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Biomedical subjects

T J O'Brien

Publications and source records attributed to T J O'Brien.

At least 127 records · Page 7Linked to original sources
PubMed1983

Surgical treatment of renal hyperparathyroidism.

Renal hyperparathyroidism can be a major clinical problem in those receiving dialysis treatment and in those having renal transplants. This review of 66 patients during a five year period has led us to believe that laboratory data are useful for confirming the clinical diagnosis or for following the outcome of medical or surgical therapy. The screening for renal hyperparathyroidism should be on clinical grounds and not on isolated biochemical tests. All patients with renal failure, whether receiving dialysis therapy or renal transplantation, are at risk for having renal hyperparathyroidism develop. A careful assessment of the clinical and biochemical data is required to ensure proper patient selection for operation. Bone disease and persistent pruritus unresponsive to medical management remain the principle clinical indications for operation. Our preferred procedure is the standard subtotal parathyroidectomy.

Adenoma↗
PubMed1982

Successful renal transplantation in a patient with anaphylactic reaction to Solu-Medrol (methylprednisolone sodium succinate).

Following the intravenous infusion of Solu-Medrol (methylprednisolone sodium succinate), anaphylactic shock developed in a 41 year old man on two consecutive occasions, six weeks apart. Intracutaneous testing with different components of he Solu-Medrol Mix-O-Vial demonstrated that the patient was allergic to methylprednisolone sodium succinate but not to other ingredients. In view of the recent increase in the popularity of steroid pulse therapy, we believe that all clinicians should be aware of this unusual and potentially fatal reaction to Solu-Medrol.

Adult↗
PubMed1982

Double antibody immunoradiometric assay of hGH employing a terminal labeling technique.

A method is described, and validated for hGH, using a double antibody immunoradiometric assay and a universal antibody coupled to a chelating moiety that can be labeled as the terminal step in the assay procedure. This technique, usable for any antigen, precludes the need for radiolabeled specific antibodies, and because of the short-lived radionuclide used in the terminal labeling step, generates no radioactive waste. The assay itself uses a specific first antibody coupled to a solid support (paper disc) to which the antigen binds. A specific second antibody from a second species is then attached to the solid phase retained antigen. Now a third antibody is attached, which has been generated from a third species against the second antibody acting as an antigen, and which carries transferrin as a chelating moiety. This final complex is labeled with 113mIn and the plot of the percentage of the total activity bound against the hGH concentration provides the derived values for the antigen levels present in the assay solution.

Antibodies↗
PubMed1982

Down's syndrome phenotype and autosomal gene inactivation in a child with presumed (X;21) de novo translocation.

A 3 1/2-year-old female with clinical features of Down's syndrome was found to have extra chromosome material on the long arm of one of the X chromosomes, 46,XXq+. The parental karyotypes were normal. In the light of the clinical features of the proband an the banding characteristics of the extra chromosome material, the patient was thought to have a de novo (X;21) translocation. The results of late replication studies with BUdR and enzyme superoxide dismutase (SOD) assays in the proband suggest that: (1) the presumed (X;21) translocation chromosome was the late replicating chromosome; (2) the spread of inactivation extended from the Xq segment of the translocation chromosome to the proximal part of the segment derived from chromosome 21, leading to the inactivation of the autosomal gene for enzyme SOD; (3) the remaining distal portion of the (X;21) translocation chromosome, a part of a segment presumably derived from chromosome 21, was spared from the spread of inactivation so that this part was still genetically active and responsible for the Down's phenotype; (4) therefore, the main determinants for a Down's phenotype may be located more distally (q22.2 or q22.3 or both) than the SOD gene (q22.1) on the long arm of chromosome 21.

Bromodeoxyuridine↗
PubMed1982

A plasma/serum estrogen-binding protein distinct from testosterone-estradiol-binding globulin.

A plasma/serum estrogen-binding protein (E2BP) which is distinct from testosterone-estradiol-binding globulin (TEBG) has been documented. This high affinity, low capacity estrogen binder is readily detectable in the mannoglycoprotein fraction of serum or plasma. It can be distinguished from TEBG by 1) its isoelectric elution pH (pH 3.9 as distinct from pH 4.9 for TEBG); 2) its sedimentation value on sucrose gradients (a lower sedimentation value compared to TEBG); and 3) its steroid specificity (a high affinity for diethylstilbestrol with essentially no affinity for dihydrotestosterone or testosterone, in contrast to TEBG which has no affinity for diethylstilbestrol and a high affinity for dihydrotestosterone and testosterone).

Carrier Proteins↗
PubMed1981

Modulation of protein expression in endometrial adenocarcinoma cells by in vitro exposure to estradiol and progesterone.

Protein maps of in vitro hormone-modulated adenocarcinoma cells from an endometrial tumor are described. It is noted that mapping of tumor tissues by means of the two-dimensional analysis described by O'Farrell and associates of 35S-methionine-labeled proteins can provide a characteristic map for each tumor and that the methionine-containing proteins of tumor cells can be independently modulated by the in vitro additions of estradiol and progesterone. Such protein modulation could be indicative of hormonal therapeutic responsiveness of individual endometrial adenocarcinomas and other hormone receptor-positive tumors. Tumor maps may further provide data for the identification and isolation of new tumor markers which might be correlated with the radiotherapeutic and chemotherapeutic sensitivity of the malignancy.

