Monoclonal antihuman thyroglobulin antibodies

Six murine hybridomas secreting monoclonal antihuman thyroglobulin (Tg) antibodies (TAK 1-6) were established by cell fusion techniques. Solid phase RIA was employed to detect the anti-Tg antibody in culture supernatants of hybridomas. The characteristics of these monoclonal antibodies were analyzed by radioimmune blocking assay using rat Tg, human glycoproteins, thyroid hormones, and various preparations of Tg obtained from patients with thyroid disease as inhibitors. In the same system, competitive inhibition studies between 125I-labeled and unlabeled monoclonal antibodies were carried out to determine whether these antibodies recognized the same antigenic determinant. TAK 2 and 3 reacted with human Tg specifically and had equal binding activity using various preparations of human Tg. The other four monoclonal antibodies (TAK 1, 4, 5, and 6) cross-reacted with xenogeneic Tg (rat Tg) and their affinity for human Tg increased as the iodine content of Tg increased. Tg binding to TAK 1 and 4 was inhibited by T4, whereas Tg binding to TAK 5 and 6 was not inhibited by any thyroid hormone or their precursors. In conclusion, we prepared six monoclonal antihuman Tg antibodies. One group is specific for human Tg and recognizes the framework structure unmodified by iodination; the second group reacts with iodination-related epitopes other than iodoamino acids, and the third group recognizes determinants consisting of T4. These monoclonal antibodies provide important probes to detect the polymorphism of human Tg.     

Androgen contributes to gender-related cardiac hypertrophy and fibrosis in mice lacking the gene encoding guanylyl cyclase-A

Myocardial hypertrophy and extended cardiac fibrosis are independent risk factors for congestive heart failure and sudden cardiac death. Before age 50, men are at greater risk for cardiovascular disease than age-matched women. In the current studies, we found that cardiac hypertrophy and fibrosis were significantly more pronounced in males compared with females of guanylyl cyclase-A knockout (GC-A KO) mice at 16 wk of age. These gender-related differences were not seen in wild-type mice. In the further studies, either castration (at 10 wk of age) or flutamide, an androgen receptor antagonist, markedly attenuated cardiac hypertrophy and fibrosis in male GC-A KO mice without blood pressure change. In contrast, ovariectomy (at 10 wk of age) had little effect. Also, chronic testosterone infusion increased cardiac mass and fibrosis in ovariectomized GC-A mice. None of the treatments affected cardiac mass or the extent of fibrosis in wild-type mice. Overexpression of mRNAs encoding atrial natriuretic peptide, brain natriuretic peptide, collagens I and III, TGF-beta1, TGF-beta3, angiotensinogen, and angiotensin converting enzyme in the ventricles of male GC-A KO mice was substantially decreased by castration. The gender differences were virtually abolished by targeted deletion of the angiotensin II type 1A receptor gene (AT1A). Neither castration nor testosterone administration induced any change in the cardiac phenotypes of double-KO mice for GC-A and AT1A. Thus, we suggest that androgens contribute to gender-related differences in cardiac hypertrophy and fibrosis by a mechanism involving AT1A receptors and GC-A.     

Prognostic factors in elderly multiple myeloma patients aged 65 years or older: Comparison with nonelderly patients with multiple myeloma

Background:   Although age is a prognostic factor in multiple myeloma (MM), the prognostic factors in elderly MM patients may be different to those in nonelderly MM patients due to the patient's age. The difference in the significance of prognostic factors between elderly MM patients and the nonelderly MM patients was studied.
Methods:   Forty-two elderly MM patients aged 65 years or older were compared with 68 nonelderly MM patients, who were less than 65 years of age. The characteristics of the elderly patients included: aged 65–81 years (median, 72 years); female/male ratio of 22 : 20; 24 IgG type cases, 13 IgA type cases, one non-secretory case and four cases of Bence-Jones type; one case of stage I, 12 cases at stage II and 29 cases at stage III. The prognostic factors were evaluated by means of univariate analysis and Cox's multivariate analysis.
Results:   The median survival time was significantly shorter in the elderly MM patients (24 months) than in the nonelderly patients (50 months) ( P  < 0.01). Of the univariate prognostic factors, corrected serum Ca (cCa), hemoglobin, serum P, bone marrow plasma cell and uric acid were significant prognostic factors in the elderly MM patients, while nine factors including those listed here, were significant in nonelderly controls. Multivariate analysis showed that serum cCa was the only independent prognostic factor ( P  = 0.019) in elderly MM patients, while serum P and bone lesions were significant prognostic factors in nonelderly MM patients.
Conclusion:   Corrected serum c. (cCa) was an independent prognostic factor in elderly MM patients.     

