Hailey-Hailey disease successfully treated with vitamin D oral supplementation.

Hailey-Hailey disease (HHD) also known as familial benign chronic pemphigus is a rare autosomal dominant genodermatosis. HHD treatment is often not satisfactory and hence, various modalities of treatment have been tried. We describe the case of a 37-year-old woman with a 2 years history of macerated erythematous plaques along with erosions, fissures, and crusts located on axillae and submammary areas, successfully treated with only oral supplementation of vitamin D (800 I.U./die) for 3 months. We reported this case to suggest that oral vitamin D may be enumerated in the various treatments proposed for HHD so far due to its rapid efficacy on skin lesions and symptoms.

1, 25-dihidroxivitamina-D 3 sobre as características ósseas de frangos de corte fêmeas / 1, 25-dihydroxyvitamin-D3 over bony characteristics of female broilers

Objetivou-se avaliar as características dos tibiotarsos de frangos de corte fêmeas. As variáveis analisadas foram os pesos in natura, secos e desengordurados, o comprimento, os diâmetros, a resistência óssea, o índice de Seedor (IS), os percentuais de proteínas colagenosas (PC), as proteínas não colagenosas (PNC), os minerais (cálcio, fósforo, potássio e sódio) e as cinzas. Foram utilizadas 648 aves, da marca comercial Cobb®, em um delineamento em blocos ao acaso, com seis tratamentos e seis repetições, com 18 aves por unidade experimental. Os tratamentos consistiram na suplementação de 0,00; 0,50; 1,00; 1,50; 2,00 e 2,50 µg de 1,25-dihidroxivitamina-D3 (1,25(OH)2D3)/kg de ração. Aos 21 e 35 dias de idade, as aves foram pesadas e uma ave por unidade experimental (UE) com o peso médio da UE foi eutanasiada para a obtenção dos tibiotarsos e subsequente análise dos parâmetros ósseos. As variáveis métricas, bem como a composição orgânica (PC), a densidade (IS) e a resistência à quebra dos ossos das aves, não foram influenciadas pelos tratamentos. No recebimento de 2,50 µg de 1,25(OH)2D3/kg de ração, observou-se maior retenção mineral (cinzas) nos ossos das aves aos 35 dias de idade.(AU)

This study aimed to evaluate the characteristics of tibiotarsus of female broilers. The variables analyzed were the weights in natura, dry and degreased, length, diameter, bone strength, Seedor index, percentage of collagenous protein (CP), non-collagenous proteins (NCP), minerals (calcium, phosphorus, potassium and sodium), and ash. Six hundred forty-eight, Cobb® birds were used, a design of randomized blocks with six treatments and six replicates of 18 birds each. The treatments consisted of supplementation of 0.00; 0.50; 1.00; 1.50; 2.00 to 2.50 µg of 1,25-dihydroxyvitamin-D3 (1,25(OH)2D3)/kg of ration. At 21 and 35 days of age the birds were weighed and a unit/experimental unit (EU) with the EU average weight was euthanized to obtain the tibiotarsos and subsequent analysis of the bone parameters. The metric variables, as well as the organic composition (CP), density (IS) and resistance to breakage of the bones of the birds were not affected by treatments. Upon reception of 2.50 µg of 1,25(OH)2D3/kg ration, there was a higher mineral retention (ashes) in the bones of female broilers at 35 days of age.(AU)

Effect of narrow band ultraviolet B phototherapy as monotherapy or combination therapy for vitiligo: a meta-analysis.

