The F wave disappears due to impaired excitability of motor neurons or proximal axons in inflammatory demyelinating neuropathies

OBJECTIVES

Investigation of pathophysiology of F wave disappearance in demyelinating neuropathies.

METHODS

The peripheral motor nerve conduction was studied by motor evoked potential (MEP) on transcranial magnetic stimulation as well as conventional nerve conduction studies before and after the treatment in 26 patients with inflammatory demyelinating neuropathies. In addition, serum antiganglioside antibodies in the acute or active stage were examined.

RESULTS

The F wave was abolished in 10 patients. Seven of the 10 patients showed motor evoked potentials (MEPs) on transcranial magnetic stimulation that ranged from 1-4 mV. In six of them the F wave reappeared in the recovery stage, but the MEP size did not change. This may be caused by humoral factors, because the F wave reappeared immediately after plasma exchange or intravenous immunoglobulin treatment. A correlation of F wave disappearance with the presence of serum antiganglioside antibodies was found.

CONCLUSIONS

The major pathophysiology of F wave disappearance in demyelinating neuropathies is impairment of motor neuron excitability or prolonged refractoriness of the most proximal axon for backfiring. The conventional interpretation that absent F waves suggest a conduction block at the proximal site is often inadequate.

Prostate cancer--biology of metastasis and its clinical implications

Prostate cancer is one of the most commonly diagnosed cancers and is a major cause of cancer death in men. Although the majority of the diagnosed prostate cancers will remain localized and never produce clinical symptoms during the lifetime of the host, a subset of these cancers will progress to a more malignant state requiring therapeutic intervention. Acquisition of metastatic ability by prostatic cancer cells is the most lethal aspect of prostatic cancer progression. Once this has occurred, definitive therapy is required before the initially localized metastatic cells escape from the prostate. At present, metastatic prostate cancer is incurable. Therefore, there is an urgent need to develop molecular markers that can be used to predict the metastatic potential of prostate cancers. Using somatic cell hybridization, we have demonstrated that acquisition of metastatic ability requires both the loss of metastasis-suppressor function(s) and the activation of oncogenes. In further studies using micro-cell-mediated chromosomal transfer, we located genes on human chromosome, 8, 10cen-q23, 11p11.2-13, and 17pter-q23, which, when introduced into rat prostatic cancer cells, are capable of suppressing their metastatic ability without affecting their tumorigenicity or growth rate in vivo. Initially we focused upon the human chromosome 11p11.2-13 region to clone metastasis-suppressor gene(s) positionally. One such gene, termed KAI-1, encodes a membrane glycoprotein. KAI-1 has been mapped to the p11.2 region of human chromosome 11 by fluorescence in-situ hybridization analysis. Expression of KAI-1 has been detected in all normal human tissues thus far tested, including prostate tissue. When introduced into rat metastatic prostatic cancer cells, KAI-1 significantly suppressed the metastasis without affecting the tumor growth rate. KAI-1 expression is high in human normal prostate and benign prostatic hyperplasia but is dramatically lower in cancer cell lines derived from metastatic prostate tumors.

Studies on an experimental system for the invasion of Theileria sergenti merozoite into erythrocytes

The entry of Theileria sergenti merozoite into erythrocytes was examined to establish an in vitro experimental system for merozoite invasion. Free merozoites (1 x 10(8)) were incubated with erythrocytes (2 x 10(7)) in RPMI-1640 containing various concentrations of fetal bovine serum (FBS). The invasion assay was examined at various temperatures and pH concentrations. The results showed that merozoite invasion was accelerated by the addition of FBS and by incubation at 37 degrees C at pH 6.5-7.5. To investigate how enzymatic activity contributes to the entry of T. sergenti merozoites, the inhibitory effect on the merozoite invasion was examined by using protease inhibitors. An inhibitory effect on the invasion of merozoites was observed in the medium containing 1,10-phenanthroline and ethylenediaminetetraacetic acid disodium salt which are classified as metalloprotease inhibitors. The results suggest that FBS plays an important role in the effective invasion of merozoite into erythrocytes and that enzymatic activity may affect the invasion of merozoite into the host cell.

