Glycated and carbamylated albumin are more "nephrotoxic" than unmodified albumin in the amphibian kidney.

There is increasing evidence that proteins in tubular fluid are "nephrotoxic." In vivo it is difficult to study protein loading of tubular epithelial cells in isolation, i.e., without concomitant glomerular damage or changes of renal hemodynamics, etc. Recently, a unique amphibian model has been described which takes advantage of the special anatomy of the amphibian kidney in which a subset of nephrons drains the peritoneal cavity (open nephrons) so that intraperitoneal injection of protein selectively causes protein storage in and peritubular fibrosis around open but not around closed tubules. There is an ongoing debate as to what degree albumin per se is nephrotoxic and whether modification of albumin alters its nephrotoxicity. We tested the hypothesis that carbamylation and glycation render albumin more nephrotoxic compared with native albumin and alternative albumin modifications, e.g., lipid oxidation and lipid depletion. Preparations of native and modified albumin were injected into the axolotl peritoneum. The kidneys were retrieved after 10 days and studied by light microscopy as well as by immunohistochemistry [transforming growth factor (TGF)-ß, PDGF, NF-κB, collagen I and IV, RAGE], nonradioactive in situ hybridization, and Western blotting. Two investigators unaware of the animal groups evaluated and scored renal histology. Compared with unmodified albumin, glycated and carbamylated albumin caused more pronounced protein storage. After no more than 10 days, selective peritubular fibrosis was seen around nephrons draining the peritoneal cavity (open nephrons), but not around closed nephrons. Additionally, more intense expression of RAGE, NF-κB, as well as PDGF, TGF-ß, EGF, ET-1, and others was noted by histochemistry and confirmed by RT-PCR for fibronectin and TGF-ß as well as nonradioactive in situ hybridization for TGF-ß and fibronectin. The data indicate that carbamylation and glycation increase the capacity of albumin to cause tubular cell damage and peritubular fibrosis.

Treatment of an asymptomatic penetrating aortic ulcer in a young patient.

We want to report and discuss the indication for open surgery for an asymptomatic penetrating aortic ulcer (PAU) in the era of thoracic endovascular aortic repair (TEVAR). A 31-year-old female presented with the diagnosis of an aneurysm in the distal aortic arch. With respect to the patients young age, the controversial status of connective tissue disorders and in the absence of concomitant disease, open repair was indicated. There was no proof of a mycotic plaque or connective tissue disease in the microbiological-, pathological analysis and at electron-microscopy. The patient was discharged on the thirteenth postoperative day. In spite of good preliminary results of TEVAR in PAU, in selective cases there is still an indication for open surgery.

Fourier transform mass spectrometry.

Fourier transform mass spectrometry will play an important role in the future because of its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. These features have already found application in gas chromatography-mass spectrometry, multiphoton ionization, laser desorption, and secondary ion mass spectrometry. However, its most notable feature is the ability to store ions. This characteristic, when combined with the others, will allow expeditious study of the interaction of gas-phase ions with both photons (photodissociation) and neutral molecules, and the convenient application of this fundamental information for chemical analysis.

Tetrachlorodibenzo-p-dioxin quantitation in stack-collected coal fly ash.

Gas chromatography-high resolution mass spectrometry has been used to quantitate tetrachlorodibenzo-p-dioxin (TCDD) in fly ash collected from the stack of a typical commercial coal-fired power plant. No TCDD was detected in this fly ash, but minute traces may be present below the detection limit of 1.2 parts per trillion (by weight). This finding indicates that this type of fossil-fueled power plant is not a large source of this compound in environmental samples, in contrast to the conclusions presented in a recent industrial report.

Renal toxicity mediated by glucose degradation products in a rat model of advanced renal failure.

BACKGROUND: In peritoneal dialysis (PD) residual renal function contributes to improved patient survival and quality of life. Glucose degradation products (GDP) generated by heat sterilization of PD fluids do not only impair the peritoneal membrane, but also appear in the systemic circulation with the potential for organ toxicity. Here we show that in a rat model of advanced renal failure, GDP affect the structure and function of the remnant kidney. MATERIALS AND METHODS: Sprague-Dawley rats were randomly assigned to a two stage subtotal nephrectomy (SNX) or sham operation and were left untreated for 3 weeks. The SNX + GDP group continuously received chemically defined GDP intravenously for 4 weeks; the SNX and the sham-operated rats remained without GDP. The complete follow-up for all groups was 7 weeks postoperatively. We analysed renal damage using urinary albumin excretion as well as a semiquantitative score for glomerulosclerosis and tubulointerstitial damage, as well as for immunohistochemical analyses. RESULTS: The SNX + GDP rats developed significantly more albuminuria and showed a significantly higher score of glomerulosclerosis index (GSI) and tubulointerstitial damage index (TII) as compared to SNX or control rats. In the SNX + GDP group the expression of carboxymethyllysine and methylglyoxal was significantly higher in the tubulointerstitium and the glomeruli compared to the SNX rats. Caspase 3 staining and TUNEL assay were more pronounced in the tubulointerstitium and the glomeruli of the SNX + GDP group. In SNX + GDP animals, the expression of the slit diaphragm protein nephrin, was significantly lower compared to SNX or control animals. CONCLUSION: In summary, our data suggests that GDP can significantly advance chronic kidney disease and argues that PD solutions containing high GDP might deteriorate residual renal function in PD.

