Post-partum Fever of Unknown Origin: An Inaugural Flare of Severe Lupus With Multisystemic Involvement and Hemophagocytic Syndrome

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect almost every organ. Lupus protein-losing enteropathy (PLE) is one of the rarest manifestations of gastrointestinal involvement. Lupus flare as initial presentation is rare and the disease can act as a trigger to other pathologic immune syndromes like Hemophagocytic Lymphohistiocytosis (HLH), although this association is rare. We report the case of a previously healthy African 39-year-old female patient, with a recent history of cesarean section. Admitted to the Emergency Department (ED) with diffuse abdominal pain and fever, having completed a cycle of antibiotic therapy for initially suspected endometritis. The clinical picture progressed with sustained high fever, new-onset lymphadenopathies, systemic rash, acute pulmonary edema and seizures. Laboratory findings included hyperferritinemia, hypertriglyceridemia, proteinuria and hypoalbuminemia. The auto-immune panel was positive for antinuclear antibodies (ANA), anti-dsDNA, anti-SSA and anti-SSB, anti-PL7, anti-RNP, anti-U1-SnRNP, and anti-Pm-Scl75. She also presented hypocomplementemia. An inaugural flare of SLE with multisystemic involvement and concomitant secondary Hemophagocytic Syndrome was considered and therapy with methylprednisolone pulses, Anakinra and Cyclophosphamide was started. By the end of the first cycle of cyclophosphamide, the patient presented clinical worsening with abdominal pain recrudescence and profuse diarrhea. After the exclusion of an infectious process, a Lupus PLE was assumed and Cyclophosphamide protocol was resumed, with sustained clinical improvement after the induction protocol. Despite initially suspected gynecological infection, the clinical progression with multisystemic involvement together with the auto-immune panel made the diagnosis of SLE possible, with other laboratory findings raising the suspicion of HLH. This case represents a rare report of severe SLE with multiple organ involvement accompanied by HLH. Gastrointestinal involvement with PLE added rarity and morbidity to the clinical picture. The case reinforces the idea that when organ dysfunction is due to a severe autoimmune response, supportive treatment can be lifesaving until immunosuppressive drugs reach their full effect.

The influence of overweight and obesity in the oral health of a sample of portuguese adults

Background

Overweight and obesity may lead to different problems in various body systems and in the oral cavity. Dental caries and periodontal disease have been related with overweight. The aim of this study was to assess how overweight and obesity have impact on the lifestyle, oral habits and oral pathologies.

Methods

We conducted an observational cross-sectional study where we applied a questionnaire to 140 individuals from Lisbon and Viseu, Portugal., which 70 had a normal Body Mass Index (BMI) (control group) and 70 had an excessive BMI. We also made an oral observation in each individual to record the permanent teeth decayed, missing and filled index (DMFT), the Community Periodontal Index and the oral hygiene status.

Results

From the final sample, 30% of the subjects with overweight brushed their teeth once a day or less, while the majority (62.9%) of the control group brushed twice a day. In the oral examination, 70% had calculus, while in the control group only 22.5% presented calcified plaque. The DMFT was higher among the obesity group in comparison with the control group. Regarding periodontal disease, the participants with overweight need more dental intervention (81.4%) in contrast with the control group (14%).

Conclusions

Most overweight and obese individuals present precarious oral hygiene habits, higher prevalence of dental caries, and worse periods of periodontal health. They are not aware of the repercussions of the association between their cariogenic diet, oral health and overweight.

Key messages

• Oral health behaviors are related with other health conditions, namely obesity and this is a fundamental public health issue.

• Primary preventive strategies should be established having in consideration the oral health status of adults in treatment for obesity and in weight control programs.

Tuberculosis and Its “Troubled Relationship” With Other Diseases

Tuberculosis (TB) is a multisystemic disease caused most frequently by Mycobacterium tuberculosis. Extrapulmonary TB has become more frequent with the advent of human immunodeficiency virus (HIV) as HIV can facilitate the infection with M. tuberculosis, especially during HIV seroconversion. Here, we present the case of a 22-year-old man, from Guinea-Bissau, with a history of untreated HIV who was admitted to the intensive care unit for respiratory failure needing mechanical ventilation. Pulmonary TB was diagnosed. His stay was complicated with a hemorrhagic shock due to traumatic urethral catheterization, which led to a perforation of the capsule of the prostate. A prostatectomy was needed for bleeding control. The anatomopathological examination confirmed the presence of acid-resistant bacilli, and an extensive caseous type necrosis of the whole tissue, thus diagnosing a prostatic tuberculosis. The patient recovered after a hemorrhagic shock, a urologic and radical intervention, and some severe infectious complications.

Cysteine as a Multifaceted Player in Kidney, the Cysteine-Related Thiolome and Its Implications for Precision Medicine

In this review encouraged by original data, we first provided in vivo evidence that the kidney, comparative to the liver or brain, is an organ particularly rich in cysteine. In the kidney, the total availability of cysteine was higher in cortex tissue than in the medulla and distributed in free reduced, free oxidized and protein-bound fractions (in descending order). Next, we provided a comprehensive integrated review on the evidence that supports the reliance on cysteine of the kidney beyond cysteine antioxidant properties, highlighting the relevance of cysteine and its renal metabolism in the control of cysteine excess in the body as a pivotal source of metabolites to kidney biomass and bioenergetics and a promoter of adaptive responses to stressors. This view might translate into novel perspectives on the mechanisms of kidney function and blood pressure regulation and on clinical implications of the cysteine-related thiolome as a tool in precision medicine.

Pharmacological blockage of the AHR-CYP1A1 axis: a call for in vivo evidence

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that can be activated by structurally diverse compounds arising from the environment and the microbiota and host metabolism. Expanding evidence has been shown that the modulation of the canonical pathway of AHR occurs during several chronic diseases and that its abrogation might be of clinical interest for metabolic and inflammatory pathological processes. However, most of the evidence on the pharmacological abrogation of the AHR-CYP1A1 axis has been reported in vitro, and therefore, guidance for in vivo studies is needed. In this review, we cover the state-of-the-art of the pharmacodynamic and pharmacokinetic properties of AHR antagonists and CYP1A1 inhibitors in different in vivo rodent (mouse or rat) models of disease. This review will serve as a road map for those researchers embracing this emerging therapeutic area targeting the AHR. Moreover, it is a timely opportunity as the first AHR antagonists have recently entered the clinical stage of drug development.

An Unusual Cause of Knee Mass: Osseous Hydatidosis

Hydatid disease (hydatidosis) is a zoonotic infection caused by the larval stage of the parasitic tapeworm Echinococcus granulosus endemic in some sheep-raising areas. The liver and lungs are most commonly affected. Bone involvement (osseous hydatidosis) is distinctly uncommon, and its diagnosis and treatment can be challenging. We report a case of a 54-year-old male with right knee pain and edema and an extensive lesion on the femur; he was diagnosed with knee hydatidosis and was successfully treated with surgery and albendazole. This case reinforces the importance of the rare osseous hydatidosis as part of the differential diagnosis of bone lesions.

Self-perception of childrenś oral health by their parents

Background

Neglecting oral hygiene can lead to early tooth loss, pain, discomfort and, consequently, a great monetary investment to repair the damage caused in the stomatognathic system, whether of masticatory, phonetic or aesthetic origin. The aim of the present study consists in the characterization of oral health perception and oral hygiene habits of the children by their own parents and the creation of a scale to classify children's oral health perception by their parents.

Methods

A cross-sectional observational epidemiological study was performed. The population of this study was made up of 422 parents whose children are between five and eleven years of age and who attend schools in the districts of Viseu and Lisbon. The data collection was achieved through the application of a self-administered questionnaire in order to characterize the parentś perception of the oral health of their own children.

Results

Through the analysis of the questionnaires, 54.8% of the sample considered that their own children present inadequate oral health behaviors; 40.3% sufficient and only 4.8% consider that their children have good and adequate oral health behaviors. Regarding oral hygiene, most of the children did it one to five times a day, 44.7% took ‘2 minutes' to perform this activity, 70.3% did not use dental floss, 77.9% do not brush their teeth after lunch, 49.3% only use toothbrush for oral hygiene, 13.6% never went to the dentist, 26.9% are afraid, 38.1% have already suffered from toothache, 28.8% had gingival hemorrhage and 12.6% had gingival inflammation.

