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Biomedical subjects

J Beyer

Publications and source records attributed to J Beyer.

At least 181 records · Page 10Linked to original sources
PubMed1996

Kill kinetics of antimicrobial agents against Helicobacter pylori.

We evaluated the activity of clarithromycin, 14-OH clarithromycin, amoxycillin, bismuth, metronidazole and ciprofloxacin against six strains of Helicobacter pylori to determine if there were differences in response to these antimicrobial agents during growth in vitro. Clarithromycin and its 14-hydroxy-metabolite exhibited an early bactericidal activity with at least a 3 log10 reduction after 2-8 incubation. Exposure to bismuth, ciprofloxacin and metronidazole resulted in a > 3 log reduction by 24 h with the greatest decrease in viability occurring between 8 and 24 h. The viable count of three strains was reduced by a 1-2 log10 after 24 h exposure to amoxycillin and by a > 3 log10 after 48 h.

Amoxicillin↗
PubMed1996

Phase II study of paclitaxel in patients with relapsed or cisplatin-refractory testicular cancer.

BACKGROUND: Despite generally high cure rates in patients with metastatic testicular cancer, patients with incomplete responses to cisplatin-based first-line therapy or with relapsed disease have an extremely poor prognosis. Paclitaxel represents an antitumor agent with demonstrated activity in cisplatin-sensitive tumors. In addition, responses to paclitaxel have been observed in patients with platin-refractory ovarian cancers. The current phase II trial evaluates the role of paclitaxel in male patients with cisplatin-refractory or relapsed malignant germ cell tumors. PATIENTS AND METHODS: Twenty-four patients with relapsed, mostly cisplatin-refractory metastatic testicular cancer were treated with paclitaxel as three-hour infusions of 225 mg/m2 at 3-weekly intervals. The patients had received a median of 7 platinum-containing treatment cycles (range 3-12) prior to paclitaxel and 12 patients (50%) had previously received high-dose carboplatin/etoposide-based salvage therapy with autologous stem cell support. RESULTS: Six patients (25%) achieved major responses to paclitaxel with 2 CR (8%) and 4 PR with marker normalisation (17%). In addition, 5 patients (21%) showed disease stabilisation. Median duration of responses to paclitaxel was 8 months (3-16+). Toxicity was tolerable, with mainly granulocytopenia occurring in 50% of patients and peripheral neuropathy > or = grade II in 29%. CONCLUSION: Paclitaxel demonstrates significant antitumor activity in 25% of patients with relapsed or cisplatin-refractory testicular cancer. Combination regimens including paclitaxel may be warranted.

Adolescent↗
PubMed1996

Identification of a 23S rRNA gene mutation in clarithromycin-resistant Helicobacter pylori.

BACKGROUND: Transition mutations (A-G) at residue 2143, cognate to position 2058 in the Escherichia coli 23S rRNA gene, have been shown to confer resistance to macrolides in Helicobacter pylori. This study reports the finding that transversion mutations (A-C) can occur at 2143 as well. MATERIALS AND METHODS: Three clarithromycin-resistant H. pylori isolated from three different patients after treatment with clarithromycin were analyzed for point mutations by cycle sequencing of a 163-bp amplified region surrounding residue 2143 within the conserved loop of the 23S rRNA gene. RESULTS: Nucleotide sequence comparisons of a 163-bp amplified product revealed that A-C transversion mutations occurred at position 2143. H. pylori isolated from the patients prior to treatment were susceptible to clarithromycin and displayed no polymorphism at 2143. CONCLUSION: This is the first report to show that A-C transversion mutations at position 2143 can confer resistance to clarithromycin in H. pylori and further support the role that mutations at position 2143 play in conferring macrolide resistance in H. pylori.

Clarithromycin↗
PubMed1996

Mutations in 23S rRNA are associated with clarithromycin resistance in Helicobacter pylori.

