Aortic valve calcium score: does it correlate with mean transaortic gradient?

Introduction

Aortic valvular calcium score (AVCS) is useful in patients with aortic stenosis for whom echocardiography was not conclusive in grading its severity. Transcatheter aortic valve implantation (TAVI) is an established procedure of treatment in symptomatic severe AS. The burden of aortic valve calcification has been associated with some TAVI related complications (as perivalvular leaks), but at the same time it is well accepted that some degree of calcification is needed to ensure stable anchoring of the prosthesis to the aortic annulus.

Purpose

To assess if there is a correlation between aortic valve calcium score and mean transvalvular gradient 6 months after TAVI – is a higher AVCS correlated with lower mean transaortic gradient after TAVI?

Methods

We performed a single-center, retrospective cohort study including patients who underwent TAVI with a preoperative standardized contrast enhanced MSCT with AVCS available. Clinical and echocardiographic data were collected previously to TAVI (pre-TAVI) and at 6 months follow up (6M-FUP).

Results

A total of 187 patients were included, with 54% female and a mean age of 79.4±9.0 years old. Most patients had tricuspid aortic valve (95.7%); 5 patients had aortic bicuspidy and 3 had aortic valve bioprothesis. Concerning the valve type, 73.3% had new generation prosthesis and the main valve used was the CoreValve Evolut Pro (33.7%). Also, 38,5% needed balloon pre-dilation before TAVI. The mean pre-TAVI aortic transvalvular maximum and mean gradients were 76.5±23.2 mmHg and 48.3±15.5 mmHg, respectively; mean aortic valve area was 0.75±0.16 cm2. The mean AVCS was 2851±1524 AU (Agaston Units); 81.2% of women had AVCS>1300 AU and 74.4% men had AVCS >2000 AU. Comparing transvalvular aortic gradients previously and 6M-FUP after TAVI, there was an average differential of maximum gradient of 61±22 mmHg and of mean gradient of 40±15 mmHg. A negative and weak correlation was found between the AVCS and the maximum gradient (pearson coefficient of −0.181, p=0.02) and between mean gradient at 6M-FUP (pearson coefficient of −0.191, p=0.014).

Discussion and conclusion

AVCS is a significant predictor for death, stroke and perivalvular leaks after TAVI. On the other hand, high AVCS is associated with better seating in the native annulus during deployment. Nevertheless, high AVCS did not strongly correlated with mean transaortic gradient 6 months after TAVI.

Funding Acknowledgement

Type of funding sources: None.

Reduced 3D-left atrium ejection fraction predicts development of atrial fibrillation in patients with hypertrophic cardiomyopathy

Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), occurring in approximately 25% of patients, related to left atrial (LA) dilatation and remodeling. HCM patients who develop AF have increased risk of HCM-related death, functional impairment, and stroke. Accurate risk stratification for AF in this population is crucial as contemporary treatments are highly successful.

Purpose

To assess if new echocardiographic parameters can predict the development of AF in HCM patients.

Methods

HCM patients who underwent comprehensive echocardiographic examination during 2011 were followed and checked for “de novo” AF until November 2021. We searched for associations between AF development and novel echocardiographic parameters such as LA Volume index, Left Atrioventricular Coupling Index (LACI, as LAVI/a'), 3D LA volumes and 3D LA ejection fraction (3D-LAEF).

Results

A total of 43 patients were included, with 62.8% male and mean age 56,1±6,2 years old. 55.8% had the septal asymmetric HCM type and mean LV mass was 326±127g. Mean LA diameter and biplane 2D volume was 46±7 mm and 78±37 mL, respectively. 11.6% of patients already had AF. During a median follow-up of 9.4 years, the incidence of “de novo” AF was 31,6%. Within the total 17 patients with AF, 35,2% took warfarin and the remaining direct oral anti-coagulation. No stroke was documented. There were 3 deaths (mortality rate of 7,0%), none from cardiac causes.

No association was found between AF development and LAVI, LACI or 3D LA volumes. We only found a statistically significant difference regarding 3D-LAEF, which was lower in patients who developed AF compared with those without AF (26±12% VS 39±19%, p=0.04).

Binary logistic regression analysis found that reduced 3D-LAEF predicts the development of AF (p=0.019, odds ratio [OR] 2.6, 95% confidence interval [CI] 1.0 to 1.1). The area under a receiver operating characteristic curve using 3D-LAEF as a predictive marker for AF development in HCM patients was 0.743 (p=0.004). When the cut-off value of 3D-LAEF was set at 34,5%, the sensitivity and specificity for AF diagnosis were 66% and 86%, respectively.

Conclusion

In our study, 3D LAEF predicted the development of AF in HCM patients – this may be a useful tool to identify patients at high risk of future AF who may benefit from more intensive rhythm monitoring and a lower threshold for oral anticoagulation.

Funding Acknowledgement

Type of funding sources: None.

20 year-follow up of mitral stenosis patients after percutaneous valve commissurotomy: moderate disease of other valves as predictor for re-intervention

Background

Percutaneous valve commissurotomy (PMC) is a viable alternative to mitral valve (MV) surgery in the treatment of patients with clinically significant mitral stenosis (MS). About 40% of patients treated with PMC will require at least one reintervention (either PMC or MVS) along time.

Purpose

To evaluate the long-term results of PMC in patients with rheumatic MS.

Methods

We retrospectively analysed all consecutive patients between 1991 and 2008 with clinically significant rheumatic MS undergoing PMC. Clinical and echocardiographic data were collected at baseline and during early and long-term follow-up. MACE was a composite of adverse events defined as all-cause mortality, MV re-intervention or cardiovascular hospitalization.

Results

A total of 124 patients were enrolled: 108 (87%) were female, with a mean age at the time of PMC of 46±11 years.

At baseline, 34% patients were in NYHA class ≥ III and 81% had a Wilkins score ≤8; all patients had preserved biventricular systolic function and 83% presented pulmonary hypertension. Regarding associated valve disease, 46 patients had mild tricuspid regurgitation (TR), 19 mild aortic regurgitation (AR), 14 moderate IT and 5 moderated AR.

Most of the procedures were successful (91%) and without complications (94%), with median improvement in MV area of 0.9 cm2 (IQR 0.5) and median reductions in mean transmitral gradient (MTG) of 6 mmHg (IQR 6) and in pulmonary artery systolic pressure (PASP) of 8 mmHg (IQR 10) early after PMC.

During the mean follow-up of 20±6 years, 52 (42%) of patients had MV re-intervention (86% surgery and 14% re-PMC), 37 (30%) were hospitalized and 30 (24%) died. Concerning time-to-event analysis, approximately 80% of patients kept MACE-free after 10 years; after 30 years, more than 20% continued MACE-uneventful, approximately 50% were alive and about 45% were free from re-intervention.

Considering patients submitted to surgical re-intervention, 9 underwent MV valvuloplasty and the others MV replacement with mechanical (32) or biological prothesis (11). At the same procedure, 23 patients were submitted to tricuspid annuloplasty, 9 to other valve replacement and one to coronary artery bypass graft.

Using Cox regression, we found that the presence of moderate disease of other valves at PMC time was associated with a 2.3-fold greater rate of re-intervention compared to patients with none or mid disease of other valves (HRcrude 2.3; 95% IC 1.221–4.331, p=0.017). After adjusting for the success of the PMC and for mitral regurgitation after PMC, the observed effect remained significant (HRadjusted = 2.7; 95% CI 1.417–5.233, p=0.003).

Conclusion

PMC was safe and effective in clinically significant rheumatic MS. Most of the patients were free from adverse events after 10 years and half were alive after 30 years. Still, about 40% required re-intervention, with moderate disease of other valves as its independent predictor.

Funding Acknowledgement

Type of funding sources: None.

Aortic valve calcium score and peri-prothesis leaks after transcatheter aortic valve implantation: a hint?

Funding Acknowledgements

Type of funding sources: None.

