A Randomized Controlled Trial of R-Form Verapamil Added to Ongoing Metformin Therapy in Patients with Type 2 Diabetes

CONTEXT

There is a medical need for effective insulin-independent antidiabetic drugs that can promote pancreatic β-cell function and have a low risk of hypoglycemia in type 2 diabetes mellitus (T2DM) patients. R-form verapamil (R-Vera), which is able to enhance the survival of β-cells and has higher cardiovascular safety margin compared with racemic verapamil, was developed as a novel approach for T2DM treatment.

OBJECTIVE

This randomized, double-blind, placebo-controlled clinical trial was designed to evaluate the efficacy and safety of 3 dosages of R-Vera added to ongoing metformin therapy in T2DM patients who had inadequate glycemic control on metformin alone.

METHODS

Participants were randomly assigned in an equal ratio to receive R-Vera 450, 300, or 150 mg per day, or matching placebo, in combination with metformin. The primary endpoint was change in hemoglobin A1c (HbA1c) after 12 weeks of treatment.

RESULTS

A total of 184 eligible participants were randomized to receive either R-Vera or placebo plus metformin. At week 12, significant reductions in HbA1c were observed for R-Vera 300 mg/day (-0.36, P = 0.0373) and 450 mg/day (-0.45, P = 0.0098) compared with placebo. The reduction in HbA1c correlated with decreasing fasting plasma glucose levels and improved HOMA2-β score. Treatment with R-Vera was well tolerated with no hypoglycemic episodes occurring during the trial.

CONCLUSION

Addition of R-Vera twice daily to ongoing metformin therapy significantly improved glycemic control in T2DM patients. The favorable efficacy and safety profile of R-Vera 300 mg/day can be considered as the appropriate dose for clinical practice.

Structure-dependent behaviours of skin layers studied by atomic force microscopy

The multilayer skin provides the physical resistance and strength against the environmental attacks, and consequently plays a significant role in maintaining the mammalian health. Currently, optical microscopy (OM) is the most common method for the research related to skin tissues while with the drawbacks including the possibility of changing the native morphology of the sample with the addition of the chemical or immunological staining and the restricted resolution of images for the direct observation of the tissue structures. To investigate if the function of each tissue is structure-dependent and the how the injured skin returns to the intact condition, we applied atomic force microscopy (AFM) on the sectioned mice-skin to reveal the tissue structures with a nanoscale resolution. From the outermost stratum to the inner layer of the skin tissue, the respectively laminated, fibrous, and brick-like structures were observed and corresponded to various functions. Due to the mechanical differences between the tissue constituents and their boundaries, the sizes and arrangements of the components were characterised and quantified by the mechanical mapping of AFM, which enabled the analytical comparisons between tissue layers. For the wound model, the skin tissues were examined with the initial formation of blood vessels and type-I collagen, which agreed with the stage of healing process estimated by OM but showed more detail information about the evolution of proteins among the skin. In conclusion, the characterisation of the components that consist of skin tissue by AFM enables the connection of the tissue function to the corresponded ultrastructure.

Synthesis and Characterization of Modified Phenylethynyl Imides

As an ongoing effort to develop structural adhesives for high-performance aerospace applications, recent work has focused on phenylethynyl terminated imide (PETI) oligomers. The work reported herein involves the synthesis and characterization of a series of phenylethynyl containing oligomers designated LARC™ MPEI (modified phenylethynyl imide). These oligomers presumably contain mixtures of linear, branched and star-shaped molecules. The fully imidized polymers exhibited minimum melt viscosities as low as 600 poise at 335 °C, significantly lower than equivalent molecular weight linear materials. Ti/Ti lap shear specimens processed at 288 °C under 15 psi showed tensile shear strengths as high as ∼6000 psi and ∼5200 psi at ambient temperature and 177 °C respectively. The chemistry and properties of these new MPEIs are presented and compared with an optimized linear PETI, LARC™ PETI-5.

A nontransfusional perioperative management regimen for patients with sickle cell disease undergoing laparoscopic cholecystectomy

BACKGROUND

Patients with sickle cell disease (SCD) are at increased risk for cholelithiasis. Laparoscopic cholecystectomy is the most frequent general surgical operation performed for this group of patients. Acute chest syndrome (ACS) is the most common cause of postoperative death among SCD patients. This study aimed to evaluate the impact of a novel perioperative management regimen involving prophylactic continuous positive airways pressure (CPAP) ventilation and avoidance of preoperative blood transfusion on postoperative SCD-related complications after laparoscopic cholecystectomy.

METHODS

A retrospective study included all SCD patients who underwent laparoscopic cholecystectomy since 1997 at our institution. Medical notes were analyzed to assess the rates of postoperative complications in relation to the severity of SCD.

RESULTS

A total of 13 patients were identified. There were no recorded episodes of acute painful crises and only one patient experienced an episode of ACS requiring protracted CPAP.

CONCLUSION

Laparoscopic cholecystectomy can be safely performed for SCD patients without prior blood transfusion. A defined perioperative regimen including the use of routine postoperative prophylactic CPAP for these patients helps to reduce SCD-related postoperative complications such as ACS and painful vaso-occlusive crises.

Mesenteric oxyhemoglobin desaturation improves with patent ductus arteriosus ligation

Near-infrared spectroscopy was used to monitor cerebral and mesenteric regional oximetry in a preterm neonate undergoing surgical ligation of a patent ductus arteriosus. This patient initially demonstrated severe mesenteric oxyhemoglobin desaturation, which improved immediately following ductal ligation.

Heavy metal sequential extraction methods--a modification for tropical soils

Sequential extractions of metals can be useful to study metal distributions in various soil fractions. Although several sequential extraction procedures have been suggested in the literature, most were developed for temperate soils and may not be suitable for tropical soils with high contents of Mn and Fe oxides. The objective of this study was to develop a sequential fractionation procedure for Cu and Zn in tropical soils. Extractions were performed on surface (0-20 cm) samples of ten representative soils of Sao Paulo State, Brazil. Chemically reactive Mn forms were satisfactorily assessed by the new modified procedure. Amorphous and crystalline Fe oxides were more selectively extracted in a new two-step extraction. Soil-born Zn and Cu were primarily associated with recalcitrant soil fractions. The proposed procedure provided more detailed information on metal distribution in tropical soils and better characterization of the various components of the soil matrix. The new procedure is expected to be an important tool for predicting the potential effects of environmental changes and land application of metals on the redistribution of chemical forms of metals in tropical soils.

