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Biomedical subjects

C Lopez

Publications and source records attributed to C Lopez.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Evaluation of 20 years' experience of enuresis in children].

The clinical and urodynamic approach to enuretic children over a period of more than 20 years has allowed the authors to develop a multifactorial pathophysiological concept of this disorder. The main factors involved are psychological, familial, genetic, vesical, due to bladder immaturity, hormonal, due to a defect of nocturnal ADH secretion, hygiene and dietary habits, etc. The sleep factor is predominant in the majority of cases. Although nocturnal enuresis is apparently isolated in many cases, it is often associated with a state of bladder immaturity, sometimes latent during the day, but occurring at night with episodes of detrusor hyperactivity, occurring during various phases of sleep. In practice, the recognition, in children, of these factors, some of which require specific treatments, implies a management combining several of these therapeutic modalities.

Child↗
PubMed1996

Antisense oligonucleotide to the 70-kDa heat shock cognate protein inhibits synthesis of myelin basic protein.

Transfection of rat oligodendrocytes with an oligonucleotide sequence complementary to the mRNA encoding the initial ten amino acids of the rat 70-kDa heat shock cognate protein (HSC70) resulted in a rapid (within 24 h) and significant reduction in HSC70 synthesis (69% of control cells transfected with sense oligonucleotide). A further decrease to approximately 44% of controls was detected after 2 days. At that time, HSC70 protein content fell to approximately 49% of controls, and a significant reduction in the synthesis of myelin basic protein (MBP) was first detected (66% of controls). After 5 days, HSC70 synthesis returned to control levels. As HSC70 protein content recovered, so did the synthesis of MBP. Throughout the 5-day experimental period, only minor changes were detected in cell morphology, overall pattern of protein synthesis and the synthesis and content of proteolipid protein (PLP) and the pi isoenzyme of glutathione-S-transferase (pi). These data show that when HSC70 protein content is sufficiently reduced by antisense oligonucleotide, synthesis of MBP (but not PLP or pi) is correspondingly down-regulated, and provide evidence consistent with the role of HSC70 as a chaperone for MBP.

Animals↗
PubMed1996

The deleterious effects of human erythropoietin gene driven by the rabbit whey acidic protein gene promoter in transgenic rabbits.

Human erythropoietin (EPO) gene and cDNA associated with the rabbit whey acidic protein (WAP) gene promoter were used to tentatively produce the recombinant protein in milk of transgenic mice and rabbits. Several gene constructs showed good efficiency in the mouse mammary cell line HC11. None of them was able to direct the expression of the hormone at a concentration higher than 50 micrograms/mL in mouse and rabbit milk. With one of the construct, the rabbits had an abnormally high amount of red blood cells irrespectively of their sex, they could not reproduce and no milk could be obtained from them. These animals died prematurely. In these animals, the EPO gene was therefore expressed at a low but supraphysiological level in organs other than the mammary gland. These experiments show that transgenic animals obtained with gene constructs which do not contain insulators cannot be used as living fermentors to produce human erythropoietin in their milk at an industrial scale.

Animals↗
PubMed1996

1,000 consecutive ultrasounds for blunt abdominal trauma.

Diagnostic peritoneal lavage (DPL) and computed tomography (CT) are the primary diagnostic modalities used in the evaluation of patients with suspected blunt abdominal trauma (BAT). DPL is fast and accurate but is associated with complications. CT is also accurate, yet requires stability and transportability of the patients. Ultrasound (US) has been suggested as an aid in evaluating BAT. We evaluated US in the initial assessment of BAT in 1000 patients. Patients were eligible for the study if they met specified trauma criteria and had suspected BAT. We then followed the outcome of the patients and their further work-up. US showed a sensitivity of 88%, a specificity of 99%, and an accuracy of 97% for detecting intraabdominal injuries. We conclude that emergency ultrasound may be used as the initial diagnostic modality for suspected blunt abdominal trauma.

Abdominal Injuries↗
PubMed1995

Incorporation of sulphonated cyclodextrins into polypyrrole: an approach for the electro-controlled delivering of neutral drugs.