Conclusions

Oral health is a determining factor for a good quality of life. To this end, it is essential to implement oral health education and promotion strategies with all members of the household, in order to guarantee better oral health indexes in the community.

Key messages

Oral health literacy and knowledge is essential in order to improve oral health indexes in the community. The characterization of the oral health of children and adolescents is crucial to improve oral health behaviors and establish the correct oral health promotion programs.

Aryl Hydrocarbon Receptor and Cysteine Redox Dynamics Underlie (Mal)adaptive Mechanisms to Chronic Intermittent Hypoxia in Kidney Cortex

We hypothesized that an interplay between aryl hydrocarbon receptor (AhR) and cysteine-related thiolome at the kidney cortex underlies the mechanisms of (mal)adaptation to chronic intermittent hypoxia (CIH), promoting arterial hypertension (HTN). Using a rat model of CIH-HTN, we investigated the impact of short-term (1 and 7 days), mid-term (14 and 21 days, pre-HTN), and long-term intermittent hypoxia (IH) (up to 60 days, established HTN) on CYP1A1 protein level (a sensitive hallmark of AhR activation) and cysteine-related thiol pools. We found that acute and chronic IH had opposite effects on CYP1A1 and the thiolome. While short-term IH decreased CYP1A1 and increased protein-S-thiolation, long-term IH increased CYP1A1 and free oxidized cysteine. In addition, an in vitro administration of cystine, but not cysteine, to human endothelial cells increased Cyp1a1 expression, supporting cystine as a putative AhR activator. This study supports CYP1A1 as a biomarker of obstructive sleep apnea (OSA) severity and oxidized pools of cysteine as risk indicator of OSA-HTN. This work contributes to a better understanding of the mechanisms underlying the phenotype of OSA-HTN, mimicked by this model, which is in line with precision medicine challenges in OSA.

A Patient with Severe Malaria and COVID-19: How Do You Tell the Difference between These Infections?

Coronavirus infection, known as COVID-19, is characterized by clinical, epidemiological and biological features similar to those of malaria. In each case, fever, myalgia, fatigue, headaches and gastrointestinal symptoms may be present. Both diseases can also induce a cytokine storm and pro-coagulant states. An appropriate epidemiological approach and differential diagnosis are very important so that the right clinical intervention can be selected.

Malaria remains a serious global public health issue, especially in endemic countries. Elimination campaigns are helping to control the disease, but in many countries these programs are now at risk of failure due to logistic and economic problems caused by COVID-19.

The authors describe the case of a patient with co-infection with malaria and COVID-19, reminding us that during this coronavirus pandemic it is critical to consider other diagnoses, particularly in people traveling between countries.

Immune Thrombocytopenic Purpura - Different Presentations in Two COVID-19 Patients

Immune thrombocytopenic purpura (ITP) is a rare acquired autoimmune disease, resulting from platelet destruction and impaired platelet production. It has been described as associated with either genetic or environmental risk factors, such as viral infections, and in a few cases has been reported to be associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although steroid treatment is the most widely used first-line treatment of ITP, in the early days of coronavirus disease 2019 (COVID-19) it was controversial, but it has since become approved in treatment for COVID-19. The authors report two different cases of COVID-19-associated ITP, with special emphasis on the timing of presentation, severity, and treatment decisions. Remarkably, one of the patients who suffered severe thrombocytopenia was safely treated with corticosteroids in the late phase of COVID-19 infection.

Chemotaxonomic Profiling Through NMR1

A metabolite screening of cyanobacteria was performed by nuclear magnetic resonance (NMR) analysis of the soluble material obtained through sequential extraction of the biomass with three different extractive ability solvents (hexane, ethyl acetate, and methanol). Twenty-five strains from the Coimbra Collection of Algae (ACOI) belonging to different orders in the botanical code that represent three subsections of the Stainer-Rippka classification were used. The ¹ H NMR spectra of hexane extracts showed that only two strains of Nostoc genus accumulated triacylglycerols. Monogalactosyldiacylglycerols and digalactosyldiacylglycerols were the major components of the ethyl acetate extracts in a mono- to digalactosyldiacylglycerols ratio of 4.5 estimated by integration of the signals at δ 3.99 and 3.94 ppm (sn3 glycerol methylene). Oligosaccharides of sucrose and mycosporine-like amino acids, among other polar metabolites, were detected in the methanolic extracts. Strains of Nostocales order contained heterocyst glycolipids, whereas sulphoquinovosyldiacylglycerols were absent in one of the studied strains (Microchaete tenera ACOI 1451). Phosphathidylglycerol was identified as the major phospholipid in the methanolic extracts together with minor amounts of phosphatidylcholine based on ¹ H, ³¹ P 2D correlation experiments. Chemotaxonomic information could be easily obtained through the analysis of the δ 3.0-0.5 ppm (fatty acid distribution) and δ 1.2-1.1 ppm (terminal methyl groups of the aglycons in heterocyst glycolipids) regions of the ¹ H NMR spectra of the ethyl acetate and methanol extracts, respectively.

Women generating narratives after an unwanted prenatal diagnosis result: randomized controlled trial

We have defined a psychological intervention based on cognitive narrative therapy and the Ottawa decision framework to reduce adjustment problems following a termination of pregnancy (TOP) after a positive prenatal diagnosis (PND). The intervention is composed of four sessions: decision, subjectivation, metaphorization, and projecting. This study aims to assess the effectiveness of a cognitive narrative intervention to prevent depression and anxiety symptoms after TOP. The intervention was accepted by 24 participants. The outcome is compared with a control group of 67 women who also terminated a pregnancy after PND. Participants were from several Portuguese institutions; 64.4% had a genetic and 35.6% had ultrasound diagnosis; the mean age was 30.0 years and the mean gestational age was 19 weeks. There are two evaluations: a baseline at the 15th day and a sixth month follow-up after TOP, using Beck Depression Inventory, Zung Anxiety Scale, Perinatal Grief Scale, and an instrument capturing participant satisfaction. Six months after TOP, there is a lower mean of anxiety and depression (p < 0.05), between groups, with effect sizes on the follow-up of 0.54 for depression, 0.41 for anxiety, and 0.23 for perinatal grief. This intervention has very positive effects on women mental health, and we emphasize the importance of the meaning-making process in the context of terminating a wanted pregnancy.

Colloid centrifugation of fresh stallion semen before cryopreservation decreased microorganism load of frozen-thawed semen without affecting seminal kinetics

Freezability of equine semen may be influenced by microorganism population of semen. The objective of this study was to verify the effect of single-layer density gradient centrifugation (SLC) of fresh semen before cryopreservation on semen's microbial load (ML) and sperm cells kinetics after freezing-thawing. For that, one ejaculate was collected from 20 healthy stallions and split into control (C) samples (cryopreserved without previous SLC) and SLC samples (subjected to SLC). Semen cryopreservation was performed according to the same protocol in both groups. Microbial load of each microorganism species and total microbial load (TML) expressed in colony-forming units (CFU/mL) as well as frozen-thawed sperm kinetics were assessed in both groups. Additional analysis of the TML was performed, subdividing the frozen-thawed samples in "suitable" (total motility ≥ 30%) and "unsuitable" (total motility < 30%) semen for freezing programs, and comparing the C and SLC groups within these subpopulations. After thawing, SLC samples had less (P < 0.05) TML (88.65 × 10(2) ± 83.8 × 10(2) CFU/mL) than C samples (155.69 × 10(2) ± 48.85 × 10(2) CFU/mL), mainly due to a reduction of Enterococcus spp. and Bacillus spp. A relationship between post-thaw motility and SLC effect on ML was noted, as only in samples with more than 30% total motility was ML reduced (P < 0.05) by SLC (from 51.33 × 10(2) ± 33.26 × 10(2) CFU/mL to 26.68 × 10(2) ± 12.39 × 10(2) CFU/mL in "suitable" frozen-thawed semen vs. 240.90 × 10(2) ± 498.20 × 10(2) to 139.30 × 10(2) ± 290.30 × 10(2) CFU/mL in "unsuitable" frozen-thawed semen). The effect of SLC on kinetics of frozen-thawed sperm cells was negligible.

