Three-dimensional organization of lymphatics in the dog small intestine: a scanning electron microscopic study on corrosion casts

Casts of the lymphatics of the canine small intestine were made by direct injection of a low viscosity methacrylate resin into a large lymphatic in the submucosal layer, and observed under a scanning electron microscope. The lymphatics started with rod-like central lacteals in the villi of the jejunum and leaf-like ones in those of the ileum. The bases of the lacteals were connected by slender lymphatics forming a three-dimensional network, tentatively called the "superficial lamina propria lymphatic plexus". From this plexus, a few straight branches descended through the lamina propria to drain into a well developed "deep lamina propria lymphatic plexus", which was extended two-dimensionally closely above the lamina muscularis mucosae. From this plexus, a few short lymphatics extended and penetrated the muscularis mucosae and drained into the "superficial submucosal lymphatic plexus", a coarse mesh work of thick lymphatics. From this plexus, a few slender lymphatics descended to drain into a second lymphatic plexus, called the "deep submucosal lymphatic plexus", which extended two-dimensionally on the circular muscle layer. This deep submucosal plexus was a coarse network of thick knotty lymphatics. A large collecting lymphatic was occasionally seen running through the mesh. The tunica muscularis contained tubular lymphatics extending horizontally parallel to the muscle fiber, both circular and longitudinal.

Transient increase of cyclic AMP induced by glutamate in cultured neurons from rat spinal cord

We demonstrated that glutamate increased the cyclic AMP level in cultured neurons from rat spinal cord. A bath application of glutamate (300 microM) elicited a rapid increase of the cyclic AMP concentration reaching a level three times as high as the basal level in approximately 3 min, and its content then decreased to the control level in 15 min. The increase was not observed in a Ca(2+)-free medium and was inhibited by an antagonist of NMDA receptors or a voltage-sensitive Ca2+ channel blocker. Preincubation with W7 also inhibited the glutamate-evoked cyclic AMP increase. NMDA, aspartate, and high-K+ conditions also induced a cyclic AMP increase; however, a decreasing phase did not follow. The decreasing phase was observed when (2S,1'S,2'S)-2-(carboxycyclopropyl)-glycine, a potent agonist for metabotropic glutamate receptors, was combined with NMDA. These results suggest that the cyclic AMP increase is mediated by a Ca2+ influx via both NMDA receptors and voltage-sensitive Ca2+ channels followed by an activation of the Ca2+/calmodulin system, and the decreasing phase observed in the case of glutamate exposure is due to the activation of the metabotropic glutamate receptors.

Neurotoxicity of acromelic acid in cultured neurons from rat spinal cord

Acromelic acid A, which contains the kainic acid structure in its molecule, is known to cause selective damage of interneurons in the rat lower spinal cord. In the present study, the potent neurotoxicity of acromelic acid A was demonstrated in cultured rat spinal neurons in terms of the activity of lactate dehydrogenase that was released from degenerated neurons into the culture medium. Acromelic acid A increased the lactate dehydrogenase activity in time- and concentration-dependent manners, and its EC50 was about 2.5 microM, which was much lower than that of kainic acid (70 microM) and (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (EC50; 11 microM). The maximum level of lactate dehydrogenase released by acromelic acid A was quite similar to that by kainic acid, but was about twice the level produced by (RS)-alpha-3-hydroxy-5-methyl-4-isoxazolepropionic acid. Exposure to acromelic acid A caused release of L-glutamate from the cells into the medium; however, the concentration of L-glutamate released was far below the level for inducing the neurotoxic effects. The neurotoxicity of 10 microM acromelic acid A was almost completely inhibited by 30 microM 6-nitro-7-sulphamoylbenzo(F)quinoxaline-2,3-dione and 6-cyano-7-nitroquinoxaline-2,3-dione, potent antagonists for non-N-methyl-D-aspartate receptors, but was partly (35%) reduced by 30 microM dizocilpine maleate. In cultured hippocampal neurons, the toxicity of acromelic acid A was significantly less effective (EC50: 18 microM) than that in spinal neurons, whereas the toxicity of kainic acid was almost the same in both neurons. These results suggest that acromelic acid A directly activates non-N-methyl-D-aspartate receptors on the cultured spinal neurons to induce neuronal death. A new type of non-N-methyl-D-aspartate receptors which is specific to acromelic acid A is suggested to be present at least in spinal neurons.

