Ventricular volume and asymmetry in schizotypal personality disorder and schizophrenia assessed with magnetic resonance imaging

Magnetic resonance imaging (MRI) was performed in 12 patients with schizotypal personality disorder (SPD), 11 patients with chronic schizophrenia, and 23 age- and sex-matched normal volunteers. MRI slices were acquired in the axial plane at 1.2-mm intervals, and the ventricles were traced on every other slice. The lateral ventricular system was divided into the anterior horn, temporal horn, and dorsal lateral ventricle. Schizophrenic patients had larger left anterior and temporal horns than the normal volunteers. Size of the left anterior and temporal horn in SPD patients was intermediate between those of normal volunteers and schizophrenic patients and differed significantly from schizophrenic patients. The left-minus-right difference was larger in schizophrenic patients than in normal volunteers or SPD patients. Thus, in their structural brain characteristics, as well as in their clinical symptomatology, SPD patients evidence, in attenuated form, abnormalities resembling those found in full-fledged schizophrenia. The findings suggest that decreased left hemispheric volume, in frontal and temporal regions, may characterize both psychotic and non-psychotic disorders of the schizophrenia spectrum.

Stimulation of liver regeneration and function after partial hepatectomy in cirrhotic rats by continuous infusion of recombinant human hepatocyte growth factor

BACKGROUND/AIMS

Radical resection is accepted as one of the most curative treatments for hepatocellular carcinoma. However, most patients have coexisting cirrhosis and their liver function is usually impaired. It is therefore important to stimulate the regeneration and function of the remnant cirrhotic liver after hepatectomy. Hepatocyte growth factor is a potent mitogen that has been suggested to play a crucial role in liver regeneration.

METHODS

In this study, we performed 45% hepatectomy in rats with cirrhosis induced by thioacetamide, and administered recombinant human hepatocyte growth factor (rhHGF) with dextran sulfate by continuous infusion into the jugular vein with an infusion pump.

RESULTS

rhHGF stimulated an increase in the wet weight of the remnant liver compared with untreated control rats. The proliferating cell nuclear antigen labeling index showed that this increase resulted from the stimulation of DNA synthesis. Serum levels of liver enzymes increased after hepatectomy, but returned to the prehepatectomy level more rapidly in rhHGF-treated rats than in controls. rhHGF increased hepatic protein synthesis above prehepatectomy levels and also markedly increased the serum levels of hepatic lipid metabolites.

CONCLUSIONS

These results demonstrate that continuous intravenous infusion of rhHGF enhances the growth and function of the remnant liver in rats with cirrhosis after partial hepatectomy. Therefore, rhHGF may be useful after hepatic resection in patients with cirrhosis.

Mitogenic response and steroid sensitivity in MS lymphocytes

OBJECTIVES

We investigated mitogenic response and steroid sensitivity in multiple sclerosis (MS) lymphocytes to establish if MS lymphocytes were less steroid responsive.

MATERIAL AND METHODS

We compared mitogenic response to phytohaemagglutinin (PHA) and inhibition by dexamethasone (DEX) in circulating lymphocytes from both MS patients and healthy subjects.

RESULTS

We found a range of responses in each group but no significant differences between the two groups, nor in patients with and without enhancement on magnetic resonance imaging. The mid-inhibitory concentration of DEX in response to 1 microg/ml PHA was significantly lower than that for 2.5 microg/ml PHA in the patients. The mid-inhibitory concentrations of DEX in response to 2.5 microg/ml PHA negatively correlated with endogenous serum cortisol concentrations.

CONCLUSION

These data imply a spectrum of glucocorticoid response that is similar in normal and MS lymphocytes and can partly explain why response to steroid therapy is variable.

