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At least 523 records · Page 29Linked to original sources
PubMed1996

Validation of precision-cut liver slices in dynamic organ culture as an in vitro model for studying CYP1A1 and CYP1A2 induction.

The utilization of precision-cut liver slices in dynamic organ culture as an in vitro model was validated by comparing the induction of the biomarker responses following in vitro (rat liver slice) and in vivo exposure of rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The biomarker responses investigated were cytochrome P450s 1A1 and 1A2 (CYP1A1 and CYP1A2) mRNA, protein, and activities. Precision-cut rat liver slices were incubated in dynamic organ culture for 24 hr with medium containing 0.001-10 nM TCDD or medium without TCDD (control). The resultant mean TCDD concentration in the slices ranged from 19 to 80,925 ppt (wet wt), respectively. A concentration-dependent induction of CYP1A1 mRNA, protein, and activities and a more modest induction of CYP1A2 mRNA was observed in liver slices at all medium concentrations of TCDD. The O-demethylation of 7-methoxyresorufin, a marker for CYP1A2 activity, was induced at TCDD medium levels of 0.01 nM and greater, whereas a detectable increase in CYP1A2 protein occurred only at the higher concentrations. Comparable liver concentrations of TCDD (8-64,698 ppt wet wt) were achieved at 24 hr following a single in vivo exposure of rats to TCDD at doses ranging from 0.002 to 5 microg/kg po. Concentration-effect and dose-response relationships for induction of CYP1A1 and CYP1A2 were similar following in vitro and in vivo exposure to TCDD, although the magnitude of induction was greater for in vivo exposure. The data support the use of liver slices in dynamic organ culture for assessing the relative in vivo potency of a compound to induce CYP1A1 and CYP1A2. Human tissue can also be readily utilized in this in vitro model to predict the biological and toxicological effects of a given in vivo exposure to TCDD.

Animals↗
PubMed1984

The reliability of frozen-section diagnosis in various breast lesions: a study based on 3451 biopsies.

In this study, we analyze breast biopsy material over a 5-year period and we compare the results of frozen-section diagnosis with the corresponding diagnosis of the permanent histologic sections. In this study, which represents the largest series in the available international literature, it is proven that frozen-section diagnosis of various breast lesions is a highly accurate procedure in spite of the difficulties facing the pathologist with the frequent borderline or premalignant lesions. The great responsibility of the pathologist is emphasized.

Biopsy↗
PubMed1990

Visualization of brain monoamine oxidase B (MAO-B) in dementia of Alzheimer's type by means of large cryosection autoradiography: a pilot study.

Quantitative autoradiography, using 3H-deprenyl, was applied to study the regional localization of MAO-B in large cryosections from 3 control brains and 3 brains from patients with Alzheimer's disease (AD). High 3H-L-deprenyl binding was found in e.g. basal ganglia, cingulate gyrus, and insula cortex. Temporal cortex, parietal cortex, occipital cortex and various nuclei of the thalamus, showed moderate density, while low binding was observed in e.g. white matter. When the brains from the controls were compared with those with AD, the mean values for 3H-deprenyl binding was higher in the latter group, however, more generalised than previously reported.

Aged↗
PubMed1991

A horseradish peroxidase study of the fiber orientation in the facial nerve.

Horseradish peroxidase (HRP) was used to investigate the motor fiber orientation in the cat's intratemporal facial nerve. When HRP was applied to the zygomatic rami, HRP-labeled fibers were distributed diffusely throughout the labyrinthine and tympanic segments. On the other hand, distal to the chorda tympani entrance, a well-defined topographical orientation was found in the posterolateral aspect of the nerve. When HRP was applied to the buccal rami, topographical orientation was found in the posteromedial area of the distal mastoid segment. When HRP was applied to the posterior auricular rami, topographical orientation was found in the center to the anterior area of the distal mastoid segment. These results indicate that each branch of the facial motor nerve has a topographical orientation in the distal part of the mastoid segment, while nerve fibers are dispersed in the tympanic and labyrinthine segments.

Animals↗
PubMed1995

Three-dimensional structure of the gustatory cell in the mouse fungiform taste buds: a computer-assisted reconstruction from serial ultrathin sections.

