Clinicopathological studies of odontoma in 47 patients

A 14-year retrospective study was performed on 47 odontomas from the files of the 1st Department of Oral and Maxillofacial Surgery at Nihon University School of Dentistry. Fifty-seven percent of the patients were male and 42.6% were female. The age distribution was 8 to 48 years with a mean age of 22 +/- 9.0 years. There were no particular symptoms associated with the odontomas, and 63.8% of our patients had no symptoms. However, 12 patients complained of swelling and 9 of pain. The tumor was found in the maxilla in 42.6% and in the mandible in 57.4%. According to the WHO histological type classification, 53.2% of the tumors were classified as compound odontoma and 46.8% as complex odontoma. The size of the tumor ranged from 5 mm to 42 mm in diameter. The average complex odontoma was much bigger than the average compound odontoma. Ghost cells were found 11 cases in our series. In addition, odontogenic epithelium was found in 16 cases. Twenty seven patients had impacted teeth in association with odontoma and 24 of the 27 teeth were removed at the time of surgical enucleation of the tumor, while 3 cases were treated by orthodontically assisted eruption. There was no recurrence in any of the studied cases.

Rapid progression of pituitary hyperplasia in humans with primary hypothyroidism: demonstration with MR imaging

PURPOSE

To use magnetic resonance (MR) imaging to evaluate the morphologic changes of the pituitary gland during the development of hypothyroidism.

MATERIALS AND METHODS

Fourteen patients who had undergone thyroidectomy were evaluated before radioactive iodine 131 therapy. In each patient, MR imaging and measurement of serum hormone levels were performed twice: 5 weeks before 131I treatment as the "euthyroid state" with thyroid hormone supplementation and on the day of 131I treatment as the "hypothyroid state" after a 3-week depletion of thyroid hormone supplements. Nine healthy volunteers also underwent MR imaging twice at an interval of 5 weeks. Pituitary volume and the relative signal intensity ratio of the anterior pituitary to the pons were measured. The shape and signal intensity of the pituitary gland were also visually assessed. The paired Student t test was used to evaluate the significance of the data. A P value less than .05 indicated a statistically significant difference.

RESULTS

The patients had significantly larger pituitary volume in the hypothyroid state than in the euthyroid state both quantitatively (P < .001) and visually. No significant differences were found in the relative signal intensity ratios of the anterior pituitary to the pons. In healthy volunteers, no significant differences in pituitary volumes or signal intensity were found between the two MR images.

CONCLUSION

Rapid progression of hyperplasia of the anterior pituitary may occur with acute development of hypothyroidism.

Relapsing-remitting multiple sclerosis: longitudinal analysis of MR images--lack of correlation between changes in T2 lesion volume and clinical findings

PURPOSE

To determine the relationship between T2 lesion volume and either disability measurements or change in T2 lesion volume over time in multiple sclerosis (MS).

MATERIALS AND METHODS

Eighteen patients (age range, 26-53 years) with clinically proved relapsing-remitting MS were examined every 6 months for over 2 years. Three-millimeter-thick contiguous images of the whole brain were obtained. T2 lesion volume was calculated with a highly reproducible volumetric computer method.

RESULTS

A substantial annual increase in T2 lesion volume, with a median annual increase of approximately 8%, was demonstrated. However, there was no significant correlation between absolute T2 lesion volume and either the absolute expanded disability status scale (EDSS) grade (P = .32) or the absolute ambulation index (AI) (P = .20). In addition, no significant correlation between change in T2 lesion volume and change in EDSS grade (P = .42) or AI (P = .37) was found. There was no significant correlation between T2 lesion volume and duration of disease (P = .08).

CONCLUSION

There is no significant correlation between T2 lesion volume and standardized disability measurements despite a substantial increase in T2 lesion volume over time. Patients have an increase in total T2 lesion volume in the brain regardless of their clinical status or disability measurements. T2 lesion volumes as outcomes in therapeutic clinical trials on MS should be viewed as secondary outcomes rather than as surrogate markers of clinical responses.

