Secretion of the trefoil factor TFF3 from the isolated vascularly perfused rat colon

The trefoil factor TFF3 is a peptide predominantly produced by mucus-secreting cells in the small and large intestines. It has been implicated in intestinal protection and repair. The mechanisms that govern TFF3 secretion are poorly understood. The aim of this study was, therefore, to evaluate the influence of neurotransmitters, hormonal peptides and mediators of inflammation on the release of TFF3. For this purpose, an isolated vascularly perfused rat colon preparation was used. After a bolus administration of 1 ml isotonic saline into the lumen, TFF3 secretion was induced by a 30-min intra-arterial infusion of the compounds to be tested. TFF3 was evaluated in the luminal effluent using a newly developed radioimmunoassay. TFF3 was barely detected in crude luminal samples. In contrast, dithiothreitol (DTT) treatment of the effluent revealed TFF3 immunoreactivity, which amounted to about 0.3 pmol min(-1) cm(-1) in the basal state. Gel chromatography of DTT-treated luminal samples revealed a single peak that co-eluted with the monomeric form of TFF3. TFF3 was not detected in the portal effluent. Bethanechol (10(-6)-10(-4) M), vasoactive intestinal peptide (VIP, 10(-8)-10(-7) M) or bombesin (10(-8)-10(-7) M) induced a dose-dependent release of TFF3. In contrast, substance P evoked a modest release of TFF3, whereas calcitonin gene-related peptide (CGRP), somatostatin, neurotensin or peptide YY (PYY) did not modify TFF3 secretion. The degranulator compound bromolasalocid, 16,16-dimethyl PGE2 (dmPGE2) or interleukin-1-beta (IL-1-beta) also evoked a marked release of TFF3. In conclusion, TFF3 in the colonic effluent is present in a complex. This association presumably involves a disulfide bond. Additionally, the present results suggest a role for enteric nervous system and resident immune cells in mediation of colonic TFF3 secretion.

Modular structure of the TIM23 preprotein translocase of mitochondria

The TIM23 complex mediates import into mitochondria of nuclear encoded preproteins with a matrix-targeting signal. It is composed of the integral membrane proteins Tim17 and Tim23 and the peripheral membrane protein Tim44, which recruits mitochondrial Hsp70 to the sites of protein import. We have analyzed the functions of these constituents using a combined genetic and biochemical approach. Depletion of either Tim17 or Tim23 led to loss of import competence of mitochondria and to a reduction in the number of preprotein-conducting channels. Upon depletion of Tim44, mitochondria also lost their ability to import proteins but maintained normal numbers of import channels. In the absence of Tim44 precursor protein was specifically recognized. The presequence was translocated in a Delta psi-dependent manner across the inner membrane and cleaved by matrix-processing peptidase. However, the preprotein did not move further into the matrix but rather underwent retrograde sliding out of the TIM23 complex. Thus, the TIM23 complex is composed of functionally independent modules. Tim17 and Tim23 are necessary for initiating translocation, whereas Tim44 and mitochondrial Hsp70 are indispensable for complete transport of preproteins and for unfolding of folded domains of preproteins.

Defective nuclear localization of p53 protein in a Chinese hamster cell line is associated with the formation of stable cytoplasmic protein multimers in cells with gene amplification

Many p53 functions require p53 transport into the nucleus. Mutant p53 also generally accumulates in the nucleus of transformed or neoplastic cells. However, examples of cytoplasmic accumulation of wild-type or mutant p53 have also been reported. Various explanations have been provided for defective nuclear localization. Here we propose a novel example of cytoplasmic p53 localization which occurs in cells showing gene amplification and appears to be due to the formation of stable p53 multimers. We studied a methotrexate-resistant Chinese hamster cell line (MTX M) carrying amplified dihydrofolate reductase genes and derived from a cell line with p53 nuclear accumulation. MTX M showed cytoplasmic p53 localization and, on immunoblots, several extra bands in the high molecular weight region, besides the expected 53 kDa band. p53 localization and the appearance of high molecular weight bands appeared to be correlated with the degree of DNA amplification. However, amplification of dihydrofolate reductase itself was not involved. Changing the p53 phosphorylation status quantitatively influenced the formation of high molecular weight bands. Cell fusion experiments demonstrated that p53 cytoplasmic localization in MTX M is a dominant phenotype. This result suggests that the defect causing lack of nuclear localization in this cell line does not reside in the nucleus. In the cytoplasm of MTX M and of wild-type/MTX M heterodikaryons p53 gives rise to protein complexes that are unable to re-enter the nucleus. The formation of such protein complexes is dependent on the amplification of an unknown gene product.

New benzodiazepines alter acetylcholinesterase and ATPDase activities

This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats. Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose. The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4(p-methyl-phenyl)-3H- 1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 0.01) when tested in the range of 0.18-0.35 mM. The inhibition caused by these two new benzodiazepines was noncompetitive in nature. Similarly, at concentrations ranging from 0.063 to 0.25 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 0.01). However, the inhibition of nucleotide hydrolysis was uncompetitive in nature. Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities.

Release of guanylin immunoreactivity from the isolated vascularly perfused rat colon

The intestinal peptide guanylin regulates the electrolyte/water transport in the intestinal epithelium. The aim of the present study was to investigate the mechanisms that modulate its secretion in the isolated vascularly perfused rat colon by using a specific guanylin RIA. Intraarterial infusion of bethanechol (10(-4) M) or bombesin (10(-7) M) elicited a significant 6-fold increase in the release of guanylin immunoreactivity (G-IR) in the lumen. Bombesin-stimulated G-IR secretion was strongly reduced by tetrodotoxin, whereas atropine had no effect. VIP (10(-7) M) induced a moderate release of G-IR, whereas substance P, calcitonin gene-related peptide, peptide YY, somatostatin, and neurotensin were without effect. Dimethyl-PGE2 (1.4 x 10(-5) M) or interleukin-1beta (2.5 x 10(-10) M) induced a 3-fold increase in G-IR in the lumen, whereas the degranulator compound bromolasalocid did not stimulate guanylin secretion. Forskolin (10(-5) M) or sodium nitroprusside (10(-4)-10(-3) M) induced a significant release of G-IR. In contrast, PMA (10(-7) M) or ionophore A23187 (10(-6) M) did not modify basal secretion of G-IR. Upon stimulation of guanylin release with bombesin or bethanechol, an increase in G-IR in the portal effluent was also detected. The release of G-IR in the portal effluent was 40-fold lower than that of G-IR into the luminal perfusate. Additionally, analysis with gel chromatography revealed that the immunoreactive material released in the lumen or in the portal effluent coeluted with the 15-amino acid peptide originally isolated from rat intestine. In conclusion, the present data suggest that the enteric nervous system and immune cells may modulate guanylin release from the rat colon. The release of guanylin in the lumen and portal effluent suggests that this peptide may exert both luminal/paracrine and hormonal effects.

