Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RADIOAUTOGRAPHY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1987

3H-mannose utilization by fibroblasts of the periodontal ligament.

The synthesis, intracellular translocation, and secretion of mannose-containing glycoproteins(s) by periodontal ligament fibroblasts have been investigated by means of electron microscopic radioautography. Tritiated mannose was administered to young mice via jugular vein, and radioautographs were prepared at 5, 10, 20, and 35 minutes, 4 and 8 hours after injection. Analysis of electron microscopic radioautographs revealed a maximum labeling (94%) with 3H-mannose of the rough endoplasmic reticulum at 5 minutes. Labeling of the Golgi components started to increase from 10 minutes (14%) and reached a maximum level at 20 minutes (31.2%). At 35 minutes, secretion granules, dense bodies, profiles of intracellular collagen, and the cell surface were labeled. At 8 hours, most labelling (79.2%) was extracellular, and associated either with the collagenous matrix (43.7%) or the cell surface (35.5%). Cytoplasmic vesicles containing dense materials around collagen fibrils were also labeled at 8 hours. It is concluded that mannose is directly incorporated into the rough endoplasmic reticulum (RER), and that mannose-containing glycoprotein(s) are packaged in the Golgi apparatus into secretory granules. Mannose-containing glycoprotein(s) become distributed on the periodontal ligament (PDL) fibroblast cell surface, cytoplasmic dense bodies, and the extracellular matrix.

Animals↗
PubMed1987

Demonstration of expanding cell populations in mouse pancreatic acini and islets.

The acinar and islet cells of the adult mouse pancreas were examined by radioautography after continuous infusion of 3H-thymidine, for periods varying from 1 to 60 days, to determine whether they behaved like renewing or expanding cell populations. The labeling of both cell types increased with the duration of the continuous infusion and reached 2.22% and 12.0%, respectively, after 60 days. The rate of acinar and islet cell labeling was estimated from the regression line of the labeling index versus time and given as 0.039% and 0.20% cells per day, respectively. The rate of cell labeling was relatively low in these acinar and islet cells in comparison to the relatively high rate in duct cells. Occasionally, acinar cell labeling was not uniform, showing high labeling in the outer peripheral region of a lobe and at the periphery of the islets. Both acinar and islet cells increased in number in the adult, and at a rate indicating they are expanding cell populations. Their doubling times were estimated as 2,564 days (7.0 years) and 500 days (1.3 years), respectively. Duct epithelial cell populations were dividing at a rate indicating that they are renewing cell populations.

Animals↗
PubMed1987

Specific binding sites for transferrin on ameloblasts of the enamel maturation zone in the rat incisor.

During enamel maturation in rodents, an iron-containing pigment is deposited into the surface layer of the enamel. Maturation zone ameloblasts presumably are responsible for this deposition. The presence of large amounts of ferritin in the cytoplasm of these cells suggests that they receive iron, presumably from circulating transferrin. An in vivo radioautographic binding assay using iodinated transferrin was used to determine if indeed maturation ameloblasts possess transferrin receptors at their cell surfaces. Experimental rats received systemic injections of labeled transferrin while control rats received injections of labeled transferrin plus a large excess of unlabeled transferrin in order to compete with the labeled transferrin for available specific receptors. Light microscope radioautography showed that ruffle-ended ameloblasts (RAs) of the enamel maturation zone had a high density of specific receptors for transferrin relative to smooth-ended ameloblasts (SAs). Electron microscopy and energy-dispersive X-ray spectroscopy confirmed the presence of ferritin and iron, respectively, within these cells. It is postulated that the iron responsible for enamel pigmentation is transported by transferrin to maturation ameloblasts and is bound to specific transferrin receptors found mostly on RAs and that the modulation of these cells into SAs results in a loss of most of these receptors.

Ameloblasts↗
PubMed1988

Lifetime of the osteoblast in mouse periodontium.

