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Biomedical subjects

E Luna

Publications and source records attributed to E Luna.

At least 37 records · Page 2Linked to original sources
PubMed1994

Identification of a novel, N7-deoxyguanosine adduct as the major DNA adduct formed by a non-bay-region diol epoxide of benzo[a]pyrene with low mutagenic potential.

A metabolite of benzo[a]pyrene, 9-r,10-t-dihydroxy-7,8-c-oxy-7,8,9,10- tetrahydrobenzo[a]pyrene (BPDE-III), that is not thought to be involved in carcinogenesis has nevertheless been shown to bind extensively to DNA in vitro. The adducts formed by this non-bay-region diol epoxide in Chinese hamster ovary cells are much less mutagenic than those formed by an isomeric diol epoxide that is carcinogenic. We have isolated and characterized three major adducts formed by in vitro reaction of BPDE-III with DNA. The major adduct, accounting for over half of the total is formed by reaction of BPDE-III with the N7 position of dGuo and is recovered after enzymatic digestion as an N7-Gua adduct. A second major adduct involves the N2 position of dGuo, while the third adduct is tentatively identified as a C8-substituted dGuo. Little or no reaction with deoxyadenosine residues is detected. The N7 adduct is unstable in DNA at 37 degrees C and is released as the modified base with a half-life of about 24 h. This adduct lability apparently leads to single-strand breaks and alkali-sensitive sites in the DNA and may account in part for some of the biological properties of BPDE-III adducts. This represents the first description of an N7-dGuo adduct that is formed in DNA as the major adduct by a diol epoxide derived from a carcinogenic polycyclic aromatic hydrocarbon.

Animals↗
PubMed1994

Reactive eosinophilic pulmonary vascular infiltration in patients with spontaneous pneumothorax.

Prominent nonnecrotizing eosinophilic inflammation of muscular pulmonary arteries was seen in resected lung tissue from two patients with spontaneous pneumothorax. Other histologic features included reactive eosinophilic pleuritis (REP) and fibrobullous disease. Eosinophilic vascular infiltration was not contiguous to REP. In neither patient was there a specific and recognized cause of eosinophilic vasculitis. Both patients are without pulmonary symptoms 1 and 4 years after pneumothorax. Eosinophilic vascular infiltration initially suggested the diagnosis of allergic angiitis or pulmonary eosinophilic granuloma. These diagnoses were excluded by clinical and morphologic data. We subsequently reviewed 30 cases of lung tissue resected from patients with pneumothorax and found REP in 18 patients (60%) and mild pulmonary vascular and perivascular eosinophilia in five patients (17%). REP was present in all cases with eosinophilic vascular infiltration. We conclude that this eosinophilic vascular lesion is an unusual reaction in patients with REP and pneumothorax. Occasionally this lesion mimics allergic angiitis or eosinophilic granuloma. The pathogenesis is probably related to vascular transport of eosinophils to the injured pleural surface.

Adult↗
PubMed1994

Exercise echocardiographic correlates of transient dilatation of the left ventricular cavity on exercise thallium-201 SPECT imaging.

Transient dilatation of the left ventricular cavity on exercise thallium perfusion imaging is recognized as a marker of significant coronary disease, but the mechanisms that produce this finding are not fully understood. We studied 32 patients who underwent exercise thallium imaging and exercise echocardiography to determine the changes in left ventricular cavity size that underlie transient dilatation. Left ventricular area from the apical four-chamber view was used to approximate left ventricular cavity size. There were 24 patients who did not have transient dilatation (group 1) and 8 patients who did have transient dilatation (group 2) on thallium imaging. Systolic area decreased from rest to exercise in group 1 patients but not in group 2 patients. There was no significant change in diastolic area from rest to exercise in either group 1 or group 2 patients. Thus, exercise-induced systolic dysfunction, manifested as a failure to decrease left ventricular systolic cavity size in exercise, may be an important mechanism in producing scintigraphic transient dilatation.

Echocardiography↗
PubMed1993

Solution conformation of the (+)-cis-anti-[BP]dG adduct in a DNA duplex: intercalation of the covalently attached benzo[a]pyrenyl ring into the helix and displacement of the modified deoxyguanosine.