Adenocarcinoma↗
PubMed1981

Evidence for the existence of an androgen binding protein in hydatidiform mole vesicles.

Extracts of hydatidiform mole vesicles and the fluid contained in these vesicles were shown to contain a trophoblastic androgen binding protein. This protein was found to be distinct from serum testosterone-estradiol binding globulin (TEBG) by its isoelectric point, its affinity for dihydrotestosterone (DHT) and by Concanavalin A binding. The elution pH of this binding protein was shown to be 4.6, whereas that of TEBG was pH 5.2-5.3. The apparent dissociation constant (Kd app) for TEBG as determined by Scatchard analysis was 2.0 X 10(-9) M, whereas the Kd app for the trophoblastic binding protein after isoelectric focusing was 1.5 X 10(-10) M. A second binding protein found in both vesicular extracts and mole fluid was shown to have an isoelectric elution value (pH 5.2) similar to TEBG and an Kd app of 1.7 X 10(-9) M DHT, very close to the TEBG value. Apparent equilibration for both proteins with DHT was shown to occur in approximately 4H, and both proteins were shown to be high affinity, low capacity binders. The relative affinities of both proteins for other steroids was found to be similar except for methyltrienolone, which appeared to have a higher affinity for the trophoblastic binding protein.

Androgen-Binding Protein↗
PubMed1980

Trophoblastic disease monitoring: Evaluation of pregnancy-specific beta 1-glycoprotein.

Pregnancy-specific beta 1-glycoprotein (SP1) was evaluated as a potential marker protein for monitoring trophoblastic disease. Four patients with post-molar pregnancy accompanied by spontaneous titer remission and three patients with nonmetastatic trophoblastic disease were found to have regression curves for both human chorionic gonadotropin (hCG) and SP, which closely followed each other. Of three patients with metastatic choriocarcinoma, two were shown to have discordant hCG and SP1 patterns, SP1 in both cases was plateauing or rising while hCG continued to fall. Two other patients are described, one with a spontaneous remission, and one who previously had had choriocarcinoma and was found to have low levels of hCG with higher levels of SP1.

Adolescent↗
PubMed1978

Developmental restrictions on hormone modulated gene transcription. II. Hormone induced interactions of RNA polymerase with chromatin.

Chromatin-bound and soluble RNA polymerase subspecies have been isolated and fractionated by isoelectric focusing at various times (0, 6, 12 and 18 h) following auxin treatment of 4 day (responsive) and 8 day (unresponsive) soybean hypocotyls. Young 4 day seedlings displayed two well defined phases of auxin induced gene transcription. Phase I (6 h) evidenced the selective dissociation of many RNA polymerase subspecies from the chromatin complex which was accompanied by the retention of three class II enzymes. Phase II occurred after 12 h of treatment when the dissociated enzymes including some species which were soluble in the 0 h controls became re-associated with chromatin. These induced RNA polymerases may be responsible for the synthesis of auxin induced RNAs. In contrast, the unresponsive 8 day hypocotyl did not display two phases of auxin induction. Phase one, the dissociation of the chromatin bound enzymes, occurred at 12 h (compared to 6 h for the 4 day seedling) and was not followed by the later translocation of any soluble enzymes towards the chromatin complex. The results support earlier findings suggesting that the developmental "phasing out" of RNA polymerase subspecies limits the hormone induced growth response of this tissue and thus is regarded as an off switch for the transcription of such hormone controlled gene sequences.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1978

Solubilization and developmental distribution of embryonic antigen of the chick red blood cell plasma membrane.

An antigen(s) on the surface of embryonic and newly hatched chick red blood cells was studied with antiserum absorbed with adult red blood cells. Because of the reappearance of the antigen or some cross-reactive antigen during myeloblastosis, attempts at solubilization and characterization of the antigen were pursued. Antigen was solubilized from whole red blood cell lysates or from red blood cell ghosts with 0.01 M Tris:0.1% Nonidet P40, pH 8.0. Antigen was assayed with an enhancement of agglutination assay. Enhancement apparently occurs because of available specific receptors for the antigen on newly hatched chick red blood cells. Antigen was also found to be present in plasma, and both the membrane-derived antigen and the plasma antigen were excluded from Sephadex G-100. Isoelectric focusing of the antigen extract indicated the presence of more than one molecular species with antigenic activity.

Age Factors↗
PubMed1978

A preliminary study of the superoxide dismutase content of some human tumors.

The cell cytosol superoxide dismutase (SODase) content of 46 human tumors was investigated. The extraction procedure of McCord and Fridovich was used with the epinephrine assay of Misra and Fridovich (J. Biol. Chem., 247; 3170-3175, 1975). The purpose of the study was to determine whether SODase could be reliably assayed from small, biopsy-sized pieces of tumor (0.5 to 1.0 g). In most cases it was possible to examined larger masses of tumor, which served as a control of the methodology. In this preliminary study SODase values, calculated from a standard curve derived from purified bovine blood SODase with a specific activity of 2584 units/mg, ranged from as little as 0.23 to as much as 160.5 units/g of tumor. These findings suggested that the procedures used might be feasable on a routine basis to determine the SODase content of tumors and its possible relationship to the radiation sensitivity of the tumors.

Breast Neoplasms↗