[Experimental and clinical study on intraoperative local infusion chemotherapy (ILIC) for advanced gastric carcinoma]

An intensive chemotherapy combined with surgery, termed "intraoperative local infusion chemotherapy (ILIC)", was devised. The ILIC procedure is to infuse 50 mg of cisplatin through the feeding artery to the tumor, which has been isolated from blood flow by clamping the stomach and blood vessels, before radical surgery. An experiment in dogs showed considerable free Pt transfer into thoracic lymph after ILIC. Sum total Pt in the thoracic lymph after ILIC (294.5 micrograms/3 h) was 4.3 times that after IV administration (68.3 micrograms/3 h). In ILIC, AUC of free Pt in the thoracic lymph was about 5.8 times that in peripheral blood. ILIC was applied in 24 advanced gastric cancer patients, consisting of 6, 2, 4 and 12 in pTNM stage II, IIIA, IIIB and IV, respectively. Pt concentration of the tissues was high in the tumor (23.22 micrograms/g) and the regional lymph nodes (2.95 micrograms/g) compared to that in the serum (0.45 microgram/ml). The survival rate (Kaplan-Meier) in the ILIC patients was significantly higher than that of control patients (matched pair method) from among patients treated by surgery alone. No fatal complications were encountered in any patient treated by ILIC.

Expression of the multidrug resistance-associated protein (MRP) gene in non-small-cell lung cancer

We examined the levels of expression of the multidrug resistance-associated protein (MRP) gene quantified by Northern blot analysis in comparison with those of the MDR1 gene determined by reverse transcription-polymerase chain reaction (RT-PCR) in 104 non-small-cell lung cancer (NSCLC) specimens [59 adenocarcinoma (Ad), 40 squamous cell carcinoma (Sq), four large cell carcinoma (La) and one adeno-squamous carcinoma (AdSq)]. Thirty-three (31.7%) of the 104 NSCLC expressed the MRP gene at various levels. The NSCLC showing high (++) levels of MRP gene expression (19 out of 33, 57.6%) were predominantly squamous cell carcinomas (Ad, 5; Sq, 13; La, 1) (P < 0.05). Six of the eight NSCLCs expressing high levels of MRP mRNA and no MDR1 (MRP ++, MDR1-) were squamous cell carcinomas. Sixty-one of the 104 NSCLC patients received chemotherapy with MRP-related anti-cancer drugs [vindesine (VDS) and etoposide (VP-16)]. Twenty-three patients (37.7%) with tumour expressing high or moderate levels of MRP showed significantly worse prognoses than those with non- or low-MRP-expressing tumours (P < 0.05). These results suggest that the level of MRP gene expression is related to the histopathology and prognosis of NSCLC.

Successful treatment of invasive thoracopulmonary mucormycosis in a patient with acute lymphoblastic leukemia

BACKGROUND

Pulmonary mucormycosis associated with hematologic malignancy is an uncommon, but important opportunistic fungal pneumonia that is usually a fatal infection. Only a few survivors of pulmonary mucormycosis have been reported.

METHODS

A case report of invasive thoracopulmonary mucormycosis during remission-induction therapy for acute lymphoblastic leukemia and a review of the literature are presented.

RESULTS

The fungal lesions extended to both lungs, the left ribs, and intercostal muscles. Percutaneous needle biopsy and immunostaining of the fungal hyphae established the diagnosis of thoracopulmonary mucormycosis. The patient was treated with granulocyte-colony stimulating factor (G-CSF) and intravenous amphotericin B for 9 weeks and the lesions in the right lung disappeared. Left pneumonectomy and partial resection of the chest wall were later performed. The left lung was grossly necrotic and contained a large cavity and bronchopulmonary fistula. Thereafter, antileukemic therapy was resumed and completed without recurrence of mucormycosis or leukemia.

