Targeting properties of an anti-CD16/anti-CD30 bispecific antibody in an in vivo system

Bispecific antibodies are currently being used in clinical trials in increasing numbers in the areas of breast cancer, prostate cancer, non-Hodgkin's lymphoma and Hodgkin's lymphoma. We have previously performed two clinical trials in patients with Hodgkin's disease with an anti-CD30/anti-CD16 bispecific antibody and demonstrated a 30% response rate in a cohort of patients otherwise resistant to standard therapeutic modalities. However, no surrogate marker could be defined in these trials indicative of optimal antibody dosing/scheduling or predictive for favorable response. In order to evaluate accurately the potential biodistribution properties of bispecific antibody in patients, we have performed a detailed analysis of the binding properties and animal model in vivo characteristics of these constructs. For this purpose, the parental antibodies (anti-CD30 and anti-CD16) and the bispecific antibody (anti-CD30/anti-CD16) were radiolabeled with either 125I or 111In. Antibody integrity and binding properties after labeling were confirmed by Scatchard plot and Lindmo analysis. 111In-labeled antibodies revealed superior targeting properties in a standard SCID mouse tumor model. Both the bivalent parental anti-CD30 monoclonal antibody and the monovalent anti-CD30/anti-CD16 bispecific antibody showed excellent uptake in CD30+ tumors which did not differ significantly between the two (maximum uptake 16.5%+/-4.2% vs. 18.4%+/-3.8% injected dose/gram tissue). The equivalent targeting properties of the bispecific antibody compared with the parental anti-CD30 antibody encourages the further clinical development of this bispecific antibody, and might help to explain the clinical responses seen with this antibody so far in patients suffering from Hodgkin's disease.

Regional cardiac expression and concentration of natriuretic peptides in patients with severe chronic heart failure

The purpose of this study was to examine the regional cardiac mRNA expression and concentration of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in relation to the circulating peptide concentrations in patients with chronic heart failure (CHF). The myocardial mRNA levels and peptide concentrations of BNP and ANP were analysed in seven different regions of the heart from patients undergoing cardiac transplantation. Autopsy samples from individuals without known cardiovascular disease were used as controls. The plasma levels of natriuretic peptides and their N-terminal propeptides, Nt-proBNP and Nt-proANP, were measured in the CHF patients and healthy volunteers. In the autopsy specimens, the atrial regions appeared to contain the highest peptide levels for BNP as well as ANP, the atrioventricular ratio being 12-262 and 72-637-fold, respectively. In the CHF patients there was a relative shift towards the ventricle for BNP, reducing the atrioventricular ratio to 6-16-fold. The circulating concentrations of BNP/Nt-proBNP in the CHF patients correlated closely to the BNP mRNA expression in most myocardial regions including the left ventricle (r = 0.72, P < 0.001). For circulating concentrations of ANP/Nt-proANP, such correlation were limited to the left atrium free wall (r = .66, P < 0.002). Thus, of the two natriuretic peptides, BNP/Nt-proBNP may be a better reflector of left ventricular overload.

HIRA, the human homologue of yeast Hir1p and Hir2p, is a novel cyclin-cdk2 substrate whose expression blocks S-phase progression

Substrates of cyclin-cdk2 kinases contain two distinct primary sequence motifs: a cyclin-binding RXL motif and one or more phosphoacceptor sites (consensus S/TPXK/R or S/TP). To identify novel cyclin-cdk2 substrates, we searched the database for proteins containing both of these motifs. One such protein is human HIRA, the homologue of two cell cycle-regulated repressors of histone gene expression in Saccharomyces cerevisiae, Hir1p and Hir2p. Here we demonstrate that human HIRA is an in vivo substrate of a cyclin-cdk2 kinase. First, HIRA bound to and was phosphorylated by cyclin A- and E-cdk2 in vitro in an RXL-dependent manner. Second, HIRA was phosphorylated in vivo on two consensus cyclin-cdk2 phosphoacceptor sites and at least one of these, threonine 555, was phosphorylated by cyclin A-cdk2 in vitro. Third, phosphorylation of HIRA in vivo was blocked by cyclin-cdk2 inhibitor p21(cip1). Fourth, HIRA became phosphorylated on threonine 555 in S phase when cyclin-cdk2 kinases are active. Fifth, HIRA was localized preferentially to the nucleus, where active cyclin A- and E-cdk2 are located. Finally, ectopic expression of HIRA in cells caused arrest in S phase and this is consistent with the notion that it is a cyclin-cdk2 substrate that has a role in control of the cell cycle.

