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Biomedical subjects

J M Stein

Publications and source records attributed to J M Stein.

At least 19 recordsLinked to original sources
PubMed2000

Effect of mechanical reinforcement on stability of the rotary door flap laryngotracheal reconstruction: a canine study.

OBJECTIVE/HYPOTHESIS: The rotary door flap (RDF) laryngotracheal reconstructive procedure uses a 180 degrees rotation of the sternohyoid muscle into a laryngofissure. Despite excellent clinical results, there are concerns of flap inspiratory prolapse. This study examined RDF stability and the efficacy of ancillary materials in providing additional support. METHODS: Seventeen dogs underwent endoscopic induction of subglottic stenosis and delayed RDF reconstruction. Animals received 1) traditional RDF (control), 2) RDF with titanium screen implant, 3) RDF with porous polyethylene implant, or 4) RDF with hydroxyapatite cement (HAC) injection. Four weeks postoperatively the flaps were tested for stability. On qualitative assessment, endoscopic visualization was completed with quiet respiration and then following endotracheal tube occlusion. On quantitative assessment, after animals were killed, the RDF segment was isolated and subjected to negative pressure (maximum pressure, -50 mm Hg). The pressure-causing collapse was measured. RESULTS: In the traditional RDF animals (control), five of six flaps were stable in vivo and with negative pressures. In the titanium screen, porous polyethylene group, and HAC groups, respectively, four of four, three of four, and two of three flaps were stable in vivo and under negative pressure. Flaps that demonstrated instability had granulation, dehiscence, and poor healing. These occurred in 1 of 6 animals in the traditional RDF group and in 2 of 11 animals in the implant groups. In addition, 13 of 24 animals assigned to the implant groups died, compared with 2 of 8 of those in the traditional RDF group. CONCLUSIONS: The RDF is stable and maintains the airway under physiological conditions. Support materials did not improve stability, render flap harvest more difficult, or increase morbidity and mortality.

Animals↗
PubMed1998

Structural stability of the rotary door myocutaneous flap.

This canine study examines the structural stability of extensive laryngotracheal reconstruction with the sternohyoid myocutaneous rotary door flap (RDF) and modifications of the RDF with subdermal collagen and collagen hydroxyapatite matrix. The postreconstruction stability of the RDF and these modifications were tested and compared by measuring immediate postmortem airway stability during application of negative intraluminal pressures. Comparisons between controls and experimental specimens demonstrated that the RDF provides structural stability to secure airway patency under physiologic pressures. Biocompatible matrix adds further structural support in maintenance of the reconstructed lumen. This study validates that the RDF provides adequate rigid support for extensive laryngotracheal reconstruction without the requirement of skeletal support.

Animals↗
PubMed1997

Transnasal transseptal endoscopic approach to the sphenoid sinus.

A modified transseptal approach to the sphenoid sinus and pituitary gland utilizing rigid endoscopy has been developed by the Departments of Otolaryngology, Plastic Surgery, and Neurosurgery at The Cleveland Clinic Foundation. When compared with alternate approaches or the nonendoscopic transseptal procedure, the modified approach provides better visualization and increased illumination of the surgical sites. Other advantages include a decrease in operating time, dissection, bleeding, and postoperative morbidity without compromising nasal function in the postoperative period.

Adenoma↗
PubMed1997

Endoscopic approach for benign tumor ablation of the forehead and brow.

Resection of benign tumors of the forehead and brow raises aesthetic concerns. An endoscopic subperiosteal approach to benign bony and soft-tissue tumors in the supraorbital and frontotemporal regions permits extirpation of these masses without producing visible facial scars. Therefore, this technique was used for tumor resection in 4 patients. This procedure demonstrated magnified visualization of the masses, and safe access for excisional biopsy and bony contouring. In addition to more acceptable surgical scars, patients experienced no significant postoperative morbidity and a reduced incidence of swelling, discomfort, and scalp anesthesia. Therefore, we conclude that the endoscopic subperiosteal approach is a favorable alternative for resection of suitable tumors.

Adult↗
PubMed1996

Tumor reactivity of immune T cells in short-term culture.

The adoptive transfer of immune T cells is capable of mediating the regression of established neoplasms in a variety of animal tumor models. The antitumor activity is invariably proportional to the number of cells transferred, thus methods to expand immune cell number while maintaining therapeutic efficacy have been extensively investigated. Here we demonstrate that a short-term culture of immune T cells can amplify the T cell number and enhance the therapeutic reactivity against established pulmonary tumor, while maintaining immunological specificity. In contrast, the therapeutic reactivity of immune T cells against established subcutaneous tumor is diminished by short-term culture. While cultured immune T cells are not cytotoxic in a 4-h Cr-release assay, they do specifically secrete interferon gamma upon stimulation with tumor cells. T cells cultured after a single exposure to tumor are even more active against pulmonary tumor than T cells cultured from mice immunized repeatedly. This culture system can rapidly induce T cell proliferation and differentiation into mature effector cells, and the resulting cells demonstrate an enhanced ability to treat visceral metastases, but a decreased ability to treat subcutaneous tumor. Thus T cells cultured after a single exposure to tumor represent an ideal population of cells for use in human adoptive immunotherapy trials.

