Radiological control for 203Hg radiotracer determinations of mercury inventories at chlor-alkali plants

20Hg has been used safely to determine mercury inventories in large electrochemical process cells in the chlorine industry by a process of isotopic dilution. Laboratory conversion and processing of irradiated HgO can be done in closed systems with non-detectable releases to work areas or the environment and with exposure to whole body <0.25 mSv (25 mrem) and <3 mSv (300 mrem) to extremities. Personnel exposures during plant operations are controlled to non-detectable levels for whole body exposure and <0.3 mSv (30 mrem) to extremities for the operator; exposures for other plant personnel are non-detectable.

Amniotic membrane used for vulvar adhesion treatment

We report here a case of vulvar adhesion that was difficult to cure by estrogen only. We used amniotic membrane to be a barrier and after the operation, the symptoms of vulvar adhesion were resolved.

Pro-survival function of Akt/protein kinase B in prostate cancer cells. Relationship with TRAIL resistance

Tumor necrosis factor superfamily member TRAIL/Apo-2L has recently been shown to induce apoptosis in transformed and cancer cells. Some prostate cancer cells express constitutively active Akt/protein kinase B due to a complete loss of lipid phosphatase PTEN gene, a negative regulator of phosphatidylinositol 3-kinase pathway. Constitutively active Akt promotes cellular survival and resistance to chemotherapy and radiation. We have recently noticed that some human prostate cancer cells are resistant to TRAIL. We therefore examined the intracellular mechanisms of cellular resistance to TRAIL. The cell lines expressing the highest level of constitutively active Akt were more resistant to undergo apoptosis by TRAIL than those expressing the lowest level. Down-regulation of constitutively active Akt by phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, reversed cellular resistance to TRAIL. Treatment of resistant cells with cycloheximide (a protein synthesis inhibitor) rendered cells sensitive to TRAIL. Transfecting dominant negative Akt decreased Akt activity and increased TRAIL-induced apoptosis in cells with high Akt activity. Conversely, transfecting constitutively active Akt into cells with low Akt activity increased Akt activity and attenuated TRAIL-induced apoptosis. Inhibition of TRAIL sensitivity occurs at the level of BID cleavage, as caspase-8 activity was not affected. Enforced expression of anti-apoptotic protein Bcl-2 or Bcl-X(L) inhibited TRAIL-induced mitochondrial dysfunction and apoptosis. We therefore identify Akt as a constitutively active kinase that promotes survival of prostate cancer cells and demonstrate that modulation of Akt activity, by pharmacological or genetic approaches, alters the cellular responsiveness to TRAIL. Thus, TRAIL in combination with agents that down-regulate Akt activity can be used to treat prostate cancer.

Inner ear localization of mRNA and protein products of COCH, mutated in the sensorineural deafness and vestibular disorder, DFNA9

Missense mutations in the COCH gene, which is expressed preferentially at high levels in the inner ear, cause the autosomal dominant sensorineural deafness and vestibular disorder, DFNA9 (OMIM 601369). By in situ hybridization of mouse and human inner ear sections, we find high-level expression of COCH mRNA in the fibrocytes of the spiral limbus and of the spiral ligament in the cochlea, and in the fibrocytes of the connective tissue stroma underlying the sensory epithelium of the crista ampullaris of the semicircular canals. A polyclonal antibody against the human COCH protein product, cochlin, was raised against the N-terminal 135 amino acid residues of cochlin, corresponding to the Limulus factor C-homology (cochFCH) domain; this domain harbors all five known point mutations in DFNA9. On western blots of human fetal cochlear extracts, anti-cochlin reacts with a cochlin band of the predicted full-length size as well as a smaller isoform. Immunohistochemistry performed with anti-cochlin shows staining predominantly in the regions of the fibrocytes of the spiral limbus and of the spiral ligament in mouse and in human fetal and adult tissue sections. These sites correspond to those areas that express COCH mRNA as determined by in situ hybridization, and to the regions of the inner ear which show histological abnormalities in DFNA9. The fibrocytes expressing mRNA and protein products of COCH are the very cell types which are either absent or markedly reduced and replaced by eosinophilic acellular material in temporal bone sections of individuals affected with DFNA9.

