A Mycobacterial Systems Resource for the Research Community

Functional characterization of bacterial proteins lags far behind the identification of new protein families. This is especially true for bacterial species that are more difficult to grow and genetically manipulate than model systems such as Escherichia coli and Bacillus subtilis To facilitate functional characterization of mycobacterial proteins, we have established a Mycobacterial Systems Resource (MSR) using the model organism Mycobacterium smegmatis This resource focuses specifically on 1,153 highly conserved core genes that are common to many mycobacterial species, including Mycobacterium tuberculosis, in order to provide the most relevant information and resources for the mycobacterial research community. The MSR includes both biological and bioinformatic resources. The biological resource includes (i) an expression plasmid library of 1,116 genes fused to a fluorescent protein for determining protein localization; (ii) a library of 569 precise deletions of nonessential genes; and (iii) a set of 843 CRISPR-interference (CRISPRi) plasmids specifically targeted to silence expression of essential core genes and genes for which a precise deletion was not obtained. The bioinformatic resource includes information about individual genes and a detailed assessment of protein localization. We anticipate that integration of these initial functional analyses and the availability of the biological resource will facilitate studies of these core proteins in many Mycobacterium species, including the less experimentally tractable pathogens M. abscessus, M. avium, M. kansasii, M. leprae, M. marinum, M. tuberculosis, and M. ulceransIMPORTANCE Diseases caused by mycobacterial species result in millions of deaths per year globally, and present a substantial health and economic burden, especially in immunocompromised patients. Difficulties inherent in working with mycobacterial pathogens have hampered the development and application of high-throughput genetics that can inform genome annotations and subsequent functional assays. To facilitate mycobacterial research, we have created a biological and bioinformatic resource (https://msrdb.org/) using Mycobacterium smegmatis as a model organism. The resource focuses specifically on 1,153 proteins that are highly conserved across the mycobacterial genus and, therefore, likely perform conserved mycobacterial core functions. Thus, functional insights from the MSR will apply to all mycobacterial species. We believe that the availability of this mycobacterial systems resource will accelerate research throughout the mycobacterial research community.

Frequency, profile and results of patients with acute heart failure transferred directly to home hospitalisation from emergency departments

OBJECTIVE

To describe the frequency, clinical characteristics and outcomes of patients with acute heart failure (AHF) transferred directly from emergency departments to home hospitalisation (HH) and to compare them with those hospitalised in internal medicine (IM) or short-stay units (SSU).

METHOD

We included patients with AHF transferred to HH by hospitals that considered this option during the Epidemiology of Acute Heart Failure in Spanish Emergency Departments (EAHFE) 4-5-6 Registries and compared them with patients admitted to IM or SSU in these centres. We compared the adjusted all-cause mortality at 1 year and adverse events 30 days after discharge.

RESULTS

The study included 1473 patients (HH/IM/SSU: 68/979/384). The HH rate was 4.7% (95% CI, 3.8-6.0%). The patients in HH had few differences compared with those hospitalised in IM and SSUs. The HH mortality was 1.5%, and the HH median stay was 7.5 days (IQR, 4.5-12), similar to that of IM (median stay, 8 days; IQR, 5-13; p=.106) and longer than that of SSU (median stay, 4 days; IQR, 3-7; p<.001). The all-cause mortality at 1 year for HH did not differ from that of IM (HR, 0.91; 95% CI, 0.73-1.14) or SSU (HR, 0.77; 95% CI, 0.46-1.27); however, the emergency department readmission rate during the 30 days postdischarge was lower than that of IM (HR, 0.50; 95% CI, 0.25-0.97) and SSU (HR, 0.37; 95% CI, 0.19-0.74). There were no differences in the need for new hospitalisations or in the 30-day mortality rate.

CONCLUSIONS

Direct transfer from the emergency department to HH is infrequent despite being a safe option for a certain patient profile with AHF.

Frequency, profile, and outcomes of patients with acute heart failure transferred directly to home hospitalization from emergency departments

OBJECTIVE

To describe the frequency, clinical characteristics and outcomes of patients with acute heart failure (AHF) transferred directly from emergency departments to home hospitalisation (HH) and to compare them with those hospitalised in internal medicine (IM) or short-stay units (SSU).

