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Biomedical subjects

B Squires

Publications and source records attributed to B Squires.

11 recordsLinked to original sources
PubMed2001

Fractures of the tuberosity of the calcaneus.

We describe 24 fractures of the tuberosity of the calcaneus in 22 patients. Three were similar to the type of avulsion fracture which has been well-defined but the remainder represent a group which has been unrecognised previously. Using CT and operative findings we have defined the different patterns of fracture of the calcaneal tuberosity. Ten fractures extended into the subtalar joint, but did not fit the pattern of the common intra-articular fracture as described classically. We have defined a new pattern which consists of a fracture of the medial calcaneal process with a further fracture which separates the upper part of the tuberosity in the semicoronal plane. Non-operative treatment of displaced fractures resulted in a mis-shapen heel and a poor functional outcome. Open reduction and internal fixation with either a plate or compression screw did not give satisfactory fixation. We prefer to use an oblique lateral tension-band wire. This technique gave excellent fixation and we recommend it for the treatment of displaced fractures of the tuberosity of the calcaneus.

Adolescent↗
PubMed1999

Displaced intracapsular neck of femur fractures in mobile independent patients: total hip replacement or hemiarthroplasty?

The aim of this study was to compare the outcome of total hip replacement (THR) with hemiarthroplasty in mobile and socially independent patients with displaced intracapsular fractured neck of femur. Thirty-two patients who had been treated by THR were reviewed after a mean of 3.7 years and compared with 42 patients who had been treated by hemiarthroplasty who were reviewed at 3.9 years. At follow-up none of the THRs had required revision whereas 38% of the hemiarthroplasties had required conversion to THR. Six percent of THRs had dislocated. The modified Harris Hip score rated 86% of THRs as 'good' or 'excellent,' whereas only 12% of the remaining hemiarthroplasties achieved a similar rating. Seventy-seven percent of the patients who had received a THR estimated that they could walk more than a mile compared to 27% of the remaining hemiarthroplasties. THR gave a vastly superior functional outcome compared to hemiarthroplasty in this group of patients.

Aged↗
PubMed1997

Effects of CSF-1 on cholesterol accumulation and efflux by macrophages.

To assess whether human monocyte-specific colony-stimulating factor (CSF-1) might influence atherogenesis, CSF-1-induced macrophage responses that might contribute to enhanced clearance of low-density lipoprotein (LDL) or modified LDL were investigated. Careful account was made of cell preservation and increases in cell volume and protein (representing increased cell surface area, and thus endocytically active membrane) during culture with CSF-1. This permitted distinction between selective and nonspecific effects of CSF-1, the latter paralleling increases in cellular mass and volume. CSF-1 enhanced mouse peritoneal macrophage survival in vitro during exposure to lipoprotein-deficient serum with or without native LDL or acetylated LDL (Ac-LDL), as judged by maintenance of cellular DNA and cell numbers. In the presence of copper-oxidized LDL (Ox-LDL), such effects were very slight. In all conditions, CSF-1 increased cellular protein content. CSF-1 increased the uptake of both Ac-LDL and Ox-LDL calculated per culture, but this was entirely explicable by the increased cell protein, indicating that there was no selective enhancement of scavenger receptor or other routes for uptake of the modified LDLs. Similarly, CSF-1 also increased the accumulation of cholesterol and its esters nonspecifically. CSF-1 did have a marked and specific effect on the composition of cholesterol esters, decreasing the proportion of polyunsaturated esters relative to monounsaturated and saturated esters. Finally, cholesterol efflux induced by apolipoprotein A1 from Ac-LDL-loaded macrophages was not influenced by CSF-1. Thus, the enhanced macrophage catabolism of modified LDLs by CSF-1 is part of a nonspecific action on the cells but could contribute to a reduction in circulating cholesterol, observed in some situations of CSF-1 presentation in humans.

Animals↗
PubMed1996

Soft-tissue injuries of the cervical spine. 15-year follow-up.

Forty patients with a whiplash injury who had been reviewed previously 2 and 10 years after injury were assessed again after a mean of 15.5 years by physical examination, pain and psychometric testing. Twenty-eight (70%) continued to complain of symptoms referable to the original accident. Neck pain was the commonest, but low-back pain was present in half. Women and older patients had a worse outcome. Radiating pain was more common in those with severe symptoms. Evidence of psychological disturbance was seen in 52% of patients with symptoms. Between 10 and 15 years after the accident 18% of the patients had improved whereas 28% had deteriorated.

Adult↗
PubMed1995

Exercise stimulus increases ventilation from maximal to supramaximal intensity.

