Evaluating YOLO architectures for detecting road killed endangered Brazilian animals

Wildlife roadkill is a recurring, dangerous problem that affects both humans and animals and has received increasing attention from environmentalists worldwide. Addressing this problem is difficult due to the high investments required in road infrastructure to effectively reduce wildlife vehicle collisions. Despite recent applications of machine learning techniques in low-cost and economically viable detection systems, e.g., for alerting drivers about the presence of animals and collecting statistics on endangered animal species, the success and wide adoption of these systems depend heavily on the availability of data for system training. The lack of training data negatively impacts the feature extraction of machine learning models, which is crucial for successful animal detection and classification. In this paper, we evaluate the performance of several state-of-the-art object detection models on limited data for model training. The selected models are based on the YOLO architecture, which is well-suited for and commonly used in real-time object detection. These include the YoloV4, Scaled-YoloV4, YoloV5, YoloR, YoloX, and YoloV7 models. We focus on Brazilian endangered animal species and use the BRA-Dataset for model training. We also assess the effectiveness of data augmentation and transfer learning techniques in our evaluation. The models are compared using summary metrics such as precision, recall, mAP, and FPS and are qualitatively analyzed considering classic computer vision problems. The results show that the architecture with the best results against false negatives is Scaled-YoloV4, while the best FPS detection score is the nano version of YoloV5.

Catéter Venoso Totalmente Implantável em 278 Pacientes Oncológicos

Os catéteres totalmente implantáveis proporcionam acesso vascular prolongado, baixo risco durante inserção e remoção, fácil manutenção, conforto e segurança para o paciente e baixo índice de complicações. Nosso objetivo é relatar a experiência com 278 catéteres implantados por um único cirurgião. Foram critérios para o implante: diagnóstico histopatológico, expectativa de vida maior que 3 meses, dificuldade de acesso venoso periférico e programa de quimioterapia. Entre março de 1990 e março 1998 foram implantados 278 catéteres em 272 pacientes. Tempo de permanência: 382 dias (5a 2897) totalizando 106.457 dias. Sexo feminino 64.8%. Idade média 50,2 anos. Via de acesso: jugular interna 67,9%, jugular externa 26,5%, safena 2,2%, cefálica 1,7% e subclávia 1.7%. Complicações: #1. Obstrução (0,26/1000 dias) #2. Hematoma 6,11% do total, todos em pacientes leucêmicos. #3. Extravasamento 0,2/1000 dias). #4. Trombose (0,03/1000 dias). #5. Infecção 20 episódios, 0,19/1000 dias), sendo 6 lúmen, 7 peri-port e 7 suspeita clínica de sepses. Foram retirados 34 catéteres, 26 por complicações e 8 ao término do tratamento. Permanecem vivos em uso do cateter 45,2%. Não apresentaram qualquer tipo de complicação 74,5% dos pacientes. Em nossa experiência o número de complicações é baixo. O manuseio é realizado exclusivamente por profissionais treinados. Atenção com pacientes leucêmicos para a formação de hematomas.

Factors influencing kidney transplantation rates: a study from the ERA Registry

BACKGROUND

Large international differences exist in kidney transplantation (KT) rates. We aimed to investigate which factors may explain the total, deceased donor, and living donor KT rates over the last decade.

METHODS

KT experts from 39 European countries completed the Kidney Transplantation Rate Survey on measures and barriers and their potential effect on the KT rate in their country. In the analyses, countries were divided into low, middle, and high KT rate countries based on the KT rate at the start of study period in 2010.

RESULTS

Experts from low KT rate countries reported more frequently to have taken measures regarding staff, equipment and facilities to increase total KT rate compared with middle and high KT rate countries. For donor type specific KT, the largest international differences in measures taken were reported for deceased donor KT, with middle and high KT rate countries taking more measures, such as the use of expanded criteria donor kidneys, the presence of transplantation coordinators, and (inter)national exchange of donor kidneys. Once a measure was taken, experts' opinion on its success was similar across the low, middle and high KT rate countries. Experts from low KT rate countries more often reported potential barriers, such as patients' lack of knowledge and distrust in the health care system.

