PubMed Health⌕ Search

Biomedical subjects

G E Dean

Publications and source records attributed to G E Dean.

At least 19 recordsLinked to original sources
PubMed1999

Quantification of axonal damage in traumatic brain injury: affinity purification and characterization of cerebrospinal fluid tau proteins.

Diffuse axonal injury is a primary feature of head trauma and is one of the most frequent causes of mortality and morbidity. Diffuse axonal injury is microscopic in nature and difficult or impossible to detect with imaging techniques. The objective of the present study was to determine whether axonal injury in head trauma patients could be quantified by measuring levels of CSF tau proteins. Tau proteins are structural microtubule binding proteins primarily localized in the axonal compartment of neurons. Monoclonal antibodies recognizing the form of tau found in the CSF of head trauma patients were developed by differential CSF hybridoma screening using CSF from head trauma and control patients. Clones positive for head trauma CSF tau proteins were used to characterize this form of tau and for ELISA development. Using the developed ELISA, CSF tau levels were elevated >1,000-fold in head trauma patients (mean, 1,519 ng/ml of CSF) when compared with patients with multiple sclerosis (mean, 0.014 ng/ml of CSF; p < 0.001), normal pressure hydrocephalus (nondetectable CSF tau), neurologic controls (mean, 0.031 ng/ml of CSF; p < 0.001), or nonneurologic controls (nondetectable CSF tau; p < 0.001). In head trauma, a relationship between clinical improvement and decreased CSF tau levels was observed. These data suggest that CSF tau levels may prove a clinically useful assay for quantifying the axonal injury associated with head trauma and monitoring efficacy of neuroprotective agents. Affinity purification of CSF tau from head trauma patients indicated a uniform cleavage of approximately 18 kDa from all six tau isoforms, reducing their apparent molecular sizes to 30-50 kDa. These cleaved forms of CSF tau consisted of the interior portion of the tau sequence, including the microtubule binding domain, as judged by cyanogen bromide digestion. Consistent with these data, CSF cleaved tau bound taxol-polymerized microtubules, indicating a functionally intact microtubule binding domain. Furthermore, epitope mapping studies suggested that CSF cleaved tau proteins consist of the interior portion of the tau sequence with cleavage at both N and C terminals.

Alzheimer Disease↗
PubMed1998

Disposable bedpads for incontinence: predicting their clinical leakage properties using laboratory tests.

A multi-centre project has been run to identify laboratory tests capable of predicting the leakage performance of disposable incontinence bedpads. Each of 95 subjects tested each of six products for a week in turn and reported whether or not they and/or their carers found the leakage performance of each product acceptable. In addition, carers noted the severity with which individual used bedpads had leaked so that, when they had been weighed, their leakage performance could be determined as a function of urine weight. These clinical data were compared with results from the 16 different laboratory tests used routinely for bedpad evaluation in three hospital laboratories. Each test was evaluated by seeing how well the data it yielded correlated with the clinical test data. No individual test was very successful at predicting the performance of bedpads when used as sole protection but a combination of an absorption capacity test and an absorption time test predicted the percentage of users/carers finding leakage performance acceptable, accurate to within +/- eight percentage points for all six test products. A different absorption capacity test proved most successful for bedpads used as back-up to body-worn products. It predicted the percentage of users/carers finding leakage performance acceptable, accurate to +/- five percentage points for all six products.

Absorption↗
PubMed1997

Identification of microtubule-associated protein tau isoforms in Alzheimer's paired helical filaments.

