[Alteration of the expression of rat cardiac Galphaq/11 and Gialpha2 proteins during endothelin-1 pre-treatment]

The present study was undertaken to explore the mechanism of G protein-mediated signal transduction pathway during endothelin-1 (ET-1) pre-treatment and ischemic preconditioning (IP). Rats were divided into four groups: ET-1, IP, ischaemia-reperfusion (IR) and control groups. ET-1 pre-treatment model was prepared by administrating 0.5 nmol/(L.kg) ET-1 into rat left ventricle, whereas IP model was prepared by ligating the left coronary artery for 5 min followed by 30 min reperfusion. All the animals were subjected to 60 min regional ischaemia and 30 min reperfusion alternately and then parameters of ventricular arrhythmia and expression of cardiac Galphaq/11 and Gialpha2 were measured. The results showed that the scores of ventricular arrhythmia decreased significantly in both ET-1 and IP treated groups as compared with IR group. In comparison with control group, Galphaq/11 increased by 77.8% (P<0.05) and 110.6% (P<0.01) in IP and ET-1 group respectively. Gialpha2 showed no significant difference in IP group, while it decreased by 31.0% (P<0.01) in ET-1 group. In conclusion, activation of G alphaq/11 may be related to the protecting mechanism of ET-1 pre-treatment and IP, whereas Gialpha2 may only play a role in ET-1 pre-treatment.

Central corneal thickness of normal tension glaucoma patients in Japan

PURPOSE

To compare central corneal thickness (CCT) of patients with normal tension glaucoma (NTG) with that of age-matched normal subjects, patients with open-angle glaucoma (POAG) and ocular hypertension (OH) subjects in Japan.

METHODS

Central corneal thickness was measured in 79 NTG, 61 POAG, 73 OH, and 50 normal subjects with an ultrasonic pachymeter. One eye for 1 subject randomly selected in each group was used for inter-group comparison. The relationship between CCT and the maximum intraocular pressure (IOP) measured by Goldmann applanation tonometer with no ocular hypotensive medication (NTG, OH, and normal subjects) or under medication (POAG patients) was analyzed.

RESULTS

The CCT of OH subjects (582 +/- 32 microm; mean +/- SD) was significantly greater than that of the other groups (P <.001), while no difference was seen in CCT among normal (552 +/- 36 microm), NTG (548 +/- 33 microm) and POAG (550 +/- 33 microm) subjects. In normal subjects, CCT and the maximum IOP were significantly correlated but the correlation coefficient was small (r = 0.420, P <.05).

CONCLUSIONS

Central corneal thickness shows no significant difference among NTG, POAG, and normal subjects in Japan, while it is significantly greater in OH subjects. The CCT has little influence on the diagnosis of NTG in Japan.

Osteopontin expression in progressive renal injury in remnant kidney: role of angiotensin II

BACKGROUND

Osteopontin (OPN) is a macrophage chemotactic and adhesion molecule and has been shown to play a role in glomerular and tubulointerstitial injury in several kidney disease models.

METHODS

The present study examined whether OPN expression is involved in the progression of renal disease following subtotal (5/6) nephrectomy (STNx) in rats and whether angiotensin II (Ang II) mediates the up-regulation of renal OPN expression and macrophage accumulation in this model by administering valsartan, an Ang II type I (AT1) receptor antagonist, or ramipril, an angiotensin-converting enzyme (ACE) inhibitor.

RESULTS

In normal and sham-operated rat kidneys, OPN was expressed in a few tubules (<5%) and was absent in glomeruli. Following STNx (weeks 2 to 16), there was substantial up-regulation of OPN mRNA and protein expression in glomeruli [2 to 12 cells/glomerular cross section (gcs)] and tubular epithelial cells (20 to 75% OPN+). The up-regulation of OPN expression was associated with macrophage accumulation within the kidney, severe proteinuria, loss of renal function, and severe histologic damage, including tubulitis and tubulointerstitial fibrosis (all P < 0.001). Treatment with either valsartan or ramipril completely abrogated the up-regulation of OPN mRNA and protein expression in glomeruli and tubules. The reduction in OPN expression was associated with a significant inhibition of macrophage accumulation and progressive renal injury (P < 0.001).

