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Biomedical subjects

A Mark

Publications and source records attributed to A Mark.

At least 19 recordsLinked to original sources
PubMed2001

Folding study of an Aib-rich peptide in DMSO by molecular dynamics simulations.

To evaluate the ability of molecular dynamics (MD) simulations using atomic force-fields to correctly predict stable folded conformations of a peptide in solution, we show results from MD simulations of the reversible folding of an octapeptide rich in alpha-aminoisobutyric acid (2-amino-2-methyl-propanoic acid, Aib) solvated in di-methyl-sulfoxide (DMSO). This solvent generally prevents the formation of secondary structure, whereas Aib-rich peptides show a high propensity to form secondary structural elements, in particular 3(10)- and alpha-helical structures. Aib is, moreover, achiral, so that Aib-rich peptides can form left- or right-handed helices depending on the overall composition of the peptide, the temperature, and the solvation conditions. This makes the system an interesting case to study the ensembles of peptide conformations as a function of temperature by MD simulation. Simulations involving the folding and unfolding of the peptide were performed starting from two initial structures, a right-handed alpha-helical structure and an extended structure, at three temperatures, 298 K, 340 K, and 380 K, and the results are compared with experimental nuclear magnetic resonance (NMR) data measured at 298 K and 340 K. The simulations generally reproduce the available experimental nuclear Overhauser effect (NOE) data, even when a wide range of conformations is sampled at each temperature. The importance of adequate statistical sampling in order to reliably interpret the experimental data is discussed.

Dimethyl Sulfoxide↗
PubMed2000

Ultrasound-guided fine-needle aspiration and thyroid disease.

BACKGROUND: Fine-needle aspiration represents a critical diagnostic test in determining proper management of thyroid disease and the use of ultrasound-guided fine-needle aspiration (USGFNA) has increased over the years. METHODS: A retrospective chart review of patients undergoing USGFNA. Two hundred fifteen patients underwent 234 procedures with 362 nodules aspirated within a 2 (1/2)-year period. RESULTS: The mean ages of women and men were 51.9 and 57.8, respectively. The average size of nodules was 2.1 cm. A difficult to assess gland or nodule was the most common indication for USGFNA (33%). The sensitivity was 88.2%, specificity was 80.0%, the PPV was 65.2%, the negative predictive value was 94.1%, and the accuracy was 82.5%. The cancer yield, inadequacy, and complication rates were 44%, 10.5%, and 8.5%, respectively. CONCLUSIONS: USGFNA aspiration is a safe and effective diagnostic modality in the management of thyroid disease, especially for nodules that are difficult to palpate.

Biopsy, Needle↗
PubMed2000

Aortic dissection after ingestion of "ecstasy" (MDMA).

The authors report a case of aortic dissection and cardiac tamponade in a 29-year-old man after ingestion of ecstasy (methylenedioxymethamphetamine, MDMA) at a "rave" party. There was no history of hypertension, myxoid heart disease, or other risk factors for aortic dissection in the deceased, although a minor degree of cystic medial necrosis was noted on histologic examination of the aorta. Autopsy toxicology revealed low residual levels of MDMA in the blood about 48 hours after ingestion of the drug. This case report describes a probable association between MDMA ingestion and aortic dissection in a previously well young adult. The likely mechanisms are discussed, and the difficulties in diagnosing this complication are highlighted.

Adult↗
PubMed1999

Subcutaneous versus intramuscular injection for booster DT vaccination of adolescents.

The importance of the injection technique in booster vaccination was investigated in an open randomized study with 252 10-year-old Swedish school-children receiving routine DT vaccination either by subcutaneous or by intramuscular route in the upper arm. The adolescents had previously been primed with DT vaccine at 3, 5 and 12 months of age. Adverse reactions, monitored for 2 weeks, showed the same low rates for systemic reactions in both groups, while the intramuscular administration gave significantly less redness (p < 0.001), swelling (p < 0.001), itching (p < 0.01) and pain (p < 0.05). These reactions were also of shorter duration (p < 0.01 to p < 0.001). Girls were found to have more pain and itching than boys (p < 0.001). No significant differences in antibody responses between the two administration routes were found in the 99 samples drawn 2 weeks after the booster. However, girls were found to have a lower response to diphtheria toxoid than boys (p = 0.009). Local reactions to a booster can thus be significantly reduced by choice of injection technique, which may be necessary if increased dosages and/or further valences are to be given to adolescents and adults.

