Genotypic and phenotypic spectrum of cytosolic phosphoenolpyruvate carboxykinase deficiency.

OBJECTIVES: Pathogenic biallelic variants in PCK1 coding for the cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) cause PEPCK-C deficiency, a rare disorder of gluconeogenesis presenting with hypoglycemia, lactic acidosis, and hepatopathy. To date, there has been no systematic analysis of its phenotypic, biochemical, and genetic spectrum. METHODS: All currently published individuals and a novel patient with genetically confirmed PEPCK-C deficiency were included. Clinical, biochemical, and genetic findings were analyzed. Protein and in-silico prediction score modeling was applied to analyze potential variant effects. RESULTS: Thirty-two individuals from 25 families were found, including one previously unreported patient. The typical biochemical pattern was hypoglycemia triggered by catabolic situations, elevated urinary concentrations of tricarboxylic acid cycle metabolites, mildly elevated alanine and aspartate aminotransferase and elevated lactate concentrations in serum. Plasma glutamine concentrations were elevated in some patients and may be a suitable marker for newborn screening. With adequate treatment, biochemical abnormalities usually normalized following a hypoglycemic episode. Symptom onset usually occurred in infancy with a broad range from neonatal age to adulthood. Regardless of the genotype, different phenotypes with a broad clinical spectrum were found. To date, eight genotypes with nine different PCK1 variants were identified, of which alleles with the recurrent variant c.925G > A; p.(Gly309Arg) are predominant and appear to be endemic in the Finnish population. Protein modeling suggests altered manganese- and substrate-binding as superordinate pathomechanisms. CONCLUSIONS: Environmental factors appear to be the main determinant for the phenotype in patients with biallelic variants in PCK1. Based on the biochemical pattern, PEPCK-C deficiency is a recognizable cause of childhood hypoglycemia. It is a treatable disease and early diagnosis is important to prevent metabolic derailment and morbidity. Newborn screening can identify at least a sub-cohort of affected individuals through elevated glutamine concentrations in dry blood.

Cardiac phenotype in propionic acidemia - Results of an observational monocentric study.

BACKGROUND: Propionic acidemia (PA) is an organic aciduria caused by inherited deficiency of propionyl-CoA carboxylase. Left ventricular dysfunction and QT prolongation may lead to life-threatening complications. Systematic analyses of cardiac phenotypes, in particular effects of specific cardiac therapies, are scarce. METHODS: In this longitudinal observational monocentric study (data from 1989 to 2017) all PA patients treated at our center were included. Echocardiographic parameters (left ventricular end-diastolic diameter: LVEDD, left ventricular shortening fraction, mitral valve Doppler inflow pattern) and 12­lead electrocardiogram recordings (corrected QT interval: QTc) were analyzed. Symptomatic patients were dichotomized to the group "early-onset" (symptoms within 28 days of life) and "late-onset" (symptoms after 28 days). Associations between cardiac function, LVEDD, QTc and clinical parameters (age at onset, beta-blocker or Angiotensin-converting enzyme inhibitor = ACE-I therapy) were analyzed. RESULTS: 18 patients with PA were enrolled, 17 of them were symptomatic and one asymptomatic, with a median age at diagnosis of 6 days. 14/17 (82%) had early onset disease manifestation. Systolic left ventricular dysfunction (i.e. hypokinetic phenotype of cardiomyopathy) was diagnosed in 7/18 (39%) patients at a median age of 14.4 years, all had early onset. Two patients had a dilated left ventricle and systolic left ventricular dysfunction (i.e. dilated hypokinetic phenotype - dilated cardiomyopathy). Diastolic left ventricular dysfunction was found in 11/18 (61%) individuals, typically preceding systolic left ventricular dysfunction. ACE-I therapy did not improve systolic left ventricular function. Mean QTc was 445 ms (+/- 18.11 ms). Longer QTc was associated with larger LVEDD. CONCLUSIONS: Systolic left ventricular dysfunction was found in 39% of patients, reflecting high disease severity. Two thirds of all individuals showed signs of diastolic left ventricular dysfunction usually preceding systolic left ventricular dysfunction; it therefore may be considered as an indicator for early cardiac disease manifestation, possibly allowing earlier treatment modification. Unresponsiveness to routine cardiac therapy highlights the need to evaluate further strategies, such as liver transplantation.