CONCLUSIONS

In particular in low KT rate countries, KT rate might be stimulated by optimizing staff, equipment, and facilities. In addition, all countries may benefit from deceased and living donor specific measures.

Tip Lesion Variant of Focal and Segmental Glomerulosclerosis in a COVID-19 Patient

Acute kidney injury is a common complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Several pathologic findings are continually being reported, showing a probably multifactorial etiology. The authors present a case of a patient diagnosed with a tip lesion variant of focal segmental glomerulosclerosis (FSGS) in the setting of COVID-19. A 43-year-old African American female with no known renal disease presented to the emergency department with a 6-day history of fatigue, headache, hypoageusia, myalgia, cough, nausea, and vomiting. Laboratory tests confirmed SARS-CoV-2 infection. During hospitalization, there was a progressive decline in kidney function and evidence of nephrotic-range proteinuria without nephrotic syndrome. Biopsy specimen showed a tip lesion variant of FSGS. Genetic test revealed a homozygous variant of uncertain clinical significance (c.397G>A [p.V133M]) in the epithelial membrane protein 2 (EMP2) gene. To our knowledge, this is the first case report of a tip lesion in a COVID-19 patient with no renal history. More studies are warranted to define susceptible groups and identify the detailed mechanisms of COVID-19-related kidney disease that would allow for specific management of this complication.

Successful treatment of collapsing focal segmental glomerulosclerosis in a patient

Focal segmental glomerulosclerosis (FSGS) is a recognized cause of renal disease worldwide. The collapsing variant is distinct from the others, characterized clinically by a more severe nephrotic syndrome generally resistant to immunosuppressive therapy. It is known that a great number of patients progress to end-stage renal disease. Recognizing this lesion in biopsy is frequently challenging owing to the focal nature of the process which highlights the need for keeping a high index of suspicion for the diagnosis. We report and discuss a case of a non-HIV collapsing FSGS, followed by a complete (unexpected) renal recovery after an oral corticosteroid course.

Cryptococcosis in Renal Transplant Recipients: A Single-Center Experience

BACKGROUND

In solid organ transplant patients, 8% of invasive fungal infections are attributed to Cryptococcus. The aim of this study was to determine the frequency, risk factors, clinical characteristics, and outcome of kidney transplant recipients (TR) infected with Cryptococcus.

CASE SERIES

Between 2007 and 2014, a total of 500 kidney transplantations were performed at São João Hospital, in Porto, Portugal. Six infections by C. neoformans were reported, an incidence of 1.2% (3 disseminated, 2 meningeal, and 1 cutaneous). Patients were 65-72 years of age and 4 of 6 were male, compared with all kidney TR, among whom the mean age was 51.1 years and 60% were male. Three cases of crytococcosis occurred within the first 6 months after transplantation; 3 patients had cytomegalovirus infection and leukopenia, and 2 patients' immunosuppression had been increased in the last 6 months. Meningitis presented with headache, fever, and acute mental confusion; pulmonary involvement presented with respiratory insufficiency and infiltrative or nodular lung lesions; and cutaneous infections presented as cellulitis or skin abscess. Blood cultures for C. neoformans were positive in 3 cases; all of these patients had positive cryptococcal antigen of 1:128 to 1:8192. Five patients received liposomal amphotericin B for 9-21 days, followed by fluconazole. Four patients lost their grafts, and one patients died after a persistent vegetative state due to cryptococcal meningitis.

CONCLUSIONS

This small case series led to suspicion of an association between cryptococcosis and older age, renal dysfunction, cytomegalovirus infection, and intensification of immunosuppression after rejection episodes. In our series, cryptococcosis was associated with poor graft outcome.

Late Allograft Renal Vein Thrombosis Treated With Anticoagulation Alone: A Case Report

BACKGROUND

Allograft renal vein thrombosis is a rare complication of kidney transplantation. Most cases occur in the first 2 weeks after transplantation, but there are cases described many years after the transplant surgery. Allograft loss is the usual outcome.

