Solution structure of the dimeric cytoplasmic domain of syndecan-4

The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

Multiple ligand interaction of alpha-synuclein produced various forms of protein aggregates in the presence of Abeta25-35, copper, and eosin

Various protein aggregates of alpha-synuclein developed by way of the common protein self-oligomerization in the presence of Abeta25-35, copper, and eosin were examined. All the aggregates exhibited congo red birefringence although the actual amounts of the aggregates were varied as determined by thioflavin T binding fluorescence. When their morphologies were analyzed in relation to in vitro cytotoxicity, the smallest granular aggregates obtained with copper exhibited the highest cytotoxicity, while the fibrous structures by eosin did not affect the cell.

4-Hydroxytamoxifen binds to and deactivates the estrogen-related receptor gamma

The estrogen-related receptors (ERR alpha, ERR beta, and ERR gamma) form a family of orphan nuclear receptors that share significant amino acid identity with the estrogen receptors, but for which physiologic roles remain largely unknown. By using a peptide sensor assay, we have identified the stilbenes diethylstilbestrol (DES), tamoxifen (TAM), and 4-hydroxytamoxifen (4-OHT) as high-affinity ligands for ERR gamma. In direct binding assays, 4-OHT had a K(d) value of 35 nM, and both DES and TAM displaced radiolabeled 4-OHT with K(i) values of 870 nM. In cell-based assays, 4-OHT binding caused a dissociation of the complex between ERR gamma and the steroid receptor coactivator-1, and led to an inhibition of the constitutive transcriptional activity of ERR gamma. ERR alpha did not bind 4-OHT, but replacing a single amino acid predicted to be in the ERR alpha ligand-binding pocket with the corresponding ERR gamma residue allowed high-affinity 4-OHT binding. These results demonstrate the existence of high-affinity ligands for the ERR family of orphan receptors, and identify 4-OHT as a molecule that can regulate the transcriptional activity of ERR gamma.

A novel cyclooxygenase-inhibitory stilbenolignan from the seeds of Aiphanes aculeata

[structure: see text] Aiphanol (1), a novel stilbenolignan, along with isorhapontigenin (2), piceatannol (3), and luteolin, were isolated by bioassay-guided fractionation from the seeds of Aiphanes aculeata Willd. (Arecaceae). The structure of compound 1 was elucidated by spectroscopic methods. Compound 1 is based on an unprecedented stilbenolignan skeleton in which a stilbene moiety is linked with a phenylpropane unit through a dioxane bridge. Compounds 1 and 2 exhibited significant inhibitory activities against cyclooxygenases-1 and -2.

Viral interferon regulatory factor 1 of Kaposi's sarcoma-associated herpesvirus binds to p53 and represses p53-dependent transcription and apoptosis

Kaposi's sarcoma-associated herpesvirus (KSHV) is related to the development of Kaposi's sarcoma. Open reading frame K9 of KSHV encodes viral interferon regulatory factor 1 (vIRF1), which functions as a repressor of interferon- and IRF1-mediated signal transduction. In addition, vIRF1 acts as an oncogene to induce cellular transformation. Here we show that vIRF1 directly associates with the tumor suppressor p53 and represses its functions. The vIRF1 interaction domains of p53 are the DNA binding domain (amino acids [aa] 100 to 300) and the tetramerization domain (aa 300 to 393). p53 interacts with the central region (aa 152 to 360) of vIRF1. vIRF1 suppresses p53-dependent transcription and deregulates its apoptotic activity. These results suggest that vIRF1 may regulate cellular function by inhibiting p53.

Is prosthetic renal artery reconstruction a durable procedure? An analysis of 489 bypass grafts

OBJECTIVE

Renal artery stenosis has been classically addressed with saphenous vein bypass graft or transaortic endarterectomy performed either primarily or in combination with an aortic procedure. In this series, we report the outcome of our 12-year experience with renal artery reconstruction using prosthetic conduit.

METHODS

Patients undergoing renal artery bypass grafting from 1987 to 1999 were identified. Demographics, indications, concurrent operations, complications, and patency were analyzed. Patients underwent postoperative duplex scan with subsequent ultrasound scans at 6-month intervals.

