134 Quantitative Assessment of Visual Function for Pituitary Macroadenomas: A Practical Scoring Algorithm

Introduction

There is a myriad of existing terms by which visual capacity is recorded. The lack of a standardised categorisation of observations commonly results in ambiguities. We report the utility of a visual function score (VFS) in patients managed by transsphenoidal surgery.

Method

A VFS (expressed as a percentage) with a maximum score of 20 was calculated for each eye using the Snellen VA (40% weighting: score 0-8) and Humphrey Allergan 30-2 automated visual field (60% weighting: score 0-12).

Results

280 patients (560 eyes) underwent transsphenoidal pituitary adenoma resections with complete pre- and post-operative visual function assessment. Mean age 56 years; 56.4% male. 26.1% were treated by endoscopic technique and 73.9% were treated by microscopic technique. Pre-operative vision was normal in 38.0% eyes. All these had full post-operative vision. In patients with pre-operative visual loss (347 eyes), the mean pre-operative VFS rose from 70.8% to 87.5% post-operatively. 43.8% eyes attained full post-operative vision, 28% improved, and 25.6% remained unchanged. 9 patients (2.6%) had worse immediate post-operative vision.

Conclusions

The VFS is a convenient single measure of visual function that may facilitate local and national audit of transsphenoidal surgery. Studies are planned to correlate this with patient reported visual quality of life measures.

[Peripheral nerve stimulation effectiveness in the upper limb function recovery of patients with a stroke sequel: systematic review and meta-analysis]

INTRODUCTION

In 30-66% of the cases, people who survive a stroke suffer from an affected non functional upper limb. Somatosensory stimulation might positively influence the muscular activity of patients with motor deficiencies caused by a stroke.

AIM

To carry out a systematic review and a meta-analysis of the effectiveness of peripheral nerve stimulation (PNS) use in the improvement of the plegic/paretic upper limb function in patients with a stroke sequel.

SUBJECTS AND METHODS

Randomized and non randomized clinically controlled tests and crossover studies published until November 2014 in Medline electronic database, Cochrane Central Register of Controlled Trials, LILACS, SciELO and Open Grey were included. Studies at high risk of bias were excluded. Two independent researchers assessed the studies' eligibility criteria and retrieved and analyzed all data.

RESULTS

A total of 1,967 studies were found, five of them were included for data retrieval and analysis, using a risk of bias fashion of 6/10 at the PEDro scale. 224 patients were included, 95 of them received PNS in multiple modalities and 129 received other interventions as a control group.

CONCLUSION

The analyzed data suggest that the function of the plegic/paretic upper limb improves after the application of PNS either with or without functional training. On the other hand, the meta-analysis result indicates that there is still insufficient evidence to guarantee the effectiveness of PNS use for the recovery of the plegic/paretic upper limb function in patients with a stroke sequel.

Acute bilateral leg amputation following combat injury in UK servicemen

BACKGROUND

This study aims to characterise the injuries and surgical management of British servicemen sustaining bilateral lower limb amputations.

METHODS

The UK Military Trauma Registry was searched for all cases of primary bilateral lower limb amputation sustained between March 2004 and March 2010. Amputations were excluded if they occurred more than 7 days after injury or if they were at the ankle or more distal.

RESULTS

There were 1694 UK military patients injured or killed during this six-year study period. Forty-three of these (2.8%) were casualties with bilateral lower limb amputations. All casualties were men with a mean age of 25.1 years (SD 4.3): all were injured in Afghanistan by Improvised Explosive Devices (IEDs). Six casualties were in vehicles when they were injured with the remaining 37 (80%) patrolling on foot. The mean New Injury Severity Score (NISS) was 48.2 (SD 13.2): four patients had a maximum score of 75. The mean TRISS probability of survival was 60% (SD 39.4), with 18 having a survival probability of less than 50% i.e. unexpected survivors. The most common amputation pattern was bilateral trans-femoral (TF) amputations, which was seen in 25 patients (58%). Nine patients also lost an upper limb (triple amputation): no patients survived loss of all four limbs. In retained upper limbs extensive injuries to the hands and forearms were common, including loss of digits. Six patients (14%) sustained an open pelvic fracture. Perineal/genital injury was a feature in 19 (44%) patients, ranging from unilateral orchidectomy to loss of genitalia and permanent requirement for colostomy and urostomy. The mean requirement for blood products was 66 units (SD 41.7). The maximum transfusion was 12 units of platelets, 94 packed red cells, 8 cryoprecipitate, 76 units of fresh frozen plasma and 3 units of fresh whole blood, a total of 193 units of blood products.