METHODS

We present a case of a renal transplant recipient with allograft renal vein thrombosis associated with deep venous thrombosis of a lower limb, 9 years after transplantation. He was successfully treated with anticoagulation alone, with recovery of allograft function.

RESULTS

The patient was given unfractioned heparin and elastic compression stockings. Five days later, the patient recovered diuresis and hemodialysis treatment was discontinued. Doppler ultrasound was done and revealed partial re-permeabilization of allograft renal vein, with maximal velocity of 15 cm/s. After 30 months of follow-up, the patient was maintained on oral anticoagulation with warfarin, and no thromboembolic or hemorrhagic events were documented. The patient's serum creatinine was stable, between 1.6 and 1.8 mg/dL.

CONCLUSIONS

Our patient demonstrated that anticoagulation alone and dialytic support might be able to promote total recovery of allograft function after renal vein thrombosis.

Post-transplant Lymphoproliferative Disorder: A Single-Center Experience

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is the second most common neoplasia after adult kidney transplantation (KT).

METHODS

We retrospectively analyzed 8 adult patients who underwent KT in our center, diagnosed with PTLD between 2001 and 2014.

RESULTS

Six patients were men. The median age at presentation was 43 years and the median time since transplantation was 7.3 years. Three patients had previously received anti-thymocyte globulin/OKT3, and all were taking calcineurin inhibitors (CNI) at diagnosis. The monomorphic type was the most common, with diffuse large B-cell lymphoma as the origin. The most frequent presentation was fever. Four in five patients had Epstein-Barr-related PTLD. All patients received various regimens of immunosuppression reduction (IR), with 4 converting CNI to mTOR inhibitor (imTOR). Subsequent treatment (when needed) was chemotherapy, radiotherapy, and surgery. The maximum follow-up time was 6.7 years, with a 50% mortality rate that occurred at a median time of 3.5 months (2 died with functioning kidney). All 4 patients who were in remission at the end of follow-up had CNI conversion to imTOR, and none lost the allograft.

CONCLUSIONS

Despite the small number of cases, our results confirm the high PTLD impact in overall and allograft survival. Our PTLD type distribution is in accord with the literature. First-line PTLD treatment is IR, but the best method is still unknown; our results may suggest a beneficial effect of CNI conversion to imTOR.

Renal Transplantation in HIV-Infected Patients: The First Portuguese Review

INTRODUCTION

With the introduction of combination antiretroviral therapy (cART), prognosis of human immunodeficiency virus (HIV) infection has been improved and kidney transplantation (KT) in HIV-positive patients became possible.

METHODS

We reviewed the demographic, clinical, laboratory, and therapeutic data of all the HIV-infected patients who underwent KT between 2009 (first KT in Portugal in a HIV-infected patient) and May 2014. Case accrual was through all Portuguese KT centers where a KT in an HIV-infected patient was performed. Patients were transplanted following the American and Spanish guideline recommendations that included maintenance on cART, undetectable plasma HIV RNA copies, and absolute CD4 counts of ≥ 200 cells/μL in the last 6 months.

RESULTS

Fourteen KT were performed on men and 3 on women. The mean age of patients at the time of transplantation was 49.9 ± 11.7 years. HIV status was known for 12 ± 5 years. Eight patients had AIDS in the past and all patients received grafts from deceased donors. Twelve patients (64.7%) underwent induction therapy with basiliximab and 2 patients experienced early graft loss. In 2 patients, humoral rejection was diagnosed and in 3 patients, cellular rejection. Two patients died and an additional patient had early graft loss.

CONCLUSION

KT is a possible, but challenging, renal replacement therapy in selected HIV-positive patients. Even in those with AIDS criteria in the past, when the disease is controlled, and after the reconstitution of the immune system with cART, KT can be performed. Nevertheless, the risk-benefit ratio for each patient needs to be taken in consideration.

Renal transplantation in human immunodeficiency virus-positive patients: a report of four cases

INTRODUCTION

Renal transplantation (RT) in patients infected with human immunodeficiency virus (HIV) has significantly improved under the advent of combined antiretroviral therapy (cART). The authors describe their experience in RT in patients with HIV from September 2010 to June 2013.

