US Guidelines for immune tolerance induction in patients with haemophilia a and inhibitors.

INTRODUCTION: The development of anti-factor VIII (FVIII) antibodies (inhibitors) is the most serious treatment-related complication in patients with hemophilia A, rendering standard replacement therapy ineffective, heightening the risk for uncontrollable bleeding and morbidity, decreasing quality of life, and increasing healthcare costs. AIM: Formulate evidence-based guidelines for optimizing immune tolerance induction (ITI) in patients with hemophilia A and inhibitors. METHODS: Results from the International ITI study and other available evidence were used to develop guidelines for ITI. RESULTS: Predictors of ITI success were identified and recommendations made for ITI with regard to candidates, timing, product, regimen, monitoring, defining success, concurrent immunomodulation, duration of treatment, and bleed management before and during ITI. CONCLUSION: Evidence-based recommendations to guide treatment decisions may increase the likelihood of successful inhibitor eradication and the induction of FVIII tolerance in patients with hemophilia A who develop inhibitory antibodies.

Function of the sexually dimorphic ear of the American bullfrog, Rana catesbeiana: brief review and new insight.

The dimorphic ear of the bullfrog, Rana catesbeiana, has long been enigmatic. The male's tympanic membrane (TM) area approximates twice the area of the female's; however, similar size differences in the area of the columellar footplate were not observed between the sexes. Hence, the male's hearing is expected to be more sensitive than the female's but this is not the case. Asking what offsets the advantage of the large TM, we applied a series of experiments to the auditory system. Male and female audiograms based on stimulation with airborne sound and on both multi-unit responses from the brain and alternating cochlear potentials ('microphonics') showed equal sensitivity and a small difference in frequency response; at low frequencies the male was more sensitive than the female. Amputating the columella and stimulating the stump with mechanical vibration showed that for an equal microphonic response, the male's footplate vibrated with lower amplitude than the female's footplate. Mechanically stimulating the TM of the intact ear replicated this result, excluding the involvement of the mechanical lever. The TM of the male weighs five times the TM of the female, and artificial loading of the TM of either sex greatly reduced the ear's sensitivity. Hence, the male's excessive area ratio (TM to columellar footplate) is offset by the heavier cartilage cushion on the male's TM, damping the TM's response to sound. This is corroborated by experimentally artificially loading the TM. The product of area ratio and footplate vibration amplitude would result in similar stimulation of the inner ear in the two sexes.

Veno-occlusive disease of the liver in children with solid tumors undergoing autologous hematopoietic progenitor cell transplantation: a high incidence in patients with neuroblastoma.

We retrospectively analyzed the incidence and risk factors for veno-occlusive disease (VOD) in 83 consecutive children with solid tumors, who underwent autologous blood or bone marrow (BM) transplantation at UCSF between 1992 and 2000. Forty-one patients were diagnosed with neuroblastoma and 42 had another solid tumor (Ewing's sarcoma, soft tissue sarcomas, germ cell tumors, etc). Patients with neuroblastoma were more likely than patients with other solid tumors (ST) to be < or =7 years of age, to have a decreased serum albumin level, and to have received abdominal radiation and surgery prior to transplant. Patients with neuroblastoma received a different conditioning regimen and a purged stem cell product. Twenty patients (24%) developed VOD. VOD was self-limited in 15 (75%) patients and severe in five (25%) patients. Univariate analysis identified the following risk factors for VOD: diagnosis of neuroblastoma (odds ratio 6.1, P < 0.01), abdominal radiation (odds ratio 4.1, P < 0.01), abdominal surgery (odds ratio 4.1, P < 0.01), and age < or =7 years of age (odds ratio 3.3, P = 0.02). Disease status at transplant, intensity of previous chemotherapy, conditioning regimen, progenitor cell source, ALT, AST, albumin level, renal function prior to transplant, or use of amphotericin, growth-factor or heparin during transplant, did not affect the incidence of VOD. On multivariate analysis, only the diagnosis of neuroblastoma remained significant (odds ratio 7.8, P = 0.03). Larger studies of patients with neuroblastoma are necessary in order to confirm our findings and better define the risk factors for VOD development in neuroblastoma patients.

