Enhancing of anti-viral activity against HIV-1 by stimulation of CD8+ T cells with thymic peptides

HIV-1 can be neutralized by soluble factors produced and secreted by activated CD8+ T cells. Production of such anti-viral CD8 factors (including chemokines) can be induced with IL-2 or phytohaemagglutinin (PHA). In addition to PHA or IL-2, we have co-stimulated CD8+ T cells with PHA/IL-2 and a mixture of thymic peptides (TP) of molecular weights below 10 kD. For the activation, CD8+ T cells were purified from peripheral blood mononuclear cells of HIV-1- individuals and any resultant anti-viral activity was monitored using an HIV-1 neutralization assay. Using HIV-1 isolates highly resistant to chemokine inhibition we detected significantly higher levels of HIV-1 neutralizing activity in CD8+ T cell culture supernatants which had been co-activated with TP. When the TP-induced anti-viral activity was monitored, neutralization of both non-syncytia-inducing (NSI) and syncytia-inducing (SI) patient isolates was enhanced by 38% (NSI, PHA +/- TP), 66% (SI, PHA +/- TP), 28% (NSI, IL-2 +/- TP), and 57% (SI, IL-2 +/- TP) compared with the anti-viral activity present in supernatants from CD8+ T cell cultures stimulated only with PHA or IL-2. Peptide sequence analysis of purified TP showed that the TP mixture predominantly contains peptides with homology to human histone and collagen sequences. Our data demonstrate that CD8+ T cells are additionally activated by a mixture of TP. In this way, the production of HIV-1 neutralizing CD8 factors can be enhanced.

Transplantable sites confer calcium sensitivity to BK channels

Both intracellular calcium and voltage activate Slo1, a high-conductance potassium channel, linking calcium with electrical excitability. Using molecular techniques, we created a calcium-insensitive variant of this channel gated by voltage alone. Calcium sensitivity was restored by adding back small portions of the carboxyl (C)-terminal 'tail' domain. Two separate regions of the tail independently conferred different degrees of calcium sensitivity; together, they restored essentially wild-type calcium dependence. These results suggest that, in the absence of calcium, the Slo1 tail inhibits voltage-dependent gating, and that calcium removes this inhibition. Slo1 may have evolved from an ancestral voltage-sensitive potassium channel represented by the core; the tail may represent the more recent addition of a calcium-dependent modulatory domain.

Compliance curves during peritoneal dialysate infusion are like a distensible tube and are similar at multiple UGI sites

OBJECTIVE

Disorders from increased intraabdominal pressure (IAP) result from filling the abdominal cavity beyond its capacity. The aims of this study were 1) to examine pressure:volume curves as fluid is infused into the intraabdominal cavity, and 2) to ascertain the best UGI site for indirect IAP measurements.

METHODS

Chronic ambulatory peritoneal dialysis patients were studied (n = 4) supine. On day 1, manometry catheters measured IAP indirectly (intragastric and intrarectal) and intraesophageal (three sites) pressure. On day 2, antral-duodenal-jejunal manometry was performed to compare indirectly measured IAP at multiple sites. On both days, dialysate was infused at 200 ml/min until IAP was > or = 15 mm Hg or patient experienced severe discomfort.

RESULTS

Filling had three phases: 1) an initial small increase in IAP as infusion began; 2) minimal further increase in IAP during infusion to about 3 L concurrent with a progressive increase in abdominal girth and mild abdominal discomfort; and 3) a linear increase in IAP with infusion > 3 L concurrent with intense abdominal discomfort and little increase in abdominal girth. During study day 2, intragastric, intraduodenal, and intrajejunal pressures were usually similar.

CONCLUSIONS

The compliance curve of the abdomen with filling is similar to that of the bladder and large veins. Compliance curves with provocative meals may be useful in evaluating postprandial abdominal pain, dyspepsia, and bloating.

Time of peritoneal cavity exposure influences postoperative glucose production

PURPOSE

To examine the effect of the duration of peritoneal cavity exposure on glucose metabolism after abdominal surgery.