CONCLUSIONS

Our findings detail the severe nature of these injuries together with the massive surgical and resuscitative efforts required to firstly keep patients alive and secondly reconstruct and prepare them for rehabilitation.

A Phenotype-Based Model for Rational Selection of Novel Targeted Therapies in Treating Aggressive Breast Cancer

BackgroundGlobal transcriptional profiling has facilitated breast cancer research, and has led to analyses of breast cancer phenotypes and clinical outcomes. While gene expression signatures can identify patients with aggressive tumors who require chemotherapy, data that guide drug selection are relatively sparse, generally obtained in clinical trials that treat patients with standard therapies and often limited by small study size. We propose a method that incorporates genomic and in vitro and in vivo preclinical testing of patient tumors to identify optimal and novel therapeutic regimens for individual breast tumors.Methods and FindingsNine independent microarray datasets comprised of 1,723 breast cancer cases were used in a meta-analysis to examine patterns of drug sensitivity predictions. Drug sensitivity signatures were developed based on the Broad Institute Connectivity Map, and applied using binary regression to individual tumor gene expression data. These analyses provide probabilities for each individual tumor's sensitivity to specific drugs, and allows us to identify patterns of drug sensitivity for unique breast cancer phenotypes. We found consistent patterns of drug sensitivity that were specific to individual tumor subtypes. Notably, we discovered that over 80% of basal-like breast cancers were predicted to respond to inhibitors of the phosphatidylinositol 3-kinase pathway and that normal-like tumors were most likely to respond to a heat shock protein 90 inhibitor. Among the more aggressive breast cancer phenotypes, there was a high predicted response to valproic acid (VPA), a histone deacetylase inhibitor. Using a subset of targeted therapeutics that are currently in clinical trials with solid tumors and for which we have drug response signatures, we performed in vitro drug testing on a panel of 18 breast cancer cell lines and found significant correlation between predicted and actual drug sensitivity. Additionally, predicted sensitivity to VPA for specific patient breast tumors was confirmed in vitro and in vivo, using 3-D primary cell culture and orthotopic xenografts generated from the same human tumors for which the predictions were made. These studies highlight VPA as an effective therapy for aggressive breast cancer tumors, and underscore the suitability of our genomic approach to identify optimal targeted therapeutic strategies for women with breast cancer.ConclusionsWe provide a drug sensitivity prediction model using primary tumor gene expression profiles and offer preclinical examples of drug response based on this model. This approach can be used to personalize drug therapy for patients with breast cancer. This will hopefully improve clinical responses for patients while sparing them toxicity from agents that will have no effect on their tumors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2007.

Varying gender pattern of childhood injury mortality over time in Scotland

OBJECTIVE

This article explores gender in relation to Scottish child injury mortality over time.

DESIGN

Injury mortality data for children aged 0-14 years in Scotland were obtained from the General Register Office for Scotland. The study period was 1982-2006 inclusive. Data were analysed in terms of age, gender, year of death and cause of death. Age-adjusted injury mortality rates, male:female (m:f) ratios and temporal trends were calculated.

SETTING

Scotland, UK.

SUBJECTS

Children, aged 0-14 years, resident in Scotland, who died from injury during the study period.

RESULTS

There was an overall significant male excess (m:f ratio 1.70). Boys were significantly more likely to die from injuries in all age groups except infancy (m:f ratio 1.20, 1.32, 2.09, 2.09 in age groups <1, 1-4, 5-9 and 10-14 years). For childhood as a whole, the most gender-related fatal injury causes were poisoning (m:f ratio 3.21), falls (m:f ratio 2.75), suicide (m:f ratio 2.19), drowning and suffocation (m:f ratio 2.09), pedestrian (m:f ratio 1.72) and road traffic injuries (m:f ratio 1.65). The only cause that did not show a significant m:f ratio was fire. The male excess declined markedly over time.