Twelve clarithromycin-resistant Helicobacter pylori isolates (100% of resistant isolates examined) from seven different patients each contained an A-->G transition mutation within a conserved loop of 23S rRNA. A-->G transition mutations at positions cognate with Escherichia coli 23S rRNA positions 2058 and 2059 were identified. Clarithromycin-susceptible H. pylori isolates from 14 different patients displayed no polymorphisms in a conserved loop within domain V of 23S rRNA. The study is the first to report mutations in H. pylori associated with resistance to an antimicrobial agent used in established peptic ulcer treatment regimens.

Anti-Bacterial Agents↗
PubMed1996

High-dose chemotherapy as salvage treatment in germ cell tumors: a multivariate analysis of prognostic variables.

PURPOSE: To identify prognostic variables for response and survival in male patients with relapsed or refractory germ cell tumors treated with high-dose chemotherapy (HDCT) and hematopoietic progenitor cell support. PATIENTS AND METHODS: Three hundred ten patients treated with HDCT at four centers in the United States and Europe were retrospectively evaluated. Univariate and multivariate analysis of patient, disease, and treatment characteristics were used for comparisons of response rates and failure-free survival (FFS). RESULTS: The actuarial FFS rate was 32% at 1, 30% at 2, and 29% at 3 years. Multivariate analysis identified progressive disease before HDCT, mediastinal nonseminomatous primary tumor, refractory or absolute refractory disease to conventional-dose cisplatin, and human chorionic gonadotropin (HCG) levels greater than 1,000 U/L before HDCT as independent adverse prognostic variables for FFS after HDCT. These variables were used to identify patients with good, intermediate, and poor prognoses. In the good-risk category, the predicted FFS rate at 2 years was 51%, compared with 27% and 5% in the intermediate-risk and poor-risk categories (P < .001). The increased risk for treatment failure was due to both a significantly lower rate of favorable responses and a significantly higher rate of relapses. Within the prognostic categories, the particular HDCT regimen or higher dosages of carboplatin or etoposide did not have a significant influence on treatment outcome. CONCLUSION: Prognostic variables for treatment response after HDCT can be identified. The proposed prognostic model might help to optimize the use of HDCT in germ cell tumors and warrants validation in future trials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Impact of preleukapheresis cell counts on collection results and correlation of progenitor-cell dose with engraftment after high-dose chemotherapy in patients with germ cell cancer.

PURPOSE: To identify predictive factors for a good leukapheresis yield and to determine peripheral-blood progenitor cell (PBPC) dose requirements for rapid hematopoietic engraftment. PATIENTS AND METHODS: Seventy-one patients with germ cell cancer (GCC) underwent PBPC harvest for autologous transplantation following high-dose therapy. Aphereses were performed after chemotherapy during granulocyte colony-stimulating factor (G-CSF) administration. RESULTS: A median of two aphereses (range, two to five) resulted in 4.6 x 10(8) mononuclear cells (MNC)/kg, 15.7 x 10(4) colony-stimulating units granulocyte-macrophage (CFU-GM)/kg, and 6.0 x 10(6) CD34+ cells/kg. Peripheral blood MNC count correlated significantly with number of harvested CD34+ cells per kilogram (r = .49; P < .0001) and with CFU-GM count per kilogram (r = .35; P < .002). Circulating CD34+ cells from peripheral blood gave the best correlations to collected CD34+ cells per kilogram (r = .92; P < .0001), as well as to harvested CFU-GM per kilogram (r = .48; P < .0001). A preleukapheresis number of CD34+ cells greater than 4 x 10(4)/mL was highly predictive for a PBPC collection yield that contained more than 2.5 x 10(6) CD34+ cells/kg harvested by a single leukapheresis. After autologous transplantation, 41 patients were assessable for hematopoietic engraftment. They engrafted in a median time of 9 days (range, 7 to 18) to a WBC count greater than 1.0 x 10(9)/L, 10 days (range, 7 to 18) to an absolute neutrophil count (ANC) greater than 0.5 x 10(9)/L, and 11 days (range, 7 to 62) to a platelet (PLT) count greater than 20 x 10(9)/L. Good correlations were seen between reinfused CD34+ cell count and recovery of WBC count, ANC, and PLT count, with r values of .65 (P < .001), .65 (P < .001), and .45 (P < .03), respectively. Patients reinfused with a PBPC dose greater than 2.5 x 10(6) CD34+ cells/kg recovered hematopoiesis in a significantly shorter time than patients who received less than 2.5 x 10(6) CD34+ cells/kg. CONCLUSION: Rapid hematopoietic engraftment can be achieved by a PBPC dose of greater than 2.5 x 10(6) CD34+ cells/kg. When circulating preleukapheresis CD34+ cell counts are greater than 4 x 10(4)/mL, a PBPC autograft that contains more than 2.5 x 10(6) CD34+ cells/kg can be collected by a single leukapheresis.

