递增负荷有氧运动14周影响不同衰老程度老年男性的生物学年龄

目的:观察有氧运动对不同衰老程度老年男性生物学年龄的影响。方法:于2002-09/12选择上海市杨浦区退休老年男性13名,年龄59～76岁,平均(64±5)岁,近期无系统健身运动经历。13名老年男性采用功率自行车进行14周递增负荷有氧运动。以最大心率的75%所对应的运动负荷为训练强度;在第4,8周末重新确定运动强度,第5～8周、9～14周以新负荷作为健身运动负荷。每周3次,起始2周每次持续20min,以后每隔2周每次增加5min。采用刘继武等推荐的生物学年龄成套测试方法测定生物学年龄。运动前和运动后测定生物学年龄以及身体形态、心血管、肺功能等生理指标。并根据生物学年龄与实际年龄的差距,分成提前衰老组(生物学年龄大于实际年龄)和延缓衰老组(生物学年龄小于实际年龄)进行对照分析。结果:①老年男性运动前生物学年龄大于实际年龄,差异无显著性意义(P=0.56),有氧运动后生物学年龄小于实际年龄,差异无显著性意义(P=0.066),有氧运动后生物学年龄小于运动前,差异有非常显著性意义[分别为(65.13±6.33),(67.15±7.13)岁,P<0.01]。②根据生物学年龄与实际年龄的差距,将老年男性分成提前衰老组7名和延缓衰老组6名。提前衰老组老年男性有氧运动前生物学年龄大于实际年龄,递增负荷有氧运动后生物学年龄接近实际年龄,低于运动前,差异有非常显著性意义[分别为(69.00±6.73),(71.90±7.55)岁,P<0.01]。延缓衰老组有氧运动前生物学年龄小于实际年龄,有氧运动后生物学年龄进一步减少,低于运动前,差异无显著性意义(P>0.05)。③提前衰老组老年男性有氧运动后腰围低于运动前,腰臀比高于运动前,差异有显著性意义[分别为(94.20±5.14),(99.58±6.48)cm;(0.95±0.03),(0.92±0.04)cm,P<0.05]。延缓衰老组老年男性上臂皮褶厚度低于运动前,差异有显著性意义[分别为(11.00±2.17),(14.42±2.33)mm,P<0.05]。其他身体形态指标变化差异无显著性意义。生理功能指标变化较明显,最大摄氧量、闭眼单脚站立时间均高于运动前,差异有显著性意义[分别为(36.08±5.40),(30.08±2.21)mL/(kg·min);(28.17±20.51),(12.4±14.78)s,P<0.05]。④两组老年男性有氧运动后心血管和肺功能指标中收缩压、舒张压均有下降,肺活量增加。其中延缓衰老组老年男性肺活量高于运动前,差异有显著性意义[分别为(3.98±0.69),(3.61±0.71)L,P<0.05]。结论:有氧运动对不同衰老程度老年男性生物学年龄、身体形态和生理功能均可产生良性影响,达到延缓衰老目的。     

Apolipoprotein E isoform-dependent amyloid deposition and neuritic degeneration in a mouse model of Alzheimer's disease

Apolipoprotein E (apoE) alleles determine the age-adjusted relative risk (epsilon4 > epsilon3) for Alzheimer's disease (AD). ApoE may affect AD pathogenesis by promoting deposition of the amyloid-beta (Abeta) peptide and its conversion to a fibrillar form. To determine the effect of apoE on Abeta deposition and AD pathology, we compared APP(V717F) transgenic (TG) mice expressing mouse, human, or no apoE (apoE(-/-)). A severe, plaque-associated neuritic dystrophy developed in APP(V717F) TG mice expressing mouse or human apoE. Though significant levels of Abeta deposition also occurred in APP(V717F) TG, apoE(-/-) mice, neuritic degeneration was virtually absent. Expression of apoE3 and apoE4 in APP(V717F) TG, apoE(-/-) mice resulted in fibrillar Abeta deposits and neuritic plaques by 15 months of age and substantially (>10-fold) more fibrillar deposits were observed in apoE4-expressing APP(V717F) TG mice. Our data demonstrate a critical and isoform-specific role for apoE in neuritic plaque formation, a pathological hallmark of AD.     

