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At least 415 records · Page 23Linked to original sources
PubMed2003

Surgical treatment of extensive peripapillary choroidal neovascularization in elderly patients.

PURPOSE: To report the visual outcomes and complications of surgical removal of extensive peripapillary choroidal neovascularization (PPCNV) in elderly patients. DESIGN: Retrospective review. PARTICIPANTS: Seventeen consecutive eyes of 17 patients older than age 55 undergoing PPCNV resection. METHODS: Retrospective review of eyes undergoing surgical removal of extensive PPCNV via pars plana vitrectomy. MAIN OUTCOME MEASURES: Preoperative and postoperative Snellen visual acuity. RESULTS: The mean age of patients was 76.9 years, and the mean duration of follow-up was 29.8 months. In 6 of 17 eyes, the PPCNV was extrafoveal; in two eyes, it was juxtafoveal; and in nine eyes, it was subfoveal. The cause of CNV was idiopathic (nine eyes), age-related macular degeneration (six eyes), presumed ocular histoplasmosis syndrome (one eye), and inflammation (one eye). All eyes were ineligible for laser treatment by MPS criteria. In eyes with extrafoveal CNV, the preoperative Snellen visual acuity ranged from 20/25 to 20/300, and the final visual acuity ranged from 20/40 to 20/800. The two eyes with juxtafoveal CNV had preoperative visual acuities of 20/125 and 20/300, and both had a postoperative acuity of 20/200. Eyes with subfoveal CNV had a range of preoperative visual acuity from 20/125 to 20/800, whereas the final visual acuity ranged from 20/30 to hand motions. Four of the nine eyes with subfoveal lesions had improved visual acuity. Overall, the final visual acuity was stable or improved in six eyes and worsened in 11 eyes. CNV recurrence was noted in four eyes and required reexcision, laser photocoagulation, or both. Surgical complications included retinal detachment (two eyes), retinal hole and epiretinal membrane (one eye), cystoid macular edema (two eyes), and subsequent cataract extraction (four eyes). CONCLUSIONS: Surgical removal of extensive PPCNV in the elderly does not often yield improvement or stabilization of visual acuity. However, 6 of 17 patients had stable or improved visual acuity.

Aged↗
PubMed2006

Blood volume measurements using an integrated fiberoptic monitoring system in a porcine septic shock model.

OBJECTIVES: To compare the accuracy of an integrated fiberoptic monitoring system using transpulmonary thermo-dye dilution technique to measure blood volume (BV) with standard method using chromium-51-tagged erythrocytes in septic shock. DESIGN: Prospective blinded animal laboratory study. SETTING: University department of anesthesiology. SUBJECTS: Thirty-five anesthetized and mechanically ventilated pigs (21.4 +/- 2.2 kg) were investigated over a period of 6 hrs. INTERVENTIONS: Septic shock was induced with fecal peritonitis (0.75 g . kg per body weight autologous feces). A central venous catheter was used for injection of the indicator dyes. MEASUREMENTS AND MAIN RESULTS: BV was measured by detecting indocyanine green using a 4-Fr aortic catheter with an integrated fiberoptic and thermistor connected to a computer system for calculation of transpulmonary indicator dilution BV (BVTPID). Cr-tagged erythrocytes were used as standard method of BV measurement (BV-Cr). Hemodynamic treatment scheme was aimed at maintenance of a central venous pressure of 12 mm Hg. Data were analyzed using Bland-Altman analyses. One hundred and five data pairs of simultaneous BV measurements were yielded during hemodynamic stability with a mean BVTPID of 64.2 +/- 17.8 mL . kg. Mean BV-Cr was 83.1 +/- 17.0 mL . kg. Linear regression equation was BVTPID = 0.58 x BV-Cr + 15.8 (r = .56, p < .01). Mean bias was 18.9 mL . kg (95% confidence interval, 15.7-22.1 mL . kg), with limits of agreement of -13.9 to 51.7 mL . kg. CONCLUSIONS: Transpulmonary indicator dilution for blood volume measurement agrees moderately with standard method using Cr-tagged erythrocytes in porcine septic shock.

Animals↗
PubMed1999

Milestones in the research on tobacco mosaic virus.

