Effect of high-intensity resistance circuit-based training in hypoxia on aerobic performance and repeat sprint ability.

Recent acute studies have shown that high-intensity resistance circuit-based (HRC) training in hypoxia increases metabolic stress. However, no intervention studies have yet proven their effectiveness. This study aimed to analyze the effect of 8 weeks of HRC in hypoxia on aerobic performance, resting energy expenditure (REE), repeat sprint ability (RSA) and hematological variables. Twenty-eight subjects were assigned to hypoxia (FiO2  = 15%; HRChyp : n = 15; age: 24.6 ± 6.8 years; height: 177.4 ± 5.9 cm; weight: 74.9 ± 11.5 kg) and normoxia (FiO2  = 20.9%; HRCnorm : n = 13; age: 23.2 ± 5.2 years; height: 173.4 ± 6.2 cm; weight: 69.4 ± 7.4 kg) groups. Each training session consisted of two blocks of three exercises (Block 1: bench press, leg extension, front pull down; 2: deadlift, elbow flexion, ankle extension). Each exercise was performed at 6 repetitions maximum. Participants exercised twice weekly for 8 weeks and before and after the training program blood test, REE, RSA and treadmill running test were performed. Fatigue index in the RSA test was significantly decreased in the HRChyp (-0.9%; P < .01; ES = 2.75) but not in the HRCnorm . No changes were observed in REE and hematological variables. Absolute (4.5%; P = .014; ES = 0.42) and relative (5.2%; P = .008; ES = 0.43) maximal oxygen uptake (VO2 max), speed at VO2 max (4%; P = .010; ES = 0.25) and time to exhaustion (4.1%; P = .012; ES = 0.26) were significantly increased in HRChyp but not in the HRCnorm . No significant differences between groups were found. Compared with normoxic conditions, 8 weeks of HRC training under hypoxic conditions efficiently improves aerobic performance and RSA without changes in REE and red blood O2 -carrying capacity.

Comprehensive management of risk factors in peripheral vascular disease. Expert consensus.

INTRODUCTION: There is currently a degree of divergence among the main clinical practice guidelines on the management of risk factors for peripheral arterial disease (PAD). This project aims to gain understanding of the management of PAD risk factors in clinical practice and to reach a multidisciplinary consensus on the strategies to be followed in order to optimize its identification, treatment, and follow-up. METHODOLOGY: A multidisciplinary consensus following the Delphi methodology. RESULTS: Professionals (n = 130) with extensive experience in PAD participated in this consultation. The results suggest that in order to optimize the control of risk factors, efforts should be aimed at: (1) promoting the involvement and awareness of all specialists in the identification of and screening for the disease; (2) guaranteeing the possibility of evaluating the ankle-brachial index (ABI) in all the medical specialties involved; (3) promoting strategies for patients to quit smoking through the use of drugs, programs, or referrals to specialized units; (4) promoting an appropriate Mediterranean-based diet and the prescription of daily exercise; (5) raising awareness of the importance of ensuring LDL cholesterol values below 70 mg/dL, especially in symptomatic but also in asymptomatic patients (<55 mg/dL following the publication of the ESC/EAS guide); (6) recommending the use of antiplatelet therapy in asymptomatic patients with diabetes mellitus (DM) and/or a pathological ABI; and (7) protocolizing the annual evaluation of ABI in high-risk patients. CONCLUSION: This document presents the 22 agreed-upon strategies which are intended to help professionals optimize multidisciplinary management of PAD risk factors.

[Evaluation of the diagnostic test for rapid detection of covid-19 antigen (Panbio Covid rapid test) in primary care]. / Evaluación de la prueba diagnóstica de detección rápida de antígeno de covid-19 (Panbio Covid rapid test) en atención primaria.

