An autoradiographic analysis of the mode of proliferation in the buccal mucosa of rats incubated up to 5 hours

This study was concerned with the course of DNA synthetic activity (3H-TdR-LI-method) in the buccal mucosa of adult male. Sprague Dawley rats over an incubation period of 5 h. Interest was focussed on the influences of different media and, in particular, on temoporary changes in the proliferative activity. 3H-LI were compared in specimens (a) kept in active (= i.e., 3H-thymidine containing) medium throughout their respective incubation period and (b) pre-incubated in inactive medium for varying, but clearly defined periods before being transferred into active medium for 30 min (actual 3H-LI). Independent of the medium used the rate of DNA synthesis was markedly lowered at 60 min, the reduction being more or less significant in the different media. This was due to a temporary inhibition of DNA synthesis, which was restored after 120-180 min. In contrast, the blockade of G2-phase and/or mitosis persisted up to the end of incubation, as indicated by the unchanged number of labelled mitotic figures after 120 min. Addition of glutamine to Mc Coy's 5A markedly enhanced the activity of 3H-thymidine incorporation, but could not prevent the temporary inhibition of DNA synthesis. The biochemical mechanisms relevant for cell proliferation have been reviewed and correlated to the present results.     

Ethanol potentiates in vivo hepatotoxicity of endosulfan in adult male rats.

In an attempt to evaluate the effect and interaction of ethanol on endosulfan-induced hepatotoxicity in vivo to adult male rats, both, endosulfan (7.5 mg/kg body wt) and ethanol (1.5 g/kg body wt) were studied separately as well as in combination after a chronic oral exposure of 30 days. When fed separately, both the agents were found to induce microsomal mixed function oxidase (MFO) system in treated animals. A simultaneous induction in the activity of cytosolic GSH-s-transferase was found to be associated with significantly induced ascorbate-induced microsomal lipid peroxidation. Both endosulfan and ethanol showed increasing trends in the activities of reducing equivalent (NADPH)-generating enzymes in liver. The activity of hepatic alcohol dehydrogenase was, however, found to be relatively unaffected. When ethanol was administered in combination with endosulfan, the observed effects on the activities of major drug metabolizing enzymes, microsomal lipid peroxidation and NADPH generation were further pronounced. Findings demonstrated the MFO inducing capability of both endosulfan and ethanol, and showed further that chronic ethanol ingestion might potentiate the in vivo hepatotoxicity of endosulfan if administered in combination.     

Circadian variations of the plasma proteins in the adult male rat under natural synchronisation (author's transl)]

Circadian rhythms of blood total proteins, albumin, alpha 1-, alpha 2-, beta- and gamma-globulins were documented in 80 Wistar SPF adult male rats, synchronized by natural light (06.00-18.00 h) and darkness (18.00-06.00 h) during the month of October 78. Blood was sampled at four fixed time points in the 24 h scale (i.e. 04.00, 10.00, 16.00 or 24.00 h). Total proteins, albumin, alpha 2- and gamma-globulins showed a statistically significant rhythm with a maximum at 04.00 h. The data obtained in anaesthetized rats under artificial synchronization and in man are compared, taking into account that the rat is a nocturnally active rodent. The present work partially confirms the hypotheses of previous chronopharmacological studies, thus e.g. curarizing substances have a mimimum activity when the protein plasma level, especially albumin, is the highest.     

Azoindoxyl methods for the histochemical investigation of hydrolases. I. Lactase (lactase-beta-glucosidase complex) (author's transl)]

An azoindozyl method for the histochemical demonstration of lactase (lactase-beta-glucosidase complex) is described. The incubation medium consists of 5 mg 5-Br-4-Cl-3-indolyl-beta-D-fucoside (dissolved in 0.5 ml N,N-dimethylformamide) and 0.02 ml hexazotized prosaniline in 10 ml 0.1 M citric acid phosphate buffer, pH 6-6.5. By means of this method lactase can be exactly localized in the brush border of the enterozytes in the jejunum of suckling rats. Compared to the corresponding indigogenic method the azoindoxyl reaction proceeds faster and the reaction product is often precipitated more precisely.     

Comparative studies on lactate dehydrogenase in serum and plasma of rats (author's transl)

Values of serum and plasma LDH in rats were comparatively studied, and the following results were obtained: 1) The activity of LDH increased in serum with time during clotting, but no changes of LDH activity were found in plasma. 2) When platelet rich plasma (PRP) was recalcified and allowed to clot, LDH-release from platelets with a corresponding increase of serum LDH was observed, but addition of ADP or thrombin to PRP did not have an effect on LDH-release. 3) LDH-release from platelets by calcium was not inhibited by aspirin, and it was influenced by the quality of the test tube. 4) Values of serum and plasma LDH on experimentally induced liver-damaged or kidney-damaged rats and tumor-bearing rats were examined in relation to their tissue damages, revealing that plasma LDH activity represents the condition of a disease better than serum LDH activity.     

