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Biomedical subjects

T M Johnson

Publications and source records attributed to T M Johnson.

At least 37 records · Page 2Linked to original sources
PubMed2000

The forehead flap for nasal reconstruction.

CONTEXT: Reconstruction of extensive nasal defects often represents a significant challenge owing to several unique qualities of the nose, such as complex topography, mobile free margins, and multiple nasal subunits. Furthermore, loss of internal nasal lining and/or structural skeletal support may be present following removal of extensive skin cancers. OBJECTIVE: To describe our experience with the use of forehead flap reconstruction for extensive nasal defects. DESIGN: Retrospective case series. SETTING: Academic health care hospital system. PATIENTS/INTERVENTION: One hundred forty-seven patients with extensive nasal defects repaired with a forehead flap. MAIN OUTCOME MEASURES: The functional and aesthetic results were assessed. The characteristics of defects repaired with the forehead flap and the need for lining and/or cartilage were examined. RESULTS: The forehead flap was used to repair 147 nasal defects after Mohs excision of nonmelanoma skin cancer. Full-thickness skin was lost in all cases, structural skeletal support in 68 cases (46%), and internal mucosal lining in 45 cases (31%). Our experience and surgical technique using the forehead flap are described. CONCLUSIONS: The forehead flap represents one of the best methods for repair of extensive nasal defects. Near-normal functional and cosmetic results can be achieved.

Adult↗
PubMed2000

Solitary melanoma confined to the dermal and/or subcutaneous tissue: evidence for revisiting the staging classification.

BACKGROUND: Several patients presented with a single focus of presumed cutaneous metastatic melanoma with an unknown primary tumor based on clinical and histologic staging criteria of the American Joint Committee on Cancer (AJCC). This population is classified as having stage IV disease by the current AJCC staging system, which carries a dismal prognosis (5%-18% 5-year survival). Our clinical observation was that these patients had a higher survival rate than would be expected for stage IV disease. We believe this population represents a subgroup of primary dermal- and or subcutaneously-derived melanoma that simulates cutaneous metastatic melanoma in histologic and clinical presentation but may differ in behavior. OBSERVATIONS: The database records of 1800 patients from the University of Michigan Melanoma Clinic, Ann Arbor, were retrospectively reviewed to identify the prevalence and survival for patients diagnosed with a single focus of presumed metastatic melanoma to the skin based on accepted histologic and clinical parameters. The prevalence of this population was 0.61% (11 of 1800 patients). The Kaplan-Meier 8-year survival estimate was 83% (95% confidence interval, 58%-100%). CONCLUSIONS: By AJCC convention, these cases are classified as stage IV metastatic disease. Our data suggest that these presumed metastatic tumors do not behave like stage IV metastatic disease to the skin via lymphatic or hematogenous spread from an unknown primary site; rather, they are behaving like primary tumors originating in the dermal and/or subcutaneous tissue.

Adult↗
PubMed2000

Screening for amblyogenic factors using a volunteer lay network and the MTI photoscreener. Initial results from 15,000 preschool children in a statewide effort.

PURPOSE: To describe the results from a statewide preschool vision screening program using the MTI PhotoScreener (Medical Technology and Innovations, Inc., Cedar Falls, IA). DESIGN: Cross-sectional study. PARTICIPANTS: A total of 15,059 children aged 6 to 47 months enrolled in childcare and preschool settings throughout the state of Tennessee. METHODS: Volunteers from local Lions Clubs took photoscreening photographs of children in a statewide effort. Photographs were interpreted at the Vanderbilt Ophthalmic Photography Reading Center using predetermined criteria. Children who failed the screening were referred to community ophthalmologists or optometrists who performed a comprehensive evaluation and forwarded the results to the authors. MAIN OUTCOME MEASURES: Referral rate, unreadable rate, and predictive value positive (PVP). RESULTS: During the 2 years of the screening program, 15,059 children were screened in 850 screenings. The screening referred 1013 children (6.7%), and 704 photographs (4.7%) were unreadable. Children who failed the screening had a significant abnormality (strabismus, anisometropia, high hypermetropia, high astigmatism, or high myopia) in 320 of the 531 cases where adequate follow-up results were reported. The PVP ranged from 84% when a diagnosis of strabismus was suggested by the photoscreen reading to 41% for astigmatism. Despite intense attention to follow-up, many children who failed the screening never received a formal eye examination. CONCLUSIONS: The MTI PhotoScreener can be used by volunteers to screen preschool children and can have a high PVP in organized settings, provided that meticulous attention is paid to photograph interpretation and quality control. The PVP of the MTI PhotoScreener depends on the diagnosis suggested when the photograph is read. Significant obstacles exist in obtaining care for those who fail screening.

