Numerical simulation and testing of laser-MIG hybrid-welding angle-structure sheets

Numerical simulation and experimental investigation of laser-MIG hybrid angle-welding low-carbon 1.5-mm-thin SPCC steel sheets are presented in this work. The transient simulation analysis provides an access to the thermal-fluid phenomena prediction by employing a hybrid three-dimensional heat source model. Special attention is paid to the melt dynamic behaviors within the triangular molten pool affected by the Marangoni convection. The simulation results show that the temperature and its gradient distribution are symmetrical with respect to the laser beam, which is validated well by the experimental study. The microstructure of the welded joints was analyzed by scanning electron microscopy and transmission electron microscopy. The results show that the cross-section microstructures of welded joint are mainly composed of the weld zone, narrow heat-affected zone, and substrate. The semielliptic-like molten pool shape is consistent with that of the simulated results. The finer microstructure in the weld bead results from the rapid cooling rate of laser welding confirmed by the FEM calculation. The columnar and equiaxed dendrites are formed in the peripheral and central region of the molten pool, which is beneficial for the improvement of the microhardness.

Effects of powder size and preset thickness on the microstructure and properties of Ni35 thin coating prepared by laser cladding

Ni35 thin coatings were prepared on 40Cr steel by preset powder laser cladding technology. The effects of powder size and preset thickness on the dilution rate, microstructure, and properties of the coating were systematically studied. The results showed that the coating with smaller powder size and larger preset thickness had smaller grain size, denser microstructure, a flatter bottom of the molten pool, and lower dilution rate. The micro-hardness of the coating with large powder size and preset thickness was higher. The friction coefficient of the coating with small powder size and small preset thickness was smaller, but the latter had larger curve fluctuation and wear volume loss. The corrosion rate of the coating was high during the first 24 h, then relatively stable after 68 h, and the corrosion rate and loss of the coating with small powder size and large preset thickness were smaller.

Microstructure evolution and wear behavior of AISI 304 stainless steel after Nd:YAG pulsed laser surface melting

The microstructure and wear behavior of AISI 304 stainless steel after Nd:YAG pulsed laser surface melting (LSM) were investigated. The microstructural features of the LSM layer were characterized by field emission scanning electron microscope and high-resolution transmission electron microscope. Experimental results showed that the microstructure was obviously refined to the nano- and sub-micrometer scales on the AISI 304 stainless steel surface after LSM treatment. Fine grains with grain size of less than 200 nm were obtained when the applied laser energy densities were in the range of 1.90×10⁷ to 3.52×10⁷J/m² during LSM. The results indicated that the calculated surface temperature, cooling rate, and measured grain size are closely related to the adopted laser energy densities. The lower the laser energy density is, the lower the surface temperature, and the faster the cooling rate, the finer the grain size. In addition, the microhardness and wear resistance of the stainless steel was significantly improved. Finally, the wear mechanism after LSM process was revealed.

GCH1 plays a role in the high-altitude adaptation of Tibetans

Tibetans are well adapted to high-altitude hypoxia. Previous genome-wide scans have reported many candidate genes for this adaptation, but only a few have been studied. Here we report on a hypoxia gene ( GCH1, GTP-cyclohydrolase I), involved in maintaining nitric oxide synthetase (NOS) function and normal blood pressure, that harbors many potentially adaptive variants in Tibetans. We resequenced an 80.8 kb fragment covering the entire gene region of GCH1 in 50 unrelated Tibetans. Combined with previously published data, we demonstrated many GCH1 variants showing deep divergence between highlander Tibetans and lowlander Han Chinese. Neutrality tests confirmed a signal of positive Darwinian selection on GCH1 in Tibetans. Moreover, association analysis indicated that the Tibetan version of GCH1 was significantly associated with multiple physiological traits in Tibetans, including blood nitric oxide concentration, blood oxygen saturation, and hemoglobin concentration. Taken together, we propose that GCH1 plays a role in the genetic adaptation of Tibetans to high altitude hypoxia.

