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Biomedical subjects

M Wirth

Publications and source records attributed to M Wirth.

At least 91 records · Page 5Linked to original sources
PubMed1993

Dicistronic transcription units for gene expression in mammalian cells.

Dicistronic vectors utilizing the internal ribosomal entry site sequence of poliovirus as the intercistronic region were constructed for gene expression in mammalian cells. We have developed two monocistronic expression vectors which facilitate the creation of dicistronic expression plasmids. The dicistronic expression plasmids encode transcription units which allow the coordinated translation of the two genes. Using internal luciferase and secreted alkaline phosphatase, we show the correlated expression of both reporter genes and expression levels comparable to those achieved by the respective monocistronic expression vectors.

Alkaline Phosphatase↗
PubMed1993

Mycoplasma detection by PCR analysis.

The polymerase chain reaction (PCR) method was used to detect mycoplasma contamination in a panel of 42 continuous cell lines. According to the microbiological cultivation assay on agar, 29 cell lines were chronically infected and 13 cell lines were negative. Sets of outer and inner primers (nested double-step PCR) were applied which anneal to DNA sequences coding for conserved regions of the 16S rRNA. These oligonucleotides allow for the amplification of DNA regions found in at least 25 mycoplasma species (including the ones most commonly found in cell cultures), but do not cross-hybridize with DNA from eukaryotic cells. Mycoplasma-positive cell lines showed distinctive bands in ethidium bromide-stained gels, both after the first round of amplification as well as after the second PCR; all agar-negative cell lines were also unambiguously negative in the PCR assay. Thus, neither false-positive nor false-negative results occurred. Provided that the proper PCR working conditions are scrupulously observed, the PCR amplification has several outstanding advantages: high sensitivity, specificity, reliability, objectivity, speed, and simplicity.

Animals↗
PubMed1993

Treatment of a human renal cell carcinoma in nude mice with recombinant human tumor necrosis factor alpha and etoposide.

The effect of treating a human renal cell adenocarcinoma xenografted into Balb/c-nu/nu (nude) mice with recombinant human tumor necrosis factor alpha (TNF alpha) and the cytostatic agent etoposide (ETP) as monotherapy or combination has been studied. Antitumor effects were evaluated by determining growth of the tumor implants by external caliper measurements and tumor cell proliferation by determining the labelling index (LI) after pulse labelling with 3H-thymidine. The toxicity of the treatment with TNF alpha and/or ETP was also studied by measuring the animal weight. Monotherapy with TNF alpha had no effect on tumor growth or proliferation. Treatment with ETP as a single agent, TNF alpha plus ETP applied concurrently and TNF alpha plus ETP two days later led to a slight inhibition of tumor growth and also to a slight decrease of the LI. In contrast to a monotherapy with TNF alpha, all therapeutic modalities containing ETP showed an increased toxic effect on the animals represented by a distinct weight loss. This suggests that the minute efficacy of the treatment observed could well be due solely to its toxicity. In contrast to two other studies, no additive or synergistic effect of the antineoplastic activity of TNF alpha and/or ETP was found. The intertumoral variation of human renal cell carcinomas could be one reason for the different results with this therapeutic regimen.

Animals↗
PubMed1993

Arthroscopic treatment of full-thickness rotator cuff tears: 2- to 7-year follow-up study.

This study analyzes the midterm follow-up results of 40 full-thickness rotator cuff tears treated by arthroscopic subacromial decompression and debridement. Patients were selected for this prospective study based on a variety of factors, including physiologic age, handedness, activity level in occupation or avocation, and preoperative estimate of repairability. Patients were divided into three groups based on the size of the tear as measured during surgery; results were evaluated on the UCLA shoulder rating scale. This study emphasizes the importance of patient selection when applying arthroscopic treatment for full-thickness rotator cuff tears. Small (0-2 cm) tears (n = 10) in older individuals not involved in strenuous activities did well (90% satisfactory). Patients with larger (2-4 cm) repairable tears (n = 8) did poorly (50% satisfactory) in comparison with our previous study of the results of open repair (84% satisfactory). Arthroscopic treatment in patients with massive, irreparable tears (n = 22) did not restore lost strength or range of motion, but there was significant pain relief, and 86% were satisfied with the results on a limited-goals basis. The study concludes that with proper patient selection, arthroscopic treatment has a valuable, but limited, role in the treatment of full-thickness rotator cuff tears.

