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Biomedical subjects

L Berry

Publications and source records attributed to L Berry.

At least 37 records · Page 2Linked to original sources
PubMed1998

A novel antithrombin-heparin covalent complex: antithrombotic and bleeding studies in rabbits.

Heparin has been used extensively for prophylaxis and treatment of deep vein thrombosis. However, heparin has several limitations including a short intravenous half-life, inability to inhibit clot-bound thrombin, and bleeding. We have developed a covalent antithrombin-heparin complex (ATH) that has a longer intravenous half-life and greater anticoagulant activity than heparin. The antithrombotic activity of ATH was tested in a rabbit jugular vein thrombosis treatment model. Administration of ATH caused a 17% reduction in clot weight compared with an increase of 24, 60, 172 and 135% for administration of antithrombin plus heparin, heparin, antithrombin and saline, respectively. Clot weight and fibrin accretion were both significantly lower in the ATH group than in the antithrombin plus heparin group (P < 0.05). The peak anti-factor-Xa activity was fourfold higher in the ATH group than in the antithrombin plus heparin group. Using a rabbit bleeding ear model, there was no significant difference in cumulative blood loss between ATH and antithrombin plus heparin groups, at similar plasma anti-factor-Xa levels. In conclusion, ATH has superior antithrombotic activity and similar bleeding effect compared with heparin on a mass basis. The enhanced antithrombotic activity of ATH may be a result of its increased anticoagulant activity or its longer half life, or both.

Animals↗
PubMed1997

Covalent antithrombin-heparin complexes with high anticoagulant activity. Intravenous, subcutaneous, and intratracheal administration.

Although heparin has been used clinically for prophylaxis and treatment of thrombosis, it has suffered from problems such as short duration within compartments in vivo that require long term anticoagulation. A covalent antithrombin-heparin complex has been produced with high anticoagulant activity and a long half-life relative to heparin. The product had high anti-factor Xa and antithrombin activities compared with noncovalent mixtures of antithrombin and heparin (861 and 753 units/mg versus 209 and 198 units/mg, respectively). Reaction with thrombin was rapid with bimolecular and second order rate constants of 1.3 x 10(9) M-1 s-1 and 3.1 x 10(9) M-1 s-1, respectively. The intravenous half-life of the complex in rabbits was 2.6 h as compared with 0.32 h for similar loads of heparin. Subcutaneous injection of antithrombin-heparin resulted in plasma levels (peaking at 24-30 h) that were still detectable 96 h post-injection. Given the increased lifetime in these vascular and intravascular spaces, use of the covalent complex in the lung was investigated. Activity of antithrombin-heparin instilled into rabbit lungs remained for 48 h with no detection of any complex systemically. Thus, this highly active agent has features required for pulmonary sequestration as a possible treatment for thrombotic diseases such as respiratory distress syndrome.

Animals↗
PubMed1996

Effect of antioxidants on lipopolysaccharide-stimulated induction of mangano superoxide dismutase mRNA in bovine pulmonary artery endothelial cells.

Generation of reactive oxygen species (ROS) is a common event in the pathogenesis of acute lung injury. Endothelial cells may be both a target and a source of the ROS. Exposure of bovine pulmonary endothelial cells (BPAEC) to lipopolysaccharide (LPS) has been shown to result in intracellular generation of both ROS and the antioxidant enzyme, mangano superoxide dismutase (MnSOD). The present study investigates whether alterations in intracellular oxidant state affect LPS-stimulated cytotoxicity and induction of MnSOD mRNA. BPAEC were pretreated with either the free radical scavenger, dimethylsulfoxide (DMSO), the xanthine oxidase inhibitor, allopurinol, or N-acetylcysteine (a cysteine derivate capable of increasing glutathione stores) prior to exposure to LPS (0.1 microgram/ml) for either 4, 8 or 18 hours. We found that pretreatment of BPAEC with DMSO blocked both LPS-induced cytotoxicity and induction of the MnSOD gene. Nuclear run-off experiments demonstrated that LPS-stimulated induction of the MnSOD mRNA occurred at the transcriptional level and that DMSO blocked this event. Pretreatment with allopurinol also prevented the cytotoxicity associated with LPS but, in contrast to DMSO, did not alter induction of MnSOD mRNA. N-acetylcysteine did not affect the LPS-stimulated cytotoxicity but resulted in an early and transient reduction in induction of the MnSOD gene. We conclude that LPS stimulates generation of intracellular ROS that regulate induction of the MnSOD gene at the transcriptional level further, we conclude that LPS-stimulated cytotoxicity involves both the xanthine oxidase pathway and perhaps intracellular generation of hydroxyl radicals. The difference in the protective effect between DMSO, NAC and allopurinol suggest that upregulation of the MnSOD gene does not contribute to LPS-induced cytotoxicity.

