A Pilot Study of Stereotactic Body Radiotherapy and 177Lu-PSMA-617 for Oligometastatic Hormone Sensitive Prostate Cancer

PURPOSE/OBJECTIVE(S)

Stereotactic body radiotherapy (SBRT) is increasingly used for oligorecurrent prostate cancer (OPC). Despite excellent local control, distant metastasis free survival rates are more modest. We hypothesized SBRT outcomes could be optimized with improved staging imaging and integration of a well-tolerated targeted radiopharmaceutical therapy (RLT) for microscopic disease. We report initial results of a prospective, single-institution pilot (NCT05079698) of a novel, PSMA-based theranostic strategy for OPC.

MATERIALS/METHODS

Men with castrate sensitive OPC and 1-3 sites of PSMA PET avid disease ("index lesions") and no PSMA non-avid sites were eligible. No androgen deprivation therapy was permitted. Subjects first received 2 cycles of 177Lu-PSMA-617 RLT (7.47±0.14 GBq) spaced 6 weeks apart. In vivo dosimetry was performed during cycle 1. Four weeks post-cycle 2, patients were restaged with 68Ga-PSMA PET for an interim (post-RLT) response assessment. Index lesions were then consolidated with SBRT (9 Gy x 3) irrespective of post-RLT PET response. The primary outcome was feasibility defined as successful completion of protocol-mandated therapy without intercurrent distant failure on post-RLT PET.

RESULTS

Six men were treated with nine total index lesions (5 nodal, 3 osseous, 1 visceral). The study met its primary endpoint; all completed required interventions and no distant progression was seen on interim PSMA PET. Treatment was well tolerated; no grade 3+ toxicities, 2/6 had grade 2 toxicities (transient anemia and hyperbilirubinemia) and 5/6 had grade 1 toxicities. Median baseline lesion-level PSMA SUVmax was 16.8±8.7. Median interim SUVmax was 6.2±2.5 and declined for all but one lesion post-RLT (median -65%). Median SUVmax at 3-mos post-SBRT was 3.3±2.5 and decreased for all evaluable lesions (median -80%). Median baseline PSA was 2.01 ng/mL (range: 0.72-4.56) which declined in 5/6 post-RLT. The 6th patient experienced biochemical rise with interim PET showing only greater avidity in the known index lesion and SBRT was completed per protocol. All 4 evaluable patients with at least one post-SBRT follow-up have improved PSA at last visit (range 5.5-12 mos from cycle 1), and 2/4 have undetectable PSA. Composite dosimetry, correlatives and quality of life studies are forthcoming.

CONCLUSION

Our pilot study demonstrates the feasibility of a novel PSMA anchored theranostic strategy combining SBRT with targeted RLT for OPC. Preliminary data suggests promising outcomes, including the possibility of achieving an undetectable biochemical disease state without hormone therapy.

212 BUILT ENVIRONMENT OF NURSING HOMES AND INFECTION CONTROL AND PANDEMIC PREPAREDNESS

Background

The disproportionately high death rate of nursing home (NH) residents from COVID-19 in many countries, including Ireland, has focussed attention on infection prevention and control, including the built environment, in nursing homes. This has been a poorly researched topic to date, and we undertook a systematic review of evidence for architectural design measures which support infection control and pandemic preparedness.

Methods

Databases were screened for keywords related to NHs, built environment, infection prevention and control, and COVID-19; relevant papers were uploaded onto Covidence and screened for relevance. Data extracted from included articles was tabulated under 8 specific aspects of the built environment.

Results

Of 17 papers included in the final analysis, four studies found that larger nursing homes carried an increased risk of COVID-19 infection. Crowding in NHs was also a risk factor for infection, with a high crowding index associated with COVID-19 infection in five studies. Green House care homes, which are based on small clusters of domestic dwellings, fared better than traditional NHs. Two papers found an association between the location of NHs and the risk of COVID-19 infection, with urban NHs and those in areas of high prevalence being more at risk. Two papers identified internal fittings as a target for infection prevention and control. Seven papers highlighted the role of adequate ventilation in NHs in the prevention of spread of COVID-19. Only one paper described easy access to the outdoors as beneficial to infection control.

