THE INFLUENCE OF MAGNETIC FIELDS ON THE PRIMARY HEALING OF INCISIONAL WOUNDS IN RATS

Our studies were conducted to examine the influence of extremely low frequency magnetic fields (ELF-MF) on skin wound healing in male adults rats. We used 40 Hz and 10 mT sinusoidal fields. We evaluated the rate of wound healing by determining the tissue hydroxyproline concentration and scar imaging in electron microscope. The systemic body response to ELF-MF was detected by analysis of blood morphological and biochemical parameters, such as: RBC, WBC, hemoglobin, hematocrit, reticulocytes, electrolytes, urea, and total protein concentration.

ELF-MF induced the increase of hydroxyproline level in scar tissue and intensified the maternity of collagen seen in the electron microscope. The increase of reticulocyte number in blood confirmed that the healing process in experimental animals was supported by the activation of the oxygen supply and utilization processes, as a result of erythropoietic intensification, without simultaneously upsetting cellular energetic processes. We did not obtain changes in biochemical parameters in blood, such as: electrolytes, urea, and total protein concentration, so we concluded that ELF-MF evoked no negative systemic response.     

OBSERVATIONS ON THE EFFECT OF GROWTH-STIMULATING COMPOUNDS ON THE HEALING OF WOUNDS ON APPLE TREES

Wounds were made at various times of the year on the trunks and large branches of apple trees with a 1 in. bit and treated with a number of organic compounds in lanoline paste. The healing of these wounds was followed through two growing seasons by tracing and measuring the area of exposed wood at different times after wounding.
Callus growth was practically confined to the summer months. Development of callus was improved by applications of lanoline, and the lanoline effect could be further enhanced in the early part of the first growing season following treatment by the addition of certain growth-stimulating compounds including 4-chloro-3:5-dimethylphenoxyacetic acid and 2:4-dichlorophenoxyacetic acid. Indolyl-3-butyric acid probably also caused some stimulation. After the period of initial stimulation the rate of callusing was approximately the same on treated as on untreated wounds.     

THE INFLUENCE OF INFECTION WITH NOSEMA APIS ON THE ACTIVITIES AND LONGEVITY OF THE WORKER HONEYBEE

Infection of the adult worker honeybee with Nosema apis reduces or obviates brood feeding and causes her to commence foraging earlier than a healthy bee. The length of foraging activity and the total length of life of infected bees is reduced.
In colonies infected with N. apis the rate of brood rearing is severely depressed during April, May and June, the degree of depression being proportional to the percentage infection.
Infection decreases during July, August and September, and consequently the rate of brood rearing increases, but the resulting addition in foraging population is usually too late to increase the honey crop.     

EFFECT OF THE HYDROGEN ION CONCENTRATION ON THE PHAGOCYTOSIS AND ADHESIVENESS OF LEUCOCYTES

1. Immediately after coming into contact with glass, leucocytes are most adhesive at pH 8.0 or > 8.0. 2. Agglutination of leucocytes increases with increasing H ion concentration from pH 8.0 to 6.0. 3. In phagocytosis experiments where leucocytes creep about on the slide picking up articles the optimum pH is 7.0. Here ameboid movement is probably the limiting factor. 4. The optimum for phagocytosis of quartz from suspension is on the acid side of neutrality at or near pH 6.7. 5. Phagocytosis of quartz increases with the acidity, while adhesiveness of leucocytes to glass increases with the alkalinity.     

