Cardiac troponin T and creatine kinase MB are not increased in exterior oblique muscle of patients with renal failure

BACKGROUND

Serum cardiac troponin T (cTnT) concentrations may be increased in patients with renal dysfunction without evidence of cardiac damage, as assessed by conventional methods. It has been suggested that these positive measurements result from the expression in skeletal muscle of fetal isoforms of cTnT, which are detected by the cTnT immunoassay.

METHODS

Skeletal muscle (exterior oblique) biopsies were taken from healthy living kidney donors (n = 5) and transplant recipients (n = 19). The amounts of cTnT and creatine kinase (CK) isoenzymes in skeletal muscle of healthy controls were compared with those in patients with renal failure (Wilcoxon-Mann-Whitney test). cTnT was measured quantitatively by a second-generation assay, with a limit of detection of 1 microg/g of protein, and qualitatively by immunohistochemistry and immunoblotting. CK-MB was measured by quantitative electrophoresis.

RESULTS

Minute quantities of cTnT were detected in 2 of the 5 (40%) control samples and 9 of the 19 (47%) renal failure samples, respectively, at mean concentrations of <5 microg/g of protein for both subject groups. This was <1/6000th that found in heart muscle. There was no significant difference in cTnT or CK-MB content in skeletal muscle between healthy controls and patients with renal failure. Increased serum cTnT did not predict detectable cTnT in skeletal muscle. cTnT was not detected qualitatively by immunoblotting or immunohistochemistry in any skeletal muscle samples.

CONCLUSIONS

Uremia does not affect the content of cTnT or CK-MB in exterior oblique muscle, suggesting that cTnT detected in serum from patients with renal failure does not originate from skeletal muscle.

Caspase cleavage of vimentin disrupts intermediate filaments and promotes apoptosis

Caspases are key mediators of apoptosis. Using a novel expression cloning strategy we recently developed to identify cDNAs encoding caspase substrates, we isolated the intermediate filament protein vimentin as a caspase substrate. Vimentin is preferentially cleaved by multiple caspases at distinct sites in vitro, including Asp85 by caspases-3 and -7 and Asp259 by caspase-6, to yield multiple proteolytic fragments. Vimentin is rapidly proteolyzed by multiple caspases into similar sized fragments during apoptosis induced by many stimuli. Caspase cleavage of vimentin disrupts its cytoplasmic network of intermediate filaments and coincides temporally with nuclear fragmentation. Moreover, caspase proteolysis of vimentin at Asp85 generates a pro-apoptotic amino-terminal fragment whose ability to induce apoptosis is dependent on caspases. Taken together, our findings suggest that caspase proteolysis of vimentin promotes apoptosis by dismantling intermediate filaments and by amplifying the cell death signal via a pro-apoptotic cleavage product.

xPitx1 plays a role in specifying cement gland and head during early Xenopus development

Xenopus Pitx1 is a homeobox gene whose family members are structurally and functionally conserved in organisms as diverse as Drosophila, chick, mouse, human, and frog. Present as a maternal transcript, the gene is zygotically expressed during gastrulation in a dorsal streak of cells. This streak restricts to a small circular domain underlying the center of presumptive neural plate. Shortly thereafter, a crescent of expression develops at the border of anterior neural ectoderm, and as the central plate domain diminishes, the crescent coalesces to define the presumptive cement gland. Expression remains high throughout cement gland development, and subsequently expands to include ectodermal cells involved in stomodeal invagination. During early organogenesis, expression ensues in developing eye, posterior lateral mesoderm, and first branchial arch derivatives. Ectopic expression of xPitx1 causes head deformities including enlarged cement gland, ectopic cement glands, and posterior deformities or, in extreme cases, inhibition of recognizable structures posterior to the cement gland. Expression of markers such as XCG-1, xOtx2, xPax6, neuralbeta tubulin, and xTwist suggest that increases in cement gland and lower mandibular size are likely at the expense of other head tissues. Paradoxically, overexpression is sufficient to partially rescue embryos that are axially perturbed by ultraviolet irradiation or retinoic acid administration. Ectopic expression of xPitx1 in ectodermal explants directly promotes cement gland development as there was no evidence that mesodermal or neural tissue was present in explants.