CONCLUSIONS

In the management of mucormycosis, the addition of G-CSF to the conventional treatment may substantially improve outcome.

Inhibitors of cGMP-dependent protein kinase block senescence induced by inactivation of T antigen in SV40-transformed immortal human fibroblasts

Immortal human fibroblasts isolated following transfection with thermolabile simian virus 40 T antigen lost division potential upon shift up in temperature due to heat inactivation of the antigen. Such cells showed a concomitant change in the distribution of a mortality marker, mortalin, from a juxtanuclear cap like distribution of immortal cells to a uniform cytosolic distribution of mortal cells. We made an attempt to modulate the above inducible system of cellular senescence using various protein kinase inhibitors. Among the indolocarbazole type inhibitors tested, only KT5823, defined as a specific inhibitor of cGMP-dependent protein kinase, blocked the loss of division potential as determined by cell growth and colony forming ability. This inhibitor also prevented the above change in mortalin distribution due to temperature shift. In addition, the isoquinoline sulfonamide derivatives H8, H9, H88 and H89, all shown to inhibit cGMP-dependent protein kinase, suppressed the senescence. Inhibitors specific to other types of protein kinases, protein phosphatases or tyrosine kinases tested had no effect. Since there was no difference between the effective and non-effective inhibitors in their effects on cell cycle progression, cell cycle arrest by itself cannot account for the above phenomenon. These results suggest that a signaling pathway possibly mediated by cGMP-dependent protein kinase is involved in the induction of cellular senescence.

Scanning tunneling microscopic study of osmium-impregnated collagen

The vapor-phase osmium impregnation method was applied to increase the conductivity of the collagen specimens used in scanning tunneling microscopy (STM), since the application of STM to biological materials has been limited by the poor conductivity, irregular sample geometry, and instability of these materials. The impregnation method was applied to collagen fibrils attached to highly oriented pyrolytic graphite, and the STM images obtained were compared with those of routinely processed uncoated specimens. The osmium-impregnated collagen fibrils showed a periodicity of about 67 nm, which was also observed on the negative-stained specimens by transmission electron microscopy. In addition, the periodicity of 3.1 nm, which corresponded to the helical cycle of the 3 alpha-chains within collagen, was clearly demonstrated by STM. Moreover, the comparative observations of collagen specimens without osmium impregnation disclosed the left-handed helical structure with a periodicity of 3.1 nm in a single collagen filament.

Extraordinarily high eosinophilia and elevated serum interleukin-5 level observed in a patient infected with Paragonimus westermani

OBJECTIVE

Although eosinophilia is one of the typical clinical features of some helminth infections, the degree of eosinophilia in helminthiasis is usually 10% to 30% with a total white blood cell count of 10,000 to 20,000/mm3. Here we report a case of extraordinarily high eosinophilia (91%; absolute eosinophil count, 84,000/mm3) caused by Paragonimus westermani infection. To determine the mechanisms of eosinophilia, the levels of several eosinophilopoietic cytokines in the patient's sera were measured during the course of treatment.

METHODS

Serum levels of three cytokines, granulocyte-macrophage colony-stimulating factor, interleukin-3 (IL-3), and IL-5 were measured by enzyme-linked immunosorbent assay using commercial kits or our own assay system for IL-5.

RESULTS

Although the kinetic changes of IL-5 correlated well with eosinophilia, the serum IL-3 level remained below the detection level throughout the period examined. Although the granulocyte-macrophage colony-stimulating factor level was twofold to threefold higher than the normal level, its kinetics did not parallel the degree of eosinophilia.

CONCLUSIONS

These results show that Paragonimus westermani infection can induce an extraordinarily high level of eosinophilia with an associated increase in IL-5 production. Immunoserologic diagnosis for parasitic diseases should be included in the differential diagnosis of eosinophilia.