Introduction

The first-line evaluation of aortic stenosis (AS) severity is Doppler echocardiography. Aortic valvular calcium score (AVCS) measured by tomography scans (TS) is useful in patients for whom echocardiography is not conclusive. For high-risk patients with symptomatic severe AS, transcatheter aortic valve implantation (TAVI) is an established procedure of treatment. The burden of aortic valve calcification has been associated with some TAVI related complications. Peri-prothesis leaks (PPL) are an important complication that may compromise TAVI net results and further refinements are required to predict high-risk patients.  Purpose: To access if there is an association between aortic valve calcium score and moderate to severe (mod-sev) peri-prothesis leaks immediately and 6 month after TAVI.  Methods: We performed a single-center, retrospective cohort study including patients who underwent TAVI with a preoperative standardised TS with AVCS available. Clinical and echocardiographic data were collected previously to TAVI (pre-TAVI) and at 6 months follow up (6M-FUP).  Results: A total of 187 patients were included, with 54% female and a mean age of 79.37± 9.029 year-old. Most patients had tricuspid aortic valve (95.7%); 5 patients had aortic bicuspidy and 3 had aortic valve bioprothesis. Considering left ventricular systolic function, the majority had conserved function (73.0%), the remaining had mild (9.7%), moderate (11.4%) or severe (5.9%) dysfunction.  Concerning the valve type, 73.3% had new generation prosthesis and the main valve used was the CoreValve Evolut Pro (33.7%). Also, 38.5% patients underwent balloon valve pre-dilation before implantation. In-hospital mortality was 2.7%. At 6M-FUP, 8 of 182 patients had dead.  The mean AVCS was 2851 ± 1524 AU (Agaston Units); 81.2% of women had AVCS > 1300 AU and 74.4% men had AVCS >2000 AU.  Comparing AVCS with the presence or absence of moderate to severe peri-prothesis leaks, no statistically significant difference was found immediately (no vs mod-sev leak, AS: 2758 ± 2308 vs 3621 ± 1376, p= 0,13) and 6 months after the procedure (no vs mod-sev leak, AS: 2892 ± 2366 vs 3621 ± 1424, p = 0.15). Considering earlier (Portico, CoreValve Evolut R) vs newer valves (CoreValve Evolut Pro; Edward Sapiens 3; Accurate Neo), there was no statistically significant difference relating AVCS and PPL; however, in patients who had newer valves there was a trend to higher AVCS and moderate to severe leaks, both on the immediate (no vs mod-sev leak, AS: 2777 ± 2507 vs 3601 ± 1385, p = 0.07) and at 6 months (no vs mod-sev leak, AS: 2782 ± 2506 vs 3984 ± 1138, p = 0.06). No statistically significant difference was found when comparing pre-ballooning dilatation. Conclusion: Aortic calcium measured by Agatston score did not show an association with new moderate to severe peri-valvular leaks after TAVI. Nevertheless, it seems to be a trend for higher AS and moderate to severe peri-prothesis leaks when newer valves are implanted.

Impact of severe mitral annular calcification on mitral regurgitation after transcatheter aortic valve implantation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Transcatheter aortic valve implantation (TAVI) has become the standard of care treatment in patients with severe aortic stenosis who are at intermediate or high risk for surgical aortic valve replacement. Mitral annular calcification (MAC) is frequent in patients with aortic stenosis, and its presence is associated with increased cardiovascular morbidity and mortality. Not infrequently, it is associated with significant morphologic and functional abnormalities of the mitral valve apparatus.

Purpose

 The aim of this work is to evaluate the relationship between severe MAC and the presence and development of significant mitral regurgitation after TAVI.

Methods

 We retrospectively analyzed all patients who underwent TAVI at a tertiary center from October 2014 to November 2019. Clinical, echocardiographic and procedure-related data were collected until a follow-up of 6 months. Statistical analysis was conducted on IBM SPSS® Statistics software. Descriptive statistics were calculated for all variables. Sample T-test, Chi-square and Wilcoxon sign test were used. A p-value < 0.05 was considered significant. The presence and severity of MAC was defined according to echocardiographic data. Severe MAC was defined by the presence of calcification of more than half of the mitral annular circumference.

Results

 A total of 343 patients were enrolled in the study. The mean age of the population was 80 ± 8 years, 45% were male. Mean functional area was 0.75 ± 0.18 cm2, mean transvalvular pressure gradient was 48 ± 15 mmHg and the mean left ventricular ejection fraction (LVEF) was 54 ± 14%.  MAC was detected in 231 (67%) patients. In 44 (19%) of these patients, MAC was graded as severe. Patients with severe MAC tended to have higher prevalence of moderate (27.3 vs 20.4%, p = 0.30) as well as severe (4.5 vs 1.8%, p = 0.24) mitral regurgitation at baseline. After TAVI, the prevalence of moderate mitral regurgitation at 6 months was similar between both groups (22.5 vs 20.4%, p = 0.76). Although not reaching statistical significance, patients with severe MAC had higher prevalence of severe mitral regurgitation at 6 months post-procedure (12.2 VS 5.0%, p = 0.07) as well as higher incidence of worsening of mitral regurgitation (34.2 vs 23.7%, p = 0.16). The proportion of patients that had improvement (13.2 vs 15.0%, p = 0.76) or no change (52.6 vs 61.3%, p = 0.31) in the degree of mitral regurgitation was similar in both groups. 

Conclusion

 The presence of severe MAC at baseline echocardiography in patients undergoing TAVI may be associated with worsening of mitral regurgitation after the procedure. These patients tend to have higher prevalence of severe mitral regurgitation post-TAVI. Further studies are needed in order to further elucidate this association.

Can aortic calcium score predict new conduction disturbances in pos-transcatheter aortic valve implantation?

Funding Acknowledgements

Type of funding sources: None.

Background

Transcatheter aortic valve implantation (TAVI) may be the first line treatment for severe aortic stenosis according to overall patient characteristics. Semi-quantitative Agatston score (AS), which quantifies aortic calcium by cardiac computed tomography (CCT), has knowledgeable practical and clinical implications, and is performed in TAVI diagnostic workup. Since conduction disturbances continue to be the most frequent complication, further refinements are required to predict high-risk patients.

Purpose

To access if aortic AS relates with new conduction disturbances and permanent pacemaker (PPM) implantation in patients undergoing TAVI.

Methods

We retrospectively analyzed all patients who underwent TAVI at a tertiary center from October 2014 to November 2019; patients with previous permanent pacemaker (PPM) or had no aortic AS were excluded. Clinical and electrocardiogram (ECG) data were collected at admission and after the procedure. All categorical variables are reported as numbers and percentages. Continuous variables were analyzed using the two-tailed unpaired Student’s t-test and are reported as mean values and the standard deviation. Statistical analysis was performed using the IBM SPSS.

Results

172 patients with a mean age 79 ± 9.1 years old were included (see table 1 for baseline characteristics). AS was on average 3008 ± 2262 (see table 2 for remaining diagnostic workup and procedure characteristics).

Comparing AS with new conduction disturbances, no statistically significant difference was found for new complete left branch block (LBBB) (no vs new LBBB, AS: 3179 ± 2555 vs 2637 ± 1388, p= 0,15) and with new complete atrioventricular block (AVB) (no vs new AVB, AS: 2834 ± 1520 vs 4485 ± 5285, p = 0.2). Considering PPM implantation after TAVI, there was a tendency for higher AS and PPM implantation (no vs PPM implantation, AS: 2756 ± 1451 vs 4242 ± 4310, p = 0.07).

In patients who had pre-ballooning, there was no difference relating to AS; however, in patients who had no pre-ballooning there was a trend to higher AS and PPM implantation (no vs PPM implantation, AS: 2417 ± 1301 vs 4616 ± 4969, p = 0.06). No statistically significant difference was found when comparing earlier (Portico, CoreValve Evolut R) vs newer valves (CoreValve Evolut Pro; Edward Sapiens 3; Accurate Neo).

