Low energy proton irradiation effects on alveolar macrophages from young and aged rats

A prospective study was undertaken to assess the radiotoxicity of accelerated particles in pulmonary alveolar macrophages (AM). We evaluated the effects of a single dose (10-75 Gy) of an external low-energy (20 MeV) proton beam on cultured AM oxidative metabolism and phagocytic function. Macrophages are the first line of defense against invading pathogens and are known to generate superoxide anion (O2), nitric oxide (NO), and mediators of antimicrobial and antitumoral defense mechanisms. We obtained AM by bronchoalveolar lavage from young (1-2 month old) and aged (9-12 month old) male Wistar rats. Cell viability, phagocytosis, O2 and NO production in control and proton-irradiated cultured AM were evaluated The effect of proton irradiation on cell viability was dose-dependent The higher doses induced a dramatic decrease in viability in the aged population. Phagocytosis increased 1.3-1.4 fold inboth populations irrespective of the dose delivered. Generation of O2 was always higher in the aged population for all the doses assayed and showed no significant variation from the control values. In the young population a clear increase was observed with doses of 25 and 50 Gy. NO production in AM from young animals rose in a dose-dependent manner. Conversely, proton irradiation did not affect NO production in macrophages from aged animals. The results of this study demonstrate that AM isolated from young and aged rats are functionally different and show a distinct behavior when exposed to proton irradiation. These findings suggest that age may condition response and must be taken into account when accelerated particle-radiotherapy protocols are considered as a valid therapeutic option for the treatment of cancer. To the best of our knowledge, this is the first report comparing sham-irradiated and proton-irradiated young and aged AM.

Melon chlorotic leaf curl virus, a New Begomovirus Associated with Bemisia tabaci Infestations in Guatemala

In 2000, geminivirus-like symptoms were widespread in muskmelon (Cucumis melo L.) fields (70 to 80% incidence) in Zacapa Valley, Guatemala. Muskmelon fields were infested with the whitefly Bemisia tabaci (Genn.), and plants exhibited patchy foliar chlorosis, leaf curling, and reduced fruit set, which is reminiscent of symptoms caused by certain whitefly-transmitted geminiviruses. Quarantine restrictions prevented experimental transmission experiments from being carried out with the whitefly vector or biolistic inoculation. Leaves collected from six symptomatic plants were assessed for the presence of begomovirus DNA by polymerase chain reaction (PCR) with the use of degenerate primers that amplify the core region of the coat protein (CP) gene of most begomoviruses (1). PCR products of the expected size (approximately 576 bp) were obtained from all three melon samples. The core CP amplicons were cloned, and their nucleotide sequences were compared. Nucleotide sequences of core CP fragments shared 99.7% identity, suggesting the presence of a single begomovirus in all assayed symptomatic melon plants. Two additional pairs of degenerate primers were used to obtain contiguous viral fragments containing the CP gene, the common region of the A component (CR-A; approximately 2,100 bp), and a fragment containing the CR of the B component (CR-B; approximately 1,100 bp), respectively (2). At least three amplicons obtained with each primer pair were cloned and their nucleotide sequence was determined. Virus-specific PCR primers were then designed within the CP open reading frame and used to obtain fragments that overlapped with the 2,100-bp fragment to yield an apparent full-length A component of 2,662 nucleotides (accession no. AF325497). CR-A and CR-B (accession no. AF325498) sequences (161 nucleotides) shared 98.1% identity and contained an identical directly repeated, replication-associated protein (REP) binding site: GGTGT CCT GGTGT. Nucleotide sequence alignment, with CLUSTAL W, of the melon virus A-component with that of other well-studied begomoviruses revealed that its closest relatives were members of the Squash leaf curl virus (SLCV) group. The melon virus from Guatemala shared its greatest sequence identity, 83.1%, with SLCV extended (SLCV-E) (accession no. M38183), indicating that it is a new, previously unidentified begomovirus species, herein referred to as Melon chlorotic leaf curl virus (MCLCV). The next closest relatives of MCLCV were SLCV restricted (SLCV-R; 78.6%) (S. G. Lazarowitz, unpublished) Cucurbit leaf curl virus-Arizona (CuLCV-AZ; accession no. AF256199; 74.1%) (3), Cabbage leaf curl virus (CaLCV; 72.0%), Bean calico mosaic virus (BCMoV; 71.7%), and Texas pepper virus-Tamaulipas (71.4%). Additionally, the theoretical REP binding element, GGTGT, is 100% identical among MCLCV and BCMoV, CaLCV, CuLCV-AZ, SLCV-E, and SLCV-R. On the basis of shared nucleotide sequence identities with other begomoviruses described to date and the presence of B. tabaci in melon fields, it is likely that MCLCV also is whitefly-transmitted. Collectively, CP and CR sequences suggest that MCLCV is a new species of the SLCV lineage that contains other bipartite begomoviruses indigenous to Central America, Mexico, and the U.S. Sunbelt states. References: (1) S. D. Wyatt and J. K. Brown. Phytopathology 86:1288, 1996. (2) A. M. Idris and J. K Brown. Phytopathology 88:648, 1998. (3) J. K. Brown et al. Plant Dis. 84:809, 2000.

