Low cellular IRS 1 gene and protein expression predict insulin resistance and NIDDM

We examined the gene and protein expression of IRS 1 (insulin receptor substrate 1) in adipocytes from two groups of healthy individuals with an increased propensity for non-insulin-dependent diabetes mellitus (NIDDM): those with two first-degree relatives with diabetes and another group with massive obesity. A low expression of IRS 1 (</=50% of the matched control group) was seen in approximately 30% of both groups and these individuals were characterized by insulin resistance and its hallmarks: higher levels of insulin, glucose, and triglycerides. Two individuals with previously unknown NIDDM were diagnosed and both had low IRS 1 expression. Low IRS 1 protein expression was associated with low mRNA levels but not with the common Gly972Arg polymorphism of the IRS 1 gene. Taken together, our present and previous findings show that a low expression of IRS 1 in fat cells predicts insulin resistance and NIDDM. Furthermore, they support the likelihood that an impaired transcriptional activation may play a key role in the pathogenesis of NIDDM.-Carvalho, E., Jansson, P.-A., Axelsen, M., Eriksson, J. W., Huang, X., Groop, L., Rondinone, C., Sjöström, L., Smith, U. Low cellular IRS 1 gene and protein expression predict insulin resistance and NIDDM.

Flow cytometric determination of cellular sources and frequencies of key cytokine-producing lymphocytes directed against recombinant LACK and soluble Leishmania antigen in human cutaneous leishmaniasis

Leishmaniasis, caused by infection with the protozoan parasite Leishmania, affects millions of individuals worldwide, causing serious morbidity and mortality. This study directly determined the frequency of cells producing key immunoregulatory cytokines in response to the recombinant antigen Leishmania homolog of receptors for activated kinase C (LACK) and soluble leishmania antigen (SLA), and it determined relative contributions of these antigens to the overall cytokine profile in individuals infected for the first time with Leishmania braziliensis. All individuals presented with the cutaneous clinical form of leishmaniasis and were analyzed for proliferative responses to LACK antigen and SLA, frequency of lymphocyte subpopulations (analyzed ex vivo), and antigen-induced (LACK and SLA) cytokine production at the single-cell level (determined by flow cytometry). The following were determined. (i) The Th1-type response previously seen in patients with cutaneous leishmaniasis is due to gamma interferon (IFN-gamma) production by several different sources, listed in order of contribution: CD4(+) T lymphocytes, CD4(-), CD8(-) lymphocytes, and CD8(+) T lymphocytes. (ii) SLA induced a higher frequency of lymphocytes producing IFN-gamma and tumor necrosis factor alpha (TNF-alpha) than did LACK. (iii) LACK induced an activation of monocyte populations as reflected by an increased percentage of CD14-positive cells. (iv) Neither SLA nor LACK induced detectable frequencies of cells producing interleukin-4 (IL-4) or IL-5. These data demonstrated a multifaceted immune response to SLA in human leishmaniasis involving Th1 CD4(+) T lymphocytes (IFN-gamma(+) and IL-10(-)/IL-4(-)), Tc1 CD8(+) T cells (IFN-gamma(+), and IL-10(-)/IL-4(-)), and a high frequency of TNF-alpha-producing lymphocytes. Moreover, it was determined that the recombinant antigen LACK acts as a weak inducer of Th1-type lymphocyte responses compared to SLA.

The value of an immunoenzymatic test (enzyme-linked immunosorbent assay) for the diagnosis of strongyloidiasis in patients immunosuppressed by hematologic malignancies

The diagnosis of strongyloidiasis relies upon the identification of the parasite in stool samples. In 1981, a serologic assay was developed, which was useful in the diagnosis of strongyloidiasis in the immunocompetent host. In the present study, we evaluated the enzyme-linked immunosorbent assay (ELISA) in patients with hematologic malignancies. Between April 1995 and December 1998, sera from 164 consecutive patients were tested for the presence of IgG antibody to Strongyloides stercoralis. Patient was considered uninfected after at least three negative stool examinations. The prevalence of strongyloidiasis was 13%. The underlying diseases were acute leukemia in 21% and lymphoma in 52% of the patients. The majority of the patients were receiving chemotherapy (93%) and steroids (76%). The sensitivity, specificity, and positive and negative predictive values were 68%, 89%, 48%, and 95%, respectively. The ELISA may be an excellent assay to rule out the diagnosis of strongyloidiasis in patients with hematologic malignancies.

