Microsatellite instability in the mitochondrial DNA of colorectal carcinomas: evidence for mismatch repair systems in mitochondrial genome

The role, if any, that mitochondrial (mt) DNA alterations play in the carcinogenic process remains unclear. To determine whether mtDNA instability occurs in cancers, nine microsatellite sequences in the mtDNA were examined in 45 sporadic colorectal carcinomas. Alteration in a polycytidine (C)n tract within a non-coding displacement-loop (D-loop) region was detected in 20 carcinomas (44%), three of which also exhibited frameshift mutations in a polyadenosine (A)8 or polycytidine (C)6 tract within NADH dehydrogenase (ND) genes. Interestingly, all three mutant genes were predicted to encode truncated ND proteins, which lacked a large portion of the C-terminus. These results suggested that certain repair systems, like the mismatch repair systems in the nuclear genome, are required for mtDNA maintenance and that defects in these systems can lead to target mitochondrial gene mutations in colorectal carcinomas.

Microsatellite instability and mutation of mitochondrial and nuclear DNA in gastric carcinoma

BACKGROUND & AIMS

Microsatellite instability (MSI) in mitochondrial DNA (mtDNA) is observed in some colorectal carcinomas. We attempted to determine if mitochondrial MSI (mtMSI) and mutations occur in gastric carcinomas and if the mtMSI phenotype underlies specific clinicopathologic profiles.

METHODS

Sixty-two gastric carcinomas (34 intestinal and 28 diffuse types) were investigated. Coding mutations in 8 different mitochondrial genes, mtMSI in a noncoding (C)n tract, and p53 gene mutations were examined by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. MSI in nuclear DNA (nMSI) and loss of the p53 gene were examined using microsatellite markers.

RESULTS

Ten of 62 (16%) carcinomas showed the mtMSI phenotype. Mitochondrial gene mutation was detected in 5 carcinomas, 4 of which also showed the mtMSI phenotype. There was a positive correlation between mtMSI and nMSI status. In intestinal carcinomas, mtMSI, nMSI, and p53 gene alterations were frequently detected from early to advanced stages. In diffuse carcinomas, both kinds of MSI were found in only advanced (subserosal or serosal invasion) carcinomas. Six of 7 carcinomas with the nMSI phenotype and all 5 carcinomas with mitochondrial coding mutations had a considerable intestinal-type tumor cell component.

CONCLUSIONS

Mitochondrial gene mutations, which are associated with the mtMSI phenotype, may play a specific role in the tumorigenesis of intestinal-type gastric carcinomas.

Eosinophil cationic protein in peripheral blood of pediatric patients with allergic diseases

We have studied the levels of eosinophil cationic protein (ECP) and tumour necrosis factor (TNF) in peripheral blood obtained from 68 children with bronchial asthma and 11 children with atopic dermatitis. The ECP mean concentrations of the patients were 23.7 +/- 21.4 micrograms/l and 21.2 +/- 18.7 micrograms/l for bronchial asthma and atopic dermatitis respectively, which were significantly higher than the control value, 5.8 +/- 2.3 micrograms/l (P less than 0.005). TNF was unmeasurable in almost all the samples and no significant difference was observed between normal controls and asthmatic children. A significant correlation was observed between serum levels of ECP and blood eosinophil counts in both diseases (r = 0.873; P less than 0.01 and r = 0.740; P less than 0.01, respectively). However, no obvious correlation was observed between serum levels of ECP and IgE levels. ECP levels were significantly reduced by treatment and normalized in parallel with blood eosinophil counts in the patients with total IgE levels less than 800 U/ml. Irrespective of the total IgE levels, the reduction of serum ECP levels was correlated with a decrease in the number of asthmatic attacks and/or improvement of pulmonary function. These results suggest that the ECP levels in peripheral blood indicate an increased activity of eosinophil and would be a more useful marker than eosinophil counts for making clinical analyses and estimating treatment efficacy in paediatric patients with allergic diseases.

