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PubMed2000

Differential expression of growth hormone messenger ribonucleic acid by somatotropes and gonadotropes in male and cycling female rats.

Past studies have reported the appearance of cells sharing phenotypic characteristics of gonadotropes and GH cells. During diestrus and early proestrus, a subset of somatotropes (40-60%) expressed both GH antigens and gonadotropin (LH-beta, LHbeta, or FSH-beta) messenger RNAs (mRNAs) or GnRH receptors. More recently, we reported that subsets of gonadotropes identified by LHbeta or FSHbeta antigens expressed GH- releasing hormone (GHRH) binding sites. The present studies were designed to learn if these putative multipotential cells also expressed GH mRNA. Biotinylated sense and antisense oligonucleotide probes were developed and cytochemical in situ hybridization tests were optimized for the detection of GH mRNA with GH, LHbeta, and FSHbeta antigens. RNase protection assays were developed with a complementary RNA probe that detected a 380-bp region at the 5' end of the GH mRNA. Both the in situ hybridization and RNase protection assays detected changes in expression of GH mRNA during the estrous cycle with the lowest expression occurring during metestrus and peak expression occurring on the morning of proestrus. Cell counts confirmed the results of the RNase protection assays showing that increases in mRNA levels seen from metestrus to proestrus reflected increased percentages of GH mRNA-bearing cells. In addition, densitometric analyses demonstrated that the higher GH mRNA levels assayed from diestrus to proestrus reflected increased area and density of label per cell. Both types of assays showed sex differences in expression of GH mRNA; male rat cell populations had higher values than female rats in metestrus, diestrus, or estrus. However, percentages of GH cells in male rats were equal to those from proestrous female rats and levels of GH mRNA were lower in male rats than proestrous females. Dual labeling experiments showed that, in male rats and diestrous, proestrous, or estrous females, GH mRNA was expressed in over 70% of GH cells. Expression of GH mRNA was also found in 50-57% of cells with LHbeta or FSHbeta antigens in the same groups. The lowest expression was seen in the metestrous groups (30-40% of GH cells or gonadotropes expressed GH mRNA). Expression of GH mRNA was first increased from metestrus to diestrous largely in GH cells, and slightly in cells with LHbeta antigens. Further increases were seen in GH and LH cells by the morning of proestrus. In contrast, FSH gonadotropes did not show an increased expression of GH mRNA until the morning of proestrus (reaching the same peak reached by LH cells). These data confirm the working hypothesis that a multihormonal cell type develops during diestrus to support both the somatotrope and gonadotrope populations. Collectively, our studies suggest that this multihormonal cell may function to help support the regulatory functions of the gonadotrope during the periovulatory period. In addition, the appearance of significant levels of expression of GH mRNA by male rat gonadotropes suggests that this multihormonal cell may play a role in regulation of the male reproductive system as well.

Animals↗
PubMed2004

Combined orthotopic heart and liver transplantation: the need for exception status listing.

Through May 2004, 33 combined orthotopic heart-liver transplants (OHT/OLT) have been performed nationwide. No published data exist to date regarding outcomes of patients awaiting such transplants, although progression of two organ disease processes may contribute to premature death for waiting patients. Retrospective data were collected on patients listed for combined OHT/OLT from both an individual tertiary care transplant center and the national UNOS registry to delineate listing criteria and evaluate patient outcomes in both the pre- and post-MELD eras. All patients who survived to transplantation or died on the waiting list were included in the analysis. Results show that 29.6% of patients registered nationally and 42% of patients listed institutionally survived to transplantation. Survival to transplantation was associated with less severe liver disease, though patients with MELD scores ranging from 19 to 26 had significantly higher wait list mortality than expected when compared to single-organ liver transplants. Following combined orthotopic heart-liver transplantation, 80% and 70% of patients survive 1 and 3 years, respectively. In conclusion, combined OHT/OLT is a successful therapy, but current organ allocation policies may not ensure expeditious transplantation in critically ill patients with dual vital organ failure. Providing exception status listing to these patients would ensure more expeditious transplantation and potentially contribute to improved survival.