Insulin signaling and action in fat cells: associations with insulin resistance and type 2 diabetes

Adipose tissue only accounts for a relatively small proportion (< 10%) of the peripheral glucose utilization in response to insulin. However, the fat cells may still play an important role in insulin resistance and Syndrome X through, for instance, its endocrine functions (production of leptin, TNF alpha, PAI-1, etc.) and involvement in lipid metabolism (FFA release and hydrolysis of triglycerides). The fat cells are also highly sensitive to insulin and may thus be used to elucidate molecular mechanisms for insulin resistance in man. Examinations of the intracellular signaling mechanisms for insulin in fat cells from individuals with Type 2 diabetes revealed markedly lower insulin-stimulated PI3-kinase activity. This was due to a pronounced reduction in the cellular expression of the docking protein, IRS 1, whereas expression of IRS 2 was normal. However, IRS 2-associated PI3-kinase activity was only approximately one-third of that found to be associated with IRS 1 in normal cells. Downstream activation and serine phosphorylation of PKB/Akt by insulin were also markedly reduced in Type 2 diabetes. Furthermore, the dose-response curve for this effect of insulin was similar to that for glucose transport in both normal and Type 2 diabetic cells. Thus, these data show that both PI3-kinase and PKB activation by insulin are markedly reduced in Type 2 diabetes. We also examined whether an attenuated activation of PI3-kinase by insulin can be seen in non-diabetic insulin-resistant states. Approximately 30% of healthy subjects with at least two first-degree relatives with Type 2 diabetes exhibited perturbations in IRS-1 expression and signaling. These individuals were characterized by insulin resistance as well as other markers of Syndrome X. Thus, impaired IRS-1 expression and downstream signaling events in fat cells in response to insulin are associated with insulin resistance and Syndrome X.

Immune aging in diabetes and its implications in wound healing

Immune systems have evolved to recognize and eliminate pathogens and damaged cells. In humans, it is estimated to recognize 109 epitopes and natural selection ensures that clonally expanded cells replace unstimulated cells and overall immune cell numbers remain stationary. But, with age, it faces continuous repertoire restriction and concomitant accumulation of primed cells. Changes shaping the aging immune system have bitter consequences because, as inflammatory responses gain intensity and duration, tissue-damaging immunity and inflammatory disease arise. During inflammation, the glycolytic flux cannot cope with increasing ATP demands, limiting the immune response's extent. In diabetes, higher glucose availability stretches the glycolytic limit, dysregulating proteostasis and increasing T-cell expansion. Long-term hyperglycemia exerts an accumulating effect, leading to higher inflammatory cytokine levels and increased cytotoxic mediator secretion upon infection, a phenomenon known as diabetic chronic inflammation. Here we review the etiology of diabetic chronic inflammation and its consequences on wound healing.

Phosphorylation of PDE3B by phosphatidylinositol 3-kinase associated with the insulin receptor

Phosphatidylinositol 3-kinase mediates several actions of insulin including its antilipolytic effect. This effect is elicited by the insulin-stimulated serine phosphorylation and activation of cGMP-inhibited phosphodiesterase (PDE3B). In human adipocytes, we found that insulin differentially stimulated phosphatidylinositol 3-kinase activity; the lipid kinase activity was associated with IRS-1, whereas the serine kinase activity was associated with the insulin receptor and phosphorylated a number of proteins including p85, p110, and a 135-kDa protein identified as PDE3B. PDE3B phosphorylation was associated with enzyme activation, thus initiating the antilipolytic effect of insulin. These results show a novel pathway for intracellular signaling through the insulin receptor leading to the serine phosphorylation of key proteins involved in insulin action.

