Comparative Assessment of Contact Osteogenesis at the Titanium Implant-Bone Junction in Male Rabbits with Dissimilar Femoral Defects / Evaluación Comparativa de la Osteogénesis de Contacto en la Unión entre el Hueso y el Implante de Titanio en Conejos Macho con Defectos Femorales Diferentes

SUMMARY: Traumatized bone tissue has the capacity to repair itself so that it eventually regains its almost original form, even in the case of artificially inserted implants. The process that stays at the base of the regeneration is represented by osteogenesis or remote osteogenesis. The major difference between the two types of bone formation is the location of the cement line, which is located on the surface of the implant for contact osteogenesis and on the surface of the bone defect for remote osteogenesis. The aim of the present study was to assess the contact osteogenesis in the case of inserted titanium screws in holes with diameters of 1.8 mm and 1 mm respectively. The obtained results show, in the case of the groove with 1.8 mm that the newly proliferated bone represents 73.85 % of the total area, while in the case of the groove with 1 mm in diameter the value of the newly proliferated bone is 26.15 %. In conclusion, the insertion of titanium screws by self-tapping into the hole smaller than the core of the screw is accompanied by bone proliferation by contact osteogenesis much more modest than in the case of insertion into the hole larger than the core of the screw.

El tejido óseo traumatizado tiene la capacidad de reparar en forma espontánea, de modo que eventualmente recupera su forma casi original, incluso en el caso de implantes insertados artificialmente. El proceso que queda en la base de la regeneración está representado por la osteogénesis u osteogénesis a distancia. La principal diferencia entre los dos tipos de formación ósea es la ubicación de la línea de cemento, que se encuentra en la superficie del implante para la osteogénesis de contacto y en la superficie del defecto óseo para la osteogénesis remota. El objetivo del presente estudio fue evaluar la osteogénesis de contacto en el caso de tornillos de titanio insertados en forámenes con diámetros de 1,8 mm y 1 mm respectivamente. Los resultados obtenidos muestran, en el caso del surco de 1,8 mm que el hueso neoproliferado representa el 73,85 % del área total, mientras que en el caso del surco de 1 mm de diámetro el valor del hueso neoproliferado es del 26,15 %. En conclusión, la inserción de tornillos de titanio por autorroscantes en el foramen menor que el núcleo del tornillo se acompaña de una proliferación ósea por osteogénesis de contacto mucho más modesta que en el caso de la inserción en el foramen mayor que el núcleo del tornillo.

Mucous non-goblet cells in the small intestine of guinea pigs (Cavia porcellus): a histological and histochemical study.

BACKGROUND: The covering and glandular epithelium of the small intestine in guinea pigs (Cavia porcellus) include some mucus-secreting cells. Goblet cells are specific cells for mucus secretion with a distinctive cup-like appearance due to the accumulation of mucin in the apical pole. The deep crypt secretory (DCS) cells were identified in a limited array of species and only recently were noticed in the large intestine in mice, guinea pigs, humans, monkeys, and pigs. Our study focuses on the microscopical and histochemical features of the DCS cells in the small intestine of guinea pigs. MATERIALS AND METHODS: The samples from the small intestine were collected from five fully grown guinea pigs that were presented to the Hospital of the Faculty of Veterinary Medicine Cluj-Napoca (Romania) with severe lesions resulted from domestic activities. The collected tissue samples underwent fixation in 10% buffered formalin and were later processed by standard paraffin technique. Mucous substances were detected using the Periodic Acid-Schiff and Alcian-Blue histochemical stain methods. RESULTS: The intestinal samples of the guinea pigs assessed had a standard microanatomical structure. As regards the mucous-secreting cells from the small intestine, two cell types were identified, i.e. the goblet cells and DCS cells. DCS cells were only detected in the deep parts of the Lieberkühn glands from the jejunum and ileum, and were different morphologically and histochemically from the regular goblet cells. CONCLUSIONS: Our study managed to describe for the first time in guinea pigs, the existence of DCS cells in the jejunum and ileum of the small intestine, but not in the duodenum.

Some segmental morphological and morphometrical features of the intima and media of the aortic wall in Chinchilla lanigera.

BACKGROUND: The aim of this study is to describe the morphology, morphometry and ultrastructure of segments of the thoracic and abdominal aorta portions in Chinchilla lanigera. Thickness measurements of the tunica intima and media complex of the aorta were taken. MATERIALS AND METHODS: In all observed specimens, the thickness values for the tunica intima and media complex of the cranial thoracic aorta were significantly higher (mean: 702.19 µm) when compared to the values of other analysed aortic segments (means: 354.18 µm; 243.55 µm). Complex statistical methods were used to assess the differences between various aortic segments. RESULTS AND CONCLUSIONS: The components of the vessel walls show variations in structure and thickness, presumably due to an adaptation to functional demand.