CASES REPORT

Four patients underwent transplantation (3 with HIV-1 and 1 with HIV-2), three patients were male, and one was black. None were coinfected with hepatitis B virus (HBV) or hepatitis C virus (HCV). Etiology of kidney disease was HIV-associated nephropathy (2 patients), immunoglobulin (Ig)A nephropathy, and unknown. Average age at RT was 51 (range, 41-63) years. No patient was of high immunologic risk. Immunosuppression consisted of basiliximab for induction and prednisolone, tacrolimus (TAC), and mycophenolate mofetil for maintenance. TAC levels varied considerably in the early days (8.5-46 ng/mL), requiring major adjustments in TAC dose. Only the HIV-2 patient had delayed graft function. The follow-up of patients with HIV-1 was 37, 19, and 16 months, and 3 months for the HIV-2 patient. CD4+ T cells decreased in the early days after transplantation with subsequent improvement, along with persistent virological suppression. In the HIV-1 group there were no major infectious, cardiovascular, or neoplastic complications. Nevertheless, the HIV-2 patient died 3 months after RT due to H1N1 pneumonia complicated by pulmonary aspergillosis. Average estimated (CKD- EPI) glomerular filtration rate (eGFR) at 6 months was 85.6 mL/min/1.73 m(2).

CONCLUSION

Besides the difficulty in adjusting calcineurin inhibitors levels due to its interaction with antiretroviral therapy, namely with protease inhibitors, no patient had acute rejection. Furthermore, all patients presented an excellent control of viro-immunologic parameters. At the last follow-up neither cardiovascular events nor neoplastic complications were observed. Our results highlight the favorable outcome of RT in HIV-1-infected patients. The HIV-2 patient died due to severe infection, and the clinical management and potential benefit of RT in HIV-2-infected patients needs further study.

Collagen type IV-related nephropathies in Portugal: pathogenic COL4A3 and COL4A4 mutations and clinical characterization of 25 families

Pathogenic mutations in genes COL4A3/COL4A4 are responsible for autosomal Alport syndrome (AS) and thin basement membrane nephropathy (TBMN). We used Sanger sequencing to analyze all exons and splice site regions of COL4A3/COL4A4, in 40 unrelated Portuguese probands with clinical suspicion of AS/TBMN. To assess genotype-phenotype correlations, we compared clinically relevant phenotypes/outcomes between homozygous/compound heterozygous and apparently heterozygous patients. Seventeen novel and four reportedly pathogenic COL4A3/COL4A4 mutations were identified in 62.5% (25/40) of the probands. Regardless of the mutated gene, all patients with ARAS manifested chronic renal failure (CRF) and hearing loss, whereas a minority of the apparently heterozygous patients had CRF or extrarenal symptoms. CRF was diagnosed at a significantly younger age in patients with ARAS. In our families, the occurrence of COL4A3/COL4A4 mutations was higher, while the prevalence of XLAS was lower than expected. Overall, a pathogenic COL4A3/COL4A4/COL4A5 mutation was identified in >50% of patients with fewer than three of the standard diagnostic criteria of AS. With such a population background, simultaneous next-generation sequencing of all three genes may be recommended as the most expedite approach to diagnose collagen IV-related glomerular basement membrane nephropathies.

Collagen type IV-related nephropathies in Portugal: pathogenic COL4A5 mutations and clinical characterization of 22 families