The electro-controlled delivery of drugs based on the doping-dedoping mechanism of Electro-Conducting Polymers is restricted to charged substances acting as dopants. In order to overcome this limitation, this study presents an approach where the trapping/delivering is based on host-guest interaction. As an example of a neutral guest, the molecule N-methylphenothiazine (NMP) is encapsulated in the host, heptasulphonated beta-cyclodextrin (beta-CDSO3-), which is tailor-made to dope PPy. The original synthetic method for beta-CDSO3- is based on sulphonation of the periodated beta-CD in the phase transfer medium. As a consequence of their size and of their multicharged character, beta-CDSO3-s are fixed dopants. The stability of the beta-CDSO3- entrapment is checked by Optical Beam Deflection (mirage effect) measurements. The ionic movements associated with the switching of the beta-CDSO3- doped PPy (PPy+, beta-CDSO3-) film appear to be mainly due to cations with this technique. Cyclic voltammetry experiments confirm the entrapment of neutral NMP by simply dipping the PPy+, beta-CDSO3- film in a CH3CN solution containing NMP. Repeated electrochemical cycling of such a reservoir electrode indicates the progressive elimination of NMP from the (PPy+, beta-CDSO3- [NMP]) film.

Cyclodextrins↗
PubMed1995

In vitro detection of specific IgE antibodies to erythromycin.

BACKGROUND: In vitro tests for detecting drug-specific IgE would be useful in identifying patients at risk for immediate hypersensitivity reactions to therapeutic doses of a drug. OBJECTIVE: We attempted to verify that IgE-mediated reactions to erythromycin occur and to identify IgE antibodies specific for erythromycin in serum from a patient who had urticaria immediately after administration of the drug. METHODS: Skin prick testing was performed on the patient and five control subjects. Serum from the patient, pooled sera from nonatopic subjects allergic to common aeroallergens, and cord blood controls were analyzed for erythromycin-specific IgE by radioimmunoassay. Sepharose (Pharmacia, Uppsala, Sweden) was used as solid phase covalently linked to erythromycin. RESULTS: We were able to detect erythromycin-specific IgE antibodies in serum from the patient who had an allergic reaction to this antibiotic, but specific IgE could not be detected in control sera. CONCLUSION: Immunologic IgE-mediated reactions to erythromycin do occur, and in vitro diagnosis of such reactions can be made by using Sepharose as a solid phase covalently linked to this drug.

Adult↗
PubMed1995

Acetabular reconstruction using structural grafts in total hip replacement: a 12 1/2 year follow-up.

We reviewed 34 patients who had structural acetabular grafts used in conjunction with total hip replacement. Two patients died and eight were lost to follow-up, leaving 24 patients with 24 grafts who were followed-up for a minimum of 10 years and an average of 12 1/2 years. There were 8 primary hips and 16 revisions. Twenty-two (92%) of the grafts united. The two non-unions were in patients with sepsis. Six grafts (26%) failed. Two failed because of sepsis and four were aseptic failures. All the aseptic failures were the results of technical errors. Two grafts were of poor quality and all of the aseptic failures had transverse trabeculae and transverse screws. There were 10 (41%) loose acetabular components. Two were loose because of sepsis. Of the eight aseptic failures, four were caused by failure of the graft and in the other four, the graft remained intact but the cemented acetabular components loosened. There was no correlation between the percentage of component coverage by the graft and component failure. The average preoperative Harris rating was 43 and the postoperative rating was 81, including the failures. If the failures were eliminated, the rating of the remaining patients was 93. Structural acetabular grafts are rarely necessary. However, they do work and their success is clearly related to technique. Important technical factors include: the graft must be of good quality, the trabecula must be oriented in the line of weight-bearing forces, the graft must accurately fit the defect, the graft must be supported by a host buttress, and the graft should be fixed with lag screws that are oriented in a line of weight-bearing. If these criteria are met, early weight-bearing is important to stimulate graft healing and remodeling.

Acetabulum↗
PubMed1995

Comparison of Petrifilm method to conventional methods for enumerating aerobic bacteria, coliforms, Escherichia coli and yeasts and molds in foods.

