotensive effect, although the mechanism remains to be elucidated.

[Relation between alkaline phosphatase in gingival crevicular fluid of implant and the curing result]

OBJECTIVE

To investigate the relation between alkaline phosphatase (ALP) in gingival crevicular fluid (GCF) and prognosis.

METHODS

We measured the alkaline phosphatase in gingival crevicular fluid among 56 cases of implant tooth which included 2 failed cases, 5 cases in bad oral hygiene and with gingivitis, compared with the normal group consisted of 10 healthy persons.

RESULTS

The difference of ALP level between normal group and success implant group is not significant, but between normal group and success with gingivitis group is significant(P < 0.05). The ALP level of 2 failed cases are highest (because of few failed cases, no statistics was done).

CONCLUSIONS

The ALP level in GCF is supposed to be an important index in evaluating the result of the implant.

Flow cytometric differentiation of Asian and Western types of multiple sclerosis, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and hyperIgEaemic myelitis by analyses of memory CD4 positive T cell subsets and NK cell subsets

We examined the alterations of memory CD4(+) T cell subsets bearing surface receptors linked to either Th1 or Th2 cytokine production as well as natural killer (NK) cell subsets by three color flow cytometry in the peripheral blood from 36 patients with clinically definite multiple sclerosis (MS), 27 patients with HAM/TSP, 13 patients with hyperIgEaemic myelitis who had mite antigen-specific IgE and 25 healthy controls (HC). The patients with MS were clinically classified into an optico-spinal form of MS (Asian type, MS-A) and the conventional form of MS (Western type, MS-W). MS-A showed a significant increase of CD4(+)CD45RA(-)CCR5(+) cells (Th1 cells) through the relapse and remission phases in comparison to HC, while MS-W showed a significant increase of CD4(+)CD45RO(+)CD62L(-) cells (Th1 cells) only at the relapse phase. HAM/TSP showed a significant increase of CCR5(+) and CD62L(-) memory CD4(+) T cells as well as CD30(+) memory CD4(+) T cells (Th2 cells) in comparison to HC. On the other hand, a selective increase of CD4(+)CD45RO(+)CD30(+) cells was found in hyperIgEaemic myelitis. The percentage of mature NK cells (CD3(-)CD16(+)CD56(+) cells) as well as double negative T cells (CD3(+)CD4(-)CD8(-) cells) decreased significantly in HAM/TSP in comparison to HC. Our findings therefore suggest a flow cytometric analysis of Th1/Th2-associated markers on memory CD4(+) T cells as well as NK cell subsets to be useful for differentiating various inflammatory neurologic conditions.

Renal-protective effect of nondepressor dose of cicletanine in diabetic rats with hypertension

We assessed the renal and cardiac benefits of cicletanine (CIC), a furopyridine derivative drug with diuretic and antihypertensive properties, in diabetic spontaneously hypertensive rats with renal impairment. Uninephrectomized streptozotocin (STZ)-diabetic spontaneously hypertensive Izmo rats (SHRIzm) (10 weeks old) were randomly assigned to receive vehicle or CIC (100 mg/kg/day, orally), and age-matched, uninephrectomized STZ diabetic Wistar-Kyoto Izmo rats (WKYIzm) were assigned to receive vehicle for up to 12 weeks. Blood pressure increased progressively in diabetic SHRIzm but not in diabetic WKYIzm. Urinary albumin excretion increased significantly in both diabetic SHRIzm and diabetic WKYIzm throughout the experiment. The antihypertensive effect of CIC was not significantly observed in diabetic SHRIzm. However, the subdepressor doses of CIC significantly decreased urinary albumin excretion, serum creatinine, and blood urea nitrogen in diabetic SHRIzm. These results were confirmed by morphological analysis of kidneys in each group of rats. The index of focal glomerular sclerosis (FGS) in diabetic SHRIzm was significantly higher than that in diabetic WKYIzm. The CIC treatment significantly and effectively protected against an increase in the index of FGS in diabetic SHRIzm. Moreover, CIC treatment significantly attenuated the increase in the heart weight to body weight ratio in diabetic SHRIzm. Treatment with CIC did not affect urinary and blood glucose concentrations at this dose. These results suggest that CIC has a renal-protective action, which is not related to improvement of diabetes or improvement of high blood pressure in diabetic rats with hypertension. The action might be due to the reduction of intraglomerular capillary pressure or protection of the renal glomerular vascular endothelial cell injury and mesangial cell injury through stimulation of PGI2 generation or elimination of free radicals, although the mechanism remains to be further investigated.

