Fibroblast growth factor-2 alters the effect of eroding polylactide-polyglycolide on osteogenesis in the bone chamber

The effects of recombinant human fibroblast growth factor-2 (rhFGF-2) in the presence of eroding 50:50 poly(DL-lactide-co-glycolide) (PDLLG) on acute bone healing were studied in the optical bone chamber (BCI). BCIs were loaded with disks of PDLLG surrounded by one of four rhFGF-2 doses. Fifty-two female rabbit right tibias were implanted. Commencing the third week post implantation (W3) healing in the BCI compartment was observed weekly, using intravital microscopy, until W8. The doses were: unloaded, loaded with polymer only, and polymer plus 0.5, 1.0, and 10 microg rhFGF-2. Videotaped and photographed bone images were measured and analyzed using a frame-grabber digitizing system. Comparison with controls revealed that ossification rates were significantly above normal in rabbits loaded with polymer plus any of the rhFGF-2 doses. Comparison with polymer-only BCIs showed that PDLLG plus any of the three rhFGF-2 doses was linked with ossification rates significantly higher than baseline. The results indicated that FGF-2 in the dose range studied effectively can overcome the retarding effects of eroding polymer on ossification that has been reported by this laboratory. Interpretation of the retarding effects of the polymer disks, although consistent with previously studied washer-shaped devices of the same material, was complicated by a difference in erosion rate. This result supports the notion that erodible device geometry is a major factor in determining biocompatibility and must be considered in the design of carriers. Accordingly, programming of dose specificity for delivering a given polypeptide cytokine to a given host site must allow for the inhibitory effects of an eroding carrier and the influence of device geometry on these effects and erosion.     

Loss of dopamine D2 receptors in Alzheimer''s disease with parkinsonism but not Parkinson''s or Alzheimer''s disease

Qualitative analyses of midfoot stabilization in triple arthrodeses utilizing bone staple versus 4.5-mm cannulated cancellous screw fixation, with and without washers, were performed in fresh cadaveric specimens. Twenty-two trials (11 matched-pair feet) were used for direct comparison. Stiffness, defined as force/displacement, was determined at each talonavicular and calcaneocuboid joint. Ultimate load failure points of each specimen were also calculated. Trial results showed no statistically significant difference in stiffness or ultimate failure between these two forms of midfoot fixation for triple arthrodeses.     

Treatment of tibial plateau fractures by limited internal fixation

Seventy-five adults who sustained 76 tibial plateau fractures were treated according to a prospective protocol using instability in extension as the principal indication for operative fixation. Patients showing instability underwent closed manipulative reduction under fluoroscopic guidance. If significant joint depression persisted after reduction, elevation of the fracture was performed either from below using bone punches through a cortical window or via limited arthrotomy. Iliac crest bone graft was used to buttress depressed fractures. Fixation was then secured using 7-mm cannulated screws with washers or buttress plates and screws. Postoperatively, 58 of 76 knees were managed in a hinged knee brace, allowing the patient early range of motion and protected weightbearing for 8 weeks. Patients who were found to have a stable knee were treated with Bledsoe braces according to the postoperative protocol. In the 75 patients, 18 of the 76 knees were unsuitable for percutaneous screw fixation because of fracture complexity requiring plates, severe open injuries, or inadequate reductions with limited fixation had been done. A minimum followup of 12 months was obtained in 55 patients (range, 12-59 months). All fractures had healed at the time of followup. Eighty-seven percent of the patients at followup had a successful outcome using Rasmussen's criteria. Fourteen of these patients had arthroscopic assisted reduction or evaluation. All seven patients who had poor outcomes had AO Type C3 fracture patterns. Severely depressed or comminuted fractures or fractures with significant metaphyseal diaphyseal extension may not be suitable for this technique and require the addition of an external fixation device or buttress plate to maintain the reduction and allow for early range of motion.     

