Renal concentration of alpha-tocopherol: dependence on gender and lack of effect on polycystic kidney disease in Han:SPRD rats

A gender-associated dimorphism, with males being more severely affected than females, has been observed in autosomal dominant polycystic kidney disease, acquired renal cystic disease, and the renal cystic disease of the Han:SPRD rat. A recent study has suggested that gonadal hormones may be responsible for this dimorphism. Because gonadal hormones have an effect on the concentration of alpha-tocopherol in the liver and adrenal glands and because recent studies indicate that oxidative stress may be important in the pathogenesis of polycystic kidney disease, we wanted to determine whether the renal concentration of alpha-tocopherol is higher in female than in male rats and whether this difference accounts for the gender dimorphism of polycystic kidney disease in Han:SPRD rats. At 3 weeks of age, male and female heterozygous cystic (cy/+) rats were divided into three groups fed a vitamin E-deficient diet or the same diet supplemented with either 65 IU or 10,000 IU alpha-tocopherol/kg laboratory chow. At 8 weeks of age, blood samples and kidneys were obtained for determinations of plasma creatinine and urea, renal concentration of alpha-tocopherol and glutathione, kidney weights, and histomorphometric analysis. Female rats had higher renal concentrations of alpha-tocopherol and less severe renal cystic disease, as reflected by plasma creatinine and urea values, kidney weight corrected by body weight, and histomorphometric analysis, than male rats. The difference in renal alpha-tocopherol concentration, however, could not account for the different severity of the renal cystic disease, because depletion or enrichment of vitamin E in the diet had marked effects on the renal concentration of alpha-tocopherol without affecting the severity of the renal cystic disease. Cy/+ rats had higher renal concentrations of alpha-tocopherol than +/+ animals, possibly reflecting a disturbance of redox metabolism associated with polycystic kidney disease. Renal concentrations of glutathione were unaffected by the vitamin E content of the diet. Although these results do not support the use of vitamin E in the treatment of polycystic kidney disease, observations in the Han:SPRD rat may or may not be relevant to human polycystic kidney disease.     

Evaluating a Mental Health Program for Palestinian Refugees in Lebanon

Medecins sans Frontière, an international non-governmental organization, initiated a mental health program for Palestinian refugees living in Lebanon. To evaluate the impact of the program after its completion, focus groups were conducted with three target groups: (1) patients, (2) staff, and (3) local community stakeholders. Participants voiced overall satisfaction with the program. The program provided easy access, good quality care, decreased stigma, as perceived by participants, and revealed a sense of community contentedness. In addition, several short-term outcomes were achieved, such as increasing the numbers of patients visiting the center/ receiving mental health treatment. However, lack of planning for sustainability and proper procedures for hand-over of the program constituted a major downfall. Program discontinuation posed ethical dilemmas, common in provisional interventions in underprivileged refugee communities.     

Stromal cells from human long-term marrow cultures are mesenchymal cells that differentiate following a vascular smooth muscle differentiation pathway

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle- specific actin isoforms. The present study was carried out to evaluate the time course of alpha-SM-positive stromal cells and to search for other cytoskeletal proteins specific for smooth muscle cells. It was found that the expression of alpha-SM in stromal cells was time dependent. Most of the adherent spindle-shaped, vimentin-positive stromal cells observed during the first 2 weeks of culture were alpha- SM negative. On the contrary, from week 3 to week 7, most interdigitated stromal cells contained stress fibers whose backbone was made of alpha-SM-positive microfilaments. In addition, in confluent cultures, other proteins specific for smooth muscle were detected: metavinculin, h-caldesmon, smooth muscle myosin heavy chains, and calponin. This study confirms the similarity between stromal cells and smooth muscle cells. Moreover, our results reveal that cells in vivo with the phenotype closest to that of stromal cells are immature fetal smooth muscle cells and subendothelial intimal smooth muscle cells; a cell subset with limited development following birth but extensively recruited in atherosclerotic lesions. Stromal cells very probably derive from mesenchymal cells that differentiate along this distinctive vascular smooth muscle cell pathway. In humans, this differentiation seems crucial for the maintenance of granulomonopoiesis. These in vitro studies were completed by examination of trephine bone marrow biopsies from adults without hematologic abnormalities. These studies revealed the presence of alpha-SM-positive cells at diverse locations: vascular smooth muscle cells in the media of arteries and arterioles, pericytes lining capillaries, myoid cells lining sinuses at the abluminal side of endothelial cells or found within the hematopoietic logettes, and endosteal cells lining bone trabeculae. More or less mature cells of the granulocytic series were in intimate contact with the thin cytoplasmic extensions of myoid cells. Myoid cells may be the in vivo counterpart of stromal cells with the above-described vascular smooth muscle phenotype.     