Effect of the bilateral amygdaloid complex lesion on the hypothalamic l-leucinaminepeptidase activity in the male adult (author's transl)

The effect of bilateral lesion of the amygdaloid nuclear complex on the hypothalamic L-leucinaminepeptidase (LAP) activity has been studied in the rat. Amygdalectomized animals show an increase in this activity, specially when lesion extends to the whole complex or when the basolateral and basomedial nuclei remain intact. The increase in LAP activity is not so significant when the lesion does not affect the cortical nucleus.     

Localization of the haemopoietic tissue of polychaete annelids. I. Site of haemoglobin (erythrocruorin) synthesis (author's transl)

An iron rich tissue with an important pseudo-peroxidase activity and which specifically incorporates 55Fe and 3H delta aminolevulinic acid is localized around some vessels of the investigated Annelids : parapodial vessels of Nephthys, chloragogen coeca of Arenicola. This tissue which can be considered as haemopoietic has been studied at the EM level : it is characterized by numerous dense inclusions with pseudo-peroxidase activity and well developed granular endoplasmic reticulum and Golgi.     

DNA synthesis in the ventricular myocardium of young rats exposed to intermittent high altitude (IHA) hypoxia. An autoradiographic study.

Intermittent high altitude (IHA) hypoxia (7000 m) increased the wet weight of the right ventricular myocardium of 30-day-old rats after two 4 h/day exposures. During the same period the number of DNA-synthesizing nuclei of both muscle and non-muscle cell types increased proportionally. After 4 such exposures to hypoxia the number of 3H-thymidine-labelled nuclei in both cell types increased further. In addition, the number of labelled nuclei increased significantly in the yet un-enlarged left ventricle. While there was no difference in the number of DNA-synthesizing cells between the right and left ventricles in control animals, a significant increase in the number of cells involved in DNA synthesis in the right ventricle was found in both groups of animals exposed to IHA hypoxia. These results show that DNA synthesis in myonuclei of the ventricular myocardium can be stimulated in 30-day-old rats, i.e. at the very end of the weaning period.     

Prevalence and development of two Sarcocystis spp. in the horse (author's transl)

The prevalence of Sarcocystis spp. in horses was investigated in a survey at the Munich abattoir during 1978/79. Muscle specimens (oesophagus, diaphragm, sublingual muscle, myocardium) were examined using tryptic digestion. Out of 200 horses 31 (15.5%) were found to be carriers of sarcocysts. No parasites were found in the myocardium. In three animals sarcocysts could be isolated and differentiated in fresh preparations. Cysts with 5 to 11 microns by less than 0.5 microns hairlike, unstable protrusions were classified as Sarcocystis equicanis, whereas those with 2.5 to 4.5 microns by 0.8 to 1.0 microns fingerlike, stabile protrusions were assigned to be S. fayeri. Histologically S. equicanis cysts were thin-walled and S. fayeri cysts were thick-walled and often striated. For both species the dog acts as final host. A mixture of sporocysts of both species measured: 12.0--14.4 (13.4 +/- 0.7) X 9.3--10.5 (9.8 +/- 0.4) microns. The prepatent period is 11 to 17 days. Two ponies experimentally infected with 100,000 sporocysts each did not show clinical signs. In fresh preparations and in histopathological examinations of biopsied (111th, 130th, 152th, and 165th day post-infection (p.i.) and postmortem material (167th and 189th day p.i.) different developmental stages of sarcocysts of both species were seen and the following pathological alterations observed: circumscribed non-purulent inflammation, moderate Zenker's degeneration of muscle fibres, and degenerated cysts, of which sometimes only parts of the cyst wall were left. In fresh preparations S. equicanis and S. Fayeri could be differentiated 111 days p.i. The observed disappearance of the sarcocysts is suggested to be a self-cleaning process.     

Origin of adenovirus DNA replication. Role of the nuclear factor I binding site in vivo

An assay is described that detects in vivo a single round of initiation and DNA synthesis directed by a linear molecule containing an exposed single copy of an adenovirus (Ad) origin of replication. This and a previously described assay, which measures multiple rounds of DNA replication, were used to identify DNA sequences within the Ad2 and Ad4 origins of replication that are important for ori function. Linear DNA molecules containing sequences from the Ad2 or Ad4 genome termini were cotransfected with homologous and heterologous helper virus, and net amounts of DNA synthesis were compared. Linear molecules containing the Ad4 inverted terminal repeats were replicated 20-fold better in the presence of the homologous helper, whereas both Ad2 and Ad4 inverted terminal repeats were utilized efficiently by Ad4. DNA sequence analysis of the Ad2 ori and the corresponding region in Ad4 indicated that, although there are only ten variant base-pairs, eight are located within the Ad2 DNA sequence recognized by the cellular protein nuclear factor I. This protein is required to achieve the maximal rate of Ad2 DNA replication in vitro, and these differences therefore identify DNA sequences that are crucial to Ad2 ori function. The Ad4 ITR does not contain a functional nuclear factor I binding site, and deletion analysis has demonstrated that this region of the Ad4 genome is not required for ori function. In contrast to Ad2, the DNA sequences required for the initiation of Ad4 DNA replication were shown to reside entirely within the terminal 18 base-pairs of the Ad4 inverted terminal repeat.