Automated nasopharyngeal carcinoma detection with dynamic gadolinium-enhanced MR imaging

OBJECTIVES

The purpose of this research is to develop an automatic medical diagnosis for segmenting nasopharyngeal carcinoma (NPC) with dynamic gadolinium-enhanced MR imaging.

METHODS

This system is a multistage process, involving motion correction, head mask generation, dynamic MR data quantitative evaluation, rough segmentation, and rough segmentation refinement. Two approaches, a relative signal increase method and a slope method, are proposed for the quantitative evaluation of dynamic MR data.

RESULTS

The NPC detection results obtained using the proposed methods had a rating of 85% in match percent compared with these lesions identified by an experienced radiologist. The match percent for the two proposed methods did not have significant differences. However, the computation cost for the slope method was about twelve times faster than the relative signal increase method.

CONCLUSIONS

The proposed methods can identify the NPC regions quickly and effectively. This system can enhance the performance of clinical diagnosis.

Bone mineral density in young female Chinese dancers

To evaluate of the effect of dancing on bone mineral density (BMD) we compared 29 Chinese girls who had been receiving regular ballet training for at least 6 years with a control group of 20 nonathletic sex- and age-matched Chinese girls. BMD was measured at the second to fourth lumbar spine and at the right femoral neck using a commercial dual-energy X-ray absorptiometer (DEXA). There were no significant differences in either measured BMD or spinal BMD after adjusting for body weight (body mass index). Adjusted BMD of the femoral neck, however, showed significant differences (P <0.05). Results revealed that the ballet dancers were significantly thinner than the control group and the negative effect of a lower bodyweight may neutralize the positive effect of ballet dancing on BMD, especially in the femoral neck.

Identification of antibodies to heat shock proteins 90 kDa and 70 kDa in patients with schizophrenia

OBJECTIVES

Recent reports of antibodies to heat shock proteins 60kDa (HSP60) and HSP70 suggested that antibodies to the heat shock protein that plays a protective role against environmental stresses in a cell might be related to the pathogenesis of schizophrenia, although the antibody to HSP90 had not yet been identified in patients with schizophrenia. In this study, we tried to elucidate the specific involvement of the autoimmunity to HSPs in the pathogenesis and development of schizophrenia.

METHODS

Antibodies to HSP90 and HSP70 in 90 patients with schizophrenia and in 83 normal controls were measured by enzyme-linked immunosorbent assay (ELISA) coupled with the avidin-biotin system. In the patients, the association between antibody levels and clinical variables were sought. In addition, changes in antibody levels after treatment with antipsychotic medication were investigated.

RESULTS

Eighteen (20.0%) of the 90 patients showed 'high' levels of antibody to HSP90 above a cutoff value, and 28 (31.1%) of those showed 'high' antibody levels to HSP70. On the other hand, only four (4.8%) of the normal controls showed 'high' HSP90 antibody levels, and one (1.2%) of these showed 'high' antibody level to HSP70. The distribution of elevated HSP90 antibody was significantly associated with that of elevated HSP70 antibody in the patients with schizophrenia. The patients with 'high' levels of antibody to HSP70 showed higher initial Brief Psychiatric Rating Scale (BPRS) scores and showed greater clinical improvement than those with 'low' levels, while the patients with 'high' levels of antibody to HSP90 did not. The frequency of patients with high levels of antibody to HSP70 was decreased significantly after 6 weeks of antipsychotic treatment, while the frequency of patients with high levels of antibody to HSP90 was not.

CONCLUSIONS

Our results presented the presence of abnormal immune reactivity involving antibody to HSP90 and antibody to HSP70 in a subset of patients with schizophrenia. Differential patterns of distribution, of the association with clinical symptom severity, and of the changes of levels with treatment suggested the possibility that these two antibodies might be involved specifically in the pathogenesis of schizophrenia.

