Survival benefit of a third dose of the COVID-19 vaccine among hemodialysis patients: A prospective cohort study

BACKGROUND

Hemodialysis (HD) patients are particularly vulnerable to severe coronavirus disease 2019 (COVID-19) due to their immunocompromised state and comorbid conditions. Timely vaccination could be the most effective strategy to reduce morbidity and mortality. However, data on the survival benefit of the COVID-19 vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and death among HD patients are limited, especially during the Omicron-dominant period.

METHODS

In this prospective hospital-based cohort study, we identified HD patients from July 1, 2021, to April 29, 2022. The patients were divided into fully vaccinated and partially vaccinated groups. We compared the humoral response, risk of developing SARS-CoV-2 infection, and all-cause mortality between the two groups.

RESULTS

Among the 440 HD patients included, 152 patients were fully vaccinated, and 288 patients were partially vaccinated. Patients in the fully vaccinated group exhibited higher anti-spike protein receptor-binding domain (S protein RBD) antibody levels and lower risks of all-cause mortality (adjusted hazard ratio, 0.35; 95% confidence interval, 0.17-0.73; p = 0.005) than the partially vaccinated group. However, the risk for SARS-CoV-2 infection did not significantly differ between the two groups. Irrespective of the number of vaccinations, the risk of all-cause mortality was lower in patients with anti-S protein RBD antibody levels in the higher tertile.

CONCLUSION

A third dose of the COVID-19 vaccine was associated with a decreased risk of all-cause mortality among HD patients during the Omicron-dominant period. A higher post-vaccination anti-S protein RBD antibody level was also associated with a lower risk of mortality.

Leukocyte 8-hydroxy-2'-deoxyguanosine as an oxidative stress marker to predict cardiovascular events and death in chronic hemodialysis patients

BACKGROUND

Hemodialysis patients have a markedly increased risk of cardiovascular (CV) morbidity and mortality. Oxidative stress plays a pathogenic role in the progression of atherosclerosis and CV disease among chronic hemodialysis patients. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) content in leukocyte deoxyribonucleic acid (DNA) has been shown as a sensitive and well-known biomarker of oxidant-induced DNA damage in chronic hemodialysis patients.

METHODS

We conducted a retrospective cohort study to investigate the association of leukocyte 8-OHdG and CV events and deaths in patients of chronic hemodialysis. In this study, 217 chronic hemodialysis patients were recruited from 2016 to 2021. The 8-OHdG content of leukocyte DNA was measured by a high-performance liquid chromatography electrochemical detection method. Study outcomes were CV events as well as CV and all-cause deaths. The patients were followed until May 2021.

RESULTS

The median follow-up period was 34.8 months. At the end of May 2021, 57 first CV events and 89 all-CV events occurred. Among the first and all CV events, 17 (29.8%) and 32 (36.0%) were fatal, respectively. Multivariate Cox regression analysis showed per 1/10 5 dG increment in leukocyte 8-OHdG values increased risk of CV events (adjusted hazard ratio [aHR], 1.19; 95% CI, 1.10-1.41; p < 0.001), CV death (aHR, 1.27; 95% CI, 1.03-1.72; p = 0.034), and all-cause death (aHR, 1.11; 95% CI, 1.01-1.30; p = 0.038).

CONCLUSION

This is the first study to demonstrate that oxidative stress assessed by 8-OHdG levels of leukocyte DNA predicted CV events as well as CV and all-cause deaths among chronic hemodialysis patients.

The Associations between Erythropoietic Response with Inflammation Markers and Perfluorinated Chemicals in Hemodialysis Patients