A prospective evaluation of nesiritide in the treatment of pediatric heart failure

This study sought to determine the potential of recombinant B-type natriuretic peptide (nesiritide) for the treatment of pediatric decompensated heart failure. Nesiritide is a widely used and effective treatment for decompensated heart failure (HF) in adults, but its safety and efficacy in pediatric patients is unclear. Outcomes of 55 separate nesiritide infusions of varying durations in 32 patients (13 males and 19 females; mean age, 8.01 years; range, 0.01-20.4) were evaluated prospectively. All patients received nesiritide in the intensive care unit. The starting dose (0.01 microg/kg/min) was titrated to a maximum of 0.03 microg/kg/min. All patients were monitored for clinical signs and symptoms, hemodynamics, urine output, electrolytes, oxygen requirements, and oral intake. Functional status was assessed by patients and/or their parents. All patients successfully underwent initiation and titration of nesiritide infusion. No hypotension or arrhythmias were noted during 478 cumulative days of therapy. Nesiritide was given safely with vasoactive medications. Mean urine output improved from 2.35 +/- 1.71 cc/kg/hr on the day before nesiritide initiation (baseline) to 3.10 +/- 1.94 cc/kg/hr on day 4 of treatment (p < 0.01). Serum creatinine decreased from 1.04 to 0.92 mg/dl (p = 0.096), mean central venous pressure from 13 to 7 mmHg (p = 0.018), and mean weight from 30.4 to 29.7 kg (p < 0.001) with therapy. Thirst, as subjectively assessed by patients old enough to respond, decreased with infusion in 31 of 42 cases (74%). Mean New York Heart Association functional class improved significantly (p < 0.001). Nesiritide infusion, alone or in combination, is a safe treatment for decompensated HF in pediatric patients. It is associated with decreased thirst and improved urine output and functional status, and it may be efficacious in the treatment of pediatric HF.

Genomic amplification of MET with boundaries within fragile site FRA7G and upregulation of MET pathways in esophageal adenocarcinoma

Esophageal adenocarcinoma (EA) is characterized by a poor prognosis making the identification of clinically targetable proteins essential for improving patient outcome. We report the involvement of multiple alterations of the MET pathway in EA development and progression. Microarray analysis of Barrett's metaplasia, dysplasia, and EA revealed overexpression of the MET oncogene in EAs but only those with MET gene amplification. STS-amplification mapping revealed that the boundary of the MET amplicon in these EAs is defined by fragile site FRA7G. We also identified an amplicon at 11p13 that resulted in amplification and overexpression of CD44, a gene involved in MET autophosphorylation upon HGF stimulation. Tissue microarrays with phospho-MET-specific antibodies demonstrated a uniformly high abundance of MET activation in primary EA and cells metastatic to lymph nodes but to a lesser extent in a subset of metaplastic and dysplastic Barrett's samples. Increased expression of multiple genes in the MET pathway associated with invasive growth, for example, many MMPs and osteopontin, also was found in EAs. Treatment of EA-derived cell lines with geldanamycin, an inhibitor for tyrosine kinases including MET receptor kinase, reduced cell migration and induced EA cell apoptosis. The data indicate that upregulation of the MET pathway may contribute to the poor outcome of EA patients and that therapeutic agents targeting this pathway may help improve patient survival.

Neonate with vein of Galen malformation and heart failure: serial changes in plasma B-type natriuretic peptide following endovascular embolization

We report a neonate with vein of Galen malformation (VGM) who developed congestive heart failure (CHF) early after birth. Serial changes in plasma B-type natriuretic peptide (BNP) following an endovascular embolization procedure for VGM were mirrored in his clinical CHF status. The plasma BNP level markedly increased to 1800 pg/ml (normal, <100 pg/ml) in accordance with the severity of CHF. It rapidly decreased to 356 pg/ml during the first week after endovascular embolization for VGM. In the following 3 weeks there was an unexpected upward trend in plasma BNP despite echocardiography revealing normal biventricular function. After additional evaluation and treatment for CHF, BNP decreased again and the patient's clinical status concurrently improved. The patient was discharged with a normal BNP level. Monitoring serial plasma BNP provides valuable information regarding the need for additional evaluation or treatment of newborns with CHF and may be used to document improvement.

Captopril-induced pulmonary infiltrates with eosinophilia in an infant with congenital heart disease

We report a case of an infant with complex congenital heart disease who was placed on captopril for afterload reduction following cardiac surgery and subsequently developed pulmonary infiltrates with eosinophilia. The patient was readmitted with symptoms of rhinorrhea, poor feeding, and decreased activity level. She was found to have diffuse pulmonary infiltrates on chest radiograph and a marked peripheral eosinophilia without leukocytosis. After discontinuing captopril and starting systemic steroids, her symptomatology rapidly improved, and her eosinophilia and radiographic abnormalities both resolved.

Left ventricular noncompaction cardiomyopathy in association with trisomy 13

In recent years, left ventricular noncompaction (LVNC) has been recognized as a distinct form of cardiomyopathy with its own clinical presentation and natural history. More than 100 cases of LVNC have been described in children. Although LVNC has been described in association with metabolic disorders such as Fabry's disease or genetic disorders such as Roifman's syndrome, this case represents the first report of LVNC in a child with trisomy 13.

Mass balance modeling of arsenic processes in cropland soils

This study delineated the mathematical forms for the reactions involved in the mass balance of As in cropland soils. Even mathematically simplified, many model parameters are required to define the reactive processes involved. Example simulations were conducted based on the range of parameter values and initial conditions derived from published literature. The outcomes showed that the As inputs due to fertilizers and irrigation water caused total As content of the root zone to gradually increase over time. The plant uptake and leaching were equally important as pathways for removal of the added As. In turn, the dissolution kinetics of the mineral phase and the distribution coefficient of the adsorbed phase affected the availability of the As for plant uptake and leaching. Parameters based on laboratory-derived data on the dissolution of As mineral phase, mineralization and oxidation of As(III), and the As plant uptake however appeared to overestimate the As transformations in soils. While the development of mathematical model was a straightforward process, its application to realistic situations was hindered by difficulties of defining model parameter values with confidence. Current knowledge on the processes and reactions of As transformation in the soil-plant system is inadequate to calibrate or validate the model. Studies are needed to understand the kinetics of soil As mineral dissolution and precipitation and the dynamics of root growth and As uptake by plant in soils.

Altered dystrophin expression in the right atrium of a patient after Fontan procedure with atrial flutter

Underlying mechanisms in the development of atrial flutter or intra-atrial re-entry tachycardia in patients with structural cardiac abnormalities remain poorly defined. The right atrial myocardium from two patients with congenital heart disease was evaluated, of whom one presented with severe right atrial dilation and arrhythmia and the other with a normal right atrium, to assess whether increased right atrial pressure and volume overload give rise to sarcolemmal alteration. N-terminus dystrophin staining in the atrium from the patient who had undergone a Fontan procedure showed a normally distributed but significantly reduced staining signal compared with the second patient. This is the first report that patients with severe right atrial dilation and atrial flutter have marked reduction in atrial dystrophin expression.

Vasodilatory shock after surgery for aortic valve endocarditis: use of low-dose vasopressin

This is the case report of a 13-year-old male who developed vasopressor-resistant hypotension after cardiac surgery for endocarditis. As norepinephrine resulted in aggravation of the preexisting ventricular arrhythmia, vasopressin was used to maintain blood pressure. The vasopressin continuous infusion was started at 0.00002 units/kg/min and titrated up to 0.0003 U/kg/min. This low dose led to resolution of hypotension without causing side effects. As the appropriate indication and dose of vasopressin is not established, the cautious use of vasopressin in children is recommended.

