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Biomedical subjects

K E Jensen

Publications and source records attributed to K E Jensen.

At least 19 recordsLinked to original sources

[The venereological profile in Godthab District Venereal Clinic, Nuuk, Grønland. A 3-month study in 1991].

A total of 803 patients participated in a consecutive review of the disease pattern concerning venereal diseases. The investigation took place in the Clinic for Venereal Diseases in Nuuk/Godthåb during a period of three months. Less than half of the contacts were on account of symptoms of genital infection. One fifth of the patients had been summoned for partner control. A corresponding proportion felt well and had not been exposed to any known risk of infection. Chlamydia trachomatis was demonstrated in 19% and gonorrhoea in 10%. Among the asymptomatic persons, 16% were found to be Chlamydia positive and 0.6% gonococcal positive. Syphilis was demonstrated in one man and one woman. One man was known to be HIV-positive and two contacts of this patient were found to be negative but seroconversion occurred subsequently in both cases. Vaginitis and bacterial vaginosis were found in 38% of the women. In over one third (39%), no clinical or microbiological evidence of genital infection was found. Early diagnosis, treatment, information and tracing of contacts are still the cardinal principles in the combat of venereal diseases in Greenland.

Chlamydia Infections

Postoperative pain and nausea after laparoscopic cholecystectomy.

Postoperative discomfort following cholecystectomy has diminished considerably since laparoscopic surgery was introduced. This study assessed the degree of postoperative pain and nausea when, during the operation, the trocar sites had been infiltrated with bupivacaine and antiemetics (ondansetron) had been administered. Postoperative pain intensity was moderate as 20% of the patients were managed without any opiates postoperatively and 88% did not require any opiates after discharge from the recovery room. Postoperative nausea and vomiting is known to be a problem that occasionally has been reported to delay discharge from the hospital. A single dose of ondansetron at the end of the operation seems to reduce postoperative nausea effectively. Two-thirds of the patients had no complaints of nausea, and the majority of the remainder experienced only mild and transitory nausea. We recommend that stab-wound sites be infiltrated with local anesthetics and that antiemetics be administered at the end of the operation.

Adult

31P magnetic resonance spectroscopy of skeletal muscle in patients with fibromyalgia.

31Phosphorous nuclear magnetic resonance (31P NMR) spectroscopy of painful calf muscle was performed in 12 patients with fibromyalgia (FS) and 7 healthy subjects during rest, aerobic and anaerobic exercising conditions, and postexercise recovery. Ratios of inorganic phosphate and creatinine phosphate (Pi/PCr) and pH were calculated from the collected 31P NMR spectra. Resting values of Pi/PCr were normal in the patients. Patients delivered only 49% of the muscle power of the controls (p = 0.005). Patients and controls had similar rates of Pi/PCr and pH changes during work and recovery. The controls were able to change their Pi/PCr and pH more than the patients, due to the greater workload reached. However, statistical significance was reached only for the anaerobic static exercise (p = 0.003). It was concluded that patients with FS have a reduced voluntary capacity for work, but normal biochemical response to work and recovery.

Adult

[Experience from the first year of treatment of renal calculi with extracorporeal piezoelectric shockwave lithotripsy].

The experience of the first year with piezoelectric extracorporeal lithotripsy is described. One hundred and eighty-eight patients commenced treatment of 194 renoureteric stone units (a total of 328 stones). Twelve per cent required analgesics during therapy. The median number of treatments was two (1-6) and median number of shock waves 4,200 (450-24,606). One hundred and twenty-three stone units had concluded treatment and control schedules at the follow up end date. After six months, 59% of the stone units were stone-free, while 17% had residual fragments up to 2 mm, and additional 15% had residual fragments between 2 and 6 mm. Only few and insignificant complications were observed. Extracorporeal shock wave lithotripsy by the Wolf Piezolith 2300 is a well-tolerated, effective, relative painless and not complicated treatment of renal stones, and an important part of modern treatment of staghorn- and ureteric stones.

Adult

A simple calf muscle ergometer for use in a standard whole-body MR scanner.

