Untersuchungen zum Ampicillin/Sulbactam-Spiegel im bestrahlten Unterkieferknochen bei Patienten mit oralen Plattenepithelkarzinomen

INTRODUCTION

Radiation therapy of the oral and maxillo-facial region increases the risk of an infected osteoradionecrosis (IORN) which is a severe complication. Therefore, perioperative antibiotics for the prophylaxis of ORN is a standard in clinical oncology. The combination therapy of ampicillin and sulbactam (Unacid) promises a good therapeutic and prophylactic outcome.

PATIENTS

We compared the concentration of Unacid in bone and blood specimens of 22 irradiated patients. All patients were irradiated with 39.6 Gy prior to surgery. The specimens were obtained during the operation 3 weeks after the end of the radiation therapy.

RESULTS

The concentration of ampicillin/sulbactam in the blood was 124.9/64.5 microg/ml. The bone specimens showed a concentration of ampicillin/sulbactam of 5.54/1.21 microg/g. The concentration of the antibiotic in the bone was three to four times lower than in non-irradiated patients. Nevertheless, this concentration exceeds the minimum inhibitory concentration for bacteria in the oral cavity such as streptcoccae (MHK90<0.25 microg/ml) or staphylococcae (MHK90=0.12-2.0 microg/ml).

CONCLUSIONS

The results of this study suggest, that Unacid is an effective antibiotic in the prophylaxis of ORN in irradiated patients with head and neck tumors.

DNA helix structure and refinement algorithm: comparison of models for d(CCAGGCm5CTGG) derived from NUCLSQ, TNT and X-PLOR

In an earlier study [Heinemann & Hahn (1992). J. Biol. Chem. 267, 7332-7341], the crystal structure of the double-stranded B-DNA decamer d(CCAGGCm(5)CTGG) was refined with NUCLSQ to R = 17.4% against 3799 2sigma structure amplitudes in the resolution range 8-1.7 A. This structure has now been re-refined against the same diffraction data using either TNT or X-PLOR in order to determine to what extent the resulting DNA conformations would differ and to examine the suitability of these programs for the refinement of oligonucleotide structures. The R value from the NUCLSQ refinement could not be reached with either TNT or X-PLOR, although both programs yield reasonably refined DNA models showing root-mean-square deviations against the NUCLSQ model of the decamer duplex of 0.25 and 0.32 A, respectively. Some derived local structure parameters differ depending on the refinement procedure used. This holds true for several exocyclic torsion angles of the sugar-phosphate backbone, whereas sugar puckers as well as helical and base-pair stacking parameters are only weakly influenced. A subset of 15 solvent sites with low temperature factors is conserved in all three models.

Value of chromoendoscopy and magnification endoscopy in the evaluation of duodenal abnormalities: a prospective, randomized comparison

BACKGROUND AND STUDY AIMS

Endoscopic staining methods are increasingly being used to evaluate lesions in the esophagus and colon. The aim of this prospective study was to investigate chromoendoscopy and magnification endoscopy for the evaluation of mucosal lesions in the duodenum.

PATIENTS AND METHODS

Consecutive patients were randomly assigned to undergo conventional endoscopy without staining (group A) or intravital staining of the duodenal mucosa with indigo carmine and evaluation with a conventional video endoscope (group B) or a magnification endoscope (group C). Visible lesions were characterized before and after staining, and biopsies were taken for histological assessment.

RESULTS

A total of 118 patients was examined. Chromoendoscopy detected significantly more lesions in the duodenal bulb (98 vs. 28; P = 0.0042) in more patients (29 vs. 15; P = 0.0025) compared with conventional endoscopy (group A). After mucosal staining, there was no difference between video endoscopy and magnification endoscopy with regard to the number or extent of the lesions identified. Significantly more targeted biopsies were possible after intravital staining. The most commonly identified lesions on targeted biopsies included (staining/control groups): gastric metaplasia (14/3), hyperplastic Brunner's glands (6/3), inflammatory changes (7/6), villous atrophy (1/3), adenoma (1/0).

CONCLUSIONS

Intravital staining of the duodenum with indigo carmine may be useful for detecting mucosal abnormalities, delineating their extent, and allowing targeted biopsies. Magnification endoscopy, when used in addition to chromoendoscopy, does not appear to further increase the diagnostic yield for detecting duodenal abnormalities.

[Surgery of hemorrhoids using the Long method and its complications]

BACKGROUND

The aim of this article is an assessment of new surgical procedure--stapled hemorroidectomy according to Longo. We do concentrate on surgical complications and possibilities of it's management.

METHODS

Prospective, clinical follow up of patients in which stapled hemorrhoidectomy was performed during the period of 2 years (1st December 2000--30st November 2002). Observation concentrates on surgical complications of this method. All patients had a clinical check up 3 weeks and 3 months after surgery. In case of any problems treatment and follow up continues.

RESULTS

Stapled hemorroidectomy was performed during the period of 2 years in 52 patients (100%). There was 11 patients (21.2%) with some of surgical complication. The most serious one was massive rectal bleeding after surgery, which has been observed in 4 patients (7.6%). Other surgical complications observed in our group were anal stenosis, local infection, acute anal fissure and retention of urine.

CONCLUSION

Stapled hemorroidectomy is now one of feasible alternatives for surgical treatment of hemorrhoids. Serious surgical complications observed in our patients were bleeding from the stapled suture line and anal stenosis. The aim of this article is to refer possible surgical complications of this method, it's prevention and management.

[Ceftriaxone versus Levofloxacin for antibiotic therapy in patients with acute cholangitis]

INTRODUCTION

For the therapy of acute cholangitis complete biliary drainage and antibiotic therapy is needed. The aim of the current study was to compare intravenous therapy of acute cholangitis with Ceftriaxone or Levofloxacin in a prospective and randomized fashion.

METHODS

Patients with biliary obstruction and clinical signs of infection received in addition to 1.5 g Metronidazole either 500 mg Levofloxacin/die or 2 g Ceftriaxone/die. Early on during ERCP, bile was aspirated via the cannulation catheter and cultured for bacteria under aerobic and anaerobic conditions. Minimal inhibitory concentrations of the respective antibiotics were determinate for each isolate. The clinical course was followed for at least 6 days with clinical and laboratory data.

RESULTS

60 patients with clinical signs of acute cholangitis were randomised. In 40 patients (66 %) biliary colonization with bacteria could be identified. In all bacterial species Levofloxacin showed significantly lower rates of in-vitro resistance as compared to Ceftriaxone. However, the percentage of patients with a clinical cure or significant improvement was the same in the two groups.

CONCLUSIONS

The clinical effect of Levofloxacin and Ceftriaxone in patients with acute cholangitis showed no significant differences. Because of improved in-vitro efficiency, a calculated therapy with Levofloxacin might be advantageous.

Infrequent genetic alterations of the tumor suppressor gene PTEN/MMAC1 in squamous cell carcinoma of the oral cavity

BACKGROUND

Fifty tumor specimens from primarily untreated patients were analyzed to elucidate the involvement of the tumor suppressor gene PTEN/MMAC1 in the development of oral squamous cell cancer.

METHODS

Eight microsatellite markers, spanning 10 cM of genomic DNA located centromeric, telomeric or intragenic of PTEN/MMAC1 were used for loss of heterozygosity (LOH) and breakpoint analysis. The microsatellite panel within or in close proximity (1 cM) to the 10q23.3 locus showed a LOH rate of 12%. Complete sequence analysis of the genes coding region was performed in all 10 cases that exhibited LOH in one of the eight microsatellite markers within or around the PTEN/MMAC1 gene. Comparative multiplex PCR reactions served to screen for homozygous deletions.