[Ovarian cysts in adolescence: epidemiologic, clinical and management assessment]

BACKGROUND

To evaluate the frequency of ovarian cyst formation in the adolescents and to report on the clinical implications of these cysts.

METHODS

A prospective analysis of data on 94 girls (aged 10-19) with diagnosed ovarian cysts was performed at the Gynecology Department of Aversa and Naples hospitals between 1995-2000. Operations were performed because of pains or ultrasound suspected features. The patients who were not operated on were kept under observation and had ultrasound tests monthly, receiving gestogen to facilitate resolution of the cyst and as treatment of menstrual disorders. The site, number, size and type of the cysts were examined.

RESULTS

The ovarian cysts were unilateral, unilocular, and simple, with the size varying between 3 cm and 5 cm in 83 cases, more than 5 cm in 8 cases and less than 3 cm in 3 cases. Among 94 patients 6 (6.4%) were initially qualified for the operation because of the strong pains or ultrasound equivocal aspect. Hormonal treatment was given in 74 cases, whereas in 14 cases only follow up sonography was performed. Cysts resolved spontaneously in 2 months on average, or in 1 month after hormonal treatment. No malignant tumors were found in the observed group.

CONCLUSIONS

Clinical observation periodically repeated ultrasound tests seems to be the most appropriate procedure employed at adolescent girls with asymptomatic ovarian cysts. Hormonal treatment shortened the duration of the cysts somewhat, even if in a not significant manner, and thus was useful mainly in the treatment of concomitant menstrual disorders.

[Borderline ovarian tumors. Retrospective analysis of 20 cases]

BACKGROUND

To evaluate the clinical features, the surgical management and outcome of 20 patients with stage-I borderline ovarian tumors.

METHODS

Twenty cases of FIGO stage-I ovarian tumors, aged from 31 to 58 years (mean 37 years) have been reviewed. All informations of clinical stage, surgical intervention and prognosis were achieved by reviewing hospital records. Minimal requirements for conservative management were adequate staging and complete information about the therapeutic options. Factors important in the choice of the treatment were, age, wish to preserve fertility, histologic type and grade, and the stage of the tumour.

RESULTS

Eleven of the 20 patients (55%) were at stage IA, 6 cases (30%) were at stage IB, 3 cases (15%) were at stage IC. Thirteen (65%) were with mucinous cystadenoma of borderline malignancy, 7 cases (35%) were of serous type. Thirteen patients underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH and BSO). Seven patients were treated with unilateral oophorectomy or unilateral salpingo-oophorectomy (USO). One patient underwent enucleation of ovarian tumor and biopsy of contralateral ovary. Any patient were treated with chemotherapy after operation. With a median follow up of two years, we observed no recurrence of carcinoma in women treated conservatively or in those treated more radically.

CONCLUSIONS

Conservative surgery remains a therapeutic option in selected patients with borderline ovarian tumors. Prolonged intensive follow-up is required for women treated conservatively for borderline malignant ovarian tumours.

