Neuropeptide Y induced feeding in the rat is mediated by a novel receptor

There are now six recognized neuropeptide Y (NPY) receptor subtypes (Y1-Y4 and two recently cloned distinct receptors labeled Y5), of which Y1 and one of the Y5's have been suggested could mediate the effect of NPY on feeding. The fragments NPY(2-36) and NPY(3-36), which bind Y1 only poorly, were injected intracerebroventricularly (icv) and found to have similar dose-response relationships to NPY in the stimulation of feeding. However NPY (13-36), which stimulates both Y2 and Y5, caused no increase in food intake, even at high doses. Maximal stimulation with the classical Y1 agonist [Pro34]-NPY produced only 50% of the maximum effect of NPY itself despite fully inhibiting adenylyl cyclase activity in vitro in a Y1 system. The novel fragment [Pro34]-NPY(3-36) is as effective at stimulating food intake as the classical Y1 analogue [Pro34]-NPY but bound to the Y1 receptor with only 1/20th of the affinity of NPY and failed to inhibit adenylyl cyclase through this receptor. [Pro34]-NPY(3-36) is therefore a relatively appetite-selective ligand. Coadministration of high dose NPY(13-36) and [Pro34]NPY did not enhance feeding compared with [Pro34]-NPY alone. In addition, the NPY Y1 receptor antagonist BIBP-3226, which does not bind Y2, Y4, or Y5 receptors, significantly reduced NPY induced feeding. These results indicate that the feeding effect of icv NPY involves a novel receptor and that it is functionally distinct from the recognized receptor subtypes.

Chromosome painting of radiation-induced micronuclei

In this report, in situ hybridization with whole chromosome painting probes was used to paint radiation-induced micronuclei (MN) in three lymphoblastoid cells lines to investigate the frequency of radiation-induced MN. The results obtained for four different chromosomes showed that there was a significant deviation of the numbers of signal-positive MN from that expected on the basis of DNA proportionality. Restriction of the analysis to three chromosomes showed that the deviations arose primarily from chromosome 7, which was underrepresented in the numbers of signal-positive MN in the group of chromosomes studied.

Adrenomedullin inhibits feeding in the rat by a mechanism involving calcitonin gene-related peptide receptors

The central effect of adrenomedullin on feeding was investigated in fasted rats. After intracerebroventricular administration, adrenomedullin decreased 2-h food intake in a dose-dependent manner. A dose of 1.7 nmol adrenomedullin decreased 2-h food intake by 57%. Adrenomedullin shares sequence homology with calcitonin gene-related peptide (CGRP), a central anorectic agent, and binding sites for both are present in the hypothalamus. Adrenomedullin competed for [125I]adrenomedullin- and [125I]CGRP-binding sites in hypothalamic membranes. The Kd for the [125I]adrenomedullin-binding site was 0.54 +/- 0.07 nM, with a binding capacity of 214 +/- 27 fmol/mg membrane protein (n = 3). CGRP and the CGRP receptor antagonist CGRP-(8-37) at concentrations up to 1 microM did not compete at these sites. The Kd for the CGRP-binding site was 0.10 +/- 0.02 nM, with a binding capacity of 250 +/- 31 fmol/mg, and the Ki values for adrenomedullin and CGRP-(8-37) were 4.6 +/- 2.1 and 4.0 +/- 1.6 nM, respectively (n = 3). Thus, adrenomedullin showed high affinity binding at both adrenomedullin- and CGRP-binding sites. To establish whether adrenomedullin reduces feeding via CGRP receptors, we coadministered adrenomedullin (1.7 nmol) and CGRP-(8-37) (30 nmol). The reduction in 2-h food intake induced by adrenomedullin was 50% inhibited by CGRP-(8-37). These results show that adrenomedullin decreases food intake in the rat, and this effect is mediated at least in part via CGRP receptors.

