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Biomedical subjects

C Hudson

Publications and source records attributed to C Hudson.

At least 19 recordsLinked to original sources
PubMed2006

Reducing surgical outpatient waiting is not the solution to meeting the 2005 colorectal cancer target.

OBJECTIVES: The majority of colorectal cancers (CRC) are not diagnosed through the Rapid access route (RAR) and follow-ups (FU) may prolong outpatient-waiting time for new referrals. The aim of this study was to assess the relative contributions of an efficient colorectal clinic and a stringent colonoscopy booking system on the total journey time for CRC. PATIENTS AND METHODS: We reduced the number of follow-up appointments with the introduction of 'Paper clinics'. The composition of the new clinic was determined by the known cancer yield through RAR and non-RAR route. A prospective analysis of clinics and CRC journey times was undertaken from November 2003 for 13 months, with the new outpatient clinic template introduced in December 2003. This coincided with a stringent policy on referral pattern for colonoscopy. RESULTS: In our hospital, only 4% of RAR yield CRC. Seventy-five percent of our CRC are referred through the non-RAR route. Eighty-one percent of follow-ups in a 'paper clinic' were discharged. A flexible template for the outpatient clinics, introduced a corresponding reduction in follow-up and increased urgent and routine slots. There was a progressive drop in the follow-up to new ratio and the waiting times for routine and urgent category decreased from a median of 15.9 and 3.4 weeks to 6.7 and 0.7 weeks, respectively (P < 0.001). Average waiting times for all categories fell from 13.35 weeks in November 2003 to 3.5 weeks in December 2004, while the number of patients waiting less than 4 weeks rose from 46% to 71%. This was associated with reduction in total journey times from 93 days to 62 days (P < 0.05). DNA rates remained unaffected. CONCLUSION: Modifying outpatient clinic composition with 'paper clinics' reduces the waiting time for all referrals to a surgical clinic with a modest effect on CRC clinic waiting time. Reduction in the total waiting time to first treatment (for CRC) is due to reducing the demand on colonoscopy in favour of barium enema. Redirecting the flow of patients towards barium enema is perhaps one way of improving the existing CRC journey time to first treatment, within existing resources. Achieving the 62 day target for cancer journey time will be difficult unless traditional surgical clinic habits are challenged.

Ambulatory Care Facilities↗
PubMed2005

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema.

AIMS: To compare the macular capillary blood flow of patients with clinically significant diabetic macular oedema (DMO) with that of non-diabetic subjects and to determine the relation between blood flow and capillary leakage in patients with DMO. METHODS: The sample comprised 45 non-diabetic subjects (mean age 59 years) and 18 type 2 patients with clinically significant DMO (mean age 60 years). Macular capillary blood flow measurements were acquired using the Heidelberg retina flowmeter (HRF) and a 10 degrees x2.5 degrees scan field centred on the fovea. Fluorescein angiography was undertaken on each of the diabetic patients after the completion of HRF measurements. RESULTS: Temporal macular capillary blood flow was significantly lower for the patients with clinically significant DMO compared with age matched non-diabetic subjects (ANCOVA, p = 0.0011) while relative nasal-temporal asymmetry of macular capillary blood flow was significantly higher (p = 0.0125). Nasal-temporal asymmetry of macular capillary blood flow was significantly higher for the patients with DMO and capillary leakage within the scan area (two tailed t test, p = 0.0071). Macular capillary blood flow was always lower in areas of DMO and capillary leakage. CONCLUSION: Capillary blood flow was reduced in areas of DMO and capillary leakage, suggesting the presence of a localised perturbation of capillary blood flow regulation.

Aged↗
PubMed2005

Impact of simulated light scatter on scanning laser Doppler flowmetry.

