Search PubMed⌕ Search

Biomedical subjects

D Doyle

Publications and source records attributed to D Doyle.

At least 109 records · Page 6Linked to original sources
PubMed1987

Isolation of domains of the plasma membrane of hepatocytes.

Several recent studies have demonstrated the ability of techniques based on immunoadsorption to selectively isolate specialized subregions of membranes, termed domains, which are derived from a larger more complex parent membrane like the plasma membrane. The immunoadsorbent is directed against a specific antigen that resides exclusively or predominantly in the membrane domain to be isolated. Thus, a monospecific antibody to the domain-specific antigen is required. In the present study we developed a method employing a modified immunoblotting strategy which could utilize polyspecific antibodies to isolate membrane vesicles derived from a specific membrane domain of the hepatocyte plasma membrane. We also used specific cell surface labeling of the hepatocyte plasma membrane by lactoperoxidase-catalyzed iodination at 4 degrees C and preparation of different sized vesicles by sonication to facilitate isolation of the specific domain. For this study, polyspecific antisera were raised in goats against a membrane fraction, denoted N2u, which is enriched in bile canalicular proteins. This antiserum recognizes, among other antigens, a 110,000 Mr polypeptide previously shown to be localized in the bile canaliculus (J. Cook et al. (1983) J. Cell. Biol. 97, 1823-1833). A monospecific antiserum was raised in rabbits against the rat hepatocyte asialoglycoprotein receptor, a sinusoidal domain-specific set of glycoproteins whose major form has a Mr of 43,000. These antisera were each coupled indirectly to different pieces of nitrocellulose by the immunoblotting protocol and were used to isolate membrane vesicles from a crude extract of liver plasma membrane prepared by sonication. The ratio of iodinated asialoglycoprotein receptor to the 110,000 Mr polypeptide in vesicles isolated by the affinity nitrocellulose immunoadsorbent method indicate a 10- to 15-fold enrichment of sinusoidal-derived vesicles relative to bile canalicular-derived membrane vesicles. These results show that the affinity nitrocellulose immunoadsorbent method can be used to isolate domain-specific vesicles. Further, the affinity immunoadsorbent method described here for the isolation of domains of the plasma membrane is an integrative one allowing isolation of vesicles present in relatively small concentration in crude cell extracts and it requires minimal ultracentrifugation time.

Affinity Labels↗
PubMed1987

cDNA cloning for a bile canaliculus domain-specific membrane glycoprotein of rat hepatocytes.

Hepatocytes are polarized cells with distinct sinusoidal, bile canalicular, and basolateral plasma membrane domains. Each domain contains proteins that are specific for it. We have isolated three cDNA clones encoding a rat liver bile canaliculus domain-specific glycoprotein with Mr 110,000 (gp110) by immunologically screening a rat kidney lambda gt11 cDNA library with a rabbit polyclonal antiserum directed against purified gp110. The authenticity of these clones was verified as follows. (i) The antiserum recognizes specifically isopropyl beta-D-thiogalactoside-induced fusion proteins on electrophoretic transfer blots of total lysogen lysates containing these cDNA clones. (ii) Antibodies epitope-selected by these clones are able to interact with gp110 on electrophoretic transfer blots. (iii) The amino acid sequencing derived from the DNA sequence was confirmed by amino acid sequencing of a tryptic peptide of gp110. Rescreening of the same library with the cDNA clones identified a full-length cDNA clone for this glycoprotein. Sequence analysis indicates that the N-linked carbohydrate chains are concentrated on the N-terminal part of this highly glycosylated protein.

Amino Acid Sequence↗
PubMed1987

Magnetic resonance imaging in the management of resistant focal epilepsy: pathological case report and experience of 12 cases.

Clinical improvement in epilepsy following temporal lobectomy is more often obtained when an abnormality is found on subsequent histological examination. Pre-operative MRI demonstrated an abnormal signal in the temporal lobe of a patient with pathologically proven mesial temporal sclerosis with microvascular anomaly. MRI may therefore be helpful in the selection of patients for temporal lobectomy. MRI findings of 12 patients with resistant focal epilepsy are reviewed. A wide range of T1 and T2 weighting is suggested to maximise selection of patients.

Adult↗
PubMed1987

Rhino-orbital-cerebral mucormycosis--a clinico-pathological report of two cases.

Rhino-orbital-cerebral mucormycosis is an acute fungal infection of the oropharynx, paranasal sinuses, orbit and intracranial structures. It is rare, occurring mainly in diabetics in ketoacidosis. The clinical presentation is highly suggestive of the diagnosis. Current treatment has resulted in a greatly improved prognosis for survival and clinical awareness of this disease is important for early initiation of treatment with optimal effect. A clinico-pathological report of two cases is presented.