CONCLUSION

The gender pattern of child injury mortality in Scotland is highly variable and changing over time to the point where the previous male excess has almost disappeared in some age and cause categories. The overall male excess in child injury mortality has, however, remained consistent over time although the trend is downwards and converging. These findings are largely unexplained.

The Archaeotools project: faceted classification and natural language processing in an archaeological context

This paper describes 'Archaeotools', a major e-Science project in archaeology. The aim of the project is to use faceted classification and natural language processing to create an advanced infrastructure for archaeological research. The project aims to integrate over 1 x 10(6) structured database records referring to archaeological sites and monuments in the UK, with information extracted from semi-structured grey literature reports, and unstructured antiquarian journal accounts, in a single faceted browser interface. The project has illuminated the variable level of vocabulary control and standardization that currently exists within national and local monument inventories. Nonetheless, it has demonstrated that the relatively well-defined ontologies and thesauri that exist in archaeology mean that a high level of success can be achieved using information extraction techniques. This has great potential for unlocking and making accessible the information held in grey literature and antiquarian accounts, and has lessons for allied disciplines.

Immunotherapy with MUC1/CEA vaccine alone or combined with chemotherapy in patients with metastatic breast cancer

Abstract #4123

Background: PANVAC is a recombinant pox viral vaccine that contains transgenes for the tumor-associated antigens (TAAs), MUC1 and CEA. PANVAC also contains three T-cell co-stimulatory molecules (B7.1, LFA-3, ICAM-1) to enhance immune response. Clinical studies with a similar vaccine have shown docetaxel does not diminish specific T-cell responses to the TAAs delivered in the pox viral vaccines. We are evaluating the use of PANVAC in two ongoing trials in patients with metastatic breast cancer.&#x2028; Methods: The primary end point of these two phase II trials is progression-free survival (PFS). As secondary end point specific T-cell response is measured using ELISPOT assay in HLA-A2 patients. One study uses vaccine alone, given monthly by SC injections and is accompanied by 4 days of low dose GM-CSF. The other trial randomizes to either vaccine + docetaxel or docetaxel alone; giving the same V regimen (as the first study) on day 1 followed by docetaxel at 35 mg/m2 on days 2, 9, and 16 of each 28 day cycle. The chemotherapy alone arm uses the same docetaxel dosing.&#x2028; Results: Twenty three patients have been accrued with a median age of 57.6 (31-75) years. Sixteen patietns had ER/PR+ tumors. The patients had a median of 4 (0-6) previous chemotherapy regimens; their median time since their last chemotherapy was 2 months with a 10th – 90th percentile of 1-8 months. Vaccine is well tolerated with few grade 3 and no grade 4 adverse events. Most of the grade 1-2 toxicities were self-limited site reactions and flu-like symptoms. Three of 13 patients on vaccine alone study have shown measurable clinical benefits. Two were on study for 6 months, of whom one had significant improvement in pain with reduction in vertebral lesions on MRI; another had a sustained &gt;20% decrease in bulky liver metastases. A third patient on vaccine alone was on study for 9 months with reduction in her mediastinal lymphadenopathy. Of the 6 patients who received vaccine + docetaxel, 5 had measurable disease. One achieved PR by RECIST criteria and remained on study for 19 months; another had a 50% reduction in the diameter of a chest wall lesion. A third patient with bone only disease was on study for 12 months with significant improvements on her bone scan.&#x2028; Conclusions: Vaccine given alone or in combination with docetaxel is shown to be safe in patient with metastatic breast cancer. There is preliminary evidence that there may be some clinical benefit from vaccine alone as well as its combination with chemotherapy. Confirmation of these results and PFS determination requires additional patient enrollment and follow up in both studies. Furthermore, immunologic studies including functional analysis of CD4 and CD8 T-cells will be performed to help elucidate the immune responses these regimens may elicit.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4123.

Intentional injury mortality in the European Union: how many more lives could be saved?

OBJECTIVE

To explore the scope for reducing the number of intentional injury deaths, hypothesizing that all European Union (EU) countries are able to match the experience of the country with the lowest mortality rate for intentional injuries.