Radioimmunoassay for N-terminal probrain natriuretic peptide in human plasma

Measurement of plasma levels of natriuretic peptides has been used to assess left ventricular dysfunction and prognosis. Recently levels of the N-terminal peptide fragment of the precursor of brain natriuretic peptide have been reported to be present in peripheral plasma and to be increased in chronic heart failure patients. Our aim in this study was to develop a radioimmunoassay for N-terminal proBNP, to compare its plasma concentrations in control subjects and in patients with end-stage heart failure and to define its relation to brain natriuretic peptide (BNP). A polyclonal antibody was raised in rabbits against human N-terminal proBNP fragment (amino acid 1-21). The plasma N-terminal proBNP concentrations were assayed directly without extraction. No detectable cross-reactivity existed with other natriuretic peptides: BNP, ANP or N-terminal proANP. The assay had a detection limit (2 SD from zero) of 9.7 pmol/L. Plasma N-terminal proBNP was 29 (13-75) (median (range)) pmol/L in the control group. There were no gender difference, male: 28 (13-61) vs. female 33 (13-75) pmol/L, p= NS, but there was a positive correlation to age (r=0.52, p<0.0001). In patients with end-stage heart failure the median N-terminal proBNP levels were increased significantly 616 (114-2781) pmol/L (p<0.001) and in pooled data N-terminal proBNP showed a close correlation to BNP (r=0.96, p<0.0001). Size exclusion of plasma extracts indicated that proBNP (1-108) may circulate both as intact prohormone and as split products, N-terminal proBNP (1-76) and BNP (77-108). Our results support the concept that N-terminal proBNP measurement could be a valuable tool in the biochemical indication of increased cardiac wall stress.

Plasma levels of natriuretic peptides and hemodynamic assessment of patent ductus arteriosus in preterm infants

The main purpose of this study was to investigate whether circulating natriuretic peptides in premature infants reflect the hemodynamic significance of a patent ductus arteriosus (PDA). The study comprises 120 examinations in 55 premature infants with a mean gestational age of 27.2 wk and a mean birthweight of 933 g. Based on clinical and echocardiographic findings, the hemodynamic influence of ductal shunting was classified as small, moderate or large. Blood samples for N-terminal proatrial natriuretic peptide (Nt-proANP) and brain natriuretic peptide (BNP) were analysed after completion of the clinical part of the study. Linear regression indicated a very strong association between Nt-proANP and BNP (adjusted R = 0.89). The mean levels of Nt-proANP and BNP increased with the size of the shunt through a PDA, and peptide values followed hemodynamic alterations. The size of PDA accounted for 50% and 47% of the total variation in the plasma values of Nt-proANP and BNP, respectively. In detecting an echocardiographically significant PDA, the area under a ROC curve was 0.94 for Nt-proANP and 0.90 for BNP.

CONCLUSION

The magnitude of shunting through a PDA is the main determinant of plasma levels of natriuretic peptides in premature infants. Nt-proANP and BNP seem to have the same pattern of secretion. Our findings indicate that measurements of natriuretic peptides may provide clinically relevant information in the hemodynamic assessment of premature infants.

