Using extended reality (XR) for medical training and real-time clinical support during deep space missions

Medical events can affect space crew health and compromise the success of deep space missions. To successfully manage such events, crew members must be sufficiently prepared to manage certain medical conditions for which they are not technically trained. Extended Reality (XR) can provide an immersive, realistic user experience that, when integrated with augmented clinical tools (ACT), can improve training outcomes and provide real-time guidance during non-routine tasks, diagnostic, and therapeutic procedures. The goal of this study was to develop a framework to guide XR platform development using astronaut medical training and guidance as the domain for illustration. We conducted a mixed-methods study-using video conference meetings (45 subject-matter experts), Delphi panel surveys, and a web-based card sorting application-to develop a standard taxonomy of essential XR capabilities. We augmented this by identifying additional models and taxonomies from related fields. Together, this "taxonomy of taxonomies," and the essential XR capabilities identified, serve as an initial framework to structure the development of XR-based medical training and guidance for use during deep space exploration missions. We provide a schematic approach, illustrated with a use case, for how this framework and materials generated through this study might be employed.

Lung metastases treated with image-guided stereotactic body radiation therapy

AIMS

To evaluate outcomes after treatment with image-guided stereotactic body radiation therapy (SBRT) using daily online cone beam computed tomography for malignancies metastatic to the lung.

MATERIALS AND METHODS

Forty-seven lung metastases in 32 patients were treated with volumetrically guided SBRT. The median age was 62 years (21-87). Primaries included colorectal (n = 10), sarcoma (n = 4), head and neck (n = 4), melanoma (n = 3), bladder (n = 2), non-small cell lung cancer (n = 2), renal cell (n = 2), thymoma (n = 2), thyroid (n = 1), endometrial (n = 1) and oesophageal (n = 1). The number of lung metastases per patient ranged from one to three (68% single lesions). SBRT was prescribed to the edge of the target volume to a median dose of 60 Gy (48-65 Gy) in a median of four fractions (four to 10). Most lesions were treated using 12 Gy fractions (92%) to 48 or 60 Gy.

RESULTS

The median follow-up was 27.6 months (7.6-57.1 months). The 1, 2 and 3 year actuarial local control rates for all treated lesions were 97, 92 and 85%, respectively. Two patients with colorectal primaries (four lesions in total) had local failure. The median overall survival was 40 months. The 1, 2 and 3 year overall survival from the time of SBRT completion was 83, 76 and 63%, respectively. There were no grade 4 or 5 toxicities. Grade 3 toxicities (one instance of each) included pneumonitis, dyspnoea, cough, rib fracture and pain.

CONCLUSION

SBRT with daily online cone beam computed tomography for lung metastases achieved excellent local tumour control with low toxicity and encouraging 2 and 3 year survival.

Non-Linear Optical Characteristics of Novel Porphyrin Dye Media

Measurements of sensitive RSA phenonema in new porphyrin dyes are presented. Both the linear and non-linear optical properties are shown to depend strongly on the molecular structure. A detailed analysis of two of the porphyrins reveals that inter-systems crossing rate and the excited state absorption profile are strongly influenced by substitution of a heavy atom into the central atom position. It is shown that by appropriate choice of wavelength values in excess of 30 can be achieved for the material parameter σex / σgr. This value compares well with previously reported results and is achieved in conjunction with excited state lifetimes on the order of 300 ns.

Nondepleting anti-CD40-based therapy prolongs allograft survival in nonhuman primates

Costimulation blockade of the CD40/CD154 pathway has been effective at preventing allograft rejection in numerous transplantation models. This strategy has largely depended on mAbs directed against CD154, limiting the potential for translation due to its association with thromboembolic events. Though targeting CD40 as an alternative to CD154 has been successful at preventing allograft rejection in preclinical models, there have been no reports on the effects of CD40-specific agents in human transplant recipients. This delay in clinical translation may in part be explained by the presence of cellular depletion with many CD40-specific mAbs. As such, the optimal biologic properties of CD40-directed immunotherapy remain to be determined. In this report, we have characterized 3A8, a human CD40-specific mAb and evaluated its efficacy in a rhesus macaque model of islet cell transplantation. Despite partially agonistic properties and the inability to block CD40 binding of soluble CD154 (sCD154) in vitro, 3A8-based therapy markedly prolonged islet allograft survival without depleting B cells. Our results indicate that the allograft-protective effects of CD40-directed costimulation blockade do not require sCD154 blockade, complete antagonism or cellular depletion, and serve to support and guide the continued development of CD40-specific agents for clinical translation.

Ecological release in White Sands lizards

Ecological opportunity is any change that allows populations to escape selection from competition and predation. After encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. We identified ecological opportunity and tested for ecological release in three lizard colonists of White Sands, New Mexico (Sceloporus undulatus, Holbrookia maculata, and Aspidoscelis inornata). First, we provide evidence for ecological opportunity by demonstrating reduced species richness and abundance of potential competitors and predators at White Sands relative to nearby dark soils habitats. Second, we characterize ecological release at White Sands by demonstrating density compensation in the three White Sands lizard species and expanded resource use in White Sands S. undulatus. Contrary to predictions from ecological release models, we observed directional trait change but not increased trait variation in S. undulatus. Our results suggest that ecological opportunity and ecological release can be identified in natural populations, especially those that have recently colonized isolated ecosystems.

An evaluation of commercial DNA extraction kits for the isolation of bacterial spore DNA from soil

AIMS

To evaluate six commercial DNA extraction kits for their ability to isolate PCR-quality DNA from Bacillus spores in various soil samples.

METHODS AND RESULTS

Three soils were inoculated with various amounts of Bacillus cereus spores to simulate an outbreak or intentional release of the threat agent Bacillus anthracis. DNA was isolated from soil samples using six commercial DNA extraction kits. Extraction and purification efficiencies were assessed using a duplex real-time PCR assay that included an internal positive control. The FastDNA(®) SPIN kit for Soil showed the highest DNA extraction yield, while the E.Z.N.A.(®) Soil DNA and PowerSoil(®) DNA Isolation kits showed the highest efficiencies in removing PCR inhibitors from loam soil extracts.