Conclusion

Residents of NHs are amongst the most vulnerable to COVID-19 infection. When designing and building NHs, the role of the built environment in controlling the spread of the virus should not be underestimated.

This research supported by Science Foundation Ireland.

Global upper-atmospheric heating on Jupiter by the polar aurorae

Jupiter's upper atmosphere is considerably hotter than expected from the amount of sunlight that it receives1-3. Processes that couple the magnetosphere to the atmosphere give rise to intense auroral emissions and enormous deposition of energy in the magnetic polar regions, so it has been presumed that redistribution of this energy could heat the rest of the planet4-6. Instead, most thermospheric global circulation models demonstrate that auroral energy is trapped at high latitudes by the strong winds on this rapidly rotating planet3,5,7-10. Consequently, other possible heat sources have continued to be studied, such as heating by gravity waves and acoustic waves emanating from the lower atmosphere2,11-13. Each mechanism would imprint a unique signature on the global Jovian temperature gradients, thus revealing the dominant heat source, but a lack of planet-wide, high-resolution data has meant that these gradients have not been determined. Here we report infrared spectroscopy of Jupiter with a spatial resolution of 2 degrees in longitude and latitude, extending from pole to equator. We find that temperatures decrease steadily from the auroral polar regions to the equator. Furthermore, during a period of enhanced activity possibly driven by a solar wind compression, a high-temperature planetary-scale structure was observed that may be propagating from the aurora. These observations indicate that Jupiter's upper atmosphere is predominantly heated by the redistribution of auroral energy.

The H3+ ionosphere of Uranus: decades-long cooling and local-time morphology

The upper atmosphere of Uranus has been observed to be slowly cooling between 1993 and 2011. New analysis of near-infrared observations of emission from H3+ obtained between 2012 and 2018 reveals that this cooling trend has continued, showing that the upper atmosphere has cooled for 27 years, longer than the length of a nominal season of 21 years. The new observations have offered greater spatial resolution and higher sensitivity than previous ones, enabling the characterization of the H3+ intensity as a function of local time. These profiles peak between 13 and 15 h local time, later than models suggest. The NASA Infrared Telescope Facility iSHELL instrument also provides the detection of a bright H3+ signal on 16 October 2016, rotating into view from the dawn sector. This feature is consistent with an auroral signal, but is the only of its kind present in this comprehensive dataset. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.

Modelling H3+ in planetary atmospheres: effects of vertical gradients on observed quantities

Since its detection in the aurorae of Jupiter approximately 30 years ago, the H3+ ion has served as an invaluable probe of giant planet upper atmospheres. However, the vast majority of monitoring of planetary H3+ radiation has followed from observations that rely on deriving parameters from column-integrated paths through the emitting layer. Here, we investigate the effects of density and temperature gradients along such paths on the measured H3+ spectrum and its resulting interpretation. In a non-isothermal atmosphere, H3+ column densities retrieved from such observations are found to represent a lower limit, reduced by 20% or more from the true atmospheric value. Global simulations of Uranus' ionosphere reveal that measured H3+ temperature variations are often attributable to well-understood solar zenith angle effects rather than indications of real atmospheric variability. Finally, based on these insights, a preliminary method of deriving vertical temperature structure is demonstrated at Jupiter using model reproductions of electron density and H3+ measurements. The sheer diversity and uncertainty of conditions in planetary atmospheres prohibits this work from providing blanket quantitative correction factors; nonetheless, we illustrate a few simple ways in which the already formidable utility of H3+ observations in understanding planetary atmospheres can be enhanced. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.

Why is the H3+ hot spot above Jupiter's Great Red Spot so hot?

