[Association between blood pressure during 12-28 weeks gestation and pre-eclampsia: predictive value of blood pressure trajectories constructed by latent class growth modeling]

Objective: To explore the associations between blood pressure trajectories during pregnancy and risk of future pre-eclampsia in a large cohort enrolling pregnant women at gestational age of ~12 weeks from community hospitals in Tianjin. Latent class growth modeling (LCGM) was used to model the blood pressure trajectories. Methods: This was a large prospective cohort study. The study enrolled pregnant women of ~12 weeks of gestation in 19 community hospitals in Tianjin from November 1, 2016 to May 30, 2018. We obtained related information during 5 antepartum examinations before gestational week 28, i.e., week 12, week 16, week 20, week 24 and week 28. LCGM was used to model longitudinal systolic (SBP) and diastolic blood pressure (DBP) trajectories. For the association study, the predictors were set as SBP and DBP trajectory membership (built separately), the outcome was defined as the occurrence of preeclampsia after 28 weeks of gestation. Results: A total of 5 809 cases with known pregnant outcomes were documented. After excluding 249 cases per exclusion criteria, 5 560 cases with singleton pregnancy were included for final analysis. There were 128 cases preeclampsia and 106 cases gestational hypertension in this cohort. Univariate logistic regression and multivariate logistic regression showed the higher baseline SBP level and DBP level were related with increased risk of preeclampsia. Four distinctive SBP trajectories and DBP trajectories from 12 weeks to 28 weeks of gestation were identified by LCGM. After controlling for potential confounders (baseline BMI, being primipara or not, white blood cell counts, hemoglobin level, platelet counts and alanine aminotransferase level), the OR for SBP latent classification trajectory_ 4 was 4.023 (95%CI: 2.368 to 6.835, P<0.001), and the OR for SBP latent classification trajectory_3 was 1.854 (95%CI: 1.223 to 2.811, P=0.004). Logistic regression showed that: using the DBP latent classification trajectory_1 as the reference group, the OR for DBP latent classification trajectory_4 was 4.100 (95%CI: 2.571 to 6.538, P<0.001), and 2.632 (95%CI: 1.570 to 4.414, P<0.001) for DBP latent classification trajectory_2. After controlling for potential confounders (baseline BMI, being primipara or not, white blood cell counts, hemoglobin level, platelet counts and alanine aminotransferase level), the OR for DBP_traj_4 was 2.527 (95%CI: 1.534 to 4.162, P<0.001), and the OR for DBP_traj_3 was 1.297 (95%CI: 0.790 to 2.128, P=0.303), and 2.238 (95%CI: 1.328 to 3.772, P=0.002) for DBP_traj_2. Therefore, BP trajectories from 12 weeks to 28 weeks identified by LCGM served as novel risk factors that independently associated with the occurrence of preeclampsia. Receiver operating characteristic (ROC) curve analysis showed incremental diagnostic performance by combing baseline blood pressure levels with blood pressure trajectories. Conclusion: By applying LCGM, we for the first time identified distinctive BP trajectories from gestational week 12 to 28, which can independently predict the development of preeclampsia after 28 weeks of gestation.

[A retrospective analysis of 200-cases of otosclerosis]

Objective:To identify the audiological improvement postoperatively and improve the understand of otosclerosis for a better performance of personalized surgical treatment.Method:We retrospectively reviewed a series of 200 cases after surgery for ototsclerosis.The clinical characteristics,pre-and postoperative audiometric results,signs of Carhart notch, Gelle test and the characteristics of high-resolution computed tomography of temporal bone were analyzed retrospectively.Result:73% of patients had tinnitus, while 4% had sense of ear fullness,80.79% had Carhart notch,92.09% had negative result in Gelle test and 45.66% had positive signs on computed tomography. 68% of the patients revealed a type A tympanogram with only 22% type As.Fifty-six cases with laser stapedotomy achieved a the air bone gap at 250 Hz,500 Hz,1 kHz,2 kHz and 4 kHz of 25.54,16.25,13.75,6.34,15.96 dB,respectively. The bone conduction thresholds at 250 Hz,500 Hz,1 kHz,2 kHz improved 2.05,1.51,3.75 and 3.93 dB,respectively. At 4 kHz, bone conduction threshold increased by 1.34 dB.The improvement of bone conduction threshold at 250 Hz,1 kHz,2 kHz was significantly but for the revisions at 500 Hz and 4 kHz.Conclusion:The diagnosis of otosclerosis should be based on the combination of medical history, pure tone audiometry, tympanometry, Carhart notch, Gelle test and high resolution computed tomography of temporal bone.Surgical technique of stapedotomy with Piston artificial auditory ossicle implantation could improve not only the air conduction threshold, but also the bone conduction threshold at 250 Hz,1 kHz,2 kHz.

