Blood-Brain Barrier Injury following Intracarotid Injection of Radiographic Contrast Media

Changes in signal intensity of the brain at magnetic resonance (MR) imaging before and after Gd-DTPA were used for in vivo quantification of injury to the blood-brain barrier (BBB). Immediately following intracarotid injection of 2 ml/kg of radiographic contrast medium (CM) 0.4 mmol/kg of Gd-DTPA was injected intravenously. MR imaging was performed with a 400/25 partial saturation pulse sequence. The maximum percentage changes (mean ± SD) in signal intensity of the brain after CM and Gd-DTPA were 1.6±1.6% with saline, 3.2 ± 2.0% with iotrolan, 4.3 ± 1.7% with iohexol, 6.6 ± 3.6% with ioxaglate and 8.2 ± 3.6% with diatrizoate. Not only the osmolality but also the ionicity and chemotoxicity seemed to influence Gd-DTPA leakage. A subtle BBB injury had a stronger tendency to occur in the basal ganglia than in the cerebral cortex. MR enhancement is proposed as a sensitive method for in vivo quantification of the BBB injury caused by intracarotid CM injection.

Acute Electrolyte Disturbances in Coronary Sinus during Left Coronary Arteriography in Man

Electrolyte disturbances, particularly reduction of ionized calcium, induced by iodinated contrast media (CM) are important considerations in coronary arteriography. A study was conducted in 24 patients to evaluate the acute electrolyte alterations in the coronary sinus during left coronary arteriography. During left coronary arteriography, coronary sinus blood was withdrawn for measurement of electrolytes. The CM used were diatrizoate, ioxaglate, iohexol, and iopamidol. The hematocrit was decreased moderately by all 4 CM used at 5 s and returned to the control level at 15 s. The level of ionized calcium was decreased by all CM at 5 s. Prolonged reduction of ionic calcium was observed with diatrizoate and ioxaglate at 15 s. The level of potassium was almost unchanged by diatrizoate and ioxaglate in spite of hemodilution, which may lead us to a hypothesis that potassium can be released from the intracellular spaces such as red blood cells and vascular endothelial cells. Thus the depression of left ventricular function might be caused not only by reduction of ionized calcium, but also by a relative increase in the level of serum potassium.

Effects of Contrast Media on the RR and QT Interval during Coronary Arteriography

During coronary arteriography, transient prolongation of the RR and QT intervals can be observed to occur. Animal experiments have suggested that low-osmolality contrast media have less effect, but there have been few clinical studies of this phenomenon. We analyzed 95 electrocardiographic records from patients who had undergone coronary arteriography and assessed the maximal prolongation of the RR and QT intervals. The contrast media used for arteriography included meglumine sodium diatrizoate, iopamidol, iohexol, and meglumine sodium ioxaglate. Diatrizoate caused the greatest electrocardiographic changes. Among the low osmolality contrast media, ioxaglate caused the smallest bradycardial effect and iohexol the smallest prolongation of the QT interval. It appears necessary to consider some additional factors for osmolality or ionicity, such as the chemotoxicity of the chemical structure of the iodinated contrast medium moiety, when assessing their potential adverse effect on the cardiac conduction system.