CONCLUSIONS

The results of this study suggest that commercially available extraction kits can be used to extract PCR-quality DNA from bacterial spores in soil. The selection of an appropriate extraction kit should depend on the characteristics of the soil sample and the intended downstream application.

SIGNIFICANCE AND IMPACT OF THE STUDY

  The results of this study aid in the selection of an appropriate DNA extraction kit for a given soil sample. Its application could expedite sample processing for real-time PCR detection of a pathogen in soil.

Porphyrin Dye Media for Optical Limiting

In this report we study nine structurally similar porphyrins and show how the material parameters that control the optical limiting depend on the molecular structure. Optical limiting measurements at 532 nm on the metal-free, zinc and lead analogues of tetraphenyl porphyrin (TPP), tetra(trimethylsilyethynyl) porphyrin (TTMSAP) and tetra(4-n-butylphenylethynyl) porphyrin (TNBBAP) reveal a strong dependence on the molecular structure. A double pump/cw probe technique is used to measure the material parameters that control the optical limiting and the results give a strong insight into how the molecular structure influences the individual parameters. These measurements revealed that one of the materials TTMSAP(Pb) has a σex/σgr ratio of ∼45 at 532 rim, which is one of the largest values ever reported. Finally, broadband measurements with a picosecond white-light source show that the excited state absorption profile for the porphyrins examined is much broader than the ground state features and is centred to the long wavelength side of the ground state Soret band.

Long-term results of full-dose gemcitabine with radiation therapy compared to 5-fluorouracil with radiation therapy for locally advanced pancreatic cancer

287

Background: To retrospectively compare the efficacy and toxicity of full-dose gemcitabine-based chemoradiotherapy (GemRT) vs. 5-fluorouracil (5-FU)-based chemoradiotherapy (5FURT) for locally advanced pancreas cancer (LAPC).

Methods: From January 1998 to December 2008, 93 patients with LAPC were treated either with 5FURT (n=38) or GemRT (n=55). 5FURT consisted of standard-field radiotherapy given concurrently with infusional 5-FU or capecitabine. GemRT consisted of involved-field radiotherapy given concurrently with full-dose gemcitabine (1000 mg/m2 weekly) with or without erlotinib. The follow-up time was calculated from the time of diagnosis to the date of death or last contact.

Results: Eighty-eight of 93 patients have died, and only one was lost to follow-up after developing DM. The median OS was 11.2 months (range 1.5-96). Patient characteristics (including Zubrod score, age, tumor stage, nodal stage, tumor location, and grade) were not significantly different between treatment groups. The OS was significantly better for GemRT compared to 5FURT (median 12.5 months vs. 10.2 months; 51% vs. 34% at 1 year; 12% vs. 0% at 3 years; 7% vs. 0% at 5 years; respectively; p=0.04), although the two groups had same DM (34% at 1 year). GemRT cohort was more likely to receive gemcitabine before or after chemoradiotherapy than 5FURT cohort (85% vs. 37%, p<0.001). Of the subset who received gemcitabine either before or after chemoradiotherapy, OS was still significantly better for GemRT without concurrent erlotinib compared to 5FURT (median 15.1 months vs. 10.7 months; 70% vs. 36% at 1 year; 21% vs. 0% at 3 years; 11% vs. 0% at 5 years; respectively; p=0.005), as was the rate of DM (23% vs. 45%; respectively; p=0.04). The subsequent hospitalization, percent of survival time spend in the hospital, acute and late grade 3-5 gastrointestinal toxicities were not significantly different between the GemRT and 5FURT groups.

Conclusions: Full-dose GemRT was associated with improved OS compared to standard 5FURT. This approach yielded a moderate number of long-term survivors and was not associated with increased hospitalization or severe gastrointestinal toxicity.

No significant financial relationships to disclose.

Potential role of chemoradiotherapy for metastatic pancreatic cancer

344

Background: Patients with metastatic pancreatic cancer have a poor outcome and the radiotherapy is typically only given to patients requiring palliation. We analyzed our institutional pancreas database to compare the outcome between chemotherapy alone vs. chemoradiotherapy.

Methods: From January 2000 to December 2008, 199 metastatic pancreatic cancer patients were retrospectively analyzed. 13 (6.5%) patients received chemoradiotherapy and 186 (93.5%) patients received chemotherapy alone. Chemotherapy regimens consisted of 5-fluorouracil, gemcitabine, erlotinib, or cisplatin. The follow-up time was calculated from the time of diagnosis to the date of death or the last contact. Kaplan-Meier analysis was used to calculate the overall survival (OS).

Results: Median OS was 5.3 months for all patients. Median OS was 4.9 months (0.4–27.0) for patients treated with chemotherapy alone and 7.8 months (0.6–44.1) for those treated with chemoradiotherapy (p = 0.013). Univariate survival analysis of categorical variables for patients treated with chemoradiotherapy revealed that age, race, gender, location of metastatic site, T stage (T3 v. T4) or nodal stage were not significant. However, ECOG performance status (1 v. 2/3) and the dose of radiation (<35 v. >35 Gy) received were associated with improved survival (p = 0.013, p=0.049). Median OS was 12.9 months for ECOG 1 vs. 5.6 months for ECOG 2/3. Median OS was 11.1 months for patients treated with radiotherapy dose > 35 Gy vs. 5.9 months for those who received less than 35 Gy. 3/13 (23%) patients who received chemoradiotherapy lived nearly two years or more.

Conclusions: Metastatic pancreatic cancer patients with good performance score may benefit from chemoradiotherapy. Long-term survival was observed in this selected group.

No significant financial relationships to disclose.