An outbreak of Candida parapsilosis fungemia among preterm infants

In this article, we describe the first outbreak of Candida parapsilosis fungemia in our hospital. We examined a cluster of four nosocomial cases of C. parapsilosis fungemia that occurred in the neonatal intensive care unit (NICU) of the Affiliated Xingtai People's Hospital of Hebei Medical University over a two-week period. We ascertained patient parameters including clinical characteristics, blood and sputum cultures, and drug sensitivity test results. Cultures from eight blood samples obtained from the four infected preterm infants showed identical characteristics and were identified as C. parapsilosis. In order to determine the infection-related factors and to control the spread of the infection among the population, we immediately initiated the emergency plan. All four of the preterm infants recovered from the infection; there were no deaths. Outbreaks of C. parapsilosis, mostly involving preterm infants of very low birth weight or extremely low birth weight, can and do occur in NICUs. Cultures prepared using multiple samples taken from different patients contribute to a more definitive diagnosis. Established measures that control and prevent the infection, as well as effective and comprehensive treatments, can lead to a favorable outcome. That is to say, improving both disinfection and isolation, as well as interrupting the pathway of transmission, is the key to controlling the spread of infection.

Free vascularised fibular graft for post-traumatic osteonecrosis of the femoral head in teenage patients

Free vascularised fibular grafting has been reported to be successful for adult patients with osteonecrosis of the femoral head (ONFH). However, its benefit in teenage patients with post-traumatic ONFH has not been determined. We evaluated the effectiveness of free vascularised fibular grafting in the treatment of this condition in children and adolescents. We retrospectively analysed 28 hips in 28 patients in whom an osteonecrotic femoral head had been treated with free vascularised fibular grafting between 2002 and 2008. Their mean age was 16.3 years (13 to 19). The stage of the disease at time of surgery, and results of treatment including pre- and post-operative Harris hip scores, were studied. We defined clinical failure as conversion to total hip replacement. All patients were followed up for a mean of four years (2 to 7). The mean Harris hip score improved from 60.4 (37 to 84) pre-operatively to 94.2 (87 to 100) at final follow-up. At the latest follow-up we found improved or unchanged radiographs in all four initially stage II hips and in 23 of 24 stage III or IV hips. Only one hip (stage V) deteriorated. No patient underwent total hip replacement. Free vascularised fibular grafting is indicated for the treatment of post-traumatic ONFH in teenage patients.

Oriental HLA-A*11:90 detected in a Taiwanese cord blood sample and the haplotype in association with A*11:90 allele

We report here an HLA-A allele, A*11:90, found in a Taiwanese cord blood sample using DNA sequence-based typing (SBT) protocol after observing an anomalous reaction pattern in a sequence-specific oligonucleotide (SSO) typing exercise. The sequence of A*11:90 is identical to A*11:01:01, the most predominant A*11 variant in Taiwanese, in exon 2 but differs from A*11:01:01 in exon 3 by two nucleotide substitutions at codon 163 (c.487C>G and c.488G>A), resulting R163E. In comparison with the sequence of A*11:02:01, the second most predominant subtype of A*11 in Taiwanese A*11:90 has one nucleotide difference at codon 19 (c.55A>G) in exon 2 resulting K19E and two nucleotides variations at codon 163 (c.487C>G and c.488G>A) in exon 3 resulting R163E. HLA-A*11:90-B*40:02-DRB1*11:01 is the deduced probable HLA haplotype in association with A*11:90. The generation of A*11:90 is thought to involve a DNA recombination event between alleles A*11:01:01 and A*80:01 where A*80:01 donated a fragment of the DNA sequence (from n.t. 487 to n.t. 497) to the recipient sequence of A*11:01:01.