CONCLUSION

An up-regulation of OPN expression may play a role in progressive renal injury following STNx. Inhibition of OPN expression may be one of the mechanisms by which Ang II blockade attenuated renal injury after renal ablation.

Blockade of the renin-angiotensin and endothelin systems on progressive renal injury

The renin-angiotensin system (RAS) and endothelin system may both play a role in the pathogenesis of progressive renal injury. The aims of the present study were 3-fold: first, to explore the possible benefits of dual blockade of the RAS with an ACE inhibitor and an angiotensin type 1(AT1) receptor antagonist; second, to examine the relative efficacy of endothelin A receptor antagonism (ETA-RA) compared with combined endothelin A/B receptor antagonism (ETA/B-RA); and third, to assess whether interruption of both RAS and endothelin system had any advantages over single-system blockade. Subtotally nephrectomized rats were studied as a model of progressive renal injury and randomly assigned to one of the following treatments for 12 weeks: perindopril (ACE inhibitor), irbesartan (AT1 receptor antagonist), BMS193884 (ETA-RA), bosentan (ETA/B-RA), and a combination of irbesartan with either perindopril or BMS193884. Treatment with irbesartan or perindopril was associated with an improved glomerular filtration rate and reductions in blood pressure, urinary protein excretion, glomerulosclerosis, and tubular injury in association with reduced gene expression of transforming growth factor-beta(1) and matrix protein type IV collagen. The combination of irbesartan with perindopril was associated with further reductions in blood pressure and urinary protein excretion. No beneficial effects of either BMS193884 or bosentan were noted. Furthermore, the addition of BMS193884 to irbesartan did not confer any additional benefits. These findings suggest that the RAS but not the endothelin system is a major mediator of progressive renal injury after renal mass reduction and that the combination of an AT1 receptor antagonist with an ACE inhibitor may have advantages over the single agent of RAS blocker treatment.

Co-segregation of elevated LDL with a novel mutation (D92K) of the LDL receptor in a kindred with multiple lipoprotein abnormalities

Factors predisposing to the phenotypic features of familial combined hyperlipidemia have not been clearly defined. In the course of investigating familial coronary artery disease in Utah, we identified a three-generation family in which multiple members were affected with type IIa hyperlipoproteinemia (HLP IIa), type IIb hyperlipoproteinemia (HLP IIb), or type IV hyperlipoproteinemia (HLP IV). Because several family members had relatively severe low-density lipoprotein (LDL) cholesterol elevation, in order to dissect the possible contribution to the plasma lipoprotein abnormalities in this pedigree, we identified a novel point mutation in the low-density lipoprotein receptor (LDLR) gene, a G-to-A transition at nucleotide position 337 in exon 4. This change substituted lysine for glutamic acid at codon 92 (D92K) of the LDL receptor. By means of mutant allele-specific amplification we determined that the mutation co-segregated with elevated cholesterol and LDL cholesterol in the plasma of family members with HLP IIa and HLP IIb, but not with the elevated plasma triglycerides seen in HLP IIb and HLP IV patients. Thus, in families with apparent familial combined hyperlipidemia, a defective LDLR allele and other genetic or environmental factors that elevate plasma triglycerides may account for the multiple lipid phenotypes observed in this kindred.

Production of milligram concentrations of free prostate specific antigen (fPSA) from LNCaP cell culture: difference between fPSA from LNCaP cell and seminal plasma

We have established a procedure for the production of milligrams of free PSA (fPSA) from LNCaP cells derived from a human carcinoma of the prostate. By growing LNCaP cells in a serum-free medium in the presence of a synthetic androgen (R1881) and taking advantage of the special design of the Micro-mouse Hollow Fiber Bioreactor, relatively pure fPSA could be obtained. We found that columns containing either Sephacryl S-100 or S-200 could be used to remove the small amount of bovine serum albumin (BSA) and PSA-alpha 1-antichymotrypsin complex (PSA-ACT) from the preparation. More than 90% of the PSA from LNCaP cell cultures are fPSA. Like fPSA from seminal plasma, two fractions of fPSA differing in protease activity can be separated by DEAE-Sepharose chromatography. Based on the band pattern exhibited on the Western blot following sodium dodecyl sulfate-polyacrylamide electrophoresis separation, fPSA from LNCaP contains more inactive PSA isoforms. This was confirmed by chromatofocusing: the isoelectric point (pl) of the major PSA isoforms from the LNCaP cell culture were higher (6.8 and 6.6) than that (6.4 and 6.1) of fPSA from seminal fluid. We conclude that the LNCaP cell culture is a reliable source for obtaining large quantities of pure fPSA both for the preparation of assay calibrators and controls and for studying the difference in fPSA between benign prostate disease and prostate cancer.