Daily catheter-directed single dosing of t-PA in treatment of acute deep venous thrombosis of the lower extremity

The strong fibrin affinity of recombinant tissue plasminogen activator (rt-PA) theoretically obviates continuous infusion or replacement of t-PA after direct intrathrombic injection. This hypothesis led the authors to evaluate single daily catheter-directed injection of rt-PA as a thrombolytic treatment for acute deep vein thrombosis of the lower extremity. Once-daily injection of rt-PA was performed in large thrombosed veins (popliteal or larger) with use of pulse-spray catheters and in small thrombosed veins in patients' calves with use of 3-4-F coaxial catheters. Patients received only full systemic anticoagulation on his/her patient care unit. This dosing regimen has been tested in 10 patients (12 legs) with a maximum dose of 50 mg per leg per day. Extensive thrombolysis was achieved in nine patients and partial thrombolysis was achieved in one patient, at an average total dose of 106 mg of rt-PA per leg. Minor bleeding was seen in three patients and no transfusions were needed. Our technique and the rationale for this pilot study is the focus of this article.

Survival of conditionally immortalized hepatocytes in the spleen of syngeneic rats

BACKGROUND

Hepatocyte transplantation has been shown to be effective in the treatment of liver failure; however, the shortage of donor organs limits its clinical application. Several reports have suggested that conditionally immortalized hepatocytes (CIH) could be an alternative to primary hepatocytes. However, CIH are known to undergo apoptosis in vitro at a non-permissive temperature, which is similar to body temperature.

METHODS

To investigate the duration of survival and in vivo apoptosis of CIH in the syngeneic host, the L2A2 cells (a kind of CIH) that were established from hepatocytes of a Lewis rat with a gene for a temperature-sensitive Simian Virus 40 (SV40) large T antigen were transplanted into the spleen. Cells were isolated from the spleen that was removed periodically up to 6 months, and used to detect the presence of the L2A2 cells among them with the selective culture for CIH and T-antigen PCR. In situ apoptosis of L2A2 cells was also examined. In order to improve the survival of transplanted L2A2 cells in the host, a group of rats were partially hepatectomized 1 day before transplantation was performed.

RESULTS

The L2A2 cells secreted albumin at a rate of 1.17 +/- 0.18 microg/24 h per 10(6) cells in vitro. After transplantation, L2A2 cell colonies and PCR amplification bands appeared up to 14 and 7 days, respectively, but this duration was not prolonged by a partial hepatectomy. The spleen showed a large number of hepatocytes that were in the process of dying on the 5th day, and only a number of ghost hepatocytes were present on the 7th day of transplantation. No tumors were found during the 6-month observation period.

CONCLUSIONS

Conditionally immortalized hepatocytes can survive in the spleen for a limited period, in spite of the growth stimulation, most likely because they undergo apoptosis in vivo as well as in vitro at a non-permissive temperature. These data suggest that the use of these cells in hepatocyte transplantation be limited to temporary hepatic support.

The incidence and clinical characteristics of symptomatic propylthiouracil-induced hepatic injury in patients with hyperthyroidism: a single-center retrospective study

OBJECTIVES

Although symptomatic propylthiouracil (PTU)-induced hepatic injury is known to be rare, there have been few reports about its exact incidence in patients with hyperthyroidism. We tried to evaluate its incidence in a single center and its clinical course.

METHODS

Medical records of 912 hyperthyroid patients who had been diagnosed between March 1990 and December 1998 were reviewed about clinical characteristics, management, and laboratory findings. Symptomatic PTU-induced hepatic injury was defined as the development of jaundice or hepatitis symptoms with at least a 3-times elevation of liver function tests (LFT) without other causes.

RESULTS

Four hundred ninety-seven patients (age 42.6 +/- 10.7 yr, male/female 140/357) were included. Clinically overt hepatitis developed in six patients (1.2%; age, 43.7 +/- 14.8 yr; male:female ratio, 3:3) between 12 and 49 days after PTU administration. Jaundice and itching developed in five patients, fever in two, rash in two, and arthralgia in one. Bilirubin, ALT, and ALP increased in five, four, and six patients, respectively (293 +/- 288 micromol/L, 143 +/- 111 U/L, and 265 +/- 81 U/L; normal, < 117 U/L). The type of hepatic injury was cholestatic in three, hepatocellular in one, and mixed in two patients. None resulted from viral hepatitis. There were no statistical differences in age, sex, PTU dose, or T4 and T3 levels at initial diagnosis between patients with and without hepatic injury. LFT normalized in all patients between 16 and 145 (72.8 +/- 46.4) days after the PTU withdrawal.

