Herramienta para mejorar la eficiencia en el manejo clínico de pacientes hipertensos / Tools to improve efficiency in the clinical management of hypertensive patients

Objetivo: Crear una herramienta que permita evaluar la eficiencia de la gestión clínica de los pacientes hipertensos en atención primaria. Material y métodos: Se creó un cuestionario dirigido a los centros de atención primaria, con acceso vía Web, para la autoevaluación del manejo de la hipertensión, respecto a 5 áreas de gestión: sistemas de información; pruebas diagnósticas y analíticas; aspectos organizativos; demanda asistencial y consumo de recursos; y programas de atención continuada para profesionales y para pacientes. Previamente, un comité de expertos definió estas preguntas, así como su respuesta ideal o «control», basándose en la literatura científica o, en caso de no haber referencias publicadas, de manera consensuada por dicho comité. Se realizó un análisis descriptivo de los datos y se creó un índice de adherencia de sus resultados con respecto al «control», que oscila entre 0 (ninguna adherencia) y 1 (total adherencia). Resultados: Un total de 35 centros de salud introdujeron sus datos de gestión de pacientes hipertensos en la Web de gestión clínica. Se observó la mayor adherencia en el área «Pruebas diagnósticas y analíticas» (0,69±0,10) y la menor en el área «Programas de formación continuada para pacientes y profesionales» (0,42±0,21). Conclusiones: La eficiencia de la gestión clínica en pacientes hipertensos puede analizarse mediante la herramienta web creada para este fin. Su uso permite realizar una auditoría interna para detectar las áreas que necesitan mejoras y también sirve para hacer evaluaciones comparativas en las distintas áreas de gestión a lo largo del tiempo

Objective: To create a tool to evaluate the efficiency of the clinical management of hypertensive patients in Primary Care. Material and methods: A web-based questionnaire was designed for Primary Care centres to self-evaluate the management of hypertension in five specific areas: information systems, diagnostic and analytical tests, organisational aspects, use of resources, and continuous training programmes for patients and healthcare professionals. A committee of experts previously defined these questions and their ideal responses or "control", based on the scientific literature or, if there were no published references, by consensus of the committee. A descriptive analysis was performed on the data, and an adherence score was created that ranged from 0 (no adherence) to 1 (total adherence). Results: A total of 35 Primary Care centres entered their data into the website for the clinical management of hypertensive patients. The highest adherence to the ideal algorithm was observed in the area "Diagnostic and analytical tests" (0.69±0.10), and the lowest in "Continuous training programmes for patients and professionals" (0.42±0.21). Conclusions: The efficiency of clinical management in hypertensive patients can be analysed using the website tool created for this purpose. Its use allows an internal audit to detect the areas that need improvement, and also serves to make comparative evaluations in the different areas of management over time

[Tools to improve efficiency in the clinical management of hypertensive patients]. / Herramienta para mejorar la eficiencia en el manejo clínico de pacientes hipertensos.

OBJECTIVE: To create a tool to evaluate the efficiency of the clinical management of hypertensive patients in Primary Care. MATERIAL AND METHODS: A web-based questionnaire was designed for Primary Care centres to self-evaluate the management of hypertension in five specific areas: information systems, diagnostic and analytical tests, organisational aspects, use of resources, and continuous training programmes for patients and healthcare professionals. A committee of experts previously defined these questions and their ideal responses or "control", based on the scientific literature or, if there were no published references, by consensus of the committee. A descriptive analysis was performed on the data, and an adherence score was created that ranged from 0 (no adherence) to 1 (total adherence). RESULTS: A total of 35 Primary Care centres entered their data into the website for the clinical management of hypertensive patients. The highest adherence to the ideal algorithm was observed in the area "Diagnostic and analytical tests" (0.69±0.10), and the lowest in "Continuous training programmes for patients and professionals" (0.42±0.21). CONCLUSIONS: The efficiency of clinical management in hypertensive patients can be analysed using the website tool created for this purpose. Its use allows an internal audit to detect the areas that need improvement, and also serves to make comparative evaluations in the different areas of management over time.