In vivo neutralization of TNF-alpha promotes humoral autoimmunity by preventing the induction of CTL.

Neutralization of TNF-alpha in humans with rheumatoid arthritis or Crohn's disease has been associated with the development of humoral autoimmunity. To determine the effect of TNF-alpha neutralization on cell-mediated and humoral-mediated responses, we administered anti-TNF-alpha mAb to mice undergoing acute graft-vs-host disease (GVHD) using the parent-into-F(1) model. In vivo neutralization of TNF-alpha blocked the lymphocytopenic features characteristic of acute GVHD and induced a lupus-like chronic GVHD phenotype (lymphoproliferation and autoantibody production). These effects resulted from complete inhibition of detectable antihost CTL activity and required the presence of anti-TNF-alpha mAb for the first 4 days after parental cell transfer, indicating that TNF-alpha plays a critical role in the induction of CTL. Moreover, an in vivo blockade of TNF-alpha preferentially inhibited the production of IFN-gamma and blocked IFN-gamma-dependent up-regulation of Fas; however, cytokines such as IL-10, IL-6, or IL-4 were not inhibited. These results suggest that a therapeutic TNF-alpha blockade may promote humoral autoimmunity by selectively inhibiting the induction of a CTL response that would normally suppress autoreactive B cells.

Clinical value of antineutrophil cytoplasmic antibodies.

This article presents a brief review of the clinical value of antineutrophil cytoplasmic antibodies (ANCA) in the diagnosis and management of patients with various forms of vasculitis. ANCA assay methodology and testing recommendations are reviewed. The patterns of reactivity of ANCA observed by indirect immunofluorescence, the antigens recognized by ANCA, and the sensitivity, specificity, and positive predictive value of ANCA for diagnosis of different vasculitides are described. In addition, the spectrum of drugs and nonvasculitic diseases that are associated with ANCA and need to be differentiated from true ANCA-positive vasculitides are reviewed. When properly utilized and cautiously interpreted, ANCA are a useful, noninvasive diagnostic tool in the differential diagnosis of vasculitis.

Differential effect of CTLA4Ig on murine graft-versus-host disease (GVHD) development: CTLA4Ig prevents both acute and chronic GVHD development but reverses only chronic GVHD.

The role of costimulation was examined in an in vivo model of alloantigen-driven Th1 or Th2 cytokine responses, the parent-into-F1 model of acute or chronic graft-vs-host disease (GVHD), respectively. The soluble fusion protein, murine CTLA4Ig, which blocks engagement of CD28 by its natural ligand B7-1 and B7-2, was administered either early, at the time of GVHD induction, or delayed, after the establishment of Th1 or Th2 effector responses (day 7). Early administration of CTLA4Ig prevented the development of both acute and chronic GVHD by preventing the activation of donor T cells, i.e., by blocking characteristic Th1 or Th2 cytokine production and blocking memory marker up-regulation on donor T cells. Delayed CTLA4Ig administration was unable to alter acute GVHD but did reverse chronic GVHD as evidenced by normalization of serum autoantibody levels, normal host B cell numbers and MHC class II expression, reduced donor T cell expression of CD40 ligand, and reduced numbers of donor CD4+ memory T cells. The percentage of donor memory cells was not altered by delayed CTLA4Ig. We conclude that in this model, alloantigen-driven Th1 or Th2 responses are equally susceptible to costimulatory blockade at the onset of disease; however, once effector mechanisms become established, only Th2-driven responses have a requirement for further costimulation for the continued expansion of CD4+ T cells. These data suggest that humoral, lupus-like autoimmunity requires continuous T cell help for B cells, and agents that interrupt this process may be beneficial.

Preliminary Studies of in vitro and in vivo Effects of Misoprostol on Th-1 and Th-2 Cytokine Production.

