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Biomedical subjects

M Christensen

Publications and source records attributed to M Christensen.

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

[Transnasal gastroscopy].

The use of transnasal endoscopy has not been reported earlier in Denmark. This study describes the preliminary experiences with transnasal gastroscopy using the Olympus XGIF-N200 prototype. Patients scheduled for diagnostic gastroscopy were examined transnasally. The patients answered questions regarding anxiety and discomfort, and the endoscopist commented on the quality of the procedure. Of sixty patients included, 56 (93%) were examined transnasally. Two patients did not have nasal passage and were examined orally, and two patients were examined with standard gastroscope because of technical difficulties. Sixty-eight percent of the procedures were unsedated, 55% of the patients did not experience gag-reflexes. The procedure was described by most patients as "slightly uncomfortable". Twenty-five percent had uncomplicated epistaxis. Pulse rate and saturation levels were stable. Transnasal gastroscopy seems to be well tolerated by the patients, as both subjective and objective criteria were better than those for conventional gastroscopy.

Gastroscopes↗
PubMed2000

Microsatellite alterations in urinary sediments from patients with cystitis and bladder cancer.

Microsatellite instability (MIN) and loss of heterozygosity (LOH) in bladder cancer have been suggested for diagnosis and follow-up of bladder cancer based on urinary sediments, reflecting tumor alterations. We have examined 6 microsatellites in urine sediments from 11 patients with transitional-cell carcinomas (TCC) and in 31 patients with benign prostatic hyperplasia (BPH), 22 of whom had cystitis. In the TCC patients, tumor tissue was available for comparison with urine. Microsatellites were amplified by PCR and compared with leukocyte DNA from the same individual in silver-stained gels. Altered mobility of bands, new bands and loss of bands were scored. We found MIN and LOH at relatively high frequency in markers from chromosomes 8 and 14 in urine from patients with TCC, but also in BPH patients who had cystitis. Even control patients with BPH without cystitis showed some instability and some losses. Novel bands in urine occurred significantly more often among TCC patients than among BPH patients with or without cystitis (p < 0.001). Band shifts in urine appeared to be more associated with BPH plus cystitis than with TCC. The alterations we found in urine from patients with bladder cancer did not always reflect those found in their tumors, the occurrence of novel bands being significantly higher (p < 0.008) in tumor tissue than in corresponding urine. In conclusion, microsatellite alterations in urine are indicators not only of malignancy but also of inflammatory conditions.

Adult↗
PubMed2000

Use of cloprostenol as an abortifacient in the llama (Lama glama).

As part of a larger project investigating the development and heritability of choanal atresia glama), it was necessary to develop a protocol for aborting llamas at various stages of gestation. Twenty-seven animals between 4 and 7 mo of gestation were successfully aborted a total of 53 times following two 250 microg intramuscular injections of cloprostenol at 24 h intervals. Abortion was induced once in 10 animals and multiple times (range 2 to 5) in 17 animals. Twenty-four animals (45.2%) aborted 3 d following the first injection, with 20 animals (37.7%) aborting 4 d post prostaglandin administration. Other animals aborted at 2 d (n=6, 11.3%), 5 d (n=2, 3.8%), and 7 d (n=1, 1.9%) following drug administration. Forty-nine (92.5%) of the abortions occurred following a single series of injections, while 4 animals (7.5%) aborted following a second series of injections. No confirmed pregnant animals failed to abort following the second series of cloprostenol injections. Conception rates in animals rebred 2 to 4 wk following an abortion were comparable to those of untreated animals in the research herd. Unlike the severe hypertension and death that has been reported following dinoprost tromethamine administration in the llama, no adverse reactions were observed in this study following cloprostenol administration. The results demonstrate that llamas can be safely and effectively aborted up to 7 mo of gestation (normal full term gestation = 342 +/- 10 days) without adverse effects on subsequent fertility.

Abortifacient Agents↗
PubMed2000

Loss of heterozygosity at 1p, 8p, 10p, 13q, and 17p in advanced urothelial cancer and lack of relation to chemotherapy response and outcome.

