Plasma interleukin-6, tumour necrosis factor alpha and blood cytokine production in type 2 diabetes

Type 2 diabetes is associated with increased circulating concentrations of markers of the acute-phase response and interleukin-6 (IL-6). An augmented acute-phase response may be a mechanism which explains many of the clinical and biochemical features of type 2 diabetes and its complications. We sought to confirm that circulating concentrations of the cytokine acute-phase mediators IL-6 and tumour necrosis factor alpha [TNFalpha] are elevated in type 2 diabetes, and investigated blood as a source of cytokines in type 2 diabetes. Blood samples from 20 type 2 diabetic and 17 age-matched healthy subjects were incubated in vitro for 24 hr with and without lipopolysaccharide (LPS) stimulation and secreted cytokines measured. Plasma IL-6 and TNFalpha were significantly increased in type 2 diabetes compared to normal subjects. However, basal production of IL-6 and TNFalpha in cultured diabetic blood was markedly depressed in comparison with non-diabetic samples. IL-6 and TNFalpha production was increased in blood in response to LPS, reaching similar levels in diabetic and non-diabetic subjects, though IL-6 was slightly but significantly higher in controls. We conclude that circulating levels of IL-6 and TNFalpha are increased in type 2 diabetes but there is downregulation of basal cytokine production in blood cells in type 2 diabetes. Blood has the capacity to produce cytokines in diabetes which contribute to the augmented acute-phase response, but the main source of the increased plasma IL-6 and TNFalpha concentrations may be from non-circulating cells.

Completeness of excision and follow up cytology in patients treated with loop excision biopsy

AIMS

To assess the relation between the grade and the status of follow up cytology, the completeness of loop excision biopsies with cervical intraepithelial neoplasia (CIN), and the findings at follow up cytology, as well as the differences between complete and incomplete exclusion, using the odds ratio. Treatment failure was assessed.

METHODS

1600 women with CIN (290 CIN1, 304 CIN2, 1006 CIN3) were followed for a minimum of six months and a maximum of 10 years. A database was created and comparisons performed. The mean age of the patients was 37 years.

RESULTS

Excision was complete in over 84% of loops. Residual disease and recurrence of high grade dyskaryosis was more common in women with CIN 3 than CIN 2 or 1. No high grade dyskaryosis was seen in the fifth follow up smear in patients with CIN 1 and CIN 2. Residual, recurrent, and persistent disease was most common in patients with incompletely excised CIN at ectocervical and endocervical margins and deep margins of resection than in patients with completely excised CIN. The odds ratios were significantly higher in the women who had incomplete excision of CIN at ectocervical, endocervical, both ecto- and endocervical, and deep margins of resection compared with those with apparent complete excision of CIN lesions. One patient developed invasive squamous cell carcinoma 44 months after loop excision which showed CIN 3 invading endocervical crypts and extending to both ectocervical and endocervical margins of resection.

CONCLUSIONS

At long term follow up, patients with CIN who have residual disease are at increased risk of persistent disease and should therefore be followed up regularly with cytology and colposcopy. The findings support national policy of returning women with treated CIN of any grade to normal recall after five years except for cases of CIN3 where excision was incomplete or equivocal. In these cases follow up with annual smear for 10 years is recommended.

Binding of paxillin to alpha4 integrins modifies integrin-dependent biological responses