Effect of breeding activity on the microflora of the external genitalia and in the semen of stallions, and the relationship between micro-organisms on the skin and on the external genitalia

A possible role of breeding activities in the composition of the microbial population in stallions' external genitalia (EG) and the relationship between micro-organisms colonizing the skin of the abdomen and the ones colonizing the EG have not been studied. In experiment 1, EG microbiological samples were collected from 41 stallions used for both natural cover and semen collection (BST) and from 18 non-breeding stallions (NBST). A higher (p < 0.05) frequency of isolation of potentially pathogenic species was found for BST. Age did not influence number of micro-organism species isolated both in BST and NBST. In experiment 2, the microbial content of the EG and semen was compared in 23 BST. Most micro-organisms isolated from the EG were present in semen, albeit with a numerically lower prevalence. In 7 stallions, six microbial species isolated from semen were absent from the EG cultures, suggesting contamination by the operator. In experiment 3, a numerically higher number of micro-organism species was isolated from the EG of 31 stallions, than from their skin of the ventral abdomen in contact with the penis or from the skin of the thorax. With the sole exception of Escherichia coli, potentially pathogenic bacteria were only isolated from the EG but not from the skin. Results suggest that breeding activity increased the number of species colonizing the EG; most species isolated from the EG were also found in semen even if with a lower frequency, and additional semen contamination seemed to occur during its manipulation. Many micro-organism species of the skin were also isolated from the penis, but independently of being or not in contact with the penis, skin did not seem to provide an adequate environment for the growth of potentially pathogenic bacteria that were isolated from EG, with the sole exception for E. coli.

Effective energy barrier distributions for random and aligned magnetic nanoparticles

Isothermal magnetic relaxation measurements are widely used to probe energy barriers in systems of magnetic nanoparticles. Here we show that the result of such an experiment can differ greatly for aligned and randomly oriented nanoparticles. For randomly oriented cobalt-doped magnetite nanoparticles we observe a prominent low-energy tail in the energy barrier distribution that is greatly attenuated when the particles are magnetically aligned. Monte Carlo simulations show that this behaviour arises for nanoparticles with both cubic and uniaxial magnetic anisotropy energy terms even though for cubic or uniaxial anisotropy alone the energy barrier distribution is independent of nanoparticle orientation.

Effects of body condition and leptin on the reproductive performance of Lusitano mares on extensive systems

The aim of this study was to investigate the effects of body condition (BC), BC changes, and plasma leptin concentrations on the reproductive performance of Lusitano broodmares on extensive systems. Data from 119 mares (ranging from 4 to 22 years of age) were collected over a period of four consecutive breeding seasons. Each case was considered as one foaled mare bred in 1 year. Body condition changes at conception (ΔBCScon) showed a strong effect on fertility at the first two postpartum estrous cycles and a significant interaction with body condition score at conception (BCScon) was observed (P < 0.01). The best fertility results were obtained with positive and greater ΔBCScon. The best predictive value of fertility (91%) was achieved when the BCScon was 3.0 and ΔBCScon was 0.375. Global foaling rate for the 4-year period was 74.5%. Mean foaling interval and gestation length were, respectively, 368.0 ± 2.8 and 340.3 ± 1.0 days. Gestation length was influenced by the month of foaling (P < 0.05) and decreased as mares got older (P < 0.01). The number of estimated estrous cycles per live foal was 1.78 ± 0.12, including foal heat ovulation. Leptin was correlated with BCS (0.41; P < 0.001), but in the present study, plasma leptin concentrations on late gestation and early lactation did not influence fertility results. At 90 days of age, lower growth performances were obtained in foals which dams presented negative BCS changes on the first 3 months of lactation (P < 0.05). In conclusion, BC changes at early postpartum period influence the reproductive efficiency of broodmares and the growth of their suckling foals. These findings are important to help breeders on management options concerning feeding strategies in the Lusitano production systems and others under similar conditions.

Detection of early sub-clinical trastuzumab-induced cardiotoxicity in breast cancer patients

BACKGROUND

Trastuzumab (TZB) is a recombinant humanized monoclonal antibody, used for the treatment of HER2-positive breast cancer, with recognized associated-cardiotoxicity. The methods for its early sub-clinical detection are not well defined.

OBJECTIVE

To evaluate TZB-induced cardiotoxicity in patients (pts) with breast cancer followed for a 3-month period of treatment.

METHODS

Prospective study of consecutive pts treated with TZB for advanced HER2-positive breast cancer enrolled between May-September/2010. A comparison of clinical, laboratory and echocardiographic data, prior to and at the 3rd month after starting TZB was performed. Left ventricular systolic function deterioration (Cardiac Review and Evaluation Committee criteria) and diastolic function (American Society of Echocardiography classification) were studied.

RESULTS

Data were available for 51 women, mean age = 55.4 ± 14.0y. At the 3rd month, no patient had symptomatic heart failure. Left ventricular ejection fraction (LVEF) did not differ at 3 months (69.3 ± 7.4 vs. 67.1 ± 6.5%, p > 0.05), decreasing in 57.9% pts (only one to LVEF < 55%). There was a significant increase in the E/e' ratio (3.9 ± 0.8 vs. 8.0 ± 1.9, p < 0,001) due to an e' velocity reduction (0.19 ± 0.02 vs. 0.10 ± 0.03, p < 0.001). Other diastolic parameters remained unchanged. Both the left atrial and the left ventricular volumes remained unchanged. N-terminal pro-B type natriuretic peptide levels did not increase. During the follow up period two pts died and two were admitted to the hospital, all for non-cardiovascular causes.

CONCLUSIONS

During the first 3 months of TZB treatment none of the pts presented overt heart failure or significant LVEF deterioration. A significant reduction in the E/e' ratio was detected, but neither the loading parameters nor LVEF changed significantly .

[NT-proBNP for risk stratification of pulmonary embolism]

INTRODUCTION

Pulmonary embolism (PE) is an entity with high mortality and morbidity, in which risk stratification for adverse events is essential. N-terminal brain natriuretic peptide (NT-proBNP), a right ventricular dysfunction marker, may be useful in assessing the short-term prognosis of patients with PE.

AIMS

To characterize a sample of patients hospitalized with PE according to NT-proBNP level at hospital admission and to assess the impact of this biomarker on short-term evolution.

METHODS

We performed a retrospective analysis of consecutive patients admitted with PE over a period of 3.5 years. Based on the median NT-proBNP at hospital admission, patients were divided into two groups (Group 1: NT-proBNP<median and Group 2: NT-proBNP ≥ median). The two groups were compared in terms of demographic characteristics, personal history, clinical presentation, laboratory, electrocardiographic and echocardiographic data, drug therapy, in-hospital course (catecholamine support, invasive ventilation and in-hospital death and the combined endpoint of these events) and 30-day all-cause mortality. A receiver operating characteristic (ROC) curve was constructed to determine the discriminatory power and cut-off value of NT-proBNP for 30-day all-cause mortality.

RESULTS

Ninety-one patients, mean age 69±16.4 years (51.6% aged ≥75 years), 53.8% male, were analyzed. Of the total sample, 41.8% had no etiological or predisposing factors for PE and most (84.6%) were stratified as intermediate-risk PE. Median NT-proBNP was 2440 pg/ml. Patients in Group 2 were significantly older (74.8±13.2 vs. 62.8±17.2 years, p=0.003) and more had a history of heart failure (35.5% vs. 3.3%, p=0.002) and chronic kidney disease (32.3% vs. 6.7%, p=0.012). They had more tachypnea on initial clinical evaluation (74.2% vs. 44.8, p=0.02), less chest pain (16.1% vs. 46.7%, p=0.01) and higher creatininemia (1.7±0.9 vs. 1.1±0.5mg/dl, p=0.004). Group 2 also more frequently had right chamber dilatation (85.7% vs. 56.7%, p=0.015) and lower left ventricular ejection fraction (56.4±17.6% vs. 66.2±13.5%, p=0.036) on echocardiography. There were no significant differences in drug therapy between the two groups. Regarding the studied endpoints, Group 2 patients needed more catecholamine support (25.8% vs. 6.7%, p=0.044), had higher in-hospital mortality (16.1% vs. 0.0%, p=0.022) and more frequently had the combined endpoint (32.3% vs. 10.0%, p=0.034). All-cause mortality at 30 days was seen only in Group 2 patients (24.1% vs. 0.0%, p=0.034). By ROC curve analysis, NT-proBNP had excellent discriminatory power for this event, with an area under the curve of 0.848. The best NT-proBNP cut-off value was 4740 pg/ml.