Studies of urothelial tumors have identified structural abnormalities in a number of chromosomes. This study aimed to identify specific genetic changes of patients with advanced urothelial cancers, and relate these changes to increased chemotherapy sensitivity or good prognosis. We screened 56 muscle-invasive bladder cancer tumors for loss of heterozygosity (LOH) at chromosome 1p, 8p, 10p, 13q, and 17p with PCR using 6 microsatellite markers. All patients had recurrent locally advanced or metastatic disease. DNA was extracted after microdissection of the primary tumor and normal tissue from paraffin-embedded specimens. The PCR products were electrophoresed in an ABI Prism 377 DNA sequencer and the alleles from tumor DNA and normal tissue DNA were analyzed using the GeneScan program. The LOH findings were correlated with response to chemotherapy and survival. Allelic loss of specific markers was present in 26-50% of the informative tumors. The most frequent LOH was observed at 17p, supporting the notion that this region may contain genes of importance to urothelial cancer progression. The overall rate of response to chemotherapy was 48%, and ranged from 40% to 56% according to specific LOH changes. The median survival of all patients from start of chemotherapy was 5.8 months and ranged from 5.3 to 7.9 months for patients with specific LOH changes. Response and survival of patients with no lost markers was the same size, compared to patients with one, two, or more lost markers. Specific genetic changes were detected in a significant number of tumors from patients with advanced urothelial cancer. These changes were not predictive of response to chemotherapy or of the duration of survival.

Adult↗
PubMed2000

Postoperative pain control by epidural analgesia after transabdominal surgery. Efficacy and problems encountered in daily routine.

BACKGROUND: The efficacy of postoperative epidural pain treatment has been well documented in controlled studies. However, the literature concerning results of daily routine use of this method often only emphasises certain aspects of it. METHODS: A prospective study of 168 patients scheduled for major surgery with transabdominal access was performed in order to evaluate efficacy, side effects, complications and rate of acceptance of postoperative epidural pain treatment. The epidural catheter was placed before surgery and the patients received epidural analgesia by a bupivacaine/morphine mixture for 3 days postoperatively, continued by another 3 days with bolus injections of morphine only. RESULTS: Only few complications followed the insertion of the epidural catheter, but in about 16% of the patients the epidural catheter or the drugs administered by it made reinsertion or change in the type of analgesia necessary during the first 3 post-operative days. Despite the possibility for individualising the treatment and p.r.n. analgesics, pain relief when coughing and moving during day 1-3 was insufficient in 30-50% of the patients. Serious side effects were rare, but pruritus was frequent, as were the symptoms of nausea and vomiting. The patients were generally satisfied with the treatment; however, a small group had unacceptable pain when the epidural catheter was inserted. CONCLUSION: Analgesia was insufficient when coughing and moving in an unacceptably large number of the patients. Also the number of epidural catheter related problems was high. In order to make early intervention possible, the patients and epidural catheters should be observed daily and systematically by members of the staff competent to detect possible problems.

Abdomen↗
PubMed2000

Effects of advanced glycation end-product inhibition and cross-link breakage in diabetic rats.

The accelerated formation of advanced glycation end-products (AGEs) due to elevated glycemia has repeatedly been reported as a central pathogenic factor in the development of diabetic microvascular complications. The effects of a novel inhibitor of AGE formation, NNC39-0028 (2,3-diaminophenazine), and a breaker of already formed AGE cross-links, N-phenacylthiazolium bromide (PTB), were investigated in streptozotocin-diabetic female Wistar rats. Diabetes for 24 weeks resulted in decreased tail collagen pepsin solubility, reflecting the formation of AGE cross-linking. Collagen solubility was significantly ameliorated by treatment with NNC39-0028, whereas PTB had no effect. Increased urinary albumin excretion (UAE) in diabetic rats was observed in serial measurements throughout the study period, and was not reduced by any treatment. Vascular dysfunction in the eye, measured as increased clearance of 125I-albumin, was induced by diabetes. NNC39-0028 did not affect this abnormality. This study demonstrated a pharmacological inhibition of collagen solubility alterations in diabetic rats without affecting diabetes-induced pathophysiology such as the increase in UAE or albumin clearance. Treatment with PTB, a specific breaker of AGE cross-links, had no effects in this study.

