PubMed Health⌕ Search

Biomedical subjects

Claudio E Kater

Publications and source records attributed to Claudio E Kater.

17 recordsLinked to original sources
PubMed2006

[Polycystic ovary syndrome, metabolic syndrome, cardiovascular risk and the role of insulin sensitizing agents].

The Polycystic Ovary Syndrome (PCOS) affects 6 to 10% of women of childbearing age. Insulin resistance and hyperinsulinemia are present in nearly all PCOS patients and play a central role in the development of both hyperandrogenism and metabolic syndrome (MS). MS occurs in approximately 43% of PCOS patients, raising the cardiovascular risk to up seven fold in these patients. Several serum, functional and structural markers of endothelial dysfunction and subclinical atherosclerosis were described in PCOS patients, even those young and non-obese. However, despite the fact that PCOS adversely affects the cardiovascular profile, long-term studies did not demonstrate a consistent raise in cardiovascular mortality, which seems to be more observed in the post-menopausal period. Recently, oral contraceptives are being substituted for insulin sensitizing agents (metformin and glitazones) in the PCOS treatment, due to their effects on insulin resistance and cardiovascular risk.

Atherosclerosis↗
PubMed2006

Serum 21-Deoxycortisol, 17-Hydroxyprogesterone, and 11-deoxycortisol in classic congenital adrenal hyperplasia: clinical and hormonal correlations and identification of patients with 11beta-hydroxylase deficiency among a large group with alleged 21-hydroxylase deficiency.

INTRODUCTION: 21-Hydroxylase deficiency (21OHD) is the most common cause of congenital adrenal hyperplasia, followed in frequency by 11beta-hydroxylase deficiency (11betaOHD). Although the relative frequency of 11betaOHD is reported as between 3 and 5% of the cases, these numbers may have been somewhat underestimated. MATERIALS AND METHODS: In 133 patients (89 females/44 males; 10 d-20.9 yr) with alleged classic 21OHD and five (three females/two males; 7.3-21 yr) with documented 11betaOHD, we measured serum 21-deoxycortisol (21DF), 17-hydroxyprogesterone (17OHP), and 11-deoxycortisol (S), 48 h after glucocorticoid withdrawal. We also studied 20 sex- and age-matched control subjects. Serum steroid levels were determined by RIA after HPLC purification. OBJECTIVES: The objectives of this study were to: 1) quantify 21DF in patients with congenital adrenal hyperplasia, 2) correlate hormonal with clinical data, and 3) identify possible misdiagnosed patients with 11betaOHD among those with 21OHD. RESULTS: In 21OHD, 17OHP (217-100,472 ng/dl) and 21DF (<39-14,105 ng/dl) were mostly elevated and positively correlated (r = 0.7202; P < 0.001). Except for higher 17OHP in pubertal patients, 17OHP and 21DF values were similar according to sex, disease severity, or prevailing glucocorticoid dose. One additional patient with 11betaOHD was detected (1%) and also one with apparent combined 11beta- and 21OHD. S levels were elevated in 11betaOHD and normal but significantly higher in 21OHD than in controls. CONCLUSION: To recognize patients with 21- and/or 11betaOHD, we recommend evaluation of 17OHP or 21DF and S. Also, 21DF may be useful to follow up pubertal patients with 21OHD. Because 1% of patients with alleged 21OHD may have 11betaOHD, its frequency seems underestimated, as per our experience in a Brazilian population.

17-alpha-Hydroxyprogesterone↗
PubMed2006

C'est si bone.

Explore the source record for details and available documents.

Aphorisms and Proverbs as Topic↗
PubMed2006

[Divergent responses of serum testosterone and cortisol in athlete men after a marathon race].

