Dynamics of DNA damage-induced nuclear inclusions are regulated by SUMOylation of Btn2

Spatial compartmentalization is a key facet of protein quality control that serves to store disassembled or non-native proteins until triage to the refolding or degradation machinery can occur in a regulated manner. Yeast cells sequester nuclear proteins at intranuclear quality control bodies (INQ) in response to various stresses, although the regulation of this process remains poorly understood. Here we reveal the SUMO modification of the small heat shock protein Btn2 under DNA damage and place Btn2 SUMOylation in a pathway promoting protein clearance from INQ structures. Along with other chaperones, and degradation machinery, Btn2-SUMO promotes INQ clearance from cells recovering from genotoxic stress. These data link small heat shock protein post-translational modification to the regulation of protein sequestration in the yeast nucleus.

Nuclear protein quality control in yeast: the latest INQuiries

The nucleus is a highly organized organelle with an intricate substructure of chromatin, RNAs, and proteins. This environment represents a challenge for maintaining protein quality control, since non-native proteins may interact inappropriately with other macromolecules and thus interfere with their function. Maintaining a healthy nuclear proteome becomes imperative during times of stress, such as upon DNA damage, heat shock, or starvation, when the proteome must be remodeled to effect cell survival. This is accomplished with the help of nuclear-specific chaperones, degradation pathways, and specialized structures known as protein quality control (PQC) sites that sequester proteins to help rapidly remodel the nuclear proteome. In this review, we focus on the current knowledge of PQC sites in Saccharomyces cerevisiae, particularly on a specialized nuclear PQC site called the intranuclear quality control site, a poorly understood nuclear inclusion that coordinates dynamic proteome triage decisions in yeast.

Relationship between Body Mass Index and Dental Caries in 13-15-Year-Old School Children of Government and Private Schools in Bengaluru City

Aims:

The aim of the study was to assess the correlation between body mass index (BMI) and dental caries of 13–15-years-old school children in urban Bangalore and to compare the correlation between BMI and dental decay amongst government and private school children of age group 13–15 years in Bangalore city.

Subjects and Methods:

A total of 660 students 13–15 years old were inducted in the study. According to these, 330 students from government schools and 330 students from private schools were examined. A specially designed structured questionnaire was used for compilation of data in the survey. BMI for age percentiles was deducted by weight in kilogram divided by height in meter square.

Results:

Overall a positive correlation was found between Decayed, Missing, and Filled Teeth DMFT and BMI. In government schools, Overweight children had more mean DMFT (1.43) than other BMI categories while in Private schools, At risk of overweight children had more mean DMFT (1.4) than other category of BMI children.

Conclusions:

A positive correlation was found between DMFT and BMI. In government schools, Overweight children had more mean DMFT than other BMI category while in Private schools, At risk of overweight children had more mean DMFT than other category children.

Clinical Effects of the Self-administered Subcutaneous Complement Inhibitor Zilucoplan in Patients With Moderate to Severe Generalized Myasthenia Gravis: Results of a Phase 2 Randomized, Double-Blind, Placebo-Controlled, Multicenter Clinical Trial

Question

What are the clinical effects of zilucoplan, a subcutaneously self-administered macrocyclic peptide inhibitor of complement component 5, in a broad population of patients with moderate to severe acetylcholine receptor autoantibody–positive generalized myasthenia gravis?

Findings

In a randomized, double-blind, placebo-controlled, multicenter phase 2 trial, zilucoplan yielded rapid, clinically meaningful, statistically significant, and sustained improvements in the primary and key secondary end points. Near-complete complement inhibition was associated with a faster onset and greater magnitude of benefit than submaximal complement inhibition, and favorable safety and tolerability were observed.

Meaning

The findings support a potential therapeutic role for zilucoplan in generalized myasthenia gravis and further evaluation in a phase 3 study.

Importance

Many patients with generalized myasthenia gravis (gMG) have substantial clinical disability, persistent disease burden, and adverse effects attributable to chronic immunosuppression. Therefore, there is a significant need for targeted, well-tolerated therapies with the potential to improve disease control and enhance quality of life.

Objective

To evaluate the clinical effects of zilucoplan, a subcutaneously (SC) self-administered macrocyclic peptide inhibitor of complement component 5, in a broad population of patients with moderate to severe gMG.

Design, Setting, and Participants

This randomized, double-blind, placebo-controlled phase 2 clinical trial at 25 study sites across North America recruited participants between December 2017 and August 2018. Fifty-seven patients were screened, of whom 12 did not meet inclusion criteria and 1 was lost to follow-up after randomization but before receiving study drug, resulting in a total of 44 acetylcholine receptor autoantibody (AChR-Ab)–positive patients with gMG with baseline Quantitative Myasthenia Gravis (QMG) scores of at least 12, regardless of treatment history.

Interventions

Patients were randomized 1:1:1 to a daily SC self-injection of placebo, 0.1-mg/kg zilucoplan, or 0.3-mg/kg zilucoplan for 12 weeks.

Main Outcomes and Measures

The primary and key secondary end points were the change from baseline to week 12 in QMG and MG Activities of Daily Living scores, respectively. Significance testing was prespecified at a 1-sided α of .10. Safety and tolerability were also assessed.

Results

The study of 44 patients was well balanced across the 3 treatment arms with respect to key demographic and disease-specific variables. The mean age of patients across all 3 treatment groups ranged from 45.5 to 54.6 years and most patients were white (average proportions across 3 treatment groups: 78.6%-86.7%). Clinically meaningful and statistically significant improvements in primary and key secondary efficacy end points were observed. Zilucoplan at a dose of 0.3 mg/kg SC daily resulted in a mean reduction from baseline of 6.0 points in the QMG score (placebo-corrected change, –2.8; P = .05) and 3.4 points in the MG Activities of Daily Living score (placebo-corrected change, –2.3; P = .04). Clinically meaningful and statistically significant improvements were also observed in other secondary end points, the MG Composite and MG Quality-of-Life scores. Outcomes for the 0.1-mg/kg SC daily dose were also statistically significant but slower in onset and less pronounced than with the 0.3-mg/kg dose. Rescue therapy (intravenous immunoglobulin or plasma exchange) was required in 3 of 15, 1 of 15, and 0 of 14 participants in the placebo, 0.1-mg/kg zilucoplan, and 0.3-mg/kg zilucoplan arms, respectively. Zilucoplan was observed to have a favorable safety and tolerability profile.

Conclusions and Relevance

Zilucoplan yielded rapid, meaningful, and sustained improvements over 12 weeks in a broad population of patients with moderate to severe AChR-Ab–positive gMG. Near-complete complement inhibition appeared superior to submaximal inhibition. The observed safety and tolerability profile of zilucoplan was favorable.

Trial Registration

ClinicalTrials.gov Identifier: NCT03315130.