Recent observations of Jupiter's Great Red Spot indicate that the thermosphere above the storm is hotter than its surroundings by more than 700 K. Possible suggested sources for this heating have thus far included atmospheric gravity waves and lightning-driven acoustic waves. Here, we propose that Joule heating, driven by Great Red Spot vorticity penetrating up into the lower stratosphere and coupling to the thermosphere, may contribute to the large observed temperatures. The strength of Joule heating will depend on the local inclination angle of the magnetic field and thus the observed emissions and inferred temperatures should vary with planetary longitude as the Great Red Spot tracks across the planet. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H₃⁺, H₅⁺ and beyond'.

The domination of Saturn's low-latitude ionosphere by ring 'rain'

Saturn's ionosphere is produced when the otherwise neutral atmosphere is exposed to a flow of energetic charged particles or solar radiation. At low latitudes the solar radiation should result in a weak planet-wide glow in the infrared, corresponding to the planet's uniform illumination by the Sun. The observed electron density of the low-latitude ionosphere, however, is lower and its temperature higher than predicted by models. A planet-to-ring magnetic connection has been previously suggested, in which an influx of water from the rings could explain the lower-than-expected electron densities in Saturn's atmosphere. Here we report the detection of a pattern of features, extending across a broad latitude band from 25 to 60 degrees, that is superposed on the lower-latitude background glow, with peaks in emission that map along the planet's magnetic field lines to gaps in Saturn's rings. This pattern implies the transfer of charged species derived from water from the ring-plane to the ionosphere, an influx on a global scale, flooding between 30 to 43 per cent of the surface of Saturn's upper atmosphere. This ring 'rain' is important in modulating ionospheric emissions and suppressing electron densities.

Breast Specialist Nurses – Expensive Hand Holding or Cost-Effective Counselling?

IntroductionCounselling breast cancer patients for reconstruction is complex and time consuming. Post-reconstruction satisfaction has been shown to be related to the quality of information provided to patients. Decisions regarding the type of breast reconstruction suitable for each patient is multi-factorial, including the autologous tissue available, general health, patient lifestyle and suitability, as well as patient preference. In our institution we offer a full range of reconstruction techniques. Initial pre-operative counselling is performed by a breast reconstruction specialist nurse at a consultation lasting at least 1 hour. During this time, all reconstructive options are discussed.Implications of surgery, photographs of post-operative results and the details of the procedures are explained and written information is provided. The option to meet a patient advocate at a later date is offered. An indication of the suitable reconstructive options available to the individual is given, however the surgeon, at a separate consultation lasting 10 minutes, performs the formal assessment of reconstructive type.MethodA comparison was made of patient satisfaction with pre-operative counselling and information giving, between those patients who were counselled by the operative surgeon alone and those counselled by the Breast Reconstruction Specialist nurse. A questionnaire to assess patient satisfaction with the reconstruction counselling was designed in conjunction with the Clinical Psychology team. This questionnaire was posted retrospectively to all patients who had undergone reconstruction counselling irrespective of whether they had subsequently undergone breast reconstruction. Patients were asked to respond to questions on a 5 point Likert scale. Patients were divided into 2 groups dependent on the person performing the counselling, ie. surgeon or nurse. All questionnaires were anonymous.ResultsQuestionnaires were allocated a random number and the data were analyzed independently by 2 separate clinical psychologists, blinded to which group the patients belonged to. Group 1 was counselled by the operative surgeon alone and Group 2 by the Breast Reconstruction Nurse. There was a very high response rate in both groups (70% in Group 1 and 71% in Group 2). Qualitative and quantitative data were analyzed separately. There was a high satisfaction rating in both groups with responses to all questions having a mean rating of above 4 out of 5. Patient satisfaction between the 2 groups was compared using the Mann-Whitney U test. There was no significant reported difference between how useful each of the groups found the contact.ConclusionEmploying a Specialist Nurse to perform the time-consuming pre-operative counselling for breast reconstruction is a cost effective measure, allowing Surgeons time to assess more patients or perform more appropriate skilled tasks instead. Patient satisfaction with the counselling service and information-giving was equal in both groups suggesting that nurse-led counselling, even for complex surgical procedures, is acceptable to patients. Having someone, other than the operative surgeon, give an independent and unbiased perspective on reconstructive options may be important in patient decision making.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1075.