CONCLUSIONS

Symptomatic hepatic injury develops usually within the first few months of PTU administration with rare frequency, but its clinical course is relatively benign once the drug is withdrawn. However, it may be difficult to predict its development, so all patients should be monitored for rise in LFTs at regular intervals, especially during the early period.

Production of recombinant human type I procollagen trimers using a four-gene expression system in the yeast Saccharomyces cerevisiae

The expression of stable recombinant human collagen requires an expression system capable of post-translational modifications and assembly of the procollagen polypeptides. Two genes were expressed in the yeast Saccharomyces cerevisiae to produce both propeptide chains that constitute human type I procollagen. Two additional genes were expressed coding for the subunits of prolyl hydroxylase, an enzyme that post-translationally modifies procollagen and that confers heat (thermal) stability to the triple helical conformation of the collagen molecule. Type I procollagen was produced as a stable heterotrimeric helix similar to type I procollagen produced in tissue culture. A key requirement for glutamate was identified as a medium supplement to obtain high expression levels of type I procollagen as heat-stable heterotrimers in Saccharomyces. Expression of these four genes was sufficient for correct assembly and processing of type I procollagen in a eucaryotic system that does not produce collagen.

Decreased trabecular bone mineral density in newly diagnosed inflammatory bowel disease patients in Korea

BACKGROUND

Decreased bone mineral density (BMD) is common in Western patients with inflammatory bowel disease (IBD). However, BMD has never been studied in Asia where the demographic and socio-economic status are different from the West. The aim of this study was to investigate the prevalence and mechanisms of osteopenia in newly diagnosed Korean patients with IBD.

METHODS

We studied 14 patients with Crohn's disease (CD) and 25 patients with ulcerative colitis (UC), all of whom had never been treated with corticosteroids. Bone mineral density was measured in the lumbar spine and the femoral neck by dual energy X-ray absorptiometry. Biochemical parameters including serum osteocalcin, parathyroid hormone, plasma inactive and active vitamin D, and urinary deoxypyridinoline were measured.

RESULTS

The BMD Z score at the lumbar spine was lower both in CD and in UC patients, but there was no significant difference between the two groups. There was no significant difference in nutritional status or biochemical parameters of bone metabolism between patients with a normal BMD and those with a decreased BMD.

CONCLUSIONS

Low BMD at the lumbar spine is common in newly diagnosed Korean patients with IBD, a result which is similar to Western studies. The mechanism for low bone mass remains undetermined; however, nutritional status and hormonal parameters of bone metabolism, and ethnic differences are not likely to be an important factor in the pathogenesis of this bone loss.

Dedifferentiation of conditionally immortalized hepatocytes with long-term in vitro passage

The rat hepatocytes were immortalized using a temperature-sensitive mutant of SV40 large T antigen (tsT) to develop as a possible substitute for primary hepatocytes. Four rat hepatocyte lines that have been developed and maintained more than passage 50, were characterized for their cellular morphology, T antigen and p53 expression, chromosomes, liver-specific differentiation, telomerase activity and anchorage independent growth. All of four cell lines showed a typical epithelial cell morphology, but the population-doubling time became short with passage: 18 to 60%. T antigen expression was increased with passage about 3 to 65 times at permissive temperature but decreased significantly at non-permissive temperature. The expression level of p53 unchanged during passages was also decreased at non-permissive temperature. The distribution of chromosome number changed somewhat with passage. The production levels of albumin and urea in four cell lines were 2.4 to 13.0% and 7.5 to 19.9% of those produced in primary hepatocytes, respectively and were decreased to an undetectable level with passage. Telomerase activity was increased 10 fold following immortalization of cells, but anchorage independent growth of cells did not develop. These results indicate that conditionally immortalized hepatocytes become dedifferentiated with in vitro passage, which may be caused by marked chromosomal damages that occur with compulsive and continuous replications by the increment of T antigen content with passage and its sequential inhibition of p53 function.

CT via percutaneous splenoportography: experiment and application

OBJECTIVE

To introduce computed tomography via percutaneous splenoportography (CTSP), a new method for determining hepatic diseases.

METHODS

Ten hybrid dogs and 31 patients with primary hepatic cancer (PHC) were included in the study. Each dog was examined by CT, computed tomography via arterial portography (CTAP), and CTSP to compare the enhanced density of the liver. The 31 patients were examined by CTSP and the appearance of PHC was compared with their pathological results to evaluate the diagnostic significance of CTSP.

