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The effects of fasting for 7 days were investigated in 13 patients with rheumatoid arthritis (RA) in comparison with a control regimen in a cross-over trial. The effects of fasting on clinical performance and blood neutrophil functions were studied. During fasting, with a mean weight loss of 5.1 kg, clinical inflammation in the joints and the erythrocyte sedimentation rate (ESR) decreased. During the control period the joints either remained unchanged or deteriorated, and no change was observed in the body weight or the ESR. The locomotion of neutrophils under agarose, induced by a reference serum, decreased during the fasting period (p less than 0.001), but no change in their locomotion was induced by an Escherichia coli bacterial factor. During the control period, however, the locomotion induced by either stimulant was significantly decreased. Generation of migration-stimulating factors from the patients' plasma declined 3 days after the end of fasting (p less than 0.001). The adherence of the neutrophils to nylon fibres was unchanged during both periods. The bactericidal capacity improved during fasting, both in comparison with the initial value (p less than 0.005) and with the values from the control period (p less than 0.001). An association was found between improvement in inflammatory activity of the joints and enhancement of neutrophil bactericidal capacity. Fasting appears to improve the clinical status of patients with RA. This could partly be due to the observed changes in the functions of the neutrophils, since the latter contribute to the inflammatory joint reactions. [ABSTRACT FROM PUBLISHER]

It has been demonstrated, that long-term chronic tryptophan deficiency, results in decreased serotonin synthesis, which may lead to low bone mass and low bone formation. Findings from studies in male patients with idiopathic osteoporosis suggested a decreased transport of tryptophan in erythrocytes of osteoporotic patients, indicating that serotonin system defects may be involved in the etiology of low bone mass. Tryptophan is the precursor of serotonin, and a disturbed transport of tryptophan is implicated in altered serotonin synthesis. However, no study has investigated the tryptophan transport kinetics in MIO patients. The aim of this study is to investigate the kinetic parameters of tryptophan transport in fibroblasts derived from MIO patients compared to age and sex matched controls. Fibroblast cells were cultured from skin biopsies obtained from 14 patients diagnosed with Male Idiopathic Osteoporosis and from 13 healthy age-sex matched controls, without a diagnosis of osteoporosis. Transport of the amino acid tryptophan across the cell membrane was measured by the cluster tray method. The kinetic parameters, maximal transport capacity (V max ) and affinity constant (K m ) were determined by using the Lineweaver-Burke plot equation. The results of this study have shown a significantly lower mean value for V max ( p  = 0.0138) and lower K m mean value ( p  = 0.0009) of tryptophan transport in fibroblasts of MIO patients compared to the control group. A lower V max implied a decreased tryptophan transport availability in MIO patients. In conclusion, reduced cellular tryptophan availability in MIO patients might result in reduced brain serotonin synthesis and its endogenous levels in peripheral tissues, and this may contribute to low bone mass/formation. The findings of the present study could contribute to the etiology of idiopathic osteoporosis and for the development of novel approaches for diagnosis, treatment and management strategies of MIO.

The molecular pathogenesis of bipolar disorder (BPD) is poorly understood. Using human-induced pluripotent stem cells (hiPSCs) to unravel such mechanisms in polygenic diseases is generally challenging. However, hiPSCs from BPD patients responsive to lithium offered unique opportunities to discern lithium's target and hence gain molecular insight into BPD. By profiling the proteomics of BDP-hiPSC-derived neurons, we found that lithium alters the phosphorylation state of collapsin response mediator protein-2 (CRMP2). Active nonphosphorylated CRMP2, which binds cytoskeleton, is present throughout the neuron; inactive phosphorylated CRMP2, which dissociates from cytoskeleton, exits dendritic spines. CRMP2 elimination yields aberrant dendritogenesis with diminished spine density and lost lithium responsiveness (LiR). The "set-point" for the ratio of pCRMP2:CRMP2 is elevated uniquely in hiPSC-derived neurons from LiR BPD patients, but not with other psychiatric (including lithium-nonresponsive BPD) and neurological disorders. Lithium (and other pathway modulators) lowers pCRMP2, increasing spine area and density. Human BPD brains show similarly elevated ratios and diminished spine densities; lithium therapy normalizes the ratios and spines. Consistent with such "spine-opathies," human LiR BPD neurons with abnormal ratios evince abnormally steep slopes for calcium flux; lithium normalizes both. Behaviorally, transgenic mice that reproduce lithium's postulated site-of-action in dephosphorylating CRMP2 emulate LiR in BPD. These data suggest that the "lithium response pathway" in BPD governs CRMP2's phosphorylation, which regulates cytoskeletal organization, particularly in spines, modulating neural networks. Aberrations in the posttranslational regulation of this developmentally critical molecule may underlie LiR BPD pathogenesis. Instructively, examining the proteomic profile in hiPSCs of a functional agent-even one whose mechanism-of-action is unknown-might reveal otherwise inscrutable intracellular pathogenic pathways., Competing Interests: Conflict of interest statement: R.C.B.B., L.M.B., G.C., J.S.N., H.M., and J.H.P. are employees of private companies. Their role in the study was solely as researchers with no financial or proprietary involvement.

