Tumoral Intraductal Neoplasms of the Bile Ducts Comprise Morphologically and Genetically Distinct Entities

CONTEXT.—

Tumoral (grossly visible) intraductal neoplasms of the bile ducts are still being characterized.

OBJECTIVE.—

To investigate their morphologic, immunohistochemical, and molecular features.

DESIGN.—

Forty-one cases were classified as gastric-, intestinal-, pancreatobiliary-type intraductal papillary neoplasm (IPN), intraductal oncocytic papillary neoplasm (IOPN), or intraductal tubulopapillary neoplasm (ITPN) on the basis of histology. All neoplasms were subjected to targeted next-generation sequencing.

RESULTS.—

The mean age at diagnosis was 69 years (42-81 years); male to female ratio was 1.3. Most neoplasms (n = 23, 56%) were extrahepatic/large (mean size, 4.6 cm). The majority (n = 32, 78%) contained high-grade dysplasia, and 68% (n = 28) revealed invasion. All gastric-type IPNs (n = 9) and most ITPNs/IOPNs showed consistent colabeling for CK7/MUC6, which was less common among others (P = .004). Intestinal-type IPNs (n = 5) showed higher rates of CK20 expression than others (P < .001). Overall, the most commonly mutated genes included TP53 and APC, while copy number variants affected ELF3 and CDKN2A/B. All gastric-type IPNs contained an alteration affecting the Wnt signaling pathway; 7 of 9 (78%) showed aberrations in the MAPK pathway. Mutations in APC and KRAS were common in gastric-type IPNs as compared with others (P = .01 for both). SMAD4 was more frequently mutated in intestinal-type IPNs (P = .02). Pancreatobiliary-type IPNs (n = 14) exhibited frequent alterations in tumor suppressor genes including TP53, CDKN2A/B, and ARID2 (P = .04, P = .01 and P = .002, respectively). Of 6 IOPNs analyzed, 3 (50%) revealed ATP1B1-PRKACB fusion. ITPNs (n = 6) showed relatively few recurrent genetic aberrations. Follow-up information was available for 38 patients (median, 58.5 months). The ratio of disease-related deaths was higher for the cases with invasion (56% versus 10%).

CONCLUSIONS.—

Tumoral intraductal neoplasms of the bile ducts, similar to their counterparts in the pancreas, are morphologically and genetically heterogeneous.

Co-Presentation of Lupus Nephritis with Autoimmune Hepatitis

BACKGROUND Systemic lupus erythematosus (SLE) is a multiorgan immunologic disease which commonly results in systemic manifestations by involving joints, kidneys, skin, heart, hematologic cell lines, pulmonary and central nervous systems. The hepatic involvement of lupus is relatively less common, which creates diagnostic challenges, as the clinical presentations of lupus hepatitis and autoimmune hepatitis (AIH) are similar. CASE REPORT A 51-year-old woman presented for multiple joint pain that began 2 years ago. Her work-up, including kidney biopsy, was consistent with a diagnosis of class V lupus nephritis. Subsequently, within a few months, she was admitted with acute elevation of liver enzymes and high immunoglobulin IgG level, and a liver biopsy demonstrated impressive interface hepatitis with many plasma cells and lymphocytes, suggestive of chronic hepatitis with high histological activity. This case illustrates the co-presentation of lupus nephritis and AIH, which is a rare association. The patient was managed with a tapering dose of prednisone, hydroxychloroquine initially, and later with mycophenolate mofetil, with complete resolution of liver enzyme abnormalities by 4-month follow-up. CONCLUSIONS Lupus hepatitis is hepatic involvement of SLE, which should be distinguished from AIH. Accurate diagnosis is important, as management and prognosis of these immunologic conditions can differ. Although both entities share clinical and biochemical markers, the presence of anti-ribosomal P antibodies and liver histology features of predominant lymphoid infiltrates with lobular inflammation favor lupus hepatitis. A multidisciplinary approach involving rheumatologists, hepatologists, and pathologists can improve disease outcomes by properly differentiating the 2 entities and guiding the selection of appropriate immunosuppressive therapy.

EUS-guided versus percutaneous liver biopsy: A prospective randomized clinical trial

Background and Objectives

Prospective studies comparing EUS-guided liver biopsy (EUS-LB) to percutaneous LB (PC-LB) are scarce. We compared the efficacy and safety of EUS-LB with those of PC-LB in a prospective randomized clinical trial.

Methods

Between 2020 and 2021, patients were enrolled and randomized (1:1 ratio). The primary outcome was defined as the proportion of patients with ≥11 complete portal tracts (CPTs). The sample size (n = 80) was calculated based on the assumption that 60% of those in the EUS-LB and 90% of those in the PC-LB group will have LB with ≥11 CPTs. The secondary outcomes included proportion of patients in whom a diagnosis was established, number of CPTs, pain severity (Numeric Rating Scale-Pain Intensity), duration of hospital stay, and adverse events.

Results

Eighty patients were enrolled (median age, 53 years); 67.5% were female. Sixty percent of those in the EUS-LB and 75.0% of those in the PC-LB group met the primary outcome (P = 0.232). The median number of CPTs was higher in the PC-LB (17 vs 13; P = 0.031). The proportion of patients in whom a diagnosis was established was similar between the groups (92.5% [EUS-LB] vs 95.0% [PC-LB]; P = 1.0). Patients in the EUS-LB group had less pain severity (median Numeric Rating Scale-Pain Intensity, 2.0 vs 3.0; P = 0.003) and shorter hospital stay (2.0 vs 4.0 hours; P < 0.0001) compared with the PC-LB group. No patient experienced a serious adverse event.

Conclusions

EUS-guided liver biopsy was safe, effective, better tolerated, and associated with a shorter hospital stay.

Histologic diagnosis of a case of anal duct carcinoma with cytological correlation and differential diagnoses

Anal duct carcinoma is an uncommon malignancy of the glands of the anal duct. This entity poses a diagnostic challenge, both clinically and histologically. This article describes histopathologic findings in a case of anal duct carcinoma, including the initial diagnosis on biopsy and subsequent cytology specimens. Additionally, differential diagnoses of this neoplasm are discussed. With a high index of suspicion, and attention to histological and immunohistochemical features, anal duct carcinoma can be accurately diagnosed both on biopsy and on cytology.

The efficacy and safety of endoscopic ultrasound-guided liver biopsy versus percutaneous liver biopsy in patients with chronic liver disease: a retrospective single-center study

BACKGROUND AND AIMS

There is limited literature on endoscopic ultrasound-guided liver biopsy (EUS-LB), a new method of obtaining liver biopsy (LB).

METHODS

We conducted a retrospective study of the efficacy and safety of EUS-LB compared to percutaneous liver biopsy (PC-LB) in patients with chronic liver disease at our center between January 2018 and August 2019.

RESULTS

Thirty patients underwent EUS-LB and 60 patients underwent PC-LB were identified (median follow-up post-LB was 8 days; interquartile range (IQR), 3-5 days). The median number of portal tracts was significantly higher in the PC-LB group (13 vs. 5; P < 0.0001). A histologic diagnosis was established in 93% of the EUS-LB group, compared to 100% in the PC-LB group (P = 0.841). Patients in EUS-LB group had significantly shorter hospital stay (median time of hospital stay was 3 vs. 4.2 h in the EUS-LB vs. PC-LB group, respectively; P = 0.004) and reported less pain compared to PC-LB group (median pain score was 0 vs. 3.5; P = 0.0009). EUS-LB were performed using a 19-gauge (n = 27) or 22-gauge (n = 3); there was a tendency towards higher number of portal tracts in the 22- vs. the 19-gauge needle group (6 vs. 5; P = 0.501). No patient in either group had significant adverse events such as bleeding or death.

CONCLUSION

EUS-LB is safe and is associated with less pain, shorter hospital stay, and high diagnostic yield (93%) compared to PC-LB. Randomized trials are needed to standardize the utility of EUS-LB.

Community gastroenterologists can learn diminutive colon polyp histology characterization with narrow band imaging by a computer-based teaching module

BACKGROUND AND AIM

The aim of the present study was to evaluate the impact of a computer-based teaching module on the performance of community gastroenterologists for characterization of diminutive polyps (≤5 mm) using narrow band imaging video clips.

METHODS

Eighty videos were distributed in pre- and post-test DVD along with a 20-min audiovisual teaching presentation detailing endoscopic features differentiating adenomas from hyperplastic polyps using narrow band imaging. Each participant first reviewed pretest video clips and entered their responses for polyp histology and their confidence in diagnosis: high: ≥90% or low: <90%. Following this, they reviewed the teaching module and assessed the post-test videos. Performance characteristics were calculated for pre- and post-test videos by comparing predicted histology with actual histology. Fisher's exact test was used for analysis and the kappa statistic was calculated for interobserver agreement.

RESULTS

Fifteen gastroenterologists in community practice completed the study. Sensitivity, specificity, accuracy and negative predictive value in characterization of polyp histology improved significantly post-test compared to pretest. In post-test, accuracy was 92% for high-confidence diagnoses and the proportion of these increased with training from 46% (pretest) to 64% (post-test); P < 0.001. Interobserver agreement for diagnosis improved from fair (kappa = 0.23) in pretest to moderate (kappa = 0.56) in post-test.

