Activity of herpes simplex virus type 1 latency-associated transcript (LAT) promoter in neuron-derived cells: evidence for neuron specificity and for a large LAT transcript

By using chloramphenicol acetyltransferase (CAT) assays in neuron-derived cell lines, we show here that promoter activity associated with the herpes simplex virus type 1 latency-associated transcript (LAT) had neuronal specificity. Promoter activity in these transient CAT assays coincided with a DNA region containing excellent RNA polymerase II promoter consensus sequences. Primer extension analysis in a LAT promoter-CAT plasmid construct placed the start of transcription about 28 nucleotides from the first T in the consensus TATA box sequence. Neuronal specificity of this promoter was suggested by examining the effect of sequences upstream of the promoter on CAT activity in neuronal versus nonneuronal cells. In nonneuronal cells, promoter activity was decreased 3- to 12-fold with the addition of upstream sequences. In contrast, in neuron-derived cells, the addition of upstream sequences did not decrease promoter activity. The LAT promoter predicted by our transient CAT assays was located over 660 nucleotides upstream from the 5' end of the previously mapped 2-kilobase (kb) LAT. This unusual location was explained by in situ and Northern (RNA) blot hybridization analyses that suggested that LAT transcription began near the promoter detected in our CAT assays, rather than near the 5' end of the 2-kb LAT. In situ hybridization with neurons from latently infected rabbits detected small amounts of LAT RNA within 30 nucleotides of the consensus TATA box sequence. This suggested that LAT transcription began near this TATA box. Northern blot hybridization of RNA from ganglia of latently infected rabbits revealed a faint 8.3-kb band of the same sense as LAT. We conclude that (i) the LAT promoter has neuronal specificity, (ii) the LAT promoter is located over 660 nucleotides upstream of the 5' end of the previously characterized stable 2-kb LAT, (iii) LAT transcription begins about 28 nucleotides from the first T of the consensus TATA box sequence and extends to near the first available polyadenylation site approximately 8.3 kb away, and (iv) this 8.3-kb RNA may be an unstable precursor of the more stable 2- and 1.3-kb LATs.

Chemical pathways of peptide degradation. III. Effect of primary sequence on the pathways of deamidation of asparaginyl residues in hexapeptides

Deamidation of Asn residues can occur either by direct hydrolysis of the Asn residue or via a cyclic imide intermediate. The effects of primary sequence on the pathways of deamidation of Asn residues were studied using Val-Tyr-X-Asn-Y-Ala hexapeptides with substitution on the C-terminal side (Y) and on the N-terminal side (X) of the Asn residue. In acidic media the peptides deamidate by direct hydrolysis of the Asn residue to yield only Asp peptides, whereas under neutral or alkaline conditions, the peptides deamidate by formation of the cyclic imide intermediates which hydrolyze to yield both isoAsp and Asp peptides. At neutral to alkaline pH's the rate of deamidation was significantly affected by the size of the amino acid on the C-terminal side of the Asn residue. The amino acid on the C-terminal side of the Asn residue has no effect on the rate of deamidation at acidic pH. Changes in the structure of the amino acid on the N-terminal side of the Asn residue had no significant effect on the rate of deamidation at all the pH's studied. For peptides that underwent deamidation slowly, a reaction involving the attack of the Asn side chain on the peptide carbonyl carbon resulting in peptide bond cleavage was also observed.

Chemical pathways of peptide degradation. II. Kinetics of deamidation of an asparaginyl residue in a model hexapeptide

Deamidation of Asn residues is a major chemical pathway of degradation of peptides and proteins. To understand better the external factors that influence deamidation, we studied the degradation of the hexapeptide Val-Tyr-Pro-Asn-Gly-Ala, a fragment of adrenocorticotropic hormone, by HPLC. The deamidation of this model peptide showed marked dependence on pH, temperature, and buffer composition. In the pH range 5 to 12, the peptide deamidated exclusively via a cyclic imide intermediate with the formation of both the Asp- and the isoAsp-hexapeptides. Buffer catalysis was also observed in the pH range of 7 to 11. However, at acidic pH's, the pathway of deamidation involved direct hydrolysis of the amide side chain of Asn residue to produce only the Asp-hexapeptide.