[Chromatin remodeling in estrogen-dependent and independent human breast cancer cell lines]

Chromatin restricts the accessibility of DNA to regulatory factors; its remodeling over the regulatory regions contributes to the control of gene expression. An increasing number of evidence links defects in chromatin remodeling machinery and cancer. Our aim is to elucidate the role of chromatin structure in the control of the expression of hormone-induced genes in breast cell lines estrogen-dependent or -independent for growth. Mammary tumor growth is controlled by steroid hormones via their nuclear receptor and by growth factors via tyrosine kinase receptors. 50 % of these tumors elude to hormonal control. This limits the anti-estrogen therapy. As a model, we have analyzed in several cell lines the chromatin organization of the regulatory regions of two genes, pS2 that is associated with a good prognostic, and cathepsin D (catD) that is a bad prognostic marker. The expression of the two genes is estrogen-regulated in estrogen-dependent cell line MCF7. In contrast in the hormone-independent cell line MDA MB 231, pS2 is not expressed and catD is constitutively expressed. Within the regulatory regions of pS2 gene, we have localized two regions that undergo a hormone-dependent change in chromatin structure in MCF7 cells but not in MDA MB 231. The lack of chromatin remodeling in MDA MB 231 cells is not due to the absence of expression of the estrogen receptor in the cell line. The expression of pS2 gene can be correlated with chromatin remodeling over the regulatory regions of pS2 gene. In contrast catD regulatory regions did not display hormone-dependent changes in chromatin structure, suggesting that hormone regulation takes place within regions with a constitutively open chromatin structure.

Individual and combined effect of granulocyte-macrophage colony-stimulating factor and prolactin on maturation of dendritic cells from blood monocytes under serum-free conditions

Prolactin (PRL) shares structural and functional features with haemopoietic factors and cytokine peptides. Dendritic cells (DC) are involved in both initiating the primary and boosting the secondary host immune response and can be differentiated in vitro from precursors under the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) plus other factors. Because PRL has been shown to functionally interact with GM-CSF, we have addressed its role on GM-CSF-driven differentiation of DC. Monocytic DC precursors from peripheral blood mononuclear cells (PBMC) were enriched either by adhesion to a plastic surface or CD14-positive selection and cultured for 7 days in serum-free medium containing GM-CSF, interleukin (IL)-4 and PRL, alone or in combination. Cells with large, veiled cytoplasm, expressing major histocompatibility complex (MHC) class II and the costimulatory molecules CD80, CD86 and CD40 and lacking the monocyte marker CD14, were considered as having the phenotype of cytokine-generated DC. Functional maturation was assessed by proliferation and interferon-gamma (IFN-gamma) release of allogeneic T lymphocytes. Physiological (10-20 ng/ml) concentrations of PRL interacted synergistically with GM-CSF and the effect was similar to that induced by IL-4 on GM-CSF-driven DC maturation. When used alone, the physiological concentrations of PRL were inhibitory, whereas higher concentrations (80 ng/ml) were stimulatory. The synergistic effect of PRL may in part be caused by its ability to counteract the down-modulation of the GM-CSF receptor observed in serum-free conditions. These data provide further evidence of the significance of PRL in the process of T lymphocyte activation.

Mucin secretion is modulated by luminal factors in the isolated vascularly perfused rat colon

BACKGROUND

Mucins play an important protective role in the colonic mucosa. Luminal factors modulating colonic mucus release have been not fully identified.

AIM

To determine the effect of some dietary compounds on mucus discharge in rat colon.

METHODS

An isolated vascularly perfused rat colon model was used. Mucus secretion was induced by a variety of luminal factors administered as a bolus of 1 ml for 30 minutes in the colonic loop. Mucin release was evaluated using a sandwich enzyme linked immunosorbent assay supported by histological analysis.

RESULTS

The three dietary fibres tested in this study (pectin, gum arabic, and cellulose) did not provoke mucus secretion. Luminal administration of sodium alginate (an algal polysaccharide used as a food additive) or ulvan (a sulphated algal polymer) induced a dose dependent increase in mucin discharge over the concentration range 1-25 mg/l (p<0.05 for 25 mg/l alginate and p<0.05 for 10 and 25 mg/l ulvan). Glucuronic acid and galacturonic acid, which are major constituents of a variety of fibres, produced significant mucin secretion (p<0.05). Hydrogen sulphide and mercaptoacetate, two sulphides produced in the colonic lumen by microbial fermentation of sulphated polysaccharides, did not modify mucin secretion. Among the short chain fatty acids, acetate (5-100 mM) induced a dose dependent release of mucus (p<0.05 for 100 mM acetate). Interestingly, butyrate at a concentration of 5 mM produced colonic mucin secretion (p<0.05), but increasing its concentration to 100 mM provoked a gradual decrease in mucus discharge. Propionate (5-100 mM) did not induce mucin release. Several dietary phenolic compounds (quercetin, epicatechin, resveratrol) did not provoke mucus discharge.

CONCLUSIONS

Two algal polysaccharides (alginate and ulvan), two uronic acids (glucuronic acid and galacturonic acid), and the short chain fatty acids acetate and butyrate induce mucin secretion in rat colon. Taken together, these data suggest that some food constituents and their fermentation products may regulate the secretory function of colonic goblet cells.

