Modifications in the distribution of met-enkephalin in the cat spinal cord after administration of clonidine. An immunocytochemical study

We have studied the modifications in the distribution of methionine-enkephalin in the cat spinal cord after intravenous or intrathecal administration of clonidine by using an immunocytochemical technique. In animals not treated with the substance, a very high density of immunoreactive fibers was found in layers I and II; a high density in the dorso-lateral funiculus and in the reticular formation; a moderate density in layers III, IV and V; and a low density in layer VI. However, after intravenous or intrathecal administration of clonidine a decrease in fibers containing met-enkephalin was observed in layers I and II (high or moderate density), the dorso-lateral funiculus, and the reticular formation (moderate or low density), and in layers IV and V (low or very low density). In all cases, the decrease in the immunoreactivity was more marked when clonidine was administered intrathecally. Our results suggest that clonidine induces the release of metenkephalin in the spinal cord. They further suggest that the opioid peptide released could be involved in the control of nociceptive transmission by inhibiting the release of neurotransmitters (e.g., substance P). In summary, our study shows that clonidine could be involved in antinociceptive mechanisms in the cat spinal cord.

Engineered peptides corresponding to segments of the H3 domain of syntaxin inhibit insulin release both in intact and permeabilized mouse pancreatic beta cells

Syntaxin is one of the proteins involved in the exocytotic event through sequential binding to specific proteins, including SNAP25 and synaptobrevin. In a previous work in digitonin-permeabilized beta cells, we characterized the functional role of two segments: synA and synB of the H3 domain of syntaxin. As a continuation of these experiments in the present study we have initially outlined a zone of 17 residues as the very effective uncoupling element of the synA segment. Further functional studies have been accomplished in intact pancreatic beta cells with a specific myristoylated (myr) 13-mer peptide comprised in this active zone. These experiments showed a concentration-dependent inhibition of glucose-induced insulin release (IC50 = 4 microM) of this engineered peptide that was specific since a myristoylated random peptide with the same composition was ineffective. A second myristoylated 13-mer peptide comprised into the synB segment was shown to be even more potent promoting a selective inhibition of insulin release. These data show for the first time, that nutrient-induced secretory process can be specifically uncoupled in intact beta cells demonstrating at the same time that syntaxin plays a central role in this mechanism.

Modifications in the distribution of met-enkephalin in the pons of the cat, following the intravenous administration of clonidine: an immunocytochemical experimental study

The distribution of met-enkephalin in the cat and its modifications following the stimulation by intravenous clonidine, was studied with indirect immunocytochemical techniques. We observed a decrease in the immunoreactivity of met-enkephalin following the administration of clonidine, relative to the controls, in the following structures: locus coeruleus, nucleus cuneformis, formatio reticularis, nucleus gigantocellularis, nucleus reticularis lateralis, nucleus reticularis, nucleus reticularis parvocellularis, nucleus sensorius superior n. trigemini, nucleus raphes, substantia grisea periventricularis, nucleus eminentiae teretis, colliculus inferior, nucleus motorius n. trigemini, nucleus tracto spinalis n. trigemini, tractus spinalis n. trigemini and nucleus tracto mesencephalici n. trigemini. These experimental observations link the immunoreactivity changes to the structures that are associated with the direct action of clonidine and conclude that the pars metencephalinergicus of the efferent pontine pathway of pain is in morpho-functional relationship with the analgesia produced by clonidine; an analgesic of an endogenous opiate character.

Immune response to three doses of quadrivalent rotavirus vaccine: 1-year follow-up

Twenty-eight children who received three doses of the quadrivalent rotavirus vaccine with 4 x 10(5) plaque-forming units (p.f.u.) were followed during a year after vaccination. Serum samples were obtained and evaluated for rotavirus IgA and neutralizing antibodies against vaccine and human rotavirus strains. At the end of the study, up to 61% of the children showed an increase in circulating IgA antibody levels. Nearly all of the vaccinated children increased their neutralizing antibody titres against the vaccine strains, and 25-54% against human rotavirus serotypes. After comparing the vaccinees with a population of children naturally infected with serotype G1 in the same study area, we conclude that three doses of 4 x 10(5) p.f.u. of the quadrivalent vaccine should prepare the child against future severe rotavirus diarrhea.

