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Showing papers by "Boston Children's Hospital published in 1991"


Journal ArticleDOI
TL;DR: The gait analysis laboratory provides quantified assessments of human locomotion which assist in the orthopaedic management of various pediatric gait pathologies by utilizing a video-based data collection strategy similar to commercially available systems for motion data collection.

2,684 citations


Journal ArticleDOI
TL;DR: The aim in developing this micropreparation procedure was to easily and rapidly extract DNA-binding proteins from small numbers of cells, and it gives an excellent yield, comparable to that of the large scale Dignam protocol with minimal proteolysis.
Abstract: We have developed a simple and rapid method for preparing DNA-binding protein extracts from mammalian cells. The protocol is derived from the large scale procedure of Dignam et al. (1) and utilizes hypotonic lysis followed by high salt extraction of nuclei. The technique described by Dignam has several drawbacks, including the need for large numbers of cells and lengthy incubation and dialysis steps. It is labor-intensive and precludes preparation of multiple samples simultaneously. Our aim in developing this micropreparation procedure was to easily and rapidly extract DNA-binding proteins from small numbers of cells. Frequently, the quantity of cells available for extraction of DNA-binding proteins is limiting, as in analysis of clinical samples, of multiple clones of transfected cells, or of COS cell pools transiently transfected with a cDNA expression library. Ideally, such a technique would allow processing of many samples simultaneously and quickly on the benchtop. The method described in this report accomplishes these goals. In addition, it gives an excellent yield of DNA-binding proteins, comparable to that of the large scale Dignam protocol with minimal proteolysis. We typically start with between 5X10 and 10 cells. All centrifugations of less than 30 seconds are carried out in a room temperature microfuge; between steps, the samples are placed on ice. Adherent cells are scraped into 1.5 ml of cold phosphatebuffered saline (PBS); non-adherent cells are pelleted and resuspended in 1.5 ml cold PBS. The cell suspension is then transferred to a microfuge tube. Cells are pelleted for 10 seconds and resuspended in 400 yX cold Buffer A (10 mM HEPES-KOH pH 7.9 at 4°C, 1.5 mm MgCl2, 10 mM KC1, 0.5 mM dithiothreitol, 0.2 mM PMSF) by flicking the tube. The cells are allowed to swell on ice for 10 minutes, and then vortexed for 10 seconds. Samples are centrifuged for 10 seconds, and the supernatant fraction is discarded. The pellet is resuspended in 20—100 y\ (according to starting number of cells) of cold Buffer C (20 mM HEPES-KOH pH 7.9, 25% glycerol, 420 mM NaCl, 1.5 mM MgCl2, 0.2 mM EDTA, 0.5 mM dithiothreitol, 0.2 mM PMSF) and incubated on ice for 20 min for high-salt extraction. Cellular debris is removed by centrifugation for 2 minutes at 4C and the supernatant fraction (containing DNA binding proteins) is stored at -70°C. The yield is 50 to 75 /tg protein per 10 cells.

2,368 citations


Journal ArticleDOI
TL;DR: Doxorubicin therapy in childhood impairs myocardial growth in a dose-related fashion and results in a progressive increase in left ventricular afterload sometimes accompanied by reduced contractility, hypothesized to result in inadequateleft ventricular mass and clinically important heart disease in later years.
Abstract: Background. Cardiotoxicity is a recognized complication of doxorubicin therapy, but the long-term effects of doxorubicin are not well documented. We therefore assessed the cardiac status of 115 children who had been treated for acute lymphoblastic leukemia with doxorubicin 1 to 15 years earlier in whom the disease was in continuous remission. Methods. Eighteen patients received one dose of doxorubicin (45 mg per square meter of body-surface area), and 97 received multiple doses totaling 228 to 550 mg per square meter (median, 360). The median interval between the end of treatment and the cardiac evaluation was 6.4 years. Our evaluation consisted of a history, 24-hour ambulatory electrocardiographic recording, exercise testing, and echocardiography. Results. Fifty-seven percent of the patients had abnormalities of left ventricular afterload (measured as end-systolic wall stress) or contractility (measured as the stress—velocity index). The cumulative dose of doxorubicin was the most significant pr...