Conclusion

Aortic calcium measured by Agatston score did not show a correlation with new LBBB or new AVB after TAVI. Nevertheless, it seems to be a trend for higher AS and PPM implantation; this was more noticeable when pre-ballooning was not performed. Further studies are needed in order to further elucidate this association. Abstract Figure. Patients baseline characteristics  Abstract Figure. TAVI diagnostic workup and procedure

Modelling and treating GRIN2A developmental and epileptic encephalopathy in mice

NMDA receptors play crucial roles in excitatory synaptic transmission. Rare variants in GRIN2A encoding the GluN2A subunit are associated with a spectrum of disorders, ranging from mild speech and language delay to intractable neurodevelopmental disorders, including but not limited to developmental and epileptic encephalopathy. A de novo missense variant, p.Ser644Gly, was identified in a child with this disorder, and Grin2a knock-in mice were generated to model and extend understanding of this intractable childhood disease. Homozygous and heterozygous mutant mice exhibited altered hippocampal morphology at 2 weeks of age, and all homozygotes exhibited lethal tonic-clonic seizures by mid-third week. Heterozygous adults displayed susceptibility to induced generalized seizures, hyperactivity, repetitive and reduced anxiety behaviours, plus several unexpected features, including significant resistance to electrically-induced limbic seizures and to pentylenetetrazole induced tonic-clonic seizures. Multielectrode recordings of neuronal networks revealed hyperexcitability and altered bursting and synchronicity. In heterologous cells, mutant receptors had enhanced NMDA receptor agonist potency and slow deactivation following rapid removal of glutamate, as occurs at synapses. NMDA receptor-mediated synaptic currents in heterozygous hippocampal slices also showed a prolonged deactivation time course. Standard anti-epileptic drug monotherapy was ineffective in the patient. Introduction of NMDA receptor antagonists was correlated with a decrease in seizure burden. Chronic treatment of homozygous mouse pups with NMDA receptor antagonists significantly delayed the onset of lethal seizures but did not prevent them. These studies illustrate the power of using multiple experimental modalities to model and test therapies for severe neurodevelopmental disorders, while revealing significant biological complexities associated with GRIN2A developmental and epileptic encephalopathy.

Arfgef1 haploinsufficiency in mice alters neuronal endosome composition and decreases membrane surface postsynaptic GABAA receptors

ARFGEF1 encodes a guanine exchange factor involved in intracellular vesicle trafficking, and is a candidate gene for childhood genetic epilepsies. To model ARFGEF1 haploinsufficiency observed in a recent Lennox Gastaut Syndrome patient, we studied a frameshift mutation (Arfgef1^fs) in mice. Arfgef1^fs/+ pups exhibit signs of developmental delay, and Arfgef1^fs/+ adults have a significantly decreased threshold to induced seizures but do not experience spontaneous seizures. Histologically, the Arfgef1^fs/+ brain exhibits a disruption in the apical lining of the dentate gyrus and altered spine morphology of deep layer neurons. In primary hippocampal neuron culture, dendritic surface and synaptic but not total GABA_A receptors (GABA_AR) are reduced in Arfgef1^fs/+ neurons with an accompanying decrease in the number of GABA_AR-containing recycling endosomes in cell body. Arfgef1^fs/+ neurons also display differences in the relative ratio of Arf6⁺:Rab11⁺:TrfR⁺ recycling endosomes. Although the GABA_AR-containing early endosomes in Arfgef1^fs/+ neurons are comparable to wildtype, Arfgef1^fs/+ neurons show an increase in the number of GABA_AR-containing lysosomes in dendrite and cell body. Together, the altered endosome composition and decreased neuronal surface GABA_AR results suggests a mechanism whereby impaired neuronal inhibition leads to seizure susceptibility.

Distinct roles for REV-ERBα and REV-ERBβ in oxidative capacity and mitochondrial biogenesis in skeletal muscle

The nuclear receptors REV-ERBα and REV-ERBβ have been demonstrated to be core members of the circadian clock and participate in the regulation of a diverse set of metabolic functions. Due to their overlapping tissue expression patterns and gene expression profiles, REV-ERBβ is thought to be redundant to REV-ERBα. Recent work has highlighted REV-ERBα's role in the regulation of skeletal muscle oxidative capacity and mitochondrial biogenesis. Considering the similarity between the REV-ERBs and the hypothesized overlap in function, we sought to determine whether REV-ERBβ-deficiency presented with a similar skeletal muscle phenotype as REV-ERBα-deficiency. Ectopic overexpression in C2C12 cells demonstrated that REV-ERBβ drives mitochondrial biogenesis and the expression of genes involved in fatty acid oxidation. Intriguingly, knock down of REV-ERBβ in C2C12 cultures also resulted in mitochondrial biogenesis and increased expression of genes involved in fatty acid β-oxidation. To determine whether these effects occurred in vivo, we examined REV-ERBβ-deficient mice and observed a similar increase in expression of genes involved in mitochondrial biogenesis and fatty acid β-oxidation. Consistent with these results, REV-ERBβ-deficient mice exhibited an altered metabolic phenotype compared to wild-type littermate controls when measured by indirect calorimetry. This likely compensated for the increased food consumption that occurred, possibly aiding in the maintenance of their weight over time. Since feeding behaviors are a direct circadian output, this study suggests that REV-ERBβ may have more subtle effects on circadian behaviors than originally identified. Furthermore, these data implicate REV-ERBβ in the control of skeletal muscle metabolism and energy expenditure and suggest that development of REV-ERBα versus REV-ERBβ selective ligands may have therapeutic utility in the treatment of metabolic syndrome.

Pharmacological Targeting the REV-ERBs in Sleep/Wake Regulation

The circadian clock maintains appropriate timing for a wide range of behaviors and physiological processes. Circadian behaviors such as sleep and wakefulness are intrinsically dependent on the precise oscillation of the endogenous molecular machinery that regulates the circadian clock. The identical core clock machinery regulates myriad endocrine and metabolic functions providing a link between sleep and metabolic health. The REV-ERBs (REV-ERBα and REV-ERBβ) are nuclear receptors that are key regulators of the molecular clock and have been successfully targeted using small molecule ligands. Recent studies in mice suggest that REV-ERB-specific synthetic agonists modulate metabolic activity as well as alter sleep architecture, inducing wakefulness during the light period. Therefore, these small molecules represent unique tools to extensively study REV-ERB regulation of sleep and wakefulness. In these studies, our aim was to further investigate the therapeutic potential of targeting the REV-ERBs for regulation of sleep by characterizing efficacy, and optimal dosing time of the REV-ERB agonist SR9009 using electroencephalographic (EEG) recordings. Applying different experimental paradigms in mice, our studies establish that SR9009 does not lose efficacy when administered more than once a day, nor does tolerance develop when administered once a day over a three-day dosing regimen. Moreover, through use of a time response paradigm, we determined that although there is an optimal time for administration of SR9009 in terms of maximal efficacy, there is a 12-hour window in which SR9009 elicited a response. Our studies indicate that the REV-ERBs are potential therapeutic targets for treating sleep problems as those encountered as a consequence of shift work or jet lag.

Correction: Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression

[This corrects the article DOI: 10.1371/journal.pone.0151014.].

Pharmacological and Genetic Modulation of REV-ERB Activity and Expression Affects Orexigenic Gene Expression

The nuclear receptors REV-ERBα and REV-ERBβ are transcription factors that play pivotal roles in the regulation of the circadian rhythm and various metabolic processes. The circadian rhythm is an endogenous mechanism, which generates entrainable biological changes that follow a 24-hour period. It regulates a number of physiological processes, including sleep/wakeful cycles and feeding behaviors. We recently demonstrated that REV-ERB-specific small molecules affect sleep and anxiety. The orexinergic system also plays a significant role in mammalian physiology and behavior, including the regulation of sleep and food intake. Importantly, orexin genes are expressed in a circadian manner. Given these overlaps in function and circadian expression, we wanted to determine whether the REV-ERBs might regulate orexin. We found that acute in vivo modulation of REV-ERB activity, with the REV-ERB-specific synthetic ligand SR9009, affects the circadian expression of orexinergic genes in mice. Long term dosing with SR9009 also suppresses orexinergic gene expression in mice. Finally, REV-ERBβ-deficient mice present with increased orexinergic transcripts. These data suggest that the REV-ERBs may be involved in the repression of orexinergic gene expression.