Increased frequency of HLA-DPB1*0301 in Hodgkin's disease suggests that susceptibility is HVR-sequence and subtype-associated

Hodgkin's disease (HD) is a complex lymphoma-like disease which occurs as four main subtypes, nodular sclerosing (NS), mixed cellularity (MC), lymphocyte predominant (LP) and lymphocyte depleted (LD). Suggestions from epidemiological studies that HD may represent an unusual response to infection imply that the lack of previous response could be due to genetic factors. Following recent reports suggesting that there is an increased frequency of HLA-DPB1*0301 in Hodgkins disease, we have studied DPB1 in two series of patients using molecular typing methods. One series is a retrospective group of 118 patients over the age of 15 years from a single centre, and the other is a multi-centre prospective group of 45 patients between the age of 16 and 24 years. In both series, the percentage of HD patients with DPB1*0301 is greater than in the controls, confirming that this seems to be an HD-susceptibility allele. However, extension of the analysis in relation to HD subtype shows that the increase in *0301 is present in nodular sclerosing (NS), mixed cellularity (MC) and lymphocyte predominant patients (LP) HD patients, but preliminary evidence suggests an increase in *0401, and possibly *0501 in MC- and LP-HD. The DPB1 hypervariable region (HVR) amino-acid motif Asp55, Glu56 (*0301-like, HVR-C) is increased in NS compared with non-NS (ie MC+LP), whereas the frequency of Ala55, Ala56 (*0401-like) is increased in non-NS compared with NS. Conversely, Asp84, Glu85Ala86(*0301-like, HVR-F) motif is more frequent in NS than non-NS patients, but there is no increase in Gly84, Gly855, Pro86 (*0401-like). These findings suggest that genetic susceptibility in HD may reside at the level of HVR-encoded DPB1 peptide-binding residues, rather than with a specific allele, and that this may in some way influence the HD subtype.

Specific adrenomedullin binding sites and hypotension in the rat systemic vascular bed

The potent vasodilator peptide, adrenomedullin, has been shown to be present in plasma, suggesting a physiological role in cardiovascular control. Here we investigated the hypotensive action of adrenomedullin in vivo, using the anaesthetised rat as the bioassay model, and adrenomedullin binding sites using ligand binding assays on rat blood vessel membranes. Rat alpha CGRP and both human and rat adrenomedullins induced dose-dependent, powerful and long-lasting hypotensive effects. At peptide doses used in this study (0.02-2 nmol/kg), the efficacy of both human and rat adrenomedullins was lower than that of rat alpha CGRP. The CGRP1-receptor antagonist, human CGRP(8-37) (200 nmol/kg) was able to completely inhibit the hypotensive effect of rat alpha CGRP (0.2 nmol/kg) but not that of rat adrenomedullin (2 nmol/kg), implying that the adrenomedullin action is independent of CGRP1-receptors. Ligand binding assays confirmed the presence of both CGRP and adrenomedullin binding sites in rat blood vessels. The 125I-rat adrenomedullin binding site has a Kd = 0.32 +/- 0.12 nM (n = 4) for rat adrenomedullin but has a Ki > 10(-6) M for rat alpha CGRP. Chemical cross-linking and SDS-PAGE analysis revealed theadrenomedullin binding protein to have a M(r) of 83000 with a minor band of M(r) = 99000. The results suggest that the hypotensive effect of adrenomedullin may be mediated via specific adrenomedullin binding sites, in vivo.

Molecular analysis of HLA-DQB1 alleles in childhood common acute lymphoblastic leukaemia

