A dual-specificity phosphatase Cdc25B is an unstable protein and triggers p34(cdc2)/cyclin B activation in hamster BHK21 cells arrested with hydroxyurea.

By incubating at 30 degrees C in the presence of an energy source, p34(cdc2)/cyclin B was activated in the extract prepared from a temperature-sensitive mutant, tsBN2, which prematurely enters mitosis at 40 degrees C, the nonpermissive temperature (Nishimoto, T. , E. Eilen, and C. Basilico. 1978. Cell. 15:475-483), and wild-type cells of the hamster BHK21 cell line arrested in S phase, without protein synthesis. Such an in vitro activation of p34(cdc2)/cyclin B, however, did not occur in the extract prepared from cells pretreated with protein synthesis inhibitor cycloheximide, although this extract still retained the ability to inhibit p34(cdc2)/cyclin B activation. When tsBN2 cells arrested in S phase were incubated at 40 degrees C in the presence of cycloheximide, Cdc25B, but not Cdc25A and C, among a family of dual-specificity phosphatases, Cdc25, was lost coincidentally with the lack of the activation of p34(cdc2)/cyclin B. Consistently, the immunodepletion of Cdc25B from the extract inhibited the activation of p34(cdc2)/cyclin B. Cdc25B was found to be unstable (half-life < 30 min). Cdc25B, but not Cdc25C, immunoprecipitated from the extract directly activated the p34(cdc2)/cyclin B of cycloheximide-treated cells as well as that of nontreated cells, although Cdc25C immunoprecipitated from the extract of mitotic cells activated the p34(cdc2)/cyclin B within the extract of cycloheximide-treated cells. Our data suggest that Cdc25B made an initial activation of p34(cdc2)/cyclin B, which initiates mitosis through the activation of Cdc25C.

Detachment of cultured cells from the substratum induced by the neutrophil-derived oxidant NH2Cl: synergistic role of phosphotyrosine and intracellular Ca2+ concentration.

The neutrophil-derived, membrane-permeating oxidant, NH2Cl, (but not the non-membrane-permeating chloramine, taurine-NHCl) induced detachment of fetal mouse cardiac myocytes and other cell types (fibroblasts, epithelial cells, and endothelial cells) from the culture dish, concomitant with cell shrinkage ("peeling off"). Stimulated human neutrophils also induced peeling off of cultured mouse cardiac myocytes when the latter were pretreated with inhibitors of .OH and elastase. Immunofluorescence microscopy revealed that the NH2Cl-induced peeling off of WI-38 fibroblasts is accompanied by disorganization of integrin alpha 5 beta 1, vinculin, stress fibers, and phosphotyrosine (p-Tyr)-containing proteins. Decrease in the content of the p-Tyr-containing proteins of the NH2Cl-treated cells was analyzed by immunoblotting techniques. Coating of fibronectin on the culture dish prevented both NH2Cl-induced peeling off and a decrease in p-Tyr content. Preincubation with a protein-tyrosine phosphatase inhibitor, sodium orthovanadate (Na3VO4), also prevented NH2Cl-induced peeling off, suggesting that dephosphorylation of p-Tyr is necessary for peeling off. NH2Cl-induced peeling off was accompanied by an increase in intracellular Ca2+ concentration ([Ca2+]i) in mouse cardiac myocytes and WI-38 fibroblasts. The absence of extracellular Ca2+ prevented both NH2Cl-induced peeling off and increased [Ca2+]i, both of which did occur on subsequent incubation of the cells in Ca2+-containing medium. These observations suggest that an increase in [Ca2+]i is also necessary for peeling off. Depletion of microsomal and cytosolic Ca2+ by incubation with the microsomal Ca2+-ATPase inhibitor 2',5'-di(tert-butyl)-1,4-benzohydroquinone (BHQ) plus EGTA prevented both NH2Cl-induced increases in [Ca2+]i and peeling off. Direct inhibition of microsomal Ca2+ pump activity by NH2Cl may participate in the NH2Cl-induced [Ca2+]i increment. A combination of p-Tyr dephosphorylation by genistein (an inhibitor of tyrosine kinase) and an increase in [Ca2+]i by BHQ could also induce peeling off. All these observations suggest a synergism between p-Tyr dephosphorylation and increased [Ca2+]i in NH2Cl-induced peeling off.

