PubMed Health⌕ Search

Biomedical subjects

F J Wilson

Publications and source records attributed to F J Wilson.

At least 19 recordsLinked to original sources
PubMed1992

The effects of nerve growth factor and dibutyryl cyclic AMP on cytoskeletal densities in cultured sensory ganglia.

The effects of nerve growth factor (NGF) and dibutyryl cyclic AMP (DBC) on the density of cytoskeletal structures in cultured dorsal root ganglia were examined using morphometric techniques. After 24 hr in culture, NGF-treated neurites were longer than either DBC-treated or control neurites. At 48 hr, neurites produced in response to NGF and DBC were of equivalent length, while controls were considerably shorter. Comparison of electron micrographs of neuritic profiles revealed some differences of area and cytoskeletal density between treatment groups. Morphometric analysis was used to determine these differences under several growth conditions, at various rates of elongation and at different neurite lengths. As shown by analysis of variance, both NGF-treated and control neurites tapered in diameter at 48 hr in vitro, while DBC-induced neurites increased in area. An increase in cytoskeletal density for all treatment groups indicated that density was not always correlated with changes in area. An increased density of microtubules as compared to neurofilaments was seen at 24 hr, with equal densities of both cytoskeletal elements present after 48 hr in vitro. Comparisons between individual groups of data indicated that NGF-treated neurites relied primarily on microtubular density at 24 hr in vitro, when NGF induced longer, faster growing neurites. At 48 hr, there was an increase in neurofilaments proximal to the explant in the presence of DBC, implying that DBC may cause increased synthesis and/or transport of these structures. A comparison of microtubule to neurofilament ratios indicated that at 24 hr, there was always a greater density of microtubules. However, after 48 hr, neurofilament density increased such that there were equivalent densities of both cytoskeletal elements, possibly due to the overall increase in length observed in each treatment group. These data imply that 1) neurites with different rates of elongation may exhibit differences in cytoskeletal density; 2) neurites of equivalent lengths may be of differing stabilities; 3) NGF and DBC produce neurites with different cytoskeletal densities, implying divergent mechanisms of neurite induction; 4) the presence or absence of NGF may be partially responsible for variations in cytoskeletal densities observed between peripheral and central processes of DRG during development.

Animals↗
PubMed1992

Liposome-entrapped antifibrotic agent prevents collagen accumulation in hypertensive pulmonary arteries of rats.

We studied the therapeutic efficacy of an intravenously injected antifibrotic agent encapsulated in liposomes on inhibiting collagen accumulation in hypertensive blood vessels. cis-4-Hydroxy-L-proline (cHyp) in liposomes was injected into rats exposed to 10% O2, and drug effect was evaluated by measuring right ventricular pressure and hydroxyproline content of the pulmonary artery. Right ventricular pressure was 11 +/- 1 mm Hg (mean +/- SEM) 5 days after a single intravenous injection of 200 mg/kg cHyp in liposomes compared with 14 +/- 1 mm Hg in rats injected with empty liposomes; hydroxyproline content was also reduced by cHyp treatment (87 +/- 6 versus 107 +/- 7 micrograms per vessel) (p less than 0.05 for both, n = 6-9). Injections of cHyp in liposomes every 5 days partially prevented hypertension and vascular collagen accumulation during a 3-week exposure to hypoxia, and the dose required was one tenth the dose of unencapsulated cHyp. Therapeutic doses of cHyp in liposomes injected for 6 months affected tensile properties of main pulmonary artery and aorta, but there were no apparent histological effects on other organs. Liposomes injected intravenously were identified in pulmonary artery endothelial cells. The prolonged effect of a single injection of cHyp in liposomes may be due to uptake of the liposomes by the endothelium. Liposome delivery of drugs to the arterial wall may be useful in the study and treatment of hypertensive vascular disease.

Animals↗
PubMed1991

Twice-daily tapering dexamethasone treatment during cranial radiation for newly diagnosed brain metastases.

Twenty evaluable patients with newly diagnosed brain metastases underwent treatment with a novel dose/schedule of dexamethasone aimed at reducing steroid toxicity during palliative radiation therapy. All patients received twice daily dexamethasone starting at 8 mg bid for four days then 4 mg bid for four days then 2 mg bid until the last day of radiation therapy. The radiation prescriptions were not standardized varying from 2000 cGy/5 fractions to 5800 cGy/29 fractions. Fourteen patients received dexamethasone for a minimum of 24 hours before their first radiation treatment and 7 (50%) experienced improvement in neurologic symptoms/signs prior to starting radiation treatments. Fourteen patients completed the planned course of radiation and dexamethasone. Only 1 patient needed to restart dexamethasone within 30 days of finishing radiation because of steroid reversible neurologic deficits. Steroid toxicity was mild including hyperglycemia (1), candida esophagitis (1), steroid pseudorheumatism (2), peripheral edema (1) and steroid withdrawal syndrome (1). Only two toxic events were recorded in patients receiving steroids less than 21 days. Twice daily dexamethasone appears to provide good clinical results with minimal morbidity.