METHODS

In eight otherwise healthy patients (ASA 1) with uterine myoma, endogenous glucose production (Ra glucose) was measured immediately before and two hours after abdominal hysterectomy by a stable isotope dilution technique using primed continuous infusions of [6,6-2H2]-glucose. Plasma concentrations of glucose, lactate, insulin, glucagon, cortisol, epinephrine and norepinephrine were determined before, during (5 and 60 min after peritoneal incision, skin closure) and two hours after surgery. Pre- and postoperative glucose clearance was calculated as Ra glucose divided by plasma glucose concentration.

RESULTS

Ra glucose increased from 11.8 +/- 1.2 to 16.8 +/- 3.2 micromol x kg(-1) x min(-1) two hours after hysterectomy (P < 0.05) with a correlation between the degree of increase and the time of peritoneal cavity exposure (r = 0.859, P = 0.006). Plasma glucose concentration increased after surgery from 4.7 +/- 0.8 to 8.3 +/- 1.9 mmol x l(-1) (P < 0.05), while glucose clearance decreased from 2.6 +/- 0.4 to 2.1 +/- 0.4 ml x kg(-1) x min(-1) (P < 0.05). Plasma concentrations of cortisol and catecholamines increased after hysterectomy (cortisol from 6 +/- 2 to 31 +/- 7 microg x dl(-1), epinephrine from 25 +/- 14 to 205 +/- 132 pg x ml(-1), norepinephrine from 182 +/- 82 to 377 +/- 132 pg x ml(-1), P < 0.05), whereas plasma lactate, insulin and glucagon concentrations remained unchanged.

CONCLUSION

The magnitude of increase of glucose production after abdominal hysterectomy is associated with the duration of peritoneal cavity exposure.

Comparison of the effectiveness of adenovirus vectors expressing cyclin kinase inhibitors p16INK4A, p18INK4C, p19INK4D, p21(WAF1/CIP1) and p27KIP1 in inducing cell cycle arrest, apoptosis and inhibition of tumorigenicity

Cell cycle regulatory proteins are important candidates for therapeutic tumour suppressors. Adenovirus vectors were constructed to overexpress cyclin kinase inhibitors p16INK4A, p18INK4C, p19INK4D, p21(WAF1/CIP1) and p27KIP1 under the control of the murine cytomegalovirus immediate early gene promoter. These vectors directed the efficient expression of each of the cyclin kinase inhibitors and induced growth arrest, inhibited DNA synthesis, and prevented phosphorylation of the retinoblastoma protein (pRb) in cell lines expressing functional pRb. In pRb-deficient cells, expression of the cyclin kinase inhibitors was not effective in inhibiting DNA replication or growth arrest. Interestingly, three of the cyclin kinase inhibitors, p16, p18 and p27 were found to induce apoptotic death in transduced HeLa and A549 cells. When the vectors were tested for their ability to inhibit tumorigenicity in a polyomavirus middle T antigen model of murine breast carcinoma, expression of the cyclin kinase inhibitors resulted in a delay in tumour formation that varied from several weeks for the p19 expressing vector to greater than 25 weeks for the p27 expressing vector. When tumours were injected directly with the adenovirus vectors expressing the cyclin kinase inhibitors, only treatment with the vector expressing p16 resulted in a delay in tumour growth.

Control of cell cycle progression by c-Jun is p53 dependent

The c-jun proto-oncogene encodes a component of the mitogen-inducible immediate-early transcription factor AP-1 and has been implicated as a positive regulator of cell proliferation and G1-to-S-phase progression. Here we report that fibroblasts derived from c-jun-/- mouse fetuses exhibit a severe proliferation defect and undergo a prolonged crisis before spontaneous immortalization. The cyclin D1- and cyclin E-dependent kinases (CDKs) and transcription factor E2F are poorly activated, resulting in inefficient G1-to-S-phase progression. Furthermore, the absence of c-Jun results in elevated expression of the tumor suppressor gene p53 and its target gene, the CDK inhibitor p21, whereas overexpression of c-Jun represses p53 and p21 expression and accelerates cell proliferation. Surprisingly, protein stabilization, the common mechanism of p53 regulation, is not involved in up-regulation of p53 in c-jun-/- fibroblasts. Rather, c-Jun regulates transcription of p53 negatively by direct binding to a variant AP-1 site in the p53 promoter. Importantly, deletion of p53 abrogates all defects of cells lacking c-Jun in cell cycle progression, proliferation, immortalization, and activation of G1 CDKs and E2F. These results demonstrate that an essential, rate-limiting function of c-Jun in fibroblast proliferation is negative regulation of p53 expression, and establish a mechanistic link between c-Jun-dependent mitogenic signaling and cell-cycle regulation.