Cdc48 regulates intranuclear quality control sequestration of the Hsh155 splicing factor in budding yeast

Cdc48 (known as VCP in mammals) is a highly conserved ATPase chaperone that plays an essential role in the assembly and disassembly of protein-DNA complexes and in degradation of misfolded proteins. We find that in Saccharomyces cerevisiae budding yeast, Cdc48 accumulates during cellular stress at intranuclear protein quality control sites (INQ). We show that Cdc48 function is required to suppress INQ formation under non-stress conditions and to promote recovery following genotoxic stress. Cdc48 physically associates with the INQ substrate and splicing factor Hsh155, and regulates its assembly with partner proteins. Accordingly, cdc48 mutants have defects in splicing and show spontaneous distribution of Hsh155 to INQ aggregates, where it is stabilized. Overall, this study shows that Cdc48 regulates deposition of proteins at INQ and suggests a previously unknown role for Cdc48 in the regulation or stabilization of splicing subcomplexes.This article has an associated First Person interview with the first author of the paper.

Inotersen: new promise for the treatment of hereditary transthyretin amyloidosis

Hereditary transthyretin amyloidosis is a fatal autosomal dominant disorder characterized by deposition of transthyretin amyloid into the peripheral nervous system, heart, kidney, and gastrointestinal tract. Previous treatments using liver transplantation and small molecule stabilizers were not effective in stopping disease progression. Inotersen, a 2'-O-methyoxyethyl-modified antisense oligonucleotide, which acts by reducing the production of transthyretin, was recently demonstrated to improve disease course and quality of life in early hereditary transthyretin amyloidosis polyneuropathy in a 15-month Phase III study.

Effect of Incorporation of Nanoclay on the Properties of Heat Cure Denture Base Material: An In vitro Study

Purpose:

The aim of the study was to evaluate the effect of incorporation of organically modified nanoclay in 1%, 3%, and 5% by weight on the flexural strength, surface hardness, and linear polymerization shrinkage of heat cure denture base material.

Materials and Methods:

One hundred and twenty specimens of heat-polymerized acrylic resin were fabricated. The specimens were divided into four groups (n = 10) coded I to IV. Group I was the control group (unmodified acrylic resin specimens). The specimens of the remaining three groups were reinforced with nanoclay (organically modified montmorillonite) nanoparticles to achieve loadings of 1%, 3%, and 5% by weight. The resulting nanocomposites were subjected to mechanical testing and were characterized using X-ray diffraction, scanning electron microscope, and transmission electron microscope.

Results:

The statistical analysis showed that there was no significant increase in flexural strength within and between the groups. The most significant increase in surface hardness was observed between Group I (control) and Group II (1% nanoclay). Linear polymerization shrinkage of the specimens showed a significant decrease in the control and all the experimental groups.

Conclusion:

Addition of 1 wt% nanoclay to polymethyl methacrylate heat cure denture base material could enhance the surface hardness and reduce the linear polymerization shrinkage of the resin. However, there was no significant increase in flexural strength of the resulting nanocomposite.

Selective defects in gene expression control genome instability in yeast splicing mutants

RNA processing mutants have been broadly implicated in genome stability, but mechanistic links are often unclear. Two predominant models have emerged: one involving changes in gene expression that perturb other genome maintenance factors and another in which genotoxic DNA:RNA hybrids, called R-loops, impair DNA replication. Here we characterize genome instability phenotypes in yeast splicing factor mutants and find that mitotic defects, and in some cases R-loop accumulation, are causes of genome instability. In both cases, alterations in gene expression, rather than direct cis effects, are likely to contribute to instability. Genome instability in splicing mutants is exacerbated by loss of the spindle-assembly checkpoint protein Mad1. Moreover, removal of the intron from the α-tubulin gene TUB1 restores genome integrity. Thus, differing penetrance and selective effects on the transcriptome can lead to a range of phenotypes in conditional mutants of the spliceosome, including multiple routes to genome instability.

Transient Telomerase Inhibition with Imetelstat Impacts DNA Damage Signals and Cell-Cycle Kinetics

Telomerase is the ribonucleoprotein reverse transcriptase that catalyzes the synthesis of telomeres at the ends of linear chromosomes and contributes to proper telomere-loop (T-loop) formation. Formation of the T-loop, an obligate step before cell division can proceed, requires the generation of a 3'-overhang on the G-rich strand of telomeric DNA via telomerase or C-strand specific nucleases. Here, it is discovered that telomerase activity is critical for efficient cell-cycle progression using transient chemical inhibition by the telomerase inhibitor, imetelstat. Telomerase inhibition changed cell cycle kinetics and increased the proportion of cells in G₂-phase, suggesting delayed clearance through this checkpoint. Investigating the possible contribution of unstructured telomere ends to these cell-cycle distribution changes, it was observed that imetelstat treatment induced γH2AX DNA damage foci in a subset of telomerase-positive cells but not telomerase-negative primary human fibroblasts. Chromatin-immunoprecipitation with γH2AX antibodies demonstrated imetelstat treatment-dependent enrichment of this DNA damage marker at telomeres. Notably, the effects of telomerase inhibition on cell cycle profile alterations were abrogated by pharmacological inhibition of the DNA-damage-repair transducer, ATM. Also, imetelstat potentiation of etoposide, a DNA-damaging drug that acts preferentially during S-G₂ phases of the cell cycle, depends on functional ATM signaling. Thus, telomerase inhibition delays the removal of ATM-dependent DNA damage signals from telomeres in telomerase-positive cancer cells and interferes with cell cycle progression through G₂Implications: This study demonstrates that telomerase activity directly facilitates the progression of the cell cycle through modulation of transient telomere dysfunction signals. Mol Cancer Res; 16(8); 1215-25. ©2018 AACR.

Protein quality control meets transcriptome remodeling under stress

To tolerate and recover from genotoxic stress cells must coordinate a range of stress response activities including cell cycle arrest, DNA repair, and remodeling of the transcriptome and proteome. The suppression of ribosome production is a key feature of many stress responses in yeast, and much is known about the dynamics of this process at the transcriptional level. In our recent study, (J Cell Biol doi: 10.1083/ jcb.201612018) we focus on the stress related dynamic behaviour of a splicing factor called Hsh155, which is a core component of the SF3B subcomplex of the U2 small nuclear ribonucleoprotein complex, homologous to human SF3B1. The disassembly from its complex and sequestration of Hsh155 into nuclear protein aggregates contributes to suppressing ribosome production post-transcriptionally by promoting intron retention in ribosomal protein gene transcripts. The relocalization of Hsh155 is facilitated by TORC1-driven transcriptional changes and molecular chaperones that recognize disassembled Hsh155, eventually aiding in efficient recovery from stress.