Physical exercise alters homeostasis, as it requires prompt mobilization of metabolic sources. In this study, we measured serum testosterone (T) and cortisol (C) levels and the muscle-wastage enzymes CK, CKMB and LDH in 20 healthy male athletes (ages 25 to 40 years) in response to a marathon race (42.2 km). Venous blood samples were drawn in 3 different periods: (i) in the morning, 48 h before the competition (control), (ii) at the end of the race (end), and (iii) in the next morning, 20 h after the race (recovery). At the end, T was significantly lower (from 673 to 303 ng/dl) and C higher (from 20.3 to 42.5 microg/dl) as compared to the control period. At recovery, both were virtually identical to control levels. CK, CKMB and LDH were significantly higher at the end of the competition and even higher in the recovering period (except for CKMB), characterizing muscle wastage. CK and LDH disclosed a significant negative correlation with T (-0.412 and -0.546, respectively), whereas CKMB correlated positively with C (0.4521). We conclude that the inverse correlation observed between T and C levels, and the pattern of CK, CKMB and LDH increase, allow us to confirm that a marathon race may cause a marked physical stress, resulting in a distinct hormonal imbalance and severe cellular damage.

Adult↗
PubMed2005

The syndromes of low-renin hypertension: "separating the wheat from the chaff".

Primary aldosteronism (PA) is characterized by hypertension and suppressed renin activity with or without hypokalemia and comprises the aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia or idiopatic hyperaldosteronism (IHA). In recent series employing the aldosterone (aldo, ng/dL):renin (ng/mL.h) ratio (ARR) for screening, prevalence of PA among hypertensives soars to 8-20%; current predominance of IHA (>80%) over APA suggests the inclusion of former low-renin essential hypertensives (LREH), in whom plasma aldo can be reduced by suppressive maneuvers. We evaluated the test characteristics of the ARR obtained retrospectively from 127 patients with PA (81 APA; 46 IHA) and 55 with EH (30 LREH; 25 NREH) studied from 1975 to 1990. Using the combined ROC-defined cutoffs of 27 for the ARR and 12ng/dL for aldo, we obtained 89.8% sensitivity (Ss) and 98.2% specificity (Sp) in discriminating PA from EH: all APA and 72% of the IHA patients had values above these limits, but only one (3%) with LREH. Among the 46 IHA patients, 10 (21.7%) had ARR <27, four of whom with aldo <12ng/dL, virtually indistinguishable from LREH. Use of higher cutoff values (ARR > or =100; aldo > or =20) may attain 84%Ss and 82.6%Sp in separating APA from IHA. Because IHA and LREH ("the chaff") may be spectrum stages from the same disease, definite discrimination between these entities seems immaterial. However, precise identification of the APA ("the wheat") is critical, since it is the only surgically curable form of PA. Thus, while patients who may harbor an APA must be thoroughly investigated and surgically treated, non-tumoral disease (IHA and LREH) may be best treated with an aldo-receptor antagonist that will also prevent the aldo-mediated inflammatory effects involved in myocardial fibrosis and abnormal cardiac remodeling.

Adenoma↗
PubMed2005

One-year clinical evaluation of single morning dose prednisolone therapy for 21-hydroxylase deficiency.

Replacement schedules with hydrocortisone (HC) to treat 21OHD are generally unsatisfactory and partially successful regarding growth. Noncompliance is common since its short half-life requires TID administration. Even multiple daily HC doses do not reproduce cortisol chronobiology and may disturb hypothalamic-mediated rhythms. Because synthetic glucocorticoids could improve clinical control, we evaluated the possible benefits of a one-year treatment period with a single morning oral dose of prednisolone (PD) phosphate in 44 patients with 21OHD randomized to two sex and age-matched groups: one (n=23) receiving PD (2.4-3.5 mg/m2 BSA) and the other (n=21) TID HC (10-15 mg/m2 BSA). After one year, bone maturation ratio was kept stable in the PD group (from 1.20 to 1.14), whereas a slight increase was seen in the HC group (from 1.21 to 1.29). Growth velocity (SDS) was preserved in the PD group (from 1.2 to 1.2 in all; 0.79 to 1.13 in pre-pubertals), whereas a slight increase occurred in the pre-pubertal HC-treated patients (from 1.1 to 1.9); height SDS for BA increased significantly in the PD group. Thus, patients with 21OHD treated for one year with a single morning dose of PD appear to achieve a better clinical and hormonal control than those on TID HC, permitting a reduction of the replacement dose. The current PD schedule used by our group (1.5-3 mg/m2 BSA/day) suggests a higher HC:PD bioequivalence ratio of 6-8:1.

