Characterization of gut microbiota and short-chain fatty acid in breastfed infants with or without breast milk jaundice.

This study aims to investigate the gut microbiota and metabolites in breastfed infants with breast milk jaundice (BMJ) using gut microbiome-metabolomics. Breastfed newborns diagnosed with BMJ and those without BMJ (control group) were enrolled. Faecal samples were collected from the participants and subjected to high-throughput sequencing of the 16s rDNA V3 and V4 regions of the gut flora and metabolomics of short-chain fatty acids (SCFAs). Proteobacteria, Fimicutes and Actinobacteria were the main bacteria at the phylum level. Eshcerichia-Shigella and Enterobacteriacea were the main bacteria at the genus level. The difference between the two groups was compared. Compared to the control group, the amount of Streptococcus was significantly increased while the amount of Enterococcus was significantly decreased in the faeces from infants with BMJ. Functional prediction analysis of 16S found that biosynthesis of penicillin and cephalosporin significantly increased in the BMJ group. Gas chromatography-mass spectrometry detection of SCFAs revealed that levels of acetic acid and propionic acid were significantly lower in the BMJ group than in the control group. The reduced levels of acetic acid and propionic acid may be related to the increase in Streptococcus and decrease in Enterococcus, both of which may contribute to BMJ.

[Retroauricular robotic thyroidectomy: a preliminary report of 5 cases].

Objective: To explore the feasibility of retroauricular robotic thyroidectomy and introduce the experience and lessons. Methods: From May 2018 to December 2018, 5 consecutive cases underwent gasless retroauricular robotic thyroidectomy by using Davinci Si system at Beijing United Family Hospital, including 1 male and 4 females, aged from 18 to 37 years old. And they were retrospectively reviewed and analyzed. Among them, one case was a recurrence of cervical lympy nodes after total thyroidectomy for thyroid cancer. Results: Among 5 patients (mean age 32.4 years, mean tumor size 1.3 cm), one patient underwent unilateral thyroid lobectomies, 3 patients did total thyroidectomy and 4 patients did neck dissection. All patients had papillary thyroid carcinomas (PTC). The average time for unilateral retroauricular robotic thyroidectomy was 375 min. Intraoperative conversion to open surgery happened in one patient. Postoperative vocal cord paralysis and hypocalcemia developed in one of the patients. Conclusion: Retroauricular robotic thyroidectomy is feasible for selected patients and would be a potential alternative approach in remote-access approaches for thyroid surgery.

Ultrafast temporal-spatial dynamics of amorphous-to-crystalline phase transition in Ge2Sb2Te5 thin film triggered by multiple femtosecond laser pulses irradiation.

Studies have shown that the crystallization phase state of Ge2Sb2Te5 (GST) can be reversibly modulated by femtosecond (fs) laser multiple pulses, which have excellent applications in reconfigurable multi-level operation fields. In this study, the temporal-spatial crystalline evolution dynamics of amorphous GST film is investigated during two fs laser pulses excitation through a pump-probe shadowgraph imaging technique. A quasi-amorphous phase state, which is different from that in the initial as-deposited amorphous GST, is emerged through the first fs laser pulse excitation with a pulse energy lower than crystallization threshold. The experimental results reveal that a crystallization enhancement effect can be induced through the second pulse excitation based on this quasi-amorphous surface structure. The stimulative cluster generated in the quasi-amorphous reduces the amorphous-to-crystalline phase transition threshold for the second fs laser pulse irradiation. The spatially-resolved phase-transition threshold extension effect in a horizontal direction is proposed with the increasing pulse number to summarize the mechanism of the crystallization enhancement effect. The specific-grain-appearance (coarse grains and fine grains representing different phase transition approach) distributed area induced by single and double fs laser pulses irradiation are experimentally demonstrated corresponding to threshold extension theory.

[Clinicopathological characteristics of type 2 diabetes mellitus complicated with colorectal cancer].