Beijerinck's (1898) recognition that the cause of tobacco mosaic disease was a novel kind of pathogen became the breakthrough which eventually led to the establishment of virology as a science. Research on this agent, tobacco mosaic virus (TMV), has continued to be at the forefront of virology for the past century. After an initial phase, in which numerous biological properties of TMV were discovered, its particles were the first shown to consist of RNA and protein, and X-ray diffraction analysis of their structure was the first of a helical nucleoprotein. In the molecular biological phase of research, TMV RNA was the first plant virus genome to be sequenced completely, its genes were found to be expressed by cotranslational particle disassembly and the use of subgenomic mRNA, and the mechanism of assembly of progeny particles from their separate parts was discovered. Molecular genetical and cell biological techniques were then used to clarify the roles and modes of action of the TMV non-structural proteins: the 126 kDa and 183 kDa replicase components and the 30 kDa cell-to-cell movement protein. Three different TMV genes were found to act as avirulence genes, eliciting hypersensitive responses controlled by specific, but different, plant genes. One of these (the N gene) was the first plant gene controlling virus resistance to be isolated and sequenced. In the biotechnological sphere, TMV has found several applications: as the first source of transgene sequences conferring virus resistance, in vaccines consisting of TMV particles genetically engineered to carry foreign epitopes, and in systems for expressing foreign genes. TMV owes much of its popularity as a research mode to the great stability and high yield of its particles. Although modern methods have much decreased the need for such properties, and TMV may have a less dominant role in the future, it continues to occupy a prominent position in both fundamental and applied research.

History, 19th Century↗
PubMed1984

Characterization of Peptostreptococcus asaccharolyticus glutamate dehydrogenase purified by dye-ligand chromatography.

Glutamate dehydrogenase (L-glutamate:NAD+ oxidoreductase (deaminating); EC 1.4.1.2) has been purified from Peptostreptococcus asaccharolyticus in a single step using dye-ligand chromatography. The enzyme (GDH) was present in high yields and was stabilized in crude extracts. A subunit molecular weight of 49000 +/- 500 was determined by SDS polyacrylamide gel electrophoresis and six bands were obtained after cross-linking the subunits with dimethyl suberimidate. This bacterial GDH was predominantly NAD+-linked, but was able to utilize both NADP+ and NADPH at 4% of the rates with NAD+ and NADH, respectively. An investigation of the amino acid specificity revealed some similarities with GDH from mammalian sources and some clear differences. The values of apparent Km for the substrates ammonia, 2-oxoglutarate, NADH, NAD+ and glutamate were 18.4, 0.82, 0.066, 0.031 and 6 mM, respectively. The P. asaccharolyticus GDH was not regulated by purine nucleotides, but was subject to strong inhibition with increasing ionic strength.

Chromatography, Agarose↗
PubMed1989

Pyruvate-enhanced phosphorylation potential and inotropism in normoxic and postischemic isolated working heart. Near-complete prevention of reperfusion contractile failure.

Bioenergetic and hemodynamic consequences of cellular redox manipulations by 0.2-20 mM pyruvate were compared with those due to adrenergic stress (0.7-1.1 microM norepinephrine) using isolated working guinea-pig hearts under the conditions of normoxia, low-flow ischemia, and reperfusion. 5 mM glucose (+ 5 U/l insulin) + 5 mM lactate were the basal energy-yielding substrates. To stabilize left ventricular enddiastolic pressure, ventricular filling pressure was held at 12 cmH2O under all conditions; this preload control minimized Frank-Starling effects on ventricular inotropism. Global low-flow ischemia was induced by reducing aortic pressure to levels (20-10 cmH2O) below the coronary autoregulatory reserve. Reactants of the creatine kinase, including H+ and other key metabolites, were measured by enzymatic, HPLC, and polarographic techniques. In normoxic hearts, norepinephrine stimulations of inotropism, heart rate x pressure product, and oxygen consumption (MVO2) were associated with a fall in the cytosolic phosphorylation potential [( ATP]/[( ADP].[Pi]] as judged by the creatine kinase equilibrium. In contrast, infusion of excess pyruvate (5 mM) markedly increased [ATP]/[( ADP].[Pi]) and ventricular work output, while intracellular phosphate decreased; MVO2 remained constant under the same conditions. During reperfusion following ischemia, pyruvate effected striking and concentration-dependent increases in MVO2, phosphorylation potential, and inotropism. Pyruvate dehydrogenase flux was augmented during reperfusion hyperemia followed by near-complete recoveries of [ATP]/([ADP].[Pi]), contractile force, heart rate x pressure product, and MVO2 in the presence of 5-10 mM pyruvate. Pyruvate also attenuated ischemic adenylate degradation. Omission of glucose from the perfusion medium rendered pyruvate ineffective in postischemic hearts. Similarly, excess lactate (5-15 mM) or acetate (5 mM) failed to reenergize reperfused hearts and severe depressions of MVO2 and inotropism developed despite the presence of glucose. Apparently, subcellular redox manipulations by pyruvate dissociated stimulated mitochondrial respiration and increased inotropism from low cytosolic phosphorylation potentials. This was evidence against the extramitochondrial [ADP].[Pi]/[ATP] ratio being the primary factor in the control of mitochondrial respiration. The mechanism of pyruvate enhancement of inotropism during normoxia and reperfusion is probably multifactorial. Thermodynamic effects on subcellular [NADH]/[NAD+] ratios are coupled with a rise in the cytosolic [ATP]/[( ADP].[Pi]) ratio at constant (normoxia) or increased (reperfusion) MVO2.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetates↗
PubMed1996

6-phosphofructo-1-kinase from the lipid accumulating, non-fermentative, red yeast Rhodotorula glutinis.