Alport syndrome (AS) is caused by pathogenic mutations in the genes encoding α3, α4 or α5 chains of collagen IV (COL4A3/COL4A4/COL4A5), resulting in hematuria, chronic renal failure (CRF), sensorineural hearing loss (SNHL) and ocular abnormalities. Mutations in the X-linked COL4A5 gene have been identified in 85% of the families (XLAS). In this study, 22 of 60 probands (37%) of unrelated Portuguese families, with clinical diagnosis of AS and no evidence of autosomal inheritance, had pathogenic COL4A5 mutations detected by Sanger sequencing and/or multiplex-ligation probe amplification, of which 12 (57%) are novel. Males had more severe and earlier renal and extrarenal complications, but microscopic hematuria was a constant finding irrespective of gender. Nonsense and splice site mutations, as well as small and large deletions, were associated with younger age of onset of SNHL in males, and with higher risk of CRF and SNHL in females. Pathogenic COL4A3 or COL4A4 mutations were subsequently identified in more than half of the families without a pathogenic mutation in COL4A5. The lower than expected prevalence of XLAS in Portuguese families warrants the use of next-generation sequencing for simultaneous COL4A3/COL4A4/COL4A5 analysis, as first-tier approach to the genetic diagnosis of collagen type IV-related nephropathies.

Discovering implicit associations in a case of encapsulating peritoneal sclerosis complicated by severe mineral imbalance

We describe the case of a 42-year-old woman who developed encapsulating peritoneal sclerosis (EPS) after 7 years on peritoneal dialysis, with clinical relief by enterolysis associated to treatment with tamoxifen, corticosteroids and parenteral nutrition in haemodialysis. During the next 7 months, she was also conservatively stabilised for mild hyperparathyroidism until she was admitted with calciphylaxis, associated with massive extraosseous calcification. Despite parathyroidectomy and sodium thiosulfate treatment, which resulted in a successful resolution of calciphylaxis, she died 1 year later due to a gross calcified peritoneum. In view of controlled hyperparathyroidism, the massive extraosseous calcification beginning after EPS diagnosis furthermore corroborates a recently suggested role for calcium-regulatory factors associated with poor outcome in EPS.

Classification systems for lower extremity amputation prediction in subjects with active diabetic foot ulcer: a systematic review and meta-analysis

AIM

We systematically review the available systems used to classify diabetic foot ulcers in order to synthesize their methodological qualitative issues and accuracy to predict lower extremity amputation, as this may represent a critical point in these patients' care.

MATERIAL AND METHODS

Two investigators searched, in EBSCO, ISI, PubMed and SCOPUS databases, and independently selected studies published until May 2013 and reporting prognostic accuracy and/or reliability of specific systems for patients with diabetic foot ulcer in order to predict lower extremity amputation.

RESULTS

We included 25 studies reporting a prevalence of lower extremity amputation between 6% and 78%. Eight different diabetic foot ulcer descriptions and seven prognostic stratification classification systems were addressed with a variable (1-9) number of factors included, specially peripheral arterial disease (n = 12) or infection at the ulcer site (n = 10) or ulcer depth (n = 10). The Meggitt-Wagner, S(AD)SAD and Texas University Classification systems were the most extensively validated, whereas ten classifications were derived or validated only once. Reliability was reported in a single study, and accuracy measures were reported in five studies with another eight allowing their calculation. Pooled accuracy ranged from 0.65 (for gangrene) to 0.74 (for infection).

CONCLUSION

There are numerous classification systems for diabetic foot ulcer outcome prediction, but only few studies evaluated their reliability or external validity. Studies rarely validated several systems simultaneously and only a few reported accuracy measures. Further studies assessing reliability and accuracy of the available systems and their composing variables are needed.

Validation and comparison of currently available stratification systems for patients with diabetes by risk of foot ulcer development

AIMS/HYPOTHESIS

There are five systems to stratify the risk for the development of a diabetic foot ulcer (DFU). This study aimed to prospectively validate all of them in the same cohort of participants to allow their direct comparison.

METHODS

A retrospective cohort study was conducted on all patients with diabetes but without an active DFU attending our podiatry section (n=364) from January 2008 to December 2010. Participants' characteristics and all variables composing the stratification systems were assessed at baseline. Follow-up was performed for 1 year or until DFU occurred.

RESULTS

Participants had a mean age of 64 years; 99.7% had type 2 diabetes and 48.6% were male. Median follow-up was 12 months (1-12) during which 33 subjects (9.1%) developed a DFU. Age, diabetes duration, foot deformity, peripheral vascular disease, diabetic peripheral neuropathy, previous DFU, and previous lower extremity amputation were associated with DFU occurrence. All systems presented greater DFU occurrence frequency as the risk group was higher (χ(2), P<0.001) and showed good diagnostic accuracy values, especially negative predictive value (≥ 95%) and area under the receiver operating curve (≥ 0.73). The lowest performance concerned positive predictive value (≤ 29.5%).