When overexpressed, a novel centrosomal protein, RanBPM, causes ectopic microtubule nucleation similar to gamma-tubulin.

A novel human protein with a molecular mass of 55 kD, designated RanBPM, was isolated with the two-hybrid method using Ran as a bait. Mouse and hamster RanBPM possessed a polypeptide identical to the human one. Furthermore, Saccharomyces cerevisiae was found to have a gene, YGL227w, the COOH-terminal half of which is 30% identical to RanBPM. Anti-RanBPM antibodies revealed that RanBPM was localized within the centrosome throughout the cell cycle. Overexpression of RanBPM produced multiple spots which were colocalized with gamma-tubulin and acted as ectopic microtubule nucleation sites, resulting in a reorganization of microtubule network. RanBPM cosedimented with the centrosomal fractions by sucrose- density gradient centrifugation. The formation of microtubule asters was inhibited not only by anti- RanBPM antibodies, but also by nonhydrolyzable GTP-Ran. Indeed, RanBPM specifically interacted with GTP-Ran in two-hybrid assay. The central part of asters stained by anti-RanBPM antibodies or by the mAb to gamma-tubulin was faded by the addition of GTPgammaS-Ran, but not by the addition of anti-RanBPM anti- bodies. These results provide evidence that the Ran-binding protein, RanBPM, is involved in microtubule nucleation, thereby suggesting that Ran regulates the centrosome through RanBPM.

Self-organization of microtubule asters induced in Xenopus egg extracts by GTP-bound Ran.

The nucleotide exchange activity of RCC1, the only known nucleotide exchange factor for Ran, a Ras-like small guanosine triphosphatase, was required for microtubule aster formation with or without demembranated sperm in Xenopus egg extracts arrested in meiosis II. Consistently, in the RCC1-depleted egg extracts, Ran guanosine triphosphate (RanGTP), but not Ran guanosine diphosphate (RanGDP), induced self-organization of microtubule asters, and the process required the activity of dynein. Thus, Ran was shown to regulate formation of the microtubule network.

Diffusion-weighted magnetic resonance imaging of endometrial cancer: differentiation from benign endometrial lesions and preoperative assessment of myometrial invasion.

BACKGROUND: Uterine endometrial cancer is the most common gynecologic malignancy, and benign endometrial hyperplasia or polyps should be differentiated from endometrial cancer. In evaluating endometrial cancer on magnetic resonance imaging (MRI), the assessment of the depth of myometrial invasion is important because it closely correlates with the patient's prognosis. PURPOSE: To verify the feasibility of diffusion-weighted magnetic resonance imaging (DWI) to distinguish benign and malignant endometrial lesions, and to evaluate myometrial invasion of endometrial cancer. MATERIAL AND METHODS: Sixty-seven endometrial lesions including 45 cancers and 22 benign lesions (hyperplasia and polyps) were evaluated by DWI with apparent diffusion coefficient (ADC) measurement. The staging accuracies of DWI and gadolinium-enhanced T1-weighted images in the assessment of myometrial invasion were evaluated in 33 patients with endometrial cancer. RESULTS: The ADC values (x10(-3) mm(2)/s) in cancer and benign lesions were 0.84+/-0.19 and 1.58+/-0.36, respectively (P<0.01). The staging accuracy (superficial or deep myometrial invasion) was 94% for DWI and 88% for gadolinium-enhanced T1-weighted images. Coexisting adenomyosis and infiltrative myometrial invasion caused staging errors on gadolinium-enhanced T1-weighted images, whereas DWI could demonstrate the tumor extent correctly. CONCLUSION: DWI provides helpful information in evaluating benign and malignant endometrial lesions.