Administration, Oral↗
PubMed1989

Neuropeptide Y-containing nerves in rat gonads: sex difference and development.

The objectives of the present study were 1) to evaluate for a sex difference in innervation of adult rat gonads by neuropeptide Y-immunoreactive (NPY-I) nerves and 2) to examine the development of innervation of rat gonads by NPY-I nerves during the fetal and neonatal periods. With fluorescence immunocytochemistry, NPY-I nerves were profuse in adult ovarian tissues. Ovarian blood vessels were particularly well innervated by NPY-I nerves, and nerves were also detected in interstitial gland tissues. No nerves were found within the testis, and NPY-I nerves were only rarely located within the tunica albuginea. During fetal life, ovaries were devoid of NPY-I nerves; however, nerves were visualized within the connective tissue immediately peripheral to the ovary on fetal Day 22. As early as postnatal Day 2, NPY-I nerves were observed in connective tissue septa of the developing ovary. By postnatal Day 12, NPY-I nerves surrounded developing follicles and blood vessels of the ovarian cortex. In the developing testis after postnatal Day 5, NPY-I nerves were limited to the tunica albuginea and surrounding large subcapsular blood vessels. Structures within the testis lacked innervation by NPY-I nerves. These anatomical studies suggest that NPY-I nerves are absent in the gonads during fetal life and grow into the ovary and not the testis during the perinatal period and that NPY-I nerves may play a role in the functioning of the rat ovary, but may not be important in control of testicular function.

Animals↗
PubMed1987

Calmodulin-dependent phosphatases of PC12, GH3, and C6 cells: physical, kinetic, and immunochemical properties.

Calmodulin-dependent phosphoprotein phosphatase (CaMDP) activity has been found in each of three cultured cell lines: rat pheochromocytoma (PC12), glioma (C6), and pituitary adenoma (GH3) cells. These CaMDP activities bind to immobilized calmodulin in the presence of Ca2+ and are eluted by EGTA. Sucrose density centrifugation revealed that the phosphatase activities exhibited sedimentation coefficients of 4.37, 4.23, and 4.59 for proteins derived from C6, GH3, and PC12 cells, respectively. The Stokes radii measured for the PC12 and C6 activities were 41.8 and 40.0 A, respectively. The estimated molecular weights calculated for the enzymes from these data are 79,100 and 72,200. The phosphatase activities required the presence of divalent cations such as Ca2+ or Mn2+ for expression of activity, which was optimal only in the presence of calmodulin. The apparent Km for phosphorylated myelin basic protein substrate was 8 microM. Affinity-purified antibodies to the B subunit of bovine brain CaMDP were found by immunoblot (Western blot) to cross-react with a single protein among proteins extracted from PC12, C6, and GH3 cells that had been resolved by two-dimensional electrophoresis. In each case, the cross-reacting protein exhibited an Mr of 16,000 and an isoelectric point of 4.7, values virtually identical to those reported previously for the B subunit of bovine brain CaMDP (sometimes called calcineurin). This cross-reacting protein was found among cellular proteins eluted from immobilized calmodulin by EGTA. Immunocytochemical localization of the cross-reacting protein in undifferentiated PC12 cells or in cells differentiated in response to nerve growth factor revealed its presence diffusely throughout the cytoplasm. These experiments support the contention that each of these cell lines contains a calmodulin-regulated phosphatase homologous physically and kinetically, and immunologically related to bovine brain CaMDP.

Adenoma↗
PubMed1986

Improved immunoelectron microscopic method for localizing cytoskeletal proteins in Lowicryl K4M embedded tissues.

