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Biomedical subjects

M Mikulajová

Publications and source records attributed to M Mikulajová.

18 recordsLinked to original sources
PubMed1998

Mannitol derivate used as a marker for voltammetrically monitored transport across the blood-brain barrier under condition of locus coeruleus stimulation.

1-Deoxy-1-nitro-D-mannitol (DN-Man) was used (femoral vein injection, approximate concentration in the blood 30 mmol.l-1) in pentobarbital anaesthetized rats as a promising marker detectable by differential pulse voltammetry (DPV) to study its transport across the blood-brain barrier (BBB) to the extra-cellular space of the frontoparietal cortex. DN-Man detection limit in in vitro calibrations (saline, blood) using DPV and carbon fiber microelectrodes was 0.5 mmol.l-1 with a good linearity (r = = 0.996) over the entire tested range (up to 30 mmol.l-1). The slow time-course of the rise of DN-Man signal (y = 106/(1 + (17.8/t)3)) in the cortex confirmed the functional BBB state. Electrical stimulation of the locus coeruleus (LC) (300 rectangular pulses at a frequency of 100 Hz, 1 mA, pulse duration 0.2 ms) elevated significantly DN-Man current in the cortex (to 168 +/- 59% of the control, mean +/- S.D., n = 8). The evoked permeation increase of the BBB to DN-Man was short-lasting (minutes), and the second LC stimulation (repeated 5 min after the first one) was ineffective. This fact was probably due to the reduction of DN-Man levels in blood and/or an altered response of microvessels to neurotransmitters. It was shown here that, under carefully controlled surgical and experimental conditions, DPV and DN-Man might be useful for the monitoring of the regional dynamics of BBB transport changes. The presented results also support the view that BBB transport can be influenced by LC neuronal activity.

Animals↗
PubMed1989

[Vacuolated neurons in the superior cervical ganglion in rats after repeated stress].

In the article the authors deal with unsolved problem of the occurrence and character of vacuolated neurons (VN) in autonomic ganglia. They describe their own investigations of vacuolated neurons in the superior cervical ganglion of male rat (Wistar) after repeated stress and fixation of the tissue in glutaraldehyde/OsO4. Vacuolated neurons had a well-preserved structure of ganglion cell in spite of that in cytoplasma they contain vacuoles reaching enormous size. Vacuoles had very characteristic content. They were filled in by content of thin density. Along the membrane of the vacuole were cytoplasmatic extensions, their transverse profiles and isolated invaginations of the membrane of vacuole. From the structure of the vacuole cannot be appreciated the character of the vacuole--whether it is phagosomes or the reservoir of cell metabolite established for its function. Because the vacuolated neurons have the same structure as vacuolated neurons in autonomic pelvic ganglia of the rat, the authors in discussion dealt especially with the results of the investigation of the mentioned ganglia.

Animals↗
PubMed1976

Adaptation of pancreatic amylase activity to enhanced parenteral carbohydrate intake in rats, and electron microscopic findings.

The present study records a rise of amylase activity in rat pancreatic tissue after a long-term administration of high carbohydrate diets (14% excess of glucose administered orally or subcutaneously as 30% glucose solution) in comparison to a normal diet. It was concluded that the pancreas obtains information on intestinal food composition along the humoral pathway. Electron microscopic investigations revealed no impairment of the acinar cells of the pancreas, but only changes that may be considered as a structural expression of the various phases of activity of the acinar cells.

Adaptation, Physiological↗