Biomedical subjects
Publications and source records attributed to David A Clark.
A series of azole-fused salicylamides were prepared as analogues of antimycin and assayed for activity at complex III of the mitochondrial respiratory chain. The activity of these compounds approached that of antimycin in inhibitory potency and some showed growth reduction of Septoria nodorum in vitro. Compound 8a was shown to bind at the Qi site of complex III by red-shift titration of the bc1 complex.
Previous studies from our laboratory have shown that fulminant hepatitis caused by the mouse hepatitis virus, MHV-3, is dependent on production of the novel immune coagulant fgl2/fibroleukin. In this study, we investigate the role of IFN-gamma and TNF-alpha in the induction of fgl2 expression and fgl2-dependent hepatic apoptosis. Infusion of IFN-gamma in combination with TNF-alpha through the portal vein of fgl2+/+ mice led to widespread hepatic apoptosis and fibrin deposition. Livers from fgl2-/- mice were normal, although strong expression of the fgl2 knockout reporter gene Lac Z was seen in both resident hepatic macrophages and endothelial cells. In vitro, IFN-gamma and TNF-alpha induced fgl2 expression in a macrophage and endothelial cell-specific manner. In macrophages (peritoneal and RAW 264.7 cells), IFN-gamma, but not IFN-alpha, LPS, TNF-alpha, or IL-1 induced fgl2 mRNA transcription and protein expression, while in endothelial cells TNF-alpha, but not IFN-gamma, induced fgl2 transcription. In addition, while TNF-alpha enhanced IFN-gamma-induced macrophage fgl2 transcription, IFN-gamma also enhanced TNF-alpha-induced endothelial cell fgl2 transcription. The induction of fgl2 by IFN-gamma in macrophages involved a STAT1-dependent pathway, involving the composite cis elements Sp1/Sp3 and GAS/PU.1. The latter interacted with IFN-gamma-dependent Sp1/Sp3, STAT1, and the ETS family of transcription factors member PU.1. The interaction of PU.1 with the IFN-gamma-activated sequence/ETS family of transcription factors site determined the macrophage-specific induction of fgl2 by IFN-gamma. Overall, this study demonstrates that IFN-gamma and TNF-alpha induce hepatocyte apoptosis in vivo, which is dependent on induction of fgl2, and defines the molecular basis of transcription of fgl2 in vitro.
PROBLEM: Intravenous Immunoglobulins (IVIG) are widely used off label in the treatment of early reproductive failure. As IVIG is expensive, and may have side-effects, evidence of efficacy is needed. Previous results have suggested that the pre-conception treatment of primary recurrent abortion patients might be effective, but the data set has been too small for adequate statistical power. More recently it has been suggested that IVIG may improve the success rate of in vitro fertilization and embryo transfer (IVF) in patients with prior IVF failures, but clinical trials have given conflicting results that need explanation. Systematic reviews generating inconclusive results have focused on methodological rigor to the exclusion of biological plausibility. METHODS: Review of current basic science of design, measurement, and evaluation of clinical trials and basic science mechanisms providing a rationale for treatment. Meta-analysis of published randomized controlled and cohort-controlled trials (updated with two unpublished data sets) evaluating IVIG treatment in IVF failure patients. Live birth rate was used as the most relevant endpoint. The ability of different sources of IVIG to suppress natural killer (NK) cell activity was determined using a standard (51)Cr-release assay in vitro. RESULTS AND CONCLUSIONS: Meta-analysis of three published randomized controlled trials (RCTs) of IVIG in IVF failure patients shows a significant increase in the live birth rate per woman (p = 0.012; Number Needed to Treat for 1 additional live birth, NNT = 6.0 women). Using live birth rate per embryo transferred, and adding data from two cohort-controlled trials to the meta-analysis further supports this conclusion (overall p = 0.000015, NNT = 3.7 women). Relevant variables appear to include properties and scheduling of the IVIG, and selection of patients with abnormal immune test results. Different IVIG preparations vary significantly in their ability to suppress NK activity in vitro. A rationale for use of IVIG is provided by a review of mechanisms of IVIG action and mechanisms underlying failure of chromosomally normal embryos.
