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PubMed2004

Colonoscopy in patients 80 years of age and older is safe, with high success rate and diagnostic yield.

BACKGROUND: Colonoscopy is the standard investigation for colonic disease, but clinicians often are reluctant to refer elderly patients for colonoscopy because of a perception of higher risk and a high rate of incomplete examinations. METHODS: Data were prospectively collected on 924 consecutive colonoscopies performed over a 31-month period. Comparisons were made between two groups: patients 80 years of age or older (Group O) and patients less than 80 years of age (Group Y). Data were collected on sedation, crude and adjusted total colonoscopy rates, ileoscopy rate, anus to cecum time, total procedure time, diagnostic yield, and complications. Appropriate exclusions were made to calculate procedure success rates and time. RESULTS: Patients in Group O (n=110) received significantly less sedative medication compared with Group Y (n=814) (median dosage for midazolam, 1 mg vs. 2.5 mg; median dosage for meperidine, 12.5 vs. 25 mg; p < 0.0001). The adjusted total colonoscopy rate was 97% and 99.2% for Group O and Group Y (not significant), respectively. Ileoscopy rate was significantly lower in Group O (71.1% vs. 86.1%; p=0.0004). Median anus to cecum time was significantly longer in Group O (9.75 vs. 8.5 minutes; p=0.0182) in a single test of hypothesis; however, Bonferroni correction for multiple testing of data removes this significance. Median total procedure time also was longer in Group O (22 vs. 18.5 minutes; p=0.0001). Diagnostic yield was high, and the complication rate was low for both groups. Colorectal cancer was detected in 20% patients in Group O and 7.4% in Group Y (p < 0.0001). CONCLUSIONS: Colonoscopy in patients 80 or more years of age is safe, effective, and has a high diagnostic yield. Procedure times are slightly longer, and the ileoscopy rate is lower in this age group.

Adolescent↗
PubMed1998

Push enteroscopy for obscure gastrointestinal bleeding yields a high incidence of proximal lesions within reach of a standard endoscope.

BACKGROUND: The use of push enteroscopy to evaluate patients with obscure gastrointestinal bleeding has increased in recent years, and diagnostic yield has been reported to be 50% to 65%. This yield may be an overestimate of accuracy, as some lesions found during enteroscopy are within reach of a standard endoscope. METHODS: Ninety-five patients underwent push enteroscopy for obscure gastrointestinal bleeding. There were 58 men and 37 women with a mean age of 67 years (range 32 to 93 years). Diagnostic yield and patient outcome were assessed. RESULTS: A suspected source of bleeding was found in 39 of 95 patients (16 of these patients had endoscopic treatment of their lesions). Proximal lesions (at or above the main duodenal papilla) accounted for 25 of 39 sources (64%), including Cameron ulcers and arteriovenous malformations of the stomach/proximal duodenum. Distal lesions accounted for 14 of 39 sources (36%) with arteriovenous malformations (n=0) being most common. Patients who underwent some form of treatment (medical, surgical, or endoscopic) because of an enteroscopic finding had a statistically better outcome than patients without a lesion (73% vs. 47%, p < 0.05). CONCLUSIONS: Push enteroscopy identified a presumed bleeding source in 41 % of patients with obscure gastrointestinal bleeding. However, 64% were within reach of a standard endoscope. Repeat standard endoscopy should be considered before push enteroscopy for obscure gastrointestinal bleeding, and during enteroscopy meticulous attention should be given to the proximal gastrointestinal tract in addition to the distal duodenum and jejunum.

Adult↗
PubMed1998

Optimization of the recovery yield and of the production rate in overloaded gradient-elution reversed-phase chromatography.

To investigate the effects of various parameters on the production rate and on the recovery yield in overloaded reversed-phase gradient-elution chromatography, band profiles of binary mixtures of phenol and o-cresol were calculated using the experimental parameters of the distribution isotherms determined by binary frontal analysis. The effects of the feed volume and of the steepness of a continuous gradient (gradient time) of methanol in aqueous-organic mobile phases on the separation were studied. If the sample feed in a solvent with weak elution strength is used, combined effects of on-column enrichment, frontal chromatography and sharpening of the later eluted bands may enhance the production rate and the recovery yield. Steep continuous gradients offer better results than isocratic elution if the feed is dissolved in water and injected into the mobile phase with a higher elution strength, because larger volumes of dilute feed can be separated with high recovery yields.

Chromatography, Liquid↗
PubMed2003

A protocol for 'enhanced pepsin digestion': a step by step method for obtaining pure antibody fragments in high yield from serum.