An unusual cause of peripheral artery embolism: floating thrombus of the thoracic aorta surgically removed.

Intraluminal mobile thrombus of the descending aorta are rare disorders. They are at high risk for peripheral embolism and therefore indication for treatment is mandatory. We report on a 54-year-old patient with peripheral arterial embolization who was treated by surgical thrombus removement by thoracotomy and staged peripheral bypass grafting. New diagnostic tools are presented, therapy and prognosis are discussed.

N-acetylgalactosamine glycosylation of MUC1 tandem repeat peptides by pancreatic tumor cell extracts.

Synthetic peptides corresponding to the human mucin MUC1 tandem repeat domain (20 residues) were glycosylated in vitro by using UDP-N-[3H]acetyl-D-galactosamine (GalNAc) and lysates of pancreatic tumor cell lines. Results obtained with peptides of different lengths (from one to five repeats) suggest that increasing the number of tandem repeats has neither a positive nor a negative effect on the density of glycosylation along the MUC1 tandem repeat protein backbone. Purified glycopeptides were sequenced on a gas-phase sequencer, and glycosylated positions were determined by measuring the incorporated radioactivity in fractions collected following each round of Edman degradation. The results showed that two of three threonine residues on the MUC1 tandem repeat peptides were glycosylated by pancreatic tumor cell lysates at the following positons: GVTSAPDTRPAPGSTAPPAH (underlined T indicates position of GalNAc attachment). None of the serine residues were glycosylated. Determination of the mass of the glycopeptides by mass spectrometry confirmed that a maximum of two molecules of GalNAc were covalently linked to each 20-residue repeat unit in the peptides. The data presented here show that acceptor substrate specificity of the UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase detected in lysates of pancreatic and breast tumor cell lines is identical and is limited to some but not all threonines in the MUC1 tandem repeat peptide sequence. The influence of primary amino acid sequence on acceptor substrate activity was evaluated by using several peptides that contain single or double amino acid substitutions (relative to the native human MUC1 sequence). These included substitutions in the residues that were glycosylated and substitutions of the surrounding primary amino acid sequence. The results of these studies suggest that primary amino acid sequence, length, and relative position of the residue to be glycosylated dramatically affect the ability of peptides to serve as acceptor substrates for the UDP-GalNAc:polypeptide N-acetylgalatosaminyltransferase.

Effect of smoking cessation counseling within a randomised study on early detection of lung cancer in Germany.

INTRODUCTION: In the German lung cancer screening trial LUSI, smoking cessation counseling (SCC) was offered to all participants at time of randomization, and smoking habits were asked for within annual questionnaire inquiries. We analyzed the smoking habits of the participants within the first 2 years of follow-up and especially the potential effect of the SCC on these habits. MATERIALS AND METHODS: We used the smoking data of the initial inquiry on which the decision on invitation to the study was based, the socio-economic data of the questionnaire filled-in at time of randomization, the psycho-social data obtained during the SCC, and the annual questionnaire data of the first two annual follow-up screening rounds. RESULTS: Smoking prevalence decreased in the entire cohort significantly by 4 %, whereby the decrease was with 4.5 % statistically not significantly higher in the control arm than in the screening arm with 3.4 %. The decline was much stronger in the subgroup of attendees to stop-smoking counseling and mounted up therein to 10 %. In some participants, an increase of readiness to quit smoking was observed during the counseling hour, but did not show effects on smoking status 2 years later. DISCUSSION: We did not see a tendency to increased smoking among participants of the intervention arm or the entire study. The decline of smoking prevalence among the attendees of the counseling might be due to self-selection. Since the issue of effectiveness of smoking cessation counseling is important, further research with randomization into offering counseling or no intervention should be taken into consideration.