Synthesis, characterization and adsorptive properties of carbon with iron nanoparticles and iron carbide for the removal of As(V) from water.

This manuscript presents the synthesis of carbon modified with iron nanoparticles (CFe) and iron carbide (CarFe) from the pyrolyzed crown leaves of pineapple (Ananas comosus) treated with iron salts. The materials that were obtained were used for the removal of As(V) from aqueous media. The carbonaceous materials were characterized by Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Mossbauer Spectroscopy. The specific area (BET), number site density and point of zero charge (pH(pzc)) were also determined. The kinetic parameters were obtained by fitting the experimental data to the pseudo-first-order and pseudo-second-order models. Different isotherm models were applied to describe the As(V) adsorption behavior. The kinetics of As(V) sorption by CFe and CarFe was well defined for the pseudo-second-order model (R(2) = 0.9994 and 0.999, respectively). The maximum As(V) uptake was 1.8 mg g(-1) for CFe and 1.4 mg g(-1) for CarFe. The results obtained indicated that both materials are equally useful for As(V) sorption. The As(V) experimental isotherm data were described by the Freundlich model for CFe and CarFe.

Cardiovascular disease in familial hypercholesterolaemia: influence of low-density lipoprotein receptor mutation type and classic risk factors.

AIM: To determine the effect of the type of mutation in low-density lipoprotein receptor gene and the risk factors associated with the development of premature cardiovascular disease (PCVD) in a large cohort of heterozygous familial hypercholesterolemia (hFH) subjects with genetic diagnosis in Spain. METHODS AND RESULTS: A cross-sectional study was conducted on 811 non-related FH patients (mean age 47.1+/-14 years, 383 males and 428 females) with a molecular defect in the low-density lipoprotein receptor (LDLR) gene from the Spanish National FH Register. Prevalence of PCVD was 21.9% (30.2% in males and 14.5% in women, P<0.001). Mean age of onset of cardiovascular event was 42.1 years in males and 50.8 years in females. Of those patients with PCVD, 59.5% of males and 27% of females suffered a second cardiovascular (CV) event. In multivariate analysis male gender, age, tobacco consumption (ever), and total cholesterol/HDL-cholesterol (TC/HDL-C) ratio were significantly associated with PCVD. Two hundred and twenty different mutations were found with a large heterogeneity. Patients carrying null-mutations had significantly higher frequency of PCVD and recurrence of CV events. No relationship with Lp(a) levels and genotype of Apo E were found. CONCLUSIONS: This study confirms the importance of identifying some classic risk factors such as smoking and TC/HDL-C ratio, and also the type of mutation in LDLR gene in order to implement early detection and intensive treatment for the prevention of cardiovascular disease in FH patients.

Effect of 1alpha,25-dihydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 on metalloproteinase activity and cell maturation in growth plate cartilage in vivo.

