Osseointegration of titanium implants in the tibia. Electron microscopy of biopsies from 4 patients

We studied the ultrastructure of bone tissue around implants of pure titanium inserted into the tibia in 4 patients with arthrosis or rheumatoid arthritis. Three main appearances of the interface were noted. First, a close contact between titanium and calcified bone with living osteocytes inside the newly-formed bone was observed in all samples. Secondly, a close contact was also seen between the implant and osteoid, the newly formed collagenous matrix being either uncalcified or calcifying. Thirdly, a loose extracellular matrix with fibrillar and nonfibrillar materials was sometimes observed between bone mineral and implant. There was no inflammatory reaction at the interface. We concluded that the titanium implants were osseointegrated, but the calcification of the bone tissue was not complete even after 20 months. However, mineralization of osteoid and living bone cells revealed the presence of an active tissue.

Ultrastructural localization of endogenous hormones and receptors in bone tissue: an immunocytological approach in frozen samples

In addition to their well-known mechanical role, bones are essential for the regulation of calcium phosphate metabolism. Most of the peptide and steroid hormones acting on bone tissue exert their cellular effects directly on bone cells after binding to cell receptors. A combined method using immunocytology on ultrathin frozen sections has been applied to bone tissue and made possible the ultrastructural localization of endogenous hormones and hormone receptors. There is immunocytological evidence, at the osteoblast level, for: (1) the presence of calcitonin, parathyroid hormone, growth hormone, 1,25 dihydroxyvitamin D3, aldosterone, corticosterone and progesterone; (2) the existence of 1,25 dihydroxyvitamin D3 and progesterone receptors; (3) the absence of estradiol and receptors, testosterone and gonadoliberin. Ultimate goals of future studies are to extend the ultrastructural localization of hormones at the osteoclast level, to assess the distribution of adhesive proteins and of their receptors in bone cells and matrix, and to use well-calcified human bone samples in order to evaluate better the role of therapeutic agents.

An analysis of the communication of adult residents of a long-term care hospital as perceived by their caregivers

Different groups of caregivers (nurses, orderlies, professionals, student orderlies and volunteers) who were in frequent interaction with residents from a long-term care hospital were interviewed with a nominal group process. They were asked to identify concrete situations of communication in which residents with no trouble communicating, residents with aphasia and residents with dementia need to express and/or comprehend a message. A total of 196 statements were recorded and coded using a qualitative approach into different categories of communication acts specific to daily life situations and several categories of generic communication acts, which are unrelated to the daily routine of care and treatment. The results show that communication in daily life situations varies little in relation to the different residents. However, residents with language disorders are perceived to be less involved in generic communication acts than residents with no communication disorder. They also demonstrate that the perceptions of communication of the different caregivers vary. The results are discussed in relationship to the conception of an evaluation instrument for language-impaired long-term care residents, which will help in determining intervention as well as the objective evaluation of its effects.

Intravenous ciprofloxacin disposition in obesity

The pharmacokinetics of ciprofloxacin and its metabolite 1 (desethyleneciprofloxacin) were studied in 17 obese men (mean age, 29.2 +/- 7.5 years; mean weight, 110.7 +/- 20.2 kg; mean body mass index, 36.4 +/- 3.9 kg/m2) and 11 control subjects (men of normal weight; mean age, 25.0 +/- 5.1 years; mean weight, 71.8 +/- 9.9 kg; mean body mass index, 23.3 +/- 2.4 kg/m2). Each subject received a single 400 mg intravenous dose of ciprofloxacin infused over 1 hour. Ciprofloxacin total clearance was significantly increased in obese subjects compared with control subjects (897.44 +/- 159.57 versus 744.44 +/- 120.51 ml/min, respectively; p < 0.05). Ciprofloxacin renal clearance in obese subjects (637.58 +/- 128.89 ml/min) was 29% higher than in control subjects (495.47 +/- 137.85 ml/min; p < 0.05). The elimination half-life values of ciprofloxacin and desethyleneciprofloxacin were not statistically different between groups. Ciprofloxacin steady-state volume of distribution (Vss) was significantly larger in obese group (269.17 +/- 51.64 versus 219.03 +/- 35.80 L; p < 0.01) compared with the control group, and when it was normalized by total body weight, obese subjects exhibited lower Vss/kg than control subjects (2.46 +/- 0.42 versus 3.06 +/- 0.31 L/kg; p < 0.001). These findings indicate that ciprofloxacin is distributed less to adipose tissue than to other tissues, but partial distribution to adipose tissue does occur. To normalize the volume of distribution of obese subjects to that of normal weight subjects, 45% of excess weight (total body weight minus ideal body weight) must be added to the ideal body weights of obese subjects.

Fluoride increases rat osteoblast function and population after in vivo administration but not after in vitro exposure

The effects of fluoride on bone tissue are now well documented by in vivo histological studies performed on both human and animal bone biopsies and demonstrating an increase in osteoblast (OB) population. In order to elucidate whether the mechanism of action of fluoride on osteoblasts was direct or indirect, 14 three-week-old Sprague-Dawley rats were selected. Seven animals received 100 ppm fluoride as sodium fluoride (NaF) in drinking water for one month. The other animals, which did not receive fluoride, were considered as controls. At the end of the experiment, femurs and vertebrae were excised and osteoblastic cells were obtained after collagenase digestion separately from each animal. The osteoblastic cells derived from control and NaF-treated rats were exposed in vitro to 10(-5) M NaF. Alkaline phosphatase (AP) activity was measured, and the cellular proliferation was assessed by 3H-thymidine incorporation. Thymidine incorporation and AP activity were significantly higher in osteoblastic cells derived from NaF-treated rats than in cells obtained from control rats (p = 0.05 and p < 0.01, respectively). In contrast, the osteoblast proliferation and activity were not modified after in vitro exposure to NaF in cells derived from control and NaF-treated rats. In conclusion, the function of osteoblasts was not modified after in vitro exposure to fluoride. In contrast, given in vivo to rats for one month, fluoride has a mitogenic effect on osteoblasts and stimulates their activity. These data emphasize the hypothesis that fluoride may act either on osteoprogenitor cells or through an indirect mechanism mediated by a cofactor.