EP300 contributes to high-altitude adaptation in Tibetans by regulating nitric oxide production

The genetic adaptation of Tibetans to high altitude hypoxia likely involves a group of genes in the hypoxic pathway, as suggested by earlier studies. To test the adaptive role of the previously reported candidate gene EP300 (histone acetyltransferase p300), we conducted resequencing of a 108.9 kb gene region of EP300 in 80 unrelated Tibetans. The allele-frequency and haplotype-based neutrality tests detected signals of positive Darwinian selection on EP300 in Tibetans, with a group of variants showing allelic divergence between Tibetans and lowland reference populations, including Han Chinese, Europeans, and Africans. Functional prediction suggested the involvement of multiple EP300 variants in gene expression regulation. More importantly, genetic association tests in 226 Tibetans indicated significant correlation of the adaptive EP300 variants with blood nitric oxide (NO) concentration. Collectively, we propose that EP300 harbors adaptive variants in Tibetans, which might contribute to high-altitude adaptation through regulating NO production.

[Influence of the Arg-Gly-Asp-Ser sequence on the biological effects of bioactive glass on human dental pulp cells]

OBJECTIVE

Positive effects of bioactive glass (BG) on proliferation, mineralization, and differentiation of human dental pulp cells (hDPCs) was already verified in various former studies. The Arg-Gly-Asp-Ser sequence (RGDS) was confirmed of affecting cell adhesion. Before further investigation, the objective of this study is to investigate whether RGDS can affect the effects of BG on the adhesion, proliferation and mineralization of hDPCs.

METHODS

hDPCs were harvested from third molars of 18-25-year-old individuals after informed consent. Enzyme digestion technique was used. The 4th to 6th generation of hDPCs were used for all experiments. The cells of the experimental groups were cultured in Dulbecco minimum essential medium (DMEM) containing ionic dissolution products of BG and RGDS of several concentrations (12.5 mg/L, 25.0 mg/L, 50.0 mg/L, 100.0 mg/L, 200.0 mg/L). DMEM containing ionic dissolution products of BG without RGDS was used for cell culture as control group. Cell adhesion was tested 4 h after cell seeding by MTT assay. Cell proliferation was examined at 1, 3, 5, 7, and 9 d after cell seeding by MTT assay. Cell mineralization was investigated on days 14 and 28 by alizarin red staining. After being stained and dried, mineralized nodules were dissolved by cetylpyridinium chloride (CPC) for semi-quantitative test. Results were statistically analyzed by one way ANOVA, SPSS (version 19.0) and P<0.05 was considered to be significant.

RESULTS

Cell adhesion in BG group showed no difference from that in DMEM group. Compared with BG group, hDPCs in BG+RGDS groups suggested weaker cell adhesion.When the concentration of RGDS increased, the adhered cell number decreased. hDPCs cultured with BG and RGDS showed lower proliferation activity in the early stage, while no significant difference was observed after 3 d. BG group promoted the mineralization of hDPCs compared with positive control group, negative control group and RGDS group. No significant difference was observed between BG+RGDS group and BG group or between RGDS group and positive control group.

CONCLUSION

BG promotes proliferation and mineralization without affecting cell adhesion of hDPCs. Unbounded RGDS inhibits cell adhesion, but has no influence on the positive effects of BG on the proliferation and mineralization of hDPCs.

[Effects of bioactive glass and extracted dentin proteins on human dental pulp cells]

OBJECTIVE

To investigate the proliferation, odontogenic differentiation and mineralization of human dental pulp cells (HDPCs) on bioactive glass(BG) and extracted dentin proteins(EDP).

METHODS

Primary HDPCs were isolated from third molars by enzyme digestion and were cultured in Dulbecco's minimum essential medium (DMEM). Then the 4th generation of HDPCs was cultured with DMEM, which contained BG-EDP, BG, and EDP, respectively. Meanwhile HDPCs were cultured in DMEM as control group. Proliferation of HDPCs was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) colorimetric assay. Odontogenic differentiation was determined by alkaline phosphatase (ALP) activity assay and real-time PCR. Mineralization was investigated by Alizarin red staining and cetylpyridinium chloride (CPC) assay.

