Histomorphometric bone modifications induced by growth hormone treatment in a rabbit model of short bowel syndrome

The effects of recombinant human growth hormone (rhGH) on cancellous and cortical bone were investigated in an experimental rabbit model of short bowel syndrome (SBS). Eighteen young male New Zealand rabbits, 2.0 +/- 0.2 kg b.w., were divided into three groups: an SBS Group submitted to a 70% midjejunoileal enterectomy and reanastomosis; an SBS-GH Group undergoing the same surgery and receiving 0.4 mg/kg/day rhGH for 28 days; a Control Group which was sham-operated. Thirty-five days after surgery, all the animals were pharmacologically euthanised and their femurs and L5 vertebrae were used for densitometric and histomorphometric studies. Vertebral and femoral densitometric results showed that the SBS Group presented significantly (P<0.01) lower values (10-25%) than the Control and SBS-GH Groups. Significant differences in the cancellous histomorphometric parameters, namely the trabecular bone area (-7% to 46%), trabecular thickness (-21% to 34%) and trabecular separation (17-32%), were observed between the SBS Group and the other groups. Both the SBS and SBS-GH Groups showed significantly (P<0.05) higher values than the Control Group in terms of cross-sectional area (approximately 24%), cortical area (approximately 20%), and periosteal perimeter (approximately 9%), while medullary area (41%) and endocortical perimeter (18%) were significantly higher (P<0.05) in SBS Group than those of Control Group. The current findings are encouraging and suggest that GH administration in SBS animal model used may improve skeletal tissue remodelling.

Spectral analysis of skin laser Doppler blood perfusion signal during cutaneous hyperemia in response to acetylcholine iontophoresis and ischemia in normal subjects

Spectral analysis of skin laser Doppler (LD) signal was performed using Fourier transformation in twelve healthy subjects in order to compare post-ischemic hyperemia and acetylcholine (ACh) iontophoresis tests for the exploration of cutaneous microcirculatory endothelial function. Within the frequency range studied of 0.009-1.6 Hz, five different frequency intervals were considered, arising from local (endothelial and myogenic) and central (neural, respiratory and cardiac) regulatory mechanisms. The power density (PD) for each of the five frequency intervals considered was measured in perfusion units (PU)/Hz, in each subject, before and in response to ischemia and to ACh iontophoresis, using a dedicated software. The relative contribution of each frequency interval was calculated as per cent rate between each PD and the sum of the PD of the five frequency interval considered. PD of LD signals in response to ischemia and Ach iontophoresis significantly increased for all the five frequency intervals considered. A significant increase (from 25.0+/-6.3 to 48.3+/-17.8; p<0.01) in the relative contribution of 0.009-0.02 frequency interval, referred to endothelium activity, was observed only in response to ACh iontophoresis. No significant increase in the relative power contribution was observed in response to ischemia for any of the five frequency intervals considered. These data suggest that ACh iontophoresis test is more adequate than post-ischemic hyperemia test in exploring the skin microcirculatory endothelial function in normal subjects.

Advanced breast cancer: an update and controversies on diagnosis and therapy

This review on advanced breast cancer considered important differences in the actual definition of this condition. Advanced breast cancer includes locally advanced, locoregionally recurrent and metastatic disease, which have different diagnosis, prognosis and therapy; their actual definitions are relatively uncertain. Differently from the common opinion that metastatic breast cancer (MBC) is a very severe incurable disease, recently it has been reported that a small but not irrelevant fraction of MBC patients can be cured or remain in long-term survival with complete remission. The type of metastases of the population studied in these reports was analysed and the authors hypothesised that the particularly high DFS reported mainly was attributable to the high proportion of patients with locoregional metastases only. Furthermore, the options and associations of the drug therapy available for treatment of advanced breast cancer have been reviewed.

“Tumour marker guided” salvage treatment prolongs survival of breast cancer patients: final report of a 7-year study

OBJECTIVES

Randomised trials on breast cancer showed no significant benefit from post-operative follow-up with clinical and/or conventional radiological means. We hypothesised that carcinoembryonic antigen (CEA), tissue polipeptyde antigen (TPA), breast cancer associated antigen 115 D8/DF3 (CA15.3) tumour marker panel is sensitive enough for significantly anticipating salvage treatment and prolonging survival of relapsing breast cancer patients.

