Search PubMed⌕ Search

Biomedical subjects

Jonas T Johnson

Publications and source records attributed to Jonas T Johnson.

At least 19 recordsLinked to original sources
PubMed2006

The influence of clinical and demographic risk factors on the establishment of head and neck squamous cell carcinoma cell lines.

The purpose of this study was to generate stable cell cultures from head and neck squamous cell carcinomas (HNSCC), and retrospectively analyze the factors associated with successful cell line establishment. Fifty-two HNSCC cell lines were isolated from a series of 199 tumors collected between 1992 and 1997 at the University of Pittsburgh Medical Center. Cell lines were characterized at the molecular and cellular level to determine the features associated with cell line formation. Successful cell line formation was dependent on multiple factors, including gene amplification involving chromosomal band 11q13, local and/or regional involvement of lymph nodes, and alcohol usage. The establishment of HNSCC cell lines enriches the resources available for cancer research. Our findings indicate that generation of stable cell lines from HNSCC is biased towards tumors with a poor prognosis. Our 52 stable lines comprise one of the largest series of HNSCC cell lines in the literature, with complete demographic, histopathologic, clinical, and survival data.

Adult↗
PubMed2006

Neck dissection: then and now.

The significance of metastatic disease in the lymph nodes of the neck as a critical independent prognostic factor in head and neck cancer has long been appreciated. Although 19th century surgeons attempted to remove involved cervical lymph nodes at the time of resection of the primary cancer, a systematic approach to en bloc removal of cervical lymph node disease, described in detail by Jawdyński in 1888 and popularized and illustrated by Crile in the early 20th century, provided consistent and more effective treatment, and forms the basis of our current techniques. During the first half of the 20th century, developments included preservation of the accessory nerve in selected cases, elective neck dissection performed in association with resection of various primary tumors, bilateral neck dissection and limited neck dissection. The greatest impetus to the status of radical neck dissection came from Martin, whose technique consisted of resection of all lymph nodes from level I-V together with the accessory nerve, internal jugular vein, sternocleidomastoid muscle and various other structures in a single block of resected tissue. Martin's technical precepts were followed until the latter part of the 20th century when modifications in technique began to find general acceptance. The first description of an effective technique of modified radical neck dissection was published in Spanish by Suárez, in 1963. This technique, which preserves important structures, such as the internal jugular vein, sternocleidomastoid muscle and accessory nerve, was refined and popularized by various authors who published their results in the English language literature during the period from 1964 through 1990 and beyond. Modified or "functional" neck dissection avoids much of the morbidity of radical neck dissection while achieving equivalent degrees of control of regional disease in properly selected cases. By the late 20th century, the concept of selective neck dissection, consisting of resection of only the nodal groups at greatest risk for metastasis from a given primary site, was studied and developed. These limited dissections are now widely employed for elective, and in properly selected cases, therapeutic treatment and staging of the neck, and have been proposed for limited cervical recurrences after various chemoradiation protocols. Prospective studies have demonstrated similar rates of neck recurrence and survival after elective selective neck dissection compared to elective modified radical neck dissection. Other modifications and factors applied to treatment of cervical lymph node disease include the use of adjuvant and neo-adjuvant radiation and chemotherapy, a revised system for classification of neck dissections, the identification of various adverse prognostic factors such as extracapsular spread and extranodal soft tissue deposits, application of sentinel lymph node biopsy to staging of the neck, the use of immunohistochemical and molecular techniques for identification of lymph node metastases not detectable by light microscopy, and the possibility of endoscopic neck dissection. The authors conclude that neck dissection, as evolved over the past century, is a fundamental tool in management of patients with head and neck cancer, but is still a work in progress.

Head and Neck Neoplasms↗
PubMed2006

Squamous cell carcinoma of the parotid gland.

BACKGROUND: Our objective was to evaluate the outcome of patients treated for squamous cell carcinoma (SCC) of the parotid gland. METHODS: We conducted a retrospective chart review of the tumor registry from 1982 through 2003 at a tertiary referral medical center. Patients with SCC of the parotid gland were identified and followed for a minimum of 2 years after therapy. RESULTS: SCC involving the parotid was identified in 66 patients. The tumor was a metastasis from a known primary site in 41 patients (62%). In 16 patients (24%), no other primary site was identified, and the tumor may have originated in the parotid gland. Nine patients (14%) were undetermined. Therapy frequently included surgery. The integrity of the facial nerve was preserved in 92% of surgical patients. Only eight patients initially had clinical evidence of cervical metastasis; however, cervical metastasis was identified in 25 patients (44%), changing the course of therapy. CONCLUSION: SCC of the parotid gland was metastatic from a known primary tumor in more than half of the patients. The most common site of the primary tumor was a cutaneous malignancy of the head and neck. The high incidence of cervical lymph node involvement underscores the diagnostic and therapeutic importance of neck dissection with parotidectomy.

Adult↗
PubMed2006

Safety of uvulopalatopharyngoplasty as outpatient surgery.

