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Biomedical subjects

A Cohen

Publications and source records attributed to A Cohen.

At least 451 records · Page 25Linked to original sources
PubMed1993

Orientation asymmetry in the flanker task.

Experiments 1 and 2 of this study show that when the target is either a vertical or a horizontal line, diagonal-line flankers tilted 45 degrees either to the right or to the left have the same effect as do incongruent flankers. When the target is a diagonal line tilted either to the right or to the left, vertical- or horizontal-line flankers do not have the same effect as do incongruent flankers. Experiment 3 demonstrates that this asymmetry is not caused by the temporal-dynamic aspects of the processing. Together, these experiments suggest that there is an asymmetrical relation between diagonal lines and either vertical or horizontal lines outside of the central focus of attention. Experiment 4 shows that despite this asymmetry in the flanker task, visual search for a vertical- or a horizontal-line target among diagonal-line distractors is not affected by the number of distractors. Possible explanations of this phenomenon are discussed.

Adult↗
PubMed1993

South African psychiatrists' criteria for predicting dangerousness.

The prediction of dangerousness has emerged as one of the most controversial issues in forensic psychiatry. It is a value-laden and ambiguous concept which has not been adequately defined and operationalized by the law or psychiatry. The validity and reliability of psychiatric predictions of dangerousness have been brought seriously into question in the past few decades. The Booysen Commission appointed in South Africa relates to the problem. An exploratory survey to ascertain the variables which South African psychiatrists perceive as influencing their decisions about dangerousness and to compare these findings with those of previous research was undertaken. One hundred and thirty-eight psychiatrists were included in a survey by means of a questionnaire. Findings that clinicians' decisions were significantly influenced by patients' criminal/violent history were consistent with previous research. The article further evaluates the responses to the questionnaire variables and the degree as well as a study of detained 'dangerous' patients to assess accuracy of evaluations in practice.

Attitude of Health Personnel↗
PubMed1993

[Incidental finding of an isolated thrombus in the left atrium in a young woman with sinus rhythm 5 years after cerebral ischemic accident].

The authors report the case of a 40 year old woman who had an ischemic stroke. The initial investigation including a complete blood clotting analysis, failed to demonstrate the cause. Five years later, the investigations were completed systematically by transesophageal echocardiography which demonstrated an isolated thrombus localised in the left atrial appendage though the localisation heart was in sinus rhythm and morphologically normal. This case illustrates in the diagnostic yield of transesophageal echocardiography in the investigation of systemic embolism in young patients who have had a cerebral ischemic event of unknown cause, even in the absence of predisposing cardiac cause.

Adult↗
PubMed1993

[Evaluation of alternative hemoculture tests for the diagnosis of early neonatal sepsis].

In order to evaluate the diagnostic usefulness of coadjuvant tests such as external auditory canal swab culture and cultures from nasopharyngeal and gastric aspirates, and to determine the incidence and etiology of early neonatal sepsis (ENS) at our Unit, 90 newborn cases whose mothers experienced premature rupture of the membranes (PRM) were studied prospectively. Although a firm diagnosis requires positive blood cultures, the difficulty in recovering microorganisms and the trauma induced by sample collection in the baby justify the search for alternative diagnostic tests. Out of 2293 childbirths during 1991, 90 mothers (4%) had PRM more than 24 hours pre-partum, while 6.9/1000 (16/2293) developed ENS. In newborns from PMR mothers, ENS percentage was 3.3%, but increased to 5.5% in association with chorionamnionitis and reached 8.8% in premature cases. Among etiological ENS agents, Gram-positive microorganisms predominated (Table 1), particularly Staphylococcus aureus. Despite the finding that none of the coadjuvant assays (Table 2) had sufficient sensitivity or positive predictive value to identify all septic cases, they may prove useful to pinpoint newborns at high risk due to amniotic fluid exposure to infection or to chorioamnionitis.

Argentina↗
PubMed1993

Dermatofibrosarcoma protuberans appearing during pregnancy.

Dermatofibrosarcoma protuberans is an uncommon skin tumor with a high potential for local recurrence if not adequately excised. There are only two reports in the literature describing dermatofibrosarcoma protuberans that enlarged considerably during pregnancy. On the other hand, the new development or enlargement of dermatofibromas in pregnancy is well documented. We present 2 additional patients in whom a dermatofibrosarcoma protuberans appeared and grew rapidly during pregnancy. Immunohistochemical studies were negative for estrogen and progesterone receptors. The possible pathophysiology and surgical management are presented and discussed.

Adult↗
PubMed1992

tDNA(ser) sequences are involved in the excision of Streptomyces griseus plasmid pSG1.

