Bacterial Contamination of Tissue Allografts – Experiences of the Donor Tissue Bank of Victoria

The aim of this study is to report the experience of the Donor Tissue Bank of Victoria with bacteria isolated from musculoskeletal, skin and cardiac allografts retrieved from cadaveric donors. The results of all quality control samples for bacterial culture, taken during retrieval and processing of allografts at the DTBV for a 12 month period, were extracted and analysed. It was found that 15.7% of skin, 15.1% of heart valves and 5.8% of musculoskeletal samples had positive culture results. The number and types of organisms isolated varied with tissue type. The most commonly isolated organisms were Staphylococcus species (including S. aureus). The identity of the isolate and the number of positive specimens from the same donor were considerations in the decision concerning the suitability of tissue for subsequent implantation.     

Skin Donors Positive for HBV Core Antibodies – to Bank or Not to Bank? An Overview from a Regional Tissue Bank

A prompt transplantation of skin allografts on patients with severe, large body area burns is a preferred treatment, but depends on a suitable supply of tissue donors. Limiting factors include donors' identification, families consent, and following the standards – exclusion due to assessed transmissible diseases. To increase the current rate of skin donations to our regional skin bank, we reviewed the data of all potential organ donors, identified at Soroka University Medical Center from October 1997 to December 2000 and evaluated the causes for exclusion, especially due to HBV serological profile. 114/168 (67.9%) patients did not meet the indicated standards for organ donation, among which 20/114 patients (17.5%) positive for anti-HBc (anti-HBc⁺). 54/168 persons were declared brain dead, with consents obtained from 21 families. To discuss the intriguing approval of skin from potential donors with anti-HBc⁺ serology, the literature was reviewed, specifically – the reported outcomes of organ transplants from anti-HBc⁺ donors, updates of HBV and skin, available tests, and finally a look for a safe commendable algorithm. The results suggested that HBV might be replicating in the skin, but proven communication of HBV has not been reported following grafting skin from anti-HBc⁺ donors. Unlike other procured organs and tissues, grafted banked skin is a temporary cover, storable up to six years, under appropriate conditions. Hence, banking of skin from anti-HBc⁺ donors might be considered for future grafting of patients with identical serological profiles, presumably immune to a subsequent HBV infection, until a further re-evaluation of the standards. This procedure is anticipated to increase the potential of organ and tissue donations, specifically skin.     

Banking of cryopreserved arterial allografts in Europe: 20 years of operation in the European Homograft Bank (EHB) in Brussels

Vascular allografts have been used for many years in patients with infection complications and when the patient lacks own autologous venous material. Cryopreservation has permitted the long term storage of these allografts, offering the optimal solution for particular clinical situations. For more than 20 years the European Homograft Bank has prepared, stored in the liquid nitrogen vapour below ?130 °C and distributed various types of the quality controlled arterial allografts throughout the European centers and elsewhere. The tissues are prepared according to the existing European, Belgian, Swiss and other EU countries’ regulations and standards. This paper gives an overview of this activity since 1991. During this period 1,428 batches of arteries were received from recovery centres within European Union and Switzerland and 3,941 arterial segments were evaluated. 1,250 (32 %) were discarded for morphological findings (58 %), bacteriology (31 %) and other reasons, while 2,685 or 68 % (ascending and descending aorta, arch, aortic bifurcation, iliac and femoral arteries and the non-valved pulmonary bifurcations) were cryopreserved and stored. 2,506 arteries were implanted in 1,600 patients in vascular and cardiac centers in European Union and elsewhere. The most important indications were infections (65 %), critical limb ischemia (15 %) and congenital cardiac malformations (15 %). Some allografts were used for the repair of arterial injury (2 %) or prosthetic graft thrombosis (1.5 %). 10 aortic allografts (0.4 %) were used for tracheal replacement in case of cancer. In 52 cases EHB did not fulfill the surgeon’s requests due to shortage of arterial allografts. Collaboration with vascular surgeons in the tissue recovery might improve the number, diversity and quality of vascular allografts. A multicentric study is necessary to evaluate the long-term outcome of these allografts.     

