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Biomedical subjects

C Watts

Publications and source records attributed to C Watts.

At least 37 records · Page 2Linked to original sources
PubMed1990

High-order multifetal gestation--management and outcome.

During the period 1975-1989, 11 high-order (quadruplet or more) multifetal gestations reaching the second trimester were treated in our department. All pregnancies resulted from ovulation induction therapy. Premature contractions occurred in all cases. Two women delivered stillborn quadruplets vaginally at 25 and 26 weeks' gestation. Nine women had cesarean deliveries at 28-35 weeks; one fetus was stillborn and two of the 39 live-born infants died. Twenty-nine (74%) weighed less than 1500 g and 16 (41%) were below the tenth percentile for gestational age. Thirty infants have been followed for at least 2 years, corrected for gestational age; 21 (70%) are developing normally, two are severely handicapped with both cerebral palsy and mental retardation, four have mild motor delay, and three have mild motor and mental delay.

Adult↗
PubMed1989

Epitope-directed processing of specific antigen by B lymphocytes.

Proteolytic processing of specific antigen was studied using Epstein Barr virus transformed B-lymphoblastoid cells expressing membrane IgG against tetanus toxin. As previously reported (Watts, C., and H.W. Davidson. 1988. EMBO (Eur. Mol. Biol. Organ.) J. 7:1937-1945), receptor-mediated endocytosis of monovalent antigen bound at 0 degrees C began immediately upon shifting the cells to 37 degrees C. In contrast, degradation of antigen, assessed either by the release of acid-soluble radiolabel into the incubation medium, or by SDS-PAGE analysis of total cell-associated antigen, proceeded after a lag of 10-20 min. Degradation was abolished by exposure of the cells to metabolic inhibitors, or by incubation at 20 degrees C, and inhibited in a dose-dependent fashion by chloroquine and by the lysosomal protease inhibitors leupeptin, E-64, and pepstatin A. Analysis of the cell-associated radiolabel by SDS-PAGE and autoradiography after incubations at 37 degrees C revealed the time-dependent generation of distinct antigen fragments. Virtually quantitative immunoprecipitation of these fragments was obtained using a monoclonal anti-human IgG antibody, indicating that the antigen/mIg complex is the initial substrate for processing. We show that the pattern of fragmentation observed varies from one B cell line to another (a) depending on the epitope through which the antigen is bound and endocytosed and (b) depending on whether additional epitopes in the antigen are complexed with anti-tetanus Fabs. The implications of these results for the presentation of major histocompatibility complex restricted antigen fragments, and for intracellular trafficking of ligand/receptor complexes are discussed.

Antigen-Presenting Cells↗
PubMed1989

Distinct endocytotic pathways in epidermal growth factor-stimulated human carcinoma A431 cells.

Addition of EGF to human epidermoid carcinoma A431 cells increases the rate of fluid-phase pinocytosis 6-10-fold as measured by horseradish peroxidase uptake (Haigler, H.T., J. A. McKanna, and S. Cohen. 1979. J. Cell Biol. 83:82-90). We show here that in the absence of extracellular Na+ or in the presence of amiloride the stimulation of pinocytosis by EGF is substantially reduced. Amiloride had no effect on the endocytosis of EGF itself or of transferrin, demonstrating that the receptor-mediated endocytotic pathway operated normally under conditions that blocked stimulated pinocytosis. Amiloride blocked EGF-stimulated pinocytosis in both HCO3(-)-containing and HCO3(-)-free media. The EGF-stimulated pinocytotic activity can frequently be localized to areas of the cell where membrane spreading and ruffling are taking place. These results demonstrate that (a) EGF induces a distinct amiloride-sensitive endocytotic pathway on A431 cells; (b) occupied EGF receptors do not utilize this pathway for their own entry; (c) endocytosis of occupied EGF receptors is not in itself sufficient to stimulate pinocytosis.

Amiloride↗
PubMed1986

Isolation and expression of cDNA clones for a rat liver asialoglycoprotein receptor.

cDNA clones for the major rat liver asialoglycoprotein (ASGP) receptor were isolated from a phage lambda gt11 library using synthetic oligonucleotide probes corresponding to two regions of the protein sequence. The longest clone obtained encoded all but the first 11 codons of the receptor. The cDNA was completed with synthetic oligonucleotides and was used to direct the synthesis of mRNA for the receptor in vitro. Subsequent translation in a wheat germ lysate produced authentic ASGP receptor which assembled correctly into microsomal membranes.

Animals↗
PubMed1985

Rapid endocytosis of the transferrin receptor in the absence of bound transferrin.

