Non-invasive foetal RHD genotyping via real-time PCR of foetal DNA from Chinese RhD-negative maternal plasma

BACKGROUND

A majority of studies predicting the foetal RhD blood group in free foetal DNA from RhD-negative maternal plasma have been conducted in Caucasian populations, whereas limited data have been accumulated for Asian populations. In this study, we assessed the feasibility of prenatal genotyping of RHD in RhD-negative Chinese pregnant women.

MATERIALS AND METHODS

Cell-free plasma DNA was extracted from 78 RhD-negative Chinese women carrying a singleton foetus (gestation between 14 and 40 weeks). Foetal DNA was confirmed by testing SRY or nine different polymorphic STR loci in the maternal plasma and buffy coat. Foetal RHD exons 5, 7 and 10 and intron 4 were successfully amplified with RQ-PCR. The RHD1227A allele was examined in all RhD-positive individuals. The foetal RHD genotyping results were compared with the infant cord blood serological analysis.

RESULTS

Among the 78 specimens, RHD genotyping results of 70 cases were in complete concordance with serological results from foetal umbilical cord blood. Sixty of these cases were identified as RhD-positive, and 10 cases were typed as RhD-negative. In addition, five cases were 'false-positives', while three cases were considered inconclusive. The detection rate was 89.7% (70/78). In four of the five 'false-positive' cases, the RhDel phenotype was assessed by detecting the RHD1227A allele. Thus, this method yielded a 94.9% (74/78) accuracy rate.

CONCLUSIONS

The correct foetal RhD phenotype may be accurately predicted from RhD-negative maternal plasma in Chinese subjects. The RHD1227A allele proved to be an important genetic marker in the RhDel Chinese population.

Formation mechanism of nanocrystalline high-pressure phases in silicon during nanogrinding

The phase transformations of Si under nanogrinding have been studied by transmission electron microscopy and Raman spectroscopy. Nanocrystalline high-pressure phases (Si-III/Si-XII) were found in the amorphous layer of the subsurface of heavily ground Si. The sequence of the phase transformation in nanogrinding has been found to be different to that in nanoindentation. The formation mechanism of the nanocrystalline high-pressure phases in nanogrinding is proposed based on experimental results.

[Construction of T-vectors for the direct, unidirectional cloning and analysis of PCR-amplified promoters]

The amplification and cloning of promoters are regularly employed procedures to study the mechanism of gene regulation. In the present study we developed a method to construct T-vectors used for the direct and unidirectional cloning and analysis of promoters. These so-called T-vectors pEGFP-T and pGL3-T were derived from their parent promoterless vectors pEGFP-1 and pGL3-basic, respectively. To construct the T-vectors, an AhdI recognition site within the Ampr gene in pGL3-basic was silent mutated using overlap extension PCR. Then, a specially designed AhdI cassette was cloned into the respective parent vectors. The procedures of the T-vector construction involved a strategy to minimize the background of nonrecombinant transformants and to eliminate reverse orientation of the PCR products into the T-vectors. The cloning efficiencies of the two T-vectors were both above 85% when tested with a PCR product amplified from a sequence that was pre-confirmed to be able to initiate transcription, and moreover, the constructs harbored the inserts in a desired orientation at a >90% rate. In transient transfection assays, we demonstrated these T-vectors are functional. Thus, the present study provides an easy method to construct a series of T-vectors used for promoter characterization.

Citrate exudation from white lupin induced by phosphorus deficiency differs from that induced by aluminum

Both phosphorus (P) deficiency and aluminum (Al) toxicity induce root exudation of carboxylates, but the relationship between these two effects is not fully understood. Here, carboxylate exudation induced by Al in Lupinus albus (white lupin) was characterized and compared with that induced by P deficiency. Aluminum treatments were applied to whole root systems or selected root zones of plants with limited (1 microM) or sufficient (50 microM) P supply. Aluminum stimulated citrate efflux after 1-2 h; this response was not mimicked by a similar trivalent cation, La(3+). P deficiency triggered citrate release from mature cluster roots, whereas Al stimulated citrate exudation from the 5- to 10-mm subapical root zones of lateral roots and from mature and senescent cluster roots. Al-induced citrate exudation was inhibited by P limitation at the seedling stage, but was stimulated at later growth stages. Citrate exudation was sensitive to anion-channel blockers. Al treatments did not affect primary root elongation, but inhibited the elongation of lateral roots. The data demonstrate differential patterns of citrate exudation in L. albus, depending on root zone, developmental stage, P nutritional status and Al stress. These findings are discussed in terms of possible functions and underlying mechanisms.