Impaired glucose transport and protein kinase B activation by insulin, but not okadaic acid, in adipocytes from subjects with Type II diabetes mellitus

AIMS/HYPOTHESIS

To study the effects of insulin and okadaic acid, a serine/threonine phosphatase inhibitor which does not increase PI3-kinase activity, on the rate of glucose transport and protein kinase B activation in adipocytes from healthy subjects and subjects with Type II (non-insulin-dependent) diabetes mellitus.

METHODS

Adipocytes were incubated with or without insulin or okadaic acid or both and glucose transport, protein kinase B activity, phosphorylation and protein expression measured.

RESULTS

Insulin and okadaic acid alone increased glucose uptake to a similar degree in adipocytes from healthy subjects and, when combined, exerted a partial additive effect. The effect of insulin was reduced by about 60% in adipocytes from Type II diabetic patients, whereas the effect of okadaic acid was essentially unchanged and no further increase was seen when okadaic acid and insulin were combined. Okadaic acid increased protein kinase B activity to a greater extent (two to threefold) than insulin but only slightly increased the serine phosphorylation of protein kinase B. Adipocytes from Type II diabetic subjects exhibited both an impaired sensitivity as well as a reduced total serine phosphorylation and activation of protein kinase B in response to insulin but protein kinase B activity in response to okadaic acid was intact.

CONCLUSION/INTERPRETATION

These results show that the ability of insulin to increase glucose transport and activate protein kinase B is reduced in fat cells from Type II diabetic subjects. Protein kinase B can, however, be activated by agents like okadaic acid which bypass the upstream defects in the insulin signalling pathway in Type II diabetic cells and, thus, increase glucose uptake.

Insulin resistance in fat cells from obese Zucker rats--evidence for an impaired activation and translocation of protein kinase B and glucose transporter 4

The effect of insulin on glucose transport, glucose transporter 4 (Glut4) translocation, and intracellular signaling were measured in fat cells from lean and obese Zucker rats of different ages. Insulin-stimulated glucose transport was markedly reduced in adipocytes from old and obese animals. The protein content of Glut4 and insulin receptor substrates (IRS) 1 and 2 were also reduced while other proteins, including the p85 subunit of PI3-kinase, Shc and the MAP kinases (ERK1 and 2) were essentially unchanged. There was a marked impairment in the insulin stimulated tyrosine phosphorylation of IRS-1 and 2 as well as activation of PI3-kinase and PKB in cells from old and obese animals. Furthermore, insulin-stimulated translocation of both Glut4 and PKB to the plasma membrane was virtually abolished. The phosphotyrosine phosphatase inhibitor, vanadate, increased the insulin-stimulated upstream signaling including PI3-kinase and PKB activities as well as rate of glucose transport. Thus, the insulin resistance in cells from old and obese Zucker rats can be accounted for by an impaired translocation process, due to signaling defects leading to a reduced activation of PI3-kinase and PKB, as well as an attenuated Glut4 protein content.

Biological activity of region 65-102 of the myelin basic protein

Region 65-102 of the myelin basic protein (MBP) houses a number of antigenic determinants known to induce delayed-type hypersensitivity, experimental allergic encephalomyelitis (EAE), suppressor cell function, and antibodies. In this report we describe the biological activity of synthetic peptides S53, S55, and S49 with sequence homology to region 69-84 of the rat, guinea pig, and bovine MBP. Peptide S53-A, defined by residues 75-84 of the guinea pig (SQRSQDEN) and of the rat (SQRTQDEN) MBP induced clinical signs of disease in Lewis rats. These included weight loss, flaccid tail, "muscle wasting," and hind-leg weakness. Histological examination of brain, spinal cord, and sciatic nerve sections of diseased rats revealed the complete absence of focal and perivascular lymphocytic infiltrates characteristics of demyelinating EAE lesions. Elongation of peptide S53 by three or six residues to residue sequences naturally found at its N-terminal end gave rise to peptides S55S (PQKSQRSQDEN) and S49S (GSLPQKSQRSDQDEN), respectively. Lewis rats challenged with either S55S or S49S developed classical clinical and histological signs of EAE. Severe hind-leg paralysis was accompanied by incontinence and sometimes death. Injected in the form of carrier-free peptide, S53 was a meager B cell immunogen. S53 conjugated with methylated-bovine serum albumin was also a potent immunogen and produced clinical signs of disease without CNS pathology. By comparison, carrier-free S55S and S49S were potent immunogens giving rise to antibodies that cross reacted completely and competitively with S55S but considerably less so with S53. The results show that the sequence of S53 defines an epitope responsible for the formation of anti-S53 antibodies. Elongation of the S53 sequence at its N-terminal end generated an additional epitope which induced cell-mediated immunity responsible for the concomitant development of pathological signs of EAE. It may be concluded that the induction of classical signs of EAE requires specific and defined sequences capable of expressing both B cell and T cell functions.