AD66 proteins derived from sodium dodecylsulfate (SDS) insoluble paired helical filaments (PHF) were isolated from Alzheimer's brain using a purification procedure developed previously in this laboratory, and characterized by immunologic and chemical cleavage methods. AD66 proteins were immunoreactive with antibodies that recognize the amino terminal, tubulin-binding, and carboxy terminal domains of microtubule-associated protein tau indicating the presence of the entire tau sequence in AD66 proteins. These proteins were reactive with antibody 423 that binds to PHF but not human adult tau. Immunologic and chemical cleavage studies indicated that only two of the six tau isoforms were present in these proteins. AD66 proteins were comprised of tau proteins containing only three tubulin binding domains with either a 29 amino acid insert or no amino terminal insert. For comparative purposes, SDS soluble PHF-tau (A68 proteins) was purified from Alzheimer's brains and normal adult tau purified from control brains. Antibody Alz-50 was immunoreactive with PHF-tau or normal tau regardless of alkaline phosphatase treatment while immunoreactivity was only observed with dephosphorylated AD66 proteins. A second phosphorylated epitope on AD66 proteins but not PHF-tau or normal tau proteins was demonstrated with antibody PHF9. These data suggest that AD66 proteins represent a more phosphorylated form of tau than PHF-tau or normal tau proteins. Two-dimensional gel electrophoresis demonstrated that AD66 proteins have higher apparent molecular weights and lower pI values than normal tau, differences possibly due to the greater phosphorylation observed in these proteins.

Adult↗
PubMed1997

Predicting the leakage performance of small bodyworn disposable incontinence pads using laboratory tests.

An international multi-centre project has been run to create an international standard for measuring the leakage performance of small, disposable incontinence pads for lightly incontinent women. One hundred and thirteen women tested batches of nine different incontinence pads of widely differing designs and noted the severity with which each individual used pad had leaked so that leakage performance could be determined as a function of urine weight. In addition, testers rated the overall leakage performance of each of the nine products on a five-point scale. These clinical data were compared with laboratory data from 153 different pad measurements, each of which was evaluated by seeing how well the data it yielded correlated with the clinical test data. A wetback test emerged as the clear winner. It usually predicted the clinical leakage performance of pads to an accuracy of +/- 10%. It involved applying 25 ml of 1% w/v saline to a pad and measuring how much escaped into a filter paper held against the wet pad for 1 min under a pressure of 1.5 kPa. Pads which released the least test fluid into the filter paper leaked least in the user tests. The method will be published as an ISO standard during 1997.

Absorption↗
PubMed1997

Active and passive compliance of the fetal bovine bladder.

PURPOSE: Others have shown that the fetal bovine bladder is relatively noncompliant. Previous studies on compliance of fetal bovine bladders have demonstrated that the youngest fetal bladders had lowest and the oldest fetal bladders (near full-term) had greatest compliance. Our study was designed to determine the level of participation of active tension in the compliance of fetal bladders during gestation. MATERIALS AND METHODS: Fetal bovine bladders were obtained immediately after maternal harvest and crown-to-rump length was measured to determine gestational age. The fetus was inspected for genitourinary anomalies and the bladder was immediately placed in chilled M199 media. Strips (1 x 0.5 cm.) were excised from the anterior sagittal plane of the bladder and subjected to length-tension analysis in oxygenated Tyrode's buffer at 37C. Tension was measured using a force transducer and length was increased using a micropositioner. Compliance refers to the length-tension studies performed in normal Tyrode's solution and consists of a combination of active (smooth muscle tone) and passive properties. Passive compliance refers to length-tension studies performed after inactivation of bladder smooth muscle tone. Compliance with muscle tone intact was determined by incrementally stretching the strips to twice resting length in physiological buffer and then permitting them to return to resting length. Passive compliance with muscle tone ablated was determined in the same fashion after overnight incubation in calcium-free Tyrode's buffer in the presence of 5 mM. egtazic acid and 10 mM. sodium azide. An exponential function was fit to the normalized length-tension curves, where the exponential coefficient (EC) is numerically inversely proportional to compliance. RESULTS: Passive compliance was greatest in the youngest bladders (EC = 0.5 in the first trimester) and gradually decreased with increasing fetal age (EC = 1.2 in the third trimester). Active compliance demonstrated the opposite pattern, since the younger bladders were more stiff (EC = 2.1 in the first and 1.6 in the third trimesters). CONCLUSIONS: These studies demonstrate that passive compliance is greatest in the youngest bladders and progressively decreases with gestation. However, active smooth muscle tone is greatest in the youngest bladders and decreases with gestation. Thus, high active smooth muscle tone in the youngest fetal bladders results in relatively poor compliance of the early stage fetal bladder.

