Unilateral biportal endoscopic spine surgery for lumbar spinal stenosis: a systematic review and meta-analysis.

OBJECTIVE: Lumbar spinal stenosis is the most common spinal degenerative disease in patients over 60 years, and the unilateral biportal endoscopic (UBE) spine surgery treatment of lumbar spinal stenosis (LSS) has achieved preliminary clinical results. This systematic review and meta-analysis aimed to reveal the clinical efficacy of UBE for LSS and provide evidence for clinical practice. MATERIALS AND METHODS: PubMed, Embase, Web of Science, and Cochrane databases were searched for literature. The papers selected were those published from inception till October 2021. The selected pieces of literature were graded for evidence using the Oxford Centre for Evidence-Based Medicine: Levels of Evidence (March 2009). Outcomes measures were operation time, blood loss, complication rate, admission period, Visual Analogue Scale (VAS)-back, VAS-leg, and Oswestry Disability Index (ODI) score, and radiological outcomes. The mean comparisons were based on VAS and ODI scores. RESULTS: A total of 823 patients with a single LSS segment were included from the selected nine studies. There were nine studies comparing UBE clinical outcomes and micro-endoscopic unilateral laminotomy for bilateral decompression (M-ULBD). The meta-analysis revealed that the UBE group had better VAS-leg and -back scores in the first week postoperatively [total: mean difference (MD) = -0.96, 95% confidence interval (CI): -1.19, -0.74, p < 0.00001; total: MD = -1.69, 95% CI: -1.93, -1.45, p < 0.00001], 1st month postoperatively (total: MD = -0.35, 95% CI: -0.61, -0.08, p = 0.01; total: MD = -0.40, 95% CI: -0.68, -0.12, p = 0.005), 6th month postoperatively (total: MD = -0.22, 95% CI: -0.35, -0.08, p = 0.002; total: MD = -0.24, 95% CI: -0.40, -0.07, p = 0.005), and UBE group also performed better in ODI score at 1st month postoperatively (total: MD = -3.36, 95% CI: -4.26, -2.46, p < 0.00001). There was no significant difference in VAS-leg and -back scores between both groups at the 3rd and 12th month postoperatively, and ODI scores did not significantly differ between both groups at 3, 6, and 12 months postoperatively (all p > 0.05). CONCLUSIONS: UBE has achieved good preliminary clinical results and may be a minimally invasive alternative surgery for patients with single segmental LSS.

[The clinical analysis of haploidentical stem cell transplantation in myelodysplastic syndrome-associated acute myeloid leukemia].

Objective: To investigate the prognosis of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in the treatment of acute myeloid leukemia with myelodysplasia-related changes (AML-MRC). Method: The data of 102 patients with high-risk AML in the first complete remission phase (CR1) who received haplo-HSCT from January 2009 to July 2015 in Peking University People's Hospital were retrospectively analyzed. Results: These 102 cases included 17 AML-MRC cases (AML-MRC group) and 85 other types of AML cases (control group). There were 8 males and 9 females in the AML-MRC group, and the median age was 35 (17-61) years. There were 52 males and 33 females in other high-risk AML group, and the median age was 31 (11-60) years. No difference was observed between the two groups after haploidentical stem cell transplantation in the rates of cytomegalovirus, EBV (Epstein-Barr virus), blood flow infection rate and hematopoietic reconstitution (P>0.05). The overall 2-year survival rate after transplantation was 80.8% (95%CI 51.6%-93.4%) and 72.5% (95%CI 62.8%-80.1%) (P=0.650), the disease-free survival rate was 79.4% (95%CI 48.8%-92.9%) and 65.9% (95%CI 54.3%-75.2%) (P=0.573), cumulative recurrence rate was 13.0%(95%CI 1.9%-34.7%) and 13.3%(95%CI 7.0%-21.5%) (P=0.623), and non-relapse mortality was 6.7% (95%CI 0.3%-27.0%) and 20.0% (95%CI 12.0%-29.4%) (P=0.436). Conclusion: The prognosis of haplo-HSCT in patients with AML-MRC in CR(1) is similar to that of other types of high-risk AML patients. Haplo-HSCT is an ideal choice for patients with AML-MRC in CR(1).