RESULTS

The proliferation of HDPCs was increased significantly in BG-EDP group on 3,7,and 9 d (optical density value: 1.36±0.06, 2.52±0.20, 2.72±0.29) compared with BG (optical density value: 1.20±0.26, 2.33±0.26, 2.50±0.30), EDP(optical density value: 1.13±0.15, 2.10±0.13, 2.38±0.22) and control group (optical density value: 0.84±0.17, 1.84±0.18, 1.95±0.19), P<0.05. After 7 days, ALP activity of BG-EDP group had no statistical difference compared with EDP group and control group; the expression of odontogenic differentiation genes (DSPP, DMP-1) showed no difference among all the groups(P>0.05). After 14 days, ALP activity of BG-EDP group (56.67±1.83) was significantly upregulated compared with EDP group (41.98±9.71) and control group (30.82±6.70), P<0.05, but had no statistical difference compared with BG group (56.29±6.20), P>0.05; DSPP gene expression was upregulated significantly in BG-EDP group (5.79±1.94) compared with the other groups (P<0.05); DMP-1 gene expression of BG-EDP group (3.87±1.87) increased but had no statistical difference compared with the other groups (P>0.05). The alizarin red staining showed more mineral nodules in BG-EDP group, the cetylpyridinium chloride semi-quantification presented higher calcification in BG-EDP group (0.27±0.01) compared with the other groups (P<0.05).

CONCLUSION

Compared with either BG or EDP, BG-EDP significantly promotes the proliferation, odontogenic differentiation and mineralization of HDPCs.

A genetic adaptive pattern-low hemoglobin concentration in the Himalayan highlanders

Mean hemoglobin (Hb) concentration of about 3 500 subjects derived from 17 studies of Himalayan highlanders (Tibetans, Sherpas, and Ladakhis) was compared with lowlanders (Chinese Han, Indian Tamils) lived in the Himalayas, and European climbers during Everest expeditions as well as Andean natives. The results found that Hb concentration in Himalayan highlanders was systemically lower than those reported for Andean natives and lowland immigrants. These comparative data demonstrated that a healthy native population may successfully reside at high altitude without a significant elevation in Hb, and the lower Hb levels of Himalayan highlanders than those of migrated lowlanders and Andean natives are an example of favourable adaptation over the generations. In addition, excessive polycythemia has frequently been used as a marker of chronic mountain sickness (CMS). Altitude populations who have a higher Hb concentration also have a higher incidence of CMS. The low Hb in Himalayans suggested as showing adaptation over many generations in Tibetan stock. Recent work in Tibet, suggested that Tibetans there may have adapted to high altitude as a result of evolutionary pressure selecting for genes which give an advantage at altitude. All of the population genomic and statistical analysis indicated that EPAS1 and EGLN1 are mostly likely responsible for high altitude adaptation and closely related to low Hb concentration in Tibetans. These data supported the hypothesis that Himalayan highlanders have evolved a genetically different erythropoietic response to chronic hypoxia by virtue of their much longer exposure to high altitude.

[Integripetal rhodiola herb attenuates high altitude-induced pulmonary arterial remodeling and expression of vascular endothelial growth factor in rats]

The aim of this study was to investigate the effect of integripetal rhodiola herb on pulmonary arterial remodeling and expression of vascular endothelial growth factor (VEGF) in high altitude pulmonary hypertension in rats. Fifty healthy male Wistar rats were divided into five groups randomly: Plain control group (LC group), 10-day plateau group (H(10) group), 30-day plateau group (H(30) group), 10-day rhodiola-treated plateau group (R(10) group), and 30-day rhodiola-treated plateau group (R(30) group). Each group included 10 rats. The rats in LC group were kept in Chengdu (500 meters above sea level), and rats in H and R groups were kept in Lhasa (3 700 meters above sea level). The rats in R group were daily treated with integripetal rhodiola herb extract (24%, 10 mL/kg) intragastrically for 10 d or 30 d, while rats in LC and H groups were treated with the same volume of saline. Mean pulmonary arterial pressure (mPAP) was detected via a catheter in the pulmonary artery by pressure waveform monitoring. The ratio value of right ventricle weight to left ventricle plus septum weight [RV/(LV + S)] was measured. The microstructure of pulmonary arterioles was examined by electron microscopy. The expression of VEGF in the lung was investigated using immunohistochemistry. The results showed that mPAP and [RV/(LV + S)] in H(10) group and H(30) group were higher than those in LC group (P < 0.05); but there was no significant difference between H(10) group and R(10) group (P < 0.05); and mPAP and [RV/(LV + S)] in H(30) group were lower than those in H(30) group (P < 0.05). Electron microscopy showed that compared to LC group, arteriolar endothelial cells were arranged in a columnar or palisading form, protruding into the lumen, accompanied with luminal stenosis, irregular internal elastic membrane, and proliferation of vascular smooth muscle cells in H groups, which was more obvious in H(30) group than in H(10) group; while these pathological changes were attenuated in the R groups compared to H groups. The levels of VEGF protein in H groups were also higher than those in LC group (P < 0.05); while the expression of VEGF in R(30) group was lower than that in H(30) group. In summary, the results show that the integripetal rhodiola herb can attenuate high altitude-induced pulmonary arterial remodeling in rats, and the inhibition of VEGF protein expression by rhodiola may be one of the mechanisms.

