Search PubMed⌕ Search

Biomedical subjects

J T Johnson

Publications and source records attributed to J T Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Progressive septal and palatal perforation secondary to intranasal cocaine abuse.

Septal perforation from intranasal cocaine abuse is well recognised. We present a case of progressive septal as well as palatal perforation. Progression from septal perforation to palatal perforation occurred after cessation of intranasal cocaine abuse. This patient had a weakly positive cytoplasmic antineutrophilic cytoplasmic antibody (C-ANCA) but no histologic evidence of Wegener's Granulomatosis. The differential diagnosis for septal and palatal perforation is reviewed. This case represents the fifth reported case of palatal perforation secondary to cocaine abuse in the literature, and the second associated with positive C-ANCA.

Administration, Intranasal↗
PubMed1998

A new technique for laparoscopic splenectomy with massively enlarged spleens.

Splenectomy is indicated in several hematological disorders and it can be particularly challenging in children with sickle cell disease, splenomegaly, and recurrent sequestration. Over the last 6 months, we have developed a new technique for laparoscopic splenectomy (LS) for hypersplenism and splenomegaly in five children with sickle cell disease. The average age of our patients was 6 years (range, 2-11), and the average weight was 18.7 kg (range, 13.2-30.1). On preoperative ultrasound, spleen size index ranged from 0.42 to 0.76. For the LS, four trochars were placed. One patient, who also underwent a laparoscopic cholecystectomy, had six trochars placed, two of which were used for both cholecystectomy and splenectomy. After laparoscopic mobilization of the spleen and hilar vascular stapling, a Steiner electromechanical morcellator was inserted through the 12-mm port to extract cores of splenic tissue until complete splenectomy was achieved. No patient required conversion to an open procedure or creation of a larger incision to remove the massively enlarged spleen. Operative time averaged 190 minutes; the combined LS and cholecystectomy took 245 minutes. Postoperative length of stay was <2 days for all patients. There were no complications, and no patient required postoperative transfusion. Based on these early findings, we conclude that intracorporeal coring of splenic tissue allows for safe and complete laparoscopic removal of very large spleens in small children. It provides expedient recovery and minimal postoperative pain and scarring. This new technique should enable surgeons to perform LS even in patients with massive splenomegaly, eliminating the need for large and cumbersome intracorporeal bags or the creation of additional incisions to remove the spleen.

Child↗
PubMed1997

Effectiveness of selective neck dissection for management of the clinically negative neck.

OBJECTIVE: To determine the effectiveness of selective neck dissection for management of the clinically negative neck in head and neck squamous cell carcinoma. DESIGN: A retrospective comparison of patients treated electively with selective neck dissection and comprehensive neck dissection. SETTING: Academic tertiary referral center. PATIENTS: Patients with clinically negative necks and previously untreated head and neck squamous cell carcinoma. INTERVENTION: Elective neck dissection, surgical treatment of the primary lesion, and postoperative radiotherapy as indicated. OUTCOME MEASURES: Regional recurrence, distant metastasis, and disease-free survival. RESULTS: Selective neck dissection was as effective as comprehensive procedures for staging the clinically negative neck. Occult metastases had a statistically significant effect on patient outcome as measured by distant metastasis. CONCLUSION: Elective neck dissection provides invaluable staging information, which guides the decision for adjuvant therapy.

Adult↗
PubMed1997

Lack of serologic evidence for Helicobacter pylori infection in head and neck cancer.

BACKGROUND: Several epidemiologic investigations have established a link between Helicobacter pylori infection and gastric malignancies. Because the stomach is in continuity with the oral cavity and the bacterium has been isolated from dental plaque and saliva, we hypothesized that H. pylori infection of the upper aerodigestive tract might result in mucosal disruption, allowing for subsequent transformation by known carcinogens such as tobacco and alcohol. METHODS: To test this hypothesis, we assayed for the presence of IgG antibodies to H. pylori in the serum of 21 patients with squamous cell carcinoma of the head and neck (SCCHN) and 21 matched controls without a history of head and neck cancer. RESULTS: The incidence of seropositivity in the SCCHN patients was 57% and in the controls, 62% (p > 0.05). CONCLUSIONS: These data do not support an etiologic role for H. pylori infection in head and neck cancer.

Antibodies, Bacterial↗
PubMed1997

Comparison of ampicillin/sulbactam versus clindamycin in the prevention of infection in patients undergoing head and neck surgery.