[Three dimensional finite element model of a modified posterior cervical single open-door laminoplasty].

Objective: To build a three-dimensional finite element models of a modified posterior cervical single open-door laminoplasty with short-segmental lateral mass screws fusion. Methods: The C(2)-C(7) segmental data were obtained from computed tomography (CT) scans of a male patient with cervical spondylotic myelopathy and spinal stenosis.Three-dimensional finite element models of a modified cervical single open-door laminoplasty (before and after surgery) were constructed by the combination of software package MIMICS, Geomagic and ABAQUS.The models were composed of bony vertebrae, articulating facets, intervertebral disc and associated ligaments.The loads of moments 1.5Nm at different directions (flexion, extension, lateral bending and axial rotation)were applied at preoperative model to calculate intersegmental ranges of motion.The results were compared with the previous studies to verify the validation of the models. Results: Three-dimensional finite element models of the modified cervical single open- door laminoplasty had 102258 elements (preoperative model) and 161 892 elements (postoperative model) respectively, including C(2-7) six bony vertebraes, C(2-3)-C(6-7) five intervertebral disc, main ligaments and lateral mass screws.The intersegmental responses at the preoperative model under the loads of moments 1.5 Nm at different directions were similar to the previous published data. Conclusion: Three-dimensional finite element models of the modified cervical single open- door laminoplasty were successfully established and had a good biological fidelity, which can be used for further study.

Identification of candidate genes in osteoporosis by integrated microarray analysis.

OBJECTIVES: In order to screen the altered gene expression profile in peripheral blood mononuclear cells of patients with osteoporosis, we performed an integrated analysis of the online microarray studies of osteoporosis. METHODS: We searched the Gene Expression Omnibus (GEO) database for microarray studies of peripheral blood mononuclear cells in patients with osteoporosis. Subsequently, we integrated gene expression data sets from multiple microarray studies to obtain differentially expressed genes (DEGs) between patients with osteoporosis and normal controls. Gene function analysis was performed to uncover the functions of identified DEGs. RESULTS: A total of three microarray studies were selected for integrated analysis. In all, 1125 genes were found to be significantly differentially expressed between osteoporosis patients and normal controls, with 373 upregulated and 752 downregulated genes. Positive regulation of the cellular amino metabolic process (gene ontology (GO): 0033240, false discovery rate (FDR) = 1.00E + 00) was significantly enriched under the GO category for biological processes, while for molecular functions, flavin adenine dinucleotide binding (GO: 0050660, FDR = 3.66E-01) and androgen receptor binding (GO: 0050681, FDR = 6.35E-01) were significantly enriched. DEGs were enriched in many osteoporosis-related signalling pathways, including those of mitogen-activated protein kinase (MAPK) and calcium. Protein-protein interaction (PPI) network analysis showed that the significant hub proteins contained ubiquitin specific peptidase 9, X-linked (Degree = 99), ubiquitin specific peptidase 19 (Degree = 57) and ubiquitin conjugating enzyme E2 B (Degree = 57). CONCLUSION: Analysis of gene function of identified differentially expressed genes may expand our understanding of fundamental mechanisms leading to osteoporosis. Moreover, significantly enriched pathways, such as MAPK and calcium, may involve in osteoporosis through osteoblastic differentiation and bone formation.Cite this article: J. J. Li, B. Q. Wang, Q. Fei, Y. Yang, D. Li. Identification of candidate genes in osteoporosis by integrated microarray analysis. Bone Joint Res 2016;5:594-601. DOI: 10.1302/2046-3758.512.BJR-2016-0073.R1.

[Modified percutaneous vertebroplasty assisted by preoperative CT-based digital design: a new technique for osteoporotic vertebral compression fracture].