CONCLUSION

Elevated NT-proBNP levels identified PE patients with worse short-term prognosis, and showed excellent power to predict 30-day all-cause mortality. The results of this study may have important clinical implications. The inclusion of NT-proBNP measurement in the initial evaluation of patients with PE can add valuable prognostic information.

Elementary properties of Kir2.1, a strong inwardly rectifying K(+) channel expressed by pigeon vestibular type II hair cells

By using the patch-clamp technique in the cell-attached configuration, we have investigated the single-channel properties of an inward rectifier potassium channel (Kir) expressed by pigeon vestibular type II hair cells in situ. In high-K(+) external solution with 2 mM Mg(2+), Kir inward current showed openings to at least four amplitude levels. The two most frequent open states (L2 and L3) had a mean slope conductance of 13 and 28 pS, respectively. L1 (7 pS) and L4 (36 pS) together accounted for less than 6% of the conductive state. Closed time distributions were fitted well using four exponential functions, of which the slowest time constant (tau(C4)) was clearly voltage-dependent. Open time distributions were fitted well with two or three exponential functions depending on voltage. The mean open probability (P(O)) decreased with hyperpolarization (0.13 at -50 mV and 0.03 at -120 mV). During pulse-voltage protocols, the Kir current-decay process (inactivation) accelerated and increased in extent with hyperpolarization. This phenomenon was associated with a progressive increase of the relative importance of tau(C4). Kir inactivation almost disappeared when Mg(2+) was omitted from the pipette solution. At the same time, P(O) increased at all membrane voltages and the relative importance of L4 increased to a mean value of 47%. The relative importance of tau(C4) decreased for all open states, while L4 only showed a significantly longer open time constant. The present work provides the first detailed quantitative description of the elementary properties of the Kir inward rectifier in pigeon vestibular type II hair cells and specifically describes the Kir gating properties and the molecule's sensitivity to extracellular Mg(2+) for all subconductance levels. The present results are consistent with the Kir2.1 protein sustaining a strong inwardly rectifying K(+) current in native hair cells, characterized by rapid activation time course and slow partial inactivation. The longest closed state (tau(C4)) appears as the main parameter involved in time- and Mg(2+)-dependent decay. Finally, in contrast to Kir2.1 results described so far for mammalian cells, external Mg(2+) had no effect on channel conductance.

Kvbeta1.1 associates with Kvalpha1.4 in Chinese hamster ovary cells and pigeon type II vestibular hair cells and enhances the amplitude, inactivation and negatively shifts the steady-state inactivation range

Although A-type potassium currents are found in type II hair cells in the inner ear of most species, the molecular mechanisms for activation and inactivation of the A-type potassium current (I(A)) remain unknown. In frog semicircular canal hair cells, for example, there appear to be two classes of currents having either fast or slow inactivation [Norris CH, Ricci AJ, Housley GD, Guth PS (1992) The inactivating potassium currents of hair cells isolated from the crista ampullaris of the frog. J Neurophysiol 68:1642-1653; Russo G, Calzi D, Martini M, Rossi ML, Fesce R, Prigioni I (2007) Potassium currents in the hair cells of vestibular epithelium: position-dependent expression of two types of A channels. Eur J Neurosci 25:695-704]. It has been suggested that somehow the "ball and chain" mechanism (NH(3) (N) terminus motif) is modified by alternative splicing to account for the two classes of inactivation. To examine other possibilities, we cloned alpha and beta subunits that comprise the A-type potassium channel complex in adult and embryonic pigeon brain, cochlea and labyrinth. By sequence homology, we concluded that the subunits present were Kvalpha1.4 and Kvbeta1.1. The sequence of the open reading frame for Kvalpha1.4 contained the N-terminus, pore and COOH (C) terminus motifs for N-and C-type inactivation. The sequence for Kvbeta1.1 displayed amino acids consistent with assembly and association with Kvalpha1.4 alpha subunits. Kvalpha1.4 and Kvbeta1.1 were transfected either singly or in combination into Chinese hamster ovary (CHO) cells. These cells and native hair cells from the pigeon utricle were patch clamped and the inactivation properties of the A-type current were studied. In the native hair cells, the A-type current was identified by its pharmacological (4-aminopyridine (4-AP); IC(50)=11 microM) and voltage dependent inactivation properties. A comparison of the mean time constants from best-fitted single exponential and sum of two exponential equations to the ionic current inactivation revealed the following. In CHO cells when Kvalpha1.4 was expressed alone, the mean time constant (tau(1)=107 ms+/-19, N=32) was significantly (P<0.001) longer and the mean peak amplitude (2.28 nA+/-0.39, N=32) was smaller than when Kvalpha1.4 and Kvbeta1.1 were expressed in CHO cells. Moreover, the co-transfection of Kvalpha1.4 and Kvbeta1.1 into CHO cells caused a shift in the steady state inactivation curve parameter Vo 30 mV in the hyperpolarized direction relative to CHO cells expressing only Kvalpha1.4. Similarly, Kvalpha1.4-transfected CHO cells produced longer time constants and smaller amplitudes than those found for native utricular hair cells. These data lead us to conclude that while the amino acid motifs are present in Kvalpha1.4 and Kvbeta1.1 to suggest N-and C-type inactivation, co-assembly and association of Kvalpha1.4 and Kvbeta1.1 may also produce changes in the time dependent inactivation properties of vestibular hair cells.

Effects of soil drying and subsequent re-watering on the activity of nitrate reductase in roots and leaves of Helianthus annuus

The effects of drought on the activity of nitrate reductase (NR) were studied in Helianthus annuus L. plants subjected to soil drying and subsequent re-watering. Drought did not negatively affect the activation state of NR, but resulted in linearly-correlated decreases in the activity of the unphosphorylated active form and the total activity of NR, in both roots and leaves. The concentration of nitrate in roots, xylem and leaves also decreased in water-stressed plants, whereas the concentration of total amino acids was only transiently depressed at the leaf level. In contrast, soluble sugars accumulated both in roots and leaves of water-stressed plants. Drought-induced decreases in root NR activity were correlated with the observed changes in root nitrate concentration. A higher percentage of the decrease in foliar NR activity could be explained by the decline in nitrate flux to the leaves than by leaf nitrate content. Following re-watering, the extent of recovery of NR activity was higher in roots than in leaves. The delay in the recovery of foliar NR activity did not result from the persistence of reduced flux of nitrate through the xylem. Several hypotheses to explain the after-effect of soil drying on foliar NR activity are discussed.

Acute coronary syndromes in smokers: clinical and angiographic characteristics

Smoking is a major and reversible risk factor for coronary artery disease. The present work aims to define the risk factors, angiographic and clinical characteristics and evolution of acute coronary syndromes in smokers.

METHODS

We studied 521 consecutive patients with acute coronary syndrome admitted to the intensive care unit who underwent catheterization. We assessed the population in terms of risk factors, pathology (unstable angina or acute myocardial infarction), coronary morphology, left ventricular function, the need for intervention, evolution and complications over a one-year period. The characteristics of smokers were then compared with those of non-smokers.

RESULTS

Of the 521 patients with acute coronary syndrome (391 men), 182 (35 %) were smokers. The smokers were younger than the non-smokers (56.3+/-9.5 versus 66.4 +/- 7.8; p < 0.001), were more frequently male (91 versus 66%; p < 0.001), and presented more risk factors (43% with 3 or more risk factors versus 17% in non-smokers; p < 0.001), more obesity (11 versus 5%; p < 0.01), and less diabetes (19 versus 37%; p < 0.001). Smokers presented greater prevalence of acute myocardial infarction (57 versus 40%; p < 0.001) and less unstable angina. Coronary morphology was not significantly different in smokers compared to non- smokers and left ventricular function after the aculte coronary syndrome was similar in both groups. Smokers less frequently underwent surgery during hospitalization (22% versus 35%; p < 0.01) but needed angioplasty as often as non-smokers (48% versus 16%; NS). Smokers presented more frequent complications (angina, heart failure, re-infarction or CABG) than non-smokers (26% versus 17%; p < 0.01), during the first year of follow-up. One-year mortality was similar in both groups. The results were not significantly different when adjusted for gender.