Chemical pathways of peptide degradation. I. Deamidation of adrenocorticotropic hormone

Deamidation of Asn residues is one of the major chemical pathways of degradation of proteins and peptides. Adrenocorticotropic hormone (ACTH), a 39-amino acid polypeptide with a single Asn residue, was shown in this study to be a useful model polypeptide for the study of the effects of pH and buffer concentration on the rate and pathway of deamidation. The disappearance of ACTH and appearance of deamidated ACTH were monitored by isoelectric focusing (IEF), and ammonia production was monitored spectrophotometrically using a coupled enzymatic assay. Using these analytical methods, the deamidation of ACTH was shown to follow pseudo-first-order kinetics and was dependent on pH and buffer concentrations. The separation of the deamidated ACTHs (Asp-ACTH and isoAsp-ACTH) from ACTH was successful, but attempts to separate Asp-ACTH from isoAsp-ACTH using cation-exchange HPLC and IEF were unsuccessful. Using bovine protein carboxymethyltransferase (PCM), which selectively methylates the carboxyl group of isoAsp residue, the isoAsp-ACTH could be detected at pH 7.0 and 9.6 but not at pH 1.9. These data support the hypothesis that under neutral and alkaline conditions, deamidation of ACTH proceeds through the formation of a cyclic imide intermediate (slow step), followed by its hydrolysis to the Asp-ACTH and isoAsp-ACTH (fast step). Under acidic conditions, the reaction appears to proceed via direct hydrolysis of the Asn residue to form Asp-ACTH without the formation of a cyclic imide intermediate.

Regulation of low molecular weight insulin-like growth factor binding proteins in experimental diabetes mellitus

Circulating insulin-like growth factor (IGF) bioactivity is reduced in animals and patients with diabetes mellitus. We sought to determine whether the availability and levels of specific IGF binding proteins (BPs) are altered in animals with experimental diabetes, and might contribute to changes in circulating IGF bioactivity in experimental diabetes. Female Sprague-Dawley rats were administered streptozotocin or citrate buffer iv, and then killed either 3 days later, or else after 4-day insulin treatment (7.5 U/kg human NPH twice daily), or 2 days after insulin was discontinued. Serum [125I]IGF-I binding activity was markedly increased in diabetic animals compared to controls when analyzed by Sephacryl S-200 chromatography, dot blot, and affinity labeling techniques, due to increased binding to low mol wt BPs (81 +/- 4% of ligand eluting with low mol wt BPs in diabetic serum vs. 22 +/- 3% in control, P less than 0.001). In contrast, activated charcoal removed ligand from these BPs and underestimated the availability of BPs in diabetes. Serum binding activity fell toward control levels during insulin therapy, then rose again after insulin was withdrawn, corresponding to changes in metabolic status. To distinguish changes in specific BPs, serum proteins were separated by 13% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, then transferred to nitrocellulose. Ligand blotting with [125I]IGF-I demonstrated that serum levels of a 32 K mol wt IGF BP are markedly increased in diabetic rats and decline during insulin therapy. Levels of this 32 K IGF BP rose again after insulin was discontinued, demonstrating regulation in accordance with changes in insulin and metabolic status. Western analysis and affinity labeling with immunoprecipitation revealed that this 32 K protein is distinct from the 34 K fetal rat BP, and is immunologically related to the type 1 human IGF BP. We conclude that circulating [125I]IGF-I binding activity is markedly increased in animals with acute streptozotocin-induced diabetes, due to changes in low mol wt proteins, including a 32 K type 1 IGF BP that is regulated by changes in insulin and/or metabolic status. Regulation of low mol wt IGF BPs by insulin, and perhaps other factors, may play an important role in the modulation of tissue growth factor bioactivity in metabolic disease.

Hormone and cytotoxic drug responsiveness of cultured human breast cancer cells resistant to specific hormones

Attempts have been made to develop sublines of MCF-7 cells resistant to the growth-inhibitory actions of medroxyprogesterone acetate (MPA), dexamethasone (DEX), anti-oestrogens or high-dose oestradiol (E2) by prolonged exposure to high hormone concentrations. While high degrees of resistance to MPA, DEX and E2 were achieved, cells remained anti-oestrogen-sensitive after prolonged treatment with 4 microM tamoxifen (TAM) or the anti-oestrogen LY 117018 (LY). Cells resistant to DEX were also resistant to MPA, while cells resistant to high-dose E2 remained sensitive to TAM. Cells resistant to MPA and E2 appeared to be less responsive to cytotoxic drugs than wild-type cells, while resistance to DEX was associated with increased sensitivity. The responses of tumours to cytotoxic drugs may be affected by prior endocrine therapy.