CONCLUSIONS

A teaching module using video clips can be used to teach community gastroenterologists polyp histology characterization by narrow band imaging. Whether this translates into real-time high accuracy in polyp detection needs to be further evaluated.

Impact of a computer-based teaching module on characterization of diminutive colon polyps by using narrow-band imaging by non-experts in academic and community practice: a video-based study

BACKGROUND

Experts can accurately characterize the histology of diminutive polyps with narrow-band imaging (NBI). There are limited data on the performance of non-experts.

OBJECTIVE

To assess the impact of a computer-based teaching module on the accuracy of predicting polyp histology with NBI by non-experts (in academics and community practice) by using video clips.

DESIGN

Prospective, observational study.

SETTING

Academic and community practice.

PARTICIPANTS

A total of 15 gastroenterologists participated-5 experts in NBI, 5 non-experts in academic practice, and 5 non-experts in community practice.

INTERVENTION

Participants reviewed a 20-minute, computer-based teaching module outlining the different NBI features for hyperplastic and adenomatous polyps.

MAIN OUTCOME MEASUREMENTS

Performance characteristics in characterizing the histology of diminutive polyps with NBI by using short video clips before (pretest) and after (posttest) reviewing the teaching module.

RESULTS

Non-experts in academic practice showed a significant improvement in the sensitivity (54% vs 79%; P < .001), accuracy (64% vs 81%; P < .001), and proportion of high-confidence diagnoses (49% vs 69%; P < .001) in the posttest. Non-experts in community practice had significantly higher sensitivity (58% vs 75%; P = .004), specificity (76% vs 90%; P = .04), accuracy (64% vs 81%; P < .001), and proportion of high-confidence diagnoses (49% vs 72%; P < .001) in the posttest. Performance of experts in NBI was significantly better than non-experts in both academic and community practice.

LIMITATIONS

Selection bias in selecting good quality videos. Performance not assessed during live colonoscopy.

CONCLUSION

Academic and community gastroenterologists without prior experience in NBI can achieve significant improvements in characterizing diminutive polyp histology after a brief computer-based training. The durability of these results and applicability in everyday practice are uncertain.

Effect of gender and geographic location on the expression of primary hyperparathyroidism

BACKGROUND

The effect of gender on the expression of primary hyperparathyroidism (PHPT) is not well characterized.

AIM

We therefore evaluated two Caucasian populations (US and Italian) of men and women with PHPT, matched for age and body mass index (BMI), in a cross-sectional retrospective observational study.

METHODS

We studied 74 US (23 men) and 126 Italian (42 men) patients evaluating main biochemical indices of the disease and bone mineral density (BMD) at the spine and proximal femur.

RESULTS

Mean serum calcium levels were higher both in Italian men compared to women (11.7 ± 1.22 mg/dl and 11.1 ± 0.83, p<0.01) and in Italian compared to US patients (11.3 ± 1.01 and 10.8 ± 0.58, p<0.001), with similar results for the serum ionized calcium. Mean serum PTH levels were not different either between the genders or between the countries. After controlling for BMI, the mean BMD at both the femoral neck and total hip in females US patients was significantly higher compared with Italian female patients.

CONCLUSION

Despite similar levels of circulating PTH, Italian patients have more pronounced effects of the disease as assessed by serum calcium and a more significant cortical involvement in women as assessed by BMD.

Higher adenoma detection rates with cap-assisted colonoscopy: a randomised controlled trial

OBJECTIVE

Cap-assisted colonoscopy (CAC) uses a small plastic transparent cap attached to the tip of the colonoscope that can depress and flatten colonic folds and thus improve visualisation of their proximal aspects. The aim of this study was to compare CAC with standard colonoscopy (SC; high-definition white light) for adenoma detection rates.

DESIGN

This is a prospective randomised controlled trial.

SETTING

The study was performed in a tertiary-care Veterans Affairs Medical Center in the USA.

PATIENTS

Subjects undergoing screening or surveillance colonoscopy were enrolled.

INTERVENTIONS

Subjects were randomised to undergo either CAC or SC.

MAIN OUTCOME MEASURES

The outcome measures were the proportion of subjects with at least one adenoma, the number of adenomas detected per subject, insertion time, caecal intubation rates and complications.

RESULTS

420 subjects were enrolled and included in the study (210 in each group). The proportion of subjects with at least one adenoma was higher with CAC compared to SC (69% vs 56%, p=0.009). CAC also detected a higher number of adenomas per subject (2.3 vs 1.4, p<0.001). The caecal intubation time was shorter with CAC (3.29 min vs 3.98 min, p<0.001). The caecal intubation rates were similar in the two groups (99% vs 98%, p=0.37). There were no complications associated with CAC or SC.

CONCLUSIONS

CAC detected a 13% higher number of subjects with at least one adenoma and 59% higher adenomas per subject. CAC is a safe, effective and practical means to improve adenoma detection rates.

CLINICAL TRIAL REGISTRATION

NCT 01211132.

Changes in serum leptin and adiponectin concentrations and insulin resistance after curative parathyroidectomy in moderate to severe primary hyperparathyroidism

INTRODUCTION

Primary hyperparathyroidism (PHPT) is considered a state of insulin resistance. However, it is unclear whether the state of insulin resistance and adverse levels of adipocytokines are reversed in PHPT patients who have undergone curative parathyroidectomy.

METHODS

Ten consecutive patients with PHPT were studied at baseline and three months after curative parathyroid surgery in this prospective interventional study. Fasting blood calcium, intact parathyroid hormone (PTH), glucose, insulin, adiponectin and leptin concentrations were measured. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA- IR) and insulin sensitivity, by the quantitative insulin sensitivity check index (QUICKI).

RESULTS

Four out of the ten patients were male. The mean age of the patients was 32.40 +/- 11.42 years, and the mean body mass index was 23.70 +/- 5.19 kg/m2. The HOMA-IR value was found to be higher, while the QUICKI value was significantly lower before surgery in patients with PHPT compared to the published reference ranges. Serum leptin concentrations were higher in patients with PHPT than in normal healthy individuals; however, there was no difference in the adiponectin concentrations. There was no statistical difference in the mean values of fasting plasma glucose, plasma insulin, leptin, adiponectin, as well as the HOMA-IR and QUICKI estimates three months postoperatively, as compared to the preoperative measures.

CONCLUSION

Peripheral insulin resistance/sensitivity and the concentrations of leptin and adiponectin did not change three months after curative parathyroidectomy.

Application of dolochar in the removal of cadmium and hexavalent chromium ions from aqueous solutions

Dolochar, a waste material generated in sponge iron industry, is processed and put to test as an adsorbent for removal of Cd(II) and Cr(VI) ions from aqueous solutions. The dolochar samples were characterised to determine the different phases and their distribution by reflection microscopy. The analysis indicated that the sample consists of metallic iron, fused carbon, and Ca-Mg bearing phases (Ca-Mg-silicate-oxide) along with lots of voids and pores. The fixed carbon (FC) content of the material is 13.8% with a Langmuir surface area of 81.6m(2)/g and micropore area of 34.1m(2)/g. Batch adsorption experiments have been conducted to study the sorption behaviour of Cd(II) and Cr(VI) ions on dolochar as a function of particle size, contact time, adsorbent dosages, pH and temperature. It is observed that higher pH and temperature enhances sorption of Cd(II) ions. In contrast, the adsorption for Cr(VI) is found to be better in acidic pH in comparison to alkaline media. The equilibrium adsorption isotherm data are tested by applying both Langmuir and Freundlich isotherm models. It is observed that Langmuir isotherm model fitted better compared to the Freundlich model indicating monolayer adsorption. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° indicate the effectiveness of dolochar to remove Cd(II) and Cr(VI) ions from aqueous solution. The kinetics of adsorption is found to better fit to pseudo second order reaction.

Unusual mid-shaft fractures during long-term bisphosphonate therapy

BACKGROUND

Bisphosphonates are the most commonly prescribed medications for the treatment of osteoporosis. Although existing evidence supports a good safety profile, there is concern that chronic administration of these agents could result in severe suppression of bone turnover with increased risk of nonvertebral fractures.

OBJECTIVE

The objective of this study was to report the clinical presentation, selected bone histomorphometry and X-ray images of patients who developed mid-shaft long bone fractures during bisphosphonate therapy, six of whom had bone biopsy for histomorphometery.

RESULTS

Of the 13 patients who sustained atraumatic mid-shaft fractures, 10 were on alendronate and three were on risedronate therapy before the fractures. In addition to bisphosphonates, three patients were on oestrogen and two on tamoxifen concomitantly. Four patients with glucocorticoid-induced osteoporosis were on alendronate for 3-11 years along with glucocorticoid therapy. Bone histomorphometry showed severe suppression of bone turnover in five patients and low bone turnover in one patient.

