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Biomedical subjects

B Green

Publications and source records attributed to B Green.

At least 127 records · Page 7Linked to original sources
PubMed1990

Isolation and structure elucidation of a novel 5-kDa peptide from neurohaemal lobes of the corpora cardiaca of Locusta migratoria (Insecta, Orthoptera).

Two predominant peptides have been isolated from neurohaemal lobes of corpora cardiaca of 8000 adults of Locusta migratoria. Both peptides have been unambiguously characterized by automated peptide microsequencing and liquid secondary-ion mass spectrometry as a 50-residue peptide (5K peptide) and a 48-residue isologue (5K' peptide). Computer search of sequence data banks did not reveal any significant similarity with other identified proteins. The 5K peptides are remarkably rich in alanine residues (25%) and contain a stretch of five consecutive alanines. This structure suggests that these molecules could correspond to spacer peptides. This assumption is corroborated in the accompanying paper [Lagueux et al. (1990) Eur. J. Biochem. 187, 249-254] on the molecular cloning of the precursor protein which attributes to the 5K peptides a role analogous to that of the C peptides of insulins.

Amino Acid Sequence↗
PubMed1990

Application of electrospray mass spectrometry to the characterization of recombinant proteins up to 44 kDa.

Mass measurement by electrospray mass spectrometry (ESMS) is used as a rapid preliminary verification of the identity of various recombinant proteins ranging from 7 to 44 kDa with an accuracy of 0.01-0.03%. ESMS not only improves the speed but also the reliability of the protein structure determination when used in conjunction with other methods of protein analysis. Modifications of these large molecules, for example the loss of C-terminal amino acids, N-terminal acetylation, 2-mercaptoethanol addition to a cysteine, and trace formation of a covalent dimer (3%), are easily detected individually or in mixtures by mass measurement using ESMS; feats which would be very difficult to achieve using classical biochemical methods. As little as 1% of several structurally related protein contaminants have been identified in a 15 kDa recombinant protein preparation.

Amino Acid Sequence↗
PubMed1989

Tuberculous and granulomatous mastitis.

Granulomatous breast diseases are rare and may be indistinguishable clinically from carcinoma. Four cases illustrating the various modes of presentation and diagnostic difficulties are presented. Guidelines for management are suggested.

Adult↗
PubMed1989

Mass spectrometry analyses of recombinant hirudins (7 kDa).

The use of liquid secondary ion mass spectrometry (LSIMS) in the characterization of related recombinant 7-kDa peptides illustrates the adequacy of average mass measurement by scanning at low resolution. The difficulty in using the high-resolution technique in the case of poor LSIMS sensitive peptides is discussed, as well as the fact that it does not give, for these molecular weights, any real advantage. The average (or chemical) molecular weights of three recombinant hirudin molecules, hirudin variant 2 (rHV2, 6892.4 Da), hirudin variant 2-Lys47 (rHV2-Lys47, 6906.5 Da), and hirudin variant 2-Arg47 (rHV2-Arg47, 6934.5 Da), less than or equal to 10 micrograms each, have been measured with an accuracy less than or equal to 0.3 Da in the narrow-scan mode and less than or equal to 0.5 Da (from the protonated molecular ion) in the wide-scan mode within 10-15 min; this allows easy distinction of the three 65 amino acid proteins, which differ by a single amino acid. These three molecules could also be distinguished from one another in a mixture. Mass spectrometry and limited sequence characterization of several minor, similarly isolated peptides identified them to be N-terminal additions and/or C-terminal deletions of rHV2-Lys47. LSIMS analysis is consistent with there being no covalent dimer of rHV2-Lys47 as a narrow scan of the 7-kDa molecular ion cluster at high resolution shows it not to be a doubly charged ion.

Amino Acid Sequence↗
PubMed1989

Milk composition in the red-necked wallaby, Macropus rufogriseus banksianus (Marsupialia).

1. Milk samples were collected throughout lactation from 10 captive red-necked wallabies. 2. The milk solids content increased throughout lactation and was accompanied by major changes in the relative proportions of protein, lipid and carbohydrate. 3. The carbohydrate fraction consisted of oligosaccharides in the first half of lactation but changed subsequently to monosaccharides. 4. The quantitative and qualitative changes observed were similar to those recorded for other macropodids.

Animals↗
PubMed1989

Effects of time of dose in relation to food on the bioavailability of Theo-Dur Sprinkle at steady state in asthmatic children.