Aged↗
PubMed1993

Value of prostate-specific antigen as a tumor marker.

Prostate-specific antigen (PSA) is the most important tumor marker for prostate cancer. However, the diagnostic limits of PSA have to be taken into consideration because PSA is also secreted by normal prostate tissue and, with benign prostatic hyperplasia, false positives are possible. Although there is a direct correlation between the serum PSA concentration and the clinical stage of the tumor, PSA is not sufficiently reliable to determine the stage of the disease on an individual basis. Low serum PSA concentrations (less than 20 ng/ml) in patients with previously untreated prostate cancer seem to be predictive for a negative bone scan. Serum PSA values also reflect the prognosis of the patient. With respect to monitoring patients after definitive therapy, PSA is a very sensitive tumor marker. However, in a small number of patients PSA-negative tumor recurrences occur.

Humans↗
PubMed1993

[Immunotherapy of metastatic renal cell cancer].

In the treatment of advanced renal cell carcinoma, cytokines such as interferons, interleukin-2, tumor necrosis factor and immune therapy with autologous tumor cells and tumor cell vaccines have been tested on a large scale. A definitive cure of a patient with advanced renal cell cancer treated with cytokines or immune therapy has so far not been reported in the literature. The rates of objective remissions (PR and CR) are disappointing and rarely exceed 20% overall. The combination of interferon-alpha and interleukin-2 administered subcutaneously seems to offer the best results with the lowest morbidity. However since standard treatment protocols do not exist, treatment of patients with renal cell carcinoma using these substances should only be performed in prospective trials. Immunotherapy with interferons, interleukin-2, tumor necrosis factor, autologous tumor cells or tumor cell vaccines has to be regarded as experimental.

Carcinoma, Renal Cell↗
PubMed1993

[Synchronous growth of a mixed mesodermal tumor and an adenocarcinoma of the urinary bladder].

The case of synchronous growth of a mesodermal mixed tumour and an adenocarcinoma in the bladder is presented. This is a rare phenomenon. Mesodermal mixed tumours are malignancies with both epithelial (carcinoma) and mesenchymal (sarcoma) differentiation. The term carcinosarcoma is frequently used in the literature. In most cases the prognosis of mesodermal mixed tumours, which depends mainly on the high rate of local recurrences, is poor. Therefore, cystectomy with suprapubic urinary diversion is the treatment of choice. However, results reported in the literature show that transurethral resection of the tumour may be adequate when there is only superficial growth of mesodermal mixed tumours. Short follow-up intervals are absolutely essential for patients treated this way.

Adenocarcinoma, Papillary↗
PubMed1993

[Treatment of ureteral calculi in bone coverage using in situ ESWL in prone position].

From January 1988 to February 1992, a total of 26 patients with calculi in the middle third of the ureter underwent primary in situ ESWL in the prone position. All treatments were performed in sedoanalgesia using the Dornier HM 3 lithotriptor. During and after ESWL in the prone position, severe complications did not occur. Of the 26 patients, 10 (38%) were treated by a single application of ESWL. No auxiliary measures were necessary, and they became stone-free within 3 months following treatment. In another 9 patients (35%) auxiliary measures were required for visualization of radiolucent calculi or to relieve a urinary tract obstruction with incipient septicemia. All these auxiliary measures could be performed in sedoanalgesia. In the remaining 7 patients (27%), in whom stone disintegration following ESWL was incomplete, ureteroscopic lithotripsy techniques had to be applied. One of these 7 patients had to undergo an additional open operative procedure. The results of the present study demonstrate that a majority of patients with calculi in the middle portion of the ureter can become stone-free without invasive lithotripsy techniques following ESWL in the prone position, if necessary plus auxiliary measures, in sedoanalgesia. From these results it can be concluded that primary ESWL in the prone position should be considered for patients with calculi in the middle third of the ureter before invasive lithotripsy techniques are applied.