Eculizumab Salvage Therapy for Antibody-Mediated Rejection in a Desensitization-Resistant Intestinal Re-Transplant Patient

The presence of elevated calculated panel reactive antibody (cPRA) and anti-HLA donor specific antibodies (DSA) are high risk factors for acute antibody-mediated rejection (AAMR) in intestinal transplantation that may lead to graft loss. Eculizumab has been used for the treatment of AAMR in kidney transplantation of sensitized patients that do not respond to other treatment. Here, we report a case where eculizumab was used to treat AAMR in a desensitization-resistant intestinal re-transplant patient. A male patient lost his intestinal graft to AAMR 8.14 years after his primary transplant. He received a second intestinal graft that had to be explanted a month later due to refractory AAMR. The patient remained highly sensitized despite multiple treatments. He received a multivisceral graft and presented with severe AAMR on day 3 posttransplantation. The AAMR was successfully treated with eculizumab. The patient presently maintains an elevated cPRA level above 90% but his DSAs have decreased from 18 000 MFI (mean fluorescent intensity) to below the positive cut-off value of 3000 MFI and remains rejection free with a 2-year follow-up since his multivisceral transplant. Eculizumab offers an alternative to treat AAMR in intestinal transplantation in desensitization-resistant patients.

Pharmacological targeting of the mammalian clock regulates sleep architecture and emotional behaviour

Synthetic drug-like molecules that directly modulate the activity of key clock proteins offer the potential to directly modulate the endogenous circadian rhythm and treat diseases associated with clock dysfunction. Here we demonstrate that synthetic ligands targeting a key component of the mammalian clock, the nuclear receptors REV-ERBα and β, regulate sleep architecture and emotional behaviour in mice. REV-ERB agonists induce wakefulness and reduce REM and slow-wave sleep. Interestingly, REV-ERB agonists also reduce anxiety-like behaviour. These data are consistent with increased anxiety-like behaviour of REV-ERBβ-null mice, in which REV-ERB agonists have no effect. These results indicate that pharmacological targeting of REV-ERB may lead to the development of novel therapeutics to treat sleep disorders and anxiety.

Quantifying Drosophila food intake: comparative analysis of current methodology

Food intake is a fundamental parameter in animal studies. Despite the prevalent use of Drosophila in laboratory research, precise measurements of food intake remain challenging in this model organism. Here, we compare several common Drosophila feeding assays: the Capillary Feeder (CAFE), food-labeling with a radioactive tracer or a colorimetric dye, and observations of proboscis extension (PE). We show that the CAFE and radioisotope-labeling provide the most consistent results, have the highest sensitivity, and can resolve differences in feeding that dye-labeling and PE fail to distinguish. We conclude that performing the radiolabeling and CAFE assays in parallel is currently the best approach for quantifying Drosophila food intake. Understanding the strengths and limitations of food intake methodology will greatly advance Drosophila studies of nutrition, behavior, and disease.

MicroRNA signature of intestinal acute cellular rejection in formalin-fixed paraffin-embedded mucosal biopsies

Despite continuous improvement of immunosuppression, small bowel transplantation (SBT) is plagued by a high incidence of acute cellular rejection (ACR) that is frequently intractable. Therefore, there is a need to uncover novel insights that will lead to strategies to achieve better control of ACR. We hypothesized that particular miRNAs provide critical regulation of the intragraft immune response. The aim of our study was to identify miRNAs involved in intestinal ACR. We examined 26 small intestinal mucosal biopsies (AR/NR group; 15/11) obtained from recipients after SBT or multivisceral transplantation. We investigated the expression of 384 mature human miRNAs and 280 mRNAs associated with immune, inflammation and apoptosis processes. We identified differentially expressed 28 miRNAs and 58 mRNAs that characterized intestinal ACR. We found a strong positive correlation between the intragraft expression levels of three miRNAs (miR-142-3p, miR-886-3p and miR-132) and 17 mRNAs including CTLA4 and GZMB. We visualized these miRNAs within cells expressing CD3 and CD14 proteins in explanted intestinal allografts with severe ACR. Our data suggested that miRNAs have a critical role in the activation of infiltrating cells during intestinal ACR. These differences in miRNA expression patterns can be used to identify novel biomarkers and therapeutic targets for immunosuppressive agents.

Long-term results of biofeedback treatment for faecal incontinence: a comparative study with untreated controls

AIM

Long-term results of biofeedback for faecal incontinence are controversial. Moreover, its value compared with standard care has been recently questioned. The study aimed to analyse the long-term efficacy of biofeedback therapy for faecal incontinence to formed stool and to compare it with no treatment.

METHOD

Seventy-nine patients with faecal incontinence to solid stool were evaluated at baseline and 1, 6, 36 and 60 months after treatment. To compare the long-term results with no treatment, 40 patients initially evaluated but not referred for therapy were used as controls.

RESULTS

More than 80% of patients recovered continence or had a reduction in the number of episodes of incontinence greater than 75% at 1, 6, 36 and 60 months, indicating that the success rate of biofeedback was maintained over time. At 60 months, 86% of patients treated with biofeedback were fully continent or had a > 75% reduction in the number of incontinent episodes compared to 26% of the untreated patients (P < 0.001).

CONCLUSION

Biofeedback therapy is effective in patients with faecal incontinence to formed stool compared with no treatment. Overall, clinical improvement is maintained in the long term.

Dynamical origin of spectrally rich vocalizations in birdsong

Birdsong is a model system for learned vocal behavior with remarkable parallels to human vocal development and sound production mechanisms. Upper vocal tract filtering plays an important role in human speech, and its importance has recently also been recognized in birdsong. However, the mechanisms of how the avian sound source might contribute to spectral richness are largely unknown. Here we show in the most widely studied songbird, the zebra finch (Taeniopygia guttata), that the broad range of upper harmonic content in different low-frequency song elements is the fingerprint of the dynamics displayed by its vocal apparatus, which can be captured by a two-dimensional dynamical model. As in human speech and singing, the varying harmonic content of birdsong is not only the result of vocal tract filtering but of a varying degree of tonality emerging from the sound source. The spectral content carries a strong signature of the intrinsic dynamics of the sound source.

Dialysis outcomes in Colombia (DOC) study: a comparison of patient survival on peritoneal dialysis vs hemodialysis in Colombia

The goal of the Dialysis Outcomes in Colombia (DOC) study was to compare the survival of patients on hemodialysis (HD) vs peritoneal dialysis (PD) in a network of renal units in Colombia. The DOC study examined a historical cohort of incident patients starting dialysis therapy between 1 January 2001 and 1 December 2003 and followed until 1 December 2005, measuring demographic, socioeconomic, and clinical variables. Only patients older than 18 years were included. As-treated and intention-to-treat statistical analyses were performed using the Kaplan-Meier method and Cox proportional hazard model. There were 1094 eligible patients in total and 923 were actually enrolled: 47.3% started HD therapy and 52.7% started PD therapy. Of the patients studied, 751 (81.3%) remained in their initial therapy until the end of the follow-up period, death, or censorship. Age, sex, weight, height, body mass index, creatinine, calcium, and Subjective Global Assessment (SGA) variables did not show statistically significant differences between the two treatment groups. Diabetes, socioeconomic level, educational level, phosphorus, Charlson Co-morbidity Index, and cardiovascular history did show a difference, and were less favorable for patients on PD. Residual renal function was greater for PD patients. Also, there were differences in the median survival time between groups: 27.2 months for PD vs 23.1 months for HD (P=0.001) by the intention-to-treat approach; and 24.5 months for PD vs 16.7 months for HD (P<0.001) by the as-treated approach. When performing univariate Cox analyses using the intention-to-treat approach, associations were with age > or =65 years (hazard ratio (HR)=2.21; confidence interval (CI) 95% (1.77-2.755); P<0.001); history of cardiovascular disease (HR=1.96; CI 95% (1.58-2.90); P<0.001); diabetes (HR=2.34; CI 95% (1.88-2.90); P<0.001); and SGA (mild or moderate-severe malnutrition) (HR=1.47; CI 95% (1.17-1.79); P=0.001); but no association was found with gender (HR=1.03, CI 95% 0.83-1.27; P=0.786). Similar results were found with the as-treated approach, with additional associations found with Charlson Index (0-2) (HR=0.29; Cl 95% (0.22-0.38); P<0.001); Charlson Index (3-4) (HR=0.61; Cl 95% (0.48-0.79); P<0.001); and SGA (mild-severe malnutrition) (HR=1.43; Cl 95% (1.15-1.77); P<0.001). Similarly, the multivariate Cox model was run with the variables that had shown association in previous analyses, and it was found that the variables explaining the survival of patients with end-stage renal disease in our study were age, SGA, Charlson Comorbidity Index 5 and above, diabetes, healthcare regimes I and II, and socioeconomic level 2. The results of Cox proportional risk model in both the as-treated and intention-to-treat analyses showed that there were no statistically significant differences in survival of PD and HD patients: intention-to-treat HD/PD (HR 1.127; CI 95%: 0.855-1.484) and as-treated HD/PD (HR 1.231; CI 95%: 0.976-1.553). In this historical cohort of incident patients, there was a trend, although not statistically significant, for a higher (12.7%) adjusted mortality risk associated with HD when compared to PD, even though the PD patients were poorer, were more likely to be diabetic, and had higher co-morbidity scores than the HD patients. The variables that most influenced survival were age, diabetes, comorbidity, healthcare regime, socioeconomic level, nutrition, and education.