CONCLUSION

Long-term bisphosphonate therapy may increase the risk of unusual long bone mid-shaft fractures. This is probably due to prolonged suppression of bone turnover, which could lead to accumulation of microdamage and development of hypermineralized bone. At present, the scope of this complication in the larger context of patients receiving bisphosphonate therapy remains unknown, but appears to be small.

Endovascular stenting for native coarctation in older children and adolescents using adult self-expanding (Nitinol) iliac stents

BACKGROUND

The role of balloon-expandable stents for native coarctation has been proven in several small studies. Use of Nitinol-made self-expanding stents in such situations is reported in adults in only a few cases. For the last 5 years we used self expanding nitinol stents (primarily recommended for iliac angioplasty in adults in this condition in older children.

METHODS

There were 32 patients in total (24 males; mean age 10.2 +/- 1.43 years; youngest 6-years-old). Successful procedure is defined as reduction of gradient to less than 20 mmHg or increase in the ratio of the diameter of the coarctation area to the diameter of the descending aorta to at least 0.8. Bard luminexx vascular stents were used in all cases.

RESULTS

In 32 patients 32 stents were used with overall success rate of 31/32 (96.8%). The peak systolic pressure gradient (mean (SD) decreased from 48.8 (23.5) to 2.2 (1.86) mm Hg (p<0.05). The diameter of the stenotic lesion increased from 5.6 (1.6) mm to 12.5 (2.6) (p<0.05). In one patient 2 stents were used because the first stent migrated downwards leaving the lesion partially uncovered. Nitinol stents were easier to deploy and conformed well to aortic walls. In the only unsuccessful case, the lesion was 12 mm long, tubular and did not yield even at 16 atm pressure. This case was taken up for elective surgery at a later date. There were no deaths or cerebrovascular events. Two cases had femoral artery access related problems (hematoma-1, loss of pulse-1). Twenty five of the 31 successful cases were on regular follow-up. On mean follow-up of 1.25 years one had re-coarctation and successful balloon dilation was done. Another case with re-coarctation and persistent hypertension underwent elective surgical repair. There were no aortic aneurysms in any case.

CONCLUSIONS

Stent implantation using this readily available low cost adult peripheral self-expanding stents gave gratifying, acute and early term results in treatment of coarctation of aorta in older children and adolescents. Ease of deployment, conforming to the aortic anatomy and low cost appear the main advantages of these stents.

Cloning of rhesus monkey LILRs*

Leukocyte Ig-like receptors (LILRs) are a family of receptors that have inhibitory and activating functions and widely expressed by lymphoid and myeloid cells. Here we report the identification of the rhesus monkey LILRs by screening of rhesus spleen and decidua cDNA libraries and RT-PCR cloning. We obtained eight different full-length clones with structural and functional diversity similar to human LILRs, including LILRs with immunoreceptor tyrosine-based inhibitory motifs, LILRs with truncated cytoplasmic tails containing positively charged arginine residues in the transmembrane domain, and putative soluble receptors lacking transmembrane or cytoplasmic domains. Characterization of rhesus LILRs will facilitate use of this non-human primate model for the study of the functional role(s) of LILRs, including immune regulation through interaction with non-classical MHC class I molecules.

Larva currensin a case of Organophosphorous poisoning

A 20-year-old healthy farmer consumed organophosphorous poison. On third day he developed diarrhoea and on fourth day linear serpiginous ulcers appeared on both buttocks. Clinically lesions were considered as decubitus ulcers. By stool examination and other laboratory investigations it was diagnosed as cutaneous larva currens due to Strongyloides stercoralis in a case of organophosphorus poisoning. Patient responded very well to a course of albendazole.

The mineralization index--a new approach to the histomorphometric appraisal of osteomalacia

The histomorphometric diagnosis of osteomalacia depends on the conjunction of two or three independent criteria but for several reasons, both clinical and pathophysiologic, it would be useful to have a single index of severity. Accordingly, using an extensive library of normal values in 143 healthy women, we constructed the mineralization index (MI), defined as [osteoid thickness (O.Th) (microm) + osteoid volume/bone volume (OV/BV) (%)] x 1.15 - osteoid mineralization rate (%/day) - [bone formation rate/bone surface (BFR/BS) (microm3/microm2/year) x 0.15]. MI was normally distributed with mean 8.0, SD 3.3, and range 0-15 (arbitrary units); it was unaffected by race, menopausal status, age or bone turnover, and was slightly lower in osteoporotic patients with nontraumatic vertebral fracture than in healthy white postmenopausal women (6.83 vs. 7.95). In hypovitaminosis D osteopathy (HVO) stage I, MI was normal in 18/26 cases (70%; HVOia), demonstrating more rigorously than before that osteoid accumulation is initially due entirely to secondary hyperparathyroidism and increased bone turnover. In the remaining 30% (HVOib), MI was increased, indicating the onset of impaired mineralization while bone formation was still increased and before the appearance of osteomalacia. In secondary hyperparathyroidism due to renal bone disease, 10/20 cases (50%) had normal MI and higher BFR than in HVOia (93 vs. 32), and there was a significant inverse correlation between MI and BFR. In patients with osteomalacia according to current criteria, MI ranged from 29.2 to 166.5; an MI of 30 had high sensitivity and specificity for the diagnosis of osteomalacia. Including all patients with HVO, there was a significant (P < 0.001) inverse correlation between MI and calcium x phosphate product, but the unexplained variance of >70% suggests that vitamin D deficiency impairs mineralization by multiple mechanisms. We conclude that the MI clarifies the early effects of vitamin D deficiency on bone and the relationship between different components of renal bone disease simplifies the histologic diagnosis of osteomalacia and may contribute to its management, and explicates the mechanisms of mineralization.

Randomized trial of parathyroidectomy in mild, asymptomatic primary hyperparathyroidism as measured by the SF-36 health survey

Background

Management of patients with asymptomatic primary hyperparathyroidism (HPT) remains controversial despite a National Institutes of Health consensus statement on this issue. As part of the above statement, a randomized clinical trial was recommended since none exist to address this issue.

Methods

Informed consent was obtained from 53 asymptomatic patients with confirmed primary HPT who agreed to participate in this randomized clinical trial of parathyroidectomy versus observation. Upon entry to the study and 24 months later the patients completed the SF-36 health survey which is an instrument that measures nine different levels of function. Scores were tabulated and the difference over 24 months between operated and non-operated patients was compared with Student's t test.

Results

Fifty-three patients (42 women and 11 men) with asymptomatic, mild primary HPT (serum calcium 10·1–11·5 mg dl−1) who agreed to participate were randomized into either a surgical group or an observation group. Mean serum calcium for these patients was 10·3 mg dl−1. The only demographic difference between the groups was age; the operated group was older (66·7 versus 62·6 years; P &lt; 0·03). Scores on three of the nine domains (health perception, emotional problems and social functioning) on the SF-36 were significantly different (P &lt; 0·05), all favouring the operated group.

Conclusion

Improved function, as measured by the SF-36 health assessment tool, is seen after parathyroidectomy compared with non-operated patients. This work supports surgical management of mild primary HPT at the time of diagnosis since many patients have reversible non-classical symptoms of the disease.

Relationships between osteocyte density and bone formation rate in human cancellous bone

Iliac cancellous osteocyte density decreases with age in deep bone but not in superficial bone, most likely because of remodeling. It has been suggested that osteocytes can inhibit bone remodeling. Accordingly, we examined the relationship between osteocyte density and bone formation rate in 92 healthy women. In superficial bone (<25 microm from the surface), we found a weak but significant (p < 0.03) inverse correlation between BFR/BS and Ot. N/B.Ar that was unaffected by menopause and independent of age. A weaker positive relationship with empty lacunar density improved significance. The data appear to suggest a negative feedback loop, but osteocytes explain only 10% of the variance in BFR/BS, and 97% of the variance in osteocyte density is explained by total lacunar density. This measure of initial osteocyte density during bone formation has a high coefficient of variation (20%) indicating large individual differences. We conclude that: (1) our data support the proposal that osteocytes can inhibit bone remodeling; (2) osteocyte density in superficial bone depends mainly on initial osteocyte density during bone formation and is maintained but not regulated by bone remodeling; and (3) the inverse relationship between BFR/BS and osteocyte density may reflect the homeostatic need to maintain calcium exchangeability in the lining cell-osteocyte syncytium.

