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Biomedical subjects

B Burke

Publications and source records attributed to B Burke.

At least 127 records · Page 7Linked to original sources
PubMed1984

Microinjection of mRNA coding for an anti-Golgi antibody inhibits intracellular transport of a viral membrane protein.

Messenger RNA was prepared from a hybridoma cell line secreting a monoclonal antibody (53FC3) directed against a luminal epitope of a Golgi membrane protein (Mr = 135 kd) found in rodent cells. When this mRNA was microinjected into the cytoplasm of BHK cells, mouse IgG was seen to accumulate in the Golgi complex after 5-6 hr of incubation. No accumulation was seen in 3T3 cells which lack the epitope recognized by 53FC3. When microinjected BHK cells were infected with vesicular stomatitis virus, surface expression of the viral G protein was considerably reduced when compared with neighboring noninjected cells.

Animals↗
PubMed1984

Endocrine pancreas in cystic fibrosis: an immunohistochemical study.

The pancreases of 17 patients who had cystic fibrosis with and without diabetes mellitus were evaluated at autopsy by routine staining and immunohistochemical methods for insulin, glucagon, somatostatin, and pancreatic polypeptide. Qualitative assessment of the number of islets of Langerhans and the degrees of exocrine pancreatic atrophy, fibrosis, and fat replacement was made for each pancreas. Quantitative assessment of islet composition was performed in 15 of the 17 based on the immunochemical reactivity of each cell type. Nondiabetic patients with cystic fibrosis in the latter part of the first decade of life have classic fibrocystic changes of the pancreas, with some persisting exocrine tissue, islets that appear normal, and prominent nesidioblastosis. The latter process may protect these patients from glucose intolerance. Young adult diabetic patients with cystic fibrosis have total loss of exocrine pancreas with fat replacement, lack of nesidioblastosis, a qualitative decrease in the number of islets, fibrosis of and amyloid deposits in islets, decreased numbers of insulin-containing cells in each islet, and atrophy of islet cells, probably resulting from progressive ischemia. Although the potential exists for an increasing incidence of diabetes mellitus in patients with cystic fibrosis as their life spans increase, individual variation occurs in this disease.

Adult↗
PubMed1984

Stimulated release of histamine by a rat mast cell line is inhibited during mitosis.

Stimulated histamine release was depressed at least tenfold in mitotic 2H3 rat basophilic cells when compared with interphase cells even though both contained comparable amounts of histamine. Antigen stimulation of IgE-sensitized interphase cells initiated an influx of Ca2+ that preceded secretion of histamine and a similar Ca2+ influx occurred in stimulated mitotic cells. This strongly suggests that during mitosis there is a dramatic inhibition of one or more of the steps on the pathway leading from elevated intracellular Ca2+ to the fusion of secretory granules with the plasma membrane.

Animals↗
PubMed1983

A monoclonal antibody which recognises each of the nuclear lamin polypeptides in mammalian cells.

A monoclonal IgM has been characterised which recognises the nuclear lamins in all mammalian cells tested. In immunoblotting experiments using both one- and two-dimensional gels it recognises lamins A, B and C. The common antigenic determinant lies on a proteolytic fragment of 46,000 daltons which can be generated from each lamin polypeptide by treatment with chymotrypsin. In immunofluorescence experiments on whole cells and thin frozen sections, the antibody labelled only the nuclear envelope and not the nuclear interior. During mitosis, labelling was found dispersed throughout the cell cytoplasm. By immunoelectron microscopy using the antibody and protein A-gold, only the nucleoplasmic side of the nuclear envelope (the nuclear lamina) was labelled, but there was no labelling of the nuclear pores.

Animals↗
PubMed1983

Localisation of 5'-nucleotidase in a rat liver cell line using a monoclonal antibody and indirect immunofluorescent labelling.

A new method of labelling anti-IgG with rhodamine while protecting the IgG binding site is described. Indirect immunofluorescence of the ectoenzyme 5'-nucleotidase using a monoclonal antibody shows that it has a punctate distribution over the whole cell surface of a cultured rat liver cell line. The density of fluorescent spots representing the surface localisation of 5'-nucleotidase and of clathrin-coated pits was analysed by a computerised counting technique. The cell surface localisation of 5'-nucleotidase differs from clathrin-coated pits and microvilli. 5'-Nucleotidase within the cell is not uniquely associated with any clearly defined organelle.