RESULTS

There was no association between allelic loss of the gene, overall patient survival and recurrence-free survival. Sequencing did not reveal any mutation in the coding region of PTEN/MMAC1. Differential PCR analysis failed to detect any homozygous deletion.

CONCLUSIONS

We conclude that PTEN/MMAC1 gene alterations do not play a key role in tumorigenesis of oral squamous cell cancers.

Time independence of the prognostic impact of tumor cell detection in the bone marrow of primary breast cancer patients

PURPOSE

Tumor cell detection (TCD) in bone marrow is an outstanding prognostic factor in breast cancer. There is only one other study that has investigated more than 300 patients with a median follow-up of more than 5 years (J. L. Mansi et al., Lancet, 354:197-202, 1999). We report data from 727 patients with a median follow-up period of 6.5 years.

EXPERIMENTAL DESIGN

In a prospective study, intraoperatively aspirated bone marrow was screened for micrometastatic cancer cells. We used an immunocytological method (monoclonal mucin antibody 2E11; the avidin-biotin complex method).

RESULTS

Forty-three percent of the patients were TCD positive. Sixty percent of the patients with distant metastases were tumor cell positive (155 of 258 patients). Forty-nine percent of the patients with positive TCD developed distant metastases (155 of 315 patients). TCD was an independent prognostic factor for clinical outcome after a median follow-up time of 6.5 years. The prognostic impact of TCD and tumor size remains constant with the time, whereas the impact of grading and progesterone receptor on risk seems to decrease with longer follow-up time.

CONCLUSIONS

TCD remains an independent prognostic factor The impact of TCD does not change with longer follow-up time. TCD is a reliable prognostic factor and provides important information about the process of metastasis.

Chromoendoscopy with indigocarmine improves the detection of adenomatous and nonadenomatous lesions in the colon

BACKGROUND AND STUDY AIMS

Depressed early cancers and flat adenomas have a high potential for malignancy with possible infiltrating growth, despite the small size of the lesion. Japanese investigators have shown that early diagnosis and classification of these lesions is possible with the help of chromoendoscopy. The aim of this study, therefore, was to evaluate the usefulness of chromoendoscopy during routine colonoscopy.

PATIENTS AND METHODS

During routine colonoscopy, vital staining with indigocarmine solution (0.4 %, 1 - 10 ml) was performed on all visible lesions in 100 consecutive patients without visible inflammatory changes. If findings on macroscopic examination were unremarkable, the sigmoid colon and rectum were stained with indigocarmine over a defined segment (0 - 30 cm ab ano) and inspected for lesions visible only after staining. Each lesion was classified with regard to type (polypoid, flat, or depressed), position and size. The staining pattern was classified according to the pit pattern classification.

RESULTS

A total of 52 patients had 105 visible lesions (89 polypoid, 14 flat and two depressed). The mean size of the lesions was 1.4 cm. Among the 48 patients with mucosa of normal appearance, 27 showed 178 lesions after staining (176 flat, two depressed) with a mean size of 3 mm. On histological investigation, 210 lesions showed hyperplastic or inflammatory changes, 67 were adenomas and six were cancers. Use of the pit pattern system to classify lesions (adenomatous, pit patterns III-V; nonadenomatous, pit patterns I-II) was possible, with a sensitivity of 92 % and a specificity of 93 %. Lesions with pit patterns III - V showed higher rates of dysplasia.

CONCLUSIONS

Chromoendoscopy allows easy detection of mucosal lesions in the colon and facilitates visualization of the margins of flat lesions. This technique unmasks multiple mucosal lesions which are not identified by routine video colonoscopy. The pit pattern seen after staining allows differentiation between hyperplastic and adenomatous lesions which may have consequences with regard to the endoscopic interventions needed.

[Interventional ERCP in patients with cholestasis. Degree of biliary bacterial colonization and antibiotic resistance]

Interventional ERCP in patients with cholestasis. Degree of biliary bacterial colonization and antibiotic resistance. Biliary obstruction together with bacterial colonization of the bile duct may lead to development of acute cholangitis. The aim of our prospective study was to investigate the presence and degree of biliary bacterial colonization by means of bile aspiration during ERCP in patients with biliary obstruction. Furthermore, we evaluated antibiotic therapy regimens, which would cover the bacterial species obtained by ERCP and subsequent culture in each patient. In addition, analysis of risk factors was performed that would predispose to the development of cholangitis.80 patients with clinical and laboratory evidence of biliary obstruction underwent ERCP with initial aspiration of bile via the cannulation catheter. This material was used to culture aerobic and anaerobic bacteria and determine the colony count/ml bile, followed by identification of each species and antibiotic resistance testing. The minimal inhibitory concentration for Levofloxacin, Ciprofloxacin, Piperacillin, Ampicillin, Ceftriaxone, Imipenem, Gentamycin und Metronidazole was determined. Immediately after the ERCP or if the body temperature (after ERCP) rose to > 38 degrees C blood cultures were obtained. In 45 (56 %) patients biliary colonization with bacteria could be identified (56 %). In 20 patients a single isolate was cultured, in 25 cases mixed infection was present. A total of 83 species were isolated. The most common bacteria were E. coli, Enterococcus and Klebsiella. 9.6 % of all isolates were obligatory anaerobes. In 9 of 80 patients bloodcultures tested positive for bacterial growth (rate of bacteremia: 11.3 %). 10 patients had acute cholangitis clinically before ERCP, 13 patients developed signs of infection after ERCP. Statistically significant factors contributing to the risk of infection were age of the patient, the clinical condition of the patient before ERCP and the biliary colony count. Patients with development of infection after ERCP showed a significantly higher incidence of bacterial colonization of the biliary tree and a higher colony count. In all bacterial species Imipenem (4.5 %) or Levofloxacin (2.2 %) exhibited the lowest rate of in-vitro resistance. Based on these data, the implementation of Levofloxacin in combination with anaerobic coverage is advantageous as a calculated therapy for patients with acute cholangitis.

Cross-reactive binding of cyclic peptides to an anti-TGFalpha antibody Fab fragment: an X-ray structural and thermodynamic analysis

The monoclonal antibody tAb2 binds the N-terminal sequence of transforming growth factor alpha, VVSHFND. With the help of combinatorial peptide libraries it is possible to find homologous peptides that bind tAb2 with an affinity similar to that of the epitope. The conformational flexibility of short peptides can be constrained by cyclization in order to improve their affinity to the antibody and their stability towards proteolysis. Two cyclic peptides which are cross-reactive binders for tAb2 were selected earlier using combinatorial peptide libraries. One is cyclized by an amide bond between the N-alpha group and the side-chain of the last residue (cyclo-SHFNEYE), and the other by a disulfide bridge (cyclo-CSHFNDYC). The complex structures of tAb2 with the linear epitope peptide VVSHFND and with cyclo-SHFNEYE were determined by X-ray diffraction. Both peptides show a similar conformation and binding pattern in the complex. The linear peptide SHFNEYE does not bind tAb2, but cyclo-SHFNEYE is stabilized in a loop conformation suitable for binding. Hence the cyclization counteracts the exchange of aspartate in the epitope sequence to glutamate. Isothermal titration calorimetry was used to characterize the binding energetics of tAb2 with the two cyclic peptides and the epitope peptide. The binding reactions are enthalpically driven with an unfavorable entropic contribution under all measured conditions. The association reactions are characterized by negative DeltaC(p) changes and by the uptake of one proton per binding site. A putative candidate for proton uptake during binding is the histidine residue in each of the peptides. Hydrogen bonds and the putative formation of an electrostatic pair between the protonated histidine and a carboxy group may contribute markedly to the favorable enthalpy of complex formation. Implications to cyclization of peptides for stabilization are discussed.

