Effects of scatter and attenuation correction on quantitative assessment of regional cerebral blood flow with SPECT

Appropriate corrections for scatter and attenuation correction are prerequisites for quantitative SPECT studies. However, in most cerebral SPECT studies, uniform attenuation in the head is assumed, and scatter is usually neglected. This study evaluated the effect of attenuation correction and scatter correction on quantitative values and image contrast.

METHODS

Studies were performed in six normal volunteers (ages 22-26 yr) following intravenous 123I-IMP administration using a rotating, dual-head gamma camera. A transmission scan was acquired with a 99mTc rod source (74 MBq) placed at the focus of a symmetrical fanbeam collimator. Data were reconstructed using two attenuation coefficient (mu) maps: quantitative mu map from the transmission scan and a uniform mu map generated by edge detection of the reconstructed images. Narrow and broad beam mu values were used with and without scatter correction, respectively. Scatter was corrected with transmission-dependent convolution subtraction and triple-energy window techniques. Quantitative rCBF images were calculated by the previously validated IMP-autoradiographic technique, and they were compared with those obtained by (15)O-water and PET. SPECT and PET images were registered to MRI studies, and rCBF values were compared in 39 ROIs selected on MRI.

RESULTS

Clear differences were observed in rCBF images between the measured and constant mu maps in the lower slices due to the airways and in the higher slices due to increased skull attenuation. However, differences were < 5% in all cerebral tissue regions, thus assumption of uniform mu introduces little bias. The scatter correction was found to increase the image contrast significantly, i.e., rCBF increased by 20%-30% in gray matter and decreased in white matter regions by 10%-20% after scatter correction, increasing gray-to-white ratio to be close to that of PET measurement. The rCBF values from the two scatter correction were not significantly different, but the triple-energy window technique suffered from increased noise. After scatter correction, rCBF values were in good agreement with those measured by PET.

CONCLUSION

This study shows little loss in accuracy results from assuming uniform mu map. However, scatter correction is required for the quantitative rCBF values and gray-to-white ratios to approach those of PET.

Recurrence of a germ cell tumor 12 years after initial treatment: a case report

Patients with testicular germ cell tumors who have disease-free remission for more than 2 years are usually considered to be cured of their disease. This report describes a case of a germ cell tumor recurring 12 years after initial diagnosis and its treatment in a 35-year-old man who developed a retroperitoneal mass adhering to the abdominal aorta with a bout of severe colic in the left flank. Although tumor markers were not elevated and histology of the biopsy specimen was initially diagnosed as adenocarcinoma, we finally concluded that the retroperitoneal tumor was teratoma developing as a recurrence of the germ cell tumor for the following reasons: (1) the histology of the specimen was similar to an epithelial component of teratoma found in the tissue resected 12 years before; (2) systemic survey failed to detect any other primary site; (3) the young age of this patient was consistent with germ cell tumor rather than adenocarcinoma; and (4) the retroperitoneum is the most frequent site of late recurrences of testicular cancer. He was treated successfully with combination chemotherapy of cisplatin, etoposide and bleomycin followed by surgery. It is important to differentiate this treatable disease from metastasis from an unknown primary, because the latter responds poorly to therapy and survival is usually short.

[Balloon-occluded arterial infusion chemotherapy in treatment of the patients with locally recurrent carcinoma of the cervix who previously received radiation therapy]

Nine patients with locally recurrent carcinoma of the cervix were treated with balloon-occluded arterial infusion chemotherapy (BOAI) in order to secure high concentrations of antitumor agents. All the patients had previously received radiation therapy for squamous cell carcinoma of the cervix. Recurrence was diagnosed by cytology and/or biopsy, or CT. Either cisplatin 100 mg/body and doxorubicin hydrochloride 40 mg/body or cisplatin 50-100 mg/body and pirarubicin 40-60 mg/body were infused after the bilateral internal iliac arteries had been occluded using balloon catheters. As the largest diameter of the tumors on CT increased, the mean survival after BOAI decreased. The mean survival of 4 patients with no detectable masses on CT was 45 +/- 30.7 months. In 5 patients, neurological complications, subcutaneous and/ or skin reactions of the buttock, or necrosis of the uterus developed. The neurological complications were damage to the sciatic nerve at the level of S1 or S2. Our study suggests that BOAI therapy may lead to a high complication rate in patients with locally recurrent carcinoma of the cervix who previously received radiation therapy, although long-term survival can be expected in patients with no detectable masses on CT.