Monoclonal antibody UJ13A recognizes the neural cell adhesion molecule (NCAM)

Monoclonal antibody (MAb) UJ13A, raised against 16-week-old human foetal brain, recognizes an antigen present on the majority of tissues of neuro-ectodermal origin. The binding profile of this antibody is similar to the known distribution of the neural cell adhesion molecule (NCAM). Although detailed immunohistological and immuno-cytochemical studies with the MAb have been published previously, we demonstrate here, through investigations of selected tissues and cell lines, that the binding profile of an anti-NCAM antiserum is similar to UJ13A. Additional indirect evidence suggesting that UJ13A recognizes NCAM comes from Northern blot analysis of cell lines either binding or not binding UJ13A as determined by indirect immunofluorescence. Only those cell lines known to bind UJ13A express high levels of NCAM mRNA. Western blot analysis of extracts of human brain show that UJ13A recognizes proteins of 180 and 140 kDa in addition to a very weak band of 120 kDa. This data corroborates the suggestion that UJ13A recognizes NCAM as these 3 isoforms of the protein are identified in human brain. Final confirmation of the specificity of UJ13A comes from the study of 3T3 fibroblasts transfected with a cDNA coding for the 125 kDa isoform of human muscle NCAM. UJ13A selectively recognizes these transfectants and binds to a 125 kDa protein isolated from the cells by Western blot analysis. Thus we conclude from these immunological, biochemical and molecular studies that the antigen recognized by the UJ13A MAb is the neural cell adhesion molecule.

Monoclonal antibody 3F8 recognises the neural cell adhesion molecule (NCAM) in addition to the ganglioside GD2

The monoclonal antibody 3F8 has been described as binding to the ganglioside GD2. This antibody, of the IgG3 isotype, has been used in immunotherapy, radioimmunolocalisation and targeted radiation therapy. 3F8 was originally observed to have a binding profile similar to two monoclonal antibodies, UJ13A and 5.1.H11, characterised as binding to the neural cell adhesion molecule (NCAM). This observation has also been confirmed using a hetero-antiserum prepared against purified NCAM. The cross-reactivity of 3F8 with NCAM has been confirmed by cross-blocking studies with an anti-NCAM antiserum, and by direct immunoprecipitation and gel electrophoresis. In addition, we show that 3F8 binds to human NCAM from 3T3 fibroblasts transfected with NCAM cDNA constructs. It is possible that the common epitope shared by GD2 ganglioside and NCAM involves sialic acid residues common to both the ganglioside and the glycoprotein.

Stability of protein pharmaceuticals

Recombinant DNA technology has now made it possible to produce proteins for pharmaceutical applications. Consequently, proteins produced via biotechnology now comprise a significant portion of the drugs currently under development. Isolation, purification, formulation, and delivery of proteins represent significant challenges to pharmaceutical scientists, as proteins possess unique chemical and physical properties. These properties pose difficult stability problems. A summary of both chemical and physical decomposition pathways for proteins is given. Chemical instability can include proteolysis, deamidation, oxidation, racemization, and beta-elimination. Physical instability refers to processes such as aggregation, precipitation, denaturation, and adsorption to surfaces. Current methodology to stabilize proteins is presented, including additives, excipients, chemical modification, and the use of site-directed mutagenesis to produce a more stable protein species.

Neural cell adhesion molecule (NCAM) is the antigen recognized by monoclonal antibodies of similar specificity in small-cell lung carcinoma and neuroblastoma

We describe reagents from 2 workshops which had been identified as recognizing the same or very similar antigens based on their tissue reactivity. Examination of their tissue specificity led us to the conclusion that this was similar to the expression of the neural cell adhesion molecule (NCAM). We also describe the use of a transfection-based assay to show that these reagents do recognize NCAM. 3T3 cells were transfected with a full-length clone of human NCAM. Indirect immunofluorescence studies showed binding of all related antibodies to the transfectants, but not to the control 3T3 cells. In addition, biochemical analysis using certain antibodies in the cluster confirm that they detect NCAM in the transfectants. Our study shows the benefits of using workshops to compare monoclonal antibodies and a molecular approach to define the antigens recognized by such reagents.

