Selective adsorption/recovery of Pb, Cu, and Cd with multiple fixed beds containing immobilized bacterial biomass

Fixed-bed columns packed with calcium alginate (CA)-immobilized biomass of Pseudomonas aeruginosa PU21 were utilized to remove lead (Pb), copper (Cu), and cadmium (Cd) from the contaminated water. In the absence of competing metals, saturation capacity of CA-immobilized cells in batch operations was 1.60, 2.42, and 1.06 mmol/g, for Pb, Cu, and Cd, respectively. The Langmuir constants (K) obtained from the Langmuir isotherm were 157.6, 4.2, and 3.7 mM-1 for Pb, Cu, and Cd, respectively. Results from single-metal biosorption with 10-cm immobilized-cell columns show that, for an influent metal concentration of 193 microM, the total capacities for Pb, Cu, and Cd, respectively, were 5.12, 4.03, and 3.48 mmol, which is nearly 25-30% higher than those obtained from columns containing only cell-free CA matrix. With the influent containing ternary mixtures of Pb, Cu, and Cd, columns with immobilized cells exhibited predominant selectivity to Pb, whereas in the cell-free columns, the dominance of Pb adsorption reduced, along with an appreciable increase in the adsorption of Cu. The metal-laden columns were regenerated by elution with HCl solution (pH 2.0). The metal recovery ratios were 80:1, 60:1, and 27:1 for Cu, Cd, and Pb, respectively. Moreover, with a pH gradient elution, the column-trapped metals can be optimally recovered at distinct pH values. Continuous biosorption of Pb, Cu, and Cu with four columns in series was also conducted. Results from the multibed operation demonstrate that Pb ions strongly inhibited the adsorption of Cu and Cd, which only occurred initially, and subsequently, an essential portion of the adsorbed Cu and Cd ions was replaced by Pb ions due to the ion exchange effect. However, since Pb ions were rapidly removed from the bulk at the onset of metal loading, Pb adsorption in columns 2-4 was negligible for the first 10-30 h, leading to an elevation in the breakthrough time (tb) and the capacity for Cu and Cd in columns 2-4. A back-propagation neural network model was shown to be able to predict the breakthrough curves of the three metals in the multicolumn processes with a ternary-metal feed.

Structure-activity relationships for a series of bis(phenylalkyl)amines: potent subtype-selective inhibitors of N-methyl-D-aspartate receptors

A series of bis(phenylalkyl)amines, structural analogues of ifenprodil and nylidrin, were synthesized and tested for antagonism of N-methyl-D-aspartate (NMDA) receptors. Potency and subunit selectivity were assayed by electrical recordings in Xenopus oocytes expressing three binary combinations of cloned rat NMDA receptor subunits: NR1A expressed in combination with either NR2A, NR2B, or NR2C. The bis(phenylalkyl)amines were selective antagonists of NR1A/2B receptors. Assayed under steady-state conditions, the most potent of these, N-[2-(4-hydroxyphenyl)ethyl]-5-phenylpentylamine hydrochloride (20), has an IC50 value of 8 nM and >1000-fold selectivity with respect to NR1A/2A and NR1A/2C receptors. The structure-activity relationship of the bis(phenylalkyl)amine series indicates that the piperidine ring and alkyl chain substitutions common to NR2B-selective antagonists such as ifenprodil, CP 101,606, and Ro 25-6981 are not necessary to generate potent and selective ligands. The primary determinants of potency are the phenolic OH group, acting as a hydrogen bond donor, the distance between the two rings, and an electrostatic interaction between the receptor and the basic nitrogen atom. This study provides a framework for designing structurally novel NR2B-selective antagonists which may be useful for treatment of a variety of neurological disorders.

Preparation and transplantation of photoreceptor sheets

PURPOSE

Photoreceptor (PR) transplantation may be a treatment for blindness secondary to PR degeneration. We studied different technical aspects of PR-sheet preparation.

METHODS

Geographic variation in the thickness of the cat PR layer (from the outer segments to the outer plexiform layer) and inner retina (width of the remainder of the retina) was studied. PR sheets (cat and human) were prepared through gelatin embedding and subsequent vibratoming or excimer laser ablation. Cat PR sheets were evaluated after transplantation.