Serum amyloid P component enhances induction of murine amyloidosis

Serum amyloid P component (SAP), a common component of all known types of amyloid fibrils, protects amyloid fibrils from proteolysis in vitro. It is therefore speculated to contribute to the deposition of amyloid fibrils in various types of amyloidoses. However, a role for SAP in amyloid deposition is not yet known. To investigate the relationship between SAP and amyloid deposition, we used gene targeting techniques to generate a unique strain of mice carrying a null mutation at the sap locus. The resultant SAP-deficient mice displayed no obvious phenotypic abnormalities. We asked whether experimental amyloid A (AA) amyloidosis could be induced in the SAP-deficient mice. The wild-type and SAP-deficient mice did not differ in their synthesis of serum amyloid A, the precursor protein of AA amyloid fibril, in response to acute inflammation. The induction of AA amyloidosis, however, was significantly retarded in the SAP-deficient mice relative to wild-type mice. Our experiments present, for the first time, compelling evidence that, although not essential in the deposition of AA amyloid, SAP significantly accelerates this reaction. Thus, SAP enhances the induction of murine amyloidosis and may play an important role in the pathogenesis of human amyloidoses, including Alzheimer's disease.

[Chronic renal failure and guanidino compounds]

Guanidino compounds are known as uremic toxins which increase in the blood of patients with renal failure. Guanidino succinic acid (GSA) and methyl guanidine (MG) have been intensively studied since they are toxic and are candidate markers which reflect the pathological stage of nephritis. GSA correlates well with blood urea nitrogen and therefore indicates the reduction of renal function. MG does not appear in the early stage of renal failure and abruptly increases at the stage of serious uremia. MG is produced by the oxidation of creatinine (CTN) with active oxygen. The MG/CTN ratio in the serum therefore reflects the degree of the generation of active oxygen. Accordingly, active oxygen scavengers may be useful for the treatment of uremia.

Presacral neurilemmoma mimicking degenerated subserosal uterine leiomyoma

A case of presacral neurilemmoma extending into the pelvic cavity is reported. T2-weighted MR sagittal images showed a tumor resembling subserosal uterine leiomyoma with degeneration. CT revealed features distinguishing retroperitoneal neurilemmoma from gynecological tumors. The possibility of retroperitoneal neurilemmoma should be raised when a large pelvic tumor attached to the sacrum is noted on CT or MR study.

Global dimensional complexity of multichannel EEG in mild Alzheimer's disease and age-matched cohorts

Multichannel EEG as sequence of momentary brain field maps constitutes a trajectory through K-dimensional state space (K = number of channels); the complexity of this trajectory is assessed by the nonlinear measure of global correlation dimension (Global Dimensional Complexity, GDC) with the number of electrodes as embedding dimension. We analyzed eyes-closed EEG of three age-matched subject groups: mild Alzheimer's disease (AD; n = 21), mild cognitive impairment (29) and subjective memory complaint (29). Kruskal-Wallis statistics showed an overall effect between groups. AD patients differed significantly (GDC = 4.56) from mild cognitive impairments (GDC = 4.98) and from subjective memory complaints (GDC = 4.93). GDC also had significant positive correlations with mental condition and performance (MMSE and WAIS-R scores). Thus, the dynamics of brain state development over time in mild AD differs from that in mild cognitive impairment and in subjective memory complaint cases.

[Study on risk factors for central visual field loss in advanced open angle glaucoma]

53 eyes of 53 advanced open angle glaucoma (stage 5 of Aulhorn-Greve's classification) were studied regarding the risk factors for central visual field loss by the Cox proportional hazards model. The cases of foveal threshold under 20 dB were defined as central visual field loss group (9 eyes), and the cases over 20 dB were defined as no visual field loss group (44 eyes). The following clinical factors were statistically analyzed between the two groups: gender, age, family history of glaucoma, refraction, intraocular pressure, blood pressure, visual field measured by static perimetry, optic disc, retinal nerve fiber layer, treatment, and systemic disease. Foveal threshold, mean deviation, pattern standard deviation, corrected pattern standard deviation, and retinal nerve fiber layer defect showed significant difference between the two groups, and diastolic blood pressure and diastolic blood pressure minus intraocular pressure showed a tendency to be related. From the results obtained, intraocular pressure and these other clinical factors should be considered for the management of advanced open angle glaucoma patients.

