Characterization of an immunosuppressive anti-CD40 ligand monoclonal antibody

The interaction between CD40 ligand (CD40L) and its counter-receptor CD40 is critically important in T- and B-cell costimulation and generation of the humoral immune response. But several questions still remain unsolved, particularly in the human in vivo system. To clarify the precise function of CD40L and develop an immunosuppressive agent, we have generated a murine monoclonal antibody (MAb), 2B2 specific for human CD40L. The specificity of this MAb for human CD40L was verified by enzyme-linked immunoadsorbent assay (ELISA) and flow cytometry. MAb 2B2 immunoprecipitated proteins of molecular weight 35 and 28 kD on human peripheral blood lymphocytes (PBLs) stimulated with phorbol 12-myristate-13-acetate (PMA) plus ionomycin. Then we have studied the biological effect of MAb 2B2 in severe combined immunodeficiency (SCID) mice reconstituted with human PBLs. The data showed that this MAb strongly suppressed human IgG production of human B cells transplanted in SCID mice, indicating that this MAb 2B2 could be used to regulate unwanted immune responses associated with autoimmune disease. Then we analyzed the sequence of MAb 2B2. The 2B2 heavy chain variable region (VH) and light chain variable region (VL) genes were cloned using PCR. The cloned VH gene coded for 123 amino acid residues and belonged to the subgroup III(D). The VL gene coded for 126 amino acid and belonged to the subgroup V. Collectively, these results will be used to develop an immunosuppressive chimeric or humanized anti-CD40L antibody.

Isoform expression of Na+-K+-ATPase alpha-subunit in gills of the teleost Oreochromis mossambicus

Three isoform-specific antibodies, 6F against the alpha1-isoform of the avian sodium pump, HERED against the rat alpha2-isoform, and Ax2 against the rat alpha3-isoform, were used to detect the expression of Na+-K+-ATPase alpha-subunits in gills of a teleost, the tilapia (Oreochromis mossambicus). Tilapia gill tissue showed positive reactions to antibodies specific for alpha1- and alpha3-isoforms. The results of immunoblots were converted to numerical values (relative intensities) by image analysis for comparisons. Relative amounts of alpha1-like isoform alone and consequently the ratio of alpha1-like to alpha3-like isoforms were higher in gills of seawater-adapted tilapia than in those of freshwater-adapted ones, indicating that the two isoforms respond differently to environmental salinities. In the subsequent immunocytochemical experiments, gill mitochondria-rich cells were demonstrated to immunoreact with antibodies specific for alpha1- and alpha3-isoforms. alpha1-like and alpha3-like isoforms of gill Na+-K+-ATPase are suggested to be involved in the ion- and osmoregulation mechanisms in tilapia. Moreover, differential expressions of two isoforms may be associated with different functions, secretion and uptake of ions and acid-base regulation, in gills of seawater- and freshwater-adapted tilapia.

Lhermitte-Duclos disease: first report in Taiwan

We report a case of Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum), an uncommon disorder of uncertain pathogenesis characterized by disarrangement of the normal cerebellar laminar cytoarchitecture. A 40-year-old man was admitted because of vomiting and syncope of a few days' duration, and a 2-month history of intermittent headaches and unsteady gait. A computed tomographic scan of the patient's head showed obstructive hydrocephalus due to displacement of the fourth ventricle by a large, nonenhancing cerebellar mass. The magnetic resonance images of the brain also revealed a space-occupying lesion within the right cerebellum with unusual septation. After surgery, the histologic examination confirmed the diagnosis of Lhermitte-Duclos disease. This is the first report of Lhermitte-Duclos disease in Taiwan.

Supraventricular arrhythmia in patients having noncardiac surgery: clinical correlates and effect on length of stay

BACKGROUND

Few recent data are available on risk factors for perioperative supraventricular arrhythmia (SVA) after noncardiac surgery or on the effect of SVA on clinical outcomes.

OBJECTIVE

To determine the incidence, clinical correlates, and effect on length of stay of perioperative SVA in patients having major noncardiac surgery.

DESIGN

Prospective cohort study.

SETTING

Urban tertiary care teaching hospital.

