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Biomedical subjects

L Gutierrez

Publications and source records attributed to L Gutierrez.

At least 19 recordsLinked to original sources
PubMed2006

Pinoresinol-lariciresinol reductase gene expression and secoisolariciresinol diglucoside accumulation in developing flax (Linum usitatissimum) seeds.

The transcription activity of the pinoresinol-lariciresinol reductase (PLR) gene of Linum usitatissimum (so-called LuPLR), a key gene in lignan synthesis, was studied by RT-PCR and promoter-reporter transgenesis. The promoter was found to drive transcription of a GUSint reporter gene in the seed coats during the flax seed development. This fitted well with the tissue localization monitored by semi-quantitative RT-PCR of LuPLR expression. Accumulation of the main flax lignan secoisolariciresinol diglucoside was coherent with LuPLR expression during seed development. This three-way approach demonstrated that the LuPLR gene is expressed in the seed coat of flax seeds, and that the synthesis of PLR enzyme occurs where flax main lignan is found stored in mature seeds, confirming its involvement in SDG synthesis.

Base Sequence↗
PubMed2005

Sustained availability of trimethoprim in drinking water to achieve higher plasma sulphonamide-trimethoprim antibacterial activity in broilers.

(1) In order to make trimethoprim (TMP) available to broilers throughout the day, a sustained release formulation (SRF) of the drug in the form of granules was added to the water tank that supplies drinking water. (2) Broilers were initially dosed with sulphachloropiridazine-TMP (SCP-TMP 5:1) and then further medicated throughout the day, achieving in the end a dose of 30 mg/kg each of SCP and TMP (group A). Group B received a preparation with the same dose of SCP and TMP (1:1) as group A, but administered as a single dose without the SRF of TMP. Group C received the customary SCP-TMP 5:1 preparation (30 and 6 mg/kg, respectively). Water tanks were completely consumed in 3 to 4 h. (3) Broilers were bled at different times and concentration of antibacterial activity in serum determined by correlating the composite antibacterial activity of SCP and TMP with actual concentrations of these drugs by means of a microbiological agar diffusion assay. (4) Time vs serum concentrations of activity were higher in group B; the increments in the maximum serum concentration for group B over groups A and C being 39 and 67%, respectively. (5) However, the sustained concentration of activity over time, measured as the area under the cu)rve, was highest in group A. Group B had higher values for area under the curve than group C. (6) An additional dose of TMP to achieve 30 mg/kg of both SCP and TMP improves the serum concentration of this combination over the customary 5:1 proportion. The best values for sustaining antibacterial activity were obtained using a 1:1 ratio as in group A. The use of a SRF as in group A may translate into better clinical results.

Absorption↗
PubMed2004

Serum activity/concentration profiles of a sustained-released formulation of sulphathiazole-trimethoprim (2.5:1) in calves.

Thirty-six two-week-old healthy Holstein-Friesian calves weighing between 52 and 58 kg were divided at random into three groups of 12; group A calves were given a single oral bolus containing 2.5 g sulphathiazole and 1 g trimethoprim in a sustained-release formulation; group B received the same doses of the drugs but the trimethoprim was not in a sustained-release formulation; group C received a bolus containing 2.5 g sulphathiazole and 0.5 g conventional trimethoprim. Blood samples were collected at intervals for two days, the serum was separated and the composite antibacterial activity profiles of the mixture were analysed by an agar-diffusion microbiological method. The mean maximum activities in the serum of the three groups were 23.4 microg/ml in group A, 9.25 microg/ml in group B and 8.01 microg/ml in group C. The mean areas under the curves of the serum activity time curves were 838 microg/ml/hour in group A, 216 microg/ml/hour in group B and 182 microg/ml/hour in group C.

Animals↗
PubMed2003

Antisense transgenesis of tobacco with a flax pectin methylesterase affects pollen ornamentation.