RESULTS

There were 489 procedures performed in 414 patients with indications: high-grade renal artery stenosis in combination with abdominal aortic aneurysm repair or symptomatic aortoiliac occlusive disease (309 [63%]), renovascular hypertension (118 [24%]), and renal salvage (20 [4%]). Indications for the remainder included trauma, renal artery aneurysm, or an infected aortic graft. Inflow was aorta or aortic graft in 95% of patients with the remainder taken from the iliac or visceral vessels. The retroperitoneal approach was used in 97.8%. Nonfatal complications occurred in 11.4% with a 1.4% early and 4.8% late occlusion rate. Renal function worsened in 3.1% of all patients. Secondary patency at 1 and 5 years was 98% and 96%, respectively.

CONCLUSION

Renal artery reconstruction with prosthetic conduit has an acceptable and durable result whether used for primary renal artery reconstruction or concomitant reconstruction with aortic procedures.

A brief report on the Penn Inventory for posttraumatic stress disorder

In this report we provide normative data for the Penn Inventory for posttraumatic stress disorder for men and women who were referred to a specialist outpatient clinic following a range of traumatic events. Data are provided from clinical assessment of 80 people. There was no significant difference between male and female scores. Using the Clinician Administered PTSD Scale to ascertain diagnostic status and Hammarberg's cut-off criterion of 35, the Penn Inventory showed a sensitivity of .90 for male participants and .89 for female participants and a specificity of .55 for male participants and .67 for female participants. The Penn Inventory correlated highly with other measures of psychological distress. We discuss that the Penn Inventory may be best used as a screening instrument or measure of change of general mental well-being after trauma, rather than a diagnostic tool for specific traumatic stress symptoms.

Automatic skeleton generation for visualizing 3D, time-dependent fluid flows: application to the virtual aneurysm

Intracranial aneurysms are the primary cause of non-traumatic subarachnoid hemorrhage. Difficulties in identifying which aneurysms will grow and rupture arise because the physicians lack important anatomic and hemodynamic information. Through simulation, this data can be captured, but visualization of large simulated data sets becomes cumbersome, often resulting in visual clutter and ambiguity. To address these visualization issues, we developed an algorithm that extracts a skeleton of the patterns in 3D, time-dependent blood flow. The algorithm decomposes the blood flow into "bare-bones" components that can be visualized individually or superimposed together to formulate an understanding of the flow patterns in the aneurysm.

Cyclooxygenase-inhibitory and antioxidant constituents of the aerial parts of Antirhea acutata

Two new compounds, (6S)-hydroxy-29-nor-3,4-seco-cycloart-4(30),24-dien-3-oic acid (1) and 8-[1-(3,4-dihydroxyphenyl)-3-methoxy-3-oxopropyl]epicatechin (3), were isolated by bioassay-guided fractionation from the aerial parts of Antirhea acutata (DC.) Urb. (Rubiaceae). Compound 1 showed moderate inhibitory activities in cyclooxygenase-1 and -2 assays (IC(50) 43.7 and 4.7 microM, respectively), while compound 3 was active in 1,1-diphenyl-2-picrylhydrazyl free-radical and cytochrome c reduction antioxidant assays (IC(50) 29.1 and 16.3 microM, respectively). Additionally, one further new compound was isolated, (3S,24S)-25-trihydroxy-9,19-cycloartane-29-oic acid (2), but this was inactive in the bioassay systems used. Compound 1 is based on the unprecedented 29-nor-3,4-seco-cycloartane skeleton.

Mediastinitis associated with foreign body erosion of the esophagus in children

OBJECTIVE

Timely and experienced intervention for esophageal foreign bodies generally allows for removal with minimal morbidity. However, esophageal foreign bodies present a risk for esophageal perforation and subsequent mediastinitis, especially if the diagnosis of the foreign body is delayed. Although much has been written about the management of esophageal foreign bodies and their complications, little has been mentioned in recent literature about the specific complication of mediastinitis. This review was performed to examine our experience with this uncommon complication of esophageal foreign bodies.

METHODS

A retrospective review of the esophageal foreign body database at Children's Hospital of Wisconsin from 1987 to 1997 was performed to identify patients with esophageal foreign bodies and subsequent mediastinitis.

RESULTS

Four patients with esophageal perforation with associated mediastinitis secondary to retained esophageal foreign bodies were identified. Three of the four patients were treated with conservative measures consisting of foreign body removal, intravenous antibiotics and discontinuing of oral nutrition. These patients all achieved resolution of their mediastinitis and esophageal perforation with subsequent return to normal diets and no significant morbidity. One patient, with vascular erosion, required aggressive, invasive therapy.

