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Biomedical subjects

M J Wilson

Publications and source records attributed to M J Wilson.

At least 73 records · Page 4Linked to original sources

Neonatal hypothyroidism alters the pattern of prostatic growth and differentiation, as well as plasminogen activator and metalloprotease expression, in the rat.

The purpose of this study was to examine whether changes in growth, ductal histology, and expression of plasminogen activator (PA) and matrix metalloproteases are associated with the increased prostatic weight and DNA content seen in adult rats that were treated neonatally with the goitrogen 6-propyl-2-thiouracil (PTU). Ventral prostatic weights were initially reduced in PTU-treated rats but were increased 40% over those of controls by Day 180; this increase in prostatic weight was also accompanied by increases in the number of prostatic ductal tips. In controls, prostatic PA and gelatinase A activities decreased after completion of morphogenesis at 21-28 days of age. In contrast to controls, PA and gelatinase A activities were maintained through puberty (42 days) in PTU-treated rats but declined by 90 days. The elevated PA activity in both prostatic lobes at 42 days of age in PTU-treated rats was inhibited by amiloride, indicating that it is the urokinase form of PA. These data show that the increased prostatic weight and DNA content in adult rats following neonatal PTU treatment results from a delayed but extended period of growth and the formation of new ductal elements. There is a temporal overexpression of urokinase and gelatinase A associated with the increased ductal branching, indicating as well an extended period of morphogenesis that results in their eventual increased adult size. The prostatic enlargement in PTU-treated rats may serve as a useful model to study regulation of both normal and abnormal prostatic growth and morphogenesis.

Amiloride↗

Genomic organization of a human killer cell inhibitory receptor gene.

We have cloned a region of human chromosome 19q13.4 which contains multiple killer cell inhibitory receptor (KIR) loci. By random and directed sequence analysis of these KIR-specific clones, we deduced the genomic structure of KIR genes. A locus encoding a member of the NKAT-2 family of KIRs is presented here. The structure of the gene is reminiscent of loci of the Fc receptor gene family, and the two sets of genes may derive from a common ancestor. The KIR gene contains potentially nine exons. The first two exons encode the leader sequence, as in Fc receptor genes. The third exon encodes an untranslated pseudo exon specifying an immunoglobulin domain with an in-frame stop codon. Expressed cDNAs do not contain this exon. This finding is consistent with the hypothesis that certain KIR genes may have been derived from the duplication of a primordial three immunoglobulin domain structure with subsequent skipping of one exon to derive genes with two expressed immunoglobulin domains. Variation in numbers of immunoglobulin domains in different KIR genes is facilitated by conservation of splicing frame in respect to the codon triplet for each immunoglobulin domain.

Alternative Splicing↗

Characterisation of the inflammatory cell infiltrate in chronic hyperplastic candidosis of the oral mucosa.

The inflammatory cell infiltrate in biopsy material of chronic hyperplastic candidosis (CHC) from the oral mucosa was characterised using immunocytochemical techniques. Nine specimens were stained for human kappa and lambda immunoglobulin light chains, CD68 antigen (macrophages), lysozyme (macrophages, granulocytes), CD3 antigen (T-lymphocytes), CD20 antigen (B-lymphocytes) and leucocyte common antigen (LCA). In addition, these and a further 13 specimens were also examined for immunoglobulin (Ig)-containing cells (IgA, IgG and IgM). The density of the infiltrate varied considerably between cases; T-lymphocytes were the dominant cell type (53.9%), with fewer B-lymphocytes (8.2%) and macrophages (14.2%). Many Ig-containing cells were seen, and although IgG-containing cells predominated, (60.8%, SD +/- 9.0) there was a high proportion of IgA-containing cells (36.7%, SD +/- 9.1) with few IgM-containing cells (2.5%, SD +/- 3.0). Many neutrophils, together with smaller numbers of T-lymphocytes and macrophages, were seen in the epithelium. It is suggested that mucosal defence to Candida infection involves a cell-mediated reaction in which there is recruitment of macrophages and local production of immunoglobulin with a prominent IgA component.

Adult↗

Glutamine- and phosphate-containing hypotonic storage media better maintain erythrocyte membrane physical properties.

