Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V

PURPOSE

To review the importance of prognostic factors in developing new protocols for children with rhabdomyosarcoma (RMS).

PATIENTS AND METHODS

Four studies conducted by the Intergroup Rhabdomyosarcoma Study (IRS) Group from 1972 through 1991.

RESULTS

Favorable prognostic factors are: (1) undetectable distant metastases at diagnosis; (2) primary sites in the orbit and nonparameningeal head/neck and genitourinary nonbladder/prostate regions; (3) grossly complete surgical removal of localized tumor at the time of diagnosis; (4) embryonal/botryoid histology; (5) tumor size < or = 5 cm; and (6) age younger than 10 years at diagnosis. The IRS-V protocols are risk-based and refine therapy by reducing exposure to cyclophosphamide and radiation therapy (XRT) in patients at low risk while adding new, active agents such as topotecan or irinotecan to the standard therapy of vincristine, actinomycin D, and cyclophosphamide (VAC) plus XRT for patients with unfavorable histology or advanced disease. Collection of biologic specimens from patients with newly diagnosed disease continues to identify other factors that may distinguish patients with favorable features from those who need more intensive therapy. A new protocol that takes into account their previous treatment is needed for patients with recurrent disease. This program (being planned) does not include bone marrow/stem cell reconstitution because this strategy has thus far failed to improve survival rates of patients with metastases at diagnosis.

CONCLUSION

Better understanding of biologic differences and new, active agents are needed to improve outcome of patients with unfavorable features at presentation.

Cardiovascular drug-drug interactions

The drug-drug interactions discussed in this article have either documented or suspected clinical relevance for patients with cardiovascular disease and the clinician involved in the care of these patients. Oftentimes, drug-drug interactions are difficult, if not impossible, to predict because of the high degree of interpatient variability in drug disposition. Certain drug-drug interactions, however, may be avoided through knowledge and sound clinical judgment. Every clinician should maintain a working knowledge of reported drug-drug interactions and an understanding of basic pharmacokinetic and pharmacodynamic principles to help predict and minimize the incidence and severity of drug-drug interactions.

Does learning a complex task have to be complex? A study in learning decomposition

Many theories of skill acquisition have had considerable success in addressing the fine details of learning in relatively simple tasks, but can they scale up to complex tasks that are more typical of human learning in the real world? Some theories argue for scalability by making the implicit assumption that complex tasks consist of many smaller parts, which are learned according to basic learning principles. Surprisingly, there has been rather sparse empirical testing of this crucial assumption. In this article, we examine this assumption directly by decomposing the learning in the Kanfer-Ackerman Air-Traffic Controller Task (Ackerman, 1988) from the learning at the global level all the way down to the learning at the keystroke level. First, we reanalyze the data from Ackerman (1988) and show that the learning in this complex task does indeed reflect the learning of smaller parts at the keystroke level. Second, in a follow-up eye-tracking experiment, we show that a large portion of the learning at the keystroke level reflects the learning even at a lower, i.e., attentional level.

Bivalirudin: a new approach to anticoagulation

Bivalirudin is one of the first of a new class of anticoagulants known as direct thrombin inhibitors. These drugs are able to overcome many of the shortcomings of traditional heparin anticoagulation by virtue of this unique mechanism of action. Bivalirudin is a semisynthetic derivative of hirudin, a modified component of leech saliva. Hirudin has been plagued by bleeding complications, likely due to its high affinity for thrombin. Bivalirudin has lower thrombin affinity than hirudin and therefore is believed to be a much safer compound. Bivalirudin has been shown to be a very effective anticoagulant in laboratory models, though its clinical efficacy remains to be fully proven. Bivalirudin has been studied in the setting of coronary angioplasty, unstable angina, and acute myocardial infarction and has shown some promise in many of these settings, particularly in preventing complications of percutaneous coronary interventions. Bivalirudin has consistently shown less major bleeding compared with standard heparin, although limitations in study methodologies somewhat hinder an accurate interpretation of this finding. Larger-scale studies are indicated and are currently being performed, the results of which will more definitively define the role of bivalirudin for the treatment of cardiovascular disease.

Effects of changes in experimental design on PET studies of isometric force

Based on single-cell recordings in primates, the relationship between neuronal activity and force magnitude is thought to be monotonic, at least for a subset of pyramidal cells in the motor cortex. Functional neuroimaging studies have also suggested a monotonic relationship between cerebral activation and force magnitude. In order to more precisely define this relationship and to characterize the activation pattern(s) associated with the modulation of static force, we studied 40 normal subjects using [(15)O]water PET and a simple visuomotor task-application of static force on a micro force sensor with the thumb and index finger of the right hand. When our experimental design did not produce the expected result (evidence of a relationship between cerebral activation and force magnitude in ten subjects), we made serial changes in the experimental protocol, including the addition of control (baseline) trials, and increased the number of subjects in an effort to increase our sensitivity to variations in force magnitude. We compared univariate and multivariate data-analytic strategies, but we relied on our multivariate results to elucidate the interaction of attentional and motor networks. We found that increasing the number of subjects from 10 to 20 resulted in an increase in statistical power and a more stable (i.e., more replicable) but qualitatively similar result, and that the inclusion of control trials in a 10-subject group did not enhance our ability to discern significant brain-behavior relationships. Our results suggest that sample sizes greater than 20 may be required to detect parametric variation in some instances and that failure to detect such variation may result from unanticipated neurobehavioral effects.