Evidence that a burst of DNA depurination in SENCAR mouse skin induces error-prone repair and forms mutations in the H-ras gene.

Treatment of SENCAR mouse skin with dibenzo[a,l]pyrene results in abundant formation of abasic sites that undergo error-prone excision repair, forming oncogenic H-ras mutations in the early preneoplastic period. To examine whether the abundance of abasic sites causes repair infidelity, we treated SENCAR mouse skin with estradiol-3,4-quinone (E(2)-3,4-Q) and determined adduct levels 1 h after treatment, as well as mutation spectra in the H-ras gene between 6 h and 3 days after treatment. E(2)-3,4-Q formed predominantly (> or =99%) the rapidly-depurinating 4-hydroxy estradiol (4-OHE(2))-1-N3Ade adduct and the slower-depurinating 4-OHE(2)-1-N7Gua adduct. Between 6 h and 3 days, E(2)-3,4-Q induced abundant A to G mutations in H-ras DNA, frequently in the context of a 3'-G residue. Using a T.G-DNA glycosylase (TDG)-PCR assay, we determined that the early A to G mutations (6 and 12 h) were in the form of G.T heteroduplexes, suggesting misrepair at A-specific depurination sites. Since G-specific mutations were infrequent in the spectra, it appears that the slow rate of depurination of the N7Gua adducts during active repair may not generate a threshold level of G-specific abasic sites to affect repair fidelity. These results also suggest that E(2)-3,4-Q, a suspected endogenous carcinogen, is a genotoxic compound and could cause mutations.

Randomized Study on Early Detection of Lung Cancer with MSCT in Germany: Results of the First 3 Years of Follow-up After Randomization.

INTRODUCTION: The German Lung Cancer Screening Intervention Trial (LUSI) is one of the European randomized trials investigating the efficacy of low-dose multislice computed tomography (MSCT) as a screening tool for lung cancer. In the evaluation of the first (prevalence) screening round, we observed exceptionally high early recall rates, which made the routine application of MSCT screening questionable. Because screening may behave differently in subsequent (incidence) screening rounds, we analyzed (a) basic characteristics for the annual rounds 2 to 4, which have now also been completed, and (b) the first 3 years with complete follow-up since time of randomization. METHODS: Data material was the data record of LUSI after the fourth screening round and the 3-year follow-up had been completed. Basic characteristics of screening, e.g., early recall rate, detection rate, and interval cancers as well of proportion of advanced cancers, were descriptively evaluated and, if informative, group differences were tested for statistical significance. RESULTS: Early recall rates were significantly lower in the subsequent screening rounds than in the first one if the MSCT information from the previous screening rounds was available. Detection and biopsy rates were approximately 1% or lower, ratio of benign:malignant biopsies: 1:1.6 to 1:3. CONCLUSION: Our recent data may not only settle one concern regarding high recall rates in routine MSCT screening but also indicate that screening must be strictly organized to be effective. Performance indicators are similar to those in mammography screening. Nevertheless, possible consequences for the participants (diagnostic workup of suspicious findings, biopsies) are more invasive than in mammography screening.

Effect of captopril on 99mTc-diethylenetriaminepentaacetic acid renograms in two-kidney, one clip hypertension.

In an effort to improve on the noninvasive detection of renal artery stenosis, we investigated the effect of angiotensin converting enzyme inhibition on computer-assisted 99mTc-diethylenetriaminepentaacetic acid (DTPA) renal flow studies in a canine model of two-kidney, one clip hypertension and compared these findings with clearances of inulin and p-aminohippuric acid in the stenotic and contralateral kidney before and after converting enzyme inhibition. The 99mTc-DTPA renal flow study with the converting enzyme inhibitor captopril (1.5 mg/kg bolus with 1.5 mg/min infusion) showed an increased sensitivity in the detection of unilateral renal artery stenosis over the use of the 99mTc-DTPA study alone. Captopril induced striking alterations that were most evident in the 15-minute 99mTc-DTPA renal flow study, in which all nine curves exhibited severely blunted uptake and excretion of the radionuclide. These changes were reversed during a recovery study without converting enzyme inhibition and were not seen when blood pressure was lowered with nitroprusside to a level similar to that observed during converting enzyme inhibition. The changes shown by the 99mTc-DTPA study during converting enzyme inhibition correlated with a decrease in the glomerular filtration rate of the stenotic kidney. Captopril infusion significantly decreased the glomerular filtration rate of the stenotic kidney (16.0 +/- 3.1 vs 11.0 +/- 2.5 mg/min, p less than 0.03) but not of the contralateral kidney (32.4 +/- 2.6 vs 28.4 +/- 2.8 mg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Ceftizoxime elimination kinetics in continuous ambulatory peritoneal dialysis.

