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Biomedical subjects

M Jakubowski

Publications and source records attributed to M Jakubowski.

At least 55 records · Page 3Linked to original sources
PubMed1991

[A latex immunologic method of analysis of low-molecular proteins and albumin in urine. II. Beta 2-microglobulin, retinol-binding protein and albumin levels in the urine of general Polish population and workers exposed to cadmium].

The aim of the work was to collect data about beta 2-microglobulin (beta 2M), retinol-binding protein (RBP) and albumin (Alb) levels in subjects not exposed to nephrotoxic agents in Poland. The data are necessary to interpret determination results in persons occupationally exposed to these chemicals. Concentrations of beta 2-microglobulin, retinol-binding protein and albumin in urine were determined using latex-immunological method. Examination of levels of low molecular proteins and albumin was made on population from agricultural regions of Poland (the Suwałki region) and on textile plant workers from Lódź not exposed to nephrotoxic agents. It was found that upper normal level of low molecular proteins in urine was 300 micrograms/l and of albumin 60 mg/l. The data obtained indicate that sex and age play an important role in beta 2-M and RBP excretion. In the workers of an alkaline accumulator plant who were occupationally exposed to cadmium, a statistically increased excretion of low molecular proteins in urine was observed compared to the controls from Lódź. In 20% of the subjects beta 2-M and RBP concentration in urine were higher than the accepted upper normal levels. Collected data make one aware of necessity to study the above determinations which lead to an early detection of renal function disorders.

Age Factors↗
PubMed1991

[Latex immunologic methods of determining micro-molecular proteins and albumins in urine. Part I. Description of the method].

The most frequent markers of early kidney dysfunction include determination of micromolecular proteins, such as beta 2-microglobulin (beta 2M), retinol-binding protein (RBP) and albumins (Alb), in urine. The determination of those proteins in urine is carried out by means of immunological methods. The latex-immunological methods (LIA), allowing to avoid the use of radioisotopes and relatively cheap one as compared with ready-made proprietary kits, may prove to be particularly useful in Polish laboratories. The LIA method in routine tests of protein content in urine was practically assessed. Reproducibility of the method was verified under the conditions of international quality control.

Albuminuria↗
PubMed1990

The relationship between exposure monitoring and health status in the occupational setting. An information system on exposure levels and occupational diseases.

The relationship between the level of occupational exposure to different noxious factors and the health consequences of these in exposed populations is discussed using cadmium, lead, carbon disulphide and vinyl chloride as examples of occupational pollutants. The legal status and organizational system of monitoring the exposure to occupational pollutants and health effects in Poland are presented. The scope and sources of data on the occupational exposure level as well as the register of occupational diseases are evaluated.

Air Pollutants, Occupational↗
PubMed1990

Neurobehavioral effects of experimental exposure to toluene, xylene and their mixture.

The effects of experimental exposure to toluene (100 ppm), xylene (100 ppm) and their mixture (50 ppm of toluene and 50 ppm of xylene) on CNS functions were studied in 10 male volunteers aged 22-35. Changes in CNS functions were measured by means of nine psychological tests. Acute exposure to xylene produced the most adverse effect on simple reaction time SRT and choice reaction time ChRT. Exposure to toluene affected only the memory test performance. The effect of combined exposure appeared to be weaker than the effect of exposure to xylene alone but stronger than the effect of exposure to toluene.

Adult↗
PubMed1989

Estradiol stimulates preoptic area-anterior hypothalamic proGnRH-GAP gene expression in ovariectomized rats.

