[Association of HLA-DRB genes with Vogt-Koyanagi-Harada syndrome in a Chinese Han population]

OBJECTIVE

To investigate the molecular genetic background of VKH syndrome in Han Chinese by HLA-DRB genotyping.

METHODS

HLA-DRB genotyping was performed by PCR-SSOP method, then DR4 alleles were analyzed by SSOP and RFLP methods.

RESULTS

The frequency of DRB1 * 0405 was significantly higher in VKH patients than that in normal controls (80.4% vs 8.1%, Pc < 10(-7), RR = 46.7), so was the frequency of DRB1 * 15 in DRB1 * 0405 negative individuals (Pc < 0.05, RR = 6.0). On the other hand, the frequencies of DRB1 * 14 and DRB1 * 08 were significantly lower in VKH patients than that in normal controls. Comparing the clinical features between DRB1 * 0405 positive and negative VKH patients, no significant differences were found.

CONCLUSIONS

(1) DRB1 * 0405 and DRB1 * 15 are closely associated with the susceptibility to VKH syndrome, DRB1 * 0405 may be the major susceptible gene and DRB1 * 15 may be the minor; (2) DRB1 * 14 and DRB1 * 08 are negatively associated with the susceptibility to VKH syndrome, suggesting that they may be the resistant genes; (3) DRB1 * 0405 is not related to the clinical features, incidence of ocular complications as well as visual prognosis.

Enhanced delta-opioid receptor-mediated antinociception in mu-opioid receptor-deficient mice

Inflammatory hyperalgesia was induced in wild-type, heterozygous and mu-opioid receptor knockout mice after an intraplantar injection of complete Freund's adjuvant. micro-Opioid receptor knockout mice exhibited faster recovery from hyperalgesia as compared to heterozygous (P<0.05) and wild-type (P<0.01) mice. Naloxone restored hyperalgesia in all genotypes. Naltrindole (delta-opioid receptor-selective antagonist) partially restored the hyperalgesia only in mu-opioid receptor knockout mice (P<0.001). Nor-binaltorphimine (kappa-opioid receptor-selective antagonist) had no effect. The mu-opioid receptor-selective agonist, [D-Ala(2), MePhe(4),Gly-ol(5)]enkephalin (DAMGO), reduced the hyperalgesia in heterozygous and wild-type but not in mu-opioid receptor knockout mice while U69,593 ¿(+)-(5alpha,7alpha, 8beta)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4. 5]dec-8-yl]-benzeneacetamide, kappa-opioid receptor-selective¿ produced similar effects in all mice. The delta-opioid receptor-selective agonists, [D-Pen(2), D-Pen(5)]enkephalin (DPDPE) and deltorphin ([D-Ala(2)]deltrophin-II), produced significantly greater antihyperalgesia in knockout mice (P<0.05). The findings suggest that mu-opioid receptors may be involved in the persistence of inflammatory hyperalgesia and that a delta-opioid receptor-mediated compensatory mechanism in the absence of the mu-opioid receptor is activated by persistent hyperalgesia.

Inner hair cell loss leads to enhanced response amplitudes in auditory cortex of unanesthetized chinchillas: evidence for increased system gain

Carboplatin preferentially destroys inner hair cells (IHCs) in the chinchilla inner ear, while retaining a near-normal outer hair cell (OHC) population. The present study investigated the functional consequences of IHC loss on the compound action potential (CAP), inferior colliculus potential (ICP) and auditory cortex potential (ACP) recorded from chronically implanted electrodes. IHC loss led to a reduction in CAP amplitude that was roughly proportional to IHC loss. The ICP amplitude was typically reduced by IHC loss, but the magnitude of this reduction was generally less than that observed for the CAP. In contrast to the CAP and ICP, ACP amplitudes were generally not reduced following IHC loss. In some animals, the ACP amplitude remained at pre-carboplatin values despite substantial IHC loss. However, in other animals, IHC loss led to an increase ('enhancement') of ACP amplitude. ACP enhancement was greatest at 1-2 weeks post-carboplatin, returning towards baseline amplitudes at 5 weeks post-carboplatin. In other animals, the ACP remained enhanced up to 5 weeks post-carboplatin. We interpret the transient and sustained enhancement of ACP amplitude following partial IHC loss as evidence of functional reorganization occurring at or below the level of the auditory cortex. These results suggest that the gain of the central auditory pathway increases following IHC loss to compensate for the reduced input from the cochlea.

Renal vascular and biochemical responses to systemic renin inhibition in dogs at low renal perfusion pressure

Renin is produced by the kidney and secreted into the systemic circulation. However, its biochemical and physiological role of regulating renal blood flow with changing renal perfusion pressure (RPP) is not fully understood. In this study, the function of the intrarenal renin for production of angiotensin (Ang) I and maintenance of vascular tone was evaluated in dogs under normal conditions and when the kidney was perfused at low RPP. The dog left kidney was perfused first at normal (100 mm Hg) and then at low (30 mm Hg) RPP in the presence or absence of the renin inhibitor ciprokiren (3 mg/kg, i.v.). Both hemodynamic and biochemical parameters were measured. Lowering RPP markedly reduced left renal blood flow and elevated left renal vascular resistance. These effects were prevented by ciprokiren, which blocked the intrarenal production of Ang I. Lowering RPP increased the renal venous/ arterial ratio from 1.4+/-0.1 to 3.6+/-0.3 for plasma renin activity and from 2.4+/-0.2 to 9.8+/-1.1 for Ang I, but did not change the venous/arterial ratio for Ang II. The net renal venous conversion rate of Ang I to Ang II decreased from 0.22 to 0.09 after RPP was lowered, whereas the conversion rate in arterial blood was 1.35 and did not decrease significantly. Our results demonstrated the importance of intrarenal renin-angiotensin system for Ang I production and for the maintenance of the vascular tone, especially at low RPP. Our study also shows the limited capacity for Ang I conversion in the renal vasculature in vivo.

[A study on relationship between hypertension and polymorphism of ACE gene in male Yi people in Liangshan Yi autonomous prefecture, Sichuan]

OBJECTIVE

To explore relationship between polymorphism of ACE gene and hypertension.

METHODS

A cross-sectional study was conducted and PCR technique was used to analyze gene polymorphism.

RESULTS

Genotypes DD, ID and II of ACE gene accounted for 13.0% and 9.7%, 50.9% and 48.4%, and 36.1% and 41.9%, respectively, in the normotensives and hypertensives. Frequencies of I and D alleles for ACE gene were 61.6% and 66.1%, and 38.4% and 33.9%, respectively, in the normotensives and hypertensives. There was no significant difference in distribution of II, ID and DD genotypes and I/D allele frequencies of ACE gene between the hypertensives and normotensives in male Yi people.

CONCLUSION

Association between polymorphism of ACE gene and hypertension was uncertain.

[Extensive HLA class II studies in Chinese narcoleptic patients]

OBJECTIVE

Narcolepsy is a debilitating, lifelong sleep disorder. Its familial occurrence suggests that genetic factors may be of importance in the etiology. Narcolepsy is a very rare disease among Chinese, thus it was of interest to study the association of narcolepsy with the HLA system in Chinese narcoleptic patients.

METHODS

To explore the role of HLA-DRB genes in the development of narcolepsy, we studied 10 narcoleptic patients and 50 race matched controls in whom HLA-DR typing was performed by the method of DNA amplification with sequence-specific primers (PCR-SSP).

RESULTS

All narcoleptic patients were found to be of DRB1 * 1501 and DRB5 * 0101 genotype.

CONCLUSION

These results indicate that HLA-DRB1 * 1501 is a better primary candidate susceptibility gene for narcolepsy in Chinese.

Mibefradil prevents L-NAME-exacerbated nephrosclerosis in spontaneously hypertensive rats

OBJECTIVE

To determine the potential renal protective effects of a novel calcium channel blocker mibefradil in chronic renal failure.