Venous leg ulcers and microcirculation

Incompetence of venous valves do not lead per se to trophic skin changes of the lower limb. In severely concerned patients suffering from dermatoliposclerosis or venous leg ulcers retrograde pressure waves were detected in the nutritive capillaries of the skin by the "servo nulling" pressure measurement during simulated calf muscle contraction. Between the degree of trophic skin change and the capillary density and cutaneous oxygen partial pressure a close correlation was found. Healing of venous ulcers occurred only if the cutaneous microangiopathy in the ulcer area improved. Capillary density and transcutaneous oxygen partial pressure were of prognostic impact as to healing of venous ulcers.

Frequency of mediastinal lymph node metastases in patients undergoing EUS evaluation of pancreaticobiliary masses

BACKGROUND

Mediastinal lymph node metastases have rarely been reported in patients with pancreatic cancer. Our aim was to determine the frequency of mediastinal lymph node metastases in patients with pancreaticobiliary masses by using EUS-guided fine needle aspiration.

METHODS

Sixty-six consecutive patients with pancreatobiliary masses were evaluated on EUS for the presence of mediastinal lymph node metastases. All masses were staged by commonly used EUS criteria by using sector scanning echoendoscopes. Mediastinal lymph nodes with EUS features that suggested malignancy were aspirated.

RESULTS

Of the 66 patients (mean age 65.6 years; 38 men), 4 had biliary masses, 5 had lesions of the major duodenal papilla, and 57 had pancreatic masses. Eleven patients (10 pancreatic masses, 1 biliary mass) had enlarged mediastinal lymph node (12-30 mm) on EUS; in 2 patients these had a benign appearance and were not aspirated. Nine patients underwent EUS-guided fine needle aspiration: in 1 the cytology was inconclusive (patient subsequently had a negative Whipple resection); in 4 the mediastinal lymph node cytology was benign; the remaining 4 patients had adenocarcinoma cells in the aspirate from mediastinal lymph node. These 4 pancreatic tumors were staged by EUS as T2N1M1 (1), as T4N0M1 (2, one later found to also have a lung mass), and T4N1M1 (1).

CONCLUSION

Enlarged mediastinal lymph nodes were found on EUS in 16.6% (95% CI [7.7%, 25.6%]) of patients with pancreatobiliary masses and in 17.5% (95% CI [7.6%, 27.4%]) of patients with pancreatic masses. The frequency of mediastinal lymph node metastases in pancreatobiliary masses was 6.1% (95% CI [0.34%, 11.9%]) and in pancreatic masses 7.0% (95% CI [0.4%, 13.6%]). Routine EUS evaluation of the mediastinum in patients with pancreatic masses is warranted.

The Structure of calnexin, an ER chaperone involved in quality control of protein folding

The three-dimensional structure of the lumenal domain of the lectin-like chaperone calnexin determined to 2.9 A resolution reveals an extended 140 A arm inserted into a beta sandwich structure characteristic of legume lectins. The arm is composed of tandem repeats of two proline-rich sequence motifs which interact with one another in a head-to-tail fashion. Identification of the ligand binding site establishes calnexin as a monovalent lectin, providing insight into the mechanism by which the calnexin family of chaperones interacts with monoglucosylated glycoproteins.

Influence of fluorophor dye labels on the migration behavior of polymerase chain reaction--amplified short tandem repeats during denaturing capillary electrophoresis

The determination of the length of polymerase chain reaction (PCR)-amplified short tandem repeats (STRs) by denaturing capillary electrophoresis (CE) is a standard procedure for purposes of genotyping. We show that dye-specific mobility anomalies exist for 5'-fluorophor-labelled single-stranded DNA (ssDNA) fragments in CE using the performance-optimized polymer 4 (POP4) buffer sieving matrix, containing the entangled poly(N,N-dimethylacrylamide) polymer, urea, and 2-pyrrolidinone. The dye-specific retardation effects relative to coseparated GeneScan-500 [TAMRA] standard fragments can lead to wrong genotyping, even for allele-specific fragments of pentanucleotide STRs, when comparing the relative calculated sizes of identical fragments, labelled with rhodamine (ROX, TAMRA) or fluorescein dyes (FAM, 6-FAM, HEX, JOE, NED, TET): The size of fluorescein dye-labelled fragments of appr. 100 b in length appears to be smaller by up to 6.5 b. This effect becomes more dramatic with decreasing size: a 6-FAM-labelled 24-mer oligonucleotide appeared to be smaller by 11 b. In contrast, in classical urea/polyacrylamide slab-gel electrophoresis only a small dye-specific retardation of identical fragments is observed. The dye-specific effects are superimposed by weaker size and sequence-dependent anomalies of fragment mobility. Therefore, in denaturing CE the coseparation of a defined allele ladder labelled with the same dye as the unknown sample fragments remains the method of choice for accurate genotyping.

Signal and nutrient exchange at biotrophic plant-fungus interfaces

Biotrophic interfaces are formed in mutualistic and parasitic plant-fungus interactions. They result from coordinated developmental programs in both partners and represent specialized platforms for the exchange of information and nutritional metabolites. New data on the establishment and the components of functional interfaces have been obtained in a number of ways. First, by isolation of symbiotically defective mutants; second, by characterization of new genes and their products; and, third, by the identification and localization of components of biotrophic interfaces, such as cell-wall proteins, H+-ATPases and nutrient transporters.

Influence of fluorophor dye labels on the migration behavior of polymerase chain reaction--amplified short tandem repeats during denaturing capillary electrophoresis

The determination of the length of polymerase chain reaction (PCR)-amplified short tandem repeats (STRs) by denaturing capillary electrophoresis (CE) is a standard procedure for purposes of genotyping. We show that dye-specific mobility anomalies exist for 5'-fluorophor-labelled single-stranded DNA (ssDNA) fragments in CE using the performance-optimized polymer 4 (POP4) buffer sieving matrix, containing the entangled poly(N,N-dimethylacrylamide) polymer, urea, and 2-pyrrolidinone. The dye-specific retardation effects relative to coseparated GeneScan-500 [TAMRA] standard fragments can lead to wrong genotyping, even for allele-specific fragments of pentanucleotide STRs, when comparing the relative calculated sizes of identical fragments, labelled with rhodamine (ROX, TAMRA) or fluorescein dyes (FAM, 6-FAM, HEX, JOE, NED, TET): The size of fluorescein dye-labelled fragments of appr. 100 b in length appears to be smaller by up to 6.5 b. This effect becomes more dramatic with decreasing size: a 6-FAM-labelled 24-mer oligonucleotide appeared to be smaller by 11 b. In contrast, in classical urea/polyacrylamide slab-gel electrophoresis only a small dye-specific retardation of identical fragments is observed. The dye-specific effects are superimposed by weaker size and sequence-dependent anomalies of fragment mobility. Therefore, in denaturing CE the coseparation of a defined allele ladder labelled with the same dye as the unknown sample fragments remains the method of choice for accurate genotyping.