METHODS

From October 1981 to May 1999, 68 (62%) of 109 patients with distant metastases were recruited. Thirty-six (53%) received salvage treatment at the time of significant increase in one or more components of CEA-TPA-CA15.3 tumour marker panel and negative instrumental examinations ("tumour marker guided" treatment) and 32 (47%) were treated only after radiological confirmation of metastases (conventional treatment). The prognostic factors of the two groups did not show any statistically significant difference.

RESULTS

The time from one or more tumour marker increase to clear clinical and/or radiological signs of distant metastases (lead time) was significantly prolonged in the 36 patients with "tumour marker guided" treatment (17.3 +/- 13.1 vs. 2.9 +/- 2.9 months, P < 0.001, Wilcoxon test) as well as the survival curves from salvage therapy and from mastectomy (the proportion of survivors was: at 36 months from salvage therapy 28% vs. 9%, P = 0.0094; at 84 months from mastectomy 42% vs. 19%, P = 0.0017). The multivariate Cox analysis showed that time from mastectomy to tumour marker increase and "tumour marker guided" salvage treatment were the only significantly different variables (P = 0.00001 and 0.005, respectively).

CONCLUSION

These data point out that "tumour marker guided" salvage treatment significantly prolongs disease-free and overall survivals of relapsing responsive patients.

Nonpalpable thyroid carcinoma: clinical controversies on preoperative selection

This article emphasizes some controversies concerning the preoperative selection of nonpalpable thyroid tumors. The prevalence of occult thyroid carcinoma in surgical series (1.8-10%) is not higher than in autopsy thyroid series (2.7-24%). The prevalence of occult thyroid carcinoma in thyroid glands examined in the same institution by ultrasound, for a clinical thyroid abnormality or for investigation of other neck structures without clinically evident or suspected thyroid disease, varies from 3% to 8% and is very similar independent of the fact that a thyroid abnormality is or is not the indication for ultrasonography. These data suggest that the presence of a thyroid disease is not a risk factor for harboring an occult thyroid carcinoma (except for C-cell hyperplasia in the rare case of MEN 2 syndromes). As it is not cost effective to examine all the nonpalpable lesions with fine-needle aspiration (FNA) guided by ultrasounds, it is necessary to define to which extent ultrasound is useful in selecting those lesions to be examined cytologically by FNA. The use of ultrasound to select these lesions is very controversial. Ultrasound-guided cytologic diagnosis of nonpalpable nodules is not as accurate as in the case of palpable nodules. Sampling of material adequate for cytologic analysis depends on the lesion size; it is 64% for a 0.7-cm lesion and it increases to 86.7% for a mean size of 1.1 cm. For the diagnosis of occult thyroid carcinomas (< or =1 cm), sensitivity is 35.8% and false-negative results are 49.3%. Nonpalpable nodules with a size of 1.5 cm represent an absolute indication to perform an ultrasound-guided FNA because this is the size limit for dividing thyroid nodules in probably innocuous or potentially dangerous categories and because the cytologic diagnosis of nodules of this size is sufficiently reliable. For the smaller incidentally discovered thyroid nodules following ultrasound, physicians should discuss with the patient whether and when to perform an ultrasound-guided FNA considering the patient's data (risk factors, age, health state, etc.), the natural history of a small thyroid carcinoma, as well as the accuracy of ultrasound and ultrasound-guided FNA in the specific institution.

Comparative interspecies investigation on osteoblast cultures: data on cell viability and synthetic activity

The aim of the present study was to evaluate and compare the most common parameters that characterize the expression of primary osteoblast cultures from different origin (human, rat, sheep), and of the human osteosarcoma cell line MG-63 before and after stimulation with vitamin 1,25(OH)(2)D(3). Cell viability was quite similar for primary osteoblast cultures (MTT: 1.64-2.11 OD); a significant (P < 0.005) difference was found between sheep osteoblasts and MG-63 (DeltaMTT: 0.52 +/- 0.20 OD). Osteocalcin synthesis ranged from 15.18 to 27.00 pg/ml in primary osteoblast cultures, while it was significantly (P < 0.01) lower in MG-63 (OC: 6.67 +/- 0.52 pg/ml) when compared with primary human osteoblasts. Alkaline phosphatase, C-terminal procollagen type I, and interleukin-6 were significantly (P < 0.005) lower in rat osteoblasts when compared with primary human osteoblasts, and similarly transforming growth factor-beta1 was significantly (P < 0.05) lower in rat and sheep osteoblasts when compared with primary human osteoblasts and MG-63. Nitric oxide synthesis did not show any significant difference either before or after vitamin 1,25(OH)(2)D(3) stimulation. In conclusion, the current findings confirm the presence of interspecies differences between the selected osteoblast lineages before and after stimulation with vitamin 1,25(OH)(2)D(3). Above all, the culture of sheep osteoblasts was seen to behave more similarly to that of primary human cells, mainly in terms of cell viability, osteocalcin, interleukin-6 and transforming growth factor-beta1 production.