METHOD

We compared the long-term effects of mibefradil with an angiotensin-converting enzyme inhibitor cilazapril on blood pressure, proteinuria, renal function and histological alterations in N-nitro-L-arginine methylester (L-NAME)-treated spontaneously hypertensive rats (SHR). Three groups of SHR were studied for 45 days: group 1 (n = 14), treated with L-NAME only (50 mg/l in the drinking water); group 2 (n = 15) L-NAME plus co-treatment with mibefradil (30 mg/kg per day); group 3 (n = 15), L-NAME plus co-treatment with cilazapril (10 mg/kg per day).

RESULTS

Both mibefradil and cilazapril attenuated the increased systolic blood pressure, and prevented the development of proteinuria and the decreased creatinine clearance (Ccr) seen at day 42 in the group treated with L-NAME alone. Notably, mibefradil had similar effects to cilazapril on proteinuria and Ccr, despite a reduced antihypertensive effect All animals receiving mibefradil co-treatment remained alive throughout the experiment, whereas the mortality rate was 43% in SHR treated with L-NAME alone. Both mibefradil and cilazapril completely prevented renal structural damage as assessed by scoring glomerular, tubulo-interstitial and vascular lesions.

CONCLUSIONS

Our data show that mibefradil prevented the development of hypertension and proteinuria, renal functional impairment and nephrosclerosis, and also improved animal survival. The renal protective effects of mibefradil were at least equivalent to those of an ACE inhibitor in this animal model of chronic renal failure.

Protective effects of endothelin receptor antagonists in dogs with aortic cross-clamping

Endothelin (ET) may play an important role in the pathogenesis of vasoconstriction and acute renal failure after aortic cross-clamping (ACC). However, the relative contribution of the ET(A) and ET(B) receptors to the physiopathology of ischemic acute renal failure is poorly understood. This study was carried out to evaluate the potential protective effect of a selective ET(A) antagonist versus combined ET(A)/ET(B) antagonist on altered systemic, pulmonary, and renal hemodynamics induced by cross-clamping the suprarenal aorta for 1 h, followed by 2-h reperfusion. Studies were performed in three groups of anesthetized mongrel dogs. After baseline measurements, treatment (3 mg/kg i.v. bolus + 3 mg/kg/h infusion) with either a selective ET(A) antagonist, Ro 61-1790 (n = 5), or a combined ET(A)/ET(B) antagonist, bosentan (n = 5) or vehicle (n = 8) was initiated 5 min before ACC. There were marked increases in total peripheral (TPR), pulmonary (PVR), and renal (RVR) vascular resistances, and significant decreases in cardiac output (CO) and glomerular filtration rate (GFR) and tubular sodium reabsorption after ACC in the vehicle group. Both Ro 61-1790 and bosentan prevented the marked increases in TPR, PRV, and RVR, and attenuated the declines in CO, GFR, and tubular sodium reabsorption. We concluded that the profound systemic, pulmonary, and renal vasoconstriction, as well as the impairments in glomerular and tubular functions associated with ACC, is mostly ET mediated and that the ET(A) receptor activation makes a major contribution to the ET-mediated impairments of hemodynamics and renal function after ACC.

Angiotensin I-converting enzyme gene polymorphism in Chinese patients with obstructive sleep apnea syndrome

OBJECTIVE

To investigate the relationship of an insertion/deletion (I/D) polymorphism of the angiotension-converting enzyme (ACE) gene to obstructive sleep apnea syndrome (OSAS) patients and the control subjects.

METHODS

Genomic DNA was extracted from blood samples and amplified by polymerase chain reaction (PCR). PCR primers flanked the polymorphic region in intro 16 of the ACE gene.

RESULTS

OSAS patients had significantly higher frequencies of I/I genotype and insertion allele of the ACE gene as compared with the control subjects in Chinese population. The OSAS patients with I/I genotype had significantly longer apnea time, lower minimum SaO2 and greater AHI than the OSAS patients with I/D genotype.

CONCLUSION

These results indicate that the I/I genotype and I allele are a risk factor for OSAS in Chinese.

Genetic immunization of mice with DNA encoding the 23 kDa transmembrane surface protein of Schistosoma japonicum (Sj23) induces antigen-specific immunoglobulin G antibodies

The 23 kDa transmembrane surface protein of schistosomes is of recognized interest in studies of immune responsiveness in schistosomiasis. To examine the immunogenicity of the 23 kDa antigen of Schistosoma japonicum, Sj23, when delivered by genetic immunization, mice were immunized using a DNA construct containing the Sj23 cDNA under the control of a CMV promotor. Serological analysis of peripheral blood from immunized mice demonstrated that this construct was able to induce the production of antigen-specific IgG antibodies that recognized a schistosome antigen of 23 kDa in Western blots. Despite inducing antigen-specific antibodies, the Sj23 DNA vaccine was unable to confer protection in immunized mice subjected to challenge with S.japonicum cercariae. Appropriate engineering of the unique structure of the Sj23 kDa transmembrane protein of schistosomes may provide a novel vehicle for expressing foreign epitopes from other infectious agents or, possibly, cancer antigens, anchored to the surface of transfected cells.

Optimizing vascular gene transfer of plasminogen activator inhibitor 1

The vessel wall fibrinolytic system plays an important role in maintaining the arterial phenotype and in regulating the arterial response to injury. Plasminogen activator inhibitor type 1 (PAI-1) regulates tissue fibrinolysis and is expressed in arterial tissue; however, its biological role remains uncertain. To help elucidate the role of PAI-1 in the artery wall, and to begin to clarify whether manipulation of vascular PAI-1 expression might be a target for gene therapy, we used adenoviral vectors to increase expression of rat PAI-1 in rat carotid arteries. Infusion of an adenoviral vector in which PAI-1 expression was driven by a promoter derived from the Rous sarcoma virus (RSV) did not increase PAI-1 expression above endogenous levels. To improve PAI-1 expression, we modified the vector by (1) truncating the 3' untranslated region of PAI-1 to increase the mRNA half-life, (2) substituting the SRalpha or the cytomegalovirus (CMV) promoter for the RSV promoter, (3) including an intron in the expression cassette, and (4) altering the direction of transcription of the transgene cassette. The optimal expression vector, revealed by in vitro studies, contained the CMV promoter, an intron, and a truncated PAI-1 mRNA. This vector increased PAI-1 expression by 30-fold over control levels in vitro and by 1.6 to 2-fold over endogenous levels in vivo. This vector will be useful for elucidating the role of PAI-1 in arterial pathobiology. Because genes that are important in maintaining the vascular phenotype are likely to be expressed in the vasculature, the technical issues of how to increase in vivo expression of endogenous genes are highly relevant to the development of genetic therapies for vascular disease.

Endothelin and angiotensin mediate most glomerular responses to nitric oxide inhibition

BACKGROUND

Endothelin (ET) and angiotensin mediate glomerular responses to systemic nitric oxide (NO) inhibition. Acute systemic NO synthase (NOS) inhibition in the rat causes marked increases in both preglomerular (RA) and efferent arteriolar (RE) resistances and a fall in the glomerular capillary ultrafiltration coefficient (Kf). In contrast, local intrarenal NOS inhibition increases RA, but has no effect on RE while producing a similar Kf lowering effect as seen with systemic NOS inhibition. These studies were designed to assess whether the increase in RE during systemic NOS inhibition is mediated by endogenous ET and whether angiotensin II (Ang II) also contributes.

METHODS

Micropuncture measurements were made before and during acute systemic NOS inhibition with N-monomethyl L-arginine (NMA) alone, NMA + the nonpeptide ETA and ETB receptor antagonist, bosentan, NMA + the Ang II type 1 receptor blocker, losartan, and NMA during combined bosentan and losartan.

