Crystallisation Degree Analysis during Cryopreservation of Biological Tissue Applying Interval Arithmetic.

This paper presents the numerical modelling of heat transfer and changes proceeding in the homogeneous sample, caused by the crystallisation phenomenon during cryopreservation by vitrification. Heat transfer was simulated in a microfluidic system in which the working fluid flowed in micro-channels. The analysed process included single-phase flow during warming, and two-phase flow during cooling. In the model under consideration, interval parameters were assumed. The base of the mathematical model is given by the Fourier equation, with a heat source including the degree of ice crystallisation. The formulated problem has been solved using the interval version of the finite difference method, with the rules of the directed interval arithmetic. The fourth order Runge-Kutta algorithm has been applied to determine the degree of crystallisation. In the final part of this paper, examples of numerical computations are presented.

Numerical Study of Heat and Mass Transfer during Cryopreservation Process with Application of Directed Interval Arithmetic.

In the present paper, numerical modelling of heat and mass transfer proceeding in a two-dimensional axially symmetrical articular cartilage sample subjected to a cryopreservation process is presented. In the model under consideration, interval parameters were assumed. The heat transfer process is described using the Fourier interval equation, while the cryoprotectant transport (DMSO) across the cell membrane is analyzed using a two-parameter model taking into account the simulation of the water volume in the chondrocytes and the change in DMSO concentration over time. The liquidus tracking (LT) protocol introduced by Pegg et al. was used to model the cryopreservation process. This procedure divides the heating and cooling phases into eight and seven steps, respectively, allowing precise regulation of temperature and cryoprotectant (CPA) concentration of bathing solutions. This protocol protects chondrocytes from ice crystal, osmotic stress, and electrolyte damage. The obtained interval concentrations of cryoprotectant in chondrocytes were compared with previous simulations obtained using the deterministic model and they are mostly in agreement with the simulation data.

Single-dose rATG induction at renal transplantation: superior renal function and glucoregulation with less hypomagnesemia.

BACKGROUND: Rabbit anti-thymocyte globulin (rATG) induction reduces reperfusion injury and improves renal function in kidney recipients by means of properties unrelated to T-cell lysis. Here, we analyze intensive rATG induction (single dose, rATG(S) , vs. divided dose, rATG(D) ) for improved renal function and protection against hyperglycemia. METHODS: Patients without diabetes (n = 98 of 180) in a prospective randomized trial of intensive rATG induction were followed for six months for the major secondary composite end point of impaired glucose regulation (hyperglycemia and new-onset diabetes after transplantation, NODAT). Prospectively collected data included fasting blood glucose and HbA(1c). Serum Mg(++) was routinely collected and retrospectively analyzed. RESULTS: Induction with rATG(S) produced less impaired glucose regulation (p = 0.05), delayed NODAT development (p = 0.02), less hyperglycemia (p = 0.02), better renal function (p = 0.04), and less hypomagnesemia (p = 0.02), a factor associated with a lower incidence of NODAT. Generalized linear modeling confirmed that rATG(S) protects against a synergistic interaction between tacrolimus and sirolimus that otherwise increased hypomagnesemia (p = 0.008) and hyperglycemia (p = 0.03). CONCLUSIONS: rATG(S) initiated before renal reperfusion improved early renal function and reduced impaired glucose regulation, an injury by diabetogenic maintenance agents (tacrolimus and sirolimus).

[Problems of diagnosis and therapy of primary hyperparathyroidism--case report]. / Problemy rozpoznania i leczenia pierwotnej nadczynnosci przytarczyc--opis przypadku.

Primary hyperparathyroidism is systemic, polymorphic disease. Authors present a case of woman suffered from primary hyperparathyroidism misdiagnosed as disseminated neoplastic disease. There was shown a clinical picture complex, difficulties in diagnostic process, treatment and factors provided mistakes in therapy. The work lays stress on importance of routine testing of calcium in serum. It makes a contribution in diagnosis of hyperparathyroidism in symptomless or preclinical phase - before appearance metabolic and organ complications.