BACKGROUND: The treatment of vitiligo is still one of the most difficult dermatological challenges, although there are many therapeutic options. Narrow band ultraviolet B (NB-UVB) phototherapy is considered to be a very important modality for generalized vitiligo. OBJECTIVE: The aim of this study was to explore whether a combination of NB-UVB and topical agents would be superior to NB-UVB alone for treating vitiligo. METHODS: We searched the electronic databases such as PUBMED, EMBASE, Cochrane Library, and Web of Science. The primary outcome was the proportion of ≥50% repigmentation (a clinical significance), and secondary outcome was the proportion of ≥75% repigmentation (an excellent response). RESULTS: Seven randomized controlled trials (RCTs) involving 240 patients (413 lesions) were included in this meta-analysis. The study showed no significant difference between NB-UVB combination therapy (NB-UVB and topical calcineurin inhibitor or vitamin D analogs) and NB-UVB monotherapy in the outcomes of ≥50% repigmentation and ≥75% repigmentation. However, lesions located on the face and neck had better results in ≥50% repigmentation (RR = 1.40, 95% CI 1.08-1.81) and ≥75% repigmentation (RR = 1.88, 95% CI 1.10-3.20) with NB-UVB and topical calcineurin inhibitor combination therapy vs. NB-UVB monotherapy. CONCLUSIONS: The meta-analysis suggested that adding neither topical calcineurin inhibitors nor topical vitamin-D3 analogs on NB-UVB can yield significantly superior outcomes than NB-UVB monotherapy for treatment of vitiligo. However, addition of topical calcineurin inhibitors to NB-UVB may increase treatment outcomes in vitiligo affecting face and neck.

Tacalcitol: a useful adjunct to narrow-band ultraviolet-B phototherapy in vitiligo.

BACKGROUND: Phototherapy especially narrow-band UV-B (NBUVB) has been considered as mainstay of therapy in nonsegmental vitiligo (generalized type). Topical tacalcitol has also been claimed to be effective, either as monotherapy or as combination therapy. PURPOSE: Comparison of clinical efficacy and safety of NBUVB in combination with topical tacalcitol vs. NBUVB alone in vitiligo. MATERIAL & METHODS: Thirty patients with symmetrical vitiliginous lesions were enrolled for 24 weeks. Patients were instructed to apply tacalcitol ointment on right side of body once daily. In addition, the whole body was irradiated with NBUVB thrice weekly. All the patients were examined, and lesional photography was done. Patients were also followed up for 6 months post-treatment. RESULTS: Our study resulted in two key findings: (1) There was a statistically significant difference in mean percentage of repigmentation at 8, 16 and 24 weeks between combination therapy and NBUVB. (2) The mean cumulative dose and number of treatment sessions for initial repigmentation were significantly lower with combination therapy. No serious adverse effects were observed during the study period. CONCLUSION: Topical tacalcitol potentiates efficacy of NBUVB as it enhances extent of pigmentation, decrease time to repigmentation and lowers the cumulative doses of NBUVB, thereby leading to greater patient satisfaction and improved compliance.

Vitamin D analogs decrease in vitro secretion of RANTES and enhance the effect of budesonide.

PURPOSE: Eosinophils appear to be central inflammatory cells in the pathogenesis of rhinosinusitis with nasal polyps (NP). One of the most predominantly recognized eosinophil chemoattractants is RANTES. The aim of this study was to assess the influence of vitamin D (VD) derivates on RANTES expression in the culture of nasal polyp fibroblasts. MATERIAL AND METHODS: NP fibroblast cell cultures derived from 16 patients with NP were first stimulated with bacterial LPS and than incubated in increasing concentrations (from 10(-7)M to 10(-4)M) of calcitriol, tacalcitol or budesonide and in combination with one of VD derivate with budesonide in 1:1, 1:3 and 3:1 ratios. Quantitative analysis of RANTES level was conducted in culture supernatants using an ELISA method. RESULTS: The highest calcitriol concentration (10(-4)M) as well as tacalcitol at 10(-5)M and 10(-4)M reduced RANTES production significantly compared to the control (201.1pg/ml, 338.7pg/ml, 211.3pg/ml v 571.78pg/ml; p<0.05). Budesonide and calcitriol administered in 1:3 ratio and budesonide and tacalcitol in 1:1 and 1:3 reduced RANTES concentration significantly better than each of the drug used in monotherapy (p<0.05). Budesonide and tacalcitol in 1:1 and 1:3 ratios suppressed RANTES production to the lowest level (171.8±97.6pg/ml and 178.7±105.22pg/ml, respectively). CONCLUSION: Active VD compounds via downregulation of RANTES production exert a potential role as a complementary element in the therapy of chronic rhinosinusitis with NP. Compounds consisting of budesonide and VD derivate have an advantage over both drugs used in monotherapy.

