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Biomedical subjects

F Ellendorff

Publications and source records attributed to F Ellendorff.

At least 91 records · Page 5Linked to original sources
PubMed1977

Uterine position and presentation of minipig-fetuses and their order and presentation at birth.

Uterine position and presentation of fetuses in 17 minipigs during pregnancy were compared with their order and presentation at birth. Fetuses from 1 or both uterine horns were marked between day 80 and day 105 of gestation by 1 or more transuterine injections of either a 2.5% solution of dianil blue (3 animals) or a radiopaque substance (14 animals). Roentgenograms of the newborn pigs, which were ear-notched immediately after birth, enabled making individual identification. Pigs seemed to be delivered randomly from the 2 uterine horns. They either followed a neighbor from the same horn (n = 42) or followed a pig from the contralateral horn (n = 52). Only in 3 dams did 1 uterine horn become empty before delivery from the other horn started. In 4 dams, 1 pig passed its neighbor from the same horn, thereby being born earlier than expected. Moreover, passing of pigs could have occurred and gone undetected in those dams from which the pigs of only 1 horn were marked. This passing might have taken place within the uterine body. From 18 of 95 pigs (19%) , the presentation at birth differed from the one observed at laparotomy.

Animals↗
PubMed1976

Non-random distribution of cell types in the preoptic and anterior hypothalamic areas.

1. Single units were recorded extracellularly from the preoptic and anterior hypothalamic areas of male and female rats anaesthetized with urethane. 2. The effect of single shock stimulation of both the mediobasal hypothalamus and corticomedial amygdala upon unit activity was assessed for all cells. Neurones were designated either antidromically invaded, orthodromically excited or inhibited, or non-responsive. 3. The distribution of responses among recorded cells was analysed for two groups of neurones. In one group the intercell distance was less than 100 mum and in the second group the distance was more than 1 mm. 4. For widely separated cells the connexions with the corticomedial amygdala and mediobasal hypothalamus were distributed at random. 5. In the groups of cells clustered closely together a marked structuring of connexions was apparant. In particular, there was a significant correlation between orthodromic responses from the amygdala (P less than 0-05) and cells antidromically activated and orthodromically excited by stimulation of the mediobasal hypothalamus were frequently adjacent to one another (P less than 0-02. 6. A complimentary analysis demonstrated that cells in the ventral half of the recording zone received significantly more inhibitory inputs from both the mediobasal hypothalamus (P less than 0-001) and the corticomedial amygdala (P less than 0-02) than those situated more dorsally. 7. The data provide evidence for structuring and orderliness in hypothalamic connexions that is often not apparent from descriptions of electrophysiological experiments.

Amygdala↗
PubMed1976

Plasma luteinizing hormone and progesterone in the adult female pig during the oestrous cycles, late pregnancy and lactation, and after ovariectomy and pentobarbitone treatment.

In a series of experiments on female miniature pigs, the pattern of plasma LH and progesterone levels during the oestrous cycle, late pregnancy and lactation and after ovariectomy were characterized, and the effect of pentobarbitone treatment was tested. The preovulatory surge of LH occurred in seven out of eight animals between 00.00 and 12.0 h on day 0 of the oestrous cycle (day 1 of standing heat). Plasma progesterone strated to decline 8 days before oestrus and reached its lowest value 5 days before the preovulatory LH peak. Increases in progesteron concentration were already noticeable 48 h after the LH surge. During late pregnancy, parturition and lactation, plasma LH was low and showed only minor fluctuations, while plasma progesterone declined 4 to 5 days before parturition. Both hormones remained at low levels throughout lactation. Three weeks before parturition increases in LH were always followed by an increase in progesterone. This dependency was greatly diminished immediately before delivery. Four to 12 days after weaning the animals came into oestrus which was followed by an increase in LH and later an increase in progesterone concentrations. Ovariectomy during dioestrus resulted in a steady increase in plasma LH levels of 35-39 days. Ovariectomy caused abortion if performed on day 100 of pregnancy. It was followed by a rapid increase of plasma LH concentration. Normal parturition (around day 115) and lactation took place when animals were spayed on day 112 of pregnancy. In this case, plasma LH levels remained even lower than before ovariectomy as long as lactation was maintained. Immediately after weaning a rapid increase in the normal postovariectomy pattern of LH secretion was observed. Pentobarbitone anaesthesia (30-35 mg/kg body wt, initial dose), during pro-oestrusoestrus, for less than 5 h had no effect on the preovulatory LH increase. However, pentobarbitone anaesthesia for more than 6 h inhibitied the LH peak and ovulation if the animal was under deep anaesthesia before 24.00 h on the day before oestrus. Pentobarbitone treatment of ovariectomized pigs resulted in a clear decrease in LH levels 40 min after a single i.v. dose.

Animals↗
PubMed1975

Response of medial preoptic neurons to electrical stimulation of the mediobasal hypothalamus, amygdala and mesencephalon in normal, serotonin or catecholamine deprived female rats.

Single cell activity from preoptic neurons was extracellularly recorded in normal female rats and the effects of electrical stimulation of the mediocortical amygdala (AMY), the N. med. raphes (MES) and the mediobasal hypothalamus (MBH) was tested. 1. One type of preoptic neurons (55%) reacted with primary excitation to a single electrical stimulus of AMY, MES or MBH, which was usually followed by a period of postexcitatory inhibition. Another type of neurons (29%) were first inhibited after stimulation of AMY, MES or MBH and then showed a period of postinhibitory excitation. The discharge rate of a third type was not affected by electrical stimulation of these structures (16%). If a neuron was affected by a stimulus in a given area it predictably reacted in the same fashion to stimulation of the other areas. 2. The postexcitatory inhibition of the majority of the primarily excited neurons was strong enough to prevent the stimulus response to a second stimulus. Occasional recordings from two neighboured cells simultaneously indicate that they can be inhibitory to each other. 3. By pulse train stimulation of the AMY or MES with varying frequencies it could be demonstrated that low frequencies (10 Hz) had a facilitatory action whereas higher frequencies (100 Hz) were inhibitory to preoptic discharge rates. 4. No obvious alteration of neuronal properties we found neither in rats treated intraventricularly with 5,6-dihydroxytryptamine, which strongly reduces central nervous system serotonin content, nor in 6-hydroxydopamine treated rats, which had low central nervous system catecholamine levels.

5,6-Dihydroxytryptamine↗
PubMed1975

Plasma luteinizing hormone and testosterone in the adult male pig: 24 hour fluctuations and the effect of copulation.

Secretory patterns of LH and testosterone were characterized in the intact male miniature pig. All blood samples were taken from indwelling catheters. Hourly sampling was carried out over 24 h and during a morning period blood was collected for 2 h at 10 min intervals. No significant difference was detected in the plasma LH concentration on the basis of hourly sampling. Plasma testosterone was significantly (P less than 0-05) lower during the evening and night when compared with morning values. The second experiment was concerned with the pattern of plasma LH and testosterone concentrations before and after copulation. Blood sampling was performed at 10 min intervals. Plasma LH was significantly (P less than 0-001) raised for 30 min after copulation when compared with any 30 min period (0-120 min) before copulation. Plasma testosterone was not significantly altered for any 30 min period of the experiment (0-270 min). The data are interpreted as a possible mechanism for endocrine control of testicular function.

Animals↗