Biomedical subjects

M Lucas

Publications and source records attributed to M Lucas.

At least 91 records · Page 5Linked to original sources

PubMed1998

Adenoidal and tonsillar lymphocyte subsets in AIDS children.

Tonsils and adenoids are secondary lymphoid organs exposed to the environment. The most important classifications of AIDS include the lymphocyte subsets of peripheral blood. We have studied the lymphocyte subsets in peripheral blood and secondary lymphoid organs in a control group of children suffering adenotonsillar pathology and in five children with AIDS and the same adenotonsillar pathology. The antigen surface markers were determined by flow cytometry in lymphocytes isolated from peripheral blood, and from tonsils and adenoids after tonsillectomy and adenoidectomy, in the control group and in children diagnosed with AIDS. The most important findings in tonsils and adenoids were a decrease of the total T lymphocytes, helper T lymphocytes and CD4/CD8 ratio; an increase of cytotoxic T lymphocytes and B lymphocytes, as well as a 200% increase in monocytes of AIDS-affected children. These observations show the value of analyzing the lymphocyte subsets of the tonsils and adenoids of AIDS-affected children, and establishing an earlier relation to clinical symptoms.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Attempted vaginal birth after cesarean section: a multicenter comparison of outpatient prostaglandin E(2) gel with expectant management.

Objective: To compare the clinical effectiveness and safety of outpatient administration of an intracervical prostaglandin (PG) E(2) gel with expectant management for women with an unfavorable cervix who wish to attempt a vaginal birth after cesarean section.Study Design: This outpatient study was a randomized, multicenter investigation involving pregnant women at term with one previous low transverse cesarean section. Each had an unfavorable cervix (Bishop score </=4) and was a candidate for vaginal delivery. Those randomly assigned to receive the gel, rather than expectant management, were given a 0.5 mg dose of PGE(2) (Prepidil) intracervically at 39 weeks gestation. This cervical ripening treatment was repeated at weekly office visits for up to 3 doses.Results: Of the 294 cases, 143 received the gel while 151 underwent expectant management. No differences between the two groups were found for maternal demographics, race, parity, or predose Bishop score. The rates of repeat cesarean section did not differ (P =.68) with use of the gel (61, 42%) or with expectant therapy (48, 45%). The onset of active labor, the duration of labor among those delivering vaginally, and the 1-minute and 5-minute Apgar scores were not different between the two groups. No uterine rupture was apparent, and adverse effects during labor were as likely to occur in the two groups.Conclusions: Although its safety was confirmed for outpatient use and for persons with a prior cesarean delivery, intracervical prostaglandin E(2) gel did not improve the chance of a vaginal birth after a cesarean delivery.

Journal Article↗

PubMed1998

[Pre- and postoperative quality of life of patients with ulcerative colitis and familial adenomatous polyposis with ileoanal pouch operation].

After ileal pouch-anal anastomosis in patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP), in addition to postoperative morbidity and functional outcome quality of life is a relevant factor for assessment of the operation's success. Between 1982 and 1997 restorative proctocolectomy was performed in 602 patients (UC: n = 424; FAP: n = 178) at the Department of Surgery, University of Heidelberg. The assessment of pre- and postoperative quality of life was done through a prospective study (before restorative proctocolectomy, before and 1 year after closure of ileostomy). This study (UC: n = 27; FAP: n = 7) revealed a poor preoperative quality of life in patients with ulcerative colitis. Proctocolectomy is the decisive factor for the improvement of quality of life in the surgical treatment in UC. Quality of life could not be further significantly improved by ileostomy closure. Before proctocolectomy, FAP patients showed a quality of life, activity and function similar to that of healthy controls. In FAP patients proctocolectomy led to a significant loss of quality of life. This loss could only partly be regained by ileostomy closure. Quality of life and activity comparable to that of healthy controls can be achieved in UC patients by restorative proctocolectomy.

Activities of Daily Living↗

PubMed1998

The production of free oxygen radicals and nitric oxide in the rat cochlea.

