Standard treatment for Helicobacter pylori infection is suboptimal in non-ulcer dyspepsia compared with duodenal ulcer in Chinese

BACKGROUND

Recent studies suggest that the Helicobacter pylori eradication rate in patients with non-ulcer dyspepsia is lower when compared to patients with peptic ulcer diseases.

AIM

The aim of this study was to study the efficacy of triple therapy for H. pylori infection in patients with duodenal ulcer vs. patients with non-ulcer dyspepsia.

METHODS

A total of 582 Chinese patients with proven H. pylori infection were recruited to receive: omeprazole 20 mg, amoxicillin 1000 mg and clarithromycin 500 mg all given twice daily for 7 days (OCA regime). Endoscopy with rapid urease test, histology and culture were performed before treatment. Post-treatment H. pylori status was determined by (13)C-urea breath test. Metronidazole, clarithromycin and amoxicillin resistance was defined as minimum inhibitory concentration (MIC) of >8 microg/mL, >1 microg/mL and >1 microg/mL, respectively.

RESULTS

A significantly higher (intention-to-treat/per-protocol) eradication rate was found in patients with duodenal ulcer than those with non-ulcer dyspepsia (91/94% vs. 84/88% respectively, P = 0.011 and P = 0.016). Clarithromycin resistance rate was higher in patients with non-ulcer dyspepsia than those with duodenal ulcer (14% vs. 6%, P = 0.015). Clarithromycin resistance (40% vs. 5%, P < 0.001, OR 12, 95% CI: 5.7-24.3) and the diagnosis of non-ulcer dyspepsia (91% vs. 84%, P = 0.011, OR 2.0, 95% CI: 1.2-3.3) significantly affected the success of H. pylori eradication.

CONCLUSION

Clarithromycin resistance accounts for the significantly lower and suboptimal H. pylori eradication rate of OCA regimen in Chinese patients with non-ulcer dyspepsia compared to those with duodenal ulcer.

Family size, miscarriage-proneness, and handedness: tests of hypotheses of the developmental instability theory of handedness

The handedness theory of Yeo and Gangestad (1993) posits that moderate right-handedness is the modal manifestation of genetic handedness and that ''developmental instability'' produces deviations from modal handedness. It is also suggested (1) that sinistral parents may produce fewer offspring than do dextral parents; and (2) that sinistral mothers may be more prone to miscarriages than are dextral mothers. In line with these hypotheses, Gangestad et al. (1996) reported that a human leukocyte antigen (B8) was related to both left-handedness and to reduced offspring number in their study. They also found that left-handedness was related to the human leukocyte antigen DR3, and Yeo and Gangestad (1998) noted that this antigen has been found by Christiansen et al. (1996) to be associated with an increased risk of spontaneous abortion in women. We assessed the first hypothesis through a study of the family sizes of 2083 families with two right-handed parents and 502 families having one or more left-handed parents; we assessed the second hypothesis from miscarriage history data supplied by 300 dextral and 52 sinistral mothers. Results supported the developmental instability theory with respect to the hypothesis regarding family size, but not with respect to the hypothesis regarding miscarriage-proneness.

Naturopathic and Western herbal medicine practice in Australia-a workforce survey

BACKGROUND

Despite substantial growth in the use of complementary medicine, no comprehensive national study has been undertaken of the naturopathic and Western herbal medicine component of the healthcare workforce in Australia. This study aimed to examine the nature of these practices and this currently unregulated workforce in Australia.

METHODS

A comprehensive survey questionnaire was developed in consultation with the profession and distributed nationally to all members of the naturopathic and Western herbal medicine workforce.

RESULTS

The practices of herbal medicine and naturopathy make up a sizeable component of the Australian healthcare sector, with approximately 1.9 million consultations annually and an estimated turnover of $AUD 85 million in consultations (excluding the cost of medicines). A large proportion of patients are referred to practitioners by word of mouth. Up to one third of practitioners work in multidisciplinary clinics with other registered sectors of the healthcare community. The number of adverse events associated with herbal medicines, nutritional substances and homoeopathic medicines recorded in Australia is substantial and the types of events reported are not trivial. Data suggest that practitioners will experience one adverse event every 11 months of full-time practice, with 2.3 adverse events for every 1000 consultations (excluding mild gastrointestinal effects).