The effect of screw insertion torque on tendons fixed with spiked washers

The long-term success of a hamstring tendon graft depends not only on the type of device that is used for fixation but also on the mechanical interlocking of the soft tissue between the fixation device and bone. The purpose of this study was to evaluate the effect of screw insertion torque on the structural properties of soft tissue fixed to bone with a spiked metal washer. Two bovine tendons, one similar in size to a human semitendinosus tendon and the other similar in size to a human gracilis tendon, were secured to a bovine femur using a figure-of-8 technique with screws and metal spiked washers. A single load to failure was applied at 25 mm/sec. A significant positive linear correlation was observed between fixation screw insertion torque magnitude and the ultimate failure load value. An increase in the fixation screw insertion torque produced an increase in the ultimate failure load value. Similarly, there was a significant positive linear correlation between fixation screw insertion torque magnitude and the average maximum linear load value. No relationship was detected between screw insertion torque magnitude and the linear stiffness values of the tendon-fixation construct, indicating that a reproducible model was used. This study demonstrates that screw insertion torque is an important variable that controls the initial strength of soft tissue fixation to bone.     

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. III. The significane of pigment for the result of the cyclopentolate provocative test in suspected or untreated open-angle glaucoma

Significant elevations of IOP, i. e. responses, occurred in eyes with suspected or untreated open-angle glaucoma during the mydriasis test with 1% cyclopentolate (CPT). The possible role of pigment in the IOP elevations seen in the responders was studied. Pigment was liberated in the aqueous, sometimes very profusely, in 88 (31.9%) of 276 eyes during CPT. The maximal IOP elevations, ad 20 mmHg, were seen in just these eyes. They were eyes with capsular or pigmentary glaucoma or eyes in which exceptionally heavy pigment was demonstrated in the chamber angle for other reasons. There was a statistically significant correlation between pigment liberation and IOP elevation during CPT. Evidently profuse pigment liberation may have caused transient blocking of the trabecular meshwork, obstruction of aqueous outflow and elevation of IOP. Liberation of pigment in the aqueous during CPT was statistically highly significantly more profuse in eyes with pseudoexfoliation than in eyes without pseudoexfoliation. An equally significant correlation with demonstrated between the grade of chamber angle pigmentation and the degree of pigment liberation during CPT. The significance of pigment for IOP elevation was seen also in the statistically highly significantly more profuse pigmentation of the chamber angle in the responder than in the non-responder eyes.     

A spectrophotometric assay for allicin and alliinase (Alliin lyase) activity: reaction of 2-nitro-5-thiobenzoate with thiosulfinates

Physiological parameters such as pH and oxygen tension probably play significant roles in the regulation of haemopoiesis in the bone marrow microenvironment, but these roles have yet to be characterized in detail. We have found that changes in culture pH (0.2 units) can cause significant changes in the culture composition of mature cells and colony-forming cells (CFCs), especially in the presence of erythropoietin (Epo). Peripheral blood (PB) CD34+ cells cultured at different pH values (7.15-7.6) were characterized using total cell counts, colony assays, morphological analysis. haemoglobin staining, flow cytometry, immunocytochemical staining, and Western blots. Cultures performed at high (7.6) pH contained greater numbers of haemoglobin-positive and band-3-positive cells. and acquired these erythroid differentiation markers sooner than standard (7.35) and low (7.1) pH cultures. Flow cytometry using CD71 and CD45RA antigens also indicated that erythroid differentiation proceeds faster at high pH and is blocked at an intermediate stage by low pH. Morphological data confirmed that high pH cultures had been shifted towards late-stage erythroid compartments as compared to low and standard pH cultures. These findings have important implications both in elucidating the regulatory role of pH in the bone marrow microenvironment and for the design of in vitro systems to study the development of erythroid cells.     

Impaction of cancellous bone grafts impairs osteoconduction in titanium chambers

The method of using morselized compacted cancellous allografts for hip arthroplasty revision shows results that seem to differ dramatically from other kinds of allografting. In structural cancellous allografts, bone ingrowth usually is limited to 2 to 3 mm, whereas morselized compacted grafts seem to be remodeled totally in several cases, as judged by radiography. In the current study, impacted cancellous allografts were compared with unimpacted allografts. Seventeen rats had a bone conduction chamber implanted in the tibias bilaterally. On one side the chambers contained an impacted graft (bone volume fraction 65%) and on the contralateral side an unimpacted graft (bone volume fraction 35%). Impaction of the grafts was done preoperatively with a pressure of either 25 or 2500 MPa. Ingrowing bone could enter the cylindrical interior of the chamber only at one end. After 6 weeks the mean distance the ingrown bone had reached into the graft was measured on histologic slides. With both impaction pressures, the bone ingrowth distance was decreased to 30% of the unimpacted controls. It appears that impaction alone does not have a favorable effect on the osteoconductive properties of a bone graft. On the contrary, impaction seems to disfavor osteoconduction. However, in the clinical situation this is not necessarily a disadvantage.     

