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Biomedical subjects

A Ostergaard

Publications and source records attributed to A Ostergaard.

11 recordsLinked to original sources
PubMed2001

Search and selection processes in implicit and explicit word-stem completion performance in young, middle-aged, and older adults.

In the present investigation, we sought to (1) replicate previous reports of impaired word-stem completion (WSC) priming and cued recall performance in older adults, (2) gain a better understanding of the differential roles of search and selection processes in implicit and explicit WSC, and (3) determine the particular aspects of WSC performance that are influenced by age. Experiment 1 demonstrated that older adults primed and recalled fewer items on a WSC task than middle-aged adults did, who in turn primed and recalled fewer items than young adults did. A series of item analyses indicated that choice of a stem completion is influenced by two independent sources of information: the familiarity of the completion reflected by word frequency and the cue-specific match between the stem and the completion word based on the common pronunciation of the stem. Experiment 2 demonstrated that older adults utilized cue-specific matching to the same degree as young and middle-aged adults. However, the impact of target familiarity changed across the lifespan. Older adults produced and recalled high-frequency targets as well as young adults but produced and recalled fewer low-frequency targets than did young participants. The results are consistent with the view that older adults rely on familiarity to a greater degree than do young adults.

Adolescent↗
PubMed1997

Ca2+ binding to the first epidermal growth factor-like domain of factor VIIa increases amidolytic activity and tissue factor affinity.

Coagulation factor VIIa belongs to a family of homologous enzymes, including factors IXa and Xa and activated protein C, composed of two epidermal growth factor-like domains located between an N-terminal domain rich in gamma-carboxyglutamic acid residues and a C-terminal serine protease domain. The first epidermal growth factor-like domain in factor VIIa contains a Ca2+ binding site, the function of which is largely unknown. Site-directed mutagenesis of two Ca2+-liganding Asp residues in this domain abolished Ca2+ binding and resulted in a 2-3-fold decrease in amidolytic activity at optimal Ca2+ concentrations. The lower amidolytic activity persisted in complex with soluble tissue factor, apparently due to a lower kcat of the mutant factor VIIa. Mutant and wild-type factor VIIa bound to lipidated tissue factor were equally efficient activators of factor X. The dissociation constants, derived from amidolytic activity and surface plasmon resonance measurements, were 2-5 nM and 50-60 nM for the interactions between wild-type and mutant factor VIIa, respectively, and soluble tissue factor. Binding to lipidated tissue factor was characterized by dissociation constants of 7.5 pM for factor VIIa and 160 pM for the factor VIIa mutant. Hence, a functional Ca2+ binding site in the first epidermal growth factor-like domain added 7-8 kJ/mol to the total binding energy of the interaction with both lipidated and soluble tissue factor.

Aspartic Acid↗
PubMed1990

Childhood amnesia and distinctions between forms of memory: a comment on Wood, Brown, and Felton.

Recently, Wood and his colleagues (1989) presented a case of childhood amnesia as evidence against the distinction between declarative and procedural memory that has sometimes been applied to human amnesia. Their argument was based on the observation that their patient showed some progress in school over the years, i.e., acquired some declarative knowledge, despite severely impaired day-to-day memory ability. We briefly review their case, together with a carefully studied second case of childhood amnesia not mentioned by Wood et al. Their argument is wrong in several ways. First, the utility of the declarative/procedural distinction for amnesia, or the utility of any other distinction between memory systems, depends on whether or not one kind of memory is impaired selectively, not on the severity of the impairment. In particular there is no requirement that one kind of memory be totally absent. Second, they have not provided the data necessary to support their argument; namely, data showing that the amount of declarative knowledge accumulated during years in school was better than would have been expected given the capacity for moment-to-moment or day-to-day memory. Indeed, the patient's moment-to-moment memory ability is better than represented, and the patient's progress in school was abnormally slow. Third, it is not clear that academic achievement scores provide a direct measure of declarative memory abilities (skill learning and recovery of function may also have contributed). We conclude that the evidence from childhood amnesia is fully consistent with the proposal that amnesia reflects a selective impairment in the formation of long-term declarative memory.

Achievement↗
PubMed1989

Lung function and postural changes during pregnancy.

The aim of this study was to determine the effects of postural changes on lung function in pregnant women during the first, second, third trimester and post partum. A significant decrease in FRC, PEF and FEV1 was observed as a result of the postural changes. Arterial oxygenation, MVV and DLCO remained largely the same.

Adult↗
PubMed1989

Mental function in elderly men after surgery during epidural analgesia.

