Search PubMed⌕ Search

Biomedical subjects

L H Larsen

Publications and source records attributed to L H Larsen.

At least 37 records · Page 2Linked to original sources
PubMed1992

EEG markers of early Alzheimer's disease in computer selected tonic REM sleep.

All night sleep/wake EEGs were examined for diagnostic features sensitive to early Alzheimer's disease (AD) using computer automated techniques. Thirty-nine mild AD patients and 43 normal controls underwent 9 h of EEG recording in the sleep laboratory. All-night EEGs were screened for ideal, low artifact tonic REM sleep using autoregressive and power spectral techniques. The frequency spectra during tonic REM sleep revealed a significant shift towards slower wave forms in AD vs. control subjects. Beta (greater than 12 Hz) was reduced and theta and delta (2-8 Hz) increased in AD compared to control groups. This frequency shift was demonstrated by several analytic techniques, including binned spectral energies and unique zones in the frequency spectra. Discriminant analyses using optimal binned EEG variables correctly classified 74% of AD and 98% of control subjects, and unique zone scores correctly classified 92% of AD and 95% of control subjects, indicating that these sleep EEG changes are apparently predictive of AD status.

Aged↗
PubMed1991

EKG artifacts suppression from the EEG.

A method is proposed to identify and eliminate EKG artifacts from a single channel of EEG recordings. The method identifies the EKG as outlying data in the EEG. The algorithm may be applied universally to all EEG recordings.

Algorithms↗
PubMed1991

Healthy elderly women and men have different entrained circadian temperature rhythms.

Body core temperature was measured in healthy elderly men and women under entrained conditions. Female subjects showed a larger amplitude and a higher peak temperature than male subjects. In addition, acrophase was advanced for females by an average of 49 minutes. Variability in acrophase was greater for males than females. This pattern of gender differences varies considerably from the pattern others have observed in young subjects, suggesting that aging may affect the circadian timing system of males and females differently.

Aged↗
PubMed1979

Age and sex specific reference limits for carbohydrate tolerance.

Glucose estimations in the absence of diabetic symptoms may lead to diagnostic problems when clinicians are confronted with borderline results. This study on 28 581 estimations of post-prandial plasma glucose values gives age and sex specific reference limits derived from regression analysis at the 97.5 percentage point. A linear relationship exists between age and glucose tolerance in both sexes which is affected by the time of specimen collection. No evidence was found in support of bimodality; hence, it is believed that the observed diminution of carbohydrate tolerance with age is characteristic of the entire population.

Adult↗
PubMed1979

Evaluation of automated multiphasic health testing in the survey of the north-west region of Melbourne.

The results of automated multiphasic health testing (AMHT) in a randomly selected population of 664 subjects are reported. AMHT revealed a number of conditions that had not been diagnosed previously. A total of 535 newly diagnosed conditions in 301 patients could be attributed to the survey. The yield of new diagnoses by AMHT was not affected by previous surgery attendance or by attendance intervals. Follow-up over one year revealed that treatment was recommended for 342 of the 535 newly diagnosed conditions and that the response was satisfactory in 189 (55%), but the "uncertain" response of 124 (36%) should be investigated by more thorough follow-up in future projects. It is concluded that AMHT is beneficial because of the amount of information that is revealed, because of the financial value and because of the benefit to patients.

Adult↗
PubMed1977

Evaluation of automated multiphasic health testing of referred patients by general practitioners.

Seventy-eight general practitioners provided clinical follow-up reports on 752 patients whom they had referred to the Shepherd Foundation, Melbourne, for automated multiphasic health tests (AMHT). One or more new diagnoses were reported in 270 cases (36%). The yield of new diagnoses made as a result of AMHT was a function of sex, but not of age or pre-referral status. Additional useful information relevant to a previously known diagnosis was reported in 234 cases (31%) and other benefits in 185 cases (25%). Patients were significantly reassured in 623 cases (83%) while disadvantages were reported in 41 cases (5%).

Adult↗
PubMed1976

The collagenous and non-collagenous protein of the canine intervertebral disc and their variation with age, spinal level and breed.

The total nitrogen, collagen and non-collagenous protein (NCP) content of the nucleus pulposus (NP), transitional zone (TZ) and annulus fibrosus (AF) of the beagle (a chondrodystrophoid breed) and greyhound (a non-chondrodystrophoid breed) intervertebral discs have been determined over the age range birth to 124 months. Discs were sampled at three spinal levels - lumbosacral, lumbar and thoracic regions. The beagle NP attains an average NP collagen content of 25% dry weight before 11 months of age, whereas the greyhound NP content is less than 5% collagen for most of its life. The NCP of the young greyhound disc is greater than that of the beagle of corresponding age. Plots of the ratio of collagen/NCP for discal regions at various ages highlight the large differences between the two breeds of dog. It is suggested that these differences in protein distribution are related to the elevated incidence of intervertebral disc prolapse in the beagle.

Aging↗
PubMed1976

A comparative chemical and histochemical study of the chondrodystrophoid and nonchondrodystrophoid canine intervertebral disc.

The chemical composition of the intervertebral disc of 9-month-old chondrodystrophoid and nonchondrodystrophoid dogs was studied for collagen, noncollagenous protein and glycosaminoglycan. Content of these substances differed significantly between breeds. The differences were most marked in the nucleus pulposus; the noncollagenous protein content of the nonchondrodystrophoid breed was higher than in that of the chondrodystrophoid dogs. The total nitrogen value of the nonchondrodystrophoid nuclei pulposi was less than that of the corresponding chondrodystrophoid discs mainly because of the high collagen content of the latter discs. Histochemically, it was found that the nuclei pulposi of the nonchondrodystrophoid breed contains larger amounts of glycosaminoglycan than in the discs of the chondrodystrophoid breeds.

Animals↗
PubMed1976

The qualitative assessment of glycosaminoglycans in the canine intervertebral disc using a critical electrolyte concentration staining technique.

Through the use of a critical electrolyte concentration staining technique, the glycosaminoglycans (GAGs) in the nucleus pulposus region of the canine intervertebral disc were arbitrarily identified as "hyaluronic acid", chondroitin sulphate and keratan sulphate. Approximate estimates of GAG concentration could be qualitatively deduced by determining the appropriate GAG "ALCIANOPHILIC INDEX". This index was considered to be an effective qualitative adjunct to chemical quantitation of GAGs in the intervertebral disc.

Alcian Blue↗
PubMed1975

Hepatitis B antibody in conventional gamma-globulin.

Recent lots of conventional gamma-globulin prepared from the plasma of outdated blood collected from voluntary donors in Massachusetts contain substantially more antibody (anti-HBs) to the hepatitis B surface antigen (HBs Ag) than do lots manufactured from plasma collected before 1970. Variations in titer of anti-HBs may have been related in part to local variations in the incidence of hepatitis B. However, data available since 1949 suggest that one must consider whether antibody excess (anti-HBs) or antigen excess (HBs Ag) prevailed among individuals contributing to the plasma pools. The titers of anti-HBs have continued to rise since 1971, when screening of blood donors for HBs Ag became mandatory, a step which presumably resulted in the removal of much of the HBs Ag that would otherwise adsorb anti-HBs. The anti-HBs titer in gamma-globulin routinely produced in Massachusetts now equals or exceeds the titer in other lots of gamma-globulin found to be effective in recent studies of preexposure prophylaxis of hepatitis B.

Antibodies, Viral↗