RESULTS

The thickness of the cat PR layer and inner retina varied in different regions. The superior central retina, including the area centralis, was thickest (PR layer: 115-123 microm, entire retina: 225-230 microm, in fixed tissue). The peripheral retina was approximately 40% thinner than the center. Fresh retina was approximately 7.9% thicker than the fixed retina. Both vibratomy and excimer laser ablation removed the inner retina, leaving a PR-layer sheet with good morphology. To produce good quality PR sheets with vibratomy, use of different gelatin concentrations (2% to 35%) at various stages of sheet preparation was crucial. To produce PR sheets of uniform thickness with excimer laser ablation, control of fluid on the retinal surface was critical. Twenty-four hours after PR transplantation surgery, donor PR cells were well oriented and in close contact with host retinal pigment epithelial cells. Gelatin supporting the transplant dissolved as early as 100 min after surgery.

CONCLUSIONS

We confirmed and expanded the work of previous investigators and showed that cat and human PR sheets can be manufactured using vibratomy or excimer laser ablation. This preparation provides a well oriented and organized PR cell layer after transplantation.

The expression of vascular endothelial growth factor isoforms in cultured human endometrial stromal cells and its regulation by 17beta-oestradiol

Angiogenesis or formation of new blood vessels is required for regeneration of the endometrium after its breakdown during each menstruation. Vascular endothelial growth factor (VEGF), a family of recently discovered angiogenic factors, may be involved in the repair and growth of the endometrium. In this study reverse transcription-polymerase chain reaction (PCR) was used to confirm the presence of VEGF mRNA and restriction enzyme digestion to confirm the identity of PCR products generated from different VEGF isoforms in cultured human endometrial stromal cells. The shortest isoform, VEGF 121, was the most abundant in quiescent stromal cells. It was about one-and-a-half times that of VEGF 165. The longest isoform, VEGF 206, was not detected; only a relatively weak signal for VEGF 189 was detectable. The mRNA for VEGF increased 2-fold after stimulation by 17beta-oestradiol (10 nM) for 30 min. A further increase to 3-fold above baseline occurred after 2 h incubation and remained steady at 6 h incubation, but decreased to 2-fold of baseline after 15 h. There was no differential stimulation of mRNA for VEGF isoforms: the ratio of VEGF 121 to 165 remained constant at 3:2 during the course of the incubation, with the exception at 15 h incubation when the ratio was 2:1. The VEGF protein, determined by specific enzyme immunoassay, increased from undetectable at baseline to 79.8 +/- 18.9 pg/ml (n = 4, mean +/- SD, 9.6 cm2/well/ml) after 2 h, with a further significant increase to 249.5 +/- 27.3 pg/ml after 15 h and 695.0 +/- 41.4 pg/well after 39 h. At 15 h incubation, the specific oestradiol antagonist ICI 182,780 (1 microM) significantly reduced VEGF secretion by 25% from 249.5 +/- 27.3 to 189.0 +/- 26.6 pg/ml. Thus, VEGF showed specific patterns of isoform expression in the human endometrial stromal cells; oestradiol (10 microM) stimulated, but not differentially, the mRNA for VEGF isoforms.

Interleukin-1 beta induces cyclooxygenase-2 gene expression in cultured endometrial stromal cells

Increasing evidence indicates that PGs may play an obligatory role in blastocyst implantation. Cyclooxygenase (also known as PGH synthase) isozymes 1 and 2 catalyze the rate limiting steps in the biosynthesis of PGs. The ubiquitous cyclooxygenase-1 (COX-1) subserves housekeeping functions, whereas the inducible cyclooxygenase-2 (COX-2) is expressed by limited cell types and tightly controlled. Here we report the induction of COX-2 gene expression by interleukin-1 beta (IL-1 beta) in cultured human endometrial stromal cells. COX-2 activity was induced by IL-1 beta (1 ng/mL); conversion of exogenous arachidonic acid to PGF2 alpha increased from 2.6 +/- 0.6 ng/well (mean +/- SEM; n = 6) to 22.2 +/- 5.6 ng, but was completely blocked (2.8 +/- 0.7 ng/well) by NS-398, a specific COX-2 inhibitor. Undetectable in quiescent stromal cells, messenger ribonucleic acid for COX-2 was induced 30 min after IL-1 beta treatment, reached a maximum at 4 h, and decreased after 15 h. Protein synthesis was not required for induction of the COX-2 gene, as it was blocked by actinomycin D but not by cycloheximide. The 70-kDa COX-2 protein was not detected in quiescent cells, became detectable 6 h after IL-1 beta treatment, and remained detectable even after 15 h. IL-1 beta (0.1-100 ng/mL) increased the luciferase activity in promoterless luciferase reporter containing the 900-bp 5'-flanking sequence (-891 to +9) of the COX-2 gene in a dose-dependent manner, with an ED50 of 0.1-1 ng/mL.