A novel LDLR mutation, H190Y, in a Utah kindred with familial hypercholesterolemia

Heterozygous familial hypercholesterolemia (FH) is a serious disorder causing twice normal low-density lipoprotein (LDL) cholesterol levels early in childhood and very early coronary disease in both men and women. Treatment with multiple medications together with diet can normalize cholesterol levels in many persons with FH and prevent or delay the development of coronary atherosclerosis. Previously published blood cholesterol criteria greatly under-diagnosed new cases of FH among members of known families with FH and over-diagnosed FH among participants of general population screening. Thus, there is a need for accurate and genetically validated criteria for the early diagnosis of heterozygous FH. In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To carry out molecular genetic diagnosis of the disease, we screened DNA samples for mutations in all 18 exons and the exon-intron boundaries of the LDL receptor gene (LDLR). Novel point mutations were identified in the proband: a C-to-T transversion at nucleotide position 631, causing substitution of tyrosine for histidine at codon 190 in exon 4 of the LDLR gene. The mutant allele-specific amplification method was used to examine 12 members of the family recruited for the diagnosis. This method helped to unequivocally diagnose 7 individuals as heterozygous for this particular LDLR mutation, while excluding the remaining 5 individuals from carrier status with FH.

Ratio of remnant-like particle-cholesterol to serum total triglycerides is an effective alternative to ultracentrifugal and electrophoretic methods in the diagnosis of familial type III hyperlipoproteinemia

BACKGROUND

Familial type III hyperlipoproteinemia (HLP) is characterized by the presence of beta-migrating VLDL (beta-VLDL) and increased risk of cardiovascular disease. Assessment of plasma beta-VLDL is achieved by measuring the ratio of VLDL-cholesterol (VLDL-C) to total plasma triglycerides (TGs) or by detecting beta-VLDL in total VLDL. The objective of this study was to compare the clinical utility of the ratio of remnant-like particle-cholesterol (RLP-C) to total TGs with that of the current methods for diagnosing type III HLP.

METHODS

Detection of beta-VLDL by electrophoresis of VLDL was used to define type III HLP. Twenty-eight patients with type III HLP and 43 subjects lacking beta-VLDL were investigated. Fasting TG concentrations were >2.26 mmol/L in all subjects. Subjects were separated into three groups: group 1, serum total cholesterol </=5.18 mmol/L (n = 11); group 2, total cholesterol >5.18 mmol/L and TGs between 2.26 and 9.04 mmol/L (n = 51); and group 3, TGs >9.04 mmol/L (n = 9).

RESULTS

In group 2, a RLP-C-to-total TG molar ratio >/=0.23 (>/=0.10 when using mg/dL) and a VLDL-C-to-total TG molar ratio >/=0.69 (>/=0.30 when using mg/dL) correctly classified 94% and 90% of the subjects, respectively. The utility of the RLP-C-to-total TG ratio in diagnosing type III HLP decreased in patients in the other two groups.

CONCLUSION

When used in an appropriate target population, the RLP-C-to-total TG ratio is a convenient and effective alternative to ultracentrifugal and electrophoretic methods for diagnosing type III HLP.

Air plethysmography in chronic venous insufficiency: clinical diagnosis and quantitative assessment

To define the role of air plethysmography (APG) in the clinical diagnosis and quantitative assessment of chronic venous insufficiency (CVI), APG studies were performed on 582 limbs in 291 patients with signs and symptoms of CVI. One hundred and thirty-one limbs were classified into group I (no evidence of CVI), 291 into group II (mild CVI), and 160 into group III (advanced CVI). On APG, the mean venous filling index (VFI) was 1.45 mL/s, 3.90 mL/s, and 5.25 mL/s in groups I, II, and III respectively (p<0.05). The mean ejection fraction (EF) and mean residual volume fraction (RVF) also showed significant differences between the limbs with CVI and the contralateral normal limbs, but the values were similar for the different severities of CVI limbs. The amount of overlap in VFI, EF, and RVF values among the clinical groups was considerable. Discrimination analysis derived a VFI value of 2.67 mL/s as a cutoff point between normal limbs and limbs with CVI, with a positive predictive value of 96%. In conclusion, APG is a simple and noninvasive test for quantitative assessment of the different components of CVI, valvular reflux, and calf muscle pump function. However, only VFI correlated significantly with the severity of CVI. VFI, with its high positive predictive value, may be useful in diagnosis of CVI, and it may serve as an objective quantitative measurement for monitoring the effect of treatment.