Amblyopia↗
PubMed2000

Expression of functional recombinant scorpion beta-neurotoxin Css II in E. coli.

The gene for a beta-neurotoxin [Centruroides suffusus suffusus toxin II (Css II)] from the scorpion C. suffusus suffusus was synthesized by recursive PCR and cloned into the expression vector, pET15b. This recombinant vector was transformed into a thioredoxin mutant host bacterial cell, AD 494(DE3)pLysS, and expression was induced with isopropyl thiogalactoside (IPTG). Although the level of expression was low, the recombinant toxin was found only in the soluble fraction with no evidence for the formation of inclusion bodies as had been observed previously with other scorpion toxins. The recombinant Css II was purified by successive ion-exchange and hydrophobic interaction chromatography. Nuclear magnetic resonance (NMR) and circular dichroism (CD) spectral measurements indicate that the protein has a native structure with no indication of denatured species. The recombinant neurotoxin inhibits the uptake of [(3)H]GABA [gamma-aminobutyric acid (GABA)] in neuronal cells as effectively as natural beta-toxins.

Amino Acid Sequence↗
PubMed2000

Concepts of sliding and lifting tissue movement in flap reconstruction.

BACKGROUND: The optimal design of a skin flap requires an understanding of the concepts of tissue movement. OBJECTIVE: The purpose of this manuscript was to demonstrate concepts of sliding and lifting tissue movement for flap reconstruction. METHODS: Six similar defects located in the forehead-temple-eyebrow region were repaired using a different skin flap. RESULTS: The specific flap design for a given defect is based on the answer to three predictable events that result from tissue transfer: Where is the tension? Where are the final incision lines? Where is the redundant tissue? CONCLUSION: A mental exercise assessing all available reconstruction options should be performed for each individual patient and defect. Both patient and defect considerations need to be assessed. A thorough understanding of both anatomy and tissue movement is necessary for optimal skin flap reconstruction.

Adult↗
PubMed2000

Collagenolytic and gelatinolytic matrix metalloproteinases and their inhibitors in basal cell carcinoma of skin: comparison with normal skin.

Tissue from 54 histologically-identified basal cell carcinomas of the skin was obtained at surgery and assayed using a combination of functional and immunochemical procedures for matrix metalloproteinases (MMPs) with collagenolytic activity and for MMPs with gelatinolytic activity. Collagenolytic enzymes included MMP-1 (interstitial collagenase), MMP-8 (neutrophil collagenase) and MMP-13 (collagenase-3). Gelatinolytic enzymes included MMP-2 (72-kDa gelatinase A/type IV collagenase) and MMP-9 (92-kDa gelatinase B/type IV collagenase). Inhibitors of MMP activity including tissue inhibitor of metalloproteinases-1 and -2 (TIMP-1 and TIMP-2) were also assessed. All three collagenases and both gelatinases were detected immunochemically. MMP-1 appeared to be responsible for most of the functional collagenolytic activity while gelatinolytic activity reflected both MMP-2 and MMP-9. MMP inhibitor activity was also present, and appeared, based on immunochemical procedures, to reflect the presence of TIMP-1 but not TIMP-2. As a group, tumours identified as having aggressive-growth histologic patterns were not distinguishable from basal cell carcinomas with less aggressive-growth histologic patterns. In normal skin, the same MMPs were detected by immunochemical means. However, only low to undetectable levels of collagenolytic and gelatinolytic activities were present. In contrast, MMP inhibitor activity was comparable to that seen in tumour tissue. In previous studies we have shown that exposure of normal skin to epidermal growth factor in organ culture induces MMP up-regulation and activation. This treatment concomitantly induces stromal invasion by the epithelium (Varani et al (1995) Am J Pathol 146: 210-217; Zeigler et al (1996b) Invasion Metastasis 16: 11-18). Taken together with these previous data, the present findings allow us to conclude that the same profile of MMP/MMP inhibitors that is associated with stromal invasion in the organ culture model is expressed endogenously in basal cell carcinomas of skin.

Blotting, Western↗
PubMed2000

Nasal reconstruction utilizing a muscle hinge flap with overlying full-thickness skin graft.

BACKGROUND: Deep nasal defects of the dorsum, sidewall, and ala can be challenging to repair. OBJECTIVE: The article describes our experience with a muscle hinge transposition flap with overlying local full-thickness skin grafting for repair of deep nasal defects in a single-stage procedure. METHODS: A muscle hinge transposition flap with overlying local full-thickness skin grafting was used immediately after Mohs micrographic surgery to repair 12 deep nasal defects of the dorsum, sidewall, alar lobule, and supratip. RESULTS: No cases of infection, flap, or graft necrosis occurred in our series. Cosmetic and functional outcomes were judged from good to excellent by patient and surgeon. To enhance the cosmetic outcome, 5 patients underwent spot dermabrasion within 2 months of repair. CONCLUSION: For properly selected small to medium-sized deep nasal defects (1-2 cm) that lack a sufficiently loose adjacent tissue reservoir for a single-stage local flap, a muscle hinge transposition flap with local full-thickness skin grafting can provide consistently satisfying aesthetic and functional results.

