Lack of natural killer cell augmentation in vitro by human interferon gamma in a subset of patients with systemic sclerosis

Systemic sclerosis (SSc) is a generalized connective tissue disorder characterized by fibrosis of skin and various viscera. Natural killer (NK) cells are a subset of lymphocytes that can lyse targets without prior sensitization. Few studies have tried to assess NK cell function in patients with SSc. To evaluate NK cell cytotoxicity in patients with SSc and to see the extent of its augmentation in vitro by human interferon (hIFN) gamma in the clinical subset of limited and diffuse cutaneous diseases, we evaluated 27 patients with SSc and 22 age- and sex-matched controls by 51Cr release assay. Fifteen patients had limited cutaneous disease (mean disease duration 6.2 +/- 2.7 years) and 12 diffuse cutaneous disease (mean disease duration 5.7 +/- 2.4 years). Patients with limited SSc had significantly higher baseline NK cell function than controls (p < 0.05) and the augmentation following in vitro stimulation with hIFN gamma was negligible. Patients with diffuse SSc had lower baseline NK cell cytotoxicity than controls but this was not statistically significant. Augmentation with hIFN gamma in this group was comparable to controls. This study suggests that NK cells may have a role in the pathophysiology of this disease.

Compound heterozygosity of HLA-DR4 and DR1 antigens in Asian Indians increases the risk of extra-articular features in rheumatoid arthritis

The relationship of HLA-DR antigens in rheumatoid arthritis (RA) patients with the presence of rheumatoid factor (RF), extra-articular features, joint erosions, functional status and response to disease modifying anti-rheumatic drugs (DMARDs) was studied. Seventy-four patients with RA were serologically typed for class II antigens. Clinical features were recorded before starting DMARDs and during follow-up to assess response and side-effects. HLA-DR1 and DR4 antigens were present more frequently in patients with RA than in the general population. The presence of DR4 correlated with RF seropositivity (P < 0.001) while DR1 was associated with seronegativity (P < 0.02). Ten of the 11 patients with extra-articular features had DR1 and/or DR4. Patients with both DR4 and DR1 had a significantly higher frequency of extra-articular features compared with those with only one of these (P < 0.01). HLA-DR4 and DR1 had no relation with the presence of subcutaneous nodules, erosive changes, deformities, response to drugs and side-effects of DMARDs.

Juvenile chronic arthritis in India: is it different from that seen in Western countries?

Medical records of 89 children with juvenile chronic arthritis attending the clinical immunology outpatient department of a tertiary care hospital were analysed. Polyarticular type of juvenile chronic arthritis was the most common, followed by pauciarticular and systemic onset types. No patient with the early onset pauciarticular disease subset, which is associated with iridocyclitis and antinuclear antibody (ANA) positivity was seen. Uveitis was observed in only one patient with late onset pauciarticular disease. The ANA positivity rate (1/89) was very low. Polyarticular onset type disease had a higher incidence of deformities.

Serotonergic mechanisms in heart failure

A total of 29 subjects were studied which included 18 heart failure and 11 matched control cases. The underlying heart disease in heart failure cases was mostly chronic rheumatic valvular disease. The diagnosis of heart disease and heart failure was made on the basis of clinical examination, supplemented by electrocardiography, chest skiagram and echo cardiography. The serotonin status was assessed by measuring platelet serotonin uptake, intraplatelet serotonin content and whole blood 5-hydroxytryptamine (5-HT) levels. Blood platelet count was also done. In heart failure cases, platelet count were significantly less, the platelet 5-HT uptake and blood 5-HT levels remain unaltered. These findings indicate that platelet pool of serotonin does not contribute to raised serotonin blood levels in heart failure. The high blood serotonin levels may be due to either clearance defect or enhanced secretion from the gut or both. The altered serotonin kinetics in platelets also indicate a state of platelet activation in heart failure.