JNK2 is required for efficient T-cell activation and apoptosis but not for normal lymphocyte development

BACKGROUND

The Jun N-terminal kinase (JNK) signaling pathway has been implicated in cell proliferation and apoptosis, but its function seems to depend on the cell type and inducing signal. In T cells, JNK has been implicated in both antigen-induced activation and apoptosis.

RESULTS

We generated mice lacking the JNK2 isozymes. The mutant mice were healthy and fertile but defective in peripheral T-cell activation induced by antibody to the CD3 component of the T-cell receptor (TCR) complex - proliferation and production of interleukin-2 (IL-2), IL-4 and interferon-gamma (IFN-gamma) were reduced. The proliferation defect was restored by exogenous IL-2. B-cell activation was normal in the absence of JNK2. Activation-induced peripheral T-cell apoptosis was comparable between mutant and wild-type mice, but immature (CD4(+) CD8(+)) thymocytes lacking JNK2 were resistant to apoptosis induced by administration of anti-CD3 antibody in vivo. The lack of JNK2 also resulted in partial resistance of thymocytes to anti-CD3 antibody in vitro, but had little or no effect on apoptosis induced by anti-Fas antibody, dexamethasone or ultraviolet-C (UVC) radiation.

CONCLUSIONS

JNK2 is essential for efficient activation of peripheral T cells but not B cells. Peripheral T-cell activation is probably required indirectly for induction of thymocyte apoptosis resulting from administration of anti-CD3 antibody in vivo. JNK2 functions in a cell-type-specific and stimulus-dependent manner, being required for apoptosis of immature thymocytes induced by anti-CD3 antibody but not for apoptosis induced by anti-Fas antibody, UVC or dexamethasone. JNK2 is not required for activation-induced cell death of mature T cells.

[New approaches to tissue management in minimal invasive pediatric surgery]

Tissue management in minimally invasive surgery plays an important role in the indication for and feasibility of surgical interventions. Hemostasis and sealing of larger areas are possible with minimally invasive tissue gluing in liquid and bandage-bound form. For effective and efficient application of the precoated collagen fleece (TachoComb) a modularly constructed applicator (AMISA) was designed that is suitable for a wide range of indications in MIS and allows selective leak closure (SLC) in parenchymatous tissues with different lesions (Pneumothorax, Chylothorax, rupture of liver/spleen, biopsies, fistulae).

Expression of a functional Kir4 family inward rectifier K+ channel from a gene cloned from mouse liver

1. A low stringency polymerase chain reaction (PCR) homology screening procedure was used to probe a mouse liver cDNA library to identify novel inward rectifier K+ channel genes. A single gene (mLV1) was identified that exhibited extensive sequence homology with previously cloned inward rectifier K+ channel genes. The mLV1 gene showed greatest sequence identity with genes belonging to the Kir4 subfamily. The amino acid sequence of mLV1 was 96 % identical to a Kir channel cloned from human kidney (hKir4.2), and approximately 60 % identical to the Kir4.1 channel cloned from human and rat, so that mLV1 was classified as mKir4.2. 2. Xenopus oocytes injected with cRNA encoding mKir4.2 displayed a large inwardly rectifying K+ current, while control oocytes injected with H2O displayed no similar K+ current. The current was blocked by Ba2+ and Cs+ in a voltage-dependent fashion and displayed inward rectification that was intermediate between that of the strong inward rectifier Kir2.1 and the weak inward rectifier Kir1.1. The current was weakly blocked by TEA in a voltage-independent fashion. 3. mKir4.2 current was subject to modulation by several distinct mechanisms. Intracellular acidification decreased mKir4.2 current in a reversible fashion, while activation of protein kinase C decreased mKir4.2 current in a manner that was not rapidly reversible. Incubation of oocytes in elevated [K+] produced a slowly developing enhancement of current. 4. Oocytes co-injected with cRNA for mKir4.2 and Kir5.1, a protein that does not form functional homomeric channels, displayed membrane currents with properties distinct from those expressing mKir4.2 alone. Co-injected oocytes displayed larger currents than mKir4.2, with novel kinetic properties and an increased sensitivity to Ba2+ block at negative potentials, suggesting that mKir4.2 forms functional heteromultimeric channels with Kir5.1, as has been shown for Kir4.1 5. These results demonstrate for the first time that a Kir4.2 channel gene product forms functional channels in Xenopus oocytes, that these Kir channels display novel properties, and that Kir4.2 subunits may be responsible for physiological modulation of functional Kir channels.