Age and distance from the surface but not menopause reduce osteocyte density in human cancellous bone

Previous studies of osteocyte density in human cancellous bone have relied mainly on autopsy samples and have demonstrated an age-related decline in men, but there are insufficient data in women. Using previously obtained transiliac bone biopsies from 94 healthy white women, aged 20-73 years, 38 premenopausal and 56 postmenopausal, we measured osteocytes and lacunae in ten randomly selected areas using 5-microm-thick sections stained with Goldner trichrome. For each subject, the number of osteocytes (Ot.N/B.Ar), empty lacunae (EL.N/B.Ar), and total lacunae (Tt.L.N/B.Ar) per bone area, and the proportion of occupied lacunae (Ot.N/Tt.L.N), were calculated. In 92 cases the measurements were made separately in superficial bone (<25 microm from the surface) and in deep bone (>45 microm from the surface). Mean values and differences between extreme values (DEV) for each variable were computed from the ten measured areas. In addition, confocal microscopic examination was performed on 100 microm sections. We found that Ot.N/B.Ar, Tt.L.N/B.Ar, and Ot.N/Tt.L.N decreased, but EL.N/B.Ar increased significantly with age (p < 0.001). The rates of decline were most rapid initially, falling exponentially with increasing age; the linear regressions for all four variables were significant in premenopausal, but not postmenopausal, women. At all ages, there were significantly more osteocytes in superficial than in deep bone; there was no significant decline with age in superficial bone, but a steeper exponential decline in deep bone than in whole trabeculae. DEV did not change with age for any variable. Confocal images revealed that the morphology of the osteocyte network was heterogeneous in different regions and trabeculae. The trabeculae with lower osteocyte density contained acellular areas, especially in interstitial bone. We conclude: (1) osteocyte density declines with age in women as it does in men; (2) the decline occurs exclusively in deep bone, not in superficial bone, suggesting that it is the age of the bone rather than the age of the subject that is important; (3) the rate of age-related decline falls exponentially with age and is not significant in postmenopausal women alone; (4) except for the differences between superficial and deep bone, the pattern of osteocyte distribution within and between trabeculae was not affected by age or menopause; and (5) the data raise the possibility that one function of remodeling in iliac cancellous bone is to maintain osteocyte viability.

Huntingtin interacting protein 1 Is a clathrin coat binding protein required for differentiation of late spermatogenic progenitors

Huntingtin-interacting protein 1 (HIP1) interacts with huntingtin, the protein whose gene is mutated in Huntington's disease. In addition, a fusion between HIP1 and platelet-derived growth factor beta receptor causes chronic myelomonocytic leukemia. The HIP1 proteins, including HIP1 and HIP1-related (HIP1r), have an N-terminal polyphosphoinositide-interacting epsin N-terminal homology, domain, which is found in proteins involved in clathrin-mediated endocytosis. HIP1 and HIP1r also share a central leucine zipper and an actin binding TALIN homology domain. Here we show that HIP1, like HIP1r, colocalizes with clathrin coat components. We also show that HIP1 physically associates with clathrin and AP-2, the major components of the clathrin coat. To further understand the putative biological role(s) of HIP1, we have generated a targeted deletion of murine HIP1. HIP1(-/-) mice developed into adulthood, did not develop overt neurologic symptoms in the first year of life, and had normal peripheral blood counts. However, HIP1-deficient mice exhibited testicular degeneration with increased apoptosis of postmeiotic spermatids. Postmeiotic spermatids are the only cells of the seminiferous tubules that express HIP1. These findings indicate that HIP1 is required for differentiation, proliferation, and/or survival of spermatogenic progenitors. The association of HIP1 with clathrin coats and the requirement of HIP1 for progenitor survival suggest a role for HIP1 in the regulation of endocytosis.

Sustained-release sodium fluoride in the treatment of the elderly with established osteoporosis

BACKGROUND

We ascertained the safety and efficacy of fluoride in augmenting spinal bone mass and reducing spinal fractures in older women with established osteoporosis. We compared a combination of sustained-release sodium fluoride, calcium citrate, and cholecalciferol (SR-NaF group) with calcium and cholecalciferol alone (control group).

METHODS

Eighty-five ambulatory women aged 65 years or older with 1 or more nontraumatic vertebral compression fractures were enrolled in a 42-month randomized, double-blind, placebo-controlled trial. Primary outcome measures were vertebral fracture rate, bone mass, and safety.

RESULTS

The vertebral fracture rate determined by means of computer assistance in the SR-NaF group was significantly lower than that in the control group (relative risk [RR], 0.32; 95% confidence interval [CI], 0.14-0.73; P =.007). Results of visual adjudicated inspection also confirmed a significant reduction in fracture rate (RR, 0.40; 95% CI, 0.17-0.95; P =.04). Bone mineral density in L2 through L4 increased significantly from baseline in the SR-NaF group by 5.4% (95% CI, 2.7%-8.2%; P<.001), and by 3.2% in the control group (95% CI, 0.8%-5.6%; P =.01). The between-group differences in bone mineral density were not significant. The femoral neck and total hip bone mineral density remained stable in the SR-NaF group and was not significantly different from that of the control group. There were no significant differences in adverse effects between groups.

CONCLUSION

The SR-NaF group significantly decreased the risk for vertebral fractures and increased spinal bone mass without reducing bone mass at the femoral neck and total hip.

Tissue specific metabolism of 1alpha,25-dihydroxy-20-epi-vitamin D3 into new metabolites with significant biological activity: studies in rat osteosarcoma cells (UMR 106 and ROS 17/2.8)

In a recent study, we investigated the metabolism of 1alpha,25-dihydroxy-20-epi-vitamin D3 (1alpha,25(OH)2-20-epi-D3), a potent synthetic vitamin D3 analog in the isolated perfused rat kidney and proposed that the enhanced biological activity of 1alpha,25(OH)2-20-epi-D3 is in part due to its metabolism into stable bioactive intermediary metabolites derived via the C-24 oxidation pathway (Siu-Caldera et al. [1999] J. Steroid. Biochem. Mol. Biol. 71:111-121). It is now well established that 1alpha,25(OH)2D3 and its analogs are metabolized in target tissues not only via the C-24 oxidation pathway but also via the C-3 epimerization pathway. As the perfused rat kidney does not express the C-3 epimerization pathway, we could not identify other possible bioactive metabolites of 1alpha,25(OH)2-20-epi-D3 such as 1alpha,25(OH)2-20-epi-3-epi-D3, derived via the C-3 epimerization pathway. Therefore, we studied the metabolism of 1alpha,25(OH)2-20-epi-D3 in rat osteosarcoma cells (UMR 106) which express both the C-24 oxidation and the C-3 epimerization pathways. Our results indicate that 1alpha,25(OH)2-20-epi-D3 is metabolized in UMR 106 cells into several metabolites which included not only the previously known metabolites of the C-24 oxidation pathway but also three new metabolites which were labeled as metabolites X, Y1, and Y2. Metabolite X was unequivocally identified as 1alpha,25(OH)2-20-epi-3-epi-D3. Even though definite structure identification of the metabolites, Y1 and Y2 was not achieved in our present study, we determined that the metabolite Y1 is produced from 1alpha,25(OH)2-20-epi-D3 and the metabolite Y2 is produced from 1alpha,25(OH)2-20-epi-3-epi-D3. We also noted the production of both 1alpha,25(OH)2-20-epi-3-epi-D3 and the two metabolites Y1 and Y2 in different rat osteosarcoma cells (ROS 17/2.8) which express only the C-3 epimerization pathway but not the C-24 oxidation pathway. Furthermore, we investigated the metabolism of 1alpha,25(OH)2-20-epi-D3 in the isolated perfused rat kidney in an earlier study. The results of this study indicated that the rat kidney unlike rat osteosarcoma cells did not produce either 1alpha,25(OH)2-20-epi-3-epi-D3 or the metabolites Y1 and Y2. Thus, it appears that the metabolites Y1 and Y2, like 1alpha,25(OH)2-20-epi-3-epi-D3, are produced only in specific tissues. Preliminary biological activity of each new metabolite is assessed by measuring its ability to generate VDR-mediated gene transcription. 1alpha,25(OH)2-20-epi-3-epi-D3 was found to be almost equipotent to 1alpha,25(OH)2-20-epi-D3 while the metabolites, Y1 and Y2 were found to be less active. The metabolite Y1 when compared to the metabolite Y2 has higher biological activity and its potency is almost equal to 1alpha,25(OH)2D3. In summary, we report for the first time tissue specific metabolism of 1alpha,25(OH)2-20-epi-D3 into several bioactive metabolites which are derived not only via the previously established C-24 oxidation and C-3 epimerization pathways but also via a new pathway. (c) 2001 Wiley-Liss, Inc.

Vasculogenic impotence. Arterial and venous surgery

Arterial revascularization and venous ligation procedures have been introduced within the past 2 decades. Each procedure has in common with the other the fact that initial applications of the operations were widespread among the population of men with vasculogenic erectile dysfunction. In each case, disappointing long-term results led to more limited use of surgery targeting specific groups that clearly would benefit from the procedures. The wider application of these procedures in vasculogenic erectile dysfunction is not supported by the available results. The Clinical Guidelines Panel of the American Urological Association supported this view in 1996 after a meta-analysis of literature reports and declared that venous and arterial surgery was not justified in routine use, especially in patients with arteriosclerosis. Further studies are likely to refine patient selection but are unlikely to expand the therapeutic use of these procedures.

Vascular endothelial growth factor restores corporeal smooth muscle function in vitro

PURPOSE

The therapeutic use of vasculogenic growth factors has been successfully demonstrated in models of organ ischemia. We determined whether vascular endothelial growth factor (VEGF) would reverse corporeal smooth muscle dysfunction in the hypercholesterolemic rabbit model of erectile dysfunction.