5-(N-oxyaza)-7-substituted-1,4-dihydroquinoxaline-2,3-diones: novel, systemically active and broad spectrum antagonists for NMDA/glycine, AMPA, and kainate receptors

A group of 5-aza-7-substituted-1,4-dihydroquinoxaline-2,3-diones (QXs) and the corresponding 5-(N-oxyaza)-7-substituted QXs were prepared and evaluated as antagonists of ionotropic glutamate receptors. The in vitro potency of these QXs was determined by inhibition of [3H]-5,7-dichlorokynurenic acid ([3H]DCKA) binding to N-methyl-D-aspartate (NMDA)/glycine receptors, [3H]-(S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ([3H]AMPA) binding to AMPA receptors, and [3H]kainate ([3H]KA) binding to KA receptors in rat brain membranes. 5-(N-Oxyaza)-QXs 12a-e all have low micromolar or submicromolar potency for NMDA/glycine receptors and low micromolar potencies for AMPA and KA receptors. QXs 12a-e display 2-12-fold selectivity for NMDA/glycine receptors compared to AMPA receptors, and approximately 2-fold difference between AMPA and KA potency. In contrast to other QXs that either show high selectivity for NMDA (such as ACEA 1021) or AMPA (such as NBQX) receptors, these molecules are broad spectrum antagonists of ionotropic glutamate receptors. 7-Nitro-5-(N-oxyaza)-QX (12e) is the most potent inhibitor among 12a-e, having IC50 values of 0.69, 1.3, and 2.4 microM at NMDA, AMPA, and KA receptors, respectively. In functional assays on glutamate receptors expressed in oocytes by rat cerebral cortex poly(A+) RNA, 7-chloro-5-(N-oxyaza)-QX (12a) and 7-nitro-5-(N-oxyaza)-QX (12e) have Kb values of 0.63 and 0.31 microM for NMDA/glycine receptors, and are 6- and 4-fold selective for NMDA over AMPA receptors, respectively. 5-(N-Oxyaza)-7-substituted-QXs 12a-e all have surprisingly high in vivo potency as anticonvulsants in a mouse maximal electroshock-induced seizure (MES) model. 7-Chloro-5-(N-oxyaza)-QX (12a), 7-bromo-5-(N-oxyaza)-QX (12b), and 7-methyl-5-(N-oxyaza)-QX (12c) have ED50 values of 0.82, 0.87, and 0.97 mg/kg i.v., respectively. The high in vivo potency of QXs 12a-e is particularly surprising given their low log P values (approximately -2.7). Separate studies indicate that QXs 12a and 12e are also active in vivo as neuroprotectants and also have antinociceptive activity in animal pain models. In terms of in vivo activity, these 5-(N-oxyaza)-7-substituted-QXs are among the most potent broad spectrum ionotropic glutamate antagonists reported.

Preservation of pudendal afferents in sacral rhizotomies

OBJECTIVE

To assess the effectiveness of pudendal afferent mapping as a tool to minimize the risk of postoperative bowel, bladder, and sexual dysfunction in patients undergoing selective posterior rhizotomies in whom the S2 roots are candidates for rhizotomy.

METHODS

One-hundred fourteen children with the diagnosis of cerebral palsy and debilitating spasticity were selected to undergo selective posterior rhizotomies at New York University Medical Center during 1991 through 1995. There were 72 male and 42 female patients with a mean age of 3.8 years. At the time of surgery, none of the patients had clinically relevant bladder dysfunction. Dorsal root action potentials were recorded intraoperatively to map the distribution of pudendal afferent fibers in S1-S3 roots bilaterally before performing the rhizotomies.

RESULTS

Pudendal afferent mapping was successful in 105 of 114 patients. In the majority of these patients (56%), the distribution was asymmetrical. S1 roots contributed 4%, S2 roots 60.5%, and S3 roots 35.5% of the overall pudendal afferent activity. The pudendal afferent distribution was often confined to a single level in 18% of the patients or even to a single root in 7.6%. Fifty-six percent of the pathologically responding S2 roots during rhizotomy testing were preserved because of the significant afferent activity, as demonstrated during pudendal mapping. None of the 105 patients so mapped developed long-term bowel or bladder complications.

CONCLUSIONS

Pudendal afferent mapping identifies S2 roots that carry a significant number of fibers involved with genital sensation. The preservation of such roots during surgical procedures may be important for sexual function and may also contribute to decreasing postoperative bladder and bowel disturbances.