Three dimensional reconstruction of the pancreas based on the virtual Chinese human--female number 1

OBJECTIVE

To study the three dimensional (3D) reconstruction and 3D visualisation of the pancreas and create anatomy of the digitalised visual pancreas so as to construct a concrete basis for virtual operation and surgical operation on pancreas.

METHODS

The digital imaging data of pancreas, duodenum, common bile duct, arteries, and veins were obtained from the virtual Chinese human--female 1 (VCH-F1). The image data were investigated and 380 images ascertained of pancreas picked up from images numbers 2617 to 2996. Finally, the images from number 2574 to 3017 were adopted to segment and processed using ACDSee and Photoshop so as to reconstruct 3D pancreas digitally. The data of pancreatic surfaces were transformed into Visualization Toolkit (VTK). The GUI program written with VC+ was used to display this VTK file and realise 3D visualisation of the pancreas.

RESULTS

3D reconstruction and visualisation of the pancreas and the peri-pancreatic structures (the duodenum, the common bile duct,the inferior vena cava, the portal vein vessels, the aorta, the coeliac trunk vessels) was successful. The 3D and visualised pancreas manifested itself with its complete structure as well as its adjacency to other tissues.

CONCLUSION

The 3D reconstruction and 3D visualisation of the pancreas based on the digital data of VCH-F1 produces a digitally visualised pancreas, which promises a novel method for virtual operation on the pancreas, clinical operation on the pancreas, and anatomy of 3D visualised pancreas.

Screening and expression analysis of Phytophthora infestans induced genes in potato leaves with horizontal resistance

Horizontal resistance to late blight with quantitative and durable characteristics is a major objective for potato breeding programs. With the aim of investigating the molecular aspects of horizontal resistance, a cDNA microarray was used to identify Phytophthora infestans-induced genes from 100 expressed sequence tags (ESTs) selected from a subtractive cDNA library. Of the 100 cDNA clones represented on the array, 76 were differentially expressed in infected plants as compared with mock-inoculated control plants. Four groups of genes could be identified according to their expression patterns at three time points, 24, 48 and 72 h postinoculation (hpi). Group A appeared to be strongly induced (>10-fold) at 72 hpi. Group B demonstrated up-regulated expression patterns at all the three time points. The transcripts of group C peaked at 48 hpi, while genes of group D were up-regulated at 24 hpi and decreased slightly thereafter. Blast algorithm searches revealed that the largest set of up-regulated genes (about 35%) was assigned to the primary/secondary metabolism. Other genes with known or putative functions included disease defense or cell rescue (about 18%), transcription, signal transduction, cellular transporter/transport facilitation, development, protein synthesis/destination, as well as those playing roles in cellular organization. Furthermore, 15 genes encoding unknown function proteins were also identified. The results indicated that multiple defense mechanisms are involved in horizontal potato resistance to late blight and alteration in metabolic pathways is one of the most important defense responses.

