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Biomedical subjects

T Marshall

Publications and source records attributed to T Marshall.

At least 127 records · Page 7Linked to original sources
PubMed1994

Parathyroid hormone-related protein gene expression in invasive cervical tumors.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) is the main tumor-derived factor responsible for the hypercalcemia of malignancy. METHODS: Using a polyclonal serum to the 37-67 region of PTHrP, and 35S-labeled riboprobes, the authors investigated the cellular expression of PTHrP mRNA and peptide in formalin fixed, paraffin embedded sections from 16 invasive cervical tumors. In addition, the relationship among the histologic cell type, degree of differentiation, pattern of invasion, and tumor expression of PTHrP were examined. RESULTS: PTHrP mRNA and peptide were identified in 10 of 10 and 16 of 16 tumors examined, respectively. Overall strong mRNA expression with moderate to intense intracellular staining for peptide was associated, with adenosquamous carcinoma displaying a spray pattern of invasion. CONCLUSION: PTHrP mRNA and peptide were observed in all cervical tumors studied. Despite their high frequency of expression of PTHrP, cervical tumors seldom give rise to humoral hypercalcemia of malignancy, but the autocrine/paracrine effects of PTHrP may be important in the growth and dedifferentiation of the malignant cell population.

Carcinoma, Adenosquamous↗
PubMed1994

Electrophoretic analysis of cat parotid saliva in response to parasympathetic stimulation or infusion of bethanechol.

The protein constituents of cat parotid saliva evoked by parasympathetic stimulation or the infusion of bethanechol have been compared by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The SDS-PAGE patterns were highly reproducible for an individual cat and revealed up to 30 polypeptide bands in microlitre volumes of unconcentrated saliva. Only minor and predominantly quantitative differences were detected in the salivary protein composition of different cats. SDS-PAGE demonstrates quantitative rather than qualitative changes in the protein composition of saliva evoked in response to different stimuli. The latter included preliminary observations on the effect of vasoactive intestinal peptide (VIP) on the bethanechol-evoked response.

Animals↗
PubMed1994

Diaspirin crosslinked hemoglobin (DCLHb): bioanalytical studies in swine.

These studies were a part of preclinical safety and efficacy studies of DCLHb. Their purpose was to analyze the characteristics of DCLHb during circulation, and the distribution of iron following the administration of DLCHb to swine. Swine were dosed (2 g/kg) with 10 g/dL DCLHb, infused intravenously at a rate of 1 mL/kg/min. Blood samples were collected up to 48 hours post-infusion for analysis. Tissue samples were obtained for iron determination. The data collected showed that the concentration of DCLHb in the plasma gradually decreased, while the concentration of methemoglobin remained low and essentially constant. The oxygen binding characteristics and stability of the crosslink were preserved following infusion, indicating that the DCLHb continued to function as an effective oxygen carrier. Iron concentrations in the liver and kidneys increased as expected, but plasma levels of iron did not saturate the iron binding capacity of transferrin, inferring a controlled process for the release of iron.

Animals↗
PubMed1994

Analysis of snake venoms by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional electrophoresis.

The protein composition of snake venom has been analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE) with comparison of our simplified Tris/glycine/SDS (TGS) method with a commercial Tris/Tricine/SDS (TTS) gel system. SDS-PAGE suggests differences between species and similarities between related species but 2-DE indicates that the protein composition of the venoms is highly complex. The TTS system improves resolution upon 2-DE but our simplified TGS method is optimal for silver staining which, contrary to previous reports, enhances detection 100-fold.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1993

Electrophoretic analysis of stimulated cat parotid saliva.

The proteins of parasympathetically stimulated cat parotid saliva were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE). SDS-PAGE revealed up to 30 polypeptide bands in microliter volumes of unconcentrated saliva. The patterns were highly reproducible and characterized by prominent bands of M(r) 57,000, M(r) 30,000 and M(r) 15,000. The major protein (M(r) 30,000) appeared as a dimer (M(r) 60,000) when electrophoresed under non-reducing conditions but dissociated into its monomeric form when the SDS concentration of the denatured samples was increased from 1 to 5%. This indicates a noncovalent association. The protein patterns of saliva from different cats differed slightly but sequential samples from the same cat (collected during 90 min of stimulation) showed little change in protein pattern apart from a fall in total protein content. Following 2-DE, the major protein (M(r) 30,000) appeared as a complex array of at least eight spots in two tiers (pI 5.2-6.2; M(r) 28,000 and 32,000). The characteristics of this protein are discussed with reference to allergy to cats.

