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Biomedical subjects

L Morton

Publications and source records attributed to L Morton.

18 recordsLinked to original sources
PubMed2004

Rapid infusion with valproate sodium is well tolerated in patients with epilepsy.

Many IV antiepileptic drugs administered in emergency situations to patients with prolonged seizures have serious adverse effects. For this reason, the authors conducted a multicenter, open-label, prospective, dose-escalation study of IV valproate sodium administered to patients with epilepsy at rates of infusion of up to 6 mg/kg/minute and doses of up to 30 mg/kg. Valproate sodium had no clinically significant negative effects on blood pressure and pulse rate and caused only mild-to-moderate, reversible adverse events.

Acute Disease↗
PubMed2002

Importance of emergency identification schemes.

BACKGROUND: Millions of people worldwide may have a hidden medical condition that could endanger their life in an emergency. These conditions may include cardiac conditions, severe allergies, or diabetes. Emergency identification schemes such as Medic Alert produce emblems that alert health care professionals to potential problems and can ensure appropriate and prompt treatment. This paper uses mechanical failure of the Björk-Shiley convexo-concave (BSCC) heart valve as an example of a hidden medical condition. These patients have been encouraged to carry information to alert staff in an emergency that they have a BSCC patient in their care and to be alert to the signs and symptoms of acute valve malfunction. OBJECTIVE: To establish awareness and credibility of emergency identification schemes among emergency personnel and to assess if information on specific medical conditions would influence ambulance personnel regarding destination hospitals. METHODS: Questionnaires were sent to senior staff (n=380) of accident and emergency (A&E) departments and operational directors of ambulance headquarters (n=39) throughout the United Kingdom. Hospitals were divided into regional divisions to assess differences in responses across regions. RESULTS: The majority of respondents (99%) had heard of emergency identification schemes and felt that it was important for patients with special conditions to carry some form of identification. Nearly all ambulance respondents (97%) indicated it was routine to search for body worn emblems in contrast with only 71% of A & E staff. However, more than half of ambulance respondents (53.9%) stated information on emblems/cards would not influence their choice of destination hospital. CONCLUSIONS: The importance of how information on pre-existing medical conditions can influence care, is highlighted by the BSCC valve issue, where immediate diagnosis is essential for patient survival. It is vital that all staff routinely search patients for this information and if necessary act upon the information provided.

Emergency Medical Services↗
PubMed2001

Normobaric hyperoxic stress in budgerigars: non-enzymic antioxidants.

The effects of oxygen exposure on pulmonary and blood non-enzymic antioxidant concentrations was evaluated in budgerigars (Melopsittacus undulatus). Budgerigars were exposed to acute (3 h), repeated acute (3 exposures each of 3 h) or chronic (72 h) normobaric hyperoxic environments and the pulmonary and plasma concentrations of selected non-enzymic antioxidants, namely glutathione, uric acid, alpha- and gamma-tocopherol and carotenoids were assayed. With increasing duration of oxygen exposure, the ratio of oxidised to reduced glutathione was significantly increased, while the concentrations of uric acid, alpha- and gamma-tocopherol and carotenoids were significantly reduced, especially following chronic oxygen exposure. Following acute and repeated acute exposure, alteration in glutathione concentrations and reduction in alpha-tocopherol concentrations indicated oxygen stress. Following chronic exposure, depletion of non-enzymic antioxidants indicated exhaustion of these protective mechanisms and progression from oxygen stress to oxygen toxicity.

Animals↗
PubMed2000

Incomplete and inaccurate death certification--the impact on research.

BACKGROUND: The objectives of this study were (1) to investigate the extent of erroneous and/or omitted information on death certificates of patients-implanted with Bjork-Shiley Convexo-Concave (BSCC) heart valves; (2) to determine whether this information could be associated with a possible under-reporting of acute mechanical failure of this valve. METHODS: A review was carried out of death certificates and clinical notes for patients implanted in the United Kingdom with BSCC valves. This was a multicentre study (38 hospitals) based at the Cardiothoracic Department, NHLI, Imperial College School of Medicine at Hammersmith Hospital, London. The subjects were 478 patients implanted with a BSCC valve between 1979 and 1986 who died in the following years: 1984, 1987, 1990, 1993 and 1996. The main outcome measures were: (1) percentage of death certificates that record the presence of a valve prosthesis; (2) percentage of death certificates that record the presence of a valve prosthesis for patients who had a post mortem; (3) percentage of death certificates that record inaccurate or incomplete information related to the surgery; (4) percentage of death certificates that do not record a post mortem where one is known to have been performed. RESULTS: Twenty-one per cent (101/478) of the total number of death certificates record the presence of the valve prosthesis. Thirty-five per cent (43/123) of the death certificates for patients who had a post mortem record the presence of a valve prosthesis. Six per cent (30/478) of death certificates report inaccurate information related to the valve surgery. Twenty-five per cent (118/478) of the total number of death certificates recorded a single cause of death. Twenty-three per cent (110/478) of all death certificates reviewed recorded only the mode of dying. Eight per cent (10/123) of the total number of death certificates for patients who had a post mortem did not record a post mortem. CONCLUSIONS: The relatively high number of death certificates that do not record the presence of a valve prosthesis and the observed under-reporting of post mortems may lead to inaccurate reporting of the number of BSCC valves that fail. Previous recommendations to improve accuracy in death certification appear to have gone unheeded, and changes in the way certificates are completed for patients with implanted cardiac devices should be considered.