METHOD

We included patients with AHF transferred to HH by hospitals that considered this option during the Epidemiology of Acute Heart Failure in Spanish Emergency Departments (EAHFE) 4-5-6 Registries and compared them with patients admitted to IM or SSU in these centres. We compared the adjusted all-cause mortality at 1 year and adverse events 30 days after discharge.

RESULTS

The study included 1473 patients (HH/IM/SSU:68/979/384). The HH rate was 4.7% (95% CI 3.8-6.0%). The patients in HH had few differences compared with those hospitalised in IM and SSUs. The HH mortality was 1.5%, and the HH median stay was 7.5 days (IQR, 4.5-12), similar to that of IM (median stay, 8 days; IQR, 5-13; p = .106) and longer than that of SSU (median stay, 4 days; IQR, 3-7; p < .001). The all-cause mortality at 1 year for HH did not differ from that of IM (HR, 0.91; 95% CI 0.73-1.14) or SSU (HR, 0.77; 95% CI 0.46-1.27); however, the emergency department readmission rate during the 30 days postdischarge was lower than that of IM (HR, 0.50; 95% CI 0.25-0.97) and SSU (HR, 0.37; 95% CI 0.19-0.74). There were no differences in the need for new hospitalisations or in the 30-day mortality rate.

CONCLUSIONS

Direct transfer from the emergency department to HH is infrequent despite being a safe option for a certain patient profile with AHF.

Abstract P3-03-16: Intraoperative evaluation of sentinel lymph nodes after neoadjuvant systemic therapy in breast cancer

Introduction:

Intraoperative evaluation of sentinel lymph nodes (SLN) in breast cancer patients are performed using Touch preparation (TP) and/or frozen section (FS). Touch preparation for intraoperative evaluation of SLN is quick and known to be a highly sensitive and specific method for detection of metastasis. Detecting metastases in SLN intraoperatively can be challenging in patients who receive neoadjuvant systemic therapy (NST). In our hospitals, we have been routinely evaluating SLN intraoperatively in patients who have undergone (NST), including those with known metastasis to an axillary lymph node (LN) prior to therapy.

Objective:

To compare the sensitivity and specificity of TP and frozen section (FS) in the intraoperative evaluation of SLN in the neoadjuvant setting.

Material and Methods:

This retrospective review study was approved by the institutional review board. Four hundred ninety-eight SLN from 142 patients were included in this study. The intraoperative results for TP and FS were compared with the final pathology results. Relevant clinical and pathological findings such as type of surgery, tumor grade, histologic subtype, and size of metastasis were reviewed.

Results:

Of the 498 SLN evaluated intraoperatively, 341 were by TP only, 57 by FS only and 100 by both.

Of the 341 SLN examined by TP only, 313 (92%) were interpreted as negative and 28 (8%) as positive for carcinoma intraoperatively. Eighteen LN turned out to be false negative (FN) with no false positives (FP) (sensitivity=62%, specificity=100%). In the false negative cases, 12 LN had micrometastasis, 6 macrometastasis and 1 showed isolated tumor cells (ITC). The size of the macrometastatic ranged from 3 mm to 10 mm.

Of the 57 LN examined by FS only, 48 were true negative and 9 were true positive (sensitivity=100%, specificity=100%).

Of the 100 LN evaluated by both TP and FS, 59 were interpreted as negative and 41 as positive for carcinoma. There were 8 false negatives and 1 false positive (sensitivity=83%, specificity=98%). Of the 8 false negatives, 7 showed micrometastasis and 1 LN had ITC.

Discussion:

In neoadjuvant cases, both the primary tumor as well as lymph node metastases can show therapy effect such as fibrosis, necrosis and/or histiocytic aggregates. Evaluating SLN in NST cases can be challenging secondary to these effects. The TP slides are often paucicellular in SLN with treatment effect. Residual tumor cells are often trapped in a fibrotic scar and do not transfer onto the TP slide leading to low sensitivity. Therefore, for optimal intraoperative evaluation of SLN in NST cases, frozen section with or without touch preparation, is recommended.

