Paratiroidectomía en pacientes renales crónicos en Argentina: estudios prequirúrgicos, tipos de cirugía, recurrencia y persistencia / Parathyroidectomy in chronic kidney disease patients in Argentina: pre surgical studies, types of surgery, recurrence and persistence

La paratiroidectomía (PTx) es el tratamiento de elección en pacientes con HPT 2º severo, refractario al tratamiento médico. Se cuenta con muy poca información en Argentina de este procedimiento, por lo cual se realizó este estudio. Material y Métodos: Se incluyeron 255 pacientes con PTx entre el año 2003 al 2007 de un registro voluntario. Se evaluaron los estudios de localización prequirúrgicos, de laboratorio de metabolismo fosfocálcico previo y posterior a la cirugía y el tipo de técnica quirúrgica utilizada. Se analizó la persistencia y recidiva del HPT postcirugía. Resultados: La tasa de PTx fue de 2,7/1000 pacientes año. 83% de los pacientes tuvieron ecografía de cuello y 59% Sesta Mibi con Tc 99. Hubo una correlación positiva (p<0.001) entre el número de glándulas detectadas por ecografía y Sesta Mibi. La paratiroidectomía realizada fue: subtotal en 77%, total con autoimplante en 14% y total sin autoimplante en 9%. Hubo descensos significativos de Ca y P, fosfatasa alcalina y PTH (1744 ± 788 pg/ml a 247 ±450 pg/ml; p<0.0001) postcirugía. A los 2,4 ±2,5 meses de la PTx, el 72% de los pacientes tenía PTH <250 pg/ml, 19,8% tenía persistencia y 8,3% había recidivado. De acuerdo al tipo de cirugía la persistencia y recidiva fueron para PTx subtotal 22% y 8,3%, PTx total con implante 11% y 11% y PTx total sin autoimplante 13% y 4% respectivamente. La realización de Sesta Mibi no influyó en los resultados de la PTx. No se observaron diferencias entre los centros en relación con persistencia y recidiva. Conclusiones: La tasa de PTx fue muy baja, la ecografía fue el método de localización prequirúrgico preferido y la PTX subtotal la técnica quirúrgica más utilizada. La PTx fue exitosa en la mayoría de los pacientes y la persistencia y recidiva no estuvieron relacionadas con la técnica.

Parathyroidectomy (PTx) is the selecte treatment for patients with severe secondary hyperparathyroidism, refractory to medical treatment. There is not enough information about this procedure in Argentina, that is the reason why we performed this study. Material and Methods: 255 patients with PTx were included from the year 2003 to 2007 on a voluntary register. Studies of pre-surgical localization, phosphocalcic metabolism laboratories before and after surgery were evaluated, and the type of surgical technique used. The persistence and recurrence of post-surgical hyperparathyroidism was analyzed. Results: The PTx rate was 2,7/1000 patients year. 83% of the patients had neck echography and 59% Sestamibi scans with Tc 99. There was a positive correlation (p<0,001) between the number of detected glands by echography and Sestamibi. The parathyroidectomy performed was: subtotal in 77%, total with self-implant in 14% and total without self-implant in 9%. There were significant falls of Ca and P, Alkaline Phosphatase and PTH (1744±788 pg/ml to 247±450 pg/ml; p<0.0001) post-surgical. 2.4 ±2,5 months after the PTx, 72% of patients had PTH <250 pg/ml, 19,8% had persistence and 8,3% had recurrence. According to the type of surgery, the persistence and recurrence were for subtotal PTx 22% and 8,3%, total PTx with implant 11% and 11%, and total PTx without selfimplant 13% and 4% respectively. The performance of the Sestamibi scan did not affect the PTx results. No noticeable differences were observed among the centers for persistence and recurrence. Conclusions: The PTx rate was very low, echography was the preferred method of pre-surgical localization, and subtotal PTx was the most used surgical technique. PTx was successful in most of the patients, and persistence and recurrence were not related to the technique.

Individual differences in visual information processing rate and the prediction of performance differences in team sports: a preliminary investigation.

This study used a backward-masking paradigm to examine individual differences in rate of visual information processing among university basketball, ice hockey and Canadian football players. Displays containing four letters were presented for stimulus durations ranging from 25 to 300 ms. Following stimulus offset, a masking stimulus was presented for 200 ms. The subjects were instructed to write down as many letters as possible from the briefly presented stimulus display on a specially prepared response grid. The results indicated consistent individual differences in rate of visual information processing. More importantly, it was found that rate of visual information processing as indexed by the backward-masking technique, has promising validity for predicting general performance excellence in university ice hockey and basketball players. Individual differences in rate of visual information processing were interpreted as reflecting the operation of attentional factors.