PARTICIPANTS

4181 patients 50 years of age or older who had major, nonemergency, noncardiac procedures and were in sinus rhythm at the preoperative evaluation.

MEASUREMENTS

Preoperative clinical data, postoperative enzyme data, serial electrocardiograms, and clinical outcomes were collected prospectively. Outcomes were 1) SVA that persisted or led to treatment and 2) increase in length of stay attributable to SVA.

RESULTS

Perioperative SVA occurred in 317 patients (7.6%); it occurred in 83 patients (2.0%) during surgery and in 256 (6.1%) after surgery. Independent preoperative correlates of SVA were male sex (odds ratio [OR], 1.3 [95% CI, 1.0 to 1.7]), age 70 years or older (OR, 1.3 [CI, 1.0 to 1.7]), significant valvular disease (OR, 2.1 [CI, 1.2 to 3.6]), history of SVA (OR, 3.4 [CI, 2.4 to 4.8]) or asthma (OR, 2.0 [CI, 1.3 to 3.1]), congestive heart failure (OR, 1.7 [CI, 1.1 to 2.7]), premature atrial complexes on preoperative electrocardiography (OR, 2.1 [CI, 1.3 to 3.4]), American Society of Anesthesiologists class III or IV (OR, 1.4 [CI, 1.1 to 1.9]), and type of procedure: abdominal aortic aneurysm (OR, 3.9 [CI, 2.4 to 6.3]) or abdominal (OR, 2.5 [CI, 1.7 to 3.6]), vascular (OR, 1.6 [CI, 1.1 to 2.4]), and intrathoracic (OR, 9.2 [CI, 6.7 to 13]) procedures. Among patients who had intrathoracic surgery, those receiving digoxin were at lower risk (OR, 0.2 [CI, 0.04 to 0.8]) for SVA than those not receiving digoxin. Patients with perioperative acute cardiac and noncardiac events had high relative risks for SVA. Supraventricular arrhythmia was associated with a 33% increase in length of stay after adjustment for other clinical data (P < 0.001).

CONCLUSIONS

In this cohort, SVA was common after noncardiac surgery and was associated with prolonged length of stay.

Expression of nerve growth factor and trkA after transient focal cerebral ischemia in rats

BACKGROUND AND PURPOSE

In vitro studies have shown that nerve growth factor (NGF) is protective to cortical neurons against various insults. However, the role of NGF in relation to its high-affinity trkA receptor in the cortical neurons has not been well discussed. In this experiment, we studied the possible involvement of the NGF/receptor system in the ischemic injury of cortical neurons after focal cerebral ischemia in rats.

METHODS

Male Wistar rats received right middle cerebral artery occlusion of 90 minutes' duration. The rats were decapitated at different reperfusion time points: hour 4 and days 1, 3, 7, and 14 of recirculation. Brain sections at the level of striatum were immunostained against NGF, trkA, glial fibrillary acidic protein (GFAP), and stress protein HSP70. Double immunostaining against NGF and GFAP was also performed. Optical density of NGF immunoreactivity in the ischemic and nonischemic cortexes was compared between sham-control and ischemic animals.

RESULTS

In the sham-control rats, NGF immunoreactivity was present in the cortical and striatal neurons. However, beginning at hour 4 after recirculation, there was a significant decrease of NGF in the ischemic cortex and striatum. Beginning at day 1, NGF was absent completely in the infarcted striatum and cortex. However, in the peri-infarct penumbra area, despite a decrease in NGF at hour 4 and day 1, NGF recovered beginning at day 3 and returned almost to the sham-control level at day 14. In the nonischemic cortex, NGF increased beginning at hour 4, peaked at day 7, and returned almost to the sham-control level at day 14. The trkA and HSP70 immunoreactivities were not present in the sham-control cortex. However, trkA was induced at hour 4 in the ischemic cortex and at days 1 and 3 in the peri-infarct penumbra cortex. The HSP70 was induced at days 1 and 3 in the peri-infarct penumbra area. Double immunostaining showed that the number of GFAP-positive cells increased gradually, and NGF immunoreactivity in the GFAP-positive cells became gradually intense after ischemia.