Adolescent↗
PubMed2005

[Primary adrenal insufficiency in adults: 150 years after Addison].

Thomas Addison first described, 150 years ago, a clinical syndrome characterized by salt-wasting and skin hyperpigmentation, associated with a destruction of the adrenal gland. Even today, over a century after Addison's report, primary adrenal insufficiency can present as a life-threatening condition, since it frequently goes unrecognized in its early stages. In the 1850s, tuberculous adrenalitis was present in the majority of patients, but nowadays, autoimmune Addison's disease is the most common cause of primary adrenal insufficiency. In the present report, we show the prevalence of different etiologies, clinical manifestations and laboratorial findings, including the adrenal cortex autoantibody, and 21-hydroxylase antibody in a Brazilian series of patients with primary adrenal insufficiency followed at Divisão de Endocrinologia da Universidade Federal de São Paulo (UNIFESP) and at Faculdade de Medicina de Ribeirão Preto-USP (FMRP-USP).

Addison Disease↗
PubMed2004

Two intronic mutations cause 17-hydroxylase deficiency by disrupting splice acceptor sites: direct demonstration of aberrant splicing and absent enzyme activity by expression of the entire CYP17 gene in HEK-293 cells.

To date, only two among 46 mutations in the CYP17 gene cause 17-hydroxylase deficiency (17OHD) by disrupting mRNA splice donor sites. We studied two subjects with intronic CYP17 mutations: a compound heterozygote for Y329D plus an AG to CG substitution at the 3' end of intron 2, and a homozygote for a TTTT deletion near the 3' end of intron 3. We hypothesized that both mutations caused 17OHD by disrupting splice acceptor sites. To prove this mechanism, the entire CYP17 genes (wild type and both mutations) were amplified, subcloned into pcDNA3, and expressed in HEK-293 cells. The mRNA derived from the wild-type CYP17 gene was correctly spliced and translated into active enzyme, as shown by the correct sequence in the RT-PCR products and by the 17-hydroxylation of progesterone. In contrast, cells expressing the mutant genes had no 17-hydroxylase activity. The mRNA derived from the AG to CG mutation used the first AG in exon 3 as the splice acceptor site, shifting the reading frame and introducing a stop codon. RNA derived from the TTTT deletion skipped exon 4 entirely, deleting 29 amino acids in-frame. Our data show that these are the first two 17OHD cases resulting from mutations that alter splice acceptor sites. These studies also demonstrate the feasibility of expressing the entire CYP17 gene, with simultaneous protein and RNA analysis, as a general methodology for characterizing how intronic CYP17 mutations cause 17OHD.

Adult↗
PubMed2004

Two prevalent CYP17 mutations and genotype-phenotype correlations in 24 Brazilian patients with 17-hydroxylase deficiency.

We performed molecular genetic analysis of 24 subjects from 19 families with 17-hydroxylase deficiency in Brazil. Of 7 novel CYP17 mutations, 2 (W406R and R362C) account for 50% and 32% of the mutant alleles, respectively. Both mutations were completely inactive when studied in COS-7 cells and yeast microsomes; however, phenotypic features varied among subjects. Some 46,XY individuals with these genotypes had ambiguous genitalia, and other subjects had normal blood pressure and/or serum potassium. We found mutations W406R and R362C principally in families with Spanish and Portuguese ancestry, respectively, suggesting that two independent founder effects contribute to the increased prevalence of 17-hydroxylase deficiency in Brazil. Mutations Y329D and P428L retained a trace of activity, yet the two individuals with these mutations had severe hypertension and hypokalemia. The 46,XX female with mutation Y329D reached Tanner stage 5, whereas the 46,XY subject with mutation P428L remained sexually infantile. The severity of hypertension, hypokalemia, 17-deoxysteroid excess, and sex steroid deficiency varied, even among patients with completely inactive CYP17 protein(s). Spontaneous sexual development occurred only in 46,XX females with partial deficiencies. We conclude that other factors, in addition to CYP17 genotype, contribute to the phenotype of individual patients with 17-hydroxylase deficiency.