Animals↗
PubMed1997

Fumarase C activity is elevated in response to iron deprivation and in mucoid, alginate-producing Pseudomonas aeruginosa: cloning and characterization of fumC and purification of native fumC.

We report the discovery of fumC, encoding a fumarase, upstream of the sodA gene, encoding manganese superoxide dismutase, in Pseudomonas aeruginosa. The fumC open reading frame, which terminates 485 bp upstream of sodA, contains 1,374 bp that encode 458 amino acids. A second 444-bp open reading frame located between fumC and sodA, called orfX, showed no homology with any genes or proteins in database searches. A fumarase activity stain revealed that P. aeruginosa possesses at least two and possibly three fumarases. Total fumarase activity was at least approximately 1.6-fold greater in mucoid, alginate-producing bacteria than in nonmucoid bacteria and decreased 84 to 95% during the first 5 h of aerobic growth, followed by a rapid rise to maximum activity in stationary phase. Bacteria exposed to the iron chelator 2,2'-dipyridyl, but not ferric chloride, demonstrated an increase in fumarase activity. Mucoid bacteria produced approximately twofold-higher levels of the siderophores pyoverdin and pyochelin than nonmucoid bacteria. Northern blot analysis revealed a transcript that included fumC, orfX, and sodA, the amount of which was increased in response to iron deprivation. A P. aeruginosa fumC mutant produced only approximately 40% the alginate of wild-type bacteria. Interestingly, a sodA mutant possessed an alginate-stable phenotype, a trait that is typically unstable in vitro. These data suggest that mucoid bacteria either are in an iron-starved state relative to nonmucoid bacteria or simply require more iron for the process of alginate biosynthesis. In addition, the iron-regulated, tricarboxylic acid cycle enzyme fumarase C is essential for optimal alginate production by P. aeruginosa.

Alginates↗
PubMed1997

An operon containing fumC and sodA encoding fumarase C and manganese superoxide dismutase is controlled by the ferric uptake regulator in Pseudomonas aeruginosa: fur mutants produce elevated alginate levels.

The activities of fumarase- and manganese-cofactored superoxide dismutase (SOD), encoded by the fumC and sodA genes in Pseudomonas aeruginosa, are elevated in mucoid, alginate-producing bacteria and in response to iron deprivation (D. J. Hassett, M. L. Howell, P. A. Sokol, M. L. Vasil, and G. E. Dean, J. Bacteriol. 179:1442-1451, 1997). In this study, a 393-bp open reading frame, fagA (Fur-associated gene), was identified immediately upstream of fumC, in an operon with orfX and sodA. Two iron boxes or Fur (ferric uptake regulatory protein) binding sites were discovered just upstream of fagA. Purified P. aeruginosa Fur caused a gel mobility shift of a PCR product containing these iron box regions. DNA footprinting analysis revealed a 37-bp region that included the Fur binding sites and was protected by Fur. Primer extension analysis and RNase protection assays revealed that the operon is composed of at least three major iron-regulated transcripts. Four mucoid fur mutants produced 1.7- to 2.6-fold-greater fumarase activity and 1.7- to 2.3-greater amounts of alginate than wild-type organisms. A strain devoid of the alternative sigma factor AlgT(U) produced elevated levels of one major transcript and fumarase C and manganase-cofactored SOD activity, suggesting that AlgT(U) may either play a role in regulating this transcript or function in some facet of iron metabolism. These data suggest that the P. aeruginosa fagA, fumC, orfX, and sodA genes reside together on a small operon that is regulated by Fur and is transcribed in response to iron limitation in mucoid, alginate-producing bacteria.

Alginates↗
PubMed1997

Active specific immunotherapy of metastatic melanoma with an antiidiotype vaccine: a phase I/II trial of I-Mel-2 plus SAF-m.