Acetylcysteine↗
PubMed1996

Patient outcomes: the link between nursing diagnoses and interventions.

The North American Nursing Diagnosis Association classification is approved for nursing diagnoses, the Nursing Intervention Classification system provides a common nursing intervention language but to date there is no complete classification for patient outcomes. An outcome classification system can be used for making effective decisions. Recognizing the need for standardized outcomes, clinical nurse specialists developed a classification of patient outcomes. These outcomes, written to fit the Nursing Intervention Classification taxonomy, incorporate Orem's Self-Care Deficit Theory.

Classification↗
PubMed1996

Role of bone marrow stromal cells in irradiation leukemogenesis.

The role of bone marrow stromal cells of the hematopoietic microenvironment in ionizing-irradiation leukemogenesis is a focus of current investigation. Evidence from recent in vitro and in vivo experiments suggests that damage by slowly proliferating cells of the hematopoietic microenvironment contributes to the sustained survival of irradiation-damaged hematopoietic progenitor cells/stem cells and can contribute to the selection and proliferation of a malignant clone. The molecular mechanism of the interaction of irradiated stromal cells with attached hematopoietic cells has been difficult to evaluate. Irradiated bone marrow stromal cell line D2XRII demonstrated altered patterns of fibronectin splicing and increased expression of several transcriptional splice variants of macrophage-colony-stimulating factor. Differential display has revealed specific radiation-induced gene transcripts which persist after irradiation of stromal cells in vitro or in vivo. In recent experiments, we demonstrated that irradiation of mouse bone marrow stromal cell line D2XRII induces release of significant levels of transforming growth factor (TGF)-beta into the tissue culture medium despite the lack of a detectable increase in TGF-beta mRNA. Since TGF-beta is known to induce reactive oxygen species (ROS), we tested how a target hematopoietic cell line, responsive to ROS by up-regulation of a transgene for an antioxidant protein, responded to cocultivation with irradiated bone marrow stromal cells. Bone marrow stromal cell line GPIa/GBL, derived from long-term bone marrow culture of a C57BL/6J-GPIa mouse, was irradiated in vitro and then cocultured with the interleukin (IL)-3-dependent hematopoietic progenitor cell line 32D cl 3, or with each of several subclonal lines expressing a transgene for human manganese superoxide dismutase (MnSOD). Cobblestone island formation, as a measure of adherence and proliferation by 32D-MnSOD clones in the presence or absence of IL-3, was increased with irradiated compared to control GPIa cells. Furthermore, using a fluorescent dye which detects ROS, hematopoietic cells cocultivated with irradiated stromal cells demonstrated higher levels of intracellular ROS than cells cocultivated and forming cobblestone islands on nonirradiated stromal cells. Since ROS are known to induce mutations in hot spots in the p53 gene, it appears worthwhile to investigate a potential mechanism for irradiated stromal cell induction of hematopoietic stem cell transformation through ROS-induced mutations. The present cell culture and molecular biology techniques provide new methods to analyze the effects of irradiated stromal cells on closely attached hematopoietic stem cells during irradiation leukemogenesis.

Animals↗
PubMed1995

alpha 2-Macroglobulin remains as important as antithrombin III for thrombin regulation in cord plasma in the presence of endothelial cell surfaces.

