By Dawn's Early Light: Matutinal Mating and Sex Attractants in a Neotropical Mantid.

Females of the neotropical mantis Acanthops falcata adopt a special posture at dawn which is maintained for about 20 minutes. During the same period, males fly strongly, even in the absence of females. Our studies show that in this posture females are secreting a pheromone that acts as a sex attractant. All sexual activity in this species normally occurs between dawn and sunrise. It can be triggered by any dark-to-light transition, irrespective of real time. This sexual periodicity is probably an antipredator adaptation.

Robinson B: Attack autotomy: a defense against predators.

The response of five species of crabs to simulated predator attack was examined. Two terrestrial species autotomized their chelipeds after the chelae were firmly attached to the predator. Selection for attack autotomy is balanced by selection for retention of the cheliped whenever the cheliped is important in social or maintenance functions.

Dispersal by swarming in a social spider.

Groups of Achaearanea wau (Theridiidae) disperse and found new colonies by means of synchronized emigrations of adult and subadult females. Emigrations involve the construction of silk highways from parent colonies to new web sites, synchronized migrations along the highways, and the establishment of daughter colonies. Emigrations of Achaearanea wau are similar in timing, group composition, and in some behavior components to swarming of social bees and wasps.

Case report of uncontrollable pelvic bleeding--managed by a previously unreported method (QuikClot).

Pelvic haemorrhage can be difficult to control. Several measures including packing, drawing pins, stenting and embolization are available. We present a case where these measures failed to control catastrophic pelvic bleeding while operating in the pelvis to excise a dumbbell tumour involving the right S1 nerve root. Attempted surgical control by a vascular surgeon and radiological control through stenting and embolization failed to control the bleeding. QuikClot is an inert substance and acts as a selective sponge. This product is licensed for external use by the British military. We felt that 'internal' use of Quikclot in this situation might be lifesaving and was applied to the bleeding area, stopping the bleeding immediately.

Limb function following conservation treatment of adult soft tissue sarcoma.

Quality of life and limb function were studied in 54 patients who were disease-free 2 or more years after limb-conserving treatment for soft tissue sarcoma of the leg or pelvic girdle. Tumours of the thigh predominated (25 patients) and the mean tumour size was 9.9 cm. 41 patients had been treated with a combination of surgery and radiotherapy (29 with conventional and 12 with high dose), 12 with surgery alone and one with irradiation and intra-arterial doxorubicin. Only 15 patients had a normal range of movement in all lower limb joints and only 12 had normal power in all muscle groups; tumours of the lower leg were particularly unfavourable in this respect. Gait was normal in 42 patients but 8 required a walking aid and 4 a joint support. 16 had detectable lymphoedema but only 2 needed to wear compression hosiery. 35 patients still experienced pain at some time but only 6 required analgesia. However, when assessed by questionnaire for locomotion, grooming and home/leisure/vocational activities, 37 patients (68%) reported excellent function, and only 2 had moderate impairment. Function loss was most marked in leisure (25 patients) and vocational (8) activities, but was mild in 66% of cases. Multivariate analysis was carried out to determine the prognostic factors for poor limb function. The results suggested that overall functional score was predominantly determined by gait (P less than 0.001), muscle power or range of movement (P less than 0.001), with increasing age, female sex and the use of radiotherapy poor prognostic factors. Reduced muscle power or range of movement were the major factors determining gait (P less than 0.02) with the use of radiotherapy the significant prognostic factor for both in the conventionally treated group. Doses in excess of 60 Gy resulted in increased fibrosis and a worse functional outcome. Extent of surgery was not an independent prognostic factor for limb function, although univariate analysis suggested an association with range of movement in the conventionally treated group (P less than 0.025). Despite significant objective loss of range of movement and muscle power patients retain excellent limb function and quality of life following limb conserving treatment. For optimal function, radiotherapy should be given with small fractions to a dose not exceeding 60 Gy.

Automatic image registration of diagnostic and radiotherapy treatment planning CT head images.

