A method for recording behavior and multineuronal CNS activity from tethered insects flying in virtual space

We describe a low cost, novel virtual reality-based insect flight simulator that combines visual, olfactory and mechanosensory stimuli with multichannel neurophysiological recording techniques. Three-dimensional visual environments were created using customized modifications of a first person flight simulator computer game. Experiments could be performed in open-loop, where the flying insect's movement through the environment is 'driven' by the human operator, or in closed-loop where the movement of the environment is controlled by optically sensed movements of the insect's abdomen. During flight, we recorded multineuronal activity from the ventral nerve cord between the brain and thoracic ganglia. Results show that in open-loop conditions, induced turns of the environment evoked characteristic compensatory optomotor responses. Coordination of wing and body kinematics was similar to that observed in free flight. In closed-loop conditions, the insect was able to navigate through the simulated environment and produce flight tracks in response to presentation of pheromone that resemble those observed in free flight. We discuss the effectiveness of this preparation and its utility for addressing specific questions of insect flight as well as general questions in neuroethology.

Emotional modulation of cognitive control: approach-withdrawal states double-dissociate spatial from verbal two-back task performance

Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach-withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion-cognition interactions.

Paclitaxel and carboplatin adjuvant therapy alone or with radiotherapy for resected nonsmall cell lung carcinoma: a feasibility study of the Minnie Pearl Cancer Research Network

BACKGROUND

The objective of this study was to determine the feasibility and toxicity of paclitaxel and carboplatin given in the adjuvant setting alone for patients with resected Stage IB disease and combined with radiotherapy for patients with resected Stages II and IIIA disease and selected patients with Stage IIIB and IV disease (Revised International System for Staging of Lung Cancer).

METHODS

One hundred two patients with resected nonsmall cell lung carcinoma were treated in the postoperative period with 3 courses of paclitaxel 200 mg/m(2) intravenously (i.v.) over 1 hour and carboplatin area under the curve of 6 i.v. every 3 weeks for 3 courses. Patients with Stage IB received no further therapy, and those with higher stages also subsequently received radiotherapy plus concurrent weekly paclitaxel and carboplatin over 6 weeks. The median age was 61 years, with 56 men and 46 women, and the predominant histologic type was adenocarcinoma. Twenty pneumonectomies, 80 lobectomies, and 2 other procedures were performed. Ninety percent of the patients (92 of 102) received all 3 courses of adjuvant paclitaxel and carboplatin (84% received full doses). Seventy-three percent received full doses of radiotherapy and concurrent weekly chemotherapy (49 of 67 patients), and 14 others received greater than 75% of the radiotherapy and concurrent chemotherapy.

RESULTS

Toxicity of the chemotherapy was mild with only three hospitalizations for neutropenia and fever and no treatment-related deaths. Severe hypersensitivity occurred in six patients (6%). Concurrent radiation therapy and weekly chemotherapy also was well tolerated with the exception of Grade 3-4 esophagitis observed in 27% (17 of 67 patients). Follow-up was short with a median of 10 months, and 65% of all patients remained progression free.

CONCLUSIONS

Three courses of paclitaxel and carboplatin is tolerable, feasible, and can be delivered in most patients in the adjuvant setting. Subsequently, in higher stage patients, concurrent postoperative radiation therapy and weekly paclitaxel and carboplatin is well tolerated and delivered in most patients. Definitive prospective randomized Phase III adjuvant trials are warranted.

Emotional modulation of cognitive control: approach-withdrawal states double-dissociate spatial from verbal two-back task performance

Emotional states might selectively modulate components of cognitive control. To test this hypothesis, the author randomly assigned 152 undergraduates (equal numbers of men and women) to watch short videos intended to induce emotional states (approach, neutral, or withdrawal). Each video was followed by a computerized 2-back working memory task (spatial or verbal, equated for difficulty and appearance). Spatial 2-back performance was enhanced by a withdrawal state and impaired by an approach state; the opposite pattern held for verbal performance. The double dissociation held more strongly for participants who made more errors than average across conditions. The results suggest that approach-withdrawal states can have selective influences on components of cognitive control, possibly on a hemispheric basis. They support and extend several frameworks for conceptualizing emotion-cognition interactions.