Serial analysis of magnetization-transfer histograms and Expanded Disability Status Scale scores in patients with relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

Magnetization transfer ratio histogram peak height (MTR-HPH) has been shown to correlate with macroscopic and microscopic brain disease in patients with multiple sclerosis (MS). We studied the changes in MTR-HPH and in Kurtzke's Expanded Disability Status Scale (EDSS) scores over time in a group of patients with relapsing-remitting MS.

METHODS

Twenty adult patients with relapsing-remitting MS (four men and 16 women) were followed up for a period of 334 to 1313 days. In all, 86 MR imaging studies of the brain were obtained, and MTR-HPH was calculated for each MR examination by using a semiautomated technique. Changes in MTR-HPH were compared between patients over the study's duration. A neurologist specialized in the care of MS patients assessed the EDSS score for each patient as a measure of clinical disability.

RESULTS

Serial MR data showed a subtle but significant decline in MTR-HPH with time. No significant changes in EDSS scores were noted over the same period.

CONCLUSION

Patients with relapsing-remitting MS have a significant progressive decline in normalized MTR-HPH, which is independent of EDSS score. MTR-HPH measurements can be used to monitor subclinical disease in patients with relapsing-remitting MS over a short time frame of 1 to 4 years. This parameter might be applied in future therapeutic trials to assess its usefulness.

[A surgically treated case of giant pseudoaneurysm arising as a complication following carotid endarterectomy]

We reported a case of giant pseudoaneurysm (PA) originating at the left extracranial internal carotid artery after carotid endarterectomy (CEA). A 60-year-old man underwent CEA for severe stenosis of the left internal carotid artery. A day after the operation, a left cervical painful and pulsatile mass beneath the operative scar was noticed. Soon after that, the patient showed dyspnea, and intratracheal intubation was carried out. 6 days after CEA, a painful swelling reoccurred. A left carotid angiogram visualized a 5 x 5 cm sized PA in the region of the left carotid bifurcation and demonstrated patency of the two major carotid branches. After a balloon catheter had been inserted and inflated at the carotid bifurcation, the patient underwent a second operation. The bleeding from arteriotomy was well controlled by the inflated balloon catheter at the carotid bifurcation. The continuous SURGILENE suture appeared to be disrupted and a saccular PA was found to have arisen from a defect on the lateral surface of the carotid bifurcation. The suture was completely removed and arteriotomy was closed with a continuous SURGILENE suture again and some single sutures were added. A PA arising as a complication following CEA is rare, but the possibility of PA after CEA should be considered in any patient presenting with a painful or/and pulsatile mass in the neck at any time interval following the operation. Angiography at the early post-op stage is necessary to rule out the various complications after CEA. To control the bleeding, the balloon catheter was thought to be very useful.

Allelic loss at 1p34, 13q12, 17p13.3, and 17q21.1 correlates with poor postoperative prognosis in breast cancer

Allelic losses of tumor suppressor genes (TSGs), or the chromosomal regions harboring them, in tumor DNA may become useful postoperative prognostic indicators. To examine whether specific allelic losses might correlate with postoperative survival in a 5-year prospective follow-up, we tested tumors from a cohort of 264 breast cancer patients for allelic losses of 18 microsatellite markers representing either a known TSG or a region where genetic alterations are frequent in breast tumors. Patients whose tumors had lost an allele at 1p34, 13q12, 17p13.3, or 17q21.1 had significantly higher risks of postoperative mortality than those whose tumors retained both alleles at those loci (at 1p34, a 5-year mortality rate of 29% among patients with losses vs. 7% with retentions, P = 0. 0008; at 13q12, 31% vs. 10%, P = 0.0062; at 17p13.3, 24% vs. 13%, P = 0.026; and at 17q21.1, 31% vs. 13%, P = 0.0047). Furthermore, combined losses at 13q12 and 17p13.3 increased the predicted postoperative mortality risks by a factor of 9.6 (5-year mortality rate of 42% vs. 5% with retentions, P = 0.0001), and combined losses at 1p34 and 17p13.3 raised the predicted postoperative mortality risks by a factor of 8.6 (27% vs. 3%, P = 0.0064). We conclude that allelic losses at these loci can serve as negative prognostic indicators to guide postoperative management of patients. Genes Chromosomes Cancer 26:134-141, 1999.