Molecular and biochemical alterations in tubular epithelial cells of patients with isolated methylmalonic aciduria.

Methylmalonic acidurias (MMAurias) are a group of inherited disorders in the catabolism of branched-chain amino acids, odd-chain fatty acids and cholesterol caused by complete or partial deficiency of methylmalonyl-CoA mutase (mut(0) and mut(-) subtype respectively) and by defects in the metabolism of its cofactor 5'-deoxyadenosylcobalamin (cblA, cblB or cblD variant 2 type). A long-term complication found in patients with mut(0) and cblB variant is chronic tubulointerstitial nephritis. The underlying pathomechanism has remained unknown. We established an in vitro model of tubular epithelial cells from patient urine (hTEC; 9 controls, 5 mut(0), 1 cblB). In all human tubular epithelial cell (hTEC) lines we found specific tubular markers (AQP1, UMOD, AQP2). Patient cells showed disturbance of energy metabolism in glycolysis, mitochondrial respiratory chain and Krebs cycle in concert with increased reactive oxygen species (ROS) formation. Electron micrographs indicated increased autophagosome production and endoplasmic reticulum stress, which was supported by positive acridine orange staining and elevated levels of LC3 II, P62 and pIRE1. Screening mTOR signaling revealed a release of inhibition of autophagy. Patient hTEC produced and secreted elevated amounts of the pro-inflammatory cytokine IL8, which was highly correlated with the acridine orange staining. Summarizing, hTEC of MMAuria patients are characterized by disturbed energy metabolism and ROS production that lead to increased autophagy and IL8 secretion.

MRI and (1)H-MRS in adenosine kinase deficiency.

INTRODUCTION: Adenosine kinase deficiency (ADK deficiency) is a recently described disorder of methionine and adenosine metabolism resulting in a neurological phenotype with developmental delay, muscular hypotonia, and epilepsy as well as variable systemic manifestations. The underlying neuropathology is poorly understood. We have investigated MRI and (1)H-MRS changes in ADK deficiency in order to better understand the in vivo neuropathologic changes of ADK deficiency. METHODS: Systematic evaluation of 21 MRIs from eight patients (age range 9 days-14.6 years, mean 3.9 years, median 2.7 years) including diffusion-weighted imaging in six and (1)H-MRS in five patients. RESULTS: Brain maturation was delayed in the neonatal period and in infancy (6/6), but ultimately complete. White matter changes occurring in five of eight patients were discrete, periventricular, and unspecific (4/5), or diffuse with sparing of optic radiation, corona radiata, and pyramidal tracts (1/5). Choline was low in white matter spectra (3/3), while there was no indication of low creatine in white matter or basal ganglia (5/5), and diffusion was variably decreased or increased. Central tegmental tract hyperintensity was a common finding (6/8), as was supratentorial atrophy (6/8). CONCLUSIONS: MRI changes in ADK deficiency consist of delayed but ultimately completed brain maturation with later onset of mostly unspecific white matter changes and potentially transient central tegmental tract hyperintensity. Immaturity on neonatal MRI is consistent with prenatal onset of disease and reduced choline with lower membrane turnover resulting in delayed myelination and deficient myelin maintenance.

Renal involvement in a patient with cobalamin A type (cblA) methylmalonic aciduria: a 42-year follow-up.

