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Biomedical subjects

S J Matthews

Publications and source records attributed to S J Matthews.

At least 37 records · Page 2Linked to original sources
PubMed2000

Nonunion of the femoral diaphysis. The influence of reaming and non-steroidal anti-inflammatory drugs.

We assessed factors which may affect union in 32 patients with nonunion of a fracture of the diaphysis of the femur and 67 comparable patients whose fracture had united. These included gender, age, smoking habit, the use of non-steroidal anti-inflammatory drugs (NSAIDs) the type of fracture (AO classification), soft-tissue injury (open or closed), the type of nail, the mode of locking, reaming nu non-reaming, infection, failure of the implant, distraction at the fracture site, and the time to full weight-bearing. Patients with severe head injuries were excluded. Both groups were comparable with regard to gender, Injury Severity Score and soft-tissue injury. There was no relationship between the rate of union and the type of implant, mode of locking, reaming, distraction or smoking. There were fewer cases of nonunion in more comminuted fractures (type C) and in patients who were able to bear weight early. There was a marked association between nonunion and the use of NSAIDs after injury (p = 0.000001) and delayed healing was noted in patients who took NSAIDs and whose fractures had united.

Adolescent↗
PubMed1999

Stabilisation of acute femoral fractures in Paget's disease.

Eleven cases of acute femoral fractures in patients with Paget's disease are presented following stabilisation with the solid AO femoral nail. In three cases with severe deformity of the femur, reaming was required to enable implant insertion. No corticotomies were required. The median operation time was 55 (35-65) min. There was no operative mortality and no patient developed signs of acute respiratory distress syndrome/fat embolism. Skeletal stability was achieved in all cases. The reconstruction proximal locking option (spiral blade) was utilised in ten of the eleven cases. In all cases a 9 mm nail was inserted. One patient (pagetic sarcoma) died 23 months after surgery. Ten of the eleven fractures healed uneventfully. The mean time to union was 32 (26-42) weeks.

Acute Disease↗
PubMed1999

Exchange nailing for femoral shaft aseptic non-union.

Although rare, non-union of femoral shaft fractures is a cause of significant morbidity. In aseptic non-union, excellent union rates have historically been reported following reamed exchange femoral nailing. However, recently, a high incidence of failure requiring additional procedures has been reported. In light of these concerns and a recent change in our practice to the use of thin solid nails we undertook a retrospective study to determine the efficacy of exchange nailing with these modern nails in our hands. We reviewed records and radiographs of 25 patients who had a reamed exchange femoral nailing for established aseptic non-union. 24 patients (96%) united after exchange without the need for an additional procedure. The mean time to union was 29.75 weeks. Patients who had open bone grafting performed at the same procedure tended to unite quicker, but this did not achieve statistical significance (p = 0.14). Union times were not affected by smoking habits or nail type. This study demonstrates that reamed exchange nailing for aseptic femoral non-union remains an effective treatment. We believe that the nail type is less important than the biological effects of reaming, bone grafting and dynamization.

Adolescent↗
PubMed1998

Some NMR experiments and a structure determination employing a [15N,2H] enriched protein.

We present the results of studies of an aqueous sample of a highly [15N,2H] enriched protein, the SH3 domain from Fyn. Measurements of 1H relaxation and interactions between H2O solvent and exchangeable protons are given, as well as a method for increasing the effective longitudinal relaxation of solvent exchangeable proton resonances. The long-range isotope shifts are measured, for 1H and 15N, which arise due to perdeuteration. Simulations, which employed a 7 or 8 spin relaxation matrix analysis, were compared to the experimental data from a time series of 2D NOESY datasets for some resonances. The agreement between experiment and simulation suggest that, with this 1H dilute sample, relatively long mixing times (up to 1.2 s) can be used to detect specific dipolar interactions between amide protons up to about 7A apart. A set of 155 inter-amide NOEs and 7 side chain NOEs were thus identified in a series of 3D HSQC-NOESY-HSQC experiments. These data, alone and in combination with previously collected restraints, were used to calculate sets of structures using X-PLOR. These results are compared to the available X-ray and NMR structures of the Fyn SH3 domain.