Irradiation-induced extracranial carotid stenosis in patients with head and neck malignancies

BACKGROUND

Carotid stenosis is a recognized complication of external irradiation to the head and neck for malignancy. This study aim to investigate the pattern and prevalence of radiation induced carotid disease, and to identify risk factors associated with significant stenosis.

METHODS

In a comparative cross-sectional study, carotid arteries color flow duplex scan was performed on 240 patients who had received external irradiation to the head and neck area, with a mean interval of 72 months from radiotherapy. They consisted of 181 men and 59 women, with a mean age of 59 years. Fifteen patients had a history of cerebrovascular symptoms.

RESULTS

Internal carotid artery (ICA) stenosis of 70% or greater was detected in 29 arteries in 24 patients. Common carotid artery (CCA) disease of > or =70% was present in 13 arteries in 12 patients. Overall 28 patients had significant ICA/ CCA disease (11.7%). Patients with nasopharyngeal and laryngeal carcinoma had more cerebrovascular symptoms, and more frequent CCA stenosis. Significant ICA/CCA stenosis was associated with age, smoking, coronary heart disease, stroke, no head and neck surgery, time interval from radiotherapy, and the site of primary tumor. On logistic regression analysis age (>60 years), cerebrovascular symptoms, interval from irradiation (>5 years), and nasopharynx and larynx cancer were found to be independent significant (P<0.05) predictors of 70% or greater ICA/CCA stenosis.

CONCLUSIONS

Patients who had received radiotherapy to the head and neck have a high risk of developing significant carotid stenosis. Routine duplex ultrasound screening in these patients is indicated.

Pathological expression of renin and angiotensin II in the renal tubule after subtotal nephrectomy. Implications for the pathogenesis of tubulointerstitial fibrosis

The finding that the systemic renin-angiotensin system (RAS) is not activated in most types of chronic renal disease has led to the suggestion that a local, intrarenal RAS may be an important determinant in the relentless progression of renal disease. Therefore, cell specific changes in various components of the RAS in response to renal mass reduction and angiotensin converting enzyme (ACE) inhibition were examined. Thirty Sprague-Dawley rats were randomly assigned to sham surgery, subtotal nephrectomy (STNx) alone or STNx treated with the ACE inhibitor, perindopril, and sacrificed after 12 weeks. In sham rats, renin mRNA and protein were only present in the juxtaglomerular apparatus. In contrast, in STNx kidneys, renin and angiotensin II expression were noted predominantly in renal tubular epithelial cells in association with overexpression of the prosclerotic cytokine, transforming growth factor-beta1 (TGF-beta1). In perindopril-treated STNx rats expression of renin and TGF-beta1 were similar to control animals. These finding indicate that following renal mass reduction there is pathological tubular expression of various components of the RAS. Furthermore, in contrast to the juxtaglomerular apparatus, tubular renin expression was reduced with ACE inhibition. These changes within the intrarenal RAS may be pathogenetically linked to the development of tubulointerstitial injury.

Familial hypercholesterolemia in Utah kindred with novel 2412-6 Ins G mutations in exon 17 of the LDL receptor gene

Familial hypercholesterolemia (FH) is a monogenic disorder associated with primary hypercholesterolemia. FH is characterized by autosomal co-dominant inheritance with strikingly elevated LDL-cholesterol, the presence of xanthoma and premature atherosclerosis. In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To determine the genetic etiology of the lipoprotein abnormalities, we screened DNA samples from the family for mutations in all 18 exons and the exon- intron boundaries of the low-density lipoprotein receptor (LDLR) gene. Novel point mutations were identified in the proband: a one-base insertion of G to a five-G stretch at nucleotides 2412-6 (codons 783-785), causing a frameshift in exon 17 of the LDL receptor gene. The direct sequencing method was used to examine six members of the family recruited for the diagnosis. This method helped to unequivocally diagnose the five individuals as heterozygous for this particular LDL receptor mutation. This method also helped us to diagnose with FH, or to exclude from carrier status, three children between ages 6 and 11.

