Fluorescence labeling of flagellar membranes.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R Wright
Publications and source records attributed to R Wright.
Degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe.
Elevated levels of certain membrane proteins, including the sterol biosynthetic enzyme HMG-CoA reductase, induce proliferation of the endoplasmic reticulum. When the amounts of these proteins return to basal levels, the proliferated membranes are degraded, but the molecular details of this degradation remain unknown. We have examined the degradation of HMG-CoA reductase-induced membranes in the fission yeast, Schizosaccharomyces pombe. In this yeast, increased levels of the Saccharomyces cerevisiae HMG-CoA reductase isozyme encoded by HMG1 induced several types of membranes, including karmellae, which formed a cap of stacked membranes that partially surrounded the nucleus. When expression of HMG1 was repressed, the karmellae detached from the nucleus and formed concentric, multilayered membrane whorls that were then degraded. During the degradation process, CDCFDA-stained compartments distinct from preexisting vacuoles formed within the interior of the whorls. In addition to these compartments, particles that contained neutral lipids also formed within the whorl. As the thickness of the whorl decreased, the lipid particle became larger. When degradation was complete, only the lipid particle remained. Cycloheximide treatment did not prevent the formation of whorls. Thus, new protein synthesis was not needed for the initial stages of karmellae degradation. On the contrary, cycloheximide promoted the detachment of karmellae to form whorls, suggesting that a short lived protein may be involved in maintaining karmellae integrity. Taken together, these results demonstrate that karmellae membranes differentiated into self-degradative organelles. This process may be a common pathway by which ER membranes are turned over in cells.
Antifungal Agents↗
Oral immunization with attenuated Salmonella expressing human sperm antigen induces antibodies in serum and the reproductive tract.
Induction of immune responses in the reproductive tract will be crucial for a functional gamete antigen-based antifertility vaccine. Here we describe the construction and development of an avirulent Salmonella as an oral vaccine delivery vector to elicit sperm-specific immune responses in reproductive tract secretions. A cDNA sequence encoding the human sperm antigen SP10 was cloned on an asd+vector and expressed to a high level in an avirulent delta cya, delta crp, and delta asd vaccine strain of Salmonella typhimurium. Oral immunization of female BALB/c mice with this recombinant Salmonella elicited high-titer anti-SP10 IgG antibodies in serum and IgA antibodies in vaginal secretions. Anti-SP10 antibody titers could be increased by secondary and tertiary oral administrations of the recombinant Salmonella. Induction of sperm-specific antibodies in the reproductive tract following oral administration of a recombinant Salmonella could lead to the development of a simple, safe, efficient, and easy-to-use antifertility vaccine.
Acrosome↗
Preserving yeast colonies grown on agar plates as a dry, thin sheet.
Explore the source record for details and available documents.
Agar↗
Physician manpower reform: an analysis of the effects of the COGME Fourth Report on internal medicine residency positions. Council on Graduate Medical Education.