OBJECTIVE: COVID-19 infection requires early diagnosis, with PCR being the gold standard test. The protocols advocate the use of rapid antigenic tests that require evaluation in actual clinical practice. The objective was to evaluate the diagnostic test for rapid antigen detection, Panbio Covid rapid test, compared with PCR, in patients with symptoms of 5 or less days of evolution and with a high-suspicion of infection by COVID-19 in a health center. MATERIALS AND METHODS: 103 patients over 14 years of age who attended an urban health center located in the Usera District of Madrid, with high-suspicion of COVID-19 infection, in the first 5 days of evolution from the onset of symptoms during the month of November 2020. INTERVENTIONS: diagnostic tests for COVID-19 are performed: antigen and PCR. RESULTS: The prevalence of the disease was 24.3% according to the PCR test and 17.5% according to the rapid antigenic test. The sensitivity was 72% (95% CI: 54.3-89.6%). The specificity was 100%. The positive and negative predictive values were 100% and 91.8% respectively. In the bivariate analysis, there was no relationship between symptoms and the presence of disease, except for myalgias (p=0.030). The multivariate analysis found a relationship between cough, dyspnea, fever, myalgia, anosmia/ageusia, and ocular symptoms and the presence of disease. CONCLUSIONS: The sensitivity and specificity for the Panbio rapid antigen test are similar to other studies performed in primary care. In high-prevalence of disease and with highly suspected symptoms, positive test results can be considered definitive, but negative results will require confirmation. Myalgia, fever, dyspnea, anosmia/ageusia, and ocular symptoms may be more related to the presence of COVID-19.

[Spine cord descompresion and instrumentation in a case of solid aneurysmal bone cyst in the lumbar spine]. / Descompresión medular e instrumentación en un caso de variante sólida de quiste óseo aneurismático en raquis lumbar.

We report a 8-year-old boy with two month history of pain and stiffness in his left lower extremity. On x-ray, MRI and scintigraphy examinations a lytic lesion affecting the body and posterior arc of his third lumbar vertebral become evident. The tumour was excised through a double, anterior and posterior approach; spinal fusion with posterior transpedicular instrumentation was also performed in the same procedure; in order to achieve solid fusion tricortical liofilized graft was also inserted. Histological studies evidenced finding compatible with aneurysmal bone cyst solid variant. Five years after surgery the patient is pain free and no recurrence is evident under diagnostic images tools. For the treatment of aneurysmal bone cyst of the spine we recommend complete excision of the tumour in a combined anterior and posterior one staged procedure, together with hardware instrumentation and bone graft, no recurrence or instability is seen after five years followup.

Modelization of anaerobic processes during co-digestion of slowly biodegradable substrates.

The influence of the soluble substrates over the anaerobic processes has been extensively investigated, but little is known about the effects of particulate substrate. The biodegradation of these substrates starts with the hydrolytic step, this process is slower than the other ones involved in the biodegradation of particulate substrates and usually becomes the rate-limiting step. This study investigate the effect of the initial total solids (TS) concentration on the anaerobic co-digestion of two slowly biodegradable organic substrates. The wastes mixtures were prepared at different dilutions in the range from 10% to 28% TS. From these experiments it was observed that as TS concentration increased, the methane production decreased. These results were modelled and it was observed that neither hydrolysis nor fermentation stages controlled the methane production rate. Being a substrate inhibition event experienced at the methanogenic stage the responsible of the lower methane production when operating at high TS concentrations.

[Descriptive study of hepatic steatosis and associated morbidity in Primary Care. (ESTEATOAP Study)]. / Estudio descriptivo de la esteatosis hepática y la morbilidad asociada en atención primaria. (Estudio ESTEATOAP).

OBJECTIVE: To study the recorded prevalence of hepatic steatosis in Primary Care, as well as the proportion of patients diagnosed with fatty liver diseases (FLD) including simple non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) versus steatosis by other causes. In addition, the proportion of cardiometabolic morbidities associated with NAFLD liver was studied. MATERIAL AND METHODS: A descriptive observational study was carried out on a population that included all patients with a recorded diagnosis of hepatic steatosis in an urban health centre that serves a population of 25,747 over the age of 14. A sample size of 229 patients was calculated. The demographic and clinical characteristics associated with hepatic steatosis are described. RESULTS: The prevalence of steatosis was 2.17% and 1.51% for NAFLD. The mean age was 62.42 years. The study included 114 (50.2%) women and 113 (49.8%) males. NAFLD was found in 147 (64.8%), and 64 (28.2%) were steatosis due to other causes. The proportion of patients with NAFLD and high transaminases was 24.13%, and the proportion of patients with NAFLD and GGT elevation was 18.6%. A high proportion of NAFLD had been found with cardiometabolic risk factors: 93.9% overweight and obesity, 55.1% diabetes, 54.4% hypertension, 32.9% metabolic syndrome, 35.2% hypertriglyceridaemia, and HDL risk 19.6%. A significant association was found between cardiometabolic risk factors and NAFLD in diabetes, obesity, and metabolic syndrome. DISCUSSION: Prevalence was only 1.51%, perhaps because of the low importance given to this disease. There is a high proportion of NAFLD with cardiometabolic risk factors and more in the general population. If all the causes of steatosis are considered there is a significant association between obesity, diabetes mellitus, and metabolic syndrome with NAFLD. CONCLUSIONS: The recorded prevalence of NAFLD is much lower than that of population studies, and a high presence of cardiometabolic factors has been found in these patients.

