Aerobic Fitness Level Typical of Elite Athletes is not Associated With Even Faster VO2 Kinetics During Cycling Exercise

The aim of this study was to address the question if the VO₂ kinetics is further improved as the aerobic training status increases from trained to elite level athletes. Maximal oxygen uptake (VO₂max), work-rate associated to VO₂max (IVO₂max) and VO₂ kinetics of moderate (Mod) and maximal exercise (Max) were determined in fifty- five subjects. Then, they were assigned into three groups: low (LF), intermediate (IF) and high (HF) aerobic fitness level. In average, the VO₂max of LF, IF and HF groups were, respectively, 36.0 ± 3.1, 51.1 ± 4.5 and 68.1 ± 3.9 ml·kg·min^-1 (p ≤ 0.05 among each other). VO₂ kinetics mean response time of both exercise intensities were significantly faster (p ≤ 0.05) in HF (Mod, 27.5 ± 5.5 s; Max, 32.6 ± 8.3 s) and IF (Mod, 25.0 ± 3.1 s; Max, 42.6 ± 10.4 s) when compared to LF (Mod, 35.7 ± 7.9 s; Max: 57.8 ± 17.8 s). We can conclude that VO₂ kinetics is improved as the fitness level is increased from low to intermediate but not further improved as the aerobic fitness level increases from intermediate to high.

Key points

• Currently, it is reasonable to believe that the rate-limiting step of VO₂ kinetics depends on exercise intensity.
• The well known physiological adaptations induced by endurance training are likely the most extreme means to overcome rate-limiting steps determining VO₂ kinetics across exercise intensities.
• However, exercise adaptation leading individuals to the high-end of aerobic fitness level range (VO₂max > 65 ml.kg.min-1) is not able to further improve VO₂ kinetics during both, moderate and maximal intensity exercise.

Key words: Oxidative metabolism, VO₂ kinetics, aerobic training     

Effects of incremental curing on contraction stresses associated with various resin composite buildups.

OBJECTIVE: The purpose of this study was to photoelastically evaluate contraction stresses associated with various resin composite build-up procedures, including incremental curing and the use of flowable composite for pulpless molars. METHOD AND MATERIALS: Life-sized photoelastic models of an endodontically treated molar were fabricated. The cavity represented a conservative access preparation and included four lateral walls. The following materials were used for buildup: dual-cured hybrid composite (Cleafil DC Core [DC], BIS-CORE [BC]); light-cured flowable composite (AELITEFLO LV [ALV]); and chemical-cured flowable composite (CORE-FLO [CF]). The photoelastic models were built up with the following techniques: bulk-cured (BDd [dual-cured DC], BDc [chemically-cured DC], BBd [dual-cured BC], and BC [CF]); and incremental-cured (1 mm gingivally + 3.5 mm occlusally; IAB [ALV + BC], ICB [CF + BC], and IBB [BC + BC]). Isochromatic fringes developed in the models were recorded photographically in the field of a circular polariscope, and maximum fringe order was determined. Five specimens were tested for each condition. RESULTS: Stress intensity of the build-up methods fell into two categories: high (BDd, BBd, BC, and IAB) and low (BDc, ICB, and IBB). The difference between high and low groups was statistically significant, except between BC and ICB. The maximum fringe order was developed around the point angles at the cavity floor for all the conditions tested. CONCLUSIONS: Type and setting mechanism of resin composite build-up technique had considerable influence on contraction stress. Incremental buildup using composites with low elastic modulus did not reduce contraction stress intensity compared with bulk-cured techniques.     