Restricted expression of LUZP in neural lineage cells: a study in embryonic stem cells

A novel protein LUZP with 3 leucine zipper motifs at its amino terminus is predominantly expressed in the adult brain. A modified gene targeting approach was employed in an attempt to establish in vitro and in vivo models in which Luzp is knock-out (KO) for phenotype assessment and a reporter gene lacZ is knock-in (KI) for tracing its expression. We report in this study the molecular cloning of the Luzp gene, its targeting vector construction and Luzp-KO/lacZ-KI embryonic stem (ES) clone selection. Since LUZP is also expressed in ES cells, the possibility of embryonic lethality cannot be excluded when attempting to establish Luzp-null mutant mice. We have therefore examined the development of homozygous Luzp-KO/lacZ-KI clones in nude mice. Tissue types derived from all three embryonic germ layers were observed in teratomas developed in nude mice. In situ X-gal staining further revealed restricted expression of LUZP in neural lineage cells.

Seroprevalence and demographic characteristics of HTLV-I among blood donors in Taiwan: 1996-1999

Screening for the human T-cell lymphotropic virus type I (HTLV-I) and-II in blood donors was implemented in Taiwan beginning in February 1996. The purpose of the present study was to investigate the changes in HTLV-I seroprevalence in all unpaid blood donors in Taiwan during the period from February 1996 to December 1999 and to determine the influence of age and sex on the HTLV-I seropositivity of donors. HTLV-I and HTLV-II screening was performed using combined HTLV-I/II immunoassay. Repeated reactive samples were confirmed by Western blot analysis. Of a total of 3,701,087 donors in all 6 blood centers in Taiwan, 2,311 (0.058%) were seropositive for HTLV-I. The HTLV-I seropositivity was 0.130%, 0.063%, 0.044%, and 0.032% in the years 1996, 1997,1998, and 1999, respectively. There was a linear increase of HTLV-I seropositivity with advancing age. The HTLV-I carrier rate for female donors was twice that for the male donors. Ninty-seven percent of HTLV-I seropositive results came from first-time donors. Our findings suggest that Taiwan is a low-prevalence nonendemic area for HTLV-I infection. The large-scale HTLV-I screening program has decreased HTLV-I seropositivity among blood donors and is useful for preventing HTLV-I transmission via blood transfusion.

Thromboxane mediates pulmonary hypertension and lung inflammation during hyperacute lung rejection

The role of thromboxane (Tx) in hyperacute rejection of pig lung by human blood was studied in an ex vivo model, wherein lungs from juvenile piglets were perfused with fresh heparinized human blood. In this model, hyperacute lung rejection was characterized by an abrupt rise in pulmonary vascular resistance (PVR; >1 cmH2O · ml−1· min) and prolific Tx elaboration (>15 ng/ml) within 5 min and loss of function within 10 min. Although papaverine significantly blunted the rise in PVR (<0.2 cmH2O · ml−1· min), Tx production was not inhibited (>20 ng/ml), and florid tracheal edema was usually evident within 20 min. In contrast, both inhibition of Tx synthesis (Tx < 3 ng/ml) with OKY-046 and blockade of the Tx receptor with SQ-30741 (Tx > 20 ng/ml) were not only associated with significantly lower peak PVRs (<0.2 cmH2O · ml−1· min) but also with attenuated increase in lung wet-to-dry ratio and airway edema. In concert, elaboration of histamine and tumor necrosis factor was blunted, and median survival increased >10-fold to 2 h (SQ-30741) and >4 h (OKY-046). Depletion of the pig lung macrophages with dichloromethyl bisphosphonate in liposomes, but not Pall filtration of the human blood or liposomes alone, significantly inhibited Tx elaboration (<0.2 vs. >8 ng/ml for Pall filtration or liposomes) and blunted PVR elevation (<0.3 cmH2O · ml−1· min) during initial perfusion. C3a and histamine elaboration were inhibited, and median survival was significantly prolonged (>4 h). These findings implicate Tx in the inflammation associated with hyperacute lung rejection and demonstrate that pulmonary intravascular macrophages are critical to its elaboration.

The crystal structure of a novel mammalian lectin, Ym1, suggests a saccharide binding site

Ym1, a secretory protein synthesized by activated murine peritoneal macrophages, is a novel mammalian lectin with a binding specificity to GlcN. Lectins are responsible for carbohydrate recognition and for mediating cell-cell and cell-extracellular matrix interactions in microbes, plants, and animals. Glycosaminoglycan heparin/heparan sulfate binding ability was also detected in Ym1. We report here the three-dimensional structure of Ym1 at 2.5-A resolution by x-ray crystallography. The crystal structure of Ym1 consists of two globular domains, a beta/alpha triose-phosphate isomerase barrel domain and a small alpha + beta folding domain. A notable electron density of sugar is detected in the Ym1 crystal structure. The saccharide is located inside the triose-phosphate isomerase domain at the COOH terminal end of the beta-strands. Both hydrophilic and hydrophobic interactions are noted in the sugar-binding site in Ym1. Despite the fact that Ym1 is not a chitinase, structurally, Ym1 shares significant homology with chitinase A of Serratia marcescens. Ym1 and chitinase A have a similar carbohydrate binding cleft. This study provides new structure information, which will lead to better understanding of the biological significance of Ym1 and its putative gene members.

A macrophage protein, Ym1, transiently expressed during inflammation is a novel mammalian lectin

Oral infections of mice with Trichinella spiralis induce activation of peritoneal exudate cells to transiently express and secrete a crystallizable protein Ym1. Purification of Ym1 to homogeneity was achieved. It is a single chain polypeptide (45 kDa) with a strong tendency to crystallize at its isoelectric point (pI 5.7). Co-expression of Ym1 with Mac-1 and scavenger receptor pinpoints macrophages as its main producer. Protein microsequencing data provide information required for full-length cDNA cloning from libraries constructed from activated peritoneal exudate cells. A single open reading frame of 398 amino acids with a leader peptide (21 residues) typical of secretory protein was deduced and later deposited in GenBank (accession number M94584) in 1992. By means of surface plasmon resonance analyses, Ym1 has been shown to exhibit binding specificity to saccharides with a free amine group, such as GlcN, GalN, or GlcN polymers, but it failed to bind to other saccharides. The interaction is pH-dependent but Ca2+ and Mg2+ ion-independent. The binding avidity of Ym1 to GlcN oligosaccharides was enhanced by more than 1000-fold due to the clustering effect. Specific binding of Ym1 to heparin suggests that heparin/heparan sulfate may be its physiological ligand in vivo during inflammation and/or tissue remodeling. Although it shares approximately 30% homology with microbial chitinases, no chitinase activity was found associated with Ym1. Genomic Southern blot analyses suggest that Ym1 may represent a member of a novel lectin gene family.