Proposed classification of nonatherosclerotic cerebral fusiform and dissecting aneurysms

OBJECTIVE

The aim of this study is to classify nonatherosclerotic aneurysms unrelated to the branching zones (including fusiform aneurysms and dissecting aneurysms).

METHODS

Damage to the internal elastic lamina (IEL) is often an associated factor in the pathogenesis of aneurysm formation. In this study, 85 nonatherosclerotic aneurysms arising from an arterial trunk unrelated to the branching zones were classified into four different types, based on the lesional patterns of the IEL and the state of the intima. Type 1 corresponded to classic dissecting aneurysms, the pathogenesis of which was characterized by acute widespread disruption of the IEL without intimal thickening. Patients with Type 1 aneurysms had an ominous clinical course, and many presented with sudden subarachnoid hemorrhage with frequent rebleeding. Type 2 aneurysms were segmental ectasias, which had an extended and/or fragmented IEL with intimal thickening. Weakness of the arterial wall caused by the damaged IEL was assumed to be compensated by the intimal thickening. The luminal surface of the thickened intima was smooth without thrombus formation. The patients with Type 2 aneurysms had a placid clinical course. Type 3 aneurysms were dolichoectatic dissecting aneurysms, pathologically characterized by fragmentation of the IEL, multiple dissections of thickened intima, and organized thrombus in the lumen. Most of them were symptomatic and progressively enlarged over time. Type 4 aneurysms were saccular aneurysms unrelated to the branching zones. They arose in areas with minimally disrupted IEL without intimal thickening, and there was a risk of rupture.

CONCLUSION

There was a strong relationship between the pathological features of the aneurysms and their clinical courses. This classification may provide a rationale for modes of treatment.

DNA replication errors produced by the replicative apparatus of Escherichia coli

It has been hard to detect forward mutations generated during DNA synthesis in vitro by replicative DNA polymerases, because of their extremely high fidelity and a high background level of pre-existing mutations in the single-stranded template DNA used. Using the oriC plasmid DNA replication in vitro system and the rpsL forward mutation assay, we examined the fidelity of DNA replication catalyzed by the replicative apparatus of Escherichia coli. Upon DNA synthesis by the fully reconstituted system, the frequency of rpsL-mutations in the product DNA was increased to 1.9x10(-4), 50-fold higher than the background level of the template DNA. Among the mutations generated in vitro, single-base frameshifts predominated and occurred with a pattern similar to those induced in mismatch-repair deficient E. coli cells, indicating that the major replication error was slippage at runs of the same nucleotide. Large deletions and other structural alterations of DNA appeared to be induced also during the action of the replicative apparatus.

Interactions between cytoskeletal components during myoplasm rearrangement in ascidian eggs

Ooplasmic segregation in ascidian eggs consists of two phases of cytoplasmic movement, the first phase is mediated by the microfilament system and the second is mediated by the microtubule system. Recently, two novel proteins, p58 and myoplasmin-C1, which are localized to the myoplasm, were suggested to have important roles in muscle differentiation. In order to analyze the molecular mechanisms underlying ooplasmic segregation, the interactions between actin, tubulin, p58 and myoplasmin-C1 were examined. During the first segregation, microtubule meshwork in the unfertilized egg disappeared. At the second segregation, a novel structure of the microtubules that extended from the sperm aster and localized in the cortical region of the myoplasm was found. Moreover, uniform distribution of the cortical actin filament was observed at the second segregation. During the course of myoplasm rearrangement, p58 and myoplasmin-C1 are colocalized and can form a molecular complex in vitro. This complex of p58 and myoplasmin-C1 is a good candidate for a cytoskeletal component of the myoplasm, and is likely to be involved in the correct distribution of cytoplasmic determinants.