Cardiovascular collapse during ethanol sclerotherapy in a pediatric patient

Ethanol sclerotherapy is a first line management therapy for low flow vascular malformations. It is usually performed under general anesthesia because of the pain associated with ethanol injection. Ethanol sclerotherapy frequently produces minor local complications but may rarely produce catastrophic cardiopulmonary complications. This report describes the cardiovascular collapse associated with an ethanol sclerotherapy procedure in an 11-year- old child. The evidence for ethanol-induced cardiovascular derangements is discussed.

The position and volume of the small bowel during adjuvant radiation therapy for rectal cancer

PURPOSE

The rate of small bowel toxicity from adjuvant pelvic radiation therapy (RT) for rectal cancer has been reported to be lower for patients treated preoperatively (Preop). This was probably due to a lesser volume of irradiated small bowel; however, studies of postoperative treatment reported that patients with an abdominoperineal resection (APR), who likely have the largest volume of small bowel in the pelvis, had less acute and chronic toxicity than those with a low anterior resection (LAR). In this study, three-dimensional treatment planning techniques were used to characterize the position and volume of small bowel in the pelvis and compare these to repeat studies obtained during the typical 5-week course of treatment to attempt to explain the above observations.

METHODS AND MATERIALS

Treatment planning CT scans were obtained in 30 patients with rectal cancer (10 Preop, 10 LAR, 10 APR), including 12 patients with weekly CT scans during RT (65 scans). The position of the small bowel was measured by the distance to the nearest small bowel from the bones of the posterior pelvis and by the volume of small bowel within four anatomically defined regions of the pelvis. The motion of the small bowel was expressed as the standard deviation of the small bowel position measured with both the distance and the volume in the 12 patients with repeat studies.

RESULTS

Contrast-containing small bowel was found an average 2.9 cm more anterior than small bowel without contrast below the sacral promontory. The position of the small bowel in Preop patients was significantly more anterior (p < or = 0.01) with less volume (p < or = 0.04) in the pelvis than postoperatively treated patients. The small bowel was also more anterior for patients with an LAR vs. APR (p < or = 0.03) but with similar volume in all pelvic regions. Small bowel motion, expressed as the standard deviation of the distance from the bones of the posterior pelvis to the closest small bowel, was 2.9 cm, 1.4 cm, and 0.2 cm for the Preop, LAR, and APR group, respectively. The LAR group had a considerable degree of motion in the posterior pelvis. Increased bladder volume was associated with reduced small bowel volumes, although this benefit decreased during treatment.

CONCLUSION

Because treatment planning CT scans can detect small bowel that does not contain contrast, they may be more accurate than the traditional small bowel series. The Preop patients had significantly less pelvic small bowel supporting the clinical observation of better tolerance to therapy. The higher small bowel toxicity reported for LAR vs. APR patients may be explained by the greater variability of both the position and volume of the small bowel in the posterior pelvis for LAR patients. This finding suggests that a single planning study may not be accurate for the block design used for boost treatment of LAR patients. Bladder-filling techniques were useful for Preop and LAR but not APR patients, and decreased in benefit over time. This study suggested that treatment planning CT scans were more useful than a small bowel series and that more than one treatment planning CT may be obtained in any patient receiving > 45 Gy for rectal cancer. However, further research will be necessary to determine the optimal timing and total number of repeat studies.

Phase I trial of radiation dose escalation with concurrent weekly full-dose gemcitabine in patients with advanced pancreatic cancer

PURPOSE

The primary objective of this phase I trial was to determine the maximum-tolerated dose of radiation that could be delivered to the primary tumor concurrent with full-dose gemcitabine in patients with advanced pancreatic cancer.

PATIENTS AND METHODS

Thirty seven patients with unresectable (n = 34) or incompletely resected pancreatic cancer (n = 3) were treated. Gemcitabine was administered as a 30-minute intravenous infusion at a dose of 1,000 mg/m(2) on days 1, 8, and 15 of a 28-day cycle. Radiation therapy was initiated on day 1 and directed at the primary tumor alone, without prophylactic nodal coverage. The starting radiation dose was 24 Gy in 1.6-Gy fractions. Escalation was achieved by increasing the fraction size in increments of 0.2 Gy, keeping the duration of radiation constant at 3 weeks. A second cycle of gemcitabine alone was intended after a 1-week rest.

RESULTS

Two of six assessable patients experienced dose-limiting toxicity at the final planned dose level of the trial (42 Gy in 2.8-Gy fractions), one with grade 4 vomiting and one with gastric/duodenal ulceration. Two additional patients at this dose level experienced late gastrointestinal toxicity that required surgical management.

CONCLUSION

The final dose investigated (42 Gy) is not recommended for further study considering the occurrence of both acute and late toxicity. However, a phase II trial of this novel gemcitabine-based chemoradiotherapy approach, at a radiation dose of 36 Gy in 2.4-Gy fractions, is recommended on the basis of tolerance, patterns of failure, and survival data.

Annular abscesses in surgical endocarditis: anatomic, clinical, and operative features

BACKGROUND

The aim of this study was to determine patterns of anatomic, clinical, and operative features in surgical endocarditis (SE) with annular abscess (AA).

METHODS

The study consisted of a retrospective analysis of SE cases with AA between 1981 and 1997.