RESULTS

The falls in single nephron glomerular filtration rate (SNGFR) and glomerular plasma flow seen with systemic NOS inhibition were prevented by concomitant administration of bosentan and losartan alone and in combination. The increases in systemic blood pressure (BP), glomerular BP (PGC), RA, and RE and the reduction in Kf seen with systemic NOS inhibition were attenuated by either bosentan or losartan. An attenuation in the elevation in total renal vascular resistance seen with systemic NOS inhibition was also observed with bosentan. Combined ET and Ang II type 1 blockade completely prevented the increase in systemic BP, PGC, and RE and the fall in Kf with systemic NOS inhibition, leaving only a very attenuated rise in RA.

CONCLUSIONS

These findings suggest that endogenous ET and Ang II partially mediate the glomerular hemodynamic responses (including the increased RE) to acute systemic NOS inhibition. The actions of ET and Ang II are mainly additive, and almost all of the vasoconstrictor responses to acute NOS inhibition are prevented when both vasoconstrictor systems are blocked.

[Association of HLA-DQA1 and DQB1 alleles with Vogt-Koyanagi-Harada syndrome in Han Chinese population]

OBJECTIVE

To access the association of HLA-DQA1 and -DQB1 alleles with Vogt-Koyanagi-Harada syndrome (VKH).

METHODS

The alleles in DQA1 and DQB1 loci of patients with VKH matched with 50 healthy controls were subtyped by polymerase chain reaction-sequence specific primer (PCR-SSP) and PCR-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

DQA1 * 0301 and DQB1 * 0401 alleles were in close association with VKH syndrome, as compared to the controls (Pc < 10(-7)), with the relative risk (RR) 16.47 and 88.00, respectively. The frequency of DQA1 * 0301-DQB1 * 0401 haplotype in patients with VKH was also significantly higher than that in healthy controls (78.6%, 4.0%, Pc < 10(-7), RR = 88.00). Among the 15 patients who were negative for the haplotype of DQA1 * 0301-DQB1 * 0401, 7 of them were found to be positive for DRB1 * 15-DQA1 * 0102-DQB1 * 0602/3 haplotype, with the frequency significantly higher than that in the controls (46.7%, 12.5%, Pc = 0.01, RR = 6.13). However, DQA1 * 0103-DQB1 * 0601 was the only one of the DQA1-DQB1 haplotypes with a significantly lower frequency in patients with VKH in comparison with that in the controls (2.9%, 24%, Pc = 0.001, RR = 0.09). The susceptible haplotype was not related to the clinical features.

CONCLUSIONS

The results suggest that DQA1 * 0301-DQB1 * 0401 and DRB1 * 15-DQA1 * 0102-DQB1 * 0602/3 be associated with the susceptibility in VKH. On the other hand, DQA1 * 0103-DQB1 * 0601 may play a role in resisting against VKH syndrome.

Effects of nonpeptide endothelin receptor antagonists in rats with reduced renal mass

This study was set up to evaluate the long-term effects of nonpeptide endothelin (ET) antagonists in rats with renal mass reduction (RMR). In the first series of experiments, rats were administered bosentan (100 mg/kg/day) or the angiotensin-converting enzyme inhibitor cilazapril (10 mg/kg/day) for 14 weeks beginning 24 h after RMR. As expected, cilazapril completely prevented the development of hypertension, proteinuria, and renal structural damage. In contrast, bosentan had no influence on the development of proteinuria and renal structural damage, although it had a moderate antihypertensive effect and improved creatinine clearance. A second set of experiments was performed to assess whether Ro 48-5695, a very potent ET antagonist optimized from bosentan, could prevent the development of renal damage and reverse established renal damage. Rats received Ro 48-5695 (30 mg/kg/day) beginning either 24 h (prevention) before for 8 weeks, or 4 weeks (reversal) after RMR. Ro 48-5695 attenuated the hypertension and the decline of creatinine clearance when treatment was started at 24 h, but not when started at 4 weeks. Ro 48-5695 had no effect on proteinuria. These observations suggest that ET-receptor activation does not play a major role in the progression of glomerular sclerosis in this model of chronic renal failure.

Screening and treatment of diabetic nephropathy by primary care physicians

OBJECTIVE

To describe the practices of Indiana primary care physicians related to diabetic nephropathy screening and management.

DESIGN

Cross-sectional, observational.

SETTING

The state of Indiana.

PARTICIPANTS

Active primary care physicians (defined as general internists, family practitioners, and general practitioners) in Indiana who provided care for diabetic patients at the time of the survey (n = 1,018)

MEASUREMENTS AND MAIN RESULTS

Practice patterns relevant to microalbuminuria and overt albuminuria screening and management were assessed along two dimensions: the percentage of patients to whom the practices were applied and the frequency with which the practices were performed. Of 1,141 physicians who responded to the survey, 1,018 were eligible for analysis. Eighty-six percent of physicians reported screening more than half of their patients with type 1 diabetes for overt albuminuria, as did 82% of physicians for their patients with type 2 diabetes. Only 17% of physicians indicated performing microalbuminuria testing on more than half of their type 1 patients. Angiotensin-converting enzyme inhibitor agents were used frequently to treat abnormal urinary albumin excretion when hypertension was present, but less often when hypertension was absent. Physician specialty, year of graduation from medical school, practice location, and familiarity with the results of the Diabetes Control and Complications Trial were significant predictors of screening and treatment practice patterns.

CONCLUSIONS

Primary care physicians report practices that allow them to detect overt albuminuria but not microalbuminuria. Angiotensin-converting enzyme inhibitors are frequently used by physicians who test for microalbuminuria, but efforts to increase the detection of early renal damage are needed so that these agents and other therapeutic strategies may be employed at the earliest opportunity.

[Nucleotide sequence at position -155 to +25 of the 5' flanking region of the angiotensinogen gene of Han people]

OBJECTIVE

To study the polymorphism of 5'-flanking region of angiotensinogen gene and relations to essential hyperfension.

METHODS

The nucleotide sequence at position -155 to +25 of the 5'-flanking region in angiotensinogen gene of Han people in Chinese population was identified by applying PCR-single stranded conformational polymorphism(SSCP) and PCR-directed sequencing.

RESULTS

(1) The Han people carry an adenylate(A), instead of a cytidylate(C) at position -20 of the 5'-flanking region of AGT gene; (2) A new mutation T-->A at position -46 was detected and A-allele frequencies was similar in both hypertensives and normotensive controls.

CONCLUSIONS

The variant T-->A at position -46 of AGT gene was not associated with hypertension, but an adenylate (A) at position -20 of the 5'-flanking region of AGT gene. might be an genetic marker for Hans people.

Gene polymorphisms of the renin-angiotensin system in essential hypertension

OBJECTIVE

To determine whether angiotensin-converting enzyme (ACE) gene, angiotensinogen (AGT) gene and angiotensin II receptor 1 (AT1R) gene are implicated in Chinese essential hypertension (EH).

METHODS

The case-control and haplotype-based haplotype relative risk (HHRR) study consisted of 169 essential hypertensive subjects (HT), 152 normotensive controls (NT) and 62 families. The polymorphisms of insertion/deletion (I/D) allele of ACE gene and the microsatellite allele of AT1R gene were determined in DNA extracted from peripheral blood leukocytes by polymerase chain reaction (PCR). The variants of AGT gene were screened by PCR-single strand conformation polymorphism (PCR-SSCP) analysis and further identified by cloning and sequencing.

RESULTS

The significant association between EH and D allele of ACE gene was found (P < 0.05). The difference of the microsatellite allele distribution of AT1R gene between HT and NT groups was statistically significant (P < 0.005). By contrast, the distribution of A-20C genotype of AGT gene was almost identical in HT and NT groups. No significant linkage disequilibrium was observed between A-20C and M235T in AGT gene.

CONCLUSIONS

D allele of ACE gene might correlate with a predisposing factor for EH. The microsatellite allele of AT1R gene might be linkage disequilibrium with an unidentified variant that contributes to the development of EH. A-20C of AGT gene is not a major genetic determinant of EH.

