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Biomedical subjects

B Kristensen

Publications and source records attributed to B Kristensen.

At least 55 records · Page 3Linked to original sources
PubMed1997

Epidemiology and etiology of ischemic stroke in young adults aged 18 to 44 years in northern Sweden.

BACKGROUND AND PURPOSE: The aim of this study was to conduct a population-based epidemiological survey among young adults aged 18 to 44 years in Northern Sweden and furthermore to gain further insight into the etiology of ischemic stroke in this age group. METHODS: Two studies were done. In the first part, epidemiological data were collected to calculate incidence and mortality from 1991 through 1994. This was based on the World Health Organization Northern Sweden MONICA register of acute stroke events. Eighty-eight first-ever ischemic stroke patients were identified during that period. In the second part, 107 consecutive patients aged 18 to 44 years with ischemic stroke referred to a university hospital were studied prospectively during a 5-year period and were extensively evaluated according to a standardized protocol. On the basis of modified Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria, the patients were classified into eight subtypes of ischemic stroke. RESULTS: The average population-based annual incidence rate for ischemic stroke (cases per 100,000 per year) was 11.3 (95% confidence interval, 6.7 to 16.1). The case-fatality rate was 5.7%. According to the modified TOAST criteria, a probable cause of ischemic stroke was identified in 36% and remained unexplained in 21% of cases. Spontaneous cervical arterial dissection was the leading probable etiology (13%). Patent foramen ovale or atrial septal aneurysm was a possible cause of stroke in 28% of cases. The percentages of ischemic stroke attributed to IgG anticardiolipin antibodies (4.7%), atherothrombotic vasculopathy (3.7%), oral contraceptive use (7%), and migraine (1%) were lower than reported in recent clinical series. CONCLUSIONS: The incidence rate for ischemic stroke was higher than previously reported from most countries in Western Europe. The higher incidence was not explained by a higher prevalence of premature atherosclerotic vasculopathy. Without the additional diagnostic information derived from advanced cardiac imaging, the proportion of indeterminate cases would have constituted 37% of the patients.

Adolescent↗
PubMed1997

Double gloving as self protection in abdominal surgery.

OBJECTIVE: To investigate if double gloving can reduce the rate of perforation of glove barriers during abdominal surgery. DESIGN: Randomised controlled trial. SETTING: County hospital, Denmark. SUBJECTS: 400 glove barriers from principal surgeons and first assistants used at consecutive abdominal operations. INTERVENTION: Each participant was randomised to wear either a pair of single or double gloves. MAIN OUTCOME MEASURES: The number of perforated glove barriers in the two study groups. RESULTS: 40 single glove barriers perforated (20%) and in 8 of the double glove group both gloves perforated (4%) (p < 0.001). Glove barriers on non-dominant hands were more often perforated than those on dominant hands, and both the duration of the operation and the seniority of the doctor were associated with increased rates of perforation. CONCLUSION: Double gloving reduces the rate of perforation of glove barriers during abdominal surgery and thereby the number of episodes in which transmission of disease from patient to surgeon would be possible.

Abdomen↗
PubMed1996

[An outbreak of Streptococcus pyogenes infections in institutions for the mentally retarded in Greater Copenhagen 1995].

The largest reported outbreak of infections due to Streptococcus pyogenes, M-type 18, in recent years is described. Ninety persons at institutions for mentally retarded (73% residents) had infections due to the epidemic strain. Pharyngitis and scarlatina were the most common infections. Six patients died, five having a streptococcal toxic shock syndrome. During the outbreak an intensive surveillance was carried out together with improved infection control measures and prompt culturing of residents and employees before antimicrobial treatment. The primary outbreak was confined but a secondary outbreak could not be prevented. This was probably due to difficulties in implementing proper isolation precautions in this setting.

Adult↗
PubMed1996

Femoral fractures in postmenopausal breast cancer patients treated with adjuvant tamoxifen.