Characterization of ATP and DNA binding activities of TrwB, the coupling protein essential in plasmid R388 conjugation

TrwB is the conjugative coupling protein of plasmid R388. TrwBDeltaN70 contains the soluble domain of TrwB. It was constructed by deletion of trwB sequences containing TrwB N-proximal transmembrane segments. Purified TrwBDeltaN70 protein bound tightly the fluorescent ATP analogue TNP-ATP (K(s) = 8.7 microM) but did not show measurable ATPase or GTPase activity. A single ATP binding site was found per TrwB monomer. An intact ATP-binding site was essential for R388 conjugation, since a TrwB mutant with a single amino acid alteration in the ATP-binding signature (K136T) was transfer-deficient. TrwBDeltaN70 also bound DNA nonspecifically. DNA binding enhanced TrwC nic cleavage, providing the first evidence that directly links TrwB with conjugative DNA processing. Since DNA bound by TrwBDeltaN70 also showed increased negative superhelicity (as shown by increased sensitivity to topoisomerase I), nic cleavage enhancement was assumed to be a consequence of the increased single-stranded nature of DNA around nic. The mutant protein TrwB(K136T)DeltaN70 was indistinguishable from TrwBDeltaN70 with respect to the above properties, indicating that TrwB ATP binding activity is not required for them. The reported properties of TrwB suggest potential functions for conjugative coupling proteins, both as triggers of conjugative DNA processing and as motors in the transport process.

[Tumor samples as a tool for large-scale monitoring of antigen-specific lymphocytes in gastric and colorectal neoplasms]

The characterization of tumor-associated antigens has enabled to direct the host immune response towards the autologous tumor through appropriate loading and presentation of the antigen. In vivo conditions that generate large numbers of tumor antigens would be an important step in vaccine strategies. In this study we have therefore tested the ability of freshly isolated gastric and colorectal cancer cells to induce a specific anti-tumor response in autologous T lymphocytes. Because dendritic cells (DC) are critically involved in both initiating and boosting host immune responses, they have been used to present apoptotic bodies generated by irradiated tumor cells. Results show that these native antigens stimulate T cytotoxic response against tumor, but not peritumor normal tissues. Induction of IFN-gamma secreting cell activity, which is a standard readout in current cancer vaccine protocols, was also demonstrated by Elispot single-cells assay. These data show the antigenicity of gastric and colorectal tumor cells and open new perspectives in immunotherapy.

The TIM17.23 preprotein translocase of mitochondria: composition and function in protein transport into the matrix

We have analysed the structural organization of the TIM17.23 complex, the preprotein translocase of the mitochondrial inner membrane specific for protein targeting to the matrix. The components Tim17, Tim23 and Tim44 are present in this complex in equimolar amounts. A sub-complex containing Tim23 and Tim44 but no Tim17, or a sub-complex containing Tim23 and Tim17 but no Tim44 was not detected. Tim44 is peripherally associated at the matrix side. Tim44 forms dimers which recruit two molecules of mt-Hsp70 to the sites of protein import. A sequential, hand-over-hand mode of interaction of these two mt-Hsp70.Tim44 complexes with a translocating polypeptide chain is proposed.

Derivative chromosome 17 in a case of Burkitt lymphoma with 8;14 translocation

A complex chromosome rearrangement present in a B-cell line established from a patient with Burkitt lymphoma was studied by using fluorescence in situ hybridization (FISH) and immunocytochemistry techniques. The rearranged chromosome (der17) was apparently composed of 17q, of a partially deleted 17p, and of other material of chromosome 17p origin that was interspersed with regions without any clear banding pattern. der(17) contained a functional ch17 centromere and two additional centromeres of unknown origin that were inactive by all evidence. By FISH analysis with a TP53 probe, a signal could be demonstrated on the normal ch17, but not on the rearranged chromosome, a finding which indicates that 17p deletion caused a concurrent loss of one of the two TP53 alleles. The marker chromosome was previously observed in some of the malignant cells obtained from the patient's peripheral blood. These observations therefore indicate that cells with this specific rearrangement were generated in vivo and subsequently selected. This rearrangement is likely to have conferred a selective growth advantage to a subclone present in the original malignant cell population.

Intracellular levels of the LIS1 protein correlate with clinical and neuroradiological findings in patients with classical lissencephaly

We report on the genotype-phenotype correlation in 7 patients with classical lissencephaly carrying a heterozygous subtle mutation in the LIS1 gene. Six patients, showed a mutation predicted to encode for a truncated protein, and one mutation altered a splicing site, resulting in skipping of exon 4. Western blot analysis performed on the lymphoblastoid cell line of 2 patients bearing truncating mutations indicated that the mutated allele did not produce a detectable amount of the LIS1 protein; whereas the analysis performed on the fibroblasts from the patient with a splice-site mutation was suggestive of partial protein synthesis from the mutated allele. Although clinical and magnetic resonance imaging findings of patients with truncating mutations did not differ from those observed in patients with a heterozygous deletion, the patient bearing the exon-skipping mutation had less severe clinical and brain involvement. Our data suggest that truncating mutations in the LIS1 gene are relatively common among patients with classical lissencephaly not bearing a heterozygous deletion at 17p13.3, and strengthen the relevance of correct intracellular dosage of the LIS1 protein in the neuronal migration process.

Effects of neurotransmitters, gut hormones, and inflammatory mediators on mucus discharge in rat colon

The effect of potential mediators of mucus secretion was investigated in the isolated vascularly perfused rat colon by using a sandwich enzyme-linked immunosorbent assay for rat colonic mucin and by histochemical analysis. Bethanechol (100-200 microM), bombesin (100 nM), and vasoactive intestinal peptide (VIP, 100 nM) provoked a dramatic mucin discharge (maximal response at 900, 900, and 600% of control loops, respectively). VIP-stimulated mucin secretion was abolished by tetrodotoxin, whereas atropine was without effect. In contrast, both tetrodotoxin and atropine significantly decreased mucin release induced by bombesin. Isoproterenol or calcitonin gene-related peptide was without effect. Serotonin (1-5 microM) and peptide YY (10 nM) evoked mucin discharge, whereas glucagon-like peptide-1 did not release mucin. Finally, bromolasalocid (20 microM), interleukin-1beta (0.25 nM), sodium nitroprusside (1 mM), and dimethyl-PGE2 (2.5 microM) induced mucus discharge. The results demonstrated a good correlation between the immunological method and histological analysis. In conclusion, these findings suggest a role for the enteric nervous system, the enteroendocrine cells, and resident immune cells in mediation of colonic mucus release.

