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Biomedical subjects

H Hansen

Publications and source records attributed to H Hansen.

At least 181 records · Page 10Linked to original sources
PubMed1985

Retention and clearance of C-11 palmitic acid in ischemic and reperfused canine myocardium.

Free fatty acids are the major energy source for cardiac muscle. Oxidation of fatty acid decreases or even ceases during ischemia. Its recovery after transient ischemia remains largely unexplored. Using intracoronary carbon-11 palmitic acid as a tracer of myocardial fatty acid metabolism in an open chest dog model, retention and clearance of tracer in myocardium were evaluated at control, during ischemia and after reperfusion following a 20 minute occlusion of the left anterior descending coronary artery. Myocardial C-11 time-activity curves were analyzed with biexponential curve-fitting routines yielding fractional distribution and clearance half-times of C-11 palmitic acid in myocardial tissue. In animals with permanent occlusion and intracoronary injection of C-11 palmitic acid distal to the occlusion site, the relative size and half-time of the early clearance curve component differed markedly from control values and did not change with ongoing ischemia. Conversely, in animals with only 20 minutes of coronary occlusion, the relative size of the early C-11 clearance phase was still significantly depressed at 20 and 90 minutes of reperfusion but returned to control level at 180 minutes. Tissue C-11 clearance half-times remained significantly prolonged throughout the reperfusion period. Regional function in reperfused myocardium monitored with ultrasonic crystals recovered slowly and was still less than control after 3 hours of reperfusion. The data indicate that after transient ischemia, myocardial fatty acid metabolism fails to recover immediately. Because the metabolic recovery occurs in parallel with recovery of regional function, C-11 palmitic acid in conjunction with positron tomography may be useful for studying regional fatty acid metabolism noninvasively after an ischemic injury, and may be helpful in identifying reversible tissue injury.

Animals↗
PubMed1985

Sustained regional abnormalities in cardiac metabolism after transient ischemia in the chronic dog model.

Positron emission tomography allows noninvasive assessment of myocardial blood flow and metabolism, and may aid in defining the extent and severity of an ischemic injury. This hypothesis was tested by studying, in chronically instrumented dogs, regional blood flow and metabolism during and after a 3 hour balloon occlusion of the left anterior descending coronary artery. The metabolic findings after ischemia were compared with the recovery of regional function over a 4 week period. N-13 ammonia was used as a blood flow tracer, and C-11 palmitic acid and F-18 deoxyglucose as tracers of fatty acid and glucose metabolism, respectively. Regional myocardial function was monitored with ultrasonic crystals implanted subendocardially. Regional function improved most between 24 hours and 1 week after reperfusion, but was still attenuated at 4 weeks. The slow functional recovery was paralleled by sustained metabolic abnormalities, reflected by segmentally delayed clearance of C-11 activity from myocardium and increased uptake of F-18 deoxyglucose. Absence of blood flow and C-11 palmitic acid uptake at 24 hours of reperfusion correlated with extensive necrosis as evidenced by histologic examination. Conversely, uptake of C-11 palmitic acid with delayed C-11 clearance and increased F-18 deoxyglucose accumulation identified reversibly injured tissue that subsequently recovered functionally and revealed little necrosis. Thus, recovery of metabolism after 3 hours of ischemia is slow in canine myocardium and paralleled by slow recovery of function. Metabolic indexes by positron tomography early after reperfusion can identify necrotic and reversibly injured tissue. Positron tomography may therefore aid in defining the extent and prognosis of an ischemic injury in patients undergoing reperfusion during evolving myocardial infarction.

Animals↗
PubMed1985

Experimental toothclenching in common migraine.

The effect of 30 min voluntary toothclenching was studied in 48 patients with common migraine, randomized in two groups. Group 1 performed low-level tension at 5% and group 2, high-level tension at 30% of the individual maximum, as judged by surface EMG from the temporal muscle. Pericranial muscle tenderness was evaluated by manual palpation and a four-point verbal scale. Headache, nausea, and soreness of the chewing muscles were scored on visual analogue scales. Although surface EMG, soreness, blood pressure, heart rate and difficulty in completing the toothclenching session all showed that group 2 patients were subjected to significantly higher levels of muscle tension than group 1 patients, headache developed equally often in both groups (63%). Headache was even more pronounced in group 1 (n.s.). Five patients in group 1 and none in group 2 developed an attack of migraine during the following 24 h. Pericranial muscle tenderness was unaffected by the experimental procedure. There was no significant correlation between headache intensity and pericranial muscle tenderness. Muscle ischemia, muscle "fatigue", and strain on muscle insertions are thus unlikely to cause attacks of common migraine.