Adult↗
PubMed1983

Two membrane oxygenators and a bubbler: a clinical comparison.

We compared the hemocompatibility of the Polystan bubble oxygenator and the Travenol TMO and SciMed spiral-coil membrane oxygenators in 43 patients undergoing aortic valve replacement. In a subgroup of 27 patients, we collected hematological data and correlated platelet behavior with hemostasis. We found no differences in blood loss or blood (product) requirements among the groups. Platelet and erythrocyte damage was less in the membrane oxygenator groups than in the bubble oxygenator group. Differences in adenosine diphosphate-induced platelet aggregation were equivalent. Drops in this function concurred with intensified cardiotomy suction and administration of protamine. Leukocytosis after bypass was most marked in the SciMed group. Duration of bypass correlated with blood loss and blood requirements in the operating theater. Platelet counts shortly after bypass correlated negatively with duration of bypass and blood loss in the intensive care unit. Platelet function correlated with none of the factors just mentioned. We conclude that platelets and erythrocytes are preserved better by the membrane oxygenator than by the bubbler. The TMO system causes more erythrocyte damage than the SciMed oxygenator, probably due to TMO's dual-pump system. Clinical evidence for these improvements was not found, and this will be possible only when the other factors responsible for blood damage can be controlled.

Adult↗
PubMed2004

Examination of MCP-1 (CCL2) partitioning and presentation during transendothelial leukocyte migration.

It is proposed that a chemokine concentration gradient promotes vectorial leukocyte migration across the vascular endothelium during inflammation. In this study, monocyte migration across a model endothelial monolayer was assessed at defined time-points after the addition of MCP-1 (CCL2). At each time-point transendothelial migration was quantified, medium from the apical and basal surface was collected for ELISA and monolayers were stained to detect both heparan sulfate and MCP-1. Statistically significant monocyte migration was observed within 60 min of chemokine addition to the basal surface of the endothelium and an asymmetric distribution of MCP-1 across the monolayer was observed at all time-points. Dual color immunofluorescence analysis demonstrated that MCP-1 was focused into heparan sulfate-containing domains on the apical surface of some of the endothelial cells. Furthermore, no uniform concentration gradient of chemokine was observed within the space between adjacent endothelial cells with apical MCP-1 application resulting in a staining pattern identical to that observed after basal application. The addition of a functional, monomeric form of MCP-1 produced a staining pattern identical to that observed using the wild-type protein, suggesting that localized chemokine oligomerization is not responsible for generating the focal chemokine distribution. Together, these data suggest that apical presentation of concentrated, chemokine-containing domains provides sufficient stimulus to promote transendothelial leukocyte migration in the absence of the formation of a formal haptotactic concentration gradient between endothelial cells.

Binding Sites↗
PubMed2002

Females experiencing sexual and drug vulnerabilities are at elevated risk for HIV infection among youth who use injection drugs.

OBJECTIVES: To compare sociodemographic, drug-related, and sexual risk variables between young (13-24 years of age) and older (> or =25 years of age) injection drug users (IDUs); and to determine HIV prevalence and associated risk factors for HIV infection among young IDUs. METHODS: Data were collected through the Vancouver Injection Drug Users Study (VIDUS). To date, over 1400 Vancouver area IDUs have been enrolled and observed during follow-up. Sociodemographic, drug-related, and sexual risk variables were compared between younger and older IDUs using nonparametric methods. Mantel-Haenszel and logistic regression methods were used to compare HIV-positive and HIV-negative female youth. RESULTS: Younger injectors (N = 232) were more likely to be female; work in the sex trade; report condom use; inject heroin daily; smoke crack cocaine daily; and need help injecting. HIV prevalence at baseline among the youth was 10%. HIV prevalence was associated with female gender; history of sexual abuse; engaging in survival sex; injecting heroin daily; injecting speedballs (a mixture of heroin and cocaine) daily; and having numerous lifetime sexual partners. CONCLUSION: Our data show that HIV positivity among young IDUs is concentrated among females engaged in dual sexual and drug-related risk exposure categories. Over half the HIV-positive youth were Aboriginal (a classification used by the federal government in Canada to include native peoples of all ethnic groups). Targeted interventions that take into account sexual and drug risk for young female and Aboriginal peoples are urgently needed.

