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Biomedical subjects

M Nimmo

Publications and source records attributed to M Nimmo.

11 recordsLinked to original sources
PubMed2005

Combining HPLC pigment markers and ecological similarity indices to assess phytoplankton community structure: an environmental tool for eutrophication?

A new tool combining the use of HPLC pigment markers with ecological similarity indices, to provide a fast and effective environmental tool for monitoring water quality, was investigated. HPLC pigment concentrations from a 4-year time series data set (2000-2003) from the western English Channel were used to calculate six similarity indices to assess changes in phytoplankton community structure. Indices obtained from HPLC data were compared with those produced from the corresponding phytoplankton biomass derived from microscopic analysis. Multivariate RELATE analyses (P<0.001) suggested that there was little loss of information when species biomass data were grouped into higher taxonomic levels, thereby providing justification for the use of pigment markers. To test the proposed methodology, product moment (r) and Spearman's rank (r(s)) correlation analyses were performed. Highly significant correlations (P<0.01, Canberra Metric: P<0.05) between percentage similarities derived from phytoplankton class biomass and pigment markers were found for all indices when data were pooled (n=104). A Mann-Whitney U-test suggested that indices were more sensitive to changes in relative biomass than pigment concentrations; however, pigment data also produced statistically significant findings (P<0.05). Combining HPLC pigment markers and ecological similarity indices to assess phytoplankton community structure has advantages over microscopy in that it is rapid, reproducible and better suited to large-scale environmental monitoring. We present a basic protocol for implementing this new tool using a suite of similarity indices into environmental monitoring of phytoplankton communities.

Chromatography, High Pressure Liquid↗
PubMed2003

The use of ultrasound as an aid in the diagnosis of giant cell arteritis: a pilot study comparing histological features with ultrasound findings.

AIMS: We present our preliminary experience with the use of ultrasound in aiding the diagnosis of giant cell arteritis (GCA). Schmidt et al have previously described a hypoechoic or "halo" effect surrounding the walls of affected arteries on examination with ultrasound. We illustrate these features and explore the attributes and limitations of this technique. METHOD: Two groups of patients were recruited: (1) patients with suspected GCA awaiting temporal artery biopsy and (2) patients with no history or symptoms of GCA of a similar age group. All the recruited patients underwent ultrasound examination of both temporal arteries. The findings on ultrasound were compared with the results of the histological specimens in group 1. For this study, the histological findings alone were used to define if a patient was suffering from GCA. No biopsies were taken in the patients in group 2. RESULTS: Out of 26 patients with suspected GCA, seven patients were found to be positive on biopsy, of which six had been identified on ultrasound. Six patients were found to be false positive on ultrasound, but all had moderate-to-severe features of arteriosclerosis on histology. A total of 13 patients were found to be negative on ultrasound and negative on biopsy for GCA, two of these patients had histological features of arteriosclerosis. In the group with no symptoms of GCA (12 patients), in two patients hypoechoic areas were detected. The results presented give a sensitivity of 86%, specificity of 68%, and positive predictive value of 50% for the use of ultrasound in the diagnosis of GCA. CONCLUSIONS: This preliminary study indicates that this test may be helpful in those patients with symptoms suggestive of GCA, but currently we cannot recommend any change of present practice.

Aged↗
PubMed2002

Trace metal uptake by the Chinese mitten crab Eriocheir sinensis: the role of osmoregulation.

Changes in salinity affect the bioavailability and consequent uptake of trace metals by euryhaline invertebrates. In many cases, salinity-related effects on metal uptake can be explained by changes in chemical speciation but salinity may also influence uptake indirectly through its action on osmoregulatory mechanisms. Specifically, it can be hypothesised that trace metal uptake may be reduced at salinities approaching the isosmotic point of a species because, at this point, there is reduced activity of ionic exchange pumps. The present study tested this hypothesis using the Chinese mitten crab, Eriocheir sinensis, a hyper-hypoosmoregulator with an isosmotic point around 33 per thousand. Crabs were exposed to radio-labelled cadmium and zinc at 23, 33 and 43 per thousand for 4 days. To eradicate speciation effects, crabs were exposed to the same concentration of the radio-labelled free metal ion (estimated using MineQL computer software) at each salinity. Haemolymph samples were taken daily and radio-labelled metal concentrations were estimated from radioactivity counts and used to provide relative measures of metal uptake. Neither cadmium nor zinc uptake was lowest at the isosmotic point. The uptake of cadmium increased significantly with increase in salinity, while the uptake of zinc showed no significant change with increased salinity. Thus changes in trace metal uptake rates in E. sinensis do not appear to be controlled only by changes in free metal ion concentrations. The different effects of salinity change on the uptake of cadmium and zinc (in the absence of free metal ion change) also indicate that physiological responses to osmotic change alone do not control metal uptake rates for this species.

Animals↗
PubMed2001

Effects of active, passive or no warm-up on metabolism and performance during high-intensity exercise.