A survey of the race profiles of cyclists in the pursuit and kilo track events.

A survey was made of national- and international-calibre men and women track cyclists who rode in three separate world-class competitions on the Argyll Velodrome, Edmonton, Canada. Race profiles were obtained from 222 riders who competed in the pursuit and 1000 m time trial (kilo) events. Mean lap times (MLT) and optimal race profiles (ORP) were constructed, and served as the bases of comparison between top- and bottom-ranked riders. The survey showed that riders whose race profile failed to approximate the ORP always lost to riders whose race profile did so. The most likely cause of poor race performances is the inefficient use of the cyclists' anaerobic energy resources.

A survey of age group ice hockey goal keepers.

How large are age group ice hockey goal keepers who defend goals in the Canadian amateur hockey system? This and similar questions regarding physical size were the subject of a survey of age group ice hockey goal keepers from six age categories recognized by the Canadian Amateur Hockey Association. Of these six categories, only four, namely Mite, Pee Wee, Bantam, and Midget were sampled with sufficient frequency to be reported here. A non-amateur seventh category entitled Professional was also examined using the same survey instruments. The goalers participating in the survey provided anecdotal information, were weighed, height measured, and then photographed while in their goal keepers' 'crouch', both with and without their full goal keeping equipment. Non-inferential statistics of central tendency and dispersion were used to examine normalcies of anthropometric measures, proportionality of growth process, and distribution of apparent body size as determined from the blocking area of the body (frontal perspective).

Consistent reproduction of movement sequences during acquisition of a pursuit tracking task.

A pursuit tracking task is used as a vehicle to investigate the manner in which response consistency is affected by practice. Detailed examination of movement patterns shows that subjects can reproduce the mid-phase of a movement relatively consistently while the accelerative and decelerative phases of the movement remain highly variable. The findings are discussed with reference to Sparrow's 1983 concept of efficiency in conjunction with Norman and Shallice's 1980 model of automated action.

Immediate reproduction of temporal information under four cognitive strategies.

The main purpose was to determine the retention characteristics of temporal information when subjects experienced time under a retention interval of immediate reproduction and various cognitive strategies for time estimation. Four levels of cognitive strategy were used, viz., conscious, mental counting, counting aloud without auditory cues, and counting aloud with auditory cues. The latter three cognitive strategies were experimenter-defined, time-aiding techniques. Subjects were instructed to refrain from employing time-aiding techniques under a conscious cognitive strategy for time estimation. Visual durations of 1, 2, and 4 sec. were estimated by 12 subjects under the method of reproduction. Two measures of performance were computed, viz., variable and constant errors. The general conclusions were: (a) the effectiveness of mental counting, counting aloud without auditory cues, and counting aloud with auditory cues as cognitive strategies over conscious cognitive strategy in terms of variability depends on the duration used, and (b) in terms of accuracy and variability an increase in the number of cues under time-aiding techniques does not necessarily produce better performance.

Three daily exchanges on continuous ambulatory peritoneal dialysis. 8 months of treatment in 6 patients.

After the first report by Popovich et al., continuous ambulatory peritoneal dialysis (CAPD) is widely becoming another challenge for end-stage renal disease (ESRD) treatment. Trials to confirm the first results in a longer follow-up are in course in many countries. In this paper we showed our experience with three daily exchanges in 6 patients treated for more than 8 months. This modification of the technique allows better compliance of the patient and reduces the cost of treatment. During this period of time, CAPD, three daily exchanges, was an adequate procedure for an unselected group of patients. In our experience, peritonitis episodes were the main complication. For this reason, 33% of the patients were switched to hemodialysis. The use of plastic bags and strict adherence to aseptic measures will improve the results.

The basic stance of age-group ice hockey goalkeepers.

Over 300 goalkeepers from the seven age-groups were sampled as part of a larger age-group normative survey. The photographic evidence delineates three basic goalkeeping stances in the younger age-groups. For a variety of reasons, one of the stances becomes dominant to all others and appears to be the one used by NHL, WHA and world international championship goal tenders.

A priori probability effects on simple reaction time.

Three factors - immediate foreperiod (1.0 and 4.0 sec), previous foreperiod (1.0 and 4.0 sec) and a priori probability (0.8 and 0.2) - were employed in a variable foreperiod simple RT design. The possibility was examined that a priori probability functioned independently of the previous foreperiod effect, an hypothesis advanced as an explanation for the inverse relationship between simple RT and foreperiod length. This possibility was confirmed in the present investigation. In addition, the results supported the contention that it is what the subject knows, not what he does not know, which controls simple RT.