[Experimental investigation on the etiology and pathogenesis of pituitary prolactin-secreting tumor]

Male SD rats transplanted with an extra pituitary in the renal capsule and treated chronically with 17-beta-estradiol (E2) were used in the studies on the pathogenesis and the underlying mechanisms of pituitary prolactin-secreting tumor (prolactinoma). The results indicated that after long treatment with E2, prolactin-secreting tumor was generated in both eutopic and ectopic pituitary, accompanied by hyperprolactinemia and overexpression of PRL gene. No apparent difference was observed in histology and ultrastructure between them. Further investigations showed that some growth factors might be involved in the tumorigenesis of prolactinoma in vivo and in vitro. A point mutation was found in the proximal promoter of PRL gene only in eutopic prolactinoma by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP), suggesting that the base change in the promoter may be related to the overexpression of PRL gene. This hypothesis has been confirmed by the increased activity of luciferase reporter fused to the mutant promoter in vitro. The coincidence of overexpression of PRL, TGF alpha and TGF beta 1 gene, and the point mutation detected in eutopic pituitary prolactinoma suggested that neuro-endocrine-immune interactions in vivo might be associated with pituitary prolactinoma formation. The mechanisms mediating tumorigenesis of eutopic and ectopic prolactinoma, respectively, may be different.

Pituitary prolactin-secreting tumor formation: recent developments

Prolactinoma is the most common type of primary pituitary tumors. It occurs more frequently in women than in men. Dopaminergic agonists are effective in the shrinkage of prolactin-secreting pituitary tumor and are preferred in some patients. However, pituitary radiotherapy may enable the long-term removal of prolactin-secreting tumor cells. Recent evidence suggests that prolactinoma is a heterogeneous disorder with complicated and multifactorial etiology and pathogenesis. Apparently, a thorough understanding of prolactinoma tumorigenesis would be important. To facilitate investigations on tumorigenesis of prolactinoma, animal models for prolactinomas have been developed. These models have expedited our progress in the recent years. Many researchers consider the F(344) rat to be the most sensitive strain of rats to estrogen (E(2))-induced prolactinoma formation. Nonetheless, E(2) treatment for 60 days also induces the formation of pituitary prolactin-secreting adenoma in male Sprague-Dawley (SD) rats. Evidently, the SD rat is also a good animal for prolactinoma investigations. Following E(2) implantation, prolactinomas developed in the eutopic adenohypophysis in situ and/or ectopic pituitary grafted under the renal capsule in SD rats. These observations favor the hypothesis that prolactinoma growth is the result of pathological changes in the adenohypophysis and/or hypothalamus. In the latter case, abnormal release of hypothalamic dopamine, GABA, or brain-gut peptides (such as cholecystokinin, vasoactive intestinal polypeptide, galanin, angiotensin, opioid peptide, gastrin, gastrin-releasing peptide, pancreatic polypeptide, and adrenocorticotropic hormone) results in some of the pathological changes that may lead to hyperprolactinemia and/or prolactinoma development. Dysregulation of prolactin synthesis and secretion may be the result of prolactin gene modulation. In E(2)-induced rat prolactinomas, prolactin mRNA contents and the expression of some proto-oncogenes, e.g. c-myc and c-ras, TGFalpha and TGFbeta1 mRNA were significantly changed. The above findings are consistent with results in human prolactinoma development. In addition, in rats abnormal expression of the prolactin gene was correlated with hypomethylated status of CpG sites in exons 1, 2 and 4 of the prolactin gene, as well as the increase in hypersensitive sites to DNase 1 in the encoding region of the prolactin gene. In E(2)-treated rats, a point mutation with a base substitution from cytidine (C) to adenine (A) was found at the -36-bp site of the proximal promoter of the prolactin gene in eutopic pituitary prolactinomas, but no change was observed in the same sequence of the prolactin gene in ectopic prolactinoma. The association of a base substitution with the hyperexpression of the prolactin gene in eutopic prolactinomas suggests that different mechanisms may mediate the formation of eutopic and ectopic prolactin-secreting tumors. Melatonin decreases the expression of the prolactin gene in vitro suggesting that this pineal hormone may be a potential anticarcinogen in vivo. It has also been shown that MT(2) (Mel(1b)) melatonin receptors are expressed in anterior pituitary cells. The use of melatonin as a preventive or therapeutic drug for prolactinomas should be further investigated. In summary, improved knowledge on tumorigenesis of prolactinomas, especially in the rat model, was noted. These E(2)-induced rat prolactinoma models would facilitate future investigations, and expected results shall be fruitful and exciting for the development of future drug designs for the prevention and/or treatment of prolactin-secreting pituitary tumors.

