Analysis of the human and ape foot during bipedal standing with implications for the evolution of the foot

The ratio of the power arm (the distance from the heel to the talocrural joint) to the load arm (that from the talocrural joint to the distal head of the metatarsals), or RPL, differs markedly between the human and ape foot. The arches are relatively higher in the human foot in comparison with those in apes. This study evaluates the effect of these two differences on biomechanical effectiveness during bipedal standing, estimating the forces acting across the talocrural and tarsometatarsal joints, and attempts to identify which type of foot is optimal for bipedal standing. A simple model of the foot musculoskeletal system was built to represent the geometric and force relationships in the foot during bipedal standing, and measurements for a variety of human and ape feet applied. The results show that: (1) an RPL of around 40% (as is the case in the human foot) minimizes required muscle force at the talocrural joint; (2) the presence of an high arch in the human foot reduces forces in the plantar musculature and aponeurosis; and (3) the human foot has a lower total of force in joints and muscles than do the ape feet. These results indicate that the proportions of the human foot, and the height of the medial arch are indeed better optimized for bipedal standing than those of apes, further suggesting that their current state is to some extent the product of positive selection for enhanced bipedal standing during the evolution of the foot.

Covalent immobilization of chitosan and heparin on PLGA surface

Chitosan and heparin were covalently immobilized onto a poly(lactic acid-co-glycolic acid) (PLGA) surface using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC), N-hydroxysuccinimide (NHS) in a 2-morpholinoethane sulfonic acid (MES) buffer system. The properties of the modified PLGA surface and the control were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The water contact angle of the modified film was greatly decreased and the element content on the surface of the films changed correspondingly. Platelet adhesion assay showed that blood compatibility of the chitosan/heparin modified film was improved while hepatocyte culture indicated that the cell compatibility of the modified film was enhanced.

Stresses Exerted in the Hindlimb Muscles of Common Chimpanzees (Pan troglodytes) during Bipedal Locomotion

Recent studies have indicated that chimpanzee bipedality is mechanically inefficient and dynamically unlike that of humans, thus undermining the chimpanzee analogy for mechanical aspects of the early evolution of hominid bipedalism. This paper continues this theme by measuring the forces and stresses engendered by the muscles during bipedal locomotion, for an untrained chimpanzee and for data from chimpanzees which have been encouraged to walk bipedally, presented in the literature. Peak stresses in the triceps surae were lower for the untrained chimpanzee than for the trained subjects because during the late stance phase, when peak ankle moments occur, the centre of pressure of the ground reaction force on the foot of the untrained chimpanzee stayed close to the ankle joint. In contrast, for the trained subjects it moved closer to the toes, as in human bipedalism. Quadriceps and hip extensor stresses are approximately 30% larger for the untrained chimpanzee than for the trained subjects, because the trained chimpanzees walked with a more erect posture. These results may reflect the way in which muscles can develop in response to training, since research on humans has shown that muscle physiological cross-sectional area increases as a result of exercise, resulting in smaller stresses for a given muscle force. During a slow walk, untrained chimpanzees were found to exert far greater muscle stresses than humans do when running at moderate speed, particularly in the muscles that extend the hip, because of the bent-hip, bent-knee posture.

A study of cytokeratin profiles in localized cutaneous amyloids

The major component of localized cutaneous amyloids may be derived from cytokeratin (CK). However, the CK profiles of primary cutaneous amyloidosis (PCA) and secondary cutaneous amyloidosis (SCA) remain obscure. Paraffin-embedded sections of skin tissue from 64 patients with PCA, 111 with SCA and 3 with systemic amyloidosis were analyzed immunohistochemically using 12 different polyclonal or monoclonal anti-CK antibodies (34betaE12, MNF116, LP34, AE1/AE3, anti-CK1, CK5, CK6, CK7, CK10, CK14, CK16 and CK17). In addition, frozen skin tissues from 12 patients with PCA were analyzed for comparison with the paraffin-embedded tissue. In all 64 PCA paraffin sections, the amyloid deposits were immunopositive for anti-CK5 antibody and 34betaE12. In all 12 frozen sections of PCA, the amyloid deposits were immunopositive for anti-CK5 antibody, 34betaE12, MNF116 and LP34, and seven (58.3%), three (25%) and one (8.3%) were immunopositive for anti-CK1, CK14, and CK10 antibodies, respectively. In all SCA sections, the amyloid deposits were immunopositive for CK5 and 34betaE12. In addition, MNF116 immunolabeled amyloids of all sections from patients with basal cell carcinoma and trichoepithelioma, and MNF116 and LP34 immunolabeled amyloids of sections from patients with porokeratosis. Our results indicate that CK5 is the major CK present in the amyloid deposits of PCA and SCA, and "amyloid-K" is mainly derived from basal keratinocytes.

Using improved neural network model to analyze RSP, NOx and NO2 levels in urban air in Mong Kok, Hong Kong

As the health impact of air pollutants existing in ambient addresses much attention in recent years, forecasting of air pollutant parameters becomes an important and popular topic in environmental science. Airborne pollution is a serious, and will be a major problem in Hong Kong within the next few years. In Hong Kong, Respirable Suspended Particulate (RSP) and Nitrogen Oxides NOx and NO2 are major air pollutants due to the dominant diesel fuel usage by public transportation and heavy vehicles. Hence, the investigation and prediction of the influence and the tendency of these pollutants are of significance to public and the city image. The multi-layer perceptron (MLP) neural network is regarded as a reliable and cost-effective method to achieve such tasks. The works presented here involve developing an improved neural network model, which combines the principal component analysis (PCA) technique and the radial basis function (RBF) network, and forecasting the pollutant levels and tendencies based in the recorded data. In the study, the PCA is firstly used to reduce and orthogonalize the original input variables (data), these treated variables are then used as new input vectors in RBF neural network model established for forecasting the pollutant tendencies. Comparing with the general neural network models, the proposed model possesses simpler network architecture, faster training speed, and more satisfactory predicting performance. This improved model is evaluated by using hourly time series of RSP, NOx and NO2 concentrations collected at Mong Kok Roadside Gaseous Monitory Station in Hong Kong during the year 2000. By comparing the predicted RSP. NOx and NO2 concentrations with the actual data of these pollutants recorded at the monitory station, the effectiveness of the proposed model has been proven. Therefore, in authors' opinion, the model presented in the paper is a potential tool in forecasting air quality parameters and has advantages over the traditional neural network methods.

Size and power required for motion with implication for the evolution of early hominids

The fossil record of early hominids (early human ancestors) suggests that their stature and weight had a tendency to increase, but their robusticity (the proportion of radius to length) to decrease. Using a simple musculo-skeletal model, this paper explores possible relationships between size, power required for motion (PRM) and cycle-time, deriving relationships which indicate that PRM per unit of mass and velocity is proportional to robusticity, but inversely proportional to stature. The results derived appear to be in general agreement with published data from physiological experiments. If the material properties of early hominids were similar to those of modern humans and the achievement of minimum PRM was the selective criterion, human stature might tend to increase slightly in human evolution (and, if selective pressures are not removed, might do so in the future but at lower rate). If mobility and stability under loading are the selective criteria, however, human size should not substantially increase in the future.