The digestion of ovine antiserum under acidic conditions (pH 3.5) by pepsin is highly effective at reducing all unwanted serum components to low molecular weight (< or =13 kDa) fragments while leaving the approximately 100-kDa F(ab')(2) intact. The pH is then raised to 6 to stop further digestion and the reaction mixture centrifuged or filtered to remove any insoluble contaminants. Next, unwanted low molecular weight fragments are removed by diafiltration with a 30-kDa nominal molecular weight cut-off membrane leaving an F(ab')(2) solution contaminated only with some pepsin and a small amount of the aggregated low molecular weight fragments. Material of this purity is suitable for many applications but, since all the contaminants are highly acidic, they can be easily removed by passage down an anion-exchange column to yield F(ab')(2) that is essentially free from pepsin and aggregates with a typical purity of over 96% and yields of 16-19 g/l serum. When an antivenom was processed, approximately 78% of the original serum's toxin neutralising capacity was recovered. This simple, high yield protocol for processing serum to highly purified F(ab')(2) avoids the need for an initial or any subsequent salt precipitation step and can be utilised for either bench or large scale production. If required, a mild reducing agent may be used finally to create Fab fragments.

Animals↗
PubMed2003

Optimization of RNA yield, purity and mRNA copy number by treatment of urine cell pellets with RNAlater.

BACKGROUND: We have shown that measurement of mRNA for cytotoxic attack proteins perforin and granzyme B in urinary cells is a noninvasive means of diagnosing acute rejection of human renal allografts. Urinary cell mRNA studies have yielded useful information in other patient populations such as patients with cancer. The isolation of sufficient and high quality ribonucleic acid (RNA) from urinary cells however is problematic. RNAlater, an RNA stabilization solution, has been reported to optimize RNA isolation from tumor tissues stored at room temperature and from pigment-rich ocular tissues. METHODS: We explored whether the addition of RNAlater to urine cell pellets improves RNA yield, enhances purity and facilitates measurement of low abundance mRNAs. We measured, with the use of real-time quantitative polymerase chain reaction (PCR) assay, levels of expression of a constitutively expressed gene 18S rRNA and mRNA for granzyme B and transforming growth factor-beta(1) (TGF-beta(1)) in urine specimens and renal biopsies obtained from renal allograft recipients. RESULTS: RNA yield (P<0.01, Wilcoxon signed rank test) and the A260/A280 ratio (P<0.01) were both higher with urine cell pellets treated with RNAlater prior to snap freezing compared to cell pellets that were not treated with RNAlater prior to snap freezing. Levels (copy number per 1 microg of total RNA) of 18S rRNA (P<0.02), granzyme B mRNA (P=0.002) and TGF-beta(1) (P=0.02) were all higher with treated urine cell pellets compared to untreated cell pellets. Kruskall-Wallis one way analysis of variance and pair-wise comparisons with Student-Newman-Keuls test showed that the levels of mRNA for granzyme B (P<0.05) and TGF-beta(1) (P<0.05) are significantly different between renal allograft biopsies and untreated urine cell pellets but not between the biopsy specimens and RNAlater-treated urine cell pellets. CONCLUSIONS: The addition of RNAlater to urine cell pellets improves RNA isolation from urinary cells and facilitates measurement of low abundance mRNAs.

Adolescent↗
PubMed2000

3,5,3'-Triiodothyronine administered to rat dams during lactation increases milk yield and triglyceride concentration and hastens pups growth.

It is known that lactation induces a mild hypothyroid state in rats and other mammals while thyroid hormone administration increases milk secretion in ruminants. The aim of this study was to investigate the effects of a moderate dose of 3,5,3'-triiodothyronine (T3), administered to rat dams during lactation on pups' growth and milk yield and composition. Primiparous Wistar rats with litters adjusted to 10 pups per dam received either tap water or T3 (75 microg/kg x day) in their drinking water from parturition till weaning. Food and water intake of dams and body weight of dams and pups were measured daily. In other groups of rats with similar treatments, milk yield of dams, macronutrient milk composition, and mammary arteriovenous differences for triglycerides (TG) and glucose were also determined. Dams treated with T3 ingested more food and their pups gained more weight than controls. Milk yield, milk TG concentration and glucose extraction by mammary glands were also higher in T3 treated dams. The results show that compensation of the mild hypothyroidism of the lactating rat may contribute to an increase in milk production and lipid levels, leading to an increase in growth of pups.

Animals↗
PubMed1977

The effect of x-ray induced mitotic delay on chromosome aberration yields in human lymphocytes.