PKB inhibition prevents the stimulatory effect of insulin on glucose transport and protein translocation but not the antilipolytic effect in rat adipocytes

We identified 1-(5 chloronaphthalenesulfonyl)-1H-hexahydro-1, 4-diazepine, also known as ML-9, as a powerful inhibitor of PKB activity in different cells as well as of recombinant PKB. It also inhibits other downstream serine/threonine kinases, such as PKA and p90 S6 kinase, but not upstream tyrosine phosphorylation or PI3-kinase activation in response to insulin. We compared the effects of ML-9 and wortmannin on several insulin-stimulated effects in isolated rat fat cells. Both ML-9 and wortmannin inhibited glucose transport and GLUT4/IGF II receptor translocation to the plasma membrane. In contrast, only wortmannin inhibited the antilipolytic effect and PDE3B activation by insulin. Thus, ML-9 inhibits PKB but not PI3-kinase activation in response to insulin and is useful to differentiate between these effects. Both PI3-kinase and PKB are important for glucose transport and intracellular protein translocation while PKB does not appear to play an important role for the antilipolytic effect or activation of PDE3B in response to insulin.

Establishment and characterization of immortalized clonal cell lines from fetal rat mesencephalic tissue

This investigation reports for the first time the establishment of immortalized clones of dopamine-producing nerve cells in culture. Freshly prepared single-cell suspensions from fetal (12-day-old) rat mesencephalic tissue were transfected with plasmid vectors, pSV3neo and pSV5neo, using an electroporation technique. Cells were plated in tissue culture dishes which were precoated with a special substrate and contained modified MCDB-153 growth medium with 10% heat inactivated fetal bovine serum. The immortalized cells were selected by placing the transfected cells in a selection medium (modified MCDB-153 containing 400 micrograms/ml geneticin). The survivors showed the presence of T-antigens and were non-tumorigenic. Two cell lines, 1RB3 derived from cells transfected with pSV3neo, and 2RB5 derived from cells transfected with pSV5neo revealed only 1 to 2% tyrosine hydroxylase (TH)-positive cells. Repeated single-cell cloning of these cell lines by a standard technique failed to increase the number of TH-positive cells in any clones. Using three cycles of growth, alternating between hormone-supplemented, serum-free medium and serum-containing medium produced a cell line (1RB3A) that was very rich in TH-positive cells. The recloning of 1RB3A yielded clones some of which contained over 95% TH-positive cells. These cells produced homovanillic acid, a metabolite of dopamine, and may be useful not only for neural transplant but also for basic neurobiological studies.

Impaired phosphorylation and insulin-stimulated translocation to the plasma membrane of protein kinase B/Akt in adipocytes from Type II diabetic subjects

AIMS/HYPOTHESIS

To examine protein kinase B/Akt distribution and phosphorylation in response to insulin in different subcellular fractions of human fat cells from healthy subjects and subjects with Type II (non-insulin-dependent) diabetes mellitus.

METHODS

We prepared subcellular fractions of plasma membranes (PM), low density microsomes and cytosol and examined gene and protein expression as well as serine and threonine phosphorylation in response to insulin.