Animals↗
PubMed1996

The relationship of the guided gingival frame to the provisional crown for a single-implant restoration.

This article discusses and defines the use of the provisional crown to encourage gingival growth to provide an ideal frame for a single-tooth implant prosthesis. Both the rationale and the technique are presented. The successful use of an osseointegrated implant to support a fixed prosthesis is an accepted treatment modality in both the biologic and clinical dental communities. The clinical examination, the radiographic survey, and diagnostic casts all contribute to achieving an optimal esthetic result, but the final image may continue to be elusive until the healing of the second-stage surgery when the gingiva can be evaluated. The gold standard of success is providing an inconspicuous result.

Crowns↗
PubMed1995

A comparative study of the microbiologic effectiveness of chemical disinfectants and peroxide-neutralizer systems.

We evaluated the antimicrobial activity of chemical and hydrogen peroxide-neutralizer contact lens disinfection systems. The acute activity, storage, and recontamination potential of the two disinfection methods were compared by challenging the disinfectants with Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida spp., and Aspergillus fumigatus. Chemical disinfectants preserved with polyquaternium-1 and polyhexamethylene biguanide and hydrogen peroxide-neutralizer systems with no additional preservatives were tested. Additionally, lens cases from patients using both systems were evaluated. Lens cases from patients using peroxide-neutralizer systems tended toward heavier contamination (31.8%) than the cases disinfected with a chemical system (20.3%, P = 0.16). The laboratory results showed that the differences in activity of chemical and peroxide-neutralizer systems was not statistically significant at the disinfection times against Staphylococcus epidermidis, S. marcescens, Candida parapsilosis, and A. fumigatus (P = 0.1037 to P = 0.5412). A statistical difference was shown against C. albicans (P = 0.0176) in favor of the peroxide-neutralizer systems. The reverse was true during storage. Although the chemical disinfectants maintained the population of microorganisms, the bacteria and yeast increased to over 10(7) CFU/mL in neutralized peroxide systems. Overall, the results emphasize the importance of contact lens products containing preservatives for lasting protection from microorganisms.

Biguanides↗
PubMed1994

On the selection and preparation of a wire for the labial bow of an orthodontic retainer.

The Hawley retainer is often prescribed by the practitioner for part-time wear during the retentive period subsequent to a program of active, maxillary arch, orthodontic therapy. The labial bow of this retainer, while engaged, may be subjected to contact forces from sources other than the maxillary anterior teeth. The bow also experiences small deformations during placement and removal of the appliance from the oral cavity. Potential failures of the bow are: 1) inelastic bending from individual masticatory actions that change its as-prepared shape; and 2) fracture due to fatigue arising from many cycles of removing and replacing the retainer. Reported in this paper, a sequel to a previous article, are the outcomes of two experiments and a nonparametric analysis that led to the development of a set of recommendations pertaining to the selection of the wire and preparation of the labial bow. Controlled variables in this study were as-received size, alloy and temper of the wire, and heat-treatment following fabrications of bow-specimens.

Chromium Alloys↗
PubMed1994

Compliance: a comparison of three lens care systems.

Noncompliance is an important health care issue. This report presents results of assessments of three different lens care systems and directly compares compliance with each and the potential impact on patients' safety and comfort. Methods involved trained interviewers, patient demonstrations, a panel of experts, statistical analyses, and an assessment of the clinical significance of patients' noncompliant behaviors. These methods were able to discriminate among the levels of compliance with the lens care systems assessed. The three regimens were comparable regarding steps significant to lens wearing comfort with approximately one-third of all patients noncompliant with at least one of these steps. The same cannot be said regarding safety, however, with the incidence of noncompliance at 55, 84, and 91% for the three regimens. These findings indicate that simplicity alone cannot overcome noncompliance and the design of the system is an important consideration when making recommendations regarding lens care.

Adolescent↗
PubMed1993

Compliance and contact lens care: a new assessment method.

We propose a new method for assessing and quantifying compliance with contact lens care regimens. We recommend two separate procedures: one in which trained interviewers examine the actual lens care techniques used by typical, experienced patients and another in which clinicians rate each step in a lens care regimen as to the level of risk to the patient's comfort and safety if noncompliance with that step occurs. When combined, these steps quantify compliance with the regimen under investigation. The method can be used to assess the incidence of compliance with the regimen in question, and to compare compliance across dissimilar care systems. In our investigation, we applied the method to a multi-purpose solution regimen which has been marketed as being simple to use and, therefore, the correct care procedures are more likely to be complied with. However, we found that patient compliance with this regimen was equivalent to that found in an earlier study of an oxidative (hydrogen peroxide) care system, with noncompliance posing significant risks to both safety and comfort. The results indicate that 91% of patients were noncompliant with one or more of the steps in the lens care regimen that were judged to be clinically significant safety risk factors. Factors which posed significant risks to comfort were less likely to induce noncompliance. Only 34% of patients failed to follow one or more of the steps judged to provide clinically significant risks to comfort. The authors conclude that multi-purpose or simplified regimens are not acceptable substitutes for careful patient training and frequent follow-up.

