Bone resorption and formation on the periosteal envelope of the ilium: a histomorphometric study in healthy women.

Continuation of net periosteal bone gain after cessation of longitudinal growth has been inferred from sequential radiographic morphometry. Accordingly, we performed histomorphometry of the periosteal surfaces of transilial bone biopsies from 57 healthy women aged 24-74 years, 29 premenopausal and 28 postmenopausal. Compared to the endocortical surface, the extents of eroded and osteoid surfaces were very similar, but the extents of osteoclast- and osteoblast-covered surfaces were 80-90% smaller, and both wall thickness and osteoid thickness were about 30% lower. Double tetracycline labels were present in only 11 cases. The second (demethylchlortetracycline) label was almost four times as long as the first (oxytetracycline) label, a much greater difference than on the endocortical surface, so that the extent of mineralizing surface was based only on the second label. Even so, adjusted apposition rates and bone formation rates were only about 20% of the endocortical values, and unlike the endocortical surface, formation rates were not higher in the postmenopausal than in the premenopausal women. Resorption, reversal, and formation periods were each much longer than on the endocortical surface. There was no correlation between periosteal and endocortical values for any variable. At least 54% of total cement line length was scalloped, implying reversal of remodeling direction from resorption to formation, and at least 18% of total cement line length was smooth, implying temporary arrest of bone formation. Convincing evidence of modeling, related to growth or mechanical stimulation, was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

A classification of in vivo bone labels after double labeling in canine bones

Labeling patterns were classified after double bone labeling of four male beagles, 10 months of age. Calcein and oxytetracycline were given on the 18th and the 7th day prior to simultaneous iliac and 11th rib biopsies. Undecalcified sections stained with the Villanueva bone stain were studied by epifluorescence microscopy. Five structures were identified and classified: the first or green label, the interlabel layer of mineralized bone, the second or yellow label, the post double-labeled mineralized bone layer, and osteoid seams. Doubly plus singly labeled surface equalled 40.8 +/- 8.4% of the total trabecular surface of the ilium. Doubly labeled surface as a percent of the total labeled surfaces equaled 55.5% in trabeculae and 68.1% in osteons, whereas green first-singly labeled surface equaled 24.2% and 11.9%, respectively, and yellow second-singly labeled surface equaled 20.3% and 20.0%, respectively. Unequivocal examples appeared in both biopsy sites of all four dogs of bone-forming systems that lacked one or the other label, or both, and also of systems in which cessation of mineralization or of new matrix formation occurred between the two labels and between the second label and the day of biopsy. The findings prove that the On-Off states in active bone-forming sites that have been postulated by other investigators do exist. Since widely different labeling patterns appeared in different bone-forming centers in the same bone and the same animal, a local factor rather than a systemic one should control those differences at the level of the BMU.     

The label escape error: Determination of the active bone-forming surface in histologic sections of bone measured by tetracycline double labels

Twenty healthy female beagles, all postbreeding age, were given two bone-labeling agents. Transilial bone biopsies were obtained and embedded undecalcified. Double-labeled, single-labeled, and unlabeled surfaces were determined along with the interlabel width on unstained sections under fluorescent light. Mean osteon thickness was determined on toluidine bluestained sections. A mathematical model for predicting the amount of singly labeled surface was tested and compared to the amount of surface actually found occupied by single labels of either color. We found that the model accurately predicted the amount of singly labeled surface and that the amount of singly labeled surface labeled by one agent was equal to that labeled by the other (r = 0.977, P < .001). We conclude that singly labeled surfaces in these animals were so labeled because bone formation either began or ended in the interval between administration of the two labels and that the proposed model accurately predicts this quantity of singly labeled surface without the need to measure any singly labeled surface. This label escape phenomenon must be taken into account when measuring bone formation rates by tetracycline labeling, and the model should be used whenever it is suspected that single labels appear that are not due to label escape.     