RESULTS

Protein kinase B/Akt mRNA as well as total protein kinase B/Akt protein in whole-cell lysate and cytosol were similar in both groups. Insulin increased protein kinase B/Akt translocation to the the plasma membrane about twofold [(p < 0.03) in non-diabetic cells but this effect was impaired in diabetic cells (approximately 30%; p > 0.1)]. In both groups, protein kinase B/Akt threonine phosphorylation considerably increased in low density microsomes and cytosol whereas serine phosphorylation was predominant in the plasma membrane. Phosphatidylinositol-dependent kinase 1, which partially activates and phosphorylates protein kinase B/Akt on the specific threonine site, was predominant in cytosol but it was also recovered in low density microsomes. Serine phosphorylation in response to insulin was considerably reduced (50-70 %; p < 0.05) in diabetic cells but threonine phosphorylation was less reduced (approximately 20%). Wortmannin inhibited these effects of insulin supporting a role for PI3-kinase activation.

CONCLUSION/INTERPRETATION

Insulin stimulates a differential subcellular pattern of phosphorylation of protein kinase B/Akt. Furthermore, insulin-stimulated translocation of protein kinase B/Akt to the plasma membrane, where serine phosphorylation and full activation occurs, is impaired in Type II diabetes. Threonine phosphorylation was much less reduced. This discrepancy may be related to differential activation of phosphatidylinositol 3-kinase in the different subcellular compartments and phosphatidylinositol-dependent kinase 1 having high affinity for phosphatidylinositol phosphate 3.

Molecular and cellular mechanisms of bone morphogenetic proteins and activins in the skin: potential benefits for wound healing

Bone morphogenetic proteins (BMPs) and activins are phylogenetically conserved proteins, belonging to the transforming growth factor-β superfamily, that signal through the phosphorylation of receptor-regulated Smad proteins, activating different cell responses. They are involved in various steps of skin morphogenesis and wound repair, as can be evidenced by the fact that their expression is increased in skin injuries. BMPs play not only a role in bone regeneration but are also involved in cartilage, tendon-like tissue and epithelial regeneration, maintain vascular integrity, capillary sprouting, proliferation/migration of endothelial cells and angiogenesis, promote neuron and dendrite formation, alter neuropeptide levels and are involved in immune response modulation, at least in animal models. On the other hand, activins are involved in wound repair through the regulation of skin and immune cell migration and differentiation, re-epithelialization and granulation tissue formation, and also promote the expression of collagens by fibroblasts and modulate scar formation. This review aims at enunciating the effects of BMPs and activins in the skin, namely in skin development, as well as in crucial phases of skin wound healing, such as inflammation, angiogenesis and repair, and will focus on the effects of these proteins on skin cells and their signaling pathways, exploring the potential therapeutic approach of the application of BMP-2, BMP-6 and activin A in chronic wounds, particularly diabetic foot ulcerations.

Modification of the expression of adenosine 3',5'-cyclic monophosphate-induced differentiated functions in neuroblastoma cells by beta-carotene and D-alpha-tocopheryl succinate

OBJECTIVE

The role of beta-carotene and vitamin E in modifying the effect of cell differentiating agent has not been studied. This study has investigated the effects of beta-carotene and d-alpha-tocopheryl succinate (alpha-TS) on adenosine 3',5'-cyclic monophosphate (cAMP) induced differentiated functions in murine neuroblastoma cells (NBP2) in culture.

METHODS

Prostaglandin E1 (PGE1), a stimulator of adenylate cyclase, and 4-(3-butoxy-4-methoxy-benzyl)-2-imidazolidinone (R020-1724), an inhibitor of cyclic nucleotide phosphodiesterase, were used to induce differentiation in NB cells.

RESULTS

Both beta-carotene and alpha-TS markedly enhanced the level of morphologic differentiation (neurite formation) induced by both PGE1 and R020-1724. However, beta-carotene and alpha-TS by themselves were ineffective. These vitamins increased tyrosine hydroxylase (TH) activity. However, beta-carotene did not significantly affect PGE1- and R020-1724-stimulated rise in TH activity. alpha-TS at a higher concentration inhibited PGE1- and R020-1724-stimulated increase in TH activity. None of the above treatments affected basal choline acetyltransferase (ChAT) activity. beta-carotene and alpha-TS caused a transient increase in cAMP level, and they also enhanced the effect of PGE1 and R020-1724 on cAMP level in a transient manner.