Familial hypercholesterolemia in Utah kindred with novel R103W mutations in exon 4 of the LDL receptor gene

Heterozygous familial hypercholesterolemia (FH) is a serious disorder causing twice normal low-density lipoprotein cholesterol levels early in childhood and very early coronary disease in both men and women. Previously published blood cholesterol criteria greatly under-diagnosed new cases of FH among members of known families with FH and over-diagnosed FH among participants of general population screening. Thus, there is a need for accurate and genetically validated criteria for the early diagnosis of heterozygous FH. In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To carry out molecular genetic diagnosis of the disease, we screened DNA samples for mutations in all 18 exons and the exon- intron boundaries of the low-density lipoprotein (LDL) receptor gene. Novel point mutations were identified in the proband: a C-to-T transversion at nucleotide position 369, causing substitution of Tryptophan for Arginine at codon 103 in exon 4 of the LDL receptor gene. The SSCP method was used to examine seven members of the family recruited for the diagnosis. This method helped to unequivocally diagnose only the proband as heterozygous for this particular LDL receptor mutation while excluding the remaining six individuals from carrier status with FH.

[The study of family structure, illness symptom, and stress adaptation of psychotic patients]

The major purposes of this paper are to explore the phenomena of family structure, illness symptoms, family coping and adaptation for patients with schizophrenia or manic-depression psychosis. This paper tries to provide a good reference instrument for application by nurses in home care, in order to understand and evaluate family needs. Subjects are schizophrenic or manic-depression outpatients from 3 hospitals located in northern Taiwan. Data were collected through home interview with primary caregivers and observations. There were fifty subjects from each of the 3 hospitals, and 151 subjects in total. Descriptive statistics, t-test, one way ANOVA, Pearson correlation and multiple stepwise correlation were used to analyze data. Research indicates that most patients are aged between 31 to 40, with over 10 years elapsed since onset, and are not married. Most primary caregivers are parents over 60 years old. Most family development was at the stage with young adult offspring. The manic-depressive patients have more working opportunities than schizophrenic patients. For schizophrenic patients, paranoia was the most serious in active symptoms; lack of interpersonal interaction was the most serious in negative symptoms; the other major problem was sleep disturbance in emotion-behavior assessment. Patient's disposition was the most concerning issue for families and the worst coping efficiency occurred with lazy behavior and sleep disturbance. For manic-depressive patients, aggressive behavior was the most serious active symptom, lack of energy was the most serious in negative symptom, and sleep disturbance was the most concerning problem in emotion-behavior assessment. The patient's symptom was the most concerning issue for families and the worst coping efficiency was found in drug side effect. The result also indicates that active and negative symptoms are both related to coping efficiency.

Enhanced blood pressure response to mild sodium reduction in subjects with the 235T variant of the angiotensinogen gene

The relationship of high salt intake to elevated blood pressure levels has been demonstrated in most populations by cross-sectional, longitudinal, physiological, and clinical intervention studies. Variation within the angiotensinogen gene has been implicated in the genetic control of blood pressure levels and has been suggested to contribute to increased salt sensitivity. A total of 86 hypertensive men and women who had never been treated and who had participated in a 6-month randomized, placebo-controlled, clinical trial of low-sodium mineral salt (19% reduction in urinary sodium versus 12% increase in placebo group) were genotyped at the angiotensinogen M235T locus to test the hypothesis that the 235T allele is associated with a significant blood pressure response to a sodium reduction intervention whereas the 235M allele is not. After adjustment for gender and baseline blood pressure, persons with the TT and MT genotypes showed significant systolic blood pressure reductions on mineral salt compared with control subjects (P = .02 and P = .001, respectively) but not persons with the MM genotype (P = .10). Net adjusted diastolic blood pressure reductions also showed greater significance for persons with the TT and MT genotypes than for persons with the MM genotype (P = .08, P = .01, and P = .83, respectively). The net adjusted systolic and diastolic blood pressure reduction was -8.6/-3.9 mm Hg for persons with the TT genotype, -9.0/-5.2 mm Hg for the MT genotype, and -5.3/-1.0 mm Hg for the MM genotype. We conclude that the 235T allele of the angiotensinogen gene is associated with greater blood pressure decreases than the 235M allele after a sodium reduction intervention. The angiotensinogen gene accounts for some of the interindividual variation of the blood pressure response to sodium reduction.