The anti-estrogen tamoxifen is the prevalent endocrine treatment in postmenopausal breast cancer patients. However, nothing is known about the long-term effects of the drug on the skeleton as assessed by the occurrence of fractures. We investigated the occurrence of fractures of the femur in patients from a Danish Breast Cancer Cooperative Group (DBCG) trial initiated in 1977 by a linkage of data from the Danish National Registry of Patients with data from the DBCG registry. 1716 postmenopausal women with high-risk breast cancer were randomized to local radiotherapy with or without tamoxifen, 30 mg daily for 1 year. Fifty-one patients in the control group had one femoral fracture and 64 tamoxifen treated patients had one femoral fracture. Eleven patients in the control group had one trochanteric fracture compared to 27 patients in the tamoxifen group (logrank = 5.28. P = 0.022; hazard ratio = 2.12, 95% CL 1.12, 4.01). The results could not be explained by a longer survival in the tamoxifen group nor by bone metastases with pathological fractures. In conclusion, our study suggests that tamoxifen does not seem to offer protection against fractures in old age and may even increase the risk of fractures at particular sites. This hypothesis needs to be disproved or confirmed in other trials.

Aged↗
PubMed1996

Regional cerebral blood flow, white matter abnormalities, and cerebrospinal fluid hydrodynamics in patients with idiopathic adult hydrocephalus syndrome.

OBJECTIVES--(1) to evaluate regional cerebral blood flow (rCBF) with single photon emission computed tomography and 99mTc-hexamethylpropyleneamine oxime in patients with the idiopathic adult hydrocephalus syndrome (IAHS); (2) to examine regional cerebral blood flow (rCBF), gait, and psychometric functions before and after CSF removal (CSF tap test); (3) to assess abnormalities in subcortical white matter by MRI. METHODS--Thirty one patients fulfilling the criteria for IAHS (according to history and clinical and neuroradiological examination) were studied. Quantified gait measurements, psychometric testing, and rCBF before and after removal of CSF were obtained. Pressure of CSF and CSF outflow conductance were investigated with a constant pressure infusion method. Brain MRI was used to quantify the severity of white matter lesions and periventricular hyperintensities. In IAHS a widespread rCBF hypoperfusion pattern was depicted, with a caudal frontal and temporal grey matter and subcortical white matter reduction of rCBF as the dominant feature. Removal of CSF was not accompanied by a concomitant increase in rCBF. Significant white matter lesions were detected only in a minority of patients by MRI. An altered CSF hydrodynamic state with a higher CSF pressure and lower conductance was confirmed. IAHS is characterised by an abnormal CSF hydrodynamic state, associated with a widespread rCBF reduction with preference for subcortical white matter and frontal-temporal cortical regions. Furthermore in most patients MRI did not show white matter changes suggestive of a coexistent subcortical arteriosclerotic encephalopathy. At least in the idiopathic group of patients with AHS, measurements of rCBF before and after temporary relief of the CSF hydrodynamic disturbance will not provide additional information that would be helpful in the preoperative evaluation but is suggestive of a preserved autoregulation of rCBF.

Aged↗
PubMed1995

The predictive value of cerebrospinal fluid dynamic tests in patients with th idiopathic adult hydrocephalus syndrome.

OBJECTIVE: To evaluate the predictive value of the cerebrospinal fluid (CSF) tap test and CSF outflow conductance in the selection of patients with the idiopathic adult hydrocephalus syndrome, defined exclusively on a clinical basis, for shunt surgery. DESIGN: A prospective, consecutive case series. All patients were assessed before surgery and at 3 months after shunt placement. Preoperatively, CSF pressure, conductance, and CSF formation rate were assessed by a constant-pressure infusion method. Improvement in gait and cognitive functions after removal of CSF was noted (ie, with the CSF tap test). Postoperatively, the infusion method was used to evaluate shunt function. SETTING: Tertiary, academic referral center. PATIENTS: Thirty-five patients with idiopathic adult hydrocephalus (normal-pressure hydrocephalus) syndrome based on conservative clinical criteria. No predictive tests were used for inclusion. All patients had a typical gait disturbance and a communicating hydrocephalus. Twenty-eight patients also had dementia or incontinence, or both. INTERVENTION: The CSF diversion (Cordis, [Orbis-Sigma]) valve, six patients; Hakim's standard system (Cordis Hakim standard system), 29 patients. OUTCOMES OF SURGERY: Serial videotaping of gait, a comprehensive neuropsychologic battery, and the Bartel index of activities of daily life. RESULTS: Gait was improved in 25 (72%) of the 35 patients, whereas the Bartel index remained unchanged. The conditions of five of seven patients with gait disturbance as the sole symptom improved. The spatial function (37% improved) and the findings from the Fuld object memory tests (29% improved) were significantly improved. Shunt dysfunction could not explain the lack of effect of an operation in the remaining patients. It should be noted that these results obtained at 3 months postoperatively may not be applicable in a long-term perspective. The CSF outflow conductance or CSF tap test were not able to identify those patients who would or would not benefit from a CSF diversion procedure. However patients had a lower conductance and a higher CSF pressure than did control subjects. CONCLUSIONS: Considerable improvement in gait was seen, but cognitive function was little affected. The CSF tap test or conductance does not provide additional information that is necessary to distinguish between patients whose conditions will or will not respond to shunting, when selection for surgery is based on conservative clinical criteria.

