Prostaglandins and angioplasty. An experimental study in canine arteries

To prevent platelet aggregation following percutaneous transluminal angioplasty (PTA), cyclooxygenase inhibitors such as acetylsalicylic acid (ASA) and indomethacin are recommended. However, ASA blocks both the proaggregating effects of thromboxane (TXA2) and the antiaggregating and vasodilating effects of prostacyclin (PGI2). The authors measured the contractile response of dilated canine carotid arteries in situ and in vitro using an isometric force transducer. Following PTA, contraction of the arterial wall was significantly reduced (p less than 0.01). By blocking cyclooxygenase with indomethacin (3 micrograms/ml), contraction was greatly improved (p less than 0.001). These results suggest that PTA may result in marked release of prostacyclin by the damaged arterial wall, which could account for the decreased responsiveness of the artery to exogenous norepinephrine.     

Case report: Liver function abnormalities in a severe case of hyperreactio luteinalis

Rare causes of liver dysfunction in pregnancy may pose a challenge to the consulting gastroenterologist or hepatologist from both the diagnostic and therapeutic standpoints. We describe here liver function abnormalities in a case of hyperreactio luteinalis with light and electron microscopic findings.     

Mounting and calibration of stairs on piezoelectric force platforms

To calculate the centre of pressure using piezoelectric force plates mounted on pads, no net tensile stresses may be imposed on the surface of the plate. This condition is violated when stairs are attached to the plates, unless the plates are preloaded. Typical shear forces encountered when climbing stairs were used to determine required preloads of approximately 16.4 N/cm step height. Vertical and horizontal loads were applied at known locations on the steps, and points of application were calculated. Deviations were within ± 3 mm. The effect of point of application inaccuracy on calculated joint moments is considerable. A 2 cm medial shift in the point of application resulted in calculated peak knee abduction/adduction moment errors of 35%.     

Spondylolysis and Spondylolisthesis in Athletes

Lumbar spine isthmic conditions present a spectrum of disorders of the pars interarticularis in athletic populations. Spondylolysis should not be equated with spondylolisthesis because their pathophysiology and biomechanics are different as are their clinical courses and outcomes. Differentiation also must be made between lower- and higher-grade spondylolistheses because their outcomes are also dissimilar. Most of these isthmic conditions can be treated nonoperatively. Controversy exists about appropriate surgical management of higher grade listhesis. Long-term outcomes of sports participation by skeletally immature athletes with isthmic disorders with or without surgery are not known. The emergence of single level fusion and fixation methods with limited impact on spinal mobility may allow return to sports previously not available status post longer arthrodeses with compromise in needed lumbar motion.Return to play guidelines postoperatively should include the sport’s requirements that are involved, experience and competitive level of the athlete in that sport, severity of symptoms, magnitude of listhesis, and imaging signs of fusion maturity and spinal stability. An orthopaedic surgeon’s knowledge of the particular sport’s training demands and sport specific techniques is invaluable in understanding the athlete’s point of view as part of the partnership for clinical success.     

Altered maternal psychological profile as health risk factor in poor urban infants

To test the hypothesis that the increased health risk of children selected by a previously calculated and validated predictive model is associated with some maternal psychological characteristics, the universe of 107 mothers of children selected by this model was evaluated by means of Goldberg's General Health Questionnaire (GHQ-30), Raven (Ra) and Rorschach (Ro) tests; 37.4% were cases according to GHQ-30, 80.9% were < 50th percentile in Ra and 85% exhibited deviant responses in Ro tests. Children whose mother's IQ was < 50th percentile suffered more episodes of total morbidity (Tm) and of diarrhoea (p = 0.0364). Children whose mothers were normal in Ro had less Tm (p = 0.0364) and fewer respiratory symptoms (p = 0.0300) and tended to have less diarrhoea (p = 0.0690). In poor urban families in Santiago psychological maternal characteristics are associated with an increased health risk for the infants. Supportive programmes should consider both biological characteristics of the infants and maternal psychological needs.     

Pain after barium enema: effect of CO2 and air on double-contrast study

One hundred fifty-one consecutive patients scheduled for double-contrast barium enema studies were assigned randomly to insufflation with either air or carbon dioxide (CO2) in a double-blind, prospective trial. Within 24 hours after the enema study, the patients were contacted by telephone by an interviewer, who completed a standard questionnaire. Radiographs from the enema studies were assessed for quality by two radiologists. Pain experienced after the procedure was graded from 0 (none) to 4 (severe). Clinically relevant (grades 2-4) pain was experienced by 30% of patients after insufflation with room air, compared with 11% of patients in whom CO2 was used for insufflation (P = .005). The mean pain score for CO2 was 0.4, and for room air, 1.2 (P less than .005). Although five patients experienced grade 4 pain after insufflation with air, no patient reported severe pain after CO2 insufflation. Post-evacuation films confirmed there was significantly less residual gas in the CO2 group. The quality of radiographs was equal in the two groups. CO2 has advantages for use in the double-contrast barium enema examination.