Lack of induction of micronuclei in human peripheral blood lymphocytes treated with hydroquinone

Hydroquinone (HQ) has been reported to produce chromosomal effects in some in vivo and in vitro animal models. Its potential for inducing similar effects in human lymphocytes is less clear. The purpose of this study was to examine human lymphocytes treated with HQ for the presence of chromosomal anomalies, using an accepted assay for micronuclei. In addition, the stability of HQ in culture medium was determined to verify exposures. Lymphocyte cultures were obtained from eight donors so that variable responses amongst individuals could be assessed. The micronucleus assays utilized were a common 72 h assay with no wash, as well as two assay variations to maximize cell division. Assay variations consisted of either cell washing at 44 h or allowing unwashed cultures an extra 24 h recovery period before harvest. In all assays treatment was at 24 h post-mitogenic stimulation and cytochalasin B was added to stop dividing cells from undergoing cytokinesis. Thus, cells that were scored had undergone one division in the presence of the chemical. Stability results showed that while HQ was detectable in cultures at least for 15 h, it was considerably more stable at 25 than at 100 or 250 microM treatment levels. Results generated using any of the three micronucleus assay variations showed no significant increase in micronuclei in cultures treated with 12.5-200 microM HQ. Colchicine, the positive control and a known spindle disrupter, produced elevated levels of micronuclei. At certain HQ concentrations, a block in cell division was observed, as evidenced by a decrease in percent binucleated cells and replicative index end-points. By varying the assay conditions, cell cultures overcame this block in division and divided at HQ concentrations up to 200 microM, depending on the donor. The reversible block in cell division observed may be a protective response, allowing cells to recover without gross chromosomal damage. This study has substantially expanded the database with regard to the effects of HQ treatment on lymphocytes.

Hydroquinone: genotoxicity and prevention of genotoxicity following ingestion

Plant-derived polyphenolics and other chemicals with antioxidant properties have been reported to inhibit the expression of genotoxic activity by pro-oxidant chemicals (Sai et al., 1992, 1994; Teel and Castonguay, 1992). In vitro and in vivo studies with ionizing radiation suggest that hydroquinone (HQ) may have similar protective effects (Babaev et al., 1994). The present study was conducted to determine whether HQ is capable of inhibiting the induction of micronuclei in the bone marrow of mice following exposure to an oxidant, potassium bromate or KBrO3 (Nakajima et al., 1989; Sai et al., 1992, 1994). To be able to interpret the results of this work, it was also necessary to determine whether HQ is itself genotoxic when fed in the diet. HQ diets (0.8%) fed to mice for 6 days reduced the background incidence of micronuclei compared with the basal diet. KBrO3 dosed ip (12.5-100 mg/kg) produced a dose-dependent increase in micronuclei as reported by others. Mice fed 0.8% HQ diets 6 days, and then dosed intraperitoneally with KBrO3, showed a 36% reduction in micronuclei across the range of KBrO3 dose levels. This effect was associated with a reduction in the background micronucleus response as well as a reduction in response to KBrO3. Statistical significance (P < or = 0.05), observed at a dose of 25 mg/kg KBrO3 in the mice fed the control diet, was abolished in the group fed 0.8% HQ. When mice were given 50 mg HQ/kg by oral gavage and then given 50 mg KBrO3/kg ip 20 min later, the micronucleus response induced by KBrO3, was lower in animals given HQ. The results of this study demonstrate that large doses of HQ may be given orally without induction of micronuclei or bone marrow depression, that HQ reduces the background micronucleus response in animals fed a basal diet, and that the HQ reduces the micronucleus response to KBrO3 as well as background incidence of micronuclei in KBrO3-dosed animals. The protective effect of HQ may be due to enzyme induction or a direct antioxidant effect of HQ against oxidants commonly present in the diet.