Schizophrenia affecting almost 1% and bipolar disorder affecting almost 3%-5% of the global population constitute two severe mental disorders. The catecholaminergic and the serotonergic pathways have been proved to play an important role in the development of schizophrenia, bipolar disorder, and other related psychiatric disorders. The aim of the study was to perform and interpret the results of a comparative genomic profiling study in schizophrenic patients as well as in healthy controls and in patients with bipolar disorder and try to relate and integrate our results with an aberrant amino acid transport through cell membranes. In particular we have focused on genes and mechanisms involved in amino acid transport through cell membranes from whole genome expression profiling data. We performed bioinformatic analysis on raw data derived from four different published studies. In two studies postmortem samples from prefrontal cortices, derived from patients with bipolar disorder, schizophrenia, and control subjects, have been used. In another study we used samples from postmortem orbitofrontal cortex of bipolar subjects while the final study was performed based on raw data from a gene expression profiling dataset in the postmortem superior temporal cortex of schizophrenics. The data were downloaded from NCBI's GEO datasets.

Background: The catecholaminergic and serotonergic neurotransmitter systems are implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). The amino acid tyrosine is the precursor for synthesis of the catecholamines dopamine and norepinephrine, while tryptophan is the precursor of serotonin. A disturbed transport of tyrosine, as well as other amino acids, has been found in a number of other psychiatric disorders, such as schizophrenia, bipolar disorder and autism, when using the fibroblast cell model. Hence, the aim of this study was to explore whether children with ADHD may have disturbed amino acid transport., Methods: Fibroblast cells were cultured from skin biopsies obtained from 14 boys diagnosed with ADHD and from 13 matching boys without a diagnosis of a developmental disorder. Transport of the amino acids tyrosine, tryptophan and alanine across the cell membrane was measured by the cluster tray method. The kinetic parameters, maximal transport capacity (V(max)) and affinity constant (K(m)) were determined. Any difference between the two groups was analyzed by Student's unpaired t-test or the Mann Whitney U test., Results: The ADHD group had significantly decreased V(max) (p = 0.039) and K(m) (increased affinity) (p = 0.010) of tryptophan transport in comparison to controls. They also had a significantly higher V(max)of alanine transport (p = 0.031), but the Km of alanine transport did not differ significantly. There were no significant differences in any of the kinetic parameters regarding tyrosine transport in fibroblasts for the ADHD group., Conclusions: Tryptophan uses the same transport systems in both fibroblasts and at the blood brain barrier (BBB). Hence, a decreased transport capacity of tryptophan implies that less tryptophan is being transported across the BBB in the ADHD group. This could lead to deficient serotonin access in the brain that might cause disturbances in both the serotonergic and the catecholaminergic neurotransmitter systems, since these systems are highly interconnected. The physiological importance of an elevated transport capacity of alanine to the brain is not known to date.

There are indications that serotonergic neurotransmission is disturbed in several psychiatric disorders. One explanation may be disturbed transport of tryptophan (precursor for serotonin synthesis) across cell membranes. Human fibroblast cells offer an advantageous model to study the transport of amino acids across cell membranes, since they are easy to propagate and the environmental factors can be controlled. The aim of this study was to functionally characterize tryptophan transport and to identify the main transporters of tryptophan in fibroblast cell lines from healthy controls.Tryptophan kinetic parameters (V(max) and K(m)) at low and high concentrations were measured in fibroblasts using the cluster tray method. Uptake of (3)H (5)-L-tryptophan at different concentrations in the presence and absence of excess concentrations of inhibitors or combinations of inhibitors of amino acid transporters were also measured. Tryptophan transport at high concentration (0.5 mM) had low affinity and high V(max) and the LAT1 isoform of system-L was responsible for approximately 40% of the total uptake of tryptophan. In comparison, tryptophan transport at low concentration (50 nM) had higher affinity, lower V(max) and approximately 80% of tryptophan uptake was transported by system-L with LAT1 as the major isoform. The uptake of tryptophan at the low concentration was mainly sodium (Na(+)) dependent, while uptake at high substrate concentration was mainly Na(+) independent. A series of different transporter inhibitors had varying inhibitory effects on tryptophan uptake.This study indicates that tryptophan is transported by multiple transporters that are active at different substrate concentrations in human fibroblast cells. The tryptophan transport trough system-L was mainly facilitated by the LAT1 isoform, at both low and high substrate concentrations of tryptophan.