CONCLUSION

These data confirm the considerable degree of utilisation of naturopathic and Western herbal medicine practitioners by the Australian public. However, there is a need to examine whether statutory regulation of practitioners of naturopathy and Western herbal medicine is required to better protect the public.

Effects of copper sulfate on ion balance and growth in tilapia larvae (Oreochromis mossambicus)

Newly hatched tilapia larvae were exposed to sublethal concentrations of Cu2+ (0, 30, 50, and 100 microg/L) and lethal concentrations of Cu2+ (200 and 400 microg/L) for 24-96 h. The interaction of the exposure dose and time was related to the Cu2+ accumulation rate, which showed a higher accumulation rate with sublethal concentrations of Cu2+ within 24 h compared to the other treatments. Furthermore, Cu2+ contents in the whole body of larvae significantly increased following Cu2+ exposure times up to 96 h. Cu2+ in the medium produced a dose-response effect on Na+ and K+ contents in larvae after 96 h of exposure time. Changes in Ca2+ contents statistically significantly decreased and were shown to be dose-responsive for larval exposure times exceeding 72 h. Changes of Ca2+ contents were more sensitive than those of Na+ and K+ with Cu2+ treatment of early larvae. Notably Na+ and K+ contents showed significant increases of 17-23% in larvae exposed to low concentrations of Cu2+ (30-50 microg/L) for 24-72 h as compared to control larvae. Cu2+ caused no significant effect on body Cl- content or osmolality except at 100 microg/L Cu2+ for 24 h in tilapia larvae as compared to the control. However, there was a restoration phenomenon in larvae exposed to 100 microg/L Cu2+ for longer than 72 h. The water content of larvae exposed to Cu2+ for 96 h significantly decreased. The yolk absorption rate of tilapia larvae was significantly suppressed when they were exposed to Cu2+ medium containing 30, 50, 100, 200, or 400 Cu2+ microg/L from 72 h post transfer. These results obviously show that larvae are sensitive to Cu2+ during early development.

Protoporphyrin IX production and its photodynamic effects on glioma cells, neuroblastoma cells and normal cerebellar granule cells in vitro with 5-aminolevulinic acid and its hexylester

5-Aminolevulinic acid (ALA) has shown promising in photodynamic detection and therapy of brain tumor. However, the knowledge on selective accumulation of ALA-induced protoporphyrin IX (PpIX) in brain tumor tissue is still fragment. In the present study, the rat C6 glioma cells, human SK-N-SH neuroblastoma cells, and rat normal cerebellar granule cells (RCG) were used to investigate the PpIX production and photocytotoxicity in vitro. The C6 cells and SK-N-SH cells showed a similar kinetics of PpIX accumulation after exposure to ALA or ALA hexyl ester (ALA-H), with an initial increase up to 6-8 h and then saturated. In the case of RCG cells, the PpIX accumulation slowly increased until 12 h studied. However the cellular PpIX content was more than 10 times higher in the C6 and SK-N-SH cells than that in the normal RCG cells. The intracellular localization of PpIX measured by cofocal laser scanning microscopy was in same pattern in the C6 glioma cells and RCG normal cells with a diffuse cytoplasm distribution. The sensitivity of the C6 cells and SK-N-SH cells to ALA or ALA-H PDT was similar. It appears that ALA-H could achieve similar or slightly better results than ALA with respect to PpIX production and photoinactivation of cells, although a 10 times lower concentration of ALA-H was used.