Erythropoiesis-stimulating agents (ESA) are used to treat anemia in hemodialysis (HD) patients. We investigated the role of inflammation and accumulation of environmental toxins (perfluorinated chemicals (PFCs), such as perfluorooctanoic acid and perfluorooctane sulfonate) in the erythropoietic response of HD patients who receive a fixed monthly continuous erythropoietin receptor activator (CERA) dosage. Forty-five patients underwent three successive phases of ESA treatment for two months each (phase one: 100 µg CERA once monthly; phase two: 50 µg CERA twice monthly; phase three: 100 µg CERA once monthly). Patient data were collected to determine the association of various factors with erythropoietic response (change in hematocrit). Liquid chromatography-tandem mass spectrometry was used to analyze perfluorinated chemicals. Twenty-eight patients exhibited a poor erythropoietic response that was significantly associated with: age > 80 years, initial hematocrit > 36%, glucose > 200 mg/dL, alanine aminotransferase > 21 U/L, c-reactive protein > 1 mg/dL, interleukin-6 > 10 ng/mL, lactate dehydrogenase ≤ 190 U/L, and chloride ≤ 93 mEq/L. There was also a borderline significant association between inflammation and PFCs, although PFCs failed to show any impact on ESA response. Age, glucose, chloride, liver function, and inflammation may be associated with cost-effective fixed CERA dosage administered at an increased frequency.

Bilirubin Links HO-1 and UGT1A1*28 Gene Polymorphisms to Predict Cardiovascular Outcome in Patients Receiving Maintenance Hemodialysis

Serum bilirubin levels, which are determined by a complex interplay of various enzymes, including heme oxygenase-1 (HO-1) and uridine diphosphate–glucuronosyl transferase (UGT1A1), may be protective against progression of cardiovascular disease (CVD) in hemodialysis patients. However, the combined effect of HO-1 and UGT1A1*28 gene polymorphisms on CVD outcomes among hemodialysis patients is still unknown. This retrospective study enrolled 1080 prevalent hemodialysis patients and the combined genetic polymorphisms of HO-1 and UGT1A1 on serum bilirubin were analyzed. Endpoints were CVD events and all-cause mortality. Mean serum bilirubin was highest in patients with S/S + S/L of the HO-1 promoter and UGT1A1 7/7 genotypes (Group 1), intermediate in those with S/S + S/L of the HO-1 promoter and UGT1A1 7/6 + 6/6 genotypes (Group 2), and lowest in the carriers with the L/L HO-1 promoter and UGT1A1 7/6 + 6/6 genotypes (Group 3) (p < 0.001). During a median follow-up of 50 months, 433 patients developed CVD. Compared with patients in Group 3, individuals among Groups 1 and 2 had significantly lower risks for CVD events (adjusted hazard ratios (aHRs) of 0.35 for Group 1 and 0.63 for Group 2), respectively. Compared with the lower bilirubin tertile, the aHRs were 0.72 for the middle tertile and 0.40 for the upper tertile for CVD events. We summarized that serum bilirubin as well as HO-1 and UGT1A1 gene polymorphisms were associated with CVD among patients receiving chronic hemodialysis.

Iron Therapy in Chronic Kidney Disease: Days of Future Past

Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.

IgM mesangial deposition as a risk factor for relapses of adult-onset minimal change disease

BACKGROUND

Immunoglobulin M (IgM) mesangial deposition in pediatric minimal change disease (MCD) has been reported to be associated with steroid dependence and poor renal outcomes. However, the evidence linking the impacts of IgM mesangial deposition to the treatment prognosis in adult-onset MCD is still elusive.

METHODS

In this retrospective cohort study, 37 adult patients with MCD received kidney biopsies from January 2010 to May 2020. Immunofluorescence microscopy was performed and the patients dichotomized according to IgM mesangial deposition (12 patients with positive IgM deposition; 25 patients with negative IgM deposition). We analyzed the clinical features, the dosage of immunosuppressive agents, and the response to treatment for 2 years between the two groups.

RESULTS

Analysis of the clinical symptoms, the dosage of immunosuppressive treatment, and the time to remission revealed no statistical difference between the groups. However, compared to the negative IgM group, the frequency of relapses was significantly higher in the positive IgM group during the two-year follow-up period (the negative IgM group 0.25 episodes/year; the positive IgM group 0.75 episodes/year, p = 0.029). Furthermore, multivariate linear regression revealed that the positivity of IgM mesangial deposition is independently associated with the frequency of relapses (regression coefficient B 0.450, 95% CI 0.116-0.784, p = 0.010).

CONCLUSIONS

Our findings indicated that adult-onset MCD patients with IgM mesangial deposition have a high risk of relapses. Therefore, intensive monitoring of disease activity should be considered in MCD adults with IgM mesangial deposition.

