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Biomedical subjects

L Flores

Publications and source records attributed to L Flores.

At least 19 recordsLinked to original sources
PubMed2001

Analysis of nonpenetrating clips versus sutures for arterial venous graft anastomosis.

The use of nonpenetrating clips (NPC) for vascular anastomosis is quickly becoming accepted. Studies attest to decreased anastomotic time, comparable patency rates, and decreased blood loss. Few human studies on the use of NPC have been done to date. The purpose of this study was to evaluate primary patency rates, operative time, and complications associated with NPC compared to those with standard sutures for arterial venous graft (AVG). We retrospectively reviewed the clinical course of 82 patients with a mean age of 45 years (range, 22 to 87) from February 1996 to July 1999. All patients underwent upper extremity AVG construction. The procedures were performed at a single institution, by a single, well-experienced surgeon who has extensive experience with NPC. Primary patency rates, operative time, and complications were analyzed. Overall thrombotic incidence of AVG when NPC were used (27/48, 56%) was similar to that of sutures (17/34, 50%). Thrombotic incidence within the first year was similar as well (23/48, 48% and 13/34, 38%). The mean time to primary thrombosis was similar in both groups (6.9 and 6.8 months). The operative time required to construct an AVG with NPC (83 min) was significantly less than that with sutures (96 min) (p = 0.015). There was no significant difference in incidence of graft infection or pseudoaneurysm formation. NPC for AVG reduced operative time and resulted in primary patency and complication rates similar to those associated with use of sutures. The mean time to primary thrombosis was similar for both groups. Our findings suggest an intimal hyperplastic response of a similar nature resulting in thrombosis of both NPC and sutured AVGs.

Adult↗
PubMed2001

Effect of losartan on TGF-beta1 and urinary albumin excretion in patients with type 2 diabetes mellitus and microalbuminuria.

BACKGROUND: The aim of the present study was to determine the effect of losartan on transforming growth factor-beta1 (TGF-beta1) plasma levels and urinary albumin excretion (UAE) in patients with type 2 diabetes mellitus, mild hypertension and microalbuminuria. METHODS: Fourteen patients (eight males, aged 55+/-6 years) with type 2 diabetes mellitus, mild arterial hypertension and microalbuminuria, participating in an open, uncontrolled, pilot study were included. Patients were treated for 8 weeks with losartan. TGF-beta1 plasma levels, UAE and 24-h blood pressure monitoring were determined at baseline and at 4 and 8 weeks. RESULTS: At 4 and 8 weeks of treatment, a reduction was observed in TGF-beta1 plasma levels (5.5+/-4.5 vs 2.0+/-0.6 and 2.6+/-1.0 ng/ml, P<0.005), UAE (96+/-65 vs 59+/-59 and 64+/-47 microg/min, P<0.01), 24-h systolic blood pressure (136+/-9 vs 129+/-9 and 130+/-10 mmHg, P<0.01) and 24-h diastolic blood pressure (77+/-9 vs 74+/-8 and 74+/-7 mmHg, P<0.03). Stratifying the patients by baseline TGF-beta1, seven had TGF-beta1 plasma values higher than normal controls. At 4 and 8 weeks, they showed a marked reduction in TGF-beta1 values (9.0+/-3.9 to 2.1+/-0.7 and 2.5+/-0.7 ng/ml, P<0.01) and UAE (106+/-83 to 49+/-42 and 38+/-26 microg/min, P<0.05), with good correlation between the percentage reduction of both parameters (r=0.83, P<0.01). The remaining seven patients, with normal baseline TGF-beta1 plasma levels, showed no change in TGF-beta1 plasma levels and UAE after treatment. CONCLUSION: Treatment with losartan decreases TGF-beta1 plasma values and UAE in type 2 diabetes mellitus patients with high baseline TGF-beta1 levels, suggesting that TGF-beta1 may be a marker to detect patients who may particularly benefit from renin-angiotensin system blockade.

Albuminuria↗
PubMed2001

Cyclospora cayetanensis in three populations at risk in Guatemala.

In 1996 and 1997, outbreaks of Cyclospora cayetanensis in North America were linked to Guatemalan raspberries. From April 1999 to April 2000, we undertook a survey for C. cayetanensis in raspberry farm workers, malnourished children, and human immunodeficiency virus and AIDS patients in Guatemala. Stool samples were analyzed using ethylacetate-formalin concentration, wet preparation, modified acid-fast staining method, and epifluorescence. Oocysts were found in 1.5% of the subjects, none of whom were raspberry farm workers.