The production of tissue inhibitors of metalloproteinases (TIMPs) in megakaryopoiesis: possible role of platelet- and megakaryocyte-derived TIMPs in bone marrow fibrosis

We quantified tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in serum and plasma in normal control subjects and patients with a low or high platelet count, using one-step sandwich enzyme immunoassays. The serum levels of TIMP-1 and TIMP-2 were 101.1 +/- 13.3 ng/ml, and 82.7 +/- 26.3 ng/ml, respectively, in normal subjects. In patients with an elevated platelet count, such as in essential thrombocytosis, polycythaemia vera, and myelofibrosis, serum levels of TIMP-1 and TIMP-2 were 351.6 +/- 200.9 ng/ml and 148.9 +/- 84.0 ng/ml, respectively. Serum levels of TIMP-1 and TIMP-2 in patients with a low platelet count, such as in aplastic anaemia and idiopathic thrombocytopenic purpura, were 57.2 +/- 25.8 ng/ml and 19.7 +/- 7.68 ng/ml, respectively. The serum level of TIMP-1 was significantly correlated with the platelet count in all subjects. The correlation between the serum level of TIMP-2 and the platelet count was not as strong. The level of TIMP-1 in platelet-depleted plasma was not correlated with the platelet count. Immunohistochemical staining using monoclonal antibodies against TIMP-1 and TIMP-2 showed that megakaryocytes and platelets were positive for both TIMP-1 and TIMP-2, confirming that they are rich sources of TIMPs. TIMP-1 and TIMP-2 stimulated the proliferation of bone marrow fibroblasts, although their effect was less potent than that of TGF-beta and PDGF. Erythroleukaemia and megakaryoblastic cell lines showed the highest secretion of TIMP-1 among the leukaemia cell lines examined. There was no lineage specificity for TIMP-2 secretion. These results suggest that TIMPs released from megakaryocytes or from local platelet coagulation may be important in the development of bone marrow fibrosis.

Bactericidal action of lysozymes attached with various sizes of hydrophobic peptides to the C-terminal using genetic modification

The genetic modification of lysozyme was attempted to improve the bactericidal activity against Gram-negative bacteria E. coli. The different lengths of hydrophobic peptides were attached to the C-terminus of the hen egg white lysozyme to investigate the most effective length of the hydrophobic peptides for killing bacteria. The oligonucleotides encoding Phe-Val-Pro (H3), Phe-Phe-Val-Ala-Pro (H5) and Phe-Phe-Val-Ala-Ile-Ile-Pro (H7) were fused to the C-terminus Leu 129 of lysozyme cDNA. The reconstructed cDNAs were inserted into the yeast expression vector. The hydrophobic peptide-fused lysozymes were secreted in the yeast carrying the reconstructed cDNA. Although the hydrophobic peptide-fused lysozymes retained 75 80% lytic activity of the wild-type protein, the bactericidal action to E. coli was greatly increased with the length of hydrophobic peptides. These results suggest that the hydrophobic peptides play an important role in killing Gram-negative bacteria. To elucidate the role of catalytic domain in bactericidal action of the hydrophobic fusion lysozyme (H5-Lz), the mutant hydrophobic lysozyme (H5/E35A-Lz) whose glutamic acid was substituted with alanine at the position 35 was constructed to diminish the catalytic activity. The mutant hydrophobic lysozyme (H5/E35A-Lz) was greatly lost the bactericidal action to E. coli, suggesting that not only the length of hydrophobic peptide fused to C-terminus but also the catalytic domain is important for the bactericidal action of the hydrophobic peptide-fused lysozyme.