The Petrifilm plates method was compared to conventional methods (PCA, VRBA, Levine EMB agar and OGYE agar) for enumeration of mesophilic aerobic bacteria, coliforms, Escherichia coli, and yeasts+molds in six homogeneous lots of different food groups (pasteurized milk, yoghurt ice cream, eggs, minced meat, fresh strawberries and frozen green beans). For all the microbiological criteria except for yeasts and molds and mesophilic aerobic bacteria in frozen green beans, the mean values of counts with Petrifilm plates were higher than those obtained with traditional methods. The correlation coefficient of Petrifilm aerobic bacteria, coliforms, and yeasts + molds v. PCA, VRBA and OGYE agar for each microbiological criterion for a composite of six food products were 0.897, 0.861 and 0.981, respectively.

Bacteria, Aerobic↗
PubMed1994

Efficient production of biologically active human recombinant proteins in human lymphoblastoid cells from integrative and episomal expression vectors.

The ability of human lymphoblastoid cells to secrete large amounts of biologically active human hematopoietic growth factors from adenovirus-based expression vectors was investigated. The gene for human erythropoietin (EPO) was inserted into integrative (pTS39) and episomal (pTS53) vectors. Cell clones, originating from pTS39 or pTS53-transfected and stably selected cells, secreted recombinant human EPO (re-hEPO) at similar levels. The highest production, 60 mu/10(6) cells per 24 h, was obtained from a subclone of pTS39-transfected cells, grown in nonselective medium. The re-hEPO was shown to be biologically active in vivo by incorporation of 59Fe into red blood cells of polycythemic mice and in vitro by the proliferative response of the EPO-dependent cell line UT7. The purified protein of 36 kDa in SDS-PAGE slightly differed from re-hEPO from CHO cells. pTS39 vector was integrated at 15-30 copies per genome, whereas the pTS53 vector replicated at 10 copies per cell. Genes encoding human interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were also expressed in the integrative system as biologically active growth factors, demonstrating that our host-vector system allows the expression of any little gene or cDNA and efficient secretion of the re-protein produced.

Animals↗
PubMed1994

Purification and biological activity of a recombinant human erythropoietin produced by lymphoblastoid cells.

A recombinant human erythropoietin (rH-EPO) was obtained from the culture supernatants of human B-lymphoblastoid cells transfected by the human EPO gene. rH-EPO was purified by a two-step method based on immunoaffinity and ion exchange chromatography. The first step was achieved by an anti-EPO monoclonal antibody (Mab). This Mab, immobilized on Sepharose 4B, allowed a 410-fold purification of the protein. The second step consisted of ion exchange chromatography on DEAE Sephacel. The combination of these two steps results in a highly purified rH-EPO with a global yield of about 50%; the specific activity of the protein was 176,000 IU/A280. The NMR spectrum was characteristic for a well structured, single-conformation protein. The purified protein was analyzed by SDS-PAGE and isoelectric focusing. The biological activity of purified rH-EPO was measured in vivo, by the incorporation of 59Fe into red blood cells (RBC) of polycythemic mice and in vitro by the proliferative response of an EPO-dependent cell line. The purified protein expressed in lymphoblastoid cells of human origin had the same biological activity as that of urinary EPO and rH-EPO produced in other mammalian cells.

Amino Acid Sequence↗
PubMed1994

Value of PCR detection of TCR gamma gene rearrangement in the diagnosis of cutaneous lymphocytic infiltrates.

