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Biomedical subjects

G van Dijk

Publications and source records attributed to G van Dijk.

47 records · Page 3Linked to original sources
PubMed1993

Influence of peri-arterial hepatic denervation on the glycemic response to exercise in rats.

Exercise is known to increase hepatic glucose production. Previous studies have suggested that the sympathetic nerves only marginally contribute to this process. This study examined whether increased catecholamine response or increased adrenoceptor sensitivity might have affected previous results showing no effect of hepatic denervation on the increased hepatic glucose production during exercise. Hepatic sympathetic denervated rats, sham-operated rats and control rats were forced to swim against a counter current for 15 minutes. Denervations and sham operations were performed 9 days prior to swimming. The results show that denervation did not affect the changes in levels of blood glucose, plasma FFA, and catecholamines before, during and after swimming. Furthermore, hepatic adrenoceptor sensitivity was not altered in denervated rats, since intravenous infusions of epinephrine (20 ng/min) and norepinephrine (50 ng/min) similarly changed blood glucose and plasma FFA levels in liver-denervated, sham-operated and control rats. Thus, the increase in blood glucose levels during intravenous infusion of epinephrine and norepinephrine in the respective groups was 1.2 +/- 0.3 and 1.0 +/- 0.3 mmol/l (liver-denervated rats), 1.6 +/- 0.4 and 0.7 +/- 0.3 mmol/l (sham-operated rats) and 1.3 +/- 0.3 and 0.8 +/- 0.3 mmol/l (control rats), respectively. After adrenodemedullation, however, the rise of glucose levels during swimming in liver-denervated and control rats was completely abolished. Thus, the glucose response to swimming with and without adrenodemullation was 0.1 +/- 0.4 and 1.7 +/- 0.4 mmol/l in liver-denervated rats (P < 0.01) and -0.2 +/- 0.4 and 2.2 +/- 0.2 mmol/l in control rats (P < 0.001), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1992

On-line oxygen uptake measurement (VO2): a computer feed-back controlled rebreathing circuit for long term oxygen uptake registration.

A totally closed feed back controlled anesthesia- and ventilation circuit has been developed feasible to be applied for artificial ventilation with tidal volumes as low as 5 ml at a rate of up to 60/min and for spontaneous ventilation with on-line measurement of physiological lung parameters (pressure, volume, flow). Oxygen inflow is regulated via actual-set value comparison, oxygen inflow is measured and recorded on-line (= oxygen uptake by the connected subject). On-line oxygen uptake (consumption) measurement furnishes a valuable, so far not available parameter to monitor changes in the oxygen transport chain to the tissue and to register physiological oxygen consumption values and derangement of metabolism. First results show that total body oxygen consumption of man in rest is lower than so far expected in the high weight and body surface area groups and that oxygen consumption is decreasing with length and age. Metabolic derangements such as in developing hyperthermia crisis are noticed in a very early stage when therapy is still possible before severe damage has occurred.

Adult↗
PubMed1991

[A computer-controlled closed circle system for ventilation during anesthesia and intensive care and its possibilities for patient monitoring].

A computer feed back controlled anaesthesia- and intensive care ventilator has been developed with on-line and separate lung function measurement. The system design is built on the principle of a totally closed circuit (closed rebreathing respirometer) and an inspiratory "high flow", the gas being rotated through the closed circuit unidirectionally by a blower with 70 l/min. Ventilation is performed by metal membranes freely movable in membrane chambers with an internal part included into the closed circuit and an external part connected to pressurized air controlling inspiratory valves expiratory valves. The electronic valves are software controlled by the computer to exactly perform the desired preset ventilatory mode. Membrane movement are on-line measured capacitively and transformed into respective flow and volume values, whereby the compressibility of the system gas (on-line pressure recording) is taken into account. Volatile anaesthetic gases are feed back controlled to preset end expiratory values (MAC-controlled anaesthesia), circuit volume is maintained by N20-addition and oxygen is added to maintain the desired present inspiratory concentration measured with paramagnetic oxygen sensors. Ergonometric aspects led to the triangular from of the new anaesthesia and intensive care ventilator with the controlling service screen turnable to all three sides of the ventilator (high flexibility of the user) and all necessary equipment and material included into the "Anaesthesia workstation". All measured and present parameters are continuously displayed on the service (computer) screen and entered into the computer-memory in minute cycles with a memory capacity of 75 h anaesthesia. At any desired moment the memorized values can be transferred to IBM-compatible disc systems for storage or into the respective data management systems, thus at the end of anaesthesia, at the end of the working day or at the end of the week.

Anesthesia, Closed-Circuit↗
PubMed1991

[Multidisciplinary patient care in facial prosthetics].

The aim of maxillofacial prosthetics is the treatment of patients with head and neck diseases in a multidisciplinary way. The treatment of patients with a facial defect should be based on a close cooperation between maxillofacial prosthetist and MFP technician. The rehabilitation process and the specific role of each is described.

Dental Technicians↗
PubMed1989

Effects of topically applied glucocorticosteroids on patch test responses and recruitment of inflammatory cells in allergic contact dermatitis.

The effects of repeated topical application of a strong glucocorticosteroid (GCS) on patch test responses and the inflammatory infiltrate were studied in twenty nickel allergic patients. Patch test responses were strongly inhibited in 18 out of 20 patients. Immunohistochemical analysis revealed marked reductions in CD1+(T6+) Langerhans cells, activated inflammatory T cells and of mast cells in the skin. It is concluded that GCS suppress contact allergic responses by reduction, or functional inhibition of antigen presenting cells. The reduced number of mast cells release less vasoactive mediators, inhibiting recruitment of inflammatory cells.

Administration, Topical↗
PubMed1989

[Maxillofacial prosthodontics. Its possibilities and limitations].

The maxillofacial prosthodontist acts primarily as a member of the head and neck oncology team. Using special methods and techniques, and more or less specific materials, speech, chewing, swallowing and facial expression are to be regained as good as possible. Due to the complexity of several orofacial functions, surgical or prosthodontic rehabilitation cannot always be accomplished.

Dentures↗
PubMed1985

Mucopolysaccharides in suspensions of Treponema pallidum extracted from infected rabbit testes.

The amount and nature of mucopolysaccharides present in extraction fluids routinely obtained in the isolation procedure of Treponema pallidum from infected rabbit testes was investigated. The mean quantity of mucopolysaccharides extracted from both testes of groups of 10 rabbits was 3.09 mg after infection for seven days and 26.88 mg after infection for 12 days, while from the testes of uninfected rabbits a mean of 0.42 mg was obtained. On electrophoresis the isolated mucopolysaccharides showed only one single band with the migration characteristics of hyaluronic acid. This band disappeared completely after pretreatment with hyaluronidase from bovine testes, which showed that during infection with T pallidum increasing amounts of hyaluronic acid accumulate. They can, at least in part, be extracted by a gentle extraction procedure, suggesting that this material binds loosely. The amount of hyaluronic acid isolated 12 days after infection showed positive correlations with the wet weight of testes as well as the number of treponemes isolated; seven days after infection such correlations were not present.

Animals↗
PubMedDate not supplied

Indications for extra-oral implantology.

In this paper, the general indications for implantology for facial prosthesis in the maxillofacial bones are elaborated. Information from both the literature and our own surgical experience emphasizes that only specific locations of the facial bones and skull are suitable for implant fixtures. Careful indication and surgery are required for patients who were exposed to radiotherapy. The success of maxillofacial rehabilitation depends on multidisciplinary cooperation.

Ear, External↗