The role of prefrontal cortex and posterior parietal cortex in task switching

Human ability to switch from one cognitive task to another involves both endogenous preparation without an external stimulus and exogenous adjustment in response to the external stimulus. In an event-related functional MRI study, participants performed pairs of two tasks that are either the same (task repetition) or different (task switch) from each other. On half of the trials, foreknowledge about task repetition or task switch was available. On the other half, it was not. Endogenous preparation seems to involve lateral prefrontal cortex (BA 46/45) and posterior parietal cortex (BA 40). During preparation, higher activation increases in inferior lateral prefrontal cortex and superior posterior parietal cortex were associated with foreknowledge than with no foreknowledge. Exogenous adjustment seems to involve superior prefrontal cortex (BA 8) and posterior parietal cortex (BA 39/40) in general. During a task switch with no foreknowledge, activations in these areas were relatively higher than during a task repetition with no foreknowledge. These results suggest that endogenous preparation and exogenous adjustment for a task switch may be independent processes involving different brain areas.

Multivariate predictive relationship between kinematic and functional activation patterns in a PET study of visuomotor learning

Imaging studies of visuomotor learning have reported practice-related activation in brain regions mediating sensorimotor functions. However, development and testing of functional motor learning models, based on the relationship between imaging and behavioral measures, is complicated by the multidimensional nature of motoric control. In the present study, multivariate techniques were used to analyze [15O]water PET and kinematic correlates of learning in a visuomotor tracing task. Fourteen subjects traced a geometric form over a series of eight tracing trials, preceded and followed by baseline trials in which they passively viewed the geometric form. Simultaneous evaluation of multiple behavioral measures indicated that performance improvement was most strongly associated with a global performance measure and least strongly associated with measures of fine motor control. Results of three independent analytic techniques (i.e., intertrial correlation matrices, power function modeling, iterative canonical variate analysis) indicated that imaging and behavioral measures were most closely related on early learning trials. Performance improvement was associated with covarying increases in normalized activity among superior parietal, postcentral gyrus, and premotor regions and covarying decreases in normalized activity among cerebellar, inferior parietal, pallidal, and medial occipital regions. These findings suggest that performance improvement may be associated with increased activation in neural systems previously implicated in visually guided reaching and decreased activation in neural systems previously implicated in attentive visuospatial processing.

Soft-tissue sarcomas of the diaphragm: a report from the Intergroup Rhabdomyosarcoma Study Group from 1972 to 1997

PURPOSE

To describe clinical details and outcome of children and adolescents with primary sarcomas of the diaphragm treated on Intergroup Rhabdomyosarcoma Studies (IRS) I through IV.

PATIENTS AND METHODS

We reviewed the records of 15 patients with sarcoma of the diaphragm who were entered on IRS Group protocols between 1972 and 1997. Patient ages at diagnosis ranged from 0.5 to 20 years (median, 13 yrs), and 10 were girls. Patients had chest pain, dyspnea, and/or coughing, decreased breath sounds, and occasionally hepatomegaly.

RESULTS

Localized, gross residual disease after initial surgery was present in 10 patients, and five had metastases at diagnosis (pleura, 3; pericardium, 1; lungs and bones, 1). Tumor subtypes were alveolar rhabdomyosarcoma (RMS) in five cases, embryonal RMS in three, undifferentiated sarcoma in three, extraosseous Ewing sarcoma in three, and unclassified sarcoma in one. Treatment consisted of radiation therapy to the primary tumor and metastases when feasible, and combination chemotherapy with vincristine, actinomycin D, and cyclophosphamide with or without doxorubicin, ifosfamide, cisplatin, and etoposide. Ten patients achieved complete remission (67%), four obtained a partial remission, and one was improved. Five patients (33%) are continuously failure-free and alive at a median of 8.8 years from diagnosis (range, 1.1-15 yrs). However, the other 10 patients experienced relapse at 0.3 to 2 years from start of therapy (median, 1 yr). Sites of relapse were local in five, distant in three, and combined in two. Death after relapse occurred at 0.39 to 2.6 years (median, 1.6 yrs) from diagnosis.

CONCLUSIONS

Sarcomas of the diaphragm are generally deemed unresectable at diagnosis and/or are metastatic. Most of them are not embryonal rhabdomyosarcomas. Treatment with more effective primary chemotherapy to shrink the tumor, followed-up by surgical resection and radiation therapy, should improve the prognosis for patients with sarcomas arising in the diaphragm, especially for the majority who have localized tumors.

Sleep, sleeping sites, and sleep-related activities: awakening to their significance

Since primates spend about half of their life at sleeping sites, knowledge of behavior in the vicinity of sleeping sites and analysis of factors influencing their use is important for understanding the diversity of primates' adaptations to their environment. The present paper reviews recent progress in the ethology and ecology of sleep in diurnal monkeys and apes. Emphasis is given to the following topics: safety from predators at sleeping sites, physical comfort, social behavior, and psychophysiology of sleep. In all cases, study at the group level and at the individual level can provide insights into behavioral adaptations. As well as increasing understanding of behavior in the wild, knowledge of sleep-related behavior can be applied with a view to improving the environment for captive primates.

Fabrication of topologically complex three-dimensional microfluidic systems in PDMS by rapid prototyping

This paper describes a procedure for making topologically complex three-dimensional microfluidic channel systems in poly(dimethylsiloxane) (PDMS). This procedure is called the "membrane sandwich" method to suggest the structure of the final system: a thin membrane having channel structures molded on each face (and with connections between the faces) sandwiched between two thicker, flat slabs that provide structural support. Two "masters" are fabricated by rapid prototyping using two-level photolithography and replica molding. They are aligned face to face, under pressure, with PDMS prepolymer between them. The PDMS is cured thermally. The masters have complementary alignment tracks, so registration is straightforward. The resulting, thin PDMS membrane can be transferred and sealed to another membrane or slab of PDMS by a sequence of steps in which the two masters are removed one at a time; these steps take place without distortion of the features. This method can fabricate a membrane containing a channel that crosses over and under itself, but does not intersect itself and, therefore, can be fabricated in the form of any knot. It follows that this method can generate topologically complex microfluidic systems; this capability is demonstrated by the fabrication of a "basketweave" structure. By filling the channels and removing the membrane, complex microstructures can be made. Stacking and sealing more than one membrane allows even more complicated geometries than are possible in one membrane. A square coiled channel that surrounds, but does not connect to, a straight channel illustrates this type of complexity.

