Biomedical subjects
M R Wilson
Publications and source records attributed to M R Wilson.
Sequential multiplex amplification: utility in forensic casework with minimal amounts of DNA and partially degraded samples.
Since its introduction, PCR has become a widely-used, routine technique in forensic laboratories. A number of PCR protocols that were developed originally are now being replaced by more powerful approaches, particularly those based on multiplex amplification of short tandem repeat (STR) loci. One alternative from of multiplex PCR amplification, called Sequential Multiplex Amplification (SMA), was designed to amplify a single locus and then recover and reuse the remaining genomic DNA as a template for subsequent PCR. The SMA process could be repeated several times. SMA has proven to be useful in typing genomic DNA contained in stored PCR samples and analyzing samples of limited quality and/or quantity for multiple loci. The efficacy of the use of SMA for actual typing of casework samples permitted typing for a second locus 98.11% of the samples considered; 70.75% were typeable for a third locus, and 16.98% for a fourth locus.
A population-based study of xerophthalmia in the extreme North Province of Cameroon, West Africa.
OBJECTIVE: To obtain cross-sectional data on clinical and nutritional vitamin A deficiency from which to design appropriate intervention strategies. DESIGN: A population-based survey using multistage, cluster sampling. SETTING: Extreme North Province of Cameroon, West Africa. PARTICIPANTS: Children aged 0 to 5 years. MAIN OUTCOME MEASURES: Clinical signs of active xerophthalmia and dietary vitamin A intake. RESULTS: Of 5352 children examined, signs of active xerophthalmia were noted in 0.62%. Bitot's spots, corneal xerosis, and corneal ulceration were noted in 0.47%, 0.06%, and 0.12% of the subjects, respectively. Children with xerophthalmia had lower vitamin A intake scores when compared with age-matched controls and with a 20% systematic subsample of children. CONCLUSION: Xerophthalmia is a major public health problem in this region.
Efficacy of ofloxacin vs cefazolin and tobramycin in the therapy for bacterial keratitis.
Explore the source record for details and available documents.
Identification and characterization of a heat shock protein 70 family member in channel catfish (Ictalurus punctatus).
We have determined the cDNA sequence of a member of the channel catfish heat shock protein 70 (CF Hsp70) family. This protein presumably functions as a molecular chaperone, as is characteristic of this family in other species. Channel catfish peripheral blood leukocytes exhibit a classical heat shock response, in that heat shock (37 degrees C) induces the expression of heat shock genes that are quiescent at normal temperatures (23 degrees C). It was observed that pre-existing synthesis of certain other molecules was suppressed (as evidenced by decreases in actin RNA upon heat shock). Similar trends were observed in mRNA expression for CF Hsp70 in two catfish non-leukocyte cell lines, channel catfish ovary and F59. However, three leukocyte cell lines constitutively expressed high levels of CF Hsp70 mRNA at optimal culture temperature (27 degrees C), whereas heat shock (37 degrees C) elicited only a modest induction of CF Hsp70 expression. Furthermore, continued investigation is warranted to determine whether the apparent upregulation of CF Hsp70 mRNA expression in the catfish long-term leukocyte cell lines is involved in the seemingly immortal phenotype of these cells.
Demographic factors in a population-based survey of hospitalized, work-related, ocular injury.