Intracranial metastases of hepatocellular carcinoma: CT and MRI

We report clinical characteristics and CT and MRI in 16 patients with brain metastases due to hepatocellular carcinoma (HCC). Eight of these 16 patients presented with apoplexy-like symptoms (50%). Pulmonary metastases were found in 13 cases (81.3%). The mean survival from the appearance of cerebral metastases to death was 6.2 weeks, which is one of the shortest survival terms in metastatic brain tumours. Haemorrhagic brain metastases were observed in 14 patients (87.5%) with a tendency for the frequency of bleeding to increase in proportion to the size of the tumour. On both contrast-enhanced CT and MRI, metastatic brain tumours enhanced strongly, suggesting that brain metastases, like HCC, are also hypervascular. MRI is useful in evaluating brain metastases from HCC, especially in order to differentiate tumour from haemorrhage. Our results demonstrated a poor prognosis and bleeding tendency of brain metastases due to HCC and showed the usefulness of CT and MRI in achieving a correct diagnosis.

[Mass screening for prostate cancer in Japan]

Since 1975 mass screening for prostate cancer has been performed in Japan. The Prostate Research Foundation has analysed the data every year that collected from all institutes performing a mass screening. Up to 1993, 67, 225 subjects were examined. The detection rate of prostate cancer was 0.69%. Approximately half of the cancer were stage B, and the subjects who have metastatic stage were only 20% and the pattern of stage seemed to be different from that of patients who visited hospitals. In Chiba prefecture the subjects lived in a district of south Boso peninsula received a mass screening for prostate cancer with total of 1,964 men from 1985, and 17 cancers were diagnosed (0.87%). The distribution of prostate-specific antigen (PSA) assayed with Tandem-R kit was examined using the stocked sera (n = 976) of the screening for prostate cancer in Chiba prefecture. The percentage of 0.05-4.0 ng/ml, 4.1-9.9 ng/ml, over than 10.0 ng/ml of the PSA, were 89.6%, 7.0%, 3.4%, respectively. This distribution is approximately as same as the previous reports by the United States and Canada.

Analysis of p53 gene mutations in human glioma cell lines

Seven human glioma cell lines were examined for mutations of the p53 gene and their mRNA and protein expressions. Five cell lines revealed a missense mutation at, codons 237, 245, or 273. Their p53 mRNA expression was variably distinct and not always comparable to p53 protein expression, suggesting difference in the transcriptional and posttranscriptional regulation. One cell line had a splicing mutation in intron 9 and abnormal splicing was actually demonstrated by RT-PCR analysis. The remaining 1 cell line showed no PCR-amplification of the p53 gene sequence. In an examination of the original tumor tissues, the same mutations were demonstrated in the 5 tumors examined, strongly suggesting that the mutations in the glioma cell lines were derived from their original tumor tissues.

Stimulation of mucin biosynthesis in rat gastric mucosa by FRG-8813 and its structural analogs

Certain chemical properties, which may determine the stimulatory actions of the new histamine H2 receptor antagonist, FRG-8813 (2-(furfurylsulfinyl)-N-(4-[4-(piperidinomethyl)-2-pyridyl]o xy-(Z)- 2-butenyl)acetamide), on mucin biosynthesis, were identified by considering the derivation of this drug using an organ culture system of the rat stomach. [3H]Glucosamine and [35S]sulfate incorporation was stimulated in the corpus region by FRG-8813 and its structural analog, compound A (N-[4-[[4- (piperidinylmethyl)pyridyl]-2-oxy]-(Z)-2-butenyl]phthalimide). The chronotropic response to histamine in the guinea pig right atria was suppressed by FRG-8813 in a concentration-dependent fashion. In contrast, compound A did not suppress the histamine-induced response. Ranitidine at 10(-4) M did not suppress the FRG-8813-induced increase in [3H]glucosamine incorporation into mucin. These results suggest that the pyridine derivative and amide structure are chemically important in FRG-8813 as a stimulant on mucus metabolism. Also, this effect is not directly due to histamine H2 receptor antagonism.