Benefit of intensified therapy for patients with local or regional embryonal rhabdomyosarcoma: results from the Intergroup Rhabdomyosarcoma Study IV

PURPOSE

To compare failure-free survival (FFS) and survival for patients with local or regional embryonal rhabdomyosarcoma treated on the Intergroup Rhabdomyosarcoma Study (IRS)-IV with that of comparable patients treated on IRS-III.

PATIENTS AND METHODS

Patients were retrospectively classified as low- or intermediate-risk. Low-risk patients were defined as those with primary tumors at favorable sites, completely resected or microscopic residual, or orbit/eyelid primaries with gross residual disease and tumors less than 5 cm at unfavorable sites but completely resected. Intermediate-risk patients were all other patients with local or regional tumors.

RESULTS

Three-year FFS improved from 72% on IRS-III to 78% on IRS-IV for patients with intermediate-risk embryonal rhabdomyosarcoma (P =.02). Subset analysis revealed two groups that benefited most from IRS-IV therapy. FFS at 3 years for patients with resectable node-positive or unresectable (group III) embryonal rhabdomyosarcoma arising at certain favorable sites (head and neck [not orbit/eyelid or parameningeal] and genitourinary [not bladder or prostate]) improved from 72% on IRS-III to 92% on IRS-IV (P =.01). Similarly, 3-year FFS for patients with completely resected tumor or with only microscopic disease remaining (group I or II) at unfavorable sites improved from 71% on IRS-III to 86% on IRS-IV (P =.04). Only patients with unresectable embryonal rhabdomyosarcoma (group III) at unfavorable sites had no improvement in outcome on IRS-IV (3-year FFS for IRS-III and IRS-IV, 72% and 75%, respectively; P =.31).

CONCLUSION

IRS-IV therapy benefited certain subgroups of patients with intermediate-risk embryonal rhabdomyosarcoma. A doubling of the intensity of cyclophosphamide (or ifosfamide equivalent) dosing per cycle between IRS-III and IRS-IV is thought to be a key contributing factor for this improvement.

Learning and limits of use of eye gaze by capuchin monkeys (Cebus apella) in an object-choice task

The ability of 3 capuchin monkeys (Cebus apella) to use experimenter-given cues to solve an object-choice task was assessed. The monkeys learned to use explicit gestural and postural cues and then progressed to using eye-gaze-only cues to solve the task, that is, to choose the baited 1 of 2 objects and thus obtain a food reward. Increasing cue-stimulus distance and introducing movement of the eyes impeded the establishment of effective eye-gaze reading. One monkey showed positive but imperfect transfer of use of eye gaze when a novel experimenter presented the cue. When head and eye orientation cues were presented simultaneously and in conflict, the monkeys showed greater responsiveness to head orientation cues. The results show that capuchin monkeys can learn to use eye gaze as a discriminative cue, but there was no-evidence for any underlying awareness of eye gaze as a cue to direction of attention.

Late effects of therapy in 94 patients with localized rhabdomyosarcoma of the orbit: Report from the Intergroup Rhabdomyosarcoma Study (IRS)-III, 1984-1991

BACKGROUND

We reviewed the late complications of therapy in 94 patients with localized, primary rhabdomyosarcoma of the orbit treated on the Intergroup Rhabdomyosarcoma Study (IRS)-III protocol (1984-1991).

PROCEDURE

A questionnaire was sent to the institutions that had registered 106 patients with orbital RMS on the IRS-III protocol, seeking information about vision, periocular structures, and growth and development of the 102 survivors.

RESULTS

Ninety-four questionnaires were returned. The median follow-up interval was 7.6 years. The affected eye was removed from 13 patients because of local recurrence (N = 10) or other causes (N = 3). Seventy-nine of the eighty-one remaining patients had received radiation therapy. Sixty-five of these seventy-nine patients (82%) developed a cataract, and 43 of them (66%) underwent cataract surgery. Fifty-five patients (70%) had decreased visual acuity. Twenty-four patients had a dry eye, and 22 had chronic keratitis, conjunctivitis, or corneal changes. Strabismus, diplopia, retinopathy, and uveitis were uncommon. The orbit was hypoplastic in 48 of 82 patients assessed (59%). Ptosis and enophthalmos were reported in 22 patients. Decreased statural growth was noted in 13 of the 53 irradiated patients aged 3-14 years at diagnosis with sufficient data (24%).

CONCLUSIONS

The overall survival rate was 96% (102/106). The eye was preserved in 86% of the patients, but vision was impaired in 70% of them. Other frequent complications were cataract, orbital hypoplasia, keratoconjunctivitis, and ptosis/enophthalmos. The current IRS-V study recommends decreasing the dose of irradiation and using conformal techniques in an attempt to minimize these complications.