Adult↗
PubMed1996

[Is preoperative site diagnosis in organic hyperinsulinism from the viewpoint of the surgeon still necessary today? Results of a consecutive series and analysis of the literature].

To answer the open question whether a preoperative localization diagnostic is necessary in organic hyperinsulinism we prospectively investigated our 28 patients with an organic hyperinsulinism who were operated on between September 1, 1985 and December 31, 1994. Additionally we performed an analysis of the literature. In case of a solitary adenoma the preoperative localization diagnostic had a sensitivity between 28.4% (sonography) and 84% (endosonography). The combination of all preoperative localization procedures had a sensitivity between 70% (literature) and 90% (own patient material). With palpation and intraoperative sonography 97.1% (own patient material 100%) of all solitary adenomas could be found during first exploration. Multiple adenomas and reoperations have special problems. The pre- and intraoperative localization diagnostic failed in every fourth patient. In conclusion, in case of a primary operation without a MEN syndrome a preoperative localization procedure is not necessary due to the high sensitivity of the intraoperative diagnostic. In case of a MEN syndrome or reoperation a preoperative localization diagnostic is still advisable although the sensitivity is low.

Adenoma, Islet Cell↗
PubMed1995

Prevalence of myxomatous mitral valve prolapse in patients with lymphocytic thyroiditis.

In conclusion, given the cardiac (mitral regurgitation, endocarditis, thromboembolic complications, arrhythmic sudden death) and neurologic (cerebral embolic event) complications of the pathologic forms of MVP, physicians should look carefully for myxomatous involvement of the mitral valve and prolapse in patients with autoimmune thyroid diseases. Patients should be monitored and prophylactic antibiotic treatment recommended when appropriate.

Adult↗
PubMed1995

[Diagnosis of the origin and therapy of organic hyperinsulinism].

BACKGROUND: The need for preoperative localization of an insulinoma is still under discussion. The aim of the present study was to determine the usefulness of preoperative localization of the tumour, to investigate the operative risk and to analyse the long-term course. PATIENTS AND METHODS: The sensitivity of the diagnostic workup was investigated prospectively in 26 patients operated on between 1. 9. 1985 and 31. 8. 1994 for hyperinsulinism at the surgical department of the university hospital in Mainz. RESULTS: In the case of solitary adenomas the sensitivity of preoperative sonography was 43%, that of CT 57%, and that of angiography 85%. Intraoperatively, all solitary adenomas were palpable and were to be seen at sonography. In a patient with multiple adenomas, only one tumour was seen sonographically. The postoperative course was unremarkable in 18 out of 27 operations on the pancreas; two patients died later. After a mean follow-up of 51 months, all patients were free of hypoglycaemic attacks. CONCLUSIONS: The results show that localization of the tumour prior to the first operation is no longer necessary in patients with no MEN syndrome. In the presence of the latter, however, it is recommended despite its low sensitivity. Although a permanent cure is possible with surgery, the morbidity of the operation is not negligible.

Adult↗
PubMed1995

Autografting with blood progenitor cells: predictive value of preapheresis blood cell counts on progenitor cell harvest and correlation of the reinfused cell dose with hematopoietic reconstitution.