Adolescent↗
PubMed2004

Evaluation of a triple sugar test of colonic permeability in humans.

AIM: Conventional dual sugar tests of intestinal permeability assess only the stomach and small intestine. A novel triple sugar method of assessing colonic permeability has recently been described in animals. This utilizes the non-fermented sweetener sucralose, in addition to conventional sugars. It has been postulated that this test enables the simultaneous assessment of small-intestinal and colonic barrier function in humans. The aim of this study was to evaluate the triple sugar test using healthy volunteers and ileostomists. METHODS: Twenty-one healthy volunteers and 18 ileostomists underwent the triple sugar test. After an overnight fast, subjects drank a solution containing lactulose (5 g), rhamnose (1 g) and sucralose (5 g). Urine was collected for 0-5 h and 5-19 h. Urinary sugars were quantified using HPLC, and 5 and 24-h excretion calculated. Nineteen control subjects and 16 ileostomists also underwent a 51Cr-EDTA permeability test. Permeability data were presented as medians (IQR), and differences between groups analysed with Mann-Whitney U-tests. RESULTS: Lactulose excretion and the 5-h lactulose/rhamnose (L/R) ratio were similar in controls and ileostomists [L/R ratio 0.024 (0.022-0.034) vs. 0.025 (0.022-0.035), P = 0.955]. Twenty-four hours excretion of sucralose was significantly higher in control subjects compared with ileostomists [1.41% (1.17-1.68) vs. 0.96% (0.64-1.2), P = 0.003]. The same pattern was seen with 51Cr-EDTA [2.73% (2.06-3.76) vs. 2.06% (1.55-2.71), P = 0.037] and with lactulose [0.52% (0.42-0.60) vs. 0.25% (0.16-0.35), P = 0.002]. CONCLUSIONS: Both sucralose and 51Cr-EDTA underwent significant colonic absorption. A significant amount of lactulose also appeared to be absorbed in the colon. This unexpected finding requires further study.

Adult↗
PubMed2004

Nationwide HIV prevalence survey in general population in Niger.

A national population-based survey was carried out in Niger in 2002 to assess HIV prevalence in the population aged 15-49 years. A two-stage cluster sampling was used and the blood specimens were collected on filter paper and tested according to an algorithm involving up to three diagnostic tests whenever appropriate. Testing was unlinked and anonymous. The refusal rate was 1.1% and 6056 blood samples were available for analysis. The adjusted prevalence of HIV was 0.87% (95% CI, 0.5-1.3%) and the 95% CI of the estimated number of infected individuals was 22 864-59 640. HIV-1 and HIV-2 represented, respectively, 95.6% and 2.9% of infections while dual infections represented 1.5%. HIV positivity rate was 1.0% in women and 0.7% in men. It was significantly higher among urban populations than among rural ones (respectively, 2.1% and 0.6%, P < 10(-6)). Using logistic regression, the variables significantly related to the risk of being tested positive for HIV were urban housing, increasing age and being either widowed or divorced. The estimate from the national survey was lower than the prevalence assessed from antenatal clinic data (2.8% in 2001). In the future, the representativeness of sentinel sites should be improved by increasing the representation of rural areas accounting for more than 80% of the population. Compared with other sub-Saharan countries, the HIV prevalence in Niger is still moderate. This situation represents a strong argument for enhancing prevention programmes and makes realistic the projects promoting an access to potent antiretroviral therapies for the majority.

Adolescent↗
PubMed2005

History of attention-deficit hyperactivity disorder symptoms and opioid dependence: a controlled study.