Prostaglandins of the E series are known to suppress in vitro production of Th-1 cytokines such as interleukin-2 (IL-2) and interferon-gamma but have not been shown to suppress production of Th-2 cytokines such as IL-4 or IL-10. The present study used two new synthetic prostaglandin E(1) (PGE(1)) analogs with oral bioavailability, misoprostol (MP), and enisoprost (EP), to determine if these agents (1) exert suppressive effects in vitro on cytokine production by fresh unseparated mouse splenocytes and (2) are beneficial in vivo when used in conditions mediated by excessive Th-1 or Th-2 cytokine production. Preliminary in vitro studies demonstrated that both MP and EP can inhibit mitogen-stimulated Th-1 and Th-2 cytokine production in a dose-dependent fashion. Interestingly, at low doses, a stimulatory effect on interferon-gamma production was seen for both agents. In vivo studies tested the ability of parenteral administration of MP to alter outcome in the parent-into-F1 model of acute or chronic graft-vs-host disease (GVHD), entities thought to be mediated by excessive Th-1 or Th-2 cytokine production, respectively. Administration of MP to mice undergoing acute GVHD resulted in little detectable effect. However, in three independent experiments, MP administration in chronic GVHD mice consistently blocked GVHD-associated lymphoproliferation. In two of three experiments, GVHD-associated autoantibody production was significantly reduced. Variability between individual mice and between experiments suggests that dosing regimens and MP preparation are of critical importance. Nevertheless, these findings raise the possibility that MP may be of benefit in the treatment of human diseases characterized by excessive Th-2 cytokine production and humoral autoimmunity, for example, human lupus.

Kinetics of Th1 and Th2 cytokine production during the early course of acute and chronic murine graft-versus-host disease. Regulatory role of donor CD8+ T cells.

Acute and chronic graft-versus-host disease (GVHD) in the parent-into-F1 model are mediated by predominantly cellular or humoral immune responses, respectively, and are strikingly different entities by 2 wk of disease. Both forms of GVHD, however, evolve from a common starting point, i.e., donor CD4+ T cell recognition of host alloantigen and IL-2 production. Our study examines the first 2 wk of GVHD to delineate the events that critically influence GVHD development. Surprisingly, both forms of GVHD are initially characterized by increased Th2 cytokine (IL-4 and IL-10) production and B cell activation which persists into wk 2. The earliest distinguishing features of acute GVHD were detectable at days 5 through 7 of disease and consisted of 1) expansion of donor CD8+ T cells, and 2) increased IFN-gamma production by donor CD4+ and CD8+ T cells. Interestingly, IFN-gamma production by donor CD4+ T cells was not seen if donor CD8+ T cells were not engrafted in comparable numbers. Chronic GVHD in the DBA-into-BDF1 model was found to be caused by a relative defect in the ability of DBA CD8+ T cells to induce acute GVHD and to produce IFN-gamma. These studies demonstrate that both acute and chronic GVHD begin as a Th2 cytokine-mediated, B cell stimulatory response. The transition to acute GVHD is critically dependent on the engraftment of donor CD8+ T cells, which terminate B cell hyperactivity by 1) eliminating activated B cells and 2) promoting IFN-gamma secretion by donor CD4+ T cells.

IL-12 stimulates the development of acute graft-versus-host disease in mice that normally would develop chronic, autoimmune graft-versus-host disease.

The injection of DBA/2 (D2) spleen cells into (C57BL/6 x DBA/2)F1 mice (BDF1) induces a chronic, autoimmune graft-vs-host disease (GVHD) that is characterized by: increased production of Th2-associated cytokines; increased levels of serum Ig, including IgE; increased production of IgG anti-DNA Abs; and no detectable antihost CTL activity. Experiments were performed to determine if treatment with the cytokine IL-12, which stimulates the production of Th1-associated cytokines and inhibits Th2-associated cytokine production, would inhibit humoral autoimmunity in this system. Treatment of mice with 100 ng IL-12 per day for 5 days, starting on the day of cell transfer, resulted in: 1) near complete suppression of autoantibody production; 2) decreased serum Ig levels; 3) detectable donor antihost CTL activity; and 4) greatly reduced numbers of host splenic B and T cells. Treatment of mice with a neutralizing anti-IFN-gamma mAb did not reverse these effects of IL-12. Thirty nanograms per day resulted in reduced numbers of host B cells and reduced serum anti-DNA levels, but no detectable antihost CTL activity. IL-12 treatment initiated 7 days after cell transfer had little effect on the development of autoimmune GVHD. These observations suggest the following: 1) IL-12 inhibits humoral autoimmunity in a murine parent-->F1 GVHD model by inducing the activation of host-reactive CTLs that reject the host immune system. 2) This effect is IFN-gamma-independent. 3) IL-12 needs to be present during the initial differentiation of T cells in this system to have this effect.

von Willebrand factor in synovial fluid.