Crosslinked collagen/chitosan matrix for artificial livers

Matrices composed of collagen and chitosan may create an appropriate environment for the regeneration of livers. In this study, we have prepared, characterized and evaluated a new collagen/chitosan matrix (CCM). The CCM was made by using crosslinking agent 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) in N-hydroxysuccinimide (NHS) and a 2-morpholinoethane sulfonic acid (MES) buffer system. The chemical characteristics were evaluated by Fourier-transformed infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The mechanical strength was measured by tensile tests. The platelet deposition and hepatocyte culture experiments show that CCM has excellent blood and cell compatibility. The results suggest that the CCM is a promising candidate matrix for implantable bioartificial livers.

SPR1 gene near HLA-C is unlikely to be a psoriasis susceptibility gene

Although genetics analyses have identified the HLA-Cw6 allele to be the major risk allele for psoriasis vulgaris (PV) in many racial groups, it has been proposed that other putative genes near the HLA-C locus are involved in PV susceptibility and that the association of Cw6 is a result of linkage disequilibrium. The SPR1 gene, a predicted gene located 128 kb telomeric to the HLA-C locus, is considered to be one potential candidate gene of PV. Until now, no association study of the SPR1 gene has been conducted on psoriasis patients. We investigated the SPR1 gene for disease association by direct sequencing of the SPR1 gene in 116 Chinese patients with PV and 116 normal subjects. Genotyping for HLA-Cw6 was also carried out using polymerase chain reaction/restriction fragment length polymorphism. Significant increase of the HLA-Cw6 allele was found in psoriasis patients (32.8% vs. 13.8%, P = 0.001). We found that the SPR1 gene is a highly polymorphic gene containing 13 single nucleotide polymorphisms (SNPs), two of which have not been previously reported, and four SNPs cause amino acid change. No significantly different allelic distribution of 13 SPR1 SNPs could be found between the patients with PV and controls after correction for multiple testing. If the frequencies of SPR1 SNPs were compared between the early onset psoriatics and control subjects, early onset patients were more likely to have G allele at position 988 (60% vs. 35.3%, P = 0.001). However, the significance disappeared upon stratification for the Cw6 status. Haplotype-based association analysis showed two susceptibility haplotypes (types 8 and 19) in early onset psoriasis patients. Nonetheless, the significance also disappeared after stratification of the Cw6 status. Our results suggest that HLA-Cw6 remains the major risk allele in Chinese psoriatics, and that the SPR1 gene might not play an important role in the causation of PV.

Energy transformation during erect and 'bent-hip, bent-knee' walking by humans with implications for the evolution of bipedalism

We have previously reported that predictive dynamic modeling suggests that the 'bent-hip, bent-knee' gait, which some attribute to Australopithecus afarensis AL-288-1, would have been much more expensive in mechanical terms for this hominid than an upright gait. Normal walking by modern adult humans owes much of its efficiency to conservation of energy by transformation between its potential and kinetic states. These findings suggest the question if, and to what extent, energy transformation exists in 'bent-hip, bent-knee' gait. This study calculates energy transformation in humans walking upright, at three different speeds, and walking 'bent-hip, bent-knee'. Kinematic data were gathered from video sequences and kinetic (ground reaction force) data from synchronous forceplate measurement. Applying Newtonian mechanics to our experimental data, the fluctuations of kinetic and potential energy in the body centre of mass were obtained and the effects of energy transformation evaluated and compared. In erect walking the fluctuations of two forms of energy are indeed largely out-of-phase, so that energy transformation occurs and total energy is conserved. In 'bent-hip, bent-knee' walking, however, the fluctuations of the kinetic and potential energy are much more in-phase, so that energy transformation occurs to a much lesser extent. Among all modes of walking the highest energy recovery is obtained in subjectively 'comfortable' walking, the next highest in subjectively 'fast' or 'slow' walking, and the least lowest in 'bent-hip, bent-knee' walking. The results imply that if 'bent-hip, bent-knee' gait was indeed habitually practiced by early bipedal hominids, a very substantial (and in our view as yet unidentified) selective advantage would have had to accrue, to offset the selective disadvantages of 'bent-hip, bent-knee' gait in terms of energy transformation.

A study of candidate genes for psoriasis near HLA-C in Chinese patients with psoriasis

BACKGROUND

Genetic analyses have identified the HLA-Cw6 allele as the major risk allele for psoriasis in many racial groups. However, by serological typing, HLA-Cw6 is not considered a risk factor in Chinese psoriatics. There are several susceptibility genes for psoriasis residing in chromosome 6p near the HLA-C locus, including the corneodesmosin (CDSN) gene, the octamer transcription factor-3 (POU5F1) gene, the major histocompatibility complex class I chain-related gene A (MICA), and the gene for tumour necrosis factor (TNF)-alpha. However, the information about their role in psoriasis in Chinese patients is limited.

OBJECTIVES

We aimed to determine whether Cw6 and the genetic polymorphism of the CDSN gene, POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region were associated with an increased risk of psoriasis in Chinese patients.

METHODS

We conducted a case-control association study in 105 Chinese patients with psoriasis vulgaris and 160 control subjects of similar ages. Genotypes of Cw6, the CDSN gene, the POU5F1 gene, and the gene for the TNF-alpha promoter region were determined by polymerase chain reaction (PCR) followed by restriction enzyme digestion. Genotyping of MICA was determined by PCR combined with fluorescent-based automated fragment detection technology. Results The allele frequencies showed no differences between patients and controls for the POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region. The frequency of the HLA-Cw6 allele in the psoriasis group was significantly higher than that in the control group (18.6% vs. 6.56%, P < 0.00005). For the CDSN gene, patients were more likely to have C allele at position +619 (P = 0.006) and C allele at position +1243 (P = 0.007), but the significance disappeared after correction for multiple testing (Pc > 0.05).

CONCLUSIONS

HLA-Cw6 remains the most significant susceptibility gene in Chinese patients with psoriasis. However, the role of the CDSN gene in the pathogenesis of psoriasis deserves further scrutiny.

Optimum ratio of upper to lower limb lengths in hand-carrying of a load under the assumption of frequency coordination

The ratio of the upper to lower limb lengths [or the intermembral index (IMI)] in the earliest human ancestors is closer to that of the living chimpanzees than to our own, although the former show undoubted adaptations to bipedality. What biomechanical factors could then have led to the phenomenon of genus Homo? This paper proposes and evaluates a relationship between IMI and hand-carrying. Assuming that coordination of limb swing frequencies of the upper and lower limbs would be the subject of positive selection, a mathematical expression was derived and can in part explain the changes in IMI. We found that AL-288-1 [3.6 million years old (MY)], the most complete skeleton of the early hominid Australopithecus afarensis, could only have carried loads equivalent to 15-50% of the upper limb weight while maintaining swing symmetry, but KNM WT-15000, Homo ergaster (1.8MY) and modern humans could both carry loads 3 times heavier than the upper limb while maintaining swing symmetry. The carrying ability of chimpanzees would be inferior to that of AL-288-1. The IMI of modern humans, at 68-70, is the smallest, and is optimal for hand-carrying under our criteria. Under reduced selection pressure for hand-carrying, but unreduced selection for mechanical effectiveness, we might expect humans to evolve a longer upper limb, to improve swing symmetry when unloaded.

