Biochemical markers of ischaemia for the early identification of acute myocardial infarction without St segment elevation

Blood was collected on admission and after 1-2 h in 130 consecutive patients admitted with typical chest pain in order to assess the capacity of myoglobin, fatty-acid-binding protein (FABP), CK-MB mass, and troponin I (TnI) in the early identification of acute myocardial infarction (AMI) without ST elevation. Using the maximum value within 6 h of onset of symptoms, AMI was detected with a 90-95% sensitivity and a 81-94% specificity by FABP at a cut-off level 8-12 midrog/l, or 81-86% and 89-93%, respectively, by myoglobin at a cut-off level 70-90 microg/l. CK-MB mass and TnI had low sensitivity, albeit very high specificity. As almost all AMI patients were identified within 6 h, serial measurements of FABP or myoglobin ruled out AMI with a very high degree of certainty. Due to the low prevalence of AMI (16%), the positive predictive values were modest (47-73%), yet increasing the probability of AMI by a factor 3-4. Myoglobin and FABP are very useful markers in the early triage of chest pain patients.

Specific factors predict the response to pulsatile gonadotropin-releasing hormone therapy in polycystic ovarian syndrome

Ovulation induction is particularly challenging in patients with polycystic ovarian syndrome (PCOS) and may be complicated by multifollicular development. Pulsatile GnRH stimulates monofollicular development in women with anovulatory infertility; however, ovulation rates are considerably lower in the subgroup of patients with PCOS. The aim of this retrospective study was to determine specific hormonal, metabolic, and ovarian morphological characteristics that predict an ovulatory response to pulsatile GnRH therapy in patients with PCOS. Subjects with PCOS were defined by chronic amenorrhea or oligomenorrhea and clinical and/or biochemical hyperandrogenism in the absence of an adrenal or pituitary disorder. At baseline, gonadotropin dynamics were assessed by 10-min blood sampling, insulin resistance by fasting insulin levels, ovarian morphology by transvaginal ultrasound, and androgen production by total testosterone levels. Intravenous pulsatile GnRH was then administered. During GnRH stimulation, daily blood samples were analyzed for gonadotropins, estradiol (E(2)), progesterone, inhibin B, and androgen levels, and serial ultrasounds were performed. Forty-one women with PCOS underwent a total of 144 ovulation induction cycles with pulsatile GnRH. Fifty-six percent of patients ovulated with 40% of ovulatory patients achieving pregnancy. Among the baseline characteristics, ovulatory cycles were associated with lower body mass index (P < 0.05), lower fasting insulin (P = 0.02), lower 17-hydroxyprogesterone and testosterone responses to hCG (P < 0.03) and higher FSH (P < 0.05). In the first week of pulsatile GnRH treatment, E(2) and the size of the largest follicle were higher (P < 0.03), whereas androstenedione was lower (P < 0.01) in ovulatory compared with anovulatory patients. Estradiol levels of 230 pg/mL (844 pmol/L) or more and androstenedione levels of 2.5 ng/mL (8.7 nmol/L) or less on day 4 and follicle diameter of 11 mm or more by day 7 of pulsatile GnRH treatment had positive predictive values for ovulation of 86.4%, 88.4%, and 99.6%, respectively. Ovulatory patients who conceived had lower free testosterone levels at baseline (P < 0.04). In conclusion, pulsatile GnRH is an effective and safe method of ovulation induction in a subset of patients with PCOS. Patient characteristics associated with successful ovulation in response to pulsatile GnRH include lower body mass index and fasting insulin levels, lower androgen response to hCG, and higher baseline FSH. In ovulatory patients, high free testosterone is negatively associated with pregnancy. A trial of pulsatile GnRH therapy may be useful in all PCOS patients, as E(2) and androstenedione levels on day 4 or follicle diameter on day 7 of therapy are highly predictive of the ovulatory response in this group of patients.