We have modified the Lowicryl K4M low-temperature dehydration and embedding procedure for immunoelectron microscopy to provide improved ultrastructural detail and facilitate the localization of actin and tubulin in isolated rat adrenocortical cells, chick spinal cord with attached dorsal root ganglia (SC-DRG), and cultured dorsal root ganglia (DRG). Cells and tissues were fixed for immunocytochemistry either in a mixture of 2% paraformaldehyde and 0.25% glutaraldehyde (0.1 M PIPES buffer, pH 7.3) or in a mixture of 0.3% glutaraldehyde and 1.0% ethyldimethylaminopropylcarbodiimide (0.1 M phosphate buffered saline, pH 7.3). Dehydration was in ethanol at progressively lower temperatures to -35 degrees C. Infiltration at -35 degrees C was followed by ultraviolet polymerization at -20 degrees C. Comparable samples were fixed in glutaraldehyde and osmium tetroxide and embedded in Epon 812 or Epon-Araldite. Post-embedding immunostaining of thin sections utilized commercially available monoclonal antibodies to tubulin and actin followed by the protein A-gold technique (Roth et al., Endocrinology 108:247, 1981). Actin immunoreactivity was observed at the periphery of mitochondria and between mitochondria and lipid droplets in rat adrenocortical cells and at the periphery of neuronal cell processes of SC-DRG. Tubulin immunoreactivity was associated with microtubules throughout neurites of cultured DRG. Our modified technique allows preservation of ultrastructural details as well as localization of antigens by immunoelectron microscopy.

Actin Cytoskeleton↗
PubMed1985

Quantitative deposition of ultrafine stable particles in the human respiratory tract.

Theoretical models of particle deposition in the respiratory tract predict high fractional deposition for particles of less than 0.1 micron, but there are few confirming experimental data for those predictions. We have measured the deposition fraction of a nonhygroscopic aerosol in the human respiratory tract. The aerosol had a count mean diameter of 0.044 micron SD of 1.93, as measured with an electrical aerosol analyzer, and was produced from a 0.01% solution of bis(2-ethylhexyl) sebacate using a condensation generator. Subjects inhaled the aerosol using a controlled respiratory pattern of 1 liter tidal volume, 12/min. Deposition was calculated as the difference in concentration between inhaled and exhaled aerosol of five size fractions corrected for system deposition and dead-space constants. Three deposition studies were done on each of five normal male volunteers. Means (+/- SE) for the five size fractions were 0.024 micron, 0.71 +/- 0.06; 0.043 micron, 0.62 +/- 0.06; 0.075 micron, 0.53 +/- 0.05; 0.13 micron, 0.44 +/- 0.04; and 0.24 micron, 0.37 +/- 0.06. These data demonstrate that deposition of inhaled particles in the 0.024- to 0.24-micron size range is high and increases with decreasing size. These observations agree with and validate predictions of mathematical models.

Adult↗
PubMed1985

Sleep apnea and the Arnold-Chiari malformation.

We present a polysomnogram-documented report of central sleep apnea (427 events) and moderately severe decreases in arterial oxygen saturation (to 81%) associated with the Arnold-Chiari malformation (ACM). Daytime hypersomnolence and other symptoms had significantly impaired our patient's work performance. After surgical correction of the ACM, there was marked improvement in symptomatology. A post-surgery polysomnogram revealed marked improvement in the number of central apneas (74 events) and only mild decreases in oxygen saturation (to 94%).

Arnold-Chiari Malformation↗
PubMed1984

Concentration and particle size distribution in smoke from marijuana cigarettes with different delta 9-tetrahydrocannabinol content.

Particle size and mass concentration are important determinants of site and quantity of respiratory tract deposition of aerosols. Particle concentrations and size distributions of smoke from marijuana cigarettes with different concentrations (as measured in the marijuana leaf) of delta 9-tetrahydrocannabinol (delta 9-THC) were measured using a single particle aerodynamic relaxation time (SPART) analyzer. The SPART analyzer measures aerodynamic diameter of single suspended particles at a rate of 3000/min. Cigarettes were smoked using a 35-cc, 2-sec puffing device attached to a diluter; dilution and analysis were completed within 4 sec of puff generation. The size distribution of smoke from all marijuana cigarettes was similar to that for tobacco cigarettes, ranging from 0.35 to 0.43 micron (count median aerodynamic diameter). The particle number and mass concentration increased as delta 9-THC concentration increased, being, respectively, 2.2- and 3.8-fold higher in the marijuana cigarette leaf with highest delta 9-THC concentration compared to the placebo marijuana cigarette. These data indicate the need for quantitative comparisons of other potentially toxic constituents in marijuana cigarettes of different delta 9-THC concentrations.

Cannabis↗
PubMed1979

The structure of A segments from glycerinated skeletal muscle.