Structures and chromosomal localizations of the glycosylphosphatidylinositol synthesis gene PIGC and its pseudogene PIGCP1

More than 10 genes are involved in the biosynthesis of glycosylphosphatidylinositol (GPI), which anchors many mammalian cell surface proteins to the membrane. Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a somatic mutation in a GPI biosynthesis gene within the hematopoietic stem cell. The X-linked gene PIGA has been found to be mutated in all patients with PNH. This is probably because all other GPI synthesis genes are autosomal; hence two somatic mutations must occur to cause PNH, whereas one somatic mutation is sufficient to inactivate PIGA. Consistent with this notion, three other genes, PIGB, PIGF, and PIGH, are autosomal. Here we isolated a genomic clone of another GPI-synthesis gene, PIGC, and mapped it to chromosome 1q23-q25, further supporting this notion. PIGC is an intronless gene. We found an intronless pseudogene of PIGC, PIGCP1, and mapped it to chromosome 11p12-p13. The presence of a processed pseudogene is a common feature of PIGA, PIGF, and PIGC.

Requirement of the caspase-3/CPP32 protease cascade for apoptotic death following cytokine deprivation in hematopoietic cells

Hematopoietic cytokines transduce cell survival signals, which are distinct from the signals necessary for the stimulation of DNA synthesis. Recently, the Ras and phosphatidylinositol 3-kinase pathways have been shown to play important roles in preventing apoptosis in various cell types, e.g. hematopoietic cells and neuronal cells. Withdrawal of cytokine(s), in turn, results in rapid inactivation of these survival pathways and eventually leads to cell death accompanied by the hallmarks of apoptosis. However, the mechanism of cell death caused by cytokine deprivation has not been fully elucidated. In this study, we demonstrate that caspase-3/CPP32, a member of the caspase/interleukin-1beta-converting enzyme family, is activated upon interleukin (IL)-3 deprivation in IL-3-dependent cells as well as IL-2 deprivation in IL-2-dependent cells. In addition, poly(ADP-ribose) polymerase, a cellular substrate for the caspase family proteases, was degraded into apoptotic fragments in both cell lines after cytokine removal. Furthermore, inhibition of a caspase family protease by synthetic peptides suppressed apoptotic death. These results indicate that the activation of a caspase-like protease(s) is required for the progression of apoptosis following cytokine deprivation. However, readdition of IL-3 did not restore the proliferative potential of the cells that survived in the presence of the peptide inhibitor after IL-3 depletion. Therefore, cellular commitment to apoptosis appears to precede the activation of a caspase-like protease(s).

Hepatocellular carcinoma with portal vein tumor thrombus: embolization of arterioportal shunts

PURPOSE

To evaluate transcatheter arterial embolization in patients with hepatocellular carcinoma, portal vein tumor thrombus, and arterioportal shunts.

MATERIALS AND METHODS

Ten patients with hepatocellular carcinoma, portal vein tumor thrombus, and severe arterioportal shunting were identified; in these patients, portal blood flow before embolization was hepatofugal. Embolization of arterioportal shunts was performed with steel coils that were introduced through a catheter during arteriography. After embolization, changes in portal hemodynamics and clinical signs and performance status of patients were evaluated; survival rates of patients with and patients without severe arterioportal shunting were compared.

RESULTS

In all patients after embolization, angiography showed resolution of arterioportal shunting, and portography showed hepatopetal blood flow in the portal vein trunk. After embolization, performance status of five patients with initial scores of 2 or 3 improved. Ascites resolved in four patients and improved in four patients. One patient died of hepatic failure caused by rupture of esophageal varices 7 days after embolization. Median survival was 4.3 months, and the 6-month and 1-year survival rates were 45% and 12%, respectively. There were no significant differences between survival rates in patients with and patients without severe arterioportal shunting.

CONCLUSION

Transcatheter arterial embolization of arterioportal shunts is a useful treatment for improving quality of life in patients with hepatocellular carcinoma.