Experimental study to test the potential tumor promotion effect of a tooth bleaching agent

Carbamide Peroxide is routinely employed as a whitener for tooth enamel. Oral mucosa protection is recommended to avoid inflammatory reactions. Experimental work has demonstrated its irritative effect on gastric mucosa when swallowed. The activity of certain oxidizing agents as tumoral promoters has been demonstrated and associated to their capacity to induce hyperplasia. Within this context it seemed of interest to assess the possible action of carbamide peroxide as a tumoral promoter in oral mucosa with or without a precancerous condition. Its action was tested in 2 models which are highly sensitive to chemical cancerization: a) Dorsum skin or SENCAR mice treated with carbamide peroxide daily or twice a week with or without prior initiation with dimethylbenz(a)anthracene (DMBA). Control mice were submitted to the standard carcinogenesis protocol, i.e. initiation with DMBA and promotion with 12-O-tetradecanoyl phorbol acetate (TPA). b) Hamster cheek pouch submitted to topical application of carbamide peroxide 3 times a week with or without prior initiation with DMBA, hamster cheek pouch submitted to repeated topical application of DMBA as a complete carcinogen: application twice a week in the control group and identical treatment + 1 weekly application of carbamide peroxide to evaluate its capacity to enhance the process. The effects were assessed between 1 and 14 weeks of treatment at different intervals for the different experimental protocols. The control cases exhibited hyperplasia and tumor induction in keeping with the known sequence for both carcinogenesis models. None of the cases revealed a promoter or enhancer capacity of carbamide peroxide. These results indicate the lack of risk involved in the application of carbamide peroxide even in oral mucosa with a precancerous condition due to the action of initiation agents such as tobacco and alcohol.

Succinyl-CoA:3-ketoacid CoA transferase (SCOT): cloning of the human SCOT gene, tertiary structural modeling of the human SCOT monomer, and characterization of three pathogenic mutations

The activity of succinyl-CoA:3-ketoacid CoA transferase (SCOT; locus symbol OXCT; EC 2.8.3.5) is the main determinant of the ketolytic capacity of tissues. Hereditary SCOT deficiency causes episodic ketoacidosis. Here we describe the human SCOT gene, which spans more than 100 kb and contains 17 exons, on chromosome 5p13. We report pathogenic missense mutations in three SCOT-deficient patients designated GS04, 05, and 06. GS04 is a G219E/G324E compound; GS05 is a V221M homozygote, and GS06 is a G324E homozygote. We constructed a tertiary structural model of human SCOT by homology modeling based on the known structure of Acidaminococcus fermentans glutaconate CoA transferase. The model predicts that V221 and G219 are on the dimerizing surface, whereas G324 is near the active site. SCOT activity was reduced to a comparable degree in all three patients, but in a transient expression assay in SCOT-deficient fibroblasts, cDNAs containing G219E and G324E produced no detectable activity, whereas V221M constructs yielded approximately 10% of the control peptide level and detectable specific activity. Interestingly, GS05 had the mildest clinical course reported to date and detectable levels of SCOT protein in fibroblasts.

Interleukin-6 repression is associated with a distinctive chromatin structure of the gene

Expression of the interleukin-6 (IL-6) gene is usually tightly controlled and may be induced in specific tissues only after treatment with appropriate stimuli. The molecular mechanisms responsible for IL-6 gene repression in specific tissues or cell lines remain poorly defined. In order to address this question we have studied two human breast carcinoma cell lines, MDA-MB-231, in which the IL-6 gene is expressed, and MCF-7, in which it is not. The promoter region of the IL-6 gene was analysed in both cell lines with reference to two different parameters: (i) DNase I hypersensitivity; (ii) the in vivo pattern of DNA-protein interactions. We show herein that the mechanism responsible for silencing IL-6 gene expression in MCF-7 cells most probably involves a modification of chromatin structure, as suggested by a decreased sensitivity of the IL-6 promoter to DNase I relative to the IL-6-expressing cell line MDA-MB-231. Moreover, we show that a 'closed' nucleosomal structure in MCF-7 cells does not inhibit the binding of nuclear proteins to IL-6 gene regulatory sequences in vivo. We suggest, therefore, that, in non-expressing cells, local chromatin remodelling at the proximal promoter is inhibited by negative regulators, as suggested by two specific hallmarks of nuclear factor binding that are not observed in expressing cells: an additional in vivo footprint spanning positions -135/-119 and an additional DNase I hypersensitive site far upstream, around position -1400. Furthermore, a specific factor binding in vitro to the -140/-116 region of the IL-6 promoter is found in MCF-7 cells.