In this study, we analyzed the reliability and usefulness of the polymerase chain reaction (PCR) for the detection of T-cell receptor (TCR)gamma gene monoclonal rearrangement. We first tested for the specificity and sensitivity of this strategy, against the classical criteria of Southern blot analysis (SBA). Of the 27 samples tested, results agreed in all but two. Broader analysis of these cases demonstrated the high specificity (absence of false positives) of the PCR strategy, together with its limited sensitivity (10% of false negatives). The usefulness of this PCR approach was then tested on a panel of 28 biopsy specimens of cutaneous lymphocytic infiltrates. Monoclonal TCR gamma rearrangement was detected in seven of eight cases of early stage mycosis fungoides (MF), one of two Sezary syndrome (SS) cases, two of two non-MF T-cell lymphoma, and two of three lymphomatoid papulosis. Monoclonality was not detected in any of the 11 benign cases (parapsoriasis and inflammatory dermatosis). Results obtained with this new molecular strategy provide additional support for the hypothesis of a monoclonal origin for most early stage T-cell MF. They also suggest the heterogeneous nature of some lymphomatoid papulosis lesions. Therefore, due to the difficulty in detecting T-cell monoclonality by immunohistochemical techniques, PCR can be a useful alternative strategy to SBA. It could also be used as a complementary technique in the routine diagnosis of T-cell cutaneous infiltrates.

Adolescent↗
PubMed1993

The expression of p53 protein in non-Hodgkin's lymphomas is not always dependent on p53 gene mutations.

p53 overexpression has been found to be a fairly common feature in high grade lymphomas in the majority of tumoral cells. The results vary from series to series, from 25% to 33% of cases. To assess whether immunohistochemical positivity for p53 correlated with the presence of structural gene abnormalities, DNA from 16 non-Hodgkin's lymphomas with high and low p53 values was amplified and sequenced to determine the existence of point mutations in the highly conserved regions of the p53 gene. In the group of 8 cases containing high levels of protein, 3 cases showed missense point mutations at the codons mapping between exons 5 through 8. Of the 8 cases of tumors containing undetectable or low levels of p53 protein, 1 case presented a nonsense point mutation giving a stop codon. No missense mutations were detected in this group. The finding of p53 mutations in 4 of 16 cases confirms the presence of p53 gene mutations in high grade lymphomas distributed over different histologic groups. These include Burkitt's lymphoma, together with centroblastic, immunoblastic, and large cell lymphoma of mucosa origin. Nevertheless, the absence of mutations in 5 of the 8 cases that overexpressed p53 suggests that the nuclear or cytoplasmic stabilization of p53 protein could also depend on other factors. The absence of detectable levels of p53 protein cannot discount the existence of p53 mutations, as is shown by a case of Burkitt's lymphoma in which a nonsense mutation was detected. The impact of this range of p53 alterations on clinical course and treatment response of the patients deserves to be explored, in an attempt to differentiate the specific consequences of each one.

Base Sequence↗
PubMed1993

Microbiological quality of French yogurts commercialized in Spain.

The microbiological quality has been evaluated in 6 batches of yogurt (plain, flavoured and fruit-added) produced commercially in France and purchased in Spain. The essential microflora: Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, and contaminants (coliform bacteria, yeasts and molds) were checked. The pH was also measured. The totality of the samples tested fulfilled French and Spanish regulation with respect to the presence of viable yogurt organisms. Likewise, in 100% of the yogurts, counts of contaminants were under 10 cfu/g. The pH ranged between 3.92 and 4.19.

Animals↗
PubMed1992

Induction of host cell protein synthesis by human herpesvirus 6.

We observed an increase in host cell protein synthesis in human cord blood lymphocytes (CBL) infected with human herpesvirus 6 relative to uninfected cultures. The magnitude of this effect could not be explained by a smaller decrease in cell number in the infected cultures. The induction of host cell protein synthesis by HHV-6 does not appear to be mediated by a stable soluble factor present in the infected cell culture supernatant. When CBL were infected with virus that had been exposed to ultraviolet irradiation (UV) for various intervals, we found that the level of increase in cell number, host protein synthesis, viral DNA and viral antigen was inversely proportional to the length of time of virus exposure to UV. No increase in cell number or host cell protein synthesis was seen in CBL infected in the presence of 50 micrograms/ml phosphonoacetic acid, an inhibitor of HHV-6 DNA replication. These results indicate that components of input virions do not induce the increased protein synthesis and that the induction is dependent on viral DNA replication.

Biological Factors↗
PubMed1991

[Cancer of the ovary].

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Antineoplastic Combined Chemotherapy Protocols↗