Omapatrilat: a unique new agent for the treatment of cardiovascular disease

Omapatrilat is the most clinically advanced of a new class of drugs, vasopeptidase inhibitors, which are being studied for the treatment of patients with cardiovascular disease. Omapatrilat inhibits the enzymatic activities of angiotensin-converting enzyme and neutral endopeptidase. The end result is blockade of angiotensin-II formation and inhibition of the catabolism of vasodilatory hormones, such as the natriuretic peptides, bradykinin, and adrenomedullin. Some of the ultimate pharmacologic effects include vasodilation, natriuresis, and diuresis, which may be beneficial in the management of various cardiovascular diseases, such as hypertension and heart failure. The pharmacokinetics of omapatrilat are compatible with once-daily dosing and a duration of antihypertensive efficacy of more than 24 hours. Omapatrilat decreases blood pressure in both high-renin and low-renin states, which suggests antihypertensive efficacy that is independent of the status of the renin-angiotensin system. Furthermore, the antihypertensive effect of omapatrilat is indiscriminate of age or race. Omapatrilat has consistently shown efficacy in decreasing both systolic and diastolic blood pressure to a similar or greater extent than either lisinopril or amlodipine; however, systolic pressure is more responsive to omapatrilat treatment than diastolic pressure. Although the role of omapatrilat in heart failure is still evolving, preliminary results are promising: hemodynamic improvements and clinical benefits of omapatrilat are similar or greater to those achieved with an angiotensin-converting enzyme inhibitor. Future studies (specifically the OVERTURE Study) will be of pivotal importance in establishing the role of omapatrilat in the treatment of patients with heart failure. The side-effect and drug-interaction profiles of omapatrilat are largely incomplete, but suggest excellent tolerability and a side-effect profile that is similar to placebo. Omapatrilat could be a revolutionary addition to the management of cardiovascular disease, and its clinical development will be followed closely by many who are curious if larger clinical trials will echo the impressive preliminary data that have been seen thus far.

Comparison of voxel- and volume-of-interest-based analyses in FDG PET scans of HIV positive and healthy individuals

Abnormal glucose metabolic patterns in the brain have been reported for HIV-1 seropositive (HIV+) patients when compared with seronegative healthy individuals. The metabolic covariance pattern obtained from voxel- or volume-of-interest (VOI)-based multivariate data analysis techniques can be used to characterize disease and potentially to detect and monitor disease progression in the early stage of AIDS dementia complex. However, the arbitrary smoothing typically applied to PET data during reconstruction and processing to reduce noise has an unknown effect on the data, especially for the voxel-based analysis.

METHODS

To investigate the impact of smoothing on a discrimination task, we applied principal component analysis with scaled subprofile-model preprocessing (SSM/PCA) followed by Fisher discriminant analysis to FDG PET data that were reconstructed and processed with different degrees of smoothing. Receiver operating characteristic curves were used to compare the ability of derived metabolic covariance patterns to discriminate HIV+ patients from healthy volunteers.

RESULTS

For the voxel-based analysis, we found that the spatial distribution of voxel weights from the SSM/PCA analysis suggested edge effects along major tissue and cerebrospinal fluid boundaries, indicative of a disease-specific pattern of cerebral atrophy for the HIV+ patients. In terms of its discrimination performance, this metabolic covariance pattern is stable and insensitive to a wide range of smoothing kernels, except for ramp reconstruction and Hanning reconstruction with 7 x 7 x 7 block smoothing. In these reconstructions, the discrimination performance decreased as a result of high image noise and excessive smoothing, respectively. Our results also indicated that if sufficient variance from the VOI measurements is included, the overall performance of a conventional VOI-based analysis can be similar to that of the voxel-based analysis for the same discrimination task. However, the VOI-based analysis performed poorly at low false-positive fraction and is less tolerant to noise in the metabolic covariance pattern than the voxel-based analysis.

CONCLUSION

We have obtained a unique covariance pattern of brain glucose metabolism for HIV+ patients compared with healthy volunteers. Discrimination based on this covariance pattern was found to be insensitive to a wide range of image smoothness.

Can squirrel monkeys (Saimiri sciureus) learn self-control? A study using food array selection tests and reverse-reward contingency

Eight squirrel monkeys (Saimiri sciureus) were presented with 2 stimulus arrays, namely 1 and 4 pieces of food, but they received only the array other than the one they reached for. In this reverse-reward condition, all monkeys initially showed a strong preference for the larger array. One monkey learned to reach toward the smaller array when a large-or-none reward contingency was applied (i.e., no reward followed a reach toward the larger array, but this array was given for a reach toward the smaller array). When correction trials and time-out were added to the large-or-none procedure, all remaining monkeys except 1 learned this form of self-control. Performance was maintained when correction trials were discontinued, the original reverse-reward condition was rerun, and novel array-size pairs were presented. This study demonstrates one form of self-control in a New World primate and shows the reverse-reward procedure to be a potentially valuable method for assessing species and individual differences in self-control and numerosity-related abilities.

Preoperative staging, prognostic factors, and outcome for extremity rhabdomyosarcoma: a preliminary report from the Intergroup Rhabdomyosarcoma Study IV (1991-1997)

BACKGROUND

During the fourth Intergroup Rhabdomyosarcoma (RMS) Study (IRS IV, 1991-97), a preoperative staging system was evaluated prospectively for the first time. The authors evaluated this staging system and the role of surgery in extremity RMS in contemporary multimodal therapy.

METHODS

A total of 139 patients (71 girls; median age, 6 years) were entered in IRS IV with extremity-site RMS. Stage was assigned by the IRSG Preoperative Staging System. Postsurgical group was determined by tumor status after initial surgical intervention. Multivariate analysis was performed using all pretreatment factors that were significant by univariate analysis, including clinical Group (i.e., I through IV), tumor invasiveness (T1,T2), nodal status (N0,N1), and tumor size (< or > or =5 cm). Failure-free survival rates (FFS) and survival rates were estimated using the Kaplan and Meier method.

RESULTS

Preoperative staging and clinical group distribution were as follows: Stage 2, n = 34; Stage 3, n = 73; Stage 4, n = 32; Group I, n = 31; Group II, n = 21; Group III, n = 54; Group IV, n = 33. Three-year FFS was 55%, and the overall survival rate was 70%. Eighty-seven patients had either unresectable, gross residual disease (Group III) or metastases (Group IV). FFS was significantly worse for these patients with advanced disease, compared with that for patients with complete resection or with only microscopic residual tumor (i.e., Group I or II; Group I, 3-year FFS, 91%; Group II, 72%; Group III, 50%; Group IV, 23%; P<.001). Lymph nodes were evaluated surgically in 76 patients with positive results in 38. Clinically, 13 additional patients had nodal disease. Both stage and group were highly predictive of outcome and were highly correlated. By multivariate analysis, none of the other variables were predictors of FFS.

