Atrial natriuretic peptide and renal adaptation to contralateral nephrectomy in healthy man.

Atrial natriuretic peptide (ANP), angiotensin II (AII), aldosterone (Aldo) and arginine vasopressin (AVP) in plasma were determined in 12 healthy renal transplant donors before and 5, 12, 26, 54 days after uninephrectomy (Nx) in order to study the possible role of these hormones in functional adaptation to acute reduction in renal mass. Glomerular and tubular function was studied by measurements of the clearances of 51Cr-EDTA, lithium, sodium, potassium, and albumin. ANP was 7.4 +/- 3.1 pmol l-1 (mean +/- SD) before Nx and 8.7 +/- 6.1 pmol l-1 at 5 days after Nx and remained at this level through the observation period. Aldo showed a non-significant transient fall at 5 days after Nx. AII and AVP remained normal after Nx. At 5 days after Nx glomerular filtration rate (GFR) of the remaining kidney had risen from 45 +/- 7 ml min-1 before Nx to 57 +/- 8 ml min-1 (p less than 0.01), lithium clearance had risen from 13 +/- 2 ml min-1 before Nx to 20 +/- 7 ml min-1 (p less than 0.01), and sodium and water balance was normal. To conclude, plasma ANP, AII, Aldo and AVP do not appear to be responsible for the hyperfiltration and depression of fractional proximal sodium and water reabsorption observed in recently uninephrectomized man with normal sodium and water balance.     

The renal handling of sodium and water is not affected by the standard-dose cisplatin treatment for testicular cancer

Renal clearances of 51Cr-EDTA, lithium, sodium and potassium were measured before and after each of four consecutive treatment series with cisplatin in 15 men with testicular cancer. Since lithium is reabsorbed like sodium and water in the proximal tubules, but not reabsorbed to any measurable degree in the remainder of the nephron, lithium clearance equals the amount of fluid delivered from the end of the proximal straight segment to the thin descending limb of the loop of Henle. From the clearances of lithium and sodium, distal tubular reabsorption can be calculated. Lithium clearance and all other parameters of glomerular filtration and renal sodium handling remained normal throughout the study (with the exception of a fall in fractional sodium excretion after the first treatment series). Plasma magnesium declined during all four treatment periods, signifying renal magnesium wasting.     

The role of SAP in murine CD150 (SLAM)-mediated T-cell proliferation and interferon gamma production

CD150 (signaling lymphocyte activation molecule [SLAM]) is a self-ligand cell surface glycoprotein expressed on T cells, B cells, macrophages, and dendritic cells. To further explore the role of CD150 signaling in costimulation and T(H)1 priming we have generated a panel of rat antimouse CD150 monoclonal antibodies. CD150 cell surface expression is up-regulated with rapid kinetics in activated T cells and lipopolysaccharide/interferon gamma (IFN-gamma)-activated macrophages. Anti-CD150 triggering induces strong costimulation of T cells triggered through CD3. DNA synthesis of murine T cells induced by anti-CD150 is not dependent on SLAM-associated protein (SAP, SH2D1A), because anti-CD150 induces similar levels of DNA synthesis in SAP(-/-) T cells. Antibodies to CD150 also enhance IFN-gamma production both in wild-type and SAP(-/-) T cells during primary stimulation. The level of IFN-gamma production is higher in SAP(-/-) T cells than in wild-type T cells. Anti-CD150 antibodies also synergize with interleukin 12 (IL-12) treatment in up-regulation of IL-12 receptor beta(2) mRNA during T(H)1 priming, and inhibit primary T(H)2 polarization in an IFN-gamma-dependent fashion. Cross-linking CD150 on CD4 T cells induces rapid serine phosphorylation of Akt/PKB. We speculate that this is an important pathway contributing to CD150-mediated T-cell proliferation.     

Induction of pyruvate carboxylase apoenzyme and holoenzyme in 3T3-L1 cells during differentiation

The specific activity of pyruvate carboxylase [pyruvate:carbon-dioxide ligase (ADP-forming); EC 6.4.1.1] in 3T3-L1 cells increases approximately 20-fold when these cells differentiate to an adipocyte-like form [Mackall, J. C. & Lane, M. D. (1977) Biochem. Biophys. Res. Commun. 79, 720-725]. A specific antibody to the purified rat liver enzyme quantitatively precipitated pyruvate carboxylase from 3T3-L1 crude homogenates. Use of this immunological technique permitted us to demonstrate that the increase in pyruvate carboxylase activity is due to an increase in the intracellular concentration of the enzyme. The content of pyruvate carboxylase in differentiated 3T3-L1 cells is sufficiently high (1-2% of total protein) that the increase in this large protein (subunit M_r = 130,000) can be visualized when 3T3-L1 crude extracts are subjected to electrophoresis on sodium dodecyl sulfate/polyacrylamide gels. When 3T3-L1 cells differentiated in the presence of avidin, they contained less than 5% of the pyruvate carboxylase activity of cells that differentiated in the absence of avidin. However, the immunoprecipitable pyruvate carboxylase content of the avidin-treated cells was essentially the same as that of cells that differentiated without avidin. Full activity of the enzyme was rapidly restored in the avidin-treated cells upon the addition of excess biotin. The recovery of activity was closely correlated with the incorporation of [¹⁴C]biotin into immunoprecipitable pyruvate carboxylase. The rapidity with which the activity was restored and the insensitivity of the process to inhibitors of protein synthesis strongly suggest that the apoenzyme of pyruvate carboxylase accumulates during differentiation in the presence of avidin.     

