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P Berg

Publications and source records attributed to P Berg.

At least 127 records · Page 7Linked to original sources
PubMed1991

The waltzing oddball.

We investigated whether task relevance and probability interact to influence P3 amplitude. High and low tones were presented in random order with equal probability. In the control condition (standard oddball), every high tone had to be counted. In the waltz condition, high tones had to be counted only if they were preceded by two other high tones. It was predicted that the P3s evoked by targets in the waltz condition would be larger than the P3s evoked by the same sequence of targets in the oddball condition. That is, the frequency of occurrence of the targets should have an effect on P3, in addition to effects of the frequency of stimulus occurrence and stimulus task relevance (target/nontarget). This prediction was upheld. However, the largest P3s were evoked by nontargets following two high tones in the waltz condition. These P3s had a more anterior topographic maximum than usual. We contend that these anterior P3s reflect the interruption of an ongoing task and cannot be easily fit into the framework of the two concepts of task relevance and probability.

Adult↗
PubMed1991

Repair of deletions and double-strand gaps by homologous recombination in a mammalian in vitro system.

We have designed an in vitro system using mammalian nuclear extracts, or fractions derived from them, that can restore the sequences missing at double-strand breaks (gaps) or in deletions. The recombination substrates consist of (i) recipient DNA, pSV2neo with gaps or deletions ranging from 70 to 390 bp in the neo sequence, and (ii) donor DNAs with either complete homology to the recipient (pSV2neo) or plasmids whose homology with pSV2neo is limited to a 1.0- to 1.3-kbp neo segment spanning the gaps or deletions. Incubation of these substrates with various enzyme fractions results in repair of the recipient DNA's disrupted neo gene. The recombinational repair was monitored by transforming recA Escherichia coli to kanamycin resistance and by a new assay which measures the extent of DNA strand transfer from the donor substrate to the recipient DNA. Thus, either streptavidin- or antidigoxigenin-tagged beads are used to separate the biotinylated or digoxigeninylated recipient DNA, respectively, after incubation with the isotopically labeled donor DNA. In contrast to the transfection assay, the DNA strand transfer measurements are direct, quantitative, rapid, and easy, and they provide starting material for the characterization of the recombination products and intermediates. Accordingly, DNA bound to beads serves as a suitable template for the polymerase chain reaction. With appropriate pairs of oligonucleotide primers, we have confirmed that both gaps and deletions are fully repaired, that deletions can be transferred from the recipient DNA to the donor's intact neo sequence, and that cointegrant molecules containing donor and recipient DNA sequences are formed.

Animals↗
PubMed1991

A lateral skin incision reduces peripatellar dysaesthesia after knee surgery.

In a series of 64 ligamentous injuries of the knee, 33 were explored through a medial incision and 31 through a long lateral incision. Sensibility of the skin, the occurrence of neuromas, and discomfort during kneeling were evaluated three and six years postoperatively. The lateral incisions produced less dysaesthesia, fewer neuromas and less discomfort on kneeling.

Dermatologic Surgical Procedures↗
PubMed1991

Transurethral balloon dilatation of the prostatic urethra: effectiveness in highly selected patients with prostatism.

Transurethral balloon dilatation of the prostate has been shown to be a safe and potentially effective alternative to surgery in the treatment of benign prostatic hyperplasia, with a 66% success rate in relatively unselected patients. This study hypothesized that more careful patient selection might result in a significantly better rate of improvement. Ninety-one subjects with symptoms and signs of prostatism attributable to benign prostatic hyperplasia were studied. Group 1 comprised 42 patients with an initial mean symptom score of 16.8, residual urine of 249 ml, maximal flow rate of 7.9 ml/sec, and nomogram of maximal flow rate of -1.5. Group 2 comprised 49 less symptomatic patients with an initial mean symptom score of 14.5, residual urine of 105 ml, maximal flow rate of 10.7 ml/sec, and nomogram of maximal flow rate of -0.8. The difference in mean age and prostate size between groups was not statistically significant, but differences in baseline symptom score, residual urine, maximal flow rate, and nomogram of maximal flow rate were significant (p less than .04). Transurethral balloon dilatation of the prostate was performed under local anesthesia or IV sedation and analgesia with single-or double-balloon catheters with maximal diameters of 25-30 mm inflated to 2.5-4.0 atmospheres pressure for 10 min. Patients were followed up with repeat symptom scoring, uroflometry, and measurement of residual urine. After a mean follow-up of 22 months (range, 6-48 months), an improvement in symptom score was seen in 80% of group 2 patients compared with 43% in group 1. Improvement in symptom scores was statistically significant in both groups (p less than .04). We conclude that transurethral balloon dilatation of the prostate is more effective in patients with more moderate symptoms and with less marked signs of obstruction than in patients with more marked prostatism.

Aged↗
PubMed1990

[Measurement of the sealing impression during the cerclage operation].

