[Related factors of revision of distal femoral fractures treated with lateral locking plate].

OBJECTIVE: To analyze the factors related to the need for revision surgery due to nonunion or internal fixation failure after the treatment of distal femoral fracture with lateral locking plate (LLP). METHODS: Retrospective analysis was made of the clinical data of 130 cases with distal femoral fracture treated in our hospital from March 2005 to March 2019. SPSS 17.0 software (univariate analysis and Logistic regression analysis) was used to analyze the general condition [gender, age, body mass index (BMI), comorbidities, smoking history], injury related factors (energy of injury, open or closed injury, AO/OTA classification of fracture, fracture area distribution), operation related factors (operation time, reduction quality, postoperative infection) and construct characteristics of internal fixation. RESULTS: Twelve of 130 patients who were included in the study underwent revisional surgery, with a revision rate 9.2%. Univariate analysis showed that there were significant differences in age, BMI, AO/OTA classification, fracture area distribution, operation time, reduction quality, length of plate/fracture area, length of plate/fracture area above condylar between the two groups (P < 0.05). Logistic regression analysis showed that AO/OTA classification (A3), supracondylar involved fracture, operation time, reduction quality and the length of the plate/fracture area above the condylar were the possible related factors (P < 0.05). Destruction of the medial support ability of the femur in comminuted type A3 fracture, supra-condylar cortex area fracture involvement, increase of the bending stress of the LLP due to poor fracture reduction quality, damage of the blood supply of fracture end due to long-time operation, and stress concentration caused by insufficient length of plate might be risk factors of revisional operation after the treatment of distal femoral fracture with LLP. For the patients who needed revision after LLP treatment, additional use of medial minimally invasive plate fixation and autologous bone transplantation, change to intramedullary nail fixation were commonly used clinical treatment strategies. CONCLUSION: AO/OTA classification (A3), supracondylar involved fracture, long operation time, poor reduction quality and the length of the plate/fracture area above the condylar were the possible predictive factors of the revision in distal femoral fractures treated with lateral locking plate. The appropriate application of the locking plate and operation strategy are the key to reduce the revision rate in distal femoral fractures.

[Analysis of risk factors for necrosis of femoral head after internal fixation surgery in young and mid-aged patients with femoral neck fracture].

OBJECTIVE: To retrospectively analyze the risk factors of avascular necrosis of femoral head (ANFH) after internal fixation in young and mid-aged adults. METHODS: From January 2007 to December 2017, femoral neck fracture patients (18-60 years old) treated by reduction and internal fixation were retrospectively studied in Peking University Third Hospital. We recorded their gender, age, body mass index (BMI), American Society of Anesthesiology (ASA) grade, reason of injury, fracture side, interval between injury and surgery, location of fracture line, Garden classification, Pauwels classification, reduction method (open or closed), internal fixation and reduction quality. The diagnosis of ANFH was confirmed based on X-ray and MRI images during the follow-up. The internal fixation method included cannulated compression screw (CCS) or dynamic hip screw (DHS, with or without anti-rotation screw). χ2 test and Logistic regression analysis were used to analyze the relationship between the various factors and postoperative ANFH. RESULTS: A total of 113 patients were included in this study, including 63 males and 50 females with an average age of (43.17 ± 12.34) years. They were followed up by (25.08 ± 16.17) months. ASA grade included grade I (21 cases), grade II (55 cases) and grade III (37 cases). The reasons of injury included low-energy trauma (76 cases) and high-energy (37 cases). The fracture line included subcapital type (37 cases), transverse type (74 cases) and basal type (2 cases). Garden classification included type I (3 cases), type II (46 cases), type III (39 cases) and type IV (25 cases). Pauwels classification included type I (21 cases), type II (55 cases) and type III (37 cases). Interval between injury and surgery was (3.88 ± 3.66) days, 108 patients and 5 patients performed closed and open reduction respectively. 63 patients performed CCS, and 50 patients performed DHS. The reduction quality included grade A (91 cases), grade B (18 cases) and grade C (4 cases). 18 patients developed ANFH after surgery, the incidence rate was 15.93% (18/113). The result of χ2 test showed the reason of injury (OR=0.19, P < 0.01), Garden classification (OR=0.13, P < 0.01), Pauwels classification (OR=0.12, P = 0.02), internal fixation method (OR=3.29, P = 0.04) and reduction quality (OR=0.33, P < 0.01) were significantly associated with ANFH. These five factors were further included into the Logistic regression analysis, and its results showed that the reason of injury (OR=4.11, P = 0.03) and Garden classification (OR=4.85, P = 0.04) were statistically significant. CONCLUSION: The reason of injury, Garden classification, Pauwels classification, internal fixation and reduction quality may increase the risk of ANFH after surgery, and the reason of injury and Garden classification were much more significant.

