Flexible tantalum stents implanted in aortas and iliac arteries: effects in normal canines

Vascular endoprostheses made of knitted tantalum wire and expanded over angioplasty balloons were placed into aortas or iliac arteries of 14 normal dogs. Twelve stents were placed into the infrarenal abdominal aorta and two stents in the left common iliac arteries by the left carotid artery approach. To firmly expand the stent against the vascular wall, nominal stent sizes 0.5-1.0 mm larger than the measured arterial diameter were required. Arteriography performed at specified follow-up intervals showed no evidence of thrombi or emboli; all side branches (lumbar arteries) covered by the stents remained patent. Vascular diameter decreased minimally at 8 and 26 weeks, associated with histopathologic evidence of neointimal buildup. This buildup was highest at 8 weeks (mean, 313 microns) and was slightly less at 26 weeks (mean, 223 microns). Almost complete coverage by endothelium was seen as early as 3 weeks. It is concluded that the flexible tantalum wire stents are well tolerated by the arterial wall and become quickly endothelialized. No excessive neointimal buildup was observed during the 6-month study.     

Seroprevalence of human T-lymphotropic virus, hepatitis C virus, and human immunodeficiency virus in Asian American potential bone marrow donors

BACKGROUND: Asian Americans are generally underrepresented both as volunteer blood and bone marrow donors. STUDY DESIGN AND METHODS: To investigate the risk of transfusion transmission of viruses that is associated with increasing participation by Asian American donors, antibodies to human T-lymphotropic virus (HTLV), hepatitis C, and human immunodeficiency virus in Asian American volunteers recruited as potential bone marrow donors were measured. A total of 1354 Asian Americans were enrolled in the study, of whom 54 percent were Chinese, 26 percent Japanese, 9 percent Filipino, 4 percent Korean, 3 percent Indian, and 5 percent of other Asian or mixed Asian and other ethnicity. The majority of the study population was aged 20 through 49 and of high socioeconomic status, as indicated by education and income. Viral antibodies were measured with both screening enzyme-linked immunosorbent assays and supplemental testing, and polymerase chain reaction was used to resolve discrepant HTLV results. RESULTS: Confirmed seroprevalence rates for HTLV were 0.15 percent with one manufacturer's Western blot and 0.3 percent with the other; however, no sample was positive for HTLV types I or II in polymerase chain reaction. Confirmed seroprevalence to hepatitis C virus was 0.5 percent. No subject was seropositive for human immunodeficiency virus. CONCLUSION: On the basis of the moderate size and high education level of this study population, it is concluded that Asian American volunteer bone marrow donors do not pose a greater risk for transmission of HTLV type I or II, human immunodeficiency virus, or hepatitis C virus than does the average American blood donor.     

Long-term use of antecubital veins for plasma exchange. The Canadian Cooperative Multiple Sclerosis Study Group

True or sham plasma exchange was done weekly for 20 weeks in patients in two of the randomization groups in a prospective, blind clinical trial of experimental treatments for multiple sclerosis. Because patients could be randomized to receive sham plasma exchange and placebo medications, it was decided when the trial was designed that the use of fistulae, arteriovenous shunts, venous cutdowns, or other aggressive forms of venous access would not be permitted for any patient. Accordingly, patients judged to have inadequate superficial antecubital veins were ineligible for the trial. To date, only 13 (4.4%) of 294 patients considered for entry into the trial have been rejected on these grounds. In only 4 of the 93 patients undergoing exchange was it necessary to discontinue plasma exchange because of inadequate venous access. In 79.3 percent of the 1207 exchanges done in these patients, there were no problems of any kind with venous access. In 5.4 percent of these 1207 exchanges, it was necessary to terminate the procedure prematurely because of difficulties with patients' veins. Thus, the great majority of patients free of serious systemic illness (other than chronic progressive multiple sclerosis) can undergo weekly plasma exchange for up to 20 weeks using superficial antecubital veins without the need to resort to more invasive methods of venous access.     

La nécrosectomie transgastrique

La nécrosectomie transgastrique semble être une alternative présentant peu de risques de traitement pour les patients gravement atteints. Cependant, il manque à ce jour, une analyse des risques du procédé sur un nombre suffisant de patients; il est urgent de procéder à des collectes de données multicentriques. Il s’agit de procédés endoscopiques complexes, qui nécessitent une grande expérience, et le traitement de chaque patient devrait être planifié de fa?on interdisciplinaire en collaboration avec le chirurgien. Ce procédé devrait par conséquent rester limité aux centres spécialisés.     

