Contributions of dipolar relaxation processes and ionic transport to the response of liquids to electrical perturbation fields.

The objective of this work was to study the influence of small variations in the chemical structure on the molecular dynamics of liquids using as models bis(cyclohexylmethyl) 2-methyl- and dicyclohexyl 2-methylsuccinate. The dielectric behavior of the low molecular weight liquids was studied over a wide range of frequencies and temperatures. The results show that the temperature dependence of the dielectric strengths, relaxation times, and shape parameters of the secondary and glass-liquid relaxations are very sensitive to the slight differences in the structures of the liquids. Significant changes take place in the dielectric strength of the ß relaxation in the glass liquid transition. Moreover, the temperature dependence of the ß relaxation exhibits Arrhenius behavior in the glassy state and departs from this behavior in the liquid state. Special attention is paid to the temperature dependence of low-frequency relaxations produced by the motion of a macrodipole arising from charges located near the liquid-electrode boundaries.

[Study of presynaptic nigrostriatal pathway by 123-I-FD-CIT-SPECT (DatSCAN SPECT) in primary orthostatic tremor]. / Estudio de la vía nigroestriada presináptica mediante 123-I-FP-CIT-SPECT (DatSCAN SPECT) en el temblor ortostático primario.

INTRODUCTION: Primary orthostatic tremor (OT) is defined as a clinical syndrome with high frequency (13-18 Hz) tremor when standing predominantly involving legs and trunk. OT is thought to be driven by an unique supraspinal tremor generator. Previous studies suggest that the nigrostriatal dopaminergic transmission is impaired in patients with OT. CLINICAL CASE: All three patients at an age of 56, 45 and 72 years fulfilled the diagnosis criteria of primary OT. The duration of illness amounted to 4, 3 and 1 year, respectively. The three patients had single-photon emission computed tomography (SPECT) using 123-I-FP-CIT as dopamine transporter tracer (DatSCAN). RESULTS: DatSCAN was normal in every patient. CONCLUSIONS: OT is considered to be caused by a central oscillator because high-frequency tremor bursts are time locked in arm, leg, trunk, and even facial muscles and peripheral stimulation does not reset the tremor. Some reports suggest that the central generator may be located in the posterior fossa. In our patients presynaptic nigrostriatal pathway was normal.

Estudio de la vía nigroestriada presináptica mediante 123-I-FP-CIT-SPECT (DatSCAN SPECT) en el temblor ortostático primario / Study of presynaptic nigrostriatal pathway by 123-I-FD-CIT-SPECT (DatSCAN SPECT)

Introducción. El temblor ortostático primario (TOP) es una entidad clínica caracterizada por temblor en las extremidades inferiores y tronco, a una frecuencia entre 13-18 Hz, que aparece durante la bipedestación. Parece clara la participación de un oscilador a nivel central. Recientemente se ha apuntado el compromiso de la vía dopaminérgica nigroestriada como parte de la fisiopatología del TOP. Caso clínico. Los tres pacientes estudiados, con una edad de 56, 45 Y 72 años, cumplían criterios clínicos de TOP. El tiempo de evolución de los síntomas era de 4, 3 Y 1 año, respectivamente. A todos los pacientes se les realizó un 123-I-FP-CIT -SPECT (DatSCAN SPECT) marcando, por tanto, la proteína transportadora de dopamina a nivel presináptico para investigar el sistema dopaminérgico a ese nivel. Resultados. El estudio fue normal en todos los casos. Discusión. El TOP se considera debido a un oscilador central al descargar de forma síncrona los músculos de extremidades superiores, inferiores, tronco e incluso músculos faciales y no modificarse el temblor con estímulos periféricoso Diversos estudios sugieren la localización de este oscilador central a nivel de fosa posterior. En nuestros pacientes el estudio de la vía nigroestriada presináptica fue normal

Introduction. Primary orthostatic tremor (OT) is defined as a clinical syndrome with high frequency (13-18 HZ) tremor when standing predominantly involving legs and trunk. OT is thought to be driven by an unique supraspinal tremor generator. Previous studies suggest that the nigrostriatal dopaminergic transmission is impaired in patients with OT. Clinical case. All three patients at an age of 56, 45 and 72 years fulfilled the diagnosis criteria of primary OT. The duration of illness amounted to 4, 3 and 1 year, respectively. The three patients had single-photon emission computed tomography (SPECT) using 123-I-FP-CIT as dopamine transporter tracer (DatSCAN) Results. DatSCAN was normal in every patient. Conclusions. OT is considered to be caused by a central oscillator because high-frequency tremor bursts are time locked in arm, leg, trunk, and even facial muscles and peripheral stimulation does not reset the tremor. Some reports suggest that the central generator may be located in the posterior fossa. In our patients presynaptic nigrostriatal pathway was normal

Poly(tetrahydropyranyl-2-methyl methacrylate): comparative study in solution and at the air/water interface.