1,302 citations


Journal ArticleDOI
22 Feb 1991-Science
TL;DR: This heparin-binding EGF-like growth factor (HB-EGF) binds to EGF receptors on A-431 epidermoid carcinoma cells and smooth muscle cells, but is a far more potent mitogen for smoother muscle cells than is EGF.
Abstract: Macrophage-like U-937 cells secrete a 22-kilodalton heparin-binding growth factor that is mitogenic for BALB-3T3 fibroblasts and smooth muscle cells, but not endothelial cells. The amino acid sequence predicted from complementary DNA clones indicates that the mitogen is a new member of the epidermal growth factor (EGF) family. This heparin-binding EGF-like growth factor (HB-EGF) binds to EGF receptors on A-431 epidermoid carcinoma cells and smooth muscle cells, but is a far more potent mitogen for smooth muscle cells than is EGF. HB-EGF is also expressed in cultured human macrophages and may be involved in macrophage-mediated cellular proliferation.

1,146 citations


Journal ArticleDOI
TL;DR: In children with acute Kawasaki disease, a single large dose of intravenous gamma globulin is more effective than the conventional regimen of four smaller daily doses and is equally safe.
Abstract: Background. Treatment of acute Kawasaki syndrome with a four-day course of intravenous gamma globulin, together with aspirin, has been demonstrated to be safe and effective in preventing coronary-artery lesions and reducing systemic inflammation. We hypothesized that therapy with a single, very high dose of gamma globulin would be at least as effective as the standard regimen. Methods. We conducted a multicenter, randomized, controlled trial involving 549 children with acute Kawasaki syndrome. The children were assigned to receive gamma globulin either as a single infusion of 2 g per kilogram of body weight over 10 hours or as daily infusions of 400 mg per kilogram for four consecutive days. Both treatment groups received aspirin (100 mg per kilogram per day through the 14th day of illness, then 3 to 5 mg per kilogram per day). Results. The relative prevalence of coronary abnormalities, adjusted for age and sex, among patients treated with the four-day regimen, as compared with those treated with...

1,054 citations


Journal ArticleDOI
TL;DR: A good correlation between clinical score and quantitative bacteriology was observed and patients with pulmonary infection could be distinguished by a BI greater than or equal to 5 with a sensitivity of 93% and a specificity of 100% (B-BAL).
Abstract: Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality. A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy. As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is, by a catheter introduced blindly into the bronchial tree. Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia. A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia. For comparison with bacteriologic data we defined a clinical score for pn...

1,007 citations


Journal ArticleDOI
TL;DR: The goal of this review is to describe those stimulators and inhibitors of angiogenesis that have been best-characterized.
Abstract: Proliferation of blood vessels is a process necessary for the nonnal growth and development of tissue (36). In the adult, angiogenesis occurs infrequently. Exceptions are found in the female reproductive system, where angiogenesis occurs in the follicle during its development, in the corpus luteum during ovulation, and in the placenta after pregnancy. These periods of angiogenesis are relatively brief and tightly regulated. Nonnal angiogenesis also occurs as part of the body's repair processes, e.g. in the healing of wounds and fractures. By contrast, uncontrolled angiogenesis can often be pathological. For example, the growth of solid tumors depends on vascularization (37), and in diabetic retinopathy vascularization of the retina often leads to blindness. Given the physiologic and pathological importance of angiogenesis, much effort in the last twenty years has been devoted to the isolation, characteriza­ tion, and purification of factors that can either stimulate or inhibit an­ giogenesis. Several bioassays have been developed to measure angiogenesis. The most common ones are endothelial cell migration (47) and proliferation (38) in vitro, and capillary growth in vivo in the developing chick chorioallantoic membrane (CAM) (4) and the cornea (45). The goal of this review is to describe those stimulators and inhibitors of angiogenesis that have been best-characterized.

990 citations


Journal ArticleDOI
21 Jun 1991-Science
TL;DR: The sequence of a Pst I restriction fragment was determined that demonstrate instability in fragile X syndrome pedigrees and the region of instability was localized to a trinucleotide repeat p(CCG)n as mentioned in this paper.
Abstract: The sequence of a Pst I restriction fragment was determined that demonstrate instability in fragile X syndrome pedigrees. The region of instability was localized to a trinucleotide repeat p(CCG)n. The sequence flanking this repeat were identical in normal and affected individuals. The breakpoints in two somatic cell hybrids constructed to break at the fragile site also mapped to this repeat sequence. The repeat exhibits instability both when cloned in a nonhomologous host and after amplification by the polymerase chain reaction. These results suggest variation in the trinucleotide repeat copy number as the molecular basis for the instability and possibly the fragile site. This would account for the observed properties of this region in vivo and in vitro.

