bluuebunny/crossref_metadata_2025 huggingface dataset:
Gamma‐glutamyl transpeptidase and the metabolic syndrome
Authors: Rantala A. O. , Lilja M. , Kauma H. , Savolainen M. J. , Reunanen A. , Kesäniemi Y. A.
Published: March 2003

Abstract. Rantala AO, Lilja M, Kauma H, Savolainen MJ, Reunanen A, Kesäniemi YA (University of Oulu, Oulu; and The National Public Health Institute, Helsinki, Finland). Gamma‐glutamyl transpeptidase and the metabolic syndrome. J Intern Med 2000; 248: 230–238.

Objective. To analyse the associations between serum gamma‐glutamyl transpeptidase activity (GTP) and the components of the metabolic syndrome.

Design. Cross‐sectional, observational study of hypertensive patients and controls.

Setting. The participating subjects visited the research laboratory of the Department of Internal Medicine, University of Oulu, Oulu, Finland.

Subjects. A total of 1045 Caucasians, 40–59 years of age, consisting of 261 drug‐treated hypertensive men, 258 drug‐treated hypertensive women and 526 age‐ and sex‐matched controls.

Main outcome measures. The associations between GTP and the cardiovascular risk factors were analysed through multiple regression and logistic methods and by GTP tertiles. The independent effect of GTP on different insulin measures, calculated from the values of 2 h of oral glucose tolerance test, was estimated after concurrent adjustment for age, obesity and alcohol consumption.

Results. GTP correlated highly significantly with the components of the metabolic syndrome. The correlation coefficient were 0.33 between GTP and body mass index, 0.25 between GTP and systolic blood pressure in control men (P = 0.0001), 0.39 between GTP and triglycerides, and 0.32 between GTP and fasting insulin in hypertensive women (P = 0.0001). The association between GTP and blood pressure remained significant only at upright measurements in controls. All insulin measures had a significant positive association with increasing GTP tertiles in all the study groups (e.g. fasting insulin 8.1 mU L–1 in the lowest and 11.0 mU L–1in the highest tertile in control women, P = 0.0001), with the exception of fasting insulin in control men. In a pooled logistic analysis after adjustment for age, body mass index, alcohol consumption and gender, the independent predictors of the metabolic syndrome were body mass index, uric acid, total cholesterol and GTP (for log‐transformed GTP odds ratio 4.0, 95% CI: 2.80–5.69).

Conclusions. There are significant associations between GTP and the components of the metabolic syndrome. Elevated levels of GTP may not always indicate increased alcohol consumption, but may also suggest the existence of the metabolic syndrome with its subsequent deleterious consequences.
Are patients truthful about their smoking habits? A validation of self‐report about smoking cessation with biochemical markers of smoking activity amongst patients with ischaemic heart disease
Authors: From Attebring M. , Herlitz J. , Berndt A.‐K. , Karlsson T. , Hjalmarson A.
Published: March 2003

Abstract. From Attebring M, Herlitz J, Berndt A‐K, Karlsson T, Hjalmarson A (Division of Cardiology, Sahlgrenska University Hospital, Göteborg, Sweden). Are patients truthful about their smoking habits? A validation of self‐report about smoking cessation with biochemical markers of smoking activity amongst patients with ischaemic heart disease. J Intern Med 2001; 249: 145–151.

Aim. To validate self‐report about smoking cessation with biochemical markers of smoking activity amongst patients with ischaemic heart disease.

Patients and methods. Outpatients at the Division of Cardiology, 75 years of age or younger, who had been Hospitalized at Sahlgrenska University Hospital in Göteborg due to an ischaemic event and who consecutively participated in a nurse‐monitored routine care programme for secondary prevention, from 6 February 1997 to 5 February 1998. Data concerning smoking habits were collected through interviews. Two chemical markers, cotinine in plasma and carbon monoxide (CO) in expired air, validated self‐reports concerning smoking cessation.

Results. 260 former smokers were validated. In the vast majority of the study population, the anamnestic information concurred with the chemical marker. However, 17 patients had chemical markers that contradicted their self‐report with raised CO (n = 6) and/or raised cotinine levels (n = 13) without alternative nicotine delivery.

Conclusion. Most patients with coronary artery disease relating information concerning cessation of smoking are truthful. A few patients, however, seem to conceal their smoking. Testing by chemical markers may be questionable for ordinary care but should, however, be included in studies concerning the association between smoking and health.
Effect of plant sterol‐enriched margarine on plasma lipids and sterols in subjects heterozygous for phytosterolaemia
Authors: Stalenhoef A. F. H. , Hectors M. , Demacker P. N. M.
Published: March 2003

Abstract. Stalenhoef AFH, Hectors M, Demacker PNM (University Medical Centre Nijmegen, Nijmegen, The Netherlands). Effect of plant sterol‐enriched margarine on plasma lipids and sterols in subjects heterozygous for phytosterolaemia. J Intern Med 2001; 249: 163–166.

Objective. Margarine with added plant sterols lowers plasma cholesterol levels. It is of importance to know whether these margarines can be used safely in carriers of a hereditary disorder with increased absorption of plant sterols.

Design. In an open feeding study of 8 weeks with a 2‐week run‐in period and 2 final weeks as a washout period on control margarine (0.3% plant sterols), two obligate heterozygous parents of a patient with classical sitosterolaemia were subjected for 4 weeks to a diet containing margarine enriched with plant sterols (8%). Fasting blood samples were taken weekly. Primary outcomes were plasma lipid and lipoprotein levels and plant sterol levels.