The effects of guided bone regeneration and grafting on implants placed into immediate extraction sockets. An experimental study in dogs

Guided bone regeneration (gbr) for the treatment of insufficient bone volume around implants can be performed using membranes with or without grafting materials (i.e., autogenous, allogenous, xenogenous, or alloplastic grafts). A possible way to evaluate the quality of implant osseointegration is the torque necessary to remove implants from their bony housing. The aim of this study was to compare the torques necessary to remove dental implants from implant beds reconstructed with different bone substitutes and GBR or GBR alone in 6 adult mongrel dogs. All mandibular premolars were extracted and 3 extraction sockets on each side were enlarged using a trephine bur. A 13 mm titanium screw-type dental implant (3.75 mm diameter) was placed in each enlarged extraction socket so that only the apical 3 to 4 mm were engaged in bone. The 3 defects were then randomly treated with either 1) canine demineralized freeze-dried bone allograft (DFDBA) plus GBR using an expanded polytetrafluoroethylene membrane (DFDBA+GTAM); 2) bioabsorbable hydroxyapatite and GBR (HA+GTAM); or 3) GBR (GTAM alone). After 6 months, the torque to remove the implants was measured in 4 animals and analyzed using ANOVA. There were no statistically significant differences between the 3 groups (GTAM alone: 46.37+/-16.41 Ncm; HA+GTAM: 46.00+/-16.59 Ncm; DFDBA+ GTAM: 52.15+/-29.24 Ncm). In addition, the influence of early removal of barriers on the torque values was evaluated with the t-test. Comparing exposed versus retained membranes by treatment modality, the only statistically significant difference was found in the DFDBA+GTAM group. When the torque values of all implants with exposed and retrieved membranes were compared to all those with retained membranes a significant difference could be detected. Histologic sections were prepared from the 2 dogs not included in the removal torque testing. In the histometric analysis the GTAM alone group showed a mean mineralized bone-to-implant-contact of 27.1%, the DFDBA+GTAM group of 34.6%, and the HA+GTAM of 39.3%. The mineralized bone-to-implant-contact of the HA+GTAM group was significantly higher than that of the GTAM alone group. In addition, the mineralized bone-to-implant-contact was divided into an apical and coronal part using the apical seventh thread as the dividing landmark. In the apical region, there was no significant difference between the groups regarding mineralized bone-to-implant-contact. In the coronal part the mineralized bone-to-implant-contact of the GTAM alone group was significantly lower compared to the other 2 groups. Within the limits of this investigation, it can be concluded that the type of grafting material will not influence torque removal values, but that early membrane exposure and removal will negatively influence the torque measurements. The combination of GBR with a bone substitute increased the mineralized bone-to-implant contact.     

The tabletting machine as an analytical instrument: qualification of the measurement devices for punch forces and validation of the calibration procedures

The quality of force measurement in an eccentric tabletting machine equipped with piezo-electric load washers mounted under pre-stress at the upper and lower punches, and the reliability of their calibration in situ and under working conditions were carefully investigated, since this tabletting machine is used as an 'analytical instrument' for the evaluation of the compression behaviour of pharmaceutical materials. For a quasistatic calibration procedure the repeatability under standard conditions and the robustness against variations in machine settings, installation conditions, equipment and handling were evaluated. Two differently constructed reference load cells equipped with strain gauges were used for the calibration of the upper punch sensor. The lower punch sensor was calibrated against the upper one. Except for a mechanical hysteresis, owing to uneven stress distribution over the piezo-electric sensors, the results of the quasistatic measurements are assessed to be satisfactory. In addition, dynamic calibrations were performed. One of the strain-gauged load cells was used in addition to two piezo-electric load washers installed without pre-stress. The dynamic behaviour of all the transducers used is deficient. While for the piezo-electric sensors a significant change in the slope of the calibration function with respect to the quasistatic behaviour was observed, for the strain-gauged load cell a pronounced hysteresis must be noted. Comparing the dynamic behaviour at different profiles of rates of force development generated by variations in machine speed and by maximum force setting, the variability in the sensitivity of the upper and lower punch piezo-electric load washers is comparatively small.     