Surface chemistry effects of topographic modification of titanium dental implant surfaces: 1. Surface analysis

PURPOSE

To analyze the surface composition of 34 different commercially available titanium dental implants.

MATERIALS AND METHODS

Surface composition was evaluated by x-ray photoelectron spectroscopy (XPS). Samples were divided into 4 groups, depending on their surface topography (machined, sandblasted, acid etched, or plasma sprayed).

RESULTS

Statistical analysis of the data showed a clear relationship between surface composition and topography, which can be easily accounted for by the chemical effects of the surface treatment performed. On average, acid-etched and plasma-sprayed surfaces had higher titanium and lower carbon concentration than machined surfaces.

DISCUSSION AND CONCLUSION

Current studies aimed at the evaluation of implants with different topography should not implicitly assume that topography is the only variable controlling the biologic response. Rather, when comparing different topographies, it should be taken into account that surface chemistry may be a variable as well.

Surface chemistry effects of topographic modification of titanium dental implant surfaces: 2. In vitro experiments

PURPOSE

To determine, in vitro, cytotoxicity and cell adhesion on 3 different implant surfaces.

MATERIALS AND METHODS

All samples had machined surfaces, but they were subjected to different cleaning procedures, which produced 3 different surface chemistries. One of the samples was "as-produced" from the machining tools. The other samples were subjected to partial and total cleaning routines. Cytotoxicity was evaluated using mouse fibroblast cultures, and cell adhesion was evaluated with osteoblast-like SaOS-2 cells.

RESULTS

The "as-produced" sample showed a pronounced surface contamination by lubricating oils. For partially and totally cleaned samples, an increasing amount of titanium and a decreasing carbon/titanium ratio was observed as cleaning became more complete.

DISCUSSION

Differences in surface chemistry such as those normally found on titanium implant surfaces (see part 1 of this series) can lead to those same effects which, in in vitro experiments, are normally accounted for in terms of surface topography alone.

CONCLUSION

Effects related to surface chemistry can operate over and above surface topography, making it impossible, without proper characterization, to make definite statements about the role of topography alone.

L-arginine and L-lysine stimulation on cultured human osteoblasts

Essential amino acids, such as L-Arginine (Arg) and L-Lysine (Lys), are involved in bone metabolism and growth. Our previous studies analyzed the effect of these amino acids on rat osteoblast cultures and in experimental animals. In this study, we evaluated the effect of L-Arg and L-Lys on cultured human osteoblasts. Primary human osteoblast cultures were divided into four groups: the Arg Group received 0.625 mg/ml per day of Arg, the Lys Group 0.587 mg/ml per day of Lys, the Arg-Lys Group received both amino acids, whereas the Control Group was sham-treated. After 7 days, the following parameters were tested in all groups: alkaline phosphatase (ALP), nitric oxide (NO), calcium (Ca), phosphorus (P), osteocalcin (OC), type I collagen (PICP), interleukin-6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1) on culture supernatant, platelet derived growth factor (PDGF), insulin-like growth factor-I (IGF-I), and MTT proliferation test on cells. Arg administration significantly increased ALP, NO, PICP and IGF-I production and reduced the level of IL-6. Lys administration over the same time interval mainly affected cell proliferation, as evidenced by the MTT test and immunostaining for PDGF. The same positive effects evidenced by the single administrations of the two amino acids resulted from their simultaneous administration. However, synergism could be demonstrated only for the decrease in the level of IL-6. Arg and Lys show a positive effect on human osteoblasts, which is related partly to the production of those factors required for matrix synthesis, and partly to the direct or mediated activation of cell proliferation.

Controlling the lateral distribution and alignment of human gingival fibroblasts by micropatterned polysaccharide surfaces

Adhesion and alignment of primary human gingival fibroblast to Petri dishes were controlled by proper modification of the surface chemistry of the solid substrate. In particular, air plasma (glow-discharge) treatment, coupled to a masking technique, was used to pattern cell-adhesive areas on a cell-adhesion-resistant alginate coated surface. Fibroblasts were successfully confined to the air plasma-treated areas, which show a much greater growth rate and cell density as compared to the original alginate coated surface. Beside the implications for the study of the mechanisms of bio-adhesion at hydrophilic surfaces, these systems can be of interest for a number of applications in dental surgery and materials.

