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Biomedical subjects

M Reyes

Publications and source records attributed to M Reyes.

At least 91 records · Page 5Linked to original sources
PubMed1984

Brain tumors at a nuclear facility.

In response to an observed excess risk of brain tumor deaths among workers at the Rocky Flats Nuclear Facility (Colorado), a case-control study of all (n = 16) primary brain tumor deaths occurring among white males employed during 1952 through 1977 was conducted to investigate their relationship with occupational radiation/nonradiation exposures. For each case, four controls were individually matched on year of birth and period of employment. Although limited by a small number of cases, our study showed no statistically significant association between brain tumor death and exposure to internally deposited plutonium, external radiation, or other occupational risk factors.

Adult↗
PubMed1983

A new chromatographic method for the fractionation of hyaluronic acid.

Sodium hyaluronate from rooster comb, umbilical cord, bovine vitreous and a special commercial hyaluronic acid preparation, "HealonR" have been fractionated at 4 degrees C on DEAE-Sephacel columns using salt gradients from 0 leads to 0.4M NaCl. All samples examined displayed a high degree of polydispersity. The number of well separated fractions observed in these chromatograms ranges from 10-30 depending on the source of the material. A molecular weight distribution effect does not seem to be the main factor controlling this fractionation as no differences could be observed when the limiting viscosity numbers (eta) for numerous fractions isolated from the same sample were compared with each other. As no galactosamine, sulfate or phosphate is found directly linked to these fractions, it is suggested that disaggregation of an hyaluronate molecular aggregate could be the basis for this fractionation.

Animals↗
PubMed1983

An update of epidemiologic studies of plutonium workers.

Retrospective and prospective epidemiologic studies are being conducted as part of a national survey of plutonium workers at four Department of Energy facilities (Los Alamos, NM; Rocky Flats, CO; Mound Laboratory, OH; and Savannah River, SC). A preliminary analysis of mortality was done for all white males who have worked at the Rocky Flats Plant during the period 1952-79. The 452 observed deaths were significantly fewer than the 831 expected for all causes. The 107 deaths due to all malignant neoplasms were also significantly fewer than the 167 expected from these diseases. Expected deaths were derived from age and calendar-specific death rates for U.S. white males. Deaths reported for benign and unspecified neoplasms numbered eight versus an expected two, a significant elevation. These tumors, all intracranial, are the subject of a case-control study to be reported later. Subdividing the cohort on the basis of plutonium exposures and external radiation exposures results in similar overall findings. The benign and unspecified neoplasms, however, were not significantly high in the plutonium-exposed group.

Adult↗
PubMed1983

Muscle phosphoglycerate mutase (PGAM) deficiency: a second case.

Muscle phosphoglycerate mutase (PGAM) activity was markedly decreased (6% of the normal mean) in a 17-year-old girl with recurrent myoglobinuria after intense exercise. Muscle biopsy showed increased PAS stain; glycogen concentration was twice normal. Studies of anaerobic glycolysis in vitro showed decreased lactate production with glycogen, and with all hexose phosphate glycolytic intermediates, which was corrected by addition of purified PGAM to the reaction mixtures. A defect of the M subunit of PGAM was documented by electrophoretic, heat lability, and mercury inhibition studies. Intermediate PGAM activities (39 and 50% of normal) were found in muscle biopsies from the patient's asymptomatic parents. These data confirm the clinical, morphologic, and biochemical features described in the first patient with PGAM deficiency and suggest autosomal-recessive transmission of the trait.

Adolescent↗
PubMed1983

Isolation and characterization of ichthyosan from tuna vitreous.

Ichthyosan has been prepared from tuna vitreous. Glucuronic acid was found to account for the total uronic acid content of the macromolecule, while the hexosamine content was a mixture of N-acetyl-glucosamine and N-acetyl-galactosamine. When ichthyosan was gel filtered on Sepharose 2B or Sephacryl S-300, using sodium or calcium chloride, the elution profile of the column gave only one peak indicating no separation between glucosamine and galactosamine containing fractions. Similar results were obtained when ichthyosan was chromatographed on DEAE-cellulose using a salt gradient both in the presence and absence of 7.0 M urea. When ichthyosan was gel filtered in 4.0 M guanidine-HCL and subsequently chromatographed on DEAE-Sephacel or DEAE-cellulose, three well separated fractions were present. The two major fractions (II and III) were characterized as chondroitin and hyaluronic acid respectively; while fraction I representing about 3-5% of the total polysaccharide content of ichthyosan was identified as a keratan-like molecule. The same pattern was obtained when ichthyosan was digested with proteolytic enzymes and subsequently chromatographed on DEAE-cellulose or DEAE-Sephacel. Based on these findings it is concluded that in ichthyosan chondroitin, hyaluronate and keratan-like molecular chains are bound to proteins in non-covalent linkages.

Animals↗
PubMed1982

Evaluation of Social Security follow-up of some southwestern populations.

A study of the completeness of death ascertainment through the Social Security Administration (SSA) was undertaken. Groups of subjects of known vital status were submitted by the Los Alamos National Laboratory to the SSA for a mortality record search. Correctly ascertained deaths ranged from 77% to 90% among males and from 53% to 76% among females. A duplicate record search one year later raised correct ascertainment to 88% to 94% of male deaths and to 73% to 87% of female deaths. Death ascertainment appeared to be independent of ethnicity (Anglo and Hispanic), cause of death, location of death, and year of death. Age at time of death was strongly related to death ascertainment. Individuals 65 years of age and over were identified much more accurately than persons less than 65 years of age. Lack of incentive to report deaths of persons under retirement age is believed to be responsible. The age of an industrial facility and of the work force may have a major influence on the adequacy of mortality ascertainment through social security.