Self-efficacy mediates walking performance in older adults with knee osteoarthritis

BACKGROUND: Self-efficacy is a determinant of walking performance in older adults with knee osteoarthritis. We examined whether self-efficacy mediated the effect of age, psychosocial, impairment, and mechanical factors on walking performance. METHODS: Fifty-four participants with knee osteoarthritis completed the Six Minute Walk test and Arthritis Self-Efficacy Scale. Independent variables reflected age, psychosocial (depressive symptoms), impairment (pain, stiffness), and mechanical (strength, obesity) factors. RESULTS: Self-efficacy fully mediated the effect of age and impairments on walking. The effects of strength were only partially mediated by self-efficacy. Depressive symptoms and obesity were not mediated by self-efficacy. CONCLUSIONS: These findings are consistent with Social Cognitive Theory, according to which age may alter outcome expectations, and impairments like pain and stiffness provide negative physiological feedback to influence performance. Mechanical factors like strength and obesity may better represent a person's capabilities and interact with other variables to influence physical performance in older adults with knee osteoarthritis.     

Plasma C-type natriuretic peptide forms and thyroid status in prepubertal children with acquired thyroid disease

Objective C‐type natriuretic peptide (CNP) and thyroid hormone (TH) are essential for normal skeletal growth. Plasma CNP peptides correlate with growth velocity, but the relationship between thyroid status and CNP production is unknown. This study examined the impact of restoring normal TH levels on CNP and height velocity (HV) in children with acquired hypo‐ and hyperthyroidism. Design We performed a prospective, observational study in prepubertal children with acquired hypothyroidism (n = 15) and hyperthyroidism (n = 12). Measurements Blood levels of CNP, amino‐terminal proCNP (NTproCNP), bone‐specific alkaline phosphatase (BSAP), IGF‐I and TH levels were measured before and during the first 6 months of standard treatment for hypo‐ and hyperthyroidism, and correlations were determined. Results At baseline, HV, CNP, NTproCNP and BSAP were significantly higher in hyper‐ than in hypothyroid subjects. Changes in TH after treatment were closely coupled to change in CNP and NTproCNP in hyperthyroid, but not in hypothyroid, children. In addition, a positive association of HV with CNP peptides was found during treatment of hyperthyroidism. Normalizing TH did not correlate with changes in BSAP or IGF‐I in either group. Conclusions Plasma CNP peptides are higher in children with hyperthyroidism than in those with hypothyroidism at diagnosis and, in hyperthyroid children, change concordantly with TH and HV during treatment. Differential responses of CNP in the two groups suggest CNP production is dependent on growth plate activity and not a direct effect of TH on CNP gene expression. Our findings suggest novel mechanisms underlying changes in skeletal response during treatment in children with acquired thyroid disease.     

C-type natriuretic peptide forms in adult hyperthyroidism: correlation with thyroid hormones and markers of bone turnover

Context Plasma C‐type natriuretic peptide (CNP) forms correlate with linear growth velocity in juveniles. In hyperthyroid children, plasma CNP products fall in parallel with height velocity and thyroid hormones (TH) as euthyroidism is restored. The effect of TH on CNP forms after completion of endochondral growth is unknown. Objective To determine the effect of restoring euthyroidism on plasma CNP forms and bone turnover markers (BTMs) in hyperthyroid adults. Design and setting We performed a prospective observational study in 20 adults (19 women) with acquired hyperthyroidism before and during carbimazole treatment. Intervention and main outcomes Blood levels of CNP, amino‐terminal propeptide of CNP (NTproCNP), TH and BTMs – bone‐specific alkaline phosphatase, osteocalcin, procollagen type 1 amino‐terminal propeptide and type 1 collagen C‐telopeptide (CTx) – were measured before and during the first 6 months of carbimazole treatment and correlations determined. Results Both CNP and NTproCNP were significantly correlated with TH at baseline. As in children, decreases in CNP forms were closely associated with fall in TH. Significant associations were found between CNP forms and CTx. Conclusions CNP production from tissues other than endochondral cartilage is responsive to TH. Strong temporal links with markers of bone resorption suggest that CNP may also participate in bone remodelling in the adult skeleton.     

