The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Role of the mitogen-activated protein kinase Hog1p in morphogenesis and virulence of Candida albicans

The relevance of the mitogen-activated protein (MAP) kinase Hog1p in Candida albicans was addressed through the characterization of C. albicans strains without a functional HOG1 gene. Analysis of the phenotype of hog1 mutants under osmostressing conditions revealed that this mutant displays a set of morphological alterations as the result of a failure to complete the final stages of cytokinesis, with parallel defects in the budding pattern. Even under permissive conditions, hog1 mutants displayed a different susceptibility to some compounds such as nikkomycin Z or Congo red, which interfere with cell wall functionality. In addition, the hog1 mutant displayed a colony morphology different from that of the wild-type strain on some media which promote morphological transitions in C. albicans. We show that C. albicans hog1 mutants are derepressed in the serum-induced hyphal formation and, consistently with this behavior, that HOG1 overexpression in Saccharomyces cerevisiae represses the pseudodimorphic transition. Most interestingly, deletion of HOG1 resulted in a drastic increase in the mean survival time of systemically infected mice, supporting a role for this MAP kinase pathway in virulence of pathogenic fungi. This finding has potential implications in antifungal therapy.

A novel GSK-3beta inhibitor reduces Alzheimer's pathology and rescues neuronal loss in vivo

Amyloid deposits, neurofibrillary tangles, and neuronal cell death in selectively vulnerable brain regions are the chief hallmarks in Alzheimer's (AD) brains. Glycogen synthase kinase-3 (GSK-3) is one of the key kinases required for AD-type abnormal hyperphosphorylation of tau, which is believed to be a critical event in neurofibrillary tangle formation. GSK-3 has also been recently implicated in amyloid precursor protein (APP) processing/Abeta production, apoptotic cell death, and learning and memory. Thus, GSK-3 inhibition represents a very attractive drug target in AD and other neurodegenerative disorders. To investigate whether GSK-3 inhibition can reduce amyloid and tau pathologies, neuronal cell death and memory deficits in vivo, double transgenic mice coexpressing human mutant APP and tau were treated with a novel non-ATP competitive GSK-3beta inhibitor, NP12. Treatment with this thiadiazolidinone compound resulted in lower levels of tau phosphorylation, decreased amyloid deposition and plaque-associated astrocytic proliferation, protection of neurons in the entorhinal cortex and CA1 hippocampal subfield against cell death, and prevention of memory deficits in this transgenic mouse model. These results show that this novel GSK-3 inhibitor has a dual impact on amyloid and tau alterations and, perhaps even more important, on neuronal survival in vivo further suggesting that GSK-3 is a relevant therapeutic target in AD.

Molecular basis of cell integrity and morphogenesis in Saccharomyces cerevisiae

In fungi and many other organisms, a thick outer cell wall is responsible for determining the shape of the cell and for maintaining its integrity. The budding yeast Saccharomyces cerevisiae has been a useful model organism for the study of cell wall synthesis, and over the past few decades, many aspects of the composition, structure, and enzymology of the cell wall have been elucidated. The cell wall of budding yeasts is a complex and dynamic structure; its arrangement alters as the cell grows, and its composition changes in response to different environmental conditions and at different times during the yeast life cycle. In the past few years, we have witnessed a profilic genetic and molecular characterization of some key aspects of cell wall polymer synthesis and hydrolysis in the budding yeast. Furthermore, this organism has been the target of numerous recent studies on the topic of morphogenesis, which have had an enormous impact on our understanding of the intracellular events that participate in directed cell wall synthesis. A number of components that direct polarized secretion, including those involved in assembly and organization of the actin cytoskeleton, secretory pathways, and a series of novel signal transduction systems and regulatory components have been identified. Analysis of these different components has suggested pathways by which polarized secretion is directed and controlled. Our aim is to offer an overall view of the current understanding of cell wall dynamics and of the complex network that controls polarized growth at particular stages of the budding yeast cell cycle and life cycle.

Efficacy of aminocaproic, tranexamic acids in the control of bleeding during total knee replacement: a randomized clinical trial

BACKGROUND

Risks and costs of allogeneic blood transfusions mandate strategies to reduce blood loss in surgery. The objective of this study was to assess the efficacy of antifibrinolytic treatment in reducing perioperative blood loss during total knee replacement.