THE DEFORMABILITY AND THE WETTING PROPERTIES OF LEUCOCYTES AND ERYTHROCYTES

The resistance to deformation of polymorphonuclear neutrophile leucocytes under the conditions of our observations has been shown to be on the average considerably less than the resistance to deformation of large mononuclear leucocytes. It is recognized of course that the viscosity of leucocytes, as of other cells, may be markedly influenced by osmotic conditions (17), by the reaction of the suspending medium (18, 19), by temperature, or by injury (20, 21). Although the conditions of our observations were quite different from those of the body, they were nevertheless closely similar to those of simultaneous phagocytosis experiments in which the cells functioned exceedingly well (3). Moreover E. R. and E. L. Clark (22) have noted that polymorphonuclear leucocytes in the tails of living tadpoles were more fluid than the macrophages. And Goss (23) in microdissecting human polymorphonuclear neutrophiles reports that they are more fluid than the clasmatocytes and monocytes studied by Chambers and Borquist (24). Other types of leucocytes have in our experience seemed to fall between the large mononuclear and the polymorphonuclear leucocytes in their average resistance to the interfacial tensions. The leucocyte of each type studied is surrounded by an exceedingly delicate membrane. This membrane appears under the dark-field microscope as a pale, silvery line not distinguishable by inspection alone from a simple phase boundary between two immiscible liquids. That this is a membrane, however, and not a mere interface between immiscible phases, seems certain. In the first place the cell cytoplasm and the suspending medium are not immiscible. When the cell organization is broken down by the interfacial tension the greater part of the cell contents is immediately dissolved or dispersed. Goss (23) has noted that when the membrane is torn with a microdissection needle disintegration at once spreads over the membrane and the cytoplasm undergoes profound change. Moreover it is improbable that a simple phase boundary could exist in the presence of so much protein, lipoid, and other surface active materials as are present in protoplasm; the tendency of these substances to lower the free interfacial energy must necessarily tend to their adsorption in the interface until, if sufficient material is available at the interface, an adsorption film or membrane may be formed. Kite (25), in a pioneer microdissection study, described the polymorphonuclear leucocyte as "naked" protoplasm. The contradiction between this statement and those just made is more apparent than real. For the capacity swiftly to form a limiting membrane between itself and other liquids is an attribute of "naked" protoplasm, as has been shown by the beautiful experiments of Chambers (20). The present study of the wetting properties of leucocytes shows that their external membranes are hydrophilic, a character suggesting a surface in which proteins, probably bound water and salts (27), possibly the polar radicles of soaps or fatty acids, rather than non-polar lipoid groupings, are predominantly exposed. This makes it the more remarkable that a cell of such fluidity as for instance the polymorphonuclear leucocyte, composed largely of water and of water-soluble materials, should maintain its integrity in an aqueous medium with the aid of a membrane so delicate and so mobile. The mobility of the membrane, frequently extended in forming new pseudopodia or spreading over the surface of particles being ingested, must require constant entrance into and exit from the membrane of component materials, and their constant reorganization there. The limiting factors in the reformation of such a membrane would be the amounts of adsorbable materials available and their rates of movement up to the surface rather than the time required for orientation there, since the latter phenomenon is exceedingly rapid. Harkins (29), for instance has calculated that at a water-water vapor interface at 20°C., from the area occupied by one molecule of water, a molecule would jump out into the vapor and a vapor molecule would fall into this area of the surface 7,000,000 times in one second; the time of orientation of the water molecule he estimates to be of the order of 1/100,000,000 second or less. The mammalian erythrocyte possesses a surface membrane capable of being folded and of withstanding tension in the interface. This has also been stretched by microdissection needles (21). The surface of the erythrocyte, as evidenced by its wetting properties, is relatively hydrophobic, relatively non-polar in character, as compared with the leucocyte. Evidence indicating that the erythrocyte surface contains both lipoid and protein components has been summarized in earlier papers (8, 30). We have little to add here other than to point out that the wetting properties of the chicken erythrocyte surface are similar to those fully described for the mammal. A serious source of error in certain isoelectric point determinations is discussed.     

大鼠尾核头部对中缝大核神经元单位活动的影响及其可能途径

用玻璃微电极细胞外记录大鼠中缝大核(NRM)神经元的单位放电。共记录277个细胞,NRM 神经元自发放电频率大都在每秒0.5—20次之间,平均为6.41 Hz。其中221个神经元被电刺激尾所激活,35个被抑制,21个无明显变化。NRM 神经元对躯体刺激的反应类型与自发放电的特征有关,兴奋型神经元的自发放电频率较低((?)=4.96Hz),而抑制性神经元的自发放电频率较高((?)=15.03 Hz)。在24例兴奋型神经元中,刺激尾核头部能够激活大多数 NRM 神经元的自发放电和抑制其伤害感受性反应。导水管周围灰质微量注射纳洛酮(2.5ug/0.5μl,n=15)。能够明显阻断刺激尾核头部激活 NRM 神经元自发放电和抑制伤害感受性反应的效应。