Adolescent↗
PubMed1993

A new method to assess contact lens care compliance.

Failure to comply with contact lens care instructions is a conspicuous finding among both symptomatic and asymptomatic patients. We used a new methodology to quantify the extent of noncompliance and its clinical significance among 170 soft lens wearers. All patients were interviewed and asked to demonstrate their lens care practices. The significance of deviations from package insert instructions was assessed by 22 ophthalmologists and optometrists with regard to potential impact on safety and comfort. Virtually all patients were noncompliant with at least one required procedure. Noncompliant behavior that could significantly affect safety was more common and judged by practitioners to be of more concern than deviations that could affect comfort. Fifty-seven percent of the patients used disinfection procedures that could seriously affect safety. Overall, the study methodology was found to be very effective both for quantifying noncompliance and for evaluating its clinical significance.

Adolescent↗
PubMed1992

Exercise tolerance in panic disorder patients.

Sixteen panic patients and fifteen normal controls performed submaximal exercise testing on a bicycle ergometer. Only one patient subject panicked. Biochemical, physiological, and psychological data showed similar exercise tolerance in both patients and controls. Exercise-induced distress and lactate increment do not appear to cause panic attacks.

Adult↗
PubMed1992

The restoration of functional occlusion and esthetics.

Severe occlusal destruction, whether it results from attrition, abrasion, or erosion, must be met with definitive diagnosis and treatment. This case report illustrates the step-by-step diagnosis and treatment of a patient with severe occlusal wear. Restoration of a functional occlusion and esthetics involved endodontic treatment, reestablishment of the vertical dimension of occlusion, osseous periodontal surgery, and placement of single-tooth cast glass-ceramic crowns.

Crowns↗
PubMed1991

An acetylation method for the quantification of membrane lipids, including phospholipids, polyphosphoinositides and cholesterol.

A method for the quantification of membrane lipids by acetylation with [3H]acetic anhydride is described. A standard lipid, labelled with 14C or 32P, is added to the sample and is simultaneously acetylated. The 3H/14C or 3H/32P ratios obtained in the acetylated lipids are proportional to the initial lipid concentration. The method has been used to quantify cholesterol, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in amounts between 2 and 10 nmol.

Acetylation↗
PubMed1991

Ectocytosis caused by sublytic autologous complement attack on human neutrophils. The sorting of endogenous plasma-membrane proteins and lipids into shed vesicles.

During sublytic complement attack on human neutrophils, plasma-membrane vesicles are shed from the cell surface as a cell-protection mechanism. By using surface-iodinated neutrophils it was found that less than 2% of surface label was recovered in shed vesicles under conditions where 40% of complement component C9 was shed. SDS/PAGE of 125I-labelled shed vesicles and plasma membranes showed differences in iodination pattern, demonstrating the sorting of membrane proteins into the shed vesicles. Analysis of 32P-labelled phospholipids after labeling of neutrophils with [32P]Pi before sublytic complement attack showed the presence of phosphatidic acid, phosphatidylcholine, phosphatidyl-ethanolamine, phosphatidylinositol and polyphosphoinositides in shed vesicles. Quantitative analysis using [3H]acetic anhydride-labelling method showed that the molar proportions of phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine and sphingomyelin were the same in shed vesicles as in plasma membranes. In contrast, the molar proportions of cholesterol and diacylglycerol relative to sphingomyelin were almost twice those found in plasma membranes. The data demonstrate the existence of protein and lipid sorting mechanisms during the formation of shed vesicles when neutrophils are subject to sublytic complement attack. The term 'ectocytosis' is proposed to describe triggered shedding of right-side-out membrane vesicles from the surface of eukaryotic cells.

Autoradiography↗
PubMed1990

[Functional prosthetic treatment for the partially edentulous with osseointegrated implants].

The edentulous distal extension area has generally been restored with a removable partial denture. Some clinicians report long term success with a fixed partial denture containing distal cantilever pontic(s). Conversely, other clinicians find that the aforementioned is suspect at best due to the unusual stress demands placed on the abutment teeth by the pontic(s). When a tooth borne fixed partial denture is used to restore a long edentulous span, reports vary relative to long term success. The advent of osseointegrated implants as tooth substitutes may reduce and often eliminate particular compromised fixed or removable partial denture designs. Disregarding other problems that may or may not coexist with any remaining natural teeth in the same arch is a fallacious overview. It is paramount that future problems must be incorporated in any and all treatment plans at the same time the initial plan is formulated. Recent surveys reveal that a fewer percent of the population are becoming completely edentulous. Therefore, it is apparent that an increase in the treatment of the partially edentulous implant patient is a realistic consideration for all restorative dentists. However, it is ironic that those patients with the most severely debilitated conditions may often not be candidates for implant procedures. It is mandatory that a detailed explanation of any compromises and drawbacks to the final result must accompany the initial diagnostic presentation to the patient. It is quite evident that the dentist is confronted with a paradox that is difficult to resolve.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Implantation, Endosseous↗