We have shown that red blood cell (RBC) adenosine-5'-triphosphate (ATP) is better maintained and that there is less hemolysis and K+ leakage in hypotonic experimental additive solutions (EASs) containing glutamine and glutamine plus phosphate (Pi) than in the conventional additive solution Adsol during blood bank storage. The objective of this study was to determine if the beneficial effect produced in these media correlates with better preservation of RBC membrane properties including lipid content, phospholipid organization, aminophospholipid transport (flippase), and prothrombin converting activity. Aliquots of packed RBCs were stored in EASs containing adenine, glucose, sodium chloride, and mannitol, with 10 mmol/L glutamine (EAS 44) or with 10 mmol/L glutamine and 20 mmol/L Pi(EAS 45), or in Adsol. RBC membranes were studied after 0, 28, 42, and 84 days of storage, and vesicle membranes were studied after 84 days. RBC cholesterol and phospholipid content remained significantly greater (P < .01) in EASs than in Adsol. The degree of membrane vesiculation was more than 50% lower in EASs than in Adsol (P < .01). After 42 days of storage, the accessibility of phosphatidylethanolamine to phospholipases was approximately 1.5 times greater for Adsol and EAS 44 samples than for EAS 45 samples (43.5% v 28%). The rates of phosphatidylserine transport were 43% to 70% lower for stored cells but were not dependent on storage media. The amounts of bands 3 and 4.1 in the microvesicle membranes were not statistically different in any of the preparations. These results suggest that storage of RBCs in glutamine and Pi-medium better maintains ATP, lipid content, and phospholipid asymmetry and results in decreased vesiculation.

Adenine↗

Effects of castration on plasminogen activator activities and plasminogen activator inhibitor type 1 in the rat ventral prostate.

The involution of the prostate gland after castration is an active process which requires the induction of new proteins. The plasminogen activator urokinase has been proposed to be a gene repressed by androgen which is activated upon castration and thus participating in the atrophy of the gland. However, urokinase is secreted by the ventral lobe of the rat prostate and this should be positively affected by androgens. The purpose of this study was to examine further the effects of castration upon plasminogen activator (PA) activities in the rat prostate and to determine possible explanations to this apparent dilemma. Castration of young sexually mature adult rats resulted in a substantial increase in PA activities at 4 days after castration in the ventral prostate, but then the activities returned to within the range of untreated animals with a longer duration of castration. Urokinase was the predominant molecular form of PA in the normal ventral prostate and it was the molecular form increased after castration; based upon its sensitivity to amiloride and its molecular size determined in zymograms. In contrast to the effect of castration, there was no increase in PA activities in the ventral prostate with treatment of rats with the antiandrogen flutamide, but rather a decrease when specific activity was expressed per unit DNA. In addition, the effect of castration was specific for the ventral lobe for there was no change in the PA activity in the dorsolateral prostate after androgen ablation. The diminished PA activities in the ventral prostates of rats castrated for 7 days or longer appeared to be due at least in part to an increase in plasminogen activator inhibitor type-1 (PAI-1). Immunoreactive PAI-1 was found predominantly in high molecular weight forms which indicates that the inhibitor was complexed with PA. Daily treatment of rats upon castration with agents known to retard the rate of regression of the involuting prostate gave dichotomous results. Hydrocortisone prevented the increase in PA activity, whereas treatment with actinomycin D, an inhibitor of RNA synthesis, not only did not prevent an increase in PA activity, but actually produced a superinduction in PA activity at 4 days orchiectomy. These data may be interpreted to mean that hydrocortisone stimulated PAI activity and that actinomycin D treatment blocked its induction. However, the actinomycin D data may also indicate that an increase in urokinase protein and mRNA after castration may result from some mechanism to conserve these molecules suggesting that this inhibitor of RNA synthesis prevented the transcription of messages for proteins involved in the degradation of urokinase message.

Amiloride↗

Antibody immunoglobulin G (IgG) against human prostatic specific antigen (PSA) as a carrier protein for chemotherapeutic drugs to human prostate tumors: Part 1. A double immunofluorescence analysis.

