Search PubMed⌕ Search

Biomedical subjects

H Martin

Publications and source records attributed to H Martin.

At least 19 recordsLinked to original sources
PubMed1992

Serotonin-like immunoreactivity in Merkel cells and their afferent neurons in touch domes from the hairy skin of rats.

Immunoreactivity to serotonin was observed in Merkel cells as well as the afferent type I nerves terminating upon them in touch domes excised from the belly skin of rats. Type I nerves were strongly immunoreactive and could be traced through the dermis of the domal papilla. Merkel cell immunoreactivity was sometimes seen in the entire cell, but was often localized in the Merkel cell cytoplasm adjacent to nerve terminals and may have been in the terminals themselves. Domes were fixed by immersion in 4% paraformaldehyde-lysine-sodium-m-periodate (PLP) fixative at 4 degrees C for 2.5-3 hours and cryoprotected in 30% sucrose overnight. Sections were processed with the avidin-biotin complex peroxidase (ABC), peroxidase-antiperoxidase (PAP), and indirect immunofluorescence techniques with rabbit antiserum generated against serotonin.

Afferent Pathways↗
PubMed1992

Temporal and spatial regulation of a novel gene in barley embryos.

The temporal and spatial pattern of expression of a novel barley gene is described. The gene has been identified through the differential screening of a cDNA library constructed to poly(A)+ RNA of zygotic embryos. Transcripts corresponding to the cDNA, pZE40, become abundant in the non-axial tissues of the developing embryo within 8-10 days after anthesis, when steady-state levels are high in the scutellum, coleoptile and coleorhiza, with the exception of the scutellar epithelium. This expression pattern is maintained throughout maturation of the embryo until levels eventually decline as the grain desiccates. On germination, there is a transient re-appearance of mRNA to pZE40, with accumulation specifically restricted to the scutellum of the seedling. In situ hybridization has enabled the detection of transcripts elsewhere in the barley plant, in highly localized groups of cells. The timing and cell specificity of expression suggests the gene product is involved in the synthesis and/or transport of metabolites.

Base Sequence↗
PubMed1992

Karyotypes in 90 human gliomas.

Cytogenetic studies were performed on 90 human gliomas including 26 astrocytomas, 12 oligodendrogliomas, three oligo-astrocytomas, seven ependymomas, eight pilocytic astrocytomas, and 33 malignant gliomas (anaplastic astrocytomas and glioblastomas). The most common abnormalities were trisomy 7 in 23 cases, monosomy 22 in 15 cases, losses of the Y chromosome in 19 of 50 male cases, and losses of the X chromosome in 10 of 39 female cases. There are evident differences between the particular subgroups of gliomas. Monosomy 10 and double minutes are typical for malignant gliomas. The 58 determined chromosomal breakpoints were located on 45 different sites. Chromosomes 1, 9, 6, 3, 10, and 17 were predominantly involved.

Adult↗
PubMed1992

Histomorphometric comparison of canals prepared by four techniques.

Numerous methods of root canal preparation have been recommended and used by clinicians. This study used histomorphometrics to determine the area of root canal preparations using four currently popular techniques. Clinicians that were highly skilled in each technique prepared curved canals in acrylic blocks. Each clinician described this technique and discussed the technique with regard to the use of acrylic blocks as compared with dentin. Analysis of the areas of the root canals after preparation revealed a significant difference among the groups. The mean areas after treatment were step-back technique, 17.33 mm2; Cavi-Endo technique, 15.87 mm2; Canal Master technique, 13.56 mm2; and balanced force technique, 17.31 mm2. Photographs of the blocks used in the study were included for inspection by the reader.

Dental Cavity Preparation↗
PubMed1992

Proliferating cell nuclear antigen (PCNA) in atypical and malignant meningiomas.

Because it is not easy to determine the tumor status of meningiomas by current diagnostic procedures, we investigated these tumors immunohistochemically using the monoclonal antibody PC 10. This antibody recognizes a fixation- and processing-resistant epitope of the proliferating cell nuclear antigen (PCNA), which is a 36-KD nuclear antigen associated with the cell cycle. We studied paraffin-embedded and formalin-fixed tissue specimens of a group of 21 atypical/malignant meningiomas together with 18 benign meningiomas. PCNA staining results were compared with the mean number of silver-stained nucleolar organizer region-associated proteins (AgNORs), tumor grading, and mitotic indices of these tumors. The percentage of PCNA-positive cells was found to range between 0.1% and 40%, irrespective of the tumor grade. When all tumors were collectively considered, no positive correlation was found between PCNA scores and histologic grading and only a weak one between PCNA score and mitotic index. A higher correlation was seen between AgNOR counts and tumor grading. Our results suggest that PCNA labeling and histologic grading seem to be independent parameters. The correlations found between AgNOR counts and tumor grading should be substantiated in further series.