Mitigation of methane production from cattle by feeding cashew nut shell liquid

The effects of cashew nut shell liquid (CNSL) feeding on methane production and rumen fermentation were investigated by repeatedly using 3 Holstein nonlactating cows with rumen fistulas. The cows were fed a concentrate and hay diet (6:4 ratio) for 4 wk (control period) followed by the same diet with a CNSL-containing pellet for the next 3 wk (CNSL period). Two trials were conducted using CNSL pellets blended with only silica (trial 1) or with several other ingredients (trial 2). Each pellet type was fed to cows to allow CNSL intake at 4 g/100 kg of body weight per day. Methane production was measured in a respiration chamber system, and energy balance, nutrient digestibility, and rumen microbial changes were monitored. Methane production per unit of dry matter intake decreased by 38.3 and 19.3% in CNSL feeding trials 1 and 2, respectively. Energy loss as methane emission decreased from 9.7 to 6.1% (trial 1) and from 8.4 to 7.0% (trial 2) with CNSL feeding, whereas the loss to feces (trial 1) and heat production (trial 2) increased. Retained energy did not differ between the control and CNSL periods. Digestibility of dry matter and gross energy decreased with CNSL feeding in trial 1, but did not differ in trial 2. Feeding CNSL caused a decrease in acetate and total short-chain fatty acid levels and an increase in propionate proportion in both trials. Relative copy number of methyl coenzyme-M reductase subunit A gene and its expression decreased with CNSL feeding. The relative abundance of fibrolytic or formate-producing species such as Ruminococcus flavefaciens, Butyrivibrio fibrisolvens, and Treponema bryantii decreased, but species related to propionate production, including Prevotella ruminicolla, Selenomonas ruminantium, Anaerovibrio lipolytica, and Succinivibrio dextrinosolvens, increased. If used in a suitable formulation, CNSL acts as a potent methane-inhibiting and propionate-enhancing agent through the alteration of rumen microbiota without adversely affecting feed digestibility.

Transglutaminase-mediated in situ hybridization (TransISH) system: a new methodology for simplified mRNA detection

Detection and localization of specific DNA or RNA sequences in cells and tissues are of great importance for biological research, diagnosis, and environmental monitoring. However, the most common procedure for in situ hybridization employs laborious immunostaining techniques. In the present study, we report proof-of-concept for a new RNA-enzyme conjugated probe for the detection of mRNA on tissue sections with a simple procedure. An RNA probe modified with a specific dipeptide substrate of transglutaminase was prepared. Alkaline phosphatase was then covalently and site-specifically combined to the dipeptide-labeled RNA using microbial transglutaminase. The new RNA probe labeled with alkaline phosphatase was validated by in situ hybridization (ISH) and proved to be a sensitive and sequence specific probe for mRNA detection in tissues. The new transglutaminase-mediated ISH (TransISH) strategy is free from antigen-antibody reaction, leads to one-step signal amplification after hybridization, and thus will be widely applicable for highly sensitive nucleic acid detection.

Transglutaminase-mediated synthesis of a DNA-(enzyme)n probe for highly sensitive DNA detection

A new synthetic strategy for DNA-enzyme conjugates with a novel architecture was explored using a natural cross-linking catalyst, microbial transglutaminase (MTG). A glutamine-donor substrate peptide of MTG was introduced at the 5-position on the pyrimidine of deoxyuridine triphosphate to prepare a DNA strand with multiple glutamine-donor sites by polymerase chain reaction (PCR). A substrate peptide that contained an MTG-reactive lysine residue was fused to the N terminus of a thermostable alkaline phoshatase from Pyrococcus furiosus (PfuAP) by genetic engineering. By combining enzymatically the substrate moieties of MTG introduced to the DNA template and the recombinant enzyme, a DNA-(enzyme)(n) conjugate with 1:n stoichiometry was successfully obtained. The enzyme/DNA ratio of the conjugate increased as the benzyloxycarbonyl-L-glutaminylglycine (Z-QG) moiety increased in the DNA template. The potential utility of the new conjugate decorated with signaling enzymes was validated in a dot blot hybridization assay. The DNA-(enzyme)(n) probe could clearly detect 10(4) copies of the target nucleic acid with the complementary sequence under harsh hybridization conditions, thereby enabling a simple detection procedure without cumbersome bound/free processes associated with a conventional hapten-antibody reaction-based DNA-detection system.

Phylogenetic diversity of gene sequences isolated from the rumen as analysed using a self-organizing map (SOM)

AIMS

To determine the origins of DNA sequences isolated from the rumen microbial ecosystem using a self-organizing map (SOM).