PURPOSE: To quantitate the impact of the recommendations contained in the Council on Graduate Medical Education (COGME) Fourth Report on the position distribution in internal medicine residency and fellowship programs and to recommend alternative position allocations for discussion. DATA SOURCES: The COGME Fourth Report, the National Study of Internal Medicine Manpower, and the American Medical Association Annual Survey of Graduate Medical Education. RESULTS: Our analysis of the COGME Fourth Report indicates that internal medicine PGY-1 positions would decrease from the 8,936 on duty in the 1992 academic year to 6,533 (-26.9%) for the class of the year 2000. Four thousand will enter generalist careers in internal medicine (approximately a 70% increase over current generalist output). The COGME Fourth Report recommendations would allocate first-year fellowship positions for 1,400 graduates of internal medicine residencies (-63.1%). Career-bound internal medicine positions will decrease from approximately 6,000 to 5,400 (-10.0%). The loss in PGY-1 positions is predominantly due to a decrease in the number of preliminary medicine positions and to individuals who switch from career-bound internal medicine positions to other disciplines after the PGY-1 or PGY-2 years. Pediatric positions would increase moderately from 2,426 available in 1993 to 2,520 (+3.9%). Pediatric subspecialty positions would decrease by 25% to 420, with 2,100 residents entering careers in general pediatrics. Family medicine PGY-1 positions would increase from the 2,657 available in 1993 to 3,400 (+28%). CONCLUSIONS: The recommendations contained in the COGME Fourth Report would substantially reduce the number, and significantly alter the current distribution, of residency positions. The output goals of 50% generalist careers are met by an increase in career-bound generalist positions in all three generalist specialties. The limitation of total positions to the goal of 110% of 1993 U.S. graduates comes predominantly through reduction of specialty/subspecialty career-bound positions. Internal medicine residency and subspecialty fellowship positions and programs would be significantly altered by these recommendations. The reductions in internal medicine occur predominantly in loss of positions not currently destined for careers in internal medicine and in subspecialty fellowship positions. These reductions are partially offset by an increase in the complement of residents who are destined for careers in general internal medicine.
Education, Medical, Graduate↗
Acetabular fractures: long-term follow-up of open reduction and internal fixation.
Eight-seven acetabular fractures in eighty-seven patients underwent open reduction and internal fixation at Vanderbilt University Hospital from 1984 to 1989. Fifty-six were treated by orthopaedic traumatologists. Fifty-six patients returned for long-term follow-up (range 24-80 months, average 43). Harris hip ratings were used to clinically grade the results. Poor results were found in 43%. Eighty-three percent of the patients with poor results had satisfactory surgical reductions with < 3 mm of residual displacement. Factors other than surgical reduction contributed significantly to the poor results. These included hip dislocation associated with the fracture, class III or IV heterotopic ossification, development of avascular necrosis, and age > 40 years. These factors in addition to adequacy of surgical reduction allow us to better counsel patients as to long-term prognosis.
Acetabulum↗
Compartment syndrome secondary to prolonged intraosseous infusion.
Intraosseous infusions are a valuable means of establishing intravascular access in pediatric emergencies. We report a case of compartment syndrome from prolonged intraosseous infusion (53 hours). We postulate that chemical irritation from medications, infections, the tenuous nature of intraosseous infusions, and the use of infusion pumps may all play a role in the development of compartment syndrome. We recommend that, when possible, intraosseous lines be used only temporarily until more permanent vascular access is established, that lines that do not flow with gravity be removed, and that drugs known to cause chemical burns be used with caution. In addition, the use of x-ray and hourly measurement of leg circumference may help to determine whether a line is still in place. Also, given the changing circumstances and technology under which intraosseous infusions are used, new prospective studies of their complications are needed.
Compartment Syndromes↗
Risk communication: how to answer tough patient questions.
Patients are asking: Can I catch AIDS in your office? Should I have my mercury fillings replaced? Are my children in danger from fluoridated water? If X-rays are so safe, why do you leave the room when you take them? Strategies for addressing these and other tough patient questions are discussed.
Communication↗
Nurses in independent practice: is society ready?
Explore the source record for details and available documents.
Attitude to Health↗
DiOC6 staining reveals organelle structure and dynamics in living yeast cells.