Adult↗
PubMed1993

[Pneumoscrotum. Case report and review of the literature].

The rare case of a pneumopenis and pneumoscrotum after a thoracic operation is reported. Two subtypes--pneumatocele and subcutaneous emphysema of the scrotum--are differentiated on the basis of anatomy. The cases reported in the literature so far are reviewed. A therapeutic regimen is recommended.

Diagnosis, Differential↗
PubMed1992

M-VAC versus CisCA--chemotherapy in the treatment of advanced bladder cancer.

The results of this study do not demonstrate a superiority of M-VAC chemotherapy over a modified CisCA regimen chemotherapy. M-VAC, however, proved less toxic than CisCA in terms of side effects. Neither CisCA nor M-VAC was effective as a curative treatment for patients with distant metastases. A durable complete remission of 22.5 months was seen in only 2 of the 12 patients with locally advanced tumors without distant metastases treated with M-VAC, and one of 35 months was observed in only 1 of the 6 cases with locally advanced tumors treated with CisCA chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Pharmacokinetic aspects of interferon alfa-2b after intrahepatic or intraperitoneal administration.

The pharmacokinetics of interferon alfa-2b (IFN-alpha-2b) were determined following intraperitoneal (IP) infusion of escalating doses, ie, 5, 10, and 15 million units (MU) and intrahepatal-intraarterial (IA) (IA, bolus v 24 hours continuous infusion of 3 and 5 MU) administration in patients with metastatic cancer. Pharmacokinetic parameters show that bioavailability of IFN-alpha-2b after IP administration is 30 times higher for the peritoneal fluid (PF) than for peripheral blood (PB) explaining also the low incidence of side effects. The high affinity of IFN-alpha-2b to the peritoneal cavity is furthermore substantiated by the total compartment clearance, which is only about 1 1/minute for the PF in comparison to about 30 1/minute as determined for PB. IFN-alpha-2b is eliminated from the PF with a half life (t1/2) of elimination 10 to 32 hours and from the blood with t1/2 of 5 to 13 hours. After IA bolus, IFN is distributed from the blood with a t1/2 below, 2 hours, with dose-dependent serum peak concentrations (c = 47 IU for 3 MU and 145 IU for 5 MU). Twenty-four-hour infusion leads to a steady state within 4 to 6 hours and maximum concentration of 8.5 or 12.5 IU/mL, respectively. During infusion IFN alpha-2b is slowly eliminated with a t1/2 of 16 hours. The lower area under the curve levels after bolus injection may suggest a better tissue uptake of IFN-alpha-2b by the liver. Further studies on pharmacokinetics are warranted to establish exact dose recommendations for an optimal schedule using this route and mode of IFN-alpha-2b administration in mono- and combination therapies.

Female↗
PubMed1991

Instrumental color measurement: a method for judging the appearance of tablets.

An instrumental method for the quantification of the color and the discoloration of tablets is presented. The results are not influenced by external factors and are more rapidly accessible compared with visual determination. Two of the measured parameters, lightness (delta L*) and yellowishness (delta b*) were found to reflect the changes in coloration observed in stability tests on white metoprolol tablets. Correlation studies between visual judgments and instrumental measurements are presented. The instrumental performance was carefully examined, and the results indicate that the employed instrument gives color parameters in the same range for tablet samples irrespective of whether the examined tablet surface has an engraving on it or not.

Color↗
PubMed1991

Different changes of n-6 fatty acids in lipoproteins from hyperlipemic subjects after diets supplemented with n-3 fatty acids.