The decapeptide gonadotropin-releasing hormone (GnRH) and the 56-amino acid GnRH-associated peptide (GAP) are derived from a common precursor translated from the proGnRH-GAP mRNA. Studies using solid-phase hybridization techniques (i.e., Northern blot analysis, dot blot analysis, or in situ hybridization autoradiography) have yielded a controversy as to whether estradiol stimulates, inhibits, or has any effect on proGnRH-GAP gene expression in the preoptic area-anterior hypothalamus (POA-AH) of the ovariectomized (OVX) rat. Using a sensitive and quantitative solution hybridization-nuclease protection assay, which ensures complete hybridization of target RNA to probe RNA, we examined the effects of OVX and estradiol replacement on the amount of proGnRH-GAP mRNA in individual POA-AH dissections. Rats sacrificed at different intervals after OVX showed a significant time-dependent decrease (34-60%) in the levels of POA-AH proGnRH-GAP mRNA relative to sham-operated animals; OVX rats treated with estradiol, however, had proGnRH-GAP mRNA levels comparable to those of sham-OVX animals. To verify these observations, levels of the proGnRH-GAP peptide, measured by radioimmunoassay with antibodies directed against the cleavage and amidation site between the GnRH and the GAP portions fo the precursor molecular, were also found to decrease (37%) after OVX and increase (63-85%) following estradiol replacement, relative to intact rats. These data support the view that estradiol stimulates the levels of both proGnRH-GAP mRNA and its primary translation product in the POA-AH region of the OVX rat.

Animals↗
PubMed1989

Excretion of methylbenzoic acid in urine as a result of single and combined exposure to m-xylene.

Influence of combined exposure to solvent vapours on the metabolism of m-xylene and the kinetics of excretion of methylbenzoic acid (MBA) in urine was investigated. The volunteers were exposed in groups of four or five. Each experiment consisted of two parts. During the first part, the same test group was exposed to m-xylene for a period of 4 hours, whereas during the second part, the group was exposed to m-xylene in combination with other solvents. No significant differences in the excretion of MBA in urine were observed after exposure to m-xylene in concentrations of about 45 and 70 ppm and exposure to m-xylene together with n-hexane, toluene, methyl isobutyl ketone or n-butyl alcohol in combined concentrations of about 90 and 140 ppm. Only in the case of combined exposure to m-xylene and n-butyl acetate was a significant increase in the excretion of MBA in urine found. For both the single and combined exposure to kinetics of excretion of MBA was similar with t1/2 values in the first phase of excretion ranging between 1-1.3 h.

Acetates↗
PubMed1988

The spectrum of closed-head injuries in facial trauma victims: incidence and impact.

Little is known of the incidence of closed-head injury (CHI) associated with facial trauma. To study this problem, we conducted a retrospective review of 200 consecutive admissions to the University of Michigan Medical Center Emergency Department from 1980 to 1985 for treatment of acute facial fractures. All patients were admitted within 48 hours of injury (93% within 24 hours). Medical records were reviewed for age, sex, description, and circumstances of facial injury; assessment of loss of consciousness and anterograde amnesia; and associated intracranial or extracranial injuries. Seventy-three percent of the patients were men (mean age, 27.8 years). Etiologies, in descending order, were road traffic accidents (52%), assaults (22%), sports (14%), falls (7%), other injuries (3%), and gunshot wounds (2%). The incidence rate of CHI in our study was 55%. More than 90% of the head injuries were associated with the loss of consciousness of less than one hour. Risk factor analysis failed to demonstrate that an increased risk of CHI is associated with age, sex, or number of facial fractures. However, there was a one and one-halffold increased risk associated with patients involved in automobile accidents.

Accidents, Traffic↗
PubMed1988

Preoptic-hypothalamic pathways controlling nocturnal prolactin surges, pseudopregnancy, and estrous cyclicity in the rat.