Epidemiological studies suggest that childhood common acute lymphoblastic leukaemia (c-ALL) may be the rare outcome of early post-natal infection with a common infectious agent. One of the factors that may determine whether a child succumbs to c-ALL is how it responds to the candidate infection. Since immune responses to infection are under the partial control of (human leucocyte antigen) HLA genes, an association between an HLA allele and c-ALL could provide support for an infectious aetiology. To define the limit of c-ALL susceptibility within the HLA region, we have compared HLA-DQB1 allele frequencies in a cohort of 62 children with c-ALL with 76 newborn controls, using group-specific polymerase chain reaction (PCR) amplification, and single-strand conformation polymorphism (SSCP) analysis. We find that a significant excess of children with c-ALL type for DQB1*05 [relative risk (RR): 2.54, uncorrected P=0.038], and a marginal excess with DQB1*0501 (RR: 2.18; P=0.095). Only 3 of the 62 children with c-ALL have the other susceptibility allele, DPB1*0201 as well as DQB1*0501, whereas 15 had one or the other allele. This suggests that HLA-associated susceptibility may be determined independently by at least two loci, and is not due to linkage disequilibrium. The combined relative risk of the two groups of children with DPB1*0201 and/or DQB1*0501 is 2.76 (P=0.0076). Analysis of amino acids encoded by exon 2 of DQB1 reveal additional complexity, with significant (P<0.05) or borderline-significant increases in Gly26, His30, Val57, Glu66-Val67 encoding motifs in c-ALL compared with controls. Since these amino acids are not restricted to DQB1*0501, our results suggest that, as with DPB1, the increased risk of c-ALL associated with DQB1 is determined by specific amino acid encoding motifs rather than by an individual allele. These results also suggest that HLA-associated susceptibility to c-ALL may not be restricted to the region bounded by DPB1 and DQB1.

A role for glucagon-like peptide-1 in the central regulation of feeding

The sequence of glucagon-like peptide-1 (7-36) amide (GLP-1) is completely conserved in all mammalian species studied, implying that it plays a critical physiological role. We have shown that GLP-1 and its specific receptors are present in the hypothalamus. No physiological role for central GLP-1 has been established. We report here that intracerebroventricular (ICV) GLP-1 powerfully inhibits feeding in fasted rats. ICV injection of the specific GLP-1-receptor antagonist, exendin (9-39), blocked the inhibitory effect of GLP-1 on food intake. Exendin (9-39) alone had no influence on fast-induced feeding but more than doubled food intake in satiated rats, and augmented the feeding response to the appetite stimulant, neuropeptide Y. Induction of c-fos is a marker of neuronal activation. Following ICV GLP-1 injection, c-fos appeared exclusively in the paraventricular nucleus of the hypothalamus and central nucleus of the amygdala, and this was inhibited by prior administration of exendin (9-39). Both of these regions of the brain are of primary importance in the regulation of feeding. These findings suggest that central GLP-1 is a new physiological mediator of satiety.

Infantile osteopetrosis; bone marrow transplantation from a cousin donor

The successful correction of infantile osteopetrosis in an Asian child by bone marrow transplantation (BMT) from an HLA-A,B matched cousin donor is reported. Retrospective HLA molecular analysis revealed that patient and donor were incompatible for HLA-DPB1. Donor type cells detected in the patient after transplantation indicate successful engraftment. The patient is currently alive and well.

Micronucleus frequencies in lymphoblastoid cell lines measured with the cytokinesis-block technique and flow cytometry

In these experiments, the cytokinesis-block technique was used to measure the spontaneous and radiation-induced micronucleus frequencies in lymphoblastoid cell lines from normal individuals and individuals with radiation-sensitive syndromes. The radiation-induced micronucleus frequencies were measured at different harvest times to investigate the optimum time to measure radiation-induced cytogenetic damage with the cytokinesis-block technique. The frequency of radiation-induced micronuclei was found to be independent of the frequency of binucleate cells in these cell lines. Longer incubation times were complicated by increasing numbers of mononucleate and multinucleate cells, and scoring slides at an early incubation time after the maximum frequency of binucleate cells is reached was recommended. Two of the cell lines (one established from an individual with ataxia telangiectasia, and one from an infant with mitotic instability) had significantly higher radiation-induced micronucleus frequencies than the control cell lines. Finally, the radiation-induced micronucleus frequencies in three of the cell lines were measured by flow cytometry, and the results ranked the cell lines in the same order of radiosensitivity as the cytokinesis block technique.