Clinicopathologic analysis of BRCA1- or BRCA2-associated hereditary breast carcinoma in Japanese women

BACKGROUND

The purpose of this investigation was to elucidate the clinicopathologic characteristics of BRCA1- and BRCA2-associated hereditary breast carcinomas (HBCs) in Japanese women.

METHODS

Various clinicopathologic characteristics of HBCs arising in patients with BRCA1 or BRCA2 germline mutations were compared with those of the control group (sporadic breast carcinomas).

RESULTS

The mean age at the time of diagnosis of BRCA1-associated HBCs and that of BRCA2-associated HBCs (44 years for both) were significantly younger than that of the control group (54 years) and the incidence of bilateral tumors was significantly higher in the BRCA1-associated HBCs (32%) and BRCA2-associated HBCs (29%) than in the control group (6%). BRCA1-associated HBCs showed a tendency (P = 0.06) toward an increase in solid-tubular type tumors and a significant increase in histologic grade 3 tumors (P < 0.01) and lymphatic invasion positive tumors (P < 0.05) compared with the control group. BRCA1-associated HBCs were significantly more estrogen receptor negative (P < 0.01), c-erb B-2 negative (P < 0.05), and p53 positive (P < 0.01), and they also showed a significant increase in MIB-1 staining grades (P < 0.01) as well as microvessel counts (P < 0.05) compared with the control group. However, there was no significant difference in these parameters between the BRCA2-associated HBCs and the control group.

CONCLUSIONS

BRCA1-associated HBCs in Japanese women have biologically aggressive phenotypes. However, BRCA2-associated HBCs are without distinctive clinicopathologic features compared with sporadic breast carcinomas.

Hyperinsulinaemic hypoglycaemia associated with persistent hyperammonaemia

Two cases of hyperinsulinaemic hypoglycaemia associated with persistent hyperammonaemia in unrelated infants of 7 days and 4 months of age are reported. Blood ammonia levels were 100-300 micromol/l (normal values <40 micromol/l). The hyperammonaemia was asymptomatic and not associated with any of the abnormalities of amino acids or organic acids observed in urea cycle enzyme defects. Orotic aciduria was normal. The hyperammonaemia was not influenced by the levels of blood glucose nor by subtotal pancreatectomy. On admission blood glucose was ca. 1.2 mmol/l (21.6 mg/dl) corresponding to blood insulin levels of 35 and 22 mU/l respectively in both infants. Continuous intravenous glucose perfusion was necessary to prevent hypoglycaemia. Furthermore 2-oxoglutaric acid in urine was increased in the second infant to 3.15 mg/mg creatinine (normal 0.41+/-0.12). This may point to mutations in the glutamate dehydrogenase gene.

CONCLUSION

2-Oxoglutaric aciduria may be an important clue to the diagnose in this syndrome.

Differences between relapsing-remitting and chronic progressive multiple sclerosis as determined with quantitative MR imaging

PURPOSE

To investigate the cross-sectional relationships among multiple quantitative brain magnetic resonance (MR) imaging measurements in patients with relapsing-remitting versus chronic progressive multiple sclerosis (MS).

MATERIALS AND METHODS

Thirty-eight patients with MS (relapsing-remitting, 26, chronic progressive, 12) were examined. Lesion volume on T2-weighted MR images, contrast material-enhancing lesion volume, percentage of brain parenchymal volume (brain volume/[brain volume + cerebrospinal fluid volume), and magnetization transfer ratio histogram peak height for the whole brain were calculated.

RESULTS

Significant negative correlation was noted between volume on T2-weighted images and magnetization transfer ratio histogram peak height for both the relapsing-remitting and chronic progressive groups (P < .001 for both). A positive correlation was demonstrated for lesion volume on T2-weighted images and enhancing lesion volume in the relapsing-remitting group (P < .01) but not in the chronic progressive group. Negative correlations were demonstrated for enhancing lesion volume and magnetization transfer ratio histogram peak height (P = .02), for Expanded Disability Status Scale score and magnetization transfer histogram peak height (P = .02), and for Expanded Disability Status Scale score and percentage of brain parenchymal volume in the relapsing-remitting group (P = .004) but not in the chronic progressive group.

