Physics of Nuclei: Key Role of an Emergent Symmetry.

We show through first-principles nuclear structure calculations that the special nature of the strong nuclear force determines highly regular patterns heretofore unrecognized in nuclei that can be tied to an emergent approximate symmetry. This symmetry is ubiquitous and mathematically tracks with a symplectic symmetry group. This, in turn, has important implications for understanding the physics of nuclei: we find that nuclei are made of only a few equilibrium shapes, deformed or not, with associated vibrations and rotations. It also opens the path for ab initio large-scale modeling of open-shell intermediate-mass nuclei without the need for renormalized interactions and effective charges.

Biphasic effect of calcitonin on tartrate-resistant acid phosphatase activity in isolated rat osteoclasts.

Tartrate-resistant acid phosphatase (TRAP) has been implicated as being involved in osteoclastic bone resorption, and calcitonin (CT) is known to inhibit the resorptive process. This study investigates the kinetics of CT action on TRAP activity in isolated rat osteoclasts using both biochemical and quantitative cytochemical methods. The latter technique has been developed to detect very small changes in intracellular TRAP activity at the single-cell level. The biochemical study showed that 10(-9) M salmon CT (sCT) decreased TRAP activity in medium throughout the experimental period; TRAP activity in the cells was increased during the first 2 h but subsequently declined and was decreased to a significant level at 6 h. TRAP activity in sCT-treated osteoclasts measured by the cytochemical method showed significant increases within the first hour. This response was dose dependent between 10(-16) and 10(-11) M sCT with EC50 at 8 X 10(-14) M. After 1 h, the initial increase in intracellular TRAP activity in CT-treated osteoclasts was followed by a decline to below control levels, reaching statistical significance at 9 h. Treatment with forskolin (10(-5) M) showed a similar trend, suggesting that this response is mediated by cyclic AMP-regulated phosphorylation events. From these results, we conclude that CT has two actions on TRAP in isolated rat osteoclasts: the first to inhibit its release, the second to inhibit its synthesis and/or increase its degradation.

A carboxyl-terminal peptide from the parathyroid hormone-related protein inhibits bone resorption by osteoclasts.

PTH-related protein (PTHrP) interacts, via its amino-terminal 34 residues, with PTH receptors on osteoblasts to stimulate osteoclastic bone resorption indirectly. We now report that mature hPTHrP-(1-141) (EC50, approximately 10(-11) M) and a carboxyl-terminal fragment, PTHrP-(107-139) (EC50, approximately 10(-15) M), are potent inhibitors of resorption in an isolated rat osteoclast bone resorption assay, whereas hPTHrP-(1-108) and hPTHrP-(1-34) are inactive in this respect. PTHrP-(107-139) also inhibits resorption in a rat long bone organ culture system and reduces osteoclast spreading. PTHrP-(107-139) does not act on osteoclasts via a cAMP signal transduction mechanism, but its effects may be mediated by protein kinase-C. This previously unrecognized action of PTHrP, to inhibit osteoclastic bone resorption directly, indicates that PTHrP may be a precursor of multiple biologically active peptides with differing physiological functions.

Effects of a fluorinated bisphosphonate on bone remodeling in vivo.

A new fluorinated bisphosphonate, difluoromethylene bisphosphonate (F2MBP), was studied for its effects on physiologic bone remodeling in the actively growing rat tibia. Young male Sprague-Dawley rats were given daily subcutaneous injections of either saline (control) or 30 mg/kg per day of F2MBP, dichloromethylene bisphosphonate (Cl2MBP), or 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) for 30 days. Microradiographs of the epiphysealmetaphyseal region of tibiae from animals treated with either F2MBP or Cl2MBP demonstrated increased radiodensity but, unlike those treated with HEBP, without an increase in the width of the epiphyseal growth plate. Quantitative analyses of these microradiographs showed that there was an increase of calcified tissue in the metaphyseal region in all diphosphonate groups when compared with controls. However, the HEBP-treated animals exhibited significantly less increase than either F2MBP-treated or Cl2MBP-treated rats. In addition, the total area of calcified tissue in the diaphyseal transverse sections was greater in the F2MBP-treated animals than in controls. Elemental calcium, phosphorus, and fluorine, as detected by the electron probe, also increased in the metaphyseal region of the F2MBP-treated animals, but no significant differences in the calcium: phosphorous ratio were found among the control, F2MBP, and Cl2MBP treatment groups, indicating no alterations in the chemical composition of bone. The greater amount of fluorine in the tibiae of F2MBP-treated animals reflected the presence of the F2MBP molecule. Thus, this study has demonstrated that this new fluorinated bisphosphonate, like Cl2MBP, inhibits physiologic bone remodeling without disturbing mineralization. Furthermore, the presence of fluorine in F2MBP allows the precise localization of the incorporation of the bisphosphonate within the bone.

