Oncogenic activation of the ret protooncogene in thyroid cancer

Recent studies have established that the ret protooncogene is involved in the development of thyroid tumors, including medullary and papillary thyroid carcinomas. Germ line mutations of the ret protooncogene were identified in multiple endocrine neoplasia (MEN) types 2A and 2B that share the clinical feature of medullary thyroid carcinoma and pheochromocytoma. MEN 2A mutations involved cysteine residues in the extracellular domain and induced disulfide-linked homodimerization of the Ret protein on the cell surface, leading to activation of its intrinsic tyrosine kinase. On the other hand, a single point mutation in the tyrosine kinase domain was found in MEN 2B, as well as in 30 to 40% of sporadic medullary carcinoma. This mutation also resulted in activation of Ret tyrosine kinase without the formation of its covalent homodimerization. Differences in the mechanisms of ret activation might account for the different phenotypes observed in MEN 2A and MEN 2B. In addition, somatic rearrangement of the ret protooncogene was frequently detected in papillary thyroid carcinoma, particularly from adult Europeans. A recent report demonstrated that the same rearrangement was observed in approximately 60% of papillary carcinomas of children from areas contaminated by the Chernobyl accident, suggesting that ret rearrangement was induced as a direct consequence of radiation exposure. In this review, I focus on the ret mutations detected in thyroid cancer and discuss the mechanisms of its oncogenic activation.

[A case of Sneddon syndrome]

Sneddon syndrome is a clinical entity that is characterized by livedo reticularis and cerebrovascular lesions and is considered to be a subtype of antiphospholipid antibody syndrome. Central retinal artery occlusion is one of the ophthalmic complications of this syndrome and its prognosis of visual acuity is generally poor. We report here a 50-year-old man with Sneddon syndrome who had recurrent central retinal artery occlusion with recovery of visual function after each episode.

Effects of caffeine on glandular stomach carcinogenesis induced in rats by N-methyl-N'-nitro-N-nitrosoguanidine and sodium chloride

The modifying effects of caffeine ingestion on glandular stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and sodium chloride (NaCl) were investigated in male Wistar rats. Animals were given a MNNG solution (100 ppm) as their drinking water and simultaneously fed a diet supplemented with 5% NaCl for 8 wk. They then received 0.25% caffeine solution (groups 1 and 3) or tap water (groups 2 and 4) as the drinking water, and were fed the NaCl diet (groups 1 and 2) or basal diet (groups 3 and 4) for the following 32 wk. Both caffeine and NaCl treatments exerted growth retardation effects, the suppression being stronger with caffeine than NaCl, and animals in group 1 (NaCl plus caffeine) showing the lowest body weight. The incidence of adenocarcinomas in the pylorus was significantly decreased in group 1 compared with the group 2 (NaCl) value (P < 0.05). The incidence of atypical hyperplasias in the fundus was also lower in group 1 than in group 2, although in both cases significantly higher (P < 0.05 and P < 0.01) than in group 4 (no treatment). These results were in good agreement with short-term assay findings whereby lipid peroxidation in the glandular stomach mucosa induced by 4% NaCl ingestion was inhibited by caffeine treatment. In group 3 (caffeine), caffeine intake by itself did not modulate glandular stomach tumour development. The results thus suggest that caffeine inhibits the gastric tumour promotion activity of NaCl in rats.

Influence of warm ischemia on isolation and primary culture of hepatocytes from rat liver for a hybrid artificial liver

To assess the possibility of using hepatocytes from ischemic liver, as a bioreactor of a hybrid artificial liver, we investigated the influence of warm ischemia on the isolation and culture of hepatocytes in rats. Warm ischemia was induced by clamping the liver hilus and the animals were divided into 3 groups according to the duration of ischemia: group A (no ischemia), group B (10 minutes) and group C (20 minutes). Hepatocytes were isolated by the collagenase perfusion method and cultured for 5 days. The yield and viability of the isolated hepatocytes were lower in group C. Rate of attachment was decreased as the duration of ischemia increased. There was no significant difference observed in functions in culture. Sufficient hepatocytes, as a bioreactor, can be isolated and cultured from warm ischemic liver within 10 minutes. Though the number of available hepatocytes were diminished, hepatocytes procured from longer warm ischemic liver could be utilized as a bioreactor.