Basal Cell Carcinoma↗
PubMed2000

Self-care practices used by older men and women to manage urinary incontinence: results from the national follow-up survey on self-care and aging.

OBJECTIVES: To estimate the extent to which self-care practices are employed by older adults with urinary incontinence (UI); to determine how demographic and functional status measures are associated with self-care practice use; and to explore the relationship between contacting a doctor and disposable pad use. DESIGN: A cross-sectional analysis of a national probability sample using multiple logistic regression. SETTING: Responses of subjects with UI (n = 787) from the 1993-1994 National Follow-up Survey on Self-Care and Aging, a follow-up survey of older Medicare beneficiaries living in the community within the contiguous United States drawn in 1990-1991 MEASURES: Subject responses about UI, fecal incontinence, dressing, eating, bathing, Instrumental Activities of Daily Living (IADL), Mobility Activities of Daily Living (MADL), age, gender, place of residence, race, education, proxy response to the survey, and self-reported medical conditions. RESULTS: Self-care practices used by more than 25% of respondents with UI included using disposable pads, limiting trips, and limiting fluids. Among older adults with incontinence, more women used disposable pads (44.5%; 95% CI, 36.9-52.1) and performed exercises (14.2%; 95% CI, 9.7-18.9) than did men (15.1%; 95% CI, 8.1-22.1; and 4.3%; 95% CI, 1.0-7.7, respectively). Bi-variate analysis showed respondents with severe UI or fecal incontinence reported greater use of self-care practices. In multivariate models of the three most commonly used self-care practices, measures of UI severity were not always associated independently with self-care practice use, whereas ADL measures of functional status were. Disposable pad use was positively independently associated (OR 3.36; 95% CI, 2.01-5.63) in multivariate models with contacting a doctor about incontinence, even after controlling for age, gender, demographics, and self-reported medical conditions. CONCLUSIONS: Use by older adults of self-care practices to manage urinary incontinence is predicted independently in multivariate models by measures of functional status such as dressing, eating, bathing, IADLs or MADLs, but not by all UI measures. Disposable pad users had increased odds of contacting a doctor, suggesting that self-care practices and formal medical care are not always inversely related.

Activities of Daily Living↗
PubMed2000

Light scattering from cells: the contribution of the nucleus and the effects of proliferative status.

As part of our ongoing efforts to understand the fundamental nature of light scattering from cells and tissues, we present data on elastic light scattering from isolated mammalian tumor cells and nuclei. The contribution of scattering from internal structures and in particular from the nuclei was compared to scattering from whole cells. Roughly 55% of the elastic light scattering at high-angles (> 40 degrees) comes from intracellular structures. An upper limit of 40% on the fractional contribution of nuclei to scattering from cells in tissue was determined. Using cell suspensions isolated from monolayer cultures at different stages of growth, we have also found that scattering at angles greater than about 110 degrees was correlated with the DNA content of the cells. Based on model calculations and the relative size difference of nuclei from cells in different stages of growth, we argue that this difference in scattering results from changes in the internal structures of the nucleus. This interpretation is consistent with our estimate of 0.2 micron as the mean size of the scattering centers in cells. Additionally, we find that while scattering from the nucleus accounts for a majority of internal scattering, a significant portion must result from scattering off of cytoplasmic structures such as mitochondria.

Animals↗
PubMed2000

Urinary incontinence and risk of death among community-living elderly people: results from the National Survey on Self-Care and Aging.

OBJECTIVES: The authors explored whether urinary incontinence (UI) is associated with higher mortality and, if so, whether adjustment for demographics, health, and functional status diminishes the association. METHODS: The Cox proportional hazards model was used with a nationally representative sample of community-living elderly people (N = 3,485). RESULTS: In an analysis adjusted for age, gender, education, and probability sampling design, participants with mild to moderate UI (hazard ratio [HR] = 1.51; 95% confidence interval [CI] = 1.09-2.08) and severe UI (HR = 1.54; 95% CI = 1.03-2.29) experienced a higher risk of death. Adjustment for health and functional status diminished the association of UI and risk of death (mild to moderate UI, HR = 1.20, 95% CI = 0.85-1.68; severe UI, HR = 0.91, 95% CI = 0.59-1.39). DISCUSSION: The relationship between UI and mortality in older adults can largely be understood on the basis of increased frailty in incontinent individuals.

Activities of Daily Living↗
PubMed2000

History of the development of antiemetic guidelines at Mayo Clinic Rochester.