Intraductal papillary tumors and mucinous cystic tumors of the pancreas: clinicopathologic study of 38 cases

Clinicopathological features of 28 patients with intraductal papillary tumor (IDPT) and 10 patients with mucinous cystic tumor (MCT) of the pancreas were studied. Both IDPT and MCT showed papillary projections of the epithelium with abundant mucus secretion in the ectatic ducts or cystic spaces. The patients with IDPT comprised 19 men and 9 women with a mean age of 64.9 years. Three fourths of the IDPTs were located in the pancreatic head, and the mean tumor size was 3.5 cm. Local recurrence was observed in one patient, but none died of IDPT. In contrast, all patients with MCT were women, with a mean age of 49.4 years. None of the MCTs arose in the head, and the mean tumor size was 7.1 cm. One patient died of MCT, but all of the others survived without recurrence. Eight IDPTs and three MCTs showed invasion into the surrounding pancreatic tissue. Muconodular infiltration was mainly observed in five IDPTs and one MCTs and tubular infiltration in three IDPTs and two MCTs. A characteristic histological finding associated with the muconodular infiltration in IDPT was subepithelial "mucin droplets" that appeared to represent a change in polarity of mucus secretion. The formation of such subepithelial "mucin droplets" may be the initial step of muconodular infiltration in IDPT. Muconodular infiltration in IDPT appears different morphologically and biologically from the mucinous carcinoma subtype of conventional invasive ductal carcinoma.

Detection of Clostridium septicum hemolysin gene by polymerase chain reaction

A polymerase chain reaction (PCR) was developed for the detection of the hemolysin (alpha toxin) gene of Clostridium septicum. The PCR primers were designed from the sequence of the hemolysin gene and synthesized. A DNA fragment of 270 bp was amplified from 10 strains of C. septicum, but was not from strains of C. chauvoei, C. perfringens, C. novyi, or C. haemolyticum. When the PCR product was digested with Sau3AI, two DNA fragments of the expected 148 bp and 122 bp were recognized. The lowest detectable threshold of PCR for the hemolysin gene was 3.8 x 10(3) cells/ml. The PCR technique may be useful for rapid detection or identification of C. septicum associated with malignant edema.

Malignant lymphoma arising from chronic tuberculous empyema. A case report

We report on a case of malignant lymphoma in the chest wall, associated with chronic tuberculous empyema. CT and MR imaging showed a soft-tissue mass contiguous with the empyema and invading the chest wall. MR imaging demonstrated a difference in signal intensity between the mass and the empyema. The extent of the chest-wall lymphoma was optimally delineated on fat-suppressed contrast-enhanced MR images.

Mutations of the p53 gene as a prognostic factor in aggressive B-cell lymphoma

BACKGROUND

Mutations of the p53 gene are associated with a poor prognosis in several types of cancer. We investigated the prognostic importance of p53 mutations in patients with aggressive B-cell lymphoma.

METHODS

We examined the relation between the presence or absence of a detectable p53 mutation in lymphoma cells and the response to chemotherapy and overall survival in 102 previously untreated patients with aggressive B-cell lymphoma. Mutations of the p53 gene were identified by polymerase-chain-reaction-mediated analysis of single-strand conformation polymorphisms and by direct sequencing.

RESULTS

Of 102 cases of aggressive B-cell lymphoma, 22 (22 percent) involved p53 mutations. The rate of complete remission was significantly lower in patients with a tumor carrying a p53 mutation (6 of 22 patients, 27 percent) than in those with the wild-type p53 gene (61 of 80 patients, 76 percent) (P<0.001). Overall survival was significantly lower among patients with p53 mutations than among those with the wild-type p53 gene; the Kaplan-Meier estimates of survival at five years were 16 percent and 64 percent, respectively (P<0.001). Multivariate analysis incorporating prognostic factors from the international prognostic index demonstrated that p53 mutations had independent effects on the rates of complete remission and survival. When we categorized patients according to the international prognostic index, we found no effect of p53 mutations in patients in the groups at high-intermediate and high risk. However, these mutations were significantly associated (P< 0.001) with low rates of complete remission (33 percent vs. 91 percent) and survival (27 percent vs. 81 percent at five years) in the groups at low and low-intermediate risk.

CONCLUSIONS

Mutations of the p53 gene are associated with a poor prognosis in patients with aggressive B-cell lymphoma.