When present at low concentrations, the fluorescent lipophilic dye, DiOC6, stains mitochondria in living yeast cells [Pringle et al.: Methods in Cell Biol. 31:357-435, 1989; Weisman et al.: Proc. Natl. Acad. Sci. U.S.A. 87:1076-1080, 1990]. However, we found that the nuclear envelope and endoplasmic reticulum were specifically stained if the dye concentration was increased or if certain respiratory-deficient yeast strains were examined. The quality of nuclear envelope staining with DiOC6 was sufficiently sensitive to reveal alterations in the nuclear envelope known as karmellae. These membranes were previously apparent only by electron microscopy. At the high dye concentrations required to stain the nuclear envelope, wild-type cells could no longer grow on non-fermentable carbon sources. In spite of this effect on mitochondrial function, the presence of high dye concentration did not adversely affect cell viability or general growth characteristics when strains were grown under standard conditions on glucose. Consequently, time-lapse confocal microscopy was used to examine organelle dynamics in living yeast cells stained with DiOC6. These in vivo observations correlated very well with previous electron microscopic studies, including analyses of mitochondria, karmellae, and mitosis. For example, cycles of mitochondrial fusion and division, as well as the changes in nuclear shape and position that occur during mitosis, were readily imaged in time-lapse studies of living DiOC6-stained cells. This technique also revealed new aspects of nuclear disposition and interactions with other organelles. For example, the nucleus and vacuole appeared to form a structurally coupled unit that could undergo coordinated movements. Furthermore, unlike the general view that nuclear movements occur only in association with division, the nucleus/vacuole underwent dramatic migrations around the cell periphery as cells exited from stationary phase. In addition to the large migrations or rotations of the nucleus/vacuole, DiOC6 staining also revealed more subtle dynamics, including the forces of the spindle on the nuclear envelope during mitosis. This technique should have broad application in analyses of yeast cell structure and function.
Carbocyanines↗
Evaluation of a turbidimetric procedure for apolipoproteins A1 and B on the Ciba Corning 550 EXPRESS.
We evaluated a turbidimetric method for the estimation of apo A1 and apo B on the Ciba Corning 550 EXPRESS using Ciba Corning reagents. Interference due to bilirubin, hemoglobin, lipemia, triglycerides, and uremia was minimal, with apolipoproteins (apo) A1 and B results usually within +/- 4% of expected values. Within-run and day-to-day imprecision (coefficients of variation) ranged from 1.96 to 3.60% and 2.63 to 3.39% for apo A1 and 1.02 to 1.74% and 2.08 to 3.66% for apo B, respectively. Accuracy was determined by participation in the IFCC apolipoprotein standardization project in which results obtained on 50 patient samples were compared to those obtained by the reference laboratory. Apo A1 and apo B showed an average bias of +3.7% and +2.0% and correlation coefficients of 0.986 and 0.977, respectively. Results were also compared to those obtained on the Behring Turbitime system and showed a bias of +7.5% and -8.8% for apo A1 and apo B, respectively. The Ciba Corning automated method was rapid and gave good accuracy, precision, linearity, and parallelism and was relatively unaffected by raised triglyceride values.
Apolipoprotein A-I↗
Effects of argon laser light, alternate source light, and cyanoacrylate fuming on DNA typing of human bloodstains.
Restriction fragment length polymorphism (RFLP) profile results were obtained from deoxyribonucleic acid (DNA) isolated from human bloodstains that had been subjected to cyanoacrylate ester ("superglue") fuming, argon ion laser light and alternate light sources. All RFLP profile results obtained from treated samples were consistent with the DNA pattern from untreated bloodstains.
Argon↗
Use of an autoclavable bottletop dispenser to rapidly pour agar plates.
Explore the source record for details and available documents.
Culture Media↗
Reversible inhibition of albumin production by rat hepatocytes maintained on a laminin-rich gel (Engelbreth-Holm-Swarm) in response to secretory products of Kupffer cells and cytokines.