PURPOSE: To determine the toxicity and immunologic activity of an antiidiotype melanoma vaccine that consists of monoclonal antibody I-Mel-2 (MELIMMUNE-2, IDEC Pharmaceuticals, La Jolla, CA) and an immunologic adjuvant SAF-m. PATIENTS AND METHODS: Twenty-six patients with metastatic melanoma, 17 of whom had previously received chemotherapy, were given 2 mg of I-Mel-2 and either 100 micrograms (n = 6) or 250 micrograms (n = 20) of SAF-m. Antiidiotype vaccine was given intramuscularly (IM) biweekly for 4 weeks, and then bimonthly until disease progression. Human antimurine antibodies (HAMA), anti-I-Mel-2 antibodies, and specific antibody (Ab)3 against the melanoma epitope mimicked by the vaccine were titrated before treatment, biweekly from weeks 4 to 12, and every 4 to 8 weeks thereafter. Computed tomographic (CT) scans of the chest, abdomen, and pelvis and magnetic resonance imaging (MRI) of the brain were obtained before and bimonthly during treatment to evaluate responses. RESULTS: Elevated titers of human antimouse antibodies and anti-I-Mel-2 antibodies were associated with clinical antitumor effect (P = .02 and P = .05, respectively). Ab3 was absent in most patients, but was found in the best clinical responder. Fever, myalgias/arthralgias, fatigue, nausea, and headaches were the most common toxicities. Grade III myalgias/arthralgias and headaches required dose reduction of SAF-m in eight patients at the 250-microgram dose. No treatment-related death occurred. Six patients had an antitumor effect: one complete response in liver and lung, two minor responses, and three stable disease. The patient with a complete response has survived nearly 5 years. CONCLUSION: I-Mel-2 antiidiotype vaccine was safe, tolerated best at the 100-microgram dose of SAF-m, and had immunologic and clinical activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1996

Monoclonal antibody PHF-9 recognizes phosphorylated serine 404 of tau protein and labels paired helical filaments.

Paired helical filaments (PHFs) purified from alzheimer's brain consist of hyperphosphorylated microtubule-associated protein tau. In PHF, phosphorylation occurs at ser/thr tau residues. Several of these ser/thr phosphorylation sites lie immediately C-terminal to the tau tubulin binding domain. The C-terminal ser396 to thr413 tau region contains two or more phosphorylated residues and eight possible ser/thr phosphorylation sites. Immunologic studies and mass spectroscopy have identified ser396 as one of the phosphorylation sites but identification of more C-terminal phosphorylated residues has been hampered by the lack of monoclonal antibodies (Mabs) that recognize defined epitopes in this region. We have raised Mabs against PHF purified from Alzheimer's brain. One of these Mabs, PHF-9, showed phosphorylation-dependent binding to purified PHF and recognized a phosphorylated epitope in the C-terminal portion of cyanogen bromide-digested PHF. Epitope mapping studies employing synthetic tau phosphopeptides indicated that PHF-9 labeled a 13-mer tau peptide phosphorylated at ser404 but not the corresponding non-phosphorylated peptide. PHF-9 demonstrated no immunoreactivity with a synthetic peptide phosphorylated at ser396 indicating that the PHF-9 epitope is C-terminal to ser396. In conclusion, the present study describes a Mab, PHF-9, which recognizes phosphorylated ser404 of tau independently of phosphorylated ser396 and indicates that tau ser404 is phosphorylated in PHF.

Alzheimer Disease↗
PubMed1996

Resorption-cycle-dependent polarization of mRNAs for different subunits of V-ATPase in bone-resorbing osteoclasts.

Protein sorting in eukaryotic cells is mainly done by specific targeting of polypeptides. The present evidence from oocytes, neurons, and some other polarized cells suggests that protein sorting can be further facilitated by concentrating mRNAs to their corresponding subcellular areas. However, very little is known about the mechanism(s) involved in mRNA targeting, or how widespread and dynamic such mRNA sorting might be. In this study, we have used an in vitro cell culture system, where large multinucleated osteoclasts undergo continuous structural and functional changes from polarized (resorbing) to a nonpolarized (resting) stage. We demonstrate here, using a nonradioactive in situ hybridization technique and confocal microscopy, that mRNAs for several vacuolar H(+)-ATPase subunits change their localization and polarity in osteoclasts according to the resorption cycle, whereas mRNA for cytoplasmic carbonic anhydrase II is found diffusely located throughout the osteoclast during the whole resorption cycle. Antisense RNA against the 16-kDa or 60-kDa V-ATPase subunit inhibits polarization of the osteoclasts, as determined by cytoskeleton staining. Antisense RNA against carbonic anhydrase II, however, has no such effect.