CONCLUSIONS/INTERPRETATION

All the currently available stratification systems show high accuracy to detect which patients will develop a DFU with no significant differences among them. Therefore, for diabetic foot screening and resource allocation, it would be desirable to have a single unified system, combining the available systems, prospectively validated in a multicenter context and testing the inclusion of novel predictive variables' pertinence.

Rituximab for steroid-dependent nephrotic syndrome

Minimal change disease (MCD) is characterized by marked sensitivity to glucocorticoid therapy. However, in 40 - 50% of all cases the disease presents with frequent relapses and needs repeated courses of steroids as well as additional immunosuppressive therapy including azathioprine, cyclophosphamide or cyclosporine. Because such regimens are associated with significant toxicity, the therapeutic challenge of this disease is to identify the treatment with the highest probability of producing a sustained remission with the lowest risk of toxicity. There is increasing evidence that rituximab may play an important role in the treatment of idiopathic nephrotic syndrome. Here, we present an adult patient with steroid-sensitive but high-dose steroid-dependent MCD beginning in childhood with a heavy history of multiple immunosuppressive therapy that was brought into 1 year sustained remission of proteinuria with two infusions of rituximab (375 mg/m2).

[Hybrid treatment of an aortic arch aneurysm]

Traditional open repair of aortic arch aneurysms is a complex and demanding surgery that requires cardiopulmonary bypass, hypothermia and circulatory arrest, being associated with considerable morbidity and mortality. Even with significant advances in pre-operative assessment and optimization, advanced anaesthetic techniques and intensive care, conventional aortic arch repairs remain amongst the highest risk of across all surgical specialties. Therefore, a hybrid approach with sequential transposition of the supra-aortic branches and endovascular stent-graft placement is a less invasive alternative treatment that opens the indication for repair to more critical patients. We report our institution's first experience in the hybrid surgery of aortic arch aneurysms.

[Supra-aortic trunks occlusive disease: three different treatment approaches]

Unlike carotid bifurcation atherosclerotic stenosis, supra-aortic trunks (SAT) occlusive disease is rare and its revascularization uncommon, accouting for less than 10% of the operations performed on the extracranial brain-irrigating arteries. There are three different treatment approaches: transthoracic, extra-anatomic cervical and endovascular. Endovascular repair is gaining popularity as first-line therapy for proximal lesions with favorable anatomy because of its low morbidity and rare mortality. Extra-anatomic bypass is a safe and durable reconstruction and should be considered in patients with single vessel disease, with cardiopulmonary high-risk or with limited life expectancy. If cardiac surgery is needed, central transthoracic reconstruction is preferable, and the two procedures should be combined. The long-term patency of bypasses with aortic origin, specially when multiple vessels are involved, is superior to other repair techniques. We present three clinical cases that illustrate each of these therapeutic strategies: central brachiocephalic revascularization and synchronous cardiac surgery in a patient with complex SAT atherosclerosis disease; subclavian-carotid transposition for disabling upper limb claudication; and subclavian artery stenting for subclavian-steal syndrome. Surgical approach selection should be based on the individual patient's anatomy and operative risk.

Incorporating Domain-Specific Information Quality Constraints into Database Queries

The range of information now available in queryable repositories opens up a host of possibilities for new and valuable forms of data analysis. Database query languages such as SQL and XQuery offer a concise and high-level means by which such analyses can be implemented, facilitating the extraction of relevant data subsets into either generic or bespoke data analysis environments. Unfortunately, the quality of data in these repositories is often highly variable. The data is still useful, but only if the consumer is aware of the data quality problems and can work around them. Standard query languages offer little support for this aspect of data management. In principle, however, it should be possible to embed constraints describing the consumer’s data quality requirements into the query directly, so that the query evaluator can take over responsibility for enforcing them during query processing.