This paper reports on the solution structure of the (+)-cis-anti-[BP]dG adduct positioned opposite dC in a DNA oligomer duplex which provides the first experimentally based solution structure of an intercalative complex of a polycyclic aromatic hydrocarbon covalently bound to the N2 of deoxyguanosine. The combined NMR-energy minimization computation studies were undertaken on the (+)-cis-anti-[BP]dG adduct embedded in the same d(C5-[BP]G6-C7).d(G16-C17-G18) trinucleotide segment of the complementary 11-mer duplex studied previously with the stereoisomeric trans adducts. The exchangeable and nonexchangeable protons of the benzo[a]pyrenyl moiety and the nucleic acid were assigned following analysis of two-dimensional NMR data sets in H2O and D2O solution. The solution structure of the (+)-cis-anti-[BP]dG-dC 11-mer duplex has been determined by incorporating intramolecular and intermolecular proton-proton distances defined by upper and lower bounds deduced from NOESY data sets as restraints in energy minimization computations. The benzo[a]pyrene ring of [BP]dG6 is intercalated between intact Watson-Crick dC5.dG18 and dC7.dG16 base pairs in a right-handed DNA helix. The benzylic ring is in the minor groove while the pyrenyl ring sacks with flanking dC5 and dC7 bases on the same strand. The deoxyguanosine ring of [BP]dG6 is not Watson-Crick base paired but displaced into the minor groove with its plane parallel to the helix axis and stacks over the sugar ring of dC5. The dC17 base on the partner strand is displaced from the center of the helix toward the major groove by the intercalated benzo[a]pyrene ring. This intercalative structure of the (+)-cis-anti-[BP]dG-dC 11-mer duplex exhibits several unusually shifted proton resonances which can be readily accounted for by the ring current contributions of the deoxyguanosine and pyrenyl rings of the [BP]dG6 adduct. Several phosphorus resonances are shifted to low and high field of the unperturbed phosphorus spectral region and have been assigned to internucleotide phosphates centered about the [BP]dG6 modification site. These studies define the changes in the helix at the central trinucleotide segment needed to generate the intercalation site for the covalently bound (+)-cis-anti-[BP]dG adduct.(ABSTRACT TRUNCATED AT 400 WORDS)

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1993

Disappearance of a left ventricular aneurysm on radionuclide ventriculography due to formation of a mural thrombus.

Radionuclide ventriculography is an accepted method for diagnosing left ventricular aneurysms, but false-negative studies have been associated with a mural thrombus filling the left ventricular cavity. We describe a patient with a left ventricular aneurysm due to myocardial infarction whose aneurysm scintigraphically "disappeared" from serial radionuclide ventriculograms. This was documented echocardiographically and pathologically to be due to the formation of a large mural thrombus. Review of the literature suggests that radionuclide ventriculography and echocardiography may be complementary techniques in the diagnosis of left ventricular aneurysm. Echocardiography may remain diagnostic when a mural thrombus has caused the loss of the characteristic scintigraphic findings on radionuclide ventriculography.

Adult↗
PubMed1992

[Comparison of the new Granada medium and the ICON-strep B test in the detection of group B streptococci in pregnant patients].

The detection of group B streptococci by the ICON Strep-B test an enzyme immunoassay, and culture in new Granada Medium was compared in tubes and plates in a total of 200 vaginal specimens from pregnant women. The group B streptococci were cultured in new Granada medium from 33 of these specimens (incidence of 16.5%). Compared with culture in new Granada medium, the sensitivity and specificity of the ICON-Strep B test were 66.6 and 100%, respectively. Because of their poor sensitivity, we do not recommend the use of these rapid test as the only basis for GBS detection.

Carrier State↗
PubMed1991

Use of differential scanning potentiometry in pharmaceutical analysis.

The use of differential scanning potentiometry (DSP) to assay pure drugs and mixtures is illustrated through a set of model cases. The profiles obtained by scanning glycine (0.3 mmol), sulfanilamide (0.3 mmol), epinephrine (0.06 mmol), and norfloxacin (0.05 mmol) are reported, as well as the areas (A+, A-, and At) obtained in each scan. Such information is useful to assess identity and/or chemical purity and to get the pKa of the ionizing groups of the drugs. The degree of hydrolysis of a parenteral solution of procaine hydrochloride is also determined through DSP as an example of mixture assay. Comparison with conventional aqueous acid-based potentiometry shows that the new technique exhibits much better performance to assay small samples or samples carrying weak acidic and/or basic groups.

Chemistry, Pharmaceutical↗
PubMed1989

Hepatic localization of Tc-99m MAA during lower extremity venography.

Hepatic localization of macroaggregated albumin particles has been observed previously in both superior and inferior vena cava obstruction. These reports have described focal regional hepatic uptake in porta hepatis or the left hepatic lobe in cases of SVC and IVC obstruction as well as global hepatic uptake in IVC obstruction. In this report of an unusual case of hepatic uptake of MAA during lower extremity venography, the entire liver and lungs were simultaneously visualized, presumably due to portal-to-systemic collateral flow pathways in the presence of inferior vena cava obstruction.

Humans↗
PubMed1988

Organ and skeletal growth in mice with a major gene for rapid postweaning growth.

