Effect of low power laser irradiation on nociceptive cells in Hirudo medicinalis

The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the nociceptors in Hirudo medicinalis was studied. The results show that low power laser irradiation does not: affect the membrane potential or the excitability of the nociceptive neurons, affect the mechanical pressure required to activate the nociceptors or their action potentials. The results indicate that the analgesic effects reported in humans with "laser-acupuncture" with similar modes of low power laser are likely not explained by effects on nervous tissue.

Low power laser irradiation does not affect the generation of signals in a sensory receptor

The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

[Flow cytometer (FCM) in biological characteristics of nasopharyngeal carcinoma xenografts in nude mice]

Tumor tissue from a patient with nasopharyngeal carcinoma was transplanted to nude mice (BALB/c) and had successfully been maintained through ten passages. The nude mice tumor and the primary human tumor were assayed by FCM for the DNA content in addition to conventional pathological examination, chromosome analysis and EBV assay. The tumor incidence in the different passages showed a marked change ranging from 25% to 81% with a mean value of 52% which tended to increase, however. The doubling time of six tumors in the ninth passage showed no great change 6-12 weeks after transplantation with a mean about 4.3 days. But at week 12, there was a significant difference between each tumor volume, ranging from 438 to 1,998 mm3. By FCM, it was found that the DNA index remained constant in both the primary and nude mice tumors. Among the nude mice tumors in different passages, the distribution of various phase cells in cell cycle was similar to that of the primary tumor. In conclusion, the use of FCM to assay the cellular DNA content in nude mice tumor is rapid and sensitive. It is helpful, for the nude mice tumor, in identifying stability of the biological characteristics and in studying of the mechanism of chemotherapy and radiotherapy in the future.

The effects of lead ion on immune function of rabbit alveolar macrophages: quantitation of immune phagocytosis and rosette formation by 51Cr in vitro

Experiments by a 51Cr-labeling technique were performed to investigate the effects of lead (Pb2+) on immune phagocytosis and Fc-rosette formation of rabbit pulmonary alveolar macrophages (PAMs). Evidence is presented that Pb2+ at concentrations of 10(-3) and 10(-4)M could inhibit these functions of PAMs. The degree of inhibition corresponded to the concentration of this heavy metal ion in vitro.