Binding studies of novel, non-mammalian enkephalins, structures predicted from frog and lungfish brain cDNA sequences

Leu- and Met-enkephalin were the first endogenous opioid peptides identified in different mammalian species including the human. Comparative biochemical and bioinformatic evidence indicates that enkephalins are not limited to mammals. Various prodynorphin (PDYN) sequences in lower vertebrates revealed the presence of other enkephalin fingerprints in these precursor polypeptides. Among the novel enkephalins Ile-enkephalin (Tyr-Gly-Gly-Phe-Ile) was primarily observed in the African clawed frog (Xenopus laevis) PDYNs, while the structure of Phe-enkephalin (Tyr-Gly-Gly-Phe-Phe) was predicted by analyzing brain cDNA sequences encoding a PDYN of the African lungfish (Protopterus annectens). Ile-enkephalin can also be found in the PDYNs of four other fish species including the eel, bichir, zebrafish and tilapia, but no further occurrence for the Phe-enkephalin motif is available as yet. Based on sequencing data, the biological relevance of Phe- and Ile-enkephalin is suggested, because both of them can arise by regular posttranslational enzymatic processing of the respective neuropeptide precursors. In various receptor binding assays performed on rat brain membrane preparations both of the new peptides turned out to be moderate affinity opioids with a weak preference for the delta-opioid receptor (DOP) sites. Phe-enkephalin of the lungfish displayed rather unexpectedly low affinities toward the mu-opioid receptor (MOP) and DOP, while exhibiting moderate affinity toward the kappa-opioid receptor (KOP). In receptor-mediated G-protein activation assays measured by the stimulation of [(35)S]GTPgammaS binding, Met-enkephalin produced the highest stimulation followed by Leu-enkephalin, Ile-enkephalin and Phe-enkephalin, whereas the least efficacious among these endogenous peptides was still more effective than the prototype opiate agonist morphine in these functional tests.

Caveolin-1 is transported to multi-vesicular bodies after albumin-induced endocytosis of caveolae in HepG2 cells

Caveolae-mediated endocytosis is a highly regulated endocytic pathway that exists in parallel to other forms of clathrin-dependent and -independent endocytosis. Internalized caveolae accumulate in intermediate organelles called caveosomes. Here we addressed the further fate of internalized caveolae by inducing caveolae-mediated uptake of albumin by HepG2 cells. We followed the route of internalized caveolin-1 by immunogold labelling of ultrathin frozen sections and by Western blot analyses of purified membrane fractions. Long-term (1 and 3 hrs) albumin treatment resulted in the appearance of albumin-containing caveolae in special multi-caveolar complexes (consisting of multiple caveolae clustered together) connected to the plasma membrane and caveosome-like structures in the cytoplasm. In addition, numerous CD63 (LIMP-1) positive late endosomes/multi-vesicular bodies were found positive for caveolin-1, suggesting that upon albumin incubation, caveolin-1 is endocytosed and enters the degradative pathway. Surprisingly, the number of caveolae at the plasma membrane increased after addition of albumin. This increase was blocked by cycloheximide treatment, indicating that albumin internalization also stimulates de novo protein synthesis, which is necessary for new caveolae formation. Together, our results show that during long-term albumin uptake, caveolin-1 travels to late endosomes and is replaced by newly synthesized caveolin-1 at the plasma membrane.