The kinetics of osteoblasts and osteocytes on appositional and resorptive surfaces of mouse alveolar bone were examined using 3H-thymidine and 3H-proline radioautography. Our results show that the osteoblasts at the appositional surface of the mouse periodontium are recruited from a progenitor population in the G1 phase of the cell cycle that goes through a single S-phase before differentiating into osteoblasts and that the active lifetime of the osteoblast on the periodontal surface is approximately 20 days. The lifetime of the osteoblasts on periosteal and endosteal surfaces is 10 days. The active lifetime of an osteoblast appears to be independent of the amount of matrix produced.

Alveolar Process↗
PubMed1988

Radioautographic demonstration of receptors for epidermal growth factor in various cells of the oral cavity.

Mouse iodinated epidermal growth factor (EGF) was localized by light and electron microscopic radioautography in basal cells of oral epithelium, papillary cells of the enamel organ, periodontal ligament fibroblasts, preodontoblast precursor cells, and preosteoblasts of the alveolar bone of 13-day-old Sprague-Dawley rats. The specificity of binding in these cells was suggested by an observed reduction of about 90% in the labeling when excess unlabeled EGF was injected along with the 125I-EGF. In contrast, fully differentiated cells, such as ameloblasts, odontoblasts, and osteoblasts, were only poorly labeled. Quantitative analysis of the light microscopic radioautographs revealed that the papillary cells had the highest level of labeling (5.5 grains per 100 micron 2 of cell area). The significance of the rather high labeling of the preosteoblasts of the alveolar bone and the fibroblasts of the periodontal ligament is unknown. However, the well-known effect of EGF in producing precocious eruption of teeth may be a consequence of an effect on these two cell types.

Animals↗
PubMed1989

Banding patterns in rat incisor enamel stained by histochemical complexing methods for calcium.

A characteristic banding pattern can be visualized at the surface of the rat incisor in the maturation zone of amelogenesis by staining with glyoxal bis(2-hydroxyanil) (GBHA). Other banding patterns can be obtained with certain histological and fluorochrome stains and by radioautography following 45Ca injection. In this study, several histochemical reagents known to complex with different states of calcium were used to stain the surface of enamel. Rat incisors were quickly dissected and immediately immersed in solutions containing the following calcium-binding reagents: arsenazo III, calmagite, murexide, N,N-naphthaloylhydroxylamine, and calcein. Routinely, one contralateral lower incisor from each pair was counterstained with GBHA in order to relate each of the staining patterns to the banded distribution of maturation ameloblasts that is reflected by the characteristic GBHA staining pattern in the enamel. Each of the reagents used in this study demonstrated a staining pattern consisting of a series of broad bands running transversely and obliquely across the enamel. In all cases, the dyes stained predominantly that enamel associated with ruffle-ended ameloblasts, i.e. enamel left unstained by GBHA. Some of the reagents also stained enamel in the secretion zone. The appearance and distribution of the staining patterns reflect the banded distribution of maturation ameloblasts and appear to be controlled on a time scale related to the rapid modulation of these cells.

Animals↗
PubMed1989

Comparison of 3H-galactose and 3H-glucose as precursors of hepatic glycogen in control-fed rats.

Labeling of hepatic glycogen derived from 3H-galactose and 3H-glucose was compared shortly after intravenous injection in control-fed rats. The rats were allowed to accumulate 5-8% glycogen prior to receiving label. Fifteen minutes to 2 hours after labeling, liver was excised and processed for routine light (LM) and electron microscopic (EM) radioautography (RAG) or biochemical analysis. After injection of 3H-galactose, LM-RAGs revealed that the percentage of heavily labeled hepatocytes increased from 37% after 15 minutes to 68% after 1 hour but showed no further increase after 2 hours. alpha-Amylase treatment removed most glycogen and incorporated label; thus few silver grains were observed, indicating little incorporation of label except into glycogen. EM-RAGs demonstrated that most label occurred where glycogen was located. Biochemical analysis showed initially a high blood level of label that rapidly plateaued at a reduced level by 5 minutes. Concomitantly, glycogen labeling determined by liquid scintillation counting reflected the increases observed in the RAGs. After injection of 3H-glucose, LM-RAGs revealed that only 12% of the hepatocytes were heavily labeled at 1 hour and 20% at 2 hours. In tissue treated with alpha-amylase, glycogen was depleted and label was close to background level at each interval observed. EM-RAGs showed most grains associated with glycogen deposits. Biochemically, blood levels of label persisted at a high level for 30 minutes and tissue levels increased slowly over the 2-hour period. This study shows that incorporation from 3H-galactose was more rapid than incorporation of 3H-glucose; however, label derived from both carbohydrates appeared to be incorporated mainly into glycogen.