The clinical, angiographic and procedural predictors of thrombosis and restenosis in Micro stent II (AVE) coronary stents]

In the present study, the potential of a diphenylphosphorylazide-crosslinked type I bovine collagen membrane was evaluated in the healing of mandibular bone defects applying the biological concept of guided bone regeneration. The experiment was carried out on 25 Wistar rats. After exposing the mandibular ramus bilaterally, 5 mm diameter full-thickness circular bone defects were surgically created. While the defect on one side was covered by the membrane (experimental), the defect on the other side was left uncovered (control) before closure of the overlying soft tissues. The rats were sacrificed in groups of 5 after 7, 15, 30, 90, and 180 days of healing. Although at early stages of healing similar amounts of bone formation were observed in the experimental and control defects, after 1 month of healing, most of the experimental defects were completely closed with new bone, while in the control defects, only limited amounts of new bone were observed at the rims and in the lingual aspect of the lesions. In the 90- and 180-day animals, all experimental defects were completely closed, while in the control defects, no statistically significant increase in bone regeneration was observed. The increase in percentage of bone regeneration in the experimental defects was statistically significant between the 15-day specimens as compared with the 7-day specimens (P < 0.01) and likewise between 30-day and 15-day specimens (P < 0.001). It can be concluded that a DPPA-crosslinked collagen membrane yields biocompatibility, ad hoc mechanical hindrance, and handling characteristics suitable for guided bone regeneration applications in this experimental model.     

The reproducibility of ultrasound bone measures in a triethnic population of pregnant adolescents and adult women

We used bone ultrasound technology with its measurement of attenuation (broadband ultrasound attenuation [BUA] as dB/MHz) and sound velocity (speed of sound as m/s) for assessing the quantitative ultrasound index (QUI) summary measure in a triethnic population of 280 pregnant women. The study purpose was to describe the reproducibility of the ultrasound technology and determine if the correlations of age, weight, and ethnicity with the bone status measures in this population are consistent with the correlations of age, weight, and ethnicity that have been reported with other technologies that measure bone mass. We evaluated the first 280 women enrolled in our longitudinal study of lead turnover from maternal bone during pregnancy and lactation. Enrollees were pregnant, aged 12-29 years, and self-classified as black, white, or Hispanic. Bone ultrasound was measured twice at entry to prenatal care, which, on average, was at 14 weeks gestation. Reproducibility was described with intraclass correlations and the standard error of measurement. Age, weight, and ethnicity were associated with bone status measures using Spearman correlations and generalized linear models. The reproducibility of the summary bone measure, QUI, was high (96-97%). Variation in age and ethnicity did not alter reproducibility; however, the reproducibility of the attenuation measure (BUA as dB/MHz) lessened with increasing weight, declining from 95% to 89%. Since this attenuation is included in the summary QUI measure, there was a slight, and nonsignificant, decline in QUI reproducibility (from 97% to 96%) as women increased in size. There were no statistically significant differences in mean bone ultrasound measures according to age, where ages ranged from 12-29 years. Women who categorized themselves as black had, on average, an 8.5% greater QUI than did women who classified themselves as Hispanic or white. There were no significant pair-wise differences in mean ultrasound measures of bone between women classifying themselves as Hispanic or white. The use of ultrasound is a highly reproducible measure to assess bone characteristics in a population of pregnant adolescent and young adult women and its summary measure of bone mass is correlated with ethnic as well as body size characteristics.     

Spontaneous erythroid colony formation as the clue to an underlying myeloproliferative disorder in patients with Budd-Chiari syndrome or portal vein thrombosis

Results from this laboratory have shown that bone metabolism is directly related to extracellular pH and that high concentrations of tobramycin released from impregnated polymethylmethacryrate (PMMA) beads has pH-dependent toxic effects on bone. In the present study, beneficial effects of calcium hydroxide-impregnated PMMA were investigated regarding tobramycin toxicity and bone metabolism in chick embryo tibiae in vitro. Also using Ca(OH)2 as a pH regulator, the antibiotic efficacy of tobramycin-impregnated PMMA was evaluated with respect to inhibition of Staphylococcus aureus growth. When Ca(OH)2 was added to PMMA beads containing tobramycin, the beads released hydroxyl and calcium ions into the culture medium and released more antibiotic than beads containing only tobramycin. Bone metabolism (glycolysis, total protein synthesis, and collagen synthesis) was enhanced by Ca(OH)2-impregnated beads with or without tobramycin. Additionally, bacterial growth was inhibited more strongly when S. aureus was incubated with tobramycin- and Ca(OH)2-impregnated PMMA disks than with disks containing only tobramycin. This study demonstrates the feasibility of adding Ca(OH)2 to tobramycin-impregnated PMMA beads as a regulator of local pH and a promoter of bone metabolism for protection of bone when high concentrations of tobramycin are used to treat osteomyelitis. It also suggests that lower concentrations of antibiotic may be effective if Ca(OH)2 and tobramycin are administered simultaneously.     