Evidence for a direct effect of growth hormone on osteoblasts

In order to determine whether growth hormone (GH) exerts a direct effect on osteoblasts, in vitro and in vivo immunocytological studies were carried out on newborn rat calvaria and a clonal osteoblast-like cell line (MC3T3-E1) isolated from newborn mouse calvaria. After exposure to human growth hormone (hGH) or 1,25 dihydroxyvitamin D3 (1,25(OH)2D3), a significant increase in alkaline phosphatase activity was observed in MC3T3-E1 cells. Simultaneous exposure of MC3T3-E1 cells to hGH and 10 nM 1,25(OH)2D3 showed a synergistic effect of the two hormones on this activity. The optimal dose of hGH was 0.1 nM. An immunocytological procedure was performed on ultrathin frozen sections from 7-day-old rat calvaria and MC3T3-E1 cells cultured with hGH. GH-like immunoreactivity was observed in both cases. In calvaria, endogenous GH-like immunoreactivity was localized at the same ultrastructural level (plasma membrane, cytoplasmic and nuclear matrices) as exogenous GH-like immunoreactivity in MC3T3-E1 cells. Following the initial step of binding to the plasma membrane, GH may be internalized in the cytoplasmic matrix and nucleus. In situ hybridization revealed the presence of mRNA coding for GH receptor in calvaria cells. The density of these receptors seemed to be lower in osteoblasts than in hepatocytes. In MC3T3-E1 cells, hGH induced a dose-dependent secretion of insulin-like growth factor 1. In conclusion, these results indicate that GH may act directly on osteoblasts.

Ganciclovir susceptibilities of cytomegalovirus (CMV) isolates from solid organ transplant recipients with CMV viremia after antiviral prophylaxis

Ganciclovir susceptibility studies were done on the last cytomegalovirus (CMV) isolate available from 42 solid organ transplant recipients with CMV viremia who were enrolled in a prospective CMV prophylactic trial. Viruses were categorized as follows: 13 isolates (group 1) from patients who received ganciclovir prophylaxis; 9 isolates (group 2) from patients who received acyclovir prophylaxis; 8 isolates (group 3) from patients who received acyclovir prophylaxis and ganciclovir treatment; and 12 isolates (group 4) from patients who received prophylaxis and treatment with ganciclovir. All CMV isolates were sensitive to ganciclovir (mean 50% inhibitory concentration [IC50] 1.7 microM; range, 0.2-5.3 microM). Mean IC50 values (in microM) were 1.7 for group 1 isolates, 1.2 for group 2 isolates, 2.2 for group 3 isolates, and 1.7 for group 4 isolates (P > .05). Thus, acyclovir or ganciclovir prophylaxis in solid organ transplant patients did not select ganciclovir-resistant isolates of CMV.

Relationship between bone fluoride content and histological evidence of calcification defects in osteoporotic women treated long term with sodium fluoride

Fluoride treatment is used to increase bone formation and cancellous bone mass in patients suffering from postmenopausal osteoporosis with vertebral fractures. Patients submitted to similar therapeutic protocols have shown various histological responses to the treatment, some developing calcification defects and others not. In fact, the bone histological response to fluoride salts depends on the cumulative uptake of fluoride by bone. To clarify the relationship between the presence of calcification defects (identified by the presence of mottled bone and linear formation defects) and the bone fluoride content, a retrospective study was performed on 29 women with type 1 osteoporosis and treated for several months (11-24) with sodium fluoride (50 mg/day), calcium and vitamin D. Bone fluoride content always significantly increased after treatment, but it was significantly higher in patients showing calcification defects than in those having no defects. These differences between the two groups of patients were not due to differences in clinical details (no significant differences concerning age, duration of treatment, total amount of fluoride ingested, renal function) or in their bone remodelling activity. Thus, it may be hypothesized that the high bone fluoride uptake is due to different individual responses from one patient to another concerning the bioavailability of the same dose of fluoride. This is difficult to predict, except by testing the individual bioavailability of the compound to be used in each patient before starting long-term treatment.

Random amplified polymorphic DNA markers for DNA fingerprinting and genetic variability assessment of minute parasitic wasp species (Hymenoptera: Mymaridae and Trichogrammatidae) used in biological control programs of phytophagous insects

Biological control of insects that feed on our crops has become more practical in recent years by mass release of egg parasitoid microhymenoptera. Trichogramma species are now commercially reared and spread in commercial fields to control specific insect pests. Microhymenoptera species are, however, very small and morphologically indistinguishable within species, although strains of a given species differ in their efficiency to control specific insect pests. Traditional taxonomy is unable to differentiate microhymenoptera species at the strain level. It is becoming increasingly important to develop a reliable system to monitor genetic variations both within and between strains of commercially important microhymenoptera, to detect genetic drift occurring during several generations of multiplication, to protect patents, and to certify the lots of commercially released microhymenoptera. We have developed a system based on DNA markers to rapidly characterize individuals of five species of microhymenoptera from the genus Anaphes and Trichogramma including a new species of Anaphes not previously described. The main components of our system are a rapid and simple DNA micro-extraction method and fast DNA polymorphism analyses based on random amplified polymorphic DNA markers.

A mathematical model for fluoride uptake by the skeleton

A mathematical model was developed that predicts fluoride accumulation and clearance from the skeleton based upon fluoride bioavailability, bone remodeling rate, and the fluoride binding characteristics of bone. It was assumed that fluoride binds to bone in a nonlinear fashion such that a smaller percentage of fluoride is bound to bone if fluoride intake is increased to high levels. Bone resorption rate was assumed to be proportional to the solubility of hydroxyfluoroapatite which is inversely related to bone fluoride content. The predictions made by the model compared favorably with experimental results from fluoride uptake and clearance studies. Parametric studies done using the model showed the following: (1) fluoride can be cleared from the skeleton by bone remodeling, but fluoride clearance takes over four times longer than does fluoride uptake; and (2) fluoride uptake by the skeleton was positively associated with bone remodeling rate. However, the concentration of fluoride in newly formed bone does not decrease with reduced remodeling rates and surpasses 10,000 ppm for intakes of fluoride greater than 9 mg/day. For osteoporosis, daily dose and duration of fluoride treatment should be selected to avoid reaching a toxic cumulative bone fluoride content.