Animals↗
PubMed1995

An institutional commitment to pain management.

PURPOSE: To share the development, implementation, and evaluation of a program called "An Institutional Commitment to Pain Management," which is based on the philosophy of organizational influence on pain management. METHODS: A tested pain education model was disseminated to 32 physician/nurse teams in settings throughout California, after which the 64 professionals returned to their institutions to serve as role models and catalysts to change the practice of pain management. Each team member completed a 39-item survey about knowledge and attitudes related to pain, which was developed by B.R.F. and colleagues, and also identified three goals for the implementation of course information. Precourse data also included administration of the knowledge and attitudes survey to participating physicians' and nurses' colleagues (10 physicians and 20 nurses per institution). Each team completed five chart audits using the pain audit tool (PAT), which was developed by B.R.F. and colleagues at the City of Hope National Medical Center. The PAT identifies how pain is managed currently at the institutional level. Final course evaluation 8 months after course completion included a summary of activities implemented by the teams as well as the factors that served as barriers and benefits to improve the quality of pain management. RESULTS: Two hundred seventy-two physicians and 629 nurses completed the survey about knowledge and attitudes related to pain, and 154 PATs were submitted. These results, as well as evaluation at the completion of the course, are discussed. CONCLUSION: The Institutional Commitment to Pain Management program is an evolving model that was developed to overcome barriers to pain relief by obtaining the commitment from institutions to improve the management of pain for their patients.

Adult↗
PubMed1995

Cloning and functional characterization through antisense mapping of a kappa 3-related opioid receptor.

We have identified a putative opioid receptor from mouse brain (KOR-3), belonging to the G protein-coupled receptor family, that is distinct from the previously cloned mu, delta, and kappa 1 receptors. Assignment of the clone to the opioid receptor family derives from both structural and functional studies. Its predicted amino acid sequence is highly homologous to that of the other opioid receptors, particularly in many of the transmembrane regions, where long stretches are identical to mu, delta, and kappa 1 receptors. Both cyclazocine and nalorphine inhibit cAMP accumulation in COS-7 cells stably expressing the clone. Northern analysis shows that the mRNA is present in brain but not in a number of other organs. Southern analysis suggests a single gene encoding the receptor. A highly selective monoclonal antibody directed against the native kappa 3 receptor recognizes, in Western analysis, the clone expressed in COS-7 cells. The in vitro translation product is also labeled by the antibody. Additional clones reveal the presence of several introns, including one in the second extracellular loop and another in the first transmembrane region. Antisense studies with an oligodeoxynucleotide directed against a region of the second extracellular loop reveal a selective blockade of kappa 3 analgesia in vivo that is not observed with a mismatch oligodeoxynucleotide based upon the antisense sequence. The mu, delta, and kappa 1 analgesia is unaffected by this antisense treatment. Antisense mapping of the clone downstream from the splice site in the first transmembrane region reveals that six different antisense oligodeoxynucleotides all block kappa 3 analgesia. In contrast, only one of an additional six different antisense oligodeoxynucleotides directed at regions upstream from this splice site is effective. This strong demarcation between the two regions raises the possibility of splice variants of the receptor. An additional clone reveals an insert in the 3' untranslated region. In conclusion, the antibody and antisense studies strongly associate KOR-3 with the kappa 3-opioid receptor, although it is not clear whether it is the kappa 3 receptor itself or a splice variant.

Amino Acid Sequence↗
PubMed1994

Cloning and functional expression of a tetrabenazine sensitive vesicular monoamine transporter from bovine chromaffin granules.