[Angiotension I converting enzyme gene polymorphism in Chinese patients with obstructive sleep apnea syndrome]

OBJECTIVE

To investigate the relationship of an insertion/deletion (I/D) polymorphism of the angiotension-converting enzyme (ACE) gene to obstructive sleep apnea syndrome (OSAS).

METHOD

Genomic DNA was extracted from blood samples and amplified by polymerase chain reaction (PCR). PCR primers were flanking the polymorphic region in intron 16 of the ACE gene.

RESULT

The distribution of the DD, ID, and II ACE genotypes was 16%, 52%, and 32% in the control subjects and 0%, 56%, and 44% in OSAS patients, respectively. The estimated frequencies of the insertion allele and the deletion allele were 58%, 42% in the control subjects and 72%, 28% in OSAS patients, respectively. The differences were statistically significant(P < 0.05). The OSAS patients with I/I genotype had significantly longer apnea time (P < 0.05), lower minimum SaO2(P < 0.05) and more severe AHI (P < 0.05) than did the OSAS patients with I/D genotype.

CONCLUSION

These results indicate that the II genotype and I allele might be a risk factor for OSAS in Chinese.

[HLA-DRB alleles polymorphism in susceptibility to asthma in Beijing Chinese]

OBJECTIVES

To investigate whether susceptibility or resistance to asthma associated with HLA-DRB alleles and analyze the relationship between HLA-DRB genes and clinical phenotype of asthma (TIgE, sIgE, BHR).

METHODS

Using PCR-SSP(sequence-specific primer polymerase chain reaction), we tested the frequency distribution of HLA-DRB alleles in 50 asthmatic patients and 80 healthy volunteers from Beijing China. All patients had their serum TIgE, IgE antibody specific to house dust mite measured by RAST, bronchial responsiveness assessed by methacholine bronch-provocation (if FEV1% > or = 70%), and broncho-dilation measurement by inhaling salbutamol.

RESULTS

There was significantly increased gene frequency of alleles DR6(13), DR52 in asthmatics compared with normal controls (17% vs 4.3%, P < 0.01; 50% vs 17.5%, P < 0.01), and RR was 7.55 and 4.7 respectively. The frequency of DR2(15), DR51 was lower in asthmatics than in controls (7% vs 18% P < 0.01; 2% vs 33.8% P < 0.01). The percentage of HLA haplotype DR6(13)-DR52 was higher in asthmatics than in healthy volunteers (20% vs 4%, P < 0.01, RR 6.4). 70% of individuals sharing DR6(13) gene and 56% of subjects carrying DR52 gene had elevated serum d1 sIgE antibody (> or = +4). There was no relationship between HLA-DRB alleles and total IgE, BHR.

CONCLUSIONS

Alleles DR6(13), DR52 are significantly implicated in their susceptibility to asthma, at least they may be closely associated with this disorder. Conversely DR2(15), DR51 alleles might confer protection against asthma. Positive associations between DR6(13), DR52 and IgE response to d1 allergen are noted. HLA-DRB genes are particularly involved in regulating human atopic immune response.

[Deletion polymorphism in the angiotensin converting enzyme gene associated with essential hypertension in Hans Chinese population]

OBJECTIVE

To investigate whether the polymorphism of the angiotensin-converting enzyme(ACE) gene is associated with essential hypertension in Chinese.

METHODS

A case-control study was carried out using 134 hypertensive (HT) and 165 normotensive (NT) subjects. The insertion/deletion (I/D) polymorphism of ACE gene was detected by polymerase chain reaction (PCR).

RESULTS

The difference of genotype and derived allele frequencies for deletion of ACE gene between hypertensive and normotensive subjects were statistically significant(i.e. 51.9% vs 15.7 and 0.69 vs 0.31 for hypertensive and normotensive respectively, P < 0.05).

CONCLUSIONS

The possession of D/D homozygote genotype of the ACE gene might be a marker for genetic susceptibility to Hans hypertension in Chinese.

HLA-DRB1 genes in 5 rheumatic disease multi-case families

OBJECTIVE

To detect HLA-DRB1 (DR1-10) alleles in 5 families with multi-case rheumatic diseases, and to study the possible influence of DRB1 genes in the pathogenesis of rheumatic diseases.

METHODS

Sequence-Specific Primer PCR (PCR-SSP) method was used to examine HLA-DRB1 alleles. Totally 36 members of 5 families and 166 healthy people were involved in this study. The results were assessed by Chi-square test.

RESULTS

The HLA-DRB1 allele frequency in the patients and their relatives was similar. No significant difference was found. But DR4 allele frequency in the patients (90.9%) and their relatives (68%) was much higher than that in normal controls (16.8%) and the difference was statistically significant (P < 0.0001). In family 4, two RA patients have different DRB1 alleles, while in family 5, two patients have the same DRB1 alleles, one developed SLE and the other developed RA.

CONCLUSIONS

DR4 is closely related to rheumatoid arthritis. The nelatives of RA patients may be at greater risk to develop RA than individuals without family history. Some patients had the same DRB1 allele but developed different rheumatic diseases. This suggested that there might be some common pathways in genetic predisposing of rheumatic diseases. On the other hand, only a few patients with the same DRB1 allele developed rheumatic diseases during their life, so other factors besides DRB1 gene might also be involved in the pathogenesis of rheumatic diseases.

Cationic liposomes enhance adenovirus entry via a pathway independent of the fiber receptor and alpha(v)-integrins

The ability of adenoviral vectors to mediate efficient gene delivery both in vitro and in vivo is limited by the availability of specific cell surface receptors and alpha(v)-containing integrins. We tested whether this limitation could be overcome by enhancing viral entry with cationic liposomes. In cultured vascular smooth muscle cells, delivery of adenoviral vectors in the presence of cationic liposomes increased vector-encoded transgene expression up to 20-fold. The increase in transgene expression was associated with the formation of adenovirus-lipid aggregates and an increase in the amount of vector DNA in the cells, suggesting that enhanced viral entry was responsible for the increase in gene expression. Treatment of the cells with an RGD-containing peptide or adenovirus type 5 fiber protein did not diminish liposome enhancement of transgene expression, indicating that liposomes increase viral entry via a pathway independent of the fiber receptor and of alpha(v) integrin-assisted endocytosis. Liposomes also significantly enhanced transgene expression from adenoviral vectors delivered to cells deficient in alpha(v)-containing integrins. The magnitude of liposome enhancement of transgene expression in cultured smooth muscle cells was greatest during brief periods of virus-cell contact and at low concentrations of virus. Despite these promising in vitro results, addition of liposomes did not improve in vivo adenoviral gene delivery into injured rat carotid arteries. Liposomes can improve adenoviral gene delivery in vitro; however, application of this observation to accomplish improved in vivo gene delivery remains a challenge.

Evolution of chronic nitric oxide inhibition hypertension: relationship to renal function

We conducted longitudinal measurements of blood pressure and renal function in the conscious, chronically catheterized rat before and during acute nitric oxide synthase inhibition (N-nitro-L-arginine methylester [L-NAME], 37 micromol/kg IV) and then chronic administration of oral L-NAME (approximately 37 micromol/kg per 24 hours). These studies specifically investigate the impact on plasma and renal renin as well as volume status during the evolution of this hypertension in rats not subjected to acute experimental stress. Blood pressure progressively increased with chronic administration of L-NAME and reached values greatly above those seen with acute administration of L-NAME. There were parallel increases in renal vascular resistance and development of proteinuria, and glomerular filtration rate began to decline at day 21, coincident with the appearance of renal damage. Twenty-four-hour urinary nitrite and nitrate excretion remained depressed, reflecting reduced nitric oxide synthesis. The plasma renin activity was variable and only increased transiently at 21 days, thus the angiotensin II dependence of this hypertension is not caused by stimulated plasma renin activity. Despite severe hypertension, sodium intake and excretion were unchanged over the 21 days of L-NAME administration. Plasma volume was significantly reduced at days 2 and 12 of L-NAME administration; thus the prolonged plasma volume contraction must result from the acute natriuretic response to the initial acute L-NAME administration.