CONCLUSION

From review of this limited number of patients, in the absence of major vascular erosion, conservative methods of treating children with foreign body esophageal perforation and subsequent mediastinitis appears to be effective.

Signaling pathways activated by alpha1-adrenergic receptor subtypes in PC12 cells

PC12 cells were used to compare signaling pathways activated by alpha1-adrenergic receptor (AR) subtypes. PC12 cells were transfected with human alpha1A, alpha1B, or alpha1D-ARs, and subclones stably expressing receptor densities in physiological ranges isolated and characterized. Norepinephrine (NE) activated a large number of signaling pathways in transfected cells, including inositol phosphate formation, intracellular calcium, all three arms of the mitogen activated protein kinase pathways, and a number of tyrosine kinases. Activation of mitogen activated protein kinase pathways and tyrosine kinases was not blocked by chelation of intracellular calcium with BAPTA or inhibition of protein kinase C. NE also activated luciferase reporter constructs for seven different transcription factors (AP1, SRE, CRE, NFkappaB, NFAT, Stat, GAS) following transfection into alpha1A-AR expressing PC12 cells. However, similar increases in inositol phosphate formation and intracellular Ca2+ caused by purinergic P2Y2 receptor activation did not activate any of these reporters. Comparison of alpha1-AR subtypes showed that the alpha1A activated all seven reporters, the alpha1B showed smaller effects, while the alpha1D was ineffective. NE caused differentiation of alpha1A, but not alpha1B or alpha1D, -AR expressing PC12 cells similar to that caused by NGF. This NE-induced differentiation was reduced or blocked by all inhibitors tested. We conclude that alpha1-ARs activate many signaling pathways and transcriptional responses in PC12 cells, which are not linearly related to second messenger production, and which may differ for different alpha1-AR subtypes.

Potent and selective nonpeptide inhibitors of caspases 3 and 7

5-Dialkylaminosulfonylisatins have been identified as potent, nonpeptide inhibitors of caspases 3 and 7. The most active compound within this series (34) inhibited caspases 3 and 7 in the 2-6 nM range and exhibited approximately 1000-fold selectivity for caspases 3 and 7 versus a panel of five other caspases (1, 2, 4, 6, and 8) and was at least 20-fold more selective versus caspase 9. Sequence alignments of the active site residues of the caspases strongly suggest that the basis of this selectivity is due to binding in the S2 subsite comprised of residues Tyr204, Trp206, and Phe256 which are unique to caspases 3 and 7. These compounds inhibit apoptosis in three cell-based models: human Jurkat T cells, human chondrocytes, and mouse bone marrow neutrophils.

Novel mimics of sialyl Lewis X: design, synthesis and biological activity of a series of 2- and 3-malonate substituted galactoconjugates

A series of potent inhibitors of P-selectin as potential anti-inflammatory agents is reported. These compounds are derivatives of galactocerebrosides bearing a malonate side chain in positions 2 and 3 of the galactose moiety. Based on the binding mode of sialyl Lewis X, the two acidic groups of the malonate are designed to form ionic interactions with two important lysines in the active site of P-selectin, Lys113 and Lys111. On the other hand, the 4- and 6-hydroxy groups on the galactose ring are arranged to chelate the calcium ion in the P-selectin active site. The synthesis and the biological activity of this series of compounds are described. Lead compounds having a greater potency than sialyl Lewis X are identified.

Testing surgical skills of obstetric and gynecologic residents in a bench laboratory setting: validity and reliability

OBJECTIVE

Resident surgical skills are acquired mainly through observing and later performing procedures in the operating room. Evaluation of surgical skills has traditionally been done through subjective faculty evaluation, a technique that has poor reliability and unknown validity. Our goal was to develop specific surgical tasks, both laparoscopic and open abdominal, that could be objectively and reliably evaluated in a bench laboratory setting.

STUDY DESIGN

The prospective development of a reliable and valid resident surgical skills test in a bench laboratory setting was our goal. A written test of surgical knowledge and 12 skills tests were administered to 36 residents. Laparoscopic bench tasks were simulated with the use of a box and camera with a video display. Six laparoscopic tasks were assessed, including placing pegs on a board, running the bowel simulation, and other tasks that involve hand-eye coordination and manual dexterity. Open abdominal skills simulated incision closure, suturing a vaginal cuff, knot tying, and using a tie on a passer. Residents were timed at each given station and were given a rating score by 2 examiners.