Chronic renal failure is a well-known long-term complication of methylmalonic aciduria (MMA-uria), occurring even under apparently optimal metabolic management. The onset of renal dysfunction seems to be dependent on the type of defect and vitamin B12-responsiveness. We report on a patient with a vitamin B12-responsive cobalamin A type (cblA) MMA-uria caused by a homozygous stop mutation (p.R145X) in the cobalamin A gene (MMAA). She was diagnosed with chronic kidney disease (CKD) stage III at the age of 12 years. Following re-evaluation, the patient received vitamin B12 (hydroxocobalamin) treatment, resulting in a significant decrease in the concentration of methylmalonic acid (MMA) in urine and plasma. Until age 29 years glomerular filtration rate remained stable probably due to hydroxocobalamin treatment slowing down progression to end-stage renal failure. Kidney biopsies showed non-specific manifestations of chronic interstitial inflammation. The patient received a renal transplant at age 35 years. Under continuous treatment with hydroxocobalamin there is no evidence of kidney damage due to MMA-uria until the last follow-up 6 years after transplantation. This case report illustrates (i) a long-term follow-up of a patient with MMA-uria due to cblA deficiency, (ii) the involvement of the kidney as a target organ and (iii) the importance of early and adequate vitamin B12 substitution in responsive patients. Further investigation will be necessary to prove the protective effect of hydroxocobalamin in the kidney in vitamin B12-responsive patients.

Acid-sensing ion channel 3 expressed in type B synoviocytes and chondrocytes modulates hyaluronan expression and release.

BACKGROUND: Rheumatoid arthritis is an inflammatory disease marked by intra-articular decreases in pH, aberrant hyaluronan regulation and destruction of bone and cartilage. Acid-sensing ion channels (ASICs) are the primary acid sensors in the nervous system, particularly in sensory neurons and are important in nociception. ASIC3 was recently discovered in synoviocytes, non-neuronal joint cells critical to the inflammatory process. OBJECTIVES: To investigate the role of ASIC3 in joint tissue, specifically the relationship between ASIC3 and hyaluronan and the response to decreased pH. METHODS: Histochemical methods were used to compare morphology, hyaluronan expression and ASIC3 expression in ASIC3+/+ and ASIC3-/- mouse knee joints. Isolated fibroblast-like synoviocytes (FLS) were used to examine hyaluronan release and intracellular calcium in response to decreases in pH. RESULTS: In tissue sections from ASIC3+/+ mice, ASIC3 localised to articular cartilage, growth plate, meniscus and type B synoviocytes. In cultured FLS, ASIC3 mRNA and protein was also expressed. In FLS cultures, pH 5.5 increased hyaluronan release in ASIC3+/+ FLS, but not ASIC3-/- FLS. In FLS from ASIC3+/+ mice, approximately 50% of cells (25/53) increased intracellular calcium while only 24% (14/59) showed an increase in ASIC3-/- FLS. Of the cells that responded to pH 5.5, there was significantly less intracellular calcium increases in ASIC3-/- FLS compared to ASIC3+/+ FLS. CONCLUSION: ASIC3 may serve as a pH sensor in synoviocytes and be important for modulation of expression of hyaluronan within joint tissue.

Long-term exposure of human proximal tubule cells to hydroxycobalamin[c-lactam] as a possible model to study renal disease in methylmalonic acidurias.

Dysfunction of proximal tubules resulting in tubulointerstitial nephritis and chronic renal failure is a frequent long-term complication of methylmalonic acidurias. However, the underlying pathomechanisms have not yet been extensively studied owing to the lack of suitable in vitro and in vivo models. Application of hydroxycobalamin[c-lactam] has been shown to inhibit the metabolism of hydroxycobalamin and, thereby, to induce methylmalonic aciduria in rats, oligodendrocytes, and rat hepatocytes. Our study characterizes the biochemical and bioenergetic effects of long-term exposure of human proximal tubule cells to hydroxycobalamin[c-lactam], aiming to establish a novel in vitro model for the renal pathogenesis of methylmalonic acidurias. Incubation of human proximal tubule cells with hydroxycobalamin[c-lactam] and propionic acid resulted in a strong, time-dependent intra- and extracellular accumulation of methylmalonic acid. Bioenergetic studies of respiratory chain enzyme complexes revealed an increase of complex II-IV activity after 2 weeks and an increase of complex I and IV activity as well as a decrease of complex II and III activity after 3 weeks of incubation. In addition, human proximal tubule cells displayed reduced glutathione content after the exposure to hydroxycobalamin[c-lactam] and propionic acid.