Indentation Properties of Young and Old Osteons

The purpose of this study was to quantify differences in indentation modulus and microhardness between labeled osteons identified by epifluorescent microscopy and neighboring unlabeled osteons. In microradiographs and backscattered images, newly formed osteons appear more radiolucent (darker) than older osteons. This is ascribed to incomplete mineralization of the osteon. However, the mechanical properties of these young osteons are unknown. Nine femoral cross-sectional specimens were obtained from five skeletally mature dogs. Prior to death, the dogs received a pair of calcein bone labels. Labeled osteons were identified under an epiflourescent microscope. Bone specimens were transferred to a nanoindenter specimen holder, and the previous identified labeled osteons were located. Labeled (n = 102) and unlabeled (n = 101) osteons were examined by instrumented indentation testing. Indents were made to a depth of 500 nm at a loading rate of 10 nm/second. There were significant differences in the indentation modulus (P < 0.001) of labeled (10.02 ± 3.61 gigapascal (GPa), mean ± standard deviation) and unlabeled (15.11 ± 3.72 GPa) osteons. Similar differences existed in microhardness measurements. Newly formed osteons had lower modulus (34%) and hardness (41%) than older osteons found in femoral cross sections. These data provide information on the indentation moduli of osteons during an early phase of mineralization compared to osteons that have completed mineralization.     

双膦酸盐的长期治疗增加了骨单位的矿化程度

目的评估双膦酸盐的长期应用对骨单位的次级矿化程度的影响。方法30只1岁龄猎犬按体重随机分成三组(每组雌雄各5只):对照组犬每天口服乳糖,低剂量组和高剂量组犬分别每天口服因卡膦酸钠incadronate0.3mgkg和0.6mgkg。所有犬持续给药3a。处死前进行四环素双标,处死后取左侧第9肋骨进行组织形态计测和次级矿化程度评估。结果组织形态计测表明两个双膦酸盐治疗组的骨激活频率(Ac.f)都明显低于对照组,分别降低了40%和82%。矿化程度的测定表明,低剂量和高剂量双膦酸盐组骨单位内的平均矿化程度(MDMB)都明显高于对照组,分别增加了22%和30%。双膦酸盐组MDMB分布曲线与对照组保持了相同的峰值,并且随治疗剂量的增大逐渐向高矿化端漂移。结论双膦酸盐长期应用明显抑制了骨转换,增加了骨单位的矿化程度。     

Sequential labelling of microdamage in bone using chelating agents.

Basic fuchsin labels microcracks, but a series of stains is required to differentiate between preexisting and test-induced microcracks and to label their growth in vitro. Basic fuchsin and five chelating agents-alizarin complexone, calcein, calcein blue, oxytetracycline, and xylenol orange-were randomly assigned to label microcracks in sequential rib sections from 10 donors. The density, length, and location of the microcracks did not differ significantly between the six stains, suggesting that each was equally effective in detecting microcracks. Paired specimens of trabecular bone were machined from bovine tibiae, stained with oxytetracycline, and fatigued in compression. One specimen from each pair was then stained with xylenol orange. Preexisting microdamage was stained with oxytetracycline, propagating microcracks with both stains and new, test-initiated damage with xylenol orange. Chelating agents are site-specific markers of the initiation and growth of microcracks.     

Tetracycline labeling of bone in vivo

Summary We have analyzed various aspects of tetracycline labeling technique for the measurement of bone apposition rate in vivo. Our efforts were restricted to those aspects that are frequently questioned when data obtained using this technique are interpreted as representing the rate of bone apposition. Rat bone was labeled in vivo by sequential injections of oxytetracycline at a dose range of 3 to 24 mg/kg body weight and at intervals ranging from 24 to 72 h. The bone apposition rate was calculated by measuring the distance from the first dose of label to the subsequent ones. As these distances are by far too small to be determined accurately by any available micrometer eyepiece, we have used a scanning microscope photometer which allows measurements on slow-forming sites that otherwise would have been considered nongrowing sites. Using these techniques, we have demonstrated that oxytetracycline has no effect on the bone apposition rate when used in the concentrations indicated. In addition, we found that at labeling intervals of 96 h or more, periods of osteoblastic inactivity are likely to be included in measurements at individual sites. The instantaneous apposition rate is thus underestimated at these long time intervals.     