Frontal, dorsal, or sham deafferentations were placed at various locations within the hypothalamus in order to study the neural pathways involved in pseudopregnancy (PSP), estrous cyclicity, and prolactin (PRL) secretion in the rat. Dorsal or sham transections did not interfere with PSP or estrous cyclicity. Frontal cuts placed on day 3-4 of PSP between the posterior border of the optic chiasm and the anterior tip of the mediobasal hypothalamus (MBH) led to interruption of diestrus within 3-5 days. With frontal cuts placed more caudally in the MBH, and with frontal cuts placed rostrally at the anterochiasmatic area, the duration of PSP was within normal range. Irrespective of their effects on PSP, anterochiasmatic and retrochiasmatic cuts were associated with onset of persistent estrus, and MBH transections resulted in either persistent estrus in some rats or regular estrous cycles in the others. In deafferentated rats that showed persistent estrus, the basal plasma concentrations of PRL measured 3-4 weeks after ovariectomy were 2- to 3-fold higher than in deafferentated and sham-deafferentated animals that were cyclic before ovariectomy. Electrical vaginocervical stimulation induced secretion of nocturnal PRL surges in long-term ovariectomized rats with dorsal or sham transections, but not in those bearing frontal cuts, regardless of the neuroanatomical location of the frontal cut. These results suggest that (1) impulses generated at the uterine cervix must reach the medial preoptic area, a putative 'anti-surge center', and proceed from there to the MBH, in order to allow initiation of nocturnal PRL release.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Occupational exposure to cadmium and kidney dysfunction.

Investigations were carried out in an alkaline battery factory. The study group consisted of 102 persons and the control group of 85 persons. Cadmium in blood (Cd-B) and cadmium in urine (Cd-U), as well as beta 2-microglobulin (B2-M), retinol binding protein (RBP), amino acids in urine were determined. Exposure to cadmium was high; Cd-B and Cd-U concentrations were higher than recommended, 10 micrograms/l and 10 micrograms/g creat. In 65% and 56% of workers, respectively. Excretion of B2-M and RBP in urine was higher than the accepted upper limits of 380 and 130 micrograms/g creat. in about 20% of the workers. A significant correlation was observed between: log Cd-U.log Cd-B (r = 0.85), log B2-M.log RBP (r = 0.66), log Cd-U.log B2-M (r = 0.52), and log Cd-U.log RBP (r = 0.55). To evaluate the admissible period of occupational exposure to cadmium, an integrated exposure index (Cd-B x years of exposure) is proposed. According to the dose-response relationship, an increase of low molecular protein excretion in urine can be expected in 10% of the cases at Cd-U amounting to 10 to 15 micrograms/g creat. and Cd-B x years of about 300 to 400.

Adult↗
PubMed1987

2-Cyanoethylmercapturic acid (CEMA) in the urine as a possible indicator of exposure to acrylonitrile.

The aim of this study was to evaluate the efficiency of metabolism of acrylonitrile (ACN) to N-acetyl-S-(2-cyanoethyl)-L-cysteine (2-cyanoethylmercapturic acid (CEMA) in man, the kinetics of excretion of this metabolite, and the relation between the uptake of ACN and the excretion of CEMA in urine. Eleven experiments were performed on six male volunteers exposed for eight hours to ACN at concentrations of 5 or 10 mg/m3. The average respiratory retention of ACN was 52% and 21.8% of the retained ACN was excreted as CEMA in urine. Elimination approximated first order kinetics with half life of about eight hours. The best correlation between the uptake of ACN in the lungs and excretion of CEMA in urine was obtained when the concentration of CEMA in the urine fraction, collected between the sixth and eighth hours after the beginning of exposure, was adjusted to a specific gravity of 1.016 (y = 0.33x-13.3; r = 0.83). CEMA excretion, however, cannot be used as an individual index of exposure.

Acetylcysteine↗
PubMed1986

Nocturnal surges and reflexive release of prolactin in parentally behaving virgin female and male rats.