Urine and plasma galactitol in patients with galactose-1-phosphate uridyltransferase deficiency galactosemia

Urinary excretion of galactitol was determined in 95 normals (N/N), 67 galactosemic (G/G), and 39 compound heterozygotes for the Duarte and galactosemia genotype (D/G). Galactitol excretion is age-dependent in both normal individuals and patients with classic galactosemia on lactose-restricted diets. In galactosemic patients who are homozygous for the Q188R mutation, urinary galactitol levels were fivefold to 10-fold higher than those of normal subjects of comparable age. All but a few patients with classic galactosemia with the Q188R mutation and another mutant G allele had urinary excretion comparable to the Q188R homozygous patients. African-American galactosemic patients with the S135L mutation of the galactose-1-phosphate uridyltransferase (GALT) gene also excreted abnormal quantities of galactitol. Most subjects with a Duarte allele and a G allele excrete normal amounts of the sugar alcohol. There is a correlation between galactitol excretion and red blood cell (RBC) galactose-1-phosphate (gal-1-P). Plasma galactitol was also elevated in galactosemic patients (3.4 to 23.2 micromol/L; undetectable in normal individuals). In contrast to the decrease in urinary galactitol with age, plasma levels remain in a narrow concentration range with no significant difference with age. Urine and plasma galactitol distinguish galactosemic patients from normals. In addition, urinary galactitol excretion may be an important parameter for the assessment of steady-state galactose metabolism in galactosemia.

Mitochondrial DNA variation among Anopheles albimanus populations

Barriers to gene flow between Pacific and Atlantic coast populations of Anopheles albimanus were reported in an earlier study of variation in the intergenic spacer of the nuclear ribosomal DNA. We examined the distribution of mitochondrial DNA haplotypes among A. albimanus populations to test for gene flow barriers with an independent genetic marker. A region of the NADH dehydrogenase subunit 5 gene was amplified by the polymerase chain reaction (PCR) in 1,105 mosquitoes collected from 16 locations in Guatemala and in single collections from Mexico, Honduras, Nicaragua, Costa Rica, Panama, Colombia, and Venezuela. The PCR products were tested for variation using single strand conformation polymorphism analysis and 45 haplotypes were detected. Haplotype frequencies did not vary between coasts in Guatemala. Populations within approximately 200 km of one another were panmictic. However, at distances > 200 km, FST and geographic distances were correlated suggesting that populations are isolated by distance.

Cell-specific differences in the regulation of IL-6 expression by PMA

We have studied the regulation of IL-6 expression in human blood monocytes and lymphocytes. LPS and IFN-gamma induced IL-6 gene expression with a similar qualitative profile in both cell types. Treatment of monocytes and lymphocytes with PMA resulted, instead, in different effects: monocytes accumulated IL-6 and its message, while lymphocytes were inhibited either in the absence or the presence of LPS and IFN-gamma. These results suggest that the signal transduction pathways triggered by LPS and IFN-gamma are similar in both cell types, while PMA may activate a tissue-specific pathway which leads to opposite responses.

Interaction of the nuclear protein CBF1 with the kappaB site of the IL-6 gene promoter

The nuclear protein CBF1 has been shown to function as an intermediate to target transcription factors,such as the activated Notch receptor,to specific DNA sites. In this paper,we show that CBF1 from cell lines of different origin is able to bind to the[kappa]B site of the IL-6 promoter. By transfection analyses performed in HeLa cells,we demonstrate that overexpressed CBF1 acts as a negative regulator of IL-6 gene transcription and is unable to elicit Notch-dependent activation of this gene. Analyses of protein-DNA interactions indicate that the topology of the complex formed by CBF1 and the target DNA is subtly affected by sequencessurrounding the recognition site. Furthermore,we show that CBF1 induces DNA bending. This finding suggests that CBF1 may influence IL-6 gene transcription by determining a specific conformation of the promoter region.

