PubMed Health⌕ Search

Biomedical subjects

F Larsen

Publications and source records attributed to F Larsen.

88 records · Page 5Linked to original sources
PubMed1986

Autoreactive lymphocytes in thyroid disorders. Quantitation of anti-thyroglobulin antibody formation by a specific haemolytic plaque forming cell (PFC) assay.

Blood mononuclear cells (MNC) from 21 patients with autoimmune thyroiditis were assayed for secretion of immunoglobulins in vitro by a reverse haemolytic plaque forming cell (PFC) assay. An antigen-specific assay was employed to quantify anti-thyroglobulin antibody (TgAb) secreting cells. The sensitivities of the two PFC assays were similar. The antigen specificity of the Tg-PFC assay was demonstrated by the ability of free Tg to inhibit PFC formation. The number of spontaneous TgAb-secreting cells was low (median 3 IgG-Tg-PFC/10(6), range 0-35/10(6)); TgAb activity was found in 3% (range 0-11%) of total IgG-PFC. The number of spontaneous IgG-TgAb-secreting cells correlated positively to TgAb titres in serum. MNC from most patients secreted IgG-TgAb upon polyclonal stimulation in vitro for six days with pokeweed mitogen (52 IgG-Tg-PFC/10(6), range 0-478/10(6)); TgAb activity was found among 2% (range 0-8%) of total IgG-PFC. Again, pokeweed mitogen-induced TgAb secretion correlated positively to TgAb titres in serum. Finally, MNC from most patients secreted TgAb after culture with Tg. The Tg-induced response was about 1/3 of the pokeweed mitogen-induced TgAb response. Tg did not increase the production of total IgG indicating that Tg is not a polyclonal stimulus. Few TgAb-secreting MNC were discovered in euthyroid sex and age-matched control patients.

Aged↗
PubMed1986

Autoreactive lymphocytes in thyroid disorders. II. Comparison of anti-thyroglobulin antibody production by plaque-forming cell, radio-immunological and enzyme-linked immunosorbent assays.

Blood mononuclear cells (MNC) from 9 randomly selected patients with autoimmune thyroiditis were stimulated in vitro with pokeweed mitogen (PWM), a polyclonal B lymphocyte activator. The secretion of immunoglobulins (Ig) and anti-thyroglobulin antibodies (TgAb) was assayed by means of haemolytic plaque-forming cell (PFC) assays, radio-immune assay (RIA) and enzyme-linked immunosorbent assays (ELISA). Total Ig and TgAb production was maximal using MNC cultured at 1.0 X 10(6)/ml as estimated by PFC, RIA and ELISA. The Ig and TgAb production as measured by RIA and ELISA was 1.5 - 3 times higher after 12 days' culture compared to 6 days' culture. Ig and TgAb production measured by PFC-assays at day 6 correlated positively to the results obtained by RIA and ELISA at day 12. PWM-induced TgAb secretion correlated positively to TgAb titres in serum. As judged by PFC, TgAb production was found in 8/9 patients; about 5% (range 0 - 7.9%) of the total PWM-stimulated IgG-secreting cells were involved in TgAb secretion. TgAb production as measured by ELISA and RIA was found in 6/9 patients. By reference to an affinity-purified human TgAb preparation, the TgAb secretion was about 0.7% (range 0 - 21.3%) of the total PWM-induced IgG secretion.

Antibody Formation↗
PubMed1985

Release patterns of CK-MB and mitochondrial CK following myocardial ischaemia.

Following myocardial damage as in acute myocardial infarction (AMI) or open heart surgery, the tissue damage might result in a release of mitochondrial CK (CK-MIT). The presence of this CK isoenzyme in serum may be detected after chromatographic separation of CK-activity on Sephacryl S-200. By combining chromatographic separation of CK-MB with immunologic inhibition of CK-M, both CK-MB and CK-MIT can be estimated in serum. Using this procedure changes in enzyme activities were studied in ten patients with AMI and twelve patients subjected to open heart surgery using cardioplegia. Following AMI CK-MB peaked about 24 h after onset of ischaemic symptoms. CK-MIT increased similarly and reached a plateau after 24 h where it remained during an additional 24-36 h. At peak CK-MB concentration, the corresponding CK-MIT activity was about 22% of the CK-MB activity. Following cardiac surgery there was a rapid release of CK-MB with a peak about 5 h after release of aortic cross-clamping, and with a simultaneous CK-MIT activity amounting to 19% of the CK-MB activity. In conclusion, CK-MIT is released into serum following myocardial ischaemia. Its appearance has time characteristics similar to that of other mitochondrial enzymes. The CK-B method does not specifically determine CK-B, but non-CK-M, which in cardiac ischaemia at peak serum CK-MB concentrations includes about 20% CK-MIT.

Adult↗
PubMed1984

Differential hemispheric activation during complex visuomotor performance: alpha trends and theta.