Identification and expression of human CD81 gene on murine NIH/3T3 cell membrane

The human CD81 (hCD81) molecule has been identified as a putative receptor for hepatitis C virus (HCV). In this study, eukaryotic expression vector pCDM8-hCD81 containing hCD81 cDNA and pSV2neo helper plasmid was used to cotransfect with lipofectamine into murine fibroblast cell line NIH/3T3 to establish an hCD81-expressing cell line. Resistant cell clones were obtained 20 days after the selection with neomycin (600 micro/ml) and then cultured as monoclones. The expression of the transfected hCD81 gene in the cells was verified by RT-PCR and flow cytometry analyses. One of the selected cell clones showed obvious expression of hCD81 and was named NIH/3T3-hCD81. Competitive inhibition tests indicated that the binding of monoclonal anti-hCD81 (JS-81) to NIH/3T3-hCD81 cells was inhibited by recombinant HCV E2 protein, suggesting that the expressed hCD81 molecules on NIH/3T3-hCD81 cells maintain natural conformation of binding to HCV E2. The transfected NIH/3T3-hCD81 cells should be of great potential value in studies on HCV attachment and onset of infection.

Non-invasive assessment of arterial distension waveforms using gradient-based hough transform and power Doppler ultrasound imaging

The peripheral arterial vessel often appears as an elliptic shape under the constraints of the surrounding tissues. In this study, the gradient-based Hough transform was used to detect the central location of the ellipse and the lumen area of the arterial vessel non-invasively using power Doppler imaging. Sequential ultrasound images were used to construct arterial distension waveforms in both the major- and minor-axis directions for a few cardiac cycles. The common carotid arteries (CCAs) for nine healthy male volunteers (mean age 24 years), in the sitting position, were investigated in vivo. The CCAs (n = 9) had a mean diameter of 5.83mm, and the pulsatile diameter distension was 13.7+/-1.9%. The brachial artery and dorsalis pedis artery for five healthy male volunteers (mean age 26 years), in the supine position, had mean diameters of 4.03mm and 2.83mm and distensions of 16.7+/-4.6% and 15.5+/-5.4%, respectively. The movement of the arterial centre location during the cardiac cycle reflected the asymmetry of the reaction forces produced by the surrounding soft tissues. The present method can obtain the response of vessel distension to pulse pressure, as well as the constrained conditions of the arteries.

Spectrum of mutations of the AAAS gene in Allgrove syndrome: lack of mutations in six kindreds with isolated resistance to corticotropin

Familial glucocorticoid deficiency due to corticotropin (ACTH) resistance consists of two distinct genetic syndromes that are both inherited as autosomal recessive traits: isolated ACTH resistance (iACTHR), which may be caused by inactivating mutations of the ACTH receptor (the MC2R gene) or mutations in an as yet unknown gene(s), and Allgrove syndrome (AS). The latter is also known as triple-A syndrome (MIM 231550). In three large cohorts of AS kindreds, the disease has been mapped to chromosome 12; most recently, mutations in the AAAS gene on 12q13 were found in these AS families. AAAS codes for the WD-repeat containing ALADIN (for alacrima-achalasia-adrenal insufficiency-neurologic disorder) protein. We investigated families with iACTHR (n = 4) and AS (n = 6) and a Bedouin family with ACTHR and a known defect of the TSH receptor. Four AS families were of mixed extraction from Puerto Rico (PR); most of the remaining six families were Caucasian families from North America (NA). Sequencing analysis found no MC2R genetic defects in any of the kindreds. No iACTHR kindreds, but all of AS families, had AAAS mutations. The previously reported IVS14+1G-->A splice donor mutation was found in all PR families, apparently due to a founder effect; one NA kindred was heterozygous for this mutation. In the latter family, long-range PCR failed to identify a deletion or other rearrangements of the AAAS gene. No other heterozygote or transmitting parent had any phenotype that could be considered part of AS. The IVS14+1G-->A mutation results in a premature termination of the predicted protein; although it was present in all PR families (in the homozygote state in three of them), there was substantial clinical variation between them. One PR family also carried a novel splice donor mutation of the AAAS gene in exon 11, IVS11+1G-->A; the proband was a compound heterozygote. A novel point mutation, 43C-->A(Gln15Lys), in exon 1 of the AAAS gene was identified in the homozygote state in a Canadian AS kindred with a milder AS phenotype. The predicted amino acid substitution in this family is located in a sequence that may participate in the preservation of stability of ALADIN beta-strands, whereas the splicing mutation in exon 11 may interfere with the formation of WD repeats in this molecule. We conclude that 1) AAAS does not appear to be frequently mutated in families with iACTHR; 2) AAAS is mutated in AS families from PR (that had previously been mapped to 12q13) and NA; and, 3) there is significant clinical variability between patients with the same AAAS defect.