Acyclovir susceptibilities of herpes simplex virus strains isolated from solid organ transplant recipients after acyclovir or ganciclovir prophylaxis

We determined the acyclovir (ACV) susceptibilities of herpes simplex virus (HSV) isolates (n = 18) recovered from solid organ transplant patients after antiviral prophylaxis with ACV or ganciclovir. All isolates tested were susceptible to ACV (50% inhibitory concentration, < 1 microM). A clinical review of patients with HSV disease showed that all improved with specific anti-HSV therapy, and no recurrences were reported.

[The emergence of viruses resistant to antiviral agents: a new challenge]

Recent use of antiviral drugs and the increase in the number of viral infections in immunocompromised hosts have led to the development of viral resistance. In this paper, the author reviews the antiviral drugs on the market, the antiviral susceptibility tests and presents a review of the literature concerning infections with resistant viruses. Acyclovir-resistant herpes simplex and varicella-zoster virus, ganciclovir-resistant cytomegalovirus and zidovudine-resistant human immunodeficiency virus will be discussed.

In vitro induction of a calcifying matrix by biomaterials constituted of collagen and/or hydroxyapatite: an ultrastructural comparison of three types of biomaterials

The induction of a calcifying matrix was studied in vitro and compared for three biomaterials (collagen sponge, hydroxyapatite material and a mixture of both (Biostite)) cultured with human osteoblast-like cells. The influence of biomaterials on organic matrix synthesis and the calcification process was analysed at the ultrastructural level (transmission electron microscopy and X-ray microanalysis). Biomaterials were well tolerated by bone cells. Whichever biomaterial was used, osteoblasts proliferated and synthesized a new matrix constituted of fibrillar and non-fibrillar elements. This activity appeared earlier and was more intense with Biostite than with collagen sponge alone. A deposition of a mineral substance in this newly formed matrix was observed with the collagen sponge and Biostite, but never with hydroxyapatite alone. The mineral deposits were identified as hydroxyapatite crystals, similar to those observed and analysed in bone tissue. These in vitro observations clearly demonstrated the property of Biostite to produce a calcified collagenous matrix similar to bone tissue. However, in vivo confirmation is required before extending the use of this biomaterial to periodontology.

In vitro exposure to sodium fluoride does not modify activity or proliferation of human osteoblastic cells in primary cultures

The anabolic effects of sodium fluoride (NaF) on trabecular bone mass in osteoporosis is now well established. In vivo histologic studies performed in humans and other animals have shown that fluoride induces an increase in osteoblast number at the tissue level. To determine the mechanisms of action of fluoride on osteoblasts, we studied the effects of NaF on short- and long-term cultures of human osteoblastic cells derived from bone explants obtained from 21 donors. In short-term experiments, bone-derived cells were exposed to NaF for 4 days. At doses ranging from 10(-11) to 10(-5) M, NaF did not modify the alkaline phosphatase (AP) activity or osteocalcin secretion. In long-term experiments, half the bone samples from 15 donors were cultured for 4 months in the presence of 10(-5) M NaF and the other half were maintained in NaF-free medium. Observations by light and electron microscopy disclosed no morphologic modification in bone explants after 4 months of exposure to NaF, despite an increase in the bone fluoride content. After the first month of culture, slight but not significant increases were noted in 6 of 10 cases for AP activity, 4 of 10 for osteocalcin secretion, and 5 of 7 for [3H]thymidine incorporation. After 4 months of culture in the presence of NaF, no change in AP activity or cell proliferation was noted. In contrast, the osteocalcin secretion significantly decreased (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

X-ray microanalysis of fluoride distribution in microfracture calluses in cancellous iliac bone from osteoporotic patients treated with fluoride and untreated

Fluoride is able to augment cancellous bone mass in vertebral osteoporosis but is responsible for osteoarticular side effects in which microfractures are thought to be involved. During healing of these microfractures, a callus is formed all around the cancellous fracture line. Our hypothesis is that in fluoride-treated osteoporotic patients, calluses are bone sites where fluoride is focally deposited at a high concentration, and this could induce a local defect of calcification with a poor healing of microfractures. Our aim was to validate this hypothesis on several calluses following microfractures in undecalcified iliac cancellous bone from six women with osteoporosis (four fluoride treated and two untreated). Histologically normal iliac cancellous bone tissue, taken from a subject having neither fluoride treatment nor microfracture, was also examined. Selected areas, including new woven bone (calluses) and old lamellar bone, were carbon-coated and analyzed using an electron microprobe. Fluoride K alpha and calcium K alpha radiations were detected with wavelength and energy-dispersive spectrometers, respectively. In old lamellar bone at a distance from microfractures, the fluoride level was similar in normal and untreated osteoporotic patients but was slightly increased in treated osteoporotic patients. In untreated osteoporotic patients, the fluoride level was slightly higher (about 1.2 times) at the site of microfractures (lamellar and woven bone) than in lamellar bone far from such fractures, but fluoride was homogeneously distributed in lamellar and woven bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluoride-induced bone changes in lambs during and after exposure to sodium fluoride

The evolution of bone changes induced by fluoride after the end of exposure was investigated in lambs. Sodium fluoride (NaF) was given orally at a dose of 3.5 mg/kg per day to 14 animals for 120 days. A group of 7 control and 7 treated lambs was slaughtered at the end of NaF administration (T120) and another group 120 days after the end of NaF exposure (T240). At T120, the bone fluoride content (BFC) was very significantly increased in treated animals. The histomorphometric analysis confirmed that fluoride induces an increase in bone formation (the osteoid perimeter and area were 3-fold and 4.5-fold higher respectively in treated than in control animals). The number of osteoblasts was significantly augmented. Serum osteocalcin level was twice as high in treated animals compared with controls. The bone formation rate at the tissue level (BFR) doubled after treatment, but the apposition rate (Aj.AR) was half that in the control group. The mineralization lag time (Mlt) was 120 days in treated animals compared with 42 days in controls. At T240, BFC had decreased by 50% compared with the level at T120, but it was still significantly higher than in controls. The osteoid and osteoblastic parameters were 2 and 1.3 times higher than in control animals. BFR remained significantly increased in treated animals, but Aj.AR and Mlt were similar in control and treated animals. In conclusion, after 4 months of NaF exposure fluoride induced an increase in osteoblast natality and bone formation at the tissue level, associated with a toxic effect at the individual cell level.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ossein-hydroxyapatite compound on ewe bone remodeling: biochemical and histomorphometric study