Oesophageal tonsil of the chicken

The oesophageal tonsil of the chicken is a novel member of the mucosal-associated lymphoid tissue (MALT), which is located around the entrance of the proventriculus. It consists of 6 to 8 single units, which are surrounded by a thin fibrous capsule. Each one is organised around the bottom of the longitudinal folds of the oesophagus, and serves as a 'tonsillar crypt'. Stratified squamous epithelium is infiltrated by lymphoid cells, i.e. T cells, plasma cells, macrophages, and dendritic cells, but not B cells, to form lymphoepithelium (LE). In the LE vimentin-, MHC II- and ATPase-positive cells possibly represent Langerhans' cells, but the appearance of 74.3 positive cells in the LE is unusual, because the 74.3 monoclonal antibody (mAb) recognises chicken follicular dendritic cells in the germinal centre and medulla of the bursal follicles. The subepithelial lymphoid tissue is organised into T- and B-dependent regions, which are the interfollicular areas and the germinal centres, respectively. Existence of high-endothelial venules in the interfollicular region suggests an extensive cellular connection between the oesophageal tonsil and the other lymphoid organs. In the resting oesophagus the lumen is closed, but during swallowing a bolus the crypt opens and the lymphoepithelium can be exposed to undigested food, antigens, infectious agents and vaccines. The location of the oesophageal tonsil, cranial to the stomach, may provide this organ with a unique role as compared to the other parts of the MALT; namely, it may contribute to the replication of infectious bursal disease virus (IBDV) and/or the pathogenesis of infectious bursal disease.

[Differentiation of parkinsonian and essential tremor using electrophysiological methods]

OBJECTIVE

Tremor is one of the most common movement disorders. Different tremors are induced by central and/or peripheral oscillators. The motor cortex plays a significant role in the generation of parkinsonian tremor but its function in essential tremor is not clear. We examined the effect of motor cortex activation on parkinsonian and essential tremor during movement of the contralateral hand. Our aim was to study the role of interhemispheric motor connections in genesis of different tremors.

PATIENTS AND METHODS

We recorded the tremor of nine Parkinson patients and seven patients suffering from essential tremor using accelerometry. After Fast Fourier-transformation of digitized tremor signal we measured the power changes at the peak frequency after flash triggered movement (FM) and self-paced movement (SPM). For control we used flash signal without movement.

RESULTS

Peak frequency of parkinsonian and essential tremor was not different. The power decrease of parkinsonian tremor was significant during flash triggered and self-paced movement compared to the effect of flash (p(Flash-FM)=0.0008; p(Flash-SPM)=0.002), changes during the different movement protocols were not different (p(FM-SPM)=0.33). During self-paced movement parkinsonian tremor became significantly smaller than essential tremor (p<0.05). The effect of movement was not significant on the power of essential tremor (p=0.42), probably due to high standard deviation of individual data.

CONCLUSIONS

Voluntary movement of the contralateral hand decreases parkinsonian tremor suggesting that its generator can be inhibited via the activation of the motor cortex. The diverse reaction of essential tremor may reflect various connections between its generator system and the motor areas, therefore it is not a separate disease entity.

Origin of the bursal secretory dendritic cell

The origin of vimentin-positive secretory dendritic cells of the bursa of Fabricius was studied by chick-quail chimera, parabiosis and immunohistochemistry using species-specific monoclonal antibodies. Quail bursal primordia of different ages were transferred to coelomic cavity of 3-day-old chicken embryos and further incubated for 18 days. In transplanted quail bursas the secretory dendritic cells of chicken and quail origin were detected by double staining of vimentin plus 74.3 and vimentin plus QCPN monoclonal antibodies, respectively. In bursal primordia of 5- and 6-day-old quail embryos both dendritic cells and B cells were of host, i.e. chicken origin. Mixed dendritic cell population of quail and chick origin emerged in chimeric birds of 6.5 days of age. In quail embryos transplanted at 7 and 8 days of age both dendritic cells and B cells were mixed i.e. of chicken and quail origin. Bursal secretory dendritic cells and medullary epithelial cells create "dendro-epithelial tissue" to receive pre-B cells. Colonization of dendro-epithelial tissue by pre-B cells initiates at day 7, thus the colonization of bursal anlage by blood-borne cells is a two-step process; entering of dendritic cells at day 6.5 is followed by that of B cells at day 7 and afterwards. It is discussed that bursal secretory dendritic cells and their product are key elements of bursal function therefore the mammalian bursa equivalent organ might be represented by a cell, which is analogous with the bursal secretory dendritic cell.