A technical approach for optimizing surveillance of patients with unstable coronary syndromes: continuous vectorcardiography ischemic monitoring

Continuous vectorcardiography ischemic monitoring (VCG) is a noninvasive technique which has contributed much to our understanding of the dynamics of acute coronary syndromes. For risk assessment of patients with unstable angina pectoris or non-Q-wave myocardial infarction, VCG shows important prognostic power which is further enhanced by its combination with the measurement of highly sensitive and specific biochemical markers of myocardial injury. VCG surveillance after revascularization therapy of Q-wave myocardial infarction is widely accepted because of its potential of assessing vessel patency, of estimating infarct size, and of revealing residual myocardial ischemia. Valuable prognostic information is available in real time with VCG, and treatment strategies may be based upon more reliable grounds. In this survey, the VCG technique is presented together with the most frequently used vectorcardiographic variables. Further, the use of the method for risk stratification of patients with unstable coronary syndromes is also described.

Obstacles to residents' conducting research and predictors of publication

Internal medicine residents at one school identified barriers to and predictors of publishing their research. Insufficient time was the key obstacle to completing research. Residents with previous research experience, senior residents, and men were more likely to publish.

Hyperkinetic movement disorder in an 11-year-old child treated with bilateral pallidal stimulators

Pallidal stimulation is widely used in the treatment of movement disorder in adults but is less well reported in the treatment of dystonia in children. Despite inconsistent results in the past, its use in dystonia in Parkinson's disease is again attracting interest with promising results. Bilateral as well as unilateral pallidotomies have been performed and are felt to be required in some cases of dystonia. Use of depth electrodes to provide long-term electrical stimulation to pallidum and other basal ganglia structures has recently become more widespread. This technique is felt to have a lower morbidity, especially in bilateral procedures. Here we present the case of an 11-year-old boy with severe hyperkinetic movement disorder who showed sustained improvement after bilateral pallidal stimulation implantation.

Determination of optimal peat type to potentially capture copper and cadmium from solution

The focus of this study was to determine the optimum type of peat for application as a medium to capture dissolved metals from aqueous solution. Seventeen media were examined, including eleven Irish peat samples from various locations and stages in processing, a Northern Ireland lignite, peat and lignite chars, a commercial-grade bone char, and two commercial-grade granular activated carbons. Considerable variation in sorption capacity was found with a ratio of 20:1 between the best-performing (bone char) and the poorest-performing (peat char) samples. Among the 14 varieties of peat, the best-performing sample outperformed the commonly investigated sphagnum moss by a ratio of 4:1. A correlation has been established between cation exchange capacity, the presence of adsorbed calcium, and the uptake capacity of different peats. This correlation will be a valuable tool in choosing peat type for filter media for metals removal applications.

Clinical implications of rhinoceros reproductive tract anatomy and histology

Reproductive tracts or tissues from five male black rhinoceroses (Diceros bicornis), two male white rhinoceroses (Ceratotherium simum), two male one-horned Asian rhinoceroses (Rhinoceros unicornis), seven female black rhinoceroses, and six female white rhinoceroses from multiple institutions were examined to characterize their anatomy and histology. Some observations and measurements were obtained from in situ tracts of intact animals before or during necropsy. Formalin-fixed tissues were dissected and examined histologically. Retrospective reproductive data from each rhinoceros was obtained from the institutions of origin. Reproductive histology of these species was similar to that of other mammals. Male accessory gland structure varied among species, and the Asian rhinoceros epididymis was more loosely attached and had larger duct diameters than did the epididymides of the African species. Although histology was typically mammalian, rhinoceros reproductive morphology combined characteristics of several different mammals. Defining this unique morphology of rhinoceroses may help in understanding their reproductive physiology and will effect the development of appropriate reproductive techniques.

Early reperfusion assessment and repeated thrombolysis in acute myocardial infarction estimated by repeated standard electrocardiography. A randomised, double-blind, placebo-controlled pilot study

Thrombolytic therapy with streptokinase (SK) in acute myocardial infarction (AMI) does not result in early reperfusion in approximately 25% of patients. We hypothesized that early repeated thrombolysis with rt-PA in patients with early failed reperfusion would result in myocardial reperfusion. Fifty-nine AMI patients with a symptom delay of <6 h, treated with SK were included. ECG was taken on admission and after 90 and 180 min. An ST recovery of > or =25% at 90 min was interpreted as successful reperfusion. Sixteen patients had failed reperfusion at 90 min and were randomized to repeated thrombolysis with rt-PA or placebo. At 180 min from SK start, ST recovery was higher in the placebo group than in the rt-PA group (71 vs. 40%, p = 0.05). No serious bleeding complications were observed. Due to the limited sample size it was not possible to draw prominent conclusions.