Spermatogenesis in azoospermic, formerly cryptorchid men. Use of needle aspiration techniques

OBJECTIVE

To assess the use of testicular needle aspiration techniques to evaluate fertility potential in azoospermic, formerly cryptorchid men.

STUDY DESIGN

Fifteen consecutive adult azoospermic, formerly cryptorchid patients (eight unilateral and seven bilateral) were examined by needle aspiration techniques, fine (FNA) and large needle (LNAB) testicular aspiration biopsy, for cytologic and histologic analysis. Five of the 15 subsequently underwent surgical biopsy for attempted assisted fertilization.

RESULTS

Spermatozoa or spermatids were detected by FNA cytology or LNAB histology in one or both testicles in 87.5% of the unilateral and 28.6% of the bilaterally affected, formerly cryptorchid patients (P = .041, Fisher's exact test). The addition of LNAB to FNA identified spermatids in one patient with unilateral cryptorchidism and only Sertoli cells on FNA cytology. Furthermore, LNAB differentiated testicles with the cytologic finding of only Sertoli cells into those with or without diffuse fibrosis. In the five patients in whom assisted fertilization was attempted, the needle aspiration techniques predicted the presence or absence of spermatozoa in the subsequent surgical biopsy.

CONCLUSION

The two needle aspiration techniques can be used to assess the fertility potential of azoospermic, formerly cryptorchid men and to select patients for assisted fertilization.

Atherosclerosis and cancer: common pathways on the vascular endothelium

This article reviews experimental and clinical data on atherosclerosis and cancer showing common pathogenic mechanisms. It is suggested that common pathways follow dysfunction of the vascular endothelium. The activation of the haemostatic system and the overexpression of cytokines and adhesion molecules by the endothelial cells represent important features of this dysfunction. These mechanisms can be responsible for progression of both diseases and explain the higher incidence of thromboembolic events in cancer patients, the occurrence of similar laboratory findings and the effect of many drugs on the course of the two diseases. Our article confirms that atherosclerosis and cancer share common mechanisms, and we hope it will stimulate further clinical trials on the use of drugs active on the haemostatic system in cancer patients.

Phalangeal ultrasonography in forearm fracture discrimination

Over the last decade, the use of ultrasounds has been developed into an effective tool for investigating bone tissue and predicting the risk of fracture in osteoporosis. Studies have focused on hip and vertebral fractures while no information is available on the use of phalangeal ultrasonography to identify patients with forearm fractures. Thus, the current authors decided to compare 50 postmenopausal women with low energy forearm fractures (Fractured Group) with a control age-matched group of 94 women (Control Group). Measurements were taken at the distal metaphysis of the proximal phalanxes of the hand of the non-fractured arm using the DBM Sonic Bone Profiler. The reproducibility of the method was assessed by amplitude-dependent speed of sound (AD-SoS) CV% = 0.64 and by Ultrasound Bone Profiler Index (UBPI) CV% = 2.38. In the Control Group, the AD-SoS and UBPI mean values and standard deviations were significantly higher compared to the group with fractures (P < 0.0005). The receiver operating characteristic (ROC) curves were calculated and the areas under the curve (AUC) were 0.78 +/- 0.04 for AD-SoS and 0.77 +/- 0.05 for UBPI, respectively. Logistic regression analysis adjusted to age revealed that both AD-SoS (78.2%, ORAD-SoS = 12.03, P < 0.0005) and UBPI (76.0%, ORAD-SoS = 7.39, P < 0.0005) parameters discriminated correctly between fractured and non-fractured control women whereas the association of both parameters could not allow better discrimination. The present results showed that ultrasound investigation at the phalanxes is reproducible and efficiently discriminates between subjects with forearm fractures and those in the control subjects.

Long-term monitoring of cell-mediated immunity in disease-free breast cancer patients: a preliminary retrospective study

