Biomedical subjects

J M Loots

Publications and source records attributed to J M Loots.

6 recordsLinked to original sources

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↗

PubMed1975

Ultrastructural localisation of calcium in peripheral nerves of the rat.

An ultrastructural method which is specific for calcium was applied in a study of calcium distribution in the axoplasm of myelinated nerve fibres of rat sciatic nerves. Electron-dense deposits of calcium oxalate were seen in smooth-membraned vesicles within the axoplasm, and between the two external membranes of axoplasmic mitochondria. The significance of calcium localisation at these sites is discussed, with special reference to the role of calcium in fast axoplasmic transport.

Animals↗

PubMed1975

The effect of porphyrin precursors on monosynaptic reflex activity in the isolated hemisected frog spinal cord.

The porphyrin precursors beta-aminolevulinic acid (beta-ALA) and porphobilinogen (PBG) which accumulate, and are excreted in the urine in increased amounts during acute attacks of porphyria, were tested for their effects on reflex activity in the isolated hemisected spinal cords of Xenopus laevis. The two compounds were found to exert an inhibitory effect on monosynaptic ventral root responses, as well as on dorsal root responses (DRR) and dorsal root potentials (DRP). The latent period for inhibition of the monosynaptic response was longer than that for the DRR and DRP. The sensitivity of the preparations to the effect of the porphyrin precursors was subject to some seasonal variation. BETA-ALA and PBG did not effect conduction in isolated sciatic nerves at a concentration of 1 mg/ml.

Aminolevulinic Acid↗