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Biomedical subjects

S Anderson

Publications and source records attributed to S Anderson.

At least 451 records · Page 25Linked to original sources
PubMed1987

Subpopulations of mouse Lyt-2+ T cells defined by the expression of an Ly-6-linked antigen, B4B2.

The production and characterization of a rat mu,kappa monoclonal anti-mouse T cell subset antibody, B4B2, is reported in this paper. B4B2 typing of lymphoid tissues of commonly used inbred mouse strains revealed two types of reactivity patterns. They can be characterized as C57BL/6-like (B6-like) or C3H/He-like (C3H-like). Among B6-like strains, B4B2 recognizes 5 to 10% of spleen cells, 30 to 50% of bone marrow cells, and less than 2 to 3% of thymocytes. In C3H-like strains, B4B2 reacts with less than 1% of spleen cells, 2 to 8% of bone marrow cells, and less than 1% of thymocytes. B4B2 recognizes a T cell subset differentiation antigen expressed by B6-like strains but not by C3H-like strains. Typing of BXH recombinant inbred strains showed linked expression of B4B2 and the Ly-6 antigen. The expression of B4B2 antigen appears to be under codominant control as the median fluorescence distribution of B4B2+ cells in C57BL/6 was approximately twice that of (C57BL/6xC3H)F1. B4B2 was shown to react with approximately 40 to 50% of Lyt-2+ T cells and less than 1% of L3T4+ T cells. No staining of resting or activated B cells by B4B2 was detected. The ratio of B4B2+:Lyt-2+ cells was similar for resting T cells and activated T cells obtained from mitogen-stimulated cultures or mixed lymphocyte cultures. In neonatal spleen, substantially more B4B2+ than Lyt-2+ cells were found. With increasing age, however, a rapid decline in B4B2+ cells and a corresponding increase of Lyt-2+ cells was observed. By approximately 1 mo of age, the relative proportion of these subsets had reversed so that Lyt-2+ cells became more numerous than B4B2+ cells.

Age Factors↗
PubMed1987

Mutants of bovine pancreatic trypsin inhibitor lacking cysteines 14 and 38 can fold properly.

It is a generally accepted principle of biology that a protein's primary sequence is the main determinant of its tertiary structure. However, the mechanism by which a protein proceeds from an unfolded, disordered state to a folded, relatively well-ordered, native conformation is obscure. Studies have been initiated to examine the "genetics" of protein folding, with mutants of bovine pancreatic trypsin inhibitor (BPTI) being used to explore the nature of the specific intramolecular interactions that direct this process. Previous work with BPTI chemically modified at cysteines 14 and 38 indicated that transient disulfide bond formation by these residues contributed to efficient folding at 25 degrees C. In the present work, mutants of BPTI in which these cysteines were replaced by alanines or threonines were made and the mutant proteins were produced by a heterologous Escherichia coli expression system. At 25 degrees C in vitro, the refolding behavior of these mutants was characterized by a pronounced lag. However, when expressed at 37 degrees C in E. coli, or when refolded at 37 degrees or 52 degrees C in vitro, the mutant proteins folded readily into the native conformation, albeit at a rate somewhat slower than that exhibited by wild-type BPTI. These results indicate that, at physiological temperatures, BPTI lacking cysteines 14 and 38 can refold quantitatively.

Amino Acid Sequence↗
PubMed1987

A rapid method for the evaluation of diagnostic radioaerosol delivery systems.

The effective delivery (ED) in MBq/min of a 100 MBq/ml nebuliser solution was defined as the rate of delivery of droplets in the respirable size range (aerodynamic diameter below 3.3 micron) to the mouthpiece of the aerosol delivery system (ADS). Wasted delivery (WD) was defined as the rate of delivery of droplets above 3.3 microns. ED and WD were measured on four types of commercially available ADS. The aerosols were sampled at the mouthpiece of each system and droplet size distribution measured with a seven stage cascade impactor. The effect of ambient air humidity on the droplet size produced by the Cadema delivery system was also evaluated. The ED values ranged from 6 to 15 MBq/min and WD values from 0.01 to 15 MBq/min. Two ADS produced low ED and WD values (6.1-9.0 and 0.01-0.07 MBq/min, respectively) due to a low output, while another produced higher ED and WD values [11.3 +/- 0.2 (SD) and 15.4 +/- 0.5 (SD) MBq/min, respectively] due to a larger droplet size. The Cadema delivery system gave the optimum characteristic of high ED [13.9 +/- 0.8 (SD) MBq/min] and low WD [1.24 +/- 0.61 (SD) MBq/min] values. The mass median aerodynamic diameter (MMAD) of the Cadema ADS fell by 22% (P less than 0.01) as the ambient dilution air was dried from a high relative humidity (RH) (88%-100%) to a low RH (12%-17%). The variability of both MMAD and geometric standard deviation (sigma g) was increased with dry dilution air (P less than 0.01).