Kappa-opioid receptor agonist suppression of HIV-1 expression in CD4+ lymphocytes

Synthetic kappa-opioid receptor (KOR) agonists have been shown to suppress HIV-1 expression in acutely infected macrophages. In the present study, we examined the effects of the KOR ligand trans-3,4-dichloro-N-methyl-N[2-(1-pyrolidinyl)cyclohexyl]benzeneaceamide methanesulfonate (U50,488) on HIV-1 expression in CD4+ lymphocytes, the main target cell of this virus. When U50,488 was added to activated CD4+ lymphocytes, HIV-1 expression was inhibited in a concentration- and time-dependent manner with maximal suppression (approximately 60%) at 10(-7) M U50,488. The KOR selective antagonist nor-binaltorphimine (nor-BNI) had no effect by itself on viral expression but blocked the antiviral property of U50,488, suggesting that U50,488 was acting via a KOR-related mechanism. Support for the involvement of KOR was provided by the findings that 34% of activated CD4+ lymphocytes were positive for KOR, using an immunofluorescence technique, and that seven additional synthetic KOR ligands also inhibited HIV-1 expression. The results of this study broaden understanding of the antiviral properties of KOR ligands to include cells outside of the nervous system and suggest a potential role for these agents in the treatment of HIV-1 infection.

Recombinant tissue factor pathway inhibitor enhances the binding of factor Xa to human monocytes

Tissue factor pathway inhibitor (TFPI) is a kunitz-type inhibitor of activated factor X (Xa). TFPI was reported to mediate Xa binding to a few of carcinoma cell lines. In this study it was observed that the Xa activity associated with human peripheral blood mononuclear cells (PBMC) incubated with Xa in the presence of recombinant TFPI (rTFPI) was much higher than with Xa alone. Xa activity on PBMC was also observed after whole blood was incubated with pre-formed Xa/TFPI complex. Further studies with flow cytometric analysis demonstrate that rTFPI enhances the binding of Xa to human monocytes. Western blot analysis showed that rTFPI was cleaved into a few of fragments after its incubation with monocytes either in the presence or absence of Xa. Based on these results and the observations reported by others, we speculate that Xa/TFPI complex may bind to human monocytes by a yet unidentified mechanism. The recovery of Xa activity from Xa/TFPI complex on PBMC may be related to the cleavage of rTFPI by Xa and/or monocyte proteases. This observation suggests a new mechanism by which monocytes become procoagulant in some pathological conditions in addition of the well known tissue factor expression on proinflammatic monocytes.

Intrafamilial transmission and risk assessment of HTLV-I among blood donors in southern Taiwan

The human T-lymphotropic virus type I (HTLV-I) is one of the important etiological agents of adult T-cell leukemia/lymphoma and of HTLV-I associated myelopathy or tropical spastic paraparesis. There is still a lack of data concerning HTLV-I transmission by seropositive carriers in Taiwan. We investigated the patterns of HTLV-I intrafamilial transmission in HTLV-I seropositive blood donors and assessed the risk factors of HTLV-I transmission in relatives of HTLV-I carriers in Taiwan. A total of twenty HTLV-I seropositive donors and their 103 relatives were enrolled. Among those 103 relatives, 40 (38.8%) were seropositive for HTLV-I. Their ages ranged from one to 70 years old with a mean age of 31.0 +/- 1.65 year-old. Three of the ten wives of male carriers were HTLV-I seropositive. However, none of the six husbands of female carriers were HTLV-I seropositive. Mother-to-child vertical transmission was found in nine of 48 (18.8%) tested. Significant risk factors of HTLV-I transmission among relatives of HTLV-I carriers were hospital admission, previous transfusion, breast feeding, anti-HCV seropositivity and female relatives of age >/= 30 with odds ratio (OR) of 9.73, 8.64, 4.36, 8.86 and 4.91, respectively (all p < 0.05). Nonsignificant risk factors of HTLV-I transmission were sharing needles, operation history, HBsAg seropositivity and male relatives of age >/= 30. Our findings suggest that mother-to-child and husband-to-wife transmissions are the important forms of intrafamilial transmission of HTLV-I in Taiwan. Screening for HTLV-I in family members of HTLV-I seropositive blood donors may be warranted.

Enhanced detection of live bacteria using a dendrimer thin film in an optical biosensor

Here we describe the detection of live Pseudomonas aeruginosa using a sensing film containing a fourth-generation hydroxy-terminated polyamidoamine (PAMAM) dendrimer (i.e., G4-OH) and SYTOX Green fluorescent nucleic acid stain. The films are configured on simple, disposable plastic coupons or optical fibers and are interrogated using a miniature fiber-optic spectrometer. SYTOX Green is generally considered a dead cell stain because it is not able to cross the membranes of live cells. In the presence of PAMAM-OH (G4-OH) in water, the bacterial cell becomes permeable to the SYTOX dye and the fluorescence is significantly enhanced. The fluorescence increases with the bacteria concentration, and the intensity at 5.4 x 10(7) cells mL(-1) is 350% higher than the liquid controls without PAMAM-OH. We also demonstrate that dendrimers stabilize the sensing film. After drying and desiccation, the SYTOX Green/PAMAM-OH films are still able to quantitatively detect P. aeruginosa in water. Incorporation of glucose into the SYTOX Green/ PAMAM-OH film may improve the homogeneity of the film and enhances the fluorescence signal an additional 11-25%.

Alteration in the expression of protein kinase C isoforms in human hepatocellular carcinoma

This study was designed to investigate the alterations of individual protein kinase C (PKC) isoforms in human liver cancer. Surgical specimens of hepatocellular carcinoma and adjacent normal tissues were extracted into cytosolic and membranous fractions. The level of membrane-bound PKCalpha in the cancer tissue was significantly lower than that in the adjacent normal tissue and consistent with the change in PKC activity. In addition, there was a significant negative correlation between PKCalpha and tumor size. In both cytosolic and membrane fractions, levels of PKCdelta and PKCzeta was significantly higher in the cancer tissue than those in the adjacent normal liver tissue. The alterations in the PKC isoforms signify their roles in the hyperproliferation in liver cancer.

Arylacetamides as peripherally restricted kappa opioid receptor agonists

Analogues of the kappa (kappa) opioid receptor agonist, ICI 199441, were prepared. Ki values for these analogues at the cloned human kappa opioid receptor ranged from 0.058 to 25 nM. Trifluoromethylaryl derivatives were potent analgesics when administered subcutaneously in the rat and were more peripherally restricted than the parent compound, ICI 199441.

Outcome of cardiopulmonary resuscitation in a pediatric cardiac intensive care unit

OBJECTIVE

To determine the eventual outcome of children with heart disease who had cardiopulmonary resuscitation (CPR) in a specialized pediatric cardiac intensive care unit (CICU), and to define the influence of any prearrest variables on the outcome.

DESIGN

A retrospective review of patients' medical records.

SETTING

A pediatric CICU of a tertiary pediatric teaching hospital.

PATIENTS AND METHODS

Patients were all children who presented with cardiopulmonary arrest and who were administered CPR in the pediatric CICU between June 1995 and June 1997. Prearrest variables such as age, diagnosis, prior cardiac surgery, and inotropic support with epinephrine, as well as cause of arrest, were evaluated.

