Acute Impact of Inhaled Short Acting B2-Agonists on 5 Km Running Performance

Whilst there appears to be no ergogenic effect from inhaled salbutamol no study has investigated the impact of the acute inhalation of 1600 µg, the World Anti-Doping Agency (WADA) daily upper limit, on endurance running performance. To investigate the ergogenic effect of an acute inhalation of short acting β₂-agonists at doses up to 1600 µg on 5 km time trial performance and resultant urine concentration. Seven male non-asthmatic runners (mean ± SD; age 22.4 ± 4.3 years; height 1.80 ± 0.07 m; body mass 76.6 ± 8.6 kg) provided written informed consent. Participants completed six 5 km time-trials on separate days (three at 18 °C and three at 30 °C). Fifteen minutes prior to the initiation of each 5 km time-trial participants inhaled: placebo (PLA), 800 µg salbutamol (SAL800) or 1600 µg salbutamol (SAL1600). During each 5 km time-trial HR, VO₂, VCO₂, V_E, RPE and blood lactate were measured. Urine samples (90 ml) were collected between 30-180 minutes post 5 km time-trial and analysed for salbutamol concentration. There was no significant difference in total 5 km time between treatments (PLA 1714.7 ± 186.2 s; SAL800 1683.3 ± 179.7 s; SAL1600 1683.6 ± 190.7 s). Post 5 km time-trial salbutamol urine concentration between SAL800 (122.96 ± 69.22 ug·ml^-1) and SAL1600 (574.06 ± 448.17 ug·ml^-1) were not significantly different. There was no improvement in 5 km time-trial performance following the inhalation of up to 1600 µg of salbutamol in non-asthmatic athletes. This would suggest that the current WADA guidelines, which allow athletes to inhale up to 1600 µg per day, is sufficient to avoid pharmaceutical induced performance enhancement.

Key points

• Inhaling up to 1600 µg of Salbutamol does not result in improved 5 km time trial performance.
• The position of Salbutamol on the World Anti-Doping Agency list of prohibited appears justified.
• Athletes who use up to 1600 µg Salbutamol in one day need to review their therapy as it would suggest their respiratory condition is not under control.

Key Words: Anti-Doping, WADA code, asthma, treatment, athlete care     

Isoelectric focusing of human hemoglobin: its application to screening, to the characterization of 70 variants, and to the study of modified fractions of normal hemoglobins

Isoelectric focusing on slabs of acrylamide gel was adapted for the screening of abnormal hemoglobins, the characterization of 70 human variants, and the study of minor fractions of normal hemoglobin. The screening method was as fast and inexpensive as conventional techniques, allowed the simultaneous analysis of some 50 samples of whole blood, and yielded resolution superior to that obtained by other methods with hemolysates. Among the 70 variants, 31 mutants could not be separated from HbS by cellulose acetate electrophoresis. The characterization technique of electrofocusing allowed us to distinguish between most variants. Only one mutant, Hb Galveston, could be confused with HbS. Hb Koln, the most frequent unstable mutant, exhibited a special pattern. HbA1C was separated from HbA. Preliminary results indicate that quantitation of HbA1C by gel scanning is feasible.     

Laser valvotomy with balloon valvoplasty for pulmonary atresia with intact ventricular septum: five years' experience.

OBJECTIVE: To assess immediate and medium term results of transcatheter laser valvotomy with balloon valvoplasty in selected infants with pulmonary atresia and intact ventricular septum. DESIGN: Prospective study. SETTING: Tertiary cardiac unit. PATIENTS: All infants with pulmonary atresia and intact septum with no more than minor tricuspid valve hypoplasia referred between November 1990 and June 1995. Laser valvotomy was attempted in nine infants of median age 4-5 days and median weight 3.6 kg. INTERVENTION: The pulmonary valve was perforated using a 0.018 inch fibreoptic guidewire attached to a NdYag laser and introduced through a catheter positioned beneath the valve. After perforation the valve was dilated with progressively larger balloons. MAIN OUTCOME MEASURES: Successful laser valvotomy and balloon dilatation, complications, pulse oximetry, right ventricular outflow velocities, and need for surgical treatment. RESULTS: Valvotomy was successful in all but one case, the failure being due to laser breakdown. After perforation the valve was dilated to 6-8 mm diameter. Prostaglandin E was withdrawn immediately in six of the eight duct dependent infants, and 28 and 49 days later in two. No patient required an aortopulmonary shunt. Two patients had repeat valvoplasty at 20 days and three months of age, respectively; one required infundibular resection and closure of the atrial septum at age four and one is awaiting similar treatment. CONCLUSIONS: Laser valvotomy with balloon valvoplasty is safe and effective treatment for selected patients with pulmonary atresia and intact ventricular septum and should be considered as first line treatment in place of surgical valvotomy.     

Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.     

Increased blood velocities in the heart and great vessels of patients with congenital heart disease. An assessment of their significance in the absence of valvar stenosis

During a previous investigation and during routine clinical Doppler echocardiography velocities distal to normal valves were found to be increased in patients with congenital heart disease. To investigate this observation the velocity proximal and distal to cardiac valves was recorded in 56 patients with congenital heart disease. No detectable pressure gradient had been found across these valves at catheterisation and no velocity gradient greater than 20 cm/s was found across them by range gated Doppler echocardiography. In 82% of the patients, however, the blood velocity across one or more valves exceeded normal limits. Increased velocities were found at the tricuspid inflow (55%), pulmonary artery (38%), mitral inflow (34%), and ascending aorta (11%). Factors predisposing to the presence of increased velocities in these areas were increased flow through the valve and decreased compliance of the receiving chamber. This study shows the necessity for recording velocity both proximal and distal to a valve before a gradient is calculated according to the modified Bernouilli equation.     

Familial adenomatous polyposis (Gardner's syndrome) and thyroid carcinoma

Summary The case history of a 24-year-old woman with Gardner's syndrome [familial adenomatous polyposis (FAP)] and papillary thyroid carcinoma is presented, representing the 37th report of this association. Although FAP is transmitted as an autosomal dominant trait with similar penetrance in both sexes, thyroid carcinoma has been found almost exclusively in women (94.3%). The majority have been papillary carcinomas (88.5%), which have become apparent during the third decade (average 23.6, range 16–40 years). Most (55.5%) thyroid carcinomas have been discovered 1–17 years after FAP was identified, although some have been found before (29.6%), or at the same time (14.8%) FAP was diagnosed. Multicentric papillary carcinomas have been reported in 64% (14 of 22) of FAP patients, a frequency at least twofold greater than usual. Although papillary carcinoma found before age 30 (as it was in most patients with FAP) typically has an excellent prognosis, one patient with FAP developed distant metastases from thyroid carcinoma and a 28-year-old woman's death was attributed to papillary carcinoma. The high frequency of multicentric papillary thyroid carcinoma in young patients with FAP and the potential for metastases and death due to thyroid carcinoma warrant aggressive diagnostic screening at regular intervals with neck palpation, ultrasonography, and if necessary, fineneedle aspiration biopsy. When thyroid carcinoma is found, total or near-total thyroidectomy should be considered because of the tumor's high likelihood of being multifocal. Since almost 30% of the thyroid carcinomas associated with FAP have been diagnosed 4–12 years before polyposis was identified, young patients presenting with thyroid carcinoma should be questioned regarding bowel function and a family history of gastrointestinal disease, and consideration should be given to periodic testing for fecal occult blood.The views expressed herein are those of the authors and do not necessarily reflect those of the Army or the Department of Defense.     

Use of parenteral nutrition in treatment of advanced regional enteritis

Eight patients with advanced regional enteritis characterized by multiple areas of involvement, previous surgery (5 of 8), and failure on medical therapy (6 of 8) were placed on total parenteral nutrition for a period of 30 days. In eight of nine courses administered, definite improvement marked by weight gain, diminished pain, decreased diarrhea, and increased serum albumin was found. However, clinical remission was transient in seven of eight successful courses, indicating that parenteral nutrition is not a definitive form of therapy. However, the results suggest that parenteral nutrition may be useful in patients with regional enteritis to a) restore nutrition, b) induce remission, and c) prepare a debilitated patient for surgery. Additional experience is required to determine the efficacy of parenteral nutrition for therapy of fistulae caused by regional enteritis.     

The colitis of Behcet's disease: A separate entity?

Summary An additional case of Behcet's disease with colonic involvement has been presented. This association is rare, as only 13 prior cases with adequate data were available for comparison. Controversy exists as to whether these cases represented true involvement of the colon by Behcet's disease, coincidental inflammatory bowel disease and Behcet's disease, or merely autoimmune phenomena associated with inflammatory bowel disease. Unusual colonoscopic lesions noted in our patient and other features enumerated in the text suggested to us that at least some of these cases represented primary Behcet's disease involving the colon.     

Gastric blood flow

Summary In summary, the vascular bed of the stomach is an area of great potential importance to both gastric and vascular physiologists. There are available many technics for its investigation. Simultaneous study of both hemodynamic and secretory phenomena can be conducted on the stomach. In the next few years information concerning the circulation of the stomach may help elucidate problems in the physiology and pathology of gastric secretion. Hightower observed recently: The topic of visceral circulation, particularly as it pertains to the digestive tract, has not been commented upon in recent...Reviews of Physiology. This subject has become increasingly important in the past few years and is an area with which physiologists interested in the digestive system will become more and more concerned.³³