Animals↗
PubMed1989

Synthesis and secretion of collagen by cells of connective tissue, bone, and dentin.

The production of type I collagen by fibroblasts, odontoblasts, and osteoblasts is reviewed on the basis of results obtained by electron microscopy, 3H-proline radioautography, and immunostaining for type I procollagen. In the three cell types, the precursors of type I collagen are processed along the rough endoplasmic reticulum (rER)-Golgi-secretory granule pathway in the same manner as secretory proteins, but the available evidence suggests a few special features: 1) From the rER site of synthesis, the initial collagen precursors, known as pro-alpha chains, are transported to the Golgi apparatus within tubular structures, referred to as intermediate tubules, rather than within vesicles. 2) The pro-alpha chains coil into a triple helix within spherical distensions present along the saccules on the cis side of Golgi stacks. 3) The resulting procollagens are fairly rigid and form bundles that cause spherical distensions to lengthen into cylindrical ones, whereas by an unknown mechanism these distensions become part of the saccules on the trans-side of Golgi stacks. 4) The procollagen-containing cylindrical distensions are released from trans-saccules to become secretory granules, and some procollagen material finds its way into lysosomes. 5) The secretory granules release their procollagen content by exocytosis at the cell surface. 6) The released procollagen is transformed into collagen before or, more probably, after associating with the surface of a collagen fibril.

Animals↗
PubMed1989

Biosynthesis and secretion of enamel proteins in the rat incisor.

The synthesis and secretion of enamel proteins (EPs) in rat incisors was examined using cytochemical and biochemical methods. Radioautography after injection of 3H-methionine showed that ameloblasts in the presecretory, secretory, and maturation stages of amelogenesis actively synthesized and secreted proteins. Immunocytochemistry with an antibody to mouse amelogenins revealed the presence of EPs in the protein synthetic and secretory organelles of these cells at all three stages. Labeling was also found in elements of the endosomal/lysosomal compartment. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining of proteins extracted from enamel and enamel organ showed several protein bands. However, transfer to nitrocellulose paper and immunoblotting revealed that most of the proteins recognized by the antibody were situated between approximately 14 and 32 kDa. EPs were further characterized by using lectins to examine their carbohydrate content. Lectin-gold cytochemistry on sections showed the binding of wheat germ agglutinin and Helix pomatia lectin to secretory stage enamel. Lectin blotting indicated that the amelogenins were heterogeneously glycosylated and contained the sugars N-acetyl-glucosamine/N-acetyl-neuraminic acid and N-acetyl-D-galactosamine. Fluorography at 6 and 10 min and 1 h after injection of 35S-methionine revealed four labeled bands in the main amelogenin group near 22, 28, 30, and 32 kDa. A short-lived protein of approximately 58 kDa was also observed primarily in cells. The appearance of labeled proteins in enamel was paralleled by their disappearance from cells and the intensity of the radiolabeled protein bands, both, in enamel and in cells, decreased towards the maturation stage. These data are consistent with the concept that ameloblasts produce multiple amelogenins throughout amelogenesis.

Ameloblasts↗
PubMed1989

Degradation and loss of matrix proteins from developing enamel.