Prediction of outcome in isolated methylmalonic acidurias: combined use of clinical and biochemical parameters.

Objectives Isolated methylmalonic acidurias (MMAurias) are caused by deficiency of methylmalonyl-CoA mutase or by defects in the synthesis of its cofactor 5'-deoxyadenosylcobalamin. The aim of this study was to evaluate which parameters best predicted the long-term outcome. Methods Standardized questionnaires were sent to 20 European metabolic centres asking for age at diagnosis, birth decade, diagnostic work-up, cobalamin responsiveness, enzymatic subgroup (mut(0), mut(-), cblA, cblB) and different aspects of long-term outcome. Results 273 patients were included. Neonatal onset of the disease was associated with increased mortality rate, high frequency of developmental delay, and severe handicap. Cobalamin non-responsive patients with neonatal onset born in the 1970s and 1980s had a particularly poor outcome. A more favourable outcome was found in patients with late onset of symptoms, especially when cobalamin responsive or classified as mut(-). Prevention of neonatal crises in pre-symptomatically diagnosed newborns was identified as a protective factor concerning handicap. Chronic renal failure manifested earlier in mut(0) patients than in other enzymatic subgroups. Conclusion Outcome in MMAurias is best predicted by the enzymatic subgroup, cobalamin responsiveness, age at onset and birth decade. The prognosis is still unfavourable in patients with neonatal metabolic crises and non-responsiveness to cobalamin, in particular mut(0) patients.

Newborn screening for methylmalonic acidurias--optimization by statistical parameter combination.

With the introduction of tandem mass spectrometry, newborn screening for disorders of propionate metabolism became widely available. However, there is controversy whether population screening for these disorders should be performed. The most widely used primary metabolite C(3) itself has a poor specificity or lacks 100% sensitivity for milder forms and/or defects of cobalamin metabolism. Strategies to improve specificity have included the calculation of metabolite ratios (e.g. C(3)/C(2)) or second-tier strategies with analysis of methylmalonic acid or 2-methylcitric acid from the primary screening specimen. We report the results of a new statistical approach to identify parameter combinations that allow for 100% sensitivity as well as increased specificity. The promising results of this alternative approach will have to be substantiated on larger data sets.

Looking beyond the basal ganglia: the spectrum of MRI changes in methylmalonic acidaemia.

We report imaging abnormalities from 5 brain MR examinations in 4 children with methylmalonic acidaemia between the ages of 20 days and 31 months. In addition to bilateral basal ganglia lesions (pallidum) observed in 3 of 4 children, we found signs of delayed brain maturation (myelination delay, immature gyral pattern, incomplete opercularization) in all children and signs of a white matter disorder in the 3 older children. Unexpectedly, brainstem and cerebellar changes were present in all children. Reviewing the brain imaging changes reported for methylmalonic acidaemia, we discuss the findings and patterns observed in our patients. We postulate that delayed myelination and signs of a white matter disorder as well as brainstem and cerebellar involvement are common findings and may be due to a chronic neurotoxic effect on the developing and ageing brain.

Neurodegeneration and chronic renal failure in methylmalonic aciduria--a pathophysiological approach.

