First observation of electrorheological plasmas.

We report the experimental discovery of "electrorheological (ER) complex plasmas," where the control of the interparticle interaction by an externally applied electric field is due to distortion of the Debye spheres that surround microparticles (dust) in a plasma. We show that interactions in ER plasmas under weak ac fields are mathematically equivalent to those in conventional ER fluids. Microgravity experiments, as well as molecular dynamics simulations, show a phase transition from an isotropic to an anisotropic (string) plasma state as the electric field is increased.

Force field inside the void in complex plasmas under microgravity conditions.

Observations of complex plasmas under microgravity conditions onboard the International Space Station performed with the Plasma-Kristall experiment-Nefedov facility are reported. A weak instability of the boundary between the central void (region free of microparticles) and the microparticle cloud is observed at low gas pressures. The instability leads to periodic injections of a relatively small number of particles into the void region (by analogy this effect is called the "trampoline effect"). The trajectories of injected particles are analyzed providing information on the force field inside the void. The experimental results are compared with theory which assumes that the most important forces inside the void are the electric and the ion drag forces. Good agreement is found clearly indicating that under conditions investigated the void formation is caused by the ion drag force.

Electrostatic modes in collisional complex plasmas under microgravity conditions.

A linear dispersion relation in a highly collisional complex plasma, including ion drift, was derived in the light of recent PKE-Nefedov wave experiment performed under microgravity conditions onboard the International Space Station. Two modifications of dust density waves with wave frequencies larger than the dust-neutral collision frequency were obtained. The relevance to the space observations was analyzed and a comparison of theory and observations was made for two different complex plasma domains formed by small and large microparticles. Good qualitative agreement is found between the measurements and the theoretical dispersion relations. This allows a determination of the basic complex plasma parameters.

[Neurological complications of renal transplant]. / Complicaciones neurológicas del trasplante renal.

Advances in surgical procedures and new immunosuppressor therapies have improved the outcome of renal grafts. However, these changes have been accompanied by infectious, neoplastic and neurologic complications. The purpose of this study was to determine the incidence of neurologic complications among 542 patients receiving a renal transplant (from living or cadaveric donors) at CEMIC between 1970 and 1996. Neurologic complications occurred in 43 patients (8%) as follows: 8 meningitis (1.5%), 8 acute confusional syndrome (1.5%), 7 encephalitis (1.3%), 7 cerebrovascular accidents (1.3%), 6 convulsions (1.1%), 3 tumors (0.5%), 3 femoral nerve lesion (0.5%), and 1 epidural lipomatosis (0.1%). Etiologic agents most commonly observed in meningitis were: Cryptococcus neoformans, Listeria monocytogenes and Mycobacterium tuberculosis. Major difficulties arose in the diagnosis of encephalitis. Diagnosis of the above complications required clinical astuteness and repeated bacteriologic, serologic and imaging studies.

Complicaciones neurológicas del trasplante renal. / [Neurological complications of renal transplant]

Advances in surgical procedures and new immunosuppressor therapies have improved the outcome of renal grafts. However, these changes have been accompanied by infectious, neoplastic and neurologic complications. The purpose of this study was to determine the incidence of neurologic complications among 542 patients receiving a renal transplant (from living or cadaveric donors) at CEMIC between 1970 and 1996. Neurologic complications occurred in 43 patients (8

) as follows: 8 meningitis (1.5

), 8 acute confusional syndrome (1.5

), 7 encephalitis (1.3

), 7 cerebrovascular accidents (1.3

), 6 convulsions (1.1

), 3 tumors (0.5

), 3 femoral nerve lesion (0.5

), and 1 epidural lipomatosis (0.1

). Etiologic agents most commonly observed in meningitis were: Cryptococcus neoformans, Listeria monocytogenes and Mycobacterium tuberculosis. Major difficulties arose in the diagnosis of encephalitis. Diagnosis of the above complications required clinical astuteness and repeated bacteriologic, serologic and imaging studies.

Energy supplementation in chronic hemodialysis patients with moderate and severe malnutrition.

