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Biomedical subjects

D L Fisher

Publications and source records attributed to D L Fisher.

At least 37 records · Page 2Linked to original sources
PubMed1993

Short tandem repeat loci: application to forensic and human remains identification.

The short tandem repeat (STR) locus ACTBP2 (common name SE33) was analyzed for its potential use in forensic and human remains identification. PCR amplification conditions were determined, and an allele-specific ladder was generated so that discrete alleles could be scored. The allele frequency distributions were determined for both Caucasian and Black populations. The frequency data meets Hardy-Weinberg expectations, and the allele distributions were similar from one racial group to another and between ethnic groups. SE33 analysis was subsequently used to confirm the identification of human remains for the Office of the Armed Forces Medical Examiners.

Alleles↗
PubMed1993

Repetitive motion disorders: the design of optimal rate-rest profiles.

Repetitive motion disorders of the upper extremities are the primary cause of lost time in hand-intensive industries. Typical remedies include the introduction of job aids and the redesign of the job. An alternative approach is considered here. Procedures are developed that can be used to determine the parameters of a job (e.g., the rate of work and the number and duration of the rest breaks) that minimize repetitive motion disorders and maximize productivity. It is shown that in theory the job parameters can be set so that one can achieve not only a decrease in repetitive motion disorders but also an increase in productivity. The application of the procedures to an actual manufacturing job requiring high-repetitive, high-force hand motions is discussed in detail.

Cumulative Trauma Disorders↗
PubMed1993

A systematic approach to the sampling of dental DNA.

As investigations into the forensic aspects of DNA analysis continue, the human tooth will play a dual role in identification. Dentin and enamel provide a protective enclosure for genomic and mitochondrial DNA as well as providing the basis for radiographic, biochemical, and ultrastructural forensic studies. The purpose of this investigation is to establish technical guidelines, based on histology and experimental evidence, for the management and sampling of dental DNA. The anatomic location of dental DNA is discussed with emphasis on the conservation of tooth structure during sampling. Ten pairs of maxillary right and left third molars were sampled for DNA following storage for 18 weeks at ambient temperature and humidity. Right third molars were crushed, whereas the left third molars were sectioned conservatively prior to sampling the DNA. The quantity and quality of human DNA obtained from each tooth was compared, as well as the radiographic appearance of remaining hard tissue and the overall simplicity of each approach. DNA typing was performed, both sequence and length based analyses, comparing teeth from the same individual and teeth from different donors. The results of this study suggest that the odontologist will maximize the dental DNA yield by crushing the entire specimen but that substantial yields of human DNA can be obtained by using a conservative technique that preserves the tooth structure. In addition, the method of sampling does not affect the ability to perform DNA typing analyses.

Adolescent↗
PubMed1993

Extraction, evaluation, and amplification of DNA from decalcified and undecalcified United States Civil War bone.

Deoxyribonucleic acid (DNA) was extracted from documented skeletal specimens of U.S. Civil War soldiers to determine the need for decalcification prior to extraction. The polymerase chain reaction (PCR) was performed to determine if the calcification state had an effect on the ability to amplify the extracts and to determine how successful amplification would be with these aged specimens. Bone samples were pulverized to a fine powder and divided into two sets. One set of samples was decalcified and the other set left undecalcified. Both sets were extracted using an organic procedure. The results demonstrate that decalcification is not a necessary step in the extraction process and that the yield of DNA is generally two times greater when decalcification is omitted. Furthermore, the calcification state had no effect on the ability to perform the PCR. Although the extracted DNA was very degraded, a 410 base pair (bp) segment of the mitochondrial DNA (mtDNA) control region was amplified. These results suggest that DNA can be extracted and amplified from 125 year old bone without decalcification, which may assist in the identity of modern and historic forensic specimens.

Anthropology, Physical↗
PubMed1993

Mitochondrial DNA sequence analysis of human skeletal remains: identification of remains from the Vietnam War.

