Knee and hip angle and moment adaptations during cutting tasks in subjects with anterior cruciate ligament deficiency classified as noncopers

STUDY DESIGN

Two-factor mixed-design study, with factors including group (control and noncoper) and task (sidestep, crossover, and straight).

OBJECTIVES

To compare the knee and hip joint angles and moments of control subjects and subjects with an anterior cruciate ligament (ACL) deficient knee classified as noncopers, during a sidestep, crossover, and straight-ahead task.

BACKGROUND

Subjects with ACL deficiency primarily note difficulty with cutting tasks as opposed to straight-ahead tasks. Yet, previous studies have primarily focused on straight-ahead tasks.

METHODS AND MEASURES

Fifteen subjects with ACL deficiency classified as noncopers, based on the number of giving-way episodes (>1) and global question of knee function (<60%), were included in this study. These subjects (10 male, 5 female; age range, 18-49 years) were compared to a healthy control group (7 male, 7 female; age range, 19-47 years). Position data collected at 60 Hz were combined with anthropometric and ground reaction force data collected at 420 Hz to estimate 3-dimensional knee and hip joint angles and moments. All subjects performed 3 tasks including a step and 45 degrees sidestep cut, step and 45 degrees crossover cut, and step and proceed straight. Two-way mixed-model ANOVAs were used to compare peak angle and moment variables between 10% to 30% of stance.

RESULTS

The ACL-deficient noncoper group had 1.8 degrees to 5.7 degrees less knee flexion angle compared to the control group across tasks (P<.043). The ACL-deficient noncoper group used 22% to 27% lower knee extensor moment during weight acceptance compared to the control group (P<.001). The sagittal plane hip extensor moments were 34% to 39% higher in the ACL-deficient noncoper group compared to the control group (P<.025). Hip frontal (P<.037) and transverse plane (P<.04) moments also distinguished the ACL-deficient noncoper from the control group.

CONCLUSIONS

This study suggests that individuals who do not cope well after ACL injury rely on a hip control strategy during cutting tasks.

The use of sequential MR image sets for determining tibiofemoral motion: reliability of coordinate systems and accuracy of motion tracking algorithm

The use of magnetic resonance imaging has been proposed by many investigators for establishment of joint reference systems and kinematic tracking of musculoskeletal joints. In this study, the intraobserver and interobserver reliability of a strategy to establish anatomic reference systems using manually selected fiducial points were quantified for seven sets of MR images of the human knee joint. The standard error of the measurement of the intraobserver and interobserver errors were less than 2.6 degrees, and 1.2 mm for relative tibiofemoral orientation and displacement, respectively. An automated motion tracking algorithm was also validated with a controlled motion experiment in a cadaveric knee joint. The controlled displacements and rotations prescribed in our motion tracking validation were highly correlated to those predicted (Pearson's correlation = 0.99, RMS errors = 0.39 mm, 0.38 degree). Finally, the system for anatomic reference system definition and motion tracking was demonstrated with a set of MR images of in vivo passive flexion in the human knee.

Heteroarotinoids inhibit head and neck cancer cell lines in vitro and in vivo through both RAR and RXR retinoic acid receptors