Mitochondrial gene mutation, but not large-scale deletion, is a feature of colorectal carcinomas with mitochondrial microsatellite instability

We have shown that microsatellite instability (MSI) occurs in mitochondrial DNA (mtDNA) of colorectal carcinomas. To determine whether such mitochondrial microsatellite instability (mtMSI) is associated with certain forms of mitochondrial gene alterations, we extended the screening in the same series of 45 carcinomas. Analysis by whole mtDNA amplification (16.5 kb) and digestion revealed no detectable large-scale change in these carcinomas. In contrast, single-strand conformation polymorphism (SSCP) analysis demonstrated NADH dehydrogense (ND) gene alterations in 7 carcinomas (16%), including 3 mononucleotide repeat alterations, 2 missense mutations and 1 small (15 bp) deletion. Six of these 7 carcinomas also exhibited mtMSI of the (C)n sequence in the displacement-loop (D-loop) region. Thus, frameshift or missense mutations rather than large-scale changes in the mtDNA were more common features in colorectal carcinomas with mtMSI. By analogy to mutational features of nuclear MSI, mtMSI most likely results from certain repair deficiencies in the mtDNA and probably plays a role in the tumor development of certain colorectal carcinomas.

Growth activity in hyperplastic and neoplastic human thyroid determined by an immunohistochemical staining procedure using monoclonal antibody MIB-1

To increase our understanding of the basic biological mechanisms of thyroid diseases, growth activity (GA) in 232 thyroid lesions was determined by immunohistochemistry using monoclonal antibody MIB-1. The GA tended to be higher in hyperplastic lesions, adenomatous goiter (MIB-1-positive cell rate, 0.73%), and Graves' disease (1.68%) than in normal tissue (0.19%). The GA for differentiated thyroid carcinomas (2.00%) was much lower than for adenocarcinomas of other organs, such as breast, lung, stomach and colon (44.67%). Of the thyroid carcinomas, the highest GA was observed in undifferentiated carcinomas (32.67%), and follicular carcinomas (3.18%) showed a higher GA than papillary carcinomas (1.83%). There was no significant difference between the GA of follicular carcinomas and solid/trabecular adenomas, although widely invasive follicular carcinomas showed a higher GA than minimally invasive carcinomas. No significant correlations between GA and patient age, sex, and tumor diameter, metastasis, or histological features were observed in papillary carcinomas. Familial medullary carcinomas showed a higher GA than sporadic tumors. All latent papillary carcinomas had a very low GA. Our findings suggest that immunohistochemical investigation using the antibody MIB-1 contributes to the understanding of growth characteristics and biological activities in thyroid diseases.

Clinical study on prognostic factors for autotransplantation of teeth with complete root formation

Autotransplantation is often performed to replace a missing tooth, but tooth autotransplantation has been reported in fewer teeth with complete root formation than those with incomplete root formation. The aim of this prospective study was to evaluate the factors that affect the prognosis of autotransplantation of teeth with complete root formation. 109 patients with 117 transplants were studied. Of the 117 transplants investigated, 14 (12%) failed during the observation period. The overall 1-year survival rate was 96%; the 5-year survival rate was 84%. The major causes of failure were unsuccessful initial healing and replacement root resorption with periodontal inflammation. Factors significantly associated with unsuccessful transplantation, in single factor analysis, were age 40 years or more, molar tooth as donor, probing pocket depth to 4mm or more, history of root canal treatment, multi-rooted teeth and fixation with sutures. Pocket depth of 4mm or more and history of root canal treatment appeared to increase the risk of unsuccessful transplantation in multivariate analysis. It is suggested that the pocket depth of the donor tooth and history of root canal treatment are related to the healing of paratransplantal tissue and root resorption.

Nasal defects and osseointegrated implants: UCLA experience

A clinical study of 23 craniofacial implants placed in 11 nasal defects was conducted over a 7-year period. Implant-retained nasal prostheses were fabricated, implant success rate was determined, and the soft tissue responses were recorded at 6-month intervals. No data were gathered on two implants because of patient death. The implant success rate was 71.4% (15/21) but varied significantly by anatomic site. The implant success rate in the glabella was 0% (0/4), whereas the success rate in the anterior nasal floor was 88.1% (15/17). All implant failures occurred within the first year of loading. A five-point scale was used to record the health of the peri-implant soft tissues, and the patients were followed up from 6 to 74 months. The unit of measure was a visit/site, and a unit was assigned for each instance an implant site was evaluated. Evaluations were conducted at 6-month intervals for a total of 76 visit/sites for the study period. The results revealed that 85.5% (65/76) of the visit/sites demonstrated an absence of inflammation; 10.5% (8/76) of the visit/sites demonstrated slight redness; 1.3% (1/76) demonstrated peri-implant red and moist tissues; 2.6% (2/76) demonstrated granulation tissue associated with the implants; and 0% (0/76) demonstrated infection of the peri-implant soft tissues. Severe soft tissue reactions around implants placed in the anterior nasal floor are rare.