Ganglioneuroma: computed tomography and magnetic resonance features

12 patients who had histological proven ganglioneuromas were investigated by computed tomography (CT) and magnetic resonance (MR) imaging. CT scans (n = 11), conventional spin-echo MR images (n = 10) and dynamic MR images (n = 5) were acquired. All lesions showed a well defined, oval shape. Five lesions (42%) showed calcification which was punctate in four and coarse in one on CT. CT attenuation was predominantly low in three of 10 (30%) and intermediate in the remaining seven (70%). In all lesions MR signals were mainly of low intensity on T1 weighted images (T1WI) and of high intensity on T2 weighted images (T2WI). Dynamic MR studies in five cases showed a lack of early enhancement but gradual increasing enhancement. One case had a ganglioneuroblastoma component which showed soft-tissue density and coarse calcifications on CT scans, MR images with intermediate intensity on T1WI and T2WI and early enhancement and little washout on dynamic MR images. In conclusion, ganglioneuroma typically shows punctate calcification and low attenuation on CT and marked hyperintensity on T2WI with gradual increasing enhancement on dynamic MR images. If a ganglioneuroma has atypical CT and MR features, coexistence of a malignant component should be considered.

Exposure of postnatal rats to glucocorticoids suppresses the development of choline acetyltransferase-immunoreactive neurons: role of adrenal steroids in the development of forebrain cholinergic neurons

Rat forebrain cholinergic neurons undergo dynamic developmental changes, showing a continuous increase in choline acetyl-transferase (ChAT) activity, during the early postnatal period. In adult rats, increases in circulating glucocorticoids result in decreases in activity of forebrain neuronal ChAT, thus raising the possibility that postnatal development of forebrain cholinergic neurons results from low levels of these hormones. In the rat, the first 2 weeks postnatally are characterized by very low levels of adrenal steroids. To understand the role of endogenous glucocorticoids in the development of forebrain cholinergic neurons, we studied the changes in ChAT immunoreactivity in forebrain cholinergic neurons of postnatal rats which had received daily subcutaneous injection of the synthetic glucocorticoid dexamethasone for 8 days. Immunohistochemical analysis of the rat pup forebrain revealed nearly complete obliteration of ChAT-immunoreactive neurons in the caudate-putamen, especially in the dorsolateral region of the rostral part. At the same stage, treatment with dexamethasone induced significant decreases in both number and length of dendritic branches of ChAT-immunoreactive neurons in the substantia innominata and the diagonal band. Despite the marked alterations in the caudate-putamen and diagonal band, the ChAT-immunoreactive neurons in other forebrain structures such as globus pallidus and medial septal nucleus showed little change. In the caudate-putamen, Nissl staining and specific labeling for nuclear DNA fragmentation exhibited no increase in number of dying cells following dexamethasone treatment, therefore indicating that the loss of ChAT immunoreactivity is not due to glucocorticoid-induced cholinergic cell death. These observations demonstrated that the development of cholinergic neurons in rat pups was inhibited by prolonged glucocorticoid exposure, suggesting that low levels of adrenal steroids may promote the postnatal development of these neurons.

Squamous cell carcinoma arising in a verrucous epidermal nevus

A 74-year-old Japanese male patient with squamous cell carcinoma arising in an epidermal nevus is described. The patient had widespread warty lesions involving large parts of the body since infancy. Recently, a nodular lesion appeared on the middle part of his back and increased in size. Histologically, the nodule was diagnosed as squamous cell carcinoma and the warty lesion showed the features of epidermal nevus. The nodular lesion was totally excised and the skin defect was covered with split-thickness skin grafting. To the best of our knowledge, this is the 16th patient with malignant change of a verrucous epidermal nevus.