In this work a comparative study of different molecular-weight fractions of the amphiphilic polymer poly(tetrahydropyranyl-2-methyl methacrylate) (PTHPMM) in solution and at the air/water interface is reported. The synthesis of the polymer was carried out in solution by radical polymerization. The polymer was fractionated and five fractions were studied in solution and at the air/water interface. The weight-average molecular weight M(w), the second virial coefficient A(2), and the radius of gyration R(g) were determined in toluene by static light scattering. Intrinsic viscosities [eta] of the polymer fractions in three solvents were obtained. The Kuhn-Mark-Houwink-Sakurada relationships were established. The Langmuir isotherms for different polymer fractions were obtained at the air/water interface by monolayer compression at constant temperature. The overlap surface concentrations were determined, and from these results the radius of gyration in two dimensions was calculated. The thermodynamic power of the toluene and the air/water interface for PTHPMM were estimated from the empirical relationship between the radius of gyration in two and three dimensions and the weight-average molecular weight.

Reacción distónica aguda a neurolépticos atípicos y otros fármacos no neurolépticos / Acute dystonic reaction to atypical neuroleptics and other non-neuroleptics medications

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Adsorption Behavior of Amphiphilic Polymers.

The work reported here involves a study of the adsorption behavior of some amphiphilic polymers containing alternating copolymers of stearyl methacrylate, mono-n-octylitaconate, styrene, and 1-octadecene with maleic anhydride. We have employed chromatographic and thermogravimetric measurements in order to characterize the adsorption process. Silica gel was the stationary phase in the case of the polar column, and a mixture of THF/toluene or chloroform/toluene as the mobile phase. Toluene content in the mobile phase affects the capacity to desorb the polymer from the interface. The adsorption of the polymers onto silica substrates from toluene between other solvents has been measured also with static experiments. The results are discussed in terms of the incorporation of hydrophilic groups as maleic-anhydride or hydrophobic groups as stearyl and n-octyl chains. The solvent effect was also considered. Comparison of the adsorption isotherms for PA-18 onto hydrophilic substrate (Aerosil 200) from two different solvents shows strong competition of THF with the surface functionality of the substrate by the PA-18. Copyright 1999 Academic Press.

Detection of colonic cells in peripheral blood of colorectal cancer patients by means of reverse transcriptase and polymerase chain reaction.

Circulating tumour cells play a central role in the metastatic process, but little is known about the relationship between this cellular subpopulation and the development of secondary disease. This study was aimed at assessing the presence of colonic cells in peripheral blood of patients with colorectal cancer in different evolutionary stages, by means of reverse transcriptase polymerase chain reaction (RT-PCR) targeted to carcinoembryonic antigen (CEA) mRNA. In vitro sensitivity was established in a recovery experiment by preparing serial colorectal cancer cell dilutions. Thereafter, 95 colorectal cancer patients and a control group including healthy subjects (n=11), patients with other gastrointestinal neoplasms (n=11) or inflammatory bowel disease (n=9) were analysed. Specific cDNA primers for CEA transcripts were used to apply RT-PCR to peripheral blood samples. Tumour cells were detected down to five cells per 10 ml blood, thus indicating a sensitivity limit of approximately one tumour cell per 10(7) white blood cells. CEA mRNA expression was detected in 39 out of 95 colorectal cancer patients (41.1%), there being a significant correlation with the presence of distant metastases at inclusion. None of the healthy volunteers and only 1 of 11 patients (9.1%) with other gastrointestinal neoplasms had detectable CEA mRNA in peripheral blood. By contrast, CEA mRNA was detected in five of the nine patients (55.6%) with inflammatory bowel disease. These results confirm that it is feasible to amplify CEA mRNA in the peripheral blood, its presence being almost certainly derived from circulating malignant cells in colorectal cancer patients. However, CEA mRNA detectable in blood of patients with inflammatory bowel disease suggests the presence of circulating non-neoplastic colonic epithelial cells.

Value of postoperative surveillance after radical surgery for colorectal cancer: results of a cohort study.