Maternally behaving virgin rats are capable of releasing prolactin reflexively in response to stimulation by pups, especially during the proestrous/estrous phase of the cycle. When such rats are chronically exposed to pups they usually undergo a state of pseudopregnancy during which prolactin is secreted in a pattern of nocturnal surges. The present series of experiments evaluated the initiation of nocturnal prolactin surges in maternally behaving virgins, the role of estrogen in the reflexive release of prolactin, and the influence of gender on these two modes of prolactin secretion. It was found that the nocturnal surges of prolactin are already present on Days 1 and 2 of pup-induced pseudopregnancy. At this stage, however, the surges are not yet autonomous, seeing that pseudopregnancy is interrupted shortly after removal of the pups on Day 2. Activation by vaginocervical stimulation of the "mnemonic" neurogenic system that controls the autonomous nocturnal prolactin surges did not interfere with the reflexive pup-induced release of prolactin in maternally behaving virgins. The capacity of reflexive prolactin release in the virgin rat was abolished by ovariectomy, restored by estrogen replacement, and persisted for only 24 hr following estrogen removal. Paternally behaving males subjected to chronic exposure to pups were incapable of secreting nocturnal surges of prolactin characteristic of the pseudopregnant female. Such males were also incapable of releasing prolactin reflexively in response to stimulation by pups, even when supplemented with exogenous estrogen. These results indicate that the two modes of prolactin secretion are sex dependent, and that the maternally behaving virgin, unlike the postpartum rat, requires concurrent estrogenic facilitation for releasing prolactin in response to stimulation by young.

Animals↗
PubMed1986

Lactational performance, consummatory behavior, and suppression of estrous cyclicity in rats suckling underfed pups.

The role of pups' appetite in the regulation of maternal consummatory behavior (food intake of nursing mothers), lactational performance and postpartum diestrus was studied over a period of 45 days postpartum in rats chronically exposed to either underfed or normally fed pups. Experimental rats (n = 10) daily received 5 pups, 4-10-days-old, that had been deprived of food for the preceding 24 h while under the care of nonlactating foster mothers. Control rats (n = 10) received normally fed pups obtained daily from lactating foster mothers. Throughout the experimental period, the daily milk yield (estimated by litter weight gain), the intake of food and water by the mother, as well as the ratio of litter weight gain to mother's intake of food and water were all markedly higher in rats nursing underfed pups than in rats nursing normally fed pups. After a peak in lactation around Day 15 postpartum, experimental rats produced the same amount of milk during extended lactation as they did in the beginning of lactation, while control rats produced only half the amount of milk during extended lactation as they did in early lactation. Regardless of the nutritional state of the suckling pups, maternal body weight increased progressively over the first four weeks of lactation and remained unchanged during the time of extended lactation. The postpartum diestrus and the subsequent diestrous phase in the time of extended lactation were considerably longer in duration in rats that nursed underfed pups. On Day 45 of lactation, prolactin levels were higher and the adrenal glands were larger in experimental rats than in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Female reproductive function and sexually dimorphic prolactin secretion in rats with lesions in the medial preoptic-anterior hypothalamic continuum.

The role played by the medial preoptic area-anterior hypothalamus (MPOA-AH) in the regulation of reproductive function of the female rat was examined in the first part of the present study. Extensive bilateral lesions placed in different locations of the MPOA-AH continuum resulted in three different patterns of vaginal smears. Lesions located most rostrally and dorsally, sparing the suprachiasmatic nuclei (SCN), resulted in series of successive pseudopregnancies. Lesions located more caudally and ventrally, still sparing the SCN, eventuated in regular oestrus cycles with only occasional pseudopregnancies. MPOA-AH lesions encroaching upon the SCN were associated with persistent vaginal cornification. MPOA-AH-lesioned females exhibiting repeated pseudopregnancies were capable of mating, conceiving, and giving birth. Parturition in these females was uniformly delayed by 1 day and was associated with a variable incidence of stillbirth, cannibalism of newborn, or incomplete placentophagy. As a rule, MPOA-lesioned mothers did not retrieve pups but they did show crouching behaviour and some of them even secreted milk. Thus, while the MPOA subserves in the regulation of oestrous cyclicity and maternal behaviour, it appears to play no essential role in mating behaviour or in ovarian function during pregnancy and lactation. The pattern of prolactin secretion in MPOA-AH-lesioned male and female rats was evaluated in the second part of this study. Both intact and orchidectomized males were incapable of generating nocturnal prolactin surges following extensive bilateral ablation of the MPOA-AH. On the other hand, 6 out of 9 ovariectomized MPOA-AH-lesioned females exhibited spontaneous nightly surges of prolactin. The absence of the surges in the remaining 3 females was associated with invasion of the lesion into the SCN and/or structures rostral to the MPOA. During the light period, prolactin levels remained within the basal range in all lesioned females, irrespective of the presence or the absence of the nocturnal surge. These lesioned ovariectomized females, in contrast to nonlesioned females, were incapable of producing a diurnal (afternoon) surge of prolactin in response to administration of oestrogen, though their basal prolactin levels were much higher than the levels seen in oestrogen-treated, nonlesioned castrated males. These results support the view that the MPOA is inhibitory to the nocturnal prolactin surge while stimulatory to the diurnal surge. The results also suggest that the male rat is functionally devoid of both a 'diurnal-surge centre' residing in the MPOA, and a 'nocturnal-surge centre' located outside the MPOA.

