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Biomedical subjects

J A Horowitz

Publications and source records attributed to J A Horowitz.

32 records · Page 2Linked to original sources
PubMed1989

Imaging of colorectal carcinoma with radiolabeled antibodies.

Colorectal cancer has been the tumor type most frequently studied with radiolabeled antibodies. Among the various antibodies, a majority of patients with colorectal cancer have received xenogeneic polyclonal or monoclonal antibodies against carcino-embryonic antigen. This review summarizes the current status of colorectal cancer imaging with radiolabeled antibodies, ie, radioimmunodetection (RAID), and examines the published studies involving carcinoembryonic antigen (CEA) antibodies and 17-1A, 19-9, and B72.3, and other monoclonal antibodies. In order to better address the issue of the current and future clinical usefulness of this emerging technology, particular attention is given to the protocols, methods, and results of the published studies. Despite differences in study parameters, antibodies and forms, labels, administration routes and doses, and scanning instruments and methods, it has been found that (1) almost no adverse reactions have been evident; (2) antibody fragments are preferred over whole immunoglobulin G reagents because they achieve higher tumor-to-background ratios earlier, thus reducing or precluding the need for dual-isotope subtraction methods or long delays before imaging; (3) use of antibody fragments, including the monovalent Fab' form, permits imaging with short-lived radionuclides of excellent photon properties, such as 123I and 99mTc; (4) circulating antigens against which the imaging antibody is directed can complex with the injected antibody, but such complexes have not prevented successful RAID; (5) patients with high serum titers of the appropriate antigen target usually have higher rates of positive RAID; (6) patients who are seronegative for the tumor antigen being studied can have positive RAID findings, which can represent the detection of occult lesions; (7) single photon emission computed tomography appears to provide better image resolution than planar scanning; (8) regardless of the sensitivity reported in any particular study, almost all investigators have observed the disclosure of occult neoplasms by RAID; and (9) RAID, a more functional test of usually high specificity, can complement other radiological methods, such as computed tomography scans, which are limited to structural information.

Antibodies, Monoclonal↗
PubMed1988

Interaction of the regulatory subunit of a type II cAMP-dependent protein kinase with mammalian sperm flagellum.

We have reported previously (Horowitz, J. A., Toeg, H., and Orr, G. A. (1984) J. Biol. Chem. 259, 832-838) that most of the type II cAMP-dependent protein kinases in rat sperm are associated with the flagellum. We have now identified flagellar polypeptides which are capable of forming tight complexes with the regulatory subunit of type II cAMP-dependent protein kinase (RII). Flagellar RII-binding polypeptides were identified using an RII overlay/immunoblot procedure and had apparent subunit Mr of 120,000, 80,000, and 57,000 in rat and 120,000 and 57,000 in bovine flagella. RII is released from the flagellum by disulfide reducing agents, e.g. 1 mM dithiothreitol (DTT). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Coomassie Blue staining of the DTT-released material shows that a limited subpopulation of flagellar polypeptides are solubilized by disulfide-reducing agents. Neither tubulin, the dynein ATPase, or any of the RII-binding proteins are released by 1 mM DTT, and thin section electron microscopy revealed that the morphology of the flagellum is unaltered by reducing conditions. Our data established that RII is not linked to the flagellum via a direct disulfide bridge. We propose that RII is released from the flagellum, a highly disulfide cross-linked structure, due to structural changes in the flagellum which disrupts the interaction between RII and its binding proteins.

Animals↗
PubMed1984

Characterization and localization of cAMP-dependent protein kinases in rat caudal epididymal sperm.