Antigens, Nuclear↗
PubMed1992

Comparative effects of a recommended lipid-lowering diet vs a diet rich in monounsaturated fatty acids on serum lipid profiles in healthy young adults.

This crossover study investigated the effects of two fat-reduced diets, one rich in monounsaturated fatty acids (MUFAs), the other rich in polyunsaturated fatty acids (PUFAs), on serum lipid profiles in 38 healthy young adults initially on a typical western diet. After being randomly assigned to two groups, the subjects received the MUFA or PUFA diet for 3-wk and then the other diet for 3 wk. Both test diets led to significant reductions in serum cholesterol, LDL cholesterol, and HDL cholesterol (P less than 0.001). Both reduced apolipoprotein B (P less than 0.001) and apolipoprotein A-I concentrations (P less than 0.01 for the MUFA, P less than 0.001 for the PUFA diet). Apolipoprotein A-I was significantly higher on the MUFA than on the PUFA diet. The ratio of apolipoprotein A-I to B significantly increased on both diets. Thus, a low-fat, MUFA-rich diet is as effective as a low-fat, PUFA-rich diet in lowering total and LDL cholesterol, but both also lowered HDL cholesterol concentrations. The MUFA-rich diet may be more advantageous than the PUFA-rich one because it does not lower apolipoprotein A-I concentrations as much as the PUFA-rich diet.

Adult↗
PubMed1992

Influence of preoperative dexamethasone therapy on proliferating cell nuclear antigen (PCNA) expression in comparison to other parameters in meningiomas.

We conducted a trial in 42 benign and malignant meningiomas to assess a possible influence of preoperative dexamethasone therapy on mitotic index, labelling indices of proliferating cell nuclear antigen (PCNA), progesterone receptor, epidermal growth factor receptor (EGF-R), c-erbB-2 oncoprotein, cathepsin D, gamma-gamma enolase as well as the mean number of silver-stained nucleolar organizer region-associated proteins (AgNORs). Tumors with preceding dexamethasone therapy for more than 1 day display significantly less immunohistochemical staining for PCNA. A correlation between the labelling index of PCNA and the degree of malignancy could not be identified. There was no significant effect of preoperative dexamethasone therapy on the other parameters. Our data suggest that dexamethasone may selectively inhibit the expression of PCNA in the G1/S-phase of the cell cycle. Thus, we emphasize the necessity to heed factors, e.g. dexamethasone, which may affect the expression of proliferating markers.

Adult↗
PubMed1992

Nucleolar organizer region-associated proteins in cancer cells. Quantitative investigations on gliomas, meningiomas, urinary bladder carcinomas and pleural lesions.

Using a modified silver staining technique, we investigated nucleolar organizer region-associated proteins (AgNORs) in paraffin sections of 156 neoplastic tissues and other lesions, including gliomas (n = 41), meningiomas (n = 20), urinary bladder carcinomas (n = 58), and neoplastic and reactive lesions of the mesothelium of the pleural cavity (n = 37). We found significant differences in the mean number and area of AgNORs per nucleus between nonanaplastic and anaplastic astrocytomas. In meningiomas AgNOR analysis may be useful to distinguish between mostly benign tumors (grade 1 tumors) and atypical ones. Urinary bladder carcinomas exhibited a statistically significant increase in both AgNOR number and area as the grade of malignancy increased. Diagnostically useful differences in the AgNOR configuration between inflammatory and neoplastic processes were found for mesothelial lesions. In general, a higher grade of malignancy correlated with an increase in the AgNOR number. This was accompanied by an increase in the total AgNOR area per nucleus, irrespective of whether the size of the individual AgNORs had changed.

Antigens, Nuclear↗
PubMed1992

[AgNOR in neurooncology].

By means of a standardized silver staining technique, nucleolar organizer region-associated proteins (AgNORs) have been demonstrated in paraffin sections of 41 astrocytomas and glioblastomas and 19 meningiomas. Computer-assisted image analysis was used to measure AgNORs together with other nuclear features. Significant differences in number and configuration of AgNORs have been found between non-anaplastic astrocytomas and anaplastic gliomata. In meningiomas, tumours with signs of increased proliferative activity and usual non-anaplastic ones could be discriminated using AgNOR data.

Astrocytoma↗
PubMed1991

A proteolytic fragment from human link protein is taken up and processed by monocytes and B cells.