CONCLUSIONS

On average, acute coronary syndrome occurred 10 years earlier in smokers than in non-smokers. The former generally presented more risk factors, lower prevalence of diabetes and higher of obesity, more myocardial infarctions and less unstable angina. After the acute coronary syndrome, at one year, smokers presented more complications than non-smokers but had similar mortality.

Percentage of coronary anomalies in a population of patients undergoing coronary angiography: a retrospective study

Coronary artery anomalies, although less frequent than congenital anomalies of the heart chambers and valve morphology, should be considered in a wide range of ages, in both sexes and as a possible etiology in myocardial ischemia, infarction, and sudden death, as well as in the planning of heart surgery for coronary revascularization, correction of congenital heart malformations or valve replacement. Between January 1996 and June 2002 we reviewed our catheterization database and carried out a retrospective study of the 3660 angiographies performed in our cardiology department. The patients were referred for positive ischemic test, acute coronary syndrome and/or valvular heart disease. From the 3660 angiographies we identified 25 patients (0.68%) with coronary artery anomalies and report the prevalence and types of these anomalies in the population studied. We also assessed the presence of coronary artery disease.

Left main coronary artery originating in the right sinus of Valsalva

A forty-one-year-old male, with no risk factors for coronary artery disease (CAD) and with moderate alcohol intake, was admitted in 1992 to Portalegre Hospital with heart failure due to viral cardiomyopathy. He was re-admitted in 1998 with acute pulmonary edema and was put on mechanical ventilation for 48 hours, and transferred to Pulido Valente Hospital when stable. The physical exam was without abnormalities. ECG showed first degree AV block, left ventricular hypertrophy and 2 mm ST depression in the precordial leads. The echocardiogram revealed left ventricular dilatation and depressed systolic function. Coronary angiography showed single-vessel CAD and coronary artery anomaly. Dobutamine stress echocardiography was halted due to hypertension, making it impossible to evaluate ischemic response. Holter monitoring showed five-complex ventricular tachycardia. The patient was discharged medicated with amiodarone, with indication for cardiac scintigraphy and electrophysiological study.

Acute coronary syndrome in a diabetic population--risk factors and clinical and angiographic characteristics

INTRODUCTION

Diabetes is not only a risk factor for coronary artery disease but also influences its presentation and evolution.

OBJECTIVES

The objective of this work is to define the risk factors, clinical and angiographic characteristics, and evolution of acute coronary syndrome in a population of diabetic patients.

METHODOLOGY

We studied 521 patients suffering from acute coronary syndrome, consecutively hospitalized in the Cardiology Intensive Care Unit who underwent cardiac catheterization during their hospitalization, in terms of risk factors for coronary disease, pathology (unstable angina versus acute myocardial infarction), coronary morphology, left ventricular function, need for intervention during hospitalization, evolution and complications during one-year follow-up. The characteristics of the diabetic patients with acute coronary syndrome were compared to those of non-diabetic patients.

RESULTS

Of the 521 patients suffering from acute coronary syndrome (391 male), 159 (30.5%) were diabetic. The diabetic patients suffering from acute coronary syndrome generally presented fewer risk factors for coronary artery disease, with a lower prevalence of smoking (p < 0.001), greater prevalence of family history of coronary artery disease (p < 0.01), more unstable angina and less acute myocardial infarction (both p < 0.001), than the nondiabetic patients. After the acute coronary syndrome the diabetic patients more frequently presented disease of the left anterior descending artery, left ventricular function was worse and there was a greater need for coronary artery bypass graft surgery and less percutaneous transluminal coronary angioplasty than in the non-diabetic patients (p < 0.05 for all). In terms of evolution, they presented greater complications and more mortality over a year (p < 0.05).

CONCLUSION

Diabetes constitutes a powerful risk factor for coronary artery disease and its complications, and should therefore be taken into consideration in clinical approaches to this pathology.

Na+ currents in vestibular type I and type II hair cells of the embryo and adult chicken

In birds, type I and type II hair cells differentiate before birth. Here we describe that chick hair cells, from the semicircular canals, begin expressing a voltage-dependent Na current (INa) from embryonic day 14 (E14) and continue to express the current up to hatching (E21). During this period, INa was present in most (31/43) type I hair cells irrespective of their position in the crista, in most type II hair cells located far from the planum semilunatum (48/63), but only occasionally in type II hair cells close to the planum semilunatum (2/35). INa activated close to -60 mV, showed fast time- and voltage-dependent activation and inactivation, and was completely, and reversibly, blocked by submicromolar concentrations of tetrodotoxin (Kd = 17 nM). One peculiar property of INa concerns its steady-state inactivation, which is complete at -60 mV (half-inactivating voltage = -96 mV). INa was found in type I and type II hair cells from the adult chicken as well, where it had similar, although possibly not identical, properties and regional distribution. Current-clamp experiments showed that INa could contribute to the voltage response provided that the cell membrane was depolarized from holding potentials more negative than -80 mV. When recruited, INa produced a significant acceleration of the cell membrane depolarization, which occasionally elicited a large rapid depolarization followed by a rapid repolarization (action-potential-like response). Possible physiological roles for INa in the embryo and adult chicken are discussed.

Risk factors and clinical angiographical characteristics of myocardial infarction in women

INTRODUCTION

Myocardial infarction has a higher incidence in men. However, in women, although less frequent, it has a worse prognosis.

OBJECTIVE

With the present work we aim to define the clinical and angiographical characteristics and evolution of myocardial infarction in women compared with men.

METHODOLOGY

We studied 235 sequential inpatients with acute myocardial infarction in the Intensive Care Unit who underwent post-infarction catheterization. We then compared female with male patients in terms of risk factors, location and type of infarction, coronary morphology and post-infarction complications.

RESULTS

About 22% of the patients hospitalized following myocardial infarction were female. The women were older than the men (65.9 +/- 11.2 vs. 60.3 +/- 11.9; p < 0.01), and had a higher prevalence of high blood pressure (71% vs. 54%, p < 0.05) and a lower prevalence of smoking (19% vs. 50%, p < 0.001). Post-infarction angina was more frequent in women (50% vs. 23%, p < 0.001). Neither Q-wave versus non-Q wave myocardial infarction nor its location were significantly different between the sexes. In terms of coronary morphology, myocardial infarction without significant lesions was more frequent in women (10% vs. 3%, p < 0.05) and there were no significant.

Tissue Doppler imaging and long axis left ventricular function: hypertrophic cardiomyopathy versus athlete's heart

BACKGROUND

The different diagnosis between hypertrophic cardiomyopathy and athlete's heart has important clinical implications. The assessment of long axis left ventricular function with tissue Doppler imaging in hypertrophic cardiomyopathy (showing systolic and diastolic dysfunction with heterogeneity and asynchrony), may be useful in the differentiation of these situations.

AIM

To study, with tissue Doppler imaging, long axis left ventricular function in a population of athletes (rowers) and to compare it with a population of non-obstructive hypertrophic cardiomyopathy patients.

METHODS

In 24 patients with non-obstructive hypertrophic cardiomyopathy and in 20 competitive rowers with similar age, blood pressure and heart rate, we analyzed mitral annulus motion with pulsed tissue Doppler imaging in the 4 sides of the annulus (septal, lateral, inferior, anterior), in apical views. In each wave (systolic, rapid filling and atrial contraction) we measured velocities, time intervals and velocity-time integrals, and calculated heterogeneity and asynchrony indices. Data were compared between the groups, between the different sides in each group ("parallel analysis") and with conventional indices of global function.

RESULTS

Hypertrophic cardiomyopathy patients showed: systolic function: lower velocities and integrals, shorter ejection time and shorter systolic time. These abnormalities occurred even in annular sites contiguous to walls without hypertrophy. DIASTOLIC FUNCTION: Much lower rapid filling velocities and integrals, lower atrial contraction velocities and integrals, lower e/a, longer isovolumic relaxation time and time to peak rapid filling wave. These abnormalities occurred even in annular sites adjacent to walls without hypertrophy. In the athletes group, the e/a ratio was never < 1, in any annular site. In hypertrophic cardiomyopathy patients this ratio was < 1 in 27% of the sites.

