Mutation analysis of the coding sequences of MEK-1 and MEK-2 genes in human lung cancer cell lines

Recently, constitutively active mutants of MEK (MAP/ERK kinase) were shown to be capable of transforming cells to tumorigenicity suggesting that MEK can function as a dominant oncogene and potentially play a role in human carcinogenesis. Human lung cancer cells exhibit mutations in other components of the MAP kinase signaling pathway such as the Her-2/neu and ras oncogenes. Thus, the coding sequences of both MEK-1 and MEK-2 cDNAs from human lung cancer cell lines were screened by single strand conformation polymorphism analysis and DNA sequencing for alterations in these two genes. In 37 lung cancer cell lines we found: an allelic variant in MEK-1 cDNA, nt 783 G-->A, (no amino acid change); a MEK-2 cDNA change (nt 977 C-->T mutation leading to 298 Pro-->Leu change); a MEK-2 cDNA change nt 537 C-->T (no amino acid change); and a frequent MEK-2 cDNA germline polymorphism nt 744, A-->C (no amino acid change) with an allele frequency of 0.5 for each form. These results suggest that mutations in the MEK-1 and MEK-2 gene occur at a very low frequency in human lung cancer.

Hemagglutinin specificity and neuraminidase coding capacity of neuraminidase-deficient influenza viruses

Neuraminidase (NA)-deficient mutant virus stocks have been obtained by passaging A/NWS/33HA-tern/Australia/G70c/75NA (H1N9) influenza virus in medium containing neuraminidase from Micromonospora viridifaciens and antiserum against the influenza NA. Growth of the resulting mutants is dependent on addition of bacterial neuraminidase to the medium. Nucleotide sequence analysis showed large single deletions in the NA genes, with both ends of the NA gene segments conserved. These RNA fragments all have the capacity to code for a peptide that contains the N-terminal "tail" and membrane-anchoring region of the NA, but the presence of this peptide has not been demonstrated in virions or infected cells. In contrast to the ease of selection of NA-deficient mutants from the H1N9 virus, no mutants were selected from three other viruses. The HA-coding segments of parental H1N9 and mutant NWSc-Mvi predict a change of Pro to His at residue 227 (H3 numbering), close to the receptor-binding site of H3 HA, compared to the HA of an H1N2 reassortant that contains the NWS/33 HA gene. This change may contribute to an altered HA specificity that allows selection of mutants that can infect cells in the presence of high levels of NA activity. It appears that the role of NA in influenza infection is to remove sialic acid from the HA rather than to destroy receptors on cells.

Naturally processed T cell epitopes from human glutamic acid decarboxylase identified using mice transgenic for the type 1 diabetes-associated human MHC class II allele, DRB1*0401

The identification of class II binding peptide epitopes from autoimmune disease-related antigens is an essential step in the development of antigen-specific immune modulation therapy. In the case of type 1 diabetes, T cell and B cell reactivity to the autoantigen glutamic acid decarboxylase 65 (GAD65) is associated with disease development in humans and in nonobese diabetic (NOD) mice. In this study, we identify two DRB1*0401-restricted T cell epitopes from human GAD65, 274-286, and 115-127. Both peptides are immunogenic in transgenic mice expressing functional DRB1*0401 MHC class II molecules but not in nontransgenic littermates. Processing of GAD65 by antigen presenting cells (APC) resulted in the formation of DRB1*0401 complexes loaded with either the 274-286 or 115-127 epitopes, suggesting that these naturally derived epitopes may be displayed on APC recruited into pancreatic islets. The presentation of these two T cell epitopes in the islets of DRB1*0401 individuals who are at risk for type 1 diabetes may allow for antigen-specific recruitment of regulatory cells to the islets following peptide immunization.

Serum endometrial IgG antibodies and soluble CD23 concentrations in patients with endometriosis

OBJECTIVE

Serum endometrial antibodies have been found inconsistently in patients with endometriosis. Soluble CD23 is elevated in diseases associated with B cell activation. We evaluated serum levels of soluble CD23 and endometrial IgG antibodies in patients with endometriosis to determine whether there is B cell activation in this condition.

DESIGN

Fifty-seven patients with pelvic pain diagnosed as endometriosis and 40 patients without pelvic pain or endometriosis who had laparoscopic sterilisation were sequentially recruited into the study. Blood was collected and the sera assayed by ELISA for endometrial IgG antibodies and soluble CD23.