Activities of Daily Living↗
PubMed1995

Endocarditis caused by Aerococcus urinae, a newly recognized pathogen.

Aerococcus urinae is a newly described pathogen. A case of Aerococcus urinae endocarditis is presented, the primary focus being a urinary tract infection. The diagnosis of endocarditis was supported by isolation of Aerococcus urinae from blood as well as from heart vegetations.

Aged↗
PubMed1995

Bacteremia/septicemia due to Aerococcus-like organisms: report of seventeen cases. Danish ALO Study Group.

Some Aerococcus-like organisms (ALOs) have recently been described in Denmark. The bacteria were originally isolated from the urine of elderly patients with urinary tract infections. Since 1987, we have identified 17 cases of bacteremia/septicemia in which ALOs have been isolated in pure culture of blood; we report the data from these cases. Six of the patients presented with endocarditis, eight presented with urosepticemia, and three presented with septicemia. In all but one of the reports, the urinary tract was suspected as the focus of infection, and ALOs were isolated from the urine of nine patients. All but one patient had predisposing illnesses; these were predominantly of urinary or cardiac origin. Five patients died of their infection, two survived the infection but eventually died during hospitalization, and 10 recovered. All of the patients received adequate antimicrobial therapy.

Aged↗
PubMed1995

A 13-year survey of bacteraemia due to beta-haemolytic streptococci in a Danish county.

During 1981-1993, 229 episodes of bacteraemia due to beta-haemolytic streptococci of groups A, B, C and G were diagnosed in the County of Northern Jutland, Denmark. The annual rates for bacteraemia were quite constant during the 13-year period for each streptococcal group. Group A streptococcal (GAS) bacteraemia was the most frequent, comprising 1.4% of all bacteraemias. The incidence of GAS bacteraemia was 1.8/100,000/year in children < 5 years of age and 4.7/100,000/year in patients > 60 years old. With the notable exception of group B streptococcal (GBS) bacteraemia in neonates, beta-haemolytic streptococci of groups B, C (GCS) and G (GGS) were isolated mostly from elderly patients. Except for GBS bacteraemia in neonates, approximately one-third of the bacteraemias in each group was nosocomially acquired. Predisposing factors included operative procedures in GAS and GCS bacteraemia, and diabetes mellitus in GBS bacteraemia. The skin was the most common primary focus in GAC, GCC and GGS bacteraemias, whereas the urinary tract was the commonest focus in GBS bacteraemia in adults. The mortality rates in GAS, GCS, GGS, and adult GBS bacteraemia were 23%, 16%, 17% and 19%, respectively. Of the 23 fatal cases of GAS bacteraemia, 57% died within 24 h after blood cultures had been obtained.

Adolescent↗
PubMed1995

Cerebrospinal fluid shunt dynamics in patients with idiopathic adult hydrocephalus syndrome.