The alpha4 integrins are indispensable for embryogenesis, haematopoiesis and immune responses, possibly because alpha4 regulates cellular functions differently from other integrins through its cytoplasmic tail. We used novel mimics of the alpha4 tail to identify molecules that could account for alpha4-specific signalling. Here we report that the alpha4 tail, but not several other alpha-subunit tails, binds tightly to the signalling adaptor paxillin. Paxillin physically associated with alpha4 integrins in Jurkat T cells at high stoichiometry, and joining the alpha4 tail to alphaIIb resulted in a complex of integrin alphaIIbbeta3 with paxillin. This association markedly enhanced the rates of alphaIIbbeta3-dependent phosphorylation of focal adhesion kinase and cell migration. It also reduced cell spreading, focal adhesion and stress fibre formation. A point mutation within the alpha4 tail that disrupts paxillin binding reversed all of these effects. Furthermore, alpha4beta1-dependent adhesion to VCAM-1 led to spreading of mouse embryonic fibroblasts derived from paxillin-null but not from wild-type mice. Thus, the tight association of paxillin with the alpha4 tail leads to distinct biochemical and biological responses to integrin-mediated cell adhesion.

The application of a linear algebra to the analysis of mutation rates

Cells and bacteria growing in culture are subject to mutation, and as this mutation is the ultimate substrate for selection and evolution, the factors controlling the mutation rate are of some interest. The mutational event is not observed directly, but is inferred from the phenotype of the original mutant or of its descendants; the rate of mutation is inferred from the number of such mutant phenotypes. Such inference presumes a knowledge of the probability distribution for the size of a clone arising from a single mutation. We develop a mathematical formulation that assists in the design and analysis of experiments which investigate mutation rates and mutant clone size distribution, and we use it to analyse data for which the classical Luria-Delbrück clone-size distribution must be rejected.

Evaluation of transcriptional fusions with green fluorescent protein versus luciferase as reporters in bacterial mutagenicity tests

A bacterial plasmid was constructed on which the regulatory region of the umuC gene of Escherichia coli was fused to the coding sequence of the green fluorescent protein gene (gfp) from the jellyfish Aequorea victoria. Escherichia coli AB1157 strains carrying the plasmid emitted fluorescence in the presence of mutagens that induce the SOS DNA repair system. Data on tests with nitrosoguanidine, methylmethane sulphonate and UV radiation (254 nm) are presented. Although fluorescent detection using this system was not as rapid or sensitive as a similar luminescent equivalent (umuC-luxAB), the gfp reporter system was more robust. Escherichia coli umu gene induction was also analysed in Salmonella typhimurium TA1537 cells following plasmid transfer and exposure to the same range of mutagens. There was no significant difference in sensitivity between the two species. These preliminary results will provide the basis for development of mutagenicity test systems useful in the testing of complex mixtures, such as environmental samples, and the investigation of physiological parameters influencing spontaneous mutagenesis in bacteria.

Preponderance of hypokalaemia as a cause of acute onset quadriparesis in northern India/southern Nepal

Of 68 patients who were admitted with acute quadriparesis to a hospital in northern India, over 70% were found to be hypokalaemic. The most common cause of hypokalaemia was that associated with gastroenteritis (54%). These patients had all received intravenous fluids previously. It is likely that their hypokalaemia was caused by gastrointestinal loss compounded by parenteral fluid replacement. The next most common group of hypokalaemia-associated quadriparesis had no obvious cause for hypokalaemia (38%). Hypokalaemia-induced quadriparesis is a potentially life-threatening illness which can be readily treated with potassium supplements. The physician should consider hypokalaemia in patients who present with acute onset quadriparesis, and even if diagnostic tests for hypokalaemia are not available, should consider a judicious trial of potassium supplementation empirically, provided that there are no contraindications.

Vascular surgical society of great britain and ireland: RETA: the registry of endovascular treatment of abdominal aortic aneurysms