Infants and children rarely develop thrombotic complications compared with adults, suggesting that there are protective mechanisms in place for the young. Because endothelial cell surfaces regulate thrombin formation and inhibition, we compared thrombin regulation by human umbilical vein endothelial cell surfaces exposed to defibrinated cord and adult plasmas. After activation by either 10% activated partial thromboplastin reagent (strong activator) or coagulant phospholipids (weak activator) the following were measured: free thrombin, thrombin bound to antithrombin III (ATIII), heparin cofactor II, alpha 2-macroglobulin (alpha 2M), and prothrombin concentration. Free thrombin activity was expressed as remaining activity, after subtraction of thrombin-alpha 2M activity. After 10% activated partial thromboplastin reagent, 100% of prothrombin was consumed and significant amounts of thrombin generated by 2 min. Cord plasma generated significantly less thrombin than adult plasma, reflecting the lower initial plasma concentration of prothrombin. correspondingly, concentrations of thrombin inhibitor complexes were significantly greater in adult plasma than in cord plasma. After coagulant phospholipids, 50% of prothrombin was consumed and negligible thrombin activity measured for both adult and cord plasma. Similar amounts of thrombin inhibitor complexes were formed. ATIII was the predominant inhibitor of thrombin in adult plasma, whereas alpha 2M was as important as ATIII in cord plasma for both activators. When cord plasma concentrations of ATIII were increased to adult values, the proportion complexed to alpha 2M decreased. We conclude that on human umbilical vein endothelial cells, the capacity to generate thrombin is decreased in adult and cord plasmas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

A balance of tastes. Chefs & dietitians roundtable discussion.

The demands from foodservice customers for healthier foods that also taste good have compelled chefs & dietitians to break off their traditional separation of powers & begin forming working partnerships. These new partnerships are producing menus that strike a balance just as new--a balance between the preferences & priorities of both professions. It means a combining of two different but not incompatible perspectives that magnifies both the pleasure & the benefit of the good food they serve. In recognition of these new partnerships, FM convened the first roundtable with chefs & dietitians, all of whom are on the leading edge of this emerging trend. Excerpts of their discussion reflect striking similarities in opinion--as well as differences still to be reconciled.

Diet, Vegetarian↗
PubMed1995

Inhibition of G1-phase arrest induced by ionizing radiation in hematopoietic cells by overexpression of genes involved in the G1/S-phase transition.

D-type cyclins and cyclin-dependent kinase (cdk-4) are likely involved in regulating passage of cells through the G1 phase of the cell cycle. A decrease in the proportion of cells in G1, a relatively radiation-sensitive phase of the cell cycle, should result in increased resistance to ionizing radiation; however, the effect of such overexpression on X-ray-induced G1-phase arrest is not known. Radiation survival curves were obtained at a dose rate of either 8 cGy/min or 1 Gy/min for subclones of the IL-3-dependent hematopoietic progenitor cell line 32D cl 3 expressing transgenes for either cyclin-D1, D2 or D3 or cdk-4. We compared the results to those with overexpression of the transgene for Bcl-2, whose expression enhances radiation survival and delays apoptosis. Cells overexpressing transgenes for each D-type cyclin or Bcl-2 had an increased number of cells in S phase compared to parent line 32D cl 3; however, overexpression of cdk-4 had no effect on cell cycle distribution. Cell death resulting from withdrawal of IL-3 was not affected by overexpression of cyclins D1 and D3 but was delayed by overexpression of D2, cdk-4 or Bcl-2. Flow cytometry 24 h after 5 Gy irradiation demonstrated that overexpression of each G1-phase regulatory transgene decreased the proportion of cells at the G1/S-phase border. Western analysis revealed induction of cyclin-D protein levels by irradiation, but no change in the levels of cdk-4, p53 or p21. There was no significant change in the D0, but a significant increase in the n for cyclin-D or cdk-4 transgene-overexpressing clones at 1 Gy/min (P < 0.017). At a lower dose rate of 8 cGy/min, the n for cyclin or cdk-4-overexpressing clones was also increased (P < 0.07). Thus overexpression of cyclin-D or cdk-4 in hematopoietic cells induces detectable effects on hematopoietic cell radiation biology including a broadening of the shoulder on the radiation survival curve and a decrease in radiation-induced G1/S-phase arrest.

Animals↗
PubMed1995

Circulating dermatan sulfate and heparan sulfate/heparin proteoglycans in children undergoing liver transplantation.

The liver produces dermatan sulfate (DS), heparan sulfate (HS) and heparin glycosaminoglycans (GAG) and in the presence of hepatic disease, tissue levels of the DS GAG increase dramatically. We hypothesized that in children undergoing liver transplantation plasma levels of DS would be increased. Plasma from children undergoing liver transplantation were tested preoperative, intra operative and post operative at 24-48 h, and 1-3 weeks. Fluctuating levels of DS, HS and heparin anticoagulant activity were detected at all timepoints. The anticoagulant activity was purified and gel chromatography of the material displayed a mean Mr 110,000 D. Reductive elimination decreased the mean Mr 24,000 D indicating the activity resides on a proteoglycan (PG). The purified material was subjected to further chromatography and two peaks of anticoagulant activity resolved, compatible with at least two separate PGs, one with DS GAG chains and the additional PG(s) with HS and heparin GAG chains.