METHODS

A double-blind, randomized and placebo-controlled clinical trial was carried out on 127 patients undergoing total knee replacement. Patients in the study group received tranexamic acid 10 mg kg(-1) i.v. just before the tourniquet was deflated and 3 h later, or epsilon-aminocaproic acid 100 mg kg(-1) before tourniquet deflation followed by continuous perfusion (1 g h(-1)) during 3 h. External perioperative blood loss was measured and total blood loss was calculated. The number of patients transfused and number of packed red cell (PRC) units transfused was recorded and possible postoperative thromboembolic complications were investigated.

RESULTS

Total blood loss [mean (sd)] was 1099 ml (535) in the group that received antifibrinolytic agents and 1784 ml (660) in the control group (P<0.001). Five patients (7.5%) in the study group and 23 (38.3%) in the control group (P<0.001) received blood transfusions; the first group received a mean of 0.10 PRC unit per patient and the second, 0.58 (P<0.001). Mean reduction in haemoglobin levels (g dl(-1)) between preoperative and fifth day postoperative readings was 2.5 (0.9) in the study group and 3.4 (1.2) in the control group (P<0.001). Clinical assessment did not reveal any thromboembolic complications.

CONCLUSIONS

Antifibrinolytic agents produce a significant decrease in blood loss in patients undergoing total knee replacement, reflected in a reduction in the number of blood transfusions required.

Tissue production of pro-inflammatory cytokines (IL-1 , TNF and IL-6) correlates with the intensity of the systemic inflammatory response and with corticosteroid requirements in giant-cell arteritis

OBJECTIVES

To investigate proinflammatory cytokine expression in temporal arteries from patients with giant-cell arteritis (GCA) and to analyse its relationship with the intensity of the initial systemic inflammatory reaction and response to corticosteroid therapy.

METHODS

Quantification of interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNFalpha), and interleukin-6 (IL-6) mRNA by real-time quantitative PCR in temporal artery samples from 36 patients with biopsy-proven GCA and 11 controls. Immunohistochemical detection of IL-1beta, TNFalpha, and IL-6 in temporal artery sections from 74 patients with GCA and 15 controls. Clinical and biochemical parameters of inflammation as well as the time (weeks) required to reach a maintenance prednisone dose <10 mg/day were recorded.

RESULTS

IL-1beta (13.8 +/- 2.5 vs 5.4 +/- 1.3 relative units, P = 0.012) and IL-6 transcripts (34 +/- 13.7 vs 7.8 +/- 4.5 relative units, P = 0.034) were significantly more abundant in patients with a strong systemic inflammatory response compared with those with no inflammatory parameters. Immunohistochemical scores for IL-1beta (2.7 +/- 0.3 vs 1.9 +/- 0.2, P = 0.018), TNFalpha (3.2 +/- 0.2 vs 2.4 +/- 0.3, P = 0.028) and IL-6 (3 +/- 0.2 vs 2.1 +/- 0.3, P = 0.023) were also significantly higher in patients with strong systemic inflammatory reaction. A significant correlation was found between the amount of tissue TNFalpha mRNA and the time required to reach a maintenance dose of prednisone <10 mg/day (r = 0.586, P = 0.001).

CONCLUSION

GCA patients with a strong systemic inflammatory response, who have been previously shown to be more resistant to corticosteroid therapy, have elevated tissue expression of proinflammatory cytokines IL-1beta, TNFalpha and IL-6. High production of TNFalpha is associated with longer corticosteroid requirements.

Prevalence and clinical importance of sleep apnea in the first night after cerebral infarction

OBJECTIVE

To determine the prevalence of sleep apnea (SA) during the first night after hemispheric ischemic stroke and its influence on clinical presentation, course, and functional outcome at 6 months.

METHODS

The first night after cerebral infarction onset, 50 patients underwent polysomnography (PSG) followed by oximetry during the next 24 hours. Neurologic severity and early worsening were assessed by the Scandinavian Stroke Scale and outcome by the Barthel Index. Patients were evaluated on admission, on the third day, at discharge, and at 1, 3, and 6 months.

RESULTS

There were 30 males and 20 females with a mean age of 66.8 +/- 9.5 years. Latency between stroke onset and PSG was 11.6 +/- 5.3 hours. Thirty-one (62%) subjects had SA (apnea-hypopnea index [AHI] > or = 10). Of these, 23 (46%) had an AHI > or =20 and 21 (42%) an AHI > or =25. Sleep-related stroke onset occurred in 24 (48%) patients and was predicted only by an AHI > or =25 on logistic regression analysis. SA was related to early neurologic worsening and oxyhemoglobin desaturations but not to sleep history before stroke onset, infarct topography and size, neurologic severity, or functional outcome. Early neurologic worsening was found in 15 (30%) patients, and logistic regression analysis identified SA and serum glucose as its independent predictors.