In hypotensive or hypertensive eyes (i.e., in the treatment of perforating injuries), choosing an ideal length for the plaque is often difficult. The goal of the procedure is to achieve a sufficient depth of the impression. However, excessive depth must be avoided, since this could lead to String syndrome and scleral necrosis. On the basis of an analysis of ocular geometry it proved possible to calculate the circumference of the globe in the region of the cerclage, and from this the ideal length of the plaque. When silicone foam plaques are used it is between 70.4 mm when attached close to the muscle insertion and a maximum of 74.1 mm when placed on the equator of the bulb. Basing surgery on this calculation method in more than 300 patients, no complications such as String syndrome, scleral necrosis or secondary glaucoma were observed. A chronic inflammatory reaction to the scleral buckle was seen in three cases. In order to avoid this complication, caused by the enormous volume of the cylindrical silicone plaque, splitting or flattening of the plaque is recommended.

Humans↗
PubMed1990

[Surgical therapy of uveitis].

Cryotherapy is a good method of treating chronic uveitis, because it is minimally invasive and there are normally no complications. It has proved possible to reduce the frequency and intensity of inflammatory episodes, so that in many cases systemic drug therapy is superfluous. Stabilization or even regression of secondary conditions such as cystoid macular edema or cataract has been achieved, a phenomenon also observed among the present authors' own patients. In cases which did not respond to cryotherapy or where there were severe vitreous opacities vitrectomy was performed. A total of 207 eyes were followed up, on average for 1 1/2 years. During this time visual acuity remained stable or improved in 76% of those treated by cryotherapy, and in over 86% of those treated by vitrectomy.

Adolescent↗
PubMed1990

Renaturation of complementary DNA strands mediated by purified mammalian heterogeneous nuclear ribonucleoprotein A1 protein: implications for a mechanism for rapid molecular assembly.

Purified heterogeneous nuclear ribonucleoprotein (hnRNP) A1 protein, which is found in vivo associated with heterogeneous nuclear RNA (hnRNA), promotes the rapid renaturation of nucleic acid strands. Maximal renaturation activity requires the glycine-rich carboxyl-terminal one-third of the protein, although the amino-terminal two-thirds also has activity. The A1-mediated reaction is second-order with respect to complementary DNA concentration, and the renaturation rate constant at 37 degrees C with A1 is about 3000-fold greater than in the absence of the protein. At 60 degrees C, the A1-mediated renaturation rate is even faster, and is about 300-fold greater than protein-free reactions carried out at 68 degrees C in 1 M NaCl. Provided that sufficient A1 protein is present to coat all strands in solution, the presence of nonhomologous, single-stranded DNA does not significantly inhibit the reaction. Moreover, renaturation of short strands to their complement contained in very long strands is nearly as efficient as between two short strands. These results indicate that A1 may be useful for procedures that rely on nucleic acid renaturation. We propose that A1 promotes rapid renaturation primarily by reducing the entropic barrier of bimolecular strand association through relatively transient interactions between A1-coated strands. Such interactions, mediated by flexible repeating domains, may act generally to increase the association kinetics of highly specific molecular assemblies in processes such as RNA maturation, transcription, translation, and transport.

Coliphages↗
PubMed1990

Spinal anaesthesia in day-care surgery with a 26-gauge needle.

We studied 106 day-care surgical patients (52 male) aged 18-70 yr (mean 49.6 yr) who received spinal anaesthesia with a 26-gauge spinal needle. The incidence of headache, back pain and patient acceptability were investigated after operation using a questionnaire. The incidence of postspinal headache was 7.5%, and 11.3% of patients developed back pain. One patient remained in hospital because of hypotension and dizziness. There were no major complications and patient acceptability was almost 100%. We conclude that spinal anaesthesia for day-care surgery is easy to perform and cost effective.

Adolescent↗
PubMed1990

Gene targeting at the human CD4 locus by epitope addition.

Homologous recombination at the CD4 locus in a human T-cell line has been achieved by an approach called epitope addition. The endogenous CD4 gene provided transcription, translation, and leader sequences to a crippled introduced Thy-1 gene, resulting in the expression of murine Thy-1 epitopes on the surface of the human cells. Thy-1+ cells were selected using the Fluorescence Activated Cell Sorter (FACS). An estimated 700-fold enrichment for homologous versus nonhomologous integration events was obtained, such that 70% of cells scoring positive for Thy-1 were derived from gene targeting. Three of the Thy-1+ cell lines expressed protein only from the targeted allele; thus, these cells were functionally CD4-.

Animals↗
PubMed1990

Transduction of cellular neo mRNA by retrovirus-mediated recombination.