Diffusion-weighted magnetic resonance imaging of urinary epithelial cancer with upper urinary tract obstruction: preliminary results.

BACKGROUND: Various malignant tumors of the body show high signal intensity on diffusion-weighted magnetic resonance imaging (DWI). In the genitourinary region, DWI is expected to have a role in detecting urinary epithelial cancer noninvasively. PURPOSE: To demonstrate the feasibility of DWI for the diagnosis of urinary epithelial cancer with upper urinary tract obstruction. MATERIAL AND METHODS: Twenty upper urinary tract cancers in 16 patients were evaluated by high-b-value DWI (b=800 s/mm(2)). The signal intensity was visually evaluated, and the apparent diffusion coefficients (ADCs) were measured. RESULTS: All urinary epithelial cancers showed high signal intensity on DWI. The ADC in cancerous lesions was 1.31+/-0.27 x 10(-3) mm(2)/s, which was significantly lower than that of the lumens of the ureter or renal pelvis (3.32+/-0.44 x 10(-3) mm(2)/s; P<0.001). Maximum intensity projection images of DWI in combination with static-fluid MR urography provided three-dimensional entire urinary tract imaging with the extension of tumors. CONCLUSION: DWI is useful in the tumor detection and in evaluating the tumor extension of urinary epithelial cancer in patients with upper urinary tract obstruction.

High-b-value diffusion-weighted magnetic resonance imaging of pancreatic cancer and mass-forming chronic pancreatitis: preliminary results.

BACKGROUND: Mass-forming chronic pancreatitis may mimic a pancreatic cancer on dynamic computed tomography (CT) and magnetic resonance (MR) imaging, and preoperative differential diagnosis is often difficult. Recently, the usefulness of diffusion-weighted MR imaging (DWI) in the diagnosis of pancreatic cancer has been reported in several studies. PURPOSE: To determine whether high-b-value DWI can distinguish pancreatic cancer from benign mass-forming chronic pancreatitis. MATERIAL AND METHODS: Twenty pancreatic cancers and four cases of mass-forming chronic pancreatitis were evaluated by high-b-value DWI (b=800 s/mm(2)). The signal intensity on DWI was visually evaluated, and the isotropic apparent diffusion coefficients (ADCs) were measured. RESULTS: All twenty pancreatic cancers showed high signal intensity (18 showed very high, two showed slightly high) on DWI. None of the mass-forming chronic pancreatitis cases showed very high intensity (three showed iso to low, one showed slightly high) on DWI. The ADCs in the pancreatic cancer and mass-forming chronic pancreatitis were 1.38 +/- 0.32 x 10(-3) mm(2)/s and 1.00 +/- 0.18 x 10(-3) mm(2)/s, respectively (P < 0.05). CONCLUSION: On high-b-value DWI, most pancreatic cancers showed very high signal intensity, and may hence be distinguished from benign mass-forming chronic pancreatitis based on our preliminary results.

Licensing regulators Geminin and Cdt1 identify progenitor cells of the mouse CNS in a specific phase of the cell cycle.

