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Biomedical subjects

A Kaminski

Publications and source records attributed to A Kaminski.

At least 37 records · Page 2Linked to original sources
PubMed2003

Switching cyclosporine blood concentration monitoring from C0 to C2 in children late after liver transplantation.

BACKGROUND: Measurement of cyclospoprine (CsA) blood levels at 2 hours after oral administration (C(2)) has been proposed as a better measurement of trough level (C(0)) due to reduced intrapatient variability, acute rejection rate and renal toxicity. The aim of the present study was to assess whether there was any advantage to conversion from C(0) to C(2) CsA blood level monitoring in children late after liver transplantation. We reviewed the data from 44 children more than 1 year after liver transplantation. We measured the daily dose of CsA and the C(0) level before switching versus the daily dose and C(2) level at 6 months after conversion, in addition to the alanine aminotransferase (ALT) activity, creatinine blood concentration, and episodes of acute rejection. RESULTS: Conversion from C(0) to C(2) monitoring was not associated with a significant change in mean daily dose of CsA, mean concentration of creatinine, ALT activity or occurrence of rejection episodes. CONCLUSION: Switching from C(0) to C(2) monitoring did not seem to proffer any benefits for children late after liver transplantation.

Administration, Oral↗
PubMed2003

Acute coagulopathy after reperfusion of the liver graft in children correction with recombinant activated factor VII.

BACKGROUND: Several studies have proven that massive blood loss increases postoperative morbidity and mortality in liver graft recipients. Since we have successfully corrected coagulopathy preoperatively using an intravenous (IV) bolus of recombinant activated factor VII (rFVIIa) in 2 patients with fulminant liver failure, we observed that there was rapid reversal of preexisting advanced coagulopathy in another 40 patients with high risk for intraoperative bleeding by this treatment immediately before transplantation. Recently to control hemostasis we have administered rFVIIa also to patients presenting with acute coagulopathy and nonsurgical bleeding after graft reperfusion as described herein. MATERIALS AND METHODS: We have used rFVIIa in 7 children presenting with severe coagulopathy and nonsurgical bleeding after liver graft reperfusion. The dosage of rFVIIa ranged between 37 and 148 mcg/kg. An antifibrinolytic agent (aprotinin, tranexamic acid) was administered simultaneously. RESULTS: APTT before rFVIIa was 86.10 to 183 seconds, (mean, 132.1 +/- 39.88), after the bolus of rFVIIa 49.4 to 206.1 (mean, 112.7 +/- 58.53), and at the end of surgery 71.70 to 180 (mean, 110.3 +/- 40.98). INR after reperfusion was 1.82 to 3.91 (mean, 2.56 +/- 0.67), 1.03 to 1.92 (mean, 1.54 +/- 0.35) after rFVIIa, and 1.74 to 5.58 (mean, 2.64 +/- 1.35) at the end of surgery. Before rFVIIa administration intraoperative blood transfusions after graft reperfusion were 900 to 4200 mL of red blood cells (RBC) (0.82-5.4 total blood volume) and after reperfusion 0 to 1800 mL of RBC (0-2.5 TBV). No postoperative vascular complications were observed. CONCLUSIONS: A single dose of rFVIIa effectively reverses the severe coagulopathy developing after graft reperfusion, establishing effective hemostasis in liver transplant recipients without an increased risk of thrombotic complications.

Blood Coagulation Disorders↗
PubMed2003

Rapamycin in children after liver transplantation.

Experience with sirolimus (SRL) in pediatric liver transplantation (LTx) is limited. The aim of the study was to present our experience with SRL in this setting. During the last 2 years we administered SRL to 9 LTx: children in 3 due to chronic rejection and 6 due to impaired renal function. SRL was started at 2 months to 2.5 years after LTx. Target trough levels for tacrolimus for patients with chronic rejection was 8 to 10 ng/mL and SRL 10 to 12 ng/mL; for patients with impaired renal function, 4 to 6 ng/mL and 8 to 10 ng/mL respectively. For patients on only SRL and steroids the target level was 12 to 20 ng/mL. Our observation on SRL varied from 3 to 21 months, including liver function, renal function, and side effects. All patients are alive. In 3 patients with chronic rejection (ChR), follow-up biopsies showed no signs of ChR; they all normalized liver biochemistry. Independent of indication all improved their renal function. Follow-up GFR in 5 patients showed significant improvement in all. All patients showed elevated serum cholesterol values. SRL was discontinued in 3 patients due to elevation of liver enzymes in 1, persistently high serum cholesterol in 1, and repeated bouts of opportunistic infection in 1. Addition of SRL with reduced doses of tacrolimus or switching to SRL alone significantly improves renal function.