Correction to: A Nautilus kidney

In the original publication of the article, the second sentence under the heading, Case presentation appears incorrectly as A computed tomographic (CT) scan demonstrated left-sided hydronephrosis (Fig. 1).

Hemodialysis vascular access care during the COVID-19 pandemic

Dialysis patients are more vulnerable and susceptible to the severe coronavirus disease 2019 (COVID-19) infection due to multiple comorbidities. Since Taiwan has the highest incidence and prevalence of treated end-stage kidney disease worldwide, it is crucial to act in advance to prevent a potential disaster. In the face of the COVID-19 pandemic, we implement proactive infection control measures to prevent it from spreading without sacrificing the dialysis care quality. In this article, we focused on hemodialysis vascular access (HVA) care in particular. As a life-line of hemodialysis (HD) patients, HVA care has a profound impact on the patient's quality of dialysis and life. Specifically, in our facility, the working and office areas of the HD units are separated to reduce cross-infection. All elective procedures for HVA are postponed, and operating rooms equipped with a negative-pressure anteroom are used for the suspected or confirmed COVID-19 patients. Herein, we share how we modified our HVA care policy not only to prevent our patients from COVID-19 infection but also to maintain the quality of HVA care.

A Nautilus kidney

We report a 71-year-old woman who presented with unilateral flank pain and sepsis. A computed tomographic (CT) scan demonstrated left-sided hydronephrosis. Subsequent percutaneous nephrotomy drainage showed pus-like material, confirming the diagnosis of pyonephrosis. The ureteral stricture was caused by previous radiation injury for cervical cancer in this ESRD patient who was on chronic dialysis for years. In our case, the grade IVB hydronephrosis is a result of an extremely atrophic kidney, pyonephrosis, and ureteral stricture. The CT section of pyonephrosis in an extremely atrophic kidney resembles a sagittal section of a Nautilus shell, as the shell corresponds to the diffusely thinned renal cortex.

IL-2 withdrawal from human CD8+ T cell expansion in the presence of IL-7 enables retention of favorable functional and phenotypic characteristics for adoptive immunotherapy (165.2)

Viral infection and reactivation of latent viruses are major causes of mortality and morbidity following haematopoietic stem cell transplantation. Adoptive immunotherapy with CD8+ T cells has proven efficacy in preventing or treating post-transplant viral infection, including therapy with resting T cells that undergo homeostatic expansion in vivo that follows transplantation. However T cells continuously expanded in vitro in IL-2 lose many characteristics associated with efficacy in vivo, and most IL-2-expanded cells die soon after infusion. Here we describe an alternative expansion protocol for human CD8+ T cells that only exposes the cells briefly to IL-2. Survival of the cells after IL-2 withdrawal relies on the continuous presence of IL-7, and the cells eventually come to rest in the cultures. In this system, timed exposure of naïve CD8+ T cells to IL-12 and IL-21 generates memory cells with competent effector functions upon rechallenge, specifically strong production of IFNγ, TNFα and IL-2. The memory cells generated also have acquired a favourable phenotype associated with early differentiation status by both cell surface markers (CCR7, CD62L, CD27 and CD28) and transcription factors (eg Tcf-1). Although our system has been piloted on the expansion of naïve CD8+ T cells, we propose that this alternative protocol could be used to generate resting antigen-specific memory cells with improved efficacy in preventing or treating viral disease in immunocompromised patients.

A cost effective simulator for education of ultrasound image interpretation and probe manipulation

Ultrasonography is the lowest cost no risk medical imaging technique. However, reading an ultrasonographic (US) image as well as performing a good US probe positioning remain difficult tasks. Education in this domain is today performed on patients, thus limiting it to the most common cases. In this paper, we present a cost effective simulator that allows US image practice and realistic probe manipulation from CT data. More precisely, we tackle the issue of providing a realistic interface for the probe manipulation with a basic haptic feedback.

