Roland Walter

The nitric oxide synthase cofactor tetrahydrobiopterin reduces allograft ischemia-reperfusion injury after lung transplantation.

OBJECTIVEnExogenous nitric oxide reduces ischemia-reperfusion injury after solid organ transplantation. Tetrahydrobiopterin, an essential cofactor for nitric oxide synthases, may restore impaired endothelium-dependent nitric oxide synthesis. We evaluated whether tetrahydrobiopterin administration to the recipient attenuates lung reperfusion injury after transplantation in swine.nnnMETHODSnUnilateral left lung transplantation was performed in 15 weight-matched pigs (24-31 kg). Donor lungs were flushed with 1.5 L cold (1 degrees C) low-potassium-dextran solution and preserved for 20 hours. Group I animals served as controls. Group II and III animals were treated with a bolus of tetrahydrobiopterin (20 mg/kg). In addition, in group III a continuous infusion of tetrahydrobiopterin (10 mg/kg per hour over 5 hours) was given. One hour after reperfusion, the recipient right lung was occluded. Cyclic guanosine monophosphate levels were measured in the pulmonary venous and central venous blood. Extravascular lung water index, hemodynamic variables, lipid peroxidation, and neutrophil migration to the allograft were assessed.nnnRESULTSnIn group III a significant reduction of extravascular lung water was noted in comparison with the controls (P =.0047). Lipid peroxidation in lung allograft tissue was significantly reduced in group II (P =.0021) and group III ( P =. 0077) in comparison with group I. Pulmonary venous levels of cyclic guanosine monophosphate increased up to 23 +/- 1 pmol/mL at 5 hours in group II and up to 40 +/- 1 pmol/mL in group III (group I, 4.1 +/- 0.5 pmol/mL [I vs III]; P <.001), whereas central venous levels of cyclic guanosine monophosphate were unchanged in all groups.nnnCONCLUSIONnTetrahydrobiopterin administration during lung allograft reperfusion may reduce posttransplantation lung edema and oxygen-derived free radical injury in the graft. This effect is mediated by local enhancement of the nitric oxide/cyclic guanosine monophosphate pathway.

Commercial taxane formulations induce stomatocytosis and increase blood viscosity.

Taxanes are antineoplastic drugs which have cardiovascular side effects of unknown mechanism. We investigated their influence on blood viscosity and erythrocyte morphology. Whole blood was incubated in vitro with increasing concentrations of Taxol®, Taxotere®, paclitaxel (0u2003–u2003100u2003μM) and the vehicles Cremophor‐EL and Tween 80 (0u2003–u20035%u2003vol) for 1u2003h at 37°C. Plasma and whole blood viscosity (Haematocrit 45%) were measured and erythrocyte morphology was assessed on glutaraldehyde‐fixed cells. The same investigations were performed in seven patients before and after a Taxol®‐infusion. Taxol® and Taxotere® induced a dose‐ and time‐dependent stomatocytic shape transformation of erythrocytes. Paclitaxel alone had no effect, but the vehicles cremophor‐EL and Tween 80, used in Taxol® and Taxotere®, respectively, induced a comparable degree of stomatocytosis. This suggests a preferential intercalation of these substances into the inner hemileaflet of the membrane lipid bilayer. Associated with this shape change a dose‐dependent increase in plasma and whole blood viscosity was observed. Neither shape nor viscosity changes were reversible upon removal of the agents. After the infusion of 130u2003–u2003300u2003mg Taxol® in patients a slight shift towards stomatocytosis and an increase in whole blood viscosity at high shear rate from 5.09±0.30 to 5.44±0.38u2003mPa.s (P<0.05) were confirmed. Commercial taxane drug formulations induce stomatocytosis and increase blood viscosity, which is due to their formulation vehicles. These findings may contribute to the understanding of the cardiovascular side effects of these drugs.