Plasma visfatin and tumor necrosis factor-alpha (TNF-α) levels in metabolic syndrome.

BACKGROUND: Experimental studies have shown that tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) downregulate visfatin gene expression in adipocytes. On the other hand, the induction of cytokine production by visfatin in leucocytes and monocytes has also been described. AIM: To assess the possible interrelation between plasma concentrations of visfatin and TNF-α and TNF soluble receptor in obese women fulfilling, or not, the criteria of metabolic syndrome (MS). METHODS: Ninety two obese women were included in the study. Metabolic syndrome, based on IDF criteria (2005) was diagnosed in 71 subjects (mean age 53 ± 9 years; body mass index 39.1 ± 5.6 kg/m(2), waist circumference 109.6 ± 11.4 cm). The remaining 21 formed the non-MS subgroup (mean age 52 ± 9 years, body mass index 36.3 ± 5.2 kg/m(2), waist circumference 104.7 ± 11.0 cm). Fourteen healthy normal weight women served as controls. In all subjects, body composition was assessed by the bioimpedance method. RESULTS: In the MS subgroup, but not in the non-MS subgroup, visfatin levels were significantly higher than in controls. We did not observe any significant difference in plasma concentrations of visfatin, TNF-α or sTNFRs between the MS subgroup and the non-MS subgroup. Only in the MS subgroup and in the combined analysis of all study subgroups did plasma visfatin concentrations correlate significantly with TNF-α levels (R = 0.31, p = 0.01, R = 0.21, p = 0.03; respectively). Additionally, in the MS subgroup there was a positive correlation between visfatin levels and insulin resistance (R = 0.53, p = 0.01). CONCLUSIONS: Our findings suggest that visfatin in metabolic syndrome should be regarded as a proinflammatory factor indirectly favouring the development of insulin resistance.

Randomized trial of single-dose versus divided-dose rabbit anti-thymocyte globulin induction in renal transplantation: an interim report.

BACKGROUND: The optimal dosing protocol for rabbit anti-thymocyte globulin (rATG) induction in renal transplantation has not been determined, but evidence exists that rATG infusion before renal allograft reperfusion improves early graft function. Infusing a large rATG dose over a short interval has not previously been evaluated for its effect on renal function and allograft nephropathy in a prospective, randomized comparison against conventional rATG induction. METHODS: Between April 20, 2004 and December 26, 2007 we enrolled renal transplant patients into a prospective, randomized, nonblinded trial of two rATG dosing protocols (single dose, 6 mg/kg vs. divided doses, 1.5 mg/kg every other day x 4; target enrollment=160) followed after 6 months by calcineurin-inhibitor withdrawal. Primary endpoints are renal function by calculated glomerular filtration rate (GFR) and chronic allograft nephropathy at protocol biopsy. We now present the early GFR data of all 160 patients and safety and efficacy data of the first 142 patients with 6 months follow up and before calcineurin inhibitor withdrawal (average follow up=23.3+/-11.6 months). RESULTS: There were no differences between groups in rATG-related adverse events, patient and graft survival, acute rejection, or chronic allograft nephropathy rate at 6 months. Calculated DeltaGFR (POD 1-4) was significantly better in the single-dose group (P=0.02), with a trend toward improved renal function from months 2 to 6 in recipients of deceased donor kidneys (P=0.08). CONCLUSIONS: This study demonstrates that administering 6 mg/kg of rATG over 24 hr is safe and is associated with improved early renal function compared with administering rATG in alternate-day doses.

Serum concentration of visfatin in obese women.

The aim of the present study was to determine serum concentrations of visfatin in obese women in comparison to normal-weight controls. Study subjects were 21 obese women without additional disease (age, 29.0+/-4.9 years; body mass index, 37.1+/-6.1 kg/m2) and 16 healthy, normal-weight women (age, 29.9+/-5.4 years; body mass index, 22.5+/-1.7 kg/m2). Body composition was measured by bioimpedance. Serum concentrations of visfatin were assayed with an enzyme-linked immunosorbent assay kit (Phoenix Pharmaceuticals, Burlingame, CA). Insulin was determined by radioimmunoassay and glucose by colorimetric method. Serum concentration of visfatin was significantly higher in obese women when compared to controls. Positive correlations between serum concentrations of visfatin and insulin in the obese group were found. In the control group, we observed positive correlations between serum concentrations of visfatin and glucose. In conclusion, the observed increase of visfatin in obesity may be a counterregulation preventing further glucose increase.

