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Biomedical subjects

R Nowak

Publications and source records attributed to R Nowak.

At least 163 records · Page 9Linked to original sources
PubMed1989

[Halothane anesthesia of several hours' duration in swine of the German Landrace breed, selected for resistance to malignant hyperthermia].

The malignant hyperthermia syndrome is widely spread in pigs of the German Landrace. This has precluded the use of halothane anesthesia. The advent of homozygous halothane-negative strains stimulated us to test whether such animals were suitable for longduration halothane anesthesia. Nine sows of the German Landrace (n = 4, homozygous halothane-positive (H+); n = 5, homozygous halothane-negative (-)) were used. Anesthesia was induced by Azaperon/Metomidat-HCL followed by intubation and exposure to halothane. All 4 halothane-positive animals died within 45-90 min following the onset of halothane administration, while all 5 halothane-negative animals survived a 4-5 h deep anesthesia without problems. Thus, homozygous hylothane-positive strains of German Landrace pigs may be surgically anesthetized for long durations with halothane anesthesia.

Anesthesia↗
PubMed1989

[The role of calcium homeostasis hormones in the development of tolerance following drug and alcohol consumption].

The present experiments were performed in order to assess the effects of cocaine and ethanol on the calcitonin and parathyroid hormone present in the cerebrospinal fluid and plasma of sheep in vivo. Cocaine or ethanol were i.a. administered daily up to 20 days to sheep. Blood and CSF were obtained simultaneously at 1 hour intervals. CSF and plasma CT and PTH were measured by radioimmunoassay. Blood alcohol concentrations were determined by GC. The results indicated that cocaine and ethanol administrations were followed by increase of both PTH and CT in plasma and CSF. However, this effects are present only up to 10 days. Later the concentrations of CT and PTH remained unchanged. This indicated the development of physical tolerance.

Alcoholism↗
PubMed1988

Deposition of cocaine in tissue after lethal and repeated sublethal administration to sheep.

The deposition of cocaine in tissue after lethal administration to sheep was investigated. In addition, the presence of cocaine in tissue obtained from sheep treated for 30 days with a sublethal dose (2.4 mg/kg b.wt.) after 1-day, 1-week, or 1-month withdrawal was studied. The determination of cocaine was performed by radioimmunoassay. The concentrations measured represent the sum of cocaine and its metabolites. The presence of cocaine was also qualitatively proven by gas chromatography/mass spectrometry. After a lethal dose administration cocaine was found in all investigated organs. The highest concentrations were present in liver, bile, and kidney. In tissue obtained from the sheep treated daily with a sublethal dose and killed after 1-week withdrawal, the concentrations found were significantly lower. After 1-month withdrawal, cocaine was not to be discovered in tissue.

Animals↗
PubMed1988

Immunolocalization of beta-lipotropin in the inner ear of the guinea pig.

The occurrence of beta-lipotropin (beta-LTH) immunoreactive material was investigated in the inner ear of newborn and juvenile guinea pigs by means of Sternberger's PAP technique. Unlike met5-enkephalin and endorphin, beta-LTH could not be found in the organ of Corti but was identified in the spiral ganglion and the neuroepithelium of the crista ampullaris.

Animals↗
PubMed1988

Ornithine decarboxylase in the inner ear of the guinea pig.

L-Ornithine decarboxylase, the rate limiting enzyme of polyamine synthesis and a possible marker enzyme for tissue proliferation and maturation, has been found in the developing guinea pig cochlea using the unlabelled horseradish-peroxidase-antiperoxidase technique. Ornithine decarboxylase-like immunoreactive material was detected in the neurons of the Ganglion spirale and in their axonal and/or dendritic fibers. The location of the enzyme and the possible functional role of ornithine decarboxylase plays in the development and maturation of the auditory organ and of the hearing process are discussed.

Aging↗
PubMed1988

Diurnal rhythms in plasma melatonin concentrations in the fetal sheep and pregnant ewe during late gestation.

