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Biomedical subjects

B Jessen

Publications and source records attributed to B Jessen.

At least 19 recordsLinked to original sources
PubMed2005

Increase in thyroid follicular cell tumors in nelfinavir-treated rats observed in a 2-year carcinogenicity study is consistent with a rat-specific mechanism of thyroid neoplasia.

The carcinogenic potential of nelfinavir mesylate (nelfinavir) was evaluated in a 2-year oral (gavage) study on Sprague-Dawley rats at dose levels of 0 (control), 0 (vehicle control), 100, 300 and 1000 mg/kg per day. At the end of the treatment, increased incidences of thyroid follicular cell hyperplasia and neoplasms were observed at 300 (males) and 1000 mg/kg per day (both sexes). There were no other treatment-related effects and no tumors at other sites. Results from previous studies indicated a number of effects in the liver and thyroid, as well as metabolic profiles that suggested nelfinavir might cause thyroid hyperplasia/neoplasia secondary to hormone imbalance by altering thyroid hormone disposition. To investigate this hypothesis, the effects of nelfinavir on gene expression in rat hepatocytes and liver slices (in vitro), thyroxine plasma clearance, and thyroid gland function were evaluated. Compared to controls, gene expression analyses demonstrated an increased expression of glucuronyltransferase (UDPGT) and CYP450 3A1 in nelfinavir-treated rat hepatocytes and liver slices. In rats treated with nelfinavir (1000 mg/kg per day) for 4 weeks, liver weights and centrilobular hepatocellular hypertrophy were increased and minimal to mild diffuse thyroid follicular cell hypertrophy and follicular cell hyperplasia were evident in the thyroid gland. Thyroid-stimulating hormone (TSH) levels were significantly increased (three-fold), while tri-iodothyronine (T3)/tetra-iodothyronine (T4) and reverse T3(rT3) levels were unchanged, indicating that a compensated state to maintain homeostasis of T3/T4 had been achieved. Plasma 125I-thyroxine clearance was increased and the plasma thyroxine AUC0-48 was decreased (24%) compared to control. In conclusion, these data indicate that thyroid neoplasms observed in the nelfinavir-treated rats were secondary to thyroid hormone imbalance. Increased thyroxine clearance contributes to the effects of nelfinavir on thyroid gland function and is probably a result of UDPGT induction that leads to elevated TSH levels in the rat and eventual thyroid neoplasia. These results are consistent with a well-recognized rat-specific mechanism for thyroid neoplasms.

Adenocarcinoma, Follicular↗
PubMed1994

[Treatment of carbon monoxide poisoning. Background and guidelines for oxygen therapy].

Treatment of carbon monoxide (CO) poisoning is still controversial. Standard treatment is pure oxygen either by means of a nasal catheter or oral-facial mask (normobaric oxygen treatment). Since 1960, hyperbaric oxygen (HBO) therapy has been applied in various centres, i.e. treatment in hyperbaric chambers with 100% O2 at 2-2.8 bars absolute pressure. Physically dissolved oxygen at this pressure is sufficient to maintain normal life functions at rest. HBO causes fast reoxygenation of tissues and accelerates the elimination of CO. In this paper, two cases treated with hyperbaric oxygen are reported. Aetiology, pathogenesis and possible sequelae of CO poisoning are reviewed. It is recommended, that all CO-victims, who have been or are unconscious at admission to the emergency ward, should be treated with HBO. In spite of there being comprehensive clinical literature concerning treatment of CO poisoning, there is still a great need for clinically controlled studies.

Aged↗
PubMed1984

Motion sickness susceptibility in student navigators.

Identification of individuals highly susceptible to motion sickness could be of significant benefit in managing flying personnel in training. Several studies in the past four decades with this end have been primarily aimed at pilot trainees. The following study is a prospective evaluation of airsickness in Air Force navigation students. Motion Sickness Questionnaires and Minnesota Multiphasic Personality Inventories were given to the students at the beginning of navigator training. Airsickness was assessed by means of questionnaires and evaluation by a flight surgeon. Motion sickness among navigation trainees was found to be quite common. However, prediction of susceptible individuals by methods used was not reliable. Further investigation of airsickness susceptibility in navigation students by means of physiologic techniques is suggested.

Adult↗
PubMed1980

A control, double-blind comparison of mepivacaine injection versus saline injection for myofascial pain.

In a double-blind study 28 patients with acute, localised muscle pain received four local injections of mepivacaine 0.5%, and 25 patients with the same type of pain received local injections of an equivalent volume of physiological saline. The group receiving saline tended to have more relief of pain, especially after the first injection. The results thus show that pain relief is not due merely to the local anaesthetic. The study therefore raises questions about the mechanism by which local injections into muscle relieves pain, since there is the possibility that a similar effect might also be achieved by merely inserting a needle into the trigger point. Physiological saline is considered to be a more appropriate fluid for injection therapy than local anaesthetics since it is less likely to produce side-effects.

Clinical Trials as Topic↗
PubMed1976

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.

Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Chromatography, Gas↗