Microstructure of a newly developed γ′ strengthened Co-base superalloy

The microstructure of a newly developed Co-base superalloy with enhanced high-temperature strength has been investigated using transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP) techniques. It mainly consists of a typical gamma/gamma' (FCC/L1(2)) structure and a plate-shaped AB3-type (Ni,Co,Cr)3(Ti,Al) intermetallic compound with hexagonal structure (a approximately 5.1A and c approximately 12.5A). gamma' is formed with a bimodal distribution and fine gamma' has a cuboidal morphology. Cr and Co are enriched in the gamma phase, while Ti, Al and Ni are enriched in the gamma' phase. W and Mo are more or less uniformly distributed in both gamma and gamma'. Chemical composition analysis by 3DAP suggests that the plate-shaped phase has a higher Ti and lower Al content compared to that of gamma' phase, and the concentration of Ti, Co and Ni has a periodic variation along c-axis with a period of 12.5A in the plate-shaped phase.

Polymorphisms of renin-angiotensin system in essential hypertension in Chinese Tibetans

OBJECTIVE

To evaluate the potential implications of the genetic variability of angiotensin converting enzyme, angiotensinogen and angiotensin II type 1 receptor gene for essential hypertension in Tibetan.

METHODS

A case-control study was conducted in 173 hypertensive individuals and 193 individuals with normal blood pressure. Multiple logistic regression analyses were used to estimate the risks of developing hypertension for different genotypes, and haplotype analyses of the angiotensinogen gene were used to determine the association between two-locus angiotensinogen gene polymorphisms and hypertension.

RESULTS

As to the risk to high blood pressure and high systolic pressure, women with MM genotype were 7.7 (95% CI: 1.3-20.5) and 8.7 (95% CI: 1.8-20.1) times higher than those with TT genotype after adjustment for age and body mass index. Haplotype frequencies for M235T and G-6A were significantly different between hypertensive individuals and controls, which indicated an association of angiotensinogen gene haplotypes with hypertension, and a significant association of 235T/-6A haplotype with hypotensive effect.

CONCLUSION

Our results suggest that angiotensinogen gene 235MM is a predictor for hypertension development in Tibetan women but not in men, and may exert its hypertensive effect on linkage disequilibrum with a possible function locus of G-6A.

Ectodysplasin-A1 is sufficient to rescue both hair growth and sweat glands in Tabby mice

Mutations in the human ectodysplasin-A (EDA) are responsible for the most common form of the ectodermal dysplasia and the defective orthologous gene in mice produces the tabby phenotype, suggesting its vital role in the development of hair, sweat glands and teeth. Among several EDA splice isoforms, the most common and the longest EDA splice isoforms, EDA-A1 and EDA-A2, differing by only two amino acids, activate NF-kappaB-promoted transcription by binding to distinct receptors, EDAR and XEDAR. The extent to which any particular isoform is sufficient for the formation of hair, sweat glands or teeth has remained unclear. Here we report that transgenic expression of the mouse EDA-A1 isoform in tabby (EDA-less) males rescued development of several skin appendages. The transgenic tabby mice showed almost complete restoration of hair growth, dermal ridges, sweat glands and molars. The number of hair follicles in the transgenic mice is the same as in wild-type; though the development of follicles and associated glands varies from indistinguishable from wild-type to smaller and/or only partially formed. These results suggest that the other EDA isoforms may not be absolutely required for skin appendage formation, but consistent with distinctive temporal and spatial expression of the EDA-A2 isoform, are likely required for appropriate timing and completeness of development. Our data provide the first direct physiological evidence that EDA-A1 is a key regulator of hair follicle and sweat gland initiation; its soluble ligand form could aid in deriving therapeutic reagents for conditions affecting hair and sweat gland formation.