CONCLUSIONS

Our study demonstrated a temporal profile of NGF and trkA in the ischemic cortex and NGF expression by reactive astrocytes. Our data suggest that the NGF/receptor system may play a role in the astrocyte/neuron interaction under certain pathological conditions, such as focal cerebral ischemia.

Cardiac troponin I as a predictor of major cardiac events in emergency department patients with acute chest pain

OBJECTIVES

We sought to evaluate the diagnostic and prognostic value of cardiac troponin I (cTnI) in emergency department (ED) patients with chest pain.

BACKGROUND

Although cTnI has been shown to correlate with an increased risk for complications in patients with unstable angina, the prognostic significance of this assay in the heterogeneous population of patients who present to the ED with chest pain is unclear.

METHODS

cTnI and creatine kinase-MB fraction (CK-MB) mass concentration were collected serially during the first 48 h from onset of symptoms in 1,047 patients > or =30 years old admitted for acute chest pain. Sensitivity, specificity and receiver operating characteristic curves were calculated for cTnI and CK-MB collected in the first 24 h.

RESULTS

The sensitivity, specificity and positive predictive value of cTnI for major cardiac events were 47%, 80% and 19%, respectively. Among patients were who ruled out for myocardial infarction, cTnI was elevated in 26% who had major cardiac complications compared with 5% for CK-MB; the positive predictive value for an abnormal cTnI result was 8%. Elevated cTnI in the presence of ischemia on the electrocardiogram was associated with an adjusted odds ratio of 1.8 (95% confidence interval 1.1 to 2.9) for major cardiac events within 72 h. Among patients without a myocardial infarction or unstable angina, cTnI was not an independent correlate of complications.

CONCLUSIONS

In patients presenting to the ED with acute chest pain, cTnI was an independent predictor of major cardiac events, However, the positive predictive value of an abnormal assay result was not high in this heterogeneous cohort.

Capsaicin activates heat loss and heat production simultaneously and independently in rats

Subcutaneous administration of capsaicin (5 mg/kg) immediately increased the temperature of the tail skin (Tsk) for 2 h in urethan-anesthetized rats, suggesting an increase in heat loss. O2 consumption, an index of heat production, also immediately increased after the capsaicin injection, and this increase lasted for >10 h. Colonic temperature (Tco) decreased within 1 h after the injection, and this decrease was followed by a long-lasting hyperthermic period. Adrenal demedullation largely attenuated the capsaicin-induced increase in O2 consumption, and sympathetic denervation of the interscapular brown adipose tissue partly attenuated the increase in O2 consumption. However, capsaicin-induced heat loss was normal in these rats. In rats with cutaneous vasodilation maximized by warming and administration of hexamethonium, capsaicin did not further increase Tsk but normally induced heat production, and Tco gradually rose without a hypothermic period. Thus capsaicin simultaneously increased heat loss and heat production, and inhibition of one response did not affect the other. These findings suggest that capsaicin simultaneously activates independent networks for heat loss and heat production.

Altered cocaine potency in the nucleus accumbens following 7-day withdrawal from intermittent but not continuous treatment: voltammetric assessment of dopamine uptake in the rat

Using in vitro fast scan cyclic voltammetry, we measured cocaine potency for inhibiting dopamine uptake/clearance in accumbens slices 7 days after withdrawal from chronic cocaine pretreatments. Rats were pretreated with 40 mg/kg per day for 14 days, either via continuous osmotic minipumps or by once-daily injections. The cocaine potency was subsequently assessed for endogenous and exogenous dopamine applied via single-pulse electrical stimulation and caged-dopamine photolysis, respectively. Under baseline conditions, no differences in either endogenous or exogenous dopamine kinetics were observed in the two cocaine pretreatment groups. In contrast, the potency of bath-applied cocaine for inhibiting endogenous dopamine uptake was enhanced in the intermittent injection group with no change in the continuous infusion group. The selective increase in the cocaine potency following injections was also demonstrable for clearance of photo-applied DA. The enhanced cocaine potency in the accumbens slices following 7 days of withdrawal is consistent with the residual sensitization to cocaine-induced locomotion following daily cocaine injections. Behavioral tolerance following continuous infusion, on the other hand, may be mediated via a mechanism distinct from altered dopamine uptake.

