Paradoxical inhibition of T-cell function in response to CTLA-4 blockade; heterogeneity within the human T-cell population

T-cell co-stimulation delivered by the molecules B7-1 or B7-2 through CD28 has a positive effect on T-cell activation, whereas engagement of cytotoxic T-lymphocyte antigen 4 (CTLA-4) by these molecules inhibits activation. In vivo administration to mice of blocking monoclonal antibodies or Fab fragments against CTLA-4 can augment antigen-specific T-cell responses and, thus, therapy with monoclonal antibody against CTLA-4 has potential applications for tumor therapy and enhancement of vaccine immunization. The effects of B7-1 and B7-2 co-stimulation through CD28 depend on the strength of the signal delivered through the T-cell receptor (TCR) and the activation state of T cells during activation. Thus, we sought to determine whether these factors similarly influence the effect of B7-mediated signals delivered through CTLA-4 during T-cell activation. Using freshly isolated human T cells and Fab fragments of a monoclonal antibody against CTLA-4, we demonstrate here that CTLA-4 blockade can enhance or inhibit the clonal expansion of different T cells that respond to the same antigen, depending on both the T-cell activation state and the strength of the T-cell receptor signal delivered during T-cell stimulation. Thus, for whole T-cell populations, blocking a negative signal may paradoxically inhibit immune responses. These results provide a theoretical framework for clinical trials in which co-stimulatory signals are manipulated in an attempt to modulate the immune response in human disease.

Traceable calibration of ultraviolet meters used with broadband, extended sources

A calibration system has been developed to provide increased accuracy in the measurement of the irradiance responsivity appropriate for UV meters used with broadband, extended sources of the type employed in phototherapy. The single wavelength responsivity of the test meter is obtained in the wavelength range 250-400 nm by intercomparison with a transfer standard meter in a narrow, monochromatic beam. Traceability to primary standard irradiance scales is provided via the National Measurement System with a best uncertainty of 7% (at 95% confidence). The effective responsivity of the test meter, when used with broadband extended sources, is calculated using the measured spectral and angular response of the meter and tabulated data on the spectral and spatial characteristics of the source radiance. The uncertainty in the effective responsivity, independent of the source variability, is estimated to be 10% (at 95% confidence). The advantages of this calibration system over existing approaches are discussed.

Changes in the levels of soluble adhesion molecules and coagulation factors in patients with deep vein thrombosis

Current biochemical markers of thrombosis, such as d-dimer, are of little value in demonstrating the presence of thrombus postoperatively, as their levels are elevated by surgery. Thrombosis involves adhesive interactions between the endothelium, platelets and leukocytes. The aim of the study was to determine which of a panel of haemostatic and adhesion factors are altered by the presence of thrombus, but not by surgery. These factors were measured in 20 patients with established spontaneous DVTs, 13 patients having hip replacement surgery and 28 control patients. Circulating levels of P-selectin, VCAM-1 and tissue factor were found to be increased when thrombus was present (p <0.018, p <0.0001, p <0.0028 respectively), but were not altered by surgery. The significance of these circulating factors in venous thrombosis remains to be established, but it is conceivable that they are the product of increased leukocyte trafficking and activity. Assay of VCAM-1, in particular, may be of use in the early detection of venous thrombi in postoperative patients.

Maternal infection, fetal inflammatory response, and brain damage in very low birth weight infants. Developmental Epidemiology Network Investigators