A study of apoptosis in Merkel cell carcinoma: an immunohistochemical, ultrastructural, DNA ladder, and TUNEL labeling study

We performed immunohistochemical, ultrastructural, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL), and DNA ladder studies of apoptosis in nine cases of Merkel cell carcinoma (MCC). None of the cases showed spontaneous regression as has been reported in several MCCs. Neuron-specific enolase was demonstrated by immunohistochemistry (8/8 MCCs), and staining for cytokeratin 20 was positive (2/8 MCCs). Ultrastructural examination revealed many cytoplasmic dense-cored granules, desmosome-like structures, and intermediate filaments. The granules were seen along the plasma membrane or around perinuclear centrioles. We found various stages of development of apoptotic bodies. Apoptosis resulted in vacuolization and fragmentation of nuclei and phagocytosed bodies in tumor cells. Apoptotic cells were also detected by TUNEL, DNA ladder, and immunostaining using the antibody against Fas (Apo- 1/CD95) antigen. It seems that a high apoptotic rate is a common finding in MCC, although spontaneous regression is an exceedingly rare event. It is thus unlikely that apoptosis alone would explain spontaneous regression.

Inhibition of growth of melanoma cells by CD95 (Fas/APO-1) gene transfer in vivo

Interaction of CD95 ligand with its cognate receptor CD95 induces apoptotic cell death. Alterations in this pathway within tumor cells can result in escape from apoptosis and from immune surveillance. Melanoma cells recently were found to escape an immune attack via high expression of CD95 ligand, thereby inducing apoptosis of activated T lymphocytes. When screening four human melanoma cell lines for expression of CD95 and CD95 ligand, respectively, an inverse correlation was found, i.e., cells expressing high levels for CD95 ligand (CD95L(high)) were almost negative for CD95 and vice versa. Since coexpression of CD95 and CD95 ligand may lead to apoptosis by autocrine suicide or fratricide, it was tested whether overexpression of CD95 in CD95L(high) melanoma cells results in apoptotic cell death. Upon transfection with a cytomegalovirus-promoter-driven expression vector encoding the CD95 gene, CD95L(high) melanoma cells underwent apoptosis at a much higher level than CD95L(low) melanoma cells. Apoptosis appeared to be due to the activation of CD95 as cell death was inhibited by cotransfection with a dominant negative mutant for the CD95 signaling protein, Fas-associated protein with death domain. Tumor progression of CD95L(high) melanoma cells transplanted into nude mice was significantly reduced when recipient animals were injected with liposomes containing the CD95 expression vector. As demonstrated by immunohistochemistry and TUNEL staining, in vivo transfected tumor cells expressed CD95 and underwent apoptotic cell death. Hence, this study indicates that delivery of the CD95 gene inhibits tumor growth in vivo and thus might be a therapeutic strategy to treat tumor cells that express high levels of CD95 ligand. J Invest Dermatol 115:1008-1014 2000

Bikunin, a serine protease inhibitor, is present on the cell boundary of epidermis