Parathyroid hormone regulates osterix and Runx2 mRNA expression predominantly through protein kinase A signaling in osteoblast-like cells

Runt-related transcription factor 2 (Runx2) and osterix are osteoblast-specific transcription factors essential for the development of osteoblastic cells and bone formation. PTH given intermittently has anabolic effects on bone; however, the exact role remains to be understood completely. The purpose of this study was both to investigate whether PTH regulates Runx2 as well as osterix expression and to identify the signaling used. Using RT-PCR, we confirmed that PTH (1-34) regulated Runx2 and osterix mRNA expression, in rat osteoblast-like cell line UMR 106, in a dose- and time-dependent manner. PTH in low concentrations stimulated both Runx2 and osterix mRNA expression while that in high concentrations did not. Forskolin, an adenylate cyclase activator, also enhanced Runx2 and osterix transcription, and the stimulatory effects of PTH and forskolin were blocked by the pre-treatment of the cells with H-89, a protein kinase A (PKA) inhibitor. In contrast, the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) had no effect on Runx2 transcription, but induced an increase in osterix mRNA level at the concentration of 500 nM at 12 h after treatment. Moreover, pre-treatment of the cells with calphostin C, a PKC-specific inhibitor, reduced the increase in osterix transcripts enhanced by PTH and PMA 12 h after treatment. However, these inhibitory effects were not sustained for longer terms. These observations demonstrate that PTH stimulates Runx2 and osterix expression in vitro, at least in part, at transcriptional level. Induction of Runx2 mRNA is mediated through the activation of cAMP/PKA signal transduction. In the case of osterix, although the increase in mRNA level is predominantly mediated via cAMP/PKA signaling, PKC activation might also be involved in this process.

Antibody response to four secretory proteins from Mycobacterium tuberculosis and their complex antigen in TB patients

OBJECTIVE

To evaluate antibody responses to a panel of four protein antigens secreted from Mycobacterium tuberculosis, CFP-21, ESAT-6, MPT-63 and MPT-64, and their complex antigen.

DESIGN

Seventy-eight samples of serum and cerebral spinal fluid were tested by ELISA.

RESULTS

Serum IgM antibody positive rates of protein antigens CFP-21, ESAT-6, MPT-63 and MPT-64 and their multi-antigen complex were respectively 34.6%, 60.3%, 52.6%, 78.2% and 96.2%; IgG antibody positive rates were respectively 46.2%, 64.1%, 93.6%, 57.7% and 84.6%. The specificity of the antibodies to the four proteins secreted from M. tuberculosis and its mixture antigen was 100%; sensitivity to the multi-antigen complex was higher than for the four single antigens. Among the IgM positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6, MPT-63 and MPT-64 were significant (P < 0.01); among the IgG positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6 and MPT-64 were significant (P < 0.01). Although the IgG positive rate for MPT-63 was higher than for the multi-antigen complex, the difference was not significantly different (P > 0.05).

CONCLUSION

These findings indicate that the multi-antigen complex composed of CFP-21, ESAT-6, MPT-63 and MPT-64 may be useful in the diagnosis of TB.

Local atomic structures of palladium nanowire

In this paper, investigation of the structure of palladium nanowire has been performed by using genetic algorithm simulation based on the molecular dynamics. Our calculation employs a well-fitted, tight-binding many-body potential for Pd atoms. Some local atomic structures and defects in nanowires have been reported. The melting behavior of palladium nanowire has also been investigated. An interesting result is that the diffusion of the central atoms results in the beginning of the melting. The moving central atoms build up a monostrand atomic chain during the melting process. The single atomic chain is very stable which can exist in a wide temperature region (800-950 K). The formation of the single atomic chain causes some new defects in the nanowire. And the new defects result in the decrease of the thermal stability of the nanowire. Interestingly, the liquid from the nanowire melting has a supercooled feature because the splitting of the second peak of pair correlation function is observed. The curves of the internal energy and the local cluster are used to monitor the phase transition. The melting of the nanowire is not only due to the single atomic diffusion, but also the diffusion of the local clusters.