Evaluating the efficacy of amikacin in low-clearance unilamellar liposomes in a s. Aureus local infection model

Traditional therapies for Staphylococcal infections such as osteomyelitis or localized abscesses have a difficult time penetrating into tissue sites. To effectively ameliorate these infections, prolonged therapy and/or high doses of antibiotics are frequently required. Aminoglycosides, such as amikacin, are not routinely utilized for treating local infections due to poor efficacy associated with ineffective tissue penetration, toxicity, and poor penetration in an acid millieu. We postulated that a formulation of amikacin in small unilamellar liposomes might readily be engulfed by inflammatory macrophages facilitating drug delivery to the site of infection. This increased drug load to the site of bacterial infection may result in enhanced bactericidal action compared to conventional aminoglycosides. Tissue drug concentrations were determined for liposomal amikacin (L-AN) and conventional amikacin (AN). Plasma amikacin levels were determined for L-AN. The L-AN was very effective at concentrating at the site of infection compared to AN. Following confirmation of adequate tissue drug levels, a rodent subcutaneous abscess infection using S. aureus as the bacterial challenge agent was evaluated. Sprague-Dawley rats were intravenously administered L-AN every other day due to its prolonged half-life, while the comparator agent, AN, was administered daily. Abscess size, weights, severity, histology, and tissue colony counts were examined. In efficacy studies, L-AN was superior to AN in reducing colony counts.

Antibiotic resistance as a stress response: complete sequencing of a large number of chromosomal loci in Staphylococcus aureus strain COL that impact on the expression of resistance to methicillin

Tn551 inactivation has identified several determinants--fem or auxiliary genes--that, in addition to the mecA gene, are also critical for the expression of high-level and homogeneous resistance to methicillin. Genetic and/or biochemical analysis has shown that of the nearly dozen aux mutations described so far most are in genes involved in cell wall synthesis (murE, pbp2, glmM, glnR, femA/B, llm, etc.) or in complex regulatory functions (sigmaB), suggesting that optimal expression of resistance may involve the cooperative functioning of a number of genes in cell wall metabolism as well as stress response. The exact mechanism of these functions is not known. In an attempt to explore this unusual aspect of methicillin resistance more fully, a Tn551 transposon library, constructed in the background of the highly and homogeneously methicillin-resistant Staphylococcus aureus strain COL, was screened for all independent insertional mutants in which the level of methicillin resistance of the parental strain (MIC, 1,600 microg/ml) was reduced by at least 15-fold and up to 500-fold. We now describe the sequencing of 21 Tn551-inactivated genes and their vicinities in 23 new auxiliary mutants that have been studied before. Using the inverted polymerase chain reaction (IPCR), we amplified fragments corresponding to the right and left junction of the Tn551 insertions, which were then sequenced by primer walking. The two largest groups of these new auxiliary genes encoded either proteins of unknown functions (6 genes) or showed homology with genes encoding proteins involved with putative sensory/regulatory activities (7 genes: protein kinases, ABC transporters, and a catabolite control protein). Sequencing upstream and downstream allowed the identification of a number of additional open reading frames, some of which may also include functions relevant for the expression of antibiotic resistance.