MATERIALS AND METHODS

A total of 36 New Zealand White rabbits were fed a normal (12) or 1% cholesterol (24) diet and treated after 6 weeks with 0.9 mg. VEGF or vehicle. At 6 weeks 24 rabbits received a single intracavernous dose and 12 received a single intravenous bolus of either drug. Ten days after injection corporeal smooth muscle function was analyzed after relaxation to acetylcholine and sodium nitroprusside using isometric tension studies. Corporeal sections were assessed for smooth muscle content with f-actin staining and VEGF expression by immunohistochemical study and enzyme-linked immunosorbent assay.

RESULTS

Endothelium dependent (acetylcholine) and nitric oxide mediated (sodium nitroprusside) smooth muscle relaxation were impaired in cholesterol fed animals (p = 0.021 and 0.003, respectively). Intracavernous VEGF treatment restored sodium nitroprusside mediated relaxation to normal (p = 0.015) and intravenous VEGF restored acetylcholine and sodium nitroprusside mediated relaxation (p = 0.014 and 0.018, respectively). Decreased smooth muscle content was noted in cholesterol fed animals versus normal diet controls (p = 0.008), which was not affected by VEGF treatment (p = 0.450). Corporeal endothelial cell content was increased after intracavernous but not intravenous VEGF treatment (p = 0.001 and 0.385, respectively). VEGF expression was augmented after treatment with recombinant VEGF (p <0.001).

CONCLUSIONS

VEGF administration variably mitigated the impairment of corporeal smooth muscle relaxation in the hypercholesterolemic rabbit model of erectile dysfunction.

The biological activities of 1alpha,25-dihydroxyvitamin D3 and its synthetic analog 1alpha,25-dihydroxy-16-ene-vitamin D3 in normal human osteoblastic cells and human osteosarcoma SaOS-2 cells are modulated by 17-beta estradiol and dependent on stage of differentiation

We compared the effects of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] and its analog, 1alpha,25-dihydroxy-16-ene-vitamin D3 [1alpha,25(OH)2-16-ene-D3], as well as their interactions with 17-beta estradiol (E2) on osteoblastic function in our human normal (HOB) and osteosarcoma SaOS-2 cell models representing two different stages of differentiation, the more differentiated HOB+DEX cells and SaOS+DEX cells, and the corresponding less differentiated HOB-DEX and SaOS-DEX cells. The differential effects of 1alpha,25(OH)2D3 and 1alpha,25(OH)2-16-ene-D3 and the modulation by E2 on ALP activity in HOB-DEX and HOB+DEX cells were small but significant. The most significant effects were seen in SaOS+DEX cells, in which 1alpha,25(OH)2-16-ene-D3 was 100-fold more potent than 1alpha,25(OH)2D3, the maximal enhancement being exerted at 0.1 nM and 10 nM, respectively. E2 enhanced the stimulatory effects of both compounds, with ALP being increased 2-fold at 0.1 nM (p<0.001). Osteocalcin (OC) production in HOB-DEX cells was stimulated 1.3 to 1.4-fold by 1alpha,25(OH)2D3 and 1alpha,25(OH)2-16-ene-D3 at a concentration of 0.01 nM, with E2 inhibiting the effect of 1alpha,25(OH)2-16-ene-D3. In SaOS-DEX and SaOS+DEX cells, 1alpha,25(OH)2D3 and 1alpha,25(OH)2-16-ene-D3 stimulated OC production 1.6-fold at 0.1 nM with E2 slightly enhancing the effect of 1alpha,25(OH)2D3. Western blot analysis of 1alpha,25(OH)2D3 receptor (VDR) levels showed that in SaOS+DEX cells, the effect of 1alpha,25(OH)2D3 was larger than that of 1alpha,25(OH)2-16-ene-D3. These results show that 1alpha,25(OH)2-16-ene-D3 is biologically active in human osteoblasts.

Metabolism of 1alpha,25-dihydroxyvitamin D(3) in human promyelocytic leukemia (HL-60) cells: in vitro biological activities of the natural metabolites of 1alpha,25-dihydroxyvitamin D(3) produced in HL-60 cells

The secosteroid hormone, 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], induces differentiation of the human promyelocytic leukemia (HL-60) cells into monocytes/macrophages. At present, the metabolic pathways of 1alpha,25(OH)(2)D(3) and the biologic activity of its various natural intermediary metabolites in HL-60 cells are not fully understood. 1alpha,25(OH)(2)D(3) is metabolized in its target tissues via modifications of both the side chain and the A-ring. The C-24 oxidation pathway, the main side chain modification pathway initiated by hydroxylation at C-24 leads to the formation of the end product, calcitroic acid. The C-23 and C-26 oxidation pathways, the minor side chain modification pathways initiated by hydroxylations at C-23 and C-26 respectively together lead to the formation of the end product, 1alpha,25(OH)(2)D(3)-lactone. The C-3 epimerization pathway, the newly discovered A-ring modification pathway is initiated by epimerization of the hydroxyl group at C-3 to form 1alpha,25-dihydroxy-3-epi-vitamin-D(3). We performed the present study first to examine in detail the metabolism of 1alpha,25(OH)(2)D(3) in HL-60 cells and then to assess the ability of the various natural intermediary metabolites of 1alpha,25(OH)(2)D(3) in inducing differentiation and in inhibiting clonal growth of HL-60 cells. We incubated HL-60 cells with [1beta-(3)H] 1alpha,25(OH)(2)D(3) and demonstrated that these cells metabolize 1alpha,25(OH)(2)D(3) mainly via the C-24 oxidation pathway and to a lesser extent via the C-23 oxidation pathway, but not via the C-3-epimerization pathway. Three of the natural intermediary metabolites of 1alpha,25(OH)(2)D(3) derived via the C-24 oxidation pathway namely, 1alpha,24(R),25-trihydroxyvitamin D(3), 1alpha,25-dihydroxy-24-oxovitamin D(3) and 1alpha,23(S),25-trihydroxy-24-oxovitamin D(3) [1alpha,23(S),25(OH)(3)-24-oxo-D(3)] were almost as potent as 1alpha,25(OH)(2)D(3) in terms of their ability to differentiate HL-60 cells into monocytes/macrophages. We then selected 1alpha,23(S),25(OH)(3)-24-oxo-D(3) which has the least calcemic activity among all the three aforementioned natural intermediary metabolites of 1alpha,25(OH)(2)D(3) to examine further its effects on these cells. Our results indicated that 1alpha,23(S),25(OH)(3)-24-oxo-D(3) was also equipotent to its parent in inhibiting clonal growth of HL-60 cells and in inducing expression of CD11b protein. In summary, we report that 1alpha,25(OH)(2)D(3) is metabolized in HL-60 cells into several intermediary metabolites derived via both the C-24 and C-23 oxidation pathways but not via the C-3 epimerization pathway. Some of the intermediary metabolites derived via the C-24 oxidation pathway are found to be almost equipotent to 1alpha,25(OH)(2)D(3) in modulating growth and differentiation of HL-60 cells. In a previous study, the same metabolites when compared to 1alpha,25(OH)(2)D(3) were found to be less calcemic. Thus, the findings of our study suggest that some of the natural metabolites of 1alpha,25(OH)(2)D(3) may be responsible for the final expression of the noncalcemic actions that are presently being attributed to their parent, 1alpha,25(OH)(2)D(3).

Highly active analogs of 1alpha,25-dihydroxyvitamin D(3) that resist metabolism through C-24 oxidation and C-3 epimerization pathways

The secosteroid hormone 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] is metabolized in its target tissues through modifications of both the side chain and the A-ring. The C-24 oxidation pathway, the main side chain modification pathway is initiated by hydroxylation at C-24 of the side chain and leads to the formation of the end product, calcitroic acid. The C-23 and C-26 oxidation pathways, the minor side chain modification pathways are initiated by hydroxylations at C-23 and C-26 of the side chain and lead to the formation of the end product, calcitriol lactone. The C-3 epimerization pathway, the newly discovered A-ring modification pathway is initiated by epimerization of the hydroxyl group at C-3 of the A-ring to form 1alpha,25(OH)(2)-3-epi-D(3). A rational design for the synthesis of potent analogs of 1alpha,25(OH)(2)D(3) is developed based on the knowledge of the various metabolic pathways of 1alpha,25(OH)(2)D(3). Structural modifications around the C-20 position, such as C-20 epimerization or introduction of the 16-double bond affect the configuration of the side chain. This results in the arrest of the C-24 hydroxylation initiated cascade of side chain modifications at the C-24 oxo stage, thus producing the stable C-24 oxo metabolites which are as active as their parent analogs. To prevent C-23 and C-24 hydroxylations, cis or trans double bonds, or a triple bond are incorporated in between C-23 and C-24. To prevent C-26 hydroxylation, the hydrogens on these carbons are replaced with fluorines. Furthermore, testing the metabolic fate of the various analogs with modifications of the A-ring, it was found that the rate of C-3 epimerization of 5,6-trans or 19-nor analogs is decreased to a significant extent. Assembly of all these protective structural modifications in single molecules has then produced the most active vitamin D(3) analogs 1alpha,25(OH)(2)-16,23-E-diene-26,27-hexafluoro-19-nor-D(3) (Ro 25-9022), 1alpha,25(OH)(2)-16,23-Z-diene-26,27-hexafluoro-19-nor-D(3) (Ro 26-2198), and 1alpha,25(OH)(2)-16-ene-23-yne-26,27-hexafluoro-19-nor-D(3) (Ro 25-6760), as indicated by their antiproliferative activities.