BACKGROUND: RETA is a voluntary registry within the UK established as a joint venture between radiologists and surgeons. The aim is to evaluate carefully the endovascular treatment of abdominal aortic aneurysms during introduction into clinical practice. METHODS: Some 367 patients have been included in the registry from 23 centres since its inception on 1 January 1996. In the majority (82 per cent) an elective repair was performed for an asymptomatic aneurysm. The mean age of the patients was 71.9 years and 28 per cent were deemed unsuitable for conventional repair. One hundred and ninety-nine bifurcated (54 per cent), 18 tube (5 per cent) and 148 aortouni-iliac with crossover (40 per cent) stent graft types were placed. RESULTS: At the end of the procedure 77 per cent of aneurysms were excluded with no complications. Twenty-one patients (6 per cent) required conversion to open repair. Forty-four (12 per cent) required additional endovascular procedures. At 30 days 87 per cent of the aneurysms were excluded or repaired. The 30-day mortality rate was 7 per cent (n = 24) with a significant improvement between 1996 and 1997, from 11 to 4 per cent. There were 25 persistent leaks (7 per cent). The death rate was related to the fitness of patient, device used and requirement for conversion. One-year follow-up data are available for 140 patients. There have been 13 deaths (9 per cent), three ruptures (2 per cent) and some form of complication in 20 per cent of cases overall. CONCLUSION: Improving results have been demonstrated for the primary procedure. At present there is a relatively high complication rate and ruptures have occurred. Rigorous continued follow-up is required.

Vascular surgical society of great britain and ireland: avoiding the complications of thrombolysis

BACKGROUND: NATALI is a voluntary database of patients undergoing peripheral vascular thrombolysis run on behalf of the Thrombolysis Study Group. The size of the data set allows analysis to identify predictors of outcome and complications. These may be patient factors or variables related to the technique used. METHODS: Since its inception on 1 January 1990, 798 thrombolytic events have been recorded. Details are collected on a wide range of factors: perceived risk factors; details of thrombolysis technique; complications; outcome; and adjunctive procedures. Using univariate and multivariate analysis, factors associated with an increased risk of complications were investigated. RESULTS: Death and complications (perilysis) occurred in 25.9 per cent of episodes (n = 207). Patient factors were the main influence on the risk of complications. Increasing age, use of aspirin and thrombolysis of grafts were significantly associated with an increased risk of complications after adjustment for confounders (P < 0.05). Female sex, the presence of peripheral vascular disease and Fontaine class were of borderline significance. Other patient factors were not associated with an increased risk of complication. Aspects of radiological technique, such as agent used, sheath size, length of lysis, dose of lysis, use of heparin or adjunctive procedures, had no relationship to the rate of complications. CONCLUSION: Case selection is the most important factor influencing the occurrence of complications. Radiological technique does not seem to influence the occurrence of complications.

Regulation of early events in integrin signaling by protein tyrosine phosphatase SHP-2

The nontransmembrane protein tyrosine phosphatase SHP-2 plays a critical role in growth factor and cytokine signaling pathways. Previous studies revealed that a fraction of SHP-2 moves to focal contacts upon integrin engagement and that SHP-2 binds to SHP substrate 1 (SHPS-1)/SIRP-1alpha, a transmembrane glycoprotein with adhesion molecule characteristics (Y. Fujioka et al., Mol. Cell. Biol. 16:6887-6899, 1996; M. Tsuda et al., J. Biol. Chem. 273:13223-13229). Therefore, we asked whether SHP2-SHPS-1 complexes participate in integrin signaling. SHPS-1 tyrosyl phosphorylation increased upon plating of murine fibroblasts onto specific extracellular matrices. Both in vitro and in vivo studies indicate that SHPS-1 tyrosyl phosphorylation is catalyzed by Src family protein tyrosine kinases (PTKs). Overexpression of SHPS-1 in 293 cells potentiated integrin-induced mitogen-activated protein kinase (MAPK) activation, and potentiation required functional SHP-2. To further explore the role of SHP-2 in integrin signaling, we analyzed the responses of SHP-2 exon 3(-/-) and wild-type cell lines to being plated on fibronectin. Integrin-induced activation of Src family PTKs, tyrosyl phosphorylation of several focal adhesion proteins, MAPK activation, and the ability to spread on fibronectin were defective in SHP-2 mutant fibroblasts but were restored upon SHP-2 expression. Our data suggest a positive-feedback model in which, upon integrin engagement, basal levels of c-Src activity catalyze the tyrosyl phosphorylation of SHPS-1, thereby recruiting SHP-2 to the plasma membrane, where, perhaps by further activating Src PTKs, SHP-2 transduces positive signals for downstream events such as MAPK activation and cell shape changes.