Vertebral fracture and bone mineral density in women receiving high dose glucocorticoids for treatment of autoimmune diseases

OBJECTIVE: To evaluate the factors influencing the occurrence of vertebral fracture in patients receiving high dose glucocorticoids (GC). METHODS: A cross-sectional study was performed on women who had received at least 0.5 mg/kg of oral glucocorticoid for the treatment of autoimmune diseases for more than 1 month between 1998 and 2003. Logistic regression analysis and chi-square test were used to examine the effects of glucocorticoid dose and other factors on vertebral fractures. Receiver-operating characteristics curve (ROC) analysis was used to determine the bone mineral density (BMD) cutoff value for the risk of vertebral fracture. RESULTS: The study population comprised 160 women, including 35 with vertebral fractures. In ROC analysis, the BMD threshold of the risk of fracture for postmenopausal women (0.787 g/cm2 , T score -2.1) was lower than that for premenopausal women (0.843 g/cm2 , T score -1.7). Among patients with fractures, 7 of 16 premenopausal patients had normal BMD values (T score > -1), whereas only one of 19 postmenopausal patients showed a comparable level of BMD. Additionally, vertebral fracture was more frequent for patients with high total cholesterol values (> 280 mg/dl) than for those with normal total cholesterol values (< 220 mg/dl). Moreover, patients with high total cholesterol values had lower BMD values than those with normal total cholesterol values. CONCLUSION: The fact that vertebral fracture frequently occurred in premenopausal patients with normal BMD and evidence that hyperlipidemia correlated with fracture suggest the pathology of vertebral fracture secondary to high dose glucocorticoid therapy is multifactorial and possibly involves lipid metabolism.     

Doppler echocardiographic features of ventricular septal rupture in myocardial infarction

Doppler echocardiography was used to evaluate the features of interventricular septal rupture in six patients with acute myocardial infarction and to substantiate the hemodynamic data and morphologic findings at surgery or autopsy. Although echocardiographic visualization of the septal rupture was obtained in only two of the six patients, unusual Doppler flow signals were detected in the apical portion of the right ventricle in all six patients. Five patients had unusual flow signals during both systole and diastole; one had such signals only during systole. The location of these unusual flow signals coincided with the site of septal rupture confirmed at surgery or autopsy. The pattern of the flow signals in one cardiac cycle was very similar to that of the pressure difference between the left and right ventricular cavities. These findings indicate that the unusual flow signals represent the left to right shunt flows resulting from septal rupture. In conclusion, Doppler echocardiography may be a very useful tool for diagnosing interventricular septal rupture easily and noninvasively in patients with acute myocardial infarction.     

Association of plasma atrial natriuretic peptide, N-terminal proatrial natriuretic peptide, and brain natriuretic peptide levels with coronary artery stenosis in patients with normal left ventricular systolic function