Depigmentation with tert-butyl hydroquinone using black guinea pigs

tert-Butyl hydroquinone (TBHQ) has important and functional uses in consumer and commercial applications, some of which involve human exposure primarily through dermal contact. To assist in the safety evaluation of TBHQ, this study was conducted to determine whether TBHQ would produce changes in skin pigmentation after repeated dermal application to black guinea pigs. Hydroquinone (HQ) and hydroquinone monomethyl ether (HQMME) were used as positive controls. TBHQ and HQ were tested at concentrations of 0.1, 1.0 and 5.0%, while HQMME was tested at a concentration of 10.0%. Groups of five males and five females were dosed with TBHQ, HQ, or the vehicle (hydrophilic ointment) daily (M-F) for 13 weeks. In addition, animals (five males, five females) treated with HQMME received 13 doses over a 3-week period. The application site was evaluated weekly for degree of pigmentation loss and irritation. Twenty-four hours after final application, sites were evaluated for depigmentation, irritation and hyperpigmentation. Subsequently, the application site was depilated and re-evaluated for the same endpoints. Repetitive exposure to concentrations of 1.0% and 5.0% TBHQ and HQ were slightly to moderately irritating, while 0.1% of each of these test materials produced only weak irritant responses. No irritant responses to hydrophilic ointment were observed and HQMME produced weak irritant responses after 2 weeks. Neither 0.1% TBHQ nor HQ produced depigmentation, while 20% of animals dosed with 1.0% TBHQ and 30% of animals dosed with 1.0% HQ had spotty or uniform loss of pigment at the site of treatment. Approximately 40% of animals dosed with 5% TBHQ or HQ were depigmented at the treatment site at the final evaluation. HQMME produced complete depigmentation of the skin and hair in all animals. Hyperpigmentation of the treatment site was observed in 80-100% of animals in all groups (with the exception of HQMME-treated animals, treated for only 3 weeks), which may be attributable to the use of hydrophilic ointment as the vehicle, the application procedure, or simply clipping hair from the skin. Thus, this study showed that TBHQ causes depigmentation in black guinea pigs at concentrations of 1% or greater, but that a no-effect threshold for this endpoint exists at a concentration between 0.1 and 1.0%.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

Evaluation of a sustained 7-year health education campaign on leprosy in Rufiji District, Tanzania

To assess the impact of a 7-year intensive health education campaign about leprosy delivered by workers of the Kindwitwi Leprosy Trust to schoolchildren and general public in Rufiji District. Knowledge, attitude and beliefs towards leprosy were measured in Rufiji and compared to neighbouring Kisarawe District as control. Lessons learned from this analysis may be useful for the planning and evaluating of health education campaigns. Interview of schoolchildren, general public, community leaders, traditional healers and medical staff in both districts. A stratified randomized sampling scheme was used, with stratification for urban and rural settings. A representative sample of schoolchildren, general public, community leaders, traditional healers and medical staff in Rufiji District and in the control area of Kisarawe District was interviewed. The interviews were partly structured and partly open. The results of the interviews were analysed in the context of epidemiological leprosy data from 1985 till 1995, and demographic data of both districts. Data entry and statistical analysis was done using FileMaker Pro, Stata and Excel computer packages. We did not observe positive effects of the health education campaign on the indicators regarding early diagnosis of leprosy with less disability. Leprosy case detection was declining in both districts. We found that the campaign had a favourable impact on the knowledge and the attitude of schoolchildren in Rufiji District. We could demonstrate a relationship between increased knowledge of leprosy and a positive, less stigmatizing attitude. Knowledge of leprosy was better in Rufiji as compared to Kisarawe, but only among schoolchildren. We found indications that low level of education, rural residence, older age, female gender and Moslem religion were associated with stigmatizing attitudes and beliefs towards leprosy. Knowledge about leprosy reactions among medical staff interviewed was not optimal. The exact outcome of the sustained campaign in Rufiji District was difficult to assess because no comparison could be made with the situation prior to the campaign. However, the health education campaign was associated with increased knowledge and diminished tendency to stigmatize leprosy among schoolchildren. Health education campaigns have to be sustained and have to cover a broad sector of the society in order to induce behavioural changes in the community. The focus of health education should be rural communities and schools, and pay special attention to women, religious leaders and traditional healers. Awareness of diagnosis and treatment of leprosy reactions among medical staff should be improved.