Age Factors↗
PubMed1979

[Coproantibodies in intestinal amebiasis].

E. histolytica tissue invasion induces IgG and IgM and probably IgA serum antibody formation of different types in the intestinal mucosa. 21 children with intestinal invasive amebiasis were studied. Samples were taken from peripheral blood and stools during diagnostic studies and three weeks later. Contraimmunoelectrophoretic antibody determinations and indirect hemagglutination tests IH were made in an attempt to demonstrate its true nature. During the acute phase (first sample), results showed antibodies against amoeba in stools by CIE in 57 per cent and by IH in 80 per cent; in serum, results were 38 and 76 per cent respectively. In the second sample and three weeks after diagnosis was established a decrease in the number of patients with coproantibodies against amoeba was observed and the number of patients with serum antibodies increased. We are also providing evidence that supports the IgG and IgA nature of coproantibodies against amoeba. These results suggest the presence of a local immunological reaction in invasive amebiasis.

Antibodies↗
PubMed1977

Hemisphaericin-D, a dialysable and polymerizable protease found in Bromelia hemisphaerica.

Proteolytic activity was detected outside dialysis bag filled with Bromelia hemisphaerica fruit juice. The dialysable protease was concentrated and purified from small molecular weight contaminants on Sephadex G-10 columns. Acrylamide gel electrophoresis of the dialysable protease, in the presence of SDS and 2-mercaptoethanol, demonstrated a single protein band of about 8000 daltons mol. wt. The same single band with identical mobility was shown with Hemisphaericin, the enzyme retained inside the dialysis bag. The small protease, named Hemisphaericin-D was antigenic in rabbits and the antibodies cross-reacted fully with Hemisphaericin. Hemisphaericin-D appears not to be a degradation product of Hemisphaericin.

Cysteine Endopeptidases↗
PubMed1976

Localized myokymia caused by peripheral nerve injury.

One year after a gunshot wound in the popliteal fossa, a 30-year-old man began to experience cramps and myokymia in the left gastrocnemius muscle. Myokymia was characterized by vermicular fibrillary movements localized to the gastrocnemius muscle and accompanied by plantarflexion and dorsiflexion of the toes. Neurologic examination, nerve conduction velocities, electromyograms, and muscle biopsy findings showed affection of left common peroneal and posterior tibial nerves. The myokymia disappeared during sleep, spinal anesthesia, and treatment with carbamazepine.

Adult↗
PubMedDate not supplied

Type III radical hysterectomy after induction chemotherapy for patients with locally advanced cervical carcinoma.

Neoadjuvant chemotherapy followed by surgery is a promising approach in locally advanced cervical carcinoma. The aim of this study was to evaluate the feasibility, technical aspects, and clinical results of surgery after induction chemotherapy in this patient population. Forty-one untreated cervical carcinoma patients staged as IB2 to IIIB received three 21-day courses of cisplatin 100mg/m2 on day 1 and gemcitabine 1000 mg/m2 on days 1 and 8 followed by surgery or concomitant chemoradiation. The response to chemotherapy, operability, surgical/pathological findings, disease-free period, and survival of the surgically treated patients were evaluated. All 41 patients were evaluated for toxicity and 40 were evaluated for response. The overall objective response rate was 95% (95% confidence interval 88%-100%), and was complete in three patients (7.5%) and partial in 35 (87.5%). Granulocytopenia grades 3/4 occurred in 13.8% and 3.4% of the courses, respectively, whereas nonhematological toxicity was mild. Twenty-three patients underwent type III radical hysterectomy. Mean duration of surgery was 3.8 h (range 2:30-5:20), median estimated blood loss was 670 ml and median hospital stay was 5.2 days. Intraoperative complications occurred in one case (venous injury). In all but one case the resection margins were negative. Four patients (17%) had positive nodes (one node each); six (26%) had complete pathologic response, three (13%) had microscopic; and 14 (60%) macroscopic residual disease. At 24 months of maximum follow-up (median 20), the disease-free and overall survival rates were 59% and 91%, respectively. Induction chemotherapy with cisplatin/gemcitabine produced a high response rate and did not increase the difficulty of surgery. Operating time, blood loss, intraoperative complications, and hospital stay were all within the range observed for type III hysterectomy in early stage patients. We therefore conclude that type III radical hysterectomy is feasible in locally advanced cervical cancer patients who respond to chemotherapy.

Adolescent↗
PubMedDate not supplied

Cytotoxic triterpenoids from Erica andevalensis.

The cytotoxic activity of two pentacyclic triterpenoids (ursolic acid and alpha-amyrine) isolated from the methanolic extract of the aerial parts from Erica andevalensis, whose structures have been established on the basis of spectroscopic and chemical evidence, has been assessed against three human cancer cell lines, TK-10 (renal adenocarcinoma), MCF-7 (breast adenocarcinoma) and UACC-62 (melanoma), recommended by NCI (National Cancer Institute) and we also evaluated the antimitotic effect in root meristematic cells of Allium cepa. Ursolic acid was found to possess the highest cytotoxic activity.

Adenocarcinoma↗