Growth of liver, heart, kidney and femur in mice with a major gene for rapid postweaning growth (hg/hg, line Ch) was compared to that of their normal controls (Hg/-, line CH). Male mice of both lines were sacrificed at 7 day intervals from 21 to 56 days of age. By day 56 mice of line Ch weighed 40.1 g and individuals of line CH weighed 30.2 g. At sacrifice, individuals were weighed, the naso-anal length and tail length measured and the liver, heart and kidney were removed and weighed. The left femur was also removed and its length measured. Significant differences between lines were detected for all traits observed when examined on an uncorrected basis. This significance disappeared when organ weights were adjusted by body weight at sacrifice through covariance analysis. Similarly, there was no significant in femur length across lines when bone lengths were adjusted for naso-anal length. Only differences in tail length remained significant after adjustment for body length. These results suggest that the impact of the hg allele is of a fundamental and general nature, with little impact on specific tissues or functions of growth.

Animals↗
PubMed1987

Women on women.

Explore the source record for details and available documents.

Female↗
PubMed1984

The association of clathrin fragments with coated vesicle membranes.

The association between clathrin triskelions and the clathrin-stripped membranes of coated vesicles has been investigated using a filter assay to separate bound from unbound clathrin. The filter assay is more sensitive and less cumbersome than a sedimentation assay used previously (1). While confirming the high affinity interaction between clathrin and the vesicle membrane, our results yield Scatchard plots that are curvilinear and consistent with a positively cooperative interaction between clathrin and the vesicle membranes. Controlled digestion with trypsin removes the distal portions of the triskelion legs leaving the proximal 31 nm portions that form the hub of the triskelions. These hubs are trimers of large 112,000- and 124,000-dalton fragments of clathrin heavy chains. They competitively inhibit the binding of 125I-labeled intact triskelions to stripped vesicles with a KI identical to the KD for the association of 125I-labeled intact triskelions to stripped vesicles. Furthermore, these large fragment trimers bind to stripped vesicles with approximately the same high affinity as do intact triskelions and also show evidence of a positively cooperative interaction. It is concluded that clathrin binds to coated vesicles by an interaction that is mediated by the proximal 112,000-dalton fragment of the clathrin heavy chains.

Animals↗
PubMed1984

Effects of solvent medium on solubility III: Hydrophilic-lipophilic character exhibited by some functional groups having oxygen or nitrogen in ethanol-water.

Solubility data of nine derivatives of the structure p-X1-C6H4-X2 in ethanol-water at 25 degrees C are reported. The correlation of such sets of data by log Sy = Py X log Sx + C yields the medium effect parameter Py for a variety of functional groups possessing either oxygen or nitrogen. Py accounts for the hydrophilic-lipophilic character exhibited by each group.

Chemical Phenomena↗
PubMed1984

Effects of solvent medium on solubility IV: Comparison of the hydrophilic-lipophilic character exhibited by functional groups in ethanol-water and ethanol-cyclohexane mixtures.

Solvent effects on the solubility of a set of structurally related solid compounds (Ax, Ay, etc.) in ethanol-water (system 1) and ethanol-cyclohexane (system 2) are compared by the equation, log Sy = Py log Sx + C. For a given structural change, Ax----Ay, it yields the respective medium-effects parameters, Py1 and Py2. They are used to compare the sensitivity of both solvent systems with the structural changes in the substrates by the equation, delta 12 = (Py1 - 1) - (1 - Py2). Structural changes involving the full replacement of the hydrogen atoms bonded to either O or N afford delta 12 less than 0, while those involving solely an increase in the alkyl chain of the substrates yield delta 12 greater than 0. A structural change where the donor-acceptor capacity of hydrogen bonding is maintained yields a delta 12 approaching zero.

Chemical Phenomena↗
PubMed1984

Photon absorptiometry for non-invasive measurement of bone mineral content.

Bone mineral content of the distal radius was determined in 106 patients by single photon absorptiometry using iodine-125 monochromatic source. The technique provided a reliable means to assess the degree of mineral loss in conditions such as osteoporosis, renal osteodystrophy in patients on chronic maintenance dialysis, subjects on long-term steroid therapy, and those with diabetes mellitus. It is more sensitive than conventional radiography and completely noninvasive compared to bone biopsy. It is suggested that photon absorptiometry is a simple, sensitive, and reliable technique for assessment and follow-up of the bone mineral content in a host of disorders associated with bone demineralization.

Adult↗
PubMed1984

Detection of gastrointestinal bleeding by radionuclide scintigraphy.

Scanning with Technetium 99m labeled autologous red blood cells was performed in 59 patients with clinical suspicion of acute and/or intermittent, chronic gastrointestinal bleeding. In 36 patients (61%), a definite site of bleeding could be demonstrated. A strong correlation with other modalities such as upper and lower gastrointestinal endoscopy, contrast angiography, and surgical exploration was found. Overall sensitivity of the procedure was 91%; specificity 100% and accuracy 93.3%. It is suggested that radionuclide scintigraphy provides a completely noninvasive, simple, and sensitive procedure which may be routinely used for the detection and localization of gastrointestinal bleeding.

Adult↗