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Biomedical subjects

R Lopez

Publications and source records attributed to R Lopez.

At least 55 records · Page 3Linked to original sources
PubMed2000

Functional parathyroid hormone receptors are present in an umbilical vein endothelial cell line.

Acute parathyroid hormone exposure induces vascular smooth muscle relaxation. In contrast, continuous infusion of parathyroid hormone leads to vasoconstriction and an elevation of blood pressure. Despite the known effects of parathyroid hormone on vascular smooth muscle, possible direct effects on the vascular endothelium have not previously been investigated. Using a human umbilical vein endothelial cell line, we found that parathyroid hormone increased both intracellular calcium and cellular cAMP content in these endothelial cells. Furthermore, exposure of these cells to increasing concentrations of parathyroid hormone stimulated both [(3)H]thymidine incorporation and endothelin-1 secretion. Parathyroid hormone/parathyroid hormone-related peptide receptor mRNA could be detected at low levels in these cells. In summary, these data demonstrate that endothelium-derived cells contain functional parathyroid hormone receptors. The potential physiological role of these receptors remains to be determined.

Calcium↗
PubMed2000

[Tolerance, reliability and efficiency of inflatable breast implants after breast reconstruction. Retrospective study of 101 consecutive cases].

A long-term retrospective study of breast reconstruction with inflatable implants is presented. One hundred and one patients were studied, with a median follow-up of 44 months. Prosthetic implants used were round McGhan implants, model 168. Median volume was 215 mL. Twenty-two patients had contralateral symmetrisation, an average of five months after implant. The advantages of this sort of reconstruction are ease, speed and homogenously good results. Drawbacks include the appearance of prosthetic leaks (7%), waves and folds (13%), stage III and IV capsular contractures (26%), asymmetry and incorrect placement of the implant (25%). Breast reconstruction with implants alone gives good results for specific indications: immediate reconstructions, bilateral reconstructions, no history of radiotherapy, and good quality chest wall tissues.

Adult↗
PubMed2000

[Interest of periareolar injection for colorimetric detection of sentinel node in breast cancer].

Most teams working on sentinel node biopsy in the treatment of breast cancer inject either radioactive colloid or vital blue dye around the primary tumour. Many anatomical studies and lymphoscintigraphical studies, some very old, have shown that the lymphatic drainage of the breast is collected first in the periareolar plexus of Sappey, then routed to the axilla in 95% of cases, via one or two primary collectors. In a series of 94 breast cancers measuring less than 3 cm, with any palpable axillary lymph node, 2 ml of patent blue was injected intradermally around the areola, at the two meridians around the tumor. The sentinel node was identified in 89 cases (94,7%), regardless of the location of the primary tumor. All the sentinel nodes were located in the lower axilla. An average of 1.6 nodes were found per patient. In 41 cases, axillary lymph node dissection was performed either immediately (5 technical failures, 9 positive frozen section) or delayed only if the sentinel node was positive, either on standard H&E staining or on immunohistochemistry (27 cases). Thus, axillary lymph node dissection was not performed in 48 patients (55%). In positive node patient, the sentinel node was the only positive lymph node in 20 patients (55%). For 5 positive node patients, axillary lymph node dissection was not performed: poor vital status (2 micro-metastatic nodes) or by decision of patient (3 IHC positive nodes). With this periareolar injection procedure, the rate of detection is highly satisfactory and is comparable to that usually published with peritumoral injection. This procedure seems appropriate in all cases, regardless of the topography, the size or the multifocality of breast cancer.

Axilla↗
PubMed2000

Marfan syndrome in a female collegiate basketball player: a case report.

OBJECTIVE: To present the case of an elite female basketball player with Marfan syndrome diagnosed after a heart murmur was found on preparticipation screening examination. BACKGROUND: Undetected Marfan syndrome can result in sudden death during competition or practice. While those with Marfan syndrome often present with characteristic skeletal and ocular manifestations, the condition can go unnoticed if the athlete is not exceptionally lean. DIFFERENTIAL DIAGNOSIS: Homocystinuria. TREATMENT: After a heart murmur was detected on a preparticipation examination, the athlete was referred to a cardiologist, who advised the athlete to discontinue vigorous athletic activity and undergo surgery to replace the ascending aorta and aortic valve with a composite graft tube and valve. She is presently waiting to undergo surgery. UNIQUENESS: The athlete had neither an ectomorphic body build nor a family history of Marfan syndrome. CONCLUSIONS: ATHLETIC TRAINERS CAN PLAY AN IMPORTANT ROLE IN THE EARLY DETECTION OF MARFAN SYNDROME VIA A SIMPLE SCREENING PROCEDURE: comparing the athlete's arm span and height.