RESULTS

Knowledge scores showed a significant improvement by residency level. Assessment of construct validity (the ability to discriminate among residency levels) demonstrated significant differences on the rating of overall performance and individual tasks by level (determined by 1-way analysis of variance). Interrater reliability (agreement between 2 raters) with the use of intraclass correlation was 0.79 for the total score. The cost to administer the bench laboratory test was less than $50 and required 30 hours of faculty time.

CONCLUSION

The results of this study suggest that surgical bench laboratory tasks can assess residents' surgical skills with good reliability and validity on most tasks. Our previous study, which used an animal laboratory, was expensive, and the bench laboratory model may provide an alternative means to assess surgical skills.

Accompany the sick: a unique practice in Chinese hospitals by patients' relatives and friends

There is a practice commonly found in many Chinese hospitals called 'accompany the sick' (pei ban). It means that many patients' relatives or friends 'live' with patients in the hospital. Such practice can benefit patients in that the visitors are providing psychological support and carrying out some bedside nursing care to the patients. However, it also creates many problems to nurses and hospitals such as overcrowding, an over-demand of hospital resources, and maintaining quality care. There is no study of such practice. In order to gain better understanding of 'accompany the sick', its impact on nursing practice and nursing professional development, identifying the contributing factors of such practice is needed. This is an ethnographic case study of a public hospital in western China. The study has discovered a number of factors that contribute to the practice, such as the Chinese concept of duty of care, the geographic and economic situation, and the unique culture of nursing practice. This is a pilot study and the result of this study will contribute to further study in nurses' work in China.

Relationships and diseases among drug users and nonusers

Human immunodeficiency virus (HIV) and syphilis are relationship-based diseases that are typically transmitted by the cooperative activities (sex or drug injection) of two persons. A sample of 215 drug users and 52 sociodemographically matched nonusers was collected to examine the behaviors and relationships related to HIV and syphilis transmission. Results showed that, although drug users had more risk opportunities (more sex partners and, of course, more injection partners) than nonusers, actual sex risk behaviors (never using condoms) did not differ appreciably among drug users and nonusers or with opposite-sex partners and same-sex partners. The similarity of sexual risk was supported by the similar levels of syphilis between drug users and nonusers. The unique risk to drug users was drug injection, although drug users were found to engage in fewer risky injection behaviors (sharing of drug injection equipment) than the risky sexual behaviors in which all participants engaged. Although drug users interacted as frequently with partners as nonusers, nonuser relationships were longer lasting and emotionally closer.

Antiretroviral activity and safety of abacavir in combination with selected HIV-1 protease inhibitors in therapy-naive HIV-1-infected adults

OBJECTIVE

To assess antiretroviral efficacy and safety of abacavir in combination with selected HIV-1 protease inhibitors.

DESIGN

A 48-week, open-label study.

MATERIALS AND METHODS

Eighty-two antiretroviral naive HIV-1-infected adults (CD4 cell count > or = 100 cells/mm3, plasma HIV-1 RNA > or = 5,000 copies/ml) were randomly assigned to receive abacavir (300 mg twice daily) in combination with standard doses of one of five protease inhibitors: indinavir, saquinavir soft-gel, ritonavir, nelfinavir or amprenavir. Adults who met protocol-defined switch criteria at or after week 8 could modify their randomized therapy. Antiretroviral activity was assessed by the proportion of subjects with plasma HIV-1 RNA < or = 400 and < or = 50 copies/ml, and by changes in plasma HIV-1 RNA levels and CD4 cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities.

RESULTS

At week 48, the proportion of subjects in the indinavir, saquinavir, ritonavir, nelfinavir and amprenavir groups with plasma HIV-1 RNA < or = 400 copies/ml was 53, 50, 50, 41 and 56%, respectively, and the proportion with HIV-1 RNA < or = 50 copies/ml was 47, 56, 50, 47, and 44%, respectively (by intent-to-treat analysis). Median reductions from baseline in plasma HIV-1 RNA for each group ranged from 1.7 to 2.4 log10 copies/ml. The median CD4 cell count increase from baseline was 195, 131, 116, 136 and 259 cells/mm3 in the indinavir, saquinavir, ritonavir, nelfinavir, and amprenavir groups, respectively. Overall, the most common adverse events attributed to study drugs were diarrhoea, nausea, malaise/fatigue, headache and perioral paresthesia. The frequency of treatment-limiting adverse events did not differ between groups.

CONCLUSIONS

Abacavir is safe and effective when used in combination with a protease inhibitor.