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Biomedical subjects

M Anderson

Publications and source records attributed to M Anderson.

At least 397 records · Page 22Linked to original sources
PubMed1983

Ultrastructure of sensilla on the antennal pedicel of the brown planthopper Nilaparvata lugens Stal (Insecta: Homoptera).

Scanning- and transmission electron-microscope studies of the sensilla of the pedicel of Nilaparvata lugens have revealed an elaborate plaque organ and three structurally different types of trichoid hairs. Each plaque organ is innervated by 120-150 neurons arranged in groups. The porous sensory cuticle is folded into finger-like projections and is surrounded by protective non-sensory denticles. Trichoid sensilla differ in number of neurons, appearance of dendrites and arrangement of pores. Type I, innervated by 2 neurons, has pores along its length and is probably olfactory in function. Types II and III are innervated by one and five neurons, respectively, and the absence of pores along the hair shaft indicates a possible gustatory role. The importance of these sensilla is discussed with reference to the behaviour of this important insect pest.

Animals↗
PubMed1983

Mn ions pass through calcium channels. A possible explanation.

The divalent transition-metal cations Fe, Co, and Ni were used to test the hypothesis that Mn ions pass through calcium channels because Mn ions have a relatively low energy of hydration. The test ions were applied to the bath and comparisons were made of their effects on Ca or Mn spikes elicited from myoepithelial cells of the proventriculus of the polychaete worm Syllis spongiphila. Control experiments showed that (a) results obtained using deoxygenated solutions (required to stabilize Fe2+ ions) could be compared with those using solutions containing oxygen, and (b) the test cations did not measurably affect the electrical coupling between cells. Ca spikes were reversibly abolished by the test cations in the order of effectiveness: Fe (16.1 mM +/- 1.0, SE; n = 15) = Co (14.6 mM +/- 0.8; n = 27) less than Ni (8.3 mM +/- 0.7; n = 16). The test cations diminished Mn spikes by decreasing maximum rates of rise (Fe = Co less than Ni) and overshoot amplitudes (Fe less than Co less than Ni). The test cations also increased the current intensity required for Ca (Fe = Co less than Ni) or Mn spike initiation (Fe less than Co less than Ni). Since the energies of hydration of Fe, Co, and Ni increase stepwise from that of Mn, and the effectiveness of these ions in diminishing Ca and Mn spikes increased in the order Fe less than or equal to Co less than Ni, these data support the hypothesis that Mn ions pass through Ca channels because they shed waters of hydration relatively easily. An additional observation was that, at below-blocking concentrations, the test cations caused decreased duration of Mn spikes and increased duration of Ca spikes.

Action Potentials↗
PubMed1983

Nocardia asteroides recovery from a dog with steroid- and antibiotic-unresponsive idiopathic polyarthritis.

This report describes a fatal case of idiopathic polyarthritis in a dog that was partially responsive to vigorous immunosuppressive treatment. Synovial fluids were cultured for L-forms at the following stages of disease: (i) acute arthritic relapse, (ii) incomplete remission, and (iii) death. Nocardia asteroides UCD 1-581 was recovered from the L-form broth culture of the specimen taken during acute relapse, 5 weeks after inoculation, but not at any other stage of disease. Numerous conventional microbiological cultures were unproductive during all phases. Changes occurring in L-form plates included the formation of large irregular mineral deposits and many transferable bodies resembling pseudocolonies. Microscopic examination revealed the presence of many intracellular golden-brown granules and acid-fast bodies in macrophages of the lung and bronchial lymph node tissues. The granules are believed to be the variants embedded in calcium deposits similar to those which developed in the L-form cultures in vitro. Fluorescence of these acid-fast bodies with antibody specific for superoxide dismutase of N. asteroides GUH-2 and labeled anti-immunoglobulin G established their relationship to the isolate. The unrelenting course of disease and the persistence of N. asteroides as an L-form in this animal despite vigorous immunosuppression suggest that this organism plays a direct role in the etiology of this disease.

Adrenal Cortex Hormones↗
PubMed1983

Location and activity of ulcerative and Crohn's colitis by indium 111 leukocyte scan. A prospective comparison study.

A prospective blinded study comparing the indium 111 leukocyte scan to barium enema, colonoscopy, or surgery or a combination of these, was carried out in 15 patients (10 with active ulcerative colitis and 5 with active Crohn's colitis). Correlation of disease location to colonic regions between indium scan and other diagnostic studies was excellent in 11 instances, good in 2, and poor in 3. In 2 of the 3 studies where major disagreement occurred, the comparative barium enema was performed greater than 2 mo after the indium scan. Disease activity, estimated by the intensity of radionuclide uptake, was compared to clinical disease activity assessed by the Crohn's Disease Activity Index for both forms of colitis. The relative degree of inflammation estimated by the indium scan correlated well with the independent clinical assessment (correlation coefficient = 0.81). The indium 111 leukocyte scan appears to be an accurate, noninvasive method for assessing the extent and the severity of the inflammation in patients with acute ulcerative or Crohn's colitis.

Adolescent↗
PubMed1982

Intestinal obstruction and perforation caused by undigested Acacia sp leaves in langur monkeys.