OBJECTIVE: Determine the admission rate and characterize the complications in uvulopalatopharyngoplasty (UPPP) patients scheduled to have outpatient surgery. STUDY DESIGN AND SETTING: Retrospective review of patients undergoing UPPP between 2000 and 2004 in a tertiary care setting. RESULTS: UPPP alone or in conjunction with tonsillectomy, septoplasty, or supraglottoplasty was carried out in 110 patients. Average preoperative respiratory disturbance index (RDI) was 35. Admission was required in 20 (18%) patients whereas 90 (82%) were discharged on the day of surgery. Admission due to desaturation was noted in 3 (3%) patients. The most common reasons for admission included pain and nausea. There were no major complications. CONCLUSIONS: Careful preoperative selection of patients should permit many patients to undergo UPPP as outpatient surgery. Factors requiring admission may be assessed in the early postoperative period. The rate of respiratory events requiring postoperative admission after UPPP is low. SIGNIFICANCE: UPPP can be carried out safely on an outpatient basis. EBM RATING: C-4.

Adult↗
PubMed2006

Cervical metastasis from squamous cell carcinoma of the maxillary alveolus and hard palate.

OBJECTIVES: Squamous cell carcinoma has a predilection for regional lymphatic metastasis. The occurrence of occult cervical metastases from squamous cell carcinoma of the hard palate and maxillary alveolar ridge has not been studied systematically. We have observed many patients who have returned after resection of a primary cancer in these sites with a delayed cervical metastasis. Some of these patients have died of regional or distant metastasis despite control of their primary cancer. METHODS: We have studied 26 patients with squamous cell carcinoma of the maxillary alveolar ridge and hard palate to define incidence of cervical metastasis. RESULTS: Overall incidence of cervical metastasis was: clinical 2 of 26 (7.6%) and occult 7 of 26 (27%) for a total of 9 of 26 (34.6%). The 5-year disease-specific survival was 13 of 22 (59%). Surgery for regional failure was successful in 66% (6 of 9). Radiation was administered after surgery in eight of nine patients. CONCLUSION: Cervical metastasis from cancer of the palate and alveolar ridge is significant. Regional surgery for recurrent disease usually requires radical or modified radical neck dissection. Selective elective neck dissection should be offered to patients with cancer of the hard palate and alveolar ridge. It affords the patient and the treatment team valuable histologic information, which may help to guide therapy and reduce the potential need for future hospitalization, chemoradiation, and more radical surgery.

Carcinoma, Squamous Cell↗
PubMed2006

Selective neck dissection in patients with upper aerodigestive tract cancer with clinically positive nodal disease.

OBJECTIVES: We evaluated the efficacy of the application of selective neck dissection to cases of clinically node-positive disease. METHODS: We performed a retrospective review at the University of Pittsburgh Head and Neck Cancer Database. A database of 65 patients was followed for an average of 36 months (range, 2 to 128 months) after they underwent selective neck dissection for clinically node-positive regional disease. RESULTS: Regional failure occurred in 8 patients (12.3%). In-field failure was experienced in 4 patients (6.1%), and failures outside the field of dissection occurred in 4 patients (6.1%). The overall incidence of extracapsular spread was 33.8% (22 of 65). Only 2 of 8 regional recurrences were associated with extracapsular spread at the initial neck dissection; however, both recurrences were in the contralateral, undissected side of the neck. Four regional failures were salvaged with surgery, with eventual overall regional control in the neck of 93.9%. Only 1 of 4 ipsilateral recurrences (25%) was successfully salvaged. In contrast, 3 of 4 contralateral failures (75%) were successfully salvaged. In our study population, 21 of 65 cases (32%) that were initially staged as clinically node-positive had no evidence of nodal metastases on pathologic examination. CONCLUSIONS: The application of selective neck dissection and postoperative irradiation in patients with clinically Nl and limited N2 clinical disease appears to be oncologically efficacious. Clinical overstaging occurred frequently in this sample, and may put patients at risk for more morbid surgical procedures.

Follow-Up Studies↗
PubMed2005

Human papillomavirus-16 associated squamous cell carcinoma of the head and neck (SCCHN): a natural disease model provides insights into viral carcinogenesis.

Uncertainty regarding the causality of human papillomaviruses (HPVs) in squamous cell carcinoma of the head and neck (SCCHN) necessitates better in vitro models. We carried out molecular analyses of a novel, naturally HPV-16-transformed SCCHN cell line (UPCI:SCC090) and show high copy number of HPV-16 DNA, present in a head to tail, tandemly repeated integrated state. Sequence analysis of the HPV-16 long control region (LCR) in UPCI:SCC090 revealed a deletion of 163 bp, removing a portion of the enhancer sequence, including the binding sites for the transcription factors YY1 and NF1. The E6 and E7 oncogenes of HPV-16 are expressed at high levels in this cell lines, as determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). UPCI:SCC090 contains wild-type tumour suppressor TP53 gene, and undetectable p53 protein, except after treatment with cisplatin, specific proteasome inhibitors or by E6 RNA interference, suggesting E6-dependent degradation of p53 in this cell line. The results of our studies are consistent with a causative role of HPV-16 in the pathogenesis of SCCHN.

Blotting, Southern↗