[Expression of prolactin, TGF alpha and TGF beta 1 genes in estrogen-induced eutopic and ectopic pituitary prolactin-secreting tumors of rats]

The Sprague-Dawley (SD) rat bearing a heteroplasted pituitary underneath renal capsule was used to observe differential expression of prolactin (PRL), transforming growth factor alpha (TGF alpha) and transforming growth factor beta 1 (TGF beta 1) genes during the formation of pituitary prolactin-secreting tumor (prolactinoma) induced by 17 beta-estradiol (E2). Our results indicated that in both eutopic and ectopic pituitaries disconnected from hypothalamus formed simultaneously PRL-secreting tumors after the rats treated with E2 for 120 days in vivo, which was accompanied by overexpression of PRL gene (P < 0.05-0.01). The PRL mRNA level was higher in eutopic prolactinoma than that in ectopic prolactinoma (P < 0.05). Overexpression of TGF alpha and TGF beta 1 genes were also detected in eutopic prolactinoma. However, the expression of TGF alpha and TGF beta 1 genes in ectopic prolactinoma was similar to that in normal pituitary. It is suggested that TGF alpha and TGF beta 1 may be involved in prolactinoma tumorigenesis of eutopic pituitary. However, the mechanism mediating eutopic and ectopic prolactin-secreting tumor formation seems different.

Renal-protective effect of non-depressor dose of cicletanine in streptozotocin diabetic rats

OBJECTIVE

To assess the renal benefits of cicletanine (CIC) in diabetic rats with renal impairment.

METHODS

Hemi-nephrectomized streptozotocin-diabetic Wistar-Kyoto Izmo rats (WKYIzm) (10 weeks old) were randomly assigned to receive vehicle or a low or high dose of CIC (30 or 100 mg/kg per day, orally) for 12 weeks.

RESULTS

The blood pressure was raised slightly but not significantly in this model. An anti-hypertensive effect of CIC was not significantly observed. However, the sub-depressor doses of CIC significantly and dose-dependently decreased urinary albumin excretion. These results were confirmed by morphological analysis of kidneys in each group of rats. CIC treatment significantly and effectively protected against an increase in the percentage of focal glomerular sclerosis. CIC did not affect urinary and blood glucose concentrations at either dose.

CONCLUSIONS

These results suggest that CIC has a renal-protective action, which is not related to improvement of diabetes or of high blood pressure in this model. The action might be due to the reduction of intraglomerular capillary pressure, although the mechanism remains to be further investigated.

[Effects of chronic exercise on renal function in 5/6 nephrectomized spontaneously hypertensive rats (SHR)]

We assessed the renal effects of chronic treadmill exercise in the remnant kidney model of chronic renal failure. Eight-week-old spontaneously hypertensive rats (SHR) were subjected to 5/6 nephrectomy by removal of the left kidney and infarction of two thirds of the right kidney. We performed two series of experiments. Firstly, we investigated the renal effects of chronic mild treadmill exercise in 5/6 nephrectomized SHR. The SHR were divided into 2 groups: a non-exercising group (Non-Ex) and a group conducting mild treadmill running at 20 m/min 0 degree grade for 30 min (Mild-Ex) 5 times/week for 4 weeks. Secondly, we investigated the effects of moderate or severe treadmill exercise in the rats. The SHR were divided into 3 groups: a non-exercising group (Non-Ex), a group conducting moderate treadmill running at 20 m/min 0 degree grade for 60 min (Moderate-Ex) and, a group conducting severe treadmill running at 35 m/min 0 degree grade for 60 min (Severe-Ex) 5 times/week for 4 weeks. Chronic treadmill exercise significantly attenuated the increase in proteinuria and serum total cholesterol levels intensity-dependently. These results were confirmed by morphological analysis of the kidneys. Moderate-Ex provided significantly effective protection against an increase in focal glomerular sclerosis. These results indicate that exercise did not worsen renal function and in contrast, suggest a renal-protective action in this rat model.