Antisense transgenesis of tobacco (Nicotiana tabacum) with a partial flax (Linum usitatissimum L.) pectin methylesterase (Lupme3) cDNA sequence yielded plants with altered pollen content. Moreover, the characteristically sculptured cell wall surrounding the pollen grains was modified in transgenic tobacco plants: the wavy ornamentation was dramatically reduced, suggesting the involvement of the demethylation of pectin in the pollen cell wall-specific structure. Germination of pollen was decreased and the pollen tube surface aspect was also different in transgenic plants.

Carboxylic Ester Hydrolases↗
PubMed2001

Interleukin 8 production and interleukin 8 receptor expression in human myometrium and leiomyoma.

OBJECTIVE: Interleukin 8 is a potent chemoattractant cytokine that is expressed in a variety of human tumors and is known to induce mitogenesis. We aimed to investigate the production of interleukin 8 and the expression of its receptor in myometrium and leiomyoma, in which we hypothesized that interleukin 8 may contribute to cellular proliferation. STUDY DESIGN: Myometrial and leiomyoma tissue pairs (n = 14) were obtained from human uteri after hysterectomy conducted for leiomyomatous uterus. Expression of interleukin 8 and interleukin 8 receptor type A was identified in the leiomyomatous myometrium by means of specific antibodies directed against interleukin 8 and interleukin 8 receptor type A for immunohistochemical detection. Interleukin 8 production by cultured cells was measured by enzyme-linked immunosorbent assay. The regulation of interleukin 8 messenger ribonucleic acid expression was assessed by means of the Northern blot analysis after treatment of myometrial cells with interleukin 1alpha and tumor necrosis factor alpha. Myometrial cell proliferation was determined by means of colorimetric assay after cells were treated with interleukin 8 and antihuman interleukin 8 neutralizing antibody. RESULTS: Immunostaining for both interleukin 8 and interleukin 8 receptor type A was stronger in the myometrium adjacent to leiomyoma compared with leiomyoma itself (2-fold, P <.05). Compared with samples from nonusers, samples from patients who had used gonadotropin-releasing hormone agonists revealed a trend for decreased staining for both interleukin 8 and interleukin 8 receptor type A. Interleukin 1alpha and tumor necrosis factor alpha caused a time- and dose-dependent increase in interleukin 8 production by myometrial cells (P <.001). There was a dose-dependent inhibition of cell proliferation with antihuman interleukin 8 antibody to 55% of the control (P <.001). CONCLUSION: Our demonstration of high levels of interleukin 8 and its receptor in myometrium immediately surrounding leiomyoma and the inhibition of cell proliferation when interleukin 8 is blocked by a neutralizing antibody suggest a potential role for interleukin 8 in the growth of myometrial tissue surrounding leiomyomatous tissue. This study could lead to a better understanding of potential involvement of cytokines in leiomyoma growth and in gonadatropin-releasing hormone agonist-induced regression.

Blotting, Northern↗
PubMed2001

The sesquiterpene lactone dehydroleucodine reversibly inhibits Allium cepa L. root growth.

Here, we prove that dehydroleucodine, a sesquiterpene lactone, at low concentrations (25-100 microM) slowed down the Allium cepa L root growth by 22-70% respectively neither affecting cell viability nor cell size. Removal of the drug after 24 h incubation restored the normal growth rate of the roots. Higher concentrations (200 microM) of dehydroleucodine were deleterious for the roots. As cell size did not change, it is most likely that dehydroleucodine affected some event of cell division cycle making it longer. Thus, dehydroleucodine could be a useful tool to slow down cell proliferation.

Cell Size↗
PubMed1999

Prognostic significance of the detection of circulating malignant cells by reverse transcriptase-polymerase chain reaction in long-term clinically disease-free melanoma patients.

