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Biomedical subjects

K Hawkins

Publications and source records attributed to K Hawkins.

65 records · Page 4Linked to original sources
PubMed1979

Differences in localization of insulin receptors and adenylate cyclase in the human placenta.

The interactions of hormones with plasma membranes in the human placenta were characterized for specific fetal and maternal components. The microvillus brush border membrane, which is exposed to maternal blood in the intervillous space, was markedly enriched in specific insulin receptors but contained no hormone-sensitive adenylate cyclase. On the other hand, a basal plasma membrane fraction, which is presumably exposed more directly to fetal hormones, contained adenylate cyclase which was sensitive to prostaglandins, epinephrine, and fluoride but was not enriched in insulin receptors or other brush border markers. This study demonstrates separate fetal and maternal aspects of placental-hormone interactions. This separation and the relative impermeability of the placenta to hormones may allow for independent maternal and fetal components of the interaction of hormones with the placenta.

Adenylyl Cyclases↗
PubMed1979

Humoral factor that specifically regulates factor X levels in rabbits (coagulopoietin-X).

A heat-stable humoral substance (coagulopoietin-X) is present in rabbits partially depleted of Factor X, which is capable of raising Factor X levels when injected into recipient rabbits. Rabbits were partially depleted of Factor X by slow infusion of a globulin fraction of goat anti-rabbit Factor X antibody. This resulted in the reduction of Factor X to 40--50% of normal at 1 h and 60--70% of normal at 6 h. No effect was noted on levels of Factors II, V, or VII. Plasma from these animals, when injected into 10 recipients, specifically raised Factor X levels when measured by four different assay: one-stage assay with bovine VII- and X-deficient plasma and Russell's viper venom; one-stage assay with human X-deficient plasma and thromboplastin; chromogenic substrate assay with Russell's viper venom; and an immunologic assay (Laurell technique). No rise was noted in two control experiments in which normal plasma was injected into recipient rabbits from 2 rabbits injected with a globulin fraction of normal goat serum, nor in 12 rabbits injected with plasma from normal rabbits, nor in 5 rabbits injected with boiled plasma from normal rabbits. The rise in biologic activity of 120--150% of base line was significantly greater than the rise in immunologic activity of 114--117% of base line (P less than 0.05) on 3 different days, suggesting the production of a molecule with greater specific activity rather than increased protein synthesis.

Animals↗
PubMed1975

Homonymous hemianopia in multiple sclerosis. With report of bilateral case.

A patient with multiple sclerosis and bilateral retrochiasmal visual field defects is reported. Homonymous field defects are rare in multiple sclerosis despite the frequency of pathological involvement of the retrochiasmal visual pathways. A higher incidence might be found with a higher index of suspicion and careful visual field testing with qualitative confrontation technique. Other reasons for the infrequent clinical detection of retrochiasmal lesions are considered. Such lesions may exist without demonstrable defect. This may be explained by anatomical factors, for example, fibre arrangement, or physiological factors, such as, geniculate or retrogeniculate integration. Lesions producing demonstrable defects may be asymptomatic because they: affect only the peripheral field, are small scotomas that do not impair visual acuity, affect only one eye, or occur late in the course of disease when masked by optic nerve involvement.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Adolescents' perceptions of print cigarette advertising: a case for counteradvertising.

Cigarette smoking is a major preventable cause of serious chronic disease. The majority of smokers begin smoking during their adolescent years. Print cigarette advertising plays an influential role in encouraging young people to smoke. Eight hundred and forty-three middle/junior high-school-aged students from a large midwestern metropolitan area participated in this study of adolescents' recognition of and belief in messages associated with print cigarette advertising. Results indicated no significant difference between smokers and nonsmokers in their recognition of messages associated with print cigarette advertising. However, smokers and nonsmokers differed significantly in the degree to which they believed the messages communicated by print cigarette advertising. Consistent with social cognitive theory, students who smoke at least occasionally were more likely to believe messages conveyed by print cigarette ads than were students who had never smoked. Implications of these findings for research and practice are discussed, including specification of guidelines for effective counteradvertising.

Adolescent↗
PubMedDate not supplied

Peripherally inserted central catheters: placement and use in a family practice hospital.

BACKGROUND: The peripherally inserted central catheter (PICC) is increasingly used in protracted intravenous therapy. The device has several advantages for family practice, but its use has been chiefly described in nursing and interventional radiology literature. We investigated the use of the PICC in a family practice teaching hospital. METHODS: Forty PICCs were inserted from 1993 to 1995 in 29 patients. Available records and radiographs were reviewed for indication, nature of placement attempts, indwelling time, PICC role in therapy, and attendant complications. RESULTS: Successful placement was achieved in 95 percent of instances requiring PICC use. Fluoroscopically guided placement, usually without venography, was found to be preferable to unguided bedside placement. In a few cases in which PICCs were placed, no other access was subsequently required to complete therapy. Few clinically serious complications were encountered. Most complications were related to placement at bedside. CONCLUSIONS: Our experience supports the PICC as a minimally invasive, economical alternative for protracted intravenous therapy. Fluoroscopically guided placement was found preferable to unguided bedside placement. Physicians ordering or placing PICCs should understand fully how to assess placement.

Adolescent↗