In 102 N- and 44 N+ disease-free breast cancer patients, lymphocytic populations and skin reaction of delayed hypersensitivity (SRDH) were monitored up to 266 months after mastectomy to find out whether they were similar or different from control values. In two selected groups of 34 N- and 11 N+ breast cancer patients, the whole 10 year follow-up was divided into three subintervals, each of them lasting 40 months and the time course of lymphocytic populations was evaluated. In the 102 N- patients, mean CD4+, CD8+, CD3+ values were lower (P < 0.01, P < 0.001, P < 0.01, respectively) while CD4+/CD8+ ratio was higher (P < 0.05) than in controls. Fifteen N- breast cancer patients (16%) were anergic compared to 30(32%) of controls (P < 0.05). In the 34 selected N- breast cancer patients soon after mastectomy the mean value of CD4+, CD8+, CD3+ T subpopulations was lower (P < 0.01, P < 0.001, P < 0.01, respectively) than in controls. Successively their mean value increased so that in the last subinterval they were not or were only slightly lower (P n.s., P < 0.05, P < 0.05, respectively) than in controls. In the 44 N+ patients, mean CD4+, CD8+, CD3+ values were lower (P < 0.001, v < 0.05, P < 0.01, respectively) and CD19+ lymphocytes higher (P < 0.001) than in controls. Five N+ breast cancer patients (13%) were anergic compared to 32% of controls (P < 0.05). In the 11 selected N+ breast cancer patients soon after mastectomy, the mean value of CD4+, CD8+ T subpopulations and CD16+56+ cells was significantly lower (P < 0.001, P < 0.001, P < 0.01, respectively) than in controls. Successively their mean value constantly increased so that in the last subinterval, no or slight (P n.s., P < 0.05, P n.s., respectively) significant difference compared to controls occurred. The mean CD4+/CD8+ ratio value of N- patients was significantly higher than in controls. However in the last subinterval, the significance was lower than in the first one (P < 0.05 and P < 0.01, respectively). In the N+ patients, the mean value of CD4+/CD8+ ratio was constant, although not significantly, lower than in controls; however it progressively increased from the first to the last subinterval. Therefore the significance of the difference of the mean CD4+/CD8+ ratio between N- and N+ patients strongly decreased from the first to the last subinterval (P < 0.001 and P < 0.05, respectively). These data indicate that in breast cancer patients, following mastectomy, a significant activation of memory and CD4+ T cells and long-term decrease of the circulating immunocompetent CD4+, CD8+ and CD16+56+ cells occurs. The prolonged disease-free interval observed in the 34 N- and 11 N+ breast cancer patients can be correlated with the restoration of the normal state of cell-mediated immunity.

Large-needle aspiration biopsy for the preoperative selection of follicular adenoma diagnosed by fine-needle aspiration as a microfollicular nodule or suspected cancer

The preoperative fine-needle aspiration (FNA) cytologic diagnoses of microfollicular nodule and suspected cancer include nodules that yield histologic results of typically benign lesions, nodular hyperplasia and follicular adenomas, and differentiated thyroid cancer postoperatively. We reviewed the clinical and pathologic data for patients with palpable thyroid nodules with these two cytologic diagnoses; nodules were also examined by large-needle aspiration biopsy (LNAB) to assess whether the distinction achieved by LNAB in pure microfollicular or mixed microfollicular-macrofollicular nodules could be used preoperatively to better predict the diagnosis of follicular adenoma. One hundred fourteen nodules of this type were excised. Postoperative results were grouped in nodular hyperplasia (90 nodules), follicular adenoma (8), and differentiated carcinoma (16). The prevalence of the follicular adenoma and thyroid carcinoma postoperative findings was 33% among the microfollicular nodules and 5.9% among the microfollicular-macrofollicular nodules at preoperative LNAB, (p = 0.0004). Within the postoperatively benign nodules, the prevalence of follicular adenoma was 14.3% among the microfollicular nodules and 2% among the microfollicular-macrofollicular nodules at LNAB (p = 0.028). These data indicate that histologic examination of the LNAB specimen can be used to identify those thyroid nodules diagnosed by FNA as microfollicular nodules or suspected cancer, which are most likely to be follicular adenomas postoperatively.

The femoral distal epiphysis of ovariectomized rats as a site for studies on osteoporosis: structural and mechanical evaluations

OBJECTIVE

To investigate in detail the mechanical and structural characteristics of cancellous bone from the femoral distal epiphysis of normal and ovariectomized rats, and to provide reference values in order to improve experimental research on osteoporosis by characterising an alternative and complementary anatomic site.

METHODS

40 female Sprague-Dawley rats (10 months old) were randomly divided into 4 groups of 10 each: baseline, ovariectomized (Ovx), sham-operated (Sham-Ovx) and sham-aged (Sham-Aged). Baseline animals were sacrificed at the beginning of the study. Ovx and Sham-Ovx animals were sacrificed 16 weeks after surgery, whereas Shamaged rats were killed when aged 14 months. Femurs were excised and densitometric, ultrasonographic, mechanical and histomorphometric analyses were performed.

