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Biomedical subjects

A Reuter

Publications and source records attributed to A Reuter.

At least 55 records · Page 3Linked to original sources
PubMed1984

Radioimmunoassay of leukocyte (alpha) interferon and its application to some clinical conditions.

A radioimmunoassay for human leukocyte interferon alpha (alpha IFN) has been developed, using tracer produced by recombinant DNA (IFLrA) and polyclonal rabbit antiserum against partially purified leukocyte IFN (PP alpha IFN). Sensitivity was 4 units/ml using sequential saturation. Only lymphoblastoid IFN showed complete cross reactivity. Serum alpha IFN concentrations were measured in normal subjects and in patients with acute viral infections, bone and joint diseases, and malignancies. Some cases in the first two groups of patients had significantly elevated serum levels compared with controls. The pharmacokinetics of alpha IFN were studied in treated cancerous patients. Radioimmunoassay and biological assay gave similar and closely correlated results. Radioimmunoassay is thus a useful method for the routine assay of alpha IFN, especially in biological fluids containing low concentrations.

Adolescent↗
PubMed1982

[Tumor markers].

Several substances, referred to as tumor markers, are associated with neoplasms development. The specificity of these cancer related substances or antigens depends on their nature (onco-fetal antigens, placental antigens) or on their concentration and physico-chemical forms (hormones, exocrine products, enzymes,...). On the basis of physico-chemical, immunochemical and biochemical analogies which exist between these tumor markers and substances normally found at particular times of life, a classification of these markers may be proposed. Tumor markers are almost constantly found within carcinoma cells by immunocytochemical techniques and are secreted by carcinoma explants in culture medium. On the hand, the release of tumor markers in biological fluids (blood, cerebrospinal fluid, urines,...) is less frequently detected by sensitive methods such as radioimmunoassay. Several factors are responsible for this discrepancy between the intra-tumoral presence of tumor markers and the lower incidence of their detection in biological fluids. These factors are discussed. These tumor markers have attracted considerable attention from pathologists and clinicians. Thus, detection of these substances, especially by immunocytochemical methods, may be related to a situation of neoplastic transformation and allow a functional classification superimposed to histological classification superimposed to histological classification of tumors. Moreover, ectopic production of hormones and/or neuromediators explains some clinical symptoms in cancer processes. Furthermore, products of normal cell activity at the origin of cancer (hormones, enzymes, exocrine products) when evidenced within the neoplastic cells or within serum might constitute a hormonal dependence index useful for therapeutical orientation. Finally, tumor marker levels are related to the local and systemic extension of the neoplasia and may be considered as valid index of prognosis. The determination of the levels of these tumor markers provides a quantitative criterion of the evolution of the neoplastic disorder and for following the efficacy or inefficacy of treatment.

Adrenocorticotropic Hormone↗
PubMed1981

[Radioimmunologic determination of human kininogen of high molecular weight].

HHW-kininogen has been purified from human plasma. We have then studied the optimal conditions for labeling this protein with 125I. This molecule has been used for the preparation of a radioimmunoassay. We have studied the analytical performances of our dosage : sensitivity, precision, accuracy and specificity.

Humans↗
PubMed1981

[AR-L 115 BS, comparison of human metabolite pattern and biotransformation with other species].

Following oral administration of 14C labelled 2-[(2-methoxy-4-methylsulfinyl)phenyl]-1H-imidazo[4,5-b]pyridine (AR-L 115 BS) to the rat, rabbit, dog, rhesus monkey, baboon and man the metabolic pattern in plasma and urine was compared and human urinary metabolites were isolated. None of the animal species investigated shows a metabolic pattern identical to that of man. The plasma of rat, dog and rabbit shows wide variation of metabolites with high amounts of two unpolar metabolites of AR-L 115 BS (sulfoxide), namely M0/2 identical with AR-L 114 BS (sulfone with regard to AR-L 115 BS) and M0/1 identical with AR-L 113 BS (sulfide). In comparison to man the urines of the animals show higher amounts of the sulfone (AR-L 114 BS) and the sulfide (AR-L 113 BS). A main pathway of the metabolism of the pyrido-imidazole of the AR-L 115 BS-type is the oxidative pyridine-ring cleavage leading to N-acetylated 5-aminoimidazoles. Further metabolites are characterised by a hydroxyl group in the 6-position of the pyrido-imidazole moiety. Besides the oxidation of tthe sulfoxide function to the sulfone we could also observe the thioether (sulfide) not only of the parent compound itself but also of some of the metabolites in the series of the AR-L 115 BS-biotransformation. The identification of the human urinary metabolites, was carried out by means of TLC, HPLC, UV-, MS- and NMR-spectroscopy.