The role of haustoria in sugar supply during infection of broad bean by the rust fungus Uromyces fabae

Biotrophic plant pathogenic fungi differentiate specialized infection structures within the living cells of their host plants. These haustoria have been linked to nutrient uptake ever since their discovery. We have for the first time to our knowledge shown that the flow of sugars from the host Vicia faba to the rust fungus Uromyces fabae seems to occur largely through the haustorial complex. One of the most abundantly expressed genes in rust haustoria, the expression of which is negligible in other fungal structures, codes for a hexose transporter. Functional expression of the gene termed HXT1 in Saccharomyces cerevisiae and Xenopus laevis oocytes assigned a substrate specificity for D-glucose and D-fructose and indicated a proton symport mechanism. Abs against HXT1p exclusively labeled haustoria in immunofluorescence microscopy and the haustorial plasma membrane in electron microscopy. These results suggest that the fungus concentrates this transporter in haustoria to take advantage of a specialized compartment of the haustorial complex. The extrahaustorial matrix, delimited by the plasma membranes of both host and parasite, constitutes a newly formed apoplastic compartment with qualities distinct from those of the bulk apoplast. This organization might facilitate the competition of the parasite with natural sink organs of the host.

Inter-laboratory comparison of DNA preservation in archival paraffin-embedded human brain tissue from participating centres on four continents

DNA extracted from formalin-fixed and paraffin-embedded brain tissue is known to contain as yet ill-characterized inhibitors of the PCR process. As part of a project that aims to clarify the role of mitochondrial DNA sequence variation in human neurodegenerative diseases using DNA from various ethnic backgrounds, we have investigated factors that influence the preservation of archival DNA and its suitability for PCR. In this study, neuropathological tissue samples were analysed that had been routinely processed in 18 international centres on four continents. Following DNA extraction, PCR amplification of mitochondrial and nuclear DNA sequences was performed with and without additional purification of the template DNA. In addition, the DNA used for PCR was analysed by HPLC. Phosphate-buffered formalin proved to be a superior fixative compared with unbuffered aldehyde: DNA extraction resulted in greater yields, the molecular weight of the isolated DNA was higher and PCR was more successful. PCR inhibitors were identified as (1) high concentrations of small (<300 bp) DNA fragments that competitively compete with template DNA and (2) contaminants of the DNA template solution including denatured protein that cannot be completely removed by phenolic extraction. HPLC analysis did not reveal significant qualitative differences between DNA isolated from fresh-frozen tissue samples and DNA recovered from formalin-fixed, paraffin-embedded brain tissue. The fact that DNA could be amplified from the majority of tissue specimens in this study suggests that rare diseases and diseases where ethnic background plays an important role can be sampled for genetic polymorphism analysis on a global scale using archival neuropathological collections.

Estimating the relapse stage in chronic myeloid leukaemia patients after allogeneic stem cell transplantation by the amount of BCR-ABL fusion transcripts detected using a new real-time polymerase chain reaction method

We have used a new single-step real-time reverse transcription polymerase chain reaction (RT-PCR) method to quantify BCR-ABL transcripts, thereby estimating the relapse stage in chronic myeloid leukaemia patients after allogeneic transplants. In 402 samples from 172 patients, BCR-ABL expression was determined and normalized, using the GAPDH housekeeping gene product as an endogenous reference. In our real-time RT-PCR assay, serial dilutions of RNA of the K562 cell line remained positive down to 7.5 pg. The median normalized BCR-ABL amount differed significantly (P < 0.001) between the various disease stages and was 0.06% (range 0.001-1.55%), 3.2% (range 1.4-5.6%) and 21.5% (range 6.8 -827%) in 17 patients with a molecular relapse, in eight patients with a cytogenetic relapse and in 10 patients with a haematological relapse respectively.

Interaction of cisplatin with methionine- and histidine-containing peptides: competition between backbone binding, macrochelation and peptide cleavage

The pH- and time-dependent reaction of cis-[PtCl2(NH3)2] with the methionine- and histidine-containing peptides H-Gly-Met-OH, H-Gly-Gly-Met-OH, Ac-His-Gly-Met-OH, and Ac-His-(Ala)3-Met-OH at 313 K has been investigated by ion-pairing reverse phase HPLC and NMR spectroscopy. For equimolar solutions (c=0.8 mM, pH approximately equals 3 or 8.8), initial formation of the kinetically favored S-bound complex is followed by relatively rapid metallation of the neighboring methionine amide nitrogen NM to afford a kappa2NM,S six-membered chelate. The strong trans effect of the methionine S then favors facile NH3 substitution, leading to generation of tridentate complexes such as [Pt(H-Gly-MetH(-1)-OH)-kappa3NG,NM,S)(NH3)]+ or [Pt(H-Ac-His-GlyH(-1)-MetH(-1)-OH-kappa3NG,NM,S)(NH3)]. In the case of H-Gly-Gly-Met-OH, this reaction is accompanied by loss of a second NH3 ligand in alkaline solution to generate the tetradentate kappa4NG1,NG2,NM,S species. In contrast, cleavage of the backbone C(O)-N bond to the second metallated amide nitrogen after t>100 h is common to the tridentate complexes of the tri- and pentapeptides at pH<5. Although an imidazole-coordinated kappa2N3H,S macrochelate is formed throughout the whole range 2.5 < or = pH < or = 10 for Ac-His-Gly-Met-OH, it slowly decays (t=10-1000 h) to the thermodynamically more stable tridentate kappa3NG,NM,S complex. All major final products were separated and fully characterized by NMR and MS.

Comparison between Taq DNA Polymerase and Its Stoffel Fragment for Quantitative Real-Time PCR with Hybridization Probes

In quantitative real-time PCR assays, fluorophor-labeled oligonucleotide probes are employed to generate sequence-specific signals for the quantitative evaluation. Whereas TaqMan® probes have to be hydrolyzed during PCR by the endonucleolytic activity of Taq DNA polymerase to generate a signal, the hybridization probes in Light-Cycler® assays must not be hydrolyzed. In this study, we demonstrate for four different targets that the probes are degraded during PCR by Taq DNA polymerase. Signal yield, quality of amplification curves, and accuracy of quantitative measurements can be improved using the Stoffel fragment lacking an endonucleolytic activity and TaqStart® antibody suppressing the formation of nonspecific products, without laborious efforts to optimize the amplification protocol.

[Status of hearing aid use by children in schools for the hearing impaired and deaf]

To evaluate and possibly improve the hearing aid fittings of children attending the Westphalian School for the Hearing Impaired or the Westphalian School for the Deaf, regular pedaudiologic consulting hours were established at both schools. During a 2-year period, 115 children were examined once, 35 children twice, and 5 children three times. The examinations comprised ear microscopy, audiometry, and a check of the hearing aids with a 0.6-cm3 coupler (children up to 7 years) or 2-cm3 coupler, respectively. The following criteria were used to assess the quality of the hearing aid setting: status of the external auditory canal and middle ear, acceptance of wearing the hearing aid, status of the ear mold, technical status of the hearing aid, and its setting. The results were related to four variables: gender, type of school, age, and mean hearing loss. Overall, just 40.9% of all children showed satisfactory hearing aid performance at the first examination and just 37.1% at the second. A significant influence of the variables on the hearing aid performance was documented for hearing loss only. The higher the hearing loss, the more likely the children were to have good hearing aid status. Analysis of the different parameters revealed that an incorrect setting was the main problem, with a rate of 20.9%; the rate of the other parameters varied from 6.1% to 15.7%. Thus, no parameter was of major relevance to the results. The results of the second examination were poorer in most parameters than those of the first. These alarming results, which are probably not only of regional significance, demonstrate that the hearing aid status of children attending schools for the hearing impaired or for the deaf is in urgent need of improvement.