Journal Article↗
PubMed1999

Novel bioartificial liver support system: preclinical evaluation.

Preclinical safety and efficacy evaluation of a novel bioartificial liver support system (BLSS) was conducted using a D-galactosamine canine liver failure model. The BLSS houses a suspension of porcine hepatocytes in a hollow fiber cartridge with the hepatocytes on one side of the membrane and whole blood flowing on the other. Porcine hepatocytes harvested by a collagenase digestion technique were infused into the hollow fiber cartridge and incubated for 16 to 24 hours prior to use. Fifteen purpose-bred male hounds, 1-3 years old, 25-30 kg, were administered a lethal dose, 1.5 g/kg, of D-galactosamine. The animals were divided into three treatment groups: (1b) no BLSS treatment (n = 6); (2b) BLSS treatment starting at 24-26 h post D-galactosamine (n = 5); and (2c) BLSS treatment starting at 16-18 h post D-galactosamine (n = 4). While maintained under isoflurane anesthesia, canine supportive care was guided by electrolyte and invasive physiologic monitoring consisting of arterial pressure, central venous pressure, extradural intracranial pressure (ICP), pulmonary artery pressure, urinary catheter, and end-tidal CO2. All animals were treated until death or death-equivalent (inability to sustain systolic blood pressure > 80 mmHg for 20 minutes despite massive fluid resuscitation and/or dopamine administration), or euthanized at 60 hours. All animals developed evidence of liver failure at 12-24 hours as evidenced by blood pressure lability, elevated ICP, marked hepatocellular enzyme elevation with microscopic massive hepatocyte necrosis and cerebral edema, elevated prothrombin time, and metabolic acidosis. Groups 2b and 2c marginally prolong survival compared with Group 1b (pairwise log rank censored survival time analysis, p = 0.096 and p = 0.064, respectively). Since survival times for Groups 2b and 2c are not significantly different (p = 0.694), the groups were combined for further statistical analysis. Survival times for the combined active treatment Groups 2b and 2c are significantly prolonged versus Group 1b (p = 0.047). These results suggest the novel BLSS reported here can have a significant impact on the course of liver failure in the D-galactosamine canine liver failure model. The BLSS is ready for Phase I safety evaluation in a clinical setting.

Animals↗
PubMed1999

The EMBL Nucleotide Sequence Database.

The EMBL Nucleotide Sequence Database (http://www.ebi.ac.uk/embl.html) constitutes Europe's primary nucleotide sequence resource. Main sources for DNA and RNA sequences are direct submissions from individual researchers, genome sequencing projects and patent applications. While automatic procedures allow incorporation of sequence data from large-scale genome sequencing centres and from the European Patent Office (EPO), the preferred submission tool for individual submitters is Webin (WWW). Through all stages, dataflow is monitored by EBI biologists communicating with the sequencing groups. In collaboration with DDBJ and GenBank the database is produced, maintained and distributed at the European Bioinformatics Institute (EBI). Database releases are produced quarterly and are distributed on CD-ROM. Network services allow access to the most up-to-date data collection via Internet and World Wide Web interface. EBI's Sequence Retrieval System (SRS) is a Network Browser for Databanks in Molecular Biology, integrating and linking the main nucleotide and protein databases, plus many specialised databases. For sequence similarity searching a variety of tools (e.g. Blitz, Fasta, Blast etc) are available for external users to compare their own sequences against the most currently available data in the EMBL Nucleotide Sequence Database and SWISS-PROT.

Amino Acid Sequence↗
PubMed1999

Macrophage Fcgamma receptors expression is altered by treatment with dopaminergic drugs.