CONCLUSION

The cross-sectional relationships among multiple quantitative brain MR imaging measurements are different between relapsing-remitting and chronic progressive MS.

A task-specific evaluation of three-dimensional image interpolation techniques

Image interpolation is an important operation that is widely used in medical imaging, image processing, and computer graphics. A variety of interpolation methods are available in the literature. However, their systematic evaluation is lacking. In a previous paper, we presented a framework for the task-independent comparison of interpolation methods based on certain image-derived figures of merit using a variety of medical image data pertaining to different parts of the human body taken from different modalities. In this work, we present an objective task-specific framework for evaluating interpolation techniques. The task considered is how the interpolation methods influence the accuracy of quantification of the total volume of lesions in the brain of multiple sclerosis (MS) patients. Sixty lesion-detection experiments coming from ten patient studies, two subsampling techniques and the original data, and three interpolation methods are carried out, along with a statistical analysis of the results.

Expression of receptors for basic fibroblast growth factor on human periodontal ligament cells

Basic fibroblast growth factor (FGF-2; bFGF) is a major mitogen for connective tissue cells, and participates in the healing process. It has already been reported that FGF-2 could be applicable to enhance periodontal regeneration. In the present study, we examined FGF receptor (FGFR) expression on human periodontal ligament (PDL) cells. The binding of [125I]-labeled FGF-2 to human PDL cells was studied by radioreceptor assay. The binding of [125I]-FGF-2 to PDL cells reached a plateau after 2.5 h incubation at 4 degrees C and was inhibited by the addition of unlabeled FGF-2 and acidic FGF (FGF-1; aFGF), but not insulin-like growth factor-I, platelet-derived growth factor and transforming growth factor-beta 1. Scatchard analysis revealed the presence of approximately 1.0 x 10(5) FGF-2 binding sites per cell with an apparent Kd of 1.2 x 10(-10) M. Interestingly, the binding of [125I]-FGF-2 on PDL cells reached its maximum at d 6 of the culture and then gradually decreased. Scatchard analysis also demonstrated that the number of FGFRs on a PDL cell was altered during the course of the culture, while the affinity between FGF-2 and its receptor was not. The responsiveness of PDL cells to FGF-2, which was monitored by the inhibitory effect on alkaline phosphatase activity, was reduced in proportion to the decrease in the number of FGFRs on the PDL cells. The present study suggests that PDL cells alter the responsiveness to FGF-2 during the course of the culture by changing the density of its receptor, and that the density of FGFR expression might be a marker of the cytodifferentiation of PDL cells into mineralized tissue forming cells.

A new technique of laparoscopic obturator hernia repair: report of a case

An 84-year-old woman presented with ileus. Ultrasonography, a computed tomography scan, and small bowel contrast examination showed a Richter-type hernia in her left obturator orifice. Under general anesthesia, laparoscopic surgery with low-pressure (4mmHg) pneumoperitoneum was carried out using a peritoneal needle retractor, and a reduction of the strangulated intestinal loop was thus achieved. Because the hernial opening measured 5mm in diameter, it could be closed with four pieces of End-Universal stapler without polypropylene mesh. The ischemic ileum was resected, and the bowel was anastomosed extracorporeally with a minimal skin incision. She was ambulant on the first postoperative day, and her postoperative course was good. Obturator hernias are rare, but when a definitive diagnosis is made in such elderly patients, laparoscopic repair using the peritoneal needle retractor is recommended for minimally invasive surgery. We recommend doing the repair with an End-Universal stapler, since this procedure is more simple and useful for preventing infection than using polypropylene mesh in such a strangulated case.