CONCLUSION

These results suggest that beta-carotene and alpha-TS modify the effects of cAMP stimulating agents on differentiation of NB cells in culture.

Triazene drug metabolites. Part 17: Synthesis and plasma hydrolysis of acyloxymethyl carbamate derivatives of antitumour triazenes

A series of 3-acyloxymethyloxycarbonyl-1-aryl-3-methyltriazenes 5 was synthesised by the sequential reaction of 1-aryl-3-methyltriazenes with (i) chloromethyl chloroformate, (ii) NaI in dry acetone, and (iii) either the silver carboxylate or the carboxylic acids in the presence of silver carbonate. The hydrolysis of these compounds was studied in pH 7.7 isotonic phosphate buffer and in human plasma. Triazene acyloxycarbamates demonstrated their ability to act as substrates for plasma enzymes. For compound 5f, a pH-rate profile was obtained which showed the hydrolysis to involve acid-base catalysis. The reaction is also buffer catalysed. Thus, at pH 7.7, pH-independent, base-catalysed and buffer-catalysed processes all contribute to the hydrolysis reaction. The sensitivity of the hydrolysis reaction to various structural parameters in the substrates indicates that hydrolysis occurs at the ester rather than the carbamate functionality. In plasma, the rates of hydrolysis correlate with partition coefficients, the most lipophilic compounds being the most stable. An aspirin derivative suffers two consecutive enzymatic reactions, the scission of the aspirin acetyl group being followed by the scission of the acyloxy ester group. These results indicate that triazene acyloxymethyl carbamates are prodrugs of the antitumour monomethyltriazenes. They combine chemical stability with a rapid enzymatic hydrolysis, and are consequently good candidates for further prodrug development. Moreover, this type of derivative allowed the synthesis of mutual prodrugs, associating the antitumour monomethyltriazenes with anti-inflammatory NSAIDs as well as with the anticancer agent butyric acid.

Erectile dysfunction and HTLV-I infection: a silent problem

The human T-lymphotropic virus type I (HTLV-I) is a retrovirus associated with a chronic myelopathy known as HTLV-I-Associated Myelopathy or Tropical Spastic Paraparesis (HAM/TSP). The main objective was to assess the frequency of erectile dysfunction (ED) in HTLV-I-infected individuals from Salvador and other cities from Bahia, Brazil, as well as to verify if sexual dysfunction correlates with urinary symptoms and overall neurological impairment. From January 2001 to April 2004, 218 HTLV-I carriers (111 male and 107 female subjects) had complete clinical, neurological, and urological evaluation. They were assessed using standardized questionnaires to determine urinary complaints (Urinary Distress Inventory) and ED (Brief Male Sexual Function Inventory). Neurological impairment was established by Expanded Disability Status Scale (EDSS) from 0 to 10. HAM/TSP was considered as EDSS> or =2. A total of 17 males had clinically defined HAM/TSP (group 1). From the 94 HTLV-I-infected males, 62 were selected (group 2) and paired by age with patients in group 1. A total of 79 individuals were selected for this study. The age ranged from 35 to 81 y (mean=47.9+/-9.65). The percentage of ED in the studied population was 40.5%. In the HAM/TSP group, ED frequency was 88.2%. The associations among sexual dissatisfaction, erectile dysfunction, urinary symptoms (frequency, nocturia, and urgency) and EDSS> or =2 were statistically significant. In HAM/TSP, there is a slow and progressive degeneration of the lateral funiculus of the spinal cord. HTLV-I-infected individuals present a high frequency of ED and it is closely associated to urinary symptoms and the overall neurological picture. The HTLV-I carriers already had prominent compromise of the sexual activity.