The purpose of this study was to assess the prognostic significance of the detection of circulating melanoma cells by reverse transcriptase-PCR in long-term clinically disease-free melanoma patients. Patients with melanoma who were free of clinical relapse for at least 6 months after primary tumor diagnosis were included and prospectively followed. Tyrosinase mRNA in peripheral blood from these patients was assayed by reverse transcriptase-PCR at the time of their inclusion in the study. One hundred six blood samples from 57 melanoma patients were analyzed. The median time between melanoma diagnosis and inclusion in the study was 24 months (range, 7-51 months). The median follow-up time calculated from the time of inclusion in the study was 27 months (range, 11-36 months). Tyrosinase mRNA in blood was detected in 10 (17.5%) of 57 patients: 2 (18%) of 11 stage I patients, 6 (19%) of 33 stage II patients, and 2 (15%) of 13 stage III patients. Actuarial 2-year DFS was 89% for the tyrosinase-negative patients versus 30% for the positive patients (P = 0.003). Actuarial 2-year OS was 97% for the tyrosinase-negative patients versus 72% for the positive patients (P = 0.001). Tyrosinase mRNA could be detected in the blood of a proportion of long-term disease-free melanoma patients, regardless of their initial clinical stage. The presence of late circulating melanoma cells in this selected group of clinically disease-free patients was significantly associated with a subsequent high risk of relapse and death.

Adult↗
PubMed1998

Macrophages, estrogen and the microenvironment of breast cancer.

Estrogen is a major mitogenic stimulus to established breast cancer. Estrogen sources include ovarian, extraglandular sites and breast tissue. Which source primarily maintains benign and breast cancer tissue estrogen concentrations remains unclear. While macrophages may comprise up to 50% of the mass of breast carcinomas, previous studies neglected to study them as possible sources of estrogen. We present evidence that breast macrophages constitute an in situ source of estradiol and that the amount produced is sufficient to mediate cellular proliferation. We utilized immunohistochemistry and RT-PCR to study cell-specific aromatase expression in (i) 29 breast biopsies, (ii) human monocytes/macrophages and (iii) a myeloid cell line (THP-1) capable of differentiating into macrophages. Use of a breast cancer cell line (MCF-7) provided biologic confirmation of the role of aromatization in cell proliferation. We demonstrated considerable amounts of immunoreactive-aromatase (irARO) in breast tissue macrophages and a positive correlation between the proportion of irARO present in macrophages and lesion severity. Using in vitro techniques, we demonstrated that monocytes and THP-1 cells require differentiation into macrophages to produce aromatase in amounts approaching placental levels. The amount of estrogen produced by THP-1 cells stimulated MCF-7 cells to proliferate, an effect blocked by aromatase inhibitors. Estrogen production by macrophages in breast tissue appears sufficient to stimulate the proliferation of adjacent epithelial cells and to autoregulate cytokine production. These findings represent a new dimension of cellular regulation in breast tissue with major biologic implications, amenable to pharmacological manipulation.

Antineoplastic Agents↗
PubMed1998

Laparoscopic treatment of symptomatic cysts of the liver.

BACKGROUND: Reports of successful treatment of liver cysts by the laparoscopic approach prompted the use of this technique in a series of patients. METHODS: Ten patients with symptomatic liver cysts were treated by the laparoscopic deroofing technique. Eight patients had one solitary cyst, one had two cysts and the remaining patient had polycystic disease with a giant cyst. Hydatid disease was excluded serologically and radiologically but albendazole was used before operation in six cases because hydatid disease is endemic in Argentina. RESULTS: There was no surgical morbidity or death. For between 6 months and 3 years all patients were asymptomatic. Computed tomography showed recurrence of a cyst in one patient, who was successfully reoperated on laparoscopically. CONCLUSION: Laparoscopic fenestration of either solitary or multiple liver cysts is the treatment of choice. It produces minimal surgical trauma, shorter hospital stay and avoids the morbidity of laparotomy. Reduced postoperative adhesions allows repeated procedures if the condition recurs.

Adult↗
PubMed1998

Lost stones during laparoscopic cholecystectomy.

BACKGROUND: Gallbladder perforation, with loss of calculi in the abdomen is frequent during laparoscopic cholecystectomy. Recent publications report complications in port sites or in the abdominal cavity. A study of 3686 laparsocopic cholecystectomies performed by 6 surgeons was undertaken. In 627 patients, perforation of the gallbladder occurred and in 254 stones were spilled into the abdominal cavity. In 214 they were retrieved and in 40 left in the abdomen. Twelve patients developed complications. Percutaneous drainage was successful in 2 with serous collections. Two patients with abdominal abscesses were reoperated, stones retrieved and the abdomen drained. One patient developed an intestinal obstruction due to a stone in the ileum. One patient who had a cholecystectomy in another hospital developed a paraumbilical tumor. At reoperation a stone was retrieved. In another six patients, stones were found in port sites. Stones lost into the abdomen should be removed because of their potential morbidity, especially if they are large or if infection is present in the gallbladder at the time of initial surgery. There is no indication for routine conversion to open surgery when stone spillage occurs, although patients should be informed to avoid legal consequence, and to hasten early diagnosis of later complications.