We have measured plasma melatonin (MT) concentrations in the pregnant ewe and fetal sheep during 24-h periods between 114 and 142 days gestation. There was a clear diurnal rhythm in the plasma MT concentrations in both the ewe and fetus from 114 days gestation. Blood samples were also collected from the pregnant ewe and fetus during the day every 2-3 days from 112 days gestation to term. There was no gestational age trend in maternal or fetal day time plasma MT concentrations during late pregnancy. To establish whether there was transplacental transfer of MT, pregnant ewes were injected with [3H]MT, and total radioactivity (disintegrations per min) was measured in maternal and fetal arterial plasma and in amniotic fluid collected before and for 1 h after the [3H]MT injection. Two minutes after [3H]MT injection, radioactivity was detected in both maternal and fetal sheep plasma. Extraction of fetal plasma with chloroform indicated that [3H]MT accounted for 48.0 +/- 7.2 (SE) % of total radioactivity at 2 min after the injection. In one pregnant ewe infused with unlabeled MT (0.3 microgram/ml saline.min for 20 min) maternal and fetal plasma MT concentrations increased within 6 min after the start of the MT infusion. We conclude that there is a diurnal rhythm in the plasma concentrations of MT in the fetal lamb and pregnant ewe between 114 and 142 days gestation, and that MT crosses the ovine placenta from the maternal to the fetal circulation. Therefore, the MT present in the fetal sheep circulation may be solely of maternal origin or it may be derived from both fetal and maternal sources.

Animals↗
PubMed1988

[HLA antigens in patients with laryngeal cancer].

The HLA-ABC- and -DR-antigens of patients with carcinoma of the larynx were determined. The frequencies were compared with those of a normal population. No significant deviations in the antigen frequencies were observed in the distribution of HLA antigens. Therefore, participation of HLA-ABC and -DR gene products in pathogenesis of carcinoma of the larynx as an expression of a genetical component cannot be postulated till now.

Female↗
PubMed1987

Radioimmunological determination of cocaine in human hair.

A simple procedure for the determination of cocaine in human hair was described. After washing hair samples were crushed in 0.1 m HCl and incubated overnight at 45 degrees C. The acid extracts were neutralized with 1 m NaOH. Phosphate buffer (pH 7.4) was added to the extracts. The cocaine concentrations were measured by radioimmunoassay. Detection in hair was achieved in all hair samples obtained from cocaine users. This method appears to be suitable for the routine determination of cocaine.

Cocaine↗
PubMed1987

The correlation between serum and salivary melatonin concentrations and urinary 6-hydroxymelatonin sulphate excretion rates: two non-invasive techniques for monitoring human circadian rhythmicity.

Although there is a circadian rhythm in blood melatonin concentrations in humans, the problems associated with frequent blood collection limit the use of this rhythm in the investigation of the circadian system and in the diagnosis and treatment of chronobiological disorders. Therefore, to establish a convenient, non-invasive technique for monitoring melatonin circadian rhythmicity, we compared the melatonin concentrations in blood samples collected from five subjects every 2-4 h over a 26 h period, with the melatonin concentrations in saliva samples and with the total amount of 6-hydroxymelatonin sulphate excreted in the urine during 2-h periods. There was significant correlation between serum and salivary melatonin concentrations (r = 0.81, P less than 0.001), and between serum melatonin concentrations and 6-hydroxymelatonin sulphate excretion rates (r = 0.72, P less than 0.001). The results demonstrate that both salivary melatonin concentrations and urinary 6-hydroxymelatonin sulphate excretion rates are reliable indices of serum melatonin concentrations. These measurements, in combination with frequent sample collection, provide two convenient, non-invasive techniques for monitoring melatonin circadian rhythmicity.

Adult↗
PubMed1987

Length of melatonin exposure and onset of ovarian activity in anoestrous ewes.

Adult anoestrous ewes (N = 30) were given intravaginal Silastic implants containing melatonin or empty implants (N = 7) during mid-anoestrus (4 July). Implants were removed 16 days later (Group 1), 36 days later (Group 2) or 93 days later (Group 3). Blood samples were taken twice weekly for progesterone assay to monitor onset of ovarian activity. The percentage of ewes in each group showing early onset of ovarian cyclicity was significantly correlated with length of exposure to melatonin.

Anestrus↗
PubMed1987

The ability of DNA polymerase beta to synthesize DNA beyond the gap with displacement of the non-replicated strand.