Repression of the IL-6 gene is associated with hypermethylation

The expression of the IL-6 gene is usually tightly controlled and may be induced in specific tissues after treatment with appropriate stimuli. Although much is known about the inducible expression of the IL-6 gene, the molecular mechanisms responsible for its repression in specific tissues or cell types remain poorly defined. To address this question we have studied two human breast carcinoma cell lines, MDA-MB-231, in which the IL-6 gene is expressed, and, MCF-7, in which the IL-6 message is undetectable by Northern blot assay even in the presence of inducers. The expression of the IL-6 message was estimated after treatment with 5-aza-2'deoxycytidine and the methylation state of the IL-6 gene was analyzed. We show herein that treatment of MCF-7 cells with an agent which reduces DNA methylation correlates with IL-6 gene hypomethylation and increases the level of its expression.

The differential pattern of tissue-specific expression of ruminant pancreatic type ribonucleases may help to understand the evolutionary history of their genes

Molecular evolutionary analyses of mammalian ribonucleases have shown that gene duplication events giving three paralogous genes occurred in ruminant ancestors. The enzymes of the bovine species encoded by these genes, isolated from pancreas, brain and seminal vesicles, present similar enzymological properties but distinct structural features. In other ruminant species, genomic sequences orthologous to the bovine genes of pancreas and brain ribonucleases encode active enzymes. In mammalian species other than ruminant artiodactyls, only one gene encoding ribonuclease of the pancreatic type is generally present. In this work, we describe a differential pattern of transcriptional expression of the pancreas and brain ribonuclease genes in the ox species and report transcription of the human ribonuclease gene in brain as well as in pancreas and in mammary gland. We also report the molecular cloning of the gene encoding the bovine seminal ribonuclease in which the structural organization already described for the two paralogous genes is conserved. The seminal RNAase is exclusively expressed in seminal vesicles of Bos taurus, whereas in other ruminant species, the orthologous sequence is a pseudogene. Previous studies from a number of research groups demonstrated that, unlike other mammalian ribonucleases, the seminal enzyme is a covalent dimer, and its unique quaternary structure correlates with special biological activities. The major determinant of dimer formation, i.e. the presence of two adjacent cysteine residues, is absent in the pseudogenes. We advance the hypothesis that the differentiation of distinct expression patterns could represent an important evolutionary determinant for the genes encoding pancreas and brain ribonucleases in ruminants, whereas the differentiation of a quaternary structure endowed with new biological functions could be the main determinant for the evolutionary success of the seminal gene in the bovine species.

Elevation of erythrocyte redox potential linked to galactonate biosynthesis: elimination by Tolrestat

Alternate pathways of galactose metabolism were explored in erythrocytes from normal subjects and patients with galactose-1-phosphate uridylyltransferase (GALT) deficiency incubated with galactose. Micromolar quantities of galactonate accumulated in both normal and mutant cells linearly with time up to 5 hours and with concentrations of galactose up to 25 mmol/L. Galactitol also was found at levels less than one third of the galactonate level, while galactose-1-phosphate concentrations comparable to those of galactonate were found in galactosemic cells. Concomitant with the formation of these galactose metabolites, the erythrocyte redox potential based on measurement of lactate and pyruvate increased fourfold in both cell types. This was due to a 60% to 72% decrease in pyruvate and a 24% to 26% increase in lactate. The oxidation of galactose to galactonate, which is known to generate NADH, is the most likely explanation for the increase in the redox state. The aldose reductase inhibitor (ARI), Tolrestat (Wyeth Ayerst Research, Princeton, NJ), at 70 micromol/L inhibited the formation of both galactonate and galactitol in both cell types without affecting galactose-1-phosphate, and eliminated the increase in the redox potential as indicated by restoration of pyruvate and lactate levels to the levels obtained before exposure of the cells to galactose. A functioning galactonate pathway is a route of galactose disposal in patients with GALT deficiency, but by altering the cellular redox potential, it may also contribute to galactose toxicity.