The neuroendocrine axis in patients with multiple sclerosis

We investigated the basal and dynamic regulation of the hypothalamo-pituitary-adrenal (HPA), hypothalamo-pituitary-thyroid (HPT) and hypothalamo-pituitary-gonadal axes and prolactin secretion in 52 patients with clinically definite multiple sclerosis. These patients also had gadolinium enhanced brain MRI scans and were divided into relapsing-remitting, secondary progressive and primary progressive subgroups. These subgroups were compared with healthy controls and a group of patients with other neurological diseases. The cortisol diurnal rhythm was preserved in all groups of patients. The time-integrated cortisol response to human corticotropin-releasing hormone (CRH) stimulation was lower in the patients with secondary progressive multiple sclerosis, compared with patients with primary progressive multiple sclerosis and healthy subjects. The time-integrated beta-endorphin response to CRH was greater in the patients with relapsing-remitting multiple sclerosis compared with the others. Feedback regulation assessed by dexamethasone suppression was normal. Serum testosterone was low in 24% of male multiple sclerosis patients and oestradiol was low in 25% of pre-menopausal female multiple sclerosis patients, whereas prolactin and the HPT function were normal. Correlations with C-reactive protein (CRP) and MRI suggest that activation of the HPA axis in multiple sclerosis patients is secondary to an active inflammatory stimulus.

Identification of the major casein kinase I phosphorylation sites on erythrocyte band 3

Human erythrocyte band 3 is a major substrate of two red blood cell protein kinases, casein kinase I and p72syk protein tyrosine kinase. Although the phosphorylation sites and physiologic consequences of p72syk phosphorylation have been characterized, little is known regarding casein kinase I phosphorylation. In this report, we identify the major phosphorylation site of casein kinase I. Using isolated components, casein kinase I was found to phosphorylate the cytoplasmic domain of band 3 (CDB3), primarily on Thr residues. Classical peptide mapping narrowed the major phosphorylation site to a peptide encompassing residues 24-91. Computer-assisted evaluation of this sequence not only showed two consensus casein kinase I phosphorylation sites, but also provided information on how to proteolytically separate and isolate the candidate sites. Following the suggested protocols, a heptapeptide containing the major phosphorylation site was isolated, subjected to amino acid sequencing, and found to be phosphorylated on Thr 42. A minor phosphorylation site was similarly identified as Ser 303. Because Thr 42 is situated near the binding sites on CDB3 of ankyrin, protein 4.1, protein 4.2, and the glycolytic enzymes, phosphorylation of CDB3 by casein kinase I could conceivably impact erythrocyte structure and/or function.

Resistance of actin to cleavage during apoptosis

A small number of cellular proteins present in the nucleus, cytosol, and membrane fraction are specifically cleaved by the interleukin-1beta-converting enzyme (ICE)-like family of proteases during apoptosis. Previous results have demonstrated that one of these, the cytoskeletal protein actin, is degraded in rat PC12 pheochromocytoma cells upon serum withdrawal. Extracts from etoposide-treated U937 cells are also capable of cleaving actin. It was assumed that cleavage of actin represented a general phenomenon, and a mechanism coordinating proteolytic, endonucleolytic, and morphological aspects of apoptosis was proposed. We demonstrate here that actin is resistant to degradation in several different human cells induced to undergo apoptosis in response to a variety of stimuli, including Fas ligation, serum withdrawal, cytotoxic T-cell killing, and DNA damage. On the other hand, cell-free extracts from these cells and the ICE-like protease CPP32 were capable of cleaving actin in vitro. We conclude that while actin contains cleavage sites for ICE-like proteases, it is not degraded in vivo in human cells either because of lack of access of these proteases to actin or due to the presence of other factors that prevent degradation.