Several mechanisms have been suggested to account for altered dopaminergic neurotransmission in schizophrenia. The brain is the only organ for which amino-acid transport is limited and competition for transport over the blood-brain barrier (BBB) occurs at physiological plasma concentrations. One line of research suggests that patients with schizophrenia have altered brain levels of the essential amino acid tyrosine, the precursor for the synthesis of dopamine. The most common hypothesis is that less tyrosine is available because of competition with elevated levels of other amino acids. By consequence, the synthesis of dopamine in the brain will decrease. In contrast, another line of evidence suggests a change in the affinity for one of the transport proteins. A limitation of this research has been that the systems for amino-acid transport across the BBB have not been fully characterized at a molecular or functional level. The L system is the major system for transport of tyrosine across cell membranes including the BBB. The A system is also involved in this transport. Earlier in-vitro studies using fibroblasts have demonstrated a normal L system in schizophrenia but nevertheless reduced tyrosine transport. The combination of molecular research, fibroblast techniques, and brain imaging provides a new basis for clinical research on the role of amino-acid membrane transport in schizophrenia.

Fibroblasts were cultured to determine the involvement of peroxisomes in cholesterol and dolichol synthesis. For this purpose, the behavior of cells from patients with Zellweger syndrome, with X-linked adrenoleukodystrophy, and from nondiseased control subjects was studied. Cells both after pretreatment with mevinolin and without pretreatment were incubated in a medium containing [3H]-mevalonate. In fibroblasts from patients with peroxisomal defects, the cholesterol content and mevalonate incorporation into cholesterol were decreased by 10-20% in comparison with control cells. Mevinolin pretreatment decreased the incorporation rate of [3H]-mevalonate into cholesterol but increased the labeling of ubiquinone and dolichol both in diseased and control cells. Squalene synthase activity was unchanged, whereas the activity of farnesyl-pyrophosphate synthase was increased in the diseased states. The results show that in patients with peroxisomal deficiency neither the amount nor the rate of synthesis of cholesterol and dolichol is reduced to any greater extent.

Cell lines transfected with the Swedish Alzheimer's disease amyloid precursor protein APP670/671 mutation release significantly more beta-amyloid than wild-type cells. Citron et al. [Proc. Natl. Acad. Sci. USA (1994) in press] have recently shown that fibroblasts carrying the APP670/671 mutation also release more beta-amyloid than control cells [1]. The present study confirms a ca. threefold increase in beta-amyloid release from mutation-bearing fibroblasts. APP mRNA levels did not differ between mutation-bearing and control cells, although mutation-bearing fibroblasts contained significantly more APP751/770 than controls. Mild stress decreased beta-amyloid secretion and increased APP751/770 levels in all cell lines. In conclusion, the proportion of APP committed to amyloidogenic processing is increased in fibroblasts from family members with the APP670/671 mutation, and this mutation may also compromise the APP stress response.

The activities of 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase were measured in fibroblasts from eight patients with 3-hydroxydicarboxylic aciduria. Measurement of 3-hydroxyacyl-CoA dehydrogenase with 3-ketopalmitoyl-CoA as substrate provided conclusive evidence for a deficiency of the long-chain 3-hydroxyacyl-CoA dehydrogenase in seven of the patients. Measurement of the enzyme in the normal direction cannot be recommended because this gives a higher residual activity. A trifunctional enzyme protein is responsible for the 3-hydroxyacyl-CoA dehydrogenase as well as for the hydratase and thiolase activities. A slight decrease in one or both of the other two activities was observed in four of the seven deficient patients, indicating that a defect in the trifunctional enzyme protein may affect the three enzyme activities to different degrees.

An alteration of dopaminergic transmission in the brain has been proposed for schizophrenia. To explore this, the rate constant for the intransport of L-tyrosine across the blood-brain barrier in healthy controls and in patients with schizophrenia (DSM-III-R) was determined with PET and L-[1-11C] tyrosine as the tracer. Kinetics for tyrosine transport were determined according to a two-compartment model using radioactivity data of arterial blood and brain tissue sampled between 1 and 3.5 min after a bolus injection of L-[1-11C] tyrosine. Radioactivity was measured every second in the blood and in 10-sec intervals in the brain tissue. In the normal controls the brain intransport rate constant for tyrosine was 0.052 ml/g/min with an influx rate of 2.97 nmol/g/min. The patients had a similar intransport rate constant (0.045 ml/g/min) but a lower influx rate of tyrosine 1.95 nmol/g/min (p less than 0.05). The patients' tyrosine concentrations in the blood were lower. For data sampled between 5 and 25 min, the net accumulation rate of tyrosine into the brain was 0.015 ml/g/min in the controls which did not differ to the patients' rate. However, the net utilization of tyrosine was lower in the patients (0.672 nmol/g/min) than in the controls (0.883 nmol/g/min) despite similar tissue concentrations of tyrosine.

Sonicated whole cells of one of three tested goncoccal strains stimulated neutrophil migration in the agarose gel model. The activity was retained by the material pelleted by high-speed centrifugation of the sonicate. This supports the theory that certain strains possess a cytotaxin bound to the outer membrane.