Search PubMed⌕ Search

Biomedical subjects

M Jakubowski

Publications and source records attributed to M Jakubowski.

At least 73 records · Page 4Linked to original sources
PubMed1985

Transition from pup killing to parental behavior in male and virgin female albino rats.

In the first part of this study, the effect of habituation to pups was examined in virgin female and male Sprague-Dawley rats that committed infanticide in a screening test. With repeated exposure to test pups (5-10 days old), the rats ceased to commit infanticide and came to behave parentally. Preexposure to inaccessible pups (confined inside wire-mesh baskets) did not accelerate the rate of disappearance of infanticide during subsequent contact with young, which suggests that pup killing is not a neophobic response to the novelty of young. In the second part of the study, three groups of infanticidal male Wistar rats were mated and tested for their responses towards unrelated pups after different intervals of cohabitation with their mates. The males continued to commit infanticide at the time that their mates were at midpregnancy or 24 hr before parturition, but males that cohabited with their mates till day 9 postpartum no longer attacked the young. Thus, the mother rat, presumably by means of postpartum aggression, renders her mate noninfanticidal, thereby reducing the likelihood of her offspring being harmed when she is away from the nest.

Aggression↗
PubMed1985

Role of nipple stimulation in the suppression of estrous cyclicity during extended lactation in the rat.

The role of nipple stimulation in the suppression of the estrous cycle during extended lactation was studied in rats subjected to either total, partial, or sham excision of the nipples. Each female cohabited with 4 pups, 4-14 days old, over a period of 70 days postpartum, during which vaginal smears were recorded daily. Initially, regardless of the presence of nipples, all rats exhibited a postpartum diestrus that lasted for 12-20 days. Intact females (bearing 6 pairs of nipples) continued to exhibit successive prolonged diestrous phases over 70 days of lactation. A comparable result was obtained with females bearing only the anterior pair of nipples, which, in a separate experiment, was found to be the most frequently suckled pair. However, females devoid of nipples resumed regular (4-day) estrous cycles between Days 12 and 27 postpartum, in spite of their continuous contact with pups. Thus, when lactation is prolonged beyond the normal time of weaning (Day 21 postpartum), stimulation of the nipples by sucking becomes indispensable for the continued arrest of the estrous cycle. The possible mechanisms underlying this phenomenon are discussed.

Animals↗
PubMed1985

Determination of diethyllead in the urine by flameless atomic absorption spectrometry.

A method for the determination of diethyllead in urine by flameless atomic absorption spectrometry after chelation with glyoxal-bis (2-hydroxyanil) and extraction of the formed complex with methyl isobutyl ketone is described. The method is specific in relation to both triethyllead and inorganic lead. The limit of detection was 3.2 micrograms Pb/l and the relative standard deviation in the concentration range 20-100 micrograms Pb/l was 0.076.

Adult↗
PubMed1985

Incidence of pup killing and parental behavior in virgin female and male rats (Rattus norvegicus): differences between Wistar and Sprague-Dawley stocks.

The responses toward young shown by males and nulliparous females differed substantially between two outbred stocks of laboratory rats. Sprague-Dawley females showed maternal behavior either spontaneously (35% of the naive rats) or through concaveation (92% of the initially neutral virgins). Of the Wistar females, however, only 10% showed maternal behavior spontaneously, and only 29% of the neutral virgins came to behave maternally during 15 days of concaveation. Prepubertal cohabitation with lactating rats did not facilitate maternal responsiveness in adulthood in the Wistar virgin females. Of the Sprague-Dawley males, 50% showed paternal behavior spontaneously, and only 4% killed the young. Among the Wistar males, however, only 4% showed paternal behavior spontaneously, and 76% killed pups. Such profound differences between outbred stocks of rats may be a source of discrepancies between the results of studies dealing with the induction of parental behavior in nonlactating rats.

Aggression↗
PubMed1985

[Health effects of occupational exposure to cadmium and its compounds and proposed preventive measures].

The paper presents effects of cadmium compounds upon human organism. Special attention was paid to disturbances resulting from chronic occupational exposure to those compounds. In addition, the description of toxic effects was supplemented with suggestions to carry on pre-employment and periodic examinations that would enable undertaking appropriate preventive measures for the population occupationally exposed to cadmium compounds.