Proteomic identification of differentially expressed proteins in curcumin-treated MCF-7 cells

Curcumin (CM), a well-known dietary pigment derived from Curcuma longa L., possess anticancer activities against a variety of tumors including human breast carcinoma. In combination with docetaxel, CM has been used in breast cancer management in the clinic. In order to explore the possible mechanism of anticancer activity of CM, in the present study, we aimed to identify proteins involved in the anticancer activity of CM in human breast cancer cell line MCF-7 using the two-dimensional electrophoresis (2-DE)-based proteomic analysis. MCF-7 cells were cultured at 37°C in an atmosphere of 5.0% CO(2). All the following experiments were repeated three times. Cell viability assay showed that after a 48-h incubation CM dose-dependently inhibited cell growth with an IC(50) value of 47.42 μM. Treatment of CM at 47.42 μM for 48 h induced apoptosis as determined by nuclear morphologic changes of Hoechst stained cells and flow cytometric analysis of Annexin V-FITC/PI stained cells. Proteomic analysis identified 12 differentially expressed proteins which contributed to multiple functional activities such as DNA transcription, mRNA splicing and translation, amino acid synthesis, protein synthesis, folding and degradation, lipid metabolism, glycolysis, and cell motility. Among them 7 proteins were up-regulated and 5 down-regulated. The up-regulated ones were verified by quantitative real-time PCR. The down-regulated proteins, TDP-43, SF2/ASF and eIF3i, as well as up-regulated ones, 3-PGDH, ERP29, and platelet-activating factor acetylhydrolase IB subunit beta positively contribute to the anticancer activity of CM in MCF-7 cells. These molecules are implicated in the bioactivities of CM for the first time. The findings of this study would shed new insights for systematically understanding the mechanisms of CM in breast cancer intervention.

Reverse LISS plating for intertrochanteric hip fractures in elderly patients

Background

Fractures of the intertrochanteric hip are common and the treatment of unstable fractures generally requires an operative approach. In elderly patients, osteoporosis makes internal fixation problematic and frequently contributes to failed fixation and poor clinical results. We have attempted to apply the Less Invasive Stabilization System (LISS) in reverse position for the repair of intertrochanteric hip fractures in elderly patients with osteoporotic bones. A retrospective review is presented of the cases of 28 elderly patients with stable and unstable fractures of the intertrochanteric hip treated using the reverse LISS.

Methods

We treated 28 elderly patients with a mean age of 82.3 years. According to the Evens classification, there were 2 Type I fractures, 2 Type II fractures, 3 Type III fractures, 13 Type IV fractures, 6 Type V fractures and 2 Type R fractures. All fractures were treated using the reverse LISS. Radiographic and clinical evidence of functional outcome and complications were evaluated.

Results

Mean perioperative blood loss was 92.4 milliliters (range 35 to 245 milliliters), and the mean postoperative hospital stay was 8.7 days (range 3 to 14 days).

Complications included one minor wound hematoma. Radiographically, no collapses, screw cutouts, or head penetrations were seen. All surviving patients (28 of 28; 100 percent) had uneventful fracture healing with union achieved by six months in all patients.

Conclusions

Use of the Reverse LISS plating for intertrochanteric hip fractures resulted in event-free fracture healing.

Changes in Femoral Head Blood Supply and Vascular Endothelial Growth Factor in Rabbits with Steroid-induced Osteonecrosis

The molecular aetiology of steroid-induced osteonecrosis (ON) is unclear. The aim of this study was to investigate changes in the femoral head blood supply and vascular endothelial growth factor (VEGF) protein levels following steroid-induced ON of rabbit femoral heads in the early stage of the disease, and to investigate a possible mechanism for ON. Using a classic protocol, ON was induced in 30 male 28-week old New Zealand white rabbits. An additional 15 untreated rabbits served as controls. Change of blood supply in the proximal femur was assessed by dynamic magnetic resonance imaging and microangiography. The VEGF protein and mRNA levels were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. After 6 weeks, the results indicated that VEGF protein and mRNA levels were significantly lower and femoral head blood supply had also decreased significantly in ON+ rabbits compared with controls. The down-regulation of VEGF may play a critical role in the disease process of ON.

Treatment of femoral head osteonecrosis in patients with systemic lupus erythematosus by free vascularised fibular grafting

The purpose of this study was to review the radiographs of symptomatic femoral head osteonecrosis in patients with systemic lupus erythematosus (SLE) and to assess the results of treatment using free vascularised fibular grafting. We retrospectively reviewed 50 patients (80 hips) with SLE who underwent free vascularised fibular grafting for osteonecrosis of the femoral head. All patients were followed up for at least 2 or more years (average, 4.3 years). The mean Harris hip score improved from 72 to 88. At the latest follow-up, we found improved or unchanged radiographs in 12 of initially Stage II hips and in 60 of 64 Stage III or IV hips. No hips failed treatment and underwent total hip arthroplasty. The data suggest that free vascularised fibular grafting was successful in maintaining joint function and in delaying the need for joint replacement procedure.

