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Biomedical subjects

D Greene

Publications and source records attributed to D Greene.

At least 37 records · Page 2Linked to original sources
PubMed1998

Alloplastic and microvascular restoration of the mandible: a comparison study.

The evolution of mandibular reconstruction following composite resection is advanced by improved alloplastic prosthesis and reliable microvascular free tissue transfers. A 42-case, 6-year experience is presented using both methods at the University of California, San Francisco. The advantages and complications of both are discussed. The authors conclude that the success rate for lateral defect restoration is equivalent with either technique, and that the anterior defects are more reliably reconstructed with free tissue transfer. The advantage of microvascular flaps in the anterior defect must be gauged against the physical status of the patient, disease extent, and likelihood of dental rehabilitation by interosseous fixation.

Aged↗
PubMed1998

Double-blind randomized trial of tramadol for the treatment of the pain of diabetic neuropathy.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of tramadol in treating the pain of diabetic neuropathy. BACKGROUND: The pain of diabetic neuropathy is a major cause of morbidity among these patients and treatment, as with other small-fiber neuropathies, is often unsatisfactory. Tramadol is a centrally acting analgesic for use in treating moderate to moderately severe pain. METHODS: This multicenter, outpatient, randomized, double-blind, placebo-controlled, parallel-group study consisted of a washout/screening phase, during which all analgesics were discontinued, and a 42-day double-blind treatment phase. A total of 131 patients with painful diabetic neuropathy were treated with tramadol (n=65) or placebo (n=66) tramadol, which were administered as identical capsules in divided doses four times daily. The primary efficacy analysis compared the mean pain intensity scores in the tramadol and placebo groups obtained at day 42 of the study or at the time of discontinuation. Secondary efficacy assessments were the pain relief rating scores and a quality of life evaluation based on daily activities and sleep characteristics. RESULTS: Tramadol, at an average dosage of 210 mg/day, was significantly (p < 0.001) more effective than placebo for treating the pain of diabetic neuropathy. Patients in the tramadol group scored significantly better in physical (p=0.02) and social functioning (p=0.04) ratings than patients in the placebo group. No statistically significant treatment effects on sleep were identified. The most frequently occurring adverse events with tramadol were nausea, constipation, headache, and somnolence. CONCLUSIONS: The results of this placebo-controlled trial showed that tramadol was effective and safe in treating the pain of diabetic neuropathy.

Activities of Daily Living↗
PubMed1997

Epidemiology of facial injury in blunt assault. Determinants of incidence and outcome in 802 patients.

BACKGROUND: Facial assault trauma has reached epidemic proportions. While the biomechanics of injury, methods of repair, and general demography of blunt facial trauma are well known, statistical associations between epidemiological factors, incidence, and outcome are poorly understood. OBJECTIVES: To provide a comprehensive epidemiological survey of this patient population. To assess factors determining outcome and pattern of injury. DESIGN: Retrospective review of 802 patients admitted with blunt assault facial trauma. Statistical analysis of associations between epidemiological factors, incidence, and outcome with chi 2 test, 2-tailed t test, and Fisher exact test. SETTING: Urban university and county hospital. RESULTS: Statistically significant associations are demonstrated between gender and the context of assault, incidence of armed assault, presence of fracture, and rate of intoxication at injury. Poor prognostic indicators for outcome include use of tobacco and presence of a mandible fracture. Open reduction and internal fixation were found to bear a higher complication rate only in mandible fractures. CONCLUSIONS: While choice of treatment carries a statistically significant association with outcome, social variables, including gender, tobacco use, intoxication, and low socioeconomic status, produce dramatic worsening of both injury incidence and outcome.

Adolescent↗
PubMed1997

High-intensity focused ultrasound in the treatment of benign prostatic hyperplasia.

OBJECTIVE: To assess the role of high-intensity focused ultrasound (HIFU) in the treatment of symptomatic benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: Thirteen patients (mean age 65 years, range 58-74) were treated with HIFU as part of a phase-2 clinical trial and evaluated prospectively using the International Prostate Symptom Score, uroflowmetry, and transrectal and transabdominal ultrasonography to determine prostate size and post-void residual urine volume, respectively. The results and the patients' satisfaction were assessed at regular intervals for 2 years. RESULTS: The new procedure was learned quickly and was easy to perform. Symptom scores decreased from a mean of 23 before treatment to 5 after 12 months and 7 after 2 years. There was an initial improvement in flow rates but they then declined. The size of the prostate and the post-void residual volume were both decreased after treatment. CONCLUSIONS: The treatment is safe, easy to implement and was effective in substantially reducing symptom scores in these few patients. However, we would not encourage its use as an alternative to other well established treatment modalities until it has been assessed fully in a randomized trial.