Aerosols↗
PubMed1987

Eye development in the normal and Pupoid foetus (pf/pf) mutant mouse.

Embryonic development of the mammalian eye has not been studied in such great detail as that of the avian eye, and preliminary observations have suggested that the sequence of events may differ. It is therefore likely that the relative importance of the cell and tissue interactions involved also differs and it would be interesting to compare these two systems. The pupoid foetus mutation in the mouse shows disruption of eye development due to abnormal epidermal properties and so the relative importance of individual events in triggering subsequent development can be studied by seeing what happens when the situation is modified in the mutant. The behaviour of the pupoid foetus epidermal cells in the interactive system of the eye may also help to further characterise the phenotype of the mutation.

Animals↗
PubMed1987

Comparison of loop diuretics in patients with chronic renal insufficiency.

Furosemide and bumetanide share a number of characteristics including reduced natriuretic effects in azotemic patients. It has been presumed that this condition affects each drug equally. Previous studies, however, suggest dissimilar pathways of delivery to their sites of action. Though not rigorously tested, this potential disparity might cause them to differ when used in azotemia. We, therefore, assessed the pharmacokinetic and pharmacodynamic characteristics of intravenously administered furosemide and bumetanide in ten adult patients with stable, chronic renal insufficiency (mean creatinine clearance = 14.1 +/- 2.0 ml/min/1.73 m2) in a randomized, cross-over study during controlled sodium intake. Our goals were to assess differences in diuretic effectiveness and in so doing to determine the dose required to produce a maximal response. The mean diuretic doses of 172 and 4.3 mg for furosemide and bumetanide, respectively (ratio = 40:1) were sufficient to produce a maximum response. Despite similarities in maximal fractional excretion of sodium (18.2 +/- 2.6% with furosemide vs. 19.4 +/- 4.5% with bumetanide, P = 0.687) demonstrating an equal tubular responsiveness to both drugs, overall response as quantified by cumulative natriuresis in the initial eight hour period was 52% greater with furosemide (108 +/- 17 vs. 71 +/- 7 mEq; P = 0.042). The difference in total excreted sodium was accounted for by a preserved nonrenal clearance of bumetanide (113 +/- 12 compared to 53 +/- 5 ml/min for furosemide, P = 0.001) which resulted in relatively less bumetanide in serum available to be delivered into the urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Reversing glomerular hypertension stabilizes established glomerular injury.

Munich-Wistar rats were studied 18 weeks following 5/6 renal ablation. In untreated group 1 rats maintained on standard chow containing 24% protein, sustained systemic and glomerular hypertension were associated with increasing proteinuria and widespread glomerular injury. In group 2, early treatment with the converting enzyme inhibitor enalapril prevented systemic and glomerular hypertension, and largely limited proteinuria and glomerular injury. Groups 3 and 4 received no therapy during the first eight weeks, during which they developed systemic hypertension and levels of proteinuria previously shown to be associated with significant glomerular sclerosis at this time point. Enalapril therapy begun at eight weeks in group 3 rats reversed systemic and glomerular hypertension, prevented a further rise in proteinuria, and limited glomerular lesions at 18 weeks relative to group 1. Reduction of dietary protein content to 12% at eight weeks in group 4 rats controlled glomerular but not systemic hypertension to near-normal levels, stabilized proteinuria values, and also limited glomerular lesions at 18 weeks compared to group 1. These studies support the view that glomerular hypertension is an essential hemodynamic derangement responsible for progressive glomerular injury. Furthermore, reduction of capillary pressure can arrest the progression of remnant glomerular injury even when therapy is delayed until glomerular injury is established.

Animals↗
PubMed1987

Collecting cancer registry data with a Cancer Patient Questionnaire.

Tumor registries provide a valuable source of treatment, survival, and epidemiologic data but have been faulted for incomplete and insufficient collection of data. An eight page, 38-item Cancer Patient Questionnaire (CPQ) was developed to collect more extensive information for the tumor registry. The CPQ identified significantly more patients with a family history of cancer than had previously been detected by chart review by the tumor registrar. The CPQ agreed with data collected by the tumor registry in 96% of cases for place of birth, 84% of cases for occupational history, 91% of cases for tobacco use, and 88% of cases for number of pregnancies or live births. The Cancer Patient Questionnaire is complete and easy to use and may replace the chart review in the collection of these data.