We have studied the subcellular localization of type I and type II cAMP-dependent protein kinases in rat caudal epididymal sperm. Our studies indicated that a large fraction of the cAMP-binding activity (approximately 60%), as well as a significant portion of the catalytic activity (approximately 40%), remained associated with insoluble material after the plasma membrane was extracted with 1% Triton X-100. Only 15% of the cAMP-binding activity in sperm was membrane bound. To explore the possibility of a surface location for the membrane-associated cAMP-binding proteins, whole sperm were subjected to proteolysis. Sperm treated with alpha-chymotrypsin lost cAMP-binding activity in cytoplasmic, detergent-soluble, and detergent-resistant fractions. These results demonstrate that alpha-chymotrypsin had access to intracellular locations and to all of the cAMP-binding proteins in sperm. Photoaffinity labeling studies using 8-azido-[32P]cAMP suggest that the regulatory subunit (R) present in the membrane was predominantly RI, while the major species present in the cytoplasm and on detergent-resistant structures was RII. Detergent-resistant sperm structures could be depleted of endogenous catalytic activity by the addition of cAMP, and cAMP-dependent kinase activity could be subsequently regained by the addition of bovine heart catalytic subunits. Separation of head and tailpieces showed that the detergent-resistant regulatory subunits were almost exclusively located on the tailpiece. This finding is consistent with the involvement of cAMP-dependent protein kinases in sperm motility.

Adenosine Monophosphate↗
PubMed1977

Mothering.

One can conclude that mothering as an essential component of family life will not be abolished. Attention to the skill and personal dimensions of the mothering role will insure the maintenance and growth of this valuable institution. The time has come for nurses to design strategies that liberate mothers from a restrictive position while promoting effective mothering, personal growth, and societal change.

Child↗
PubMedDate not supplied

Mother's perceptions of postpartum stress and satisfaction.

OBJECTIVE: To examine mothers' postpartum perceptions of stress and satisfaction. DESIGN: Methodologic triangulation with quantitative and qualitative data in a nonexperimental design. PARTICIPANTS AND SETTING: A convenience sample of 95 women was obtained during normally scheduled postpartum appointments at a health maintenance organization. MAIN OUTCOME MEASURES: The self-administered questionnaire included the Mothers' Information Tool (MIT), What Being the Parent of a Baby Is Like (WPL-R), and the Brief Symptom Inventory (BSI). Open-ended MIT items revealed mothers' perceptions of stress and satisfaction. The WPL-R provided maternal satisfaction scores, and the BSI yielded Global Stress Index scores. RESULTS: Content analysis identified the following categories: Roles, Tasks, Resources, and Relationships. Subcategories identified as areas of stress were Work/School, Sleep/Rest, Adjustment/Own Needs, Health/Body Image, Organization of Life, Child Care, Day Care, Housework, Future Challenges, Finances, Housing, Time, Partner, and Family. Subcategories identified as areas of satisfaction were Participating in Relationships, Sharing the Future, Being Proud to Be a Mother, Enjoying a Healthy Baby, and Caring for a Child. Levels of stress and satisfaction of mothers who scored high and low on quantitative measures were compared. CONCLUSION: The outcomes contribute to the knowledge concerning postpartum women's perceptions of the mothering experience and suggest approaches to nursing assessment and intervention to prevent postpartum adjustment difficulties.

Adolescent↗
PubMedDate not supplied

Identification of symptoms of postpartum depression: linking research to practice.

This paper presents a research approach for identification of symptoms of postpartum depression that could be adapted for use in practice settings. Women (n = 95) who had recently given birth completed a self-administered questionnaire at a health center at the time of their regularly scheduled postpartum visit. The questionnaire was composed of The Mothers' Information Tool to obtain demographic data, personal history, and information about the woman's birth and postpartum experience and the Depression Adjective Check Lists (DACL) and Brief Symptom Inventory (BSI) to assess symptoms suggestive of postpartum depression. Follow-up assessment of women whose scores were elevated on the DACL or BSI provided confirmation of symptoms and opportunity for additional evaluation and treatment of postpartum depression when indicated. The authors conclude that paper-and-pencil instruments could be used effectively in clinical practice to identify depressive symptoms among postpartum women.

Clinical Medicine↗