Cytoskeleton and ctenophore development.
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Animals↗
Biomedical subjects
P Chang
Publications and source records attributed to P Chang.
Postmastectomy reconstruction: comparative analysis of the psychosocial, functional, and cosmetic effects of transverse rectus abdominis musculocutaneous flap versus breast implant reconstruction.
Over 40,000 postmastectomy breast reconstructions are performed annually. In this study, we investigated the psychosocial, functional, and cosmetic effects of transverse rectus abdominis musculocutaneous (TRAM) flap versus breast implant reconstruction. Thirty-three women who had undergone postmastectomy breast reconstruction were contacted by telephone and agreed to participate in the study. Twenty-two women completed the self-assessment questionnaires regarding their quality of life, psychological symptoms, functional status, body image, and global satisfaction. The TRAM and implant groups contained 8 and 14 patients, respectively. The groups were well matched for age, employment status, marital status, race, religion, and severity of medical and surgical illnesses. The average follow-up was 36 months. Statistical analysis of the responses revealed that women who had undergone TRAM flap reconstruction were more satisfied with how their reconstructed breast felt to the touch (p = .01), and there was a trend toward greater satisfaction with the appearance of their reconstructed breast (p = .08). However, these same patients identified more difficulties as far as functioning at work or school, performing vigorous physical activities, participating in community or religious activities, visiting with relatives, and interacting with male friends (p < .04). There were no statistically significant differences in body image or overall satisfaction. In this small cohort study, both the TRAM flap group and the implant group were satisfied with the results of their breast reconstruction, but the TRAM flap group was more satisfied with how their breast felt and tended to be more satisfied with the cosmetic result. The TRAM flap group reported greater psychological, social, and physical impairments as a result of their reconstruction.
Adult↗
Clinical and pathological features of pediatric dermatofibrosarcoma protuberans.
Dermatofibrosarcoma protuberans (DFSP) is an uncommon malignant mesenchymal tumor characterized by local invasion and recurrence. Fewer than 50 cases have been reported in the pediatric population. We reviewed our experience in the treatment of children with DFSP to define clinical and pathological characteristics. Seven pediatric patients were included in the study (mean age, 11.7 yr). Clinically, the tumors were described as firm nodules fixed to the skin but mobile over the deep fascia, with slow, progressive growth. Diagnosis was made by excisional biopsy in 6 patients and punch biopsy in 1 patient. Six of 7 patients had positive margins after the diagnostic procedure. Pathologically, diagnosis was based on histology, with confirmation by CD34 staining. Definitive surgical therapy consisted of wide local excision (1-3 cm margins) in 5 patients and Moh's micrographic resection in 2 patients. There have been no local recurrences or distant metastases, with a mean follow-up of 15.1 months. Pathological and clinical diagnostic criteria for the pediatric population are reviewed, and treatment options are discussed.
Adolescent↗
Prospective comparison of two management strategies of central venous catheters in burn patients.
OBJECTIVE: Central venous catheters (CVCs) are associated with sepsis in burn patients. This study was undertaken to compare two strategies of CVC management in patients with major burn injuries. DESIGN: Forty-two burn patients with major burn injuries were randomly assigned to undergo site change every 48 hours of the CVC or to undergo wire guide exchange of the CVC every 48 hours at the same site. MATERIALS AND METHODS: Catheter insertion site, distance from the burn wound, cultures of catheter tips, and blood cultures were obtained from all patients in a prospective manner. MEASUREMENTS AND MAIN RESULTS: There was no difference in the incidence of CVC sepsis between the two groups studied. CVCs inserted less than 5 cm from the burn wound developed bacterial contamination at an earlier time than CVCs inserted more than 5 cm from the burn wound. CONCLUSIONS: There was no advantage to changing the CVC insertion site every 48 hours. Changing the CVC using the wire guide technique did not prevent, nor predict, CVC bacterial contamination.
Bacteria↗
Proximal white subungual onychomycosis in a kidney transplant patient.
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Adult↗
Ultracentrifugal analysis of factor VIII and von Willebrand factor in therapeutic preparations.