Nervous system formation integrates control of cellular proliferation and differentiation and is mediated by multipotent neural progenitor cells that become progressively restricted in their developmental potential before they give rise to differentiated neurons and glial cells. Evidence from different experimental systems suggests that Geminin is a candidate molecule linking proliferation and differentiation during nervous system development. We show here that Geminin and its binding partner Cdt1 are expressed abundantly by neural progenitor cells during early mouse neurogenesis. Their expression levels decline at late developmental stages and become undetectable upon differentiation. Geminin and Cdt1 expressing cells also express Sox2 while no overlap is detected with cells expressing markers of a differentiated neuronal phenotype. A fraction of radial glial cells expressing RC2 and Pax6 are also immunoreactive for Geminin and Cdt1. The majority of the Geminin and Cdt1 expressing cell populations appears to be distinct from fate-restricted precursor cells expressing Mash1 or Neurogenin2. Bromo-deoxy-uridine (BrdU) incorporation experiments reveal a cell cycle specific expression in neural progenitor cells, with Geminin being present from S to M phase, while Cdt1 expression characterizes progenitor cells in G1 phase. Furthermore, in vitro differentiation of adult neurosphere cultures shows downregulation of Geminin/Cdt1 in the differentiated state, in line with our data showing that Geminin is present in neural progenitor cells of the CNS during mouse embryogenesis and adulthood and becomes downregulated upon cell fate specification and differentiation. This suggests a role for Geminin in the formation and maintenance of the neural progenitor cells.

RCC1, a regulator of mitosis, is essential for DNA replication.

Temperature-sensitive mutants in the RCC1 gene of BHK cells fail to maintain a correct temporal order of the cell cycle and will prematurely condense their chromosomes and enter mitosis at the restrictive temperature without having completed S phase. We have used Xenopus egg extracts to investigate the role that RCC1 plays in interphase nuclear functions and how this role might contribute to the known phenotype of temperature-sensitive RCC1 mutants. By immunodepleting RCC1 protein from egg extracts, we find that it is required for neither chromatin decondensation nor nuclear formation but that it is absolutely required for the replication of added sperm chromatin DNA. Our results further suggest that RCC1 does not participate enzymatically in replication but may be part of a structural complex which is required for the formation or maintenance of the replication machinery. By disrupting the replication complex, the loss of RCC1 might lead directly to disruption of the regulatory system which prevents the initiation of mitosis before the completion of DNA replication.

Premature chromosome condensation is induced by a point mutation in the hamster RCC1 gene.

At the nonpermissive temperature, premature chromosome condensation (PCC) occurs in tsBN2 cells derived from the BHK cell line, which can be converted to the Ts+ phenotype by the human RCC1 gene. To prove that the RCC1 gene is the mutant gene in tsBN2 cells, which have RCC1 mRNA and protein of the same sizes as those of BHK cells, RCC1 cDNAs were isolated from BHK and tsBN2 cells and sequenced to search for mutations. The hamster (BHK) RCC1 cDNA encodes a protein of 421 amino acids homologous to the human RCC1 protein. In a comparison of the base sequences of BHK and BN2 RCC1 cDNAs, a single base change, cytosine to thymine (serine to phenylalanine), was found in the 256th codon of BN2 RCC1 cDNA. The same transition was verified in the RCC1 genomic DNA by the polymerase chain reaction method. BHK RCC1 cDNA, but not tsBN2 RCC1 cDNA, complemented the tsBN2 mutation, although both have the same amino acid sequence except for one amino acid at the 256th codon. This amino acid change, serine to phenylalanine, was estimated to cause a profound structural change in the RCC1 protein.

Chromosome condensation caused by loss of RCC1 function requires the cdc25C protein that is located in the cytoplasm.

We cloned the hamster cdc25C cDNA by using the human cdc25C cDNA as a probe and prepared an antibody to Escherichia coli-produced hamster cdc25C protein that is specific to the human cdc25C protein. The microinjected antibody inhibited a chromosome condensation induced by tsBN2 mutation, indicating that the cdc25C protein is required for an activation of p34cdc2 kinase caused by loss of RCC1 function. The hamster cdc25C protein located in the cytoplasm, prominently in a periphery of the nuclei of cells arrested with hydroxyurea, and seemed to move into the nuclei by loss of RCC1 function. Also, we found a molecular shift of the cdc25C protein in cells showing premature chromosome condensation (PCC), in addition to normal mitotic cells. This molecular-shift appeared depending on an activation of p34cdc2 kinase.

