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S J Davis

Publications and source records attributed to S J Davis.

At least 109 records · Page 6Linked to original sources
PubMed1987

The DNase I generated disomal series is coherent to 16N. Implications for coiling models of chromatin structure.

The disomal series generated by the digestion of chromatin with DNase I has been followed to its highest orders using Klenow end-labelling and field-inversion gel electrophoresis to maximise the resolution of large DNA fragments. The series is coherent to the 16N level and as such is incompatible with the most structurally acceptable coiling models. We propose that this is evidence for the general unsuitability of coiling models and is support for the existence of simple 'back-to-back' double-stranded structures within chromatin.

Animals↗
PubMed1987

Cranial CT scan appearances that correlate with patient outcome in acute stroke.

Certain clinical features are known to correlate with patient outcome in acute stroke, but the potential of cranial CT scan as an aid to predicting recovery after stroke remains unclear. In a prospective study, 178 acute stroke patients admitted to Royal Perth Hospital were assessed by 4 neurologists; 150 cranial CT scans were performed and these were reviewed by an independent radiologist. CT lesion characteristics were cross-tabulated against clinical indices of patient outcome. Lesions greater than 50 cm3 in volume were associated with a 23% mortality compared to a 5% mortality for lesions smaller than 50 cm3. The mortality rate from intracerebral haemorrhage was 25% compared to 9% for other disease. Of patients whose CT scan showed a mass effect, 35% had an altered mental state at discharge compared to only 2% of those without a mass effect. Of the patients with deep white matter lesions, 35% had an altered mental state at discharge compared to only 13% of patients with lesions in other sites, and only 50% were discharged home compared to 77% of patients with lesions in other sites. CT scan features that correlated significantly with a poor outcome following acute stroke were large lesion size, intracerebral haemorrhage, mass effect and deep white matter lesions.

Cerebral Hemorrhage↗
PubMed1986

Sulphation and the vegetative growth of Dictyostelium discoideum.

The utilization of [35S]sulphate by bacterially grown amoebae of Dictyostelium discoideum strain NP73 was examined in this study. During vegetative growth the sulphation of at least ten macromolecules was observed. These macromolecules had molecular masses less than 66 kDa and isoelectric points below 5. Simple tests indicated that the sulphate linkage was periodate-sensitive but not acid-labile which implied that carbohydrate moieties, rather than tyrosine residues, were sulphated. Pulse-chase experiments indicated that the sulphated macromolecules were extremely stable during vegetative growth, but that secretion occurred on starvation, resulting in the loss of the sulphated macromolecules to the extracellular medium. Incorporation of [35S]sulphate into these macromolecules by amoebae declined rapidly within 2 h of starvation on membrane filters. In contrast, incorporation by amoebae starving in suspension culture continued for 6-8 h. Similar patterns of [35S]sulphate incorporation were observed for two other strains of D. discoideum (strains AX2 and NC4) and for Polysphondylium violaceum. Since in a previous study it was shown that the sulphation inhibitor, sodium selenate, arrests the growth of D. discoideum [Davis, S.J. & Wheldrake, J.F. (1985) FEMS Micro Lett. 30, 353-358], it is suggested that the sulphation of these macromolecules is necessary for the vegetative growth of D. discoideum.

Dictyostelium↗
PubMed1986

The role of colonoscopy in the assessment of patients with colorectal cancer.

A retrospective review of 176 patients with adenocarcinoma of the colon who underwent total colonoscopy preoperatively demonstrated synchronous carcinomas in 3.4 percent and synchronous polyps in 55.1 percent. Full-column barium enemas (68 patients) failed to identify cancer in 22 percent of patients and synchronous polyps in 58 percent of patients, a statistically significant (P less than 0.001) number of false-negative examinations. Double-contrast barium enemas (30 patients) failed to identify cancer in 27 percent of patients and synchronous polyps in 42 percent of patients, also a statistically significant (P less than 0.007) number of false-negative examinations. Full column and air contrast barium enemas identified all index cancers with distant metastases. Air-contrast barium enemas failed to identify 40 percent of "early" index cancers (confined to the bowel wall, negative nodes), and full-column barium enemas failed to identify 32 percent. The incidence of synchronous carcinoma and polyps underscores the need for total colon evaluation when a primary carcinoma is detected. Because of the poor accuracy of barium studies, total colonoscopy is the method of choice for this evaluation.