Definition of the blepharophimosis, ptosis, epicanthus inversus syndrome critical region at chromosome 3q23 based on the analysis of chromosomal anomalies

Blepharophimosis syndrome (BPES) is an autosomal dominant disorder of craniofacial development, the features of which are small palpebral fissures (blepharophimosis), drooping eyelids (ptosis) and a skin fold arising from the lower eyelid (epicanthus inversus). The chromosomal localization and identity of the BPES locus is not known with certainty. In the current paper, DNA samples from three individuals with a clinical history of BPES, two with interstitial deletions (cases 1 and 2) and one with a balanced translocation (case 3) all involving chromosome 3q23, were analyzed. Allele loss studies using short tandem repeat markers in cases 1 and 2 suggested that the region between the markers D3S1292 and D3S1306 was deleted in both cases. Subsequently, the derived chromosomes resulting from the translocation in case 3 were segregated in interspecific somatic cell hybrids. Analysis of the resultant hybrids showed that D3S1615 was retained in the derived chromosome 3, whereas D3S1316 was retained in the derived chromosome 4. In neither case was the marker present in the reciprocal hybrid. These results indicate that the BPES critical region lies in the D3S1615-D3S1316 interval.

Molecular genetic analysis of a family with a history of Hodgkin's disease and dyschondrosteosis

We describe a family in which two sisters with the autosomal dominant skeletal dysplasia, Leri-Weill dyschondrosteosis (LWD), developed Hodgkin's disease (HD) in late adolescence. In a preliminary attempt to identify HD susceptibility gene(s), HLA-typing and linkage analysis were carried out in the family. Using HLA molecular typing, both sisters were found to have inherited a variant of the HD-susceptibility allele, DPB1*0301, known as DPB1*2001. Following a previous report of a constitutional chromosome translocation (t(2q;8p)) in a family with LWD, preliminary linkage studies were carried out using chromosome 2q and 8p molecular markers. Regions covered by 7/10 chromosome 2 markers and 4/8 chromosome 8 markers were excluded as the location of a candidate LWD gene. Given the rarity of LWD and HD, their simultaneous occurrence is unlikely to have been due to chance. We suggest that a mutation in the LWD gene itself, or a gene closely linked to it, perhaps acting with increased susceptibility to infection conferred by DPB1*2001, resulted in HD in the two sisters.

Enhanced expression of type 1 procollagen and transforming growth factor-beta in tuberculin induced delayed type hypersensitivity

AIMS

Tissue fibrosis is a common and serious consequence of chronic inflammation. The mechanism linking these two processes is poorly understood. The present study has utilised a human in vivo model of a delayed type hypersensitivity (DTH) reaction, the tuberculin Heaf reaction, induced by intradermal tuberculin in BCG immunised subjects, to dissect the relation between these two processes.

METHODS

Punch skin biopsy specimens were obtained on day 5, day 13 and six to 16 weeks following the tuberculin Heaf test in 18 subjects with grade 3 or 4 responses. Skin biopsy specimens from six subjects served as controls. The specimens were examined using immunohistochemical staining for type 1 procollagen and transforming growth factor-beta (TGF-beta), as well as in situ hybridisation for type 1 procollagen messenger RNA (mRNA).

RESULTS

Immunohistochemical analysis revealed increased deposition of TGF-beta in tissue matrix in the biopsy specimens obtained on day 5 following the tuberculin Heaf test. There was also extensive type 1 procollagen staining in the biopsy specimens obtained as early as day 5. Procollagen-1 staining was maximal on day 13, and was present in biopsy specimens from tuberculin Heaf test sites up to eight weeks after the tuberculin inoculation. The type 1 procollagen was localised within cells surrounding areas of inflammatory infiltrate and in perivascular tissues. The presence of new collagen formation was confirmed by in situ hybridisation using oligonucleotide probes for type 1 procollagen mRNA in cells in sections from biopsy specimens obtained on day 13.

CONCLUSIONS

These data from a human in vivo model of a DTH response indicate that the immune response is intimately associated with an increase in the production of growth factors and the initiation of a fibrotic response.

Preliminary evidence of an association between HLA-DPB1*0201 and childhood common acute lymphoblastic leukaemia supports an infectious aetiology

It has been suggested that childhood leukaemia may be the abnormal outcome of a common infection. Rare events caused by common environmental events such as infections are likely to be influenced by host genetic susceptibility. We have therefore investigated whether immunogenetic susceptibility contributes to the risk of childhood common ALL (c-ALL). In this preliminary study, we report that children with c-ALL (n = 63) carry the HLA-DPB1 locus allele *0201 twice and nearly three times more frequently than adult (n = 92; relative risk (RR) = 2.9, P < 0.05) or infant controls (n = 82; RR = 2.1). Moreover, children with c-ALL are 3-4 times more likely than controls to be heterozygous for DPB1*0201/*0301, /*0401 and /*0402 (RRadult controls = 3.9; RRinfant controls = 2.8). These results suggest that HLA-DPB1*0201 either alone or with other DPB1 alleles contributes to the risk of childhood c-ALL, possibly by increasing susceptibility to an infectious agent.