[Quality control (QC) of CT on rail system (FOCAL Unit) with a micro-multi leaf collimator (mMLC) using new GafChromic film for stereotactic radiotherapy].

PURPOSE: Recent years, CT on rail system was reported to be useful as a tool for image-guided radiotherapy (IGRT). This system was clinically developed with the aim of stereotactic irradiation (STI) for brain, lung, liver, prostate and other sites. Quality assurance and quality control (QC) is an important issue in CT on rail system to assure geometric accuracies. The purpose of this study is to estimate the geometric accuracies of our CT on rail system using a detachable micro-multi leaf collimator (mMLC) with new type radiochromic films. Carrying out our original QC program, translational errors, setup reproducibility, beam misalignment and beam characteristics were evaluated. METHODS AND MATERIALS: We have studied with CT on rail system (FOCAL unit, Toshiba Medical systems, Tokyo, Japan) and mMLC unit (Accuknife, Direx Inc., Tokyo, Japan). We have developed original alignment phantom and small steel markers (2 mm phi) were implanted on its surface at certain intervals. Firstly, we have evaluated the accuracy of self-moving CT gantry and CT resolutions for cranio-caudal directions by changing slice thickness. And then using the phantom, we have measured the accuracy and reproducibility of geometric isocenter of the linac side and the CT gantry side by scanning the phantom. We have also measured the geometric changes of the common treatment couch by weight-loaded test (up to 135 kgw). To estimate dosimetric and geometric accuracies with the mMLC unit, the misalignment of the beam axes (gantry, collimator and couch rotation axis), mMLC leaf positions, and dose distributions for the verification plan were measured with new type GafChromic films (GafChromic-RTQA, ISP Inc., USA) and cylindrical phantom. The dose characteristics of the GafChromic film were also evaluated. RESULTS: The reproducibility of the self-moving CT gantry have a good agreement within 1 mm. Weight-load test have shown a good reliability within 2 mm at the common treatment couch. The translational precision of the common treatment couch was 0.0 +/- 0.1 mm at linac side and -0.2 +/- 0.5 mm at CT gantry side. The misalignments of beam axes have been kept within 0.4 mm at maximum. Gap test have shown the accuracies of the mMLC leaf positions, which is needed to keep within 1 mm by a routine calibration. CONCLUSIONS: To practice quality control program for the FOCAL unit and the mMLC unit is essential for a regular interval to reduce systematic errors. New type radiochromic film would be useful for a verification tool as alternative to conventional film.

Expression of the licensing factors, Cdt1 and Geminin, in human colon cancer.

Licensing of chromatin for replication is an evolu-tionarily conserved step in the control of cell division and genomic integrity. Proteins that participate in licensing have been recently documented to denote the proliferative state of cells and they have been proposed as diagnostic and prognostic markers in human cancer. Cdt1 was recently discovered as an important licensing factor, that is inhibited by Geminin. In the present study we analyzed Cdt1 and Geminin expression in human colon cancer. We showed that Cdt1 protein is highly expressed in human neoplastic lesions of the colon while its cell-cycle phase-specific expression profile appears preserved during human carcinogenesis. Similarly, Geminin, Cdt1's inhibitor, is also overexpressed in colon carcinomas and its expression correlates with significant clinicopathological parameters of the disease. Moreover, both Cdt1 and Geminin expression are severely downregulated upon differentiation of Caco-2 cells, an in vitro model of intestinal epithelial differentiation.

Evidence for the presence of differently glycosylated forms of prorenin in the plasma of anephric man.