916 citations


Journal ArticleDOI
24 May 1991-Science
TL;DR: This probe provides a means with which to analyze fragile X pedigrees and is a diagnostic reagent for the fragile X genotype.
Abstract: DNA sequences have been located at the fragile X site by in situ hybridization and by the mapping of breakpoints in two somatic cell hybrids that were constructed to break at the fragile site. These hybrids were found to have breakpoints in a common 5-kilobase Eco RI restriction fragment. When this fragment was used as a probe on the chromosomal DNA of normal and fragile X genotype individuals, alterations in the mobility of the sequences detected by the probe were found only in fragile X genotype DNA. These sequences were of an increased size in all fragile X individuals and varied within families, indicating that the region was unstable. This probe provides a means with which to analyze fragile X pedigrees region was unstable. This probe provides a means with which to analyze fragile X pedigrees and is a diagnostic reagent for the fragile X genotype

784 citations


Journal ArticleDOI
TL;DR: A general picture of the disease is presented that includes the clinical, laboratory, and histological findings and reflects the difficulties in making the diagnosis of this frequently misunderstood disorder.

722 citations


Journal ArticleDOI
26 Sep 1991-Nature
TL;DR: X-ray crystallography reveals electron density in the antigen-binding site of HLA-B27 that is an interpretable image of nonameric peptides in a largely extended conformation.
Abstract: X-ray crystallography reveals electron density in the antigen-binding site of HLA-B27 that is an interpretable image of nonameric peptides in a largely extended conformation. Clear density exists for the main chain and several side chains and is consistent with the sequence of 11 nonameric self-peptides eluted from HLA-B27. Pockets in the antigen-binding cleft bind four side chains and the amino and carboxyl termini of the peptide.

Journal ArticleDOI
14 Feb 1991-Nature
TL;DR: The deduced amino-acid sequence of the C5a receptor reveals the expected motifs befitting its interaction with cellular GTP-binding proteins.
Abstract: HOST defence and inflammatory responses are controlled and amplified by receptor-mediated events often initiated by a chemotactic factor that directs the approach of phagocytic cells1. Complement receptors CR1 and CR3 are responsible for the phagocytic and adhesive properties of neutrophils 2,3, whereas the C5a receptor mediates the pro-inflammatory and chemotactic actions of the complement anaphylatoxin CSa4–6. In addition to stimulating chemotaxis, granule enzyme release and superoxide anion production, this receptor stimulates upregulation of expression and activity of the adhesion molecule MAC-1, and of CR1, and a decrease in cell-surface glycoprotein 1 GOMEL-14 on neutrophils7–9. In vivo, the C5a receptor may participate in anaphylactoid and septic shock 10–12. The human C5a receptor was cloned from U937 and HL-60 cells and identified by high affinity binding when expressed in COS-7 cells. The deduced amino-acid sequence of the receptor reveals the expected motifs befitting its interaction with cellular GTP-binding proteins.

Journal ArticleDOI
01 Jan 1991-Toxicon
TL;DR: It is concluded that venom researchers must be aware of venom variability both in selecting their sources of venom and in interpretation of results, and producers of antivenom must utilize an understanding of such variability in selecting Sources of venom for antivenOM production to ensure representation of all venom types required within each antivenoms.

Journal ArticleDOI
Earl A. Palmer1, John T. Flynn2, Robert J. Hardy3, Dale L. Phelps4  +181 moreInstitutions (24)
TL;DR: The timing of retinal vascular events correlated more closely with postconceptional age than with postnatal age, implicating the level of maturity more than postnatal environmental influences in governing the timing of these vascular events.

Journal ArticleDOI
18 Oct 1991-Cell
TL;DR: The existence of at least seven genes encoding FGF family members, at least four genes encoding high affinity recep- tors, and heterogeneous populations of HSPG low affinity receptors on cell surfaces and in the extracellular matrix suggests novel mechanisms for regulating FGF activity and determining responsiveness of target cells to FGF.

Journal ArticleDOI
20 Sep 1991-Cell
TL;DR: In this multistep tumorigenesis pathway of dermal fibrosarcomas, there appears to be a discrete switch to the angiogenic phenotype that correlates with the export of bFGF, a knownAngiogenic factor.