Macrophage Fcgamma receptors have an important role in host defense and the pathophysiology of immune mediated disorders. Alteration of splenic macrophage Fcgamma receptors expression predisposes to severe infection. Inhibition or blockade of splenic macrophage Fcgamma receptors is one of the mechanisms by which immune cytopenias improve. Dopaminergic drugs have clinically significant regulatory functions on the immune response. Using an experimental model in the guinea pig we assessed the effect of commonly used dopaminergic drugs on the expression of macrophage Fcgamma receptors. Three dopa-antagonists, bromocryptine, leuprolide, and pergolide, and seven dopa-antagonists, chlorpromazine, SCH 23390, metochlopramide, sulpiride, veralipride, alizapride, and cisapride, were studied. Following guinea pig treatment with dopaminergic drugs, the clearance of IgG-sensitized RBCs in vivo, the in vitro binding of IgG-sensitized RBCs by isolated splenic macrophages and flow cytometry with monoclonal antibodies were performed. Treatment with dopa-agonists enhanced the clearance of IgG-sensitized RBCs, the in vitro binding of IgG-sensitized RBCs by isolated splenic macrophages, and the cell surface expression of both macrophage Fcgamma receptors, and vice versa, dopa-antagonists impaired macrophage Fcgamma receptors expression. Macrophage FcgammaR1,2 was more sensitive than FcgammaR2 to such dopaminergic effect. These alterations of macrophage Fcgamma receptors expression are mediated by both D1 and D2 dopamine receptors, with a major participation of D2 receptors. Dopaminergic drugs alter the clearance of IgG-coated cells by an effect at the expression of splenic macrophage Fcgamma receptors.

Animals↗
PubMed1999

Paediatric intracranial aneurysms: results of a surgical series and literature review of Guglielmi detachable coil embolization.

It is known that the profile of aneursyms in the paediatric age group demonstrates a different biology and epidemiology than those in the adult population in terms of size, sex, location, multiplicity and complications such as vasospasm and rebleeding. As a consequence of their different behaviour, timing of surgery does not appear to be such a critical issue in their management decision. Surgical clipping is still the treatment of choice, however, with our growing experience of endovascular techniques, these might prove to be a suitable alternative in the future. We report the results of our surgical series of 17 paediatric and adolescent patients harbouring 18 arterial intracranial aneurysms (age range 7-18 years). Systemic diseases traditionally known to be associated with this entity were excluded. In order to assess endovascular techniques as a potential treatment alternative for this group of patients, we reviewed the current literature, dealing with Guglielmi detachable coil (GDC) embolization of arterial cerebral aneurysms in this age group. No current series deals purely with paediatric aneurysms; we have reviewed paediatric cases reported as part of large adult series. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗
PubMed1999

Association of primary Pneumocystis carinii infection and sudden infant death syndrome.

To delineate clinical and histological features of the first Pneumocystis carinii infection affecting the immunocompetent host, P. carinii-specific histological stains were performed on autopsy lung specimens from 534 consecutive pediatric patients (those with AIDS and malignancies were excluded) in Santiago, Chile. P. carinii clusters were found in 4 (25%) of 16 infants who died of no apparent cause at arrival to the emergency department, and in 10 (2.9%) of 342 infants who died of multiple conditions at the hospital (P=.002, Fisher's exact test). This prompted us to analyze additional series of infants with sudden infant death syndrome (SIDS). In 161 additional SIDS cases, 47 (35.1%) of 134 infants from Chile and 4 (14.8%) of 27 infants from Oxford, United Kingdom, were found to have P. carinii clusters in the lungs. The quantity of P. carinii cysts was small compared with the numbers seen in immunocompromised hosts with P. carinii pneumonitis. This study provides histological evidence that primary P. carinii infection is associated with SIDS.

Autopsy↗
PubMed1999

Synchronous laparoscopic vasectomy and hernia repair.

Over the last few years, general surgery has seen the use of more and more laparoscopic techniques in the management of common surgical problems. This expanded use is attributable not only to the excellent results seen with laparoscopic procedures but also to patient demand. A 48-year-old man requested a laparoscopic hernia repair with synchronous vasectomy. The technique of synchronous laparoscopic hernia repair and vasectomy is discussed, and a literature review is provided. Certain disadvantages along with the difficulty in reanastomosis after a laparoscopic vasectomy will prevent the replacement of traditional vasectomy with the laparoscopic technique.

Hernia, Inguinal↗
PubMed1999

[A zinc sulfate and usnic acid preparation used as post-surgical adjuvant therapy in genital lesions by Human Papillomavirus].