Previously, we unexpectedly observed that plasma inactive renin (trypsin-activatable renin) in bilaterally nephrectomized rats is not prorenin. To determine whether plasma inactive renin in anephric man is prorenin, we examined the immunological and biochemical properties of plasma inactive renin from five anephric patients. There were significant concentrations of inactive renin (5.33 +/- 2.08 ng/L.s) in plasma of anephric patients, while active renin was negligible (0.06 +/- 0.01 ng/L.s). The inactive renin from anephric patients could be immunoprecipitated 97 +/- 1% by specific antiserum against the prosegment portion of prorenin. Specific antimature renin serum completely inhibited the angiotensin-I-generating activity of inactive renin induced by trypsin treatment. The molecular mass of inactive renin from anephric patients (49.0 +/- 0 kDa), estimated by gel permeation high performance liquid chromatography, was similar to that of normal human plasma prorenin (48.2 +/- 0.8 kDa). These results indicate that plasma inactive renin in anephric man is prorenin, findings different from our previous observations obtained in anephric rats. Concanavalin-A chromatography separated inactive renin from anephric patients into three forms, including the column-unbound form, the loosely bound form, and the tightly bound form. Thus, in anephric man, differently glycosylated multiple forms of prorenin are released into the circulation from an extrarenal organ(s).

Immunoreactive beta-endorphin in human cerebrospinal fluid.

To elucidate the nature of beta-endorphin-like immunoreactivity in human cerebrospinal fluid (CSF) and its relationship with plasma beta-endorphin, plasma and CSF specimens were obtained simultaneously. Gel chromatography revealed that beta-endorphin-like immunoreactivity in CSF consisted of two components with elution positions compatible to those of beta-endorphin and beta-lipotropin (beta-LPH), respectively, and an additional larger molecule. The beta-endorphin level in CSF obtained from four nonendocrine patients was 17.9 +/- 2.3 pg/ml (mean +/- SE) and corresponded to 20% of beta-endorphin-like immunoreactivity. The predominant componet in CSF was either beta-LPH or the larger molecule. beta-Endorphin levels in CSF were consistently higher than those in plasma, and there seemed to be no relationship between them. One patient with Nelson's syndrome had a CSF beta-endorphin level of 14.8 pg/ml, although the plasma level was 784 pg/ml. On the other hand, one patient under glucocorticoid treatment had a CSF beta-endorphin level of 13.0 pg/ml and an undetectably low plasma level. It is concluded that 1) beta-endorphin-like immunoreactivity consists of beta-endorphin, beta-LPH, and possibly the precursor molecule; and 2) there exists marked dissociation between plasma and CSF beta-endorphin levels, suggesting the possible central nervous system origin of beta-endorphin in CSF.

A novel nuclear protein, Twa1, and Muskelin comprise a complex with RanBPM.

A truncated human RanBPM has been isolated as a protein binding to Ran, Ras-like nuclear small GTPase. Full-sized human RanBPM cDNA which was recently isolated, was found to encode a protein of 90 kDa which comprises a large protein complex. Consistent with this finding, several proteins were found to be co-precipitated with RanBPM by immunoprecipitation analysis. Accordingly, in the present study, we screened the human cDNA library by the two-hybrid method using RanBPM cDNA as bait. One novel protein designated as Twa1 (Two hybrid associated protein No. 1 with RanBPM), and two known proteins, a human homologue (hMuskelin) of mouse Muskelin and HSMpp8 were isolated repeatedly. Twa1 was well conserved through evolution and was localized within the nucleus. Interestingly, in addition to Muskelin and RanBPM, Twa1 was found to possess the LisH-CTLH motif which is detected in proteins involved in microtubule dynamics, cell migration, nucleokinesis and chromosome segregation. These functions overlap with functions suggested for the RanGTPase cycle. Immunoprecipitation and gel-filtration analyses indicated that both Twa1 and hMuskelin did indeed comprise a protein complex with RanBPM. Taken together with the fact that RanBPM interacts with Ran, our present findings suggested that there is an as yet uncovered function of the RanGTPase cycle.

Full-sized RanBPM cDNA encodes a protein possessing a long stretch of proline and glutamine within the N-terminal region, comprising a large protein complex.