BACKGROUND: Adenocarcinoma of the prostate (CaP) is the the second highest cause of cancer deaths in U.S. males. Current chemotherapeutic and/or endocrine treatments do not specifically and selectively target tumor cells of prostate cancer and benign prostatic hyperplasia (BPH). We hypothesized that because of the specific binding characteristics of antibody immunoglobulin G (IgG) to human prostatic-specific antigen (PSA), PSA-IgG could function as a carrier protein for conjugated chemotherapeutic drugs and that the immunoconjugate would selectively bind to prostatic epithelial cells and their tumors, but not to epithelial cells of unrelated organs. Our objective was to test the hypothesis using human prostatectomy specimens. METHODS: WE used several derivatives of 5'-fluorouracil, namely, 5'-fluoro- 2'-deoxyuridine (5'-Fu-2'-d), 5'-fluoro-2'-deoxyuridine-5' monophosphate (5'-Fu-2'-d-5'-mp), 5'-fluoro-2'-deoxyuridine-5'-(p-aminophenyl) monophosphate (5'-Fu-2'-d'-5'-amp), to conjugate with rabbit anti-PSA-IgG together with fluorescent markers (such as rhodamine and fluorescein or fluorescein isothiocyanate: FITC). Prostate specimens were obtained from prostatectomy patients who had not been treated with cytotoxic drugs before surgery. We evaluated formalin-fixed and paraffin-embedded sections as well as cryostat sections of frozen specimens for localization of PSA-IgG alone and PSA-IgG-drug immunoconjugate using immunoperoxidase (IP) and single and/or double immunofluorescence (IF) localization techniques. RESULTS: Our study showed that the immunoconjugate (PSA-IgG-5'-Fu-2'-d) bound to PSA (molecular size of approximately 34 KDa) on nitrocellulose sheets in Western immunoblots of extracts of BPH and CaP tissues. This binding of immunoconjugate to PSA on immunoblots was similar to that of the unconjugated PSA-IgG. Immunostaining patterns for rabbit anti-PSA-IgG and PSA-IgG-5'-Fu-2'-d immunoconjugate were similar and specific for prostate epithelial cells and their tumors, as revealed by IP techniques. To demonstrate that both the antibody and drug localized in the same group of prostatic epithelial cells, we used an immunoconjugate in which the PSA-IgG was labeled with rhodamine and 5'-Fu-2'-d-5'-amp with FITC. Our study showed that fluorescence for rhodamine and FITC was present in the same group of prostatic epithelial cells. Phase contrast microscopy demonstrated details of prostatic glandular epithelium and connective tissues. Our study showed that fluorescence for rhodamine and FITC and immunostaining by IP techniques were not observed in prostate sections incubated with normal rabbit serum. CONCLUSIONS: We have shown that conjugation of 5'-Fu derivatives to PSA-IgG did not affect either the selectivity or specificity of the antibody for prostatic epithelial cells. Differential immunofluorescence study has shown that PSA-IgG may function as a carrier protein for chemotherapeutic drugs to prostate epithelial cells and their tumors. Furthermore, FITC-labeled 5'-Fu-2'-d did not specifically localize in prostatic glands, kidney, lungs, bladder, or colon. Because of the specificity and selectivity of the immunoconjugate for prostatic epithelial cells and their tumors, the immunoconjugate could be used in small dosages to treat prostatic tumors and such treatment would greatly reduce many unpleasant side effects in patients. This is the first report to show that PSA-IgG can function as an organ specific carrier protein for chemotherapeutic drugs to human prostate epithelium and its tumors.

Antibodies↗

Chemical and mineralogical forms of Cu and Ni in contaminated soils from the Sudbury mining and smelting region, Canada.

Available information on soil contamination by trace elements in the Sudbury Cu/Ni mining and smelting region consists largely of total elemental concentration data. Little is known about the mode of occurrence and behaviour of Cu and Ni (the main metallic contaminants) in the soils of the region. In this study, sequential extraction and Scanning Electron Microscopy and Energy Dispersive X-ray Analysis (SEM/EDX) observations were complementarily used to define Cu and Ni forms in the Sudbury soils, so as to assess metal mobility. Most Cu (on average 75%) was associated with 'non-residual' soil forms, whereas Ni was mainly (on average 60%) associated with inorganic 'residual' forms of a sulphide and oxide nature. Therefore, Cu occurs in the soils in more mobile forms than Ni. Consequently, Cu should be removed from these soils at a faster rate than Ni. This is an unusual finding, because generally Ni is known to be more mobile in soils than Cu. SEM/EDX analysis confirmed the greater Cu mobility by showing that the metal was strongly associated with organic matter and was homogeneously distributed on the clay fraction surfaces. Nickel occurred alone or was associated with Fe oxides in various size fractions. Both elements were found as sulphides but Ni was often included in the silicate matrices of spherical particles in associations with Fe. SEM/EDX observations have shown that Cu and Ni are associated with soil forms which would not have been predicted by the sequential extraction alone, such as carbonaceous material, silicate spheres and carbonate particles, supporting complementary use of the two techniques.