Distribution of HIV type 1 (HIV-1) in blood components: detection and significance of high levels of HIV-1 associated with platelets

BACKGROUND

Although inactivation of enveloped viruses transmitted by plasma derivatives has been successful, no methods for virus inactivation or removal have been established for platelet concentrates or red cell (RBC) components. Relatively little is known regarding the extent or significance of virus interactions with the cellular constituents in these components.

STUDY DESIGN AND METHODS

Units of whole blood were collected from six HIV type 1 (HIV-1)-positive, asymptomatic individuals and separated into peripheral blood mononuclear cells (PBMNCs), cell-free plasma, white cell-reduced platelet concentrate, and white cell-reduced RBCs. DNA and RNA polymerase chain reaction and virus culture methods were used to study the compartmentalization of HIV-1 immediately after component preparation and after storage.

RESULTS

As expected, HIV DNA and infectious virus were detected in fresh blood and in PBMNCs, and virion-associated RNA was detected in fresh plasma from all six donors. The levels of viral nucleic acids in these preparations remained relatively stable with 4 degrees C storage, whereas infectivity of PBMNCs was rapidly lost. Washed RBCs tested negative for HIV in all assays at all time points. Platelets retained high levels of HIV RNA (but not infectivity) after extensive washing, as well as after storage at 4 and 22 degrees C. High-level platelet-associated HIV-1 was also demonstrated in samples collected during early seroconversion. Periseroconversion and postseroconversion levels of platelet-associated HIV-1 correlated with the level of plasma viremia and with the rate of progression to AIDS. Cell-free virus from donor plasma and tissue culture fluid rapidly and firmly attached to platelets from noninfected donors. Infectivity of tissue culture virus bound to platelets was demonstrated in vitro.

CONCLUSION

Significant levels of HIV-1 are associated with platelets during all stages of infection. Platelet-associated HIV could either mediate virus clearance or facilitate virus dissemination and expanded tropism. Finally, virus inactivation research must address virus associations with platelets.

CCR5 coreceptor utilization involves a highly conserved arginine residue of HIV type 1 gp120

The seven-transmembrane CCR5 was recently found to double as a coreceptor for a genetically diverse family of human and nonhuman primate lentiviruses. Paradoxically, the main region of the envelope protein believed to be involved in CCR5 utilization was mapped to hypervariable region 3, or V3, of the envelope glycoprotein gp120. In this study, we addressed the question of whether functional convergence in CCR5 utilization is mediated by certain V3 residues that are highly conserved among HIV type 1 (HIV-1), HIV type 2, and simian immunodeficiency virus. Site-directed mutagenesis carried out on three such V3 residues revealed that the Arg-298 of HIV-1 gp120 has an important role in CCR5 utilization. In contrast, no effect was observed for the other residues we tested. The inability of Arg-298 mutants to use CCR5 was not attributed to global alteration of gp120 conformation. Neither the expression, processing, and incorporation of mutant envelope proteins into virions, nor CD4 binding were significantly affected by the mutations. This interpretation is further supported by the finding that alanine substitutions of five residues immediately adjacent to the arginine residue had no effect on CCR5 utilization. Taken together, our data strongly suggests that the highly conserved Arg-298 residue identified in the V3 of HIV-1 has a significant role in CCR5 utilization, and may represent an unusually conserved target for future anti-viral designs.

Predictive value of creatine kinase (CK)-MB for diagnosis of acute myocardial infarction after major noncardiac surgery

BACKGROUND

The aim of this study was to provide insight into the interpretation of CK-MB data after major noncardiac surgery.

METHODS

Some 3,321 patients who underwent major non-emergent noncardiac procedures (orthopedic 31%, intrathoracic 12%, vascular 22%, other 35%) were studied. All patients had at least two CK samples measured postoperatively.

RESULTS

Acute myocardial infarction was diagnosed in 43 (1.3%) patients using study criteria including CK-MB and electrocardiographic data. All of the various threshold values of peak CK-MB values and peak CK-MB as a percentage of total CK had poor positive predictive values because of high false positive rates and the low rate of acute myocardial infarction.

CONCLUSION

These data demonstrate the need for markers of myocardial injury with greater cardiac specificity after noncardiac surgery.