Anterior chamber contamination during cataract surgery with intraocular lens implantation

PURPOSE: To measure anterior chamber bacterial and fungal contamination at the beginning and end of cataract surgery with intraocular lens (IOL) implantation in a large series of patients and to determine the influence of preoperative treatment and operative technique on contamination. SETTING: Department of Ophthalmology, County Hospital of Salzburg, Austria. METHODS: This prospective study comprised 700 consecutive patients having planned cataract extraction (511 phacoemulsification, 189 extracapsular cataract extraction [ECCE]). Thirty-four patients required an anterior vitrectomy; 8 myopic patients did not receive an IOL. A preoperative smear and two intraoperative (at the beginning and end of surgery) anterior chamber aspirates were obtained from each patient. Postoperative smears were obtained at discharge. Three preoperative treatments were evaluated: no lacrimal system irrigation, no topical antibiotic (n = 282); lacrimal system irrigation with balanced saline solution, no topical antibiotic (n = 243); lacrimal system irrigation, antibiotic (neomycin) eyedrops (n = 175). All patients received topical indomethacin twice a day preoperatively. RESULTS: Preoperative conjunctival smears showed bacterial growth in 76.6% of eyes, with coagulase-negative staphylococci (75%) the most common bacteria. Anterior chamber aspirates were culture positive in 14.1% at the beginning and in 13.7% at the end of surgery, with coagulase-negative staphylococci and corynebacteria the most common. Contamination rates of conjunctival smears taken at discharge were significantly lower (35%) than those taken preoperatively. There was no statistically significantly higher risk of anterior chamber contamination in eyes having ECCE than in those having phacoemulsification. Preoperative treatment did not statistically significantly influence intraoperative aqueous humor contamination rates. There were no cases of acute postoperative endophthalmitis. CONCLUSION: Bacteria entered the anterior chamber during cataract extraction and remained there at the end of surgery in a significant percentage of patients. Surgical technique, preoperative antibiotics, and preoperative lacrimal system irrigation had no statistically significant effect on contamination.     

Immunoreactive parathyroid hormone, 25-hydroxycalciferol and bone histology in renal osteodystrophy (author's transl)

Immunoreactive parathyroid hormone (iPTH) and 25-hydroxycalciferol (25(OH)D) serum levels were determined in 32 patients with renal osteopathy, they were correlated with the results of bone biopsy and other clinical parameters. iPTH was closely related to bone histology, it did not correspond to serum calcium and alkaline phosphatase, but the correlation to serum phosphate was statistically significant. 25(OH)D levels were not related to the histological findings of osteomalacia or increased bone resorption, while a correlation between the vitamin D metabolite and serum calcium could be observed. Since iPTH and 25(OH)D levels exhibited a significant correlation, an inhibitory effect of 25(OH)D on parathyroid gland function in renal failure was discussed.     

Modifications in the rhythm of schizogony in Plasmodium chabaudi chabaudi associated with the selection of chloroquine resistance