Peptide YY, glucagon-like peptide-1, and neurotensin responses to luminal factors in the isolated vascularly perfused rat ileum

Exposure of the ileum to nutrients markedly inhibits several upper gastrointestinal functions. Hormonal peptides of the ileal wall, i.e. peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and neurotensin (NT), are thought to play a role in this negative feedback mechanism. The present study was conducted to comparatively assess the secretion of PYY, GLP-1, and NT upon luminal infusion of a variety of individual luminal factors in the isolated vascularly perfused rat ileum preparation. PYY, GLP-1, and NT were measured in the portal effluent with specific RIAs. Glucose (250 mM) induced a pronounced release of the three peptides, whereas a physiological concentration of 5 mM did not induce peptide secretion. Peptone (5%, wt/vol) evoked a sustained release of PYY, GLP-1, and NT. Only NT secretion was increased upon luminal administration of 100 mM sodium oleate. Short chain fatty acids (20 mM) evoked an early and transient release of the three peptides. In contrast, taurocholate (20 mM) induced a sustained release of PYY, GLP-1, and NT, but the threshold concentration for peptide release was lower for NT than for PYY or GLP-1. Cellulose or pectin (0.5%, wt/vol) did not modify peptide secretion. In conclusion, glucose and peptone are potent stimulants of PYY, GLP-1, and NT release. Only NT is released upon oleic acid stimulation. Finally, taurocholate is a potent stimulant of the release of the three peptides. Overall, PYY, GLP-1, and NT may participate cooperatively in the ileal brake. As relatively high concentrations of the various stimulants were required to elicit peptide release, it seems likely that this mechanism operates in cases of maldigestion or malabsorption.

Presymptomatic detection of familial juvenile hyperuricaemic nephropathy in children

We studied 34 apparently healthy children and 2 propositi from kindreds with familial juvenile hyperuricaemic nephropathy (FJHN) - a disorder characterised by early onset, hyperuricaemia, gout, familial renal disease and a similarly low urate clearance relative to glomerular filtration rate (GFR) [fractional excretion of uric acid (FEur) 5.1+/-1.6%] in young men and women. In addition to the propositi, 17 asymptomatic children were hyperuricaemic -- mean plasma urate (368+/-30 micromol/l), twice that of controls (154+/-41 micromol/l). Eight of them had a normal GFR ( > 80 ml/min per 1.73 m2), and 11 renal dysfunction, which was severe in 5. The FEur in the 14 hyperuricaemic children with a GFR > 50 ml/min was 5.0+/-0.5% and in the 5 with a GFR < or =50 ml/min was still low (11.5+/-0.2%) compared with controls (18.4+/-5.1%). The 17 normouricaemic children (185+/-37 micromol/l) had a normal GFR (>80 ml/min) and FEur (14.0+/-5.3%). The results highlight the dominant inheritance, absence of the usual child/adult difference in FEur in FJHN and presence of hyperuricaemia without renal disease in 42% of affected children, but not vice versa. Since early allopurinol treatment may retard progression to end-stage renal failure, screening of all relatives in FJHN kindreds is essential.

Eyelid basal cell carcinoma with intracranial extension

We describe a case of basal cell carcinoma (BCC) situated on the external upper margin of the right eyelid in a young man aged 28 years. The tumor was diagnosed as an "extended wart in a degenerative phase" and removed during reconstructive plastic surgery. No pathologic examination was performed. Seven years later, the operation was followed by a first recurrence. Pathologic examination was then performed, and the diagnosis was BCC. Therapy was with radiotherapy and chemotherapy. Subsequent recurrences were treated with radiotherapy and surgery (enucleation, exenteration of the orbit), but the evolution of the tumor was not halted. It ended 25 years after its first manifestation with the death of the patient of a hemorrhage of the upper airways during an operation, the aim of which was to reexamine the orbital cavity. The autopsy revealed intracranial extension of the tumor, and all the histological examinations confirmed the diagnosis. No histopathological feature was found that could differentiate a particularly aggressive nature of the tumor. Basal cell carcinoma is a tumor more frequently encountered in elderly patients. Its appearance in a young subject may cause grounds for suspicion, requiring initial radical surgical treatment and careful surveillance of the evolution of the lesion. This case documents the fatal consequences that may arise from the failure to recognize BCC in its first manifestation and highlights the ineffectiveness of repeated radiation and surgical therapy against continual recurrence.

Heterogeneous p53 mutations in a Burkitt lymphoma from an AIDS patient with monoclonal c-myc and VDJ rearrangements

This study investigates the timing of p53 mutations detected in the malignant cells of a Burkitt's lymphoma cell line (BRG-P) with respect to other maturation or transforming events. The BRG-P cell line, derived from an AIDS patient, was of special value since it displayed subclones that had undergone an isotype switch from IgM to IgA1 (BRG-M and BRG-A cells). BRG-M and BRG-A cells were characterized by the same monoclonal c-myc and VDJ rearrangements and by the expression of Ig receptors with specificity for a 45 kDa protein of human breast cells. Analysis of p53 mutations in the different BRG subclones showed that 1) BRG-M cells displayed 2 different p53 mutations in trans; since the original BL cells also showed the same mutations, this finding indicated that both occurred in vivo; 2) one of the p53 alleles of BRG-A cells was lost, while the other showed a mutation different from those seen in BRG-M cells; and 3) all 3 mutations observed in BRG-M or BRG-A cells resulted in the functional inactivation of the transcriptional activation function of p53. Together, our data demonstrate that p53 mutations were relatively late events during lymphomagenesis. Moreover, in view of the role of p53 in cell apoptosis, it is conceivable that BRG cells were subjected to a strong selective pressure that favored p53 inactivation. Such inactivation was possibly required to counterbalance other potentially apoptotic events, including the presence of a deregulated c-myc oncogene and signals delivered by the host environment in situ.