Journal ArticleDOI
TL;DR: The results of this study, in which dexamethasone administration began before the initiation of cefotaxime therapy, provide additional evidence of a beneficial effect of dexamETHasone therapy in infants and children with bacterial meningitis.
Abstract: Background. In experimental models of meningitis and in children with meningitis, dexamethasone has been shown to reduce meningeal inflammation and to Improve the outcome of disease. Methods. We conducted a placebo-controlled, double-blind trial of dexamethasone therapy in 101 infants and children admitted to the National Children's Hospital, San Jose, Costa Rica, who had culture-proved bacterial meningitis or clinical signs of meningitis and findings characteristic of bacterial infection on examination of the cerebrospinal fluid. The patients were randomly assigned to receive either dexamethasone and cefotaxime (n = 52) or cefotaxime plus placebo (n = 49). Dexamethasone (0.15 mg per kilogram of body weight) was given 15 to 20 minutes before the first dose of cefotaxime and was continued every 6 hours thereafter for four days. Results. The demographic, clinical, and laboratory profiles were similar for the patients in the two treatment groups. By 12 hours after the beginning of therapy, the mean ...

Journal ArticleDOI
TL;DR: It is suggested that the FPR in normal subjects may be lower than previously believed and patients with Cushing's syndrome demonstrated unequivocal elevation of FPR and cortisol concentration correlated during each sample period in normal volunteers, indicating that cortisol secretion, rather than metabolism, is mainly responsible for changes in plasma cortisol.
Abstract: Growth retardation as well as the development of Cushingoid features in adrenally insufficient patients treated with the currently accepted replacement dose of cortisol (33-41 mumol/day.m2; 12-15 mg/m2.day) prompted us to reevaluate the cortisol production rate (FPR) in normal subjects and patients with Cushing's syndrome, using a recently developed thermospray liquid chromatography-mass spectrometry method. The stable isotope [9,12,12-2H3]cortisol was infused continuously for 31 h at about 5% of the anticipated FPR. Blood samples were obtained at 20-min intervals for 24 h, spun, and pooled in 4-h groups. Tracer dilution in plasma was determined by liquid chromatography/mass spectrometry. The method was validated with controlled infusions in 6 patients with adrenal insufficiency. Results from 12 normal volunteers revealed a FPR of 27.3 +/- 7.5 mumol/day (9.9 +/- 2.7 mg/day) or 15.7 mumol/day.m2; 5.7 mg/m2. day). A previously unreported circadian variation in FPR was observed. Patients with Cushing's syndrome demonstrated unequivocal elevation of FPR and cortisol concentration correlated during each sample period in normal volunteers, indicating that cortisol secretion, rather than metabolism, is mainly responsible for changes in plasma cortisol. Our data suggest that the FPR in normal subjects may be lower than previously believed.

Journal ArticleDOI
01 Dec 1991-Blood
TL;DR: Clinical and laboratory findings are compatible with reported in vitro and in vivo effects of several inflammatory cytokines and indicate that studies of FHL may contribute to the understanding of cytokine effects in vivo.

Journal ArticleDOI
TL;DR: Although approximately two thirds of the ELBW group were performing in the normal range on intellectual measures, comparison with the control group suggests that, as a group, ELBW children were significantly disadvantaged on every measure tested.

Journal ArticleDOI
09 May 1991-Nature
TL;DR: It is reported here that binding and uptake of cultured rat P. carinii by human and rat alveolar macrophages is reduced by 90% in the presence of competitive inhibitors of mannose receptor activity and by adherence of alveolars macrophage to mannan-coated surfaces.
Abstract: Human exposure to Pneumocystis carinii is common but, in the absence of acquired or genetic dysfunction of either cellular or humoral immunity, exposure rarely leads to illness. Although alveolar macrophages can degrade P. carinii, macrophage receptors involved in P. carinii recognition have not been clearly defined. Characterization of a predominant surface glycoprotein of the high mannose type led us to investigate the role of the macrophage mannose receptor in this process. We report here that binding and uptake of cultured rat P. carinii by human and rat alveolar macrophages is reduced by 90% in the presence of competitive inhibitors of mannose receptor activity and by adherence of alveolar macrophages to mannan-coated surfaces. Further, only those COS cells transfected with the human macrophage mannose receptor complementary DNA that express surface mannose receptors bind and ingest P. carinii. These studies establish that the macrophage mannose receptor is sufficient for uptake of P. carinii and emphasize the role of the alveolar macrophage in first-line host defence against P. carinii.