胶原复合羟基磷灰石在修复下颌骨缺损中的骨动力学变化

目的 观察胶原复合羟基磷灰石（ＣＨＡ）替代自体骨修复下颌骨缺损。方法 在中国实验用小型猪的下颌骨制备直径２ｃｍ的全层骨缺损,实验组植入ＣＨＡ,对照组植入自体骨,用骨计量学方法,进行骨动力学测定。结果 实验组及对照组四环素双标记带之间的平均距离（ＤＤＬ）、矿化沉积速率（ＭＡＲ）差异显著（Ｐ〈０．０５）,而平均类骨质宽度（ＭＯＳＷ）及矿化延迟时间（ＭＬＴ）无显著差异（Ｐ〉０．０５）。表明ＣＨＡ有良好的     

Rib cage asymmetry in idiopathic scoliosis

Seventy-one patients attending a scoliosis clinic and 10 control subjects were studied by a stereoradiographic three-dimensional reconstruction of the spine and rib cage. The symmetry of each rib pair (at each anatomic level) was described by measurements of rib arc length, chord length, enclosed area, maximum curvature, and frontal and lateral angulations. Patients were divided into four groups: 19 with a single right thoracic curve, 15 with a single left lumbar or thoracolumbar curve, 22 with double curves, and 15 with a curve with less than 10 degrees Cobb angle. In the control group and the group with minimal scoliosis, there was no statistically significant rib asymmetry. Among the patients with scoliosis, 11 of 19 patients with right single thoracic curves had rib arc lengths greater on the right side at the curve apex, and nine of 15 patients with left lumbar scoliosis had longer ribs on the left side in the corresponding region of the thoracic spine. Eleven of 22 patients with double curves had symmetrical rib lengths (within +/- 3%), the other 11 had ribs longer on the left. These proportions should not have occurred by chance (p less than 0.001). The mean rib length difference in patients with single thoracic curves was 1.39% (right longer than left), in single lumbar curves it was 3.57% (left longer than right), and in double curves 3.18% (left longer than right). These differences between the groups of patients and control subjects were statistically significant (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evidence-based strategies for preventing drug administration errors during anaesthesia

We developed evidence-based recommendations for the minimisation of errors in intravenous drug administration in anaesthesia from a systematic review of the literature that identified 98 relevant references (14 with experimental designs or incident reports and 19 with reports of cases or case series). We validated the recommendations using reports of drug errors collected in a previous study. One general and five specific strong recommendations were generated: systematic countermeasures should be used to decrease the number of drug administration errors in anaesthesia; the label on any drug ampoule or syringe should be read carefully before a drug is drawn up or injected; the legibility and contents of labels on ampoules and syringes should be optimised according to agreed standards; syringes should (almost) always be labelled; formal organisation of drug drawers and workspaces should be used; labels should be checked with a second person or a device before a drug is drawn up or administered.     

Penile measurements in normal adult Jordanians and in patients with erectile dysfunction

The purpose of this work was to determine penile size in adult normal (group one, 271) and impotent (group two, 109) Jordanian patients. Heights of the patients, the flaccid and fully stretched penile lengths were measured in centimeters in both groups. Midshaft circumference in the flaccid state was recorded in group one. Penile length in the fully erect penis was measured in group two. In group one mean midshaft circumference was 8.98+/-1.4, mean flaccid length was mean 9.3+/-1.9, and mean stretched length was 13.5+/-2.3. In group two, mean flaccid length was 7.7+/-1.3, and mean stretched length was 11.6+/-1.4. The mean of fully erect penile length after trimex injection was 11.8+/-1.5. In group 1 there was no correlation between height and flaccid length or stretched length, but there was a significant correlation between height and midpoint circumference, flaccid and stretched lengths, and between stretched lengths and midpoint circumference. In group 2 there was no correlation between height and flaccid, stretched, or fully erect lengths. On the other hand, there was a significant correlation between the flaccid, stretched and fully erect lengths. Comparing group 1 and group 2, the patients in group 1 were slightly older than in group 2 (P=0.035), but there was no significant difference in their height. However, there was a significant difference regarding the mean flaccid length 9.3 vs 7.7 (P=0.001), and the mean stretched length 13.5 vs 11.6 (P=0.000). We divided both groups into those who are less than 40 y of age, and over 40 y old. There was no statistical difference in the stretched and flaccid lengths between the younger and older individuals in each group. However, when we compared the stretched and flaccid lengths in those of less than 40 y old in group 1 and 2, a significant difference was noticed. Similarly, a significant difference in the stretched and flaccid lengths in those patients over 40 y of age was also present.     