The pattern and timing of the breakdown and loss of matrix proteins were studied in developing rat incisor enamel using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fluorography, radioautography, and in vitro incubations of proteins isolated from freshly dissected, crushed pieces of enamel. For biochemical studies, the technique of Robinson et al. (1974, 1977, 1983) was used to transect the enamel organ and enamel into a series of strips at 1 mm intervals along the length of the tooth. The proteins in each strip were extracted and either quantified by Lowry analysis or applied to 12% slab (enamel) or 5-15% continuous gradient (enamel organ) SDS-polyacrylamide gels and separated by electrophoresis. The biochemical studies indicated that the amount of protein contained within an enamel strip increased gradually by volume across the secretory stage, reached a peak early during the maturation stage, and then declined rapidly thereafter. The distribution of enamel proteins on SDS-polyacrylamide gels changed markedly throughout this period. These changes included increases and decreases in the intensity of staining of proteins at certain molecular weights (e.g., 18 kDa) and the appearance and disappearance of some proteins not seen clearly near the start of the secretory stage of amelogenesis (e.g., 32 and 10 kDa). Labeling studies with 35S-methionine suggested that the "stacked" arrangement of proteins typical of forming enamel (secretory stage) actually represented a very dynamic association of proteins, with new ones being added at the top of the stack and then breaking down with time to become those seen at lower molecular weights. Across the secretory stage, new proteins were always added to the top of the stack, but during early maturation this activity slowed dramatically, allowing the breakdown of aging proteins to be visualized more clearly. Radioautographic studies with 3H-methionine indicated that the breakdown of newly secreted proteins also was correlated with a movement of label from the site of secretion into deeper, previously unlabeled, areas of forming enamel. In vitro studies revealed that the rate and degree of breakdown of enamel proteins varied markedly, depending on the stage of amelogenesis from which the proteins were extracted. Secretory stage enamel proteins showed slow in vitro degradation with accumulation of proteins near 18 kDa. Early maturation stage enamel proteins showed more rapid breakdown with little accumulation of proteins near 18 kDa, whereas late maturation stage enamel proteins showed complete degradation by 2 days of incubation in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Ameloblasts↗
PubMed1990

Migration of fetal intestinal intervillous cells in neonatal mice.

The migration of intestinal intervillous epithelial cells labeled in the fetus was followed in neonatal mice. At 17 days of gestation, a first group of pregnant mice received three intraperitoneal injections of 3H-thymidine (150 microCi/injection) administered at 30 min intervals. Two mothers were sacrificed 3 hours after the first injection. Mice from different litters were also sacrificed on days 0, 2, 4, 8, 12, 14, and 16 after birth. A second group of pregnant mice was injected at 18 1/2 days of gestation and offspring were sacrificed on days 6, 8, 10, 12, 14, and 16 after birth. Segments of duodenum and ileum were fixed in glutaraldehyde, postfixed in osmium tetroxide, dehydrated, and embedded in Epon. Sections were stained with aldehyde fuchsin and processed for radioautography. By following the leading front and trailing edge of labeled cells in the longest villi of the duodenum and ileum, we observed that 1) extrusion zones become active immediately after birth and 2) the longest villi do not elongate until 10 days after birth in the duodenum and 14 days in the ileum, that is, when all labeled epithelial cells originally present in the fetus have been extruded. Moreover, by measuring the distance between the internal limit of the inner circular layer of smooth muscle and the intervillous epithelium at 17 days of gestation (12.95 +/- 1.18 microns) or the bottom of the crypts at day 3 (14.81 +/- 0.91 microns), we propose that crypts do not develop as downgrowths: rather the intervillous epithelium is reshaped and the crypt-villus junction moves upward, away from the muscularis externa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Development of esophageal epithelium in the fetal and neonatal mouse.