Retrotransposal integration of mobile genetic elements in human diseases

Approximately one-third of the mammalian genome is composed of highly repeated DNA sequences, of which the two major families, the long and short inter-spersed nucleotide elements (LINEs and SINEs), are represented in humans by L1 and Alu elements respectively. Both 'types of element are considered to be retrotransposable and to play significant roles in genomic function and evolution. The majority of inserted elements are truncated and often rearranged relative to full-length elements; usually, such retrotransposed sequences are flanked by target-site duplications of various lengths and contain 3' polyA tracts, common characteristics of retrotransposal integration. Retrotransposal integrations of Alu and L1 sequences into biologically important genes appear to play significant roles in some human diseases. Most of the inserted sequences that cause human diseases seem to belong to one or a few subsets of each type of retrotransposon, suggesting that only a few active elements can function as templates for retrotransposition. Integrations observed in oncogenes and in tumor suppressor genes may participate in carcinogenesis by altering the activity of the affected genes. The exact mechanism of these events is unclear; however, retrotransposal integration may be a general mechanism of mutation in humans.

High proportion of missense mutations of the BRCA1 and BRCA2 genes in Japanese breast cancer families

Mutations in either of two recently identified genes, BRCA1 and BRCA2, are thought to be responsible for approximately two-thirds of all cases of autosomal-dominantly inherited breast cancer. To examine the nature and frequency of BRCA1 and BRCA2 mutations in Japanese families exhibiting a high incidence of breast cancer, we screened 78 unrelated families in this category for mutations of these two genes. Examining the entire coding sequences as well as exon-intron boundaries of both genes by polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) and multiplex-SSCP analysis, we identified possible disease-causing alterations in BRCA1 among affected members of 15 families and in BRCA2 in another 14 families. In 15 of those 29 families, the affected individuals carried missense mutations, although most germline mutations reported worldwide have been deletions or nonsense mutations. Our results, indicating that missense mutations of BRCA1 and BRCA2 tend to predominate over frameshifts or nonsense mutations in Japanese breast cancer families, will contribute significantly to an understanding of mammary tumorigenesis in Japan, and will be of vital importance for future genetic testing.

Correlation of volumetric magnetization transfer imaging with clinical data in MS

We examined the relations between quantitative volumetric estimates of cerebral lesion load based on magnetization transfer imaging (MTI), clinical data, and measures of neuropsychological function in 44 patients with clinically diagnosed MS. In this population we assessed the correlation between several volumetric MTI measures, measures of neurologic function (Kurtzke Expanded Disability Status Scale and Ambulation Index), and disease duration using Spearman's correlation coefficient. Patients were classified on the basis of neuropsychological test performance as severely impaired, moderately impaired, and normal. We assessed differences between these groups with respect to MTI results using the Kruskal-Wallis test. MTI measures corrected for brain volume were found to correlate with disease duration (p < 0.01) and showed suggestive correlations with measures of neurologic impairment (p < 0.05). Individual neuropsychological tests correlated with MTI measures corrected and not corrected for brain volume (p < 0.001). An MTI measure not corrected for brain volume differed (p < 0.05) between severely impaired, moderately impaired, and normal patients. These preliminary results suggest that volumetric MTI analysis provides new measures that reflect more accurately the global lesion load in the brain of MS patients, and they may serve as a method to study the natural course of the disease and as an outcome measure to evaluate the effect of drugs.

Isolated U-fiber involvement in MS: preliminary observations

We studied the frequency and location of isolated U-fiber involvement in MS and correlated these findings exploratively with physical disability and neuropsychological impairment. Fifty-three MS patients were examined. Three-millimeter-thick, fast spin-echo T2-weighted MR images and spin-echo postgadolinium T1-weighted images were obtained. Computer software that which had been validated previously for quantitation of MS lesions was used to detect lesions on the T2-weighted images. The Expanded Disability Status Scale (EDSS), Ambulation Index (AI), and a battery of neurocognitive tests were performed on each patient. Forty-two arcuate hyperintensities along the U-fiber were detected by the software in 28 patients (53%). Twenty-seven lesions (64.3%) were seen in the frontal lobe, eight (19.0%) in the temporal lobe, three (7.1%) in the parietal lobe, three (7.1%) in the occipital lobe, and one (2.4%) in both frontal and parietal lobes. Four lesions (9.5%) showed gadolinium enhancement. Seventeen lesions (40%) were hypointense on the T1-weighted images. Scores of three of the 11 neuropsychological tests reflecting performance in executive control and memory were significantly different at least at the p = 0.05 level between the eight patients with multiple, isolated U-fiber lesions and the 45 patients without any or with only a single U-fiber lesion. No significant difference was noted for EDSS or AI. Isolated U-fiber involvement is an underappreciated MR finding in MS. Our preliminary hypothesis is that U-fiber lesions may contribute to neuropsychological impairment, although our observation requires confirmation.