[Sequence of HLA-DQA1 promoter region in the Han people]

Polymorphism of HLA-DQA1 promoter region (QAP) in the Han people has been identified. The results revealed a number of differences, some of which are in the critical class II boxes, and generally conserved in HLA-DQA1 promoter region. The major differences occurred in the X box, Y box and S box. Within the X box, the Hans carry a A at position -111, instead of a G, and a G or a A can be present at position -98. Within the S box, the Hans carry a G at position -131. Within the Y box, position -71 is a A rather than a G. Some single base substitutions have been detected from IDDM patients at the 5'-flanking region of the S box and between X box and Y box. Particularly, the insertion of CCA bases has been identified at the position between -157 and -158 in a IDDM patient. These data suggest that the polymorphism of HLA-DQA1 promoter region may play a role in susceptibility to IDDM.

Sensitivity of the segmental renal arterioles to angiotensin II in the aging rat

With advancing age the old rat kidney becomes tonically vasoconstricted by endogenous angiotensin II (ANGII) (C. Baylis. Am. J. Kid. Dis., (1993) 842). The present study was designed to investigate the sensitivity of the cortical glomerular microvasculature of the old rat kidney (19-22 months of age) to exogenous ANGII, using the in vivo micropuncture technique. In the baseline state, glomerular blood pressure (P(GC)) in old male rate was higher compared to young rats (4-5 months of age). During exogenous ANGII infusion (40 ng/kg/min), a significant rise in arterial blood pressure and renal vasoconstriction occurred in both young and old rats. In young rats, the ANGII induced fall in renal plasma flow (RPF) and glomerular plasma flow (QA) was accompanied by a rise in PGC and thus the glomerular hydrostatic pressure gradient, with little change in Kf. Therefore, the glomerular filtration rate (GFR) and single nephron GFR (SNGFR) were unchanged by ANGII infusion in young rate. In old rats, RPF and QA fell, a rise occurred in PGC and also a fall was seen in the glomerular capillary ultrafiltration coefficient (Kf), thus GFR and SNGFR fell significantly. The magnitude of the pressor and renal vasoconstriction response to ANGII were not affected by age; of interest, ANGII increased preglomerular and efferent arteriolar resistance (RA, RE) and PGC by similar accounts in young and old rats. SNGFR was reduced in old rats, due to the marked ANGII-induced decline in Kf. Neither absolute nor fractional proximal reabsorbtion were affected by ANGII infusion in either young or old rats. by 19-22 months of age, old rats had much more injured glomeruli than young rats. These data demonstrate that the afferent and efferent arterioles had similar sensitivity to exogenous pressor dose of ANGII in both young and old rats, but Kf was more sensitive to ANGII in old rats leading to a significant fall in SNGFR.

Same eyes, different doctors: differences in primary care physician referrals for diabetic retinopathy screening

OBJECTIVE

To analyze eye care specialist referral patterns for the diabetic patients of primary care physicians.

RESEARCH DESIGN AND METHODS

In 1993, we conducted a census of primary care physicians to evaluate practice patterns relating to diabetes care in the state of Indiana. Using a logistic regression model and data from this census, we compared 1) physicians' odds of referring type II diabetic patients to an optometrist, as opposed to an ophthalmologist, with those of type I diabetic patients and 2) the referral odds ratios of type II to type I diabetic patients between metropolitan and nonmetropolitan counties.

RESULTS

Overall, 10% of the physicians in our study most often refer some patients to an optometrist. Physicians are more likely to refer their type II diabetic patients to an optometrist, as opposed to an ophthalmologist, than they are to refer type I diabetic patients, both before and after adjustment for covariates. Physicians who practice in metropolitan counties are 1.55 times more likely to refer their type II diabetic patients than their type I diabetic patients to an optometrist. In nonmetropolitan counties, physicians are 2.5 times more likely to refer their type II diabetic patients to an optometrist. The difference between metropolitan and nonmetropolitan physicians is significant (P = 0.027).

CONCLUSIONS

Some physicians mostly refer their diabetic patients to optometrists, instead of ophthalmologists, for eye examinations intended to discover early signs of diabetic eye disease. Type II diabetic patients are more likely to be referred to an optometrist, instead of an ophthalmologist, than are type I diabetic patients. In nonmetropolitan areas, the difference in referral patterns becomes even more marked.

[Study on the relationship between primary Sjögren syndrome and HLA-DRbeta gene]

The pathogenesis of primary Sjögren syndrome (PSS) is unclear yet. In order to investigate the role of genetic factor playing in the mechanism of this disorder, we studied the HLA-DR beta gene distributed in 70 patients with PSS and 136 normal subjects by using PCR-SSP technique. The results showed that the gene frequences of HLA-DR3, DR52 and DR2 in patients with PSS were significantly higher than that in normal controls. However, the gene frequencies of HLA-DR5 and DR9 in PSS patients were lower than that in the control group. There were the same genetic phenomena in the siblings of two PSS patients' families. We also found the relationship between HLA-DR52 and the anti-antibodies of SSA or SSB. Our results concluded that the genetic factor is involved in the pathogenesis of primary Sjögren syndrome.

Gestational diabetes: should it be added to the syndrome of insulin resistance?

OBJECTIVE

The significance of gestational diabetes mellitus (GDM) results from its short-term detrimental effects on the fetus and its long-term prediction of NIDDM in the mother. We compared several variables associated with insulin resistance between GDM and non-GDM pregnant women to show the similarities between GDM and NIDDM (and thus insulin resistance).

RESEARCH DESIGN AND METHODS

On the basis of a 3-h oral glucose tolerance test (OGTT), 52 GDM patients and 127 non-GDM patients were recruited from pregnant, non-diabetic women who had a nonfasting 1-h-50-g glucose screening test > or = 7.2 mmol/l (130 mg/dl) performed between 16 and 33 weeks of gestation (a total of 518 of 3,041 women drawn from six community health care prenatal clinics were screened positive). During the OGTT, several potential markers of insulin resistance were measured at fasting and 2-h time points, in addition to the standard glucose measurements. The relationship of these variables with the diagnosis of GDM was studied.

RESULTS

GDM patients, compared with non-GDM patients, had 1) higher prepregnancy weight (P = 0.011), prepregnancy BMI (P = 0.006), C-peptide at fasting (P = 0.002) and at 2 h (P < 0.001), insulin at fasting (P = 0.001) and at 2 h (P < 0.001), triglycerides at fasting (P = 0.005) and at 2 h (P = 0.003), free fatty acids at fasting (P = 0.017), beta-hydroxybutyrate at fasting (P = 0.007); and 2) lower HDL cholesterol at fasting (P = 0.029). These variables were all predictive of GDM (P < 0.036) individually. Using stepwise logistic regression with all of these variables available, fasting (P = 0.019) and 2-h (P < 0.001) insulin levels, fasting free fatty acids (P = 0.031), and fasting beta-hydroxybutyrate (P = 0.036) were statistically significant as jointly predictive of GDM. Comparisons between GDM patients and non-GDM patients matched by BMI confirmed that the metabolic abnormalities persisted when difference in BMI was taken into account. Concomitant blood pressure measurements in women with GDM did not differ significantly from those without GDM.

CONCLUSIONS

Our results show that many of the known metabolic components of the syndrome of insulin resistance (syndrome X) are predictive of GDM. These results are in keeping with the argument that GDM is one phase of the syndrome of insulin resistance. We suggest that GDM be looked upon as a component of the syndrome of insulin resistance that provides an excellent model for the study and prevention of NIDDM in a relatively young age-group.

