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Biomedical subjects

C M Johnson

Publications and source records attributed to C M Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1990

Electrophoretic purification of the alpha and beta subunits of phosphorylase kinase and evidence in support of the deduced amino acid sequences.

A simple, rapid sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method is presented for isolating the alpha, alpha' and beta subunits of rabbit muscle phosphorylase kinase. The SDS-PAGE procedure can yield milligram amounts of alpha and beta from a single preparative gel and also allows isolation of the alpha' isozyme free of alpha. Notably the method provides the purified subunits in a form amenable to structural analysis. Edman degradation of alpha and alpha' reveal identical NH2-terminal structures. Amino acid analysis of the electrophoretically purified alpha and beta subunits are in good agreement with their deduced primary structures. The amino acid sequence of 488 residues in alpha and 713 residues in beta were determined by gas phase Edman degradation. The data support the recently deduced primary structures of alpha (Zander et al., Proc. Natl. Acad. Sci. USA, 1988, 85, 9381-9385).

Amino Acid Sequence↗
PubMed1990

Phase II trial of 4' deoxydoxorubicin (DXDX) for unresectable non-small cell bronchogenic carcinoma. An Illinois Cancer Council study.

A phase II trial of 4' Deoxydoxorubicin (DXDX) was conducted in unresectable previously untreated non-small cell lung cancer patients. DXDX was administered every 3 weeks by short intravenous infusion at a starting dose of 30 mg/m2, with dose escalation to 40 mg/m2 toxicity permitting. Four responses, all partial, were observed in 35 evaluable patients, for a response rate of 11% (95% confidence limits 3.2% and 26.7%). Myelosuppression was the dose-limiting toxicity. Cardiotoxicity was not seen. DXDX has minimal activity against non-small cell lung cancer as a single agent at the dosage used in this study.

Adult↗
PubMed1990

Radiologic evaluation of penetrating aortic atherosclerotic ulcer.

Patients with penetrating atherosclerotic ulcers of the aorta present with back or chest pain that mimics classic aortic dissection. The pathologic findings, however, are distinctly different from those of aortic dissection in that an atherosclerotic lesion with ulceration penetrates into the internal elastic lamina, allowing hematoma formation within the media of the aortic wall. This may lead to false aneurysm or, rarely, transmural rupture of the aorta. Imaging findings of penetrating aortic atherosclerotic ulcers are also different from those of classic aortic dissection. We have found computed tomography to be especially useful in differentiating between these entities and present several illustrative cases.

Aged↗
PubMed1990

Leishmania mexicana complex: human infections in the Republic of Panama.

Parasites of the genus Leishmania responsible for human cutaneous leishmaniasis in the New World form 2 major taxonomic divisions: the Leishmania braziliensis and the L. mexicana complexes. We report the isolation and characterization of the L. mexicana complex among humans in the Republic of Panama. Characterization was based on parasite morphology, pathogenesis in infected golden hamsters, cellulose acetate isoenzyme electrophoretic mobilities, and membrane-specific monoclonal antibodies using the radioimmune binding assay technique.

Adolescent↗
PubMed1990

Identification of Staphylococcus aureus binding proteins on isolated porcine cardiac valve cells.

Infective endocarditis caused by Staphylococcus aureus may be initiated by bacterial binding to cardiac valve cells. We investigated binding of whole S. aureus organisms to preparations of isolated porcine cardiac valve proteins. Cultured endothelial and subendothelial cells were surface labeled with iodine 125. After preabsorption with Escherichia coli, an organism that only rarely causes infective endocarditis, binding of surface proteins to S. aureus was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent autoradiography. The results showed that cardiac valve endothelial cells expressed a major S. aureus-binding protein with an approximate apparent molecular weight of 120,000. In contrast, cardiac valve subendothelial cells expressed on their surface a single species of binding protein with an approximate apparent molecular weight of 220,000; immunoblot analysis suggested that this protein was fibronectin. We also used radiolabeled S. aureus to probe cellular proteins transferred to nitrocellulose membranes. This technique identified a 125,000 molecular weight protein that bound S. aureus in endothelial cell extracts. We conclude that specific S. aureus binding to cardiac valve cells is mediated by different receptors for endothelial and subendothelial cells.

Animals↗
PubMed1989

Reaction of fluorescein isothiocyanate with an ATP-binding site on the phosphorylase kinase alpha subunit.