Most previous attempts to incorporate information quality constraints into database queries have been based around a small number of highly generic quality measures, which are defined and computed by the information provider. This is a useful approach in some application areas but, in practice, quality criteria are more commonly determined by the user of the information not by the provider. In this article, we explore an approach to incorporating quality constraints into database queries where the definition of quality is set by the user and not the provider of the information. Our approach is based around the concept of a quality view , a configurable quality assessment component into which domain-specific notions of quality can be embedded. We examine how quality views can be incorporated into XQuery, and draw from this the language features that are required in general to embed quality views into any query language. We also propose some syntactic sugar on top of XQuery to simplify the process of querying with quality constraints.

Inflammation, homocysteine and carotid intima-media thickness

INTRODUCTION

Cardiovascular disease is the main cause of morbidity and mortality in chronic renal patients. Carotid intima-media thickness (CIMT) is one of the most accurate markers of atherosclerosis risk. In this study, the authors set out to evaluate a population of chronic renal patients to determine which factors are associated with an increase in intima-media thickness.

METHODS

We included 56 patients (F=22, M=34), with a mean age of 68.6 years, and an estimated glomerular filtration rate of 15.8 ml/min (calculated by the MDRD equation). Various laboratory and inflammatory parameters (hsCRP, IL-6 and TNF-alpha) were evaluated. All subjects underwent measurement of internal carotid artery intima-media thickness by high-resolution real-time B-mode ultrasonography using a 10 MHz linear transducer.

RESULTS

Intima-media thickness was used as a dependent variable in a simple linear regression model, with the various laboratory parameters as independent variables. Only parameters showing a significant correlation with CIMT were evaluated in a multiple regression model: age (p=0.001), hemoglobin (p=00.3), logCRP (p=0.042), logIL-6 (p=0.004) and homocysteine (p=0.002). In the multiple regression model we found that age (p=0.001) and homocysteine (p=0.027) were independently correlated with CIMT. LogIL-6 did not reach statistical significance (p=0.057), probably due to the small population size.

CONCLUSION

The authors conclude that age and homocysteine correlate with carotid intima-media thickness, and thus can be considered as markers/risk factors in chronic renal patients.

Body Composition Assessed by Impedance Changes Very Early with Declining Renal Graft Function

BACKGROUND

Kidney transplant (Tx) restores renal filtration, although it does not achieve the function of two native kidneys, and with time it may variably involute back to chronic renal failure. We hypothesized that bioelectrical impedance analysis (BIA) might highlight differences for body compartments among Tx with different filtration rates, and we compared them with healthy controls.

METHODS

38 Tx patients (25 males, 13 females) were studied at 75.9 +/- 37.8 months postsurgery and divided into three groups: good creatinine clearance (CrCl, ml/min/1.73 m2; > 65.0), borderline (35.0 < CrCl < 60.0) and bad (CrCl < 35.0). BIA was assessed three times in a year. Total body water, extracellular water (ECW), intracellular water (ICW), Na:K exchange rate (Nae:Ke) and phase angle were studied. Healthy (n = 11) and hemodialysis (n = 11) groups were also studied.

RESULTS

BIA showed no differences between healthy controls and good Tx while both borderline and bad Tx presented a significantly higher ECW and lower ICW than either good Tx or normal controls. Only good CrCl was different from predialysis.

CONCLUSIONS

A good kidney graft manages to restore and maintain normal body composition, even with potential disturbances brought about by steroids and cyclosporine. With mild renal dysfunction a change in body compartments was observed, moving towards the composition of that with chronic renal failure patients.