Bikunin, which is an inhibitor of serine proteases, is widely distributed in human tissues, including liver, kidney, and mucous membranes of the stomach and colon. The aim of this study was to clarify whether bikunin is expressed in human epidermis and its appendages. Immunoblot analysis using a specific polyclonal antibody to bikunin revealed that a single 43 kDa protein is present in the cell lysate from the human keratinocyte cell line HaCaT. Immunohistochemically, dotted reaction products stained with anti-bikunin antibody were localized on the cell boundary in both basal and spinous cell layers, except on the cell boundary of the basal cells facing the basal membrane. There were no reaction products in the granular-horny cell layers. Reaction products stained with anti-bikunin antibody were also observed on the hair bulb cells and eccrine sweat gland cells, but not on apocrine sweat glands. Also, reaction products were observed on the luminal surface of the renal proximal tubules and in the cytoplasm of these cells. In immunoelectron microscopy, gold particles were observed on the cell membranes close to the desmosomal structures. Reverse transcription-polymerase chain reaction and northern blot analyses showed that mRNA specific for bikunin was expressed in HaCaT cells and human epidermal keratinocytes obtained from suction blisters, and was contained in a commercially available human keratinocyte cDNA preparation. These findings indicate that bikunin is expressed in keratinocytes and may play an important part in regulating keratinocytes in either mitosis or inflammation.

Expression of adrenomedullin, a hypotensive peptide, in the trophoblast giant cells at the embryo implantation site in mouse

Adrenomedullin (AM) is a newly discovered hypotensive peptide which is believed to play an important role for blood pressure control in the adult. Although it has been well established that a major production site of AM is vascular endothelial cells, we now show that AM is most highly expressed in trophoblast giant cells, which are derived from the conceptus and are directly in contact with maternal tissues at the implantation site. Northern blot and in situ hybridization analyses show that the AM mRNA begins to be detected just after implantation and its level peaks at 9.5 days postconception (d.p.c.) in those cells. Expression then falls dramatically after 10.5 d.p.c., coincident with the completion of the mature chorioallantoic placenta. Immunohistochemical analyses show that the AM peptide is secreted from the trophoblast giant cells into the surrounding tissues, i.e., embryo, decidua, and maternal circulation. In contrast, the expression of an AM receptor was not detected by Northern blot analyses in either embryo or trophoblast giant cells at 7 d.p.c., when the AM gene is most highly expressed in the trophoblast giant cells. This suggests that the AM produced and secreted from the embryo's trophoblast giant cells acts on the maternal tissues rather than on the embryonic tissues. Based on these results, we propose that the high production of AM may be the mechanism by which the embryos survive at the early postimplantation period by pooling maternal blood in the implantation site in order to secure nutrition and oxygen before the establishment of efficient embryo-maternal circulation through the mature placenta.

Localization of sphingomyelinase in lesional skin of atopic dermatitis patients

Because it has been suggested that the majority of the activity hydrolysing [N-methyl-14C] sphingomyelin is due to sphingomyelin acylase in the lesional skins of atopic dermatitis (AD), in this study we used immunologic techniques to localize and quantitate sphingomyelinase in AD lesional and normal skin. A polyclonal antibody raised against a synthetic polypeptide corresponding to a portion of the amino acid sequence deduced from the cDNA of human acid sphingomyelinase, cross-reacted with a 58 kDa, pI 5.8 human epidermal protein in an immunoblot analysis. The 58 kDa protein-rich fraction, partially purified by immunoprecipitation, converted [N-methyl-14C]-sphingomyelin to 14C-phosphorylcholine and ceramides. The reaction products were immunohistochemically observed in the intercellular domain from the upper spinous cell layer to the upper stratum corneum cell layers in the lesional skin of AD patients. Immunoelectron-microscopically, gold particles appeared to be concentrated in the intercellular domains of the granular-upper stratum corneum cells in the lesional skin of AD patients. The total amount of the 58 kDa protein in a 7 mm2 area of the skin was measured by quantitative immunoblot analysis; and was slightly increased in the lesional skin samples [3.5 +/- 0.3 microg per 7 mm2 (n = 7)], as compared with the nonlesional skin samples of AD patients [2.8 +/- 0.19 microg per 7 mm2 (n = 10)] and with the normal skin samples [2.7 +/- 0.22 microg per 7 mm2 (n = 10)]. This difference (between the lesional skin of AD and the nonlesional skin of AD or the normal control) was significant (nonpaired student's t test, p < 0.05).