Application of Radiofrequency Ablation of Renal VX2Tumors by Cooled-Tip Electrode in a Rabbit Model

Objective. This study has two purposes: (a) to compare the use of tumor cell suspensions and excised tumor tissue for generating renal tumors suitable for radiofrequency ablation (RFA) studies and (b) to assess the efficacy of RFA for ablation of renal VX2 tumors in a rabbit model. Procedures. VX2 tumor masses were used to inoculate 17 rabbits. The renal VX2 tumors of 13 rabbits were subsequently treated with a cooled-tip RF system at a power of 15-30 W for 3-6 minutes, and 4 rabbits served as control. After RFA, rabbits were observed by contrast-enhanced CT to ascertain the ablative range. Rabbits were divided into three groups and sacrificed at 3, 7, and 14 days post-treatment for histopathological studies. Results. Both tumor implant methods had a 100% success rate in generating tumors. The average lesion produced was 1.3x1.8x1.5 cm. Complete tumor ablation occurred in 76.9%, and local tumor growth in 23.1%. Depending on the position of the tumors, the complications after RFA treatment included infarction, perirenal hematoma, hydronephrosis, and abscess. The over-all complication rate was 38.5%. In histopathological studies, a central needle track, tumor coagulation, renal tissue coagulation, peripheral hemorrhage, and an inflammatory layer could be observed. Conclusion and clinical relevance. Application of RFA to destroy renal VX2 tumors in this rabbit model has a relatively high cure rate. It can be used to destroy small renal tumors in a precise and non-invasive manner. Impact on human medicine. We hope to apply this procedure in selected human renal tumors in the future.

Laparoscopic combined rectal anterior resection and total hysterectomy with bilateral salpingo-oophorectomy

Pelvic conditions involving both the colorectum and gynaecological organs are traditionally treated by laparotomy. We report two cases of colorectal cancer and one of endometriosis treated by laparoscopic anterior resection and total hysterectomy bilateral salpingooophorectomy (LapAR & THBSO), at the same session. There have been no previously reported cases of the feasibility of such combined procedures, safely performed. Our results confirm that LapAR & THBSO is feasible and offers the advantages of a laparoscopic procedure in the hands of a well trained laparoscopic colorectal surgeon and gynaecologist working together.

Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27 x 10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336+/-14 events. The data are consistent with nu(mu) disappearance via oscillations with |Delta(m)2/32|=2.74 +0.44/-0.26 x10(-3)eV(2) and sin(2)(2theta(23))>0.87 (68% C.L.).

Normal anatomy and common labral lesions at MR arthrography of the shoulder

MR arthrography of the shoulder is the most accurate imaging modality in demonstrating abnormalities of the glenoid labrum and associated structures. Tears of the labrum, the capsule or the gleno-humeral ligaments can lead to pain, catching, popping or instability. The anatomy of this region is complex. We present the normal anatomy of the glenoid labrum, biceps anchor and gleno-humeral ligaments together with their normal variants and then describe common labral-ligamentous pathologies.

Molecular dynamics simulations of various coronavirus main proteinases

In this study, two homology models (denoted as MproST and MproSH) of main proteinase (Mpro) from the novel coronavirus associated with severe acute respiratory syndrome (SARS-CoV) were constructed based on the crystal structures of Mpro from transmissible gastroenteritis coronavirus (TGEV) (MproT) and human coronavirus HcoV-229E (MproH), respectively. Both MproST and MproSH exhibit similar folds as their respective template proteins. These homology models reveal three distinct functional domains as well as an intervening loop connecting domains II and III as found in both template proteins. A catalytic cleft containing the substrate binding sites S1 and S2 between domains I and II are also observed. S2 undergoes more significant structural fluctuation than S1 during the 400 ps molecular dynamics simulations because it is located at the open mouth of the catalytic cleft, while S1 is situated in the very bottom of this cleft. The thermal unfolding of these proteins begins at domain III, where the structure is least conserved among these proteins. Mpro may still maintain its proteolytic activity while it is partially unfolded. The electrostatic interaction between Arg40 and Asp186 plays an important role in maintaining the structural integrity of both S1 and S2.