Recent studies indicate that 1alpha,25-dihydroxyvitamin D3 (1alpha,25[OH]2D3) and 24R,25-dihydroxyvitamim D3 (24R,25[OH]2D3) differentially regulate proliferation, differentiation, and matrix synthesis of growth plate chondrocytes. To determine whether both metabolites play the same or different roles in vivo, we used the vitamin D-deficient rat as a model. Rickets was induced and then reversed by administering a single dose of ergocalciferol, 1alpha,25(OH)2D3, or 24R,25(OH)2D3 and euthanizing the animals after 4, 24, 48, or 72 h. Growth plates were either processed for histology and histomorphometry or extracted with buffered guanidine-HCl. Neutral metalloproteinase activity in the extracts was measured by use of aggrecan-containing beads, and collagenase activity was determined by use of radioactive type I collagen. The levels of tissue inhibitor of metalloproteinases (TIMP) and plasminogen activator were also determined. The morphology of the growth plate varied as a function of treatment. While 24R,25(OH)2D3 appeared to affect cell maturation and 1alpha,25(OH)2D3 appeared to affect terminal differentiation and calcification, response to ergocalciferol was indicative of the combined responses to the individual metabolites. Enzyme activity was regulated in a differential manner. Treatment with ergocalciferol produced a rapid decline in both neutral metalloproteinase and collagenase activities that was statistically significant by 4 h. By contrast, 1alpha,25(OH)2D3 had no effect on neutral metalloproteinase activity but caused a significant decrease in both active and total collagenase activity by 4 h, while 24R,25(OH)2D3 decreased neutral metalloproteinase activity by 48 h and had no effect on collagenase activity. Ergocalciferol had no effect on TIMP levels at any time examined, whereas 1alpha,25(OH)2D3 caused an increase at 48 and 72 h and 24R,25(OH)2D3 completely blocked TIMP production at 4 and 24 h. By contrast, plasminogen activator activity by ergocalciferol was decreased at 4 h, increased by 1alpha,25(OH)2D3 at 4 and 24 h, and decreased by 24R,25(OH)2D3 at all time points examined. These in vivo results confirm our previous cell culture observations showing that growth plate chondrocytes are differentially regulated by 1alpha,25(OH)2D3 and 24R,25(OH)2D3. Moreover, they show definitively that these two vitamin D metabolites play distinct roles not only in regulating neutral metalloproteinase and collagenase activities in growth plate cartilage but in cell maturation and calcification of this tissue in vivo.

A guide to references on drugs and breastfeeding.

Many of the above references will provide the necessary information to determine the safety of drugs during breastfeeding. Because interpretation of existing data varies in these references, it is prudent to consult with more than one resource. References should be routinely updated every 1 to 2 years as new drugs and literature are made available.

Interleukin-1alpha and beta in growth plate cartilage are regulated by vitamin D metabolites in vivo.

Matrix remodeling plays a prominent role in growth plate calcification. Since interleukin-1 (IL-1) has been implicated in stimulating proteinase production and inhibiting matrix synthesis in articular cartilage, we examined whether IL-1 was present in growth plate and whether the vitamin D metabolites, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3; 1,25) and 24,25(OH)2D3 (24,25), regulate the level of IL-1 found in this tissue. Sprague-Dawley rats were placed on normal (Normal rats) or rachitogenic diet (-VDP rats). The -VDP rats were either left untreated, injected 24 h prior to euthanasia with 24,25 (-VDP+24,25 rats) or 1,25 (-VDP+1,25 rats), or were given ergocalciferol (Ergo rats) orally, 48 h prior to euthanasia. Growth plates were harvested and extracted in buffer containing 1 M guanidine. IL-1 activity was measured by adding authentic cytokine or growth plate extracts to cultures of lapine articular cartilage and assaying release of glycosaminoglycans (GAGs) and changes in collagenase and neutral metalloproteinase activity. Neutralization of activity in the extracts was performed using polyclonal antisera to IL-1alpha or IL-1beta. An ELISA was used to determine levels of IL-1alpha and beta in the extracts. All extracts contained IL-1alpha and beta, as determined by ELISA. Levels of IL-1beta, but not IL-1alpha, were affected by the vitamin D status of the animal. Extracts from -VDP+24,25 animals contained significantly more IL-1beta than any of the other treatment groups, with the level found in these animals being 3-fold higher than normal and 2-fold higher than -VDP. Extracts were also tested in the bioassay to determine the level of active cytokine present. All growth plate extracts contained activity which altered GAG and proteinase release by lapine articular cartilage. Extracts from -VDP-, -VDP+1,25-, and -VDP+Ergo-treated rats stimulated a 40% increase in glycosaminoglycan release compared with extracts from normal rats. In contrast, extracts from -VDP+24,25-treated rats stimulated a 300% increase in glycosaminoglycan release. Both collagenase and neutral metalloproteinase activity of lapine cartilage were increased after incubation with the growth plate extracts. Collagenase activity was significantly increased 8- to 13-fold by the addition of extracts from -VDP-, -VDP+24,25-, or -VDP+1,25-treated animals. Neutral metalloproteinase activity was similarly increased by 4- to 10-fold. To characterize this activity further, growth plate extracts were incubated with neutralizing antibody to IL-1alpha or beta prior to addition to the lapine articular cartilage cultures. When antibodies were used separately, only partial inhibition was observed; incubation with both antibodies blocked 25% of the glycosaminoglycan release observed without antibody and greater than 80% of the enzyme activity released by the articular cartilage cultures. The results of this study show that growth plate cartilage contains both IL-1alpha and beta and indicate that vitamin D regulates the level of IL-1 in this tissue.