Definition of a critical T cell threshold for prevention of GVHD after HLA non-identical PBPC transplantation in children.

The aim of this study was to reduce the rate of graft failure after HLA non-identical stem cell transplantation by using G-CSF mobilized CD34+ peripheral blood progenitor cells (PBPC), either in combination with bone marrow or as single grafts. To prevent GVHD, PBPC were highly purified, resulting in a 5 to 6 log T cell depletion. In additon to T cell depletion no further GVHD prophylaxis was used. We transplanted 23 pediatric patients with life-threatening malignant or non-malignant hematological disorders, who had no available matched donor. Engraftment was obtained in 18 of 21 evaluable patients. Five patients developed acute GVHD of grade II and III, which became chronic in four cases and was fatal in four. The use of highly purified PBPC allowed the exact quantification of residual T cells in the grafts and a strict correlation between the residual T cell load and the development of GVHD was observed: patients with GVHD had received numbers of T cells between 8 and 20 x 104/kg, whereas patients without GVHD were grafted with T cell numbers ranging from 0.7 to 6.0 x 104/kg. We therefore clearly demonstrate that a residual T cell content of <5 x 104/kg is safe for prevention of GVHD after HLA non-identical PBPC transplantation in children.

Factors modulating the blood feeding behavior and the electrophysiological responses of labral apical chemoreceptors to adenine nucleotides in the mosquito Aedes aegypti (Culicidae).

The feeding of Aedes aegypti (L.) on blood is induced by the presence of phagostimulants: adenine nucleotides. Three chemoreceptive cells in the labral apical sensilla can distinguish the presence of adenine nucleotides depending on the other stimulus components. This work aims at correlating the sensory information arising from the labral apical sensilla with the feeding behavior in response to the same stimuli. The saline stimulating solution, containing adenine nucleotides, is modulated by changing one of the following components: salt concentration, buffer or pH. Cell 3 that responds to NaCl in a dose dependent manner seems to have another unique modality. The response of this cell is unaffected by ATP when the stimulating solution is NaCl buffered by NaHCO(3). It responds at a higher spike frequency to the presence of ATP in a NaCl solution without NaHCO(3). Thus in the presence of ATP Cell 3 detects whether the NaCl solution is buffered by NaHCO(3). Both the blood feeding response and the sensory information from Cell 2 (which responds at high spike frequencies to the presence of ATP) are modulated by pH in a similar way. Both responses present a bi-modal response, with a major peak at pH 4.0 and a moderate peak at the most alkaline pH value tested.

Sensitivity of the mosquito Aedes aegypti (Culicidae) labral apical chemoreceptors to blood plasma components.

The phagostimulants from the cellular fraction of blood induce gorging of Aedes aegypti (L.), and this process is enhanced by some plasma components. This project examines the responses of the labral apical chemoreceptors to plasma components enhancing phagostimulation. From the electrophysiological responses of the labral apical chemoreceptors four cells were identified by the waveform of their action potentials. Three of the cells (Cell 2, Cell 3 and Cell 4) responded in a dose dependent manner to NaCl. The responses of Cell 2 and Cell 3 to NaCl concentrations from 1 to 500 mmol/l can be described by a logarithmic equation. The response of Cell 2 to 150 mmol/l NaCl is modulated when a buffer is added. The magnitude of the modulation of the response is determined by the nature of the buffer: NaHCO(3) inhibits while Na(2)HPO(4) enhances the response. High osmotic pressure inhibits the response of Cell 4, regardless of how it is achieved. Cell 4 responds with a high frequency to the presence of L-alanine, the C-terminal amino acid of albumin, but shows a reduced response to the same concentration of albumin. From these results it can be concluded that labral apical chemoreceptors of A. aegypti are capable of detecting the plasma components involved in blood recognition.

Sensitivity of the mosquito Aedes aegypti (Culicidae) labral apical chemoreceptors to phagostimulants.