RESULTS

A total of 41 cases with AA were found in 106 consecutive SE cases. There was a higher incidence of AA in aortic (37 of 71 [52%]) (p<0.01) compared to mitral (6 of 42 [14.3%]) or tricuspid (0 of 12) infections. However, the mitral abscesses had a greater tendency toward fistula or pseudoaneurysm formation (4 of 6 [67%]) than other valve abscess cavities (7 of 46 [15%]) (p<0.01). Severe heart failure (p<0.01), heart block (p<0.05), and fistula/pseudoaneurysm (p<0.001), were more often found in SE with AA than without. There were 46 separate aortic AA in 37 instances of aortic valve SE. Of these, 31 of 46 (67%) were less than 1 cm (group 1), 10 of 46 (22%) were large but confined to a given cusp annulus (group 2), 4 of 46 (8.6%) were large between multiple cusps (group 3), and 1 of 46 (2.2%) was circumferential (group 4). There were four instances of aortoventricular discontinuity. Group 1 abscesses were repaired by local closure without a patch significantly more often than the other groups. The mortality of SE with AA was significantly greater for larger AA (groups 3 and 4, 3 of 5 [60%]) than for smaller AA (groups 1 and 2, 0 of 36) (p<0.001). There were six separate mitral AA in six instances of mitral SE, five requiring patch repair. The 30-day operative mortality for AA cases was 3 of 41 (7.3%) compared to 2 of 65 (3.1%) without AA. All AA mortalities involved large AA in the aortic valve position. Of 35 mechanical valves placed for AA, only one required subsequent removal for prosthetic endocarditis.

CONCLUSIONS

Annular abscesses are most frequent in aortic AA, but fistulas/pseudoaneurysms are more frequent in mitral AA. Small to moderate aortic AA can be managed by local closure without an increased mortality compared to SE without AA. Patients with large aortic AA have a higher operative mortality. Mechanical prostheses are safe and effective for the majority of patients with AA.

Pain factors associated with physical disability in a sample of community-dwelling senior citizens

BACKGROUND

Little is known about the specific aspects of pain that may contribute to the association between pain and disability. This study investigated whether the presence of a physical disability is associated with specific aspects of musculoskeletal pain.

METHODS

Questionnaires sent to a sample of community-dwelling seniors included detailed questions about pain; the topics covered pain intensity, frequency, duration and location, use of pain medication, cause of pain, physical disability, depressive symptoms, chronic conditions, and demographic information.

RESULTS

Of the 885 respondents, 644 reported musculoskeletal pain (mean age = 75.85 years, SD = 5.83; 63.2% men vs 36.8% women). Multiple logistic regression analysis revealed that pain of severe or greater intensity was shown to be significantly associated with disability (odds ratio [OR] = 4.32, 95% confidence interval [CI] 2.01 and 9.01, respectively). Pain experienced all or nearly all of the time (OR = 2.00, 95% CI 1.07 and 3.72) and taking pain medication (OR = 1.64, 95% CI 1.08 and 2.5 1) were also shown to be associated with disability. The number of pain locations reported by the respondents was also shown to be significantly associated with disability. The OR for the mean number of pain locations (5.8 locations out of a possible 45) was calculated to be 2.12 (95% CI 1.43 and 3.16).

CONCLUSION

A thorough pain evaluation and appropriate management of certain aspects of pain may aid in the independent functioning of elderly persons.

DO11.10 and OT-II T cells recognize a C-terminal ovalbumin 323-339 epitope

The OVA323-339 epitope recognized by DO11.10 (H-2d) and OT-II (H-2b) T cells was investigated using amino- and carboxy-terminal truncations to locate the approximate ends of the epitopes and single amino acid substitutions of OVA323-339 to identify critical TCR contact residues of the OVA323-339 peptide. DO11.10 and OT-II T cells are both specific for a C-terminal epitope whose core encompasses amino acids 329-337. Amino acid 333 was identified as the primary TCR contact residue for both cells, and amino acid 331 was found to be an important secondary TCR contact residue; however, the importance of other secondary TCR contact residues and peptide flanking residues differ between the cells. Additional OVA323-339-specific clones were generated that recognized epitopes found in the N-terminal end or in the center of the peptide. These findings indicate that OVA323-339 can be presented by I-Ad in at least three binding registers. This study highlights some of the complexities of peptide Ags such as OVA323-339, which contain a nested set of overlapping T cell epitopes and MHC binding registers.

The value of patient feedback in the audit of TMJ arthroscopy

AIM

This study assessed the patients' and clinicians' perception of the outcome of temporomandibular joint arthroscopy.

METHOD

All patients who underwent TMJ arthroscopy for both diagnostic and therapeutic purposes over a 6-year period were sent a questionnaire that asked about various symptoms attributable to the TMJ. Additionally a review of the clinical notes was performed.

RESULTS

83 patients underwent arthroscopy to 127 temporomandibular joints. The mean follow up was 3.6 years. 55% of patients assessed their jaw function as being effective, jaw movement, pain control, and overall satisfaction were satisfactory in 37%, 57%, and 48% of cases respectively. The clinicians' assessment revealed that 45% of patients had no joint tenderness, 74% of patients were able to open to > 35 mm and 74% of patients were free of any joint noise. 66% of patients were prepared to undergo a second procedure if indicated.

CONCLUSION

Overall, 50% of patients seemed to view arthroscopy favourably although many patients still felt that jaw opening was restricted. The outcome was not related to the position and reducibility of the disc at surgery and other variables may be responsible. The disparity between the clinical evaluation and the patients' perception of effectiveness emphasises the importance of patient feedback.

The effect of radiation on an ambulatory chemotherapy infusion pump

BACKGROUND

Ambulatory infusion pumps are used to deliver concurrent chemotherapy with pelvic radiation therapy for patients with rectal carcinoma. The pump is worn around the waist and may be exposed to direct as well as scattered radiation, possibly leading to a complete malfunction, requiring a new pump, and/or changes in the pump timing, with clinically significant reductions in chemotherapy administration.

METHODS

Two new ambulatory chemotherapy pumps were irradiated using a 6-megavolt linear accelerator. The first pump received gradually increasing doses to determine whether a complete malfunction were possible and the approximate dose. The second pump was irradiated with a single large dose of 20 Gray (Gy) followed by smaller doses of 2 Gy to characterize the dose better. After each dose of radiation was given to both pumps, an internal self-diagnostic test and an independent assessment of the pump timing were performed.