Objective: To analyze the clinicopathological features of type 2 diabetes mellitus complicated with colorectal cancer (DCRC). Methods: A case-control study was conducted. Inclusion criteria: (1) hospitalized patients receiving fibrocolonoscopy; (2) adenocarcinoma and mucinous adenocarcinoma diagnosed by pathology; (3) with preoperative cTNM clinical staging; (4) colorectal cancer patients undergoing surgical treatment; (5) with postoperative pTNM staging; (6) no smoking or drinking habits. Exclusion criteria: (1) familial adenomatous polyposis (FAP); (2) Lynch syndrome; (3) carcinoma of anal canal and perianal carcinoma; (4) multiple primary cancer; (5) with serious cardiocerebrovascular diseases or multiple organ failure. Clinicopathlogical data of 32 DCRC patients who were diagnosed and treated in Peking University Shougang Hospital from December 2017 to December 2018 were retrospectively collected and analyzed. Forty nondiabetic colorectal cancer (CRC) patients during the same period were selected as control group according to the sex ratio and the age difference less than 5 years. Student's t test and χ(2) test were used to compare the difference between the two groups in baseline clinicopathological data, clinical test results, tumor markers and infiltration status of T cells in tumor immune microenvironment. Results: Among 32 DCRC patients, 24 were males and 8 were females with a mean age of (63.0±1.7) years; among 40 CRC patients, 30 were males and 10 were females with a mean age of (60.5±1.6) years. The duration of diabetes mellitus in DCRC patients (from the diagnosis of diabetes mellitus to the diagnosis of colorectal cancer) was (9.2±1.3) years. The body mass index (BMI) of DCRC group was significantly higher than that of CRC group [(24.8±0.6) kg/m(2) vs. (23.2±0.4) kg/m(2), t=2.372, P=0.020]. There were no significant differences in other baseline data (sex, age, primary site of tumor, R0 resection rate, pathological stage, pathological type, differentiation degree of tumor, preoperative intestinal obstruction) between the two groups (all P>0.05). Serum triglyceride level in DCRC group was higher than that in CRC group [(2.1±0.2) mmol/L vs. (1.5±0.1) mmol/L, t=3.085, P=0.003], while hemoglobin [(120.3±5.2) g/L vs. (132.7±2.8) g/L, t=-2.224, P=0.029], anti- thrombin III [(94.2±3.7)% vs. (103.5±2.4)%, t=-2.197, P=0.031], and red blood cell count [(4.2±0.1)×10(12)/L vs. (4.5±0.1)×10(12)L, t=-2.055, P=0.044] were all lower than those in CRC group. The preoperative carcinoembryonic antigen (CEA) level in DCRC group was higher than that in CRC group [(50.3±21.8) µg/L vs. (5.6±1.0) µg/L, t=2.339, P=0.022]. There were no significant differences in preoperative levels of other four tumor molecular markers (CA199, CA242, CA724 and CA125) between the two groups (all P>0.05). The expression of Foxp3 [specific markers of CD4+, CD25+ regulatory T cells (Treg)] in DCRC group was higher than that in CRC group [(82.7±6.2) cell/HPF vs. (62.6±4.9) cell/HPF, t=2.586, P=0.012]. There were no significant differences in the infiltration of CD4, CD8, PD-1 and PD-L1 positive cells between two groups (all P>0.05). Conclusions: The average diabetic history of DCRC patients is nearly 10 years. They have higher BMI and serum CEA level, and more Treg cell infiltration in the tumor. Close attention should be paid to these patients in clinical practice.

[The Value of SMI in the Evaluation of interventional therapy of liver cancer].