Phosphorylase kinase can be labeled specifically on the alpha subunit with fluorescein 5'-isothiocyanate (FITC) which concomitantly inactivates the enzyme (T. G. Sotiroudis and S. Nikolaropoulus (1984) FEBS Lett. 176, 421-425). Labeled peptides have been purified and their primary structure has been determined. The amino acid sequence of the fluorescein-labeled tryptic peptide is Lys-Met-Gln-Asp-Gly-Tyr-Phe-Gly-Gly-Ala-Arg. The environment of this fluorescein-labeled lysine has been determined by sequencing peptides isolated from a Staphylococcus aureus V8 digest and two further cyanogen bromide fragments of the purified [14C]carboxymethylated alpha subunit. The partial sequences obtained have then been localized in the primary structure of the alpha subunit [Zander et al. (1988) Proc. Natl Acad. Sci. USA 85, 2929-2933]. Both the incorporation of the fluorescent label and enzymatic inactivation are inhibited by ATP only at pH 7.0; ADP and AMP do not protect. Kinetic analysis reveals a competition between ATP and FITC; a Ki for ATP of 728 +/- 100 microM has been determined.

Adenosine Triphosphate↗
PubMed1989

Phase II trial of spirogermanium in advanced non-small cell lung cancer. An Illinois Cancer Council Study.

A phase II trial of spirogermanium was conducted in advanced previously untreated non-small cell lung cancer patients. The drug was given by intravenous infusion 3 times per week for 2 weeks, twice per week for the next 2 weeks, and then weekly. Starting dose was 125 mg/m2, and dose escalation of 25 mg/m2 per week was required in the absence of toxicity to a maximum dose of 200 mg/m2 per infusion. Fifteen eligible patients were treated, and no objective responses were seen. Primary toxicity was neurologic and reversible after withdrawal of the drug. We conclude that spirogermanium is not active against non-small cell lung cancer in the dosage used in this study.

Adult↗
PubMed1989

Insulin resistance in uremia: an in vivo and in vitro study.

Insulin-mediated glucose metabolism was examined in vivo and in vitro in a chronically uremic (4-week) rat model established by a 90% nephrectomy. Using the euglycemic insulin clamp technique, uremic rats demonstrated a 28% reduction (P less than .01) in total body glucose disposal compared with pair-fed controls. Suppression of hepatic glucose production by insulin was not impaired. The ability of insulin to promote glycogen synthesis by the soleus muscle in vitro was normal in uremic rats. In contrast, the ability of insulin to enhance both glycolysis and glucose oxidation by the soleus muscle was significantly reduced (P less than .01) in uremic rats. These results provide evidence that at least two intracellular metabolic defects, ie, in the glycolytic and glucose oxidative pathways, contribute to the insulin resistance of chronic uremia.

Animals↗
PubMed1989

Treatment of American cutaneous leishmaniasis with orally administered allopurinol riboside.

Eighteen patients received 1,250 mg of allopurinol riboside (AR) four times daily for 28 d. Nine of the patients concurrently received 500 mg probenecid (PB) four times daily. Cure was assessed clinically and parasitologically. Patients who had culture-positive and nonhealing lesions 3 mo after therapy received pentavalent antimony. Of the nine patients who received AR alone, four (44%) had clinical improvement at the end of therapy and two (22%) were culture-negative. A third patient became culture negative at 2 mo after therapy. The culture-negative patients were completely healed at 1 mo and remained so at 1 y after therapy. Of the nine patients who received AR plus PB, four had complete healing and two had clinical improvement at the end of therapy; however, all patients remained culture-positive. At 2-3 mo after therapy, six (67%) of the patients were completely healed, and of these, five (56%) were culture-negative. The drug was well-tolerated.

Adult↗
PubMed1989

Castor-oil induced diarrhoea in ponies: a model for acute colitis.

A reproducible, reversible model of colitis induced in ponies by administering castor oil (2.5 ml/kg bodyweight [bwt] per os) was characterised by abdominal pain, fever, watery diarrhoea, dehydration, hypovolaemia, toxaemia, leucopenia, decreased serum Cl, Na and K levels and metabolic acidosis. The signs were most severe between 24 and 48 h post induction, stabilisation was frequently observed after 72 h, although diarrhoea could persist beyond 96 h. Morphological and in vitro transport studies (right ventral colon) were conducted on tissues from animals destroyed at 24, 48 and 72 h. In the caecum and colon, surface epithelial disruption and exfoliation from the basement membrane occurred between 24 and 48 h. Early signs of recovery were evident by replenishment of denuded areas with columnar epithelium at 72 h. The crypt epithelium was unaffected throughout the intestinal tract. In vitro transport studies were consistent with the morphological findings. Decreased Na-Cl absorption and normal Cl secretion indicated an impaired surface epithelium coincident with an undamaged cryptal epithelium. Increased mucosal permeability was demonstrated by high ionic conductance and large unidirectional isotopic fluxes. Tissue conductance improved during in vitro incubation suggesting epithelial repair after removal of castor oil. Changes in the population and proportion of bacteria in the faeces as diarrhoea ensued were confirmed at necropsy with a predominance of E. coli and Enterobacter/Klebsiella sp in the large bowel. The experimental induction of castor oil colitis showed many similarities to intestinal endotoxaemia and the secretory type diarrhoea encountered in naturally occurring acute colitis syndromes in horses. The model could prove applicable in studying the pathophysiological mechanisms precipitating such life-threatening disorders.