Landing differences between men and women in a maximal vertical jump aptitude test.

AIM: The aim of this study was to analyze the gender differences in the vertical ground reaction forces and the position of the center of gravity during the landing phase of a maximal vertical jump aptitude test. METHODS: The push-off, flight and landing phases of the jumps of 291 males (age = 19.6+/-2.8 years) and 92 females (age = 19.2+/-2.6 years), applicants to a Spanish faculty of sports sciences, were analyzed with a force platform. RESULTS: The greatest differences between men and women were found in the jump performance (women = 25.6+/-3.5 cm; men = 35.5+/-4.5 cm) and second peak vertical force value of the landing phase (women = 5.89+/-2.06 times body weight; men = 7.51 +/-2.38 times body weight), the values being greater in the men's group (P < 0.001). Correlation coefficients showed that the women utilized a different landing pattern than the one utilized by the men. CONCLUSION: Contrary to the authors' expectations, women showed lower second peak vertical force values during the landing. Taking into account only a kinetic point of view, they would have a lower risk of injury during the landing movement of maximal jumps. The lower values in the peak force, the delay of the impact of the calcaneus and the longer path of the center of gravity during the landing phase found in the women's group were related to a landing technique that is different from that of men.

Design and validation of a scale to assess preferences of type 2 diabetic patients towards different nutritional supplements.

OBJECTIVES: To design and validate a scale to evaluate preferences of type 2 diabetic patients towards nutritional supplements (Madrid scale) and to discover those taste attributes that are more discriminating. CONTEXT: ambulatory patients with type 2 diabetes mellitus. MATERIALS AND METHODS: 18 controls and 106 type 2 diabetic patients received 2 of the 7 stimuli studied (6 nutritional supplements and a differential salty stimulus) and then completed both scales and a criterion question. Two weeks later, 30 diabetic patients received a retest. The psychometric properties of the Madrid scale were studied and the relative importance of each stimuli attribute was assessed. RESULTS: Feasibility: The Madrid scale consists of 8 questions and is completed in less than five minutes; Dimensionality: A single dimension which explains 45.1% of the variance. Reliability: Cronbach's , 0.806; intraclass correlation coefficient, 0.835 (95% confidence interval: 0.653-0.922). Concurrent validity: Correlation indexes of the corrected total score with the criterion question and the Modified Wine-Tasting Scale, 0.731 (p < 0.0005) and 0.774 (p < 0.0005), respectively. The scale discriminated between subjects younger and older than 75 years and between supplements and the differential stimulus. Preferences: Glucerna SR chocolate, Glucerna SR strawberry, Glucerna SR vanilla, Diasip vanilla, Clinutren vanilla and Resource diabet vanilla. CONCLUSION: The Madrid scale has adequate psychometric properties for its use in research and daily clinical practice.