The effect of 5-hydroxytryptamine 3A and 3B receptor genes on nausea induced by paroxetine

We investigated the effect of 5-hydroxytryptamine 3A and 3B receptor (HTR3A and HTR3B) gene polymorphisms on nausea induced by paroxetine in Japanese psychiatric patients. Blood samples were collected from 78 individuals after at least 2 weeks treatment with the same daily dose of paroxetine. The patients visited every 2 weeks and the paroxetine dose was changed in response to their clinical symptoms. Nausea was assessed at each visit. The Tyr129Ser polymorphism of the HTR3B gene had a significant effect on the incidence of nausea (P=0.038). Logistic regression analysis also showed that patients with the Tyr/Tyr genotype had a 3.95-fold (P=0.048) higher risk of developing nausea than patients with the Ser allele. HTR3A gene polymorphisms and the CYP2D6 gene polymorphisms had no significant effect on the incidence of nausea. The mean score of nausea severity was corrected by the Bonferroni test. HTR3B gene polymorphisms are significant predictors of paroxetine-induced nausea.

Blood purification for prevention and treatment of multiple organ failure

Blood purification has been applied conventionally as an artificial kidney or artificial liver in the management of patients with multiple organ failure (MOF), and most blood purifications have been performed intermittently. Recent advances in medical engineering made it possible to perform such blood purifications continuously (i. e., 24 hours a day, 7 days a week if necessary) even in critically ill patients. This modality is referred to as continuous renal replacement therapy (CRRT) or continuous blood purification (CBP). Among many kinds of CBP, continuous hemodiafiltration (CHDF) is most useful for management of MOF, as it can be performed without serious or hazardous side effects, and improvement can be expected with it. Recently, CHDF and polymyxin B immobilized endotoxin adsorption columns were used for the prevention or treatment of MOF, with the expectation that such therapy can be effective as a countermeasure against the pathophysiologic causes of MOF. Our data and that of others clearly indicate that continuous blood purification, such as with CHDF and endotoxin adsorption, can remove or decrease the blood levels of humoral mediators, including proinflammatory cytokines, and can improve tissue oxygenation, especially oxygen consumption (VO2) among critically ill patients including those with MOF. Blood purification is also useful in the careful management of fluid, electrolytes, and acid-base balance and for the removal of metabolic wastes. Blood purification is now considered to be one of the basic therapeutic tools of critical care, equal to nutritional support with total parenteral nutrition and respiratory support without a ventilator.

Osseointegrated implants and orbital defects: U.C.L.A. experience

PURPOSE

A clinical study of 23 craniofacial implants placed in 8 irradiated and nonirradiated orbital detects was conducted over a 7-year period.

MATERIAL AND METHODS

Implant-retained orbital prostheses were fabricated, implant success rate was determined, and the soft tissue responses were recorded at 6-month intervals. As a result of patient death, no data were gathered on three implants. A five-point scale was used to record the health of the peri-implant soft tissues and the patients were followed from 9 to 72 months. The unit of measure was a visit/site that was assigned for each instance an implant site was evaluated. Evaluations were conducted at 6-month intervals, and for the study period, there were 80 visit/sites.

RESULTS

The study revealed that 42.5% (34/80) of the visit/sites demonstrated an absence of inflammation; 23.7% (19/80) of visit/sites demonstrated slight redness; 13.8% (11/80) demonstrated peri-implant red and moist tissues; 6.2% (5/80) demonstrated granulation tissue associated with the implants; and 13.8% (11/80) infection of the peri-implant soft tissues was noted. Implant success rate was 35% (7/20); implant success rate in the nonradiated patients was 37.5% (3/8) and the success rate for radiated patients was 33.3% (4/12). Implants placed in the orbital region demonstrated a high failure rate. Most implant failures occurred late as opposed to early in the study period.