The effects of administration of Theo-Dur Sprinkle in the fasting state (phase A), 10 minutes before food (phase B), and immediately after food (phase C) were investigated in 12 children with asthma aged 5 to 9 years at steady state. The AUC during the dosing interval was significantly reduced in phases B and C compared with phase A, and bioavailability relative to the fasting state was reduced to 77% +/- 15% (range 61% to 104%) in phase B and 70% +/- 16% (range 40% to 103%) in phase C. The average plasma theophylline concentration during the dosing interval and Cmax were also significantly reduced in phases B and C compared with phase A. The morning predose plasma theophylline concentration in phase B was 22% lower than the predose concentration with Theo-Dur tablets taken 10 minutes before breakfast. The diurnal variation in predose plasma theophylline concentrations was increased from 28% in phase A to 63% in phase C. There was no significant difference in any parameter between administration 10 minutes before food and immediately after food.

Asthma↗
PubMed1989

Morphologic alterations in rat brain following systemic and intraventricular methotrexate injection: light and electron microscopic studies.

To determine the morphological substrate of acute methotrexate (MTX) encephalopathy, light and electron microscopic studies were performed on rat brains after short-term intraperitoneal (IP) and intraventricular (IV) injections of MTX. In both models, Alzheimer type II astrocytosis was the initial and major pathologic alteration seen by light microscopy. The neurons, oligodendrocytes, myelin and endothelial cells were relatively spared. Ultrastructural studies showed pleomorphism and condensation of mitochondria, membrane-bound vacuoles, prominent stacks of sparsely granular, rough endoplasmic reticulum and progressive hydropic swelling of astrocytic perikarya and their processes. The astroglial alterations were reversible after cessation of the drug but persisted for a longer time with repeated IP administration. Gastrointestinal complications and overall mortality were also greater with higher doses and increasing frequency of IP MTX injection. White matter necrosis was noted only after IV injection of high-dose MTX. The neuropathologic changes of MTX leukoencephalopathy can be replicated in an animal model by IV injection of the drug. The reversibility of the changes that were seen following IP administration correlates with the transient neurologic deficits observed in some patients after high-dose systemic MTX therapy. The initially selective astroglial effect suggests that astrocytes might be a target for MTX toxicity, although other central nervous system components may also be adversely affected by the drug.

Alzheimer Disease↗
PubMed1989

Phenotypical features of an unique Irish family with severe autosomal recessive osteogenesis imperfecta.

Severe Sillence type II/III Osteogenesis imperfecta (OI) is a lethal or severely crippling disease with either autosomal dominant or recessively inherited type I collagen mutations. Here we describe the detailed clinical features of a thin-ribbed OI variant with deformed limbs. The three consecutively affected children showed no genetic linkage with either of the two type I collagen genes, which implies that a novel mechanism causes this clinical phenotype. It can be prevented using ultrasound to diagnose affected foetuses.

Collagen↗
PubMed1988

Automated sequential trace enrichment of dialysates and robotics. A technique for the preparation of biological samples prior to high-performance liquid chromatography.

The development of the sample preparation process, the automated sequential trace enrichment of dialysates, in association with a cartesian robotic sampler is described. The system has been applied to the total automation of the preparation of biological samples and high-performance liquid chromatographic analysis. Concepts of the technique are reported together with an examination of its application to free and total analyte estimation. Examples of chromatographic separations obtained from the preparation of a variety of different analytes and sample materials are given.

Amino Acids↗
PubMed1988

Defective production of and response to IL-2 in acute human falciparum malaria.

Patients with acute Plasmodium falciparum malaria have defective cell-mediated immune responses to malaria-specific Ag (MA). This immunologic defect may partially explain the difficulty with which natural immunity to falciparum malaria develops and may have important implications for the efficacy of potential malaria vaccines in endemic areas. To investigate the basis of this immune defect, we have examined the capacity of PBMC from patients with acute falciparum malaria to produce IL-2 and to express I1-2R in response to Ag stimulation. The effect of exogenous IL-1 and IL-2 on lymphocyte proliferation was studied. Soluble IL-2R levels were measured in acute and convalescent sera. Our results showed that no detectable IL-2 was produced and no IL-2R were expressed by PBMC in response to MA during the acute infection. IL-2 production and IL-2R expression were also depressed when PBMC were exposed to streptococcal Ag. The specific immune defect was not reconstituted by the addition of graded doses of purified human IL-1 or IL-2 and could not be attributed to suppressor adherent cells. In contrast to the absence of IL-2 and cell-bound IL-2R, circulating soluble IL-2R was elevated in acute sera. These findings suggest that the lack of IL-2, through either a defect in its production or inhibition of its activity, may be the basis of the Ag-specific immune unresponsiveness in acute P. falciparum malaria.

Acute Disease↗