Vitamin D metabolites regulate matrix vesicle metalloproteinase content in a cell maturation-dependent manner.

Matrix vesicles are extracellular organelles produced by cells that mineralize their matrix. They contain enzymes that are associated with calcification and are regulated by vitamin D metabolites in a cell maturation-dependent manner. Matrix vesicles also contain metalloproteinases that degrade proteoglycans, macromolecules known to inhibit calcification in vitro, as well as plasminogen activator, a proteinase postulated to play a role in activation of latent TGF-beta. In the present study, we examined whether matrix vesicle metalloproteinase and plasminogen activator are regulated by 1, 25(OH)2D3 and 24,25(OH)2D3. Matrix vesicles and plasma membranes were isolated from fourth passage cultures of resting zone chondrocytes that had been incubated with 10(-10)-10(-7) M24, 25(OH)2D3 or growth zone chondrocytes incubated with 10(-11)-10(-8) M 1,25(OH)2D3, and their alkaline phosphatase, active and total neutral metalloproteinase, and plasminogen activator activities determined. 24,25(OH)2D3 increased alkaline phosphatase by 35-60%, decreased active and total metalloproteinase by 75%, and increased plasminogen activator by fivefold in matrix vesicles from resting zone chondrocyte cultures. No effect of vitamin D treatment was observed in plasma membranes isolated from these cultures. In contrast, 1,25(OH)2D3 increased alkaline phosphatase by 35-60%, but increased active and total metalloproteinase three- to fivefold and decreased plasminogen activator by as much as 75% in matrix vesicles isolated from growth zone chondrocyte cultures. Vitamin D treatment had no effect on plasma membrane alkaline phosphatase or metalloproteinase, but decreased plasminogen activator activity. The results demonstrate that neutral metalloproteinase and plasminogen activator activity in matrix vesicles are regulated by vitamin D metabolites in a cell maturation-specific manner. In addition, they support the hypothesis that 1,25(OH)2D3 regulation of matrix vesicle function facilitates calcification by increasing alkaline phosphatase and phospholipase A2 specific activities as well as metalloproteinases which degrade proteoglycans.

Vitamin D regulation of metalloproteinase activity in matrix vesicles.

Matrix vesicles (MVs) are enriched in matrix metalloproteinases (MMPs) capable of degrading proteoglycans. The aim of the present study was to identify which MMPs are present in MVs and determine whether these MMPs are regulated by 1,25-(OH)2D3 [1,25] and 24,25-(OH)2D3 [24,25]. To do this, growth zone (GC) and resting zone (RC) chondrocytes were isolated from rate costochondral cartilage and placed into culture. At confluence, GCs were treated with 1,25 and RCs with 24,25 for 24 hours. MVs, plasma membranes (PMs), and conditioned media were then collected from the cultures. RTPCR demonstrated the presence of mRNA for stromelysin-1 and 72 kDa gelatinase in both RCs and GCs, Casein zymography revealed activity at M(r) 48 and 28 kDa in MV, but not PM or conditioned media; Western analysis confirmed that this activity was stromelysin-1. Gelatinolytic activity, at low levels, was also found in MVs, but not PMs or conditioned media. When enzyme activity was measured using a proteoglycan bead assay, it was found that both GCs and RCs produced MVs and PMs containing neutral metalloproteinase. Both cells also produced MVs and PMs containing plasminogen activator. The addition of 1,25 to GCs caused a significant 4- to 5-fold increase in metalloproteinase activity in MVs, but not PMs. In contrast, MVs from cultures of RCs treated with 24,25 contained decreased metalloproteinase activity; enzyme activity in PMs was unaffected by 24,25. Plasminogen activator in MVs from RC was increased by treatment with 24,25, while MV enzyme activity was decreased after treatment of GC cultures with 1,25. This study shows that both RCs and GCs produce stromelysin-1 and 72 kDa gelatinase and that these enzymes are preferentially localized in MVs. Further, MMP and plasminogen activator activities in MVs and PMs are regulated by vitamin D metabolites.