Rat cochleas were analysed for free oxygen radicals (FOR) and nitric oxide (NO) production by the chemiluminescent oxidation of luminol. 4Beta-phorbol-12beta-myristate-13alpha-acetate (PMA), a well-known agonist of protein kinase C, induced the release of FOR after a time lag close to 30 s and reverted to basal values in approximately 10 min. Sphingosine inhibited by nearly 50% the response to PMA, whereas staurosporine caused an inhibition of 100%. The incubation of rat cochleas with 0.5 mM arginine potentiated the chemiluminescent reaction induced by PMA causing an additional oxidation of luminol that was inhibited by the NO synthase inhibitor N-methyl-arginine (NMA). Our results show for the first time the presence in the cochlea of cell populations producing FOR and NO and the real time production following cell activation. This procedure may help to explain the mechanisms involved in ototoxicity, as in the case of streptomycin and gentamicin that enhanced PMA-dependent production of FOR and NO.

Animals↗

PubMed1998

Interferon beta-1b inhibits reactive oxygen species production in peripheral blood monocytes of patients with relapsing-remitting multiple sclerosis.

We studied the rate of reactive oxygen species (ROS) production by monocytes 'ex vivo' in a cohort of healthy individuals, in a group of MS patients undergoing treatment with interferon beta-1b and another group of MS patients who refused treatment with interferon beta-1b. The rate of ROS production in healthy individuals was slightly lower than in non-treated MS patients. The lower rate of ROS production was obtained in monocytes of MS patients treated with interferon beta-1b. These results indicate that the treatment of relapsing-remitting MS patients with interferon beta-1b rendered the NADPH oxidase of the monocytes less sensitive to trigger reactive oxygen species (ROS).

Enzyme Activation↗

PubMed1998

Endogenous apoE expression modulates HDL3 binding to macrophages.

We have previously shown that expression of a human apoE cDNA in J774 macrophages enhances cholesterol efflux to HDL3. We have also shown that endogenous apoE expression produces a cell surface pool of apoE associated with proteoglycans. In this series of experiments, we first demonstrate the presence of a cell surface proteoglycan-associated apoE pool in human monocyte-derived macrophages. We then examine the hypothesis that endogenous expression of apoE modulates HDL3 binding to macrophages, thereby, accounting for enhanced cholesterol efflux to HDL3, specifically examining a role for the cell surface pool. Enhanced binding of apoE-free human HDL3 to apoE-expressing macrophages, compared to non-expressing macrophages, was observed at 37 degrees C and 4 degrees C. The enhanced binding was not due to apoE secreted into the medium, as determined by experiments utilizing conditioned medium from apoE-secreting cells. Removal of the cell surface pool of apoE, however, substantially reduced the incremental HDL3 binding produced by apoE expression. Cellular cholesterol mass measurements demonstrated that experimental conditions that reduced HDL3 binding to apoE-expressing macrophages, did not substantially reduce cholesterol efflux to HDL3. In summary, our results document a clear role for cell surface pool of apoE in modulating HDL3 interaction with macrophages. The enhanced binding, however, does not appear to be a major mechanism contributing to the increased cholesterol efflux to HDL3, which results from endogenous macrophage expression of apoE.

Apolipoproteins E↗

PubMed1998

Management of postmenopausal osteoporosis for primary care.

OBJECTIVE: The shift in health care delivery from a subspecialty to primary care system has transferred the responsibility of preventing osteoporotic fractures from specialists in metabolic bone disease to the web of physicians--family practitioners, general internists, pediatricians, and gynecologists--who provide the bulk of primary care. The challenge for this group of physicians is to decrease the rising prevalence of osteoporotic hip and vertebral fractures while operating within the cost parameters. It is the goal of this brief summary to provide primary practitioners with focused guidelines for the management of postmenopausal osteoporosis based on new and exciting developments. Prevention and treatment will change rapidly over the next decade and these advances will require changes in these recommendations. DESIGN: We identified patients at risk for osteoporosis and provided indications for bone mass measurement, criteria for diagnosis of osteoporosis, therapeutic interventions, and biochemical markers of the disease. RESULTS: Prevention and treatment are discussed, including hormone replacement therapy and use of calcitonin, sodium fluoride, bisphosphonates, and serum estrogen receptor modulators. CONCLUSIONS: Postmenopausal osteoporosis should no longer be an accepted process of aging. It is both preventable and treatable. Primary care physicians must proactively prevent and treat osteoporosis in their daily practice, and combination therapies are suggested.

Absorptiometry, Photon↗

PubMed1998

[Familial cerebral cavernomatosis associated with cutaneous angiomas].