OBJECTIVE: Prospectively evaluate the effect on the nutritional status of a glucose polymer as energy supplementation alone in chronic hemodialysis patients with moderate and severe malnutrition. MATERIAL AND METHODS: The nutritional status of 55 hemodialysis patients was assessed by using a score that included Iron binding capacity, albumin, cholesterol, body mass index, mid brachial circumference, arm muscle area, triceps skinfold, and clinical impression. Twenty-two of 27 patients (14 men and 8 women, mean age 43 +/- 15 years, time on dialysis 65 +/- 49 months) were classified as moderately or severely malnourished and were supplemented for 6 months with 100 g of glucose polymers per day (equivalent to 380 kcal or 1590 kJ) added to the usual food intake. The patients were reevaluated at 3 and 6 months. RESULTS: Only body weight, body mass index, triceps skinfold, and brachial circumference and clinical impression increased significantly at the end of the third month (P < .05) in the 22 patients. These results were confirmed at 6 months in 18 patients that completed the study. Mean body weight increase was 2.4 kg (range, .2 to 6.3 kg). The nutritional status, evaluated through the score, improved in only 4 patients at the end of the study. Few gastrointestinal side effects were observed. Triglycerides increased from 136 +/- 40 mg/dL to 235 +/- 120 mg/dL. Follow-up of the patients showed that fat mass (assessed by anthropometry) was maintained for 6 months after supplementation was discontinued. CONCLUSION: Energy supplementation alone in patients with moderate and severe malnutrition on chronic hemodialysis resulted in an increase in body weight, owing to an increase in body fat, but the nutritional status did not improve.

Effects of a copper-bearing intrauterine device on the ovarian function, body weight gain and pregnancy rate of nulliparous heifers.

A copper-bearing intrauterine device (IUD), designed to cause a slight distention of the uterus, was inserted through the cervix into each uterine horn of 230 heifers; an additional 230 heifers served as the control group. Blood was drawn at 0, 1, 2, 20 and 120 d for progesterone and testosterone assays. The heifers were checked twice daily for estrus and examined at 0, 60 and 120 d for weight gain. Thereafter they were bred over a 120-d period. The IUD caused anestrus in 98% of the heifers, with a daily weight gain 25.5 % higher than in the control heifers. Moreover, the device was 100% effective in preventing pregnancy. At 20 and 120 d after IUD insertion progesterone levels averaged 0.7 ng/ml, which was 4 to 5 times lower than in the control animals, suggesting a failure in ovulation or in corpus luteum (CL) formation due to the IUD. Simultaneously, testosterone values were increased up to 8 times in IUD-treated heifers, reaching a mean concentration of 163 pg/ml. Associated histological evaluations of the ovaries from UD-treated heifers revealed the presence of 2 or more cysts per ovary, with marked hyperthecosis in many antral follicles in which the granulosa cell layers were either thinned or lacking. The results suggest that the action of the copper-releasing IUD used in this study resulted in high contraceptive efficiency but also in disturbance of ovarian function. Our findings further raise the possibility of a cause and effect relationship between hyperandrogenism and the higher body weight gain observed in heifers treated with the IUD.

[Liver histology in chronic hemodialysis patients infected with hepatitis C virus]. / Histología hepática en pacientes hemodializados crónicos infectados con el virus de la hepatitis C.

Liver biopsies were analyzed in 21 patients with chronic renal failure (CRF) who tested positive for Hepatitis C Virus (HCV), using Elisa II and/ or PCR. The study included 14 men and 7 women, the average age being 41 years old (range: 20-65). The average span of time under dialysis was 64 months (range: 12-192). Hbs ag. was positive in six patients. Patients underwent biopsy for showing persistent rise of transaminase for more than 6 months. The modified Knodell Index was used to grade hepatic lesions. All biopsies showed chronic hepatitis, of which 2 were associated with cirrhosis. Eight patients were infected with mild chronic hepatitis, ten were infected with moderate chronic hepatitis, and only three patients had a severe lesion. Fibrosis was mild in 13 cases, moderate in 6, and 2 had cirrhosis. Chronic Hepatitis C characteristic lesions analysis showed lymphoid nodules in 6 cases (29%), ductal epithelium lesions in 7 (33%), and steatosis in 7 (33%). Chronic HCV infection in our patients seems to have histologic characteristics similar to those reported in HCV positive non CRF patients.