Perceptions of cancer and its causes among "Industrial Corridor" residents: the LMRICS Planning Project. Lower Mississippi River Interagency Cancer Study

The Industrial Corridor is composed of 11 parishes heavily concentrated with petrochemical facilities along the Mississippi River from Baton Rouge to the mouth of the river. There exists a generalized belief that the proximity of these waste-emitting industries to residential areas has adversely impacted the health of the residents including increasing the rates of cancer. At the same time, Louisiana Tumor Registry data do not support the widely held belief of excess cancer rates in the corridor. A community in the corridor was chosen to explore the issues of health beliefs, health-seeking behavior, and perceived quality of life. An extensive questionnaire was developed and administered to a sample of community residents. The results of the questionnaire suggest there may be multiple factors that influence the perceived well-being and preventive health practices of corridor residents.

Characterization of a focal adhesion protein, Hic-5, that shares extensive homology with paxillin

Paxillin is a focal adhesion scaffolding protein which was originally identified as a substrate of the oncogenic tyrosine kinase, v-src. Paxillin has been proposed to be involved in regulation of focal adhesion dynamics. Two alternatively spliced mouse paxillin cDNAs were cloned and in the process, a paxillin-related protein, Hic-5, was also identified. Cloning and characterization of Hic-5 indicates that this protein shares extensive homology with paxillin. Although Hic-5 was originally characterized as a TGF-beta-inducible gene and proposed to be a transcription factor involved in senescence, the studies here demonstrate that Hic-5 is localized to focal adhesion in REF52 cells and can interact with the focal adhesion proteins, Fak, Frnk, and vinculin. In addition, like paxillin, Hic-5 can bind to a negative regulator of Src PTKs, csk but does not bind to the adaptor protein Crk. Like paxillin, localization of this protein to focal adhesions is mediated primarily by the LIM domains; however, sequences outside the LIM domains also play a minor role in focal adhesion targeting. These results suggest that Hic-5 like paxillin could be involved in regulation of focal adhesion dynamics and raise the possibility that Hic-5 and paxillin could have overlapping or opposing functions in the overall regulation of cell growth and differentiation.

Genomics: the implications for ethics and education

Over the past 10 years, the identification of disease genes has been expanding rapidly. Those identified in the earlier part of the decade were largely achieved through positional cloning and the majority are for relatively rare disorders which involve single genes. As the Human Genome Mapping Project has progressed, the rate of gene discovery has increased substantially through the development of new DNA sequencing techniques and in silico approaches. The human genome will have been largely sequenced by ther Spring 2000. We can expect the identification of large numbers of susceptibility genes for common multifactorial polygenic diseases as well as genes which are associated with human behavioural traits. Some of these advances hold out the prospects of real progress in the diagnosis and treatment of a wide range of disorders. However, for many individuals, increased knowledge about their genes will present ethical dilemmas which are difficult to resolve. There are also wider ethical issues which concern the use of genetic information by insurers and employers and yet others which concern ownership and access. In this chapter, the main ethical issues raised by the impact of genomics on healthcare are discussed. The role of education in enabling individuals and health professionals to meet these challenges is also considered.

Preclinical studies on suicide gene therapy for head/neck cancer: a novel method for evaluation of treatment efficacy

BACKGROUND

Malignancies of the oral cavity and oropharynx account for 31% of all diagnosed cancers in India. In most cases, patients present with tumours that are clinically stage III/IV where surgery, radiotherapy and chemotherapy have not been very effective. Hence, there is an urgent need for alternate treatment modalities. Gene therapy is a recent development shown to be effective in various malignancies. In this study we have attempted to cause bulk reduction in tumour volume using the HSVtk/ganciclovir strategy, solely on the basis of the 'bystander' effect.