OBJECTIVE: To report a new technique of modified percutaneous vertebroplasty (PVP) assisted by preoperative CT-based digital design for osteoporotic vertebral compression fracture (OVCF), and to discuss its preliminary clinical results. METHODS: Thoracolumbar spine segment data (Dicom format) were obtained from lamellar CT scanning of seven old female or male with single OVCF. A three-dimensional model of thoracolumbar spine and simulative PVP models (via double transpedicular approach) were built in the Mimics software. With the help of a preoperative transparent marker located at the back midline skin and preoperative digital design by Mimics software, the needle insert point and needle direction in every patient were established. The surgical time, the number of intraoperative radiation perspective, bone cement filling condition in fracture vertebra, intraoperative complications and visual analogue scale (VAS) scores before and after surgery were recorded to evaluate the preliminary clinical results after modified PVP. RESULTS: The puncture process during PVP was in high accordance with the preoperative digital design by Mimics software in seven cases of single OVCF with the average age of 78 years old. The operation time was only 16.57±2.07 minutes and the intraoperative radiation perspective numbers were less than ten (7.86±1.68) times. The bone cement filling in all fracture vertebras were good and no surgical complications such as spine cord injury and cement leakage were founded. The VAS scores before and after surgery were 8.57±0.53 points and 1.43±0.53 point (P=0.000), respectively. CONCLUSION: Percutaneous vertebroplasty (PVP) assisted by preoperative CT-based digital design has high accuracy, which is expected to reduce operation time, intraoperative radiation exposure and the surgical complications related to puncture failure.

Can hepatitis B virus DNA in semen be predicted by serum levels of hepatitis B virus DNA, HBeAg, and HBsAg in chronically infected men from infertile couples?

Hepatitis B virus (HBV) in semen is important for father-to-child transmission of HBV and has adverse effects on sperm quality. However, risk factors associated with HBV in semen remain unclear. Serum HBV DNA and hepatitis B e antigen (HBeAg) levels may pose a risk on HBV in semen. This study aims to examine whether serum HBV DNA, HBeAg, and hepatitis B surface antigen (HBsAg) level were associated with HBV DNA in semen. 151 male patients chronically infected with HBV from infertile couples were included. Serum HBsAg and HBeAg were determined using an electrochemiluminescence immune assay (ECLIA). Serum and seminal plasma HBV DNA were detected by the QIAGEN Real-Time HBV DNA assay. Of 151 patients, 143 (94.7%) were serum HBV DNA-positive and 65 (43.0%) were seminal plasma HBV DNA-positive. Serum HBV DNA and HBeAg level of seminal plasma HBV DNA-positive patients were significantly higher (p < 0.001) as compared with those of seminal plasma HBV DNA-negative patients, HBsAg level of seminal plasma HBV DNA-positive patients was significantly lower (p < 0.001) compared with that of seminal plasma HBV DNA-negative patients. The best serum HBV DNA, HBeAg, and HBsAg value for discriminating between seminal plasma HBV DNA-positive and HBV DNA-negative patients were ≥6.9 log10 IU/mL (sensitivity 100.0%, specificity 90.7%), >14.8 S/CO (sensitivity 96.9%, specificity 81.5%), and <1791.5 S/CO (sensitivity 81.5%, specificity 81.2%), respectively. The combination of serum HBV DNA and HBeAg had high diagnostic sensitivity (100.0%) and specificity (95.4%) for the presence of HBV DNA in semen. As such, these serum markers especially the combination of HBV DNA and HBeAg are useful predictors of the presence of HBV DNA in semen in HBV chronically infected men from infertile couples.

A novel water-soluble sulfonated porphyrin fluorescence sensor for sensitive assays of H2O2 and glucose.