PURPOSE: To obtain population-based estimates of the incidence of severe work-related ocular trauma and to identify demographic factors related to increased risk of this type of injury. METHODS: A statewide population-based survey of severe work-related ocular injury was performed using hospital discharge data. These data were derived from all inpatient admissions to nonfederal, acute-care hospital facilities in the state of California during 1988. Worker's compensation was used as the principal payor code to establish the work-relatedness of a given ocular injury. Census data for the state of California were used to obtain population denominators. RESULTS: Two hundred sixty-nine (approximately 14.3%) of all admissions for which ocular trauma was the principal diagnosis (1,876) were work related. Annual incidence for severe work-related ocular injury was 1.76 per 100,000 employed persons when ocular trauma was the principal diagnosis and 2.98 per 100,000 employed persons when ocular trauma was a principal or secondary diagnosis. Projected to the working-age United States population (128 million) these annual rates correspond to an estimated 2,165 acute hospitalizations for work-related ocular trauma as the principal diagnosis, and an estimated 3,745 acute hospitalizations for work-related ocular trauma as a principal or secondary diagnosis. Incidence of severe work-related ocular injury was highest among men, Hispanics, and individuals 20 to 24 years of age (5.02, 3.72, and 4.64 per 100,000 employed per year, respectively). CONCLUSIONS: The workplace accounts for a substantial proportion of severe ocular injury. Demographic groups at highest risk for this type of injury are men, Hispanics, and young adults.
Melorheostosis of the skeletally immature hand: a case report and long-term follow-up evaluation.
Explore the source record for details and available documents.
Epithelial cell-derived transforming growth factor-beta in bleomycin-induced pulmonary injury.
We have investigated whether enhanced secretion of transforming growth factor-beta (TGF-beta) by distal respiratory epithelial cells was associated with the development of bleomycin-induced pulmonary fibrosis. Type 2 pneumocyte-enriched preparations of bronchioloalveolar epithelial cells from normal mouse lung tissue released latent TGF-beta when cultured in serum-free medium. TGF-beta in culture supernatants could be detected using a sensitive enzyme immunoassay which employed enzyme complex amplification as a reporter system, as well as by a radiolabelled receptor competition assay. Exposure to bleomycin and other potentially fibrogenic stimuli in vitro did not stimulate production of TGF-beta by the epithelial cells but release was enhanced by treatment of the cells with interferon-gamma. Type 2 pneumocyte-enriched cell preparations obtained following induction of a pulmonary inflammatory response by administration of intratracheal bleomycin to susceptible C57BL/6 mice did not demonstrate increased release of TGF-beta in culture. However, the concentration of TGF-beta in bronchoalveolar lavage (BAL) fluids was significantly elevated compared to controls at 1 and 2 weeks after bleomycin-induced injury in these mice. No such increase was detected in BAL fluids from BALB/c mice, which are resistant to the effects of bleomycin. These results provide no support for a pathogenetic role of alveolar epithelial cell-derived TGF-beta in bleomycin-induced pulmonary fibrosis. Nevertheless, elevated levels of TGF-beta in BAL fluids may provide a marker of the progression of pulmonary injury to fibrosis.
Clusterin, a putative complement regulator, binds to the cell surface of Staphylococcus aureus clinical isolates.
The ability of Staphylococcus aureus Cowan I strain and a number of S. aureus clinical isolates to bind to the human blood glycoprotein clusterin was investigated. Binding of clusterin to these strains was tested by both enzyme-linked immunosorbent assay and flow cytometry. All of the S. aureus strains examined appeared to bind clusterin to some extent, while nonpathogenic control strains Bacillus subtilis BR151 and Escherichia coli JM109 did not. Three S. aureus isolates were selected for more detailed study; binding of labeled clusterin was saturable, inhibited in the presence of excess unlabeled clusterin, and prevented by pretreatment of bacteria with proteases. From the saturation binding studies, estimates of the affinity constants for the binding of clusterin to the bacteria ranged from 31 to 57 nM. Addition of clusterin to S. aureus cultures was also found to result in aggregation of the bacterial cells; aggregation was not detected when clusterin was added to B. subtilis BR151 or E. coli JM109 cultures. These results suggest that at least some S. aureus strains possess specific proteinaceous receptors for clusterin. Such receptors may be an important new bacterial virulence determinant for S. aureus, as clusterin has been proposed to have a role in the regulation of complement activity.
Inhibition of gap junctional intercellular communication in normal human breast epithelial cells after treatment with pesticides, PCBs, and PBBs, alone or in mixtures.
