Repertoires of T cells directed against a large protein antigen, beta-galactosidase. I. Helper cells have a more restricted specificity repertoire than proliferative cells

The proliferative and helper T cell repertoires were compared in the CBA/J mouse for the response to the large protein antigen, tetrameric beta-galactosidase (GZ = 1021 a.a/monomer). The systems assessed the ability of cyanogen bromide (CB) peptides of GZ to: 1) prime for a T cell proliferative response to GZ; or 2) generate T cell help, measured by the production of anti-FITC PFC in the in vitro response to GZ-FITC. Priming for in vitro proliferation was attempted with 11 CB peptides comprising 70% of the GZ molecule. Strong priming was found with five peptides and intermediate priming was found with four other peptides; two peptides were without effect (CB-20 = a.a 767-862, and CB-4 = a.a. 188-202). Despite this indication of generally dispersed recognition of GZ epitopes, only two CB peptides, CB-2 (a.a. 3-92) and CB-10 (a.a. 378-418) were able to induce a T helper cell response. The surprising dearth of helper T cell-inducing epitopes may be peculiar to the limited fluorescein (FITC) substitution on GZ-FITC (17-25 FITC residues per tetramer) or it may reflect the constraints involved in T cell recognition required for T-B collaboration. Also considered was the possibility that the helper T cell repertoire might be distinct from the proliferative repertoire, the latter reflecting DNA synthesis and recruitment by other functional T cell subpopulations.     

Differential effects of sauna-, diuretic-, and exercise-induced hypohydration

The physiological effects on submaximal and maximal exercise of three methods commonly used by athletes for achieving rapid weight loss were determined by measuring cardiorespiratory variables in 62 nonendurance athletes. A mean weight loss of 4.1% was achieved by those who followed either a sauna (SAU), diuretic (DIU), or exercise (ACT) protocol, compared with the average weight loss of 1.2% in the control group. At maximal exercise O2 consumption, O2 pulse, blood lactate concentration, and work load decreased in SAU and DIU groups relative to the ACT group, whereas only a few differences were observed at the aerobic threshold. Weight loss achieved over a 48-h period was less detrimental to an athlete than was a more rapid (24-h) weight reduction achieved through sauna bathing or the use of diuretics. We conclude that not only the quantity of weight loss but also the method itself may limit physical performance.     

Microlaparoscopy in sex reassignment surgery

Sex reassignment (male to female surgery) is a standard operation which is aimed at constructing female genitalia and obtaining a cosmetic and functional result that is similar to that of a normal female subject. The ideal surgical procedure has not yet been described, but the various techniques which have been proposed in the literature are similar. The most cumbersome maneuver of the procedure is that of creating a neovaginal cavity inside the perineum. This step is generally carried out by means of blunt dissection between the rectal wall and the prostate, but most of the surgery is blindly performed without visual control. In these conditions, the risk of rectal injury is high, and may lead to severe intraoperative complications. Microlaparoscopy allows for a direct observation of the perineal dissection from inside the peritoneal cavity, thus avoiding risk of rectal injury. The technique is simple to perform, is non-invasive, and only 15 minutes are added to the operation.