Isolation, culture, and characterization of endocrine cells from 6-month-old porcine pancreas

Porcine endocrine cells were isolated from pancreas of 6-month-old pigs by two-step enzymatic digestion procedures. They were separated by the density gradient (isopycnic) centrifugation method using Histopaque-1077. Isolated cells were cultured and divided into two groups: suspension cells and adhesion cells. Suspension cells maintained their cell numbers on and after 7 days in culture. Approximately 1 x 10(7) cells were obtained from single pancreas of a 6-month-old pig. The cultured suspension cells took up dithizone (DTZ) staining 14 days after isolation in culture and indicated the presence of beta-cells. In in vitro study, the suspension cells were capable of secreting insulin into the culture medium. The suspension cells were tested for insulin and glucagon staining by Western blot analysis. These results indicated the maintenance of endocrine cell function after isolation. However, cultured adhesion cells failed to maintain their function during culture. In in vivo study, the suspension cells were transplanted into diabetes-induced nude mice. Reduction in blood glucose level was obtained after transplantation. Intraperitoneal glucose tolerance test (IPGTT) results showed a normal pattern of blood glucose clearance. After 1 week, the transplanted endocrine cells were detected with anti-insulin antibody by immunostaining and it showed the presence of viable beta-cells under the renal capsule of nude mice. Collectively, our results suggest that isolated and cultured suspension porcine endocrine cells maintained their endocrine function. These endocrine cells can be used as isolated islets for further study, including transplantation experiments.

Synthesis and post-translational processing of surfactant protein C

Traditional thinking about surfactant proteins has centered around their effects on the biophysical properties of surfactant phospholipids. Accumulated data now suggests that the four major surfactant proteins (SPs) are a biochemically and functionally diverse group of mammalian peptides that have function beyond modification of alveolar surface tension. Alveolar SP-C (SP-C3.7, Mr 21,000) is 35 amino acid peptide isolated from lung surfactant that is synthesized and processed from a 191-197 amino acid precursor (proSP-C21). Although its solubility in organic solvents and avidity for lipid membranes impart properties important for its biophysical activity, SP-C represents a structurally and functionally challenging protein for the alveolar type II cell that must synthesize and traffic the peptide through the regulated secretory pathway. Despite technical and analytical difficulties imposed by its unique structure, our current understanding of SP-C biosynthesis has evolved over the past 10 years. Recent data now require us to consider proSP-C21 as a hybrid molecule incorporating structural and functional features both of bitopic integral membrane proteins as well us more classically recognized propeptide hormones. Our article highlights major developments related to characterization of molecular and cellular mechanisms underlying expression, post-translational processing, and targeting of proSP-C21 that result in production of secreted SP-C3.7.

[Investigation on the excited state dynamics properties of hemicyanine molecules]

In this paper, the excited state dynamics properties of hemicynine were investigated by using time-resolved fluorescence and 3D fluorescence spectra techniques. The interaction of hemicyanine molecules caused formation of H-aggregates and a blue shift of the 3D fluorescence spectra in interleaving hemicyanine/arachidic acid multilayers. The peak of fluorescence was a red shift along with the time decay. The lifetime of the LB fluorescence was much shorter and the difference of beginning luminescence was less than that of the hemicyanine solution due to the stronger intermolecule interactions in the aggregates.

A novel tetrameric venom protein, agglucetin from Agkistrodon acutus, acts as a glycoprotein Ib agonist

A novel platelet agglutination inducer, agglucetin, was purified from the Formosan Agkistrodon acutus snake venom. It migrated as a single band with an apparent molecular mass of 58.8 kDa and two distinct bands of 16.2/14.5 kDa under non-reducing and reducing conditions by SDS-PAGE, respectively. Further confirmed by FPLC, electrospray ionization mass spectrometry and 2D-PAGE, native agglucetin exists as a tetramer composed of disulfide-linked alpha1, alpha2, beta1 and beta2 subunits. Partial N-terminal sequence of agglucetin subunit showed a high degree of homology to those of C-type lectin-like glycoprotein (GP) Ib binding proteins. Functional studies showed that agglucetin. in the absence of von Willebrand factor (vWF), dose-dependently induced platelet agglutination and caused a negligible elevation of intracellular Ca+2 mobilization and thromboxane B, formation in human platelet suspensions. Anti-GP Ib monoclonal antibodies (mAbs), AP1 or LJ-Ib1, specifically inhibited agglucetin-induced platelet agglutination in a dose-dependent manner. However, EDTA, arietin (a long chain RGD-containing disintegrin), 7E3 (an anti-GP IIb/IIIa mAb), heparin, hirudin, PGE1, or indomethacin exhibited no inhibitory effect on agglucetin-induced platelet agglutination. Furthermore, flow cytometric analysis revealed that FITC-agglucetin dose-dependently bound to human formalin-fixed platelets in a saturable manner, and its binding was specifically blocked by anti-GP Ib mAb. It is concluded that agglucetin, acts specifically on an epitope of platelet membrane GP Ib overlapping with that of API, causing platelet agglutination in a Ca+2- and GP IIb/IIIa-independent manner.

A study of apolipoproteins E and A-I in cutaneous amyloids

BACKGROUND

Apolipoprotein E (apoE) is present in a variety of biochemically different amyloid deposits, including Alzheimer's disease, systemic amyloidosis and primary cutaneous amyloidosis (PCA). Among the three closely related alleleic forms of apoE, the epsilon4 allele is linked to Alzheimer's disease. Apolipoprotein A-I (apoA-I), another apolipoprotein, is also found in senile plaques of Alzheimer's disease and in amyloid of aortic atherosclerotic plaques. Furthermore, apoA-I has recently been found to be associated with hereditary cutaneous and cardiac amyloidosis.

OBJECTIVES

To determine whether the apoE epsilon4 allele is associated with increased risk of PCA and whether apoE and apoA-I are present in PCA and common secondary cutaneous amyloidosis (SCA) (i.e. basal cell carcinoma, Bowen's disease and seborrhoeic keratosis).

METHODS

We examined the apoE genotype in 57 Chinese patients with PCA and 58 normal healthy control subjects of similar age. In addition, immunohistochemical staining was performed to determine the localization of apoE and apoA-I in skin tissues from 15 patients with SCA and 15 with PCA.

RESULTS

The frequency of the epsilon4 allele in the PCA group was not significantly higher than that in the control group (8.8% vs. 6.9%, P > 0.05). ApoE was present in amyloid deposits in both PCA and SCA, but apoA-I was not detected in these cutaneous amyloid deposits.