[Incidence, etiology and prognostic value of persistent significant proteinuria in kidney transplants]. / Incidencia, etiología y pronóstico de la proteinuria persistente significativa en el trasplante renal.

We investigated persistent significant proteinuria (PSP), defined as proteinuria > 1 gr/24 hours on three consecutive months, in renal allograft recipients. The clinical records of 273 patients (288 grafts) were reviewed and 236 grafts (178 live related, 58 cadaver donor) that functioned for at least 4 months (230 patients, 148 men and 82 women) were selected for analysis. The histological diagnoses of 226 grafts and 35 native kidneys were also reviewed. PSP was present in 67 grafts (28.4%); 43 of these grafts were studied histologically (transplant glomerulopathy (TxGPT) 19, idiopathic glomerulopathy (GP) 13, and chronic rejection 11). Patients with an idiopathic GP in the graft usually presented with the nephrotic syndrome (65%); this presentation was infrequent in patients with chronic rejection. The appearance of proteinuria was strongly associated with functional deterioration in grafts with chronic rejection and TxGPT; in grafts with PSP and a histological diagnosis of idiopathic GP, renal function was usually normal. Within grafts with PSP no statistically significant differences in actuarial survival (AS) could be established when the time of appearance or magnitude of PSP, the presence or absence of arterial hypertension, the immunosuppressive regimen, and the histological diagnosis were considered. Contrariwise, the difference in AS was highly significant (p < 0.0001) when grafts with and without PSP were compared. The former had an AS at 5 and 10 years of 74.6% and 55.7%, while in the case of the latter AS was 57.3% and 32.1%, respectively. In conclusion, in the present series 28.4% of grafts that functioned 4 months or more presented PSP. The most frequent glomerular lesion was TxGPT. The presence of PSP was a marker for poorer prognosis, since AS at 5 and 10 years was significantly less in this group.

[Nutritional status of patients on chronic hemodialysis]. / Estado nutricional de pacientes en hemodiálisis crónica.

The objective was to determine the nutritional status (NS) in a population undergoing chronic hemodialysis (CHD), and correlate it with dialysis dose and morbimortality. A total of 55 patients, 27 men and 28 women, aged 47 +/- 15 and with a history of CHD of 54.6 +/- 47.6 months were evaluated. NS was classified into: adequate, mild malnutrition, moderate malnutrition and severe malnutrition. A score based on usual laboratory data (total iron-binding capacity [TIBC], albumin and cholesterol), clinical evaluation and anthropometric measurements (body mass index [BMI], mid brachial circumference, tricipital fold [TF], mid brachial muscle circumference [MBMC]), was used. In addition, a 7-days' intake auto-registration plan was conducted, and protein catabolic rate (PCR) was determined. Calorie intake was of 27 +/- 13 kcal/kg/day and protein intake was of 1.2 +/- 0.5 g/kg/day. No correlation was found between the latter and PCR. 49.1% of patients had moderate to severe malnutrition, only 9 patients had an adequate NS. However anthropometric measurements showed that TF, MBMC and BMI were normal in 54.5%, 45%, and 72.7% of patients, respectively. No correlation was found between NS and age onset of CHD, sex, creatinine, dialysis dose (Kt/V x = 1.24 +/- 0.12), PCR and morbidity. A longer history of dialysis was associated with a worse NS (p < 0.01). In addition, NS significantly correlated with albumin (p < 0.01) and mortality (p < 0.05). The estimated death risk was 9.45 times higher in patients with moderate and severe malnutrition.