Microcirculatory dysfunction in chronic venous insufficiency (CVI)

The elevated ambulatory pressure in the peripheral venous system of chronic venous insufficiency (CVI) patients manifests itself not only in the form of disturbed macrocirculation but also and particularly in microangiopathic changes. For this reason, it is closely correlated with trophic disorders of the skin and can ultimately lead to ulceration. Using microcirculation research techniques, we are able to provide clear evidence of a typical microangiopathy in chronic venous insufficiency. Fifty CVI in Widmer stages I, II, and III were examined with fluorescence video microscopy, intravital video capillaroscopy, transcutaneous oxygen partial pressure measurement, TcpO2 and laser Doppler flowmetry. The effects of compression therapy with individually fitted compression stockings on capillary morphology were studied over a period of 4 weeks in 20 CVI patients in Widmer stages I and II. The capillary pressure was measured during simulated muscle contraction using a servo-null micropressure system. We periodically drew blood from the dorsalis pedis vein and a brachial vein of 11 healthy test persons and 8 patients with stage III CVI during experimental venous hypertension in order to evaluate the expression pattern of leukocyte adhesion molecules involved in inflammation: LFA-1 (CD11a), Mac-1 (CD11b), p150,95 (CD11c), CD18, VLA-4 (CD49d), and L-selectin (CD62L). In the same patients, we used immunohistochemical methods to examine clinically unaffected skin and the skin near an ulcer, focusing on the adhesion molecules ICAM-1, VCAM-1, and E-selectin. The microangiopathic changes observed with worsening clinical symptoms include a decrease in the number of capillaries, glomerulus-like changes in capillary morphology, a drop in the oxygen content (tcpO2) of the skin, increased permeability of the capillaries to low-molecular-weight substances, increased laser Doppler flux reflecting elevated subcutaneous flow, and diminished vascular reserve. These microangiopathic changes worsen in linear proportion to the clinical severity of chronic venous insufficiency. In patients with venous ulcerations, the baseline expression of LFA-1 and VLA-4 on lymphocytes, Mac-1 expression on the myeloid cell line, and L-selectin expression on all three cell lines was not significantly different form that in healthy controls. During orthostatic stress, there was a significant reduction in the expression of L-selectin in blood cells collected at foot level in the controls (p=0.002), but not in the patients. Clinical improvement by compression therapy was accompanied by an increase in the number of nutritive capillaries, while the diameter of the capillaries and the dermal papillae was reduced. When ulcers healed in a short period (<6 weeks), we observed a concomitant increase in the number of capillaries (p<0.05). Microangiopathy appears before tropic disorders of the skin develop. Even trophically normal skin areas may have dilated nutritive capillaries, an early sign of disturbed skin perfusion. These changes represent a plausible explanation for the development and to recurrency tendency of venous ulcers. The reduced expression of lymphocytic L-selectin in healthy controls during the orthostatic stress test may be an indication that the cells are activated by venous stasis. Clinically effective therapeutic measures improve the impaired microcirculation of the skin in the ankle area.

Structural analysis of high resolution in vitro MR images compared to stained grindings

The recent advancement of high resolution magnetic resonance imaging has opened up new avenues for the determination of structural characteristics of the trabecular network, which may significantly improve the diagnosis of osteoporosis. An analysis of the calcaneus in healthy women has shown similar age-related changes when comparing structural parameters in high resolution MR images and BMD as measured by DXA [1]. Here we undertook an in vitro study to further compare structural measurements in MR images with those from stained grindings. A 3D gradient echo sequence on a 1.5 T scanner was used to obtain four contiguous sagittal MR images with a slice thickness of 1 mm and an in plane pixel size of 195 microns. Twenty-one stained grindings with a slice thickness of 1 micron each were obtained from a 3 mm thick slab of the same volume investigated by MR. The stack of stained grindings was also used to simulate the influence of variations in slice thickness and in plane resolution. Results for structural parameters derived from the high resolution MR images differed considerably from those derived from the stained grindings because the MR images are heavily influenced by partial volume artifacts. This finding was supported by simulations which also revealed that even at a slice thickness of 500 microns and an in plane pixel size of 13 microns, accurate results could not be obtained when a histomorphometric type analysis was applied. Results also depended strongly on the segmentation method. However, contrary to the stained grindings, images averaged over several slices reveal the three-dimensional network character of the trabecular structure. New efforts should be undertaken to develop analysis strategies that are more adequate for in vivo high resolution images instead of using analysis techniques applied in classical histomorphometry.

[Hand-held ultrasound-guided vacuum biopsy of mammary lesions--first experiences]

OBJECTIVE

Evaluation of indications for ultrasound guided hand-held Mammotome-biopsy.

MATERIAL AND METHODS

To achieve breast diagnosis 50 ultrasound guided hand-held Mammotome-biopsies were performed between January 3rd and April 4th, 2000.

RESULTS

34 patients presented with non-palpable, 16 with palpable breast lesions. The benign-to-malignant ratio was 80% to 20%. Complete removal of the lesion we established in 22 (44%) of all 50 procedures. Definitive breast diagnosis of malignancies was achieved in all but one case.

CONCLUSIONS

We regard the ultrasound guided hand-held Mammotome-biopsy as diagnostic and surgical instrument that provides the clinician with a flexible and easy to use method of accurate breast diagnosis. Lesions too small, superficial, or deep for conventional core biopsy are indications for a ultrasound guided Mammotome-biopsy as well as abnormalities where wide sampling is considered important or small fibroadenomas. However, standard of care for breast diagnosis remains the conventional hand-held 14-gauge-core-biopsy. For malignant lesions hand held mammotomy must be regarded as a diagnostic and not a therapeutic procedure.

The effect of extracorporeal shock waves on joint cartilage--an in vivo study in rabbits

The application of extracorporeal shock waves has become a new mode of treatment for affections of the locomotor apparatus such as calcifying tendinitis, epicondylitis humeri radialis, calcaneodynia and pseudarthrosis. The treatment often takes place in the vicinity of joints. Up to now no systematic data have been published about possible side-effects on joint cartilage. In an in vivo study the effect of extracorporeal shock waves on joint cartilage was evaluated in 24 immature New Zealand White rabbits. The left lateral femoral condyle of each animal was treated with 2000 shock waves of 1.2 mJ/mm2; the right condyle served as control. Macroscopical, radiological and histological analysis at 0, 3, 12 and 24 weeks after treatment showed no pathological changes in the joint cartilage. We conclude that extracorporeal shock wave treatment does not cause damage to the joint cartilage of growing rabbits.

The influence of hypothermia on outer hair cells of the cochlea and its efferents

Transient evoked otoacoustic emissions (TEOAE) were recorded in 21 guinea-pigs undergoing hypothermia. The minimal average body temperature during cooling was 26 degrees C/24.9 degrees C measured orally or rectally, respectively. The animals were subsequently warmed to normal body temperature. A clear influence of body temperature on TEOAE could be documented. During cooling the amplitude and reproducibilities decreased, disappearing completely at a mean temperature below 28.5 degrees C (oral) and 27.3 degrees C (rectal). The emissions reappeared during rewarming at a mean temperature of 30.1 degrees C (oral) and 30.8 degrees C (rectal). Contralateral auditory stimulation (CAS) led to a decrease of the amplitudes of TEOAE during cooling down to a mean of 33 degrees C/32 degrees C (oral/rectal temperature). During rewarming, influences of the CAS could be recognized, again at an oral temperature above 35 degrees C. The changes to the TEOAE observed in these experiments suggest that hypothermia affects not only the outer hair cells (OHC) of the cochlea but also the efferent supply to the cochlea.

