Biomedical subjects
Publications and source records attributed to K L Andrews.
The care of patients at risk for amputation includes the identification of at-risk patients, appropriate follow-up and treatment, and the anticipation of possible complications. Education and long-term follow-up are vital for management of the patient at risk for amputation.
Matrix metalloproteinases are matrix degrading enzymes implicated in many biological processes, including development and inflammation. Gelatinase B (gelB; also known as MMP-9) is expressed in the kidney and is hypothesized to be involved in basement membrane remodeling and in preventing pathogenic accumulation of extracellular matrix in the kidney. Inhibition of gelB activity in metanephric organ culture disrupts branching morphogenesis of the ureteric bud, suggesting that gelB plays a role in kidney development in vivo. We studied kidneys of gelB-deficient mice to search for developmental, histological, molecular, ultrastructural, and functional defects. Surprisingly, no differences between gelB-/- and control kidneys were detected, and renal function was normal in gelB mutants. In addition, gelB-/- embryonic kidneys developed normally in organ culture. Gelatinase B-deficient mice were bred with Col4a3-/- mice, a model for Alport syndrome, to determine whether gelB influences the progression of glomerulonephritis. This is an important question, as it has been hypothesized that proteases are involved in damaging Alport glomerular basement membrane. However, the presence or absence of gelB did not affect the rate of progression of renal disease. Thus, gelB does not have a discernible role in the normal kidney and gelB is not involved in the progression of glomerulonephritis in a mouse model of Alport syndrome.
Using differential display, we have identified a novel gene, KPL1, induced in rat tracheal epithelial (RTE) cells grown under conditions which stimulate ciliogenesis. The KPL1 protein is predicted to contain a pleckstrin homology (PH) domain, which has been found in numerous signal transduction and cytoskeletal proteins. These domains are thought to function by recruiting proteins to cellular membranes, and they have been shown to bind phosphoinositols and the beta/gamma subunit of G proteins. We have cloned rat and human KPL1; the predicted protein translations are 94% identical. Alternate transcripts exist in rat and human tracheal cells that predict a protein which contains a 35-amino acid insert. KPL1 was upregulated in RTE cultures undergoing mucociliary but not squamous differentiation; and in cultures undergoing mucociliary differentiation, KPL1 expression most closely paralleled that of a marker of ciliated cell differentiation (axonemal dynein heavy chain) and not a marker of mucous cell differentiation (mucin 5AC). As a new member of the family of PH domain-containing proteins, KPL1 may have a unique role in ciliated cell differentiation or function.
Repeated doses of beta-radiation in the mouse skin model have been reported to produce carcinomas and sarcomas with equal frequency. Among sarcomas, fibrosarcomas and osteosarcomas have been the predominant reported histologies. In this report we describe the beta-radiation induction of rhabdomyosarcoma (RMS), a histology previously undescribed with tumor induction protocols using ionizing radiation in an animal model. Radiation-induced RMS is often seen as a secondary tumor following therapeutic irradiation for retinoblastoma in children. In our experiment the backs of 50 CD-1 mice were irradiated 3 times weekly for 35 weeks using a 90Sr source. The initial dose was 5.5 Gy/application, which was later reduced to 3 Gy after 15 weeks due to severe skin reactions. In all, 27 skin and subcutaneous tumors were seen and collected. Of 12 sarcomas seen, 9 had a rhabdoid histology; cell lines from 3 such tumors as well as a squamous-cell carcinoma (SCC) and a malignant fibrous histiocytoma (MFH) were established. Immunohistochemical analysis of their parent tumors showed that the rhabdoid tumors expressed desmin, which established the diagnosis of RMS. Two-dimensional gel electrophoresis and Western analysis of insoluble protein extracts confirmed that the cell lines from RMS tumors expressed desmin. A screen for molecular alterations identified a mutant p53 phenotype for RMS and MFH cell lines. These radiation-induced RMS cell lines provide a unique opportunity to study the molecular biology of this tumor in an animal model and will help provide insight into the mechanisms of radiation-induced RMS in humans.