[Blood levels of soluble ICAM-1 in patients with multiple sclerosis]

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. The Intercellular Adhesion Molecule plays a fundamental part in the migration of T cells to the inflammed tissues. It is known that there is an increase in the expression of endothelial cells and other cells found in lesions of the central nervous system of MS patients. ICAM-I may be detected in its soluble form in serum and it is of interest to understand its behaviour in this liquid since it is easily accessible.

MATERIAL AND METHODS

We studied the concentration of soluble ICAM-I in the serum of patients with MS: one group which had clinical attacks were studied whilst in remission; another had the chronic progressive clinical form and a third group had optic neuritis as the probable initial sign of the disorder. Within the different clinical forms, some patients received treatment with beta-interferon or azathioprine and others did not.

RESULTS AND CONCLUSIONS

We found a significant increase in the levels of soluble ICAM-I in patients with inactive, untreated MS as compared with normal persons, with no difference found between the different clinical types.

[Results of surgical treatment of non-microcytic bronchopulmonary carcinoma in III-A stage]

To analyze results and survival after surgical treatment of various stage III-a subgroups. We reviewed 748 case histories of patients with non-small cell bronchopulmonary carcinoma between January 1970 and December 1991, selecting 121 patients who underwent resection of stage III-a tumors, according to the pathologist's report. Overall survival at 3, 5 and 10 years was 26, 16 and 12%, respectively. The subgroup with better response to treatment was that of patients with T-3 tumors (peripheral), N-0, with survival of 21% at five years. If peribronchial and/or hilar (N-1) nodes were affected, survival was slightly less (16%). If mediastinal adenopathy (N-2) was present, there were no survivors after 3 years. In this same T-3 group, but with neoplastic invasion of the pericardium, mediastinal pleura or principal bronchi, survival after 3 years was nil. The survival rates of peripheral T-3 patients undergoing block resections were 27, 20 and 17% at 3, 5 and 10 years, respectively, 16% at 2 years and 0% at 5, for those with extrapleural resection. Patients with the poorest response to treatment were those with mediastinal nodes (N-2), in whom survival was 17, 12 and 8% at 3, 5 and 10 years, respectively. In the 34 patients received postoperative irradiation of the mediastinum, survival was 16% higher. The survival rates after 5 years were similar for epidermoid carcinoma (18%) and adenocarcinoma (14%). The results of surgical treatment are variable and depend on several factors: extension and extrapulmonary location of lesions, surgical technique used for T-3 tumors and histological type.

Histomorphometric changes after small bowel transplantation

AIM

Rejection results in destruction of the intestinal mucosa. This is the major cause of morbidity and morbility in human allografts. The aim of this study was to investigate histomorphometric changes in both the graft and recipient intestinal mucosa after experimental orthotopic small bowel transplantation.

EXPERIMENTAL DESIGN

Using the pig model, 21 large-white pigs underwent: laparotomy (n = 7) (control group); orthotopic small bowel transplantation without immunosuppression (n = 7); and orthotopic small bowel transplantation with cyclosporine A (n = 7).

RESULTS

1) Significant reduction of total mucosal thickness (villi plus crypt) (p < 0.05) in both the graft and recipient mucosa; 2) Attenuation of this effect by administration of cyclosporine A, which reduced the loss of mucosal thickness mainly at the expense of crypt hipertrophy.

CONCLUSIONS

These findings suggest that villi and crypt length measurements may be a reliable method for monitoring rejection after small bowel transplantation.