CONCLUSIONS

ApoE is also a component of amyloid deposits in SCA. Although the genetic susceptibility of certain apoE isoforms may not be a crucial factor in the development of PCA and, although apoA-I is not associated with amyloid deposits of PCA and SCA, the role of apolipoproteins in amyloidogenesis deserves further scrutiny.

[Treatment of cervical disc herniation with percutaneous arthroscopic microdisectomy]

OBJECTIVE

To study the indications and efficacy of percutaneous cervical arthroscopic microdiscectomy (PCAD).

METHODS

Twenty eight patients with cervical discs herniation or disorders received endoscopic spine surgery, 37 intervertebral cervical discs underwent partial nuclectomy or total nucleotomy; the efficacy and complication were evaluated in three months after operation. RELUT: Good/excellent results were obtained in 23/28(82.2%) cases according to MacNab criteria; no serious complication was found; the cervical stability did not decrease in most cases.

CONCLUSION

PCAD is a safe, accuracy and rational method in diagnosing and treating herniated cervical disc and discogenic disorders.

[Study on reversed-phase high performance liquid chromatography separation condition and determination method of organic acids]

The pH values of the mobile phase which affect the chromatographic behavior of organic acids in RP-HPLC have been studied. It was considered that the problem of organic acids on an RP-HPLC column was dissociation. The equation for finding the optimum pH of mobile phase was pHlimit of colunm < or = pH < or = pKa -2. In addition the effects of contents of methanol and acetonitrile in mobile phase were studied. By using the formula the mobile phases used for the analysis of organic monobasic acids--formic, acetic, propionic and butyric acid and of organic dibasic acids--propane diacid, butane diacid, pentane diacid and hexane diacid were proposed. For the analysis of the monobasic acids, the wavelength of UV-detector was set at 210 nm and the mobile phase was a mixture of phosphate buffer solution(15 mmol/L, pH 2.1)-methanol(85:15, V/V) and at a rate of 1.5 mL/min and the column was Diamond C18, 150 mm x 4.6 mm i.d.. The average coefficient of correlation was 0.9997 and RSD was less than 0.90%. The mobile phase for organic dibasic acids was a mixture of phosphate buffer solution (20 mmol/L, pH 2.1)-methanol(75:25, V/V). The other conditions were the same as for organic monobasic acids. The average coefficient of correlation was 0.9998 and RSD was less than 0.70%.

Post-translational processing of surfactant protein-C proprotein: targeting motifs in the NH(2)-terminal flanking domain are cleaved in late compartments

Rat surfactant protein (SP)-C is a 3.7-kD hydrophobic lung-specific protein generated from proteolytic processing of a 21-kD propeptide (SP-C(21)). We have demonstrated that initial post-translational processing of SP-C(21) involves two cleavages of the COOH-terminus (Beers and colleagues, J. Biol. Chem. 1994;269:20,318--20,328). The goal of the current study was to define processing and function of the NH(2)-terminal flanking domain. Epitope-specific antisera directed against spatially distinct regions of the NH(2) terminus, NPROSP-C(2-9) (epitope = D(2)-L(9)) and NPROSP-C(11-23) (= E(11)-Q(23)) were produced. By Western blotting, both antisera identified SP-C(21) in microsomes. A 6-kD form (SP-C(6)), enriched in lamellar bodies (LBs), was detected only by NPROSP-C(11-23) and not extractable with NaCO(3) treatment. Immunogold staining of ultrathin lung sections with NPROSP-C(11-23) identified proSP-C in both multivesicular bodies (mvb) and LBs whereas NPROSP-C(2-9) labeled only mvb. (35)S-pulse chase analysis demonstrated synthesis of SP-C(21) and three intermediate forms (SP-C(16), SP-C(7), and SP-C(6)). Complete processing involved four separate cleavages with a precursor- product relationship between the low molecular weight forms SP-C(7) and SP-C(6). Fluorescence microscopy of A549 cells expressing fusion proteins of enhanced green fluorescent protein (EGFP) and proSP-C NH(2)-terminal deletion mutants showed targeting of EGFP/SP-C(1-194) and EGFP/SP-C(10-194) to early endosomal antigen-1-negative, CD-63-positive cytoplasmic vesicles whereas EGFP/SP-C(19-194), EGFP/SP-C(Delta 10-18), and EGFP/SP-C(24-194) were restricted to the endoplasmic reticulum (ER). We conclude that synthetic processing includes a previously unrecognized cleavage of the proximal NH(2) terminus (M(1)-L(9)), which occurs after removal of COOH-flanking domains (H(59)-I(194)) but before packaging in LBs, and that the region M(10)-T(18) is required for targeting of proSP-C to post-ER vesicular compartments in the biosynthetic pathway.

[Effects of ginkgolide B on arachidonic acid metabolizing enzymes and level of intracellular calcium in rat polymorphonuclear leukocytes]

AIM

To investigate the effects of ginkgolide B on arachidonic acid (AA) metabolizing enzymes and the level of intracellular calcium in rat polymorphonuclear leukocytes.

METHODS

Intracellular free calcium was quantitated by Fura-2 fluorescence technique. Phospholipase A2 (PLA2) activity was determined by incorporating 3H-arachidonic acid in leukocytes. 5-Lipoxygenase (5-LO) activity was evaluated by RP-HPLC.

RESULTS

In comparison with control, ginkgolide B at final concentration of 0.1-10 mumol.L-1 inhibited A23187 induced AA release by 10.9%-22.2%; at final concentration of 0.1-50 mumol.L-1, ginkgolide B inhibited LTB4 and 5-HETE synthesis stimulated by PAF by 29.4%-88.8% and 26.2%-89.3% respectively. At the final concentration of 0.1-100 mumol.L-1, ginkgolide B decreased the rise of intracellular calcium level induced by pletelet activating factor (PAF) and N-formyl-methionine-leucine-phenglalanine (fMLP) by 13.9%-51.4% and 2.2%-36.6%, respectively.

CONCLUSION

Ginkgolide B was found to significantly inhibit PLA2 and 5-LO activities, as well as the increase of the intracellular calcium induced by PAF.

Clinical and histopathological characteristics of primary cutaneous amyloidosis in 794 Chinese patients

BACKGROUND

Primary cutaneous amyloidosis (PCA) is not uncommon in Chinese patients. The disease is usually persistent and quite pruritic. Patients who suffer from this disease usually respond poorly to conventional treatment. We thus reviewed our cases of PCA to discuss the clinical and pathological characteristics.

METHODS

Seven hundred and ninety-four Chinese patients with PCA who visited the Department of Dermatology, Taipei Veterans General Hospital during the last 26-year period were examined and retrospectively studied. The diagnosis in these patients was confirmed by histopathological studies.