Glutathione plays an essential role in protecting the pulmonary system from toxic insults. gamma-Glutamyl transpeptidase-related enzyme (GGT-rel) is a novel protein capable of cleaving the gamma-glutamyl peptide bond of glutathione and of converting leukotriene C4 to leukotriene D4. A rat homologue of GGT-rel was identified and was found to be highly expressed in cultures of differentiating rat tracheal epithelial (RTE) cells. The 2.6-kb cDNA predicts a 572-amino acid protein with 79% identity to human GGT-rel. GGT-rel was weakly expressed in normal trachea but was strongly induced by epidermal growth factor in cultures of RTE cells. GGT-rel was also highly expressed in lung tumors induced by inhalation of isobutyl nitrite. These results demonstrate that GGT-rel 1) is expressed in normal tracheal cells, 2) can be induced by epidermal growth factor, and 3) is elevated after chemical exposure. The induction of high levels of GGT-rel may play an important role in protecting the lung from oxidative stress or other toxic insults.
Symptomatic bladder dysfunction occurs at some time in most patients with multiple sclerosis. The relapsing-remitting course and progressive loss of mobility associated with multiple sclerosis make management of urinary urgency and incontinence difficult. Urodynamic evaluation serves as a guideline for appropriate treatment. After accurate diagnosis of bladder dysfunction, a management program is developed with use of fluid schedules, voiding techniques, neuropharmacologic manipulation, intermittent catheterization, surgical treatment, and other adjunctive measures as indicated. The goals of treatment are to protect and preserve renal function, relieve symptomatic voiding dysfunction, and avoid subsequent urinary complications. A management program should be individualized, dynamic, and monitored with periodic, systematic urologic review to maintain these goals.
This self-directed learning module highlights advances in the evaluation and management of the geriatric amputee. It is part of the chapter on rehabilitation in limb deficiency in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article discusses the impact of aging and comorbid factors on the function of the geriatric amputee. Specific clinical examples are provided to illustrate management issues. Advances that are covered include prosthetic management and modifications for the elderly.
Axonemal dyneins are molecular motors that drive the beating of cilia and flagella. We report here the identification and partial cloning of seven unique axonemal dynein heavy chains from rat tracheal epithelial (RTE) cells. Combinations of axonemal-specific and degenerate primers to conserved regions around the catalytic site of dynein heavy chains were used to obtain cDNA fragments of rat dynein heavy chains. Southern analysis indicates that these are single copy genes, with one possible exception, and Northern analysis of RNA from RTE cells shows a transcript of approximately 15 kb for each gene. Expression of these genes was restricted to tissues containing axonemes (trachea, testis, and brain). A time course analysis during ciliated cell differentiation of RTE cells in culture demonstrated that the expression of axonemal dynein heavy chains correlated with the development of ciliated cells, while cytoplasmic dynein heavy chain expression remained constant. In addition, factors that regulate the development of ciliated cells in culture regulated the expression of axonemal dynein heavy chains in a parallel fashion. These are the first mammalian dynein heavy chain genes shown to be expressed specifically in axonemal tissues. Identification of the mechanisms that regulate the cell-specific expression of these axonemal dynein heavy chains will further our understanding of the process of ciliated cell differentiation.
OBJECTIVE: To describe the causes, evaluation, and management of urinary incontinence in the elderly population. DESIGN: We reviewed pertinent articles in the medical literature and summarized the types of incontinence and contributing factors. RESULTS: Urinary incontinence is common in elderly patients and often has a major role in determining whether a person can remain independent in the community or requires nursing home placement. Urinary incontinence is not a single entity but rather several different conditions, each with specific symptoms, findings on examination, and recommended treatment. Thus, accurate classification is important for appropriate management. Because of the complexity of urinary incontinence, many physicians are uncomfortable with undertaking assessment and treatment. Hence, many patients are not asked about incontinence, and the condition remains untreated and often considered a natural consequence of the aging process. Urinary incontinence can be treated and either cured or alleviated with treatment. CONCLUSION: Elderly patients should be asked about symptoms of urinary incontinence because appropriate assessment and treatment can usually provide relief.
