Biomedical subjects

G P Loots

Publications and source records attributed to G P Loots.

7 recordsLinked to original sources

PubMed1994

Electron microscopic study of human sperm membrane isolation.

OBJECT: Our purpose was to isolated pure, homogeneous human sperm membranes, free of cellular contaminants. METHODS: Donor semen samples collected after masturbation were stored at -70 degrees C and eventually pooled. Each attempt at sperm membrane isolation required 800 x 10(6) spermatozoa which were sonicated by ultrasound (40% output; Vibra Cell). The effect of sonication time (3 x 5, 3 x 15, and 180 sec) on membrane isolation was investigated. Sonicated samples were centrifuged (500 g, 5 min) and the supernatant was pipetted off. The supernatant of the centrifuged sample was layered on either a sucrose cushion (supernatant on 1.6 M sucrose) or a discontinuous sucrose gradient and centrifuged (100,000 g, 1 hr). Contents of supernatants of sonicated samples and fractions (sucrose interfaces) were then fixed in 1.0% tannic acid and 2.5% buffered glutaraldehyde and examined electron microscopically using standard procedures. RESULTS: (1) The optimal sonification time was found to be 3 x 15 sec. (2) Membrane isolation using a sucrose cushion was found to be inadequate, showing significant cellular contamination. (3) Sperm membrane isolation from the sucrose interface between 0.75 and 1.05 M sucrose was found to be most effective. CONCLUSION: The advantage of this method is its simplicity. The drawback of this method is the large number of spermatozoa required for membrane purification.

Cell Fractionation↗

PubMed1991

Microcirculation of the rat omentum studied by means of corrosion casts.

A study of the microvasculature of the omentum using corrosion casts was undertaken. The object was to supply information regarding the morphology of the three-dimensional structure of the microvasculature, information which may be valuable in understanding the functions of the omentum. Corrosion casts of rat omenta were prepared and studied. Characteristic glomerular-like capillary beds were identified. Some of these beds were densely and others loosely arranged. Two types of capillaries made up these beds, tortuous and straight capillaries. These beds also showed a planate surface giving the impression that they lie directly under the mesothelium.

Animals↗

PubMed1989

Early stages of ciliogenesis in the respiratory epithelium of the nasal cavity of rabbit embryos.

Previous studies have shown that ciliogenesis in the epithelial cells of various species exhibits similarities as well as differences. In an attempt to establish whether this process is identical in epithelial cells of a single species, early stages of centriole formation not previously described were encountered. Ciliogenesis was investigated in the respiratory epithelium of the nasal cavity of 18 to 23-day-old rabbit embryos. The appearance of groups of deuterosomes and fibrous granules is followed by the radial formation of procentrioles around the deuterosomes and parent centrioles. The majority of the procentrioles, forming acentriolarly, occur in pairs, with their distal ends facing each other, between the deuterosomes. Subsequent growth of these procentrioles between deuterosomes in a group results in separating the deuterosomes from one another. The deuterosomes, however, still remain interconnected by means of the growing procentrioles. Accordingly, long chains and networks consisting of the above-mentioned structures are formed. After the procentrioles have attained a certain length, the chains and networks split into separate deuterosome-procentriole complexes. During these earlier stages of ciliogenesis fibrous granules are present, however, their function is yet to be determined.

Animals↗

PubMed1979

The effect of allantoin on cellular multiplication in degenerating and regenerating nerves.

Injury to a peripheral nerve is, among other things, followed by degeneration of axons and myelin, as well as by a sharp increase in the number of cells (especially Schwann cells) in the part distal to the injury. The effect of allantoin--a cell proliferant--was tested on the above-mentioned reactions in the sciatic nerve of rats. The nerves were crushed and re-exposed 7, 14, 21, 35 and 90 days after the injury, and removed for histological examination. The results obtained in a group of rats treated with allantoin were compared with those obtained in a control group of rats. The results showed that allantoin had a statistically significant effect on the cellular multiplication seen in the nerve 7 and 14 days after the injury. Myelin degeneration was also found to be more advanced in the allantoin-treated nerve preparations examined 14 and 21 days postoperatively than in the control nerve preparations.

Allantoin↗

PubMed1979

A rapid silver impregnation method for nervous tissue: a modified protargol-peroxide technic.

A rapid, reliable silver impregnation method is described for nervous tissue fixed in formol-saline, Bouin or Susa. Sections are impregnated for 10-15 minutes at room temperature or 37 C in a solution containing 0.5 g Protargol-S, 0.005-0.01 g allantoin, 1 ml of 1% Cu[NO3]2, 1 ml of 1% AgNO3, and 1-2 drops of 30% H2O2 in 100 ml distilled water. Thereafter the sections are reduced in a hydroquinone-formalin solution. This is followed by gold toning and subsequent reduction and mounting. Alternatively, following the first reduction, the silver image can be intensified by placing sections in a silver-allantoin bath which is followed by reduction and mounting. This method is very reliable and selective, making it suitable for general routine and research use.

Allantoin↗

PubMed1977

A silver impregnation method for nervous tissue suitable for routine use with mounted sections.

A simple, reliable silver impregnation method for nervous tissue is described for tissues fixed in various fixatives including formalin, Bouin, and Susa. Sections are impregnated in a solution containing 1 g Protargol, 2 ml of a 1% Cu(NO3)2 solution, 2 ml of a 1% AgNO3 solution, and 2-4 drops 30% H2O2 in 100 ml distilled water. Sections are impregnated 2-5 days at 37 C and thereafter reduced in a hydroquinone-formalin solution. This is followed by gold toning and subsequent reduction, dehydration and mounting. This method has been found to be very reliable and selective.

Animals↗

PubMed1976

Experimental microsurgery in peripheral nerves.

A surgical technique for the reconstruction of severed peripheral nerves is described. This technique reduces the mechanical manipulation and trauma to the nerve during suturing. Histological studies revealed that scar formation at the suture site was reduced to a minimum. The suture material did not prevent the downgrowth of regenerating axons. Nerves in which suturing was either inaccurately or accurately done, were compared. Histological examination of these nerves revealed that axonal regeneration in nerves with 8 or more sutures was superior to that in nerves with only 2 sutures.

Animals↗