Acute Disease↗
PubMed2003

Liver retransplantation in children in Poland.

An average of 15% of patients require retransplantation due to irreversible liver graft failure due to primary graft nonfunction, chronic rejection, vascular and biliary complications, or infections. The survival of patients and grafts after retransplantation is inferior to that after primary transplantation. The purpose of the present study was to examine the incidence, indications, and outcome of retransplantation in children. In our center 169 liver transplantations had been performed in 154 patients, and 14 patients (9%) required 15 retransplantations: nine in the early postoperative period, five late after primary transplantation, and one late after the second transplantation. One-year patient survival after primary transplantation was 82%, but after early retransplantation it was 55%.

Child↗
PubMed2003

Anatomical alteration of the vascular tree observed during living related liver transplantation.

INTRODUCTION: The number of available cadaveric donor organs has reached a plateau. One current solution has been to increase number of living related liver transplantations. MATERIAL AND METHODS: Since October 1999 in the Department of General, Transplant and Liver Surgery, Medical University of Warsaw, 40 living related liver transplantation have been carried out. RESULTS: In 31 (77.5%) cases, a normal arterial supply was observed: the common hepatic artery arose from a celiac trunk. In two cases (5.0%), there was a partial arterial blood supply by the right accessory hepatic artery originating from the superior mesenteric artery. In two cases (5.0%), a right hepatic artery arose completely from the superior mesenteric artery (replaced artery). In one case (2.5%), a common hepatic artery originated from the superior mesenteric artery. In two cases (5.0%), an accessory left segmental artery originated from the left gastric artery. In two cases (5.0%), the function of an absent left hepatic artery was assumed by a replaced left hepatic artery originating from the left gastric artery. In two (5.0%) cases, there were two separate ducts draining the right hemiliver. There were two (5.0%) cases of an accessory duct draining segment IV, originating within the confluence of the right and left hepatic ducts. In one (2.5%) case, the common hepatic duct showed a trifurcation. CONCLUSION: During harvesting from a living donor knowledge of anatomical variants must be used to optomize the liver graft.

Family↗
PubMed2003

Bile duct variations in partial liver transplantations from living-related donors.

The aim of this paper was to present anatomic variations of bile ducts and their effect on the perioperative course of living-related donors in partial liver transplantations in children. Liver fragments for partial transplantation were harvested from 41 related donors. Segments II and III were harvested from 35 and segments II, III, and IV from 6 donors. During the procedure, cholangiography through cystic duct was performed revealing a normal anatomy of the bile ducts in 33 (80.5%) cases. The rest of the donors showed anatomic variations. There was only one case of complications related to the bile duct. The intraoperative diagnosis of anatomic variations allowed for safe partial liver harvesting.

Bile Ducts↗
PubMed2002

Burst fracture of the fifth lumbar vertebra: results of posterior internal fixation and transpedicular bone grafting.

Burst fractures of the fifth lumbar vertebra are rare, and there are only a few reports on this subject, which is characterised by its unique anatomical and biomechanical features. This retrospective analysis reports on ten patients whose fractures of L5 were stabilised with a short internal fixator in combination with a posterior fusion as well as transpedicular bone grafting. The average follow-up period was 22 months. Radiometric data were surveyed and compared to the functional results. The height of the fractured vertebra remained nearly unchanged throughout the course. Loss of lordosis of 4 degrees in the upper disc space and 4 degrees in the lower disc space were observed postoperatively. At the time of follow-up, the values of segmental lumbar lordosis were significantly below the preoperative level. The narrowing of the neural canal was reduced from 57% to 28% with the surgical intervention. However, there was no correlation between the functional and the radiological outcome. Neurological deficits were documented in two patients, which declined during the course. There were no severe postoperative complications. The results of the present study demonstrate that the described surgical procedure in fractures of the fifth lumbar vertebra does not promote an anatomic restoration of the fractured vertebra, nor of the segmental lordosis. However, the clinical results do not correlate with the radiological outcome. Nonoperative treatment with early mobilisation without external support seems to be the treatment of choice.