Acidosis↗
PubMed1989

CT-guided biopsy: prospective analysis of 1,000 procedures.

The authors prospectively analyzed 1,000 biopsies guided with computed tomography (CT) and performed in 955 patients over a 30-month period. All patients were followed up from 3 months to 2 years. The biopsies were performed in an average of 22 minutes (range, 3-85 minutes) by 26 different radiologists; five radiologists performed 547 of the procedures. Of the 1,000 biopsies, 722 were performed in areas in the liver, retroperitoneum, pancreas, pelvis, and adrenal glands. Of 69 errors in diagnosis, 67 were falsely negative and two were falsely positive; 747 true-positive and 184 true-negative diagnoses were made. CT-directed biopsy for accurate diagnosis was 91.8% sensitive and 98.9% specific, with a positive predictive value of 99.7% and a negative predictive value of 73.3%. Of 11 patients with complications, seven had hematomas, three had pneumothorax, and one had hematuria. No deaths occurred, and only one patient required surgery.

Adrenal Glands↗
PubMed1989

Presence of antibodies in the sera of patients with Graves' disease recognizing a 23 kilodalton fibroblast protein.

We examined whether antibodies (present in sera from patients with Graves' disease) might be directed against a connective tissue cellular component of the anatomical regions affected in the peripheral manifestations of that disease. Accordingly, we performed immunoblot analyses of cultured retroocular and pretibial fibroblasts. Retroocular connective tissue was obtained during orbital decompression surgery (n = 7) and at autopsy from normal individuals (n = 2). Pretibial skin biopsies were obtained from patients with pretibial dermopathy (n = 3) and at autopsy (n = 2). In addition, biopsies from other regions [extraocular muscle (n = 6), thyroid (n = 2), and abdominal skin (n = 3)] were also collected at surgery or autopsy. Serum samples were obtained from patients with severe Graves' ophthalmopathy (n = 31), hyperthyroid Graves' disease without overt ophthalmopathy (n = 13), nodular thyroid disease (n = 7), Hashimoto's thyroiditis (n = 7), rheumatoid arthritis (n = 5), and systemic lupus erythematosus (n = 3) and from normal individuals (n = 33). Electrophoresed fibroblast proteins were immunoblotted with 1:100 dilutions of sera using an antihuman immunoglobulin G-alkaline phosphatase conjugate. Antibodies against a 23kDa fibroblast protein were present in the sera from 24 of 44 (56%) of patients with Graves' disease with or without ophthalmopathy, 0 of 7 nodular thyroid disease, 0 of 7 Hashimoto's thyroiditis, 0 of 5 rheumatoid arthritis, 0 of 3 systemic lupus erythematosus, and 5 of 33 (15%) normal subjects. Significant differences in the observed frequency of antibodies existed between the Graves' disease group and the normal control group (P less than 0.01) or those patients with the other conditions (P less than 0.01). This 23kDa antigen was apparent in fibroblasts derived from individuals with Graves' disease as well as normal individuals and was present in fibroblasts from all anatomical sites studied. It was the sole protein uniquely recognized by sera from patients with Graves' disease. However, this serum reactivity did not appear to be related to the presence of clinically overt ophthalmopathy or pretibial dermopathy. Subcellular localization studies disclosed that the antigen was present in the supernatant but not the pellet resulting from a 100,000 x g centrifugation of whole cell sonicates. Antibodies against a 23kDa fibroblast protein are present in the majority of sera from patients with Graves' disease and rarely in sera from either normal individuals or those with other thyroid disorders or autoimmune diseases. Our results suggest the possibility that antibodies directed against this fibroblast antigen may be related to the developm

Antibodies↗
PubMed1989

[Mucocutaneous leishmaniasis in Panama. Etiologic agent, epidemiologic and clinical aspects].

