A comparison of the resolution provided by different imaging systems and display media in surgery

A method for observing whole rat fetal viscera embedded in gelatin using an automatic slicing apparatus is described. Fetuses were immersed in Bouin's solution. Part of the thoracic and abdominal skin of each fetus was removed, and fetuses were immersed consecutively in sodium bicarbonate 30% in 70% ethanol, gelatin 15% in water, gelatin 30% in water, then embedded in fresh 30% gelatin. The gelatin blocks containing the fetuses were immersed in 10% formalin. After fixation, the block was sliced into 200 microns serial transverse sections using a rotor-slicer at a rotation speed of 120 rpm and a cutting speed of 25 mm/sec. Complete slicing of a single fetus required about 20 min. The advantages of the method presented here include: complete fetal serial sections are produced, thin and uniform sections are obtained easily, viscera can be identified easily, and observation can be carried out at any time after slicing. The method presented can be used to detect whole fetal visceral malformations in developmental toxicity tests.     

Nucleolar organizer regions in lymphomas: a quantitative study

Using a silver staining technique, nucleolar organizer region-associated proteins (Ag-NORs) have been studied in paraffin sections of 76 non-Hodgkin's lymphomas, five normal lymph nodes, and five lymph nodes. The mean number of nucleolar organizer regions per nucleus was 1.19 (SD:0.09) for normal lymphocytes, 3.04 (SD:0.14) for reactive lymph nodes, 2.79 (SD:0.44) for low-grade lymphomas, 6.33 (SD:1.58) for intermediate-grade lymphomas, and 10.53 (SD:1.97) for high-grade lymphomas. There were highly significant differences in Ag-NOR counts among the groups (p < 0.001). The Ag-NOR regions were often observed in nuclei in areas where nucleoli themselves were invisible. It is suggested that this method is useful in diagnostic histopathology and in differentiation of the grade of lymphomas.     

Calibrated histochemistry of myoglobin concentration in cardiomyocytes

This article describes the calibration of a histochemical method to determine the myoglobin concentration in individual cardiomyocytes. Calibration is based on paired microdensitometric determinations in sections stained for myoglobin and on biochemical myoglobin determinations in tissue samples from different hearts. In addition, the staining intensity of sections from gelatin blocks containing known amounts of myoglobin is determined. To construct a calibration line, sections stained for myoglobin must be corrected for the degree of shrinkage caused by glutaraldehyde fixation and biochemical myoglobin determinations must be corrected for interstitial space. As an example, the method is used to determine the myoglobin concentration in individual skeletal muscle fibers and in control and hypertrophied rat cardiomyocytes. The amount of myoglobin per cardiomyocyte nucleus is increased two- to threefold in hypertrophied cardiomyocytes, whereas changes in myoglobin concentration depend on the model of hypertrophy used.     

Use of ultra-thin window detectors for biological microanalysis

Films and bulk samples of Nylon, gelatin, Makrofol, epoxy resin, aminoplastic resin and sodium acetate have been used as models of biological samples. It is shown that the use of ultrathin window (UTW) detectors in scanning transmission and scanning electron microsopes permits the quantitative analysis of light elements, yielding a total element analysis with hydrogen estimated by difference or "guesstimated". Comparison with known concentrations of concentrations obtained by chemical analysis shows that X-ray microanalysis of selections by the peak to continuum ratio model and bulk samples by the phi(pz) model gives sufficiently accurate results for biological purposes. It is also shown that sections may be analysed by the standardless ratio model. The application of UTW detectors to total element analysis by quantitative elemental imaging is demonstrated of bulk biological samples. which have been freeze-substituted, embedded in epoxy resin and surface polished. The possibility of imaging the oxygen content of frozen-hydrated bulk tissue samples which have been surface polished is also demonstrated. This may lead to the imaging of water distribution in frozen-hydrated bulk samples of biological tissues. UTW detectors are also useful for detecting mass loss in organic samples by monitoring the decrease in oxygen counts and for detecting contamination by monitoring the increase in carbon counts. It is also shown that changes in carbon counts are good indicators of folds in sections.     

