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Biomedical subjects

H Bakker

Publications and source records attributed to H Bakker.

At least 37 records · Page 2Linked to original sources
PubMed1995

Reduction of EGP-2-positive pulmonary metastases by bispecific-antibody-redirected T cells in an immunocompetent rat model.

Effectiveness of bispecific-monoclonal-antibody (BsMAb)-mediated cellular anti-tumour activity was evaluated in vitro and in vivo in relation to the additional need for T-cell activation in a new immunocompetent rat tumour model. L37 tumour cells, derived from a squamous-cell carcinoma of the lung of Wag/Rij rats, were transfected with the cDNA coding for the human 38-kDa transmembrane pan-carcinoma-associated antigen EGP-2. Intravenous inoculation of EGP-2-positive L37 cells resulted in a rapid outgrowth of EGP-2-positive tumour nodules in the lungs. A BsMAb BIS-19, recognizing EGP-2 on the transfected tumour cells and the T-cell receptor of the rat, was made and allowed specific lysis of EGP-2-transfected L37 tumour cells by activated rat T lymphocytes in vitro. In vivo T-cell activation, assessed by up-regulation of IL-2-receptor expression, could be induced by daily injection of rat rIL-2. Intravenous treatment of tumour-bearing EGP-2-positive L37 tumour with BIS-19 together with rat rIL-2 resulted in almost complete disappearance of established tumour. In contrast, animals treated with BIS-19 alone, IL-2 alone or a combination of anti-EGP-2, anti-TcR and IL-2 showed much less or no tumour reduction. These results show effectiveness of systemic treatment with BsMAbs to induce anti-tumour activity in established tumours. Immune activation prior to or during treatment with BsMAbs, as achieved with IL-2, appears to be a prerequisite for successful treatment.

Animals↗
PubMed1994

A Lymnaea stagnalis gene, with sequence similarity to that of mammalian beta 1-->4-galactosyltransferases, encodes a novel UDP-GlcNAc:GlcNAc beta-R beta 1-->4-N-acetylglucosaminyltransferase.

A cDNA encoding a novel glycosyltransferase, that may be involved in a variant pathway for the synthesis of complex type oligosaccharide chains, was cloned from the pond snail Lymnaea stagnalis. By heterologous hybridization, using bovine beta 1-->4-galactosyltransferase cDNA as probe, a genomic clone from a snail library was isolated. This genomic clone was subsequently used to clone the corresponding cDNA from a prostate gland library. The isolated cDNA encodes a polypeptide of 490 amino acids with a type II membrane protein topology typical for glycosyltransferases. The carboxyl-terminal part, encoding the putative catalytic domain, reveals considerable sequence similarity with the corresponding region of mammalian beta 1-->4-galactosyltransferases, suggesting an evolutionary relationship. Expression of this cDNA in COS cells and insect cells revealed that the encoded enzyme transfers GlcNAc, rather than Gal or GalNAc, from the corresponding nucleotide sugars to several beta-N-acetylglucosaminides. Structural characterization by 1H NMR spectroscopy of products formed in vitro demonstrated that the enzyme can be identified as a UDP-GlcNAc:GlcNAc beta-R beta 1-->4-N-acetylglucosaminyl-transferase. A new family of glycosyltransferases has hereby been discovered, consisting of enzymes that act on acceptor substrates with a terminal beta-linked GlcNAc residue and establish a beta 1-->4-linkage, but have a different nucleotide sugar requirement.

Amino Acid Sequence↗
PubMed1992

[Diabetic patients: no danger on the road].

The evaluation of the risk of traffic accidents among drivers with IDDM and the grounds for excluding them from a driver's license are topical issues, because the E.C. is issuing strict new guidelines. The risk of diabetic patients being involved in traffic accidents as reported in foreign studies and calculated from Dutch data, does not exceed that which is to be expected on account of the prevalence of DM. This justifies a flexible policy for the licensing of drivers with diabetes mellitus.

Accidents, Traffic↗
PubMed1992

[Revision consensus prevention and treatment decubitus].

The text of the Consensus Meetings Prevention and Treatment of Decubitus (pressure sores; 1985 and 1986 respectively) was adapted to current insights into pathogenesis and treatment. This adaptation was important since the costs of the prevention and treatment of decubitus are enormous and decubitus tends to occur more often since the population is growing older. The so called anti-decubitus devices were grouped in 3 categories: 1. polyether foam mattresses, placed on top of the standard hospital mattresses (merely in prevention and in treatment of patients less than 85 kg), 2. polyether foam mattresses with or without special surface layout or simple alternating pressure air mattresses, replacing the standard hospital mattress (especially in patients greater than 85 kg) and 3. special beds and bed systems as low-air-loss beds and air-fluidized beds (only on strict indications such as thoracic operations and intensive treatments). The clinical manifestations of decubitus were classified in 4 stages: non-blanching erythema (1), blister (2), superficial decubitus (3) and deep decubitus (4). The existence of another form of pressure sores was identified: decubitus originating from operation or angiography tables, on which a deep necrosis develops, extending to form an abscess, erupting through the skin after 7-14 days. These ulcers are characterised by an impressive depth, usually to the underlying bones, but with vivid edges. The development of these sores is prevented in most cases by using a category 1 device on the tables mentioned.(ABSTRACT TRUNCATED AT 250 WORDS)

Bedding and Linens↗
PubMed1992

Effect of chorionic villus sampling on utilization of prenatal diagnosis in women of advanced maternal age.

The effect of the introduction of chorionic villus sampling on the utilization rate of prenatal diagnosis in advanced maternal age was studied during the period 1 January 1985-1 January 1991. On the first of January 1985, the age limit for prenatal diagnosis in The Netherlands was lowered from 38 to 36 years of age. The overall uptake rate during the studied period increased significantly, but only because of the increased uptake rate in the group 36 and 37 years. In the maternal age group of 42 years and older, an uptake rate as low as 15.9% was established. This was mainly determined by the relatively high percentage (73.0%) of women from ethnic minorities in this age group. The number of CVS procedures increased significantly during the study period, but the utilization rate was not influenced, since the number of amniocenteses decreased accordingly. An increase in acceptability of prenatal diagnosis by women of advanced maternal age due to early testing and early termination of pregnancy could not be substantiated in the present study.

Adult↗
PubMed1992

The dose-response and time-effect relationships of intrathecal bupivacaine in rats. The influence of epinephrine and pH.

The present study defined the dose-response relationship of intrathecally injected bupivacaine in rats. The effect was a quantified drug-induced and graded reduction in the magnitude of the withdrawal reflexes elicited by transcutaneous electrical stimulation. Intrathecal epinephrine reduced the magnitude of the withdrawal reflexes. The combination of epinephrine and bupivacaine resulted in a dose-response relationship different from that of bupivacaine alone, and the combination was more effective than bupivacaine alone. The intrathecal combinations of bupivacaine and 25 micrograms of the alpha 2-adrenergic antagonist idazoxan had an effect not different from that of bupivacaine alone, but the duration of effect was shorter. The dose-response relationship of bupivacaine was not different whether the pH of the solution was 4.4 or 6.1. The results concerning the effect as a function of time confirm those of earlier studies: 1) the duration of effect depends on the dose of bupivacaine; 2) epinephrine protracts the duration of effect; 3) the pH is of no relevance. Thermal tests for nociception showed that antinociception outlasted motor symptoms. Epinephrine enhanced this effect of bupivacaine, but did not change the duration of motor impairment.

Animals↗