Steroid sulphatase inhibitors for breast cancer therapy

In contrast to aromatase inhibitors, which are now in clinical use, the development of steroid sulphatase (STS) inhibitors for breast cancer therapy is still at an early stage. STS regulates the formation of oestrone from oestrone sulphate (E1S) but also controls the hydrolysis of dehydroepiandrosterone sulphate (DHEA-S). DHEA can be reduced to 5-androstenediol (Adiol), a steroid with potent oestrogenic properties. The active pharmacophore for potent STS inhibitors has now been identified, i.e. a sulphamate ester group linked to an aryl ring. This has led to the development of a number of STS inhibitors, some of which are due to enter Phase I trials in the near future. Such first generation inhibitors include the tricyclic coumarin-based 667 COUMATE. Aryl sulphamates, such as 667 COUMATE, are taken up by red blood cells (rbc), binding to carbonic anhydrase II (CA II), and transit the liver without undergoing first-pass inactivation. 667 COUMATE is also a potent inhibitor of CA II activity with an IC50 of 17 nM. Second generation STS inhibitors, such as 2-methoxyoestradiol bis-sulphamate (2-MeOE2bisMATE), in addition to inhibiting STS activity, also inhibit the growth of oestrogen receptor negative (ER-) tumours in mice and are anti-angiogenic. As the active pharmacaphores for the inhibition of aromatase and STS are now known it may be possible to develop third generation inhibitors that are capable of inhibiting the activities of both enzymes. Whilst exploring the potential of such a strategy it was discovered that 667 COUMATE possessed weak aromatase inhibitory properties with an IC50 of 300 nM in JEG-3 cells. The identification of potent STS inhibitors will allow the therapeutic potential of this new class of drug to be explored in post-menopausal women with hormone-dependent breast cancer. Second generation inhibitors, such as 2-MeOE2bisMATE, which also inhibit the growth of ER- tumours should be active against a wide range of cancers.

A response of Panc-1 cells to cis-platinum, assessed with a cDNA array

BACKGROUND

The problem posed by the lack of response of cells in most solid cancers to current chemotherapy generally remains intractable.

MATERIALS AND METHODS

The use of cDNA arrays represents one global approach to identifying reasons for this failure. A messenger RNA response of pancreatic cancer (Panc-1) cells after culture for 24 hours with 12 microM cis-platinum was analyzed with a commercial cDNA array.

RESULTS

Major drug-induced events included inhibition of messenger RNAs associated with cell proliferation and up-regulation of generally countervailing DNA repair, cellular stress, heat shock protein, glutathione stress-related and multiple drug resistance enzyme messenger RNAs, accompanied by a limited programmed cell death response.

CONCLUSION

Induction of widespread normal stress-induced countervailing mRNAs by comparatively non-selective agents such as cis-platinum strongly biases against a successful therapeutic outcome. This paradoxical result of a therapeutic intent provides a further compelling argument for the use of specifically-targeted therapy such as growth factor receptor, tyrosine kinase and other discretely focused agents, probably employed in combinations based on expression of their targets in an individual patient's cancer, as identified by cDNA or proteonomic arrays.

Neisseria meningitidis lipopolysaccharide modulates the specific humoral immune response to neisserial porins but has no effect on porin-induced upregulation of costimulatory ligand B7-2

The role of lipopolysaccharide (LPS) in the specific humoral response to meningococcal porins was investigated by measuring anti-PorA or -PorB antibody levels in mice immunized with wild-type meningococcal strain H44/76 or with its recently described LPS-negative mutant. Two murine strains were used for these immunizations: C3H/HeJ, which is LPS hyporesponsive, or C3H/HeOuJ, which is LPS responsive. A high level of anti-PorB immunoglobulin G (IgG) response was induced in both strains of mice immunized with either organism. The response induced by the wild-type strain was greater in C3H/HeOuJ mice than in C3H/HeJ mice, while the response induced by the LPS-negative mutant was similar in the two murine strains. Additionally, the anti-PorB response was similar in C3H/HeJ mice immunized with either bacterial strain. In general, the anti-PorA IgG response was lower than the anti-PorB response. These findings indicate that the presence of LPS is not essential for the induction of an antineisserial porin humoral response but can augment such a response. To determine whether LPS has any effect on the B-cell-stimulatory effect of neisserial porins (essential for the adjuvant activity of neisserial porins), B cells from both murine strains were incubated with outer membrane complexes (OMCs) prepared from strain H44/76 and its LPS-negative mutant. OMCs from either meningococcal strain were able to increase the surface expression of the costimulatory ligand B7-2 on B cells from either murine strain. Consistent with previously reported findings, LPS does not significantly affect the ability of neisserial porins to induce the costimulatory ligand B7-2.