Journal ArticleDOI
TL;DR: In a cohort of 170 middle and upper-middle class children participating in a prospective study of child development and low-level lead exposure, higher blood lead levels at age 24 months were associated with lower scores at age 57 months on the McCarthy Scales of Children's Abilities.
Abstract: In a cohort of 170 middle and upper-middle class children participating in a prospective study of child development and low-level lead exposure, higher blood lead levels at age 24 months were associated with lower scores at age 57 months on the McCarthy Scales of Children's Abilities. The mean blood lead level at age 24 months was 6.8 micrograms/dL (SD = 6.3; 75th, 90th, and 99th percentiles: 8.8, 13.7, 23.6, respectively) and for all but 1 child was less than 25 micrograms/dL, the current definition of an "elevated" level. After adjustment for confounding, scores on the General Cognitive Index decreased approximately 3 points (SE = 1.4) for each natural log unit increase in 24-month blood lead level. The inverse association between lead level and performance was especially prominent for visual-spatial and visual-motor integration skills. Higher prenatal exposures were not associated with lower scores at 57 months except in the subgroup of children with "high" concurrent blood lead levels (ie, greater than or equal to 10 micrograms/dL). The concentration of lead in the dentine of shed deciduous teeth was not significantly associated with children's performance after adjustment for confounding.

Journal ArticleDOI
TL;DR: Bone as a source of lead to the rest of the body and as a record of past lead exposure is discussed and proposed numerical values for the changes in blood lead levels that occur with changes in turnover rates are presented.
Abstract: This article discusses bone as a source of lead to the rest of the body and as a record of past lead exposure. Bone lead levels generally increase with age at rates dependent on the skeletal site and lead exposure. After occupational exposure, the slow decline in blood lead, a 5- to 19-year half-life, reflects the long skeletal half-life. Repeated measurements of bone lead demonstrate the slow elimination of lead from bone. Stable isotope ratios have revealed many details of skeletal uptake and subsequent release. The bulk turnover rates for compact bone are about 2% per year and 8% for spine. Turnover activity varies with age and health. Even though lead approximates calcium, radium, strontium, barium, fluorine, and other bone seekers, the rates for each are different. A simple, two-pool (bone and blood) kinetic model is presented with proposed numerical values for the changes in blood lead levels that occur with changes in turnover rates. Two approaches are offered to further quantify lead turnover. One involves a study of subjects with known past exposure. Changes in the ratio of blood lead to bone lead with time would reflect the course of bone lead availability. Also, stable isotopes and subjects who move from one geographical area to another offer opportunities. Sequential isotope measurements would indicate how much of the lead in blood is from current exposure or bone stores, distinct from changes in absorption or excretion.

Journal ArticleDOI
TL;DR: FHL is an underdiagnosed disease and in only 11/32 children was diagnosis made during their lifetime, so it is important to be aware of the disorder as potential therapy now exists.
Abstract: We retrospectively studied the incidence of familial hemophagocytic lymphohistiocytosis (FHL) in children during the 16-year period 1971-86. First, all departments of pediatrics, pathology, and infectious diseases were enquired for children with FHL or disorders resembling FHL. Secondly, the causes of death of all children who died during the study period in Sweden (n = 19,542) were also investigated. Files and histological specimens were further studied in selected children. By using a set of inclusion/exclusion criteria, we found 32 children with FHL. The incidence was 1.2/1,000,000 children per year. One child per 50,000 live borns developed FHL during this period. The sex ratio was close to 1:1. Prominent early clinical signs were fever (91%), splenomegaly (84%), hepatomegaly (90%), rash (43%), and lymph node enlargement (42%). Neurological symptoms, which developed in 47%, could totally dominate the clinical picture and develop prior to other symptoms and signs. Common laboratory findings were pancytopenia, hypertriglyceridemia, hypofibrinogenemia, elevated serum transaminases, hyperbilirubinemia, hyponatremia, hypoalbuminemia, and a moderate spinal fluid pleocytosis. Chest X-ray often revealed mostly discrete pulmonary infiltrates. FHL is an underdiagnosed disease and in only 11/32 children was diagnosis made during their lifetime. It is important to be aware of the disorder as potential therapy now exists.

Journal ArticleDOI
TL;DR: Comparisons between different beta/A4 sequences demonstrated that the fibrillar structure representative of AD amyloid was dependent upon electrostatic interactions, likely involving His-13 and Asp-23, and hydrophobic interactions between uncharged sidechains contained within residues 17-21.