Uptake of a fluorinated bisphosphonate by cultured bones.

The uptake of bisphosphonates into bone was studied using 19-day-old fetal rat bones cultured with a new fluorinated bisphosphonate, difluoromethylidene bisphosphonate (F2MBP). F2MBP uptake was assessed by determining the weight percent of fluoride using electron probe microanalysis. By 30 min the weight percent of fluoride was significantly greater in the F2MBP-treated bones than in controls and continually increased throughout the duration of the experiment to reach a fluoride concentration 6-fold greater than controls after 120 h of incubation. When the peripheral cortical bone was analyzed separately from the interior trabecular bone in the F2MBP-treated bones, the fluoride concentration in the periphery increased until 24 h and then remained somewhat constant, while the interior, which is more actively remodeling, showed a continual increase. The uptake of F2MBP during the 1 to 6 h time intervals demonstrated no differences between vital and devitalized bone and, thus, is not cell-mediated. Because analysis of free fluoride in F2MBP media incubated with bones showed that the concentration of fluoride was less than 1% of the total amount of fluoride, the fluoride detected by the probe was most likely that of the intact molecule and not free fluoride. The rapid uptake of the F2MBP molecule was supported by assessing the effects of short-term F2MBP treatment on subsequent bone resorption, as determined by the release of 45Ca from prelabeled bones. Bones treated with F2MBP for only 5 min exhibited reductions in the percentage of 45Ca released during the remainder of the 120 h incubation period similar to that when F2MBP was continuously in the medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophoretic separation of tissue-specific serum alkaline phosphatases.

Previous electrophoretic methods for the separation of tissue-specific serum alkaline phosphatases have either been unable to separate the liver and bone enzymes or have been too involved for routine clinical use. A relatively simple electrophoretic method is described which separates placental, liver, bone, and intestinal alkaline phosphatases in serum. The clinical applications of such a method appear to be mainly in the differential diagnosis of liver and bone disease, especially in complicated hypercalcaemic states where tumour metastases can affect both bone and liver, in children, and possibly in cirrhosis of the liver.No differences in electrophoretic mobility could be seen between zymograms of different diseases affecting the same organ. Patients presenting with hepatic cirrhosis all showed a marked serum intestinal alkaline phosphatase zone as well as a liver zone on electrophoresis. An intestinal zone was not present with other types of hepatobiliary disease.The heterogeneity of total serum alkaline phosphatase activity in normal subjects is demonstrated, alkaline phosphatases of liver and bone, and sometimes of intestine being present in normal serum. Results obtained in women in the last trimester of pregnancy and in old people are also discussed.

Diagnostic strategy to monitor diabetic nephropathy.

Although much evidence supports the theory that microalbuminuria is predictive of the development of clinical diabetic nephropathy, other experimental data fail to support this conclusion. It remains unclear whether random urine samples offer as much clinical information as timed overnight or 24 hour samples. Clinical decisions as to treatment based on improved glycemic control or enhanced antihypertensive treatment should be structured to the urinary albumin concentration. Tubular dysfunction is common in diabetes, but is clinical relevance remains unclear.

Production of matrix-degrading enzymes and inhibition of osteoclast-like cell differentiation by fibroblast-like cells from the periodontal ligament of human primary teeth.

Clinically, the most apparent difference between the primary and permanent dentitions is the physiologic loss of the primary tooth by root resorption. Root resorption is associated with loss of integrity of the periodontal ligament (PDL), followed by recruitment of resorptive cells that remove root structure. We therefore cultured primary dentition PDL fibroblasts (PPDL cells) to investigate in vitro their production of matrix metalloproteinases (MMPs) and tissue inhibitors of MMP (TIMPs), and the effects of soluble factors produced by these cells on osteoclast-like cell differentiation. These studies demonstrate that PPDL cells in vitro have a heterogeneous morphology, and they constitutively synthesize 92-kDa gelatinase, 72-kDa gelatinase, and 53/57-kDa procollagenase as well as TIMP-1, -2, and a third inhibitor of matrix metalloproteinase, as determined by substrate gel zymography and immunoblot analysis. Compared with PDL cells from the permanent dentition, PPDL cells generally produced a greater amount of collagenase but similar amounts of the gelatinases and inhibitors. PPDL cells were treated with pro-inflammatory cytokines to determine their effect on the expression of matrix-degrading enzymes and inhibitors. Interleukin-1alpha and tumor necrosis factor-alpha enhanced the constitutive expression of proteinases but not that of inhibitors in PPDL cells. Conditioned media from PPDL cell lines inhibited the differentiation of osteoclast-like cells in mouse bone marrow cultures. These findings indicate that PPDL cells may modulate the cascade of root resorption both by their regulated production of proteinases and inhibitors and by synthesis of unknown soluble factor(s) that may regulate osteoclast development.