RESULTS

There was a significant difference between endometriosis and control group in both the serum IgG endometrial antibodies (p < 0.05) and soluble CD23 (p < 0.05). There was significant but weak correlation between endometrial antibodies and soluble CD23 (r = 0.3, p = 0.039), particularly in mild but not severe endometriosis.

CONCLUSIONS

These data suggest the existence of B cell activation in patients with endometriosis with a significant correlation between endometrial antibodies and soluble CD23. Mild endometriosis appears to be immunologically more active than the severe form. The value of soluble CD23 in the management of endometriosis needs further evaluation.

Soluble CD23 protein in the peritoneal fluid of patients with endometriosis

Activated B cells are known to produce soluble CD23 protein (sCD23) from their membranes. We recently showed a higher concentration of sCD23 in the serum of patients with endometriosis. As the commonest site of endometriosis is the peritoneal cavity, we sought to evaluate the concentration of sCD23 in the peritoneal fluid of 47 fertile symptomatic women with endometriosis and 35 fertile women without endometriosis. Endometriosis was diagnosed by laparoscopy and confirmed by histopathology. There was a statistically significant difference between the sCD23 concentrations in the endometriosis and control groups (P < 0.05). When endometriosis was defined based on the revised American Fertility Society (AFS) Score, patients with mild (AFS 1 and II) but not severe (AFS III and IV) endometriosis showed a higher and significant difference in the concentration of sCD23 when compared with the controls (P < 0.05). There was no significant correlation between the peritoneal fluid concentration of sCD23 and the phase of the menstrual cycle. We conclude that the concentration of sCD23 is higher in the peritoneal fluid of patients with endometriosis when compared with the controls, suggestive of B cell activation in patients with endometriosis. Furthermore, mild endometriosis is immunologically more active than severe endometriosis as defined by the current classification.

Xenopus Mad proteins transduce distinct subsets of signals for the TGF beta superfamily

Xenopus cDNAs homologous to the Drosophila Mad gene and C. elegans CEM genes have been cloned and functionally analyzed by microinjection into frog embryos. The results show that these genes (Xmad) encode intracellular proteins that act downstream of TGF beta superfamily ligands. Most interesting is the fact that different Xmad proteins produce distinct biological responses. Xmad1 produces ventral mesoderm, apparently transducing a signal for BMP2 and BMP4, whereas Xmad2 induces dorsal mesoderm like Vg1, activin, and nodal. These results suggest that an individual Xmad protein waits poised in the cytoplasm for instruction from a distinct subset of TGF beta ligands and then conveys specific information to the nucleus.

Molecular basis for the resistance of influenza viruses to 4-guanidino-Neu5Ac2en

We report the selection and characterization of influenza A/NWS-G70c and B/HK/8/73 (HG) viruses which are resistant to the potent influenza neuraminidase inhibitor, 4-guanidino-Neu5Ac2en. Viruses were selected which replicated in MDCK cells in the presence of 20 micrograms/ml inhibitor. The neuraminidase of resistant viruses was > 200-fold more resistant to 4-guanidino-Neu5Ac2en than was the neuraminidase of the parent viruses. Although amounts of neuraminidase protein were similar in resistant and parent viruses, the enzyme activity of the resistant neuraminidase heads was reduced by > 95% for the substrates used. Relative to parent viruses, the resistant viruses replicated to equal or greater titers in tissue culture and in embryonated chicken eggs. Sequence analysis revealed a single nucleotide mutation in the neuraminidase gene of each virus resulting in the change of the conserved Glu 119 (which lies in a pocket beneath the active site of the enzyme) to Gly thus eliminating an electrostatic interaction with the C-4 guanidinium moiety of the inhibitor. Mutations (Asn-->Ser) at amino acids 145 and 150 were also found in the hemagglutinin gene of the B/HK/8/73 (HG) virus resistant to 4-guanidino-Neu5Ac2en. No changes were found in the hemagglutinin gene of the resistant A/NWS-G70c virus.