Rectourethral fistula and massive rectal bleeding from iodine-125 prostate brachytherapy: a case report

Iodine-125 brachytherapy is an effective well-tolerated treatment for localized prostate cancer. Gastrointestinal complications of brachytherapy (minor rectal bleeding or tenesmus) are uncommon. Rectal ulceration or rectourethral fistulas after prostate brachytherapy are rare. We present a case of massive refractory rectal bleeding and rectourethral fistula, a complication of prostate brachytherapy never before reported. As a result of the patient's life-threatening symptoms aggressive surgical therapy was necessary.

The site occupancy of Mg in the brownmillerite structure and its effect on hydration properties: an X-ray/neutron diffraction and EXAFS study

Samples of pure (Ca2FeAlO5) and lightly doped (Ca2Fe0.95Al0.95Mg0.05Si0.05O5) brownmillerite have been synthesized. Synchrotron X-ray and neutron diffraction data have been collected so that the structures can be refined using, simultaneously, both diffraction data sets and known compositional information; this overcomes the problem of under-determinacy resulting from multi-occupation of the tetrahedrally and octahedrally coordinated sites in the structure. For the pure form, a 2.7:1 iron/aluminium preference for octahedral/tetrahedral (respectively) occupation is obtained. This trend is reflected also in the doped brownmillerite, though, because of the low level of Mg doping, the occupancy of Mg is only resolved through the additional use of Mg EXAFS (extended X-ray absorption fine structure) data, which shows that Mg displays a distinct octahedral site preference rather than a disordered occupation between the octahedral/tetrahedral sites. The consequences of Mg doping are then examined using time-resolved multi-angle energy-dispersive powder X-ray diffraction studies of the mineral undergoing hydration; this shows that the pure form is more active than the doped form.

Early neurohormonal effects of trandolapril in patients with left ventricular dysfunction and a recent acute myocardial infarction: a double-blind, randomized, placebo-controlled multicentre study

Angiotensin-converting enzyme inhibitors improve long-term survival in patients with left ventricular dysfunction after a myocardial infarction, but their mechanism of action is not entirely clear. The neurohormonal effects may be important in this respect, as well as an early hemodynamic unloading induced by these drugs. The primary objective was to assess the effect of trandolapril on plasma levels of atrial natriuretic peptide. A secondary objective was to assess the effects of trandolapril on selected neurohormones, vasoactive peptides and enzymes, which may be important in the development of left ventricular remodeling and heart failure following an acute myocardial infarction. A total of 119 patients with an acute myocardial infarction and a wall motion index < or =1.2 (16-segment echocardiographic model) were randomized to double blind treatment with trandolapril or placebo within 3-7 days after the onset of infarction. Blind treatment was discontinued 21 days after the index infarction. Venous blood samples were collected at rest, before randomization and on the day after treatment was discontinued. At the end of the study, there were no differences in plasma levels of atrial natriuretic peptide between the two treatment groups. Angiotensin-converting enzyme activity was suppressed and plasma renin activity was higher in the trandolapril group. No differences in plasma levels of N-terminal pro-atrial natriuretic peptide, brain natriuretic peptide, aldosterone, noradrenaline, adrenaline, vasopressin, big endothelin-1 and neuropeptide Y were found between the two treatment groups. There were positive correlations between several markers of neurohormonal activation at baseline and variables expressing left ventricular dysfunction and clinical heart failure. Neurohormonal activation is related to left ventricular dysfunction. The effects of 2-3 weeks of angiotensin-converting enzyme inhibition on neurohormonal activation does not predict the already established beneficial long-term effects after myocardial infarction. Thus, early modulation of circulatory neurohormone levels may not be a major mechanism for the efficacy of angiotensin-converting enzyme inhibitors in these patients. Selected plasma hormone markers may still be used to identify patients who might get the greatest benefit from treatment.