MR findings indicative of hemosiderin in giant-cell tumor of bone: frequency, cause, and diagnostic significance

OBJECTIVE

We studied the frequency, cause, and diagnostic significance of MR findings indicative of large amounts of hemosiderin in giant-cell tumor of bone.

MATERIALS AND METHODS

The clinical, MR, and histologic findings in 16 patients with giant-cell tumors of bone were reviewed. Eight tumors occurred in uncommon locations or in patients who were not in the usual age range; the other eight were more typical. Areas of decreased MR signal intensity considered to be caused by hemosiderin were identified. The number and distribution of RBCs within the tumor were studied histologically, and the presence of hemosiderin was determined on histologic sections made with iron stains.

RESULTS

In 10 cases in which MR images showed areas of low signal intensity, large amounts of hemosiderin were noted histologically. The low-signal-intensity areas were nodular, zonal, whorled, or diffuse and occupied at least one fifth of the tumor volume. On histologic examination, many erythrocytes were in direct contact with the tumor cells, and the hemosiderin was seen in both mononuclear and multinuclear tumor cells.

CONCLUSION

Hemosiderin is commonly seen on MR images of giant-cell tumors of bone (63%) and is probably related to the extravasated erythrocytes in the tumor and the phagocytic function of the tumor cells. This MR finding supports the diagnosis, even in giant-cell tumors in uncommon locations or in patients who are not in the typical age range.

Hepatocellular carcinoma: detection with double-phase helical CT during arterial portography

Retrospective analysis of findings at double-phase helical computed tomography (CT) during arterial portography was performed in 42 hepatocellular carcinomas (HCCs) in 31 patients. Phase 1 scanning started 30-35 seconds after the beginning of injection of contrast material; phase 2 scanning started 10-18 seconds after the end of phase 1. The overall detection rate for HCCs was 83% (35 of 42) in phase 1, 81% (34 of 42) in phase 2, and 90% (38 of 42) for combined phase 1 and 2 findings.

Mechanisms for cytoprotection by vitamin U from ethanol-induced gastric mucosal damage in rats

A comparison was made of the effects of a nonsulfhydryl compound, vitamin U (methylmethioninesulfonium chloride, MMSC), and a sulfhydryl compound, cysteine (Cys), with regard to the inducement of acute gastric mucosal damage in the presence and absence of N-ethylmaleimide (NEM), a sulfhydryl-blocking reagent. The effects of MMSC, Cys, or NEM on gastric mucin content were examined using a newly developed biochemical method. MMSC and Cys inhibited mucosal damage due to 50% ethanol. The preinjection of NEM had no effect on cytoprotection of prostaglandins, but prevented the effects of Cys and MMSC. MMSC and Cys increased surface mucin content but lessened that of deep mucin. NEM decreased surface mucin and increased deep mucin. It thus follows that sulfhydryl compounds accelerate the secretion of deep mucin and accumulate surface mucin. The cytoprotective mechanism of MMSC may thus be mediated by sulfhydryl compounds, and the increase in surface mucosal mucin may possibly be related to cytoprotection.

[Hepato-biliary excretion of water-soluble iodinated contrast medium shortly after abdominal angiography]

Thirty-nine patients underwent CT examination 15 to 30 min after abdominal angiography with ioxaglate. Gallbladder opacification was observed in 15 patients in the absence of clinical evidence of renal impairment. Among them, 14 patients revealed liver cirrhosis or chronic hepatitis, and one patient showed severe fatty liver on CT. The amount of contrast medium used varied from 70 ml to 310 ml (mean 180 ml). There was no significant relationship between visualization of the gallbladder and the total dose of ioxaglate or presence of liver dysfunction, which indicated that gallbladder opacification was not a rare phenomenon on CT shortly after abdominal angiography with a normal dose of ioxaglate. Gallbladder opacification on CT examination shortly after abdominal angiography shows that the hepatobiliary tract is important in the excretion of ioxaglate.

