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J M Lopez

Publications and source records attributed to J M Lopez.

At least 37 records · Page 2Linked to original sources
PubMed1996

Sterol regulation of acetyl coenzyme A carboxylase: a mechanism for coordinate control of cellular lipid.

Transcription from the housekeeping promoter for the acetyl coenzyme A carboxylase (ACC) gene, which encodes the rate-controlling enzyme of fatty acid biosynthesis, is shown to be regulated by cellular sterol levels through novel binding sites for the sterol-sensitive sterol regulatory element binding protein (SREBP)-1 transcription factor. The position of the SREBP sites relative to those for the ubiquitous auxiliary transcription factor Sp1 is reminiscent of that previously described for the sterol-regulated low density lipoprotein receptor promoter. The experiments provide molecular evidence that the metabolism of fatty acids and cholesterol, two different classes of essential cellular lipids, are coordinately regulated by cellular lipid levels.

Acetyl-CoA Carboxylase↗
PubMed1996

Early placement of prophylactic vena caval filters in injured patients at high risk for pulmonary embolism.

OBJECTIVE: Pulmonary embolism (PE) is a major problem in patients with multiple injuries. We present our experience with early placement of prophylactic vena caval filters (VCFs). DESIGN: Prospective study group with historical control. MATERIALS AND METHODS: From March 1993 to December 1993, VCFs were placed in 40 consecutive patients with three or more risk factors for PE and had demographic, physiologic, venous thromboembolic prophylaxis, and outcome data collected prospectively (VCF group). They were compared to 80 injured patients admitted between November 1991 and February 1993 who survived > 48 hours and who were matched with the VCF group for mechanism of injury and risk factors for PE (NO VCF group). MEASUREMENTS AND MAIN RESULTS: VCF placement affected a significant reduction in the incidence of PE (2.5% vs. 17%) and a clinical reduction in PE-related mortality. Embolic trapping was suggested by a 10% incidence of documented vena caval thrombi and although two patients developed significant venous stasis disease, no other VCF-related morbidity was noted. CONCLUSIONS: In spite of long-term morbidity, early prophylactic VCF placement is safe and should be considered in the prophylaxis of PE in the high-risk injured patients. This intervention may be effective in eliminating PE as a major cause of posttrauma morbidity and mortality.

Adult↗
PubMed1996

Serum amino-terminal propeptide of type III procollagen levels in chronic pancreatitis.

The severity of pancreatic fibrosis, a characteristic feature of patients with chronic pancreatitis (CP), can be assessed only by direct histologic analysis of pancreatic tissue. Since serum levels of the amino-terminal type III procollagen propeptide (PIIIP) can reflect the degree of fibrogenic activity in several diseases associated with fibrosis, the current study was aimed at investigating whether PIIIP are increased in chronic pancreatitis, the relationship between PIIIP and pancreatic fibrogenic activity, and the influence of pancreatectomy, pancreatic exocrine function, and duration of disease on PIIIP levels. Serum PIIIP was measured in 18 patients with CP (15 without liver disease and three with cholestasis) and in 21 healthy controls. The effect of pancreatectomy on PIIIP was evaluated in seven patients, in whom PIIIP was measured immediately before and 2 months after surgery. Prolylhydroxylase (PHase) activity as an index of pancreatic fibrogenesis was evaluated in pancreatic tissue from 11 patients who had undergone subtotal pancreatectomy and from 11 organ donors. The bentiromide (BT)-PABA test as an index of exocrine pancreatic function was measured in all patients. PIIIP was significantly higher in patients who had or had not undergone pancreatectomy (17.3 +/- 4.0 and 25 +/- 11.4 ng/ml, respectively) than in controls (12.3 +/- 3.1 ng/ml) (p < 0.001). PIIIP decreased significantly after pancreatectomy (before, 32.0 +/- 9.3 ng/ml; after, 18.4 +/- 4.8 ng/ml; p = 0.005). PHase was significantly higher in patients (773 +/- 250 cpm/mg protein) than in controls (405 +/- 121 cpm/mg protein) (p < 0.001). PIIIP was correlated with pancreatic PHase (r = 0.7, p = 0.001) but not with BT-PABA or with the duration of the disease. In conclusion, serum PIIIP levels are increased in patients with CP and reflect the severity of pancreatic fibrogenic activity. No relationship between the serum PIIIP levels and the pancreatic exocrine function and duration of disease was found.

Adult↗
PubMed1996

New insights into the cytodynamics of the hamster Harderian gland as provided by the bromodeoxyuridine-labelling method.

