Alteration of Elastin, Collagen and their Cross-links in Abdominal Aortic Aneurysms

OBJECTIVES: although the mechanism of arterial dilation and aneurysm development has not been clarified, the degradation of elastin and collagen plays undoubtedly a critical role. We evaluated the elastin and collagen content through the detection of their cross-links in aneurysmal and non-aneurysmal abdominal aortic walls. MATERIALS AND METHODS: in 26 human abdominal aortic aneurysm specimens obtained during surgery and in 24 autopsy control samples of non-aneurysmal abdominal aorta the tissue content of elastin and collagen cross-links were measured by HPLC. Collagen was also detected by evaluating two characteristic amino acids, 4-hydroxyproline (4-hypro) with a colorimetric method and 5-hydroxylysine (5-hylys) by gas chromatography. RESULTS: significantly fewer elastin cross-links were found in aneurysm samples compared to controls (desmosines and isodesmosines: 90% reduction; p<0.01). The opposite was true for pyridinoline collagen cross-links (350% increase) and deoxypyridinolines (100% increase, p=0.01). Tissue content of 5-hylys, 4-hypro and total amino acids were reduced significantly by 50% in aneurysmal samples. CONCLUSIONS: beside confirming decreased elastin content in aneurysmal walls, these results show a concurrent increase of collagen cross-links. Since total collagen markers were decreased (decreased 4-hypro and 5-hylys) it is reasonable to suggest that in aneurysmal aortic walls old collagen accumulates cross-links while new collagen biosynthesis is somehow defective.     

Brachial Plexus Nerve Block Exhibits Prolonged Duration in the Elderly

Background: Upper limb trauma occurs frequently in elderly patients for whom peripheral nerve blocks are often preferred for anesthesia. The characteristics of such regional blocks have, however, never been described in an elderly population. Therefore, the authors assessed prospectively the onset and duration of upper extremity peripheral nerve block (the mid-humeral block) in elderly and young patients undergoing emergency upper extremity surgery.

Methods: Consecutive patients aged > 70 yr or < 70 yr received a mid-humeral block with a small volume of ropivacaine, 0.75%. Five milliliters was injected onto each of the musculocutaneous, radial, ulnar, and median nerves. Time to complete sensory and motor block and durations of complete sensory and motor block were assessed. Results are shown as median and its 95% confidence interval.

Results: Median ages were 77 yr (95% CI, 72-81 yr) and 39 yr (95% CI, 27-46 yr) in the two groups. Both groups had similar times to complete sensory blockade. The elderly group had longer durations of complete sensory (390 min [range, 280-435 min]vs. 150 min [range, 105-160 min];P < 0.05) and motor (357 min [range, 270-475 min]vs. 150 min [range, 90-210 min];P < 0.05) blockade. Duration of complete sensory block was significantly correlated with age ([rho] = 0.56;P < 0.05).     

Interleukin-3 dependent c-myc protein expression during the cell cycle of murine mast cells.

Aim of the study was to evaluate the relationship between the mitogenic stimulus interleukin-3 to normal murine mast cells and the cell cycle dependent expression of the nuclear c-myc protein. In order to do that on a cell by cell basis, we measured the nuclear c-myc protein simultaneously by flow cytometry, via specific monoclonal antibodies, and the DNA content via the intercalating dye propidium iodide. When cells were deprived from interleukin-3 (IL-3), proliferation was inhibited and the majority of cells arrested in early G1 (G1A, characterized by low c-myc content). Readdition of IL-3 resulted in a slow transition of cells from G1A to late G1 (G1B, at higher c-myc content) before DNA synthesis started. G1A cells with low c-myc content do not undertake DNA synthesis. Using a stathmokinetic methodology we confirmed that the G1A cells are early postmitotic G1 phase cells. The low content of c-myc within these cells appears a direct consequence of reduced c-myc levels during mitosis. Cumulatively, the data suggest that c-myc protein levels of murine mast cells fall at mitosis and that these levels must rise before cells can traverse the G1 phase. Our data are compatible with a model in which c-myc protein content of G1 phase cells has to reach a critical threshold before the cells can move further into the cell cycle.     