RESULTS

Among the many types of PCA, lichen amyloidosis was the most common clinical variant (67%). Pure cases of macular amyloidosis accounted only 8% and were often associated with lichenoid lesions to form biphasic amyloidosis, which was composed of 25% in our series. Other rare types of PCA, such as nodular, anosacral, and vitiliginous amyloidosis, always required a careful differential diagnosis clinically from other similar skin disorders. In addition, 56 familial cases were found. Histopathologically, the most common epidermal findings of PCA were hyperkeratosis, irregular acanthosis with thinning of rete ridges, and expansion of dermal papillae by amyloid deposition. Special histochemical stains were helpful for confirming the existence of amyloid.

CONCLUSIONS

Our study represents the largest number of cases of PCA collected to date. Based on the data, most cases are sporadic, except 56 familial cases which may suggest the possible genetic role. Rare types of PCA, such as anosacral and vitiliginous amyloidosis which need special attention, compose a diagnostic challenge to a dermatologist. Histochemically, H&E stain can give a primary clue for the diagnosis of amyloidosis and crystal violet stain is a very simple and sensitive method to detect the existence of amyloid.

Biosynthesis of surfactant protein C: characterization of aggresome formation by EGFP chimeras containing propeptide mutants lacking conserved cysteine residues

Surfactant protein C (SP-C) is a lung-specific secreted protein, which is synthesized as a 21-kDa propeptide (SP-C(21)) and then proteolytically processed as a bitopic transmembrane protein in subcellular compartments distal to the medial Golgi to produce a 3.7 kDa mature form. We have shown that initial processing of SP-C(21) involves two endoproteolytic cleavages of the C terminus and that truncation of nine amino acids from the C-flanking peptide resulted in retention of mutant protein in proximal compartments. Because these truncations involved removal of a conserved cysteine residue (Cys(186)), we hypothesized that intralumenal disulfide-mediated folding of the C terminus of SP-C(21) is required for intracellular trafficking. To test this, cDNA constructs encoding heterologous fusion proteins consisting of enhanced green fluorescent protein (EGFP) attached to the N terminus of wild-type rat proSP-C (EGFP/SP-C(1–194)), C-terminally deleted proSP-C (EGFP/SP-C(1–185); EGFP/SP-C(1–191)) or point mutations of conserved cysteine residues (EGFP/SP-C(C122G); EGFP/SP-C(C186G); or EGFP/SP-C(C122/186G)) were transfected into A549 cells. Fluorescence microscopy revealed that transfected EGFP/SP-C(1–194) and EGFP/SP-C(1–191)were expressed in a punctate pattern within CD-63 positive, EEA-1 negative cytoplasmic vesicles. In contrast, EGFP/SP-C(1–185), EGFP/SP-C(C122G), EGFP/SP-C(C186G) and EGFP/SP-C(C122/186G) were expressed but retained in a juxtanuclear compartment that stained for ubiquitin and that contained (γ)-tubulin and vimentin, consistent with expression in aggresomes. Treatment of cells transfected with mutant proSP-C with the proteasome inhibitor lactacysteine enhanced aggresome formation, which could be blocked by coincubation with nocodazole. Western blots using a GFP antibody detected a single form in lysates of cells transfected with EGFP/SP-C cysteine mutants, without evidence of smaller degradation fragments. We conclude that residues Cys(122) and Cys(186) of proSP-C are required for proper post-translational trafficking. Mutation or deletion of one or both of these residues results in misfolding with mistargeting of unprocessed mutant protein, leading to formation of stable aggregates within aggresomes.

[Effects of musk glucoprotein on the function of rat polymorphonuclear leukocytes activated by IL-8 in vitro]

OBJECTIVE

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on some functions of rat polymorphonuclear leukocytes activated by IL-8 in vitro.

METHOD

An in vitro incubation system was used. Superoxide anion production was determined by cytochrome C reduction. beta-glucuronidase and lysozyme release was quantitated by enzyme reactions in which phenolph-thaleinglucuronic acid and Micrococcus Lysodeikticus were as the substrates, respectively.

RESULTS

In comparison with control, musk-1 at concentration 1-100 micrograms.ml-1 can increase superoxide anion production by 91.7%-291%, and decrease beta-glucuronidase and lysozyme release by 2.2%-58.1% and 3.9%-39.8%, respectively.

CONCLUSION

Inhibition of lysosomel enzyme release might be considered as one of mechanisms of antiinflammatory action of musk.

[Effects of musk glucoprotein on PAF production and cytosolic Ca2+ level in rat polymorphonuclear leukocytes in vitro]

OBJECTIVE

To investigate the effects of Musk glucoprotein on platelet activating factor (PAF) production and the concentration of cytosolic free Ca2+ in polymorphonuclear leukocytes of rat.

METHODS

An in vitro incubation system was used, production of PAF and activity of acetyl transferase were measured by isotope incorporation, the concentration of cytosolic free Ca2+ was quantitated using the fluorescent Ca2+ indicator Fura-2.

RESULTS

Musk-1 at concentration of 1-100 micrograms.ml-1 can significantly inhibit production of PAF, activity of acetyl transferase and the increase of cytosolic Ca2+ concentration in polymorphonuclear leukocytes of rat.

CONCLUSION

Part of mechanisms underlying antiinflammatory action of Musk-1 is through inhibiting the synthesis of PAF and the increase of cytosolic Ca2+ level.

Anosacral cutaneous amyloidosis: a study of 10 Chinese cases

BACKGROUND

Primary cutaneous amyloidoses are rare in Western countries, but are relatively common in Taiwan. Anosacral cutaneous amyloidosis is a rare type of primary cutaneous amyloidoses, first reported in Japanese patients.

PATIENTS/METHODS

In the present study, we investigated the age of onset, sites of involvement, associated systemic diseases, and histopathological findings in 10 cases of anosacral cutaneous amyloidosis seen during the past 27 years.

RESULTS

In previous reports the aetiology of anosacral cutaneous amyloidosis was thought to be a senile change, but half of our patients developed the disease before the age of 60 years. Based on our histopathological findings, apoptosis may be the initial event causing amyloid deposition, although the precise mechanism causing apoptosis needs further investigation. Three patients were found to have diabetes mellitus, but any relationship to anosacral cutaneous amyloidosis is unclear.

CONCLUSIONS

No cases of this cutaneous disorder have been reported in the Western literature; there seems to be a racial difference accounting for the disease, although the precise factor is not clarified yet. The disease could easily be misdiagnosed as lichen simplex chronicus, postinflammatory hyperpigmentation or tinea cruris; therefore, a thorough history, a careful physical examination and a skin biopsy is needed to establish a firm diagnosis.