Deoxyribonucleic acid (DNA) sequence analysis of the control region of the mitochondrial DNA (mtDNA) genome was used to identify human skeletal remains returned to the United States government by the Vietnamese government in 1984. The postmortem interval was thought to be 24 years at the time of testing, and the remains presumed to be an American service member. DNA typing methods using nuclear genomic DNA, HLA-DQ alpha and the variable number of tandem repeat (VNTR) locus D1S80, were unsuccessful using the polymerase chain reaction (PCR). Amplification of a portion of the mtDNA control region was performed, and the resulting PCR product subjected to DNA sequence analysis. The DNA sequence generated from the skeletal remains was identical to the maternal reference sequence, as well as the sequence generated from two siblings (sisters). The sequence was unique when compared to more than 650 DNA sequences found both in the literature and provided by personal communications. The individual sequence polymorphisms were present in only 23 of the more than 1300 nucleotide positions analyzed. These results support the observation that in cases where conventional DNA typing is unavailable, mtDNA sequencing can be used for human remains identification.

Anthropology, Physical↗
PubMed1992

Sexual abuse of children. The detection of semen on skin.

OBJECTIVE: The detection of semen on the skin of children who present within 72 hours of an episode of sexual assault is critical to medical, forensic, and legal personnel. The Wood's Lamp, a UV light that causes semen to fluoresce, and four forensic laboratory techniques were compared to determine their sensitivity and decline in sensitivity over time. DESIGN: A descriptive study. PARTICIPANTS: Eleven adult female volunteers. MEASUREMENTS/MAIN RESULTS: Semen was placed on the skin of the volunteers. Samples of the dried semen were assessed during a 28-hour period with the Wood's Lamp, microscopy, the acid phosphatase assay, and two assays for the prostatic protein p30 (counterimmunoelectrophoresis and enzyme-linked immunosorbent assay). The intensity of the Wood's Lamp fluorescence of semen diminished dramatically by 28 hours; in contrast, the fluorescence of urine persisted up to 80 hours. Over time, the p30-enzyme-linked immunosorbent assay technique was more sensitive than microscopy, the acid phosphatase assay, and p30-counterimmunoelectrophoresis in detecting semen on skin. CONCLUSIONS: The Wood's Lamp is not a sensitive screening tool and should be used with caution. To improve the detection of sexual abuse in children, we recommend that the p30-enzyme-linked immunosorbent assay be used because of its potential as a more sensitive assay than those in current clinical use.

Acid Phosphatase↗
PubMed1992

General slowing alone cannot explain age-related search effects: reply to Cerella (1991)

Cerella (1991) has argued that the performance of older adults in the Fisk and Rogers (1991) study is a linear function of the performance of younger adults that is independent of task-specific cognitive requirements. We demonstrate that this is not the case. First, we show that the scatter plot analyses used by Cerella can hide the very task-specific age-related slowing they were designed to reveal. Second, we demonstrate that the percentage of variance explained by such analyses can be misleading. Third, we show that there are reliable differences across tasks in the parameters relating younger and older adults' performance. Finally, we argue that the general, task-independent proportionate slowing that Cerella suggested explains so much of the variance in age-related performance is actually an average slowing that is a function of a relatively small task-independent and a relatively large task-dependent factor.

Adult↗
PubMed1991

Regulation of protein secretion by crinophagy in perfused rat liver.

We examined the secretion of three serum proteins, albumin (RSA), alpha 2 mu-globulin (alpha 2 mu G), and transferrin (Trf), in the isolated perfused liver. Within 4 h of perfusion, only 20 to 35% of previously synthesized proteins were secreted by the liver into the recirculating medium. Low temperature inhibited the secretion of alpha 2 mu G and Trf, but not RSA. The amount of RSA secreted by the liver increased twofold in the presence of leupeptin, a proteinase inhibitor, or primaquine, a weak base capable of neutralizing acidic compartments. Neither drug affected Trf secretion, while the release of alpha 2 mu G was enhanced threefold by primaquine treatment. Only 55 to 70% of the total amount of these serum proteins present in the liver at the onset of perfusion could be accounted for after 4 h of perfusion. Our evidence suggests that these losses are due to protein degradation. The degradation of RSA and alpha 2 mu G was inhibited at 15 degrees C and by both leupeptin and primaquine. Contrary, RSA degradation was not altered when livers were perfused at 20 degrees C. Morphological techniques combined with immunological probes were utilized to identify possible intracellular sites of RSA degradation. RSA and cathepsin L were colocalized to large vacuoles found near the cell periphery. Entry of RSA into these vacuoles occurred at 20 degrees C but not at 15 degrees C. Our results using perfused rat livers suggest that as much as 40% of hepatic serum proteins are degraded via fusion of secretory vesicles with lysosomes (e.g., crinophagy).