Capsulotomy for phacoemulsification in hypermature cataracts

We describe a modified surgical technique of anterior capsulotomy and phacoemulsification for use in hypermature cataracts. Surgical steps included inferior linear capsulotomy with aspiration of milky cortex, inflation of the capsular sac with viscoelastic, a reverse triangular anterior capsulotomy with Vannas scissors, and in-the-bag bimanual sculpting of the nucleus. An oval 5 mm x 6 mm posterior chamber intraocular lens was used with single horizontal or no-stitch wound closure. The technique was used successfully in 20 cases of hypermature cataract. The mean time required to perform phacoemulsification was 3.46 minutes (range 1.2 to 6.3 minutes), with a standard deviation of 1.29. Visual acuity on the first postoperative day ranged from 20/20 to 20/60 (median 20/40). At one week, the mean astigmatism was 1.01 diopters (range 0.25 to 2.75 diopters). The mean endothelial cell loss was 13% (range 3.6% to 26.0%). Based on our results, the modified phacoemulsification technique merits consideration for use in hypermature cataracts.

Serum-soluble CD23 in patients with endometriosis and the effect of treatment with danazol and leuprolide acetate depot injection

Activated B cells have recently been shown to produce soluble CD23 from their membranes. The serum-soluble CD23 concentration in 21 patients with pelvic pain diagnosed as having endometriosis and confirmed by histology, and in 18 patients without pelvic pain, who had a normal pelvis during laparoscopic sterilization, was studied by chemiluminescent enzyme-linked immunosorbent assay. The endometriosis patients were randomized to 3 months of either danazol or leuprolide acetate injection. Serum was taken before and after 3 months of therapy. The serum-soluble CD23 concentration was significantly elevated in patients with endometriosis when compared with the controls (P < 0.0001). There was no correlation between soluble CD23 concentrations and the severity of endometriosis (r = 0.48, P > 0.05). The serum concentration of soluble CD23 decreased significantly on treatment with danazol but not leuprolide acetate (P < 0.05). We conclude that the elevation of soluble CD23 in patients with endometriosis suggests that there is activation of B cells, which respond to danazol but not leuprolide acetate injection.

An investigation to determine whether clusters of cancer types exist in nine breast-ovary families

Monte-Carlo simulations were carried out on nine BRCA1-linked families selected from the 1993 Breast Cancer Linkage Consortium. These families all displayed a prevalence of both breast and ovarian cancers, but little evidence was found to conclude that sufferers of either type formed clusters in particular branches of families. It was noted that the application of these methods to larger pedigrees with known probands would be useful in further clarifying the issue.

Scaled Model Studies of Heavy Oil Recovery From an Alaskan Reservoir Using Gravity-assisted Gas Injection

Abstract

Gas injection is one of the oldest enhanced oil recovery techniques used for recovering light oils. Recently, there has been renewed interest of gas injection in both light and heavy oil reservoirs. This recovery technique is particularly of interest for the heavy oil reservoirs of Alaska where the application of thermal techniques is limited due to reservoir depth and the existence of permafrost. It has been pointed out that, in order to apply gas injection, gravity stabilization is required. In absence of a natural dip, such gravity stabilization may be achieved through horizontal wells placed on top of the reservoir while producing through another horizontal well placed at the bottom of the reservoir. The possibility of such recovery technique has been investigated in this study.

A series of scaled model studies has been conducted using nitrogen, propane and carbon dioxide as injection fluids. The West Sak reservoir of North Slope, Alaska is used as the prototype for the present modeling study. Results indicate that close to 65% of the oil in place may be recovered by using gas injection from the top of a heavy oil reservoir. Even though similar ultimate recovery is obtained with gravity drainage alone, the time required to reach such a recovery is extremely long. However, these experimental runs are sensitive to the rate of gas injection. Experimental results suggest that there is an optimal gas injection pressure for nitrogen. Recovery mechanism is found to be different with propane than with nitrogen. However, the oil recovery remains higher with propane for all the cases studied. The highest recovery is obtained with carbon dioxide.

In all experiments, profuse viscous fingering takes place with different degrees of severity. This is found to be in agreement with a previously published stability theory. Viscous instability is considered to be harmless as final recovery is very high for all the cases. Final recovery with gas injection is significantly higher than the one with a waterflood.

Introduction

The oil production from Prudhoe Bay started to decline in 1989 and this necessitated the development of other petroleum resources. One such oil reserve is the West Sak reservoir located in the North Slope of Alaska. It is estimated to contain up to 3.2 × 109 m3 (25 billion barrels) of heavy oil in place. The high degree of variation in the oil gravity (12 to 22 ° API) and oil viscosity (30 to 3000 mPa •s) in highly heterogeneous, unconsolidated, fine grained sands, the presence of clay minerals, low permeability, highly faulted structure and a proximity to the overlying permafrost make the West Sak Reservoir very unique. The possibility of sharing the existing Kuparuk River Unit facilities makes the development and production of West Sak reservoir a near-term possibility.