Anterior cingulate cortex and response conflict: effects of frequency, inhibition and errors

Anterior cingulate cortex (ACC) may play a key role in cognitive control by monitoring for the occurrence of response conflict (i.e. simultaneous activation of incompatible response tendencies). Low-frequency responding might provide a minimal condition for eliciting such conflict, as a result of the need to overcome a prepotent response tendency. We predicted that ACC would be selectively engaged during low-frequency responding, irrespective of the specific task situation. To test this hypothesis, we examined ACC activity during the performance of simple choice-discrimination tasks, using rapid event-related functional magnetic resonance imaging. Subjects were scanned while performing three tasks thought to tap different cognitive processes: 'Go/No-go' (response inhibition), 'oddball' (target detection), and two-alternative forced- choice (response selection). Separate conditions manipulated the frequency of relevant task events. Consistent with our hypothesis, the same ACC region was equally responsive to low-frequency events across all three tasks, but did not show differential responding when events occurred with equal frequency. Subregions of the ACC were also identified that showed heightened activity during the response inhibition condition, and on trials in which errors were committed. Task-sensitive activity was also found in right prefrontal and parietal cortex (response inhibition), left superior temporal and tempoparietal cortex (target detection), and supplementary motor area (response selection). Taken together, the results are consistent with the hypothesis that the ACC serves as a generic detector of processing conflict arising when low-frequency responses must be executed, but also leave open the possibility that further functional specialization may occur within ACC subregions.

Activity of descending contralateral movement detector neurons and collision avoidance behaviour in response to head-on visual stimuli in locusts

We recorded the activity of the right and left descending contralateral movement detectors responding to 10-cm (small) or 20-cm (large) computer-generated spheres approaching along different trajectories in the locust's frontal field of view. In separate experiments we examined the steering responses of tethered flying locusts to identical stimuli. The descending contralateral movement detectors were more sensitive to variations in target trajectory in the horizontal plane than in the vertical plane. Descending contralateral movement detector activity was related to target trajectory and to target size and was most sensitive to small objects converging on a direct collision course from above and to one side. Small objects failed to induce collision avoidance manoeuvres whereas large objects produced reliable collision avoidance responses. Large targets approaching along a converging trajectory produced steering responses that were either away from or toward the side of approach of the object, whereas targets approaching along trajectories that were offset from the locust's mid-longitudinal body axis primarily evoked responses away from the target. We detected no differences in the discharge properties of the descending contralateral movement detector pair that could account for the different collision avoidance behaviours evoked by varying the target size and trajectories. We suggest that descending contralateral movement detector properties are better suited to predator evasion than collision avoidance.

Carcinoma of unknown primary site

BACKGROUND

The long term survival and toxicity associated with the chemotherapy combination of paclitaxel, carboplatin, and extended-schedule etoposide used for the treatment of patients with metastatic carcinoma of unknown primary site were evaluated.

METHODS

Seventy-one patients were treated between March 1995 and November 1996 with paclitaxel, carboplatin, and oral etoposide every 21 days. Stable or responding patients received four to eight courses of therapy. The following histologies were represented: well differentiated adenocarcinoma (34 patients); poorly differentiated adenocarcinoma or poorly differentiated carcinoma (30 patients); poorly differentiated neuroendocrine carcinoma (6 patients); and squamous cell carcinoma (1 patient).

RESULTS

Forty-eight percent of assessable patients had major responses to therapy (95% confidence interval, 39%-55%), and 10 patients (15%) had complete responses. There were no response differences among the major histologic types. The median survival for all 71 patients was 11 months, and the 1-year, 2-year, and 3-year survival rates were 48%, 20%, and 14%, respectively. The minimum follow-up period was 34 months (range, 34-50 mos). The regimen was tolerated well with no treatment-related deaths and only 12 hospitalizations for neutropenia and fever. There was no serious long term toxicity.

CONCLUSIONS

In this large Phase II trial, the combination of paclitaxel, carboplatin, and oral etoposide produced major responses or stable disease status in nearly 80% of patients who had carcinoma of unknown primary site. The median survival and 1-year, 2-year, and 3-year survival rates were noteworthy. The current study obtained similar or superior results to those seen with chemotherapy for many other groups of patients, such as those who had well defined advanced malignancies, those who were considered to have responsive tumors, and those who had obtained substantial benefits from cytotoxic therapy. Although the regimen reported in the current study can become an attractive option for many patients with carcinoma of unknown primary site, there remains a need for further clinical trials.