[Clinical use of bilateral cervico-thoracic skin flaps]

In order to study the clinical efficacy of bilateral cervico-thoracic skin flap on repairing the contracture of the burn scar of the neck, 66 flaps were used in 33 patients from 1983 to 1995. The size of the flap ranged from 5 cm x 6 cm to 8.5 cm x 15 cm. The donor site was covered with split skin graft. The ratio between the length and the width of the flaps should not exceed 3:1. Fifty-nine flaps survived completely, but 7 had necrosis of small area which was healed without any influence on the function and appearance. The operative technique of the bilateral cervico-thoracic skin flaps were reported. The advantages of this type of skin flap and its applied anatomy and the postoperative care were discussed. In the repair of the cicatritial contracture deformity of the neck, it was important to define whether the skin defect was located in the submandibular, anterior cervical or anterior thoracic region, thus appropriate type of repair could then be given accordingly.

[Study on the association of HLA-DR4 with IDDM susceptibility in a Chinese population]

HLA-DR4 and its subtypes were studied by PCP/SSP, PCR/SSOP, and PCR/RFLP methods in 81 patients with IDDM and 106 normal controls in the Han's nationality Chinese population. The results showed no difference in frequencies of DR4 between the IDDM group and the controls (21.0% vs 17.9%), but DRB1*0405, as a subtype Dw15, was significantly associated with IDDM susceptibility (58.8% vs 21.1%, RR = 2.67, P < 0.05). In a family with 2 IDDM patients, it has been found the haplotype DRB1*0405-DQB1*0302 was to be cosegregated with IDDM. It was suggested that DW15 subtype might be associated with IDDM in Chinese because of linkage disequilibrium with DQw8 (DQB1*0302). As an additional evidence, the findings above mentioned may account for the different association of different DR4 subtypes with IDDM in various ethnic groups.

Primary care physicians' practice patterns and diabetic retinopathy. Current levels of care

BACKGROUND

Diabetic retinopathy is a costly and prevalent complication of diabetes mellitus.

OBJECTIVE

To assess primary care physicians' self-reported practice patterns for the screening and detection of diabetic retinopathy relative to published guidelines.

PARTICIPANTS AND METHODS

All primary care physicians (defined as general internists, family practitioners, and general practitioners) in Indiana were identified and surveyed using a mailed questionnaire. Of 2390 physicians, 1508 (63%) responded and were determined to be eligible. Of these 1508 physicians, 1058 (70%) completed all or some of the eye care-related questions. For each eye care practice, physicians were asked to specify the proportion of patients to which the practice was applied and the frequency (eg, every 3 months) with which the behavior was performed, if appropriate. Physicians were also asked to distinguish between patients with type I (insulin-dependent) and type II (non-insulin-dependent) diabetes mellitus for each practice behavior.

RESULTS

Physicians' responses were classified as "high," "moderate," or "low" based on the American Diabetes Association guidelines. Forty-five percent of the physicians' responses were classified as high for referring all of their patients with type I diabetes mellitus to an eye care specialist annually as were 35% of the physicians' responses for referring their patients with type II diabetes mellitus. Fewer physicians reported high levels of routine in-office funduscopic examination. No relationship was found between the extent to which physicians performed an in-office funduscopic examination and patterns of referral to eye care specialists. Logistic regression analysis suggested that recent graduates and general internists are most likely to report behavior that is considered high (P < .05).

CONCLUSION

The diabetic retinopathy-related practice patterns of primary care physicians in Indiana differ significantly from published guidelines.

HLA-DRB1 alleles genotyping in patients with rheumatoid arthritis in Chinese

OBJECTIVE

To explore the role of HLA-DRB1 genes in the development of rheumatoid arthritis (RA) and the correlations between HLA-DR alleles and clinical manifestations of patients with RA.

METHODS

86 patients with rheumatoid arthritis and 106 race matched controls were studied in whom HLA-DR typing was performed by the method of DNA amplification with sequence-specific primers (PCR-SSP). The subtypes of HLA-DR4 were determined by the method of hybridization of PCR products with sequence-specific oligonucleotides (PCR-SSO). The absence or presence of HLA-DR4 and its subtypes was correlated with the clinical and serological characteristics of the patients.

RESULTS

Compared with controls, an increased gene frequency of HLA-DR4 (48.8% vs 17.9%, P < 0.001) and a decreased frequency of HLA-DR7 (16.3% vs 27.4%, P = 0.06) were found. The DRB1* 0405 account for 61.9% of DR4+RA patients and 21.1% of DR4+ controls (P < 0.01). There was no difference between the DR4+ and DR4- patients with respect to age, sex, duration of disease, rheumatoid factor (RF), extra-articular manifestations including secondary Sjogren's syndrome. According to the wrist X-ray stage, the patients of DR4+ were more severe than that of DR4- (P < 0.05).

CONCLUSION

HLA-DR4 and DR4 subtype of DRB1*0405 are related to the development of RA in Chinese. HLA-DR4 can be a useful prognostic marker in the patients with RA.

[Association of polymorphism in 5'-regulatory region of angiotensinogen gene with essential hypertension]

The association of the variant in the 5'-regulatory region of angiotensinogen gene with primary hypertension in the Han Nationality in China was studied by applying PCR-SSCP analysis and DNA cycle sequencing. The frequencies of three identified SSCP-patterns (pattern-A, B, C) in 73 hypertensive subjects were compared with those in 74 normal controls. It was found that the number of pattern-C was higher in the study group (5/73) than in the controls (1/74). The results of DNA sequencing showed that the difference of three SSCP-patterns was caused by a nucleotide substitution G-->A at -216 locus in the 5'-upstream region of angiotensinogen gene, and the subjects with pattern-C were homozygous for mutant A-allele (genotype A/A). These results suggest that the identified gene variant may be associated with primary hypertension.

The role of human leukocyte antigen in susceptibility and clinical manifestations of sarcoidosis

OBJECTIVE

To investigate the correlation of human leukocyte antigen (HLA) with susceptibility and clinical manifestations of sarcoidosis.

MATERIAL AND METHODS

Fifty-five patients with sarcoidosis and one hundred and six normal subjects were investigated. Genomic DNAs were purified using the proteinase K-phenol extraction method. DNA samples were amplified by the polymerase chain reaction (PCR) procedure using the DRB1 group specific primer pairs.

RESULTS

The gene frequency of HLA-DR5 increased significantly in patients with sarcoidosis (P < 0.01), and HLA-DR7 decreased (P < 0.05). Gene frequencies of HLA-DR9 and HLA-DR5 increased remarkably in male patients and in patients with stage I and stage IIa, respectively (both P < 0.05).

CONCLUSIONS

It is suggested that HLA-DR gene might contribute to the susceptibility as well as various clinical manifestations of sarcoidosis.

Importance of nitric oxide in the control of renal hemodynamics

The kidney vasculature is under tonic control by nitric oxide (NO) and in cortex, NO controls RA and Kf. Systemic NO inhibition leads to systemic hypertension, increases in RE, mediated by Ang II and ET, and direct effects on RA and Kf. The relationship between NO and other vasoconstrictor systems is variable. In the conscious relaxed animal, vasoconstrictor activity is low, yet acute NO inhibition leads to pressor and renal vasoconstrictor responses. At physiologic levels, ET unexpectedly is a renal vasodilator, possibly via NO generation at RA. When vasoconstrictor activity is high, NO is very important in maintenance of renal perfusion. Chronic L-NAME produces dose dependent systemic and glomerular capillary hypertension and eventual proteinuria and glomerular damage. NO deficiency is key in this process, although the hypertension becomes refractory to L-arginine administration and dependent on Ang II and the SNS, by mechanisms not yet defined. In contrast, the renal vasculature remains fully responsive to L-arginine, suggesting that pressor and renal vascular responses to chronic NO inhibition are separately regulated. NO generated from iNOS does not normally control BP or renal hemodynamics. The relative contributions of NO from bNOS and eNOS, and importance of NOS in different locations in the kidney, remain to be determined.