[Disappearance of the radiographic image of a macroprolactinoma after treatment with bromocriptine]

A young woman with amenorrhea-galactorrhea induced by a prolactin (PRL) secreting pituitary macroadenoma, was treated with bromocriptine 5 mg/day per os. Serum PRL levels were normal at 6 weeks and menstruation appeared at 8 weeks of treatment. When twenty months of treatment were completed, a tomographic study of the pituitary was unable to show any enlargement. Controversies related to macroprolactinomas treatment are discussed and it is suggested that treatment with dopamine agonists must be the elective treatment for patients with macroprolactinoma.

[Incidence and risk factors in fractures of the proximal femur due to osteoporosis]

Every year more than one million fractures of the proximal femur occur in the world, especially in older persons. Given the continuous aging experienced by populations, such fractures will become more frequent from year to year and will constitute a growing public health problem. The largest increase is expected to occur in countries of Latin America around the year 2050. Since nearly 70% of all atraumatic fractures in persons over 45 are due to osteoporosis, a case-control study was conducted in the city of Mar del Plata, Argentina, for the purpose of investigating the incidence of and the risk factors associated with proximal femur fractures due to osteoporosis. Between 1 August 1992 and 31 July 1993, a record was kept of all fractures of the proximal femur due to osteoporosis in persons over 50 years of age that visited any of the city's 30 public and private health centers. A total of 246 cases was recorded. The incidence rate per 100,000 inhabitants in the above-50 population was 259 among women and 92 among men, for a ratio of 2.8:1. The incidence was consistently higher in the older age groups, especially in persons over 75. Factors associated with a statistically significant increased risk of fracture of the proximal femur were: a history of neurologic disorders, psychotherapeutic drug use, alcohol consumption, previous fractures, cardiovascular disease, and a decreased intake of milk products. There were no observed differences between cases and controls with respect to age at menopause, weight, height, previous activity, smoking habits, or sun exposure, nor were such differences detected in terms of the percentage of women who had undergone oophorectomy.

Allelic polymorphisms in the transcriptional regulatory region of apolipoprotein E gene

In this work, we explored the existence of genetic variants within the apolipoprotein E gene transcriptional regulatory region, using a denaturing gradient gel electrophoresis screening of a region comprising nucleotides -1017 to +406. Upon a population study, three new polymorphic sites (-491, -427 and -219) and two mutations were found. Functional effects of the polymorphisms, assayed by transient transfection and electrophoretic mobility shift assays in a human hepatoma cell line, showed that polymorphisms at sites -491 and -219 of the APOE promoter produce variations in the transcriptional activity of the gene, most probably through differential binding of nuclear proteins.

[True hermaphroditism with bilateral ovotestis]

A nineteen years old woman with ambiguous external genitalia was studied. This condition had been previously identified as a newborn, but her parents refused medical attention and it was reared as a girl. At 12-years, she began spontaneous mammary development, appearing pubic and axillary hair, and clitoral enlargement. The menarche occurred at 15-years and it was followed by irregular periods. Physical examination, showed absence of hirsutism and acne, normal mammary development equivalent to grade V of Tanner. The external genitalia showed fused labio-scrotal folds with an small introitus. The urethral meatus was absent and was later located inside the introitus. There was a big phallus similar to an adult penis with a normal glans, flexed by a chordee. Hormonal determinations discarded congenital adrenal hyperplasia. The karyotype was 46,XX and testosterone levels were in adult male range. Pelvic ultrasonography disclosed a normal uterus and both gonads in confirmed by laparoscopy identifying bilateral ovotestis. Testicular tissue was removed and plastic reconstruction of female genitals was done.

A polymorphism in the regulatory region of APOE associated with risk for Alzheimer's dementia

The epsilon4 allele of the apolipoprotein E gene (APOE) has been associated with an increased risk of developing Alzheimer's disease (AD; refs 1,2). However, it is apparent that the APOEepsilon4 allele alone is neither necessary nor sufficient to cause the disease. We have recently found three new polymorphisms within the APOE transcriptional regulatory region (M.J.A. et al., manuscript submitted) and now establish an association between one of these polymorphisms (-491A/T) and dementia as observed in Alzheimer's disease, in two independent clinical populations. The results suggest that homozygosity of a common variant (-491A) is associated with increased risk for AD, and that this association is independent of APOEepsilon4 status. In vitro studies suggest that the -491A/T polymorphism may increase risk for AD by altering the level of ApoE protein expression.