Anticuerpos anti-citoplasma de polimorfonuclear neutrófilo en granulomatosis de Wegener, en otras enfermedades autoinmunes y en pacientes hemodializados / Anticytoplasm antibodies of polymorphonuclear neutrophils in Wegener's granulomatosis, other autoimmune diseases and in patients under hemodialysis

Las vasculitis sistémicas son un grupo heterogénio de enfermedades caracterizadas por infiltración inflamatoria y necrosis de la pared vascular. Anticuerpos contra citoplasma de polimorfonuclear neutrófilo (ANCA-C y ANCA-P) fueron descriptos como marcadores serológicos de algunas de estas afecciones y de ciertos tipos de glomerulonefritis. La presencia de ANCA se investigó en el suero de 182 pacientes. En 16/17 con Granulomatosis de Wegener (G.W.) (critérios ACR) se encontró ANCA, 14 de ellos con imagen C (en 10 asociada a imagem P) y en los dos restantes, imagem P solamente (p < 0,001, comparando con los otros grupos estudiados). La presencia de estos anticorpos se asoció con la atividad clínica de la enfermedad (p, 0,01). El único paciente ANCA-C positivo fuera de este grupo tenía estonosis subglótica como única manifestación clínica con histología inespecífica, ANCA-P se encontró, además, en 6 por ciento de los casos con Enfermedades del Tejido Conectivo estudiados, y en 6/66 de la Unidad de Diálisis, lo cual sugiere que un mecanismo relacionado al ANCA puede ser el responsable de la nefropatía en aproximadamente el 10//de los pacientes en hemodiálisis crónica. Los resultados obtenidos indican que la investigación de ANCA puede ser un elemento de ayuda útil para el diagnóstico y monitoreo de la actividad clínica en la G.W

Anticuerpos anti-citoplasma de polimorfonuclear neutrófilo en granulomatosis de Wegener, en otras enfermedades autoinmunes y en pacientes hemodializados / Anticytoplasm antibodies of polymorphonuclear neutrophils in Wegeners granulomatosis, other autoimmune diseases and in patients under hemodialysis

Las vasculitis sistémicas son un grupo heterogénio de enfermedades caracterizadas por infiltración inflamatoria y necrosis de la pared vascular. Anticuerpos contra citoplasma de polimorfonuclear neutrófilo (ANCA-C y ANCA-P) fueron descriptos como marcadores serológicos de algunas de estas afecciones y de ciertos tipos de glomerulonefritis. La presencia de ANCA se investigó en el suero de 182 pacientes. En 16/17 con Granulomatosis de Wegener (G.W.) (critérios ACR) se encontró ANCA, 14 de ellos con imagen C (en 10 asociada a imagem P) y en los dos restantes, imagem P solamente (p < 0,001, comparando con los otros grupos estudiados). La presencia de estos anticorpos se asoció con la atividad clínica de la enfermedad (p, 0,01). El único paciente ANCA-C positivo fuera de este grupo tenía estonosis subglótica como única manifestación clínica con histología inespecífica, ANCA-P se encontró, además, en 6 por ciento de los casos con Enfermedades del Tejido Conectivo estudiados, y en 6/66 de la Unidad de Diálisis, lo cual sugiere que un mecanismo relacionado al ANCA puede ser el responsable de la nefropatía en aproximadamente el 10//de los pacientes en hemodiálisis crónica. Los resultados obtenidos indican que la investigación de ANCA puede ser un elemento de ayuda útil para el diagnóstico y monitoreo de la actividad clínica en la G.W (AU)

[Anticytoplasm antibodies of polymorphonuclear neutrophils in Wegener's granulomatosis, other autoimmune diseases, and in patients undergoing hemodialysis]. / Anticuerpos anti-citoplasma de polimorfonuclear neutrófilo en granulomatosis de Wegener, en otras enfermedades autoinmunes y en pacientes hemodializados.