Ischemic pre-conditioning in deceased donor liver transplantation: a prospective randomized clinical trial

To assess the immediate and long-term effects of ischemic preconditioning (IPC) in deceased donor. liver transplantation (LT), we designed a prospective, randomized controlled trial involving 60 donors: control group (CTL, n = 30) or study group (IPC, n = 30). IPC was induced by 10-min hiliar clamping immediately before recovery of organs. Clinical data and blood and liver samples were obtained in the donor and in the recipient for measurements. IPC significantly improved biochemical markers of liver cell function such as uric acid, hyaluronic acid and Hypoxia-Induced Factor-1 alpha (HIF-1 alpha) levels. Moreover, the degree of apoptosis was significantly lower in the IPC group. On clinical basis, IPC significantly improved the serum aspartate aminotransferase (AST) levels and reduced the need for reoperation in the postoperative period. Moreover, the incidence of primary nonfunction (PNF) was lower in the IPC group, but did not achieve statistical significance. We conclude that 10-min IPC protects against I/R injury in deceased donor LT.

Clinical trial on the cost-effectiveness of T-tube use in an established deceased donor liver transplantation program

The aim of our study was to assess the advantages and disadvantages of T-tube use in liver transplantation, with also paying attention to the economic costs derived from its use. Patients were prospectively randomized to T tube or no T tube. One hundred and seven patients, 53 with T tube and 54 without T tube, were analyzed. Minimum follow-up was three months. Nine patients (8.4%) had bile leak: six in the T-tube group (11.3%) and three in the group without T tube (5.5%), p = ns. Four patients (3.5%) had anastomotic biliary stenosis: one in the T-tube group (1.8%) and three in the group without T tube, p = ns. Twenty of the 53 patients (37.7%) with T tube had T-tube-related complication. The number of diagnostic and therapeutic resources were higher in the T-tube group compared with non-T tube (81 and 17 vs. 18 and 10, respectively, p <0.05). The costs of therapeutic procedures required for the treatment of complications were 28 232 euro in the T-tube group vs. 16 088 euro in the no T-tube group, p <0.05. In conclusion, the systematic use of the T tube in biliary reconstruction in liver transplantation cannot be justified.

Dynamical systems techniques reveal the sexual dimorphic nature of motor patterns in birdsong

In this work we analyze the pressure motor patterns used by canaries (Serinus canaria) during song, both in the cases of males and testosterone treated females. We found a qualitative difference between them which was not obvious from the acoustical features of the uttered songs. We also show the diversity of patterns, both for males and females, to be consistent with a recently proposed model for the dynamics of the oscine respiratory system. The model not only allows us to reproduce qualitative features of the different pressure patterns, but also to account for all the diversity of pressure patterns found in females.

Nm 283, an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine

In order to improve the oral bioavailability of 2-C-methylcytidine, a potent anti-HCV agent, the corresponding 3'-O-L-valinyl ester derivative (NM 283) has been synthesized Based on its ease of synthesis and its physicochemical properties, NM 283 has emerged as a promising antiviral drug for treatment of chronic HCV infection.

One Thousand Liver Transplants: The Hospital Clinic Experience

OBJECTIVES

Our goal was to study a consecutive series of 1000 liver transplants performed in our institution to evaluate the changes over time in donors, recipients, and results.

PATIENTS AND METHODS

With the aim to evaluate differences between transplantation in the first period and the present period, the first consecutive 100 liver transplants performed from June 1988 to June 1990 (first period) were compared with the last consecutive 200 liver transplants performed from January 2001 to June 2003 (second period).

RESULTS

Increased donor age, change in donor cerebral death etiology, and increasing numbers of grafts from alternative methods using cadaveric donors were observed in the second period. Piggy-back technique and the biliary anastomosis without a t-tube was also started in the second period. One-year actuarial patient survival was higher in the second period (84% vs 91.3%). The need for retransplantation in the overall series was 95%. One-, 5-, and 10-year actuarial retransplant survival was 67.7%, 51.3%, and 39.4%, respectively.

CONCLUSIONS

Technical innovations, better understanding of donor and recipient aspects, and global improvements were the reasons for time-related improved results of liver transplantation.

Cost/efficacy clinical trial about the use of T-tube in cadaveric donor liver transplant: preliminary results

Biliary reconstruction is the most common cause of morbidity associated with orthotopic liver transplantation. Our objective was to assess the complications and hospital resources related to the use of a T-tube.

MATERIAL AND METHODS

Among 95 liver transplants performed from October 2002 to November 2003, 84 patients were randomized to receive a T-tube or no T-tube. We analyzed all patients with a follow-up of at least of 3 months.

RESULTS

Fifty-five transplants were analyzed with 8 months mean follow-up, including twenty eight with T-tube and twenty seven without a T-tube. No patient died during the follow-up. The overall rate of biliary complications was 45.4% (25/55) including 21/28 (75%) in the T-tube group and 4/27(14.8%) in the non-T-tube group (P < .0001). Complications related to T-tube extraction occurred in 48.2% (13/27), including 3 cholangitis and 10 leaks. The costs of hospital resources due to radiological studies were 5329 capital JE, Ukrainian for the T-tube group vs 5785 capital JE, Ukrainian for the non-T-tube group. The costs of hospital resources due to treatment were 28,280 capital JE, Ukrainian for the T-tube group vs 10,088 capital JE, Ukrainian for the non-T-tube group.

CONCLUSIONS

Use of a T-tube during orthotopic liver transplantation does not seem justified. Biliary anastomosis stenting is followed by an increased incidence of complications, most of which are related to its use. Hospital stay, radiological studies, and cost of hospital resources are higher among the T-tube patients. Therefore its systematic use is not advisable.

Evolutionary change in the structure of the regulatory region that drives tissue and temporally regulated expression of alcohol dehydrogenase gene in Drosophila funebris

The Adh locus of Drosophilidae is organized as a single gene transcribed from two spatially and temporally regulated promoters except in species of the repleta group, which have two single promoter genes. Here we show that in Drosophila funebris the Adh gene is transcribed from a single promoter, in both larva and adult, with qualitative and quantitative species specific-differences in tissue distribution. The gene is expressed in larval fat body but in other tissues such as gastric caeca, midgut and Malpighian tubules its expression is reduced compared to most Drosophilidae species, and in adults it is almost limited to the fat body. The comparative analysis of gene expression of two strains, which differ by a duplication, indicates that the cis elements necessary for this pattern of expression in larvae are included in the region of 1.55 kb upstream of the transcription initiation site. This new organization reveals the evolution of a different regulatory strategy to express the Adh gene in the subgenus Drosophila.