AIM: To determine the impact of simulated light scatter on scanning laser Doppler flowmetry (SLDF) assessment of retinal capillary blood flow and retinal image quality. METHODS: One eye of 10 normal subjects (mean (SD) age 24 (1.7) years, range 22-27) was randomly selected. Varying concentrations of polystyrene microspheres were suspended in optically clear cells to simulate light scatter. The microsphere concentrations used were 0.05%, 0.03%, 0.02%, 0.01%, and a cell containing only water. LogMAR visual acuity and contrast sensitivity were measured both with and without cells. Optimal focus and alignment was established by acquiring three SLDF images each of the optic nerve head (ONH) and of the macula using the Heidelberg retina flowmeter (HRF) with no cell in place. SLDF images were subsequently acquired with each of the light scatter cells mounted in front of the HRF. The group mean retinal capillary blood flow was compared using repeated measures analysis of variance (reANOVA) as a function of microsphere concentration. RESULTS: Retinal capillary blood flow increased significantly in the ONH, nasal macula, fovea, and temporal macula with increasing microsphere concentration (p<0.0001). Using Dunnett's post hoc test, retinal capillary blood flow was found to be significantly increased relative to the no cell condition for the 0.03% and 0.05% cell concentrations. CONCLUSIONS: Simulated light scatter produces an artifactual increase in retinal capillary blood flow. The impact of cataract on SLDF measurements has yet to be determined.

Adult↗
PubMed2005

Frequency of seeing characteristics of the short wavelength sensitive visual pathway in clinically normal subjects and diabetic patients with focal sensitivity loss.

AIMS: To define the frequency of seeing (FOS) characteristics of the short wavelength (SW) sensitive visual pathway in clinically normal subjects and in diabetic patients with focal SW sensitivity loss. METHODS: For clinically normal subjects, FOS was assessed at two retinal locations (4.24 degrees and 9.90 degrees eccentricity) for both white on white (WW) and SW stimulus parameters. Inter-examination variability was quantified for the clinically normal subjects only. For patients with diabetes, FOS was assessed inside an area of focal SW sensitivity loss, and at the same eccentricity in the quadrant diametrically opposite, using SW stimulus parameters only. RESULTS: For clinically normal subjects, the group mean SW FOS slope was significantly flatter (p<0.0001) than that of WW at both locations. The coefficient of repeatability for SW FOS slope was+/-41.55 dB(-1) (relative to a group mean sensitivity of 23.98 dB(-1)) and+/-19.98 dB(-1) (group mean sensitivity 16.15 dB(-1)) for 4.24 degrees and 9.90 degrees , respectively. For the patients with diabetes, the group mean SW FOS slope was significantly flatter (p=0.020), and group mean SW threshold significantly higher (p=0.007) in the area of focal SW sensitivity loss than in that of the non-focal sensitivity loss. CONCLUSIONS: The results of this study suggest that the clinical utility of SW automated perimetry will be limited by a greater magnitude of measurement variability, as indicated by a flatter FOS slope, compared to conventional automated perimetry.

Adult↗
PubMed2004

Eccentricity and measurement variability and repeatability with the retinal thickness analyser.

AIMS: To define the variability and repeatability of retinal thickness measurements using the retinal thickness analyser (RTA) and to elucidate any interaction between eccentricity (that is, position relative to the fovea) and variability and repeatability. METHODS: The sample comprised 20 normal subjects of mean age 33 years. Each subject attended for two visits. Repeated RTA scans were acquired centred on the fovea and for any one of the four possible non-foveal scan areas. The mean retinal thickness (+SD) was calculated for a series of concentric circular bands centred on fixation. A repeated measures analysis of variance (ANOVA) was used to determine any significant interaction between the variability of RTA thickness values and eccentricity. RESULTS: The group mean coefficient of variation and coefficient of repeatability were highest at the fovea. The repeated measures ANOVA revealed that the within test variability of RTA measurements varied significantly with eccentricity (p<0.0001). Similarly, the between test repeatability varied significantly with eccentricity (p = 0.045). CONCLUSION: The significantly elevated within test variability and between test repeatability in the foveal area need to be considered when using the RTA to evaluate patients with macular disease.

Adult↗
PubMed2003

Correlation of a scanning laser derived oedema index and visual function following grid laser treatment for diabetic macular oedema.