Manejo integral de los factores de riesgo en enfermedad arterial periférica. Consenso de expertos / Comprehensive management of risk factors in peripheral vascular disease. Expert consensus

Antecedentes y objetivo: Actualmente existe cierta divergencia entre las principales guías de práctica clínica sobre el manejo de los factores de riesgo de la enfermedad arterial periférica (EAP). El objetivo de este proyecto es conocer el manejo de los factores de riesgo de la EAP en la práctica clínica y alcanzar un consenso multidisciplinar sobre las estrategias que se tienen que seguir para optimizar su identificación, tratamiento y seguimiento. Metodología: Consenso multidisciplinar mediante metodología Delphi. Resultados: En la consulta participaron 130 profesionales con amplia experiencia en EAP. Los resultados sugieren que para optimizar el control de los factores de riesgo, los esfuerzos deben dirigirse a: 1) promover la involucramiento y concienciación de todas las especialidades en la identificación y el cribado de la enfermedad; 2) garantizar la posibilidad de realizar el índice tobillo-brazo (ITB) en todas las especialidades implicadas; 3) fomentar estrategias de deshabituación del tabaquismo mediante el uso de fármacos, programas o derivaciones a unidades especializadas; 4) promover el seguimiento de una alimentación adecuada basada en la dieta mediterránea y la prescripción de ejercicio diario; 5) concienciar sobre la importancia de alcanzar unos valores de colesterol unido a lipoproteínas de baja densidad (cLDL) inferiores a 70 mg/Dl, especialmente en pacientes sintomáticos, pero también en asintomáticos (< 55 mg/dL tras la publicación de la guía de la European Society of Cardiology y la European Atherosclerosis Society [ESC/EAS]); 6) recomendar el uso de antiagregantes plaquetarios en pacientes asintomáticos con diabetes mellitus (DM) y/o ITB patológico; y 7) protocolizar la reevaluación del ITB anualmente en pacientes de alto riesgo. Conclusión: Las 22 estrategias consensuadas en el presente documento pretenden ayudar a los profesionales a optimizar el manejo multidisciplinar de los factores de riesgo de la EAP (AU)

Introduction: There is currently a degree of divergence among the main clinical practice guidelines on the management of risk factors for peripheral arterial disease (PAD). This project aims to gain understanding of the management of PAD risk factors in clinical practice and to reach a multidisciplinary consensus on the strategies to be followed in order to optimize its identification, treatment, and follow-up. Methodology: A multidisciplinary consensus following the Delphi methodology. Results: Professionals (n = 130) with extensive experience in PAD participated in this consultation. The results suggest that in order to optimize the control of risk factors, efforts should be aimed at: (1) promoting the involvement and awareness of all specialists in the identification of and screening for the disease; (2) guaranteeing the possibility of evaluating the ankle-brachial index (ABI) in all the medical specialties involved; (3) promoting strategies for patients to quit smoking through the use of drugs, programs, or referrals to specialized units; (4) promoting an appropriate Mediterranean-based diet and the prescription of daily exercise; (5) raising awareness of the importance of ensuring LDL cholesterol values below 70 mg/dL, especially in symptomatic but also in asymptomatic patients (< 55 mg/dL following the publication of the ESC/EAS guide); (6) recommending the use of antiplatelet therapy in asymptomatic patients with diabetes mellitus (DM) and/or a pathological ABI; and (7) protocolizing the annual evaluation of ABI in high-risk patients. Conclusion:This document presents the 22 agreed-upon strategies which are intended to help professionals optimize multidisciplinary management of PAD risk factors (AU)

Effects of pork vs veal consumption on serum lipids in healthy subjects.

AIMS: To analyse the influence of lean pork (P) and veal (V) consumption on the lipid profile of healthy subjects within the framework of a healthy diet comprising low levels of total fat (TF), saturated fatty acids (SFA) and cholesterol. DESIGN: Double-crossover, randomized and controlled trial SUBJECTS: 44 healthy individuals (22 male and 22 female), recruited voluntarily from the University Complutense of Madrid. The weight and lipid profiles of these volunteers were normal and their dietary patterns were typical for people in our area. INTERVENTIONS: The study comprised 4 phases: stabilisation phase (5 weeks), the participants followed their normal diet; second phase (6 weeks), half of the subjects, were randomised to lean pork or veal consumption, 150 g per day, for their main meal of the day; washout period (5 weeks) and final phase, which was the second phase of intervention (6 weeks). During the intervention stages, only the main meal of the day was taken in the Hospital. The rest of the subjects' diets consisted of different fortnightly menus designed in accordance with the recommendations of the Spanish Society of Arteriosclerosis (SEA). RESULTS: After both stages of intervention had been completed, there was a mean reduction of 5.5% in low-density lipoprotein cholesterol. However, after each intervention there were no significant differences between those who had consumed P, 2.62 (0.55) mmol/L and those who had consumed V, 2.71 (0.47) mmol/L. No differences were observed in any of the other parameters between those who had consumed P and those who had consumed V. CONCLUSIONS: Lean pork and veal produces similar effects on the lipid profiles of healthy subjects. Its consumption, as part of the saturated fat and cholesterol-controlled diet, could therefore be included in food guidelines, both for normal and therapeutic diets.

