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Biomedical subjects

J L Fox

Publications and source records attributed to J L Fox.

At least 289 records · Page 16Linked to original sources
PubMed1983

Quantitation of cutaneous Langerhans cells of sarcoidosis patients.

Langerhans cells play a role in cell-mediated immune reactions which are often depressed in sarcoidosis. We examined the epidermis of 17 anergic patients with sarcoidosis (Kveim-reactive and/or biopsy-proved) for the number of Langerhans cells in noninvolved skin and in any cutaneous sarcoidal lesions. Skin biopsies of 10 healthy volunteers served as controls. In comparison to controls, the epidermis overlying noninvolved (p less than 0.05), sarcoidal (p less than 0.0005), and Kveim-reactive (p less than 0.005) skin contained significantly fewer detectable Ia and T6 antigen-bearing Langerhans cells. The reductions within noninvolved skin were most pronounced in patients with multisystem disease. Lower epidermal Langerhans cell densities, in comparison to controls, were detected in both prednisone-treated and untreated patients. Epidermis overlying sarcoidal skin of untreated patients contained significantly fewer Ia and T6 antigen-bearing Langerhans cells (p less than 0.05, p less than 0.0025, respectively) than epidermis from noninvolved skin. Whether reduced numbers of cutaneous Langerhans cells are due to either a local and/or systemic effect of sarcoidosis, or reflect the anergic state of these patients is unknown.

Adult↗
PubMed1983

Skin metastases from small-cell carcinoma of the lung.

This paper reports the first case of skin metastases from small-cell carcinoma of the lung with electron microscopic confirmation. The 2 to 3-cm cutaneous lesions present on the chest and limbs were hard, nontender, smooth-surfaced, freely moveable nodules with normal appearing overlying skin. Characteristic dense-core granules 1562 +/- 123 A (SEM) in diameter were detected by electron microscopy. The detection by electron microscopy of dense-core granules may assist in confirming the diagnosis of small-cell carcinoma in cutaneous lesions with equivocal histologic findings.

Aged↗
PubMed1982

Histidine decarboxylase of Lactobacillus 30a. Comparative sequences of the beta chain from wild type and mutant enzymes.

Manual and automated sequencing of peptides isolated from tryptic, chymotryptic, and Staphylococcus aureus V8 protease digests of the beta chain of histidine decarboxylase from Lactobacillus 30a have established the following sequence for the wild type protein: NH2-Ser-Gly-Leu-Asp-Ala-Lys-Leu-Asn-Lys-Leu-Gly-Val-Asp-Arg-Ile-Ala-Ile-Ser-Pro -Tyr-Lys-Gln-Trp-Thr-Arg-Gly-Tyr-Met-Glu-Pro-Gly-Asn-Ile-Gly-Asn-Gly-Tyr-Val-Thr-Gly-Leu-Lys-Val-Asp-Ala-Gly-Val-Arg-Asp-Lys-Ser-Asp-Asp-Asp-Val-Leu-Asp-Gly-I le-Val-Ser-Tyr-Asp-Arg-Ala-Glu-Thr-Lys-Asn-Ala-Tyr-Ile-Gly-Gln-Ile-Asn-Met-Thr- Thr-Ala-Ser-COOH The beta chain from mutant 3 of this organism shows two amino acid replacements: Ser-51 is replaced by Ala and Gly-58 by Asp. These amino acid replacements result in a significant increase in the predicted alpha-helical content and a significant decrease in the isoelectric point of the mutant beta chain and are consistent with changes in physical and catalytic properties of the mutant histidine decarboxylase. In addition, about 15% of the mutant chains contain Met-Ser at the NH2 terminus rather than Ser. Asn-35 is partially deamidated in both proteins. Structural comparisons show that the histidine decarboxylase from Lactobacillus 30a and a similar pyruvoyl enzyme from Micrococcus sp. n. have evolved from a common ancestral protein.

Amino Acid Sequence↗
PubMed1982

Familial intracranial aneurysms. Case report.

A case with two intracranial aneurysms is presented. The situation is unique because the patient was one of 13 siblings, seven of whom are now known to have harbored such aneurysms. The patient, now deceased from rupture of her aneurysm, was one of the two siblings who had previously refused elective angiography.

Cerebral Angiography↗
PubMed1982

Evaluation of computer-assisted self-instructional module for pharmacy continuing education.