Esophageal tonsil: a novel gut-associated lymphoid organ

The esophageal tonsil of the chicken is a novel, significant element of the gut-associated lymphoid tissue (GALT). Its stable location and histological organization fulfills the meaning of the term "tonsil." The six-to-eight-isolated tonsillar units are located at the border of the esophagus and the proventriculus. The number of tonsillar units is identical with that of the esophageal folds. Each tonsillar unit consists of a crypt lined by lymphoepithelium and surrounded by dense lymphoid tissue, which is organized into T- and B-dependent regions, like peripheral lymphoid organs. The excretory ducts of the mucosal glands of the esophagus are frequently involved in the formation of the lymphoepithelium. The esophageal tonsil is anatomically located cranial to the stomach, unlike the other parts of the GALT. Therefore, it is continuously exposed to undigested environmental antigens, allergens, food, and infectious agents. To develop effective oral vaccines, the existence of the esophageal tonsil has to be taken into account.

Diverse expression of the K-1 antigen by cortico-medullary and reticular epithelial cells of the bursa of Fabricius in chicken and guinea fowl

The immunocytochemical study of the K-1 monoclonal antibody indicates that the epithelial components of the bursa of Fabricius of the chicken and guinea fowl express the K-1 positive molecule. During embryogenesis, the K-1 antigen expression appears together with the bud-formation. As the number of B cells increases in the developing follicle, the K-1 expression gradually diminishes in the medullary reticular epithelial cells and completely ceases by hatching, which suggests that the molecule is developmentally regulated. After hatching, the expression of the molecule is restricted to the sealing off zone of the lymphoepithelial or medullary region of the follicle: i.e. to the cortico-medullary (CM) epithelial cells and the follicle associated epithelium (FAE) supporting cells in guinea fowl and to the latter ones in the chicken. The expression of the K-1 antigen by these epithelial components may support their structural identity. After hatching, the K-1 molecule is restricted to the CM epithelial cells and/or FAE supporting cells, which suggests that the function of the embryonic epithelial bud is taken over by the CM epithelial cells. The K-1 positive CM epithelial cells form arches, which encompass blast-like cells. The possible relationship of the CM epithelial cells and blast-like cells, which may represent the precursors of bursal secretory dendritic cells is discussed.

Ontogeny of the dendritic, and follicle-associated epithelial cells in the bursa of Fabricius of guinea fowl (Numida meleagris)

A panel of monoclonal antibodies was produced to study the mesenchymal stromal elements of the bursa of Fabricius in guinea hen. The intracellular antigens recognized by GIIF3 and NIC2 monoclonal antibodies are of 50 and 30 kD, respectively. The cells identified by these antibodies emerge in the mesenchyme around day 12 of incubation, and immigrate into the surface epithelium of the bursal folds, which precedes the follicle formation. The GIIF3 cells move up to the luminal surface of the follicle and differentiate to follicle-associated epithelial cells. The NIC2 cells remain in the medulla, produce and secrete large amount NIC2 positive substance, when the bursal function starts up. The presence of double positive (GIIF3 and NIC2) cells in the medulla around hatching, seems to indicate, that the two cells might have a common origin. The NIC2 positive product of the bursal secretory dendritic cells contributes to the microenvironment, and possibly necessary for the B cell clonal expansion and establisment of the immune repertoire in the guinea hen.

Differential expression of GL7 activation antigen on bone marrow B cell subpopulations and peripheral B cells

GL7 was originally described as a 35-kDa late activation antigen on mouse T and B cells. GL7 expression has also been demonstrated on thymocytes, germinal center B cells and some neuronal cell types. Flow-cytometry and immunohistochemistry were used to follow changes in the expression of GL7 during B cell development, amongst B cell subpopulations and various anatomical locations. GL7 is expressed as early as the pro-B cell stage and increases up to the pre-B-I stadium. Expression remains high on pre-B-II and on immature B cells, although slightly decreases during maturation. GL7 is almost completely downregulated when IgD appears on the cell surface. On the periphery only a few B cells are positive and these cells are almost exclusively found in the sIgD- germinal center areas of lymph nodes and spleen. The staining pattern of GL7 is very similar to that of PNA in the lymph nodes but in the bone marrow we have found both B220+PNA+GL7- and B220+PNA+GL7+ populations, showing that GL7 and the antigen recognized by PNA are different. After in vitro stimulation, the GL7(hi) B cell population has also been found to be IgD negative. Functional comparison between in vitro activated and MACS sorted GL7(hi) and GL7(lo/-) spleen B cells of immunized mice showed significantly higher specific and total antibody production as well as antigen presenting capacity in the GL7(hi) population.

