Showing papers by "Texas Medical Center published in 2003"

Bivalirudin and Provisional Glycoprotein IIb/IIIa Blockade Compared With Heparin and Planned Glycoprotein IIb/IIIa Blockade During Percutaneous Coronary Intervention: REPLACE-2 Randomized Trial

Abstract: ContextThe direct thrombin inhibitor bivalirudin has been associated with better efficacy and less bleeding than heparin during coronary balloon angioplasty but has not been widely tested during contemporary percutaneous coronary intervention (PCI).ObjectiveTo determine the efficacy of bivalirudin, with glycoprotein IIb/IIIa (Gp IIb/IIIa) inhibition on a provisional basis for complications during PCI, compared with heparin plus planned Gp IIb/IIIa blockade with regard to protection from periprocedural ischemic and hemorrhagic complications.Design, Setting, and ParticipantsThe Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE)–2 trial, a randomized, double-blind, active-controlled trial conducted among 6010 patients undergoing urgent or elective PCI at 233 community or referral hospitals in 9 countries from October 2001 through August 2002.InterventionsPatients were randomly assigned to receive intravenous bivalirudin (0.75-mg/kg bolus plus 1.75 mg/kg per hour for the duration of PCI), with provisional Gp IIb/IIIa inhibition (n = 2999), or heparin (65-U/kg bolus) with planned Gp IIb/IIIa inhibition (abciximab or eptifibatide) (n = 3011). Both groups received daily aspirin and a thienopyridine for at least 30 days after PCI.Main Outcome MeasuresThe primary composite end point was 30-day incidence of death, myocardial infarction, urgent repeat revascularization, or in-hospital major bleeding; the secondary composite end point was 30-day incidence of death, myocardial infarction, or urgent repeat revascularization.ResultsProvisional Gp IIb/IIIa blockade was administered to 7.2% of patients in the bivalirudin group. By 30 days, the primary composite end point had occurred among 9.2% of patients in the bivalirudin group vs 10.0% of patients in the heparin-plus-Gp IIb/IIIa group (odds ratio, 0.92; 95% confidence interval, 0.77-1.09; P = .32). The secondary composite end point occurred in 7.6% of patients in the bivalirudin vs 7.1% of patients in the heparin-plus-Gp IIb/IIIa groups (odds ratio, 1.09; 95% confidence interval 0.90-1.32; P = .40). Prespecified statistical criteria for noninferiority to heparin plus Gp IIb/IIIa were satisfied for both end points. In-hospital major bleeding rates were significantly reduced by bivalirudin (2.4% vs 4.1%; P<.001).ConclusionsBivalirudin with provisional Gp IIb/IIIa blockade is statistically not inferior to heparin plus planned Gp IIb/IIIa blockade during contemporary PCI with regard to suppression of acute ischemic end points and is associated with less bleeding.

The clinical use of HMG CoA-reductase inhibitors and the associated depletion of coenzyme Q10. A review of animal and human publications.

Abstract: The depletion of the essential nutrient CoQ10 by the increasingly popular cholesterol lowering drugs, HMG CoA reductase inhibitors (statins), has grown from a level of concern to one of alarm. With ever higher statin potencies and dosages, and with a steadily shrinking target LDL cholesterol, the prevalence and severity of CoQ10 deficiency is increasing noticeably. An estimated 36 million Americans are now candidates for statin drug therapy. Statin-induced CoQ10 depletion is well documented in animal and human studies with detrimental cardiac consequences in both animal models and human trials. This drug-induced nutrient deficiency is dose related and more notable in settings of pre-existing CoQ10 deficiency such as in the elderly and in heart failure. Statin-induced CoQ10 deficiency is completely preventable with supplemental CoQ10 with no adverse impact on the cholesterol lowering or anti-inflammatory properties of the statin drugs. We are currently in the midst of a congestive heart failure epidemic in the United States, the cause or causes of which are unclear. As physicians, it is our duty to be absolutely certain that we are not inadvertently doing harm to our patients by creating a wide-spread deficiency of a nutrient critically important for normal heart function.