To evaluate whether there is a difference in mental function after general anaesthesia and epidural analgesia, a homogeneous group of 40 elderly men (age between 60 and 80) undergoing transurethral prostatectomy was studied. The study was prospective, randomised and double blind. Patients with all types of complications believed to impair mental function were excluded. Long-term, short-term, verbal and visual memory were tested preoperatively, and 4 days, and 3 weeks postoperatively. In conclusion, we found a significant and equal decline in test performance on the fourth postoperative day. Three weeks postoperatively, however, both groups had returned to or exceeded preoperative levels of performance.

Aged↗
PubMed1988

Group B streptococci in the lower urogenital tract and late abortions.

The occurrence of group B streptococci in the lower urogenital tract of 150 women with signs of abortion and 100 women with uncomplicated pregnancy was studied. Group B streptococci appeared significantly more frequently in the urine (p less than 0.001) and in the uterine cervix (p less than 0.01) of women with abortion. Delivery resulted in 85% of patients with group B streptococci in the urine and in 42% of patients with no group B streptococci (p less than 0.001). Group B streptococci were cultured from amniotic fluid from three of eight women with intact membranes and were isolated from the urine and cervix. These bacteria were antibody coated as demonstrated by an immunofluorescence technique. Group B streptococci were recovered from blood or liver in six fetuses, including two who had group B streptococci in the amniotic fluid. The study demonstrates an association between the occurrence of group B streptococci in the urine and cervix and late abortions.

Abortion, Spontaneous↗
PubMed1985

Recency and frequency judgements in alcoholic amnesics and normal people with poor memory.

Alcoholic amnesics have been reported to confuse when an event occurred with how frequently it occurred and conversely, how frequently something took place with when it happened. This lack of independence of recency and frequency judgements, shown by these amnesics (but not shown by normal people) has been interpreted as reflecting a selective amnesic failure in memory for contextual information; this failure, in turn, leading to poor recall and recognition memory. The effect is replicated on another group of Korsakoff patients and, by manipulations of retention intervals and of learning opportunity, it is also shown that normal people with memory that is as poor overall as that of amnesics still have specific contextual memory with which to make temporal judgements independently of frequency of presentation and (somewhat less obviously) frequency judgements independently of recency of presentation. The qualitative differences between amnesic and normal people cannot therefore be an artefact of testing generally poor memory in amnesics. While it is possible that the unavailability or inaccessibility of contextual information may cause amnesia, an alternative hypothesis, that poor contextual knowledge is an incidental feature in alcoholic amnesia (related to frontal lobe dysfunction), is also considered.

Alcohol Amnestic Disorder↗
PubMed1978

Polyglycolic acid versus chromic catgut in bladder surgery.

The clinical importance of calcified deposits on sutures in bladder surgery was evaluated in a blind paired randomised trial of 3/0 chromic catgut versus polyglycolic acid 3/0. Cystoscopy with photographic recording was performed 8 weeks after operation in 40 patients without and 8 patients with previous or present bladder stones. None had visible calcified deposits at that time and sutures were only visible in 1 patient from each of the 2 groups without bladder stones. It was concluded that neither chromic catgut nor polyglycolic acid sutures carry any significant risk of bladder stone formation, whether infection is present or not; the conclusion includes both patients with and without previous bladder stones, but is less firm in the former because of the small number of patients studied.

Bacteriuria↗
PubMedDate not supplied

Evaluation of the barium-enema examination and colonoscopy in diagnosis of colonic cancer.

The diagnostic value of colonoscopy was investigated in 123 patients with certain or questionable cancer of the colon as demonstrated by an ordinary barium-enema examination. The diagnosis was revised by laparotomy or clinical follow-up studies in cases of patients having no operation. The following conclusions were deduced: 1) The number of unnecessary laparotomies may be reduced by doing colonoscopy in patients with certain or questionable cancer of the colon as demonstrated by ordinary barium-enema studies. 2) The gain in diagnostic value of adding a colonoscopy to a barium-enema examination is more pronounced in patients with questionable than in those with certain cancer as visualized by the barium-enema studies. 3) The risk of missing a cancer of the colon during colonoscopy is very small if an experienced examiner looking for cancer performs the colonoscopy. 4) Colonoscopy is of little diagnostic value in cases of patients who have radiologic evidence of stenosis of the sigmoid colon. 5) The number of patients selected for colonoscopy on the basis of radiologic evidence suggesting cancer probably can be reduced by refinement of the barium-enema examination.

Adult↗