ARCO Alaska Inc. conducted a waterflood pilot in 1984–1986 and it was found that West Sak reservoir lacks any natural drive mechanism. Also the high viscosities of West Sak crude make the reservoir a target for enhanced oil recovery (EOR) processes.

Amino-aromatic interaction between histidine 197 of the neurokinin-1 receptor and CP 96345

Substance P is a peptide neurotransmitter that binds to the neurokinin-1 receptor and is involved in pain transmission and neurogenic inflammation. Recently, a non-peptide substance P antagonist (CP 96345) has been shown to be effective in animal models of pain and inflammation. An understanding of the molecular interactions responsible for ligand binding will be critical for the development of more specific and selective antagonists for the neurokinin-1 receptor and for the discovery of new antagonists for related G-protein-coupled receptors. Here we report that histidine at position 197 in the fifth transmembrane helix of the human neurokinin-1 receptor binds specifically to CP 96345 but not to peptide agonists. Substitution of His 197 by different amino acids and analysis of structural analogues of antagonists suggest that His 197 is involved in an amino-aromatic interaction with the benzhydryl moiety of CP 96345.

Circadian periodicity of urinary inhibitor of calcium oxalate crystallization in healthy Indians and renal stone formers

The inhibitory activity (IA) of calcium oxalate crystallization was investigated in healthy Indians and renal stone formers. A marked circadian rhythm was observed in men and women of both groups. The rhythm pattern was similar on the basis of sex; however, it was different in stone formers as compared to normals. The acrophase for crystallization of calcium oxalate was observed, respectively, at 05.43 and 05.52 h in healthy men and women, and at 09.52 and 09.23 h in male and female renal stone formers. Moreover, the acrophase of percent inhibition by IA was observed at 17.44 and 17.52 h in healthy participants and at 21.52 and 21.27 h in male and female stone formers, respectively. Therefore, the acrophase suggests a highest risk of crystallization during the morning hours and a minimum one during the evening hours. The day-night rhythmic pattern of urinary calcium, magnesium and phosphorus is discussed in relation to the rhythm of IA.

Soluble CD23 levels are elevated in the serum of patients with primary Sjögren's syndrome and systemic lupus erythematosus

The low affinity IgE receptor Fc epsilon RII (CD23) is important in several aspects of T and B cell function. In this study serum levels of soluble CD23 (sCD23) were measured in three groups: 26 female patients with systemic lupus erythematosus (SLE), 21 females with primary Sjögren's syndrome (pSS) and 25 normal healthy females. The concentration of sCD23 was determined using an enhanced chemiluminescent sandwich ELISA developed in this laboratory. Increased levels of sCD23 were observed in pSS and in SLE patients compared with controls (median 23.0 versus 8.6, P less than 0.0002 and 18.1 versus 8.6, P less than 0.002 respectively). While the median level of sCD23 was found to be higher in pSS than in SLE the difference was not statistically significant. Patients with SLE and pSS on glucocorticoid treatment had significantly lower levels of sCD23 than patients not on this treatment (median 28.9 versus 14.4, P less than 0.05). Amongst the control patients sCD23 was inexplicably lower in the female members relative to the males (median 8.5 versus 12.3, P less than 0.05). Although serum IgG and IgA levels were significantly elevated in pSS and SLE patients relative to controls there was no direct correlation between sCD23 and the serum levels of these immunoglobulins. We conclude that B cell hyperactivity which occurs in both pSS and SLE is associated with raised levels of sCD23.

Characterization of the binding of a potent, selective, radioiodinated antagonist to the human neurokinin-1 receptor

We have synthesized a potent, selective, radioiodinated antagonist of the human neurokinin-1 (NK1) receptor and have characterized its binding to the cloned receptor expressed in Chinese hamster ovary cells. (cis)-2-(Diphenylmethyl)-N-[(2-iodophenyl)-methyl]-1- azabicyclo[2.2.2]octan-3-amine (L-703606) inhibits binding of 125I-Tyr8-substance P to the human NK1 receptor with an IC50 of 2 nM. This compound is a competitive antagonist of substance P-induced inositol phosphate generation, with a Kb of 29 nM. [125I]L-703606 binds to a single class of high affinity binding sites in human NK1/Chinese hamster ovary cell membranes (Kd = 0.3 nM). Substance P inhibits the binding of [125I]L-703606 to 65% of the NK1 receptor sites with a Kd of 0.04 +/- 0.03 nM and to the remaining 35% of the sites with a Kd of 1.5 +/- 0.7 nM. Addition of the nonhydrolyzable GTP analog guanylyl-5'-(beta, gamma-imido)diphosphate [Gpp(NH)p] shifts greater than 90% of the binding sites to the lower affinity state. In addition, Gpp(NH)p markedly alters the dissociation of substance P from the NK1 receptor by increasing the number of sites in the low affinity, rapidly dissociating state. However, Gpp(NH)p does not affect the rate of dissociation of [125I]L-703606. These data suggest that the pharmacological properties of [125I]L-703606 binding to the human NK1 receptor are similar to those of antagonists of nonpeptide guanine nucleotide-binding protein-coupled receptors and that this ligand will be useful for the biochemical and pharmacological characterization of the human NK1 receptor.