Influence of Attachment Systems on Load Transfer of an Implant-Assisted Maxillary Overdenture

PURPOSE: This photoelastic study compared the load transfer characteristics of 2 retention mechanisms in an implant-assisted overdenture prosthesis. MATERIALS AND METHODS: Four implants were incorporated into a photoelastic model of a moderately resorbed edentulous human maxilla. Two retention mechanisms were studied by changing components on the same model and the palateless overdenture. The retention mechanisms studied were bar splint with anterior clip and distal resilient attachments, and solitary ball/O-ring attachments. Loads, ranging from 1.4 to 14.4 kg, were applied to the palatal incline of central incisors and buccal incline of premolars with and without balancing contacts. Stresses developed around all the implants under each loading condition were photographed in the field of a circular polariscope. RESULTS: With both retention mechanisms, protrusive and laterotrusive loads without balancing contacts caused instability of the overdenture, producing minimal stress around the implants in the supporting structure. High intensity stresses indicating intrusion of the posterior implants were noted when the bar/distal resilient attachment overdenture had balancing contacts for protrusive and laterotrusive loads. The posterior implants of ball/O-ring attachment overdenture exhibited high intensity stresses indicating not only intrusion, but also bending, when the occlusion was balanced. CONCLUSIONS: Balanced occlusion was required in both retention mechanisms for stability of the implant-assisted overdenture when clinically acceptable loads were applied. The protrusive and laterotrusive loads were not distributed equitably in either mechanism, since highest stresses occurred at the posterior implants.     

Portal vein thrombosis complicating hepatocellular carcinoma. Value of ultrasound-guided fine-needle biopsy of the thrombus in the therapeutic management

Abstract: During a 4-year period portal vein thrombosis was diagnosed in 20 Child class A patients with cirrhosis by means of ultrasound and ultrasound-Doppler study. Seventeen of them showed single or multiple focal liver lesions diagnosed as hepatocellular carcinoma by ultrasound-guided fine-needle biopsy and the remaining three a coarse liver echo-pattern without focal lesions. One patient was found to have developed portal vein thrombosis after the fifth ethanol injection of a single hepatocellular carcinoma lesion 17 mm in diameter. Ultrasound-guided fine-needle biopsy of the thrombus was performed on all the patients: portal vein thrombosis was neoplastic in 13 cases and non-neoplastic in seven cases (five patients with a single lesion; one with two lesions; one with coarse liver echo-pattern). Among the five patients with a single lesion, one had already been treated by percutaneous ethanol injection therapy. There were no complications related to the biopsy procedures. The diagnosis of non-neoplastic thrombosis allowed five new patients to be recruited for percutaneous ethanol injection treatment and allowed it to continue in the patient with portal vein thrombosis occurring after the fifth ethanol injection. The routine use of ultrasound-guided fine-needle biopsy of portal vein thrombosis yields an accurate diagnosis of the nature of the thrombus and can improve the selection for percutaneous ethanol injection treatment of patients with cirrhosis with hepatocellular carcinoma lesions.     

Sclerodermic linear lupus panniculitis: report of two cases

Lupus erythematosus panniculitis is a rare disease characterized by deep subcutaneous nodules, most commonly localized on the upper limbs and face. Unique clinical presentations, such as linear configuration or 'overlap' forms between lupus erythematosus panniculitis and localized scleroderma have been reported. We present here the clinical characteristics, course and laboratory findings of 2 patients having linear lupus erythematosus panniculitis with localized scleroderma-like changes. The 2 patients (of the 14 patients with lupus erythematosus panniculitis seen by us since 1990) were females with a young age at the onset of disease (median, 25 years). In 1 case, evolution into systemic lupus erythematosus with severe renal involvement occurred whereas the other patient, who had a spontaneous abortion and exhibited anticardiolipin antibodies, should be followed and screened for the emergence of antiphospholipid syndrome. Thus, the clinical behavior of this variant seems to be more aggressive, as compared with the usual course of lupus erythematosus panniculitis, which is considered to be a benign disease, although some reports have suggested that its prognosis is not always favorable. The linear distribution could be the clinical hallmark of such a unique, 'sclerodermic' subset of lupus erythematosus panniculitis.     