Proteolysis of Alzheimer's disease beta-amyloid precursor protein by factor Xa

Amyloid beta-protein is a 4-kDa peptide which originates from proteolysis of a larger protein precursor (APP) and accumulates in senile plaques in brains of Alzheimer's disease (AD) patients. Since secreted APP inhibits factors IXa, Xa and XIa, and thrombin appears to play a role in APP secretion and proteolysis, a relationship between hemostasis system and APP metabolism seems to exist. In this work we investigate the susceptibility to proteolytic cleavage by factor Xa of a fusion construct containing full-length APP prepared in bacteria, and demonstrate that both APP695 and APP770 are substrates for this protease. Factor Xa was found to cleave APP after arginines 102, 268, 510, 573 and 601 (APP695 numeration); most of these sites appear to be common for different coagulation factors. In addition, APP incubation with factor Xa generates an array of six potentially amyloidogenic fragments. Comparative kinetic analysis of APP695 and APP770 cleavage by factor Xa suggests that Kunitz-type inhibitor-containing isoforms exert an inhibitory effect on the protease. However, this inhibition is far from complete even at a 5-fold molar excess of inhibitor. Our results raise the possibility that proteases from the coagulation cascade may contribute to APP proteolysis, and support the notion that these proteases play a role in AD pathogenesis.

Sensitivity of Leishmania spp. to glibenclamide and 4-aminopyridine: a tool for the study of drug resistance development

We have demonstrated that Leishmania spp. grown as promastigotes, are sensitive to the K+ channel inhibitors 4-aminopyridine and glibenclamide. Their host cells, the macrophages, are not affected by similar concentrations of the drugs. We have also initiated the molecular characterization of the mechanisms involved in the development of drug resistance to glibenclamide by the parasite. Therefore, we have selected experimentally and begun to characterize the Venezuelan Leishmania (Leishmania) strain, NR resistant to glibenclamide [NR(Gr)]. The analysis of genomic DNA evidenced the existence of a fragment which apparently is amplified in NR(Gr). The fragment recognized by the pgpA probe, related to the Leishmania P-glycoprotein family and which was originally isolated from L. tarentolae, showed a size polymorfism between the sensitive and the resistant strain. These results suggest that the development of resistance to glibenclamide in the strain NR(Gr) might be associated with the amplification of the ltpgpA or related gene(s).

Prognostic factors in meningococcal disease. Development of a bedside predictive model and scoring system. Barcelona Meningococcal Disease Surveillance Group

CONTEXT

Meningococcal disease is associated with significant morbidity and mortality. Development of a prognostic model based on clinical findings may be useful for identification and management of patients with meningococcal infection.

OBJECTIVES

To construct and validate a bedside model and scoring system for prognosis in meningococcal disease.

DESIGN

Prospective, population-based study.

SETTING

Twenty-four hospitals in the metropolitan area of Barcelona, Spain.

PATIENTS

A total of 907 patients with microbiologically proven meningococcal disease. Patients diagnosed with meningococcal disease from 1987 through 1990 were used to develop the prognostic model, and those diagnosed in 1991 and 1992 were used to validate it.

OUTCOME MEASURES

Clinical independent prognostic factors for mortality in meningococcal disease. The association between outcome and independent prognostic factors was determined by logistic regression analysis. A scoring system was constructed and tested using receiver operating characteristic curves.