Comparison of Payne and Scott operations for morbid obesity.

One hundred five patients were operated upon for morbid obesity using accepted criteria for operation. Forty-five patients with the Payne operation (35 cm of jejunum anastomosed end-to-side to 10 cm of ileum) were compared with 45 patients having the Scott operation (30 cm of jejunum anatomosed end-to-end to 15 cm of ileum with the proximal cut end of ileum vented into the transverse colon). The weight loss in the first two years was similar, although the Scott procedure patients lost slightly more weight. Comparison of the two groups by a new grading system also showed little difference in the two procedures. The Scott procedure takes longer and subjects the patient to an additional anastomosis. Study of a smaller group of patients having the Scott operation with varying lengths of jejunum and ileum indicates that there should not be less than 30 cm of jejunum nor more than 15 cm of ileum left in continuity. The length of jejunum is particularly important in the production of weight loss, and accurate intraoperative measurement of intestinal length is crucial. In the postoperative period the length of functional jejunum and ileum can be determined by upper gastrointestinal barium roentgenograms.     

Tetracycline fluorescence in uremic and primary hyperparathyroid bone

Twenty-five patients with end-stage renal disease, nine of whom were receiving pharmacologic doses of vitamin D, and seventeen patients with primary hyperparathyroidism underwent bone biopsy following a three-day course of tetracycline administration. The mean width of the fluorescent tetracycline bands were significantly greater in the bones of patients with uremia than in those with primary hyperparathyroidism. This difference was due to wide labels present in the patients with uremia who had not been treated with vitamin D, as no differences existed in mean label widths of patients with uremia who had received this compound and the patients with primary hyperparathyroidism. Comparison of the maximum label widths distinguished not only primary hyperparathyroid patients from those with uremia, but uremic patients who had recieved vitamin D from those who had not been so treated. Quantitative microscopy of standard, nonfluorescent histologic features failed to make this latter distinction. These data are consistent with the presence of a wide zone of instantaneously fluorescing material in uremic bone following tetracycline administration, which does not relate to bone apposition occurring during antibiotic administration. This phenomenon probably represents a delay in mineral maturation which is normalized by vitamin D. Furthermore, it is apparent that the use of a continuously administered (single) tetracycline label will result in an overestimation of bone formation rates, particularly in osteomalacic states.     

The etiology of pectus carinatum involves overgrowth of costal cartilage and undergrowth of ribs

Purpose

We compared the length of costal cartilage and rib between patients with symmetric pectus carinatum and controls without anterior chest wall protrusion, using a 3-dimensional (3D) computed tomography (CT) to evaluate whether the overgrowth of costal cartilage exists in patients with pectus carinatum.

Subjects and methods

Twenty-six patients with symmetric pectus carinatum and matched twenty-six controls without chest wall protrusion were enrolled. We measured the full lengths of the 4th–6th ribs and costal cartilages using 3-D volume rendering CT images and the curved multiplanar reformatted (MPR) techniques. The lengths of ribs and costal cartilages, the summation of rib and costal cartilage lengths, and the costal index [length of cartilage/length of rib * 100 (%)] were compared between the patients group and the control group at 4th–6th levels.

Results

The lengths of costal cartilage in patient group were significantly longer than those of control group at 4th, 5th and 6th rib level. The lengths of ribs in patient group were significantly shorter than those of control group at 4th, 5th and 6th rib level. The summations of rib and costal cartilage lengths were not longer in patients group than in control group. The costal indices were significantly larger in patients group than in control groups at 4th, 5th and 6th rib level.

Conclusion

In patients with symmetric pectus carinatum, the lengths of costal cartilage were longer but the lengths of rib were shorter than those of controls. These findings may supports that the overgrowth of costal cartilage was not the only factor responsible for pectus carinatum.     

