Physiology of Alpine skiing

Physiological profiles of elite Alpine skiers reveal the importance of muscular strength, anaerobic power, anaerobic endurance, aerobic endurance, coordination, agility, balance, and flexibility. On-hill snow training and dryland training programmes should focus on the elevation of these fitness components. Physical characteristics of elite skiers reveal an average height and body mass. Today, successful skiers are taller and heavier than their predecessors. Slalom skiers tend to be leaner than skiers in other events while the downhill racers are the heaviest. Elite skiers have strong legs when peak torque is measured during isometric and isokinetic conditions involving knee extension, which may be a specific adaptation since the skier is in a crouched position for a prolonged period when racing. Leg strength correlates significantly with performance in the downhill and giant slalom events. The glycolytic contribution in the slalom and giant slalom events is about 40% of the total energy cost. Following a race, blood lactate concentration averages 9 to 13 mmol/L. A muscle lactate concentration of 24 mmol/kg wet muscle tissue has been reported. Elite skiers have higher lactate values than advanced or novice skiers. The aerobic demands of competitive Alpine skiing may approach (90 to 95%) of the athlete's maximal aerobic power. Maximal heart rate is achieved during the latter part of the race. Elite skiers have a high VO2max. This may reflect their training programme and not the actual demands of the sport. When turning, muscular activity acts to impede blood flow and oxygen delivery. As a consequence, anaerobic metabolism is increased. Glycogen studies show significant utilisation from both slow and fast twitch muscle fibres. Skilled and unskilled skiers differ with respect to glycogen utilisation. Skilled skiers have greater glycogen depletion in the slow twitch fibres compared to unskilled skiers. Muscle glycogen decreases by about 32 mmol/kg wet muscle tissue following a day of ski training. Glycogen depletion may contribute to the injury pattern which peaks toward the end of the ski day. The risk of injury has been estimated at 17 injuries per 1000 skier days. When the severity criterion was an injury causing the skier to miss 3 days of skiing or visit a physician, the risk was 2 injuries per 1000 skier-days.(ABSTRACT TRUNCATED AT 400 WORDS)     

Acute hypertensive episode induced by sulpiride – a case report

A case study is described of a hypertensive episode associated with sulpiride which is a selective antagonist of cerebral dopamine receptors. The association with sulpiride was confirmed by withdrawal and rechallenge with the drug.     

A comparison of weights of debris extruded apically by conventional filing and Canal Master techniques

Sixty extracted human teeth were divided into three groups of 20 each. Apically extruded debris and irrigant were collected, dried, and weighed by the following three instrumentation techniques: (a) group 1, filing 1 mm short of the foramen; (b) group 2, Canal Master instrumentation to the foramen; and (c) group 3, filing to the foramen (for a relative comparison). The results indicated that all three groups were significantly different from one another. Group 1 had the least amount of debris extruded. Of the two groups instrumented to the foramen, group 3 had twice as much debris extruded as group 2. An apical dentinal plug was frequently found in group 1 and was probably a major reason why this group had the least amount of extruded debris. The significance of this dentinal plug and possible indications for instrumentation to the foramen are discussed.     

Recovery of lung pyridine nucleotides following acute exposure of adult and aged rats to ozone.