Objective: To evaluate the value of super microvascular imaging(SMI) for evaluating the effect of interventional therapy of liver cancer. Methods: A total of 30 patients with 40 leisions were enrolled in this study, from the tumor intervention department in the third affiliated hospital of suzhou university.This patients were underwent TACE, after the treatment 1 month, CDFI, SMI, and CT were study respectively. Using the continuity correction McNemar matching chi-square test, with P < 0.05 for the standard , CDFI and SMI shows the difference in monitoring the microvascular imaging in and around the tumors leisions. Results: A total of 30 patients, 12 cases were primary liver cancer (7 cases combined with liver cirrhosis), 18cases were metastatic liver cancer; 30 cases including 25 single and 5 multiple. Significant difference were found between CT and SMI in detecting blood flows inside the lesion (χ² = 8.642 9, P < 0.05), and were also found between CT and CDFI in detecting blood flows inside the lesion (χ² = 16.961 5, P < 0.05). The AUROC, sensitivity, specificity, accuracy, PPV and NPV of CDFI were 0.647, 29.4%、100%、29.4%、100%、20.0%, while in SMI were 0.809, 61.8%、100%、61.7%、100%、31.5%, respectively. Conclusions: SMI SMI can detect the microvascular inside the lesions. This new method was superior to CDFI, achieving the same effect as CT.

Predictive value of plasma galectin-3 in patients with chronic heart failure.

AIM: To study the predictive value of plasma galectin-3 in patients with chronic heart failure (CHF). MATERIALS AND METHODS: Patients with CHF (New York Heart Association functional class II-IV) caused by coronary heart disease were recruited. The levels of plasma galectin-3 and NT-proBNP were measured by enzyme-linked immuno sorbent assay. Echocardiography was performed to determine the diastolic left atrial diameter (LAD), left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF). Receiver-operating characteristic (ROC) curve was used to analyze the prognostic value of galectin-3 or NT-proBNP for CHF. RESULTS: The level of galectin-3 was significantly higher in NYHA functional class III and IV compared with that in control (p < 0.05 and p < 0.01, respectively). The level of plasma galectin-3 was positively correlated with LAD (r = 0.271, p < 0.05) and LVEDD (r = 0.480, p < 0.01), but negatively correlated with LVEF (r = -0.683, p < 0.01). The level of plasma NT-proBNP was positively correlated with LAD (r = 0.481, p < 0.01) and LVEDD (r = 0.270, p < 0.05), but negatively correlated with LVEF (r = -0.516, p < 0.01). AUC was 0.798 when the level of plasma galectin-3 was more than 7.52 ng/ml. The sensitivity to predict CHF was 62.9%, and the specificity was 90%. AUC was 0.901 when the level of plasma NT-proBNP was more than 1143 pg/ml. The sensitivity to predict CHF was 92.8% and the specificity was 85%. CONCLUSIONS: The level of plasma galectin-3 is related to the changes of left ventricular structure and function, indicating that galectin-3 may have been involved in the process of left ventricular remodeling in CHF. The specificity of galectin-3 to predict CHF is higher than NT-proBNP, but not the sensitivity.

Synthesis of low-melting-point metallic nanoparticles with an ultrasonic nanoemulsion method.

A one-step, economical nanoemulsion method has been introduced to synthesize low-melting-point metallic nanoparticles. This nanoemulsion technique exploits the extremely high shear rates generated by the ultrasonic agitation and the relatively large viscosity of the continuous phase - polyalphaolefin (PAO), to rupture the molten metal down to diameter below 100 nm. Field's metal nanoparticles and Indium nanoparticles of respective average diameters of 15 nm and 30 nm have been obtained. The nanoparticles size and shape are determined by transmission electron microscopy (TEM). Their phase transition behavior is examined using a differential scanning calorimeter (DSC). It is found that these nanoparticles dispersed in PAO can undergo reversible, melting-freezing phase transition, and exhibit a relatively large hysteresis. The experimental results suggest that the nanoemulsion method is a viable route for mass production of low-melting nanoparticles.

Catalyst-free growth of quasi-aligned nanorods of single crystal Cu3Mo2O9 and their catalytic properties.