This article describes the historic experience of the development of antiemetic guidelines for patients taking chemotherapy drugs at Mayo Clinic Rochester. The initial guidelines for the use of serotonin (5-hydroxytryptamine3) receptor antagonists for the prevention of chemotherapy-induced nausea and vomiting were developed in early 1995 and implemented in September 1995. In February 1997, the guidelines were reviewed and modified. In the spring of 1998, major changes were made based on new data from the literature and discussions with antiemetic authorities in the United States. These guidelines were implemented in July 1998. The guidelines were again reviewed and modified in December 1998. In addition, we compared costs associated with the 1997 guidelines and the December 1998 guidelines. The developed guidelines, utilizing clinically available agents, seem to provide high-quality patient care at a reasonable cost.

Antiemetics↗
PubMed1999

Effects of human cytomegalovirus immediate-early proteins on p53-mediated apoptosis in coronary artery smooth muscle cells.

BACKGROUND: Restenotic and atherosclerotic lesions often contain smooth muscle cells (SMCs), which display high rates of proliferation and apoptosis. Human cytomegalovirus (HCMV) may increase the incidence of restenosis and predispose to atherosclerosis. Although the mechanisms contributing to these processes are unclear, studies demonstrate that one of the immediate-early (IE) gene products of HCMV, IE2-84, binds to and inhibits p53 transcriptional activity. Given the role of p53 in mediating apoptosis, we studied the ability of IE2-84 to inhibit p53-dependent apoptosis in human coronary artery SMCs. METHODS AND RESULTS: Apoptosis of SMCs was induced either by use of an adenovirus vector encoding human wild-type p53 protein or by treatment with doxorubicin. HCMV IE1-72 and IE2-84, the major IE proteins of HCMV, were overexpressed separately with adenovirus vectors encoding each protein, and the effects on p53-induced apoptosis were examined by both nick end-labeling (TUNEL) assay and flow cytometry. Expression of IE2-84, but not IE1-72, protected SMCs from p53-mediated apoptosis. CONCLUSIONS: These data indicate that an HCMV IE protein antagonizes p53-mediated apoptosis, suggesting a pathway by which HCMV infection predisposes to SMC accumulation and thereby contributes to restenosis and atherosclerosis.

Apoptosis↗
PubMed1999

Urinary incontinence in the older man.

Older men experience UI less often than older women, but the disruption and bother they experience because of UI is significant. Several anatomic differences between men and women account for different pathophysiology of incontinence. In men, overflow incontinence and detrusor instability predominate; stress incontinence is seen only in cases in which men have had prostate surgery. Reported symptoms of urgency and urge incontinence may be particularly difficult to interpret clinically in men because they might indicate detrusor instability or bladder outlet obstruction causing uninhibited contractions. The medical evaluation of UI is similar for men and women; men being evaluated for UI need a postvoid residual. Noninvasive measurement of urine flow may add to the diagnostic accuracy of detecting bladder outlet obstruction, but the results may not agree with results obtained by pressure-flow studies. Prostate surgery can result in UI, and biofeedback can be an effective treatment. Near-continual leakage after prostate surgery seems to be most responsive to artificial sphincter implantation. Male nursing home patients with UI present a different challenge in that mental and physical dysfunction must be addressed. Staff-dependent interventions are the most appropriate.

Aged↗
PubMed1999

Lafora disease: diagnosis by skin biopsy.

Lafora disease is a fatal neurometabolic disorder characterized by progressive myoclonic epilepsy. Diagnosis relies upon the discovery of specific inclusion bodies in any of several organs. Dermatologists and dermatopathologists should be familiar with this condition because axillary skin biopsy is useful to diagnose this disorder. We present a case of Lafora disease diagnosed by axillary skin biopsy and review the condition's clinical, histologic, and ultrastructural features.

Adolescent↗
PubMed1999

The birhombic transposition flap for soft tissue reconstruction.

BACKGROUND: Soft tissue reconstruction requires a thorough understanding of both anatomy and tissue movement. Flaps and grafts should be considered when simpler closure methods result in excessive tension or distortion of surrounding structures. OBJECTIVE: We describe our experience with the birhombic transposition flap. METHODS: The birhombic flap was used to repair 19 surgical defects after excision of skin cancer. RESULTS: The average defect size was 3.0 x 2.4 cm with the 19 wounds located on the nose (6), forearm (5), hand (4), forehead/temple (3), and preauricular cheek (1). No cases of excessive tension, infection, or flap necrosis occurred. CONCLUSION: Conceptualization of a larger defect into multiple smaller defects may be useful to facilitate closure of each smaller defect in an easier fashion. Our series demonstrates the usefulness of this concept with the birhombic transposition flap repair.

Humans↗