Gastric mucosal damage accompanying changes in mucin induced by histamine in rats

The present study was carried out to clarify the mechanism of histamine-induced gastric mucosal damage in rats. Following an injection of histamine (80 mg/kg), pH dropped within 30 min. and then recovered control value (pH = 4-5) 4 hr later. The decrease in mucosal mucin content and the appearance of haemorrhagic erosions followed the drop in pH. The recovery of mucosal mucin content preceded the healing of haemorrhagic erosions and pH recovery to the control level. Histamine also caused qualitative changes in corpus mucins. These qualitative changes induced by histamine were eliminated at 7 hr following the administration of histamine. It appears from the present results that increase in HCl and decrease in mucins induced by histamine bring about gastric damage.

Immunohistochemical study on choline acetyltransferase in the spinal cord of patients with amyotrophic lateral sclerosis

The authors developed a polyclonal antibody against a fusion protein containing 598 amino acids from a human choline acetyltransferase (ChAT) cDNA and 12 amino acids derived from an expression vector, and examined immunohistochemical reactivity for ChAT in large motor neurons (30 microns and more in somal minimal diameter) of the lumbar spinal cords of four patients with amyotrophic lateral sclerosis (ALS) and of four control cases. In controls, the number of large neurons included in the tissue with a total thickness of 100 microns ranged from 74 to 105 (average 87). About 60-90% (average 80%) of the neurons were positively stained in their perikarya with an anti-human ChAT antibody. In the cases of ALS, the number of large motor neurons was greatly reduced (25-60, average 38). About 4-13% (average 8%) were positively stained. These results indicate that not only large neurons are reduced in number, but also their positivity for ChAT is decreased in the anterior horn of ALS spinal cord.

Horizontal gene transfer: regulated expression of a tobacco homologue of the Agrobacterium rhizogenes rolC gene

A tobacco homologue (trolC) of the rolC gene of the Agrobacterium rhizogenes Ri-plasmid was cloned and sequenced from Nicotiana tabacum L. cv. Havana 425. The coding region of trolC is similar in sequence (69-87% for DNA and 54-89% for the deduced amino acid sequence) to rolC genes of the agropine, mannopine, and mikimopine strains of Ri-plasmids and the N. glauca rolC homologue. Southern analyses showed that trolC is encoded by a small gene family derived from the tomentosiformis ancestor of tobacco. This suggests that trolC resulted from an ancient transfer of DNA between A. rhizogenes and a progenitor of modern tobacco. Transcripts of trolC were detected in three morphologically distinct cultivars of tobacco. trolC mRNA accumulated in young leaves and shoot tips, but not in lower leaves and roots of mature plants. Accumulation of trolC mRNA in cultured leaf tissues was strongly down-regulated by auxin and induced by cytokinin. These results are of particular interest because they suggest that a gene of bacterial origin introduced during evolution can have a function in a modern plant.

[Early diagnosis of pancreatic carcinoma and utility of helical CT]

The pancreatic carcinoma, what is one of difficult carcinomas to treat. It is because the pancreatic carcinoma does infiltrate to external at early stage. However, it leads to increase of operation with significance to check it at early stage. Helical CT is developed in late years, and spread rapidly. This examination includes many clinical utilities. In early diagnosis of pancreatic carcinoma, improve former problems, and is thought that utility is high.