Citation Format: Sahoo S, Mir M, Sarode V, Fang Y, Peng Y, Gwin K, Hwang H. Intraoperative evaluation of sentinel lymph nodes after neoadjuvant systemic therapy in breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-16.

High-dose benznidazole in a 62-year-old Bolivian kidney transplant recipient with Chagas central nervous system involvement

There is little published data on benznidazole dosing, or levels in cerebrospinal fluid. In this report, we describe the clinical course of an immunosuppressed patient with Chagas central nervous system involvement. He was treated successfully with larger benznidazole doses than are recommended, in order to reach therapeutically effective concentrations in the brain.

Comparison of serum levels of IL-18 in peripheral blood of patients with type II diabetes with nephropathy clinical protests and patients with type II diabetes without nephropathy clinical protests

BACKGROUND AND AIM

Interleukin (IL)-18 is a proinflammatory cytokine secreted from mononuclear cells. Serum concentration of IL-18 is a strong predictor of death in patients with cardiovascular diseases. Recent studies have shown that microinflammation is involved in the pathogenesis of diabetic nephropathy as well as of cardiovascular diseases. This study aimed to test the hypothesis that the serum level of IL-18 is a common predictor of nephropathy and atherosclerosis in patients with type 2 diabetes.

MATERIALS AND METHODS

69 diabetic patient that have documented file in two centers (Ali asghar hospital and dialysis center of Imam ali hospital) had selected. 32 patients with type 2 nephropathic diabetes and 37 age- and sex-matched control subjects with type 2 diabetes that haven't any sign and symptom of nephropathy were enrolled.then take 5 ml blood from peripheral veins. Patients with positive CRP were excluded(2 patients in control group and 1 patient in case group). We assessed measured serum IL-18 levels in all patients.

FINDINGS

Serum IL-18 levels were significantly elevated in patients with type 2 diabetes with nephropathy as compared with control subjects (serum IL-18 261.29±20.25 vs. 167.20±13.48 pg/ml, P<0.001. the all patients in case control have upper level of serum IL-18 vs the control group.

DISCUSSION AND CONCLUSIONS

Serum levels of IL-18 in nephropathic patient significantly rise and Serum levels of IL-18 might be a predictor factor of progression of diabetic nephropathy.

Bone density, microarchitecture, and material strength in chronic kidney disease patients at the time of kidney transplantation

Bone health is assessed by bone mineral density (BMD). Other techniques such as trabecular bone score and microindentation could improve the risk of fracture's estimation. Our chronic kidney disease (CKD) patients presented worse bone health (density, microarchitecture, mechanical properties) than controls. More than BMD should be done to evaluate patients at risk of fracture.

INTRODUCTION

BMD measured by dual-energy X-ray absorptiometry (DXA) is used to assess bone health in end-stage renal disease (ESRD) patients. Recently, trabecular bone score (TBS) and microindentation that can measure microarchitectural and mechanical properties of bone have demonstrated better correlation with fractures than DXA in different populations. We aimed to characterize bone health (BMD, TBS, and strength) and calcium/phosphate metabolism in a cohort of 53 ESRD patients undergoing kidney transplantation (KT) and 94 controls with normal renal function.

METHODS

Laboratory workout, lumbar spine/hip BMD measurements (using DXA), lumbar spine TBS, and bone strength were carried out. The latter was assessed with an impact microindentation device, standardized as percentage of a reference value, and expressed as bone material strength index (BMSi) units. Multivariable linear regression was used to study differences between cases and controls adjusted by age, gender, and body mass index.