Plasma and therapeutic preparations of factor VIII (1 recombinant factor VIII and two monoclonally purified plasma-derived factor VIII preparations, Kogenate, and AHF-M and Monoclate, respectively) were centrifuged in a sucrose density gradient, and the fractions were analyzed for factor VIII and von Willebrand factor (vWF). The residual vWF in the monoclonally purified factor VIII preparations sediments more slowly than the vWF of plasma. In the absence of added vWF, the factor VIII in all preparations sediments more slowly than plasma factor VIII. These same preparations of factor VIII added to hemophilic plasma as a source of vWF sediment differently. The addition of either recombinant factor VIII or AHF-M results in sedimentation of the factor VIII with the plasma vFW and in a position indistinguishable from factor VIII in plasma. In contrast, when Monoclate is added to hemophilic plasma in vitro, the factor VIII sediments more slowly than the vWF of the hemophilic plasma. However, 5 min after the infusion of Monoclate into a patient with hemophilia A, the factor VIII sediments with the plasma vWF. These results indicate that the addition of recombinant factor VIII and AHF-M results in random binding to all vWF multimers of plasma, while there is little exchange between the added factor VIII in Monoclate and the plasma vWF in vitro. In contrast, when the Monoclate is infused, there is rapid binding of factor VIII to the plasma vWF.(ABSTRACT TRUNCATED AT 250 WORDS)
Antibodies, Monoclonal↗
A single-blind investigation of four auricular needle puncture configurations.
In order to identify an appropriate needle puncture control for clinical trials of acupuncture we conducted a study in which ten cocaine dependent subjects rated local and systemic effects of four auricular needle puncture configurations (a) sites commonly used for addiction; (b) sites proximate to addiction specific sites; (c) sites not specific for cocaine addiction; and (d) sites in the helix. Subjects received one treatment per day on four successive days. The addiction specific sites were rated highest on local effects; proximal sites a common control were rated highest on systemic effects. A majority of patients ranked the addiction specific sites as the most preferred treatment and the helix points as the least preferred. Results suggest that needle insertion into proximate and non-specific sites may be too active for use as controls; helix regions may be more suitable.
Acupuncture Points↗
Axillary breast tissue: clinical presentation and surgical treatment.
Aberrant breast tissue is usually present along the milk line above or below the normal breast location. Occasionally, it is found in unusual locations, such as the axilla, scapula, thigh, and labia majora. Accessory axillary breast tissue is present in approximately 2% to 6% of women. Although this finding has been reported in a variety of clinical journals, such as Radiology and Human Pathology, it has received little attention in the plastic surgery literature. Axillary breast tissue, presenting as palpable thickenings in the axilla, can undergo monthly premenstrual changes, such as tenderness and swelling, difficulty with shoulder range of motion, and irritation from clothing. These symptoms may be exacerbated and become more apparent during puberty and pregnancy. In addition, it is cosmetically unsightful, and consequently, patients often desire surgery for improvement. We present a study of 28 patients who underwent surgical removal of their axillary breast tissue. From these successful reports, we recommend that axillary breast tissue should be surgically removed.
Adult↗
Tyrosine phosphorylation of the gamma subunit of Fc gamma receptors, p72syk, and paxillin during Fc receptor-mediated phagocytosis in macrophages.
Fc receptor-mediated phagocytosis in mouse macrophages occurs by a tyrosine kinase-dependent pathway (Greenberg, S., Chang, P., and Silverstein, S.C. (1993) J. Exp. Med. 177, 529-534). To identify proteins that are phosphorylated on tyrosine residues during phagocytosis, we used anti-phosphotyrosine antibodies to perform immunoblotting and immunoprecipitation of lysates derived from Fc receptor-stimulated macrophages. Proteins of 26, 30, 35, 37, 40, 43, 47, 56, 60, 68, 83, 116, and 150 kDa displayed enhanced tyrosine phosphorylation during Fc receptor-mediated phagocytosis. Tyrosine phosphorylation of these proteins was not a consequence of actin polymerization since treatment with cytochalasin D did not alter the pattern of Fc receptor-stimulated protein tyrosine phosphorylation. The 68-kDa tyrosine phosphoprotein was identified as paxillin, a cytoskeletal-associated tyrosine kinase substrate previously identified in fibroblasts and shown to localize to focal adhesions (Turner, C.E., Glenney, J.R., and Burridge, K. (1990) J. Cell Biol. 111, 1059-1068). Paxillin colocalized with F-actin beneath nascent phagosomes. In addition to the above proteins detected by anti-phosphotyrosine immunoblotting, the gamma subunit of FcRI and III was shown to undergo tyrosine phosphorylation during Fc receptor-mediated phagocytosis. Of several candidate tyrosine kinases that may be activated during Fc receptor stimulation, p72syk, but not p125FAK, displayed enhanced tyrosine phosphorylation during Fc receptor aggregation. The coordinated tyrosine phosphorylation of the gamma subunit of macrophage Fc receptors, the tyrosine kinase syk, and the cytoskeletal-associated protein, paxillin, may be important steps in integrating signals between Fc receptors and the underlying cytoskeleton.
Actins↗
1-Deamino-8-D-arginine vasopressin (DDAVP) increases platelet membrane expression of glycoprotein Ib in patients with disorders of platelet function and after cardiopulmonary bypass.