Description of a new quotient that may differentiate blood pressure profiles in essential versus Cushing's syndrome-related hypertension.

Since the presence or absence of a nocturnal decrease in blood pressure values (BP) may suggest an increased risk of visceral complications or the existence of secondary hypertension, several methods have been described for evaluating the BP profile. Nevertheless, a universally accepted system to evaluate this item has not yet been established. Our aim in this study was to test different dispersion quotients (DQ) which estimate the differences between the mean of each hour, and the mean of all the readings in the 24 h period. These quotients may be employed regarding systolic (SBP) or diastolic (DBP) blood pressure, and may be referred to the whole period of 24 h, or to the subperiods morning (m), afternoon (a) or night (n). We have studied two non selected groups of essential (n = 20) or secondary (Cushing's syndrome, n = 17) hypertensives. We observed a marked decrease in these quotients, particularly DQ-SBP and nDQ-SBP, in secondary hypertensives (respectively 10.2 +/- 2.9 vs 15.6 +/- 4.2 and 11.8 +/- 5.0 vs 20.5 +/- 6.3, p < 0.0001), thus indicating, a blunted nocturnal fall of BP in these patients. Also the DQ and particularly DQ-SBP, nDQ-SBP and nDQ-DBP, showed a high positive and negative predictive value, sensitivity and specificity for pertaining to the Cushing's syndrome group (respectively: 0.75, 0.88, 0.88, 0.75; 0.86, 0.82, 0.77 0.90; and 0.78, 0.84, 0.82, 0.80).

Influencia de la hiperinsulinemia en el perfil lipídico de los pacientes hipertensos / The influence of hyperinsulinemia in the lipid profile of hypertensive patients

Fundamentos: la hipertensión arterial y dislipidemia se asocian con una frecuencia superior a la atribuible al azar. El aumento de resistencia insulínica/hiperinsulinemia ha sido uno de los factores implicados en la patogenia de dicha asociación. En el presente trabajo se analiza el perfil lipídico de los pacientes hipertensos según el grado de insulinemia. Métodos: se determinó el perfil lipídico (colesterol total, sus fracciones unidas a las lipoproteínas de baja densidad -cLDL-, alta densidad -cHDL-, triglicéridos y apolipoproteínas A1 y B plasmáticas), en 87 pacientes. Además, se les administró una sobrecarga oral de 75g de glucosa con determinaciones de glucemia, insulinemia y péptido C a los 0, 60 y 120 minutos. Resultados: al separar los hipertensos en 2 grupos según la insulinemia alcanzada después de la sobrecarga oral de glucosa, aquellos hipertensos con mayor grado de insulinemia tenían un aumento significativo de triglicéridos (p<0,05) disminución también significativa del cHDL (p<0,001). Los hipertensos con menor insulinemia tenían un aumento significativo del colesterol total (p<0,05) y de su fracción unida a las LDL, aunque este último no fue significativo. Conclusiones: en los pacientes hipertensos se pueden observar dos perfiles lipídicos: uno ligado a la hiperinsulinemia y caracterizado por aumento de triglicéridos y disminución del cHDL y otro sin relación con la hiperinsulinemia, que se manifestaría por aumento del colesterol total y del colesterol transportado por las LDL (AU)