Clinical evaluation of topical tacalcitol efficacy in extending the remission period between nb-UVB phototherapy cycles in psoriatic patients.

Psoriasis is a very common dermatological disease affecting a large part of the world population. In its most common form, psoriasis vulgaris, many topical drugs are available to treat the localized forms, and the recurrence of the dermatosis. Among topicals, tacalcitol has been proven to be effective and devoid of side effects which are typical of Vitamin-D3 analogues or derivates. The aim of this retrospective study was to evaluate the efficacy of topical tacalcitol vs. calcipotriol and emollient treatment of the first recurring lesion in order to induce a longer remission period before the retreatment with nb-UVB phototherapy in a population of 90 psoriatic patients. In this trial, the time between the first relapsing plaque appearance and retreatment with nb-UVB resulted in 25, 16 and 11 days for tacalcitol, calcipotriol and emollient respectively, with a statistically significant difference for tacalcitol (p < 0.0001). These results proved that tacalcitol treatment is effective in increasing the time interval in consecutive phototherapy cycles and in reducing the total amount of UV exposure.

Influence of vitamin D(3) analogues in combination with budesonid R on proliferation of nasal polyp fibroblasts.

UNLABELLED: Vitamin D (VD) and its different analogues, besides their classic role as regulators of calcium and phosphor homeostasis, have emerged as a large family of antiproliferative agents. Such properties suggested VD potential as a therapy for chronic inflammatory diseases, including nasal polyposis (NP). NP growth involves both an inflammatory process and the proliferation of fibroblast as an important factor inducing aberrations in the phenotype of the epithelium. The aim of this study was to investigate the possible influence of 1alpha,25-dihydroxyvitamin D(3) (calcitriol) and 1alpha,24(R)-dihydroxyvitamin D(3) (tacalcitol) in monotherapy and in combination with budesonid R (BR) on NP fibroblast proliferation. MATERIAL AND METHODS: The study involved 26 samples of NP. NP cells were cultured on 96-well plates beginning with a concentration of 5 x 10(3) cells per well with RPMI 1640 medium supplemented with antibiotics and 10% foetal bovine serum. After the fourth to sixth passage the medium was replaced with a nutrient medium with calcitriol or tacalcitol in a defined concentration (from 10(-9) M to 10(-3) M) alone or in combination with BR in 1:1, 1:3 or 3:1 ratios, each at concentrations from 10(-5) M to 10(-3) M. RESULTS: Growth inhibition of nasal fibroblasts exposed to calcitriol or tacalcitol was noted. Significant antiproliferating activity was observed at calcitriol concentrations of 10(-4) M and 10(-3) M after 48 h, and at a concentration of 10(-3) M after 72 h with the percentage of proliferating cells reduced to 30% compared to the control samples (P < 0.05). In cells treated with tacalcitol the maximal effect was seen at 10(-4) M after 48 h and at 10(-3)M after 72 h with a 60% inhibition with respect to the control (P < 0.05). The inhibition of fibroblast proliferation reached the maximal level when they were exposed to calcitriol: BR (1 : 1) or tacalcitol: BR (1 : 1), each at a concentration of 10(-4) M, after 72 h (82% and 69%, respectively). CONCLUSIONS: The antiproliferative activity of calcitriol and tacalcitol in NP cultures was confirmed. Because of its lower toxicity and higher activity tacalcitol seems to be the more promising agent in NP therapy, both as a single medication and in treatment protocols with BR.

Randomized, double-blind clinical trial to evaluate the efficacy of topical tacalcitol and sunlight exposure in the treatment of adult nonsegmental vitiligo.