Neuropsychiatric symptoms in 921 elderly subjects with dementia: a comparison between vascular and neurodegenerative types

Objective: i) to describe the neuropsychiatric profile of elderly subjects with dementia by comparing vascular (VaD) and degenerative dementias, i.e. dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD); ii) to assess whether the severity and type of dementia are associated with clinically relevant neuropsychiatric symptoms (CR‐NPS). Method: One hundred and thirty‐one out‐patients with VaD, 100 with DLB and 690 with AD were studied. NPS were evaluated by the neuropsychiatric inventory (NPI). Results: Vascular dementia had lower total and domain‐specific NPI scores and a lower frequency of CR‐NPS than AD and DLB, for which frequency of CR‐NPS increased significantly with disease severity, particularly in AD. Logistic regression analysis showed that a higher CDR score and a diagnosis of degenerative dementia were independently associated with CR‐NPS. Conclusion: Vascular dementia is associated less with CR‐NPS than AD and DLB. Frequency of CR‐NPS increases with disease severity in AD and, to a lesser extent, in DLB.     

Deep brain stimulation in the treatment of severe dystonia

A retrospective study of a consecutive series of 19 patients with medically intractable dystonia treated with uni- or bilateral deep brain stimulation (DBS) is reported. A minimal follow-up of 6 months was available, up to eleven years in one patient. The first twelve consecutive patients (4 with primary and 8 with secondary dystonia) were treated with chronic stimulation of the posterior part of the ventrolateral thalamic nucleus (VLp). In this group global functional outcome was improved in 8 patients, although dystonia movement and disability scale scores did not show significant improvement. Of the 12 patients treated first by VLp DBS, three (1 primary and 2 secondary dystonia) underwent pallidal (GPi) DBS after the VLp DBS failed to improve their symptoms. The last seven consecutive patients (5 primary and 2 secondary dystonia) were treated directly with GPi DBS. Extracranial infection prevented chronic GPi DBS in one patient. In another GPi patient, preliminary negative tests with the electrodes discouraged implantation of the stimulators, and the patient was not treated with chronic DBS. In the remaining group of eight patients including those previously treated with VLp DBS, chronic GPi DBS resulted in a significant improvement in the dystonia movement scale and disability scores. Although this is a retrospective study dealing with dystonia of heterogeneous etiology, the results strongly suggest that GPi DBS has a better outcome than VLp DBS Received: 22 January 2001 / Received in revised form: 28 February 2001 / Accepted: 1 March 2001     

Aggregation of tau protein by aluminum

Aluminum has been detected in Alzheimer neurofibrillary tangles, but the significance of its presence is unknown. The principal component of tangles is the paired helical filament (PHF), comprised of tau protein. We investigated whether aluminum could induce tau protein to form filaments or aggregate. When 10 μM bovine tau or non-phosphorylated recombinant human tau was combined with 400 μM or more aluminum, tau protein appeared to aggregate, observed as a dose-dependent decrease in electrophoretic mobility on SDS-PAGE. Tau appeared as a smear above the region of the expected tau bands and, at higher aluminum,doses, failed to enter the gel. A tau fragment encompassing the microtubule binding domains did not show decreased mobility in the presence of aluminum, but did form aggregates that failed to electrophorese. However no fibrillar structures were observed in the aluminum-treated tau samples when observed by electron microscopy. The effect of aluminum on tau mobility was reversed by incubating with 1 mM deferoxamine. In contrast, the morphology of PHF fibrils was unaffected by deferoxamine treatment and the characteristic abnormal mobility of PHF-tau was not reduced by deferoxamine. This suggests that aluminum is not, by itself, a significant factor in maintaining the assembly of PHF-tau as fibrils or in its abnormal mobility on SDS gels. Aluminum treatment of 3T3 fibroblasts transfected with human tau resulted in toxicity, but did not change tau expression levels or induce tau aggregation. In conclusion, aluminum appears to induce isolated tau protein to aggregate in a phosphate-independent way, without the formation of fibrils. This effect was not observed when tau-transfected cells were treated with toxic doses of aluminum.