Synthesis of an N-glucoasparagine analog as a building block for a V3-loop glycopeptide from gp120 of HIV-I

The preparative synthesis of a new N4-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine mimetic 1, starting from 2-amino-1,5-anhydro-2-deoxy-glucitol hydrochloride and Z-Asp-(OH)-OBn is described. This glycosyl-amino acid unit 1 is expected to show higher stabilities towards in vivo conditions. Further, the use of 1 as building block for the synthesis of modified glycopeptides using solid phase support is reported. The glycopeptide Ac-SXNTRKSIHIGPGRAF-NH2 having sugar-modified Asn2 mimics parts of the V3-loop structure containing the principle neutralizing determinant (PND) of HIV-1 and the naturally conserved glycosylation site within the V3 loop.

Gastrectomy osteopenia in the rat: the role of vitamin B12 deficiency and the type of reconstruction of the digestive tract

1. The mechanisms underlying gastrectomy osteopenia are not yet clear. The gastrectomy-associated cobalamin (vitamin B12) deficiency may favour osteopenia and skeletal fractures. Also, the exclusion of the duodenum from the food passage may contribute to gastrectomy osteopenia. To investigate this, rats were gastrectomized and the passage of nutrients restored either with the duodenum excluded (Roux Y) or included (Longmire). Sham-operated rats served as controls. In half of the rats in each gastrectomy group the serum B12 levels were normalized by parenteral administration of B12.2. Four months post operation, both gastrectomy groups showed a similar degree of osteopenia. There was normal bone mineralization; serum levels of parathyroid hormone were normal, but decreased for 25-hydroxyvitamin D, and elevated for 1,25-dihydroxyvitamin D; in urine there was decreased pH and excessive hyperphosphaturia.3.B12 therapy had no influence on any of the essential bone and mineral metabolic parameters.4. We conclude that osteopenia in the gastrectomized rat (i) is not due to B12 or folic acid deficiency, calcium deficiency or secondary hyperparathyroidism; (ii) is independent of the type of anatomic reconstruction of the digestive tract; (iii) appears to be related to disturbed vitamin D, phosphorus and acid-base metabolism.

Gastric fundectomy in the rat: effects on mineral and bone metabolism, with emphasis on the gastrin-calcitonin-parathyroid hormone-vitamin D axis