Aged↗
PubMed1999

Comparison of status epilepticus with prolonged seizure episodes lasting from 10 to 29 minutes.

PURPOSE: Status epilepticus (SE) is a major medical and a neurologic emergency associated with significant morbidity and mortality. The current definition of SE is continuous seizure activity or intermittent seizure activity without regaining consciousness, lasting > or =30 min. Epilepsy monitoring unit data indicate that many seizures self-terminate within minutes. Thus consideration was recently given to include seizure episodes lasting > or =10 min in the definition of SE. Because no large studies have been conducted on seizures lasting 10-29 min, this study was initiated to compare cases of SE and 10 to 29-min seizure episodes seen within the same period. METHODS: Patients seen at the Medical College of Virginia Hospitals of Virginia Commonwealth University over the same 2-year period were studied. Two hundred twenty-six prospective SE cases (91 children and 135 adults) and 81 retrospective 10- to 29-min seizure episodes (31 children and 50 adults) were compared. A standardized data-entry-form system was compiled on each patient and was used to evaluate the data collected. RESULTS: The 10- to 29-min seizure patients and the SE cases had similar demographic characteristics, such as sex, race, and age, and also had similar etiologies. The majority (93%) of SE cases required anticonvulsant (AED) treatment to control and stop seizure activity. In the 10- to 29-min group, 43% stopped seizing spontaneously, and the remainder (57%) required AED treatment to stop seizure activity. The mortality for the SE patients was 19% compared with 2.6% for 10- to 29-min group (p<0.001). In the 10- to 29-min group that stopped seizing spontaneously, the mortality was 0. In the 10- to 29-min patients that required AED treatment, the mortality was 4.4%. CONCLUSIONS: The results demonstrate that a significant number of patients experience seizure activity lasting from 10- to 29-min. Approximately half of these seizure events stopped spontaneously and did not require AED treatment. The other half of the patients responded quickly to medications and stopped seizing before the 30-min definition for SE. The overall mortality of this group was significantly lower than that of the patients with SE. The results demonstrate that further studies on the 10- to 29-min seizure group are needed to differentiate seizures that will stop spontaneously and those that will only stop with AED treatment. Because almost half of the prolonged seizures stopped spontaneously, further studies are needed before including prolonged seizure activity in the definition of SE.

Adult↗
PubMed1996

Clinical characteristics of antiphospholipid antibody syndrome in children.

OBJECTIVE: To evaluate the clinical features and outcome of antiphospholipid syndrome (APS) in children. STUDY DESIGN: Retrospective chart review of patients seen at the Children's Hospital of Philadelphia and Children's Seashore House Pediatric Rheumatology Center between 1988 and 1993. RESULTS: Nine patients with ages ranging from 8 months to 17 years are presented. Clinical features of five patients with primary APS, described in detail, were digital ischemia, stroke, chorea, Addison disease, and pulmonary vaso-occlusive disease. The four children with secondary APS had systemic lupus erythematosus. Clinical features of these patients include livedo reticularis, deep venous thrombosis, and pulmonary hypertension. Antiphospholipid titers, results of coagulation studies, and serologic findings did not predict outcome. CONCLUSION: APS in children has diverse clinical features similar to those in adults and should be considered in cases of unexplained vaso-occlusive disease.

Adolescent↗
PubMed1996

Engineering, expression and renaturation of targeted TGF-beta fusion proteins.

This study reports the expression, purification, and renaturation of biologically active Transforming Growth Factor-beta 1 (TGF-beta 1) fusion proteins from Escherichia coli (E. coli). A prokaryotic expression vector was engineered to produce tripartite fusion proteins consisting of (i) a purification tag, (ii) a protease-sensitive linker/collagen binding domain, and (iii) a cDNA sequence encoding the active fragment of human TGF-beta 1. The expressed fusion proteins TGF-B1-F1 and TGF-B1-F2, located in inclusion bodies, were solubilized with 8 M urea and renatured using a glutathione redox-coupled system and protracted dialysis under several experimental conditions. The purification of the recombinant proteins was achieved by binding the His-tag of the fusion proteins on a Ni-NTA metal chelate column. The biological activity of the recombinant growth factor was demonstrated by its ability to inhibit mink lung (Mv1Lu) cell proliferation and/or to stimulate proliferation of NIH-3T3 mouse fibroblasts, where purified human platelet TGF-beta 1 served as a positive control. Purified TGF-B1-F1 and TGF-B1-F2 (collagen-binding) constructs exhibited anti-proliferative activities comparable to purified platelet TGF-beta 1, but at lower specific activities. Binding of the renatured TGF-B1-F2 fusion protein to collagen was demonstrated by stable binding on a collagen-conjugated Sephadex-G15 column. The high affinity binding was also demonstrated by the binding of 3H-collagen to the TGF-B1-F2 protein immobilized on a Ni-NTA column. The TGF-B1-F2 fusion protein bound to collagen coated surfaces with high affinity but exhibited comparatively lower biological activity than the fusion protein in solution, suggesting a potentially latent configuration. Taken together, these results demonstrate that biologically active TGF-beta 1 fusion proteins can be recovered from transformed bacteria by oxidative refolding; thus, providing a means for its high-yield production, purification, and renaturation from microorganisms. Furthermore, these results support the concept that auxiliary domains may be used to modulate and/or target TGF-beta 1 for specific applications.

