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Biomedical subjects

H Pinto

Publications and source records attributed to H Pinto.

At least 19 recordsLinked to original sources
PubMed1999

Stereotactic radiosurgical boost following radiotherapy in primary nasopharyngeal carcinoma: impact on local control.

PURPOSE: Treatment of patients with nasopharyngeal carcinoma using external beam radiation therapy (EBRT) alone results in significant local recurrence. Although intracavitary brachytherapy can be used as a component of management, it may be inadequate if there is extension of disease to the skull base. To improve local control, stereotactic radiosurgery was used to boost the primary tumor site following fractionated radiotherapy in patients with nasopharyngeal carcinoma. METHODS AND MATERIALS: Twenty-three consecutive patients were treated with radiosurgery following radiotherapy for nasopharyngeal carcinoma from 10/92 to 5/98. All patients had biopsy confirmation of disease prior to radiation therapy; Stage III disease (1 patient), Stage IV disease (22 patients). Fifteen patients received cisplatinum-based chemotherapy in addition to radiotherapy. Radiosurgery was delivered using a frame-based LINAC as a boost (range 7 to 15 Gy, median 12 Gy) following fractionated radiation therapy (range 64.8 to 70 Gy, median 66 Gy). RESULTS: All 23 patients (100%) receiving radiosurgery as a boost following fractionated radiation therapy are locally controlled at a mean follow-up of 21 months (range 2 to 64 months). There have been no complications of treatment caused by radiosurgery. However, eight patients (35%) have subsequently developed regional or distant metastases. CONCLUSIONS: Stereotactic radiosurgical boost following fractionated EBRT provides excellent local control in advanced stage nasopharynx cancer and should be considered for all patients with this disease. The treatment is safe and effective and may be combined with cisplatinum-based chemotherapy.

Adolescent↗
PubMed1999

Recruiting minority cancer patients into cancer clinical trials: a pilot project involving the Eastern Cooperative Oncology Group and the National Medical Association.

PURPOSE: Minority accrual onto clinical trials is of significant interest to cooperative oncology study groups. The Eastern Cooperative Oncology Group (ECOG) conducted a study to identify barriers and solutions to African American accrual onto clinical trials. METHODS: We hypothesize that the National Medical Association (NMA) might provide insight into ways to increase minority participation and that ECOG might facilitate that participation. Four sites were selected in which NMA chapters existed and ECOG main institutions with less than half of the corresponding percentage of minorities in their communities entered trials for 1992. Fifteen workshops were conducted using discussions and open-ended, self-administered questionnaires. RESULTS: Seventy percent of NMA physicians cited mistrust of the research centers, fear of losing patients, and a lack of respect from ECOG institutions as the most important barriers to minority cancer patient referrals, compared with 30% for ECOG physicians. Sixty-nine percent of NMA and 43% of ECOG physicians cited a lack of information about specific trials. Nearly half of NMA physicians (47%) cited a lack of minority investigators as a barrier, compared with 4% of ECOG physicians. Solutions by both groups were improved communication (73%) and culturally relevant educational materials (40%). ECOG physicians cited more minority outreach staff as a potential solution (22% v 6%). NMA physicians cited increased involvement of referring physicians (44% v4%). CONCLUSION: NMA physicians who serve a significant sector of the African American population demonstrated a willingness to participate and work with a cooperative group effort to increase participation of minority patients and investigators.

Clinical Trials as Topic↗
PubMed1998

A chitinase encoding gene (chit1 gene) from the entomopathogen Metarhizium anisopliae: isolation and characterization of genomic and full-length cDNA.