Influencia de la hiperinsulinemia en el perfil lipídico de los pacientes hipertensos / The influence of hyperinsulinemia in the lipid profile of hypertensive patients

Fundamentos: la hipertensión arterial y dislipidemia se asocian con una frecuencia superior a la atribuible al azar. El aumento de resistencia insulínica/hiperinsulinemia ha sido uno de los factores implicados en la patogenia de dicha asociación. En el presente trabajo se analiza el perfil lipídico de los pacientes hipertensos según el grado de insulinemia. Métodos: se determinó el perfil lipídico (colesterol total, sus fracciones unidas a las lipoproteínas de baja densidad -cLDL-, alta densidad -cHDL-, triglicéridos y apolipoproteínas A1 y B plasmáticas), en 87 pacientes. Además, se les administró una sobrecarga oral de 75g de glucosa con determinaciones de glucemia, insulinemia y péptido C a los 0, 60 y 120 minutos. Resultados: al separar los hipertensos en 2 grupos según la insulinemia alcanzada después de la sobrecarga oral de glucosa, aquellos hipertensos con mayor grado de insulinemia tenían un aumento significativo de triglicéridos (p<0,05) disminución también significativa del cHDL (p<0,001). Los hipertensos con menor insulinemia tenían un aumento significativo del colesterol total (p<0,05) y de su fracción unida a las LDL, aunque este último no fue significativo. Conclusiones: en los pacientes hipertensos se pueden observar dos perfiles lipídicos: uno ligado a la hiperinsulinemia y caracterizado por aumento de triglicéridos y disminución del cHDL y otro sin relación con la hiperinsulinemia, que se manifestaría por aumento del colesterol total y del colesterol transportado por las LDL

Connective tissue integrity is lost in vitamin B-6-deficient chicks.

The objective of the present investigation was to characterize further the connective tissue disorder produced by pyridoxine (vitamin B-6) deficiency, as previously evidenced by electron microscopy. Following the second post-natal week, fast growing male chicks were deprived of pyridoxine for a 1-mo period. Six weeks post-natally, blood concentrations in the experimental deficiency group had declined to deficiency levels as registered by low concentrations of pyridoxal phosphate (coenzyme form) in erythrocytes, but did not reach levels associated with neurological symptoms. Light microscopic study showed abnormalities in the extracellular matrix of the connective tissues. Collagen cross-links and the aldehyde contents were not significantly lower in cartilage and tendon collagens of vitamin B-6-deficient animals than in age-matched controls; also, their proteoglycan degrading protease and collagenase activities measured in articular cartilages were not greater. Thus, proteolysis was an unlikely alternative mechanism to account for the loss of connective tissue integrity. These results point to the need for further investigation into adhesive properties of collagen associated proteoglycans or other proteins in vitamin B-6-deficient connective tissue.

[Influences of hyperinsulinemia in the lipid profile of hypertensive patients]. / Influencias de la hiperinsulinemia en el perfil lipídico de los pacientes hipertensos.

BACKGROUND: Hypertension and dyslipemia are associated with a greater frequency than that randomly expected. The increase in insulinic resistance hyperinsulinemia is one of the factors implicated in the pathogenesis of this association. In the present study the lipid profile of hypertensive patients is analyzed according to the degree of insulinemia. METHODS: The lipid profile (total cholesterol, fraction linked to low density lipoproteins cLDL, high density cHDL, triglycerides and plasma apolipoproteins A1 and B were determined in 87 patients with essential high blood pressure. Moreover an oral overdose of 75 g of glucose was administered with determinations of glycemia, insulinemia and C peptide at the time of glucose administration, 60 and 120 minutes. RESULTS: Upon separation of the hypertense patients into two groups according to the insulinemia achieved following an oral overload of glucose, those hypertensives with a greater degree of insulinemia showed a significant increase in triglycerides (p < 0.05) and also a significant decrease in cHDL (p < 0.001). The hypertensive patients with lower insulinemia showed a significant increase in total cholesterol (p < 0.05) and fraction linked to LDL although the latter was not significant. CONCLUSIONS: Two different lipid profiles may be observed in hypertensive patients: one linked to hyperinsulinemia and characterized by an increase in triglycerides and a decrease in cHDL and another with no relation with hyperinsulinemia which is manifested by an increase in total cholesterol and cholesterol transported by the LDL.