Glycemic control and maternal and fetal outcomes in pregnant women with type 1 diabetes according to the type of basal insulin.

OBJECTIVE: To examine the potential role of the type of basal insulin on glycemic control and maternal and foetal outcomes in pregnant women with type 1 diabetes (T1DM). STUDY DESIGN: Retrospective cohort study of pregnancies attended at 18 Spanish tertiary hospitals. INCLUSION CRITERIA: T1DM, singleton pregnancies, delivery between 2002-2010, and use of the same basal and prandial insulin from before pregnancy until delivery. RESULTS: A total of 1534 pregnancies were included. The basal insulin most commonly used was Neutral Protamine Hagedorn (NPH) (51.7%), followed by glargine (23.2%) and continuous subcutaneous insulin infusion (CSII) (21.1%). CSII users had longer diabetes duration. Multiple logistic regression analysis showed that CSII was independently associated with lower doses of insulin, higher glycated haemoglobin (HbA1c) in all trimesters, and higher rates of miscarriage, preterm birth and neonatal hypoglycemia. Glargine was related to a higher risk of preterm birth and a small-for-gestational age infant (SGA). The odds ratios (OR) of the associations between insulin type and clinical outcomes (from 0.642 to 4.894) have a relevant magnitude. CONCLUSIONS: In this observational study of pregnant women with T1DM, the type of basal insulin was independently associated with metabolic variables and foetal outcomes.

Effects of droperidol and ondansetron on dispersion of ventricular repolarization: A randomized double-blind clinical study in anesthetized adult patients.

BACKGROUND AND OBJECTIVE: Droperidol and ondansetron prolong QT interval, a circumstance that has raised some concerns regarding the possibility of inducing torsades de pointes (TdP). However drug-induced spatial dispersion of ventricular repolarization has been shown to be the principal arrhythmogenic substrate for TdP. The aim of this study is to explore the effects of droperidol and ondansetron on the dispersion of repolarization, measured using the T peak-to-end interval (Tp-e) and Tp-e/QT and Tp-e/RR(1/2) ratios in surgical anesthetized patients. METHODS: A randomized, double-blind study carried out on sixty-three adult patients without cardiac disease or factors favoring QT prolongation and undergoing non-cardiac surgery were randomly assigned to the droperidol or ondansetron group. Under propofol anesthesia, a 12-lead EKG was obtained, and 1.25mg droperidol or 4mg ondansetron was injected. Five minutes later, a new 12-lead EKG was recorded. EKG analyses were independently performed by two cardiologists blinded to the state of the traces or group allocation. QT, RR and Tp-e intervals were measured by averaging five successive beats in leadII (QT) or V5 (Tp-e). The mean value for each measurement was calculated for statistical analysis. RESULTS: Thirty-two patients (19 women) received droperidol, and 31 (22 women) ondansetron. Droperidol and ondansetron prolonged the QTcF interval (Fridericia formula) by 6.8 and 7.2ms (mean values) respectively, but neither droperidol nor ondansetron increased the Tp-e interval or Tp-e/QT and Tp-e/RR(1/2) ratios. CONCLUSION: At antiemetic doses, neither ondansetron (4mg) nor droperidol (1.25mg) increases the dispersion of ventricular repolarization in healthy adult patients anesthetized with propofol.

Apoflavodoxin: structure, stability, and FMN binding.