Curative effect and safety of vascularized fibula grafting in renal transplant recipients with osteonecrosis of the femoral head: three case reports

Osteonecrosis of the femoral head is a common and severe complication after renal transplantation. It is characterized by deterioration of hip joint function, which impairs quality of life. We present 3 renal transplant case reports of patients with osteonecrosis of the femoral head who underwent free vascularized fibular grafting at our hospital. Follow-up was from 1(1/2) to 2 years. All 3 patients exhibited good recovery with substantial improvement in joint function. Intraoperative and postoperative findings demonstrated the safety of this surgical procedure.

The regenerative effect of platelet-rich plasma on healing in large osteochondral defects

Platelet-rich plasma (PRP), a platelet concentrate made of autogenous blood, has been used to improve bone and soft tissue defect healing in recent years. The aim of this study was to assess the effect of PRP on articular cartilage defects in a rabbit model. Forty-eight osteochondral defects created in the femoropatellar groove were (a) left untreated, (b) treated with autogenous PRP in a poly-lactic-glycolic acid (PLGA), or (c) with PLGA alone. Platelets were enriched 5.12-fold compared to normal blood in the PRP. After four and 12 weeks, the explanted tissue specimens were assessed by macroscopic examination, micro-computed tomography, and histological evaluation. Macroscopic examination, micro-computed tomography and histology of the newly formed cartilage and bone in the defect differ significantly between the PRP-treated and the untreated groups, and stimulatory effect of PRP on osteochondral formation was observed. In conclusion, PRP in PLGA improves osteochondral healing in a rabbit model.

The effect of grain size of rock phosphate amendment on metal immobilization in contaminated soils

When rock phosphates (RP) are used to remediate Pb-contaminated soils, their effectiveness is likely affected by their grain size. In this study, the effect of grain size of rock phosphate on the effectiveness of heavy metal immobilization in two contaminated soils was measured in pot experiment. Rock phosphate was used with four different grain sizes: <35, 35-72, 72-133 and 133-266microm. The application rate of rock phosphate in two soils was determined based on P/metals (Pb, Zn, Cu and Cd) molar ratio of 5.0 in the soils. The results showed that rock phosphate of the smallest grain size (<35microm) was superior to all of other grain sizes more than 35microm for reducing uptake in plant (Brassica oleracea L.) shoots for Cd (19.6-50.0%), Pb (21.9-51.4%) and Zn (22.4-34.6%), respectively, as compared with the soil without application of rock phosphate. Sequential extraction analysis indicated that rock phosphate was most effective for soil Pb to induced transformation from non-residual fractions to a residual fraction than that for Zn and Cd. Such transformation was probably through dissolution of Pb associated with exchangeable (EX), organic fraction (OC), acidic fraction (AC) and amorphous Fe and Al oxides-bound (OX) fraction and precipitation of pyromorphite-like minerals. Results suggested that the rock phosphate with small grain size was superior to that with large grain size for in situ remediation technology.

Soil to plant transfer of 238U, 226Ra and 232Th on a uranium mining-impacted soil from southeastern China

Both soil and plant samples of nine different plant species grown in soils from southeastern China contaminated with uranium mine tailings were analyzed for the plant uptake and translocation of 238U, 226Ra and 232Th. Substantial differences were observed in the soil-plant transfer factor (TF) among these radionuclides and plant species. Lupine (Lupinus albus) exhibited the highest uptake of 238U (TF value of 3.7x10(-2)), while Chinese mustard (Brassica chinensis) had the least (0.5x10(-2)). However, in the case of 226Ra and 232Th, the highest TFs were observed for white clover (Trifolium pratense) (3.4x10(-2)) and ryegrass (Lolium perenne) (2.1x10(-3)), respectively. 232Th in the tailings/soil mixture was less available for plant uptake than 226Ra or 238U, and this was especially evident for Chinese mustard and corn (Zea mays). The root/shoot (R/S) ratios obtained for different plants and radionuclides shown that Indian mustard had the smallest R/S ratios for both 226Ra (5.3+/-1.2) and 232Th (5.3+/-1.7), while the smallest R/S ratio for 238U was observed in clover (2.8+/-0.9).