Melting behavior of one-dimensional zirconium nanowire

In this paper, we analyze the melting behavior of zirconium nanowire using the results of a series of molecular dynamics simulations. Our calculation employs a well-fitted, tight-binding many-body potential for zirconium atoms. The melting point of the nanowire is predicted by the root-mean-square displacements for inner and outer shells. Our simulations predict two melting behaviors: one is the inner melting and the other is the outer melting. Our results reveal that the melting of nanowire starts from the inner shell atoms. The melting point of zirconium nanowire is lower than the bulk value (2125 K). Moreover, the melting point of the inner shell is lower than that of the outer shell. A coexistence of crystal and liquid units is observed in the melting process of nanowire. An investigation of local clusters is carried out to further analyze the melting mechanism of the nanowire. The presence of the local clusters 1331, 1321, 1211, etc. is an indication of disordered structures. The pair and angular correlation functions are also presented for the analysis of the melting behavior. It is not only the diffusion of single atom but the diffusion of clusters result in the occurrence of the melting.

[Investigation of anti-Toxoplasma gondii antibodies in immunodeficient patients]

OBJECTIVE

To investigate the presence of anti-Taxoplasma gondii antibodies in immunodeficient patients.

METHODS

T. gondii-specific immunoglobulin G (IgG) antibodies in serum samples from 371 immunodeficient patients were detected by enzyme-linked immunosorbent assay (ELISA). The patients were with solid malignancies (including untreated digestive system malignancies and solid malignancies received chemotherapy), chronic liver diseases, patients received immunosuppressant therapy (dermatomyositis, psoriasis, pemphigus, post-renal transplantation, systemic lupus erythematosus and other miscellanies), lymphoma, leukemia and diabetes. 100 normal serum samples served as controls.

RESULTS

The positive rate of patients with solid malignancies received chemotherapy, solid malignancies received chemotherapy, chronic liver diseases, systemic lupus erythematosus and leukemia was 19.0%, 33.3%, 16.5%, 45.4% and 20.0%, respectively, being significantly higher than that of the control group(P < 0.05).

CONCLUSION

The immunosuppressed patients are highly predisposing to secondary T. gondii infection.

Phase I clinical trial of oral furtulon and combined hepatic arterial chemoembolization and radiotherapy in unresectable primary liver cancers, including clinicopathologic study

Surgical resection has been accepted as the only curative therapy for primary liver cancer (PLC). Unfortunately, most patients are surgically unresectable when they seek treatment. An alternative therapeutic approach for some of these patients is transcatheter arterial chemoembolization. However, this is not curative by itself, and additional therapy is required to eradicate residual disease. This study investigates the approach of preoperative hepatic arterial chemoembolization followed by the combination of oral Furtulon (5'-deoxy-5-fluorouridine) as a radiosensitizer and external beam radiotherapy (RT). From July 1997 to December 1998, 25 patients with unresectable PLC were treated with hepatic arterial chemoembolization followed by limited-field radiotherapy plus oral Furtulon as a radiosensitizer. Hepatic arterial chemoembolization was performed with 5-fluorouracil 1 g, cisplatin 80 mg (DDP), mitomycin C (MMC) 10 mg, and arterial embolization with iodized oil-10 ml mixed with 10 mg MMC. Hepatic arterial chemoembolization was performed at regular intervals of 6 weeks, and the patients then received limited-field RT. Mean tumor dose was 4,600 cGy (range, 4,100-5,200 cGy) in daily 1.8-Gy fractions, 5 times a week. The toxicity and responses between RT and surgery were assessed. After surgical evaluation, resection was performed. The histopathologic study was also performed in the specimens of both normal and radiation-injured liver tissues from the patients who underwent resection. Seventeen of 25 patients (68%) showed an objective response. One patient with cholangiocarcinoma involving the portal lymph nodes attained a complete response. Eight patients (32%) underwent sequential resection. The most common toxicity was an increase in liver enzymes, which were less than twofold of the upper limit of normal. Follow-up computed tomography studies after treatment showed a low-attenuation area adjacent to the hepatic tumor in the target volume. On pathologic evaluation, the low-attenuation area revealed hyperemia, distended hepatic sinusoids packed with erythrocytes, and hepatic cell loss when examined with microscopy; "new-born" hepatocytes, hepatic cords in the process of forming, and endothelial cells have appeared on electronic microscopic examination. The combination of hepatic arterial chemoembolization and external radiotherapy is efficacious and a safe modality for unresectable primary liver cancers. Furtulon offers the potential for use as a clinical radiosensitizer. Radiation can significantly damage the liver tissue between 41 Gy and 52 Gy, but the new hepatocytes were forming within the radiation-injured liver after RT.