Results. Both parents were hyperlipidaemic. Total plasma cholesterol levels were decreased by 11 and 12%, respectively, after 4 weeks of the consumption of 40 g day−1 of plant sterol‐enriched margarine. This was mainly due to changes in LDL‐cholesterol, whereas the other lipoproteins, including lipoprotein(a), were unaffected. Total plant sterol levels increased maximally 139% from 0.31 to 0.82% of total sterols in the father, and maximally 83% from 0.32 to 0.66% of total sterols in the mother.

Conclusion. An intake of around 3 g day−1 of plant sterols by subjects heterozygous for phytosterolaemia increased campesterol or sitosterol levels in blood to similar levels as found in normal subjects. In addition, plasma cholesterol levels were reduced to the same extent as in normal or hypercholesterolaemic individuals.
Clinical outcome of patients with suspected pulmonary embolism. A follow‐up study of 588 consecutive patients
Authors: Poulsen S. Hvitfeldt , Noer I. , Møller J. E. , Knudsen T. E. , Frandsen J. Lundbye
Published: March 2003

Abstract. Poulsen SH, Noer I, Møller JE, Knudsen TE, Frandsen JL (Randers Hospital and Svendborg Hospital, Denmark). Clinical outcome of patients with suspected pulmonary embolism. A follow‐up study of 588 consecutive patients. J Intern Med 2001; 250: 137–143.

Objective. To investigate the clinical outcome in patients with clinically suspected pulmonary embolism (PE).

Design and setting. In a retrospective design we studied 588 consecutive patients with suspected PE and referred for lung scintigraphy from 1995 to 1998. The mean follow‐up time was 653 ± 424 days.

Results. The diagnosis of PE was confirmed in 194 and excluded in 394 patients, respectively. The overall prevalence of PE was 33%. Amongst clinical and paraclinical variables, age, chronic obstructive pulmonary disease (COPD), heart rate, pleuretic pain, presence of deep venous thrombosis (DVT), electrocardiographic signs of right ventricular (RV) strain were identified as independent predictors of the diagnosis of PE. Amongst patients with PE anticoagulation was given in 96% for at least 3 months and 13% received thrombolytic therapy. Recurrent PE was seen in 6% of patients with PE whereas none of the patients with no diagnosis of PE suffered PE during follow‐up. The 1 year mortality was 18% amongst patients with PE and 15% in patients with excluded PE (P=NS). The cause of death amongst patients with PE was cancer (49%) and PE (28%), whereas patients without PE had an excess mortality because of cancer, COPD, acute myocardial infarction and heart failure.

Conclusion. Patients admitted to hospital on suspicion of PE have increased risk of adverse clinical outcome whether the diagnosis of PE is confirmed or not. This indicates that the patients where the diagnosis is excluded often suffer from other serious illness that warrants further investigations.
Consequences of late referral of patients with end‐stage renal disease
Authors: Gøransson L. G. , Bergrem H.
Published: March 2003

Abstract. Gøransson LG, Bergrem H (Central Hospital of Rogaland, Stavanger, Norway). Consequences of late referral of patients with end‐stage renal disease. J Intern Med 2001; 250: 154–159.

Objectives. The aim of the present retrospective single centre study of patients entering renal replacement therapy (RRT), was to evaluate the effects of different referral patterns on morbidity, choice of therapy, and duration of hospitalization in patients with chronic renal failure.

Subjects. A total of 242 patients with chronic renal failure starting their first RRT between 1984 and 1998, were divided into three groups. Group 1 (n=80): RRT started 1984–88, group 2 (n=73): RRT started 1989–93 and group 3 (n=89): RRT started 1994–98. Patients were classified as early referrals (ER) or late referrals (LR) depending on whether they started first RRT more than or less than 3 months after first referral to a nephrologist.

Results. The proportion of LR was 27.3% (21 patients) in group 1, 27.4% (20 patients) in group 2 and 28.1% (25 patients) in group 3. In the ER, 35 patients (14.5%) received a predialytic kidney transplant, none in the LR. Comparing clinical details, the LR’s in group 3 were significantly older than ER [median age 72 (53–81) vs. 56 (15–81) years, P < 0.0001], had a lower serum‐albumin [median 33.0 (19.0–42.0) vs. 39 (19.0–48.0) g L−1, P < 0.0001], and serum‐calcium [median 2.0 (1.4–2.6) vs. 2.3 (1.8–2.7) mmol L−1, P < 0.0001]. The ER had a significantly higher use of antihypertensive drugs, calcitriol, phosphate binders, and bicarbonate. Of the patients starting RRT on haemodialysis, all LR started on a temporary vascular access. About 43% of the ER started on a functioning arteriovenous fistula (P < 0.0001). The duration of hospital stay in connection with start of dialysis was 31 days (7–73) in the LR as compared with 7 (1–59) days in the ER (P < 0.0001).

Conclusions. We conclude that in our centre, early referral to nephrologist is associated with lower age, a higher likelihood of predialytic transplantation, better metabolic status at start of RRT, a higher proportion starting haemodialysis on a functioning arteriovenous fistula, and a shorter duration of the initial hospital stay. Further research on health care delivery is warranted.
Hospitalizations for atrial fibrillation in the general male population: morbidity and risk factors
Authors: Wilhelmsen L. , Rosengren A. , Lappas G.
Published: March 2003

Abstract. Wilhelmsen L, Rosengren A, Lappas G (Göteborg University, Göteborg, Sweden). Hospitalizations for atrial fibrillation in the general male population: morbidity and risk factors.J Intern Med2001;250: 382–389.