CONCLUSIONS

1--Systolic and diastolic long axis left ventricular function is different in hypertrophic cardiomyopathy and in athletes, in all mitral annulus sides. 2--The presence of these abnormalities in annular sites contiguous to walls without hypertrophy suggests that this technique may be useful in the differential diagnosis between these groups, particularly in the "gray zone" of Maron.

Homocysteine increase after acute myocardial infarction--can it explain the differences between case-control and cohort studies?

Several case-control studies agree that elevated homocysteinemia (HC) is a risk factor for cardiovascular disease, particularly for acute myocardial infarction (AMI). However, this agreement does not extend to prospective studies--some of which confirm and others (MRFIT and Karelia) reject this relation. After an AMI there are significant changes in biochemical and laboratory parameters, including a decrease in cholesterolemia, which takes several months to return to baseline levels. The evolution of HC after AMI is still unknown. In this work we set out to evaluate the evolution of homocysteinemia values after acute myocardial infarction. We evaluated fasting homocysteinemia in 34 sequential patients after admission to the Intensive Care Unit and after confirmation of acute myocardial infarction (26 male; mean age 63.8 +/- 13.9 years) in the first 36 hours, between the 3rd and 6th day, and one month after AMI. Simultaneously, we studied traditional risk factors and performed routine laboratory tests. The mean values found for HC were 13.85 +/- 5.46 mol/l in the first 36 hours after AMI, 16.16 +/- 6.63 mol/l between the 3rd and the 6th day, and 16.27 +/- 7.27 mol/l one month after myocardial infarction. The difference between the first and the second, and between the first and the third measurements, was significant (p < 0.05). The HC values found 3-6 days and one month after myocardial infarction were similar (p = 0.88). A highly significant correlation was found between HC values assessed in the first and second (correlation coefficient [CC] = 0.62) and in the second and third measurements (CC = 0.57), both with p = 0.001. We can conclude that HC levels increase significantly 36 hours after an acute myocardial infarction, an increase of around 20%, which is maintained until at least one month after the infarction. In these circumstances the difference in the vascular risk of HC found between case-control and prospective studies may be explained, at least partially, by the HC increase after AMI.

Return of potassium ion channels in regenerated hair cells: possible pathways and the role of intracellular calcium signaling

Recent electrophysiological studies in pigeon have demonstrated that potassium channels are completely functional in regenerated type II hair cells at 21 days post-treatment (PT) with ototoxic doses of streptomycin. The currents return in the order they appear during development. The mixture of ionic currents in a regenerated type II hair cell in a particular region of the neuroepithelium is the same as in its ancestor in that region. The return of currents in regenerated type I hair cells is more complicated. The dominant conductance gKI is not present until after 70 days PT. Before 70 days, the ionic currents in type I hair cells resemble those of regenerated type II hair cells, suggesting that the ionic currents in type II hair cells might be precursors of the ionic currents in regenerated type I hair cells. New data show that at one year PT, the kinetics and drug sensitivity of the dominant K+ conductance in type I hair cells are identical to gKI. Supporting cells, believed to be the precursors of regenerated type II hair cells, have effectively no voltage-gated outward potassium channels, suggesting that regenerated type II hair cells must develop these channels de novo. The next step is to understand the mechanisms by which the potassium channel protein is synthesized, migrates through the cytosol, and is inserted into the plasmalemma of regenerating hair cells. These mechanisms are unknown. We propose that intracellular calcium is involved in this process, as well as in the differentiation, proliferation, and gene regulation of precursor cells fated to become hair cells.

Response to seasonal drought in three cultivars of Ceratonia siliqua: leaf growth and water relations

Responses of leaf growth and leaf water relations to seasonal drought were monitored during two successive years in three cultivars (Galhosa, Espargal and Mulata) of Ceratonia siliqua L. growing in the field in southern Portugal. Leaf water relations of fully expanded leaves were characterized by pressureâ volume analysis, and morphometric measurements of petiolar xylem were made. The three cultivars differed with respect to onset of leaf initiation. In Galhosa, there was a sharp peak of leaf initiation in June that was immediately followed by a period when leaf expansion rates were highest. The onset of leaf growth occurred earlier in Espargal and Mulata than in Galhosa, and both cultivars continued producing new leaves throughout the summer period. The diurnal pattern of water relations in recently expanded leaves indicated that, during midsummer, Galhosa was the only cultivar in which leaf water potential did not fall below the turgor loss point and leaf relative water content remained above 90%. The occurrence of osmotic adjustment in recently expanded leaves of Galhosa was not demonstrated conclusively. However, during the dry season following leaf formation, a seasonal decrease in osmotic potential sufficient to maintain turgor was detected in 1-year-old leaves of Galhosa but not in 1-year-old leaves of the other cultivars. Among cultivars, Galhosa petioles had the widest xylem conduits, which may partly explain why midday leaf water potential in Galhosa never decreased below -2.0 MPa even at the end of the summer drought.

[Can blood homocysteine explain the family history of vascular diseases?]

INTRODUCTION AND AIMS

Family history of vascular disease is an important risk factor for vascular disease, independent of conventional risk factors. Homocysteinemia, a newly defined risk factor, is caused by genetics, such as cystathionine beta synthase deficiencies, and metabolic deficiencies. With the present work we intend to study the influence of family history of vascular disease in homocysteinemia.

METHODS

We studied 204 normal persons (153 males), average age 38.7 +/- 10.9 years, in terms of family history of vascular disease (death due to myocardial infarction or a stroke), conventional risk factors, routine laboratory tests, fasting homocysteinemia and after oral methionine loading (0.1 g/Kg body weight). We compared laboratory results, conventional risk factors and homocysteinemia levels in persons with and without a family history of vascular disease. We performed covariance analysis to evaluate, in a multivariate model, factors that were related to basal or after methionine loading homocysteinemia.

RESULTS

35% of persons presented a family history of vascular disease (FHVD). Persons with FHVD presented higher age (45.6 +/- 8.9 versus 35.0 +/- 10.1, p < 0.001), and higher prevalence of hypertension (p = 0.002), dyslipidemia (p = 0.001), obesity (p = 0.03), and physical inactivity (p = 0.03). They presented a tendency, without statistical significance, to have a higher prevalence of diabetes and of hyperhomocysteinemia, and to present higher levels of basal and afterload homocysteinemia. Performing covariance analysis, basal homocysteinemia did not present any relation to FHVD. After methionine load homocysteinemia was strongly influenced by basal homocysteinemia (p = 0.0000), and significantly related to FHVD (p = 0.039).

CONCLUSIONS

Homocysteinemia cannot explain most of the risk of family history of vascular disease, not explained by conventional risk factors. The only significant relationship between homocysteinemia and FHVD was observed with afterload homocysteinemia in the multivariate model. FHVD is clearly related to conventional risk factors.

[Secondary prevention in acute myocardial infarction]

Myocardial infarction is still one of the main causes of mortality and morbidity in Western countries. The advances made in the last 30 years have made it possible to reduce mortality significantly (which is currently below two digits) as well as morbidity. The subject of secondary prevention of myocardial infarction gains particular significance in this context since 10 to 15% of the patients who survive the hospital phase of myocardial infarction die during the first year following discharge and, of these deaths, half occur in the first three months. Therefore, it is necessary to make an early definition of the risk of another coronary event, that is, to make a risk stratification. This should occur throughout hospitalization and should be complete at the time of discharge, never beyond the first weeks of evolution. Bearing in mind the age, sex, coronary risk factors, ischemia persistence, the degree of left ventricular dysfunction and the presence of malignant disrhythmias, there are three risk levels: high; intermediate; and low. An overall approach to secondary prevention of infarction should take into account that, apart from the factors of such high prognostic value (Chapter II) assessed in the definition of risk groups, the measures to reduce reinfarction and sudden death (Chapter III) and the control of the risk factors for heart disease (Chapter IV) should also be considered. The principal late complications of infarction with significant prognostic influence are described in Chapter III: left ventricular dysfunction; rhythm disturbances and residual ischemia. The diagnostic criteria and therapeutic objectives are considered in each of the groups with relevance to consolidated advances according to the modern concept of evidence based medicine, according to international regulations. The grading of scientific evidence into three distinct categories (A, B and C), based on five levels of evidence classified from I to V, is presented accordingly in relation to the therapeutic proposals. Chapter III deals with a set of therapeutic interventions used in secondary prevention because they reduce reinfarction and sudden death: platelet antiaggregants; anticoagulants; Beta blockers; calcium channel blockers; antioxidants and nitrates. A concept of particular clinical significance is presented for each of these groups of drugs. The last part contains an eminently clinical overall review of the principal advances in coronary risk factor control, new therapeutic acquisitions in atherosclerotic disease with natural relevance to hypolipidemic agents and statins, which apart from controlling the plasmatic levels of cholesterol, also stabilize the atherosclerotic plaque and reduce acute coronary events significantly. Apart from dyslipidemia, the classic risk factors are: smoking; hypertension; obesity; diabetes and sedentary life. In each case, reference is made to the general measures and specific approaches, as well as the pharmacological therapy according to evidence based medicine. The recommended attitudes are pointed out. The role of cardiac rehabilitation and postmenopausal hormone replacement therapy are also discussed in the last part of these recommendations, in which the on-going controversy regarding hormone replacement therapy is pointed out in view of the results of more recent clinical trials.