The resident experience on trauma: declining surgical opportunities and career incentives? Analysis of data from a large multi-institutional study.

Abstract: Purpose: The surgical resident experience with trauma has changed. Many residents are exposed to predominantly nonoperative patient care experiences while on trauma rotations. Data from a large multicenter study were analyzed to estimate surgical resident exposure to trauma laparotomy, diagnostic peritoneal lavage (DPL), and focused abdominal sonography for trauma (U/S). Methods: Centers completed a self-report questionnaire on their institutional demographics, admissions, and procedure for a 2-year period (1998-1999). Results: A total of 82 trauma centers that provide resident teaching were included. The included centers represent over 247,000 trauma admissions. The majority of trauma centers (65.9%) had > 80% blunt injury. Although all centers performed laparotomies, other results were more variable. For U/S, 24.2% performed none at all and 47.0% performed fewer than two U/S examinations per month. For DPLs, 3.8% performed none and 66.7% performed fewer than two per month. Assuming 1 night of 4 on call, the average surgical resident training at a trauma center performing > 80% blunt trauma has the potential to participate in only 15 trauma laparotomies, 6 diagnostic peritoneal lavages, and 45 ultrasound examinations per year. In addition, the resident will care for an average of 500 blunt trauma patients before performing a splenectomy or liver repair. Conclusion: Surgical resident experience on most trauma services is heavily weighted to nonoperative management, with a relatively low number of procedures, little experience with DPL, and highly variable experience with ultrasound. These data have serious implications for resident training and recruitment into the specialty.

Regulation of cell-cell interactions by phosphatidic acid phosphatase 2b/VCIP.

Abstract: We identified vascular endothelial growth factor and type I collagen inducible protein (VCIP), also known as phosphatidic acid phosphatase 2b (PAP2b), in a functional assay of angiogenesis. VCIP/PAP2b exhibits an Arg–Gly–Asp (RGD) cell adhesion sequence. Immunoprecipitation and fluorescence-activated cell sorting analyses demonstrated that VCIP-RGD is exposed to the outside of the cell surface. Retroviral transduction of VCIP induced cell aggregation/cell–cell interactions, modestly increased p120 catenin expression and promoted activation of the Fak, Akt and GSK3β protein kinases. Furthermore, expression of recombinant VCIP promoted adhesion, spreading and tyrosine phosphorylation of Fak, Shc, Cas and paxillin in endothelial cells. GST–VCIP-RGD, but not GST–VCIP-RGE, specifically interacted with a subset of integrins, and these interactions were effectively blocked by anti-αvβ3 and anti-α5β1 integrin antibodies, and by PAP2b/VCIP-derived peptides. Interestingly, PAP2b/VCIP is expressed in close proximity to vascular endothelial growth factor, von Willebrand factor and αvβ3 integrin in tumor vasculatures. These findings demonstrate an unexpected function of PAP2b/VCIP, and represent an important step towards understanding the molecular mechanisms by which PAP2b/VCIP-induced cell–cell interactions regulate specific intracellular signaling pathways.

Response of human mammary epithelial cells to DNA damage induced by BPDE: involvement of novel regulatory pathways.

Abstract: The responses of a line of normal human mammary epithelial cells, HME87, to treatment with the ultimate carcinogen benzo[a]pyrene diol epoxide (BPDE) were analyzed using a directed gene expression analysis technique, RAGE. Under conditions where cell number was decreased by 50% 24 or 48 h post-treatment, flow cytometry demonstrated no establishment of a G(1)/S arrest nor induction of apoptosis; cells continued to enter S phase from G(1) for at least 24 h but were blocked at G(2)/M. Using the RAGE technique, changes in gene expression were assayed for over 1000 genes, and multiple time-point data were collected for approximately 90 genes. In accord with the cell cycle studies, expression of the p21-WAF1 gene, the major mediator of p53-dependent G(1)/S arrest, did not increase until 24 h post-treatment. The expression of other target genes for transactivation by p53 was increased at early time points, including GADD45, an effector of the G(2)/M checkpoint, and WIP1. Analyses of proteins in treated cells indicated that p53 was phosphorylated at Ser15 but not at Ser20 within 30 min of treatment, and this correlated with an increase in the total amount of p53 protein. Significant expression changes were noted in a number of transcription factor genes, including ATF3 and E2A, genes that have not been previously connected to a response to DNA damage involving bulky chemical adducts. In addition, expression of the XPC gene was induced by BPDE treatment; the XPC product is thought to be involved in recognition of DNA damage by the nucleotide excision repair system.

