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Biomedical subjects

K H Calhoun

Publications and source records attributed to K H Calhoun.

At least 37 records · Page 2Linked to original sources
PubMed1996

Skull base allergic fungal sinusitis with abducens palsy in the third trimester.

Allergic fungal sinusitis (AFS) usually follows a slow course, but bone erosion including that of the skull base can be seen. Patients may present with intracranial extension mimicking a cranial base neoplasm. We describe a 21-year-old pregnant female initially seen at 27 weeks gestation with a complete right sixth nerve paralysis. MR imaging showed an apparent nasopharyngeal neoplasm invading both temporal lobes. Further evaluation revealed typical findings of fungal sinusitis on both CT and MR images. Biopsy results fulfilled the diagnostic criteria of AFS, and after endoscopic treatment the sixth nerve palsy quickly resolved. Although abducens palsy has been reported with acute bacterial sinusitis and with mucocele, and limitation of eye motility has been described with orbital involvement by AFS, we are unaware of any prior reports of true cranial nerve palsy associated with proven AFS. Our patient had no evidence of mucocele or of bacterial infection. The palsy in this case was presumably the result of compression of the cavernous sinus. The patient's pregnancy made decision making regarding imaging and surgical intervention complex. Mother and child are alive and well 31 months after surgery.

Case Reports↗
PubMed1996

Effect of hyperbaric oxygenation on existing oral mucosal carcinoma.

Hyperbaric oxygen therapy (HBO) is used to treat some complications of head and neck carcinoma treatment. Several patients treated with HBO have had rapid growth of a clinically cured squamous cell carcinoma. Prior studies have produced conflicting evidence about the effect of HBO on tumor growth. This study was undertaken to determine the effects of HBO on established squamous cell carcinoma. Forty Golden Syrian hamster cheek-pouch carcinomas were induced with the established chemical carcinogen 9,10-dimethyl-1,2-benzanthracene. Twenty hamsters underwent 30 HBO dives for 60 minutes each to 2.81 atm, while 20 served as controls. At necropsy, animals receiving HBO therapy had significantly smaller tumors (P < .05) and showed a trend toward fewer cervical metastases (P < .06). HBO therapy with coexistent carcinoma inhibited the established tumor's growth.

Animals↗
PubMed1995

Gene expression of markers associated with proliferation and differentiation in human keratinocytes cultured from epidermis and from buccal mucosa.

Normal keratinocytes from epidermis and from buccal mucosa underwent dissimilar stages of differentiation in the same culture medium and responded differently to changes in the composition of the medium. Manifestations of these variations were examined in terms of the expression at the mRNA level (as measured by reverse transcriptase-polymerase chain reaction) of three regulatory genes (cdc2, c-myc, and p53) and five that encode structural proteins (keratins K5, K10 and K13, involucrin, and filaggrin), in three growth-medium formulations. The culture conditions enhanced or retarded maturation; the observed alterations in gene expression correlated with these changes. Except for the proliferation genes, the non-keratinizing buccal mucosa generally responded more weakly than the orthokeratotic epidermis to culture-medium supplementation favouring differentiation. Gene expression in cultured keratinocytes reflected their ability to differentiate in vivo; genes were expressed even when the corresponding protein was not seen in vitro. Although keratin K10 is not prevalent in the buccal mucosa nor keratin K13 in the epidermis, the genes for both were found to be expressed in both tissues.

Calcium↗
PubMed1995

Pseudoepitheliomatous hyperplasia mistaken for cancer after delayed reconstruction.

Pseudoepitheliomatous hyperplasia (PEH) arises in areas of chronic inflammation and can be mistaken for squamous cell carcinoma, leading to unnecessary removal of more tissue. We present a study of 21 patients having delayed reconstruction of defects left by Mohs micrographic surgery (MMS) to remove facial skin cancers. Reconstruction was done at an average of 6 days after MMS. Four of these 21 patients (19%) had PEH in the wound margins. Presence of PEH did not correlate with age, sex delay in reconstruction, frequency of wound care, size or location of the defect, type of tumor, or smoking status. During an average 24-month follow-up, none of these four patients had tumor recurrence, suggesting that the benign diagnosis of PEH was correct. We detail the histologic features of PEH, and describe techniques for minimizing confusion with squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1995

Complications of endoscopic sinus surgery in a residency training program.

Endoscopic sinus surgery (ESS) is now taught in most otolaryngology residency programs in the United States. However, this is technically challenging surgery and concerns exist regarding patient safety early in the surgeon's learning curve. The authors reviewed 193 cases of ESS performed by residents, under faculty supervision at our program, between 1987 and 1992. Sixty-seven percent of patients underwent bilateral anterior ethmoidectomy, 40% had bilateral total ethmoidectomy, and 44% had bilateral middle turbinate reduction. The overall complication rate was 22% and included one major complication. Synechiae accounted for 50% of minor complications. There was no correlation between middle or inferior turbinate reduction and the formation of synechiae. Posterior ethmoidectomy was not associated with a significant increase in complications. We conclude that ESS can be safely performed by otolaryngology residents in carefully structured and supervised training programs.

Adolescent↗
PubMed1994

Intelligibility of tracheoesophageal speech among naive listeners.

Tracheoesophageal (TE) speech is now the most common method of voice rehabilitation after total laryngectomy. The speech intelligibility of laryngectomees who use TE speech as their primary mode of communication was evaluated by 20 "naive" listeners. Two speech intelligibility tests were administered using phonetically balanced rhyming words or lists of spondee words. The overall intelligibility for the group of laryngectomees was 76%, with a wide range of variability among the individual TE speakers. We concluded that TE speech is significantly less intelligible to naive listeners than normal laryngeal speech; further refinement of voice rehabilitation for laryngectomees is needed.