Aged↗
PubMed1997

Determination of testicular function after torsion by DNA flow cytometry of serial fine-needle aspirates.

OBJECTIVE: To determine the efficacy of DNA flow cytometric analysis of testicular percutaneous fine-needle aspirates in the assessment and follow-up of testicular function after torsion, and to determine the relationship between the duration of torsion and testicular injury. MATERIALS AND METHODS: Three groups of 15 adult rats underwent a 720 degrees torsion, with fixation of the mesorchial ligament, for 1, 3 or 5 h. Bilateral aspirations, performed 7, 21 and 35 days after torsion were examined by flow cytometry. Testes were harvested and evaluated histologically using Johnsen's scoring. RESULTS: Irreversible testicular injury occurred in all three groups of rats, with loss of function after 1 h and loss of viability after 3 and 5 h. The results from flow cytometry suggested significant contralateral testicular injury (P < 0.025) but this was not supported by the histological evaluation. There was a strong correlation between the testicular function assessed by flow cytometry and by Johnsen's scoring of histological specimens (r2 = 0.95). CONCLUSION: The assessment of testicular aspirates by flow cytometry allows testicular function to be followed after torsion in rats, and potentially in humans. Using DNA flow cytometry, the temporal course of the twisted testis in the adult rat was determined; contralateral testicular injury following the reversal of torsion could not be excluded.

Animals↗
PubMed1997

Biomechanical effects of e-PTFE implant structure on soft tissue implantation stability: a study in the porcine model.

Successful implantation of biocompatible materials depends on physical aspects of its structure. Meshed implants are stable but cannot be easily removed. Nonporous materials are easily removed, but subject to extrusion. We hypothesized that the microporous structure of expanded polytetrafluoroethylene (e-PTFE) would permit limited fibrous ingrowth into the substance of the material, and that tubular implant shape would increase tissue integration while preserving ease of removal. A two-tailed in vivo study was done comparing implant retention, strength of fixation, and removability between tubular and solid-strip e-PTFE implants. Differences in implant retention within tissues were assessed by implanting 396 implants subcutaneously in five swine for observation periods ranging from 3 weeks to 12 months. Strength of implant attachment to host soft tissues was measured at 52 sites by extraction with a tensiometer with forces both parallel and perpendicular to the implant used. Implant porosity was assessed with scanning electron micrography of tubular and solid-strip e-PTFE implants. Measurements of the force and stress tolerances of the implant-tissue interface demonstrated significantly stronger attachment in tubular than strip-shaped implants (P < 0.005). The 11 N (2.75 lb) force sustained by the tubular implant exceeded the 3.4 N (<1 lb) force for the e-PTFE strip by a statistically significant margin on two-tailed Student's t-test (P < 0.005). Even greater forces were tolerated when applied at right angles to the axis of the tubular implant, emulating tissue suspension (21 N, 5.25 lb). The forces and stresses tolerated by both e-PTFE implants far exceeded the fracture stress measured for the implants. Implant extrusion rates were significantly smaller in tubular (0.85%) than in strip-shaped (4.4%) e-PTFE implants (P < 0.05). Standard error of the mean (SEM) demonstrated lesser porosity in tubular than strip implants, suggesting lesser direct tissue attachment. Tubular e-PTFE implant structure facilitates ingrowth of soft tissue through the tube's lumen. This increases the attachment to surrounding soft tissues, increasing fixation strength, decreasing extrusion rate, but still allowing easy removal. These properties may improve clinical applications in facial implantation.

Animals↗
PubMed1997

Experience with segmental reconstruction of the radiated mandible with alloplastic prostheses.

