Effect of blood exchange on acyclovir clearance in an infant with neonatal herpes.
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Acyclovir↗
Biomedical subjects
D Johnson
Publications and source records attributed to D Johnson.
Thyrocalcitonin-containing cells in the Di George anomaly.
The Di George syndrome is an anomaly characterized by the complete or partial absence of derivatives of the third and fourth pharyngeal pouches often associated with defective development of the third, fourth, and sixth aortic arches leading to absence or hypoplasia of the thymus and parathyroid glands and to cardiovascular anomalies. The fifth pharyngeal pouch, often considered a part of the fourth pouch, gives rise to the ultimobranchial body (UB), which becomes incorporated into the thyroid gland and is thought to be the source of thyroid C cells. Robinson suggested that complete or partial absence of the UB should be considered a part of the Di George anomaly. To substantiate this theory, the thyroid glands of 11 patients with the Di George syndrome and 11 age-matched control infants were examined immunohistochemically using the immunoperoxidase technique for presence or absence of thyrocalcitonin (TC)-containing cells. Only three of 11 patients with the Di George syndrome had TC-containing cells in their thyroid glands (27 per cent), and nine of 11 control infants had these cells (82 per cent). It is concluded that thyroid C cell deficiency is present in most patients with Di George anomaly, suggesting a relationship between these cells and development of derivatives of the third through fifth visceral pouches. Furthermore, there is a spectrum of deficiency of thyroid C cells in these individuals comparable with the spectrum of partial to complete absence of third and fourth pharyngeal pouch derivatives regarding thymus and parathyroid glands. Immunostaining for TC of the lungs of all infants with the Di George syndrome and control infants revealed similar numbers of thyrocalcitonin-containing cells in both groups. Asynchronous development of thyroid and lung thyrocalcitonin-containing cells in those with the Di George syndrome favors the theory that the latter develop independently of derivatives of the third through fifth visceral pouches. This study further supports a neural crest origin of the Di George anomaly and strengthens the concept that the Di George anomaly is a neurocristopathy.
Calcitonin↗
Survival of red cells stored for 21 and 35 days in a non-di-(2-ethylhexyl)phthalate plastic container.
Whole blood and red cells were stored using citrate-phosphate-dextrose (CPD) and citrate-phosphate-dextrose-adenine (CPDA-1) anticoagulants in polyvinylchloride bags made flexible with di-(2-ethylhexyl)phthalate (DEHP) or tri-(2-ethylhexyl)trimellitate (TOTM) plasticizers. After storage the posttransfusion viability of these cells was tested in autologous donors. Cells stored in TOTM-plasticized film had a survival rate less than 75% when stored for 35 days, while other systems had a survival greater than this. When compared with the red cells stored in CPD-DEHP-plasticized film, the viability of whole blood and red cells stored in CPDA-TOTM showed a statistically significant decrease (p = less than 0.01). Therefore, red cell storage in TOTM-plasticized PVC with current anticoagulant should be limited to 21 days.
Benzoates↗
Myelin-associated glycoprotein in the central and peripheral nervous system of quaking mice.
The myelin-associated glycoprotein (MAG) was quantitated in the CNS and PNS of quaking mice and the levels compared to the levels of myelin basic protein (MBP) and 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) activity. In the brainstems of 36-day-old quaking mice, MBP, MAG, and CNPase were reduced to 12, 16, and 29% of control levels, respectively. In the sciatic nerves of the 36-day-old quaking mice, MBP and CNPase were 38 and 75% of control levels, respectively, whereas the concentration of MAG was unchanged or slightly increased. Similar quantitative results were obtained for the sciatic nerves and spinal roots of 7-month-old quaking mice. Immunoblots showed that the principal MAG band from the brainstems, sciatic nerves, and spinal roots of the quaking mice had a higher than normal apparent Mr. In addition, there was a minor component reacting with anti-MAG antiserum in the brainstems of the quaking mice that had a slightly lower Mr than control MAG and was not detected in the normal mice. The results for the quaking mice are compared with those from similar studies on other mutants with dysmyelination of the CNS and PNS.
2',3'-Cyclic-Nucleotide Phosphodiesterases↗
Molecular mechanism of mucin secretion: I. The role of intragranular charge shielding.