Cholecystectomy, Laparoscopic↗
PubMed1997

Effect of glandular kallikrein on distal nephron HCO3- secretion in rats and on HCO3- secretion in MDCK cells.

Renal kallikrein is localized in the connecting tubule cells and secreted into the tubular fluid at late distal nephron segments. The present experiments were performed to further test the hypothesis that renal kallikrein reduces bicarbonate secretion of cortical collecting duct (CCD). The effect of orthograde injections of pig pancreatic kallikrein (1 or 3 micrograms/ml) into the renal tubular system was investigated. Urine fractions (Fr) were collected after a 2-min stop flow. Changes in the urine fraction with respect to those in free-flow urine samples (Ff) were related to the respective polyfructosan (Inutest) ratio. Renal kallikrein activity (Fr:Ff kallikrein/ Fr:Ff polyfructosan) increased significantly in the first two urine fractions collected after glandular kallikrein administration (kallikrein, 1 microgram/ml, P < 0.05; kallikrein, 3 micrograms/ml, P < 0.01). HCO3- secretion of collecting ducts was significantly reduced dose dependently by orthograde and also reduced by retrograde pig pancreatic kallikrein administration. Release of kinins into the fractions was not affected by the retrograde kallikrein injection, even though the kallikrein activity increased considerably (2.26 +/- 0.2 vs. 1.55 +/- 0.2, P < 0.05). Adequacy of retrograde injections for delivering substances to the CCD was demonstrated by injecting colloidal mercury and detecting the appearance of this mercury in the renal cortex by transmission electron microscopy. The integrity of the renal tissue after a retrograde ureteral injection was confirmed by scanning electron microscopy. These results confirm and extend previous data (M. Marin-Grez and P. Vallés. Renal Physiol. Biochem. 17: 301-306, 1994; and M. Marin-Grez, P. Vallés, and P. Odigie. J. Physiol. 488: 163-170, 1995) showing that renal kallikrein reduces bicarbonate secretion at the CCD, probably by inhibiting HCO3- transported by a mechanism unrelated to its kininogenase activity. Support for this assessment was obtained in experiments testing the effect of kallikrein on the luminal bicarbonate secretion of a subpopulation of Madin-Darby canine kidney cells capable of extruding the anion. Kallikrein inhibited HCO3-/Cl- exchange, and the degree of inhibition was dose dependent. This inhibition occurred in the absence of kininogen in the bathing solution.

Animals↗
PubMed1997

Effects of a skill-based intervention to encourage condom use among high risk heterosexually active adolescents.

OBJECTIVES: In this article we describe the development and testing of three behavioral interventions to reduce the risk of contracting HIV/AIDS and other sexually transmitted diseases among heterosexually active adolescents. METHODS: The interventions include a comic book, a videotape, and a group skill training curriculum that emphasize skill development--for communicating and negotiating condom use with partners, in addition to providing basic information. Participants included 228 youths sampled in juvenile detention and 168 youths sampled from public health STD and other similar clinics. The samples included both young men and women, and were comprised of African American and European American adolescents, ages 14-19. RESULTS: Examination of the relative efficacy of the interventions at three and six months following intervention show very few differences among conditions, despite the fact that the interventions contained most of the elements that previously have been defined as essential for effective interventions. CONCLUSIONS: In the discussion, we consider possible reasons for this outcome and make recommendations for future research.

Adolescent↗
PubMed1997

Quality improvement in the ambulatory surgical setting.