UNLABELLED: OBJECTIVE, PATIENTS AND METHOD: We present a genealogical study of a person with familial cerebral cavernomatosis (CCF) discovered following study of a man who presented with status epilepticus at the age of 35 years. This had also affected another three members of the family consisting of a total of 43 persons, studied over six generations. RESULTS: In the family members studied we did not find cavernomas at other sites but there were dermatological lesions whose relation to cerebral cavernomas (CC) is discussed. CCs are the second commonest type of cerebral vascular malformations. Their major clinical features are epilepsy and cerebral haemorrhage. There are two forms of CC: a sporadic form with single lesions and a familial form with multiple lesions. Although the condition has been recognized since 1854, very little is known about it. Recently a gene causing the familial form has been found on chromasome 7. CONCLUSIONS: We discuss the clinical findings in this family with relation to descriptions in the literature. We emphasize the importance of MR in diagnosis of the condition and for detection of asumptomatic carriers. We consider a possible relationship between these findings and genes which have been mapped, and in view of recent genetic data, the hypothesis of a possible Spanish ancestor with the condition.

Adolescent↗

PubMed1997

Effectiveness of periodontal treatments on cyclosporine-induced gingival overgrowth in transplant patients.

OBJECTIVE: Evaluation of the effectiveness of periodontal treatments on cyclosporine-induced gingival overgrowth. DESIGN: Longitudinal study between months 6 and 12 after transplant, in 80 cyclosporine-treated heart, liver and kidney transplant patients. SETTING: Madrid Puerta de Hierro Hospital. SUBJECTS AND METHODS: The 37 patients who had developed overgrowth in the sixth month were randomly split into three study groups. The remaining 43 were split into two additional groups. INTERVENTIONS: The first group underwent professional cleaning; the second underwent, additionally, scaling and root planing, and the third group received no treatment. The fourth and the fifth groups received no treatment and professional cleaning, respectively. MAIN OUTCOME MEASURES: O'Leary plaque index, Lenox and Kopczyk gingival index, and average gingival overgrowth. RESULTS: A significant (P = 0.008) increase in overgrowth was found in the third group that did not undergo treatment. Significantly (P = 0.002) less was found in the first and second groups. Highly significant (P = 0.001) reductions in the plaque and gingivitis indices were also found in these two groups. The fifth group showed a highly significant (P = 0.0001) decrease in the plaque and gingivitis indices. CONCLUSIONS: Professional cleaning is effective in reducing both gingivitis and cyclosporine-induced gingival overgrowth; the combination with scaling and root planing reinforces its effectiveness.

Adult↗

PubMed1997

Lipoprotein lipase reduces secretion of apolipoprotein E from macrophages.

Macrophages are a significant source of lipoprotein lipase (LPL) and apolipoprotein E (apo E) in the developing arterial wall lesion, and each of these proteins can importantly modulate lipid and lipoprotein metabolism by arterial wall cells. LPL and apo E share a number of cell surface binding sites, including proteoglycans, and we have previously shown that proteoglycans are important for modulating net secretion of apoprotein E from macrophages. We therefore evaluated a potential role for LPL in modulating net secretion of macrophage-derived apo E. In pulse-chase experiments, addition of LPL during the chase period produced a decrease in secretion of apoprotein E from human monocyte-derived macrophages, from the human monocytic THP1 cell line, and from J774 cells transfected to constitutively express a human apo E cDNA. LPL similarly reduced apo E secretion when it was prebound to the macrophage cell surface at 4 degrees C. A native LPL particle was required to modulate apo E secretion; addition of monomers and aggregates did not produce the same effect. Depletion of cell surface proteoglycans by a 72-h incubation in 4-methylumbelliferyl-beta-D-xyloside did not attenuate the ability of LPL to reduce apo E secretion. However, addition of receptor-associated protein attenuated the effect of LPL on apo E secretion. Although LPL could mediate removal of exogenously added apo E from the culture medium, detailed pulse-chase analysis suggested that it primarily prevented release of newly synthesized apo E from the cell layer. Cholesterol loading of cells or antibodies to the low density lipoprotein receptor attenuated LPL effects on apo E secretion. We postulate that LPL sequesters endogenously synthesized apo E at the cell surface by a low density lipoprotein receptor-dependent mechanism. Such post-translational regulation of macrophage apo E secretion by LPL could significantly influence apo E accumulation in arterial vessel wall lesions.

Animals↗

PubMed1997

Biochemical characterization of the mouse muscle-specific enolase: developmental changes in electrophoretic variants and selective binding to other proteins.