Pathology and pathogenesis of mucoviscidosis (author''s transl)

The section of the cat's mesotympanum, denuded of mucosa, to Silastic and gelatin film was studied and compared with the contralateral control ear, which was also denuded of mucosa. The ears were studied by horizontal pathological sections taken one, two, four, and six months post-lympanotomy and insertion of either gelatin film or Silastic. The Silastic, gelatin film and control ears were compared for inflammatory reaction, amount of fibrosis, and the quality and quantity of mucosal regeneration. The inflammatory reaction was increased in the ears with Silastic compared with their corresponding control ears or to the ears with gelatin film. The amount of fibrosis and the quality and quantity of mucosal regeneration was essentially the same in the Silastic, gelatin film, and control ears. This study shows that both substances are well tolerated in the middle ear and that neither substance stimulated or inhibited the regrowth of mucosa or fibrous tissue when compared with the control.     

In situ measurement of glutamate concentrations in the periportal, intermediate, and pericentral zones of rat liver

We developed a quantitative histochemical assay for measurement of local glutamate concentrations in cryostat sections of rat liver. Deamination of glutamate by glutamate dehydrogenase (GDH) was coupled to the production of formazan and formazan precipitation was used for colorimetric visualization. The method was tested and validated with gelatin model sections with known glutamate concentrations. Calibration graphs showed linear relationships with high correlation coefficients (> 96%) between glutamate concentrations or section thickness and absorbance values. The method was reproducible, with a constant percentage of 60 +/- 5% of glutamate being converted in gelatin model sections containing glutamate concentrations of 2 mM and higher. Glutamate concentrations were estimated in periportal, intermediate, and pericentral zones of liver lobules that contain low, intermediate, and high GDH activity, respectively. In fed adult male rat livers, periportal zones contained the highest concentrations of glutamate (approximately 14 mM) and intermediate and pericentral zones approximately 13 and 9 mM, respectively. On starvation, glutamate concentrations increased only in the small rim of pericentral cells that express glutamine synthetase, to approximately 15 mM. In livers of fetal and newborn rats, glutamate was homogeneously distributed, with a concentration of approximately 5 mM. In suckling rat liver, distribution of glutamate was still homogeneous but the concentration was increased to approximately 8 mM. These glutamate distribution patterns were in agreement with those detected immunohistochemically.     

Nucleolar changes in senescing WI-38 cells

Changes in the area, dry mass and morphology of nucleoli were studied during in vitro aging of WI-38 cells. Interferometric methods were used for nucleolar dry mass determinations. The results show that there is (1) an increase in the fraction of cells with one large nucleolus per nucleus, 17% at population doubling 27.3 vs. 93% at population doubling 41.2, (2) an increase in mean nucleolar dry mass (583% at the last doubling), and (3) an increase in mean nucleolar area (236% at the last doubling) with in vitro senescence of WI-38 fibroblast cells. A strong correlation (r = 0.92) between nucleolar dry mass and nucleolar area was demonstrated.     

铟电解精炼中添加剂明胶的影响及其机制研究

研究了明胶对阴极极化、电流效率、电解液比电阻的影响，研究了在电解过程中明胶的电析消失现象，探讨了明胶的作用机理。研究表明：明胶能增大阴极过电位，能提高阴极电流效率，提高电解液的比电阻。明胶的电析消失速度随电流密度的增大而增大。明胶极有可能与In^3 形成络合物的形式参与电解过程。     

Circular dichroic studies of the DNA and RNA of nucleoli

Circular dichroism (CD) in the 240-300-nm region was used to study the conformation of DNA and RNA complexed with proteins in isolated nucleoli form HeLa cells. Deoxyribonuclease or ribonuclease digestion was employed to obtain (1) the individual CD spectra of nucleolar DNA or RNA in complex form with proteins, or in free form; and (2) the experimental CD baseline correction to exclude contributions from nonnucleic acid sources such as light scattering artifacts and proteins. The CD spectrum of nucleolar DNA in DNA-protein complexes was highly reduced in ellipticity in comparison with protein-free DNA. It showed a positive peak at 283 nm with a molar ellipticity [theta]283 = 1200 deg cm2 dmol-1 and a crossover at 262 nm. Addition of sodium dodecylsulfate shifted the peak to 276 nm with [theta]276 8000 deg cm2 dmol-1 and a crossover at 254 nm. The CD spectrum of nucleolar RNA in RNA-protein complexes was also reduced in comparison with protein-free RNA, showing a peak at 269 nm ([theta]269 = 6900 deg cm2 dmol-1), and a crossover at 250 nm. Addition of sodium dodecyl sulfate shifted the peak to 265 nm with [theta]265 = 18 000 deg cm2 dmol-1 and a crossover at 246 nm. The low ellipticity of both nucleolar DNA and RNA when complexed with proteins was increased by treatment with sodium chloride, urea, or heparin. This suggests that some ionic, hydrophobic, and hydrogen bondings are involved in the nucleic acid-protein interaction in nucleolar chromatin similar to that observed in nuclear chromatin.     