Chemical pollutants in the Great Lakes have found their way through the food chain into humans because of their environmental persistence and lipophilicity. Some epidemiological studies have claimed an association between metabolites of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT), polychlorinated biphenyls (PCBs), and polybrominated biphenyls (PBBs) and breast cancer, but others have reported no such association. We examined various halogenated hydrocarbons for their capacity to inhibit gap junctional intercellular communication (GJIC) in normal human breast epithelial cells (HBEC) when given as single compounds or as mixtures. The scrape-loading/dye transfer and fluorescent redistribution after photobleaching techniques were used to measure GJIC; immunostaining and Western and Northern analyses were performed on connexin 43 (Cx43) gap junction protein and message to determine how halogenated hydrocarbons might affect GJIC. DDT, dieldrin, and toxaphene inhibited GJIC in a dose-responsive manner after 90 min treatments. Dieldrin suppressed GJIC within 30 min with no recovery after 24 hr. Inhibition of GJIC by DDT and toxaphene was partially restored after 12 hr and fully restored after 24 hr. Several PCB and PBB congeners inhibited GJIC in a dose-responsive and time-dependent manner, but GJIC was almost restored to control values 24 hr after exposure. The highest concentrations of the individual chemicals that did not inhibit GJIC was determined, and mixtures containing two of these chemicals were tested for their ability to inhibit GJIC. Significant inhibition of GJIC was observed when cells were treated with a mixture of DDT and 2,4,5-hexachlorobiphenyl (2,4,5-HCB), dieldrin and 2,4,5-HCB, or dieldrin and 2,4,5-hexabromobiphenyl (2,4,5-HBB). These results indicate that halogenated hydrocarbons, alone or in specific combinations, can alter GJIC at the post-translational level. These results are consistent with the hypothesis that DDT, dieldrin, toxaphene, 2,3,4-HCB, 2,4,5-HCB, and 2,4,5-HBB could have tumor-promoting potential in human breast tissue.
Prevalence and causes of low vision and blindness in the Extreme North Province of Cameroon, West Africa.
A survey to determine the prevalence and causes of blindness and visual impairment in the Extreme North Province of Cameroon was conducted in the Spring of 1992. A total of 10,647 people age 6 years and older was selected from a multi-stage, clustered sample stratified by ecological zone. The subjects were examined by ophthalmologist-led teams for visual acuity and ocular diseases. Approximately 1.2% of the sample was bilaterally blind by the World Health Organization classification (Category 3) of vision less than the ability to count fingers at 3 meters. Similarly to results found in other developing countries, senile cataract was the most common diagnosis encountered and the most frequent principal cause of low vision and blindness.
Translating research into practice: controlled clinical trials and their influence on glaucoma management.
Historically, management strategies for glaucoma have stressed reduction of IOP as the primary goal. Yet, if we question this principle, we find a deficiency of information to support it as the optimal strategy for managing glaucoma patients and those at risk of developing glaucoma. Thus, the practice of lowering IOP in glaucoma management was placed on trial by the 1987 Eddy and Billings report (D. M. Eddy and J. Billings, 1987). Although generally denounced by clinicians, this report nonetheless alerted the ophthalmologic community that success of glaucoma treatment must be measured by endpoints unrelated to IOP and that a controlled trial to demonstrate glaucoma treatment efficacy was necessary. A clinical trial is an experiment. As such, it is the best study design for inferring causality between an exposure (e.g., IOP) and an outcome (e.g., glaucoma), and it is the best methodology for demonstrating treatment efficacy. However, it is important to understand that efficacy is not the same as effectiveness. Whereas "efficacy" is the extent to which a specific intervention produces a beneficial result under ideal conditions, "effectiveness" is the extent to which a specific intervention, when deployed in the field, does what it is intended to do. The influence of study results on the practice of medicine is more a function of demonstrated effectiveness than efficacy of an intervention. All of the completed glaucoma clinica trials reviewed were well performed, and many have had a substantial influence on the philosophy and practice of glaucoma management. The glaucoma clinical trials currently being performed represent the highest standards of clinical trial methodology. This is an exciting time for clinical research on glaucoma. Well accepted dogmas are being challenged, and the ophthalmic community is aggressively addressing difficult issues. Questions being asked are of fundamental importance and addressing them is essential. Particularly exciting in these trials is the fact that IOP is not being considered as an endpoint and that consideration is being given to the previously ignored but extremely important issue of overall patient well-being. Only with time will the ultimate impact of these trials on the philosophy and practice of glaucoma management become evident.