Chromosomal localisation of a Y specific growth gene(s)

Although a Y specific growth gene(s) has been postulated in the Yq11 region, the precise location has not been determined. To localise the growth gene(s), we correlated genotype with stature in 13 Japanese and four European non-mosaic adult male patients with a partial Yq deletion. Fourteen patients preserving the region between DYS11 and DYS246 did not have short stature (11 Japanese, 165-180 cm; three Europeans, 165-173 cm) whereas the remaining three patients with the region deleted had short stature (two Japanese, both 159 cm; one European, 157 cm). The results suggest that the region defined by DYS11 at interval 5C and by DYS246 at interval 5D may be the critical region for the Y specific growth gene(s).

Turner syndrome and female sex chromosome aberrations: deduction of the principal factors involved in the development of clinical features

Although clinical features in Turner syndrome have been well defined, underlying genetic factors have not been clarified. To deduce the factors leading to the development of clinical features, we took the following four steps: (1) assessment of clinical features in classic 45,X Turner syndrome; (2) review of clinical features in various female sex chromosome aberrations (karyotype-phenotype correlations); (3) assessment of factors that could lead to Turner features; and (4) correlation of the clinical features with the effects of specific factors. The results indicate that the clinical features in 45,X and in other female sex chromosome aberrations may primarily be determined by: (1) degree of global non-specific developmental defects caused by quantitative alteration of a euchromatic or non-inactivated region; (2) dosage effect of a pseudoautosomal growth gene(s), a Y-specific growth gene(s), and an Xp-Yp homologous lymphogenic gene(s); and (3) degree of chromosome pairing failure in meiocytes that are destined to develop as oocytes in the absence of SRY. 1991; Grumbach and Conte 1992). However, the pertinent factors have not been determined to date. The method to clarify the factors responsible for the development of the Turner phenotype can be broken down into the following steps: (1) assessment of clinical features in classic 45,X Turner syndrome; (2) review of clinical features in various female sex chromosome aberrations (karyotype-phenotype correlations); (3) assessment of factors that could lead to Turner features; and (4) correlation of the clinical features with the effects of specific factors. If the clinical features in 45,X and in other female sex chromosome aberrations are explained by the effects of specific factors, it can be said that such factors contribute to the development of Turner features. In this paper, we take each of the above steps, and propose the principal factors involved in the development of clinical features in Turner syndrome.

A possible mechanism for the hypoxia-hypoglycemia-induced release of excitatory amino acids from cultured hippocampal astrocytes

In order to elucidate the mechanism of release of excitatory amino acid (EAA) induced by hypoxia-hypoglycemia (in vitro ischemia) from cultured hippocampal astrocytes, we compared the EAA release by in vitro ischemia with those by other treatments. The EAA release induced by in vitro ischemia treatment was rapid and reversible. The amount of released aspartate was comparable to that of glutamate, although the endogenous content of aspartate was one sixth that of glutamate. High-K (100 mM) treatment and the addition of 5 mM NaCN induced a rapid EAA release and the glutamate release was much greater than aspartate. Addition of 5 mM iodoacetate, a glycolysis inhibitor, induced a slow EAA release, and the amount of released aspartate was much higher than that of glutamate. On the other hand, the in vitro ischemia treatment and the addition of 5 mM NaCN induced only 20% reduction in ATP content for initial 5 min, whereas the addition of 5 mM iodoacetate induced a marked reduction. Our data suggest that ischemia-induced EAA release from astrocytes is a complex process in which local energy failure, inhibition of glycolysis, and depolarization of the cell membrane are involved.