Selective aggregation of the splicing factor Hsh155 suppresses splicing upon genotoxic stress

Upon genotoxic stress, dynamic relocalization events control DNA repair as well as alterations of the transcriptome and proteome, enabling stress recovery. How these events may influence one another is only partly known. Beginning with a cytological screen of genome stability proteins, we find that the splicing factor Hsh155 disassembles from its partners and localizes to both intranuclear and cytoplasmic protein quality control (PQC) aggregates under alkylation stress. Aggregate sequestration of Hsh155 occurs at nuclear and then cytoplasmic sites in a manner that is regulated by molecular chaperones and requires TORC1 activity signaling through the Sfp1 transcription factor. This dynamic behavior is associated with intron retention in ribosomal protein gene transcripts, a decrease in splicing efficiency, and more rapid recovery from stress. Collectively, our analyses suggest a model in which some proteins evicted from chromatin and undergoing transcriptional remodeling during stress are targeted to PQC sites to influence gene expression changes and facilitate stress recovery.

Genome-wide bisulfite sensitivity profiling of yeast suggests bisulfite inhibits transcription

Bisulfite, in the form of sodium bisulfite or metabisulfite, is used commercially as a food preservative. Bisulfite is used in the laboratory as a single-stranded DNA mutagen in epigenomic analyses of DNA methylation. Recently it has also been used on whole yeast cells to induce mutations in exposed single-stranded regions in vivo. To understand the effects of bisulfite on live cells we conducted a genome-wide screen for bisulfite sensitive mutants in yeast. Screening the deletion mutant array, and collections of essential gene mutants we define a genetic network of bisulfite sensitive mutants. Validation of screen hits revealed hyper-sensitivity of transcription and RNA processing mutants, rather than DNA repair pathways and follow-up analyses support a role in perturbation of RNA transactions. We propose a model in which bisulfite-modified nucleotides may interfere with transcription or RNA metabolism when used in vivo.

Efficacy of Four Remineralizing Agents on Primary Teeth: In Vitro Evaluation Using Microhardness Testing and Quantitative Light-induced Fluorescence

PURPOSE

This study's purpose was to evaluate the remineralization of primary enamel using GC Tooth Mousse, Clinpro Tooth Crème, SHY-NM, and Pronamel by employing microhardness testing and quantitative light-induced fluorescence (QLF) values.

METHODS

An in vitro study was performed with 100 intact primary anterior teeth. After specimen preparation, they were subjected to baseline microhardness and QLF testing. The specimens were immersed in demineralizing solution, subjected again to microhardness and QLF testing, and divided randomly into five groups of 20 teeth: group one-control group (artificial saliva); group two-GC Tooth Mousse; group three-ClinPro tooth crème; group four-SHY-NM; and group five-Pronamel. The pastes were respectively applied for the specific group specimens for 15 consecutive days. The samples were subjected to microhardness and QLF testing.

RESULTS

The results were analyzed using analysis of variance testing. A post-hoc comparison was done using a paired t test. There were mean increases in microhardness and QLF values with all remineralizing agents. Group two showed a statistically significant increase (P<0.05) in microhardness and QLF values. Group four showed a significant increase only in microhardness values. (P<0.05).

CONCLUSION

GC Tooth Mousse and SHY-NM are promising materials for remineralizing incipient lesions in primary teeth.

CX-5461 is a DNA G-quadruplex stabilizer with selective lethality in BRCA1/2 deficient tumours

G-quadruplex DNAs form four-stranded helical structures and are proposed to play key roles in different cellular processes. Targeting G-quadruplex DNAs for cancer treatment is a very promising prospect. Here, we show that CX-5461 is a G-quadruplex stabilizer, with specific toxicity against BRCA deficiencies in cancer cells and polyclonal patient-derived xenograft models, including tumours resistant to PARP inhibition. Exposure to CX-5461, and its related drug CX-3543, blocks replication forks and induces ssDNA gaps or breaks. The BRCA and NHEJ pathways are required for the repair of CX-5461 and CX-3543-induced DNA damage and failure to do so leads to lethality. These data strengthen the concept of G4 targeting as a therapeutic approach, specifically for targeting HR and NHEJ deficient cancers and other tumours deficient for DNA damage repair. CX-5461 is now in advanced phase I clinical trial for patients with BRCA1/2 deficient tumours (Canadian trial, NCT02719977, opened May 2016).

3'-Phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1) knockdown sensitizes non-small cell lung cancer cells to DNA damaging agents

Standard treatment for advanced non-small cell lung cancer (NSCLC) with no known driver mutation is platinum-based chemotherapy, which has a response rate of only 30–33%. Through an siRNA screen, 3′-phosphoadenosine 5′-phosphosulfate (PAPS) synthase 1 (PAPSS1), an enzyme that synthesizes the biologically active form of sulfate PAPS, was identified as a novel platinum-sensitizing target in NSCLC cells. PAPSS1 knockdown in combination with low-dose (IC₁₀) cisplatin reduces clonogenicity of NSCLC cells by 98.7% (p < 0.001), increases DNA damage, and induces G1/S phase cell cycle arrest and apoptosis. PAPSS1 silencing also sensitized NSCLC cells to other DNA crosslinking agents, radiation, and topoisomerase I inhibitors, but not topoisomerase II inhibitors. Chemo-sensitization was not observed in normal epithelial cells. Knocking out the PAPSS1 homolog did not sensitize yeast to cisplatin, suggesting that sulfate bioavailability for amino acid synthesis is not the cause of sensitization to DNA damaging agents. Rather, sensitization may be due to sulfation reactions involved in blocking the action of DNA damaging agents, facilitating DNA repair, promoting cancer cell survival under therapeutic stress or reducing the bioavailability of DNA damaging agents. Our study demonstrates for the first time that PAPSS1 could be targeted to improve the activity of multiple anticancer agents used to treat NSCLC.

Metformin in obese children and adolescents: the MOCA trial

CONTEXT

Childhood obesity is increasingly associated with type 2 diabetes (T2D). Metformin reduces the risk for T2D in adult obese nondiabetic patients, but the evidence in obese children and young people is inconclusive.

OBJECTIVE

The objective of the study was to assess the effect of metformin on body mass index sd score (BMI-SDS), metabolic risk factors, and adipokines.

DESIGN

This was a prospective, randomized, double-blind, placebo-controlled trial.

SETTING

The study was conducted at six pediatric endocrine centers in the United Kingdom.

PARTICIPANTS

One hundred fifty-one obese children and young people with hyperinsulinemia and/or impaired fasting glucose or impaired glucose tolerance (metformin: 74, placebo: 77). The study was comprised of 67.5% females, 65.6% postpubertal individuals, and 23.8% British Asian or Afro-Caribbean participants. The age range was 8-18 yr, the mean age was 13.7 (SD 2.3) yr, and the mean BMI-SDS was +3.4 (SD 0.5).

INTERVENTIONS

The intervention included metformin 1 g in the morning and 500 mg in the evening vs. placebo for 6 months.