CONCLUSIONS

SA is frequent during the first night after cerebral infarction (62%) and is associated with early neurologic worsening but not with functional outcome at 6 months. Cerebral infarction onset during sleep is associated with the presence of moderate to severe SA (AHI > or = 25).

Fibroblastic response to treatment with different preparations rich in growth factors

OBJECTIVES

Preparations rich in growth factors (PRGF) release them plus bioactive proteins at localized sites, with the aim of triggering healing and regenerative processes. The prevailing paradigm suggests that their influence on proliferation, angiogenesis and the extracellular matrix synthesis is minimal. However, variations in their composition and impact on different cell phenotypes have not been examined.

MATERIALS AND METHODS

Sixteen fibroblast cultures obtained from three different anatomical sites (skin, synovium and tendon) of 16 donors were exposed to the molecular pool released from PRGF scaffolds, with increasing amounts of platelets. We evaluated cell proliferation, secretion of angiogenic growth factors (VEGF and HGF), synthesis of type I collagen and hyaluronic acid (HA), considering platelet dose and anatomical origin of the cells. Activity of transforming growth factor-beta (TGF-beta) in type I procollagen and HA synthesis was examined by adding exogenous TGF-beta to plasma preparations.

RESULTS

All plasma preparations induced a significant proliferative response compared to non-stimulated cells (P < 0.05). Maximum proliferation rate was obtained with PRGF with 2-fold or 4-fold platelet concentration. Exposure to PRGF stimulated VEGF synthesis exclusively in tendon cells (P < 0.05), which also exhibited a different pattern of HGF production (P < 0.05). PRGF enhanced HA synthesis (P < 0.05), but did not alter collagen I production. Platelet-secreted TGF-beta may be involved in HA, but not in type I procollagen synthesis.

CONCLUSIONS

Optimizing composition and use of platelet-rich products is crucial to enhancing the therapeutic potential of this technology. Our data show that the biological effects of PRGF may depend on concentration of platelets and on the anatomical source of the cells.

Platelet-released growth factors enhance the secretion of hyaluronic acid and induce hepatocyte growth factor production by synovial fibroblasts from arthritic patients

OBJECTIVES

Autologous platelet-secreted growth factors (GFs) may have therapeutic effects in osteoarthritis (OA) capsular joints via multiple mechanisms. Our aim was to examine the effect of a platelet-derived preparation rich in growth factors (PRGFs) in OA synovial cell biology.

METHODS

Synovial cells were isolated from 10 osteoarthritic patients and cultured in serum-free media (basal conditions) and exposed to either a platelet-poor preparation or PRGF for 72 h. Cells activated with interleukin-1beta (IL-1beta) for 48 h were also exposed to PRGF. Changes in several events relevant to joint homeostasis including (i) hyaluronic acid (HA) secretion, (ii) the balance between metalloproteinase-1, -3 and -13 (MMP-1, MMP-3 and MMP-13) and tissue inhibitor-1 (TIMP-1) and (iii) the secretion of transforming growth factor-beta1(TGF-beta1), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), were all assessed.

RESULTS

PRGF significantly enhanced HA secretion compared with platelet-poor preparations, P < 0.05; at the same time release of TIMP-1, MMP-1, MMP-3 and MMP-13 were not affected. An increased HGF production was observed (P < 0.05) but VEGF and TGF-beta1 levels remained unchanged. PRGF significantly enhanced the secretion of HA induced by IL-1beta activation, P < 0.05, but it did not modify the IL-1beta-induced rise in MMP-1, MMP-3 and VEGF. In contrast, PRGF-induced HGF production was abolished by the presence of IL-1beta during PRGF treatment, P < 0.05.

CONCLUSIONS

Intra-articular administration of PRGF might be beneficial in restoring HA concentration and switching angiogenesis to a more balanced status but does not halt the effects of IL-1beta on synovial cells.

Decreased health care quality associated with emergency department overcrowding

The objective of this study was to assess the influence of overcrowding on health care quality provided by emergency departments (ED). The study was carried out in an urban, university tertiary care hospital. All patients seen at the internal medicine unit (IMU) of the ED who returned during the following 72 hours, and those who died in the ED rooms were included in the study. During a consecutive period of 2 years (104 weeks), we prospectively quantified the number of weekly visits, revisits and deaths. We calculated revisit and mortality rates (in respect of percentage of all visited patients) for each week. Correlation between the number of weekly visits, and revisit and mortality rates was assessed using a simple linear regression model. We consigned 81,301 visits, 1137 revisits and 648 deaths; mean (+/- SD) number of weekly visits, revisits and deaths were 782 (68), 10.93 (3.97) and 6.23 (3.04) respectively; weekly revisit rate was 1.40% (0.48%) and weekly mortality rate was 0.79% (0.36%). We observed a significant, positive correlation between mortality rates and weekly number of visits (p = 0.01). Although a similar trend was also found for revisit rates, such an increase did not reach statistical significance (p = 0.06). It is concluded that since revisit and mortality rates constitute good health care quality markers, present data demonstrate that ED overcrowding implies a decrease in the health care quality provided by it.