Flavodoxins are one domain alpha/beta electron transfer proteins that participate in photosynthetic reactions. All flavodoxins carry a molecule of flavin mononucleotide (FMN), non-covalently bound, that confers redox properties to the protein. There are two structurally distinct flavodoxins, short ones and long flavodoxins; the latter contain an extra loop with unknown function. We have undertaken the study of the stability and folding of the apoflavodoxin from Anabaena (a long flavodoxin) and the analysis of the interaction between the apoflavodoxin and FMN. Our studies indicate that apoflavodoxin folds in a few seconds to a form that is competent in FMN binding. The stability of this apoflavodoxin is low and its urea denaturation can be described by a two-state mechanism. The role of the different parts of the apoflavodoxin in the stability and structure of the whole protein is being investigated using mutagenesis and specific cleavage to generate apoflavodoxin fragments. The X-ray structure of apoflavodoxin is very similar to that of its complex with FMN, the main difference being the conformation of the two aromatic residues that sandwich FMN in the complex. In apoflavodoxin these groups interact with each other so closing the FMN binding site. Despite this fact, apoflavodoxin binds FMN tightly and rapidly, and the resulting holoflavodoxin displays a high conformational stability. We have found that one role of the aromatic residues that interact with FMN is to help to retain bound the reduced form of the cofactor whose complex with apoflavodoxin is otherwise too weak.

Efficacy of low-dose OKT3 as cytolytic induction therapy in heart transplantation.

BACKGROUND: The need for prophylactic cytolytic treatment in heart transplantation is a controversial issue. Its use, however, might prevent the onset of cellular rejection in the immediate postoperative period, facilitating patient management. It has recently been suggested that the administration of these products at low doses might have the same immunologic impact and would reduce secondary effects and the cost of treatment. METHODS: In a nonrandomized retrospective study, we assessed 45 consecutive patients who underwent orthotopic heart transplantation in 1992 and 1993. Six patients who died before receiving the complete OKT3 dose were excluded. Twenty-three patients were treated with 5mg/day doses of OKT3 for 7 consecutive days. Another 16 patients received 2.5 mg of OKT3 for 7 consecutive days. RESULTS: There were no significant differences between the two groups with respect to CD3 counts on days 2 (0.1% +/- 0.3% versus 0.04% +/- 0.25%; p > 0.05) and 6 (0.2% +/- 0.45% versus 0.1% +/- 0.3%; p > 0.05), number of rejection episodes (1.45% +/- 0.8% per year of follow-up versus 1.7% +/- 1.2%, p = 0.66), number of infectious complications (8 versus 3, p > 0.05), total methylprednisolone dose used to treat rejection crises (3900 +/- 2765 versus 3600 +/- 1963 mg; p = 0.71), adverse effects attributed to OKT3 (two versus none), or length of the postoperative hospital stay (36.8 +/- 19 versus 30.2 +/- 20.9 days). CONCLUSIONS: As cytolytic induction therapy in heart transplantation, a daily regimen of 2.5 mg of OKT3 for 7 days achieves the same clinical and immunologic effect as the conventional 5 mg/day dose. In addition, it results in a considerable reduction in the cost of treatment.

Mitral valve replacement in a heart transplant recipient with iatrogenic mitral regurgitation.

A 65-year-old cardiac transplant recipient suffered rupture of the mitral valve apparatus during endomyocardial biopsy of the left ventricle. Severe mitral regurgitation resulted, and because of heart failure with progressive clinical deterioration the patient was finally subjected to mitral valve replacement. He had a favorable postoperative course and is now asymptomatic.

Several distinct receptor binding enkephalins in olivocochlear fibers and terminals in the organ of Corti.

Biochemical studies centering on the use of reverse-phase high-performance liquid chromatography (HPLC) and radioimmunoassays (RIA) demonstrate the presence in the guinea pig organ of Corti of at least 3 enkephalin-related peptides, two of which are identified as Met- and Leu-enkephalin, respectively. Enkephalins were identified and quantitated by HPLC-RIA in the isolated second turn of the organ of Corti, but were not found in stria vascularis or auditory nerve dissected from the cochlea. Three enkephalin-immunoreactive HPLC fractions inhibited the binding of labeled naloxone to rat brain membranes. All enkephalins identified by the combined HPLC-RIA procedure had an apparent molecular weight similar to that of Met- and leu-enkephalin peptide standards. Immunocytochemistry, performed with the best-characterized Met-enkephalin antiserum used in the RIAs, localized the enkephalin-like immunoreactivity to lateral efferent fibers and terminals under inner hair cells of the organ of Corti. Other antisera raised against Met-enkephalin, not used for RIA, visualized enkephalin-like immunoreactivity in medial efferent fibers under outer hair cells as well. This enkephalin-like immunoreactivity may reflect the presence in the medial efferent system of other structurally similar peptides in addition to those detected biochemically. Efferent fiber lesion, by evulsion of the vestibular nerve close to the vestibulocochlear anastomosis in which the olivocochlear fibers run, eliminated enkephalin-like immunoreactivity and the enkephalin-related peptides identified by HPLC-RIA.