PURPOSE: Early detection of recurrence after curative resection for primary colorectal cancer should improve patients' prognosis. However, the usefulness of postoperative surveillance programs has not been clarified yet. The present cohort study was aimed at assessing the effectiveness of systematic follow-up in patients with colorectal cancer who were operated on for cure, regarding both rate of tumor recurrence amenable to curative-intent surgery and rate of survival. METHODS: One hundred ninety-nine colorectal cancer patients who underwent radical primary surgery were followed according a well-defined postoperative surveillance program, which consisted of laboratory studies (including serum carcinoembryonic antigen assay) every three months, physical examination and abdominal ultrasound or computed tomography every six months, and chest radiograph and total colonoscopy once per year. Cohorts were defined according to patients' compliance with the proposed follow-up program. A multivariate regression model was constructed to predict survival. RESULTS: One hundred forty patients were considered to be compliant with the surveillance program, whereas the remaining 59 patients occasionally attended follow-up investigations or did not comply at all. Although there were no differences in the overall recurrence rate (38 vs. 41 percent; P = 0.52), curative-intent reoperation was possible in 18 patients (34 percent) of those with tumor recurrence in the compliant cohort but in only 3 patients (12 percent) in the noncompliant cohort (P = 0.05). Similarly, the probability of survival was higher in the compliant cohort, both regarding overall (63 vs. 37 percent at 5 years; P < 0.001) and cancer-related (69 vs. 49 percent at 5 years; P < 0.02) rates. Cox regression analysis disclosed that only a more advanced TNM stage (odds ratio, 8.17; 95 percent confidence interval, 1.13-59.29) and noncompliance with the postoperative surveillance program (odds ratio, 2.32; 95 percent confidence interval, 1.50-3.60) had an independent negative impact on survival. CONCLUSION: Systematic postoperative surveillance in patients with colorectal cancer who were operated on for cure increases both the rate of tumor recurrence amenable to curative-intent surgery and rate of survival.

[Screening for colorectal cancer in Catalonia. Results of a population survey]. / Situación actual del cribado del cáncer colorrectal en Cataluña. Resultados de una encuesta poblacional.

BACKGROUND: In recent years, the usefulness of programs for the prevention of colorectal cancer has been demonstrated in the general population as well as on specific risk groups. However, its implantation rate is unknown in our area. This study was aimed at evaluating the level of introduction of colorectal cancer screening. METHOD: A telephonic survey has been carried out using a pre-established questionnaire to find out if the interviewed had undergone a fecal occult blood test, digital rectal examination, barium enema and/or colorectal endoscopy with the final aim of colorectal cancer prevention. Moreover, the knowledge of both above mentioned explorations and the colorectal cancer clinical manifestations have also been evaluated. Individual characteristics determining these aspects have also been investigated. RESULTS: Only two (0.8%) of the 250 subjects included had undergone a screening procedure (digital rectal examination). In contrast, in female population, 142 women (82%) had been included in a surveillance program to detect early signs of breast or gynecological cancer. In addition, a low level of knowledge of these explorations has been observed (digital rectal examination: 58%; colorectal endoscopy: 56%; barium enema: 44%; fecal occult blood test: 41%). This low level was also observed regarding to clinical manifestations associated with colorectal cancer. CONCLUSIONS: In contrast with gynecological cancer, colorectal cancer screening has not yet been introduced in Catalonia. Moreover, the knowledge of the available information regarding to preventive strategies is very low.

[Identification of patients with a high risk of needing prolonged mechanical ventilation after coronary surgery]. / Identicación de pacientes con mayor riesgo de precisar ventilación mecánica prolongada tras cirugía coronaria.

OBJECTIVES: To identify patients at greater risk of developing respiratory complications, defined as the need for mechanical ventilation (MV) longer than 48 h, following revascularization surgery. MATERIAL AND METHODS: This was a prospective analysis of 39 variables in 107 consecutive operations taking place over 9 months. We studied the association of these variables with the need for prolonged MV after surgery, by way of single variable and multivariate analysis. RESULTS: The incidence of prolonged MV was 7.7% and the 25% rate of mortality in the group of patients with this complication was significantly higher than the 0% mortality in the remaining patients. After single variable analysis of the data, the following variables were more significantly (p < 0.01) associated with the need for postoperative MV longer than 48 h: presence of other cardiac lesions other than coronary disease, performance of other heart surgery along with the coronary revascularization, surgical complications, high left auricular pressure soon after surgery. The variables found to have the highest independent predictive value based on the multivariate analysis were performance of other heart surgery along with the coronary revascularization and surgical complications. CONCLUSION: Our study indicates that the variables that point to poor left ventricular function and negative repercussions on extracorporeal circulation are associated with a greater incidence of prolonged MV after coronary surgery. Keeping these variables in mind allows high risk patients to be identified. More extensive monitoring of breathing function and therapeutic measures can then be implemented for better postoperative management.