METHODS

Nude mouse xenograft tumours of human head/neck cancer were engrafted with cells expressing viral thymidine kinase. After treatment with 8 mM ganciclovir for 14 days, the treatment efficacy was monitored. A novel method has been devised to evaluate cell kill microscopically in the whole tumour.

RESULTS

Of the 11 mice included in the study, 9 showed a significant reduction in total tumour volume of treated versus control tumours (p = 0.015).

CONCLUSIONS

Bulk reduction in tumour load can be brought about without use of viral vectors for gene transfer solely by the bystander effect.

Operation of mixed-culture immobilized cell reactors for the metabolism of meta- and para-nitrobenzoate by comamonas sp. JS46 and comamonas sp. JS47

The treatment of meta- and para-nitrobenzoic acid in an industrial wastestream by Comamonas sp. JS46 and Comamonas sp. JS47 is investigated. The most important feature of the wastestream is the constantly changing concentration ratio of the two isomers. The most extreme occurrence is considered here: the complete change in feed carbon source from one isomer to the other. A series of immobilized cell airlift reactor experiments are described to examine the operation and response of the system to these changes in the feed carbon source. Separate reactors containing each species immobilized are compared with a reactor containing both species immobilized within the same bead, and to a reactor containing both species with each species confined to separate beads. On the basis of response time necessary to recover the appropriate activity, the reactor containing both species immobilized within the same bead offers the most effective arrangement. Interactions occurring between the two organisms in the coimmobilized system, mediated by the nitrobenzoate metabolites, are discussed relative to the improved response of this arrangement. Copyright 1998 John Wiley & Sons, Inc.

Update on endovascular management of arterial occlusive disease

Although balloon angioplasty is the most widely used technique for treating peripheral vascular disease, developments in endovascular therapies have extended methods of percutaneous vascular intervention. Lasers have been used to recanalize occluded arteries. Mechanical devices can remove obstructions and metallic stents can be placed to keep a vessel open with good long-term patency.

Continuous culture dynamics for aniline metabolism by Pseudomonas sp. CIT1

Inhibition by toxic substrates enables multiple steady states to arise in biodegradation systems. This phenomenon was investigated for the continuous metabolism of aniline by Pseudomonas sp. CIT1. Differences of various metabolic parameters between the two growth regimes (uninhibited and inhibited) and the transient response to a step-up in dilution rate were determined. Regulatory mechanisms consistent with the experimental evidence are proposed. Aniline is the transcriptional inducer of a metabolic pathway that converts aniline to TCA cycle intermediates. The suite of enzymes is coordinately expressed from a single promoter. We followed the level of the pathway mRNA using a fragment containing the catechol 2,3 dioxygenase gene (andioxB) and monitored the pathway enzyme activity using catechol 2,3 dioxygenase (C23D). The inhibited regime resulted in a 60% lower growth yield, near constant levels of C23D monomer, but a 50% reduction in the specific activity of C23D, increased RNA synthesis rates (total and aniline pathway mRNA), and elevated RNA decay rates. Elucidation of regulatory mechanisms indicates that C23D is noncompetitively inhibited by aniline and subject to feedback inhibition by 2-hydroxymuconic semialdehyde (HMS). During uninhibited growth regime operation, metabolism of HMS is the rate-limiting step; in contrast, conversion of aniline to catechol limits growth in the inhibited regime.