Characterization of a lily tapetal transcript that shares sequence similarity with a class of intracellular pathogenesis-related (IPR) proteins

This study addresses isolating and characterizing a cDNA clone corresponding to a tapetum-specific transcript, designated as PR-10a from Lilium longiflorum. Anther ontogeny is histologically divided into three consecutive phases. The first encompasses early proliferative stages and differentiation of the locules. The second concerns microspore development from the onset of meiosis through microspore maturation. The final phase involves pollen maturation, originating with microspore mitosis through pollen formation. The lily PR-10a transcript is anther-specific and temporally expressed only at the phase of microspore development during which the tapetal cells become polarized, highly secretory, and exhibit loss of cell walls. The maximal level of PR-10a transcript coincides strictly with the peak of tapetal secretory function. Comparing mRNA and cDNA insert sizes reveals that PR-10a is close to full-length. Sequence analysis demonstrates similarity between the predicted lily PR-10a and asparagus AoPR1 protein, potato pSTH2 and pSTH21 proteins, parsley PcPR1 and PcPR3 proteins, bean PvPR1 and PvPR2 proteins, lupin L1R18B protein, pea 149 protein and a family of major allergens including Cor a 1 of hazel, Car b 1 of hornbeam, Aln g 1 of alder, Bet v 1 of birch and Api g 1 of celery. To the authors' knowledge, this is the first reported organ/tissue-specific IPR protein.

Differential expression of photoreceptor-specific proteins during disease and degeneration in the progressive rod-cone degeneration (prcd) retina

Progressive rod-cone degeneration (prcd) is a late-onset hereditary retinal degeneration characterized by normal development of photoreceptors prior to degeneration and death of visual cells. We reported previously that expression of opsin mRNA and protein decreases prior to visual cell degeneration. To examine the specificity of this reduction, we have used immunocytochemistry to correlate photoreceptor-specific protein expression with visual cell disease progression. Eyes from light-adapted age-matched control and prcd-affected dogs were fixed in paraformaldehyde, embedded in diethylene glycol distearate (DGD) wax, and reacted with antibodies specific to interphotoreceptor retinoid-binding protein (IRBP), S-antigen, opsin, phosducin, gamma-phosphodiesterase (gamma-PDE), and beta 1-transducin. While IRBP expression did not change with disease progression, immunoreactivity to other proteins varied. For S-antigen and opsin, immunoreactivity decreased dramatically with the transition from photoreceptor disease to degeneration; gamma-PDE immunolabeling in rods also decreased, but the reduction was less abrupt. However, for two other proteins (phosducin and beta 1-transducin), immunoreactivity increased initially and was redistributed (particularly to the rod outer segment) in early disease (stage 1). Our results show that there is a differential expression of photoreceptor-specific proteins with disease and degeneration that is not uniform for all the gene products examined; expression can be decreased, altered in distribution or remain unchanged. It is clear that the decrease of opsin expression described previously is not an isolated phenomenon in the progression of prcd, but is part of a more generalized degenerative process which eventually culminates in cell death.

Standardization and a multilaboratory comparison of Neisseria meningitidis serogroup A and C serum bactericidal assays. The Multilaboratory Study Group

A standardized serum bactericidal assay (SBA) is required to evaluate the functional activity of antibody produced in response to Neisseria meningitidis serogroup A and C vaccines. We evaluated assay parameters (assay buffer, target strains, growth of target cells, target cell number, complement source and concentration, and methods for growth of surviving bacteria) which may affect the reproducibility of SBA titers. The various assay parameters and specificity of anticapsular antibody to five serogroup A strains (A1, ATCC 13077, F8238, F9205, and F7485) and four serogroup C strains (C11, G7880, G8050, and 1002-90) were evaluated with Centers for Disease Control and Prevention meningococcal quality control sera. The critical assay parameters for the reproducible measurement of SBA titers were found to include the target strain, assay incubation time, and complement. The resulting standardized SBA was used by 10 laboratories to measure functional anticapsular antibody against serogroup A strains F8238 and serogroup C strain C11. In the multilaboratory study, SBA titers were measured in duplicate for 14 pairs of sera (seven adults and seven children) before and after immunization with a quadrivalent polysaccharide (A, C, Y, and W-135) vaccine. The standardized SBA was reliable in all laboratories regardless of experience in performing SBAs. For most sera, intralaboratory reproducibility was +/- 1 dilution; interlaboratory reproducibility was +/- 2 dilutions. The correlation between median titers (interlaboratory) and enzyme-linked immunosorbent assay total antibody concentrations was high for both serogroup A (r = 0.86; P < 0.001; slope = 0.5) and serogroup C (n = 0.86; P < 0.001; slope = 0.7). The specified assay, which includes the critical parameters of target strain, incubation time, and complement source, will facilitate interlaboratory comparisons of the functional antibody produced in response to current or developing serogroup A and C meningococcal vaccines.