A novel monoclonal antibody identifies all avian embryonic myogenic cells and adult smooth muscle cells

A novel monoclonal antibody, designated GIIF3, recognized prospective and differentiated smooth muscle cells in avian species studied - guinea fowl, chicken and quail. The GIIF3 antigen appeared in the myocardial, and the myotomal cells of the embryos at Hamburger-Hamilton stages 10 and 14, respectively. The expression of the GIIF3 molecule in the vascular smooth muscle cells emerged in the ventral wall of the dorsal aorta at Hamburger-Hamilton stage 16. The visceral smooth muscle cells started to produce the GIIF3 molecule from Hamburger-Hamilton stage 28 onwards. In both cardiac and skeletal muscles the GIIF3 expression gradually diminished, and it was lost by the end of the embryonic period, unlike in the differentiated vascular and visceral smooth muscle cells. In the latter cells the GIIF3 immunoreactive product showed a fine granular pattern that accumulated in the central region of the cytoplasm; it also occurred in the nucleus. A heavily stained discontinuous layer was associated with the cell membrane. The immunoblotting of the GIIF3 antibody recognized protein bands at 50 and 42 kDa in lysates of adult avian gizzard. A detailed comparative immunohistochemical study was made by smooth muscle markers, which confirmed the results of the immunoblotting, namely, that the GIIF3 monoclonal antibody recognized an avian myogenic cell specific molecule. During smooth muscle cell differentiation the GIIF3 molecule appeared as early as the alpha-smooth muscle actin, and in adult birds continued to be expressed; therefore the GIIF3 molecule could be regarded as a novel avian smooth muscle specific marker.

Receptor constants for endomorphin-1 and endomorphin-1-ol indicate differences in efficacy and receptor occupancy

The opioid properties of endomorphin derivatives containing a C-terminal alcoholic(-ol) function were compared to the parent amidated compounds in isolated organs (longitudinal muscle strip of guinea-pig ileum and mouse vas deferens). Similar data were also generated for the mu-opioid receptor selective agonist synthetic peptide (D-Ala2, MePhe4, Gly5-ol)-enkephalin (DAMGO) and its Gly5-NH2 congener (DAMGA). Endomorphin-1-ol (Tyr-Pro-Trp-Phe-ol) had an IC50 of 80.6 nM in mouse vas deferens and 61.2 nM in guinea-pig ileum; the corresponding values for endomorphin-2-ol (Tyr-Pro-Phe-Phe-ol) were 49.6 and 48.2 nM, for DAMGO 59.8 and 29.2 nM, respectively. As it was indicated by the antagonism by naltrexone, the agonist actions were exerted exclusively at mu-opioid receptors in both organs. The -ol derivatives were slightly (2.3-4.3 times) less potent than the parent amides in the bioassays: all peptides had, apparently, full agonist properties in intact preparations. With the aim of revealing potential partial agonist properties among the investigated peptides, we partially inactivated the mu-opioid receptor pool in mouse vas deferens by 5x10(-7) M beta-funaltrexamine. The calculated receptor constants indicated a "high-affinity, low intrinsic efficacy" profile (i.e. a potential partial agonist property) for endomorphin-1, an intermediate character for endomorpin-1-ol and full agonism for DAMGA and DAMGO. Apparently, a higher receptor fraction remained accessible for endomorphin-1 (42.8%) than for the -ol congener (14.0%), DAMGO (20.2%) and DAMGA (14.1%) after partial inactivation.