Secondary prevention of plaque rupture following percutaneous coronary intervention in patients with acute coronary syndrome is not well studied. This case report describes a 53-year-old man who experienced plaque rupture between two previously successfully implanted stents in the right coronary artery, as documented during the 3rd intervention using intravascular ultrasound.
Advanced proteomic research efforts involving areas such as systems biology or biomarker discovery are enabled by the use of high level informatics tools that allow the effective analysis of large quantities of differing types of data originating from various studies. Performing such analyses on a large scale is not feasible without a computational platform that performs data processing and management tasks. Such a platform must be able to provide high-throughput operation while having sufficient flexibility to accommodate evolving data analysis tools and methodologies. The Proteomics Research Information Storage and Management system (PRISM) provides a platform that serves the needs of the accurate mass and time tag approach developed at Pacific Northwest National Laboratory. PRISM incorporates a diverse set of analysis tools and allows a wide range of operations to be incorporated by using a state machine that is accessible to independent, distributed computational nodes. The system has scaled well as data volume has increased over several years, while allowing adaptability for incorporating new and improved data analysis tools for more effective proteomics research.
Umbilical arterial catheters (UAC) are routinely used in the care of critically ill newborns. Complications related to UACs include vascular compromise, hemorrhage, complications related to malposition, severance of the catheter itself, and infection. This article is Part II in a series dedicated to assessing infants with an umbilical catheter. Part I focused on infants with umbilical venous catheters; this article will focus on the physical assessment relevant to infants with an UAC. Complications related to UACs can occur during any phase of treatment: insertion, while indwelling, or after discontinuing the catheter. Review of clinical signs of complications along with clinical photographs, will assist caregivers in promptly recognizing UAC-related complications.
The 25-item Clark-Beck Obsessive-Compulsive Inventory (CBOCI) was developed to assess the frequency and severity of obsessive and compulsive symptoms. The measure uses a graded-response format to assess core symptom features of obsessive-compulsive disorder (OCD) based on Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) criteria and current cognitive-behavioral formulations. Revisions were made to the CBOCI on the basis of psychometric and item analyses of an initial pilot study of clinical and nonclinical participants. The construct validity of the revised CBOCI was supported in a subsequent validation study involving OCD, nonobsessional clinical, and nonclinical samples. A principal-factor analysis of the 25 items found 2 highly correlated factors of Obsessions and Compulsions. OCD patients scored significantly higher on the measure than nonobsessional anxious, depressed, and nonclinical samples. The questionnaire had strong convergent validity with other OCD symptom measures but more modest discriminant validity.
The past decade has witnessed a significant shift toward a more cognitive emphasis in our understanding and treatment of obsessive-compulsive disorders (OCD). This article discusses the shortcomings in more standard behavioral treatment of OCD, which despite its demonstrated efficacy, led to the recent cognitive-behavioral approaches to the disorder. Current cognitive behavior therapy for OCD is described and a short critical review of the comparative treatment outcome literature on cognitive behavior therapy vs exposure and response prevention is provided. The article concludes that although the clinical utility of a more cognitive approach to OCD has not been consistently demonstrated, it would be premature to abandon cognitive formulations until some key research questions have been addressed.
BACKGROUND: Preoperative hookwire localizations have been used for some years to guide excision of subclinical breast lesions. With the availability of ultrasonography in the operating theatre, these localizations can be done intraoperatively. METHODS: One hundred and thirty lesions in 112 consecutive patients with impalpable breast lesions were intraoperatively localized and excised, obviating the need for preoperative localizations. RESULTS: All 130 lesions were detected intraoperatively and excised. Forty-four patients elected to have their benign lesions excised and there were 32 cancers removed. Ultrasonography was used to ensure complete local excisions in the majority of the cancers. CONCLUSION: Intraoperative breast ultrasound is a reliable, rapid and cost-effective adjunct in the management of both benign and malignant breast lesions.