BACKGROUND: Vitiligo is a common skin disease which is difficult to treat. Approximately half of patients acquire the disease before the age of 20 years. This disease has a high stigmatizing impact but no ideal, aetiology-oriented, effective therapy has been found to date. Tacalcitol and other vitamin D analogues have been shown to have stimulating activity both on immunomodulatory mediators and on melanocytes in lesional skin. OBJECTIVE: To investigate the efficacy and safety of tacalcitol ointment plus sunlight exposure in the treatment of nonsegmental vitiligo. METHODS: A single-centre, randomized, double-blind, vehicle-controlled study including 80 patients with nonsegmental vitiligo was carried out in a specialized outpatient dermatology clinic within a tertiary care, university-affiliated hospital in Spain. Efficacy was assessed by quantification of the lesional repigmentation area at the end of the study compared with the baseline. Tacalcitol (n = 40) or matching placebo ointment (n = 40) was applied once a day at night. Daily exposure to sunlight for 30 min was performed. Treatment was continued for 4 months. The response of the lesions was clinically verified every 2 weeks by a blinded medical investigator. All adverse effects were recorded. RESULTS: Eighty adult patients with nonsegmental vitiligo were recruited. Over 16 weeks, 64 patients completed the study requirements. There was no significant difference in the repigmentation response at the 16-week time point between the vehicle + sunlight exposure and the tacalcitol + sunlight exposure groups. No reduction in the size of the lesions > 25% was observed in the tacalcitol-treated patients. No serious adverse effects were observed. CONCLUSION: The combination of tacalcitol with heliotherapy has no additional advantages compared with heliotherapy alone.

Topical becocalcidiol for the treatment of psoriasis vulgaris: a randomized, placebo-controlled, double-blind, multicentre study.

BACKGROUND: Becocalcidiol is a vitamin D(3) analogue which has not caused hypercalcaemia or significant irritation in preclinical trials. OBJECTIVES: To evaluate the efficacy and safety of two dosing regimens of becocalcidiol ointment (low dose = 75 microg g(-1) once daily for 8 weeks; high dose = 75 microg g(-1) twice daily for 8 weeks) in the treatment of plaque-type psoriasis. METHODS: One hundred and eighty-five subjects with chronic plaque-type psoriasis affecting 2-10% of their body surface area took part in a multicentre, double-blind, parallel-group, vehicle-controlled, randomized controlled trial comparing topical application of placebo, becocalcidiol 75 microg g(-1) once daily (low dose) or becocalcidiol twice daily (high dose) for 8 weeks. Main outcomes included Physician's Static Global Assessment of Overall Lesion Severity (PGA) score; Psoriasis Symptom Severity (PSS) score; adverse events; and laboratory assessment. RESULTS: In the intent-to-treat population at week 8, high-dose becocalcidiol was statistically superior to vehicle [P = 0.002; 95% confidence interval (CI) 6.7-32.2], with 16 of 61 (26%) subjects achieving a PGA score of clear or almost clear. Greater improvement in PSS score was seen with high-dose becocalcidiol than with vehicle, but this result did not quite achieve statistical significance (P = 0.052; 95% CI -16.2 to 0.1). In all groups, therapy was safe and well tolerated, with fewer subjects experiencing irritation than is reported in studies using calcipotriol. CONCLUSIONS: Treatment with high-dose topical becocalcidiol for 8 weeks led to almost or complete clearing of moderate plaque-type psoriasis in over a quarter of patients. Therapy was safe and well tolerated.

Topical tacalcitol and 308-nm monochromatic excimer light: a synergistic combination for the treatment of vitiligo.

BACKGROUND/PURPOSE: To study and compare the efficacy of combined 308-nm monochromatic excimer light (MEL) therapy with tacalcitol vs. that of MEL 308-nm therapy alone in treatment of vitiligo. METHODS: Thirty-eight patients with vitiligo were enrolled in a single-blind, within patient controlled clinical trial. Symmetrical or nearby lesions were randomly applied with either topical tacalcitol cream or vehicle. Each lesion was treated weekly with the 308-nm MEL, for a total of 12 sessions. Patients were examined at monthly intervals. The mean number of sessions and the cumulative dosage for initial repigmentation were calculated. RESULT: Thirty-five patients were evaluated. Treatment with tacalcitol and MEL resulted in higher percentages for excellent repigmentation (25.7%) compared with vehicle and MEL (5.7%) (P<0.05). Percentages for total response were 71.4% and 60%, respectively (P>0.05). The mean+/-SEM cumulative dose and number of excimer light exposures for initial repigmentation were, respectively, 3.93+/-0.59 J/cm2 and 4.52+/-0.49 at the tacalcitol side, and, respectively, 4.99+/-0.68 J/cm2 and 5.3+/-0.52 at the vehicle side (P<0.05). CONCLUSION: Our results have shown that concurrent topical tacalcitol potentiates the efficacy of the 308-nm MEL in the treatment of vitiligo, and that this combination achieves earlier pigmentation with a lower total dosage.