Measurement of urinary retinol binding protein by immunonephelometry.

A method is described for the determination of retinol binding protein (RBP) by immunonephelometry. The assay is sensitive to 5 microg/l and has acceptable imprecision. The method correlates with an established ELISA assay. A provisional normal range is proposed for daytime random urine samples. The increased excretion of RBP in adult subject with type 1 diabetes mellitus is demonstrated.

An evaluation of blood creatinine measurement by creatinase on the NOVA M7 blood gas analyzer.

This study compared a creatininase method for the analysis at the bedside of creatinine (CR) in whole blood on a NOVA Biomedical M7 analyser, with rate-Jaffe and creatininase-based laboratory methods. Correlation and precision data were obtained and the effect of increased bilirubin concentration was assessed.

Measurement of urine prostaglandin E2 as a predictor of acute renal transplant rejection: preliminary findings.

A radioimmunoassay for prostaglandin E2 (PGE2) in urine was developed and validated. It was used to provide serial measurements in eight renal transplant patients. Urine PGE2 concentration was increased between 1 and 7 days before any changes in the conventional biochemical indicators of acute rejection, serum creatinine and creatinine clearance. The increases in PGE2 concentration varied from 3 to 50 times that of the previous day. These results suggest that measurement of urinary PGE2 may be useful as an early indicator of acute renal transplant rejection.

The clinical use and measurement of theophylline.

This report reviews the clinical use, metabolism and toxicity of theophylline (Section 1). Current chromatographic and immunoassay methods for theophylline measurement are discussed and practical methods using high-performance liquid chromatography are described (Section 2). Results from the UK National scheme for theophylline quality control and from an experiment to investigate the degree of interference by 1,7-dimethylxanthine in routine assays for theophylline are discussed in Section 3.

Changes in serum ferritin and other 'acute phase' proteins following major surgery.

We have measured ferritin concentrations in healthy women, and ferritin, C-reactive protein, iron and total iron-binding capacity in patients undergoing hysterectomy or major gastrointestinal surgery. Pre-operative serum ferritin concentrations in patients awaiting hysterectomy were significantly lower than those for patients awaiting gastrointestinal surgery and also lower than those for healthy women of similar age. Healthy women aged between 51 and 60 years had significantly higher ferritin levels than women aged 35-50 years. All patients studied showed large increases in serum ferritin and C-reactive protein concentrations after surgery and approximately similar decreases in iron and in total iron-binding capacity.

Comparison of digoxin analysis by EMIT with Immophase and Dac-Cel radioimmunoassay.

The results obtained by an enzyme multiplied immunoassay kit, EMIT, for the measurement of serum digoxin concentration were compared with those from two radioimmunoassay kit methods, Immophase and Dac-Cel. Patients' sera were used to study the correlation between the methods, and three quality control sera with low, intermediate, and high digoxin concentrations were used to study individual method precision. The coefficients of correlation between the three methods varied between 0.915 and 0.951 for serum drug concentrations up to 4.5 nmol/l. There were statistically significant differences between the means of the patients' samples for each method. Precision was acceptable for each method: within-batch percentage coefficient of variation (%CV) less than 8, between-batch %CV less than 10, except for Dac-Cel at low concentration %CV = 18.6. The time taken for the analysis of a batch of 10 samples was between 1.5 and 2 hours, depending on the method.

Faecal elastase 1: a marker of exocrine pancreatic insufficiency in cystic fibrosis.