Von Willebrand factor (vWf), an endothelial product that arises in plasma in conditions associated with vascular damage and acute phase reaction, was evaluated in paired samples of plasma and synovial fluid obtained from 54 patients with inflammatory joint effusion, 19 patients with osteoarthritis, and from the plasma of 19 controls. Synovial fluid levels of vWf were detected in 36 of the patients. The mean value of vWf in the inflammatory joint effusion group was 18.27 +/- 3.03%, significantly higher than the mean value of 7.7 +/- 4.4% found in the osteoarthritis group (p less than 0.01). The significant difference between these groups was maintained when vWf was expressed as a ratio of albumin. vWf was correlated with synovial fluid levels of alpha-1-antitrypsin (r = 0.83, p less than 0.01) and with the white cell count (r = 0.74, p less than 0.01), but not with the levels of immunoglobulins or C3. vWf in the synovial fluid may reflect the local degree of inflammation.

[The treatment of severe psoriatic arthritis with methotrexate in a weekly "mini-pulse" dosage plan]. / Tratamentul artritei psoriazice severe cu metotrexat în schema posologica "mini-pulse" saptamînal.

The paper reports on the authors' own experience on the effect of therapy with methotrexate (MTX) in 18 patients with invalidant psoriatic arthritis (PA). The therapeutic scheme was of the weekly "mini-pulse" type (three doses of 2.5 mg administered at 12-hour interval, with a gradual increase to 15 mg/week). The results were very good in 12 cases (66.6%), good in 3 cases (16.6%) and absent in other two cases (11.1%). These results and the data in the literature lead to the conclusion that MTX is a valuable therapeutic alternative for severe P.A. under the conditions of a correct surveillance with the observance of the contraindications.

Levels of SC5b--9 complement complex in plasma and synovial fluid of patients with rheumatic disease.

Activation of the terminal complement pathway leads to formation of the C5b--9 complex. The main effects of C5b--9 generation are tissue injury by cell lysis or by stimulation of proinflammatory mediators. In a study carried out in 42 patients, using polyclonal antibodies against C5b--9 neoantigens and C9 in an ELISA assay, we found significantly higher levels of SC5b--9 complex in plasma from the 18 patients with active systemic lupus erythematosus than those found in 10 healthy controls (p less than 0.005). In the 18 patients presenting rheumatoid arthritis and the 6 with progressive systemic sclerosis the plasma levels of SC5b--9 complex did not differ significantly from those in controls. The SC5b--9 levels found in the synovial fluid samples from the 16 rheumatoid arthritis patients were higher than the corresponding plasma ones. The ratio between synovial fluid and plasma levels was 1.2. Immunoperoxidase staining for C5b--9 was intense in three rheumatoid synovial membranes and absent in two normal synovial membranes obtained during meniscectomy. Increased levels of plasma and synovial fluid SC5b--9 reflect pathologic systemic or local activation of the complement carcase in systemic lupus erythematosus and respectively rheumatoid arthritis. Synovial membrane deposits of C5b--9 are indicative for the lytic and proinflammatory effects of complement activation.

von Willebrand factor in the plasma of patients with rheumatic diseases.

von Willebrand factor (vWf), an endothelial cell product, was evaluated in 39 patients with rheumatoid arthritis, 19 patients with connective tissue diseases and vasculitis, 21 patients with nonrheumatoid inflammatory arthritides, 14 patients with osteoarthritis and 19 controls. High plasma vWf levels were found in rheumatoid arthritis patients: 196.35 +/- 85.8 (p less than 0.001 versus control) connective tissue diseases and vasculitides: 306.50 +/- 43.4 (p less than 0.001 versus control) and inflammatory nonrheumatoid arthritides: 193.35 +/- 90.6 (p less than 0.01 versus control). Highly increased vWf concentrations of more than 300%, were found in one patient presenting Wegener granulomatosis, 6 patients with vasculitis associated to connective tissue diseases, 7 patients with rheumatoid arthritis and 2 patients with active forms of inflammatory arthritides. vWf was correlated with fibrinogen in the subgroup of systemic lupus erythematosus patients. Elevated vWf levels may reflect vascular damage as well as the acute phase reaction. Highly elevated levels of vWf appear to indicate a poor prognosis.

[HLA antigens and primary prolapse of the mitral valve]. / HLA antigény a primárny prolaps mitrálnej chlopne.

The authors present results of investigation of antigens of the HLA system in primary mitral valvular prolapse. The investigated group of patients was formed by 23 not related patients with primary mitral valvular prolapse. (15 women, 8 men, aged 18-55 years) where HLA antigens of loci A, B and C were assessed. They found a significantly increased frequency of antigen HLA-B35 in the patients (56.52%), as compared with the population (18.33%, x2 = 18.48, Pcorr less than 0.01). The measure of the observed relationship is expressed by the relative risk value--RR = 5.81. The difference in the frequency of the other HLA antigens was not statistically significant.