AMPA-preferring receptors mediate excitatory non-NMDA responses of primate retinal ganglion cells

Glutamate and kainate-induced currents of primate ganglion cells were studied using the whole-cell patch-clamp technique in a retinal slice preparation. Antagonists and allosteric modulators of desensitization selective for either alpha-amino-3-hydroxy-5-methyl-4-isoazoleprionic acid (AMPA)- or kainate-preferring receptors were used to determine the contributions of each type of receptor to excitatory responses. With synaptic transmission and NMDA receptors blocked, the AMPA-preferring receptor antagonist GYKI 52466 (30 microM-100 microM) reversibly blocked most of the glutamate-induced current in ganglion cells. GYKI 52466 also blocked the response in ganglion cells to focally applied kainate, suggesting that the current response to kainate arises from activation of AMPA-preferring receptors, and not kainate-preferring receptors. Both cyclothiazide (10 microM-100 microM) and the novel drug 4-[2-(phenylsulfonylamino)ethylthio]-2,6-difluoro-phenoxyacetamide (PEPA, 20 microM-100 microM), which selectively enhance responses mediated by AMPA-preferring receptors, enhanced glutamate-induced responses of ganglion cells. Since these drugs preferentially inhibit desensitization of the flip and flop splice variants, respectively, of AMPA-preferring receptors, it is likely that both splice variants are present on these ganglion cells. Concanavalin A, which selectively suppresses the desensitization of kainate-preferring receptors, had no effect on the glutamate-induced responses of ganglion cells. We conclude that the non-NMDA component of the excitatory, glutamatergic input to primate ganglion cells is mediated largely by AMPA-preferring receptors, with little, if any, kainate-preferring receptor-mediated response.

Head-column field-amplified sample stacking in capillary electrophoresis for the determination of cimetidine, famotidine, nizatidine, and ranitidine-HCl in plasma

In this study, low concentrations of histamine2-receptor (H2-)antagonists were effected across a water plug, with separation taking place in a binary buffer comprising ethylene glycol and NaH2PO4 (pH 5.0), and detection at 214 nm. Liquid-liquid extraction with ethyl acetate- isopropanol is shown to provide extracts that are sufficiently clean. The calibration curves were linear over a concentration range of 0.1-2.00 microg/mL cimetidine, 0.2-5.0 microg/mL ranitidine-HCl, 0.3-5.0 microg/mL nizatidine, and 0.1-3.0 microg/mL famotidine. Mean recoveries were > 82%, while the intra- and interday relative standard deviations (RSDs) and relative errors (REs) were all < 13%. The method is sensitive with a detection limit of 3 ng/mL cimetidine, 30 ng/mL ranitidine HCl, 50 ng/mL nizatidine and 10 ng/mL famotidine (S/N = 3, electric-driven injection 90 s). This newly developed capillary electrophoresis (CE) method was applied for the determination of analytes extracted from plasma taken from a volunteer dosing a cimetidine, ranitidine, and nizatidine tablet simultaneously. These three H2-antagonists can be detected in real samples by this method, excluding the low dosing of famotidine tablet.