Nucleolar localization elements of Xenopus laevis U3 small nucleolar RNA

The Nucleolar Localization Elements (NoLEs) of Xenopus laevis U3 small nucleolar RNA (snoRNA) have been defined. Fluorescein-labeled wild-type U3 snoRNA injected into Xenopus oocyte nuclei localized specifically to nucleoli as shown by fluorescence microscopy. Injection of mutated U3 snoRNA revealed that the 5' region containing Boxes A and A', known to be important for rRNA processing, is not essential for nucleolar localization. Nucleolar localization of U3 snoRNA was independent of the presence and nature of the 5' cap and the terminal stem. In contrast, Boxes C and D, common to the Box C/D snoRNA family, are critical elements for U3 localization. Mutation of the hinge region, Box B, or Box C' led to reduced U3 nucleolar localization. Results of competition experiments suggested that Boxes C and D act in a cooperative manner. It is proposed that Box B facilitates U3 snoRNA nucleolar localization by the primary NoLEs (Boxes C and D), with the hinge region of U3 subsequently base pairing to the external transcribed spacer of pre-rRNA, thus positioning U3 snoRNA for its roles in rRNA processing.     

烟煤胶质层指数准确度的试验

介绍了烟煤胶质层指数的测定方法,分析了煤样粒度、装样量、升温速度等对烟煤胶质层指数测定的影响,对传统法与半自动法的胶质层指数测定准确度进行了试验,该试验结果准确,能满足邯钢焦化厂的生产需要。     

The nucleolar fibrillar centres in various cell types in vivo or in vitro

Nucleoli were studied in chick fibroblasts cultured in vitro, under normal or under experimental conditions, and in several mammalian cell types in vivo. All these cells frequently contain nucleoli with fibrillar centres. The nucleolar fibrillar centres are composed of fibrous material of low electron density and are always intimately associated with the dense fibrillar component. Their morphology is very similar to that analysed cytochemically in Ehrlich tumour cells. It therefore appears that they could be related to the nucleolar organizers as suggested in Ehrlich tumour cells.     

Nucleolar organizer regions in human maxillary sinus squamous cell carcinoma

A silver colloid technique for nucleolar organizer regions (AgNOR) was applied to paraffin sections of maxillary sinus squamous cell carcinomas (MSSCC) of 25 patients. The patients were divided into two groups, one with MSSCC recurring in the primary lesion after treatment with radiotherapy, chemotherapy and/or surgery and one without recurrence. Notable differences between the numbers of NOR in neoplastic epithelia and the normal mucosa were observed (P = 0.0001), but there were no differences between the numbers of NOR in the recurrent and non-recurrent carcinomas. This investigation found no prognostic importance in the number of AgNOR in MSSCC.     

Screening of Australian medicinal plants for antiviral activity

The nanoencapsulation of a model protein drug, bovine serum albumin (BSA), using gelatin as the matrix material is reported. Nanoencapsulation was conducted using a modified water-in-oil (w/o) emulsion method, which is emulsifier-free and simple. The nanoencapsulation product, BSA-containing gelatin nanoparticles, is characterized in terms of nanoparticle morphology, size and size distribution, water content, and in vitro protein release. The BSA-containing gelatin nanoparticles obtained from this nanoencapsulation process are nearly spherical and have a log-normal size distribution. The average diameter of the BSA-containing gelatin nanoparticles is approximately 840 nm. They can absorb 51-72% of water. In vitro release experiments demonstrate that BSA has been successfully encapsulated in, and can be released from the gelatin nanoparticles. The release of BSA from the gelatin nanoparticulate matrix follows a diffusion-controlled release mechanism. It is found that temperature affects both the water content and the BSA release rate of the gelatin nanoparticles.     