Chronic effects of FR139317 and enalapril on renal failure rats with moderate exercise

We assessed the renal effects of moderate treadmill exercise in the spontaneously hypertensive rats (SHR) remnant kidney model of chronic renal failure (CRF). The effects of chronic administration of a specific endothelin (ET) subtype A (ETA) receptor antagonist, FR139317 (32 mg/kg/day i.p.) and an angiotensin-converting enzyme inhibitor, enalapril (2 mg/kg/day i.p.), in combination with moderate exercise were also investigated. Eight-week-old SHR were subjected to 5/6 nephrectomy. One week after surgery the rats were divided into five groups: (a) no treadmill running; (b) moderate treadmill running, 20 m/min for 60 min (Ex) per day; (c) Ex plus FR139317; (d) Ex plus enalapril; and (e) m-Ex plus enalapril in combination with FR139317, for 4 weeks. In SHR-CRF, Ex significantly attenuated the increase in urinary protein excretion. Enalapril significantly attenuated the increase in systolic blood pressure and urinary protein excretion. FR139317 at this dose did not show any antihypertensive or renal protective effect in this model. These results suggest that moderate exercise may protect renal function in SHR CRF. They also suggest that FR139317 may not have an additional antihypertensive and renal protective effect in this exercise model.

Endothelin receptors and angiotensin II receptors in tumor tissue

In cancer chemotherapy, selective enhancement of drug delivery to tumor tissue is essentially important for increase of chemotherapeutic effects. An attenuated vasoconstrictive response to angiotensin II (Ang II) in tumors and a marked increase in tumor blood flow were observed compared with normal tissues during systemic hypertension induced by Ang II infusion. The phenomenon was absent when hypertension was provoked by endothelin-1 (ET-1). We assessed this response to characterize ET receptor and Ang II receptor density and affinity in normal and tumor tissues. The tumor cell line LY80 was transplanted to the skin in nude rats. Four weeks later the rats were sacrificed. [125I] ET-1 and [125I Sar1, Ile8]-Ang II were used to map the receptors for ET and Ang II in rat tissues using computerized in vitro autoradiography. A moderately high density of ET receptors, (ETB > ETA) was found in tumors. The Ang II receptors were markedly reduced in tumor tissues without changes in the affinity. These results suggest that the decrease in Ang II receptors but not ET receptors in tumors may explain the hemodynamic effect of Ang II-induced hypertension and ET-induced hypertension on tumor blood flow.

Selective suppression of antigen-specific Th2 cells by continuous micro-dose oral tolerance

The effect on antigen (Ag)-specific Th2 response as well as IgE production of continuous oral administration of micro-doses of Ag was investigated. Transgenic (Tg) mice carrying the alphabeta-T cell receptor (TCR) genes specific for ovalbumin (OVA) peptide fragment 323-339 were continuously fed with micro-doses of OVA (100 microg/day) for 14 days. Mice were first immunized by OVA in alum and pertussis toxin 7 days before the oral feeding and given a second immunization 1 day after the oral treatment. This feeding regimen tolerized Th2 but not Th1 responses as shown by decrease of Ag-driven cell proliferation and cytokine secretion of IL-4 but not of IL-2 or IFN-gamma as well as by the absence of Ag-specific antibody production of IgE and IgG1, but not of IgG2a or total IgG. Numbers of clonotype-specific TCR-high CD4-positive T cells in peripheral lymphoid tissues markedly decreased in the orally treated group but not in the control group. However, total numbers of CD4-positive T cells in thymus, spleen and lymph nodes were not affected by the oral treatment, indicating that tolerance induction in Th2 cells was mainly due to the down-regulation of TCR and not clonal deletion. The population of antigen-presenting cells expressing B7-2 (CD86) Ag on the surface was decreased in the spleen of the mice which underwent the feeding regimen. The present results suggest that Ag-specific low responsiveness in Th2 cells, which resulted in suppression of the Ag-specific IgE production, can be achieved by continuous feeding with microdoses of Ag.

Cardiac angiotensin converting enzyme and endothelin receptor in rats with chronic myocardial infarction

To ascertain the pathophysiological roles of the renin-angiotensin system and endothelin in heart failure and cardiac hypertrophy, we assessed changes in cardiac angiotensin converting enzyme (ACE) and endothelin-1 (ET-1) receptor using rats in which myocardial infarction was induced by left coronary ligation. The animals were decapitated 1 or 8 months after the operation. Cardiac ACE and ET-1 receptor were quantified by computerized in vitro autoradiography using 125I-MK351A (a lisinopril derivative) and 125I-ET-1. One month after myocardial infarction, cardiac weight and plasma atrial natriuretic peptide had increased in rats with infarction, compared to sham-operated controls, indicating the presence of chronic left ventricular dysfunction, although exchangeable body sodium and plasma renin activity were unchanged. Cardiac ACE increased markedly in the infarcted area and moderately in hypertrophied myocardium without any change in affinity compared to sham-operated rats. On the other hand, there was no change in cardiac ET-1 receptors in infarcted rats. The same results were found even at 8 months after myocardial infarction. The present study indicates that cardiac ACE may participate in tissue repair at the site of myocardial infarction and may also play a role in the pathophysiology of cardiac hypertrophy in rats with chronic heart failure. However, the present results do not reveal whether ET-1 receptor participates in the pathophysiology of cardiac hypertrophy in this model.