[Nucleotide sequence of HLA-DQA1 promoter region (QAP) in a lung cancer patient]

The HLA-DQA1 allele and nucleotide sequence of HLA-DQA1 promoter region (QAP) in a patient with IDDM complicated lung cancer have been identified by PCR/SSCP, PCR/SSCP and PCR/sequencing. The results showed that: (1) All of the lung cancer patient and his family members carried HLA-DQA1* 0301/0501 alleles. (2) a single base substitution G-->A at position -155 and deletion CAA at position -161 to -163 occurred in the patient. These results suggest that the mutation of HLA-DQA1 promoter region may modulate HLA-DQA1 gene expression by trans-acting factors binding to variant cis-acting elements and may be responsible for pathogenesis of lung cancer.

Phosphodiesterase inhibitors correct resistance to natriuretic peptides in rats with Heymann Nephritis

Experimental nephrotic syndrome is characterized by abnormal sodium metabolism, reflected in a blunted natriuretic response both to volume expansion and to infused atrial natriuretic peptide (ANP). The studies presented here examined the relationships among plasma ANP concentration and urinary sodium (VNaV) and cyclic GMP excretion (UcGMPV) in vivo, and the responsiveness of isolated glomeruil and inner medullary collecting duct (IMCD) cells to ANP and urodilatin (renal natriuretic peptide; RNP) in vitro in rats with Heymann nephritis, an immunologically mediated model of nephrotic syndrome. Nine to 14 days after Ip injection of anti-Fx1A antiserum, rats were proteinuric and had a blunted natriuretic response to intravenous infusion of isotonic saline (2% body weight, given over 5 min). Thirty min after the onset of the infusion, plasma ANP concentration was increased to the same extent in both normal and nephritic rats, compared with their respective hydropenic controls. Despite this increase, UcGMPV was significantly less in nephritic rats after the saline infusion. Accumulation of cGMP by isolated glomeruil and IMCD cells from nephritic rats after incubation with ANP and RNP was also significantly reduced, compared with normal rats. This difference was not related to differences in either density or affinity of renal ANP receptors, but was abolished when accumulation of cGMP was measured in the presence of 10(-3) M isobutylmethylxanthine or Zaprinast, two different inhibitors of cyclic nucleotide phosphodiesterases (PDE). Infusion of Zaprinast into one renal artery in nephritic rats normalized both the natriuretic response to volume expansion and the increase in UcGMPV from the infused, but not the contralateral, kidney. Furthermore, cGMP-PDE activity was increased in IMCD cell homogenates from nephritic compared with normal rats (388 +/- 32 versus 198 +/- 93 pmol/min per mg protein, P < 0.03). These results indicate that blunted volume expansion natriuresis accompanied by cellular resistance to ANP in vitro occurs in an immunologic model of renal injury. The resistance is not related to an alteration in ANP release or binding to its renal receptors, but is suppressed by PDE inhibitors and is associated with increased renal cGMP. PDE activity, thus suggesting that enhanced cGMP-PDE activity may account for resistance to the natriuretic actions of ANP observed in vivo. This defect may represent the intrinsic sodium transport abnormality linked to sodium retention in nephrotic syndrome.

[Induced-expression of MHC-DR molecules on mice islet cells]

The correlation of induced-expression of MHC-DR molecules with insulin release in cultured mice islet cells has been studied. The results showed that, (1) No detectable induced-expression of MHC-DR molecules by TNF-alpha alone at the concentration of 50-100 U/ml has been assayed, but the induced-expression of MHC-DR molecules has been identified in a few islet cells (8.5 +/- 2.9%) with IFN-r alone at concentration of 50-100 U/ml. (2) The induced-expression of MHC-DR molecules has been detected in as high as 80% of cultured islet cells with TNF-alpha and IFN-r combined at different concentrations. (3) Insulin released from cultured islet cells was enhanced by IFN-r and TNF-alpha either alone or combined at different concentrations. These results suggest that the induced-expression of MHC-DR molecules themselves does not damage the function for insulin release in cultured islet cells.

Endothelin modulates the pressor actions of acute systemic nitric oxide blockade

Acute nitric oxide blockade not only potentiates the vasoconstrictor actions of endothelin but also enhances the synthesis and release of endothelin. To investigate whether the vasoconstrictor actions of acute nitric oxide blockade are modulated by endothelin, studies were conducted in the conscious, chronically catheterized rat. Renal function was measured before and during acute nitric oxide blockade with nitro-L-arginine methylester (L-NAME), L-NAME + endothelin blockade with the endothelin-converting enzyme inhibitor phosphoramidon, or L-NAME + the nonpeptide ETA and ETB receptor antagonist Bosentan. The increases in blood pressure and RVR seen with acute nitric oxide blockade were attenuated by either method of concomitant endothelin blockade. The falls in RPF and GFR were not blunted because endothelin blockade produced parallel reductions of both pressor and renal vasoconstrictor responses to acute nitric oxide blockade. Endothelin blockade alone with either endothelin-converting enzyme inhibitor or the nonpeptide ETA and ETB receptor antagonist had little effect on blood pressure, RPF, or RVR, but increases in urinary sodium excretion and a small decline in GFR were observed with Bosentan. These observations indicate that endogenous endothelin exerts a tonic antinatriuretic action in the normal conscious rat and partially mediates the pressor actions of acute nitric oxide blockade.

[Analysis of HLA-DRB1 alleles in patients with IDDM]

HLA-DR association with IDDM in local population in Beijing was studied by PCR/SSP typing. The frequency of HLA-DR9 was significantly higher in diabetic patients (30.3% [45/148] vs 17.92% [38/212], chi 2 = 6.97, P < 8.3 x 10(-3)). DR3 was higher in diabetic patients in this study (7.0% [10/148] vs 2.36% [5/212], chi 2 = 3.19, P > 0.05) and DR2 was lower in patients with IDDM (7.4% [11/148] vs 19.8% [42/212], chi 2 = 9.67, P < 1.9 x 10(-3)). These results suggest that DR9 and DR3 both were positively associated with IDDM, but DR2 was negatively associated with IDDM.

Acute changes in urinary excretion of nitrite + nitrate do not necessarily predict renal vascular NO production

NO2 + NO3 (NOx), the stable oxidation products of NO, and cGMP are widely accepted as indices of in vivo NO production. Whether acute changes in urinary excretion of nitrite + nitrate (UNOXV) can be taken to reflect acute changes in renal and/or systemic NO production is not known. The present studies were conducted in the conscious rat to investigate the effect on acute changes in UNOxV, of maneuvers that (a) enhance NO production and (b) act as diuretics. L-arginine (L-arg) and acetylcholine (Ach) produce equivalent NO dependent falls in renal vascular resistance (RVR), but a much greater increase in UNOX V is seen with L-arg. D-arg does not stimulate NO and has no renal vasodilatory effect, but produces a large rise in UNOX V, and SNP lowers BP but not RVR and results in a reduced UNOX V. None of the diuretics employed should stimulate the NO system or lower RVR; however, the proximally acting agents, acetazolamide and D-arg increased UNOx V, while the loop diuretic furosemide had little effect. H2O diuresis (a distal event) led to a fall in UNOx V. These data suggest that NOx is reabsorbed extensively in the proximal tubule and that inhibition of proximal reabsorption leads to an increase in UNOx V. Also, our results show that the relationship between UNOx V and UcGMP V is unpredictable. Therefore, we conclude that measurements of acute changes in UNOxV and/or UcGMP V should be interpreted cautiously, since they may reflect altered tubular handling of NOx rather than the acute activity of the systemic and/or renal NO systems.