Pancreatic elastase 1 (E1), a digestive protease, is synthesized by the acinar cells of the pancreas. Using an enzyme-linked immunosorbent assay, we evaluated stool E1 levels in the following groups of patients. (a) Specimens submitted for occult blood examination from 20 adults, over 3 consecutive days, to assess the inter-day variability in E1 excretion. There were no symptoms suggestive of pancreatic insufficiency in this group. The mean E1 concentration over all samples was 457 micrograms E1/g stool (range 124-1683). The intra-assay variation was 6.4% (n = 14) and the inter-assay variation was 8.8% (n = 12). The mean intra-patient variation was 17%. (b) Cystic fibrosis (CF) patients. Eight patients had E1 levels in the reference range (> 200 micrograms E1/g stool). The remaining 25 patients had undetectable E1 levels. (c) A control group of children presenting with unexplained bronchiectasis and/or recurrent respiratory infections and no symptoms of pancreatic dysfunction. The mean E1 concentration in the group was 519 micrograms E1/g stool (range 139-1941). There was no significant difference in E1 concentrations between the two non-CF groups, nor between the pancreatic-sufficient CF patients when compared with both non-CF groups. There was a significant difference between the pancreatic-sufficient and -insufficient CF groups (P < 0.001) using the Mann Whitney U test. All fifteen CF patients who were delta F508 homozygotes had undetectable E1. It may be possible to relate CF genotype to the presence or absence of E1 and to the degree of pancreatic insufficiency. Measurement of faecal E1 in children with CF appears to differentiate them into a group of children with normal pancreatic function and a larger group with severe insufficiency.

Retinol binding protein as a small molecular weight marker of renal tubular function in diabetes mellitus.

A radioimmunoassay has been developed for the measurement in urine of retinol-binding protein (alpha 2-microglobulin) and used as an index of renal tubular function in adult Type 1 (insulin-dependent) diabetics and to define reference ranges in non-diabetic controls. There was a significantly greater excretion (P less than 0.001) of retinol-binding protein in the diabetic group compared to the controls in both overnight and daytime samples. There was a weak positive correlation with albumin excretion (r = 0.33; P less than 0.01) but no correlation with HbA1, duration of diabetes or arterial blood pressure. The results indicate that retinol-binding protein excretion may be increased in diabetic subjects without increased albumin excretion. The possibility therefore exists that renal tubular damage may occur early in diabetic nephropathy without apparent glomerular dysfunction.

A comparison of alveolar bone in young and aged mice.

To study the relationship between aging and alveolar bone loss, the periodontia of young (12-week-old) and aged (94-week-old) C57B1/6 Nia mice were compared, giving special attention to the alveolar bone. The tibiae were also examined to distinguish local from systemic bone changes. The mean area of interproximal bone between the first and second mandibular molars was significantly less in the aged mice than in the young mice. While there was no difference in the distance from the cementoenamel junction (CEJ) to the alveolar crest, the width of the interproximal bone was narrower in the aged animals. The cross-sectional width of the tibia was also reduced in the aged mice, although the total bony area remained constant. In both groups of animals, the distance from the apical extent of the inflammatory infiltrate to the alveolar crest was similar suggesting that alveolar bone loss was not related to inflammation. Other histologic features observed in the teeth of the aged mice, which may have influenced the amount of alveolar bone, were mesial tilting and distal drifting, occlusal wear, and passive eruption. These findings suggest that the greater bone loss in the aged mice may be more related to the aging process and to the functional changes of tooth movement associated with aging than to periodontal disease.

Osteoclast inhibition by factors from cells associated with regenerative tissue.

Guided tissue regeneration (GTR) uses expanded polytetrafluoroethylene (ePTFE) membranes to favor the repopulation of the healing wound with cells with bone regenerative potential. As bone remodeling is a tightly coupled process, inhibition of osteoclast-mediated bone resorption may be critical to regeneration. Thus, this study was undertaken to determine whether cells associated with regenerative tissue can inhibit osteoclast differentiation and activity and to begin characterizing and identifying the factor(s) mediating the observed effects. Conditioned media were harvested from human periodontal cell lines established in culture: cells adherent to ePTFE membranes, recovered from patients after GTR; cells adherent to ePTFE augmentation membranes, recovered from edentulous ridge augmentation procedures; and periodontal ligament cells from periodontally healthy bicuspids. Conditioned medium from each of these regenerative cell lines reduced the number of tartrate-resistant acid phosphatase-positive osteoclast-like cells formed from hemopoietic precursors in mouse bone marrow cultures. Also, both the total resorbed surface area and number of resorption pits formed by these cells on calcium phosphate ceramic films were reduced. The factor in the conditioned medium which inhibited osteoclast differentiation was soluble, heat labile, and resided in the lower molecular weight (< 30 kDa) fraction, the same fraction which would contain cytokines. Western blot analysis of the conditioned medium detected a band at the molecular weight of interferon gamma (IFN-gamma), using a polyclonal rabbit anti-human IFN-gamma. Thus, the factor in the conditioned medium with inhibitory activity may have identity with IFN-gamma or one of the other anti-inflammatory cytokines.