A protein kinase gene complements the lytic phenotype of Saccharomyces cerevisiae lyt2 mutants

By genetic analysis of a thermosensitive autolytic mutant whose phenotype was complemented by osmotic stabilization with sorbitol, we identified gene LYT2 of Saccharomyces cerevisiae, which is probably involved in cell wall formation. A yeast gene complementing lyt2 strains was cloned and shown to carry an open reading frame coding for a 484-amino-acid protein exhibiting all the characteristic domains of serine/threonine protein kinases and highly homologous to other yeast protein kinases involved in control of the mitotic cycle. Mutants disrupted in the cloned gene also displayed an autolytic phenotype complemented by osmotic stabilization with sorbitol. However, genetic comparison of lyt2 mutants and disruptants of the protein kinase gene revealed that the cloned gene is not the structural gene LYT2 but a suppressor of the lytic phenotype, named gene SLT2, that was mapped to chromosome V. The product of gene SLT2 is the first protein kinase to be described in relation to the yeast cell-wall functions.

Functional characterization of the MKC1 gene of Candida albicans, which encodes a mitogen-activated protein kinase homolog related to cell integrity

Mitogen-activated protein (MAP) kinases represent a group of serine/threonine protein kinases playing a central role in signal transduction processes in eukaryotic cells. Using a strategy based on the complementation of the thermosensitive autolytic phenotype of slt2 null mutants, we have isolated a Candida albicans homolog of Saccharomyces cerevisiae MAP kinase gene SLT2 (MPK1), which is involved in the recently outlined PKC1-controlled signalling pathway. The isolated gene, named MKC1 (MAP kinase from C. albicans), coded for a putative protein, Mkc1p, of 58,320 Da that displayed all the characteristic domains of MAP kinases and was 55% identical to S. cerevisiae Slt2p (Mpk1p). The MKC1 gene was deleted in a diploid Candida strain, and heterozygous and homozygous strains, in both Ura+ and Ura- backgrounds, were obtained to facilitate the analysis of the function of the gene. Deletion of the two alleles of the MKC1 gene gave rise to viable cells that grew at 28 and 37 degrees C but, nevertheless, displayed a variety of phenotypic traits under more stringent conditions. These included a low growth yield and a loss of viability in cultures grown at 42 degrees C, a high sensitivity to thermal shocks at 55 degrees C, an enhanced susceptibility to caffeine that was osmotically remediable, and the formation of a weak cell wall with a very low resistance to complex lytic enzyme preparations. The analysis of the functions downstream of the MKC1 gene should contribute to understanding of the connection of growth and morphogenesis in pathogenic fungi.

Mortality in Mexican patients with chronic pigeon breeder's lung compared with those with usual interstitial pneumonia

The clinical course of chronic pigeon breeder's lung (CPBL) is unknown, especially in comparison with usual interstitial pneumonia (UIP). We studied a cohort of 125 consecutive patients with interstitial lung diseases, including 78 patients with CPBL (74 biopsied) and 47 patients with UIP in the lung biopsy. Patients with UIP were divided into 17 without bird exposure (UIP) and 30 with bird exposure (UIP + BE). All patients were treated with corticosteroids and followed for 33 +/- 23 months. The best predictors of mortality (Cox proportional hazards model) were age > 44 yr, with a relative risk (RR) of 2.5 and 95% confidence interval (CI) of 1.4 to 4.7, masculine gender (RR 4.0, CI 2.1 to 7.6), x-ray honeycombing (RR 7.0, CI 3.8 to 12.7), and severity of fibrosis in the lung biopsy (RR 4.8, CI 2.3 to 9.7). Survival in CPBL 5 yr after diagnosis was 0.71 (SEM 0.08) and in UIP was 0.23 (SEM 0.08), with no statistical difference between UIP + BE and UIP. After adjusting for severity of fibrosis and honeycombing, however, the correlation of diagnosis with survival disappeared. In conclusion, mortality in CPBL is considerable, but lower than in UIP. Lung fibrosis and honeycombing seem to be a final common pathway for the ILD. Adjusting for them, the effect of diagnosis in survival is not significant.