BACKGROUND: Patients requiring major oncologic head and neck surgery are at high risk for postoperative wound infection when the surgical site is contaminated by secretions from the upper aerodigestive tract. Studies to identify agents active in the prevention of postoperative wound infection may serve to reduce patient morbidity. METHODS: Patients scheduled for a major contaminated head and neck surgical procedure were randomly assigned to receive either ampicillin/sulbactam or clindamycin. Medication was administered 1 to 2 hours prior to surgery and every 6 hours, for a total of five doses. Postoperatively, patients were followed daily for the development of wound infection or other septic complication. RESULTS: A total of 242 patients were enrolled in the study; 119 received ampicillin/sulbactam, and 123 received clindamycin. A total of 169 patients were considered evaluable. Of the evaluable patients, 14% in each group developed a postoperative wound infection. There were no statistically significant differences between the number of days to onset of wound infection, nor was there a statistically significant difference in the rate of non-wound infections in the two groups. There were no statistically significant differences between the intent to treat group and the evaluable group of patients. CONCLUSION: It is concluded that ampicillin/sulbactam is as safe and effective as clindamycin in preventing postoperative wound infection following major head and neck surgery.

Adolescent↗
PubMed1997

Development of distant metastasis after treatment of advanced-stage head and neck cancer.

BACKGROUND: The recognition of risk factors for the development of distant metastasis is necessary for identifying high-risk patients who may benefit from systemic therapy. Previous investigations studying possible risk factors have been heterogeneous, with patients having varied forms of therapy. This study is designed to evaluate the clinical and histologic risk factors for the development of distant metastasis (DM) in patients with only advanced-stage head and neck squamous cell carcinoma after surgery and radiotherapy. METHODS: Retrospective analysis of a cohort of potentials with-surgically treated stage III and IV squamous cell carcinoma of the hypopharynx, tongue, and supraglottic larynx between 1988-1992. The cohort consisted of 130 patients of which 30 patients developed DM as the initial site of failure. All patients underwent surgical resection of the primary. Neck dissection was performed in 26 of 30 (87%0 patients who developed distant metastasis. Almost all patients received radiation therapy. Patients who initially developed DM (DM group) were compared with patients who did not initially develop DM (no DM group) with respect to certain clinical and histo-pathological factors. RESULTS: The majority of patients in the DM group had advanced T stage and clinically palpable cervical lymph nodes (73% and 93% respectively). In the no DM group, most patients had advanced T stage (85%) but 42% of the patients had stage NO necks (p < .05). Eighty-eight percent of patients in the DM group and 60% of patients in the no DM group had histological evidence of extracapsular spread of tumor from cervical lymph nodes (p < .05). Three or more positive lymph nodes were found in 69% of patients who developed DM and in only 35% of patients in the no DM group (p < .05). Age, gender, primary site, history of radiation therapy, perineural invasion and tumor grade were not associated with a higher risk for DM (p > .05). CONCLUSION: Patients wit clinically palpable neck disease (N1-3), histological evidence of metastatic nodal disease, extracapsular spread, and three or more positive lymph nodes are at greater risk of developing failure at distant sites. This subset of patients should have an extensive evaluation for distant metastatic disease and should be considered for systemic therapy.

Adult↗
PubMed1997

Salivary gland lymphoid infiltrates associated with lymphoepithelial lesions: a clinicopathologic, immunophenotypic, and genotypic study.