Adult↗
PubMed1987

Lymphatic system of the thyroid gland in the rat.

Intraglandular thyroid lymph vessels in the rat were studied by qualitative and quantitative analyses in order to obtain information regarding their structure, distribution, relationships, and possible mechanisms of lymph formation. Ultrastructurally, the lymphatic vessels were similar to those described in other organs. The volume density of the lymphatic vessels was 0.007, the profile density 5.68 mm2 and the maximum diameter 17.87 nm. Ultrastructurally, visible transport pathways across the vessels appear to be represented by intracytoplasmic vesicles and channels between endothelial cells. The mean maximum diameter of the vesicles was 96 nm and they occupied 6.9% of the cytoplasm. They were equally distributed between luminal, abluminal, and intracytoplasmic positions. Open junctions (greater than 30 nm) were not seen between endothelial cells, but dilations along part of the length of interdigitating and overlapping contacts were frequent. It was concluded that the mechanism of lymph formation in the thyroid is similar to that in the kidney and liver, but differs from that in the dermis or diaphragm. However, the volume density of the vesicles of the thyroid was twice that of the liver and more than twice that of the kidney. This finding is consistent with an increase in transendothelial vesicular transport of macromolecules.

Animals↗
PubMed1986

The Medtronic-Hall cardiac valve: 7 1/2 years' clinical experience.

Clinical information on the Medtronic-Hall valve prosthesis was obtained by reviewing the records of 379 patients, 164 of whom had aortic valve replacement (AVR), 163 of whom had mitral valve replacement (MVR), and 52 of whom had double valve replacement over 90 months (1,225 patient-years) (mean follow-up, 42.01 +/- 1.3 months [+/- standard error]). Mean age was 53.8 +/- 12 years. One hundred ninety-three patients (50.9%) had some type of concomitant operation, such as tricuspid annuloplasty, coronary artery bypass grafting, or resection of ascending aortic aneurysm. Ninety-one percent were in New York Heart Association (NYHA) Functional Class III or IV preoperatively. Early mortality and late mortality were 7.7% (29 patients) and 13.5% (51 patients), respectively. The actuarial survival at 7 1/2 years was 74.1 +/- 2.7% for the total group and 69.0 +/- 4.5% for those having AVR, 81.0 +/- 3.2% for those having MVR, and 67.0 +/- 8.9% for those having double valve replacement. All patients but 2 were maintained on a regimen of chronic anticoagulation with warfarin sodium. Twenty-six thromboembolic episodes occurred (2.1/100 patient-years): 13 after MVR (2.3/100 patient-years), 11 after AVR (2.1/100 patient-years), and 2 after double valve replacement (1.4/100 patient-years). Four thromboembolic episodes were fatal; no valve thrombosis occurred. There were no structural failures. Of the 350 late survivors, 92% were in NYHA Functional Classes I and II. Total valve-related complications have been minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1986

Necropsy study of mountaineering accidents in Scotland.

One hundred and twenty one people died in mountaineering accidents in Scotland between July 1978 and December 1983. Necropsies were carried out on 42, which form the basis of this report. In 21 cases head injury was major fatality factor, but in 11 of these there were also serious chest injuries. Focal brain damage (haematomas, contusions, or lacerations) was more common (n = 21) than diffuse brain damage (n = 18). Over half of the victims with severe head injury had few other injuries and would probably have survived had the head injury been prevented. Spinal injuries usually occurred with other major injuries. Chest injuries were common, being serious in 18 cases, but abdominal injuries were uncommon. Four climbers with only minor injuries died of hypothermia.

Abdominal Injuries↗
PubMed1986

Deep intracerebral (basal ganglia) haematomas in fatal non-missile head injury in man.

Deep intracerebral (basal ganglia) haematomas were found post mortem in 63 of 635 fatal non-missile head injuries. In patients with a basal ganglia haematoma, contusions were more severe, there was a reduced incidence of a lucid interval, and there was an increased incidence of road traffic accidents, gliding contusions and diffuse axonal injury than in patients without this type of haematoma. Intracranial haematoma is usually thought to be a secondary event, that is a complication of the original injury, but these results suggest that a deep intracerebral haematoma is a primary event. If a deep intracerebral haematoma is identified on an early CT scan it is likely that the patient has sustained severe diffuse brain damage at the time of injury. In the majority of head injuries damage to blood vessels or axons predominates. In patients with a traumatic deep intracerebral haematoma, it would appear that the deceleration/acceleration forces are such that both axons and blood vessels within the brain are damaged at the time of injury.

Adolescent↗
PubMed1986

Life-threatening respiratory failure due to a previously undescribed myopathy.