Objectives. To analyse the incidence, prevalence, aetiology, risk factors and prognosis of hospitalizations for atrial fibrillation.

Subjects. A random population sample of 7495 men aged 47–55 years was first examined in 1970–73. During follow‐up until 1996 (mean 25.2 years) 754 men were hospitalized with a diagnosis of atrial fibrillation.

Results. In the age groups of 55–64, 65–74 and 75–79 years, the incidence rate was 2.0, 5.8 and 17.3 per 1000 person years, and the prevalence 1.2, 4.2 and 8.0%, respectively. Definite or possible coronary heart disease was diagnosed in 46.0%, heart failure in further 20.2% and valvular heart disease or cardiomyopathy in 4.5%. In bivariate analysis adjusted for age, the following factors were significantly associated with future hospitalization for fibrillation: a family history of myocardial infarction, stroke in mother, dyspnoea at entry, alcohol abuse, high body stature and body weight, high blood pressure but not diabetes, high serum cholesterol, high heart rate, smoking, coffee consumption or psychological stress. Significant risk factors in multivariate analysis were age, odds ratio (OR) [95% confidence interval (CI)] – 1.11 (1.07, 1.16) per year, hospitalization for coronary heart disease or heart failure – 6.77 (5.17, 8.87), stroke in mother – 1.49 (1.15, 1.93), high body stature – 1.04 (1.03, 1.06) per cm, high body mass index (BMI) – 1.07 (1.04, 1.10) per kg m–2, as well as hypertension – 1.33 (1.07, 1.65). After a diagnosis of atrial fibrillation, mortality was increased by 3.3 times.

Conclusion. In spite of a clinical association with coronary heart disease, risk factors for atrial fibrillation were only partly the same. Prevention includes avoidance of weight gain and control of blood pressure as well as prevention of myocardial infarction and heart failure.
Acute and chronic neutropenias. What is new?
Authors: Palmblad J. , Papadaki H. A. , Eliopoulos G.
Published: March 2003

Abstract. Palmblad J, Papadaki HA, Eliopoulos G (The Karolinska Institute at Huddinge University Hospital, Stockholm, Sweden and University of Crete Medical School, Heraklion, Greece). Acute and chronic neutropenias. What is new?J Intern Med2001;250:476–491.

Recently, some of the mechanisms and consequences in the severe chronic neutropenias (e.g. the neutrophil elastase gene mutations and the risk to progress to myelodysplasia and acute leukaemia) and in drug‐induced agranulocytosis (e.g. the apoptosis‐inducing ability of metabolites of clozapine) have been elucidated, and new aspects of autoimmune and the large granular lymphocyte syndrome were described (e.g. aberrant elaboration of Fas‐ligand causing neutrophil apoptosis). Investigations of the mild to moderate chronic neutropenias have shown the significance of interactions between the myeloid development and the immune network (e.g. relations to immunoglobulin aberrations). Granulocyte‐colony stimulation factor (G‐CSF) is widely used in patients with severe chronic neutropenia, however, its use in other conditions is mostly based on anecdotal evidence. In addition, immune modulating regimens, such as metothrexate, ciclosporine and monoclonal antibodies, are increasingly employed for the autoimmune neutropenias.
Specific bronchoalveolar lavage fluid T cells associate with disease in a pair of monozygotic twins discordant for sarcoidosis
Authors: Grunewald J. , Eklund A.
Published: March 2003

Abstract. Grunewald J, Eklund A (Karolinska Hospital, Stockholm, Sweden). Specific bronchoalveolar lavage fluid T cells associate with disease in a pair of monozygotic twins discordant for sarcoidosis (Case report). J Intern Med 2001; 250: 535–539.

A 49‐year‐old Caucasian woman had an acute onset of sarcoidosis. Bronchoscopy with bronchoalveolar lavage (BAL) showed a pronounced accumulation of BAL fluid CD4+ T cells expressing the T‐cell receptor (TCR) AV2S3 gene. In line with this observation, the patient was HLA‐DR17 positive, previously shown to strongly correlate with lung compartmentalized AV2S3+ T cells. At follow‐up after recovery, reduced numbers of BAL fluid AV2S3+ T cells were found. Interestingly, BAL fluid of a healthy monozygotic twin sister contained normal numbers of AV2S3+ lung T cells. This report shows the T‐cell repertoire of BAL fluid T cells to correlate with the disease (sarcoidosis), indicating a local and specific immune response triggered by an unknown antigen in sarcoidosis.
Oxidative stress and antioxidant status in type 1 diabetes mellitus
Authors: VESSBY J. , BASU S. , MOHSEN R. , BERNE C. , VESSBY B.
Published: March 2003

Abstract. Vessby J, Basu S, Mohsen R, Berne C, Vessby B (Section for Clinical Nutrition Research, Department of Public and Caring Sciences; and Department of Internal Medicine, Uppsala University, Uppsala, Sweden). Oxidative stress and antioxidant status in type 1 diabetes mellitus. J Intern Med 2002; 251: 69–76.

Objectives. To test the hypothesis that type 1 diabetes is associated with increased oxidative stress and/or antioxidant status by investigating concentrations of 8‐iso‐prostaglandin F2α (8‐iso‐PGF2α) in urine and plasma and malondialdehyde (MDA) in plasma as indicators of lipid peroxidation in vivo, and antioxidant status in diabetic subjects compared with healthy control subjects.

Design and subjects. Thirty‐eight subjects with type 1 diabetes mellitus and 41 healthy age‐ and sex‐matched control subjects were included in the study. Blood and urine samples were obtained and analysed for 8‐iso‐PGF2α with a newly developed radioimmunoassay, as well as for MDA, total antioxidant capacity (TAOC) and serum tocopherol levels.