The criteria for distinguishing benign lymphoepithelial lesions (BLEL) from low grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type in salivary glands and the significance of genotypically documented clonality in this setting are controversial. In addition, the clinical implications of a neoplastic diagnosis are unclear. The histopathologic features of 68 specimens from 49 patients with at least one salivary gland biopsy with LEL together with available clinical data were, therefore, reviewed. Paraffin section immunohistochemical (IHC) stains for kappa, lambda, CD3, CD20, and CD43; in situ hybridization (ISH) for kappa and lambda; and polymerase chain reaction (PCR) for immunoglobulin (Ig) HC rearrangement were performed. The 61 salivary gland specimens were classified as BLEL-13, BLEL with monocytoid B-cell (MBC) halos (BLEL-halo-8), low grade B-cell lymphoma of MALT type with confluent zones of MBC or other atypical lymphocytes (ML-MALT-24), low grade B-cell lymphoma of MALT type with monoclonal plasma cells (ML-MALT-PC-12), and high grade B-cell lymphoma of MALT type (MALT-high grade-4). Soft tissue and perineural invasion was not observed in BLEL and was most common in the MALT lymphomas. Lymph node involvement was identified in six patients at the time of their salivary gland MALT lymphomas but in none with BLEL. CD43+ B cells were seen most commonly in ML-MALT but were present in all other categories except MALT-high grade. Clonal B cells were identified by PCR in 5 of 12 BLEL, 5 of 8 BLEL-halo, 17 of 22 ML-MALT, 6 of 10 ML-MALT-PC, and 3 of 3 MALT-high grade biopsies. All ML-MALT-PC were clonal by ISH or IHC. Repeat biopsies in 14 patients most commonly showed a BLEL/ML-MALT lesion in an ipsilateral or contralateral salivary gland with one transformation to a MALT-high grade. Although only a few patients are known to have received chemoradiation or radiation therapy, most patients with low-grade lesions have pursued an indolent course. These data show the presence of two types of borderline lesions within the spectrum of lymphoid proliferations associated with salivary gland LEL. One has clonal B cells without histological features of neoplasia and the other nonconfluent MBC extending beyond the confines of LEL ("halos"). They share some features with the infrequent nonneoplastic BLEL and others with the more common low-grade B-cell lymphomas of MALT. A few high-grade B-cell lymphomas of MALT were also identified including a rare example of transformation from a low- to high-grade lesion. The optimal therapeutic approach for the borderline and low-grade lesions and the reason why so many of the lymphoproliferative lesions associated with LEL remain localized to the neck remain to be defined.

Adult↗
PubMed1997

Reaction time and assessments of cognitive effort as predictors of eyewitness memory accuracy and confidence.

The authors investigate reaction time, subjective assessments of memory processing, and confidence as predictors of memory for the details of a crime. The authors also examine the mediation of a previously identified difference between recognition tasks and recall tasks in the correlation between confidence and accuracy. College undergraduates (n = 111) answered either recognition or recall questions. Reaction time and subjective assessments of cognitive effort were both negatively related to confidence and accuracy. Subjective assessments, however, were superior predictors of confidence, whereas reaction time was a unique predictor of accuracy. The reaction time-confidence and reaction time-accuracy correlations were stronger under recall conditions than under recognition conditions. Multiple regression results suggested a possible explanation for the superior insight of recall participants into memory accuracy.

Adult↗
PubMed1997

QT interval changes following neck dissection. A stratified prospective study.

Studies from Europe have suggested that neck dissection, especially right radical neck dissection, causes a dangerous prolongation of the QT interval. Sudden cardiac arrest due to QT prolongation has been reported following right radical neck dissection. We investigated the prevalence of QT interval prolongation following neck dissection. Electrocardiogram tracings from 45 patients who underwent different combinations of neck dissection were studied. Preoperative and postoperative tracings were interpreted by a cardiologist blinded to the patient identification of each tracing. There were 28 unilateral neck dissection patients and 17 bilateral neck dissection patients eligible for analysis. There were 7 patients in the classic right radical neck dissection group, and only 3 of these had no neck dissection on the left. Comparisons of preoperative versus postoperative corrected QT interval for all subjects did not indicate a significant change. Stratification by neck dissection type (radical, modified or selective, and carotid artery resection) or by side dissected (left, right, or both) also showed no significant differences. No malignant arrhythmias were encountered. Thus, in contrast to the European experience, our findings show no significant predictable change in the QT interval after any of the combinations of neck dissection. Head and neck surgeons should be aware of the possibility of postoperative QT interval prolongation following neck dissection, although in the absence of other risk factors it appears to be a rare occurrence.

Analysis of Variance↗
PubMed1997

Impact of rater knowledge on sexually abused and nonabused girls' scores on the Draw-A-Person: Screening Procedure for Emotional Disturbance (DAP:SPED).

Human figure drawings collected from a clinical sample of 20 sexually abused and 20 nonsexually abused girls were randomly assigned to 1 of 2 case descriptions: Actual, in which raters were told the girls' actual abuse status, or Pretend, in which raters were told that drawings were made by girls with the opposite abuse status. Using the Draw-A-Person: Screening Procedure for Emotional Disturbance (DAP:SPED) scoring system developed by Naglieri, McNeish, and Bardos (1991), three raters independently scored 44 randomly ordered protocols, 4 of which were commonly rated as checks for rater accuracy and observer drift. Results revealed no significant effect for girls' abuse status or the case description given to raters, thereby suggesting that the DAP:SPED is sufficiently objective to withstand the confounding influence of varying case descriptions.

Adolescent↗
PubMed1997

Fine mapping of an imprinted gene for familial nonchromaffin paragangliomas, on chromosome 11q23.