Reconstruction of the mandible after radiation therapy and segmental resection is often complicated by wound breakdown, osteoradionecrosis, and crippling of the oral cavity. These complications make patient salvage after radiated oral carcinoma a high-risk endeavor. Although head and neck surgeons have improved the reliability of mandibular reconstruction with microvascular free tissue transfer, medical and oncologic issues may prohibit their application. This report presents 12 selected cases undergoing alloplastic reconstruction of the mandible and soft tissue reconstruction of the oral cavity. Although not as reliable as some reports of free tissue transfers, the results were reproducible and satisfactory in these cases, with time-efficient hospitalization and functional rehabilitation. Ten of 12 prosthetic reconstructions have been durable in this study population for as long as 36 months.

Aged↗
PubMed1997

Complications of injectable synthetic polymers in facial augmentation.

BACKGROUND: Injectable synthetic materials have been used for augmentation of soft tissue defects, correction of wrinkles, and augmentation of facial features such as the nasal dorsum. Success has been limited by inflammatory reactions, material migration, and the difficulty of removal should complications occur. OBJECTIVE: To evaluate complications resulting from soft tissue augmentation with injectable alloplastic materials. METHODS: Retrospective review of seven cases. Clinical history, treatment, histopathologic findings, and outcomes are assessed. RESULTS: Inflammatory reaction and tissue damage were refractory to antibiotics and steroids, and surgery was required to remove the foreign material. Histologic examination revealed giant cell foreign body reaction in all cases. CONCLUSION: Injectable synthetic polymers can produce significant complications including deformity and inflammatory tissue destruction, the control of which is complicated by the difficulty of removing the materials. Removable tissue fillers, such as e-PTFE, or natural materials such as collagen, autologous, fat, or Alloderm, should be considered instead.

Adult↗
PubMed1995

Patients' use of prevention behaviors in managing side effects related to chemotherapy.

PURPOSE/OBJECTIVES: To describe the use of prevention and early detection behaviors related to the side effects of chemotherapy. DESIGN: Cross-sectional, descriptive, and secondary analysis. SETTING: A large university hospital and university-affiliated community hospital. SAMPLE: 46 adult patients with cancer starting a cycle of IV chemotherapy who were predominantly white, married, and female. METHODS: Self-report utilizing a 17-item, self-administered prevention and early detection questionnaire called the Prevention Behaviors Questionnaire (PBQ); questionnaires were completed two days and five days after treatment. MAIN RESEARCH VARIABLE: Prevention and early detection behaviors. FINDINGS: Patients reported using an average of 8.8 prevention behaviors two days after chemotherapy and 9.2 behaviors five days after chemotherapy. "Tried to think more positively" was the most frequently used behavior. Internal consistency and test-retest correlation coefficients on the questionnaire were calculated to be 0.81 and 0.78, respectively. CONCLUSIONS: The PBQ had adequate internal consistency and test-retest reliability. Patients reported using many prevention and detection behaviors, although very little is known about the efficacy of these behaviors in reducing or preventing the side effects of chemotherapy. IMPLICATIONS FOR CLINICAL PRACTICE: This exploratory study does not have direct implications for practice but identifies an area for future research that may affect what nurses teach patients and how they assist patients to cope with treatment.

Antineoplastic Agents↗
PubMed1994

Comparison of 1-O-alkyl-, 1-O-alk-1'-enyl-, and 1-O-acyl-2-acetyl-sn-glycero-3-phosphoethanolamines and -3-phosphocholines as agonists of the platelet-activating factor family.

Four naturally occurring platelet-activating factor (PAF) analogs, 1-alk-1'-enyl-2-acetyl-sn-glycero-3-phosphocholine, 1-hexadecanoyl-2-acetyl-sn-glycero-3-phosphocholine, 1-octadecanoyl-2-acetyl-sn-glycero-3-phosphocholine, and 1-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamine, stimulated human neutrophils (PMN) to mobilize Ca2+, degranulate, and produce superoxide anion. They were, respectively, 5-, 300-, 500-, and 4000-fold weaker than PAF in each assay; inhibited PMN-binding of [3H]PAF at concentrations paralleling their biological potencies; and showed sensitivity to the inhibitory effects of PAF antagonists. PAF and the analogs, moreover, desensitized PMN responses to each other but not to leukotriene B4 and actually increased (or primed) PMN responses to N-formyl-MET-LEU-PHE. Finally, 5-hydroxyeicosatetraenoate-enhanced PMN responses to PAF and the analogs without enhancing the actions of other stimuli. It stereospecifically raised each analog's potency by as much as 100-fold and converted a fifth natural analog, 1-alk-1'-enyl-2-acetyl-sn-glycero-3-phosphoethanolamine from inactive to a weak stimulator of PMN. PAF and its analogs thus represent a structurally diverse family of cell-derived phospholipids which can activate, prime, and desensitize neutrophils by using a common, apparently PAF receptor-dependent mechanism.