BACKGROUND: To evaluate the efficacy and safety of intravaginal administration of a zinc sulphate and usnic acid compound as adjuvant therapy of Human Papillomavirus (HPV) genital infection, after radiosurgical treatment (RS). METHODS: One hundred patients affected by HPV genital infection were enrolled in the study from October 1996 to July 1998. Patients were classified according to colposcopic and cytologic criteria and treated with RS. Patients were randomized into three groups: the first group did not follow any therapy after RS (control group), (n = 50); the second group was pharmacologically treated with intravaginal administration of a usnic acid and zinc sulphate compound (Zeta N, Bergamon Italia) before and after RS (n = 25), the third group was pharmacologically treated only after RS (n = 25). The last two groups were considered together for the statistical analysis. Patients were reevaluated after one, two, three and six months from electrocoagulation. The safety of treatment was also investigated. RESULTS: One month after RS. HPV lesions disappeared in 93% of the patients in the control group and in 100% of patients treated with usnic acid and zinc sulphate. After one month, reepithelization was complete in 65% of cases treated with usnic acid and zinc sulphate and in only 28% of the control group (p = 0.001). Two months later reepithelization was 94% in the patients pharmacologically treated compared to 76% of the control group (p = 0.06). Treatment prior to RS resulted in a reduction of the overall area of lesions in 88% of cases. Three months after RS, there was a significant reduction of recurrence in the group treated with usnic acid and zinc sulphate (p = 0.01). This reduction was still significant at six months (p = 0.005). CONCLUSIONS: Usnic acid and zinc sulphate adjuvant treatment improved time of reepithelization and reduce the recurrence with few side effects and a good compliance.

Adult↗
PubMed1998

Amphotericin B determination in respiratory secretions by reversed-phase liquid chromatography.

Direct delivery of amphotericin B (AMB) to the respiratory tract may be an alternative to intravenous administration. The use of inhalation allows high AMB concentrations to be achieved at the site of infection. A reversed-phase high-performance liquid chromatographic method with a 30-mm-long column is described for assaying AMB in respiratory secretions obtained by bronchoaspiration (BAS) and bronchoalveolar lavage (BAL). Sample clean-up involved treatment with methanol (BAS) and solid-phase extraction onto Sep-Pak C18 cartridges (BAL). The mobile phase consisted of 2.5 mM Na2EDTA-acetonitrile (70:30, v/v). The retention time of AMB was 1.5 min. The range of the assay was from 0.1 to 5 micrograms/ml. The mean recovery was over 90% for both fluids. Within-day and between-day RSDs ranged from 3.10 to 11.87%. AMB in the BAS samples was stable for two days at 20-25 degrees C and for three months at -20 degrees C. The drug in the BAL fluid was stable for one day at 20-25 degrees C, seven days at 4 degrees C and for one month at -20 degrees C.

Amphotericin B↗
PubMed1998

Treatment with progesterone analogues decreases macrophage Fcgamma receptors expression.

Macrophage Fcgamma receptors (FcgammaRs) are critical for host defense against infection and have an important role in immune cytopenias. Modulation of macrophage FcgammaRs expression is a potential therapeutic approach to immune disorders. Glucocorticoids and synthetic progesterone analogues decrease macrophage FcgammaRs expression. We assessed the effect of treatment with commonly employed progestins on the expression of macrophage FcgammaRs using an experimental model in the guinea pig. Eight clinically available progesterones, medroxyprogesterone acetate (P3), megestrol acetate (P4), medrogestone (P5), alylestrenol (P6), linestrenol (P7), didrogesterone (P8), norethisterone (P9), and gestonorone caproate (P10) and two endogenous progesterones, progesterone (P1) and 17 alpha-hydroxyprogesterone (P2), were studied. Following in vivo treatment of guinea pigs, we determined the clearance of IgG-sensitized erythrocytes in vivo, the binding of IgG-sensitized erythrocytes by isolated splenic macrophages, and splenic macrophage Fcgamma receptor cell surface expression. All progesterones impaired the clearance of IgG-sensitized erythrocytes by decreasing splenic macrophage Fcgamma receptor expression. P5, P6, P7, and P8 were less effective. Flow cytometry and fluorescence microscopy with monoclonal antibodies demonstrated that progesterones decreased the cell surface expression of FcgammaR2 more than that of FcgammaR1,2. Clinically employed progestins impair the clearance of IgG-coated cells by decreasing splenic macrophage FcgammaRs expression. Thus, progesterones are candidate drugs for the treatment of immune disorders.

Animals↗
PubMed1998

Influence of posttransplant time on dose and concentration of tacrolimus in liver transplant patients.