Estuary-associated syndrome in North Carolina: an occupational prevalence study

Atlantic coast estuaries recently have experienced fish kills and fish with lesions attributed to Pfiesteria piscicida and related dinoflagellates. Human health effects have been reported from laboratory exposure and from a 1997 Maryland fish kill. North Carolina has recorded Pfiesteria-related fish kill events over the past decade, but human health effects from environmental exposure have not been systematically investigated or documented here. At the request of the state health agency, comprehensive examinations were conducted in a cross-sectional prevalence study of watermen working where Pfiesteria exposure may occur: waters where diseased or stressed fish were reported from June to September 1997, and where Pfiesteria had been identified in the past. Controls worked on unaffected waterways. The study was conducted 3 months after the last documented Pfiesteria-related fish kill. The goal was to document any persistent health effects from recent or remote contact with fish kills, fish with lesions, or affected waterways, using the 1997 U.S. Centers for Disease Control and Prevention case description for estuary-associated syndrome (EAS). Examinations included comprehensive medical, occupational, and environmental history, general medical, dermatologic, and neurologic examinations, vision testing, and neuropsychologic evaluations. Seventeen of 22 watermen working in affected waters and 11 of 21 in unaffected waters reported exposure to a fish kill or to fish with lesions. We found no pattern of abnormalities on medical, neurologic, neuropsychologic, or NES-2 evaluation. By history, one subject in each group met the EAS criteria, neither of whom had significant neuropsychological impairment when examined. Watermen from affected waterways had a significant reduction in visual contrast sensitivity (VCS) at the midspatial frequencies, but we did not identify a specific factor or exposure associated with this reduction. The cohorts did not differ in reported occupational exposure to solvents (qualitative) or to other neurotoxicants; however, exposure history was not sufficiently detailed to measure or control for solvent exposure. This small prevalence study in watermen, conducted 3 months after the last documented fish kill related to Pfiesteria, did not identify an increased risk of estuary-associated syndrome in those working on affected waterways. A significant difference between the estuary and ocean watermen was found on VCS, which could not be attributed to any specific factor or exposure. VCS may be affected by chemicals, drugs, alcohol, and several developmental and degenerative conditions; it has not been validated as being affected by known exposure to dinoflagellate secretions. VCS should be considered for inclusion in further studies, together with documentation or quantification of its potential confounders, to assess whether it has utility in relationship to dinoflagellate exposure.

Curing energy pains: the energy efficiency best practice programme

Energy efficiency provides hospitals with opportunities to save costs, help the environment and improve the internal environment for staff and patients. The Government has set the health sector an energy saving target of 20%, equivalent to cuts of 60 m Pounds by 2001 and 1.2 Mt carbon dioxide. These savings can be achieved and exceeded, cost-effectively, if good practise is adopted throughout the sector. Assistance in meeting the Government's energy target and meeting good practice benchmarks is available from the Energy Efficiency Best Practise programme through BRECSU.

2000 Wolfe Award. Sumatriptan for the range of headaches in migraine sufferers: results of the Spectrum Study

BACKGROUND

Migraineurs experience a spectrum of headaches: migraine, migrainous, and episodic tension-type as defined by the International Headache Society (IHS).

OBJECTIVE

To evaluate the effectiveness of sumatriptan, 50-mg tablets, in treating the spectrum of headaches in IHS-diagnosed migraineurs.

DESIGN/METHODS

Migraineurs with severe disability (Headache Impact Questionnaire score 250 or greater) were enrolled in a randomized, double-blind, placebo-controlled, crossover study. Patients treated up to 10 headaches with sumatriptan, 50 mg, or placebo (4:1). Headache features, recorded prior to treatment, were used to classify each headache using IHS criteria. Headache response (moderate or severe pain reduced to mild or no pain) and pain-free response were recorded at 2 and 4 hours postdose (primary endpoint). Because patients treated multiple attacks, statistical methods controlling for within-subject correlation were used.

RESULTS

Two hundred forty-nine migraineurs treated 1576 moderate or severe headaches: migraine (n = 1110), migrainous (n = 103), and tension-type (n = 363). Sumatriptan was superior to placebo for headache response 4 hours postdose (primary endpoint) across all headache types (migraine, 66% versus 48%; P<.001; migrainous, 71% versus 39%; P<.01; tension-type, 78% versus 50%, P<.001). Sumatriptan was also superior to placebo for pain-free response 4 hours postdose for migraine (41% versus 24%, P<.001) and tension-type headaches (56% versus 36%, P =.001). Sumatriptan provided superior pain-free response 2 hours postdose for migraine (18% versus 7%, P<.0001) and tension-type headache (28% versus 14%, P =.0005) compared with placebo.