RESULTS

Among cases, serum calcium was 9.6 ± 0.7 mg/dl, phosphorus 4.4 ± 1.2 mg/dl, and intact parathyroid hormone 214 pg/ml [102-390]. Fourteen patients (26.4%) had prevalent asymptomatic fractures in spinal X-ray. BMD was significantly lower among ESRD patients compared to controls: lumbar 0.966 ± 0.15 vs 0.982 ± 0.15 (adjusted p = 0.037), total hip 0.852 ± 0.15 vs 0.902 ± 0.13 (adjusted p < 0.001), and femoral neck 0.733 ± 0.15 vs 0.775 ± 0.12 (adjusted p < 0.001), as were TBS (1.20 [1.11-1.30] vs 1.31 [1.19-1.43] (adjusted p < 0.001)) and BMSi (79 [71.8-84.2] vs 82. [77.5-88.9] (adjusted p = 0.005)).

CONCLUSIONS

ESRD patients undergoing transplant surgery have damaged bone health parameters (density, microarchitecture, and mechanical properties) despite acceptably controlled hyperparathyroidism. Detecting these abnormalities may assist in identifying patients at high risk of post-transplantation fractures.

Circulating NK-cell subsets in renal allograft recipients with anti-HLA donor-specific antibodies

Detection of posttransplant donor-specific anti-HLA antibodies (DSA) constitutes a risk factor for kidney allograft loss. Together with complement activation, NK-cell antibody-dependent cell mediated cytotoxicity (ADCC) has been proposed to contribute to the microvascular damage associated to humoral rejection. In the present observational exploratory study, we have tried to find a relationship of circulating donor-specific and non donor-specific anti-HLA antibodies (DSA and HLA non-DSA) with peripheral blood NK-cell subsets and clinical features in 393 renal allograft recipients. Multivariate analysis indicated that retransplantation and pretransplant sensitization were associated with detection of posttransplant DSA. Recipient female gender, DR mismatch and acute rejection were significantly associated with posttransplant DSA compared to HLA non-DSA. In contrast with patients without detectable anti-HLA antibodies, DSA and HLA non-DSA patients displayed lower proportions of NK-cells, associated with increased CD56(bright) and NKG2A(+) subsets, the latter being more marked in DSA cases. These differences appeared unrelated to retransplantation, previous acute rejection or immunosuppressive therapy. Although preliminary and observational in nature, our results suggest that the assessment of the NK-cell immunophenotype may contribute to define signatures of alloreactive humoral responses in renal allograft recipients.

Label-free detection of DNA hybridization and single point mutations in a nano-gap biosensor

We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50 nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

The impact of the RGD peptide on osteoblast adhesion and spreading on zinc-substituted hydroxyapatite surface

The incorporation of zinc into the hydroxyapatite structure (ZnHA) has been proposed to stimulate osteoblast proliferation and differentiation. Another approach to improve cell adhesion and hydroxyapatite (HA) performance is coating HA with adhesive proteins or peptides such as RGD (arginine-glycine-aspartic acid). The present study investigated the adhesion of murine osteoblastic cells to non-sintered zinc-substituted HA disks before and after the adsorption of RGD. The incorporation of zinc into the HA structure simultaneously changed the topography of disk's surface on the nanoscale and the disk's surface chemistry. Fluorescence microscopy analyses using RGD conjugated to a fluorescein derivative demonstrated that ZnHA adsorbed higher amounts of RGD than non-substituted HA. Zinc incorporation into HA promoted cell adhesion and spreading, but no differences in the cell density, adhesion and spreading were detected when RGD was adsorbed onto ZnHA. The pre-treatment of disks with fetal bovine serum (FBS) greatly increased the cell density and cell surface area for all RGD-free groups, overcoming the positive contribution of zinc to cell adhesion. The presence of RGD on the ZnHA surface impaired the effects of FBS pre-treatment possibly due to competition between FBS proteins and RGD for surface binding sites.

De novo kidney transplant recipients need higher doses of Advagraf compared with Prograf to get therapeutic levels

INTRODUCTION

Advagraf is a new modified-release once-daily formulation of tacrolimus with a similar efficacy and safety profile to twice-daily tacrolimus (Prograf) according to clinical trials. Few data are published about its use in clinical practice, outside of sponsored clinical trials. We compared efficacy and basic pharmacokinetics of once-daily and twice-daily tacrolimus in de novo renal transplantation.