Cadmium↗
PubMed1984

[Toxicokinetics of benzene in humans. Excretion of phenol with urine and benzene with expired air after single and 4-day inhalation exposure].

Five male volunteers were exposed to benzene vapour (100 mg X m-3) during 2 h singly and during 4 successive days. The mean retention of benzene in the lungs and mean dose amounted to 61% and 74 mg, respectively. Two phases of the excretion of unchanged benzene in the expired air (t 1/2 approximately 2 h and approximately 20 h) and phenol in the urine (t 1/2 approximately 3 h and approximately 12 h) were observed. The observed half time values were similar after single and repeated exposure. Respective values for 4-days experiment amounted to 28 and 47% of the dose absorbed during the last day of exposure. Concentrations of benzene in the expired air and the rate of excretion of phenol in urine were higher after 4-days exposure than after single exposure, which results from benzene toxicokinetics. Coefficients of kinetic processes rate amounted to k2 = 0,15; k3 = 0,07; k4 = 0,06 and sigma kEM = 0,16 X h-1.

Adult↗
PubMed1983

New details of the ultrastructure (TEM, SEM) of taste buds in fishes.

Quantitative distribution of the taste buds (TB) in different parts of the body and the fine structure of the TB components are described in Cobitis taenia L. No evidence of synaptic contacts between any cellular components in the TB has been found. The afferent synapses have been recognized only at the gustatory cells and at the basal cell. The microvillar processes on the upper side of the basal cell are demonstrated for the first time in fishes. These processes resemble those at the basal cells in the TB of tetrapods and at the Merkel cells, scattered in the epidermis of all vertebrates. Since the basal cells of fish TB correspond also to other criteria of the Merkel cells, its mechanoreceptive function in the TB is discussed. A relatively large number of atypical gustatory cells has been found in the studied material. As the examined specimens of C. taenia lived for a long time in aquarium conditions, it may be supposed that these gustatory cells are damaged by pollutants introduced mainly with food such as Tubifex. For purposes of comparison, a related species, Misgurnus fossilis L., was used in the study.

Animals↗
PubMed1982

Dimensions of respiratory surfaces of the gills and skin in the Antarctic white-blooded fish, Chaenocephalus aceratus Lönnberg (Chaenichthyidae).

Gill arches of C. aceratus are long and bear a small number of filaments (9...11/cm). Density of secondary lamellae on filaments decreases from 19.4/mm to 17.8/mm in the specimen examined (815...1820 g). In contrast to that, surface area of an average secondary lamella increases in larger specimens and is from 0.489 mm2 to 0.664 mm2, respectively. The total surface area of secondary lamellae per 1 g of body weight is from about 193 to 159 mm2. The skin vascularization of C. aceratus is abundant. The average length of subepidermal capillaries per 1 mm2 of skin is 28.4, their surface area is about 1.3 mm2. The length of subepidermal capillaries per 1 g of body weight varies from 4,121 mm in 815 specimen to 2,695 mm in 1,820 g specimen; their surface area is about 184 mm2 and 120 mm2, respectively. The obtained results prove that the respiratory surface area of the gills in C. aceratus is as large as that of red-blooded fresh-water fishes of a moderate activity. The rich skin vascularization and a most advantageous ratio of body surface area to body weight indicate great possibilities of the skin in the exchange of respiratory gases.

Animals↗
PubMed1981

Ultrastructure (SEM, TEM) of the olfactory epithelium in the wels, Siluris glanis L. (Siluridae, Pisces).

The number of lamellae in a single olfactory rosette of the Silurus increases with age. In one-year-old specimens there are about 50 lamellae, while in the three-year-old ones their number rises to 109. The surface area of an average lamella increases from 2.5 mm2 to 8 mm2, respectively. Four continuous zones have been distinguished in the olfactory epithelium that covers the lamella: olfactory sensory, ciliary, glandular and marginal. These zones differ with respect to their cellular composition. The olfactory zone occupies 25...30% of the total surface of the epithelium. Receptor cells occur exclusively in this zone. Two types of olfactory receptor cells have been distinguished, flagellar and microvillous. Special attention is given to a third type of receptor cell (perhaps nonolfactory) the so called compound cilium receptor. Striated rootlets do not occur near the basal bodies in the flagellar olfactory receptor cells but they are found in the compound cilium ones. It is believed that the compound cilium receptor cell is sensitive to water flow between the lamellae. The formation of the sensory terminals on the olfactory receptor cells is totally completed in Silurus not earlier than between the first and second year of age. Both, sensory flagellum and compound cilium type of terminals appear earlier than the sensory microvilli. It is believed that the described types of the receptor cells are quite independent ones.