The novel nomogram of Gleason sum upgrade: Possible application for the eligible criteria of low dose rate brachytherapy

Objective: To examine the rate of Gleason sum upgrading (GSU) from a sum of 6 to a Gleason sum of ≥7 in patients undergoing radical prostatectomy (RP), who fulfilled the recommendations for low dose rate brachytherapy (Gleason sum 6, prostate‐specific antigen ≤10 ng/mL, clinical stage ≤T2a and prostate volume ≤50 mL), and to test the performance of an existing nomogram for prediction of GSU in this specific cohort of patients. Methods: The analysis focused on 414 patients, who fulfilled the European Society for Therapeutic Radiation and Oncology and American Brachytherapy Society criteria for low dose rate brachytherapy (LD‐BT) and underwent a 10‐core prostate biopsy followed by RP. The rate of GSU was tabulated and the ability of available clinical and pathological parameters for predicting GSU was tested. Finally, the performance of an existing GSU nomogram was explored. Results: The overall rate of GSU was 35.5%. When applied to LD‐BT candidates, the existing nomogram was 65.8% accurate versus 70.8% for the new nomogram. In decision curve analysis tests, the new nomogram fared substantially better than the assumption that no patient is upgraded and better than the existing nomogram. Conclusions: GSU represents an important issue in LD‐BT candidates. The new nomogram might improve patient selection for LD‐BT and cancer control outcome by excluding patients with an elevated probability of GSU.     

Mechanism of asynchronous Ca2+ waves underlying agonist-induced contraction in the rat basilar artery

Background and purpose:

Uridine 5''-triphosphate (UTP) is a potent vasoconstrictor of cerebral arteries and induces Ca²⁺ waves in vascular smooth muscle cells (VSMCs). This study aimed to determine the mechanisms underlying UTP-induced Ca²⁺ waves in VSMCs of the rat basilar artery.

Experimental approach:

Isometric force and intracellular Ca²⁺ ([Ca²⁺]_i) were measured in endothelium-denuded rat basilar artery using wire myography and confocal microscopy respectively.

Key results:

Uridine 5''-triphosphate (0.1–1000 µmol·L⁻¹) concentration-dependently induced tonic contraction (pEC₅₀ = 4.34 ± 0.13), associated with sustained repetitive oscillations in [Ca²⁺]_i propagating along the length of the VSMCs as asynchronized Ca²⁺ waves. Inhibition of Ca²⁺ reuptake in sarcoplasmic reticulum (SR) by cyclopiazonic acid abolished the Ca²⁺ waves and resulted in a dramatic drop in tonic contraction. Nifedipine reduced the frequency of Ca²⁺ waves by 40% and tonic contraction by 52%, and the nifedipine-insensitive component was abolished by SKF-96365, an inhibitor of receptor- and store-operated channels, and KB-R7943, an inhibitor of reverse-mode Na⁺/Ca²⁺ exchange. Ongoing Ca²⁺ waves and tonic contraction were also abolished after blockade of inositol-1,4,5-triphosphate-sensitive receptors by 2-aminoethoxydiphenylborate, but not by high concentrations of ryanodine or tetracaine. However, depletion of ryanodine-sensitive SR Ca²⁺ stores prior to UTP stimulation prevented Ca²⁺ waves.

Conclusions and implications:

Uridine 5''-triphosphate-induced Ca²⁺ waves may underlie tonic contraction and appear to be produced by repetitive cycles of regenerative Ca²⁺ release from the SR through inositol-1,4,5-triphosphate-sensitive receptors. Maintenance of Ca²⁺ waves requires SR Ca²⁺ reuptake from Ca²⁺ entry across the plasma membrane via L-type Ca²⁺ channels, receptor- and store-operated channels, and reverse-mode Na⁺/Ca²⁺ exchange.     

Dynamic maps: a visual-analytic methodology for exploring spatio-temporal disease patterns

Background  

Epidemiologic studies are often confounded by the human and environmental interactions that are complex and dynamic spatio-temporal processes. Hence, it is difficult to discover nuances in the data and generate pertinent hypotheses. Dynamic mapping, a method to simultaneously visualize temporal and spatial information, was introduced to elucidate such complexities. A conceptual framework for dynamic mapping regarding principles and implementation methods was proposed.     

Abnormal liver function tests associated with severe rhabdomyolysis

Rhabdomyolysis is a syndrome of skeletal muscle injury with release of cellular constituents such as potassium,phosphate,urate and intracellular proteins such as myoglobin into the circulation,which may cause complications including acute kidney injury,electrolyte disturbance and cardiac instability.Abnormal liver function tests are frequently observed in cases of severe rhabdomyolysis.Typically,there is an increase in serum aminotransferases,namely aspartate aminotransferase and alanine aminotransferase.This raises the question of liver injury and often triggers a pathway of investigation which may lead to a liver biopsy.However,muscle can also be a source of the increased aminotransferase activity.This review discusses the dilemma of finding abnormal liver function tests in the setting of muscle injury and the potential implications of such an association.It delves into some of the clinical and experimental evidence for correlating muscle injury to raised aminotransferases,and discusses pathophysiological mechanisms such as oxidative stress which may cause actual liver injury.Serum aminotransferases lack tissue specificity to allow clinicians to distinguish primary liver injury from muscle injury.This review also explores potential approaches to improve the accuracy of our diagnostic tools,so that excessive or unnecessary liver investigations can be avoided.