A calf muscle ergometer, designed for use in a standard whole-body MR scanner, is described. The instrument allows isotonic or isometric calf muscle exercise over a continuous range of work loads from 0 to individual maximum work output. Work output may be recorded on a strip chart recorder. A sound encoding provides an effective guidance for the subject tested to accurately reproduce his performance in each contraction cycle at a given work load. The FID recording may be triggered from the ergometer at any point during the contraction cycle. Nonmetal materials are used for the instrument construction in order to eliminate potentially disturbing eddy currents. The force resistance of the ergometer is obtained by a combined hydraulic-pneumatic system, which is loaded by coupling to an outside source of compressed air equipped with a suitable pressure regulator. When varying the time of data sampling within a repeated 6-s contraction cycle it was found that the recorded Pi/PCr ratio remained essentially constant at low and moderate work loads. However, at work loads at or above 70% of individual Vmax a pronounced dependence of the time of sampling with the contraction cycle was observed.

Equipment Design

Changes in T1 relaxation processes in the bone marrow following treatment in children with acute lymphoblastic leukemia. A magnetic resonance imaging study.

Magnetic resonance imaging (MRI) and T1 relaxation time measurements of the vertebral bone marrow were performed in 11 children with acute lymphoblastic leukemia (ALL) at diagnosis. Nine of the children were re-examined after chemotherapeutic treatment. The results were compared with histological data from bone marrow biopsies obtained in close association to the MR examinations. Ten age matched children were examined as a control group. A 1.5 Tesla whole body scanner was used for the measurements. The pretreatment T1 relaxation times of the bone marrow were significantly prolonged, compared to the age matched controls. After chemotherapy the T1 relaxation times of the children with ALL decreased significantly towards or into the normal range. A significant correlation was found between the T1 relaxation time and the content of malignant blast cells in the bone marrow.

Adolescent

Localized in vivo proton spectroscopy of the bone marrow in patients with leukemia.

Volume selective magnetic resonance (MR) proton spectroscopy was used to investigate the haemopoietic (iliac bone) and fatty bone marrow (tibia) in patients with leukemia and polycythaemia vera. Selective measurements of the relaxation times T1 and T2 for the "water" and "fat" resonances in the bone marrow spectra were performed. Nine patients with acute leukemia and three patients with chronic leukemia were examined at diagnosis. Three patients with acute leukemia in remission were also examined. Five of the leukemic patients had follow-up examinations performed in relation to chemotherapeutic treatment. Nine patients with polycythaemia vera and 21 normal control subjects were examined with identical methods for comparison. All patients had bone marrow biopsies performed prior to every MR examination. Significant differences could be detected in the spectral patterns from iliac bone marrow in patients with leukemia at diagnosis compared to the healthy normal controls. The "relative water content" was increased in the iliac bone marrow spectra of the leukemic patients compared to the normal subjects, which indicates an increase in the amount of haemopoietic tissue and a corresponding decrease in marrow fat content. The T1 relaxation times of the "water" resonance in the spectra from the iliac bone marrow of the leukemic patients were significantly prolonged at diagnosis, compared to the normal controls and the patients with polycythaemia vera. After chemotherapeutic induction of remission, the spectra from the iliac bone marrow in the patients with leukemia resembled normal spectra. Four leukemic patients had abnormal spectra from the tibial bone marrow and one patient showed early changes in tibial marrow during chemotherapeutic treatment, before any major changes could be detected in the iliac bone marrow.

Bone Marrow

Effects of recombinant human erythropoietin on the haemopoietic bone marrow monitored by magnetic resonance spectroscopy in patients with end-stage renal disease.

Volume selective magnetic resonance (MR) proton spectroscopy was used to investigate changes in the haemopoietic bone marrow in patients with end-stage renal disease undergoing treatment with recombinant human erythropoietin (rHuEPO). Significant changes could be detected in the spectra 14 days after the beginning of treatment, before any response was seen in the haemoglobin concentration of peripheral blood. The spectral changes indicate an alteration in cellular composition of haemopoietic bone marrow with an increase in the amount of haemopoietic active tissue. One patient showed a major change in the spectrum four days after treatment began, indicating that MR spectroscopy may detect early changes in the cellular composition of the bone marrow. This noninvasive method may be useful in evaluating treatment effects of recombinant human haemopoietic growth factors in the bone marrow, as well as investigating bone marrow response from different modes of rHuEPO administration.

Adult

MR pulse sequences for selective relaxation time measurements: a phantom study.