Developing and deploying a patient safety program in a large health care delivery system: you can't fix what you don't know about

BACKGROUND

The Veterans Administration (VA) identified patient safety as a high-priority issue in 1997 and implemented the Patient Safety Improvement (PSI) initiative throughout its entire health care system. In spring 1998 the External Panel on Patient Safety System Design recommended alternative methods to enhance reporting and thereby improve patient safety. REDESIGNING THE PSI INITIATIVE: The VA began redesigning the PSI initiative in late 1998. The dedicated National Center for Patient Safety (NCPS) was established. Using the panel's recommendations as a jumping-off point, NCPS began to identify known and suspected obstacles to implementation (such as possible punitive consequences and additional workload). NCPS adopted a prioritization scoring method, the Safety Assessment Code (SAC) Matrix, for close calls and adverse events, which requires assessing the event's actual or potential severity and the probability of occurrence. The SAC Matrix specifies actions that must be taken for given scores. Use of the SAC score permits a consistent handling of reports throughout the VA system and a rational selection of cases to be considered. A system for performing a root cause analysis (RCA) was developed to guide caregivers at the frontline. This system includes a computer-aided tool, a flipbook containing a series of six questions, and reporting of the findings back to the reporter. The final step requires that the facility's chief executive officer "concur" or "nonconcur" on each recommended corrective action. The RCA team outlines how the effectiveness of the corrective action will be evaluated to verify that the action has had the intended effect, and it ascertains that there were no unintended negative consequences.

IMPLEMENTATION

Based on successful implementation in two pilots, full-scale national rollout to the 173 facilities began in April 2000 and was concluded by the end of August 2000. NCPS supplied 3 days of training for individuals at each facility. The training included didactic components, an introduction to human factors engineering concepts, and small- and large-group simulation exercises. Facility leaders were reminded of the necessity to reinforce the point that assignment to an RCA team was considered an important duty.

DISCUSSION

It is essential to design and implement a system that takes into account the concerns of the frontline personnel and is aimed at being a tool for learning and not accountability. The system must have as its primary focus the dissemination of positive actions that reduce or eliminate vulnerabilities that have been identified, not a counting exercise of the number of reports.

Role of the connectivity of secondary structure segments in the folding of alpha(1)-antitrypsin

The native form of serpins (serine protease inhibitors) is metastable, which is critical to their biological functions. Spontaneous conversion from the native form of serpins into a more stable conformation, called the "latent" form, is restricted. To examine whether the connectivity of strand 1 of beta-sheet C to the hydrophobic core is critical to the serpin's preferential folding to the metastable native conformation, we designed a circularly-permuted mutant of alpha(1)-antitrypsin, the prototype serpin, in which strand 1C is disconnected from the hydrophobic core. Conformation of the circular permutant was similar to that of the latent form, as revealed by equilibrium unfolding, limited proteolysis, and spectroscopic properties. Our results support the notion that rapid folding of the hydrophobic core with concomitant incorporation of strand 1C into beta-sheet C traps the serpin molecule into its native metastable conformation.

The first 1,3-digermyla-2-nickela-carboranylene and the Ni-catalyzed double germylation of unsaturated organic substrates

The reaction of o-bis(dimethylgermyl)carborane with Ni(PEt3)4 in pentane affords the reactive intermediate, [o-(GeMe2)2C2B10H10]Ni(PEt3)2 2: the facile double germylation of unsaturated organic substrates catalyzed by 2 is reported.