Binding and activation of human plasminogen by Mycobacterium tuberculosis

The first evidence of the interaction of Mycobacterium tuberculosis with the plasminogen system is herein reported. By FACScan analysis and affinity blotting, lysine-dependent binding of plasminogen to M. tuberculosis was demonstrated. The binding molecules were 30-, 60-, and 66-kDa proteins present in cell wall and soluble protein extracts. The activation of plasminogen, which occurred only in presence of fibrin and was not inhibited by the host serpin, alpha(2)-antiplasmin, was also demonstrated.

Nonfixed duplication containing the Adh gene and a truncated form of the Adhr gene in the Drosophila funebris species group: different modes of evolution of Adh relative to Adhr in Drosophila

The sequence of the genomic region that contains the Adh and Adhr genes of Drosophila funebris was used to demonstrate that both genes are present in species of the funebris group. The sequence of this genomic region reveals a 2.9-kb tandem duplication which encompasses 1.6 kb of the 5' flanking region, the entire Adh gene, and two thirds of the first exon of the Adhr gene in D. funebris. This duplication is not fixed in this species since some strains do not carry the duplication. The Adh duplication has also been found in another species of the funebris group, Drosophila macrospina macrospina. The sequence analysis of the 5'-flanking region of the Adh gene indicates a single promoter and shows stretches of high similarity with cis-acting elements responsible for the expression of Adh in Drosophila melanogaster. In confirmation of this indication, the larval and adult transcripts have the same length, which corresponds to the transcription from the promoter proximal to the coding region. The codon bias of the Adh gene of D. funebris is among the lowest reported for any Adh gene in the Drosophilidae species and is very similar to that of the Adhr gene. The Adhr gene evolves slightly faster than Adh at synonymous positions. At nonsynonymous positions, the Adh gene evolves 2.5 times faster than Adhr in the species pair D. funebris-Drosophila immigrans, while in other interspecific comparisons the average is about 1.25. However, in comparisons between some species within the melanogaster and obscura groups, Adh evolves at half the rate of Adhr. The phylogenetic trees constructed with the coding region of the Adh gene cluster D. funebris and D. immigrans and clearly separate them from the clade in which virilis, repleta, and Hawaiian species are grouped. Using the evolutionary synonymous rate estimated for Hawaiian species, the divergence time of D. funebris from the virilis-repleta-Hawaiian clade was estimated as 34.3 Myr, and the divergence time of D. funebris and D. immigrans was estimated as 23.5 Myr.

CD26 expression and dipeptidyl peptidase IV activity in an aggressive hepatosplenic T-cell lymphoma

The transmembrane serine aminopeptidase dipeptidyl peptidase IV (DPP IV) (also known as CD26) participates in several immunological functions and has a binding affinity for several molecules, including collagen, which may be an integral mechanism for T cells to traverse endothelial barriers. Since CD26 is phenotypically expressed in certain T-cell malignancies, this study utilized a novel four-color cytofluorographic procedure to measure DPP IV enzymatic activity concurrently with the expression of other surface markers in an aggressive hepatosplenic T-cell lymphoma. Immunophenotypic analysis by flow cytometry revealed the tumor to be CD2+, CD3+, CD5-, CD7+, TcR-gamma/delta+, CD4-, CD8+/-, CD56+, and CD11c+. The CD26 molecule was also expressed, and DPP IV activity was present, with the maximal activity detectable after 10 min of incubation. These results represent the initial description of enzymatically active CD26 in a T-cell malignancy, and raise the possibility that this molecule may be a participant in the pathogenetic mechanisms utilized by the neoplastic cells.

Immunological markers of disease progression in patients infected with the human immunodeficiency virus

Identification of inexpensive and technically simple immunological tests useful in predicting the progression to AIDS in human immunodeficiency virus (HIV)-infected patients would be especially welcome in developing countries, in which 80% of HIV-infected patients reside and health budgets are low. In the current study, we evaluated CD4+ and total lymphocyte counts and the concentrations in serum of beta 2-microglobulin, p24 antigen, and immunoglobulin A (IgA) as predictors of disease progression in 74 Panamanian HIV-positive patients and 50 HIV-negative healthy individuals. Total lymphocyte and CD4(+)-cell counts for AIDS patients (1,451 +/- 811 cells/microliters, P < 0.001, and 238 +/- 392 cells/microliters, P < 0.0001, respectively and asymptomatic patients (2,393 +/- 664 cells/microliters, P > 0.05, and 784 +/- 475 cells/microliters, P < 0.001, respectively) were lower than those observed for healthy subjects (2,596 +/- 631 cells/microliters and 1,120 +/- 296 cells/microliters, respectively). The levels of beta 2-microglobulin and IgA in serum were significantly elevated in patients with AIDS (5.7 +/- 3.6mg/liter, P < 0.001, and 541 +/- 265 mg/dl, P < 0.0002, respectively) and asymptomatic infected subjects (3.4 +/- 2.1 mg/liter, P = 0.001, and 436 +/- 216 mg/dl, P < 0.0001, respectively) compared with the levels in healthy subjects (2.2 +/- 0.7 mg/liter and 204 +/- 113 mg/dl, respectively). Nonstatistically significant differences (P > 0.05) for concentrations of p24 antigen between asymptomatic infected patients (29 +/- 13 pg/ml) and AIDS patients (40 +/- 23 pg/ml) were observed. Total lymphocyte counts of 1,750 cells/microliters or less, CD4 counts of 200 cells/microliters or less, beta 2-microglobulin concentrations in serum of 4 mg/liter or higher, concentrations of IgA in serum of 450 mg/dl or higher, and the presence in serum of p24 antigen were correlated with elevated risks for developing AIDS. Monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring the immune status of HIV-positive patients.

Postthaw viability of frozen human ovarian cancer tumor specimens

Thirty-five human ovarian cancer tumor specimens were frozen by both rapid freeze and slow freeze with dimethyl sulfoxide (DMSO) to determine which method results in optimal postthaw viability. Median viability following a rapid freeze was 8% as compared to 90% with slow freeze with DMSO (P = .0001). Eighty-seven percent of tumors had a viability of > 80% following slow freeze with DMSO. When experimentation on human ovarian cancer tumor cells requires postthaw viability, we recommend slow freeze with DMSO.

Structural changes in rat Leydig cells posthypophysectomy: a morphometric and endocrine study

Short and long term responses of the rat Leydig cell were studied posthypophysectomy, at times when germ cell degeneration was first prominent (6 days) and after long term regression of the testis (28 days). In the short term, virtually all structural parameters relating to the volume and surface area of the Leydig cell and its subcellular organelles were significantly lowered compared with those in control animals. Exceptions were the volumes of the nucleolus, heterochromatin, and lysosomes and the surface areas of the nucleus. Structural decreases were generally on the order of 2- to 5-fold in the 6-day period. A statistical analysis of the percent decreases in the short term was performed to determine whether any particular structural features were more sensitive to hypophysectomy than any others. In most instances, no particular organelles were decreased compared to others. However, lipid, although not commonly seen in rat Leydig cells, showed significantly greater percent decreases compared with several other organelles, indicating that the small amount of lipid present is rapidly lost (used) in the short term. After long term hypophysectomy, all structural parameters of the Leydig cell were significantly lowered compared with those in pituitary-intact animals. Only a few parameters (mitochondrial volume, cell surface area, and the surface areas of inner and outer mitochondrial membranes and smooth endoplasmic reticulum) showed more significant decreases in the long term compared with the short term hypophysectomized animals. Most organelle volumes and surface areas correlated positively and significantly with serum and tissue testosterone levels; the exceptions were the volumes of the nucleolus, heterochromatin, lipid, and lysosomes. Compared with the pituitary-intact animal, the content of LH receptors expressed per testis and per Leydig cell was significantly lower in both hypophysectomized groups; however, the number of receptors per given area of individual Leydig cell plasma membrane remained unchanged. Overall, data show that the Leydig cell manifests marked structural changes during early spermatogenic dysfunction.