Matrix vesicles produced by osteoblast-like cells in culture become significantly enriched in proteoglycan-degrading metalloproteinases after addition of beta-glycerophosphate and ascorbic acid.

Matrix vesicles, media vesicles, and plasma membranes from three well-characterized, osteoblast-like cells (ROS 17/2.8, MG-63, and MC-3T3-E1) were evaluated for their content of enzymes capable of processing the extracellular matrix. Matrix vesicles were enriched in alkaline phosphatase specific activity over the plasma membrane and contained fully active neutral, but not acid, metalloproteinases capable of digesting proteoglycans, potential inhibitors of matrix calcification. Matrix vesicle enrichment in neutral metalloproteinase varied with the cell line, whereas collagenase, lysozyme, hyaluronidase, and tissue inhibitor of metalloproteinases (TIMP) were not found in any of the membrane fractions examined. MC-3T3-E1 cells were cultured for 32 days in the presence of ascorbic acid (100 micrograms/ml), beta-glycerophosphate (5 mM), or a combination of the two, to assess changes in matrix vesicle enzymes during calcification. Ascorbate or beta-glycerophosphate alone had no effect, but in combination produced significant increases in both active and total neutral metalloproteinase in matrix vesicles and plasma membranes, with the change seen in matrix vesicles being the most dramatic. This correlated with an increase in the formation of von Kossa-positive nodules. The results of the present study indicate that osteoblast-like cells produce matrix vesicles enriched in proteoglycan-degrading metalloproteinases. In addition, the observation that matrix vesicles contain significantly increased metalloproteinases under conditions favorable for mineralization in vitro lends support to the hypothesis that matrix vesicles play an important role in extracellular matrix processing and calcification in bone.

The effects of methotrexate on normal and osteoarthritic lapine articular cartilage.

OBJECTIVE: The effects of methotrexate (MTX) on articular cartilage and its influence on the development of osteoarthritis (OA) lesions were tested in a lapine partial medial meniscectomy model. METHOD: Animals were divided into groups consisting of unoperated and operated rabbits that either received or did not receive MTX treatment. After 8 weeks knee articular condylar cartilage was examined for gross and histologic anatomy, active and total neutral metalloproteinases, tissue inhibitor of metalloproteinase (TIMP), DNA, uronic acid and hydroxyproline content. RESULTS: Carbon black retention and histologic scores revealed moderately severe changes in the OA animals with a tendency to less severe changes in OA animals receiving MTX. Unoperated animals receiving MTX had abnormal cartilage that displayed pitting and elevations in histologic score. Active and total neutral metalloproteinase and TIMP were elevated in both untreated and treated OA animals when compared to either unoperated or unoperated and treated animals. CONCLUSION: Articular cartilage with lesser amounts of neutral metalloproteinase and high amounts of TIMP levels often seen with other therapeutic modalities for OA, were not observed with MTX therapy. Our data suggest that MTX may have limited value in the treatment of OA.

Enhancement of osteoinduction by vitamin D metabolites in rachitic host rats.