Probing the stability of class I major histocompatibility complex (MHC) molecules on the surface of human cells

We used binding of a fluorescent adduct of beta2-microglobulin, fluorescein beta2m, to probe the stability of class I HLA molecules on the surface of human cells. The weight of the literature suggests that this ligand binds to heavy chains that have lost beta2m and possibly peptide as well. Hence Fl-beta2m reports on the stability of the class I HLA trimer. A small fraction of HLA molecules, approximately 5%, binds Fl-beta2m on both resting and activated T cells. A larger fraction of all HLA molecules binds Fl-beta2m in FO-1 cells, beta2m-deficient cells, transfected with various B2m genes. HLA molecules of FO-1 cells are more stable when expressed with human beta2m, than when expressed with mouse beta2m. The non-covalent association of HLA heavy chains, beta2m and peptide implies that eventually every molecule of HLA trimer ought to dissociate and bind Fl-beta2m. In fact, the extent of exchange is limited by the lifetime of a given molecule at the cell surface. beta2m exchange decreases as cell concentration increases, suggesting that some density-dependent process acts to enhance degradation or denaturation of beta2m-free HLA heavy chains.

Reduced IL-10 secretion by CD4+ T lymphocytes expressing mutant cystic fibrosis transmembrane conductance regulator (CFTR)

Expression of the CFTR protein is thought to be physiologically important only in exocrine epithelial cells. However, chronic respiratory inflammation and infection remain unexplained phenomena in disease pathogenesis. Non-transformed, antigen-responsive CD4+ T cells cloned from healthy controls and CF patients homozygous or heterozygous for the delta F508 mutation transcribed CFTR mRNA and expressed immunoreactive cytoplasmic CFTR protein. T cell clones (TCC) from controls and CF patients displayed equivalent Ca(2+)-mediated Cl- current; however, TCC from patients with CF but not controls displayed defective cAMP-mediated Cl-current. Although CF-derived TCC preserved mitogen and antigen proliferative responses and specificity to tetanus toxoid epitopes, they selectively secreted approximately 45% less IL-10 compared with control TCC after activation with concanavalin A (Con A) (624 +/- 101 versus 1564 +/- 401 pg/ml per 10(6) cells, respectively; P = 0.04) or anti-CD3/phorbol ester (5148 +/- 1634 versus 11788 +/- 2390 pg/ml; P = 0.05). This difference was independent of atopy. Secretion of interferon-gamma, IL-2, and IL-4 was comparable in CF and control TCC after both forms of activation, while IL-5 was reduced in CF TCC following anti-CD3/phorbol myristate acetate (PMA) but not after Con A. We conclude that expression of mutant CFTR in human TCC is accompanied by ion channel dysfunction characteristic of the CF phenotype, and is accompanied by a reduction in IL-10 secretion after polyclonal activation. It is possible that disruption of IL-10-mediated anti-inflammatory homeostasis may contribute to early onset sustained inflammation in CF airways.

Interaction of the IciA protein with AT-rich regions in plasmid replication origins

A set of AT-rich repeats is a common motif in prokaryotic replication origins. We have screened for proteins binding to the AT-rich repeat region in plasmids F, R1 and pSC101 using an electrophoretic mobility shift assay with PCR-amplified DNA fragments from the origins. The IciA protein, which is known to bind to the AT-rich repeat region in the Escherichia coli origin of chromosome replication, oriC, was found to bind to the corresponding region from plasmids F (oriS) and R1, but not to pSC101. DNase I footprint analysis showed that IciA interacted with the AT-rich region in both F and R1. When the IciA gene was deleted, the copy number of plasmid F increased somewhat, whereas there was no major effect on the replication of pSC101 and R1, or on the E. coli chromosome.

Structure and characterization of a putative drought-inducible H1 histone gene

A drought- and abscisic acid (ABA)-inducible gene, His1, was isolated from Lycopersicon pennellii, a drought-resistant relative of cultivated tomato, and the gene structure was defined experimentally. The nucleotide sequence of His1 predicts a protein of 202 amino acid residues, with a significant sequence homology to plant H1 histones. Consensus sequences for both H1 histone-specific promoter elements as well as an ABA-responsive element were identified in the 5'-flanking region of His1. Transcripts of this gene accumulate in leaf tissue in response to drought in three tomato species including cultivated tomato (L. esculentum), L. pennellii, and L. chilense, as well as in tobacco. Transcripts for His1 are constitutively expressed in roots; transcript abundances in tomato root tips were equivalent to transcript abundances in more mature regions of the seedling root. The accumulation in leaves of transcripts for His1 preceded visible symptoms of drought stress in the plants. Transcript accumulation was detected in both drought-sensitive and drought-resistant species at similar leaf water potentials, psi W -1.3 to -1.4 MPa.