Adolescent↗
PubMed2002

Polaron percolation in diluted magnetic semiconductors.

We theoretically study the development of spontaneous magnetization in diluted magnetic semiconductors as arising from a percolation of bound magnetic polarons. Within the framework of a generalized percolation theory we derive analytic expressions for the Curie temperature and the magnetization in the limit of low carrier density, obtaining excellent quantitative agreement with Monte Carlo simulation results and good qualitative agreement with experimental results.

Journal Article↗
PubMed2002

Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor.

A change in 'symmetry' is often observed when matter undergoes a phase transition-the symmetry is said to be spontaneously broken. The transition made by underdoped high-transition-temperature (high-Tc) superconductors is unusual, in that it is not a mean-field transition as seen in other superconductors. Rather, there is a region in the phase diagram above the superconducting transition temperature Tc (where phase coherence and superconductivity begin) but below a characteristic temperature T* where a 'pseudogap' appears in the spectrum of electronic excitations. It is therefore important to establish if T* is just a cross-over temperature arising from fluctuations in the order parameter that will establish superconductivity at Tc (refs 3, 4), or if it marks a phase transition where symmetry is spontaneously broken. Here we report that, for a material in the pseudogap state, left-circularly polarized photons give a different photocurrent from right-circularly polarized photons. This shows that time-reversal symmetry is spontaneously broken below T*, which therefore corresponds to a phase transition.

Journal Article↗
PubMed2001

Electron energy relaxation in the presence of magnetic impurities.

We study inelastic electron-electron scattering mediated by the exchange interaction of electrons with magnetic impurities and find the kernel of the corresponding two-particle collision integral. In a wide region of parameters, the kernel K is proportional to the inverse square of the transferred energy, K proportional to J4/E2. The exchange constant J is renormalized due to the Kondo effect. At small energy transfers, the 1/E2 divergence is cut off; the cutoff energy is determined by the dynamics of the impurity spins. The obtained results may provide a quantitative explanation of the experiments of Pothier et al. [Phys. Rev. Lett. 79, 3490 (1997)] on anomalously strong energy relaxation in short metallic wires.

Journal Article↗
PubMed2001

Renormalization of spectral line shape and dispersion below Tc in Bi2Sr2CaCu2O8+delta.

Angle-resolved photoemission data in the superconducting state of Bi2Sr2CaCu2O8+delta show a kink in the dispersion along the zone diagonal, which is related via a Kramers-Krönig analysis to a drop in the low energy scattering rate. As one moves towards (pi,0), this kink evolves into a spectral dip. The occurrence of these anomalies in the dispersion and line shape throughout the zone indicates the presence of a new energy scale in the superconducting state.

Journal Article↗
PubMed2001

Jejunal feeding, even when instituted late, improves outcomes in patients with severe pancreatitis and peritonitis.

This study assessed the feasibility and effectiveness of jejunal feeding (JF) after surgery due to secondary peritonitis or failed conservative therapy of severe pancreatitis. Of 60 patients, 30 were randomly assigned to receive postoperative JF and the remaining 30 constituted the control group. Acute Physiology and Chronic Health Evaluation II, nutritional intake, systemic inflammatory response syndrome, and outcomes were measured. Patients in JF group received the daily mean of 1294.6 (362.6) kcal including 830.6 (372.7.0) kcal enterally, versus 472.8 (155.8) kcal daily in the control group (P < 0.0001). There were fewer complications in the JF patients, with no significant difference; length of stay in the intensive care unit and in the hospital did not differ. The frequency of systemic inflammatory response syndrome was similar in both groups, but outcomes differed. The first surgical intervention resulted in 3.3% of relaparotomies in JF patients, caused by unresolved peritonitis, versus 26.7% in the control subjects (P = 0.03). Recovery of bowel transit took significantly less time in the JF patients (mean: 54.6 h versus 76.8 h in control subjects, P = 0.01). JF resulted in 3.3% mortality as opposed to 23.3% in the control group (P = 0.05). In conclusion, JF is feasible and effective in postoperative treatment of patients due to secondary peritonitis or severe pancreatitis. Improved bowel and peritoneal function could be the main impact of JF.