We propose a simple and catalyst-free method to grow quasi-aligned single crystalline Cu(3)Mo(2)O(9) nanorods in terms of a mechanism differing from the conventional vapor-solid (VS) and vapor-liquid-solid (VLS) ones for chemical vapor deposition (CVD) methods by directly heating Cu foils in a mixed atmosphere of MoO(3) vapor and air. High quality Cu(3)Mo(2)O(9) nanorods can be simply grown in a temperature range from 450 to 550 degrees C whose diameter, length, and distribution density are dependent on both heating temperature and time. Interestingly, the growth rate at 550 degrees C drops significantly after 6 h. All nanorods grow along the [010] direction. On the basis of a proposed growth model, the nucleation of Cu(3)Mo(2)O(9) nanorods is believed to be governed by formation of initial polycrystalline Cu(x)O protuberances with nanoscale diameters on Cu foils which may act as growth "templates". This novel method can be applied to grow other similar tertiary transition metal oxide nanostructures on substrates with large sizes. Most importantly, these Cu(3)Mo(2)O(9) nanorods decrease the ignition temperature of Printex U model soot from 600 to 438 degrees C, being in between 200 and 450 degrees C of the exhaust of diesel-powered combustion engines, which are therefore expected to be a potential efficient and environmentally friendly catalyst for diesel exhaust combustion.

Furanochromone radical cations: generation, characterization and interaction with DNA.

The radical cations of naturally occurring furanochromones visnagin (VI) and khellin (KH) have been generated and identified for the first time by use of laser flash photolysis and pulse radiolysis techniques. The lifetimes of VI(.+) and KH(.+) are determined as approximately 6 and approximately 35 micros under these conditions, respectively. Direct 308-nm excitation of VI in aqueous buffer at physiological pH results in monophotonic photoionization to generate VI(.+), with a quantum yield of 0.075, which is much higher than that of 8-methoxypsoralen and KH under identical conditions. Though VI(.+) is a more powerful oxidant than KH(.+), both of them react with guanosine mononucleotide (k=1.2x10(9) and 3.8x10(7) dm(3) mol(-1) s(-1), respectively) via electron transfer to give the guanine radical cation. Furthermore, selective oxidation of guanine in single and double strand DNA by VI(.+) was also observed. These novel findings suggest that electron transfer reactions involving furanochromone radical cations may be of considerable importance in furanochromone photochemotherapy.

Triplet state mechanism for electron transfer oxidation of DNA.

The interaction of anthraquinone-2-sulfonate with nucleotides and DNA in acetonitrile and acetonitrile water solvent mixture have been studied using KrF laser photolysis aimed at elucidation of the reaction mechanism. Laser spectroscopy directly demonstrates that the initial species from interaction of anthraquinone-2-sulfonate with nucleotides are radical cations of nucleotides and radical anion of anthraquinone-2-sulfonate. In addition, formation of ion pair from interaction of any of nucleotides with anthraquinone-2-sulfonate is synchronous with decay of triplet anthraquinone-2-sulfonate, which has provided dynamic evidence for initiation of electron transfer from DNA bases to triplet anthraquinone-2-sulfonate. Moreover, direct observation of stabilized DNA guanyl radical cation from interaction of anthraquinone-2-sulfonate with DNA has provided initial evidence for selective cleavage of DNA at guanine moiety. The solvent-separated ion pairs in acetonitrile have evidently dissociated into free ions, thereby enabling independent study of the behavior of guanyl radical cations and radical anion of anthraquinone-2-sulfonate.

Osteomalacia due to vitamin D depletion: a neglected consequence of intestinal malabsorption.