Structure-activity relationships of 4-hydroxy-3-nitroquinolin-2(1H)-ones as novel antagonists at the glycine site of N-methyl-D-aspartate receptors

A series of 4-hydroxy-3-nitroquinolin-2(1H)-ones (HNQs) was synthesized by nitration of the corresponding 2,4-quinolinediols. The HNQs were evaluated as antagonists at the glycine site of NMDA receptors by inhibition of [3H]DCKA binding to rat brain membranes. Selected HNQs were also tested for functional antagonism by electrophysiological assays in Xenopus oocytes expressing either 1a/2C subunits of NMDA receptors or rat brain AMPA receptors. The structure-activity relationships (SAR) of HNQs showed that substitutions in the 5-, 6-, and 7-positions in general increase potency while substitutions in the 8-position cause a sharp reduction in potency. Among the HNQs tested, 5,6,7-trichloro HNQ (8i) was the most potent antagonist with an IC50 of 220 nM in [3H]DCKA binding assay and a Kb of 79 nM from electrophysiological assays. Measured under steady-state conditions HNQ 8i is 240-fold selective for NMDA over AMPA receptors. The SAR of HNQs was compared with those of 1,4-dihydroquinoxaline-2,3-diones (QXs) and 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes (QTOs). In general, HNQs have similar potencies to QXs with the same benzene ring substitution pattern but are about 10 times less active than the corresponding QTOs. HNQs are more selective for NMDA receptors than the corresponding QXs and QTOs. The similarity of the SAR of HNQs, QXs, and QTOs suggested that these three classes of antagonists might bind to the glycine site in a similar manner. With appropriate substitutions, HNQs represent a new class of potent and highly selective NMDA receptor glycine site antagonists.

Another look at chronic appendicitis resembling Crohn's disease

There is an uncommon, enigmatic chronic appendicitis that shares histologic features with typical Crohn's disease (CD), but it presents as appendiceal disease. Although most reported patients remain disease free after appendectomy, a small group progresses to more generalized CD. The density of granulomas is said to separate those patients whose disease remains confined to the appendix from those patients in whom CD develops elsewhere. We reviewed 20 cases of appendicitis morphologically resembling CD and compared them with 16 transmurally inflamed appendices from patients with known CD to evaluate whether any histologic features differentiate between patients in whom recurrent CD will develop in the gut and those in whom it will not. Eleven patients with the primary disease had no granulomas. The remaining nine patients had granulomas, ranging from 0.2 to 28 per cross section. Appendices from patients known to have CD never had more than 10.5 granulomas per cross section. Follow-up in 15 patients with the primary appendiceal disease was from 5 weeks to 11.5 years (median, 30 mo). Thirteen patients remained disease free, but in two, CD developed elsewhere in the gut. One of these had no granulomas, whereas the other one had 21 per cross section. Therefore, according to the data from our study and from other studies, most cases of this Crohn's-like disease of the appendix are self-limited, but a few are not. Histologic features alone, including granuloma density, do not always predict the clinical outcome. Follow-up is necessary.

The effect of elevated serum progesterone during ovulation induction in in vitro fertilization-embryo transfer

OBJECTIVE

Our purpose was to determine whether elevated progesterone (P) during ovulation induction in IVF-ET cycles is a poor prognostic factor for achieving pregnancy.

DESIGN

We retrospectively reviewed 672 consecutive IVF-ET cycles in which ovulation was performed using luteal LA downregulation and hMG.

SETTING

The ART program at the Brigham & Women's Hospital, a tertiary care institution, was the study setting.

MAIN OUTCOME MEASURES

Patients were divided into groups by serum P levels at baseline, on stimulation day 5, on the day of hCG injection, and, on the day after hCG injection and the following parameters were compared: duration of luteal LA treatment, number of ampoules of hMG used, estradiol (E2) levels, number of follicles > or = 12 mm, number of follicles > or = 15 mm, number of oocytes, number of normal embryos, number of polyspermic embryos, fertilization rate, implantation rate, and clinical and ongoing/live birth pregnancy rates.