The accuracy of relaxation time measurements of spectroscopic inversion recovery and CPMG multi-echo pulse sequences together with ISIS and stimulated echo-pulse methods have been tested on a reference phantom (test object no. 5, of the EEC Concerted Research Project). For the measurements a Siemens Magnetom wholebody magnetic resonance scanner operating at 1.5 Tesla was used. For comparison six imaging pulse sequences for relaxation time measurements were tested on the same phantom. The spectroscopic pulse sequences all had an accuracy better than 10% of the reference values.

Humans

Improved energy kinetics following high protein diet in McArdle's syndrome. A 31P magnetic resonance spectroscopy study.

A patient with McArdle's syndrome was examined using bicycle ergometry and 31P NMR spectroscopy during exercise. The patients working capacity was approximately half the expected capacity of controls. Muscle energy kinetics improved significantly during intravenous glucose infusion and after 6 weeks of high protein diet. During intravenous infusion of amino acids, no changes in working capacity could be detected. No decrease was seen in intracellular muscle pH during aerobic exercise. A significant decrease in muscle pH during aerobic exercise was detected in all controls.

Adult

Magnetic resonance imaging of the bone marrow in patients with acute leukemia during and after chemotherapy. Changes in T1 relaxation.

Twenty-seven patients with acute leukemia were examined at the time of diagnosis with MR imaging and in vivo T1 relaxation time measurements of the hemopoietic bone marrow. A 1.5 T whole body magnetic resonance scanner was used. Twenty of the patients had follow-up examinations in relation to chemotherapy. Bone marrow biopsies from the posterior iliac crest were obtained within a short time interval of all MR examinations. At the time of diagnosis, T1 relaxation times were increased significantly in all the leukemic patients, compared with 24 age-matched controls. A decrease in T1 relaxation time towards or into the normal range was observed in 10 patients who obtained remission. The T1 relaxation time remained prolonged in 6 patients who failed to obtain remission during chemotherapy. Four patients, who obtained remission with concomitant decrease of T1 values towards or into the normal range, also showed prolongation of T1 relaxation time in relation to leukemic relapse. The results indicate that changes observed in T1 relaxation times of the hemopoietic bone marrow in patients with acute leukemia reflect changes in disease activity, and, that serial measurements of T1 values may provide clinically useful information with the possibility for identification of residual disease in regions inaccessible for biopsy.

Adolescent

Magnetic resonance imaging of the bone marrow following treatment with recombinant human erythropoietin in patients with end-stage renal disease.

We used magnetic resonance imaging (MRI) to study vertebral bone marrow in hemodialysis patients during treatment with recombinant human erythropoietin (rHuEPO). We found changes in T1 relaxation times and image contrast within 14 days after starting treatment, before any response was seen in the hemoglobin concentration in peripheral blood. The increase in T1 relaxation times, together with earlier reported changes observed with localized magnetic resonance spectroscopy, indicate an alteration in cellular composition of the hemopoietic bone marrow with an increase in the amount of hemopoietic active tissue. MRI may be a useful, non-invasive way of evaluating bone marrow response to different modes of rHuEPO administration and dosage.

Anemia

Prolonged T1 relaxation of the hemopoietic bone marrow in patients with chronic leukemia.

Eleven patients with chronic leukemia (7 with chronic lymphocytic leukemia and 4 with chronic myeloid leukemia) were evaluated with magnetic resonance (MR) imaging and T1 relaxation time measurements by use of a 1.5 tesla whole body MR scanner. Bone marrow biopsies were obtained from the posterior iliac crest (within 72 hours of the MR examination) in order to provide data on bone marrow cellularity and differential counts. The patients with chronic leukemia all showed a significant prolongation of the T1 relaxation times compared with the normal range for hemopoietic bone marrow.

Adult

Neuronal pH regulation: constant normal intracellular pH is maintained in brain during low extracellular pH induced by acetazolamide--31P NMR study.

The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate and the phosphocreatine resonance frequencies was used for indirect assessment of the intracellular pH. The mean baseline intracellular pH was 7.05 +/- 0.04 (SD). The mean pH changes obtained at 15-min intervals within the first hour of acetazolamide administration were -0.03 +/- 0.04 (SD), -0.02 +/- 0.03 (SD), and 0.00 +/- 0.04 (SD), i.e., no statistically significant pH decrease was observed during the period where extracellular pH is known to drop markedly. Although several factors contribute to the lack of change of the intraneuronal pH, we will discuss that this observation in addition might suggest a direct intracerebral effect of acetazolamide.

Acetazolamide