Ossein-hydroxyapatite compound (OHC) is a protein-mineral complex derived from bovine bone. Its effects on bone remodeling were studied in old ewes which have seasonal variations in bone remodeling. Seven animals received 200 mg OHC/kg b.w./day for 90 days from July to September. The control group consisted of 7 untreated animals followed for the same period of time. OHC was administered through a fistula into the fourth stomach. A significant decrease of bone histomorphometric parameter values was noted in controls at the end of the experiment, due to seasonal variations: the cancellous eroded perimeter decreased by 45%, the osteoblastic perimeter by 60% and the bone formation rate at the cell level by 20%. In contrast, in the treated-group, these parameters tended to increase or did not change. In conclusion, counteracting the significant seasonal reduction of bone remodeling in ewes, OHC seems able to stimulate directly or indirectly bone metabolism, especially when osteoblast activity is reduced and may partly prevent the seasonal reduction of bone turnover.

Dose effects on ewe bone remodeling of short-term sodium fluoride administration--a histomorphometric and biochemical study

The early effects of two doses of sodium fluoride (NaF) on bone remodeling was studied in 14 ewes divided into two groups. Group I received orally 1 mg NaF/kg/day and group II received a five-fold greater dose. No calcium supplement was given. Transiliac bone biopsies and blood samples were taken before treatment (T0) and after 45 (T45) days of treatment. Bone fluoride content significantly increased in group II. In both groups, a significant decrease of serum calcium and phosphorus, and a slight but nonsignificant augmentation in serum parathyroid hormone were noted. Osteoid perimeter and area were significantly increased. The osteoid width significantly increased in both groups, but was twice higher in group II than I. At T45, the osteoblast perimeter increased in both groups. Osteoid perimeter was significantly correlated with serum osteocalcin values (r = 0.74; p less than 0.001) and bone fluoride content (r = 0.64; p less than 0.01). The bone formation rate at tissue level tended to increase in both groups. Concerning the apposition rate, a decrease was noted which was 1.5-fold higher in group II than in I. The increased formation period resulted from a prolonged inactive period in group II. These results point out a stimulatory effect of fluoride on the birth rate of osteoblasts. However, fluoride prolonged the lifespan of osteoblasts that had reduced activity.

Localization of endogenous osteocalcin in neonatal rat bone and its absence in articular cartilage: effect of warfarin treatment

Immunocytochemistry after cryoultramicrotomy was used to localize endogenous osteocalcin in bone (calvaria, femoral diaphysis) and epiphyseal femoral cartilage from 8-day-old rats treated (or mot) for 7 days with warfarin. Ultrathin frozen sections were incubated with goat antiserum against rat osteocalcin at high dilutions (2 x 10(-4) to 2 x 10(-6). In calvaria and femur of untreated rats, endogenous osteocalcin was observed in osteoblasts (cytoplasm and nucleus) and in the collagenous matrix. Osteocalcin appeared progressively in osteoblasts and bone matrix in the mineralization front, then increased in the regions of extended calcification. Osteocalcin was also detected in osteocytes but was not as abundant as in osteoblasts. In bone samples of warfarin-treated rats, endogenous osteocalcin was only detected in bone matrix but not in osteoblasts. Furthermore, osteocalcin was only observed if antiserum was not very dilute (2 x 10(-2). In cartilage (hypertrophied and degenerative zones), osteocalcin was not observed in matrix and chondrocytes. However, it was found in the vicinity of matrix vesicles at the initial loci of calcification. Osteocalcin was never detected in the cartilage of warfarin-treated rats. Our results provide ultrastructural immunocytological evidence for the localization of endogenous osteocalcin in osteoblasts, the presence of osteocalcin in bone matrix and a direct gradient between the presence of osteocalcin and the calcification process. Osteocalcin is absent from cartilage, except possibly close to calcifying matrix vesicles. Warfarin inhibits the formation of osteocalcin.

Comparison between radial bone mineral density measured by single photon absorptiometry and histomorphometric bone mass parameters measured on iliac crest biopsies

Bone mineral density (BMD) measured by single photon absorptiometry (SPA) with a Moolsgard 1100 device on the distal and proximal part of the radius was compared with histomorphometric parameters measured on iliac crest biopsies in 37 patients suffering from various bone disorders. In the whole population, a good correlation was observed between the cancellous bone volume (Cn-BV/TV) measured on iliac crest biopsies and BMD from both the proximal part of the radius (r = 0.76, p less than 0.001) and the distal part of the radius (r = 0.73, p less than 0.001). Significant, although weaker correlations, were also found between the cortical width and the BMD from the distal part (r = 0.37, p less than 0.001) and the proximal part (r = 0.44, p less than 0.001) of the radius. In the 14 untreated osteoporotic patients, only a significant Spearman correlation was observed between the iliac Cn-BV/TV and the proximal radial BMD (r' = 0.69, p less than 0.05). It is thus not clear, whether radial proximal BMD correctly indicates cortical bone density in osteoporotic patients or not. The large internal variability of each of the two investigated methods and the small group of osteoporotic patients might explain the lack of correlation between the two methods in this group.

Skeletal fluorosis: histomorphometric findings

Histomorphometric analysis of undecalcified sections was performed in transiliac biopsy cores taken from 29 patients (16 men, 13 women, aged 51 +/- 17 years) suffering from skeletal fluorosis due to chronic exposure to fluoride. The origin of the exposure, known in 20 patients, was either by water (endemic or sporadic), or industrial, or in a few cases iatrogenic. Measured on calcified bone using a specific ion electrode, bone fluoride content was significantly high in each specimen (mean +/- SD: 0.79 +/- 0.36% of bone ash) as compared to control values (less than 0.10%). The radiologically evident osteosclerosis observed in each patient was confirmed by the significant increase of cancellous bone volume (40.1 +/- 11.2 vs. 19.0 +/- 2.8% in controls, p less than 0.0001). There were significant increases in cortical width (1292 +/- 395 vs. 934 +/- 173 microns, p less than 0.0001) and porosity (14.4 +/- 6.4 vs. 6.5 +/- 1.7%, p less than 0.002), but without reduction of cortical bone mass. Osteoid parameters were significantly increased in fluorotic patients. The increase in cancellous osteoid perimeter was almost threefold greater than that noted in cancellous eroded perimeter. The fluorotic group had a greater number of osteoblasts than controls, with a very high proportion of flat osteoblasts. In 15 patients doubly labeled with tetracycline, the mineral apposition rate was significantly decreased, while mineralization lag time significantly increased. Bone formation rate and adjusted apposition rate were significantly decreased in skeletal fluorosis. Cancellous wall width was normal in fluorosis but the formation period and active formation period were significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a chronic GRF treatment on lambs having low or normal birth weight