Antibodies, Bacterial↗
PubMed1998

Food habits in Swedish adolescents in relation to socioeconomic conditions.

OBJECTIVE: To describe the food habits of Swedish adolescents 14-15 y of age. To analyse the connection between food habits and socioeconomic circumstances and background factors. DESIGN: Cross-sectional survey using a Food Frequency Questionnaire including questions on meal patterns. SETTING: The city of Göteborg and the County of Alvsborg, Sweden 1996. SUBJECTS: Pupils in the 8th grade in all schools in the city of Göteborg and the County of Alvsborg were in February 1996 invited to participate. The study comprised 7605 pupils. The drop-out rate was 14.4% (n = 1280). RESULTS: The adolescents had an infrequent consumption of vegetables and fruits and they had a daily consumption of sweets. Cereals, dairy products and snacks: buns, wafers, soft drinks, ice cream and potato crisps were consumed more than once a day. Thirty percent of the girls and 20% of the boys did not eat breakfast every day. The free school lunch was eaten daily by 50% of the boys and 30% of the girls, the remainder ate some type of snack. A negative correlation was found between smoking and the frequency of vegetable consumption. Pupils from areas with high socioeconomic status more often ate breakfast and lunch and the boys more often ate dinner compared to adolescents from areas with low socioeconomic status. CONCLUSIONS: An irregular meal pattern as well as snack consumption and smoking were common, especially among girls in areas with low socioeconomic status.

Adolescent↗
PubMed1998

Chaos and complexity--the future for health care HRM.

The need to understand chaos and complexity in organisations has particular importance for health which is bedevilled by the complexity of organisations and the sometimes chaotic nature of its core activities. This article seeks to explore these issues in the context of one of the key functions which is expected to hold together this diversity: Human Resource Management (HRM). An exploration of the nature of HRM in health care as it has evolved indicates that in order for it to have a pivotal role for the future it will need to rethink this role in the changing paradigm which is now emerging; in so doing it could develop as the organisational intelligence for health care in the future facilitating organisational learning and creativity.

Creativity↗
PubMed1997

A retrospective audit of blood loss in total hip joint replacement surgery at Middlemore Hospital.

AIMS: To quantify the level of inappropriate red cell transfusion in primary and complex hip replacement surgery. METHODS: Data extraction was by retrospective review of patients records. Calculation of total red cell volume loss was by use of pre and postoperative (day 7) haematocrit levels, patient weight and number of units transfused. Transfusion was accepted as justified only if instituted for a 30% red cell volume loss or loss sufficient to drop the haematocrit below 0.28. RESULTS: Of 104 patients having primary hip joint replacement, 58 were transfused with a total of 157 units of red cells; 37 (24%) of these units were given inappropriately. Of 38 patients having complex hip replacement operations, 32 were transfused with a total of 139 units of red cells; 12 (9%) of these were given inappropriately. CONCLUSIONS: Inappropriate transfusion occurs in hip replacement surgery. A concurrent audit of red cell usage is required to better define the magnitude of the problem. Two unit transfusion is commonly given when one unit would have been sufficient.

Blood Loss, Surgical↗
PubMed1997

Immunoglobulin E and G antibodies two years after a booster dose of an aluminium-adsorbed or a fluid DT vaccine in relation to atopy.

Immunoglobulin E and G levels to diphtheria and tetanus toxoids were investigated two years after a DT booster with either an adsorbed or a nonadsorbed, fluid vaccine, given at 10 years of age. Although IgE levels had declined, detectable IgE to diphtheria and tetanus toxoids were still found in 82% and 67% of samples, respectively, to be compared to prebooster levels of 3-14% and postbooster levels of 92-94%. The IgG levels had also declined but remained at equal and high levels in both the adsorbed and the fluid vaccine groups. The prevalence of allergic symptoms was similar in the two vaccination groups. Thus, the study showed an unexpected, long duration of the IgE responses elicited by a booster dose of DT vaccine. The booster dose also induced a durable, high IgG antibody response to both the adsorbed and the fluid vaccine.