Mucus is an ubiquitous polymer hydrogel that functions as a protective coat on the surface of integument and mucosa of species ranging from simple animals (such as coelenterates) to mammals. The polymer matrix of mucus is made out of long-chain glycoproteins called mucins that are tangled together, forming a randomly woven, highly polyionic network (Lee et al., 1977; Verdugo et al., 1983). Mucin-containing granules, produced by mammalian goblet cells in vitro, undergo massive post-exocytotic swelling. Their swelling kinetics is similar to the swelling of condensed artificial polymer gels (Verdugo, 1984; Tanaka and Fillmore, 1979). We had proposed that mucins must be condensed in the secretory granule and expand by hydration during or after exocytosis (Verdugo, 1984; Tam and Verdugo, 1981). However, the polyionic charges of mucins prevents condensation unless they (the mucins) are appropriately shielded. The present experiments were designed to assert the presence of an intragranular shielding cation and its role in secretion. Giant mucin granules of the slug (Ariolimax columbianus) are released intact from mucus-secreting cells of the slug's skin. They burst spontaneously outside the cell, forming, upon hydration, the typical slug mucus (Deyrup-Olsen et al., 1983). We report here that these granules contain from 2.5 to 3.6 moles calcium/kg dry material, and that calcium is released from the granules immediately before the burst that discharges their secretory product. Therefore, we propose that calcium functions as a shielding cation of polyionic mucins, and that the bursting discharge of mucins from secretory granules must result from the release of calcium from the intragranular compartment.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Antineural antibodies in the serum of patients with amyotrophic lateral sclerosis.
Sera from 12 patients with amyotrophic lateral sclerosis (ALS) and 18 controls were screened for antineural antibodies using immunoblotting. No consistent differences were detected between ALS patients and controls, although antibodies to 52,000- and 70,000-dalton proteins in mouse spinal cord were somewhat more common in ALS sera. Antibodies to a protein of approximately 150,000 to 200,000 daltons were also evident. The 70,000- and 52,000-dalton proteins were detected in brain, cerebellum, and liver as well as spinal cord. Immunohistochemistry suggested antibody activity was directed at least in part to neurofilaments. While the antibodies to the 52,000- and 70,000-dalton proteins were more common in ALS than control sera (p less than 0.02 and less than 0.05, respectively), it is not clear from this initial study that this difference is of clinical or etiologic significance.
Amyotrophic Lateral Sclerosis↗
Effect of antidepressant and narcoleptic drugs on N-isopropyl p-iodoamphetamine biodistribution in animals.
N-isopropyl p-iodoamphetamine (IMP) demonstrates a high affinity for lung and brain during the first pass following intravenous injection. Its high brain affinity has been used to advantage for cerebral perfusion imaging, but the effects of drugs on IMP distribution could affect its utility. In this study, we determined the effects of the tricyclic antidepressant imipramine and the MAO inhibitors deprenyl and phenelzine on the biodistribution of IMP. We first determined the effect of loading dose and anesthesia on the biodistribution of IMP. In rats, biodistribution was not dependent on loading dose between 0.1 and 1.1 mg/kg. Anesthesia with thiopental and chloral hydrate depressed lung and brain IMP uptake. In rats, preloading doses of imipramine depressed lung uptake but did not result in increased brain IMP uptake; postloading doses of imipramine did not release IMP from the lung. In rabbits, simultaneous or postloading doses of imipramine resulted in release of IMP from the lung with an increase in brain activity. Both mixed A and B MAO inhibitors (phenelzine) and B selective MAO inhibitors (deprenyl) did not affect IMP distribution in rats. Based on the action of imipramine on IMP uptake and clearance in the lung, we postulate that IMP uptake and metabolism within the lung is related to the mixed function oxidase (MFO) system. As the lung is rich in the MFO system in humans, we would also predict from this study that IMP distribution in patients under antidepressant therapy would not be affected by either tricyclic or MAO inhibitor agents apart from the effect of these drugs on cerebral perfusion.
Amphetamines↗
Propidium binding to a ribonuclease-DNA complex: X-ray and fluorescence studies.