Amides↗
PubMed1998

Challenges in evaluating primary health care for teenagers. Research Sub-Committee of the Adolescent Working Party of the Royal College of General Practitioners, London, UK.

This paper concerns the evaluation of health care for teenagers and examines the role of primary care and its interaction with the teenage users of this service. It recognizes that the majority of health care for teenagers takes place within general practice. The challenge posed is to identify and put in place suitable evaluation tools. There are government targets to improve the health of teenagers by reducing teenage pregnancy, drug use, smoking rates and suicides. It is an assumption of this paper that improvements in experiences of primary care will lead to improvements in more population-based outcomes of care, although this link needs investigation. The paper shows that there are few measures of generic outcome which are available for use in experiments to assess teenage health care as a baseline now. This has implications for conducting future research projects. Such measures are important and it is a necessary feature of research into teenage health that these measures are devised, tested and validated as a priority.

Adolescent↗
PubMed1998

Long-term reduction of renal interstitial hydrostatic pressure after neonatal renin-angiotensin system inhibition in the rat.

BACKGROUND: Neonatal inhibition of the renin angiotensin system (RAS) causes a decreased urinary concentrating ability, papillary atrophy, and tubulointerstitial inflammation long term. As a consequence of these morphological changes, we surmised that renal blood flow and renal interstitial hydrostatic pressure (RIHP) may be altered during and shortly after cessation of neonatal angiotensin-converting enzyme (ACE) inhibition, and that tentative changes of these variables would persist long after treatment withdrawal. METHODS: Rats were given daily intraperitoneal injections of the ACE inhibitor, enalapril (10 mg/kg) or saline from days 3 to 23 postpartum, and the relationship between renal perfusion pressure (PP) and RIHP was investigated in 6- and 13-week-old anaesthetized rats. RESULTS: Neonatal ACE inhibition did not affect baseline RIHP short term, whereas RIHP was reduced at 13 weeks of age versus controls (11.6+/-1.6 vs 18.5+/-1.0 mmHg, P<0.05). Changes in RIHP correlated positively to changes in renal PP, independent of treatment and age (slope averaged 0.11+/-0.03). Ongoing ACE inhibition until 6 weeks of age neither affected baseline RIHP nor altered the reactivity to changes in perfusion pressure. Mild renal histopathological abnormalities were present already 3 weeks after cessation of treatment and were aggravated significantly in the 13-week-old rats, showing a complete loss of the papillary parenchyma. CONCLUSION: The reduced baseline RIHP in adult rats seemed to constitute a functional correlate to the major papillary atrophy. However, RIHP responses to changes in renal perfusion pressure was maintained, possibly indicating a compensatory effect of the remaining vasa recta and/or peritubular capillary network. Taken together, lack of neonatal angiotensin II type-1 (AT1) receptor stimulation induces not only irreversible abnormalities of the renal architecture, but causes alteration of intrarenal haemodynamics, such as a reduced RIHP, which may have implications for the regulation of pressure-natriuresis.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Nutritional regulation of insulin-like growth factor-I mRNA expression in barramundi, Lates calcarifer.

The effect of nutritional status on IGF-I mRNA expression in the liver and brain of juvenile barramundi (Lates calcarifer) was investigated. Fish were either fed a satiety ration (SAT) or starved (STV) for 6 weeks. Starved fish demonstrated significantly lower condition factor and hepatic IGF-I mRNA expression at 3 and 6 weeks, when compared with the SAT group. IGF-I mRNA expression in the brain was 10 fold lower than the liver and was not affected by ration size. These results suggest the liver is the major site of IGF-I mRNA synthesis and hepatic but not brain IGF-I mRNA expression is regulated by food availability in juvenile barramundi.

Animals↗
PubMed1994

The acetabular notch in hip dysplasia.

In the first few months of life, a notch may be seen on radiographs of the superolateral margin of the infant hip. It may be associated with a steeply inclined acetabular roof and may be an indicator of persistent neonatal instability or displacement of the femoral head.

Acetabulum↗
PubMed1993

13C NMR study of the effects of mutation on the tryptophan dynamics in chymotrypsin inhibitor 2: correlations with structure and stability.