PURPOSE: Osteomalacia due to vitamin D depletion is believed to be rare in the United States because of the routine fortification of milk and other dairy products with vitamin D. We present a series of patients with histologically verified osteomalacia due to vitamin D depletion to emphasize the need for more careful and systematic surveillance of patients at risk of this metabolic bone disease. METHODS: Between 1989 and 1994, 17 patients with osteomalacia due to vitamin D depletion were seen in the Bone and Mineral Division of Henry Ford Health System, Detroit. All patients had a transiliac bone biopsy after in vivo double tetracycline labeling. Biochemical indexes of vitamin D nutritional status, parathyroid function, markers of bone turnover, and bone mineral density were assessed at the time of bone biopsy. The duration of symptoms, the lag between the cause of vitamin D depletion and the development of symptoms, and the radiologic findings were recorded. RESULTS: Osteomalacia was suspected by the referring physician in only 4 of the 17 patients, although a gastrointestinal disorder that can lead to vitamin D depletion was present in every patient. Thirteen of the patients had sustained at least one osteoporotic fracture (wrist, spine, or hip), and most had low appendicular and axial bone mineral density. All patients had one or more biochemical abnormalities consistent with vitamin D depletion. In 4 patients, a progressive rise in the serum alkaline phosphatase level was recorded but was not investigated until the patient presented with bone pain, muscle weakness, or fracture. CONCLUSIONS: Osteomalacia due to vitamin D depletion appears not to be suspected or diagnosed promptly in susceptible patients, perhaps because their physicians were not sufficiently aware of this condition.

Reduced vitamin D receptor expression in parathyroid adenomas: implications for pathogenesis.

BACKGROUND AND OBJECTIVES: Parathyroid adenomas discovered fortuitously grow very slowly and their cell birth rate greatly declines, features explicable by an initial increase in secretory set-point. In the nodules of severe uraemic parathyroid hyperplasia, there is an increased set-point and decreased expression of both the calcium sensing receptor (CaSR) and the vitamin D receptor (VDR). Accordingly, we examined VDR and CaSR expression in parathyroid adenomas. PATIENTS AND DESIGN: We studied 24 patients with primary hyperparathyroidism with a wide range of vitamin D nutritional status (plasma 25-hydroxyvitamin D range 10-107 nmol/l). Eighteen patients discovered by biochemical screening were enrolled in a natural history or treatment option study, and six additional US patients matched a group studied concurrently in India with low plasma 25-hydroxyvitamin D level (< 37 nmol/l). MEASUREMENTS: Receptor expression was determined by immunocytochemistry in each tumour and in 11 cases also in adjacent nonadenomatous tissue. VDR expression was reported as the proportion of positive cells (strongly rather than weakly stained) determined by systematic random sampling and CaSR expression as grey scale values of staining intensity in arbitrary units determined by image analysis. RESULTS: The mean (SD) proportion of cells positive for VDR was 2.93 (2.17)% in the parathyroid adenomas and 95.7 (5.10)% in the nonadenomatous tissue. In about two-thirds of the cases VDR positive cells could have been remnants of a normal gland, but in the remaining one-third they were too numerous to be accounted for by this explanation. The mean (SD) intensity of CaSR expression was 151 (4.71) units in parathyroid adenomas and 218 (5.0) units in nonadenomatous tissue (P<0.001). The frequency of VDR loss and the changes in CaSR immunohistochemistry were unrelated to race, sex, or disease severity, except that the reduction in CaSR was significantly greater in patients with normal vitamin D nutrition (32.1% vs. 29.0%). CONCLUSIONS: (1) There is reduction of vitamin D receptor expression in almost all cells in parathyroid adenomas. This defect was probably present in the founder cell of the tumour clone in the majority of cases. Since mutations in the vitamin D receptor gene have been sought but not found, possible explanations include inhibition of vitamin D receptor gene transcription, decreased amount of the corresponding mRNA, or failure of normal translation. (2) Reduction in calcium sensing receptor could be either the primary defect or (more commonly) secondary to loss of vitamin D receptor and is of sufficient magnitude to account for the increase in secretory set-point and consequent asymptotic growth and stable clinical course.