MEASUREMENTS AND MAIN RESULTS

Thirty-two patients, ranging in age from 1 day to 21 yrs (median, 1 month), satisfied criteria for inclusion in the study group. These 32 patients had a total of 38 episodes of cardiopulmonary arrest. Twenty-five of these patients (78%) had cardiac surgery before arrest. Inotropic support with continuous infusion of epinephrine was being administered at the time of arrest in 18 of 38 (47%) arrests. These prearrest variables did not influence outcome of CPR. Of the 38 episodes of CPR, 24 episodes (63%) were successful, with 20 episodes resulting in return of spontaneous circulation and four patients being successfully placed on mechanical cardiopulmonary support. Fourteen children, including all four patients who were rescued with mechanical cardiopulmonary support, survived to discharge. At 6-month follow-up, 11 patients were still alive, with three having neurologic impairment.

CONCLUSIONS

After cardiopulmonary resuscitation in this pediatric CICU, the rate of success was 63% and the rate of survival was 42%. Prior cardiac surgery and use of epinephrine before arrest did not influence the outcome of CPR. The availability of effective mechanical cardiopulmonary support can improve the outcome of CPR.

Rapid cardiopulmonary support for children with complex congenital heart disease

BACKGROUND

Extracorporeal membrane oxygenation has limitations in children with congenital heart disease (prolonged setup times, increased postoperative blood loss, and difficulty during transport). We developed a miniaturized cardiopulmonary support circuit to address these limitations.

PATIENTS AND METHODS

The cardiopulmonary support system includes a preassembled, completely heparin-coated circuit, a BP-50 Bio-Medicus centrifugal pump, a Minimax plus membrane oxygenator, a Bio-Medicus flow probe, and a Bio-trend hematocrit/oxygen saturation monitor. Short tubing length permits a 250-mL bloodless prime in less than 5 minutes. From 1995 to 1997, 23 children with congenital heart disease were supported with this technique.

RESULTS

Overall survival to discharge was 48% (11 of 23 patients). Survival to discharge was 80% (4 of 5) in the preoperative support group, 20% (1 of 5) in the postoperative failure to wean from cardiopulmonary bypass group, 44% (4 of 9) in the group placed on support postoperatively after transfer to the intensive care unit, and 50% (2 of 4 patients) in the nonoperative group. Neonatal cardiopulmonary support survival to discharge was 46% (6 of 13 patients).

CONCLUSIONS

This pediatric cardiopulmonary support system is safe and effective. Advantages over conventional extracorporeal membrane oxygenation include rapid setup time, decreased postoperative blood loss, and simplified transport.

Stanniocalcin 1 and 2 are secreted as phosphoproteins from human fibrosarcoma cells

Stanniocalcin 1 (STC1) and stanniocalcin 2 (STC2) are two recently identified mammalian peptide hormones. STC1 plays a role in calcium and phosphate homoeostasis, while the role of STC2 is unknown. We examined a human fibrosarcoma cell line, HT1080, that has high steady-state STC1 and STC2 mRNA levels, to determine whether these proteins are secreted. Following incubation of HT1080 cells with (32)P, labelled STC1 and STC2 were found to be secreted into the medium. STC1 was phosphorylated in vitro by protein kinase C (PKC). In vitro and in vivo phosphorylation both occurred exclusively on serine and the phosphopeptide maps were similar, suggesting that PKC might be the in vivo kinase. STC2 was phosphorylated in vitro by casein kinase II (CK2), in vitro and in vivo phosphorylation were exclusively on serine and the phosphopeptide maps were indistinguishable. Phosphorylation of STC2 in intact cells resulted from the action of an ecto-protein kinase, since exogenous STC2 was phosphorylated by HT1080 cells and no phosphorylated STC2 was detectable inside the cells. The ectokinase activity was abolished by heparin and GTP could substitute for ATP as the phosphate donor, indicative of an ecto-CK2-like activity. The in vitro CK2 phosphorylation site was shown by matrix-assisted laser-desorption ionization-time-of-flight MS to be a single serine located between Ser-285 and Ser-298 in the C-terminal region of STC2. This is the first report of the secretion of STC1 or STC2 from mammalian cells. We conclude that these human fibrosarcoma cells express both STC1 and STC2 as secreted phosphoproteins in vivo, with STC2 being phosphorylated by an ecto-CK2-like enzyme.

Pediatric cardiac intensive care: current state of the art and beyond the millennium

Pediatric cardiac intensive care has emerged as a distinct clinical entity to meet the unique needs of pediatric patients with congenital and acquired heart disease. This new subspecialty demands expertise and experience in the pediatric subspecialties of cardiology, intensive care, cardiac surgery, cardiac anesthesia, neonatology, and others. Ten recent developments will have an impact on pediatric cardiac intensive care for the coming decades: 1) emergence of new patient populations; 2) new clinical methodologies in the treatment of pulmonary hypertension; 3) innovations in techniques of respiratory support; 4) expanding research of single ventricle physiology; 5) advances in the treatment of heart failure; 6) improved noninvasive imaging; 7) new directions in interventional cardiac catheterization; 8) new techniques in pediatric cardiac surgery; 9) use of computer technology and intensive care monitoring; and 10) appreciation for global economics of intensive care. Finally, a multidisciplinary approach with a team esprit de corps remains vital to a successful pediatric cardiac intensive care program.

The distribution of stanniocalcin 1 protein in fetal mouse tissues suggests a role in bone and muscle development

We previously isolated a mammalian gene STC1 that encodes a glycoprotein related to stanniocalcin (STC), a fish hormone that plays a major role in calcium homeostasis. However, the mammalian STC1 gene is expressed in a variety of adult tissues in contrast to fish where STC is expressed only in one unique gland, the corpuscles of Stannius. This suggested that STC1 may have wider autocrine/paracrine functions in mammals. In the present study, using immunocytochemistry, we showed that STC1 protein is localized in the developing bone and muscle of the mouse fetus. During endochondral bone formation, STC1 is found principally in prechondrocytes and prehypertrophic chondrocytes. During intramembranous bone formation STC1 is present in the mesenchyme that is about to undergo ossification. STC1 is also found in the myocardiocytes of the developing heart and at all stages of differentiation from myoblasts to myotube formation in developing skeletal muscle. The specific localization of STC1 to chondrocytes and muscle cells suggests a role for this protein in chondrogenic and myogenic differentiation.

