Evaluation of physical performance of a scintillation dosemeter for patient dosimetry in diagnostic radiology

The physical performance of the patient scintillation dosemeter Skin Dose Monitor (SDM) was evaluated for use in diagnostic radiology. The SDM response was found to be linear, with output air kerma and output air kerma rate having a reproducibility in time lower than +/- 2.4%) (one standard deviation). A calibration protocol taking into account the more significant parameters, such as radiation quality dependence and the relative sensitivity of SDM detectors of the same batch, can be applied so that the maximum overall uncertainty is +/- 18% at the 95% confidence level. The SDM detectors did not show any loss of sensitivity during the 5-month period of evaluation. SDM performance was evaluated against thermoluminescent dosemeters (TLDs) (GR200A) by monitoring chest X-rays in 18 adult patients. The difference in entrance surface dose (ESD) values between the SDM and TLDs was less than 10%, but a lack of accuracy in ESD values of less than 0.3 mGy was observed. The main benefit of the SDM device compared with TLDs is the real-time read-out of dose combined with a better flexibility and rapidity of use for approximately the same cost per measurement. The SDM device is a good candidate for regular measurement of patient doses in diagnostic imaging departments as required under implementation of the European Council Medical Exposure Directive of 30 June 1997.     

Interlaboratory comparison of HER-2 oncogene amplification as detected by chromogenic and fluorescence in situ hybridization.

PURPOSE: Chromogenic in situ hybridization (CISH) is a new modification of the fluorescence in situ hybridization (FISH) technique for detection of oncogene amplification in archival tumor samples. In CISH, the oncogene probe is detected using a peroxidase reaction, allowing use of transmitted light microscopy. We compared detection of HER-2/neu amplification by CISH with a Food and Drug Administration-approved two-color FISH test in an interlaboratory setting. EXPERIMENTAL DESIGN: Formalin-fixed paraffin-embedded tumor samples from 197 breast cancers were analyzed for HER-2 amplification by CISH. Two-color FISH (PathVysion) CISH of 17 centromere was done if the observer considered it necessary to ascertain amplification status in tumors with borderline HER-2 CISH copy numbers. RESULTS: Paired CISH/FISH results were available from 192 (97%) of 197 cases, no clear difference in success rates of either method was observed. Centromere 17 CISH was considered necessary in seven tumors. CISH and two-color FISH results were concordant in 180 cases (93.8%). There were 92 and 88 tumors found HER-2 amplified and nonamplified, respectively, by both methods. Eight tumors were amplified by CISH but not by FISH, and four tumors exhibited the opposite condition (kappa coefficient 0.875). In 7 of 12 cases differences between the two methods could have related to a lack of CISH chromosome 17 information. The remaining cases were explained by difficult histology (ductal carcinoma in situ, poor representativity, dense lymphocytic infiltration, or intratumoral heterogeneity). CONCLUSIONS: These results indicate that CISH could provide an accurate and practical alternative to FISH for clinical diagnosis of HER-2/neu oncogene amplification in archival formalin-fixed breast cancer samples.     

Antineoplastic effects of partially HLA-matched irradiated blood mononuclear cells in patients with renal cell carcinoma.

PURPOSE: Vaccines, cytokines, and other biologic-based therapies are being developed as antineoplastic agents. Many of these agents are designed to induce an autologous immune response directed against the malignancy. In contrast, hematopoietic stem-cell transplantation is being developed as a form of allogeneic immunotherapy. This study tests the tolerance and antineoplastic activity of sequential infusions of partially HLA-matched allogeneic blood mononuclear cells (obtained from relatives) when administered outside of the context of a hematopoietic stem-cell transplantation. The cells are irradiated to prevent graft-versus-host disease. PATIENTS AND METHODS: Fifteen patients with relapsed or refractory malignancies for which no standard therapy was available were enrolled onto a clinical trial designed to assess the tolerability and antineoplastic effects of irradiated partially HLA-matched blood mononuclear cells obtained from relatives. RESULTS: There was disease regression in three patients with metastatic renal cell carcinoma during treatment. There was disease progression in six patients with metastatic renal cell carcinoma and two patients with metastatic melanoma during treatment. There was no change in disease state in several other patients. CONCLUSION: Irradiated allogeneic blood mononuclear cells administered outside the context of hematopoietic stem-cell transplantation may induce disease responses in patients with relapsed or refractory malignancies. Transfusion of irradiated allogeneic blood mononuclear cells should be developed further as a novel therapeutic antineoplastic approach.     