METHODS AND RESULTS

DNA sequences other than 16S small subunit ribosomal RNA (SSU rRNA) gene sequences that were detected from the rumen were analysed by the SOM method reported by Abe et al. [2000, Self-Organizing Map (SOM) unveils and visualizes hidden sequence characteristics of a wide range of eukaryote genomes. Gene 365, 27-34]. Because query sequences positioned by SOM were scattered on the master drawing of SOM, it was suggested that many DNA sequences isolated from the rumen were collected from a broad range of micro-organisms. Although the results obtained by SOM were similar to those obtained by the neighbour-joining (NJ) method, SOM was able to presume the phylotypes of the query sequences without information about the 16S SSU rRNA gene sequences and homology searches, and to reveal existence of novel micro-organisms deduced to be cellulolytic bacteria, archaea and methanotrophic bacterium.

CONCLUSIONS

As the SOM method defined phylotypes of unreported rumen micro-organisms, it is presumed that these phylotypes would be involved in rumen fermentation in cooperation with known rumen micro-organisms. Moreover, it is demonstrated that SOM is a useful tool for affiliating DNA sequences, which have no matches in databases.

SIGNIFICANCE AND IMPACT OF STUDY

Through SOM analysis, a better means of identifying rumen micro-organisms and estimating their roles in rumen function was provided.

Diversified expression patterns of autotaxin, a gene for phospholipid-generating enzyme during mouse and chicken development

Autotaxin (ATX), or nucleotide pyrophosphatase-phosphodiesterase 2, is a secreted lysophospholipase D that generates bioactive phospholipids that act on G protein-coupled receptors. Here we show the expression patterns of the ATX gene in mouse and chicken embryos. ATX has a dynamic spatial and temporal expression pattern in both species and the expression domains during neural development are quite distinct from each other. Murine ATX (mATX) is expressed immediately rostral to the midbrain-hindbrain boundary, whereas chicken ATX (cATX) is expressed in the diencephalon and later in the parencephalon-synencephalon boundary. In the neural tube, cATX is expressed in the alar plate in contrast to mATX in the floor plate. ATX is also expressed in the hindbrain and various organ primordia such as face anlagen and skin appendages of the mouse and chicken. These results suggest conserved and non-conserved roles for ATX during neural development and organogenesis in these species.

Film tomography as a tool for three-dimensional image construction and gene expression studies

In order to observe three-dimensional (3D) expression patterns of genes in whole animals, whole organs, or whole tissues, in situ hybridization (ISH) of many sections must be carried out and then used to construct a 3D image. For this purpose, we have developed an automatic microtome to prepare tissue sections with an adhesive film. We used commercially available film suitable for sectioning and ISH. We constructed a microtome and, after adherence of the film to a paraffin-embedded tissue block, cut the block with a blade to prepare sections on film. Then, the sections-on-film were automatically set in a plastic frame that was the same size as a conventional glass slide. With this automatic microtome, tissue sections can be made for ISH or immunohistochemistry in addition to conventional hematoxylin and eosin staining without specific training. We demonstrate that we can construct 3D images of gene expression patterns obtained by ISH on sections prepared with this automatic microtome. We have designated this method as 'Film Tomography (FITO)'.

Health-related quality-of-life after external beam radiation therapy for localized prostate cancer: intensity-modulated radiation therapy versus conformal radiation therapy

We compared health-related quality-of-life (HRQL) after intensity-modulated radiotherapy (IMRT) with statuses obtained after old and new protocols of three-dimensional conformal radiation therapy (3DCRT) for localized prostate cancer. We measured the general and disease specific HRQL using the MOS 36-Item Health Survey (SF-36), and the University of California, Los Angeles Prostate Cancer Index (UCLA PCI), respectively. IMRT resulted in similar profiles of general and disease-specific HRQL to two other methods within the first year after treatment. Moreover, IMRT gave rise to comparable urinary, intestinal and sexual side effects despite the high dose of radiation applied.