RESULTS

The first pump malfunctioned completely at a cumulative dose of 38.6 Gy after receiving an individual dose of 20 Gy. The second pump tolerated the single dose of 20 Gy without difficulty and completely malfunctioned at doses of 40-42 Gy. The second pump exhibited a reduction in pump timing by 25% at a cumulative dose of 40 Gy, which resolved spontaneously by approximately 2 hours.

CONCLUSIONS

Even if removed from the direct radiation beam, an individual pump could accumulate enough radiation for complete failure during the treatment of fewer than 20 patients. Prior to a complete malfunction, the flow rate of chemotherapy may decrease by 25% for a number of hours without detection. Additional work will be necessary to define further the nature of the reduction in pump timing observed.

Cutting edge: dueling TCRs: peptide antagonism of CD4+ T cells with dual antigen specificities

T cells expressing two different TCRs were generated by interbreeding 3A9 and AND CD4+ TCR transgenic mice specific for the hen egg lysozyme (HEL) peptide 48-62:I-Ak and moth cytochrome c (MCC) peptide 88-103:I-Ek peptide:MHC ligands, respectively. Peripheral T cells in the offspring express two TCR V beta-chains and respond to HEL and MCC. We observed minimal or no additive effects upon simultaneous suboptimal stimulation with both agonist peptides; however, an antagonist peptide for the 3A9 TCR was able to inhibit the response of the dual receptor T cells to MCC, the AND TCR agonist. This HEL antagonist peptide did not affect AND single transgenic T cells, indicating that the antagonism observed in the dual TCR cells is dependent on the presence of the HEL-specific 3A9 TCR. In contrast, anti-TCR Abs mediate receptor-specific antagonism. These results demonstrate that peptide antagonism exerts a dominant effect.

The use of active breathing control (ABC) to reduce margin for breathing motion

PURPOSE

For tumors in the thorax and abdomen, reducing the treatment margin for organ motion due to breathing reduces the volume of normal tissues that will be irradiated. A higher dose can be delivered to the target, provided that the risk of marginal misses is not increased. To ensure safe margin reduction, we investigated the feasibility of using active breathing control (ABC) to temporarily immobilize the patient's breathing. Treatment planning and delivery can then be performed at identical ABC conditions with minimal margin for breathing motion.

METHODS AND MATERIALS

An ABC apparatus is constructed consisting of 2 pairs of flow monitor and scissor valve, 1 each to control the inspiration and expiration paths to the patient. The patient breathes through a mouth-piece connected to the ABC apparatus. The respiratory signal is processed continuously, using a personal computer that displays the changing lung volume in real-time. After the patient's breathing pattern becomes stable, the operator activates ABC at a preselected phase in the breathing cycle. Both valves are then closed to immobilize breathing motion. Breathing motion of 12 patients were held with ABC to examine their acceptance of the procedure. The feasibility of applying ABC for treatment was tested in 5 patients by acquiring volumetric scans with a spiral computed tomography (CT) scanner during active breath-hold. Two patients had Hodgkin's disease, 2 had metastatic liver cancer, and 1 had lung cancer. Two intrafraction ABC scans were acquired at the same respiratory phase near the end of normal or deep inspiration. An additional ABC scan near the end of normal expiration was acquired for 2 patients. The ABC scans were also repeated 1 week later for a Hodgkin's patient. In 1 liver patient, ABC scans were acquired at 7 different phases of the breathing cycle to facilitate examination of the liver motion associated with ventilation. Contours of the lungs and livers were outlined when applicable. The variation of the organ positions and volumes for the different scans were quantified and compared.

RESULTS

The ABC procedure was well tolerated in the 12 patients. When ABC was applied near the end of normal expiration, the minimal duration of active breath-hold was 15 s for 1 patient with lung cancer, and 20 s or more for all other patients. The duration was greater than 40 s for 2 patients with Hodgkin's disease when ABC was applied during deep inspiration. Scan artifacts associated with normal breathing motion were not observed in the ABC scans. The analysis of the small set of intrafraction scan data indicated that with ABC, the liver volumes were reproducible at about 1%, and lung volumes to within 6 %. The excursions of a "center of target" parameter for the livers were less than 1 mm at the same respiratory phase, but were larger than 4 mm at the extremes of the breathing cycle. The inter-fraction scan study indicated that daily setup variation contributed to the uncertainty in assessing the reproducibility of organ immobilization with ABC between treatment fractions.

CONCLUSION

The results were encouraging; ABC provides a simple means to minimize breathing motion. When applied for CT scanning and treatment, the ABC procedure requires no more than standard operation of the CT scanner or the medical accelerator. The ABC scans are void of motion artifacts commonly seen on fast spiral CT scans. When acquired at different points in the breathing cycle, these ABC scans show organ motion in three-dimension (3D) that can be used to enhance treatment planning. Reproducibility of organ immobilization with ABC throughout the course of treatment must be quantified before the procedure can be applied to reduce margin for conformal treatment.

Domains of social communication handicap in autism spectrum disorder

OBJECTIVE

To investigate whether specific "social communication" handicaps could be identified in autism spectrum disorder using the Autism Diagnostic Observation Schedule and to compare the results with those found in a previous factor-analysis study using the Autism Diagnostic Interview-Revised.

METHOD

All subjects were evaluated with both instruments. J.R. and P.E.T. independently diagnosed autism, Asperger's disorder, or pervasive developmental disorder--not otherwise specified in 51 children. Items from the Autism Diagnostic Observation Schedule that represented social communication behaviors were factor-analyzed.

RESULTS

Three factors were identified: joint attention, affective reciprocity, and theory of mind. These are the same social communication domains that were identified in the previous study.

CONCLUSIONS

These 3 social communication domains have been discussed in the literature regarding normal development and in previous research on autism spectrum disorders. If these domains are replicated in larger sample sizes, they could be used to monitor the results of pharmacological and psychotherapeutic interventions in autism spectrum disorders.