Hereditary nonchromaffin paragangliomas (PGL; glomus tumors; MIM 168000) are mostly benign, slow-growing tumors of the head and neck region, inherited from carrier fathers in an autosomal dominant fashion subject to genomic imprinting. Genetic linkage analysis in two large, unrelated Dutch families assigned PGL loci to two regions of chromosome 11, at 11q23 (PGL1) and 11q13.1 (PGL2). We ascertained a total of 11 North American PGL families and confirmed maternal imprinting (inactivation). In three of six families, linkage analysis provided evidence of linkage to the PGL1 locus at 11q23. Recombinants narrowed the critical region to an approximately 4.5-Mb interval flanked by markers D11S1647 and D11S622. Partial allelic loss of strictly maternal origin was detected in 5 of 19 tumors. The greatest degree of imbalance was detected at 11q23, distal to D11S1327 and proximal to CD3D. Age at onset of symptoms was significantly different between fathers and children (Wilcoxon rank-sum test, P < .002). Affected children had an earlier age at onset of symptoms in 39 of 57 father-child pairs (chi2 = 7.74, P < .006). However, a more conservative comparison of the number of pairs in which a child had > or = 5 years earlier age at onset (n = 33) vis-a-vis that of complementary pairs (n = 24) revealed no significant difference (chi2 = 1.42, P > .2). Whether these data represent genetic anticipation or ascertainment bias can be addressed only by analysis of a larger number of father-child pairs.

Adolescent↗
PubMed1997

Management of tumors of the parapharyngeal space.

Benign and malignant tumors can arise from any of the structures contained within the parapharyngeal space. Such tumors are very rare, however. Also, malignant tumors from adjacent areas (eg, the pharynx) can extend into the parapharyngeal space by direct growth, or distant tumors may metastasize to the lymphatics within the space. Although the history and physical examination can provide clues to the site of origin and nature of a parapharyngeal space tumor, imaging studies are more useful for defining the site of origin and extent of the mass, as well as its vascularity and relationship to the great vessels of the neck and other neurovascular structures. Surgery is the mainstay of treatment. The surgical approach chosen should facilitate complete tumor extirpation with minimal morbidity. Irradiation is administered as primary therapy in patients with unresectable tumors, poor surgical candidates, and selected other patients. Radiation therapy is also used after surgery for high-grade malignancies or when wide surgical margins cannot be achieved.

Diagnosis, Differential↗
PubMed1996

The role of apoptosis in antibody-dependent cell-mediated cytotoxicity against monolayers of human squamous cell carcinoma of the head and neck targets.

Antibody-dependent cellular cytotoxicity (ADCC) against squamous cell carcinoma of the head and neck (SCCHN) targets in the presence of human/mouse chimeric monoclonal antibodies (cMAbs), SF-25 and 323/A3, is mediated by natural killer (NK) cells. In 4-hr 51Cr-release assays with SSCHN targets in suspension, ADCC was always significantly better (P < 0.01) than that measured in parallel with the same target cells in monolayers. No differences were observed in the level of expression of the relevant antigens recognized by cMAbs on these targets. To better explain the difference, 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) monolayer and [3H]thymidine-release assays were used. Cytostasis and cell death measured in monolayer MTT assays and DNA fragmentation measured in [3H]thymidine-release assays were significantly higher (P = 0.028) than cytotoxicity determined using 51Cr-labeled SCCHN monolayers. Cell death observed in monolayer MTT assays was blocked by pretreating SCCHN targets with cycloheximide or actinomycin-D or by paraformaldehyde fixation of effector cells. The presence of apoptotic cells in monolayers co-incubated with effector cells was demonstrated in situ by labeling fragmented ends of DNA with fluorescein-conjugated dUTP and terminal deoxynucleotidyl transferase and also by flow cytometry of target cells obtained from such monolayers. Our results indicate that NK cells preferentially utilize membrane lysis (necrosis) in ADCC with tumor cell targets in single-cell suspensions. However, necrosis is not efficient in monolayers. In the presence of cMAbs, apoptosis is the primary mechanism of NK cell-mediated killing in monolayers of SCCHN targets, which were found to express receptors for tumor necrosis factor and fas ligand.

Animals↗
PubMed1996

Protective effects of interferon-gamma on squamous-cell carcinoma of head and neck targets in antibody-dependent cellular cytotoxicity mediated by human natural killer cells.