One hundred and nine patients suffering from various malignancies underwent 285 apheresis procedures for PBPC collection. A median of two leukaphereses (range: 2-5) resulted in median numbers of 4.6 x 10(8) MNC/kg, 14.1 x 10(4) CFU-GM/kg, and 6.0 x 10(6) CD34+ cells/kg. Preleukapheresis peripheral blood CD34+ cells correlated significantly with collected CD34+ cells/kg (r = 0.94; p < 0.0001) and with CFU-GM/kg (r = 0.52; p < 0.0001). A value > 4 x 10(4) CD34+ cells/ml was highly predictive for a collection yield > 2.5 x 10(6) CD34+ cells/kg harvested by a single leukapheresis. Sixty patients were evaluated for hematologic reconstitution and engrafted in a median time of 10 days for WBC > 1.0 x 10(9)/l (range: 7-21 days), 10 days for ANC > 0.5 x 10(9)/l (7-20) and 11 days for PLT > 20 x 10(9)/l (7-62). Reinfused CD34+ cells/kg correlated significantly with hematologic engraftment (r = 0.44-0.52 and p < 0.006-0.001) as well as CFU-GM/kg (r = 0.36-0.44 and p < 0.007-0.001). A progenitor cell dose > 2.5 x 10(6) CD34+ cells/kg or > 8.0 x 10(4) CFU-GM/kg led to a significantly faster recovery for WBC, ANC, and PLT when compared with patients receiving < 2.5 x 10(6) CD34+ cells/kg or < 8.0 x 10(4) CFU-GM/kg. We conclude that rapid hematopoietic engraftment after high-dose therapy and PBPC reinfusion correlates well with a progenitor cell dose > 2.5 x 10(6) CD34+ cells/kg or > 8.0 x 10(4) CFU-GM/kg, and that above a preleukapheresis threshold of 4 x 10(4) CD34+ cells/ml a PBPC autograft containing > 2.5 x 10(6) CD34+ cells/kg can be collected by a single leukapheresis. We suggest that patients recovering from myelosuppression should be monitored for CD34+ cells in serial blood samples to determine the course of circulating hematopoietic progenitor cells. This issue will help to define the optimal time point to start apheresis and to predict a PBPC autograft harvested by a single leukapheresis, which will lead to rapid and stable hematopoietic reconstitution following transplantation.

Adolescent↗
PubMed1995

Transport and storage of Helicobacter pylori from gastric mucosal biopsies and clinical isolates.

Various transport and storage conditions for the recovery of Helicobacter pylori from gastric biopsies were evaluated. Gastric mucosal biopsies from 16 Helicobacter pylori-infected patients were stored in cysteine-Albimi medium containing 20% glycerol in a refrigerator (4 degrees C) for 1 and 2 weeks and in a -20 degrees C laboratory freezer for 4 and 12 weeks. Two clinical isolates were stored in saline, Stuart's transport media, cysteine-Albimi broth with 20% glycerol, brucella broth with 20% glycerol and skim milk with 17% glycerol at room temperature, 4 degrees C, -20 degrees C and -70 degrees C. Storage at 4 degrees C for 1 and 2 weeks resulted in Helicobacter pylori recovery from 81% and 19% of biopsies, respectively. Storage at -20 degrees C yielded Helicobacter pylori recovery in 100% and 57% after 4 and 12 weeks, respectively. At room temperature after 6 h, the Helicobacter pylori titer was reduced. The best storage media for frozen isolates were skim milk/glycerol, brucella broth/glycerol and cysteine-Albimi/glycerol (in descending order). Recovery was better at -70 degrees C than -20 degrees C.

Biopsy↗
PubMed1995

In-vivo investigation of material quality of bone tissue by measuring apparent phalangeal ultrasound transmission velocity.

The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influence the result. In humans APU was measured in the mediolateral direction at the midphalanx of the middle finger. In 53 healthy subjects (15-81 years old; 27 women, 26 men), there was a decrease of APU with age (r = -0.30, p < 0.05). Further, when comparing the results of both hands intraindividually almost identical values indicated constant intraindividual architecture of bone at this location. There was no evidence for a relation of APU to physical load comparing dominant and nondominant hand and relating the results to subjectively estimated physical load. In a second group of 43 perimenopausal women (47-60 years old), APU, which again decreased with age (r = -0.33, p < 0.05), was found not to be correlated to BMD measured by SPA at the distal forearm (cortical bone).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