Scaling of transepithelial potential difference in the mammalian trachea

Tracheal epithelia of different mammalian species differ widely with regard to the relative rates of Na+ absorption and Cl- secretion. However, the short circuit current, a measure of total ion transport, appears to be consistently greater in large than in small mammals. Thus, we hypothesized that the in vivo tracheal electrical potential difference (PD) would vary among species as a function of body mass (M). To test this hypothesis we measured PD in ten mammalian species that ranged 1000-fold in mass. The results in mV (mean +/- SE, lumen negative) were: 11.4 +/- 1.0 in mice; 11.6 +/- 1.2 in gerbils; 12.9 +/- 1.4 in rats; 19.3 +/- 0.9 in guinea pigs; 27.2 +/- 2.2 in ferrets; 23.0 +/- 1.6 in cats; 27.0 +/- 0.6 in rabbits; 32.5 +/- 2.6 in dogs; 37.0 +/- 1.9 in sheep; and 49.0 +/- 3.3 in pigs. Log-log correlation analysis of mean PD (in mV) and M (in kg) yielded PD = 20.9 M0.19 (r = 0.96, P < 0.001). Analysis of published short circuit current (SCC, in microA/cm2) data revealed a similar relationship: SCC = 38.2 M0.21. Thus, the transepithelial electrical potential and active charge transport by the tracheal epithelium are allometric variables that may have direct physiological significance. These results raise questions regarding the importance of net osmotic solute and water transport across the tracheal epithelium.

A case of adenocarcinoma arising within a urethral diverticulum diagnosed only by the surgical specimen

We report an extremely rare case of a 50-year-old woman with an adenocarcinoma arising within a urethral diverticulum. She could not be diagnosed correctly before operation and the microscopic pathological examination of the surgical specimen was the only indication showing the cancer origin.

Clinical evaluation of 430 MHz microwave hyperthermia system with lens applicator for cancer therapy

The clinical efficacy of a microwave (MW) hyperthermia system using an electric-field converging (lens) applicator is evaluated for 42 malignant tumours with a maximum tumour depth of less than 7 cm. The mean of the maximum, average and minimum tumour temperature of the 42 tumours are 44.5, 42.5 and 40.7 C, respectively. The thermal parameters are higher for tumours in the chest, abdominal walls and hip than for those in the neck, groin and extremities. No apparent difference in thermal parameters according to the depth of tumour is shown. Of 40 tumours treated by hyperthermia in combination with radiotherapy, 20 (50%) showed complete regression, 14 (35%) showed partial regression, and six (15%) showed no change. This phase I and II study indicates clinical feasibility of the newly developed MW heating apparatus, and strongly suggests the usefulness of thermoradiotherapy in the treatment of localised superficial and subsurface malignancies.

Squamous cell carcinoma of the uterine cervix: radiation therapy for patients aged 70 years and older

PURPOSE

To evaluate the usefulness of radiation therapy for elderly patients with squamous cell carcinoma of the uterine cervix.

MATERIALS AND METHODS

Two hundred ninety-three patients with squamous cell carcinoma of the uterine cervix underwent external pelvic irradiation and three sessions of low-dose-rate intracavitary irradiation. One hundred twenty-six patients were aged 70 years or older (elderly group), and 167 patients were aged 69 years or younger (younger group). Survival rates, pattern of failure, local control rates, and complications for the two groups were compared.

RESULTS

The 5-year, cause-specific survival rates for the elderly group with stage I, II, III, or IV disease were 100%, 81%, 73%, and 54%, respectively. Corresponding rates for the younger group were 100%, 92%, 74%, and 32%. Differences in survival curves, patterns of failure, recurrence rates, and incidences of radiation complications for the two groups were not statistically significant.