PURPOSE: Accurate image registration is an essential step to integrate information from diagnostic and radiotherapy treatment planning (RTP) CT images. In this paper a fully automatic algorithm is presented to quickly register such diagnostic and RTP CT head scans. METHODS AND MATERIALS: The registration algorithm, which regards one image as the moved version of the other, was applied to seven clinically obtained diagnostic and RTP CT data set pairs. During the RTP scan patients were in treatment position and wearing mold masks. Hence, patient position differed strongly in both image sets. Registrations were inspected visually and compared with results obtained minimizing the sum-of-square difference. RESULTS: Registrations were accurate upon visual inspection. Differences between the two algorithms were at subvoxel level. All cases were successfully registered, using several different starting points. Registration calculations took 1-2 minutes. Minimization of the sum-of-square difference took 1-1.5 hours. CONCLUSIONS: The results show that a fast and accurate image registration is achieved without prior segmentation or feature extraction and that the algorithm is robust, which makes it clinically applicable.

The impact of virtual simulation in palliative radiotherapy for non-small-cell lung cancer.

BACKGROUND AND PURPOSE: Radiotherapy is widely used to palliate local symptoms in non-small-cell lung cancer. Using conventional X-ray simulation, it is often difficult to accurately localize the extent of the tumour. We report a randomized, double blind trial comparing target localization with conventional and virtual simulation. METHODS: Eighty-six patients underwent both conventional and virtual simulation. The conventional simulator films were compared with digitally reconstructed radiographs (DRRs) produced from the computed tomography (CT) data. The treatment fields defined by the clinicians using each modality were compared in terms of field area, position and the implications for target coverage. RESULTS: Comparing fields defined by each study arm, there was a major mis-match in coverage between fields in 66.2% of cases, and a complete match in only 5.2% of cases. In 82.4% of cases, conventional simulator fields were larger (mean 24.5+/-5.1% (95% confidence interval)) than CT-localized fields, potentially contributing to a mean target under-coverage of 16.4+/-3.5% and normal tissue over-coverage of 25.4+/-4.2%. CONCLUSIONS: CT localization and virtual simulation allow more accurate definition of the target volume. This could enable a reduction in geographical misses, while also reducing treatment-related toxicity.

Optimisation of radiotherapy for carcinoma of the parotid gland: a comparison of conventional, three-dimensional conformal, and intensity-modulated techniques.

BACKGROUND AND PURPOSE: To compare external beam radiotherapy techniques for parotid gland tumours using conventional radiotherapy (RT), three-dimensional conformal radiotherapy (3DCRT), and intensity-modulated radiotherapy (IMRT). To optimise the IMRT techniques, and to produce an IMRT class solution. MATERIALS AND METHODS: The planning target volume (PTV), contra-lateral parotid gland, oral cavity, brain-stem, brain and cochlea were outlined on CT planning scans of six patients with parotid gland tumours. Optimised conventional RT and 3DCRT plans were created and compared with inverse-planned IMRT dose distributions using dose-volume histograms. The aim was to reduce the radiation dose to organs at risk and improve the PTV dose distribution. A beam-direction optimisation algorithm was used to improve the dose distribution of the IMRT plans, and a class solution for parotid gland IMRT was investigated. RESULTS: 3DCRT plans produced an equivalent PTV irradiation and reduced the dose to the cochlea, oral cavity, brain, and other normal tissues compared with conventional RT. IMRT further reduced the radiation dose to the cochlea and oral cavity compared with 3DCRT. For nine- and seven-field IMRT techniques, there was an increase in low-dose radiation to non-target tissue and the contra-lateral parotid gland. IMRT plans produced using three to five optimised intensity-modulated beam directions maintained the advantages of the more complex IMRT plans, and reduced the contra-lateral parotid gland dose to acceptable levels. Three- and four-field non-coplanar beam arrangements increased the volume of brain irradiated, and increased PTV dose inhomogeneity. A four-field class solution consisting of paired ipsilateral coplanar anterior and posterior oblique beams (15, 45, 145 and 170 degrees from the anterior plane) was developed which maintained the benefits without the complexity of individual patient optimisation. CONCLUSIONS: For patients with parotid gland tumours, reduction in the radiation dose to critical normal tissues was demonstrated with 3DCRT compared with conventional RT. IMRT produced a further reduction in the dose to the cochlea and oral cavity. With nine and seven fields, the dose to the contra-lateral parotid gland was increased, but this was avoided by optimisation of the beam directions. The benefits of IMRT were maintained with three or four fields when the beam angles were optimised, but were also achieved using a four-field class solution. Clinical trials are required to confirm the clinical benefits of these improved dose distributions.

Localised non-Hodgkin's lymphoma: the Sheffield Lymphoma Group experience (1970-1995).