CONCLUSION

Orbital implants should be placed in patients who understand that long-term success rates may be low and require meticulous hygiene maintenance.

Auricular prostheses and osseointegrated implants: UCLA experience

A clinical study of 40 craniofacial implants placed in 13 auricular defects was conducted over a 6-year period. Implant-retained prostheses were fabricated, the implant success rate was determined, and the soft tissue responses were recorded at regular intervals. All of the implants became osseointegrated and none demonstrated failure during the study period. A five-point scale was used to record the health of the peri-implant soft tissues and the patients were followed up for up to 69 months. The results were as follows: 55.1% of the visit/sites demonstrated an absence of inflammation; 32.3% of the visit/sites demonstrated slight redness; 4.7% demonstrated red and moist peri-implant tissues; 5.5% demonstrated granulation tissue associated with the implants; and in 2.4% of the implants, infection of the peri-implant soft tissues was noted. Good patient hygiene compliance combined with thin and immobile peri-implant soft tissues resulted in minimal soft tissue complications.

Subdivisions of the guinea-pig accessory olfactory bulb revealed by the combined method with immunohistochemistry, electrophysiological, and optical recordings

The presence of subgroups in vomeronasal sensory neurons has been known in various animals. To elucidate possible functional subdivisions in the guinea-pig accessory olfactory bulb, the combined studies with GTP-binding protein immunohistochemistry, electrophysiological and optical recordings were carried out. Gi2 alpha and Go alpha proteins were immunohistochemically localized, respectively, in the anterior and posterior regions of the vomeronasal nerve and glomerular layers, indicating that the guinea-pig accessory olfactory bulb receives at least two different inputs. This suggests that an anatomical boundary exists in these two layers. A mapping study of field potentials in sagittal slice preparations demonstrated that stimulation of the anterior vomeronasal nerve layer elicited field potentials with weak oscillatory responses exclusively in the anterior region of the external plexiform layer, whereas shocks to the posterior vomeronasal nerve layer provoked distinct oscillatory responses within the posterior one. The damping factors of oscillations in the anterior and posterior regions were 0.064+/-0.028 and 0.025+/-0.014, respectively. These electrophysiological results suggest that the accessory olfactory bulb consists of two functionally different subdivisions. Real-time optical imaging showed that anterior vomeronasal nerve layer shocks produced neural activity which spread horizontally from anterior to posterior only within the anterior region of the external plexiform and mitral cell layers, whereas shocks to the posterior vomeronasal nerve layer evoked periodic neural activity which spread horizontally from posterior to anterior only within the posterior region. Furthermore, the most posterior extent of the optical response evoked in the anterior region immediately adjoined the most anterior extent of that evoked in the posterior region. The maximal distance of signal propagation in the granule cell layer corresponded to that in the overlying external plexiform and mitral cell layers, indicating that the granule cell layer also has a similar boundary. Thus, these optical imaging studies not only demonstrated a precise boundary in each layer of the accessory olfactory bulb, which was positioned right beneath the boundary defined by GTP-binding protein immunohistochemistry, but also confirmed the observations from electrophysiological mapping that evoked field potentials are independently distributed in each of two subdivisions. The presence of the functional subdivision in each layer leads us to conclude that the accessory olfactory bulb in the guinea-pig is distinctly segregated into the anterior and posterior subdivisions, and to suggest that there are at least two different input output pathways in the vomeronasal system.

Selective suppression of horizontal propagation in rat visual cortex by norepinephrine

The release of norepinephrine in the cerebral cortex from axon terminals of locus coeruleus neurons was suggested to be involved in the control of attention. Accumulating data indicate that the responses of cortical neurons are varied when norepinephrine is applied iontophoretically in the vicinity of the cells being recorded. However, it is not known how the pattern of excitatory propagation is modified when norepinephrine is applied over a wide area in the visual cortex. By applying optical imaging to rat visuocortical slices, we found a new mode of norepinephrine action; a prominent suppression of the horizontal propagation in layers II/III. This action of norepinephrine was confirmed by the simultaneous recording of field potentials from multiple sites by use of a multi-electrode dish. Furthermore, our electrophysiological recordings showed that this norepinephrine action is exerted through suppression of excitatory neural transmission and enhancement of inhibitory transmission to the pyramidal neurons in these layers. Because the release of norepinephrine in the visual cortex is regulated by the level of attention, the neural basis of visual attention may relate partially to the suppression of the integration of visual information by norepinephrine resulting in a state-dependent restructuring of the receptive field.