Decreased albumin synthesis by hepatocytes in liver injury is thought to occur in response to Kupffer cell-derived acute-phase cytokines. In this study we used hepatocytes maintained in a differentiated phenotype, by culture on a laminin-rich gel substratum (Engelbreth-Holm-Swarm matrix), to investigate the effects of Kupffer cell-conditioned medium and purified cytokines (interleukin-1, interleukin-6 and tumor necrosis factor-alpha) on albumin synthesis. Kupffer cell-conditioned medium caused a reversible decrease in albumin synthesis to 64.7% of control (p less than 0.01, Wilcoxon's rank sum test, n = 11) on day 2. Repeated doses caused further dose-dependent reversible responses. The same result was obtained when protease inhibitors (alpha 1-antitrypsin and alpha 2-macroglobulin) were added to Kupffer cell-conditioned medium (n = 3), thus eliminating the potential effect of matrix degradation. Pure interleukin-1, interleukin-6 and tumor necrosis factor-alpha also inhibited albumin synthesis (p less than 0.05, Wilcoxon's rank sum test, n = 5), interleukin-6 having the greatest effect. After exposure to interleukin-1 (30 U.ml-1) and tumor necrosis factor-alpha (300 U.ml-1), decreased albumin synthesis was followed by a rebound increase (n = 3). Our results support the hypothesis that reduced albumin synthesis in the acute-phase response is modulated by cytokines released from Kupffer cells. Moreover, our results suggest that hepatocytes may exhibit a compensatory increase in albumin synthesis after cytokine withdrawal. These findings may be of physiological importance in the recovery from injury and the acute-phase response in vivo.
Albumins↗
Mutation of a tyrosine localization signal in the cytosolic tail of yeast Kex2 protease disrupts Golgi retention and results in default transport to the vacuole.
Kex2 protease processes pro-alpha-factor in a late Golgi compartment in Saccharomyces cerevisiae. The first approximately 30 residues of the 115 amino acid CO2H-terminal cytosolic tail (C-tail) of the Kex2 protein (Kex2p) contain a Golgi retention signal that resembles coated-pit localization signals in mammalian cell surface receptors. Mutation of one (Tyr713) of two tyrosine residues in the C-tail or deletion of sequences adjacent to Tyr713 results in loss of normal Golgi localization. Surprisingly, loss of the Golgi retention signal resulted in transport of C-tail mutant Kex2p to the vacuole (yeast lysosome), as judged by kinetics of degradation and by indirect immunofluorescence. Analysis of the loss of Kex2 function in vivo after shutting off expression of wild-type or mutant forms proved that mutations that cause rapid vacuolar turnover do so by increasing the rate of exit of the enzyme from the pro-alpha-factor processing compartment. The most likely explanation for these results is that mutation of the Golgi retention signal in the C-tail results in transport of Kex2p to the vacuole by default. Wild-type Kex2p also was transported to the vacuole at an increased rate when overproduced, although apparently not due to saturation of a Golgi-retention mechanism. Instead, the wild-type and C-tail mutant forms of Kex2p may follow distinct paths to the vacuole.
Amino Acid Sequence↗
Discriminators of willingness to consider cadaveric kidney donation among black Americans.
Black Americans were classified as either willing or unwilling to consider serving as kidney donors according to a combination of demographic and social psychological variables. Findings indicated that, in addition to selected religious variables, willingness to consider donation was associated with gender, age, source of information about organ donation, perceived need for transplants among blacks, self-acceptance of transplant organs and perception of bias in the selection of transplant recipients. Implications of the findings for social work practice and future research are discussed.
Adolescent↗
Complementation between Sindbis viral RNAs produces infectious particles with a bipartite genome.
Sindbis virus, the type member of the alpha-viruses, is an enveloped virus containing a nonsegmented positive-strand RNA genome. We show that the nonstructural and the structural genes can function to produce infectious virus particles when they are expressed on two different RNA segments. The nonstructural genes are translated from an RNA in which the structural genes have been replaced by the chloramphenicol acetyltransferase gene [Xiong, C., Levis, R., Shen, P., Schlesinger, S., Rice, C. M. & Huang, H. V. (1989) Science 243, 1188-1191]. The structural genes are encoded in a defective-interfering RNA but are translated from a subgenomic RNA. Both segments contain the cis-acting sequences required for replication and packaging and are copackaged. This type of genome provides a model for an ancestral intermediate between alphaviruses and the multipartite positive-strand RNA viruses of plants. These different viruses show sequence similarities in their replicative proteins and are thought to have evolved from a common ancestor.
Animals↗