Bromodeoxyuridine alternating with radiation for advanced uterine cervix cancer: a phase I and drug incorporation study

PURPOSE

Preclinical studies show a significant increase in the ratio of the radiosensitizer bromodeoxyuridine (BUdR) in tumors versus the intestinal mucosa during the drug elimination period, compared with the ratio during drug infusion. We constructed a phase I study in patients with locally advanced cervix cancer, using alternating cycles of BUdR and radiation therapy (RT).

PATIENTS AND METHODS

Eighteen patients with stage IIB to IVA cervix cancer participated. A treatment cycle consisted of a 4-day BUdR infusion followed by a week of pelvic RT, 15 Gy twice daily in 1.5-Gy fractions. After three cycles, additional BUdR was infused, followed by brachytherapy. The fraction of thymidine replaced by BUdR and the fraction of cells incorporating BUdR were determined in rectal mucosa and tumor biopsies at the end of the first BUdR infusion (day 5), at the middle of the first RT week (day 10), and at the time of brachytherapy.

RESULTS

Dose-limiting toxicity was observed in one of 16 patients receiving 1,000 mg/m2/d x 4 days and in both patients receiving 1,333 mg/m2/d x 4 days each cycle. After a median follow-up of 39 months, 12 patients (66%) were free of pelvic disease and nine (50%) were alive and disease free. The ratio of tumor to rectum BUdR incorporation averaged 1.5 to 1.8 and did not differ significantly between day 5 and day 10. A trend toward reduced ratio was observed at brachytherapy. Drug-containing cells in rectal biopsies migrated from the crypts to the mucosal surface.

CONCLUSION

In this schedule, 1,000 mg/m2/d is the maximum-tolerated dose of BUdR. BUdR incorporation levels in tumors were consistent with clinically significant radiosensitization. The migration of BUdR-containing rectal mucosa cells from the crypts to the surface at the time of RT suggests that this regimen may offer a relative sparing of the mucosa from radiosensitization.

Characteristics of toddlers and preschoolers exhibiting severe psychiatric disturbance

The present study reports data collected on 137 toddler and preschool children admitted for acute, psychiatric inpatient hospitalization. Utilizing a comprehensive chart review survey developed by the authors, information was obtained regarding presenting problems, family psychiatric history, family legal problems, child maltreatment in order to examine factors contributing to the need for psychiatric hospitalization. Extremely dangerous behaviors were displayed by these youngsters, placing themselves and others at significant risk of harm. The frequency of occurrence of factors that contributed to these severe adjustment difficulties was alarming. Implications regarding service needs for these young children are discussed.

Reversible snaring for proper prosthetic seating during valve replacement

A method of reversible suture snaring is described for evaluating the final valve seating and positioning before knot tying of valve sutures. This allows for alteration of the operative plan before investing substantial ischemic time in a nonfunctional result. The procedure has been used in 577 consecutive prosthetic valve replacements in the past 5 years. The technique maintains proper seating while the valve is permanently anchored in place.

Effect of filgrastim (G-CSF) during chemotherapy and abdomino-pelvic radiation therapy in patients with ovarian carcinoma

PURPOSE

To evaluate the safety and effectiveness of filgrastim (granulocyte colony-stimulating factor, G-CSF) in reducing neutropenia and treatment interruptions during whole abdominal radiotherapy for ovarian cancer.

METHODS AND MATERIALS

Sixteen patients with ovarian cancer treated with 2 to 6 courses of cisplatin-containing chemotherapy and abdomino-pelvic radiation therapy received filgrastim for neutrophil counts <2 x 10(9)/L. Endpoints for analysis included the ability to maintain the neutrophil count in the target range, number of treatment interruptions due to neutropenia, and toxicity attributed to filgrastim.

RESULTS

Fourteen patients received a mean of 2.9 courses of filgrastim (each with a mean duration of 4.1 days), with no treatment interruptions due to neutropenia. The majority of neutrophil counts were maintained above the target range of 2 x 10(9)/L during treatment. Thrombocytopenia requiring treatment interruption was seen in six patients and necessitated platelet transfusions in one. Thrombocytopenia occurred at a mean abdominal radiation dose of 2207 cGy and in all but one patient was preceded by one or more episodes of neutropenia. In comparison with a control group of 31 patients treated without filgrastim there was no reduction in treatment interruptions. Four patients did not complete treatment because of persistent thrombocytopenia yet received a mean of 94% of the planned abdominal radiation dose and 69% of the planned pelvic dose. Filgrastim toxicity was limited to mild skeletal pains in six patients and a Grade 1 skin rash in two patients.

CONCLUSIONS

Filgrastim is safe and effective in preventing neutropenia and reducing neutropenic treatment interruptions during abdominal radiotherapy in patients with ovarian cancer. However, there was no clear benefit to the use of filgrastim as thrombocytopenia became the dose-limiting toxicity resulting in a risk of treatment interruptions and early termination of radiotherapy.

Customized gynecologic interstitial implants: CT-based planning, dose evaluation, and optimization aided by laparotomy

PURPOSE

Interstitial perineal implants may be utilized to deliver a high local radiation dose in the treatment of advanced gynecologic malignancies. Lack of knowledge of the precise anatomic relationships between the implant and the target and critical organs may limit efficacy and increase complication risks. Computed tomography (CT)-based planning, dose evaluation, and optimization of customized interstitial implants, aided by laparotomy, have been developed to overcome these limitations.

METHODS AND MATERIALS

Twenty patients with locally advanced gynecologic malignancies treated between May 1990 to October 1996 with external irradiation and one or two implants. Interstitial implants were performed when intracavitary brachytherapy was judged to be inadequate or when the response to external radiation and an intracavitary implant was not satisfactory. Customized interstitial implants were planned using preimplantation CT to determine catheter angles and paths that best implanted the target while avoiding pelvic bones and organs. Laparotomy aimed at lysing bowel adhesions, placement of omental carpet, and refining needle placement. Postimplantation CT was used for loading optimization and dose evaluation.

