Biomedical subjects

J A Guerra

Publications and source records attributed to J A Guerra.

6 recordsLinked to original sources

PubMed2000

Search for antiviral activity in higher plant extracts.

In the course of our search for plant natural products as antiviral agents, extracts of ten plants from the Iberian Peninsula were tested for antiviral activity against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV) and poliovirus type 1. Aqueous extracts of five of these medicinal plants, namely Nepeta nepetella (150-500 microg/mL), Nepeta coerulea (150-500 microg/mL), Nepeta tuberosa (150-500 microg/mL), Dittrichia viscosa (50-125 microg/mL) and Sanguisorba minor magnolii (50-125 microg/mL), showed a clear antiviral activity against two different DNA and RNA viruses, i.e. HSV-1 and VSV. Only the medicinal plant Dittrichia viscosa was active against an additional virus, poliovirus type 1.

Antiviral Agents↗

PubMed1998

A phase II study of a novel gemcitabine plus cisplatin regimen administered every three weeks for advanced non-small-cell lung cancer.

BACKGROUND: The aim of this study was to determine the clinical activity and toxicity of a novel chemotherapy combination regimen of gemcitabine plus cisplatin, administered every three weeks, in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Twenty-six previously untreated stages III (14) and IV (12) patients were included. Gemcitabine was administered on days 1 and 8 at a dose of 1250 mg/m2 and cisplatin was administered at a dose of 100 mg/m2 on day 1, every 21 days. RESULTS: Twenty-five patients were evaluable for response. One patient achieved a complete response, and 16 patients partial responses. The overall response rate was 65.3% (95% CI: 45%-82%). The main toxicity was hematological: neutropenia NCIC-CTC grade 3-4 in 54% of the patients, and thrombocytopenia grade 3-4 in 23%. The non-hematological toxicity was mild and tolerable. Only 13% of gemcitabine injections were dose-reduced or omitted due to toxicity. The actual dose-intensity of gemcitabine was 715 mg/m2/week, and 31 mg/m2/week for cisplatin. These figures represent the 86% and 93% of the theoretical dose intensity of both drugs, respectively. With a median follow-up of 10 months (range 7-13), 17 patients are still alive and nine have died. The median overall survival is 12 months. CONCLUSION: This novel combination of gemcitabine and cisplatin administered every three weeks is well tolerated and induces a remarkably high response rate. The regimen proves more interesting than the four-week schedules, particularly regarding patients who are candidates for local therapy.

Adult↗

PubMed1997

Patient selection in high-dose chemotherapy trials: relevance in high-risk breast cancer.

PURPOSE: To evaluate the impact of the selection criteria that are used in current high-dose consolidation chemotherapy (HDCT) trials on the outcome of high-risk breast cancer patients treated with conventional adjuvant chemotherapy. PATIENTS AND METHODS: From 1975 to 1995, 265 breast cancer patients at our institution showed involvement of ten or more positive axillary lymph nodes. Of these, 171 received standard adjuvant combination chemotherapy, but not HDCT consolidation, and were the subjects of our study. One hundred twenty-eight patients met the standard selection criteria for HDCT with hematological support (< 60 years, no significant concomitant disease, and no progression during adjuvant treatment), whereas 43 did not. Clinical outcome was analyzed by using disease-free survival (DFS) and overall survival (OS) as endpoints. To provide an assessment of the short-term efficacy of HDCT, we also evaluated the outcome in a cohort of 39 patients from the last 4 years who met the criteria for, and were actually treated with, HDCT after adjuvant chemotherapy. RESULTS: With a median follow-up of 4.4 years (range, 0.7 to 17.2 years), 112 of the 171 patients have had a relapse, and 87 have died. The estimated 5-year DFS was 32.3%, and OS was 49.4%. DFS was significantly higher for patients who met the HDCT criteria (36.6% at 5 years) than for those who did not (15.8% at 5 years; P < .05). OS was also significantly more favorable in patients meeting HDCT criteria (55.4% at 5 years) than in patients not meeting HDCT criteria (22.7% at 5 years; P < .01). We performed a multivariate analysis to adjust for other potential prognostic factors and found that meeting the HDCT criteria and having undergone locoregional radiotherapy were the only significant independent predictors for DFS and OS. Finally, we compared the outcome of the 128 patients who met the HDCT criteria and were treated with conventional adjuvant chemotherapy only with that of the 39 patients who met the criteria and who actually underwent HDCT, and we did not observe significant differences in the DFS or OS between these groups. CONCLUSIONS: Meeting HDCT inclusion criteria is an independent indicator of favorable prognosis in high-risk breast cancer patients. The selection of patients by these criteria may explain, at least in part, the promising short-term results of nonrandomized adjuvant HDCT trials in high-risk breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1994

Influence of a base on coronal microleakage of post-prepared teeth.

This study compared the coronal microleakage of post-prepared teeth with and without the placement of a zinc oxide-eugenol cement seal coronal to the gutta-percha. Forty single-rooted extracted teeth were prepared and obturated with sealer and gutta-percha. These teeth were divided into two groups of teeth 20 each. A post space was prepared for each tooth so that 5 to 6 mm of gutta-percha remained in one group and 3 to 4 mm in the other group. To the latter group, 2 to 3 mm of zinc oxide-eugenol cement base was placed directly coronal to the gutta-percha. The sealer was allowed to set for 48 h and the outer root surfaces of the teeth were covered with finger nail varnish and sticky wax, except for the access openings. The teeth were immersed in dye for 1 wk to allow coronal microleakage. The specimens were sectioned and measurements were made on the extent of dye penetration into the root filling. The teeth without a zinc oxide-eugenol base showed significantly greater microleakage than those protected with a zinc oxide-eugenol base.

Dental Cavity Lining↗

PubMed1993

Electric pulp tester and apex locator barrier technique.

Use of the electric pulp tester and the apex locator during assessments of pulp vitality and root length determination involves bacterial cross-contamination of the metal surfaces of the probe tip and lip clip inserts which contact the oral hard and soft tissues. Reuse of these endodontic aids necessitates the sterilization or disinfection of the metal insert or the acquisition of extra attachments. A barrier technique that protects the electric pulp tester probe tip and the apex locator lip clip from bacterial contamination and employs the principle of electric conductive bridging is presented.

Dental Pulp Test↗

PubMed1992

Root end isolation for retrograde fillings.

Isolation and moisture control of the root end of a tooth with a large periapical lesion is normally accomplished with the aid of bone wax, cotton pellets, or sterile gauze saturated with a suitable hemostatic agent. An alternative procedure, a simple and effective rubber dam technique, is presented demonstrating isolation of an apex before reverse filling.

Adult↗