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Biomedical subjects

B Herreros

Publications and source records attributed to B Herreros.

At least 19 recordsLinked to original sources
PubMed2006

Oesophageal motility disorders in type 1 diabetes mellitus and their relation to cardiovascular autonomic neuropathy.

The relationship between cardiovascular autonomic neuropathy (CVAN) and oesophageal dysfunction in diabetes mellitus has not been well established because reports are contradictory. The aim of this study was to assess oesophageal function and its correlation with CVAN in type 1 diabetic patients without oesophageal symptoms. Forty-six type 1 diabetic patients without oesophageal symptoms (DG) and 34 healthy volunteers (CG) were studied. Both groups underwent CVAN tests and oesophageal manometry and pH-metry. Differences between groups regarding results of cardiovascular autonomic tests and oesophageal studies were statistically analysed. Compared with the CG, the DG group showed insufficient lower oesophageal sphincter (LOS) relaxation and a higher percentage of simultaneous waves (P < 0.01). Patients with CVAN (n = 22) showed a higher prevalence of pathological simultaneous contractions (>10%), and the prevalence of simultaneous waves related to the degree of autonomic neuropathy was: 9% of patients without CVAN, 7% of those suspected to have it and 50% of patients with CVAN (P < 0.001). Factors associated with the presence of pathological simultaneous waves (>10%) were the presence of CVAN and duration of diabetes (P < 0.05, logistic regression analysis). Increase in simultaneous waves and impaired relaxation of LOS are more frequent in diabetic patients with CVAN.

Adult↗
PubMed2005

Prevalence of silent fecal and urinary incontinence in women from the town of Teruel.

OBJECTIVES: To study the prevalence of fecal (FI) and urinary incontinence (UI) in women from Teruel (Spain), as well as the clinical conditions associated with these disorders. METHODS: We studied prospectively women with an age range of 20-64 years who were randomly selected from the population seen in a primary care center because of medical disorders not related to incontinence. Patients with functional or cognitive impairment were excluded. Medical and obstetric antecedents, as well as the type and frequency of incontinence symptoms were collected in a questionnaire. RESULTS: Out of 115 women, 103 completed the study (mean age: 41+/-12 years range 20-64). UI was present in 34.9% (stress 33%, urge 14%, mixed 47%), FI in 14 (13.6%) (flatus 57%, liquid stools 43%), and 10 (9.7%) displayed both disorders. Age > 42 years and body mass index more or equal of 25 were associated with FI and UI; pregnancy was only associated with UI, but the group of women with more or equal of 2 vaginal deliveries showed a higher frequency of FI (p < 0.05, Chi squared test). In the multivariate analysis, only the presence of UI was associated with FI (OR 6.0; CI 95% 1.7-21). Association of FI and UI was more frequent in women older than 42 years (OR 16.7, CI 95% 1.9-141). No statistical differences were found when smoking, exercise, and type of childbirth were compared between the presence/absence of FI or UI. CONCLUSIONS: Urinary and fecal incontinence are frequent in women, and the coexistence of both disorders is not uncommon. Age, overweight and parity are associated with the presence of fecal and/or urinary incontinence.

Adult↗
PubMed2004

Unstimulated salivary flow rate, pH and buffer capacity of saliva in healthy volunteers.

OBJECTIVES: To assess the salivary flow rate, pH, and buffer capacity of healthy volunteers, and their relationships with age, gender, obesity, smoking, and alcohol consumption, and to establish the lower-end value of normal salivary flow (oligosialia). METHODS: A prospective study was conducted in 159 healthy volunteers (age > 18 years, absence of medical conditions that could decrease salivary flow). Unstimulated whole saliva was collected during ten minutes, and salivary flow rate (ml/min), pH, and bicarbonate concentration (mmol/l) were measured using a Radiometer ABL 520. The 5 percentile of salivary flow rate and bicarbonate concentration was considered the lower limit of normality. RESULTS: Median salivary flow rate was 0.48 ml/min (range: 0.1-2 ml/min). Age younger than 44 years was associated with higher flow rates (OR 2.10). Compared with women, men presented a higher flow rate (OR 3.19) and buffer capacity (OR 2.81). Bicarbonate concentration correlated with salivary flow rate. The lower-end values of normal flow rate and bicarbonate concentration were 0.15 ml/min and 1.800 mmol/l, respectively. The presence of obesity, smoking, and alcohol consumption did not influence salivary parameters. CONCLUSIONS: In healthy volunteers, salivary flow rate depends on age and gender, and correlates with buffer capacity. Obesity, smoking, and alcohol use do not influence salivary secretion.