Randomized trial of parathyroidectomy in mild asymptomatic primary hyperparathyroidism: patient description and effects on the SF-36 health survey

BACKGROUND

The treatment of patients with asymptomatic primary hyperparathyroidism remains controversial despite a National Institutes of Health consensus statement. This statement also recommended a randomized clinical trial because none exists to address this issue.

METHODS

Informed consent was obtained from 53 asymptomatic patients with confirmed asymptomatic primary hyperparathyroidism who participated in this randomized trial of parathyroidectomy versus observation. Patients completed the SF-36 Health Survey, an instrument that measures wellness, every 6 months for 2 years. Average annual changes were compared.

RESULTS

Fifty-three patients (42 female, 11 male) with asymptomatic, mild (serum calcium level, 10.1-11.5 mg/dL) asymptomatic primary hyperparathyroidism who agreed to participate were randomized into either a surgical group or an observation group. The mean calcium level was 10.31 mg/dL. The only demographic difference between groups was age, with the operative group being older (66.7 vs 62.6 years; P <.03). The scores on 2 of the 9 domains of the SF-36 were significantly different (P <.007 and <.012, respectively); both favored the operative group.

CONCLUSIONS

Improved function is seen after parathyroidectomy when compared with patients who did not undergo operation. This study supports surgical management of mild primary hyperparathyroidism at the time of diagnosis because many patients have reversible nonclassic symptoms of the disease.

1alpha,25-dihydroxy-16-ene-23-yne-vitamin D3 and 1alpha,25-dihydroxy-16-ene-23-yne-20-epi-vitamin D3: analogs of 1alpha,25-dihydroxyvitamin D3 that resist metabolism through the C-24 oxidation pathway are metabolized through the C-3 epimerization pathway

The secosteroid hormone 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] is metabolized in its target tissues through modifications of both the side chain and the A-ring. The C-24 oxidation pathway, the previously well established main side chain modification pathway, is initiated by hydroxylation at C-24 of the side chain. The C-3 epimerization pathway, the newly discovered A-ring modification pathway, is initiated by epimerization of the hydroxyl group at C-3 of the A-ring. The end products of the metabolism of 1alpha,25(OH)2D3 through the C-24 oxidation and the C-3 epimerization pathways are calcitroic acid and 1alpha,25-dihydroxy-3-epi-vitamin-D3 respectively. During the past two decades, numerous noncalcemic analogs of 1alpha,25(OH)2D3 were synthesized. Several of the analogs have altered side chain structures and as a result some of these analogs have been shown to resist their metabolism through side chain modifications. For example, two of the analogs, namely, 1alpha,25-dihydroxy-16-ene-23-yne-vitamin D3 [1alpha,25(OH)2-16-ene-23-yne-D3] and 1alpha,25-dihydroxy-16-ene-23-yne-20-epi-vitamin D3 [1alpha,25(OH)2-16-ene-23-yne-20-epi-D3], have been shown to resist their metabolism through the C-24 oxidation pathway. However, the possibility of the metabolism of these two analogs through the C-3 epimerization pathway has not been studied. Therefore, in our present study, we investigated the metabolism of these two analogs in rat osteosarcoma cells (UMR 106) which are known to express the C-3 epimerization pathway. The results of our study indicate that both analogs [1alpha,25(OH)2-16-ene-23-yne-D3 and 1alpha,25(OH)2-16-ene-23-yne-20-epi-D3] are metabolized through the C-3 epimerization pathway in UMR 106 cells. The identity of the C-3 epimer of 1alpha,25(OH)2-16-ene-23-yne-D3 [1alpha,25(OH)2-16-ene-23-yne-3-epi-D3] was confirmed by GC/MS analysis and its comigration with synthetic 1alpha,25(OH)2-16-ene-23-yne-3-epi-D3 on both straight and reverse-phase HPLC systems. The identity of the C-3 epimer of 1alpha,25(OH)2-16-ene-23-yne-20-epi-D3 [1alpha,25(OH)2-16-ene-23-yne-20-epi-3-epi-D3] was confirmed by GC/MS and 1H NMR analysis. Thus, we indicate that vitamin D analogs which resist their metabolism through the C-24 oxidation pathway, have the potential to be metabolized through the C-3 epimerization pathway. In our present study, we also noted that the rate of C-3 epimerization of 1alpha,25(OH)2-16-ene-23-yne-20-epi-D3 is about 10 times greater than the rate of C-3 epimerization of 1alpha,25(OH)2-16-ene-23-yne-D3. Thus, we indicate for the first time that certain structural modifications of the side chain such as 20-epi modification can alter significantly the rate of C-3 epimerization of vitamin D compounds.

Bone mineral density (BMD) in obesity effect of weight loss

It is generally believed that bone mineral density (BMD) is increased in obese subjects, but the effect of weight loss on BMD has not been well studied. Therefore, we evaluated BMD among 11 obese women (mean age 45.5 +/- 14.2 years) before and after weight loss achieved by ingesting an 800 calorie diet for 12 weeks. BMD measurements were made at baseline, 6 months and 1 year intervals. Urinary hydroxyproline:creatinine (H:Cr), calcium:creatinine (Ca:Cr) ratios were measured as indices of bone turnover. Mean weight at baseline was 103.8 +/- 15.8 kg and decreased to 83.2 +/- 12.2 at six months and was 85.8 +/- 14.2 kg at one year. Total body, hip and lumbar spine BMD were 1.12 +/- 0.07, .87 +/- 0.11, and 1.02 +/- 0.12 gm/cm2, respectively. Total body BMD was significantly lower at 12 months compared to baseline. No significant change was observed in BMD of the lumbar spine. There was also a significant decrease in hip BMD at six months and 12 months compared to baseline. H:Cr and Ca:Cr ratios did not change over time. We conclude that weight loss achieved by VLCD is accompanied by a statistically significant change in BMD, but the BMD remained in the normal range.

A validated LC method for the quantitative determination of celecoxib in pharmaceutical dosage forms and purity evaluation in bulk drugs

A new reversed-phase, isocratic LC method was developed for the quantitative determination of COX-2 inhibitor celecoxib in bulk drugs and in pharmaceutical dosages. The proposed method is also applicable for the purity evaluation of celecoxib in bulk drugs. 5-Methyl 2-Nitro phenol has been used as internal standard for the quantitative determination of celecoxib. The method has been completely validated and proven to be rugged. The limit of detection (LOD) and limit of quantitation (LOQ) for celecoxib impurities namely, 4-hydrazino benzene sulfonamide (Intermediate I) and 1-(4-methyl phenyl)-4,4.4-trifluro butan-1,3-dione (Intermediate II) were found to be 32.0 and 97 ng. respectively. The active pharmaceutical ingredient was extracted from its finished dosage form (capsule) using methanol. The percentage recoveries ranged from 90.7 to 93.8. The stability studies were performed for celecoxib solution placed on laboratory bench and in refrigerator for hundred days. The samples were found to be stable for the study period.

Synthesis and biological activities of the two C(23) epimers of 1alpha,23,25-trihydroxy-24-oxo-19-nor-vitamin D(3): novel analogs of 1alpha,23(S),25-trihydroxy-24-oxo-vitamin D(3), a natural metabolite of 1alpha,25-dihydroxyvitamin D(3)