Effects of olfactory bulbectomy on NMDA receptor density in the rat brain:

Olfactory bulbectomy (OBX) transects the glutamatergic efferents from the olfactory bulbs, and the changes of glutamatergic N-methyl-D-aspartate (NMDA) receptor-mediated function are though to be involved in the behavioral deficits seen in OBX rats. In the present study, irritability scores in OBX male Wistar rats were correlated with discrete regional effects on NMDA receptor function measured using a [3H] MK-801 binding assay. Irritability scores, measured before and for 2 weeks after OBX, showed a gradual increase in irritability after OBX. A reduction of the NMDA receptor density was observed in the cerebral cortex and amygdala 16 days after OBX, but not in the striatum, olfactory tubercle, entorhinal cortex, and hippocampus. These results demonstrate that OBX causes changes in the NMDA receptor system in certain brain regions and suggest that these changes may be responsible for the behavioral deficits of OBX rats.

Structural characterization of the mouse Foxf1a gene

Members in the superfamily of the forkhead/winged-helix transcription factors are known to play a critical role in the control of cell differentiation and tissue development. To understand the regulation and function of these genes, we have initially isolated and characterized the mouse Foxf1a gene, a novel forkhead gene predominantly expressed in the lung. The mouse gene consists of two exons with the forkhead domain contained in exon 1, and is located at band E1 on chromosome 8. Amino acid sequence of the mouse protein shares a high degree of homology to that of the corresponding human protein. The tissue specificity of expression of the mouse gene also resembles that found in the human gene. This gene is primarily expressed in the lung, and to a lesser extent in placenta and tissues in gastrointestinal tract. The transcription start site was mapped to 113 nucleotides upstream from the putative translation initiation site. The promoter of the mouse gene is highly GC rich and contains neither a CAAT nor a TATA box. A series of luciferase report constructs driven by the promoter and various deletions in the 5' flanking region of the gene were constructed and employed in transient transfection studies using a line of SV40 transformed mouse lymph node endothelial cells (SVEC4-10), which express the endogenous Foxf1a gene, and a line of mouse hepatoma cells (Hepa 1-6), in which Foxf1a is not expressed. To our surprise, these reporter genes are equally active in both cell lines. Further studies have shown that the proximal 5' flanking sequence and exon 1 of the endogenous gene are highly methylated in Hepa 1-6 cells but not in SVEC4-10 cells, suggesting that DNA methylation but not cell-specific transcription factor(s) regulates cell specificity of gene expression in these cultured cells.

Overexpression of CuZnSOD in coronary vascular cells attenuates myocardial ischemia/reperfusion injury

Superoxide dismutase scavenges oxygen radicals, which have been implicated in ischemia/reperfusion (I/R) injury in the heart. Our experiments were designed to study the effect of a moderate increase of copper/zinc superoxide dismutase (CuZnSOD) on myocardial I/R injury in TgN(SOD1)3Cje transgenic mice. A species of 0.8 kb human CuZnSOD mRNA was expressed, and a 273% increase in CuZnSOD activity was detected in the hearts of transgenic mice with no changes in the activities of other antioxidant enzymes. Furthermore, immunoblot analysis revealed no changes in the levels of HSP-70 or HSP-25 levels. Immunocytochemical study indicated that there was increased labeling of CuZnSOD in the cytosolic fractions of both endothelial cells and smooth muscle cells, but not in the myocytes of the hearts from transgenic mice. When these hearts were perfused as Langendorff preparations for 45 min after 35 min of global ischemia, the functional recovery of the hearts, expressed as heart rate x LVDP, was 48 +/- 3% in the transgenic hearts as compared to 30 +/- 5% in the nontransgenic hearts (p <.05). The improved cardiac function was accompanied by a significant reduction in lactate dehydrogenase release from the transgenic hearts. Our results demonstrate that overexpression of CuZnSOD in coronary vascular cells renders the heart more resistant to I/R injury.