Previously isolated RanBPM, a Ran-binding protein in the microtubule-organizing center, which had been thought to play a role in Ran-stimulated microtubule assembly, turned out to be a truncated protein. To clarify the function of RanBPM, we cloned the full-sized RanBPM cDNA that encodes a 90 kDa protein, compared to the previously isolated cDNA that encoded a 55 kDa protein. The newly cloned 5' coding region contains a great number of cytidine and guanidine nucleotides, like the CpG island. Thus, full-sized RanBPM cDNA encodes a long stretch of proline and glutamine residues in the N-terminal region. It comprises a protein complex of more than 670 kDa. Ran was detected in this complex when RanBPM and Ran were both ectopically expressed. New antibodies to RanBPM were prepared against three different regions of RanBPM. All of them detected a 90 kDa protein that is predominantly localized both in the nucleus and in the cytoplasmic region surrounding the centrosome, but none of them stained the centrosome. In this context, our previous notion that RanBPM is a centrosomal protein should be discarded. RanBPM is well conserved in the animal kingdom. It may play an important role in uncovering Ran-dependent nuclear events.

Primary structure of alpha-bungarotoxin. Six amino acid residues differ from the previously reported sequence.

alpha-Bungarotoxin (alpha-BuTx) was isolated from the venom of the Formosan banded krait (Bungarus multicinctus). The amino acid sequence was determined by a combination of conventional methods. In contrast to the sequence of alpha-BuTx reported by Mebs et al. ([1971) Biochem. Biophys. Res. Commun. 44, 711-716], our results revealed the presence of Ser-Pro-Ile, Pro-His and Gln-Arg at positions 9-11, 67-68 and 71-72 from the amino-terminal, respectively, and not Ile-Pro-Ser, His-Pro and Arg-Gln as reported previously.

The risk of development of HTLV-I-associated myelopathy/tropical spastic paraparesis among persons infected with HTLV-I.

Using data obtained in national surveys of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) conducted in Japan in 1987 and 1988, we estimated the yearly and lifetime risk that HAM/TSP will develop in an HTLV-I-infected person. "Definite" HAM/TSP was defined as slowly progressive myelopathy with antibodies to HTLV-I in both serum and cerebrospinal fluid. Estimates of HTLV-I infection rates in eight endemic prefectures, by age group and sex, were obtained from serologic studies of blood donors; population figures, by age group, sex, and prefecture, were obtained from the census. Of 589 definite cases of HAM/TSP reported nationally, 397 occurred in residents of the eight endemic prefectures; of these, 170 reported onset of illness during the years 1982-1988 (average incidence, 24.3 cases/year). Using the estimated HTLV-I infection rates and the 1985 census figures, we estimated the number of HTLV-I-infected persons in the eight prefectures in 1985 at 794,800. We therefore estimated the incidence of HAM/TSP among HTLV-I-infected persons at 3.1 x 10(-5) cases/year; assuming a lifetime of 75 years, the lifetime incidence is approximately one quarter of 1%. This estimate is important in counseling persons such as blood donors found to be infected with HTLV-I.

Immunologic studies of a case of myasthenia gravis associated with pemphigus vulgaris after thymomectomy.

A case of myasthenia gravis was associated with thymoma and pemphigus vulgaris. The bullous lesions developed after partial thymomectomy, cobalt (60Co) irradiation, and 3 days' extensive sunbathing, although a retrospective study of the patient's sera by quantitative indirect immunofluorescence method indicated that antiepithelial antibody already was positive before the clinical appearance of pemphigus vulgaris. Serial observation of the patient's clinical course and titrations of antiepithelial, antimuscle, and antithymus antibodies suggested a reverse relationship between the severity of myasthenia gravis and titers of antimuscle and anitithymus antibodies, and a parallel relationship between pemphigus vulgaris and antiepithelial antibody. Review of the literature suggests a close relationship between pemphigus vulgaris and myasthenia gravis and thymoma, particularly thymoma injured by medical procedures.