Journal ArticleDOI
01 Feb 1991-Science
TL;DR: The involvement of ARP-1 in the regulation of apoAI gene expression suggests that it may participate in lipid metabolism and cholesterol homeostasis.
Abstract: Apolipoprotein AI (apoAI) is a lipid-binding protein that participates in the transport of cholesterol and other lipids in the plasma. A complementary DNA clone for a protein that bound to regulatory elements of the apoAI gene was isolated. This protein, designated apoAI regulatory protein-1 (ARP-1), is a novel member of the steroid hormone receptor superfamily. ARP-1 bound to DNA as a dimer, and its dimerization domain was localized to the COOH-terminal region. ARP-1 also bound to a thyroid hormone-responsive element and to regulatory regions of the apoB, apoCIII, insulin, and ovalbumin genes. In cotransfection experiments, ARP-1 downregulated the apoAI gene. The involvement of ARP-1 in the regulation of apoAI gene expression suggests that it may participate in lipid metabolism and cholesterol homeostasis.


Journal ArticleDOI
TL;DR: A retrospective, multivariate statistical analysis of 129 consecutive nonsyndromic patients undergoing cleft palate repair was performed to document the incidence of postoperative fistulas, to determine their cause, and to review methods of surgical management.
Abstract: A retrospective, multivariate statistical analysis of 129 consecutive nonsyndromic patients undergoing cleft palate repair was performed to document the incidence of postoperative fistulas, to determine their cause, and to review methods of surgical management. Nasal-alveolar fistulas and/or anterior palatal fistulas that were intentionally not repaired were excluded from study. Cleft palate fistulas (CPFs) occurred in 30 of 129 patients (23 percent), although nearly a half were 1 to 2 mm in size. Extent of clefting, as estimated by the Veau classification, was significantly more severe in those patients who developed cleft palate fistula. Type of palate closure also influenced the frequency of cleft palate fistula. Forty-three percent of patients undergoing Wardill-type closures developed cleft palate fistula versus 10, 22, and 0 percent for Furlow, von Langenbeck, and Dorrance style closures, respectively. The fistula rate was similar in patients with (30 percent) and without (25 percent) intravelar veloplasty. Age at palate closure did not significantly affect the rate of fistulization; however, the surgeon performing the initial closure did not have an effect. Thirty-seven percent of patients developed recurrent cleft palate fistulas following initial fistula repair. Recurrence of cleft palate fistulas was not influenced by severity of cleft or type of original palate repair. Following end-stage management, a second cleft palate fistula recurrence occurred in 25 percent of patients. Continued open discussion of results of cleft palate repair is recommended.

Journal ArticleDOI
TL;DR: A comparison of the maturation characteristics of synthetic carbonated apatites with bone mineral indicates that a simple, passive, physicochemical maturation process cannot explain the changes observed in the mineral phase of whole bone tissue or in the density centrifugation fractions of bone during aging and maturation.
Abstract: The environment of CO32− ions in the bone mineral of chickens of different ages and in bone fractions of different density have been investigated by resolution-enhanced Fourier Transform Infrared (FTIR) Spectroscopy Three carbonate bands appear in thev2 CO3 domain at 878, 871, and 866 cm−1, which may be assigned to three different locations of the ion in the mineral: in monovalent anionic sites of the apatitic structure (878 cm−1), in trivalent anionic sites (871 cm−1), and in unstable location (866 cm−1) probably in perturbed regions of the crystals The distribution of the carbonate ions among these locations was estimated by comparing the intensities of the corresponding FTIR spectral bands The intensity ratio of the 878 and 871 cm−1 bands remains remarkably constant in whole bone as well as in the fractions obtained by density centrifugation On the contrary, the intensity ratio of the 866 cm−1 to the 871 cm−1 band was found to vary directly and decreased with the age of the animal In bone of the same age, the relative content of the unstable carbonate ion was found to be highest in the most abundant density centrifugation fraction A resolution factor of the CO32− band (CO3 RF) was calculated from the FTIR spectra which was shown to be very sensitive to the degree of crystallinity of the mineral The crystallinity was found to improve rapidly with the age of the animal The CO3 RF in the bone samples obtained by density centrifugation from bone of the same animal was found to be essentially constant This indicates a fairly homogeneous, crystalline state of the mineral phase A comparison of the maturation characteristics of synthetic carbonated apatites with bone mineral indicates that a simple, passive, physicochemical maturation process cannot explain the changes observed in the mineral phase of whole bone tissue or in the density centrifugation fractions of bone during aging and maturation

Journal ArticleDOI
22 Feb 1991-Cell
TL;DR: There is no simple relationship between the degree of methylation and either the level of expression of the fragile site or the severity of the clinical phenotype in the fragile X syndrome.