CONCLUSIONS

This review confirms the utility of pretreatment staging for stratification of patients with extremity RMS with widely different risks of relapse, thereby paving the way for development of risk-based therapy. Group (operative staging) remains the most important predictor of FFS, emphasizing the importance of complete gross resection at initial surgical intervention, when feasible without loss of limb function. The high incidence of nodal disease in the patients who had lymph node biopsy confirms the need for surgical evaluation of lymph nodes to ensure accurate staging in children with extremity rhabdomyosarcoma.

Modeling the kinetics of acylation of insulin using a recursive method for solving the systems of coupled differential equations

This paper describes a theoretical method for solving systems of coupled differential equations that describe the kinetics of complicated reaction networks in which a molecule having multiple reaction sites reacts irreversibly with multiple equivalents of a ligand (reagent). The members of the network differ in the number of equivalents of reagent that have reacted, and in the patterns of sites of reaction. A recursive algorithm generates series, asymptotic, and average solutions describing this kinetic scheme. This method was validated by successfully simulating the experimental data for the kinetics of acylation of insulin.

Caries resistance in enamel by laser irradiation and topical fluoride treatment

PURPOSE

The purpose of this in vitro study was to compare caries resistance of sound human enamel following argon laser (AL) irradiation, as well as, combinations of topical fluoride foams and AL irradiation.

METHODS AND MATERIALS

Thirty extracted human teeth were sectioned into four buccal windows and assigned to one of the following treatment groups: (1) no treatment/control; (2) low fluence (11.5 J/cm2) AL irradiation for 10 seconds; (3) 1.23% APF foam for 4 minutes followed by low fluence AL irradiation; (4) 2.0% NaF foam for 4 minutes followed by low fluence AL irradiation. Caries-like lesions were created by submerging the teeth in ten Cate solution (pH 4.5). Following a 96-hour exposure period, 100 microns longitudinal sections were prepared for polarized light evaluation. Visilog 5.1.1. image analysis software was used to obtain quantitative lesion depths. The Scheffe F-test was used to compare the lesion depths for each of the four treatment groups.

RESULTS

Lesion depths were: 16.1 +/- 6 microns for control; 13.7 +/- 4 microns for AL irradiation alone; 12.1 +/- 4.3 microns for 1.23% APF foam before AL irradiation; and 11.4 +/- 5.9 microns for 2.0% NaF foam before AL irradiation. Significant difference (p < 0.05) was found between the control group and the 2.0% NaF foam before AL irradiation group. AL irradiation alone reduced lesion depth by 15% compared with the control lesion. When AL irradiation was combined with 1.23% APF foam treatment, lesion depth decreased by 25% compared with control lesions, and by 29% when combined with 2.0% NaF foam.

CONCLUSION

Combining AL irradiation and 2.0% NaF foam treatment significantly enhances the resistance of sound enamel to an in vitro cariogenic challenge.

Aggressive surgery is unwarranted for biliary tract rhabdomyosarcoma

BACKGROUND/PURPOSE

Rhabdomyosarcoma (RMS) of the biliary tract is rare, and, in addition to multiagent chemotherapy with or without radiotherapy (RT), some investigators recommend aggressive surgery. To assess the role of surgery, records of all 25 eligible patients with biliary RMS enrolled in IRSG studies I through IV from 1972 to 1998 were reviewed.

METHODS

Treatment included surgery with or without vincristine, dactinomycin, cyclophosphamide, doxorubicin, cisplatin, etoposide, ifosfamide, and with or without RT. Data evaluated included clinical presentation, treatment, complications, and outcome.

RESULTS

Diagnostic imaging identified the primary tumor but failed to identify regional metastases. Despite aggressive surgery, gross total resection at diagnosis was possible in only 6 cases, 2 of which had negative surgical margins. Although only 6 (29%) patients without distant metastases underwent gross total resection, estimated 5-year survival rate was 78% (95% CI 58%, 97%). Infectious complications were common and frequently associated with external biliary drains. Five (20%) died within the first 2 months, 3 of sepsis.

CONCLUSIONS

Surgery is critical for establishing an accurate diagnosis and determining the extent of regional disease. Gross total resection is rarely possible despite aggressive surgery, and outcome is good despite residual disease after surgery. External biliary drains increase the risk of postoperative infectious complications.

Fabrication of microfluidic systems in poly(dimethylsiloxane)

Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft-lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics-derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.

Fabrication of microfluidic systems in poly(dimethylsiloxane)

Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft-lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics-derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.

Can squirrel monkeys (Saimiri sciureus) learn self-control? A study using food array selection tests and reverse-reward contingency

Eight squirrel monkeys (Saimiri sciureus) were presented with 2 stimulus arrays, namely 1 and 4 pieces of food, but they received only the array other than the one they reached for. In this reverse-reward condition, all monkeys initially showed a strong preference for the larger array. One monkey learned to reach toward the smaller array when a large-or-none reward contingency was applied (i.e., no reward followed a reach toward the larger array, but this array was given for a reach toward the smaller array). When correction trials and time-out were added to the large-or-none procedure, all remaining monkeys except 1 learned this form of self-control. Performance was maintained when correction trials were discontinued, the original reverse-reward condition was rerun, and novel array-size pairs were presented. This study demonstrates one form of self-control in a New World primate and shows the reverse-reward procedure to be a potentially valuable method for assessing species and individual differences in self-control and numerosity-related abilities.