Liposomal lurtotecan (NX211): determination of total drug levels in human plasma and urine by reversed-phase high-performance liquid chromatography

Lurtotecan (GI147211; LRT) is a semisynthetic and water-soluble analogue of the topoisomerase I inhibitor camptothecin. To determine whether the therapeutic efficacy of LRT in patients could be improved, the drug was encapsulated in liposomes (NX211; Gilead Sciences). In order to allow accurate description of the pharmacokinetic behavior of NX211 in cancer patients, we have developed sensitive RP-HPLC assays with fluorescence detection (lambdaex=378 nm; lambdaem=420 nm) for the determination of total LRT levels in human plasma and urine. Sample pretreatment involved deproteinization with 10% (w/v) aqueous perchloric acid-acetonitrile (2:1, v/v), and chromatographic separations were achieved on an Inertsil-ODS 80A analytical column. The lower limit of quantitation (LLQ) was established at 1.00 ng/ml in plasma (200-microl sample) and at 100 ng/ml in urine (200 microl of 40-fold diluted sample). The within-run and between-run precisions were <7.5%. LRT concentrations in urine of <100 ng/ml were determined by a modified procedure comprising a single solvent extraction with n-butanol-diethyl ether (3:4, v/v). In this assay, the fluorescence signal of LRT was increased 14-fold prior to detection by post-column exposure to UV light (254 nm) in a photochemical reaction unit. The LLQ of this assay was 0.500 ng/ml (150-microl sample) and the within-run and between-run precisions were <10%.

Development and preliminary evaluation of an instrument designed to assess dental students' communication skills

The aim of this study was to develop, and assess the inter-observer reliability of an instrument for evaluating dental students' communication skills. Methods used were process-tracking of interactions between experienced practitioners and patients, development of the instrument and its simultaneous use by two researchers observing 43 third year dental students prior to communication skills training. The results found that the instrument was appropriate for the purpose for which it was designed, and was easy to utilise. There were no significant differences between observers' total scores. Item-specific weighted kappa scores showed almost perfect agreement between observers for all but four of the 31 items. The lowest interobserver weighted kappa score was for the measurement of eye contact (k = 0.60). In conclusion, assessment of communication skills is now a necessity in the undergraduate curriculum. Preliminary analysis of an instrument of communication skills in the dental surgery indicates that it may be possible to do this reliably.

Cloning, genomic organization and expression of a putative human transmembrane protein related to the Caenorhabditis elegans M01F1.4 gene

A novel human transcript CG-2 (C9ORF5), was isolated from the familial dysautonomia candidate region on 9q31 using a combination of cDNA selection and exon trapping. CG-2 was detected as a relatively abundant 8kb transcript in all adult and fetal tissues with the exception of adult thymus. Genomic analysis of CG-2 identified 18 exons that span more than 110kb. The gene encodes a 911-amino-acid protein with a predicted molecular weight of 101kDa and a hypothetical pI of 9.03. Sequence analysis of CG-2 indicates that it is likely to encode a transmembrane protein. Here, we assess CG-2 as a candidate for familial dysautonomia.

BCL10 is rarely mutated in human prostate carcinoma, small-cell lung cancer, head and neck tumours, renal carcinoma and sarcomas. MPT Collaborators, St George's Hospital Collaborators

We have used single-strand conformation polymorphism (SSCP) analysis to screen for mutations in the BCL10 gene in 81 primary prostate carcinomas, 20 squamous cell cancers of the head and neck, 15 small-cell lung cancer cell lines, 24 renal carcinoma cell lines and 13 sarcoma cell lines. We failed to find evidence of somatically acquired mutations of the BCL10 gene suggesting that BCL10 does not play a major role in the development of these malignancies.

Cloning, mapping, and expression of two novel actin genes, actin-like-7A (ACTL7A) and actin-like-7B (ACTL7B), from the familial dysautonomia candidate region on 9q31

Two novel human actin-like genes, ACTL7A and ACTL7B, were identified by cDNA selection and direct genomic sequencing from the familial dysautonomia candidate region on 9q31. ACTL7A encodes a 435-amino-acid protein (predicted molecular mass 48.6 kDa) and ACTL7B encodes a 415-amino-acid protein (predicted molecular mass 45. 2 kDa) that show greater than 65% amino acid identity to each other. Genomic analysis revealed ACTL7A and ACTL7B to be intronless genes contained on a common 8-kb HindIII fragment in a "head-to-head" orientation. The murine homologues were cloned and mapped by linkage analysis to mouse chromosome 4 in a region of gene order conserved with human chromosome 9q31. No recombinants were observed between the two genes, indicating a close physical proximity in mouse. ACTL7A is expressed in a wide variety of adult tissues, while the ACTL7B message was detected only in the testis and, to a lesser extent, in the prostate. No coding sequence mutations, genomic rearrangements, or differences in expression were detected for either gene in familial dysautonomia patients.