Changes in ganglioside contents, plasma sialic acid and cAMP levels in experimental hepatoma in mice

The present study was designed to assess whether changes in glycolipids and cyclic AMP contents might serve as markers for the diagnosis of malignancy in the liver. The experimental model was a transplantable murine hepatoma. Experimental mice were divided into three groups: (1) a therapeutic group, which had been transplanted with hepatoma and treated with the antimetabolism drug 5-fluorouracil (0.2 mg/day i.p.), (2) a control group, which had been transplanted with hepatoma and treated with 0.2 ml 0.9% NaCl/day and (3) a normal group of mice. The ganglioside and cAMP contents in the hepatoma tissue, plasma cAMP, total- and lipid-bound sialic acid levels and red blood cell membrane sialic acid levels were determined. Results showed that the ganglioside content, total and lipid-bound sialic acid levels in the control group were significantly higher than those in the livers of normal mice (p < 0.01) while these respective values in the therapeutic group were significantly lower than those in the control group (p < 0.01). The cAMP levels of tumor tissues and plasma in the control group were lower than those in normal mice. No significant difference in red blood cell membrane sialic acid content was observed between the therapeutic and control groups though levels for both were higher than those in normal mice. These results indicate that ganglioside content and sialic acid levels in hepatoma tissues were significantly elevated, and cAMP levels in hepatoma tissues were significantly decreased during proliferation and abnormal differentiation.

[Diagnosis of nasal sinus fractures and its emergency management: 70 cases report]

OBJECTIVE

To study and improve the diagnosis and treatment level of nasal sinus fractures in the emergency.

METHOD

70 patients suffered from nasal sinus fractures were classified by degree of lesion. Partial of them (24 cases) were treated by Caldwell-Luc method and endoscopic sinus surgery for reducing fractures.

RESULT

The results of 22 out of 24 cases were satisfied and the other 2 good.

CONCLUSION

To better diagnose, one must pay attention to the symptoms of eyes, orbital floor and nasoethmoid sinus fracture and other severe injuries, CT scan is also necessary for diagnosis.

T (Thomsen-Friedenreich) and Tn epitope location and their spatial relations to adhesion plaques on human breast carcinoma cells: immunogold-silver staining studies at scanning electron microscopic level

T and Tn are pancarcinoma epitopes (EPs) which can be immunodetected in about 90% of adenocarcinomas (CAs). To study the location of T and Tn EPs and their relations to adhesion plaques on CA cells, immunogold-silver staining method was employed at scanning electron microscope (SEM) level. Human breast CA cells grown on coverslips were fixed in paraformaldehyde and glutaraldehyde, reacted with cocktails of monoclonal antibodies against T or Tn EPs, followed by incubation with 10 nm gold conjugated goat anti-mouse immuno-globulins. The positive gold particle labelling was amplified with silver enhancement solution, and the specimens were then routinely critical point dried, sputter-coated with palladium and observed under SEM. The studies show that T and Tn EPs are not randomly distributed on CA cell surface; they are aggregated at the adhesion plaque area. These results confirm that T and Tn EPs play roles in CA cell adhesion, and suggest that they may represent the initial points of contact by immuno-effectors and therefore can be utilized in immunointervention and anti-adhesion therapy against CA.