Regional differences in bromodeoxyuridine uptake, expression of Ki-67 protein, and nucleolar organizer region counts in glioblastoma multiforme

To investigate intratumoral differences in indices of tumor cell proliferation, we measured the bromodeoxyuridine labeling index (BrdUrd LI), the Ki-67 protein proliferating cell indices (PCIs) determined by monoclonal antibody MIB 1 in microwave-processed paraffin sections (MIB 1 PCI) and in some cases by monoclonal antibody in frozen sections (Ki-67 PCI), and counts of argyrophilic nucleolar organizer regions (AgNORs) in 20 glioblastomas. In the most actively proliferating areas, MIB 1 and Ki-67 PCIs correlated well with the BrdUrd LI and with each other, while AgNOR counts correlated less strongly with these indices. In less active areas, the MIB 1 PCI and BrdUrd LI changed concomitantly from one area to another within a tumor except in areas of pseudopalisading with necrosis; in these areas the BrdUrd LI decreased significantly compared with neighboring tumor tissue, while the MIB 1 PCI did not. There was very little staining of gemistocytic nuclei with either anti-BrdUrd or MIB 1 monoclonal antibodies; this supports the concept that gemistocytes are mainly quiescent cells. AgNORs in all of the above-mentioned areas varied from tumor to tumor, which suggests that they may indicate some cellular activity other than proliferation. The close correlation between the BrdUrd LI and Ki-67 protein PCIs in corresponding regions of glioblastomas suggests that MIB 1 staining of microwave-processed paraffin sections can be used to evaluate the growth potential of individual glioblastomas and possibly of other gliomas as well.     

Topogenesis of a nucleolar protein: determination of molecular segments directing nucleolar association

To identify the element(s) in nucleolar proteins which determine nucleolus-specific topogenesis, we have used different kinds of cDNA constructs encoding various chimeric combinations of mutants of the constitutive nucleolar protein NO38 (B23): 1) with an amino terminally placed short "myc tag"; 2) with two different carboxyl terminally attached large alpha-helical coiled coil structures, the lamin A rod domain or the rod domain of vimentin; 3) with the sequence-related nucleoplasmic histone-binding protein nucleo-plasmin; and 4) with the soluble cytoplasmic protein pyruvate kinase. To avoid the problem of formation of complexes with endogenous wild-type (wt) molecules and "piggyback" localization, special care was taken to secure that the mutants and chimeras used did not oligomerize as is typical of protein NO38 (B23). Using microinjection and transfection of cultured cells, we found that the segment comprising the amino-terminal 123 amino acids (aa) alone was sufficient to effect nucleolar accumulation of the construct molecules, including the chimeras with the entire rod domains of lamin A and vimentin. However, when the amino-terminal 109 aa were deleted, the molecules still associated with the nucleolus. The results of further deletion experiments and of domain swaps with nucleoplasmin all point to the topogenic importance of two independent molecular regions located at both the amino- and carboxyl-terminal end. Our definition of dominant elements determining the nucleolar localization of protein NO38 (B23) as well as of diverse nonnucleolar proteins will help to identify its local binding partner(s) and functions, the construction of probes examining other proteins or sequence elements within the nucleolar microenvironment, and the generation of cells with an altered nuclear architecture.     

Vascular characteristics of the lamina terminalis of the human hypothalamus

The aim of the study is to discover the sources of vascularization, vascular area, the size and density of the capillary network of the vascular organ of the laminae terminalis of the hypothalamus. The brain blood vessels under examination were filled with a mixture of India ink and gelatin. The serial paraffin sections of 30 and 200 um were cleared after Spalteholz. In the vascularization of this neuroendocrine structure of the hypothalamus, two arterial stems take part with their branches: a cerebri anterior and a. communicans anterior. In order to quantify the density of the capillary network, the authors used standard stereologic parameters - volumene density, surface density and mean radius of blood vessels. While the precise functions of the vascular organ have yet to be fully elucidated, the similarity in organization of this region to the median eminence has led several authors to suggest a neurosecretory role for the vascular organ of the lamina terminalis.     