GenePath: a system for automated construction of genetic networks from mutant data.

Abstract: Motivation: Genetic networks are often used in the analysis of biological phenomena. In classical genetics, they are constructed manually from experimental data on mutants. The field lacks formalism to guide such analysis, and accounting for all the data becomes complicated when large amounts of data are considered. Results: We have developed GenePath, an intelligent assistant that automates the analysis of genetic data. GenePath employs expert-defined patterns to uncover gene relations from the data, and uses these relations as constraints in the search for a plausible genetic network. GenePath formalizes genetic data analysis, facilitates the consideration of all the available data in a consistent manner, and the examination of the large number of possible consequences of planned experiments. It also provides an explanation mechanism that traces every finding to the pertinent data. Availability: GenePath can be accessed at http: //genepath.org. Contact: gadi@bcm.tmc.edu Supplementary information: Supplementary material is available at http://genepath.org/bi-supp.

PKC isozyme S -cysteinylation by cystine stimulates the pro-apoptotic isozyme PKCδ and inactivates the oncogenic isozyme PKCε

Abstract: Protein kinase C (PKC) is a family of ten isozymes that play distinct and in some cases opposing roles in cell growth and survival. We recently reported that diamide, a diazene carbonyl derivative which oxidizes thiols to disulfides through addition/displacement reactions at the diazene bond, induces potent GSH-dependent inactivation of several PKC isozymes, including the oncogenic isozyme PKCe, via S-glutathiolation. PKCδ, a pro-apoptotic isozyme, was distinguished by its resistance to inactivation. In this report, we show that PKC-regulatory S-thiolation modifications produced by physiological disulfides elicit opposing effects on PKCδ and PKCe activity. We report that PKCδ is stimulated 2.0–2.5 fold by GSSG, (Cys–Gly)2 and cystine, under conditions where PKCγ and PKCe are fully inactivated by cystine, and PKCα activity is affected marginally or not at all by the disulfides. Focusing on cystine, we show that DTT quenches cystine-induced PKCδ stimulation and PKCγ and PKCe inactivation, indicative of oxidative regulation. By analyzing DTT-reversible isozyme radiolabeling by [ 35 S]cystine, we demonstrate that PKCγ, PKCδ and PKCe are each [ 35 S] S-cysteinylated in association with the concentration-dependent regulation of isozyme activity by cystine. The restricted reactivity of cystine, together with the effects of DTT and thioredoxin on cystineinduced PKC isozyme regulation reported here, indicate that the cystine-induced PKC-regulatory effects entail isozyme S-cysteinylation. We recently hypothesized that antagonism of tumor promotion/progression by small cellular thiols may involve PKC regulation via oxidant-induced Sthiolation reactions with PKC isozymes. The findings of cystine-induced PKC isozyme regulation by S-cysteinylation reported here offer correlative support to the hypothetical model. Thus, PKCδ, a potent antagonist of DMBA– TPA-induced tumor promotion/progression in mouse skin, is stimulated by S-cysteinylation, PKCe, an important mediator of the tumor promotion/progression response, is inactivated by S-cysteinylation, and PKCα, which is not influential in DMBA–TPA-induced tumor promotion/progression, is not regulated by cystine. Furthermore, PKCγ has oncogenic activity, and S-cysteinylation inactivated PKCγ and PKCe similarly. These findings provide evidence that S-cysteinyl acceptor-sites in PKC isozymes may offer attractive targets for development of novel cancer preventive agents.