Quantitative computerized image analysis of Tn and T (Thomsen-Friedenreich) epitopes in prognostication of human breast carcinoma

The precursors of the blood group N and M-immunodominant structures, Tn and T (Thomsen-Friedenreich) epitopes (EPs) occur in approximately 90% of carcinomas (CAs) but are masked in benign-diseased and healthy tissues. We determined quantitatively on 55 primary invasive ductal breast CAs, stages I to IV, the prognostic value of extent of Tn and T EP expression over an observation period exceeding 5 years postoperatively. Classical, established pathological and histological prognostic characteristic indicators associated with survival were subdivided by standard criteria into favorable and unfavorable categories. Tissue sections were reacted with monoclonal anti-Tn and -T antibodies, followed by the streptavidin-biotin-peroxidase-DAB procedure; counterstain was methyl green. Tn and T EPs were then quantitated by computerized image analysis. Of the 55 CAs, 51 clearly expressed Tn and T, and four had traces. Strong Tn EP expression was statistically significantly associated with shortened 5-year disease-free interval, increasing pTNM stages, positive lymph node status, and increasing combined histological grades. T EPs were usually well expressed but showed no significant association with prognostic factors. Our results suggest that quantitative immunohistochemistry-image analysis of Tn EPs of primary breast CAs may add new parameters to prognostication.

Concurrent immunohistochemical staining of tumor-infiltrating lymphocytes and carcinoma-associated T (Thomsen-Friedenreich)/Tn antigens in human breast carcinoma

The composition of tumor-infiltrating lymphocytes (TIL) often reflects the host's immune response to the tumor. To study the relationship of TIL and carcinoma-associated T/Tn antigens in breast carcinoma, a straightforward concurrent immunoenzyme staining procedure was developed. Fresh tissue was directly fixed in a zinc-based fixative to preserve lymphocyte markers and then routinely embedded in paraffin. The TIL subtypes in the sections were identified in the first immunostaining cycle by reaction with a monoclonal antibody (MAb) to lymphocyte markers CD3, CD4, CD8, CD19, or CD56, followed by a modified avidin-biotin procedure and diaminobenzidine tetrahydrochloride-H2O2 for color development. This was followed by paraformaldehyde fixation to block antibody crossreactivity. The T and Tn antigens on carcinoma cells were then demonstrated in a second staining cycle by reaction with an MAb against T or Tn antigen, followed by an indirect immunoalkaline phosphatase procedure and corresponding substrate systems for color development. The distinguishable brown color for TIL and blue or red color for T or Tn antigen enabled us to identify the TIL subsets and to describe their relations with T/Tn antigen expression in situ. This approach may contribute to better understanding of the patients' immune defenses against their tumor and aid in prognostication.

Effect of supernatant of peripheral blood mononuclear cells from nephrotic patients on the sulfated compound synthesis by cultured glomerular epithelial cell

To identify the role of circulating immune factor(s) in the development of proteinuria, the supernatant of peripheral blood mononuclear cells (PBMC) were obtained from 15 patients with steroid-responsive nephrotic syndrome, and its effect on the synthesis of sulfated compound by cultured rat glomerular epithelial cell (GEC) were studied by 35S, 3H-leucine dual-isotope labelling technique. The result showed that the supernatant of PBMC from 9 patients without steroid treatment increased 35S uptake in GEC (P < 0.01), while there was no significant difference in 35S uptake between the 6 patients treated with prednisone (1.5-2.0 mg/kg.d-1) and 6 normal controls.

Increased production of interleukin 4 in children with simple idiopathic nephrotic syndrome

Sera and peripheral blood mononuclear cells (PBMC) were collected from 42 children with simple idiopathic nephrotic syndrome (INS) aged from 1.5 to 14 years and 28 age and sex-matched healthy children. The levels of IgE in serum and interleukin 4 (IL-4) in supernatant of PHA-activated PBMC were tested by ELISA. A significantly high incidence of allergic diseases was noted in INS children and their first-degree relatives, and there was a close association between atopy and INS. Besides, the levels of IgE and IL-4 were increased in nephrotic state (P < 0.001 both). IgE normal and IL-4 slightly lower in remission state (P < 0.2, P < 0.01 respectively). A positive correlation was noticed between IL-4 and IgE, and between IL-4 and 24-hour proteinuria (r = 0.472, r = 0.562; P < 005, P < 0.01 respectively). These showed a close association between atopy and INS. Both IL-4 and IgE, the important mediators in atopy, showed abnormal change in patients. The increased IL-4 production of T cells might account for the elevated serum IgE level. IL-4 may have a pathogenetic role in INS, but it still remains speculative.