Profile of clinical efficacy and safety of topical tacalcitol.

Several topical treatments such as ointments, keratolytics, dithranol, tar, corticosteroids and Vitamin D3 analogues are commonly used in the treatment of mild and/or moderate psoriasis. These treatments can be associated with a variety of local and systemic side effects, as well as to very often unsatisfactory results. The purpose of this critical review of the literature is to evaluate the efficacy and tolerability of the synthesis of new analogues of the Vitamin D3 Tacalcitol, which is formulated in ointment form at a concentration of 4 microg/g, for the treatment of mild and/or moderate psoriasis (involvement of <20% of the surface of the skin) and to evaluate whether this drug can be used in the treatment of other skin conditions. Based on existing data in the literature, Tacalcitol is an effective drug for the topical treatment of psoriasis and is also able to ensure that the effects last over time, even after treatment has stopped. Tacalcitol is also well tolerated because the onset of side effects, such as local irritation, pruriginous or burning sensations, were reported in only a small percentage of the subjects who were treated. Lastly, the marked regulatory effects it has on the proliferation and differentiation of keratinocytes, as well as on the immunocompetent cells, has led to suggestions that Tacalcitol may be used in other keratinisation disorders and in some hyperproliferative skin diseases. Evaluation of the effective indications to use in these conditions still requires further data confirming its effectiveness, opening the way to wider use of this molecule in dermatology.

Non-invasive evaluation of tacalcitol plus puva versus tacalcitol plus UVB-NB in the treatment of psoriasis: "right-left intra-individual pre/post comparison design".

Photochemotherapy with psoralen plus ultraviolet A(PUVA) and phototherapy with UVB narrow band (UVB-NB) are used in the treatment of psoriasis. Numerous studies have shown that the additional administration of either topical or systemic antipsoriatic agents may effectively increase the efficacy of these therapies. This study aimed to compare through objective data the efficacy of topical tacalcitol in combination with PUVA or UVB-NB versus PUVA and UVB-NB monotherapy in the treatment of mild to moderate chronic plaque psoriasis. Modified Psoriasis Area and Severity Index (PASI) score, transepidermal water loss (TEWL) and stratum corneum hydration were used to monitor the restoration of skin barrier in the psoriatic plaques of 40 patients during photochemotherapy. The study was a right-left, intra-individual, pre/post comparison trial. PUVAand UVB-NB treatments were given three times a week. On those plaques localized on the right side of the body tacalcitol ointment was applied once a day, in the evening. Corneometry, TEWL and modified PASI score were used to evaluate the response to the treatment at baseline, one month and two months. Thirty-six of the forty enrolled subjects completed the study. The comparison between combination treatments and the PUVA/UVB-NB monotherapy showed no significant differences with regard to modified PASI index. However, significant differences were recorded with regard to TEWL and corneometry. The combination of tacalcitol plus PUVA or tacalcitol plus UVB-NB restored epidermal barrier functions as well as skin hydration faster than PUVA or UVB-NB monotherapy (TEWL: p=0.0050 and corneometry: p=0.003). The combination of tacalcitol plus UVB-NB allowed a better restoration of skin barrier functions than tacalcitol plus PUVA (p=0.013). In conclusion, the combination of tacalcitol plus PUVA or plus UVB-NB improves the therapeutic result. In addition, the data from TEWL and skin hydration suggest a means in which tacalcitol plus UVB-NB induces a better normalization of skin biophysical parameters.

Topical tacalcitol treatment for psoriasis.

Multiple studies have shown the benefit of topical tacalcitol treatment for chronic plaque psoriasis. Tacalcitol ointment 4 micrograms/g is efficacious and well tolerated as both monotherapy and in combination with other treatments such as ultraviolet light therapy. It can be used all over the body including the face and scalp.