In vivo enhancement of chemotherapy with static electric or magnetic fields

We evaluated the ability of both static electric and static magnetic fields to enhance the in vivo action of a chemotherapeutic agent, adriamycin, against transplanted mammary tumors in mice. Female B6C3F1 mice with transplanted mammary adenocarcinoma were divided into four randomized groups and injected with 10 mg/kg adriamycin on day 7 of the study. Three of the groups were then exposed to nonuniform static electric or static magnetic fields. The resulting tumor regression in each group was measured four times during the remaining 13 days of the 20 day study. Two-sided statistical tests revealed all of the static field exposed groups achieved significantly greater (P </=.05) tumor regression than the group treated with adriamycin only, with P-values in a range as low as. 0001. There is an almost universal need in disease treatment to increase the efficacy and delivery of bioactive agents against target cells. The technology demonstrated here may result in improved use of therapeutic materials ranging from drugs to genetic agents. In addition, our findings point to possible hazards from the in vivo enhancing action of static fields on administered or environmentally encountered chemicals.

Preoperative combined modality therapy with paclitaxel, carboplatin, prolonged infusion 5-fluorouracil, and radiation therapy in localized esophageal cancer: preliminary results of a Minnie Pearl Cancer Research Network phase II trial

PURPOSE

To evaluate the feasibility, toxicity, and therapeutic efficacy of 1-hour paclitaxel, carboplatin, continuous low-dose infusional 5-fluorouracil, and concurrent radiation therapy administered preoperatively in patients with localized esophageal cancer.

PATIENT AND METHODS

Forty-nine patients with localized esophageal cancer, of either squamous cell carcinoma or adenocarcinoma histology, were enrolled into this phase II trial. All patients were candidates for surgical resection and received the following neoadjuvant therapy: paclitaxel, 200 mg/m2, 1 hour IV on days 1 and 22; carboplatin, AUC 6.0, IV on days 1 and 22; 5-fluorouracil, 225 mg/m2/day, continuous IV infusion on days 1 to 42; and radiation therapy, 45 Gy, administered by 1.8-Gy daily fractions beginning on day 1 of chemotherapy. Upon completion of this neoadjuvant regimen, patients were reevaluated, and all responding patients were resected within 6 weeks of completing neoadjuvant treatment.

RESULTS

Administration of this combined modality regimen was associated with moderate toxicity and was tolerated by most patients. Leukopenia (65%) and esophagitis (31%) were the most common toxicities. Most patients did not require nutritional support. There were no treatment-related deaths during neoadjuvant therapy; however, three patients (9%) experienced postoperative death. Preliminary assessment of treatment efficacy is encouraging, with 17 of 37 evaluable patients (46%) achieving pathologic complete remission and an additional 11 patients (30%) having only microscopic residual disease.

CONCLUSIONS

This novel, combined-modality neoadjuvant approach for the treatment of localized esophageal carcinoma is feasible and can be administered with toxicity that compares favorably to previously reported neoadjuvant regimens containing high-dose cisplatin. Preliminary assessment of efficacy is also encouraging, with 46% of patients having pathologic complete response. Further follow-up and larger numbers of patients are required to assess efficacy more definitively.

Effect of RenaGel, a non-absorbed, calcium- and aluminium-free phosphate binder, on serum phosphorus, calcium, and intact parathyroid hormone in end-stage renal disease patients

BACKGROUND

Control of dietary phosphate absorption in end-stage renal disease patients is essential to prevent the deleterious sequelae of phosphorus retention. Efficacy of currently available calcium- and aluminium-containing phosphate binders is constrained by the side-effects associated with the absorption of calcium and aluminium. The current study examined the efficacy of RenaGel, a calcium- and aluminium-free, polymeric phosphate binder, in end-stage renal disease patients.

METHODS

Administration of calcium- or aluminium-containing phosphate binders ceased during a 2-week washout period. RenaGel, at starting doses of one, two, or three 500-mg capsules three times per day with meals, was administered for 8 weeks. RenaGel dose was titrated up 1 capsule per meal at the end of each 2-week period if necessary to achieve phosphorus control. A second 2-week washout period followed the end of RenaGel treatment.

RESULTS

Mean serum phosphorus rose from a pre-washout level of 6.9 mg/dl (2.23 mmol/l) to 8.1 mg/dl (2.62 mmol/l) at the end of the initial 2-week washout. With RenaGel treatment, serum phosphorus declined and returned to pre-washout levels after 4 weeks. Serum phosphorus reached a nadir of 6.5 mg/dl (2.10 mmol/l) after 7 weeks of RenaGel treatment. Serum phosphorus rose to 8.2 mg/dl (2.65 mmol/l) 2 weeks after cessation of RenaGel treatment. As anticipated, calcium declined during the initial washout period when calcium-based phosphate binders were stopped for the majority of patients. The rise in serum phosphorus and decline in serum calcium during washout resulted in an increase in median intact parathyroid hormone (iPTH) levels from 292 pg/ml to 395 pg/ml. iPTH fell to 283 pg/ml after 6 weeks of RenaGel treatment despite a persistently lower serum calcium. RenaGel treatment also reduced serum total and LDL cholesterol by 25 mg/dl (0.65 mmol/l) and 23 mg/dl (0.59 mmol/l) respectively.