Echolucent images (EL) of cerebral white matter, seen on cranial ultrasonographic scans of very low birth weight newborns, predict motor and cognitive limitations. We tested the hypothesis that markers of maternal and feto-placental infection were associated with risks of both early (diagnosed at a median age of 7 d) and late (median age = 21 d) EL in a multi-center cohort of 1078 infants <1500 x g. Maternal infection was indicated by fever, leukocytosis, and receipt of antibiotic; fetoplacental inflammation was indicated by the presence of fetal vasculitis (i.e. of the placental chorionic plate or the umbilical cord). The effect of membrane inflammation was also assessed. All analyses were performed separately in infants born within 1 h of membrane rupture (n = 537), or after a longer interval (n = 541), to determine whether infection markers have different effects in infants who are unlikely to have experienced ascending amniotic sac infection as a consequence of membrane rupture. Placental membrane inflammation by itself was not associated with risk of EL at any time. The risks of both early and late EL were substantially increased in infants with fetal vasculitis, but the association with early EL was found only in infants born > or =1 after membrane rupture and who had membrane inflammation (adjusted OR not calculable), whereas the association of fetal vasculitis with late EL was seen only in infants born <1 h after membrane rupture (OR = 10.8; p = 0.05). Maternal receipt of antibiotic in the 24 h just before delivery was associated with late EL only if delivery occurred <1 h after membrane rupture (OR = 6.9; p = 0.01). Indicators of maternal infection and of a fetal inflammatory response are strongly and independently associated with EL, particularly late EL.

Complete sequence determination of the mouse and human CTLA4 gene loci: cross-species DNA sequence similarity beyond exon borders

CTLA4 (CD152), a receptor for the B7 costimulatory molecules (CD80 and CD86), is considered a fundamental regulator of T-cell activation. In this paper, we present the complete primary structure of the mouse and human CTLA4 gene loci. Sequence comparison between the mouse and the human CTLA4 gene loci revealed a high degree of sequence conservation both for homologous noncoding regions (65-78% identity) and for coding regions (72-98% identity), with an overall score of 71% over the entire length of the two genes. Of the CTLA4 genomic regions aligned, five simple repetitive elements were found in the mouse locus, whereas two simple repetitive sequences were localized on the human locus. RNA blot analysis of mouse and human primary tissues indicated that both CTLA4 and T-cell receptor transcripts were found in most organs with generally higher levels in lymphoid tissues. The conservation of CTLA4 gene patterning raises the possibility that constrained gene evolution of CTLA4 may be linked to conserved transcriptional control of this locus.

Cloning and characterization of the prostate-specific membrane antigen promoter

Prostate-specific membrane antigen (PSMA) is a protein that is expressed predominantly in normal prostate epithelial cells and in most adenocarcinomas of the prostate (Cap) and in virtually all Cap metastases. In this article we describe the cloning of a 2-kb human genomic DNA fragment containing the 5' upstream untranslated region of the PSMA gene and present evidence that it provides promoter activity. When the DNA fragment was cloned into transient expression vectors to examine promoter activity, the vectors were functional in promoting expression in several prostate and nonprostate cell lines in transient transfection assays. A 614-bp fragment derived from the 3' end of the 2-kb fragment may represent the minimal PSMA promoter as determined by deletion mutagenesis. The 2-kb fragment compared with the 614-bp fragment provided higher expression levels when using prostate-derived cell lines (DU 145 and LNCaP). The increased transcription using the 2-kb fragment was not as great in non-prostate cell lines. Little or no transcription over basal levels was seen with a 232-bp promoter fragment. When the concentration of dihydrotestosterone was depleted or supplemented in the growth medium, no significant effect was seen on PSMA-promoted transient expression in LNCaP cells, a prostate cell line. J. Cell. Biochem. 74:395-405, 1999. Published 1999 Wiley-Liss, Inc.

A Phase II study of paclitaxel and ifosfamide for patients with advanced refractory carcinoma of the urothelium

BACKGROUND

Cisplatin-based combination chemotherapy for patients with advanced transitional cell carcinoma (TCC) of the urothelium has limitations, and new therapies need to be evaluated.

METHODS

Ifosfamide 1.0 gm/m2 on Days 1-4 and paclitaxel 135 mg/m2 by 24-hour infusion on Day 4 were administered to 26 patients with locally unresectable or metastatic TCC. Cycles were repeated every 21 days for a maximum of 6 cycles; dose escalation was dependent on whether Grade 3 or 4 toxicities occurred.

