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Biomedical subjects

D L Fisher

Publications and source records attributed to D L Fisher.

At least 19 recordsLinked to original sources
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↗
PubMed1978

Modern operative fluorocholangiography: utopia or overlooked entity?

A system of image amplification with television fluoroscopy and 100 X 100 mm cut film technique is presented for use in the operating room. Biliary surgery has benefited from this equipment as operative cholangiography has been improved and unnecessary extension of operating time avoided. Applications of the equipment for other procedures are discussed.

Biliary Tract Surgical Procedures↗
PubMed1975

Effect of gonadotropins on ovulation and ovarian histology in the immature Mongolian gerbil.

The present study is an analysis of the effects of superovulatory doses of gonadotropins on the rate and time of ovulation and ovarian histology in immature gerbils. Groups were treated with various combinations of pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG). The maximum superovulatory response followed treatment with 10 IU PMSG and 20 IU HCG. High dosages of PMSG inhibited superovulation, as did some combinations involving the highest dose of HCG. Entrapment of ova within corpora lutes was common in groups receiving high doses of either gonadotropin. Luteal regression, appearing by day 3, occurred often in groups receiving high doses of HCG. A dose of 10 IU PMSG and 5 IU HCG resulted in both a near maximal superovulatory response and the least abnormal ovarian alteration.

Animals↗
PubMed1975

Direct selective myocardial revascularization by internal mammary artery-coronary vein anastomosis.

In this report, we shall describe our work with retrograde coronary perfusion, first in mongrel dogs and then in 6 patients. The left internal mammary artery (LIMA) is anastomosed to the left anterior descending coronary vein (LADV) to provide myocardial perfusion. This procedure may be of great value in the treatment of patients who are not suitable candidates for direct coronary bypass grafting, i.e., those who have diffuse atherosclerosis, with poor or no runoff of the left anterior descending coronary artery (LADA),but who have satisfactory left ventricular contraction.

Adult↗
PubMed1975

Reversal of pulmonary circulation.

The preliminary results and the technique of total reversal of the pulmonary circulation (RPC) are presented. Total RPC is technically feasible and not incompatible with life. It affords a new experimental model for in vivo study of pulmonary pathophysiology. The influence of this reversal on blood oxygenation, on pulmonary vascular resistance, and on established pulmonary hypertension, as well as its reaction to hypoxia and acidosis, needs further investigation. RPC may have clinical implications in essential pulmonary hypertension and congenital pulmonary vascular anomalies.

Angiography↗