Chlamydia pneumoniae infection and its role in asthma and chronic obstructive pulmonary disease.

Chlamydia pneumoniae (CP) is a common cause of respiratory tract infections, and several studies have asked whether it may play a pathogenic role in connection with bronchial asthma and chronic obstructive pulmonary disease (COPD). Evidence that CP infection is associated with these diseases is a cardinal item. However, evaluation of CP infection is hampered by difficulties in obtaining agreement on the definition of a gold standard. In the literature, serology is based on different cutoff points of antibody titres, which complicates the definition of CP seropositive findings and the classification of acute infection, chronic and past infection. In connection with acute and chronic infection, it is important to demonstrate the presence of CP by culture or polymerase chain reaction (PCR) in the respiratory tract, especially in the lower airways. Often, the results of serology is not associated with the findings by culture or PCR testing, which may involve the risk of inconclusive evidence. Evaluation of a possible presence of CP by clinical improvement after treatment with antibiotics is difficult since uncontrolled studies have been used and other microorganisms are also affected by antibiotics. Furthermore, many patients improve without antibiotics, and improvement has also been observed in patients remaining culture positive after treatment with antibiotics. It should also be noted that the antiinflammatory effects of antibiotics may improve the clinical status of patients. Despite these obstacles, studies point to the possibility that in some patients acute CP infections may lead to acute exacerbations of bronchial asthma. Whether a persistent CP infection contributes to chronic asthma or severe COPD, or whether it incites the diseases in previously healthy individuals is a question for further studies. Whether a causal relationship exists between CP infection and obstructive pulmonary disease or whether these patients are more susceptible to CP infection is unknown. Nevertheless, a cooperative role of CP in the proinflammatory mechanisms involved in these diseases remains to be examined since cellular studies show that CP stimulates the production and expression of cytokines, chemokines and adhesion molecules, actions that may amplify and prolong the inflammation.     

Palliation of rectosigmoid neoplasms with Nd:YAG laser treatment

PURPOSE: The aim of this study was to evaluate the effect of Nd:YAG laser treatment as palliation for rectosigmoid neoplasms. METHODS: Indications for laser therapy, the degree and duration of symptom relief, complication rate, and survival time were recorded in consecutive patients. RESULTS: Seventy-four patients entered the study. Poor general health in older patients, and disseminated or complicating disease were the most frequent indications for therapy. Fifty-five (74 percent) patients experienced good symptomatic effect from the treatment. Six complications occurred: five cases of perforation and one case of moderate bleeding. There was no mortality. The median survival was seven months (range, 14 days–39 months). CONCLUSION: Laser treatment is a good palliative method in patients with colorectal cancer, especially in patients with local recurrence or symptoms from nonresected tumors.     

Effects of intracoronary melatonin on ischemia–reperfusion injury in ST-elevation myocardial infarction

Acute coronary occlusion is effectively treated by primary percutaneous coronary intervention. However, myocardial ischemia–reperfusion injury is at the moment an unavoidable consequence of the procedure. Oxidative stress is central in the development of ischemia–reperfusion injury. Melatonin, an endogenous hormone, acts through antioxidant mechanisms and could potentially minimize the myocardial injury. The aim of the experimental study was to examine the cardioprotective effects of melatonin in a porcine closed-chest reperfused infarction model. A total of 20 landrace pigs were randomized to a dosage of 200 mg (0.4 mg/mL) melatonin or placebo (saline). The intervention was administered intracoronary and intravenous. Infarct size, area at risk and microvascular obstruction were determined ex vivo by cardiovascular magnetic resonance imaging. Myocardial salvage index was calculated. The plasma levels of high-sensitive troponin T were assessed repeatedly. The experimenters were blinded with regard to treatment regimen. Melatonin did not significantly increase myocardial salvage index compared with placebo [melatonin 21.8 % (16.1; 24.8) vs. placebo 20.2 % (16.9; 27.0), p = 1.00]. The extent of microvascular obstruction was similar between the groups [melatonin 3.8 % (2.7; 7.1) vs. placebo 3.7 % (1.3; 7.7), p = 0.96]. The area under the curve for high-sensitive troponin T release was insignificantly reduced by 32 % in the melatonin group [AUC melatonin 12,343.9 (6,889.2; 20,147.4) ng h/L vs. AUC placebo 18,285.3 (5,180.4; 23,716.8) ng h/L, p = 0.82]. Combined intracoronary and intravenous treatment with melatonin did not reduce myocardial reperfusion injury. The lack of a positive effect could be due to an ineffective dose of melatonin, a type II error or the timing of administration.     

Arthroscopy of the elbow: Diagnosis and extraction of loose bodies

Arthroscopy of the elbow was performed in 35 cases of suspected loose bodies. Loose bodies were found in 13 cases. Preoperative radiographs were falsely negative in two cases and falsely positive in 12. In ten cases arthroscopic removal was attempted; it succeeded in six cases. When no loose bodies were found, the most common diagnosis was degenerative joint disease.

Arthroscopy is recommended for diagnosis and treatment of loose bodies in the elbow joint.