RESULTS

Catheter angles 15-25 degrees were found to adequately implant anteriorly laying targets while avoiding pubic bones and bladder. Adhesiolysis of bowel loops from the vaginal apex was required in patients with prior hysterectomy. Small modifications in catheter placements were made during laparotomy in all implants. Postimplantation CTs showed deviations of the catheter positions compared with the planning CTs and were essential in determining target and organ doses and loading optimization. At a median follow-up of 42 months (range: 9-80 months), local control rate is 55% and disease-free survival 40%. Late complications occurred in 2 of 11 of patients without local recurrence.

CONCLUSIONS

CT-based planning, loading optimization, and dose evaluation of customized implants improve radiation dose delivery. Laparotomy enhances implant accuracy and safety. Local tumor control rate is still unsatisfactory. It reflects the shortcomings of technical advances alone in poor prognosis tumors like those selected for this series.

Preoperative idoxuridine and radiation for large soft tissue sarcomas: clinical results with five-year follow-up

BACKGROUND

Local control remains an important issue in the management of large soft tissue sarcomas. Radiation is the main adjuvant to surgery for local therapy of sarcomas, but it requires relatively high doses, hitherto considered prohibitive in areas such as the retroperitoneum. We developed a preoperative treatment approach to large soft tissue sarcomas that would deliver a high total dose of radiation administered in conjunction with the halogenated pyrimidine radiosensitizer idoxuridine (IdUrd).

METHODS

Thirty-seven patients with large sarcomas of the head and neck, mediastinum, retroperitoneum, or extremity received three or five cycles of sequential IdUrd infusion (1000-1600 mg/m2/d x 5 d) alternating weekly with twice daily radiation (125-150 cGy per dose) and were then evaluated for resection. The delivered preoperative radiation dose was up to 6250 to 7500 cGy.

RESULTS

Five patients (14%) had a partial response to preoperative therapy, and 28 of 37 patients underwent successful resection. There were no intra- or postoperative deaths. Local control was achieved in 19 of 28 resected patients, but in only 1 of 6 patients who remained unresectable despite therapy. With a median follow-up of 5.8 years, 28% of patients are alive with no evidence of disease, 17% are alive with disease, and 53% have died of their disease.

CONCLUSIONS

Using the dose and schedule we employed, resection of large soft tissue sarcomas was possible after high-dose radiation delivered in conjunction with IdUrd. Although local control was acceptable, the high rate of distant failure represents a limitation of any local approach to the treatment of large soft tissue sarcomas and suggests the need for integration of this approach with an effective systemic therapy.

High-precision genotyping by denaturing capillary electrophoresis

Genotyping, as applied to linkage mapping, human identification, or mapping of genetic traits, mandates electrophoretic separation systems that enable a user to identify alleles with high precision to obtain a correct genotype. For 2-bp microsatellites or short tandem repeats (STRs), standard deviations of +/-0.3 nucleotide are required to ensure with 99.7% probability the identity or dissimilarity of tested alleles. A complete system, consisting of commercially available laser-induced fluorescence capillary electrophoresis (ABI PRISM 310) and performance optimized polymer 4 (POP-4), was evaluated for microsatellite separations. POP-4 is a low viscosity polymer for use in uncoated fused microbore silica capillaries. It separates DNA fragments that differ in size by 1 nucleotide up to 250 nucleotides and that differ in size by 2 nucleotides for fragments up to at least 350 nucleotides in length in about 30 min. The presence of denaturants and, more importantly, operation at 60 degrees C was mandatory for high-precision and high-resolution sizing operation. Reproducible separation performance was achieved in excess of 100 injections per capillary with resulting standard deviations in the range of 0.04 to 0.17 nucleotide. Comparative sizing of known CEPH (Centre d'Etudes du Polymorphisme Humaine) samples performed at 22 independent test sites showed the usefulness of the system for genotyping with standard deviations of 0.24 nucleotide, or better.

Analysis of multiplexed short tandem repeat (STR) systems using capillary array electrophoresis

The profiling of polymorphic short tandem repeat (STR) markers is being applied to human identification, parentage testing and genetic mapping. Reliable genotyping of these markers is facilitated by polymerase chain reaction (PCR) amplification and high-resolution electrophoretic separation. Capillary array electrophoresis (CAE) offers very rapid, high-resolution separation of the amplified DNA and potential for automated sample processing not realized employing conventional slab-gel electrophoresis. The use of CAE to type DNA samples amplified at 11 genetic loci in multiplex profiles is presented. Two sets totaling 208 samples were amplified in a multiplex fashion using AmpFlSTR-Blue or AmpFlSTR-Green I and analyzed in a blind study using CAE. With the exception of one sample, the CAE genotyping results were in complete agreement with results obtained using a single-capillary system or two slab-gel electrophoresis systems. The sample, genotype TH01 7/10, migrated similar to TH01 6.3/9.3 allele sizes, which suggested a potential band migration shift. The recommended approach to such an observation is to analyze the sample again. The sample was rerun and correct genotype verified. Allelic ladder samples were analyzed multiple times by CAE to determine sizing accuracy and precision. The sizing of over 240 allelic ladder samples yielded an average within-run precision of +/- 0.13 bp and between-run precision of +/- 0.21 bp for fragments up to 350 bp. The CAE protocols permit processing of up to 96 multiplex STR samples in under 70 min.

A phase I trial of hepatic arterial bromodeoxyuridine and conformal radiation therapy for patients with primary hepatobiliary cancers or colorectal liver metastases

PURPOSE

We have previously found that conformal radiation therapy (RT) and hepatic arterial fluorodeoxyuridine was associated with durable responses and long-term survival for patients treated for nondiffuse primary hepatobiliary tumors and colorectal liver metastases. Further improvements in hepatic control may result from the addition of selective radiosensitization using bromodeoxyuridine (BrdU) infused through the hepatic artery (HA) concurrently with RT. This is a Phase I study of escalating doses of HA BrdU combined with our standard hepatic RT.