Trends in the use of pelvimetry techniques

Assessment of maternal pelvic dimensions is usually considered necessary where vaginal delivery is contemplated in a breech presentation or if reduced pelvic dimensions are suspected in a current or previous pregnancy. Pelvimetry techniques include computed tomography (CT), conventional radiography, digital fluorography and magnetic resonance imaging (MRI). The first three techniques result in a radiation dose to mother and fetus which, depending on how the technique is performed, can vary by up to 40-fold. Of the techniques using X-rays, CT pelvimetry with a lateral scanogram generally gives the lowest radiation dose and conventional radiography using an air gap technique with a single lateral view is a relatively low-dose alternative where CT is not available. A questionnaire was sent to 227 hospitals during 1993 and 1996 to assess whether there was a move towards lower dose techniques of pelvimetry. The results show a trend away from conventional pelvimetry (48.4% in 1993 to 28% in 1996) with a small proportion of centres using MRI (4%) in 1996. Of the centres still using conventional pelvimetry, relatively few were using a low-dose air-gap technique (2.1% in 1993 to 10.9% in 1996). An increasing majority of centres were using one-view CT (69.3% in 1993 and 80.4% in 1996) but a significant proportion were still performing more than one view. This study shows that there was a move towards lower dose techniques of pelvimetry but that there were still many hospitals that had not implemented a policy of reducing radiation exposure in these patients.

Construction of a umuC'-luxAB plasmid for the detection of mutagenic DNA repair via luminescence

This paper describes a novel system for the detection of mutagenic DNA repair in Escherichia coli. The DNA damage inducible umuC gene of Escherichia coli has been fused to the luxAB genes from Vibrio harvleyi that encode the enzyme luciferase. Mutagenicity has been assessed semi-quantitatively by the induction of bioluminescence. This system is simple, rapid and equivalent in sensitivity to other currently available test procedures. Its use in the detection of known SOS mutagens MMS, MNNG and UV is described.

Cellular functions regulated by Src family kinases

Src family protein tyrosine kinases are activated following engagement of many different classes of cellular receptors and participate in signaling pathways that control a diverse spectrum of receptor-induced biological activities. While several of these kinases have evolved to play distinct roles in specific receptor pathways, there is considerable redundancy in the functions of these kinases, both with respect to the receptor pathways that activate these kinases and the downstream effectors that mediate their biological activities. This chapter reviews the evidence implicating Src family kinases in specific receptor pathways and describes the mechanisms leading to their activation, the targets that interact with these kinases, and the biological events that they regulate.

Activation of extracellular signal-regulated kinases (ERK1/2) by angiotensin II is dependent on c-Src in vascular smooth muscle cells

Among the angiotensin II (Ang II)-mediated signal events likely to be important in vascular smooth muscle cells (VSMCs) is activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). The upstream mediators by which Ang II activates ERK1/2 remain poorly defined. Recently, we showed that Ang II activated c-Src, a nonreceptor kinase, which is a candidate to mediate Ang II signal events. To determine whether c-Src is required for ERK1/2 activation by Ang II, we studied the effects of Src family-selective tyrosine kinase inhibitors on ERK1/2 activation and also studied Ang II-mediated signal events in Src-deficient and Src-overexpressing VSMCs. The tyrosine kinase inhibitors, genistein and CP-188,556, blocked Ang II-mediated ERK1/2 activation in rat VSMCs (rVSMCs). We derived Src-deficient VSMCs from the aortas of c-Src knockout mice (Src-/- mVSMCs). Basal ERK1/2 activity was lower, and activation of ERK1/2 by Ang II was significantly decreased in Src-/- mVSMCs compared with wild-type mVSMCs, whereas ERK1/2 protein expression and ERK1/2 activation by phorbol 12-myristate 13-acetate were similar. To examine the role of c-Src further, we overexpressed wild-type or dominant-negative c-Src in rVSMCs using retroviral vectors. ERK1/2 activation by Ang II was significantly increased in rVSMCs that overexpressed c-Src, whereas ERK1/2 activation by Ang II was significantly inhibited in rVSMCs that overexpressed dominant-negative c-Src compared with control rVSMCs. These findings demonstrate that c-Src activation is required for Ang II stimulation of ERK1/2 in VSMCs and suggest an important role for c-Src in Ang II-mediated signal transduction.