The feeding of Aedes aegypti (L.) on blood and nectar is induced by phagostimulants: adenine nucleotides and sugars respectively. This work examines the responses of the four chemoreceptor cells in the labral apical sensilla to these phagostimulants. The apical chemoreceptors can detect the presence of adenine nucleotides. This part of the response is in good agreement with the gorging behavior. The output of the chemoreceptors cannot distinguish among different adenine nucleotides or among their concentrations (0.01-1 mmol/l), whereas gorging behavior is affected by the identity of adenine nucleotides and by their concentrations. Hence the gorging behavior cannot be driven by the output of these chemoreceptors alone. To the presence of adenine nucleotides Cell 2 was the only cell that responded with high frequencies, while the response of Cell 4 was almost abolished. The response of Cell 2 to ATP depended on the mosquito's physiological state. This dependence accorded well with the gorging behavior; Cell 2 responded with a higher frequency to ATP in the gorging state, than when not in a gorging state. The responses to sucrose and fructose constituted the only case recorded in which all these chemoreceptors failed to respond. This depression of response implies that other chemoreceptors must be present as sugar detectors.

Nephrotic syndrome, hypertension, and adrenal failure in atypical Cockayne syndrome.

This report describes a boy with an atypical severe from of Cockayne syndrome type II manifesting in infancy. He developed nephrotic syndrome at the age of 4.7 years and a hypertensive crisis with hemiparesis at 5.4 years. Renal biopsy revealed focal segmental glomerulosclerosis, which was confirmed at autopsy. Adrenocortical failure was also present. The course was characterized by frequent infections and an episode of myocarditis. The boy died at the age of 6.0 years after rapid neurological deterioration accompanied by renal insufficiency. Autopsy disclosed cerebral leukodystrophy compatible with Cockayne syndrome.

Mortality trends in pediatric patients with chronic renal failure.

Mortality trends were analyzed in 441 children and adolescents with chronic renal failure (CRF) observed over a 24-year period before and after institution of renal replacement therapy (RRT). A total of 93 patients died. Overall mortality rate (MR) per 100 patient years decreased from 6.6 in 1969-1978 to 2.5 in 1979-1988 and increased slightly to 2.9 in 1989-1992. The fall involved all four modes of treatment: conservative, hemodialysis (HD), continuous peritoneal dialysis (CPD), and transplantation (TX). From 1979-1988 to 1989-1992 MR on conservative and on dialysis treatment changed only slightly and was similar on HD and CPD. An alarming rise in MR was noted after TX in 1989-1992, mainly due to malignant tumors. In 44 patients who died on conservative treatment, the reasons for non-acceptance for RRT were analyzed: in 22 multi-morbidity was the main reason, usually because of a congenital neurological disorder. Some patients died from advanced uremia or unexpected events after the decision to institute RRT. Our experience demonstrates a persistent mortality in pediatric patients with CRF, which in recent years is primarily ascribed to congenital multi-morbid conditions which make RRT unfeasible, infections on dialysis treatment, and malignancies after TX.

[Is there a clinical indication for the determination of atrial natriuretic peptide?]. / Gibt es eine klinische Indikation für die Bestimmung des atrialen natriuretischen Peptids?

Atrial natriuretic peptide (ANP) is a hormone produced, stored and secreted by atrial muscle cells. By its natriuretic, diuretic and blood pressure lowering activities ANP is possibly an endogenic antagonist for the sodium-retaining, vasopressor renin-angiotensin-aldosterone system (RAAS). In diseases associated with increased intravascular volume ANP plasma concentrations have been found elevated, in those associated with decreased volume ANP has been found decreased. In essential hypertension and chronic heart or renal failure diagnostic conclusions may be drawn from the ANP plasma concentration. This review summarizes the present knowledge about physiology and pathophysiology of ANP and values in addition the diagnostic power of ANP measurements for clinical routine in hypertension, heart and renal failure.

Changing pattern of chronic renal failure and renal replacement therapy in children and adolescents: a 20-year single centre study.

We analysed the demographic data, clinical course and survival on different forms of renal replacement therapy (RRT) of 374 children and adolescents with chronic renal failure observed between 1969 and 1988 and compared the findings for the four subsequent 5-year periods. The proportion of children below 5 years of age rose from 21% to 47%. With time the incidence of glomerulonephritis increased and that of pyelonephritis decreased. As RRT became more common, more very young children and more adolescents were admitted to the study. In the last 5 years continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis (HD) were performed to the same extent as the initial form of RRT. The time a subject had to wait for a first transplant decreased from 36 to 21 months. Between 1969 and 1988 overall survival on any form of RRT increased to 77% after 10 years of therapy. In the last observation period 2-year patient survival was 100% both on HD and CAPD. First cadaver graft survival after 4 years improved from 25% in 1969-1973 to 69% in 1984-1988.