Activation of Flk-1/KDR mediates angiogenesis but not hypotension

OBJECTIVE

The concept of therapeutic angiogenesis with vascular endothelial growth factor (VEGF) has been validated in peripheral arterial disease. Its use in myocardial ischemia may be delayed as the result of the description in a porcine model of peripheral vasodilation after intraluminal injections of VEGF resulting in a 50% fatality rate by hypotension. We carried out this study to test whether VEGF-induced hypotension (1) is species specific, (2) is mediated by the receptor mediating angiogenesis, (3) is prevented by inhibition of nitric oxide synthase.

METHODS

In the rabbit corneal pocket assay we tested whether a previously published anti-idiotypic antibody (AIA) agonist of the VEGF receptor Flk-1/KDR could elicit angiogenesis. Various doses of recombinant VEGF or AIA were injected into anesthetized normotensive Wistar-Kyoto rats and the mean arterial blood pressure (MABP) was recorded. To test the implication of nitric oxide in VEGF-induced hypotension we treated the animals with a competitive inhibitor of nitric oxide synthase prior to the injection of VEGF.

RESULTS

Both VEGF and AIA induce angiogenesis but only intravenous injections of VEGF induced a rapid, transient and dose-dependent decrease in MABP. The ED50 was 0.5 micrograms. The interval between two VEGF injections required to lead to a decrease of MABP was 40 minutes. Nitric oxide synthesis inhibitor prevented, in a reversible fashion, the effect of VEGF.

CONCLUSION

VEGF-induced hypotension is not species specific. It is prevented by nitric oxide inhibition. VEGF-induced angiogenesis and hypotension are not mediated in vivo by the same VEGF receptor.

Extracellular cleavage of the vascular endothelial growth factor 189-amino acid form by urokinase is required for its mitogenic effect

Alternative splicing of vascular endothelial growth factor (VEGF) mRNA results in three distinct molecular forms of 121 or 165 (V165) amino acids that are released in the conditioned medium of cultured cells and one longer isoform of 189 amino acids (V189) that remains cell-associated. V189 has been expressed in wild type CHO-K1 cells and in glycosaminoglycan-deficient pgsA-745 Chinese hamster ovary (CHO) mutant cells. It could be released from CHO-K1 cell membranes by heparin or a synthetic peptide designed on the sequence encoded by exon 6 but was freely released from CHO mutant cells. In both cases, the immunoreactive V189 was mainly released as a 40-kDa cleaved form, provided that the serine protease urokinase, but not plasmin, was active. Recombinant V189 was purified from insect cells infected with a recombinant baculovirus as a nonmitogenic 50-kDa precursor that binds to the receptor Flt-1 but not to Flk-1. It could be matured by urokinase as a 38-kDa fragment able to bind to Flk-1 and to trigger cell proliferation. V165 and V189, however, could be cleaved by plasmin as 34-kDa fragments that exhibit a decreased mitogenic activity. These findings indicate that the carboxyl-terminal domain of V189 masks its binding domain to Flk-1.

Combined foscarnet -ganciclovir treatment for cytomegalovirus infections after allogeneic hemopoietic stem cell transplantation (Hsct)

Thirty two allogeneic bone marrow transplant (BMT) recipients, aged 16-55 (median 35), with CMV antigenemia (= > 5 positive cells) developing at a median interval from BMT of 49 days, were given combined treatment with foscarnet and ganciclovir for 15 days. Maintenance was given with foscarnet and ganciclovir on alternate days for an additional 2 weeks. 31/32 patients were on cyclosporin 30 on systemic antibiotics and 9 were on intravenous amphotericin Median laboratory values on day 1 and 15 of treatment were respectively creatinine 1.0-1.1 mg%; WBC 5.7-4.1 x 10(9)/l; platelets 78 72 x 10(9)/l. All patients cleared CMV-antigenemia by day +15, though 5 reactivated on and 14 off maintenance: the dose of foscarnet (but not ganciclovir) received in the first 15 days was significantly lower in patients reactivating within 30 days (p = 0.0002). Six patients died, one with i.p., one with multiorgan failure, and four with infections. Eighteen patients survive 119-1051 days post-transplant. The actuarial TRM at 1 year is 23%. This study shows that combined foscarnet-ganciclovir is one therapeutic option for allogeneic BMT recipients developing CMVAg-emia with a high number of CMVAg+ cells: treatment can be given together with cyclosporin and antibiotics with appropriate dose reductions; it produces prompt clearing of CMV infection, and may reduce transplant related mortality when compared to single agent therapy.

Study on aneuploidy and p53 mutations in astrocytomas

To determine whether a correlation exists between aneuploidy and p53 status in astrocytic tumors we analyzed 48 astrocytomas with different grades of malignancy for the presence of p53 mutations and aneuploidy of chromosomes 10 and 17 (Ch10, Ch17), known to be particularly involved with this type of tumor. We used polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) analysis on exons 5-8 of the p53 gene, and fluorescence in situ hybridization (FISH) analysis on interphase nuclei using chromosome specific pericentromeric probes, respectively. Our results showed that Ch10/Ch17 aneuploidy is a common early event in astrocytomas (90% of low grade tumors are aneuploid). p53 mutations and Ch17 aneuploidy are early events, but their incidence is not dependent on tumor grade. Loss of Ch10 is the only alteration that significantly correlates with tumor progression. No significant correlation between the presence of Ch10/Ch17 aneuploidy and p53 mutations was found. However, the coexistence of p53 mutations and aneuploidy, was observed in a subset of cases. The presence of p53 mutations appeared to be a significant predictor of a poor prognosis. In conclusion, genomic instability may or may not be associated with p53 mutations in astrocytomas, thus suggesting that other cellular determinants can also be responsible for the aneuploidy observed.

p53 expression in normal versus transformed mammalian cells

To answer the question whether the level of p53 expression also reflects the status of a cell, with reference to transformation and genome stability, we have examined, by immunocytochemistry, the presence of p53 protein in a number of cell types including human diploid cells, Chinese hamster embryonal cells at different passages and gene amplified and/or transformed Chinese hamster cell lines. Primary human fibroblasts at early passage (LEO) and an established, non transformed, Chinese hamster cell line at early passage (CHEF/18) did not show any detectable p53 expression, either nuclear or cytoplasmic. All transformed human (Raji) and Chinese hamster cell lines (CHO, V79, V79/B7) showed a nuclear expression of p53, although at different intensities. Two cell lines selected from V79/B7 for their resistance to phosphonacetyl-L-aspartate or methotrexate and previously shown to bear gene amplification, showed p53 expression. In PALA L cells p53 expression was nuclear as in other positive cell lines tested, while in MTX M cells it was cytoplasmic. CHEF/18 cells at late passage in culture showed the typical behaviour of transformed cells and p53 was detected in several cells. Moreover, when transformed CHO cells were treated with compounds known to induce reverse transformation, both the disappearance of hallmarks of transformed phenotype and p53 reduction were observed. These results indicate a strong association within the same cell type between p53 expression and transformed status.