Use of fecal occult blood test in hospitalized patients: Survey of physicians practicing in a large central Canadian health region and Canadian gastroenterologists

BACKGROUND:

Although the fecal occult blood test (FOBT) was developed for colorectal cancer screening in the outpatient setting, it continues to be used among hospitalized patients. No previous study has evaluated the knowledge, beliefs and attitudes of practicing physicians on the use of FOBT among hospitalized patients and compared practices among physicians with different medical specialty training.

OBJECTIVE:

To survey physicians in the Winnipeg Regional Health Authority (WRHA) and Canadian gastroenterologists (GIs) on the use of FOBT in hospitals.

METHODS:

A survey was distributed by e-mail to internists (n=198), emergency medicine (EM) physicians (n=118), general surgeons (n=47) and family medicine (FM) physicians with admitting privileges (n=29) in the WRHA. Canadian GIs were surveyed through the membership database of the Canadian Association of Gastroenterology (CAG) (n=449). The survey included items regarding demographics of the respondents and their current use of FOBT in hospitals.

RESULTS:

Response rates ranged from 18% among CAG members to 69% among FM physicians in the WRHA. General internal medicine, general surgeon and GI respondents were less likely to order a FOBT and less likely to believe that an FOBT was useful in assessing emergency room or hospitalized patients when compared with FM and EM respondents (P<0.001). The most common indications for ordering a FOBT were black stools and anemia with and without iron deficiency. Two-thirds of EM physicians preferred point-of-care testing rather than laboratory reporting of FOBT.

CONCLUSIONS:

The present survey suggests that FOBTs are commonly used in hospitals by EM and FM physicians for indications such as anemia and black stools.     

The place of high-dose BEAM therapy and autologous bone marrow transplantation in poor-risk Hodgkin's disease. A single-center eight- year study of 155 patients

Although high-dose chemotherapy and autologous bone marrow transplantation (ABMT) are increasingly being used for the treatment of relapsed and resistant Hodgkin's disease, there have been few large, single-center studies reported with adequate follow-up to allow full evaluation of this therapeutic modality. We present 155 poor-risk Hodgkin's disease patients who received high-dose BEAM (BCNU, etoposide, cytosine arabinoside, and melphalan) chemotherapy and ABMT who have been studied over a period of 8 years. All patients had either not attained a remission on mechlorethamine, vincristine, procarbazine, prednisone-type therapy and had poor prognostic features at presentation, not attained a complete remission or relapsed within 1 year of an initial alternating regimen, or not attained remission with two or more lines of treatment. At the time of ABMT the relapse status of the patients was as follows: 46 patients were primarily refractory to induction therapy, 7 were good partial responders, 52 were in first relapse, 37 in second relapse, and 13 in third relapse. Seventy-eight patients had chemoresistant disease, 33 had chemosensitive disease at the time of ABMT, and 44 were untested for chemosensitivity at latest relapse. The procedure related mortality in the first 90 days post-ABMT of 10% overall. At 3 months 43 patients (28%) were assessed as complete responders, 72 patients had a partial response (46%), and 24 patients (16%) had no response or progression of disease. However, by 6 months, 53 (24%) patients were assessed as complete responders and 51 (33%) patients had nonprogressive disease. Forty-five patients had received radiotherapy post-ABMT to residual masses (41 patients) or to previous sites of bulk disease (4 patients). The actuarial overall and progression-free survival at 5 years was 55% and 50%, respectively. On multivariate analysis patients with bulk (masses > 10 cm), heavily pretreated patients (those receiving three or more lines of treatment) and females had a significantly poorer prognosis. Relapse status was also significant for progression-free survival in that patients in second (60%) and third relapse (70%) had a better prognosis than those in first relapse (44%) or with primary refractory disease (33%). Response to prior chemotherapy did not predict for progression-free survival. These results enable comparisons to be made between high-dose chemotherapy with ABMT and conventional dose salvage therapy. Furthermore, although the results as a whole are highly encouraging, certain groups carry an unfavorable prognosis.