Safety and efficacy trial of preoperative sequential chemo-radiation therapy for the surgery sparing treatment (SST) in early breast cancer (EBC): Japan Clinical Oncology Group trial (JCOG0306)

10717

Background: The combination of preoperative anthracycline-containing regimen and taxane can obtain a pathological complete response (pCR) rate of around 30% for patients (pts) with EBC. To pursue higher pCR rate with maintaining good systemic control is necessary to put the SST practical in the future. The objective of this trial was to determine whether the addition of radiation therapy (RT) to chemotherapy (CT) could surpass the pCR rate of 50% in pts with EBC. Methods: We conducted a safety and efficacy trial of CT (4 courses of doxorubicin and cyclophosphmide (60/600 mg/m2) followed by 12 courses of weekly paclitaxel (80 mg/m2) and RT (whole breast 45Gy + boost 10Gy) sequentially as a primary therapy in pts with stage I-IIIA (5.0 cm ≥ tumor size ≥ 2.0 cm) BC. All pts received mastectomy or lumpectomy 12–16 weeks after completion of RT to maximize the effect of RT. pCR was assessed by the central pathological review board according to the pCR classification adopted by the National Surgical Adjuvant Breast and Bowel Project (NSABP). The study was designed to enroll 104 eligible pts with threshold pCR 35%, expected pCR 50%, alpha 0.05, beta 0.1, and additionally to have the width of 95% confidence interval (CI) within ±10% for sufficient precision of pCR. Results: Between June 2004 and April 2005, 108 pts were enrolled in this trial. Median age was 50 years (range 23–69). 1 pt had T1, 95 T2, and 3 T3 tumors (2 pts’ data are missing and 7 pts’ data have not been collected). 58% (59/101) were ER+, 49% (49/101) were PgR+ and 31% (31/101) had HER2 overexpression. Based on the planned interim analysis, the Data Monitoring Committee recommended to terminate the trial for insufficient pCR rate of the first 7 eligible patients (0% (0/7), 95% CI: 0–41.0%). Toxicities were within expected range. Conclusions: Preoperative sequential chemo (AC followed by paclitaxel) -radiation therapy is not considered to be promising for accomplishing enough pCR rate.

No significant financial relationships to disclose.

Short Communication: Amino Acids Antagonistic to the Amino Acids Inhibitory for Growth Rate of Mixed Ruminal Bacteria

Antagonism of some amino acids (AA) to the inhibitory effects of other AA (Ile, Phe, and Thr) on the growth rate of mixed ruminal bacteria was investigated. In vitro growth rate of the mixed ruminal bacteria was inhibited when the 3 inhibitory AA (1 mM each) were each added to individual control treatments in which an ammonium salt was included as a sole N source. The inhibitory effect caused by Ile was relieved by addition of Leu or Val (equimolar to Ile), and no significant inhibition was shown when both Leu and Val were added together with Ile. The growth inhibition caused by Phe was also alleviated by supplementing with Trp, and was completely negated by adding Tyr. The inhibitory effect of Thr, on the other hand, was not affected by addition of Lys or Met (which are synthesized using a common pathway with Thr), but was mitigated by supplementation with Glu, Ser, Val, Ala, or Gln. Among the antagonistic AA, Leu, Val, Trp, Tyr, and Glu were indispensable for the maximum growth rate of the ruminal bacteria under the experimental condition of supplementation of amino-N, the removal of which from a mixture of 20 protein AA caused the growth rate to decline. Removals of Ile along with Leu or Val or both, of Phe along with Trp or Tyr, and of Thr along with Glu recovered the promotion of bacterial growth rate. It was concluded that inhibitions of the bacterial growth rate caused by Ile, Phe, or Thr could be antagonized by some other AA (Leu, Val, Tyr, Trp, or Glu), and the role of these latter AA as relievers of the inhibitory effects could explain why they are indispensable for maximum growth rate of ruminal bacteria.

Phylogenetic analysis of methyl coenzyme-M reductase detected from the bovine rumen

AIMS

The object of the present study is isolation of methyl coenzyme-M reductase (MCR) genes (mcrA) from the bovine rumen fluid and determination of phylogenetical placements of the genes to investigate mechanisms of methanogenesis in the rumen from a point of view of mcrA genes.

METHODS

Genes for methanogen-specific MCR were isolated from the bovine rumen by PCR amplification. The deduced amino acid sequences were fitted to the alignments of mcrA gene products from the referred sequences.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although the deduced amino acid sequences of mcrA genes, isolated from the bovine rumen in the present study, were close to that of Methanobrevibacter ruminantium, these amino acid sequences did not fall into known clusters of MCR. The findings suggest that methanogenesis in the rumen would be partially carried out by unknown methanogens.