Development of the fetal mouse esophageal epithelium was followed using light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and radioautography. At 15 days of gestation in the cervical (C), mediastinal (M), and abdominal (A) segments of the esophagus, the epithelium was two or three cells thick, and only cells located in the basal (germinal) layer incorporated tritiated thymidine. Ciliated cells were sparse in all three segments. At 17 days of gestation, longitudinal mesenchymal ridges became more differentiated in the distal segment. Labeling indices were lower than at preceding stages in each segment. Ciliated cells had increased in number and appeared to be evenly distributed along the whole esophagus. In periodic acid-Schiff (PAS)-stained sections, an increasing proximodistal distribution of glycogen stores was observed, with greatest concentrations found in segment A. At 18 days of gestation, labeling indices were comparable in segments C and M (11.7% +/- 2.9% and 12.8% +/- 1.9%, respectively) but remained higher in segment A (17.9% +/- 2.0%). Ciliated cells were still present. At this stage, transverse circular furrows and ridges started to appear. They increased in number at 4 days after birth and were very closely distributed in the adult. In longitudinal sections, these ridges corresponded to projections of stratum granulosum and of the overlying stratum corneum. After birth, ciliated cells desquamated rapidly but some patches were still present at 4 days. At 8 days, the esophageal epithelium was not yet keratinized.

Animals↗
PubMed1991

Occurrence of epidermal growth factor-binding sites during differentiation of cementoblasts and periodontal ligament fibroblasts of the young rat: a light and electron microscopic radioautographic study.

Occurrence of epidermal growth factor (EGF)-binding sites during differentiation of cementoblasts and periodontal ligament (PDL) fibroblasts was investigated using radioautography after I. V. injection of 125I-EGF to 14-day-old rats. During differentiation of cementoblasts, a very low level of EGF-binding sites was present on the mesenchymal cells in dental follicle proper, precementoblasts, and cementoblasts. On the other hand, during differentiation of PDL fibroblasts, numerous EGF-binding sites were observed on the undifferentiated paravascular cells and on the perifollicular mesenchymes representing the major source of PDL fibroblast precursor cells. Also heavy labeling was observed throughout their differentiation to PDL fibroblasts, as well as during full synthetic activity as mature cells. Quantitative analysis of the light microscopic radioautographs revealed that these cells demonstrated approximately 4 grains per 100 microns 2 of cell area. These results suggest that EGF plays an important role in differentiation of PDL fibroblasts, but not in that of cementoblasts. Furthermore, the well-known in vivo effect of EGF in producing precocious eruption of teeth may be a consequence of a more extensive effect of EGF throughout differentiation of PDL fibroblasts as well as during full synthetic activity as mature cells.

Animals↗
PubMed1991

Thecal and interstitial cells in polycystic ovaries (PCO) in the rat.

Two different types of experimentally-induced polycystic ovaries (PCO) have been examined. A macrocystic ovarian condition is induced by estradiol valerate (EV) injection, whereas a microcystic ovarian condition is engendered with subcutaneous estradiol implants. In both of these models thecal and secondary interstitial cells were characterized using three functionally significant indices. Expression of alkaline phosphatase was evaluated immunohistochemically, hCG/LH-binding capacity was assessed by means of EM radioautography, and the size and percent cytoplasmic area of intracytoplasmic lipid were determined, in the same cells, by morphometry. In both types of ovary, thecal cells of healthy and atretic follicles stained heavily for alkaline phosphatase whereas cystic theca exhibited little or no staining. Intermittent faintly stained patches of secondary interstitial cells, as well as intensely stained spheroidal cell clusters, were most numerous in the microcystic ovary and occurred less frequently in the macrocystic ovary. Cystic thecal cells in both conditions exhibited large lipid droplets and minimal hCG binding. Lipid droplet area was minimal and hCG binding maximal in secondary interstitial cells of both types of ovary. It is concluded that specific clusters of secondary interstitial cells are important steroidogenic elements in PCO, whereas cystic theca is relatively inert.

Alkaline Phosphatase↗
PubMed1992

Development and cytodifferentiation of peritubular myoid cells in the rat testis.