Diaphyseal bone from normal Sprague-Dawley rats was delipidated in chloroform-methanol and demineralized in 0.6 N HCl at 4 degrees C. The bones were then implanted for 7-28 days into rats made rachitic by a low-phosphate, vitamin D-deficient diet (VDP-) for 3 weeks. Bones from VDP- and normal rats were also implanted into normal hosts. When normal rats were used as the host environment, a consistent sequence of cartilage induction and bone formation was observed. Demineralized rachitic bone (RB) implanted into normal host rats resulted in cartilage and bone induction similar to that seen for normal bone (NB) implants. Transmission electron microscopy of RB in normal hosts revealed morphologically normal chondrocytes and cartilage matrix with normal mineralization. In contrast, implantation of NB in VDP- hosts resulted in delayed chondrogenesis and lack of calcification. Furthermore, similar results were observed when RB was implanted into VDP- hosts. Treatment of VDP- hosts with either 1 alpha-hydroxyvitamin D3 or 24,25-dihydroxyvitamin D3 did not accelerate the sequential appearance of precartilage or cartilage. However, 24,25-(OH)2D3 administered alone or in combination with 1 alpha-OHD3 significantly increased the amount of calcified cartilage observed at 2 weeks postimplantation compared to implants from either untreated VDP-hosts or those treated only with 1 alpha-OHD3. New bone formation was observed at 4 weeks postimplantation in all vitamin D-treated groups as determined by von Kossa staining or direct electron microscope examination. There was no apparent difference in the quantitative or qualitative bone formed within the various vitamin D-treated groups. Serum calcium and phosphorus levels were lower and alkaline phosphatase levels were higher in VDP- hosts compared with normal animals or those treated with vitamin D metabolites. The results of this study show a reduction in the capacity of progenitor cells in VDP- rat hosts to respond to osteoinductive factor(s). This impaired response appears to be corrected by vitamin D metabolites.

Matrix vesicles contain metalloproteinases that degrade proteoglycans.

This study explored whether extracellular matrix processing enzymes are present in matrix vesicles produced by rat costochondral resting zone and growth zone chondrocytes in culture. It was found that there was a differential distribution of enzyme activities related to the cartilage zone from which the cells were isolated. There was a 3-fold enrichment of total and active acid metalloproteinase in growth zone chondrocyte (GC) matrix vesicles whereas no enrichment in enzyme activity was observed in resting zone chondrocyte (RC) matrix vesicles. Total and active neutral metalloproteinase were similarly enriched 2-fold in GC matrix vesicles. TIMP, plasminogen activator and beta-glucuronidase activities were highest in the plasma membranes of both cell types. No collagenase, lysozyme, or hyaluronidase activity was found. The data indicate that matrix vesicles are selectively enriched in enzymes that degrade proteoglycans. The highest concentrations of these enzymes are found in matrix vesicles produced by growth zone chondrocytes, suggesting that this may be a mechanism by which the more differentiated cell modulates the matrix for calcification.

Matrix vesicles are enriched in metalloproteinases that degrade proteoglycans.

This study examined the presence of extracellular matrix processing enzymes in matrix vesicles produced by rat costochondral resting zone and growth zone chondrocytes in culture. Optimum procedures for the extraction of each enzyme activity were determined. Enzyme activity associated with chondrocyte plasma membrane microsomes was used for comparison. There was a differential distribution of the enzyme activities related to the cartilage zone from which the cells were isolated. Acid and neutral metalloproteinase (TIMP), plasminogen activator, and beta-glucuronidase were highest in the growth zone chondrocyte (GC) membrane fractions when compared with matrix vesicles and plasma membranes isolated from resting zone chondrocyte (RC) cultures. There was a threefold enrichment of total and active acid metalloproteinase in GC matrix vesicles, whereas no enrichment in enzyme activity was observed in RC matrix vesicles. Total and active neutral metalloproteinase were similarly enriched twofold in GC matrix vesicles. TIMP, plasminogen activator, and beta-glucuronidase activities were highest in the plasma membranes of both cell types. No collagenase, lysozyme, or hyaluronidase activity was found in any of the membrane fractions. The data indicate that matrix vesicles are selectively enriched in enzymes which degrade proteoglycans. The highest concentrations of these enzymes are found in matrix vesicles produced by growth zone chondrocytes, suggesting that this may be a mechanism by which the more differentiated cell modulates the matrix for calcification.