Hypermethylation of the p15INK4B gene in myelodysplastic syndromes

Previous studies have shown that the cyclin-dependent kinase inhibitor (CDKI) genes p15INK4B and p16INK4A are frequently inactivated by genetic alterations in many malignant tumors and that they are candidate tumor-suppressor genes. Although genetic alterations in these genes may be limited to lymphoid malignancies, it has been reported that their inactivation by aberrant methylation of 5' CpG islands may be involved in various hematologic malignancies. In this study, we investigated the p15INK4B and p16INK4A genes to clarify their roles in the pathogenesis of myelodysplastic syndrome (MDS). Southern blotting analysis showed no gross genetic alterations in either of these genes. However, hypermethylation of the 5' CpG island of the p15INK4B gene occurred frequently in patients with MDS (16/32 [50%]). Interestingly, the p15INK4B gene was frequently methylated in patients with high-risk MDS (refractory anemia with excess blasts [RAEB], RAEB in transformation [RAEB-t], and overt leukemia evolved from MDS; 14/18 [78%]) compared with patients with low-risk MDS (refractory anemia [RA] and refractory anemia with ring sideroblast [RARS]; 1/12 [8%]). Furthermore, methylation status of the p15INK4B gene was progressed with the development of MDS in most patients examined. In contrast, none of the MDS patients showed apparent hypermethylation of the p16INK4A gene. These results suggest that hypermethylation of the p15INK4B gene is involved in the pathogenesis of MDS and is one of the important late events during the development of MDS.

Raf/MAPK and rapamycin-sensitive pathways mediate the anti-apoptotic function of p21Ras in IL-3-dependent hematopoietic cells

The Ras signal transduction pathway is activated by a number of hematopoietic cytokines and is implicated in the prevention of apoptotic death in hematopoietic cells. Recent studies have provided evidence that the downstream of Ras is highly divergent and several independent pathways appear to mediate distinct biological functions of Ras. In the present study, we investigated the downstream pathway(s) of Ras responsible for the maintenance of hematopoietic cell survival by using various mutants of signaling molecules. Activation of the Raf/MAPK pathway in interleukin (IL) 3-dependent cells by expression of an oncogenic Raf or a Ras mutant (G12V/T35S) prevented apoptosis following IL-3 deprivation. In contrast, another Ras mutant (G12V/V45E), which is apparently incapable of activating MAPK, efficiently blocked apoptosis as well. It is therefore likely that the activation of the Raf/MAPK pathway is not an absolute requirement for the prevention of apoptosis, and there appears to be a Raf/MAPK-independent pathway that contributes to hematopoietic cell survival. Since Ras(G12V/V45E) was able to cause the phosphorylation of p70/S6 kinase, we inhibited the S6 kinase pathway by rapamycin and by wortmannin, and found that the anti-apoptotic function of Ras(G12V/V45E), but not of Ras(G12V), was critically influenced by both inhibitors. These results indicate that the Raf/MAPK and a rapamycin/wortmannin-sensitive pathways mediate Ras function to prevent apoptotic death in hematopoietic cells.

[Relationship between knee pain and X-ray findings of osteoarthritis with reference to bone mineral density measured by computed X-ray densitometry]

We studied the relation between performance of activities of daily living and X-ray findings of osteoarthritis of the knee in aged persons. We made Covariance Structure Analysis models of knee pain, X-ray findings and bone mineral density as measured by computed X-ray densitometry. The subjects were 257 women aged from 47 to 88 years who were outpatients at an orthopedic clinic. The best-fit model indicated that loss of bone mineral density in metacarpals was associated with X-ray findings of knee-joint degeneration, as well as with knee pain. No relationship was found between knee-joint degeneration and knee pain. These results suggest that bone mineral density should be taken into consideration when interpreting X-ray findings of knee pain. This model incorporates the effects of degeneration of the subchondral bone. In summary, we should use measurements of bone mineral density along with X-ray findings for the diagnosis and treatment of knee osteoarthritis. We may be able to precisely predict knee pain caused by osteoarthritis, by analysis of a model that includes a lesion in joint cartilage.