An in vitro model of antibody-dependent cellular cytotoxicity (ADCC) was established, using squamous-cell carcinoma of the head and neck (SCCHN) targets,human/mouse chimeric monoclonal antibodies (cMAbs) SF-25 and 323/A3 and human peripheral blood mononuclear cells (PBMC). We previously showed that natural killer (NK) cells are the main effector population mediating ADCC in the presence of the cMAbs. ADCC was significantly inhibited by the overnight pre-treatment of SCCHN targets with exogenous interferon-gamma (IFN-gamma). This inhibition was dose-dependent, reproducible and consistently observed with various SCCHN cell lines. SCCHN cells pre-treated with IFN-gamma had a significantly higher expression of intercellular adhesion molecule-I (ICAM-I) and major histocompatibility complex (MHC) class I antigens compared with untreated target cells. No differences in expression of the SCCHN-associated antigens on these targets or in the formation of NK-SCCHN conjugates were found, using flow cytometry. IFN-gamma-pre-treated SCCHN cells were less effective in competing with untreated targets in cold target inhibition assays and in inducing cytokine production from NK cells in co-incubation experiments. Protective effects of IFN-gamma on target cell sensitivity to lysis were blocked by pre-treatment of target cells with actinomycin-D or cycloheximide. The susceptibility of the target cells was restored by removal of MHC class I antigens from their surface by acid stripping before ADCC. Our results suggest that the decreased ADCC seen with SCCHN targets pre-treated with IFN-gamma is related to post-binding events, possibly altered signaling from targets to effector cells, and requires protein synthesis in the target cells.

Animals↗
PubMed1996

Loss of heterozygosity of the short arm of chromosomes 3 and 9 in oral cancer.

Loss of heterozygosity (LOH) on chromosomes 3p and 9p has been documented in a variety of malignancies, which suggests the presence of tumor suppressor gene loci on these chromosomes. We have studied 77 oral carcinomas for LOH using 16 microsatellite markers distributed over 5 human chromosomes. Fifty-five (71%) of these tumors showed LOH at one or more loci. A significant proportion of LOH at the informative tumors was observed at chromosomes 3p and 9p: 58% and 48%, respectively. A majority of the tumors showed losses at multiple loci on chromosomes 3p or 9p or on both. Our results suggest that tumor suppressor genes located on the short arms of chromosomes 3 and 9 may be involved in the pathogenesis of oral carcinoma. These regions of deletion observed in oral cancers overlap those reported in other neoplasms. However, we did not find any evidence of these changes in tumor margins with early pathological changes.

Carcinoma, Squamous Cell↗
PubMed1996

A long-term assessment of adjuvant chemotherapy on outcome of patients with extracapsular spread of cervical metastases from squamous carcinoma of the head and neck.

BACKGROUND: Extracapsular spread (ECS) of cervical lymph node metastases of squamous cell carcinoma from head and neck sites portend poor prognosis. Therefore, a program of combined surgery, postoperative irradiation therapy, and adjuvant methotrexate and 5-fluorouracil (5-FU) was initiated in 1982 for such patients. METHOD: All patients operated on between June 1982 and December 1992 by the full-time faculty of the Department of Otolaryngology at the University of Pittsburgh School of Medicine were eligible and reported in this trial. All patients had negative surgical margins of excision of the primary carcinoma, and histologic evidence of cervical metastases with ECS. Postoperative irradiation included 50-60 cGy for 5 to 6 weeks followed by methotrexate and 5-FU administered on an outpatient basis on days 1 and 8 every 21 days. All patients were followed for 30 or more months for evidence of recurrent disease. RESULT: A total of 371 patients met eligibility criteria. Of this group, 53 (14%) were treated with surgery only, 187 (50%) received surgery and postoperative irradiation, and 131 (35%) received surgery, irradiation therapy, and chemotherapy. The primary site, extent of nodal involvement, and stage of the three patient groups were similar. However, performance status (Karnofsky) was best in the patients who received chemoradiation (average 90) when compared with those who received surgery and irradiation (average 80) or surgery only (average 70). Absolute disease free survival rate (30 months) was 9.5% in patients treated with surgery only, 34% in patients treated with surgery plus irradiation, and 53% in patients treated with surgery, irradiation, and chemotherapy. When adjusted for patients who died of intercurrent disease with less than 30 months follow-up, survival rates became 17%, 40%, and 58%, respectively. These differences are highly significant (P < 0.001). CONCLUSION: Results of this study suggest that postoperative chemoradiation may improve survival in patients with ECS of cervical metastases. Compliance with the chemoradiation was suboptimal and suggests that improved strategy must be developed.

Aged↗