Purification and characterization of a novel levanoctaose-producing levanase from Pseudomonas strain K-52

Levan-assimilating micro-organisms from soil samples were screened for levanoligosaccharide-generating enzyme production. The isolated strain K-52 produced an extracellular levanoctaose-generating enzyme and was identified as belonging to genus Pseudomonas. The levanase was purified to homogeneity by (NH4)2SO4 fractionation and successive column chromatography on DEAE-cellulose, phenyl-Toyopearl 650 M, Sephadex G-100 and hydroxyapatite. The molecular mass of the enzyme was estimated as approx. 38 kDa by both SDS/PAGE and gel filtration, and its isoelectric point was approx. pH 4.8. The optimum temperature and pH for the enzyme reaction were 35 and 7.0 respectively. The enzyme was stable at a pH range of 6.0-9.0 at 4 degrees C and up to 40 degrees C at pH 6.8. The enzyme activity was inhibited by Fe2+, Cu2+, Hg2+ and Ag2+. The levanase was specific toward 2,6-beta-D-fructosidic linkages of levan and did not hydrolyse other polysaccharides such as inulin and dextran. Chemical modification on the levanase suggested that cysteine and histidine residues are essential for enzyme activity. The levanoctaose liberated by levanase reaction was used selectively only by the intestinal beneficial micro-organisms, such as Bifidobacterium and Lactobacillus spp.

Effects of blood flow and venous network on the survival of the arterialized venous flap

The purpose of this study was to evaluate further factors that could explain the survival mechanism in the arterialized venous flap. The authors used 16 canines to investigate the survival rate and pattern of the arterialized venous flap and compared the results with those of the conventional saphenous flap. The number and distribution of draining veins in the arterialized venous flap group were varied to observe their impact on the survival rate and pattern. Gross examination of venous network, blood gas, venogram, blood pressure, and histologic study were also carried out. Although there was no significant difference in final survival rate between conventional flap and arterialized venous flap with two efferent veins (p > 0.01), that of the arterialized venous flap increased significantly as the number of draining veins increased. Blood gas analysis showed that more effective oxygen consumption took place when the number of draining veins increased. By measuring the blood flow and volume at 8 hours after the operation with a laser Doppler flowmeter, it was possible to predict the necrosis of the arterialized venous flap. Attachment to a high pressure arterial blood flow system induced smooth muscle proliferation and neogrowth of elastic fibers in the veins. Furthermore, progressive narrowing of the lumen hastened the development of a collateral circulation, demonstrated on a venogram by the tortuous vessels and neovascularization up to the flap margin. To make it possible to predict and achieve complete survival of the arterialized venous flap, the following criteria must be considered: (a) an arterialized venous flap should be designed to contain most of the venous network in the center, (b) the arterial inflow has to be anastomosed to one afferent vein, (c) two or more efferent veins should drain the arterialized venous flap.

The effect of prior dural puncture on cerebrospinal fluid sufentanil concentrations in sheep after the administration of epidural sufentanil

Sufentanil is a highly lipid soluble opioid that provides potent analgesia when administered in the subarachnoid space. Unfortunately, the penetration of sufentanil into the cerebrospinal fluid (CSF) after epidural administration is poor, and limits its effectiveness for epidural analgesia. Dural puncture may enhance the movement of epidural sufentanil into the subarachnoid space and increase its effectiveness. To determine whether the administration of epidural sufentanil adjacent to a dural puncture results in significantly greater CSF concentrations, 18 adult ewes were studied. Animals in the control group had an epidural catheter placed at the superior border of the pelvis without dural puncture. Animals in the study group had an epidural catheter placed, followed by a dural puncture performed using an 18-gauge Touhy needle. The dural puncture was performed one interspace cephalad to the epidural catheter. One hour after dural puncture, each animal received a loading dose of 0.35 microg/kg of sufentanil (5 microg/mL) through the epidural catheter, followed by an infusion of epidural sufentanil 0.15 microg x kg(-1) x h(-1) for a period of 4 h. After 4 h, CSF was sampled from a site one interspace caudad to the epidural catheter as well as at the cisterna magna. The mean CSF concentration of sufentanil at the level of the pelvis for animals with a dural puncture was 12.1 +/- 3.0 ng/mL compared with 1.8 ng/mL in controls with intact dura. Sufentanil concentrations at the cisterna magna were below the level of detection (0.08 ng/mL) for all animals in both groups. We conclude that an 18-gauge dural puncture significantly increases movement of sufentanil from the epidural to the intrathecal space. This increase in sufentanil concentration at the level of the pelvis was not associated with detectable levels of sufentanil at the brainstem.