Results. None of the variables of lipid peroxidation showed any significant difference between the two groups. Similarly, there were no significant correlations between the levels of 8‐iso‐PGF2α or MDA, and degree of glycemic control (HbA1c). Total antioxidant capacity in plasma was 16% lower amongst the subjects with type 1 diabetes than in the control group (P < 0.0005). Lipid corrected levels of α‐tocopherol in serum were significantly increased in type 1 diabetic subjects (P < 0.05), as were γ‐tocopherol levels (P < 0.005).

Conclusions. In spite of lower total antioxidant defence, our results do not support the oxidative stress hypothesis for type 1 diabetes mellitus. The higher tocopherol levels suggest that no vitamin E supplementation is necessary for subjects with type 1 diabetes mellitus.
Unusual case of a large midoesophageal diverticulum mimicking unstable angina pectoris
Authors: HOFFMANN J. C. , PISTORIUS G. , MÜLLER P. , ZEITZ M.
Published: March 2003

Abstract. Hoffmann JC, Pistorius G, Müller P, Zeitz M (Universitätskliniken des Saarlandes, Homburg/Saar, Germany). Unusual case of a large midoesophageal diverticulum mimicking unstable angina pectoris (Case report). J Intern Med 2002; 251: 355–360.

We describe a 77‐year‐old lady who presented with progressive retrosternal pain radiating to the left arm and the back. After exclusion of cardiac causes a large midoesophageal diverticulum was found on oesophago‐gastro‐duodenoscopy. Importantly, the retrosternal pain completely disappeared after endoscopic removal of impacted food from the diverticulum. After the surgical resection the patient became fully asymptomatic. This is the first example of angina‐like chest pain which definitively resulted from a midoesophageal diverticulum. Therefore, midoesophageal diverticula should be considered as a rare differential diagnosis of exercise‐induced retrosternal pain.
Thyroid dysfunction during treatment of chronic hepatitis C with interferon alpha: no association with either interferon dosage or efficacy of therapy
Authors: DALGARD O. , BJØRO K. , HELLUM K. , MYRVANG B. , BJØRO T. , HAUG E. , BELL H.
Published: March 2003

Abstract. Dalgard O, Bjøro K, Hellum K, Myrvang B, Bjøro T, Haug E, Bell H (Aker University Hospital, Oslo; National Hospital, Oslo; Akershus Central Hospital, Nordbyhagen; and Ullevål University Hospital, Oslo, Norway). Thyroid dysfunction during treatment of chronic hepatitis C with interferon alpha: no association with either interferon dosage or efficacy of therapy. J Intern Med 2002; 251: 400–406.

Objectives. Treatment of chronic hepatitis C with interferon‐α (IFN‐α) may induce thyroid disorders. We evaluated whether this risk is related to the dosage of IFN‐α or the virological treatment response. Other possible risk factors as well as the evolution of the thyroid abnormalities were also studied.

Methods. In this prospective trial (n=254), thyroid‐stimulating hormone (TSH), free thyroxin (fT4) and thyroid peroxidase autoantibodies were measured before, during and after treatment for hepatitis C virus (HCV). The patients were randomized to either induction therapy [IFN‐α 6 million units (MIU) daily for 4 weeks and 3 MIU 3/7 days for 22 weeks] or conventional therapy [IFN‐α 3 MIU 3/7 days for 26 weeks]. In addition, all patients received ribavirin (1000 or 1200 mg) daily. Sustained virological response was defined as loss of detectable HCV RNA at 6 months follow‐up. Thyroid dysfunction was defined as TSH level below or above the normal range (0.2–4.5 MIU L−1).

Results. Biochemical thyroid dysfunction developed in 30 (11.8%) of 254 patients. Hypothyroidism (TSH > 4.5 MIU L−1) was seen in 20 and hyperthyroidism (TSH < 0.2 MIU L−1) in 10 patients. Nine of the 30 patients developed symptomatic thyroid disease and HCV treatment was discontinued because of thyroid dysfunction in three of these patients. Thyroid dysfunction occurred in 15 (11.7%) of 128 patients who received high‐dose IFN‐α induction therapy as compared with 15 (11.9%) of 126 patients who received conventional IFN‐α therapy (P=0.96). Amongst 231 patients who completed all 6 months of HCV treatment, a sustained virological response was obtained in 19 (66%) of 29 with thyroid dysfunction and 109 (54%) of 202 without (P=0.24). By multivariate analysis female gender and Asian origin were independent predictors of developing biochemical thyroid dysfunction (P < 0.01).

Conclusion. Thyroid dysfunction occurred in 11.8% of patients treated for chronic hepatitis C with IFN‐α and ribavirin. Neither the IFN‐α dosage nor the virological response to treatment were related to the incidence of thyroid dysfunction.
Dyspeptic symptoms in middle‐aged to old adults: the role of Helicobacter pylori infection, and various demographic and lifestyle factors
Authors: BODE G. , BRENNER H. , ADLER G. , ROTHENBACHER D.
Published: March 2003

Abstract. Bode G, Brenner H, Adler G, Rothenbacher D. (University of Ulm and University of Heidelberg, Germany). Dyspeptic symptoms in middle‐aged to old adults: the role of Helicobacter pylori infection, and various demographic and lifestyle factors. J Intern Med 2002; 252: 41–47.

Objectives To evaluate the role of factors supposed to interfere with the gastric mucosa like Helicobacter pylori, smoking and analgesics in symptom generation in a population‐based sample of middle‐aged to old.