Albuminuria↗
PubMed2000

Vagal withdrawal during endoscopic retrograde cholangiopancreatography.

BACKGROUND: Patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) are at risk of developing cardiorespiratory complications, but the mechanism is still unknown. Treatment with metoprolol 2 h before the endoscopy has been shown to decrease the incidence of myocardial ischaemia during ERCP. The present study evaluated whether the endoscopic stress would decrease vagal tone and whether metoprolol given before the procedure could prevent this defence-like reaction. METHODS: Thirty-eight patients were randomized to receive either placebo or 100 mg metoprolol 2 h before ERCP. During ERCP the patients were monitored with a Holter tape recorder. Holter tapes from 31 patients (16 receiving metoprolol) were available to analyse the ratio of the standard deviations of the RR intervals (SDRR) to the mean RR intervals (measure of vagal tone) during ERCP. RESULTS: A decreased vagal tone during the ERCP was found, but we observed no difference between the metoprolol and the placebo group. For both groups the lowest vagal tone occurred at maximum heart rate during endoscopy. The SDRR/meanRR ratio returned towards base line for the subsequent 60 min after endoscopy. CONCLUSIONS: The existence of a defence-like reaction ('vagal withdrawal') during ERCP has been shown. Metoprolol given 2 h before the procedure did not affect the occurrence of this phenomenon. The interaction of other periendoscopic factors is still unclear and should be studied further.

Adrenergic beta-Antagonists↗
PubMed2000

Efficient mutation detection in mismatch repair genes using a combination of single-strand conformational polymorphism and heteroduplex analysis at a controlled temperature.

Single-strand conformational polymorphism analysis (SSCP) and heteroduplex analysis (HD) were tested as methods for mutation screening with respect to experimental variation, sensitivity, and specificity. Thirty-nine fluorescently labeled PCR products covering the two mismatch repair genes, hMLH1 and hMSH2, were tested in 15 patients for pattern changes, using SSCP and HD at two temperatures, in a total of 2340 runs. SSCP was most efficient in detecting base changes, whereas HD was the method of choice when detecting deletions. SSCP and HD at 20 degrees C were most effective (sensitivity 97%, specificity 49%), and SSCP and HD at 10 degrees C gave no additional information, except in one case where an exon had two base changes. Several mutations only showed a small pattern change in one of the two strands, most explicit at 20 degrees C. No correlation between the type of base change and the size or direction of the pattern changes could be found.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Adopted adolescents' overrepresentation in mental health counseling: adoptees' problems or parents' lower threshold for referral?

UNLABELLED: A larger proportion of adopted adolescents receive mental health counseling than do their nonadopted peers. Adoptees might have more problems that require counseling, or their adoptive parents might have a lower threshold for referral (or both). OBJECTIVE: To test the hypothesis that both the extent of adolescents' problems and their adoption status would predict whether adolescents received psychological counseling, after controlling for family demographic characteristics. METHOD: Two large data sets collected from 1994 through 1996 by the National Longitudinal Study of Adolescent Health (Add Health) were used. In parallel analyses of the 2 data sets, hierarchical logistic regression models were implemented to assess the incremental effects of problem behaviors, family characteristics, and adoption status on adolescents receiving counseling. RESULTS: Selected adolescents' problems and family demographic characteristics were significant predictors for having received counseling, but, after controlling for these variables, adoptees were still about twice as likely as nonadoptees to have received counseling. CONCLUSIONS: Prevalence of problems, adoptive family characteristics, and adoption status must all be taken into account to understand why adoptees are more likely to receive counseling. Clinicians should be sensitive to issues that are especially salient in adoptive families.

Adolescent↗
PubMed2000

Evaluation of caffeine as an in vivo probe for CYP1A2 using measurements in plasma, saliva, and urine.