Detection of Proteobacteria from the rumen by PCR using methanotroph-specific primers

AIMS

To detect Proteobacteria, including methanotrophs, from the rumen fluid and the bacteria inhabiting the rumen epithelium.

METHODS AND RESULTS

Proteobacteria inhabiting the rumen were detected by PCR using methanotroph-specific primers. The detected Proteobacteria were divided into clusters A, B, and C in addition to one clone, which was distinct from the clusters and closely related to Nitrosomonas sp. The clusters A, B, and C were close to Succinivibrio dextrinosolvens, Enterobacter cloacae, and Actinobacillus minor, respectively. The clones obtained from the rumen fluid each belonged to cluster A or B. The clones obtained from the rumen epithelium belonged to cluster B or C or to Nitrosomonas sp.

CONCLUSIONS

It has been assumed that the rumen fluid and the rumen epithelium host different populations of Proteobacteria. Moreover, detection of Nitrosomonas from the rumen epithelium would indicate the possibility that the bacterium oxidizes ammonia and methane on the rumen surface.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings suggest that the rumen fluid and the epithelium support different microbial populations, which would play specific roles in rumen function. Future study should focus on the relationship between these communities and physiological functions in the rumen.

Stimulatory and inhibitory effects of protein amino acids on growth rate and efficiency of mixed ruminal bacteria

Mixed ruminal bacteria were incubated in vitro with glucose, xylose, cellobiose, and various protein amino acids replaced isonitrogenously with 25% (i.e., 25 mg of N/L) of ammonia-N, to determine the growth rate and the amount of sugar consumed in the exponential growth phase. The growth rate and efficiency (grams of bacteria per gram of sugars) increased by 46 and 15%, respectively, when a mixture of 20 amino acids was added. On the other hand, neither growth rate nor efficiency increased when any one of these amino acids was added singly, except for Glu and Gln, each of which produced significant but small improvements. The stimulatory effect of the combined amino acids on bacterial growth declined when each of Leu, Trp, Tyr, Glu, Met, Phe, and Val was removed from the original group of 20. When a mixture of only these seven amino acids was used as a supplement, their stimulatory effects on growth rate and efficiency were only 21 and 25%, respectively, of the effects that the mixture of 20 amino acids showed. The effects increased to 76 and 72% on growth rate and efficiency, respectively, when Gly, Cys, and His were supplied in addition to the seven amino acids. The growth rate and efficiency of the ruminal bacteria were inhibited by an addition of each of Ile, Thr, Cys, Phe, Leu, Lys, or Val to ammonia-N, and the effects of the first five of these amino acids were highly significant. Isoleucine, threonine, and phenylalanine were each inhibitory even at a low concentration (1 mg of NL), while cysteine and leucine showed inhibitory effects at higher concentrations (more than 10 mg of N/L). A higher growth rate of the ruminal bacteria when supplemented with amino acid mixtures was accompanied with a higher growth efficiency, which was attributable to a relatively smaller proportion of energy expended on maintenance according to the Pirt derivation.

Impact of boost irradiation with surgically placed radiopaque clips on local control in breast-conserving therapy

BACKGROUND

The purpose of this study was to determine whether boost irradiation relying on radiopaque clips placed surgically around the resected margin of breast cancer contributes to increasing the local control rate in patients with close or positive margins in breast-conserving therapy (BCT).

METHODS

Among 837 patients with breast cancer who underwent BCT between November 1987 and December 1998, 181 patients with close or positive surgical margins received boost irradiation following conventional tangential whole breast irradiation. Since 1994, four radiopaque clips were surgically placed around the resected margin of the breast cancer in 155 patients treated with wide excision. The four clips were clearly and accurately identified with a CT-simulator (CT-S). The boost irradiation field was automatically determined with a safety margin of 3 cm according to one-to-one correspondence of radiopaque clips to pathologically close or positive surgical margins. In the remaining 26 patients treated before 1994, the boost irradiation field was determined according to the skin tattoo of the primary tumor.

