Investigation of the conjectured nucleon deformation at low momentum transfer

We report new precise H(e,e(')p)pi(0) measurements at the Delta(1232) resonance at Q(2)=0.127 (GeV/c)(2) obtained at the MIT-Bates out-of-plane scattering facility which are particularly sensitive to the transverse electric amplitude (E2) of the gamma(*)N-->Delta transition. The new data have been analyzed together with those of earlier measurements to yield precise quadrupole to dipole amplitude ratios: Re(E(3/2)(1+)/M(3/2)(1+))=(-2.3+/-0.3(stat+syst)+/-0.6(model))% and Re(S(3/2)(1+)/M(3/2)(1+))=(-6.1+/-0.2(stat+syst)+/-0.5(model))% for M(3/2)(1+)=(41.4+/-0.3(stat+syst)+/-0.4(model))(10(-3)/m(pi(+))). The derived amplitudes give credence to the conjecture of deformation in hadrons favoring, at low Q2, the dominance of mesonic effects.

Thallium-201 scintigraphy–a predictor of tumour necrosis in soft tissue sarcoma following preoperative radiotherapy?

AIM

Thallium-201 (Tl-201) scintigraphy in patients with malignant soft tissue tumours was evaluated to determine whether the images correlated with histological response to preoperative radiotherapy.

METHODS

We studied 54 patients, median age 32 (range 17-84) years, with non-metastatic, malignant soft tissue tumours diagnosed between 1996 and 2001. Thirty-eight patients had unoperated tumours and 16 patients had previous incomplete excisions. All patients received preoperative radiotherapy followed by surgery. No patient received chemotherapy as part of their initial management. Qualitative analyses of early phase (30 min) and late phase (4 h) Tl-201 scintigraphic images before and after preoperative radiotherapy were compared with the degree of tumour necrosis determined histologically.

RESULTS

In the previously unoperated group, all 38 patients had increased TL-201 uptake in the late phase of scanning prior to radiotherapy suggesting metabolically active tissue. In the previously excised group 11 patients had increased Tl-201 uptake in the late phase of scanning prior to radiotherapy. Following radiotherapy, patients with Tl-201 retention on late phase scans had a lower rate of necrosis than patients with minimal retention, p<0.0001. Following radiotherapy, 28 of 29 patients with minimal uptake on the late phase had 80% or more necrosis, while 24 of 25 patients with increased uptake on the late phase had less than 80% necrosis (p<0.0001). Patients with previously excised tumours who had thallium retention following radiotherapy demonstrated evidence of residual disease at surgery. All patients with incompletely excised tumours who had no thallium retention on late phase scanning after radiotherapy demonstrated no evidence of residual disease at surgery.

CONCLUSION

Thallium scintigraphy is a readily available investigative tool, which when used in conjunction with other imaging modalities in the assessment of primary and incompletely excised malignant soft tissue tumours, may predict histological tumour response to preoperative radiotherapy.

Relativistic effects and two-body currents in (H)((-->)e(')p)n using out-of-plane detection

Measurements of the (2)H((-->)e,e(')p)n reaction were performed with the out-of-plane magnetic spectrometers (OOPS) at the MIT-Bates Linear Accelerator. The longitudinal-transverse, f(LT) and f(')(LT), and the transverse-transverse, f(TT), interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q2 = 0.15 (GeV/c)(2). In comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions and the importance of two-body meson-exchange currents and isobar configurations. We demonstrate that such effects can be disentangled by extracting these responses using the novel out-of-plane technique.

The youngest victims of child maltreatment: what happens to infants in a court sample?

Current data show that infants represent an increasing proportion of cases of child maltreatment. To learn more about how infants fare in the current system and to provide baseline data against which to compare outcomes following recent legislative reforms, this study examined a subsample of infants in a sample of 200 care and protection cases brought before the Boston Juvenile Court in 1994. Child, parent, and case characteristics of infants 0 to 3 months of age (n = 46) were compared with characteristics of older children in the sample. All cases were followed prospectively for 4 years, and data were abstracted from court records. Results revealed that the infants were primarily children of substance abusers who had extensive prior histories of child protective service system involvement. Although the majority of the infants were eventually permanently removed from parental custody and adopted, many experienced time delays and multiple placements before achieving permanent homes.