AIDS-Related Opportunistic Infections↗
PubMed2000

Metallothionein isoform 1 and 2 gene expression in the human prostate: downregulation of MT-1X in advanced prostate cancer.

BACKGROUND: Studies have shown an association of metallothionein (MT) overexpression with tumor type and grade. However, a family of genes underlies the expression of these proteins. The goals of this study were to define the expression of MT genes and protein in normal human prostate and to provide evidence that the expression of the MT isoforms is altered in prostate cancer. METHODS: Immunohistochemistry was used to localize MT protein, reverse transcription-polymerase chain reaction (RT-PCR) to determine the MT isoform-specific mRNAs, and immunoblot analysis to determine MT protein levels. RESULTS: The localization of MT in the prostate was further defined using the E9 antibody. Using normal prostate tissue dissected from glands removed for prostate cancer, it was demonstrated that MT protein expression in the normal prostate is supported by mRNA from the MT-1A, MT-1E, MT-1X, and MT-2A genes. No expression of the MT-1X gene was demonstrated in cases of advanced prostate cancer. The expression of MT-1 and MT-2 isoform-specific mRNA varied among three commonly utilized prostate cancer cell lines. CONCLUSIONS: MT protein in the normal human prostate is supported by transcription of mRNA from the MT-1A, MT-1E, MT-1X, and MT-2A genes. Expression of MT-1X mRNA is downregulated in advanced prostate cancer. Variable expression of MT mRNA in prostate cell lines provides evidence that MT gene expression may be altered among individual prostate cancers.

Cell Line↗
PubMed2000

White coat hypertension in type 1 diabetic patients without nephropathy.

The aim of our study was to determine the prevalence of white coat hypertension (WCH) in type 1 diabetic patients. Therefore, ambulatory blood pressure monitoring (ABPM) and 24-h urinary albumin excretion (UAE) were determined in 47 patients with type 1 diabetes mellitus (27 with new diagnosis of hypertension by office blood pressure (BP) measurement and 20 with normotension). WCH was diagnosed in 20 patients (74%). Patients with WCH presented higher values of systolic and diastolic BP and UAE than normotensive patients. The results indicate that in type 1 diabetes mellitus WCH is very frequent. Thus, WCH may represent a potential risk for the development of diabetic complications, mainly diabetic nephropathy.

Adult↗
PubMed1999

Functional characterization of transcriptional regulatory elements in the upstream region of the yeast GLK1 gene.

The glucokinase gene GLK1 of the yeast Saccharomyces cerevisiae is transcriptionally regulated in response to the carbon source of the growth medium. Northern-blot analysis shows that the GLK1 gene is expressed at a basal level in the presence of glucose, de-repressed more than 6-fold under conditions of sugar limitation and more than 25-fold under conditions of ethanol induction. lacZ fusions of the GLK1 gene promoter were constructed and a deletion analysis was performed in order to identify the cis-acting regulatory elements of the promoter that controls GLK1 gene expression. First, the expression seemed to be mediated mainly by one GCR1 and three stress-responsive element (STRE) activating elements. Secondly, an ethanol repression autoregulation (ERA)/twelve-fold TA repeat (TAB) repressor element was identified within the promoter region of the GLK1 gene. A specific and differential protein binding to the STRE was observed with extracts from de-repressed and repressed cells. No differential binding to the GCR1 or ERA/TAB elements was observed with extracts from de-repressed and repressed cells, but, in both cases, the binding was competed for by an excess of the unlabelled GLK1(GCR1) and GLK1(ERA) sequence. The transcription factors Msn2 and Msn4, which bind to the GLK1 upstream region through the STRE, contribute to inductive activation. The transcription factor Gcr1, which binds through the GCR1 element, contributes to constitutive activation. In order to achieve the severe glucose repression of GLK1, constitutive repressor factors acting through the ERA/TAB element must counteract constitutive activation generated by Gcr1 binding to the GCR1 element. Full expression of the GLK1 gene is produced by inductive activation of three STRE when Msn2 and Msn4 proteins are translocated to the nucleus by covalent modification. The combinatorial effect of the entire region leads to the regulated transcription of GLK1, i.e., silent in media with glucose and other preferred carbon sources, such as fructose or mannose, and increased levels of expression upon glucose depletion.