CONCLUSION

Sumatriptan, 50-mg tablets, are effective for the full spectrum of headaches experienced by patients with disabling migraine due to a sumatriptan-responsive mechanism.

Curing energy pains: the energy efficiency best practice programme

Energy efficiency provides hospitals with opportunities to save costs, help the environment and improve the internal environment for staff and patients. The Government has set the health sector an energy saving target of 20%, equivalent to cuts of 60 m Pounds by 2001 and 1.2 Mt carbon dioxide. These savings can be achieved and exceeded, cost-effectively, if good practise is adopted throughout the sector. Assistance in meeting the Government's energy target and meeting good practice benchmarks is available from the Energy Efficiency Best Practise programme through BRECSU.

Hereditary non-polyposis colorectal cancer: an updated review

INTRODUCTION

Colorectal cancer is the commonest cause of death due to malignancy in non-smokers in the western countries. The two main hereditary types of colorectal cancer are familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC), constituting approximately 10% of all cases of colorectal cancer. The main aim of this review is to reappraise the current advances in the genetics and diagnosis of HNPCC.

METHODS

A Medline search was carried out to identify papers published from 1970 to 1999 on HNPCC. Embase and Cochrane databases were also searched. Reference lists of retrieved articles were carefully searched for additional articles.

RESULTS AND CONCLUSIONS

Recent technological advances in the genetics of HNPCC have refined the criteria for diagnosis and management of HNPCC, however current policies regarding the testing of pedigrees are not clearly established. We believe that with the rapid development in this area definitive clinical guidelines will need to be available in future for the management of HNPCC.

Treatment of mild headache in disabled migraine sufferers: results of the Spectrum Study

OBJECTIVE

To evaluate the effectiveness of sumatriptan, 50-mg tablets, versus placebo for early intervention while head pain was mild in patients with disabling migraine.

METHODS

A post hoc analysis was performed in a subgroup of patients from a large, randomized, placebo-controlled study of patients with disabling headache who treated while pain was mild. Pain-free response 2 and 4 hours postdose, headache recurrence, and safety were examined. Significance tests were performed only for the first-treated attacks.

RESULTS

Twenty-six patients with disabling headache treated 46 mild and 166 moderate or severe headaches. For the first-treated headaches while pain was mild, pain-free rates were significantly higher for sumatriptan than placebo 4 hours postdose (78% versus 0%, P =.02), but not 2 hours postdose (52% versus 0%, P =.22). Across all headaches treated while pain was mild, pain-free responses were higher for sumatriptan than placebo 4 hours (85% versus 17%) and 2 hours (50% versus 0%) postdose compared with placebo. When the same patients treated headaches while pain was moderate or severe, pain-free rates were lower than that reported for treatment during mild pain. There was a trend toward lower headache recurrence in headaches treated while pain was mild compared with moderate or severe pain (13% versus 18%). No drug-related adverse events were reported in the headaches treated while pain was mild.

CONCLUSIONS

Patients with disabling migraine may benefit from early intervention with sumatriptan, 50 mg, while pain is mild.

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

N-terminal proatrial natriuretic peptide and prognosis in patients with heart failure and preserved systolic function

BACKGROUND

Congestive heart failure and preserved left ventricular systolic function is a common clinical condition. Although the prognosis in this type of heart failure is better in comparison to systolic dysfunction, prognostic markers to evaluate long-term outcome are lacking. The atrial peptide, N-terminal proatrial natriuretic peptide (proANP), has been shown to predict survival in patients with systolic dysfunction. We intended to evaluate the predictive capability of N-terminal proANP in patients with preserved systolic function (ejection fraction [EF] > or = 0.40).