Constitutively active Akt is an important regulator of TRAIL sensitivity in prostate cancer

TRAIL/Apo-2L is a member of the tumor necrosis factor superfamily and has recently been shown to induce apoptosis in cancer cells, but not in normal cells. In nude mice injected with human tumors, TRAIL reduces the size of these tumors without side effects. Akt promotes cell survival and block apoptosis. Some prostate cancer cells express high levels of Akt due to lack of active lipid phosphatase PTEN, a negative regulator of PI-3 kinase pathway, which may be responsible for drug resistance. The objective of this paper is to investigate the intracellular molecules that regulate TRAIL resistance. We have examined caspase-8 activity, BID cleavage, Akt activity, mitochondrial membrane potential (DeltaPsi(m)) and apoptosis in prostate cancer (LNCap, PC-3, PC-3M and DU145) cells treated with or without TRAIL. PC-3, PC-3M and DU145 cells are sensitive to TRAIL, whereas LNCap cells are resistant. LNCap cells express the highest level of constitutively active Akt, which is directly correlated with TRAIL resistance. TRAIL activates caspase-8 in all the cell lines. Downregulation of constitutively active Akt by PI-3 kinase inhibitors (wortmannin and LY-294002), dominant negative Akt or PTEN, renders LNCap cells sensitive to TRAIL. Inhibition of TRAIL sensitivity occurs at the level of BID cleavage. Inhibition of protein synthesis by cycloheximide also causes LNCap cells sensitive to TRAIL. Overexpression of Bcl-2 or Bcl-X(L) inhibits TRAIL-induced DeltaPsi(m) and apoptosis. Overexpression of constitutively active Akt in PC-3M cells (express very low levels of constitutively active Akt) restores TRAIL resistance. These data suggest that elevated Akt activity protects LNCap cells from TRAIL-induced apoptosis, and the PI-3 kinase/Akt pathway may inhibit apoptotic signals by inhibiting processing of BID. Thus, constitutively active Akt is an important regulator of TRAIL sensitivity in prostate cancer.

Off-pump coronary artery bypass may decrease the patency of saphenous vein grafts

BACKGROUND

There is concern that a hypercoagulable status is caused after coronary artery bypass grafting without cardiopulmonary bypass (off-pump coronary artery bypass grafting, or OPCAB) and may potentially endanger the patency of the anastomosis. The aims of this study were: (1) to compare 1-year graft patency after OPCAB with that of conventional coronary artery bypass grafting (CABG) and that of on-pump beating CABG; and (2) to demonstrate any differences in patency of various conduits among the three groups.

METHODS

We analyzed the results of 122 consecutive OPCAB cases (group 1) compared with those of 65 consecutive conventional CABG cases (group II) and those of 19 consecutive on-pump beating CABG cases (group III). In group I, coronary angiography (CAG) was performed immediately postoperatively and 1 year after surgery. In groups II and III, CAG was performed 1 year after surgery. Graft patency was graded as grade A (excellent), grade B (fair), or grade O (occluded).

RESULTS

The average number of distal anastomoses in groups I, II, and III were 3.1 +/- 1.1, 3.7 +/- 0.9, and 3.6 +/- 0.9, respectively. In group I, postoperative CAG was performed in 92% of patients (112/122) before discharge. The patency rate (grade A + B) was 96.4% (162/168) for arterial grafts, and 85.6% (160/187) for saphenous vein grafts (SVG). One-year follow-up CAG was performed in 74% of patients (90/122). The patency rate was 97.8% (132/135) for arterial grafts and 67.9% (106/156) for SVG. In group II, 1-year follow-up CAG was performed in 65% of patients (42/65). The patency rate (grade A + B) was 93.5% (43/46) for arterial grafts and 88.3% (98/111) for SVG. In group III, 1-year follow-up CAG was performed in 89% of patients (17/19). The patency rate (grade A + B) was 100% (19/19) for arterial grafts and 86.8% (33/38) for SVG.

CONCLUSIONS

Our results demonstrate that the patency rate ot SVG after OPCAB was significantly lower than that of arterial grafts in the early postoperative CAG (p < 0.001), and was also significantly lower than those of SVG of group II (p < 0.001) and group III (p < 0.01) in the postoperative 1-year CAG, although there was no significant difference in 1-year patency of arterial grafts among the three groups. Our data suggest that a specific perioperative anticoagulant therapy may be advisable in patients undergoing OPCAB with SVG.