Study was made of the ability of calf thymus DNA polymerases alpha and beta to replicate templates containing a small gap. It was found that during extensive replication of activated DNA or synthetic template.primers or specially prepared circular DNA containing a small gap, catalyzed by DNA polymerase alpha, the levels of incorporated nucleotides corresponded to the amounts of the single-stranded fraction of these templates. In contrast, in the reaction catalyzed by DNA polymerase beta the amounts of products were several times greater. The ability to synthesize the product in a great excess was a specific feature of the latter enzyme. An analysis of the gap-filling products by sucrose gradient centrifugation, gel electrophoresis and Southern hybridization showed that, contrary to DNA polymerase alpha, DNA polymerase beta exhibited the ability to synthesize DNA not only within but also beyond the gap. The "net" DNA product is complementary to the template strand. It is suggested that DNA was synthesized beyond the gap by displacement of the non-replicated strand.

Animals↗
PubMed1986

[Sex determination of cadaver material by the detection of specific nucleotide sequences of the Y chromosome following DNA cleavage].

A gene technological method of sex determination in cadaverous material is reported. The samples were taken from a child's corpse, which was nearly completely skeletonized after 1 year in water. From cells of the bone marrow the DNA was isolated and digested by restriction enzymes. A defined fragment of 2.12kb length was cleaved off by the endonuclease HaeIII in the presence of Y chromosomes. After agarose-gel electrophoresis of the DNA fragments, the specific sequence was detected by hybridization with the cloned, radioactively labelled complementary plasmide pHY2.1.

Autoradiography↗
PubMed1986

Immunocytochemical detection of peptides in the guinea pig cochlea.

The cochleae of juvenile guinea pigs were investigated for the presence of several neuropeptides. Glucagon, insulin, CCK and beta-endorphin immunoreactive neurons and nerve fibers as well as hair cells were demonstrated by the peroxidase antiperoxidase technique. Small amounts of substance P were also found in different sites in the inner ear. In contrast, prolactin-like material could not be found at all. These findings have significance with regard to the putative role of neuropeptides in neuromodulation.

Animals↗
PubMed1986

Neuropeptides in macula utriculi and macula sacculi of guinea pig labyrinth. An immunohistochemical study.

The neuropeptides Substance P, beta-Endorphin, Prolactin, Cholecystokinin, and Glucagon were investigated by means of Sternbergers PAP technique in the neuroepithelium of the Maculae utriculi and sacculi of the labyrinth of newborn guinea pigs. This brief report will show the localization of some neuropeptides in the neuroepithelium of the Maculae utriculi and sacculi. We could not find information about similar studies on this topic in the literature. In connection with investigations of the sensory apparatus of the inner ear we have recently presented neuropeptides evidence for the presence of certain peptides in the Ggl. spirale and the hair cells of the organ of Corti. With this paper we continue to report on neuropeptides in the labyrinth of the juvenile guinea pig as revealed by immunohistochemistry (Nowak et al., in press).

Acoustic Maculae↗
PubMed1986

Ballistics: a pathophysiologic examination of the wounding mechanisms of firearms: Part I.

Wounds caused by firearms are a frequent occurrence in urban emergency centers. Understanding of the underlying pathophysiologic mechanisms involved in wound production is very important in treatment of these injuries. Part I of this article reports studies on the interaction of projectiles with both the atmosphere and human tissue to produce wounds. Part II will examine the types of wounds formed by specific firearms, and the recent innovations in both weapons and ammunition which are altering the severity of shooting injuries.

Animals↗
PubMed1986

Effect of stress on calcium homeostasis in sheep.

The acute effect of stress on the plasma and cerebrospinal fluid (CSF) immunoreactive parathyroid hormone (PTH) response was studied in 6 merino sheep. Stress was exerted by weak periodical electric square waves (PESW). In addition, the effect of intravenous injection of adrenaline was studied. Under stress conditions (PESW or adrenaline injection), plasma PTH increased up to 30% and up to 50%, respectively. Weak periodical electric square waves of 3-4 mA decreased CSF PTH concentrations by up to 50%. The effect of adrenaline injection on the CSF PTH was not significant. Total calcium and magnesium in plasma and CSF did not change. Our results showed that the effect of stress on the CSF PTH is opposite to the effect on plasma PTH, and suggest that both, PESW and adrenaline, affected PTH in plasma and CSF by a Ca-independent mechanism.

Animals↗