[Application of the modified internal fixation method of minimally invasive percutaneous plate osteosynthesis in treatment of proximal humeral fracture].

OBJECTIVE: To study the clinical outcomes and characteristics of fracture healing of a modified internal fixation method, which was implemented by placing four and two screws respectively at the proximal and distal end of the locking plate in the minimally invasive percutaneous plate osteosynthesis (MIPPO) for patients with proximal humeral fractures. METHODS: Patients in Peking University Third Hospital from February 2010 to December 2016 were brought into this retrospective study. Based on different operation methods, they were divided into minimally invasive (MI) group and non-minimally invasive (non-MI) group, and the patients in MI group were performed with the modified internal fixation. In order to observe the varying efficacy for different fracture types between the two groups, we further investigated the patients with Neer two-part and three-part fracture, respectively. The follow-up parameters included general physical examination, X-ray, visual analogue scale (VAS) and Constant-Murley score. RESULTS: A total of 117 patients with an average age of (61.5±16.2) years met the inclusion criteria, and MI group included 45 patients, non-MI group included 72 patients. According to the Neer classification, there were 46 cases of two-part fracture, 63 cases of three-part fracture and 8 cases of four-part fracture. In MI group, there were 17 males and 28 males with an average age of (62.2±17.1) years, including 18 cases of two-part fracture, 23 cases of three-part fracture and 4 cases of four-part fracture. In non-MI group, there were 27 males and 45 females with an average age of (60.1±17.7) years, including 28 cases of two-part fracture, 40 cases of three-part fracture and 4 cases of four-part fracture. There were no significant differences between the two groups in terms of gender (P=0.975), age (P=0.545) and fracture type (P=0.756). The average hospital-stay in MI group and non-MI group was (2.8±1.1) days and (4.3±1.3) days (P=0.023), the operation time was (67.8±14.9) min and (102.3±34.1) min (P<0.001), the blood loss was (21.3±6.5) mL and (181.5±55.6) mL (P<0.001), the Constant-Murley score was 6.1±0.9 and 6.5±0.8 (P=0.032) one week after surgery, and the Constant-Murley score was 66.1±4.3 and 63.4±4.9 (P=0.006) three months after surgery, MI group had significant advantages in these aspects. In terms of Neer two-part and three-part fracture, the VAS score (5.9±0.8) one week postoperatively and the Constant-Murley score (66.6±3.7) three months postoperatively were significantly superior in MI group (P<0.05). In MI group, delayed fracture healing occurred in 1 case (2.2%) and abduction was restricted in 1 case (2.2%). In non-MI group, delayed fracture healing occurred in 3 cases (4.2%) and abduction was restricted in 2 cases (2.8%). There were no internal fixation complications and humeral head necrosis in both groups. CONCLUSION: Applying the modified internal fixation in MIPPO to cure proximal humeral fractures is effective clinically with thick callus formation occurring at the fracture site. The fracture can achieve normal healing and the shoulder functions can restore well, indicating the modified surgical method is a good treatment option.