METHODS AND RESULTS

A clinical and echocardiographic examination was performed in 149 patients with idiopathic heart failure from a population-based cohort, and 84 patients were identified to have preserved systolic function, with an EF of 0.40 or greater. The patients were followed up during 7 years with regard to symptoms, treatment, hospitalization, and survival. The patients with normal EFs had greater plasma concentrations of N-terminal proANP compared with a control group, and N-terminal proANP level was an independent predictor of mortality (risk ratio, 2.44; 95% confidence interval, 1.28 to 4.67; P = .007). In addition, a high concentration of N-terminal proANP predicted an increased rate of hospitalization (50% for a level > 1,200 pmol/L versus 19% for a level < or = 1,200 pmol/L; P = .046) and a greater future dosage of diuretic (127+/-102 vs 51+/-39 mg; P = .007).

CONCLUSION

N-terminal proANP level was an independent marker of increased mortality and morbidity in patients with preserved systolic function, whereas EF was not usable in this regard. It is suggested that this peptide could be used to identify clinically relevant left ventricular dysfunction in patients with EFs within the normal range.

Postexercise ischemia is associated with increased neuropeptide Y in patients with coronary artery disease

BACKGROUND

Neurohormones may influence vascular tone both during and after exercise. Neuropeptide Y (NPY), which is costored and released with norepinephrine (NE) during sympathetic activity, is a potent vasoconstrictor with a relatively long half-life. We therefore examined its possible association with the ischemic response to exercise in patients with coronary artery disease.

METHODS AND RESULTS

Twenty-nine male patients with effort-induced angina pectoris underwent a symptom-limited exercise test. In addition to conventional ST-segment analysis, we examined ischemia on the basis of heart rate (HR)-adjusted ST-segment changes through calculation of the ST/HR slope during the final 4 minutes of exercise and of the ST/HR recovery loop after exercise. Blood samples were taken before, during, and after exercise for an analysis of several neurohormones. Mean ST-segment depression was -223+/-20.2 microV (P:<0.0001) just before the termination of exercise, followed by a gradual normalization, but it remained significant after 10 minutes (-49+/-8.9 microV, P:<0.0001). At the end of exercise, the ST/HR slope, which reflects myocardial ischemia, was -6.0+/-0.77 microV/HR. In most patients, ST-segment levels at a given HR were lower during recovery than during exercise, here referred to as ST "deficit." Exercise increased the plasma levels of NPY, NE, epinephrine, and N-terminal proatrial natriuretic peptide, but big endothelin remained unchanged. Although NE and epinephrine peaked at maximal exercise, the highest levels of NPY and N-terminal proatrial natriuretic peptide were observed 4 minutes after exercise. The maximal increase in the NPY correlated significantly with ST-segment depression at 3 minutes after exercise (r=-0.61, P:= 0.0005), the ST deficit at the corresponding time point (r=-0.66, P:= 0.0001), and the duration of ST-segment depression after exercise (r= 0.42, P:=0.02). In contrast, no such correlations were found for NE.

CONCLUSIONS

The present study has for the first time demonstrated a correlation between plasma NPY levels and the degree and duration of ST-segment depression after exercise in patients with coronary artery disease, which suggests that NPY may contribute to myocardial ischemia in these patients.

Contrasting cardiac regional responses of A-type and B-type natriuretic peptide to experimental chronic heart failure

OBJECTIVE

The aim of this study was to examine the regional myocardial variation in atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) synthesis during development of congestive heart failure (CHF).

METHODS

Heart failure was induced by left atrial rapid pacing for 3 weeks in pigs. The gene expression of ANP and BNP was measured by northern blot analysis and the peptide concentration in myocardial tissue and plasma by radioimmunoassay (RIA).