Data Collection↗
PubMed1987

Combined flow and absorption DNA measurements of [3H]TdR-labelled tumour cells. I. Studies of MCa-11 cells grown as tumours in vivo and as exponential cultures in vitro.

Flow cytometry of cellular DNA content provides rapid estimates of DNA distributions, i.e. the proportions of cells in the different phases of the cell cycle. Measurements of DNA alone, however, yield no kinetic information and can make it difficult to resolve the cell cycle distributions of normal and transformed cells present in tumour biopsy specimens. The use of absorption cytophotometry of the Feulgen DNA content and [3H]TdR labelling of the same nuclei provides objective criteria to distinguish the ranges of DNA content for G0/G1, S, and G2/M cells. We now report on a study in which we combined flow and absorption cytometry to resolve the cell cycle distributions of host and tumour cells present in biopsy specimens of MCa-11 mouse mammary tumours labelled in vivo for 0.5 hr with [3H]TdR. A similar analysis of exponential monolayer cultures, labelled for 5 min with [3H]TdR under pulse-chase conditions, revealed a highly synchronous traversal of almost all cells through the different phases of the cell cycle. Combination of the flow and absorption methods also allowed us to detect G2 tumour cells in vivo and a minor tumour stem-line in vitro, to show that these two techniques are complementary and yield new information when they are combined.

Absorption↗
PubMed1987

Atrial natriuretic peptide transcription, storage, and release in rats with myocardial infarction.

To study the role of atrial natriuretic peptide (ANP) in chronic heart failure, ANP synthesis, storage, and release were examined by measuring atrial ANP messenger ribonucleic acid (mRNA) levels and atrial and plasma ANP concentrations in rats with myocardial infarction produced by coronary artery ligation. Three groups were defined as the following: 1) controls, sham-operated, or operated, but noninfarcted; 2) moderate infarcts, involving 5-30% of the left ventricular circumference; and 3) large infarcts (greater than or equal to 30%). In addition, to determine a possible modulation by dietary Na intake on ANP levels in heart failure, plasma immunoreactive ANP (iANP) levels were measured in rats with and without infarcts given low, regular, or high Na intake for 2 wk, by which time all groups were in neutral balance. Plasma iANP levels varied directly with increasing infarct and atrial sizes, irrespective of Na intake. In contrast, atrial ANP concentration varied inversely with increasing infarct size. The ANP mRNA content index, a measure of total atrial ANP mRNA, was significantly increased in rats with large infarcts compared with control rats. These results indicate that in rats with myocardial infarction, the severity of left ventricular dysfunction, as inferred from infarct size, but not chronic Na intake, is the primary determinant of the extent of activation of the ANP system. Elevated circulating ANP levels are maintained through enhanced atrial synthesis and release. ANP may thus play an important role in the hemodynamic and renal adaptations to chronic heart failure.

Animals↗
PubMed1987

Elevated plasma atrial natriuretic peptide levels in diabetic rats. Potential mediator of hyperfiltration.

Infusion of atrial natriuretic peptide (ANP) increases the glomerular filtration rate (GFR), and ANP is released from cardiac myocytes in response to extracellular fluid volume expansion. Since diabetes mellitus is associated with glomerular hyperfiltration and volume expansion, we investigated the relationship between ANP and GFR in diabetic rats given insulin to achieve stable moderate hyperglycemia or normoglycemia. At 2 wk after induction of diabetes, moderately hyperglycemic diabetic rats exhibited elevations of plasma ANP levels averaging 281 +/- 28 pg/ml vs. 158 +/- 15 pg/ml in normoglycemic diabetic rats. In hyperglycemic rats, the GFR was also elevated on average to 2.24 +/- 0.28 ml/min as compared with 1.71 +/- 0.13 ml/min in normoglycemic diabetic rats. To test further the relationship between ANP and GFR in diabetes, moderately hyperglycemic diabetic rats were infused either with a specific ANP antiserum or with nonimmune serum. The infusion of specific ANP antiserum uniformly reduced the GFR on average from 2.38 +/- 0.1 ml/min to 1.60 +/- 0.1 ml/min, whereas the infusion of nonimmune serum was without effect. It is concluded that elevated endogenous ANP levels contribute to the hyperfiltration observed in early diabetes in the rat.

Animals↗
PubMed1987

Chronic glucocorticoid therapy amplifies glomerular injury in rats with renal ablation.