Strengthening HIV prevention: application of a research-to-practice framework

As the HIV epidemic continues to affect at-risk and vulnerable populations, providers strive to improve prevention programs, in part by seeking new interventions with greater effects. Although interventions with scientific evidence of effectiveness are vital to this effort, many challenges limit access to research products. We examine key challenges and offer a framework for moving research to practice, one in which research steps are linked to practice steps and all these activities take place in a complex and dynamic environment. The Replicating Effective Programs (REP) project of the Centers for Disease Control and Prevention and other technology transfer activities illustrate the operation of this framework for HIV prevention. Further actions to improve technology transfer are called for. These include reducing time from study design to practice; learning from field-based implementations; providing guidance about fidelity to, and tailoring of, science-based interventions; improving linkages among consumers, providers, and researchers; and seeking additional resources.

Survival after relapse in children and adolescents with rhabdomyosarcoma: A report from the Intergroup Rhabdomyosarcoma Study Group

BACKGROUND

Despite advances in therapy, nearly 30% of children with rhabdomyosarcoma experience progressive or relapsed disease, which is often fatal.

PATIENTS AND METHODS

To facilitate the development of a retrieval therapy protocol, we studied potential risk factors that were predictive of survival after first relapse in 605 children who were enrolled onto three consecutive Intergroup Rhabdomyosarcoma Study Group protocols.

RESULTS

The median survival time from first recurrence was 0.8 years; the estimated percentage of patients who survived 5 years from first recurrence was 17% +/- 2% (mean +/- SD). Univariate analysis showed that tumor histology was an important predictor of 5-year survival (P <.001): the 5-year survival rate was 64% for patients with botryoid tumors (n = 19), 26% for patients with embryonal tumors (n = 313), and 5% for patients with alveolar or undifferentiated sarcoma (n = 273). Further analysis identified prognostic factors within histologic subtypes (P <.001). For patients with embryonal tumors, the estimated 5-year survival rate was 52% for patients who initially presented with stage 1 or group I disease, 20% for those with stage 2/3 or group II/III disease, and 12% for those with group IV disease. For patients with stage 1/group I disease, estimated 5-year survival rates were higher for patients with local (72%) or regional (50%) recurrence than for those with distant (30%) recurrence. Among patients with alveolar or undifferentiated sarcoma, only the disease group predicted outcome: the 5-year survival estimate was 40% for group I versus 3% for groups II through IV. We identified a "favorable risk" group (approximately 20% of patients) whose 5-year estimated survival rate was near 50%; for all other patients, the estimated survival was near 10%.

CONCLUSION

This analysis demonstrates that the probability of 5-year survival after relapse for rhabdomyosarcoma is dependent on several factors at the time of initial diagnosis, including histologic subtype, disease group, and stage. These findings will form the basis of a multi-institutional risk-adapted relapse protocol for childhood rhabdomyosarcoma.

Indications for radiotherapy and chemotherapy after complete resection in rhabdomyosarcoma: A report from the Intergroup Rhabdomyosarcoma Studies I to III

PURPOSE

To evaluate the outcome of patients with rhabdomyosarcoma (RMS) treated with complete surgical resection and multiagent chemotherapy, with or without local radiotherapy (RT).

PATIENTS AND METHODS

Four hundred thirty-nine patients with completely resected (ie, group I) RMS were further treated with chemotherapy (vincristine and actinomycin D +/- cyclophosphamide, doxorubicin, and cisplatin) on Intergroup Rhabdomyosarcoma Studies (IRS) I to III between 1972 and 1991. Eighty-three patients (19%) also received local RT as a component of initial treatment.

RESULTS

Eighty-six patients relapsed (10-year failure-free survival [FFS] 79%, overall survival 89%). Six percent of failure sites were local, 6% were regional, and 7% were distant. Poor prognostic factors were tumor size greater than 5 cm, alveolar or undifferentiated histology, primary tumor sites other than genitourinary, and treatment on IRS-I or II. For patients with embryonal RMS who were treated with RT, there was a trend for improved FFS but no difference in overall survival. On IRS-I and II, patients with alveolar or undifferentiated sarcoma who received RT compared with those who did not receive RT had greater 10-year FFS rates (73% v 44%, respectively; P =.03) and overall survival rates (82% v 52%, respectively; (P =.02). Such patients who received RT on IRS III also benefited more than those who did not receive RT (10-year FFS, 95% v 69%; P =.01; overall survival, 95% v 86%; P =.23).

CONCLUSION

Patients with group I embryonal RMS have an excellent prognosis when treated with adjuvant multiagent chemotherapy without RT. Patients with alveolar RMS or undifferentiated sarcoma fare worse; however, FFS and overall survival are substantially improved when RT is added to multiagent chemotherapy (IRS-I and II). The best outcome occurred in IRS-III, when RT was used in conjunction with intensified chemotherapy.

Practice and retention: a unifying analysis

What is the strength of a memory trace that has received various practices at times tj in the past? The strength accumulation equation proposes the following: strength = sigma tj-d, where the summation is over the practices of the trace. This equation predicts both the power law of practice and the power law of retention. This article reports the fits of the predictions of this equation to 5 experiments. Across these experiments, participants received as many as 240 trials of practice distributed over intervals as long as 400 days. The experiments also varied whether participants were just practicing retrieving an item or practicing applying a relatively complex rule. A model based on this equation successfully fit all the data when it was assumed that the passage of psychological time slowed after the experimental session. The strength accumulation equation was compared with other conceptions of the retention function and the relationship of the retention function to the practice function.