The relationship of ribosomal RNA synthesis to the formation of segregated nucleoli and nucleolus-like bodies

The relationship of ribosomal RNA (rRNA) synthesis to nucleolar ultrastructure was studied in partial nucleolar mutants of Xenopus laevis. These mutations are the result of a partial deletion of rRNA genes and therefore alow studies on nucleolar structure and function without using drugs that inhibit rRNA synthesis. Ultrastructural studies demonstrated that normal embryos have reticulated nucleoli that are composed of a loose meshwork of granules and fibrils and a typical nucleolonema. In contrast, partial nucleolar mutants in which rRNA synthesis is reduced to less than 50% of the normal rate have compact nucleoli and nucleolus-like bodies. The compace nucleoli contain granules and fibrils, but they are segregated into distinct regions, and a nucleolonema is never seen. Since other species of RNA are synthesized normally by partial nucleolar mutants, these results demonstrate that nucleolar segragation is related specifically to a reduction in rRNA synthesis. The nucleolus-like bodies are composed mainly of fibrils,and the number of such bodies are composed mainly of fibrils, and the number of such bodies present in the different nucleolar mutants is inversely related to the relative rate of rRNA synthesis. Although the partial nucleolar organizers produce segregated nucleoli in these mutants, they organize morphologically normal, but smaller, nucleoli in heterozygous embryos. Alternative explanations to account for these results are discussed.     

SnoRNAs as tools for RNA cleavage and modification

Eukaryotic small nucleolar RNAs (snoRNAs) influence rRNA synthesis at two stages: nucleolytic processing and selection of nucleotides to be ribose methylated (Nm) or converted to pseudouridine (psi). The two modification functions and some processing activities involve direct base pairing of snoRNA with rRNA. In addition to rRNA-targeting sequences, snoRNA function depends on the presence of conserved box elements involved in snoRNA synthesis and localization. The present investigation is directed at using snoRNAs as tools for two purposes: 1) introducing nucleotide modifications into novel sites in rRNA and other snoRNAs, and: 2) targeting nucleolar RNAs for destruction using snoRNA:ribozyme chimers ('snorbozymes'). Early results demonstrate that snoRNAs can be used for both applications.     

A clinical experience with a hierarchically controlled myoelectric hand prosthesis with vibro-tactile feedback

The decline of plasma fibronectin after surgery, trauma, and burn, as well as during severe sepsis after injury, appears to limit hepatic Kupffer cell phagocytic activity. Intravenous infusion of gelatin-coated particles to simulate blood-borne particulate collagenous tissue debris in the circulation after injury also depletes plasma fibronectin. We used soluble gelatin conjugated with 125I-labeled dilactitol tyramine (DLT-gelatin) as a model of soluble collagenous tissue debris. We studied its blood clearance as well as organ localization in normal and postburn rats. Fibronectin-deficient plasma harvested early after burn exhibited limited ability to support in vitro phagocytic uptake of the gelatinized microparticles by Kupffer cells in liver tissue from normal rats. However, Kupffer cells in liver tissue from normal and postburn rats phagocytized the test particles at a normal rate when incubated in normal plasma. The DLT-gelatin ligand bound to fibronectin in a dose-dependent manner as verified by its capture with anti-fibronectin coated plastic wells when coincubated with purified fibronectin. By gel filtration chromatography, the binding of fibronectin with the DLT-gelatin ligand was readily detected, resulting in the formation of a high-molecular-weight complex. In normal animals the plasma clearance and liver localization of 125I-DLT-gelatin was competitively inhibited by infusion of excess nonradioactive gelatin. The blood clearance and liver localization of the soluble gelatin ligand were also impaired after burn injury during periods of fibronectin deficiency similarly to the pattern observed with gelatin-coated microparticles. By autoradiography, the cellular site for the uptake of the 125I-DLT-gelatin was primarily but not exclusively hepatic Kupffer cells; 125I-DLT-asialofetuin and 125I-DLT-ovalbumin were removed by hepatocytes and sinusoidal endothelial cells, respectively. Thus, gelatin conjugated with 125I-DLT can be used to simulate blood-borne soluble collagenous tissue debris after burn. It rapidly binds to plasma fibronectin before its hepatic Kupffer cell removal, and its blood clearance is markedly delayed after burn injury during periods of plasma fibronectin deficiency.