AIM: To correlate change of an oedema index derived by scanning laser tomography with change of visual function in patients undergoing grid laser photocoagulation for clinically significant diabetic macular oedema (DMO). METHODS: The sample comprised 24 diabetic patients with retinal thickening within 500 micro m of the fovea. Inclusion criteria included a logMAR visual acuity of 0.25, or better. Patients were assessed twice before a single session of grid laser treatment and within 1 week of, and at 1, 2, 4, and 12 weeks after, treatment. At each visit, patients underwent logMAR visual acuity, conventional and short wavelength automated perimetry (SWAP), and scanning laser tomography. Each visual function parameter was correlated with the mean oedema index. The mean oedema index represented the z-profile signal width divided by the maximum reflectance intensity (arbitrary units). A Pearson correlation coefficient (Bonferroni corrected) was undertaken on the data set of each patient. RESULTS: 13 patients exhibited significant correlation of the mean oedema index and at least one measure of visual function for the 10 degrees x 10 degrees scan field while 10 patients correlated for the 20 degrees x 20 degrees scan field. Seven patients demonstrated correlation for both scan fields. Laser photocoagulation typically resulted in an immediate loss of perimetric sensitivity whereas the oedema index changed over a period of weeks. Localised oedema did not impact upon visual acuity or letter contrast sensitivity when situated extrafoveally. CONCLUSIONS: Correlation of change of the oedema index and of visual function following grid laser photocoagulation was not found in all patients. An absence of correlation can be explained by the localised distribution of DMO in this sample of patients, as well as by differences in the time course of change of the oedema index and visual function. The study has objectively documented change in the magnitude and distribution of DMO following grid laser treatment and has established the relation of this change to the change in visual function.

Aged↗
PubMed2002

Early steps in the formation of neural tissue in ascidian embryos.

Ascidians are simple invertebrate chordates whose lineage diverged from that of vertebrates at the base of the chordate tree. Their larvae display a typical chordate body plan, but are composed of a remarkably small number of cells. Ascidians develop with an invariant cell lineage, and their embryos can be easily experimentally manipulated during the cleavage stages. Their larval nervous system is organised in a similar way as in vertebrates but is composed of less than 130 neurones and around 230 glial cells. This remarkable simplicity offers an opportunity to understand, at the cellular and molecular levels, the ontogeny and function of each neural cell. Here, we first review the organisation of the ascidian nervous system and its lineage. We then focus on the current understanding of the processes of neural specification and patterning before and during gastrulation. We discuss these advances in the context of what is currently known in vertebrates.

Animals↗
PubMed2002

Effects of fat adaptation on glucose kinetics and substrate oxidation during low-intensity exercise.

This study was designed to determine the effects of fat adaptation on carbohydrate and fat oxidation in conditioned horses during low-intensity exercise. Five mature Arabians were studied. The study was conducted as a crossover design with 2 dietary periods, each of 10 week's duration: a) a control (CON) diet, and b) a fat-supplemented (FAT) diet. The total amount of digestible energy (DE) supplied by the fat in the CON and FAT diets was 7% and 29%, respectively. During each period, the horses completed exercise tests at the beginning of the period (Week 0) and after 5 and 10 weeks on the diet. Tests consisted of 90 min of exercise at a speed calculated to elicit 35% VO2max on a treadmill inclined to 3 degrees. Oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured at 15-min intervals. For determination of glucose kinetics, a stable isotope ([6-6-d2] glucose) technique was used. Compared to the CON diet, FAT diet consumption for 5-10 weeks was associated with an altered metabolic response to low-intensity exercise, as evidenced by a more than 30% reduction in the production and utilisation of glucose; a decrease in RER; a decrease in the estimated rate of whole-body carbohydrate utilisation; and an increase in the whole-body rate of lipid oxidation during exercise.

Adaptation, Physiological↗
PubMed2002

Comparison of the metabolic responses of trained Arabians and Thoroughbreds during high- and low-intensity exercise.