Therapeutic results of resection, transcatheter arterial embolization and percutaneous transhepatic ethanol injection in 3225 patients with hepatocellular carcinoma: a retrospective multicenter study

The outcome in 3225 patients with hepatocellular carcinoma (HCC) was studied in groups with equivalent prognosis treated with resection, transcatheter arterial embolization (TAE), and percutaneous transhepatic ethanol injection (PEI). Significant factors for better clinical background included a tumor diameter of < or = 30 mm, tumor number < or = 3 and (clinical) Stage I. In patients with Stage I disease having tumors of < or = 30 mm and < or = 3 in number, survival afer resection and PEI did not differ, while survival after TAE was significantly worse. In those patients with Stage II disease, survival after PEI was significantly better than after resection or TAE. In patients with Stage I or II disease having tumors > or = 31 in size and < or = 3 number, survival after resection was significantly better than after TAE. In patients with Stage I disease having tumors of > or = 31 mm and > or = 4 in number, survival after resection was significantly better than after TAE. Our conclusions are as follows. Firstly, resection or PEI is recommended for patients with Stage I disease having < or = 3 tumors all < or = 30 mm in size. Secondly, PEI is recommended for patients with Stage II disease having < or = 3 tumors all < or = 30 mm in size. Thirdly, for patients with Stage I disease having tumors 31 mm or larger in size, whatever the number of tumors, resection should be selected rather than TAE.

Complementarity determining region-III is a useful molecular marker for the evaluation of minimal residual disease in mantle cell lymphoma

Bone marrow (BM) and peripheral blood (PB) involvement in 10 patients with mantle cell lymphoma (MCL) was analysed by a polymerase chain reaction (PCR)-mediated RNase protection assay. The complementarity determining regions (CDR)-III of all 10 MCLs examined was amplified efficiently with consensus V(H) and J(H) primers by PCR. and BM and/or PB involvement was evaluated by RNase protection assay in all 10 patients examined. Our assay showed BM and/or PB of the entire group to have neoplastic cells at presentation, despite the fact that eight patients were found to have BM and/or PB involvement on the basis of morphological examination and/or surface marker analysis. We also examined minimal residual disease (MRD) after conventional chemotherapy, and detected MRD in a patient in complete remission (CR). Although previous studies have shown that t(11;14) breakpoint amplification by PCR was only applicable to about 30-40% of cases, the present study indicates that CDR-III is a useful molecular marker and the PCR-mediated RNase protection assay is a good tool for the evaluation of MRD in MCL. It is suggested that BM and PB of MCL patients are quite frequently involved at presentation and even after conventional chemotherapy at the molecular level.

GPI-anchor synthesis in mammalian cells: genes, their products, and a deficiency

Protein GPI anchors are ubiquitous in eukaryotic cells. More than 50 mammalian proteins are anchored to the membrane via GPI. GPI anchoring is a posttranslational modification occurring in the endoplasmic reticulum where preassembled GPI anchor precursors are transferred to proteins bearing a C-terminal GPI signal sequence. The GPI anchor precursors are synthesized in the endoplasmic reticulum by sequential addition of sugar and other components to phosphatidylinositol. More than ten genes participate in this biosynthetic pathway, eleven of the mammalian genes having been cloned by means of complementation of mutant cells that are defective in this pathway or based on sequence homology to previously cloned yeast counterparts. A somatic mutation in one of those genes, PIG-A, involved in the first reaction step, is responsible for the hemolytic disease, paroxysmal nocturnal hemoglobinuria.

Tissue-specific knockout of the mouse Pig-a gene reveals important roles for GPI-anchored proteins in skin development

Glycosylphosphatidylinositol (GPI)-anchored proteins are widely distributed on plasma membranes of eukaryotes. More than 50 GPI-anchored proteins have been shown to be spatiotemporally expressed in mice with a deficiency of GPI-anchor biosynthesis that causes embryonic lethality. Here, we examine the functional roles of GPI-anchored proteins in mouse skin using the Cre-loxP recombination system. We disrupted the Pig-a gene, an X-linked gene essential for GPI-anchor biosynthesis, in skin. The Cre-mediated Pig-a disruption occurred in skin at almost 100% efficiency in male mice bearing two identically orientated loxP sites within the Pig-a gene. Expression of GPI-anchored proteins was completely absent in the skin of these mice. The skin of such mutants looked wrinkled and more scaly than that of wild-type mice. Furthermore, histological examination of mutant mice showed that the epidermal horny layer was tightly packed and thickened. Electron microscopy showed that the intercellular space was narrow and there were many small vesicles embedded in the intercellular space that were not observed in equivalent wild-type mouse skin preparations. Mutant mice died within a few days after birth, suggesting that Pig-a function is essential for proper skin differentiation and maintenance.