Taste buds in fungiform papillae of the mouse were examined with transmission electron microscopy and computer-assisted, three-dimensional reconstruction from serial ultrathin sections. In accord with observation by Murray (1971), four distinct cell types, type I, II, III and basal cells, were identified. Of these, only the type III cell made synaptic contacts with nerve terminals and contained both small, clear vesicles and dense-cored granules. The former vesicles were synaptic-type and accumulated in the cytoplasm just below the synaptic in membrane thickenings. This finding clearly indicates a sensory function for the type III cell. One to three type III cells were identified within a taste bud. The type III cell had at most eight synapses with nerve terminals. One nerve fiber making two synapses with the type III cell was occasionally observed in its terminal region.

Animals↗
PubMed1994

A comparison of large block macrosectioning and conventional techniques in breast pathology.

Two techniques for the histological handling of breast specimens, namely conventional sampling using small blocks (SB) and a large block (LB) macrosectioning technique have been compared, with special emphasis on tumour size and in situ carcinoma, in an attempt to objectively demonstrate the advantages of the latter method. This is considered to be of particular importance in guiding the clinicians in their use of the many treatment modalities available for breast carcinoma. All cases were from the routine surgical caseload; 100 examined by the LB technique and 111 using conventional SB. The LB technique gave a reliable measurement of invasive carcinoma in 100% of cases compared to only 63% of SB cases. Ductal carcinoma in situ (DCIS), was found more frequently (80% versus 64%) and its extent was more easily and reliably measured in the large blocks. The extent of DCIS was significantly greater in all cases using large block techniques. Concurrent carcinomas were found more frequently in the LB series and these tumours were smaller than those in the SB series. Similar differences were noted with radial scars, and other proliferative lesions also had a higher incidence in the LB series. We conclude that the LB technique has sufficient advantages to recommend it as a standard technique in breast pathology.

Breast Neoplasms↗
PubMed1978

Substructure of inner mitochondrial membranes of myocardial cells as shown by cryo-ultramicrotomy.

The substructure of the inner mitochondrial membranes has been studied by cryo-ultramicrotomy under conditions during which denaturation of proteins by treatment with chemical solutes has been totally avoided. In such preparations, the inner membrane has a substructure consisting of globular subunits. These subunits have an average diameter of ca. 20 A-ca. 62 A and are fairly regularly spaced. Intracristal space is absent in the unstained, freeze-dried preparations, whereas a space of ca 40 A is seen in preparations lightly treated by OsO4-vapour. It is concluded that the subunits of the inner mitochondrial membranes probably consist either of single protein molecules or of complexes of protein molecules.

Animals↗
PubMed1977

Electron microprobe investigations into the process of hard tissue formation.

The electron microprobe microanalyser has been used to measure the concentrations of Ca, P and S in the predentine of young rat incisors. The specimens were prepared as alcohol embedded ultrathin sections, unfixed vacuum embedded dry cut ultrathin sections and as thin cryostat sections. The results show the influence of preparation on the measured compositions and indicate that Ca is tightly bound to the matrix, whereas P can be easily washed out. Measurements along the dentine-predentine border demonstrated zones of Ca enrichment, the average size of which suggests that the zones could be the prestages of calcospherites. A mineralisation mechanism is discussed in which the high Ca concentration activates pyrophosphosphatase or ATPase before the onset of nucleation.

Animals↗
PubMed1975

Tubular structures associated with intracytoplasmic spirochetes.

When tissues of spirochete-infected brine shrimp (Artemia salina) were examined by electron microscopy, tubular structures were often seen closely associated with intracytoplasmic spirochete profiles. These tubules were never observed in association with spirochetes found in the haemocoeal or other extracellular spaces. Since the trilaminar layer comprising the wall of the tubules was identical in ultrastructure to the outer envelope of the spirochete, these structures were interpreted to be finger-like extensions of the spirochete outer envelope.

Animals↗
PubMed1980

Neuroanatomical identification of the frog habenular connections using peroxidase (HRP).