Propidium iodide, an antitumor compound, was diffused into crystals of a complex between RNase A and deoxytetraadenylate (dpA)4). This complex has four deoxyoligomers bound per protein molecule. A difference Fourier analysis at 2.9 A showed that the principal binding site for the propidium in the crystals was a hydrophobic depression on the side of RNase away from the active site and apparently involves methionine 13 and phenylalanine 8. Binding of propidium at this site produces small conformational changes that effect binding of nucleotides at the active site of the enzyme. Fluorescence titrations in the presence and absence of nucleotide inhibitors suggested that propidium iodide is a competitive inhibitor of the enzyme with a Kl of approximately 1 mM. No significant binding of propidium to the 16 nucleotides of single-stranded DNA associated with each protein molecule was observed.
Fourier Analysis↗
The impact of clinical specialists on length of stay.
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Aged↗
Model of protein conformation in the reversed-phase separation of interleukin-2 muteins.
Thirty muteins* of interleukin-2 were studied by reversed-phase high-performance liquid chromatography in a gradient mode. Values of the stoichiometry-factor Z [from Geng and Regnier, J. Chromatogr., 296 (1984) 15] varied over a 2.5-fold range for these proteins of similar molecular weight and composition. It is proposed that the more hydrophobic and/or more stable proteins have smaller values of Z while the larger Z-values correspond to a higher degree of protein unfolding during reversed-phase retention. The practical utility of this approach was demonstrated when these Z values were used to predict correctly a reversal in elution order for two closely related interleukin-2 muteins, when shallower gradients were used.
Amino Acids↗
The occurrence of polyenoic fatty acids with greater than 22 carbon atoms in mammalian spermatozoa.
Fatty acids with carbon chain lengths greater than 22 (VLCFA) have been detected in boar, ram, bull and human spermatozoa. Saturated and mono-unsaturated fatty acids were present in all spermatozoa but, except for human spermatozoa, polyenoic fatty acids were quantitatively the most important components. Marked differences in polyenoic fatty acid composition were observed. Whereas human spermatozoa contain predominantly di-, tri- and tetraenoic fatty acids with up to 32 carbon atoms, boar, ram and bull spermatozoa also contain pentaenoic and/or hexaenoic acids with up to 34 carbon atoms. Human and boar spermatozoa differ markedly from those of the ram and bull in that only n-6 series acids are present.
Animals↗
Expression and structure of the human NGF receptor.
The nucleotide sequence for the human nerve growth factor (NGF) receptor has been determined. The 3.8 kb receptor mRNA encodes a 427 amino acid protein containing a 28 amino acid signal peptide, an extracellular domain containing four 40 amino acid repeats with six cysteine residues at conserved positions followed by a serine/threonine-rich region, a single transmembrane domain, and a 155 amino acid cytoplasmic domain. The sequence of the extracellular domain of the NGF receptor predicts a highly ordered structure containing a negatively charged region that may serve as the ligand-binding site. This domain is conserved through evolution. Transfection of a full-length cDNA in mouse fibroblasts results in stable expression of NGF receptors that are recognized by monoclonal antibodies to the human NGF receptor and that bind [125I]NGF.
Amino Acid Sequence↗
High- beta plasmas in the PBX tokamak.
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Journal Article↗
Reversed-phase chromatography of interleukin-2 muteins.
Human recombinant interleukin-2 (IL-2) and related species have been characterized by chemical modifications, tryptic digestion, and cyanogen bromide digestion. The oxidation states of the cysteines and methionines in several IL-2 muteins have been determined. Reversed-phase high-performance liquid chromatography allowed us to distinguish the modifications in these muteins and to correlate retention behavior with their structure.
Amino Acid Sequence↗
Gene networks in development.
A model is presented for the formation of temporal and spatial patterns of cell types during the development of organisms. It is demonstrated that very simple random networks of interactions among genes that affect expression may lead to the autonomous development of patterns of cell types. It is required that the networks contain active feedback loops and that there is limited communication among cells. The only elements of the model, gene interactions, are specified by the DNA nucleotide sequences of the genes. Therefore, the model readily explains how the control of development is specified by the organism's DNA. In the context of this model, the formation of positional information and its interpretation becomes a single process.
Biological Evolution↗
Detection of a homologous series of C26-C38 polyenoic fatty acids in the brain of patients without peroxisomes (Zellweger's syndrome).