Tc-99m MDP uptake in uterine leiomyoma

A 47-year-old woman with adenocarcinoma of the right breast had bone scintigraphy with Tc-99m MDP. Bone imaging did not show any metastases. However, a large area of increased tracer uptake was seen extending from the abdomen to the pelvis. Abdominal ultrasound revealed a large solid and heterogeneous mass, measuring 18 x 11 x 14.3 cm, that originated in an empty uterus. A biopsy of the surgical specimen showed a leiomyoma of the uterus.     

Prolonged focal application of polyethylene glycol induces conduction block in guinea pig spinal cord white matter.

A 2-min focal application of Polyethylene Glycol (PEG) to injured mammalian spinal cords can offer significant yet limited restoration of functional and structural integrity. However, longer application of PEG has not been tested in similar injuries. In this study, isolated spinal cord white matter strips from adult guinea pigs were subjected to a 25 min exposure of PEG (MW: 2000; 50% w/w), with or without prior compression. When applied in a continuous steam, PEG, with a delay of about 6 min, suppressed the compound action potential (CAP) amplitude to 64+/-4% of the pre-PEG level in uninjured cords and to 64+/-7% in compressed cord strips. Both recovered to 70+/-5% (uninjured) and 88+/-11% (compressed) of the pre-PEG level following wash. When PEG was applied in a pulsatile manner, no significant decrease of CAP amplitude was observed. In summary, our results show that focal continuous application of PEG has minimal toxicity if applied for less than 5 min. Pulsatile application could extend this duration to at least 25 min with no toxicity. This study could be useful in determining the optimal protocol for the use of PEG in both animal research and human spinal cord victims.     

Tuberculosis notifications in Australia, 2003.

The National Notifiable Disease Surveillance System (NNDSS) received 982 tuberculosis (TB) notifications in 2003, of which 947 were new cases, 33 were relapses and two were cases with unknown history. The incidence of TB in Australia has remained at a stable rate since 1985 and was 4.9 cases per 100,000 population in 2003. The high-incidence groups remain people born overseas and Indigenous Australians at 19.9 and 8.7 cases per 100,000 population, respectively. By contrast the incidence in non-Indigenous Australians was 0.9 per 100,000. Comparison of the 2003 TB notification data against the performance indicators set by National Tuberculosis Advisory Committee highlights that enhanced TB control measures should be considered among these high-risk groups.     

Contrasting synaptic actions of the inhalational general anesthetics isoflurane and xenon

BACKGROUND: The mechanisms by which the inhalational general anesthetics isoflurane and xenon exert their effects are unknown. Moreover, there have been surprisingly few quantitative studies of the effects of these agents on central synapses, with virtually no information available regarding the actions of xenon. METHODS: The actions of isoflurane and xenon on gamma-aminobutyric acid-mediated (GABAergic) and glutamatergic synapses were investigated using voltage-clamp techniques on autaptic cultures of rat hippocampal neurons, a preparation that avoids the confounding effects of complex neuronal networks. RESULTS: Isoflurane exerts its greatest effects on GABAergic synapses, causing a marked increase in total charge transfer (by approximately 70% at minimum alveolar concentration) through the inhibitory postsynaptic current. This effect is entirely mediated by an increase in the slow component of the inhibitory postsynaptic current. At glutamatergic synapses, isoflurane has smaller effects, but it nonetheless significantly reduces the total charge transfer (by approximately 30% at minimum alveolar concentration) through the excitatory postsynaptic current, with the N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor-mediated components being roughly equally sensitive. Xenon has no measurable effect on GABAergic inhibitory postsynaptic currents or on currents evoked by exogenous application of GABA, but it substantially inhibits total charge transfer (by approximately 60% at minimum alveolar concentration) through the excitatory postsynaptic current. Xenon selectively inhibits the NMDA receptor-mediated component of the current but has little effect on the AMPA/kainate receptor-mediated component. CONCLUSIONS: For both isoflurane and xenon, the most important targets appear to be postsynaptic. The authors' results show that isoflurane and xenon have very different effects on GABAergic and glutamatergic synaptic transmission, and this may account for their differing pharmacologic profiles.