Seasonal pathogen removal by alternative on-site wastewater treatment systems

Subsurface-flow constructed wetlands, sand filters, and peat filters near Duluth, Minnesota, were studied to determine their seasonal performance for removing pathogens from wastewater. Influent was a high-strength septic tank effluent (mean values of 5-day biochemical oxygen demand, total nitrogen, and total phosphorus were 294, 96, and 15 mg/L, respectively) at the Natural Resources Research Institute's alternative treatment system test facility in northern Minnesota. Each treatment system was inoculated with cultures of Salmonella choleraesuis (serotype typhimurium) for 5 to 7 consecutive days in summer and winter during 1998 to 1999. After the seeding, outflow samples were taken until Salmonella counts were sustained at background levels. The removal of Salmonella was calculated for each system, although the exact removal mechanisms were not determined. During the summer, the wetlands removed 99.6 to 99.999 4% (2.4 to 5.3 log10 reduction) of the culturable Salmonella. The sand filters demonstrated a greater than 7 log10 removal of Salmonella cells, whereas the peat filters were responsible for a greater than 8 log10 loss of cells. Fewer Salomonella cells were removed by all of these systems during the winter, although the pattern of removal was similar to their summer operation. During the winter, the wetlands and sand filters removed greater than 1 log10 of culturable cells, but the peat filters were responsible for a greater than 5 log10 loss of cells. Fecal coliform removal patterns reflected those for Salmonella by treatment systems for summer and winter periods. Based on Salmonella and fecal coliform removal, the peat filters operated most effectively followed by the sand filters and the constructed wetlands.

Phase I trial of concurrent tirapazamine, cisplatin, and radiotherapy in patients with advanced head and neck cancer

PURPOSE

To determine the maximum-tolerated dose of tirapazamine when combined with cisplatin and radiation in patients with T3/4 and/or N2/3 squamous cell carcinoma of the head and neck.

PATIENTS AND METHODS

The starting schedule was conventionally fractionated radiotherapy (70 Gy in 7 weeks) with concomitant cisplatin 75 mg/m2 and tirapazamine 290 mg/m2 (before cisplatin) in weeks 1, 4, and 7 and tirapazamine alone 160 mg/m2 three times a week in weeks 2, 3, 5, and 6. Positron emission tomography scans for tumor hypoxia (18F misonidazole) were performed before and during radiotherapy.

RESULTS

We treated 16 patients with predominantly oropharyngeal primary tumors, including 10 patients with T4 or N3 disease. Febrile neutropenia occurred toward the end of radiotherapy in three out of six patients treated on the initial dose level. Two of these patients also developed grade 4 acute radiation reactions. Another 10 patients were treated with the same doses, but the week 5 and week 6 tirapazamine doses were omitted. This resulted in less neutropenia and only one dose-limiting toxicity (DLT) (febrile neutropenia), and eight out of 10 patients completed treatment without any dose omissions. In these 10 patients, the acute radiation toxicities were not obviously enhanced compared with chemoradiotherapy regimens using concurrent platinum and fluorouracil. 18F misonidazole scans detected hypoxia in 14 of 15 patients at baseline, with only one patient having detectable hypoxia at the end of treatment. With a median follow-up of 2.7 years, the 3-year failure-free survival rate was 69% (SE, 12%), the 3-year local progression-free rate was 88% (SE, 8%), and the 3-year overall survival rate was 69% (SE, 12%).

CONCLUSION

DLT was due unexpectedly to febrile neutropenia, which could be overcome by omitting tirapazamine in weeks 5 and 6. The combination of tirapazamine, cisplatin, and radiotherapy resulted in remarkably good and durable clinical responses in patients with very advanced head and neck cancers. It warrants further investigation.

Synthesis and in vitro evaluation of human FP-receptor selective prostaglandin analogues

The in vitro evaluation of a series of saturated prostaglandins revealed that compounds with omega chain aromatic rings retain nanomolar potency for the human prostaglandin F receptor (hFP receptor), exemplified by compound 8. In contrast, the double bonds are required for activity in the series with an acyclic omega chain as in PGF2alpha.