Portal-vein obstruction in children leads to growth retardation

The portal vein is the main source of blood and hepatotrophic factors to the liver. Partial portal-vein ligation in rats results in reduced growth compared with that in control rats. To investigate whether extrahepatic portal vein obstruction occurring in early childhood influences growth in humans, anthropometric and nutritional assessments were prospectively carried out in 61 patients with extrahepatic portal vein obstruction. Comparisons were made with 183 matched healthy controls using National Center of Health Statistics reference. Fifty-one percent of children with extrahepatic portal vein obstruction had stunted growth (height for age less than 90% of normal), compared with 16% of controls (p less than 0.01). Growth retardation was severe in patients with longer (greater than 5 yr) than with shorter (less than 2.5 yr) duration of clinical portal hypertension (height for age, 88.0 +/- 3.2 vs. 95.1 +/- 3.0; p less than 0.01). Little difference was seen in the energy intake (1,302 +/- 463 kcal/day vs. 1,335 +/- 449 kcal/day; p = not significant) and weight for height index (83.6 +/- 9.3 vs. 88.0 +/- 7.9; p = not significant) between extrahepatic portal vein obstruction patients and controls. This suggested that despite comparable nutrition, marked growth retardation occurred in extrahepatic portal vein obstruction patients. Incremental growth velocity was studied in 31 patients; in 24 (73%) the baseline Z score (-2.1 +/- 0.2) had decreased further (-2.4 +/- 0.2) at the end of follow-up (15.5 +/- 1.6 mo). Although the incremental height velocity was only 56% of the expected height, incremental weight gain was 98% of the expected weight for the attained height.(ABSTRACT TRUNCATED AT 250 WORDS)

The NPXY internalization signal of the LDL receptor adopts a reverse-turn conformation

Peptides corresponding to the proposed coated pit internalization signal of the native low density lipoprotein receptor, NPVY, take up in aqueous solution a reverse-turn conformation with the Asn in position i and the Tyr in position i + 3. By contrast, peptides derived from receptors that are defective for endocytosis do not adopt the reverse turn. These internalization-defective receptors include those with a nonaromatic residue substituted for the Tyr and those with Asn----Ala or Pro----Ala substitutions. While the tendency of an Asn-Pro sequence to induce a reverse turn was anticipated, the structural importance of an aromatic residue in position i + 3 was not. The sequences associated with the internalization signal thus appear to play a critical conformational role that is required for endocytosis, probably by enabling binding to adaptor molecules. With the results presented in the accompanying paper on lysosomal acid phosphatase, we now have direct evidence for previous proposals of a general correlation of internalization signals with a turn conformational motif.

Serum adenosine deaminase in pulmonary tuberculosis, malignancy and non-tubercular respiratory diseases

The study has been conducted to find out the serum ADA levels in 120 patients with various pulmonary diseases which included patients with tubercular pleural effusion (n = 86), lung cancer (n = 10) and patients with non-tubercular pulmonary diseases like pneumonia, etc (n = 24). Twenty healthy individuals served as control subjects. The mean (+/- SD) of ADA activity was 23.38 (4.47), 7.29 (1.08), 12.71 (1.95) and 2.23 (1.00) units/litre in tuberculosis, malignancy, non-tubercular pulmonary diseases and healthy controls respectively with significant difference between each other (P less than 0.001). Patients with tuberculosis (100%) fall in 97% sensitivity range with a lower cut off limit at 17 units/litre ADA activity, while for malignancy and non-tubercular respiratory diseases, the sensitivity was 90% and 83% respectively. Within the sensitivity limits, the serum ADA activity can be used for the differential diagnosis of pulmonary diseases.