The cytodifferentiation of peritubular myoid cells was studied in developing rats from fetal day 18 through approachment of puberty. The parameters taken into consideration were 1) the presence of desmin, a component of intermediate filaments in contractile cells; 2) the expression of alkaline phosphatase, a cell surface enzyme present in no other cell type of the seminiferous tubule; 3) the expression of the smooth muscle specific isoform of alpha-actin, a marker of terminal differentiation in smooth muscle cells; 4) cell proliferation rate, evaluated in radioautography as labeling index after incorporation of 3H-thymidine in short-term organ culture; and 5) cytoarchitectural changes detected with scanning electron microscopy. By means of immunofluorescence and cytochemistry it was observed that the three markers are expressed early during life, long before the onset of the first spermatogenic wave; in particular desmin is already present in fetal samples and alkaline phosphatase activity appears a few days after birth, whereas alpha-smooth muscle isoactin is first detected around birth. As for myoid cell replication, the high prenatal labeling index was found to drop soon after birth and to further slow down during the first month of postnatal life, suggesting that myoid cell proliferation is not a major factor in peritubular expansion. SEM examination of developing peritubulum has shown that, when approaching puberty, the myoid cell undergoes a dramatic change in cytoarchitecture, consisting in extreme flattening and cytoplasmic expansion resulting in an apparent increase in peritubular surface.

Actins↗
PubMed1993

Dynamics of epithelial cells in the corpus of the mouse stomach. II. Outward migration of pit cells.

The pit cells (or surface mucous cells) present along pit walls and gastric surface have been investigated by electron microscopy and radioautography after a pulse or continuous infusion of 3H-thymidine. For these studies, the pit region has been subdivided into four segments: three of equal length along the pit wall, respectively named low pit, mid pit and high pit, and a last one at the surface named pit top. The pit region includes an average of 37 pit cells, characterized by dense mucous granules accumulated along the apical membrane in an organelle-free zone referred to as ectoplasm. Continuous 3H-thymidine infusion reveals that pit cells come from pre-pit cells, which are believed to arise in the isthmus region from the undifferentiated granule-free cells through a pre-pit cell precursor stage. The pre-pit cells, characterized by the presence of a few mucous secretory granules scattered in the cytoplasm, migrate outward (i.e., in the direction of the gastric lumen). When the secretory granules line up along the apical membrane in the ectoplasm, the pre-pit cell becomes pit cell. It is estimated that 87% of pit cells differentiate from pre-pit cells, while the remaining 13% come from their own mitoses. Observations at successive times after a 3H-thymidine pulse demonstrate that pit cells, like pre-pit cells, migrate toward the gastric surface where they are eventually lost. The continuous 3H-thymidine infusion results indicate that this migration takes 3.1 days on the average. Cells spend almost a day in each pit wall segment. In the low pit segment, cells produce more and larger mucous secretory granules than do pre-pit cells. In the mid and high pit segments, the number and size of the granules generally keeps on increasing, thus indicating that mucous differentiation is progressing. The secretory granules arising in the Golgi apparatus of pit wall cells are mostly spherical; they retain this shape during the few minutes taken to cross the cytoplasm and enter the apical ectoplasm. They spend about an hour in the ectoplasm, where they change to an ovoid shape as they approach the apical membrane to finally release their content by exocytosis. The mucous differentiation along the pit wall is associated with a progressive decline in the organelles: nucleoli and mitochondria decrease in size while the amount of free ribosomes diminishes. When pit cells reach the free surface, they produce fewer, smaller secretory granules and at a lower rate than in mid and high pit.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Differentiation of periodontal ligament fibroblasts into osteoblasts during socket healing after tooth extraction in the rat.