Actions of cholinergic agonists and antagonists on the efferent synapse in the frog sacculus

Intracellular recordings were made from hair cells in the frog saccular epithelium isolated with its innervating nerves. Inhibitory post-synaptic potentials (IPSPs) were recorded from hair cells when the efferent fibers were activated by electrical stimulation. The effects of acetylcholine (ACh), cholinomimetics, and cholinergic antagonists on the efferent synapse were studied in a preparation where the IPSPs can be observed directly. ACh or carbachol (CCh) produced a transient membrane hyperpolarization with a decrease in input resistance followed by an abolition or reduction of the IPSP. In a low Ca2+ medium where efferent synaptic activity was abolished, ACh or CCh still induced hyperpolarization, though the response appeared to be smaller than that in normal medium. Neither nicotinic (dimethyl-4-phenyl-piperazinium (DMPP), phenyltrimethylammonium (PTMA) and nicotine) nor muscarinic (muscarine, methacholine, bethanechol and oxotremorine) agonists induced the membrane hyperpolarization, but the former drugs inhibited the IPSPs while the latter drugs did not. Both d-tubocurarine and atropine inhibited the IPSP, but the d-tubocurarine was more potent, causing inhibition even at a dose of 0.5 microM while 2 microM or more atropine was needed. The ACh- or CCh-induced hyperpolarization was inhibited completely by d-tubocurarine (5 microM), but only slightly by atropine (5 microM). These results may indicate that the IPSP and the effects of ACh or CCh are based on a direct interaction between ACh or CCh and ACh receptors on the hair cells.

Adult-onset leukoencephalopathy with vanishing white matter with a missense mutation inEIF2B5

We report of a woman aged 52 years born to consanguineous parents and seeking treatment for progressive dementia and delusion. Neurologic examination revealed dementia and emotional instability, indifference, and confabulation. There was also mild spasticity of the bilateral lower limbs. MRI revealed diffuse white matter hyperintensity on T2-weighted images accompanied by hypointense areas on fluid-attenuated inversion recovery images. A homozygous missense mutation was identified in EIF2B5.

Comparison of Sepsis-related Organ Failure Assessment (SOFA) score and CIS (cellular injury score) for scoring of severity for patients with multiple organ dysfunction syndrome (MODS)

OBJECTIVE

To evaluate the usefulness of cellular injury score (CIS) and Sepsis-related Organ Failure Assessment (SOFA) score for determination of the severity of multiple organ dysfunction syndrome (MODS).

DESIGN

A prospective observational study.

SETTING

A medical and surgical intensive care unit (ICU) of a teaching hospital.

PATIENTS

Forty-seven consecutive MODS patients.

MEASUREMENTS AND RESULTS

SOFA score and CIS were measured every day for 12 months for 47 MODS patients. Comparison was made of the SOFA score and CIS for usefulness in the scoring of severity of MODS in 26 survivors and 21 non-survivors. In addition, receiver operating characteristics (ROC) analysis was used to determine the usefulness of these two indexes as predictors of prognosis. No significant differences were found on admission between the survivors and non-survivors, but significant differences between the two subgroups (p < 0.001) were found in maximum value within 1 week after admission and maximum value during the course of treatment for both indexes. Analysis of changes after admission indicated that significant differences between survivors and non-survivors began to appear on day 3 of admission for both indexes; at that time SOFA score began to deteriorate in the non-survivors while CIS began to improve in the survivors. ROC analysis demonstrated that the area under the ROC curve was 0.769 for SOFA scores and 0.760 for CIS.

CONCLUSIONS

Both SOFA score and CIS sequentially reflected the severity of MODS. Furthermore, they were comparable in diagnostic value as predictors of prognosis. These findings may indicate the possibility that MODS is a summation of effects of cellular injury. In addition, sequential evaluation of both SOFA score and CIS would provide a more accurate prediction of prognosis than conventional methods.