Surfactant free fabrication of polymeric nanoparticles by combined liquid–liquid phase separation and solvent/nonsolvent mixing technology

It is generally agreed that, in most cases, surfactants are required to obtain stable polymeric nanoparticle dispersions. Here, we report a method which can be used to produce surfactant free yet stable polymeric nanoparticle dispersions. This method is based on explored mechanism of selective solvation of nanoparticles and EPD (electron pair donor)/EPA (electron pair acceptor) complexes formed among solvent and nonsolvent molecules. Using polyimide P84 (copolyimide 3,3(') 4,4(')-benzophenone tetracarboxylic dianhydride and 80% methylphenylene diamine+20% methylene dianiline) as the model polymer, this mechanism was realized through a combined liquid-liquid phase separation and solvent/nonsolvent mixing technology. Surfactant-free polyimide nanoparticles (<100 nm) were produced. Experimental details and principles of this technology were given based on the ternary diffusion, the liquid-liquid phase separation and the advanced nucleation and growth theory. Two types of methods [denoted as the forward titration method and the backward titration (BT) method] were examined. It was found that the BT method is extremely helpful to prepare polyimide nanoparticles (<100 nm). As another important aspect, explored stabilization mechanism of the resultant nanoparticle dispersions was supported by the comparative experiments, implying that selective solvation of nanoparticles and EPD/EPA complexes may play key roles in stabilization.

Rapid screening with a recombinant antigen (rK39) for diagnosis of visceral leishmaniasis using dipstick

OBJECTIVE

To evaluate the diagnostic value of the recombinant antigen of 39 amino acid repeats encoded by a kinesin-like gene of Leishmania changasi (rK39) in serodiagnosis of visceral leishmaniasis (VL).

METHODS

In Kashi, Xinjiang, 13 VL patients with splenomegaly and bone marrow aspirate culture positive were subjected to dipstick assay. A drop of whole blood or serum from patient was placed at the absorbing pad at the bottom of the dipstick. Flooding of the bottom protein with buffer allows serum proteins to migrate upwards, producing the positive band and Western blot analysis of rK39 subsequently performed with the sera collected.

RESULTS

The end-point titers of anti-rK39 antibodies of these sera were determined by ELISA and found to fall within the range of 10(-2) to 10(-4), which were consistent with the intensity of their reaction with rK39 in dipstick assay. The positive sera could also recognize the specific rK39 band as analyzed by Western blot analysis.

CONCLUSION

The rK39 dipstick assay is more rapid, specific, sensitive and less invasive than the conventional methods of diagnosis for VL in the areas of low endemicity.

Effect of bilateral testicular resection on thymocyte and its microenvironment in aged mice

AIM

To observe the changes in thymocyte and its microenvironment in aged mice after bilateral testicular resection.

METHODS

In male old mice, at the 25th day after testicular resection, the peripheral blood and thymus were collected. Blood and thymus suspension smears were prepared for quantitative histochemistry and immunohistochemistry study under light and electron microscopes.

RESULTS

In testes resected mice the size and the weight of thymus were markedly increased. The demarcation between cortex and medulla was clear. The cortex was thickened and the cell density was increased. The ratio of cortex/medulla stereometry was increased. The total cell count, thymocyte count, the percentage of acid alpha-naphthyl acetate esterase (ANAE) positive thymocytes, nonlymphocytes and the rosette formation of macrophages and thymocytes were all increased. The thymocytes surrounded closely to the light thymic epithelial cells, dendritic cells or macrophages. The lymphocytes, particularly the ANAE positive lymphocytes of peripheral blood were increased.

CONCLUSION

After bilateral testicular resection, the thymus of aged male mice showed morphological regeneration and the thymocytes and its microenvironment appeared to be definitely improved. It is suggested that testicular resection may improve immune function.

A novel cloud-point extraction process for preconcentrating selected polycyclic aromatic hydrocarbons in aqueous solution

A novel but simple cloud-point extraction (CPE) process is developed to preconcentrate the trace of selected polycyclic aromatic hydrocarbons (PAHs) with the use of the readily biodegradable nonionic surfactant Tergitol 15-S-7 as extractant. The concentrations of PAHs, mixtures of naphthalene and phenanthrene as well as pyrene, in the spiked samples were determined with the new CPE process at ambient temperature (23 degrees C) followed by high performance liquid chromatography(HPLC) with fluorescence detection. More than 80% of phenanthrene and pyrene, respectively, and 96% of naphthalene initially present in the aqueous solutions with concentrations near or below their aqueous solubilities were recovered using this new CPE process. Importantly Tergitol 15-S-7 does not give any fluorometric signal to interfere with fluorescence detection of PAHs in the UV range. No special washing step is, thus, required to remove surfactant before HPLC analyses. Different experimental conditions were studied. The optimum conditions for the preconcentration and determination of these selected PAHs at ambient temperature have been established as the following: (1) 3 wt% surfactant; (2) addition of 0.5 M Na2SO4; (3) 10 min for equilibration time; and (4) 3000 rpm for centrifugal speed with duration of 10 min.