Initial empiric antibiotic therapy for community-acquired pneumonia in Chinese hospitals.

OBJECTIVES: Studies on treatment of community-acquired pneumonia (CAP) in China are scarce. We performed a study to investigate empiric antibiotic practices for patients hospitalized with CAP in China and the risk factors for treatment failure. METHODS: Data were collected from a national Chinese hospitalization database. Adult patients who were diagnosed with CAP between 1 October 2014 and 30 September 2015 were identified. We studied initial empiric antibiotic regimens, microbiologic sampling, treatment failure, in-hospital mortality and length of hospital stay. RESULTS: We included 18 043 adult patients from 185 hospitals who met all the study inclusion criteria. The most common initial antibiotic regimen for CAP was monotherapy with a fluoroquinolone (14.8%, 2671/18 043). The most common initial antibiotic (used alone or in combination with other antibiotics) was levofloxacin (15.7%, 4597/29 278 (this denominator represents the total number of initial antibiotics)). The microbiologic sampling rate was 26.9% (4851/18 043). A total of 4050 (22.4%) of 18 043 patients experienced treatment failure. Multivariate logistic regression demonstrated that older age, male sex, coexisting lung cancer and use of regimens not covering atypical pathogens were risk factors for treatment failure. In-hospital mortality was 2.1% (380/18 043). The median hospital length of stay was 11 days (interquartile range, 8-15 days). CONCLUSIONS: Patients receiving Chinese guideline-adherent regimens had better outcomes, and atypical pathogen active regimens were associated with a lower treatment failure rate and shorter length of hospital stay.

[Diagnosis and treatment for the basicervical fractures of the trochanteric region].

OBJECTIVE: To evaluate the rate of basicervical fractures and document their diagnosis and treatment. METHODS: From January 2005 to May 2016, 28 basicervical fractures of the 832 trochanteric fractures were collected and evaluated. The patients were treated with multiple screws, dynamic hip screw (DHS), intramedullary nail. Via the operation time, postoperative hospitalization, loss of blood duration the operation, hidden blood loss, total blood loss, mean union time and the final follow-up Harris hip score, the characteristics of different internal fixations were compared and analyzed. RESULTS: The incidence of basicervical fractures was 3.37% (28/832) in our study. In the intramedullary nail group (16 patients), the operation time was 55 (20,120) min, the postoperative hospitalization was 3(2, 7) d, the intraoperative blood loss was 50 (5,100) mL, the hidden blood loss was 533.37 (376.19, 987.15) mL, and the total blood loss 627.35 (406.19, 1037.16) mL. The union time and final follow-up Harris score were 6 (3, 9) months and 90.25 (74,100) min. In the DHS group (8 patients), the operation time was 87.5 (65,115) min, the postoperative hospitalization was 5.5 (2, 17) d, the intraoperative blood loss was 100 (50,300) mL, the hidden blood loss was 278.11 (202.43, 849.97) mL, and the total blood loss 580.19 (368.55, 899.97) mL . The union time and final follow-up Harris score were 5.5 (4, 12) months and 85.5 (84, 87) min. In the multiple screws group (4 patients), the operation time was 47.5 (35, 75) min, the postoperative hospitalization was 5 (2, 12) d, the intraoperative blood loss was 20 (2, 70) mL, the hidden blood loss was 150 (100.00, 412.01) mL, and the total blood loss 195.00 (120.00, 414.01) mL. The union time and final follow-up Harris score were 4 (4, 6) months and 80 (61, 97) min. The patients treated with multiple screws and intramedullary nail had a shorter operation time than the DNS group, but no obvious difference was found between the other two groups (P=0.367). Postoperative hospitalization had no significant difference among the three groups. The intraoperative bleeding was more in the DHS group, the other two groups had no significant difference (P=0.100). However, the hidden blood loss was more in the intramedullary nail group, the other two groups had no significant difference (P=0.134). The total blood loss in the intramedullary nail group was more than multiple screw group, similar to the DHS group (P=0.483). One patient treated with multiple screws underwent internal fixation failure three months after operation. The mean union time and final follow-up Harris scores had no significant difference among the three groups (P>0.05). CONCLUSION: Through this study, we found that the incidence of basicervical fractures is low. Fractures with no shift can be confirmed by preoperative X-ray. For displaced fractures, preoperative CT+3D reconstruction is recommended. Surgical treatment by closed reduction and internal fixation with DHS or intramedullary nail is shown to be very effective.