6-Phosphofructo-1-kinase (PFK, EC 2.7.1.11) activity was detected in extracts of Rhodotorula glutinis grown on different nitrogen and carbon sources. The activity of PFK varied depending on the composition of the culture medium and on the state of growth. Using a carbon-limited medium containing glucose and a mixed organic/inorganic nitrogen source, maximal yield, activity and stability of PFK were found under aerobic conditions at the end of the exponential growth phase. Native Rhodotorula-PFK could be separated by polyacrylamide gel electrophoresis. Applying this method for molecular mass estimation a value of 450 +/- 90 kDa was calculated. Taking into account a molecular mass of 130 +/- 5 kDa for the subunit, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis following immunoblotting, a tetrameric structure of the native PFK is likely. Polyclonal antibodies, raised against PFK from Saccharomyces cerevisiae, were able to cross-react with Rhodotorula-PFK. Therefore, there are similarities in the primary structure of both enzymes. Fructose 2,6-bisphosphate was identified as a significant activator of Rhodotorula-PFK leading to a 10-fold activation of the enzyme: maximal activation was achieved with 5 microM fructose 2,6-bisphosphate.

Antibodies, Fungal↗
PubMed1989

Physiological and Morphological Modifications in Immobilized Gibberella fujikuroi Mycelia.

Constraints created by immobilization conditions modified the physiological behavior and morphological characteristics of Gibberella fujikuroi mycelia in comparison with their development in free-cell conditions. G. fujikuroi mycelia were immobilized in different support matrices (polyurethane, carrageenan, and alginate) and showed a variety of reactions in response to the different microenvironmental factors encountered during and after immobilization. The best support with respect to gibberellic acid yield and biocatalyst stability was found to be an alginate with a high degree of polymerization. The most visible effects of immobilization included changes in growth development, morphological appearance, metabolite production, mycelial pigmentation, mycelial viability under starvation conditions, and induction of resting forms when previously immobilized mycelia were subcultured.

Journal Article↗
PubMed1978

Plastic multiwell plates to assay avian infectious bronchitis virus in organ cultures of chicken embryo trachea.

Simple assay systems for infectivity titrations of avian infectious bronchitis virus (IBV) in chicken embryo trachea organ cultures (OC) were developed using plastic multiplate wells with one tracheal ring per well; these assays appeared to be much more satisfactory than the conventional rolled-tube method. The medium, 0.05 M HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid)-buffered Eagle minimal essential medium was not changed during observation. A medium containing 0.4% bovine serum albumin did not influence the virus yield, but did stabilize virus viability during storage. Reproducibility of results obtained in the OC system was confirmed by performing replicate titrations of the Beaudette strain with three different passage histories. The mean virus titers in the OC were lower than those in chicken embryos, depending on the IBV passage histories. The time required for ciliostasis was related not only to the concentration of virus, but also to the IBV passage history. Application of OC techniques for the constant serum-variable virus neutralization test gave low neutralization indexes with excellent reproducibility as compared with those obtained in the chicken embryo assay system. Also, the slopes of neutralization curves obtained by assays in OC were less steep than those seen in the chicken embryo system.

Animals↗
PubMed1981

A new method for the preparation of metaphase chromosomes for flow analysis.

A new method for the preparation of metaphase chromosomes for flow analysis has been evaluated. It has been shown that this method, which involves detergent lysis of metaphase cells and polyamines to stabilize the DNA, yields lower coefficients of variation and background levels in the DNA histograms than is currently obtained by hexylene glycol based methods. A conventional flow cytometer (FACS-II) has been used to resolve the human karyotype into about 14 peaks after ethidium bromide staining and excitation with a relatively low level of illumination (0.4 W at 488 nm). Flow karyotypes have also been obtained from suspension cell lines, in particular from the mouse cell line, Friend 707/B10. The only disadvantage of this method is that the chromosomes are highly condensed and therefore banding studies on sorted chromosomes may not be possible.