The effects of a long term treatment with human GRF(1-29)NH2 on plasma growth hormone (GH), somatomedin C (Sm-C), histomorphometric parameters of bone growth and body composition were investigated in normal and low birthweight male lambs. The animals were divided into two groups according to their birthweight: 24 normal birthweight (NBW) lambs weighing more than 4 kg and 22 low birthweight (LBW) lambs weighing less than 2.5 kg at birth. Half of the animals in each group received two daily subcutaneous injections (8 micrograms/kg body weight) of hGRF(1-29) NH2 (GRF) from birth to slaughter at 45 or 90 days of age. The other animals received the solvent only. At the beginning and at the end of the treatment, plasma GH and serum Sm-C concentrations were measured in all groups. After slaughter, a histomorphometric study was performed on undecalcified sections of metacarpal growth plates, and the remaining of the carcass was pulverized to study the chemical body composition. GRF induced GH release in both GRF-treated groups. However, plasma GH reached higher (P less than .001) concentrations and the GRF-induced GH peak lasted longer in LBW than in NBW lambs. At day 45, the GRF treatment increased (P less than .05) serum Sm-C concentrations in LBW. Most of histomorphometric parameters reflecting the metacarpal growth in length, were not statistically modified under GRF treatment. However, the size of degenerative cells was smaller (P less than .05) in LBW treated lambs as compared to controls. Consequently, the cell production in the growth plate was increased (P less than .05) under GRF treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Osseointegration of metallic implants. II. Transmission electron microscopy in the rabbit

In a material of 10 osseointegrated implants of pure titanium, Tivanium, Vitallium, and stainless steel, 23 interface areas were studied by transmission electron microscopy. The implant site was the upper tibia of mature rabbits, and the observation time was 11 months. The absence of a cellular reaction was verified. However, even in cases of apparently uniform osseointegration, electron microscopy revealed an unpredictable variation in interface ultrastructure within 500-1,000 nm of the metal surface, common to all the materials. There was no structural feature that was specific for a particular material.

Experimental study of Cu-PbCl(2), Cu-NaF, Ag-PbCl(2), and Ag-NaF cermet thin films

We present in this paper the experimental spectral transmission curves of four different cermets, Cu-PbCl(2), Cu-NaF, Ag-PbCl(2), and Ag-NaF, as well as the calculated curves obtained from the generalized Maxwell-Garnett theory. The results show that the microstructure of the metal particles in the dielectric matrix is independent of the nature of the dielectric. We also show that this behavior is predicted by the generalized Maxwell-Garnett theory. However, our measurements also indicate that the microstructure is the same for both copper and silver cermets. This last experimental evidence cannot be explained within the context of the Maxwell-Garnett theory.

Skeletal fluorosis: histomorphometric analysis of bone changes and bone fluoride content in 29 patients

Bone fluoride content (BFC) was measured and histomorphometric analysis of undecalcified sections was performed in transiliac biopsy cores from 29 patients (16 men, 13 women, aged 51 +/- 17 years) suffering from skeletal fluorosis due to chronic exposure to fluoride. The origin of the exposure, known in 20 patients, was either hydric (endemic or sporadic) or industrial, or in a few cases iatrogenic. Measured on calcined bone using a specific ion electrode, BFC was significantly high in each specimen (mean +/- SD; 0.79 +/- 0.36% on bone ash). The radiologically evident osteosclerosis observed in each patient was confirmed by a significant increase in cancellous bone volume (40.1 +/- 11.2% vs. 19.0 +/- 2.8% in controls, p less than 0.0001). There were significant increases in cortical width (1292 +/- 395 mcm vs. 934 +/- 173 mcm, p less than 0.0001) and porosity (14.4 +/- 6.4% vs. 6.5 +/- 1.7%, p less than 0.002), but without reduction of cortical bone mass. Cancellous osteoid volume and perimeter, as well as width of osteoid seams, were significantly increased in fluorotic patients. The increase in cancellous osteoid perimeter was almost three-fold greater than that noted in cancellous eroded perimeter. In 15 patients doubly labeled with tetracycline, the mineral apposition rate was significantly decreased, mineralization lag time was significantly increased. The fluorotic group had a greater number of osteoblasts than controls with a very high proportion of flat osteoblasts. The ultrastructural characteristics reflecting the activity of the bone cells were clearly visible on electron microscopy. Bone formation rate and adjusted apposition rate were significantly decreased in skeletal fluorosis. On stained sections and microradiographs, bone tissue showed typical modifications for skeletal fluorosis (linear formation defects, mottled bone). The volume of cancellous interstitial mineralization defects and the proportion of mottled periosteocytic lacunae were markedly increased in skeletal fluorosis. These two parameters were significantly correlated together but neither of these was significantly correlated with BFC. Renal function did not significantly influence the changes in BFC and histomorphometry of fluorotic patients. Skeletal fluorosis is thus characterized by an unbalanced coupling in favor of bone formation, and a great number of osteoblasts with a high proportion of flat osteoblasts.(ABSTRACT TRUNCATED AT 400 WORDS)

Fluoride content in human iliac bone: results in controls, patients with fluorosis, and osteoporotic patients treated with fluoride

The major part of fluoride ingested is fixed on calcified tissues, mainly in bone tissue, and then is progressively but slowly recycled during bone remodeling. Thus, the measurement of bone fluoride content allows the determination of the extent of bone fluoride retention, and this parameter constitutes a useful complement to bone histology for the diagnosis of skeletal fluorosis and could also be used for the management of fluoride treatment of osteoporosis. A simple method is described to measure the fluoride content in calcined human iliac bone samples. Bone ashes were diluted in perchloric acid, and the measurement of the bone fluoride content was performed using a specific ion electrode combined with a reference electrode. Reference values are given for bone tissue from 76 control subjects (0.08 +/- 0.05% of bone ash), from two groups of 117 and 102 untreated osteoporotic patients (0.05 +/- 0.03% and 0.08 +/- 0.05%, respectively), from 166 sodium fluoride-treated osteoporotic patients (mean bone fluoride content varying from 0.24 to 0.67%, depending on the duration of therapy), and from 96 patients showing typical skeletal fluorosis (mean bone fluoride content varying from 0.56 to 1.33%, depending on the etiology of fluorosis and the relationship with the amount of fluoride ingested as well as with the duration of fluoride exposure). During a prolonged exposure of adult bone tissue to fluoride, the early bone fluoride uptake is variable and depends on the remodeling activity; then it increases rapidly before becoming more or less stable at a maximum level.