In the last decades the survival of patients with methylmalonic aciduria has been improved. However, the overall outcome of affected patients remains disappointing. The disease course is often complicated by acute life-threatening metabolic crises, which can result in multiple organ failure or even death, resembling primary defects of mitochondrial energy metabolism. Biochemical abnormalities during metabolic derangement, such as metabolic acidosis, ketonaemia/ketonuria, lactic acidosis, hypoglycaemia and hyperammonaemia, suggest mitochondrial dysfunction. In addition, long-term complications such as chronic renal failure and neurological disease are frequently found. Neuropathophysiological studies have focused on various effects caused by accumulation of putatively toxic organic acids, the so-called 'toxic metabolite' hypothesis. In previous studies, methylmalonate (MMA) has been considered as the major neurotoxin in methylmalonic aciduria, whereas more recent studies have highlighted a synergistic inhibition of mitochondrial energy metabolism (pyruvate dehydrogenase complex, tricarboxylic acid cycle, respiratory chain, mitochondrial salvage pathway of deoxyribonucleoside triphosphate (dNTP)) induced by propionyl-CoA, 2-methylcitrate and MMA as the key pathomechanism of inherited disorders of propionate metabolism. Intracerebral accumulation of toxic metabolites ('trapping' hypothesis') is considered a biochemical risk factor for neurodegeneration. Secondary effects of mitochondrial dysfunction, such as oxidative stress and impaired mtDNA homeostasis, contribute to pathogenesis of these disorders. The underlying pathomechanisms of chronic renal insufficiency in methylmalonic acidurias are not yet understood. We hypothesize that renal and cerebral pathomechanisms share some similarities, such as an involvement of dicarboxylic acid transport. This review aims to give a comprehensive overview on recent pathomechanistic concepts for methylmalonic acidurias.

Pathogenesis of CNS involvement in disorders of amino and organic acid metabolism.

Inherited disorders of amino and organic acid metabolism have a high cumulative frequency, and despite heterogeneous aetiology and varying clinical presentation, the manifestation of neurological disease is common. It has been demonstrated for some of these diseases that accumulating pathological metabolites are directly involved in the manifestation of neurological disease. Various pathomechanisms have been suggested in different in vitro and in vivo models including an impairment of brain energy metabolism, an imbalance of excitatory and inhibitory neurotransmission, altered transport across the blood-brain barrier and between glial cells and neurons, impairment of myelination and disturbed neuronal efflux of metabolic water. This review summarizes recent knowledge on pathomechanisms involved in phenylketonuria, glutaric aciduria type I, succinic semialdehyde dehydrogenase deficiency and aspartoacylase deficiency with examples, highlighting general as well as disease-specific concepts and their putative impact on treatment.

Diagnostic work-up and management of patients with isolated methylmalonic acidurias in European metabolic centres.

The long-term outcome of patients with methylmalonic aciduria (MMA) is still uncertain due to a high frequency of complications such as chronic renal failure and metabolic stroke. The understanding of this disease is hampered by a huge variation in the management of these patients. The major aim of this study was to evaluate the current practice in different European metabolic centres. A standardized questionnaire was sent to 20 metabolic centres asking for standard procedures for confirmation of diagnosis, testing cobalamin responsiveness, dietary treatment, pharmacotherapy, and biochemical and clinical monitoring. Sixteen of 20 metabolic centres (80%) returned questionnaires on 183 patients: 89 of the patients were classified as mut(0), 36 as mut(-), 13 as cblA, 7 as cblB, and 38 as cblA/B. (1) Confirmation of diagnosis: All centres investigate enzyme activity by propionate fixation in fibroblasts; six centres also perform mutation analysis. (2) Cobalamin response: Ten centres follow standardized protocols showing large variations. A reliable exclusion of nonspecific effects has not yet been achieved by these protocols. (3) Long-term treatment: In cobalamin-responsive patients, most centres use hydroxocobalamin (1-14 mg/week i.m. or 5-20 mg/week orally), while two centres use cyanocobalamin. All cobalamin-nonresponsive patients and most cobalamin-responsive patients are supplemented with L: -carnitine (50-100 mg/kg per day). Fourteen centres use intestinal decontamination by antibiotic therapy. Most centres follow D-A-CH (n = 6) or Dewey (n = 4) recommendations for protein requirements. Fourteen centres regularly use precursor-free amino acid supplements. Standardized monitoring protocols are available in seven centres, again showing high variability.