29. F-18 FDG PET for Suspected or Confirmed Regional Recurrence of Colon Cancer. A Prospective Study of Impact and Outcome

Purpose: Survival of patients (pts) undergoing "curative" treatment for colorectal carcinoma remains poor. Retrospective studies suggest that F-18 FDG PET is more accurate than CT for restaging suspected recurrent disease and favourably impacts management. The aim of this study was to confirm this by prospective analysis.Patient Population and Methods: 102 consecutive patients for whom the referring clinicians had prospectively committed to a treatment plan based on conventional staging investigations and who then underwent F-18 FDG PET scanning were evaluated for management change and outcome. The accuracy of PET results was assessed by surgical findings or clinical follow-up.Results: Overall PET changed management in 66/102 (65%) pts including14 pts changed from observation to active treatment after PET localized disease and 6 pts planned for local therapy to observation after negative PET. Planned surgery was cancelled in 28 pts whereas surgery was initiated in 11 pts. Radiotherapy was prevented in 5 pts, initiated in 11 and the radiation field altered in 5 others. The accuracy of the PET results could be assessed in 63/66 (95%) pts in whom management was changed. Relapse was confirmed in 50/51 pts with a positive PET but disease extent was underestimated in 4 cases. False negative PET results were confirmed in 5 cases.Conclusion: FDG PET has a high and appropriate impact on patient management in patients with suspected recurrent disease. PET can miss small volume disease but the major benefit of PET is to prevent futile attempts at local salvage therapies.

Simple mechanisms organise orientation of escape swimming in embryos and hatchling tadpoles of Xenopus laevis

Many amphibian tadpoles hatch and swim before their inner ears and sense of spatial orientation differentiate. We describe upward and downward swimming responses in hatchling Xenopus laevis tadpoles from stages 32 to 37/38 in which the body rotates about its longitudinal axis. Tadpoles are heavier than water and, if touched while lying on the substratum, they reliably swim upwards, often in a tight spiral. This response has been observed using stroboscopic photography and high-speed video recordings. The sense of the spiral is not fixed for individual tadpoles. In ‘more horizontal swimming’ (i.e. in directions within +/−30 degrees of the horizontal), the tadpoles usually swim belly-down, but this position is not a prerequisite for subsequent upward spiral swimming. Newly hatched tadpoles spend 99 % of their time hanging tail-down from mucus secreted by a cement gland on the head. When suspended in mid-water by a mucus strand, tadpoles from stage 31 to 37/38 tend to swim spirally down when touched on the head and up when touched on the tail. The three-dimensional swimming paths of stage 33/34 tadpoles were plotted using simultaneous video images recorded from the side and from above. Tadpoles spiralled for 70 % of the swimming time, and the probability of spiralling increased to 1 as swim path angles became more vertical. Tadpoles were neutrally buoyant in Percoll/water mixtures at 1.05 g cm(−)(3), in which anaesthetised tadpoles floated belly-down and head-up at 30 degrees. In water, their centre of mass was ventral to the muscles in the yolk mass. A simple mathematical model suggests that the orientation of tadpoles during swimming is governed by the action of two torques, one of which raises the head (i.e. increases the pitch) and the other rotates (rolls) the body. Consequently, tadpoles (i) swim belly-down when the body is approximately horizontal because the body is ballasted by dense yolk, and (ii) swim spirally at more vertical orientations when the ballasting no longer stabilises orientation. Measurements in tethered tadpoles show that dorsal body flexion, which could produce a dorsal pitch torque, is present during swimming and increases with tailbeat frequency. We discuss how much of the tadpole's behaviour can be explained by our mathematical model and suggest that, at this stage of development, oriented swimming responses may depend on simple touch reflexes, the organisation of the muscles and physical features of the body, rather than on vestibular reflexes.

Occupational Exposure in Nuclear Medicine and PET

Purpose: With the increasing use of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for scanning in oncology in our center, a radiation dose survey was performed to determine the impact on staff exposure. Conventional nuclear medicine procedures such as gallium scan, bone scans, and sestamibi cardiac scans are used for comparative purposes.Procedure: Patients were measured using a hand-held radiation monitor (Victoreen 450-P) at various distances and times that replicate typical patient contact scenarios in the Diagnostic Imaging Department.Results: We present our findings from the survey and the implications these have on staff radiation exposure. The data suggest that emerging oncologic techniques such as PET, high dose gallium-67, and high dose Tl-201 do not represent a significantly greater occupational radiation hazard than conventional nuclear medicine procedures.