Systemic vasculitis are an heterogeneous group of diseases characterized by inflammatory infiltration and necrosis of blood vessel walls. Antineutrophil cytoplasmic antibodies (ANCA) with different immunofluorescent patterns (C or P) have been described as serological markers of some of these diseases and some types of glomerulonephritis. The presence of ANCA by immunofluorescence on normal fixed polymorphonuclear neutrophils was investigated in 182 patients. Results are depicted in Table 1. ANCA was present in 16/17 (94%) patients with Wegener Granulomatosis (W.G.) (ACR criteria) (p < 0.001). In 14 out of the 16 (82%), the pattern was ANCA-C (associated in 10 with ANCA-P) and only ANCA-P was observed in the remaining two. The presence of ANCA was associated with active disease: 15/16 samples of active patients and 3/9 of inactive patients were ANCA positive (p < 0.01). Among the other groups, ANCA-C was detected in only one patient with isolated subglottal stenosis. The specificity of ANCA-C for W.G. was 99%. ANCA-P was also detected in 3/49 (6%) patients with connective tissue disorders and in 3/63 (5%) patients in chronic hemodialysis with exclusive or predominant renal disease of unknown etiology. Three additional ANCA positive patients with known diagnosis (2 W.G. and 1 Systemic Lupus Erythematosus) were also in hemodialysis in the same unit. Thus, an ANCA related mechanism may be involved in the pathogenesis of approximately 10% of cases undergoing this procedure. None of 45 sera submitted for the detection of antinuclear antibodies were ANCA positive. Detection of ANCA (especially C pattern) may be of help in the diagnosis of W.G. and in monitoring clinical activity of the disease.

Anticuerpos anti-citoplasma de polimorfonuclear neutrófilo en granulomatosis de Wegener, en otras enfermedades autoinmunes y en pacientes hemodializados. / [Anticytoplasm antibodies of polymorphonuclear neutrophils in Wegeners granulomatosis, other autoimmune diseases, and in patients undergoing hemodialysis]

Systemic vasculitis are an heterogeneous group of diseases characterized by inflammatory infiltration and necrosis of blood vessel walls. Antineutrophil cytoplasmic antibodies (ANCA) with different immunofluorescent patterns (C or P) have been described as serological markers of some of these diseases and some types of glomerulonephritis. The presence of ANCA by immunofluorescence on normal fixed polymorphonuclear neutrophils was investigated in 182 patients. Results are depicted in Table 1. ANCA was present in 16/17 (94

) patients with Wegener Granulomatosis (W.G.) (ACR criteria) (p < 0.001). In 14 out of the 16 (82

), the pattern was ANCA-C (associated in 10 with ANCA-P) and only ANCA-P was observed in the remaining two. The presence of ANCA was associated with active disease: 15/16 samples of active patients and 3/9 of inactive patients were ANCA positive (p < 0.01). Among the other groups, ANCA-C was detected in only one patient with isolated subglottal stenosis. The specificity of ANCA-C for W.G. was 99

. ANCA-P was also detected in 3/49 (6

) patients with connective tissue disorders and in 3/63 (5

) patients in chronic hemodialysis with exclusive or predominant renal disease of unknown etiology. Three additional ANCA positive patients with known diagnosis (2 W.G. and 1 Systemic Lupus Erythematosus) were also in hemodialysis in the same unit. Thus, an ANCA related mechanism may be involved in the pathogenesis of approximately 10

of cases undergoing this procedure. None of 45 sera submitted for the detection of antinuclear antibodies were ANCA positive. Detection of ANCA (especially C pattern) may be of help in the diagnosis of W.G. and in monitoring clinical activity of the disease.

[Cyclosporin interactions in kidney transplants]. / Interacciones de la ciclosporina en transplantados renales.

Treatment with Cyclosporine has resulted in improved allograft survival. Cyclosporine metabolism occurs in the liver via hepatic cytochrome P-450IIIA microsomal enzyme. Pharmacokinetic drug interactions usually involve drugs which induce or inhibit the cytochrome P-450 system. We reviewed the Medical Charts of 53 renal transplant recipients immunosuppressed with Cyclosporine between 1985 and 1991. We analysed the relationship between Cyclosporine concentration, its dose and the change induced by concomitant administration of different drugs. Until December 1988, Cyclosporine was measured by solid-phase radioimmunoassay (RIA) using a polyclonal antibody. This method measures Cyclosporine and some of its metabolites. Since January 1989, Cyclosporine was measured in whole blood by radioimmunoassay (RIA-Kit Sandimmun, Sandoz), which used a specific monoclonal antibody which binds Cyclosporine and a non-specific monoclonal antibody which binds Cyclosporine and its metabolites. The therapeutic range recommended by Sandoz in whole blood using the specific monoclonal antibody is 100 to 400 ng/ml. We present 3 cases of probable pharmacokinetic drug interactions with Cyclosporine. The first patient received concomitantly isoniazide (150 mg/day). Cyclosporine levels were between 600 and 2085 ng/ml despite the dose reduction from 10 to 1.5 mg/kg/day (Fig. 1). The dose reduction of isoniazide to 100 mg/day resulted in reduction of Cyclosporine levels. Until December 1988 with the polyclonal antibody the median was 320 ng/ml (range: 185 to 760 ng/ml; n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)