Adult↗
PubMed1985

Quantitative measurement of myocardial blood flow with oxygen-15 water and positron computed tomography: an assessment of potential and problems.

An in vivo measurement technique using 15O water and positron CT for quantitation of myocardial blood flow (MBF) was investigated. A closed-chest dog model and NeuroECAT scanner were used in the study. The in vivo technique involves i.v. infusion of 15O water for a duration of 2-3 min. Oxygen-15 water radioactivity in myocardium was imaged with a NeuroECAT scanner for 10 min, starting at the time of tracer infusion. A separate scan following inhalation of 15O CO was obtained to label the blood pool and to help remove the contribution of radioactivity in the blood pool during the 15O water scans. The integrated projection technique was used for calculating MBF. The quantitative microsphere technique for measurement of MBF was performed along with the 15O water study to provide reference values, with which the MBF values by the in vivo technique was compared. Results of 12 experimental runs (in seven animals) show the in vivo technique with 15O water and positron CT can give quantitative flow images of myocardium. The in vivo positron CT measurement was found to correlate well (r = 0.93) with the in vitro values (by microspheres) over the flow range of 40 to 150 ml/min/100 g.

Animals↗
PubMed1985

[Analysis of very underweight newborn infants (less than 1,500 g) 1972-1982. Epidemiologic aspects, labor presentation, position and adjustment, method of delivery and mortality].

Infants with a very low birthweight (less than 1500 g) have a fundamental influence on perinatal mortality and mortality of babies up to one year also nowadays. The epidemiological role of different signs of risk in the context of the birth of these children is presented. The total mortality of the infants with a very low birthweight (less than 1500 g) was 64,4%. Usually there were combinations of factors, which caused the death of the infants. Complications of secundinae, immaturity and malformations were the substantial factors of lethality of the stillbirths. At the mortality of babies there were intracranial bleedings and immaturity (less than 1000 g, less than 28 completed weeks of pregnancy) in the foreground of the causes of death.

Extraction, Obstetrical↗
PubMed1984

[Principles and results of narrow rectum continence resection in cancer].

The special anatomy of the "Rectum-Grenzlamellen" is the reason for justification to carry out a curative sphincter-preserving resection in carefully selected cases. In a small segment just above the pelvic floor muscles there are not any lymphnodes, when the lateral ligaments are divided and the rectum is thoroughly mobilized from the sacral concavity and stretched. The length of rectum below the tumor measured on fixed pinned-out pathologic specimens was about 2 cm. The local recurrences were 6% of 196 cases. The 5-year survival rate of this low restorative resection at St. Marks Hospital was excellent. These results suggest that a margin about 2 cm below a rectal carcinoma does not affect survival or local recurrence adversely.

Fecal Incontinence↗
PubMed1984

Establishment of a near-tetraploid B-cell lymphoma line with duplication of the 8;14 translocation.

The neoplastic cells of a patient with diffuse histiocytic lymphoma were grown in three systems: Soft agar, liquid culture, and by heterotransplantation into the nude mouse. In each case, the growing cells were shown to bear the same immunoglobulin heavy and light chain type as the original neoplastic cells (IgM-lambda). In both the liquid culture and nude mouse heterotransplant tumors, karyotypic analysis revealed the presence of pseudodiploid and near-tetraploid metaphases bearing one and two copies of an 8;14 translocation, respectively. From the liquid culture separate clones of pseudodiploid and near-tetraploid cells were isolated in soft agar, and separate cell lines SK-DHL2A and SK-DHL2B were established. Studies comparing the proliferative characteristics of the two lines showed no difference in cell population doubling time or clonigenicity in soft agar. Hence, the presence of two copies of the translocated material did not confer a proliferative advantage on cells containing it. Theses lines may be valuable in future studies of cell proliferation and oncogenesis in the human immune system.

Adult↗
PubMed1984

Cardiac emission computed tomography: underestimation of regional tracer concentrations due to wall motion abnormalities.