Insulin and insulin-like growth factor I in brain tumors: binding and in vitro effects

We have measured insulin and insulin-like growth factor I (IGF-I) binding in human gliomas, meningiomas, and normal brain and studied the effect of insulin on the morphology, proliferation, and differentiation of central nervous system tumor and normal fetal cells in culture. Specific 125I-insulin and 125I-IGF-I binding was demonstrated by competition-inhibition binding assays. Insulin binding was measured in plasma membrane preparations from 9 freshly isolated human meningiomas, 4 glioblastomas multiforme (GBMs), a low-grade glioma, a normal adult brain, and a fetal brain. IGF-I binding was measured in similar preparations from 5 meningiomas, 4 GBMs, a low-grade glioma, and a normal adult brain. Incubations were carried out at 4 degrees C for 18 to 20 hours. Meningiomas showed higher specific insulin binding per 0.25 mg of protein than GBMs (19% versus 3%, P less than 0.005), and this difference was not related to small differences observed in insulin degradation. By contrast, IGF-I binding was significantly higher in gliomas than in meningiomas (27% versus 12%, P less than 0.05). Also, IGF-I binding was significantly higher than insulin binding in GBMs (27% versus 3%, P less than 0.03); binding of both IGF and insulin was high in meningiomas. In normal adult brain IGF-I and insulin binding was 7 to 10%. The ability of insulin to support and enhance the growth of central nervous system tumor cells in culture was investigated. Cell cultures were derived from a freshly isolated glioblastoma, a low-grade glioma, and 3 meningiomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic artery aneurysm

A 67-year-old man presented with epigastric pain and underwent cholecystectomy for acute acalculus cholecystitis. Exploration revealed a large aneurysm in the hepatic artery. One week later, the patient developed jaundice, ascending cholangitis and common bile duct obstruction. He was treated with percutaneous transhepatic drainage with dramatic improvement, then underwent an emergency aneurysm resection operation. He is now well, 8 months postoperatively. Due to the high mortality rate associated with hepatic artery aneurysm, treatment is primarily surgical with aneurysmorrhaphy or direct arterial reconstruction utilizing either autogenous saphenous vein or prosthetic grafts. For inaccessible aneurysms or when patients are unfit to withstand surgery, embolization is a useful alternative.

Distribution of dystrophin, nebulin and Ricinus communis I (RCA-I)-binding glycoprotein in tissues of normal and mdx mice

Dystrophin, the protein product of the Duchenne muscular dystrophy (DMD) gene locus, appeared as an immunoreactive triplet of polypeptides in striated muscle tissues from normal mice on Western blot analysis. In smooth muscle tissues, an immunoreactive doublet of corresponding molecular weight was detected. No dystrophin was found in normal mouse brain, not even after enrichment for the Triton X-100 insoluble fraction. Dystrophin was absent from all corresponding tissues from the mdx mutant mouse strain which is known to lack dystrophin. The possibility that these immunoreactive bands represent isoforms is discussed. We have also investigated two other high molecular weight proteins which show secondary abnormalities in DMD muscle, namely nebulin and the 370 kDa Ricinus communis I lectin (RCA I)-binding glycoprotein. Nebulin levels were reduced in skeletal muscle from 6-week-old mdx mice but not in oesophagus from the same animals. By contrast, the RCA I-binding 370 kDa glycoprotein which is greatly reduced in DMD skeletal muscle was present in normal amounts in mdx skeletal muscle. These findings show, for the first time, that mdx myopathy differs from DMD myopathy not only morphologically, but also in its secondary biochemical abnormalities.

[Membrane changes in Duchenne/Becker muscular dystrophy: lectin binding and localization of dystrophin]

An RCA I-lectin binding glycoprotein of Mr = 370 kD is missing from or altered in the plasma membrane of Duchenne muscular dystrophy (DMD) skeletal muscle. In the present study the carbohydrate chain of this glycoprotein was localized to the external face of the plasma membrane in human skeletal muscle, and dystrophin, the protein product of the DMD gene, was localized to the inner (cytoplasmic) face. On double labelled Western blots the two proteins appeared as closely apposed but distinctly separate bands. Comparison of the plasma membrane binding of five lectins with overlapping sugar specificities in skeletal muscle from patients with DMD and the allelic milder disease form, Becker muscular dystrophy (BMD) showed that the RCA I-binding glycoprotein also strongly binds to phytohaemagglutinin, thereby largely characterising the carbohydrate binding site. This glycoprotein was absent or altered in DMD and markedly reduced in clinically manifest BMD but present in preclinical clinical BMD. There was no general depletion of plasma membrane glycoproteins in DMD because consistent plasma membrane binding could be demonstrated by peanut and maclura pomifera lectin. The possible implications of these findings for the pathogenesis of DMD/BMD are discussed.