CONCLUSION

Age did not influence the effectiveness of radiation therapy for the elderly patients.

A kinetic study of the endolymphatic sac epithelial cells

The kinetics of S-phase (the period of DNA synthesis) cells in the endolymphatic sac (ES) was investigated by immunohistochemical methods. A monoclonal antibody against 5 bromo 2'-deoxyuridine (BrdUrd) was used. After administration of BrdUrd i.p., guinea pigs were sacrificed with acid formalin at designated survival times until 28 days, and the decalcified temporal bones were examined immunohistochemically. After survival for 30 min, scattered cells labelled with an anti-BrdUrd antibody were detected within the ES, whereas they were not found any other part of the inner ear. Labelled cells were observed more frequently in the rugose portion than in the other portion of the ES. At 3 days after BrdUrd labelling, increased numbers of labelled cells were detected. Labelled mitoses could be observed in the epithelium after long survival times. Our results show that the epithelial cells of the ES in adult animals turn over in the steady-state.

DNA analysis in hereditary dentatorubral-pallidoluysian atrophy: correlation between CAG repeat length and phenotypic variation and the molecular basis of anticipation

Hereditary dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disease with variable clinical phenotypes. Progressive ataxia, choreoathetosis, and dementia are the main clinical features of adult-onset cases, whereas the main feature in juvenile-onset DRPLA is progressive myoclonus epilepsy. Earlier onset is apparent in successive generations (anticipation). The molecular abnormality underlying DRPLA is an expanded, unstable CAG trinucleotide repeat on chromosome 12p. We analyzed 71 DNA samples obtained from 12 Japanese DRPLA pedigrees that included 38 affected individuals. Normal alleles had 7 to 23 repeats, DRPLA alleles 53 to 88 repeats. DRPLA alleles also were detected in five asymptomatic family members. Patients with juvenile onset had significantly larger repeats than did those with adult onset, and there was a significant negative correlation between CAG repeat length and age at onset. In 80% of the paternal transmissions, there was an increase of more than five repeats, whereas all the maternal transmissions showed either a decrease or an increase of fewer than five repeats. There was a significant correlation between father-child differences in repeat length and differences in age at onset. The analysis of CAG repeat length is a reliable diagnostic test for DRPLA and is of value for the presymptomatic detection of individuals at risk. The expansion of CAG repeats is important in phenotypic variation and anticipation. In addition, the sex of the transmitting parent has a significant effect on the molecular mechanism of anticipation.

Multiple saccular aneurysm formation in a patient with bilateral coronary artery fistula: a case report and review of the literature

We describe a case of bilateral coronary artery fistula originating from the left anterior descending and right coronary arteries which showed multiple saccular aneurysm formation. Although saccular aneurysm formation in patients with bilateral coronary artery fistula is extremely rare, only 3 similar cases having been reported before, it shows two distinctive features upon coronary angiography: multiplicity and origin in the left fistulous coronary artery.

Angiomyxoid tumour in the renal peripelvic tissues with features of aggressive angiomyxoma

A case of angiomyxoid tumour in the renal peripelvic soft tissue of a 45 year old woman is reported. The encapsulated tumour, measuring 12 x 9 x 6 cm, was solid and firm. The cut surface revealed a yellowish-white, gelatinous, and glistening tumour. Histologically, the tumour was composed of loosely textured spindle and stellate cells with prominent blood vessels of variable calibre. The tumour cells stained strongly for vimentin. These findings strongly resemble those associated with aggressive angiomyxoma in the vulva and perineum.

Fine structures of utricle of developing chick embryo exposed to 2G gravity

Utricular otoconia of the chick embryos incubated under continuous 2G load were examined under a scanning electron microscope. Morphological changes were confined to the process of otoconial formation and the otoconial size. Otoconial formation was remarkably delayed in the utricle of 2G centrifuged chick embryo. Giant otoconia, which sometimes amounted to over 100 microM in length, existed along the marginal zone of the utricular otolithic membrane. These results indicate that the 2G state influences the otoconical formation.

