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Biomedical subjects

A Wyler

Publications and source records attributed to A Wyler.

13 recordsLinked to original sources
PubMed1998

Non-coding DNA can regulate gene transcription by its base pair's distribution.

In this paper we show that the gene transcription velocity can depend exponentially on the first moments of the base pair distribution in DNA. As the major fraction of the DNA of eucaryotes consists of non-coding sequences of base pairs and these determine the statistical characteristics of the base pair's ordering, non-coding DNA plays an important role in the functioning of the genetic apparatus. In particular, it enables a new independent mechanism for the gradual regulation of gene expression in eucaryotes.

Animals↗
PubMed1997

Reorganization of verbal memory function in early onset left temporal lobe epilepsy.

The purpose of this investigation was to examine the issue of reorganization of verbal memory function following early insult to the left mesial temporal region. It was hypothesized that reorganization of memory function was most likely to occur in those patients with an early age of seizure onset who have a more limited degree of extra-hippocampal neuropathology. Fifty-four patients with epilepsy of unequivocal left temporal lobe origin were classified into four groups on the basis of the presence/absence of hippocampal sclerosis and degree of postoperative seizure relief. Measures of verbal learning and memory as well as nonmemory measures were administered both before and 6 to 8 months after anterior temporal lobectomy. Findings were consistent with the reorganization proposal. The clinical and theoretical significance of the findings are discussed.

Adult↗
PubMed1996

The effects of human hippocampal resection on the serial position curve.

The purpose of this study was to examine the contribution of the human hippocampal formation to the classic serial position curve. Seventy-seven patients who underwent anterior temporal lobectomy (ATL) (47 left, 30 right) were administered a list learning task before and after surgery, and changes in the serial position curve were examined. Forty nonsurgical patients with complex partial seizures were tested at comparable intervals and served as controls. Changes in the serial position curve were seen only after left ATL, and almost exclusively among patients without hippocampal sclerosis. Patients without left hippocampal sclerosis, and who therefore underwent resection of hippocampus that was to a considerable degree structurally (and presumably functionally) intact, showed significant declines in recall from the primacy and middle portions of the list compared to all other groups. There was no change in the recency portion of the list. Patients with left hippocampal sclerosis showed only a modest decline in recall from the middle region compared only to the control group, and the right ATL groups did not show any significant changes in serial position recall. These findings demonstrate the contribution of the left hippocampus to those discrete portions of the serial position curve which rely on secondary memory, and have implications for assessing the effects of ATL on memory function.

Adult↗
PubMed1995

Age as a factor in identifying young adult chronic patients who are difficult to treat.

Age younger than 35 years has been used as a factor in identifying young adult chronic mentally ill patients, a group considered difficult to treat due to their rebelliousness, lack of insight about their mental illness, and increased likelihood of showing symptoms of borderline or antisocial personality disorder. In a sample of psychiatric outpatients, the authors found that a subgroup of patients under age 35 fit this profile, while other patients under age 35 and nearly all patients over age 35 did not. The authors conclude that age is a legitimate factor in identifying a subgroup of challenging patients and that such patients may outgrow many troublesome characteristics as they age.

Adult↗
PubMed1994

Development and validation of a Multiple Ability Self-Report Questionnaire.

We present results from three studies on the development and validation of the Multiple Ability Self-Report Questionnaire (MASQ), a self-report measure comprising items from five cognitive domains; language, visuo-perceptual, verbal memory, visual memory, and attention. In Study 1, we determined the content relevance of the questionnaire items. In Study 2, we assessed the basic psychometric properties (i.e., internal consistency and test-retest reliability) of the MASQ in 118 individuals without neurologic or psychiatric disorder, aged 25 to 88 years. In Study 3 we provide validity data for the MASQ by comparing the ratings of normals to people with unilateral temporal-lobe epilepsy, and examining the relationship of self-report to objective test performance. The potential use of the MASQ to study the neurologic and psychological correlates of accuracy and unawareness in self-appraisal across different cognitive domains and various clinical groups is discussed.

Adult↗
PubMed1993

Verbal recognition memory performance in unilateral temporal lobe epilepsy.

Recognition memory performance of 91 left and right unilateral temporal lobe epilepsy (TLE) patients was examined prior to and post anterior temporal lobectomy. The left TLE group showed more impaired response discrimination ability than the right TLE group; however, their false positive rate varied as a function of distractor type. Prior to temporal lobe resection, false positives were higher for semantically related distractors (novel or from an interference list) than for semantically unrelated items from an interference list, phonemic distractors, or unrelated errors. Following temporal lobe resection, only novel semantically related distractors in the left TLE group showed a significant increase in false positives, and they were also significantly higher than all other error types. The results of this study suggest that the left TLE patients have impaired individual item recollection in the context of intact information about basic semantic attributes.