Minimization of MC1R selectivity by modification of the core structure of alpha-MSH-ND

BACKGROUND

Melanocortin, through its distinct receptor subtypes, has many different effects. Receptor-selective ligands are required to reduce the undesirable effects of melanocortin. To investigate which conformation is preferable to a given melanocortin receptor subtype, a structural and functional analysis of the ligand-receptor interactions was made by studying the biological activity, the nuclear magnetic resonance structures, and the patterns of the ligand-receptor interaction for each receptor subtype by homology modeling analysis.

RESULTS

Among the several analogues examined, [Gln(6)]alpha-melanocyte-stimulating hormone (MSH)-ND was found to have 10000 times less biological activity than alpha-MSH-ND for the MC1R, whereas, the potencies of both oligopeptides were comparable in both the melanocortin-3 receptor (MC3R) and MC4R. [Gln(6)]alpha-MSH-ND exhibited a type I' beta-turn that was similar to the type I beta-turn structure of alpha-MSH-ND. However, a remarkable structural difference was observed with respect to the side chain orientations of the sixth and seventh residues of [Gln(6)]alpha-MSH-ND, which were found to be mirror images of alpha-MSH-ND. By homology modeling analysis, the His(6) of alpha-MSH-ND was found to interact with the TM2 regions of all three receptors (Glu(94) of MC1R, Glu(94) of MC3R, and Glu(100) of MC4R), but [Gln(6)]alpha-MSH-ND did not. The phenyl ring of the D-Phe(7) residue of [Gln(6)]alpha-MSH-ND revealed an interaction with the TM3 regions of both the MC3R and MC4R (Ser(122) of MC3R or Ser(127) of MC4R). However, in the MC1R, these serine residues corresponded to Val(122), which contains two methyl groups that induce steric hindrance with D-Phe(7) of [Gln(6)]alpha-MSH-ND. This is a possible explanation for the biological activity of [Gln(6)]alpha-MSH-ND for the MC1R being significantly lower than that for either the MC3R or MC4R.

CONCLUSIONS

Minimization of the MC1R selectivity whilst preserving its comparable potency for both the MC3R and MC4R could be achieved by modifying the D-Phe(7) orientation of alpha-MSH-ND, while maintaining the 'type I beta-turn'-like structure.

Detection of inducible nitric oxide synthase- and nitrotyrosine-positive cells in the lesions of pericarditis induced by porcine enterovirus serotype 3 infection

The expression of inducible nitric oxide synthase (iNOS), an enzyme that produces nitric oxide, was examined in the hearts of pigs infected with porcine enterovirus serotype 3 (PEV3). Piglets orally infected with PEV3 developed tremors and paralysis 3-7 days post-infection. Affected animals had pericarditis and myocarditis. There were fibrin and inflammatory cell infiltrates (macrophages and neutrophils) in the pericardial sac and myocardium. Immunohistochemically, the majority of inflammatory cells in the pericardial sac were positive for iNOS and nitrotyrosine, an end product of nitric oxide. These results suggest that iNOS is upregulated in the pericardial lesion, and that increased nitric oxide production plays an important role in the development of PEV3-induced pericarditis and myocarditis.

Inhibition of myocardial apoptosis as a therapeutic target in cardiovascular disease prevention: focus on caspase inhibition

Apoptosis is a type of programmed cell death that is evident during embryonic development and normal tissue turnover. When the apoptotic activity extends beyond physiologic limits, it can determine and/or contribute to those pathologic states characterized by excessive cell loss and impairment of organ function. The clinical development of caspase inhibitors may represent a potential therapeutic strategy for influencing the onset and progression of ventricular dysfunction to terminal failure. This article focuses on the caspase cascade, a fundamental enzymatic system for apoptotic cell death. Caspases do not constitute the death signals, but are implicated in their transmission. These cytoplasmic cysteine proteases have a dual role in apoptosis. Caspases can operate as initiators, activating an endonuclease that catalyzes deoxyribonucleic acid fragmentation. Alternatively, caspases can act as effectors, participating in the total disassembly of cell structures. For example, apoptosis represents the principal form of myocyte death in the region of an acute myocardial infarction. In addition, apoptosis in the region bordering the infarct can influence the development of ischemic cardiomyopathy and ventricular dilation.