Molecular characterization of leukocyte adhesion deficiency in six patients

Leukocyte adhesion deficiency (LAD) is caused by defects in the CD18 gene, which codes for the common beta 2 subunit of the leukocyte integrins LFA-1, Mac-1 and p150,95. Failure to produce a functional beta 2 subunit results in the defective expression of all three leukocyte integrins, and the leukocytes of LAD patients have subnormal adhesion properties. Six patients with LAD were studied. Patient B was homozygous and carried a G284S mutation. A two-bp (GA) deletion at position 1256 (1256 delta GA) was found in the cDNA of patient C, who also had an abnormally large mRNA of 4.3 kb. Patients E and K were siblings and were heterozygous at the genomic level. One defective allele contained a mutation in intron 6/7 which created a preemptive 3' splice site. The resulting mRNA has 12 extra bases at the junction of exons 6 and 7, coding for four extra residues PSSQ in the protein. The same allele also carried a R586W mutation. The other allele was transcribed at a low level and was not characterized. Patient G carried a L149P mutation in one allele; again, the other allele was not characterized due to low transcription levels. Patient R carried two mutant alleles with G284S and R593C mutations respectively. The G284S mutation and the 1256 delta GA deletion have not been reported previously. CD18 cDNA carrying the abnormalities were cotransfected with normal CD11a or CD11b cDNA into COS cells. Expression of the LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) antigens on COS cells was not detected, suggesting that these two mutations are sufficient to account for LAD.

Brain regions and encephalization in anurans: adaptation or stability?

Relative brain size and the relative size of six brain regions (main olfactory bulbs, accessory olfactory bulbs, telencephalon, optic tectum, cerebellum and brain stem) in ten species of anurans from five habitats were examined to determine whether there was any evidence of adaptation in brain structure. A previously published data set was also reanalysed. Arboreal frogs have larger body-size corrected brains than frogs from other habitats. Arboreal ranid (Platymantis vitiensis) and hylid (Hyla versicolor) possess slightly larger cerebella than the ranids and hylids from other habitats. Platymantis vitiensis lacks an accessory olfactory bulb. The fully-aquatic Xenopus laevis (Pipidae) has a smaller optic tectum and cerebellum than the non-fossorial hylids and ranids. Adaptation to life underground appears to explain the modified brains of two fossorial frogs, Hemisus guineensis (Ranidae) and Rhinophrynus dorsalis (Rhinophrynidae). Both species of fossorial frogs have reduced optic tecta, larger main olfactory and smaller accessory olfactory bulbs, and larger torus semicircularis than non-fossorial species. Our data showed a strong negative correlation between the size of the optic tectum and the size of the main olfactory bulbs. We conclude that, although anuran brains are very similar across taxa in qualitative and general structure, there are some interesting, apparent adaptations, to fossorial and arboreal life.

Cellular localization of inducible nitric oxide synthase in experimental endotoxic shock in the rat

1. Endotoxin induces a shock-like syndrome with increased nitric oxide synthesis. To clarify the cellular source of NO in endotoxic shock we used immunohistochemistry and in situ hybridization to localize inducible NO synthase in rats given lipopolysaccharide or Corynebacterium parvum and lipopolysaccharide. Immunohistochemistry was carried out with an antibody raised against a synthetic peptide of mouse macrophage NO synthase. In situ hybridization was performed with 35S-labelled oligonucleotide probes corresponding to cDNA sequences common to mouse macrophage inducible NO synthase and rat vascular smooth inducible NO synthase. Monocytes and macrophages were identified by immunohistochemistry with the mouse monoclonal antibody ED1. 2. After lipopolysaccharide alone, the major site of NO synthase induction was monocytes and macrophages in multiple organs, principally liver and spleen. Bronchial, bile duct, intestinal and bladder epithelium and some hepatocytes also expressed inducible NO synthase. Expression peaked at 5 h and had returned to normal by 12 h except in spleen. 3. After priming with C. parvum, lipopolysaccharide led to a similar distribution of inducible NO synthase as lipopolysaccharide alone, but in addition there was more prominent hepatocyte staining, staining in macrophage granulomas in the liver and inducible NO synthase was present in some endothelial cells in the aorta. 4. These findings provide a direct demonstration of the cellular localization of inducible NO synthase after lipopolysaccharide.