Effect of cigarette smoke on the mutagenic activation of various carcinogens in hamster

Male Syrian golden hamsters were exposed for 1 or 2 weeks to smoke produced by commercial non-filter cigarettes for 5 consecutive days in a Hamburg type II smoking machine. Postmitochondrial fractions (S9) prepared from the liver, lungs, and pancreas were used in the Ames liquid incubation assay, in order to assess the effect of cigarette smoke (CS) on the metabolic activation of four groups of procarcinogens. The mutagenic activities of five heterocyclic amines on strain TA98 in the presence of liver S9 mix were induced up to 3.7 times above controls including sham smoke control, while no significant alteration of mutagenicity was observed with 3'-hydroxymethyl-N,N-dimethyl-4-aminoazobenzene and benzo[a]pyrene on TA98 or with N-nirosobis(2-oxopropyl)amine (BOP) on TA100. A similar stimulation of metabolic activation was also observed for 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) with S9 from the lungs but not from the pancreas. The mutagenic potential of 11 carcinogens including aflatoxin B1 (AFB1) and two other heterocyclic amines was also examined using liver S9 from male hamsters pretreated with phenobarbital (PB) or 3-methylcholanthrene (MC). The numbers of revertant colonies were much higher (2-20-fold) in the presence of MC-treated liver S9 than in the presence of PB-treated liver S9, except in the case of AFB1 which showed a higher mutagenicity with PB-induced S9. 7,8-Benzoflavone considerably inhibited the activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and Trp-P-1 in the presence of either untreated, MC- or CS-treated liver S9, whereas metyrapone was totally lacking this effect, indicating that cytochrome P450(CYP)1A1/1A2 isoforms of hamster liver are predominantly involved in the metabolic activation of these carcinogens. CS exposure of hamsters might selectively induce hepatic CYP1A2 which cannot activate BOP. Consequently, the present findings could explain, in part, the anticarcinogenic effect of CS on BOP-induced pancreatic tumors in hamsters. The findings further support the idea that CS markedly stimulates the metabolic activation of food-derived carcinogens, which may contribute to the overall carcinogenic effects of cigarette smoking.

Influence of Warm Ischemia on Isolation and Primary Culture of Hepatocytes from Rat Liver for a Hybrid Artificial Liver

To assess the possibility of using hepatocytes from ischemic liver, as a bioreactor of a hybrid artificial liver, we investigated the influence of warm ischemia on the isolation and culture of hepatocytes in rats. Warm ischemia was induced by clamping the liver hilus and the animals were divided into 3 groups according to the duration of ischemia: group A (no ischemia), group B (10 minutes) and group C (20 minutes). Hepatocytes were isolated by the collagenase perfusion method and cultured for 5 days. The yield and viability of the isolated hepatocytes were lower in group C. Rate of attachment was decreased as the duration of ischemia increased. There was no significant difference observed in functions in culture. Sufficient hepatocytes, as a bioreactor, can be isolated and cultured from warm ischemic liver within 10 minutes. Though the number of available hepatocytes were diminished, hepatocytes procured from longer warm ischemic liver could be utilized as a bioreactor.