A class of less toxic retinoids, called heteroarotinoids, was evaluated for their molecular mechanism of growth inhibition of two head and neck squamous cell carcinoma (HNSCC) cell lines SCC-2 and SCC-38. A series of 14 heteroarotinoids were screened for growth inhibition activity in vitro. The two most active compounds, one that contained an oxygen heteroatom (6) and the other a sulfur heteroatom (16), were evaluated in a xenograph model of tumor establishment in nude mice. Five days after subcutaneous injection of 10(7) SCC-38 cells, groups of 5 nu/nu mice were gavaged daily (5 days/week for 4 weeks) with 20 mg/kg/day of all-trans-retinoic acid (t-RA, 1), 10 mg/kg/day of 6, 10 mg/kg/day of 16, or sesame oil. After a few days, the dose of t-RA (1) was decreased to 10 mg/kg/day to alleviate the side effects of eczema and bone fracture. No significant toxic effects were observed in the heteroarotinoid groups. All three retinoids caused a statistically significant reduction in tumor size as determined by the Student t-test (P < 0. 05). Complete tumor regression was noted in 3 of 5 mice treated with t-RA (1), 4 of 5 mice treated with 16, 1 of 5 mice treated with 6, and 1 of 5 mice treated with sesame oil. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to determine that the expression levels of RARalpha, RXRalpha, and RXRbeta were similar in the two cell lines, while RARbeta expression was higher in SCC-2 over SCC-38, and RARgamma expression was higher in SCC-38 over SCC-2. Receptor cotransfection assays in CV-1 cells demonstrated that 16 was a potent activator of both RAR and RXR receptors, while 6 was selective for the RXR receptors. Transient cotransfection assays in CV-1 cells using an AP-1 responsive reporter plasmid demonstrated that t-RA (1), 6, and 16 each inhibited AP-1-driven transcription in this cell line. In conclusion, the growth inhibition activity of the RXR-selective 6 and the more potent growth inhibition activity of the RAR/RXR pan-agonist 16 implicate both RARs and RXRs in the molecular mechanism of retinoid growth inhibition. Moreover, the chemoprevention activity and the lack of toxicity of heteroarotinoids demonstrate their clinical potential in head and neck cancer chemoprevention.

Management of cervical lymph nodes in squamous carcinomas of the head and neck

Due to the overwhelming prognostic significance of regional metastases, proper management of cervical lymph nodes in cases of squamous cell carcinoma of the head and neck is essential for an optimal outcome. Better understanding of the predictability of incidence and patterns of metastases of these tumors in recent years has led us away from the radical neck dissection as the only surgical therapeutic or staging procedure done on the neck. Recent studies suggest that selective removal of lymph node groups at risk in clinically negative necks, or modified neck dissections that save important structures, like the jugular vein, XI nerve, and sternocleidomastoid muscle, in clinically positive necks, are appropriate in many patients. Careful selection of the type of neck dissection and judicious use of postoperative radiation therapy can optimize cure rates as well as functional and cosmetic results.

Accumulation of the p53 tumor-suppressor gene product in oral leukoplakia

OBJECTIVES

(1) To determine whether the protein of the suppressor gene p53 accumulates in leukoplakia of the oral cavity in individuals who use snuff; and (2) to determine whether a correlation exists between the accumulation of p53 protein and the degree of epithelial dysplasia present in oral leukoplakia.

DESIGN

Retrospective analysis of archival tissue specimens.

SETTING

The University Hospital, a tertiary referral hospital affiliated with the Oklahoma University Medical Center, Oklahoma City, Oklahoma.

PATIENTS

In the first part of the study, biopsy specimens of leukoplakia from 12 persons who used snuff were compared with specimens from uninvolved oral mucosa of the same persons and with biopsy specimens from 12 nontobacco-using persons. In the second part of the study, accumulation of p53 protein was determined in 42 archival paraffin-embedded specimens from oral leukoplakia and correlated with the degree of epithelial dysplasia.

METHODS

Accumulation of p53 protein was assessed by immunoperoxidase staining with four different primary antibodies. Positive cells were counted in five consecutive high-power fields.

RESULTS

In part one, the average number of positive cells in the leukoplakia of snuff-users (21.89 +/- 4.33; mean +/- SE) was higher than that of normal-appearing mucosa (4.00 +/- 1.0; p < 0.05) and that of nontobacco-using controls (7.00 +/- 5.04). In part two, the average number of positive cells was higher in the moderately dysplastic (140.36 +/- 30.03) and severely dysplastic lesions (232.86 +/- 26.85) than in the mildly dysplastic lesions (14.53 +/- 3.33; p < 0.05). The correlation between the degree of epithelial dysplasia and the number of cells positive is strong (Spearman's correlation coefficient = 0.853).

CONCLUSIONS

The accumulation of p53 protein in leukoplakia of snuff-users is higher than in normal-appearing oral mucosa from both snuff-users and nontobacco-using controls. A strong correlation exists between the degree of epithelial dysplasia present in oral leukoplakia and the number of cells staining positive for p53. The accumulation of p53 protein holds potential as an intermediate end point in studies of chemoprevention of oral cancer.

Do histocompatibility antigens antigence influence the risk of head and neck carcinoma?