5'-Nucleotidase↗
PubMed1983

Experimental IgA nephropathy in bile duct ligated rats.

Polymeric IgA and polymeric IgA-containing immune complexes are transported from blood to bile through hepatocyte-bound secretory component. In order to investigate interruption of this transport and its effect on the glomerulus, Sprague-Dawley rats underwent bile duct ligation. Renal tissue obtained at the time of sacrifice was stained by immunofluorescent techniques with antibodies to IgG, IgM, and IgA, and secretory component (SC) and C3. A progressive selective increase in the staining intensity of the glomerular mesangium was observed for IgA, C3, and SC in bile duct ligated rats. These changes were paralleled by a rise in serum IgA and C3. These findings are consistent with the view that glomerular deposition of IgA, C3, and SC in bile duct ligated rats may result from impairment of normal handling of polymeric IgA and polymeric IgA-containing immune complexes.

Animals↗
PubMed1983

Expression of Semliki Forest virus proteins from cloned complementary DNA. I. The fusion activity of the spike glycoprotein.

A complementary (cDNA) molecule encoding the structural proteins of Semliki Forest virus (SFV) has been inserted into a Simian virus 40-derived eucaryotic expression vector lacking introns. Introduction of the recombinant DNA into nuclei of baby hamster kidney cells results in the synthesis of authentic SFV membrane glycoproteins E1 and E2. The glycoproteins are both transported to the cell surface and induce cell-cell fusion after a brief treatment of the cells with low pH medium. The pH dependence of the fusion reaction was the same as that induced by virus particles (White, J., J. Kartenbeck, and A. Helenius, 1980, J. Cell Biol., 89:674-679). Transfection of cells with another recombinant DNA molecule in which the SFV cDNA is engineered into the same expression vector including an intron has been shown before to result in the expression of only the E2 protein on the cell surface, whereas the E1 protein is trapped in the rough endoplasmic reticulum (Kondor-Koch, C., H. Riedel, K. Söderberg, and H. Garoff, 1982, Proc. Natl. Acad. Sci. USA, 79:4525-4529). Such cells do not exhibit pH-dependent polykaryon formation, suggesting that the E1 protein is necessary for fusion activity. Immunoblotting experiments show that the RER-trapped E1 protein expressed from the DNA construction with an intron has a smaller apparent molecular weight than authentic E1, and that is has lost its amphipathic characteristics.

Animals↗
PubMed1983

Expression of Semliki Forest virus proteins from cloned complementary DNA. II. The membrane-spanning glycoprotein E2 is transported to the cell surface without its normal cytoplasmic domain.

The E2 protein (422 amino acid residues long) of Semliki Forest virus is a spanning membrane protein which is made in the rough endoplasmic reticulum of the infected cell and transported to the cell surface. The cytoplasmic domain of this protein comprises 31 amino acid residues. We introduced deletions of various sizes into the gene region encoding this part of the protein molecule and analyzed the transport behavior of the mutant proteins. The deletions were made using exonuclease digestions of cloned cDNA encoding the E2 protein. When the mutated DNA molecules, engineered into an expression vector, were introduced into nuclei of baby hamster kidney 21 cells, membrane proteins with cytoplasmic deletions were expressed and routed to the cell surface in the same way as the wild-type protein. This suggests that the cytoplasmic domain of the E2 protein does not carry information that is needed for its transport from the rough endoplasmic reticulum to the cell surface.

Amino Acid Sequence↗
PubMed1983

Newly synthesized G protein of vesicular stomatitis virus is not transported to the cell surface during mitosis.

Indirect immunofluorescence, immunoelectron microscopy, and digestion by protease were used to study intracellular transport of the G protein of vesicular stomatitis virus in mitotic and interphase cells. Quantitation showed that the appearance of G protein on the surface of mitotic cells was inhibited at least 10-fold when compared with that on interphase cells, even though similar amounts of viral protein were being synthesized. This dramatic inhibition, taken together with the simultaneous inhibition of endocytosis (Berlin, R. D., and J. M. Oliver, 1980, J. Cell Biol. 85: 660-671), points to a general cessation of membrane traffic in the mitotic cell.