Vasculotropin/vascular endothelial growth factor is an autocrine growth factor for human retinal pigment epithelial cells cultured in vitro

Vasculotropin (VAS), also called vascular endothelial growth factor (VEGF) or vascular permeability factor, is a secreted growth factor whose target cell specificity has been reported as restricted to vascular endothelium. Its effects are mediated by at least two distinct membrane-spanning tyrosine kinase receptors, KDR and flt-1; the expression of which also seems restricted to vascular endothelium. We describe here that cultured human retinal pigment epithelial (HRPE) cells express both KDR and flt-1 receptors, bind VAS/VEGF on two high affinity sites (apparent Kd of 9 and 210 pM corresponding to 940 and 18,800 sites per cell) and proliferate or migrate upon recombinant VAS/VEGF addition. HRPE cells also express the mRNA corresponding to the 121 and 165 amino acid forms of VAS/VEGF. HRPE cells release in their own culture medium and store in their extracellular matrix self-mitogenic and chemoattractant factors indistinguishable from 121 and 165 VAS/VEGF isoforms. The autocrine role of VAS/VEGF was confirmed by the inhibition of these bioactivities by neutralizing specific anti-VAS/VEGF antibodies.

[Optic glioma in 3 patients with Recklinghausen disease]

BACKGROUND

Patients with neurofibromatosis demonstrate a very variable clinical picture with signs that are largely age dependent. Rarely a glioma is the first presenting sign of the disease.

PATIENTS

Three patients with gliomas of the optic nerve and chiasm with neurofibromatosis 1 (NF1) were followed for 10-20 years. Clinical course and therapy are discussed.

CONCLUSION

The correct diagnosis of exophthalmos, papilledema or optic atrophy in childhood is facilitated by family history and examination of an adult member of the family, who is likely to have already developed café-au-lait spots, neurofibromas of the skin, axillary freckles and Lisch nodules as clinical signs of neurofibromatosis.

CMV prophylaxis with foscarnet in allogeneic bone marrow transplant recipients at high risk of developing CMV infections

Eleven patients underwent bone marrow transplant (BMT) from an HLA-identical sibling following single dose total body irradiation (TBI), with in vivo and ex vivo T cell depletion (TCD). In spite of CMV prophylaxis with acyclovir and high-dose i.v. Ig, 10 of 11 patients developed CMV antigenemia, at a median interval from BMT of 34 days (range 16-72 days) and five died with CMV disease. Foscarnet was then given prophylactically in 11 additional TCD patients to test whether we could (1) prevent CMV reactivation, and (2) reduce transplant-related mortality. Foscarnet was given daily from days +10 to +15 (180 mg/kg/day), then thrice weekly (90 mg/kg/day) until day +100. Five patients developed CMV antigenemia at a median interval from BMT of 42 days (range 16-65 days); one progressed to CMV pneumonitis and died. The risk of developing CMV antigenemia within day 100 is currently 91% for the historical control group and 45% for the foscarnet group (p = 0.005). At diagnosis of CMV, the median number of CMV antigen-positive cells was 6.5 (range 1-13) vs 1 (range 1-5) in acyclovir vs foscarnet patients (p = 0.02) and the median highest number of CMV antigen-positive cells was 7 (range 3-110) vs 1 (range 1-12), respectively, (p = 0.03). The actuarial 1 year transplant-related mortality (TRM) is 49% and 13% in the two groups (p = 0.08). This study suggests that foscarnet prophylaxis starting on day +10 post-BMT may be helpful in reducing the risk of CMV disease and early mortality following TCD BMT.

Early treatment of CMV infections in allogeneic bone marrow transplant recipients with foscarnet or ganciclovir

Twenty-five patients with hematologic malignancies (n = 21) or aplastic anemia (n = 4) undergoing an allogeneic BMT from an HLA-identical sibling developed cytomegalovirus (CMV) antigenemia at a mean interval from BMT of 41 days (range 16-141 days). All patients were treated at the time of antigenemia in the absence of other signs of CMV disease with ganciclovir (n = 13) or foscarnet (n = 12) if the WBC count was < 2.5 x 10(9)/l or the patient had aplastic anemia. The two groups were comparable for age, sex and disease status. There were more patients receiving T cell-depleted grafts in the foscarnet group (58% vs 15%, p = 0.003). The first course of treatment was planned to last a minimum of 10 days: foscarnet was given at 180 mg/kg/day, and ganciclovir at 10 mg/kg/day. Patients still showing pp65-positive cells continued treatment in the absence of adverse effects such as cytopenia and/or increased creatinine levels. Maintenance treatment was given for 3-4 weeks. End-points of the study were (1) clearing of CMV antigenemia, (2) tolerance and side-effects, and (3) progression to CMV disease. Both agents were effective in clearing CMV antigenemia: 14 of 25 patients were CMV antigen-negative by day 14 of treatment and all surviving patients were negative by day +50. Renal toxicity was seen mainly in the foscarnet group but caused discontinuation of the drug only in one patient. Myelotoxicity was seen in the ganciclovir group and again could be controlled in 12 of 13 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium-lithium countertransport activity as a determinant of deterioration of glomerular function in IgA nephropathy

We measured Na+/Li+ CT in 16 IgA nephropathy patients. Records were reviewed (mean observation period 5.5 years) for serial measurements of blood pressure (BP), urinary protein excretion, GFR (51Cr-EDTA) and plasma creatinine. Na+/Li+ CT correlated with the slope of the plot of GFR versus time (rs = -0.66, p = 0.005) systolic BP at diagnosis (rs = 0.62, p = 0.011) and both systolic and diastolic BP at the end of follow-up (rs = 0.69, p = 0.003, and rs = 0.56, p = 0.023). A diastolic blood pressure (DBP) > or = 95 mm Hg was associated with a faster rate of GFR decline (rate of change of GFR: -0.40 vs. -0.14 ml/min/month, p = 0.07; for DBP > or = 95 vs. < 95 mm Hg, respectively). In a multiple regression analysis with the rate of decline of GFR as dependent variable, Na+/Li+ CT emerged as a significant and independent determinant of the rate of fall of GFR (beta coefficient -1.56, SE beta 0.49, p = 0.006) and explained 52.7% of the variation in the GFR fall. Higher activities of Na+/Li+ CT are significantly associated with an increased rate of deterioration of renal function in IgA nephropathy; part of this effect could be mediated by higher blood pressure values.