1-deamino-8-D-Arginine vasopressin (DDAVP) shortens the bleeding time in some patients with platelet dysfunction and decreases blood loss in some cardiopulmonary bypass patients. We studied platelet membrane glycoproteins in patients with von Willebrand disease (vWD), disorders of platelet function, and in cardiopulmonary bypass patients after infusion of 0.3 microgram/kg of DDAVP. Platelets from 8 cardiopulmonary bypass patients, receiving DDAVP immediately after surgery, were compared to those of 14 patients not receiving DDAVP. We also studied 12 patients with vWD, and 8 patients with platelet dysfunction receiving DDAVP. Fixed platelets, stained with monoclonal fluorescein (FITC)-labeled antibodies directed against GPIb (CD42b antigen), GPIb/IX, GPIIb/IIIa (CD41a antigen), CD63 antigen (a platelet activation protein), and P-selectin (CD62 antigen) were studied by flow cytometry. Binding of CD42b monoclonal antibody (MoAb) and anti-GPIb/IX to platelets from both groups of bypass patients increased during the 18-20 hr after surgery, but the group receiving DDAVP showed the greater increase (P = 0.032). Platelets from patients receiving DDAVP for vWD or for platelet dysfunction, had increases in CD42b MoAb and anti-GPIb/IX binding (P < 0.01) that coincided with shortening of their bleeding time. No changes were seen in binding of other antibodies. When platelets from normal donors were incubated with DDAVP for 20 hr, there were increases in platelet surface CD42b MoAb binding, while immunogold-stained transmission electron micrographs of permeabilized platelets demonstrated decreases in cytoplasmic CD42b MoAb binding. DDAVP increases platelet membrane GPIb expression in a variety of patients and may account for improvement in hemostasis seen in some studies. Redistribution of GPIb from the cytoplasm to the membrane may account for this increased expression.
Adult↗
Characteristics of pronuclear migration in Beroe ovata.
In the large eggs (approximately 1 mm) of the ctenophore Beroe ovata, female pronuclei migrate long distances to join stationary male pronuclei in the peripheral cytoplasm that surrounds the yolky interior. We have investigated the mechanism of nuclear migration using time lapse video recording, automated image analysis, visualization of microtubules by immunofluorescence and rhodamine-tubulin injection, and electron microscopy. Female pronuclei migrated at average speeds of 0.2 microns/sec, and were found to show periodic oscillations in velocity. Alternating phases of acceleration and deceleration occurred with an average periodicity of 235 seconds covering distances of 47 microns (about 3 times the nuclear diameter). Migration velocities and velocity oscillations were similar in fertilized and unfertilized eggs; however, changes in migration direction were much more frequent in unfertilized eggs. Characteristic deformations of the pronuclear membrane and occasional rotation of the nuclear contents were observed during migration. Inhibitor studies indicated that microtubules are required for nuclear migration. In fertilized eggs the top of the nucleus was found to move through the dense layer of aligned sperm aster microtubules. The frequent changes in direction of pronuclear migration in unfertilized eggs reflect the random organization of the microtubule layer in the absence of sperm derived centrosomes. Densely packed endoplasmic reticulum was found intermeshed with sperm aster microtubules and connected extensively with the nuclear membrane during migration. Most nuclear pores were grouped in an infolding of the nuclear membrane. We suggest that in fertilized eggs the female pronucleus is transported to the minus ends of sperm aster microtubules using motor molecules attached either to the outer nuclear membrane and/or to the network of connecting ER.
Animals↗
Randomized, prospective trial of pressure-limited versus volume-controlled ventilation in severe respiratory failure.