Activation of glycogen synthase kinase-3 beta mediates β-amyloid induced neuritic damage in Alzheimer's disease

β-Amyloid (Aβ) plaques in Alzheimer (AD) brains are surrounded by severe dendritic and axonal changes, including local spine loss, axonal swellings and distorted neurite trajectories. Whether and how plaques induce these neuropil abnormalities remains unknown. We tested the hypothesis that oligomeric assemblies of Aβ, seen in the periphery of plaques, mediate the neurodegenerative phenotype of AD by triggering activation of the enzyme GSK-3β, which in turn appears to inhibit a transcriptional program mediated by CREB. We detect increased activity of GSK-3β after exposure to oligomeric Aβ in neurons in culture, in the brain of double transgenic APP/tau mice and in AD brains. Activation of GSK-3β, even in the absence of Aβ, is sufficient to produce a phenocopy of Aβ-induced dendritic spine loss in neurons in culture, while pharmacological inhibition of GSK-3β prevents spine loss and increases expression of CREB-target genes like BDNF. Of note, in transgenic mice GSK-3β inhibition ameliorated plaque-related neuritic changes and increased CREB-mediated gene expression. Moreover, GSK-3β inhibition robustly decreased the oligomeric Aβ load in the mouse brain. All these findings support the idea that GSK3β is aberrantly activated by the presence of Aβ, and contributes, at least in part, to the neuronal anatomical derangement associated with Aβ plaques in AD brains and to Aβ pathology itself.

[The relationship between palmitoyl-coenzyme A synthetase activity and esterification of sn-glycerol 3-phosphate in rat liver mitochondria]

1. The specific activities for palmitoyl-CoA synthetase and for sn-glycerol 3-phosphate esterification, with palmitoyl-CoA generated either by the endogenous synthetase or from palmitoyl-(-)-carnitine, CoA and excess of carnitine palmitoyltransferase, were measured with rat liver mitochondria. 2. The mean specific activity of palmitoyl-CoA synthetase was approximately five- and seven-fold the rates of sn-glycerol 3-phosphate esterification from palmitate and palmitoyl-(-)-carnitine respectively. No significant correlation was found in different rats between the activities of palmitoyl-CoA synthetase and sn-glycerol 3-phosphate esterification from either acyl precursor. However, there was a significant correlation (r=0.83, P<0.001) between the rates of glycerolipid synthesis from palmitate and palmitoyl-(-)-carnitine. 3. The mean molar composition of the glycerolipid synthesized from palmitate was 58% lysophosphatidate, 31% phosphatidate and 11% neutral lipid. With palmitoyl-(-)-carnitine the equivalent values were 70, 23 and 7%, which were significantly different. 4. When palmitoyl-CoA synthetase had been inactivated by 60-70% after preincubation of mitochondria at 37 degrees C, it became rate-limiting in glycerolipid biosynthesis. Additions of 1-5mm-ATP prevented inactivation of palmitoyl-CoA synthetase. 5. Preincubation also inhibited the oxidation of palmitate, palmitoyl-CoA, palmitoyl-(-)-carnitine and malate plus glutamate. These inhibitions could not be prevented by addition of ATP. 6. Diversion of palmitoyl-CoA to form palmitoyl-(-)-carnitine did not inhibit sn-glycerol 3-phosphate esterification. 7. The palmitoyl-CoA pool synthesized by the palmitoyl-CoA synthetase was augmented by adding partially purified synthetase or carnitine palmitoyltransferase and palmitoyl-(-)-carnitine. No stimulation of palmitate incorporation into glycerolipids occurred. 8. At low concentrations of Mg(2+), palmitate, ATP and CoA the velocity with palmitoyl-CoA synthetase decreased more than that of glycerolipid synthesis from palmitate. 9. It is concluded that in the presence of optimum substrate concentrations the activity of sn-glycerol 3-phosphate acyltransferase and not of palmitoyl-CoA synthetase is rate-limiting in the synthesis of phosphatidate and lysophosphatidate in isolated rat liver mitochondria.

Virulence genes in the pathogenic yeast Candida albicans

In recent years, the incidence of fungal infections has been rising all over the world. Although the amount of research in the field of pathogenic fungi has also increased, there is still a need for the identification of reliable determinants of virulence. In this review, we focus on identified Candida albicans genes whose deletant strains have been tested in experimental virulence assays. We discuss the putative relationship of these genes to virulence and also outline the use of new different systems to examine the precise effect in virulence of different genes.