Enzymatic and metabolic evidence for a region specific mitochondrial dysfunction in brains of murine succinic semialdehyde dehydrogenase deficiency (Aldh5a1-/- mice).

Succinic semialdehyde dehydrogenase deficiency, a rare inherited defect of gamma-aminobutyrate (GABA) catabolism, presents with characteristic biochemical abnormalities in the central nervous system (CNS). These include elevated concentrations of GABA, gamma-hydroxybutyrate (GHB), succinic semialdehyde (SSA), 4,5-dihydroxyhexanoic acid (DHHA) and alanine as well as decreased concentrations of glutamine. GABA degradation is coupled to Krebs cycle function in mammalian CNS ("GABA shunt") through succinate and alpha-ketoglutarate. Accordingly, we hypothesized that disruption of Krebs cycle and respiratory chain function in the CNS is involved in the neuropathogenesis of this disease. For this purpose, we investigated cerebral activities of Krebs cycle and respiratory chain enzymes as well as the glutathione content in Aldh5a1(-/-) mice, a recently generated mouse model for this disease. In CNS tissue of Aldh5a1(-/-) mice, we found a significantly decreased glutathione content (hippocampus, cortex) and decreased activities of complexes I-IV (hippocampus) suggesting increased oxidative stress and mitochondrial dysfunction. However, specific activities of Krebs cycle and respiratory chain were not affected by GABA, GHB, SSA, or DHHA (up to 1 mmol/L). Although our results suggest hippocampal and cortical dysfunction in Aldh5a1(-/-) brain, we found no evidence that accumulating key metabolites of SSADH deficiency directly induce impairment of energy metabolism.

Guideline for the diagnosis and management of glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I).

Glutaryl-CoA dehydrogenase (GCDH) deficiency is an autosomal recessive disease with an estimated overall prevalence of 1 in 100 000 newborns. Biochemically, the disease is characterized by accumulation of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine, which can be detected by gas chromatography-mass spectrometry of organic acids or tandem mass spectrometry of acylcarnitines. Clinically, the disease course is usually determined by acute encephalopathic crises precipitated by infectious diseases, immunizations, and surgery during infancy or childhood. The characteristic neurological sequel is acute striatal injury and, subsequently, dystonia. During the last three decades attempts have been made to establish and optimize therapy for GCDH deficiency. Maintenance treatment consisting of a diet combined with oral supplementation of L: -carnitine, and an intensified emergency treatment during acute episodes of intercurrent illness have been applied to the majority of patients. This treatment strategy has significantly reduced the frequency of acute encephalopathic crises in early-diagnosed patients. Therefore, GCDH deficiency is now considered to be a treatable condition. However, significant differences exist in the diagnostic procedure and management of affected patients so that there is a wide variation of the outcome, in particular of pre-symptomatically diagnosed patients. At this time of rapid expansion of neonatal screening for GCDH deficiency, the major aim of this guideline is to re-assess the common practice and to formulate recommendations for diagnosis and management of GCDH deficiency based on the best available evidence.

Neonatal screening for glutaric aciduria type I: strategies to proceed.

Acute encephalopathic crisis in glutaric aciduria type I results in an unfavourable disease course and poor outcome, dominated by dystonia, feeding problems, seizures and reduced life expectancy. A conditio sine qua non for the prevention of irreversible brain damage is timely diagnosis and start of therapy, i.e. before the onset of neurological disease. As there are no specific clinical signs or symptoms that allow a reliable detection of these patients before the manifestation of encephalopathic crises, neonatal screening programmes for glutaric aciduria type I have been established in some countries using analysis of glutarylcarnitine in dried blood spots by tandem mass spectrometry. This article summarizes recent strategies, pitfalls and shortcomings of mass screening for glutaric aciduria type I, focusing on the relevant risk of missing patients with a mild biochemical phenotype (i.e. low excretors). Furthermore, it evaluates a binary strategy--using glutarylcarnitine as primary variable and glutarylcarnitine/acylcarnitine ratios as secondary variable--to improve the diagnostic sensitivity and specificity of neonatal screening for glutaric aciduria type I. An optimization of diagnostic as well as therapeutic procedures must be achieved before screening for glutaric aciduria type I can be regarded as reliable and beneficial for all patients.