[An experimental study of treatment with superoxide dismutase for alkali burn in the anterior segment of the rabbit eye]

The level of malondialdehyde (MDA) increased and the activity of superoxide dismutase (SOD) decreased significantly in the aqueous humor 4, 24, and 72 hours after alkali burn in the anterior segment of the rabbit eye. The level of MDA decreased and the activity of SOD increased significantly after subconjunctival injection of exogenous SOD, and the two were negatively correlated. The results suggest that alkali burn causes disturbances in reaction to free radicals, which may be controlled by an early supply of exogenous SOD.

Characterization of a gamma-glutamyl transpeptidase positive subpopulation of endothelial cells in a spontaneous tube-forming clone of rat cerebral resistance-vessel endothelium

A spontaneous tube-forming clone of rat cerebral resistance-vessel endothelium was characterized in long-term serial culture. In this study, a clone, RV-150 ECT, of cerebral resistance vessel endothelial cells in long-term culture has been shown to have a subpopulation of gamma-GTP positive cells that are present in all cultures regardless of confluency status or tube-forming stages. In pre-confluent and confluent cultures, the gamma-GTP positive cells are few in number, stain weakly, and are randomly distributed in the monolayers. In monolayer post-confluent cultures, gamma-GTP positive cells increase in number, stain strongly, and begin to show signs of non-random distributions. In early post-confluent cultures that have become a mixture of monolayer and multilayer cells, there is a further increase in gamma-GTP positive cells which begin to form distinct groupings. In mid post-confluent cultures, the multilayered areas of the culture have begun clustering to form clear multicellular aggregates. The gamma-GTP positive cells at this stage are reduced in number and are predominantly associated with the cell clusters. In late post-confluent cultures, the multicellular clusters develop clear cell cords between/among the clusters. At this stage the gamma-GTP positive cells are associated exclusively with cell clusters. With cord development, the gamma-GTP positive cells are associated with both clusters and cords, and are reduced in number apparently because of selective degeneration of these cells. The results of this study demonstrate that a phenotypically distinct subpopulation of endothelial cells exhibits characteristic features of the blood-brain barrier, namely gamma-GTP. The ability of these cells to express this property in long-term serial culture suggests that this may represent a useful in vitro model to study the growth and differentiation of blood-brain barrier vessels.

Structure, sequence and expression of the mouse Cx43 gene encoding connexin 43

Gap junctions, membrane channels that mediate the diffusion of ions and small molecules between cells, are hypothesized to play a role in development and growth regulation. The Cx43 gene (encoding connexin 43) is one member of the gap junction gene family whose transcripts are expressed in a highly regionalized manner during mouse development. We cloned and sequenced Cx43 cDNAs from a 7.5-day mouse embryo cDNA library. These cDNA clones encode the authentic 43-kDa connexin. Analysis of RNA isolated from different regions of the 7.5-day mouse embryo revealed that Cx43 transcripts are differentially expressed, with expression detected in the embryo proper, but not in the extraembryonic region containing the ectoplacental cone. Using one of the newly isolated mouse Cx43 cDNA probes, we screened a mouse genomic DNA library and cloned the Cx43 gene. Restriction mapping and sequencing of the cloned genomic inserts revealed that Cx43 contains two exons and a 10.5-kb intron located in the 5' untranslated region (5'-UTR). We mapped the Cx43 transcription start point (tsp) by RNase protection and primer extension analyses and showed that transcripts expressed in the 7.5-day mouse embryo and in adult tissues are initiated from the same tsp. The DNA sequence immediately upstream from the tsp contains a putative AP1-binding site and a degenerate TATA consensus sequence. A comparison of mouse, rat, human and bovine Cx43s showed that the 3'-UTR has an unexpectedly high degree of sequence homology. This includes conservation of four AUUUA motifs, a sequence associated with transcript instability in immediate early genes.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin D and calcium metabolism in children with nephrotic syndrome of normal renal function