Animals↗
PubMed1986

Prolactin release and milk ejection in rats suckling underfed pups.

Mother rats chronically exposed to underfed pups (obtained daily from nonlactating mothers) show increased milk production which is associated with increased consumption of food and water. The purpose of the present study was 2-fold: to examine whether the magnitude of maternal PRL discharge is related to the nutritional state of the pups and to differentiate between the role of the mother and that of the pups themselves in the regulation of milk intake. PRL release in response to reunion with pups (preceded by 4-h separation from pups) was measured between days 12 and 14 postpartum; each mother was tested twice, once with hungry pups (deprived of food for 24 h) and once with satiated (normally fed) pups. The magnitude of PRL discharge elicited by hungry pups in lactating as well as in thelectomized rats was twice as large as the discharge elicited by satiated pups. For each type of stimulus pups, the magnitude of PRL release was smallest in thelectomized rats, largest in rats that had nursed normally fed pups before testing, and intermediate in rats that had nursed underfed pups. The frequency of milk ejection was considerably reduced in mothers that were chronically exposed to underfed pups compared with mothers that had nursed normally fed pups. Regardless of the mother's previous history, and independent of the milk ejection frequency or maternal food and water intake, hungry pups ingested more milk than did satiated pups over the same suckling period even when both types of pups were suckled simultaneously by the same female. Milk ingestion in satiated pups was not enhanced by the vigorous sucking exerted by hungry littermates. It is suggested that hungry pups are able to meet their increased nutritional demands both directly, by withdrawing a larger portion of the milk available in the mammary glands, and indirectly, by enhancing maternal PRL secretion which in turn may promote maternal consummatory behavior and milk production.

Animal Population Groups↗
PubMed1986

Results and perspectives of collaboration of CMEA member countries in the field of developing sanitary-chemical methods of determining toxic compounds in the air and biomedia.

Some theoretical and practical problems of controlling industrial environment and biological substrates in the CMEA countries are discussed. Particular attention has been paid to the unification of methodological instructions concerning common requirements and methods of supervision, as also to the coordination and unification of the methods of determining some chemical compounds in the air of the working zone and in biological materials.

Air Pollutants, Occupational↗
PubMed1985

Anaesthesia for microsurgery.

The data from a retrospective study of 32 anaesthetics administered for free-flap tissue operations are analysed. We suggest balanced analgesic-dominated general anaesthesia, supported wherever possible by continuous regional block. Special attention is paid to full control over the cardiovascular system and the haemodynamics, including the microcirculation and optimal rheological properties of the blood, as well as metabolic ability. Our results suggest that factors such as adequate infusion therapy guided by central venous pressure and urinary output and strict body temperature control, supplementary use of regional blocks and peri-operative use of dextran 40 (Rheomacrodex) can contribute significantly towards the overall success of free-flap surgery.

Adolescent↗