The dosage of tacrolimus (D), the trough blood concentrations (C) and the evolution of the D/C ratio were followed for 1 year after transplantation in so adult patients (38 males and 12 females) undergoing liver allograft. A total of 1489 samples were analysed by the IMx tacrolimus method. The overall median concentration was 11.27 ng/ml. During the 1st month the median of the tacrolimus levels was 8.4 ng/ml, and 73.1% of the analysed samples were within the established therapeutic range. The median oral tacrolimus dose was progressively reduced from 0.12 mg/kg per day during the 1st month to 0.06 mg/kg per day at the end of studied period. A significant negative association was observed between the D/C ratio and the post-transplantation period (r = -0.3892; P < 0.0001). The median D/C ratio ranged from 0.0144 at 1st month to 0.0053 at 1 year. Significant D/C declines were observed after the 1st and 3rd months posttransplant. The decrease in corticosteroid doses and the increase in serum albumin may explain the reduction in clearance with time.

Adult↗
PubMed1998

Effects of antidepressant treatment on inhibitory avoidance behavior and amygdaloid beta-adrenoceptors in rats.

Chronic treatment of rats with a variety of antidepressants results in the down-regulation of beta-1-adrenoceptors in the amygdaloid nuclei. The present study sought to determine if this specific neurochemical effect caused an alteration in inhibitory avoidance conditioning, a behavior considered to be mediated by beta-adrenoceptors in the amygdala. Rats treated chronically with either desipramine (DMI) or phenelzine (PHEN), which down-regulate beta-1-adrenoceptors in the amygdala, or fluoxetine (FLUOX), which does not do this, did not exhibit a deficit in the retention of the inhibitory avoidance task. However, when scopolamine was given prior to acquisition of the task in a dose that, by itself, did not affect retention, DMI- and PHEN-treated rats showed a marked deficit in retention. This effect was also observed after acute administration of these drugs, although they did not down-regulate amygdaloid beta-1-adrenoceptors at this time. It seems that the ability of these antidepressants to potentiate the amnesic effect of scopolamine is unrelated to their effect on beta-1-adrenoceptor number in the amygdala and that the extent of the antidepressant-induced amygdaloid beta-1-adrenoceptor down-regulation is not sufficient, by itself, to cause a deficit in an inhibitory avoidance task.

Adrenergic beta-Antagonists↗
PubMed1998

Microinvasive laparoscopic cholecystectomy in pediatric patients.

Although cholelithiasis is uncommon in children, its laparoscopic treatment has progressively become more popular among pediatric surgeons. This is due in part to the fact that compared with the open technique, laparoscopic treatment is less invasive as well as more cost-effective. A review of the literature indicates that it has been customary to use at least one 10-mm port to permit application of the 10-mm endoscopic clip applier for ligation of the cystic duct and artery. We report our experience with two patients in whom a laparoscopic cholecystectomy was performed by use of a 5-mm endoscopic clip applier and a 3-mm laparoscope. The application of a 5-mm clip applier obviated the need for a 10-mm port. It also saved an additional step by eliminating the exchange from the laparoscope to the 10-mm endoscopic clip applier through the 10-mm port. Furthermore, the use of a 3-mm telescope through the smallest port (<5 mm) would achieve a better cosmetic outcome.

Child↗
PubMed1998

Therapeutic drug monitoring of tacrolimus in liver transplantation, phase III FK506 multicenter Spanish Study Group: a two-year follow-up.

The aim of the Multicentric Liver Transplant Spanish Study was to evaluate tacrolimus therapy at the reduced, initial oral dose of 0.1 mg/kg per day to maintain the immunosuppressive potency of the drug and to avoid toxicity. The dosage of tacrolimus (D), the trough blood concentrations (C), and the evolution of the ratio (D/C) were followed up for 2 years after transplantation in 50 adult patients (38 men, 12 women) undergoing liver allograft transplantation. A total of 1732 samples were analyzed using the IMx tacrolimus method. The overall mean+/-SD concentrations were 10.84 ng/ml+/-5.32 ng/ml. During the first month, the median of the tacrolimus levels was 8.40 ng/ml, and 73.1% of the analyzed samples were within the established therapeutic range. The median oral tacrolimus dose was progressively reduced from 0.12 mg/kg per day during the first month to 0.058 mg/kg per day at the end of study period. A significant negative association was observed between the ratio of D/C and the post-transplantation period (r=-0.3624; p < 0.001). The median D/C ratio ranged from 0.0144 at the end of the first month to 0.0053 at 1 year. Significant declines in D/C were observed after the first and the third months after transplantation. The decrease in corticosteroid doses and the increase in serum albumin may explain the reduction in clearance with time.

Adult↗