Progressive upregulation of metastasis-related genes in human colon cancer cells implanted into the cecum of nude mice.
We determined whether the upregulation of several metastasis-related genes in human colon carcinoma (HCC) cells implanted into the cecal wall of nude mice precedes HCC invasion of the muscle layer and subserosa and, ultimately, distant metastasis. HCC KM12SM cells were implanted into the subcutis (ectopic) or cecal wall (orthotopic). At weekly intervals for up to 6 weeks, cecectomy and resection of SC tumors were performed on different groups of mice. Survival and metastasis were assessed at 13 weeks. During the first 2 weeks after orthotopic implantation, the HCC cells grew progressively in the mucosa and submucosal layers of the cecum. By the third week, the cells invaded the muscularis propria and then the serosa. All mice undergoing cecectomy at weeks 1 and 2 were cured, whereas those undergoing cecectomy at later weeks were not. In situ hybridization analysis for expression of several metastasis-related genes-epidermal growth factor receptor (EGF-R), basic fibroblast growth factor (bFGF), collagenase type IV, and E-cadherin-revealed that the expression level of EGF-R, bFGF, and collagenase type IV in the early cecal tumors was low but increased just before invasion of the muscularis propria. At all times, the level of gene expression in the cecal tumors was higher than in the SC tumors. In contrast, the expression level of E-cadherin remained constant and did not differ between tumors in ectopic or orthotopic organs. The data suggest that the upregulation of some metastasis-related genes precedes tumor cell invasion and production of metastasis.
Dexfenfluramine as an adjunct to a reduced-fat, ad libitum diet: effects on body composition, nutrient intake and cardiovascular risk factors.
OBJECTIVE: To investigate the specific effects of dexfenfluramine (dF) as an adjunct to a reduced-fat, ad libitum diet. DESIGN: Double-blind, randomized, placebo-controlled study. Subjects were stabilized on the dietary program during a 12 w run-in period, and then were randomized to receive dF (15 mg) or placebo bd for an additional 12 w. One follow-up was conducted 12 w after cessation of treatment. SUBJECTS: 84 obese subjects (57 F; 27 M, mean body mass index = 34.7 +/- 3.2 kg/m2). MEASUREMENTS: Body composition (by DEXA), fat distribution (by circumferences and DEXA), nutrient intake (by 7 d food diaries), blood lipids, blood glucose and blood pressure. RESULTS: Mild side effects were reported by 19 dF subjects, and in seven subjects lethargy or dry mouth persisted for the 12 w of treatment. Relative to placebo, treatment with dF was associated with significantly greater reductions in body weight (-3.8 kg, 95% confidence interval [CI] = -4.9, -2.7), fat mass (-2.5 kg, 95% CI = -3.6, -1.4) and fat-free mass (-1.2 kg, 95% CI = 1.8, -0.7). Waist and hip circumferences also decreased (P < 0.01) but the waist:hip ratio remained unchanged. The ratio of waist:hip fat mass as measured by DEXA decreased more in the dF group (P < 0.01). Lower total energy intake (-439 kJ/d, 95% CI = -932, 54) and fat intake (-5.1 g/d, 95% CI = -10.8, 0.6) were also seen but were of borderline statistical significance. After adjusting for changes in fat intake, dF treatment was associated with lower cholesterol and triglyceride concentrations (P < 0.01). Twelve weeks following cessation of treatment, the rate of weight gain was not significantly different between the dF and the placebo groups (1.7 kg and 0.7 kg respectively), but the dF group remained significantly lighter than the placebo group (P < 0.01). CONCLUSIONS: Dexfenfluramine treatment augments weight and fat loss on a reduced-fat, ad libitum diet, with some evidence for preferential loss of waist fat compared with hip fat. The decreases in total energy and fat intake with dF seem insufficient to explain the significant decreases in body weight and fat mass.