Thirty-two patients affected with skeletal conditions were examined with MRI using Short TI Inversion Recovery sequence and Spectral Presaturation with Inversion Recovery (SPIR) sequence as well as Spin-Echo (SE) T1-weighted sequence and Fast Spin-Echo (FSE) T2-weighted sequence to compare their value in the assessment of skeletal lesions. SPIR sequence was performed after intravenous injection of Gd-DTPA. The lesions included primary bone tumors (10 cases: 1 osteosarcoma, 1 periosteal sarcoma, 1 Ewing's sarcoma, 1 chondrosarcoma, 2 non-ossifying fibromas, 1 chondroma, 1 chondromyxoid fibroma, 1 desmoplastic fibroma and 1 bone cyst), metastases (7 cases: 3 prostate, 3 breast, 1 lung-squamous cell carcinoma), infections (12 cases: 9 osteomyelitis, 3 spondylodiscitis), sacroiliitis (1 case) and posttraumatic bone bruise (2 cases of bone marrow edema). The four sequences were compared by using both qualitative and quantitative evaluation. Qualitative evaluation showed that STIR sequence was better than SPIR sequence (performed with Gd-DTPA) for lesion conspicuity (p < .016) and for signal intensity uniformity (p < .03). Compared with SE T1 and FSE T2 sequences, fat-suppressed sequences were superior for conspicuity, margins, and extension of the lesions (range of p < .001-.017). Only SPIR with Gd-DTPA sequence, compared with SE T1 sequence for lesion conspicuity was not statistically significantly different. Quantitative evaluation showed statistically significant higher values of percent contrast (%C) and contrast-to-noise ratio (C/N) for STIR sequence compared with SPIR sequence (%C p < .004; C/N p < .040). This study suggests that STIR sequence and SE T1-weighted sequence provide high sensitivity in lesion detection and good anatomical definition. The use of a fat-suppressed sequence with Gd-DTPA can be useful for lesion characterization.     

Basic fibroblast growth factor promotes bone ingrowth in porous hydroxyapatite

The effect of basic fibroblast growth factor on tissue ingrowth and differentiation in porous hydroxyapatite of coralline origin was studied in a bone chamber model. The hydroxyapatite with or without basic fibroblast growth factor was placed in 22 mm3 titanium bone conduction chambers implanted bilaterally in rat tibiae. Ingrowing bone could enter the cylindrical interior of the chamber only at 1 end. It then penetrated the porous hydroxyapatite inside the chamber. The distance that the ingrown tissue had reached into the material then was measured on histologic slides. Because fibrous tissue always reached further into the material than did bone, both total tissue ingrowth and bone ingrowth distances were measured. In implants supplemented with 0.04 microg basic fibroblast growth factor in a hyaluronate gel carrier, the bone ingrowth distance was increased by 70% at 6 weeks, as compared with paired controls in the contralateral leg. The total tissue ingrowth distance also was increased by 58%. When the dose of basic fibroblast growth factor was increased to 1.0 microg, still using the hyaluronate carrier, there was no difference in bone ingrowth compared with controls, but this dose still increased the total tissue ingrowth. In hydroxyapatite with 1.5 microg basic fibroblast growth factor without hyaluronate gel at 4 weeks, no increase in bone ingrowth was shown, but total tissue ingrowth was increased. At 6 weeks, bone ingrowth and total tissue ingrowth were increased by 41% and 33%, respectively. With a lower dose of 0.15 microg without carrier, only the total ingrowth distance was increased. The results suggest that basic fibroblast growth factor may promote tissue ingrowth into porous hydroxyapatite and that bone ingrowth may be increased by appropriate doses. The hyaluronate gel carrier reduced the optimal dose.     

宫颈癌术后骨髓保护调强放疗研究

Objective: The aim of this study was to compare bone marrow-sparing intensity-modulated radiotherapy (IMRT)with IMRT without entering pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods: For a cohort of 10 patients, bone marrow-sparing IMRT and routine IMRT planning were designed. Theproscribed dose was 45 Gy/1.8 Gy/25f, 95% of the planning target volume received this dose. Doses were computed with a commercially available treatment planning system (TPS) using convolution/superimposition (CS) algorithm. Plans were compared according to dose-volume histogram (DVH) analysis in terms of planning target volume (PTV) homogeneity and conformity indices (HI and CI) as well as organs at risk (OARs) dose and volume parameters. Results: Bone marrow-sparing IMRT had an vantages over routine IMRT in terms of CI, but inferior to the latter for HI. Compared with routine IMRT, V5,V10, V20, V30, V40 of pelvic bone marrow of bone marrow-sparing IMRT reduced by 1.81%, 8.61%, 31.81%, 29.50%, 28.29%,respectively. No statistically significant differences were observed between bone marrow-sparing IMRT and routine IMRT in terms of small bowel, bladder and rectum. Conclusion: For patients with cervical cancer after hysterectomy, bone marrowsparing IMRT reduced the pelvic bone marrow volume irradiated at all dose levels and might be conducive to preventing the occurrence of acute bone marrow toxicity.     