[Studies on the chemical constituents from Aquilegia ecalcarata Maxim]

OBJECTIVE

To study the chemical constituents from Aquilegia ecalcarata.

METHOD

Compounds were isolated with silica gel and polyamide chromatography and their structures were determined by spectral analysis and chemical evidence.

RESULT

Five compounds were obtained and identified as beta-sitosterol, isoorientin-7-O-glucoside, isovitexin-4'-O-glucoside, isovitexin-2'-O-rhamnoside, luteolin-7-O-glucoside.

CONCLUSION

All the compounds were isolated from this plant for the first time.

Translation drag coefficient of a self-similar assembly of spheres immersed in an incompressible fluid

On the basis of deterministic fractals and the Rotne-Prager hydrodynamic interaction tensor, we confirm the asymptotic as well as the finite size scaling of the friction coefficient lambda of a self-similar structure. The fractal assembly is made of N spheres with its dimension varying from D < 1 to D = 3. The number of spheres can be as high as N approximately O(10(4)). The asymptotic scaling behavior of the friction coefficient per sphere is lambda approximately N(1/D-1) for D > 1, lambda approximately (lnN)(-1) for D = 1, and lambda approximately N(0) for D < 1. The crossover behavior indicates that while in the regime of D > 1 the hydrodynamic screening effect grows with the size, for D<1 it is limited in a finite range, which decays with decreasing D.

Aquiledine and isoaquiledine, novel flavonoid alkaloids from Aquilegia ecalcarata

Two new flavonoid alkaloids, aquiledine (1) and isoaquiledine (2), were isolated from the whole herb of Aquilegia ecalcarata, and their structures were determined by detailed spectral analysis. Three known flavonoids were also isolated from this extract-apigenin, apigenin-7,4'-dimethyl ether, and luteolin-and have not been reported previously from A. ecalcarata.

Faxen's Laws of a Composite Sphere under Creeping Flow Conditions

Under creeping flow conditions, Faxen's laws are derived for a composite sphere comprising a solid core covered by a permeable layer of arbitrary thickness. The derivations are carried out by applying reciprocal theorem in combination with fluid velocity and pressure distributions in certain simple flow as a comparison field. In this regard, the fluid velocity disturbances caused by a composite sphere subject to a simple shear flow and a rotational flow are solved individually. In the limiting case where the solid core vanishes, the resulting Faxen expressions for the drag force, torque, and stresslet compare very well with the existing Faxen's law for a porous sphere. It is found that when the porous layer is thick enough and its permeability is sufficiently low, the hydrodynamic behavior of a composite sphere can be approximated by that of a porous particle with equal permeability. This can be explained by the fact that the fluid cannot penetrate deeply into a porous layer of low permeability to flow through the pores near the core surface, and thereby the fluid can hardly feel the resistance from the core surface. Copyright 2000 Academic Press.

Hydrodynamic Interactions and Mean Settling Velocity of Porous Particles in a Dilute Suspension

A theoretical investigation is conducted to study hydrodynamic interactions among porous spheres under creeping flow conditions. The particles may differ in size and permeability. Based on the Brinkman equation governing the fluid flow inside the particle, the flow field, and the drag force and torque on the particle are calculated numerically using a boundary collocation method. The results show that the hydrodynamic interaction increases with decreasing permeability. An important feature is that unlike the singular force and torque for two touching identical impermeable spheres undergoing certain motions with planar symmetry, the force and torque always remain finite for the case of two porous spheres. Using the resulting hydrodynamic interactions, the average sedimentation velocity of porous spheres suspended in a bounded fluid is also evaluated to determine the leading order effect of the particle concentration. Because of weaker hydrodynamic interactions among porous spheres, the hindrance coefficient is smaller than that for impermeable particles. When the porous spheres carry charge, the hindrance effect is augmented by increasing the double layer thickness. Copyright 1999 Academic Press.