METHODS

The Advagraf group included 26 de novo renal cases who had received initial immunosuppression with once-daily tacrolimus (0.2 mg/kg from day 1 posttransplantation) combined with mycophenolic acid, steroids, and anti-CD25 monoclonal antibodies (2 doses). We compared them with a Prograf group of 26 transplants performed immediately before, who received equivalent immunosuppression with twice-daily tacrolimus (0.2 mg/kg from day 1).

RESULTS

We did not observe significant differences between groups in demographics, efficacy, and basic pharmacokinetics, namely, tacrolimus trough levels at 7, 15, 30, 60, or 90 days. We found that recipients on Advagraf needed significantly higher tacrolimus doses per kg up to 6 months post-transplantation than those on Prograf: 0.16 vs 0.11; 0.14 vs 0.08; and 0.12 vs 0.08 mg/kg at 1, 3, and 6 months. No patient suffered severe liver dysfunction. There were no differences between groups in the administration of drugs interacting with CYP3A4 or prokinetics, which could alter tacrolimus pharmacokinetics.

CONCLUSIONS

Among de novo renal cases, the new once-daily formulation of tacrolimus offered a similar short-term efficacy profile as the twice-daily tacrolimus. But it was necessary to use up to a 50% higher dose of Advagraf than Prograf to achieve similar trough levels during the first 6 months.

Epidemiology of tuberculosis in the Americas: the Stop TB strategy and the millennium development goals

BACKGROUND

Tuberculosis (TB), a preventable and curable disease, remains a major public health threat in the poorest regions of the Americas. The DOTS strategy was implemented to control TB in the region in 1993, and the new Stop TB strategy, emphasizing high-quality DOTS expansion, in 2006.

OBJECTIVES

To describe TB epidemiology in the region of the Americas from 1994 to 2005 and to analyze the progress made towards and prospects for achieving Goal 6 of the Millennium Development Goals (MDGs) by 2015.

METHODS

TB incidence, mortality and prevalence rates as well as DOTS coverage and DOTS treatment success rates were collated from the World Health Organization (WHO) databases from 1994 to 2005.

RESULTS

DOTS coverage and DOTS treatment success rates rose steadily from 1994 to 2005, with 88% of the population covered under DOTS by 2005, and an 80% success rate by the end of 2004. The TB incidence, prevalence and mortality rates have also decreased steadily from 1994 to date, but differ with respect to the various scenarios.

CONCLUSIONS

With the exception of some countries, further reduction in TB incidence, prevalence and deaths by 2015 is possible. Widespread implementation of DOTS should continue in order to meet WHO targets and attain the MDGs.

Tumor necrosis factor alpha and interferon gamma cooperatively induce oxidative stress and motoneuron death in rat spinal cord embryonic explants

The accumulation of reactive microglia in the degenerating areas of amyotrophic lateral sclerosis (ALS) tissue is a key cellular event creating a chronic inflammatory environment that results in motoneuron death. We have developed a new culture system that consists in rat spinal cord embryonic explants in which motoneurons migrate outside the explant, growing as a monolayer in the presence of glial cells. The proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) have been proposed to be involved in ALS-linked microglial activation. In our explants, the combined exposure to these cytokines resulted in an increased expression of the pro-oxidative enzymes inducible nitric oxide synthase (iNOS), the catalytic subunit of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, gp91(phox) and cyclooxygenase-2 (COX-2), as compared to each cytokine alone. This effect was related to their cooperation in the activation of the transcription factor nuclear factor kappa B (NF-kappaB). TNF-alpha and IFN-gamma also cooperated to promote protein oxidation and nitration, thus increasing the percentage of motoneurons immunoreactive for nitrotyrosine. Apoptotic motoneuron death, measured through annexin V-Cy3 and active caspase-3 immunoreactivities, was also found cooperatively induced by TNF-alpha and IFN-gamma. Interestingly, these cytokines did not affect the viability of purified spinal cord motoneurons in the absence of glial cells. It is proposed that the proinflammatory cytokines TNF-alpha and IFN-gamma have cooperative/complementary roles in inflammation-induced motoneuron death.