Base Sequence↗
PubMed1999

The usefulness of Tc-99m MIBI for evaluating brain tumors: comparative study with Tl-201 and relation with P-glycoprotein

PURPOSE: This study was undertaken to determine the usefulness of Tc-99m methoxyisobutylisonitrile (MIBI) in brain tumors compared with TI-201 imaging. The authors evaluated the correlation between MIBI uptake and the presence of P-glycoprotein, and also the relation between MIBI uptake in response to combined radiotherapy and chemotherapy in glioblastoma. MATERIALS AND METHODS: Thirty-four brain tumors composed of 15 glioblastoma multiforme (GBM), 5 anaplastic astrocytomas, 5 low-grade astrocytomas, and 9 metastases were evaluated. Early and delayed images were obtained for MIBI and Tl-201 scintigraphy. P-glycoprotein status in all GBM, 2 anaplastic astrocytomas, 2 low-grade astrocytomas, and 2 metastases were evaluated immunohistochemically. Patients with GBM were divided into an effective and a noneffective group according to the change in tumor size. MIBI uptake indices were compared for these two groups. RESULTS: Both radiopharmaceuticals accumulated in all GBM and anaplastic astrocytomas. In low-grade astrocytomas, only one case showed tracer uptake. In metastasis, two cases showed high uptake on early images and marked washout on delayed images. Uptake ratio values (early uptake ratio and delayed uptake ratio) in all tumors were significantly higher in MIBI than in Tl-201. Immunohistochemical studies showed that the metastases were positive for P-glycoprotein but the GBM were not. In low-grade astrocytomas, a few cells were positively stained. In relation to the therapeutic outcome of GBM, both the early and delayed uptake ratios of MIBI were significantly greater in the noneffective group. CONCLUSIONS: Although diagnostic ability was comparable in MIBI and Tl-201, the imaging quality was better in MIBI. Both radiopharmaceuticals are useful in differentiating low-grade glioma from high-grade glioma. MIBI delayed imaging could also reflect the presence of P-glycoprotein. Intense MIBI uptake was also predictive of a poor clinical outcome in GBM.

Journal Article↗
PubMed1999

The role of IGF binding protein-3 as a parameter of activity in acromegalic patients.

OBJECTIVE: The production of insulin-like growth factor binding protein-3 (IGFBP-3), the main IGF-I binding protein, is regulated by GH, and its serum levels are increased in acromegaly. We investigated its potential value as a parameter of acromegaly activity or remission in comparison with IGF-I, taking GH suppression below 2 microg/l after glucose load as the normal standard. METHODS: Data from 40 acromegalic patients (12 males and 28 females, aged 28 to 79 years) were obtained retrospectively from stored samples. From these, 145 pairs of IGF-I/IGFBP-3 values were collected; in 67 of them, simultaneous measurement of GH after glucose loading allowed their classification as active or inactive acromegaly. Relationships between IGF-I, IGFBP-3 and GH after glucose load were assessed, as well as differences between IGF-I and IGFBP-3 levels in active and inactive acromegaly. RESULTS: Significant positive correlation between IGF-I and IGFBP-3 in 145 samples was observed (r=0.49, P<0. 0001). As for the 67 samples in which activity or remission could be defined in terms of GH after glucose load, 50 were active and 17 inactive. Both IGF-I and IGFBP-3 significantly correlated with minimum GH (r=0.53, P<0.0001 and r=0.41, P<0.001 respectively). For both parameters, significant differences of means between active and inactive cases were observed (623+/-296 vs 300+/-108 ng/ml, P<0.0001 for IGF-I, and 4.1+/-1.3 vs 3.2+/-0.9 microg/ml, P<0.006 for IGFBP-3). Yet, when comparing in individual cases their classification as active or inactive with the finding of normal or increased IGF-I and IGFBP-3, among active cases 16% appeared as normal according to IGF-I, and 50% appeared as normal in terms of IGFBP-3. Among inactive cases, 23.5% appeared as active according to IGF-I, while 17.5% appeared as active in terms of IGFBP-3. CONCLUSION: Even though IGFBP-3 reflects GH secretion, it offers no advantage over IGF-I in the assessment of acromegaly, and it may underestimate disease activity in acromegalic patients.

Acromegaly↗
PubMed1999

Usefulness of ambulatory blood pressure monitoring in pregnant women with type 1 diabetes.