Subjects A total of 288 subjects aged 50–85 (mean 65 ± 7.2) attending a General Science‐orientated Continuing Education Programme at the University of Ulm.

Methods Helicobacter pylori infection was determined by the 13C‐urea breath test. Demographic data, gastrointestinal symptoms and factors supposed to be involved in symptom generation were collected by a standardized questionnaire. The association between various demographic and lifestyle factors with a gastrointestinal symptom score was quantified by odds ratios (ORs) using multiple logistic regression.

Results Use of nonsteroidal anti‐inflammatory drugs (OR=1.2; 95% CI=0.7–2.1) was no risk factor for abdominal symptoms, whereas female sex (OR= 1.6; 95% CI=0.9–2.9) and current smoking (OR= 3.7; 95% CI=0.9–15.4) were associated with a high symptom score. Age 70 years and over was significantly associated with a lower symptom score (OR=0.4; 95% CI=0.2–0.9). However, H. pylori infection was a risk factor for a high symptom score in that age group (OR=4.3; 95% CI=1.2–14.8), whereas no such association (and even a tendency to reduced symptom levels in infected subjects) was observed in younger age groups.

Conclusion The role of H. pylori infection in symptoms may vary by age. The loss of symptoms in the elderly may delay detection of gastroduodenal pathology and appropriate treatment in older adults.
Enterovirus, mycoplasma and other infections as predictors for myocardial infarction
Authors: Reunanen A. , Roivainen M. , Kleemola M. , Saikku P. , Leinonen M. , Hovi T. , Knekt P. , Leino A. , Aromaa A.
Published: March 2003

Abstract. Reunanen A, Roivainen M, Kleemola M, Saikku P, Leinonen M, Hovi T, Knekt P, Leino A, Aromaa A (National Public Health Institute, Helsinki and Oulu; Social Insurance Institution, Turku; University Hospital, Turku, Finland). Enterovirus, mycoplasma and other infections as predictors for myocardial infarction. Journal of Intern Med 2002; 252: 421–429.

Objectives. To study antibodies against five infectious agents for their prediction of major coronary events in men with and without evidence of coronary heart disease at baseline.

Design. A case–control study nested within a prospective population study.

Subjects. The study cases included 441 men 45–64 years old with nonfatal myocardial infarction or coronary death within a mean follow‐up time of 10 years. A total of 165 men had already signs of heart disease at baseline, whilst 276 were apparently healthy at the beginning of the study. Two controls for each case were matched for age, heart disease status and place of residence. Antibodies against enterovirus, Mycoplasma pneumoniae, Chlamydia pneumoniae, cytomegalovirus and adenovirus were determined.

Results. Men without reported baseline heart disease, but not those with heart disease, showing the highest quartile of antibodies to enterovirus and mycoplasma or increased levels of immune complex‐bound antibodies to chlamydia had a significantly higher risk of coronary events than men with lower level of antibodies. The increased risk demonstrated in men with high levels of antibodies to enterovirus and mycoplasma remained significant after adjustment for other antibodies, acute‐phase reactant and conventional risk factors. Serological evidence of infection by multiple agents was also significantly associated with coronary events.

Conclusions. Serological evidence for several infectious agents is associated with the risk of coronary heart disease, but only in men without baseline history of heart disease.
Acquired platelet dysfunction may be an aetiologic factor in Heyde's syndrome – normalization of bleeding time after aortic valve replacement
Authors: Olsson M. , Hultcrantz R. , Schulman S. , Wallgren E.
Published: March 2003

Abstract.  Olsson M, Hultcrantz R, Schulman S, Wallgren E (Karolinska Hospital, Karolinska Institute, Stockholm Institute, Stockholm, Sweden). Acquired platelet dysfunction may be an aetiologic factor in Heyde's syndrome – normalization of bleeding time after aortic valve replacement. J Intern Med 2002; 252: 516–523.

Background.  There is a well‐documented relationship, with unknown aetiology, between aortic valve stenosis and occult gastrointestinal bleeding in elderly patients. Despite several studies attempting to determine the prevalence and to discuss the aetiology, there are still many unanswered questions.

Methods.  A total of 288 consecutive patients with valvular aortic stenosis – mean age 73 ± 9 years aortic stenosis group (ASG) – were compared with 129 pacemaker‐treated patients, mean age 73 ± 9 years control group (CG). Screening for occult blood in stools was performed in both groups. Those with a positive Hemocult® test or a history of gastrointestinal bleeding were scheduled for further examination including upper endoscopy and colonoscopy. Template bleeding time was performed on patients in both groups and in patients with a prolonged bleeding time with an extended coagulation evaluation was carried out. Patients referred to aortic valve replacement and with a preoperatively prolonged bleeding time were re‐examined after surgery.

Results.  There was a significant difference in the number of subjects with prolonged bleeding time between groups (ASG 19; CG 2; P = 0.028). Re‐examination of the bleeding time after aortic valve surgery revealed normalized values in nine of 12 (P = 0.0003). The number of patients with positive Hemocult® test did not differ between groups (ASG 29; CG 12; NS). Comparison of the pressure gradient over the aortic valve demonstrated a significantly higher maximal gradient amongst patients with a preoperatively prolonged bleeding time (113 mm HG vs. 90 mmHG; P = 0.005).