Profile of non traumatic surgical disorders found in the pilgrims/trekkers travelling to Shri Amarnath Ji cave

BACKGROUND & OBJECTIVES

The "Shri Amarnath Ji Yatra" is an annual congregation in which the devotees trek a difficult route of around 40 km to reach to a cave at a height of approximately 14,000 feet at Pahalgam in the State of Jammu & Kashmir, India. These trekkers are subjected to stress and strain of the long mountainous route and difficult security scenario as a result of which they are prone to develop some surgical disorders. We ascertained the profile of non-traumatic surgical conditions met in these people at the various medical aid centres and the base hospital Pahalgam so that a policy could be framed to prevent these conditions.

METHODS

This study was conducted at the Government Base Hospital Pahalgam, Kashmir, between June and August 2006. The patients with non traumatic surgical conditions attending the hospital were included in this study. Necessary investigations were done and patients requiring surgical intervention were operated upon.

RESULTS

Of the 1,54,000 devotees who undertook the "yatra", in 2006 the personnel of the Directorate of Health Services, Kashmir, extended medical aid to 40,082 pilgrims. Of these 40,082 pilgrims, 172 were admitted on the surgical side for various non traumatic surgical disorders. The commonest cause for admission was exacerbation of acid peptic diseases. Nine emergency surgical procedures were conducted at the base hospital and the commonest cause for intervention was perforation of a duodenal ulcer. There was no mortality and the patients responded well to conservative ulcer procedures.

INTERPRETATION & CONCLUSION

The stress of high altitude trekking and assembly of a large gathering of people during the annual "Amarnath Ji yatra" can pose a number of health related problems especially in the old and infirm people as was observed in the study. Pilgrims who intend taking up the yatra in future should seek medical advice prior to their departure. If a person is diagnosed to have peptic ulcer disease he or she should be put on anti-ulcer therapy to prevent potential complications.

X-ray powder diffraction structural characterization of Pb1-xBaxZr0.65Ti0.35O3 ceramic

The structure of Pb(1-x)Ba(x)Zr(0.65)Ti(0.35)O(3) (PBZT) ceramic materials with 0.00 < or = x < or = 0.40 was studied using synchrotron X-ray powder diffraction data. According to the Rietveld refinements, the structure of PBZT ceramics with x = 0.00, 0.10 and 0.20 at room temperature was rhombohedral R3c. A phase transition from rhombohedral to cubic was observed at 543 and 463 K for x = 0.10 and 0.20, respectively. The refinement for the compositions x = 0.30 and x = 0.40 showed a cubic structure from 10 to 450 K, in good agreement with the dielectric properties of these samples.

A comparative SEM study between hand instrument and Er:YAG laser scaling and root planing

Scaling and root planing are one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time-consuming. In search for more efficient and less difficult instrumentation, investigators have proposed lasers as alternatives or adjuncts for scaling and root planing. The aim of the present study was to compare the effectiveness of subgingival scaling and root planing with erbium: yttrium, aluminium, garnet (Er:YAG) laser and hand instrumentation in vitro. The mesial and distal surfaces of 15 periodontal loosed extracted teeth were treated randomly either by hand instrumentation or by Er:YAG laser irradiation. After choosing the "very long pulse mode" (pulse duration of about 700 micros), the output energy of 160 mJ with 920-microm beam diameter (RO7 Perio tip, Fidelis, Fotona, Slovenia) and frequency of 12 Hz were selected, both according to the best results of past studies. In addition, air water spray was used during the procedures. The morphology of the root surface was evaluated by three observers with a scanning electron microscopy in magnifications of 50x and 400x. The result of this setting showed that the rate of remained roughness on treated root surfaces in two groups of hand instruments and Er:YAG laser had a meaningful difference: The surface roughness in Er:YAG laser group was more than in hand instruments group. The present study could demonstrate the in vitro capability of the Er:YAG laser for scaling and root planing in periodontitis, although the effectiveness of this setting did not reach that achieved by hand instrumentation. It could be concluded that lower frequency and long pulse duration maybe more suitable for the micro-morphology of root surface after treatment. This theory is going to be tested with the same laser instrument in the next study.