Biomechanical study of sternal closure using rigid fixation techniques in human cadavers

BACKGROUND: We believe rigid plate fixation may be superior to wire fixation in sternal closure, as rigid fixation used in the craniofacial skeleton has shown greater stability, lower postoperative pain, and accelerated bone healing. We hypothesize that sterna fixed with titanium plates are more stable mechanically than sterna fixed with wires. METHODS: The sterna from human cadavers were used in this two-phased study. Phase I compared wires to four-hole titanium straight plates. Phase II compared wires to four-hole titanium custom H plates. The sterna were tested biomechanically using all fixation methods. RESULTS: Phase I showed no statistically significant difference in the stiffness or lateral displacement between the wired and straight plated sterna. Phase II showed a statistically significant greater stiffness (p < 0.05) and less lateral displacement (p < 0.05) in the custom plated sterna over the wired sterna. CONCLUSIONS: Our results showed that custom titanium H plates were superior to wire fixation. Furthermore, our results established the importance of plate configuration in sternal fixation. Our study may have beneficial clinical implications, as decreased motion at the sternotomy site could mean less postoperative pain, a decreased incidence of infection, and accelerated bone healing.     

Prediction of bone loss in patients with primary hyperparathyroidism using quantitative bone SPECT

Bone loss is a major complication of primary hyperparathyroidism (PHPT), and it has significant implications in the treatment of this disease. Bone turnover was measured in patients with PHPT, using quantitative bone SPECT (QBS), to determine if the rate of bone loss could be predicted before a significant decrease in bone mass occurs. METHODS: Forty-six patients were included in the study. QBS and bone mineral density (BMD) of the lumbar spine (LS) and femoral neck (FN) were done at baseline. The percent deviation of QBS in patients with PHPT from the values in normal matched controls was calculated. BMD was measured again after a mean of 17.5 mo in 38 patients, and in 29 patients a repeat BMD study was done after a mean of 41.4 mo. The change in BMD in patients with high and normal QBS values was compared using the nonparametric Mann-Whitney test. Regression analysis tested the correlation between baseline QBS values and BMD changes over time. RESULTS: For the FN, there was a statistically significant difference in the BMD change between patients with high and normal QBS values for short-term follow-up (-2.82%+/-4.80% versus 1.45%+/-4.67%, p < 0.05) and for long-term follow-up (-3.53%+/-5.34% versus 0.92%+/-2.40, p < 0.02). There was a negative correlation in the FN, r=-0.48 between QBS values and the percentage of change in BMD. There was no significant difference between the percentage of change in BMD in the LS in patients with high and normal QBS values for either short- or long-term follow-up. CONCLUSION: The results of this study show that QBS can predict bone loss in the FN in patients with PHPT. QBS can thus indicate the need for surgery at an early stage of the disease to prevent bone loss.     

A retrospective cost-effectiveness analysis of interferon as adjuvant therapy in high-risk resected cutaneous melanoma

PURPOSE: To determine the relative corneal endothelial toxicities of the following topical anesthetic agents: bupivacaine HCl 0.75%, unpreserved lidocaine HCl 4%, proparacaine HCl 0.5%, and tetracaine HCl 0.5%. METHODS: The experiment was conducted using pigmented rabbits. Approximately nine animals each were randomly assigned to eight groups. Right eyes received injections of 0.2 ml of one of the four anesthetic agents at one of two concentrations and left eyes received injections of 0.2 ml of balanced salt solution. Corneal thickness and clarity were measured before surgery and on postoperative days 1, 3, and 7. RESULTS: A statistically significant increase (P < 0.05) in corneal thickness and opacification over preoperative measurements was noted with injections of bupivacaine, lidocaine, and proparacaine, controlling for changes occurring in control eyes from surgery alone. Proparacaine was statistically more toxic than were the others. The toxicity of tetracaine was statistically indistinguishable from balanced salt solution, although mild toxicity was evident clinically. Injection of 1:10 dilutions of the same anesthetic agents failed to produce a statistically significant increase in corneal thickness or opacification on any postoperative examination. CONCLUSIONS: Anterior chamber injection of bupivacaine HCl 0.75%, unpreserved lidocaine HCl 4%, and proparacaine HCl 0.5% produces corneal thickening and opacification that is clinically and statistically significant. Tetracaine HCl 0.5% injection produces corneal thickening and opacification that is clinically apparent in some eyes but statistically insignificant. Ophthalmic surgeons should be aware of the potential for endothelial cell injury if anesthetic agents enter or are injected into the eye during cataract surgery in the concentrations supplied commercially.