MAIN OUTCOME MEASURE

The main outcome measure was a reduction in BMI-SDS at 6 months. Secondary outcomes included insulin and glucose levels from oral glucose tolerance tests, alanine aminotransferase (ALT), and adiponectin to leptin ratio (ALR) at 3 and 6 months.

RESULTS

Metformin was associated with a significant reduction in BMI-SDS compared with placebo at 6 months [mean difference -0.1 SD (95% confidence interval -0.18 to -0.02), P = 0.02]. Significant improvements at 3 months were found in the metformin group: fasting glucose, -0.16 mmol/liter (-0.31 to -0.00), P = 0.047; ALT, 19% (5-36%), P = 0.008; and ALR, 32% (4-67%), P = 0.02.

CONCLUSIONS

Metformin therapy has a beneficial treatment effect over placebo for BMI-SDS, fasting glucose, ALT, and ALR ratio at 3 months, with changes in BMI-SDS sustained at 6 months.

Congenital adrenal hyperplasia - experience from a tertiary centre in South India

Congenital adrenal hyperplasia is a group of autosomal recessive disorders caused by enzyme deficiency which leads to defects in biosynthesis of steroid precursors. Most common is 21 hydroxylase deficiency. Clinical spectrum varies from non-classical CAH to classic CAH, and it may be simple virilising form or salt-wastinfg type. 29 patients were included in our study from January 2012 to October 2012. 76% were females. Male babies typically presented with adrenal crisis between 3(rd) to 6(th) week of life. Around 20% of females were identified and appropriately treated only after late adolescence. Short stature was seen in 1/3(rd) of patients. 1/3(rd) of patients had suppressed 17 OHP levels suggestive of over-replacement therapy which may contribute to final reduction in adult height.

Megaduodenum in a patient with acromegaly

INTRODUCTION

Acromegaly is associated with enlargement of all organs including the gastro intestinal system. However, there are no previous reports of occurrence of megaduodenum in patients with acromegaly.

DISCUSSION

We present the case of a 47 year old male who was diagnosed to have acromegaly 13 years ago and had undergone transsphenoidal surgery twice with incomplete removal of the pituitary macro-adenoma and received radiotherapy following the second surgery. Patient has been on replacement therapy for hypocortisolism, hypothyroidism and hypogonadism since 10 years. Post glucose growth hormone level continued to remain unsuppressed; however, patient never received any medical therapy for acromegaly. He was evaluated with esophago-gastro-duodenoscopy for recurrent abdominal pain and distension, which showed an elongated and tortuous megaduodenum. These findings were verified with a barium study which revealed dilated stomach, first and second part of duodenum with no evidence of a distal obstruction.

CONCLUSIONS

We report this finding in view of the rare association.

Utility of neurophysiological criteria in Guillain Barre΄ syndrome: subtype spectrum from a tertiary referral hospital in India

BACKGROUND

The Guillain Barre' syndrome (GBS) is a heterogeneous disease with various subtypes, the prevalence of which would depend on the geographic region. Recognition of these subtypes is of clinical importance since each subtype has an independent pathogenesis and different type of pathology and prognosis.

OBJECTIVES

To study the various subtypes of GBS using the various published electrophysiological criteria.

DESIGN

Retrospective descriptive study.

MATERIALS AND METHODS

In a tertiary care hospital setting, the study compared the various published criteria for demyelination in GBS. The charts of 115 consecutive patients referred for electrodiagnostic evaluation to the Electromyography laboratory between July 2000 and June 2006 were reviewed.

RESULTS

Of the 115 patients, 51 (44.4%) patients had axonal forms of GBS and 44 (38.2%) patients had acute inflammatory demyelinating polyradiculoneuropathy (AIDP). Applying the various published criteria, the number of patients categorized under the AIDP subtype ranged between 23.4% and 67.2%.

CONCLUSION

In this study 44% patients had axonal forms of the disease, 38.2% patients had AIDP subtype and 17% remained unclassified. The most sensitive criteria to identify AIDP were the criteria proposed by Albers and colleagues and the Dutch group.

The DEK oncoprotein is a Su(var) that is essential to heterochromatin integrity

Heterochromatin integrity is crucial for genome stability and regulation of gene expression, but the factors involved in mammalian heterochromatin biology are only incompletely understood. Here we identify the oncoprotein DEK, an abundant nuclear protein with a previously enigmatic in vivo function, as a Suppressor of Variegation [Su(var)] that is crucial to global heterochromatin integrity. We show that DEK interacts directly with Heterochromatin Protein 1 α (HP1α) and markedly enhances its binding to trimethylated H3K9 (H3K9me3), which is key for maintaining heterochromatic regions. Loss of Dek in Drosophila leads to a Su(var) phenotype and global reduction in heterochromatin. Thus, these findings show that DEK is a key factor in maintaining the balance between heterochromatin and euchromatin in vivo.

Antimicrobial drug resistance in Escherichia coli isolated from commercial chicken eggs in Grenada, West Indies

OBJECTIVE

To determine the antimicrobial resistance profile of Escherichia coli (E coli) isolated from the shell membrane and yolk of commercial chicken eggs in Grenada.

METHODS

A total of 450 eggs were collected from different locations including small (33.3%) and big farms (26.7%), roadside vendors (26.7%) and supermarkets (13.3%). The shell membranes and yolk were cultured separately on blood agar and McConkey Agar Escherichia coli were identified using biochemical tests and API20E strips. The isolates were tested for antimicrobial sensitivity.

RESULTS

A total of 55 E coli isolates were obtained. Of which 34 isolates were from shell membrane and 21 from yolk samples. Twenty-two of the total 34 isolates from shell membrane exhibited resistance to one or more of the antibiotics used in the study whereas 11 of the 21 yolks isolate also showed resistance to one or more of the tested antibiotics. Among the six antibiotics tested, the highest level of resistance was observed for ampicillin, 42.9 per cent and 31.8 per cent respectively for shell membrane and yolk isolates. The lowest resistance rate among all the antibiotics was observed against enrofloxacin (0%). Multi-drug resistance (resistance to > or = 3 compounds) was observed in 10.9% of the isolates.

CONCLUSIONS

This study on E coli drug resistance in commercial chicken eggs in Grenada generated baseline data indicating that chicken eggs used for food can harbour resistant E coli. A regular monitoring of commensal and clinical isolates of E coli for antibacterial resistance is warranted.

Underlying prothrombotic states in pregnancy associated cerebral venous thrombosis

BACKGROUND

The exact pathogenesis of pregnancy associated cerebral venous thrombois is still unsettled. Aims : To identify possible inherited and acquired prothrombotic risk factors and also identify the factors associated with mortality in pregnancy associated CVT.

SETTINGS AND DESIGN

Prospective cohort study to identify prothrombotic risk factors and case control study of influence of local traditional practice of puerperal water restriction on postpartum CVT.