Labeling studies on cortical bone formation in the antlers of red deer (Cervus elaphus)

The formation and mineralization process of antlers, which constitute the fastest growing bones in vertebrates, is still not fully understood. We used oxytetracycline injections to label different stages of bone formation in antlers of 14 red deer between days 28 and 156 of antler growth. Results show that initially a trabecular scaffold of woven bone is formed which largely replaces a pre-existing scaffold of mineralized cartilage. Lamellar bone is then deposited and from about day 70 onwards, primary osteons fill in the longitudinal tubes lined by the scaffold in a proximal to distal sequence. Mineral apposition rate (MAR) in early stages of primary osteon formation is very high (average 2.15 μm/d). Lower MARs were recorded for later stages of primary osteon formation (1.56 μm/d) and for the smaller secondary osteons (0.89 μm/d). Results suggest a peak in mineral demand around day 100 when the extent of mineralizing surfaces is maximal. A few secondary osteons were formed in a process of antler modeling rather than remodeling, as it occurred simultaneously with formation of primary osteons. The degree of cortical porosity reflects a reduction in MAR during later stages of osteonal growth, whereas cortical thickness is determined earlier. Injections given when the antlers were largely or completely clean from velvet produced no labels in antler bone, strongly suggesting that antlers are dead after velvet shedding. The rapidity of antler mineralization and the short lifespan of antlers make them an extraordinary model to assess the effects of chemicals impairing or promoting bone mineralization.     

Bone remodeling in predialysis chronic renal failure: how does the choice of index for mineralizing surface influence the interpretation?

To study how calculating bone dynamics with different indices of mineralizing surface (MS) may influence the interpretation of bone remodeling in chronic renal failure (CRF) and to discuss which of three often used indices may be closest to the true MS, we compared bone histomorphometry in predialysis patients with moderate (se-creatinine less than 400 mumol/liter) and advanced CRF. All were double-labeled with tetracycline and had no stainable bone aluminum. Bone dynamics were calculated with MS = double-labeled (dLS) + single-labeled surface (sLS), MS = dLS + sLS/2, and MS = dLS. As sLS was twice that of dLS in both groups and the label interval was only 10 days, most single labels were probably double labels, but unseparable due to wide and unsharp labels resulting from high rather than low bone turnover. Bone volume was the same in both groups, while osteoid and resorption indices, sLS, and bone formation rate (with MS = dLS + sLS) were increased in advanced CRF. dLS + sLS is higher than the true MS, but more representative for MS than dLS + sLS/2, with the true value between these two indices. Bone resorption, osteoid formation, and mineralization remain in balance even in advanced CRF. Osteomalacia is hardly the consequence of CRF alone.     

Medication errors--new approaches to prevention

Medication errors in pediatric anesthesia represent an important risk to children. Concerted action to reduce harm from this cause is overdue. An understanding of the genesis of avoidable adverse drug events may facilitate the development of effective countermeasures to the events or their effects. Errors include those involving the automatic system of cognition and those involving the reflective system. Errors and violations are distinct, but violations often predispose to error. The system of medication administration is complex, and many aspects of it are conducive to error. Evidence-based practices to reduce the risk of medication error in general include those encompassed by the following recommendations: systematic countermeasures should be used to decrease the number of drug administration errors in anesthesia; the label on any drug ampoule or syringe should be read carefully before a drug is drawn up or injected; the legibility and contents of labels on ampoules and syringes should be optimized according to agreed standards; syringes should always be labeled; formal organization of drug drawers and workspaces should be used; labels should be checked with a second person or a device before a drug is drawn up or administered. Dosage errors are particularly common in pediatric patients. Causes that should be addressed include a lack of pediatric formulations and/or presentations of medication that necessitates dilution before administration or the use of intravenous formulations for oral administration in children, a frequent failure to obtain accurate weights for patients and a paucity of pharmacokinetic and pharmacodynamic data. Technological innovations, including the use of bar codes and various cognitive aids, may facilitate compliance with these recommendations. Improved medication safety requires a system-wide strategy standardized at least to the level of the institution; it is the responsibility of institutional leadership to introduce such strategies and of individual practitioners to engage in them.     