Neisseria meningitidis porin PorB interacts with mitochondria and protects cells from apoptosis

Neisserial porins are strong immune adjuvants and B cell activators. The effect of neisserial porin PorB on activation-induced cell death was investigated, as a potential additional mechanism of the porin's immunopotentiating ability. Neisserial porins interact with target cells to localize intracellularly in the mitochondrial compartment without negatively affecting cellular survival. Pretreatment with Neisseria meningitidis PorB porin decreased or abrogated the mitochondrial damage induced by apoptotic stimuli. In addition, end stage determinants of apoptosis, including DNA breakdown, were diminished by PorB. Immunoprecipitation experiments revealed that PorB interacts with the mitochondrial porin VDAC (voltage-dependent anion channel). The mechanism of the antiapoptotic effect of neisserial porins could be explained by the protein-protein interaction of PorB with VDAC, similar to the interaction of VDAC with antiapoptotic Bcl-2 proteins, resulting in an enhancement of cell survival and continued activation of B cells.

Functional and structural studies of alpha-crystallin from galactosemic rat lenses

Chaperone-like activity and structural changes of lens alpha-crystallin from rats fed with galactose at various time intervals have been studied using high-performance liquid chromatograph (HPLC), circular dichroism (CD), and 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence emission. It was found that chaperone-like activity of alpha-crystallin from galactose-fed rats toward dithiothreitol (DTT)-induced insulin B aggregation started to decrease after 3 weeks and decreased significantly after 5 weeks. Consistent results were observed in lens morphology, and lens opacity slightly developed after 3 weeks and became obvious after 5 weeks. HPLC analysis for chaperone function showed that the formation of high molecular weight aggregates (HMWA) of alpha-/gamma-crystallins decreases with the increase of galactose-feeding time, revealing that chaperone-like activity is concomitant with the formation of HMWA. Circular dichroism results showed the reduction of beta-sheet structure and loss of microenvironment of aromatic-type amino acids for opaque lenses, indicating alpha-crystallin's secondary and tertiary structure changed with the development of the lens opacity. ANS binding site estimated by Klotz equation showed it is 1.5 times higher at room temperature and is 2.4 times higher at 58 degrees C for age-matched normal alpha-crystallin than for 5-week galactose-fed lens alpha-crystallin, indicating opaque lens alpha-crystallin loses the ability to assemble into an appropriately placed hydrophobic regions. The overall results accordingly indicated that galactose-induced cataractous alpha-crystallin has disordered structure, leading to the loss of its chaperone-like activity.

Evidence for changing of cosmic ray composition between 10(17) and 10(18) eV from multicomponent measurements

The average mass composition of cosmic rays with primary energies between 10(17) and 10(18) eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the muon density as a function of energy. The results show that the composition is changing from a heavy to lighter mix as the energy increases.

Using technetium-99M dimercaptosuccinic acid renal cortex scintigraphy to differentiate acute pyelonephritis from other causes of fever in patients with spinal cord injury

OBJECTIVES

To differentiate acute pyelonephritis (APN) from fever due to other sources in patients with spinal cord injury by using technetium-99m dimercaptosuccinic acid (DMSA) renal cortex scintigraphy (DMSA scan).

METHODS

A total of 24 patients with spinal cord injury were admitted with fever. DMSA scans were performed on all patients. The final determination of the cause of the fever was based on the medical history, physical examination, laboratory evaluation, and imaging studies.

RESULTS

DMSA scan accurately diagnosed APN in 12 patients with inflammation on the DMSA scan. In 5 patients with scarred lesions on the DMSA scans and in 7 patients with negative DMSA scan, the fever was attributed to other causes. The sensitivity and specificity of the DMSA scan for detecting APN were both 100%.

CONCLUSIONS

The DMSA scan is a valuable adjunct in the evaluation of fever in patients with SCI.

Localized brain activation by selective tasks improves specific cognitive functions in humans

Neuroimaging studies have identified cognitive tasks that can selectively activate specific parts of the brains. However, the subsequent effect of localized brain activation on the cognitive functioning remains unclear. We discovered that after being engaged in the novel picture encoding task to activate hippocampus for 2 min, individuals demonstrated better memory, but not motor function. Similarly, after performing the finger sequencing task to activate the primary motor cortex, individuals showed improvement in motor function, but not in memory. These double dissociation results suggest that when we selectively activate specific part of the brain, the cognitive function mediated by that particular region but not the others can consequently be improved.