Tyrosinase-catalyzed modification of Bombyx mori silk fibroin: Grafting of chitosan under heterogeneous reaction conditions

The capability of mushroom tyrosinase to catalyze the oxidation of tyrosine residues of Bombyx mori silk fibroin was studied under heterogeneous reaction conditions, by using a series of silk substrates differing in surface and bulk morphology and structure, i.e. hydrated and insoluble gels, mechanically generated powder and fibre. Tyrosinase was able to oxidize 10-11% of the tyrosine residues of silk gels. The yield of the reaction was very low for the powder and undetectable for fibres. FT-Raman spectroscopy gave evidence of the oxidation reaction. New bands attributable to vibrations of oxidized tyrosine species (o-quinone) appeared, and the value of the I853/I829 intensity ratio of the tyrosine doublet changed following oxidation of tyrosine. The thermal behaviour of SF substrates was not affected by enzymatic oxidation. o-Quinones formed by tyrosinase onto gels and powder were able to undergo non-enzymatic coupling with chitosan. FT-IR and FT-Raman spectroscopy provided clear evidence of the formation of silk-chitosan bioconjugates under heterogeneous reaction conditions. Chitosan grafting caused a beta-sheet --> random coil conformational transition of silk fibroin and significant changes in the thermal behaviour. Chitosan grafting did not occur, or occurred at an undetectable level on silk fibres. The results reported in this study show the potential of the enzymatically initiated protein-polysaccharide grafting for the production of a new range of bio-based, environmentally friendly polymers.

Nutritional Status and Body Composition Evolution in Early Post–Renal Transplantation: Is There a Female Advantage?

OBJECTIVE

Chronic renal failure is associated with metabolic derangements, affecting proteins, amino acids, and lipids. Usually these patients follow a restricted diet. Kidney transplant patients enjoy a recovery of renal function, but their therapeutics may entail significant changes in general metabolism. We compare the anthropometric results during the first 3 months after successful transplant for male and female patients versus a healthy group.

METHODS

Eighteen patients (11 men and 7 women) were studied. Anthropometry was assessed before and at month 1 and month 3 posttransplant including body weight (Wt), body mass index (BMI), triceps (TSF), biceps (BSF), subscapular (SCSF), and suprailiac skinfolds (SISF), midarm circumference (MAC), midarm muscle circumference (MAMC), corrected arm muscle area (CT.AMA), total body muscle mass (MM), body density (D), fat mass (FM), and fat-free mass (FFM). The healthy group was evaluated three times in the first year.

RESULTS

Pretransplant men showed lower Wt, BMI, TSF, BSF, SCSF, SISF, MAC, MAMC, CT.AMA, MM, FM and FFM than controls, while women displayed no differences from controls. By the third month, men showed only a partial recovery and women higher TSF and SCSF than controls.

CONCLUSIONS

Uremic men before transplant displayed undernutrition indices. During the first 3 months posttransplant men showed an incomplete recovery of anthropometric parameters. Quite differently, women started close to normal and had significantly increased body weight and fat content posttransplant. We suggest that nutritional requirements post-kidney grafting may be significantly different among male compared to female patients.

Enzymatic grafting of chitosan onto Bombyx mori silk fibroin: kinetic and IR vibrational studies

The potential for using tyrosinase to graft the polysaccharide chitosan (Ch) onto Bombyx mori silk fibroin (SF) was examined. FT-IR spectroscopy coupled to HPLC amino acid analysis showed that mushroom tyrosinase (MT) catalyses the oxidation of tyrosine (Tyr) of SF to electrophilic o-quinones. Kinetic studies showed that only a fraction of the Tyr residues available on the SF chain were oxidized. This result was interpreted in the light of the structure assumed by SF in aqueous solution: Tyr aromatic side chain groups buried into the folded hydrophobic portions of the chain were probably less accessible to MT for steric reasons. Using slightly acidic conditions (pH 6), it was possible to modify SF under homogeneous conditions. FT-IR spectroscopy provided evidence that Ch was grafted onto MT-oxidized SF: the o-quinones were found to undergo a subsequent non-enzymatic reaction with nucleophilic amino groups of Ch via Schiff-base and Michael addition mechanisms. Various factors, i.e. reaction time, pH, MT/SF ratio, were found to influence the grafting yield. The highest grafting yield was achieved at pH 7, i.e. more favorable to MT activity rather than to Ch solubility, suggesting that the determining step of the grafting reaction is the formation of o-quinones. The FT-IR spectroscopy revealed that grafting induced a beta-sheet --> random coil conformational transition.