Streptozotocin-induced deficits in sex behavior and neuroendocrine function in male rats

The effects of streptozotocin-induced (STZ) diabetes on neuroendocrine and sexual function were evaluated in adult male rats. Adult male rats were injected with STZ (50 mg/kg) or vehicle and tested for copulatory behavior 7, 14, and 21 days later. The rats were killed 1 month after STZ or vehicle treatment for measurement of plasma hormone levels, hypothalamic catecholamine turnover, LHRH content, and in vitro pituitary function. The STZ rats showed significant deficits in mount, intromission, and ejaculatory behaviors. Plasma levels of testosterone, LH, FSH, and PRL were all significantly reduced in the STZ compared to the control rats, but in vitro LH secretion was enhanced after STZ treatment. In vitro PRL secretion and the inhibitory response to dopamine did not differ between the two groups. The levels of LHRH were reduced in the medial basal hypothalamus (MBH), but LHRH levels in the median eminence (ME) and anterior hypothalamus (AH) were unchanged after STZ treatment. Norepinephrine turnover was reduced in the ME, MBH, and AH of the STZ rats, while dopamine turnover was unchanged in the ME, increased in the MBH, and reduced in the AH of the STZ rats compared to those in the vehicle-treated controls. These results suggest that changes in pituitary and testicular function in rats made diabetic by STZ treatment are secondary to changes in hypothalamic catecholamine metabolism. Changes in copulatory behavior could be due to both reductions in plasma testosterone levels as well as changes in central neurotransmitter metabolism.

Insulin-like growth factor I levels in proportionate dogs, chondrodystrophic dogs and in giant dogs

Plasma insulin-like growth factor I concentrations from proportionate, chondrodystrophic and giant breeds were evaluated and compared with body size. IGF-I plasma concentrations were 91.2 +/- 10.9 micrograms/l in Keeshounds (proportionate dog), 122.6 +/- 25.4 micrograms/l in Bassethounds (chondrodystrophic dog) and 280 +/- 22.8 micrograms/l in German Shepherds (proportionate dog). The highest IGF-I level (389.6 +/- 24.2 micrograms/l) was found in the New Foundland, a giant breed (mean +/- SEM). The mean body weight was 11.8 +/- 0.4 kg in Keeshounds, 15.4 +/- 1.4 kg in Bassethounds, 32 +/- 1.5 kg in German Shepherds, and 45.6 +/- 1.7 kg in New Foundlands (mean +/- SEM). Body weight and plasma IGF-I concentration were significantly correlated (y (IGF-I) = -7.43 + 8.7 X (body weight); P less than 0.0001.

Malignant angioendotheliomatosis--a true lymphoma: a case of intravascular malignant lymphomatosis studied by southern blot hybridization analysis

Malignant angioendotheliomatosis is a rare, systemic, usually fatal disease characterized by a massive proliferation of large, bizarre-looking mononuclear cells within small and medium-sized blood vessels. The histogenesis of the neoplastic cells has been the subject of long-standing controversy since the disease's initial description. Early investigators concluded that the entity represented a neoplasm of endothelial cells, but recently others have suggested that it is of lymphoid origin. We studied a case of malignant angioendotheliomatosis by Southern blot hybridization analysis which showed clonal rearrangements of the immunoglobulin heavy-chain gene strongly suggesting a B-lymphocyte origin. Our results provide additional evidence that malignant angioendotheliomatosis is an intravascular malignant lymphomatosis.

Effects of photoperiod, hypophysectomy, and follicle-stimulating hormone on testicular follicle-stimulating hormone binding sites in golden hamsters

Experiments were conducted to partially characterize and to examine the regulation of unoccupied testicular follicle-stimulating hormone (FSH) binding sites in adult golden hamsters. Testicular FSH binding sites were measured in the 1800 X gav fraction of whole testicular homogenates using iodinated bovine FSH. Binding of FSH was highly specific for FSH, located primarily in the testes, was time- and temperature-dependent, initially reversible, saturable, and consistent with a model consisting of a single class of high-affinity binding sites (range of equilibrium association constants (Ka) 2-12 X 10(10) M-1). Exposure of hamsters to a short photoperiod consisting of 5L:19D was associated with an increase in concentration (fmol/mg protein), but a reduction in total content (fmol/testes) of testicular FSH binding sites. There was no appreciable 5L:19D-associated alteration in receptor affinity (average Ka = 7.83 X 10(10) M-1). Injections of ovine prolactin (oPRL), ovine luteinizing hormone (oLH), or ovine FSH (oFSH) for 3 days into hamsters housed in 5L:19D for 12 wk had no effect on photoperiod-induced changes in testicular FSH binding sites. On Days 5 and 6 post hypophysectomy, a dramatic increase in FSH binding site concentration occurred, with but marginal effects on binding site affinity. Injections of 5 micrograms oFSH on Days 2, 3, and 4 after hypophysectomy prevented the increase in binding site concentrations measured on Day 5. Injection of a combination of 5 micrograms oFSH, 50 micrograms oPRL, and 25 micrograms oLH also reduced testicular FSH binding site concentrations in hypophysectomized hamsters, but oPRL or oLH by themselves were ineffective. The data indicate a homologous down-regulation of testicular FSH binding sites, but do not exclude the involvement of other hormones.

Prevalence and age at development of enamel hypoplasias in Mexican children

Enamel hypoplasias, deficiencies in enamel thickness resulting from disturbances during the secretory phase of enamel development, are generally believed to result from nonspecific metabolic and nutritional disruptions. However, data are scare on the prevalence and chronological distributions. of hypoplasias in populations experiencing mild to moderate malnutrition. The purpose of this article is to present baseline data on the prevalences and chronological distributions of enamel hypoplasias, by sex and for all deciduous and permanent anterior teeth, in 300 5 to 15-year-old rural Mexican children. Identification of hypoplasias was aided by comparison to a published standard (Federation Dentaire Internationale: Int. Dent. J. 32(2):159-167, 1982). The location of defects, by transverse sixths of tooth crowns, was used to construct distributions of defects by age at development. One or more hypoplasias were detected in 46.7% (95% CI = 40.9-52.5%) of children. Among the unworn and completely erupted teeth, the highest prevalence of defects was found on the permanent maxillary central incisors (44.4% with one or more hypoplasias), followed by the permanent maxillary canine (28.0%) and the remaining permanent teeth (26.2 to 22.2%) Only 6.1% of the completely erupted and unworn deciduous teeth were hypoplastic. The prevalence of enamel defects on the permanent teeth was up to tenfold greater than that found in studies of less marginal populations that used the FDI method. The prevalence of defects in transverse zones suggests a peak frequency of hypoplasias during the second and third years for the permanent teeth, corresponding to the age at weaning in this group. In the deciduous teeth, a smaller peak occurs between 30 and 40 weeks post gestation. The frequency of defects after three years of age is slightly higher in females than males, suggesting a sex difference in access to critical resources.

Regulation of testicular LH/hCG receptors in golden hamsters (Mesocricetus auratus) during development

During prepubertal development in the golden hamster, there are major age-related changes in the number of testicular LH/hCG receptors. Between 22 and 35 days of age, there was greater than 10-fold increase in testicular LH/hCG receptors, followed by a decrease at Day 37. Concomitant with, but preceding slightly, the changes in receptors, were increases in plasma LH and FSH and most noticeably prolactin concentrations, between Days 10 and 20 of age. Inhibition of the increases in plasma levels of prolactin by daily injections of bromocriptine, between 14 and 31 days of age, resulted in suppressed testicular and seminal vesicle weights, and decreased content and concentration of testicular LH/hCG receptors. Similarly, the premature increase in plasma prolactin concentrations in prepubertal hamsters between 6 and 20 days of age, by means of ectopic pituitary transplants, resulted in increased testicular and seminal vesicle weights, as well as an increase in the concentration of testicular LH/hCG receptors. These results strongly suggest that increases in plasma prolactin values during development are important in enhancement of the development of testicular LH/hCG receptors.