Periodontal ligament cells from insulin-dependent diabetics exhibit altered alkaline phosphatase activity in response to growth factors.

BACKGROUND: Insulin-dependent or Type 1 diabetes mellitus (IDDM) has been associated with an increased severity of periodontal disease. Because periodontal ligament (PDL) cells play a significant role in maintenance and regeneration of mineralized tissue, the success of procedures, such as guided tissue regeneration, is directly related to the ability of these cells to augment mineralized tissue. The objective of this study was to examine the ability of PDL cells from long-standing IDDM patients to form mineralized tissue and to determine whether these cells would exhibit altered responses to exogenously added growth factors. METHODS: PDL cells were isolated from 4 patients with IDDM treated with insulin for at least 5 years and from systemically healthy donors. The cell isolates were tested for their ability to form mineralized nodules in vitro and to express alterations in alkaline phosphatase activity in response to exogenously added growth factors (transforming growth factor-beta (TGF-beta), platelet-derived growth factor-BB (PDGF-BB), and insulin-like growth factor-1 (IGF-1). Alkaline phosphatase activity was determined spectrophotometrically. RESULTS: Although all PDL cell isolates formed mineralized nodules in vitro, PDL cells from diabetics formed mineralized nodules more slowly than did the controls. Alkaline phosphatase activity was not altered by exposure of diabetic PDL cells to TGF-beta for 9 days. In contrast, non-diabetic isolates exhibited increased levels of activity with increasing concentrations, from 0.5 to 1.0 ng/ml. Alkaline phosphatase activity was significantly higher in non-diabetic, but not in diabetic, cell isolates exposed to TGF-beta at 1.0 ng/ml, when compared to non-treated controls. Diabetic cell isolates exhibited significantly lower alkaline phosphatase activity than the non-diabetic isolates when exposed to either TGF-beta, PDGF-BB, IGF-1 or a combination of PDGF-BB and IGF-1. CONCLUSIONS: These results suggest that the populations of PDL cells in insulin-dependent diabetics may be altered in their ability to form mineralized tissue and to respond to growth factors, functions affecting the maintenance and regeneration of the periodontium.

Enhanced production of mineralized nodules and collagenous proteins in vitro by calcium ascorbate supplemented with vitamin C metabolites.

BACKGROUND: Vitamin C or ascorbate is important in wound healing due to its essential role in collagen synthesis. To study wound healing in the periodontium, cells adherent to expanded polytetrafluoroethylene (ePTFE) augmentation membranes, recovered from edentulous ridge augmentation procedures, have been established in culture in our laboratories. The objective of this study was to determine whether treatment of these cells with a calcium ascorbate, which contains vitamin C metabolites (metabolite-supplemented ascorbate), would increase the production of collagenous protein and mineralized tissue in vitro, as compared to unsupplemented calcium ascorbate (ascorbate). METHODS: Cells derived from ePTFE membranes were cultured with beta-glycerophosphate and the test agents for 2 to 5 weeks, and the surface areas of the cell cultures occupied by mineralized nodules were measured using computerized image analysis. One experiment tested the effects of calcium threonate, one of the vitamin C metabolites in metabolite-supplemented ascorbate. Incorporation of radioactive proline and glycine was used as a measure of total protein (radioactivity precipitated by trichloracetic acid) and collagenase-digestible protein (radioactivity released by collagenase digestion.) Co-localization of collagen and fibronectin was examined by immunofluorescence. RESULTS: In vitro treatment of these cells with metabolite-supplemented ascorbate increased the area of the cell cultures occupied by mineralized nodules after 5 weeks. Cell cultures treated with metabolite-supplemented ascorbate also exhibited significant increases in total protein. The increase in collagenous proteins in these cultures accounted for 85% of the increase in total protein. The greatest difference between treatment groups was observed in the cell-associated fraction containing the extracellular matrix. The additional collagen exhibited normal co-distribution with fibronectin. In cultures treated with ascorbate spiked with calcium threonate, the area of mineralized tissue was significantly greater than in ascorbate-treated cultures, but was less than that observed in cultures treated with metabolite-supplemented ascorbate. CONCLUSIONS: In vitro treatment with ascorbate containing vitamin C metabolites enhanced the formation of mineralized nodules and collagenous proteins. Calcium threonate may be one of the metabolites influencing the mineralization process. Identifying factors which facilitate the formation of mineralized tissue has significant clinical ramifications in terms of wound healing and bone regeneration.