Animals↗
PubMed1993

Phospholipase D hydrolysis of choline phosphoglycerides is selective for the alkyl-linked subclass of Madin-Darby canine kidney cells.

Madin-Darby canine kidney (MDCK) cells were used to study the synthesis of diglycerides from choline phospholipids (PC) in response to 12-O-tetradecanoylphorbol-13-acetate (TPA). In this system, diglyceride formation was blocked in the presence of ethanol (0.5%), and a corresponding amount of phosphatidylethanol (PEt) was formed, indicating that phospholipase D is responsible for the diglyceride production. Analysis of the subclasses of phosphatidylethanol revealed 1-O-alkyl-(alkyl), 1-O-alk-1'-enyl-(alkenyl), and 1-acyl species of PEt (38.0, 8.3, and 53.7%, respectively). The molecular species of the alkyl-PEt most closely matched the alkyl-PC. No change in the relative amounts of alkyl- versus acyl-PEt was observed with time after stimulation. Comparison of the alkyl content of PEt (38.0%) and the parent PC (15.2%) indicated a marked selectivity for the alkyl subclass of PC. A cell-free assay (Huang, C., Wykle, R. L., Daniel, L. W., and Cabot, M. C. (1992) J. Biol. Chem. 267, 16859-16865) for phospholipase D was also used to confirm the selectivity of the enzyme for alkyl-PC versus acyl-PC. The predominant molecular species of PEt contained saturated acyl or alkyl chains in position-1 and monounsaturated residues in position-2 accounting for approximately 50% of the total PEt. 1-O-Octadecyl-2-oleoyl-sn-glycerol, a representative alkyl molecular species, was synthesized and tested for its effect upon protein kinase C derived from MDCK cells. This alkyl-diglyceride (DG) neither stimulated protein kinase C nor inhibited its activation by diacylglycerol. In summary, TPA-stimulated phospholipase D is selective for the alkyl-PC subclass in MDCK cells. The alkyl-DG subsequently formed does not appear to function as a second-messenger in activating protein kinase C.

Alkylation↗
PubMed1993

Non-immune hydrops associated with congenital herpes simplex infection.

Non-immune hydrops fetalis is a rare pregnancy complication, which can be caused by a myriad of conditions. Etiologies include metabolic or chromosomal disorders, fetal structural anomalies, and fetal infections. We present a case of non-immune hydrops caused by an intra-uterine infection with Type 1 Herpes Simplex Virus. Evaluation of the fetus with non-immune hydrops should include an amniocentesis for viral culture of the amniotic fluid.

Adult↗
PubMed1992

Whistle blowers.

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Confidentiality↗
PubMed1992

Regulation of carboxypeptidase E. Effect of pH, temperature and Co2+ on kinetic parameters of substrate hydrolysis.

Carboxypeptidase E is a member of the carboxypeptidase A and B gene family, with many of the putative active-site and substrate-binding residues conserved between these enzymes. However, the pH optimum of carboxypeptidase E is substantially lower than that of carboxypeptidases A and B. To evaluate whether the difference in the pH optima of these carboxypeptidases reflects fundamental differences in the ionization behaviour of active-site residues, the influence of pH on carboxypeptidase E activity was examined. The V(max) for hydrolysis of dansyl-Phe-Ala-Arg is pH-independent between 5 and 7, but decreases at pH values below 5. The pKa for the group the protonation of which leads to the loss of activity is approximately 4.8, and the slope of the V(max.)/pH profile suggests that only a single ionizable group is involved. In contrast, Km and V(max.)/Km are dramatically influenced by pH over the range 5-7, with multiple ionizable groups detected in this pH range. The pKa of the group the protonation of which decreases the V(max.) of substrate hydrolysis is lower (4.5) for carboxypeptidase E which had been reconstituted with Co2+. The enthalpy of ionization of the group observed in the V(max.) profile for carboxypeptidase E is approx. 28.9 kJ/mol. These results are compatible with the active-site model of the homologous carboxypeptidase A: in this model the ionization of a metal-bound water molecule is responsible for the observed decrease in V(max.).

Amino Acid Sequence↗