Decreased level of prosaposin in atopic skin

In the skin of atopic dermatitis patients, the amount of ceramides in the stratum corneum is decreased. Although the cause of this decrease may be due to the higher activity of acylase, a decrease in the activity of sphingolipid activator proteins may also be the cause. A polyclonal antibody to saposin D, elicited by immunizing rabbits with the synthetic polypeptide from cDNA of saposin D, cross-reacted with a single 65-kDa epidermal protein of pI 5.6 in a 2-dimensional immunoblot study, suggesting that it was prosaposin, the precursor protein of saposin D, from its molecular weight and demonstrating its immunohistochemical localization in the innermost cell layers of the stratum corneum of the skin. The antigenic material was also observed in the epithelium of the esophagus, pneumocytes of the lungs, hepatocytes, and glandular cells of the stomach. Immunoelectron microscopy showed the antigenic material in the cytoplasm of the granular cells and the intercellular spaces, either between the stratum granulosum and the stratum corneum or on the stratum corneum cell envelope. By ELISA, the amount of the 65-kDa protein in the inner surface skin of the upper arm of atopic dermatitis patients (nonlesional skin) [4.1 +/- 2.0 microg per 7 mm2 (mean +/- SD), n = 10] was found to be significantly decreased (p < 0.05) to 66% of that in the normal control (6.2 +/- 1.5 microg per 7 mm2, n = 10). Therefore, the suppression of prosaposin synthesis may be related to the abnormal stratum corneum formation in atopic skin through lower activation of glucosylcerebrosidase or sphingomyelinase.

30-kDa trypsin-like proteases in the plantar stratum corneum

The casein digestible proteases in human plantar stratum corneum were determined to be about 75-kDa, 30-kDa and 25-kDa in molecular weight by zymography. The enzymatic activity of the 75-kDa and 25-kDa proteases was specifically inhibited by chymostatin, which is an inhibitor of chymotrypsin-like serine proteases, and the proteases around 30-kDa were inhibited by leupeptin, a trypsin-like serine protease inhibitor. The enzymatic activity of all these proteases was inhibited by aprotinin. The 30-kDa trypsin-like proteases were heat-stable; their enzymatic activity still remained even after heating at 100 degrees C for 60 minutes. Their optimal pH was around 9, and the activity was higher in the outer part of the stratum corneum than in the inner part.

Decreased expression of filaggrin in atopic skin

The amounts of the epidermal proteins filaggrin, involucrin, cystatin A and Ted-H-1 antigen produced during the terminal differentiation of keratinocytes were immunohistochemically measured in lesional and nonlesional skin of atopic dermatitis (AD) patients. In addition, the amount of filaggrin in the skin of the inner surface of the upper arm of AD patients (nonlesional skin) and normal controls, obtained by punch biopsy, was measured by an enzyme-linked immunosorbent assay (ELISA) technique. The immunohistochemical study showed that all four proteins were decreased in lesional skin. By contrast, only filaggrin was decreased in nonlesional skin of AD patients. The ELISA showed that the amount of filaggrin in the skin of the inner surface of the upper arm was 2.48 +/- 0.45 microgram/7 mm2 (n = 8) in AD patients, which was 32% of that in the normal controls (7.7 +/- 0.55 microgram/7 mm2; n = 4). This decrease in filaggrin production in atopic skin may be one of the reasons why atopic skin can easily become dry, because filaggrin is thought to be the precursor protein of the emollient factors in the stratum corneum. The evidence that only the expression of filaggrin was suppressed in AD patients, though the genes of filaggrin and involucrin are localized to a very restricted portion of the same gene 1q21, indicates that the filaggrin gene does not share regulatory elements with the involucrin gene.

Location of myocardial infarction and its surface cardioelectric representation. An experimental study

In order to explore the relationship between the different location of myocardial infarction (MI) and reflections of pathognomonic Q potentials on the body surface, an experimental study was carried out in 28 dogs. The results were (1) in 27 of a total 28 dogs after MI formation, abnormal Q maps appeared; (2) right ventricular MI, posterior wall MI and some lateral and apical MI are prone to miss abnormal Q potentials in the conventional 12-lead ECG; and (3) the MI location and relative size diagnosed through electrocardiographic peak mapping (EPM) correlated to acute MI in dog ventricles fairly well. The unexpected Q map reflections of right ventricular MI provide new clues for improving our automatic diagnosis system after further correlative studies. The results strongly support the feasibility of the application of EPM in clinical diagnosis.