Incidence and bone biopsy findings of atypical femoral fractures

Bisphosphonates are widely used in the treatment of osteoporosis. It has been suggested that bisphosphonate treatment may be associated with atypical femoral fractures (AFFs), severely suppressed bone turnover rate, and decreased mineralization. We studied bone properties using bone quantitative histomorphometry and Fourier transform infrared spectroscopic imaging (FTIRI) on patients with AFFs. Further, the incidence of AFFs was estimated. Patient records of Kuopio University Hospital, Finland from January 2007 to June 2009 were reviewed to identify all patients who had sustained and had been operated for AFF (n = 8). The incidence of AFFs among patients on bisphosphonates was 0.61 fractures/1,000 patients per year, compared to 0.0067/1,000 per year among untreated patients. The patients that underwent bone biopsy (n = 4) were postmenopausal women (aged 55.5–81.1 years) who had been treated with bisphosphonates for over 4 years. Histomorphometry revealed low trabecular bone volume. Bone formation and resorption parameters tended to be low. Trabecular bone single labels were detected in one patient in the region of interest. In the extended label search, trabecular bone double labels were found in two patients. Based on FTIRI results, higher phosphate-to-amide I ratio and collagen maturity were found compared to normal samples. The heterogeneity of phosphate-to-amide I ratio was low. Overall incidence of atypical femoral fractures is low. The poor fracture resistance in some patients on long-term bisphosphonate-therapy could be explained by low bone formation, and changes in bone composition, i.e., higher degree of mineralization, increased collagen maturity, and decreased heterogeneity of the degree of mineralization.     

Normal bone particles are preferentially resorbed in the presence of osteocalcin-deficient bone particlesIn vivo

Summary In anin vivo model of osteoclastic bone resorption, we previously showed that osteocalcin-deficient bone particles (BPs), derived from warfarin-treated rats, were resorbed 50% as well as normal BPs and that they recruited fewer osteoclastic cells with decreased tartrate-resistant acid phosphatase (TRAP) activity. In order to determine the specificity of the resorption response, we evaluated the fate of implanted mixtures of normal and osteocalcin-deficient BPs. Normal and warfarin-treated donor rats were prelabeledin vivo with oxytetracycline to permit identification of BPs from either source. Normal, osteocalcin-deficient, and 50∶50 mixtures of BPs (either labeled or unlabeled) were implanted into normal rats and recovered 12 days later for enzymatic (TRAP) and nondecalcified histomorphometric analyses. The incorporated oxytetracycline had no signficant effect on resorption of bone particles. The recovered osteocalcin-deficient BPs were surrounded by fewer osteoclastic cells, were resorbed less, and contained less extractable TRAP activity than normal BPs. In mixed BP implants with normal and osteocalcin-deficient BPs, each type of bone particle elicited the same tissue response as when implanted separately. Remarkably, the different particles evoked dissimilar osteoclastic responses and were resorbed to different extents, even when adjacent within the same implant. These data suggest that osteocalcin may act as a substrate signal for resorption and that osteocalcin in the normal BPs does not influence the cellular response to adjacent osteocalcin-deficient BPs.     

Tetracyclines Inhibit Rat Osteoclast Formation and Activity In Vitro and Affect Bone Turnover in Young Rats In Vivo

An experiment was designed to investigate whether systemic administration of tetracyclines (TCs) as bone fluorochrome labels could interfere with bone modeling in vivo and inhibit osteoclast formation and activity in vitro. Cell cultures of rat bone marrow macrophages revealed that TC and oxytetracycline inhibited osteoclastogenesis and bone resorption and stimulated apoptosis. Forty rats in five groups were treated with saline, calcein green, alizarin red S, TC, or oxytetracycline. Their tibias were used for histomorphometric analysis, including bone static, dynamic, and resorption parameters in the tibial proximal metaphysis. No significant differences in bone volume per tissue volume, trabecular number, trabecular thickness, trabecular separation, bone formation rate per bone surface, mineralizing surface, or mineral apposition rate were observed. TC or oxytetracycline decreased eroded surface, number of osteoclasts per bone perimeter, and osteoclast surface per bone surface by about 50%. The results demonstrated that TC and oxytetracycline inhibit rat osteoclast formation and activity in vitro, and histomorphometric parameters involved in bone turnover may be affected by the use of oxytetracycline and TC as fluorescent bone labels in vivo.