Conclusion.  Prolonged bleeding time is related to valvular aortic stenosis and seems to be caused by acquired platelet dysfunction. The normalization of the bleeding time after valve surgery supports the hypothesis that the calcified cusps may interact with the platelet function.
Birth weight – a risk factor for progression in diabetic nephropathy?
Authors: Jacobsen P. , Rossing P. , Tarnow L. , Hovind P. , Parving H‐H.
Published: March 2003

Abstract.  Jacobsen P, Rossing P, Tarnow L, Hovind P, Parving H‐H (Steno Diabetes Center, Gentofte, Denmark). Birth weight – a risk factor for progression in diabetic nephropathy? J Intern Med 2003; 253: 343–350.

Objectives.  Intrauterine growth retardation, as seen in individuals with low weight at birth, may give rise to a reduction in nephron number. Oligonephropathy has been linked to hypertension and renal disease in adult life. We tested the concept that low weight at birth acts as a risk factor for progression of diabetic nephropathy.

Design and subjects.  We performed an observational follow‐up study of 161 (97 men) type 1 diabetic patients with diabetic nephropathy [mean age (SD): 35 (11) years, mean duration of diabetes: 22 (8) years]. All patients had been followed for at least 3 years [median (range): 8 (3–20)] with at least three measurements [9 (3–31)] of glomerular filtration rate (GFR) (51Cr‐EDTA). Information about birth size was obtained from midwife registrations.

Settings.  Steno Diabetes Center, a tertiary referral centre.

Main outcome measures.  Loss of kidney function according to birth weight and weight/length ratio at birth.

Results.  There was no correlation in univariate analysis between birth weight or weight/length ratio and rate of decline in GFR, neither in men nor in women. Furthermore, the 27 patients with birth weights below the 20th centile had a rate of decline in GFR [median (range)] similar to the 134 patients above: 2.6 (−4.7; 9.6) vs. 3.4 (−2.3; 19.3) mL min−1 year−1, respectively (NS). A multiple regression analysis revealed that albuminuria, arterial blood pressure, and haemoglobin A1C during follow‐up showed a significant correlation with the decline in GFR [R2 (adjusted) = 0.34], whereas birth weight and birth weight/length ratio did not.

Conclusions.  Our study does not suggest that weight at birth is associated with progression of established diabetic nephropathy in type 1 diabetic patients, whilst several other potential modifiable risk factors were identified.
Characterization of nanophase Al‐oxide/Al powders by electron energy‐loss spectroscopy
Authors: Fernández  , Sánchez‐López  , Caballero  , Martin  , Vacher  , Ponsonnet
Published: March 2003

Al nanoparticles were prepared by the inert gas condensation method. After passivation with oxygen and air exposure we obtained a powdered sample of an Al‐oxide/Al nanocomposite material. In the present paper we describe the use of the electron energy‐loss spectroscopy (EELS) technique in a transmission electron microscope to characterize such nanostructured powders compared with a microcrystalline commercial aluminium foil. Energy‐filtered images showed the presence of an alumina overlayer of ≈ 4 nm covering the aluminium nanoparticles (23 nm in diameter). EELS analysis enabled us to determine the total amount of Al2O3 and metallic Al and the structure of the alumina passivation overlayer in the sample. In particular, the extended energy‐loss fine structure analysis of the data showed a major presence of Al tetrahedrally coordinated with oxygen in the alumina passivation layer of Al nanoparticles instead of the octahedral coordination found for a conventional Al foil. This surprising effect has been attributed to the nanoscopic character of the grains. The analysis of the electron‐loss near‐edge structure also determines the presence of a certain degree of aggregation in this kind of powdered sample as result of the coalescence of the nanocrystalline grains. The procedure presented here may have the potential to solve other problems during characterization of nanostructured materials.
Repetitive cell ‘jumps’ during hypotonic lysis of erythrocytes observed with a simple flow chamber
Authors: Zade‐Oppen A.M.M.
Published: March 2003

This is the first report describing cell movements of a repetitive character during hypotonic lysis of erythrocytes (haemolysis). A new, simply constructed chamber is described for microscopy of freely suspended cells, for example, blood cells, during the inflow of a new medium. Hypotonic haemolysis of individual red blood cells was studied. During the first phase of haemolysis discontinuities were found: the cells made between zero and seven sudden movements or ‘jumps’, interpreted as caused by an ejection of cytoplasm due to excess intracellular hydraulic pressure and the formation of a hole. After pressure equilibration the hole resealed spontaneously. When, after one or two jumps, the inflow of hypotonic medium was stopped, the haemolytic process was interrupted but continued after restarting the flow. Inhibition of haemoglobin (Hb) release by 80% by external Ficoll® did not affect the number of ‘jumps’. Since the optical contrast was reduced owing to Hb release after the last jump, less than 20% of the Hb loss can be associated with the jumps. Ejections of faint clouds of Hb were observed mainly in the presence of Ficoll®, but only after the last jump.
Fluorescence photobleaching‐based shading correction for fluorescence microscopy
Authors: Ghauharali  , Hofstraat  , Brakenhoff
Published: March 2003

A thin fluorescent test layer, which is used in a practically mono‐exponential bleaching regime, is employed to determine separately the excitation intensity and the fluorescence detection efficiency distributions in the field of view of a confocal fluorescence microscope. We demonstrate that once these distributions are known, it is possible to correct an image of a specimen for intensity variations which are caused by spatial nonuniformities of the illumination and the detection efficiency of the microscope. It is indicated that, provided a photophysically well‐characterized fluorescent test layer is available, the method is potentially capable of quantifying the fluorescence intensities in an image of a specimen in terms of the fluorescence quantum yield, the absorption cross‐section and the concentration of the fluorophore in the specimen.
Crystallographic image processing approach to crystal structure determination
Authors: Li F. H.
Published: March 2003

It is shown that the crystallographic image‐processing technique based on the weak‐phase object approximation and on the combination of high‐resolution electron microscopy and electron diffraction is applicable to crystal structure determination. The technique consists of two stages: image deconvolution and phase extension. In the first stage an image taken at an arbitrary defocus condition can be transformed into the structure image with the resolution limited by the resolution of the electron microscope. In the second stage the image resolution is enhanced to the diffraction resolution limit so that most unoverlapped atoms can be resolved individually in the final image. Although the experimental diffraction intensities are available for the image deconvolution, they must be corrected for the phase extension. The proposed empirical method of electron diffraction intensity correction seems effective for obtaining a set of corrected diffraction intensities which are approximately equal to square structure factors.

