Search PubMed⌕ Search

Biomedical subjects

F Meyer

Publications and source records attributed to F Meyer.

At least 199 records · Page 11Linked to original sources
PubMed1989

[From natural to recombinant human erythropoietin. Biotechnological production of recombinant human erythropoietin].

Human erythropoietin (EPO), which occurs only in minute quantities in human plasma, has been isolated from urine of patients and purified to homogeneity. A partial amino acid sequence from tryptic digests of the purified protein was selected for oligodeoxynucleotide probe synthesis. These probes were used to isolate the EPO gene from a human gene bank. The isolated gene was engineered into a eukaryotic expression vector and introduced into chinese hamster ovary cells commonly used for recombinant protein production. A specific amplification of the EPO gene copy number in these cells led to the secretion of milligram quantities of EPO per liter of cell supernatant. This protein has similar characteristics to native urinary EPO, regarding its electrophoretic mobility, glycosylation pattern and biologic activities in vitro and in vivo. A scaled-up industrial process provides recombinant EPO for its clinical use.

Amino Acid Sequence↗
PubMed1989

Effects of flumethrin pour-on against Glossina palpalis gambiensis (Diptera, Glossinidae) during releases in a fly proof stable.

2000 males and females of Glossina palpalis gambiensis were released in the presence of a Zebu treated with flumethrin pour-on in a fly proof stable. From the first day after treatment until day 15, the flies were released at intervals of two days. The mortalities were highest during the first five days after treatment. With the exception of the first two releases the "knock down" effects were distinctly higher than the corresponding mortalities, ranging between 60% and 100% during the observation period.

Animals↗
PubMed1988

Mechanism of azide binding to chloroperoxidase and horseradish peroxidase: use of an iodine laser temperature-jump apparatus.

The kinetics of azide binding to chloroperoxidase have been studied at eight pH values ranging from 3.0 to 6.6 at 9.5 +/- 0.2 degrees C and ionic strength of 0.4 M in H2O. The same reaction was studied in D2O at pD 4.36. In addition, results were obtained on azide binding to horseradish peroxidase at pD 4.36 and pH 4.56. Typical relaxation times were in the range 10-40 microseconds. The value of kH/kD(on) for chloroperoxidase is 1.16, and kH/kD(off) is 1.7; corresponding values for horseradish peroxidase are 1.10 and 2.4. The H/D solvent isotope effects indicate proton transfer is partially rate controlling and is more important in the dissociation of azide from the enzyme-ligand complex. A mechanism is proposed in which hydrazoic acid binds to chloroperoxidase in a concerted process in which its proton is transferred to a distal basic group. Hydrogen bonding from the newly formed distal acid to the bound azide facilitates formation of hydrazoic acid as the leaving group in the dissociation process. The binding rate constant data, kon, can be fit to the equation kon = k3/(1 + KA/[H+]), where k3 = 7.6 X 10(7) M-1 S-1 and KA, the dissociation constant of hydrazoic acid, is 2.5 X 10(-5) M. The same mechanism probably is valid for the ligand binding to horseradish peroxidase.

Azides↗
PubMed1988

Dietary fat in relation to prognostic indicators in breast cancer.

The relation of diet, especially fat intake, to recognized prognostic indicators for breast cancer was investigated in 666 women with a newly diagnosed infiltrating breast carcinoma. Diet during the year preceding diagnosis was assessed by interview using a food frequency questionnaire covering the intake of 114 food items. Prognostic indicators included axillary node involvement at diagnosis, estrogen receptor status, and selected histologic features of the primary tumor such as nuclear grade, histologic grade, tubule formation, mitotic activity, and nuclear size of tumor cells. After adjustment for total energy intake, age, body weight, and tumor size at diagnosis, an increase in saturated fat intake was related to an increased frequency of node involvement at diagnosis among postmenopausal patients. In contrast, an elevation in polyunsaturated fat intake was related to a reduction of the percentage of patients with positive nodes at diagnosis. This relation was observed among both premenopausal and postmenopausal patients. Dietary fat was not related to the estrogen receptor status of tumors. No association was found between dietary habits and histologic features of the primary tumor. These data suggest that dietary fat may have an effect on the growth or spread of breast cancer during the preclinical phase of the disease and that this effect may vary according to the type of fat considered.

Aged↗
PubMed1988

Validity of self reported work history.

Many epidemiological studies of the relation between work and disease use information on work history obtained by interview from the study subjects. A validation study was undertaken to evaluate the accuracy of this information collected from 100 workers in a shipbuilding industry. The information furnished by the workers was compared with that present in the company's registers. The work history (job titles and starting dates) was relatively accurate and the validity varied with the number of events to declare and with their duration; it also depended on the type of information and the precision required.

Adult↗
PubMed1988

[Autoimmune hemolytic anemia during treatment with cyclosporin after liver transplantation].

Hemolytic anemia was observed in a 36 year-old liver transplant patient. The immunosuppressive regimen included cyclosporine A and prednisolone. Hemolysis appeared a few days after amoxicillin treatment. The presence of anti-D allo-antibodies, auto-antibodies active against erythrocytes, and an immuno-allergic phenomenon against erythrocytic membrane coated by cyclosporine was demonstrated. Increase of daily dose of prednisolone without modification of cyclosporine doses was followed by the disappearance of allo- and auto-sensitization. The role of amoxicillin in promoting these hemolytic phenomenons may be suggested.