We investigated the kinetics of ceftizoxime, a beta-lactamase stable cephalosporin, in eight subjects undergoing continuous ambulatory peritoneal dialysis (CAPD). A single 500-mg or 1-gm dose was injected IV, or a 500-mg dose was given intraperitoneally in the CAPD fluid during a 6-hr dwell time. The ceftizoxime (500 mg) serum kinetic parameters were as follows: peak concentrations, 21 to 46 mg/l; volume of distribution, 0.27 l/kg; elimination rate constant, 0.0784 hr-1; plasma clearance, 1.66 l/kg hr-1; and t1/2, 10.2 hr. The t1/2 after 1 gm was 12 hr. Dialysate ceftizoxime concentrations rose rapidly between 0.25 and 2 hr and slowly over the next 4 hr, but only 4.04 +/- 1.8 and 7.4 +/- 2.9 mg ceftizoxime/hr was eliminated by the peritoneal route over a 6-hr dwell time after 500 mg or 1 gm IV. This represents only 4% to 5% of the dose. After intraperitoneal instillation, the antibiotic appeared in the serum within 15 min in all four subjects, and the peak serum concentrations ranged from 12 to 19.8 mg/l (mean +/- SD = 16.4 +/- 3.3) between 5 and 6 hr. Approximately 78% of ceftizoxime was absorbed from the peritoneal dialysis fluid during a single 6-hr dwell time. Rate constant for absorption, ka, was 0.3959 hr-1 and absorption t1/2 was 1.75 hr (as calculated by the residual equation). These data suggest that ceftizoxime has bidirectional exchange characteristics through the peritoneal membrane. Instillation of ceftizoxime in CAPD fluid alone may permit rapid absorption to reach therapeutic serum concentrations.

Primary embryonal rhabdomyosarcoma of long bone. Case report and review of the literature.

We report a case of primary embryonal rhabdomyosarcoma of long bone, presenting as a lytic destructive bone tumor in the right femoral diaphysis of a 7-year-old girl. To our knowledge, this is only the third report of this entity. The neoplasm was a pure embryonal rhabdomyosarcoma with numerous rhabdomyoblasts. Immunohistochemistry confirmed the diagnosis: The cells were reactive with antibodies directed against desmin, muscle-specific actin, and myoglobin. No other neoplastic mesenchymal component was present within the tumor. Although rare, primary rhabdomyosarcoma, along with Ewing's tumor and osteosarcoma, should be considered in the differential diagnosis of malignant bone tumors in childhood.

Technetium-99m DTPA renal flow studies in Goldblatt hypertension.

Computer-assisted dynamic renal studies were performed on a group of 14 mongrel dogs before and after the induction of unilateral renal artery stenosis. Ninety-second technetium-99m diethylenetriaminepentaacetic acid ( [99mTc]DTPA), 15-min [99mTc]DTPA, and 30-min iodine-131 orthoiodohippurate ( [131I]hippuran) time-activity curves were analyzed and correlated with reduction of renal blood flow as measured by electromagnetic flow probe and PAH clearance techniques. Parameters of the 90-sec [99mTc]DTPA curves found to be significantly different for the same kidney before and after stenosis were: upslope, curve width at 75% maximum, maximum activity value, and differential (stenotic/contralateral) maximum activity ratio. For blood flow reductions greater than 33%, the [99mTc]DTPA studies were judged diagnostic of unilateral renal artery stenosis in all cases, whereas the [131I]hippuran time-activity curves were indicative of stenosis in only six of ten studies. Thus, in this model we find the computer-assisted 90-sec [99mTc]DTPA renal flow study to be superior to conventional [131I]hippuran renography in the diagnosis of moderate-to-severe unilateral renal artery stenosis.

Captopril renography in two kidney and one kidney Goldblatt hypertension in dogs.

In order to improve on the technique of noninvasive detection of renal artery stenosis, we studied the effects of angiotensin converting enzyme inhibition with captopril on individual kidney hemodynamics and function as assessed by technetium-99m diethylenetriaminepentaacetic acid [( 99mTc]DTPA) renal flow studies and iodine-131 orthoiodohippurate [( 131I]hippuran) renography in experimental Goldblatt's hypertension. In two-kidney, one-clip (renin-dependent) hypertension, captopril (1.5 mg/kg bolus with 1.5 mg/min infusion) reduced mean arterial pressure (MAP) and ipsilateral glomerular filtration rate (GFR) without changes in the contralateral kidney. Captopril infusion resulted in alterations in both the [99mTc]DTPA and [131I]hippuran studies, which were most evident in the 15-min [99mTc]DTPA renal flow studies. In one-kidney, one-clip (volume-dependent) hypertension, captopril reduced MAP but did not alter GFR, renal plasma flow, or the radionuclide studies. These studies suggest that the [99mTc]DTPA renal flow study coupled with captopril challenge may unmask intrarenal angiotensin II-dependent functional and hemodynamic changes of the stenotic kidney, and offers promise in the detection of renin-dependent hypertension.