CONCLUSIONS

RenaGel appears to be an effective phosphate binder free of calcium and aluminium. Phosphorus control with two to four RenaGel capsules per meal appears to result in comparable phosphorus lowering seen with calcium- or aluminium-based phosphate binders. RenaGel may offer an alternative for the control of phosphorus retention in end-stage renal disease patients.

Life expectancy in British Marfan syndrome populations

A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970-1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3+/-16.5 years. 50% median cumulative survival in the total cohort (n=206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome.

Paclitaxel, carboplatin, and extended-schedule etoposide in the treatment of small-cell lung cancer: comparison of sequential phase II trials using different dose-intensities

PURPOSE

In two sequential phase II studies, we evaluate the feasibility and efficacy of adding paclitaxel to a standard platinum/etoposide regimen in the first-line treatment of small-cell lung cancer.

PATIENTS AND METHODS

One hundred seventeen patients with small-cell lung cancer were treated between June 1993 and July 1996. The first 38 patients received a lower-dose regimen: paclitaxel 135 mg/m2 by 1-hour infusion, carboplatin at an area under the concentration-time curve (AUC) of 5.0, and etoposide 50 mg alternating with 100 mg orally on days 1 to 10. When only mild myelosuppression was observed, doses of paclitaxel and carboplatin were increased in the subsequent 79 patients (paclitaxel 200 mg/m2 by 1-hour infusion and carboplatin at an AUC of 6.0). All patients received four courses of treatment, administered at 21-day intervals. Patients with limited-stage small-cell lung cancer also received thoracic radiation therapy (1.8 Gy/d; total dose, 45 Gy) administered concurrently with courses 3 and 4 of chemotherapy.

RESULTS

Seventy-two of 79 patients (91%) who receive the higher-dose regimen had major responses. Thirty-two of 38 (84%) with extensive-stage disease responded (21% complete response rate); median survival was 10 months for this group. With limited-stage disease, the overall response rate was 98%, with 71% complete responses; the median survival time has not been reached at 16 months. Median survival in extensive-stage patients was longer in patients who received the higher-dose regimen (10 months) than in the previous group treated with lower doses (7 months; P = .008). The higher-dose regimen was well tolerated, with myelosuppression being the major toxicity. Compared with the lower-dose regimen, grade 3/4 neutropenia increased from 8% to 38% of courses, but the incidence of hospitalization for neutropenia and fever did not increase. Other nonhematologic toxicities were uncommon, and did not increase substantially with the higher-dose regimen.

CONCLUSION

Paclitaxel can be added at full dose (200 mg/m2) to a carboplatin/etoposide combination while maintaining a tolerable toxicity profile. Median survival times in both extensive- and limited-stage patients compare favorably with other reported regimens. This regimen merits further investigation, and a randomized trial to compare this regimen with a standard carboplatin/etoposide combination is underway.

Comparison of preoperative characteristics of men and women undergoing coronary artery bypass grafting (the Post Coronary Artery Bypass Graft [CABG] Biobehavioral Study)

A cohort of 759 coronary artery bypass grafting (CABG) patients (269 women and 490 men) was enrolled in the prospective POST CABG Biobehavioral Study at 5 clinical centers in the United States and Canada. Sociodemographic and medical data were obtained by interview and from medical charts. Health-related quality of life and psychosocial data were ascertained preoperatively by interview and questionnaire for those patients whose condition allowed preoperative assessment and was compared among patients from hospitals enrolling both male and female patients (143 women and 267 men). Women enrolled in the Biobehavioral Study were older than men (65.4 +/- 9.0 vs 61.8 +/- 9.7 years, p < 0.001) and more likely to have a preoperative medical condition which precluded biobehavioral evaluation (47% vs 34%, p < 0.001). Women were less likely to be high school graduates (59% vs 74%, p < 0.001), were less likely to be earning > or = $25,000 per year (39% vs 69%, p < 0.001), and were married less often at the time of surgery (59% vs 85%, p < 0.001). Fewer women than men were able to perform basic self-care activities (p < 0.001) and social activities (p < 0.001). Women were also less able to perform the more demanding activities required for independent living, recreation, and maintaining a household (p < 0.001). Women were also more anxious (p = 0.01) and reported more depressive symptoms (p < 0.001) than men. These data suggest that plans for perioperative and convalescent care for women undergoing CABG should take into account their less favorable medical and psychosocial status relative to men.