The objective was to assess CSF dynamics of different shunt constructions in patients with adult hydrocephalus syndrome and correlate these findings to clinical outcome, neuroradiology, and the specifications of the shunts provided by the manufacturer. Thirty four patients with idiopathic adult hydrocephalus (normal pressure hydrocephalus) syndrome were included in a prospective, consecutive case series. A differential pressure valve (Cordis Hakim standard system) was used in 28 patients and a variable resistance valve (Cordis Orbis-Sigma) in six. A constant pressure infusion method was used; CSF pressure and conductance were determined before surgery. Three months after shunt placement CSF pressure, the "pressure v flow" curve, and gravity induced flow were measured. There was no difference between mean preoperative and postoperative resting CSF pressures in patients with Hakim shunts. The opening pressures of the Hakim shunts were higher than the value proposed by the manufacturer. A pronounced gravity effect induced CSF flow and decrease of the CSF pressure. In functioning variable resistance valves, CSF dynamics normalised postoperatively. There was no gravity effect and the characteristics shaped "pressure v flow" curve was sometimes seen. Six patients (three differential pressure valves, three variable resistance valves) had non-functioning shunts. Four of these patients were improved after the operation but improvement was transient in three. In all patients, there was no relation between the width of the ventricles and clinical improvement or CSF pressure. In conclusion, the differential pressure valve system does not behave according to the specifications provided by the manufacturer. A decrease in CSF pressure in patients with this shunt was solely due to the effect of gravity. Eleven percent of the differential pressure valves and 50% of the variable resistance valves were non-functioning. In the functioning variable resistance valves, the antisiphon system seems to be effective.

Aged↗
PubMed1995

Capnocytophaga (Capnocytophaga ochracea group) bacteremia in hematological patients with profound granulocytopenia.

The clinical and microbiological features of 7 cases of bacteremia due to Capnocytophaga (Capnocytophaga ochracea group) are reported. They were diagnosed during 1991-93 at three hospital clinics. Five patients were < 10 years old and all had hematological disorders, 4 acute lymphoblastic leukemia and 1 each had aplastic anemia, non-Hodgkin lymphoma, and myelodysplastic syndrome. All were profoundly granulocytopenic with an absolute granulocyte count < 0.13 x 10(9)/l, and all but 1 had oral lesions as a possible portal of entry. A favourable response to antibiotic therapy was recorded in all patients but one who, being profoundly granulocytopenic, rapidly succumbed to Pseudomonas aeruginosa septicemia. None of the isolates were beta-lactamase producers. In addition to penicillin the isolates were susceptible to broad-spectrum cephalosporins and ciprofloxacin, but resistant to aminoglycosides.

Adolescent↗
PubMed1995

Self-induced bacteremia. Case report.

We describe a patient with perforated appendicitis who postoperatively suffered repeated episodes of shaking chills and temperature spikes. Initial blood cultures yielded growth of Flavobacterium meningosepticum, Pseudomonas putida and Pseudomonas paucimobilis, and succeeding blood cultures growth of Pseudomonas acidoverans. These bacteria in combination led to a suspicion of self-inoculation of contaminated water through an intravenous catheter. Antibiotic treatment had no effect on the symptoms, which only ceased when the intravenous catheter was removed.

Adult↗
PubMed1994

[Gentamycin resistant Enterobacteriaceae at a neonatal care unit].

A case of septicaemia in a seven-day-old infant with a gentamicin-resistant strain of Enterobacter cloacae prompted an epidemiological survey in a neonatal unit. Another 18 patients harboured gentamicin-resistant Enterobacteriaceae without symptoms. Control of the outbreak was achieved by cohort nursing, strict hygiene and reduction of aminoglycoside consumption by 50%. Efficiency of the measures was monitored by weekly faecal samples from all patients. All strains produced the aminoglycoside modifying enzyme AAC(3)II. The resistance was plasmid-mediated.

Cohort Studies↗
PubMed1994

Polymorphism of bovine MHC class II genes. Joint report of the Fifth International Bovine Lymphocyte Antigen (BoLA) Workshop, Interlaken, Switzerland, 1 August 1992.

Polymorphism of the bovine DRB, DQA, DQB, DYA, DOB and DIB genes was investigated using restriction fragment length polymorphism (RFLP) analysis, isoelectric focusing (IEF), class II serology and polymerase chain reaction (PCR) based typing techniques. The simultaneous application of multiple typing techniques and the characterization of multiple genes resulted in a greatly enhanced picture of the bovine class II regions. Thirty-eight class IIa (DR-DQ) and 5 class IIb (DYA-DOB-DIB) haplotypes were defined. It was found that IEF types were associated with DRB3 polymorphism defined by DRB3 PCR-RFLP and DRB3 microsatellite PCR. Serologically defined polymorphism was associated with distinct molecular/IEF motifs and, therefore, DR and DQ specificities could be tentatively distinguished. Although the DR and DQ genes are tightly linked, neither DR nor DQ typing defined all of the class IIa region polymorphism. Furthermore, even the most powerful DRB3 typing technique, DRB3 PCR-RFLP, failed to detect all expressed DRB3 polymorphism. All detected DRB3 polymorphism could, however, be distinguished with a combination of two molecular techniques: DRB3 PCR-RFLP and DRB3 microsatellite PCR. RFLP typing with transmembrane probes detected significantly less polymorphism than typing with cDNA or exon probes. However, the transmembrane probes were useful because they were locus specific. The presence of only 5 of 12 possible class IIb haplotypes was unexpected and indicates that the DYA, DOB and DIB genes are tightly linked.