METHODS AND MATERIALS

Patients with unresectable primary hepatobiliary cancer or colorectal liver metastases were treated with concurrent HA BrdU and conformal RT (1.5 Gy per fraction, twice a day). Three-dimensional treatment planning was used to define both the target and normal liver volumes. The total dose of RT (24, 48, or 66 Gy) was determined by the fractional volume of normal liver excluded from the high dose volume. HA BrdU was escalated in standard Phase I fashion with at least three patients receiving each combination of RT dose and BrdU dose. The starting dose of HA BrdU was 10 mg/kg/day, with two potential escalations to a maximum of 25 mg/kg/day (the maximum tolerable dose of HA BrdU when given alone on this same schedule). Grade > or = 3 toxicity was considered dose limiting. Patients receiving 24 Gy had one cycle of HA BrdU, while those receiving either 48 or 66 Gy had two cycles. Patients were followed for toxicity, complications, and response (when evaluable).

RESULTS

A total of 41 patients (18 with colorectal liver metastases, 16 with cholangiocarcinoma and 7 with hepatoma) were treated. Five patients were removed from the protocol (three had HA catheter complications, one developed atrial fibrillation, and one was removed due to recurrent Grade 4 toxicity), although all five are included for toxicity purposes. Dose-limiting toxicity was primarily thrombocytopenia and there was no obvious relationship with the RT dose. Only 2 of 17 cycles given at 25 mg/kg/day had Grade > or = 3 toxicity. Complications developed in four patients, including one patient with radiation-induced liver disease. Response rates were not improved compared to our previous experience.

CONCLUSIONS

The appropriate dose of HA BrdU for Phase II evaluation is 25 mg/kg/day. Neither the hepatic parenchyma nor the gastrointestinal mucosa appeared to be sensitized by this method of BrdU administration. It is anticipated that these, or still newer methods of therapy, can improve treatment results in the near future.

Ultrasonic debridement of mitral calcification

Dense annular calcification to the valve attachment is particularly hazardous during mitral valve replacement because of the difficulty of placing sutures and the risk of atrioventricular rupture. We report 11 patients who underwent decalcification of the mitral anulus with the Cavitron Ultrasound Surgical Aspirator (CUSA) during mitral valve replacement. This resulted in a greatly simplified suture placement and prosthetic valve seating as well as enlargement of the annular orifice. Four other patients underwent CUSA debridement of the anterior leaflet of the mitral valve during concomitant aortic valve replacement and CUSA debridement of the aortic anulus. There were no operative deaths or major complications. Ultrasonic debridement is a useful adjunct in the surgical management of the heavily calcified mitral valve.

Potential benefits of eliminating planning target volume expansions for patient breathing in the treatment of liver tumors

PURPOSE

To investigate potential benefits derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through examination of hepatic tumors treated with conformal therapy.

METHODS AND MATERIALS

We reviewed the treatment plans of 50 patients who had previously received conformal partial organ liver irradiation for treatment of hepatic malignancies. PTVs for these plans included expansions (1-2 cm) for patient breathing. Data consisted of the three-dimensional dose distributions computed for the conformal plans generated for these volumes, and also for plans using identical beam arrangements but smaller block margins to treat planning target volumes that did not include the expansions for breathing. We calculated effective volumes (V(eff)) and normal tissue complication probabilities (NTCP) using dose-volume histograms for normal liver and analyzed changes in: V(eff), NTCP at the prescription dose, doses associated with selected NTCP levels, and tumor control probabilities (TCP) at these new dose levels.

RESULTS

Elimination of the patient breathing components of the PTVs for these conformal treatments of liver tumors: (a) decreased the average V(eff) by 5%; (b) decreased the average predicted NTCP at the prescription (isocenter) dose used to treat the patients by 4.5%; (c) increased the average target volume (isocenter) dose associated with low (1-10%) predicted normal liver NTCP by 6-8 Gy, which corresponded to (d) a predicted average 6-7% increase in TCP for aggressive liver tumors. Plans with PTV expansions for breathing that occurred mostly within the liver showed greatest potential benefit.

CONCLUSIONS

Elimination of the margin added to hepatic target volumes for patient ventilation could lead to clinically meaningful increases in dose without increasing the predicted frequency of complications.

Case study: the use of melatonin in a boy with refractory bipolar disorder

The authors describe the clinical course of a 10-year-old boy with bipolar disorder diagnosed at age 5 years. Lithium, carbamazepine, and valproic acid were ineffective or caused intolerable side effects. A trial of melatonin led to rapid relief of insomnia and aborted a manic episode. He has continued to take melatonin and adjunctive alprazolam for 15 months without recurrence of insomnia or mania. Affective disorders involving circadian dysregulation may respond to interventions that restore a normal sleep-wake cycle. Literature supporting this hypothesis is cited.

Defining microsatellite alleles by genotyping global indigenous human populations and non-human primates

Polymorphisms at variable number of tandem repeat (VNTR) loci have been used in forensic science for almost decade. Microsatellite loci, especially tri-, tetra-, and pentanucleotide repeat loci, have shown great potential in personal identification and paternity testing. In this report, we describe results of genotyping three tetranucleotide repeat loci (D5S818, D7S820, D13S317) in 16 worldwide indigenous human populations and one chimpanzee population which were being developed for forensic applications. We demonstrate the utility of typing globally diverse populations in defining microsatellite alleles: Specifically (i) investigating the measurement errors of each allele using semi-automatic genotyping instrumentation and software, (ii) assessing the range of alleles, (iii) understanding the extent of allele frequency differences across worldwide populations, and (iv) identifying possible anomalous alleles with complex structures.