The co-occurrence of attention-deficit hyperactivity disorder (ADHD) and substance use disorders has received considerable attention in recent clinical and scientific investigations. These two disorders are linked to one another in a variety of ways. The core symptoms of ADHD may be mimicked by the effects of psychoactive substance use, making it difficult to diagnose one disorder in the presence of the other. Individuals with ADHD may demonstrate earlier onset of the substance abuse and a pattern of more frequent or intense use. ADHD symptoms were explored as possible antecedents of opioid dependence. A total of 109 adult opioid-dependent, treatment-seeking male and female outpatients were investigated with an extended clinical semistructured interview to collect sociodemographic, drug-related, and clinical data. The results indicate that ADHD alone does not predispose the development of opioid dependence in our sample. Childhood ADHD symptoms may nevertheless be found more frequently related to school performance problems and difficulties in social adaptation, which was identified in more than half of our population. Patients with ADHD history seemed to experience a drug abuse career with more complications which need to be recognized with focused attention in order to start earlier treatment strategies.

Adolescent↗
PubMed1998

Complications of dual chamber pacemaker implantation in the elderly. Pacemaker Selection in the Elderly (PASE) Investigators.

Pacemakers are frequently implanted, yet accurate prospective data on implant complications are limited. Elderly patients may be at increased risk of implant complications and are increasingly being referred for pacemaker implantation. The purpose of the present analysis was to define the incidence and possible predictors of serious complications of dual chamber permanent pacemaker implantation in the elderly. Therefore, we sought to prospectively identify the incidence and predictors of pacemaker implant complications in a large multicenter trial involving patients receiving a dual chamber pacemaker. The Pacemaker Selection in the Elderly (PASE) study was a prospective trial designed to evaluate quality of life in dual chamber pacemaker recipients age 65 years or older randomized to DDDR versus VVIR programming. In addition to being age 65 years or older, patients enrolled in this study were in normal sinus rhythm, and had standard indications for permanent pacemaker implantation. All patients received dual chamber pacemakers and were randomized to DDDR versus VVIR pacing. Pacemaker implant complications were collected on standardized forms which were completed at pacemaker implantation and during follow-up appointments. In this study of 407 patients, there were 26 complications occurring in 25 patients (6.1%). The most frequent complication was lead dislodgment which occurred in 9 patients. This was followed by pneumothorax (8 patients) and cardiac perforations (4 patients). In 18 patients (4.4%) repeat surgical procedures (including chest tubes) were required. Complications were noted prior to discharge in only 18 patients. There were no significant predictors of overall complications. Pneumothorax was more frequent in patients > or = 75 years old, and was observed only in patients with subclavian venous access. In conclusion, complications from pacemaker implantation in the elderly are seen in 6.1% of patients and 4.4% of patients require a repeat surgical procedure. Other than advanced age and lower weight predicting for pneumothorax, there are no significant clinical predictors of complications.

Age Factors↗
PubMed1994

Imaging in the far-red with electronic light microscopy: requirements and limitations.

The acquisition of simultaneous dual confocal images with red and far-red light has both advantages (e.g. lower autofluorescence) and limitations. An understanding of these requisites is necessary to acquire high-quality images and to avoid the misinterpretation of experimental data. The poor detection of far-red light mandates a high optical transfer efficiency for the system, thus the transmittance of the objective lens and its axial and lateral chromatic aberration in the far-red are important factors for consideration. This technical note is an attempt to 'demystify' the process of filter set design for confocal microscopy by discussing the considerations that went into the construction of a filter set for use with the reagents cyanine 3.18 (Cy3) and cyanine 5.18 (Cy5), and thus to encourage users to look beyond the multi-purpose designs available commercially. The 568-nm laser line exciting Cy3 is at its emission maximum, which limits the collectable Cy3 fluorescence. High-transmission optical filters with sharp band pass cutoffs are thus desirable for maximum light throughout. Light path mirror efficiency rapidly degrades above 700 nm, but the loss of this portion of the Cy5 emission spectrum is acceptable since the fluorophore is very bright, and these very long wavelengths are also likely to introduce aberration. While resolution is decreased with far-red light, there is also greater penetration and less scattering, and it is thus possible to obtain high-quality images from deeper within the specimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbocyanines↗
PubMed2004

Experimental analysis of critical oxygen delivery.