The extent to which X-ray induced mitotic delay at 150 and 400 rad influences chromosome aberration yields was examined in human peripheral blood lymphocytes. The dicentric was used as a marker and aberrations yields were obtained for mixed cultures prepared from equal numbers of normal and irradiated cells. The cultures were terminated following incubation times of 36-120 h. Greater mitotic delay of the order of a few hours was observed at the higher dose. However most reduction in the number of lymphocytes arriving at metaphase by 48 h may be ascribed to interphase death or failure to transform. Analysis of the dicentric distributions which were expected to follow Poisson statistics indicated that cells containing dicentrics were delayed relative to irradiated but aberration-free cells. Cells with one dicentric moved more easily through the first cell cycle than cells containing two dicentrics. Following accidental partial body irradiation, selection in culture favouring the unirradiated lymphocytes does not distort the aberration yield sufficiently to warrant incubation times in excess of the standard 48-52 h.

Cell Survival↗
PubMed1999

What motion distributions yield global transparency and spatial segmentation?

We have examined the ability of observers to parse bimodal local-motion distributions into two global motion surfaces, either overlapping (yielding transparent motion) or spatially segregated (yielding a motion boundary). The stimuli were random dot kinematograms in which the direction of motion of each dot was drawn from one of two rectangular probability distributions. A wide range of direction distribution widths and separations was tested. The ability to discriminate the direction of motion of one of the two motion surfaces from the direction of a comparison stimulus was used as an objective test of the perception of two discrete surfaces. Performance for both transparent and spatially segregated motion was remarkably good, being only slightly inferior to that achieved with a single global motion surface. Performance was consistently better for segregated motion than for transparency. Whereas transparent motion was only perceived with direction distributions which were separated by a significant gap, segregated motion could be seen with abutting or even partially overlapping direction distributions. For transparency, the critical gap increased with the range of directions in the distribution. This result does not support models in which transparency depends on detection of a minimum size of gap defining a bimodal direction distribution. We suggest, instead, that the operations which detect bimodality are scaled (in the direction domain) with the overall range of distribution. This yields a flexible, adaptive system that determines whether a gap in the direction distribution serves as a segmentation cue or is smoothed as part of a unitary computation of global motion.

Computer Graphics↗
PubMed1977

Effect of lime-pelleting on nodulation and yield of soybean grown in acid soil.

An experiment for studying the effect of lime-pelleting of inoculated seed of soybean [Glycine max. (L.) Merr.] on nodulation, growth, and grain yield was undertaken in red sandy loam of Bangalore, having a pH of 4.0. The results indicated that inoculation alone increased significantly nodulation, plant dry weight, and grain yield. But inoculation plus lime-pelleting significantly increased the dry weight of nodules and plants, but not the grain yield. However, lime-pelleting was found to be beneficial though not essential in acid soils.

Acids↗
PubMed2001

Waste-free solid-state syntheses with quantitative yield.

Unexpected organic solid-state reactions in the gas-solid and stoichiometric solid-solid versions are highly promising new tools for solvent-free sustainable synthesis and production if they occur with 100% yield. Costly workup is obsolete, no wastes are formed and resources and energy saved. More than 500 published 100%-yield, solid-state reactions in 25 reaction types cover virtually all fields of synthetic organic chemistry. Atomic force microscopy (AFM) reveals that solid-state reactions require long-range molecular movements and are strictly and sensibly guided by the crystal packing. Three steps govern the issue: phase rebuilding, phase transformation, and crystal disintegration (detachment). If one of these fails, or if liquid phases are not avoided, the reaction will usually not run to completion. Repeated creation of fresh contacts of crystallites is essential in solid-solid reactions. New, otherwise inaccessible and highly reactive products are most easily obtained. Cooling below eutectic temperatures, but also thermal activation above room temperature, may be necessary. Liquids may be solidified by cooling or inclusion complexation. Typical single-step, multi-step and cascade reactions have been performed with 100% yield using commonly available starting materials in various fields. Upscaling to the kilogram scale has been achieved under various conditions. Further upscaling to technical size productions seems possible.

Biotechnology↗
PubMed2000

The use of PLS algorithms and quantum chemical parameters derived from PM3 hamiltonian in QSPR studies on direct photolysis quantum yields of substituted aromatic halides.