Precise genetic mapping and haplotype analysis of the familial dysautonomia gene on human chromosome 9q31

Familial dysautonomia (FD) is an autosomal recessive disorder characterized by developmental arrest in the sensory and autonomic nervous systems and by Ashkenazi Jewish ancestry. We previously had mapped the defective gene (DYS) to an 11-cM segment of chromosome 9q31-33, flanked by D9S53 and D9S105. By using 11 new polymorphic loci, we now have narrowed the location of DYS to <0.5 cM between the markers 43B1GAGT and 157A3. Two markers in this interval, 164D1 and D9S1677, show no recombination with the disease. Haplotype analysis confirmed this candidate region and revealed a major haplotype shared by 435 of 441 FD chromosomes, indicating a striking founder effect. Three other haplotypes, found on the remaining 6 FD chromosomes, might represent independent mutations. The frequency of the major FD haplotype in the Ashkenazim (5 in 324 control chromosomes) was consistent with the estimated DYS carrier frequency of 1 in 32, and none of the four haplotypes associated with FD was observed on 492 non-FD chromosomes from obligatory carriers. It is now possible to provide accurate genetic testing both for families with FD and for carriers, on the basis of close flanking markers and the capacity to identify >98% of FD chromosomes by their haplotype.

Telomerase repressor sequences on chromosome 3 and induction of permanent growth arrest in human breast cancer cells

BACKGROUND

Activation of the enzyme telomerase, which has been associated with cellular immortality, may constitute a key step in the development of human cancer. Telomerase is repressed in most normal human somatic cells. This study was conducted, using a genetic complementation approach, with the aim of identifying and mapping the genes responsible for repressing telomerase and, simultaneously, to establish the effect of experimentally induced telomerase repression on human tumor cell growth.

METHODS

Individual human chromosomes isolated from normal diploid cells and tagged with bacterial antibiotic resistance genes (for later selection) were introduced into cells of the human breast carcinoma cell line 21NT by means of microcell transfer. Selected hybrid clones were screened for telomerase activity by use of the polymerase chain reaction-based telomere repeat amplification protocol (TRAP) assay, and the proliferative fate of the hybrid clones was determined. Regions of the introduced chromosomes associated with telomerase repression were mapped using segregant hybrids and a deletion analysis that employed microsatellite DNA markers.

RESULTS

Strong repression of telomerase was observed following transfer of human chromosome 3 into 21NT cells but not after transfer of chromosomes 8, 12, or 20. The vast majority of hybrid clones with repressed telomerase entered permanent growth arrest after 10-18 population doublings. Deletion analysis of nonrepressed segregant monochromosome 3 hybrids indicated two regions on the short arm of chromosome 3 (3p21.3-p22 and 3p12-21.1) where telomerase regulator genes may be located.

CONCLUSIONS

Telomerase in human breast cancer cells is efficiently repressed by a gene or genes on normal human chromosome 3p, and this repression is associated with permanent growth arrest of the tumor cells.

Linkage analysis of chromosome 1q markers in 136 prostate cancer families. The Cancer Research Campaign/British Prostate Group U.K. Familial Prostate Cancer Study Collaborators

Prostate cancer shows evidence of familial aggregation, particularly at young ages at diagnosis, but the inherited basis of familial prostate cancer is poorly understood. Smith et al. recently found evidence of linkage to markers on 1q, at a locus designated "HPC1," in 91 families with multiple cases of early-onset prostate cancer. Using both parametric and nonparametric methods, we attempted to confirm this finding, in 60 affected related pairs and in 76 families with three or more cases of prostate cancer, but we found no significant evidence of linkage. The estimated proportion of linked families, under a standard autosomal dominant model, was 4%, with an upper 95% confidence limit of 31%. We conclude that the HPC1 locus is responsible for only a minority of familial prostate cancer cases and that it is likely to be most important in families with at least four cases of the disease.