Adolescent↗
PubMed1994

Thrombin inhibition by fetal distal lung epithelium is different in fetal and adult plasma.

Intra-alveolar fibrin deposition is a cardinal feature of neonatal respiratory distress syndrome and likely contributes to short-term and long-term morbidity. Previous studies have shown that fetal distal lung epithelial cell (FDLE) surfaces express procoagulant activity when incubated with adult plasma and may therefore provide one mechanism by which fibrin is generated. However, plasma concentrations of prothrombin and thrombin inhibitors differ significantly at birth and during the first weeks of life compared with adult values. Therefore, we measured thrombin-generating capacity and inhibitor complex formation in cord and adult plasma incubated in the presence of FDLE. Although starting cord plasma concentrations of prothrombin were 43% of adult values, the amount of thrombin generated was decreased by only 21%. When cord plasma concentrations of prothrombin were selectively increased to adult values, the amount of thrombin generated surpassed adult plasma by 89%. The latter observations suggested that thrombin inhibition was impaired in cord plasma compared with adult plasma and supplementation of cord plasma with antithrombin III (ATIII) as well as prothrombin returned thrombin generation to adult levels. However, the percentage of thrombin complexed to inhibitors (59%) at the completion of the experiments was similar in cord, cord plus prothrombin, cord plus prothrombin plus ATIII, and adult plasmas. Although a higher proportion of thrombin was inhibited by alpha 2-macroglobulin (alpha 2M) in cord plasma and cord plasma plus prothrombin, this did not compensate for the decreased amount of thrombin inhibited by ATIII. When cord plasma was supplemented with ATIII as well as prothrombin, the proportions of thrombin complexed by the different inhibitors were similar to those of adult plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Identification of a key integrin-binding sequence in VCAM-1 homologous to the LDV active site in fibronectin.

The integrin adhesion receptor alpha 4 beta 1 binds two ligands, the extracellular matrix glycoprotein fibronectin and the immunoglobulin superfamily member VCAM-1. Ligand-binding sites are contained with the HepII/IIICS domain of fibronectin, and within the homologous immunoglobulin domains 1 and 4 of VCAM-1. Previous studies have shown that the binding of each ligand to alpha 4 beta 1 is mutually exclusive, suggesting that they may employ similar mechanisms to bind receptor. Fibronectin contains at least three distinct peptide sequences that are active sites for alpha 4 beta 1 binding, two homologous sequences Leu-Asp-Val-Pro (LDVP) and Ile-Asp-Ala-Pro (IDAP), and a third related to Arg-Gly-Asp (RGD). Using a combination of site-directed mutagenesis and synthetic peptide approaches in conjunction with VCAM-1-dependent cell adhesion assays, we now report the identification of a key alpha 4 beta 1-binding sequence in both domains 1 and 4 of VCAM-1 as the tetrapeptide Ile-Asp-Ser-Pro (IDSP). Mutagenesis studies also suggest that an additional sequence in domain 1, KLEK, participates in receptor binding. Since IDSP is homologous to the LDVP and IDAP fibronectin peptides, this therefore provides a molecular explanation for the promiscuity of ligand binding by alpha 4 beta 1 and has implications for the design of synthetic VCAM-1 antagonists. The extrapolation of these findings to other integrin-binding immunoglobulin ligands is also discussed.

Amino Acid Sequence↗
PubMed1994

The effects of bundling on infant temperature.