IMPLICATIONS

This study addresses the effect of dural puncture on spinal fluid concentrations of sufentanil after epidural administration. A sheep model was used to measure drug concentrations in the spinal fluid at the levels of the pelvis and brainstem after epidural administration. Dural puncture significantly enhanced movement of sufentanil into the spinal fluid at the level of the pelvis, but brainstem concentrations were below the level of detection. Analgesic concentrations of spinal sufentanil in the clinical setting, as well as brainstem concentrations associated with respiratory depression, have yet to be defined.

Purification and cloning of glyoxalase II from rat liver

Glyoxalase (GLO) II, which is a component of GLO system and catalyze the conversion of S-lactoyl-glutathione to D-lactate, was purified 1488 fold from rat liver by two steps of Affigel blue and carbobenzoxyglutathione-Sepharose 4B affinity chromatography. The molecular weight of the enzyme was estimated to be 29 kDa which is similar to those from other species. The sequence of N-terminal 9 amino acid residues was determined to be MGIRLLPAT. This was then used to synthesize degenerative primers. cDNA clone was isolated by first synthesizing cDNA from RNA and then PCR amplification. The sequence of cDNA clone was determined by serial sequencing analysis.

Early indicators of prognosis in upper gastrointestinal hemorrhage

OBJECTIVE

Endoscopy allows accurate risk stratification of patients presenting with gastrointestinal bleeding; frequently, however, it is not immediately available. Initial management and triage of patients thus depends on nonendoscopic information. We sought to risk stratify patients with upper gastrointestinal bleeding using variables available on initial presentation (ie., before endoscopy).

METHODS

A retrospective observational study was performed using data from 335 admissions with an initial diagnosis of upper gastrointestinal hemorrhage. All patients underwent endoscopy and were evaluated for an adverse outcome during their hospitalization. An adverse outcome was defined as death, the need for any operation, recurrent hematemesis, recurrent melena after initial clearing, or a hematocrit falling despite transfusion.

RESULTS

Univariate analysis identified 17 distinct variables associated (p < 0.05) with an adverse outcome. A stepwise logistic regression identified five variables as independent predictors (p < 0.05) of an adverse outcome: an initial hematocrit <30%, initial systolic blood pressure < 100 mm Hg, red blood in the nasogastric lavage, history of cirrhosis or ascites on exam, and a history of vomiting red blood. We derived a decision rule based on patients having 0-5 of these independent predictors. This decision rule allowed identification of a large patient population with a <10% chance of an adverse outcome.

CONCLUSION

Risk stratification is possible from information available at the time of initial presentation. If confirmed in other populations, these predictors can be used to identify patients who require a less intensive level of care.

Alterations in baseline activity and quinpirole sensitivity in putative dopamine neurons in the substantia nigra and ventral tegmental area after withdrawal from cocaine pretreatment

Using in vivo single-unit recording, we compared in rats the-effects of continuous infusion and once-a-day injections of cocaine on the activity of single putative dopamine neurons in the substantia nigra and ventral tegmental area. After a 7-day withdrawal, we determined: (1) the number of spontaneously active neurons and their bursting patterns and (2) sensitivity of these neurons to intravenous quinpirole. In the substantia nigra, continuous cocaine infusion reduced the number of neurons without affecting the bursting patterns; daily injections were without effects. In the ventral tegmental area, continuous infusion reduced the bursting activity without affecting the number of neurons, whereas injections increased number of neurons without changes in the bursting pattern. Acute sulpiride normalized all the changes in both cell body areas. The quinpirole sensitivity was selectively increased in the nigral neurons following withdrawal from continuous infusion. Possible role of D2/autoreceptor mechanisms in these changes is discussed.