Biomedical subjects

P E Visser

Publications and source records attributed to P E Visser.

4 recordsLinked to original sources

PubMed1994

Programming the microwave oven.

Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue, fluids and solids that are used in these preparatory techniques. In this paper we describe our accumulated experience with monitoring and controlling microwave-oven parameters with the help of a personal computer (PC). A specially designed microwave oven was used with an advanced temperature probe. The oven was connected to an IBM-compatible PC. This enabled us to analyze the quality of temperature control, and the relationship between displayed and actual temperature. We show that for microwave-transparent materials the addition of a microwave-absorbent plate to the material results in better temperature control.

Ethanol↗

PubMed1989

Microwave treatment of xenogeneic cartilage transplants.

Human rib cartilage was irradiated with microwaves according to six different methods and transplanted into rabbits. Untreated rib cartilage preserved in Cialit served as a control. After 12 and 40 wk of implantation, the microscopic appearance of these xenogeneic cartilage transplants was given a score in comparison with the transplants preserved in Cialit. The microwave treatment of the cartilage appeared to improve the results. The Cialit-preserved transplants showed progressive resorption by macrophages with central necrosis and fragmentation, which was not present in the microwave-treated grafts. Microwaves seem to stabilize the cartilage matrix and enhance the diffusion of fixatives. Irradiation in ethanol as an immersion fluid appeared to be the best method. The results of transplantation can benefit from the use of microwaves in the preservation of the cartilage. It is argued that, in addition, microwave irradiation might be used for inactivation of human immunodeficiency virus in human cartilage used for transplantation.

Animals↗

PubMed1986

The establishment of Plasmodium berghei in mosquitoes of a refractory and a susceptible line of Anopheles atroparvus.

The events between the ingestion of Plasmodium berghei-infected mouse blood and the establishment of the ookinetes in the epithelium of the midgut in refractory (R) and susceptible (S) Anopheles atroparvus are described. Simultaneously fed, fully engorged female mosquitoes were randomly assigned to dissection at 22, 28, 32, 48 h and 10 days (controls) after the infective feed (post-infection: p.i.). Serial transverse sections of 6 micron were cut. Every 10th section was studied. The maturation of ookinetes was monitored at 16, 19 and 22 h p.i. The infections in R and S mosquitoes developed similarly with regard to the maturation of ookinetes and the number of mature ookinetes in the lumen of the midgut. The semiquantitative evaluation of the envelopment of the food bolus by the peritrophic layer showed that this layer cannot function as a physical barrier against migrating ookinetes. In the midgut epithelium the number of ookinetes decreased significantly with time in both R and S mosquitoes, but a similar number of penetrations was recorded for both types of mosquito. In S mosquitoes maximal 1% of the ookinetes present in the midgut formed an oocyst. In both R and S mosquitoes a substantial loss of parasites was found, first in the lumen of the midgut and second after penetration of the midgut epithelium by the mature ookinetes. Relatively few parasites develop into oocysts in S, but hardly any do so in R individuals. The factors in control of refractoriness are likely to operate on early oocyst development.

Animals↗

PubMedDate not supplied

Histoprocessing with the microwave oven: an update.

This paper evaluates and extends the novel method of preparing tissue blocks for paraffin sections within 30 to 60 min, that was proposed in early 1985 in a paper by Boon et al. (1986). More than 2 years' additional experience and testing various microwave ovens has led to new protocols reported in this paper. Results are given of testing (i) an especially designed microwave oven for histoprocessing, (ii) microwavable reagents, (iii) processing larger numbers of specimens simultaneously, (iv) handling different types and sizes of tissue. It is concluded that effective temperature control offers substantial advantages. In addition, the possibilities of performing routine diagnostic pathology omitting formalin altogether are sketched.

Female↗