MATERIALS AND METHODS

Consecutive patients with pregnancy associated CVT seen over a period of three years. Thrombotic workup included genetic markers, protein assays, and other factors.

STATISTICAL ANALYSIS

Univariate and chi-square analysis.

RESULTS

Of the 41 patients studied during the study period, 71% of patient had a single and 34% had multiple prothrombotic risk factors. Methylene tetrahydro-folate reductase (MTHFR) heterozygosity (19.5%) and factor V Leiden heterozygous (7.3%) were the commonest genetic markers. Hyperhomocysteinemia (34%) and elevated factor VIII levels (14.6%) were the other important risk factors. In this cohort the mortality was 17%. Mortality increased by odds of 1.3 for every additional prothrombotic marker. The factors associated with increased mortality included: status epileptics (P = 0.05, OR 13.2, 95% CI 1.002 - 173), deep venous system involvement (P = 0.016, OR 9.64, 95% CI 1.53 - 60.6), presence of midline shift (P = 0.012, OR 24.7, 95% CI 2.05 - 29.8) and diffuse cerebral edema (P = 0.006, OR 14.5, 95% CI 2.18- 96.4). The traditional practice of decrease intake of water during puerperium was significant in woman with pregnancy associated CVT when compared to control subjects (P < 0.02).

CONCLUSION

In patients with pregnancy associated CVT, prothrombotic markers can be multiple and are associated with increased odds of mortality. Deep venous system involvement, presence of midline shift and diffuse cerebral edema increased mortality. Peuperial water restriction may be a modifiable risk factor.

Treatment of acute ischemic stroke: awareness among general practitioners

For promptly referral of a patient with acute ischemic stroke (AIS) for possible thrombolysis, general practitioners (GPs) need to equipped with the advanced knowledge of AIS treatment. We assessed the knowledge regarding treatment of AIS among GPs practicing in and around a quaternary care teaching hospital in south India. A total of 109 GPs who attend to medical emergencies were interviewed using a standard questionnaire. Of the 109 GPs interviewed, 54% felt that tissue plasminogen activator (tPA) can be used in the treating AIS, but only 24% had chosen tPA as the best treatment option and 22% opted for other agents like citicholine or edavarone. Only 17% were aware that tPA should be given within 3 h. and 35% felt that intra-arterial thrombolysis as a treatment option.. Only 30% felt the need for good sugar control and 37% wanted aggressive lowering of blood pressure. Majority of GPs are not clear about beneficial effects of thrombolysis and are not updated regarding BP and sugar control in the setting of AIS.

Atrioventricular sequential pacing in cardiac amyloidosis: an acute Doppler echocardiographic and catheterization hemodynamic study

BACKGROUND AND HYPOTHESIS

Congestive heart failure due to cardiac amyloidosis is often refractory to conventional medical management and is associated with a high mortality rate. Recently, dual-chamber pacemaker implantation has been proposed as a therapeutic option in the management of patients with certain forms of cardiomyopathy with persistent heart failure symptoms, despite optimal medical therapy. The present study evaluates the acute hemodynamic response to atrioventricular (AV) pacing in patients with cardiac amyloidosis who presented with refractory heart failure symptoms.

METHODS

Three patients with medically refractory heart failure due to cardiac involvement of amyloidosis underwent a simultaneous cardiac catheterization/Doppler echocardiography study with acute AV sequential pacing at varying AV intervals.

RESULTS

During pacing at various AV intervals, all patients showed an increased in their filling pressures and either no change or decline in their cardiac index.

CONCLUSION

The current study demonstrates an absence of acute hemodynamic with AV sequential pacing in patients with amyloid heart disease and medically refractory heart failure symptoms.

Pseudotumor--like presentation of neurobrucellosis

Brucellosis is bacterial zoonoses. In endemic areas brucellosis can present with clinical features of nearly any neurological illness. Meningitic presentation is most common, with patient presenting with either acute or chronic meningitis. Pseudotumor--like presentation is also documented and accounts for only 4% of cases of neurobrucellosis. Here we are documenting a case of neurobrucellosis with presentation similar to pseudotumor cerebri but with abnormal CSF. This highlights the fact that being a potentially treatable condition brucellosis should always come in the differential diagnosis of neurotuberculosis especially if there are atypical features e.g. pseudotumor presentation with abnormal CSF.

Heterocyclic system containing bridgehead nitrogen atom: synthesis and pharmacological activities of some substituted 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles

Several 3,6-disubstituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadizoles were prepared by the condensation of 4-amino-3-aryl/aralkyl substituted-5-mercapto-1,2,4-triazoles 3(a-c) with various substituted aromatic/hetero aromatic acids through a single step reaction. Elemental analysis, IR, 1H NMR and mass spectral data confirmed the structure of the newly synthesized compounds. Synthesized triazolo thiadiazoles investigated for their antibacterial, antifungal, anti-inflammatory and analgesic activities. Some of the tested compounds showed moderate antimicrobial activity against various tested bacterial and fungal strains. None of the synthesized compounds have significant anti-inflammatory and analgesic activities.

Congestive heart failure in a male with "carcinoma tongue": a case of mistaken identity

We present a case of primary amyloidosis with macroglossia and restrictive cardiomopathy, that was mistakenly diagnosed as carcinoma of the tongue. He had characteristic echocardiographic findings, and bone marrow plasmacytosis but with normal serum electrophoresis and no Bence Jones proteins in the urine.

Hemicraniectomy for large middle cerebral artery territory infarction: outcome in 19 patients

BACKGROUND

Large space-occupying middle cerebral artery infarction accounts for 10-15% of all supratentorial infarctions and carries a mortality of 50% to 80%. Hemicraniectomy may be useful when optimal medical management has failed.

METHODS

Between June 1997 and June 2000, 19 patients who fulfilled the clinical and imaging criteria for large middle cerebral artery infarction underwent hemicraniectomy because of impending herniation despite best medical therapy. The National Institute of Health Stroke Scale (NIHSS) assessed neurological status on admission and at one week after surgery. At 3 month follow up, The Barthel Index (BI) and Rankin Scale (RS) were used to assess the functional outcome among survivors.

RESULTS

There were 15 males and 4 females with a mean age of 46.5 years (range 27-76 years). Ten patients (53%) had dominant hemisphere stroke. The mean interval between stroke onset and surgery was 60.3 hours (range 20-103 hours). The mean NIHSS score before surgery was 20.5 (range 17-26) and 10.5 (range 6-22) after surgery. One patient (5.2%) died due to post-operative meningitis. At follow up, mean BI was 56.4 (range 25-90) and RS revealed severe handicap in 4 patients (21%). Patients under 50 years of age had a significantly better outcome with mean BI of 60.7 as compared to only 41.3 (p=<0.048) in older patients. Speech function, especially comprehension improved in all patients with dominant hemisphere infarction.