Trends in adjuvant development for vaccines: DAMPs and PAMPs as potential new adjuvants

Aluminum salts have been widely used in vaccine formulations and, after their introduction more than 80 years ago, only few vaccine formulations using new adjuvants were developed in the last two decades. Recent advances in the understanding of how innate mechanisms influence the adaptive immunity opened up the possibility for the development of new adjuvants in a more rational design. The purpose of this review is to discuss the recent advances in this field regarding the attempts to determine the molecular basis and the general mechanisms underlying the development of new adjuvants, with particular emphasis on the activation of receptors of innate immune recognition. One can anticipate that the use of these novel adjuvants will also provide a window of opportunities for the development of new vaccines.

Inflammatory macrophages in the dog contain high amounts of intravesicular ferritin and are associated with pouches of connective tissue fibers

We have studied the subcellular distribution of ferritin in inflammatory macrophages present in regional lymph nodes from dogs subjected to a pulmonary inflammatory reaction. The inflammatory reaction was induced by intrabronchial instillation of calcium tungstate (CaWO4), a water-insoluble powder. Ferritin was identified by electron microscopy, and its electron density was enhanced by the use of a modified Perls method. From day 14 on after the CaWO4 deposition, tungsten-positive lymph node macrophages showed a massive accumulation of ferritin. Most of the ferritin was stored in membrane-bounded vesicles that showed heterogeneous concentrations of the protein. A significant complement of ferritin was also detected in the cytoplasmic ground substance of phagocytes. The cell surface of the ferritin-rich, tungsten-positive macrophages showed deep infoldings that encompassed small pockets of connective tissue fibers. These features were not observed in control samples or in lymph nodes from dogs subjected to CaWO4-induced inflammation for periods shorter than 1 week. Our data indicate that inflammatory macrophages greatly increase their content of ferritin macrophages greatly increased their content of ferritin and that ferritin is stored predominantly by a membrane-bounded vesicular compartment. This is in contrast with suggestions that the inflammation-induced increase in macrophage iron is restricted to the labile pool of iron and it does not involve the iron bound to ferritin molecules. Our observation of nodules of connective-tissue fibers in intimate topographical association with ferritin-rich macrophages may indicate that the increase in intracellular ferritin in the macrophage is in some way related to the secretion of factors by the phagocyte that will stimulate fibrillogenesis by neighboring fibroblats.

The effect of a passive muscle stretching protocol on the articular cartilage

OBJECTIVE

The aim of this study is to evaluate the articular cartilage alterations of rat ankles, after applying unilateral cyclic passive muscle stretching protocol in previously immobilized rats.

METHODS

Twenty-two male albino rats divided into four groups, I--immobilized; IS--immobilized and stretched; S--stretched and C--control, were used in this experiment. The I and IS groups were immobilized for 4 weeks. In the muscle stretching protocol the treated ankle joint (groups IS and S) was manually full dorsal flexed 10 times for 60s with a 30s interval between each 60s period, 7 days a week for 3 weeks, to stretch the ankle plantar flexors muscle group. The right hind limb was free to move. At the end of the experiment, the ankles were removed, processed in paraffin and stained with hematoxylin-eosin and Safranin-O. Two blinded observers evaluated cellularity, chondrocyte cloning and Safranin-O staining through light microscopy. And a morphometric study was carried out using a hand count of chondrocyte cells and cartilage thickness measurement.

RESULTS

No significant effect of solely muscle stretching concerning cellularity, chondrocyte cloning and Safranin-O staining parameters was detected. However, IS group presented a significantly higher reduction of proteoglycans content than the solely stretched and solely immobilized groups and the morphometric analysis showed significant cellularity increase without thickness alteration compared to control.

CONCLUSIONS

These findings suggest that the stretching protocol used was harmful to the previously immobilized articular cartilage. However, the same stretching protocol did not harm the cartilage of non-immobilized groups.

Environmental contamination by Toxocara sp eggs in public areas of Salvador, Bahia State, Brazil

A survey of parasite eggs and cysts in soil and dog feces collected in public places of 23 boroughs of Salvador, a city in the Northeast of Brazil, was performed. High degree of contamination by Toxocara sp eggs was observed in all boroughs studied; other parasites found included: Ascaris lumbricoides, hookworms, whipworms and protozoan cysts. Parks and public gardens were more contaminated than streets and beaches for all parasites, including Toxocara sp.