Vertebral deformities in interspecific diploid and triploid salmonid hybrids

Vertebral deformities in salmonid interspecific hybrids, some of which were triploidised, were assessed across three separate year classes during the freshwater life stage. Initially, eggs from a farmed Atlantic salmon Salmo salar were crossed with the sperm from a S. salar, arctic char Salvelinus alpinus or brown trout Salmo trutta. For S. salar × S. trutta, half the eggs were triploidised. In a second- and third-year class, the eggs from a farmed S. salar were crossed with the sperm from either a S. salar or a S. trutta, and half of each group was triploidised. In the two initial-year classes, all hybrids were larger than the S. salar controls, and triploid S. salar × S. trutta were larger than diploid counterparts. In the third-year class, the S. salar × S. trutta were smaller than the S. salar, in contrast to the initial 2 year classes, although the triploid hybrids were still larger than the diploids. In the third-year class, a high degree of spontaneous triploidy was also observed in the putative diploid groups (between 16 and 39%). Vertebral deformities were consistently higher in pressure-shocked triploids than diploids, irrespective of hybridisation, but there was no consistent effect of hybridisation among experiments. Although this study was not able to explain the contrasting results for vertebral deformities between year classes, triploid S. salar × S. trutta can demonstrate impressive freshwater growth that could be of interest for future farming programmes.     

Vertebral morphometry in diagnosis of spinal fractures

Vertebral morphometry was performed on lateral thoracic and lumbar radiographs of 153 women with a preliminary diagnosis of spinal osteoporosis. Measurements included anterior and posterior vertebral height, width, area, wedge angle, percent reduction of anterior to posterior height (PRH) and percent difference in anterior height between adjoining vertebrae (PDAH). A vertebral fracture was identified if any of the measurements which control for interindividual variation in vertebral size (wedge angle, PRH, PDAH) were below the normal range.Among individuals with mild osteoporosis (0–2 fractures) PDAH identified 86% of the fractures and 95% of the individuals with fractures. Other measurements identified less than 71% of the fractures and less than 80% of the individuals with fractures. Although the results reflect a relative rather than a true sensilivity it appears that PDAH is the better diagnostic measurement for fractures in the earlier stages of spinal osteoporosis.     

Relevance of bone mineral density, bone quality and falls in reduction of vertebral and non-vertebral fractures

All epidemiological studies conclude that without prompt, concerted and well-designed prevention programs, the increasing cost related to osteoporotic fractures will become an unbearable burden for the community within the next fifteen years. However, the most effective way of setting up such preventive strategies is not yet unequivocally defined. Low bone mass and microarchitectural damage of bone tissue may account for a large part of the epidemiology of vertebral fractures. Extraskeletal determinants, including low muscle strength, poor balance and gait, all resulting in an increased propensity to fall, also play a major role in the occurrence of hip fracture. Depending on the localization of the fractures, the relative importance of skeletal and extraskeletal risk factors can significantly differ. For prevention of vertebral fractures, drugs affecting bone mass and skeletal architecture may provide a substantial benefit while hip fracture prevention will be more successfully targeted by multi-faceted strategies concentrating not only on the skeletal dimension of the fracture but also aiming, either pharmacologically or through multi-intervention programs, at a reduction in the incidence and in the consequences of falls in the elderly.     

Biomechanical predictors of retrospective tibial stress fractures in runners

Both kinematics and kinetics of the lower limb have been shown separately to be related with a history of tibial stress fractures (TSFs) in female runners. However, it is likely that these factors interact together to increase the risk of a TSF. This study was conducted to determine which combination of kinematic and kinetic factors are the best predictors of retrospective TSF in female distance runners. Total 30 female runners who had previously sustained a TSF were recruited, along with an age and mileage matched control group (n=30). Subjects ran overground at 3.7m/s while kinematic and kinetic data were recorded. Five trials from each subject were used for data analysis and ensemble means were calculated for both groups. The kinematic variables of peak hip adduction (HADD), peak knee internal rotation (KIR) and knee adduction (KADD), peak rearfoot eversion (RFEV) were entered into a binary logistic regression along with the kinetic variables of vertical instantaneous load rate (VILR) and absolute free moment (FM). The variables HADD, FM and RFEV were able to correctly predict a history of TSF in 83% of cases. Increases in HADD, FM and RFEV (odds ratios of 1.29, 1.37 and 1.18) were associated with an elevated risk of having a history of TSF. The addition of VILR, KIR and KADD did not improve the ability to predict previous injury. Based on these results, HADD, FM and RFEV appear to be the most important of the variables of interest in terms of predicting retrospective TSF in female runners.     