The brains of patients with inherited abnormalities in peroxisomal structure and function contain greatly increased proportions of a homologous series of unique polyenoic fatty acids with carbon chain lengths ranging from 26 to 38. Based on evidence by chemical ionization and electron impact mass spectrometry before and after catalytic hydrogenation, and argentation t.l.c., these lipids have been tentatively identified as 26:5, 28:5, 30:5, 30:6, 30:7, 32:5, 32:6, 32:7, 34:5 and 34:6 fatty acids. A further two fatty acids eluting at very high temperatures from gas chromatography columns have been tentatively identified on the basis of their chemical ionization mass spectra as 36:6 and 38:6 fatty acids.
Brain↗
Cyclic chemotherapy with cyclophosphamide, doxorubicin, and cisplatin plus vinblastine and bleomycin in advanced germinal tumors. Results with 100 patients.
One hundred patients with advanced mixed germ-cell tumors were treated with cisplatin, cyclophosphamide, and doxorubicin alternating with vinblastine and bleomycin (cyclic CISCAII/VBIV). The chemotherapy achieved an 89 percent continuous disease-free status (85 percent with chemotherapy, 4 percent with chemotherapy plus surgery). The mean follow-up duration for patients with continuous complete remission was 132 weeks (+/- 6.2), with a median of 126 weeks. Multivariate analysis using a stepwise logistic regression of prognostic variables revealed that a high serum level of the beta subunit of human chorionic gonadotropin (more than 50,000 mIU/ml) was of prognostic significance, followed by the Samuels staging criteria and extragonadal origin of disease. Thirty-two patients underwent exploratory surgery after they had had two courses of chemotherapy beyond the establishment of a stable mass and absent serum biomarkers. No viable cancer was found at exploration, and all patients remain alive and free of disease. The acute toxicity of the cyclic chemotherapy was formidable, but only one patient had a fatal complication. Thirty-six percent of the CISCAII courses and 44 percent of the VBIV courses were associated with leukopenic fever, and 5 percent of the CISCAII courses and 8 percent of the VBIV courses were associated with culture-positive infection. Long-term toxicity was unusual: bleomycin lung toxicity 1 percent, cardiac toxicity 1 percent. CISCAII/VBIV cyclic chemotherapy is superior to cisplatin, vinblastine, and bleomycin (PVB) chemotherapy; it results in a higher complete remission rate, a lower relapse rate, and a lower incidence of long-term complications. Patients with a high risk of failure of PVB chemotherapy (Samuels stage IIIB3 to IIIB5) or with extragonadal tumors should be treated with CISCAII/VBIV.
Adolescent↗
Morphometric analysis of the endocrine cell composition of rat pancreas following treatment with streptozotocin and nicotinamide.
Using immunohistochemistry and linear scanning, a morphometric analysis was made of the composition of the rat endocrine pancreas at sequential intervals after combined injections of streptozotocin (SZ) and nicotinamide (NA). One week after treatment, the volume of islet tissue was significantly higher than that of the corresponding, saline-injected controls, probably as the result of acute hyperplasia of insulin- and somatostatin-positive cells. However, at all time periods thereafter (6, 20, and 36 weeks), the drug-treated rats showed decreased islet volumes compared to controls. Analysis of aggregate (total) volumes of hormone producing cells at various time periods after drug treatment indicated that decreases in insulin (B-cell) volumes only partially accounted for the observed changes in total islet volume. There were, in addition, early decreases in glucagon (A-cell) and increases in somatostatin (D-cell) volumes. The results suggest that SZ/NA treatment caused limited islet B-cell destruction and transient changes in the proportions of islet A and D cells. Microscopic endocrine tumors were observed at 20 weeks, and both gross and microscopic tumors were observed 36 weeks after SZ/NA treatment. When islet and tumor tissues were included in computation, aggregate volumes of insulin and somatostatin-positive cells were markedly increased, with no significant changes in glucagon-positive cell volumes compared to controls, indicating that the tumors were rich in B and D cells, but poor in A cells. These results are discussed in relation to changes in glucose tolerance and serum insulin levels, and to islet cell volumes following treatment with a diabetogenic dose of streptozotocin alone.
Adenoma↗