Animals↗
PubMed1994

CSF concentration gradients of monoamine metabolites in patients with hydrocephalus.

Concentration gradients of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MHPG), were assessed in 762 successive CSF fractions (2 ml lumbar CSF) from 15 patients with the adult hydrocephalus syndrome (AHS) and 11 patients with hydrocephalus of other causes (mixed group). A mean volume of 49.6 (SD 11.8) ml CSF was removed in the AHS group and 56.4 (10.2) ml in the mixed group. The CSF was collected with a specially designed carousel fraction collector and the corresponding CSF dynamics were continuously registered by a constant pressure CSF infusion method. Pronounced gradients in CSF HVA and CSF 5-HIAA were seen in both patient groups in the first 25 ml of CSF removed. The concentration curves levelled off, despite the removal of larger amounts of CSF and stabilised at about twice the initial concentrations. This phenomenon has not been described before. Concentrations of HVA and 5-HIAA in the first CSF fraction correlated strongly with concentrations in fractions up to about 40 ml. A positive correlation between the first fraction of CSF HVA and CSF 5-HIAA concentrations and CSF outflow conductance was found in the AHS group. There was no gradient in MHPG. It is suggested that the rostrocaudal gradients in CSF HVA and 5-HIAA may be explained by a downward flow of CSF along the spinal cord with absorption of metabolites occurring during passage. Mixing of CSF from different CSF compartments, extraventricular production sites of CSF, clearance of metabolites to venous blood or extracellular fluid, and CSF outflow conductance are probably important determinants of the plateau phase in patients with hydrocephalus. It is concluded that lumbar CSF does not exclusively reflect the concentrations of HVA, 5-HIAA, or MHPG in the ventricles. It should be noted that these results obtained in patients with hydrocephalus may not be applicable to other groups of patients or normal subjects.

Aged↗
PubMed1994

Tamoxifen and bone metabolism in postmenopausal low-risk breast cancer patients: a randomized study.

PURPOSE: This trial was undertaken to evaluate the effect of adjuvant tamoxifen on bone metabolism in postmenopausal women undergoing surgery for low-risk breast cancer. PATIENTS AND METHODS: In an open trial, 25 women were randomized to receive tamoxifen 30 mg/d for 2 years, and 25 women constituted the control group. Twenty women treated with tamoxifen and 23 women in the control group provided data for the analysis. Inclusion criteria were operation for low-risk breast cancer and cessation of menstruations for more than 1 year. Exclusion criteria were presence of metastases, disorders of bone metabolism, contraindications against tamoxifen, use of drugs with influence on bone metabolism, ailments that made bone mineral measurements impossible, and age greater than 65 years. Repeated measurements of bone mineral density and content at the lumbar spine and forearms, serum alkaline phosphatase, phosphate, and ionized calcium were performed in all patients. RESULTS: Lumbar spine bone mineral density increased during the first year in women treated with tamoxifen and then stabilized, compared with decreased bone mineral density in the control group (P = .00074). Bone mineral content at the forearms remained almost stable in tamoxifen-treated women compared with a decrease in the control group (P = .024). Serum alkaline phosphatase, phosphate, and ionized calcium decreased in the tamoxifen group (P < .00001, P = .002, and P = .002, respectively). CONCLUSION: Tamoxifen has estrogen-like effects on bone metabolism that result in an increase and stabilization of bone mineral density in the axial skeleton and a stabilization of bone mineral content in the appendicular skeleton.

Absorptiometry, Photon↗
PubMed1993

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies.

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P < 0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.

Alleles↗