Mutations in the skeletal muscle alpha-actin gene in patients with actin myopathy and nemaline myopathy

Muscle contraction results from the force generated between the thin filament protein actin and the thick filament protein myosin, which causes the thick and thin muscle filaments to slide past each other. There are skeletal muscle, cardiac muscle, smooth muscle and non-muscle isoforms of both actin and myosin. Inherited diseases in humans have been associated with defects in cardiac actin (dilated cardiomyopathy and hypertrophic cardiomyopathy), cardiac myosin (hypertrophic cardiomyopathy) and non-muscle myosin (deafness). Here we report that mutations in the human skeletal muscle alpha-actin gene (ACTA1) are associated with two different muscle diseases, 'congenital myopathy with excess of thin myofilaments' (actin myopathy) and nemaline myopathy. Both diseases are characterized by structural abnormalities of the muscle fibres and variable degrees of muscle weakness. We have identified 15 different missense mutations resulting in 14 different amino acid changes. The missense mutations in ACTA1 are distributed throughout all six coding exons, and some involve known functional domains of actin. Approximately half of the patients died within their first year, but two female patients have survived into their thirties and have children. We identified dominant mutations in all but 1 of 14 families, with the missense mutations being single and heterozygous. The only family showing dominant inheritance comprised a 33-year-old affected mother and her two affected and two unaffected children. In another family, the clinically unaffected father is a somatic mosaic for the mutation seen in both of his affected children. We identified recessive mutations in one family in which the two affected siblings had heterozygous mutations in two different exons, one paternally and the other maternally inherited. We also identified de novo mutations in seven sporadic probands for which it was possible to analyse parental DNA.

Expression of Bcl-2 and Bax in oligodendrogliomas and their relationship to apoptosis

Apoptotic bodies are frequently found in oligodendrogliomas, particularly in the anaplastic subtype. A range of proteins, such as those of the Bcl family, are implicated in the control of apoptosis. The ratio of antagonists of apoptosis, such as Bcl-2, to agonists, such as Bax, is thought to determine the outcome for a particular cell. This study aimed to determine the expression of Bcl-2 and Bax proteins in a series of oligodendrogliomas and to relate the expression of these to measures of apoptosis. Immunohistochemistry was used to detect the expression of Bcl-2 and Bax in an archival series of 32 oligodendrogliomas. The results were scored semiquantitatively for the extent and intensity of tumour staining. Apoptosis indices were determined by counting apoptotic bodies on haematoxylin and eosin staining and the percentage of cells showing a positive reaction with the TdT-mediated dUTP-biotin nick end-labelling technique (TUNEL). Granular cytoplasmic staining for Bcl-2 was seen in tumour cells in 81% of cases. Cases with a strong intensity (but not extent) of staining showed a lower TUNEL index (P=0.038). Bcl-2 expression was identified in the walls of intratumoural blood vessels in 55% of cases and in peri-tumoural neurones (where present) in 87%. Bax expression was detected in tumour cells in 69% of cases but no relationship to TI was detected. Bax positivity was seen in blood vessels in 44% of cases and peri-tumoural neurones in 60%. Bcl-2 and Bax were concluded to be expressed in a high proportion of oligodendrogliomas, suggesting that they may exert a regulatory role in cell death in these tumours.

Plurality and resemblance in fMRI data analysis

We apply nine analytic methods employed currently in imaging neuroscience to simulated and actual BOLD fMRI signals and compare their performances under each signal type. Starting with baseline time series generated by a resting subject during a null hypothesis study, we compare method performance with embedded focal activity in these series of three different types whose magnitudes and time courses are simple, convolved with spatially varying hemodynamic responses, and highly spatially interactive. We then apply these same nine methods to BOLD fMRI time series from contralateral primary motor cortex and ipsilateral cerebellum collected during a sequential finger opposition study. Paired comparisons of results across methods include a voxel-specific concordance correlation coefficient for reproducibility and a resemblance measure that accommodates spatial autocorrelation of differences in activity surfaces. Receiver-operating characteristic curves show considerable model differences in ranges less than 10% significance level (false positives) and greater than 80% power (true positives). Concordance and resemblance measures reveal significant differences between activity surfaces in both data sets. These measures can assist researchers by identifying groups of models producing similar and dissimilar results, and thereby help to validate, consolidate, and simplify reports of statistical findings. A pluralistic strategy for fMRI data analysis can uncover invariant and highly interactive relationships between local activity foci and serve as a basis for further discovery of organizational principles of the brain. Results also suggest that a pluralistic empirical strategy coupled formally with substantive prior knowledge can help to uncover new brain-behavior relationships that may remain hidden if only a single method is employed.

Practice and retention: a unifying analysis

What is the strength of a memory trace that has received various practices at times tj in the past? The strength accumulation equation proposes the following: strength = sigma tj-d, where the summation is over the practices of the trace. This equation predicts both the power law of practice and the power law of retention. This article reports the fits of the predictions of this equation to 5 experiments. Across these experiments, participants received as many as 240 trials of practice distributed over intervals as long as 400 days. The experiments also varied whether participants were just practicing retrieving an item or practicing applying a relatively complex rule. A model based on this equation successfully fit all the data when it was assumed that the passage of psychological time slowed after the experimental session. The strength accumulation equation was compared with other conceptions of the retention function and the relationship of the retention function to the practice function.

Process, not representation: reply to Radvansky (1999)

The size of fan effects is determined by processes at retrieval, not by whether or not information is represented as situations. Evidence contradicts G. A. Radvansky's (1999) claim that time to retrieve information from a situation does not depend on the number of elements in the situation. Moreover, Radvansky's principles for ascribing situational models to experiments appear to be post hoc ways of redescribing the data. On the other hand, the evidence does support the Adaptive Control of Thought--Rational (ACT-R) assumption that participants can adjust their attentional weightings and so produce differential fan effects. Moreover, the ACT-R theory of the fan effect is consistent with many other findings.