Possible effects of regional wall motion abnormalities on apparent regional myocardial tracer concentrations on emission tomographic images were evaluated in six open chest dogs. Each dog was studied twice: In Run 1, 13N ammonia and microspheres were injected during a 6 min coronary occlusion, and serial images acquired by positron emission tomography during occlusion and reperfusion. In Run 2, 1 h later, 13N ammonia and microspheres were reinjected at control, and serial images recorded at control, during a repeat 6 min coronary occlusion, and after reperfusion. Segmental function was monitored with ultrasonic crystals, and 13N tissue concentrations determined in vivo from the tomographic images and postmortem by well counting. In Run 1, fractional shortening in ischemic segments fell by 89 +/- 16% SD from control. The ischemic versus control segment ratio for 13N activity concentrations averaged 0.29 +/- 0.08 and for microspheres 0.20 +/- 0.15. In Run 2 the ischemic versus control segment ratio was at control 0.77 +/- 0.12 for 13N tissue activity and 0.85 +/- 0.07 for microspheres. Fractional shortening fell during occlusion by 131 +/- 29% from control, returned to control early, and fell again by 11 +/- 16% late during reperfusion. These changes were paralleled by changes in apparent regional 13N tissue concentrations of the prelabeled myocardium. Compared with control, they were 37 +/- 9% lower during occlusion and rose to 94 +/- 20% early and to 89 +/- 16% at control late during reperfusion. In vitro determined tissue concentration ratios of ischemic to control myocardium were similar for 13N and microsphere activity (0.83 and 0.85), which ruled out loss of 13N ammonia from tissue during occlusion or reperfusion. Our results indicate that regional wall motion abnormalities cause artifactual segmental defects in tracer concentrations on emission tomographic images of the heart, which must be considered for qualitative and quantitative analysis of regional tracer tissue concentrations.

Ammonia↗
PubMed1983

[Pharmacokinetics of ketoprofen in patients with renal failure].

Pharmacokinetics of ketoprofen were studied in five patients with more or less severe renal failure. Results were compared to those recorded in seven healthy volunteers. The degree of renal failure was evaluated by determining creatinine clearance. Ketoprofen was assayed by mass fragmentometry. As expected, results clearly show that the half-life of ketoprofen is prolonged in patients with renal failure. Duration of half-life is positively correlated with severity of renal failure.

Creatinine↗
PubMed1983

Transperineal 125iodine seed implantation in prostatic cancer guided by transrectal ultrasonography.

A new method is described for precise transperineal insertion of radioactive 125iodine seeds in patients with prostatic cancer. The procedure is done under transrectal ultrasonography guidance using a special multichannel puncture attachment and a simple, efficient insertion technique. The advantages of the method are 1) the patients are spared the inconvenience and risk of an operation, 2) improved dose calculations are possible, and 3) seed application is easy and more precise than by the conventional operative free-hand technique.

Brachytherapy↗
PubMed1983

Arthroscopy of the knee. An analysis of 588 consecutive knee arthroscopies.

In a consecutive study of 588 knee arthroscopies, the accuracy of the clinical and arthroscopical diagnosis is evaluated by means of the diagnostic specificity and sensitivity. The investigation includes a number of orthopaedic knee disorders, and it is shown that arthroscopy gives a substantial increase in the diagnostic accuracy. Follow-up examination of the non operated patients showed that surgery was avoided in 19 per cent of the patients, in whom surgery was indicated by clinical diagnosis. It is concluded that arthroscopy is a safe and valuable procedure in the diagnosis of knee disorders, and the best method to avoid unnecessary surgery.

Adolescent↗
PubMed1983

Role of chemotherapy in small cell lung cancer: a consensus report of the International Association for the Study of Lung Cancer workshop.

Many studies in small cell carcinoma of the lung (SCCL) have demonstrated a high response rate and a potential for cure in a subset of patients. Combination chemotherapy, the cornerstone of all treatment for SCCL, can produce up to 10% long-term, disease-free survival among all patients with SCCL and greater than or equal to 20% survival among patients who present with limited disease. Significant improvements in survival have occurred in all stages of disease, and further investigative efforts are necessary to improve the complete remission rate, the duration of response, and the percentage of long-term, disease-free survivors. The current report, based on the workshop on SCCL held in Ireland under the auspices of the International Association for the Study of Lung Cancer, reviews the current state of the art for chemotherapy and presents potential future directions.

Antineoplastic Agents↗
PubMed1983

[Comparative histologic studies following esophageal varices sclerosing with different substances].

Sclerosing varices of the lower esophagus by endoscopic injection of phenol-peanut oil or ethoxysclerol into the submucosal tissue induces inflammatory changes of varying degree. The process of inflammation leads to formation of connective tissue surrounding and protecting the varices, or to obliteration of these vessels. Phenol-peanut-oil induces a rather mild inflammatory process which contains many macrophages and runs a slow course, leading to fibrosis and sclerosis without complications worth mentioning. Ethoxysclerol on the other hand can induce suppurating, almost phlegmonous inflammation; complications like mediastinitis and pleural exsudates are definitively more common than after injection of phenol-peanut oil. Life threatening situations and death may occur after previous treatment by balloon compression and subsequent sclerosing procedures. Therefore, treatment of esophageal varices by sclerosing procedures should only be done, if the esophageal wall has not been altered by mechanical therapeutic measures.

Esophageal and Gastric Varices↗