In a previous report, we indicated that 1alpha,23(S), 25-trihydroxy-24-oxovitamin D(3) [1alpha,23(S), 25(OH)(3)-24-oxo-D(3)], a natural metabolite of 1alpha, 25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] is almost equipotent to 1alpha,25(OH)(2)D(3) in suppressing parathyroid hormone (PTH) secretion (Lee et al., 1997. Biochemistry 36, 9429-9437). Also, 1alpha,23(S),25(OH)(3)-24-oxo-D(3) has been shown to possess only weak in vivo calcemic actions. Thus, vitamin D(3) analogs structurally related to 1alpha,23(S),25(OH)(3)-24-oxo-D(3) may have therapeutic value. Furthermore, biologic activity studies of various synthetic analogs of 1alpha,25(OH)(2)D(3) showed that the removal of carbon-19 (C-19) reduces the calcemic activity of 1alpha, 25(OH)(2)D(3.) Therefore, in an attempt to produce vitamin D(3) analogs with a better therapeutic index, we synthesized C(23) epimers of 1alpha,23,25(OH)(3)-24-oxo-19-nor-vitamin D(3) [1alpha,23, 25(OH)(3)-24-oxo-19-nor-D(3)]. The two epimers were compared to 1alpha,25(OH)(2)-19-nor-D(3) and 1alpha,25(OH)(2)D(3) in their ability to generate biologic activities in several in vitro assay systems. In the assay measuring the suppression of parathyroid hormone (PTH) secretion in bovine parathyroid cells, 1alpha,23(S), 25(OH)(3)-24-oxo-19-nor-D(3) was as potent as 1alpha, 25(OH)(2)-19-nor-D(3) but was less potent than 1alpha,25(OH)(2)D(3). In the same assay 1alpha,23(R),25(OH)(3)-24-oxo-19-nor-D(3) exhibited greater potency than 1alpha,23(S), 25(OH)(3)-24-oxo-19-nor-D(3). In the assays measuring the ability of vitamin D compounds to inhibit clonal growth and to induce differentiation of human promyelocytic leukemia (HL-60) cells, 1alpha,23(S),25(OH)(3)-24-oxo-19-nor-D(3) was less potent than 1alpha,25(OH)(2)-19-nor-D(3) but was equipotent to 1alpha, 25(OH)(2)D(3). More importantly, in the same assays, 1alpha,23(R), 25(OH)(3)-24-oxo-19-nor-D(3) was more potent than 1alpha,23(S), 25(OH)(3)-24-oxo-19-nor-D(3) and was equipotent to 1alpha, 25(OH)(2)-19-nor-D(3). Also, the vitamin D receptor-mediated transcriptional activity of 1alpha,23(R), 25(OH)(3)-24-oxo-19-nor-D(3) was almost equal to that of 1alpha, 25(OH)(2)-19-nor-D(3), but higher than that of 1alpha,23(S), 25(OH)(3)-24-oxo-19-nor-D(3). This finding explains in part the greater in vitro biologic activities of 1alpha,23(R), 25(OH)(3)-24-oxo-19-nor-D(3). In summary, our results indicate that 1alpha,23(R),25(OH)(3)-24-oxo-19-nor-D(3) and to a lesser extent 1alpha,23(S),25(OH)(3)-24-oxo-19-nor-D(3) are potent 19-nor vitamin D(3) analogs, which suppress PTH secretion in bovine parathyroid cells and strongly inhibit clonal growth and induce differentiation of HL-60 cells in vitro.

LC method for the quantitative determination of oxaprozin and its impurities in the bulk drug

A reversed phase linear gradient liquid chromatographic method was developed for the separation and quantitative determination of the seven known process related impurities and one degraded product of oxaprozin in the bulk drug material. An Inertsil-ODS 3V (150 x 4.6 mm), 5 microm column was operated with a phosphate buffer acetonitrile gradient. Detection was carried out on a UV detector at 254 nm. This method has been proved to be accurate and sensitive. The limits of detection (LOD) and limits of quantification (LOQ) of impurities were in the order of 5-60 ng and 16-200 ng, respectively. In addition to its ruggedness and robustness, this method offers identification of all eight impurities in a single run.

LC method for the determination of assay and purity of sibutramine hydrochloride and its enantiomers by chiral chromatography

Two isocratic liquid chromatography (LC) methods have been developed for the purity estimation and quantitative determination of sibutramine HCl, using 4-chloro aniline and lovastatin as internal standards, respectively. The precision has been checked in terms of F-test variance ratio using latter method as reference. The ratio of variances of the two methods is close to unity, confirming their good precision. The correlation coefficient for linear regression is more than 0.999. The inter and intra-day precision is found to be < 1.3% RSD. The accuracy determined as relative mean error (RME) for the intra-day assay is +/- 1.7%. The enantiomeric separation of sibutramine by chiral chromatography method has been described also. This method is capable of separating the two enantiomers with a selectivity of 1.4 and a resolution of 4.0. Both methods are found to be stability indicating and useful in the quality control of the bulk material.

A validated method for the determination and purity evaluation of benazepril hydrochloride in bulk and in pharmaceutical dosage forms by liquid chromatography

A gradient liquid chromatographic (LC) method has been developed for the determination and purity evaluation of benazepril hydrochloride in bulk and pharmaceutical dosage forms. The method is simple, rapid and selective. 5-Methyl-2-nitro phenol has been used as internal standard. The method is linear in the range of 50-800 microg. The precision for inter and intra-day assay variation of benazepril hydrochloride is below 1.6% RSD. The accuracy determined as relative mean error (RME) for the intra-day assay is within +/- 2.0%. The method is stability indicating, and is useful in the quality control of bulk manufacturing and also in pharmaceutical formulations.

Effect of vitamin D nutrition on parathyroid adenoma weight: pathogenetic and clinical implications

In primary hyperparathyroidism, adenoma size is a major determinant of disease severity and manner of presentation, but the reason for the large variation in size (>100-fold) is unknown. One factor could be the level of vitamin D nutrition, because in India, where vitamin D deficiency is endemic, adenomas are larger and the disease more severe than in the U.S. Accordingly, we determined the relationship between vitamin D nutrition, as measured by serum levels of 25-hydroxyvitamin D (25OHD), and parathyroid gland weight, expressed on a logarithmic scale, in 148 U.S. patients with primary hyperparathyroidism. A significant inverse relationship was found between log gland weight as dependent variable and serum 25OHD as independent variable (r = -0.365; P < 0.0001). The only other influence on gland weight was a weak inverse correlation with age. Log gland weight as an independent variable was significantly related to adjusted calcium, PTH, and alkaline phosphatase (AP) as dependent variables. In 51 patients with serum 25OHD levels less than 15 ng/mL, gland weight, PTH, AP, and adjusted calcium were each significantly higher than in 97 patients with 25OHD levels of 15 ng/mL or more, but 1,25-dihydroxyvitamin D levels were similarly increased in both groups. In the former group the response of adjusted calcium to PTH was blunted, and the response of AP was enhanced, based on significant differences in regression slopes (P = 0.0004 and 0.0022, respectively). Suboptimal vitamin D nutrition stimulates parathyroid adenoma growth by a mechanism unrelated to hypocalcemia or 1,25-dihydroxyvitamin D deficiency and reduces the calcemic response to PTH, so that a higher PTH level and more parathyroid cells are needed to raise the patient's serum calcium to the level corresponding to the increased set-point that is characteristic of the disease. Improved vitamin D nutrition in the population is partly, perhaps largely, responsible for the historical changes in disease severity and manner of presentation that have occurred over the last 50 yr.

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.

Is there a difference between right and left femoral bone density?

Because of the known differences in bone mineral density (BMD) of the dominant and nondominant forearms, it has been customary to measure BMD of the nondominant forearm to reduce variance. However, it is less clear whether such systematic differences exist between BMD of the two hips. Accordingly, we measured BMD of both hips and the spine in 131 consecutive white women who presented to a community based private practitioner for evaluation and advice on osteoporosis. There was a highly significant correlation between BMD of the two hips at the femoral neck, trochanter, and Ward's triangle (r = 0.91, 0.93, and 0.89; p < 0.0001 for all three sites), and also between BMD at various measurement sites in the hip and the spine BMD (p < 0.0001). Although, there was no significant difference between the right and left femoral neck BMD, there were small (approximately 1-2.5%) but significant differences between BMD of the two hips at the trochanter and Ward's triangle (p = 0.008 and 0. 005, respectively). The left hip BMD was consistently higher than the right hip BMD at all measurement sites. Because of the small sample size of the left-handed persons, we were unable to determine the influence of dominant handedness on hip BMD. We concluded the following: (1) BMDs of the two hips are highly correlated at relevant measurement sites; (2) there does not appear to be a dominant hip as there is dominant forearm; (3) because of strong agreement between BMD of the two hips there is little justification to measure both hips in routine clinical practice.

Isolation and identification of 1alpha-hydroxy-24-oxovitamin D3 and 1alpha,23-dihydroxy-24-oxovitamin D3: metabolites of 1alpha,24(R)-dihydroxyvitamin D3 produced in rat kidney

1alpha,24(R)-Dihydroxyvitamin D3 [1alpha,24(R)(OH)2D3], a synthetic vitamin D3 analog, has been developed as a drug for topical use in the treatment of psoriasis. At present, the target tissue metabolism of 1alpha,24(R)(OH)2D3 is not understood completely. In our present study, we investigated the metabolism of 1alpha,24(R)(OH)2D3 in the isolated perfused rat kidney. The results indicated that 1alpha,24(R)(OH)2D3 is metabolized in rat kidney into several metabolites, of which 1alpha,24(R),25-trihydroxyvitamin D3, 1alpha,25-dihydroxy-24-oxovitamin D3, 1alpha,23(S),25-trihydroxy-24-oxovitamin D3, and 1alpha,23-dihydroxy-24,25,26,27-tetranorvitamin D3 are similar to the previously known metabolites of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. In addition to these aforementioned metabolites, we also identified two new metabolites, namely 1alpha-hydroxy-24-oxovitamin D3 and 1alpha,23-dihydroxy-24-oxovitamin D3. The two new metabolites do not possess the C-25 hydroxyl group. Thus, the metabolism of 1alpha,24(R)(OH)2D3 into both 25-hydroxylated and non-25-hydroxylated metabolites suggests that 1alpha,24(R)(OH)2D3 is metabolized in the rat kidney through two pathways. The first pathway is initiated by C-25 hydroxylation and proceeds further via the C-24 oxidation pathway. The second pathway directly proceeds via the C-24 oxidation pathway without prior hydroxylation at the C-25 position. Furthermore, we demonstrated that rat kidney did not convert 1alpha-hydroxyvitamin D3 [1alpha(OH)D3] into 1alpha,25(OH)2D3. This finding indicates that the rat kidney does not possess the classical vitamin D3-25-hydroxylase (CYP27) activity. However, from our present study it is apparent that prior hydroxylation of 1alpha(OH)D3 at the C-24 position in the 'R' orientation allows 25-hydroxylation to occur. At present, the enzyme responsible for the C-25 hydroxylation of 1alpha,24(R)(OH)2D3 is unknown. Our observation that the side chain of 1alpha,24(R)(OH)2D3 underwent 24-ketonization and 23-hydroxylation even in the absence of the C-25 hydroxyl group suggests that 1alpha,25(OH)2D3-24-hydroxylase (CYP24) can perform some steps of the C-24 oxidation pathway without prior C-25 hydroxylation. Thus, we speculate that CYP24 may be playing a dual role in the metabolism of 1alpha,24(R)(OH)2D3.