Adult↗
PubMed1987

Reversible silencing of enhancers by sequences derived from the human IFN-alpha promoter.

The virus-responsive element of the IFN-alpha 1 promoter, VRE(IFN alpha), comprises two imperfect 19 bp repeats, repA and repB. VRE(IFN alpha), tetrameric repA, and tetrameric GAAAGT (a subsequence of repB) or tetrameric AAGTGA conferred inducibility on a reporter gene when placed upstream of a complete or truncated promoter. Induced transcription was weak with a minimal promoter (TATA box only), but was strongly stimulated by the SV40 enhancer placed immediately upstream of the inducible element. Surprisingly, under noninduced conditions, tetrameric repA, GAAAGT, and AAGTGA (but not VRE(IFN alpha)) completely silenced enhancement of constitutive transcription by the SV40 72 bp repeat when interposed between the latter and the TATA box; silencing was fully abrogated by induction.

Animals↗
PubMed1987

Maternal and neonatal morbidity in instrumental deliveries with the Kobayashi vacuum extractor and low forceps.

Risks to the mother and newborn associated with the use of the Kobayashi Silastic vacuum extractor (n = 293) were compared with those associated with the use of low forceps (n = 468) in a retrospective chart review. Third or fourth degree perineal tears and vaginal and cervical lacerations were all observed less frequently among women delivered with the vacuum extractor. The need for post-partum bladder catheterization was also reduced for these women. Babies born by the means of the vacuum extractor ran an increased risk of cephalhematoma and neonatal jaundice. No difference in major neonatal morbidity was observed between the two groups. The Kobayashi instrument appears to be a useful alternative to forceps in low vaginal instrumental deliveries.

Birth Injuries↗
PubMed1987

[Herovici's picropolychromium. Application to the identification of type I and III collagens].

A staining technique differentiating two colorimetric types of connective fibers had been proposed by Herovici previously to the identification of collagen types. This technique has been applied to skin, lung and liver specimens and the results have been compared with immunotyping and literature data on collagen types I, III and IV. The conclusions are focused on the ability of the technique to identify at a first approach collagen types I and III, which are known to be of crucial importance in mechanical tissular properties.

Collagen↗
PubMed1987

[Some aspects of the management of patients with epilepsy in pregnancy].

The care of pregnant epileptics calls for a high measure of personal attention and material expenditure. Above all, it means close cooperation between the epileptic specialist, the obstetrician, and the clinical pharmacologist. The need for this collaboration, and its effectiveness, are demonstrated by means of practical examples, with special consideration of blood level.

Adolescent↗
PubMed1986

Ophthalmology in Chile.

The practice of ophthalmology in Chile does not differ much from that in the United States. Basic ophthalmologic knowledge is the same, and common clinical problems are solved in the same way. The difference becomes evident in the more complex clinical problems. We have the knowledge and ability to perform the treatment but come up against the problem of high cost of technical instruments. Vitreous surgery, intraocular lens surgery, and laser treatments are performed, but we have to overcome the obstacles of obtaining the expensive and limited number of instruments. Perhaps, a US ophthalmologist will not understand this problem because, as I became aware during my stay as a fellow at The Wilmer Institute, Baltimore, and at other times when I have visited the United States, these difficulties do not arise. Lasers are bought, instruments are ordered by telephone, and manufacturers swamp the doctors with propaganda and offers of "call toll free for 30 days on trial." On the other hand, we know that, due to our efforts and using the means at our disposal, we have managed to keep the specialty at a high level, solving health problems and making the practice of ophthalmology pleasant in this beautiful country. Chilean ophthalmology has great prestige in South America. It has been the forerunner in the instruction of ophthalmologists, creating a method of teaching and of systematic specialization that has been unique in Latin America. It is an example to other branches of medicine in Chile. Although ophthalmologists are badly distributed in the country, considering our particular geographic and economic conditions, they fulfill their objectives in providing adequate visual health care for the population. This has come about through the combined effort of all Chilean ophthalmologists based on the example of their predecessors. Also, there has been a sense of solidarity among us, with responsibility and enthusiasm shown in practicing and in communicating ophthalmic precepts altruistically to the coming generations.

Chile↗
PubMed1986

Endogenous sex hormones, prolactin, and breast cancer in premenopausal women.

Forty-one women with breast cancer and 119 controls participated in a case-control study of the relation of endogenous sex hormones to breast carcinoma in premenopausal women. During the follicular phase of the menstrual cycle, one overnight urine specimen was collected. During the luteal phase, urine and blood specimens were obtained. 17 beta-Estradiol, sex hormone-binding globulin, progesterone, and prolactin were measured in plasma, whereas estrogen metabolites (estrone, estradiol, and estriol) and pregnanediol were assessed in the urine. Breast cancer was associated with high-plasma estradiol and prolactin and with low progesterone. Similar but weaker associations were observed for urinary estrogens and pregnanediol in the luteal phase.

Adult↗