Adjuvants, Immunologic↗
PubMed1996

Psychosocial functioning in schoolchildren with recurrent headaches.

The psychosocial functioning of 113 schoolchildren (8 to 15 years old) reporting headaches at least once a month was compared to a group of headache-free control subjects matched for sex and age. Thirteen percent of the headache sufferers had migraine headaches, 28% had episodic tension-type headaches, 30% had chronic tension-type headaches, and 29% had migraine coexisting with tension-type headaches. Overall, the headache sufferers experienced more somatic complaints, stress, and psychological symptoms, in addition to being absent from school (due to illness), more often and reported fewer caring persons as compared to headache-free controls. Although few differences between the four headache groups emerged in the children's psychosocial functioning levels, children with migraine coexisting with tension-type headaches had significantly more frequent somatic complaints than those having episodic tension-type headaches. In addition, children with migraine or migraine coexisting with tension-type headaches were more often absent from school than those having tension-type headaches only. A significant but weak relationship between children's headache severity and their somatic complaints was noted.

Adolescent↗
PubMed1995

Immunoglobulin E responses to diphtheria and tetanus toxoids after booster with aluminium-adsorbed and fluid DT-vaccines.

Immunoglobulin E responses to diphtheria and tetanus toxoids were investigated in pre- and postbooster samples of 104 children given, at 10 years of age, a DT booster with either an adsorbed (n = 51) or a non-adsorbed, fluid vaccine (n = 53). Vaccination with adsorbed DT is part of a national immunisation programme and represents the first regular booster given to these children, primarily immunised with three doses of adsorbed DT at age 3-6 months. The vaccines, with a content of 30 Lf of diphtheria toxoid and 7.5 Lf of tetanus toxoid per millilitre, were given for booster in a dose of 0.25 ml as a deep subcutaneous injection. In the prebooster samples, 3 and 14% had measurable IgE to diphtheria and tetanus, respectively. These rates rose to 94 and 92% in the postbooster samples, respectively. The median (range) of IgE to tetanus among recipients of the adsorbed vaccine was 0.59 PRU ml-1 (< 0.1-17.5), as compared to 0.27 (< 0.1-8.22) in the recipients of the fluid vaccine (p = 0.027). The median IgE response to diphtheria toxoid in the whole group was 1.8 (< 0.1-17.5), with no significant difference between the two vaccines (p = 0.76). There was no correlation between the IgE and IgG responses (r < 0.07, p > 0.5) but the two IgE responses as well as the ratios of IgG/IgE showed strong correlations (r > 0.7, p < 0.001). The study thus revealed unexpectedly high rates of IgE responses to diphtheria and tetanus toxoids in a regular DT booster vaccination programme, which were associated to high rates of local side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1995

Developing the doctor manager: reflecting on the personal costs.

These reflections focus on the development of doctors as managers in the National Health Service and the way that their participation is directly influenced by the personal costs perceived to their professional roles as doctors. Research has indicated some of the problems surrounding the development of doctors as managers. Although training has led to a reduction in stress, women doctors are having to contend with a glass ceiling which is double and even sometimes triple glazed, team development is not being addressed adequately, and succession planning is occurring by default rather than design. The application of domain theory to the issue can provide some guidance for the organisation, but as individual organisations like hospitals interpret these changes in a unique way, it is suggested that the key training for the future will need to focus on transition skills between organisations, and will require interpretive and adaptive responses from both doctors and managers if they are to continue to collaborate successfully in the managerial domain.

Career Mobility↗
PubMed1994

Do special health authority doctors make special managers?

Reviews management training for doctors undertaken in the special health authorities in London. These are postgraduate research institutes in clinical medicine. Compares methodology and outcome issues with the national research programme completed a year earlier, and identifies the context of comparative change between the research programmes. The finds, although similar to the national evaluation the previous year, identify some additions, in particular the lack of formal accountability for the management role in the NHS being undertaken by these university employees, and the differing nature of the working arrangements for these academic doctors who are usually working as knowledge-based networkers across a number of organizations.

Career Mobility↗