X-ray diffraction single-crystal structure characterization of iron ludwigite from room temperature to 15 K

Iron ludwigite exhibits a superstructure between 283 and 144 K. Anomalies in its transport properties are due to a structural transition related to a charge-ordering phenomenon in the low-dimensional structure. This ordering produces a commensurate transversal charge density wave in the system. To understand these structural characteristics, an X-ray single-crystal diffraction study has been performed at 300 and 15 K. No changes were found in the crystalline structure, except for contraction of the cell volume. The bond-valence sum for each cation shows that at room temperature each Fe4—Fe2—Fe4 triad is composed of three Fe3+ions with one extra electron per triad, and at 15 K in each Fe4a—Fe2—Fe4btriad the extra electron is accommodated in the Fe4a—Fe2 pair of each triad.

Recurrence of IgA Nephropathy and Henoch-Schönlein Purpura After Kidney Transplantation: Risk Factors and Graft Survival

BACKGROUND

IgA nephropathy (IgA) is one of the most common glomerulonephritis. Renal transplantation is the treatment of choice for patients with ESRD due to any kind of glomerulopathy, including IgA and Henoch-Schönlein purpura nephritis (H-SP), but original disease recurrence is now the third most frequent cause of allograft loss.

METHODS

Eighty-seven cases of glomerulonephritis as the original disease were divided in two groups: group A--37 affected with 31 IgA and 6 H-SP; and group B--50 with other glomerulopathies. We compared patient and graft survivals at 5 years. To assess the presence of IgA or H-SP recurrence in group A patients, we performed an allograft biopsy in the presence of microhematuria, proteinuria, or an increased plasma creatinine. Known risk factors influencing recurrence rate were also analyzed.

RESULTS

Five-year patient (97% vs 95%) and graft survivals (81% vs 78%) were not significantly different between groups A and B. Patients with crescentic glomerulonephritis (CGN) at the moment of diagnosis of IgA or H-SP showed a 5-year graft survival of 71% in contrast with 100% graft survival among those with mesangial or focal and segmental glomerulosclerosis pattern (P = .03). Histological recurrence was diagnosed in eight patients: six IgA and two H-SP. Women (P = .013) and a good HLA match (P = .029) were significantly associated with the risk of recurrence.

CONCLUSIONS

When compared with other glomerulonephritis patients, with IgA or S-HP showed similar 5-year graft and patient survivals. Nevertheless, graft survival was shorter among patients with crescentic glomerulonephritis at the moment of diagnosis. Thus, the disease prognosis after grafting may be linked to the initial histological aggressiveness. Women and those patients transplanted with a good HLA match were prone to develop disease recurrence with a tendency toward a lower 5-year graft survival.

Towards a fast-responding, label-free electrochemical DNA biosensor

DNA sensors and sensor arrays (biochips) have become an important tool in molecular biology and biotechnology in recent years. For low-throughput, easy-to-use devices it is desirable that they be of low cost, reagentless, and label-free. Displacement sensors with electrochemical detection offer these advantages, and therefore the development of such a detection principle is show in this work. An HRP-labeled oligonucleotide was sub-optimally pre-hybridized with a capture probe and was displaced upon introduction of the fully complementary probe target, producing a decrease in signal that was proportional to the sample concentration. This detection scheme has been demonstrated colorimetrically and electrochemically, obtaining a total signal displacement of 55% only 5 min after introduction of the sample.

Posttransplant lymphoproliferative disease: treatment and outcome in renal transplant recipients

Posttransplant lymphoproliferative disorders (PTLD) are a heterogeneous group of lymphoid diseases that occur after solid organ and bone marrow transplantation. We performed a retrospective study to assess the incidence, response to treatment, and patient and graft survival after PTLD.