From Membrane Pores to Aquaporins: 50 Years Measuring Water Fluxes

This review focuses on studies of water movement across biological membranes performed over the last 50 years. Different scientific approaches had tried to elucidate such intriguing mechanism, from hypotheses emphasizing the role of the lipid bilayer to the cloning of aquaporins, the ubiquitous proteins described as specific water channels. Pioneering and clarifying biophysical work are reviewed beside results obtained with the help of recent sophisticated techniques, to conclude that great advances in the subject live together with old questions without definitive answers.     

Improvements in 25 Years of Implantable Cardioverter Defibrillator Therapy

In 1980, Dr. Michel Mirowski and his team inserted the first implantable cardioverter defibrillator (ICD) in a patient. Initially, ICD therapy was not widely accepted, and many physicians actually considered this therapy unethical. Large secondary and primary prevention trials, demonstrating a beneficial effect of ICD therapy in selected patients not only on arrhythmic death but also on all-cause mortality, stimulated a rapid growth in the number of implants and increased patient’s and physician’s acceptance. Improvements in size and weight, arrhythmia discrimination capabilities, battery technology, shock waveform and output, monitoring capabilities and defibrillator electrode technology eventually resulted in the current large number of yearly implants. Today, almost 40 years after the conception of the ICD and 25 years after the first human implant, ICD therapy is the treatment of choice for patients at risk for life-threatening arrhythmias either as secondary or primary prevention. Furthermore, with the more recent addition of resynchronisation therapy to standard ICD therapy, it became possible to treat selected patients with advanced symptoms of heart failure and to lower the risk of sudden death.     

Generalized Voronoi Tessellation as a Model of Two-dimensional Cell Tissue Dynamics

Voronoi tessellations have been used to model the geometric arrangement of cells in morphogenetic or cancerous tissues, however, so far only with flat hyper-surfaces as cell-cell contact borders. In order to reproduce the experimentally observed piecewise spherical boundary shapes, we develop a consistent theoretical framework of multiplicatively weighted distance functions, defining generalized finite Voronoi neighborhoods around cell bodies of varying radius, which serve as heterogeneous generators of the resulting model tissue. The interactions between cells are represented by adhesive and repelling force densities on the cell contact borders. In addition, protrusive locomotion forces are implemented along the cell boundaries at the tissue margin, and stochastic perturbations allow for non-deterministic motility effects. Simulations of the emerging system of stochastic differential equations for position and velocity of cell centers show the feasibility of this Voronoi method generating realistic cell shapes. In the limiting case of a single cell pair in brief contact, the dynamical nonlinear Ornstein–Uhlenbeck process is analytically investigated. In general, topologically distinct tissue conformations are observed, exhibiting stability on different time scales, and tissue coherence is quantified by suitable characteristics. Finally, an argument is derived pointing to a tradeoff in natural tissues between cell size heterogeneity and the extension of cellular lamellae.     

Synchronization of Early Afterdepolarizations and Arrhythmogenesis in Heterogeneous Cardiac Tissue Models

Early afterdepolarizations (EADs) are linked to both triggered arrhythmias and reentrant arrhythmias by causing premature ventricular complexes (PVCs), focal excitations, or heterogeneous tissue substrates for reentry formation. However, a critical number of cells that synchronously exhibit EADs are needed to result in arrhythmia triggers and substrates in tissue. In this study, we use mathematical modeling and computer simulations to investigate EAD synchronization and arrhythmia induction in tissue models with random cell-to-cell variations. Our major observations are as follows. Random cell-to-cell variations in action potential duration without EAD presence do not cause large dispersion of refractoriness in well-coupled tissue. In the presence of phase-2 EADs, the cells may synchronously exhibit the same number of EADs or no EADs with a very small dispersion of refractoriness, or synchronize regionally to result in large dispersion of refractoriness. In the presence of phase-3 EADs, regional synchronization leads to propagating EADs, forming PVCs in tissue. Interestingly, even though the uncoupled cells exhibit either no EAD or only a single EAD, when these cells are coupled to form a tissue, more than one PVC can occur. When the PVCs occur at different locations and time, multifocal arrhythmias are triggered, with the foci shifting in space and time in an irregular manner. The focal arrhythmias either spontaneously terminate or degenerate into reentrant arrhythmias due to heterogeneities and spatiotemporal chaotic dynamics of the foci.     