Adolescent↗
PubMedDate not supplied

Urinary free cortisol is similar in older and younger women.

The increased cortisol secretion that occurs with aging is associated with characteristics of frailty. In this study we investigated whether healthy elderly women excrete increased amounts of urinary free cortisol (UFC) when compared to younger women. Twenty-four-hour UFC levels were measured in 25 elderly (70 to 87 years of age; median: 74) and 24 younger (19 to 59 years of age; median: 46) community-living women. All subjects were healthy and cognition was unimpaired. No differences in 24-hr UFC were observed between elderly and younger women (54.2 +/- 28.0 and 45.1 +/- 15.6 micrograms/24 hr, respectively) and no correlation was found between 24-hr UFC and age. Also, elderly and younger women had similar 24-hr urinary volumes (1366 +/- 531 and 1514 +/- 412 ml 24 hr, respectively) that did not correlate with UFC. In conclusion, older and younger healthy women have similar 24-hr UFC levels, possibly reflecting a comparable adrenocortical secretion of cortisol.

Adult↗
PubMedDate not supplied

The effect of hospitalization on the sleep pattern and on cortisol secretion of healthy elderly.

The aim of this study was to verify whether polysomnography represents a stressful situation by assessing cortisol levels and the sleep pattern of healthy community-living elderly admitted to a sleep disorder center (SDC). Subjects slept for two sequential nights at the SDC for polysomnographic recordings. Blood was sampled at 0800 h, 1600 h, and 2300 h and 24-h urine was collected for cortisol determination. Three months later, subjects were visited at home for blood and urinary collections. Cortisol levels were higher in the SDC than at home at 0800 h but were lower at 2300 h and similar at 1600 h. No differences were observed in urinary cortisol. Polysomnographic recordings indicated a poorer sleep pattern in the first night. Our data indicate that a short-term stay of healthy elderly in a SDC disrupts sleep pattern in the first of 2 nights, without representing a stressful experience, as evaluated by cortisol levels.

Aged↗
PubMedDate not supplied

Reversed-phase high-performance liquid chromatography separation of adrenal steroids prior to radioimmunoassay: application in congenital adrenal hyperplasia.

21-Hydroxylase deficiency (21-OHD) is the most common form of congenital adrenal hyperplasia (CAH), followed by 11beta-hydroxylase deficiency (11beta-OHD). Diagnostic serum markers for these conditions are 17-hydroxyprogesterone (17-OHP) and 11-desoxycortisol (S), respectively. In 21-OHD, the large amounts of 17-OHP are further 11beta-hydroxylated to form 21-deoxycortisol (21-DF), making it also an excellent marker of this disease. These steroids can be measured in blood by radioimmunoassay (RIA). In this paper, we report the use of high-performance liquid chromatography (HPLC) for steroid purification, prior to RIA determinations of 21-DF, S, 17-OHP, and testosterone (T) in ether-extracted serum. The chromatographic separation is developed in a BDS-Hypersil column using water-methanol (53:47, v/v) as the mobile phase. The method is applied to 35 patients with the classic form of 21-OHD (18 females, 17 males, 5.1-14.2 years old) and 2 with 11beta-OHD (1 female, 1 male, 9.5 and 12.6 years old). Thirteen control children (5 females and 8 males, 5.2-15.2 years) are also studied. The results obtained for all measured steroids are compatible with those reported in the literature. The method is precise, and recovery is adequate. The HPLC technique proved to be of value for the purification of several steroids from single serum samples prior to RIA in patients with CAH.

17-alpha-Hydroxyprogesterone↗