Access to Wieland-Miescher ketone in an enantiomerically pure form by a kinetic resolution with yeast-mediated reduction

Both enantiomers of Wieland-Miescher ketone [3,4,8, 8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione], in a highly enantiomerically enriched form, became readily available by a newly developed kinetic resolution with yeast-mediated reduction. From a screening of yeast strains, Torulaspora delbrueckii IFO 10921 was selected. The collected cells of this strain, obtained by an incubation in a glucose medium, smoothly reduced only the isolated carbonyl group of the (S)-enantiomer, while the (R)-enantiomer remained intact. Starting from both enantiomers ( approximately 70% ee) prepared by an established proline-mediated asymmetric Robinson annulation, the reduction with T. delbrueckii gave the (R)-enantiomer (98% ee) and the corresponding alcohol (4aS,5S)-4,4a, 5,6,7,8-hexahydro-5-hydroxy-4a-methyl-2(3H)-naphthalenone (94% ee, 94% de) in preparative scale in nearly quantitative yields. An approach for the asymmetric synthesis of the Wieland-Miescher ketone was also successful. 2-Methyl-2-(3-oxobutyl)-1,3-cyclohexanedione, the prochiral precursor, was reduced with this strain to give a cyclic acetal form of (2S, 3S)-3-hydroxy-2-methyl-2-(3-oxobutyl)cyclohexanone, in a stereomerically pure form.

The role of inositol trisphosphate on ACh-induced outward currents in bullfrog saccular hair cells

Acetylcholine (ACh) is considered as the most likely candidate for a neurotransmitter of the efferent synapse onto hair cell. In this paper, the nature of this cholinergic receptor mechanism on dissociated bullfrog saccular hair cell was examined by using whole cell recording and Ca2+ sensitive fluorophotometric technique. Both the ACh-induced current and the increase of [Ca2+]i were observed in an oscillatory manner, and were the largest around the basal part of the cell where the efferent synapse is thought to make a contact with the membrane. The reversal potential of ACh-induced current indicated that ACh activated a K+ conductance. The ACh-induced current was reversibly blocked by atropine, d-tubocurarine (dTC), apamin, tetraethylammonium (TEA) and quinine. Neither muscarine nor nicotine mimicked the ACh-induced current. When GTP gamma S was injected into a hair cell, the first ACh application induced an outward current of transient kinetics, but in subsequent trials ACh-induced current lost its decay phase. Intracellularly injected D-myo-inositol 1,4,5-trisphosphate (InsP3) generated outward currents. Intracellularly injected heparin suppressed ACh-induced currents, and lithium (Li+) increased ACh-induced currents. These results indicate that ACh activates a receptor coupled with a guanine nucleotide binding protein (G-protein) which triggers metabolic cascades of InsP3 and Ca2+ leading to the activation of the Ca(2+)-activated K+ channel.

Microsatellite instability in gallbladder carcinoma: two independent genetic pathways of gallbladder carcinogenesis

Although the genetic basis for gallbladder carcinogenesis has not been clarified, considerable evidence has shown that genetic alterations play an important role in the development and progression of human cancers. In this study, we analyzed 30 gallbladder carcinomas to investigate the role of genetic alterations in their tumorigenesis, and to study correlations with their clinicopathological features. Tissue samples were obtained from 30 patients with gallbladder carcinoma (11 men and 19 women; mean age, 62 years; age range, 38-80 years). Genomic DNAs were extracted from fresh tumor tissue. We examined loss of heterozygosity (LOH) in the p53, APC, DCC, RB, and NM23-H1 gene regions by polymerase chain reaction (PCR)-LOH assay using an automated fluorescent DNA sequencer employing four microsatellite markers (p53, APC, DCC, NM23-H1). Five additional microsatellite markers were used for the determination of microsatellite instability (MSI). LOH was found at p53 in 9 of 15 informative cases (60%), at DCC in 10 of 22 (45%), at APC in 5 of 15 (33%), at RB in 1 of 8 (13%), and at NM23-H1 in 1 of 15 (7%). MSI was observed in 5 of 30 cases (17%) in at least one chromosomal loci of these nine microsatellite markers. None of the patients with MSI-positive tumors showed lymph node metastasis, and there was an inverse correlation between MSI and the presence of LOH in gallbladder carcinoma. These results suggest that there are two independent genetic pathways in gallbladder carcinogenesis; that is, an MSI pathway and an LOH pathway.