After diets supplemented with canned mackerel or herring, in a cross-over design, containing different amounts of long-chain n-3 fatty acids (eicosapentaenoic acid, C20:5n-3-EPA, and docosahexaenoic acid, C22(6)n-3-DHA) an increase of both EPA and DHA was confirmed in triglycerides (TG), cholesterol esters (CE) and phospholipids (PL) of very low density (VLDL) and low density lipoproteins (LDL) as well as in high density lipoproteins (HDL) from hyperlipidemic subjects. An unexpected finding was the simultaneous increase of arachidonic acid (C20:4n-6-AA) in TG and CE and its constant portion in PL of lipoproteins, whereas linoleic acid (C18:2n-6-LA) appeared lower in CE and in PL of VLDL + LDL and HDL. In general, the changes were minor after a diet supplemented with canned herring providing a lower dose of n-3 fatty acids. The results indicate dose-related changes not only of n-3 fatty acids, but also of n-6 fatty acids in serum lipids after fish diets. This different behavior of LA and AA in serum lipids might be a new aspect in the interrelations and the dietary modulation of both families of polyunsaturated fatty acids (PUFA). The accumulation of AA in neutral lipids could be linked with an elevation of prostaglandin I2, which was found apart from an increased formation of prostaglandin I3 after diets supplemented with n-3 fatty acids. The concomitant increase of prostaglandins I2 and I3 spotlights widely ignored interrelations within the eicosanoid pathway, which become evident after diets enriched with long-chain n-3 fatty acids.

Adult↗
PubMed1991

Strain-specific and immunodominant surface epitopes of the P2 porin protein of nontypeable Haemophilus influenzae.

The P2 porin protein is the major outer membrane protein of nontypeable Haemophilus influenzae. Five monoclonal antibodies to P2 of four strains of nontypeable H. influenzae were developed by immunizing mice with whole bacterial cells. All five antibodies recognized epitopes on P2 in immunoblot assays of whole organism lysates, purified outer membrane, and purified P2. Competitive enzyme-linked immunosorbent assays and immunoblot assays of cyanogen bromide-digested P2 showed that two antibodies to the P2 protein of strain 1479 recognized different epitopes on the molecule. Immunofluorescence and immunoelectron microscopy demonstrated that each of the five antibodies recognized epitopes that were abundantly expressed on the bacterial surface. Analysis of 120 H. influenzae strains indicated that three of the five antibodies were reactive exclusively with the homologous strain. The remaining two antibodies were reactive with less than 3% of the strains. These studies indicate that the P2 protein expresses a highly strain-specific and immunodominant epitope on the bacterial surface. The expression of strain-specific and immunodominant epitopes on the bacterial surface may represent a mechanism by which the bacterium induces antibodies that will protect against recurrent infection by the homologous strain but will not protect against infection by heterologous strains.

Animals↗
PubMed1991

The current use of interferons, interleukin-2 and tumor necrosis factor in renal cell cancer.

Cytokines such as interferons, interleukin-2 and tumor necrosis factor have been widely tested in the treatment of advanced renal cell cancer. However, the rates of objective remissions (PR and CR) are disappointing and rarely exceed 20% overall. Until now, a definitive cure of a patient with renal cell cancer treated with cytokines has not been reported in the literature. The combination of interferon-alpha and interleukin-2 in low-dose regimens seems to offer the best achievable results with the lowest morbidity of the patients in renal cell cancer. Since optimal treatment regimens are still not defined, treatment with these substances should only be carried out in prospective trials.

Antineoplastic Agents↗
PubMed1991

[The value of interferons, interleukin-2 and tumor necrosis factor in the therapy of renal cell cancer].

The treatment of patients with metastasized renal cell carcinoma by biological response modifiers such as interferon (IFN), interleukin-2 (IL-2) and tumor necrosis factor (TNF) should at present only be carried out in prospective studies since there are still no generally accepted treatment regimens for these substances. In addition, one must remember that only interleukin-2 has been approved for the treatment of renal cell cancer by the Bundesgesundheitsamt (Federal Health Authority) in Berlin. Regarding interferons, IFN-alpha seems to be the most suitable substance for the treatment of renal cell cancer. However, objective response rates (almost exclusively partial responses) can only be expected in about 15% of the cases. By combining IL-2 with lymphokine-activated killer cells or IFN-alpha, objectively assessed remissions can be found in 35%. The approximate complete-response rate using this form of treatment, however, is in the range of 10%.

Carcinoma, Renal Cell↗