1,N6-etheno deoxy and ribo adenosine and 3,N4-etheno deoxy and ribo cytidine phosphoramidites. Strongly fluorescent structures for selective introduction in defined sequence DNA and RNA molecules

Synthesis of 1,N6-etheno-2'-deoxyadenosine, 3,N4-etheno-2'-deoxycytidine, and further chemistry on both deoxy and ribo series etheno nucleosides produces the corresponding phosphoramidites. These novel phosphoramidites are introduced selectively, quantitatively, and at specific positions at single or multiple sites into DNA or RNA sequences. The purification and chemistry involved in the synthesis of these products has been optimized to achieve the purity in excess of 99%. The resulting phosphoramidites were tested for their ability to couple and produce poly deoxy and ribonucleotides by solid phase chemistry. The coupling efficiency achieved was greater than 99% per step. Due to the instability of these etheno compounds in acidic and basic medium, various criteria to obtain pure oligomers have been established. The selective introduction of these fluorescent nucleosides into defined sequence DNA and RNA molecule will greatly facilitate the structure-function studies of various RNAs, protein-RNA structures, and DNA-RNA based diagnostics applications. The characteristic and high fluorescent intensity (detection below 1 x 10(-9) M for adenosine sites and below 1 x 10(-7) M for cytidine sites) is particularly suited for the biochemical and biological research and product development applications. The usefulness of these etheno containing modified sequences as sequencing and amplification primers is demonstrated by their full participation in polymerase chain reaction experiments.

Platelet serotonin uptake in duodenal ulcer patients

Platelet serotonin uptake was measured in 10 duodenal ulcer patients and 10 controls by determining the concentration of radioactivity in platelets after incubation with tritium-labelled serotonin binoxalate. Platelet 5-HT uptake in ulcer patients (312.0 +/- 125.0 CPM/10(7) platelets) was significantly higher than that in the control group (186.0 +/- 53.0 CPM/10(7) platelets; p < 0.01). Since the kinetics of 5-HT uptake by platelets may be a reflector of enhanced serotonergic activity, this finding may have implications in future therapeutic strategies for this disease.

Assembly of LamB and OmpF in deep rough lipopolysaccharide mutants of Escherichia coli K-12

Assembly of the OmpF and LamB proteins was kinetically retarded in deep rough lipopolysaccharide mutants of Escherichia coli K-12. OmpF assembly was affected at the step of conversion of metastable trimers to stable trimers, whereas LamB assembly was influenced both at the monomer-to-metastable trimer and metastable-to-stable trimer steps. These assembly defects were reversed in the presence of the sfaA1 and sfaB3 suppressor alleles, which were isolated by using ompF assembly mutants.

Effective control of cisplatin induced emesis by combination drug regimen

Thirty two cycles of chemotherapy were administered to sixteen patient containing 50-75 mg/msq. of cisplatin. For antiemetic prophylaxis, each patient received metoclopramide alone in the first cycle and a combination of metoclopramide + dexamethasone + lyrazepam in the next cycle. Effective control of emesis was achieved in 81% cycles on the combination antiemetic regime as compared to 19% on MCP alone. There was no statistical difference in the relief of nausea by the two regimens.

Serum IgM rheumatoid factor by enzyme-linked immunosorbent assay (ELISA) delineates a subset of patients with deforming joint disease in seronegative juvenile rheumatoid arthritis

Using human IgG as an antigen in an enzyme-linked immunosorbent assay (ELISA), we looked for the presence of IgM rheumatoid factor (RF) in the sera of 74 children with juvenile rheumatoid arthritis (JRA). Nine children had RF detectable by both latex agglutination and ELISA. Forty-five percent (26 of 65) of the children who were seronegative by latex agglutination were found to be positive for IgM RF by ELISA. The prevalence of IgM RF was higher in patients with polyarticular onset disease (57.4%) than in those with pauciarticular onset (38.5%) or systemic onset (27.2%) disease. The prevalence of RF was higher in sera from patients with deforming joint disease than those without deformities (P < 0.01).

A novel ompC mutation of Escherichia coli K-12 that reduces OmpC and OmpF levels in the outer membrane

A novel ompC mutation was isolated that not only lowered the amount of its own product, OmpC27, but also reduced the level of OmpF present in the outer membrane. ompC27 codes for a mutant OmpC protein that contains two non-native cysteine residues. The ompC27 allele confers phage resistance by lowering the level of OmpC present in the outer membrane. This effect on OmpC27 was manifested at the level of assembly as a result of disulphide bond formation between the two cysteine residues. This disulphide bonding in OmpC27 also produced a novel phenotype by specifically influencing OmpF levels. The effect of OmpC27 on OmpF was partly a result of a lowering of ompF transcription, and partly a result of an effect at the post-transcription level. The transcriptional effect is likely to be brought about by a defective membrane as a result of the insertion of the disulphide bond containing OmpC27. The post-transcriptional effect of OmpC27 on OmpF could be due to interference at the assembly level. In a dsbA::kan1 background where the in vivo disulphide bonding ability was dramatically reduced, the OmpC27-mediated effects were also curtailed.