Animals↗
PubMed1993

Bradford protein assay and the transition from an insoluble to a soluble dye complex: effects of sodium dodecyl sulphate and other additives.

The addition of sodium dodecyl sulphate (SDS) (0.0015-0.006%), phenol (0.25-0.5%) or sodium hydroxide (0.025-0.1 M) to the Bradford dye reagent does not improve the solubility of the Coomassie blue-protein dye complex. Centrifugation of the assay tubes, 10 min after the addition of reagent, results in complete loss of colour yield as indicated by the absorbance (A595) of the recovered supernates. At protein-concentrations above the working range of the assay, centrifugation indicates a transition from an insoluble to a soluble protein-dye complex. This transition is characteristic of an individual protein and is influenced by assay modification. Low protein concentrations appear to provide nucleation sites for precipitation of Coomassie blue whilst higher protein concentrations increase its solvation. A soluble dye chromophore is only formed above the working range of the assay indicating that precipitation of the dye by protein contributes to the assay mechanism.

Centrifugation↗
PubMed1993

Pregnancy associated osteoporosis.

OBJECTIVE: Previous literature reports have suggested that osteoporosis associated with pregnancy is a rare event. We have examined the prevalence of this condition and compiled data on the largest group of such patients in the literature. PATIENTS AND DESIGN: With the help of the National Osteoporosis Society 35 women with pregnancy associated osteoporosis were identified. These women were matched with a control group from our already established computer data bank for age, weight, height and calcium status. Detailed questionnaires were sent to the osteoporotic sufferers enquiring about their present condition, past medical and drug history, and their menstrual, lactational and obstetric histories. They were also asked to complete a detailed dietary history to establish their calcium status. A questionnaire was also completed by the parents of these women and the parents of the control group, asking specifically about fracture history. RESULTS: Twenty-nine women had idiopathic osteoporosis associated with pregnancy, while in six, the condition may have resulted from drug therapy or associated diseases. Pain occurring late in the first full term pregnancy was the most common presentation. The natural history was for the condition to improve with time. There was a significantly higher prevalence of adult related fractures (P < 0.02) occurring at an earlier age in the mothers of these women compared to a control population. CONCLUSION: We have identified 35 women who have developed osteoporosis during or shortly after pregnancy and in only six of them could a recognized underlying cause be suggested. These findings would suggest that idiopathic osteoporosis associated with pregnancy may be more common than the current literature suggests. The higher prevalence of fractures in the mothers of our population compared to controls raises the question of a possible associated genetic factor in the aetiology of this condition.

Adult↗
PubMed1993

Multiple acyl-coenzyme A dehydrogenation disorder responsive to riboflavin: substrate oxidation, flavin metabolism, and flavoenzyme activities in fibroblasts.

Multiple acyl-CoA dehydrogenation disorders result from generalized defects in intramitochondrial acyl-CoA dehydrogenation. Fibroblasts from a riboflavin-responsive multiple acyl-CoA dehydrogenation disorder patient catabolized 14C-butyrate, -octanoate, and -leucine normally after culture in riboflavin-supplemented medium (2 mg/L). After culture in riboflavin-depleted medium (< or = 1.4 micrograms/L), his cells oxidized the same substrates poorly at 20 to 33% of control (p < 0.05). Patient cells incubated in a wide range of D-[2-14C]riboflavin concentrations (3, 31.4, and 100 micrograms/L) synthesized 14C-flavin mononucleotide and 14C-flavin adenine dinucleotide (FAD) normally and had normal cytosolic 14C-flavin mononucleotide and 14C-FAD contents, which argues against defects in cellular riboflavin uptake and conversion to flavin mononucleotide and FAD. After culture in 31.4 micrograms 14C-riboflavin/L for 2 wk, 14C-FAD specific radioactivities plateaued and were similar in patient and control cells. However, culturing these uniformly labeled cells in riboflavin-depleted medium for 2 wk lowered the patient's cellular 14C-FAD content to only 23% of control levels. Similarly, after incubation in low 14C-riboflavin concentrations (4.4 micrograms/L), the patient's mitochondrial 14C-FAD content was only 51% of control after 1 h and 29% of control at 4 h. After a 4-h incubation in a high physiologic concentration of 14C-riboflavin (31.4 micrograms/L), which raised the patient's cellular 14C-FAD levels 3- to 4-fold, his mitochondrial 14C-FAD content rose to normal; control values did not change. We also investigated possible defective FAD binding to flavoenzymes essential for acyl-CoA dehydrogenation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acyl Coenzyme A↗