Muscle hypertrophy in men and women

It is widely believed that women experience less skeletal muscle hypertrophy consequent to heavy-resistance training than men. The purpose of this study was to test this hypothesis using both traditional indirect indicators as well as a direct measure of muscle size. Seven male experimental (ME), 8 female experimental (FE), and 7 control subjects were studied before and after a 16-wk weight training program, in which ME and FE trained 3 days.wk-1 at 70 to 90% of maximum voluntary contraction using exercise designed to produce hypertrophy of the upper arm and thigh. Strength increased significantly (P less than 0.05) in ME and FE, respectively, on elbow flexion (36.2 and 59.2%), elbow extension (32.6 and 41.7%), knee flexion (12.8 and 24.4%), and knee extension (28.8 and 33.9%) tests. Absolute changes were significantly greater in ME than FE in 2 of the 4 tests, whereas percentage changes were not significantly different. Substantial muscle hypertrophy occurred in the upper arms of both ME and FE as evidenced by significant increases in upper arm circumference (7.9 and 7.9%), bone-plus-muscle (B+M) cross-sectional area (CSA) estimated by anthropometry (17.5 and 20.4%), and muscle CSA determined from computed tomography scanning (15.9 and 22.8%). Changes by ME and FE were not significantly different, except for the absolute increase in estimated B+M CSA, which was significantly greater in ME (11.2 vs 7.4 cm2). No muscle hypertrophy occurred in the thigh of either ME and FE as evidenced by non-significant changes in thigh circumference (1.7 and 2.3%), B+M CSA (4.9 and 6.1%), and muscle CSA (2.9 and 2.9%). Changes by ME and FE in body weight, fat-free weight, and fat weight were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Directional instability of rear caster wheelchairs

Although less common than conventional front caster wheelchairs, rear caster wheelchairs are still in use for several reasons. Many people find manual rear caster wheelchairs easier to maneuver indoors at slow speeds. This is especially true when the user attempts to maneuver the wheelchair very close to an object, such as a table. Electric wheelchairs often have rear casters to accommodate for front wheel drive. If the larger drive wheels are located at the front of the wheelchair, obstacles such as a curb can be negotiated much more easily. However, a major disadvantage of rear caster wheelchairs is that they are generally known to be directionally unstable, especially at high forward speeds. This paper presents the results of a study to determine specific measures that can be employed to improve the stability of this type of wheelchair. The instability of rear caster wheelchairs is due primarily to road forces that act on the tires when the wheelchair is displaced from its line of motion by a bump or other irregularity in the road surface. The paper discusses the experimental investigation of these road forces as well as a dynamic model used to study the instability problem. The results of a computer simulation program used to perform a parametric study of different design variables are discussed. Center of gravity position, caster trail distance, and caster pin friction are found to have a dominant influence on rear caster wheelchair directional control. Several simple but significant design recommendations are presented.     

Steroid trials in the assessment of reversibility of air flow limitation: a survey of current clinical practice of chest physicians

To evaluate how steroid trials are currently used in the assessment of reversibility of air flow limitation, a postal questionnaire was sent to 355 consultant members of the British Thoracic Society working in England and Wales; 253 questionnaires were returned (71% response rate). Two respondents did not undertake steroid trials; of the remaining 251, 75% prescribed 30-40 mg oral prednisolone, with the commonest treatment period being 2 weeks. A high dose steroid inhaler was sometimes used as an alternative by 31% of respondents. Although 71% of respondents made lung function measurements on several occasions before starting steroids and 76% made measurements during treatment, 78% assessed patients on only one occasion at the end of the trials to ascertain its outcome. Weight, blood pressure and glycosuria were measured less frequently after the steroid treatment compared to the pre-trial period. Blood glucose and serum electrolytes were infrequently measured both before and after treatment. Wide variations exist in steroid trial regimens and current practice may neither provide definitive evidence of treatment benefit nor an adequate safeguard for patients against potential side-effects.     

von Willebrand factor as a marker of endothelial cell activation following BMT.

Endothelial cell activation may play a role in thrombotic complications of BMT such as hepatic veno-occlusive disease (VOD), right atrial line thrombosis and microangiopathic haemolysis. To assess this, von Willebrand factor antigen (vWF:ag) was measured in 72 patients (25 allografts, 46 autografts and one syngeneic) during the first 6 weeks post-transplant. There was a significant rise in vWF:ag in both allografts and autografts but a greater increase was seen in the allografts. The changes in vWF:ag did not correlate with changes in C reactive protein showing that this was not merely an acute phase response. vWF multimers were normal in a subgroup of uncomplicated transplants showing that there was no large scale endothelial cell disruption. Patients with VOD did not have changes in vWF:ag that were consistently different from uncomplicated controls. Three of four patients who developed line thrombosis had higher levels of vWF:ag compared with control groups; multimeric structure of the vWF was again normal. These results show that there is endothelial cell activation post-BMT and that this is greater in allografts compared with autografts, thus suggesting a possible mechanism for the higher incidence of VOD in this group. There were no useful predictive markers of VOD or thrombosis in individual patients.     

A cytoskeletal actin gene in the mosquito Anopheles gambiae

Five actin genes have been identified in the mosquito Anopheles gambiae , and a constitutively expressed actin gene has been chosen for detailed analysis. We have physically mapped and sequenced this gene and six associated cDNAs, including translated coding regions, as well as the 5 and 3 flanking sequences. Analysis of stage-specific RNA shows this gene to be present in all stages of mosquito development and in an established A. gambiae cell line, thus indicating a cytoskeietal actin. In the sequence of the translated coding region and in pattern of expression, this gene is very similar to the cytoskeietal actin genes of Droso-phila melanogaster , and in sequence, equally similar to the Artemia cytoskeietal actin gene 403 (99.2% identity among the three amino acid sequences). Sequencing of this A. gambiae actin gene (designated actWior its location in chromosome division 1D) and selected cDNAs shows that it possesses three alternative leader sequences; thus the gene appears to have three alternative promoters. These promoters should ultimately prove useful in the production of transgenic constructs for constitutive expression.     

Use of intracavity saline instillation and transvaginal ultrasonography to detect tamoxifen-associated endometrial polyps.

There is sometimes a discrepancy between the apparent thickness of postmenopausal endometria, as determined by transvaginal ultrasonography, and the examination of endometrial biopsies. We describe a case which showed that tamoxifen (20 mg/day over 12 months) decreased impedance to blood flow in the uterine arteries and increased the apparent thickness of the endometrium. Conversely, the analysis of biopsies suggested the presence of an atrophic endometrium. The introduction of sterile saline into the uterine cavity during a repeat ultrasound scan revealed the presence of a large, free-floating endometrial polyp, which was subsequently difficult to see by hysteroscopy.