Comparison of bone mass measured by histomorphometry on iliac biopsy and by dual photon absorptiometry of the lumbar spine

In a prospective study we compared bone mass measured independently by dual photon absorptiometry (DPA) on lumbar spine and by histomorphometry on transiliac biopsy. Measurements were done in 83 patients (23 males, 60 females) with various generalized bone diseases, including spinal osteoporosis, primary hyperparathyroidism and osteopetrosis. Iliac bone density was analyzed on bone biopsy with an automatic image analyzer and expressed as the trabecular bone volume (TBV), the cortical thickness (CT) and the total bone density (TBD) which includes the density of both spongy and cortical bone within the periosteal envelope. The bone mineral content (BMC) and density (BMD) were measured from L2 to L4 with a Novo Lab 22a device. For the 83 patients, there were significant correlations between values given by both methods, with r values ranging from 0.74 to 0.43, according to the bone mass parameters analyzed. In the 37 patients with untreated vertebral osteoporosis, the TBV--but not the CT nor the TBD--correlated significantly with the BMD of the spine (r = 0.53, p less than 0.001). In conclusion, there is a significant correlation between bone density of the iliac crest assessed histomorphometrically and spinal density measured by DPA. Despite the fact that DPA measures both trabecular and cortical bone of the spine, it correlates better with iliac trabecular bone mass than with the overall iliac bone density.

Ultrastructural immunocytochemical localization of endogenous 1,25-dihydroxyvitamin D3 and its receptors in osteoblasts and osteocytes from neonatal mouse and rat calvaria

Immunoreactivity to 1,25-dihydroxyvitamin D3 receptors and endogenous 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) were studied in osteoblasts and osteocytes from calvaria of neonatal mice and rats by immunocytochemistry with the use of ultrathin sections obtained by cryo-ultramicrotomy. Tissue samples were fixed in glutaraldehyde, postfixed in osmium tetroxide and frozen under liquid nitrogen. 1,25(OH)2D3 and 1,25(OH)2D3 receptor-like immunoreactivities were observed in osteoblasts and osteocytes. In both types of cell, 1,25(OH)2D3 and its receptors were similarly located in the cytoplasmic matrix but not in organelles, and mainly in the nucleus (primarily in the chromatin and sometimes near the nuclear membrane or in the nucleolus). Reaction products, however, were never seen at the plasma membrane level. These results provide immunocytological evidence for the presence of 1,25(OH)2D3 and its receptors in osteoblasts and osteocytes. The similar localization of the hormone and its receptors in osteoblasts and osteocytes supports the hypothesis of a direct action of 1,25(OH)2D3 in these bone cells. The fact that the main localization of 1,25(OH)2D3 receptors was nuclear, implies, as postulated for other steroid receptors, that 1,25(OH)2D3 receptors occur primarily in the nucleus.

Synthesis of gradient-index profiles corresponding to spectral reflectance derived by inverse Fourier transform

Inverse Fourier transform has been used to derive the gradient-index profiles of inhomogeneous films having spectral requirements. Two examples are given, and the corresponding experimental designs are presented. Results show a good agreement with the theory and evidences the reliability of the technology used to produce inhomogeneous media.

Deferoxamine-induced bone changes in haemodialysis patients: a histomorphometric study

1. The histological effects of deferoxamine therapy were assessed on transiliac bone biopsies taken after double tetracycline labelling from 16 uraemic patients undergoing chronic haemodialysis, all having aluminium deposits in bone. Eight patients had osteomalacia, five had an "aplastic" bone lesion and three a high bone turnover with a marked increase in osteoid volume. 2. Deferoxamine was administered intravenously once a week at doses ranging from 1 to 6 g for a mean duration of 7.6 +/- 3.3 (SD) months. 3. Deferoxamine therapy was associated with significant reductions in stainable aluminium deposits, osteoid volume, osteoid surfaces and thickness index of osteoid seams. The osteoblastic osteoid surfaces as well as the bone formation rates also increased significantly. 4. A rise in resorption parameters and in serum parathyroid hormone levels was observed in patients with osteomalacia. The percentage reductions in stainable aluminium and in osteoid volume were correlated with the degree of hyperparathyroidism. 5. These data show that deferoxamine therapy reduces stainable bone aluminium and improves bone mineralization in low turnover osteomalacia and that the presence of hyperparathyroidism is associated with an increased response to deferoxamine therapy.

Ultrastructural study of the long-term development of two experimental cutaneous calcinoses (topical calciphylaxis and topical calcergy) in the rat

Skin calcification induced by topical calciphylaxis was provoked by a subcutaneous injection of iron chloride in rats previously sensitized by dihydrotachysterol. A cutaneous topical calcergy was induced by an injection of potassium permanganate. An electron-microscopical study of the long-term evolution of both these models of calcification was made. After the initial stages, mineralization of the connective tissue continued by a secondary nucleation process without matrix vesicles. The mineral composed of needle-like structures, apatite in nature, was mainly deposited between and around collagen fibrils, and showed various arrangements in calcified plaques. Intrafibrillar calcification was rarely observed and appeared only in the later stages. The extension of calcified deposits then stopped. Finally, there was a fragmentation of the mineralized area which was progressively surrounded by uncalcified collagen fibrils. A demineralization process, caused by cells such as macrophages and multinucleated giant cells, rather than a resorption of the calcified deposits, was noted. It is important to emphasize that, in both models of ectopic calcification, an evolution toward ectopic ossification was never observed, which is perhaps due to the absence of extensive resorption mechanisms.