PROBLEM: Prevention of spontaneous abortion by allogeneic mononuclear leukocyte immunotherapy has proven ineffective in the CBA x DBA/2 murine abortion model if the leukocytes are stored overnight before inoculation. The mechanism and generality of the phenomenon has not been elucidated. METHODS: As prevention of recurrent abortion in the CBA x DBA/2 model requires allogeneic BALB/c lymphoid cells bearing paternal antigens and the tolerance-signaling molecule CD200 (OX-2), we evaluated effects of cell storage on cell surface CD200 expression using flow cytometry of fresh or stored cells stained with monoclonal anti-CD200 antibody. Release of putative CD200 molecules into culture supernatant during storage was tested by the ability of supernatants to block binding of anti-CD200 to freshly isolated cells. Similar studies were done using human peripheral blood mononuclear leukocytes. Possible binding of soluble CD200 to immunoglobulin G (IgG) molecules in plasma as a basis for the anti-abortive effect of intravenous immunoglobulin G (IVIG) was tested using the standard peripheral blood lymphocyte (PBL) natural killer (NK) cell lysis of (51)Cr-labeled K562 cells and monoclonal anti-human CD200 antibodies. RESULTS: Loss of anti-abortive effect of BALB/c cells with overnight storage at 4 degrees C and blocking of protective effect of freshly isolated cells with anti-CD200 antibody was confirmed. Supernatants of stored cells acquired a low level of protective activity against abortion in the CBA x DBA/2 model. Cell surface CD200 was lost with overnight storage at 4 or 22 degrees C, and supernatants acquired the ability to block binding of anti-CD200 antibody to fresh cells. Similar results were obtained using human PBL. However, if cells were stored overnight in IgG containing plasma, binding was not blocked. Suppression of NK cell lysis by PBL was abrogated if anti-CD200 antibody was added to the assay. CONCLUSIONS: Loss of the tolerance signal CD200 from allogeneic cells occurs with storage overnight, and their ability to protect against abortion is lost. CD200 appears to be shed into the supernatant, and may associate with IgG molecules rendering IVIG suppressive.
PROBLEM: Indoleamine 2,3-dioxygenase (IDO) expression in fetal trophoblast and decidual antigen-presenting cells has been proposed to inactivate maternal T cells and thereby prevent rejection of the "fetal allograft" in early pregnancy. Psychic stress has been proposed to cause miscarriages as well as infertility, at the same time in pregnancy when blockade of IDO causes loss, but the suggested mechanism of stress-triggered loss has been an increased ratio of pro-rejection Th1-type cytokines to anti-rejection Th2/3 cytokines. Could stress act by reducing IDO expression? METHODS: Using DBA/2-mated A/J mice where stress causes early pregnancy failure, we examined the role of stress in reducing IDO versus increasing Th1/Th2 ratio in deciduas. IDO loss was also examined in human decidua associated with pregnancy failure. RESULTS: A post-implantation sonic stress increased the pregnancy failure rate, increased the Th1/Th2 ratio, but did not reduce IDO. IDO was reduced, and Th1/Th2 ratios increased in A/J mice pre-immunized against paternal DBA/2 antigens, and concomitant stress increased these effects. The rate of pregnancy failure was not further increased consistent with recent discoveries of factors that limit the impact of Th1 cytokines at the feto-maternal interface. In deciduas from spontaneous miscarriage patients, IDO(+) cell frequencies were low in only 30% of patients. CD3(+) T-cell numbers and percentage terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end-labelling (TUNEL)(+) apoptotic T cells were increased, but the level of IDO did not correlate with likelihood of apoptosis. CONCLUSIONS: Loss of an allogeneic embryo in early pregnancy is more likely to be due to a high Th1/Th2 ratio than loss of putative protection by IDO.
Mechanisms explaining maternal tolerance of her semiallogeneic histoincompatible fetus have been proposed to include a number of unique signaling molecules including CD200, novel MHC class I-b molecules such as HLA-G and HLA-E, Th2,3 cytokines, apoptosis-inducing molecules such as FASL, and indoleamine 2,3-dioxygenase. Novel CD4+ CD25+ Treg cells and gammadelta T cell receptor-positive regulatory cells appear to play key roles in responding to and in generating signals. This chapter will critically review current data concerning the mechanisms and relevance of the various proposed mechanisms.