The fourth week of postnatal life is a critical point in the development of the hamster Harderian gland. During this week, cells with large lipid vacuoles (type-II cells) appear in the male gland, marking a morphological sex difference that is notorious in adult animals. The origin and fate of type-II cells are controversial. To gain insight into the mechanisms by which type-II cells become a major cell type in the gland of adult male hamsters, bromodeoxyuridine (BrdU) labelling was used to assess the proliferative activity of both types of glandular cells in 28-day-old animals. To search for possible sex differences in the proliferative activity of this gland, female animals of the same age as the males were also studied. No difference was found in the overall labelling index (BrdU-labelled cells/100 cells) between males (1.8 +/- 0.1%) and females (1.5 +/- 0.1%). In the gland of the males, the specific labelling index of type-II cells (3.4 +/- 0.4%) was significantly higher than that of type-I cells (0.9 +/- 0.2%). Interestingly, the proportion of type-II cells present in the male glands at this age (36.6%) was significantly lower than that of type-I cells. Our results strongly suggest that the proliferation of type-II cells, rather than a continuous differentiation of these cells from preexisting type-I cells, is a major event in the achievement of the mature form of this gland. The results reported here counsel a reappraisal of current theories about the cytodynamics of the hamster Harderian gland.

Animals↗
PubMed1995

Sterol regulation of fatty acid synthase promoter. Coordinate feedback regulation of two major lipid pathways.

The gene encoding fatty acid synthase, the essential multi-functional enzyme of fatty acid biosynthesis, is shown to be regulated by cellular sterol levels similar to genes that encode important proteins of cholesterol metabolism. We show that expression of the endogenous FAS gene is repressed when regulatory sterols are included in the culture medium of HepG2 cells and that the FAS promoter is subject to similar regulation when fused to the luciferase reporter gene. Mutational studies demonstrate that sterol regulation is mediated by binding sites for the sterol regulatory element-binding protein (SREBP) and transcription factor Sp1, making it mechanistically similar to sterol regulation of the low density lipoprotein receptor gene. It is also demonstrated that SREBP and Sp1 synergistically activate the FAS promoter in Drosophila tissue culture cells, which lack endogenous Sp1. These experiments provide key molecular evidence that directly links the metabolism of fatty acids and cholesterol together.

Animals↗
PubMed1995

Bioactive GH-like immunoglobulins G in active acromegaly: response to long-term treatment with bromocriptine.

In acromegaly, certain forms of circulating immunoreactive hGH are not true GH but IgGs which possess GH biological activity (bioactive GH-like IgGs). In this study, we tested the effect of bromocriptine on circulating bioactive GH-like IgGs in an acromegalic woman. Increasing doses of oral bromocriptine (2.5, 5.0 and 7.5 mg/day) were administered (for 2, 8 and 6 months respectively). TRH tests were performed before treatment and at the end of treatment with each dose. The patient was without detectable pituitary or extra-pituitary tumour by magnetic resonance imaging. Her serum contained bioactive GH-like IgGs equivalent to 240 mU/l of hGH and elevated insulin-like growth factor I (IGF-I; 9500 U/l). Basal hGH was 12.8 mU/l and increased to 220 mU/l 15 min after TRH (200 micrograms, i.v.). In addition, in the basal samples of each test we measured total IgGs (radial immunodiffusion), bioactive GH-like IgGs (isolated by Sephadex and protein A affinity chromatography and assayed using the Nb2 cell assay) and IGF-I(RIA). Bromocriptine treatment gradually reduced serum levels of bioactive GH-like IgGs and IGF-I, with significant falls observed first at 10 months of treatment. Bioactive GH-like IgGs were 240, 240, 36.0 and < 0.124 mU/l and IGF-I levels were 9500, 8700, 4000 and 3100 U/l at 0, 2, 10 and 16 months of treatment, respectively. In contrast, IR-hGH response to TRH decreased after 2 months of treatment to 89 mU/l and to 49.2 mU/l at the end of the study while basal IR-hGH remained between 13 and 8.4 mU/l. Basal PRL fell to almost undetectable levels. Bromocriptine treatment decreased the GH response to TRH and the serum concentration of bioactive GH-like IgGs and IGF-I. The striking similarity between the pattern of decrease of serum bioactive GH-like IgGs and IGF-I supports the presence of an immuno component in our patient's acromegaly.

Acromegaly↗
PubMed1994

The Drosophila fs(1)Ya protein, which is needed for the first mitotic division, is in the nuclear lamina and in the envelopes of cleavage nuclei, pronuclei, and nonmitotic nuclei.