RESULTS

There were 24 males and 2 females, with a median age of 66 years and a median Eastern Cooperative Oncology Group performance status of 0. The median number of cycles administered was 3. Twelve patients had Grade 3 or 4 hematologic toxicities, including 1 patient who died of a gastrointestinal hemorrhage while pancytopenic. There were no episodes of neutropenic fever. Two patients each had a complete response (CR) that lasted 5 and 28 months, respectively (response rate: 15%; 95% CI: 2-45%), among the 13 patients who had received prior chemotherapy. Of the 13 patients without prior chemotherapy, there were 3 with complete responses and 1 with a partial response ranging from 8 to 25+ months (RR: 30.7%; 95% CI: 9-61%).

CONCLUSIONS

The combination of ifosfamide and paclitaxel is well tolerated and can produce objective responses in patients who are chemonaïve or have had prior therapy. For previously untreated patients, the addition of ifosfamide does not appear to result in a better response rate than single agent paclitaxel; and for previously treated patients, the addition of paclitaxel does not appear to result in a better response rate than single agent ifosfamide.

Retrovirus targeting by tropism restriction to melanoma cells

Targeted vectors will be necessary for many gene therapy applications. To target retroviruses to melanomas, we fused a single-chain variable fragment antibody (scFv) directed against the surface glycoprotein high-molecular-weight melanoma-associated antigen (HMW-MAA) to the amphotropic murine leukemia virus envelope. A proline-rich hinge and matrix metalloprotease (MMP) cleavage site linked the two proteins. The modified viruses bound only to HMW-MAA-expressing cells, as inclusion of the proline-rich hinge prevented viral binding to the amphotropic viral receptor. Following attachment to HMW-MAA, MMP cleavage of the envelope at the melanoma cell surface removed the scFv and proline-rich hinge, allowing infection. Complexing of targeted retroviruses with 2, 3-dioleoyloxy-N-[2(spermine-carboxamido)ethyl]N, N-dimethyl-1-propanaminium trifluoroacetate-dioleoyl phosphatidylethanolamine liposomes greatly increased their efficiency without affecting their target cell specificity. In a cell mixture, 40% of HMW-MAA-positive cells but less than 0.01% of HMW-MAA-negative cells were infected. This approach can therefore produce efficient, targeted retroviruses suitable for in vivo gene delivery and should allow specific gene delivery to many human cell types by inclusion of different scFv and protease combinations.

Differences in semantic category priming in the left and right cerebral hemispheres under automatic and controlled processing conditions

The contribution of each cerebral hemisphere to the generation of semantic category meanings at automatic and strategic levels of processing was investigated in a priming experiment where prime and target words were independently projected to the left or right visual fields (LVF or RVF). Non-associated category exemplars were employed as related pairs in a lexical decision task and presented in two experimental conditions. The first condition was designed to elicit automatic processing, so related pairs comprised 20% of the positive set, stimulus pairs were temporally separated by a stimulus onset asynchrony (SOA) of 250 ms, and there was no allusion to the presence of related pairs in the instructions to subjects. The second condition, designed to invoke controlled processing, incorporated a relatedness proportion of 50%, stimulus pairs separated by an SOA of 750 ms, and instructions which informed subjects of the presence and use of category exemplar pairs in the stimulus set. In the first condition, a prime directed to either visual field facilitated responses to categorically related targets subsequently projected to the RVF, while in the second condition a prime directed to either visual field facilitated responses to related targets projected to the LVF. The facilitation effects obtained in both conditions appeared to reflect automatic processes, while strategic processes were invoked in the left, but not the right hemisphere in the second condition. The results suggest that both hemispheres have automatic access to semantic category meanings, although the timecourse of activation of semantic category meanings is slower in the right hemisphere than in the left.

Does the presence of a tracheoesophageal fistula predict the outcome of laryngeal cleft repair?

OBJECTIVE

To determine if the presence of a tracheo-esophageal fistula (TEF) alters outcome following laryngeal cleft repair.

DESIGN

A retrospective review of patients diagnosed and treated for laryngeal clefts, with a minimum follow-up period of 1 year.

SETTING

An academic tertiary care children's hospital.