When the crystal structure under examination belongs to a known typical type, it is easy to propose the structure model by referring to the deconvoluted image which reveals the low‐resolution structure, and the high‐resolution structure can also be determined by image simulation.
The evolution of electron image processing and its potential debt to image algebra
Authors: Hawkes P. W.
Published: March 2003

The types of digital electron microscope image processing of greatest interest are not the same in the three major types of electron microscope. In the TEM, electron tomography and crystallography, particularly for 3‐D reconstruction of biological specimens, and procedures that enable the physicist to establish the atomic structure, and especially defects in crystalline material, from one or more of a host of different records — bright‐ and dark‐field images, traditional or convergent‐beam diffraction patterns, energy‐loss spectra, holograms — have attracted the greatest attention. In the SEM, image enhancement and image analysis (counting and measurement of geometrical or compositional features of the image) have always been important and the earliest attempts to process SEM images were in these fields. In the STEM, it is the possibility of using all the information in the far‐field diffraction pattern from every element of the object that has provoked the most exciting and original ideas.

Electron images began to be processed by computer or by analog means just 30 years ago and during those years, images of every kind have likewise been enhanced or restored or analysed: in astronomy and medicine, in forensic science and in agriculture, in textile studies and the geosciences, similar algorithms have been developed, often with little awareness of related work. In order to harmonize all this material, an attempt to find a common language for representing it has been sought and the result is ‘image algebra’. This is a simple mathematical structure in which the basic element is not the pixel value but the image, which is a general notion: an array, the elements of which may be real or complex numbers or one‐ or two‐dimensional arrays of such numbers. An image whose pixel values are themselves images plays a very important part and is referred to as a ‘template’.

We show how the various image processing algorithms that have been found useful in electron microscopy can be expressed in terms of this algebra. Moreover, image algebra is not merely a convenient way of representing these algorithms; its simplicity and conciseness make it easy to recognize generalizations and variants of the original procedures. We draw attention to some of these and point out promising directions for future work, including the use of a new transform, the ‘slope transform’, for interpreting scanning tunnelling microscope images.
Probability estimations for fitted parameters — the EXPHER package
Authors: Taupin D
Published: March 2003

The general problem of fitting unknown parameters to experimental data is addressed in terms of probability laws, that is, answering the fundamental question: ‘what is the probability law of the various unknowns, knowing the data yielded by the experiments?’ The question appears to be an inverse problem whose solution is simple in theory, but whose practical implementation is so difficult that many an experimentalist reverts to heuristic methods of questionable reliability.

As an alternative solution, a freeware computer package — EXPHER — is presented which performs most of the tedious work involved in rigorous treatments, including related algebraic calculus.
Confocal microscopy and spectroscopy of InGaN epilayers on sapphire
Authors: O'DONNELL  , TOBIN  , BAYLISS  , VAN DER STRICHT
Published: March 2003

We report a preliminary investigation of spatial inhomogeneities in an InGaN epilayer using scanning confocal microscopy as the investigative tool. The Daresbury confocal microscope SYCLOPS provides simultaneous high quality reflection and fluorescence images of InGaN sample areas up to 500 μm square, even at room temperature. Sample cooling increases the brightness and quality of the fluorescence image, as expected. Spectral selection using interference filters permits identification of features close to sample edges resulting from the nitridation of indium droplets. The unexpected non‐coincidence of fluorescence and reflection features below 10 μm in size is tentatively attributed to the differing absorption strengths of different crystallites.
Surface‐polariton propagation for scanning near‐field optical microscopy application
Authors: Keilmann F.
Published: March 2003

Surface plasmon‐, phonon‐ and exciton‐polaritons exist on specific materials in specific spectral regions. We assess the properties of such travelling surface‐bound electromagnetic waves relevant for scanning near‐field optical microscopy applications, i.e. the tightness of surface binding, the attenuation, the phase velocity and the coupling with free‐space electromagnetic waves. These quantities can be directly determined by photographic imaging of surface plasmon‐ and surface phonon‐polaritons, in both the visible and mid‐infared regions. Focusing of mid‐infrared surface plasmons is demonstrated. Surface waveguides to transport and focus photons to the tip of a scanning near‐field probe are outlined.
Characterization of the fibre–matrix interfacial structure in carbon fibre‐reinforced polycarbosilane‐derived SiC matrix composites using STEM/EELS
Authors: Jiang  , Brydson  , Appleyard  , Rand
Published: March 2003