Expression pattern of Drosophila ret suggests a common ancestral origin between the metamorphosis precursors in insect endoderm and the vertebrate enteric neurons

The RET gene, encoding a receptor tyrosine kinase, is unusual among human protooncogenes in that its mutant alleles are implicated in a developmental defect involving enteric neurons as well as in tumorigenesis. The cells affected in both types of disorders are derived from the neural crest. Targeted disruption of mouse ret has revealed an additional role in kidney development. Here we report the analysis of a ret homolog in Drosophila melanogaster, an arthropod with no neural crest. Drosophila ret (D-ret) encodes a protein of 1,235 amino acids that has all of the domains identified in the vertebrate ret, including a cadherin motif. During embryogenesis, D-ret mRNA is first detected in the yolk sac at the late gastrula stage. In the postgastrula, D-ret is expressed in the foregut neurons, excretory system, peripheral ganglia, and the central nervous system. Thus, despite the wide divergence of early embryonic fate maps between vertebrates and invertebrates, D-ret is expressed in cells that are presumed to be the functional equivalents of the ret-expressing cells in vertebrates. Unexpectedly, D-ret is also expressed in the imaginal islands of the endodermal gut. These cells are proliferation-competent precursors for adult midgut that are diffusely embedded in the growth-arrested juvenile gut. These ret-expressing nonneuronal cells are strikingly analogous to vertebrate enteric neurons in their topography, but not in their cell fate. Our finding suggests a previously unrecognized phylogenetic relationship between the ret-expressing cells in vertebrates and the precursor reserves of metamorphosing insects.

Screening for specialized columnar epithelium with methylene blue: chromoendoscopy in patients with Barrett's esophagus and a normal control group

BACKGROUND

Barrett's esophagus is characterized by the presence of specialized columnar epithelium (SCE) in the distal esophagus and is a precursor for dysplasia and adenocarcinoma. Methylene blue is used to selectively stain this type of epithelium within the columnar lined distal esophagus (CLE). The goal of our prospective study was to investigate the staining pattern with methylene blue in patients with visible CLE and a control group with macroscopically normal gastroesophageal junction.

METHODS

Chromoendoscopy of the distal esophagus with 1% methylene blue was performed on a total of 73 patients (51 with visible CLE, 22 normal control subjects). Biopsies were targeted toward stained or macroscopically abnormal mucosal areas. Unstained CLE was sampled by obtaining 4-quadrant biopsy specimens at 2 cm intervals.

RESULTS

The targeted biopsy of stained areas provided histologic proof of SCE with a sensitivity of 98% and a specificity of 61%. The detection of SCE increased with this method in patients with visible CLE (75%), but SCE was also prevalent in the control group (73%). Areas that by their appearance raised a suspicion for dysplasia and adenocarcinoma were already endoscopically apparent in 3 of 4 cases before methylene blue staining and showed different staining patterns.

CONCLUSIONS

Methylene blue staining increases the rate of detection of SCE, both in patients with visible CLE and with normal gastroesophageal junction. For detection of dysplastic or malignant areas it is important to look for visible mucosal changes.

Three-dimensional visualization of coronary arteries in excised hearts

OBJECTIVE

We sought to image coronary arteries in excised hearts.

METHODS

Twelve excised pigs' hearts were imaged in a water bath. The aortic valve was closed surgically. A contrast agent (Echovist) was injected into the aortic root and selectively into single coronary arteries. Three-dimensional (3D) imaging was performed with TomTec Echoscan equipment. Mechanical rotations were performed at 1 degrees intervals. The hearts were visualized by InVivo software. Selective coloring of coronary arteries in 3D data sets was obtained by using color superpositioning, which differentiates information before and after injection of contrast. Distance measurements were performed in conventional 3D echocardiograms of coronary arteries and color-superimposed echocardiograms and compared with those from angiograms and casts.

RESULTS

After a learning curve, during which optimal conditions for the visualization of coronary arteries were determined, a quick display of all major parts of the coronary tree was obtained. Distance measurements (n >400) revealed that fundamental contrast echocardiography overestimated angiography by 25% +/- 5% and casts by 28% +/- 6%. However, distances in color-superimposed echocardiograms (flow mode 4) were not significantly different from those obtained from angiograms and casts. In harmonic contrast echocardiograms, color super-positioning gave smaller distances compared with those from fundamental contrast echocardiograms, though they were still significantly larger than the reference diameters.

CONCLUSIONS

The 3D imaging of epicardial coronary arteries under ideal conditions in a water bath seems feasible and provides insight into coronary visualization with the use of ultrasonography.

Does the application of constraint-induced movement therapy during acute rehabilitation reduce arm impairment after ischemic stroke?

BACKGROUND AND PURPOSE

Motor dysfunction after unilateral deafferentation in primates can be overcome by restraining the unaffected limb. We asked whether a constraint-induced movement (CIM) program could be implemented within 2 weeks after stroke and whether CIM is more effective than traditional upper-extremity (UE) therapies during this period.

METHODS

Twenty-three persons were enrolled in a pilot randomized, controlled trial that compared CIM with traditional therapies. A blinded observer rated the primary end point, the Action Research Arm Test (ARA). Inclusion criteria were the following: ischemic stroke within 14 days, persistent hemiparesis, evidence of preserved cognitive function, and presence of a protective motor response. Differences between the groups were compared by using Student's t tests, ANCOVA, and Mann-Whitney U: tests.

RESULTS

Twenty subjects completed the 14-day treatment. Two adverse outcomes, a recurrent stroke and a death, occurred in the traditional group; 1 CIM subject met rehabilitation goals and was discharged before completing 14 inpatient days. The CIM treatment group had significantly higher scores on total ARA and pinch subscale scores (P:<0.05). Differences in the mean ARA grip, grasp, and gross movement subscale scores did not reach statistical significance. UE activities of daily living performance was not significantly different between groups, and no subject withdrew because of pain or frustration.

CONCLUSIONS

A clinical trial of CIM therapy during acute rehabilitation is feasible. CIM was associated with less arm impairment at the end of treatment. Long-term studies are needed to determine whether CIM early after stroke is superior to traditional therapies.

Enhancing effect of polyoxyethylene alkyl ethers on the skin permeation of ibuprofen

The influence of polyethoxylated non-ionic surfactants on the transport of ibuprofen across rat skin was investigated. The skin permeation of ibuprofen from a series of 17 polyoxyethylene (POE) alkyl ethers containing 5% ibuprofen was determined using Franz diffusion cells fitted with excised rat skins. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were performed for the physicochemical characterization of ibuprofen-surfactant interaction. In vitro transdermal flux through excised rat skin was found in the decreasing order of POE(5)cetyl/oleyl ether (110.24 microg/cm(2)/h)>POE(2)lauryl ether (99.91 microg/cm(2)/h)>POE(2)oleyl ether (67.46 microg/cm(2)/h)>POE(10)stearyl ether (66.19 microg/cm(2)/h). POE(2)oleyl ether showed the longest lag time (2.47 h). The enhancers containing the EO chain length of 2-5, HLB value of 7-9 and an alkyl chain length of C16-C18 were effective promoters of ibuprofen flux. FT-IR and DSC studies to probe the nature of the interaction between the ibuprofen and surfactant indicated that the hydrogen bonding state of ibuprofen was changed from the dimeric form to the carbonyl-hydroxyl (C=O-HO) hydrogen bond form in the presence of excess POE alkyl ether. These results indicated that this new system may be used in developing a transdermal formulation with improved skin permeation of ibuprofen.

Very low platelet counts in post-transfusion purpura falsely diagnosed as heparin-induced thrombocytopenia. Report of four cases and review of literature

Differential diagnosis between post-transfusion purpura (PTP) and heparin-induced thrombocytopenia (HIT) can be difficult in the initial stages of thrombocytopenia, as the early clinical presentations are often similar. Four patients are described who were suspected clinically of suffering from HIT. All four patients had recent blood transfusions and platelet alloantibodies, thus the diagnosis of PTP was made. One lethal gastrointestinal and one retroperitoneal hemorrhage developed in two of the four patients. Unusually, one patient was male and two different platelet alloantibodies were present in his serum; in another patient platelet alloantibodies and HIT-antibodies were detectable. To arrive at the right diagnosis as quickly as possible is vitally important since treatment, which has to be initiated promptly, is very different for the two syndromes. Thus, we suggest that in patients where HIT is suspected, additional information should be sought. If features consistent with PTP (such as a recent blood transfusion or a marked drop in platelet count to below 15 Gpt/L) are present, we recommend parallel testing for platelet alloantibodies to rule out PTP.