A computer-assisted self-instructional module was developed as a method of providing continuing education to pharmacists. A prospective, nonrandomized study was conducted to investigate the effectiveness of computer-assisted instruction (CAI). Using an Apple II microcomputer and anticoagulant therapy as the content base, a series of ten case studies was written and programmed. Twenty-two staff pharmacists from a university hospital and a community hospital participated. Participants were first given a pretest, proceeded through the CAI, took the same test as a posttest, then two weeks later, took a different posttest to measure knowledge retention. The mean test scores before and immediately after the CAI were 55.8% and 80.4%. The mean test score for the two-week posttest was 74%. The mean difference was found to be highly significant for both the pretest and immediate posttest (P less than 0.0001) and the pretest and two-week posttest (P less than 0.001). The study suggested that the use of a CAI module was effective in improving, as well as maintaining, pharmacists' knowledge and that a significant portion of knowledge gained was retained after a period of two weeks. Pharmacists' evaluations of this method of continuing education were generally favorable.

Computer-Assisted Instruction↗
PubMed1981

Fluoride remineralization of demineralized bovine tooth enamel and hydroxyapatite pellets.

Both bovine enamel and hydroxyapatite pellets were remineralized in a fluoride-containing remineralization solution after prior demineralization for various lengths of time. In both the enamel and pellet systems, the degree of remineralization attainable was directly related to the extent of prior demineralization, although the demineralized material was never 100% recovered in remineralization. In some cases, fluoride levels up to several thousand parts per million were found at depths as great as 50 micrometers from the surface. The stoichiometry of the remineralized material and electron microprobe examination were consistent with the formation of fluoridated hydroxyapatite rather than calcium fluoride.

Animals↗
PubMed1981

Novel topical fluoride delivery system I: remineralization of ground bovine teeth.

Laboratory studies were carried out on a newly conceived fluoride-containing remineralizing system with bovine teeth. The prototype fluoride delivery device involved micronized calcium fluoride maintained at the tooth surface with a cellulose film. Together with salivary calcium and phosphate (or simulated saliva), this system was able to generate and maintain the appropriate thermodynamic activity driving force for significant fluorapatite deposition in a reasonably short time (approximately 48 hr).

Animals↗
PubMed1981

Novel topical fluoride delivery system II: remineralization of human teeth.

A recently conceived calcium fluoride-containing remineralization system was tested using human teeth in vitro. The influence of several variables (surface pretreatment, demineralization time, and remineralization time) was studied. Appreciable levels of fluoride taken up by pumiced human teeth were found at depths up to 50 micrometers when remineralization was carried out in either the remineralizing solution or saliva. The successful performance of the delivery device in these laboratory studies is encouraging and indicates that the logical evolution of the crude devices studied thus far could lead to clinically practical fluoride delivery devices.

Fluorides↗
PubMed1981

Responses of the anterior pituitary of ovariectomized rats to oestradiol-17 beta administration.

The response of the female rat anterior pituitary gland to oestradiol-17 beta administered sc by silastic capsule implants (6-120 microgram/day) has been examined. Cholesterol, oestradiol-17 alpha, and testosterone were used as control hormone implants. The biochemical changes in the gland as assayed by DNA, RNA, and protein contents were monitored at intervals of 7, 21, 42, and 120 days. In addition, the number of cells per gland was determined by an experimental cell counting technique and correlated to the number of cells based on total DNA content. These results extend previous observations of the hypertrophy of the anterior pituitary and show essentially parallel increases in cell number, DNA, RNA, and protein contents.

Animals↗
PubMed1981

The role of manipulation following total knee replacement.

During a twelve-month period, 23 per cent of a series of knees undergoing total replacement were manipulated two weeks postoperatively to increase flexion. While manipulation achieved an immediate increase in flexion from a mean of 71 degrees to a mean of 108 degree, by one week after manipulation the mean flexion was reduced to 88 degrees. By one year postoperatively, the manipulated knees were found to have a range of motion similar to that of their non-manipulated counterparts. Such factors as preoperative flexion and diagnosis appear to be the major determinants of ultimate flexion, and they seem to offset the temporarily increased flexion afforded by manipulation. The primary reason for manipulation is to facilitate the postoperative rehabilitation program for patients with painful, limited motion of the knee.

Arthritis, Rheumatoid↗
PubMed1980

Purification and characterization of the C-phycocyanin from Agmenellum quadruplicatum.