Effects of KCNQ channel blockers on K(+) currents in vestibular hair cells

Linopirdine and XE991, selective blockers of K(+) channels belonging to the KCNQ family, were applied to hair cells isolated from gerbil vestibular system and to hair cells in slices of pigeon crista. In type II hair cells, both compounds inhibited a slowly activating, slowly inactivating component of the macroscopic current recruited at potentials above -60 mV. The dissociation constants for linopirdine and XE991 block were <5 microM. A similar component of the current was also blocked by 50 microM capsaicin in gerbil type II hair cells. All three drugs blocked a current component that showed steady-state inactivation and a biexponential inactivation with time constants of approximately 300 ms and 4 s. Linopirdine (10 microM) reduced inward currents through the low-voltage-activated K(+) current in type I hair cells, but concentrations up to 200 microM had little effect on steady-state outward K(+) current in these cells. These results suggest that KCNQ channels may be present in amniote vestibular hair cells.

Hair cell and supporting cell density and distribution in the normal and regenerating posterior crista ampullaris of the pigeon

The numbers of supporting cells and the numbers and types of hair cells in three distinct longitudinal regions through the posterior canal cristae of control and streptomycin-treated pigeons were determined using stereological techniques. For control cristae, type I (3758) and type II (3517) hair cells occurred in approximately equal numbers. However, the proportions varied in different longitudinal zones: Zone I (peripheral region) had four times more type II hair cells (2083) than type I (483), while Zone II (intermediate region) had almost seven times more type I (2517) than type II (367) hair cells and Zone III (central region) had relatively equal numbers of type I (758) and type II (1067) hair cells. Novel findings included the following: (1) immediately after the post-injection sequence (PIS) of streptomycin, there was a significant reduction in both hair cells (-93%) and supporting cells (-45%); (2) by 70 days after the PIS, the population of type I hair cells returned to control values (however, the normal complement of complex calyces took 1 year to recover); (3) during the first 143 days after the PIS, the number of type I and type II hair cells across all zones returned linearly with about the same slope (46 and 43 cells per day, respectively), although the rate of return differed significantly in different zones; (4) there was a massive overproduction of hair cells (+150%) and supporting cells (+120%) during the first 5 months of recovery; and (5) during the first year after the PIS, both hair cells and supporting cells increased and their increases in numbers were correlated (r = 0.88, P < 0.01). Knowledge of the sequence and numbers of regenerating hair cells may help elucidate common modes of cell survival, recovery, and compensation from neural insult.

Effects of cationic substitutions on delayed rectifier current in type I vestibular hair cells

The resting potassium current (I(KI)) in gerbil dissociated type I vestibular hair cells has been characterized under various ionic conditions in whole cell voltage-clamp. When all K(+) in the patch electrode solution was replaced with Na(+), (Na(+))(in) or Cs(+), (Cs(+))(in), large inward currents were evoked in response to voltage steps between -90 and -50 mV. Activation of these currents could be described by a Hodgkin-Huxley-type kinetic scheme, the order of best fit increasing with depolarization. Above approximately -40 mV currents became outward and inactivated with a monoexponential time course. Membrane resistance was inversely correlated with external K(+) concentration. With (Na(+))(in), currents were eliminated when K(+) was removed from the external solution or following extracellular perfusion of 4-aminopyridine, indicating that currents flowed through I(KI) channels. Also, reduction of K(+) entry through manipulation of membrane potential reduced the magnitude of the outward current. Under symmetrical Cs(+), 0 K(+) conditions I(KI) is highly permeable to Cs(+). However, inward currents were reduced when small amounts of external K(+) were added. Higher concentrations of K(+) resulted in larger currents indicating an anomalous mole fraction effect in mixtures of external Cs(+) and K(+).

Extra-adrenal pheochromocytoma (paraganglioma)

The authors describe the case of a 19-year-old female patient with an abdominal paraaortic extra-adrenal pheochromocytoma (paraganglioma), presenting arterial hypertension. The predominant catecholamine produced by the tumor was norepinephrine (4110 pg/ml; normal < 450 pg/ml). 131I metaiodobenzylguanidine (131I-MIBG), computed tomography and magnetic resonance imaging allowed location and characterization of the tumor. Histologically the tumor (weight = 34.2 g; 5.8 x 4 x 3 cm) was a typical pheochromocytoma.

Multiple endocrine neoplasia type 2A. Study of a family

INTRODUCTION

Pheochromocytomas (Pheo) can occur sporadically, isolated or in association with other neuroendocrine lesions. In multiple endocrine neoplasia type 2A (MEN-2A), Pheo is associated to medullary thyroid carcinoma (MTC) or its precursor, C-cell hyperplasia (CCH) and parathyroid hyperplasia. Genetic screening provides early diagnosis and preventive treatment. In order to validate DNA analysis as a reliable method of early identification of gene carriers, we compared the results of genetic screening with clinical, biochemical, imaging and pathological findings in the members of an affected family.

POPULATION AND METHODS

The diagnosis of a bilateral necrotic Pheo in a female patient led to the study of a family with four generations, aged 3 to 78 years (mean = 30.3 yrs). The study included a clinical examination; basal and pentagastrin stimulated calcitonin values; urinary catecholamines and their metabolites; serum calcium and a genetic study (direct sequence of PCR products from genomic DNA isolated from leucocytes using specific primers in exon 11 of the RET protooncogene of chromosome 10). The radiologic study, gammagraphic study (131I-MIBG) and magnetic resonance study were performed in members with clinical suspicion of Pheo.

RESULTS

Seven out of nine patients had a mutation on codon 634 of exon 11 of RET (TGC-CGC), leading to cysteine arginine substitution in the codified protein; all gene carriers had biochemical markers of MTC/CCH and four of Pheo. The Pheo patients underwent adrenalectomy (bilateral in three) and all the gene carriers underwent prophylactic thyroidectomy. The pathologic findings were: MTC in four (metastasized in one); CCH in three and parathyroid hyperplasia in one.

CONCLUSIONS

Phenotypic penetration of RET mutation was 100% for MTC/CCH, but only 57% of the gene carriers had Pheo. Genetic screening allowed early prophylactic treatment in four out of seven patients; pathologic findings revealed several evolutionary stages of the disease. Patients not yet showing Pheo are under close clinical and laboratory surveillance.

Regional distribution of ionic currents and membrane voltage responses of type II hair cells in the vestibular neuroepithelium

Basolateral ionic currents and membrane voltage responses were studied in pigeon vestibular type II hair cells using a thin slice through either the semicircular canal (SCC) crista or utricular macular epithelium. Whole cell tight-seal patch-clamp recording techniques were used. Current-clamp and voltage-clamp studies were carried out on the same cell. One hundred ten cells were studied in the peripheral (Zone I) and central (Zone III) zones of the SCC crista, and 162 cells were studied in the striolar (S Zone) and extrastriolar (ES Zone) zones of the utricular macula. One of the major findings of this paper is that hair cells with fast activation kinetics of their outward currents are found primarily in one region of the SCC crista and utricular macula, whereas hair cells with slow activation kinetics are found in a different region. In Zone I of the crista, 95% of the cells have fast activation kinetics ("fast" cells) and in Zone III of the crista, 86% of the cells have slow activation kinetics ("slow" cells). In the utricular macula slice, 100% of the cells from the S Zone are slow cells, whereas 86% of the cells from the ES Zones are fast cells. Oscillation frequency (f) and quality factor (Q) of the damped oscillations of the membrane potential during extrinsic current injections were studied in hair cells in the different regions. The slow cells in Zone III and in the S Zone have a statistically significantly lower f, as a function of the amplitude of injected current, when compared with the fast cells in Zone I and the ES Zone. Although Q varied over a small range and was <2.6 for all cells tested, there was a statistically significant difference between Q for the membrane oscillations of the slow cells and fast cells in response to a range of current injections.