In order to compare the metabolic responses to exercise in 2 similarly managed breeds of horses, 5 Arabian (AR) and 5 Thoroughbred (TB) horses, fed an identical diet with a similar diet and exercise training programme for the 2 preceding months, undertook 3 treadmill (3 degree incline) trials with a minimum of 7 days between tests: 1) an incremental test (MAX) for determination of aerobic capacity, V(LA4) and lactate threshold (LT; the percentage of VO2max when plasma lactate = 4 mmol/l); 2) a single high-speed exercise test (SPR) at 115% VO2max for estimation of maximal accumulated oxygen deficit (MAOD) and 3) a 90 min test at 35% VO2max (LO). VO2max (P<0.001) and running speed (P<0.05) at VO2max were higher in TB (mean +/- s.e. 154 +/- 3 ml/kg/min at 12.9 +/- 0.5 m/s) than in AR (129 +/- 2.5 ml/kg/min at 11.8 +/- 0.2 m/s). Total run time during MAX was greater (P<0.05) in TB (10.5 +/- 0.5 min) than in AR (93 +/- 0.3 min). However, V(LA4) and LT were not different between groups. Run time during SPR (TB 149 +/- 16; AR 109 +/- 11 s) and MAOD (TB 88 +/- 4; AR 70 +/- 6 ml O2/kg) were higher (P<0.05) in the TB group. During LO, FFA were higher (P<0.05) and the respiratory exchange ratio (RER) lower (P<0.05) in AR than in TB between 60 and 90 min, of exercise, indicating a greater use of fat for energy. These metabolic differences may reflect breed variation in muscle fibre types. However, further studies are needed to determine the mechanisms underlying the apparent breed differences in energy metabolism during exercise.

Animals↗
PubMed2001

Induction of anterior neural fates in the ascidian Ciona intestinalis.

The sensory vesicle of ascidians is thought to be homologous to the vertebrate forebrain and midbrain (Development 125 (1998) 1113). Here we report the isolation of two sensory vesicle markers in the ascidian Ciona intestinalis, which are homologs of vertebrate otx and gsx homeobox genes. By using these markers to analyze the induction of anterior neural tissue in Ciona, we find that the restriction of anterior neural fate to the progeny of the anterior animal blastomeres is due to a combination of two factors. The vegetal blastomeres show a differential inducing activity along the anterior-posterior axis, while the competence to respond to this inducing signal is markedly higher in the anterior animal blastomeres than in the posterior animal blastomeres. This differential competence to respond is also observed in response to bFGF, a candidate neural inducer in ascidians (J. Physiol. 511.2 (1998) 347) and can be detected by the gastrula stage. Our results, however, indicate that bFGF can only induce a subset of the responses of the endogenous inducer, suggesting that additional signals in the embryo are necessary to induce a fully patterned nervous system.

Amino Acid Sequence↗
PubMed2001

Incidence of class 1 and 2 integrases in clinical and commensal bacteria from livestock, companion animals, and exotics.

Many pathogenic and commensal organisms are multidrug resistant due to exposure to various antibiotics. Often, this antimicrobial resistance is encoded by integrons that occur on plasmids or that are integrated into the bacterial chromosome. Integrons are commonly associated with bacterial genera in the family Enterobacteriaceae. We determined that class 1 integrases were present in approximately 46% of the isolates from the family Enterobacteriaceae; class 2 integrases were present only among Escherichia coli and Salmonella isolates. Seven percent of veterinary isolates were positive for class 3 integrase by DNA-DNA hybridization but could not be confirmed to be positive by PCR. None of the veterinary isolates possessed the class 4 integrase gene. The distribution of these integrase genes was variable within the members of the family Enterobacteriaceae when some or all integrase classes were absent from a particular genus. There was also considerable variability in the distribution of these integrases within a species, depending on the animal host. Unlike the class 1 integrases, the other integrase class, intI2, appears to be more restricted in its distribution among the members of the family Enterobacteriaceae. There is also considerable variability in the distribution of the class 1 integrases within E. coli strains isolated from different food animals. The class 1 integrases are the most widely disseminated of the four classes among the members of the family Enterobacteriaceae from both the clinical and normal flora of animals. This is the first report to closely examine the distribution of class 2 integrases in members of the family Enterobacteriaceae isolated in the United States.

Animals↗
PubMed2001

Relation between macular morphology and visual function in patients with choroidal neovascularisation of age related macular degeneration.