RESULTS

When comparing the Ovx group with the others, ultrasonographic and densitometric measurements showed significant decreases (p < 0.0005) amounting to 3-5% in the amplitude dependent speed of sound (AD-SOS) and 13-20% in the BMD, respectively. Significant decreases were also seen in the femoral condyle Max. Load (28-31%; p < 0.0005) and Elastic Modulus (19-25%; p < 0.005) in the Ovx group in comparison with the Sham-Ovx and Sham-Aged groups. Histomorphometric analysis showed a significant cancellous bone loss (p < 0.0005). Densitometric (p < 0.01), histomorphometric (p < 0.01) and mechanical (p < 0.05) parameters were correlated with AD-SOS. Among the histomorphometric parameters, stepwise regression analysis showed that the trabecular bone volume (BV/TV) and Max. Load correctly predicted AD-SOS (p < 0.0005) and BMD (p < 0.0005).

CONCLUSION

The data from this study characterize osteopenia occurring in the rat distalfemur 16 weeks after ovariectomy and provide methodology and reference values forfurther investigations on osteoporosis and bone-implant osteointegration in osteopenic bone.

Capecitabine and oxaliplatin in advanced colorectal cancer: a dose-finding study

PURPOSE

Capecitabine and oxaliplatin are both active anticancer agents in the treatment of patients with advanced colorectal cancer (ACRC). The aim of this dose-finding trial was to determine the maximum-tolerated dose (MTD), the dose-limiting toxicities (DLTs) and the activity of the combination in patients with advanced colorectal cancer.

PATIENTS AND METHODS

Twenty-five chemotherapy-pretreated patients received the combination of capecitabine and oxaliplatin. Capecitabine was administered orally twice a day continuously for 14 days in doses ranging from 1,650 to 2,500 mg/m2/d, and oxaliplatin was administered as a two-hour infusion on day 1 using dose, ranges from 100 to 130 mg/m2 repeated every three weeks.

RESULTS

Twenty-five patients were assessable for toxicity, and DLTs were diarrhea (grade > or = 3: 27%) and stomatitis (grade > or = 3: 9%) at dose level VI. Dose level V (capecitabine 2500 mg/m2 and oxaliplatin 120 mg/m2) was found to be the MTD. Hematological toxicity was minimal, overall neurotoxicity (grade 1-4) was 27% with 1% grade 3-4. A global response rate was 17% (95% confidence interval (95% CI): 2%-32%) and the median overall survival was 12 months.

CONCLUSION

The recommended dose for further phase II studies is capecitabine 2,500 mg/m2/d with intermittent schedule and oxaliplatin 120 mg/m2 every three weeks. The toxicities were mainly gastrointestinal: diarrhea, stomatitis and vomiting. This combination should be studied in phase II trials in advanced colorectal.

Gaseous elemental mercury as an indoor air pollutant

Mercury is not commonly considered a household air pollutant; however, a number of potential sources of the metal exist in residential settings. Eleven of 12 indoor sites sampled in this study showed levels of airborne mercury that were significantly elevated over outdoor concentrations (range 6.5-523 ng m(-3)). In addition, this and other published research suggest that up to 10% of households may have levels of airborne mercury above the U.S. EPA reference concentration (300 ng m(-3)) due to historic accidents with mercury containing devices. Exposure to mercury via indoor air is seen as second only to fish consumption as a source of mercury in the general population. Large seasonal changes in indoor mercury levels were identified in this study suggesting that short-term monitoring of mercury-contaminated sites is not sufficient to adequately assess the potential health risks and effectiveness of remediation strategies.

Comparison of calcitonin, alendronate and fluorophosphate effects on ovariectomized rat bone