Female↗
PubMed1994

Management of the thyroid isthmus in tracheostomy: a prospective and retrospective study.

The thyroid isthmus is often encountered while a tracheostomy is being performed. This study details retrospective and prospective comparison of electrocautery division of the isthmus with older techniques. In this study, electrocautery division of the thyroid isthmus during tracheostomy is faster and as safe as other techniques with respect to blood loss, perioperative complications, and airway outcome.

Blood Loss, Surgical↗
PubMed1994

Distant metastases from head and neck squamous cell carcinomas.

Distant metastases (DMs) occurred in 83 (11.4%) of 727 retrospectively studied head and neck cancer patients. Primary tumor location and initial treatment did not influence DM development; larger primaries (P < .04) or more extensive neck disease (P < .007) more often caused DMs. Initial diagnosis to DMs averaged 11.7 months (range, 0 to 60 months), with 84% diagnosed within 24 months. With the exception of laryngeal primaries, no facet of tumor, host, or initial treatment influenced where or how rapidly DMs developed. Lung was the most common DM site (83.4%), then bone (31.1%) and liver (6.0%). Survival with DMs averaged 4.3 months (range, 1 day to 2.7 years); 86.7% died within 1 year. This report yields the following conclusions: 1. Initial tumor size and neck disease are the only predictors of DMs. 2. DMs usually occur within 2 years of the initial diagnosis. 3. Lung is the most common DM site, making chest x-ray the most effective DM screen. 4. Survival with DMs is usually less than a year.

Adult↗
PubMed1993

Multicenter comparison of clarithromycin and amoxicillin in the treatment of acute maxillary sinusitis.

PURPOSE: To compare the safety and efficacy of orally administered clarithromycin, a new macrolide antimicrobial, and amoxicillin in the treatment of patients with acute maxillary sinusitis. PATIENTS AND METHODS: One hundred forty-two consecutive outpatients treated at four primary care centers for acute maxillary sinusitis were randomly assigned to receive oral clarithromycin (500 mg twice daily) or oral amoxicillin (500 mg three times daily) for 7 to 14 days. Clinical and roentgenographic responses to the antibiotic therapy were determined within 48 hours after the last dose and 6 weeks later. RESULTS: The success rates of clarithromycin and amoxicillin were comparable. A clinical success rate of 91% and a roentgenographic success rate of 78% were achieved in the clarithromycin group at the final visit; comparable results for the amoxicillin group were 89% and 92%, respectively. Differences between the two groups were not statistically significant (P = .766 and .064, respectively). No serious adverse events were reported, although both drugs caused mild gastrointestinal distress. Dropout rates were low in both groups: 3% for clarithromycin and 4% for amoxicillin. No clinically significant changes in laboratory studies were observed in either group. CONCLUSION: Clarithromycin twice daily is effective and well tolerated in patients with acute maxillary sinusitis.

Acute Disease↗
PubMed1992

Chin position in profile analysis. Comparison of techniques and introduction of the lower facial triangle.

Many patients undergoing rhinoplasty can benefit from chin augmentation, yielding a more balanced appearance. Preoperative facial analysis identifies patients with retrusive chins and suggests optimal chin position. Current profile analysis methods depend on subnasale position (Legan's angle) or require estimation of bony landmarks from soft-tissue photographs (Goode's alar crease perpendicular, Gonzalez-Ulloa's zero meridian, and Merrifield's Z-angle). We describe a technique for determining ideal chin position using soft-tissue landmarks. We compare this technique with Legan's, Goode's, Gonzalez-Ulloa's, and Merrifield's techniques in 35 women and conclude that this method provides accurate and rapid determination of ideal chin position.

Adult↗
PubMed1992

Age-related changes in oral sensation.

Oral sensation (including two-point discrimination, oral stereognosis, vibrotactile detection, somesthetic sensitivity, proprioception, and thermal sensitivity) was studied in 60 healthy adults in five age categories: 20 to 34, 35 to 49, 50 to 64, 65 to 79, and 80 years and above. Thermal and somesthetic sensitivity as well as proprioception did not change with age. Ability to differentiate tactile and vibratory sensation on the lip decreased after age 80 (P less than .01), but vibration detection on the soft palate did not change. Stereognostic ability remained good up to age 80, and then declined for four of the nine shapes tested (P less than .01). Two-point discrimination deteriorated on the upper lip (P less than .01), on the cheeks (P less than .02), and on the lower lip (P less than .06). Two-point discrimination on the tongue and palate did not change. It was noted that oral sensation remained good with aging, showing only a slight decline in function after age 80.

Adult↗
PubMed1992

Ornithine decarboxylase activity in tumor and normal tissue of head and neck cancer patients.

Tumorigenesis requires increased biosynthesis of polyamines and elevated levels of ornithine decarboxylase, which is the rate-limiting enzyme in the polyamine synthesis pathway. Previous animal studies have noted a marked increase in ornithine decarboxylase after exposure to tumorigenic stimuli and that pretreatment with vitamins A and E provides protection against the carcinogenic action. However, studies of ornithine decarboxylase activity in human oral cavity carcinoma have not been as specific. The goal of this study was to determine whether a specific difference in ornithine decarboxylase activity occurs in tumor versus adjacent normal tissue in head and neck squamous cell carcinoma patients. Ornithine decarboxylase activity was measured in 30 consecutive head and neck cancer patients undergoing surgical therapy. Ornithine decarboxylase levels were found to be significantly elevated in tumor tissue samples when compared to adjacent normal mucosa samples (P less than .004). This finding confirms the previous findings noted in animal models and implies that the protective effects of vitamins A and E will extend to human head and neck cancers.

Carcinoma, Squamous Cell↗