AIM: To examine the relation between three measures of visual function (distance acuity, near acuity, and contrast sensitivity) and specific fluorescein angiographic characteristics of the macular lesion in patients with subfoveal choroidal neovascularisation (CNV) due to age related macular degeneration (AMD). METHODS: Visual evaluation and digital fundus fluorescein angiography were performed in 93 patients with subfoveal CNV. Standard morphometric techniques were used on two frames from the angiographic series closest to 30 seconds and 60 seconds respectively, to ascertain total lesion size (defined as the entire area of abnormal fluorescence), the size of the classic component, and the distance from the fovea to the closest point of healthy retina. Correlations were sought using Pearson's correlation coefficients. Stepwise regression was used to minimise multiple colinearity. RESULTS: When the study eye was the better eye of a patient's pair of eyes, the strongest correlation was between the size of the classic component and contrast sensitivity (r= 0.48, p <0.001) and was highly significant. When the study eye was the worse eye, significant correlations were observed between total lesion size and all three measures of visual function. The strongest correlation was observed between overall lesion size and contrast sensitivity (r = 0.52, p <0.001). CONCLUSIONS: This study has shown that the status of the study eye (that is, better or worse eye of a pair of eyes) influences the impact of macular pathology in AMD on visual function. The distance of the fovea from healthy retina was found to be an important factor in predicting visual function.

Aged↗
PubMed2001

[Acute mountain sickness at 3500 and 4250 m. A study of symptom, incidence and severity].

BACKGROUND: Acute Mountain Sickness (AMS) refers to signs and symptoms associated with hypobaric hypoxia. Its reported incidence is highly variable. AIM: To determine the incidence of AMS symptoms and severity at 3,500 and 4,250 m above sea level. SUBJECTS AND METHODS: A population of 362 soldiers without former exposure to altitude was studied. AMS symptoms, were assessed by an extensively used standard questionnaire (Lake Louise), applied 36-72 hours after exposure to high altitude. RESULTS: A group of 200 recruits ascended to Putre (3,500 m) and a second group (162) ascended to Alto Pacollo (4,250 m). The incidence of AMS was 28% and 60% respectively (p < 0.05). Headaches and sleeping difficulties were the most frequent symptoms at both altitudes. Furthermore, severe digestive problems and dizziness were described in a high proportion of individuals at both 3,500 and 4,250 m. CONCLUSIONS: The prevalence of AMS in this study is similar to that reported elsewhere at equivalent altitudes.

Acute Disease↗
PubMed2000

Lack of utility of standard labor curves in the prediction of progression during labor induction.

OBJECTIVE: This study was undertaken to determine whether patients undergoing labor induction can be reliably evaluated by means of standard labor assessment curves. STUDY DESIGN: In this retrospective chart review of 123 patients who underwent cervical ripening and induction of labor, Friedman's standard labor curves were used for comparison. Statistical analysis was performed with the Student t test. RESULTS: Nulliparous and parous patients undergoing cervical ripening spent more time in active-phase labor than standard expectations of labor progression would indicate (12.7 +/- 7.8 vs 5. 9 +/- 3.4 hours for nulliparous women, P <.001; 7.9 +/- 6.4 vs 2.5 +/- 1.5 hours for parous women, P <.001). Nulliparous and parous patients who were delivered vaginally spent more time in active labor than did their respective standard historical control populations (10.3 +/- 8.0 vs 5.9 +/- 3.4 hours for nulliparous women, P <.001; 7.0 +/- 6.0 vs 2.5 +/- 1.5 hours for parous women, P <. 001). CONCLUSION: Standard methods for the evaluation of labor adequacy and prediction of the likelihood of vaginal delivery may not apply to patients undergoing cervical ripening.

Adult↗
PubMed2000

Characterization of chloramphenicol and florfenicol resistance in Escherichia coli associated with bovine diarrhea.