[Clinical and experimental study on composite wuzi dihuang liquor in treating male infertility]

Composite Wuzi Dihuang Liquor (CWDL) in treating male infertility was used. The results showed that the effective rate was 84%. CWDL is indicated in mild and medium idiopathic oligozoospermia. There was some effect in the male infertility which was complicated by prostatitis, varicocele, antisperm antibody positive patients, but was ineffective in severe oligozoospermia, azoospermia, tesicular volume 15ml, endocrinologic and chromatic abnormality. Experimental study revealed that the drug could significantly increase the percentage of reproductivity in mice and could directly safeguard the sperm of male infertility patients.

Luminescence quenching by long range electron transfer: a probe of protein clustering and conformation at the cell surface

Quenching of luminescence from fluorescent and phosphorescent probes by nitroxide spin labels with a long range electron transfer (LRET) mechanism (44,45) has been tested as a tool to monitor association/clustering and conformational changes of cell surface proteins. The membrane proteins were labeled with monoclonal antibodies or Fab fragments conjugated with luminescent probes or water-soluble nitroxide spin labels. The method was tested as a probe of 3 different aspects of protein-protein association involving class I MHC molecules: (1) interaction between the heavy and light chains of the MHC molecules, (2) clustering, self-association of MHC molecules, (3) proximity of MHC molecules to transferrin receptors of fibroblasts or surface immunoglobulin molecules of B lymphoblasts. The extent of quenching upon increasing the fractional density of the quencher was sensitive for protein association in accordance with earlier immunoprecipitation and flow cytometric Förster-type energy transfer (FCET) data obtained on the same cells. These data suggest that the LRET quenching can be used as intra- or intermolecular ruler in a 0.5-2.5 nm distance range. This approach is simpler (measurements only on donor side) and faster than many other experimental techniques in screening physical association or conformational changes of membrane proteins by means of spectrofluorimetry, flow cytometry, or microscope based imaging.

Analysis of the structure of empty and peptide-loaded major histocompatibility complex molecules at the cell surface

We compared the conformation of empty and peptide-loaded class I major histocompatibility complex (MHC) molecules at the cell surface. Molecular conformations were analyzed by fluorescence resonance energy transfer (FRET) between fluorescent-labeled Fab fragments bound to the alpha 2 domain of the MHC heavy chain and fluorescent-labeled Fab fragments bound to beta 2-microglobulin. No FRET was found between Fab fragments bound to empty H-2Kb, but FRET was detected when empty H-2Kb molecules were loaded with peptide. The magnitude of FRET depended on the sequence of the peptide used. The results imply that empty H-2Kb molecules are in a relatively extended conformation, and that this conformation becomes more compact when peptide is bound. These changes, which are reflected in peptide-dependent binding of monoclonal antibodies, affect the surfaces of MHC molecules available for contact with T cell receptors and hence may influence T cell-receptor recognition of MHC molecules.