Adenocarcinoma↗
PubMed1985

Characteristics of breast cancer in women over 80 years of age.

The records of 198 women over 80 years of age with breast cancer were reviewed to identify characteristics of breast cancer and to determine the effect of age in management of the disease in elderly women. Twenty percent of the patients were not staged at diagnosis. Axillary lymph node status was undetermined in 40 percent of the patients because operation was limited to lumpectomy or mastectomy (either simple or total). Complications were related to the operative wound. Breast cancer and cardiovascular disease accounted for 115 of 146 deaths and the 5 year survival rate was 35.6 percent. We have concluded that breast cancer in elderly women can be treated with appropriate surgical therapy and should not be limited because of age.

Adenocarcinoma↗
PubMed1985

Effect of intestinal location on growth and function of neomucosa.

Growing intestinal neomucosa in patched intestinal defects has been investigated as a means of permanently increasing the absorptive capacity in the short bowel syndrome. Several factors, including luminal contents, appear to affect the growth and function of the neomucosa. The purpose of this study was to compare function and rate of growth of neomucosa in patched defects of the jejunum and ileum. In both the jejunum and ileum of 11 New Zealand white male rabbits 2 X 5-cm patched intestinal defects were created using the serosal surface of adjacent colon. The animals were sacrificed at 4 weeks (n = 6) and 8 weeks (n = 5) after operation. Grossly there was more complete coverage of the defect by neomucosa in the ileum at both 4 and 8 weeks (99.1 +/- 1.1% vs 92.6 +/- 6.3% overall P less than 0.005). Villous height of the ileal neomucosa was similar to normal mucosa at 8 weeks (209 +/- 21 vs 244 +/- 18 m) but was significantly less in the jejunum (209 +/- 16 vs 273 +/- 16 m, P less than 0.005). Glucose uptake by neomucosa was greater in the ileum than the jejunum (3.34 +/- .84 vs 2.39 +/- .46 nmole/min/mg, P less than 0.05) but was similar to normal mucosa at both sites. Disaccharidase activity (lactase, sucrase, and maltase) was similar in both jejunum and ileum but was significantly less in ileal neomucosa than in normal mucosa (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Insertion of Hickman catheters. A comparison of cutdown and percutaneous techniques.

The insertion of Hickman catheters is useful in providing long-term vascular access in patients with a variety of conditions. Recently, enthusiasm has developed for the percutaneous insertion of the catheter because of the speed and ease of insertion. The insertion of 82 Hickman catheters in adults was reviewed. Thirty (94%) of 32 patients had a catheter placed successfully using a cutdown technique with success in 75 per cent of patients with the initial cutdown. Catheter placement was successful in 48 (96%) of the 50 patients with the percutaneous technique. The average operating time was 77 min for the cutdown technique compared with 33 min with percutaneous insertion. The overall complication rate was 18 per cent using the cutdown technique and 16 per cent for the percutaneous technique. The percutaneous technique for inserting Hickman catheters results in a much shorter operating time with minimal morbidity. As with any subclavian puncture, however, there is the risk of significant complications. The cutdown technique should be considered in patients with coagulopathy and when difficulty performing a percutaneous insertion is anticipated.

Adolescent↗
PubMed1983

Aggressive diagnostic approach indicated in testicular sarcoidosis.

A twenty-nine-year-old black male presented with a testicular mass and hilar adenopathy. Histologic sections of the testis showed the 3 by 2 by 2-cm mass was an inflammatory granuloma due to sarcoidosis. The epididymides were involved bilaterally. The initial differential diagnosis included: sarcoidosis, testicular neoplasm, an infectious process, or a combination of the three. Biopsy of the testicle is recommended to confirm the diagnosis of sarcoidosis. We believe there are only 6 reported cases of clinically detected testicular sarcoidosis.

Adult↗
PubMed1983

Measurement of serum theophylline concentrations using a modified Ames TDA system.

