Biomedical subjects
Publications and source records attributed to J E Lewis.
This report describes a technique for the reconstruction of a patellar tendon-tibial tubercle deficiency. This technique uses an easy-to-harvest, low-morbidity graft (autogenous quadriceps tendon), while allowing aggressive rehabilitation as a result of the strength of the graft.
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We reviewed the clinical and pathologic features of 47 laryngeal cartilaginous tumors treated at the Mayo Clinic. This represents the largest reported series of these tumors. The patient group consisted of 36 men (77%) and 11 women (mean age, 63 years; range, 44 to 91 years). The tumors included 44 chondrosarcomas, all low-grade, and 3 chondromas. The overall 5-year survival was 90.1%, which did not differ significantly from the expected survival. Laryngectomy was performed as primary treatment for chondrosarcoma in 6 patients. Of the patients with chondrosarcoma, 40% had tumor recurrence or symptomatic tumor progression at an average of 4.5 years after diagnosis. Only 15 of the patients with chondrosarcoma (34%) required total laryngectomy. There were no metastases, and 4 patients died of local disease (all received treatment before 1960). At latest follow-up, 34 patients with chondrosarcoma (77%) were alive without disease or had died of other causes. We conclude that laryngeal chondrosarcoma can be treated with conservative surgery in most cases, both initially and for recurrent disease.
Between 1974 and 1992, 32 patients with pathologically diagnosed angiosarcoma of the head and neck were evaluated at our institution. The primary treatment group consisted of 24 patients who had the initial diagnosis made or confirmed at our institution, and the other 8 patients formed the salvage group. There were 23 men and 9 women. The median age in the primary treatment group was 63 years (range 18 to 91 years). The overall median survival among the primary group patients was 4.8 years, and the 3-year survival was estimated to be 57% (95% confidence interval 39% to 84%). The median follow-up was 2.1 years (range 83 days to 9.7 years). Patients who had tumors less than 7.0 cm in diameter and tumors with invasion only to the subcutaneous tissues had better overall survival and longer time to first adverse event. Diploid DNA content was a significant favorable prognostic factor for time to first adverse event. Mitotic activity was of borderline significance with both end points. Patients who had tumors of less than 1.5 cm were treated successfully with surgery alone. Patients treated with combined surgery and radiotherapy also tended to do better. Because most patients in whom regional recurrences developed had tumors larger than 7.0 cm, we conclude that patients with tumors of this size may benefit from regional neck node dissection at the time of primary excision or from elective neck irradiation.
Bone remodeling in response to force requires the coordinated action of osteoblasts, osteoclasts, osteocytes, and periodontal ligament cells. Coordination among these cells may be mediated, in part, by cell-to-cell communication via gap junctions. This study tests the hypothesis that the regulation of expression of connexin 43, a gap junction protein, is part of the transduction mechanism between force as applied to bone during orthodontic tooth movement and bone remodeling. To test this hypothesis, we examined connexin 433 expression in a rat model system of experimental tooth movement. To establish the model, we extracted maxillary first molars to initiate supra-eruption of opposing mandibular molars. The rats were killed at 0, 6, 12, 24, and 48 hrs post-extraction. The mandibles were removed, demineralized, and embedded in paraffin. To localize connexin 43 protein and mRNA, we used a specific antibody for immunohistochemistry and a specific cDNA probe for in situ hybridization. Western and Northern blot analyses were used to assess the specificity of the connexin 43 antibody and cDNA probe, respectively. We found connexin 43 protein expressed by osteoclasts (++ ++) and periodontal ligament cells (++ +) in compression zones, and by osteoblasts (++ ++) and osteocytes (++ ++) in tension zones of the periodontal ligament. In addition, connexin 43 mRNA was found in some bone and periodontal ligament cells. Connexin 43 protein was found, by densitometric analysis, to be higher in the periodontal ligament after exposure to force compared with controls (P < 0.001). The number of osteocytes expressing connexin 43 48 hrs after molar extraction was also significantly greater in bone subjected to tension when compared with controls (P < 0.001). The results of this study support the hypothesis that connexin 43 plays a role in the coordination of events during experimentally induced alveolar bone remodeling.