Adolescent↗
PubMed2003

Dental and periodontal lesions in patients with gastro-oesophageal reflux disease.

OBJECTIVE: Dental erosion has been considered an extraesophageal manifestation of gastro-oesophageal reflux disease, but few reports have studied the relationship between this disease and other periodontal or dental lesions. The aim of this study was to investigate the prevalence of dental and periodontal lesions in patients with gastro-oesophageal reflux disease. PATIENTS AND METHODS: A total of 253 subjects were prospectively studied between April 1998 and May 2000. Two study groups were established: 181 patients with gastro-oesophageal reflux disease and 72 healthy volunteers. Clinical assessment, including body mass index and consumption of tobacco and alcohol, was performed in all subjects, as well as a dental and periodontal examination performed by a dentist physician, blind as to the diagnosis of subjects. Parameters evaluated were: (a) presence and number of dental erosion, location and severity, according to the Eccles and Jenkins index [Prosthet Dent 1979;42:649-53], modified by Hattab [Int J Prosthes 2000;13:101-71; (b) assessment of dental condition by means of the CAO index; and (c) periodontal status analysed by the plaque index, the haemorrhage index, and gingival recessions. RESULTS: Clinical parameters were similar in both groups (p > 0.05). Age was statistically associated with the CAO index, presence of dental erosion, and gingival recession (p < 0.001, Student's t-test). Compared with the control group, the percentage of dental erosion was significantly higher in the gastro-oesophageal reflux disease group (12.5 vs. 47.5%, p < 0.001, chi2-test), as was the number and severity of dental erosions (p < 0.001, Student's t-test). Location of dental erosion was significantly different between groups. Age was not statistically related to either the amount or severity of dental erosion. CAO and periodontal indices were similarly distributed between groups. CONCLUSIONS: Dental erosion may even be considered as an extraesophageal manifestation of gastro-oesophageal reflux disease. The fact that the prevalence of caries and periodontal lesions is similar in patients with gastro-oesophageal reflux disease and in healthy volunteers suggests a lack of relationship with gastro-oesophageal reflux disease.

Adolescent↗
PubMed2000

[Prospective and comparative study of pacemaker implants carried out at the electrophysiology laboratory and the operating room].

INTRODUCTION AND OBJECTIVES: Permanent pacemaker implantation is done by different physicians with either a surgical or clinical training. Our objective was to evaluate if there were significant differences in the implantation parameters and in the complication rate among implantations performed by cardiologists in the electrophysiologic laboratory and cardiological surgeons in the operating room. MATERIAL AND METHODS: We prospectively collected those patients' data who received a first pacemaker implantation by cardiovascular surgeons and electrophysiologists during the year 1998. Data collected included demographic information, indication for pacing, surgical time, complications during procedure, stimulation and sensing thresholds as well as type of pacing. RESULTS: We first-implanted 216 pacemakers in a one year period, 101 by cardiovascular surgeons and 115 by electrophysiologists. 56% were male patients. Average age in the surgery group was 74.2 +/- 9 years and 72.09 +/- 12 in the electrophysiology group (p = NS). Main diagnoses were as follows: complete heart block in 32.9% patients, complete heart block 2. degrees 16.4%, sinus node dysfunction 12.2%, AV node ablation 12.2% and others. The complications rate for surgery group was 4% and 1.7% for electrophysiologists (p = NS). Electrophysiologists placed more bicameral devices. No clinically significant differences were found among other implant parameters. CONCLUSIONS: Pacemaker implant by cardiologists in an electrophysiologists laboratory is a safe procedure that does not have more complications when compared to the same procedure done in the operating room by surgeons. This allows hospital resource optimization and reduction of hospital stay length.

Aged↗
PubMed2000

Moment analysis as a systematic tool for NMR powder pattern analysis.

The low order moments for chemical shift and second-order quadrupolar powder patterns have been calculated as functions of the anisotropy and asymmetry parameter of the governing interaction, and the expressions inverted to give these parameters as a function of the moments. Theoretical simulations and experimental experience show that moment analysis in most cases equals and in some cases exceeds the accuracy of direct inspection as a method of obtaining NMR parameters. We illustrate the efficacy of the method applied to 31P chemical shift spectra of nucleic acids, and 39K second-order patterns of series of potassium salts.

Adenosine Monophosphate↗
PubMed1999

[Analysis of local electrograms and characteristics of the ablation procedure in left-sided accessory pathways that required five or more pulses of radiofrequency].