[One of the pitfalls in the surgical treatment of maisonneuve fractures: a case report].

There exist controversies in the surgical treatment of maisonneuve injury with regard to reduction and fixation of syndesmosis and management of proximal fibular fracture. It is very important for the orthopaedic surgeons to learn more techniques and avoid pitfalls from clinical practice. We summarized the clinical data of 1 failed case, a 20-year-old girl with big body weight who underwent a primary surgery for the treatment of maisonneuve fracture with minimally invasive reduction and fixation of ankle syndesmosis and posterior malleolus and open reduction and internal fixation of medial malleolus, then a revision surgery for the treatment of iatrogenic syndesmotic malreduction with open reduction and re-stabilization of ankle syndesmosis supplemented with open reduction and internal fixation of proximal fibular facture. The malreduction of distal fibula was not found until finishing the postoperative computed tomography (CT) scan 2 weeks after the primary surgery, then the patient experienced an revision surgery including removal of the screws installed primarily for fixation of ankle syndesmosis, and open reduction and internal fixation of proximal fibular fracture, and limited open reduction and re-stabilization of ankle syndesmosis. Then the patient rehabilitated regularly under the direction of the surgeon who performed these two operations, and the postoperative recovery was smooth, then the hardwares for fixation of ankle syndesmosis and fracture of proximal fibula and medial malleolus were removed at different postoperative time. The patient experienced an excellent outcome at the end of the 3-year follow-up. The reasons for the failure in this case might include the overemphasized minimally invasive technique in the process of reduction, inaccurate assessment of intraoperative fluoroscopy and postoperative radiographs, and inappropriate utilization of the reduction clamp. Attention should be paid to the fact that an obliquely placed clamp for closed reduction of diastasis of ankle syndesmosis could result in syndesmotic malreduction. The worsened alignment of the fracture end of proximal fibula observed by intraoperative fluoroscopy may alert surgeons to syndesmotic malreduction. Partial exposure of syndesmosis and anatomical reduction and fixation of proximal fibular fracture may be useful measurres to avoid malreduction of ankle syndesmosis in the surgical treatment of maisonneuve injury in some patient, especially the patient with critically destabilized ankle.

[Surgical treatment of inferior pole comminuted fractures of patella with new type tension band].

OBJECTIVE: To study the effectiveness of inferior pole fracture of patella treating by the new tension band. METHODS: From Dec. 2011 to Dec. 2013, 21 patients with inferior pole fracture of patella were treated with the new tension band which consisted of cannulated screw, titanium cable and shims. There were 21 patients[10 males, 11 females, the average age was 54 years(21 to 79)],of whom,all were "fell on knees". RESULTS: The average operation time was 89 min (57-197 min),the follow-up visits were done from 7-31 months (average 18 months), the bone healing time was from 8-12 weeks (average 10.5 weeks). The post operation assessment was done by Bostman score, from 20-30 (average 27),10 excellent,and 11 good. No complication occurred. CONCLUSION: The new tension band is the effective treatment for inferior pole fracture of patella. The internal fixation is reliable, it is simple to operate, and patients can take exercises as early as possible. Therefore, the new tension band has a better clinical value.

Intra-arterial chemotherapy is reliable in preventing high-risk superficial bladder cancer from recurrence and progression.