Transduction of cellular oncogenes by retroviruses is thought to be a multistep process, involving transcriptional activation of a cellular gene by upstream proviral integration and joining of cellular DNA to retroviral transcriptional signals, followed by copackaging and recombination with a helper virus genome during reverse transcription. To examine the molecular mechanism of the reverse transcriptase-mediated recombination, we introduced into mouse fibroblast cells a variety of constructs in which the neo selectable marker was joined to flanking retroviruslike or cell-like sequences. After superinfection and copackaging with a replication-competent Mo-MuLVsupF virus, the formation of recombinant neo transducing viruses was assessed in a second round of virus infection by the ability to confer G418 resistance to infected cells. Our results showed that recombinant neo proviruses were generated from neo RNA containing either a 5' or 3' retroviral end, implying that one recombination event with helper virus RNA was sufficient to incorporate the neo gene into proviral DNA. Recombination occurred with an apparent frequency of 10(-4) to 10(-5) per replication cycle in the absence of homology between the two recombining partners. This frequency, however, increased at least 100-fold if homology was provided at the site of recombination. Our results support the hypothesis that neo-transducing viruses arise via reverse transcriptase-mediated recombination of RNA rather than by recombination proceeding through DNA intermediates. Unexpectedly, removal of the retroviral packaging site psi reduced the number of neo recombinants only slightly. Our data indicated that although RNAs lacking the psi site are poorly packaged into virions, those RNAs that are included in the virions undergo frequent recombination, even if there is no selection for recombination. Many of the neo recombinants formed with the psi- constructs had undergone additional recombinations and often incorporated the psi site from the helper RNA.

DNA, Viral↗
PubMed1990

[Duodenal leiomyoblastoma. Apropos of a new case and review of the literature].

The authors report a new case of duodenal leiomyoblastoma. Since local anatomical factors were favorable, the tumor was removed by resecting the entire second portion of duodenum with reanastomosis of the remaining ends. This case can be added to the very small number of cases reported in the literature regarding leiomyoblastoma at this site in the gastrointestinal tract. Since diagnostic is difficult, and often made per-operatively following and acute complication, a precise topographical study of the region needs to be performed. It is only by this means that a completely safe operative procedure may be chosen and performed. From an anatomo-pathological viewpoint, several criteria exist to distinguish the potentially benign from the potentially malignant form. However, this remains to be confirmed given the controversial aspects of the subject. Study has mainly involved gastric localisations where a greater number of lesions have been found. At present, only time will show whether these tumors are benign or malignant.

Cholangiography↗
PubMed1989

[Measurement of arterial pressure using 3 measurement methods in medial arterial calcification].

Medial calcification of the arteries, because of non-distensibility of the blood vessel walls, may overestimate the real intra-arterial pressure when blood pressure (BP) is measured by indirect sphygmomanometry cuff. In order to assess the best method for measuring BP, we compared direct intra-arterial measurements with indirect cuff sphygmomanometry as well as automatic oscillometric measurements in 15 hypertensive patients. Mean age +/- standard deviation (SD) was 62 +/- 9 years; all patients had medial calcifications of forearm and/or brachial arteries, and Osler's maneuver was negative in all. Ten sets of direct and indirect BP measurements were obtained for each patient. Results are expressed as mean +/- SD: (table; see text) There was no significant difference between cuff pressure and systolic intra-arterial pressure. The automatic oscillometric method underestimated systolic intra-arterial BP. Great individual variability was observed and could not be predicted clinically. Indirect diastolic BP values were greater than intra-arterial BP in all patients with the sphygmomanometer cuff and in 10 patients with the oscillometric recorder. There existed a direct relation between intra-arterial BP and differences between indirect BP measurements and intra-arterial BP as follows: intra-arterial BP was overestimated by indirect methods for values under 150 mmHg, and underestimated above 150 mmHg. In conclusion, invasive intra-arterial BP measurement seem to be necessary to distinguish between hypertensive and pseudo-hypertensive patients, in case of radiologic evidence of arterial calcification.

Aged↗
PubMed1989

[Nonspecific eye autoantibodies in uveitis].

Under certain pathologic circumstances autoantigens lead to the formation of autoantibodies. In uveitis, autoimmunologic phenomena will also be discussed. We studied 149 sera of uveitis patients for various organ specific and non-organ specific autoantibodies. We found antisarcolemal autoantibodies (ASA) mainly in patients with acute iritis (59% positive) but also in panuveitis (40%) and iridocyclitis (29%). On the other hand antiendothelial antibodies (AEA) could be found in 43% of patients with chorioretinitis. Antisinusoidal antibodies (SA) have been detected in iritis and panuveitis patients more often than in the control group which show positive autoantibodies in 5% of all cases. Using ELISA we looked for antibodies against keratin, laminin and microsomes. Because antimicrosomal-, antilaminin- and antisarcolemal-antibodies recognize the same epitope, there was a good correlation of these three autoantibodies. Similar clusters of autoantibodies (ASA, AEA and SA) have been found in various infectious diseases and in chronic inflammatory diseases in which an infectious component is discussed. These results may indicate that iritis, iridocyclitis, chorioretinitis and panuveitis are secondary reactions of eye tissue following a systemic primary disease. Especially viruses are well-known for their production of autoantibodies. In patients with intermediate uveitis we could not demonstrate these autoantibodies more often than in the control group, favouring theories which believe in an autoimmune reaction against vitreous elements.

Antibodies, Antinuclear↗
PubMed1989

[Not just a scalpel].

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Cardiac Surgical Procedures↗