Journal Article↗

A comparison of t test, F test, and coherence methods of detecting steady-state auditory-evoked potentials, distortion-product otoacoustic emissions, or other sinusoids.

Sinusoids in background noise can conveniently be detected using unsegmented power spectra, comparing power at the signal frequency to average power at several neighbor frequencies. In this case, the F test is preferable to t tests based on rms or dB values, because of the skewed distributions of rms and dB when signal-to-noise ratio (SNR) = 0. F-test performance improves as the number of frequencies increases, to about 15, but can be degraded if the background noise is not white, with a slope exceeding about 10 dB for the range of frequencies sampled. Segment analysis, using magnitude-squared coherence (MSC) or related statistics, has equivalent statistical power; MSC and F each yield unbiased SNR estimates that have identical distributions when SNR = 0. Selection of F or MSC for detection of sinusoids will usually be a matter of convenience.

Evoked Potentials, Auditory↗

Identification of Candida species in formalin fixed, paraffin wax embedded oral mucosa by sequencing of ribosomal DNA.

Aim-To identify Candida species in formalin fixed, paraffin wax embedded tissue by sequencing candidal rDNA.Methods-Target rDNA sequences were amplified by polymerase chain reaction (PCR) from fresh isolates of Candida and from 18 preserved oral mucosal tissue samples (16 cases of chronic hyperplastic candidiasis and two fibroepithelial polyps), shown histologically to contain Candida. Identification of Candida species within tissue was based on a comparison of the rDNA sequences obtained with those from the fresh isolates of Candida and those present in the GenBank database.Results-The PCR products obtained from 12 of the 18 tissue specimens studied were characteristic of Candida albicans. In two of these cases a second, larger PCR product was obtained and these sequences were characteristic of Candida glabrata.Conclusions-Candidal DNA was amplified successfully from formalin fixed, paraffin wax embedded tissue. Sequencing of the PCR product enabled identification of the Candida species present.

Journal Article↗

Cathepsin B in angiogenesis of human prostate: an immunohistochemical and immunoelectron microscopic analysis.

BACKGROUND: Angiogenesis (or neovascularization) is required for the growth of solid organ tumors and precedes invasion of the adjacent stroma by neoplastic cells. We investigated the relative density and distribution of cathepsin B (CB) immunostained microvessels (i.e., small blood vessels and capillaries) in benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), and prostatic adenocarcinoma (CAP) by immunocytochemical localization of an antibody directed against a cathepsin B-derived synthetic peptide (Syn-CB). METHODS: We studied 16 formalin-fixed, prostatectomy specimens that were embedded in paraffin/paraplast for histological examination by hematoxylin and eosin and immuno-localization of the Syn-CB antibody. Selected paraformaldehyde-fixed specimens were embedded in K4M Lowicryl or LRWhite resins. We localized the antibody in thin sections using immunoelectron microscopy techniques. RESULTS: Eight patients had BPH [4 patients with BPH alone, 2 with BPH and PIN, and 2 with BPH and CAP]. Ten cancer cases included one with Gleason histologic score 4, two with score 6, four with score 7, and three with score 8. In CAP cases, Gleason score 6 and 7 tumors had more microvessels than the score 4 or 8 tumors. In both BPH and CAP cases, the antibody was localized chiefly in the endothelial cells of microvessels, but occasionally in ductal and glandular epithelial cells. Ultrastructurally, CB-immunoreactive gold particles were markedly increased at the luminal and basal plasma membrane surfaces and folds of endothelial cells in neoplastic prostate, but not in the endothelial cells of BPH. Furthermore, the presence of CB localizing gold particles in collagen and smooth muscle fibers near the microvessels indicated leakage of the enzyme in prostatic stroma of neoplastic prostate. Similar leakage was not observed in BPH. Morphometric analysis showed that the relative density of microvessels increased two to three times in cancer patients when compared to patients with BPH alone. Our study also indicated that BPH associated with PIN or CAP had an increased density of microvessels when compared to BPH alone. CONCLUSIONS: Our study showed that the relative density and distribution of microvessels are the most important features of neovascularization in prostatic tumors. The relative density of microvessels increased in PIN and CAP when compared to BPH alone. Although the localization of CB is associated with lysosomes of endothelial cells in both BPH and CAP, there is a greater association of CB with the plasma membranes of endothelial cells in CAP than BPH. Immunoelectron microscopy provided evidence that CB might be involved in dissolution of basement membranes in neoplastic tumors during angiogenesis. CB localization has the potential of defining a role for this protease in degradation of extracellular matrix constituents during early steps of angiogenesis.