The rate of endocytosis of transferrin receptors, occupied or unoccupied with transferrin, was measured on the cell line K562. At 37 degrees C, receptors, radioiodinated on the cell surface at 4 degrees C, were internalized equally rapidly in the presence or absence of transferrin. In both cases, 50% of the labeled receptors became resistant to externally added trypsin in 5 min. An antitransferrin antibody was used to show directly that the receptors had entered the cells without bound transferrin. The distribution of the receptors on the cell surface was revealed by antibody and protein A-gold staining after prolonged incubation in the presence or absence of transferrin. The receptors were concentrated in coated pits under both conditions. The data suggest that endocytosis of transferrin receptors is not "triggered" by ligand binding and raise the possibility that ligand-induced down-regulation of surface receptors may not occur by this mechanism. Instead receptors may be recognized as being ligand-occupied, not at the cell surface, but at some other site in the recycling pathway such as the endosome.

Cells, Cultured↗
PubMed1979

Computed tomography and intracranial aspergillosis.

A case of aspergillosis of the central nervous system with multiple granulomas examined by computed tomography is reported. The findings are those of chronic mass lesions with and without calcium deposits. An associated cystic configuration probably is not specific for aspergillomas.

Adolescent↗
PubMed1978

Protein and lipid components of the pigeon erythrocyte membrane.

The plasma membrane of the nucleated pigeon erythrocyte was isolated by a method that is simple, reproducible and minimally disruptive, the final preparation consisting of whole cell 'ghosts', recovered at over 40% yield. Alternative methods, which yield membrane fragments, were also tested and some of their possible disadvantages demonstrated. Analysis of the protein components of the isolated membranes by gel elctrophoresis in the presence of sodium dodecyl sulphate revealed that their composition is very similar to that of the proteins of human erythrocyte membranes. However, two major proteins are unique to the nucleated cell membrane; these have apparent mol.wts. of 97000 and 57000. Also, the bands designated 4.2 (74500 mol.wt.) and 6 (35000 mol wt.) by Steck [(1974) J. Cell Biol. 62, 1-19] for the human cell membrane are absent from pigon cell membrane. Glycosylated membrane proteins could not be detected in gels stained with the periodate-Schiff-base procedure. Analysis of membrane phospholipids revealed the same components known to be present in mammalian erythrocytes, though in different proportions. These findings are discussed in the light of known physiological and biochemical differences between avian and mature mammalian erythrocytes.

Animals↗
PubMed1977

Transsphenoidal microsurgery for selective removal of functional pituitary microadenomas.

The transphenoidal approach to the pituitary gland is emerging as the safest and most efficacious procedure for the management of pituitary tumors. With the aid of the microscope large tumors producing visual symptoms can be removed and microadenomata producing only signs and symptoms of endocrinopathies can be safely and adequately approached. The procedure is described in this report. The results of its use in 29 patients with selected illustrative case reports are described.

Acromegaly↗
PubMed1977

Cerebral revascularization for transient ischemic attacks.

Thirty-one patients with cerebral transient ischemic, attacks and ipsilateral internal carotid artery occlusion without contralateral internal carotid artery occlusion or stenosis were treated with a surgical anastomosis between a superficial temporal artery and a cortical branch of the middle cerebral artery of the symptomatic hemisphere. The anastomosis was successful in 28 patients. Recurrent transient ischemic attacks were abolished in 23 patients and reduced in three. Two patients, one with a patent anastomosis, had strokes during the follow-up period. Of seven patients who refused the operation, two had strokes, two noted a reduction of transient ischemic attacks, two noted no change, and one became asymptomatic.

Adult↗
PubMed1977

Disseminated intravascular coagulation.

The diagnosis of disseminated intravascular coagulation associated with intracranial pathology is discussed. This pathological entity is characterized by a diffuse bleeding diathesis. Laboratory studies suggest a consumption of all clotting and fibrinolytic factors with an elevation of fibrin split products as a sign of the fibrinolytic activity. The treatment consists of the administration of packed platelets and fresh frozen plasma to replace the consumed coagulation factors. Heparinization is recommended early to prevent further consumption of coagulation factors and epsilon-aminocaproic acid is recommended later after acute fibrinolysis is diagnosed. Constant coaguloanalytic monitoring is necessary. Although the etiology with massive injury to brain tissue is possibly secondary to autotransfusion of brain tissue thromboplastin, other causes such as hypotension, anoxia, acidosis and hemolysis must be considered.

Blood Coagulation Tests↗