Susceptibility to vascular neoplasms but no increased susceptibility to renal carcinogenesis in Vhl knockout mice

Abstract: The von Hippel-Lindau (VHL) tumor suppressor gene plays a prominent role in the development of renal cell carcinoma (RCC) in humans. VHL functions as a ubiquitin E3 ligase, controlling the stability of hypoxia inducible factor (HIF) and tumor angiogenesis. Alterations in this tumor suppressor gene are rarely observed in spontaneous or chemically induced RCC that arise in conventional strains of rodents and Vhl knockout mice (Vhl +/- ) do not develop spontaneous RCC. We tested whether Vhl knockout mice exhibited increased susceptibility to renal carcinogenesis using the well-characterized renal carcinogen streptozotocin. No differences were observed between wild-type and Vhl +/- animals in the frequency or type of renal lesions induced by 50-200 mg/kg streptozotocin. Carcinogen-induced RCC that developed in Vhl heterozygotes and wild-type mice did not contain mutations in the wild-type Vhl, as determined by direct sequencing of the primary tumors. While Vhl +/- mice exhibited no increase in renal lesions in response to streptozotocin, heterozygous animals did develop vascular proliferative lesions of the liver, uterus, ovary, spleen and heart. These lesions, ranging from angiectasis to hemangiosarcoma, were most prominent in the livers of Vhl +/- mice, where they were found in high incidence and high multiplicity. Wild-type mice developed a low-frequency of liver angiectasis (7-15%) only at the highest doses of carcinogen used (150 and 200 mg/kg, respectively) while Vhl +/- mice exhibited angiectasis, hemangioma and hemangiosarcomas with a frequency ranging from 19 to 46% at 50-200 mg/kg streptozotocin. Untreated Vhl +/- mice had a spontaneous incidence of hepatic vascular lesions of 21%. Furthermore, vascular lesions of the uterus, ovary, spleen and heart were observed only in Vhl +/- mice, with an incidence of (5-28%). Taken together, the data indicate that heterozygosity at the Vhl locus predisposes mice to a vascular phenotype ranging from angiectasis to hemangiosarcoma, consistent with the ability of this tumor suppressor gene to control the stability of HIF and regulate key proteins that participate in angiogenesis.

Metachromatic leukodystrophy: a model for the study of psychosis.

Abstract: Figure 1. Serial CT in a young adult female patient with adult-onset metachromatic leukodystrophy (MLD). Axial CT images (left) of a female with auditory hallucinations, agitation, grandiose and paranoid delusions. Cognitive testing showed IQ 78, attentional errors, psychomotor slowing, impaired verbal and nonverbal memory, and concreteness. Behavioral changes began at age 17 with deterioration of school performance, promiscuity, and polysubstance abuse. Note the enlarged ventricles andwhite matter attenuation. Follow-up CT (right) 9 years later showed progression of white matter attenuation and increased ventricular size, consistent with cerebral atrophy. Concurrently she exhibited urinary and fecal incontinence, global deficiencies in self-care, marked apathy, and was unable to name the month or recite the alphabet. Pseudobulbar affect, imitation behavior, primitive and brisk tendon reflexes without other neurological abnormalities were present. Arylsulfatase A was absent in leukocytes. An older brother was similarly but more severely affected.

Sirolimus: a current perspective.