RESULTS

At the end of the pacing period pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) increased, and cardiac output (CO) decreased compared to sham-operated controls (PCWP: 17.6 +/- 1.9 vs. 3.1 +/- 0.9 mmHg) (RAP: 10.4 +/- 1.7 vs. 2.2 +/- 0.6 mmHg) (CO: 3.5 +/- 0.4 vs. 5.3 +/- 0.3 l/min), indicating a state of moderate to severe CHF. The gene expression and tissue concentration of BNP was low in sham pigs, but was strongly increased in all cardiac regions, and especially in the left ventricle, during CHF. In contrast, ANP was mainly produced in the atria both in normal and heart failure conditions. The relative increases in mRNA levels, tissue concentrations and circulating peptide concentrations were more profound for BNP than for ANP.

CONCLUSIONS

In response to CHF induction, ANP and BNP respond differently across the cardiac regions. Strong expression of the BNP gene was only found in the heart failure state, while ANP was clearly expressed also in the normal state. These findings support the concept of BNP being superior to ANP as a biochemical marker of CHF.

Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Prism adaptation in normal aging: slower adaptation rate and larger aftereffect

The effect of aging on prism adaptation, a motor learning paradigm, was evaluated. Different measures were obtained from a task consisting of throwing clay balls to a target in front of the subjects before, during, and after wearing prisms that deviate the visual field by several degrees. When performing the task without wearing the prisms, the aged subjects showed a larger hit variance, whereas the young subjects hit closer to the target. When donning the prisms, the aged group adapted more slowly than the controls, although after throwing all the balls both groups showed the same adaptation levels. After removing the prisms, the aged group showed a larger aftereffect. These findings suggest that the aftereffect requires the involvement of non-cognitive and cognitive processes and indicate that both adaptation and aftereffect are influenced by aging.

Cardiac natriuretic peptides and continuously monitored atrial pressures during chronic rapid pacing in pigs

Changes in atrial natriuretic peptide (ANP), N-terminal proatrial natriuretic peptide and brain natriuretic peptide (BNP) were evaluated in relation to continuously monitored atrial pressures in a pacing model of heart failure. Pigs were subjected to rapid atrial pacing (225 beats min-1) for 3 weeks with adjustments of pacing frequencies if the pigs showed overt signs of cardiac decompensation. Atrial pressures were monitored by a telemetry system with the animals unsedated and freely moving. Left atrial pressure responded stronger and more rapidly to the initiation of pacing and to alterations in the rate of pacing than right atrial pressure. Plasma natriuretic peptide levels were measured by radioimmunoassay and all increased during pacing with BNP exhibiting the largest relative increase (2.9-fold increase relative to sham pigs). Multiple regression analysis with dummy variables was used to evaluate the relative changes in natriuretic peptides and atrial pressures and the strongest correlation was found between BNP and left atrial pressure with R 2=0.81. Termination of pacing resulted in rapid normalization of ANP values in spite of persistent elevations in atrial pressures. This may reflect an increased metabolism or an attenuated secretory response of ANP to atrial stretch with established heart failure. In conclusion, 3 weeks of rapid pacing induced significant increases in atrial pressures and natriuretic peptide levels. All the natriuretic peptides correlated with atrial pressures with BNP appearing as a more sensitive marker of cardiac filling pressures than ANP and N-terminal proatrial natriuretic peptide.

The 2-piece Le Fort I osteotomy for cranial base access: an evaluation of 9 patients

PURPOSE

This article discusses the use of the 2-piece Le Fort I osteotomy to gain access to the cranial base and the authors' experiences with this technique.

METHODS

Medical records of patients who required surgical access to the cranial base were retrospectively reviewed, and demographic data, procedures done, postoperative results, and complications were recorded.

RESULTS

Nine patients underwent a 2-piece Le Fort I osteotomy. Complications included development of a pseudoaneurysm of the internal carotid artery in 1 patient, 2 cerebrospinal fluid leaks, both of which resolved, and 1 patient who lost 2 teeth and some associated bone.

CONCLUSION

The 2-piece Le Fort I osteotomy provides excellent access to the clival region of the cranial base with minimal complications.