The C-phycocyanin from the marine blue-green alga, Agmenellum quadruplicatum, has been isolated and purified to electrophoretic homogeneity. This is the first C-phycocyanin for which a low resolution three dimensional structure has been published (Hackert, M.L., Abad-Zapatero, C., Stevens, S.E. Jr. and Fox, J.L. (1977), J. Mol. Biol. 111, 365-369 and Abad-Zapatero, C., Fox, J.L. and Hackert, M.L. (1977) Biochem. Biophys. Res Commun. 78, 266-272). The native C-phycocyanin complex shows an absorption maximum at 622 nm and another peak at 355 nm. In urea solutions, the 622 nm maximum of whole C-phycocyanin is shifted to 662 nm. Am662 = 94400 was determined. The fluorescence emission maxima at 650 nm for haloprotein is shifted and largely quenched in acid urea. The monomeric protein consists of two polypeptide chains with molecular weights of 16,000 for the alpha chain and 18,500 for the beta chain. Spectra in 8 M urea indicate that the alpha chain possesses one and the beta chain two phycocyanobilin chromophores. The isolated chains show absorption maxima at 622 nm for the alpha chain and 608 nm for the beta chain. Amino acid compositions of the holoprotein and the separated chains are given and N-terminal amino acid sequences are presented.

Amino Acid Sequence↗
PubMed1980

Physical model evaluation of topical prodrug delivery--simultaneous transport and bioconversion of vidarabine-5'-valerate III: Permeability differences of vidarabine and n-pentanol in components of hairless mouse skin.

The permeation behavior of 3H-vidarabine (3H-9-beta-D-ara-binofuranosyladenine) and 14C-n-pentanol through different strata of hairless mouse skin was studied using a diffusion cell at 37 degrees under steady-state conditions. Partition coefficients for the skin components verus 0.9% aqueous NaCl solution also were obtained. Various skin preparations including full-thickness skin, cellophane-stripped skin, and dermis membranes of different thicknesses were employed. The dermis membranes were considered to be diffusionally homogenous, and the product of the permeability coefficient and the thickness was taken as the apparent diffusivity. The apparent diffusivities for both compounds investigated were independent of thickness. Therefore, it was concluded that the molecular diffusivity is constant throughout the dermis. Comparisons of permeability coefficients in various strata of the skin revealed that, while the stratum corneum is the major diffusional barrier, the epidermis appears to be significantly less permeable than the dermis.

Administration, Topical↗
PubMed1980

Physical model evaluation of topical prodrug delivery--simultaneous transport and bioconversion of vidarabine-5'-valerate IV: Distribution of esterase and deaminase enzymes in hairless mouse skin.

A semiquantitative assessment of estrase and deaminase distributions in hairless mouse skin was performed in vitro. The enzyme activities were quantified using 3H-vidarabine and tis 5'-valerate as the substrates. Full-thickness skin of the hairless mouse was cut into two halves, and each half was homogenized in pH 7.4 buffer. BQOTH THE SUPERNATE AND THE RESIDUE OF THE HOMOGENATE were assayed for esterase and deaminase activities. Results show that the outer half-thickness of the skin contained more esterase but slightly less deaminase than the other half. The characteristics of the esterase and the deaminase reactions also were studied employing the crude enzyme extract; these reactions were essentially irreversible. The deaminase reaction was in the linear region of Michaelis-Menten kinetics for substrate concentrations up to 4.5 x 10(-5) M.

Aminohydrolases↗
PubMed1980

Physical model evaluation of topical prodrug delivery--simultaneous transport and bioconversion of vidarabine-5'-valerate V: Mechanistic analysis of influence of nonhomogeneous enzyme distributions in hairless mouse skin.

The mathematical problem of simultaneous transport and metabolism in the case of nonuniform enzyme distributions in the skin was solved, and the solutions were used for analyzing experimental data. Experimental data were obtained from permeation experiments with 3H-vidarabine and its 5'-valerate using cellophane tape-stripped hairless mouse skin. Results of the analyses revealed that the esterase activity was four to nine times higher in the epidermis than in the dermis, whereas the deaminase activity was about the same in the two strata. These results were in good agreement with independent experiments using tissue homogenates. The enzyme distributions and the previously reported diffusivities were employed in generating concentration profiles for the prodrug and the drug in the skin. These results may be used in predicting the possible therapeutic effect of the prodrug when it is topically applied.

Administration, Topical↗