Two experiments were done to study asymmetry in left and right cerebral hemispheres while subjects performed in verbal and nonverbal tasks, including a complex visuomotor T.V. tennis game (Pong). Previous analyses demonstrated asymmetries of alpha activity during these tasks, and in this paper we describe sequential changes of alpha asymmetry associated with playing Pong. Alpha power was stable in the left hemisphere but decreased in the right hemisphere during each rally, returning to symmetry during inter-rally intervals. Theta activity increased bilaterally in most of the tasks and differed from the alpha patterns in several respects. The second experiment demonstrated the usefulness of video games for assessing sex and age differences in visuospatial capacities'--male performance was better than female and performance was inversely related to age.

Aging↗
PubMed1983

Serum creatine kinase in obese subjects before and during weight reduction.

Obese subjects are at increased risk for cardiovascular disease manifestations. The CK value is an important aid in the diagnosis of myocardial infarction, but may also be increased by factors such as muscle mass or breakdown of muscle tissue. We analysed CK values in 120 obese patients in our Obesity Unit and also monitored CK values during a weight reduction programme in 26 of these patients. CK values did not increase with body weight, and during weight loss in a diet programme no systematic CK changes were observed. We conclude that in the evaluation of an elevated CK value in a coronary care unit, such an increased value cannot be accounted for by the overweight per se.

Adolescent↗
PubMed1983

Suppression and stimulation of TSH and thyroid hormones in bulls during starvation and refeeding.

Sixteen bull calves were fasted during two periods, 31/2 and 7 months old. Blood samples were taken every 6 h during an experimental period of 9 days: 2 control days, 5 fasting days and 2 refeeding days. During the control days with ad libitum feeding, T3, T4 and TSH increased during the day. During the fasting period, T4 decreased with a half-life of 3.5 days and T3 with a half-life of 3 days. TSH decreased in a less regularly way to a mean of 60% of control mean. Six h after refeeding, TSH had increased to 300% of control mean. T3 and T4 had a maximum 12 h after refeeding. As the T4 decreased with a rate nearly similar to the T4 disappearance rate in starving bulls, the secretion of T4 from the thyroid gland must have been almost stopped during the starvation period. The morning values were below normal for all three hormones after 2 days of refeeding.

Animals↗
PubMed1980

Birth complications and the distribution of handedness.

In an attempt to clarify the relationship between self-reported birth complications and handedness, the handedness distributions of 181 college students who reported birth complications and 1320 students who reported no complications were compared. The results suggest a clear but modest shift in the birth complications group away from the dextral end of the continuum. However these data did not validate the hypothesis that left-handedness results from birth complications.

Adolescent↗
PubMed1980

Reliability of seasonal variation in births of left-handed women.

Recently Leviton and Kilty reported that the birth dates of left-handed girls in elementary school display a seasonal trend which peaks in November. We report here a failure to replicate this finding for 257 male and 323 female college students. Further, we have considered the likelihood that the original finding was due to sampling error rather than speculating that environmental factors associated with the season of birth are implicated in the etiology of left-handedness, as Leviton and Kilty have stated.

Birth Rate↗
PubMed1977

Interactions between delta9-tetrahydrocannabinol and phencyclidine hydrochloride in rats.

delta9-Tetrahydrocannabinol (THC; 2.5, 5.0, 10.0 mg/kg, PO) impaired avoidance and rotarod performance, and caused bradycardia and hypothermia. Phencyclidine (PCP; 1.25, 2.5, 5.0 mg/kg, IP) impaired avoidance and rotarod performance and caused a marked increase in photocell activity. When combined, the depressant properties of each drug were enhanced and the stimulation of photocell activity cg/kg THC and its interactions with PCP followed subacute treatment for six days, whereas many of the effects of PCP were enhanced after subacute treatment with a dose of 2.5 mg/kg. Open-field behavior was affected by each drug alone and in combination in a similar way as photocell activity, but the depression caused by their interaction was greater; both drugs caused an increase in urination. Response rates on an FR-10 schedule of food reinforcement were decreased by 2.5 mg/kg PCP, but not by 5.0 mg/kg THC; the combination caused greater response suppression than either drug alone. The functional interactions between THC and PCP were not related to changes in the concentrations of 14C or 3H in plasma or brain derived from 14C-delta9-THC and 3H-PCP, respectively.

Animals↗
PubMedDate not supplied

Isolation of human erythrocyte acetylcholinesterase using phase separation with Triton X-114 and monoclonal immunosorbent chromatography.

A generally applicable approach to the preparative isolation of amphiphilic membrane proteins that follow the Triton X-114 phase during a temperature-dependent phase separation is described. The phase separations were performed direct on whole blood and a 650-fold purification of human erythrocyte membrane acetylcholinesterase (AchE) was obtained. Thus, 0.2 mg enzyme was isolated per 1 liter of blood, with a specific activity of 13 IU/mg, the major contaminants being glycophorin and hemoglobin. The protein material was isolated from the detergent phase by Cu2+ chelate chromatography. This material was used to raise monoclonal anti-AchE antibodies which, when applied to immunosorbent chromatography of washed Triton X-100-lysed erythrocytes in one step, allowed a 246,000-fold purification of AchE with a yield of 88% and a specific activity of 3800 IU/mg.

Acetylcholinesterase↗