Screening for asymptomatic carotid stenosis in patients with peripheral vascular disease: a prospective study and risk factor analysis

Screening for asymptomatic carotid artery stenosis using color flow duplex scan was performed on 186 Chinese patients with peripheral vascular disease. They consist of 121 male and 65 females, with a mean age of 70.6 years. A carotid bruit was present in 43 (23.1%) of the patients. Internal carotid artery stenosis of 70% or greater was detected in 46 patients (24.7%) including six total occlusions. Another 79 patients (42.5%) had internal carotid artery stenosis in the 30-69% range. Significant internal carotid artery stenosis was associated with age, male sex, the quantity and duration of smoking and a carotid bruit, and inversely with cholesterol, triglyceride and VLDL. Age, the number of cigarettes consumed per day, and carotid bruit were independent significant predictors of > or =70% internal carotid artery stenosis on logistic regression analysis. The degree of internal carotid artery stenosis is more severe in patients with a carotid bruit, and correlated positively with age (P<0.01), the number of cigarettes smoked (P = 0.04), and the duration of smoking (P = 0.03). Multiple linear regression analysis showed that only the age of the patient bears a significant relationship with the degree of internal carotid artery stenosis (P<0.01). There was no relationship between the degree of lower limb ischemia with carotid stenosis. The prevalence of > or =70% internal carotid artery stenosis in a high risk population with peripheral vascular disease was 24.7%. Routine duplex screening is worthwhile in this group of patients, particularly in male, elderly smokers.

Review of risk factors for cardiovascular diseases

Traditional risk factors for coronary heart disease (CHD) include only the patient's age and family history and whether there is evidence of hypertension, elevated LDL, low HDL, diabetes or history of smoking. In recent years, considerable progress has been made in identifying a new generation of risk factors, including Lp(a). triglycerides, subfractions of HDL and LDL, modified LDL, apo E pheno/genotype, homocysteine and fibrinogen. At the same time, studies have broadened our knowledge of traditional markers. These advances have enabled physicians to make a better assessment of patient risk for CHD and to prescribe more appropriate treatment.

Congenital hypothyroid screening using cord blood TSH

BACKGROUND

Clinical diagnosis of congenital hypothyroidism (CH) is difficult at birth without neonatal screening. In line with the priorities of the national health services in Malaysia towards preventive medicine, early diagnosis and treatment of CH is emphasised. We conducted a pilot study at Kuala Lumpur's Maternity Hospital between April 1995 and November 1995 to estimate the incidence of CH and also evaluated the problems associated with large-scale neonatal screening using a commercial TSH kit on cord bloodspots.

PATIENTS

A total of 11,000 newborns were screened using cord blood spots taken at birth.

RESULTS

Two hundred and fifty newborns (2.27%) hand cord TSH > 20 mlU/L and had to be recalled for re-evaluation. Of these, 4 had cord TSH of > 100 mlU/L; three were confirmed to have congenital hypothyroidism and one had transient hyperthyrotropinaemia. Our study estimated the incidence of CH to be one in 3,666 live births in Kuala Lumpur, Malaysia. Clinical features of hypothyroidism are subtle during the early weeks of life. However, prolonged neonatal jaundice (3/3), widely opened posterior fontanelle (3/3) and dry skin (3/3) were the common features in all our cases by 2-6 weeks of life.

CONCLUSION

This study suffered a high dropout rate. Twenty-six percent of the patients were not traceable after discharge and 48% did not respond to our recall. We stress the importance of public education and awareness in contributing to the cost-effectiveness of the screening program.

Prevalence of significant carotid stenosis in Chinese patients with peripheral and coronary artery disease

BACKGROUND

The prevalence of extracranial carotid stenosis in the Chinese population is not known. This study aims to investigate and compare carotid disease in several groups of high-risk patients.