Simultaneous determination of cimetidine, famotidine, nizatidine, and ranitidine in tablets by capillary zone electrophoresis

A simple capillary zone electrophoresis (CZE) method is described for the simultaneous determination of cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine (RAN). The analysis of these drugs was performed in a 100 mM phosphate buffer, pH 3.5. Several parameters were studied, including wavelength for detection, concentration and pH of phosphate buffer, and separation voltage. The quantitative ranges were 100-1,000 microM for each analyte. The intra- and interday relative standard deviations (n = 5) were all less than 4%. The detection limits were found to be about 10 microM for CIM, 20 microM for RAN, 20 microM for NIZ, and 10 microM for FAM (S/N = 3, injection 1 s) at 214 nm. All recoveries were greater than 92%. Applications of the method to the assay of these drugs in tablets proved to be feasible.

alpha(2)-Macroglobulin from rheumatoid arthritis synovial fluid: functional analysis defines a role for oxidation in inflammation

A hallmark of inflammation is the release of oxidants, proteinases, and cytokines, all important mediators of the inflammatory cascade. alpha(2)-Macroglobulin (alpha(2)M) is a high-affinity, broad-specificity proteinase inhibitor that also binds and regulates the biological activities of a number of cytokines. We demonstrated recently that hypochlorite-oxidized alpha(2)M has decreased ability to inhibit proteinases and regulate cytokines in vitro. The role of oxidation in regulating alpha(2)M functions in vivo is largely unknown. To determine the extent and biological consequence of in vivo alpha(2)M oxidation, we measured the degree of oxidative alpha(2)M modification from rheumatoid arthritis (RA) synovial fluid and compared this with osteoarthritis (OA) as noninflammatory controls. We found that RA synovial fluid alpha(2)M is significantly more oxidized than that from OA. RA synovial fluid also contains a twofold higher median alpha(2)M level than OA, while having only half the alpha(2)M-proteinase inhibitory activity. Detailed biochemical analysis demonstrates proteolytically degraded alpha(2)M in RA greater than in OA synovial fluid. Additionally, the hypochlorite-mediated oxidation product, chlorotyrosine, is present in RA more than in OA or plasma alpha(2)M samples. Taken together, these findings confirm a role for oxidative regulation of inflammation by altering the functions of extracellular mediators such as alpha(2)M.

Differential regulation of the fibroblast growth factor (FGF) family by alpha(2)-macroglobulin: evidence for selective modulation of FGF-2-induced angiogenesis

The fibroblast growth factor (FGF) family has an important role in processes such as angiogenesis, wound healing, and development in which precise control of proteinase activity is important. The human plasma proteinase inhibitor alpha(2)-macroglobulin (alpha(2)M) regulates cellular growth by binding and modulating the activity of many cytokines and growth factors. These studies investigate the ability of native and activated alpha(2)M (alpha(2)M*) to bind to members of the FGF family. Both alpha(2)M and alpha(2)M* bind specifically and saturably to FGF-1, -2, -4, and -6, although the binding to alpha(2)M* is of significantly higher affinity. Neither alpha(2)M nor alpha(2)M* bind to FGF-5, -7, -9, or -10. FGF-2 was chosen for more extensive study in view of its important role in angiogenesis. It was demonstrated that FGF-2 binds to the previously identified TGF-beta binding site. The alpha(2)M* inhibits FGF-2-dependent fetal bovine heart endothelial cell proliferation in a dose-dependent manner. Unexpectedly, alpha(2)M* does not affect FGF-2-induced vascular tubule formation on Matrigel basement membrane matrix or collagen gels. Further studies demonstrate that FGF-2 partitions between fluid-phase alpha(2)M* and solid-phase Matrigel or collagen. These studies suggest that the ability of alpha(2)M* to modulate the activity of FGF-2 is dependent on an interplay with extracellular matrix components. (Blood. 2001;97:3450-3457)

Immunocytochemical analysis of cholinergic amacrine cells in the tiger salamander retina

Cholinergic amacrine cells in the tiger salamander retina were observed for the first time by using antibodies against choline acetyltransferase (ChAT). ChAT-immunoreactive cells were present in the inner nuclear layer (INL) and in the ganglion cell layer (GCL), and the somas of the former population (average diameter = 15.13 microm) were slightly smaller than those of the latter population (average diameter = 16.42 microm). The processes of these cells form two distinct narrow bands in the inner plexiform layer (IPL), one located near 0.2 inner plexiform units (IU) and the other near 0.65-0.7 IU. Soma size, cell density and spatial distribution of ChAT-positive cells were quantitatively analyzed. Our results suggest that cholinergic amacrine cells in the salamander retina are very similar to their counter parts in other species, and they can be used as a model system for studying cholinergic functions in the visual system.