Vertebral deformities in a school shark,Galeorhinus galeus: circumstantial evidence for endoskeletal resorption?

The appearance of deformed vertebrae from a single mature female school shark, Galeorhinus galeus , are described. Two unusual, pronounced bumps were noticed in the caudal region of this shark. There were no scars in the skin over these protrusions, suggesting that the lesions had arisen internally. Radiographie and histologie investigation of these lesions showed that mineralized tissue had probably been lost following an injury to the tail. Histological observations provided circumstantial evidence that mineralized tissue had been removed by internal processes, but did not reveal the agency by which skeletal tissue had been resorbed. Since the capacity to resorb mineralized tissue is characteristic of animals possessing bone, the apparent loss of mineralized tissue seen in this shark provides circumstantial evidence for the existence of bone cell lineages in school sharks. This evidence is discussed in relation to the possible implications for evolutionary and fisheries biology.     

Vertebral end-plate fractures as a result of high rate pressure loading in the nucleus of the young adult porcine spine

In a healthy spine, end-plate fractures occur from excessive pressurization of the intervening nucleus. Younger spines are most susceptible to such type of injury due to the highly hydraulic nature of their intervertebral discs. The purpose of this paper was to confirm this fracture mechanism of the healthy spine through the pressurization of the nucleus in the absence of external compressive loading. Sixteen functional porcine spine units were dissected and both injection and pressure transducer needles were inserted into the nucleus of the intervertebral disc. Hydraulic fluid was rapidly injected into the nucleus until failure occurred. Peak pressure and rate of pressure development were monitored. Spine units were dissected to determine the type and location of fracture. Fifteen of the 16 spine units fractured (the remaining unit had a degenerated disc). Of the 15 fractures, 13 occurred at the posterior margin of the end-plate along the lines of the growth plates. A slightly exponential relationship was found between peak pressure and its rate of development (R(2) = 0.544). Also, in each of the growth-plate fractured specimens, nuclear material was forcefully emitted, during fracture, from the intervertebral disc into the vertebral foramen. The posterior end-plate fractures produced here are similar to those often seen in young adult humans. This provides insight into a mechanism of fracture development through pressurization of the nucleus that might be seen in older adolescents and younger adults during athletic events or mild trauma.     

Assessing peridomestic entomological factors as predictors for Lyme disease.

The roles of entomologic risk factors, including density of nymphal blacklegged ticks (Ixodes scapularis), prevalence of nymphal infection with the etiologic agent (Borrelia burgdorferi), and density of infected nymphs, in determining the risk of human Lyme disease were assessed at residences in the endemic community of South Kingstown, RI. Nymphs were sampled between May and July from the wooded edge around 51 and 47 residential properties in 2002 and 2003, respectively. Nymphs were collected from all residences sampled. Tick densities, infection rates, and densities of infected nymphs were all significantly higher around homes reporting Lyme disease histories in 2003, while only infection rates were significantly higher in 2002. However, densities of infected nymphs did not significantly predict the probability of Lyme disease at a residence (by logistic regression) in either year. There were no significant differences in entomologic risk factors between homes with state-confirmed Lyme disease histories and homes with self-reported cases (not reported to the state health department). Therefore, although entomologic risk factors tended to be higher at residences with cases of Lyme disease, entomological indices, in the absence of human behavior measures, were not useful predictors of Lyme disease at the scale of individual residences in a tick-endemic community.     

Factors in childhood as predictors of asthma in adult life.

OBJECTIVE--To determine which factors measured in childhood predict asthma in adult life. DESIGN--Prospective study over 25 years of a birth cohort initially studied at the age of 7. SETTING--Tasmania, Australia. SUBJECTS--1494 men and women surveyed in 1991-3 when aged 29 to 32 (75% of a random stratified sample from the 1968 Tasmanian asthma survey of children born in 1961 and at school in Tasmania). MAIN OUTCOME MEASURES--Self reported asthma or wheezy breathing in the previous 12 months (current asthma). RESULTS--Of the subjects with asthma or wheezy breathing by the age of 7, as reported by their parents 25.6% (190/741) reported current asthma as an adult compared with 10.8% (81/753) of subjects without parent reported childhood asthma (P < 0.001). Factors measured at the age of 7 that independently predicted current asthma as an adult were being female (odds ratio 1.57; 95% confidence interval 1.19 to 2.08); having a history of eczema (1.45; 1.04 to 2.03); having a low mild forced expiratory flow rate (interquartile odds ratio 1.40; 1.15 to 1.71); having a mother or father with a history of asthma (1.74 (1.23 to 2.47) and 1.68 (1.18 to 2.38) respectively); and having childhood asthma (1.59; 1.10 to 2.29) and, if so, having the first attack after the age of 2 (1.66; 1.17 to 2.36) or having had more than 10 attacks (1.70; 1.17 to 2.48). CONCLUSION--Children with asthma reported by their parents in 1968 were more likely than not to be free of symptoms as adults. The subjects who had more severe asthma (especially if it developed after the age of 2 and was associated with reduced expiratory flow), were female, or had parents who had asthma were at an increased risk of having asthma as an adult. These findings have implications for the treatment and prognosis of childhood asthma, targeting preventive and educational strategies and understanding the onset of asthma in adult life.     