Physicians and DRGs. Hospital management alternatives

Rising health care costs in general and hospital costs in particular have placed significant financial strain on federal programs such as Medicare. It was with this in mind that the Reagan administration in 1983 initiated Medicare's new prospective payment system based on diagnostic-related groups (DRGs) to reduce the growth rate of Medicare expenditures. The introduction of DRGs has generated significant controversy in the health care community. The DRG system may necessitate consideration of four new management alternatives by hospital administrators: increased monitoring and regulation of physicians, profit-loss sharing arrangements between physicians and hospital management, development of collective protocols among physicians, and bedside budget balancing. This study examines the opinions of a random sample of 838 physicians from the West North-Central region regarding these management alternatives. The findings suggest that physicians have strong negative opinions about these management alternatives and believe that they will have a negative impact on the health care system. The development of collective protocols emerges as the most likely acceptable alternative among physicians, but even collective protocols as an alternative promise limited success.

Dystrophin and nebulin in the muscular dystrophies

Skeletal muscle from patients with 5 different forms of muscular dystrophy and from 6 fetuses at high risk (95%) for Duchenne muscular dystrophy (DMD) were probed with specific antibodies for the presence of dystrophin and nebulin. Dystrophin was absent in all 5 patients with DMD and 4 of 6 fetuses at high risk for DMD and present in trace amounts in the remaining two. Dystrophin was also undetectable in one borderline DMD/Becker muscular dystrophy (BMD) case and reduced in 2 of 4 cases of BMD. In contrast, dystrophin was present in all 16 biopsies from 4 other types of muscular dystrophy (congenital, limb girdle, Emery-Dreifuss and facioscapulohumeral). Nebulin profiles varied with the type, severity and duration of the dystrophic process. Nebulin was present in 5 of 6 DMD fetal samples but vastly reduced or absent in all samples of clinically manifest DMD.

Dual-label autoradiographic analysis of human skin fibroblast and myoblast proteins by two-dimensional polyacrylamide gel electrophoresis using immobilised pH gradients in the first dimension

Horizontal two-dimensional polyacrylamide gel electrophoresis with immobilised pH gradients in the first dimension has been applied to the analysis of human skin fibroblast and muscle myoblast total cell proteins. Excellent two-dimensional separations of skin fibroblast proteins were obtained using pH 4-10 immobilised pH gradient gels with a long interelectrode distance (16 cm), but resolution was degraded, particularly of the more acidic proteins, by the use of shorter (10 cm) gels. Improved resolution of acidic and basic proteins was obtained using separate pH 4-7 and pH 7-10 immobilised pH gradient gels respectively in the first dimension. Two-dimensional protein maps of skin fibroblast proteins were visualised both by silver staining and by autoradiography of samples labelled synthetically with [35S]methionine. Horizontal two-dimensional electrophoresis, using pH 4-7 and pH 7-10 immobilised pH gradient gels in the first dimension, was applied to the analysis of protein samples from skin fibroblasts and muscle myoblasts dual-labelled synthetically with [35S]methionine and [75Se]selenomethionine in an attempt to identify sets of proteins specific to each cell type. In addition, two-dimensional maps or protein samples derived from normal individuals and patients with Duchenne muscular dystrophy were compared to search for protein changes associated with the disease state. Although sets of qualitative protein spot differences were observed by visual inspection of the two-dimensional gels, more rigorous qualitative and quantitative analysis of the patterns using a computerised analysis system will be required to obtain the maximum amount of information from these data.

Calmodulin-binding profiles for nebulin and dystrophin in human skeletal muscle

Nebulin and dystrophin are two high-molecular-mass skeletal muscle proteins that have both been associated with the defective gene in Duchenne muscular dystrophy, although the function of neither protein is known. Other high-molecular-mass, calmodulin-binding proteins have recently been implicated in regulating calcium release from skeletal muscle. Western blots of human skeletal muscle biopsy samples were probed with biotinylated calmodulin; nebulin was identified as a prominent high-molecular-mass calmodulin-binding protein but dystrophin did not bind detectable amounts of biotinylated calmodulin. Dystrophin was absent in a Duchenne muscle biopsy.

Computed tomography in the evaluation of adrenal glands in infants and children

The most sensitive indicators of an abnormal adrenal gland have been a change in the margin of the gland from concave or straight to convex, and the presence of calcification. Large adrenal glands that have preserved normal shape and in postintravenous enhancement show homogeneous increased density indicate hyperplasia.