RESULTS

The median follow-up period of the 155 patients receiving the radiopaque clips was 42 months (range: 19 to 78), and that of the 26 patients without the clips was 87 months. Local recurrence was observed in two of the 155 patients who underwent boost irradiation using the radiopaque clips 39 and 54 months after the surgery, while 4 of the 26 patients developed local recurrence 14, 23, 51, and 76 months after BCT. In three of the four patients without the clips developing local recurrences, local recurrences were observed at the margin of the boost irradiation field. The 5-year local recurrence-free survival rate of patients who received boost irradiation with the radiopaque clips was 97%, and that of patients without the clips was 88%. The difference of local recurrence-free survival rates between the patients with and without the clips was significant (p<0.05).

CONCLUSION

Surgically placed radiopaque clips appear to be useful for determining adequate boost field in the BCT using the CT-S and help increase the local control rate.

A case of allergic reaction to surgical metal clips inserted for postoperative boost irradiation in a patient undergoing breast-conserving therapy

We report a case of a 28-year-old woman with right-sided breast cancer. The patient had been treated for atopic dermatitis since her infancy. She underwent breast-conserving surgery (BCS) in July 1998, and three titanium clips were placed at the margin of the excision cavity at the time of surgery. Two months after surgery, the patient exhibited a rapid exacerbation of atopic dermatitis. Various drugs were suspected to be the cause of the allergic reaction, but the results of a bi-digital O-ring test (BDORT) suggested an allergic reaction to titanium clips. In August 1999, the patient underwent a second operation to remove the titanium clips under local anesthesia. Allergy to surgical titanium clips is a rare complication, but in patients with a history of severe allergic diseases, a preoperative immunologic examination should be performed and the patient's history of metal allergy should be investigated.

Meningeal carcinomatosis in patients with breast cancer: report of 8 patients

BACKGROUND

Meningeal carcinomatosis (MC) is an uncommon but aggressive complication of advanced breast cancer with a recently increasing incidence. Although the prognosis is extremely poor for MC patients, early diagnosis and appropriate treatment are important.

SUBJECTS AND METHODS

We reviewed 8 cases of MC from breast cancer at Kyoto University Hospital from 1990 to 1999. The median age was 51.5 years. All patients had widespread systemic metastases when diagnosed with MC. clinical symptoms were categorized into 3 groups: cranial nerve symptoms, spinal nerve symptoms, and other symptoms. Imaging studies were positive for MC in only 4 patients. Initial CSF cytology studies were positive in 4 patients, and repeated CSF cytology yielded positive results in the remaining 4 patients. Thus the median interval between the onset of any clinical symptom of MC and the initiation of treatment was 22.5 days (range 7 to 120 days ). All patients received whole brain radiotherapy (WBRT). Four patients were given intrathecal chemotherapy and/or intrathecal immunotherapy in addition to WBRT.

RESULTS

Improvement of cranial nerve symptoms, spinal nerve symptoms, and other symptoms were observed in 3/5, 1/3, and 5/7 patients, respectively. Patients with cranial nerve symptoms who started WBRT within 29 days of the onset of the symptoms showed at least partial recovery whereas patients who started WBRT later showed no recovery. The median survival was 123 days (53 to 310 days). MC was the direct cause of death in 1 of 8 patients.

CONCLUSION

When MC is clinically suspected, neither a negative imaging study nor a single negative CSF cytology can rule out MC. Prompt initiation of WBRT with or without intrathecal chemotherapy may be important for recovery from cranial nerve symptoms.

Results of breast-conserving therapy for ductal carcinoma in situ: the Kyoto University experiences

BACKGROUND

The purpose of this study was to evaluate the results of breast-conserving therapy (BCT), defined as the combination of breast-conserving surgery with axillary dissection and definitive radiation therapy for ductal carcinoma in situ (DCIS).