PATIENTS

Twenty-five pediatric patients diagnosed and surgically treated for laryngeal cleft.

MAIN OUTCOME MEASURES

Each chart was reviewed to determine if patients with a laryngeal cleft had been diagnosed with TEF and had undergone a surgical TEF repair procedure. The success of the surgery was evaluated based on the resolution of symptoms and the endoscopic evaluation of the repair site.

RESULTS

Twenty-five patients were reviewed for study purposes. Fourteen had a history of TEF repair and 11, no history of TEF. All 25 patients underwent surgical repair of the laryngeal cleft. Twelve of the 14 patients with a history of TEF repair experienced a breakdown of the laryngeal cleft repair. Only 1 of the 11 patients with no history of TEF experienced such a breakdown. In 8 of 9 patients with a laryngotracheoesophageal type I cleft, surgical repair was not successful.

CONCLUSIONS

In our series, patients with laryngeal clefts who also had a history of TEF had a much higher incidence of breakdown of cleft repair compared with patients with no history of TEF. This finding is not conclusive and requires further investigation. The failure of cleft repair correlated with the severity of the cleft. The importance of these associations may lead to enhanced surgical planning and realistic preoperative family expectations.

Fibrous lesion of the distal femur associated with angular deformity

Unilateral femoral angulation is uncommon. We describe two children with unilateral progressive distal femoral varus and limb-length discrepancy. These deformities were associated with a fibrous lesion involving the medial aspect of the distal femoral metaphysis. Both patients were 15 to 16 months old. In both, the deformity was progressive, resulting in excisional biopsy and osteotomy. The gross and microscopic appearance of both lesions was similar, and the histology was dense fibrous connective tissue. The patients' femoral alignment was maintained at follow-up of a minimum of 16-36 months. The etiology of these lesions is unknown; they are associated with progressive deformity and appear to respond well to surgical intervention.

A model of in vivo human venous thrombosis that confirms changes in the release of specific soluble cell adhesion molecules in experimental venous thrombogenesis

PURPOSE

The mechanisms of venous thrombogenesis have been studied by using animal models and cells in culture. The results from these systems may not, however, be relevant to the human condition. The aim of this study was to develop a method by which thrombus could be safely produced in a human vein in vivo. The model that was developed was used as a means of studying the changes in soluble adhesion molecule expression in human venous thrombogenesis.

METHODS

An autologous thrombin extract was used to generate experimental thrombi in the disconnected portion of the long saphenous veins of 30 patients who were undergoing routine bilateral varicose vein surgery. The contralateral vein was perfused with thrombin extract diluent buffer to act as the control. The concentration of soluble P-, E- and L-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule-1 were measured by means of specific enzyme-linked immunosorbent assays in samples of blood taken from veins in which thrombus had formed and in contralateral control veins.

RESULTS

Thrombosis invariably formed when at least 100 IU of thrombin activity was administered. Thrombus formation was independent of the time that the thrombin extract was allowed to remain within the emptied vessel. Thrombosis never developed in control vessels that were similarly treated with the buffer used to dilute the thrombin extract. Experimental thrombi were composed mainly of red cells, with layers of fibrin next to platelet and leukocyte packages. These findings are similar to those observed in samples of established human venous thrombi. There were small but significantly higher levels of the adhesion molecules, soluble P-selectin, and vascular cell adhesion molecule-1 in blood taken from veins in which experimental thrombi had formed, compared with controls (P =.015 and.007, respectively; Wilcoxon signed rank test). Serum levels of soluble L-selectin, E-selectin, and ICAM-1 were not affected by thrombosis.

CONCLUSION

This model is safe and reproducible. It produces thrombi with a morphology similar to that described for established human deep venous thrombi. The model may be appropriate for the study of the early changes that occur during human venous thrombogenesis and may also be of value in testing the efficacy of novel antithrombotic agents.