Associations were sought between specific histocompatibility antigens (HLA) of the human major histocompatibility complex and the incidence of head and neck squamous cell carcinoma (SqCC). Seventy sequential patients with SqCC and 217 control subjects from the same geographic region were typed for HLA-A, HLA-B, and HLA-DR loci. These results were compared. Multivariate statistical analysis using stepwise logistic regression revealed significant associations between the incidence of SqCC and HLA-B14, HLA-DR3, and HLA-DR4 as well as smoking and the sex-smoking interaction. The authors concluded that certain host factors, including genetic constitution, and behavioral characteristics (i.e., smoking) as well as tumor biology, can influence the development of SqCC. The mechanism(s) of these associations may involve as yet undefined relationships between HLA region genes and the immune response.

Sudden bilateral profound hearing loss resulting from meningeal carcinomatosis

SBPHL is a rare manifestation of hearing loss. Patients with SBPHL should have a thorough evaluation for meningeal carcinomatosis as the cause, including a complete neurologic evaluation, CT scan, and, probably, MRI. If MC is highly suspected, an LP is necessary. Because the diagnosis of MC can be confirmed only by the presence of malignant cells in the CSF, multiple LPs may be necessary to find them. Although MC should be strongly considered in the differential diagnosis of SBPHL, MC should also be considered with other patterns of eighth cranial nerve involvement, especially in patients with a history of malignancy. These patterns include unilateral hearing loss associated with tinnitus, unilateral hearing loss rapidly progressing to severe bilateral involvement, audiologic and caloric studies that show eighth cranial nerve impairment, and facial nerve palsy associated with hearing loss. The prognosis for MC is poor, although intraventricular chemotherapy and whole brain radiotherapy can provide significant palliation.

HLA class I and class II antigen expression on squamous cell carcinoma of the head and neck

We compared human major histocompatibility (HLA) class I and class II antigen expression on squamous cell carcinoma of the head and neck with that on normal mucosa. Frozen sections of a consecutive series of 30 squamous cell carcinomas were stained with the monoclonal antibodies W6/32 (class I) and anti-DR (class II) using an immunoperoxidase technique. Normal mucosa showed class I and class II expression in the basal layers only. Class I expression on tumors was diffuse in 87%, patchy in 10%, and scattered in 3%. Class II expression on tumors was diffuse in 20%, patchy in 53%, scattered in 20%, and absent in 7%. Patterns of expression did not correlate significantly with clinical parameters, including survival, except that class II diffuse and patchy patterns were found to correlate with more poorly differentiated tumors.

Advanced head and neck cancer: low-dose, split-course radiation therapy and simultaneous infusion of 5-fluorouracil and cisplatin

Twenty-three patients with advanced untreated head and neck cancer, nine patients with recurrent cancer, and six patients with recurrent cancer who underwent surgery and had postoperative persistence of tumor were treated with three 2-week courses of irradiation (1,500 cGy in 10 fractions each) concurrently with cisplatin and a 5-day infusion of 5-fluorouracil. A fourth 2-week course of irradiation (2,000 cGy in 10 fractions) brought the final tumor dose to 6,500 cGy. Twenty patients in the untreated group and three patients in the recurrent group (33%) had a complete response. There were 10 local recurrences in the untreated group (43%), seven in the recurrent group (78%), and three in the persistent group (50%). At 17 months after the start of treatment, the survival rate for the untreated patients was 51%, for the patients in the recurrent group it was 11%, and for the patients in the persistent group it was 20% (P = .03). Most patients experienced toxicity, including nausea, vomiting, weight loss, and mucositis. Clinical trials are necessary to determine whether simultaneous chemotherapy and radiation therapy is an improved method of treatment for advanced head and neck cancer.

Suction-assisted lipectomy in the management of obstructive sleep apnea

Suction-assisted lipectomy is a valuable method of aesthetic recontouring of the neck. We report the successful use of suction-assisted lipectomy as an adjunctive procedure at the time of tracheostomy in the treatment of obese patients with severe obstructive sleep apnea. This functional procedure helps to maintain tracheostomy patency during sleep.