OBJECTIVE: Pregnancy in type 1 diabetes is associated with an increased risk of developing pregnancy-induced hypertension (PIH). Ambulatory blood pressure monitoring (ABPM) has been used to screen for preeclampsia in nondiabetic pregnancy. To date, there are no data regarding ABPM during pregnancy in normotensive type 1 diabetic women. This study sought to establish blood pressure (BP) profiles for pregnant type 1 diabetic women using ABPM and determine whether the BP pattern can define a population at risk for developing PIH. RESEARCH DESIGN AND METHODS: ABPM was carried out for one 24-h period during each trimester--in the first trimester between weeks 7 and 12, in the second trimester between weeks 20 and 24, and in the third trimester between weeks 30 and 34--in 22 normotensive pregnant type 1 diabetic and 10 pregnant nondiabetic women. RESULTS: The incidence of PIH was fourfold greater in type 1 diabetic women than in control subjects. Diabetic women showed higher daily diastolic BP in the third trimester compared with nondiabetic pregnant women. Diabetic women who developed PIH in the third trimester showed significantly higher BP profiles throughout gestation than those who remained normotensive. Receiver operator characteristics curves for nighttime systolic BP showed the best predictive capacity for PIH, with a cutoff > 105 mmHg (85% sensitivity and 92% specificity). CONCLUSIONS: Our study confirms the early increase of BP in patients who will develop PIH and suggests that nighttime systolic BP >105 mmHg in the second trimester is a useful predictor of PIH. ABPM may be useful in screening for PIH in pregnant diabetic women.

Adolescent↗
PubMed1999

Gelatinase activity of matrix metalloproteinases in the cerebrospinal fluid of various patient populations.

We have studied the enzymatic gelatinolytic activity of matrix metalloproteinases (MMPs) present in cerebrospinal fluid (CSF) of samples obtained from 67 individuals, twenty-one nonneurological patients (considered controls) and 46 subjects with various neurological disorders e.g., vascular lesions, demyelination, inflammatory, degenerative and prion diseases. Biochemical characterization of MMPs, a family of neutral proteolytic enzymes involved in extracellular matrix modeling, included determination of substrate specificity and Ca+2 dependency, as well as the effects of protease inactivators, carboxylic and His (histidine) residue modifiers, and antibiotics. Whereas all CSF samples expressed MMP-2 (gelatinase A) activity, it corresponded in most cases (normal and pathological samples) to its latent form (proenzyme; pMMP-2). In general, inflammatory neurological diseases (especially meningitis and neurocisticercosis) were associated with the presence of a second enzyme, MMP-9 (or gelatinase B). Whereas MMP-9 was found in the CSF of every tropical spastic paraparesis patient studied, its presence in samples from individuals with vascular lesions was uncommon. Patients blood-brain barrier damage was ascertained by determining total CSF protein content using both, the conventional polyacrylamide gel electrophoresis procedure under denaturing conditions and capillary zone electrophoresis.

Enzyme Activation↗
PubMed1998

Insulin therapy in type 2 diabetic patients: effects on arterial blood pressure and endothelin-1 plasma levels.

OBJECTIVE: To evaluate the possible effect of short- and long-term insulin treatment on arterial blood pressure (BP) and endothelin-1 (ET-1) plasma levels in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Seven type 2 diabetic patients with secondary failure to oral hypoglycemic drugs (SFOH) were studied. Twenty-four-hour arterial BP monitorization (Spacelabs 90207) was performed before initiation of insulin treatment (time 0), 6 days after (time 1) and 1 year later (time 2). Moreover, ET-1 plasma levels were measured. RESULTS: Insulin treatment did not produce any variation in systolic (124.3 +/- 11.6; 120.7 +/- 7.9; 127.0 +/- 13.4 mmHg) and diastolic (72.8 +/- 5.9; 71.5 +/- 3.4; 71.8 +/- 5.2 mmHg) 24-h BP monitorization at times 0, 1 and 2, respectively. The systolic and diastolic day/night differences did not change in the three times studied. Neither were significant differences observed in ET-1 plasma levels. CONCLUSIONS: In patients with SFOH, insulin treatment did not induce any short- or long-term increase in BP or any variation in plasma ET-1 levels.

Aged↗
PubMed1998

Simultaneous intestinal leishmaniasis and mycobacterial involvement in a patient with acquired immune deficiency syndrome.

Gastrointestinal involvement is reported in approximately 50% to 93% of patients with human immunodeficiency virus. It is frequently the result of coinfection with several microorganisms. Selective Leishmania intestinal involvement presents with atypical symptoms for visceral leishmaniasis, and may appear as a relapse or as the first manifestation of the disease. The authors present a patient with acquired immune deficiency syndrome who has a history of treated leishmaniasis and gastrointestinal infection by showed Mycobacterium avium intracellulare (MAI). After the new onset of abdominal pain, an intestinal biopsy showed the presence of both MAI and Leishmania in duodenum. Intestinal infection by Leishmania must be included in the differential diagnosis in patients with a previous history of leishmaniasis or travel to an endemic area.

AIDS-Related Opportunistic Infections↗
PubMed1997

Objectification of functional improvement after nonoperative care.