Influence of DNA target melting behavior on real-time PCR quantification

BACKGROUND

Quantitative real-time PCR is increasingly used to quantify copy numbers of nucleic acids for clinical applications. We observed that the measurements of allele imbalances of the tumor suppressor gene p16 and the oncogene ErbB-2 yielded results with variable precision under certain experimental conditions.

METHODS

We used the LightCycler(TM) real-time PCR system to quantify different genomic target sequences using hybridization probes or SYBR Green for detection.

RESULTS

With two primer/template systems (p16 and ErbB-2), we observed sinusoidal scattering of the threshold cycle values depending on the capillary position in the thermostated reaction chamber. This scattering depended on the denaturation temperature only when complete genomic DNA was used as template and did not occur when PCR product or restricted or boiled genomic DNA was used or the denaturation temperature in the first cycles was increased (and other targets, such as p53, HBB, IGF-1, GAPDH, and PBGD, did not show this behavior).

CONCLUSIONS

Before a primer system is used for precise quantitative real-time PCR, the dependence of the quantification results on the positions of reaction tubes in the thermocycler should be tested. Our data indicate that amplification efficiencies, especially in the first cycles, depend not only on the priming efficiencies of the primers and the melting temperature of the amplicon, but also on the melting behavior of the amplicon's genomic vicinity. Complete denaturation of genomic DNA is necessary to maximize precision of quantitative PCR. Higher denaturation temperatures in the initial cycles or boiling of DNA before the PCR can improve the accuracy of quantification in some cases.

Indolocarbazoles exhibit strong antiviral activity against human cytomegalovirus and are potent inhibitors of the pUL97 protein kinase

We have analyzed a panel of protein kinase inhibitors (PKIs) and found that some indolocarbazoles (Gö6976, K252a, K252c) proved to be highly effective inhibitors of GCV-sensitive and -resistant human cytomegalovirus (HCMV) strains, but did not show any effect against herpes simplex virus. Antiviral activity was determined by focus reduction assays (IC(50) ranging from 0.009 to 0.4 microM). Other inhibitors of serine/threonine kinases (Gö6850, H-7, roscovitine) were found to be ineffective. Virus yield at 5 days after infection was reduced by three orders of magnitude with nanomolar concentrations of the indolocarbazoles. These compounds were fully effective when added up to 24 h post infection and showed reduced activity up to 72 h post infection. Cytotoxicity assays in proliferating and non-proliferating cells demonstrated that the effective antiviral concentration of these compounds was significantly lower than either antiproliferative (IC(50)/CC(50) ranging from 6.5 to 390) or cytotoxic (IC(50)/CC(50) ranging from 72. 5 to 1000) doses. The effects of PKIs on the virus-encoded protein kinase pUL97 were studied using recombinant vaccinia viruses. Indolocarbazoles strongly inhibited both pUL97 autophosphorylation (IC(50) ranging from 0.0012 to 0.013 microM) and pUL97-dependent ganciclovir phosphorylation (IC(50) ranging from 0.05 to 0.26 microM). Other inhibitors of serine/threonine kinases showed only weak (Gö6850) or no (H-7, roscovitine) effect on these pUL97 functions, while oxoflavone tyrosine kinase inhibitors had no effect at all.

Evolutionary transition pathways for changing peptide ligand specificity and structure

We identified evolutionary pathways for the inter- conversion of three sequentially and structurally unrelated peptides, GATPEDLNQKL, GLYEWGGARI and FDKEWNLIEQN, binding to the same site of the hypervariable region of the anti-p24 (HIV-1) monoclonal antibody CB4-1. Conversion of these peptides into each other could be achieved in nine or 10 single amino acid substitution steps without loss of antibody binding. Such pathways were identified by analyzing all 7 620 480 pathways connecting 2560 different peptides, and testing them for CB4-1 binding. The binding modes of intermediate peptides of selected optimal pathways were characterized using complete sets of substitution analogs, revealing that a number of sequential substitutions accumulated without changing the pattern of key interacting residues. At a distinct step, however, one single amino acid exchange induces a sudden change in the binding mode, indicating a flip in specificity and conformation. Our data represent a model of how different specificities, structures and functions might evolve in protein-protein recognition.

Molecular characterization of the transition state regulator AbrB from Bacillus stearothermophilus

The Bacillus subtilis transition state regulator AbrB(su) is a DNA-binding protein that acts on several genes either as activator, repressor, or preventer. However, among genes under its control, neither common binding sites could be identified nor could the structural features of this broad and specific interaction be elucidated. Attempts to elucidate these interesting features by crystallizing AbrB(su) have failed so far. Therefore, to solve this problem, we focused in this work on identifying an AbrB(su) homologue from Bacillus stearothermophilus. Using a novel method, the entire abrB(st) gene of B. stearothermophilus was cloned and sequenced. The gene encodes a 95 amino acid protein that shows 77% identity and 85% similarity to the mesophilic B. subtilis protein. A calmodulin binding peptide-tagged fusion of the thermophilic gene was constructed for overexpression and efficient affinity column purification of the AbrB(st) protein. The purified protein showed, after removal of the tag, an oligomerization behavior through hexamer formation that is essential for its DNA binding activity.

Frequent loss of heterozygosity at the 19p13.3 locus without LKB1/STK11 mutations in human carcinoma metastases to the brain

Inactivating germline mutations of the novel putative tumor-suppressor gene LKB1/STK11 at 19p13.3 have been shown to cause Peutz-Jeghers syndrome (PJS), an autosomal dominantly inherited disease characterized by a predisposition to mucocutaneous pigmentations, as well as various benign and malignant neoplasms. To elucidate the role of LKB1/STK11 in the carcinogenesis of primary and secondary human brain tumors, a total of 309 tumors were analyzed for loss of heterozygosity (LOH) at microsatellite loci D19S886, DI9S878, and D19S565. Low LOH rates were observed for glioma (17.3%, n = 139), meningioma (5.3%, n = 57), schwannoma (0%, n = 21), pituitary adenoma (18.8%, n = 16), primary CNS lymphoma, neuroblastoma, plasmocytoma, medulloblastoma, germinoma, and papilloma of the choroid plexus (6.6%, n = 15). In contrast, brain metastases exhibited a mean LOH frequency of 42.6% (n = 61), with breast (56.3%) and lung cancer metastases (58.3%) being most frequently affected. Genomic DNA sequencing of the complete coding region of LKB1/STK11 was performed in all brain metastases exhibiting LOH (n = 26); no mutation was revealed, but we did find a germline mutation in a PJS patient. Despite high LOH fiequencies at the 19p13.3 locus in carcinoma metastases to the brain and occasional mutations reported for certain primary carcinomas, there are no mutations in LKB1/STK11. This fact suggests that alterations of LKB1/STK11 occur relatively early in tumorigenesis and are rarely involved in the development of carcinoma metastases. Based on these findings, the genes adjacent to LKB1/STK11 may be relevant for the development of metastases to the brain from certain carcinomas.