DESIGN

Intentional injury mortality data for the three last available years and denominator population estimates were obtained from the World Health Organisation mortality database for the 22 EU countries with more than one million population. To estimate the potential saving of lives, the yearly average age adjusted injury mortality rates were calculated. This issue done for children (0-14), adults (15-64), and elderly people (65 and over), both including and excluding deaths from undetermined cause.

MAIN OUTCOME MEASURES

Number of lives that might potentially be saved if all EU member states matched the lowest intentional injury rate reported by an EU member state.

RESULTS

Over 73% of all intentional injury deaths could have been avoided if all EU countries matched the country with the lowest intentional injury mortality rate. EU member states would have suffered about 600 fewer intentional injury deaths in children, about 40 000 fewer adult deaths, and over 14 000 fewer intentional injury deaths in the elderly. This amounts to over 55 000 lives in a single year.

CONCLUSIONS

Many lives lost through injury might be saved if all countries were to achieve the lowest intentional injury mortality rates reported in the EU. How this theoretical observation might be translated into practice needs to be further explored as the international variation in intentional injury mortality rates in the EU results from a range of factors.

Consistency in regional trends of aggressiveness in cancer care near the end of life for elderly Americans, 1991–2000

6004

Background: We have previously developed and reported on performance measures assessing the aggressiveness of cancer treatment near the end of life for selected cancers during 1993–96. Methods: We compared the care delivered in the 77 Health Care Service Areas (HCSAs) monitored by the Surveillance, Epidemiology, and End Results (SEER) program to all Medicare-eligible patients aged 65 and over who died of cancer (any diagnosis) between 1991 and 2000. We used hierarchical regression models to estimate regional variation in both levels and trends of each indicator. We then ranked each region according to the model-estimated rate of each indicator and computed the correlation among relative ranks of each region over the ten-year study period. Results: 215,488 patients met eligibility criteria. Within this broader and more recent sample we confirmed previous observations of steadily and significantly increasing use of chemotherapy within 2 weeks of death, emergency room visits, and intensive care unit admissions in the last month of life, and, among those admitted to hospice, an increasing proportion of late admissions within 3 days of death. There was significant regional variation in all measures, but the relative rankings of health care service areas from one year to the next were stable, with correlations of ranks ranging from .91–.98 from 1991–1992, and .66–.84 over the 5-year span from 1991–1995. Because of significant regional variation in trends, we found only moderate correlations ranging from .40–.61 over the entire decade. Conclusions: Cancer treatment near the end of life continued to become increasingly aggressive over the 1990s, however, there was significant regional variation in trends. The stability of regional practice patterns supports the reliability of these measures for quality surveillance purposes.

[Table: see text]

No significant financial relationships to disclose.

DPC 681 and DPC 684: potent, selective inhibitors of human immunodeficiency virus protease active against clinically relevant mutant variants

Human immunodeficiency virus (HIV) protease inhibitors (PIs) are important components of many highly active antiretroviral therapy regimens. However, development of phenotypic and/or genotypic resistance can occur, including cross-resistance to other PIs. Development of resistance takes place because trough levels of free drug are inadequate to suppress preexisting resistant mutant variants and/or to inhibit de novo-generated resistant mutant variants. There is thus a need for new PIs, which are more potent against mutant variants of HIV and show higher levels of free drug at the trough. We have optimized a series of substituted sulfonamides and evaluated the inhibitors against laboratory strains and clinical isolates of HIV type 1 (HIV-1), including viruses with mutations in the protease gene. In addition, serum protein binding was determined to estimate total drug requirements for 90% suppression of virus replication (plasma IC(90)). Two compounds resulting from our studies, designated DPC 681 and DPC 684, are potent and selective inhibitors of HIV protease with IC(90)s for wild-type HIV-1 of 4 to 40 nM. DPC 681 and DPC 684 showed no loss in potency toward recombinant mutant HIVs with the D30N mutation and a fivefold or smaller loss in potency toward mutant variants with three to five amino acid substitutions. A panel of chimeric viruses constructed from clinical samples from patients who failed PI-containing regimens and containing 5 to 11 mutations, including positions 10, 32, 46, 47, 50, 54, 63, 71, 82, 84, and 90 had mean IC(50) values of <20 nM for DPC 681 and DPC 681, respectively. In contrast, marketed PIs had mean IC(50) values ranging from 200 nM (amprenavir) to >900 nM (nelfinavir).