Evaluation of zona pellucida antigens as potential candidates for immunocontraception.
Antibodies directed against the zona pellucida can interrupt sperm-egg recognition in vitro. However, the mechanisms by which anti-zona antibodies exert this contraceptive effect in vivo remain uncertain. There is an accumulating body of evidence to suggest that active immunity against zona antigens not only induces infertility via an antibody-mediated interruption of sperm--egg interaction but also disrupts normal ovarian function. We have evaluated the consequence of inducing active immunity against purified recombinant human ZP3 (rec.hZP3) and human ZP3 peptides, using the marmoset monkey, Callithrix jacchus, as an animal model. Although infertility was established in animals that received rec.hZP3, it was associated with ovarian dysfunction characterized by suppression of folliculogenesis and depletion of the primordial follicle pool. Immunization with continuous human ZP3 peptides, identified by epitope mapping studies, did not induce ovarian pathology but the antibody titres were insufficient to suppress fertility significantly and consistently. Clearly, further research is required to identify and segregate epitopes on the zona glycoproteins that are capable of inducing infertility without any side effects.
Selection of highly metastatic variants of different human prostatic carcinomas using orthotopic implantation in nude mice.
The purpose of this study was to determine whether the implantation of human prostate cancer cells into the prostates of nude mice and their subsequent growth there can be used to select variants with increasing metastatic potential. PC-3M and LNCaP cells were injected into the prostates of athymic mice. Tumors from the prostate or lymph nodes were harvested, and cells were reinjected into the prostate. This cycle was repeated three to five times to yield cell lines PC-3M-Pro4, PC-3M-LN4, LNCaP-Pro3-5, and LNCaP-LN3-4. Parental and variant cells were injected into the prostates of nude mice. PC-3M-LN4 cells produced enhanced regional lymph node and distant organ metastasis as compared to PC-3M-Pro4 or PC-3M cells. After i.v. or intracardiac inoculation, PC-3M-LN4 cells produced a higher incidence of lung metastasis and bone metastasis, respectively, than PC-3M or PC-3M-Pro4 cells. Subsequent to implantation into the prostate, LNCaP-LN3 cells produced a higher incidence of regional lymph node metastases than LNCaP-Pro5 or LNCaP cells. After intrasplenic implantation, LNCaP-LN3 cells also yielded experimental liver metastases. The metastatic LNCaP-LN3 cells exhibited clonal karyotypic abnormalities, were less sensitive to androgen (in vitro and in vivo), and produced high levels of prostate-specific antigen. Collectively, the data show that the orthotopic implantation of human prostate cancer cell lines in nude mice is a relevant model with which to study the biology of prostate cancer metastasis and to select variant cell lines with enhanced metastatic potential.
Validation of mitochondrial DNA sequencing for forensic casework analysis.
Two sets of studies were performed to evaluate the forensic utility of sequencing human mitochondrial DNA (mtDNA) derived from various tissues and amplified by the polymerase chain reaction (PCR). Sequencing was performed on a Perkin-Elmer/Applied Biosystems Division (PE/ABD) automated DNA sequencer (model 373A). The first set of experiments included typical validation studies that had previously been conducted on forensic DNA markers, such as: chemical contaminant effects on DNA from blood and semen and the effect of typing DNA extracted from body fluid samples deposited on various substrates. A second set of experiments was performed strictly on human hair shafts. These studies included typing mtDNA from hairs that were: (1) from different body areas, (2) chemically treated, (3) from deceased individuals, and (4) deliberately contaminated with various body fluids. The data confirm that PCR-based mtDNA typing by direct automated sequencing is a valid and reliable means of forensic identification.
Initial clinical experience with the Ahmed glaucoma valve implant--correction.
Explore the source record for details and available documents.