Origins and structures of background ions produced by fast-atom bombardment of glycerol.

Accurate mass measurements were used to assign elemental compositions and tandem mass spectrometry was used to characterize the peak-at-every-mass background ions produced by kiloelectron-volt-particle bombardment of neat fast-atom bombardment matrices. The majority of the background ions observed in the mass spectrum of neat glycerol was identified. On the basis of the experiments with glycerol, a theory for the formation of background ions is presented. Results are discussed according to the chemical and physical changes that ygoe;on-volt-particle bombardment produces in the matrix.

Gas-phase anionic complexes of alkali metal ions and peptides: Structure and collision activated decompositions.

Alkali metal ions and anionic peptides can be desorbed into the gas phase to give metal-bound peptides and bis(peptide) complexes bearing a - 1 charge. Although amide nitrogens of peptide bonds are deprotonated in the gas phase by alkali metal ions, this reacion does not occur in solution. Metal-bound dipeptide anions exist as a single structure, whereas those of tripeptide complexes have three structures as revealed by tandem mass spectrometric studies. Ions of bis(peptide) complexes of alkali metals decompose upon collisional activation principally to form deprotonated peptides, in contrast to bis(peptide) complexes of alkaline earth metal ions, which undergo elimination of a neutral peptide.

High pressure trapping in Fourier transform mass spectrometry: A radiofrequency-only-mode event.

A new event for the Fourier transform mass spectrometry (FTMS) sequence is developed and demonstrated. During this event, called a radiofrequency (RF)-only mode event, the typical passive cubic trap of a Fourier transform mass spectrometer is made to operate as an active quadrupole ion trap. The transition between active and passive modes is developed so that ion loss as a consequence of the transition can be held to 15% or less. The adduct of the ion-molecule reaction of the 1,3-butadiene radical cation and methyl vinyl ether was detected during the Rf-only-mode event at a helium pressure of ∼1×10(-3) torr even though this adduct is not detectable under standard FTMS operating conditions.

Gas-phase base-catalyzed Claisen-Schmidt reactions of the acetone enolate anion with various para-substituted benzaldehydes.

Substituent effects were determined for the gas-phase base-catalyzed Claisen-Schmidt reaction of the acetone enolate anion and various para-substituted benzaldehydes. Under chemical ionization conditions, the adduct for the reaction was detected and the fraction of adduct that is tetrahedral was determined. The Hammett constants for the substituents correlate the fraction of the adduct population that is tetrahedral. The fraction of tetrahedral intermediate is greatest for those systems in which the negative charge is most highly stabilized. The structures of the adducts are determined on the basis of collisionally activated decomposition mass spectra. These spectra show that both the adducts of the ion-molecule reactions and deprotonated reference compounds, which have a structure that is similar to the tetrahedral intermediate, decompose by elimination of water and by a retro-aldol reaction. The adducts formed from the ion-molecule reactions show a greater propensity to reform the acetone enolate, whereas the deprotonated reference compounds eliminate H2O readily. The reaction constant ρ from the Hammett correlation is +1.6, which substantiates that the production of tetrahedral intermediates is facilitated by electron-withdrawing substituents.

Complexes of iron(II) with cysteine-containing peptides in the gas phase.

Gas-phase interactions of peptides that contain cysteine with iron(II) atoms were examined by using fast-atom bombardment and tandem mass spectrometry. Specific and strong interactions of iron and sulfur from the thiol group of the cysteine side chain occur in the gas phase and are the basis for highly specific fragmentation to give abundant [a n -(+) ions. For peptides that contain two cysteines, an internal ion, which results from the interaction of Fe and both thiol groups, is formed upon collisional activation. The mechanism for the formation of [a n -2H+Fe](+) fragment ions requires the metal to be coordinated at sulfur in close proximity to the site of reaction. Iron-bis(pentapeptide) complexes, which form under the same conditions, decompose predominantly to lose a pentapeptide molecule and, to a lesser extent, to give [a a -2H+Fe](+) ions.