Systemic variables were evaluated with respect to O(2) delivery to test the hypothesis that critical O(2) delivery and critical Hb can be estimated by multiple variables collected simultaneously. Rats were subjected to transfusion with either fresh or stored blood and then subjected to stepwise isovolemic hemodilution. Critical levels were measured by the dual-regression method from plots of systemic variables against O(2) delivery and Hb. Delivery was calculated from cardiac index and arterial O(2) content. We found that 1) after hemodilution, O(2) delivery changed in a nonlinear relationship with Hb; 2) critical delivery calculated using 30 different systemic variables was not statistically different from each other; 3) critical delivery and critical Hb were correlated but were not different between animals receiving fresh or stored blood; and 4) similar critical levels were found using a single variable from several animals and using several variables from the same subject. The best variables to estimate critical delivery were lactate, bicarbonate, base excess, O(2) extraction ratio, expired CO(2), pulse pressure, cardiac index, and systolic pressure. The data suggest that a multivariable analysis of critical delivery may help determine the physiological oxygenation boundary at the whole body level. This may assist in finding therapeutic triggers on an individual basis using systemic markers of the transition from aerobic to anaerobic metabolism.

Animals↗
PubMed2004

Relationship among MRTA, DXA, and QUS.

Dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) are the accepted modalities for the evaluation of fracture risk in the clinical setting. However, neither method provides a direct measurement of bone mechanics. In this study, we investigated a prototype device, known as a mechanical response tissue analyzer (MRTA), which provides direct mechanical measurements of mechanical properties of bone. A total of 56 healthy volunteers (20 men and 36 women) between the ages of 18 and 83 were recruited. The MRTA was used to measure the cross-sectional bending stiffness (EI) of the ulna bone. Axial speed of sound (SOS) at the ulna bone was determined by QUS; bone mineral content (BMC) and bone mineral density (BMD) were determined by DXA. Correlations, regression analysis, and analyses of variance (ANOVAs) were used to compare the three modalities. These analyses revealed that although there are strong linear relationships among the data collected by the various technologies, the bone properties reflected by MRTA are not fully explained by DXA and QUS. We conclude that the total information conveyed by MRTA measurements is unique. Further research is needed to delineate the different qualities of bone strength that are captured by MRTA, but not by DXA or QUS.

Absorptiometry, Photon↗
PubMed2003

Dual influence of aldosterone on AQP2 expression in cultured renal collecting duct principal cells.

In the renal collecting duct (CD) the major physiological role of aldosterone is to promote Na+ reabsorption. In addition, aldosterone may also influence CD water permeability elicited by vasopressin (AVP). We have previously shown that endogenous expression of the aquaporin-2 (AQP2) water channel in immortalized mouse cortical CD principal cells (mpkCCDC14) grown on filters is dramatically increased by administration of physiological concentrations of AVP. In the present study, we investigated the influence of aldosterone on AQP2 expression in mpkCCDC14 cells by RNase protection assay and Western blot analysis. Aldosterone reduced AQP2 mRNA and protein expression when administered together with AVP for short periods of time (< or =24 h). For longer periods of time, however, aldosterone increased AQP2 protein expression despite sustained low expression levels of AQP2 mRNA. Both events were dependent on mineralocorticoid receptor occupancy because they were both induced by a low concentration of aldosterone (10-9 m) and were abolished by the mineralocorticoid receptor antagonist canrenoate. Inhibition of lysosomal AQP2 protein degradation increased AQP2 protein expression in AVP-treated cells, an effect that was potentiated by aldosterone. Finally, both aldosterone and actinomycin D delayed AQP2 protein decay following AVP washout, but in a non-cumulative manner. Taken together, our data suggest that aldosterone tightly modulates AQP2 protein expression in cultured mpkCCDC14 cells by increasing AQP2 protein turnover while maintaining low levels of AQP2 mRNA expression.