CONCLUSION

These findings add to previous studies suggesting hemicraniectomy may be a useful procedure in patients with large middle cerebral artery territory infarction. The functional outcome is good in younger patients. A randomised controlled trial is required to substantiate these findings.

Non-Hodgkin's lymphoma of the brainstem with atrial septal mass

Simultaneous occurrence of cardiac and central nervous system tumors have been rarely reported. A 23 years male presented to us with right cerebello-pontine (CP) angle symptoms and signs. Cranial imaging showed a mass lesion in the right pons infiltrating into the right and middle cerebellar peduncles. There was also a cardiac-atrial septal mass. The brainstem lesion was found to be a non-Hodgkin's lymphoma where as the cardiac lesion was not accessible. Central nervous system lymphomas are reported rarely and the prognosis is poor. The chances of the cardiac lesion in this patient also being a lymphoma are high, as it was a infiltrative cardiac mass, infiltrating the atrial septum.

Comparative outcomes of percutaneous coronary interventions in diabetics vs non-diabetics with prior coronary artery bypass grafting

AIMS

To determine the influence of diabetes on outcome after percutaneous coronary intervention in patients with prior coronary artery bypass grafting.

METHODS AND RESULTS

Patients with prior coronary artery bypass grafting undergoing percutaneous coronary intervention from 1 January 1996, to 31 August 2000, were divided into two groups based on whether or not they had diabetes, excluding patients with acute infarction or shock. Cox proportional hazards models were utilized to estimate the association between diabetes and adverse events. One thousand one hundred and fifty-three post-coronary artery bypass grafting percutaneous coronary intervention patients were identified (326 diabetics and 827 non-diabetics). Diabetics were younger, more likely to have hypertension, heart failure, and lower ejection fraction. Procedural characteristics and angiographic and procedural success rates were similar. Diabetes was associated with increased mortality (hazard ratio 1.58, 95% confidence intervals 1.10-2.27). Diabetes did not have a significant effect on mortality in patients treated for single-territory coronary disease (hazard ratio 1.44, 95% confidence intervals 0.69-3.02), but did in patients with multi-territory disease (hazard ratio 1.79, 95% confidence intervals 1.16-2.76). However, in diabetics with multi-territory disease who were completely revascularized with percutaneous coronary intervention, mortality was comparable to non-diabetics (hazard ratio 1.32, 95% confidence intervals 0.57-3.03).

CONCLUSION

Among percutaneous coronary intervention patients with prior coronary artery bypass grafting, diabetes portends an adverse prognosis.

Gallbladder disorders and type 2 diabetes mellitus--a clinic-based study

AIMS OF THE STUDY

To study the prevalence of gallbladder disorders in type 2 diabetic patients and their correlation with patient factors like age, sex, weight, duration of diabetes and autonomic neuropathy.

METHODOLOGY

Fifty type 2 diabetic patients and 30 healthy controls underwent realtime ultrasonography to study the prevalence of gallbladder disorders. The fasting gallbladder volume and contraction 60 minutes after a fatty meal of the diabetic subjects were compared with 30 age and sex matched healthy volunteers. The age, sex, weight, duration of diabetes, autonomic neuropathy, control of diabetes were correlated to the prevalence of gallbladder disorders in diabetic patients.

RESULTS

32% of the diabetic patients had ultrasonographic evidence of gallstones, as compared to 6.7% in healthy subjects. 73.7% of the diabetic patients with gallbladder disorders were females. Mean fasting gallbladder volume was significantly increased in diabetic patients (26.2 cm3) as compared to non-diabetic healthy subjects (15.8 cm3). Further mean fasting gallbladder volume of diabetic patients with gallbladder disorder (28.1 cm3) was found to be significantly larger than that of those patients without gallbladder disorder (24.6 cm3). Mean percentage of contractions of gallbladder 60 min after fatty meal was reduced in diabetic patients (53.1%) and it was observed to be further reduced in the patients with gallbladder disorder (41.8%). Mean fasting gallbladder volume was larger in diabetic subjects with autonomic neuropathy, than those without. However, difference in mean percentage contraction of gallbladder 60 min after fatty meal was not statistically significant. Mean duration of diabetes was significantly longer in diabetic patients with gallbladder disorder.

CONCLUSIONS

We conclude that type 2 diabetic patients have increased prevalence of gallbladder disorder which can only partially be explained by autonomic neuropathy leading, to increased fasting volume. Factors like decreased cholecystokinin or decreased sensitivity of the smooth muscle of gallbladder to normal level of cholecystokinin need to be studied.

Early coronary angiography improves long-term survival in unstable angina

BACKGROUND

The role of early coronary angiography in the evaluation of patients with unstable angina has been controversial. This study was designed to determine the effect of early coronary angiography on long-term survival in patients with unstable angina.

METHODS

We reviewed the Olmsted County Acute Chest Pain Database, a population-based epidemiologic registry that includes all patients residing within Olmsted County who were seen for emergency department evaluation of acute chest pain from 1985 to 1992. Patients with symptoms consistent with myocardial ischemia qualifying as unstable angina were classified as undergoing early (</=7 days of index presentation) angiography or not.

RESULTS

A total of 2264 patients with symptoms consistent with unstable angina were identified with a mean duration of follow-up of 6 years; 892 underwent early angiography. Early angiography patients were younger; less likely to have heart failure; more likely to be male, hypercholesterolemic, and smokers; had prior coronary revascularization; and had a myocardial infarction at the index presentation. After baseline differences were controlled, early angiography was associated with a reduction in all-cause long-term mortality (relative risk 0.63, 95% CI 0.53-0.74). Patients at intermediate or high risk for death or myocardial infarction at presentation were most likely to benefit from early angiography.

CONCLUSION

Early angiography in the evaluation of patients with unstable angina was associated with a reduction in all-cause mortality, particularly in intermediate- and high-risk patients, in this retrospective population-based study.

Ankle brachial index as a predictor of generalized atherosclerosis

OBJECTIVE

To assess ankle brachial index (ABI) as a screening method to target subclinical atherosclerosis in middle aged individuals.

MATERIAL AND METHODS

Total 160 patients over the age of 40 years were included in the study for a period of 16 months. Their ABI was determined either by colour Doppler method (30 patients) and/or sphygmomanometry (all 160 patients). A value of < 0.9 was taken as cutoff point for significant stenosis.

RESULTS

Total 69 patients out of total of 160 had significantly low ABI value (43.12%) which shows that there is a very high incidence of low ABI in the community. Overall > 50% of the patients were largely asymptomatic and had presence of two or more risk factors. ABI < 0.9 was a good screening test to detect such individuals at an earlier stage (sub-clinical).

CONCLUSION

A significantly low (< 0.9) ABI value can detect subclinical atherosclerotic vascular involvement and predict future occurrence of preventable major vascular event.