Robust image registration for functional magnetic resonance imaging of the brain

Motion-related artifacts are still a major problem in data analysis of functional magnetic resonance imaging (FMRI) studies of brain activation. However, the traditional image registration algorithm is prone to inaccuracy when there are residual variations owing to counting statistics, partial volume effects or biological variation. In particular, susceptibility artifacts usually result in remarkable signal intensity variance, and they can mislead the estimation of motion parameters. In this study, Two robust estimation algorithms for the registration of FMRI images are described. The first estimation algorithm was based on the Newton method and used Tukey's biweight objective function. The second estimation algorithm was based on the Levenberg-Marquardt technique and used a skipped mean objective function. The robust M-estimators can suppress the effects of the outliers by scaling down their error magnitudes or completely rejecting outliers using a weighting function. The proposed registration methods consisted of the following steps: fast segmentation of the brain region from noisy background as a preprocessing step; pre-registration of the volume centroids to provide a good initial estimation; and two robust estimation algorithms and a voxel sampling technique to find the affine transformation parameters. The accuracy of the algorithms was within 0.5 mm in translation and within 0.5 degrees in rotation. For the FMRI data sets, the performance of the algorithms was visually compared with the AIR 2.0 software, which is a software for image registration, using colour-coded statistical mapping by the Kolmogorov-Smirov method. Experimental results showed, that the algorithms provided significant improvement in correcting motion-related artifacts and can enhance the detection of real brain activation.

Pyridopyrimidine analogues as novel adenosine kinase inhibitors

A novel series of pyridopyrimidine analogues 9 was identified as potent adenosine kinase inhibitors based on the SAR and computational studies. Substitution of the C7 position of the pyridopyrimidino core with C2' substituted pyridino moiety increased the in vivo potency and enhanced oral bioavailability of these adenosine kinase inhibitors.

The role of tissue transglutaminase in the germinal vesicle breakdown of mouse oocytes

We have investigated the novel function of tissue transglutaminase (tTG) in the germinal vesicle breakdown (GVBD) of mouse oocyte. tTG was identified in ooplasm and germinal vesicle by immunostaining with less amount in germinal vesicle. Spontaneous maturation of the oocytes elevated in situ activity of tTG by over 2.5-fold at 3 h, which was determined by a confocal microscopic assay. However, incubation with monodansylcadaverine (MDC), a tTG inhibitor, blocked the activation of tTG. The possible role of tTG in GVBD was investigated by the use of two tTG inhibitors, MDC and cystamine. MDC largely inhibited the GVBD by a concentration-dependent manner. GV-stage oocytes were matured to the GVBD stage by 78% at 3 h in the normal culture condition. However, in the oocytes incubated with MDC for 3 h, the GVBD rates were 43 and 11% by 50 and 100 microM, respectively. MDC also blocked the entry of 70 kDa RITC-dextran from the ooplasm to the compartment of germinal vesicle, indicating a possible inhibition of nuclear pore disassembly by MDC. The role of tTG in GVBD was further investigated by microinjection with cystamine. The control oocytes, injected with DPBS, showed about 80% of GVBD at 3 h. But the oocytes injected with cystamine showed 15% of GVBD at 3 h and a little higher rate at 6 h. In addition, the inhibition of GVBD maturation by MDC was reversible by washing. These results suggested that tTG was involved in the early event of mouse oocyte maturation.

Phase transitions and critical phenomena in the liquid bridge under lateral acceleration

We study the shape of a liquid body under the influence of a lateral body force in a thin liquid bridge. The shape of the liquid body changes continuously or discontinuously depending on the volume of liquid body. We show that the transition from discontinuous to continuous change is described by the volume-induced phase transition driven by the lateral body force. The order parameter of the phase transition is the amount of shift of the center of mass of liquid body. Critical exponents of a mean-field model have been obtained by numerical calculation. We provide the validity of this critical behavior through the m(4) model of Landau theory of phase transition.