Fast repairing of oxidized OH radical adducts of dAMP and dGMP by phenylpropanoid glycosides from Scrophularia ningpoensis Hemsl.

AIM: To investigate the antioxidative activity of the constituents of the roots of Scrophularia ningpoensis (Chinese name: Xuanshen). METHODS: The main compounds from the roots of Scrophularia ningpoensis were isolated and identified by chromatography and FABMS, NMR etc. Using the techniques of pulse radiolysis, the electron transfers from iridoid glycosides (IG) or phenylpropanoid glycosides (PG) to oxidized OH radical adducts of 2'-deoxyadenosine-5'-monophosphate acid (dAMP) or 2'-deoxyguanosine-5'-monophosphate acid (dGMP) were observed. RESULTS: Two IG: harpagoside and harpagide, two PG: angoroside C and acteoside were obtained as the main hydrophilic constituents of the plant. At 0.1 mmol/L concentration, angoroside C and acteoside were able to repair the oxidized OH adducts dAMP and dGMP significantly. However, harpagoside and harpagide had no such effect. The electron transfer rate constants of angoroside C with dAMP and dGMP were 4.2 x 10(8) and 10.3 x 10(8) L.mol-1.s-1; the electron transfer rate constants of acteoside with dAMP and dGMP were 5.3 x 10(8) and 20.2 x 10(8) L.mol-1.s-1. CONCLUSION: PG from Scrophularia ningpoensis have a potent antioxidative activity for reducing of the oxidized OH adducts of dAMP and dGMP.

Interaction of hydroxycinnamic acid derivatives with the Cl3COO radical: a pulse radiolysis study.

The electron transfer reactions between the trichloromethylperoxyl radical (Cl3COO*) and hydroxycinnamic acid derivatives, including chlorogenic acid, sinapic acid, caffeic acid, ferulic acid and 3,4-(methylenedioxy)cinnamic acid, have been studied by pulse radiolysis. The hydroxycinnamic acid derivatives, especially sinapic acid, are identified as good antioxidants for reduction of Cl3COO* via electron transfer reactions. From buildup kinetic analysis of phenoxyl radical, the rate constant for reaction of Cl3COO* with sinapic acid has been determined to be 8.2x10(7) dm3 mol(-1) s(-1), while the rate constants of electron transfer from other hydroxycinnamic acid derivatives to Cl3COO* were obtained to be about 2x10(7) dm3 mol(-1) s(-1). The reaction of 3,4-(methylenedioxy) cinnamic acid with Cl3COO* was investigated as an evidence for the electron transfer mechanism.

Mineralized bone loss at different sites in dialysis patients: implications for prevention.

To characterize the magnitude and location of mineralized bone loss, 40 patients (20 men, 20 women, 29 white, 11 black) with clinically significant renal osteodystrophy who could be unambiguously classified based on histologic criteria as having osteitis fibrosa (OF; 20 cases) or osteomalacia (OM; 20 cases) were studied; they had been on maintenance hemodialysis for 4.6 +/- 3.0 yr. One hundred forty-two healthy women of similar age and ethnic composition served as control subjects. In all subjects, the proportions of mineralized bone, osteoid, and porosity (nonbone soft tissue) were measured separately in cortical and cancellous bone tissue, from intact full-thickness biopsies of the ilium, representative of the axial skeleton. The results were related to the volumes of cortical and cancellous bone tissue separately and to the volume of the entire biopsy core. Approximately three-quarters of the patients had measurements in the appendicular skeleton by single photon absorptiometry of the radius and morphometry of the metacarpal. Disease effects did not differ significantly between ethnic groups. Mineralized cortical bone volume (per unit of core volume) was reduced by approximately 45% in both patient groups. Mineralized cancellous bone volume was significantly increased by 36% in the patients with OF and nonsignificantly reduced by 9% in the patients with OM; however, the reduction in the latter patients was significant in relation to tissue volume. The combined total deficit for both types of iliac bone was approximately 20% in the patients with OF and approximately 40% in the patients with OM. Significant reductions in appendicular cortical bone were demonstrated in both patient groups at both measurement sites. Regardless of the current histologic classification, the major structural abnormality in the skeleton is generalized thinning of cortical bone due to increased net endocortical resorption, the most characteristic effect on bone of hyperparathyroidism. Protection of the skeleton from the adverse consequences of renal failure will require therapeutic intervention in patients with no symptoms of either renal or bone disease.