We report a retrospective study of all patients with localised non-Hodgkin's lymphoma referred to the Sheffield Lymphoma Group (1970-1995). A total of 1,979 patients with non-Hodgkin's lymphoma were seen: 553 (28%) presented with stage I or II disease, 411 (21%) extranodal, 142 (7%) nodal. The commonest extranodal sites were head and neck, gastrointestinal tract, skin and central nervous system, accounting for 87% of patients. Most patients received primary localised radiotherapy. Overall observed survival was 52.5% at 5 years in the extranodal group and 65% in the nodal group. For both groups the 10-year observed survival was 42.5%. An age of 45 years and over was a poor prognostic factor in both groups (p<0.001). Patients with skin and non-Waldeyer's head and neck lymphomas survived best (5-year observed survivals 67 and 70% respectively) and CNS worst (5-year survival 38%). There is no cause for complacency in the management of localised non-Hodgkin's lymphoma, particularly for the less common extranodal sites where multicentre clinical studies are still essential.

VEDex (vincristine, epirubicin dexamethasone): an effective and well tolerated palliative chemotherapy regimen for non-Hodgkin's lymphoma.

An evaluation was carried out of the efficacy and toxicity of a novel weekly palliative chemotherapy regimen comprising vincristine, epirubicin and dexamethasone (VEDex) in 57 patients with non-Hodgkin's lymphoma (NHL) treated at this centre. The age range was 34-88 years and the median age was 67 years. Twenty-three patients (40%) had low grade disease and 4 patients (7%) had transformed NHL. Thirty patients (53%) had high grade NHL; 7 had relapsed after conventional chemotherapy and were not fit for high-dose chemotherapy, 7 were heavily pre-treated, 8 had received prior radiotherapy and 8 had not received any prior therapy. Responding patients received a total of 8 weeks of treatment, but treatment could be repeated at a later stage if required. The overall response rate was 66.6%; 11 patients (19.3%) achieved a complete response and 27 (47.3%) achieved a partial response. A further 11 patients (19.3%) had stable disease. Twenty-four patients (42.1%) reported complete resolution of symptoms and 21 (36.8%) had partial resolution of symptoms. The median survival from the onset of treatment was 6 months. Grade III neutropenia was seen in 9 patients (15.8%). Other toxicity included nausea and vomiting grade II (3.5%), grade III (1.8%) and alopecia grade III (1.8%). There were no treatment related deaths. We conclude that VEDex is an effective palliative treatment in patients with indolent or aggressive lymphoma with poor performance status or who have been heavily pre-treated. It is well tolerated in the elderly.

Primary intracerebral lymphoma: A clinicopathological study of 28 patients.

Primary intracerebral lymphoma is an uncommon presenting site for non-Hodgkin's lymphoma. The authors review 28 histopathologically confirmed, consecutive cases, presenting over a 15-year period. The cohort included 20 males and 8 females with a mean age at diagnosis of 54 years (range 27-75 years). Subtotal resection was performed in 8 patients. Radical whole brain irradiation was given to 27 patients. One patient was too unwell to receive treatment and quickly died. Three patients also had chemotherapy. Clinical remission was achieved in 19 patients. Of these, 9 relapsed after a median interval of 18 months. Nine patients (32% total cohort) are still alive and in remission after a median follow-up of 2 years and 10 months (range 11 months to 11 years and 5 months). Cause of death was intracerebral lymphoma in 13 of the 19 patients who died. Median survival was 12 months in this group (range 1 week to 4 years and 9 months). Actuarial 5-year survival for all patients was 19%. The prognosis for patients with primary intracerebral lymphoma treated with radiotherapy alone is poor.

Interval cancers in a randomized controlled trial of screening for colorectal cancer using a faecal occult blood test.

BACKGROUND: The sensitivity of unhydrated Haemoccult II has been examined in the context of a randomized controlled trial of faecal occult blood screening for colorectal cancer in Nottingham, UK. METHOD: Both traditional and proportional incidence methods were used to calculate sensitivity separately for both sexes, for two age groups at entry to the trial, for first screen and repeat screens and for three subsites within the large bowel. RESULTS: The traditional method of estimation yielded a sensitivity of 59% whereas the corresponding figure obtained using the proportional incidence method was 54%. The difference between the estimates using the two methods was greatest in subjects aged > or = 65 at entry to the trial and in cancers of the distal colon. CONCLUSIONS: The results suggest that there may be a higher proportion of slower growing tumours in subjects aged > or = 65 and that cancers occurring in the distal colon may have a longer mean sojourn time than cancers proximal to the sigmoid colon.