This study demonstrates that there are distinct abnormalities of vitamin D and calcium metabolism in children with nephrotic syndrome (NS) and normal renal function. In patients with active NS, serum calcium, ionized calcium, 25-OHD3 and CT were decreased, plasma PTH level was increased and serum ALP was elevated. These abnormalities returned to normal in remission. Serum 1,25-(OH)2D3, although normal in absolute value during both active and remission stage, may be inappropriately low for the hypocalcemia and hyperparathyroidism during the active stage. Therefore, children with active NS are at the risk of developing metabolic bone disease. The treatment with a high dose of vitamin D3 may correct the abnormalities, which suggests vitamin D3 should be used in children with protracted active NS.

Phagocytosis of immunoglobulin G and C3-bound human sperm by human polymorphonuclear leukocytes is not associated with the release of oxidative radicals

Antisperm antibody (ASA)- and complement (C)-mediated immune injury to human sperm is thought to be caused in part by phagocytic neutrophils. To investigate this process, we co-cultured purified human polymorphonuclear leukocytes (PMN) with swim-up sperm in the presence of ASA-positive and ASA-negative sera and assayed for PMN respiratory burst activity, monitored by the release of superoxide anion (O2-) and hydrogen peroxide (H2O2). Phorbol myristate acetate (PMA) and opsonized zymosan were used as positive controls. Phagocytosis of ASA-positive and C-bound sperm by PMN did not enhance O2- production when compared to incubation of sperm with ASA-negative sera. Phagocytosis of ASA-positive and C-bound sperm also resulted in minimal release of H2O2 when compared with ASA-positive and C-negative sperm that were not phagocytosed. In contrast, PMN were maximally stimulated to release O2- in response to either opsonized zymosan or PMA. The kinetics of PMA-induced O2- release was unaffected by the presence of ASA-positive and C-bound sperm. Cytocentrifuge preparations of PMN incubated with ASA-positive and C-bound sperm revealed limited O2- release at the site of PMN/sperm contact. These results indicated that 1) phagocytosis of motile sperm by PMN requires the binding of both ASA and C to the sperm surface; 2) phagocytosis of ASA-positive and C-positive sperm by PMN fails to release reactive oxygen species; and 3) metabolic processes associated with PMN respiratory burst activity may not be coupled to the ingestion of ASA-positive and C-bound sperm.

Density-dependent regulation of cell surface ?-glutamyl transpeptidase in cultured glial cells

A decline in cell surface gamma-glutamyl transpeptidase specific activity was previously observed to be concomitant with C6 glial cell proliferation. To elucidate the underlying factor(s) mediating gamma-glutamyl transpeptidase down-regulation, the effects of C6 cell density and culture conditions on cell surface transpeptidase activity levels were investigated. After 24 h of culture, the transpeptidase specific activities were inversely related to the initial plating densities. The lower-density cultures showed an induction within 24 h of plating. As the cultures proliferated, the specific transpeptidase activities declined to a common low level at post-confluency. The gamma-glutamyl transpeptidase down-regulation was unrelated to cell growth rate and was most pronounced during logarithmic proliferation. Induction and down-regulation of gamma-glutamyl transpeptidase activity at low cell densities were not a result of trypsinization. Supplementation of low-density cultures with conditioned medium, use of matrix-coated wells, or periodic replacement of growth media to prevent conditioning had minor effects on the decline of cell surface activity. Kinetic analysis showed that the Michaelis constants and the reaction mechanism were unaltered by cell density, indicating that down-regulation was not due to allosteric factors or an alteration in enzyme character. A reduction in the maximal velocity of cell surface transpeptidation at higher cell densities suggested that gamma-glutamyl transpeptidase down-regulation is related to the concentration of enzyme at the cell surface. Immunocytochemical localization of gamma-glutamyl transpeptidase demonstrated that gamma-glutamyl transpeptidase antigen levels decrease as C6 cell density increases. These results led us to propose that cell-cell contact stimulates the disappearance of gamma-glutamyl transpeptidase from the surface of cultured C6 glial cells.