Adult↗
PubMed1993

Unequivocal determination of sire allele origin for multiallelic microsatellites when only the sire and progeny are genotyped.

The effect of a segregating economic trait locus (ETL) can be detected with the aid of a linked genetic marker, if specific alleles of each locus are in association among the individuals genotyped for the genetic marker. For dairy cattle this can be achieved by application of the 'granddaughter design'. If only the sires and their sons are genotyped for the genetic markers, then the allele origin of sons having the same genotypes as their sires cannot be determined. Seven sires and 101 sons were genotyped for five microsatellites. The mean frequency of heterozygous sires was 77%. The mean number of alleles per locus was 8.2. Frequency of informative sons per locus ranged from 60% to 80% with a mean of 72%. With highly polymorphic microsatellites, at least 60% more grandsire families can be included in the analysis, and the number of sons assayed can be reduced by 40%, as compared to diallelic markers.

Alleles↗
PubMed1993

Young adult chronic patients: empirical results on subgroups and age.

The discussion about young adult chronic patients (YACPs) started in the literature in the early eighties. However, the insufficient operationalization of the YACP concept provoked some criticism. The aim of the present study was to examine whether there were operational differences between YACPs and older chronic patients, as well as between hypothesized subgroups. The results show, as expected, that the differences between YACPs and older patients correlate with age. But only the 'high-energy, high-demand' subgroup differs not only from the other YACPs but also from the older chronic patients concerning psychopathology, social functioning and their interaction with the social environment. After 35 they grow out of their typical behavior which is strongly determined by traits of borderline and antisocial personality disorder. The stigmatizing YACP label should therefore be replaced by a more precise description such as 'young long-term patients with borderline or antisocial personality traits'.

Adolescent↗
PubMed1992

Tensile testing of tubular vascular grafts produced by thermal compression fusion of flat collagenous materials.

A novel process of fusion bonding for the production of vascular grafts has been investigated. This process, based on the application of pressure and heat in a sophisticated way, has been used for the bonding of the longitudinal edges of flat dermal sheep collagen into tubular forms. The method produces continuous overlapping joints which are expected to overcome the problem of coagulation, as occurs in grafts produced by suturing. The values of the measured shear strength of the bond vary from 750 +/- 30 kPa to 940 +/- 32 kPa, depending on tube diameter and overlap length (n = 5). These values are much higher than calculated values of the stress in thin-walled tubes caused by a high static blood pressure, indicating a high safety factor for the fusion-bonded vascular grafts.

Biocompatible Materials↗
PubMed1987

Memory and head injury severity.

One hundred and two consecutive head injured patients were studied at 1 and 12 months after injury. Their performances were compared with a group of uninjured friends. The results indicate that impairment in memory depends on the type of task used, time from injury to testing, and on the severity of head injury (that is, degree of impaired consciousness). Head injury severity indices are more closely related to behavioural outcome early as compared with later after injury. At 1 year, only those with deep or prolonged impaired consciousness (as represented by greater than 1 day of coma, Glasgow Coma Scale of 8 or less, and post traumatic amnesia of 2 weeks or greater) are performing significantly worse than comparison subjects.

Adult↗
PubMed1983

[What determines the prognosis following cholecystectomy: anamnesis, surgical findings, postoperative complications?].

In 346 patients followed up 6, 12, 24 and 48 months after cholecystectomy the clinical results (VISICK and self-assessment) were very good in over 80%, 1% had symptoms due to organic disturbances and 15-20% had mostly mild symptoms (pain, fullness, food tolerance) without detectable causes. These functional disorders were found frequently in female patients with long preoperative history and frequent attacks of pain. Age of patient, character of pain, therapy before the operation, postoperative complications or change of body weight showed no correlation with later results. The results were almost always good in patients with acute pancreatitis or acute cholecystitis before the operation, or who underwent choledochotomy.

Age Factors↗
PubMed1983

Head injury in the Pacific Northwest.

This report describes 451 consecutive patients admitted to a regional trauma center with head injury over 1 year's time. Our results replicate findings from other hospital- and population-based studies of head trauma. Males exceeded females by 3 to 1; the most frequent age of patients was between 15 and 24 years; and motor vehicles were the most common cause of injuries. Mortality was related inversely to Glasgow coma scale (GCS) scores and directly to age. This study also points out two current problems in head trauma research. One is the difficulty in using the GCS in a community with highly sophisticated emergency medical services. In 38% of the patients, one or more GCS components could not be assessed directly. In 17% of cases, GCS scores could not be confidently assigned. This was principally because endotracheal tubes were in place before arrival at the hospital, precluding determination of the verbal response. A second problem is the influence of chronic pre-existing central nervous system conditions on head outcome. Twenty-nine per cent of our patients had one or more such conditions at the time of their injury. Minimal estimates of prevalence ranged from 1% (mental retardation) to 18% (alcoholism).

Adolescent↗