Effects of ethnicity and age or menopause on the remodeling and turnover of iliac bone: implications for mechanisms of bone loss.

We measured histologic indices of bone remodeling and turnover separately on the cancellous, endocortical, and intracortical subdivisions of the endosteal envelope, and on the combined total surface, in transiliac bone biopsies obtained after double tetracycline labeling in 142 healthy women, aged 20-74 years, 34 black and 108 white, 61 premenopausal and 81 postmenopausal. The data were analyzed by two-way analysis of variance of the four groups defined by age/menopause and ethnicity and by linear regression of the major variables on age. None of the interaction terms was significant and none of the regression slopes on age differed between blacks and whites, indicating that, as for the previously reported structural indices, the effects of ethnicity and of age/menopause are independent. Accordingly, the data were also analyzed separately for the effect of ethnicity (pre- and postmenopausal combined) and age/menopause (blacks and whites combined). The analyses led to the following conclusions. (1) The geometric mean bone formation rate on the combined total surface was 25% lower in blacks than in whites; other histologic differences between ethnic groups were inconsistent between surfaces. (2) Serum osteocalcin (OC) but not bone-specific alkaline phosphatase (BSAP) was lower by about 15% in blacks than in whites. (3) The lower bone turnover in blacks is most likely in the directed rather than in the stochastic component because of a higher bone mass and consequent reduced susceptibility to fatigue damage. (4) All Class 1 bone formation variables and the three resorption indices were significantly higher in the postmenopausal compared with the premenopausal subjects, reflecting a 33% increase in activation frequency. (5) BSAP, but not OC, was increased relatively more (66%) than the bone formation rate (BFR). Consequently, BSAP is more sensitive to the effects of menopause than OC, but OC is more sensitive to the effects of ethnicity than BSAP. (6) There were highly significant differences between the three subdivisions of the endosteal envelope for every non-cell-related variable. All Class 1 formation variables were highest on the endocortical surface, but the magnitude and pattern of the differences otherwise was inconsistent between variables. The contributions of the different subdivisions to the total bone formation rate were cancellous 54%, endocortical 13%, and intracortical 33%. (7) The previously reported changes in bone surface location, together with the presently reported changes in activation frequency and wall thickness indicated that there was no significant effect of age/menopause on erosion depth on the cancellous and intracortical surfaces but a large increase in erosion depth on the endocortical surface. (8) The increase in bone turnover that results from hormonal changes is most likely in the stochastic rather than in the directed component because it serves no purpose but has harmful effects on skeletal integrity.

Effects of ethnicity and age or menopause on osteoblast function, bone mineralization, and osteoid accumulation in iliac bone.