Abstract: Sirolimus, a macrocyclic lactone that displays a novel mechanism of immunosuppressive action, is a critical-dose drug requiring therapeutic drug monitoring for optimal outcomes. The compound was documented in two multicenter, blinded clinical trials to reduce the incidence of acute rejection episodes when used in combination with cyclosporine and steroids vs. azathioprine or placebo comparators. Furthermore, studies utilizing cyclosporine withdrawal documented a long-term benefit on renal function of chronic sirolimus therapy, albeit with a modestly enhanced incidence of acute rejection episodes. Although this application may be useful in selected cases, we believe that minimal initial cyclosporine exposures de novo mitigate the need for eventual withdrawal for chronic nephropathy, while preserving the immunosuppressive synergy during the maintenance phase. Recipients treated de novo with a sirolimus-cyclosporine combination tolerate steroid withdrawal at 1 month after living-donor or at 3 to 6 months after cadaveric kidney transplantation with only a 5% risk of acute rejection episodes and 6% incidence of chronic reactions within 3 years. However, sirolimus exacerbates the hypertriglyceridemic and hypercholesterolemic proclivities of transplant recipients, as well as exerts myelosuppressive effects, which are augmented by concomitant therapy with azathioprine or, particularly, with mycophenolate mofetil. Due to its apparent lack of nephrotoxicity, sirolimus has been employed for induction therapy in a calcineurin antagonist-free regimen in combination with either basiliximab or rabbit antilymphocyte sera for weak or strong immune responders, respectively, followed by introduction of a calcineurin antagonist upon resolution of the ischemia-reperfusion injury. Therefore, sirolimus proffers a potent and unique platform for new immunosuppressive strategies in organ transplantation.

Localization of a novel autosomal recessive non-syndromic hearing impairment locus (DFNB38) to 6q26-q27 in a consanguineous kindred from Pakistan.

Abstract: For autosomal recessive nonsyndromic hearing impairment over 30 loci have been mapped and 19 genes have been identified. DFNB38, a novel locus for autosomal recessive nonsyndromic hearing impairment, was localized in a consanguineous Pakistani kindred to 6q26-q27. The affected family members present with profound prelingual sensorineural hearing impairment and use sign language for communications. Linkage was established to microsatellite markers located on chromosome 6q26-q27 (Multipoint lod score 3.6). The genetic region for DFNB38 spans 10.1 cM according to the Marshfield genetic map and is bounded by markers D6S980 and D6S1719. This genetic region corresponds to 3.4 MB on the sequence-based physical map.

Systematic review: health-related quality of life in functional dyspepsia

Abstract: Background: We performed a systematic review of the literature to compare the health-related quality of life (HRQOL) of patients with functional dyspepsia with either healthy controls or those with other diseases. Methods: Full-length published manuscripts during 1980–2002 were included if (a) patients had functional dyspepsia, but not uninvestigated dyspepsia; and (b) HRQOL was measured using a validated generic or dyspepsia-specific instruments, but not global assessment alone. Results: Twelve studies were reviewed; six fulfilled the selection criteria. None examined HRQOL among samples of the general population. None used dyspepsiaspecific HRQOL instruments. Three studies contained four comparisons of HRQOL between functional dyspepsia patients and controls; two studies examined HRQOL changes in response to therapy. Two studies demonstrated a significant reduction at least in some domains of HRQOL among patients with functional dyspepsia compared to controls, while one study was negative. In general, studies that reported a decline in HRQOL Short Form-36 (SF-36) showed that changes in the physical domain were similar to those on mental domain of the SF-36. Conclusions: There is some evidence for a decrease in HRQOL in patients with moderate to severe functional dyspepsia who seek care for their symptoms; however, more studies are needed. A therapeutic response in functional dyspepsia-related pain or discomfort might result in a corresponding improvement in HRQOL.

Ubiquitin-dependent and -independent proteasomal degradation of apoB associated with endoplasmic reticulum and Golgi apparatus, respectively, in HepG2 cells.

Abstract: Studies in hepatocyte cultures indicate that apolipoprotein (apo) B-100 production is regulated largely by intracellular degradation and the proteasome pathway is a major mechanism for the degradation. In the present study, we have examined the detailed itinerary of apoB degradation through its secretory pathway in HepG2 cells. We found that ubiquitin-dependent proteasomal degradation of apoB largely occurred on the cytosolic surface of rough and smooth endoplasmic reticulum (ER) and that a small proportion of apoB was dislodged from the secretory organelles into the cytosolic compartment where it underwent ubiquitination for proteasomal degradation. The transmembrane conformation of apoB persisted as the protein was transported through the Golgi apparatus. We further demonstrated that proteasomal degradation of apoB was associated the Golgi apparatus but Golgi-associated apoB was not ubiquitinated, indicating an ubiquitin-independent proteasomal degradation of apoB is associated with this organelle. We conclude that apoB undergoes proteasomal degradation while going through different compartments of the secretory pathway; further, ER-associated proteasomal degradation of apoB in the ER is ubiquitin-dependent whereas that occurring in the Golgi is ubiquitin-independent.