The maturase encoded by a group I intron from Aspergillus nidulans stabilizes RNA tertiary structure and promotes rapid splicing

The AnCOB group I intron from Aspergillus nidulans self-splices, providing the Mg2+ concentration is >/= 15 mM. The splicing reaction is greatly stimulated by a maturase protein encoded within the intron itself. An initial structural and biochemical analysis of the splicing reaction has now been performed. The maturase bound rapidly to the precursor RNA (kon approximately 3 x 10(9) M(-1) min(-1)) and remained tightly bound (koff </= 0.04 min(-1)). The catalytic step of 5' splice-site cleavage occurred at a rate of up to 11 min(-1) under single turnover conditions. The maturase-assisted reaction of heat-denatured RNA proceeded at a rate of about 1 min(-1), arguing that there are early steps of folding that cannot be readily facilitated by the protein. pH analysis revealed a biphasic profile with a pKa of 7.0. The rate of the maturase-assisted reaction was independent of the Mg2+ concentration down to 3 mM. Self-splicing in optimal Mg2+ (>/= 150 mM) was tenfold slower, in part because of the existence of an equilibrium between folded and partially folded RNA. In contrast, the maturase very effectively stabilized tertiary structure in 5 mM Mg2+, a noticeable example being an interaction between the P8 helix and a GNRA sequence that constitutes the L2 terminal loop of the P2 helix. Formation of the 5' splice-site recognition helix was assisted by either the maturase or high concentrations of Mg2+. The maturase was required during splicing so it is not a true chaperone. However, RNase protection assays and kinetic studies suggest that the maturase recognizes and facilitates folding of an intron with limited tertiary structure and even incomplete secondary structure.

T lymphocyte response to Neisseria gonorrhoeae porin in individuals with mucosal gonococcal infections

T lymphocytes from a majority of patients with urogenital gonococcal disease (67%-80%) proliferated on incubation with gonococcal porin (Por), compared with minimal induced proliferation of T lymphocytes from normal volunteers. A significant increase in Por-specific interleukin (IL)-4-producing CD4+ T helper lymphocytes was seen in patients with mucosal gonococcal disease and not in normal controls. Similar results were observed in CD8+ T lymphocytes from these patients. There was no measured increase in IL-2, IL-10, IL-12, interferon-gamma, or tumor necrosis factor-alpha production by T lymphocytes from infected subjects on incubation with Por. Concomitant increases in IL-4 production in T lymphocytes from infected subjects expressing the mucosal addresin VLAalpha4/beta7 on their surface were also observed on Por incubation, but the increases were similar in T lymphocytes that were VLAalpha4/beta7 negative. In conclusion, mucosal gonococcal disease can induce Por-specific circulating T lymphocytes with a Th2 phenotype, and a portion of these Por-specific T lymphocytes can potentially traffic to mucosal surfaces.

The role of B/T costimulatory signals in the immunopotentiating activity of neisserial porin

A T cell-dependent immune response to group C meningococcal capsular polysaccharide (CPS) can be elicited when CPS is conjugated to the class 3 neisserial porin (CPS-porin). Treatment of CPS-porin-immunized mice with B7-2 blocking monoclonal antibody (MAb) caused a dramatic reduction in the CPS-specific IgG response, treatment with anti-B7-1 MAb had no effect, and concurrent blockade of B7-1 and B7-2 resulted in a synergistic abrogation of the CPS-specific IgG response while the CPS IgM response was unaffected. Anti-CD40L MAb treatment caused a significant reduction of both CPS-specific IgG and IgM levels. In contrast, blockade of CTLA4 interactions resulted in increases in both CPS IgG and IgM responses in CPS-porin-immunized mice. These data support the hypothesis that the ability of neisserial porins to improve the immune response to poorly immunogenic antigens (e.g., polysaccharides) is related to porin-induced increases in B7-2 expression on antigen-presenting cells and enhanced B/T cell interactions.