[MR imaging findings of the femoral marrow in myelodysplastic syndrome]

MR imaging of the femoral marrow was performed in 30 patients with myelodysplastic syndrome (MDS), 11 cases of which evolved to acute myeloid leukemia (AML). The MRI appearance was classified into five patterns: 1) fatty marrow; 2) faint signal; 3) nodular pattern; 4) heterogeneous infiltration; and 5) diffuse infiltration. For each type of MDS, MRI patterns of the femoral marrow were evaluated and compared with those in normal subjects as well as in patients with aplastic anemia. Signal intensity alteration, a low signal on T1-weighted SE image and a high signal on STIR image, began in the proximal femoral marrow almost symmetrically in patients with MDS. The area of abnormal signal intensity tended to gradually extend towards the distal portion of the femur as the disease progressed. MRI patterns of the femoral marrow correlated with marrow cellularity, and diffuse marrow infiltration was noted in patients with a more advanced type of MDS or with severe anemia. There were limitations to making an accurate diagnosis of the MDS type on the basis of the MRI pattern. Progression of the MRI appearance in the course of MDS was thought to be a sign suggesting evolution to AML. It was difficult to differentiate hypoplastic MDS from aplastic anemia, although the nodular pattern was commonly seen in the latter disease.

Localization of metastasis suppressor gene(s) for rat prostatic cancer to the long arm of human chromosome 10

To examine the role of human chromosome 10 in development of prostatic cancer, we introduced human chromosome 10 into highly metastatic rat prostatic cancer cells by microcell-mediated chromosome transfer. Microcell hybrid cells introduced with human chromosome 10 showed suppression of the metastatic ability to the lung to some extent without any suppression of tumorigenicity, although the tumor growth rate decreased slightly. To minimize the region that contains metastasis suppressive activity, the hybrid cells in metastasis foci of lung were established in culture and reanalyzed for portions of human chromosome 10 retained in the metastasis tissues. Cytogenetic and molecular analyses demonstrated that loss of the region between 10cen and D10S215 on human chromosome arm 10q was related to expression of the metastatic phenotype. These results demonstrate that the region between 10cen and D10S215 on human chromosome arm 10q contains at least one of the metastasis suppressor genes for rat prostatic cancer.

Missense mutation of rhodopsin gene codon 15 found in Japanese autosomal dominant retinitis pigmentosa

Heterozygous missense mutation in codon 15 of the rhodopsin gene was detected in a patient with autosomal dominant retinitis pigmentosa (ADRP), where a transition of adenine to guanine at the second nucleotide in codon 15 (AAT-->AGT), corresponding to a substitution of serine residue for asparagine residue (Asn-15-Ser) was detected. None of the remaining unrelated 42 ADRP, 24 autosomal recessive RP (ARRP) and 34 normal individuals had this alteration. Her funduscopic findings were sectorial in type similar to that of the patients with the same mutation found in an Australian pedigree (Sullivan et al., 1993). This study shows phenotypic similarities in patients with the same mutation of a different ancestry.

The effect on methamphetamine on the mRNA level for 14.3.3 eta chain in the human cultured cells

14.3.3 protein, a brain-specific protein, is an activator of tyrosine and tryptophan hydroxylases, key enzymes for biosynthesis of dopamine and serotonin. In this article, we describe cloning of cDNA for human brain 14.3.3 eta chain and expression of 14.3.3 eta chain mRNA in some human cultured cells. The cloned cDNA is 1730 bp long and contains 191 bp of a 5'-noncoding region, the complete 738 bp of coding region, and 801 bp of a 3'-noncoding region, containing three polyadenylation signals. This cDNA encoded a polypeptide of 246 amino acids (M(r) 28,196). Furthermore, using in situ hybridization histochemistry, the expression of mRNA for this protein was examined in the rat central nervous system. In situ hybridization histochemistry indicated that 14.3.3 eta chain mRNA is detected not only in the monoamine-synthetic neurons, but also in other neurons in the discrete nuclei, which synthesize neither cathecholamine nor serotonin. Northern blot analysis demonstrated that the addition of methamphetamine into the cultured medium increased the mRNA level for 14.3.3 eta chain in U-251 cells, but did not increase that of GFAP.