Validation of the tracer-balance concept with reference to leucine: 24-h intravenous tracer studies with L-[1-13C]leucine and [15N-15N]urea

The validity of tracer-derived estimates of whole-body leucine balance was investigated. Seven healthy young adult subjects received an adequate protein diet for 6 d; at 1800 on the last day, L-[1-13C]leucine and [15N-15N]urea were given as primed, continuous intravenous infusions for 24 h. Subjects were in a fasting state for the first 12 h and at 0600 on day 7 they then received hourly 10 equal meals to achieve a fed state. Total leucine intake (diet plus tracer) was 89.4 mg.kg-1.d-1. Mean daily leucine oxidation was equivalent to 89.5 +/- 3.3 mg leucine/kg. The predicted daily oxidation rate, from measurements made during the last hour of the fast and the fifth hour of the fed period, was 91.2 +/- 5.8 mg/kg (P = 0.25 from measured). Measured and predicted whole-body leucine balances were 0.76 +/- 2.99 and -0.98 +/- 5.54 mg/kg, respectively (P = 0.25). Urea production exceeded urea excretion by 20%; daily protein oxidation was the same when estimated from leucine oxidation or nitrogen excretion. Thus, the tracer-balance concept is valid, and reliable predictions of total daily leucine oxidation and whole-body leucine balance can be obtained from short-term measurements of leucine oxidation during fasted and fed states.

An SCL 3′ enhancer targets developing endothelium together with embryonic and adult haematopoietic progenitors

The SCL gene encodes a basic helix-loop-helix transcription factor which is expressed in early haematopoietic progenitors throughout ontogeny and is essential for the normal development of blood and blood vessels. Transgenic studies have characterised spatially distinct 5′ enhancers which direct lacZ expression to subdomains of the normal SCL expression pattern, but the same elements failed to produce appropriate haematopoietic expression. We now describe an SCL 3′ enhancer with unique properties. It directed lacZ expression in transgenic mice to extra-embryonic mesoderm and subsequently to both endothelial cells and to a subset of blood cells at multiple sites of embryonic haematopoiesis including the yolk sac, para-aortic splanchnopleura and AGM region. The 3′ enhancer also targeted expression to haematopoietic progenitors in both foetal liver and adult bone marrow. Purified lacZ(+)cells were highly enriched for clonogenic myeloid and erythroid progenitors as well as day-12 spleen colony forming units (CFU-S). Within the total gated population from bone marrow, 95% of the myeloid and 90% of the erythroid colony-forming cells were contained in the lacZ(+) fraction, as were 98% of the CFU-S. Activation of the enhancer did not require SCL protein. On the contrary, transgene expression in yolk sacs was markedly increased in an SCL−/− background, suggesting that SCL is subject to negative autoregulation. Alternatively the SCL−/− environment may alter differentiation of extra-embryonic mesoderm and result in an increased number of cells capable of expressing high levels of the transgene. Our data represents the first description of an enhancer that integrates information necessary for expression in developing endothelium and early haematopoietic progenitors at distinct times and sites throughout ontogeny. This enhancer provides a potent tool for the manipulation of haematopoiesis and vasculogenesis in vivo.

Activity of the yeast MAP kinase homologue Slt2 is critically required for cell integrity at 37 degrees C

Deletion of the SLT2 gene of Saccharomyces cerevisiae, which codes for a homologue of MAP (mitogen-activated) protein kinases, causes an autolytic lethal phenotype in cells grown at 37 degrees C. The gene encodes domains characteristic of protein kinases, which include a lysine (at position 54) that lies 19 residues from a glycine-rich cluster, considered to be the putative ATP binding site. The ability of three mutant alleles of SLT2 generated by site-directed mutagenesis, namely E54 (glutamic acid), R54 (arginine) and F54 (phenylalanine), to complement slt2 mutants was tested. All three failed to complement the autolytic phenotype and were unable to restore growth and viability of cells. A strain obtained by transplacement of slt2-F54 also behaved as a thermosensitive autolytic mutant. By immunoprecipitation with polyclonal antibodies raised against Slt2 protein expressed in Escherichia coli, it was possible to confirm that alteration of the lysine-54 residue did not affect the stability of the protein, thus allowing us to conclude that activity of the Slt2 protein kinase is critically required for growth and morphogenesis of S. cerevisiae at 37 degrees C. A significant fraction of the mutant cell population lysed at 24 degrees C and the cells displayed a characteristic alteration of the surface consisting of a typical depression in an area of the cell wall. At 37 degrees C, the cell surface was clearly disorganized.