Mutation of the alpha 2 domain disulfide bridge of the class I molecule HLA-A*0201. Effect on maturation and peptide presentation

A combination of saturation and site-directed mutagenesis was utilized to disrupt the alpha 2 domain disulfide bridge of HLA-A*0201. Mutation of cysteine 101 to a serine (C101S) or of cysteine 164 to alanine (C164A) decreased the rate of maturation of the heavy chain, the total amount of mature heavy chain within the cell, and the level of surface expression. Cells expressing these genes and loaded with a synthetic peptide derived from the influenza A matrix protein (58-66) were recognized poorly by HLA-A*0201-restricted, peptide-specific CTLs. Cells expressing mutant HLA-A*0201 loaded with a synthetic peptide derived from the HIV-1 pol protein (476-484) were not recognized by pol IV-9-specific CTLs. Mutant C164A cells infected with influenza virus were partially recognized by influenza matrix peptide-specific CTLs, while C101S cells were not lysed. Surprisingly, endogenous peptide loading of cells expressing mutant HLA-A*0201 using a minigene coding for either the influenza A matrix peptide 58-66, or HIV-1 pol peptide 476-484, resulted in efficient CTL recognition. This suggests different structural constraints for peptide binding in the endoplasmic reticulum during biosynthesis and for binding to exported molecules on the cells surface.

Clustering of class I HLA molecules on the surfaces of activated and transformed human cells

We surveyed cells for the clusters of class I HLA molecules, HLA-I, which we have previously found on JY lymphoblasts. Two fluorescence techniques, fluorescence resonance energy transfer and electron exchange quenching, detected clustered HLA-I molecules on activated normal B and T cells, on cells of B and T lymphoblast lines, and on transformed fibroblasts. No HLA-I clusters were detectable in the surfaces of resting B or T cells or normal fibroblasts. HLA clustering correlates perfectly with the presence of the HC-10 epitope of beta 2-microglobulin (beta 2m)-free heavy chains at the cell surface although not with the amount of this epitope expressed. Clustering was reversed by exogenous beta 2m, but this did not change the amount of HC-10 bound. This suggests that a form of beta 2m-free heavy chain in equilibrium with both native HLA molecules and fully denatured HC-10-positive heavy chains is involved in HLA-I cluster formation.

Clustering of class I HLA molecules on the surfaces of activated and transformed human cells

We surveyed cells for the clusters of class I HLA molecules, HLA-I, which we have previously found on JY lymphoblasts. Two fluorescence techniques, fluorescence resonance energy transfer and electron exchange quenching, detected clustered HLA-I molecules on activated normal B and T cells, on cells of B and T lymphoblast lines, and on transformed fibroblasts. No HLA-I clusters were detectable in the surfaces of resting B or T cells or normal fibroblasts. HLA clustering correlates perfectly with the presence of the HC-10 epitope of beta 2-microglobulin (beta 2m)-free heavy chains at the cell surface although not with the amount of this epitope expressed. Clustering was reversed by exogenous beta 2m, but this did not change the amount of HC-10 bound. This suggests that a form of beta 2m-free heavy chain in equilibrium with both native HLA molecules and fully denatured HC-10-positive heavy chains is involved in HLA-I cluster formation.

Human erythrocyte casein kinase II: characterization and phosphorylation of membrane cytoskeletal proteins

Casein kinase II activities were purified from human erythrocyte membrane and cytosolic fractions to apparent homogeneity. The kinases isolated from the membrane and cytosolic fractions exhibited the same subunit composition and the ability to utilize ATP and GTP as phosphoryl donors. Antibodies against the alpha and alpha' subunits of human casein kinase II cross reacted with the corresponding subunits of both erythrocyte casein kinases. Spermine, spermidine, putrescine, and polylysine stimulated to varying degrees the activities of erythrocyte casein kinase II, whereas heparin inhibited the kinase activities. Both kinases were found to catalyze the phosphorylation of several erythrocyte membrane cytoskeletal proteins, including spectrin, ankyrin, adducin, protein 4.1, and protein 4.9. Unlike casein kinase I, casein kinase II did not phosphorylate band 3 appreciably. A preliminary estimate indicates that both human erythrocyte membrane and cytosolic casein kinase II catalyze the incorporation of approximately 1.2 and 3.5 moles of phosphate into each mole of spectrin and ankyrin, respectively. An analysis of the phosphopeptide maps of ankyrin indicates that both membrane and cytosolic kinases phosphorylate the same domains within ankyrin. These data, taken together, suggest that the type II casein kinases isolated from human erythrocyte membrane and cytosol are either identical or closely related and may play a role in the regulation of cytoskeletal protein interactions.