The glycolytic enzyme enolase (EC 4.2.1.11) is active as dimers formed from three subunits encoded by different genes. The embryonic alphaalpha isoform remains distributed in many adult cell types, whereas a transition towards betabeta and gammagamma isoforms occurs in striated muscle cells and neurons respectively. It is not understood why enolase exhibits tissue-specific isoforms with very close functional properties. We approached this problem by the purification of native betabeta-enolase from mouse hindlimb muscles and by raising specific antibodies of high titre against this protein. These reagents have been useful in revealing a heterogeneity of the beta-enolase subunit that changes with in vivo and in vitro maturation. A basic carboxypeptidase appears to be involved in generating an acidic beta-enolase variant, and may regulate plasminogen binding by this subunit. We show for the first time that pure betabeta-enolase binds with high affinity the adjacent enzymes in the glycolytic pathway (pyruvate kinase and phosphoglycerate mutase), favouring the hypothesis that these three enzymes form a functional glycolytic segment. betabeta-Enolase binds with high affinity sarcomeric troponin but not actin and tropomyosin. Some of these binding properties are shared by the alphaalpha-isoenolase, which is also expressed in striated muscle, but not by the neuron-specific gammagamma-enolase. These results support the idea that specific interactions with macromolecules will address muscle enolase isoforms at the subcellular site where ATP, produced through glycolysis, is most needed for contraction. Such a specific targeting could be modulated by post-translational modifications.

Animals↗

PubMed1997

Effects of riluzole on the evolution of focal cerebral ischemia: a magnetic resonance imaging study.

The aim of this study was to investigate the effects of riluzole on the lesion induced by a permanent middle cerebral artery occlusion (MCAO) in rats. Riluzole at 4 or 8 mg/kg i.v. significantly reduced the cortical ischemic brain damage. With the most effective dose of 8 mg/kg, the time evolution of the lesion was assessed by T2-weighted magnetic resonance imaging (MRI) repeated on the same animals after MCAO. MRI obtained at 24, 48, and 72 hours after MCAO showed a progressive increase of the ischemic lesion, except in the cortex of the riluzole-treated rats (8 mg/kg i.v.). Furthermore, there was no difference between lesion volumes as measured by MRI or by histology. This study indicates that MRI may be a valuable method to quantify in vivo the neuroprotective profile of a drug.

Animals↗

PubMed1997

Expression of two neuronal markers, growth-associated protein 43 and neuron-specific enolase, in rat glial cells.

Recent studies have revealed that proteins such as growth-associated protein 43 (GAP-43) and neuron-specific enolase (NSE), believed for many years to be expressed exclusively in neurons, are also present in glial cells under some circumstances. Here we present an overview of these observations. GAP-43 is expressed both in vitro and in vivo transiently in immature rat oligodendroglial cells of the central nervous system, in Schwann cell precursors, and in non-myelin-forming Schwann cells of the peripheral nervous system. GAP-43 mRNA is also present in oligodendroglial cells and Schwann cells, indicating that GAP-43 is synthesized in these cells. GAP-43 is also expressed in type 2 astrocytes (stellate-shaped astrocytes) and in some reactive astrocytes but not in type 1 astrocytes (flat protoplasmic astrocytes). These results suggest that GAP-43 plays a more general role in neural plasticity during development of the central and peripheral nervous systems. NSE enzymatic activity and protein and mRNA have been detected in rat cultured oligodendrocytes at levels comparable to those of cultured neurons. NSE expression increases during the differentiation of oligodendrocyte precursors into oligodendrocytes. In vivo, NSE protein is expressed in differentiating oligodendrocytes and is repressed in fully mature adult cells. The upregulation of NSE in differentiating oligodendrocytes coincides with the formation of large amounts of membrane structures and of protoplasmic processes. Similarly, NSE becomes detectable in glial neoplasms and reactive glial cells at the time when these cells undergo morphological changes. The expression of the glycolytic isozyme NSE in these cells, which do not normally contain it, could reflect a response to higher energy demands. This expression may also be related to the neurotrophic and neuroprotective properties demonstrated for this enolase isoform. NSE activity and protein and mRNA have also been found in cultured rat type 1-like astrocytes but at much lower levels than in neurons and oligodendrocytes. Thus GAP-43 and NSE should be used with caution as neuron-specific markers in studies of normal and pathological neural development.

Animals↗

PubMed1997

Internucleosomal breakdown of the DNA of brain cortex in human spongiform encephalopathy.