JNK activation is not required for Fas-mediated apoptosis

Fas ligation in the presence of cycloheximide induced Jun N-terminal kinase 1 (JNK1) and JNK2 phosphorylation, caspase activation and cell death in the IL-3-dependent cell line BAF3. Fas-mediated apoptosis was prevented by expression of dominant negative FADD but not inhibited by IL-3. To investigate the role of JNK activation in this process, we examined cells over-expressing a JNK-specific phosphatase M3/6. M3/6 prevented Fas stimulation of JNK, but did not affect Fas-mediated caspase activation or cell death, demonstrating that JNK activation is not required for these processes.

Male genitourinary cancer sexuality questionnaire

In recent years the focus of cancer nursing care has expanded to include not only survival issues, but also quality of life. Sexuality is a significant aspect of quality of life. The purposes of this study were to describe patient-identified sexuality information needs, and the preferred method and setting for receiving this information. The results provide nurses with a baseline to structure teaching sessions to best meet the needs of this population. In recent years the focus of cancer nursing care has expanded to include not only survival issues, but also quality of life. Sexuality is a significant aspect of quality of life acknowledged by the American Nurses Association and the Oncology Nursing Society (1979) as a designated aspect of nursing care since 1979. Fonesca describes sexuality as the quality of being human (Hughes, 1996). As an expression of one's self physically, socially, and psychologically, sexuality involves more than sexual activity. It is communicated in ways that include bodily movements, interactions with others in everyday encounters, and expressions of the deepest feelings of love (Fonesca, 1970). Sexuality also includes one's intimate feelings of individuality and the need for emotional closeness with another person.

Effectiveness of clopidogrel and aspirin versus ticlopidine and aspirin in preventing stent thrombosis after coronary stent implantation

BACKGROUND

Ticlopidine has been shown to reduce the incidence of stent thrombosis compared with warfarin, but it may cause serious hematological side effects. Clopidogrel, a new thienopyridine derivative, may be a safe alternative to ticlopidine. The aim of this study was to compare the safety and efficacy of clopidogrel and aspirin with those of ticlopidine and aspirin in patients undergoing coronary stent implantation.

METHODS AND RESULTS

The population of this study consisted of 2 groups: patients who underwent coronary stenting and were treated with ticlopidine and aspirin (TA group, n=1406), and patients who underwent coronary stenting followed by treatment with clopidogrel and aspirin (CA group, n=283). At 1-month follow-up, there was no difference in stent thrombosis (1.5% versus 1.4%, P=1.0) or major adverse cardiac events (3.1% versus 2.4%, P=0. 85) between the TA and CA groups, respectively. The probability of any side effect (neutropenia, diarrhea, rash) was significantly higher in the TA group (10.6% versus 5.3%, P=0.006; relative risk, 0. 53; CI, 0.32 to 0.86).

CONCLUSIONS

These data suggest that clopidogrel may be an effective pharmacological regimen after coronary stent implantation. Furthermore, the simpler dosing regimen, the absence of neutropenia, and the lower frequency of other side effects make it a safe alternative to ticlopidine.

Acute hepatitis B infection in England and Wales: 1985-96

Confirmed acute hepatitis B infections are reported to the Public Health Laboratory Service Communicable Disease Surveillance Centre by laboratories in England and Wales. These reports have been used to monitor trends in the incidence of hepatitis B virus (HBV) infection over time, and between exposure categories and age groups. Between 1985 and 1996 a total of 9252 cases of acute HBV infection were reported; the number of reports fell from 1761 in 1985 to 581 in 1996. Most infections were reported in adults aged 15-44 years [n = 7365 (80%)], and infections were more commonly reported in males [n = 6490 (70%)] than females [n = 2658 (29%)]. The probable means of acquisition was known for just over half of all adult cases [4827/8956 (54%)]. Injecting drug use was the most common exposure [n = 1901 (21%)], followed by sex between men and women [n = 1140 (13%)] and sex between men [n = 1025 (11%)]. The number of infections in injecting drug users fell in the late 1980s, but increased again from 1991 onwards. In children aged under 15 years, infections acquired by mother to baby transmission accounted for 35/170 (21%) of the total. Surveillance indicates that the incidence of acute hepatitis B infection fell in the late 1980s, probably reflecting changed behaviour in injecting drug users. An increase in the number of infections in injecting drug users since 1993 may indicate ongoing transmission that has not been contained by the introduction of needle exchange schemes or by selective vaccination.