Effect of helium concentration on experimental upper airway obstruction

This study investigates the effect of helium concentration in inspired gas on resistance to breathing during experimental upper airway obstruction. Obstruction was modeled by use of a series of four polyvinyl endotracheal tubes narrowed progressively in their midportions with C clamps. Percentage ratios of helium-oxygen gas mixtures were 0:100, 40:60, 60:40, and 80:20. Gas flow was provided by two methods: 1) nontidal flow from compressed gas tanks from which resistance was calculated from pressure and flow measurements, and 2) tidal respiratory flow from human volunteers from whom respiratory effort was evaluated by using airway pressure measurements integrated over 90-second trial periods. The results derived from both methods demonstrated that the effect of helium in reducing resistance and pressure in an obstructed airway is linear (p less than .016) and inversely proportional to helium concentration. Reductions in resistance and pressure were larger for the tighter obstructions (p less than .007). As helium was added to the gas mixture (from 0% to 80%), resistance and airway pressure measurements dropped 42% and 58%, respectively. The major conclusions are that 1) even low concentrations of helium may have therapeutic value and 2) helium is effective only for more severe obstructions.

The tooth as a foreign body in soft tissue after head and neck trauma

Thorough evaluation of dentition is important in the management of craniofacial trauma. Avulsed or fractured teeth in the pulmonary and gastrointestinal tracts can lead to serious complications that are well described. However, the penetration of avulsed teeth into soft tissues of the head and neck is unusual and may not be recognized. Two cases in which a tooth became a foreign body in these soft tissues are illustrative. One patient had bronchoscopy for possible aspiration of an avulsed maxillary canine; it was later found embedded in the premaxillary tissues. The other patient had a right mandibular molar propelled into the posterior triangle of the left side of the neck. Physicians must be aware of dental injury resulting from facial trauma and account for all teeth as part of their evaluation, keeping an open mind as to where a missing tooth might be located.

Modulation of human leukocyte antigen class I expression by gamma interferon in head and neck cancer cell lines

One possible mechanism explaining the action of interferon (IFN) on squamous cell carcinoma (SqCC) of the head and neck is the modulation of major histocompatibility antigen expression on tumor cells. We tested the ability of gamma interferon (gamma-IFN) to modulate major histocompatibility class I antigens and beta 2-microglobulin (beta 2-M) on two carcinoma cell lines derived from SqCC of the head and neck. Major histocompatibility class I antigens and beta 2-M were detected using a two-step immunochemical stain; antigen expression was quantified using flow cytometry. gamma-IFN increased constitutive antigen expression by as much as five times on both cell lines. Maximum modulation was seen within 72 hours of exposure to gamma-IFN at clinically attainable doses (10 U/mL to 100 U/mL). The presence of gamma-IFN in cell cultures was necessary for continued modulation of surface antigens. These findings suggest a possible mechanism of action and encourage further clinical trials with gamma-IFN.

Epistaxis: medical versus surgical therapy: a comparison of efficacy, complications, and economic considerations

A retrospective review of 4 years experience with over 32 epistaxis patients requiring hospitalization and using a standard medical or surgical therapy for control is presented. Medical therapy included the use of anterior nasal packing alone or in association with intranasal and nasopharyngeal balloon tamponade. Surgical therapy, for the most part, consisted of ethmoid and/or internal maxillary artery ligations. Most patients were treated initially with packing and balloons. Fifty-two percent of the group failed this therapy and required ligations for control. The patients who did not come to operation had fewer complications, a shorter average hospital stay, and lower average cost of hospitalization without increased risk of future epistaxis. An analysis is made comparing the results, complications, and financial implications of these two approaches.

Further clinical experience with the silicone tracheal cannula in obstructive sleep apnea

We report on the perioperative and postoperative course of 47 patients with severe obstructive sleep apnea, who underwent tracheostomy by use of a silicone tracheal cannula developed by Dr. William Montgomery. Our initial experience with the first 20 of these patients (presented in 1982) was quite favorable because of the ease of insertion and care, a high degree of patient acceptance, and infrequent complications. With our current sample, larger experience, and more prolonged follow-up, we noted that symptomatic granulation tissue formation, with or without wound infection, occurred more frequently than was initially appreciated. In 21% (10 of 47) of the cases, the only way to resolve this problem was to remove this device and replace it permanently with a metal (or other type) tracheostomy tube. Other complications included tracheal narrowing and cannula malpositioning and fragmentation. This full report lists in detail the incidence of complications associated with our use of this cannula and modifications which may lessen these.