Joint hypermobility in primary mitral valve prolapse patients.

Twenty-seven patients with echocardiographic evidence of primary mitral valve prolapse (MVP) were tested for the presence of joint hypermobility using the criteria of Beighton and Horan. In the examined group, joint hypermobility was found in 14 patients (52%). This occurrence was statistically significant. In patients with simultaneous occurrence of MVP and articular hypermobility we have found a number of pathologic arthrologic manifestations, such as arthralgias, synovitic reactions, distortions, low back pain, and others. In patients with articular hypermobility, there were increased functions of antigen B 35.

Fibronectin in plasma and synovial fluid of patients with rheumatic diseases.

Fibronectin is a high molecular weight glycoprotein from plasma and other body fluids, connective tissue matrix and basement membranes. No significant differences in the mean values of plasma fibronectin were found in patients with rheumatic diseases compared to control subjects. The fibronectin in synovial fluids in these patients presented higher levels than in plasma. No other protein from the synovial fluid presented such a peculiar behaviour. The synovial fluid fibronectin/plasma fibronectin ratio is 2.49 in patients with rheumatoid arthritis, 1.56 in those with inflammatory nonrheumatoid arthritides and 1.60 in those with osteoarthritis. Statistically significant higher values of synovial fibronectin were found in patients with rheumatoid arthritis compared to those with osteoarthritis. No significant statistical correlations were found between the synovial fibronectin concentrations and the other clinical or biological parameters of the rheumatoid arthritis patients, but for synovial fluid C3. Immunohistochemical localization of fibronectin in the rheumatoid synovium showed more intense and extended specific deposits than in the control patients. These results suggest a local synthesis of fibronectin related to the chronic inflammatory process.

Efficiency of utilisations of food energy by female growing minks.

The efficiency of utilisation of food energy by female growing minks, from weaning to adult age, was studied. The food given, pelleted according to an original technology, has the following chemical composition on a DM basis: 87.0% organic matter, 37.1% crude protein, 11.7% crude fat, 2.6% crude fiber, 35.6% nitrogen-free extractives and 13.0 per cent ash. Young minks had a feed intake, in relation to body weight, warying from 11.6 g to 58.6 g DM/d. Maximum feed intake related to kg0.75 was recorded at 700 g body weight (approximately 98 g DM/kg0.65). Digestibility of the given food expressed in DE, averaged 87.7 +/- 1.2%, while metabolizability, 82.3 +/- 1.1%. Total heat production related to the intaked gross energy, was 48.0 +/- 3.0%, and the retained energy, 34.3 +/- 4.0 per cent. The net efficiency of the metabolizable energy used for maintenance and production could not be accurately determined. However, taking to account the calculated values required for maintenance, of 649 kJ/kg0.75 in 300 to 600 g young minks, and of 607 kJ/kg0.75 in 600 to 1100 g young minks and also the maintenance efficiency, Km = 0.75, the coefficient for ME utilisation in protein and fat synthesis, of 0.50 and 0.75, respectively, it was able to determine the average ME efficiency used as net energy for maintenance and production: 70%. The highest values of nictemeral metabolism were recorded in the evening, and the lowest ones, at noon; the difference between the maximal and the minimal value did not exceed 6 per cent.

[Feed conversion and the energy requirement of pregnant heifers]. / Die Verwertung des Futters und der Energiebedarf trächtiger Färsen.

Eight Holstein heifers were subjected to experiments running over the entire pregnancy period to investigate the conversion of rations mainly made up of maize silage (85% of the ration's dry matter) by the experimental animals. Both digestible and metabolizable energy (ME) and the energy requirement were studied. The live weight (LW) of the heifers was found to rise linearly during the entire pregnancy period being 422 kg at service and reaching 565 kg at calving. Feed intake, referred to 1 kg live weight0.75, was almost constant until the 7th month of gestation and declined gradually until parturition. The degree of digestibility and metabolizability of the energy contained in the silage-bases rations prove equal over the whole gestation period. The energy required for maintenance and gravidity (y) was found to rise exponentially as pregnancy advance (t). This relationship is reflected by the equation: ME, kcal/kg LW0.75y=135+0.2590.0206t range of significance=+/-0.07 During the last two months of gestation, a negative energy balance was found. This negative energy balance corresponds with a negative fat balance and a reduction, of the respiratory quotient, a fact suggesting to the mobilisation of body fat reserves by the mother to cover the increased energy requirement during pregnancy. The protein balance was found continuously positive during the entire gestation period. The conversion of metabolizable energy for fetus development was found to be 8.13%.