Seasonal and annual foraging movements of little penguins from Phillip Island, Victoria

Little penguins, Eudyptula minor, from a breeding colony on Phillip Island, Victoria were radio-tracked at sea during incubation, chick-rearing and non-breeding periods from 1991 to 1993. Their locations, which we have assumed to reflect foraging movements, varied according to season and breeding activities, and there were marked differences from year to year. Duration and distance of trips ranged from single day-trips a few kilometres from Phillip Island, typically during the breeding season, to longer trips outside the breeding season up to 500 km away lasting more than a month, but 95% of all birds located were within 20 km of the coast. In the breeding season foraging trips averaged 4.4 days during incubation compared with 2.1 days when there were chicks in the nest; in the non-breeding period foraging trips took 5.2 days on average. The duration of trips for adults feeding chicks increased with the age of the chicks. Birds from nests on the north and south sides of Phillip Island differed in their use of areas close to the island, but showed a similar distribution on more distant trips. The location of foraging trips is discussed in relation to information on the abundance of prey species of fish within the foraging range of the birds.

Assessment of regional wall motion abnormalities with real-time 3-dimensional echocardiography

Accurate characterization of regional wall motion abnormalities requires a thorough evaluation of the entire left ventricle (LV). Although 2-dimensional echocardiography is frequently used for this purpose, the inability of tomographic techniques to record the complete endocardial surface is a limitation. Three-dimensional echocardiography, with real-time volumetric imaging, has the potential to overcome this limitation by capturing the entire volume of the LV and displaying it in a cineloop mode. The purpose of this study was to assess the feasibility of using real-time 3-dimensional (RT3D) echocardiography to detect regional wall motion abnormalities in patients with abnormal LV function and to develop a scheme for the systematic evaluation of wall motion by using the 3-dimensional data set. Twenty-six patients with high-quality 2-dimensional echo images and at least 1 regional wall motion abnormality were examined with RT3D echocardiography. For 2-dimensional echocardiography, wall motion was analyzed with a 16-segment model and graded on a 4-point scale from normal (1) to dyskinetic (4), from which a wall motion score index was calculated. Individual segments were then grouped into regions (anterior, inferoposterior, lateral, and apical) and the number of regional wall motion abnormalities was determined. The RT3D echocardiogram was recorded as a volumetric, pyramid-shaped data set that contained the entire LV. Digital images, consisting of a single cardiac cycle cineloop, were analyzed off-line with a computerized display of the apical projection. Two intersecting orthogonal apical projections were simultaneously displayed in cineloop mode, each independently tilted to optimize orientation and endocardial definition. The 2 planes were then slowly rotated about the major axis to visualize the entire LV endocardium. Wall motion was then graded in 6 equally spaced views, separated by 30 degrees, yielding 36 segments per patient. A higher percentage of segments were visualized with 2-dimensional versus RT3D echocardiography (97% vs 83%, respectively, P <.001). With the use of the 2-dimensional echocardiographic results as the standard, RT3D echocardiography detected 55 (96%) of 57 regional wall motion abnormalities. Analysis of the RT3D echocardiograms resulted in 3 false-negative and 5 false-positive findings. The total number of regional wall motion abnormalities was correctly classified by RT3D echocardiography in 19 (73%) of 26 patients. RT3D echocardiography detected 11 of 13 anterior, 19 of 20 inferoposterior, 9 of 9 lateral, and 15 of 15 apical wall motion abnormalities. An excellent correlation was found between the 2 techniques for assessment of the regional wall motion score index (r = 0.89, P <.001). This initial clinical study demonstrates the feasibility and potential advantages of RT3D echocardiography for the assessment of regional LV function. Compared with 2-dimensional echocardiography, this new method permits recording of the entire LV in a single beat, allowing the extent and location of the regional wall motion abnormalities to be determined.