OBJECTIVE: Volume-controlled ventilation is frequently chosen as the initial mode of ventilatory support in patients with hypoxic respiratory failure. Recent data, however, suggest that pressure-limited ventilation, using a rapidly decelerating flow delivery pattern, may produce a more desirable clinical effect through reduced peak airway pressures and increased static compliance, tissue oxygen delivery, and consumption. This study was performed to assess the feasibility and utility of early and sustained use of pressure-limited ventilation in patients with this clinical syndrome. DESIGN: Randomized, prospective trial. SETTING: Medical intensive care unit (ICU) of a university hospital. PATIENTS: The study encompassed all patients (n = 27) receiving care in a medical ICU for acute, severe hypoxic respiratory failure (PaO2/FIO2 ratio of < 150) during a 6-month period. INTERVENTIONS: Ventilatory support via either pressure-limited or volume-controlled ventilation, initiated within 24 hrs of endotracheal intubation. MEASUREMENTS: On-line monitoring of the following ten ventilatory variables at 1-min intervals for 72 hrs or until extubation or death (maximum of 43,200 data points per patient): peak airway pressure, mean airway pressure, end-tidal CO2 concentration, CO2 minute excretion, inspiratory tidal volume, expiratory tidal volume, pause pressure, end-expiratory pressure, static thoracic compliance, and inspiratory resistance. Additionally, PaO2/FIO2 values and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were recorded on a daily basis, as were significant clinical events and changes in ventilator settings. RESULTS: Although the severity of illness at study entry as determined by APACHE II score and PaO2/FIO2 was similar in patients treated with pressure-limited or volume-controlled ventilation, peak airway pressure was consistently lower in patients randomized to pressure-limited ventilation (p = .05 at 12 hrs postintubation). The use of pressure-limited ventilation also was associated with a more rapid increase in static compliance (p = .05) than that found with volume-controlled ventilation. There was a trend toward more rapid normalization of CO2 minute excretion in patients treated with pressure-limited ventilation. Pressure-limited treated patients who survived their illness and were extubated, required fewer days of mechanical ventilation than did patients randomized to volume-controlled treated ventilation (p = .05). No pneumothoraces occurred in any study patients. One volume-controlled patient developed subcutaneous emphysema. Pressure-limited ventilation was well tolerated, and sedation requirements were equivalent in the two groups. CONCLUSIONS: Pressure-limited ventilation can be used safely and is well tolerated as an initial mode of ventilatory support in patients with acute hypoxic respiratory failure. Because the early initiation of pressure-limited ventilation is associated with lower peak airway pressure and more rapid improvement in static thoracic compliance than volume-controlled ventilation, pressure-limited ventilation may have a beneficial role when used as the primary ventilatory modality in patients with this clinical condition.
Adult↗
Application of a two-step method to the vibrational rotational spectrum of diatomic molecules.
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Journal Article↗
Malignant fibrous histiocytoma of the skin.
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Aged↗
Onychomycosis in children.
BACKGROUND: Onychomycosis is the most common nail disease in adults. During recent years an increase in its frequency has been reported in children. MATERIALS AND METHODS: Children under 12 years were examined and a clinical diagnosis of onychomycosis was made (Figs. 1-4). Potassium hydroxide (KOH) preparations were made and a fungus culture was done in each case. RESULTS: Twenty-six children with onychomycosis are reported; 16 boys (61.4%) and 10 girls (38.6%). The average age was 8 years. The most frequent variety was distal subungual onychomycosis (88.5%) and the earliest sign was distal subungual hyperkeratosis. The agent most frequently isolated was Trichophyton rubrum which was found in 18 cases (69.2%). CONCLUSIONS: Onychomycosis in children is not exceptional. Attention should be given to any sign during physical examination to avoid dystrophy of the nails and also to eliminate any source of infection.
Antifungal Agents↗
A study on patterns in the average life expectancies and mortality rates of 56 nationalities in China in 1990.
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Asia↗
Loss of endothelium-dependent vasodilatation and nitric oxide release after myocardial protection with University of Wisconsin solution.
University of Wisconsin solution has proved to be a superior form of cardioplegia for cardiac transplantation, demonstrating better functional recovery than that provided by extracellular crystalloid solutions. Furthermore, experimental data have suggested a role for University of Wisconsin solution in protection of the neonatal heart during operations for congenital heart defects. However, significant concerns have been raised regarding potential endothelial injury from the high potassium concentration contained in University of Wisconsin solution that could affect its safety and thus its clinical application. Fourteen neonatal (aged 1 to 3 days) piglet hearts were harvested and supported on an isolated, blood-perfused circuit. Endothelium-dependent vasodilatation was measured by bradykinin (10(-6) mol/L) infusion and nitric oxide release was determined. Endothelium-independent vasodilatation was then induced by sodium nitroprusside (10(-6) mol/L) infusion. A 2-hour period of cold cardioplegic arrest was instituted with multidose University of Wisconsin solution (group 1, n = 7) or blood cardioplegia (group 2, n = 7). After reperfusion and stabilization, another stimulation with bradykinin and nitroprusside was carried out and nitric oxide was again measured. After 2 hours of arrest with University of Wisconsin solution, there was a near-complete loss of vasodilatation in response to bradykinin infusion; coronary blood flow reached 245% of baseline before arrest versus only 117% of baseline after arrest (p = 0.0011). This correlated with an inability of the endothelium to release nitric oxide (96 +/- 30 nmol/min before arrest versus -32 +/- 9 nmol/min after arrest, p = 0.0039. In group 2, the vasodilatory response to bradykinin was preserved after arrest and reperfusion; 265% of baseline before arrest versus 222% of baseline after arrest. These results demonstrate a loss of endothelium-dependent vasodilatation after multidose University of Wisconsin cardioplegia caused by the inability of the endothelium to release nitric oxide. In contrast, blood cardioplegia does not result in impaired endothelial function.
Adenosine↗