Human infection with Trypanosoma cruzi induces parasite antigen-specific cytotoxic T lymphocyte responses

Experimental models of Chagas' disease, an infection caused by the intracellular protozoan Trypanosoma cruzi, have demonstrated the crucial immunoprotective role played by CD8(+) T lymphocytes. These cells dominate inflammatory foci in parasitized tissues and their elimination from mice leads to uncontrolled parasite replication and subsequent death of the infected host. A trypomastigote surface antigen, TSA-1, and two amastigote surface molecules, ASP-1 and ASP-2, were recently identified as targets of CD8(+) cytotoxic T lymphocytes (CTL) in T. cruzi-infected mice. Until now, however, there was no evidence for the development of parasite-specific CTL in T. cruzi-infected humans. In this study, human CTL specific for TSA-1-, ASP-1-, and ASP-2-derived peptides were detected in the peripheral blood mononuclear cells from 21 of 24 HLA-A2(+) T. cruzi-infected patients. CTL recognition was antigen specific, A2-restricted, and CD8(+) T cell-dependent. Demonstration of human CTL against T. cruzi and against target molecules identified using the murine model provides important information for the optimal design and evaluation of vaccines to prevent or ameliorate Chagas' disease.

Lithostathine messenger RNA expression in different types of chronic pancreatitis

Lithostathine may play a physiological role in preventing the precipitation of excess calcium in the pancreatic juice. The hypothesis has been advanced that in chronic calcifying pancreatitis the abnormal biosynthesis of lithostathine might be the original defect to which genetic proneness to the disease may be ascribed. The aim of the present work was to study lithostathine messenger RNA expression in the pancreas of patients with different types of pancreatitis. Lithostathine and chymotrypsinogen mRNA were determined in surgical specimens obtained from the pancreases of the following subjects: (a) 13 patients with chronic alcoholic pancreatitis (84.6% calcified); (b) 4 patients with chronic hereditary pancreatitis (all calcified); (c) 6 patients with chronic obstructive pancreatitis (4 calcified); and (d) 27 subjects suffering from pancreatic cancer. Significantly lower concentrations of both mRNAs were found in the pancreases of chronic pancreatitis patients than in non-cancerous tissue from pancreatic cancer subjects. However, about 70% of the pancreatic cancer subjects showed lithostathine and chymotrypsinogen mRNA levels comparable to those of chronic pancreatitis patients. These results indicate that the decrease in the level of mRNA is not specific to lithostathine and it is unrelated to the presence of pancreatic stones.

Multicenter trial on mother-to-infant transmission of GBV-C virus. The Lombardy Study Group on Vertical/Perinatal Hepatitis Viruses Transmission

Evidence indicates that the GBV-C or hepatitis G virus can cause persistent infection in humans, but little is known on the importance of vertical transmission. To assess the risk of mother-to-infant transmission and the clinical outcome of infected babies, we investigated 175 anti-HCV positive mothers and followed-up their children for 3-33 months. GBV-C RNA was detected by RT-PCR and anti-E2 antibody was assayed by EIA. Thirty-four (19.4%) women were GBV-C RNA positive and transmission occurred to 21 (61.8%) babies; 20 (95.2%) acquired GBV-C alone, and one (4.8%) GBV-C and HCV. Maternal factors such as intravenous drug use, HIV coinfection, HCV-RNA positivity, and type of feeding were not correlated with GBV-C transmission. GBV-C RNA remained persistently positive in all infected babies but one baby who seroconverted to anti-E2. Seven (35%) babies with GBV-C alone developed marginally elevated ALT; the baby with HCV and GBV-C co-infection had the highest ALT peak value (664 IU/l). Seven of the 141 (5%) babies born to the GBV-C RNA negative mothers acquired HCV and six (85.7%) had abnormal ALT. The mean ALT peak value was significantly higher (P < 0.05) for babies with HCV than for those with GBV-C. None of the children with GBV-C or with HCV became icteric. GBV-C is frequently present in anti-HCV positive women. The infection is transmitted efficiently from mother to baby and rate of transmission is much higher than that for HCV. GBV-C can cause persistent infection in babies but usually without clear evidence of liver disease.