RESULTS

Based on serum P level, patients were divided into three groups: Group I, < or = 0.31 ng/ml (conversion factor to SIU, 3.180); Group II, and > 0.3 and < 1.0 ng/ml and Group III, > or = 1.0 ng/ml. Measureable P at baseline was associated with a higher cancellation rate, but no difference in other cycle outcome parameters. Progesterone > 0.31 ng/ml on stimulation day 5 was associated with a higher fertilization rate in Groups II and III, but there was no difference in the clinical pregnancy or ongoing/live birth rates among the three groups. Based on P on the day of hCG administration, Groups II and III had significantly more oocytes and higher fertilization rates than did Group I, however, clinical pregnancy and ongoing/live birth rates were not significantly different. On the day after hCG, there was a trend toward a higher clinical pregnancy rate in Group III, which had younger patients, better follicular recruitment, and more embryos than Groups I or II, but these differences did not reach statistical significance.

CONCLUSIONS

Serum P > 0.31 ng/ml during ovulation induction reflects good follicular recruitment, and is not a predictor of IVF outcome.

Selective absence of cone outer segment beta 3-transducin immunoreactivity in hereditary cone degeneration (cd)

We have used immunocytochemistry and in situ hybridization to examine the expression of photoreceptor specific genes in retinas of normal dogs and those affected with hereditary cone degeneration (cd), a rare autosomal recessive disorder that selectively affects cones. In the cd retina, cone disease begins early in life; cones are lost by extrusion of the nucleus into the inner segment, and later by displacement of the nucleus, surrounded by a thin rim of cytoplasm, into the interphotoreceptor space. Two micrometer sections from the superior and inferior retinal meridians, extending from the optic disk to the ora serrata, were used for in situ hybridization with a bovine rod opsin and human red/green cone opsin cRNA probes, or were reacted with antibodies directed against photoreceptor-specific proteins and visualized with appropriate biotinylated antibodies. Antibodies against the following proteins were used: alpha- and beta 3-transducins, phosducin, alpha/beta- and gamma-phosphodiesterases, COS-1, and OS-2, opsin, S-antigen and IRBP. Immunoreactivity or hybridization labeling was evaluated in unstained sections; cone pathology was judged in adjacent Toluidine Blue-stained sections. With these methods it was possible to evaluate immunoreactivity or hybridization labeling and cone pathology at the single cell level. Both middle-(COS-1) and short-(OS-2) wavelength-sensitive cones were present in controls and cd affected retinae at 2.2 months, and distinct transcripts of the red/green cone pigment gene were identified in the majority of cones in both normal and affected retinas at this age. However, beta 3-transducin immunoreactivity was completely absent from cd-affected cone outer segments. Both cone types were present but in reduced numbers in older animals (11.5 and 17 months), and no reactivity to beta 3-transducin was noted. No differences were found with the other antibodies used. The specific absence of beta 3-transducin immunoreactivity from the cone outer segments suggests a potential involvement of the beta 3-transducin gene or gene product in the disease process.

Synthesis and structure-activity relationships of 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes: novel and highly potent antagonists for NMDA receptor glycine site

A series of 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes (QTOs) was synthesized and evaluated for antagonism of NMDA receptor glycine site. Glycine site affinity was determined using a [3H]DCKA binding assay in rat brain membranes and electrophysiologically in Xenopus oocytes expressing 1a/2C subunits of cloned rat NMDA receptors. Selected compounds were also assayed for antagonism of AMPA receptors in Xenopus oocytes expressing rat brain poly-(A)+RNA. QTOs were prepared by nitrosation of 2,4-quinolinediols. Structure-activity studies indicated that substitutions in the 5-, 6-, and 7-positions increase potency, whereas substitution in the 8-position causes a decrease in potency. Among the derivatives evaluated, 5,6,7-trichloro-QTO was the most potent antagonist with an IC50 of 7 nM in the [3H]DCKA binding assay and a Kb of 1-2 nM for NMDA receptors expressed in Xenopus oocytes. 5,6,7-Trichloro-QTO also had a Kb of 180 nM for AMPA receptors in electrophysiological assays. The SAR of QTOs was compared with the SAR of 1,4-dihydroquinoxaline-2,3-diones (QXs). For compounds with the same benzene ring substitution pattern, QTOs were generally 5-10 times more potent than the corresponding QXs. QTOs represent a new class of inhibitors of the NMDA receptor which, when appropriately substituted, are among the most potent glycine site antagonists known.

Epidermal growth factor and basic fibroblast growth factor in peritoneal fluid of women with endometriosis

OBJECTIVE

To determine and compare the concentrations of epidermal growth factor (EGF) and basic fibroblast growth factor (FGF) in the peritoneal fluid of women with and without endometriosis.

DESIGN

Prospective study.

SETTING

Tertiary care center affiliated with university medical school.