The purpose of this prospective study was to evaluate the therapeutic effects of intra-arterial chemotherapy in preventing high-risk superficial bladder cancer from recurrence and progression. from may 2003 to December 2007, 52 patients were divided randomly into 2 groups. Twenty-five patients were given intra-arterial chemotherapy with gemcitabine and cisplatin, and 27 patients received intravesical instillation with epirubicin. After 6-67 months of follow-up (median, 40 months), the overall recurrence-free rates of the intra-arterial chemotherapy and intravesical instillation groups were 83.3% and 33.4%, respectively (p=0.001 log rank). Tumor progression was not found in the intra-arterial chemotherapy group while 7 patients in the intravesical instillation group had tumor progression. The overall tumor progression-free rates were 100% and 58.5%, respectively (p=0.009 log rank). The patients with functional bladders were 100% and 81.5% in the intra-arterial chemotherapy and intravesical instillation groups after 67 months of follow-up, respectively. In conclusion, intra-arterial chemotherapy is more effective than intravesical instillation in preventing high-risk superficial bladder cancer from recurrence and progression.

Two new mutations in the keratin 4 gene causing oral white sponge nevus in Chinese family.

OBJECTIVE: We investigated white sponge nevus (WSN) in a Chinese family, and tried to find new mutation and demonstrated that this mutation is the causative mutation for WSN in this family and this condition affects a functionally important segment of the keratin 4 protein. MATERIALS AND METHODS: We studied the affected family with the 32-year-old female patient, her mother, her younger sister and her daughter. Pathologic examinations were performed. DNA was extracted from peripheral blood lymphocytes, K4 and K13 genes were amplified by polymerase chain reaction (PCR) and sequenced. RESULTS: Direct sequencing of PCR products revealed two new mutations in the keratin 4 gene, the heterozygous missense mutation 1829G-->A in exon 2B, and 2324A-->G in non-coding region. No any mutation was found in the keratin 13 gene. CONCLUSIONS: We found two new mutations in the keratin 4, which may be related with the development of WSN.

A quantitative (stereological) study of the effects of experimental unilateral cryptorchidism and subsequent orchiopexy on spermatogenesis in adult rabbit testis.

The aim of this study was to examine the controversial effects of experimental unilateral cryptorchidism and subsequent orchiopexy on the number of germ cells and other morphometric characteristics of testicular and epididymal structures in adult rabbits. Unilateral cryptorchidism was induced in 11 mature male New Zealand white rabbits by returning one testis, together with the ipsilateral epididymis, to the abdominal cavity via a surgical procedure. After 3 months, testes and epididymides were removed from six animals (and from six age-matched control animals that did not undergo the surgery). Orchiopexy was performed on the five remaining animals and the testes and epididymides of these animals (and an additional six age-matched control animals) were removed 7 weeks later. A contemporary, unbiased and efficient stereological tool, the optical disector, was used to estimate the number of nuclei in the testis and epididymis using methacrylate-embedded sections of 25 micron in thickness. Cryptorchidism resulted in severe testicular atrophy and spermatogenic arrest: type A spermatogonia and Sertoli cells only were seen in the seminiferous epithelium, and the number of type A spermatogonia per testis was reduced by 84%. After orchiopexy, the testis remained atrophied and the number of type A spermatogonia returned to the near-normal range in four of five animals, but spermatogenesis was recovered only partially at the stage of early primary spermatocytes (one animal), late primary spermatocytes (two animals) or spermatids (one animal). In conclusion, cryptorchidism caused severe spermatogenic arrest that was potentially recoverable (in view of the restoration of the number of type A spermatogonia), but orchiopexy failed to induce full recovery of spermatogenesis.

Quantitative (stereological) study of the effects of vasectomy on spermatogenesis in rhesus monkeys (Macaca mulatta).