RESULTS

Among 624 patients in the derivation set, 287 (46%) were male, the mean age was 12.4 years, and 34 patients (5.4%) died. Among 283 patients in the validation set, 124 (43.8%) were male, the mean age was 12.7 years, and 17 patients (6.0%) died. In multivariate analysis, independent predictors of death were hemorrhagic diathesis (odds ratio [OR], 101; 95% confidence interval [CI], 30-333), focal neurologic signs (OR, 25; 95% CI, 7-83), and age 60 years or older (OR, 10; 95% CI, 3-34), whereas receipt of adequate antibiotic therapy prior to admission was associated with reduced likelihood of death (OR, 0.09; 95% CI, 0.02-0.4). Hemorrhagic diathesis was scored with 2 points, presence of focal neurologic signs with 1 point, age of 60 years or older with 1 point, and preadmission antibiotic therapy was scored as -1. The clinical scores of -1, 0, 1, 2, and 3 or more points were associated with a probability of death of 0%, 2.3%, 27.3%, 73.3%, and 100%, respectively.

CONCLUSIONS

Hemorrhagic diathesis, focal neurologic signs, and age of 60 years or older were independent predictors of death in meningococcal disease, whereas receipt of adequate antibiotic therapy was associated with a more favorable prognosis. The scoring system presented is simple, is based on findings readily available at the bedside, and may be useful to help guide aggressive therapy.

The proliferating cell nuclear antigen (PCNA) gene family in Zea mays is composed of two members that have similar expression programmes

PCNA is an auxilliary protein for DNA polymerase delta whose function is to increase both polymerase activity and processivity. We have previously reported the isolation of a maize cDNA clone encoding a homologue of PCNA. Here we report the identification of a second maize PCNA cDNA clone. The nucleic acid sequence of both clones is almost identical in the coding sequences, showing 94% identity, but differs by approximately 40% in the 5' and 3' non-translated regions. Maize genomic Southern blots probed with the complete cDNAs and gene-specific probes revealed that maize contains two PCNA genes. Northern blots of RNA extracted from different plant tissues show that both genes are equally expressed in proliferating tissues.

Anti-brain spectrin immunoreactivity in Alzheimer's disease: degradation of spectrin in an animal model of cholinergic degeneration

In a previous work, we described the existence of anti-brain spectrin auto antibodies in Alzheimer's disease (AD) patients (J. Neuroimmunol. 68 (1996) 39-44). In this report, we further support our previous observations, showing that sera from 9 out of 18 AD patients, but none of 14 control subjects, immunoreacted with spectrin synthesized by PC12 cells. In addition, degradation of brain spectrin was found to be greatly enhanced in the frontal cortex of rats subjected to an animal model of cholinergic degeneration. Our data suggest that spectrin degradation and generation of anti-spectrin auto antibodies may be related to the cholinergic degeneration encountered in AD.

Apolipoprotein E forms stable complexes with recombinant Alzheimer's disease beta-amyloid precursor protein

Apolipoprotein E (apoE), a protein genetically linked to the incidence of Alzheimer's disease, forms SDS-stable complexes in vitro with beta-amyloid peptide (Abeta), the primary component of senile plaques. In the present study, we investigated whether apoE was able to bind full-length Abeta precursor protein (APP). Using a maltose-binding-protein-APP fusion protein and human very-low-density lipoprotein (VLDL), we detected an interaction of apoE with APP that was inhibited by Abeta or anti-apoE antibody. Saturation-binding experiments indicated a single binding equilibrium with an apparent 1:1 stoichiometry and a dissociation constant of 15 nM. An interaction was also observed using apoE from cerebrospinal fluid or delipidated VLDL, as well as recombinant apoE. APP.apoE complexes were SDS-stable, and their formation was not inhibited by reducing conditions; however, they were dissociated by SDS under reducing conditions. ApoE.APP complexes formed high-molecular-mass aggregates, and competition experiments suggested that amino acids 14-23 of Abeta are responsible for complex-formation. Finally, no differences were found when studying the interaction of APP with apoE3 or apoE4. Taken together, our results demonstrate that apoE may form stable complexes with the Abeta moiety of APP with characteristics similar to those of complexes formed with isolated Abeta, and suggest the intriguing possibility that apoE-APP interactions may be pathologically relevant in vivo.