PATIENTS

Forty-two women with endometriosis and 34 women without endometriosis confirmed by laparoscopy.

MAIN OUTCOME MEASURES

Epidermal growth factor and basic FGF concentrations were determined by highly sensitive enzyme immunoassays using monoclonal antibodies.

RESULT

Approximately 50% of the PF samples had EGF concentrations of > 0.4 pg/mL (conversion factor to SI unit, 0.17) and 90% had basic FGF concentrations of > 1 pg/mL (conversion factor to SI unit, 0.058). Concentrations of EGF or basic FGF in PF did not differ significantly between the two groups. In normal women, there was a significant correlation between EGF and basic FGF during the luteal phase. In women with endometriosis, EGF levels were higher during the luteal phase, but there was no correlation of either EGF or basic FGF levels with the severity of endometriosis.

CONCLUSIONS

The concentrations of EGF and basic FGF were highly variable in the PF of women with or without endometriosis and did not differ significantly. The concentrations were so low that neither EGF nor basic FGF in PF could bind to its receptor.

Synthesis and structure-activity relationships of substituted 1,4-dihydroquinoxaline-2,3-diones: antagonists of N-methyl-D-aspartate (NMDA) receptor glycine sites and non-NMDA glutamate receptors

A series of mono-, di-, tri-, and tetrasubstituted 1,4-dihydroquinoxaline-2,3-diones (QXs) were synthesized and evaluated as antagonists at N-methyl-D-aspartate (NMDA)/glycine sites and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-preferring non-NMDA receptors. Antagonist potencies were measured by electrical assays in Xenopus oocytes expressing rat whole brain poly(A)+ RNA. Trisubstituted QXs 17a (ACEA 1021), 17b (ACEA 1031), 24a, and 27, containing a nitro group in the 5 position and halogen in the 6 and 7 positions, displayed high potency (Kb approximately 6-8 nM) at the glycine site, moderate potency at non-NMDA receptors (Kb = 0.9-1.5 microM), and the highest (120-250-fold) selectivity in favor of glycine site antagonism over non-NMDA receptors. Tetrasubstituted QXs 17d,e were more than 100-fold weaker glycine site antagonists than the corresponding trisubstituted QXs with F being better tolerated than Cl as a substituent at the 8 position. Di- and monosubstituted QXs showed progressively weaker antagonism compared to trisubstituted analogues. For example, removal of the 5-nitro group of 17a results in a approximately 100-fold decrease in potency (10a,b,z), while removal of both halogens from 17a results in a approximately 3000-fold decrease in potency (10v). In terms of steady-state inhibition, most QX substitution patterns favor antagonism at NMDA/glycine sites over antagonism at non-NMDA receptors. Among the QXs tested, only 17i was slightly selective for non-NMDA receptors.

Characterization of protein production by caprine placental membranes: identification and immunolocalization of retinol-binding protein

Caprine chorion, allantois and amnion from days 23, 28, 35, 39 and 45, and yolk sac from day 23 of pregnancy were isolated by dissection and cultured for 24 h in modified minimum essential medium in the presence of [35S] methionine. De novo-synthesized proteins released into the culture medium were analyzed by two-dimensional PAGE and fluorography. Patterns of protein production by these isolated extraembryonic membranes remained relatively unchanged from days 23 to 45 of pregnancy. Electrophoretic profiles of proteins synthesized by allantois and amnion were identical but distinct from that produced by chorion. Yolk sac was the major source of serum-like proteins. An acidic (pI 5.3-6.3) 22 kDa protein, which consisted of four isoelectric variants, was produced by all extraembryonic membranes and demonstrated to immunoreact with antiserum produced against bovine placental retinol-binding protein (RBP). Limited N-terminal sequence analysis of one major isoform indicated that the protein had complete homology with bovine RBP over the first 15 amino acids. Immunoreactive RBP was localized in epithelial cells lining the chorion, allantois and amnion. In this study, we have characterized and compared protein production by isolated extraembryonic membranes through days 23 to 45 of pregnancy and identified the 22 kDa protein as caprine RBP of placental origin.

Baboon corpus luteum: epidermal growth factor receptor messenger ribonucleic acid expression during early, midluteal, and late luteal phases

OBJECTIVE

To determine the presence and compare the relative abundance of messenger RNA for epidermal growth factor receptor (EGFR) in baboon corpora lutea of different luteal ages.

DESIGN

Prospective controlled nonhuman primate study.

SETTING

Animal facility in an academic research institution.