The Partial Least-Squares (PLS) method was used to further study Quantitative Structure-Property Relationship (QSPR) for photohydrolysis quantum yields of selected aromatic halides. The cluster of substituted bromobenzenes and iodobenzenes was further grouped into two clusters, substituted bromobenzenes and substituted iodobenzenes, for which QSPRs were obtained, respectively. The QSPRs obtained by PLS are more significant than those obtained in previous studies. The studies showed that only when the compounds belonging to different groups are studies separately, inherent relationships between molecular properties and their structure characteristics can be revealed. It can be generally concluded that the photohydrolysis quantum yields of the substituted aromatic halides are dependent on the overall characters of the molecules, the characters of the carbon-halogen bonds to be broken in the photolysis, and the character of the halogen atoms to be replaced in the photolysis. Electronegativity has great relevance to the photohydrolysis processes of the compounds. Substituted aromatic halides with large average molecular polarizability and molecular weight values tend to have low photolysis quantum yields.

Algorithms↗
PubMed2002

Reservoir yield assessment in a changing Scottish environment.

The application of a variety of reservoir yield estimation methods is described against the background of a review of yield in Scotland. The study is timely, both in the context of the possible effects of climate change, the institutional re-organisation of the water industry world-wide--but originating largely from the UK-and the emerging issues of sustainability and the shift from supply to demand side management. To set the paper in context, the study was undertaken just prior to the transfer of responsibility for water supply from regional councils to new water authorities in 1996, and following the quinquennial Scottish Office Environment Department's survey of water resources in 1994. A comparative review of assessment methods was undertaken in order to recommend a flexible and consistent approach for single sources, but with a view to extending this to conjunctive schemes. A case study of Loch Bradan showed that the derivation of the inflow record and definition of the catchment boundary are at least as important as the yield assessment method itself.

Conservation of Natural Resources↗
PubMed2003

The temporal and spatial variability of sediment transport and yields within the Bradford Beck catchment, West Yorkshire.

Recent EU directives have emphasised the need to understand and limit potential water quality problems within urban river systems. Under certain conditions sediments and contaminants derived from industrial and domestic waste and the urban surface may be expelled into urban rivers via the sewer and drainage system. These discharges may lead to water quality problems within urban catchments. One aspect of water quality is the suspended sediment. This can be directly detrimental to water quality by affecting the habitat for fish and other biota but it is also closely associated with pollutants, such as heavy metals, which may be adsorbed onto the sediments surface. This paper presents a comparative analysis of sediment yields for a small mixed rural/urban catchment, the Bradford Beck in West Yorkshire, over a number of precipitation events. Flow and water quality parameters were monitored at a high temporal resolution at strategic sites within the urban watercourse over a 2-year period. Rainfall was measured at six locations within the catchment. Analysis of discrete rainfall events allowed an understanding of the temporal and spatial variability of sediment transport within the catchment to be developed. The results demonstrated that for individual storms the sediment yields from the urban sub-catchment were generally higher than those from the rural system although the annual yields were comparable. Sediment transport within the urban area, for large events, was dominated by the impact of the Combined Sewer Overflows discharging. Within these events peak suspended sediment concentration, SSC, were generally higher than the rural system. Within smaller events the main sediment source within the urban area was the surface runoff discharging directly to the urban river. Analysis of SSC and discharge relationships illustrated the different sources of sediment for contrasting events. Within the rural system clockwise hysteresis, indicating exhaustion of sediment supply, was noted for larger storms. The high temporal resolution monitoring has enabled a better understanding of sediment dynamics within the Bradford Beck system to be developed. The general conclusions drawn can provide guidance for addressing sediment related water quality issued in other urban systems.

Journal Article↗
PubMed2000

Effect of genetic merit, milk yield, body condition and lactation number on in vitro oocyte development in dairy cows.

The effects of milk yield, body condition score (BCS) and lactation number on the number of oocytes recovered and blastocysts formed were studied following in vitro maturation, fertilization and culture of bovine oocytes collected from 48 high and 46 medium genetic merit dairy cows in their first and third lactation. The cows were slaughtered between 125 and 229 d post partum. Ovaries were recovered, and 2- to 10-mm follicles were aspirated. Cleavage rate and number of blastocysts were determined at 44 h and 7 d after insemination, respectively. Oocytes from high genetic merit cows formed fewer blastocysts and had lower cleavage and blastocyst formation rates than those from medium genetic merit cows (0.36 +/- 0.19, 70.4 and 6.8% vs 0.85 +/- 0.22, 77.4 and 11.4%, respectively). The effect of milk production was tested by grouping cows in their third lactation into high and low groups. There was no difference in number of oocytes recovered and subsequent development into blastocysts between the cows in the high milk production group (4559 to 5114 kg, n = 20) and cows in the low yield (3162 to 3972 kg, n = 20) group (6.9 +/- 1.34 vs 8.9 +/- 1.32, respectively). The effect of BCS was tested by grouping cows in their first or third lactation into high and low groups. Cleavage and blastocyst formation rates were greater for oocytes from cows with a high BCS (3.3 to 4.0, n = 20) than a low BCS (1.5 to 2.5, n = 20) (75.7 vs 61.9% and 9.9 vs 3.0%, respectively). Cows in the first lactation yielded fewer oocytes (5.7 +/- 1.24) than cows in the third lactation (7.8 +/- 0.79). Thus, the quality of oocytes probably contributes to reduced fertility, often evident in high genetic merit dairy cows.