A study of the habenular nuclei connections by means of horseradish peroxidase (HRP) has never been carried out in amphibia. In the present paper we have investigated the afferent projections of the left and right habenular nuclei of the frog Rana esculenta using this technique. Cells, labelled by HRP, were either in a Golgi-like pattern or in a granular pattern. It appears that the habenular nuclei on the two sides of the epithalamus do not show different connections even though they are morphologically asymmetric. In fact, each habenula is connected bilaterally with the septal area and the bed nucleus of the hippocampal commissure, and ipsilaterally with the hypothalamic areas, the entopeduncular nucleus, the periventricular gray of the third ventricle and the interpeduncular nucleus. However, the habenular commissure has typical commissural fibres which apparently do not involve the medial portion of the left habenula. The habenular connections in the frog are generally similar to those reported in the literature for mammals. In addition, our results show the possibility that HRP is transported both retrograde and anterograde.

Animals↗
PubMed1995

Distribution of aspartate and glutamate in the nucleus of the solitary tract of the lamb.

Excitatory amino acids have been implicated in several nucleus of the solitary tract (NST)-mediated functions. The distribution of the excitatory amino acids aspartate and glutamate has been described in both cat and rat. However, the distribution of these amino acids has not been described for the lamb, a species frequently used in the investigation of NST-mediated behaviors. Thus, this study was designed to investigate the distribution of aspartate-like (ASP) and glutamate-like (GLU) immunoreactivity in the lamb NST using pre- and post-embedding immunohistochemistry. Both ASP- and GLU-immunoreactive cells and puncta were observed throughout the rostral to caudal extent of the lamb NST. The most intense ASP- and GLU-immunoreactive cell and puncta staining was found ventromedial, ventral and ventrolateral to the solitary tract at intermediate and caudal levels of the lamb NST. The relative numbers of both cells and puncta stained were lower at rostral levels of the NST corresponding to the gustatory NST. The intense ASP and GLU immunoreactivity observed in areas of the lamb intermediate and caudal NST that are involved in respiration, deglutition and cardiovascular functions suggests excitatory amino acids plays an important role in NST neural processing that underlies these behaviors in lamb.

Animals↗
PubMed1990

Muscle fiber typing in routinely processed skeletal muscle with monoclonal antibodies.

Muscle fiber typing is conventionally performed using mATPase enzyme histochemistry on cryostat sections. After pre-incubation of sections at pH 4.3, 4.6 and 10.3, based on the pattern of enzyme reactivity, the fibers can be classified in types I, II (subtypes A, AB and B) and the intermediate C (I and II) fibers. We have attempted to perform fiber typing of human psoas muscle by immunohistochemistry, using monoclonal antibodies R11D10 (specific for cardiac and type I skeletal myosin) and MY-32 (specific for fast muscle fibers) on cryostat as well as on paraffin sections. Staining of consecutive cryostat sections showed that type I fibers are R11D10 reactive whereas type II fibers are MY-32 reactive. Subtyping of type II fibers could not be performed by immunohistochemistry. Quantitative analysis of type I and II fibers showed that enzyme histochemical and immunohistochemical analysis are in close agreement.

Antibodies, Monoclonal↗
PubMed1990

Microphotometric determination of enzymes in brain sections. II. GABA transaminase.

The tetrazolium salt procedure of van Gelder (1965) for the demonstration of GABA transaminase (GABAT; the most important GABA degrading enzyme) was adapted for microphotometric measurements of GABAT activities in brain sections using the hippocampus of rats as selected brain region. The final incubation medium consisted of 50 mM GABA, 5 mM alpha-ketoglutarate, 7 mM NAD, 10 mM sodium azide, 6 mM nitroblue tetrazolium chloride, 20 mM malonate and 15% polyvinyl alcohol in 0.05 M Hepes buffer; the final pH was 8.0. There was a linear relationship between GABAT activity and section thickness up to 14 microns and between GABAT activity and reaction time at least up to 20 min (kinetic and end-point measurements). Phenazine methosulfate as an exogenous electron carrier and pyridoxal-5-phosphate as coenzyme of GABAT did not enhance the demonstrable GABAT activities, whereas sodium azide as a blocker of the respiratory chain resulted in an increase of demonstrable enzyme activities. A coreaction of succinate dehydrogenase was excluded by the use of malonate (competitive inhibitor). Using the incubation medium described GABAT activities were demonstrated via the endogenous enzymes succinic semialdehyde dehydrogenase and NADH tetrazolium reductase which were shown to be not rate limiting and seems to be similarly localized as GABAT.

4-Aminobutyrate Transaminase↗