A comparative study of protein synthesis by keratinocytes and fibroblasts in vitro using two-dimensional gel electrophoresis and dual isotope autoradiography

A procedure is described for the detection of keratinocyte specific proteins. Fibroblasts and keratinocytes were isolated from human skin and radiolabelled in vitro. Samples were separated by two-dimensional polyacrylamide gel electrophoresis to compare the proteins synthesised by the different types of cultured skin cells. Dual label autoradiography of samples radiolabelled with [35S]methionine and [75Se]selenomethionine was used to identify keratinocyte specific proteins. We report 45 keratinocyte-specific components and identify some of these proteins. The differential expression of these proteins and their relevance to epidermal differentiation are discussed.

Hybrid Isoelectric Focusing Using Mixed Synthetic-Carrier Ampholyte-Immobilized pH Gradient Gels

An exciting recent innovation in isoelectric focusing (IEF) has been the development of Immobiline reagents (LKB) (1) for the preparation of polyacrylamide gels containing immobilized pH gradients (IPGs). The Immobilines are a series of seven acrylamide derivatives with the general structure: [Formula: see text] where R contains either a carboxyl (acidic Immobilines) or a tertiary amino (basic Immobilines) group, forming a series of buffers with different pK values (3.6, 4.4, 4.6, 6.2, 7.0, 8.5, 9.3). IPGIEF gels are prepared in the same manner as conventional gradient polyacrylamide gels using a concentration gradient, stabilized with a density gradient (e.g., glycerol), of the Immobiline reagents mixed with acrylamide and N,N'-methylene bisacrylamide (Bis) under the control of a suitable gradient forming device. Thus, during polymerization the buffering groups forming the pH gradient are covalently attached and immobilized via vinyl bonds to the backbone of the polyacrylamide matrix.

Detection of proteins in polyacrylamide gels using an ultrasensitive silver staining technique

Polyacrylamide gel electrophoresis is a versatile and powerful tool for the analysis of biological samples and is capable of good separation and high resolution of complex protein mixtures. Although Coomassie Brilliant Blue R250 has proved ideal as a general protein stain for the more traditional applications of this method, current trends toward thinner gels, decreased sample loading (to improve resolution), and the recent developments of two-dimensional gel electrophoresis and peptide mapping techniques have necessitated increasingly sensitive detection methods. Electrophoretic separation of radioactively labeled proteins followed by autoradiography permits the detection of trace proteins (10(-4) to 10(-5)% of total protein) in a sample (1). However, problems inherent in radioactive methods include: (a) in vitro labeling may alter physical properties of proteins, and (b) in vivo experiments require excessively large quantities of isotopes that are prohibitively expensive in animals and unethical in human clinical studies. Alternative methods such as fluorescent staining (2) and heavy metal stains (3) are of less than, or at best of equivalent sensitivity to, Coomassie Brilliant Blue R250.

Two-Dimensional Electrophoresis Using Immobilized pH Gradients in the First Dimension

The high-resolution capacity of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) based on the method of O'Farrell (1) makes it the method of choice for the analysis of complex protein mixtures (2-4). In the standard procedure, cylindrical tube isoelectric focusing (IEF) gels are used. Unfortunately this system suffers from severe cathodic drift resulting in pH gradients that do not extend above pH 8, resulting in concomitant loss of basic proteins from 2-D maps. Gradients can be extended to pH 10 by special treatment of the glass IEF tubes (5) or by using a horizontal flat-bed IEF (5-7). In spite of the improvement in resolution of basic proteins that can be achieved with these procedures, difficulties are still associated with the first-dimension IEF gels as a consequence of the characteristic properties of the synthetic carrier ampholytes used to generate the pH gradients. These include problems of batch reproducibility of ampholytes, irreproducibility of separations, difficulty in control of pH gradient stability and shape (i.e., "pH gradient engineering"), and the possibility of artifacts caused by protein-ampholyte interactions.

Two-dimensional polyacrylamide gel electrophoresis using flat-bed isoelectric focusing in the first dimension

Electrophoretic techniques are, perhaps, the most important group of procedures for the separation and analysis of complex protein mixtures because of their high resolution capacity. This resolving power is maximized in high-resolution, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) based on the technique developed by O'Farrell (1). This methodology involves a combination of a first-dimension separation in cylindrical isoelectric focusing (IEF) gels containing 9M urea and 2% (w/v) of the detergent NP-40 with discontinuous gradient polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) in the second dimension. Detailed reviews of the theoretical basis, methodological variations, and applications of this technology can be found in refs. 2-5.

Computed tomography, management, and follow-up in infantile hemangioendothelioma of the liver in infants and children

Hepatic hemangioma (hemangioendothelioma) is a rare but most common benign vascular tumor of the pediatric age group. Prompt diagnosis and treatment prevent complications. Familiarity with various CT patterns should facilitate correct diagnosis of hemangioendothelioma of the liver in infants and children and avert angiography.