The endothelial cell protein C receptor aids in host defense against Escherichia coli sepsis

The influence of the endothelial protein C receptor (EPCR) on the host response to Escherichia coli was studied. Animals were treated with 4 separate protocols for survival studies and analysis of physiologic and biochemical parameters: (1) monoclonal antibody (mAb) that blocks protein C/activated protein C binding to EPCR plus sublethal numbers of E coli (SLEC) (n = 4); (2) mAb to EPCR that does not block binding plus SLEC (n = 3); (3) SLEC alone (n = 4); and (4) blocking mAB alone (n = 1). Those animals receiving blocking mAb to EPCR plus sublethal E coli died 7 to 54 hours after challenge, whereas all animals treated with the other protocols were permanent survivors. Histopathologic studies of tissues from animals receiving blocking mAb plus SLEC removed at postmortem were compared with those animals receiving SLEC alone killed at T+24 hours. The animals receiving the blocking mAb exhibited consumption of fibrinogen, microvascular thrombosis with hemorrhage of both the adrenal and renal cortex, and an intense influx of neutrophils into the adrenal, renal, and hepatic microvasculature, whereas the tissues from animals receiving only sublethal E coli exhibited none of these abnormal histopathologic changes. Compared with the control animals, the animals receiving the blocking mAb exhibited significantly elevated serum glutamic pyruvic transaminase, anion gap, thrombin-antithrombin complex, IL-6, IL-8, and soluble thrombomodulin. The levels of circulating activated protein C varied too widely to allow a clear determination of whether the extent of protein C activation was altered in vivo by blocking protein C binding to EPCR. We conclude that protein C/activated protein C binding to EPCR contributes to the negative regulation of the coagulopathic and inflammatory response to E coli and that EPCR provides an additional critical step in the host defense against E coli. (Blood. 2000;95:1680-1686)

Recombinant human antithrombin III improves survival and attenuates inflammatory responses in baboons lethally challenged with Escherichia coli

Plasma-derived antithrombin III (ATIII) prevents the lethal effects of Escherichia coli infusion in baboons, but the mechanisms behind this effect are not clear. In the present study, we evaluated the effects of recombinant human ATIII (rhATIII) on the clinical course and the inflammatory cytokine and coagulation responses in baboons challenged with lethal dose of E coli. Animals in the treatment group (n = 5) received high doses of rhATIII starting 1 hour before an E coli challenge. Those in the control group were administered saline. Survival was significantly improved in the treatment group (P =.002). Both groups had similar hemodynamic responses to E coli challenge but different coagulation and inflammatory responses. The rhATIII group had an accelerated increase of thrombin-ATIII complexes and significantly less fibrinogen consumption compared to controls. In addition, the rhATIII group had much less severe thrombotic pathology on autopsy and virtually no fibrinolytic response to E coli challenge. Furthermore, the rhATIII group had a significantly attenuated inflammatory response as evidenced by marked reduction of the release of various cytokines. We conclude that the early administration of high doses of rhATIII improves the outcome in baboons lethally challenged with E coli, probably due to the combined anticoagulation and anti-inflammatory effects of this therapy. (Blood. 2000;95:1117-1123)

Peritonitis in the baboon: a primate model which stimulates human sepsis

The physiological, hemostatic, and immunological responses of 12 chronically instrumented conscious baboons with sepsis due to Escherichia coli peritonitis were compared with that of similarly instrumented controls. Chronic indwelling cannulae were placed in the aorta and pulmonary artery to monitor pressure, cardiac output, and obtain blood samples. At t = 0 a sterile or E. coli-laden fibrin clot containing 1.9-6.7 x 10(11) CFU/kg was introduced into the peritoneal cavity. The control animals were group 1 (n = 3). The animals with peritonitis were divided into three groups depending on their clinical response. Group 2 animals (n = 3) were clinically well at the time of sacrifice (day 14), group 3 (n = 4) survived but were obviously sick on day 14, and group 4 (n = 5) died of sepsis. Implantation of a sterile fibrin clot was well tolerated with little hemodynamic change and a transient minimal inflammatory response in group 1. Implantation of an E. coli-containing clot elicited a hyperdynamic cardiovascular response and evoked a marked inflammatory reaction and a disseminated intravascular coagulopathy. Five of 12 (42%) E. coli animals died from sepsis. In general, the physiological, hemostatic, and immunological disturbances tended to be greatest in these animals. Autopsy revealed residual peritoneal inflammation and varying degrees of inflammation in the lungs, adrenal, spleen, liver, and kidneys in all the animals that received E. coli with the inflammatory infiltrate increasing in severity from group 2 through group 4. Tissue necrosis was observed only in the latter group. We conclude that the cardiovascular, hemostatic, and immunological responses of baboons with sepsis due to E. coli peritonitis exhibit a variable course that resembles the clinical manifestations of gram-negative sepsis in humans.

Aberrant development of thymocytes in mice lacking laminin-2

In previous in vitro studies, we proposed a role for the extracellular matrix component, laminin-2, and its integrin receptor, VLA-6, in thymocyte development. The characterization of two dystrophic mouse strains with different defects in laminin-2 allowed us to examine this proposal in vivo. Mice deficient in laminin-2, dy/dy, show a significant reduction in thymus size and number of thymocytes compared to normal littermates. These mice also exhibited apparent alterations of thymic architecture. Examination of the CD4/CD8 populations in dy/dy thymi showed large relative increases in the DN (CD4- CD8-) and SP (CD4+ CD8-, CD4- CD8+) populations and a significant decrease in the DP (CD4+ CD8+) population. Further examination of the DN population for CD44 and CD25 expression showed a remarkable decrease in the more mature pre-T cell populations. Analysis of apoptosis in situ, and by flow cytometry, in dy/dy thymi revealed a significant increase in apoptotic DN thymocytes in the capsule and subcapsular regions. Interestingly, thymocyte development appeared to proceed normally in dystrophic mice expressing a mutant form of laminin-2, dy2J, as well as, in fetal and neonatal dy/dy mice. We propose that laminin-2 plays an active role in thymocyte development by delivering cell survival and differentiation signals at specific stages of development in young adult mice.

Prolongation of primate cardiac allograft survival by treatment with ANTI-CD40 ligand (CD154) antibody

BACKGROUND

We evaluated whether a humanized anti-CD154 antibody (hu5c8) prolongs primate cardiac allograft survival.

METHODS

Heterotopic cardiac allografts were performed between MHC class II-mismatched cynomolgus monkeys. Survival was compared between groups treated with a perioperative dosing of hu5c8 (group 1; n=6), sustained dosing with hu5c8 (group 2; n=3), and control regimens (n=4). All recipients received fresh donor-specific transfusions during surgery.

RESULTS

Median graft survival was 49 days (range 14 to 56) in group 1 and 106 days (range 56 to 245) in group 2, compared with 5 days (range 5 to 6) for controls (P<0.05 for all comparisons). Lymphocytic infiltrates were often present in hu5c8-treated grafts with stable contractility. Donor-specific mixed lymphocyte reaction was generally preserved. Vasculitis and cellular intimal proliferation were prevalent in rejected grafts but occurred later and were less prevalent in group 2.

CONCLUSIONS

Anti-CD154 antibody markedly prolongs the survival of cardiac allografts in primates and is well tolerated. Sustained dosing with hu5c8 yielded improved survival and may be associated with a lower incidence of vascular pathology. We conclude that hu5c8 therapy is an effective approach for inhibiting acute cardiac allograft rejection in primates.