4,1-Benzoxazepinone analogues of efavirenz (Sustiva) as HIV-1 reverse transcriptase inhibitors

A series of 4,1-benzoxazepinone analogues of efavirenz (Sustiva) as potent NNRTIs has been discovered. The cis-3-alkylbenzoxazepinones are more potent then the trans isomers and can be synthesized preferentially by a novel stereoselective cyclization. The best compounds are potent orally bioavailable inhibitors of both wild-type HIV-1 and its clinically relevant K103N mutant virus, but are highly protein-bound in human plasma.

Genotypic correlates of phenotypic resistance to efavirenz in virus isolates from patients failing nonnucleoside reverse transcriptase inhibitor therapy

Efavirenz (also known as DMP 266 or SUSTIVA) is a potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) activity and of HIV-1 replication in vitro and in vivo. Most patients on efavirenz-containing regimens have sustained antiviral responses; however, rebounds in plasma viral load have been observed in some patients in association with the emergence of mutant strains of HIV-1. Virus isolates from the peripheral blood mononuclear cells (PBMCs) of patients with such treatment failures, as well as recombinant viruses incorporating viral sequences derived from patient plasma, show reduced in vitro susceptibility to efavirenz in association with mutations in the RT gene encoding K103N, Y188L, or G190S/E substitutions. Patterns of RT gene mutations and in vitro susceptibility were similar in plasma virus and in viruses isolated from PBMCs. Variant strains of HIV-1 constructed by site-directed mutagenesis confirmed the role of K103N, G190S, and Y188L substitutions in reduced susceptibility to efavirenz. Further, certain secondary mutations (V106I, V108I, Y181C, Y188H, P225H, and F227L) conferred little resistance to efavirenz as single mutations but enhanced the level of resistance of viruses carrying these mutations in combination with K103N or Y188L. Viruses with K103N or Y188L mutations, regardless of the initial selecting nonnucleoside RT inhibitor (NNRTI), exhibited cross-resistance to all of the presently available NNRTIs (efavirenz, nevirapine, and delavirdine). Some virus isolates from nevirapine or delavirdine treatment failures that lacked K103N or Y188L mutations remained susceptible to efavirenz in vitro, although the clinical significance of this finding is presently unclear.

Synthesis and Evaluation of Efavirenz (SustivaTM) Analogues as HIV-1 Reverse Transcriptase Inhibitors: Replacement of the Cyclopropylacetylene Side Chain

Two series of efavirenz analogues have been developed: one in which the cyclopropane ring has been replaced by small heterocycles and another in which the entire acetylenic side chain has been replaced by alkyloxy groups. Several members of both series show equivalent potency to efavirenz against both wild-type virus and the key K103N mutant.

Inhibition of clinically relevant mutant variants of HIV-1 by quinazolinone non-nucleoside reverse transcriptase inhibitors

A series of 4-alkenyl and 4-alkynyl-3, 4-dihydro-4-(trifluoromethyl)-2-(1H)-quinazolinones were found to be potent non-nucleoside reverse transcriptase inhibitors (NNRTIs) of human immunodeficiency virus type-1 (HIV-1). The 4-alkenyl-3, 4-dihydro-4-(trifluoromethyl)-2-(1H)-quinazolinones DPC 082 and DPC 083 and the 4-alkynyl-3, 4-dihydro-4-(trifluoromethyl)-2-(1H)-quinazolinones DPC 961 and DPC 963 were found to exhibit low nanomolar potency toward wild-type RF virus (IC(90) = 2.0, 2.1, 2.0, and 1.3 nM, respectively) and various single and many multiple amino acid substituted HIV-1 mutant viruses. The increased potency is combined with favorable plasma serum protein binding as demonstrated by improvements in the percent free drug in human plasma when compared to efavirenz: 3.0%, 2.0%, 1.5%, 2. 8%, and 0.2-0.5% for DPC 082, DPC 083, DPC 961, DPC 963, and efavirenz, respectively.