Florfenicol, a veterinary fluorinated analog of thiamphenicol, is approved for treatment of bovine respiratory pathogens in the United States. However, florfenicol resistance has recently emerged among veterinary Escherichia coli isolates incriminated in bovine diarrhea. The flo gene, which confers resistance to florfenicol and chloramphenicol, has previously been identified in Photobacterium piscicida and Salmonella enterica serovar Typhimurium DT104. The flo gene product is closely related to the CmlA protein identified in Pseudomonas aeruginosa. The cmlA gene confers nonenzymatic chloramphenicol resistance via an efflux mechanism. Forty-eight E. coli isolates recovered from calves with diarrhea, including 41 that were both chloramphenicol and florfenicol resistant, were assayed for the presence of both flo and cmlA genes. Forty-two of the 44 isolates for which florfenicol MICs were > or =16 microg/ml were positive via PCR for the flo gene. All E. coli isolates for which florfenicol MICs were < or =8 microg/ml were negative for the flo gene (n = 4) Twelve E. coli isolates were positive for cmlA, and chloramphenicol MICs for all 12 were > or =32 microg/ml. Additionally, eight isolates were positive for both flo and cmlA, and both florfenicol and chloramphenicol MICs for these isolates were > or =64 microg/ml. DNA sequence analysis of the E. coli flo gene demonstrated 98% identity to the published GenBank sequences of both serovar Typhimurium flo(St) and P. piscicida pp-flo. The flo gene was identified on high-molecular-weight plasmids of approximately 225 kb among the majority of florfenicol-resistant E. coli isolates. However, not all of the florfenicol-resistant E. coli isolates tested contained the large flo-positive plasmids. This suggests that several of the E. coli isolates may possess a chromosomal flo gene. The E. coli flo gene specifies nonenzymatic cross-resistance to both florfenicol and chloramphenicol, and its presence among bovine E. coli isolates of diverse genetic backgrounds indicates a distribution much wider than previously thought.

Animals↗
PubMed1999

Clinical subtyping reveals significant differences in calcium-dependent phospholipase A2 activity in schizophrenia.

BACKGROUND: Inconsistent results in the study of phospholipid metabolism in schizophrenia may reflect the heterogeneous nature of the illness(es). Differences in patients' responses to niacin, a compound causing vasodilation via stimulation of phospholipid dependent signaling cascades, defines more homogeneous patient subgroups in which the rate limiting enzyme of this signaling pathway, phospholipase A2 (PLA2), can be studied. METHODS: Subjects were categorized as niacin-insensitive (10 schizophrenic patients and 1 control) or niacin-sensitive (13 schizophrenic patients and 29 controls). Comparisons of serum calcium-dependent PLA2 were undertaken with and without consideration of niacin sensitivity. RESULTS: Significantly more schizophrenic patients were niacin-insensitive than controls (chi 2 (1) = 12.8, p < .001). Comparison of mean serum calcium-dependent PLA2 level of all schizophrenic subjects with all healthy controls revealed no statistical difference (t(51) = .79, NS). Subtyping the schizophrenia group by niacin sensitivity/insensitivity, however, allowed significant differences to emerge (F(2,49) = 4.40, p = .018). Post-hoc tests showed the mean PLA2 activity level of niacin-sensitive subjects was lower than that of healthy subjects. CONCLUSIONS: Treatment strategies which increase calcium-dependent PLA2 activity may aid in reducing states of excess dopaminergic activity by activating second messenger systems rather than receptor blockade.

Adult↗
PubMed1999

Postprandial lipid, glucose, insulin, and cholecystokinin responses in men fed barley pasta enriched with beta-glucan.

BACKGROUND: Fiber regulates the rate and site of lipid and carbohydrate digestion and absorption and thus can modify the alimentary responses to a meal. When fiber sources containing viscous polysaccharides are included in a meal, a slower rate of carbohydrate and lipid absorption will modify the alimentary hormone and lipid responses. OBJECTIVE: We investigated in 11 healthy men the response of insulin, glucose, cholecystokinin, and lipid to 2 test meals containing beta-glucan. DESIGN: One of the meals was high in fiber (15.7 g) and the other meal was low in fiber (5.0 g). The low-fiber meal contained pasta made with wheat flour. The high-fiber meals contained pasta prepared by replacing 40% of the wheat with 2 types of barley flour: barley naturally high in beta-glucan and the other a flour enriched in beta-glucan during processing. RESULTS: Plasma glucose and insulin concentrations increased significantly after all meals but the insulin response was more blunted after the barley-containing meals. The test meals were low in fat (25% of energy) but elicited an increase in plasma triacylglycerol and cholecystokinin. Cholecystokinin remained elevated for a longer time after the barley-containing meals. After the low-fiber meal, plasma cholesterol concentrations did not change significantly; however, 4 h after the barley-containing meals, the cholesterol concentration dropped below the fasting concentration and was significantly lower than that after the low-fiber meal. CONCLUSIONS: Carbohydrate was more slowly absorbed from the 2 high-fiber meals. Consumption of the barley-containing meals appeared to stimulate reverse cholesterol transport, which may contribute to the cholesterol-lowering ability of barley.

Adult↗