OmpF assembly mutants of Escherichia coli K-12: isolation, characterization, and suppressor analysis

This paper describes a novel genetic method used to isolate mutations that alter proper assembly of OmpF in the outer membrane. The thermolabile nature of assembly intermediates allowed selection of temperature-sensitive mutations within the ompF gene. A variant allele of ompF (ompF-Dex) was used because it provided a convenient selectable phenotype (Dex+). Assembly mutants were isolated in two steps. First, amber mutations were obtained that mapped in ompF-Dex. This resulted in a Dex- phenotype. Starting with these Dex- strains, Dex+ revertants were isolated. Mutants that displayed a temperature-sensitive Dex+ phenotype were further characterized. Three such mutants possessed a single substitution within ompF that reverted the nonsense codon to a sense codon which replaced W214 with either an E or Q and Y231 with a Q residue in the mature OmpF protein. All three mutant OmpF proteins showed an assembly defect. This defect led to a substantial reduction in the amount of stable OmpF trimers with the concomitant increase of a high-molecular-weight form of OmpF which migrated at the top of the gel. Suppressor mutations were sought that corrected the assembly defect of OmpF. These extragenic suppressor mutations were mapped at 45 min on the Escherichia coli chromosome. The suppressor mutations displayed no allele specificity and were recessive to the wild-type allele. In the presence of a suppressor, mutant stable trimers appeared in an almost normal manner. The appearance of stable trimers concurred with a substantial loss of the high-molecular-weight OmpF species. At this stage, it is not clear whether the high-molecular-weight species of OmpF is a normal assembly intermediate or a dead-end assembly product. The results presented in this study raise the intriguing possibility of a chaperone-like activity for the wild-type suppressor gene product.

Scleromyxoedema with features of systemic sclerosis

The case is described of a patient with scleromyxoedema with features typical of systemic sclerosis. The features were so characteristic that the disease was misdiagnosed as systemic sclerosis. A brief review of the association of the two diseases is given.

Arabidopsis Acetohydroxyacid Synthase Expressed in Escherichia coli Is Insensitive to the Feedback Inhibitors

Acetohydroxyacid synthase (AHAS), the first enzyme unique to the biosynthesis of isoleucine, leucine, and valine, is the target enzyme for several classes of herbicides. The AHAS gene from Arabidopsis thaliana, including the chloroplast transit peptide, was cloned into the bacterial expression plasmid pKK233-2. The resulting plasmid was used to transform an AHAS-deficient Escherichia coli strain MF2000. The growth of the MF2000 strain of E. coli was complemented by the functional expression of the Arabidopsis AHAS. The AHAS protein was processed to a molecular mass of 65 kilodaltons that was similar to the mature protein isolated from Arabidopsis seedlings. The AHAS activity extracted from the transformed E. coli cells was inhibited by imidazolinone and sulfonylurea herbicides. AHAS activity extracted from Arabidopsis is inhibited by valine and leucine; however, this activity was insensitive to these feedback inhibitors when extracted from the transformed E. coli.

Overexpression of Acetohydroxyacid Synthase from Arabidopsis as an Inducible Fusion Protein in Escherichia coli: Production of Polyclonal Antibodies, and Immunological Characterization of the Enzyme

Acetohydroxyacid synthase (AHAS, EC 4.1.3.18) is the first enzyme unique to the biosynthesis of valine, leucine, and isoleucine. This enzyme is the target site of several classes of structurally unrelated herbicides. The conventional method of antibody production using purified protein has not been successful with this enzyme. Two separate fragments of a gene encoding a portion of the mature region of AHAS from Arabidopsis were fused with the trpE gene from Escherichia coli using the pATH1 vector. E. coli cells transformed with each respective plasmid expressed a fusion protein at levels greater than 10% of the total cell protein. The fusion protein was purified and used to immunize rabbits. Antisera obtained from the immunized rabbits immunoprecipitated AHAS activity from Arabidopsis cell free extracts. The anti-AHAS antisera reacted with a 65 kilodalton protein band in electrophoretically resolved extracts of Arabidopsis. In cross-reactivity tests, this antibody was able to immunoprecipitate AHAS activity from various plant species. Furthermore, a protein band with a molecular mass of 65 kilodaltons was detected in the crude extracts of all plant species tested on a Western blot. These results indicate that the 65 kilodalton protein represents AHAS in various plant species. The wide spectrum of cross-reactivity for the antisera supports the view that the AHAS enzyme is highly conserved across all plant species.