Immunocytochemical localization of choline acetyltransferase-like immunoreactivity in the guinea pig cochlea.

The immunocytochemical localization of the enzyme choline acetyltransferase (ChAT) was examined in the guinea pig organ of Corti to determine if both lateral and medial systems of efferents would show immunoreactive labeling for this specific enzyme marker of cholinergic neurons. Cochleae were also examined after lesion of efferents to determine if ChAT-like immunoreactivity is confined to efferents. ChAT-like immunoreactivity was seen in the inner spiral bundle, tunnel spiral bundle and by the bases of inner hair cells corresponding to the lateral system of efferents. ChAT-like immunoreactivity was also seen in crossing fibers and puncta at the bases and by the nuclei of outer hair cells corresponding to the medial system of efferents. With the use of video enhanced contrast microscopy more than 9 ChAT-like immunoreactive puncta at the bases of outer hair cells could be resolved. In cochleae examined 6 weeks after ipsilateral lesion of efferents, no ChAT-like immunoreactivity was observed. These results add strong evidence that acetylcholine is a transmitter of both the medial and lateral systems of efferents.

Glutaminase-like immunoreactivity in the organ of Corti of guinea pig.

The distribution of glutaminase (GLNase)-like immunoreactivity (IR) in the normal and surgically de-efferented organ of Corti of guinea pig was studied. Primary antisera were against phosphate-dependent GLNase from rat kidney. Indirect immunocytochemical techniques were used; IR was visualized in cryostat sections through immunofluorescence, and through immunofluorescence or with horseradish peroxidase reaction product in surface preparations. Standard microscopy and video-enhanced light microscopy with asymmetric illumination contrast were used. GLNase-like IR was found at inner hair cells (IHCs) in the normal and in the de-efferented organ of Corti, in the tunnel spiral bundle, in tunnel-crossing fibers, in endings high up on outer hair cells (OHCs), in outer spiral bundles, in puncta close to OHCs, and in large, efferent endings at OHC bases. There was no GLNase-like IR at OHCs in the de-efferented organ of Corti. It is concluded that GLNase-like IR is present in auditory nerve dendrites at IHCs and in olivocochlear efferents of the medial system, and that future studies are needed to determine whether also the lateral system of olivocochlear efferents contains GLNase-like IR. A diagram is included depicting the relation between OHCs and efferent nerve endings along the cochlear spiral, showing that in the apicalmost 3/4 turn of the spiral OHCs have no efferent endings.

Proenkephalin and prodynorphin related neuropeptides in the cochlea.

Dynorphin B (rimorphin), a proenkephalin B (prodynorphin)-derived peptide, and met-enkephalin-Arg6, Gly7, Leu8 (met-enkephalin octapeptide), a proenkephalin A-derived peptide, were identified in the mammalian cochlea by specific radioimmunoassays. The antisera are directed against unique sequences in the peptides, and this immunoreactivity cannot be ascribed to cross-reaction with any other known opioid peptides. Met-enkephalin octapeptide and dynorphin B can for this reason serve as reliable markers for the proenkephalin A- and proenkephalin B-derived peptides, respectively. Lesion studies in the cochlea indicate that dynorphin B is confined to olivocochlear efferents. It has not been determined if the dynorphin-containing neurons are the same as those known to contain enkephalin-related peptides, or if they may be cholinergic. Different, presumably inhibitory, neurotransmitters or modulators in the olivocochlear fibers create the possibility of separately modulating the effects of inner or outer hair cells on auditory nerve activity, and so becoming able to study their individual actions in audition. The olivocochlear fiber-hair cell-eighth nerve interaction may provide a valuable model for a complex multi-transmitter synaptic junction.