Drotrecogin alfa (activated) for the treatment of meningococcal purpura fulminans

wards normalization. Similarly, the extent of skin necrosis declined markedly, and in three patients full recovery was achieved. One patient lost three toes on both feet, but all other digits recovered fully. No complications that could be attributed to an adverse effect of drotrecogin alfa (activated) were noted. No bleeding events were observed under strict control of the platelet count and a limited dose of heparin. Patients 3 and 4 received 6 platelet concentrates to maintain platelet count above 30×103/μl. There was no need for freshfrozen plasma or red blood cell transfusions. The median ICU stay was 6 days (range 2–9 days) and hospital stay was 18 days (range 14–28 days). The excellent outcome in all cases despite septic shock with purpura fulminans and in two patients platelets counts below 30×103/μl on ICU admission underlines the potential advantage of drotrecogin alfa (activated) for the treatment of severe meningococcal infection. We suggest that a platelet count below 30×103/μl should not be an absolute exclusion criteria for treatment with drotrecogin alfa, provided that they can be kept above this limit during drotrecogin alfa (activated) substitution. References

Influence of nitrovasodilators and endothelin-1 on rheology of human blood in vitro

The shear stress of flowing blood profoundly influences the release of endothelium‐dependent vasodilative and constrictive factors. Conversely, the influence of these mediators such as nitric oxide (NO) or endothelin‐1 (ET‐1) on blood rheology remains elusive. In the present study the influence of nitrovasodilators and ET‐1 on red blood cell (RBC) shape and whole blood viscosity were investigated. Incubation of whole blood with sodium‐nitroprusside (SNP, 10−5–10−2u2003M), glyceryl trinitrate (GTN, 0.0001–0.1u2003mgu2003mL−1), S‐nitroso‐N‐acetylpenicillamine (SNAP, 10−6–10−3u2003M), and the active metabolite of molsidomine (SIN‐1, 10−6–10−3u2003M), but not molsidomine (10−6–10−3u2003M), resulted in significantly increased amounts of methaemoglobin, indicating a relevant interaction with RBCs. Treatment with SNP at 10−2u2003M induced a marked echinocytosis (morphological index: 2.23±0.98 vs −0.17±0.10; P<0.001) and increased blood viscosity (haematocrit 45%) at a high shear rate of 94.5u2003s−1 (6.46±0.60 vs 5.07±0.35u2003mPa·s; P<0.01) and a low shear rate of 0.1u2003s−1 (88.6±36.8 vs 42.1±11.7u2003mPa·s; P<0.01). Echinocytosis was probably due to cyanide accumulation. SIN‐1 at 10−3u2003M slightly decreased high shear viscosity (4.88±0.28 vs 4.95±0.30u2003mPa·s; P<0.05). SNAP at 10−3u2003M slightly increased both high (5.14±0.23 vs 5.05±0.24u2003mPa·s; P<0.01) and low shear (53.9±7.2 vs 51.2±5.9u2003mPa·s; P<0.05) viscosity. Molsidomine and GTN failed to influence whole blood viscosity. ET‐1 (10−9–10−6u2003M) had no effect on RBC shape and viscosity. We conclude that the most important modulators of vascular tone, NO and ET‐1, do not affect RBC shape and blood viscosity, which is important from both a physiological and a pharmacological point of view.

Primary Pleomorphic Adenoma of the External Auditory Canal Diagnosed by Fine Needle Aspiration Cytology

BACKGROUNDnPleomorphic adenoma (PA) arising in the external auditory canal (EAC) is a very rare neoplasm, thought to be derived from ceruminous glands.nnnCASEnA 43-year-old male presented with a slowly growing mass in the right EAC. Clinical and radiologic examinations showed a well-circumscribed tumor limited to the EAC, without a connection to the parotid gland. Fine needle aspiration cytology (FNAC) revealed the typical cytologic findings of PA. The diagnosis was confirmed by histologic examination.nnnCONCLUSIONnThis case illustrates that together with clinical and radiologic findings, primary PA of the EAC can confidently be diagnosed by FNAC.

Untroubled musical judgement of a performing organist during early epileptic seizure of the right temporal lobe.