Multicenter trial on mother-to-infant transmission of GBV-C virus. The Lombardy Study Group on Vertical/Perinatal Hepatitis Viruses Transmission

Evidence indicates that the GBV-C or hepatitis G virus can cause persistent infection in humans, but little is known on the importance of vertical transmission. To assess the risk of mother-to-infant transmission and the clinical outcome of infected babies, we investigated 175 anti-HCV positive mothers and followed-up their children for 3-33 months. GBV-C RNA was detected by RT-PCR and anti-E2 antibody was assayed by EIA. Thirty-four (19.4%) women were GBV-C RNA positive and transmission occurred to 21 (61.8%) babies; 20 (95.2%) acquired GBV-C alone, and one (4.8%) GBV-C and HCV. Maternal factors such as intravenous drug use, HIV coinfection, HCV-RNA positivity, and type of feeding were not correlated with GBV-C transmission. GBV-C RNA remained persistently positive in all infected babies but one baby who seroconverted to anti-E2. Seven (35%) babies with GBV-C alone developed marginally elevated ALT; the baby with HCV and GBV-C co-infection had the highest ALT peak value (664 IU/l). Seven of the 141 (5%) babies born to the GBV-C RNA negative mothers acquired HCV and six (85.7%) had abnormal ALT. The mean ALT peak value was significantly higher (P < 0.05) for babies with HCV than for those with GBV-C. None of the children with GBV-C or with HCV became icteric. GBV-C is frequently present in anti-HCV positive women. The infection is transmitted efficiently from mother to baby and rate of transmission is much higher than that for HCV. GBV-C can cause persistent infection in babies but usually without clear evidence of liver disease.

Urinary galactonate in patients with galactosemia: quantitation by nuclear magnetic resonance spectroscopy

Although numerous reports have appeared showing high levels of galactitol in the urine of patients with galactose-1-phosphate uridylyltransferase deficiency, little attention has been paid to measurement of urinary galactonate. Herein we explored the use of 1H and 13C nuclear magnetic resonance, which required only the concentration of urine without derivatization, to detect and quantitate urinary galactonate. We report that transferase deficient infants, as well as adults on galactose restricted diets excrete significant amounts of galactonate, whereas none is detected in the urine of normal subjects. Galactose-toxic infants were found to excrete large amounts of galactonate, which decreased when the lactose-free diet was instituted. We also found that normal individuals subjected to an oral galactose load also excrete high levels of galactonate for at least 4 h after galactose ingestion. Our data provide evidence that the first reaction in the oxidative pathway of galactose metabolism described in rat liver in 1966 is activated in patients with a variety of galactose-1-phosphate uridylyltransferase gene mutations even while on a lactose-restricted diet. In both patients and normal individuals, flux through the alternate galactonate pathway appears to be related to the body galactose burden.

Molecular mechanisms regulating induction of interleukin-6 gene transcription by interferon-gamma

The multifunctional cytokine interleukin-6 (IL-6) plays a central role in host defence mechanisms and hematopoiesis. Furthermore, dysregulation of IL-6 gene expression is associated with the pathogenesis of various immunologically related diseases such as myeloma, systemic lupus erythematosus, rheumatoid arthritis, psoriasis and Kaposi's sarcoma. The regulation of IL-6 gene expression occurs mainly at transcriptional level, although mechanisms of post-transcriptional regulation have also been described. In the present study we demonstrate that in HeLa cells, induction of IL-6 by interferon-gamma (IFN-gamma) is transcriptionally controlled, as shown by run on assays and analysis of the IL-6 mRNA stability. Gel-retardation experiments using antibodies specific for factors of the IRF family identified four protein-DNA complexes, which bind to the interferon regulatory factor (IRF) binding site at position -267 to -254, in nuclear extracts from IFN-gamma treated cells. Furthermore, transient transfection analyses of the 5'-flanking region of IL-6 gene linked to the chloramphenicol acetyltransferase (CAT) reporter gene demonstrated that the -267 to -254 IRF site is necessary for IL-6 induction by IFN-gamma. However, transfection experiments in which IRF-1 and I kappa B alpha were overexpressed show that full-scale transcriptional activation of the IL-6 promoter directing CAT expression requires the co-operation between IRF-1 and NF-kappa B at a low constitutive level.