Using oligonucleotide primers derived from the vesicular monoamine transporters sequences, a cDNA predicted to encode the bovine chromaffin granule amine transporter has been cloned (b-VMAT2). Surprisingly, its structure is more similar to the rat brain transporter (VMAT2), than to the rat adrenal counterpart (VMAT1). Unlike rat VMAT1, bovine VMAT2 appears to be expressed both in the adrenal medulla and the brain, as judged by Northern analysis. After modification/deletion of the seven amino acids at the N-terminus of the protein it was expressed in a functional form. The order of affinity of the bovine VMAT2 transporter to substrates is: serotonin > dopamine = norepinephrine > epinephrine. Also, the recombinant bovine adrenal transporter is highly sensitive to tetrabenazine, in sharp contrast to the rat adrenal transporter. The findings indicate, therefore, a clear species variation in which structure and function of the bovine adrenal transporter resemble the rat brain protein, while its tissue distribution is distinct from both types of rat proteins. In addition, the predicted protein sequence is identical to the experimentally determined N-terminus sequence of the purified vesicular amine transporter [Stern-Bach et al. (1992) Proc. Natl. Acad. Sci. USA 89, 9730-9733].

Amino Acid Sequence↗
PubMed1994

Phase II study of low dose cyclophosphamide and intravenous interleukin-2 in metastatic renal cancer.

Thirteen patients with metastatic renal cancer were treated in a phase II trial with interleukin-2, 21.6 million IU/m2 intravenously daily for five days on two consecutive weeks, starting 3 days after the administration of low dose cyclophosphamide 350 mg/m2 intravenously. Treatment cycles were repeated every 21 days. No responses were seen (95% Confidence Interval: 0-22%). The most common toxicities were fever, fatigue, hypotension, nausea/emesis, and myalgia/arthralgia. There were 11 episodes of Grade III toxicity including Grade III hypotension in 7 patients. Because of the significant toxicity and the lack of observed response, the study was discontinued. Cyclophosphamide and interleukin-2 at the dose and schedule used in this study has considerable toxicity and is unlikely to improve on response rates previously seen with other IL-2 based regimens in metastatic renal cancer.

Adult↗
PubMed1994

Alzheimer's paired helical filaments: amyloid precursor protein epitope mapping.

Paired helical filaments (PHF) were electrophoretically purified and solubilized from Alzheimer's neurofibrillary tangles and consisted of a primary 66 kDa protein on SDS-PAGE analysis. A panel of antibodies raised against restricted regions of the beta-amyloid precursor protein (APP) were employed for epitope mapping studies of this 66 kDa PHF protein. Western blot studies revealed that C-terminal APP antibodies were immunoreactive with the 66 kDa PHF protein. Further analysis revealed that only antisera raised against peptides that include the beta/A4-amyloid region within the C-terminal portion of APP were immunoreactive with PHF proteins. These data complement previous immunocytochemical studies which indicated that C-terminal APP antibodies preferentially label PHF-containing neurofibrillary tangles in Alzheimer's brain. The present data suggest a similarity of secondary or tertiary structure between beta/A4-amyloid and PHF which accounts for the cross-reactivity of beta/A4-amyloid antibodies with PHF proteins.

Alzheimer Disease↗
PubMed1994

Preliminary results of laser tissue welding in extravesical reimplantation of the ureters.

One exciting potential use of laparoscopic technology is the extravesical reimplantation of the ureters. We have assessed the efficacy of laser-activated fibrinogen solder to close vesical muscle flaps over submucosal ureters (Lich-Gregoir technique) in a canine model. Four dogs were subjected to unilateral flap closures via a protein solder (indocyanine green and fibrinogen) applied to the bladder serosa and exposed to 808 nm. continuous wave diode laser energy. Contralateral reimplantation was performed using 4-zero vicryl muscle flap closures (controls). At 7, 14 and 28 days postoperatively, intravenous pyelograms confirmed bilateral ureteral patency. At intravesical pressures above 100 cm. H2O, there was no evidence of wound disruption in either group. Nondisrupted wound closures were sectioned and strained until ultimate breakage to determine tensile strength. At each study interval the laser-welded closures withstood greater stress than the controls. Although these data represent single tissue samples and are not amenable to statistical analysis, laser-welded closures appeared to be stronger at each study interval. In conclusion, laser-welded vesical wound closures appear at least as strong as suture closures in the canine model.

Animals↗