Alpha-Globulins↗
PubMed1990

Cloning and expression of a hybrid Streptomyces clavuligerus cefE gene in Penicillium chrysogenum.

A hybrid cefE gene was constructed by juxtaposing promoter sequences from the Penicillium chrysogenum pcbC gene to the open reading frame of the Streptomyces clavuligerus cefE gene. In S. clavuligerus the cefE gene codes for the enzyme penicillin N expandase [also known as deacetoxycephalosporin C synthetase (DAOCS)]. To insert the hybrid cefE gene into P. chrysogenum the vector pPS65 was constructed; pPS65 contains the hybrid cefE gene and the Aspergillus nidulans amdS gene. The amdS gene encodes acetamidase and provides for dominant selection in P. chrysogenum. Protoplasts of P. chrysogenum were transformed with pPS65 and selected for the ability to grow on acetamide medium. Extracts of cells cultivated in penicillin production medium were analyzed for penicillin N expandase activity. Penicillin N expandase activity was detected in approximately one-third of the transformants tested. Transformants WG9-69C-01 and WG9-61L-03 had the highest specific activities of penicillin N expandase: 4.3% and 10.3%, respectively, relative to the amount of penicillin N expandase in S. clavuligerus. Untransformed P. chrysogenum exhibited no penicillin N expandase activity. Analysis of the penicillin V titer revealed that WG9-61L-03 produced titers equal to that of the recipient strain while the amount of penicillin V produced in WG9-69C-01 was reduced by five fold.

Blotting, Southern↗
PubMed1989

Visual displays: the highlighting paradox.

Office computer users view well over a billion displays in a given year. The savings of only a fraction of a second in the time it takes users to process each display can potentially lead to enormous time and cost savings. In recent research investigators have shown that on average subjects are quicker to find a target option in a highlighted display than in a display without highlighting. Paradoxically, in related research other investigators have shown that subjects are slower to find a target in a highlighted display than in a display without highlighting. In an attempt to resolve this paradox, an additional set of experiments was performed. Results from these experiments suggest that in order to determine whether highlighting will be of benefit, one must know the type of highlighting, the level of highlighting validity, and the probability that subjects attend first to the highlighted options.

Adult↗
PubMed1989

Minimizing the time to search visual displays: the role of highlighting.

Office computer users frequently need to search long lists of options for a particular target. Highlighting a subset of the options can shorten the average display search time. The goal of the current research was to identify the subset of options to highlight that minimizes users' average search time for any given display. To begin, a mathematical model of the visual search process was constructed which could be used to predict the average search time for a target in a display with or without highlighted options. The predictions of this model were then compared with the results of a visual search experiment that varied the type of highlighting (blocked, random, or no highlighting), the number of highlighted options, and the probability that a target was highlighted. Overall the predictions of the model were consistent with the results from the experiment. Finally, procedures based on the model were developed which could be used to find the optimal subset of options to highlight for a given display--that is, the subset of highlighted options that minimizes users' search times.

Computers↗
PubMed1988

Understanding the central processing limit in consistent-mapping visual search tasks.