Electrostatic Interaction and Hindered Diffusion of Ion-Penetrable Spheres in a Slit Pore

Electrostatic interaction and hindered diffusion of ion-penetrable spheres in a slit pore filled with an electrolyte solution are investigated theoretically. The concentration of the particles is assumed sufficiently low so that the interactions between the particles can be neglected. The slit pore comprises two parallel infinite plates, which can be either permeable or impermeable to the electrolyte. The electrostatic interaction energy is obtained analytically by adopting an integral of Green's function and an image method. It is found that for impermeable plates having constant surface charge densities, the electrostatic interaction can be attractive or repulsive for a particle with charge of opposite sign, depending on the relative magnitudes of charge densities and particle location. Similar behavior is predicted for plates with constant surface potential and a particle with charge of like sign. The interaction energy is used to determine the spatial distribution of the particle in the pore and the partition coefficient, and then to calculate the average and apparent diffusivities. The average diffusivity calculated from the average mobility in the pore is always smaller than that in the bulk solution because of greater drag the particle experiences in the presence of the plates. This mean diffusivity is larger than that in the corresponding neutral system for repulsive electrostatic interaction, but becomes smaller for attractive interaction. The apparent diffusivity defined from the flux based on the bulk concentration of the particle depends strongly on the ion concentration, as does the partition coefficient when the double layer is sufficiently thick. Copyright 1998 Academic Press.

Advantages of laparoscopic splenectomy for splenomegaly due to hematologic diseases

Recent advancements in laparoscopic surgery have made laparoscopic splenectomy possible. We retrospectively compared the outcomes of laparoscopic versus open splenectomy in patients with idiopathic thrombocytopenic purpura (ITP) or beta-thalassemia. From July 1993 to July 1997, 52 patients (ITP, 43 cases; beta-thalassemia, 9 cases) underwent either laparoscopic (30 patients, 9 men, 21 women; average age, 36.9 years) or conventional open splenectomy (22 patients, 5 men, 17 women; average age, 34.3 years). The two groups were similar in terms of sex, age, diagnosis, duration of disease, preoperative platelet count, and spleen size. The mean surgical time, estimated amount of blood loss, duration of postoperative recovery, analgesic usage, and complications were compared between the two groups. Laparoscopic splenectomy was successful in 29 (97%) of the 30 patients. The mean surgical time in the laparoscopy group was longer than in the open splenectomy group (190.6 vs 113.9 minutes, p < 0.01). The laparoscopy group had earlier postoperative oral intake (15.2 vs 52.6 hours, p < 0.01), less usage of analgesics (meperidine 50 mg/unit, 1.1 vs 2.8 units, p < 0.01) and a shorter postoperative hospital stay (4.1 vs 6.8 days, p < 0.01). The estimated blood loss, incidence of accessory spleen, surgical complication rate, and recurrence rate of thrombocytopenia were similar in the two groups. Our findings show that laparoscopic splenectomy in patients with ITP or beta-thalassemia is as safe as the open approach. While laparoscopy required a longer surgical time, the recovery period was shorter, analgesic use was less, and physical discomfort was less severe.

Women's health in the People's Republic of China: some challenges of modernization

OBJECTIVE

To identify aspects of the health of Chinese women throughout their lifespan which may paradoxically be threatened by modernization and to suggest relevant interventions through medical practice, education and research to meet these challenges.

DATA SOURCES

Six risk areas were selected as examples: infant sex ratios; tobacco use by girls; respiratory illness plus anemia; psychosocial stress; osteoporosis; and dementia. Articles and other databases, through article citations, and through consultations with Chinese medical professionals.

DATA SELECTION

Studies were selected which described clinical investigations, health care policy, or conditions of women in the People's Republic of China (PRC). Preference (but not exclusivity) was given to articles in internationally available publications, in English, and to authors working in the PRC.

DATA EXTRACTION

Study quality, specific descriptive information concerning population, samples, and outcome measures were evaluated.

DATA SYNTHESIS

Data documenting the present and future significance of these health threats are described, and current and potential interventions to address these problems through medical practice, education and research are outlined.

CONCLUSION

Important issues in women's health are currently recognized in the PRC; problems occur in assigning priorities in the face of a large population and limited resources. The Chinese medical community plays a central role in developing and carrying out interventions to protect and promote women's health.

Self-learning fuzzy neural networks for control of uncertain systems with time delays

We address the problem of control of uncertain systems with time delays. Using the fuzzy logic control and artificial neural network methodologies, we present a self-learning fuzzy neural control scheme for general uncertain processes. In this scheme, a neural network compensator is designed instead of the classical Smith predictor for attenuating the adverse effects of time delays of the uncertain systems. The scheme has been used in control of welding pool dynamics of the arc welding process, and the experiment results show the control scheme available.