Water soluble porphyrins have many perfect analytical figures of merit. A water-soluble sulfonated porphyrin (H2TEHPPS) was used to build a novel platform for sensitive assays of hydrogen peroxide and glucose based on the different effects of Fe(2+) and Fe(3+) on H2TEHPPS. H2O2 or Fe(2+) alone cannot induce a fluorescence change in H2TEHPPS, but Fe(3+) can quench the fluorescence of H2TEHPPS significantly. Interestingly, glucose is oxidized to gluconolactone by GOD and generates an equivalent hydrogen peroxide, and the produced H2O2 also oxidizes Fe(2+) to Fe(3+) and causes the fluorescence quenching of H2TEHPPS. According to this, a sensitive sensor for hydrogen peroxide and glucose has been demonstrated, which can determine H2O2 and glucose in a relative simple and sensitive way. The detection limits were 1.3 × 10(-7) M and 3.2 × 10(-7) M for H2O2 and glucose, respectively. In addition, the glucose in serum samples was determined successfully using this sensing platform. It is also noteworthy that H2O2 can be released in almost all oxidations catalyzed by oxidases, which suggests that this newly proposed H2O2 probe can be readily extended to sense other oxidases and their specific substrates.

Two novel mutations in the Spastin gene of Chinese patients with hereditary spastic paraplegia.

BACKGROUND AND PURPOSE: Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative diseases. Mutations in the spastin (SPG4) gene are responsible for approximately 40% of autosomal dominant HSP (AD-HSP) and 6.5-18% of sporadic cases. METHODS: Spastin mutations were screened in 11 AD-HSP families and 11 sporadic cases by direct sequencing and MLPA assay. Novel mutations were detected in 100 healthy controls by PCR-RFLP. RESULTS: We identified seven different spastin mutations in five probands and one sporadic patient. Two of seven mutations were novel. The c.458delT was a pathogenic mutation, but the effect of c.1724 G>T remained unknown. CONCLUSIONS: This study allowed us to estimate the frequency of the SPG4 mutations in Chinese at 45% (5/11) in families with AD-HSP and 9% (1/11) in sporadic cases. In addition, our data showed p.T614I was not associated with congenital arachnoid cysts.

Analysis of Lingo1 variant in sporadic and familial essential tremor among Asians.

OBJECTIVE - Genome-wide association study (GWAS) has identified a variant in LINGO1 (rs9652490) that increases the risk of essential tremor (ET) among Caucasians. It has been suggested that among Asians, the risk variant is relevant only for the familial forms of ET. We investigated the association of the rs9652490 variant with sporadic and familial ET in a Chinese population and conducted a pooled analysis to compare the potential differential effect between sporadic and familial ET. METHODS - rs9652490 was genotyped by direct sequencing in 117 ET and 160 controls in a Chinese population. Previous published data from another Asian population were included in the meta-analysis. RESULT - There were no significant differences in the minor allele frequency and genotype frequency between ET and controls in our Chinese population. However, in the pooled analysis involving 1201 subjects, patients with ET had a higher proportion of GG genotype compared to controls. Logistic regression analysis revealed that G allele increased the risk of ET via a recessive model. In both familial ET and sporadic ET, the G allele increased the risk via a recessive model. CONCLUSION - While we could not demonstrate a significant association of the rs9652490 variant in our own study, pooled analysis of a much larger cohort revealed for the first time that the variant increased the risk in both familial and sporadic forms of ET among Asians, though the effect was stronger in familial ET.

The GIGYF2 variants are not associated with Parkinson's disease in the mainland Chinese population.

In order to determine the prevalence of GIGYF2 (Grb10-Interacting GYF Protein 2) variants in the Chinese population and to better understand the association between GIGYF2 and Parkinson's disease (PD), we conducted the genetic screening of GIGYF2 in the Chinese population. Twelve exonic variants were identified in 52 familial PD probands and 56 healthy controls. Non-synonymous point variants (Thr25Ala, Asn457Th and Pro460Th) were analyzed in 510 PD patients and 481 healthy controls of Chinese Han ethnicity. The insertion and deletion variants in Exon 25 (Ins Q 1212, Ins QQ 1217, Del Q 1210, Del Q 1216 and Del PPQ1217_1219) are not related to the onset of familial PD. Our data indicate the GIGYF2 variants are not associated with PD in the mainland Chinese Population.

The AdLMP-1 transfection in two different cells; AF cells, chondrocytes as potential cell therapy candidates for disc degeneration.