The case of a professional musician with a right temporal lobe epilepsy is presented. Whilst playing an organ concert (John Stanleys Voluntary VIII, Op. 5), he suffered a complex partial seizure. The recorded concert performance (with the seizure) was analysed and compared with other available exercise records and with the composition. The musical analysis of the seizure-induced variations reveals that at the beginning of the seizure, the left hand started to become unprecise in time and deviated from the score, whereas the right hand remained faultless at this time. With increasing duration of the seizure discharge, the dissociation of both hands from the score increased but the right hand compensated for the errors of the left hand in a musically meaningful way, i.e. with the aim to compensate for the seizure-induced errors of the left hand. The case illustrates untroubled musical judgement during epileptic activity in the right temporal lobe at the beginning of the seizure. Whereas the temporal formation of the performance was markedly impaired, the ability of improvisation-in the sense of a perfect musical solution to errors of the left hand-remained intact.

Establishment and characterization of an arsenic‐sensitive monoblastic leukaemia cell line (SigM5)

Few human monoblastic cell lines have been characterized to date. We have established the SigM5 cell line from a patient with acute monoblastic leukaemia (FAB M5a). Original leukaemic cells had a karyotype of 47,XY,+8, whereas the cell line showed a stemline clone of 81,XX,Y,Y,1,4,6,7,+8,+8,9,10,10,11,13,16,19[cp], with a minor sideline also present. Cytochemical staining was strongly positive with α‐naphthylbutyrate acetate esterase, particulate positive with Sudan black and weakly positive for myeloperoxidase. Cells were positive for CD13, CD15, CD18, CD23, CD33, CD38, CD45, CD68 and myeloperoxidase. CD14 expression was 3–15%. SigM5 constitutively secreted interleukin (IL)‐2, IL‐8, IL‐10, tumour necrosis factor (TNF)‐α, ferritin, lysozyme, N‐elastase and neopterin upon stimulation with interferon (IFN)‐γ. Cells expressed the proinflammatory mediator macrophage migration inhibitory factor (MIF). All NADPH oxidase subunits were constitutively present, but nitroblue tetrazolium reduction was only detectable upon activation with IFN‐γ. SigM5 monoblasts were sensitive to arsenic trioxide (As2O3) previously not described to induce apoptosis in monoblastic cells. Differing considerably in morphology, immunophenotype and sensitivity to arsenics from the widely used cell lines U937, HL‐60 and THP‐1, SigM5 is a new monoblastic cell line useful for studying leukaemogenesis, monocyte differentiation and tumour cell susceptibility to arsenic compounds.

Impairment of blood rheology by cholestatic jaundice in human beings

Bilirubin and bile acids may affect erythrocytes. We investigated blood viscosity and erythrocyte structure in patients with cholestatic jaundice ex vivo and studied the short-term effects of bilirubin and bile acids in vitro. Seventeen patients with cholestatic jaundice and controls were studied. Whole-blood viscosity (adjusted hematocrit 45%) at high (94.5 sec(-1)) and low (0.1 sec(-1)) shear rate and plasma viscosity were measured. Erythrocyte structure was assessed in wet preparations of fixed cells. In vitro whole blood was incubated with increasing concentrations of bilirubin (83% conjugated) and bile acids (cholic, lithocholic, deoxycholic, and chenodeoxycholic acid) and the abovementioned investigations were performed. In patients we observed increased whole-blood viscosity at high shear rate (5.82 +/- 0.69 vs 5.04+/- 0.27 mPa. sec, P =.0001), plasma viscosity (1.48 +/- 0.22 vs. 1.23 +/- 0.07 mPa. sec, P =.0004), and fibrinogen level (4.70 +/- 0.98 g/L vs 2.63 +/- 0.21 g/L, P < 0.001) were observed. The incubation of normal erythrocytes in patients plasma confirmed an increase in blood viscosity at high shear rate. Erythrocytes from patients with jaundice demonstrated a slight degree of stomatocytic shape transformation (P <.0001). In vitro, bilirubin did not affect erythrocyte shape. Cholic and lithocholic acids caused a slight stomatocytic shape transformation, whereas deoxycholic acid and chenodeoxycholic acid influenced neither blood viscosity nor erythrocyte structure. Patients with cholestatic jaundice have increased whole-blood and plasma viscosity and slightly altered red blood cell shape, possibly the result of a combination of increased levels of bilirubin and bile acids plus an acute-phase reaction.