STUDY DESIGN: In this article, the authors review the three broad categories of measures that have been used to objectify functional improvement after nonoperative care of painful spinal disorder patients-physical, psychological, and socioeconomic. For each of the three categories, the major measures used are discussed, as well as research relating to the efficacy of the measures. OBJECTIVE: To point out the many differences that still exist among research studies regarding which functional outcome measures to use and when to use them. SUMMARY OF BACKGROUND DATA: During the past few decades, it has been made abundantly clear that painful spinal disorders, particularly when associated with work disability and/or financial benefits, result from a complex interaction of medical, psychological, and social factors. This has resulted in frequent confusion regarding what constitutes the primary roots of the disabling process. Currently, a more comprehensive biopsychosocial perspective of chronic pain and disability has emerged that has significant implications for diagnostic and treatment philosophies of practitioners. METHODS: Identifying the measures frequently used to address the important biopsychosocial factors, and evaluating their relative benefits and drawbacks. RESULTS AND CONCLUSIONS: It is demonstrated that there has been an overall trend in recent years toward using more objective, quantifiable instruments, encompassing the physical, psychological, and socioeconomic parameters of outcomes research in painful spinal disorders. These changes will certainly improve the ability of researchers to tease out which factors tap more directly into such tissue as physical impairment, as well as create greater uniformity of measures that will permit direct comparisons between studies.

Activities of Daily Living↗
PubMed1997

The Genome Sequence DataBase version 1.0 (GSDB): from low pass sequences to complete genomes.

The Genome Sequence DataBase (GSDB) has completed its conversion to an improved relational database. The new database, GSDB 1.0, is fully operational and publicly available. Data contributions, including both original sequence submissions and community annotation, are being accomplished through the use of a graphical client-server interface tool, the GSDB Annotator, and via GIO (GSDB Input/Output) files. Data retrieval services are being provided through a new Web Query Tool and direct SQL. All methods of data contribution and data retrieval fully support the new data types that have been incorporated into GSDB, including discontiguous sequences, multiple sequence alignments, and community annotation.

Animals↗
PubMed1997

Localization and postoperative follow-up of a bronchial carcinoid tumor causing Cushing's syndrome by 111In-DTPA labelled octreotide scintigraphy.

Bronchial carcinoid tumor is the most frequent occult source of ectopic ACTH-dependent Cushing's syndrome, but its initial localization may be very difficult, as well as its postoperative follow-up. We here present the case of a 21-year-old man with Cushing's syndrome and biochemical findings suggesting an ectopic source of ACTH (lack of inhibition of cortisol after overnight 8-mg dexamethasone suppression test, and lack of response to h-CRH challenge). Chest CT-scan showed a node adjacent to the left lung hilium whose nature was confirmed by uptake of 111Indium-DTPA labelled octreotide scintigraphy. Surgical resection of the tumor consisted in an upper lobectomy of the left lung. Microscopic examination identified a typical carcinoid tumor. After surgery pituitary-adrenal function normalized and a second scintigraphy offered additional data on the absence of tumor remnants.

Adrenocorticotropic Hormone↗
PubMed1996

Susceptibility-weighted MR for evaluation of vasodilatory capacity with acetazolamide challenge.

PURPOSE: To investigate cerebral vasodilatory capacity by acetazolamide challenge in healthy subjects and in patients with chronic occlusive cerebrovascular disease by using susceptibility-weighted gradient-echo MR imaging. METHODS: Eight patients with chronic occlusive cerebrovascular disease and four healthy volunteers were studied with susceptibility-weighted MR imaging before and after intravenous administration of 1000 mg of acetazolamide. Signal intensities were measured as a function of time in several regions of interest defined on anatomic images. In all patients with chronic occlusive cerebrovascular disease, acetazolamide challenge and resting regional cerebral blood flow were also evaluated with single-photon emission CT (SPECT). RESULTS: In healthy volunteers, signal intensities began to increase 3 to 4 minutes after acetazolamide administration, with a continuous increase during the subsequent 10 minutes. The effect lasted for approximately 45 minutes after administration. In patients with chronic occlusive cerebrovascular disease, signal changes on susceptibility-weighted MR images of occluded areas with normal vasodilatory capacity on SPECT images did not differ from signal changes of nonocclusive areas. In those patients with changes that reflected diminished vasodilatory capacity, the MR images showed a lower percentage of signal changes after acetazolamide administration than those in normally perfused areas. CONCLUSION: Susceptibility-weighted MR imaging offers an alternative method for estimating vasodilatory capacity.

Acetazolamide↗