PATIENTS

Between January 1980 and December 2002, 1.96% (n=10) of 509 renal transplant recipients developed PTLD. Seventy percent were men. Mean age was 40 years (range 21-65). They were classified into four groups based upon the type of PTLD: group I, early lesion (n=1); group II, polymorphic PTLD (n=1); group III, monomorphic PTLD (n=7) including five non-Hodgkin lymphoma [NHL] and two Burkitt (BL); and group IV, Hodgkin lymphoma (HL) (n=1). The mean time from transplantation to diagnosis was 77 months (range 4-138). Although only 20% of cases were early presentation, Epstein-Barr virus (EBV) was found in the tumor cells of seven cases. Treatment was individualized according to PTLD type: for group I, immunosuppression reduction (IR); group II, IR plus acyclovir; group III, withdrawal or IR plus chemotherapy and/or surgery in all but one patient who was also treated with anti-CD20 monoclonal antibody and radiotherapy. Interferon was also used in one patient. For group IV, treatment was IR plus radiotherapy.

RESULTS

A complete response was achieved in nine cases (90%) with one recurrence. Three patients returned to dialysis. One patient with BL died.

CONCLUSIONS

The incidence of PTLD in our center was 1.96%. Patient survival after PTLD was 90%, with 60% maintaining allograft function. Individualized treatment according to extension, histology, and location is mandatory to obtain a high survival rate.

Structural transition and pair formation in Fe3O2BO3

We observe for the first time a structural phase transition in the oxyborate Fe3O2BO3 which occurs along three leg ladders present in this material. X-ray diffraction shows that this transition at 283 K is associated with a new phase where atomic displacements occur in alternate directions perpendicular to the axis and within the plane of the ladders. Magnetic data show that these displacements lead to the formation of singlet pairs which dissociate close to the structural transition. Anomalies in the transport properties also occur close to 283 K showing that the structural transition is related to a charge ordering phenomenon in a low dimensional structure.

Reflex sympathetic dystrophy syndrome of the lower limbs in a renal transplant patient treated with tacrolimus

BACKGROUND

Recently, a previously unrecognized posttransplant syndrome known as reflex sympathetic dystrophy syndrome of the lower limbs has emerged in patients receiving cyclosporine as immunosuppression. We describe herein this complication observed in a patient treated with tacrolimus after kidney transplantation.

METHODS

A 49-year-old man received a kidney transplant from a cadaver donor and was treated with tacrolimus. Three months later, the patient complained of severe pain in the lower limbs that affected both knees and ankles. Bone scintigraphy and magnetic resonance were consistent with reflex sympathetic dystrophy syndrome.

RESULTS

Laboratory tests that included creatinine, glomerular filtration rate, calcium, phosphate, urate, alkaline phosphatase, and parathormone were normal or near normal. Tacrolimus levels were around 13 microg/ml. Clinical improvement appeared slowly and spontaneously during the following 3 months, without appreciable changes in the tacrolimus level.

CONCLUSIONS

In kidney transplant patients, tacrolimus could be a risk factor for the development of a reflex sympathetic dystrophy syndrome.

99mTc-labelled red blood cell scintigraphy for localization of gastrointestinal bleeding in chronic renal failure

Angiodysplasia (AD) may be the source of bleeding in patients with gastrointestinal hemorrhage, with special occurrence in the elderly population and in patients with chronic renal failure (CRF). Although several techniques have been tested for its diagnosis, the gold standard is not well defined yet. We analyze the usefulness of 99mTc-labelled red blood cell (99mTc RBC) scintigraphy in the localization of bleeding from AD lesions in a cohort of 21 patients. Other investigative methods include fibrocolonoscopy examination, angiography, or diagnostic laparotomy. Group A (AD and CRF): 11 patients. Group B (AD without CRF): 10 patients. 99mTc RBC scintigraphy showed 88.9% sensitivity and specificity in group A, while in group B it had 100% sensitivity and specificity. Arteriography showed 100% sensitivity and specificity. On the contrary, fibrocolonoscopy had a very low sensitivity (30%). Our results suggest that 99mTc RBC scintigraphy may be the preferred diagnostic tool for AD, especially in patients with CRF, in whom arteriography may accelerate the decline of renal function.