The aim of this study was to determine the influence of type of warm-up on metabolism and performance during high-intensity exercise. Eight males performed 30 s of intense exercise at 120% of their maximal power output followed, 1 min later, by a performance cycle to exhaustion, again at 120% of maximal power output. Exercise was preceded by active, passive or no warm-up (control). Muscle temperature, immediately before exercise, was significantly elevated after active and passive warm-ups compared to the control condition (36.9 +/- 0.18 degrees C, 36.8 +/- 0.18 degrees C and 33.6 +/- 0.25 degrees C respectively; mean +/- sx) (P< 0.05). Total oxygen consumption during the 30 s exercise bout was significantly greater in the active and passive warm-up trials than in the control trial (1017 +/- 22, 943 +/- 53 and 838 +/- 45 ml O2 respectively). Active warm-up resulted in a blunted blood lactate response during high-intensity exercise compared to the passive and control trials (change = 5.53 +/- 0.52, 8.09 +/- 0.57 and 7.90 +/- 0.38 mmol x l(-1) respectively) (P < 0.05). There was no difference in exercise time to exhaustion between the active, passive and control trials (43.9 +/- 4.1, 48.3 +/- 2.7 and 46.9 +/- 6.2 s respectively) (P= 0.69). These results indicate that, although the mechanism by which muscle temperature is elevated influences certain metabolic responses during subsequent high-intensity exercise, cycling performance is not significantly affected.

Adult↗
PubMed1999

Prognostic factors in Paget's disease of the vulva: a study of 21 cases.

Twenty-one cases of vulvar Paget's disease were studied to assess possible prognostic indicators, including presence and depth of invasion, status of resection margins, tumor DNA cell content, and immunoreactivity for p53 and estrogen receptor proteins. Immunostaining for cytokeratin 7 (CK7), cytokeratin 20 (CK20), and gross cystic disease fluid protein-15 (GCDFP) were also performed. Patients were 45 to 82 years of age (mean, 66.9 years). Ten of 21 patients (47.6%) had invasive Paget's disease. Dermal invasion was < or = 1 mm in 7 of 10 cases and 2 mm, 3 mm, and 8 mm in the remaining three invasive tumors. Of the seven patients with minimally invasive Paget's disease (< or = 1 mm depth of invasion), five are alive with no evidence of disease, one died of an unrelated illness, and one is alive with biopsy-proven in situ Paget's disease, having refused operative treatment. Of the three patients with more than minimally invasive Paget's disease (> 1 mm), all had nodal metastases; one patient is alive with no evidence of disease, one died of undertermined causes, and one died of metastatic Paget's disease. The remaining 11 patients had Paget's disease confined to the epidermis and its adnexal structures. Seven of these patients were alive at last follow-up with no evidence of disease. Of the remaining four patients, one died of metastatic cervical cancer, one died of metastatic bladder cancer, one died of an unrelated illness, and one patient is alive with biopsy-proven in situ Paget's disease and awaiting operative treatment. Twenty of the 21 cases represented primary vulvar Paget's disease while one represented possible local spread from a cervical adenocarcinoma. The immunoprofiles were GCDFP+/CK7+/CK20- in 14 cases, GCDFP+/CK7+/CK20+ in 4 cases, and GCDFP-/CK7+/CK20- in 2 cases. All tumors were estrogen receptor-negative. Immunostaining for p53 was positive in 16 tumors and negative in four tumors. Seven of 12 (58%) patients with positive margins experienced local recurrence of Paget's disease, while the disease recurred in 1 of 4 patients with negative margins. Recurrence was observed in 3 of 5 patients with diploid tumors and in 4 of 10 patients with aneuploid tumors. Neither of these differences is statistically significant. This study supports the recognition of a category of minimally invasive vulvar Paget's disease that has a low risk of distant metastasis and death caused by disease. Status of surgical resection margins, tumor cell DNA ploidy, estrogen receptor expression, and p53 immunoreactivity are not predictive of local recurrence.

Aged↗
PubMed1992

Providing shelter for street youth: are we reaching those in need?

A major longitudinal study of runaway and homeless youth resulted in the establishment of a safe house in Calgary. In order to further knowledge building and research in this field, users of the facility are routinely asked to fill out an intake form, and consent is obtained for the use of the information for research purposes. Data collected during the first fourteen months of its operation have now been analyzed. Results are compared to the original survey data to determine which youth are using the facility and which are being missed. Interesting similarities and differences are described and discussed.

Adolescent↗
PubMed1987

Youth on the street: abuse and neglect in the eighties.

This paper discusses the findings of a study of runaways and homeless youth who were interviewed on the street the last week of every month on five week nights from late afternoon until 2 a.m. over a period of one year. The data derived from 489 interviews provided some interesting insights. Two distinct groups emerged from the analysis, generating a tentative hypothesis that the true "runners" tend to leave their homes with the intention of not returning and thus their runs are extended; the second group, designated "in and outers," use the run as a temporary coping mechanism. Their runs tend to be impulsive and of short duration. The study found that runaways (in particular the runners) are at great risk of being drawn into illegal activities. Major factors affecting this risk are distance from home and length of time on the run. A significant proportion of the youth interviewed had run from substitute care arrangements, and a disturbing implication emerging from the research is that adolescents in our society suffer from systemic abuse and neglect. One outcome of this piece of research was the opening of a safe house for early runners in January 1987. The operation of the house includes careful compilation of data to further advance understanding of the runaway population and its needs.

Adolescent↗