Adenocarcinoma↗

Immunohistochemical localization of cathepsin B in neoplastic human prostate.

Cathepsin B (CB) has been shown to degrade extracellular matrix (ECM) proteins, and has been reported to be involved in invasion and metastasis of several types of solid organ tumors in human and animals, but CB has not been studied in human prostate cancer (CAP). Our objective was to determine the CB protein immunostaining pattern in CAP and to correlate the immunostaining with the degree of malignancy as reflected in the Gleason grading system. We used two types of CB antibodies (namely, monospecific, polyclonal antibodies to human liver CB prepared in rabbits, and polyclonal antibody produced in sheep) to establish CB localization patterns in neoplastic prostate. Our analysis showed a heterogeneous CB immunostaining pattern in the neoplastic human prostate. CB immunostaining occurred in many, but not all, of the neoplastic columnar/cuboidal cells of acini and isolated cells, i.e., in small ragged glands and clusters (groups) of invasive cells in the prostatic stroma. We have shown that, in general, there was a positive correlation of the intensity of CB immunostaining with the Gleason histologic score (or Gleason grade sum) tumors, i.e., from the lowest scores through score 8, but many of the tumors with scores 9 and 10 showed little CB immunostaining. Our study indicated that the increased CB immunostaining in the Gleason grade sum 5-8 tumors may be associated with increased degradation of ECM, but not in 9 and 10 despite the fact that the latter tumors are more malignant clinically. In well-differentiated tumors, fewer CB immunostaining cells were present than the moderately-differentiated tumors. In other words, most of the stromal invasion of the prostatic ECM occurred in tumors of Gleason grade sums 5-8. We suggest that CB immunostaining might be a useful method to assess stromal invasion of prostatic carcinoma, especially in the higher grade tumors.

Animals↗

The sensitivity of surface waters of Great Britain to acidification predicted from catchment characteristics.

Using a combination of soil, land use and geological information, a map of Great Britain has been derived which indicates the sensitivity of surface waters to acidification. For the geological information, a slightly modified version of an available map was used which indicated the sensitivity of groundwaters to acidification. For soils, 1-km databases of soil information for England and Wales and for Scotland were employed to map the soil sensitivity as determined by buffering capacity. The derived soils map was modified to take account of agricultural liming in arable and managed grassland areas using the ITE Land Classification. The final map of surface water sensitivity was obtained by using a geographic information system overlay procedure which enabled each combination of soil and geology sensitivity to be uniquely defined. The final sensitivity classification was based upon expert knowledge and the experience of a similar sensitivity mapping exercise for Wales.

Journal Article↗

Comparison of objective threshold estimation procedures for 40-Hz auditory evoked potentials.