A code of ethics for the medical dosimetrist--the American Association of Medical Dosimetrists experience

The Committee on Protocol and Ethics of the American Association of Medical Dosimetrists (AAMD) has developed a Code of Ethics for a radiation oncology society of medical dosimetrists. The purpose of the code of ethics is fourfold: (1) Establish an ideal of professional conduct specific to the medical dosimetry profession; (2) Develop a statement of the moral values and commitment of the AAMD; (3) Recognize professional relationships and obligations; and (4) Define goals to which the medical dosimetrist should aspire. The Code of Ethics was adopted as AAMD policy in October 1995.

Mucin-like carcinoma associated antigen (MCA) at presentation with breast cancer

The usefulness of serum measurements of mucin-like carcinoma associated antigen (MCA) in 100 women at presentation with breast cancer was evaluated. Peripheral venous blood was drawn and MCA values determined by radioimmunoassay. Twenty women presenting with benign breast disease and 20 normal women served as controls. There was no difference in the MCA values between the benign breast disease group and the normal group: 4.1 +/- 0.9 units/ml versus 5.0 +/- 0.75 units/ml (mean +/- sem). The following were the MCA values for patients by stage; stage 1: 11.2 +/- 1.02, stage 2: 11.0 +/- 1.29, stage 3: 20.2 +/- 6.7, stage 4: 31 +/- 5.0. Statistical analysis of stage versus controls showed significant elevations only in stage 3 and 4 disease (p < 0.05). We conclude that MCA may be a useful serum tumour marker only in advanced breast cancer but is unreliable in detection of early breast cancer.

Zimbabwe's AIDS action programme for schools: a case study

AIDS is the leading cause of death amongst adults in Zimbabwe and the major contributor to rising rates of infant, child and maternal mortality. About 9% of the population are HIV-positive and the number of orphans due to AIDS is projected to reach 600,000 by the year 2000. Around 90% of HIV transmission in Zimbabwe happens through heterosexual intercourse.

Animal behavioral methods in neurotoxicity assessment: SGOMSEC joint report

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N-myc gene copy number in neuroblastoma cell lines and resistance to experimental treatment

The N-myc oncogene is amplified in approximately 30% of neuroblastomas. It is well established that cases of neuroblastoma with amplified N-myc have markedly poorer prognosis than those in which N-myc copy number is not elevated. The mechanism for this association is not known but may be related to cellular resistance to radiation or cytotoxic drugs. Seven human neuroblastoma cell lines were used to investigate the relationship between N-myc copy number or expression and sensitivity to ionising radiation and to cisplatin. N-myc copy number was assessed by Southern blotting and hybridisation using the p-Nb1 probe. The signal produced by DNA from the cell lines was compared with that of single copy N-myc from normal human placental DNA. A range of N-myc copy numbers from 1 to 800 was found. Expression levels of N-myc mRNA were compared by "dot blotting" and subsequent hybridisation to the p-Nb1 probe. Radiosensitivity was assessed by surviving fraction at 2 Gy (SF2) following 60Co gamma irradiation. Values ranged from 0.13 to 0.52. Sensitivity to cisplatin was indicated by comparison of isoeffective concentrations (concentration required to produce 1 log cell kill). These ranged from 7.5 to 13 microM. Cisplatin studies showed a correlation between N-myc copy number (though not expression) and resistance to this drug. If this relationship is causal it may explain why treatment fails in those patients with an elevated N-myc copy number. However, no correlation was found between N-myc copy number or expression and sensitivity to radiation. It is possible that N-myc amplification confers resistance to some but not all treatments used in the therapy of neuroblastoma. Further investigations along these lines may lead to the identification of agents which are most appropriate for the treatment of neuroblastoma with amplified N-myc gene.