Study on microvascular anastomosis of arteries with absorbable polyglyconate suture

A synthetic, monofilament, slowly absorbing suture material, polyglyconate suture was tested to determine its suitability for use in microarterial anastomoses under ordinary tension and under undue tension. Microvascular repair of 34 rat femoral arteries averaging 0.63 mm in diameter using 8-0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 94.1% after 1 to 24 weeks. Microanastomoses of 30 rabbit femoral arteries averaging 1.43 mm in diameter using 8-0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 96.7% when a vessel segment of 3 to 7 mm was resected. Morphological studies included light microscopy and scanning electron microscopy. The results showed that polyglyconate suture retains tensile strength for an adequate period to allow vascular healing and causes a less pronounced tissue response than nonabsorbable nylon suture. Complete absorption of the suture material was followed by a complete regeneration of the vessel wall. These results demonstrated that absorbable polyglyconate suture might be suitable for microvascular anastomosis of arteries under ordinary tension and under tension to a certain degree.

[Alveolar hydatid disease: report of 90 cases]

From 1960 through 1992, 2750 cases of hydatid disease disease were admitted to our hospital, among them there were 90 cases of alveolar hydatid disease proved by laparotomy, biopsy, or autopsy. The preoperative misdiagnosis rate in this series was 24.3% owing mainly to the difficulty of differentiating from multilocular echinococcosis and liver cancer. Basing on clinical and pathological features, the authors proposed its diagnostic and staging principles, and therapeutic approaches to improve the prognosis of this disease.

[Concomitant rupture of bladder and posterior urethra in fracture of pelvis, analysis of 36 cases]

Among 2120 patients with fracture of pelvis, 36 (1.6%) had simultaneous rupture of bladder and posterior urethra. Of the 36 patients 34 were male and 2 female and the ratio of male to female was 17:1. This urological injury is rare and is often misdiagnosed. The following conditions are typical: (1) anuria after pelvic fracture associated with injured urethra or multiple organic trauma; (2) no fullness of bladder for 4 hours after pelvic fracture with urethral injury (except shock or ARF); (3) bloody urinary fluid in peritoneocentesis or increased urea nitrogen in blood (except shock or ARF). Heavy dose IVP could confirm the diagnosis. The principal treatment included repair of ruptured bladder, suprapubic cystostomy, drainage of urinary extravasation, traction of traumatic posterior urethra, reduction and immobilization of pelvic fracture. In this series, all the patients obtained satisfactory results except one who died of serious traumatic shock.

Oxygen radicals and the control of ovarian corpus luteum function

The superoxide radical (SOR) and other reactive oxygen species form in cells during the course of respiration as well as in response to various stimuli. Although well known for their damaging effects, these agents can also work beneficially to control cell function. The present review examines the evidence that oxygen radicals and H2O2 may regulate steroid hormone biosynthesis in the ovarian corpus luteum. Recent findings indicate that luteal cells can employ reactive oxygen species at specific sites in controlling the production of progesterone over the course of the reproductive cycle and in inhibiting its synthesis during regression at the end of the cycle. These studies indicate that oxygen radicals and related compounds may function as intracellular regulators of steroidogenesis in the corpus luteum.

Stimulation of phospholipase A2 by xanthine oxidase in the rat corpus luteum

The ability of the superoxide radical (SOR) generated by xanthine oxidase to activate phospholipase A2 (PLA2) was examined in microsomes prepared from luteinized rat ovaries. Treatment of microsomes with xanthine oxidase resulted in a rapid burst in SOR formation followed by an increase in PLA2 activity. Stimulation of PLA2 activity was dose related and similar in microsomes prepared from control or prostaglandin F2 alpha (PGF2 alpha)-treated rats. Activation was inhibited by the antioxidants, vitamin E and nordihydroguaiaretic acid, and by superoxide dismutase and catalase, which metabolize SOR and H2O2 to remove reactive oxygen species from the cell. The stimulation of PLA2 activity by xanthine oxidase was dependent upon the addition of calcium ions, and it was highest in samples in which cytosol was added to membranes. These results indicate that the SOR and/or H2O2 may mediate PLA2 activation, which may be involved in the luteolytic process.