Enhanced gene expression system

Abstract: The present disclosure provides an enhanced gene transcription system including a systematic method of selecting efficient promoter-enhancers, of optimizing plasmid design and increasing transcription of a cDNA of interest in transfected target cells. The present invention identifies abundantly, selectively expressed genes and creates plasmids comprising the promoters-enhancers of those genes.

An adjustable-threshold algorithm for the identification of objects in three-dimensional images.

Abstract: Motivation: To develop a highly accurate, practical and fast automated segmentation algorithm for threedimensional images containing biological objects. To test the algorithm on images of the Drosophila brain, and identify, count and determine the locations of neurons in the images. Results: An ew adjustable-threshold algorithm was developed to efficiently segment fluorescently labeled objects contained within three-dimensional images obtained from laser scanning confocal microscopy, or two-photon microscopy. The result of the test segmentation with Drosophila brain images showed that the algorithm is extremely accurate and provided detailed information about the locations of neurons in the Drosophila brain. Centroids of each object (nucleus of each neuron) were also recorded into an algebraic matrix that describes the locations of the neurons. Availability: Interested parties should send their request for the NeuronMapper TM program with the segmentation

Functional Magnetic Resonance Imaging: Application to Posttraumatic Stress Disorder

Abstract: Cover and Figure 1. Several areas believed to be important in posttraumatic stress disorder (PTSD) are indicated in color on sagittal and axial T1-weighted magnetic resonance (MR) images from a normal individual: rostral anterior cingulate cortex (blue), amygdala (pink), hippocampus (yellow). The approximate location of the axial section is indicated on the midline sagittal MR image. Broca’s area has also been implicated (not illustrated).

Interaction of amino acids and insulin in the regulation of protein metabolism in growing animals

Abstract: Young animals utilize their dietary amino acids more efficiently for growth because they are capable of a greater increase in tissue protein synthesis in response to feeding than older animals. This response to feeding is particularly profound in skeletal muscle. The feeding-induced stimulation of protein synthesis in skeletal muscle is uniquely and independently regulated by both insulin and amino acids. In most visceral tissues, the stimulation of protein synthesis by feeding is mediated by amino acids alone and not by insulin. The stimulation of protein synthesis by nutrition and hormones is regulated by alterations in the expression and activity of components of the intracellular signaling pathways that control the initiation of translation. Key words: Muscle, pigs, neonate, protein synthesis, insulin, amino acids

Resuscitating hypothermic dogs after 2 hours of circulatory arrest below 6 degrees C.

Abstract: Background: Ultraprofound hypothermia may have a place in trauma rescue and resuscitation. We describe resuscitation of dogs after asanguhteous perfusion and circulatory arrest of 2 hours at 2° to 4°C. Methods: Nine dogs were cooled using a bypass apparatus and their circulating blood replaced with bicarbonated Hextend (Abbott, North Chicago, IL). Perfusion was continued to 2° to 4°C, and 60 mL of 2 mol/L KCl and 20 mL of 50% MgSO 4 .7H 2 O were infused intra-arterially, and circulation was arrested for 2 hours. The dogs were then rewarmed, transfused, defibrillated, weaned from bypass, and allowed to awaken. Preoperative and postoperative biochemistry and hematology were compared. Results: Six dogs recovered fully. One of these dogs died of an infection 2 weeks later. Three other dogs never recovered because of technical or procedural difficulties. Biochemical and hematologic parameters were normal by 3 weeks. Conclusion: Hypothermic blood substitution with Hextend allows resuscitation after 2 hours of ice-cold circulatory arrest in dogs.