BACKGROUND: LMP-1 is known to increase proteoglycan production through the upregulating the BMPs and it is also known that BMP-2 acts on anulus fibrosus cells and chondrocytes to increase proteoglycan production. METHOD: We carried out an experiment, the effect of AdLMP-1 transfection on AF cells and chondrocytes in the production of sulfated-glycosaminoglycans, mRNA expression (aggrecan, type I, II collagen, LMP-1, BMP-2, and BMP-7), and immunofluorescence staining. AF cells and chondrocytes were grown in monolayer and treated for 6 days with AdLMP1-green fluorescence protein (GFP) (10, 20, and 30 multiplicity of infection [MOI]). After 6 days, the sGAG content in the media was quantified using 1,9-dimethylmethylene blue staining. The mRNA expression was measured with real-time PCR after 20 MOI infection of AdLMP1-GFP. The each cells treated with 20 MOI infection of AdGFP was used as a control group for the mRNA expression. The each cell group was immunofluorescence stained with each antibodies in the chamber slide at 3 x 10(4) cells/chamber. FINDINGS: 1) The sGAG production was maximum in 20 MOI AdLMP1-GFP infection on the AdLMP-1 treatment for both of AF cells and chondrocytes. 2) The mRNA expression of aggrecan, type I collagen, type II collagen, LMP-1, BMP-2, and BMP-7 is increased in both AF cells and chondrocytes in 20 MOI AdLMP1-GFP infection. 3) On the immunofluorescence staining results, the positive immunofluorescence stained cell numbers are increased after 20 MOI AdLMP1-GFP infection concordant with upregulation of mRNA expression. CONCLUSIONS: The AdLMP-1 treatments in AF cells and chondrocytes may be useful for cell transplantation therapy in disc degeneration.

The mitotic checkpoint kinase NEK2A regulates kinetochore microtubule attachment stability.

Loss or gain of whole chromosome, the form of chromosome instability commonly associated with cancers is thought to arise from aberrant chromosome segregation during cell division. Chromosome segregation in mitosis is orchestrated by the interaction of kinetochores with spindle microtubules. Our studies show that NEK2A is a kinetochore-associated protein kinase essential for faithful chromosome segregation. However, it was unclear how NEK2A ensures accurate chromosome segregation in mitosis. Here we show that NEK2A-mediated Hec1 (highly expressed in cancer) phosphorylation is essential for faithful kinetochore microtubule attachments in mitosis. Using phospho-specific antibody, our studies show that NEK2A phosphorylates Hec1 at Ser165 during mitosis. Although such phosphorylation is not required for assembly of Hec1 to the kinetochore, expression of non-phosphorylatable mutant Hec1(S165) perturbed chromosome congression and resulted in a dramatic increase in microtubule attachment errors, including syntelic and monotelic attachments. Our in vitro reconstitution experiment demonstrated that Hec1 binds to microtubule in low affinity and phosphorylation by NEK2A, which prevents aberrant kinetochore-microtubule connections in vivo, increases the affinity of the Ndc80 complex for microtubules in vitro. Thus, our studies illustrate a novel regulatory mechanism in which NEK2A kinase operates a faithful chromosome attachment to spindle microtubule, which prevents chromosome instability during cell division.

Afferent arteriolar adenosine A2a receptors are coupled to KATP in in vitro perfused hydronephrotic rat kidney.