Immunohistochemical analysis of dendritic/Langerhans cells in thyroid carcinomas

Recent immunohistochemical investigations of thyroid carcinomas have revealed that dense infiltration by dendritic cells (DCs) is correlated with a favorable prognosis. The present study was done to clarify the frequency and characteristics of DC infiltration in thyroid carcinomas, and also cytokines associated with DC maturation and migration. Compared with follicular carcinomas, papillary carcinomas contained significantly higher numbers of DCs, interleukin (IL)-1 alpha- and tumor necrosis factor (TNF)-alpha-positive cells, and cells positive for two TNF-alpha receptors (p60 and p80). The centers of cancer nodules had large numbers of CD1a- and CD1c-positive DCs suggesting that they were Langerhans cells, whereas the periphery of cancer nodules and inflamed surrounding thyroid tissues had numerous CD1b-, L-M2- and X-12-positive DCs suggesting that they were interdigitating cells, as well as many CD1a- and CD1c-positive DCs. Neoplastic cells of papillary carcinomas were more frequently reactive with antibodies against IL-1 alpha and TNF-alpha than those of follicular carcinomas, and a good correlation between their immunoreactivity and the frequency of DCs was found. These data suggest that cytokines such as IL-1 alpha and TNF-alpha released from carcinoma cells and cells in the cancer stroma may regulate the infiltration and maturation of dendritic/Langerhans cells, and that this process may be better preserved in papillary than in follicular carcinomas.

A 10-year experience of intraoperative radiotherapy for gastric carcinoma and a new surgical method of creating a wider irradiation field for cases of total gastrectomy patients

PURPOSE

To improve the prognosis of gastric cancer, radical surgical resection with extensive lymph node dissection plus intraoperative radiation therapy (IORT) was tried in our clinic. In addition, a new operative procedure was created to obtain wider irradiation field for total gastrectomy patients.

METHODS AND MATERIALS

A total of 183 gastric cancer patients who underwent radical gastrectomy with or without IORT from August 1983 to July 1992 were retrospectively evaluated. The patients were divided into two groups: group 1 consisted of 58 patients who underwent radical operation plus IORT. A single dose of 28 to 30 Gy was delivered around the celiac axis with an electron beam of 12 MeV. Group 2, our historical control group, which showed no difference in age, sex and stage, consisted of 120 patients who underwent only radical surgery. In addition, a new method of total gastrectomy with IORT after mobilization of the tail and body of the pancreas was devised to get wider irradiation field for advanced gastric cancer.

RESULTS

Of the Stage II gastric cancer patients, all the 11 patients of group 1 are alive, whereas in group 2, the 4-year and the 8-year survival rates were 60% and 48%, respectively. In Stage III patients, the 8-year survival rate of group 1 was 55% vs. 35% in group 2. As for Stage IV patients, the 5-year survival rate of group 1 was 12% and that of group 2 was 13%.

CONCLUSION

Using this combined treatment modality of radical surgical operation+IORT, improved survival rates were obtained for Stage II and III gastric cancer patients. However, the method was ineffective for more advanced, Stage IV, patients. The wider irradiation field method used for total gastrectomy patients was safe and no complications were encountered.

Refinement of the locus for X-linked recessive chondrodysplasia punctata

Although the locus for X-linked recessive chondrodysplasia punctata (CDPX1) has been mapped to the region between PABX and DXS31 (the critical region is about 3 Mb long), the precise location within the critical region has not been determined. In this paper, we describe a boy with a 46,Y,der(X)t(X;Y)(p22.3;q11)mat karyotype and review the genotype-phenotype correlations in three male patients with the combination of apparent lack of clinical features of CDPX1 and a partial deletion of the critical region. The results suggest that the region defined by the two BssHII sites at 3180 and 3570 kb from the Xp telomere may be the target region for the CDPX1 locus.