The Drosophila melanogaster fs (1) Ya gene encodes a nuclear envelope protein needed to initiate embryonic cleavage divisions. In cleavage stage embryos the fs (1) Ya gene product is localized to the nuclear envelope in a cell cycle dependent manner. We show here that fs(1)Ya protein is also present in polar bodies of early cleavage stage embryos as well as in endoreplicating yolk nuclei. This observation suggests that the fs(1)Ya protein is necessary but not solely responsible for embryonic mitosis. Furthermore, cell cycle stage dependent nuclear localization is also seen for ectopically produced fs(1)Ya protein in tissue culture cells, neuroblasts, and male accessory glands, which are free of maternal products. We therefore conclude that cell cycle dependent nuclear localization does not require any exclusively maternal products. Finally, our immunoelectron microscopy shows that the fs(1)Ya protein distribution parallels that of lamin, indicating that it is a nuclear lamina protein.

Animals↗
PubMed1993

Primary liver cancer in genetic hemochromatosis: a clinical, pathological, and pathogenetic study of 54 cases.

BACKGROUND: Although liver cancer arises frequently in the course of genetic hemochromatosis (GH), it has not been previously studied in a large series of patients with well-defined GH. METHODS: The bioclinical and pathological data from 1 cholangiocarcinoma and 53 hepatocellular carcinomas (HCCs) complicating GH in 32 untreated and 22 de-ironed patients are reported. RESULTS: This study (1) adds three new well-documented cases of HCC in noncirrhotic but only fibrotic hemochromatotic liver, (2) shows the high prevalence (83%) of proliferative and often dysplastic (70%) iron-free foci in the nontumorous liver of untreated patients, and (3) emphasizes the significant increase of cirrhosis (81% vs. 28%) and of associated noniron-related risk factors, mainly chronic alcoholism (48% vs. 25%) and tobacco smoking (50% vs. 18%) in patients with HCC compared with matched hemochromatotic patients without HCC. CONCLUSIONS: These data (1) suggest that iron-free foci may be markers of an early stage of HCC in GH and (2) supply the basis for defining a cost-effective policy for the screening of HCC in GH patients.

Female↗
PubMed1993

Effect of dietary coconut oil on lipoprotein composition of young chick (Gallus domesticus).

1. The composition of HDL, the major lipoprotein fraction from chick serum, drastically changed after 2 weeks of coconut oil feeding. Total cholesterol and triacylglycerols significantly increased following dietary 10 or 20% coconut oil supplementation. 2. Changes in LDL composition were less profound, cholesterol being the only component that increased by coconut oil supplementation (10 or 20%). 3. IDL proteins were the only components that increased following the same dietary treatment (20%). 4. VLDL cholesterol and proteins also increased after 1-2 weeks of 20% coconut oil supplementation to the diet. 5. Of total lipoproteins, the cholesterol content strongly increased after dietary treatment, while triacylglycerols did not change significantly.

Animals↗
PubMed1992

Surveillance in evacuation camps after the eruption of Mt. Pinatubo, Philippines.

To obtain accurate, timely data on the health status of persons in evacuation camps after the eruption of the Mt. Pinatubo volcano, the Philippine Department of Health (DOH) conducted a survey of the health needs of the evacuees and established disease surveillance in each camp. Surveys of the camps revealed that sources of potable water, sanitary means of waste disposal, and shelters were inadequate. Disease surveillance showed that measles, acute respiratory infections, and diarrhea were the most important problems. Surveillance detected outbreaks of measles and an outbreak of vomiting and diarrhea in the camps. Deaths, primarily caused by measles (31%), diarrhea (29%), and respiratory infections (22%), totaled 349 in the first 12 weeks. Death rates peaked in the seventh week, when a death rate of 26/10,000 occurred among the Aetas, a tribe evacuated from the slopes of the volcano. The surveys guided the DOH in allocating supplies and medicine, while disease surveillance enabled disaster managers to monitor the effectiveness of health programs, identify high-risk groups, and respond appropriately to the situation.

Diarrhea↗
PubMed1992

Comparison of a new commercial enzyme immunoassay for rapid detection of respiratory syncytial virus.

Two rapid methods for detection of respiratory syncytial virus in respiratory specimens were compared: direct immunofluorescence assay (DFA) with monoclonal antibody and an enzyme immunoassay (EIA) (Test-Pack RSV). Ninety-five nasopharyngeal washings and aspirates from 51 children were examined; the patients were hospitalized during a winter outbreak of RSV infection in the first trimester of 1990. A total of 41.0% and 56.8% of these samples were positive by EIA and DFA respectively. Considering only the 51 specimens collected at the onset of illness, EIA detected 72.5% positive samples and DFA detected 78.4%. In comparison with DFA, EIA was 92.5% sensitive and 100% specific for the acute phase of illness. When all the samples were taken into account, specificity was maintained but sensitivity fell to 72.2%. The results show that both methods are useful during the acute phase of the illness, when the viral load is important. However, later on in the course of the infection DFA appears to be more sensitive than EIA.