Adenosine is known to exert dual actions on the afferent arteriole, eliciting vasoconstriction, by activating A1 receptors, and vasodilation at higher concentrations, by activating lower-affinity A2 receptors. We could demonstrate both of these known adenosine responses in the in vitro perfused hydronephrotic rat kidney. Thus, 1.0 microM adenosine elicited a transient vasoconstriction blocked by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), and 10-30 microM adenosine reversed KCl-induced vasoconstriction. However, when we examined the effects of adenosine on pressure-induced afferent arteriolar vasoconstriction, we observed a third action. In this setting, a high-affinity adenosine vasodilatory response was observed at concentrations of 10-300 nM. This response was blocked by both 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3, 5]triazin-5-yl-amino]ethyl)phenol (ZM-241385) and glibenclamide and was mimicked by 2-phenylaminoadenosine (CV-1808) (IC50 of 100 nM), implicating adenosine A2a receptors coupled to ATP-sensitive K channels (KATP). Like adenosine, 5'-N-ethylcarboxamidoadenosine (NECA) elicited both glibenclamide-sensitive and glibenclamide-insensitive vasodilatory responses. The order of potency for the glibenclamide-sensitive component was NECA > adenosine = CV-1808. Our findings suggest that, in addition to the previously described adenosine A1 and low-affinity A2b receptors, the renal microvasculature is also capable of expressing high-affinity adenosine A2a receptors. This renal adenosine receptor elicits afferent arteriolar vasodilation at submicromolar adenosine levels by activating KATP.

[The thumb reconstruction by transferring the injured index finger with pedicles].

OBJECTIVE: In order to inquire the methods of thumb reconstruction by transferring the index finger with incomplete conditions of nerve or blood vessels. METHODS: From April 1987 to October 1997, 6 cases were treated by 3 kinds of operative methods according to the damage type of thumb and complications injures of the rest of hand: 1. transferring the index finger with pedicle without proximal phalanx, 2. transferring the index finger with palmar nerve and blood vessels, and dorsal skin pedicle, 3. transferring the index finger with compound pedicle. RESULTS: All 6 cases of thumb reconstruction were successful. Followed up 6 months to 2 years, the pinching and gribing functions in 6 cases were completely recovered, and the sensation were partly recovered. CONCLUSION: The operative method of thumb reconstruction had following advantages: Simple operation, high survival rate and certain function recovery. It can enlarge the indications of thumb reconstruction.

[The detection of basement membrane and dendritic cells in laryngeal carcinoma].

The state of basement membrane(BM) and dendritic cells(DC) were observed by immunohistochemical methods with the use of anti-laminin antibody, anti-type IV collagen antibody, anti-S-100 protein antibody in 68 cases of laryngeal carcinoma and 21 cases of non-cancer laryngeal tissues. The results showed that among 68 patients with laryngeal carcinoma 39 cases had discontinuous BM. A continuous, linear BM was found mostly in normal larynx, atypia hyperplasia and papilloma, only 3 cases had discontinuous BM. 43 positive DC were detected in 68 cases of laryngeal carcinoma. There were rarely positive DC in non-cancer laryngeal tissues. The poorer the differentiation of carcinoma, the more the discontinuous BM and the lesser the number of DC. The discontinuous BM and DC(-) were seen more in advanced stages of carcinoma. The five-year survival rate in patients with continuous BM was significantly higher than that in patients with discontinuous BM, the five-year survival rate in patients with DC positive was also higher than that in patients with DC negative; the survival rate was highest in patients with continuous BM and DC positive. Our results indicated that the detection of the state of BM and dendritic cells were of value to the prognostic analysis in patients with laryngeal carcinoma.

Plasma membrane p180, which insulin receptor phosphorylates in vivo, is not a tyrosine kinase.