There are no reports to date of entire gene sequences coding for chitinolytic enzymes from entomopathogenic fungi, even though these enzymes act synergistically with proteolytic enzymes to solubilize insect cuticle during the key step of host penetration, having considerable importance in the biological control of some insect pests. This paper reports the complete nucleotide sequence and analysis of the chromosomal and full-length cDNA copies of the regulated gene (chit1) coding one of the chitinases produced by the biocontrol agent Metarhizium anisopliae. Degenerated primers, encompassing conserved regions of other fungal chitinases, were used to amplify a 650-bp DNA fragment, which was used to isolate genomic and cDNA clones from M. anisopliae. Albeit at least two different chitinases are characterized in this fungus, only one chit gene was isolated. The chit1 gene is interrupted by three short typical fungal introns and has a 1,521-bp ORF, which encodes a protein of 423 amino acids with a stretch of 35 amino acid residues displaying characteristics of signal peptide. The deduced sequence of the mature protein predicts a 42-kDa protein with pI of 5.8. Southern analysis of genomic DNA indicates a single copy of chit1 in the M. anisopliae genome.

Amino Acid Sequence↗
PubMed1998

Pretreatment and midtreatment measurement of oxygen tension levels in head and neck cancers.

OBJECTIVE: Considerable evidence exists to suggest that tumor hypoxia results in radioresistance. Historically, it has been difficult to assess tumor oxygen tension levels reliably. These levels can now be assessed in head and neck malignancies using the Eppendorf pO2 histograph, which uses a fine-needle electrode and a computerized micromanipulator. This technology was used to compare the pretreatment tumor oxygen tension level in lymph node metastases of patients with head and neck cancer to measurements taken during nonsurgical treatment after a partial response had been achieved. STUDY DESIGN: Prospective study. METHODS: Oxygen tension levels were measured in the cervical lymph nodes of 10 patients with biopsy-proven head and neck squamous cell carcinoma and cervical metastases who were being treated with nonsurgical management. These levels were obtained using the Eppendorf pO2 histograph system. Measurements were taken before the start of treatment and were repeated when the size of the cervical metastatic node had decreased by 50%. Normal subcutaneous tissue was measured during the same session. The mean and median pO2 levels, as well as the percentage of measurements with pO2 less than 5 mm Hg were determined. RESULTS: A mean of 72.6 measurements per session was taken from each lymph node. The median tumor pO2 measurement fell from a mean (+/-SD) of 13.9+/-8.0 mm Hg to 7.3+/-9.9 mm Hg. Even more dramatic, however, was the substantial increase in the percentage of values less than 5 mm Hg, a rise from 29% to 52%. CONCLUSIONS: While there is variability both in the pretreatment oxygenation of head and neck cervical metastases and in the change in tumor oxygen tension during treatment, there appears to be a decrease in the overall oxygenation of the tumors. The dramatic increase in very low oxygen measurements may reflect selective survival of radioresistant or chemoresistant hypoxic tumor cells. Cells at the very low level would be expected to be radiobiologically hypoxic (resistant to radiation-induced cell kill).

Aged↗
PubMed1994

Localization of the Cu/Zn superoxide dismutase gene in the Drosophila willistoni species group by in situ hybridization.

Due to the physiological importance of its product, the Cu/Zn superoxide dismutase enzyme, the gene coding for this enzyme was mapped in five species of the Drosophila willistoni subgroup and in D. nebulosa by in situ hybridization using D. melanogaster as a control. The results indicate that this locus is located on the XR chromosomal arm of the five sibling species and on the XL chromosomal arm of D. nebulosa, suggesting the occurrence of a pericentric inversion before the separation of these entities.

Animals↗
PubMed1981

Evaluation of the gonadotropic responsiveness of the pituitary to acute and prolonged administration of LH/FSH-releasing hormone (lhrh) in untreated patients with congenital adrenal hyperplasia.

The pituitary gonadotropic responsiveness to acute and prolonged administration of LH/FSH-releasing hormone (LHRH) were assessed in 6 patients with untreated congenital virilizing adrenal hyperplasia (partial 21-hydroxylase deficiency). The oldest subjects had normal response in comparison to females at the midfollicular phase, to the acute infusion of 25 ug LHRH regarding both gonadotropins whereas LH secretory area was decreased during the prolonged (100 ug LHRH in 8 hours) infusion with normal FSH secretion. The two youngest subjects, with higher steroid levels in our series, were either unresponsive on both ways of testing or presented pre-pubertal response.

Adolescent↗