Aldosterone↗
PubMed2002

Hepatitis B genotypes and precore/basal core promoter mutants in HBeAg-negative chronic hepatitis B.

BACKGROUND: Mutations in the precore stop codon (G1896A) and the basal core promoter (A1762T and G1764A) are frequently found in hepatitis B envelope antigen (HBeAg)-negative chronic hepatitis B. However, the clinical significance of these mutations remains controversial. We therefore investigated the influence of hepatitis B virus (HBV) genotypes, as well as precore/basal core promoter mutants, on the clinical and virological features of patients with HBeAg-negative chronic hepatitis B. METHODS: Serum samples from 37 patients with HBeAg-negative chronic hepatitis B were collected for serological and molecular assays. The precore and basal core promoter regions were amplified by polymerase chain reaction and the amplicons were directly sequenced and analyzed. HBV genotype was determined by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Most of the patients had detectable serum HBV DNA, and genotypes B and C were the predominant strains. The overall prevalence of the precore stop codon mutant and basal core promoter mutant was 67% and 60%, respectively. The baseline clinical and virological features of patients with genotype B and genotype C infection were comparable. However, in the patients with precore/basal core promoter dual mutations there was a significantly lower proportion of individuals with a high detectable serum HBV DNA level (>100pg/ml) than in the patients with either the precore stop codon mutation alone or the basal core promoter mutation alone (P = 0.04 by the logistic regression test for the trend). CONCLUSIONS: Our data suggest a high prevalence of precore stop codon and basal core promoter mutation in Taiwanese patients with HBeAg-negative chronic hepatitis B, and the influence of the basal core promoter mutation on HBV replication is modulated by the emergence of the precore stop codon mutation.

Adolescent↗
PubMed2007

Structural evidence for a new IgG1 antibody sequence allele of cattle.

Analysis of the heavy-chain gene (pTGHC9907) encoding a bovine IgG1 antibody against bovine herpes virus type 1 (BHV-1) isolated from a Holstein cow has led to the identification of a new IgG1 sequence allele. A comparison of nucleotide sequence of pTGHC9907 with the IgG1(a) (clone 2) and IgG1(b) (clone 8.10) sequence variants and unclassified IgG1 cDNA sequence (clone 8.75) has revealed significant differences in the hinge region spanning codons 216-230. The Thr224 and Thr226 of IgG1(a) were replaced with Arg224 and Pro226, while both Thr218 and Pro224 of IgG1(b) were substituted with Arg with deletion of Ser225 in HB9907 antibody. Additional amino acid substitutions were noted in the CH1 (positions 190, 192), CH2 (position 281) and CH3 (position 402) exons. Thus, the polymorphic sites occurred in all constant domains, but were clustered in the hinge region of IgG1. Examination of a three-dimensional model of the HB9907 heavy chain revealed that all sequence variations were on the surface of the IgG and are possible targets for recognition by antisera and effector molecules such as cellular adhesion molecules. The presence in the CH1 domain of a repeating motif of Pro-Ala-Ser-Ser indicated a potential structure-enhancing function and a role in cellular adhesion and migration. Replacement of Thr with Arg residues within the hinge was predicted to have a dual effect of reducing the number of O-linked glycosylation sites and increasing the susceptibility to degradation by protease-secreting bacteria of the hinge region. As unclassified IgG1 cDNA sequence (clone 8.75) is structurally distinct from other variants, it is also classified as IgG1(d). Collectively, these observations support the identification of a new allotypic variant of bovine IgG1, designated as IgG1(c) that is distinct in both sequence and structure from the known sequence variants.

Alleles↗
PubMed2003

Ex situ inhibition of hepatic uptake and efflux significantly changes metabolism: hepatic enzyme-transporter interplay.

