The gp130 cytokines interleukin-11 and ciliary neurotropic factor regulate through specific receptors the function and growth of lactosomatotropic and folliculostellate pituitary cell lines.

Two of the most potent cytokines regulating anterior pituitary cell function are leukemia inhibitory factor and interleukin-6 (IL-6), which belong to the cytokine receptor family using the common gp130 signal transducer. We studied the actions of two other members of this family, IL-11 and ciliary neurotropic factor (CNTF), on folliculostellate (FS) cells (TtT/GF cell line) and lactosomatotropic cells (GH3 cell line). The messenger RNA (mRNA) for the alpha-chain specific for the IL-11 receptor (1.7 kb) and CNTF receptor (2 kb) are expressed on both cell types. In addition, we detected CNTF receptor mRNA in normal rat anterior pituitary cells. IL-11 (1.25-5 nM) dose dependently stimulated the proliferation of FS cells. CNTF, at doses from 0.4-2 nM, also significantly stimulated the growth of these cells. In addition, both cytokines significantly stimulated proliferation of lactosomatotropic GH3 cells, and CNTF stimulated hormone production (GH and PRL) at 24 h by these cells. At 16-72 h, IL-11 stimulates the secretion of the angiogenic factor vascular endothelial growth factor by FS cells. In addition, both GH3 and FS cells express CNTF mRNA. These data suggest that IL-11 and CNTF may act as growth and regulatory factors in anterior pituitary cells.

Results of preprocedure and postprocedure toe cultures in orthopaedic surgery.

This study was to determine whether there is any benefit to wrapping the toes sterilely during orthopaedic procedures not involving the foot but performed on the lower extremity. The group studied consisted of 12 patients who had an orthopaedic procedure performed in which the foot and toes were included in the surgical prep, but not involved in the surgical procedure. Nine of the 12 patients (75%) had positive results from preprocedural aerobic cultures and two of the 12 (16.6%) had positive results from preprocedural fungal cultures. Recolonization of the bacteria between the toes was also demonstrated. Sterile draping of the toes would minimize the risk of infection and also protect against bacteria that recolonize during the procedure.

Pancreas allograft rejection: correlation of transduodenal core biopsy with Doppler resistive index.

PURPOSE: To determine the usefulness of sonographically obtained resistive indexes (RIs) in the diagnosis of pancreas allograft rejection. MATERIALS AND METHODS: Findings were studied from 78 transduodenal pancreas allograft biopsies that were ultrasound-guided and cystoscopically directed. The 78 biopsies included 40 that were compared directly with baseline RI data. Biopsies were categorized by result and correlated with concurrent RIs (including 26 RIs obtained within 24 hours of biopsy) with the chi2 test for categoric variables and the Student t test for continuous variables. Sensitivity, specificity, and positive and negative predictive values were calculated with standardized formulas. RESULTS: The mean RIs between the no rejection, mild acute rejection, and moderate acute rejection groups were not statistically significantly different; however, the mean RI associated with chronic rejection was statistically significantly higher (P < .05) than that in the other groups. The sensitivity, specificity, and positive and negative predictive values of either an elevated RI (> 0.70) or greater than 10% increase in the RI above the baseline value in the diagnosis of acute rejection were approximately 50%. CONCLUSION: Neither the absolute level of the RI nor the relative increase was correlated with acute rejection proved at biopsy. Changes in RIs after pancreas transplantation were a poor indicator of acute rejection, but the absolute value of the RI was elevated in cases of chronic rejection.

Rat mesangial cells have a selective role in macrophage recruitment and activation.

In proliferative glomerulonephritis glomeruli are the target of an inflammatory reaction involving macrophage recruitment and activation. We examined the role of mesangial cells in this process. Supernatants from basal, IL-1, IFN-tau or LPS-stimulated rat mesangial cells (MCS) were tested for chemotactic, colony-stimulating and activation effects on macrophages in vitro. IL-1-stimulated MCS produced a macrophage chemoattractant (p = 0.007 compared with basal MCS) and MCP-1 mRNA was detected in IL-1-stimulated mesangial cells. LPS or IL-1-stimulated MCS produced colony-stimulating activity (LPS p < 0.05, IL-1 p < 0.01, compared with basal MCS or control supernatant, CS). Macrophage activation, assessed by nitric oxide generation, was suppressed. This evidence from functional bioassays supports a selective role for mesangial cells in the control of macrophage-induced glomerular injury, whereby activated mesangial cells participate in the recruitment and proliferation of infiltrating macrophages, and suppresses at least one field of macrophage activation, namely nitric oxide generation.