During a 2-week period, 3 hanuman langurs (Presbytis entellus) died from severe fibrinopurulent and proliferative peritonitis. Partially digested plant material was identified in the necrotic abdominal debris of the 1st and 2nd langurs. In the 3rd, a phytobezoar that extended 17.5 cm distally from the pyloric area had caused a 1-cm perforation. Seven months later, surgery was performed on a douc langur (Pygathrix nemaeus) to remove 1 gastric and 2 intestinal phytobezoars composed primarily of undigested Acacia sp leaves. An analysis of Acacia sp leaves consumed by these langurs revealed a high cell wall concentration (40%, dry basis), with an exceedingly high proportion of this cell wall composed of indigestible lignin. It was concluded that the species of acacia (Acacia saligna and A longifolia) fed in these cases are inappropriate browse items for langurs.

Acacia↗
PubMed1982

Non-A, non-B hepatitis: a case report.

Ultrastructural changes in a liver biopsy obtained for diagnostic purposes from a patient with suspected non-A, non-B hepatitis were consistent with hepatitis and included dilatation and disaggregation of the endoplasmic reticulum, hepatocyte disarray, and variations in mitochondrial size. In addition, some foci of hepatocytes showed atypical cytoplasmic changes including intranuclear cytoplasmic pseudo-inclusions, consisting basically of invaginations of the cytoplasmic mass into the nucleus, glycogen deposits in the same nuclei, and frequently accumulations of fat droplets. The mitochondria were generally pleomorphic, and occasionally the mitochondrial cristae were arranged longitudinally. Dilatation, hypertrophy, and distortion of the Golgi complexes were found in affected hepatocytes. Similar ultrastructural changes have previously been reported in human hepatocellular carcinoma as well as in carcinomas of other tissues.

Cell Nucleus↗
PubMed1982

Factors affecting the distribution of lipoprotein lipase activity between serum and casein micelles in bovine milk.

The influence of mastitis and early lactation, and the effect of treating milk with heparin, blood serum and trypsin, on the proportion of lipoprotein lipase (LPL) activity in mild serum was investigated. The relative importance of milk serum LPL and LPL bound to micellar casein in promoting lipolysis was also examined. Colostrum contained LPL activity, 45% of which was found in the serum phase in samples obtained from the first milking post partum, but this value fell to 34% in samples taken 24 h later. The proportion of serum LPL was also increased in milks from quarters infected with Staphylococcus aureus, but not after overnight treatment of normal milk at 4 degrees C with 5% (w/v) blood serum or 2 microgram/ml trypsin. The addition of 5 microgram/ml heparin resulted in a consistent increase in serum LPL which varied between 14 and 50% of total milk LPL. Heparin did not release all the enzyme bound to casein micelles even after a second heparin treatment of resuspended micelles. Serum LPL was more effective in promoting lipolysis and was more responsive to blood serum activation than LPL bound to casein micelles. Lipolysis increased after heparin treatment but the increase was not related to serum LPL activity.

Animals↗
PubMed1982

Transforming growth factor(s) production enables cells to grow in the absence of serum: an autocrine system.

Kirsten murine sarcoma virus (KiMSV)-transformed rat-1, normal rat kidney (NRK), and BALB/c 3T3 cells are capable of continual growth in a serum-free medium supplemented with transferrin and insulin but with no exogenous mitogenic growth factors. Cells transformed by a mutant of KiMSV that is temperature sensitive for the maintenance of transformation grow in this medium at the permissive temperature only. At the nonpermissive temperature, growth is dependent upon the presence of serum-free conditioned medium from the transformed cells. Normal rat-1 cells are also dependent upon factors from the transformed cells for growth in this serum-free/mitogen-free medium. The serum-derived growth factors, epidermal growth factor, and fibroblast growth factor have no effect on the transformed cells, although epidermal growth factor can replace transforming growth factors produced by KiMSV-transformed cells for the growth of rat-1 cells. Growth of the transformed cells in serum-free medium at clonal densities is dependent upon the presence of conditioned medium collected from the same cells grown to high densities. These results show that (i) growth in serum-free/mitogen-free medium is a general property of KiMSV-transformed cells and (ii) growth of the transformed cells in this medium is dependent upon the presence of growth factors known to be produced by the cells, and they provide support for the hypothesis that serum-free growth of KiMSV-transformed cells is dependent upon ectopically produced growth factors.

Animals↗
PubMed1982

Automated nitrogen-washout methods for infants: evaluated using cats and a mechanical lung.

Infants with respiratory distress syndrome are treated with constant distending pressures to counter atelectasis and increase the functional residual capacity (FRC). However, FRCs are not monitored in these severely ill infants because present methods are impractical. We computerized N2-washout techniques for estimating the lung volume in these infants. The system has been evaluated using 1) a mechanical lung model and 2) small cats with normal and edematous lungs. Comparing the results of measured lung volumes with the fixed mechanical lung volumes yielded a correlation coefficient 0.996 (n=50). Decreasing the N2 gradient between initial N2 concentration and the washout medium from 0.79 to 0.10 did not affect the accuracy or reproducibility of measurements in the mechanical lung. For normal cats, comparing the results of N2-washout measurements of FRC with He-dilution values yielded a correlation coefficient of 0.921 (n=128); results from cats with pulmonary edema yielded a correlation coefficient 0.989 (n=80). We conclude that this computerized system is accurate, reproducible, and clinically acceptable for monitoring infants.

Animals↗