Animals↗
PubMed1983

Benzoyl peroxide versus topical erythromycin in the treatment of acne vulgaris.

In a double-blind clinical study in ninety-four subjects a 1.5% (w/v) erythromycin lotion was as effective as 5% (w/v) benzoyl peroxide gel in significantly reducing the number of small inflamed lesions and the overall acne severity. However, benzoyl peroxide also significantly reduced the number of non-inflamed lesions whereas erythromycin had no effect on these lesions. This study supports the view that, although topical erythromycin is of value in the treatment of mild or moderate acne vulgaris, long established, safe and effective remedies should not be replaced by topical antibiotics until more comparative studies and investigations on bacterial resistance have been completed.

Acne Vulgaris↗
PubMed1983

Viral glycoproteins at different stages of intracellular transport can be distinguished using monoclonal antibodies.

Monoclonal antibodies were raised against Semliki Forest virus (SFV) and all were found to recognize the E2 spike glycoprotein. The hybridomas were screened by immunofluorescence microscopy of infected cells to look for antibodies recognizing E2 at different stages of intracellular transport and two (9AB4 and 9AD6) were chosen for further study. Immunocytochemical studies at the light and electron microscopic levels were used to show that 9AB4 recognized E2 at all stages of its transport from the rough endoplasmic reticulum (ER), where it was synthesized, to the cell surface via the smooth ER and Golgi complex. In contrast, 9AD6 only recognized E2 once it had left the ER and entered the stacks of flattened Golgi cisternae. Binding of 9AD6 to E2 did not appear to be the result of the changes in oligosaccharide structure that occur in the Golgi complex and the precise modification detected by 9AD6 remains to be elucidated. A later modification, the cleavage of precursor E2 (p62) to give mature E2, was used to show that 9AD6 bound the latter more tightly than the former, whereas 9AB4 bound both with equal affinity. These results show that monoclonal antibodies might be useful when searching for new modifications to proteins undergoing intracellular transport.

Animals↗
PubMed1982

A monoclonal antibody against a 135-K Golgi membrane protein.

A monoclonal antibody ( 53FC3 ) has been produced against a Golgi membrane protein with a mol. wt. of 135 000 which was originally identified using a polyclonal antiserum. Treatment of isolated, intact Golgi vesicles with protease caused a decrease in mol. wt. of 5000-10 000, whereas in the presence of Triton X-100, the protein was completely degraded. This shows that the protein spans the bilayer and that most of its mass is on the luminal side of Golgi membranes. Using two immunoelectron microscopic techniques, the protein was found in one or two cisternae on one side of the Golgi stack which, in normal rat kidney cells, had 4-6 cisternae. As an illustration of the use to which this monoclonal antibody can be put we present a light microscopic study of the disassembly and reassembly of the Golgi complex during mitosis.

Animals↗
PubMed1982

Viral membrane proteins acquire galactose in trans Golgi cisternae during intracellular transport.

Frozen, thin sections of baby hamster kidney (BHK) cells were incubated with either concanavalin A (Con A) or Ricinus communis agglutinin I (RCA) to localize specific oligosaccharide moieties in endoplasmic reticulum (ER) and Golgi membranes. These lectins were then visualized using an anti-lectin antibody followed by protein A conjugated to colloidal gold. All Golgi cisternae and all ER membranes were uniformly labeled by Con A. In contrast, RCA gave a uniform labeling of only half to three-quarters of those cisternae on the trans side of the Golgi stack; one or two cis Golgi cisternae and all ER membranes were essentially unlabeled. This pattern of lectin labeling was not affected by infection of the cells with Semliki Forest virus (SFV). Infected cells transport only viral spike glycoproteins from their site of synthesis in the ER to the cell surface via the stacks of Golgi cisternae where many of the simple oligosaccharids on the spike proteins are converted to complex ones (Green, J., G. Griffiths, D. Louvard, P. Quinn, and G. Warren. 1981. J. Mol. Biol. 152:663-698). It is these complex oligosaccharides that were shown, by immunoblotting experiments, to be specifically recognized by RCA. Loss of spike proteins from Golgi cisternae after cycloheximide treatment (Green et al.) was accompanied by a 50% decrease in the level of RCA binding. Hence, about half of the RCA bound to Golgi membranes in thin sections was bound to spike proteins bearing complex oligosaccharides and these were restricted to the trans part of the Golgi stack. Our results strongly suggest that complex oligosaccharides are constructed in trans Golgi cisternae and that the overall movement of spike proteins is from the cis to the trans side of the Golgi stack.