BACKGROUND: Salivary duct carcinoma (SDC) is a high grade aggressive malignancy of the major salivary glands. Clinical and pathologic features that may be predictive of survival are not well delineated. The microscopic features of SDC are remarkably similar to those of mammary ductal carcinoma, raising the question of whether these tumors share antigenic or hormonal features. METHODS: We reviewed the clinical and pathologic characteristics of 26 cases of SDC treated at the Mayo Clinic from 1960 to 1989. Immunoperoxidase studies and flow cytometry were performed in 25 and 24 cases, respectively. RESULTS: The study population consisted of 22 men and 4 women (mean age, 66 years). The parotid gland was involved in 23 patients and the submaxillary gland in 3. Five of 24 tumors studied were diploid (21%), and 19 (79%) were nondiploid. Nine tumors (35%) recurred locally and 16 (62%) metastasized distantly; 20 patients (77%) died of disease at a mean interval of 3 years after diagnosis. Female sex was the only significant negative prognostic factor analyzed, but positive nodal status approached significance. Paraffin-section immunostaining showed positive reactions for epithelial membrane antigen (100%), keratin (AE1/AE3) (88%), alpha-lactalbumin (88%), GCDFP-15 (76%), and carcinoembryonic antigen (72%); S-100 protein was rarely detected (4%). Stains for estrogen receptor were uniformly negative, but one tumor was positive for progesterone receptors. CONCLUSIONS: The prognosis for SDC is dismal, and clinically useful prognostic factors were not found. Our results do not confirm hormonal concordance between SDC and breast carcinoma.
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Beginning in 1991-92, the Department of Medicine at The University of Alabama (UAB) changed its practices for allocating funds made available through the dean's office and for handling professional practice revenues. The specific goals of this new "plan for responsibility-center management" were--and remain--(1) to increase financial flexibility so the chair can reward productivity, strengthen existing programs, and better respond to departmental and institutional needs and opportunities; (2) to encourage the UAB tradition of responsible entrepreneurism at the levels of division directors and individual faculty; (3) to increase extramurally funded program-building at the division level; and (4) to relate the costs of practice directly to total patient care revenues. The plan's intent is to provide rewards, incentives, and recognition for the contributions of individual faculty. The author describes in detail the operation of the plan and the traditions and assumptions underlying it (e.g., the first requirement is to have good employees), and evaluates its effects, strengths, and weaknesses after three full fiscal years. He explains how the plan was introduced and implemented, documents the outstanding gains in the department's financial resources, both short- and long-term, and describes past and ongoing difficulties (for example, the effect of historic UAB decisions regarding the funding of graduate medical education, the extreme decentralization of clinic operations and patient care billing activities, and the question of how fast the shift to capitated managed care will be). He concludes that the plan appears to be a successful effort at broadly-based productivity enhancement, but that evaluation is ongoing.
BACKGROUND: In 1990 a new disease-associated antinuclear antibody was first recognized as a specific immunologic marker for a chronic form of ulcerative stomatitis (CUS). METHODS: Another case is reported herein and the subject of chronic ulcerative stomatitis with stratified epithelium-specific antinuclear antibodies (SES-ANA) is reviewed. Intraoral biopsies from this patient were submitted for microscopic examination and direct immunofluorescence. Indirect immunofluorescence studies were also performed. Serial SES-ANA titers were obtained with the patient on maintenance treatment with hydroxychloroquine. A skin biopsy of a recent lichenoid eruption was obtained and skin explants grown in the serum of this patient were studied in tissue culture with reference to SES-ANA binding and complement fixation. RESULTS: Biopsy and serum studies confirmed a diagnosis of CUS with SES-ANA in the patient reported. Skin biopsy showed lichen planus. The patient was treated with hydroxychloroquine with a favorable response. Serial SES-ANA titers did not parallel the disease activity. Among the substantive observations made from skin explants cultured in the serum of this patient was widespread fixation of C3 to the nuclei of basal cells. CONCLUSIONS: The case described herein extends the findings in CUS to include lichenoid skin lesions. Records show that at least four of 11 cases of CUS had skin lesions, whereas all had oral lesions. Stratified epithelium-specific antinuclear antibodies serve as the key marker of CUS. Skin explants grown in the serum of this CUS patient bind SES-ANA in tissue culture. Sections of explants fix complement. Titers of SES-ANA have been reported to parallel disease activity in one case, but not in the present case. Thus, there appears to be case-to-case variation. The treatment of choice for CUS is hydroxychloroquine.
The interneuronal network that produces local bending in the leech is distributed, in the sense that most of the interneurons involved are activated in all forms of local bending, even those in which their outputs would produce inappropriate movements. Such networks have been found to control a number of different behaviors in a variety of animals. This article reviews three issues: the physiological and modeling observations that led to the conclusion that local bending in leeches is controlled by a distributed system; what distributed processing means for this and other behaviors; and why the leech interneuronal network may have evolved to be distributed in the first place.