[Effects of isoflurane on bleeding in microsurgery of the middle ear]

40 patients undergoing middle ear microsurgery were anaesthetized with a narconeuroleptanalgesia (droperidol, phenoperidine, thiopentone) associated with a randomly selected halogenated volatile anaesthetic, either halothane or isoflurane at a concentration of 1 MAC. Clinical and haemodynamic tolerance was perfect. Respiratory and haemodynamic parameters were not significantly different in either series at the different moments that were common to all the operations. There was less bleeding in the isoflurane group, and it was stable (p less than 0.01). Isoflurane would seem to have the double advantage of maintaining anaesthesia and producing a bloodless surgical field, so avoiding the use of added hypotensive agents.

Adult sporadic hypophosphatemic osteomalacia presenting as regional migratory osteoporosis

Osteoarticular manifestations associated with adult sporadic renal phosphate diabetes have previously been reported. We describe a 36-year-old man with phosphate diabetes who presented with migratory regional osteoporosis of the lower limbs. Our data suggest a cause-effect relationship between regional migratory osteoporosis and adult phosphate diabetes.

[Histomorphometric profile of bone fluorosis induced by prolonged ingestion of Vichy Saint-Yorre water. Comparison with bone fluorine levels]

Nine transiliac bone biopsies from 7 patients with skeletal fluorosis due to prolonged ingestion of often high quantities of Vichy Saint-Yorre water were analyzed. Four of these patients also suffered from a chronic renal failure. A histomorphometric study was possible in 8 out of the 9 biopsies. The measurement of bone fluoride content, and a microradiographic examination, were performed on all bone samples. The radiologically evident osteosclerosis observed in each patient was confirmed by the significant increase of trabecular bone volume. Furthermore, the osteoid surfaces were very extended but the thickness of osteoid seams was normal in 6 out of 8 cases. Two biopsies demonstrated a morphological evidence of osteomalacia with abnormally thick osteoid seams. Calcification rate, measured in one of these 2 cases after tetracycline double labeling, was extremely low (less than 0.20 micron/d). The bone fluoride content was significantly high in each specimen (greater than 0.40 bone ash%) and correlated with relative osteoid volume (r' = 0.91) and thickness index of osteoid seams (r' = 0.83). Histologically, bone tissue showed modifications classically reported in the various types of skeletal fluorosis (formation defects, mottled bone with mottled periosteocytic lacunae). In conclusion, the prolonged administration of Vichy Saint-Yorre water containing 8.5 mg of fluoride ion per liter, provokes a skeletal fluorosis. This intoxication appeared very quickly if the patient suffered from an even mild renal failure. Once again, it is shown that a disturbed renal function predisposes to an excessive retention of fluoride.

[Multidisciplinary study of the prolonged treatment of involution osteoporosis using sodium fluoride with calcium, phosphate and vitamin D]

A multidisciplinary study on the prolonged treatment of involution osteoporosis with fluoride was performed on a homogeneous population of 31 women aged 51 to 75 years (mean 64 years). The selection criteria were the following: significant backache, vertebral compression fractures on X-rays, bone biopsy evidence of osteoporosis, and absence of other risk factors after a complete workup. The patients were treated for a period of 3 to 6 years (mean 4 years) with daily doses of 30 mg (10 mg 3 times) fluorides ion associated during the last 3 years with 500 mg calcium twice daily, 750 mg phosphate and 1000 units vitamin D daily. The study demonstrated a favourable effect of the treatment on the backache and that it was well tolerated in the majority of cases, the side effects being intermittent osteo-articular pains of the lower extremities due to the fluoride in 9 patients, and gastric intolerance to the phosphate in 7. X-ray follow-up showed slowing of the vertebral compressions after the first year of treatment, but no effect on fractures of the extremities. There was no evidence of alterations in parameters of mineral and bone metabolism, and in endocrine, hepatic, renal or hematological assays. Histomorphometric and biophysical examination of biopsies indicated that, although there was no significant increase in the quantity of mineralized bone under the treatment, there was a very significant improvement in the crystallinity of the mineral substance, thus enhancing the quality of the bone tissue and its resistance to pressure. This study is the first in which a catamnesis of the patients was undertaken, 28 of them having received a clinical and radiological examination 2 years after the end of therapy: a favourable evolution was observed in most of the cases, both in those patients treated for a period of 3 years and in those whose treatment had lasted for a longer period.

Susceptibility of the Carrot Weevil (Coleoptera: Curculionidae) to Steinernema feltiae, S. bibionis, and Heterorhabditis heliothidis

Larvae, pupae, and adults of the carrot weevil (Listronotus oregonensis) were infected and killed by the three entomophagous nematodes (Steinernema feltiae, S. bibionis, and Heterorhabditis heliothidis) under controlled conditions. Third-stage larvae were more susceptible than pupae or adults. S. feltiae and S. bibionis were the most aggressive nematode species, causing larval mortality after 24-48 hours in both continuous and 2-hour contact with nematode suspension. The nematodes multiplied sufficiently in all insects at all stages of development; however, production of infective-stage larvae per host cadaver was variable.

Immunocytochemical evidence for endogenous calcitonin and parathyroid hormone in osteoblasts from the calvaria of neonatal mice. Absence of endogenous estradiol and estradiol receptors

Immunoreactivities to endogenous calcitonin, endogenous parathyroid hormone, endogenous estradiol and estradiol receptors were studied in osteoblasts from the calvaria of neonatal mice by immunocytochemistry with the use of ultrathin sections obtained by cryo-ultramicrotomy. Tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and frozen in liquid nitrogen. Estradiol and estradiol receptors could not be detected in osteoblasts, whereas calcitonin- and parathyroid hormone-like immunoreactivities were observed in this cell type. Calcitonin and parathyroid hormone had similar subcellular localizations: immunoreactivities were observed at the plasma-membrane level, in the cytoplasmic matrix, and in the nucleus. These results provide immunocytological evidence for: 1) the internalization of calcitonin and parathyroid hormone in osteoblasts; 2) a direct participation of calcitonin and parathyroid hormone in the regulation of osteoblasts; 3) the absence of estradiol receptors and estradiol in osteoblasts.