Functional restoration of the bursa of Fabricius following in ovo infectious bursal disease vaccination

The primary role of the avian bursa of Fabricius is to provide an essential microenvironment for B-lymphocytes to diversify their immunoglobulin genes by gene hyperconversion. Infectious bursal disease (IBD) vaccination using intermediate plus vaccine strains can temporarily deplete the bursal follicles and interrupt the normal B-cell development, which is generally followed by B-cell repopulation and histological regeneration. To find evidence that functional restoration of the bursa of Fabricius occurs in addition to the histological regeneration, we have analysed the chB1 gene expression, which indicates active bursal B-lymphocytes, and also the surface expression of a carbohydrate structure Lewis(x), a marker which identifies those bursal B-lymphocytes that are undergoing gene hyperconversion. In ovo vaccination with an immune complex vaccine (IBDV-BDA) caused transient bursal destruction in both the SPF and the maternally protected broiler groups with differences evident in the starting time, the severity and the duration of the effect. After the depletion phase, signs of histological regeneration appeared together with chB1- and Lewis(x) expression indicating that B-lymphocytes were functionally active and the bursa of Fabricius was serving again as an efficient primary lymphoid organ providing an appropriate microenvironment for B-cell development.

Development of the follicle-associated epithelium and the secretory dendritic cell in the bursa of fabricius of the guinea fowl (Numida meleagris) studied by novel monoclonal antibodies

Two stromal elements, follicle-associated epithelium and secretory dendritic cells of the bursa of Fabricius were studied by light microscopy and two novel MAbs, that were produced against splenic cell suspensions of guinea fowls. Both antigens recognized by these MAbs, designated GIIF3 and NIC2, are localized in the cytoplasm of the stromal cells, and their molecular weights are 50 and 30 kD, respectively. During embryogenesis the GIIF3 and NIC2 cells emerge in the mesenchyme of the folds before follicle formation. The GIIF3 and the NIC2-positive cells accumulate under the surface epithelium of the plicae and migrate into the epithelium, that precedes the bud-formation. From the bud, the GIIF3-positive cells migrate up to the luminal surface, and they transform to distinct, highly polarized follicle-associated epithelial cells. Single GIIF3-positive cells are also present in the interfollicular epithelium. The NIC2 MAb recognized mesenchymal cells harbor in the lymphoepithelial compartment of the folliculus, and they elaborate cytoplasmic granules. Around Day 20 of embryogenesis large amount of NIC2-positive substance appear extracellularly in the medulla and around it. This period well correlates with the starting up of the bursal functions; clonal expansion of B cells, and generation of immune repertoire. After hatching the NIC2 stainability diminishes, and it is restricted to the medullary bursal secretory dendritic cells. The NIC2-positive, possibly elderly bursal secretory dendritic cells, are capable for migration into the follicle-associated epithelium. In eight-day old birds some cells of the follicle-associated epithelium reveals temporary NIC2 positivity, that may prove the transport of the follicle-associated epithelial cells into luminal direction. By 12 weeks of age the presence of NIC2-positive substance in the intercellular space of the FAE, rather than in the cells of FAE may indicate the termination of the transport of secretory substance. In conclusion, two types of mesenchymal cells enter the surface epithelium of the bursal folds. The GIIF3-positive cells appear on the luminal surface of the follicles and occupy the place of the follicle-associated epithelial cells. The NIC2-positive cells become secretory in nature and differentiate to bursal secretory dendritic cells. The follicle formation possibly, requires the joint presence of both GIIF3 and NIC2 cells in the epithelium.

Primary meningeal melanocytoma of the pineal region. Case report

A unique case of a meningeal melanocytoma located in the pineal region is presented. This 48-year-old man presented with a round pineal region tumor that caused triventricular hydrocephalus and exhibited slow clinical progression. During surgery a black encapsulated tumor was found and totally removed. On histopathological examination, the tumor proved to be a meningeal melanocytoma. In this report cell culture data are presented and the relevant literature is reviewed. The problems of histopathological diagnosis and management of patients with melanocytomas are also discussed.