International access to the Chinese medical literature through MEDLINE

This article reviews, for authors publishing in the Chinese literature, the characteristics of MEDLINE users, the format of MEDLINE citations and the main retrieval strategies used with the system. References were retrieved and data collected through MEDLINE searches of the database 1988-June 1992. Thirty-six indexed journals from the People's Republic of China (PRC) were analyzed. The items of a MEDLINE citation are described. Titles of Chinese journals are listed in English as well as Chinese in the annual "List of Serials Indexed" of Index Medicus. Articles from journals in the PRC are indexed at the China MEDLARS Center, Beijing, PRC. For the 36 journals analyzed, 12,530 citations appeared in MEDLINE during the search period. Basic search strategies are described. Users doing author searches may have difficulties with common Chinese surnames, especially if only one given name initial is used. Journal searches of specialty journals, as well as address field searches for publications from a particular institution, may be helpful to scientists planning a visit to China. Effective use of MEDLINE has become an opportunity and responsibility for scientists and physicians over the world. Suggestions for preparation of English titles and abstracts to assure optimal information transfer and retrieval efficiency are: think about your audience; do not waste words; include key features in the title; be consistent with names and affiliations; use MeSH terms; include important non-MeSH terms in text; use structured abstracts; and obtain MEDLINE printouts of your own citations.

[Diagnostic value of serum CA 19-9 determination in digestive tract cancer]

Serum carbohydrate antigen CA 19-9 level was measured by radioimmunoassay in 55 patients with malignant digestive disease (14 esophageal cancers, 11 gastric cancers, 5 colorectal cancers, 14 primary liver cancers and 11 pancreatic cancers). The mean value of serum CA 19-9 levels was 22.11 +/- 24.79 u/ml in esophageal cancer, 99.91 +/- 100.12 u/ml in gastric cancer, 64.5 +/- 53.43 u/ml in colorectal carcinoma, 47.81 +/- 68.62 u/ml in primary hepatic cancer and 459.55 +/- 696.76 u/ml in pancreatic cancer (CA 19-9 greater than 37 mu/ml as positive). There were significant differences (P less than 0.05) between the mean serum CA 19-9 levels of pancreatic cancer and esophageal cancer, primary hepatic cancer. An increased CA 19-9 synthesis and excretion by tumor cells or increased pressure on pancreatic duct by the tumor may cause the elevation of serum CA 19-9 level in cancer patients. The authors conclude that CA19-9 is a valuable tumor marker in the diagnosis of pancreatic cancer and, probably, other gastrointestinal tumors.

Use of serum and vaccine in combination for prophylaxis following exposure to rabies

Persons seriously wounded by rabid animals in China were administered postexposure rabies treatment with serum and vaccine. Some of these exposures were similar to those described in an attack by a rabid wolf in Iran in 1954, in which some persons developed rabies. Postexposure treatment consisted of the administration of primary hamster kidney cell rabies vaccine and purified equine antirabies serum. Persons with severe wounds from the bites of rabid animals survived without sequelae when the serum and vaccine were administered together within 3 days of the bite, and persons with superficial exposures survived after treatment with vaccine alone. Serum neutralizing antibodies were present 1 year after the patients had received a full course of treatment. Some persons with severe wounds who had not received antiserum and vaccine died of rabies.

[Clinical features and treatment results in 88 children with malignant lymphoma]

Clinical features and treatment results of 88 children with malignant lymphoma as treated in our hospital from Jan. 1973 to May 1984 are reported. These patients were 39 Hodgkin's disease, 41 non-Hodgkin's lymphoma and 8 unclassified. Peak age ranged from 6 to 10 years. 12 patients were in stage I, 35 in stage II, 7 in stage III and 34 in stage IV. In this series, misdiagnosis rate was 90%. The treatment methods included radiotherapy plus chemotherapy or surgery and chemotherapy alone. The complete remission rate (CR) was 40.7% and partial remission (PR) 42.8%. The radiotherapy plus chemotherapy or surgery gave the highest CR (60.8%). The overall 3 and 5 year survival rates were 51.4% and 46%. In stages I and II, 5 year survival rate was 67.6% and in stages III and IV, it was 15%. The 3 and 5 year survival rates in CR were 87% and 75%, that in PR were 18.2% and 12.1%. Those of Hodgkin's disease were higher than that of non-Hodgkin's lymphoma (92.5% and 75% versus 25.8% and 19.3%). The 5 year survival of radiotherapy plus chemotherapy or surgery was the highest. The patients who received a tumor dose of 4,100-5,200 rad had the best prognosis (81% for 5 year survival rate). It is indicated that the stage, pathologic type, age, treatment method, CR and radiation dose are the prognostic factors in children with malignant lymphoma.