Primary percutaneous coronary interventions in patients with acute myocardial infarction and prior coronary artery bypass grafting

BACKGROUND

The outcome of patients with previous coronary artery bypass grafting (CABG) undergoing primary percutaneous coronary intervention (PCI) for the treatment of acute myocardial infarction (AMI) is unclear. We sought to assess the outcome of patients with prior CABG undergoing primary PCI for the treatment of AMI.

METHODS AND RESULTS

Between 1991 and 1997, 1072 patients with AMI underwent primary PCI without antecedent thrombolytic therapy at the Mayo Clinic. There were 128 patients with previous CABG and 944 without previous CABG. Patients with previous CABG were further subdivided according to the treated vessel: native vessels (n = 65) and bypass graft (n = 63). Clinical and angiographic characteristics and 30-day and 1-year outcomes were evaluated. Patients with previous CABG were significantly older and had a higher incidence of diabetes, hypertension, and hypercholesterolemia. They had a lower left ventricular ejection fraction and were also more likely to have congestive heart failure. After 1 year of follow-up, adverse cardiac events (death, MI, CABG, or repeat PCI) were significantly greater in patients with prior CABG (49.2% vs 35.9%, P =.04). With use of multivariate logistic regression analysis to adjust for differences in baseline characteristics, the treatment of vein graft was independently associated with adverse cardiac events (relative risk 1.48 [95% confidence interval 1.07-2.03], P =.02), but a history of prior CABG itself was not (relative risk 1.22 [95% confidence interval 0.96-1.56], P =.11).

CONCLUSIONS

Primary PCI for AMI in patients with previous CABG is associated with higher adverse events largely attributable to adverse baseline clinical characteristics and the treatment of a vein graft.

Does the presence of thrombus seen on a coronary angiogram affect the outcome after percutaneous coronary angioplasty? An Angiographic Trials Pool data experience

OBJECTIVES

This study aimed to determine whether pre-existing angiographic thrombus was associated with adverse in-hospital and six-month outcomes after percutaneous coronary interventions.

BACKGROUND

There are conflicting data about whether pre-existing thrombus is an independent predictor of adverse in-hospital and short-term outcome after coronary interventions.

METHODS

The Angiographic Trials Pool, a data set derived from eight prospective randomized trials, was analyzed. The study population consisted of 7,917 patients who underwent coronary interventions between 1986 and 1995. Two trials were excluded because they did not collect information regarding thrombus. Patients from the other six trials were divided on the basis of the presence or absence of thrombus.

RESULTS

In patients with (n = 2,752) and without (5,165) thrombus, in-hospital mortality following angioplasty was low (0.8 vs. 0.6%, p = 0.207). Several adverse outcomes were higher in patients with thrombus: death/myocardial infarction (8.4 vs. 5.5%, p < or = 0.001), in-hospital abrupt closure (5.9 vs. 3.9%, p < or = 0.001) and an in-hospital composite of death, myocardial infarction and/or repeat revascularization (15.4 vs. 11.2%, p < or = 0.001). Six-month mortality was low and comparable between the two groups (2.1 vs. 1.8%, p = 0.34), but the incidence of six-month death/myocardial infarction was higher in patients with thrombus (11.7 vs. 8.7%, p < or = 0.0001).

CONCLUSIONS

Percutaneous coronary angioplasty can be performed with low mortality in patients with pre-existing thrombus, although these patients are at higher risk of in-hospital and six-month death/myocardial infarction. Continued efforts are required to optimize the outcome in these high risk patients.

Clinical risk stratification correlates with the angiographic extent of coronary artery disease in unstable angina

OBJECTIVES

We sought to determine whether clinical risk stratification correlates with the angiographic extent of coronary artery disease (CAD) in patient with unstable angina.

BACKGROUND

The Agency for Health Care Policy and Research (AHCPR) guidelines stratify patients with unstable angina according to short-term risk of myocardial infarction or death. Whether these guidelines are useful in predicting the extent of CAD is unknown.

METHODS

All residents of Olmsted County, Minnesota, undergoing emergency department evaluation from January 1, 1985 through December 31, 1992 for unstable angina without a history of prior coronary artery bypass grafting, and who underwent early angiography (within seven days of presentation) were classified into low, intermediate and high risk subgroups based on AHCPR criteria.

RESULTS

Seven hundred ninety-five patients underwent early angiography: 159 high risk, 572 intermediate risk and 64 low risk patients. Logistic regression analysis demonstrated that low risk patients had a greater likelihood of normal or mild CAD relative to intermediate risk (odds ratio [OR], 4.67; 95% confidence interval [CI], 2.70-8.06; p < 0.001) and high risk (OR, 11.1; 95% CI, 5.71-22.2; p < 0.001). Significant 1-, 2-, 3-vessel coronary disease or left main coronary disease was more likely in high relative to low risk (OR, 8.09; 95% CI, 4.22-15.5; p < 0.001), intermediate relative to low risk (OR, 4.11; 95% CI, 2.34-7.22; p < 0.001), and high relative to intermediate risk (OR, 1.97; 95% CI, 1.31-2.96; p = 0.0012).

CONCLUSIONS

Among patients with unstable angina undergoing early coronary angiography, risk stratification according to the AHCPR guidelines correlates with the angiographic extent of CAD.

Evaluation of long-term survival after successful percutaneous coronary intervention among patients with chronic renal failure

We studied the long-term outcomes after percutaneous coronary intervention in dialysis patients and in patients with chronic renal failure (CRF) (serum creatinine > or = 3.0 mg/dl). All-cause mortality at 1 year was 2.9% for the control group, 16.2% for the group with CRF, and 14.1% for dialysis patients. Cardiac mortality at 1 year was 1.9% for ther control group, 15.2% for the group with CRF, and 10.0% for dialysis patients.

Altered effects of potassium channel modulation in the coronary circulation in experimental hypercholesterolemia

OBJECTIVE

To evaluate the role of potassium channels in the regulation of coronary hemodynamics in experimental hypercholesterolemia.

BACKGROUND

Potassium (K(+)) channels play an important role in coronary vasoregulation. It has previously been demonstrated that experimental hypercholesterolemia is associated with altered coronary vasomotion; however, the role of K(+) channels in modulating coronary blood flow in this pathophysiologic state has not been evaluated.