This study investigated the influence of an exercise stimulus on pulmonary ventilation (VE) during severe levels of exercise in a group of ten athletes. The altered ventilation was assessed in relation to its effect on blood gas status, in particular to the incidence and severity of exercise induced hypoxaemia. Direct measurements of arterial blood were made at rest and during the last 15 s of two intense periods of cycling; once at an intensity found to elicit maximal oxygen uptake (VO2max; MAX) and once at an intensity established to require 115% of VO2max (SMAX). Oxygen uptake (VO2) and ventilatory markers were continually recorded during the exercise and respiratory flow-volume loops were measured at rest and during the final 30 s of each minute for both exercise intensities. When compared to MAX exercise, the subjects had higher ventilation and partial pressure of arterial oxygen (PaO2) during the SMAX intensity. Regression analysis for both conditions indicated the levels of PaO2 and oxygen saturation of arterial blood (SaO2) were positively correlated with relative levels of ventilation during exercise. It was apparent that mechanical constraints to ventilate further were not present during the MAX test since the subjects were able to elevate VE during SMAX and attenuate the level of hypoxaemia. This was also confirmed by analysis of the flow volume recordings. These data support the conclusions firstly, that overwhelming mechanical constraints on VE were not present during the MAX exercise, secondly, the subjects exhibiting the most severe hypoxaemia had no consistent relationship with any measure of expiratory flow limitation, and thirdly, ventilatory patterns during intense exercise are strong predictors of blood gas status.

Adolescent↗
PubMed1993

Aerobic and anaerobic indices contributing to track endurance cycling performance.

A group of 18 male high performance track endurance and sprint cyclists were assessed to provide a descriptive training season specific physiological profile, to examine the relationship between selected physiological and anthropometric variables and cycling performance in a 4000-m individual pursuit (IP4000) and to propose a functional model for predicting success in the IP4000. Anthropometric characteristics, absolute and relative measurements of maximal oxygen uptake (VO2max), blood lactate transition thresholds (Thla- and Th(an),i), VO2 kinetics, cycling economy and maximal accumulated oxygen deficit (MAOD) were assessed, with cyclists also performing a IP4000 under competition conditions. Peak post-competition blood lactate concentrations and acid-base values were measured. Although all corresponding indices of Thla- and Th(an),i occurred at significantly different intensities there were high intercorrelations between them (0.51-0.85). There was no significant difference in MAOD when assessed using a 2 or 5 min protocol (61.4 vs 60.2 ml.kg-1, respectively). The highest significant correlations were found among IP4000 and the following: VO2max (ml.kg-2/3.min-1; r = -0.79), power output at lactate threshold (Wthla) (W; r = -0.86), half time of VO2 response whilst cycling at 115% VO2max (s; r = 0.48) and MAOD when assessed using the 5 min protocol (ml.kg-1; r = -0.50). A stepwise multiple regression yielded the following equation, which had an r of 0.86 and a standard error of estimate of 5.7 s: IP4000 (s) = 462.9 - 0.366 x (Wthla) - 0.306 x (MAOD) - 0.438 x (VO2max) where Wthla is in W, MAOD is in ml.kg-1 and VO2max is in ml.kg-1 x min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1993

Needs assessment for reducing infant mortality in Baltimore City: the Healthy Start Program.

Needs assessments are essential for policy formulation and the appropriate design of intervention programs. Recent nationwide data show that among large metropolitan areas of the United States, Baltimore has one of the highest infant mortality rates and ranks in the worst top 10 for blacks and the top 5 for whites for most indicators of poor pregnancy outcome. In this paper, we present the methods and results of a needs assessment that used multiple sources of routinely collected data and was conducted for the purpose of identifying intervention factors contributing to infant mortality in Baltimore City. This needs assessment was used by the Baltimore City Health Department to successfully secure funding for the federal Healthy Start Infant Mortality Prevention Initiative. We present the results of the analyses, along with some of the proposed interventions that resulted from the needs assessment. We also discuss the limitations of this type of needs assessment as well as suggestions for future needs assessments for the design of interventions to improve perinatal health.

Black or African American↗
PubMed1992

Accuracy of pulse oximetry during exercise stress testing.

Pulse oximetry is used extensively during exercise stress-testing in the clinical and sports medicine settings. There are few validation studies to assess the appropriateness of using pulse oximetry under conditions of potentially compromised peripheral blood flow. To study the accuracy of pulse oximetry during severe exercise stress, 10 athletes undertook 3 bouts of exhaustive exercise; once at an intensity requiring VO2max (max), once at 115% of VO2max (Smax), and once at Smax while FIO2 was increased to 0.30. The results indicate relatively large underestimations occur when pulse oximetry is used to estimate %SaO2 during exercise, when compared to the criterion samples of gas analysis in arterial blood. These differences were exacerbated as the exercise intensity increased from a mean(+/- SE) difference of 2.9 +/- 0.7 %SaO2 at max to 4.6 +/- 0.7 %SaO2 at Smax. Breathing a higher FIO2 reversed the hypoxemia that occurred during the normoxic exercise, however, pulse oximetry measurements failed to detect this alteration in %SaO2. Estimates of oxygen saturation during severe exercise using pulse oximetry should be viewed with caution, as potentially large errors may occur.

Adolescent↗