[Therapeutic effects of epimeric glycyrrhizic acids on hepatic injury in rats]

The effects of the epimeric glycyrrhizic acids (GA), 18 alpha-form and 18 beta-form, on D-galactosamine (Gal)-induced acute liver injury and fulminating hepatic failure (FHF) in rats were studied. In rats of acute liver injury, extensive liver parenchymal cell damage was observed by the elevation of alanine aminotransferase (ALT) activity and confirmed by significant histopathological changes 24 and 48 h after ip Gal 450 mg.kg-1. Moreover, marked elevation in the liver putrescine levels occurred along with that of serum ALT. The spermidine and spermine levels did not alter significantly. GA 18 alpha-form 300 mg.kg-1 ip suppressed the elevation of serum ALT and liver putrescine levels, and improved all the histopathologic features. On the other hand, GA 18 beta-form 300 mg.kg-1, which exhibited inhibitory effects 24 h after ip Gal, showed no action 48 h after ip Gal. The ALT levels in the serum from GA 18 alpha-form, 18 beta-form, vs control groups after 24 h were 70 +/- 24 (P < 0.01) and 78 +/- 42 (P < 0.01) vs 155 +/- 57, and after 48 h were 74 +/- 25 (P < 0.01) and 258 +/- 99 (P > 0.05) vs 293 +/- 110. The putrescine contents (nmol.g-1) in the liver from GA 18 alpha-form, 18 beta-form, vs control after 24 h were 34 +/- 9 (P < 0.01) and 51 +/- 12 (P < 0.01) vs 139 +/- 29, and after 48 h were 16 +/- 3 (P < 0.01) and 150 +/- 11 (P > 0.05) vs 156 +/- 23.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetic method for differentiating mechanisms for ligand exchange reactions: application to test for substrate channeling in glycolysis

We have derived analytical expressions for the kinetics of the two mechanisms involved in ligand substitution reactions. These mechanisms are (i) a dissociative mechanism in which the leaving ligand is first dissociated prior to the binding of the incoming ligand and (ii) an associative mechanism where a ternary complex is formed between the incoming ligand and the complex containing the leaving ligand. The equations obtained provide the theoretical basis for differentiating these two mechanisms on the basis of their kinetic patterns of the displacement reactions. Analysis of these equations shows that an associative mechanism can only generate an increasing kinetic pattern for the observed pseudo-first-ordered rate constants as a function of increasing concentration of the incoming ligand and plateaus, in most cases, at a value higher than the off-rate constant of the leaving ligand. However, a dissociative mechanism can generate either an increasing or a decreasing (kapp decreases with increasing concentrations of the incoming ligand) kinetic pattern, depending on the magnitudes of the individual rate constants involved, and, in either case, it will plateau at kapp equal to the koff of the leaving ligand. Therefore, the decreasing kinetic pattern is a hallmark for a dissociative mechanism. This general method was used to settle the dispute of whether NADH is transferred directly via the enzyme-enzyme complex between glycerol-3-phosphate dehydrogenase (GPDH; EC 1.1.1.8) and L-lactate dehydrogenase (LDH; EC 1.1.1.27).(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in phospholipase A2 activity during luteal regression in pseudopregnant and pregnant rats

The activity of phospholipase A2 was measured in microsomes prepared from ovaries of superovulated pseudopregnant rats during spontaneous and prostaglandin F2 alpha-induced regression and during regression in pregnant rats. Microsome samples were incubated at 40 C for 90 min in Tris buffer (pH 8.3) with 1.0 mM CaCl2 added. The substrate, radiolabeled phosphatidylcholine, was incorporated into liposomes. During spontaneous regression, there was a significant 2- to 4-fold increase in phospholipase A2 activity, when compared with levels at mid-pseudopregnancy (days 8-9). This elevation was correlated with a significant decrease in plasma progesterone concentration. On day 6 or 7 of pseudopregnancy, treatment of rats with luteolytic doses of prostaglandin F2 alpha also caused a significant increase in phospholipase A2 activity, which remained elevated throughout the 72-h sampling period. In pregnant rats there was a small but significant rise in phospholipase A2 activity after parturition. These results indicate that the activity of phospholipase A2 increases during luteal regression in pregnant and pseudopregnant rats and that it could be involved in the mechanism that causes the loss in progesterone secretion.