Plasmid pSG1 is maintained in some derivatives of Streptomyces griseus NRRL3851 mainly in the chromosomally integrated form (pSG1int). In others, the integrated plasmid is co-maintained with free pSG1 [Cohen et al., Plasmid 13 (1985) 41-50]. The pSG1 plasmid integration site (attP) and the pSG1int-chromosome boundaries (attL and attR) were cloned and sequenced. The results indicate that pSG1int is flanked at attL by a functional tRNA(ser) gene and at attR by a 60-nt sequence of the 3' end of the same tRNA(ser) gene. A single mismatch distinguishes the 60-nt sequence at attR from its direct repeat at attL. The attP site contains a single copy of the 60-nt repeat, identical to the one at attL. This observation indicates that pSG1, like integrating plasmids of other Actinomycetes, is integrated in a tRNA gene and suggests that the exact excision of pSG1int occurs by a recombinational crossing-over event at the first 43 nt of the 60-nt repeat.

Amino Acid Sequence↗
PubMed1992

Immunization of colorectal cancer patients with modified ovine submaxillary gland mucin and adjuvants induces IgM and IgG antibodies to sialylated Tn.

Tn and sialylated Tn (sTn) are blood group-related epitopes expressed on mucins of colon carcinoma and other epithelial tumors and are, therefore, potential targets for immunological control. We have immunized 20 colorectal cancer patients at high risk for recurrence with a vaccine consisting of partially desialylated ovine submaxillary gland mucin (modified OSM) which contains both Tn and sTn determinants. Six patients were treated with modified OSM alone (group 1), eight patients were treated with modified OSM and the immunological adjuvant DETOX (group 2), and six patients were treated with modified OSM and Bacillus Calmette-Guérin (group 3). Pre- and postvaccination sera were tested by enzyme-linked immunosorbent assay and dot blot immune stains for antibodies reactive with modified OSM. Antibody titers increased in 4 of 8 patients immunized with modified OSM and DETOX, in 5 of 6 patients immunized with modified OSM and B. Calmette-Guérin, and in 0 of 6 patients receiving modified OSM without adjuvant. The specificity of induced IgM and IgG antibodies was confirmed by demonstrating reactivity with OSM, bovine submaxillary mucin, and synthetic glycoconjugates sTn-human serum albumin (HSA) and Tn-HSA in enzyme-linked immunosorbent assay and immune stains. Median IgM pre-postvaccination reciprocal titers were 20/80 for Tn-HSA and 10/320 for sTn-HSA. Low level IgG antibody titers against sTn-HSA were detected after vaccination in 7 patients. Toxicity was limited to inflammatory skin reactions at the site of vaccination resulting from the adjuvants. No inflammatory infiltrates were seen in the skin when the modified OSM vaccine was administered in the absence of an immunological adjuvant. These results demonstrate that sTn and Tn can be recognized by the human immune system and that vaccines containing these structures can be administered safely with immunological adjuvants. Attempts to augment the immunogenicity of these carbohydrate antigens by covalent attachment to immunogenic carrier proteins and the use of more potent immunological adjuvants are now being pursued.

Adjuvants, Immunologic↗
PubMed1992

Identification of an interleukin 2-like substance as a factor cytotoxic to oligodendrocytes and associated with central nervous system regeneration.

Axons of the central nervous system in adult mammals do not regenerate spontaneously after injury, partly because of the presence of oligodendrocytes that inhibit axonal growth. This is not the case in lower vertebrates (e.g., in fish), where regeneration of the optic nerve does occur spontaneously and has been correlated with the presence of factors cytotoxic to oligodendrocytes. The present study provides evidence that the substance originating from the fish optic nerves, which is cytotoxic to oligodendrocytes, is an interleukin 2-like substance.

Animals↗
PubMed1992

Decreased platelet imipramine binding in Tourette syndrome children with obsessive-compulsive disorder.

[3H]Imipramine binding to blood platelets was assessed in eight untreated Tourette syndrome (TS) children, nine drug-free TS children with obsessive-compulsive disorder (OCD), and nine age-matched and gender-matched control subjects. The density of [3H]imipramine binding sites in TS + OCD patients was significantly lower compared with TS-OCD patients (28%) as well as when compared with controls (31%). This alteration was not accompanied by differences in the affinity of the binding site to the ligand. The decreased density of the platelet serotonin "transporter" might implicate the involvement of the serotonergic system in the pathophysiology of OCD in TS patients, but not in TS per se.

Adolescent↗
PubMed1992

Localizing genes on the map of the genome of Haloferax volcanii, one of the Archaea.