BACKGROUND: The entire socket after tooth extraction is filled with new bone formed by osteoblasts (Obs), but the origin of these Obs remains unknown. Thus, the proliferation and migration of paravascular and endosteal fibroblastic cells and periodontal ligament (PDL) fibroblasts (Fbs) and their differentiation into Obs during socket healing after extraction of the first maxillary molars of the rat were investigated. METHODS: The proliferative activity and migration of these cells in the sockets after tooth extraction were studied using radioautography and immunohistochemistry after injection of 3H-thymidine and 5-bromo-2'-deoxyuridine (BrdU), respectively. Their morphological changes during differentiation was investigated by transmission electron microscopy. RESULTS: One day after tooth extraction, PDL Fbs were the major cell type in the PDL remnant of the socket. Proliferation was low (labeling index (LI) = approximately 2%) until 16 h after tooth extraction but dramatically increased to a maximum level 1 day postextraction (LI = 23%). Between 1 and 2 days, numerous PDL Fbs in the PDL remnant actively migrated into the coagulum and continued to proliferate. On the basis of the high proliferative activity and small number of cellular organelles responsible for procollagen synthesis, these cells appear immature. At 3 days, Fbs contained more cellular organelles and deposited more collagen fibers as they replaced the coagulum with dense connective tissue and the LI declined. At 4 and 5 days, some of the Fbs began to differentiate into Obs, and the proliferation of Fbs dramatically decreased to baseline values. The migration of PDL Fbs and their differentiation into Obs were investigated by labeling with 3H-thymidine or BrdU 1 day after tooth extraction. Heavily labeled Fbs were observed in the PDL remnant at 1 day, in the coagulum at 2 days, and in the dense connective tissue at 3 days. Labeled Obs associated with new bone were seen 4 days after injection. Endosteal and paravascular Fbs also proliferated, but at a lower level and at later time periods than the PDL Fbs. Surprisingly, endosteal and paravascular Fbs contributed only a small population of Fbs to socket healing. CONCLUSIONS: These results indicate that PDL Fbs after tooth extraction actively proliferative, migrate into the coagulum, form dense connective tissue, and differentiate into Obs which form new bone during socket healing.

Animals↗
PubMed1989

A critical examination of the reaction of pyridoxal 5-phosphate with human hemoglobin Ao.

Pyridoxylated normal adult human hemoglobin (HbAo) has been prepared using both oxygenated and deoxygenated HbAo at pH 6.8 and room temperature without the addition of Tris to produce a mixture with P50 of 30 +/- 2 torr and a Hill coefficient of 2.3 +/- 0.1 similar to that of the isolated adult human hemoglobin from the red blood cell. Reduction of the pyridoxylated HbAo in the oxygen-ligated form by sodium borohydride gives unacceptable levels of methemoglobin (i.e., greater than 10%). Excessive foaming and methemoglobin formation can be partially avoided using deoxyHbAo. Reduction with sodium cyanoborohydride is much gentler and gives solutions with less than 5% methemoglobin. Both reducing agents give products with multiple components as shown by analytical chromatography. Radioautography on the isoelectric focusing gels of HbAo treated with 14C pyridoxal 5-phosphate (PLP) shows three major bands for the cyanoborohydride-reduced derivatives and a much more complex mixture of labeled molecules after the sodium borohydride reduction. When pyridoxylated hemoglobin is prepared without reduction, the preparation, after passage through a mixed-bed resin, contains 0.4 equivalents of PLP per heme, and has a P50 of 30 +/- 2 torr and an n value of 2.3 similar to the values found after reduction. Upon anion exchange resin chromatography, the PLP is removed, indicating that the reaction forms a reversible Schiff base. On standing at 4 degrees C for one month, this preparation produces a mixture of HbAo and pyridoxylated HbAo with the original P50. Methemoglobin increased to 3% during this incubation. After four months in the cold, the yield of a single chromatographic species is 70% with 20% methemoglobin. This fraction appears to be stable and can be passed through an anion exchange column without release of the PLP. Separation of the individual chains by reverse-phase chromatography indicates that the addition of PLP to HbAo is directed solely to the beta-chains. This is also the case for the cyanoborohydride reduced derivatives. When NaBH4 is used for the reduction, radioactively labeled PLP is found on both the alpha- and beta-chains.

Hemoglobin A↗