INTRODUCTION AND OBJECTIVES: Radiofrequency ablation of left sided accessory pathways requires multiple pulses in some patients due to different factors such as inadequate mapping, inappropriate tissue electrode contact and particular anatomic factors. However these characteristics have not been specifically analyzed. METHODS: We have studied a prospective ablative series of 65 consecutive patients with left-sided pathways submitted to radiofrequency ablation by a simplified technique. In every application point, we analyzed the electrogram features, application point, impedance, potency and temperature. RESULTS: 52 patients (80%) required less than 5 radiofrequency pulses (group A) and 13 (20%) required > or = than 5 pulses (group B). The presence of a suggestive potential accessory pathway in local electrogram was similar in both groups and there were no differences in the local A-V or V-A intervals. However, in patients with pre-excitation the Delta-V interval was shorter in group A than in group B (8 ms vs 15 ms; p < 0.001). Furthermore, the impedance observed from the ablation point in group A was lower (108 +/- 12 vs 121 +/- 22 ohms; p < 0.001), and the maximum watts required to reach the predetermined temperature was higher in group A (42 +/- 16 vs 31 +/- 18 watts; p < 0.001). Final success of the procedure was 100%. CONCLUSIONS: Patients requiring more than 5 radiofrequency pulses had electrograms and tissue contact equal or better than those requiring less than 5 pulses. This suggests that difficulties encountered in some procedures can be due to anatomical factors rather than inaccurate mapping or insufficient tissue contact.

Adolescent↗
PubMed1996

[Prevalence of drinkers at risk and associated factors among men attending primary care clinics].

OBJECTIVES: To quantify the prevalence of risk drinkers among men seeking health care, establish consumption patterns and relate them to socio-demographic features and health habits. DESIGN: Crossover study. First phase of an experimental study. SETTING: Four primary care teams in Area 10, Madrid. PATIENTS: Males between 18 and 65 who attended for on-demand medical care. A systematic sample was selected (n = 562). MEASUREMENTS: A questionnaire collecting socio-demographic characteristics, health habits and alcohol consumption (frequency, consumption pattern, intake of Weekly Units of alcohol (WU) and alcohol-related problems). 94.2% replied. 38% were habitual drinkers (drink four or more days a week), while 18.9% were week-end drinkers. Prevalence of drinkers consuming over 21 WU was 24.8%; and over 35 WU, 16.2%. Whether the cut-off point was fixed at 21 or 35 WU. The alcohol taken was related to educational level, physical exercise, smoking and taking other drugs. On average, single people, smokers, other drug-consumers, ex-drinkers and habitual drinkers were those who displayed most problems connected with alcohol consumption. CONCLUSIONS: There is a similar profile of health habits for the groups consuming over 21 WU and 35 WU, which should make preventive care pay attention to both groups of drinkers.

Adolescent↗
PubMed1995

Vascular and hormonal responses to arginine: provision of substrate for nitric oxide or non-specific effect?

1. The vascular and hormonal effects of L- and D-arginine were compared in healthy subjects and in patients with insulin-dependent diabetes mellitus or untreated essential hypertension. 2. Infusion of L- or D-arginine (40 mumol/l) in the forearm vascular bed, sufficient to increase the local concentration approximately 20-fold, had no effect on blood flow or the vasodilator response to acetylcholine (30 and 100 nmol/min) in patients with insulin-dependent diabetes (n = 7) or essential hypertension (n = 7), or in age- and sex-matched control subjects (n = 7 in both groups). 3. Systemic infusion of 10 g of L-arginine (n = 5) or D-arginine (n = 3) increased plasma concentration of arginine approximately 20-fold without altering supine or erect haemodynamics. Increases in plasma insulin, prolactin and glucagon were seen with both enantiomers. The stereopurity of arginine was confirmed in a cell-culture assay system. 4. We conclude that, in healthy subjects and patients with essential hypertension or insulin-dependent diabetes, synthesis of nitric oxide within the vasculature is not limited by substrate availability. At high concentrations of arginine, non-stereospecific effects, including alterations in hormone concentration, occur. It remains to be determined whether these non-stereospecific hormonal changes might contribute to certain haemodynamic effects of arginine.

Adult↗
PubMed1994

Participation of Na+ channels in the response of carotid body chemoreceptor cells to hypoxia.