From November 1985 to December 1988, 33 patients were enrolled at Santo Tomas Hospital and Gorgas Memorial Laboratory to study the etiology, epidemiology and clinical characteristics of mucocutaneous leishmaniasis. Seventeen were males and 16 females, 14 to 80 years old from the endemic rural areas of the provinces of Panama, Colón, Coclé, Darién, Veraguas, Bocas del Toro and San Blas. In 8 patients the respiratory mucosa involvement occurred at the time of the primary infection and 25 had the involvement after an incubation period of 2 to 30 years. Twenty one of these 25 patients had a clear history of cutaneous leishmaniasis and the characteristic depressed and hyperpigmented scar of a previous leishmanial infection. The Montenegro skin test was positive in all the patients, serology in 84%, direct smear in 47%, histopathology in 37% and culture in 26%. The strains were characterized as L. braziliensis panamensis by electrophoresis of isoenzymes. Possible risk factors in development of MCL were found to be female sex and the lack of past treatment of CL. The mucosal involvement was mild in the majority of the patients, the infection was localized in the nasal mucosal (nasal septum and inferior turbinate) in 91% of the patients, and the most common symptoms were epistaxis, nasal obstruction and rhinorrhea.

Adolescent↗
PubMed1989

[Blister dermatitis caused by Epicauta flagellaria (Erichson) (Coleoptera: Meloidae) species].

This paper is the first published report of vesicular dermatitis due to blister beetles of the family Meloidae in Panamá. A familial outbreak of bullous dermatitis caused by Epicauta flagellaria (Erichson) is described. All previous cases known in the Gorgas Memorial Laboratory were associated with E. isthmica Werner. Bullous lesions are produced when cantharidin, a vesicating toxin contained in the beetle's body, is released at the time the insect is crushed or rubbed upon the exposed skin. Rules for the treatment and prevention of this disease are indicated.

Animals↗
PubMed1988

The complete primary structure of the cellular retinaldehyde-binding protein from bovine retina.

Cellular retinaldehyde-binding protein (CRALBP) carries 11-cis-retinol and 11-cis-retinaldehyde as endogenous ligands and may be a functional component of the visual cycle. The complete amino acid sequence of CRALBP from bovine retina has been determined by direct microanalysis of the protein. Bovine CRALBP contains 316 residues in a single amino-terminal-blocked chain corresponding to a molecular weight of 36,421, inclusive of the blocking group. Overlapping peptides were generated by cleavage of lysyl, arginyl, methionyl, glutamyl, and one tryptophanyl bond and sequenced by gas-phase Edman degradation. Analysis of amino-terminal arginyl and methionyl peptides by fast atom bombardment mass spectrometry identified the N alpha-blocking group as an acetyl moiety, and tandem mass spectrometry provided the sequence of the first 9 residues. Comparison of CRALBP with other known protein sequences reveals no significant structural relatedness. The present results provide a basis for relating CRALBP domains with physiological function and for the future development of a more detailed three-dimensional model of the interaction of 11-cis-retinaldehyde with protein.

Amino Acid Sequence↗
PubMed1988

Glycoproteins synthesized by cultured cardiac valve endothelial cells: unique absence of fibronectin production.

We have previously reported that cultured porcine cardiac valve endothelial cells released less fibronectin into the culture supernatant when compared to other porcine endothelial cells. In this report we compared the spectrum of glycoproteins synthesized by cardiac valve endothelial cells to glycoproteins synthesized by comparison endothelial cells derived from the ascending thoracic aorta. The cells were endogenously radiolabeled and extracted with detergent. Glycoproteins in the cell extracts were then isolated on wheat germ lectin-agarose and compared using autoradiography following polyacrylamide gel electrophoresis. Fibronectin was identified by immunoblotting with specific antibody. The results showed that the outstanding difference between the endothelial cell types was the virtual absence of fibronectin in the cardiac valve endothelial cell extract.

Animals↗
PubMed1988

Do metal ions promote the re-activation of the 2,3-bisphosphoglycerate-independent phosphoglycerate mutases?

It has been reported [Smith, McWilliams & Hass (1986) Biochem. Biophys. Res. Commun. 136, 336-340] that addition of certain metal ions, notably Co2+ and Mn2+, promoted the refolding of denatured phosphoglycerate mutase from wheat germ. We have re-investigated these experiments and have shown that, when precautions are taken to avoid artefacts in the assay system, the metal ions do not promote any re-activation of the denatured wheat-germ or Aspergillus nidulans enzymes. An alternative explanation is offered for the observations of Smith et al. (1986).

2,3-Diphosphoglycerate↗