We have assigned genetic markers to locations on the physical map of the genome of the archaeon Haloferax volcanii, using both a physical method (hybridization) and a more specific genetic technique (transformation with cosmids). Hybridizations were against restriction digests of each of 151 cosmids making up a minimally overlapping set and covering 96% of the genome. Results with a cloned insertion sequence and a tRNA probe indicated that transposable elements are concentrated on two of the four plasmids of this species, whereas regions complementary to tRNA are largely chromosomal. For a genetic analysis of genes involved in the biosynthesis of amino acids, purines, and pyrimidines, we used cosmid transformation to assign 139 of 243 ethyl methanesulfonate-induced auxotrophic mutations, generated and characterized for this study, to single cosmids or pairs of cosmids from the minimal set. Mutations affecting the biosynthesis of uracil, adenine, guanine, and 14 amino acids have been mapped in this way. All mutations mapped to the 2920-kilobase-pair chromosome of Hf. volcanii and seemed uniformly distributed around this circular replicon. In some cases, many mutations affecting a single pathway map to the same or overlapping cosmids, as would be expected were genes for the pathway linked. For other biosynthetic pathways, several unlinked genetic loci can be identified.

Archaea↗
PubMed1992

[Treatment of onychomycosis using 40% urea with 1% bifonazole].

The rate of success in treating onychomycosis with 40% urea ointment containing 1% bifonazole, with and without oral griseofulvin, was evaluated. Most patients had onychomycosis of the toes. 11 patients (group A: 5 men and 6 women, average age 48.5) were treated locally under occlusion with the ointment until dissolution of most of the nail, and then with 1% bifonazole cream for a total of 6 months. 11 others (group B: 3 men and 8 women, average age 42.5) received, in addition, griseofulvin 500 mg/day orally during that period. Treatment with the ointment alone did not give higher cure rates than the average of reported cure rates for griseofulvin alone. However, the results of treatment with 40% urea and 1% bifonazole ointment concomitantly with oral griseofulvin seemed superior to those of either of these agents alone, with full cure, partial cure and failure in group A of 22.2, 33.3 and 44.5%, respectively, and in group B, 45.4, 27.3 and 27.3%. This therapeutic experiment should be repeated in larger series of patients.

Administration, Oral↗
PubMed1992

A randomized trial of intrahepatic infusion of fluorodeoxyuridine with dexamethasone versus fluorodeoxyuridine alone in the treatment of metastatic colorectal cancer.

To decrease the toxicity of hepatic arterial fluorodeoxyuridine (FUDR) administered through an Infusaid pump (Shiley Infusaid, Inc., Norwood, MA), 50 patients with liver metastases from colorectal cancer were selected randomly to receive FUDR, 0.3 mg/kg/d, for 14 of 28 days, with or without a total dose of 20 mg of hepatic arterial dexamethasone for 14 of 28 days. Patients were stratified according to the percentage of liver involvement by tumor and the perfusion pattern on macroaggrated albumin perfusion scan (MAA) scan. There was a trend toward decreased frequency of bilirubin levels in the group receiving dexamethasone plus FUDR versus the group receiving FUDR alone (9% and 30%, respectively, had a 200% or greater increase from baseline; P = 0.07). Patients in the group treated with dexamethasone and FUDR received higher doses of FUDR in the second, third, fifth, and sixth months than those receiving FUDR alone; however, this was statistically significant only in the fifth month (percentages of planned dose received: 42% and 19%, respectively; P = 0.05), and there was no overall difference for the total 6-month period. The complete and partial response rates were increased in patients receiving dexamethasone and FUDR versus FUDR alone (8% and 63% versus 4% and 36%, respectively; P = 0.03), and there was a trend toward increased survival with the addition of dexamethasone (median, 23 months and 15 months, respectively; P = 0.06). In conclusion, the use of hepatic arterial dexamethasone is associated with an increased response rate and a trend toward increased survival and decreased bilirubin levels. Therefore, the authors recommend additional investigation of the use of dexamethasone with chemotherapy to treat hepatic metastases.

Adult↗
PubMed1992

Analysis of premature ventricular counts in long term ECG following myocardial infarction.

Frequent and recurrent ventricular premature beats (VPB's) are considered to be associated with a higher risk of sudden cardiac death, particularly for survivors of myocardial infarction (MI). The distribution of VPB's has a large probability mass at zero, and a very heavy right hand tail. In this research, we fitted a model to VPB for patients for which VPB was present. The model was fitted on the basis of a relatively large data set on MI survivors in Israel. The model was fitted by a method which is based on the generalized linear model. This method, which was introduced by Zeger and Liang, is designed for longitudinal data and uses the quasi-likelihood concept. No specific assumptions are required on the shape of the distribution of the dependent variable. The results indicate that the model fits the data quite well but underestimates the very extreme high values. This research demonstrates the applicability of generalized linear models for longitudinal non-Gaussian data. Such data often arise in medical studies. The study also points out the distributional properties of VPB counts. In particular, it shows their associations with simple clinical and epidemiological variables, and with certain time periods during the day.

Cardiac Complexes, Premature↗