The role played by Na+ channels of carotid body (CB) chemoreceptor cells was investigated by studying the effects of tetrodotoxin (TTX) on the release of 3H-labeled catecholamines ([3H]CA) by adult rabbit CBs previously incubated with the precursor [3H]tyrosine. TTX inhibited partially the release of [3H]CA elicited by mild hypoxia (10 or 7% O2) or by depolarizing incubation medium containing 20 or 30 mM KCl, but the response to more intense hypoxia (5 or 2% O2) or to higher KCl concentration (40 or 50 mM) was not significantly affected. The release of [3H]CA elicited by acidic stimuli, either 20% CO2 (pH 6.6) or the protonophore dinitrophenol (100 microM), although comparable in magnitude to that elicited by mild hypoxia, was not modified by TTX. These results provide evidence for the first time that Na+ channels of chemoreceptor cells participate in the transduction of hypoxic stimuli into the neurotransmitter release response of these cells and suggest that Na+ current operates as an amplifying device that enhances the initial cell depolarization mediated by the closure of the O2-sensitive K+ channels. Sympathetic denervation of CBs was followed by a marked reduction in the release of [3H]CA elicited by veratridine or by 20 mM KCl, suggesting that the number of Na+ channels in chemoreceptor cells decreases after denervation.

Acids↗
PubMed1992

Characterization of cultured chemoreceptor cells dissociated from adult rabbit carotid body.

Short-term cell cultures were obtained from enzymatically dissociated carotid bodies from adult rabbits, and morphological and functional characterization of the cultured chemoreceptor cells were carried out. Under phase contrast, freshly isolated type I cells are round, bright, and 10-14 microns in diameter and exhibit strong fluorescence when stained with the glyoxylic acid technique. The content of endogenous dopamine in the cultures increased from 80 pmol/10(5) cells 2 h after plating the cells to 200 pmol/10(5) cells on the 3rd day, and the rate of synthesis and storage of [3H]dopamine from the precursor [3H]tyrosine increased from 1.7 pmol.10(5) cells-1.h-1 in 1-day cultures to 4 pmol.10(5) cells-1.h-1 on the 3rd day; the later values represent 80-85% of the expected values for the intact carotid body. After labeling with [3H]tyrosine, cultured chemoreceptor cells release [3H]dopamine when challenged by hypoxia, high external K+, or the protonophore dinitrophenol, the pattern of response being similar to that of the intact carotid body. When studied by whole cell clamp recording, individual chemoreceptor cells exhibit a marked variability in the properties of some ionic currents; the data, however, do not support the existence of distinct subpopulations of type I cells.

Animals↗
PubMed1991

Ionic mechanisms for the transduction of acidic stimuli in rabbit carotid body glomus cells.

1. The release of [3H]dopamine (DA) in response to inhibition of the Na+ pump or to intracellular acid load was studied in rabbit carotid bodies (CB) previously incubated with the precursor [3H]tyrosine. The ionic requirements of the release response and the involvement of specific ion transport systems were investigated. 2. Inhibition of the Na+ pump, by incubating the CB with ouabain or in K(+)-free medium, evokes a DA release response which requires the presence of Na+ and Ca2+ in the medium and is insensitive to nisoldipine. This suggests that the response is triggered by entry of external Ca2+ through Na(+)-Ca2+ exchange, a consequence of the increase in intracellular Na+ resulting from inhibition of the pump. 3. Incubation of the CB in medium equilibrated with 20% CO2 at pH 6.6, or in medium containing the protonophore dinitrophenol (DNP) or the weak acid propionate, elicits a DA release response which requires also the presence of Na+ and Ca2+ in the medium and is insensitive to dihydropyridines. 4. Ethylisopropylamiloride (EIPA), an inhibitor of the Na(+)-H+ exchanger, markedly decreases the release response elicited by DNP or propionate in bicarbonate-free medium, but has not any effect in bicarbonate-buffered medium. In the latter condition, the EIPA-insensitive release of DA is inhibited by reducing the HCO3- concentration in the medium to 2 mM or by removal of Cl-, suggesting that in bicarbonate-buffered medium a Na(+)-dependent HCO3(-)-Cl- exchanger is involved in the release response. 5. It is concluded that the release of DA by the chemoreceptor cells in response to acidic stimulation is triggered by entry of external Ca2+ through Na(+)-Ca2+ exchange. This exchange is promoted by the increase of intracellular Na+ that results from the operation of Na(+)-coupled H(+)-extruding mechanisms activated by the acid load.

Acids↗
PubMed1989

Leupeptin does not affect the normal signal transduction mechanism in platelets.