The earliest substrates to the transmembrane insulin receptor tyrosine kinase, that would function in insulin signalling, are likely to be associated with the plasma membrane. Rat liver plasma membrane 180,000 M(r) protein (p180) is a substrate to the insulin receptor in vitro [Goren et al. (1990) Cellular Signalling 2, 537-555]. The question as to whether p180 is a substrate in vivo was addressed. Half ml 0.9% NaCl or 500 micrograms insulin was injected into rat livers. Purified plasma membrane glycoproteins from the livers were assayed for in vitro phosphorylation reaction products and endogenous tyrosine-phosphorylated proteins. Membranes from insulin-injected rat livers contained phosphorylated p180 and phosphorylated insulin receptor beta-subunit, whereas saline-injected rat liver membranes contained neither. These data suggested that p180 is an in vivo substrate to the insulin receptor. In vitro p180 is tyrosine-phosphorylated in the absence of insulin. p180, therefore, may be the epidermal growth factor (EGF) receptor or another tyrosine kinase that could be part of a phosphorylation cascade initiated by insulin. Two different experiments suggested that p180 is not the EGF receptor: (i) two-dimensional gel electrophoresis (first dimension--non-equilibrium pH-gradient gel electrophoresis) indicated that p180 is a more basic glycoprotein than EGF receptor; and (ii) based on reverse-phase high pressure liquid chromatography, the tryptic-phosphopeptides of carboxymethyl-Sepharose-purified phosphorylated-p180 were different from those of A431 cell phosphorylated-EGF receptor. Similarly, two different experiments demonstrated that p180 is not a tyrosine kinase: (i) gel-permeation chromatography separated the insulin receptor from p180 and only insulin receptor was autophosphorylated in vitro; and (ii) membrane proteins not bound to immobilized ATP contained p180. Thus, p180 can associate with the insulin receptor and be phosphorylated in vitro and in vivo; however, p180 does not function in an insulin receptor-mediated phosphorylation cascade.

The realization of a pulsatile implantable impeller pump with low hemolysis.

A pulsatile implantable impeller pump with low hemolysis was developed without markedly increasing the complexity of the system compared with the nonpulsatile pump. The key to the question is to design a three-dimensional impeller with twisted vanes, compacted by an axial helical spiral and a radial logarithmic spiral so as to reduce the turbulent shear in the pump as the impeller changes its rotations per minute periodically to generate a physiologic pulsatile flow. Both mathematic computation of velocity distribution in the impeller and geometric illustration of the velocity triangle at the top of the vane have demonstrated that the peripheral velocity variation of blood cells in a twisted impeller will be less than that in an untwisted impeller. Thus, the main mechanical factor of hemolysis in the impeller pump, namely, the turbulent shear, should be reduced because it is proportional to the product of velocity variations measured in two perpendicular directions. In the in vitro experiments, the pump delivered 4 L/min mean flow at 100 mm Hg mean pressure (pulsed between 80-120 mm Hg) for more than 3 h in a circulatory model containing 700 ml of fresh citrated porcine blood. Every half hour, the free hemoglobin level in the plasma was tested, and the resulting index of hemolysis was about 0.020, slightly more than that of a nonpulsatile impeller pump developed in Shanghai. To compare hemolysis, the index of hemolysis of this pump is about 1/6 of that of the self-made diaphragm pump and 1/13 of that of the Polystan Pulsatile Pump.(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical treatment of biliary tract disease in elderly patients].

A retrospective study 94 cases of elderly patients with biliary tract disease. The overall postoperative mortality rate was 6.4%. Among the 94 cases there were 50 cases of acute cholecystitis, of which 15 cases were complicated by acute obstructive suppurative cholangitis, and 44 cases of chronic cholecystitis. 80 cases had gallstones (85.1%). Associated diseases were found in 56 cases (59.6%) before operation, most of them were cardiovascular diseases (53.2%). During operation 23 cases were monitored by ECG, and abnormal ECG developed in 6 cases although the operations were all carried out uneventfully. It is suggested that after adequate preoperative preparation, aggressive surgical intervention should be considered for acute biliary tract disease in elderly patients.

Haemolysis test of non-pulsatile and pulsatile impeller blood pumps.

Non-pulsatile and pulsatile impeller blood pumps have been developed. The non-pulsatile pump was compared with the Shanghai and Sarns 7000 roller pumps for haemolysis. Similarly, the pulsatile pump was compared with a pneumatic diaphragm pump and the Polystan pulsatile pump. In each test, one impeller pump and the pump it was being compared with were connected to two identical circulatory systems with the same volume of fresh citrated porcine blood, delivered at the same pressure and flow for several hours. Every half hour the free haemoglobin was measured and the index of haemolysis (IH) calculated. The mean IH of the non-pulsatile impeller pump was about 18% of the Shanghai roller pump and 29% of the Sarns 7000 roller pump; the IH of the pulsatile impeller pump was 16% of the diaphragm pump and 8% of the Polystan pulsatile pump.