Fluorometer based multi-parameter analysis of phagocytic cell activation

Simultaneous measurements of the calcium rise, membrane potential change, and 90 degrees light scatter (shape change) responses exhibited by neutrophils upon activation, can be obtained with identical result as that obtained when independently performing each measurement. The putative intracellular mediator diacylglycerol depolarizes membrane potential and causes a decrease in light scatter. Leukotriene B4 causes a rise in calcium and a decrease in light scatter. The chemotactic peptide, N-formylmethionyl-leucyl-phenylalanine, causes a depolarization of membrane potential, a calcium rise, and a decrease in light scatter. The fura 2 measurements of intracellular free calcium indicate that the calcium concentration of unstimulated cells is much lower than previously thought based on quin 2 studies.

Is nursing a profession? Results of a Missouri study

This article examines the question of whether or not nursing is or should be a profession. The conclusion is based primarily on an analysis of what constitutes a profession and an empirical study of some nursing practices and attitudes. The analysis of professions recognizes three prominent models in sociology: trait, functional, and power or control. It bypasses these in favor of a "cluster concept," which asserts that the public has a number of expectations of an occupation before it will bestow the status of profession upon it. We then give an analysis of some of the results of the survey of a sample of Missouri registered nurses. The gist of the data is said to reflect the facts that these nurses think nursing is or should be a profession, but that other factors tend to show that nursing lacks the requisite cluster to substantiate the claim to be a profession. We conclude that nursing should perhaps not be a profession since it has been a bastion of the "ethics of compassion" in a world that is increasingly beset by an "ethics of competence."

Rapid commercial test for direct detection of group A streptococci in throat swabs

The Hybritech Strep A ICON was used for direct testing of 1016 throat specimens for group A beta-hemolytic streptococci. Both the test and culture were negative in 829 specimens (81.6%); both were positive in 164 cases (16.1%); the test was positive and culture negative in 9 cases (0.9%); and the test negative and culture positive in 14 cases (1.4%).

In vivo study of an antimicrobial surgical drape system

We performed a double-blind clinical study to determine the efficacy of nonwoven laparotomy drapes in which 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride, an antimicrobial agent, was chemically bonded to the absorbent reinforcement surrounding the fenestration. The reinforcement portion of the surgical drape that contained the fenestration was segmented into four identical-appearing sections, two on each side of the fenestration. One segment on each side was antimicrobial. The locations of the treated segments were randomly varied. At the end of each operation, test strips were removed. Bacteria were harvested from each segment by mechanical agitation. Bacterial CFU were counted. There were 110 surgical cases in the study, including clean, clean contaminated, and contaminated procedures. Data analysis divided the cases into two distinct groups. Group 1 was composed of 59 cases in which less than 30 total CFU was recovered from the four test samples. The average duration of surgery for this group was 1.8 h. Group 2 was composed of 51 cases in which bacterial recovery was in excess of 30 CFU per procedure (range, 30 to 25,000 bacterial CFU). The average duration of surgery was 3.3 h. Bacterial reduction in the treated strips was 84%. The most common organisms identified on the laparotomy drapes were Staphylococcus epidermidis, S. hominis, and Micrococcus luteus. This study demonstrated that the reinforcement of a laparotomy drape is a reservoir for potential pathogens. It demonstrated that an organosilicon quaternary ammonium antimicrobial agent covalently bonded to the reinforcement reduced the number of potential pathogens surrounding the surgical incision by 84%, independent of the size of the bacterial challenge.

Clinical trial of captopril (Aceten) in Indian patients with essential hypertension

ACE inhibitors are not available in India. Response to captopril in comparison with M-dopa was therefore seen in Indian hypertensive patients. A double blind randomized non-crossover study was carried out on 39 adult patients of either sex suffering from essential hypertension. Twenty-five patients included were resistant to earlier drug therapy. The remaining 14 were freshly detected hypertensive patients. Patients received either 150 mg/day captopril (Aceten) or 750 mg/day M-dopa in 3 equally divided doses every day for 30 days. The mean systolic and diastolic blood pressure in captopril (Aceten) group before starting drug therapy was 171 +/- 4.11 (mean +/- SE) and 111 +/- 0.22, respectively. At the end of therapy the systolic blood pressure was 132 +/- 1.86 and diastolic blood pressure was 84 +/- 1.36 mm of mercury. This fall in the blood pressure within the group was statistically highly significant (p less than 0.001). Similarly patients on M-dopa produced statistically highly significant fall in blood pressure (p less than 0.001) at the end of 4 weeks therapy. Initial systolic and diastolic blood pressure in both groups were comparable and, at the end of 2 and 4 weeks therapy, patients on captopril (Aceten) showed greater fall in both systolic (p less than 0.001) and diastolic (p less than 0.005) blood pressure than patients on M-dopa. None of the patients in the trial demonstrated clinically significant changes in the biochemical parameters. Six of nineteen patients on methyl dopa had side effects which are well known to this drug. None in the captopril showed any side effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-dose trimethoprim-sulfamethoxazole prophylaxis for cesarean section