Differential requirements of the MAP kinase and PI3 kinase signaling pathways in Src- versus insulin and IGF-1 receptors-induced growth and transformation of rat intestinal epithelial cells

There have been few studies on the specific signaling pathways involved in the transformation of epithelial cells by oncogenic protein tyrosine kinases. Here we investigate the requirement of MAP (MAPK) and phosphatidylinositol 3- (PI3K) kinases in the transformation of rat intestinal epithelial (RIE) cells by oncogenic forms of insulin receptor (gag-IR), insulin-like growth factor-1 receptor (gag-IGFR), and v-Src. MAPK is not significantly activated in cells transformed by gag-IR and gag-IGFR but is activated in v-Src transformed cells. Treatment with PD98059, a MEK inhibitor, at concentrations where MAPK activity was reduced below the basal level showed that MAPK is partially required for the monolayer growth of parental and transformed RIE cells. However, MAPK is not essential for the focus forming ability of the three oncogene-transformed cells. It is also not necessary for the colony forming ability of gag-IR- and gag-IGFR-, but is partially required for v-Src-transformed cells. PI3K is significantly activated in all three oncogene transformed RIE cells. LY294002, a PI3K inhibitor, potently inhibited monolayer growth of all three oncogene-transformed cells. However, at concentrations of LY294002 where activated forms of Akt, a downstream component of the PI3K pathway, were undetectable, colony and focus forming abilities of the v-Src-RIE cells were only slightly affected whereas those of gag-IR/IGFR-RIE cells were greatly inhibited. These results were confirmed using a different pharmacological inhibitor, wortmannin, and a dominant negative form of PI3K, Ap85. Similarly, rapamycin, known to inhibit p70S6 kinase, a downstream component of the PI3K-Akt pathway, also inhibited gag-IR/IGFR-induced, but not v-Src-induced, focus and colony formation. We conclude that the MAPK and PI3K signaling pathways are differentially required for transformation of RIE cells by oncogenic IR and IGFR versus Src and the pattern of requirements is different from that of fibroblast transformation.

A study of secondary cutaneous amyloidosis in basal cell carcinoma in Chinese patients: lack of correlation with bcl-2 or p53 protein expression

Pigmented basal cell carcinoma (BCC) is an uncommon form of BCC among Caucasians. In contrast, the majority of BCC in Orientals are pigmented BCC. To assess the occurrence of secondary amyloid deposits in BCC among Chinese patients, a retrospective study was conducted on 53 BCC specimens. We used a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling method for detecting the apoptotic cells. In addition, immunohistochemical staining was performed to examine the expression of the B-cell leukemia/lymphoma-2 gene (bcl-2) and p53 protein. Of the 53 BCC specimens, 37 (69.8%) were pigmented BCC and 31 (58.5%) showed amyloid deposits in the stroma of the tumor cells. The mean percentage of apoptotic tumor cells was 0.29%. Immunostaining of bcl-2 and p53 was detected in 33 BCCs (62.3%) and 19 BCCs (35.8%), respectively. No relationship between amyloid deposition and the number of apoptotic cells was found. In addition, there was no correlation between amyloid deposition and bcl-2 protein expression or between amyloid deposition and p53 protein expression. Our results indicate that the frequency of secondary amyloidosis in BCC among Chinese patients is not higher than that reported in the West. Although no correlation could be detected between amyloid deposition and bcl-2/p53 protein expression, the possible role of apoptosis in the pathogenesis of amyloid deposition in BCC still needs further investigation.

The distribution of monogenean parasites on aquatic vertebrates inhabiting Chinese inland waters

The general distribution of monogenean parasites of aquatic vertebrates inhabiting Chinese inland waters is summarised. Five hundred and seventy-two out of a total of 581 species of monogeneans were discovered on fish, while only nine species were found on Amphibia and Reptilia. Most dactylogyrids and diplozoids parasitise cyprinids, while ancyrocephalids occur on silurids and cyprinids, and gyrodactylids are found mainly on cyprinids and cobitids. Analyses of host-specificity and host-diversity suggests that the family Ancyrocephalidae should be divided into several families parallel with the Dactylogyridae. Of 12 subfamilies of the Cyprinidae, only the Gobiobotinae was found to be free of infection with monogeneans, and the genus Dactylogyrus has more species than any other monogenean genus associated with every cyprinid subfamily.

Hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia was first described by Thurnam in 1848. It is a rare, X-linked, recessive disorder characterized by anhidrosis or hypohidrosis, hypotrichosis, dental hypoplasia and characteristic facial features. Herein, we report a typical case of hypohidrotic ectodermal dysplasia. A 20-year-old male presented with the above symptoms at birth. When a family history was taken, it was discovered that his uncle (mother's brother) had the same characteristic facial features and hypotrichosis.

Inhibitory effect of resveratrol on interleukin 6 release by stimulated peritoneal macrophages of mice

In the present investigation, interleukin 6 (IL-6) activity in the supernatant of cultured mouse peritoneal macrophages was monitored using a sensitive bioassay involving the IL-6-dependent murine hybridoma B9 cell line. The effects of resveratrol on Il-6 release by mouse peritoneal macrophages stimulated with calcium ionophore A23187 and fMLP were explored. Resveratrol, at a concentration range from 5 x 10(-6) to 4 x 10(-5) mol.l-1, was found to dose-dependently inhibit IL-6 release by cultured macrophages induced by A23187 and fMLP, and showed no direct cytotoxic effect, but induced proliferation of cultured mouse thymus cells. Resveratrol, at a concentration range from 10(-8) to 10(-5) mol.l-1, was shown to dose-dependently inhibit calcium ion influx into the cells with the stimulation of fMLP (10(-6) mol.l-1). These results suggest that the blocking of calcium ion influx into cells by reveratrol is one of the possible mechanisms of the IL-6 biosynthesis inhibitory action of resveratrol.

Artificial neural networks: a potential role in osteoporosis

Artificial neural networks are computer software systems that recognize patterns in complex data sets. A recent development in neural computing, multiversion systems (MVS), has led to enhanced analytical power, and this was harnessed to demonstrate the value of risk factors in predicting the result of osteoporosis investigations by quantitative ultrasound. 274 women were screened in an open-access osteoporosis service. A conventional risk factor questionnaire was completed for each patient by the osteoporosis specialist nurse. An MVS was trained on 180 randomly selected data sets and tested on the remaining 94. The results were compared with those from logistic regression analysis in predictive power, both from the selected 20-item questionnaire and for a limited 5-item questionnaire comprising age, height, height loss, weight and years since the menopause. The MVS approach predicted the T-score categorization of the patients from the 20-item questionnaire with 83.0% accuracy, whereas logistic regression yielded an accuracy of only 72.8% (P = 0.04). From the 5-item database the MVS yielded a best prediction accuracy of 73.1%, whereas the logistic regression prediction accuracy was 60% (P = 0.04). These results suggest that 20 risk factors can be used by an MVS to predict the outcome of osteoporosis investigations with a power that outperforms conventional statistical methods. Use of this system may improve the selection of patients for osteoporosis investigations, since even with only 5 risk factors the system performs nearly as well as that based on the full 20 factors.

Inverse relationship between Leydig cell density and metastatic potential of prostatic adenocarcinoma

PURPOSE

Evaluate the relationship between metastatic potential of prostatic adenocarcinoma (PC) and testicular Leydig cell density.