Artifactual voltage response recorded from hair cells with patch-clamp amplifiers

Patch-clamp amplifiers (PCAs) are commonly used to characterize voltage- and current-clamp responses in the same cell. However, the cell membrane voltage response can be severely distorted by PCAs working in the current-clamp mode. Here we compare the voltage response of pigeon semicircular canal hair cells in situ, recorded with two different PCAs, and with a classic microelectrode bridge amplifier (BA). We found that the voltage response of hair cells recorded with PCAs differed significantly from that recorded with the BA. The true hair cell membrane voltage response to positive current steps was characterized by a strongly damped oscillation, whose frequency and duration depended on hair cell location in the sensory crista ampullaris.

Electrical response properties of avian lagena type II hair cells: a model system for vestibular filtering

Data presented represent the first electrical recordings from avian lagena type II hair cells. The perforated-patch variant of the whole cell recording technique was used to investigate how the macroscopic currents shaped the voltage response of the hair cells. Voltage-clamp data separated cells into two broad classes on the basis of differences in activation rates, rates and degree of inactivation, and pharmacological sensitivity. Current-clamp recordings revealed low-quality membrane voltage oscillations (Qc < 1) during pulse current injections. Oscillation frequency correlated with activation rate of the macroscopic currents. The quality of membrane oscillations (Qc) varied linearly with frequency for cells with little inactivation. For cells with rapid inactivation, no relationship was found between Qc and frequency. Rapid inactivation may serve to extend the bandwidth of vestibular hair cells. The frequency measured from voltage responses to pulsed currents may reflect the corner frequency of the cell. The filtering properties of avian lagena hair cells are like those found in all other vestibular end organs, suggesting that the electrical membrane properties of these cells are not responsible for specializing them to a particular stimulus modality.

[The variability of the heart rate in the first 24 hours after fibrinolytic therapy in acute myocardial infarct]

AIM OF THE STUDY

The role of heart rate variability changes in the appraisal of reperfusion after fibrinolytic therapy in acute myocardial infarction is still controversial. The aim of this study was to analyze the influence of reperfusion and infarct site on heart rate variability within 24 hours after infarction.

PATIENTS AND METHODS

We studied 45 patients with a mean age = 56.3 +/- 12.4 years, 25 with anterior infarction and 20 with inferior infarction. The reperfusion was defined by the simultaneous presence of three classic noninvasive criteria (fast relief of pain, fast regression of ST segment elevation and early peak of CK). We studied heart rate variability parameters in time-domain and frequency-domain on a 24-hour Holter ECG started at the same time as fibrinolytic therapy.

RESULTS

Thirty-three patients showed reperfusion. We did not find significant differences in the several parameters of heart rate variability between patients with reperfusion and patients without reperfusion, but the patients with anterior wall infarction showed a significant reduction in SDNN in comparison with patients with inferior wall infarction (84 +/- 28 ms vs 102 +/- 30 ms; p = 0.05). pNN50 (5.3 +/- 7.2 ms vs 10.5 +/- 9.8 ms; p = 0.04), LF (618 +/- 591 ms2 vs 1374 +/- 1761 ms2; p = 0.05) and TP (1415 +/- 1199 ms2/Hz vs 3015 +/- 4243 ms2/Hz).

CONCLUSION

These data suggest a relationship between infarct severity and sympathetic activation and/or reduction of vagal modulation, but a potential beneficial effect of reperfusion on autonomic nervous system alterations was not evident in the first day of acute myocardial infarction.

Recovery of semicircular canal primary afferent activity in the pigeon after streptomycin ototoxicity

Recovery of semicircular canal primary afferent activity in the pigeon after streptomycin ototoxicity. J. Neurophysiol. 80: 3297-3311, 1998. The electrophysiological activity of horizontal semicircular canal primary afferents (HSCPA) was investigated in vivo in the barbiturate-anesthetized pigeon by means of extracellular single-fiber vestibular nerve action potential recordings. The spontaneous and driven discharges to pulse (step/trapezoid waveform, peak velocity = 120 degrees/s) and sum-of-sines (0.03, 0.09, 0.21, 0.39, 0.93, 1.83 Hz, peak velocity = 30 degrees/s for each frequency) rotations were measured both in normal control animals and a group of animals at 30, 40, 50, 60, 71, and 150 days postinjection sequence (PIS) of streptomycin sulfate. Prior to 30 days PIS, the activity in the nerve was not appropriately modulated during and after rotation. At 30 days PIS and thereafter, the responses resembled those observed in control animals but with systematic changes in parameters of fitted pulse responses and fitted Bode plots as days PIS increased. The return of parameters characterizing the neural dynamics of the semicircular canals were monotonic and could be best described by either linear or exponential functions. After 30 days PIS, the mechanical cupula-endolymph system, the function of which can be inferred from the cupula long time constant (tauL) following step velocity, did not change systematically (tauL = 6.92 +/- 3.96, 8.64 +/- 5.52, 8.35 +/- 4.21, 10.00 +/- 2.79, 9.05 +/- 3.67, 7.05 +/- 2.72; means +/- SD). However, the mean gain (G) of the HSCPA response to pulse rotation nearly doubled between 30 and 150 days PIS (from 1.31 +/- 0. 39 to 2.40 +/- 1.04) and returned linearly to control values (G = 2. 39 +/- 0.77) over this time period [G = 1.33 + 0.009(PIS-30), R2 = 0. 92, P < 0.05]. Meanwhile, neural adaptation as quantitated using a fractional operator, k, decayed exponentially (single exponential) to an asymptote. The time constant of this exponential was approximately 55 days [k = 0.034 + 0.33e-(PIS-30)/55.4, R2 = 0.99, P < 0.01]. Features of the spontaneous discharge previously shown to be correlated with k changed appropriately. That is, the coefficient of variation (CV) and frequency of firing (FF) decayed and grew asymptotically, respectively. These parameters also exhibited an exponential time course of return to control values from 30 to 150 days PIS [CV = 0.44 + 0.65e-(PIS-30)/21.5, R2 = 0.96, P < 0.01, and FF = 39.97 + 101.42(1 - e-(PIS-30)/32.6), R2 = 0.97, P < 0.01]. The trends of recovery for G, k, and tauL derived from analysis of the pulse response were confirmed by strong positive correlations with best fitted parameters obtained from analysis of the sum-of-sines frequency domain response of HSCPAs. There were statistically significant correlations (r = 0.90, P < 0.05 and r = 0.93, P < 0.05) between parameters (G, k) derived from pulse responses and those (G', k') from sum-of-sines responses, respectively. The cupula time constant based on sum-of-sines' data (tau'L) showed no statistically significant change between 30 and 150 days PIS (P > 0.05, analysis of variance). Thus the results in present study indicate that both the spontaneous discharge and the driven response to rotation of pigeon HSCPAs recovered their normal physiological status between 30 and 150 days PIS after hair cell death due to aminoglycoside ototoxicity. The recovery was systematic for the parameters chosen to be tested with the exception of the cupula long time constant, tauL. The mechanisms (changes in ciliary dynamics, changes in hair cell ionic currents, changes in bouton terminals, etc.) underlying these changes await further morphophysiological studies.

Neuronal plasticity: adaptation and readaptation to the environment of space

While there have been few documented permanent neurological changes resulting from space travel, there is a growing literature which suggests that neural plasticity sometimes occurs within peripheral and central vestibular pathways during and following spaceflight. This plasticity probably has adaptive value within the context of the space environment, but it can be maladaptive upon return to the terrestrial environment. Fortunately, the maladaptive responses resulting from neuronal plasticity diminish following return to earth. However, the literature suggests that the longer the space travel, the more difficult the readaptation. With the possibility of extended space voyages and extended stays on board the international space station, it seems worthwhile to review examples of plastic vestibular responses and changes in the underlying neural substrates. Studies and facilities needed for space station investigation of plastic changes in the neural substrates are suggested.