Comparison of matched BOLD and FAIR 4.0T-fMRI with [15O]water PET brain volumes

Valid comparisons of functional activation volumes from fMRI and PET require accurate registration, matched spatial resolution, and if possible matched noise. We coregistered 4.0T-fMRI and PET volumes, using a series of linear and nonlinear transformations applied to the PET volumes. Because of the limited number of fMRI slices that were available, PET volumes were transformed to the fMRI space. Since 4.0T-fMRI and 4.0T-MRI volumes have significant spatial distortion due to magnet inhomogeneities, high resolution 1.5T-MRI volumes were nonlinearly transformed to 4.0T-MRI volumes as part of the transformation chain. The smoothing effects of these registration transformations were measured, in order to match the spatial resolution of the coregistered fMRI and PET volumes. Spatial resolution of the transformed PET volumes in the fMRI space was degraded by up to 60% due to the transformation process. Due to both the image acquisition characteristics and the coregistration process, the transformed PET volumes had a spatial resolution that was lower than that of tMRI. Therefore, significant smoothing of fMRI volumes was necessary to match their spatial resolution with that of the transformed PET volumes. Matching the spatial resolution of the fMRI volumes to those of the transformed PET volumes was achieved by matching the shape of their point spread functions. In order to do this, Gaussian kernels were employed to smooth the fMRI volumes. We were unable to simultaneously match the resolution and noise of fMRI and PET signals in the motor cortex. Activation maps derived from transformed PET and smoothed fMRI volumes were compared. Contralateral motor cortex was active in all modalities but there were large variations in the size of the activated region and its signal to noise ratio across BOLD, FAIR, and PET images within each subject. Nevertheless, the relative CBF changes measured by FAIR were consistent with those determined by PET.

Marginal zone B-cell lymphoma: A clinical comparison of nodal and mucosa-associated lymphoid tissue types. Non-Hodgkin's Lymphoma Classification Project

PURPOSE

In the International Lymphoma Study Group classification of lymphoma, extranodal marginal zone B-cell lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT) type is listed as a distinctive entity. However, nodal MZL is listed as a provisional entity because of questions as to whether it is truly a disease or just an advanced stage of MALT-type MZL. To resolve the issue of whether primary nodal MZL without involvement of mucosal sites exists and whether it is clinically different from extranodal MALT-type lymphoma, we compared the clinical features of these two lymphomas.

PATIENTS AND METHODS

Five expert hematopathologists reached a consensus diagnosis of MZL in 93 patients. Seventy-three were classified as having MALT-type MZL because of involvement of a mucosal site at the time of diagnosis, and 20 were classified as having nodal MZL because of involvement of lymph nodes without involvement of a mucosal site.

RESULTS

A comparison of the clinical features of nodal MZL and MALT-type MZL showed that more patients with nodal MZL presented with advanced-stage disease (71% v 34%; P =. 02), peripheral lymphadenopathy (100% v 8%; P <.001), and para-aortic lymphadenopathy (56% v 14%; P <.001) than those with MALT-type MZL. However, fewer patients with nodal MZL had a large mass (> or = 5 cm) than those with MALT-type MZL (31% v 68%; P =.03). The 5-year overall survival of patients with nodal MZL was lower than that for patients with MALT-type MZL (56% v 81%; P =.09), with a similar result for failure-free survival (28% v 65%; P =.01). Comparisons of patients with International Prognostic Index scores of 0 to 3 showed that those with nodal MZL had lower 5-year overall survival (52% v 88%; P =.025) and failure-free survival (30% v 75%; P =.007) rates than those with MALT-type MZL.

CONCLUSION

Nodal MZL seems to be a distinctive disease entity rather than an advanced stage of MALT-type MZL because the clinical presentations and survival outcomes are different in these two types of MZL. Clinically, nodal MZL is similar to other low-grade, node-based B-cell lymphomas, such as follicular and small lymphocytic lymphomas.

Study of cavernosal arterial anatomy using color and power Doppler sonography: impact on hemodynamic parameter measurement

PURPOSE

We report on color and power Doppler ultrasound to study cavernosal arterial anatomy, and evaluate the impact of vascular anatomy on the measurement of hemodynamic parameters.

MATERIALS AND METHODS

Cavernosal arterial anatomy of 42 patients with erectile dysfunction was evaluated using color and power Doppler ultrasound. A computerized waveform analysis was used to measure peak systolic velocity, end diastolic velocity and resistive indexes at various sites, including the penile crura, and proximal mid and distal penile shaft. Hemodynamic parameters were measured in each artery in cases of bifurcated or multiple cavernosal arteries.

RESULTS

A total of 80 corpora were adequately evaluated. We observed a single artery without major proximal branches in 37 corpora, a single artery with major proximal branches in 17, bifurcated arteries in 15, 2 cavernosal arteries in 4 and marked arterial tortuosity in 1. In 6 corpora the main cavernosal artery arose from the superficial dorsal artery. The peak systolic velocity was highest at the proximal and decreased progressively at the distal site. The peak systolic velocity plus or minus standard deviation at the mid shaft averaged 69.3+/-30.0% of that at the proximal penile shaft. Of the 15 corpora with bifurcated arteries 67% had a 40% or greater difference in peak systolic velocity between the branches. Complete or partial occlusion of the cavernosal artery was identified in 3 corpora, and a dramatic difference in peak systolic velocity proximal and distal to the stenotic area was demonstrated.

CONCLUSIONS

Cavernosal arterial anatomy is variable and hemodynamic parameters differ at various sites of measurement. Parameters should be measured at a consistent proximal site to obtain a reliable assessment. Variations in vascular anatomy and cavernosal artery pathology should be considered when interpreting color Doppler sonography and before penile vascular surgery.

Process, not representation: reply to Radvansky (1999)

The size of fan effects is determined by processes at retrieval, not by whether or not information is represented as situations. Evidence contradicts G. A. Radvansky's (1999) claim that time to retrieve information from a situation does not depend on the number of elements in the situation. Moreover, Radvansky's principles for ascribing situational models to experiments appear to be post hoc ways of redescribing the data. On the other hand, the evidence does support the Adaptive Control of Thought--Rational (ACT-R) assumption that participants can adjust their attentional weightings and so produce differential fan effects. Moreover, the ACT-R theory of the fan effect is consistent with many other findings.