Aging↗
PubMed1980

Induction by young of prolonged dioestrus in virgin rats behaving maternally.

The present investigation examined, by study of daily vaginal smears, whether the interaction of virgin female rats with young affected the oestrous cycle. Virgins behaving non-maternally or maternally were continuously exposed to young for extended periods. (1) All non-maternal virgins continued to cycle while 87% of maternal virgins ceased to cycle when exposed to young, and entered a series of prolonged dioestrous phases, each lasting about 14 days. Likewise, all maternal parous non-lactating controls exposed to young entered prolonged dioestrus. (2) The dioestrous phase induced by young in virgins was characterized by the decidual response. (3) Young aged 4-9 days were as effective as 10-15-day-old young for inducing and maintaining the dioestrus. (4) Confinement of young in a wire-mesh basket showed that body contact with young was essential to establish dioestrus. (5) Body contact with young was sufficient to induce dioestrus in maternal virgins with excised nipples. (6) Once established, the dioestrus could be maintained for about 12 days after removal of young as early as Day 4 of dioestrus in virgin and parous non-lactating females, but removal of young on Day 6 from post-partum lactating females resulted in a rapid resumption of cyclicity. (7) Prolonged suckling during a series of dioestrous phases induced lactation in 61% of maternal virgins, as well as in all parous control females.

Age Factors↗
PubMed1980

[Changes in blood biochemical parameters during physical exercise and recovery after prior diazepam administration].

The study involved 51 healthy males aged 20 -- 24, divided into two groups. Group I (30 subjects) performed exercise on a cycle ergometer with the load increasing according to the following schedule: 1 W/kg for six minutes, 2 W/kg -- six minutes, and 3 W/kg -- six minutes. The remaining 21 subjects (group II) performed identical exercise one hour after they had been administered 10 mg of diazepam (Relanium-Polfa). The determinations made included arterial blood levels of FFA, triglyceride, and glucose before the exercise, after each successive phase of the exercise, and in the course of restitution (30 minutes and 4 hours after the exercise). One hour after diazepam administration, the FFA, triglyceride and glucose levels decreased. After the successive phases of the exercise, the FFA levels were significantly lower among group II subjects, and continued to be so also in the 30th minute after the exercise. The decrease in the triglyceride levels during the exercise was higher among the diazepam subjects, and they were slightly lower also in the course of restitution. In both groups the glucose levels gradually increased after each phase of the exercise, and the increase after the third phase was higher among the diazepam subjects. During restitution the glucose concentration was higher than before the exercise, and slightly higher in group II.

Adult↗
PubMed1979

[Determination of phenol in the urine by means of gas chromatography].

A simple method of determination of phenol in urine was presented. The conditions of phenol combinations hydrolysis and extraction were the same as those used by Buchet (10). 2,4-dichlorophenol was used as an internal standard. The accuracy of this method for phenol concentrations in urine from 25 to 200 mg/l is +/- 8,2%. This method is specific both for the compounds excreted with physiological urine and the metabolites used in the industry of organic solvents.

Chromatography, Gas↗
PubMed1979

Anatomy and morphometry of the olfactory organ of the wels Silurus glanis L. (Siluridae, Pisces).

The anatomical structure of the olfactory organs, nerve tracts and brain was described in Silurus glanis. The changes connected with aging were considered. The olfactory lamellae are thin and tightly set in a rosette. In the 1 year old individuals there are 48...51 lamellae in a single rosette. This number increases gradually with age and in the 9...10 year old welses reaches 150. The surface area of the lamellae of a single rosette also indicates an increase: in the 1 year old specimen it equals 117 mm2, while in the adult individual (5...6 year old)--1040 mm2. This is due to the increase in both the size of each lamella and the number of the lamellae. The obtained results are discussed with regard to other author's data. It has been found that the dynamics of the increase of the surface area of the olfactory epithelium in fish are closely related to the way of life and not to the systematic affiliation of the species.

Aging↗