Twenty-five healthy volunteers were given 100 mg caffeine orally and several estimates of cytochrome P450 1A2 (CYP1A2) activity were evaluated. The validation was performed by correlation of different parameters in plasma, saliva, and urine to two measures of caffeine clearance, CL(oral) and CL(137X-->17X) that served as standards of reference. Two subjects were excluded because of noncompliance with a caffeine-free diet. In the remaining 23 subjects, both plasma and saliva total clearances of caffeine were highly correlated with each other (r(s) = 0.97, p < 0.0001). The ratio 17X/137X restricted to one sampling point taken 4 hours after dose, showed a high correlation (r(s)) with CL(oral) and CL(137X-->17X) in plasma (0.84/0.83) and saliva (0.82/0.77) (p < 0.0001 for all the correlation values) where 17X is 1,7-dimethylxanthine (paraxanthine) and 137X is 1,3,7-trimethylxanthine (caffeine). Additionally, the ratio (AFMU + 1U + 1X + 17U + 17X)/137X in a 0-24 hours urine sampling showed the highest correlation with CL(137X-->17X) (r(s) = 0.85, p < 0.001) where AFMU is 5-acetylamino-6-formylamino-3-methyluracil, 1U is 1-methyluracil, 1X is 1-methylxanthine, and 17U is 1,7-dimethyluric acid. The major estimates of CYP1A2 activity were significantly less in nonsmoking females, and this probably was related to the use of oral contraceptives in this subpopulation. In summary, among caffeine-based approaches for CYP1A2, the authors recommend either plasma or saliva 17X/137X ratio and the urinary (AFMU + 1U + 1X + 17U + 17X)/137X ratio during a sampling interval of at least 8 hours, starting at time zero since caffeine intake. These indices are simple, reliable, and relatively inexpensive estimates of CYP1A2 activity to be used in the study of human populations.

Adult↗
PubMed2000

Please pass the cauliflower: a recipe for introducing undergraduate students to brain structure and function.

Neurophysiology/pathophysiology content is a frequent source of anxiety for undergraduate students and their instructors. This learning module supplements traditional lecture and overhead presentations to offer a novel, nonthreatening, and entertaining introduction to neuropathology. The module is based on a ridiculous analogy between the human brain and the cauliflower. This module has been used with both underclassmen and more advanced health science undergraduate students and has produced enthusiastic student responses while deescalating both student and instructor anxiety.

Aphasia↗
PubMed2000

Transnasal gastroscopy.

INTRODUCTION: The use of transnasal gastroscopy (TNG) has not previously been described in a Danish hospital. The method seems to be better tolerated compared with conventional oral gastroscopy. METHODOLOGY: Patients scheduled for diagnostic gastroscopy were included, and examined with a thin endoscope transnasally (Olympus XGIF-N200 prototype, diameter 6 mm). RESULTS: Sixty patients were included, and transnasal gastroscopy was possible in 56 patients (93%). Two patients were examined transorally, as there were no passage through the nose. One patient had fluid retention in the stomach, and in another patient the endoscope looped continuously in the esophagus, preventing introduction into the stomach. The quality in 48 examinations (80%) was satisfactory. Unsedated examination was possible with 38 patients (68%), and 55% of patients did not have gag-reflexes or nausea. The unpleasantness of TNG was rated on a scale from 1 to 4, and the median score was 2 (slightly unpleasant). TNG would be the method of choice in 88% of patients, if they should undergo another gastroscopy in the future. Fifteen patients had uncomplicated epistaxis as the only complication. Pulse rate and oxygen saturation values were stable during the TNG examinations. CONCLUSION: TNG with a thin endoscope seems to be well tolerated by the patients, this is supported by the subjective experience of the patients, and also by the stable values of oxygen saturation and heart rate during the examinations.

Adult↗
PubMed1999

[MMR-vaccination of children allergic to eggs].

To re-evaluate the recommendations for MMR-vaccination of children known to be allergic to eggs a descriptive study was carried out in which all reported allergic side effects for 1987-1996 were studied. During the 10 year period 1,200,000 MMR vaccinations were given. Eighteen were found with immediate type hypertensity, but only eight presented symptoms within 24 hours. One child with egg-allergy reacted within 15 min presenting rhinitis and respiratory difficulty. None had anaphylactic shock. It was concluded that MMR vaccine may be administered to children allergic to eggs when given in a paediatric ward where appropriate emergency treatment is available.