RESULTS

The animal experiment showed that both CTAP and CTSP could obviously enhance the density of the liver (P < 0.01), but no significant difference was observed in the enhanced densities between the two methods (P > 0.05). On the CTSP images of the 31 patients, the density of the livers was increased to 168-192 Hu, whereas the density of the cancers was as low as that on the images of CT scans (< 58 Hu). The CTSP findings were consistent with the surgical ones from space occupying lesions. The diagnostic value of CTSP was obviously superior to that of general enhanced CT. However, it was difficult for CTSP to show nodules less than 1 cm in size located on the surface of the liver or the hepatic portal zone.

CONCLUSIONS

Like CTAP, CTSP is also a sensitive method for showing occupant in the liver. But the equipments and the procedures are simpler for CTSP than for CTAP. CTSP is an alternative procedure in clinical practice.

An automated form of video image analysis applied to classification of movement disorders

Video image analysis is able to provide quantitative data on postural and movement abnormalities and thus has an important application in neurological diagnosis and management. The conventional techniques require patients to be videotaped while wearing markers in a highly structured laboratory environment. This restricts the utility of video in routine clinical practise. We have begun development of intelligent software which aims to provide a more flexible system able to quantify human posture and movement directly from whole-body images without markers and in an unstructured environment. The steps involved are to extract complete human profiles from video frames, to fit skeletal frameworks to the profiles and derive joint angles and swing distances. By this means a given posture is reduced to a set of basic parameters that can provide input to a neural network classifier. To test the system's performance we videotaped patients with dopa-responsive Parkinsonism and age-matched normals during several gait cycles, to yield 61 patient and 49 normal postures. These postures were reduced to their basic parameters and fed to the neural network classifier in various combinations. The optimal parameter sets (consisting of both swing distances and joint angles) yielded successful classification of normals and patients with an accuracy above 90%. This result demonstrated the feasibility of the approach. The technique has the potential to guide clinicians on the relative sensitivity of specific postural/gait features in diagnosis. Future studies will aim to improve the robustness of the system in providing accurate parameter estimates from subjects wearing a range of clothing, and to further improve discrimination by incorporating more stages of the gait cycle into the analysis.

Thrombolytic therapy for deep venous thrombosis?

We present the case of a man bedridden by deep venous thrombosis who was given intraclot instillations of recombinant tissue plasminogen activator with remarkable improvement. Although such aggressive treatment may be justified in severe cases, the role for thrombolytic agents for less symptomatic deep venous thrombosis is undefined. We discuss the question of when thrombolytic therapy should be considered. However, proper clinical trials are needed before firm recommendations can be made.

Gadolinium-enhanced 3D MRA prior to isolated hepatic perfusion for metastases

PURPOSE

Isolated hepatic perfusion (IHP) is a new treatment for patients with isolated unresectable liver metastases, which can result in a partial or complete response in approximately 75% of patients. Preoperative knowledge of hepatic arterial anatomy is important to adequately perfuse the liver. Digital subtraction angiography (DSA) is currently used to identify the hepatic arterial anatomy. The purpose of this study was to determine if MR angiography (MRA) could replace DSA prior to IHP.

METHOD

Twenty-seven patients scheduled to undergo IHP underwent MRA with a contrast-enhanced 3D time-of-flight gradient echo sequence. Both maximal intensity projections (MIPs) and source coronal images were used to evaluate the images. The results of the MRA were interpreted by two readers who were blinded to the surgical results. The first 17 patients also underwent DSA, and a separate comparison was made with those results. Anatomy was characterized as either normal hepatic arteries (NHAs), normal vasculature with an accessory left hepatic artery (aLHA), or a replaced right hepatic artery (rRHA).

RESULTS

MRA correctly detected all 22 patients with NHAs but also identified 6 aLHAs, of which only 2 were confirmed surgically. MRA correctly detected all five rRHAs. MIP images alone accurately depicted the hepatic arterial anatomy in only 9 of 27 (33%), usually because significant vessels were not visualized or their origin could not be determined. Source coronal images were required to accurately determine the anatomy in all patients. Among the 17 patients who underwent DSA, MRA detected 14 of 14 with NHA and 3 of 3 with rRHA. Six aLHAs were identified by MRA and five were confirmed by DSA.