Dissection of pathways implicated in integrin-mediated actin cytoskeleton assembly. Involvement of protein kinase C, Rho GTPase, and tyrosine phosphorylation

A panel of antibodies to the alphaIIbbeta3 integrin was used to promote adhesion of Chinese hamster ovary cells transfected with the alphaIIbbeta3 fibrinogen receptor. While some alphaIIbbeta3 antibodies were not able to induce p125 focal adhesion kinase (p125FAK) tyrosine phosphorylation, all the antibodies equally support cell adhesion but not spreading and assembly of actin stress fibers. Absence of stress fibers was also obtained by plating on antibodies directed to the hamster beta1 integrin. In contrast, cells plated on matrix proteins spread organizing actin stress fibers. Treatment with phorbol esters phorbol 12-myristate 13-acetate (PMA) induced cells to spread on antibodies-coated dishes but not to organize actin in stress fibers. The combination of PMA and cytotoxic necrotizing factor 1 (CNF1), a specific Rho activator, induced cell spreading and organization of stress fibers. PMA or the combination of PMA and CNF1 also increases tyrosine phosphorylation of p125FAK in response to antibodies that were otherwise unable to trigger this response. These data show that: 1) matrix proteins and antibodies differ in their ability to induce integrin-dependent actin cytoskeleton organization (while matrix induced stress fibers formation, antibodies did not); 2) p125FAK tyrosine phosphorylation is insufficient per se to trigger actin stress fibers formation since antibodies that activate p125FAK tyrosine phosphorylation did not lead to actin stress fibers assembly; and 3) the inability of anti-integrin antibodies to trigger stress fibers organization is overcome by concomitant activation of the protein kinase C (PKC) and Rho pathways; PKC activation leads to cell spreading and Rho activation is required to organize actin stress fibers.

Atypical association of H1 and H2 histamine receptors with signal transduction pathways during multistage mouse skin carcinogenesis

OBJECTIVE

In the present work we studied the association of histamine receptors with second messengers during multistage carcinogenesis in Sencar mice skin.

METHODS

96 Sencar female mouse, divided into six groups were used. Tumors appeared only in the 7, 12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted group. Control groups received only TPA, or acetone or no treatment at all. Periodically during the promotion period, cAMP and inositol phosphate production were measured after stimulation with H1 or H2 agonists in samples from all groups.

RESULTS

In non-treated skin, H1 receptors were coupled to phosphatidylinositol hydrolysis and H2 receptors mediated cAMP production. Conversely, in tumors H2 receptors were associated with phosphatidylinositol hydrolysis and H1 mediated a rise in cAMP levels. The skin among tumors and the skin from all control groups maintained the same coupling as non-treated skin. An increase in mast cell number, with a homogeneous subepithelial distribution and marked phenotypic changes, was also observed in promoted skin.

CONCLUSIONS

These findings indicate an atypical association of histamine receptors with second messengers that could be a critical feature for the postulated action of histamine in tumor growth.

Krabbe's disease presenting as a peripheral neuropathy

A 13-year-old female initially presented with scoliosis and pes cavus. Initial examination revealed distal lower extremity weakness and sensory loss, as well as greater auricular nerve hypertrophy. There was a Babinski sign on the right. Nerve conduction velocities were consistent with a demyelinating neuropathy. Four years after initial presentation she developed lower extremity spasticity and bilateral Babinski signs. Magnetic resonance imaging of the brain showed diffuse white matter disease. Laboratory evaluation revealed an abnormally low galactocerebroside beta-galactosidase level. Nerve biopsy demonstrated inclusions consisting of globoid clusters and evidence of demyelination. DNA analysis was used to identify mutations consistent with Krabbe's disease. Patients presenting with an atypical peripheral neuropathy should be evaluated for Krabbe's disease.