Animals↗
PubMed1994

Effect of recovery method on yield of bovine oocytes per ovary and their developmental competence after maturation, fertilization and culture in vitro.

An important aim of an oocyte recovery method is to maximize the number of oocytes per ovary which can be employed for in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC). In this study, primary bovine oocytes were collected by 2 methods: aspiration of visible follicles (2 to 6mm in diameter) or surface dissection in which the ovary surface is finely dissected. The oocytes were classified on the basis of cumulus cover and cytoplasmic appearance. The total number of oocytes and the yield of good-quality oocytes recovered per ovary by surface dissection and aspiration were 44.2 and 13.9 and 13.5 and 4.6 (P<0.05), respectively. When a sample group of selected oocytes recovered by each method was measured, no significant difference was found in the mean diameter (144.11m vs 142.54m). A representative sample of good-quality oocytes recovered by each method was put through the IVM/IVF/IVC procedure: no significant difference in cleavage rate, cleavage index or blastocyst yield was found. However, when the blastocyst yield was compared on a per ovary basis, a significant difference was observed in favor of surface dissection (3.30+/-0.46 vs 0.96+/-0.16;P<0.05). When unselected oocytes recovered by surface dissection of the ovaries were put through the standard embryo production system, an average of 15.4 blastocysts per dam was obtained.

Journal Article↗
PubMed1980

Lung function and symptoms of cigarette smokers related to tar yield and number of cigarettes smoked.

In a survey of over 18 000 male civil-servants, tar yield and number of cigarettes smoked daily were related to lung function and respiratory symptoms. Both phlegm production and airflow obstruction among smokers increased with daily cigarette consumption. Tar yield influenced phlegm production but not the degree of airflow obstruction. However, those smoking more than twenty cigarettes per day lost most of the advantage of smoking low-tar cigarettes since their phlegm production was the same as that of high-tar cigarette smokers. Ex-smokers had better lung function than current smokers with comparable total cigarette consumption; the difference between ex-smokers and current smokers was not related to the length of time that ex-smokers had abstained from smoking. Despite a reduction in phlegm production a change to low-tar cigarettes, may only be associated with an improvement in lung function if dialy cigarette consumption is also reduced. After stopping smoking there may be an initial improvement in lung function but ex-smokers never fully restore their lung function, no matter how long they have abstained from smoking. Although lower tar yield may reduce phlegm production and the risk of cancer, the development of airways obstruction may not be related to the tar content of cigarettes. Rather, the gaseous phase of tobacco smoke may contain the irritant agents leading to airways obstruction.

Adult↗
PubMed1997

Factors affecting the yield of cold-adapted influenza virus vaccine.

Various manipulations to production procedures have been investigated in order to discover methods to attain adequate or augmented titers of cold-adapted influenza virus (CAIV) vaccine. The methods modified include those used for reassortant selection and the determination of virus growth parameters. Increased infectivity titers were achieved through selection of high-yielding mutants by isolating multiple plaques during plaque purification of reassortant clones, as well as through optimization of egg incubation times, age, and lot for individual strains. Up to 6-fold increases in virus yield were obtained by selecting high yielding mutants, up to 9-fold increases were achieved by modifying egg incubation times, and a nearly 1 log increase was realized by determining the ideal egg age for individual strains.

Adaptation, Physiological↗
PubMed1997

Use of oligonucleotide probes for selecting potential high-yielding influenza reassortants.

A new method for rapid screening of high-yielding reassortants of influenza virus, as candidates for vaccine production, is described. Oligonucleotide probes specific for all the parent genes of A/PR/8/34 (PR8), except the HA and the NA were designed based on database information available for different influenza strains. Digoxigenin labelled probes were tested by slot-blot hybridizations to purified RNA from a panel of A/PR/8/34 wild type and A/PR/8/34 reassortant viruses. The results show that the vast majority of reassortants selected for their high growth yield had acquired the non-structural (NS), matrix (M) and RNA polymerase 2 (PB2) genes from the PR8 parent. It is proposed that probes for these genes provide the potential for a simple and rapid procedure for selection of candidate high-yield reassortants for vaccine production.

Genes, Viral↗