Vasectomy reversal by vasovasostomy after long-term vasectomy in men results in lower sperm counts and pregnancy rates compared with controls, and severe damage to spermatogenesis has been observed in some animal models such as mice. The primary aim of this study was to evaluate, using sophisticated stereological methods, whether vasectomy of 6 and 12 months in a non-human primate would lead to, among other morphometric changes, reduced numbers of germ cells in testes and spermatozoa in epididymides. Five normal adult male rhesus monkeys (Macaca mulatta) underwent bilateral vasectomy, with another three aged-matched normal monkeys not undergoing vasectomy. One testis together with the ipsilateral epididymis was removed from each animal at 6 months, and the other testis and epididymis, the prostate gland and seminal vesicles were removed at 12 months. Various morphometric data were obtained using stereological methods and an unbiased and efficient stereological tool, the optical disector, was used to estimate nuclear numbers of all types of spermatogenic cells in testes and spermatozoa in epididymides using methacrylate-embedded sections 25 microm in thickness. As shown by a two-way repeated measures analysis of variance, vasectomy or hemicastration (removal of the organs at 6 months) had no significant effects on all quantitative parameters of stereology obtained from the testis, epididymis, prostate gland and seminal vesicle, except that (i) sperm granuloma was observed from three of five vasectomized animals both at 6 and 12 months, and (ii) hemicastration significantly reduced the diameter of the seminiferous tubules and increased the number of type A spermatogonia per testis. In conclusion, vasectomy in the non-human primate is a safe procedure in terms of effects on the structures of the reproductive organs.

[An EGFR antisense oligodeoxynucleotides and its phosphorothioate analogue inhibit the growth of human hepatocarcinoma BEL-7404 cells].

We have previously reported that the malignant phenotype of human liver carcinoma cell line BEL-7404 was reversed by antisense EGFR RNA. The aim of this paper is to explore the effects of an oligomer targeted to mRNA for EGFR and growth of BEL-7404 cells. A 21-mer oligodeoxynucleotides (ODNs) complementary to the 5' initiation region of mRNA for EGFR was synthesized and added to medium. The results showed that the growth of BEL-7404 cells was inhibited by ODNs at concentration of 3.2 mumol/L. Inhibition of DNA synthesis of BEL-7404 cells was dose-dependent and reached to 62.1% at 3.2 mumol/L as measured by 3H-thymidine incorporation test. The inhibition of EGFR gene transcription of the cells was up to 10.5% and 14.3% respectively after incubation with ODNs by 5 and 24 hours as measured by densitometric scanning of dot (RNA) blots of EGFR. The EGFR protein (P 170) expression was also found to be blocked by 4 days' antisense oligomer treatment up to 37.4% as measured by densitometric scanning of specific band of Western blot. The oligonucleotide phosphorothioate (S-ODNs) complementary to the same region of the gene was also synthesized and its growth inhibition effects on BEL-7404 cells were compared with those of unmodified oligomers. ODNs attained their highest effect within 30 hours. The proliferation inhibition rate of the cells didn't increase when cells were cultured in serum free medium. In contrast, the S-ODNs induced inhibition reached comparable level after 96 hours treatment as measured by 3H-thymidine uptake and the effect lasted longer, 1 mumol/L S-ODNs showed a little effect on BEL-7404 cells' proliferation. We concluded that the antisense oligomers directed to mRNA for EG-FR could inhibit the BEL-7404 cells growth by blocking the EGFR gene expression in some degree and the phosphorothioate analogues were more stable than the unmodified ODNs in vitro.

Differences in serum interleukin-6 (IL-6) between healthy dextral and non-dextral subjects.

Serum interleukin-6 (IL-6) was measured in picograms/ml pg/ml using an immunoassay (ELISA) in healthy individuals (n = 148), of whom 128 were classified as dextral and 20 as non-dextral, as per a laterality questionnaire. Only 3 (15%) non-dextral individuals had serum IL-6 levels above the lower limit of the assay sensitivity as compared to 59 (46%) of dextral individuals (P < 0.013). There were no significant correlations between previously determined mitogen stimulated interleukin-2 production and autoantibodies in a subset of the same individuals. While this data does not provide casual information, it adds to the evidence of the asymmetric regulation of immune functions by the cerebral hemispheres.