Increase of bone volume in vitamin D-repleted rats by massive administration of 24R,25(OH)2D3.

A large dose of 24R,25(OH)2D3 was administered to the vitamin D-repleted rat to examine its effect on the bone. Male Wistar rats were fed a diet containing 0, 0.025, 1.25, 4.0, and 12.5 ppm 24R, 25(OH)2D3 for 2 years starting at age 6 weeks. The estimated amounts of daily intake of 24R,25(OH)2D3 were 0, 93, 4640, 14680, and 49580 ng/100 g body weight, respectively. No notable difference was found in either the weight or the death rate of the animal. The long-term administration of massive doses of 24R,25(OH)2D3 did not lead to hypercalcemia nor did it affect the blood phosphorus, alkaline-phosphatase, or creatinine levels. Radiographs revealed a striking increase in the bone density on the bones from the animals treated with 1.25 ppm or more 24R,25(OH)2D3. Direct single photon absorptiometry revealed a dose-dependent increase in total bone minerals of both the femur and coccyx. Histological examination revealed a marked increase in the cortical thickness of the femur as well as in the cancellous bone volume of the coccyx. Polarizing microscopy demonstrated the lamellar structure of the bone, and undecalcified sections confirmed the increase of mineralized bone. Ash weight, calcium, phosphorus, and magnesium contents on the tibia and fibula also indicated the ascending dose-dependent increase up to 150% of the control. The parameters of bone size were not altered in any group. These results clearly suggest that 24R,25(OH)2D3 given in massive doses has the pharmacological action of increasing bone volume in the rat without causing remarkable hypercalcemia.

Aluminum and renal osteodystrophy.

Evidence has emerged over the last several years indicating that aluminum accumulation in patients with chronic renal failure can cause certain forms of renal osteodystrophy, in particular osteomalacia and an aplastic lesion. The lines of evidence include epidemiological associations, chemical measurement and histological staining of bone aluminum, animal models of aluminum loading, and a favorable response to the removal of aluminum by chelation therapy. The primary sources of aluminum are dialysate solutions prepared from water with a high aluminum content and the oral ingestion of aluminum-containing phosphate binders. Desferrioxamine, a chelating agent with a high affinity for aluminum, can be used to remove aluminum during dialysis by increasing ultrafilterable plasma aluminum; preliminary results show that symptomatic patients markedly improve, both clinically and in their bone histology, after long-term chelation therapy with desferrioxamine. Treating water to ensure that aluminum levels are appropriately reduced in dialysate and the development of non-aluminum-containing phosphate binders are necessary to prevent aluminum-related osteodystrophy.

[Effects of diets including an active vitamin D 3 metabolite and different contents of calcium and phosphorus on the state of blood free amino acids in hypokinetic rats]. / Vliianie diet s aktivnym metabolitom vitamina D 3 i razlichnym soderzhaniem kal'tsiia i fosfora na sostav svobodynykh aminokislot krovi krys pri gipokinezii.

Some aspects of amino acid metabolism in rats exposed to 30 days of hypokinesia were explored. The animals were placed on the diets with varying Ca/P ratio, containing 24, 25-dihydroxycholecalciferol (24, 25 (OH)2)D3, an active vitamin D3 metabolite. It was demonstrated that high consumption of phosphorus brought about an appreciable reduction in the blood amino acid pool, thus aggravating the body response characteristic for hypokinesia. The use of 24, 25 (OH)2D3 promoted the recovery of the amino acid status of hypokinetic rat blood, while the optimization of the Ca and P content in the diet was absolutely indispensable.

Effect of oral 1,25-dihydroxyvitamin D and calcium on glucocorticoid-induced osteopenia in patients with rheumatic diseases.