Heritable formation of neuroectodermal tumor in transgenic mice carrying the combined E1 region gene of adenovirus type 12 with the deregulated human renin promoter

Adenovirus early 1 (E1) region gene products, including E1A and E1B, are required for transcriptional regulation of viral and cellular promoters in infected and transfected culture cells and for transformation of primary rodent cells. Here, we established a line of transgenic mice carrying the E1 region gene of human adenovirus type 12 under the control of the human renin promoter, in which a neuroectodermal tumor derived from retroperitoneal, olfactory, and/or pelvic regions was heritably developed with varying degrees of incidence and the phenotype was successfully passed through six generations. The transgenes were located in the region E2-E3 bands of chromosome 7 with which no genetic linkage to neuroectodermal tumors was previously demonstrated, and expressed only in the tumors but not in another tissue examined. Notably, in addition to the expression of a neural marker gene N-CAM, the three nuclear oncogenes, c-, L-, and N-myc, were coexpressed in the tumors. These results suggest that E1A and E1B are cooperatively involved in the heritable formation of neuroectodermal tumors associated with co-expression of the three sets of myc family genes.

Calbindin-D 28k immunoreactivity in the cerebellum of spinocerebellar degeneration

We studied immunoreactivity for calbindin-D 28k (CaBP), an intracellular calcium-binding protein, in the cerebellum of control subjects and of patients with spinocerebellar degeneration (SCD) including sporadic olivopontocerebellar atrophy and familial cortical cerebellar atrophy. In the cerebellum, CaBP immunoreactivity was seen exclusively in the Purkinje cell in both SCD and control groups. However, the number of CaBP-immunoreactive Purkinje cells was significantly reduced in SCD. CaBP immunohistochemistry also disclosed abnormal morphological changes of Purkinje cells, which was not visualized on conventional strains or not clearly demonstrated on immunohistochemistry for neurofilaments. Moreover, reduced CaBP immunoreactivity was observed even in some remaining Purkinje cells of SCD suggesting that loss of CaBP precedes neuronal loss of Purkinje cell. We conclude that CaBP is a useful marker for Purkinje cell degeneration, and that reduced CaBP expression might have some association with the mechanism of the Purkinje cell degeneration in SCD.

Electron microscopic study on the regenerating epithelium of the chronic gastric ulcer

Specimens from 31 cases of human gastric ulcers and 3 ulcer scars obtained at surgery were studied by transmission and scanning electron microscopy. A layer of simple cuboidal epithelial cells arising at the margin of the gastric ulcer migrated toward the ulcer base. Two types of regenerating epithelium (RE) were found: gastric and intestinal cell types. The gastric cell type RE originated from the gastric epithelium and was composed of immature cells which later matured to form primitive gastric glands. The intestinal cell type RE migrated from the intestinal metaplasia bordering the ulcer and contained immature cells which developed into absorptive and goblet cells forming primitive crypts and villi. In both types of RE, the basal lamina was frequently lacking. Moreover, degeneration and necrosis were often seen, especially in severe inflammatory focus. Profiles of Helicobacter pylori were observed in the gastric lumen, on the gastric type RE in about one third of the cases, but they were never found on the intestinal type RE.

Three-dimensional configuration of crypts of different types of colorectal adenomas

The three-dimensional configuration of isolated crypts of normal human colonic mucosa and colorectal adenomas was examined by scanning electron microscopy. For isolation of the crypts, the digestion method with HC1 was used for formalin fixed tissues, and the separation method with ethylenediaminetetraacetic acid (EDTA) following ultrasonication was applied to fresh tissues. In a comparative study, the NaOH cell-maceration method, which visualized the sub-basal laminal collagen sheath, was applied. The isolated crypts from the normal colon were visualized as a single straight tubule resembling a test tube. Most isolated crypts of the tubular adenomas were visualized as elongated fan-like structures with several protuberances and a few short branchings. Their average length was more than twice that of the normal colonic mucosa crypts. Most crypts of the villous adenomas were visualized as slender tubules without protuberances and short branchings, and their average length was three times that of the tubular adenoma crypts. Most crypts of the tubulovillous adenomas were long and triangular with several longitudinal folds and protuberances, and the average length was about three times that of the tubular adenoma crypts.