The effects of calcitonin, alendronate and fluorophosphate preventive treatment on ovariectomized rat femur were studied by comparing densitometric, mechanical, mineralogical and histomorphometric data. Sixty retired breeder female Sprague-Dawley rats, aged 10 months, were randomly divided into six groups. A group (baseline) was euthanized at the beginning of the study as a baseline group; four groups were ovariectomized and one was sham-operated (sham) and considered as a sham-aged group. A group of ovariectomized rats was used as a sham-therapy control (OVX) and received only deionized drinking water, while the other three received: a) salmon calcitonin (SCN) at a dose of 2 IU/kg/d s.c. (OVX + SCN); b) alendronate sodium salt (ALN) at a dose of 6 microg/kg/d administered by gavage (OVX + ALN); and c) L-glutamine monofluorophosphate (G-MFP) and calcium at a rate of 1:30 F/Ca at a dose of 0.21 mg F/6.30 mg Ca per kg/d by gavage (OVX + MFP). Significant increases (P < 0.05) of about 15 and 27% in femoral proximal epiphysis bone mineral density (BMD) of the OVX + ALN group were observed versus healthy groups and the OVX group, respectively. The OVX + ALN group also showed significant increases in femoral mid-diaphysis BMD when compared to OVX (18%, P < 0.001), OVX + SCN (14%, P < 0.05) and OVX + MFP (18%, P < 0.001) groups. In the OVX + MFP group, the three-point bending test demonstrated significant increases (P < 0.05) in maximal load of 21 and 22% when compared to the OVX and OVX + SCN groups, respectively. Also, stiffness data showed significant increases of the OVX + MFP (17%) and sham (14%) groups in comparison with the OVX group. A decrease in Mg (42%, P < 0.05), and increases in Ca (15%, P < 0.0001) and PO4 (8%, P < 0.005) content were found by comparing OVX + MFP and OVX groups. Trabecular bone volume results showed significant increases by comparing OVX + ALN and OVX groups (12.20%, P < 0.0005), as well as control groups. Tested agents were able to reduce the bone loss due to estrogen deficiency, but this did not always produce an increase in strength of the treated bone. Alendronate treatment prevented a decrease in bone mineral density and maintained bone mechanical properties after ovariectomy without impairment of bone mineralization in aged rats.

Effect of L-lysine and L-arginine on primary osteoblast cultures from normal and osteopenic rats

A therapeutic role of amino acids L-lysine (Lys) and L-arginine (Arg) in osteoporosis and fracture healing was demonstrated previously by in vivo studies. In the present study, primary cultures of osteoblasts were used to investigate the effect of amino acids on gene expression (alkaline phosphatase activity, ALP; osteocalcin, OC; type I collagen), nitric oxide production (NO) and proliferation (MTT) of cells. Cells were isolated from the distal femurs of normal and osteopenic rats. Normal and osteopenic bone-derived cells were divided into four groups: control, Lys (0.587 mg/mL/d), Arg (0.625 mg/mL/d), and Lys + Arg (0.587 + 0.625 mg/mL/d). No evidence of differences between normal and osteopenic bone-derived cultures in basal conditions was observed. A significant (P = 0.002) increase of 10.4% in NO production was observed in normal bone-derived osteoblasts treated with Lys + Arg when compared to the control group at 7 days. At the same time, normal bone-derived osteoblasts treated with Arg and Lys + Arg showed significant increases in type I collagen synthesis of 25.3% and 28.4%, respectively, when compared to the control group. Osteopenic bone-derived osteoblasts showed significant (P = 0.002) increases of 27.6% in MTT and 28.7% in cell count at 48 hours when treated with Lys + Arg in comparison with the control group. At 7 days, NO production and type I collagen synthesis increased significantly (P< 0.005) both in osteopenic bone-derived osteoblasts treated with Arg (NO: 18.5%; type I collagen: 34.4%) and Lys + Arg (NO: 23.7%; type I collagen: 20.9%) compared to the control group. Finally, a significant (P = 0.025) decrease of 5.8% in OC level was observed in osteopenic bone-derived osteoblasts treated with Arg. Results suggest that the potential therapeutic effect of Lys and Arg on bone could be related, at least in part, to an improvement of NO production and type I collagen synthesis by osteoblasts both in normal and in osteopenic bone. In osteopenic bone-derived osteoblasts this synthetic phase is preceded by an initial increase of cell proliferation.

Laser biostimulation of cartilage: in vitro evaluation

An in vitro study was performed to evaluate the laser biostimulation effect on cartilage using a new gallium-aluminium-arsenic diode laser. Chondrocyte cultures were derived from rabbit and human cartilage. These cells were exposed to laser treatment for 5 days, using the following parameters: 300 joules, 1 watt, 100 (treatment A) or 300 (treatment B) hertz, pulsating emission for 10 minutes, under a sterile laminar flow. Control cultures (no treatment) received the same treatment with the laser device off. Cell viability was measured by MTT assay at the end of the laser treatment and then after 5 days. Neither rabbit nor human cultured chondrocytes showed any damage under a light microscope and immunostaining control following laser treatment. The MTT test results indicated a positive biostimulation effect on cell proliferation with respect to the control group. The increase in viability of irradiated chondrocytes was maintained for five days following the end of the laser treatment. The results obtained with the Ga-Al-As diode laser using the above tested parameters for in vitro biostimulation of cartilage tissues provide a basis for a rational approach to the experimental and clinical use of this device.