Apoptotic cell death of cultured salamander photoreceptors induced by cccp: CsA-insensitive mitochondrial permeability transition

Photoreceptor degeneration is mediated by apoptosis in several animal models, although the underlying mechanisms are yet to be elucidated. We present here an apoptotic model based on a primary cell culture of tiger salamander photoreceptors, in which treatment with carbonyl cyanide m-chlorophenylhydrazone (cccp), a protonophore, induced apoptosis. Cells exposed to cccp showed condensed nuclei and displayed positive TdT-dUTP terminal nick-end labeling (TUNEL). In addition, 10–100 microM cccp rapidly induced a reduction of Delta psi(m) and &gt; or = 30 microM cccp induced a significant leakage of calcein from mitochondria to cytosol and nucleus, indicating a change in mitochondrial inner membrane permeability. Cyclosporin A (CsA), a transition pore blocker, did not prevent the cccp-induced MPT or the cccp-evoked apoptotic cell death, suggesting that cccp-induced apoptotic process was mediated by a CsA-insensitive pathway. This cell model provides an in vitro tool for studying mechanisms of photoreceptor apoptosis in isolated photoreceptors and may provide clues to the etiology of retinal degeneration.

Delta-aminolevulinate dehydratase polymorphism and blood lead levels in Chinese children

This study investigated the relationship between the delta-aminolevulinate dehydratase (ALAD) isozymes and the blood lead levels of Chinese children. The purpose of this study was to determine the precise ALAD genotyping in Chinese children and identify the contribution of the ALAD genotype to the body lead burden. Blood samples were obtained from 109 boys and 120 girls. These children were 6-10 years old and from a single primary school. Both the school and their homes were within a community in which a large smelter was located. An environmental questionnaire was obtained for each subject, and blood lead levels and ALAD isozyme phenotype were analyzed in a double-blinded fashion. The blood lead levels of 229 children ranged from 4.5 to 26.4 microg/dl; the mean was 10.3 microg/dl and the standard deviation was 3.3 microg/dl. The gene distribution of the ALAD isozyme phenotypes in these environmentally exposed children was ALAD 1-1 (92%), ALAD 1-2, (8%), and ALAD 2-2 (0%). The mean blood level of the environmentally exposed children, who were homozygous for the ALAD1 allele, was 9.7 microg/dl; the mean for those who were heterozygous for the ALAD2 allele was 11.7 microg/dl. Using the t test, the means of the groups were different at the level of t=2.2058, P<0.05. Step-wise regression and multiple analyses of covariance were employed to control the confounders to measuring the independent contribution of the ALAD genotype on blood lead levels. After controlling the confounders, the contribution of the ALAD genotype to the blood lead level was greater and still statistically significant (F=7.3201, P<0.01). These results indicate that individuals carrying the ALAD2 allele are more likely to have sustained increases in blood lead levels when exposed to a lead-contaminated environment.

Expression and characterization of the naturally occurring mutation L394R in human gamma-glutamyl carboxylase

Patients with mutation L394R in gamma-glutamyl carboxylase have a severe bleeding disorder because of decreased biological activities of all vitamin K-dependent coagulation proteins. Vitamin K administration partially corrects this deficiency. To characterize L394R, we purified recombinant mutant L394R and wild-type carboxylase expressed in baculovirus-infected insect cells. By kinetic studies, we analyzed the catalytic activity of mutant L394R and its binding to factor IX's propeptide and vitamin KH(2). Mutant L394R differs from its wild-type counterpart as follows: 1) 110-fold higher K(i) for Boc-mEEV, an active site-specific, competitive inhibitor of FLEEL; 2) 30-fold lower V(max)/K(m) toward the substrate FLEEL in the presence of the propeptide; 3) severely reduced activity toward FLEEL carboxylation in the absence of the propeptide; 4) 7-fold decreased affinity for the propeptide; 5) 9-fold higher K(m) for FIXproGla, a substrate containing the propeptide and the Gla domain of human factor IX; and 6) 5-fold higher K(m) for vitamin KH(2). The primary defect in mutant L394R appears to be in its glutamate-binding site. To a lesser degree, the propeptide and KH(2) binding properties are altered in the L394R mutant. Compared with its wild-type counterpart, the L394R mutant shows an augmented activation of FLEEL carboxylation by the propeptide.

