Effect of successive irrigation of subarachnoid cavity on body temperature and cerebrospinal fluid-related index in suppurative meningitis model dogs

BACKGROUND： At present, suppurative meningitis is mainly treated through anti-infection with antibiotics, depressing encephalic pressure with mannitol , lowering body temperature with drugs , supporting treatment, etc. However, Jt takes a long course of treatment and has poor therapeutic effect. Successive irrigation of subarachnoid cavity maybe have better effect on suppurative meningitis.OBJECTIVE： We compared the successive irrigation of subbarachnoid cavity with routine therapeutic methods to observe the effect of successive irrigation of subarachnoid cavity on the body temperature, cerebrospinal fluid pressure, the number of white blood cell and the level of protein of suppurative meningitis dogs. DESIGN： A randomized and controlled animal experiment SETTING： Institute of Neuroscience, Taihe Hospital Affiliated to Yunyang Medical College MATERIALS： Totally 17 healthy adult male Beagle dogs, of common grade, weighing 9 to 10 kg, were involved in the experiment, and raised in the 20 ℃ temperature with relative humidity of 50% for 1 week. They were randomized into 3 groups： normal group （n=5）, control group （n=5） and irrigation group （n=6）. Artificial cerebrospinal fluid was prepared according to the level of glucose and chloride of cerebrospinal fluid of normal dogs, and then it was sterilized with high pressure. METHODS ： This experiment was carried out in the experimental animal center of Yunyang Medical College from April to August 2001. ① After the dogs were anesthetized,1 mL fresh staphylococcus aureus liquid [（1.5-1.6）× 10^9 L 1] was injected into medullary cistern to establish suppurative meningitis models. ② After models were successfully established, intravenous drip infusion of 1.2 ×10^6 U/（kg.d）, muscular injection of sulfadiazine sodium of 100 mg/（kg.d ）and intravenous injection of 200 g/L mannitol of 5 g/（kg .time） for 3 times a day were performed in the control group. The irrigation of subarachnoid meningitis was conducted in the irrigation group besides the routine treatments in the control group： Artificial cerebrospinal fluid was successively injected into the epidural catheter in the waist part. The mixtures of artificial cerebrospinal fluid and inflammatory cerebrospinal fluid flowed out incessantly from epidural catheter of medullary cistern. Irrigation was ended 48 hours later. Dogs were routinely raised in the control group. ③ From the first day after being modeled to the 14^th day after treatment, the rectal temperatures were daily measured in the morning, at noon and in the evening respectively, then the mean temperatures were calculated. From the 2^nd day after being modeled to the 14^th day after treatment, puncture at waist was given once, and the cerebrospinal fluid pressure, the number of white blood cells and the level of protein were measured. MAIN OUTCOME MEASURES ： The body temperature, cerebrospinal fluid pressure, the number of white blood cells and the level of protein were measured on suppurative meningitis model dogs. RESULTS＂ Totally 17 Beagle dogs were involved in this study.①The body temperatures of dogs were significantly reduced in the control group and in irrigation group on the 1^st day after treatment and lower than suppurative meningitis model dogs on the 2^nd day after being modeled （P 〈 0.05）. The body temperatures were gradually decreased in control group from the 2^nd day after being modeled to the 14^th day after treatment （P 〈 0.01）, but were significantly higher than those of dogs in normal group on the 14^th day after treatment （P 〈 0.05）. The body temperatures of dogs were gradually decreased in irrigation group on the 2^nd day or 3^rd day after treatment （P 〈 0.01） and then were close to the normal body temperature on the 14^th day after treatment. ②There was the same cerebrospinal fluid pressure in control group as in irrigation group on the 2^nd day after being modeled （P 〉 0.05）, but significantly decreased in two groups from the 1s＇ day or 2^nd day after treatment （P 〈 0.01）, and cerebrospinal fluid pressure was close to the normal level in irrigation group. Although the cerebrospinal fluid pressure raised a little on the 3^rd day or 4^th day after treatment in the irrigation group （P〈 0.05）, but recovered to the normal level on the 9^th day after treatment again. It decreased slowly in the control group and still was sig- nificantly higher than normal group on the 14^hd day after treatment （P〈 0.01 ）. ③No significant difference existed in number of white blood cell and the level of protein between control group and irrigation group on the 2^nd day following modeled. Both of them began to significantly decrease on the 1^st and 2^nd day after treatment （P 〈 0.01 ）. Although the number of white blood cell and the level of protein rebounded a little in irrigation group 3 or 4 days after treatment （P〈 0.05）, they were gradually decreased and recovered to normal levels on the 13^th day after treatment. The number of white blood cell and the level of protein slowly decreased in the control group compared with irrigation group and were still significantly higher than normal group on the 14^th day （P〈 0.01 ）. EONELUSEON ： Irrigation of subarachnoid cavity can decrease the body temperature, cerebrospinal fluid pressure, the number of white blood cells and the level of protein at early stage of suppurative meningitis, and the therapeutic effect is better than that of routine treatment.

Variation of Lasing Wavelength of Fiber Grating Semiconductor Laser with Temperature for Different External Cavity Lengths

For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical results are in agreement with reported experimental observations.