Distribution of fluoride in calcified cartilage of a fluoride-treated osteoporotic patient

Subchondral bone and calcified cartilage from a femoral head of a 74-year-old osteoporotic woman treated for 30 months with sodium fluoride were analyzed. The fluoride content of the calcified tissues was determined by a specific ion electrode, and the topographic distribution pattern of fluoride was determined with an electron microprobe. The fluoride content in calcified cartilage (0.39% of ash) was higher than in neighboring subchondral bone (0.28% of ash). Line scan and X-ray images indicated a high concentration of fluoride in the outer layer of calcified cartilage lining the uncalcified cartilage, as well as in the inner layer of the subcortical endosteal bone. This study shows that calcified cartilage is an important site of fluoride deposition, and suggests that the accumulation of fluoride is related to the calcification process.

Histological study of a case of recurrent olecranon bursitis with mixed calcium pyrophosphate dihydrate and apatite crystal deposits

This is the report of a light and transmission electron microscopic study of an olecranon bursitis and of the adjacent distal tricipital tendon in an 83 year-old man. The data are compared with those of a similar study in the same patient performed 2 years ago. Calcium pyrophosphate dihydrate crystals were observed in the bursal fluid, in the inner part of the bursal wall (extracellular localization and intracellular phagocytosis) as well as in the peripheral part of the tendon. In addition, small apatite deposits were observed in the bursa and tendon by electron microscopy. The origin of these bursal deposits is discussed; it is suggested that they may be related to an exchange from the tendon to the remodelled bursal wall.

Influence of surface effects in the determination of the optical constants of Cu-PbI2 cermet films

The determination of optical constants of thin film Cu-PbI 2 cermets using a photometric method has shown an unexpected variation of the results with respect to the thickness of the film. These effects are analyzed in detail in this paper. To understand the origin of this discrepancy an alternate method of determination of optical constants has been set up by using a new double-slit interferometer. This method, quite general and particularly well adapted for the study of absorbing films, allows the elimination of the surface effects and retains only the contribution from the volume optical constants of the films. Results from both methods are compared and they show that the surface effects are practically negligible for relatively thin films (d = 25 nm).

Ultrastructural aspects after cryoultramicrotomy of bone tissue and sutural cartilage in neonatal mice calvaria

Using transmission electron microscopy after cryoultramicrotomy, mineralized as well as unmineralized bone tissues and sutural cartilage were observed in neonatal mice calvaria. A good definition of osteoblasts (nucleus, membranes, organelles) and extracellular constituents (collagen fibrils, matrix vesicles, mineral substance) was obtained. The sutural zone was composed of an unmineralized cartilaginous tissue with more or less hypertrophic cells surrounded by a finely fibrillar matrix.

Is a certain degree of osteomalacia involved in femoral neck fractures of the elderly? Histological approach to the problem and practical applications

A study was made in Geneva of 14 patients with femoral neck fractures (7 subcapital and 7 trochanteric) to determine whether a certain degree of osteomalacia might be involved (group I). No patients with risks factors for osteomalacia were used. For ethical reasons, double tetracycline labelling was not possible and osteomalacia criteria were based on osteoid tissue values determined in a histomorphometric study directly on cancellous bone samples of the femoral head. A comparison was made with femoral head bone tissue taken from 12 patients with hip osteoarthritis at a distance from the remodelled territory (group II) and with iliac crest bone tissue taken from 6 patients with clinically and biochemically determined osteomalacia (group III). The patients were part of a larger group of subjects used for a biochemical blood study in which levels of albumin, calcium and 25 OHD3 as an index of vitamin D content were determined. Based on the data of the literature and the results obtained for group II, slight signs of osteomalacia were diagnosed for only one case (group I), although 25 OHD3 deficiency was found in more than a third of the subjects in that group as well as in some subjects of group II and in some of the aged controls. Skeletal aging must be considered not only in terms of unavoidable physiological factors but also within the context of living conditions. Hence the necessity of controlling calcium and vitamin D intake in the elderly, and of a histological examination for signs of osteomalacia in surgical specimens from patients with femoral neck fractures.

Bilateral fractures of femoral neck in patients with moderate renal failure receiving fluoride for spinal osteoporosis

Two patients with moderate renal failure sustained spontaneous bilateral hip fractures during treatment with fluoride, calcium, and vitamin D for osteoporosis. They had been taking sodium fluoride (40-60 mg/day) for 11 and 21 months, respectively. Histological examination of a specimen of the bone showed severe fluorosis in the first case, and quantitative analysis of bone showed osteomalacia and skeletal fluorosis in the other case. These abnormalities were considered to be the consequence of excessive retention of fluoride due to renal insufficiency. As bilateral femoral neck fractures are very rare these data suggest a causal link between fractures and fluoride in patients with renal failure. Thus fluoride should be given at a lower dosage, if at all, to patients with even mild renal failure.

Calcergy and calciphylaxis: timed appearance of gamma-carboxyglutamic acid and osteocalcin in mineral deposits

gamma-Carboxyglutamate (Gla), a calcium binding amino acid whose synthesis depends on vitamin K, has been found in association with pathologic calcifications. It is of interest therefore to examine the role of Gla-containing proteins in the formation of nonskeletal mineralized tissues. Calcergy and calciphylaxis, experimentally induced models of pathologic calcification, offer the opportunity to study the formation of mineral deposits in the absence of an endochondral sequence of bone formation. Before induction of subcutaneous calcinosis by topical treatment with the direct calcergen, KMnO4, or by challenging dihydrotachysterol-sensitized animals with FeCl2, control specimens contain no gamma-carboxyglutamic acid. With the initial formation of cytoplasmic vesicles, calcium content of the tissues increases and Gla is detected. Gla levels are further elevated with the appearance of poorly crystalline apatite-like crystallites. Origin of protein bound Gla was established by positive identification of osteocalcin by radioimmunoassay. Gla and osteocalcin appear concomitant with the earliest mineral deposits observed by electron microscopy and micro X-ray analysis. The formation of organized extracellular pattern by X-ray diffraction allowed sufficient mineral accumulation for detection with calcium, Gla, and osteocalcin increasing allowed sufficient mineral accumulation for detection of an apatite-like pattern by X-ray diffraction with calcium, Gla, and osteocalcin increasing proportionately as mineral is deposited.