Microvascular replantation of a completely avulsed scalp

Total scalp avulsion is an unusual injury. To obtain good functional and cosmetic results, immediate revascularization using microsurgical techniques and replacement of the scalp in the correct anatomical position is the procedure of choice. This article describes a case report of successful replantation of a totally avulsed scalp from a 26-year-old male. Bilateral superficial temporal vessel anastomoses were performed using reversed autologous long saphenous vein grafts on the right side and direct repair on the left. Points of technique are discussed and the literature is reviewed.

An analysis of the diagnostic accuracy of endoscopic biopsy and cytology in the detection of oesophageal malignancy

The role of combined cytohistological examination in the differentiation of benign from malignant oesophageal mucosal lesions was studied in 331 patients. Malignancy was confirmed by specimen histopathology in 58 patients. Both endoscopic biopsy and cytology were positive in 41 (71%) patients. Endoscopic biopsy alone suggested malignancy in 10 cases (17%) while cytology was positive after negative biopsy in seven (12%). Cytology yielded four false positive and 10 false negative results giving a sensitivity level of 81%, a specificity of 98% and a positive predictive value for oesophageal malignancy of 92%. Histology on the other hand yielded one false positive and seven false negative results providing a sensitivity of 87%, a specificity of 99% and a positive predictive value of 96%. No patients were left undiagnosed using both diagnostic modalities; cytology increased the diagnostic yield from 87% to 100%. Exfoliative cytology was most valuable in the diagnosis of tumours of the lower one-third of the oesophagus where seven of 31 malignancies (23%) were identified by this method alone (P less than 0.05). Neither the histological type of the tumour nor the morphological appearance was found significantly to affect the diagnostic yield (P greater than 0.05). We conclude that cytological examination should be standard practice in the investigation of oesophageal lesions.

A 14-week vapor inhalation toxicity study of methyl isobutyl ketone

In a 2-week probe study male and female Fischer-344 rats and B6C3F1 mice were exposed 6 hr/day to 2000, 500, 100, or 0 ppm methyl isobutyl ketone (MIBK). At 2000 ppm there was a slight increase in male rat liver weight (absolute and relative). The only changes observed histologically were increases in regenerative tubular epithelia and hyalin droplets in kidneys of male rats exposed to 2000 or 500 ppm. Exposure levels for a subchronic study were 0, 50, 250, or 1000 ppm methyl isobutyl ketone vapors 6 hr/day, 5 days per week, for 14 weeks. The 14 weeks of exposure had no adverse effect on the clinical health or growth of rats or mice. Male rats and male mice exposed to 1000 ppm MIBK had a slight but statistically significant increase in liver weight and the liver weight/body weight ratio. Liver weight was also increased slightly in male mice exposed to 250 ppm. No gross or microscopic hepatic lesions related to MIBK exposure were observed. Furthermore, the only microscopic change observed was an increase in the incidence and extent of hyalin droplets within proximal tubular cells of the kidneys of male rats exposed to 250 and 1000 ppm of MIBK. The relevance of the male rat kidney tubular effect to humans is not known. In conclusion, other than the male rat kidney effect, exposure of male and female rats and mice to MIBK at levels up to 1000 ppm for 14 weeks was without significant toxicological effect.

Radiobiological considerations in the treatment of neuroblastoma by total body irradiation

Neuroblastoma is a radiosensitive neoplasm for which total body irradiation (TBI) is presently under clinical consideration. Collated data on the radiobiology of human neuroblastoma cells in vitro (11 cell lines derived from seven patients) indicates moderate cellular radiosensitivity and low capacity for accumulation of sublethal damage (median survival curve parameters: Do = 104 cGy, Dq = 32 cGy, n = 1.36). Mathematical studies incorporating these parameters suggest that low dose fractionated TBI is unlikely to achieve significant levels of tumour cell kill. When high dose TBI is used in conjunction with bone marrow rescue a tumour "log cell kill" of 4-5 should be achievable. This effect would be additional to that achieved by chemotherapy. The optimum schedule for exploitation of radiobiological differences between neuroblastoma cells and the dose-limiting normal tissues has a hyperfractionated structure. Twice-daily treatments with fraction sizes in the region 120-150 cGy seems appropriate. Single dose treatments at high dose rate are contraindicated. Fractionated TBI with bone marrow rescue may be curative for some patients in clinical remission who are presently destined to relapse.