Actions of endogenous endothelin on glomerular hemodynamics in the rat

Both endothelin (ET) ETA/ETB receptors are distributed in the glomerular microcirculation, but their physiological functions, if any, are unknown. We used a nonpeptide mixed ETA/ETB receptor antagonist (Bosentan) and a selective ETA receptor antagonist (BQ-123) to investigate the glomerular hemodynamic actions of endogenous ET in the anesthetized euvolemic rat. Blockade of ETA and ETB receptors with Bosentan produced a small fall in systemic blood pressure and a large fall in glomerular blood pressure due to a significant increase in preglomerular (afferent) arteriolar resistance. Single-nephron glomerular filtration rate was not reduced because of an offsetting rise in the glomerular capillary ultrafiltration coefficient. Blockade of the selective ETA receptor with BQ-123 had no effect on blood pressure or glomerular hemodynamics. These observations indicate that endogenous ET is of physiological importance in control of glomerular hemodynamics. Surprisingly, endogenous ET tonically dilates rather than contracts the preglomerular arteriole, and it also tonically lowers the glomerular capillary ultrafiltration coefficient, probably by contracting the mesangial cell. All physiological glomerular actions of ET are mediated via the ETB receptor.

An association study between essential hypertension and HLA-DRB1 alleles

It is well established that genetic and environmental factors are involved in the etiology of essential hypertension (EH). Previous studies have suggested that at least one of the HLA genes is responsible for the genetic susceptibility to EH. Our aim in the present study was to investigate this issue in China by the PCR-SSP HLA-DRB1 typing method. The results showed an increased frequency of HLA-DR2 and a decreased frequency of HLA-DR7 with EH patients compared with controls. We consider that HLA-DR2 may represent a marker for susceptibility to EH in the North Chinese population.

Modulation of ANP-dependent effects of endothelin by inhibitors of neutral endopeptidase and cGMP phosphodiesterase

Endothelin 3 (ET3) infusion increases the concentration of atrial natriuretic peptide (ANP) in plasma, which in turn raises hematocrit (Hct) through a transcapillary shift of plasma fluid and proteins into the interstitium, thereby reducing plasma volume (PV). The level of ANP bioactivity in peripheral target tissues is a function of ANP secretory rate and the turnover rate of ANP and its intracellular effector mechanisms. Neutral endopeptidase (NEP) is a widely distributed enzyme that participates in ANP catabolism, whereas cGMP-phosphodiesterase (PDE) degrades the intracellular second messenger of ANP. Therefore, we examined the consequences of inhibition of NEP and PDE on the ANP-dependent activity described above using the NEP inhibitor SQ 28,603 and the cGMP-PDE inhibitor zaprinast (M&B 22,948). In anesthetized, bilaterally nephrectomized rats, infusion of SQ 28,603 alone reduced mean arterial pressure (MAP) by 2.5 +/- 0.5% and increased Hct by 4.6 +/- 0.3% (P < .01 for both), leading to a calculated decrease in PV of 7.5 +/- 0.6%. These changes were prevented by pretreatment with rabbit anti-rat ANP antiserum. Simultaneous infusion of ET3 (25 ng/kg/min) and SQ 28,603 caused MAP to increase by 12.8 +/- 2.2%, an effect identical with that observed after ET3 alone (12.7 +/- 2.3%), whereas the increase in Hct of 9.4 +/- 0.4% was greater (P < .05) than the 7.5 +/- 0.4% increase seen with ET3 alone. ET3 increased plasma ANP concentration (599 +/- 135 vs. 108 +/- 13 pg/ml in vehicle-infused rats; P < .0001); ET3 and SQ 28,603 infused simultaneously increased plasma ANP even further (810 +/- 166 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

[Detection of mutation in insulin receptor gene in patients with essential hypertension]

We have analyzed single-stranded conformational polymorphism (SSCP) to screen for mutation in exon 17 of insulin receptor gene in 46 patients with hypertension and 49 normotensive controls. Three different SSCP patterns were detected in both patients and controls and the frequency of pattern I was 54.3% and 32.7% (chi 2 = 3.71, P = 0.05) in patients and controls respectively; The frequency of pattern II was 61.3% and 26.1% (chi 2 = 10.49, P = 0.001) in controls and patients respectively; the frequency of pattern III did not differ between controls and patients. Based on direct sequencing, the differences between pattern II and pattern I were explained by a mutation substituting at position 1040, GAG1040-->GAA1040, which suggests that codon GAA1040 may be a genetic marker for susceptibility to essential hypertension in Chinese.

Rapid HLA-DRB1 generic typing by PCR-SSP method

We report a simple and rapid HLA-DRB1 generic typing method, PCR-SSP, which is practical and inexpensive. We use 9 sequence-specific primers and 2 group specific primers to define the HLA-DRB1 specificities DR1, DR2, DR3, DR4, DR5, DR6, DR7, DR8, DR9 and DR10. The HLA DR3, DR5, DR6 and DR8 can be amplified by the two primers of DR3568 and DRB1. The DR6 specificity can be identified by excluding the DR3, DR5 and DR8 when the DR3568 are positive. Any individuals can be typed with some exception: the three pairs of phenotype DR3/DR3 and DR3/DR6, DR5/DR5 and DR5/DR6, DR8/DR8 and DR8/DR6 cannot be discriminated from each other. We typed 106 unrelated healthy people from Beijing locations in two weeks. We think this typing method is suitable to replace the error-prone serologic HLA-DR tests in routine clinical practice, including the prospective typing of cadaveric organ donors.

Renal effects of acute amino acid infusion in hypertension induced by chronic nitric oxide blockade

L-Arginine is the physiological substrate of nitric oxide, a vasodilator that controls blood pressure and renal hemodynamics in the basal state. In the present studies, we produced chronic nitric oxide blockade by oral administration of the L-arginine analogue NG-nitro-L-arginine methyl ester, which produced sustained hypertension and increased renal vascular resistance in conscious rats. Acute excess L-arginine had little effect on blood pressure but completely normalized renal vascular resistance and increased renal plasma flow in chronically nitric oxide-blocked hypertensive rats. In contrast to L-arginine, D-arginine had no renal hemodynamic effects in either normal or chronically nitric oxide-blocked rats. Acutely administered glycine was ineffective in vasodilating the chronically nitric oxide-blocked rat kidney, in a dose that produced renal vasodilation in normal rats. These findings indicate the following: (1) Hypertension induced by chronic nitric oxide blockade due to substituted L-arginine analogue cannot be acutely reversed with excess L-arginine, suggesting that the maintenance of the hypertension is not solely caused by competitive inhibition of nitric oxide production; (2) in contrast, the kidney remains responsive to L-arginine whereas the renal vasodilator response to glycine is abolished in this model of hypertension.

[Association of polymorphism for HLA-DQA1 promotor region (QAP) with IDDM]

We have identified the DNA polymorphism for the HLA-DQA1 promotor region (QAP) in patients with early and late onset insulin-dependent diabetes mellitus (IDDM) by PCR direct sequencing. The result showed that single nucleotide substitution at position-92(C-->T-92) and -146 (T-->C-146) were detected in QAP for early and late onset IDDM respectively. These findings suggests that the mutation seems to alter the conformation of QAP so that these are likely to influence the aberrant expression of MHC-class II loci in beta-pancreatic islet cells.

Angiotensin II and alpha 1-adrenergic tone in chronic nitric oxide blockade-induced hypertension

Nitric oxide (NO) is a tonically produced vasodilator that maintains blood pressure (BP) in the normal animal. In these studies, we produced chronic NO blockade by oral administration of the NO synthesis inhibitor nitro-L-arginine methyl ester (L-NAME), which produced sustained hypertension and increased renal vascular resistance (RVR) in conscious rats. Acute blockade of the angiotensin II type 1 (AT1) receptor with losartan had little effect on BP and RVR in either chronically NO-blocked or normal conscious rats. Acute blockade of the alpha 1-adrenoceptor with prazosin produced moderate similar falls in BP in both chronically NO-blocked and normal rats. The combination of AT1 and alpha 1-adrenoceptor blockade was profoundly antihypertensive and was particularly effective in lowering BP in chronically NO-blocked rats where the hypertension was obliterated. In contrast, the increased RVR persisted in chronically NO-blocked rats receiving combined acute AT1 and alpha 1-adrenoceptor blockade. These observations indicate that, in the sustained phase of chronic NO blockade, the hypertension is largely due to the combined activities of alpha 1-adrenoceptor and AT1 stimulation.