Cutaneous and Bone Marrow Histoplasmosis After 18 Years of Renal Allograft Transplant

The frequency of histoplasmosis among solid organ transplant (SOT) recipients appears to be low where there are only a few case series, mostly among renal and liver transplant recipients. Herein we report a case of a 44-year-old woman who underwent a living-related renal transplant 18 years prior to evaluation, developed a nodule after followed by ulceration upon her posterior right leg and a second one upon her left leg 3 months and 2 months before her hospitalisation, respectively. The biopsy of lesion revealed the presence of Histoplasma spp. Bone marrow aspiration was performed and also revealed the same organism. She had initially received itraconazole without improvement of lesions, while a new lesion appeared on her left arm. Healing of all lesions could be observed after 40 days of liposomal amphotericin B when she was submitted to skin grafts on the legs and a surgical treatment on the arms, and the myelosuppression improved simultaneously. Histoplasmosis seems to be very uncommon among patients who underwent to organ solid transplantation. Most cases occur within 12–18 months after transplantation, although unusual cases have been presented many years post-transplant. There are cases reported in the literature, occurring from 84 days to 18 years after organ transplantation, but without cutaneous involvement. Our patient developed lesions on limbs and myelosuppression after 18 years of chronic immunosuppression medication. This case suggests that besides cutaneous histoplasmosis is an uncommon infection following iatrogenic immunosuppression and even rarer over a long period after the transplantation. Clinicians who care SOT recipient patients must bear in mind histoplasmosis infection as differential diagnosis in any case of cutaneous injury with prolonged fever and try to use as many tools as possible to make the diagnosis, once this disease presents a good prognosis if it is diagnosed and treated promptly.     

Vegetation Dynamics on an Abandoned Vacuum-Mined Peatland: 5 Years of Monitoring

We studied from 1998 to 2002 the fine-scale vegetation dynamics of a poorly regenerated vacuum-mined bog located in southern Quebec. We selected mined sites that have been abandoned for 14 years and monitored the vascular and non-vascular plants, and some hydrological characteristics. We focussed our study on the monitoring of cotton-grass (Eriophorum vaginatum L.) tussocks. Major changes in the plant cover were observed during the five-year period, such as a decrease (26–31%) in the number of cotton-grass tussocks and an increase in the ericaceous shrub cover. The water table level (lower than 40 cm below the soil surface) and frost heaving appear to be the main factors explaining the failure of cotton-grass and of other typical bog plant species to colonize abandoned mined surfaces. The ericaceous shrub cover, although increasing, was still sparse even after two decades of abandonment, and it may take several additional decades before a complete shrub cover establishes itself. While the natural revegetation process of this vacuum-mined bog is still dynamic after two decades of abandonment, there is no evidence to suggest that vegetation assemblages will eventually resemble those of undisturbed peatlands.     

Genetic Polymorphisms and the Risk of Myocardial Infarction in Patients Under 45 Years of Age

This study investigates the potential role of 17 chosen polymorphisms in 15 candidate genes and the risk of myocardial infarction in patients under 45 years of age. The study consists of 271 patients with myocardial infarction and 141 controls. The analysis of genetic polymorphisms was performed using the PCR–RFLP method. Of the chosen polymorphisms, two (Leu125Val PECAM1 and A1/A2 FVII) are related to myocardial infarction and two (C677T MTHFR and 5A/6A MMP3) to advanced stenosis in arterial vessels (> 75%). We also found that the frequency of some combinations among the analyzed genes and environmental factors varied between the patient and control groups.     

Brief History of the Tissue Bank, Charles University Hospital, Hradec Králové, Czech Republic

A brief history of the Tissue Bank (TB) of the University Hospital Hradec Králové, Czech Republic, established by Dr. R. Klen in 1952 is presented. In Dr. Klen's original concept the TB was defined as a department specialised in the harvesting, processing, preservation, storage and distribution of various kinds of tissue for clinical and experimental practice. The first kinds of tissue collected in cadaveric donors were corneas, bone and skin. Xenogeneic cartilage and bone grafts were prepared at the same time. Later, preparation of soft connective tissues and chorion–amnion was introduced. During the first 15 years of activity a total of 11,443 grafts preserved by hypothermy at +4°C or freezing in absence of cryoprotectants (–20°C) were prepared. In the 60's freeze-drying of tissue grafts was introduced and the bank of cryopreserved cell lines was established. In the 80's cryopreservation of haematopoietic progenitor cells for clinical transplantations was started and the spectrum of tissue grafts was enlarged (xenogeneic pericardium and allogeneic specially treated dura mater for neurosurgical operations, pigskin for burn treatment, demineralised bone for parodontology and implantology). In the 90's human keratinocyte culture for treatment of burns and chronic skin defects was started. The human milk bank and organ bank co-operating with the Regional Transplantation Centre are component parts of the TB as well. The TB is an institutional member of the European Association of Tissue Banks and annually delivers approximately 1000 grafts that are used in University and county hospitals as well as in surgeons' private practices. Health insurance companies reimburse all grafts on a non-profit and tax-free basis.     