Multiple possible sites of BRCA2 interacting with DNA repair protein RAD51

To investigate the biological consequences of aberrant BRCA2 protein during mammary carcinogenesis, we attempted to identify proteins that normally interact with BRCA2. By using a yeast two-hybrid system with a hybrid protein that contained residues 639-1,508 of BRCA2 protein fused to the GAL4 DNA-binding domain, we isolated five independent cDNA clones that encoded parts of RAD51 protein, a human homolog of bacterial RecA. In vitro experiments using anti-RAD51 antibody confirmed interaction of BRCA2 with RAD51. The RAD51-binding region of BRCA2 detected in the present study was distinct from the region reported recently. Further studies using smaller portions of BRCA2 defined at least two additional RAD51-binding domains, residues 982-1,066 and 1,139-1,266. Our results suggest that BRCA2 can interact with RAD51 through multiple sites of BRCA2 and that control of mitotic and meiotic recombination and/or of genomic integrity through binding to RAD51 may be a crucial mechanism by which BRCA2 suppresses abnormal proliferation of mammary cells.

Multiplex mutation screening of the BRCA1 gene in 1000 Japanese breast cancers

To detect BRCA1 mutations in Japanese breast cancer patients, we screened 1,000 unselected primary cancers for mutations in exon 11, which accounts for 61% of the entire BRCA1 coding sequence. Using a method based on multiplex single-strand conformational polymorphism (SSCP) analysis of multiple restriction fragments generated by restriction-enzyme digestion of amplified DNA, we identified eight mutations. All eight were germline mutations; four of them were non-sense mutations or small deletions resulting in premature stop codons, and the other four were missense mutations. The Japanese carriers of these mutant BRCA1 alleles had developed breast cancers at ages ranging from 45 to 62, five of them bilaterally.

Comparison of T2 lesion volume and magnetization transfer ratio histogram analysis and of atrophy and measures of lesion burden in patients with multiple sclerosis

PURPOSE

The purpose of this study was twofold: first, to compare two different measures of lesion burden in patients with multiple sclerosis (MS), the magnetization transfer ratio (MTR) histogram and T2 lesion volume; and, second, to investigate the relationship between lesion burden and atrophy in patients with MS.

METHODS

Thirty patients with MS were examined with MR imaging, including fast spin-echo T2- and proton density-weighted sequences as well as magnetization transfer sequences. The lesion burden in each subject was quantitated by MTR histographic analysis and by a computer-based method for calculating the total volume of lesions on T2-weighted images. Additionally, the CSF volume, the brain parenchymal volume, and the percentage of brain parenchymal volume were determined in all patients by using this method and were compared with measurements in eight control subjects.

RESULTS

Significant loss of parenchymal volume was seen in patients with MS as determined by increased CSF volume and decreased percentage of brain parenchymal volume relative to that in age-matched control subjects. An inverse correlation was observed between the peak height of the MTR histogram and T2 lesion volume. T2 lesion volume corresponded positively with CSF volume and inversely with percentage of brain parenchymal volume. The peak height of the MTR histogram corresponded positively with percentage of brain parenchymal volume and inversely with CSF volume.

CONCLUSION

MS patients sustain a significant loss of parenchymal volume (atrophy), which corresponds strongly with increasing lesion burden. T2 lesion volume and peak height of the MTR histogram show good correlation, and the peak height of the MTR histogram shows a superior correlation with measures of brain atrophy as compared with measurements of T2 lesion volume, suggesting that the MTR histogram may be a better indicator of global disease burden than is T2 lesion volume.