In humans, gastric surgery results in in osteopenia via mechanisms that are insufficiently understood; surgery-induced changes in the hormonal axes involving the stomach, thyroid, and the parathyroids may play a role. To study this in more detail, we evaluated calcium (Ca), magnesium (Mg), and phosphorus (P) metabolism as well as physical, chemical, and histomorphometric bone parameters in rats rendered hypergastrinemic by fundectomy (FX). In independent experiments, the response to an oral Ca challenge was investigated in intact rats versus FX, and in thyroidectomized versus thyroid-intact FX rats. Sixteen weeks following FX, body weight was approximately 80% that of sham-operated controls. In urine, P excretion was elevated fivefold, the pH was significantly decreased, and cAMP excretion was elevated as compared with controls; serum parathyroid hormone (PTH), calcitonin, 25OHD, Ca, Mg, and P were normal; gastrin and 1,25(OH)2D were elevated. On the basis of bone ash mineral content, FX rats developed significant osteopenia, and histomorphometry indicated only slightly elevated bone turnover and mineralization. Following oral Ca, thyroid-intact FX rats developed hypercalcemia, serum gastrin decreased, and calcitonin increased significantly; in thyroidectomized FX rats, calcitonin remained at baseline levels although there was a similar degree of hypercalcemia; PTH decreased during the hypercalcemic period in both groups. Serum gastrin did not correlate with calcitonin or PTH, and in multivariate regression analysis the only predictor of serum 1, 25(OH)2D was urinary phosphorus. It was concluded that in the FX rat (1) osteopenia is not caused by intestinal Ca malabsorption, vitamin D, Ca deficiency, or secondary hyperparathyroidism; (2) osteopenia may be related to PTH-independent urinary hyperexcretion of P, followed by a rise of serum 1,25(OH)2D; (3) the existence of endocrine axes among gastrin, calcitonin, and PTH cannot be substantiated. FX osteopenia appears to be related to gastric acid abolition, and the reactive hypergastrinemia probably stabilizes the mass and turnover of bone.

Treatment of malnutrition with 1.1% amino acid peritoneal dialysis solution: results of a multicenter outpatient study

A peritoneal dialysis (PD) solution containing 1.1% amino acids as the osmotic agent was evaluated in a 3-month randomized, prospective, open-label study in malnourished PD patients. Patients in the treatment group (DAA) received one or two exchanges daily with the amino acid solution, depending on tolerance, in place of glucose solutions. Controls (DD) received their usual therapy with glucose dialysate. Fifty-four DAA and 51 DD patients completed the study. In DAA, but not in DD patients, there was a significant increase at month 3 in serum insulin-like growth factor-1 (IGF-1) levels and significant decreases in serum potassium (all 3 months) and inorganic phosphorus levels (months 1 and 3), indicating a general anabolic response. Prealbumin and transferrin levels were significantly increased in DAA but not in DD patients at month 1, but the groups did not differ at months 2 and 3. In patients with baseline albumin levels less than 3.5 g/dL (bromcresol green [BCG] method), DAA patients showed increases in albumin, transferrin (months 1 and 2), and prealbumin levels (all 3 months) relative to baseline values, whereas these serum protein levels were unchanged in DD patients, although the changes from baseline did not differ between groups. In this subgroup, midarm muscle circumference (MAMC) did not change in DD or DAA patients. In patients with baseline albumin levels of 3.5 g/dL or greater, DD patients had decreases in albumin and total protein levels at all 3 months and in prealbumin levels at months 1 and 2, relative to baseline. In DAA patients, there were fewer changes in serum proteins. MAMC increased significantly from baseline in DAA but not in DD patients, although changes from baseline did not differ between DAA and DD groups. DAA patients showed no changes in peritoneal membrane transport characteristics. The results indicate that treatment with one or two exchanges daily of this amino acid-based PD solution is safe and provides nutritional benefit for malnourished PD patients.

The muskrat (Ondatra zibethicus) as a new reservoir for puumala-like hantavirus strains in Europe

We have used an indirect immunofluorescent assay (IFA) and reverse transcription-PCR (RT-PCR) to screen the sera and tissues of muskrats (Ondatra zibethica) caught in the northwest of Brandenburg and in the northeast of Saxony-Anhalt, Germany, for hantavirus infection. Kidney and/or lung tissue from 6 (3.1%, CI = 1.1-6.5%) out of 197 muskrats were found to be positive for genomic sequences of hantavirus by RT-PCR. We could also demonstrate that 14 (5%, CI = 2.9-8.7%) out of 266 muskrat's sera available for testing contained hantavirus-specific antibodies in IFA. Thus, a total of 8% of the investigated muskrat population was found to be positive for hantavirus infection by RT-PCR and IFA. None of the animals was found positive in both tests. Further analysis of the RT-PCR amplified fragments by genomic sequencing revealed sequences mostly related to the puumala (PUU) S segment sequence of the Hällnäs B1 hantavirus strain (97-99% similarity). Our data therefore demonstrate that Ondatra zibethicus serves as an additional reservoir for puumala-like hantavirus strains in Europe. The epidemiological implications of this finding for hantavirus infection in Europe and elsewhere are discussed.