Recognition of the clinical features of Trisomy 13 syndrome, a common autosomal trisomy, provides the basis for diagnostic testing and counseling of families. This article provides a systematic guide to physical assessment and photographs to enhance recognition of this genetic disorder. The principles of numerical chromosomal abnormalities as related to trisomies are reviewed. An abnormal development of the forebrain, holoprosencephaly, is the most common cranial abnormality in infants with Trisomy 13. The embryology and implications of holoprosencephaly are described. A discussion of antenatal diagnosis of Trisomy 13 and delivery room management is also provided. The diagnosis of Trisomy 13 is confirmed antenatally or after delivery with genetic testing. Prognosis of infants with Trisomy 13 and implications for the infants development are described.
BACKGROUND: Donor leucocytes (DL) play an important role in rat liver transplant tolerance and their postoperative administration can convert rejection to tolerance. They appear to induce early activation, altered patterns of infiltration and death of recipient alloreactive T cells. The ability of immunosuppressive drugs to combine with DL administration was examined in a rat heart transplant model. METHODS: Immediately after PVG to DA heterotopic heart transplantation, 6 x 10(7) spleen DL were injected. Cyclosporine A (CsA), 1.5 mg/kg/day, or methotrexate (MTX), 0.1 or 0.2 mg/kg/day, were given from day (d) 0 to d4 (early) or from d3 to d7 (delayed). Castanospermine (CAST) was administered from d0 to d7 at 100 or 300 mg/kg/day. In a separate experiment, transplanted hearts and recipient spleens were collected from treatment groups for analysis of infiltrate and cytokine mRNA expression. RESULTS: Delayed treatment with CsA or early treatment with MTX but not CAST combined with DL to result in prolonged graft survival. Recipients treated with DL and delayed CsA had a reduced level of intra-graft interleukin (IL)-2, interferon (IFN)-gamma, IL-4, and IL-4R mRNA expression and reduced infiltrate compared to DL alone. Early MTX plus DL led to almost complete inhibition of all markers of inflammation during treatment followed by a rapid increase after cessation. In combination with DL, CsA was more effective than MTX for induction of donor-specific tolerance at the dose and administration regimens tested. CONCLUSIONS: Delayed CsA or early MTX combine with DL to prolong heart allograft survival. Early and extensive inhibition of rejection by MTX was less effective than delayed and partial inhibition of the response by CsA for induction of transplant tolerance.
OBJECTIVE: We sought to evaluate the use of the Ronald McDonald House (RMH) for selected high-risk pregnant women. METHODS: Beginning in November of 1999, women on the Maternal Fetal Medicine service at Albany Medical Center Hospital (AMCH) were candidates for antepartum lodging at the Ronald McDonald House (RMH). Women whose only indication for antepartum hospitalization was to maintain proximity to a tertiary care center were offered stays at the RMH. Antenatal and neonatal outcomes were reviewed. RESULTS: A total of 41 antepartum subjects stayed at the RMH during the study period. No adverse perinatal outcomes were identified due to utilization of the RMH. Patients stayed at the RMH instead of staying at AMCH as inpatients for a total of 586 days during the study period. CONCLUSIONS: Outpatient management at the RMH is a cost-effective alternative for selected high-risk pregnancies. No adverse outcomes in the study population were attributable to the utilization of the RMH.
PROBLEM: How to evaluate immunological therapy advocated for recurrent spontaneous abortion and implantation failure. I was invited to comment on the opinion article of Chaouat (AJRI December 2003). METHODS: A critical examination of key beliefs and application of the principles of evidence and logic utilizing current data. RESULTS AND CONCLUSIONS: Although rationale has no bearing on efficacy of proposed treatments and is not sufficient justification for routine practice, insufficient attention to data concerning patient selection, insufficient attention to treatment methodology, and lack of full disclosure in some clinical trials needs to be corrected. A more systematic collection of follow-up data is needed.
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