The complete genome sequence of the hyperthermophilic, sulphate-reducing archaeon Archaeoglobus fulgidus

Archaeoglobus fulgidus is the first sulphur-metabolizing organism to have its genome sequence determined. Its genome of 2,178,400 base pairs contains 2,436 open reading frames (ORFs). The information processing systems and the biosynthetic pathways for essential components (nucleotides, amino acids and cofactors) have extensive correlation with their counterparts in the archaeon Methanococcus jannaschii. The genomes of these two Archaea indicate dramatic differences in the way these organisms sense their environment, perform regulatory and transport functions, and gain energy. In contrast to M. jannaschii, A. fulgidus has fewer restriction-modification systems, and none of its genes appears to contain inteins. A quarter (651 ORFs) of the A. fulgidus genome encodes functionally uncharacterized yet conserved proteins, two-thirds of which are shared with M. jannaschii (428 ORFs). Another quarter of the genome encodes new proteins indicating substantial archaeal gene diversity.

Fusion of splicing factor genes PSF and NonO (p54nrb) to the TFE3 gene in papillary renal cell carcinoma

We demonstrate that the cytogenetically defined translocation t(X;1)(p11.2;p34) observed in papillary renal cell carcinomas results in the fusion of the splicing factor gene PSF located at 1p34 to the TFE3 helix-loop-helix transcription factor gene at Xp11.2. In addition we define an X chromosome inversion inv(X)(p11.2;q12) that results in the fusion of the NonO (p54nrb) gene to TFE3. NonO (p54nrb), the human homologue of the Drosophila gene NonAdiss which controls the male courtship song, is closely related to PSF and also believed to be involved in RNA splicing. In each case the rearrangement results in the fusion of almost the entire splicing factor protein to the TFE3 DNA-binding domain. These observations suggest the possibility of intriguing links between the processes of RNA splicing, DNA transcription and oncogenesis.

Ticlopidine-associated pancytopenia: implications of an acetylsalicylic acid alternative

Ticlopidine is an antiplatelet agent that has been proven efficacious in preventing vascular events in patients with a history of vasculopathy. Neutropenia is a significant adverse effect and pancytopenia is rarely reported. A fatal case of pancytopenia associated with unmonitored use of ticlopidine is presented. A 59-year-old woman presented with severe pneumonia and profound neutropenia (absolute neutrophil count 0%). She deteriorated with development of acute respiratory distress syndrome and a marked reduction in trilineage hematopoiesis. Despite prompt marrow response to granulocyte macrophage colony-stimulating factor (GM-CSF) and cessation of ticlopidine, appropriate antibiotics and other supportive therapy, she died 17 days after admission. Hematological monitoring is imperative to identify potential complications: if discovered late, there may be a role for GM-CSF for marrow support. Ticlopidine is indicated for patients intolerant of or nonresponsive to acetylsalicylic acid therapy. As the use of ticlopidine increases, clinicians must be aware of potential life-threatening complications associated with its use and monitor appropriately.

The complete genome sequence of the gastric pathogen Helicobacter pylori

Helicobacter pylori, strain 26695, has a circular genome of 1,667,867 base pairs and 1,590 predicted coding sequences. Sequence analysis indicates that H. pylori has well-developed systems for motility, for scavenging iron, and for DNA restriction and modification. Many putative adhesins, lipoproteins and other outer membrane proteins were identified, underscoring the potential complexity of host-pathogen interaction. Based on the large number of sequence-related genes encoding outer membrane proteins and the presence of homopolymeric tracts and dinucleotide repeats in coding sequences, H. pylori, like several other mucosal pathogens, probably uses recombination and slipped-strand mispairing within repeats as mechanisms for antigenic variation and adaptive evolution. Consistent with its restricted niche, H. pylori has a few regulatory networks, and a limited metabolic repertoire and biosynthetic capacity. Its survival in acid conditions depends, in part, on its ability to establish a positive inside-membrane potential in low pH.