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Biomedical subjects

L Hedlund

Publications and source records attributed to L Hedlund.

9 recordsLinked to original sources
PubMed1991

Diffusion/microcirculation MRI in the rat brain.

The CO2 fraction of an anesthetized rat's breathing mixture was changed (from 0 to 10%) to attempt to change the brain microcirculation and observe these changes in diffusion measurements of the neural tissue. Brain apparent diffusion coefficients were measured to be (0.71 +/- 0.01) X 10(-3) mm2/s before sacrifice and (0.39 +/- 0.01) X 10(-3) mm2/s after sacrifice. Multiple diffusion components were observed, consistent with flowing material, but the extra components did not increase with increased CO2. It is proposed that the additional components may be due to extracellular, extravascular water such as CSF.

Animals↗
PubMed1977

Melatonin: daily cycle in plasma and cerebrospinal fluid of calves.

Melatonin was measured by radioimmunoassay in jugular vein plasma and lateral ventricle cerebrospinal fluid collected from calves at 12 times of the day and night. Melatonin in cerebrospinal fluid increased 17-fold from an average (+/- standard error) of 38 +/- 8 picograms per milliliter during the day to an average of 637 +/- 133 picograms per milliliter during the night (P less than .001). Plasma concentrations of melatonin increased sixfold from an average, per milliliter, of 19 +/- 4 picograms during the day to 121 +/- 24 picograms during the night (P less than .001).

Animals↗
PubMed1977

Cerebral ventricle cannulation in the calf.

A stereotaxic apparatus and procedure for surgically implanting guide cannulae for access to the cerebral ventricles of the calf are described. This type of implant permits chronic ventricular injections and collections of mililiter quantities of cerebrospinal fluid from the nonanesthetized calf.

Anesthesia, Inhalation↗
PubMed1977

Behavior of lactating dairy cows during total confinement.

Daytime activity of four lactating Holstein cows housed in total confinement in stanchion stalls for about 14 wk was observed continuously, and activities such as eating, drinking, resting, ruminating, and socializing were recorded. Observations were by closed-circuit television and a switch panel connected to an event recorder. During the 15 h of daytime, the cows spent an average of 45% of the time lying, 26% eating, 22% ruminating, 1% drinking, and 2% socializing. Most eating occurred during standing (98.4%) while most rumination occurred during lying (59%). The distribution of these activities by time of day was similar to that of pastured dairy cows. Periods of eating, drinking, and social activity were most intense during and shortly after the morning and afternoon milking and feeding times. Conversely, periods of greatest recumbency, rumination, and rest occurred between feeding time from midday to late afternoon. Thus, in spite of prolonged total confinement, the four cows continued to exhibit behavioral activities (duration and distribution) which are typical of less confined cattle.

Animals↗
PubMed1976

Peripheral sympathetic innervation of the deep pineal gland of the golden hamster.

Both the superficial and deep pineal components of the intact hamster contain a rich network of green to yellow-green fluorescent nerve fibres. After either superior cervical ganglionectomy or after transection of the nervi conarii the majority of the fluorescing fibres disappeared from both the superficial and deep pineal masses. Although the deep pineal remained intact after surgical removal of the superficial pineal, it was devoid of any green or yellow-green fluorescent fibres.

Animals↗
PubMedDate not supplied

Clinical comparison of two contrast agents for oral cholecystography: radiologic efficacy and drug safety of iopanoic acid and iopronic acid.

Oral doses of either iopronic acid (4.5 g Oravue, Squibb) or iopanoic acid (3 g Telepaque, Winthrop) were given to 98 patients requiring cholecystography. Radiographs were taken 13 to 16 hours after treatment showed good to excellent gallbladder opacification in 44 percent of patients after the first dose of iopronic acid and in an additional 29 percent after a second dose. Similar opacification occurred in 42 percent of patients after the first dose of iopanoic acid and in 34 percent after a second dose. Drug-related abnormalities in blood and urine tests occurred about equally in both groups and one patient in each group exhibited a clinically adverse reaction (diarrhea). Thus, the performance (radiographic efficacy and drug safety) of the new contrast agent, iopronic acid, was similar to a widely used drug, iopanoic acid.

Administration, Oral↗