[Monitoring of intravenous heparin therapy after thrombolysis. Is management by nurses possible?]

IV heparin is a very common therapy in CCUs. In Udine CCU, after the definition of common guidelines, nurses were experimentally charged to administer and monitor the heparin therapy in myocardial infarction patients. Hemorrhagic complications in thrombolyzed and heparinized patients were analysed. No differences were observed with respect to the frequence of complications between the "control" year 1992 before the experiment of autonomy and the following year 1993 (10/67 vs 16/97, OR: 1.1). It can therefore be concluded that nurses are able to administer and monitor IV heparin therapy autonomously from close medical supervision and guidance.

Fluorescence quenching at interfaces and the permeation of acrylamide and iodide across phospholipid bilayers

Studies of fluorescence quenching in membrane proteins are complicated by the fact that the barrier effect of the bilayer towards the quenchers is not known with precision. Our studies show that (a) both acrylamide and iodide can permeate the membrane at comparable rates, (b) when quenchers are added externally to a vesicle suspension, the apparent Stern-Volmer quenching constants for the same fluorophores are lower in the inner than in the outer aqueous compartments, and (c) at least some non-polar fluorophores embedded in the bilayer are quenched by iodide, but not by acrylamide.

[Lung abscess: evolution of a complication over 45 years]

143 patients with lung abscesses were hospitalised at the Department of Surgery at University Hospital Zurich from 1946 to 1990. Analysing our patients in a retrospective study we concluded as follows: 1. Lung abscesses have nearly disappeared in our patients. 2. Lung abscesses can be cured without lethality. 3. Cancers of the lung causing abscesses were not seen any more since 1960. 4. A compromised immunological system appeared as a new pathogenetical factor since the beginning of the 1980ies.

Palmitate transport through the blood-retina and blood-brain barrier of rat visual system during aging

The permeability-surface area product (PA) of [1-14C]palmitate at the blood-retina (BRB) and blood-brain barrier (BBB) was determined after short carotid perfusion in male Sprague-Dawley rats at 4, 14 and 28 months of age. For the retina, optic nerve and tract, lateral geniculate body, visual and parietal cortex, there was no significant difference among mean PAs in any age group. For superior colliculus, frontal cortex, striatum, hippocampus and olfactory bulb, a slight but significant increase of PA values was observed between young (4-month-old) and senescent (28-month-old) rats. Our results indicate that aging does not affect influx into retina and other structures of rat visual system of the palmitate, a metabolic substrate for which carrier-mediated transport across the BRB and BBB has not been demonstrated.

Gout, uric acid and purine metabolism in paediatric nephrology

Although gout and hyperuricaemia are usually thought of as conditions of indulgent male middle age, in addition to the well-known uricosuria of the newborn, there is much of importance for the paediatric nephrologist in this field. Children and infants may present chronically with stones or acutely with renal failure from crystal nephropathy, as a result of inherited deficiencies of the purine salvage enzymes hypoxanthine-guanine phosphoribosyltransferase (HPRT) and adenine phosphoribosyltransferase (APRT) or of the catabolic enzyme xanthine dehydrogenase (XDH). Genetic purine overproduction in phosphoribosylpyrophosphate synthetase superactivity, or secondary to glycogen storage disease, can also present in infancy with renal complications. Children with APRT deficiency may be difficult to distinguish from those with HPRT deficiency because the insoluble product excreted, 2,8-dihydroxyadenine (2,8-DHA), is chemically very similar to uric acid. Moreover, because of the high uric acid clearance prior to puberty, hyperuricosuria rather than hyperuricaemia may provide the only clue to purine overproduction in childhood. Hyperuricaemic renal failure may be seen also in treated childhood leukaemia and lymphoma, and iatrogenic xanthine nephropathy is a potential complication of allopurinol therapy in these conditions. The latter is also an under-recognised complication of treatment in the Lesch-Nyhan syndrome or partial HPRT deficiency. The possibility of renal complications in these three situations is enhanced by infection, the use of uricosuric antibiotics and dehydration consequent upon fever, vomiting or diarrhoea. Disorders of urate transport in the renal tubule may also present in childhood. A kindred with X-linked hereditary nephrolithiasis, renal urate wasting and renal failure has been identified, but in general, the various rare types of net tubular wasting of urate into the urine are recessive and relatively benign, being found incidentally or presenting as colic from crystalluria. However, the opposite condition of a dominantly inherited increase in net urate reabsorption is far from benign, presenting as familial renal failure, with hyperuricaemia either preceding renal dysfunction or disproportionate to it. Paediatricians need to be aware of the lower plasma urate concentrations in children compared with adults when assessing plasma urate concentrations in childhood and infancy, so that early hyperuricosuria is not missed. This is of importance because most of the conditions mentioned above can be treated successfully using carefully controlled doses of allopurinol or means to render urate more soluble in the urine. Xanthine and 2,8-DHA are extremely insoluble at any pH. Whilst 2,8-DHA formation can also be controlled by allopurinol, alkali is contraindicated. A high fluid, low purine intake is the only possible therapy for XDH deficiency.

CMV infections following allogeneic BMT: risk factors, early treatment and correlation with transplant related mortality

BACKGROUND

The impact of early detection of CMV infections in allogeneic bone marrow transplantation (BMT) and of early treatment with ganciclovir is still uncertain.