A major secreted elastase is essential for pathogenicity of Aeromonas hydrophila

Aeromonas hydrophila is an opportunistic pathogen and the leading cause of fatal hemorrhagic septicemia in rainbow trout. A gene encoding an elastolytic activity, ahyB, was cloned from Aeromonas hydrophila AG2 into pUC18 and expressed in Escherichia coli and in the nonproteolytic species Aeromonas salmonicida subsp. masoucida. Nucleotide sequence analysis of the ahyB gene revealed an open reading frame of 1,764 nucleotides with coding capacity for a 588-amino-acid protein with a molecular weight of 62,728. The first 13 N-terminal amino acids of the purified protease completely match those deduced from DNA sequence starting at AAG (Lys-184). This finding indicated that AhyB is synthesized as a preproprotein with a 19-amino-acid signal peptide, a 164-amino-acid N-terminal propeptide, and a 405-amino-acid intermediate which is further processed into a mature protease and a C-terminal propeptide. The protease hydrolyzed casein and elastin and showed a high sequence similarity to other metalloproteases, especially with the mature form of the Pseudomonas aeruginosa elastase (52% identity), Helicobacter pylori zinc metalloprotease (61% identity), or proteases from several species of Vibrio (52 to 53% identity). The gene ahyB was insertionally inactivated, and the construct was used to create an isogenic ahyB mutant of A. hydrophila. These first reports of a defined mutation in an extracellular protease of A. hydrophila demonstrate an important role in pathogenesis.

Correlation between the structure and biochemical activities of FtsA, an essential cell division protein of the actin family

Cell division protein FtsA, predicted to belong to the actin family, is present in different cell compartments depending on its phosphorylation state. The FtsA fraction isolated from the cytoplasm is phosphorylated and capable of binding ATP, while the membrane-bound form is unphosphorylated and does not bind ATP. A variant of the protein FtsA102, in which the nucleotide binding site was destroyed by mutagenesis of a highly conserved residue predicted to be needed for the binding, does not bind ATP. Another variant, FtsA104, cannot be phosphorylated because the predicted phosphorylatable residue has been replaced by a non-phosphorylatable one. This protein although unable to bind ATP in vitro, is able to rescue the reversible ftsA2, the irreversible ftsA3 and, almost with the same efficiency, the ftsA16 amber alleles. Consequently, phosphorylation and ATP binding may not be essential for the function of FtsA. Alternatively they may have a regulatory role on the action of FtsA in the septator.

Analysis of patient flow in the emergency department and the effect of an extensive reorganisation

OBJECTIVES

To evaluate the different internal factors influencing patient flow, effectiveness, and overcrowding in the emergency department (ED), as well as the effects of ED reorganisation on these indicators.

METHODS

The study compared measurements at regular intervals of three hours of patient arrivals and patient flow between two comparable periods (from 10 February to 2 March) of 1999 and 2000. In between, a structural and staff reorganisation of ED was undertaken. The main reason for each patient remaining in ED was recorded and allocated to one of four groups: (1) factors related to ED itself; (2) factors related to ED-hospital interrelation; (3) factors related to hospital itself; and (4) factors related to neither ED nor hospital. The study measured the number of patients waiting to be seen and the waiting time to be seen as effectiveness markers, as well as the percentage of time that ED was overcrowded, as judged by numerical and functional criteria.

RESULTS

Effectiveness of ED was closely related with some ED related and hospital related factors. After the reorganisation, patients who remained in ED because of hospital related or non-ED-non-hospital related factors decreased. ED reorganisation reduced the number of patients waiting to be seen from 5.8 to 2.5 (p<0.001) and waiting time from 87 to 24 minutes (p<0.001). Before the reorganisation, 31% and 48% of the time was considered to be overcrowded in numerical and functional terms respectively. After the reorganisation, these figures were reduced to 8% and 15% respectively (p<0.001 for both).

CONCLUSIONS

ED effectiveness and overcrowding are not only determined by external pressure, but also by internal factors. Measurement of patient flow across ED has proved useful in detecting these factors and in being used to plan an ED reorganisation.

Is microbubble-enhanced ultrasonography sufficient for assessment of response to percutaneous treatment in patients with early hepatocellular carcinoma?