Child↗
PubMed1999

Continuous pulse oximetry in the general surgical ward: Nellcor N-200 versus Nellcor N-3000.

New measurement principles in pulse oximetry have been introduced to decrease the incidence of false movement alarms. Experimental studies have shown that the new Nellcor Symphony N-3000 may reduce the incidence of false alarms when monitoring during different activities. We compared the Nellcor Symphony N-3000 with the Nellcor N-200 pulse oximeter, when monitoring patients in the general surgical ward. Twenty-two patients were monitored during unrestricted ward activities for a total of 275 h with a N-3000 and a N-200 pulse oximeter simultaneously. Data were analysed for lack of concordance between the two pulse oximeters with respect to frequency of registered hypoxaemic episodes and thus the amount of time spent in the alarm state. The median number of desaturation episodes with the N-200 was 18 (range 0-511) compared with four (range 0-476) with the N-3000 (p < 0.0001). The median number of drop-outs (loss of signal) was 13 (range 1-46) with the N-200 compared with nine (2-41) with the N-3000 (p = 0.06). The N-200 registered saturation values of 85% or below for 23% of the observation time compared with 6% of the observation time with the N-3000 pulse oximeter (p < 0.0001). The different working principles of the two generations of oximeters were reflected in the present results derived from a clinical setting. The Nellcor Symphony N-3000 may offer an advantage compared with the Nellcor N-200, because of the reduced frequency of alarms and total time in alarm when monitoring patients in the general surgical ward.

Adult↗
PubMed1999

Comparison of three methods of microsatellite detection.

Examination of microsatellites is frequent in the diagnosis of cancer. Microsatellites are repeat DNA sequences scattered throughout the human genome. These repeat regions are very frequent and highly polymorphic elements. In this study we focus on dinucleotide repeats. We compared three different methods for the detection of microsatellites: use of the ABI Prism 377 fluorescence sequencer, autoradiography and silver-stained gels. DNA was extracted from various clinical samples and amplified by different polymerase chain reaction (PCR) protocols. DNA from normal and tumor tissues was analysed using each method. The fluorescence method was more sensitive than the two other methods; however, this technology is very expensive. It seems possible, when examining microsatellites on a low budget, to avoid radioactivity by using silver-stained gels as an alternative. In conclusion, we observed identical results when comparing autoradiography with the fluorescence technique. However, we observed variability in the results when interpreting a single locus comparing silver staining with autoradiography and the fluorescence technique. Classification of the tumors based on several microsatellite loci was always identical.

Autoradiography↗
PubMed1999

Effect of oxygen on tachycardia and arterial oxygen saturation during colonoscopy.

OBJECTIVE: To evaluate the effect of supplementary oxygen on heart rate and arterial oxygen saturation during colonoscopy. DESIGN: Controlled study. SETTING: Two university hospitals, Denmark. SUBJECTS: 40 patients having colonoscopy. INTERVENTIONS: 20 patients were given supplementary oxygen through nasal prongs (2 L/min), and 20 patients breathed room air during colonoscopy. All patients were given conscious sedation and were monitored with a pulse oximeter during colonoscopy. MAIN OUTCOME MEASURES: Tachycardia (pulse rate>100 min(-1)) and arterial oxygen desaturation (SpO2<90%) during colonoscopy. RESULTS: There were no differences in the incidence of tachycardia or mean heart rate during endoscopy between the two groups, and no patient developed symptomatic cardiac arrhythmias or hypotensive episodes. 10 patients in the room air compared with none in the oxygen treatment group (p = 0.0004) had one or more episodes during which arterial oxygen saturation fell below 90% during colonoscopy, and mean oxygen saturation was higher in the oxygen treatment group than in the room air group (p < 0.001). No clinical complications occurred in either group. CONCLUSION: Hypoxaemia and tachycardia are common during routine colonoscopy. The use of supplemental oxygen prevented hypoxaemia, but had no significant effect on heart rate.

Adult↗