Recombinant chymotrypsin inhibitor 2 (CI-2) and the three mutants Ile39-->Val, Ile39-->Leu, and Arg67-->Ala were successfully enriched with [2-13C]tryptophan at position 24 within the hydrophobic core of the protein. Carbon-13 NMR relaxation measurements were then used to investigate the effect of these mutations on the dynamics of the tryptophan residue. In addition, the stability of wild-type and mutant CI-2s was measured by their susceptibility to unfolding by guanidine hydrochloride. The mutant proteins were all found to be less stable, giving delta delta GU values relative to wild-type of 1.17, 1.96, and 1.21 kcal mol-1, respectively. The indole moiety of the tryptophan residue was found to be more mobile in all the mutants studied than in wild-type CI-2. Order parameters of 0.69, 0.60, 0.56, and 0.44 were derived for wild-type, Ile39-->Val, Ile39-->Leu, and Arg67-->Ala CI-2, respectively. It is concluded that there is a correlation between the protein stability and the picosecond dynamics within the hydrophobic core and that mutations can influence the dynamic behavior of the residues that are relatively distant in the three-dimensional structure.

Base Sequence↗
PubMed1992

A role for tumour necrosis factor-alpha in the human mixed lymphocyte culture reaction.

The possible role and influence of tumour necrosis factor-alpha (TNF-alpha) in the human mixed lymphocyte culture (MLC) reaction was investigated. Polyclonal rabbit sera to recombinant human-TNF-alpha (rhTNF-alpha) consistently inhibited the MLC, and this could be reversed by simultaneous addition of rhTNF-alpha to the culture medium. Under optimal cell culture conditions, the exogenous addition of 1000 U/mL of rh TNF-alpha had a variable but generally small enhancing effect on the MLC reaction. Additional studies have clearly highlighted the importance of MLC assay conditions in influencing the effect of exogenous rhTNF-alpha. Enhancement of the MLC reaction was only consistently observed under suboptimal cell culture conditions. While the present study clearly supports an important role for TNF in controlling the proliferative response in the human MLC reaction it also highlights the influence of in vitro tissue culture conditions in determining the effect of exogenous TNF-alpha in this assay.

Humans↗
PubMed1992

DUE of ciprofloxacin in the treatment of urinary tract infections in hospitalized patients.

In this retrospective study of 30 patients with urinary tract infections, a drug usage evaluation indicated that 60% of the patient population sampled were appropriately switched to ciprofloxacin from IV antimicrobial agents; inappropriate use was identified in 40%. The drug's safety profile indicates that patients can be safely removed from IV antimicrobial therapy and continue treatment on ciprofloxacin, a measure which reduces treatment costs. These costs also can be lowered when inappropriate ciprofloxacin use is ruled out in patients with organisms sensitive to less costly oral antimicrobials. Identifying which patients should be removed from parenteral therapy maximizes the economic benefit of ciprofloxacin therapy and optimizes the impact of pharmacy intervention on patient care.

Adult↗
PubMed1991

Anterior cruciate ligament reconstruction using the Gore-tex ligament.

Twenty two Army patients with synthetic (Gore-tex) anterior cruciate ligament (ACL) reconstructions were reviewed (mean follow up 18 months). Reconstruction appeared to abolish the pivot shift sign in all cases, but some subjective instability persisted in all but 6 patients. Outcome was also assessed by medical (PULHHEEMS) grading: 6 patients were fully fit (graded L2), 7 returned to moderate activity but not full fitness (L3), and 9 remained severely incapacitated (L7 or L8) with 4 of this group being medically discharged. Specific operative complications included: prosthesis breakage (3 partial, 1 complete), infected prosthesis(1), and problems with the tibial screw(3). The range and frequency of complications was similar in other series. Physical fitness is an integral part of a soldier's job, placing particular demands on the knee and on surgical repair of knee injuries. Reports on the Gore-tex ACL prosthesis in other groups have been more encouraging, but there are difficulties in comparing this study with others. ACL insufficiency remains a serious problem, with implications for a soldier's fitness and career. The Gore-tex prosthesis improves stability but does not always allow a soldier to return to full fitness.

Adult↗