Effects of load (i.e., the number of stimuli in the display) have been observed in multiple-frame studies using a consistent mapping of stimuli to responses (e.g., Fisher, 1982, 1984). In a series of four experiments, it is shown that these effects are not the consequence of differences across the high- and low-load conditions in either decision noise or peripheral masking. Additionally, it is shown that of two modes of limited capacity (a limited-channel and divided-capacity model) considered as possible explanations of load effects in tasks where subjects are required to locate a target, only one--the limited-channel model--is consistent with the results from all three location tasks. Finally, it is argued that the limited-channel model predicts not only the behavior observed in the four consistent-mapping experiments reported in this article but also the behavior observed in several related consistent-mapping tasks (Kleiss & Lane, 1986; Shiffrin & Gardner, 1972).

Attention↗
PubMed1987

Efficient integrative transformation of Cephalosporium acremonium.

A hybrid gene, IPNSp/HPTorf, was constructed by placing an 850 bp sequence of Cephalosporium acremonium DNA next to the 5' end of a bacterial open reading frame, HPTorf. The sequence was obtained as an 850 bp NcoI restriction fragment from the 5' non-coding region of the C. acremonium isopenicillin N synthetase (IPNS) gene. The HPTorf was obtained from a bacterial gene that coded for a hygromycin B phosphotransferase (HPT). Plasmids that contained IPNSp/HPTorf transformed C. acremonium to a stably maintained hygromycin B resistant phenotype. Southern analysis of total DNA from transformants demonstrated multiple integrations of the transforming DNA in the high molecular weight DNA of most transformants, but single integrations were observed in a few transformants. The number of transformants per microgram of DNA was about 100 times greater than for plasmids that contained the HPTorf without any juxtaposed eucaryotic promoter sequence. Plasmids with the promoterless HPTorf and plasmids with a truncated S. cerevisiae phosphoglycerate kinase promoter juxtaposed to the HPTorf transformed C. acremonium at equivalent low frequencies. Transformation of C. acremonium with linearized plasmid DNA produced at least 2-3 fold more transformants than the corresponding circular molecule. Several observations were made concerning protoplast formation and handling which made the transformation procedure more efficient and allowed a greater proportion of protoplasts to regenerate to viable walled cells. Plasmids were constructed that contained both the IPNSp/HPTorf and additional elements: fragments of C. acremonium ribosomal DNA (rDNA), or a fragment of C. acremonium mitochondrial DNA possessing activity as an autonomous replication sequence (ARS) in S. cerevisiae, or putative transcriptional termination/polyadenylation signals from the IPNS gene. These plasmids transformed C. acremonium at frequencies experimentally equivalent to those containing IPNSp/HPTorf without any of these additional elements.

Acremonium↗
PubMed1983

Markov models and the utilization of mental health services: a study of endogenously depressed patients.

Patients in the mental health care system typically make more or less irregularly spaced visits to psychiatrists, both within and between episodes of a given illness. A Markov model is constructed which can predict the utilization of psychiatric services for such patients. Unlike previous Markov models of utilization, the current model takes as its starting point a model of an actual disease, specifically, endogenous depression. It is shown how one can estimate the parameters of both the model of utilization and the model of depression using data which were collected for clinical research purposes. The models provide reasonable fits to the data. Several applications of the models are worked out. In addition to predicting the utilization of mental health services, the models can be used to predict incidence, prevalence and recovery rates and to predict the changes in utilization which parallel changes in treatment regimens.

Depression↗
PubMed1982

Effects of hormones on postimplantation mouse embryos in vitro. II. Progesterone and estrogen.

Mouse embryos at day 9 of development were cultured for 24 to 42 h in 50% fetal calf serum and 50% Waymouth's medium containing 0.5 micrograms/ml insulin supplemented with various amounts of progesterone and estradiol-17-beta. Unmodified medium contained approximately 0.2% of the normal maternal blood levels for that stage of pregnancy. The addition of 1 X 10(-7)M progesterone to the medium brought the level near that of the normal maternal circulating amount and appeared to be beneficial for in vitro development. After 24 h of cultivation there was a statistically significant increase in somite number, the number of embryos developing posterior limb buds, and protein accumulation over the control embryos. The addition of small amounts of estradiol-17 beta (1 X 10(-10)M) increased the protein accumulation of the embryo over that of progesterone alone and seems to enhance the beneficial effects of progesterone addition.

Animals↗