OBJECTIVE: To describe important aspects of pressure ulcer prevention and management, especially in elderly patients. DESIGN: We reviewed pertinent published material in the medical literature and summarized effective strategies in the overall management of the elderly population with pressure ulcers. RESULTS: Pressure ulcers are commonly encountered in geriatric patients. The development of a pressure ulcer is associated with an increased risk of death. Certain well-recognized risk factors, such as immobility and incontinence, may predispose to the development of pressure ulcers; consequently, risk factor modification is an important aspect of prevention and treatment. For existing lesions, various innovative patient support surfaces and wound care products have been developed to alleviate pressure and to facilitate wound healing. The use of a particular product should be based on the clinical setting and the limited scientific evidence available. With treatment, most pressure ulcers eventually heal. CONCLUSION: Pressure ulcers are often, but not always, preventable. The occurrence of such an ulcer signals the possible presence of chronic comorbid disease and should prompt a search for underlying risk factors in patients for whom ulcer treatment is considered appropriate.
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We have generated milligram quantities of human monoclonal antibodies (Hu-MAbs) in the ascites of pristane-primed nude mice injected with human-mouse heterohybridomas. After contaminating mouse immunoglobulins were removed by affinity chromatography, an enzyme immunosorbent assay (EIA) was used to measure the concentrations of human immunoglobulins. Ten different partially purified preparations were tested. The titration curves with all 5 IgG Hu-MAbs were unusual, reaching a plateau at a very low apparent maximum concentration of antibody. In contrast, the EIA yielded more usual titration curves and thus apparently more reliable estimates of the concentrations of 4 IgM and 1 IgA monoclonal antibodies. An analogous EIA for the quantitation of mouse IgG monoclonal antibodies also gave accurate estimates. To understand the nature of the discrepancy with human IgG, 5 Hu-MAbs of the 3 classes (2 IgG, 2 pentameric IgM and 1 IgA) were purified to homogeneity for a more detailed analysis. The inability to quantitate the human IgG monoclonal antibodies by EIA was not due to defective molecules, as shown by SDS polyacrylamide gel electrophoresis. The human IgG monoclonal antibodies were found to consist of intact heavy and light chains, as were the IgM and IgA antibodies. The possibility that the human IgG monoclonal antibodies differed antigenically from polyclonal IgG was explored by comparing the concentrations by EIA with the protein concentrations determined by absorbance at 280 nm. This analysis permitted a comparison of the detectability of antigenic determinants on Hu-MAbs with those on polyclonal Ig with goat antibodies to Ig or Ig subclass. The IgG monoclonal antibodies differed from polyclonal IgG in both their heavy and light chains. Goat antiserum monospecific for the gamma chain in fact underestimated the concentration by as much as one hundred-fold. IgM and IgA monoclonal antibodies were less antigenically distinct from their polyclonal counterparts even though their light chains were also underestimated, because goat monospecific antibodies were more efficient at recognizing their heavy chains. The molecular basis for the observed difference in antigenicity is not yet known. These findings have important implications for the analysis of the binding of IgG Hu-MAbs. A direct binding assay with the label directly conjugated to the Hu-MAb should be used in preference to an indirect assay with a labeled detecting antibody to maximize the sensitivity of the assay. The altered antigenicity of IgG Hu-MAbs may also imply decreased immunogenicity when they are given in vivo as carriers for radionuclides or cytotoxic antitumor materials.
Primary monolayer cultures of human B cells established using collagenase digestion, assume a characteristic epithelial morphology which is ideal for indirect immunofluorescence studies. Using double label indirect immunofluorescence, it was possible to identify an extensive cytoplasmic microtubule complex and numerous insulin antigen positive granules within the human B cells. The microtubules are discrete rod-like structures which terminate at, or near, the plasma membrane and are observed sometimes in close association with insulin antigen positive granules. This culture system is well-suited for studying the role of the microtubules in human B cell function.
Many studies have tested the insulin absorption rate and mechanical reliability of jet injectors. However, no published papers have dealt exclusively with patient preference for this method of administering insulin over a period of years. This paper reports the results of a survey done to determine if use of a jet injector for delivering insulin has an effect on acceptance of and adherence to a regimen of multiple doses of insulin. Over the past 15 years, the authors have instructed approximately 70 patients to use various jet injectors. A questionnaire was developed and sent to 75 patients. Of these, 42 completed and returned the questionnaire. Survey results indicate that even though some problems with the injectors were identified, 70% of those responding still preferred to take insulin by jet injector.