The conformation-dependent interaction of alpha 2-macroglobulin with vascular endothelial growth factor. A novel mechanism of alpha 2-macroglobulin/growth factor binding

alpha(2)-Macroglobulin (alpha(2)M) is a highly conserved proteinase inhibitor present in human plasma at high concentration (2-4 mg/ml). alpha(2)M exists in two conformations, a native form and an activated, receptor-recognized form. While alpha(2)M binds to numerous cytokines and growth factors, in most cases, the nature of the alpha(2)M interaction with these factors is poorly understood. We examined in detail the interaction between alpha(2)M and vascular endothelial growth factor (VEGF) and found a novel and unexpected mechanism of interaction as demonstrated by the following observations: 1) the binding of VEGF to alpha(2)M occurs at a site distinct from the recently characterized growth factor binding site; 2) VEGF binds different forms of alpha(2)M with distinct spatial arrangement, namely to the interior of methylamine or ammonia-treated alpha(2)M and to the exterior of native and proteinase-converted alpha(2)M; and 3) VEGF (molecular mass approximately 40 kDa) can access the interior of receptor-recognized alpha(2)M in the absence of a proteinase trapped within the molecule. VEGF bound to receptor-recognized forms of alpha(2)M is internalized and degraded by macrophages via the alpha(2)M receptor, the low density lipoprotein receptor-related protein. Oxidation of both native and receptor-recognized alpha(2)M results in significant inhibition of VEGF binding. We also examined the biological significance of this interaction by studying the effect of alpha(2)M on VEGF-induced cell proliferation and VEGF-induced up-regulation of intracellular Ca(2+) levels. We demonstrate that under physiological conditions, alpha(2)M does not impact the ability of VEGF to induce cell proliferation or up-regulate Ca(2+).

Morphological and electrophysiological properties of dissociated primate retinal cells

Although isolated retinal cell preparations have been used widely to study retinal function in lower vertebrates, dissociated cells from primate retina have not been developed for routine physiological experiments. In this study, we demonstrated the feasibility of obtaining viable and identifiable dissociated cells from the primate retina. In addition, we characterized voltage-dependent membrane currents in each type of primate retinal cell with the whole-cell patch-clamp technique. Multiple types of ionic conductance with distinctive current profiles were recorded in various types of primate retinal neurons. Photoreceptors exhibited an inward I(H) activated by membrane hyperpolarization and an outward current activated at depolarized potentials. Two types of potassium currents (transient potassium current, I(K(A)), and delayed rectifier potassium current, I(K(V))) were recorded from bipolar cells. I(K(A)) dominated the current response in putative midget bipolar cells, and I(K(V)) was mainly associated with putative rod bipolar cells. L-type calcium currents (I(Ca)) were observed in primate bipolar cells with axon terminals, but not in axotomized bipolar cells. Large voltage-dependent sodium currents (I(Na)) were only recorded from ganglion cells. Muller cells exhibited I(K(V)) and large potassium inward rectifier current (I(K(IR))), and occasionally a small I(Na). Neurons with electrophysiological signatures of amacrine cells and horizontal cells were also studied even though their morphological features were lost during cell dissociation. By using both morphological and physiological criteria outlined in this report, it is possible to use the dissociated retinal cell preparation as an in vitro system for physiological, biochemical and pharmacological studies of the primate visual system.