Alternative splicing regulates the production of ARD-1 endoribonuclease and NIPP-1, an inhibitor of protein phosphatase-1, as isoforms encoded by the same gene

ARD-1 is an endoribonuclease identified initially as the product of a human cDNA that complements mutations in rne, a gene that encodes Escherichia coli ribonuclease E. NIPP-1 was identified in bovine nuclear extracts as an inhibitor of protein phosphatase-1. Earlier work has shown that the protein-coding sequence of ARD-1 is identical to the carboxy-terminal third of NIPP-1. However, whether ARD-1 is present in eukaryotes as a distinct entity has been unclear, as neither ARD-1-specific transcripts nor ARD-1 protein were detected in mammalian cells in earlier studies. Here we show that ARD-1 exists in human cells as a discrete protein, and that the ARD-1 and NIPP-1 peptides are isoforms encoded by a single gene and the same alternatively spliced precursor RNA. A retained intron containing multiple translation stop codons that are configured to terminate translation and initiate nonsense-mediated decay, limits the production of cellular ARD-1 protein. Our results establish the process by which functionally disparate ARD-1 and NIPP-1 peptides are generated from the protein-coding sequence of the same gene in human cells.

Immunohistologic evaluation of mechanisms mediating hyperacute lung rejection, and the effect of treatment with K76-COOH, FUT-175, and anti-Gal column immunoadsorption

Although most investigators agree that lung dysfunction occurs rapidly in various pig-to-primate hyperacute lung rejection (HALR) models, the basic mechanisms mediating this phenomenon remain in question. Here we describe an immunohistochemical method for assessment of mechanisms driving HALR. Using an established model wherein piglet lungs are perfused ex vivo with human blood, six experimental groups (K76 COOH; FUT-175; K76 with FUT; anti-alpha-Gal column adsorption; column with FUT; and column with K76) and two control groups (unmodified human blood; autologous pig blood) were studied. Each lung was biopsied serially during perfusion, and assessed using an immunohistochemical technique, with vWF staining as an internal control to quantitate binding of human IgM, IgG, C3, C5b-9, properdin, and C1q. The effect of each treatment and subsequent lung perfusion on IgG and IgM anti-alpha-Gal titers(by ELISA) and on pig endothelial cell cytotoxicity were correlated with histologic findings. We found that [1] the classical complement activation pathway was activated, as has been shown for other pig organs in primate or human blood environments [2]; alternative complement pathway activation is also seen, which has not been described for other organs in pig-to-primate models, but only in the context of classical pathway activation; and [3] anti-Gal column absorption, pharmacologic inhibition of complement, or combination therapy each was associated with histologic evidence of partial protection, consistent with what would be predicted for each intervention. Further, immunohistologic differences correlated with physiologic outcomes [8] and with antibody assay results, and revealed that treatments used were incompletely effective. Our data suggest that more complete inhibition of antibody- and complement-driven pathways than was achieved in these experiments will be necessary to prevent the antibody and complement-mediated facets of hyperacute lung rejection. This immunohistologic technique may also help us identify additional pathogenic mechanisms important to eventual clinical application of pig-to-human lung xenografts.

Seroprevalence of CMV antibodies in a blood donor population and premature neonates in the south-central Taiwan

Infection of cytomegalovirus (CMV) via contaminated blood may endanger immunocompromised patients that require transfusion therapy. The aim of this study is to determine the prevalence of CMV antibodies in the blood donor population in Southern-central Taiwan. A total of 1800 consecutive sera, obtained from Tainan Blood Center of Chinese Blood Services Foundation (CBSF), were tested for CMV antibodies by two commercial enzyme immunoassays (EIAs). Of the sera tested, 150 (8.3%) were found to be CMV seronegative. The frequency of CMV seropositivity revealed no significant difference between male and female donors. The frequency of CMV seronegativity showed a stepwise decrease with the increase of donor age. In addition, the prevalence of HBsAg, antibodies to hepatitis C virus (anti-HCV), antibodies to human immunodeficiency viruses type 1 and 2 (anti-HIV 1 + 2) and antibodies to human T-cell lymphotropic viruses type I and II (anti-HTLV I/II) were compared between CMV seropositive and seronegative groups. Our results showed that there was no significant difference in seroprevalence of these markers between CMV seropositive and seronegative groups. Our findings also showed that six out of twenty (30.0%) premature neonates were CMV-seropositive. These premature specimens and those EIA discrepancy samples were confirmed by specific nucleic acid amplification using polymerase chain reaction (PCR). Our results suggest that a program which aims to supply CMV seronegative blood or blood components to the patients, should not solely depend on current antibody screening methods in an area where CMV infection is highly endemic. Amendments such as PCR testing, leukocyte reduction by filtration before transfusion may be more practical.

Impact of respiratory syncytial virus infection on surgery for congenital heart disease: postoperative course and outcome

OBJECTIVES

a) To describe the postoperative course and outcome of cardiac surgery in children with recent respiratory syncytial virus (RSV) infection; and b) to evaluate whether timing of surgery has any impact on the outcome.

DESIGN

Retrospective case series.

SETTING

Intensive care unit and medical and surgical wards of a teaching pediatric hospital.

PATIENTS

Twenty-five children (aged 25 days to 3.5 yrs; median, 4 months) with congenital heart disease who had cardiac surgery within 6 months after RSV infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We reviewed the clinical course and outcome of all patients. The cardiac diagnoses included ventricular septal defect (n = 11), tetralogy of Fallot (n = 3), atrioventricular canal (n = 3), and others (n = 8). Thirteen patients had surgery during the same admission as RSV infection (group I), and 12 patients had surgery electively after being discharged to home after RSV infection (group II). Two patients in group I died; both of these patients had undergone total repair of tetralogy of Fallot within 2 wks after admission for RSV infection. Postoperative complications in group I patients included pulmonary hypertension (n = 5), adult respiratory distress syndrome (n = 1), tracheal stenosis (n = 1), left ventricular dysfunction (n = 1), pericardial effusion (n = 1), secondary bacterial or fungal infection (n = 7), and deep venous thrombosis (n = 1). Of all group I patients, the ones who were operated on early appeared to be at higher risk for complications, especially for postoperative pulmonary hypertension. No patient in group II died, and only two patients had minor complications (one had reactive airway disease, and the other had a transient superior vena cava syndrome after a bidirectional Glenn operation).

CONCLUSIONS

Cardiac surgery performed during the symptomatic period of RSV infection is associated with a high risk of postoperative complications, especially postoperative pulmonary hypertension. These complications appeared to be more frequent and of greater severity in patients who had earlier surgery compared with those who had later surgery. More studies are needed regarding the proper timing of cardiac surgery in patients with congenital heart disease and RSV infection.