Twenty-three rheumatic disease patients with glucocorticoid-induced osteopenia (defined by measurement of forearm bone mass) completed an 18-month double-blind, randomized study to assess the effect of oral calcium and 1,25-dihydroxyvitamin D (1,25-OH2D) or calcium and placebo on bone and mineral metabolism. Intestinal 47Ca absorption was increased (P less than 0.05) and serum parathyroid hormone levels were suppressed (P less than 0.01) by 1,25-OH2D (mean dose 0.4 micrograms/day); however, no significant gain in forearm bone mass occurred, and bone fractures were frequent in both groups. In the 1,25-OH2D group, histomorphometric analysis of iliac crest biopsy specimens demonstrated a decrease in osteoclasts/mm2 of trabecular bone (P less than 0.05) and parameters of osteoblastic activity (P less than 0.05), indicating that 1,25-OH2D reduced both bone resorption and formation. We conclude that 1,25-OH2D should not be used for treatment of glucocorticoid-induced osteopenia. Since patients receiving calcium and placebo did not exhibit a loss of forearm bone mass, elemental calcium supplementation of 500 mg daily might be useful to maintain skeletal mass in patients receiving long-term glucocorticord therapy.

Studies on the etiology of tibial dyschondroplasia in chickens.

Experiments have been conducted to obtain information on the cause of tibial dyschondroplasia in chickens. All studies were conducted with corn-soybean meal practical-type diets and chicks from 1 day to 3 or 4 weeks of age. A high calcium and low phosphorus content of the diet and a wide calcium:phosphorus ratio in the diet decrease the incidence of tibial dyschondroplasia in broiler chickens. Increasing the chloride level of the diet increased the incidence of tibial dyschondroplasia. Increasing the magnesium content of the diet decreased tibial dyschondroplasia; however, the effect of magnesium was not as strong as that of calcium. The addition of sodium sulfate to the diet had no effect on the incidence of tibial dyschondroplasia. Five broiler strain crosses were all susceptible, although to a variable extent, to the development of tibial dyschondroplasia, whereas Single Comb White Leghorn chickens did not develop the disease. Male chicks developed tibial dyschondroplasia with a higher incidence than did female chicks. Supplementation of the chickens with 20 ng/day of either 1,25-dihydroxycholecalciferol [1,25(OH)2D3] or 24,25-dihydroxycholecalciferol [24,25(OH)2D3] had no effect on the incidence of tibial dyschondroplasia. J. Nutr . 114: 1001-1013, 1984.

[Effect of 24,25-dioxycholecalciferol on calcium-phosphorus metabolism and bone tissue in rats with experimental renal failure]. / Vliianie 24,25-dioksikholekal'tsiferola na kal'tsii-fosfornyi obmen i kostnuiu tkan' pri eksperimental'noi pochechnoi nedostatochnosti u krys.

Experimental chronic renal failure (CRF) in rats gave rise to azotemia, hyperphosphatemia, reduction in the proportion of the diaphyses, decrease in them of calcium, phosphorus and hydroxyproline, and to the lowering of the calcium content in the epiphyses. Administration to the animals of 0.025 microgram of 1,25-dioxycholecalciferol (1,25(OH)2D3) a day did not make the indicators under consideration return to normal. At the same time 1,25(OH)2D3 enhanced the degree of hyperphosphatemia and demineralization of the epiphyses, provoked moderate hypercalcemia and dramatically enhanced calcinosis in the aorta and in the remainder of the kidney. Administration of 24,25-dioxycholecalciferol (24,25(OH)2D3) in a dose of 0.25 microgram made the majority of the indicators return to normal, increasing the proportion of the diaphyses and the content in them of calcium and phosphorus, reducing the blood phosphorus content and the degree of azotemia. Furthermore, 24,25(OH)2D3 raised the collagen content in the diaphyses and epiphyses. A higher dose of 24,25(OH)2D3 (1.25 microgram) did not appear more effective. In none the doses applied, 24,25(OH)2D3 produced hypercalcemia or calcinosis. Combination of 1,25(OH)2D3 in a dose of 0,025 microgram and 24,25(OH)2D3 in a dose of 1,25 microgram slightly reduced the hypercalcemic, hyperphosphatemic and calcinosis-inducing effects of 1,25(OH)2D3, completely prevented osteoporotic alterations in the diaphyses, but enhanced the demineralization in the epiphyses, which may point to the advisability of reducing the doses of these metabolites on combined use. The data obtained indicate that 24,25(OH)2D3 is a more effective and safer agent for correcting the disturbances of the phosphorus-calcium metabolism and osseous lesions in CRF than 1,25(OH)2D3.