A genetic approach for analyzing the pathway of LamB assembly into the outer membrane of Escherichia coli

Results presented in this study demonstrate that a mutation which inserts an additional tyrosine between the 2 tyrosines at residues 118 and 119 of mature LamB protein results in a temperature-dependent assembly defect. This defect leads to the accumulation of an intermediate at the restrictive temperature that is most likely an assembly-defective monomer. These monomers are rapidly degraded in the wild type (htrA+) strain, and the biphasic kinetics of this degradation indicate that the mutation affects the assembly process and not the final product, i.e. stable trimers. In addition, our data show that the temperature-dependent assembly defect in the mutant strain is reversible, and therefore the accumulated monomers represent a true assembly intermediate. Fractionation studies show that the monomers, which can be accumulated in htrA (degP) mutants at the restrictive temperature, are associated with the outer membrane, indicating that trimerization of LamB is not a prerequisite for localization.

Nur77 is differentially modified in PC12 cells upon membrane depolarization and growth factor treatment

The rat pheochromocytoma cell line PC12 can be induced by growth factors to undergo proliferation and neuronal differentiation. These cells also have excitable membranes that can be depolarized by neurotransmitters or elevated levels of extracellular KCl. Treatment of PC12 cells with growth factors or membrane-depolarizing agents rapidly activates the expression of specific genes whose products are thought to mediate the subsequent biological responses. One such gene, nur77, is a member of the steroid and thyroid hormone receptor gene superfamily. We have identified the Nur77 protein and shown that it is synthesized rapidly and transiently in PC12 cells following stimulation, has a short half-life of 30 to 40 min, and is located in both the nucleus and the cytoplasm. Nur77 is posttranslationally modified, primarily by phosphorylation on serine residues. Phosphopeptide analysis reveals that Nur77 is modified differently upon membrane depolarization than after treatment with growth factors. We hypothesize that the activity of Nur77 is regulated by both differential gene expression and posttranslational modification and that these modes of regulation contribute to distinct downstream responses specific to membrane depolarization and growth factor treatment.

Occurrence of systemic autoimmune disorders & autoantibodies in house-hold contacts of patients with systemic lupus erythematosus

Household contacts of 22 randomly selected patients with systemic lupus erythematosus (SLE) were screened for autoimmune diseases and autoantibodies. Thirty nine consanguineous and 17 nonconsanguineous household contacts were studied. In the first group symptomatic SLE was seen in 5 per cent, rheumatoid arthritis in 2.5 per cent, antinuclear antibody (ANA) in 10 per cent and rheumatoid factor (RF) in 5 per cent while anti-dsDNA, anti-nRNP and anti-Sm antibodies were not detected in any individual. The second group showed total absence of any marker of autoimmunity. In normal controls only RF was detected in 3 per cent. The occurrence of markers of autoimmunity only in consanguineous household contacts of patients with SLE further confirms the recognised role of genetic factors in the etiology of SLE.

Effects of commonly used NSAID's on gastric mucosa. A clinico-endoscopic and histopathological study

Non steroidal anti-inflammatory drugs (NSAID's) are one of the most commonly used agents in clinical practice today. All these drugs are known to produce gastro-intestinal lesions. In the present study we found that aspirin, indomethacin and phenylbutazone caused gastric mucosal damage in 90.9%, 100%, respectively while ibuprofen and paracetamol caused gastric mucosal damage in 33.3% and 37.5% respectively. Thus latter two drugs were safer NSAID's. Further more we have demonstrated that endoscopic monitoring of the patients on NSAID's is a sensitive method of early detection of gastric mucosal damage. This monitoring may be particularly valuable in high risk subjects on NSAID's.