What progress has been made in meeting the needs of seriously maltreated children? The course of 200 cases through the Boston Juvenile Court

OBJECTIVES

The study examined child, parent, and case characteristics in a sample of 200 cases of serious child maltreatment brought before the Boston Juvenile Court (BJC) on Care and Protection petitions in 1994. Whether recent changes in Massachusetts law have been effective in reducing delays in adjudication and helping children achieve permanent placements more quickly was also examined.

METHOD

Data were abstracted from court records by the research team. The 200 cases were followed prospectively for 4 years. Retrospective data on the families' previous involvement with the protective service system were also abstracted from the records. Data from the 1994 cases were compared to that obtained from a sample of cases brought before the BJC in 1985-1986.

RESULTS

Children permanently removed from parental custody in the 1994 sample required less time post-disposition to achieve permanent placements. However, overall, time frames for the 1994 cases remained remarkably similar to those in 1985-1986: children were in the protective service system an average of 5 years; cases required an average of 1.6 years in court; and half of the children permanently removed from parental custody were still in "temporary" foster care at 4-year follow-up.

CONCLUSIONS

Although some improvements have occurred since 1985-1986, the system still fails to meet the needs of seriously maltreated children to achieve permanent placements promptly. The implications of the findings for system reform are discussed.

Three months of chronic ethanol administration and the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 3 months of chronic ethanol administration (CEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 3 months. Then, rats from both diet groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. Postinjury behavioral measurements revealed that brain injury caused significant spatial learning disability in both diet groups. There were no significant differences in spatial learning ability in the sham or brain-injured animals between the control and ethanol diets. However, a trend towards cognitive impairment in the sham animals and a trend towards reduced deficits in the brain-injured animals were observed in the ethanol diet group. Histologic analysis of injured animals from both diet groups revealed similar extents of ipsilateral cortical and hippocampal CA3 damage. These results, in general, suggest that 3 months of CEAn does not significantly alter the behavioral and morphologic outcome of experimental brain injury.

Is there a relationship between systemic perfusion temperature during coronary artery bypass grafting and extent of intraoperative ischemic central nervous system injury?

OBJECTIVE

This study was designed to compare the volume of cerebral infarction in patients operated on under either hypothermic or tepid/normothermic perfusion for coronary revascularization.

METHODS

A randomized trial with preoperative, postoperative, and late neurologic evaluation was conducted in patients undergoing coronary revascularization having either hypothermic or tepid/normothermic perfusion for coronary revascularization. The goal was to determine whether perfusion temperature correlated with neurologic dysfunction associated with coronary artery bypass.

RESULTS

Twelve intraoperative ischemic strokes occurred during coronary revascularization in a series of 291 patients. Six of these were in the group receiving hypothermic perfusion and 6 in groups receiving the tepid/normothermic perfusion. Measuring the infarct volume documented that 3 of the strokes in each group resulted in minor or small infarcts and 3 in each group were significant, major strokes. The volume of infarction, whether including all 6 patients in each group or only those with major strokes, was no different between the hypothermic and the tepid/normothermic groups.

CONCLUSIONS

In this series of 291 patients randomized to perfusion temperature, we observed no relationship between the size of a cerebral ischemic infarct and the perfusate temperature during coronary revascularization.

CD7 expression distinguishes subsets of CD4(+) T cells with distinct functional properties and ability to support replication of HIV-1

Enrichment of a subset of CD4(+)CD45R0(+)CD7(-) T cells has been observed in HIV-infected individuals. We have investigated the ability of CD7(+) and CD7(-) T cells to support replication of HIV and show that virus replicates preferentially in CD7(+) cells. Several possible mechanisms that may underlie such differences in susceptibility to HIV were studied. Our data demonstrate that mitogen stimulation induces poor expression of CD25 and IL-2 in CD7(-) compared with CD7(+) cells. We also show that uninfected CD7(-) cells are more resistant to mitogen-induced apoptosis than CD7(+) cells. Our data support the view that the CD7(-) subset is inherently resistant to HIV replication and that this is due in part to reduced CD25 expression and IL-2 production.