Interacciones de la ciclosporina en transplantados renales. / [Cyclosporin interactions in kidney transplants]

Treatment with Cyclosporine has resulted in improved allograft survival. Cyclosporine metabolism occurs in the liver via hepatic cytochrome P-450IIIA microsomal enzyme. Pharmacokinetic drug interactions usually involve drugs which induce or inhibit the cytochrome P-450 system. We reviewed the Medical Charts of 53 renal transplant recipients immunosuppressed with Cyclosporine between 1985 and 1991. We analysed the relationship between Cyclosporine concentration, its dose and the change induced by concomitant administration of different drugs. Until December 1988, Cyclosporine was measured by solid-phase radioimmunoassay (RIA) using a polyclonal antibody. This method measures Cyclosporine and some of its metabolites. Since January 1989, Cyclosporine was measured in whole blood by radioimmunoassay (RIA-Kit Sandimmun, Sandoz), which used a specific monoclonal antibody which binds Cyclosporine and a non-specific monoclonal antibody which binds Cyclosporine and its metabolites. The therapeutic range recommended by Sandoz in whole blood using the specific monoclonal antibody is 100 to 400 ng/ml. We present 3 cases of probable pharmacokinetic drug interactions with Cyclosporine. The first patient received concomitantly isoniazide (150 mg/day). Cyclosporine levels were between 600 and 2085 ng/ml despite the dose reduction from 10 to 1.5 mg/kg/day (Fig. 1). The dose reduction of isoniazide to 100 mg/day resulted in reduction of Cyclosporine levels. Until December 1988 with the polyclonal antibody the median was 320 ng/ml (range: 185 to 760 ng/ml; n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)

Interacciones de la ciclosporina en transplantados renales. / [Cyclosporin interactions in kidney transplants]

Treatment with Cyclosporine has resulted in improved allograft survival. Cyclosporine metabolism occurs in the liver via hepatic cytochrome P-450IIIA microsomal enzyme. Pharmacokinetic drug interactions usually involve drugs which induce or inhibit the cytochrome P-450 system. We reviewed the Medical Charts of 53 renal transplant recipients immunosuppressed with Cyclosporine between 1985 and 1991. We analysed the relationship between Cyclosporine concentration, its dose and the change induced by concomitant administration of different drugs. Until December 1988, Cyclosporine was measured by solid-phase radioimmunoassay (RIA) using a polyclonal antibody. This method measures Cyclosporine and some of its metabolites. Since January 1989, Cyclosporine was measured in whole blood by radioimmunoassay (RIA-Kit Sandimmun, Sandoz), which used a specific monoclonal antibody which binds Cyclosporine and a non-specific monoclonal antibody which binds Cyclosporine and its metabolites. The therapeutic range recommended by Sandoz in whole blood using the specific monoclonal antibody is 100 to 400 ng/ml. We present 3 cases of probable pharmacokinetic drug interactions with Cyclosporine. The first patient received concomitantly isoniazide (150 mg/day). Cyclosporine levels were between 600 and 2085 ng/ml despite the dose reduction from 10 to 1.5 mg/kg/day (Fig. 1). The dose reduction of isoniazide to 100 mg/day resulted in reduction of Cyclosporine levels. Until December 1988 with the polyclonal antibody the median was 320 ng/ml (range: 185 to 760 ng/ml; n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)