Calpains are Ca2+-dependent serine proteases that can regulate protein kinase C-mediated cellular events by cleaving the membrane-bound native enzyme to yield an activated cytosolic fragment. Inhibition of calpain by leupeptin may cause enhancement or inhibition of cellular functions depending on the nature of the protein kinase C reaction involved. We have studied the effects of leupeptin on platelet responses (aggregation, secretion, thromboxane B2 formation and intracellular Ca2+ and pH changes) induced by either thrombin, collagen or phorbol 12-myristate 13-acetate (TPA), which are known to activate protein kinase C by different mechanisms. Only thrombin-induced responses were inhibited by leupeptin. This suggests that the inhibitory effect of leupeptin is not due to antagonism of calpain in this system, but to direct interference with the proteolytic effect of thrombin.

Adenosine Triphosphate↗
PubMed1988

Activation of the release of dopamine in the carotid body by veratridine. Evidence for the presence of voltage-dependent Na+ channels in type I cells.

Veratridine (50 microM), an agent known to activate voltage-dependent Na+ channels, induced a strong release of [3H]dopamine from the rabbit carotid body in vitro. The effect of veratridine was dependent on the presence of both Na+ and Ca2+ in the extracellular medium and was abolished by 1 microM tetrodotoxin. These results suggest that chemoreceptor type I cells have voltage-dependent Na+ channels, which could be involved in the depolarization of the cell membrane and activation of voltage-dependent Ca2+ channels.

Animals↗
PubMed1988

All or none cell responses of Ca2+-dependent K channels elicited by calcium or lead in human red cells can be explained by heterogeneity of agonist distribution.

We have studied the all or none cell response of Ca2+-dependent K+ channels to added Ca in human red cells depleted of ATP by incubation with iodoacetate and inosine. A procedure was used which allows separation and differential analysis of responding and nonresponding cells. Responding (H for heavy) cells incubated in medium containing 5 mM K lose KCl and water and increase their density to the point of sinking on diethylphthalate (specific gravity = 1.12) on centrifugation. Nonresponding (L for light) cells do not lose KCl at all. There is no intermediate behavior. Increasing the Ca concentration in the medium increases the fraction of cells which become H. No differences in the sensitivity to Ca2+ of the individual K+ channels were detected in inside-out vesicles prepared either from H or from L cells. The Ca content of H cells was higher than that of L cells. Cells depleted of ATP by incubation with iodoacetate and inosine sustain pump-leak Ca fluxes of about 15 mumol/liter cells per hour. ATP seems to be resynthesized in these cells at the expense of cell 2,3-diphosphoglycerate stores at a rate of about 150 mumol/liter cells per hour. Inhibition of 2,3-diphosphoglycerate phosphatase by tetrathionate increased 6-8 times the measured rate of uptake of external 45Ca. This was accompanied by an increase in the fraction of H cells. All or none cell responses of Ca2+-dependent K channels have also been evidenced in intact human red cells on addition of Pb. They have the same characteristics as those in responding and nonresponding cells. The detailed study of the kinetics of Pb-induced shrinkage of red cells suspended in medium containing 5 mM K showed that changes of Pb concentration changed not only the fraction of H cells but also the rate of shrinkage of responding cells. H cells generated by Pb treatment contained significantly more lead than L cells. The above results suggest that the two all or none cell responses studied here can be explained by heterogeneity of agonist distribution among cells. Since pump-leak fluxes exist in both cases, differences of agonist distribution could be generated by heterogeneity of pumping among cells. This interpretation turns interest from K channels to Ca pumps to explain the heterogeneous behavior of red cells in response to a uniform stimulus.

Adenosine Triphosphate↗
PubMed1986

The role of calmodulin on Ca2+ -dependent K+ transport regulation in the human red cell.

Several lipophilic calmodulin antagonists (phenotiazines, butyrophenones and diphenylbutylpiperidines) inhibited Ca2+-induced loss of KC1 from human red cells. However, the Ki values for this effect did not bear good correlation with the Ki values reported for well-known calmodulin-dependent systems. In addition, the inhibition was strongly dependent on the haematocrit and valinomycin-induced KC1 fluxes were also affected. Added calmodulin did not have any effect on Ca2+-dependent 86Rb uptake by inside-out vesicles derived from red cell membranes whereas stimulation of Ca2+-dependent ATPase was apparent. Lipophilic anticalmodulins at high doses had all kinds of effects on 86Rb uptake by inside-out vesicles: increase, decrease or no change of the fraction of activated vesicles reached at submaximal Ca2+ concentrations, with or without modification of the relative rate of 86Rb uptake. The hydrophylic compound 48/80 decreased the fraction of activated vesicles reached at submaximal Ca2+ concentrations without affecting the relative rate of 86Rb uptake, but this effect took place only at concentrations 10-fold higher than the reported Ki for calmodulin-dependent systems. These results suggest that Ca2+-dependent K+ channels of red cells are not regulated by calmodulin.

Biological Transport↗