Considerable progress has been made in the development of defined mixtures of proteins or peptides with phospholipids which mimic the activity of natural pulmonary surfactants. Several of these biomimetic surfactants are active in animal models and clinical syndromes of surfactant deficiency. This review summarizes the structure and composition of natural surfactants and the development of defined mixtures of peptides and lipids that may be useful in the treatment of respiratory distress.
The author defines integrated health care delivery systems and comments that there are few such systems now but many in various stages of development. The size of such a system can be described in terms of the number of patients it serves, including their health status and utilization of care, the geographic configuration of the served area, the number of physicians, and the scope and extent of the facilities network. There are a variety of factors that influence a system's size; the author concentrates on the factors that an academic medical center must consider when formulating system-size goals. He discusses (1) the influence of how the institution structures itself to survive; (2) the effects of technology, innovation, and health care costs on the size and organization of these systems; and (3) the effects of the specific characteristics of the institutions' missions of education, research, and patient care. Real numbers describing integrated systems are presented as they relate to three possible institutional goals: economic viability, academic viability, and academic leadership. The author explains why academic medical centers should not try to be only tertiary or quaternary care providers for other integrated health care delivery systems, but at the same time emphasizes that there is no easy or inexpensive way for centers to develop their own systems. Alternative structures for integrated systems are discussed, such as "disease management systems" being developed by the pharmaceutical industry, an "end-to-end linkage" approach, and various ideas to include "captive markets," such as prisoners, university students, and members of communities for the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)
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BACKGROUND: Clinically significant hemorrhage from secondary port sites at laparoscopy is an uncommon but serious complication and can go unrecognized intraoperatively. CASES: A 28-year-old woman undergoing operative laparoscopy sustained abdominal wall vessel injury and required a blood transfusion. A second patient received the same injury but, when the author's technique was used, had minimal blood loss and a benign postoperative course. With this technique, a blunt instrument is placed through the sheath and into the peritoneal cavity before any secondary port is removed. The sheath is withdrawn, only the probe is kept in the abdomen, and then hemorrhage usually becomes evident. CONCLUSION: A new technique aids the diagnosis of occult abdominal vessel injury and allows rapid recanalization of the secondary trocar sheath paths.
OBJECTIVE: Retrospectively analyze several histopathologic variables that may predict neck recurrence after neck dissection. DESIGN: From 1970 through 1980, 284 patients with pathologically confirmed metastatic squamous cell carcinoma underwent neck dissection and received no adjuvant therapy. Kaplan-Meier evaluation estimated a 74% 2-year neck recurrence-free rate. After adjusting for the standard covariates of age, gender, neck stage, and tumor grade, we also controlled for the time-dependent covariates of primary recurrence, occurrence in the side of the neck not operated on, or development of new head and neck primary disease. SETTING: A large referral-based practice. RESULTS: The number of lymph nodes involved, invasion of vascular/lymphatic space, invasion of soft tissue, and desmoplastic lymph node pattern adversely affect neck recurrence. A desmoplastic stromal pattern was associated with almost a sevenfold increased risk of neck recurrence. To our knowledge, this finding has not been reported previously. CONCLUSION: Histopathologic evaluation of metastatically involved cervical nodes can identify patients with head and neck cancer who are at high risk for recurrence.
A gene for a novel, putative cytoplasmic tyrosine kinase, TXK has been isolated from a human peripheral blood cDNA library. The complete nucleotide sequence of the cDNA indicates that it is related most closely to EMT, a tyrosine kinase of T cells and to the B-cell tyrosine kinase Btk, which is mutated in X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency disease (XID) in mouse. TXK, like BTK, is a member of the Tec sub-family of Src-type (non-receptor) tyrosine kinases. Like similar Tec sub-family members, and unlike the other Src kinases, TXK lacks both the N-terminal myristylation signal and the C-terminal regulatory tyrosine. TXK expression is detected primarily in T cells and some myeloid cell lines but not in a number of other cell types. TXK shares 60% amino acid homology with EMT and 57% with BTK over the SH3, SH2 (Src-homology) and catalytic domains but unlike BTK, EMT and tec, it lacks Gap 1 homology and steroid hormone receptor homology in the N-terminal region. Genomic clones containing TXK have been isolated and hybridize to chromosome position 4p12.