The objective of this study was to assess the efficacy of contrast-enhanced ultrasonography (CEUS) with SonoVue to evaluate the response to percutaneous treatment (ethanol injection/radiofrequency) of hepatocellular carcinoma in comparison with spiral computed tomography (CT) immediately and 1 month after treatment. Forty-one consecutive cirrhotic patients with early stage tumor (not suitable for resection) were included. Spiral CT and CEUS were performed in all patients before treatment, in the following 24 h, and 1 month later. The results of each examination were compared with the 1-month spiral CT, considered the gold standard technique. The 24-h CEUS and the 24-h spiral CT sensitivity to detect residual disease were 27% and 20%, respectively. The 24-h CEUS and the 24-h spiral CT positive predictive value of persistent vascularization detection were 75% and 66%, respectively. The 1-month CEUS detected partial responses in ten out of 11 cases (91% sensitivity, 97% specificity, 95% accuracy). Spiral CT and CEUS performed in the 24 h following treatment are slightly useful to evaluate therapeutic efficacy. The 1-month CEUS has a high diagnostic accuracy compared with spiral-CT in the usual assessment of percutaneous treatment response.

Long-term prognosis of hypertension in pregnancy

OBJECTIVES

To assess the prevalence of subsequent hypertension in women with hypertensive pregnancies and evaluate it according to the subclassifications of hypertension in pregnancy.

METHODS

A survey was carried out in 476 women with hypertensive pregnancies (cases) and 226 normotensive controls delivered between 1973 and 1991 in a tertiary-level teaching hospital. They were invited to participate by mail and 273 cases (57%) and 86 controls (38%) completed the analysis. Outcomes assessed were prevalences of hypertension, diabetes, and hypercholesterolemia, together with cardiovascular morbidity.

RESULTS

Among responders, age and parity were similar in both groups although follow-up time was longer in controls. Subsequent hypertension was more frequent within cases. After excluding chronic and unclassifiable hypertension, the mean blood pressure was higher in all other forms of pregnancy hypertension (103 +/- 13 mm Hg versus 94 +/- 13 mm Hg, p < 0.001); long-term hypertension prevalence was 45% in cases and 14% in controls [odds ratio (OR) = 5.1; 95% confidence interval (95% CI) = 2.5-9.8; p < 0. 001]. There were no differences with respect to the prevalences of subsequent diabetes or hypercholesterolemia. Remote hypertension was more common following gestational hypertension (54%) than in preeclampsia (38%), eclampsia (14%), or normotensive cases (14%) (OR for gestational hypertension versus normotensives = 7.2; 95% CI = 3. 4-14.8, p < 0.001, and OR for preeclampsia versus normotensives = 3. 7; 95% CI = 1.7-7.9, p < 0.001).

CONCLUSIONS

After an average of 13. 6 years since the index pregnancy, women with hypertensive pregnancies have an increased risk of subsequent hypertension. Gestational hypertension is the hypertensive disorder of pregnancy with the highest incidence of subsequent hypertension. Women with preeclampsia have a greater tendency to develop hypertension than women with normotensive pregnancies. By contrast, women with eclampsia do not.

Multicenter study evaluating a dual policy of postorchiectomy surveillance and selective adjuvant single-agent carboplatin for patients with clinical stage I seminoma

BACKGROUND

After decades of irradiation as standard therapy for clinical stage I testicular seminoma, alternative treatment approaches have emerged including postorchiectomy surveillance and adjuvant chemotherapy. This study was performed to assess a dual policy of surveillance and selective single-agent carboplatin (for high-risk cases) in a multicenter setting.

PATIENTS AND METHODS

From 1994 to 1999, 203 patients with stage I seminoma were included. Sixty (29.6%) were considered poor-risk cases (i.e. with vascular invasion and/or pathological tumor stage pT2 or greater) and received two courses of adjuvant carboplatin, whereas 143 (70.4%) without risk criteria underwent close surveillance.

RESULTS

Median follow-up was 52 months (range 14-92). Relapses were observed in two (3.3%) patients treated with carboplatin and in 23 patients (16.1%) on surveillance, with a median time to recurrence of 11 months (range 3.9-39.6). All relapsing patients were rendered disease-free, mainly with cisplatin-based chemotherapy. Four patients died from tumor-unrelated causes. Actuarial 5-year overall survival was 96.7% and cause-specific survival was 100%. Five-year disease-free survival was 83.5% for patients on surveillance, and 96.6% for those receiving carboplatin.

CONCLUSIONS

This dual treatment policy is feasible in a multicenter setting and preserves 70% of patients from adjuvant chemotherapy. Single-agent carboplatin is effective in reducing the relapse rate in patients with high-risk stage I seminoma. A better definition of local risk features would probably improve patient selection, thus minimizing the incidence of recurrences on surveillance.