Oral infections as predictors of mortality

Objective: Oral infections may increase the levels of cytokines in the blood which, in turn, are associated with early mortality in the elderly. We investigated the possible association between oral infections and mortality. Design: Prospective cohort study over a 5‐year follow‐up. Setting: Research laboratory. Participants: A cohort born in 1910 (n = 94) was examined in the year 1995. Five years later mortality data were obtained from the population register for 49 deceased subjects. Main outcome measures: Urgent need of dental treatment, lifetime, erythrocyte sedimentation rate (ESR). Results: The multivariate analysis adjusted for general health and lifestyle factors showed that the risk for death of subjects in urgent need of dental treatments was 3.9 times higher than that of the other subjects. Among men ESR correlated significantly with urgent need of dental treatment. Conclusions: Oral infections among frail elderly people may be a sign of early mortality.     

Incidence and predictors of morphometric vertebral fractures in patients with ankylosing spondylitis

Introduction

Ankylosing spondylitis (AS) is associated with an increased incidence of vertebral fractures (VFs); however the actual incidence and predictors of morphometric VFs are unknown. The present study examined the incidence and predictors of new VFs in a large AS cohort.

Methods

In total, 298 AS patients who fulfilled the modified New York criteria were enrolled and spinal radiographs were evaluated biennially. Clinical and laboratory data and radiographic progression were assessed according to the Bath AS Disease Activity Index, erythrocyte sedimentation rate, C-reactive protein (CRP), and the Stoke AS spine score (SASSS). VF was defined according to the Genant criteria. The incidence of VFs at 2 and 4 years was evaluated using the Kaplan-Meier method. The age-specific standardized prevalence ratio (SPR) for AS patients in comparison with the general population was calculated.

Results

Of 298 patients, 31 (10.8%) had previous VFs at baseline. A total of 30 new VFs occurred in 26 patients over 4 years. The incidence of morphometric VFs was 4.7% at 2 years and 13.6% at 4 years. Multivariate logistic regression analysis showed that previous VFs at baseline and increased CRP levels at 2 years were predictors of new VFs (odds ratio (OR) =12.8, 95% confidence interval (CI) = 3.6-45.3 and OR = 5.4, 95% CI = 1.4–15.9). The age-specific specific standardized prevalence ratio of morphometric VFs in AS was 3.3 (95% CI 2.1–4.5).

Conclusions

The incidence of morphometric VFs increased in AS. Previous VFs and increased CRP levels predicted future VFs. Further studies are needed to identify the effects of treatment interventions on the prevention of new VFs.     

Stream diatom assemblages as predictors of climate

相似文献   

Hand deformities in patients with snakebite.

Over the past 25 years, 83 patients have been treated at our hospitals for poisonous snakebites of the hand. Prior to 1970, polyvalent antivenin was used, either alone or in conjunction with cryotherapy, steroids, or incision and suction methods. Hand deformities, due to tissue necrosis, were encountered in 15 of 22 patients (68%) treated by these methods. In contrast, excisional therapy, without the use of polyvalent antivenin, was the sole method of treatment in 61 patients seen since 1970. The incidence of hand deformity in them was 8.2%. We have concluded that early excision of the envenomated tissues will not only curtail systemic toxicity from the injected venom, but will also minimize the extent of local tissue damage.     

Absolute vs. relative machine strength as predictors of function in older adults

This study examined the relationship between absolute and relative (1 repetition maximum/LBM) strength vs. 13 different functional measurements in 143 older adults (mean = 70.28, standard deviation = 7.90 years). Strength for 11 machine lifts was determined using a predicted 1-repetition maximal strength measurement. Zero-order correlation results between absolute and relative strength vs. function measures demonstrated very weak to moderate correlations in the range of 0.02-0.57 and 0.01-0.44, respectively, with the lowest correlations present between strength and balance measures and the highest correlations present between strength and the carrying task (p 相似文献