METHODS

98 patients undergoing allogeneic BMT for hematologic malignancies (n = 91) or aplastic anemia (n = 7) were monitored weekly for the expression of the lower matrix protein pp65 of cytomegalovirus (CMV) on peripheral blood cells (PB) and urine sediments (U) as detected by C10 and C11 monoclonal antibodies (Clonab, Biotest) and immunoperoxidase. Bronchoalveolar lavage (BAL) cytospin preparations were also studied in patients with clinically documented interstitial pneumonia. Patients were considered to be infected with CMV if pp65 was detected in PB (n = 15) or BAL cells (n = 6), or in the presence of serum CMV-IgM with (n = 7) or without (n = 3) pp65-positive cells in urine sediments.

RESULTS

The overall actuarial risk at 300 days of developing a CMV infection was 35%. CMV serum/status (IgG) pre-BMT of donor and/or recipient predicted the occurrence of CMV infections post-BMT: in neg/neg donor/recipient pairs (n = 17) the actuarial risk at 300 days was 0%, compared to 41% in pairs in which donor and/or recipient were CMV seropositive (n = 81) (p = 0.001). 24/31 patients were treated with ganciclovir (DHPG), and 17 survive. Mortality of patients treated early with DHPG on the basis of CMV antigenemia was 18% compared to 42% for untreated patients (p = 0.9). Pretransplant donor/recipient seropositivity accurately predicted transplant related mortality (TBM): 6% in neg/neg pairs vs 41% in all other combinations (p = 0.008).

CONCLUSIONS

The risk of developing CMV infections post-BMT can be predicted by pre-transplant serostatus, diagnosed by monitoring the expression of pp65-protein and correlates with transplant related mortality. The latter appears to be reduced by early treatment with DHPG.

New polymorphic HLA-DR epitopes recognized by three monoclonal antibodies produced against DR103 transfected L cells

Production of monoclonal antibodies directed against polymorphic epitopes of HLA class II molecules using whole human cells as immunogen has often proved ineffective, because most of the antibodies produced are directed against non-MHC human cell surface molecules. One approach to overcome this problem is the use of transfected mouse L cells expressing a single HLA class II allele as immunogen. By immunizing C3H mice with DR103-transfected L cells, we obtained 3 mAb, OHA TM901, OHA TM902, and OHA TM903, that recognize different polymorphic epitopes of the HLA-DR molecule. The molecular specificities of the 3 mAb were determined on a large panel of B-lymphoblastoid cell lines (B-LCL), peripheral blood cells and HLA class II transfectants from the XIth International Histocompatibility Workshop. Interestingly, the 3 polymorphic mAb detect new HLA-DR epitopes shared by several specificities: OHA TM901 reacts with DR1 (DR101, DR103), DR9 (DR901) and DR10 (DR1001) molecules; OHA TM902 recognizes the same molecules but also DR8 (DR801, 802, 803); OHA TM903 reacts with all DR types except DR3 (DR301, 302), DR7 (DR701, 702) and DR52. Surprisingly, OHA TM901 reacts with DR9 transfectants and B-LCL but not with DR9 peripheral blood lymphocytes. Biochemical analyses indicate that the 3 mAb immunoprecipitate HLA-DR products and react in western blots with DR alpha/beta-dimer but not with free alpha- or beta-chains. This study shows that transfected L cells are very useful tools for the production and the fine characterization of mAb recognizing polymorphic epitopes of HLA class II molecules.

Bone marrow harvest for marrow transplantation: effect of multiple small (2 ml) or large (20 ml) aspirates

The aim of this study was to evaluate the yield of nucleated cells and CFU-GM and the T cell composition in bone marrow harvested by means of multiple small (2 ml) or large (20 ml) aspirations. Eleven marrow donors were studied: each donated 1000 ml of bone marrow in two aliquots of 500 ml for an HLA identical sibling transplant. In six cases the first 500 ml were harvested by means of multiple 2 ml aspirations (A) and the second 500 ml by means of 20 ml aspirations (B). In five cases the opposite was done: 20 ml aspirates first (C) and 2 ml afterwards (D). From each 500 ml aliquot a sample was taken for enumeration of nucleated cells and CD3+ lymphocytes and for CFU-GM growth. Small volume aspirations (groups A and D) yielded more nucleated cells (p = 0.02), more CFU-GM (p = 0.03) and fewer CD3+ cells (p = 0.1) when compared with large volume aspirations (groups B and C). This study shows that marrow harvesting by means of multiple small volume aspirations minimizes the dilution with peripheral blood and results in greater numbers of cells and hemopoietic progenitors.

Familial juvenile gouty nephropathy with renal urate hypoexcretion preceding renal disease

This paper reports investigations in a young woman with renal disease and six other seemingly healthy young members of a new kindred (four male:two female) with familial juvenile gouty nephropathy (McKusick 16200). The family had previously been known to have a "familial" renal disease, but came to attention through an isolated episode of gout in the propositus when renal function was already impaired. A reduced GFR was found in three of the other six subjects. Hyperuricemia associated with a grossly reduced fractional uric acid clearance (Cur/Ccr x 100) was present in the propositus and five kindred members, three of whom were children. The finding of this abnormality in two subjects with normal GFR suggests that this apparent hallmark of the disease precedes the onset of renal damage. The results confirm the dominant nature of the disorder, and highlight the need to investigate all kindred members of patients with juvenile gout and renal failure. Early recognition is important, since allopurinol therapy in doses adjusted to the reduced renal function may ameliorate the progression of the renal lesion.

Retinoblastoma. Combined treatment of 21 cases. Critical review of the results

The authors report their experience in the treatment of 21 children affected by retinoblastoma. There were 14 bilateral and seven unilateral cases of retinoblastoma; mean age at diagnosis was 16 months in males (16 patients) and 30 months in females (five patients). They were all staged according to Howarth et al. (1980) and treatment was correlated to the various stages. The treatment protocol was determined by a group of co-workers at the University of Padova. Among the 35 affected eyes, 26 were enucleated and the others were treated without surgery. One patient died of cerebral metastases and two patients are affected by a second tumor with an unfavorable prognosis for survival. Two other patients are affected by chronic liver disease, probably due to chemotherapy. The authors confirm the importance of early diagnosis and prompt and effective treatment in children affected by retinoblastoma. They also stress that recently developed genetic techniques allow diagnosis of retinoblastoma even before the symptoms appear.