Monoclonal antibodies to renal brush border membrane maltase: age-associated antigenic alterations.

Monoclonal antibodies to maltase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) from young adult and aged rats were prepared by the hybridoma technique. Four cell lines producing antibodies of the IgG1 subclass to maltase were established. Two, designated 1F12E1 and 8B1G6, produced monoclonal antibodies specific for the catalytically active form of the enzyme found predominantly in enzyme preparations from young animals. The other two clones designated 7G10H3 and 2E1C10 produced monoclonal antibodies that reacted exclusively with an enzymatically inactive form of maltase found mostly in enzyme preparations from aged rats. The increased prevalence of an inactive form of the enzyme in the old rat accounts for the decreased maltase-specific activity previously reported in the senescent rat. The active and inactive maltase species were separated by immunoaffinity chromatography by using the monoclonal antibodies as ligands. The separated forms of the enzyme were not distinguished by NaDodSO4/polyacrylamide gel electrophoresis, peptide mapping of the CNBr-cleaved proteins, and the NH2-terminal residues of these peptides. This study demonstrates the presence of an altered, antigenically distinct enzyme in senescent animals. Critical issues on the mechanism of the aging process may be addressed by application of these findings.

Alteration of kidney brush border membrane maltase in aging rats.

The specific activities of membrane-bound maltase (alpha-d-glucoside glucohydrolase, EC 3.2.1.20) in renal cortex homogenates and isolated brush border membranes of senescent rats decreased about 30% compared to the specific activities of the enzyme from young adult animals. The decline was gradual and concomitant with the aging process. When the enzymes from rats of 25 and 6 months of age were solubilized and purified to homogeneity the same decrement with age was found, 32.5 and 46.1 units/mg of protein, respectively. This finding suggests that the decrease in maltase activity with age results from an alteration in the enzyme per se, rather than from a change in the enzyme's membrane environment, which was reflected secondarily as a loss in activity. Recoveries of enzyme activity and protein and fold-purification were similar for young and old maltase, indicating that the age-related difference in specific activities of the pure enzymes was not due to the selective purification of an altered species of enzyme. The age-associated difference in activity was not attributable to the presence of proteolytic activity in the homogenate nor to the presence of an activator in the young or an inhibitor in the old kidney. The pure enzymes from young adult and aged animals did not differ in molecular weight, electrophoretic mobility, amino acid composition and Km value. Circular dichroism spectra revealed that both the young and old enzymes contained beta-structure. However, the old enzyme had more helical structure than did the young enzyme, suggesting a conformational alteration with age.

Prostaglandin F2alpha human blood during labor.

Plasma prostaglandin F2alpha (PGF2alpha) concentrations were determined by radioimmunoassay in serial samples during labor and the early postpartum period. PGF2alpha was also measured during and between contractions every 20 to 30 seconds. The highest levels of PGF2alpha were found during expulsion of the fetus and placenta with an additional rise half an hour after delivery and a decrease 2 hours after delivery to the levels of first stage of labor. PGF2alpha values from cord blood were higher than in maternal peripheral blood in labor. The maximum PGF2alpha concentration occurred between 100 to 120 seconds after the peak uterine contraction and between 40 and 60 seconds prior to peak of the next contraction. The possible explanation is that PGF2alpha initiates uterine contractions and plays a role in the maintenance of labor, in the expulsion of the fetus and the placenta, and in the involution after delivery.

The effect of indomethacin on plasma levels of prostaglandin F2alpha in women in labour.

Prostaglandin F2alpha was measured by means of radiommunoassay in the serum of women in the active phase of term labour before and after rectal indomethacin administration. Samples of blood were collected every 20 or 30 seconds, between and during contractions. There was a significant decrease of the level of PGF2alpha in plasma 30 to 30 minutes after indomethacin administration, but the pattern of rapid short-term fluctuations in prostaglandin levels was unaltered.