MATERIALS AND METHODS

Tissue samples from 111 men, age 52-85, with PC and bilateral orchiectomy were evaluated for Leydig cell density. The patients were divided into two groups: Group A were patients with metastasis (n = 36) and Group B were patients without metastasis (n = 75). Leydig cell density was determined by direct manual microscopic cell count on the tissue sections. The means of cell counts by four pathologists, expressed as cell/0.78 mm2 were used for analysis. The normally distributed data were analyzed by two-tail Student's t-test. Thirty-eight age-compatible autopsy cases who died of unrelated causes served as normal controls.

RESULTS

The mean of Leydig cell count in group A patients was 14.43 (14.43+/-1.19 SE). Mean of Group B was 47.05 (47.05+/-4.05 SE) whereas normal controls displayed a mean of 48.66 (48.66+/-2.94 SE). Group A was significantly different from control (p < 0.00001). Group A and Group B were also significant different (p < 0.001) whereas control was not significantly different from Group B (p > 0.75).

CONCLUSIONS

Patients with metastatic adenocarcinoma of prostate, as a group, have a significantly lower Leydig cell density than patients without metastasis or patients without PC in compatible age groups. The hormonal relationship between this observation is however unknown. One possible explanation is that PC subpopulation with metastatic potential may require different level of endogenous androgen or are androgen-independent.

Characterisation of rhizobia from African acacias and other tropical woody legumes using Biolog and partial 16S rRNA sequencing

A Biolog (sole carbon source utilisation) user database of tropical and temperature rhizobial strains was created and used in conjunction with the partial 16S rRNA sequencing method to characterise 12 rhizobial isolates from African acacias and other tropical woody legumes. There was close agreement between the two methods but also some significant discrepancies. A high degree of diversity was shown in the relatively small sample of isolates, with 4 out of 5 of the currently proposed rhizobial genera represented. This is the first time Biolog has shown congruence with genotypic fingerprinting using a wide selection of rhizobial reference and test strains.

Intrasynaptosomal free calcium and nitric oxide metabolism in central nervous system oxygen toxicity

BACKGROUND

Central nervous system (CNS) oxygen (O2) toxicity is complex, and the etiology of its most severe manifestation, O2 convulsions, is yet to be determined. A role for nitric oxide (NO) has been proposed, although recent data have indicated that NO is synthesized from L-arginine by an enzyme, NO synthase (NOS). The enzyme is dependent on free calcium (Ca2+) concentration, therefore increases in intracellular Ca2+ may constitute the physiological and pathophysiological mechanisms for stimulating the synthesis of NO.

METHODS

In this study, the intrasynaptosomal free calcium concentration ([Ca2+]i) was measured by the fluorescence of fura-2/AM, and cGMP (as an indirect marker of NO levels) was by radioimmunoassay (RIA) in the rat hippocampus after hyperbaric oxygen (HBO) exposure. We also investigated the effects of daurisoline (DSL, calcium channel blocker) and N-nitro-L-arginine (LNNA, NOS inhibitor) on the above biochemical parameters and the development of oxygen toxicity.

RESULTS

The results show that when the rats were exposed to HBO at 0.5 MPa the intrasynaptosomal Ca2+ and cGMP levels increased by two and three times, respectively, whereas with the use of DSL prior to HBO, the accumulation of [Ca2+]i and cGMP dropped to 56% and 60%, correspondingly. In the rats medicated with LNNA prior to HBO. [Ca2+]i and cGMP levels dropped to 70% and 36% of the HBO group. At the same time, the appearance of CNS oxygen toxicity was delayed and the survival rate increased. The protective effects of LNNA were reversed by L-arginine pretreatment. These findings suggest that the neuronal Ca2+ overload during HBO exposure is a major factor in the pathogenesis of CNS O2 toxicity, and cGMP-NO pathways may be directly involved in HBO-induced seizures.

[Production and secretion of interleukin 6 from stimulated peritoneal macrophages of the mouse]

In this paper, a bioassay method involving the interleukin 6 dependent murine hybridoma B9 cell line was used to detect the level of released and cell-associated interleukin 6 in resident peritoneal macrophages from the mouse. The phorbol ester, phorbol 12-myristate 13-acetate (PMA), the calcium ionophores A23187, the chemotactic peptide fMLP and lipopolysaccharide(LPS) were introduced in these experiments as stimulators. PMA, A23187 and fMLP were shown to induce a dose-dependent increase of both released and cell-associated interleukin 6, whereas, LPS caused increase of interleukin 6 activity in supernatants of cultured peritoneal macrophages of the mouse. The effects of PMA and A23187 suggested that the pathway of PKC and calcium is involved in the production and secretion of interleukin 6. The effects of fMLP and LPS provided evidence that they participated in the process of inflammation. The difference between LPS and the other three stimulators in cell-associated interleukin 6 activity might suggest a different mechanism of actions of generation of interleukin 6.

[Determination of puerarin in plasma by high performance liquid chromatography]

A high performance liquid chromatography with fluorescence detection has been developed for determination of puerarin in plasma using a column of YWG-C16 (10 microns) and mobile phase of methanol (450 ml)-water (522.5 ml)-0.1 mol.L-1 phosphate buffer (pH 7.4, 27.5 ml). The preparation of samples was as follows: Transfer 0.1 ml of plasma into a 1 ml stoppered glass tube containing daidzein as internal standard, add 0.4 ml of absolute alcohol to deproteinize the plasma, vortex for 2 min, centrifuge for 15 min at 2800 r.min-1 and inject 20 microliters of the supernatant into the HPLC column. Linear calibration curve was obtained by plotting concentration vs peak height ratio over the range 0.03-12.00 micrograms.ml-1 with a correlation coefficient of 0.999. The average recovery of puerarin was 95.3% and the average RSD was 4.8%. The minimum detectable quantity of puerarin was 0.04 ng, equivalent to 10 ng.ml-1 plasma. This method is highly sensitive, specific, simple and rapid. The plasma concentration-time course of puerarin given i.v. 2.25 mg.kg-1 to two dogs determined by this method was found to fit a two-compartments open model with T1/2 alpha of 6.0 min and T1/2 beta of 57.4 min.

[Study on effect of reinforcing kidney and invigorating spleen principle on severe asthma]

OBJECTIVE

To explore on prevention and treatment of severe asthma with reinforcing the Kidney and invigoration the Spleen Principle (RKISP) and its mechanism.

METHODS

Patients were treated with steroid aerosol (as control group), and both steroid aerosol and RKISP (as test group) respectively.

RESULTS

The markedly effective rate of the test group was higher than that of the control group, the doses of beta-analeptic and the side-effect rates of the test group were lower than that of the control group, the pulmonary function of the test group was more remarkably improved. After treatment, the T cell hyperplasia response to specific allergen, the basophilic cell releasing capacity, the serum IgE and eosinophil of the test group were all reduced more obviously than those of the control group. In the control group, the neutrophil increased and the neutrophil phagocytic capability as well as the function of adrenal cortex were declined. While in the test group, the neutrophil phagocytic capability was raised, the neutrophil and the function of adrenal cortex had no significant changes.

CONCLUSIONS

RKISP cooperated with steroid in relieving attack of asthma, and it was more important for it to display an obvious modulation action on immune and neuroendocrine system.