This paper presents a characterization study of the microstructural evolution of various carbon fibre‐reinforced polycarbosilane (PCS)‐derived SiC matrix composites during high temperature heat treatment. Both surface‐treated and untreated carbon fibre reinforcements were investigated. The STEM/EELS technique was found to be a particularly useful characterization tool. The results of quantitative EELS linescans have been interpreted in terms of the migration of gaseous SiO and CO, produced by the reaction between the small amount of SiO2 and excess carbon within the PCS‐derived SiC matrix, from the central matrix region towards the fibre–matrix interfaces. Generally, the migration of gaseous SiO and CO results in an enrichment of SiO2 at the region adjacent to the fibre–matrix interface. However, differing final composite microstructures are formed depending on the strength of the fibre–matrix bonding. In the case of strong fibre‐matrix interfacial bonding where few escape channels are present, a distinct Si–C–O layer was identified within the matrix adjacent to the fibre–matrix interface; both crystalline β‐SiC and the segregated Si–O–C phase coexist in this microstructure up to at least 1450 °C. In the case of weak fibre–matrix bonding this oxygen segregated interfacial layer is eventually removed at high enough temperatures. The final interfacial microstructure has important consequences for the mechanical properties of the composite material.
Local variations of the chemistry in as‐cast γ‐TiAl (TiBx) alloys and its consequence for thermomechanical treatments
Authors: Sternitzke  , Appel  , Wagner
Published: March 2003

The first part of the paper presents an accompanying investigation to a thermomechanical processing route of γ‐TiAl turbine blades. By means of scanning electron microscopy and energy dispersive X‐ray (EDX) analysis, the chemical homogeneity and the microstructures of γ‐TiAl as‐cast ingots, work pieces and the final turbine blades are determined. We find that the local Al‐content in as‐cast ingots can vary by more than 1.5 at.%. Large chemical inhomogeneities present in as‐cast ingots can only be eliminated to a certain degree by subsequent thermomechanical processing. An additional aim of the study is to assess the influence of a thermomechanical processing on the morphology of titanium boride precipitates and the α2‐Ti3Al‐phase.

The second part of the paper contains a detailed analytical study devoted to homogenization of a range of γ‐TiAl cast alloys. Different microstructures are generated in a laboratory‐scale argon‐arc furnace by both rapid and slow solidification rates and an additional homogenization treatment, respectively. Quantitative EDX analysis shows that only rapid solidification of ingots with a subsequent homogenization treatment leads to a nearly chemically homogeneous microstructure.
Oxidative stabilization of C/C tow pregs studied by light microscopy
Authors: Casal  , Bermejo  , Prada  , Granda  , Menéndez
Published: March 2003

Tow pregs obtained from polyacrylonitrile‐based carbon fibres and a commercial binder coal‐tar pitch were stabilized by oxidation at 548, 588 and 623 K for periods ranging between 1 and 15 h. The microstructural changes involved in the stabilization of tow pregs on the carbonized laminates were studied by light microscopy. Under the conditions studied, the oxidative stabilization of tow pregs produced a significant increase in carbon yield. At the same time, the development of porosity on carbonization was avoided and the size of the optical texture was reduced. However, the extreme oxidation of pitch components at the edges of the carbonized laminate adversely affected pitch binding capability and the sinterizability of the laminates.
ER‐Tracker dye and BODIPY‐brefeldin A differentiate the endoplasmic reticulum and Golgi bodies from the tubular‐vacuole system in living hyphae of Pisolithus tinctorius
Authors: Cole  , Davies  , Hyde  , Ashford
Published: March 2003

Two fluorochromes, ER‐TrackerTM Blue‐White DPX dye and the fluorescent brefeldin A (BFA) derivative, BODIPY‐BFA, label the endoplasmic reticulum (ER) in hyphal tips of Pisolithus tinctorius and allow its differentiation from the tubular‐vacuole system at the light microscope level in living cells. The ER‐Tracker dye labels a reticulate network similar in distribution to ER as seen in electron micrographs of freeze‐substituted hyphae. BODIPY‐BFA stains a thicker axially aligned structure with an expanded region at the apex, which is similar to that seen when hyphae are stained with ER‐Tracker dye in the presence of unconjugated BFA. This structure is considered to be ER modified by BFA, a view supported by ultrastructural observations of the effect of BFA on the fungal ER. Both fluorescent probes also stain punctate structures, which are most likely to be Golgi bodies. Neither probe labels the tubular‐vacuole system.
Cell wall secretion in the green alga Micrasterias
Authors: Lütz‐Meindl U. , Brosch‐Salomon S.
Published: March 2003

The monoclonal antibodies JIM 1 against non‐arabinogalactan epitopes, JIM 5 and JIM 7 recognizing unesterified and methyl‐esterified pectins, and JIM 8 specific for arabinogalactan proteins (AGPs) are used for investigating different stages of cell wall formation in high pressure frozen and freeze substituted Micrasterias cells by means of immunoelectron microscopy. The results show that the septum‐forming vesicles and the septum wall consist mainly of methyl‐esterified pectins which become only partly de‐esterified in the septum wall. Arabinogalactan proteins appear at the septum rim at the end of septum growth and are main constituents of the primary cell wall, together with esterified pectins. Only the outermost layer of the primary cell wall is labelled by JIM 5, indicating the presence of unesterified pectins. AGPs, non‐AGP epitopes indicated by JIM 1, and pectins are transported together in the contents of the primary wall, forming ‘dark vesicles’ from the site of their production at the dictyosomes to the plasma membrane. Labelling of exclusively the plasma membrane of the non‐growing semicell by JIM 1 and JIM 8 points towards a regulatory mechanism of membrane glycoproteins for vesicle fusion. The secondary cell wall of Micrasterias is not labelled by any of the antibodies used. JIM 4, JIM 15, JIM 84 and MAC 207 do not produce any specific staining in Micrasterias.