Expanded-spectrum nonnucleoside reverse transcriptase inhibitors inhibit clinically relevant mutant variants of human immunodeficiency virus type 1

A research program targeted toward the identification of expanded-spectrum nonnucleoside reverse transcriptase inhibitors which possess increased potency toward K103N-containing mutant human immunodeficiency virus (HIV) and which maintain pharmacokinetics consistent with once-a-day dosing has resulted in the identification of the 4-cyclopropylalkynyl-4-trifluoromethyl-3, 4-dihydro-2(1H)quinazolinones DPC 961 and DPC 963 and the 4-cyclopropylalkenyl-4-trifluoromethyl-3, 4-dihydro-2(1H)quinazolinones DPC 082 and DPC 083 for clinical development. DPC 961, DPC 963, DPC 082, and DPC 083 all exhibit low-nanomolar potency toward wild-type virus, K103N and L100I single-mutation variants, and many multiply amino acid-substituted HIV type 1 mutants. This high degree of potency is combined with a high degree of oral bioavailability, as demonstrated in rhesus monkeys and chimpanzees, and with plasma serum protein binding that can result in significant free levels of drug.

Angiotensin-converting enzyme insertion/deletion polymorphism in angina pectoris with normal coronary arteriograms

We investigated the relation between angiotensin-converting enzyme gene insertion/deletion polymorphism and syndrome X (angina with normal coronary arteriogram). The results of our study suggest that this polymorphism does not play a major role in the pathogenesis of microvascular angina.

The importance of the lumpectomy surgical margin status in long-term results of breast conservation

BACKGROUND

The impact of the surgical margin status on long-term local control rates for breast cancer in women treated with lumpectomy and radiation therapy is unclear.

METHODS

The records of 289 women with 303 invasive breast cancers who were treated with lumpectomy and radiation therapy from 1972 to 1992 were reviewed. The surgical margin was classified as positive (transecting the inked margin), close (less than or equal to 2 mm from the margin), negative, or indeterminate, based on the initial biopsy findings and reexcision specimens, as appropriate. Various clinical and pathologic factors were analyzed as potential prognostic factors for local recurrence in addition to the margin status, including T classification, N classification, age, histologic features, and use of adjuvant therapy. The mean follow-up was 6.25 years.

RESULTS

The actuarial probability of freedom from local recurrence for the entire group of patients at 5 and 10 years was 94% and 87%, respectively. The actuarial probability of local control at 10 years was 98% for those patients with negative surgical margins versus 82% for all others (P = 0.007). The local control rate at 10 years was 97% for patients who underwent reexcision and 84% for those who did not. Reexcision appears to convey a local control benefit for those patients with close, indeterminate, or positive initial margins, when negative final margins are attained (P = 0.0001). Final margin status was the most significant determinant of local recurrence rates in univariate analysis. By multivariate analysis, the final margin status and use of adjuvant chemotherapy were significant prognostic factors.

CONCLUSIONS

The attainment of negative surgical margins, initially or at the time of reexcision, is the most significant predictor of local control after breast-conserving treatment with lumpectomy and radiation therapy.

Angiotensin-converting enzyme genotype is not associated with endothelial dysfunction in subjects without other coronary risk factors

The DD genotype is a polymorphism of the angiotensin-converting enzyme (ACE) gene, and is associated with a significantly increased risk of myocardial infarction. As endothelial dysfunction is an important event in both early atherogenesis and late atherosclerosis, we hypothesised that the adverse effect associated with the ACE/DD genotype might be mediated via endothelial damage. Using high resolution ultrasound, we studied the brachial arteries of 184 subjects aged 15-73 (mean 38 +/- 14) years, who were all normotensive, non-diabetic lifelong non-smokers. Arterial diameter was measured at rest, during reactive hyperaemia (with flow increase causing endothelium-dependent dilation) and after sublingual glyceryl trinitrate (GTN, an endothelium-independent vasodilator). The ACE genotype was determined in each case by DNA amplification; 49/184(27%) had DD, 89 (48%) had ID and 46 (25%) had II genotype. Flow-mediated dilation (FMD) was 8.5% +/- 3.9% in the DD, 7.8% +/- 4.1% in the ID and 7.8% +/- 4.1% in the II subjects (P = NS). GTN-induced dilation was also similar in the 3 groups. On multivariate analysis, endothelium-dependent dilation was inversely related to age (r = -0.33, P < 0.001), vessel size (r = -0.41, P < 0.001) but not ACE genotype (r = 0.002, P = 0.97). The ACE genotype is unrelated to endothelium-dependent dilation in the systemic arteries of clinically well adults. This suggests that the risk associated with this polymorphism may be mediated by other mechanisms.