The analysis of chromatin structure in cases of human spongiform encephalopathies could show the possible involvement of apoptosis in neuronal cell death. Genomic DNA was purified from peripheral blood lymphocytes and from a biopsy of the brain cortex in a case of Creutzfeldt-Jakob disease. Restriction fragment polymorphism with AspI, PvuII, Del and NspI showed the pattern of wild type PrP gene. The DNA purified from the brain consisted of partially degraded DNA in internucleosomal-sized fragments, whereas the DNA from peripheral blood lymphocytes showed the high molecular weight of unbroken DNA. These results are consistent with the possible activation in vivo of the apoptotic endonuclease and the internucleosomal fragmentation of DNA of the brain cortex in the patient affected by Creutzfeldt-Jakob disease, suggesting the involvement of apoptosis in neuronal cell death in human spongiform encephalopathy.

Blood Cells↗

PubMed1997

A comparative study of the distribution of alpha- and gamma-enolase subunits in cultured rat neural cells and fibroblasts.

We report the presence and distribution of alpha (ubiquitous) and gamma (neuron-specific) subunits of the dimeric glycolytic enzyme enolase (2-phospho-D-glycerate hydrolase) in cultured neural cells. The gamma gamma enolase is found in vivo at high levels only in neurons and neuroendocrine cells. Neuronal cells in culture also contain relatively high levels of alpha gamma and gamma gamma enolase. Here we show, by enzymatic and immunological techniques, that the gamma subunit also is expressed in cultured rat astrocytes and meningeal fibroblasts and, as we previously reported, in oligodendrocytes. Both neuron-specific isoforms alpha gamma and gamma gamma are expressed in all these cells, but the alpha alpha isoform accounts for the major part of total enolase activity. The sum of alpha gamma and gamma gamma enolase activities increases with time in culture. i.e. maturation processes, reaching the highest level in oligodendrocytes (40% of total enolase activity) and 15 and 10% of total enzymatic activity in astrocytes and fibroblasts, respectively. The gamma enolase transcripts were found not only in cultured neuronal cells but also in cultured oligodendrocytes astrocytes, and meningeal fibroblasts. Our data indicate that neuron-specific enolase should be used with caution as a specific marker for neuronal cell differentiation.

Animals↗

PubMed1997

Highly informative single-stranded conformation polymorphism (SSCP) of short tandem repeats in DNA identification.

The analysis of short tandem repeats (STR) by PCR is a useful technique widely used in DNA identification. Some loci have alleles differing in the number of complete repeat units, whereas others are polymorphic with alleles differing even to the level of a single base. Minor differences in the sequence of STR can confuse the analysis when the PCR product are poorly resolved in denaturing PAGE. The study by SSCP of STR in loci CSF1PO, TPOX, and THO1 and the alleles of locus DIS80 is shown in a representative case of paternity dispute. The analysis of short tandem repeats (STR) by the conformation polymorphisms of single-stranded DNA (SSCP) clearly enhanced the degree of resolution. The high resolution of SSCP of the STR may be the result of the arrangement of very prominent secondary structure and conformation due to the primary repetitive sequence. The method may be of particular interest to distinguish STR with similar PAGE mobility under denaturing conditions and to distinguish tandem repeats of the same size but different sequence.

Alleles↗

PubMed1997

Synthesis and biological activities of higher homologues of retinoic acid.

Homoretinoic and bishomoretinoic acid have been synthesized. Fast reaction under ultrasonic activation (Wolff rearrangement, saponification) produced compounds in high yields. Only the bishomo analogue exhibits a significative activity alone and a synergistic effect with vitamin D3 on the differentiation of U937 leukemic cell line.

Antineoplastic Agents↗

PubMed1997

[Molecular genetic study in congenital myotonic dystrophy].

Congenital myotonic dystrophy (CMD) is the neonatal form of Steinert's myotonia. However, the symptoms and neuro-physiological findings are different from the classical adult form, there is a high mortality and early diagnosis of the condition is difficult. CMD occurs as a result of abnormal expansion of CTG triplets on chromosome 19. There is dominant autosomal transmission of this multi-systemic disorder, although when it occurs in children, it is the mother who is always the affected parent. Molecular genetic techniques enable unequivocal diagnosis of the condition, evaluation of anticipation and the possibility of offering genetic counselling to the families involved.

Chromosome Aberrations↗