The tumor conference: an integral component of the oncology program

This periodic meeting of individuals with oncologic expertise represents the best that modern medicine can be: a true multidisciplinary approach to patient care. Nowhere else in healthcare will you find a better example of combining different expertise for the express purpose of improving the delivery of care for an individual patient.

A clinical severity grading scale for Marfan syndrome

There is considerable interest in assessing patients with Marfan syndrome at the clinical, protein, and genetic levels. Clinical assessments are inconsistent between centres and between clinicians. There are no satisfactory clinical grading scales against which to analyse the molecular information, limiting the scope of clinical/ molecular correlations. We present grading scales for the major clinical systems involved in Marfan syndrome and suggest that their widespread use will facilitate collaborative approaches to clinical/ molecular correlations and international assessments of therapy.

Paclitaxel in combination chemotherapy with radiotherapy in patients with unresectable stage III non-small-cell lung cancer

PURPOSE

The addition of combination chemotherapy to standard radiation therapy has improved treatment for locally unresectable non-small-cell lung cancer. In this phase II study, we evaluated the toxicity and efficacy of a novel chemotherapy regimen that included paclitaxel, cisplatin, and etoposide plus concurrent radiation therapy in this group of patients.

PATIENTS AND METHODS

Thirty-three patients with previously untreated, unresectable stage III non-small-cell lung cancer (stage IIIA, 11 patients; stage IIIB, 22 patients) initially received two courses of chemotherapy, which included paclitaxel 135 mg/m2 by 1-hour infusion on day 1, cisplatin 60 mg/m/ intravenously (i.v.) on day 2, and etoposide 100 mg/m2 i.v. on days 1, 2 and 3. On week 6, radiation therapy (60 Gy in 30 fractions) was initiated in conjunction with two additional courses of chemotherapy: paclitaxel 135 mg/m2 i.v. by 1-hour infusion on day 1, cisplatin 5 mg/m2 i.v. on days 2- to 10, and etoposide 25 mg/m2 on days 1 to 10.

RESULTS

This combined modality program was feasible and well tolerated by most patients. During the two courses of induction chemotherapy, grade 3 or 4 myelosuppression occurred in only six patients (18%). Esophagitis was common during combined modality therapy (grade 3, 10 patients; grade 4 five patients). Forty-two percent of patients had partial response after two courses of induction therapy, and 82% of patients had an objective response at completion of therapy. Twelve patients (36%) had a complete response. Nineteen patients remain progression-free at a median of 8 months; the median survival time has not been reached.

CONCLUSION

This paclitaxel-containing combined modality therapy is feasible and highly active in patients with inoperable stage III lung cancer. Esophagitis is the most common severe toxicity with this program. Further studies with paclitaxel-containing combination regimens in patients with stage III non-small-cell lung cancer are indicated.

Marfan syndrome

Images

Structure of the forewing stretch receptor axon in immature and mature adult locusts

During the first 2 weeks following imaginal ecdysis, the wingbeat frequency of Locusta migratoria doubles, and the activity of the forewing stretch receptor (fSR), in response to wing elevation, increases. We examined the three-dimensional structure of the centrally projecting axon of the fSR during adult maturation to determine if there are changes in the branching geometry. We found that changes occur in the mesothoracic projection (IISR Meso). Here, there was a significant increase in the volume of the projection from 2.3 x 10(4) +/- 0.2 x 10(4) microns 3 in immature locusts to 6.0 x 10(4) +/- 1.2 x 10(4) microns 3 in mature locusts. There were also significant increases in the total length, the number of branch points, the number of axonal swellings, and the diameters of first- and second-order branches of the projection. No significant changes were observed in the prothoracic projection (IISR Pro), and the only significant change observed in IISR Meta was negative allometric growth relative to IISR Meso. These results demonstrate that during adult maturation, growth of the fSR axon is heteromorphic between different ganglionic projections and that there is a potential increase in the connectivity of IISR Meso to other flight neurons in the mesothoracic ganglion. We suggest that this may be a mechanism for maintaining the efficacy of afferent input to flight interneurons that are also growing during maturation.