The role of tumour markers in improving the accuracy of conventional chest X-ray and liver echography in the post-operative detection of thoracic and liver metastases from breast cancer

The aim of this retrospective study was to assess the value of a serum tumour marker panel in selecting from among the patients with equivocal chest X-ray (CXR) or liver echography (LE) those with thoracic or liver metastases respectively. Between January 1984 and December 1999, 467 (341 non-relapsed and 126 metastatic) breast cancer patients were followed-up postoperatively. Among the 126 metastatic patients 36 showed thoracic (19 patients) or liver (17 patients) metastases, alone or in conjunction with other organs as the first evidence of distant spread. We focused on this series of 377 patients including 341 non-relapsed plus 36 with liver or thoracic metastases. The patients were followed-up after mastectomy with serial determinations of a panel of CEA-TPA-CA15.3 tumour markers, bone scintigraphy, CXR and LE. Up to December 1999, equivocal CXR occurred in 23 (6.1%) patients of whom 11 (47.8%) developed thoracic metastases; 14 (3.7%) patients showed an equivocal LE of whom 5 developed liver metastases. In the 37 patients with equivocal CXR or equivocal LE prolonged clinical and imaging follow-up over 41 +/- 36 months (mean +/- SD, range 3-163) was used to ascertain the presence or absence of thoracic or liver metastases. In the 23 patients with equivocal CXR the negative and positive predictive values of the tumour marker panel to predict thoracic metastases were 92% and 100% respectively. In the 14 patients with equivocal LE the negative and positive predictive values of the tumour marker panel for prediction of liver metastases were 90% and 100% respectively. This study shows that in breast cancer patients the CEA-TPA-CA15.3 tumour marker panel has a high value for selecting those patients at high risk of developing clinically evident pulmonary or liver metastases from amongst those subjects with equivocal CXR or equivocal LE.

Biomaterials in spinal fixation. An experimental animal study to improve the performance

Different pedicle screws were biomechanically and morphologically studied and compared through the use of an animal model to determine their efficacy and resistance in spinal fixation. The principal objective was to compare biomechanical and histomorphological aspects of HA-coated screws to uncoated ones. Fourty-eight cylindrical transpedicular self-tapping screws divided into three groups of sixteen each were employed; Group A: stainless steel screws; Group B: titanium screws; Group C: HA-coated titanium screws. The screws were implanted bilaterally and randomly into the L3, L4, and L5 pedicles of eight adult mongrel sheep. The final insertion torque was measured in all the implants. After one and four months, upon euthanization, four samples per group were extracted from the surrounding bone and the screw extraction torque was measured. The remaining samples were examined and processed for histological and histomorphological evaluations. No differences were observed at one month among the extraction torque of the three groups. After four months the only significance between insertion and extraction values was for the HA group, i.e. p=0.001. Comparing the extraction torque values of the three groups after four months of healing, the HA-coated group showed a greater than twofold increase (p<0.0005). No differences were observed at one month among the percentages of bone-implant contact in the three groups. After four months the percentage was significant only for the C group (p<0.0005). At four months a correlation was found between the morphological and the biomechanical data of group C (p<0.0005). The use of hydroxyapatite-coated screws could act as an effective method to improve the bone-implant interface, thus obtaining a strong fixation of the implant independently of the arthrodesis achieved with bone graft.

The management of idiopathic thrombotic microangiopathy. Changing trends

Thrombotic microangiopathy, including the two related syndromes thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome, is a rare and severe multisystem disorder, due to widespread deposition of intravascular microthrombi consisting mainly of platelets, with subsequent consumption thrombocytopenia, microangiopathic hemolytic anemia, renal abnormalities, and neurologic disturbances. The epidemic, verotoxin-induced hemolytic-uremic syndrome, typically associated with prodromal diarrhea, mainly affects young children in small outbreaks. By contrast, idiopathic thrombotic microangiopathy generally affects adults in a sporadic form; it has a more devastating course and a less favourable outcome. Over 90% of the reported cases in the adult, when untreated, have progressed to death within three months of diagnosis. Since the introduction of plasma exchange, a dramatic change in the prognosis of the disease has taken place, although the mortality rate still remains considerable. Indeed, improved survival is the most striking feature of adult thrombotic microangiopathy compared to some decades ago. In the present article we will focus on the evolving concepts able to exert a considerable impact in the management of the adult idiopathic form of thrombotic microangiopathy.