Arginine metabolism in experimental glomerulonephritis: interaction between nitric oxide synthase and arginase.

L-Arginine is metabolized by two pathways: 1) by nitric oxide synthase (NOS) to nitric oxide (NO) and 2) by arginase forming urea and L-ornithine. Inflammatory responses may involve a balance between the pathways, as NO is cytotoxic and vasodilatory and L-ornithine is a promoter of cell proliferation and matrix synthesis. In experimental glomerulonephritis we have previously shown that NOS is activated in nephritic glomeruli. We have now examined both pathways of L-arginine metabolism to study competition for L-arginine, temporal variation, and the sources of NOS and arginase. Acute in situ glomerulonephritis was induced in rats, and glomeruli were studied at 1, 4, and 7 days. Both NOS and arginase activities were present. There was temporal variation: NOS activity was highest on day 1 and arginase activity on day 4; both declined by day 7. Competition between the pathways was demonstrated by increased urea synthesis in the presence of NG-monomethyl-L-arginine, an inhibitor of NOS. Measurement of NOS and arginase activities in macrophages isolated from nephritic glomeruli showed that these cells were a major source of glomerular NOS but not arginase activity. In contrast, high arginase activity but low NO production was identified in cultured rat glomerular mesangial cells. These studies show differential temporal variation in expression of NOS and arginase pathways of arginine metabolism in experimental glomerulonephritis. We have found two factors that may contribute to this: 1) competition for substrate L-arginine between the two pathways and 2) different cellular sources. We hypothesize that the balance between these pathways is a mechanism regulating injury, hemodynamics, and mesangial cell proliferation.

Expression of the gene for inducible nitric oxide synthase in experimental glomerulonephritis in the rat.

Nitrite, a stable product of nitric oxide (NO), is synthesized in vitro by glomeruli in experimental glomerulonephritis. We have now studied the expression of the gene for inducible NO synthase (iNOS) in accelerated nephrotoxic nephritis (NTN). The purpose of the study was to confirm in vivo induction of iNOS in this model of immune complex disease, and to relate the onset of induction and the level of expression to pathogenic events in the model. Glomeruli from rats with NTN were isolated at 6 h, 24 h and 2, 4 and 7 days and total RNA extracted. RNA (10 micrograms) was reverse transcribed and polymerase chain reaction (PCR) was performed with primers homologous to rat vascular smooth muscle iNOS and rat beta actin. A 222-base PCR product corresponding to iNOS mRNA was present in all experimental animals. iNOS expression was also found in activated macrophages, neutrophils and IL-1-stimulated but not unstimulated mesangial cells. Quantitative competitive PCR was carried out on glomerular samples using a 514-bp mutant of a 735-bp PCR product. iNOS expression was present at low levels in normal glomeruli and was markedly enhanced at 6 h after the induction of glomerulonephritis and peaked at 24 h. Increased iNOS expression persisted to day 7. beta actin mRNA levels were similar in all glomerular specimens. This study demonstrates that there is in vivo induction of iNOS in immune complex glomerulonephritis, corresponding to the generation of nitrite we have previously reported. iNOS gene expression is detectable within 6 h of induction of NTN, indicating the onset of gene transcription is closely related to the initial formation of immune complexes.

Induction of nitric oxide synthase in rat immune complex glomerulonephritis.

Nitric oxide (NO) is a biological mediator which is synthesized from L-arginine by a family of nitric oxide synthases (NOS). Previously we have shown that NO is synthesized ex vivo by glomeruli obtained from animals with acute immune complex glomerulonephritis. We have now sought evidence for the in vivo induction of NOS in glomeruli by immunohistochemistry using specific antisera raised against a peptide sequence of inducible mouse macrophage NOS and by in situ hybridization. The expression of the enzyme was studied in kidneys of rats with acute unilateral immune complex glomerulonephritis, induced by cationized IgG, by immunohistochemistry. Inducible NOS (iNOS) was present in glomeruli in nephritic (left) kidneys at the time of maximum macrophage infiltration, both within intraglomerular mononuclear cells and cells emigrating into Bowman's space. iNOS expressing cells were also present in interstitial infiltrates. There was no expression in normal rat kidneys or in glomeruli in the non-nephritic (right) kidneys of experimental rats. In situ hybridization confirmed the immunohistochemical localization. These results provide the first direct evidence for the presence and localization of inducible NOS in glomeruli and support a significant role for NO in the pathogenesis of immune complex glomerulonephritis.