OBJECTIVE: To determine whether bundling elevates rectal and/or skin temperature of young infants. DESIGN: Randomized, prospective study stratified by age. SETTING: Clinical Studies Center at a teaching hospital in Los Angeles. PATIENTS: Sixty-four well, full-term infants (ages 11 to 95 days). INTERVENTIONS: Control infants (n = 28) were dressed in a disposable diaper and terry coveralls. Bundled infants (n = 36) were dressed as control infants, plus a cap, a receiving blanket, and a thermal blanket. All infants were monitored in an open crib (room temperature 72 degrees to 75 degrees F). Rectal and skin (anterior mid-lower leg) temperatures and infant states were measured at 5-minute intervals from time 0 to 60 minutes and at 62 and 65 minutes. RESULTS: The mean skin temperature of bundled infants increased by 2.67 degrees C/hr; mean rectal temperature increased by 0.06 degrees C/hr. The mean skin temperature of nonbundled infants increased by 1.5 degrees C/hr; mean rectal temperature decreased by less than 0.01 degree C/hr. Comparing bundled infants to nonbundled controls, there was a significant rise in skin temperature (P = .0001) but not in rectal temperature (P > .05, Wilcoxon rank sum test). The study had a power > 98% to detect a rise of .5 degrees C in rectal temperature over 60 minutes. The 95% confidence interval for the change in rectal temperature in bundled infants was -0.03 to +0.15 degrees C. CONCLUSIONS: Bundling a healthy infant in a temperate external environment causes an increase in skin temperature, but not in rectal temperature. Elevated rectal temperatures should therefore, rarely if every be attributed to bundling.

Body Temperature↗
PubMed1993

Plasma dermatan sulfate proteoglycan in a patient on chronic hemodialysis.

A 68-year-old man on chronic hemodialysis for 6 years, presented with a spontaneous psoas muscle hemorrhage. Investigations showed intermittently elevated activated partial-thromboplastin time and thrombin time. Preliminary investigations suggested a heparin-like inhibitor in the patient's plasma, but no anti-Xa activity could be detected. Investigation of the ability of patient plasma to inhibit exogenous thrombin showed that most thrombin was inhibited by heparin cofactor II, in contrast to normal plasma in which most thrombin was inhibited by antithrombin III. Treatment of plasma with glycosaminoglycan-degrading enzymes suggested the presence of dermatan sulfate (DS) in patient plasma. This was confirmed in a heparin cofactor II-dependent antithrombin assay for DS that showed anticoagulant equivalent to 2.2 +/- 0.3 micrograms/mL (mean +/- SD) of porcine mucosal DS. Of this activity, approximately 90% was sensitive to enzymes that degrade DS. The glycosaminoglycan containing fraction of plasma was isolated and subjected to gel chromatography. Anticoagulant activity eluted from Sephadex G-100 (Pharmacia, Montreal, Quebec, Canada) as two peaks with Kav of 0.10 and 0.45. After treatment with base, the Kav of the higher molecular weight species was increased to 0.55. This activity was completely sensitive to enzymes that degrade DS. Thus, the active DS was present as a proteoglycan. The lower molecular weight material was not sensitive to enzymes that degrade DS or heparan sulfate and it was active in the heparin cofactor II-dependent antithrombin assay but not in an antithrombin III-dependent antithrombin assay. This activity was not degraded by heating. Subsequently, measurement of DS activity was performed in plasmas obtained from eight other patients on hemodialysis before administration of heparin that showed that all patients had DS activity present that varied from 0.05 to 0.4 microgram/mL. No enzyme-resistant activity could be shown in these patients. In summary, a circulating anticoagulant with properties of DS is present in patients requiring hemodialysis.

Aged↗
PubMed1993

Effect of chronic FSH administration on ovarian follicular development, ovulation rate and corpora lutea formation in sheep.