CONCLUSION

Enhanced 3D MRA is an accurate method of depicting the hepatic arterial supply. In comparison to surgery, MRA overestimates the number of aLHAs, but this may be because these small vessels are not detected at surgery. Based on the results of this study, DSA has been replaced by MRA in the planning of IHP at our institution. A better display of MRA images is needed as MIP images were usually insensitive for the small caliber arteries supplying the liver.

Modeling Mercury Removal by Sorbent Injection

Sorbents for removing mercury from flue gases of coal-fired power plants are presently being evaluated due to potential regulation of mercury emissions under Title III of the 1990 Clean Air Act Amendments. Laboratory tests have been conducted to evaluate the adsorption characteristics of potential sorbents and the effects of flue gas constituents on these characteristics. This paper presents a theoretical model that combines the adsorption characteristics measured in the lab with mass transfer considerations to predict mercury removal by the duct injection process in actual flue gas streams. The model was used to determine the effect of various sorbent properties on mercury removal when injecting a powdered sorbent upstream of either an electrostatic precipitator (ESP) or fabric filter. Mercury removal is expected to differ between these configurations since the mass transfer conditions are different in an ESP and fabric filter. The model was used to determine when mercury removal is limited by mass transfer and when it is limited by sorbent capacity. This information defines conditions when removal can be improved by reducing particle size or increasing sorbent capacity. In both cases, removal can be increased by injecting more sorbent.

Ultrastructure of phospholipid mixtures reconstituted with surfactant proteins B and D

Surfactant protein (SP)-D is secreted from pulmonary alveolar type II cells into the alveolar lumen where potential interactions with surfactant lipids might occur. SP-D binds phosphatidylinositol (PI), a component of mammalian surfactants that is increased in a variety of injury states. We investigated the ultrastructure and properties of lipid protein recombinants that included SP-D, PI, and SP-B and compared these with recombinants based on SP-A. SP-D had a profound effect on the organization of phospholipid vesicles containing PI and SP-B, promoting the formation of atypical but highly ordered and surface-active tubular aggregates distinct in their dimensions and shape from the classical tubular myelin formed by SP-A. We also found both types of tubules in the secretions of type II cells maintained in long-term culture. These results suggest that surface atypical tubules can be formed with SP-D in vitro and in vivo.

[Mite-induced interleukin-5 and interleukin-4 expressions in peripheral blood mononuclear cells from asthmatic children with respiratory syncytial virus infection]

OBJECTIVE

To investigate the effects of respiratory syncytial virus(RSV) infection on mite-induced interleukin-5 and interleukin-4 expressions in cultures of PBMC from asthmatic children and their correlation with asthmatic symptoms.

METHODS

IL-5 and IL-4 expressions in mite (D. Pteronyssinus)-stimulated PBMC were assessed ex vivo by ELISA and reverse transcription-polymerase chain reaction (RT-PCR) in 16 allergic asthmatic children with RSV infection(A) and 14 patients without RSV infection(B), as well as 10 normal controls(C) (5.1 +/- 2.4 yrs). Meanwhile their correlation with serum ECP or current wheezing was analysed in patients after RSV infection.

RESULTS

(1) Stimulation of PBMC with mite antigens induced significantly higher IL-4 (34 +/- 24) ng/L vs (8 +/- 5) ng/L, (P < 0.01) and IL-5 (26 +/- 15) ng/L vs (6 +/- 5) ng/L release in allergic patients(B) as compared with healthy controls(C). The release was in a mite dose-dependent manner. Meanwhile, IL-5 level in group A (A) was the highest (73 +/- 47) ng/L, P < 0.05 compared with (B)). Similar results were obtained with IL-5 mRNA expressions. (2) Serum ECP level was significantly higher in group A (73 +/- 47) micrograms/L than in group C (18 +/- 12) micrograms/L, P < 0.01. There was a significant correlation between IL-5 release and ECP levels (r = 0.49, P < 0.05). (3) Mite-induced IL-5 release in PBMC was significantly increased in the group with wheezing symptom (71 +/- 40) ng/L compared with the asymptomatic group (34 +/- 29) ng/L, (P < 0.05).

CONCLUSIONS

Our findings indicated that during RSV infection, mite-induced IL-5 expression in PBMC of asthmatic children was up-regulated, which may enhance activation of eosinophils and precipitate or exacerbate asthma symptoms.