The case of a young man with a previously undescribed myopathy associated with polydactyly is reported. Although both limb girdles were affected, the major effect of the disease was upon the respiratory muscles leading to his presentation with life-threatening respiratory failure. A further feature was pronounced stiffness of the vertebral column and limb girdles, similar in some respects to the 'rigid spine syndrome'. Muscle biopsy appearances were unique but showed some similarities to both nemaline myopathy and myotonic dystrophy. Ventilatory assistance at night using a rocking bed led to a marked improvement and has enabled the patient to return to full-time employment.

Adult↗
PubMed1986

Osteoarthritis.

Explore the source record for details and available documents.

Female↗
PubMed1986

Gliding contusions in nonmissile head injury in humans.

"Gliding" contusions, ie, hemorrhagic lesions in the parasagittal white matter, were analyzed in 434 fatal nonmissile head injuries in humans. It is concluded that gliding contusions are a type of diffuse brain damage occurring at the moment of injury. Gliding contusions are significantly associated with road-traffic accidents, with the absence of a skull fracture or a "lucid interval," and with the presence of diffuse axonal injury and deep hemispheric traumatic hematomas.

Accidents, Traffic↗
PubMed1985

N-Linked oligosaccharides of the H-2Dk histocompatibility protein heavy chain influence its transport and cellular distribution.

The H-2K and H-2D proteins encoded by the K and D region of the major histocompatibility complex of the mouse were isolated by immunoprecipitation with specific antisera and resolved by two-dimensional gel electrophoresis. Of these two polypeptides, the H-2Dk glycoproteins isolated from macrophages of C3H/HeHa mice exhibit distinct cell surface and cytoplasmic forms although they share a strong degree of homology in the polypeptide backbone. Structurally they differ in their oligosaccharide structures. The structure of the oligosaccharides on the intracellular forms is of the high mannose type while the same structures on the cell surface forms are of the complex type. In the absence of all three oligosaccharide side chains, the unglycosylated polypeptides are expressed on the cell surface. In contrast, polypeptides containing one, two, or all three oligosaccharide side chains of the high mannose type are not transported to the cell surface. Cell surface expression of these glycoproteins requires processing of the oligosaccharide side chains from the high mannose form to the complex type. However, not all oligosaccharide antennae have to be terminally modified since H-2Dk glycoproteins synthesized in the presence of oligosaccharide-processing enzyme inhibitors such as swainsonine or monensin are also transported to the cell surface. H-2Dk glycoproteins containing oligosaccharide structures of the complex type but lacking terminal sialic acids are found on the cell surface, suggesting that sialylation is not required for transport. These results indicate that the oligosaccharide structures of the H-2Dk glycoproteins act to influence their cellular distribution.

Animals↗
PubMed1985

Turnover of plasma membrane proteins in rat hepatoma cells and primary cultures of rat hepatocytes.

The half-lives of turnover of plasma membrane proteins in rat hepatoma tissue, culture cells, and in primary cultures of rat hepatocytes have been analyzed after resolution by two-dimensional gel electrophoresis. Cell membranes were externally labeled via iodination catalyzed by lactoperoxidase and glucose oxidase. A bimodal pattern of turnover was found for the externally oriented plasma membrane proteins of rat hepatoma cells. Three glycoproteins analyzed in these cells had an average t 1/2 of 22 h while eight proteins which did not bind to concanavalin A had an average t 1/2 of 80 h. In contrast, more heterogeneous rates of turnover were found for the externally oriented plasma membrane proteins of primary cultures of hepatocytes. Most, if not all, of the membrane proteins accessible to iodination in these cells were glycoproteins. Among the glycoproteins resolved by two-dimensional polyacrylamide electrophoresis, the receptors for asialoglycoproteins had the shortest half-lives (18 h). Other glycoproteins, mostly with higher molecular weights and different isoelectric points, showed a spectrum of half-lives ranging from 16 to 99 h. The turnover rates of membrane proteins of primary cultures of rat hepatocytes were also determined with [3H]- and [35S]methionine labeling of cells. Heterogeneous rates of turnover again were found among the labeled glycoproteins and nonglycoproteins. Among the 10 glycoproteins individually analyzed, the half-lives range from 17 to 67 h. Among the 21 proteins which do not bind to concanavalin A, the half-lives range from 18 h to more than 100 h. Three proteins analyzed showed an apparent biphasic pattern of turnover, having a fast phase with a half-life of 4-6 h and a slow phase with a half-life of 15-29 h. Several nonglycoproteins, including clathrin and actin associated with membrane vesicles had extremely long half-lives. The more than 5-fold difference in the half-life between clathrin and the receptors for asialoglycoproteins, which coexist in coated pits indicates that intrinsic proteins of the coated pits turn over at a different rate than peripheral components.

Actins↗