This study in ewes examined the effects on ovarian function of a pulsatile regimen of ovine FSH (NIADDK-oFSH-17) administered over a 24- to 28-day period beginning on day 1 of the oestrous cycle (day 0 = oestrus). The FSH (1.66 micrograms or 5.00 micrograms) was administered i.v. over a 1-min interval once every hour throughout the treatment period. In other ewes ovine LH (NIDDK-oLH-23) was administered (10 micrograms once every 2 h) for 24-28 days together with oFSH (1.66 micrograms/h). Compared with untreated controls (n = 19 ewes), FSH alone at both doses (n = 10 ewes/dose) as well as the FSH + LH treatment (n = 10) led to significant increases in the plasma concentrations of FSH (P < 0.01), ovarian weight (P < 0.05) and ovulation rate (P < 0.01) but there was no change in the mean weight of individual corpora lutea (CL). Exogenous FSH at the high but not the low dose alone or with LH stimulated a significant overall increase in plasma inhibin concentrations (P < 0.05). The geometric mean (and 95% confidence limits) ovulation rates in the high FSH (i.e. 5.00 micrograms/h), low FSH (i.e. 1.66 micrograms/h), low FSH + LH, and control treatment groups were 15.3 (9.3, 24.8), 3.7 (2.1, 6.0), 3.7 (2.5, 5.8) and 1.4 (1.2, 1.7) respectively. The FSH or FSH + LH treatments did not alter the total numbers of antral follicles (> or = 1 mm diameter). However, the high but not the low FSH or low FSH + LH treatment led to significant increases in the mean numbers of large follicles (i.e. > 4.5 mm diameter; P < 0.01) and a higher proportion of non-atretic antral follicles. Highly significant linear relationships were found between the mean plasma concentrations of FSH or inhibin and the ovulation rate (FSH: r = 0.74, P < 0.0001; inhibin: r = 0.93, P < 0.0001). Highly significant linear relationships were also found between the plasma concentrations of FSH or inhibin and the number of large follicles (i.e. > 4.5 mm diameter; FSH, r = 0.78, P < 0.0001; inhibin, r = 0.80, P < 0.0001) and between the plasma concentrations of inhibin and the number of granulosa cells in large follicles (r = 0.78, P < 0.0001). After the high FSH but not the low FSH treatment there were significant increases in both FSH- and LH-induced responsiveness in granulosa cells with respect to cyclic AMP synthesis in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Microfibrillar assemblies of foetal bovine skin. Developmental expression and relative abundance of type VI collagen and fibrillin.

Intact type VI collagen microfibrils and fibrillin-containing microfibrils were isolated from foetal bovine skin and investigated immunochemically and ultrastructurally. Substantial variations were detected in the abundance and macromolecular assembly of these structures at progressive stages of gestation. Microfibrils of collagen VI were increasingly abundant in skin through foetal development from late first trimester to term. The pattern of expression of fibrillin-containing microfibrils in foetal skin differed from that of collagen VI. Fibrillin-containing microfibrils were particularly sparse in first trimester skin, and present only as short assemblies. However, by early second trimester there had been a sharp increase in the abundance and length of these fibrillin-containing microfibrils. These observations are consistent with early second trimester being a key phase of fibrillin assembly. In the third trimester, fibrillin-containing microfibrils were frequently isolated in association with amorphous material. This information on the pattern of expression and assembly of collagen VI microfibrils and fibrillin-containing microfibrils in foetal skin implies temporally and functionally distinct contributions of these two components to the establishment of the fibrous dermal matrix.

Animals↗
PubMed1992

Properties of redox-inactivated bleomycins. In vitro DNA damage and inhibition of Ehrlich cell proliferation.

Blenoxane, bleomycin A2, bleomycin B2, and demethyl bleomycin A2 and products of their reactions with Fe2+ and oxygen were used to explore the relationship between their capacity to carry out in vitro DNA strand scission and their growth inhibitory activity against Ehrlich cells. Reaction of Fe2+, bleomycin and O2 in the absence of DNA decreased the subsequent effectiveness of various bleomycin congeners to degrade DNA in the presence of Fe2+ and oxygen. In comparison with controls, this loss of strand scission activity was not paralleled by equivalent decreases in growth inhibition. Demethyl bleomycin A2 retained full biological activity relative to bleomycin A2, despite being only 30% as effective as bleomycin A2 in its ability to cleave DNA in vitro. Prior reaction of bleomycins with Fe2+ did not alter their capacity to reduce oxygen or affect their ability to generate the activated intermediate which, for native bleomycin structures, is competent to cleave DNA in vitro.

Animals↗
PubMed1992

Microfibrillar components in dental pulp: presence of both type VI collagen- and fibrillin-containing microfibrils.

Microfibrillar elements were isolated from developing and formed bovine dental pulp by a procedure involving bacterial collagenase tissue digestion and chromatography on Sepharose CL-2B. Two microfibrillar assemblies could be demonstrated. Type VI collagen microfibrils with a characteristic periodicity of about 100 nm appeared as long, thin, flexible filaments. In a number of cases these structures aggregated by lateral association. Microfibrils of 10-14 nm dia were identified as containing fibrillin on the basis of their distinctive, periodic, beaded morphology. In addition to long, single strands there were instances of chains coalescing to give amorphous aggregates. No differences in the type of microfibrillar assemblies were evident between developing and formed pulp, although fibrillin-containing microfibrils were more abundant in formed pulp.

Actin Cytoskeleton↗