Subcutaneous xenotransplantation of hybrid artificial pancreas encapsulating pancreatic B cell line (MIN6): functional and histological study

The biohybrid artificial pancreas is designed to enclose pancreatic tissues with a selectively permeable membrane that immunoisolates the graft from the host immune system, allowing those endocrine tissues to survive and control glucose metabolism for an extended period of time. The pancreatic B cell line MIN6 is established from a pancreas B cell tumor occurring in transgenic mice harbouring the human insulin promoter gene connected to the SV40 T-antigen hybrid gene. It has been proven that glucose-stimulated insulin secretion in MIN6 cells retains a concentration-dependent response similar to that of normal islets. In this study, we performed the histological and functional examination of three-layer microbeads employing MIN6 cells after subcutaneous xenotransplantation to evaluate this device as bioartificial pancreas. MIN6 cells were microencapsulated in three-layer microbeads formulated with agarose, polystyrene sulfonic acid, polybrene, and carboxymethyl cellulose. Microbeads were xenogenically implanted in the subcutaneous tissue of the back of Lewis rats with streptozotocin-induced diabetes. One week after implantation, microbeads were retrieved and cultured for 24 h before the static incubation. There was no evidence of adhesion to the graft and the fibrosis in the transplantation site as determined by gross visual inspection. Microscopic examination demonstrated that retrieved microbeads maintained normal shape, containing intact MIN6 cells. Histological study showed that these MIN6 cells in the microbeads appeared to be viable without cellular infiltration within or around the microbeads. Immunohistochemical analysis of the microbeads clearly revealed the intense staining of insulin in the cytoplasm of encapsulated MIN6 cells. Insulin productivity of MIN6 cells in the microbeads is strongly suggested to be preserved. In response to 16.7 mM glucose stimulation, static incubation of microbeads 1 wk after implantation caused the 2.3 times increase in insulin secretion seen after 3.3 mM glucose stimulation (84.3 +/- 10.0 vs. 37.4 +/- 10.7 microU/3 x 10(6) cells/hr, n = 5 each, p < 0.01). This study demonstrates that three-layer microbeads encapsulating MIN6 cells retain excellent biocompatibility and maintain good insulin secretion even after subcutaneous xenotransplantation, suggesting the possible future clinical application of this unique bioartificial pancreas to subcutaneous xenotransplantation.

A newly developed three-layer agarose microcapsule for a promising biohybrid artificial pancreas: rat to mouse xenotransplantation

We examined the effectiveness of an improved version of a three-layer agarose microcapsule in islet xenotransplantation. The microcapsule is composed of a mixture of 5% agarose and 5% polystyrene sulfonic acid. The other two outer layers are polybrene and carboxymethyl cellulose. The agarose/polystyrene sulfonic acid membrane is for the purpose of immunoisolation, suppression of complement activity and reinforcement of the microcapsule. The polybrene layer suppresses the polystyrene sulfonic acid leakage by forming a polyionic complex at the surface of the agarose/polystyrene sulfonic acid membrane. The outermost layer, a carboxymethyl cellulose coating, improves the biocompatibility of the microcapsule. In vitro static incubation study showed that the insulin secretion from rat islets in microcapsules in response to 16.7 mM glucose stimulation was more than four times higher than that on 3.3 mM glucose stimulation (n = 8). In an in vivo study, 500 rat islets in microcapsules were xenogenically implanted in the abdominal cavity of mice with streptozotocin-induced diabetes. The graft survival times ranged from 2 to 5 mo, the average being 75 days (n = 5). Our results demonstrate that the improved version of the three-layer agarose microcapsule can effectively prolong the xenograft survival time without employing immunosuppressants, suggesting that this microcapsule could provide a promising biohybrid artificial pancreas for future clinical applications.

Equilibrium and attractivity analysis for a class of hetero-associative neural memories

Based on the natural structure of Kosko's Bidirectional Associative Memories (BAM), a high-performance, high-capacity associative neural model is proposed which is capable of simultaneous hetero-associative recall. The proposed model, Modified Bidirectional Decoding Strategy (MBDS), improves the recall rate by adding some association fascicles to Kosko's BAM. The association fascicles are sparse coding neuron structures that provide activating strengths between two neuron fields (say, field X and field Y). The sufficient conditions for a state to become an equilibrium state of the MBDS network is derived. Based on these results, we discuss the basins of attraction of the training pairs in one iteration. The upper bound of the number of error bits which can be tolerated by MBDS is also derived. Because the attractivity of a stored training pair can be increased markedly with the aid of its corresponding association fascicles, we recommend a high capacity realization of MBDS, Bidirectional Holographic Memory (BHM), so that each training pair is stored uniquely and directly in the connection weights rather than encoded in a correlation matrix. Finally, computer simulations demonstrate the attractiveness of three different realizations of MBDS to verify our results.

[A genetic epidemiologic study on HBsAg chronic carriers]

375 Individuals from 23 HBsAg positive families were investigated in the study. The results showed that HBsAg carrier rate among blood relatives was significantly higher than non-blood relatives (P < 0.01); HBsAg carrier rate decreased with the order of the first, second and third degree relatives (P < 0.01); and the rate in the individuals living together with the probands was higher than those living apart (P < 0.01). However, the other two markers of HBV infectivity, anti-HBs and anti-HBc, did not show any differences mentioned above. The results analysed by means of dichotomy and Logistic regression model, showed that blood relationship played an important role in HBsAg carrier state. In addition, the history of sharing living facilities was related to HBsAg carrier state. The average heritability in the first, second and third degree relatives was 79.68%. The analysis of genetic model showed that HBsAg carrier state was corresponded to the characteristic of multifactorial genetic disease, excluding the possibility of genetic disease due to single gene.

Improvement of projection-type associative memories by using a two-phase recalling procedure

In this letter, we propose a Two-Phase Recalling Procedure (TPRP) to improve the recall capability of the projection-type associative memory. It is known that the conventional projection dynamic sometimes produces spurious states that do not belong to the space spanned by the prototype vectors (memory space). The proposed TPRP provides a trapped spurious state another chance to project onto the memory space such that the recall capability of the projection-type associative memories can be greatly improved. Finally a simulation result demonstrates the effectiveness of the TPRP.

[Study on effect of strengthening body resistance method on asthmatic attack]

In order to study the effect of strengthening body resistance method on asthmatic attack, asthma patients of Cold type and Heat type were treated with symptomatic treatment (as control groups), and treatment both on the principal and secondary aspect (as test group) respectively. The results showed that the markedly effective rates of the test groups of both type were higher than that of the two control groups. In test groups after treatment, the 1 second forced expiratory volume (FEV1) and the maximal expiratory flow increased markedly, the human leucocyte antigen carrying (HLA-DR+) T cell ratio, the basophilic cell releasing capacity (HBR) and the T cell hyperplasia response to specific allergen were all reduced. While in the control groups, these criteria had no significant changes after treatment. These results suggested that the strengthening body resistance method displayed an obvious regulating action in relieving attack of asthma.