The quality of life in end stage renal disease care

The improved prognosis and survival statistics of both renal transplantation and dialysis have focused attention on the quality of life offered by these treatments. Using a standardized questionnaire, we assessed the quality of life of 612 patients undergoing renal replacement therapy at our center. Of these patients, 359 had been transplanted and 253 patients were on dialysis. Concerning the sociodemographic data, only the time on specific treatment was longer in dialysis patients than in transplanted patients (49.2 versus 55.6 months, P < 0.05). Most complaints were more common in dialysis patients than in transplanted patients. Only the side effects of medication were seen more in transplanted patients (P < 0.005). Life satisfaction was higher in transplanted patients than in dialysis patients. Dialysis patients were more anxious (P < 0.05) and more depressed (P < 0.001) than transplanted patients. Transplanted patients also felt that they had more social support than did dialysis patients. Overall life quality was almost equal between patients on hemodialysis and patients on peritoneal dialysis, and between patients on the waiting list for transplantation and those not on the waiting list. Despite a significantly better quality of life after renal transplantation, the percentage of patients working remained unchanged. (57.5% versus 57.8%, P = n.s.). We conclude that despite an improved quality of life after renal transplantation, these patients are economically not more productive than patients on dialysis.

Protective effect of flavonoids and tocopherol in high altitude hypoxia in the rat: comparison with ascorbic acid

The mixture of flavonoids (silymarin) from Carduus Marianus (0.9 mg.g-1 body weight) and/or ascorbic acid (0.4 mg.g-1 body weight) were administered in the food to 21 day-old (b.w. 35-45 g) rats for one week. Then the animals were exposed, in a hypobaric chamber, to simulated altitude 8,000-12,000 m for one hour. Mean lethal altitude was calculated by the Behrens equation: it was 10,150 m in controls, 10,550 m in ascorbic acid treated, 10,500 m in silymarin and tocopherol treated and 10,450 m in animals, receiving both ascorbic acid and silymarin. Thus silymarin protected the animals against lethality of high-altitude hypoxia. The effect of ascorbic acid and silymarin were not additive.

Volume measurements of localized hepatic lesions using three-dimensional sonography in comparison with three-dimensional computed tomography

Three-dimensional (3D) sonography represents a further development of non-invasive, diagnostic sonographic imaging techniques. The clinical use of this technique in the hepatobiliary system reveals its possible applications, especially in the case of localized lesions. The goal of this study was to evaluate the accuracy of in vivo, three-dimensional ultrasonography with a freely moveable transducer as compared with a computerized tomographic arterial portography using the spiral technique (S-CTAP). A total of 42 patients with localized hepatic lesions (1.5 to 1231 cm3, mean 155 cm3) standard deviation (SD) 231 cm3 were examined using conventional (2D) and 3D ultrasonography (US). Eleven of these patients additionally underwent spiral CTAP. The volumes were calculated using the ellipsoid formula (2D US and 3D US) and were also reconstructed planimetrically with the aid of work stations (3D US and 3D CT). Furthermore, the intra and inter-investigator variability of the 3D planimetry was determined. The conformity of US methods with those using S-CTAP was determined with Bland and Altman s limits of agreement. Inter-rater agreement was calculated using Cohen s concordance index kappa. The deviation of 2D US from 3D CT was -62% to +68% and that of 3D US (ellipsoid) from 3D CT was -28% to +9%. Between 3D US (planimetry) and S-CTAP the deviation was -21% to 9%. The kappa value was 0.886. The intra-investigator variability was 5%. Our results show that the planimetric 3D US is independent of the investigator and, with regard to the volume determinations, is substantially more accurate than measurements with conventional sonography and comparable with those measurements made using CT investigations. 3D sonography may be applied complementarily to CT as an economical procedure for the follow-up of tumor disease.