Membrane and protein interactions of a soluble form of the Semliki Forest virus fusion protein

Semliki Forest virus is an enveloped alphavirus that infects cells by a membrane fusion reaction triggered by the low pH present in endocytic vacuoles. Fusion is mediated by the E1 spike protein subunit. During fusion, several conformational changes occur in E1 and E2, the two transmembrane subunits of the spike protein. These changes include dissociation of the E1-E2 dimer, alteration of the trypsin sensitivity and monoclonal antibody binding patterns of E1, and formation of a sodium dodecyl sulfate (SDS)-resistant E1 homotrimer. A critical characteristic of Semliki Forest virus fusion is also its dependence on the presence of both cholesterol and sphingomyelin in the target membrane. We have here examined the conformational changes induced by low pH treatment of E1*, the water-soluble, proteolytically truncated ectodomain of the E1 subunit. Following low pH treatment, E1* was shown to bind efficiently to artificial liposomes. Similar to virus fusion, optimal E1*-liposome binding required low pH, cholesterol, and sphingomyelin. The E1 ectodomain, although monomeric in its neutral pH form, assembled into an SDS-resistant oligomer following treatment at low pH. This low pH-induced oligomerization required target membranes containing both cholesterol and sphingomyelin. Our results demonstrate that the E1 ectodomain responds to low pH similarly to the full-length E1 subunit. The ectodomain facilitates the characterization of conformational changes and membrane binding in the absence of virus fusion or other virus components.

A positive feedback loop coordinates growth and patterning in the vertebrate limb

Limb development depends on signals from the apical ectodermal ridge and underlying mesenchyme. Fibroblast growth factor (FGF) can replace the ridge and, because Fgf4 RNA is localized to the mouse posterior ridge, we proposed that FGF4 is the endogenous ridge signal. Ridge signals control limb outgrowth and maintain the zone of polarizing activity (ZPA) at the limb posterior margin, which is important in limb pattering: a ZPA graft to limb anterior mesenchyme causes cell respecification and mirror-image duplications. Sonic hedgehog (SHH) has polarizing activity, and Shh RNA co-localizes with ZPA activity, suggesting SHH is the endogenous polarizing signal. We have investigated the molecular regulation of Fgf4 and Shh expression. We report here that Fgf4 expression in the ridge can be regulated by Shh-expressing cells. Moreover, Shh expression in mesenchyme can be activated by FGF4 in combination with retinoic acid. Once induced, Shh expression can be maintained by FGF4 alone, thus establishing a positive feedback loop between ZPA and ridge.

The kallikrein-kinin and renin-angiotensin systems in nephrotic syndrome

We previously found that virtually all patients with nephrotic syndrome (NS) excrete supranormal amounts of urinary kallikrein; it is known that activity of the renin-angiotensin system (RAS) is increased in some such patients. We therefore studied the relationship between urinary kallikrein excretion (UKa) and plasma renin activity (PRA) in 16 patients with NS. Compared with healthy controls, PRA was normal in 8 subjects and elevated in 8; UKa was elevated in the high-renin group (40.4 +/- 5.2 nkat/24 h, normals 12.0 +/- 1.1). UKa was also elevated in the normal renin group (25.7 +/- 2.4 nkat/24 h) but to a significantly lesser degree. Significant activity in plasma against a specific substrate of glandular and renal kallikreins was observed in 8 of 10 patients with NS. Such activity was not found in plasma of 17 patients with glomerulonephritis without NS, or in 10 healthy controls. The results are in keeping with previous suggestions of a functional link between the renal kallikrein-kinin system (KKS) and the RAS, but indicate that the renal KKS is activated in NS, in some cases independently of the RAS. It is possible that renal kallikrein reaches the systemic circulation in some patients with NS.