Cell proliferation and p53 protein expressions in cutaneous epithelial neoplasms

We investigated correlations between cell proliferation, p53 overexpression, and degree of malignancy in cutaneous epithelial neoplasms. One hundred and fourteen cases of epithelial neoplasms, including seborrheic keratosis (SEB), basal cell carcinomas (BCCs), solar keratosis (SK), Bowen's disease (BD), and squamous cell carcinomas (SCCs) were examined using argyrophilic nucleolar organizer region (AgNOR) staining. In addition, immunohistochemical analysis using the Ki-67 (MIB-1) and anti-p53 (DO-7) monoclonal antibodies was performed. The ratio of tumorous to normal cells according to AgNOR staining was defined as the AgNOR rate, and the ratio of tumorous to normal cells according to Ki-67 recognition was defined as the Ki-67 rate. SCC lesions showed the highest AgNOR rate among the investigated epithelial neoplasms, followed in order by BD, BCC, SK, and SEB lesions. The Ki-67 rate was highest in BD lesions, followed in order by SK, SCC, BCC, and SEB lesions. Expression of p53 protein was highest in SK lesions. SCC is generally considered to be the most malignant neoplasm, followed in order by BCC, BD, and SK. Thus, our results suggest that the Ki-67 rate and overexpression of p53 protein do not always reflect the degree of malignancy in neoplasms.

Effects of activation of the divergent efferent fibers on the spontaneous activity of vestibular afferent fibers in the toad

In anesthetized toads, spontaneous activities were recorded from single afferent fibers of three semicircular canals and three otolith organs. Since some efferent fibers ramify within the eighth nerve and innervate two or more vestibular organs, a single branchlet of the eighth nerve was disconnected from its end organ, and was electrically stimulated to activate divergent efferent collaterals leading to other vestibular organs. The stimulation elicited an inhibitory effect on spontaneous activities of about one third of the afferent population, and a facilitatory effect on those of another one third. The remaining one third was unaffected. Whether or not the inhibitory or facilitatory effect was observed in an individual unit seemed to be related to its pattern and its rate of spontaneous activity. Most of the units showing relatively high and regular spontaneous firing were insensitive to the electrical stimulation, and units with a low firing rate and an irregular pattern of activity tended to be affected by the electrical stimulation. The activation of divergent efferent fibers elicited both inhibition and facilitation on the spontaneous afferent activities in all vestibular nerve branchlets, except in the saccular branchlet, where only inhibition was elicited. Electrical stimulation of the central stump of the saccular nerve branchlet, however, could produce both inhibitory and facilitatory effects in other vestibular nerve branchlets.

Odor-concentration coding in the guinea-pig piriform cortex

By optical imaging of intrinsic signals, we demonstrated a possible code for odor concentration in the anterior piriform cortex of the guinea-pig. Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex. Lower concentrations activated the rostral region of the band, whereas higher ones generated caudally spreading activation, and the site at which neural activation reached its maximum extent depended upon odor concentration. Different odors with low concentrations generated distinct but somewhat overlapping patterns in the rostral region of the band; the limited extent of cortical activity may be one focal domain for each odor. It was hard to judge, however, that odor-specific domains appeared in the anterior piriform cortex, because the strong stimuli induced largely overlapping patterns. Furthermore, the total area activated increased in proportion to concentrations raised to a power of 0.5-0.9. Importantly, these imaging results were confirmed with unit recordings which indicated a rostro-caudal gradient in odor-sensitivity among cortical neurons. Our results suggest that the dorsal part of the anterior piriform cortex may be associated with odor concentration. Therefore, in addition to recruitment of more olfactory sensory cells and glomeruli in response to stronger stimuli, a rostro-caudal gradient in axonal projections from mitral/tufted cells and/or in association fibers may play an important role in odor-concentration coding in the anterior piriform cortex.