Adolescent↗
PubMed2000

Fermi surface of Bi2Sr2CaCu2O8

We study the Fermi surface of Bi2Sr2CaCu2O8 using angle resolved photoemission spectroscopy (ARPES) with a momentum resolution of approximately 0.01 of the Brillouin zone. We show that, contrary to recent suggestions, the ARPES derived Fermi surface is a large hole barrel centered at (pi,pi), independent of the incident photon energy. We caution that the photon energy and k dependence of the matrix elements, if not properly accounted for, can lead to misinterpretation of ARPES intensities.

Journal Article↗
PubMed2000

Quasiparticles in the superconducting state of Bi(2)Sr(2)CaCu(2)O(8+delta)

Recent improvements in momentum resolution lead to qualitatively new angle-resolved photoemission spectroscopy results on the spectra of Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi2212) along the (pi,pi) direction, where there is a node in the superconducting gap. We now see the intrinsic line shape, which indicates the presence of true quasiparticles at all Fermi momenta in the superconducting state, and lack thereof in the normal state. The region of momentum space probed here is relevant for charge transport, motivating a comparison of our results to conductivity measurements by infrared reflectivity.

Journal Article↗
PubMed1999

Amnion allografts prepared in the Central Tissue Bank in Warsaw.

Applications of allogenic amnion grafts range from wound dressing of severe burns, dermabrasions and lower extremity ulcer treatments to plastic surgery, laryngology and ophthalmology. The aim of the present study was to elaborate the method of processing, preservation and sterilization of human amnion allografts prepared as wound dressing used mainly for burned patients. During the amniotic sac processing (after separation of chorion) special attention was paid to ensure that the epithelial side of amnion is placed directly on polyester net used as a support. After application on the wound, the epithelial side with the basement membrane is facing outwards; this will promote migration, attachment and spreading of the host cells encouraging epithelialization. Human amnion allografts were preserved by lyophilization or deep-freezing and subsequently radiation-sterilized with a dose of 35 kGy. It has been observed, however, that lyophilized irradiated allografts are resorbed within a few days, while frozen irradiated ones better adhere to wound and persist even 3 weeks after grafting, therefore, it has been decided to preserve amnion by deep-freezing. Since the beginning of 1998 over 400 preserved radiation-sterilized amnion allografts (with a total surface area over 40,000 cm2) have been prepared at the Central Tissue Bank in Warsaw and distributed to clinics and hospitals throughout the country.

Amnion↗
PubMed1998

The polypyrimidine tract binding protein (PTB) requirement for internal initiation of translation of cardiovirus RNAs is conditional rather than absolute.

Picornavirus RNAs are translated by an unusual mechanism of internal ribosome entry that requires a substantial segment of the viral 5'-untranslated region, generally known as the internal ribosome entry segment (IRES), and in some circumstances may require cellular trans-acting proteins, particularly polypyrimidine tract binding protein (PTB). It is shown here that for encephalomyocarditis virus (EMCV), the PTB dependence of IRES function in vitro is determined partly by the nature of the reporter cistron, and more especially by the size of an A-rich bulge in the IRES. With a wild-type EMCV IRES (which has a bulge of 6 As), translation is effectively independent of PTB provided the IRES is driving the synthesis of EMCV viral polyprotein. With an enlarged (7A) bulge and heterologous reporters, translation is highly dependent on PTB. Intermediate levels of PTB dependence are seen with a 7A bulge IRES driving viral polyprotein synthesis or a wild-type (6A) bulge IRES linked to a heterologous reporter. None of these parameters influenced the binding of PTB to the high-affinity site in the IRES. These results argue that PTB is not an essential and universal internal initiation factor, but, rather, that when it is required, its binding to the IRES helps to maintain the appropriate higher-order structure and to reverse distortions caused, for example, by an enlarged A-rich bulge.

Adenine Nucleotides↗