Expression and localisation of stanniocalcin 1 in rat bladder, kidney and ovary

Bony fish use the glycoprotein hormone stanniocalcin (STC) to counteract hypercalcaemia. This is achieved through dual mechanisms involving gill calcium uptake inhibition and stimulation of renal inorganic phosphate reabsorption. Human STC (hSTC-1) shows considerable homology with both rat and mouse STC (mSTC) and their mRNA is expressed in a wide range of tissues. In fish, STC is produced by endocrine glands known as the corpuscles of Stannius but in mammals the widespread expression is suggestive of a paracrine rather than an endocrine role. In order to determine the distribution and strucutral characteristics of hSTC-1, the recombinant protein was expressed in bacteria, purified by metal-ion affinity chromatography, and a study was made of the likely epitopes for raising an antibody. This novel hSTC-1 antibody was used to test the purification protocol. Since the role of mammalian STC is largely unknown, the specific distribution of STC needed to be addressed. To test the specificity of the antibody, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)/Western blotting was undertaken in homogenised rat bladder, ovary and kidney.

Protein kinase C isoforms during the development of deciduomata in pregnant rats

In this study, we determined the expression of protein kinase C (PKC) isoforms during pregnancy. At pregnant duration, PKC alpha was down-modulated in the deciduomata but not in the myometrium. Down-modulation was compatible with the increase in cell mitosis, which reached a maximum at 8-9 days. On the other hand, PKC zeta was not down-modulated. It was increased both in the cytosolic and particulate fractions of the deciduomata, and paralleled the frequency of decidual cell mitosis. The other PKC isoform of delta was also increased, but it was associated with the cell regression. Therefore, these findings confirmed that the variable expression of PKC isoforms in decidualizing tissue may be involved in the modulation of decidual cell growth.

Impact of flumazenil on recovery after outpatient endoscopy: a placebo-controlled trial

BACKGROUND

Flumazenil is an imidazobenzodiazepine that blocks the central effects of benzodiazepines by competitive interaction at the receptor level. In this study we assessed the impact of flumazenil use on postsedation observation time in outpatients undergoing endoscopy.

METHODS

Sixty outpatients received midazolam for conscious sedation and were randomized after endoscopy to receive intravenous flumazenil (0.1 mg/mL) or placebo until awake or a total of 10 mL was given. All patients were assessed using various psychomotor and cognitive tests at baseline and at 5, 15, 30, 45 and 60 minutes after flumazenil or placebo was administered.

RESULTS

The two groups were similar in age, gender, midazolam dose (mg/kg), vital signs, and baseline parameters. The average dose of flumazenil given was 0.41 mg. Sedation scores returned to presedation levels earlier in the flumazenil group, with significant differences compared to placebo at 5 minutes (84.6% vs. 24.2%), 15 minutes (88. 5% vs. 57.6%) and 30 minutes (96.2% vs. 66.7%). Other parameters tested were not significantly different for patients receiving placebo compared to those given flumazenil. Sedation scores returned to baseline earlier than other psychomotor and cognitive tests in both groups. Flumazenil reduced the mean observation time from 23.5 minutes to 8.3 minutes (p < 0.0005), a difference of 15.2 minutes (64.7%) based on sedation score.

CONCLUSIONS

Flumazenil significantly reduces postsedation observation time. Actual cost savings will vary depending on staff and facility capacity, patient volume, flumazenil cost, and unit cost of observation time.

Adverse hemodynamic effects observed with inhaled nitric oxide after surgical repair of total anomalous pulmonary venous return

The following is a case report of a 1-month-old patient who developed adverse hemodynamic sequelae during the use of nitric oxide (NO) in the postoperative period for pulmonary hypertension after correction of total anomalous pulmonary venous return. At the time of diagnosis, the patient had evidence of systemic right ventricular pressures estimated by continuous-wave Doppler. He was sedated and paralyzed for hyperventilation in preparation for surgery and underwent pulmonary vein confluence to left atrial anastomosis. Postoperative pulmonary hypertension was managed by hyperventilation, sedation, and paralysis until a sudden onset of systemic-level pulmonary pressure required NO therapy. Satisfactory results were obtained in minutes, but a rebound pulmonary hypertension occurred with concomitant systemic hypertension and no radiographic changes. We suspected left atrial hypertension secondary to a sudden increase in pulmonary blood flow to an noncompliant left ventricle. Discontinuation of NO resulted in stabilization of the hemodynamic profile of the patient and he continued to be managed with paralysis, hyperventilation, and sedation. Based on this experience we suggest that NO should be used with caution in patients with obstructive lesions at the atrial level prior to surgery (mitral valve stenosis and cor triatriatum) or in patients with a poorly compliant left ventricle (cardiomyopathy and left ventricular dysfunction). These entities are unable to tolerate a sudden increase in pulmonary blood return thus creating paradoxical pulmonary hypertension.

Characterization of the baboon responses to Shiga-like toxin: descriptive study of a new primate model of toxic responses to Stx-1

The baboon response to intravenous infusion of Shiga toxin 1 (Stx-1) varied from acute renal failure, proteinuria, hyperkalemia, and melena with minimal perturbation of host inflammatory and hemostatic systems (high-dose group, 2.0 microg/kg; n = 5) to renal failure with hematuria, proteinuria, thrombocytopenia, schistocytosis, anemia, and melena (low-dose group, 0.05 to 0.2 microg/kg; n = 8). Both groups exhibited renal shutdown and died in 57 hours or less. Both groups produced urine that was positive for tumor necrosis factor and interleukin-6 although neither of these cytokines was detectable (</=5 ng/ml) in the general circulation. Light and electron microscopy showed organelle disintegration and necrosis of the renal proximal tubular epithelium and of the intestinal mucosal epithelium at the tips of the microvilli, both of which were previously shown to bear Gb3 receptors. The renal distal tubular epithelium was spared. The renal proximal tubular epithelial changes were accompanied by swelling of visceral epithelial cells (podocytes) and by swelling and detachment of endothelial cells of the glomerular capillaries. In addition, all of the animals receiving low-dose Stx-1 showed microvascular fibrin deposition and thrombosis in renal glomerular and peritubular capillaries in association with a fall in hematocrit and platelet count and a rise in schistocyte count. The gastrointestinal villous tip lesions were accompanied by varying degrees of mucosal and submucosal congestion, hemorrhage, or necrosis. Electron microscopic images of cerebral cortex and cerebellum showed diffuse unraveling of myelin sheaths with occasional disintegration of neuronal cell bodies. In contrast to the gastrointestinal mucosal and renal proximal tubular epithelium, the Gb3 receptor glycolipid of the renal glomerular and neuronal tissues as determined using toxin overlay thin-layer chromatography plates was below the limit of detection (<13 pM/g wet tissue). We conclude that, depending on the status of the host and amount of toxin infused, Stx-1 can produce a variety of responses ranging from damage to cells carrying the Gb3 receptor (renal proximal tubular epithelial cells and gastrointestinal mucosa) to damage to renal glomerular tissues with microvascular thrombosis as a result of the host's inflammatory response localized to the kidney. We conclude that this thrombotic coagulopathy arises from local changes in the kidney because the appearance of host inflammatory mediators was limited to the urine. This suggests that the initial host response is localized in the kidney, and that the systemic thrombocytopenia, anemia, and schistocytosis may arise secondarily.