Radiation studies on multicellular tumour spheroids derived from human neuroblastoma: absence of sparing effect of dose fractionation

In vitro experiments were carried out to compare the effects of single-dose and split-dose irradiation on a cell line (NB1-G) derived from human neuroblastoma and grown as multicellular tumour spheroids (MTS). The radiation response was evaluated in terms of regrowth delay; estimates of in situ cell survival were made by back-extrapolation of regrowth curves. These studies showed no significant difference in the effectiveness of single as compared to split dose irradiation i.e. no sparing effect of fractionation. If MTS constitute a realistic model for micrometastases in vivo, these results provide a radiobiological rationale for hyperfractionated treatment regimes in the adjuvant radiotherapy of neuroblastoma.

The radiosensitivity of human neuroblastoma cells estimated from regrowth curves of multicellular tumour spheroids

Multicellular tumour spheroids may provide a suitable in-vitro model for micrometastases in vivo. In this paper, the results are reported of experimental studies on the radiation response of two lines of spheroids derived from human neuroblastoma. Spheroids of approximately 200-250 microM mean diameter were exposed to graded doses of X rays (50-350 cGy) and, following a static or regression phase, regrew at rates which approximated those of unirradiated spheroids. Clonogenic surviving fraction was estimated, at each dose level, by extrapolation of the regrowth curve to zero dose. It is proposed that this procedure is more suitable for regrowth curves of spheroids than in-vivo tumours, because of the absence in vitro of complicating factors which occur only in vivo. By this means, survival curves were deduced and were found (for both cell lines) to be almost exponential in form, with little indication of capacity for accumulation of sublethal damage (multitarget parameters: DQ values: 17 and 25 cGy; Do values: 104 and 81 cGy respectively). These results contribute to the evidence for high radiosensitivity of neuroblastoma cells in vitro and provide a rationale for the use of hyperfractionation in the clinical treatment of neuroblastoma by radiotherapy.

Assessment of Hitachi HME-20 pulse and blood-pressure monitor

The performance of the Hitachi HME-20 pulse and blood-pressure (BP) monitor in comparison with direct intra-arterial BP recording and electrocardiographic monitoring is described. Highly significant (p less than 0.001) correlations were found between intra-arterial systolic and diastolic pressures and pressures recorded by the Hitachi monitor. Similarly, the electrocardiographically computed heart-rate, and that given by the Hitachi monitor were significantly correlated (p less than 0.001). Systolic blood-pressure was underestimated by a mean of -12 mmHg and tended to become more erroneous when intra-arterial pressure was greater than 150 mmHg. These results are comparable to more expensive pulse and blood-pressure monitors. We conclude that the instrument can reproduce a satisfactory estimate of heart-rate and blood-pressure and may be of particular use when a change of blood-pressure is of prime importance, rather than an absolute measurement.

The suitability of diazochrome KBL film for UV dosimetry

A promising material for use in a UV film badge dosemeter is diazo film. The optical density of this substance changes on exposure to ultraviolet radiation. The present paper reports some of the relevant factors in the processing of the film and also on its spectral sensitivity. It is evident from our results that development time and volume and concentration of ammonia solution should be standardised. However, after the film has been developed, it is not affected by subsequent UV exposure or by storage for up to one month. Although maximum sensitivity occurs at 405 nm, there is still an easily measurable response at 254 nm. It is concluded that provided procedures are standardised, Diazochrome KBL film is an inexpensive, convenient material for a UV film badge dosemeter with measurable sensitivity down to 254 nm.