PURPOSE: To examine whether coronary artery stenosis affects plasma levels of atrial natriuretic peptide (ANP), N-terminal proatrial natriuretic peptide (proANP), and brain natriuretic peptide (BNP) in patients with normal left ventricular systolic function. METHODS: We studied 104 consecutive patients with normal left ventricular function and suspected coronary artery stenosis. Plasma natriuretic peptide levels were measured by immunoradiometric assays. RESULTS: Plasma levels of ANP, N-terminal proANP, and BNP were higher in patients with (n = 65) than in those without (n = 39) coronary artery stenosis, whereas hemodynamic variables were similar. Patients who had coronary artery stenosis with only distal lesions (n = 36) had higher levels of all three natriuretic peptides than did patients with no coronary artery stenosis. N-terminal proANP levels were significantly higher in patients who had coronary artery stenosis with proximal lesions (n = 29) than in patients who had coronary artery stenosis with only distal lesions and those with no coronary artery stenosis. Multiple logistic regression analysis revealed that N-terminal proANP, but not ANP or BNP, was independently associated with coronary artery stenosis after adjusting for clinical and demographic variables (odds ratio per 100 fmol/mL increase = 1.9; 95% confidence interval: 1.9 to 2.6; P = 0.01). However, the sensitivity, specificity, and positive and negative predictive values of each peptide were not sufficiently high to be used for prediction. CONCLUSION: N-terminal proANP may be associated with clinically important coronary artery stenosis in patients with normal left ventricular systolic function, but its clinical usefulness may be limited.     

Haplotype analysis of the human renin gene and essential hypertension

The human renin gene is an attractive candidate for involvement in the underlying cause of essential hypertension (EH). Despite extensive examination, the relation between the renin gene and hypertension remains unclear. The aims of the present study were to discover new genetic markers of EH and to investigate the relations between polymorphisms of the renin gene and EH in the Japanese. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we isolated 3 novel variants of the renin gene; a single nucleotide polymorphism (SNP) in intron 4 (T+17int4G), a variable number of tandem repeats (VNTR) polymorphism in intron 7, and a missense mutation in exon 9 (G1051A). We performed an association study with these polymorphisms in 212 patients with EH and 209 age-matched normotensive (NT) subjects. The frequency of genotypes VNTR and T+17int4G did not differ significantly between the 2 groups, whereas the overall distribution of G1051A was significantly different between EH and NT. Haplotype analysis revealed that the overall distribution of haplotypes differed significantly between the EH and NT groups. PRA levels in patients with EH with the G/G genotype were significantly higher than in subjects with EH with G/A and A/A genotypes. These data suggest that the missense mutation in exon 9 may affect the enzymatic function of renin and consequently may be involved in the etiology of hypertension.     

Excess aldosterone under normal salt diet induces cardiac hypertrophy and infiltration via oxidative stress.

Aldosterone is known to play a role in the pathophysiology of some cardiovascular diseases. However, previous studies on aldosterone infusion have been mostly performed in animals receiving sodium loading and uninephrectomy, and thus the cardiac action of aldosterone alone remains to be fully clarified. The present study was undertaken to investigate the direct cardiac action of aldosterone infusion alone in rats not subjected to salt loading and uninephrectomy. Aldosterone (0.75 microg/h) was subcutaneously infused into rats via an osmotic minipump for 14 days. Aldosterone infusion, under a normal salt diet, induced only a slight increase in the blood pressure of normal rats throughout the infusion. However, aldosterone significantly induced cardiac hypertrophy, as shown by echocardiography and measurement of cardiomyocyte cross-sectional area. Furthermore, aldosterone caused not only cardiac interstitial macrophage infiltration but also cardiac focal inflammatory lesions, which were associated with an increase in cardiac monocyte chemoattractant protein-1 (MCP-1) and osteopontin mRNA. The slight elevation of blood pressure by aldosterone infusion was completely prevented by tempol, the superoxide dismutase mimetic. However, tempol failed to suppress cardiac hypertrophy, the formation of inflammatory lesions, and upregulation of cardiac MCP-1 and osteopontin by aldosterone, while N-acetylcysteine could inhibit all of them. Our data provide evidence that aldosterone alone can induce cardiac hypertrophy and severe inflammatory response in the heart, independently of blood pressure, even in the absence of salt loading or nephrectomy. Aldosterone seems to induce cardiac inflammation and gene expression via oxidative stress that is inhibited by N-acetylcysteine but not by tempol.