Animals↗
PubMed1982

Benzoyl peroxide: lack of sensitization.

A prospective study of 445 patients using benzoyl peroxide, observed regularly over a 12-month period, uncovered only a very low incidence of moderate or severe local reaction. There was, however, a significant level of mild primary irritant dermatitis which settled with continued use. In only 6 patients was there severe local reaction; one patient was lost to follow-up but in the 5 patients patch tested, only one had a contact allergic dermatitis. The study indicates the overall cutaneous safety of benzoyl peroxide.

Acne Vulgaris↗
PubMed1981

Immunocytochemical localization of carcinoembryonic antigen in benign and malignant colorectal tissues. Assessment of diagnostic value.

Immunoperoxidase and immunofluorescence staining for carcinoembryonic antigen (CEA) was performed on paraffin and frozen sections, respectively, of colonic carcinomas (70), liver and lymph node metastases (20), mesenteric nodes (150), mucosa adjacent to carcinoma (40), colonic resection margins (20), normal colon (ten), and colorectal polyps (64) in order to assess its potential diagnostic value. On the basis of this study of the immunocytochemical localization of CEA in colorectal tissues, conclusions were as follows. (1) Localization of CEA to glycocalyx of surface epithelial cells is a normal finding in the colon and is similar in normal colon and mucosa distant and adjacent to infiltrating carcinoma. (2) Although strongly positive cell surface and intraluminal staining frequently correlates with the presence of carcinoma in neoplastic polyps, it is not by itself a reliable diagnostic criterion. (3) Failure to demonstrate CEA in a gland-forming carcinoma makes a diagnosis of colorectal carcinoma unlikely. (4) Poorly differentiated colorectal carcinoma usually contains much less demonstrable surface CEA, but may occasionally stain cytoplasm strongly. (5) Although lymph node micrometastases from colorectal carcinoma are readily demonstrated by immunoperoxidase staining for CEA, screening of hematoxylin and eosin-stained sections by a competent pathologist appears to be adequate for their detection.

Carcinoembryonic Antigen↗
PubMed1981

Transvenous angioplasty of experimental branch pulmonary artery stenosis in newborn lambs.

A dilatable form of bilateral branch pulmonary artery stenosis was created in 27 newborn lambs. Nine lambs were long-term survivors and were dilated with modified Grüntzig balloon dilation catheters. They were allowed to recover for 6-9 weeks, during which time there was no significant change in the mean systolic gradients across the narrowed sites. Thirteen arteries underwent dilation. Dilation was associated with a decrease in the systolic gradient in all cases (from 34.9 mm Hg to 8.1 mm Hg) and an increase in the diameter of the narrowed site (from 4.6 to 7.6 mm) as estimated by angiography. Flows and flow distribution were measured in four lambs before and after unilateral dilation using 15-mu radiolabeled microspheres; in each case, the fraction of total flow to the dilated lung rose after dilation (19.2 to 45.4%), as did the total flow to the dilated lung (30.0 to 69.2 ml/kg-min). Four lambs were catheterized every 2-4 weeks for an average of 16 weeks after dilation; the average gradient in these lambs remained below 10 mm Hg despite considerable growth (from 9.6 to 25.9 kg). Gross pathologic examination showed an intact vascular adventitia in all cases; there were multiple linear tears in the intima in recently (less than 7 days) dilated cases, but complete intimal healing had occurred by 2 months after dilation. No significant morbidity could be attributed to the dilation procedure. These results indicate that clinical trials are warranted.

Angioplasty, Balloon↗