Administration, Oral↗
PubMed1980

The metabolism of 8-methoxypsoralen in man.

8-Methoxypsoralen is metabolized rapidly and completely in man. Most of the metabolites presently known have their origin in a metabolic attack on the furan moiety yielding an aryl-diol and aryl-acetic-acid and are excreted as conjugates.

Biotransformation↗
PubMed1979

Enantiomeric purity of naproxen by liquid chromatographic analysis of its diastereomeric octyl esters.

A sensitive and specific analytical method was developed to determine the enantiomeric purity of naproxen. A simple derivatization of naproxen with (S)-(+)-2-octanol proceeded quantitatively and gave a mixture of diastereomeric esters displaying baseline separation on liquid chromatography. The ratio of these esters was the same as the ratio of enantiomers present in naproxen samples assayed. Reproducibility of the method was excellent.

Chromatography, Liquid↗
PubMed1977

[Anti-ulcer agent pirenzepine (LS 519)--a tricyclic compound with particular physico-chemical properties (author's transl)].

Compound 5,11-dihydro-11-[(4-methyl-1-piperazinyl)acetyl]-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one dihydrochloride (pirenzepine, L-S 519) represents a new type of drug in ulcer therapy. It has been selected for broad clinical investigations because of its outstanding pharmacological profile. Pirenzepine is devoid of any central activity despite certain structural similarities in relation to psychotropic tricyclic compounds. The extraordinary pharmacokinetic and pharmacodynamic behaviour of this compound can be easily derived from its inherent physicochemical properties: The inability to pass the blood-brain barrier as well as its inability to activate the unspecific and specific psychotropic receptors is due to thermodynamic factors.

Anti-Ulcer Agents↗
PubMed1976

Simultaneous assays of cancer-associated antigens in various neoplastic disorders.

Five tumor markers were measured simultaneously in serum by radioimmunoassay: carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), human chorionic gonadotrophin (HGC), the beta subunit of HCG, and Kappa casein. In a population of 935 normal subjects these antigens were undetectable or found within precise limits. In patients with tumors of various origins the rate of pathologically elevated levels was 72% at the beginning of the clinical course (194 cases). This high rate was primarily due to the simultaneous measurement of CEA, betaHCG, HCG, and casein. AFP was of little importance. The simultaneous measurement of these tumor markers may be one biochemical element of diagnosis of carcinoma, although this criterion is neither absolute nor specific, as 14.7% of patients with non-neoplastic disorders (234 cases) were positive for one antigen. In the presence of metastases (112 cases) the rate of pathologic levels of at least one antigen was increased: 86% due to CEA and casein assay at the same time as their absolute levels were increased. Surgical removal reduces the rate of positivity of these antigens to 37%. As was shown in patients with breast cancer, the rate was 10% when the tumor had been removed at Stage N- and 54% when it was removed at Stage N+. Thus, the persistence of pathologic levels could be correlated with the capacity for recurrence or metastases. Finally chemotherapy, radiotherapy, or both, do not decrease the rate of positivity of the tumor markers.

Adult↗
PubMed1976

Prolactin levels during the menstrual cycle.

The levels of prolactin, FSH, LH, oestradiol and progesterone were measured daily during fourteen ovulatory cycles. The behaviour of FSH, LH, oestradiol and progesterone was classical. Non-systematic changes occurred in prolactin levels during the course of the menstrual cycle with the highest level being either during the ovulatory period or during the luteal phase. However, the mean level of prolactin was significantly higher during the ovulatory and luteal phases than during the follicular phase. A direct relationship between oestradiol and prolactin levels was noted, although there was no correlation between prolactin on the one hand and FSH, LH and progesterone on the other.

Adult↗
PubMed1976

[Radioimmunoassay of thyroid stimulating hormone by sequential saturation].

The practice of sequential incubation in radio-immunoassay of TSH improves the sensitivity and precision without affecting the specificity compared with the method using simultaneous incubation of the constituents of the radio-immunological reaction. The determination of basic levels of TSH is more sensitive and more precise.

Cross Reactions↗