Groundwater arsenic contamination in Bangladesh—21 Years of research

Department of Public Health Engineering (DPHE), Bangladesh first identified their groundwater arsenic contamination in 1993. But before the international arsenic conference in Dhaka in February 1998, the problem was not widely accepted. Even in the international arsenic conference in West-Bengal, India in February, 1995, representatives of international agencies in Bangladesh and Bangladesh government attended the conference but they denied the groundwater arsenic contamination in Bangladesh. School of Environmental Studies (SOES), Jadavpur University, Kolkata, India first identified arsenic patient in Bangladesh in 1992 and informed WHO, UNICEF of Bangladesh and Govt. of Bangladesh from April 1994 to August 1995. British Geological Survey (BGS) dug hand tube-wells in Bangladesh in 1980s and early 1990s but they did not test the water for arsenic. Again BGS came back to Bangladesh in 1992 to assess the quality of the water of the tube-wells they installed but they still did not test for arsenic when groundwater arsenic contamination and its health effects in West Bengal in Bengal delta was already published in WHO Bulletin in 1988. From December 1996, SOES in collaboration with Dhaka Community Hospital (DCH), Bangladesh started analyzing hand tube-wells for arsenic from all 64 districts in four geomorphologic regions of Bangladesh. So far over 54,000 tube-well water samples had been analyzed by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). From SOES water analysis data at present we could assess status of arsenic groundwater contamination in four geo-morphological regions of Bangladesh and location of possible arsenic safe groundwater. SOES and DCH also made some preliminary work with their medical team to identify patients suffering from arsenic related diseases. SOES further analyzed few thousands biological samples (hair, nail, urine and skin scales) and foodstuffs for arsenic to know arsenic body burden and people sub-clinically affected. SOES and DCH made a few follow-up studies in some districts to know their overall situations after 9 to 18 years of their first exposure. The overall conclusion from these follow-up studies is (a) villagers are now more aware about the danger of drinking arsenic contaminated water (b) villagers are currently drinking less arsenic contaminated water (c) many villagers in affected village died of cancer (d) arsenic contaminated water is in use for agricultural irrigation and arsenic exposure from food chain could be future danger. Since at present more information is coming about health effects from low arsenic exposure, Bangladesh Government should immediately focus on their huge surface water management and reduce their permissible limit of arsenic in drinking water.     

Modelling Soft Tissue Using Biphasic Theory — A Word of Caution

In recent years the biphasic approach initiated by Mow and coworkers, has been very popular in modelling soft, hydrated, cartilage tissues as well as other soft tissues, such as the brain. This work points out that due to the inherent inability of biphasic models in their present form to account for stress-strain rate dependence resulting from the viscoelasticity of the solid phase, the applicability of these models is limited to the loading conditions producing large relative velocities of phases.     

Tissue banking in Bangladesh: 12 years of experience (2003–2014)

Tissue Banking and Biomaterial Research Unit (TBBRU), the only tissue bank of Bangladesh, has been established to create an available supply of human tissue allografts for transplantation in Bangladesh. Since its establishment in 2003, TBBRU strictly follows the guidelines of tissue banking setup by the International Atomic Energy Agency, the European Association of Tissue Banks and the American Association of Tissue Banks. Though started serving from earlier, regular supply of tissue allografts from this bank were documented at the end of 2006. From January 2007 to December 2014, 3747 bones and 5772 amniotic sacs were collected from live tissue donors. During this period, 59,489 cc bone allografts and 23,472 pieces of amniotic membrane allografts were processed. In the same period, 58,483 cc bone allografts and 20,786 pieces membrane were supplied to different hospitals throughout the country on the basis of demand. The outcomes of the concerted efforts of tissue banking professionals and physicians were the restoration of health and hope of 3662 patients during the last 8 years.