Meta-analysis of calcium bioavailability: a comparison of calcium citrate with calcium carbonate

OBJECTIVE

To perform a meta-analysis of data from available published trials comparing the bioavailability of calcium carbonate with that of calcium citrate.

DATA SOURCES

The whole set was comprised of 15 studies involving 184 subjects who underwent measurement of calcium absorption from calcium carbonate and calcium citrate. Category A excluded four studies for lack of physiological relevance, use of a mixed preparation with low content of calcium carbonate, or wide variability in results. Category B was comprised of five studies (from Category A) involving 71 subjects who took calcium supplements on an empty stomach. Category C was comprised of six studies (from Category A) involving 65 subjects who took calcium preparations with meals.

METHOD

The meta-analysis of calcium absorption data from calcium carbonate and calcium citrate, with calculation of effect size and 95% confidence intervals.

RESULTS

Calcium absorption from calcium citrate was consistently significantly higher than that from calcium carbonate by 20.0% in the whole set, by 24.0% in Category A, by 27.2% on an empty stomach, and by 21.6% with meals.

CONCLUSION

Calcium citrate is better absorbed than calcium carbonate by approximately 22% to 27%, either on an empty stomach or co-administered with meals.

Isolation and identification of 4,25-dihydroxyvitamin D2: a novel A-ring hydroxylated metabolite of vitamin D2

Vitamin D2 is less toxic in rats when compared to vitamin D3. Our laboratory has been involved in research projects which were directed towards identifying the possible mechanisms responsible for the toxicity differences between vitamins D2 and D3 in rats. The present research project was designed to isolate and identify new metabolites of vitamin D2 from serum of rats which were fed toxic doses of vitamin D2. Hypervitaminosis D2 was induced in 30 rats by feeding each rat with 1000 nmol of vitamin D2/day x 14 days. The rats were sacrificed on the 15th day and obtained 180 ml of serum. The lipid extract of the serum was directly analyzed by a straight phase HPLC system. The various vitamin D2 metabolites were monitored by their ultraviolet (UV) absorbance at 254 nm. One of the UV absorbing peaks did not comigrate with any of the known vitamin D2 metabolites. This unknown metabolite peak was further purified by HPLC and was then subjected to UV absorption spectrophotometry and mass spectrometry. The structure assignment of the new metabolite was established to be 4,25-dihydroxyvitamin D2 [4,25(OH)2D2] by the techniques of UV absorption spectrophotometry and mass spectrometry and by the new metabolite's susceptibility to sodium metaperiodate oxidation. At present the biological activity of this unique 'A-ring' hydroxylated vitamin D2 metabolite is not known. As this new metabolite is isolated from the serum of rats intoxicated with vitamin D2, we speculate that 4,25(OH)2D2 may be playing an important role in the deactivation of vitamin D2.

Calcitropic hormonal status in north Indian patients with end-stage renal disease

BACKGROUND

Bone disease in chronic renal failure has a wide spectrum that includes both high and low turnover conditions. Specific preventive and therapeutic measures require knowledge of the nature of bone involvement. Bone biopsy with static and dynamic histomorphometry is the gold standard for characterization of renal bone disease. However, non-invasive biochemical tests, especially serum intact parathyroid hormone (PTH), have a good correlation with histomorphometry. We studied the clinical and biochemical profile of bone disease in a sample of north Indian patients with chronic renal failure.

METHODS

Twenty-nine patients of chronic renal failure were evaluated clinically, radiologically (subperiosteal erosions on hand X-rays) and biochemically (serum calcium, phosphorus, total alkaline phosphatase, intact PTH, osteocalcin, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D). Bone histomorphometry could be done in 4 patients.

RESULTS

Serum intact PTH within or below the non-uraemic normal range, an index of low bone turnover, was seen in 17 (58.6%) patients. Serum osteocalcin, a bone formation marker, was within or below the non-uraemic normal range in 65.5% patients. Serum intact PTH and osteocalcin had a significant positive correlation (r = 0.6). Patient groups with clinical or radiological evidence of bone disease had serum intact PTH and osteocalcin levels comparable to those lacking such features. Serum intact PTH and total alkaline phosphatase were lower in haemodialysed (n = 25) patients than in those who had not received haemodialysis (n = 4). Low (< 10 ng/ml) serum 25-hydroxyvitamin D levels were seen in 7 (24%) patients while 1,25-dihydroxyvitamin D was low (< 15.9 pg/ml) in 20 (69%) patients. The biochemical parameters accurately reflected the bone histology (n = 4).

CONCLUSIONS

Our data show that the majority of north Indian patients with chronic renal failure have biochemical evidence of low bone turnover. Empirical use of calcium salts and active vitamin D analogues without documentation of parathyroid status carry the risk of further suppression of bone turnover.

In vitro cytotoxicity of 5-aminosubstituted 20(S)-camptothecins. Part 1

A number of 5-aminosubstituted 20(S)-camptothecin analogues were prepared via semi-synthesis starting from 20(S)-camptothecin and 9-methoxy 20(S)-camptothecin. In vitro anti-cancer activity of these analogues was determined using 60 human tumor cell line assay. Although water solubility of most of these compounds was improved compared to 20(S)-camptothecin, their anti-cancer activity was considerably diminished. However, only smaller substituents such as methylamine or hydroxylamine as present in 8s and 8t, respectively, showed good activity with improved water solubility.

Physiological significance of C-28 hydroxylation in the metabolism of 1alpha,25-dihydroxyvitamin D(2)

In our previous study, we indicated for the first time that C-28 hydroxylation plays a significant role in the metabolism of 1alpha, 25-dihydroxyvitamin D(2) [1alpha,25(OH)(2)D(2)] by identifying 1alpha,24(S),25,28-tetrahydroxyvitamin D(2) [1alpha,24(S),25, 28(OH)(4)D(2)] as a major renal metabolite of 1alpha,25(OH)(2)D(2) [G. S. Reddy and K-Y. Tserng Biochemistry 25, 5328-5336, 1986]. The present study was performed to establish the physiological significance of C-28 hydroxylation in the metabolism of 1alpha, 25(OH)(2)D(2). We perfused rat kidneys in vitro with 1alpha, 25(OH)(2)[26,27-(3)H]D(2) (5 x 10(-10)M) and demonstrated that 1alpha,24(R),25-trihydroxyvitamin D(2) [1alpha,24(R),25(OH)(3)D(2)] and 1alpha,24(S),25,28(OH)(4)D(2) are the only two major physiological metabolites of 1alpha,25(OH)(2)D(2). In the same perfusion experiments, we also noted that there is no conversion of 1alpha,25(OH)(2)D(2) into 1alpha,25,28-trihydroxyvitamin D(2 )[1alpha,25,28(OH)(3)D(2)]. Moreover, 1alpha,24(S),25,28(OH)(4)D(2) is not formed in the perfused rat kidney when synthetic 1alpha,25, 28(OH)(3)D(2) is used as the starting substrate. This finding indicates that C-28 hydroxylation of 1alpha,25(OH)(2)D(2) occurs only after 1alpha,25(OH)(2)D(2) is hydroxylated at C-24 position. At present the enzyme responsible for the C-28 hydroxylation of 1alpha, 24(R),25(OH)(3)D(2) in rat kidney is not known. Recently, it was found that 1alpha,25(OH)(2)D(3)-24-hydroxylase (CYP24) can hydroxylate carbons 23, 24, and 26 of various vitamin D(3) compounds. Thus, it may be speculated that CYP24 may also be responsible for the C-28 hydroxylation of 1alpha,24(R),25(OH)(3)D(2) to form 1alpha, 24(S),25,28(OH)(4)D(2). The biological activity of 1alpha,24(S),25, 28(OH)(4)D(2), determined by its ability to induce intestinal calcium transport and bone calcium resorption in the rat, was found to be almost negligible. Also, 1alpha,24(S),25,28(OH)(4)D(2) exhibited very low binding affinity toward bovine thymus vitamin D receptor. These studies firmly establish that C-28 hydroxylation is an important enzymatic reaction involved in the inactivation of 1alpha,25(OH)(2)D(2) in kidney under physiological conditions.