PARTICIPANTS

Six adult female baboons with well-defined regular menstrual cycles. Stage of the menstrual cycle was determined by observation and scoring of perineal turgescence. The day of maximal turgescence was referred to as the day of LH surge.

INTERVENTION

Ten corpora lutea were obtained by luteectomy during early (LH + 1 to 5 days, n = 3), midluteal (LH + 6 to 10 days, n = 3), and late (LH + 11 to 15 days, n = 4) luteal phases.

MAIN OUTCOME MEASURE

Relative levels of messenger RNA for EGFR as determined by ribonuclease protection assay using RNA probe generated from complementary DNA for human EGFR.

RESULTS

Messenger RNA for EGFR is present in baboon corpora lutea with relative levels of 0.51 +/- 0.18 (mean +/- SEM) in the early, 0.43 +/- 0.17 in the midluteal, and 0.50 +/- 0.17 arbitrary units in the late luteal phase.

CONCLUSION

Baboon corpus luteum is a site of EGFR production; the levels of its messenger RNA did not change appreciably throughout the luteal phase.

Substrate spectrum of human excinuclease: repair of abasic sites, methylated bases, mismatches, and bulky adducts

Nucleotide-excision repair is the repair system for removing bulky lesions from DNA. Humans deficient in this repair pathway suffer from xeroderma pigmentosum (XP), a disease characterized by photodermatoses, including skin cancers. At the cellular level, XP patients fail to remove cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone photoproducts induced by UV light, as well as other bulky DNA lesions caused by various genotoxic agents. XP cells are not particularly sensitive to ionizing radiation or to alkylating agents that cause mostly nonbulky DNA lesions. Therefore, it has generally been assumed that the human nucleotide-excision repair enzyme (excinuclease) is specific for bulky adducts. To determine the substrate range of human excinuclease we used the highly sensitive excision assay and tested bulky adducts, synthetic apurinic/apyrimidinic sites, N6-methyladenine, O6-methylguanine, and mismatches as potential substrates. We found that all of these "lesions" were removed by human excinuclease, although with vastly different efficiencies.

Human and E.coli excinucleases are affected differently by the sequence context of acetylaminofluorene-guanine adduct

Synthetic DNA substrates containing an acetylaminofluorene (AAF) adduct at each of the three guanine in the G1G2CG3CC sequence were constructed and tested as substrates for reconstituted E.coli (A)BC excinuclease and human excinuclease in HeLa cell-free extract (CFE). The (A)BC excinulcease repaired the three substrates with relative efficiencies of G1:G2:G3 of 100:18:66 in agreement with an earlier report [Seeberg, E., and Fuchs, R.P.P. (1990) Proc. Natl Acad. Sci. USA 87, 191-194]. The same lesions were repaired by the human excinuclease with the strikingly different efficiencies of G1:G2:G3 as 38:100:68. These results reveal that the human excinuclease is affected by the sequence context of the lesion in a different manner than its prokaryotic counterpart.

HMG-domain proteins specifically inhibit the repair of the major DNA adduct of the anticancer drug cisplatin by human excision nuclease

The most frequent DNA adduct made by the anticancer drug cisplatin, the 1,2-intrastrand d(GpG) cross-link, as well as the minor 1,3-intrastrand d(GpTpG) adduct, were both repaired by an in vitro human excision repair system. Fragments of 27-29 nt containing the platinum damage were excised. The high mobility group (HMG)-domain proteins HMG1 and human mitochondrial transcription factor specifically inhibited repair of the 1,2-intrastrand cross-link by the human excision nuclease. These results suggest that the types and levels of HMG-domain proteins in a given tumor may influence the responsiveness of that cancer to cisplatin chemotherapy and they provide a rational basis for the synthesis of new platinum anticancer drug candidates.

Spontaneous rupture of the liver associated with pregnancy: a report of two cases

Spontaneous rupture of the liver associated with pregnancy is a rare and grave complication, usually occurring in preeclampsia or eclampsia. Two cases of ruptured subcapsular hematoma of the right liver during pregnancy are reported. The first case was a 19-year-old woman who had suffered from epigastralgia and absent fetal heart beat in the 32nd week of gestation. The second case was a 31-year-old female who complained of nausea and right upper quadrant pain in the 35th week of pregnancy. Both had preeclampsia, and developed shock with disseminated intravascular coagulation soon after admission. Both received surgery and were found to have ruptured hematoma over the right liver. Finally, the first patient died of renal failure, but the second survived because preoperative diagnosis had been exact. Greater suspicion, then awareness of diagnosis can lead to better timing of surgery and an improved prognosis for mother and child.