Activation of the nuclear oncogenes N-myc and c-jun in carcinoid [correction of cartinoid] tumors of transgenic mice carrying the human adenovirus type 12 E1 region gene

The adenovirus (Ad) E1 region genes, E1A and E1B, are well known cooperatively to transform primary rodent cells and activate a number of cellular promoters, including nuclear oncogenes such as N-myc and c-jun, in transfected cell lines. However, there is still less information available on the in vivo mechanism(s) by which the E1 region gene, when chromosomally integrated in the living animals, exerts its effect on nuclear oncogene activation coupled with transformation. To investigate such in vivo activity of E1A we have used a series of microinjection experiments into fertilized eggs to generate three transgenic mice carrying the Ad12-type E1A/E1B genes under the control of the human renin gene. This transgene caused an early onset of bowel cartinoid tumors that express neural cell adhesion molecules, but do not metastasize to any region. Northern blot analysis revealed that the transgenes were considerably expressed in the tumors, but not in other tissues at detectable levels. Interestingly, the levels of N-myc and c-jun mRNAs in the cartinoid tumors were elevated 19- and 8-fold, respectively, as compared with those found in the control intestine. In contrast, the major histocompatibility complex (MHC) class I mRNA level was not altered between the tumor and control intestines, suggesting that this unchanged expression may reflect the loss of tumor metastasis. These findings provide the first in vivo evidence that the expression of the Ad12 E1 region gene induces cartinoid tumors associated with the activation of the nuclear oncogenes N-myc and c-jun.

Guanidine neurotoxins are released with the digestive fluid of crabs (Crustacea, Brachyura)

During agonistic interactions intertidal crabs, when exposed to air, produce a foam made of digestive secretions, sea water and air bubbles. They also may release their digestive secretions in water when disturbed. Crabs belonging to the families Majidae, Xanthidae and Portunidae from Atlantic and Pacific areas, not related with human poisoning, possess substances in their digestive secretion which are neurotoxic to mice, block action potentials in nerve preparations, and are reversible on washing. After purification in Bio-gel P-2 chromatography and HPLC analysis, the spontaneously regurgitated secretion, the digestive secretion collected by stomach cannulation of crabs, and the water aquarium replete of intertidal crabs kept overnight show the presence of guanidine neurotoxins.

Genetic complementation of the immortal phenotype in group D cell lines by introduction of chromosome 7

Human immortal cell lines have been classified into at least four (A-D) genetic complementation groups by cell-cell hybrid analysis, i.e., a hybrid derived from different groups becomes mortal. Recently we have demonstrated that introduction of human chromosome 7 suppresses indefinite division potential in the non-tumorigenic human immortalized fibroblast lines KMST-6 and SUSM-1, both assigned to complementation group D. By extending our microcell-mediated chromosome transfer, we found that chromosome 7 also suppresses division potential in the human hepatoma line HepG2 (again, assigned to group D). Chromosome 7 was thus shown to suppress indefinite growth in the above group D cell lines irrespective of their cell types, or whether they are tumorigenic or not. Since chromosome 7 had no such effect on representative cell lines derived from complementation group A, B or C, these results indicate that the senescence gene(s) commonly mutated in the group D cell lines is located on chromosome 7.

Corneal epithelium in keratoconus

Specular microscopy was employed to study the corneal epithelium of 20 keratoconus patients (17 male, 3 female, average age 23.9 +/- 6.6 years). The patients were divided into three groups based on the severity of the keratoconus; early, intermediate, and advanced. Initially, epithelial changes were limited to enlargement of the superficial cells. As the disease progressed, elongated cells became prominent. Irregularly configurated and nucleated epithelial cells were observed in all cases. Morphomeric analysis showed that the mean area of the corneal epithelial cells was 906 +/- 203 microns 2 in the early stage, 1,416 +/- 521 microns 2 in the intermediate stage, and 1,641 +/- 372 microns 2 in the advanced stage. The shape factor was 0.32 +/- 0.05, 0.76 +/- 0.22, and 0.81 +/- 0.17, respectively. Controls were chronic wearers of hard contact lenses without corneal pathology. Analysis of their epithelium revealed no abnormalities. This finding suggests that the epithelial changes observed in keratoconus are not due to the wearing of contact lenses, but rather to the disease itself.