3T3 Cells↗
PubMed1995

Childhood growth, physical activity, and peak bone mass in women.

Peak bone mass is an important determinant of the risk of osteoporotic fracture, and preventive strategies against osteoporosis require a clear understanding of the factors influencing bone gain in early life. We report a longitudinal study aiming to identify the relationships between childhood growth, lifestyle, and peak bone mass in women. One hundred and fifty-three women born in a British city during 1968-1969 were traced and studied in 1990. Data on their growth in childhood was obtained from linked birth and school health records; current bone mineral measurements were made by dual X-ray absorptiometry. There were statistically significant associations between weight at 1 year and BMC (but not BMD) at the lumbar spine (r = 0.32, p < 0.01) and femoral neck (r = 0.26, p < 0.01). These remained significant after adjusting for current weight. There were also strong relationships between childhood height measurements and adult BMC at the two skeletal sites. Physical activity was the major lifestyle determinant of BMD after allowing for body build. We conclude that infant growth and physical activity in childhood are important determinants of peak bone mass in women. Growth primarily determines the size of the skeletal envelope, and its trajectory is established by age 1 year. Activity, in contrast, modulates the mineral density within the skeletal envelope and may contribute to the consolidation of bone following the end of linear growth.

Absorptiometry, Photon↗
PubMed1989

Relationship between bile colonization, high-risk factors and postoperative sepsis in patients undergoing biliary tract operations while receiving a prophylactic antibiotic. West of Scotland Surgical Infection Study Group.

A prospective audit of 644 patients undergoing biliary tract operations has been conducted to assess the incidence of bile colonization and its association with the incidence of postoperative sepsis when all patients received the same prophylactic antibiotic. The accuracy of the determination of high-risk factors has been assessed as has the correlation between bile colonization and patients assessed as 'high risk'. Organisms were cultured from the bile of 121 (19 per cent) patients and among these the incidence of wound or intra-abdominal sepsis was 22 per cent whereas among patients with sterile bile the incidence was only 2 per cent (P less than 0.0001). Although the incidence of bile colonization within the high-risk group (32 per cent) was more than twice that in the low-risk group (14 per cent), more than half (54 per cent) of the patients with positive bile cultures were in the low-risk group. It is concluded that, despite prophylactic antibiotics, bile colonization remains the major factor associated with postoperative sepsis, but that this cannot be predicted accurately by preoperative assessment of high-risk factors. Furthermore, we believe that a policy of selective administration of prophylactic antibiotics solely to high-risk patients cannot be justified.

Adult↗
PubMed1987

Stimulation and control as components of stereotyped body rocking.

Severely and profoundly mentally retarded children who engaged in stereotyped body rocking were presented with all possible pairs of three conditions and made a choice as to which they preferred: a rocking chair that rocked freely under the child's control (active stimulation), a rocking chair that provided the same stimulation but was under the experimenter's control (passive stimulation), and a rocking chair that had been immobilized (stationary). Children significantly chose the active stimulation condition over the passive and the passive over the stationary; however, the degree of the effect was associated with developmental level. Results were interpreted as showing that self-stimulation involves at least two independent processes, control and stimulation.

Adolescent↗
PubMed1981

Phenelzine and exposure in the treatment of phobias.

A double-blind study was carried out on 40 agoraphobic and socially phobic patients, matched, then randomly assigned to one of four treatment groups; phenelzine-exposure, phenelzine-no exposure, placebo-exposure, and placebo-no exposure. Exposure consisted of encouraging the patient to face the phobic situation a predetermined number of times. Assessments, made at the beginning and end of 8 weeks of therapy and 8 weeks thereafter, showed that the phobia ratings of groups decreased significantly. The combined exposure group improved significantly more than the combined no exposure group during treatment. At 8 weeks follow-up there was some deterioration in the phenelzine-exposure and placebo-no exposure groups. Exposure, with or without phenelzine, was the superior treatment modality. The antiphobic effect of phenelzine was not supported, although it seemed to reduce subjective anxiety during exposure experiences. The possibility that effect of phenelzine is dose-related is discussed.

Adolescent↗