A turbid solution was formed through the reaction between ?-PGA and cetylpyridinium chloride(CPC) and the turibidity was measured by using ultraviolet-visible spectroscopy at 680nm.The linearity between the concentration of ?-PGA and its absorbance,the stability,repeatability and recovery of the method were studied.Through the reaction of ?-PGA with CPC,a homogeneous turbid solution was formed.The turbid solution was stable in 3h under proper pH value and ion strength,the absorbance of the solution at 680nm had a good linear relationshi Pwith the concentration of ?-PGA in the range 12.5~50?g/ml(R2=0.9939).The recovery was within the range of 86%~99.75%(n=5).The relative standard division of the method for determining ?-PGA at the concentrations of 5,10 and 40?g/ml were 0.14%,0.23%和0.025% repeatability.The turbidmetric method has advantages of convenience,simplicity and good repeatability and can be used to control the quality of ?-PGA and its products.

BACKGROUNDMeningioma is one of the most common primary tumors of the central nervous system, but there are not many detailed studies on the sex, age, subtypes and locations of large series. This study was a retrospective analysis of the characteristics of meningioma cases consecutively operated on at a single institution in China from 2001 to 2010.

METHODSThis study investigated the demographic background of 7084 meningioma cases, and the subtypes and locations of the tumors. Sex and age distributions were analyzed, and the pathological subtypes were classified according to the World Health Organization (WHO) classification. The location of the meningiomas was also categorized.

RESULTSThe female:male ratio of the 7084 cases was 2.34:1. The mean age was 51.4 years (range, 11 months-86 years). The mean age of cases of WHO grade I meningioma was significantly older than that of grade II or III meningiomas (P < 0.001, Fisher's Least Significant Digit test). There was a significantly higher female:male ratio in WHO grade I meningiomas than in grade II or grade III meningiomas (2.57, 1.03 and 0.76, respectively; P < 0.001, χ(2) test). Meningothelial (n = 2061) and fibrous meningiomas (n = 3556) were the most common subtypes, comprising 79.3% of all meningiomas. All meningioma cases were classified into 23 locations in this study, with the cerebral convexity the most common site (38.33%, n = 2722). Cases with uncommon locations such as extra-cranial and sylvian fissure meningiomas were also present in this series.

CONCLUSIONSFemale predominance was found for benign meningiomas, while malignant subtypes showed male predominance. The mean age of patients with WHO grade I meningiomas was older than that of patients with higher-grade tumors. Meningothelial and fibrous meningiomas were the most common subtypes. The cerebral convexity was the most common meningioma location.

Adolescent ; Adult ; Age Distribution ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Male ; Meningioma ; epidemiology ; Middle Aged ; Sex Distribution ; Young Adult

Adolescent ; Adult ; Aged ; Female ; Humans ; Male ; Meningioma ; diagnosis ; Middle Aged ; Retrospective Studies ; Young Adult