Structure of jack bean chitinase

The structure of jack bean chitinase was solved at 1.8 A resolution by molecular replacement. It is an alpha-helical protein with three disulfide bridges. The active site is related in structure to animal and viral lysozymes. However, unlike in lysozyme, the architecture of the active site suggests a single-step cleavage. According to this mechanism, Glu68 is the proton donor and Glu90 assists in the reaction by moving towards the substrate and recruiting a water molecule that acts as the nucleophile. In this model, a water molecule was found in contact with Glu90 O(epsilon1) and Thr119 O(gamma) at a distance of 3.0 and 2.8 A, respectively. The model is in accordance with the observed inversion mechanism.

Glutathione S-transferase genetic polymorphisms and individual sensitivity to the ototoxic effect of cisplatin

One of the side effects of cisplatin therapy in malignant neoplasms is ototoxicity. This effect shows a wide inter-individual range which is more variable than the pharmacokinetic parameters. Oxidative stress has been implicated in cisplatin ototoxicity. The glutathione S-transferase (GST) supergene family encodes isoenzymes that appear to be critical in protection against oxidative stress. Certain GST loci are polymorphic, demonstrating alleles that are null (GSTM1 and GSTT1), encode low-activity variants (GSTP1) or are associated with variable inducibility (GSTM3). The aim of our study was to investigate genetic risk factors involved in the ototoxicity of cisplatin and to determine whether the polymorphisms in five GST genes affect the individual risk of ototoxicity by cisplatin. Two groups of patients were analyzed in this study: group H, 20 patients early and highly sensitive to the ototoxicity of cisplatin; and group N, 19 patients with no hearing impairment under comparable doses of the drug. We found a protective effect for the GSTM3*B allele with a frequency of 0.18 in the group with normal hearing after therapy versus 0.025 in the group with hearing impairment. (chi2=5.37; p=0.02).

Crystal structure of a phage library-derived single-chain Fv fragment complexed with turkey egg-white lysozyme at 2.0 A resolution

The three-dimensional structure of the single-chain Fv fragment 1F9 in complex with turkey egg-white lysozyme (TEL) has been determined to a nominal resolution of 2.0 A by X-ray diffraction. The scFv fragment 1F9 was derived from phage-display libraries in two steps and binds both hen and turkey egg-white lysozyme, although the level of binding affinity is two orders of magnitude greater for the turkey lysozyme. The comparison of the crystal structure with a model of the single-chain Fv fragment 1F9 in complex with hen egg-white lysozyme (HEL) reveals that in the latter a clash between Asp101 in lysozyme and Trp98 of the complementarity determining region H3 of the heavy chain variable domain occurs. This is the only explanation apparent from the crystal structure for the better binding of TEL compared to HEL. The binding site topology on the paratope is not simply a planar surface as is usually found in antibody-protein interfaces, but includes a cleft between the light chain variable domain and heavy chain variable domain large enough to accommodate a loop from the lysozyme. The scFv fragment 1F9 recognizes an epitope on TEL that differs from the three antigenic determinants recognized in other known crystal structures of monoclonal antibodies in complex with lysozyme.

Extracellular matrix effects on a neuroblastoma cell line

Cells of various lines assume similar shapes when grown attached to substrates like coverslips. In contrast, cells cultured in a collagen and/or laminin matrix often assume a relatively normal morphology in comparison with their in situ counterparts. During investigations of neuroblastoma SH-SY5Y cells, an attempt was made to identify culture conditions which would cause the cells to assume a more regular shape. SH-SY5Y cells cultured on bare coverslips, on coverslips coated with rat-tail collagen, and in approximately 1 mm thick gels containing extracellular matrix components were compared. Striking differences were apparent when comparing the gel-cultured cells with cells cultured on coverslips. Cells grown in the gel formed ganglia-like clusters which generated bundles of neurites which targeted other 'ganglia'. The same cells grown on coverslips, whether or not they were collagen-coated, appeared unaware of the presence of other cells, and did not cluster, nor did they generate neurites.

Noninvasive tests as a substitute for histology in the diagnosis of Helicobacter pylori infection

BACKGROUND

Rapid urease tests for Helicobacter pylori have a sensitivity of 80% to 90%. Therefore histologic examination of gastric biopsies is recommended as a "backup" diagnostic test in rapid urease test-negative patients. However, noninvasive tests (urea breath test, serology, whole blood antibody tests) may provide a more rapid diagnosis and be less expensive but offer similar accuracy.

METHODS

Sixty-seven patients (no prior treatment for H pylori, no proton pump inhibitors, antibiotics, or bismuth within 4 weeks) undergoing endoscopy for evaluation of dyspepsia symptoms and testing rapid urease test-negative by antral biopsy were enrolled. All had the following tests: gastric biopsies (2 antral, 1 fundus; H&E and Alcian Yellow stain) examined for gastritis and H pylori; (13)C-UBT; capillary blood for whole blood rapid antibody tests: FlexSure HP, QuickVue, AccuStat, and Stat-Simple Pylori; serum for FlexSure HP; HM-CAP enzyme-linked immunoassay. H pylori infection was diagnosed (reference standard) if chronic gastritis was present on histology and at least 2 of the 3 following tests were positive: urea breath test, H pylori organisms unequivocally demonstrated in biopsies on special stain, and/or enzyme-linked immunoassay. The test and treatment costs per patient were calculated.

RESULTS

Of 67 patients with a negative rapid urease test, 4 were positive for H pylori. None had active peptic ulcer disease. Histology only identified 1 patient with organisms visible on special stain. Using chronic active gastritis (neutrophilic and mononuclear infiltrate) as a diagnostic criterion for H pylori, 6 patients would have been judged positive. However, only 2 of these were truly positive by the reference standard (positive predictive value 33%). Negative predictive value for presence of organisms and chronic active gastritis was 95% and 97%, respectively. All of the noninvasive tests identified all 4 truly positive patients correctly. Urea breath test and FlexSure whole blood assay yielded a substantial number of false-positive results (positive predictive value 31% and 36%, respectively); positive predictive value for the other tests ranged from 50% to 80%. All tests except histology had a negative predictive value of 100%. Histology was the most costly test (p < 0. 001 compared with all other tests), followed by urea breath test and HM-CAP serology (p < 0.001 compared with all rapid antibody tests).

CONCLUSIONS

Whole blood or serum antibody testing is a rapid, accurate, and cost-effective means for establishing H pylori status in rapid urease test-negative patients. Whole blood or serology rapid antibody testing should substitute for histology when the patient has not been previously treated for H pylori.

Screening for thrombophilic risk factors among 25 German patients with cerebral venous thrombosis

OBJECTIVES

In this study the frequency of inherited thrombophilic risk factors in a population of German CVT patients and their influence on clinical outcome were evaluated.

MATERIAL AND METHODS

Twenty-five patients (age 37.1 +/- 16.3 years) with CVT were screened for inherited coagulation disorders. All participants received a full clinical follow-up (mean follow-up period 4.8 +/- 6.4 years).

RESULTS

Inherited thrombophilic risk factors were identified in 9 (36%) of the 25 patients studied. Four were found positive for the heterozygous factor V Leiden mutation, 2 were heterozygous carriers of the prothrombin-G20210A-polymorphism. APC resistance proved to be a reliable screening method for factor V Leiden mutation, whereas genetic evaluation for protein S and C deficiencies failed to demonstrate any mutations despite the identification of 1 patient with a protein C and protein S deficiency each. One patient suffered from a familial plasminogen deficiency. These 9 patients had a less favorable outcome (P < 0.05).

CONCLUSION

Our results demonstrate that screening for inherited thrombophilia should be an integral part in the diagnostic work up of CVT patients. Patients with inherited coagulopathies tended to have a less favorable outcome, corroborating recommendations for a longer period of oral anticoagulation.