Glomerular NO synthase activity in mesangial cell immune injury.

Ex vivo synthesis of nitrite (NO2-) by nephritic glomeruli provides evidence of induction of nitric oxide (NO) in glomerulonephritis (GN). In macrophage-associated GN, the major source is infiltrating macrophages. As induction of NO synthesis has now been shown in cultured mesangial cells, we have examined whether in vivo mesangial proliferation is a source of NO2-. Mesangial proliferative GN was induced by intravenous anti-Thy1.1 (monoclonal antibody ER4). Isolated glomeruli were assayed for NO2- synthesis and macrophage infiltration on day 4 (mesangiolytic phase) and on day 7 (mesangial proliferation). On day 4, but not on day 7, basal NO2- was increased (8.3 +/- 1.8, controls 0.7 +/- 0.1 nmol/2,000 glomeruli/48 h; p = 0.05) and there was macrophage infiltration (60 +/- 15; controls 14 macrophages/glomerulus). At both times NO2- was elevated by exogenous IL1 or LPS, more significantly on day 4 than on day 7. Thus, mesangial proliferative lesions are not a source of basal NO2-, and macrophages are the most likely source. However, NO2- can be induced in mesangial proliferative glomeruli by exogenous stimuli, findings similar to those reported in cultured mesangial cells. Irradiation experiments in normal rats show that stimulated NO2- synthesis is inhibited by macrophage depletion. Therefore in neither normal nor proliferative glomeruli is there evidence for mesangial cell production of NO2-.

Isoprenaline reverses the slow force responses to a length change in isolated rabbit papillary muscle.

An alteration in the length of isolated cardiac muscle produces an immediate change in twitch force, then a slow further change in the same direction. We have found that the slow changes in force in rabbit papillary muscles are blocked or reversed by the beta-agonist, isoprenaline (1 microM). The abolition of the slow responses by isoprenaline was not due to saturation of the myofibrils with Ca2+, as the blockade continued if the extracellular [Ca2+] was reduced in the presence of isoprenaline so that twitch force was < 50% maximal. Ryanodine (1 microM) did not block the slow responses, suggesting that the sarcoplasmic reticulum does not mediate the responses. These results suggest that changes of intracellular [cAMP] may mediate, or at least modulate, the slow force responses to a length change in cardiac muscle.

Glomeruli synthesize nitrite in active Heymann nephritis; the source is infiltrating macrophages.

Glomeruli synthesize nitrite (NO2-) in experimental nephrotoxic nephritis, a model of glomerulonephritis where infiltrating macrophages are pathogenic. NO2- synthesis was studied in active Heymann nephritis (AHN), a model of membranous glomerulonephritis in which macrophages have not been implicated. Active Heymann nephritis (AHN) was induced with purified renal tubular epithelial antigen and adjuvants. Glomeruli isolated at seven to eight weeks after induction (proteinuria 183 +/- 28 mg/24 hr, N = 6; adjuvant controls, 1.2 +/- 0.8 mg/24 hr, N = 6) produced NO2- in culture spontaneously (7.1 +/- 1.4, adjuvant controls 2.1 +/- 0.9 nmol/2000 g/48 hours; P = 0.021) and in increased amount following LPS stimulation (12.1 +/- 2.8, controls 4.2 +/- 1.6 nmol/2000 g/48 hours; P = 0.047). Synthesis was inhibited by L-NMMA, a competitive inhibitor of NO synthase. Enzymic digestion of glomeruli plus staining with mouse anti-rat macrophage monoclonal antibody ED1 showed macrophage infiltration (32 +/- 6, adjuvant controls 14 +/- 2 macrophages/glomerulus; P = 0.002). Whole body irradiation (XR) suppressed NO2- production (LPS stimulated: 1.0 +/- 0.4, N = 5; non-XR controls 7.2 +/- 4.6 nmol/2000 g/48 hours; N = 5, P = 0.016) and macrophage infiltration (1.1 +/- 0.5; non-XR controls 30 +/- 12 macrophages/glomerulus; P = 0.008) but had no effect on proteinuria. Irradiation with renal shielding confirmed the close correlation between glomerular NO2- synthesis and glomerular macrophage numbers (rs = 0.837, P less than 0.001). These results show that macrophages infiltrate glomeruli in AHN; they are the source of NO2- in this model. Neither macrophages nor NO2- are the cause of proteinuria.