Crossed ureteral ectopia with an ectopic blind-ending ureter

A rare case of multiple urological anomalies is presented. The chief complaint of the patient, a 12-year-old girl, was urinary incontinence. Radiologic and endoscopic examinations revealed that the patient had a normal left kidney and ureter, a left ectopic blind-ending ureter that opened near the neck of the bladder, and right complete double ureters with an ectopic orifice that opened on the left of the external urethral meatus. This orifice was responsible for her urinary incontinence. Right ureteroneocystostomy was performed and the incontinence was cured. An attempt was made to explain the embryological origin of the anomalies observed in this case. We postulated that during development, on the left, there were three ureteral buds on the mesonephric duct. The first bud was at the normal position and drained the left kidney in a normal manner. The second bud was cranial from the normal position on the mesonephric duct and was associated with growth in an abnormal direction. This bud made contact with the upper portion of the right metanephric mass. The last bud grew between the two aforementioned buds. This bud was not draped by the metanephric mass and became the blind-ending ureter. On the right, one ureteral bud was located on the mesonephric duct and it made contact with a metanephric mass that became the right kidney. The upper part of the right kidney was drained by the ureter that had originally been located on the left mesonephric duct. This condition should be termed crossed ureteral ectopia rather than crossed renal ectopia, since the ureter was the structure that crossed.

Inhibition of growth and cysteine proteinase activity of Staphylococcus aureus V8 by phosphorylated cystatin alpha in skin cornified envelope

The activity of a cysteine proteinase purified from Staphylococcus aureus V8 (SAV8) was inhibited by phosphorylated cystatin alpha (P-cystatin alpha) and by purified cornified envelope protein of newborn rat, a conjugated form of P-cystatin alpha. Immunohistochemical analysis demonstrated a marked decrease in P-cystatin alpha content in cornified envelope treated with sphingosine. The inhibition of papain activity by proteins from sphingosine-treated skin was much weaker than that exerted by proteins from the untreated skin. The suppression of SAV8 colony formation inoculated on the sphingosine-treated skin was examined. Colony formation on the sphingosine-treated skin was enhanced compared to that on normal skin. These findings suggest that P-cystatin alpha in the cornified envelope may have a bacteriostatic barrier function against bacterial infection, such as that with SAV8.

Uniquely higher incidence of isolated or combined deficiency of band 3 and/or band 4.2 as the pathogenesis of autosomal dominantly inherited hereditary spherocytosis in the Japanese population

To clarify the pathogenesis of hereditary spherocytosis (HS), red cell membrane protein components were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with a 3.5-17% exponential gradient according to the method of Fairbanks et al. and of Laemmli in 47 HS cases from 32 unrelated Japanese families. The relative contents of each membrane protein fraction, which was stained by Coomassie blue, were expressed as their ratios to those of total membrane proteins. The density of each band of red cell membrane proteins in 47 HS patients was compared to that in 10 normal controls or in 4 high-reticulocyte controls. Various isolated or combined deficiencies of membrane proteins in these HS patients were detected by identifying the amounts of membrane proteins, which were > 1 S.D. (91%) or 2 S.D. (53%) of the mean values of normal controls, and > 1 S.D. (100%) or 2 S.D. (98%) of those of high-reticulocyte controls. Contrary to the commonly held belief that most of the autosomal dominantly-inherited HS demonstrate isolated or combined deficiency of ankyrin (ANK) and/or spectrin (SP), a much lower incidence of isolated or combined deficiency of SP and/or ANK was observed in these Japanese HS patients; 19% (> 1 S.D.) or 12% (2 S.D.) compared to normal controls, or 2% (1 S.D.) or 4% (2 S.D.) compared to high-reticulocyte controls. Instead, the incidence of isolated or combined deficiency of band 3 (B3) and/or band 4.2 (B4.2) was markedly elevated in these Japanese HS patients; 50% (1 S.D.) or 39% (2 S.D.) compared to normal controls, or 78% (1 S.D.) or 88% (2 S.D.) compared to high-reticulocyte controls. Other combined deficiencies were also observed, but the incidence was much lower. Therefore, distinct characteristics, i.e., higher incidence of isolated or combined deficiency of B4.2 and/or B3 with much lower incidence of ANK and/or SP deficiency, were observed in Japanese HS patients.