The aetiology of neurological complications of organic acidaemias--a role for the blood-brain barrier.

The blood-brain barrier (BBB) metabolically isolates the central nervous system (CNS) from the circulation and protects it against fluctuations of hydrophilic nutrients in plasma and from intoxication. Recent studies have shown that dicarboxylic acids (DCAs) are transported across the blood-brain barrier at very low rates. In organic acidaemias, neurological complications are common. We hypothesize that, as a result of the very limited efflux, in certain organic acidaemias there is pathological accumulation of DCAs (e.g. glutarate, 3-hydroxyglutarate, D-2- and L-2-hydroxyglutarate, methylmalonate) in the brain secondary to the metabolic block. At high concentrations some of these compounds may become neurotoxic. Treatment should be aimed at preventing the accumulation of these compounds using our understanding of the properties of the BBB.

Hybrid resection of a giant thigh plexiform neurofibroma.

PRESENTATION OF CASE: Authors present a case of a 55 year old patient with Type 1 neurofibromatosis (NF1) and a very large right thigh plexiform neurofibroma. The patient had increasing difficulty with mobilization due to this enlarging bulky mass. Preoperative embolization reduced the bleeding risk at surgery allowing successful gross resection of the mass by a multidisciplinary surgical team. Limb function was restored to normal. DISCUSSION: Massive plexiform neurofibromatosis is a rare expression of von Recklinghausen's disease or NF1. These large masses result in severe disfigurement and significant functional disability. They are extremely vascular and there is potential for malignant transformation. CONCLUSION: These massive tumors require complex preoperative, intraoperative and postoperative management strategies with involvement from a multidisplinary team. We discuss the challenges of surgical intervention and to discuss the current literature.

Disseminated intravascular meconium in a newborn with meconium peritonitis.

A 3-day-old premature infant with meconium peritonitis, periventricular leukomalacia, and pulmonary hypertension died with respiratory insufficiency. An autopsy disclosed intravascular squamous cells in the lungs, brain, liver, pancreas, and kidneys. Numerous pulmonary capillaries and arterioles were occluded by squamous cells, accounting for pulmonary hypertension. Brain parenchyma surrounding occluded cerebral vessels showed infarct and gliosis. A mediastinal lymph node filled with squamous cells alluded to the mechanism by which these cells from the peritoneal cavity likely entered the bloodstream--namely, via diaphragmatic pores connecting with lymphatics. Thus, disseminated intravascular meconium rarely may complicate meconium peritonitis and have devastating consequences.

Decreased catecholamine-induced cell death in B lymphocytes from patients with rheumatoid arthritis.

The expression of beta2-adrenergic receptors (beta2-R) on B lymphocytes and agonist-induced cAMP production is reduced in patients with rheumatoid arthritis (RA). To further study functional consequences of the diminished beta2-R density on B lymphocytes in RA patients, agonist-induced cell death was evaluated and compared to healthy controls. B lymphocytes from patients with RA and healthy controls were activated with anti-IgM-antibody. Coincubation was carried out with isoprenaline (iso, 0.001-10 microM). Apoptotic and necrotic cells were determined using Annexin-V and propidium-iodide staining. beta2-R-induced cell death in B cells from healthy volunteers was stimulated after 24 h (medium, 21.2 +/- 1.6%; iso, 34.6 +/- 4.4%; increase 59.3 +/- 10.1%). However, in RA patients the increase in cell death following beta2-R stimulation (21.8 +/- 8.9%) was significantly impaired (p = 0.02). Our data demonstrate that catecholamine-induced cell death after stimulation of beta2-R on B lymphocytes is decreased in RA patients, possibly contributing to the pathogenesis of the disease.