OBJECTIVE: Objective threshold estimation is possible using statistics such as magnitude-squared coherence (MSC) and responses such as the 40-Hz auditory evoked potential (AEP). The purpose of this paper is to compare three general methods of threshold estimation using MSC. DESIGN: Using 500-Hz amplitude-modulated tones and 40-Hz AEPs from 10 paid-volunteer young adults with normal hearing, we compared three MSC-based threshold estimation methods--extrapolation, intensity series, and adaptive. RESULTS: The extrapolation method yielded low thresholds but unacceptable variability. The intensity series method was insensitive and time-consuming. Two adaptive methods displayed good performance in terms of precision and sensitivity. The first employed an MSC criterion with a 13.5% false positive rate (per trial), but achieved overall false positive rates under 5% after 5 to 7 runs, requiring 30 to 40 minutes test time (a run is a single set of ascending or descending trials, terminated by a reversal). The second, which performed better overall, included only a single run, but collected more data at intensities near threshold than at higher intensities; test time could be further reduced (from 22 to 18 minutes) by using a stopping rule based on initial MSC and noise power estimates at each test intensity. If speed is paramount, a simple single-run method achieved threshold estimates in about 9 minutes, starting at 40 dB nHL, with acceptable precision but less sensitivity. CONCLUSIONS: A single-run adaptive method, with or without collection of additional data near threshold, yielded the best results, in terms of statistical performance and data collection time.

Adult↗

Restriction fragment length polymorphism analysis of PCR-amplified 16S ribosomal DNA of human Capnocytophaga.

The confusion in the taxonomic status of the genus Capnocytophaga has made identification of strains and studies on the role of this genus in infectious diseases equivocal. In this study 33 strains of Capnocytophaga including reference strains and various clinical isolates, were studied using RFLP analysis of 16S ribosomal RNA genes. The 16S ribosomal RNA (rRNA) gene sequences from whole cell suspensions and isolated genomic DNA samples were amplified by the polymerase chain reaction (PCR) using eubacterial specific primers. PCR products were purified and characterized by single digestions with 12 restriction endonucleases. Five of these, BanI, CfoI, HaeIII, HphI and RsaII were found to discriminate reproducibly between strains, and restriction patterns (ribotypes) produced by these were analysed to clarify the classification of Capnocytophaga strains. Dendrograms inferring similarities were derived from these data by the UPGMA method. This analysis produced three major clusters of strains, each of which was associated with a previously proposed species type strain: C. gingivalis, C. sputigena and C. ochracea. The results support the division of Capnocytophaga into three species and demonstrate that, despite the heterogeneity of this genus, the modified ribotyping method provides a simple, rapid and reproducible way to identify Capnocytophaga strains.

Bacterial Typing Techniques↗

Objective versus human observer detection of 40-Hz auditory-evoked potentials.

Magnitude-squared coherence (MSC) was used to detect 40-Hz auditory-evoked potentials (AEPs) in a two-alternative forced-choice experiment. MSC performance was found to be better than that of ten human observers. Experienced observers did not perform better than naive observers. In a "yes-no" experiment, observers demonstrated large differences in criterion, with false-positive rates of 2%-20%. Observers also performed better when AEPs were presented in a 50-ms window (two response cycles) than when presented in a 205-ms window (eight response cycles), although total test time was the same; MSC performed equally well in both cases. MSC provides a useful and objective adjunct to visual detection of 40-Hz AEPs.

Adult↗

Molecular and biochemical characterization of a protective 40-kilodalton antigen from Corynebacterium pseudotuberculosis.

A 40-kDa protein from Corynebacterium pseudotuberculosis has been previously identified as a protective antigen against ovine caseous lymphadenitis. From genomic DNA libraries of C. pseudotuberculosis, we have cloned and sequenced the 40-kDa protein gene, which was found to contain an open reading frame of 1,137 bp encoding a protein of 379 amino acids. No significant homology with previously published DNA or amino acid sequence data was found in databases, suggesting that this is a novel protein. Recombinant 40-kDa protein was overexpressed as a fusion protein to 15% of total cell proteins in Escherichia coli. Biochemical analysis of native and recombinant 40-kDa proteins has revealed associated proteolytic activity, which was shown to be of the serine protease type through the use of specific inhibitors. We suggest that this novel protective antigen be termed corynebacterial protease 40 (CP40).

Amino Acid Sequence↗

Identification of Candida species by PCR and restriction fragment length polymorphism analysis of intergenic spacer regions of ribosomal DNA.

The PCR was used to amplify a targeted region of the ribosomal DNA from 84 Candida isolates. Unique product sizes were obtained for Candida guilliermondii, Candida (Torulopsis) glabrata, and Candida pseudotropicalis. Isolates of Candida albicans, Candida tropicalis, Candida stellatoidea, Candida parapsilosis, and Candida krusei could be identified following restriction digestion of the PCR products.

Base Sequence↗