The disposition of digoxin and the influence of the organic anion transporting polypeptide (Oatp)2 inhibitor rifampicin and the P-glycoprotein (P-gp) inhibitor quinidine on its hepatic disposition were examined in the isolated perfused rat liver. Livers from groups of rats were perfused in a recirculatory manner after a bolus dose of digoxin (10 microg), a dual substrate for Oatp2 and P-gp as well as CYP3A. Perfusions of digoxin were also examined in groups of rats in the presence of the inhibitors: rifampicin (100 microM) or quinidine (10 microM). In all experiments, perfusate samples were collected for 60 min. Digoxin and its primary metabolite were determined in perfusate and liver by liquid chromatography/mass spectrometry. The area under the curve (AUC) from 0 to 60 min was determined. The AUC +/- S.D. of digoxin was increased from control (3880 +/- 210 nM x min) by rifampicin (5200 +/- 240 nM x min; p < 0.01) and decreased by quinidine (3220 +/- 340 nM x min; P < 0.05). It is concluded that rifampicin limits the hepatic entrance of digoxin and reduced the hepatic exposure of digoxin to CYP3A by inhibiting the basolateral Oatp2 uptake transport, whereas quinidine increased the hepatic exposure of digoxin to CYP3A by inhibiting the canalicular P-gp transport. These data emphasize the importance of uptake and efflux transporters on hepatic drug metabolism.

Animals↗
PubMed2004

Results of catheter ablation of typical atrial flutter.

The purpose of this study was to evaluate the safety and efficacy of radiofrequency (RF) ablation of typical atrial flutter by using an 8-mm electrode catheter and a 100-W RF power generator. A limitation of previous trials of catheter ablation of atrial flutter is that the data were not collected as part of a prospective multicenter clinical trial. The study results associated catheter ablation of typical atrial flutter in a cohort of 150 patients with an 88% acute efficacy rate. At 6-month follow-up, recurrent typical atrial flutter was observed in 13% of patients. Of the 12 patients with typical atrial flutter recurrence, 4 were symptomatic and 8 were asymptomatic. Procedure duration was a significant predictor of typical atrial flutter recurrence. The 12-month rate for development of atrial fibrillation was 30%. Catheter ablation of atrial flutter was associated with significant improvements in 5 of 8 domains of the Short Form 36 Survey (quality of life) and significant decreases in 13 of the 16 symptoms of the Symptom Checklist. The device- or procedure-related complication rate was 2.7%. Skin burns occurred at the dispersive pad site due to stronger RF power in 3 patients. Use of a dual dispersive pad system mitigated this problem. Thus, the results of this study associated catheter ablation of atrial flutter with high acute efficacy, a small risk of recurrent atrial flutter, and an important risk of atrial fibrillation during follow-up.

Aged↗
PubMed1988

Dual role of glucocorticoids in regulation of pituitary content and secretion of gonadotropins.

To verify the inhibitory effect of cortisol (F) on secretion of luteinizing hormone (LH) 24 h postorchidectomy, we implanted cholesterol (C) or F subcutaneously into male rats, and 4 days later orchidectomized or sham orchidectomized them under ether anesthesia. We injected gonadotropin-releasing hormone (GnRH) or saline into these rats 24 h postorchidectomy, collected blood 30 min later, and measured LH and follicle-stimulating hormone (FSH) in serum and pituitaries. F inhibited GnRH-induced secretion of LH without affecting secretion of FSH. We then implanted C, corticosterone (B), or F into rats, performed the same surgeries, and collected pituitaries 24 h after surgery for quantitation of receptors for GnRH. Neither F nor B affected the number of receptors for GnRH or their affinity for a GnRH analogue. Suppression of LH in serum occurred without decreased pituitary content of LH. In contrast, F increased pituitary content of FSH. Implantation of progesterone in a similar experiment did not affect circulating concentrations or pituitary contents of FSH or LH. These data suggest that glucocorticoids may inhibit responsiveness to GnRH by some mechanism distal to the receptor for GnRH that affects only LH.

Animals↗