Identity and substrate specificity of human erythrocyte membrane-bound and cytosolic casein kinases

The relationship and substrate specificity of the human erythrocyte membrane kinase and casein kinase A were investigated. Based on Staphylococcus aureus V8 protease digestion patterns, the 2 kinases appeared to be structurally homologous. These enzymes also exhibited the same substrate specificity and phosphorylated the same synthetic peptides and domains of ankyrin. Both kinases did not utilize GTP effectively as a substrate and were not inhibited by low concentrations of heparin, suggesting that they were type I casein kinases. An analysis of synthetic peptide phosphorylation failed to reveal a specific pattern of recognition of the amino acid sequence surrounding the phosphorylation site.

Comparative analysis of the replication regions of IncB, IncK, and IncZ plasmids

Minireplicons from the I-complex plasmids R387 (IncK) and pIE545 (IncZ) were constructed, and the nucleotide sequences of their replication regions were compared with that of the B plasmid, pMU720. The coding sequence of the putative replication protein, RepA, of each plasmid was located. RepA of K and B plasmids were homologous, whereas RepA of Z resembled RepA1 of FII plasmid. Sequences upstream of RepA were conserved in the three I-complex plasmids. Group B and Z plasmids were incompatible.

Genetics of mouse hepatitis virus transcription: identification of cistrons which may function in positive and negative strand RNA synthesis

A panel of 26 temperature-sensitive mutants of MHV-A59 were selected by mutagenesis with either 5-fluorouracil or 5-azacytidine. Complementation analysis revealed the presence of one RNA+ and five RNA- complementation groups. None of the RNA- complementation groups transcribed detectable levels of positive- or negative-stranded RNA at the restrictive temperature. Temperature shift experiments after the onset of mRNA synthesis revealed at least two classes of RNA- mutants. RNA- complementation groups A, B, D, and E were blocked in the ability to release infectious virus and transcribe mRNA and genome, while group C mutants continued to release infectious virus and transcribe both mRNA and genome. Temperature shift experiments at different times postinfection suggest that the group C mutants encode a function required early in viral transcription which affects the overall rate of positive strand synthesis. Analysis of steady state levels of negative strand RNA after the shift indicate that the group C mutants were probably blocked in the ability to synthesize additional minus strand RNA under conditions in which the group E mutants continued low levels of minus strand synthesis. These data suggest that at least four cistrons may be required for positive strand synthesis while the group C cistron functions during minus strand synthesis.

Lateral diffusion of H-2 antigens on mouse fibroblasts

We have used fluorescence photobleaching and recovery (FPR) to measure the lateral diffusion of mouse H-2 antigens, labeled with fluorescent Fab fragments, in the membrane of cl 1d fibroblasts. Diffusion coefficients, D, vary more than 20-fold from cell to cell, though they vary no more than twofold when measured at different points on a single cell. The fraction of H-2 antigens mobile, R, also varies from cell to cell, and no lateral diffusion of H-2 antigens can be detected in approximately 20% of the cells examined. Treatment of cells with NaCN + NaF, reducing their levels of ATP reduces the proportion of cells in which no lateral diffusion can be detected. The maximum values of D seen in poisoned cells are less than those in controls. Treatment of cells with the divalent inophore, A23187, greatly increases the proportion of cells in which diffusion of H-2 is rapid, D greater than 2 x 10(-9) cm2 s-1. The data obtained on diffusion by FPR can be replotted in the form of an experiment in which lateral diffusion of H-2 antigens is measured in a population of heterokaryons. There is good agreement between this transformation and actual data on heterokaryons. Thus the two methods appear to measure the same transport process.