Animals↗
PubMed1998

Use of a cysteine proteinase from Carica candamarcensis as a protective agent during DNA extraction.

We describe the use of a plant cysteine proteinase isolated from latex of Carica candamarcensis as a protective agent during isolation of bacterial DNA following growth in culture of these cells. Between 100 to 720 units of proteinase (1 microgram = 6 units) afforded good DNA protection when incubated with various kinds of microorganisms. Agarose gel electrophoresis showed that the resulting DNA was similar in size to DNA preparations obtained by treatment with proteinase K. The viability of the resulting material was checked by PCR amplification using species-specific primers. After standing at room temperature (25 degrees C) for 35 days, the enzyme lost 10% of its initial activity. The enzyme stability and good yield of DNA suggest the use of this proteinase as an alternative to proteinase K.

Animals↗
PubMed2000

Reduced background expression and improved plasmid stability with pET vectors in BL21 (DE3).

The T7 polymerase-based pET System is one of the most powerful and widely used prokaryotic expression systems available today. Expression of even slightly toxic gene products in BL21 (DE3), however, has been problematic due to basal expression, which leads to decreased plasmid stability and variable yields following large-scale growth and induction. Use of host strains such as BL21 (DE3) pLysS provides high stringency and consistent expression but typically at the cost of reduced protein levels upon induction. The experiments presented here suggest that catabolite repression can effectively reduce basal expression of the T7 polymerase gene in BL21 (DE3), yielding tight regulation and consistency comparable to that of BL21 (DE3) pLysS. By switching to a poor carbon source for the final growth cycles, the higher expression levels typical of BL21 (DE3) can readily be obtained upon induction.

Animals↗
PubMed1995

Neurologic manifestations of Churg-Strauss syndrome.

OBJECTIVE: To determine the frequency and the types of neurologic involvement in a series of patients with Churg-Strauss syndrome (CSS). DESIGN: We reviewed the medical records of 47 consecutive patients with CSS who were examined at the Mayo Clinic between January 1974 and June 1992. MATERIAL AND METHODS: The study patients were classified into two groups: (1) those with a histopathologically confirmed diagnosis of CSS who had evidence of either vasculitis or Churg-Strauss granuloma, the presence of asthma, and peripheral eosinophilia (more than 10% eosinophils) on at least one differential leukocyte count (N = 33) and (2) those with a clinical diagnosis of CSS who had evidence of vasculitis based on either multiple mononeuropathy or necrotizing cutaneous lesions, the presence of asthma, and peripheral eosinophilia (more than 10% eosinophils) on at least one differential leukocyte count (N = 14). RESULTS: Of the 47 patients, 29 (62%) had neurologic involvement. Peripheral neuropathy was detected in 25 patients: 17 had multiple mononeuropathy, 7 had distal symmetric polyneuropathy, and 1 had an asymmetric polyneuropathy. Three patients had cerebral infarctions. Less commonly identified problems included radiculopathies, ischemic optic neuropathy, and bilateral trigeminal neuropathy. Asthma preceded the onset of neurologic involvement in all cases (mean duration, 6.7 years. Follow-up data, when available, showed that corticosteroid therapy usually yielded improvement or stabilization. CONCLUSION: Neurologic involvement is common in CSS, usually manifesting as peripheral neuropathy. In this series of patients, asthma preceded the neurologic manifestations.

Adolescent↗
PubMed2003

Pattern formation in intracortical neuronal fields.

This paper introduces a neuronal field model for both excitatory and inhibitory connections. A single integro-differential equation with delay is derived and studied at a critical point by stability analysis, which yields conditions for static periodic patterns and wave instabilities. It turns out that waves only occur below a certain threshold of the activity propagation velocity. An additional brief study exhibits increasing phase velocities of waves with decreasing slope subject to increasing activity propagation velocities, which are in accordance with experimental results. Numerical studies near and far from instability onset supplement the work.

Action Potentials↗
PubMed1992

[Estimation of insulin and glucose regulation in the dairy cow using daily profiles, simple and modified glucose tolerance test].

Insulin and glucose regulation plays a central role in regulating distribution of metabolites between udder and body tissues and, consequently, in ensuring optimum adjustment between milk yield and health stability. An experimental study was conducted into four dairy cows, between 17 weeks before and 52 weeks after calving to establish six diurnal profiles for insulin and glucose concentrations in blood plasma and undertake 18 glucose tolerance tests, nine of them simple and nine modified. The three methods used in examination provided differentiated but complementary data on the glucose-insulin system of dairy cow. Flow of metabolites in the mammary gland, in early lactation, was found to be supported by low insulin concentrations in blood plasma, reduced pancreatic response to insulinogenic stimuli, and decreased responsiveness of peripheral cells to insulin. Endocrine adaptation to catabolic metabolism had its onset as early as several weeks before calving. Alterations to insulin concentrations in blood plasma as well as to pancreatic reactivity to insulinogenic stimuli and to responsiveness of peripheral cells to insulin were found to take place at various junctures. It should be proved to use the common and modified glucose tolerance test for the description of the individual metabolic type of each single dairy cow.