Idiopathic hypertrophic pachymeningitis - case report and literature review.

Idiopathic hypertrophic pachymeningitis (IHPM) is a rare pathological state, with still unclear aetiopathogenesis. We present a case of a 63-year-old woman with cranial variety of that disease. The manifestations of the disease included headaches, paresis of VI, IX, X nerves and cerebellar ataxia. The disease was diagnosed with magnetic resonance imaging (MRI) and histopathological assessment of the pachymeninx biopsy specimen. The MRI revealed significant thickening of the cranial base pachymeninx, compressing the pons and medulla oblongata. MRI examinations could be misinterpreted as extensive meningioma of the skull base. Dura mater biopsy revealed however inflammation with abundant lymphocytic infiltrations. Clinical improvement was obtained after the application of corticosteroids. We noted the subsidence of all symptoms of the disease, as well as radiological improvement, manifested through substantial regression of the described changes in the pachymeninx. The patient has been presented in the context of 65 cases of idiopathic hypertrophic pachymeningitis, described in the literature of English-speaking countries in the last five years. Recently, the importance of the autoimmunogenic background of IHPM has been underlined. In that respect IHPM has become an interdisciplinary problem. Its diagnosis and treatment requires not only radiologists, neurologists, pathomorphologists and neurosurgeons, but also specialists in internal medicine, including immunologists, allergologists and rheumatologists as well - in other words, physicians that rarely take part in the processes of diagnosing and treating intracranial pathologies.

[Cathether related blood stream infection in ICU patients with prolonged central venous catheterisation--cause and prevention]. / Przyczyny i zapobieganie zakazeniom u chorych po zalozeniu cewnika do duzych naczyn krwionosnych.

UNLABELLED: Colonization of the tip of the intravenous catheter is often observed in the ICU practice and can be the source of dangerous bacteriemia (CRBSI--catheter related bloodstream bacteraemia) and sepsis with multiorgan failure. There are many cases conected with bacterial colonization of the tip of the catheter in the ICU practice, which could be the source of dangerous bacteriemia--CRBSI (catheter related bloodstream bacteriemia) and sepsis with organs failure. MATERIAL AND METHODS: 105 patients with sepsis were examined, which clinical state pointed, that CVC was the source of infection. We removed the CVC in this patient, and its tip and patient's blood were examined microbiologically. In the case of positive result, the antibiogram was made. OBJECTIVE: Evaluation of colonisation and infections of central venous catheters and catheter related blood stream infections (CRBSI) in general ICU patients' and with identification of most frequent microorganisms and their antibiotic sensibility. Results. After examining of 105 samples in 37 (35, 24%) cases we did not culture bacteria. From the rest of 68 (64, 76%) samples we cultured 110 bacterial colonies. 8 of them were admitted to be contaminated samples. 60 tips of the catheter were used to proper analysis from which we isolated 102 bacterial colonies: 44 (43.1%) Gram positive cocci, 32 (31.5%) Enterobacteriaceae, 23 (22.5%) glucose non-fermentative gram-negative rods rods Gram negative non glucose fermentation and 3 (2.9%) fungi (C. albicans). We analized 60 blood samples that derived from patients with confirmed catheter colonisation. It was found that 8 blood samples indicated bacteriemia, but only in 2 cases isolated bacteria came from the CVC. Conclusions. (1) The majority of central venous catheters on ICU are colonized by pathogenic microorganisms. (2) Aerobic Gram positive and Gram negative bacteria are responsible for CVCs' infection. (3) Bacterial colonization of CVCs' is not very often the reason of CRBSI. (4) Prolonged use of central venous catheters needs careful prophylactic standards of an microbiological monitoring.