New developments in the regulation of intestinal copper absorption

The transition metal copper is an essential trace element involved in many enzymatic processes that require redox-chemistry. The redox-activity of copper is potentially harmful. Severe imbalance of copper homeostasis can occur with some hereditary disorders of copper metabolism. Copper is acquired from the diet by intestinal absorption and is subsequently distributed throughout the body. The regulation of intestinal copper absorption to maintain whole-body copper homeostasis is currently poorly understood. This review evaluates novel findings regarding the molecular mechanism of intestinal copper uptake. The role of recently identified transporters in enterocyte copper uptake and excretion into the portal circulation is described, and the regulation of dietary copper uptake during physiological and pathophysiological conditions is discussed.     

Comparison of daclizumab,an interleukin 2 receptor antibody,to anti-thymocyte globulin-Fresenius induction therapy in kidney transplantation

The efficacy and safety of daclizumab and anti-thymocyte globulin-Fresenius (ATG-F) as induction therapy in kidney transplantation (KT) were investigated in 45 KT performed in our center between March and May 2002. Group II (n=10) received daclizumab as induction therapy, and Group I (n=35) were induced with a single intraoperative bolus therapy of ATG-F. All patients were at low-risk, and the recipient and donor demographics, as well the immunosuppression regimen employed were comparable in both groups. Drug safety, assessed by the occurrence of side effects, was almost comparable in the two groups, except for more thrombocytopenia in Group II (P<0.0004). Acute rejection (AR) occurred in 10% in Group I and 11.4% in Group II (P=NS). There were more infections in Group II (42.8%) than in Group I (10%) (P<0.009). Bacterial and viral infections were more common in Group II (69 and 23%) than in Group I (10 and 0%) (P<0.05). The hospital stay was similar in both groups. Mean serum creatinine levels upon discharge, at 1, 3 and 6 months were: 1.23+/-0.11, 1.21+/-0.06, 1.25+/-0.11 and 1.35+/-0.08 in Group I and 2.18+/-0.43, 1.49+/-0.16, 1.49+/-0.16 and 1.35+/-0.08 in Group II, respectively. While better serum creatinine levels were observed in Group I upon discharge (P<0.048), this was due to the presence of more sensitized patients in Group II. The 6 months actuarial patient and graft survival were identical in both groups (100 and 100%, respectively). Although both daclizumab and ATG-F were effective and safe as induction therapy in KT, less bacterial and viral infections and lower early serum creatinine levels were noted in daclizumab-treated patients.     

Prevention by retinoids of azoxymethane-induced tumors and aberrant crypt foci and their modulation of cell proliferation in the colon of rats

Retinoids are proposed chemopreventive agents that inhibit cell proliferation and induce differentiation. Their ability to prevent azoxymethane (AOM)-induced aberrant crypt foci (ACF) and tumors and to modulate cell proliferation was investigated in the colon of male F344 rats. Thirteen retinoids were evaluated for prevention of ACF and two of them, 9-cis-retinoic acid (RA) and 4-(hydroxyphenyl)retinamide (4- HPR), were also evaluated for prevention of colon cancer. The retinoids were administered continuously in the diet starting 1 week prior to the first of two weekly 15 mg/kg i.p. injections of AOM and for a total of either 5 or 36 weeks in order to evaluate their effect on colonic ACF and tumors. At a concentration of 1 mmol/kg diet, 2- (carboxyphenyl)retinamide caused the greatest reduction (57.7%) in the yield of ACF. 9-cis-RA was toxic at 1 mmol/kg so that it was evaluated at 0.1 mmol/kg, resulting in a 41.6% reduction in ACF. The ability of the retinoids to reduce the proliferating cell nuclear antigen (PCNA) labeling index in ACF and in non-involved crypts correlated with their ability to prevent ACF. Both 9-cis-RA (0.1 and 0.2 mmol/kg diet) and 4- HPR (1 and 2 mmol/kg diet) were highly effective in decreasing the yield of AOM-induced colon tumors. In summary, retinoids were demonstrated to reduce cell proliferation and to prevent ACF and tumors in the colon, suggesting promise as preventive agents for colon cancer.      

Adhesive capsulitis of the wrist: arthrographic diagnosis

Persistent pain and decreased range of motion are disabling complications of wrist trauma. Between 1978 and 1986, in ten patients with persistent pain following trauma, arthrography depicted changes characteristic of adhesive capsulitis. Adhesive capsulitis has been described in the shoulder, hip, and ankle, but little mention has been made of this entity in other joints. Confirmation of this diagnosis requires arthrography, since there are no characteristic findings on plain radiographs. Typical arthrographic findings include decreased capacity, small volar and styloid recesses, and adhesions preventing complete opacification of the joint. The arthrographic diagnosis allows proper institution of appropriate therapy.     