Interleukin-1 beta gene expression in experimental glomerulonephritis in the rat: an in-situ hybridization study

To investigate the role of interleukin-1 beta (IL-1 beta) in glomerulonephritis we studied the presence of IL-1 beta by in-situ hybridization in in-situ immune complex glomerulonephritis in the rat. Glomerulonephritis was induced in preimmunized rats by unilateral renal perfusion with cationized human IgG. In-situ hybridization was performed on frozen sections with a battery of four 30mer oligonucleotide DNA probes 3' end labelled with 35S-dATP. IL-1 beta mRNA was detectable in nephritic glomeruli at 6 and 24 hours after induction of glomerulonephritis. Signal was maximal at 48 hours and markedly reduced by 4 days. The peak of IL-1 beta transcription coincided with the major monocyte influx into glomeruli consistent with a role for IL-1 beta as a mediator of glomerular hypercellularity.

Induction of nitric oxide synthase in rat immune complex glomerulonephritis

Nitric oxide (NO) is a biological mediator which is synthesized from L-arginine by a family of nitric oxide synthases (NOS). Previously we have shown that NO is synthesized ex vivo by glomeruli obtained from animals with acute immune complex glomerulonephritis. We have now sought evidence for the in vivo induction of NOS in glomeruli by immunohistochemistry using specific antisera raised against a peptide sequence of inducible mouse macrophage NOS and by in situ hybridization. The expression of the enzyme was studied in kidneys of rats with acute unilateral immune complex glomerulonephritis, induced by cationized IgG, by immunohistochemistry. Inducible NOS (iNOS) was present in glomeruli in nephritic (left) kidneys at the time of maximum macrophage infiltration, both within intraglomerular mononuclear cells and cells emigrating into Bowman's space. iNOS expressing cells were also present in interstitial infiltrates. There was no expression in normal rat kidneys or in glomeruli in the non-nephritic (right) kidneys of experimental rats. In situ hybridization confirmed the immunohistochemical localization. These results provide the first direct evidence for the presence and localization of inducible NOS in glomeruli and support a significant role for NO in the pathogenesis of immune complex glomerulonephritis.

HLA class I non-coding nucleotide sequences, 1992

We present a compilation of the nucleotide sequences of the non-coding regions of the human HLA class I genes which complements previously published information on exon sequences. The listing includes the 5' and 3' untranslated (UT) regions, and introns 1-7. The HLA class I loci and their alleles from which non-coding sequences were derived are listed in Table 1, together with source references. Where possible, locus and allele designations follow the Nomenclature for factors of the HLA system 1991 (Bodmer et al., 1992). In aligning sequences, nucleotides which are conserved between all class I genes are specified only by the consensus sequence, and are indicated by a hyphen (-). To maintain the alignment between different alleles, an asterisk (*) is inserted where there is a gap in the sequence. An unavailable sequence is indicated by a period (.). Regions of sequence too diverse to be accurately compared are represented by an exclamation mark (!). Sequence motifs previously classified as having an important role in HLA class I regulation or processing, such as enhancer sequences, are identified at the bottom of the sequence comparison. It is not our intention in this paper to present an analysis of the many features revealed by this compilation. However, we hope that the information will provide important reference material for studies of HLA class I mRNA processing (Cianetti et al., 1989), promoter regulation (David-Watine et al., 1990) and in the design of allele, locus or region specific PCR primers (Summers et al., 1991). We hope to update this compilation in due course, and we would welcome sequence information not included in this publication, as well as comments and corrections that help to maintain the accuracy of the information.