[Photochemotherapy in the treatment of oral erosive lichen planus. Letter]

Photochemotherapy with 8-methoxypsoralenes and PUVA has been found to be effective in the treatment of superficial skin inflammations, such as lichen planus. However, there is little bibliography on the treatment of oral lichen planus with PUVA. A case of oral erosive lichen planus was treated with oral psoralenes (0.6 mg/kg body weight) two hours before ultraviolet exposure. Twenty sessions were held, three weekly, for a total cumulative dose of 35.9 J/cm2. After treatment concluded, clinical symptoms and erosive lesions disappeared. PUVA therapy may be useful for severe forms of erosive oral lichen planus that do not respond to conventional treatment.

Antimalaric effect of an alcoholic extract of Artemisia ludoviciana mexicana in a rodent malaria model

Chloroquine resistance of Plasmodium falciparum first and of P. vivax more recently, stimulated the search for new antimalarics. Chinese investigators have introduced new compounds obtained from extracts of Artemisia annua which possess an antimalaric active principle different from those of the drugs in use. In Mexico eight species of Artemisia have been described and among them just A. ludoviciana has been empirically used in the treatment of intermittent fever. To know whether mexican Artemisia had antimalaric activity several in vivo experiments were performed. Different type of extracts from two Artemisia species were prepared and assayed in five different doses on mice infected by Plasmodium yoelii yoelii, in a four-day test scheme. Here, only the results of the assays on ethanolic extract of A. ludoviciana are presented. The results of the in vivo experiments showed that the parasite reproduction was inhibited up to 98.6% at the fifth day, as compared with the controls; the ED50 was of 29.2 mg/kg and the SM50 of 28.7. We looked after the presence of artemisinin in the ethanolic extract, without success.

Gene transfer and therapy with adenoviral vector in rats with diethylnitrosamine-induced hepatocellular carcinoma

In rats with diethylnitrosamine (DENA)-induced hepatocellular carcinoma (HCC), we studied in vivo gene transfer efficiency using intraportal injections of recombinant adenovirus carrying the lacZ reporter gene (AdCMVlacZ) and the therapeutic efficacy of adenovirus-mediated transfer of the thymidine kinase gene of the herpes simplex virus (HSV-tk) followed by ganciclovir (GCV) administration. DENA was very effective in inducing HCC but also stimulated nontumor cell replication, as shown by proliferating cell nuclear antigen (PCNA) staining. The study of in vivo gene transfer efficiency in tumor-bearing rats showed that nontumor tissue and small tumor nodules were transduced effectively whereas a poor transduction rate was noted in large tumor nodules. Concerning therapeutic efficacy, three groups of rats with established HCC were studied: group A and B received intraportally recombinant adenovirus carrying HSV-tk (AdCMVtk) or AdCMVlacZ, respectively, and 2 days after GCV was given intraperitoneally for 9 days; group C received only saline. Of the rats from groups B and C, 100% and 93% respectively, exhibited multiple HCC tumor nodules at end of the study. In contrast, a complete regression of tumor was observed in 63% of animals from group A. This group showed significant elevation of serum transaminases and a diffuse hepatotoxic lesion in liver tissue; histological signs of regeneration were observed in surviving animals. Nine out of 19 rats from group A died during the treatment period. We conclude that (i) in the DENA model of HCC, tumoral cells can be destroyed in vivo by the HSV-tk/GCV system despite poor transduction of large tumor nodules, suggesting that toxic metabolites generated by nontumor cells may exert a bystander effect on tumor tissue; (ii) significant hepatoxicity and a high mortality rate occurred in HSV-tk/GCV-treated rats; these side effects appear to be due to the fact that in DENA-treated livers enhanced cell proliferation was present not only in tumor nodules but also in nontumor parenchyma, leading to GCV sensitization of both tissues; (iii) our results have implications concerning the efficacy and potential risks of the HSV-tk/GCV system in the treatment of human HCC.