Animals↗
PubMed1991

[Comparative study between conservative and surgical therapy of fibular ligament ruptures of the upper ankle joint].

From January 1985 to February 1987 361 patients with ruptured lateral ankle ligaments were treated at the Department of Trauma and reconstructive Surgery at the University Hospital of Hamburg. 225 patients were included in a retrospective study. They were divided into conservative and operative groups of treatment with subdivision of immobilized treatment (Plaster Paris short-leg-cast for 6 weeks) and functional therapy (special shoe). Clinical-radiological follow-up examinations of 49 operatively and 44 conservative treated patients were carried out 2 to 4 years after cessation of therapy. The clinical results were evaluated according to a questionnaire, X-ray and clinical controls. These results lead to the conclusion that operative treatment combined with conservative plaster cast immobilization yielded better mechanical stability than conservative-functional therapy. Best results were seen after surgical treatment, but conservative immobilization with prevailing good clinical-radiological results seems to be an alternative to operative therapy in carefully elected patients.

Ankle Injuries↗
PubMedDate not supplied

[A new method of scleroplasty in progressive myopia].

The author analyzes the results of sclera fortification carried out in 154 patients (220 eyes) with progressive myopia by the method he developed, consisting in transplantation of dry solid multilobar perforated transplant of silica-dried sclera that retained its natural configuration in the course of preservation. The method is simple, safe for the patients, since compression of vorticose veins and optic nerve is ruled out, easily tolerated, and yields a high stabilizing effect (97 percent) as evidenced by a follow-up of 1.5 do 3 years.

Adolescent↗
PubMed1978

[Modification of nucleases by soluble derivatives of polysaccharides].

Preparations of pancreatic RNAase, ribonuclease Act. rimosus and nuclease Ser. marcescens covalently bound to water-soluble derivatives of polysaccharides (m-aminobenzyl-oxymethyl ether of dextran and mannan, 4beta-oxyethylsulphonylanisol, 4beta-oxyethylsulphonylaniline, 3-Cl-2-oxypropyl ethers of dextran and dialdehydedextran) have been obtained. The yields and thermal stability of immobilized nucleases depend both upon the amount and nature of the functional groups which activate the polysaccharide. Polysaccharide aminoaryl ethers capable of binding to proteins by azocoupling present special interest in view of their utilization as modifying baskings. Regulation of effectiveness of the azocoupling reaction by means of structural changes of the diazocomponent and the reaction conditions were shown. All this allows to obtain immobilized enzymes with different physico-chemical properties.

Azo Compounds↗
PubMed1995

[Long-term results of Insall's total condylar knee prosthesis (10-to-13-year follow-up)].

We have studied 10 to 13 years postoperatively the first 105 total knee arthroplasties using the Total Condylar, a semiconstrained prosthesis with sacrifice of the cruciate ligaments, inserted between 1979 and 1983, in 99 patients (6 were bilateral). The average age of these patients was 73.5 years at the time of arthroplasty. At the time of this review, 46 patients had died (49 prostheses) and 10 were lost to follow-up. Five knees had failed (4 infections), requiring prosthesis removal in three cases. The other 38 patients (41 knees) survived: 35 were available for detailed clinical and roentgenographic evaluation, 6 knees had only a clinical, x-ray, questionnaire or telephone evaluation. To evaluate the results of these prostheses, we used 3 different rating systems the SOFCOT rating system the Hospital for Special Surgery rating system the new scoring system of the Knee Society. The results with the HSS system were excellent or good in 80% of the cases. The rate of satisfactory results, somewhat lower than those of North American studies, is probably explained by the advanced age of our patients. All these prostheses were cemented. There was no aseptic loosening at 10 to 13 years follow-up. In assessing these results we can confirm the reliability of the first model of the Insall prosthesis, in spite of a small range of sizes, and of a rudimentary ancillary, which resulted in important positioning mistakes. We can confirm that a cemented knee prosthesis with sacrifice of the cruciate ligaments is reliable at more than 10 years of follow-up. The technical advancements: larger range of component sizes metal backed tibial plates better ancillary, which permits exact and reproducible placement posterially-stabilized system should yield even better long-term results, approaching those of total hip arthroplasty.

Adult↗