Male, pathogen-free Fischer 344 rats aged 6 and 24 mo were exposed to 1.5 or 3.0 ppm for 8 h and recovery rates of diphosphonucleotides (NAD+ and NADH) and triphosphonucleotides (NADP+ and NADPH) were measured and compared to controls. Recovery after 0.5 ppm was not examined because no significant changes occurred in either age group after this lower exposure. At zero time (immediately after exposures) both concentrations are depressed in adults and aged animals except for NADH in aged animals at 3.0 ppm; NADP+ in adults at 1.5 and 3.0 ppm was decreased, but not significantly. For NAD+ and NADH, recovery of whole lung concentrations is complete by 24 h following an 8-h exposure to 1.5 or 3.0 ppm of ozone. Only after 3.0 ppm of ozone was the ratio of the reduced to oxidized form (NADH/NAD+) still elevated after 24 h; however, it also returned to control levels by 96 h. For the triphosphonucleotides, an 8-h exposure to 1.5 ppm of ozone resulted in a sustained depression of whole lung concentrations of NADPH throughout the 96-h recovery period. Also, only after the 1.5 ppm exposure was the reduced to oxidized ratio (NADPH/NADP+) significantly depressed throughout the 96-h recovery period. Unexpectedly, recovery of whole lung levels returned to normal within 24 h after the 8-h exposure to both the 1.5 and the 3.0 ppm concentrations. With the exception of the sustained effect on NADPH levels, these data indicate that di- and triphosphonucleotide concentrations rapidly return to normal in the lung after severe, acute oxidant injury. There were no differences in recovery rates between the adult and the aged groups.     

Effect of amplification on tinnitus among new hearing aid users

A tinnitus questionnaire was completed by 200 new hearing aid users. The results indicated that 62% experienced tinnitus, with 43.5% reporting frequent or continuous presence. Thirteen of the 200 patients rated their tinnitus as severe. Approximately one-half of the respondents with tinnitus reported that their hearing aids provided either partial or total relief from tinnitus. If the tinnitus was rated severe, partial instead of total relief was the most commonly reported effect. A few individuals indicated residual inhibition. A subjective evaluation of the aids' performance revealed that relief from tinnitus was frequently rated an important aspect of the user's satisfaction.     

A comparison of lymphocyte subset distribution in rat lacrimal glands with cells from tissues of mucosal and non-mucosal origin

The subset distribution of lymphocyte populations isolated from rat lacrimal glands (LG) was compared with those from tissues of both mucosal and non-mucosal origin. In spleen (SPL), mesenteric (MLN) and cervical lymph node (CLN) populations the percentages of cells bearing W3/13 (pan T) and OX19 (pan T) were greater than the percentages obtained for cells bearing the OX7 (Thy-1) marker. In contrast, for lacrimal (LG), salivary (SG) and mammary gland (MG) populations, cells bearing OX7 predominated over those bearing the W3/13 and OX19 markers, with the exception of day 1 post-partum MG tissue which displayed equal numbers of OX7 and OX19 cells. Except for MG, in which OX8 (T non-helper) predominated over W3/25 (T helper) populations, the proportions of these two subsets in the other tissues were generally similar. Analysis of SPL and LG cells for coexpression of OX7 with OX19 or L chain indicated that significant percentages of OX7 bearing cells also expressed T or B cell markers. However, the higher values noted for the OX7 population in LG were not attributable to increased numbers of cells coexpressing pan T or B cell markers. These findings show that lymphocyte subset distribution in LG and other glandular mucosal tissues is distinct from that of non-mucosal tissues, in that mucosal tissues contain a predominance of cells bearing the Thy-1 (OX7) phenotype.     

The effects of transforming growth factor- and interleukins 2,5 and 6 on immunoglobulin production in cultured rat salivary gland tissues

The effects of transforming growth factor-β, alone, and in combination with selected interleukins on immunoglobulin production were investigated using an in vitro rat tissue fragment culture system with either parotid, submandibular or sublingual gland tissue. In the majority of culture groups, TGF-β alone, or in combination with either interleukin 2 (IL-2), IL-5, IL-6 or IL-5 and IL-6 together, significantly increased immunoglobulin A (IgA) levels over those obtained in untreated cultures. The levels of IgG and IgM were generally not affected, with the exception of one sublingual and two submandibular groups(s), where cytokine administration up-regulated either IgG or IgM production. These data indicate that transforming growth factor-β in combination with IL-2, IL-5, IL-6 or IL-5 and IL-6 can exert a stimulatory effect on IgA production in vitro, supporting a potential regulatory role for these cytokines in salivary gland IgA responses.