METHODS AND RESULTS

Pinacidil (group 1, n=5) at 2 microg/kg per min, glibenclamide (group 2, n=5), or N-monomethyl-L-arginine (LNMMA) (group 3, n=4) at 50 microg/kg per min were infused into the left anterior descending artery of pigs prior to and following 10 weeks of 2% cholesterol diet. After 10 weeks of cholesterol feeding, intracoronary pinacidil resulted in a significant increase in coronary blood flow (CBF) and coronary artery diameter (CAD) compared to the normolipidemic state (111+/-10 versus 59+/-12%, and 6+/-1.1 versus 2.7+/-1.0%, respectively, P<0.05 for both comparisons), whereas intracoronary glibenclamide resulted in a significant decrease in CBF and CAD compared to the normolipidemic state (-17+/-5 versus 5+/-6%, and -0.8+/-1.4 versus 3.6+/-1.6%, respectively, P<0.05 for both comparisons). The effect of intracoronary LNMMA on CBF and CAD was significantly attenuated after 10 weeks of cholesterol feeding as compared to the normolipidemic state (-47+/-5.4 versus -0.8+/-6.8%, and -19.4+/-5.7 versus -2.3+/-3.3%, respectively, P<0.05 for both comparisons). Furthermore, pretreatment with intracoronary LNMMA did not alter the CBF response to pinacidil in normal pigs (group 4, n=4) (57.4+/-19 versus 59+/-12%, P=NS).

CONCLUSIONS

The current study demonstrates an enhanced effect of coronary K(+) channel modulation and confirms the attenuated basal NO activity previously reported in experimental hypercholesterolemia. Acute withdrawal of basal NO activity alone, however, does not explain the enhanced effect of coronary K(+) channel modulation. These findings underscore the importance of the K(+) channel pathway in the regulation of coronary vasomotor tone in pathophysiologic states.

Increased coronary effects of stimulation of endothelin-B receptor in experimental hypercholesterolemia

BACKGROUND

Vasoconstriction in response to endothelin-1 has been shown to be primarily related to its effects on the endothelin-A receptor. Experimental hypercholesterolemia is associated with an increase in coronary vasoconstrictor response to endothelin-1 in vivo, although the relative contributions of subtypes of endothelin receptor in this model remain unknown.

OBJECTIVE

To test the hypothesis that there is an increase in coronary vasoconstriction in response to stimulation of endothelin-B receptor in hypercholesterolemia, which might be related to attenuation of activity of endothelin-derived relaxing factor.

METHODS

We infused 5 ng/kg/min sarafotoxin, a specific endothelin-B receptor agonist, or 50 micrograms/kg/min NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthase, into the left anterior descending coronary arteries of pigs before and after feeding them a cholesterol-rich diet for 10 weeks.

RESULTS

There was a significant increase in serum level of cholesterol. After 10 weeks, infusion of sarafotoxin resulted in an accentuated decrease in coronary blood flow (CBF) compared with baseline (decreases by 60 +/- 7 versus 34 +/- 6%, P < 0.05). There was no significant difference between the effects on diameter of coronary arteries for the two time periods. The effect of L-NMMA on CBF was attenuated after 10 weeks (by 5 +/- 10.1 versus 45.6 +/- 4.7%, P < 0.05). Endothelin-receptor status of epicardial coronary arteries remained unchanged. Sarafotoxin and L-NMMA were co-infused at the above-mentioned doses into normolipidemic animals; the decrease in CBF in response to this co-infusion was comparable to the decrease observed with sarafotoxin alone in hypercholesterolemic animals (decreases of 67 +/- 5 versus 60 +/- 7, NS).

CONCLUSIONS

The present results demonstrate that selective stimulation of the endothelin-B receptor increases coronary vasoconstriction in experimental hypercholesterolemia, primarily at the level of the microvasculature. These findings may be related to the attenuation of activity of endothelin-derived relaxing factor in this model, and support the hypothesis that endothelin-B receptor plays a role in the regulation of coronary vascular tone in pathophysiologic states.

Effect of abciximab on late adverse events in patients with diabetes mellitus undergoing stent implantation

Percutaneous coronary intervention (PCI) in patients with diabetes mellitus (DM) is associated with higher rates of adverse cardiac events. Recent data suggest that adverse events are reduced in DM after PCI using stents with abciximab. We performed a retrospective analysis of a prospective PCI registry for all patients with DM who underwent stent placement at the Mayo Clinic from 1995 to 1997 (n = 570), and divided them into 2 groups based on whether abciximab was administered. Characterization and comparison of the clinical and angiographic variables, procedural outcomes, and short- and long-term event rates between groups was performed. The baseline clinical characteristics of the groups were similar, but patients treated with abciximab were more likely to be men with a lower left ventricular ejection fraction. Patients treated with abciximab had more multivessel intervention, saphenous vein graft intervention, and thrombus before intervention. The 30-day mortality rate (0.6% vs 3.0%, p = 0.03) and repeat PCI (0% vs 1.1%, p = 0.03) was lower in patients treated with abciximab. The 30-day rates of bypass surgery, myocardial infarction (MI), and a composite of death, MI, and revascularization were similar. The 1-year event rates did not differ significantly between patients taking and not taking abciximab for the end points of death (8.9% vs 8.8%, p = 0.97), MI (13.3% vs 11.4%, p = 0.57), bypass surgery (10.3% vs 6.2%, p = 0.20), repeat PCI (14.7% vs 15.9%, p = 0.76), and a composite of death, MI, and revascularization (30.4% vs 26.7%, p = 0.43). After adjusting for baseline variables, abciximab did not influence the occurrence of late adverse events.

Comparison of percutaneous interventions for unstable angina pectoris in patients with and without previous coronary artery bypass grafting

An increasing number of patients who have undergone previous coronary artery bypass grafting (CABG) are referred for percutaneous coronary revascularization. We identified patients who underwent percutaneous intervention for unstable angina from 1990 to 1998 at our institution and assigned them into 2 groups based on whether or not they had undergone previous CABG. There were 1,431 patients with and 4,629 patients without previous CABG. Previous CABG patients were older, had more atherosclerotic risk factors, more heart failure, lower ejection fraction, more multivessel disease, more multilesion treatment, more complex lesions, and less complete revascularization. Adjusting for baseline differences, previous CABG was associated with worse long-term mortality (RR 1.47, 95% confidence intervals [CI] 1.22 to 1.77, p < 0.001) and death, myocardial infarction, and/or revascularization (RR 1.16, 95% CI 1.04 to 1.30, p = 0.01); treatment of native lesions in patients with previous CABG versus treatment of vein graft lesions was associated with a reduction in this composite end point (RR 0.75, 95% CI 0.65 to 0.87, p < 0.001). Post-CABG patients treated between 1995 and 1998 had lower long-term mortality (RR 0.76, 95% CI 0.59 to 0.99, p = 0.04) and death, myocardial infarction, and/or revascularization (RR 0.76, 95% CI 0.66 to 0.88, p < 0.001) compared with those treated between 1990 and 1994. Thus, in patients with unstable angina referred for percutaneous revascularization, previous CABG is associated with reduced event-free survival, although the outcome of post-CABG patients treated from 1995 to 1998 is superior to that observed in patients treated from 1990 to 1994. In patients who underwent previous CABG, treatment of native lesions affords better long-term outcome than vein graft intervention.