Expression of (+)-3-PPP binding sites in the PC12 pheochromocytoma cell line.

Phencyclidine binds with high affinity to both PCP and sigma receptors. We investigated whether the clonal cell line PC12 expressed either of these receptors, and found that these cells contain a haloperidol-sensitive (+)-[3H]3-PPP binding site with a KD of 56 nM, but no PCP binding sites. The (+)3-PPP binding sites in PC12 cells displayed a reversed stereoselectivity for the benzomorphan opiates compared to CNS sigma receptors. Neither nerve growth factor nor sodium butyrate treatment affected the expression of either (+)-3-PPP or TCP binding sites in PC12 cells.

Factors modulating filament formation by bovine glial fibrillary acidic protein, the intermediate filament component of astroglial cells.

Glial fibrillary acidic protein (GFAP) is soluble in low ionic strength solutions but shows a strong tendency toward assembly with increasing ionic strength as revealed by electron microscopy and turbidity measurements. Increasing K+, Na+, and Li+ concentrations cause an increase followed by a decrease in GFAP turbidity with a maximum at 200 mM, but their effects are much weaker than effects of divalent cations at the same ionic strength. Ca2+, Mg2+, Mn2+, and Ba2+ promote assembly at millimolar concentrations, and 10 microM Cu2+ causes rapid aggregation. The critical concentration for GFAP assembly was 0.08 +/- 0.04 mg/mL in 2 mM Tris-HCl, 60 mM KCl, and 1 mM CaCl2, pH 6.8. The Mr 38,000 rod domain of GFAP obtained by limited chymotryptic digestion is more soluble in 100 mM imidazole hydrochloride buffer, pH 6.8, than the intact molecule, and removal of the end pieces greatly reduces the ability of GFAP to form filaments. BNPS-skatole (2-[(2-nitrophenyl)sulfenyl]-3-methyl-3-bromoindolenine) treatment releases a Mr 30,000 N-terminus and a Mr 20,000 C-terminus. The Mr 30,000 polypeptide shows a higher affinity than the Mr 20,000 fragment for intact GFAP. Arginine and lysine at low concentrations slightly accelerate GFAP assembly, but above 100 mM both amino acids inhibit assembly. ATP, GTP, CTP, and UTP do not show significant effects on GFAP assembly. Dephosphorylation by alkaline phosphatase slightly reduces the assembly ability of GFAP, but phosphatase-treated GFAP still is assembly competent.

Detection and characterization of some new basic proteins in chicken postsynaptic densities.

Chicken brain postsynaptic density (PSD) polypeptides, obtained by treating synaptosomes with 0.5% Triton X-100 and then further purified on a sucrose gradient, are demonstrated to contain four basic proteins of 76K (pI greater than 9.2), 58K (pI 8.1-8.8, heterogeneous), 40K (pI 9.0), and 24K (pI 8.9). Nonequilibrium pH gradient-sodium dodecyl sulfate two-dimensional gels further reveal six more basic proteins with pI values higher than 9.2: 76K, 52K, 47K, 45K, 36K, and 34K. These basic proteins are a major part of the total chicken PSD polypeptides appearing on the gels. Some of these basic proteins (58K, 52K, 47K, 36K, 24K, and two at 76K) are distinguishable from those of brain mitochondria, the major contaminant. The 40K and 34K proteins may be common mitochondrial polypeptides. The 45K protein is probably a mitochondrial contaminant. A number of proteins including 76K (synapsin I-like protein) and 58K, along with some other minor ones, can be phosphorylated by endogenous protein kinase(s) in the presence of Ca2+, Mg2+, and [gamma-32P]ATP. No PSD basic proteins bind Ca2+.