Results are presented which show that the Ames TDA Theophylline kit provides an accurate and reliable method of measuring the concentration of theophylline in plasma. It may be used with a shortened incubation time (5 min) without loss of accuracy, and a single calibration curve can be used over a 3-week period. There is an acceptable precision at all assayed levels (coefficient of variation, 3.3%) and results obtained for patients' samples correlate well with those obtained using liquid chromatography (y = 0.02 + 1.06x, r = 0.99) and enzyme immunoassay (y = 0.58 + 1.03x, r = 0.99).

Bilirubin↗
PubMed1983

A critical evaluation of a new fluorescence immunoassay system for the measurement of serum phenytoin concentrations.

Results are presented which show that the Ames TDA tm phenytoin kit may be used with a shortened incubation time (5 minutes) and that, using a Fluorostat tm instrument, a single calibration curve can be stored and used effectively over a three-week period. The importance of temperature control when using a single calibration curve is emphasised. An unexplained finding was that higher results were obtained for phenytoin concentrations up to about 15 mg/l with increasing incubation temperature. There was acceptable precision of measurement at all levels of phenytoin concentration, and there was no significant interference by haemoglobin, bilirubin, or lipids. The TDA results correlated well with those obtained using liquid chromatography (y = 0.39 + 0.98x, r = 0.98, where y = TDA and x = HPLC) and enzyme immunoassay (y = 0.08 + 0.93x, r = 0.96, where y = TDA and x = EIA).

Bilirubin↗
PubMed1981

Brightness effects on color pecking preferences in dark-hatched domestic chicks.

Color pecking preferences in day-old, dark-hatched domestic chicks of 2 breeds were studied as a function of (1) target luminance (dim, medium, or bright) when testing was in darkness and in the light (Experiments I and II): (2) method of equilibrating target brightnesses (i.e., objectively or subjectively: Experiments III and IV); and (3) ambient brightness (dim, medium, or bright; Experiment IV). White Leghorns were found to peck sooner and more often than New Hampshires. Under all conditions of target and ambient brightness, results revealed the previously reported bimodal (V-shaped) color preference function with peak preferences in the blue-violet and orange regions of the spectrum and minimal at green. The only brightness factor that affected the V-shaped function was dark-adapted vs light-adapted viewing, that is, the chicks showed a slight shift away from red and/or a slightly more negative slope with light adaptation.

Animals↗
PubMed1979

Combined intravenous miconazole and intrathecal amphotericin B for treatment of disseminated coccidioidomycosis.

A patient received a previously unreported combination of intravenous miconazole and intrathecal amphotericin B for the treatment of disseminated coccidioidomycosis with central nervous system involvement. After first having been treated with amphotericin B, followed by a course of miconazole therapy, the patient responded with remarkable clinical and serologic improvement to the combination of intrathecal amphotericin B and intravenous miconazole. The combination should be considered in the treatment of disseminated coccidioidomycosis with central nervous system involvement.

Adult↗
PubMed1978

Chick colour approach preferences are altered by cold stress; colour pecking and approach preferences are the same.

Colour approach preferences in 1-day-old New Hampshire and White Leghorn chicks were assessed by choice preference tests between pairs of differently coloured floors, illuminated by light passed through different interference filters and adjusted to equal luminance. In experiment 1, the preferences found closely resembled colour pecking preferences reported previously for domestic chicks, e.g. a preference for blue over green. Experiment 2 showed that the latter preference could be reversed by cold stress. That is, chicks tested similarly but in a cold noisy room (18.9 C) preferred green over blue. Experiment 3 eliminated the role of noise in this reversal effect, since chicks tested in a warm noisy room showed the normal blue over green preference. It was concluded, in disagreement with prior findings and their interpretations, that chick colour pecking and approach preferences are normally the same, not different, and certainly not spectral mirror-image reversals. Instead, a more restricted preference reversal (i.e. in the blue-green spectral regions) occurs as a result of cold stress.

Animals↗
PubMed1978

Recurrent atrial fibrillation with nausea and vomiting.

Atrial fibrillation occurred twice during episodes of severe nausea and vomiting in a previously healthy 40-year-old male with new onset of Meniere's syndrome (tinnitus, vertigo, deafness). No organic cause was identified to explain the arrhythmia. Holter monitoring, maximal treadmill stress testing, and sinus node recovery times were normal. Intense vagal stimulation, subsequent bradycardia, and dispersion of atrial tissue refractory period is the likely explanation for this arrhythmia.

Atrial Fibrillation↗