Mortality study of asbestos cement workers

The present study describes cause-specific mortality of asbestos cement workers in the Emilia Romagna region of Italy. The cohort included workers in ten factories, most of which started operating between 1955 and 1965. Asbestos, mainly chrysotile, constituted 10%–20% of the dry component of the mixture. Crocidolite range between 5% and 50% of total asbestos. Asbestos concentrations up to 44 ff/cc were reported prior to 1975, while in recent years they have usually been below 0–1 ff/cc. The cohort included 3341 workers who had at some time been employed in the ten factories under study. Their mortality experience was compared with that of the population resident in Emilia Romagna. Vital status was ascertained at 1989. Seventy-three subjects were lost to followup (2.2%). Mortality from all causes and from all types of cancer was increased in the cohort. Malignant neoplasms of the respiratory tract showed a significant increase (SMR: 134; 90% confidence interval: 101–175; 40 observed) due to lung cancer (SMR: 124; 90% confidence interval: 91–166; 33 observed) and neoplasms of the pleura, mediastinum, and other parts of the respiratory tract (SMR: 602; 90% confidence interval 237–1267; 5 observed). The discrepancy between observed and expected mortality mainly concerned subjects with at least 20 years of employment in the factories. Five more cases of histologically confirmed mesothelioma occurred after the end of follow-up.     

抗体阴性重症肌无力发病与凝集素之间关系研究

借助研究抗体阴性重症肌无力（ＭＧ）发病与凝集素之间的关系，以阐明其发病过程是否与凝集素有关。方法观察伴刀豆球蛋白Ａ（ＣｏｎＡ）和麦胚凝集素（Ｔｒｉｔｉｃｕｍ）及其凝集素－糖复合物对ＴＥ６７１细胞表达的乙酰胆碱受体（ＡＣｈＲ）功能的作用，以及对α－ＢｕＴｘ结合试验的影响。结果有两种凝集素对ＡＣｈＲ功能均有抑制作用，抑制率（％）分别为５４±１４（ｎ＝１１）和４７±１６（ｎ＝１０），此作用可被３种糖抑制，抑制率（％）分别为：９５±５（ｎ＝５）和８４±８（ｎ＝５）；６９±６（ｎ＝４）和６５±５（ｎ＝４）；３９±４（ｎ＝５）和５７±６（ｎ＝５）；ＣｏｎＡ抑制α－ＢｕＴｘ结合试验，而Ｔｒｉｔｉｃｕｍ则不能。结论Ｔｒｉｔｉｃｕｍ和抗体阴性ＭＧ患者非ＩｇＧ部分对ＡＣｈＲ功能和α－ＢｕＴｘ结合试验的作用类同或一致，表明抗体阴性ＭＧ患者非ＩｇＧ部分中的内源性Ｔｒｉｔｉｃｕｍ样糖蛋白在其发病过程中起重要作用。     

Comparing different methods for homocysteine determination.

Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods).     

Sirolimus and mycophenolate mofetil as calcineurin inhibitor-free immunosuppression in a cardiac transplant patient with chronic renal failure.

Chronic renal failure triggered by calcineurin inhibitor (CNI)-based immunosuppression is a common complication after cardiac transplantation. Sirolimus and mycophenolate mofetil (MMF) are 2 newer immunosuppressive agents with no documented nephrotoxic side effects. This case report describes a patient with ongoing chronic renal failure 10 months after cardiac transplantation on cyclosporine-based immunosuppressive therapy. Conversion of the immunosuppressive regimen from cyclosporine to sirolimus and MMF resulted in freedom from acute rejection, excellent cardiac graft function and consistently improved renal function. This case illustrates the beneficial potential of sirolimus and MMF as CNI-free and safe long-term immunosuppression in a patient with chronic renal failure after heart transplantation.     

Life events exposure before a treated major depressive episode depends on the number of past episodes.

A cross-sectional survey investigated the relationship between the number of previous depressive episodes and life events, testing the kindling hypothesis, in a sample of 13,377 treated patients with unipolar depression. A linear decline of average life events exposure is observed for more frequent past episodes, even when age, gender and severity are taken into account.