The A band of skeletal muscle consists of an array of thick myosin-containing filaments along with non-myosin proteins such as C protein and M line protein. In order to study the arrangement of the myosin and non-myosin components, A segments which are aggregations of thick filaments held together at the M line were prepared from glycerinated chicken pectoral and rabbit psoas muscles and examined by electron microscopy. Details of the preparative technique and comparison of the morphologies of A segments and I segments are provided. The A segments from chicken pectoral muscle exhibited 11 to 12 stripes in each half lateral to the bare zone. Several less distinct bands as well as subdivisions of the individual stripes were also observed. The periodicity of the major stripes in the A segments was 424 +/- 10 A. The A segments prepared from rabbit psoas muscle had a periodicity of 432 +/- 13 A, but in contrast with chicken A segments, fewer rabbit A segments showed this periodicity. We conclude that A segments can be separated from glycerinated chicken and rabbit skeletal muscles and compare our results with those of others who prepared A segments from frog and rabbit skeletal muscles in the absence of glycerol.

Animals↗
PubMed1979

Method for sampling airway gas.

We have devised an improved technique for sampling gas from endotracheal airways for mass spectrometer analysis. It is reliable and unobtrusive and is particularly resistant to occlusion of the sampling line by secrections. It has performed well during continuous monitoring of patients in a respiratory ICU.

Gases↗
PubMed1978

Immunohistochemical and ultrastructural distribution of antibodies to troponin-C and troponin-I in normal and dystrophic chicken skeletal muscle.

The pectoral muscles from normal and dystrophic chickens were reacted with rabbit antisera to troponin-C and to troponin-I, and the distribution of antibodies was determined by fluorescence microscopy of antibody-stained myofibrils and immuno-electron microscopy of separated I band segments. Chickens of dystrophic strain 308 and control New Hampshire hens were used in this work. Myofibrils which were prepared from both normal and dystrophic muscles and reacted with anti-troponin-I were fluorescent in the I band and A band regions. The Z lines and H zones were unstained. Myofibrils prepared from normal pectoral muscle and treated with anti-troponin-C yielded a pattern of fluorescence similar to that for anti-troponin-I treated myofibrils. However, those myofibrils isolated from dystrophic muscle and reacted with anti-tropinin-C had a weak fluorescence over their entire lengths, and discrete A- and I-band staining was not visible. These results were confirmed by ultrastructural studies of separated I segments reacted with the antisera. It is concluded that in the dystrophic muscle either the antigenic sites of troponin-C are changed which results in a loss of antibody-combining ability or these sites are masked in some way which prevents the reaction with the antibody.

Animals↗
PubMed1977

An effect of avian hereditary muscular dystrophy on the reaction of troponin-C with its antibody.

Antibody prepared against troponin-C, the calcium binding component of the troponin complex, was reacted with I band segments, and the distribution of antibody binding was assessed by immuno-electron microscopy. The I segments were isolated from glycerinated pectoral muscle which was prepared from normal adult chickens and from dystrophic chickens of strain 308. The antibody was deposited at 384 A +/- 7 A intervals along the thin filaments of the normal muscle. In contrast to the normal controls the dystrophic muscle did not exhibit a distinct periodicity when reacted with anti-troponin-C. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed that although protein bands corresponding to troponin-C could be observed in the gels of the dystrophic preparations, the troponin-C band had migrated slower than that from normal thin filaments. It is concluded that avian muscular dystrophy produces an alteration of the structure of troponin-C resulting in (1) an inability of the protein to combine with its specific antibody and (2) a change in its electrophoretic behavior.

Animals↗
PubMed1977

Distribution of antibodies to the troponin complex, troponin-C and troponin-I in chicken skeletal muscle as determined by a simplified method for immuno-electron microscopy.

Antisera against the troponin complex, troponin-C and troponin-I have been utilized to locate these proteins in normal, adult chicken skeletal muscle and in filaments prepared from chicken acetone dried powder. The antisera had been previously characterized by immunochemical methods and were employed to ascertain the distribution of the proteins by a simple method for immuno-electron microscopy. Glycerinated chicken breast muscle was treated with the antisera, unreacted antibody was washed from the muscle, and a goat anti-rabbit gamma-globulin was added to enhance the electron density of the antigen-antibody complexes. A periodic distribution of anti-troponin-C at a mean interval of 389 A was observed along the thin filaments in the sectioned tissue. Anti-troponin-I was deposited every 399 A (P less than 0-01). Thin filaments were prepared from acetone dried powder and reacted with the antisera. The anti-troponin-C was located every 389 A; anti-troponin-I, every 399 A (P less than 0-01). Our technique for immuno-electron microscopy is compared with that used by others, and the significance of the findings is discussed.

Analysis of Variance↗