Metallothionein induction in early larval stages of tilapia (Oreochromis mossambicus)

Amounts of whole-body metallothionein (MT) in tilapia (Oreochromis mossambicus) larvae increased to a peak (1,500 ng mg(-1) protein) 1 d after hatching (H1), decreased rapidly thereafter, and was maintained at a constant level (700 ng mg(-1)) 3 d after hatching (H3). Waterborne Cd(2+) could stimulate MT expression in newly hatched (H0) larvae in dose-dependent and time-dependent patterns. H0 larvae, which were treated with 35 microg L(-1) Cd(2+) for 24 h, showed a 1.7-fold increase in the MT amount (174.0+/-64.7) and a 6. 5-fold increase in accumulated Cd(2+) but no significant change in Ca(2+) content, compared with the H0 control (MT, 102.6+/-48.1). H3 larvae with the same treatment revealed about a 10-fold increase in accumulated Cd(2+), a 10% decrease in Ca(2+) content, but no change in MT (261.2+/-120.0), compared with the H3 control (MT, 330+/-74.0). H0 larvae could synthesize more MT to bind Cd(2+) for detoxification in 35 microg L(-1) Cd(2+), a dose that would not affect normal physiology or survival of H0 larvae. On the other hand, 35 microg L(-1) Cd(2+) caused H3 larvae to experience hypocalcemia, an abnormal physiological condition, in which H3 larvae could not synthesize sufficient MT, thus causing greater than 25% mortality. These results indicate for the first time that the inducibility of MT by waterborne Cd(2+) is development dependent, being correlated with inconsistent sensitivities to Cd(2+) during larval development.

A topological study of the human gamma-glutamyl carboxylase

gamma-Glutamyl carboxylase (GC), a polytopic membrane protein found in the endoplasmic reticulum (ER), catalyzes vitamin K-dependent posttranslational modification of glutamate to gamma-carboxyl glutamate. In an attempt to delineate the structure of this important enzyme, in vitro translation and in vivo mapping were used to study its membrane topology. Using terminus-tagged full-length carboxylase, expressed in 293 cells, it was demonstrated that the amino-terminus of the GC is on the cytoplasmic side of the ER, while the carboxyl-terminus is on the lumenal side. In addition, a series of fusions were made to encode each predicted transmembrane domain (TMD) followed by a leader peptidase (Lep) reporter tag, as analyzed by the computer algorithm TOPPRED II. Following in vitro translation of each fusion in the presence of canine microsomes, the topological orientation of the Lep tag was determined by proteinase K digestion and endoglycosidase H (Endo H) cleavage. From the topological orientation of the Lep tag in each fusion, the GC spans the ER membrane at least 5 times, with its N-terminus in the cytoplasm and its C-terminus in the lumen.

Polymorphisms in the coding exons of the human luteinizing hormone receptor gene. Mutations in brief no. 124. Online

Four polymorphisms were identified in the coding exons of the human luteinizing hormone/chorionic gonadotropin receptor (hLHR) gene. A CTGCAG insertion occurred after nucleotide 54 in 8 of 34 independent chromosomes examined. The heterozygosity frequency was 0.353. This Leu-Gln dipeptide insertion in the first Leucine repeat of the hLHR extracellular domain did not affect the ligand binding affinity of the receptor. Among the 54 chromosomes analyzed, 64.8% was A and 35.2% was G at nucleotide 872 in exon 10. The heterozygosity frequency was 0.115. The A/G substitution led to the replacement of Asn by Ser in the G allele and the abolition of a potential N-glycosylation site. Another polymorphism occurred at nucleotide 935. Fifty nine percent of chromosomes examined were A and 41% were G at this site with the encoded amino acid being Ser in the former and Asn in the latter. The heterozygosity frequency was 0.192. This polymorphism did not have biological consequence. Both of the exon 10 polymorphisms showed ethnic prevalence with the 872 G allele and 935 A allele predominantly in non-Caucasians. The fourth polymorphism was neutral and occurred at nucleotide 1065 in exon 11, with C in 60% and T in 40% of the 50 chromosomes examined. These polymorphisms are useful for tracking the inheritance of specific hLHR allele.