Infrared Astronomy After IRAS

The 250,000 sources in the recently issued Infrared Astronomy Satellite (IRAS) all-sky infrared catalog are a challenge to astronomy. Many of these sources will be studied with existing and planned ground-based and airborne telescopes, but many others can no longer even be detected now that IRAS has ceased to operate. As anticipated by advisory panels of the National Academy of Sciences for a decade, study of the IRAS sources will require the Space Infrared Telescope Facility (SIRTF), a cooled, pointed telescope in space. This instrument may be the key to our understanding of cosmic birth-the formation of planets, stars, galaxies, active galactic nuclei, and quasars. Compared with IRAS and existing telescopes, SIRTF's power derives from a thousandfold gain in sensitivity over five octaves of the spectrum.

Early Results from the Infrared Astronomical Satellite

For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to work only on cloudy afternoons. IRAS observations are serving astronomers in the same manner as the photographic plates of the Palomar Observatory Sky Survey; just as the optical survey has been used by all astronomers for over three decades, as a source of quantitative information about the sky and as a "roadmap" for future observations, the results of IRAS will be studied for years to come. IRAS has demonstrated the power of infrared astronomy from space. Already, from a brief look at a miniscule fraction of the data available, we have learned much about the solar system, about nearby stars, about the Galaxy as a whole and about distant extragalactic systems. Comets are much dustier than previously thought. Solid particles, presumably the remnants of the star-formation process, orbit around Vega and other stars and may provide the raw material for planetary systems. Emission from cool interstellar material has been traced throughout the Galaxy all the way to the galactic poles. Both the clumpiness and breadth of the distribution of this material were previously unsuspected. The far-infrared sky away from the galactic plane has been found to be dominated by spiral galaxies, some of which emit more than 50 percent and as much as 98 percent of their energy in the infrared-an exciting and surprising revelation. The IRAS mission is clearly the pathfinder for future missions that, to a large extent, will be devoted to the discoveries revealed by IRAS.

Immunomodulatory activity in regional lymph nodes

This study is, to our knowledge, the first attempt to evaluate cellular immune mechanisms in regional lymph nodes of patients with head and neck cancer. Twenty lymph nodes from eight patients with stage III-IV squamous cell carcinoma were evaluated using an in vitro culture system. The T-cell mitogenic (concanavalin A) response of patients' peripheral blood mononuclear cells was modulated by the addition of cells from regional lymph nodes removed at neck dissection. Modulatory activity showing augmentation was significantly correlated with the size of the primary tumor and histopathologic grade of the tumor. Modulatory activity did not correlate with the histologic pattern of lymph node reactivity. Although these relationships suggest that regional immunity may be important in tumor-host interactions, further study is necessary to establish their biologic and prognostic importance.

Jupiter: Its Infrared Spectrum from 16 to 40 Micrometers

Spectral measurements of the thermal radiation from Jupiter in the band from 16 to 40 micrometers are analyzed under the assumption that pressure-broadened molecular hydrogen transitions are responsible for the bulk of the infrared opacity over most of this spectral interval. Both the vertical pressure-temperature profile and the molecular hydrogen mixing ratio are determined. The derived value ofthe molecular hydrogen mixing ratio, 0.89 +/- 0.11, is consistent with the solar value of 0.86.

Black paints for far infrared cryogenic use

A cryogenic paint which remains absorptive throughout the infrared has been developed. The paint exhibits excellent surface stability at liquid helium temperature and is resistant to abrasion and flaking. Measurements in a specially constructed cryogenic integrating sphere indicate that the paint is ~92-100% absorptive in the 70-130-micro range. Additional broadband measurements at 60 micro-130 micro, 18 micro-25micro, and 400 micro-1 mm indicate that the paint is ~95% absorptive.

Far-Infrared Observations of the Night Sky

We have flown a telescope cooled to liquid-helium temperatures and made far-infrared observations of the night sky. A gallium-doped germanium detector, sensitive from 5.2 to 130 micrometers, detected a minimum signal of 10(-9) watt per square centimeter per steradian referred to 100 micrometers. The origin of this signal can be instrumental, atmospheric, interplanetary, or interstellar. We can place a firm upper limit on the color temperature of a dilute cosmic background flux.