Effects of photoperiod and hCG on the regulation of testicular LH/hCG receptors in Syrian hamsters (Mesocricetus auratus)

The regulation of testicular LH/hCG receptors was studied in Syrian (golden) hamsters with testicular atrophy induced by exposure to short photoperiod (5L:19D) and in gonadally active hamsters kept in a long photoperiod (14L:10D). By 24 h after injection of hCG, long-photoperiod hamsters showed a dose-related decrease in the number of testicular LH/hCG receptors. At 48 and 72 h, there was a recovery from this 'down-regulation'. The recovery was much faster than has been reported for the rat and mouse, and it resulted in elevation of testicular LH/hCG receptor concentrations above basal values. Hamsters with short photoperiod-induced testicular atrophy showed an increase in testicular LH/hCG receptors after injection of hCG, except for animals injected with a very high dose. The hCG-induced increase in testicular LH/hCG binding in these animals was associated with reappearance of testosterone responses to subsequent hCG stimulation. Response of testicular LH/hCG receptors to hCG in prepubertal hamsters resembled that measured in animals with short photoperiod-induced gonadal atrophy.

Effects of different numbers of ectopic pituitary transplants on regulation of testicular LH/hCG and prolactin receptors in the hamster (Mesocricetus auratus)

Adult male hamsters were given transplants of 1/2, 1, 2, 3 or 4 pituitaries under the kidney capsule and were killed 4 weeks later. Pituitary transplants produced a significant, dose-related increase in plasma prolactin levels, no changes in plasma LH and an increase in plasma FSH. Concentration of LH/hCG receptors in the testes was significantly increased in animals with 2 or 3 transplants and concentration of testicular prolactin receptors was significantly increased in those given 2 transplants. The apparent stimulatory effects of 1/2, 1 or 4 transplants on testicular LH/hCG and prolactin binding were not statistically significant. Some of the animals were injected with 0.3 i.u. hCG/g body weight 24 h before being killed. This produced a significant reduction in the levels of prolactin receptors and an apparent reduction in the levels of LH/hCG receptors in the testes. Elevation of plasma testosterone concentrations in response to hCG was significantly greater in animals given 3 or 4 pituitary transplants than in the remaining groups. These results provide further evidence that prolactin increases the number of LH/hCG and prolactin receptors in the hamster testis and suggest that changing the number of ectopic pituitary transplants may result in biphasic effects on the testis, with 2 or 3 transplants being maximally stimulatory.

Testicular LH receptors during aging in Fisher 344 rats

Levels of serum LH, prolactin, testosterone, progesterone and 17-OH progesterone and the testicular concentration and total content of LH receptors were measured in 4-, 11-, 18-, and 27-month-old Fisher 344 rats. All 27-month-old rats had Leydig cell tumors. At first, testicular LH receptor levels decreased with age, but with the appearance of the testicular tumors, these levels increased dramatically. Serum prolactin levels fluctuated with age, but were significantly decreased in 27-month-old rats, as were serum LH levels. Serum testosterone levels decreased steadily with age, while the testosterone-LH receptor ratio remained constant until the appearance of the testicular tumors, after which the ratio decreased precipitously. Serum progesterone levels remained constant throughout the life of Fisher 344 rats until the appearance of testicular tumors, when they increased dramatically. Serum 17-OH progesterone levels were increased significantly at 11 and 27 months as compared to four months of age, but levels at 18 months were similar to those seen in the 4-month-old animals. Therefore, in aged Fisher 344 rats with spontaneous Leydig cell tumors, there is an alteration in the testicular testosterone synthesizing pathway at a step after progesterone.

Autoregulation of testicular luteinizing hormone receptors in hypogonadal (hpg/hpg) mice

The autoregulation of testicular luteinizing hormone (LH) receptors was studied in hypogonadal (hpg/hpg) and normal mice. The basal concentration of LH receptors was more than three-fold higher in hpg/hpg than in normal mice. After injection of hCG, hpg/hpg mice showed a decrease in LH receptor levels which was not observed in normal mice. Plasma testosterone was undetectable in hpg/hpg mice, even after treatment with a single dose of hCG. Plasma prolactin levels were higher in hpg/hpg than in normal mice. The increase in basal LH receptor levels is thought to be due to a compensatory mechanism in which elevated prolactin could play a role. The differences between hpg/hpg and normal mice in the autoregulation of LH receptors observed could be due to the "hypersensitivity" of the physiologically immature testis in hpg/hpg mice to the action of hCG, to gonadotropin deficiency, particularly during the earlier stages of development, or to a direct effect of the hpg locus on the metabolism of LH receptors.

Altered hypothalamic monoamine metabolism and pituitary prolactin regulation in female spontaneously hypertensive rats

Prolactin (PRL) secretion after aromatic amino acid decarboxylase inhibition with NSD-1015 was significantly elevated in female spontaneously hypertensive rats (SHR) as compared to normotensive (WKY) controls. Although basal PRL levels tended to be elevated in SHR rats, the differences were not significant. In vitro PRL secretion was also significantly elevated in the SHR rats as compared to the WKY rats, but the SHR rats were more responsive to the inhibitory effects of dopamine (DA). Despite changes in pituitary PRL secretion and DA response, there was no apparent difference in tubero-infundibular DA activity between the two rat strains. Hypothalamic serotonin levels were elevated in SHR rats, but metabolism did not appear to be significantly changed based on measurements of 5-hydroxytryptophan accumulation after NSD-1015 treatment.

Effects of alleles at the W locus on testicular luteinizing hormone receptors in adult mice

The autoregulation of testicular LH receptors was studied in Wx/Wv mice with germ cell aplasia and in normal (+/+) mice. To assess the effects of each individual allele, Wx/+ and Wv/+ mice were also examined. Basal testicular LH receptor concentration was higher in Wx/Wv mice than in all other genotypes, and higher in Wx/+ than in +/+ mice. Twenty-four h after injection of 0.3 IU hCG/g bw, LH receptor concentration was decreased in +/+ and Wv/+ mice, but not in Wx/Wv or Wx/+ animals. Administration of hCG caused a significant increase in plasma testosterone levels in all genotypes. However, injection of the highest dose of hCG used (0.9 IU/g bw) caused a significantly greater elevation in plasma testosterone in Wx/Wv than in +/+ mice. Plasma gonadotropin levels were significantly higher in Wx/Wv mice than in all other genotypes. The present results indicate that the Wx allele is responsible for the changes in testicular function observed in Wx/Wv mice, and suggest that this allele may be involved in the genetic regulation of testicular LH receptors in the mouse.

Relationship of the length of exposure to short photoperiod to the effect of prolactin on pituitary and testicular function in the golden hamster

Adult male golden hamsters were given ectopic pituitary transplants at the time of transfer from a long (stimulatory) photoperiod (14 h L:10 h D) to a short photoperiod (5L:19D) or at various intervals thereafter. Grafts given at the time of transfer to 5L:19D failed to maintain plasma FSH levels significantly above those observed in sham-operated controls or to prevent regression of the testes. Grafts given after 4 weeks in 5L:19D increased plasma FSH levels and significantly diminished the decrease in testicular volume. Grafts given 14 weeks after transfer to 5L:19D caused a modest increase in plasma FSH levels and did not significantly alter the time course of testicular redevelopment. Similarly, grafts given 18 weeks after transfer to 5L:19D had no effect on testicular weight measured 2.5 weeks later. These results indicate that the ability of prolactin (secreted by the grafted pituitary) to increase testicular size and the responsiveness of the hypothalamic-pituitary system to prolactin gradually increase during short photoperiod-induced testicular regression, are maximal when the testes are fully regressed and decrease again during spontaneous redevelopment of the testes. We suggest that the effects of prolactin on the testes in golden hamsters are partly mediated by prolactin-induced stimulation of FSH release from the in-situ pituitary.

Teaching andrology in U.S. and Canadian medical schools: a questionnaire

Based on the questionnaires answered by 60 of the 140 schools surveyed, it is apparent that the teaching of andrology receives little emphasis in the schools' curricula. The lack of support given to the teaching of andrology is more evident at the postgraduate than at the undergraduate level. Although andrology is relatively new as an independent biochemical specialty, it is suggested that increased availability of information on andrology to students and physicians would have a positive impact on the quality of health care.