METHOD

Routine screening carotid duplex scans were performed on high-risk Chinese patients without cerebrovascular symptoms. These consisted of 249 patients with peripheral vascular disease, 207 patients with coronary artery disease, and 45 patients with abdominal aortic aneurysm. In addition, 220 patients with cerebrovascular symptoms and 58 patients with carotid bruits were scanned. A group of 108 healthy individuals was included as a control. The data of all 887 subjects were analysed.

RESULTS

Carotid stenosis of 70% or greater was detected in 37.7% of patients in the cerebrovascular disease group and 24.5% of patients with peripheral arterial disease; it was higher than in patients with coronary artery disease (11.1%), asymptomatic carotid bruit (10.3%) and aortic aneurysms (8.9%; P < 0.001). No significant disease was found in the controls. Patients with cerebrovascular disease have more severe degrees of carotid stenosis and significantly more total occlusions. Smoking, age and male sex were the main risk factors for high-grade (> or = 70%) carotid stenosis.

CONCLUSION

The prevalence of extracranial carotid stenosis in Chinese patients is not low. Patients with peripheral arterial disease have the highest risk of significant carotid stenosis: routine carotid duplex screening in these patients is recommended.

Alterations of G-protein and adenylate cyclase signaling in rat liver during the progression of sepsis

Changes in the protein level of various subunits of G-protein and the activity of adenylate cyclase in rat liver plasma membranes during different metabolic phases of sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). The results show that the protein levels of Galphai-2 and Galphai-3 were unchanged during the early hypermetabolic (hyperglycemic) phase (9 h after CLP), whereas Galphaai-2 and Galphaai-3 were increased by 32.4 and 59.1%, respectively, during the late hypometabolic (hypoglycemic) phase (18 h after CLP) of sepsis. The protein levels of Galphas and Gbeta remained unaltered during both the early and the late phases of sepsis. The activity of adenylate cyclase remained unchanged during the early phase, whereas it was decreased by 26% (p < .05) during the late phase of sepsis. Since the G-protein/adenylate cyclase signaling system mediates hormonal control of hepatic glucose metabolism, the observed increases in the Galphai-2 and Galphai-3 protein levels coupled with a decrease in the activity of adenylate cyclase may contribute to the development of the hypoglycemia during the late stage of sepsis.

Salt induces myocardial and renal fibrosis in normotensive and hypertensive rats

BACKGROUND

The detrimental effects of high dietary salt intake may not only involve effects on blood pressure and organ hypertrophy but also lead to tissue fibrosis independently of these factors.

METHODS AND RESULTS

The effect of a normal (1%) or high (8%) sodium chloride diet on myocardial and renal fibrosis was assessed by quantitative histomorphometry in spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). The effect of salt on transforming growth factor-beta1 (TGF-beta1) gene expression was assessed by Northern blot hybridization. A high-salt diet from 8 to 16 weeks of age resulted in increased blood pressure and left ventricular and renal hypertrophy in both WKYs and SHRs. Marked interstitial fibrosis was demonstrated in the left ventricle (LV), glomeruli, and renal tubules and in intramyocardial arteries and arterioles but not in the right ventricle. The collagen volume fraction increased significantly after high-salt diet in the LV, intramyocardial arteries and arterioles, glomeruli, and peritubular areas in both WKYs and SHRs. In the kidneys, glomerular and peritubular type IV collagen was also increased. There was overexpression of TGF-beta1 mRNA in the LV and kidneys in both rat strains after a high-salt diet (all P<0.001).

CONCLUSIONS

High dietary salt led to widespread fibrosis and increased TGF-beta1 in the heart and kidney in normotensive and hypertensive rats. These results suggest a specific effect of dietary salt on fibrosis, possibly via TGF-beta1-dependent pathways, and further suggest that excessive salt intake may be an important direct pathogenic factor for cardiovascular disease.