We measured histologic indices of osteoblast function, bone mineralization, and osteoid accumulation separately on the cancellous, endocortical, and intracortical subdivisions of the endosteal envelope and on the combined total surface in transiliac biopsies obtained after double tetracycline labeling in 142 healthy women, aged 20-74 years, 34 who were black (19 pre- and 15 postmenopausal) and 108 white (42 pre- and 66 postmenopausal). The data were subjected to two-way analysis of variance of the four groups defined by age/menopause and ethnicity. Also, linear regressions of selected variables on age and between functionally related but independently measured variables were examined. None of the interaction terms was significant, and none of the regression slopes on age differed between blacks and whites, indicating that, as for the previously reported structural and remodeling indices, the effects of ethnicity and of age/menopause are independent. Accordingly, the data were analyzed separately for the effects of ethnicity (pre- and postmenopausal combined) and age/menopause (blacks and whites combined). The analyses led to the following conclusions (1) Osteoid surface and volume were higher and adjusted apposition rate and osteoid mineralization rate lower in postmenopausal than in premenopausal subjects, but none of the indices of osteoid accumulation differed between blacks and whites. (2) Each index of osteoid accumulation was significantly correlated with its primary independently measured kinetic determinant (osteoid thickness with adjusted apposition rate, osteoid surface/bone surface with activation frequency, and osteoid volume/bone volume with bone formation rate/bone volume). None of the regression parameters differed significantly between blacks and whites. (3) The ratio of mineralizing surface to osteoid surface (MS/OS) was substantially lower in all demographic groups than could be accounted for by the later onset of mineralization than of matrix apposition at individual bone forming sites. (4) The low values for MS/OS can be explained by terminal mineralization being too slow to trap enough tetracycline molecules to produce detectable fluorescence, and do not require that mineralization be interrupted. (5) MS/OS was about 25% lower in blacks than in whites on all surfaces with corresponding differences in derived indices based on MS/OS, including adjusted apposition rate, mineralization lag time, and formation period. (6) The lower values for MS/OS in blacks are most likely due to slower terminal mineralization. This could not be accounted for by a lower serum level of calcidiol, but is consistent with the reported effect of reduced bone blood flow. (7) All differences in bone cell function between blacks and whites that we have observed could be the result of the ethnic, and presumably genetic, difference in bone accumulation during growth. Higher bone mass would result in less fatigue microdamage, less need for repair by directed bone remodeling, lower bone turnover, lower bone blood flow, and slower terminal mineralization. (8) If this explanation is correct, there are no fundamental differences in the biology of bone remodeling between ethnic groups.

Effect of ethnicity and age or menopause on the structure and geometry of iliac bone.

We measured indices of bone volume (cancellous, cortical) and bone surface (cancellous, endocortical, and intracortical) in intact full-thickness transiliac bone biopsies obtained from 144 healthy women aged 20-74 (35 black and 109 white, 62 premenopausal and 82 postmenopausal). The data were analyzed by two-way analysis of variance of the four groups defined by age/menopause and ethnicity and by linear regression of major variables on age. None of the interaction terms was significant, and none of the regression slopes on age differed between blacks and whites, indicating that the effects of ethnicity and of age/menopause were independent. Accordingly, the data were also analyzed separately for the effects of ethnicity (pre- and postmenopausal combined) and age/menopause (blacks and whites combined). The analyses led to the following conclusions. (1) Blacks have more cancellous and cortical bone than whites in the ilium; the difference was due to thicker trabeculae and thicker cortices with no difference in trabecular number or cortical porosity. (2) The magnitude of the black/white differences was the same throughout the age range covered by the study, indicating differences in peak adult values, not in rates of loss with age. (3) As the result of age/menopause, there were significant reductions in all indices of the amount and structure of bone except for trabecular thickness; the magnitude of the reductions was the same in blacks and whites. (4) Cancellous bone loss was mainly the result of the complete removal of some trabecular elements with increased separation between remaining elements. Cortical bone loss was due to thinning from the endocortical surface with a small but significant contribution from increased cortical porosity, due to an increased number of intracortical canals. These patterns of bone loss were the same in blacks and whites. (5) Although the percentage losses of bone with age/menopause were higher for cancellous than for cortical bone, the absolute amounts of bone lost were about the same for cortical as for cancellous bone. (6) The ratio of surface to tissue volume decreased with age/menopause in cancellous bone but increased in cortical bone; rates of bone loss would change in the same manner if the loss per unit of surface remained constant. (7) The total extent of bone surface in the ilium did not change with age/menopause, so that the surface/volume ratio for the entire bone increased; volumetric bone turnover would increase and bone age decrease if remodeling activity per unit of surface remained constant.