Quality improvement is considered part of "business as usual" in the health care field. Some institutions have progressed further into their quality improvement efforts than others. Nonetheless, there is always the opportunity to learn from the efforts of others and to adopt their methods for use in one's own setting when possible. Included in this article is a case study outlining the use of the FOCUS PDCA methodology for quality improvement. The information identifies ways of introducing and beginning quality improvement efforts in a way that can be translated into other ambulatory health care settings.

Ambulatory Surgical Procedures↗
PubMed1996

Hypertonic saline challenge in an adult epidemiological survey.

Bronchial provocation tests using pharmacological agents such as methacholine or histamine are used in epidemiological studies to identify asthma despite recognition of limitations in specificity, positive predictive value and availability of reagents. Hypertonic saline (4.5%) bronchial challenge (HSBC), although less sensitive than pharmacological challenges, is reportedly highly specific in diagnosing current asthma. Added advantages are that reagents are cheap, stable and recognized by participants. Thus, HSBC may offer benefits over pharmacological tests in epidemiological surveys. This paper reports on the second field survey using the test, a study of 99 adults from the timber industry in Western Australia. The test is described and critically appraised as a practical epidemiological tool for assessing asthma prevalence. At a cutoff point of 20% FEV, fall, HSBC was positive in 8% of subjects, appeared specific for asthma, was safe, well-accepted and easy to use in the field.

Adult↗
PubMed1995

Development of provider networks for specific diseases.

Carve out contracting for specific diseases and specialty services has become extremely common in a very short time. The goal of carve out contracting is simple: to place responsibility for managing care and its cost in the hands of those best suited to provide and manage care. This article provides an overview of carve out contracting for specific diseases. While the article focuses on business and legal issues relating to AIDS/HIV and ESRD, the principles discussed are applicable to numerous diseases.

Community Networks↗
PubMed1994

Phase II study of deoxyspergualin in metastatic breast cancer.

We conducted a phase II trial of the novel immunomodulatory/cytotoxic agent 15-deoxyspergualin in patients with metastatic breast cancer who had failed treatment with front-line chemotherapy. Thirty-eight courses of treatment were administered to fourteen patients enrolled in this trial, 25 at a dose of 1800 mg/m2/d (dose level 0) and 13 at a dose of 2150 mg/m2/d (dose level +1) administered by continuous intravenous infusion for 5 days. Treatment was well tolerated with neuromuscular side-effects (myalgias, paresthesias) and granulocytopenia (nadir granulocyte count of 0.50-0.99 x 10(9)/l) in two and three courses, respectively, as the only grade III toxicities. The neuromuscular toxicity of deoxyspergualin is probably related to the occurrence of hypomagnesemia. No partial or complete responses were observed in this study. One patient achieved a minor response but had progressive disease 65 weeks after enrollment. The response was observed coincident with an increase in T4/T8 ratio in the peripheral blood. The median time to progression for the entire cohort was eight weeks (range, 4-65 weeks). There was no clinical evidence of immunosuppression and no decrease in total peripheral blood lymphocyte counts or helper T-cells was observed. At the doses and schedule employed in this trial, deoxyspergualin does not appear to have significant activity against metastatic breast cancer resistant to front-line chemotherapy. The correlation between hypomagnesemia and neuromuscular toxicity of deoxyspergualin is an intriguing, previously unknown observation and requires further investigation.

Adult↗
PubMed1994

Acute sideroblastic anemia in active systemic lupus erythematosus.

This work describes the development of sideroblastic anemia (SA) during the clinical activity of systemic lupus erythematosus (SLE) in two patients. The cases refer to two women with SLE who developed SA during a relapse of the illness. Both patients fulfilled at least four criteria of the American Association of Rheumatology for SLE. In one patient, the treatment with prednisone was followed by the resolution of the SLE activity and the disappearance of the SA. Several years later there was no evidence of ringed sideroblasts or malignancy in the bone marrow. In the other patient, the clinical activity of the SLE and SA developed during the beginning of a septicemic event which finally led to her death. Our clinical cases allow us to show that the transitory development of SA can occur during a period of clinical activity of SLE and that its association, although infrequent, is due to a common physiopathogenic mechanism.

Acute Disease↗