Development of an assay for modulating anti-acetylcholine receptor autoantibodies using human rhabdomyosarcoma cell line

Three types of autoantibodies against the acetylcholine receptors (AChR) of skeletal muscle are detectable in patients with myasthenia gravis including binding, blocking, and modulating anti-AChR antibodies. Modulating autoantibodies correlate best with the severity of the disease, but are also technically most difficult to measure because the assay generally requires fresh human muscle cells. We have developed an assay for the modulation of anti-AChR antibodies using a rhabdomyosarcoma (RD) cell line expressing AChR on the cell surface. By decreasing the FetalClone III serum from 10% to 0.5% in Eagles Minimal Essential Medium (EMEM) we were able to increase the number of AChR on RD cells to meet the need of sensitivity of the assay. The extent of modulation was determined as the percent of AChR internalized in the presence or absence of modulating autoantibodies. Less than 6% modulation was found with the normal serum (n = 42). The CVs of both the intra- and day-to-day precision were less than 20%. When clinical samples (n = 105) were assayed in our laboratory and also at Nichols Institute, a correlation coefficient of 0.816 was obtained. The selection of RD cell line, the success of increasing the expression of the AChR on RD cells and the use of 125I alpha-bungarotoxin of high specific activity allowed the establishment of an assay which can be used in routine clinical laboratory for the measurement of modulating anti-AChR autoantibodies for the management of patients with myasthenia gravis.

Familial hypercholesterolemia kindred in Utah with novel C54S mutations of the LDL receptor gene

In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To determine the genetic etiology of the lipoprotein abnormalities, we screened DNA samples for mutations in all 18 exons and the exon- intron boundaries of the low-density lipoprotein (LDL) receptor gene. Novel point mutations were identified in the proband: a T-to-A transversion at nucleotide position 223, causing substitution of Ser for Cys at codon 54 in exon 3 of the receptor gene. This amino acid replacement would disrupt one of the disulfide bonds necessary for maintenance of the secondary structure of the repeat at the N-terminal of the receptor, prevent correct folding of the receptor, and result in defective intracellular transport of the receptor.

[Alterations of cardiac Gi protein alpha subunits during ischemia-reperfusion in rats]

Alteration of G proteins in rat heart during ischemia-reperfusion was studied. Levels of Gi alpha 2, Gi alpha 3 and Gs alpha in sarcolemma and light vesicle were measured by Western blot analysis. Adenyl cyclase activities were determined by radioimmunoassay. During ischemia-reperfusion, cardiac function parameters were decreased significantly. Expressions of Gs alpha remained unchanged. Compared with the control group, levels of Gi alpha 2 and Gi alpha 3 in sarcolemma in ischemia-reperfusion group increased by 37.4% (P < 0.01) and 42.4% (P < 0.01), respectively with, however, no changes in light vesicle; Activities of adenyl cyclase decreased during ischemia-reperfusion. The results suggested that the increased expression of cardiac Gi may contribute to the dysfunction of adenyl cyclase signal transduction system and the impaired cardiac function during ischemia-reperfusion.

Renal expression of transforming growth factor-beta inducible gene-h3 (beta ig-h3) in normal and diabetic rats

BACKGROUND

Transforming growth factor-beta (TGF-beta) has been implicated in the pathogenesis of a number of kidney diseases characterized by glomerulosclerosis and tubulointerstitial fibrosis. TGF-beta is secreted in a latent form requiring extracellular modification to become biologically active. TGF-beta inducible gene-h3 (beta ig-h3) is a recently identified TGF-beta-induced gene product. The present study sought to examine beta ig-h3 expression in normal and diabetic rats.

METHODS

Beta ig-h3, TGF-beta1 and alpha1 (IV) collagen gene expression were assessed by Northern blot analysis and in situ hybridization in 20 Sprague Dawley rats, randomly assigned to receive streptozotocin (diabetic, N = 11) or citrate buffer alone (control, N = 9) and sacrificed eight months later. The effect of exogenous TGF-beta1 on beta ig-h3 expression was also assessed in cultured proximal tubular cells.

RESULTS

In situ hybridization localized beta ig-h3 gene expression to the juxtaglomerular apparatus and the pars recta (S3 segment) of proximal tubules in both control and diabetic animals. Kidney TGF-beta 1, beta ig-h3 and alpha1 (IV) collagen mRNA from diabetic rats were increased two- to threefold compared with controls (P < 0.01). There was a significant correlation between TGF-beta1 and beta ig-h3 gene expression in kidneys from diabetic rats (r = 0.73, P = 0.01). In addition, beta ig-h3 mRNA increased in response to exogenous TGF-beta1 in a dose-dependent fashion in cultured proximal tubular cells.

CONCLUSION

These findings support the hypothesis that biologically active TGF-beta plays a pathogenetic role in diabetic kidney disease and suggest that beta ig-h3 may be a useful index of TGF-beta1 bioactivity in the kidney.