Extremely low doses of tissue factor pathway inhibitor decrease mortality in a rabbit model of septic shock

OBJECTIVE

We sought to determine the lowest dose of recombinant human tissue factor pathway inhibitor (TFPI) that can provide protection from lethality in a rabbit model of septic shock.

METHODS

Sepsis was induced in New Zealand white rabbits by intraperitoneal implantation of 7.0 ml of a solution containing hemoglobin (4.8 g/dl), porcine mucin (6 g/dl), and 0.8-1.4 x 10(4) viable Escherichia coli (strain O:18 K+). Gentamicin (5 mg/kg) was administered 4 h following surgery, and this dose was repeated every 12 h for 3 days. Beginning 4 h following the induction of sepsis, animals were treated with a bolus (1 ml) plus a continuous infusion (100 ml over 24) of either TFPI (various doses) or its vehicle. Four different doses of TFPI were studied, and each experiment included a contemporaneous control group. The primary outcome parameter was survival time. Results were analyzed using the Wilcoxen log rank test.

RESULTS

The average survival time for rabbits treated with the highest dose of TFPI tested (50 microg/kg bolus and 0.5 microg/kg per minute infusion) was 118 h, as compared to 81 h in vehicle-treated controls). The average survival time for septic rabbits treated with a much lower dose of TFPI (100 ng/kg bolus and 1.0 ng/kg per minute infusion) was 119 h as compared to 57 h in surviving vehicle-treated controls. Treatment with an even lower dose of TFPI (10 ng/kg bolus and 0.1 ng/kg per minute infusion) still produced a marginally significant prolongation of average survival time (80 h) relative to contemporaneously studied controls (47 h). When the dose of TFPI was decreased still further (1.0 ng/kg bolus and 0.01 ng/kg per minute infusion), average survival times were not significantly different between TFPI-treated and vehicle-treated rabbits (77 and 51 h, respectively).

CONCLUSIONS

Delayed infusion with remarkably low doses of recombinant human TFPI prolongs survival in a rabbit model of antibiotic-treated Gram-negative bacterial sepsis. In planning human trials of TFPI as an adjuvant treatment for sepsis it may be reasonable to use much lower doses of the agent than were heretofore contemplated.

Genomic structure, functional comparison, and tissue distribution of mouse Cd59a and Cd59b

CD59 is a crucial complement regulatory protein that inhibits the terminal step of the complement activation cascade by interfering with the binding of C9 to C5b-8, thus preventing the formation of the membrane attack complex (MAC). We recently reported that the mouse genome contains two Cd59 genes, while the human and rat genomes each contain only one Cd59 gene (Qian et al. 2000). Here, we describe the genomic structure, comparative activity, and tissue distribution of these two mouse genes, designated Cd59a and Cd59b. The mouse Cd59 genes encompass a total of 45.6 kb with each gene having four exons. Cd59a spans 19 kb, and Cd59b spans 15 kb, with approximately 11.6 kb of genomic DNA separating the two genes. The overall sequence similarity between Cd59a and Cd59b is approximately 60%. The sequence similarity between exon 2, exon 3, and exon 4 and the respective flanking regions between the two genes is over 85%, but exon 1 and its flanking regions are totally different. Comparative studies of the activity of both genes as inhibitors of MAC formation revealed that Cd59b has a specific activity that is six times higher than that of Cd59a. Using polyclonal antibodies specific to either Cd59a or Cd59b, we showed that Cd59a and Cd59b are both widely expressed in the kidneys, brain, lungs, spleen, and testis, as well as in the blood vessels of most mouse tissues. Interestingly, testicular Cd59a appeared to be expressed exclusively in spermatids, whereas Cd59b was expressed in more mature sperm cells. These results suggest that even though Cd59a and Cd59b are expressed in multiple tissues, they may play some different roles, particularly in reproduction.