Mild digestion of 125I-labelled human proteoglycan aggregates with trypsin or stromelysin produced specific peptides that were taken up rapidly by THP-1 monocytes. SDS/PAGE of undigested aggregate showed that the three components of molecular mass 48, 44 and 41 kDa, corresponding to isoforms of link protein originally present, had been converted into a single component of 41 kDa by trypsin treatment, and that fragments of 6-12 kDa were present in fractions containing the high-uptake peptide. Separate proteolysis of isolated proteoglycan monomer and link protein confirmed that the specific high-uptake fragment was derived from link protein. Uptake of the link fragment was rapid, reaching a maximum after 5 min, and specific, since it was blocked by metabolic or serine proteinase inhibitors and at 4 degrees C. After uptake the cleaved fragment was processed further, with 50% of the radiolabel being released as degraded peptides within 5 min. In contrast, accumulation of whole aggregate reached a maximum after 45 min and only 50% had been released after 2 h. Uptake of aggregate was less affected by inhibitors or at low temperature, suggesting that a separate mechanism existed for its turnover. The aggregate was transported to lysosomes after uptake, although the link fragment did not sediment with either lysosomes or plasma membranes, suggesting that it was present in the cytoplasm or in very labile vesicles. However, the mode of handling of the peptide by the cells remains unclear. The link fragment was taken up by several different monocytic and B cell lines, but not by mouse fibroblasts or peritoneal macrophages. These data suggest that a surface serine proteinase on monocytes and B cells enables them to process and take up a fragment of link protein derived by extracellular proteolysis.

B-Lymphocytes↗
PubMed1991

An embryo-specific protein of barley (Hordeum vulgare).

An immunological approach has been used to identify embryo-specific products that can be used as molecular markers of embryogenesis. Immunoadsorption of antisera to remove antigens common to embryos, meristematic cells and callus, revealed one major embryo-specific antigen, a polypeptide of 17 kDa. The antigen appeared at mid-stages of zygotic embryo formation and remained at similar levels up to six days post-germination of the seedling. The polypeptide could not be detected by protein staining, suggesting it is a non-abundant product. Appearance of the antigen could be induced by culture of zygotic embryos in vitro on abscisic acid (1 microM) or mannitol (9% mass/vol.). Cross-reactive products of near-identical molecular mass were observed in embryos of wheat, rye and oats but not distantly related cereals, nor embryos from dicotyledonous species. The timing of the appearance of the antigen was different in embryos formed from microspores during anther culture in vitro. In the cultured material, the 17-kDa polypeptide preceded the appearance of morphologically distinct embryonic structure.

Abscisic Acid↗
PubMed1991

Identification of a thioredoxin-related protein associated with plasma membranes.

A low molecular weight membrane associated sulphydryl protein was detected on a wide range of nucleated cells when [14C]-iodoacetamide was used as a probe. This protein was extracted from THP-1 monocytes, purified to homogeneity and its isoelectric point, Mr and N-terminal amino acid sequence determined. These were shown to be almost identical to the corresponding values for both human thioredoxin and a Tac interleukin-2 receptor activator, indicating that the protein may be a member of this family and function as an essential growth factor.

Amino Acid Sequence↗
PubMed1991

Continuous arteriovenous haemodiafiltration in the critically ill: influence on major nutrient balances.

The impact of continuous arteriovenous haemodiafiltration (CAVHD) on nitrogen, lipid and carbohydrate balance was studied in 9 parenterally fed critically ill patients with acute renal failure. The effects on carbohydrate delivery of varying dialysate glucose concentrations or flow rates were also investigated. The total daily nitrogen loss was a mean of 24.1 g (95% CI 20.9-27.3 g/24 h) with non-urea nitrogen losses of 7.6 g (95% CI 5.6-9.6 g/24 h). Glucose delivery was a mean 5.8 g/h with a dialysate glucose concentration of 1.5% and a flow rate of 1 l/h (95% CI 4.5-7.0 g/h). Carbohydrate delivery increased with increased dialysate glucose concentration (mean 11.4 g/h with 2.5% glucose: 95% CI 9.6-13.1 g/h; mean 14.9 g/h with a 4.25% concentration: 95% CI 10.9-19; and with increased dialysate flow rates (mean 9.6 g/h, 95% CI 6.8-12.4 g/h, using 2 l/h of 1.5% glucose). Only trace amounts of cholesterol and/or triglycerides were detected in occasional ultradiafiltrate samples. CAVHD has an important impact on nitrogen and carbohydrate balance, but not on lipid status. Knowledge of these interactions is crucial for the rational planning of nutritional strategies in the critically ill.

Acute Kidney Injury↗
PubMed1991

A modified method for the detection of nucleolar organizer regions (AgNORs).

A modified method for the detection of argyrophilic nucleolar organizer regions (AgNORs) is described. By combination of the original silver staining with a Feulgen staining at the same specimen both the AgNORs and the nuclei of the cells under study are sufficiently contrasted, so that a partial automated counting and measurement of these structures can be done using a computerized microscope image analysis system.

Animals↗
PubMed1991

Computer-assisted image analysis of nucleolar organizer regions (NORs): a pilot study of astrocytomas and glioblastomas.

Computer-assisted image analysis was used to measure nucleolar organizer regions (NORs) of 22 astrocytomas and glioblastomas. Image analysis provides reproducible information about number and size of NORs together with further karyometric data, which can be compared and processed with other patient-related data. Our study exhibits a statistical relationship between number and size of NORs and malignancy of the measured gliomas.

Astrocytoma↗