Study on the carcinogenicity of tannic acid in F344 rats

The carcinogenicity of tannic acid, a compound that is used as a food additive, a clarifying agent and a refining agent, was examined in F344 rats of both sexes. Tannic acid was dissolved in distilled water at concentrations of 0.25 and 0.5%. The doses were selected on the basis of results from a 13-wk subchronic study. Groups of 50 male and 50 female rats were given one of these solutions ad lib. as their drinking water for up to 2 yr. The mean body weights of the treated males were essentially comparable with those of the controls, whereas treated females had lower mean body weights than the control group. A variety of tumours developed in all groups, including the control group, but all the neoplasms were histologically similar to those known to occur spontaneously in this strain of rats, and no statistically significant increase in the incidence of any tumour was found in the treated groups of either sex. Thus, it is concluded that, under the conditions of the experiment, tannic acid has neither carcinogenic potential in F344 rats nor modifying effects on spontaneous tumour development.

Intrafamilial clustering of genotypes of hepatitis C virus RNA

Hepatitis C virus (HCV)-RNA in the blood was measured by polymerase chain reaction (PCR) in 37 subjects from eight families in which 2 or more persons tested seropositive for antibodies against C100-3 or CP9. HCV-RNA was positive in 17 of 37 subjects. Two or more HCV-RNA-positive subjects were observed in six of the families. Intrafamilial HCV infection was studied by determining the HCV-RNA type (I, II, III or IV) by PCR using type-specific primers. In two families, all of the subjects showed type III infection, and in three other families, all of the subjects showed type II infection, with different types of HCV infections being observed in only one family. The HCV type was uniform in all but one. These findings suggest a possibility of intrafamilial infection between husbands and wives and between members of the same household.

Biosynthesis of a novel polysaccharide by Acetobacter xylinum

An Acetobacter xylinum adapted to a medium containing N-acetylglucosamine (GlcNAc) has been used to prepare a novel polysaccharide containing residual GlcNAc in cellulose. The maximum amount of incorporation was found to be 4 mol% in cellulose, when a mixed medium containing 1.4% glucose (Glc) and 0.6% GlcNAc was used for the culture of A. xylinum. The resulting polysaccharide was lysozyme-susceptible. The aminosugar residue incorporated into bacterial cellulose was found to be only GlcNAc, even if galactosamine (GalN) and glucosamine (GlcN) were applied, whereas there was little effect by mannosamine (ManN). As the major component of the resulting polysaccharide was Glc residues, even if the only carbon source in the culture medium was GlcNAc, it was suggested that there must be several enzyme systems to convert GlcNAc into Glc in the bacteria. Several ammonium salts were also found to be effective for the incorporation of GlcNAc residues when the incubation system was converted to rotatory and aerobic incubation from static incubation. The amount of residual GlcNAc was remarkably increased by the addition of lysozyme-susceptible phosphoryl-chitin (P-chitin) and increased slightly with addition of P-chitin that was less lysozyme-susceptible. However, little effect was found on addition of highly substituted P-chitin.

Nucleotide sequence of RNA 1, the largest genomic segment of rice stripe virus, the prototype of the tenuiviruses

The complete nucleotide sequence of RNA 1, the largest genomic segment of rice stripe virus (RSV), was determined using two sets of overlapping cDNA clones. RNA segment 1 comprises 8970 nucleotides and on the viral complementary sequence has a single long open reading frame coding for a protein of 2919 amino acids with an estimated M(r) of 336860. Amino acid sequence comparisons of the putative protein indicated strong homology (30% amino acid identity over about 1500 residues) with the L protein of the genus Phlebovirus of the Bunyaviridae, but no detectable similarity with other members of the Bunyaviridae. However, weak similarity was detected with the L protein of Tacaribe arenavirus. The highly homologous sequence domain includes the conserved motifs of the putative RNA-dependent RNA polymerase. The data presented here, along with previous work clearly show significant similarities in genome organization, structure and expression between RSV and members of the genus Phlebovirus of the Bunyaviridae. Taken together, we propose that tenuiviruses should be included in the Bunyaviridae under the genus Tenuivirus.