Female↗
PubMed1992

Growth hormone (GH) receptor antibodies with GH-like activity occur spontaneously in acromegaly.

Previous studies in our laboratory have identified a portion of big-big GH as actually being anti-GH receptor immunoglobulins. We now report the isolation of two types of anti-GH receptor antibodies from the serum of active acromegalic patients. One of them (patient A) interferes with the human GH RIA, thus overestimating the real plasma GH values. The other type of immunoglobulin G (IgG; patient B) was detected in an acromegalic patient with almost normal immunoreactive GH level. The main aim of the present study was to explore whether these anti-GH receptor IgGs possess GH-like biological activity. The IgGs of both patients were isolated by chromatography on Sephadex G-100 and then on protein-A-Sepharose. In the bioassay, cultured Nb2 lymphoma cells were incubated with hGH standards and serial dilutions of the purified IgGs, and cell proliferation was used as a measure of biological activity. The IgGs of both patients showed GH-like bioactivities, which, when calculated as equivalents of human GH, correspond to approximately 260 and 120 micrograms/L, respectively. The results suggest that biologically active anti-GH receptor antibodies may contribute in the pathology of some cases of acromegaly.

Acromegaly↗
PubMed1991

Decentration of intraocular lenses implanted after intercapsular cataract extraction (envelope technique).

Pseudophakos decentration produces symptoms such as glare, halos, and other visual aberrations. We have reviewed 161 eyes of patients who had an intercapsular cataract extraction with intraocular lens (IOL) implantation with a follow-up of at least six months. Mean decentration was 0.54 mm. It was 0.46 mm for the lenses implanted symmetrically in the bag, 0.65 mm for those implanted in the sulcus, and 0.91 mm for those implanted asymmetrically (bag-sulcus). The differences between the lenses fixated in the bag and those asymmetrically situated were statistically significant (P less than .001). Circular looped lenses (360-degree encircling loop) decentered less (mean 0.28 mm) than modified C-loop lenses (mean decentration 0.63 mm) and modified J-loop lenses (mean decentration 0.60 mm). These differences were statistically significant (P less than .001). The differences were also significant if we considered only the lenses implanted in the bag (mean decentration 0.20 versus 0.59 and 0.54, respectively) (P less than .0001).

Aged↗
PubMed1991

Identification of a membrane glycoprotein found primarily in the prelysosomal endosome compartment.

Cells contain an intracellular compartment that serves as both the "prelysosomal" delivery site for newly synthesized lysosomal enzymes by the mannose 6-phosphate (Man6P) receptor and as a station along the endocytic pathway to lysosomes. We have obtained mAbs to a approximately 57-kD membrane glycoprotein, (called here plgp57), found predominantly in this prelysosomal endosome compartment. This conclusion is supported by the following results: (a) plgp57 was primarily found in a population of late endosomes that were located just distal to the 20 degrees C block site in the endocytic pathway to lysosomes (approximately 83% of the prelysosomes were positive for plgp57 but less than 5% of the early endosomes had detectable amounts of this marker); (b) plgp57 and the cation-independent (CI) Man6P receptor were located in many of the same intracellular vesicles; (c) plgp57 was found in the membranes of an acidic compartment; (d) immunoelectron microscopy showed that plgp57 was located in characteristic multilamellar- and multivesicular-type vacuoles believed to be prelysosomal endosomes; and (e) cell fractionation studies demonstrated that plgp57 was predominantly found in low density organelles which comigrated with late endosomes and CI Man6P receptors, and only approximately 10-15% of the antigen was found in high density fractions containing the majority of secondary lysosomes. These results indicate that plgp57 is a novel marker for a unique prelysosomal endosome compartment that is the site of confluence of the endocytic and biosynthetic pathways to lysosomes.

Animals↗
PubMed1989

Primary hyperparathyroidism: changes on biochemical and hormonal profile related to pregnancy.

A woman with mild asymptomatic hypercalcemia due to primary hyperparathyroidism became pregnant and her serum calcium normalized while her hypophosphatemia worsered. The PTH was low normal, but her urinary cAMP was elevated. In the second trimester of pregnancy a parathyroid adenoma was removed. After surgery, a transient hypocalcemia that normalized ten days later, a partial recovery of hypophosphatemia, and a 40% reduction of the elevated urinary cAMP excretion were observed. Pregnancy continued uneventful and a normal newborn was delivered. This case demonstrates the diagnostic difficulties posed by primary hyperparathyroidism during pregnancy, derived from inapparent changes in serum calcium and PTH. However, phosphorus and urinary cAMP deviations are significant constituting the basis for a correct diagnosis.

Adenoma↗