Single-dose trimethoprim-sulfamethoxazole prophylaxis after clamping of the umbilical cord decreased the rate of endomyometritis in high-risk patients by 50% when compared with placebo. This drug combination may affect the normal flora of the cervix the least so that superinfections should be rare.

Interaction of influenza virus haemagglutinin with cell membranes

Influenza virus causes susceptible cells to undergo haemagglutination, haemolysis and oxygen radical formation. Each activity is the result of an interaction between the haemagglutinin (HA) glycoprotein and the cell plasma membrane, and appears to involve three discrete functions of the HA glycoprotein.

Permeability changes elicited by influenza and Sendai viruses: separation of fusion and leakage by pH-jump experiments

Permeability changes elicited in Lettre cells by influenza virus at pH 5.3 were maintained when the pH was shifted to 7.4. Permeability changes elicited by Sendai virus at pH 7.4 were maintained when the pH was shifted to 5.3. In each case permeability changes at the new pH were sensitive to inhibition by extracellular Ca2+. The time at which the pH was shifted was critical: if the shift was made prior to the onset of permeability changes, no subsequent changes occurred. It is concluded that the pH-sensitive event, namely virus-cell fusion, is related to the induction of permeability changes through attainment of some type of 'threshold' level of membrane damage.

Relationship of oxygen and glutathione in protection against carbon tetrachloride-induced hepatic microsomal lipid peroxidation and covalent binding in the rat. Rationale for the use of hyperbaric oxygen to treat carbon tetrachloride ingestion

CCl4 exerts its toxicity through its metabolites, including the free radicals CCl3. and CCl(3)00.. Oxygen strongly inhibits the hepatic cytochrome P-450-mediated formation of CCl3. from CCl4 and promotes the conversion of CCl3. to CCl(3)00.. Both these free radicals injure the hepatocyte by causing lipid peroxidation and binding covalently to cell structures. A reduced glutathione (GSH)-dependent mechanism can protect the liver microsomal membrane against CCl4-induced damage under aerobic conditions but not under anaerobic conditions (Burk, R.F., K. Patel, and J.M. Lane, 1983, Biochem. J., 215:441-445). Experiments were carried out using rat liver microsomes to examine the effect of O2 tensions found in the liver and of GSH on CCl4-induced covalent binding and lipid peroxidation. An NADPH-supplemented microsomal system was used. CCl4 or 14CCl4 was added to the sealed flask that contained the system, and after 20 min CHCl3 production, thiobarbituric acid-reactive substances (an index of lipid peroxidation), and covalent binding of 14C were measured. O2 tensions of 0, 1, 3, 5, and 21% were studied. Increases in O2 tension caused a fall in CHCl3 production, which indicated that it decreased CCl3.. GSH had no significant effect on CHCl3 production at any O2 tension. Lipid peroxidation and covalent binding of 14C fell progressively as O2 tension was increased from 1 to 21%. The addition of GSH decreased both lipid peroxidation and covalent binding, but did so better at the higher O2 tensions than at the lower ones. These results indicate that low O2 tensions such as are found in the centrilobular areas of the liver favor conversion of CCl4 to free radical products which cannot be detoxified by the GSH-dependent mechanism. They suggest that hyperbaric O2 might decrease free radical formation in the liver in vivo and promote formation of CCl(3)00. from CCl3.. This should result in diminished CCl4-induced lipid peroxidation and liver damage. Rats given CCl4 (2.5 ml/kg) were studied in metabolic chambers. Production of CHCl3 and ethane, the latter an index of lipid peroxidation, were measured. Rats in two atmospheres of 100% O2 produced much less CHCl3 and ethane than rats in air. This strongly suggests that hyperbaric O2 is decreasing free radical formation from CCl4 and/or promoting the formation of CCl(3)00. from CCl3.. These results provide the rationale for the use of hyperbaric O2 in the treatment of CCl4 ingestion.