Functional and/or structural measurements were performed in eight groups of Munich-Wistar rats after five-sixths nephrectomy. Groups 1 and 5 received no therapy. Groups 2 and 6 received daily doses of methylprednisolone (MP). Groups 3 and 7 received MP plus the angiotensin I converting enzyme inhibitor (CEI), benzazepril. Groups 4 and 8 received CEI alone. Groups 1 through 4 underwent micropuncture study 2 wk after renal ablation. Untreated group 1 rats exhibited systemic hypertension and elevation of the single nephron glomerular filtration rate due to glomerular capillary hyperperfusion and hypertension. Administration of MP in group 2 resulted in comparable systemic hypertension, with further elevation of the single nephron glomerular filtration rate due to even higher values for glomerular perfusion and hydraulic pressure. Concurrent treatment with CEI in groups 3 and 4 controlled systemic and glomerular hypertension despite equivalent renal ablation and, in group 3, comparable doses of MP. Groups 5 through 8 were followed for 12 wk. Untreated group 1 rats demonstrated continued systemic hypertension, progressive proteinuria, and eventual glomerular sclerosis. Addition of MP in group 6 dramatically accelerated the development of proteinuria and glomerular sclerosis, while CEI (groups 7 and 8) afforded striking protection against disease progression. Thus, potent vasodilator glucocorticoids may amplify hemodynamically mediated glomerular injury, whereas control of systemic and glomerular hypertension prevents this undesirable consequence of chronic steroid therapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1987

The use of a drug utilisation index to monitor psychotropic drug use in hospitals.

A pilot study was undertaken to monitor the use of psychotropic drugs in a psychiatric hospital unit and a comparable acute medical unit together with their out-patient clinics, during a 2 month period. Both units served the same catchment area. Using the DDD (defined daily dose) for each class of drug, an index was calculated as an indicator of usage. An index figure of less than one indicated that each patient received on average less than the DDD, whereas an index greater than one showed that each patient received an average daily dose greater than the DDD. Other patient information collected included age, sex, length of time on drug, length of admission and the number of different psychotropic drugs received during admission.

Adult↗
PubMed1987

Bile acid metabolism during development: metabolism of lithocholic acid in human fetal liver.

The metabolism of [24-14C]lithocholic acid was studied in the microsomal fraction of fetal human liver homogenates. Fetal livers were obtained at legal abortions performed between wk 14 and 24. Product formation was analyzed by thin-layer chromatography, liquid chromatography, and gas chromatography-mass spectrometry. From wk 14 lithocholic acid was hydroxylated in several positions. Hyodeoxycholic acid (3 alpha,6 alpha-dihydroxy-5 beta-cholanoic) and 1 beta,3 alpha-dihydroxy-5 beta-cholanoic acid were identified among the products. The 3 beta-isomer of the former acid, 6 alpha-hydroxy-3-oxo-5 beta-cholanoic acid and a 2-hydroxylithocholic acid were tentatively identified. Two other metabolites carried a hydroxyl group in an unknown position, one of them probably at an angular methyl group. The highest total conversions per mg of microsomal protein were obtained with preparations from 18 wk fetuses. The results are discussed with particular reference to the role of lithocholic acid in fetal hepatotoxicity.

Bile Acids and Salts↗
PubMed1987

Therapeutic implications of converting-enzyme inhibitors in renal disease.

Micropuncture and morphological studies were performed in three protocols assessing the renal hemodynamic and structural effects of angiotensin I-converting enzyme inhibitors (CEIs) in the progression of glomerular injury. In protocol I, rats were subjected to 5/6 renal ablation and received no therapy, enalapril (CEI), or triple-drug therapy (TRX) for 12 weeks. Control of systemic and glomerular hypertension with CEI resulted in prevention of glomerular capillary hypertension and protection against glomerular injury. Despite equivalent control of systemic BP, failure of TRX to control glomerular hypertension was associated with no protection against eventual proteinuria and glomerular sclerosis, values for these indexes being as abnormal as in rats receiving no therapy. In protocol II, rats were again subjected to 5/6 renal ablation and followed for 18 weeks. Early institution of CEI soon after ablation again prevented systemic and glomerular hypertension and largely limited glomerular injury. In a third group, enalapril therapy was delayed for 8 weeks after ablation until hypertension and proteinuria were established. Late institution of CEI resulted in prompt reduction in systemic and glomerular capillary hypertension and stabilization of glomerular disease. In protocol III, CEI was administered to normotensive, moderately hyperglycemic diabetic rats. A modest, 20-mm Hg reduction in systemic arterial pressure was associated with the normalization of glomerular capillary pressure and a striking reduction in the development of albuminuria and glomerular injury. These studies suggest that CEI effectively prevent glomerular capillary hypertension and thereby afford protection against glomerular injury in diverse models of progressive renal disease.

Angiotensin-Converting Enzyme Inhibitors↗