Long-lasting antinociceptive effect of DAMGO chloromethyl ketone in rats

Previously, the opioid peptide Tyr-D-Ala-Gly-(NMe)Phe-CH2Cl (DAMCK) has been shown to bind irreversibly to mu opioid receptors in vitro. In the present work, the antinociceptive effect of DAMCK has been evaluated. Rats treated systemically with DAMCK (1-100 pg/kg) displayed a dose-dependent increase in tail-flick analgesia that peaked by 15 min, then stayed about the same until 60 min, followed by some decrease over time. Higher doses of DAMCK (10 ng/kg-100 microg/kg) produced a near-maximal antinociceptive effect that remained stable for 4 h. Significant antinociception was still detected 8 h, but not 24 h postinjection. In comparison, the parent peptide DAMGO (Tyr-D-Ala-Gly-(NMe)Phe-Gly-ol) reached maximal effect by about 30 min, followed by a rapid cessation of its antinociceptive response. Naloxone administered before DAMCK antagonized the antinociceptive response of DAMCK, indicating that it was mediated via opioid receptors. Naloxone administered 45 min after DAMCK attenuated the tail-flick response to some extent, but a substantial part (40-60% depending on the peptide concentration and evaluation time) remained unaffected. Central administration of DAMCK also elicited time- and concentration-dependent, profound, opioid receptor mediated, apparently irreversible antinociception.

Identifying the bicyclomycin binding domain through biochemical analysis of antibiotic-resistant rho proteins

Mutations M219K, S266A, and G337S in transcription termination factor Rho have been shown to confer resistance to the antibiotic bicyclomycin (BCM). All three His-tagged mutant Rho proteins exhibited similar Km values for ATP; however, the Vmax values at infinite ATP concentrations were one-fourth to one-third that for the His-tagged wild-type enzyme. BCM inhibition kinetics of poly(C)-dependent ATPase activity for the mutant proteins were non-competitive with respect to ATP (altering catalytic function but not ATP binding) and showed increased Ki values compared with His-tagged wild-type Rho. M219K and G337S exhibited increased ratios of poly(U)/poly(C)-stimulated ATPase activity and lower apparent Km values for ribo(C)10 in the poly(dC).ribo(C)10-dependent ATPase assay compared with His-tagged wild-type Rho. The S266A mutation did not show an increased poly(U)/poly(C) ATPase activity ratio and maintained approximately the same Km for ribo(C)10 in the poly(dC). ribo(C)10-dependent ATPase assay. The kinetic studies indicated that M219K and G337S altered the secondary RNA binding domain in Rho whereas the S266A mutation did not. Transcription termination assays for each mutant showed different patterns of Rho-terminated transcripts. Tyrosine substitution of Ser-266 led to BCM sensitivity intimating that an OH (hydroxyl) moiety at this position is needed for BCM (binding) inhibition. Our results suggest BCM binds to Rho at a site distinct from both the ATP and the primary RNA binding domains but close to the secondary RNA-binding (tracking) site and the ATP hydrolysis pocket.

Pancreatic pseudocysts associated with chronic pancreatitis--early and late results of 1367 operations

The authors hereby review the data of 1367 operations for pancreatic pseudocysts. The surgical procedures of choice in particular pancreatic pathologies are analysed in the light of early morbidity and mortality, as well as long term follow-up results. The best operations for pancreatic pseudocysts have been the internal drainage procedures, which resolve the pathological alterations without the necessity of pancreatic resection. The treatment of chronic pancreatitis may require combined surgical procedure, such as cysto-Wirsungo-gastrostomy. The pancreatic resections performed for the treatment of small pseudocysts in the pancreatic head have been superseded by the less invasive blunt, forced cysto-duodenostomies, representing better results secondary to the smaller perioperative risk for the patient. The cyst-to-stomach and cyst-to-duodenum internal drainage techniques are just as effective, but with shorter operation time, than the Roux-en-Y cysto-jejunostomies.