EFFECTS ON GROWTH HORMONE SECRETION FOLLOWING INTRAVENOUS AND SUBCUTANEOUS INJECTIONS OF GROWTH HORMONE-RELEASING FACTOR (hGRF-44 NH2): COMPARISON OF IMMUNOREACTIVE PLASMA GRF LEVELS

The effects of subcutaneous administration of three doses of human growth hormone-releasing factor (hGRF-44 NH2 or hGRF) at doses of 100, 300 and 600 micrograms were studied in six normal young men. GH responses obtained with 100 and 300 micrograms were negligible. In contrast, the 600 micrograms dose gave a profile of response comparable in timing and magnitude to that obtained with i.v. hGRF at maximal effect doses (20, 80, 100 micrograms). Plasma immunoreactive hGRF levels (IR-hGRF) were compared after s.c. and i.v. hGRF. Mean maximal plasma concentrations were comparable with s.c. 600 micrograms and i.v. 20 micrograms. Peaks occurred earlier with i.v. hGRF (5 min as opposed to 15 min): however, return to undetectable values was obtained between 90 and 120 min after s.c. or i.v. injections. These data suggest a great loss of the peptide between the subcutaneous space and blood, without delayed absorption. High variability in plasma IR-hGRF concentrations between the subjects after the same s.c. doses was observed.     

Thiol groups and reduced acidogenicity of dental plaque in the presence of metal ions in vivo

Metal ions are known to influence the cariogenicity of dental plaque. Inhibition of acid metabolism in plaque may be of importance in this respect. Metal ions inhibit the acidogenicity of dental plaque to a different extent and it has been suggested that an enzyme inhibition based on oxidation of thiol groups may explain this observation. The aim of the present study was to evaluate the significance of oxidation of thiol groups in the inhibition of acid production in plaque by silver, tin and zinc salts. Nine subjects with 3-d sucrose induced plaque received topical applications of the metal ions. Cysteine or gilutathione, which are known to reverse thiol oxidations, were then applied in one side of the mouth. Plaque pH measurements, in the presence of sucrose, were performed prior to and up to 2 h after treatment. The results showed that the acid production inhibited by the metal ions was reactivated by cysteine or glutathione. Iodoacetamide and ρ-chloromercuribenzoate were also shown to inhibit acid formation in dental plaque. The high affinity silver, tin and zinc have for SH groups, the observed inhibitory effect of these metals, the reactivation of the metabolism by monothiols and the fact that organic sulfhydryl reagents inhibit acid formation in plaque indicate that oxidation of thiol groups may be the mechanism by which these metals exert their effect.     

Activation of PAR2 receptors sensitizes primary afferents and causes leukocyte rolling and adherence in the rat knee joint

Background and Purpose

The PAR₂ receptors are involved in chronic arthritis by mechanisms that are as yet unclear. Here, we examined PAR₂ activation in the rat knee joint.

Experimental Approach

PAR₂ in rat knee joint dorsal root ganglia (DRG) cells at L3-L5, retrogradely labelled with Fluoro-gold (FG) were demonstrated immunohistochemically. Electrophysiological recordings from knee joint nerve fibres in urethane anaesthetized Wistar rats assessed the effects of stimulating joint PAR₂ with its activating peptide, 2-furoyl-LIGRLO-NH₂ (1–100 nmol·100 μL⁻¹, via close intra-arterial injection). Fibre firing rate was recorded during joint rotations before and 15 min after administration of PAR₂ activating peptide or control peptide. Leukocyte kinetics in the synovial vasculature upon PAR₂ activation were followed by intravital microscopy for 60 min after perfusion of 2-furoyl-LIGRLO-NH₂ or control peptide. Roles for transient receptor potential vanilloid-1 (TRPV1) or neurokinin-1 (NK₁) receptors in the PAR₂ responses were assessed using the selective antagonists, SB366791 and RP67580 respectively.

Key Results

PAR₂ were expressed in 59 ± 5% of FG-positive DRG cells; 100 nmol 2-furoyl-LIGRLO-NH₂ increased joint fibre firing rate during normal and noxious rotation, maximal at 3 min (normal; 110 ± 43%, noxious; 90 ± 31%). 2-Furoyl-LIGRLO-NH₂ also significantly increased leukocyte rolling and adhesion over 60 min. All these effects were blocked by pre-treatment with SB366791 and RP67580 (P < 0.05 compared with 2-furoyl-LIGRLO-NH₂ alone).

Conclusions and Implications

PAR₂ receptors play an acute inflammatory role in the knee joint via TRPV1- and NK₁-dependent mechanisms involving both PAR₂-mediated neuronal sensitization and leukocyte trafficking.