Cell kinetics of the in vitro metaphase arrest technique and the clinical applications.

The in vitro metaphase arrest technique (crypt cell production rate-CPPR) has been used to measure human rectal mucosal proliferation. Study of preincubation times, dose response curves and lag phases suggest that a concentration of vincristine of 5 micrograms/ml and 16 hour preincubation with time point increments between 25 and 125 minutes give optimal conditions for measuring rectal mucosal proliferation. Twenty individuals had rectal CCPR repeated without intervention of any kind. Close correlation was found between the two values (r = 0.89 and P = 0.0001). The effect of polyethylene glycol bowel preparation was also studied in 35 subjects. There was good correlation (r = 0.66, P = 0.007). There was close correlation between rectal and caecal CCPR as measured in 20 patients who had colonoscopy (r = 0.72, P = 0.0003). The in vitro metaphase arrest technique is a useful parameter of rectal mucosal proliferation and may be used with confidence in a number of different clinical situations.

Haemoccult screening for colorectal cancer: the effect of dietary restriction on compliance.

The aim of this study was to examine the effect of dietary restrictions on compliance with Haemoccult screening for colorectal carcinoma. One-hundred-and-fifty-three individuals were randomly allocated to perform Haemoccult tests with or without dietary restrictions, over 3 or 6 days. Those who failed to return completed tests within 6 weeks were sent a reminder letter. A small but significant improvement in compliance when testing over a 3-day period has been previously demonstrated but this difference was not seen in this study because of the small sample size. Overall, 72.8% compliance was achieved in those who were not asked to exclude certain foods during the test period compared with 51.8% in those in whom dietary restriction was requested (chi 2 = 7.45, P < 0.01). In a British population compliance with Haemoccult screening is adversely affected by the imposition of dietary restrictions.

Is dietary restriction always necessary in Haemoccult screening for colorectal neoplasia?

Certain dietary constituents may cause guaiac-based faecal occult blood tests to be positive in the absence of blood loss. In a randomized controlled study of Haemoccult screening for the early detection of colorectal cancer, a policy of retesting with appropriate dietary restriction is used to minimize false-positive results. Delay associated with the retesting protocol may cause considerable anxiety. The aim of the study was to determine the likelihood of an initial positive result remaining positive after retesting. One-hundred-and-thirteen of 137 (35.6%) subjects whose initial test was < 5 squares positive remained positive in contrast to 52/59 (88.1%) with > or = 5 squares positive, a significantly higher proportion (P < 0.001). This suggests that if five or more test squares are positive, then dietary interference is unlikely to be responsible. We conclude that, if dietary restriction retesting is practiced, individuals with strongly positive tests may be offered investigation without retesting, thus reducing their delay to further investigation.

Screening for colorectal cancer reduces emergency admissions.

AIMS: Colorectal cancer is common and accounts for over 15,000 deaths annually in England and Wales. Up to 30% of these patients require emergency surgery. Screening for colorectal cancer can reduce the mortality of colorectal cancer. This study addresses the impact of a population-based screening study on emergency admissions with colorectal cancer. METHOD: From 1981 a randomized trial of Faecal Occult Blood (FOB) screening has been undertaken in the Nottingham area, recruiting over 150,000 patients. The present study examined the records of patients enrolled in this study who presented as an emergency with colorectal cancer. RESULTS: Colorectal cancer was identified in 1962 cases, of which 468 (23.9%) presented as emergencies. The overall compliance was 60% (proportion of individuals completing at least one test). There were significantly fewer emergencies in the Screen-detected group compared with the Control group (P = < 0.0001). This group also had a significantly reduced 30-day mortality and a lower stoma rate than the Control group. Conversely the Non-responders had a significantly greater proportion of emergency admissions and a significantly increased stoma rate compared with the Control group. CONCLUSIONS: Screening for colorectal cancer using a faecal occult blood test can significantly reduce the number of emergency presentations with colorectal cancer. It is likely that the introduction of a national programme of screening for colorectal cancer would lead to increased compliance and that this would lead to a significant reduction in the emergency workload on the National Health Service from colorectal cancer.