METHODS

Between November 1987 and March 1998, 33 patients with DCIS undergoing BCT at our hospital were examined. The mean age was 48. All patients underwent quadrantectomy or wide excision as well as axillary dissection. Radiation therapy consisted of 50 Gy to the ipsilateral whole breast. Boost irradiation of 10 Gy was given to 15 patients with close or positive margins. Nearly all patients received adjuvant chemotherapy with 5-fluorouracil or its derivatives and adjuvant endocrine therapy with tamoxifen for 2 years.

RESULTS

The minimum and median follow-up periods were 32 and 80 months, respectively. All patients but one were followed. Only one patient had a non-invasive local recurrence, 23 months after her operation. This patient was salvaged with simple mastectomy. Her prognostic index score was 8. The five-year local control rate was 97%. No serious acute or late complications were noted.

CONCLUSION

The results of this retrospective study substantiate favorable data and appear to confirm the efficacy and reasonable local recurrence rate of BCT for the treatment of DCIS.

Determination of optimal radiation energy for different breast sizes using CT-simulator [correction of simulatior] in tangential breast irradiation

BACKGROUND

The purpose of this study is to determine and recommend the optimal radiation source according to breast size for tangential irradiation in breast conserving therapy.

METHODS

Twenty-eight patients treated at our department from January 1994 to January 1996 were studied. The dose distribution within the irradiated breast was calculated using a (60)Co-gamma ray and 6 MV-X ray. Then we compared 3-D dose distributions of the (60)Co-gamma ray and 6 MV-X ray in different-sized breasts. Three parameters (breast volume, chest wall separation, and breast height) were adopted as representative of breast size. We also examined correlations among the three parameters.

RESULTS

When the breast size was large (breast volume >400 cm(3), chest wall separation > 19.5 cm, or breast height > 6.5 cm), the average volume of normal tissue which received more than 110% of the isocenter dose ("hot spot") was significantly greater with the (60)Co-gamma ray than with the 6 MV-X ray (p < 0.05). A similar result was obtained with regard to hot spots in the clinical target volume. The cold area that received less than 95% of the isocenter dose was greater using a 6 MV-X ray when the breast size was small (breast volume <200 cm(3), chest wall separation <17.5 cm, or breast height <5.0 cm). However, the difference was not significant. There was a significant correlation between breast volume and chest wall separation (r =0.849, p <0.001). Breast volume and breast height were also significantly correlated (r =0.813, p <0.001).

CONCLUSIONS

Since breast volume and shape are different in each patient, the optimal energy should be selected for each case to obtain uniform dose distribution in breast-conserving therapy. Chest wall separation or breast height, which are measurable without a 3-D planning system, can substitute for breast volume as parameters for breast size. We recommend that the (60)Co-gamma ray not be used for treating large breasts, those with chest wall separation > or =19.5 cm or breast height > or =6.5 cm.

Evaluation of glass microspheres for intra-arterial radiotherapy in animal kidneys

PURPOSE

To evaluate the histologic distribution of nonradioactive microspheres when intra-arterially infused into normal kidneys, and to evaluate the histologic changes after the infusion.

MATERIALS AND METHODS

The glass microspheres were SiO2 microspheres with a smooth spherical shape measuring 20-30 micrometers in diameter with a specific gravity of 2.2 g/cm3. After the microspheres were mixed with contrast medium, they were infused into the renal artery. Twelve rabbits were sacrificed at 1 day, 3 days, 1 week, and 8 weeks after the treatment, respectively. The specimen was fixed with 10% buffered formalin, specially embedded in methyl methacrylate (MMA) resin and was stained by hematoxylin-eosin. The distribution of the microspheres in the kidney was analyzed microscopically, and histologic changes were also evaluated.

RESULTS

The microspheres were found in arterioles whose diameters were about 20-30 micrometers, within normal kidneys. All vessels containing microspheres were confined to arterioles or arteries. No migration of microspheres was detected in the normal lung or the contralateral kidney. Severe ischemic changes were observed in kidneys, developing within 8 weeks of the infusion.

CONCLUSION

Glass microspheres seemed to be a useful embolic material for intra-arterial radiation therapy.