Penetrating colon ulcer of polyarteritis nodosa: report of a case

A 54-year-old Japanese female with polyarteritis nodosa was admitted to the hospital. She developed lower abdominal pain accompanied by melena. A penetrating ulcer and extensive hemorrhaging were endoscopically observed in the sigmoid colon, and a sigmoidectomy was performed. The pathologic findings were a granuloma formation with lymphocytic infiltration and luminal occlusion of branches of the mesenteric arteries. Although the gastrointestinal tract is frequently involved in polyarteritis nodosa, the colon is rarely affected. To our knowledge, this is the first report of polyarteritis nodosa causing a penetrating ulcer of the colon.

Progesterone inhibits apolipoprotein-mediated cellular lipid release: a putative mechanism for the decrease of high-density lipoprotein

In order to investigate the mechanism for female gonadal hormones to regulate the plasma high-density lipoprotein (HDL) level, the effect of 17 beta-estradiol and progestogens was examined in vitro on the assembly of HDL by free apolipoprotein A-I (apoA-I) with cellular cholesterol and phospholipid. ApoA-I generated HDL particles by removing cholesterol and phospholipid from human fibroblasts, MRC-5. While 17 beta-estradiol did not influence this reaction, progesterone suppressed the removal by apoA-I of both cholesterol and phospholipid, with the extent of the inhibition more for cholesterol than phospholipid. Three other synthetic progestogens showed the similar inhibitory effect on the cellular cholesterol release. Cellular cholesterol de novo-synthesized from mevalonolactone entered more into the acyl-esterified cholesterol compartment and less to the unesterified compartment in the presence of progesterone. On the other hand, progesterone did not influence the overall mass ratio of free and esterified cholesterol in the cell. Cell-surface cholesterol was also uninfluenced by progesterone when probed by extracellular cholesterol oxidase reaction or by diffusion-mediated cellular cholesterol release to cyclodextrin. Neither caveolin-1 nor ABCA1 expression was influenced by progesterone. Progesterone thus seems primarily to alter the specific intracellular cholesterol compartment that is related to the apoA-I-mediated HDL assembly. This mechanism might contribute to the decrease of plasma HDL by administration of progestogen in women under hormone replacement therapy.

Mixed duct-acinar-islet cell tumor of the pancreas: report of a case

A 72-year-old Japanese woman presented at our hospital complaining of altered consciousness on arising every morning. The laboratory findings showed hypoglycemia and hyperinsulinemia. Abdominal ultrasonography revealed a tumor in the body of the pancreas. With a diagnosis of insulinoma, a surgical excision of the tumor was performed. A light microscopic examination and an immunohistochemical study revealed the tumor to consist of duct, acinar, and islet cell components. Mixed tumors of the pancreas are rare, and their clinical features and pathogenesis remain unclear. A further accumulation of clinical cases as well as a large number of histopathological studies on these rare mixed tumors is needed.

[A case of drug-resistant pulmonary tuberculosis treated successfully following disappearance of rifampicin resistance after 17 years' chemotherapy]

A female who first acquired pulmonary tuberculosis in 1962 when she was 25 years old, admitted to the National Hiroshima Hospital in 1982. Her sputum has been smear positive for acid-fast bacilli for 3 years before admission in spite of continuous antituberculous chemotherapy, and were resistant to isoniazid (INH) and rifampicin (RFP). She was treated with a regimen containing ethambutol (EB), prothionamide (TH) and enviomycin (EVM) but continued to be culture positive. Though she was treated with various regimens which include one to three sensitive drugs, her sputum continued to be positive for M. tuberculosis in the following 14 years. During the course, resistance to EB, TH, cycloserine (CS) and streptomycin (SM) emerged. Resistance to RFP temporarily retracted in 1988, but her sputum was bacilli negative only for 2 months after the addition of RFP to previous regimen, and followed by resurgence of RFP resistance. In 1992, data of drug sensitivity tests showed sensitivity to TH, CS and RFP in turn, which were not used for 3 to 5 years. In 1993, she was treated with RFP, TH and EVM successfully and continued to be bacteriologically negative for 7 years so far. Drug resistance to M. tuberculosis is induced by inappropriate chemotherapy as seen in this case. Regimens with less than three drugs without RFP and INH was not only insufficient to get cure but, what was worse, also induced additional resistance to used drugs. The reason of successful chemotherapy in this case was spontaneous disappearance of drug resistance to RFP and TH. This case suggests that the disappearance of drug resistance is possible, when drugs are not used for more than a few years, hence the successful treatment could be expected. However it must be emphasized that the drug resistance is produced by incorrect treatment as seen in this case, and its prevention is of the prime importance.

Temporal facilitation for moving stimuli is independent of changes in direction

A flash that is presented aligned with a moving stimulus appears to lag behind the position of the moving stimulus. This flash-lag phenomenon reflects a processing advantage for moving stimuli (Metzger, W. (1932) Psychologische Forschung 16, 176-200; MacKay, D. M. (1958) Nature 181, 507-508; Nijhawan, R. (1994) Nature 370, 256-257; Purushothaman, G., Patel, S.S., Bedell, H.E., & Ogmen, H. (1998) Nature 396, 424; Whitney, D. & Murakami, I. (1998) Nature Neuroscience 1, 656-657). The present study measures the sensitivity of the illusion to unpredictable changes in the direction of motion. A moving stimulus translated upwards and then made a 90 degrees turn leftward or rightward. The flash-lag illusion was measured and it was found that, although the change in direction was unpredictable, the flash was still perceived to lag behind the moving stimulus at all points along the trajectory, a finding that is at odds with the extrapolation hypothesis (Nijhawan, R. (1994) Nature 370, 256-257). The results suggest that there is a shorter latency of the neural response to motion even during unpredictable changes in direction. The latency facilitation therefore appears to be omnidirectional rather than specific to a predictable path of motion (Grzywacz, N. M. & Amthor, F. R. (1993) Journal of Neurophysiology 69, 2188-2199).

Visual jitter: evidence for visual-motion-based compensation of retinal slip due to small eye movements

When dynamic random noise is replaced by static noise after a period of adaptation, adjacent unadapted regions filled with static noise appear to 'jitter' coherently in random directions for several seconds, actually mirroring the observer's own eye movements of fixation [Murakami, I. & Cavanagh, P. (1998). Nature, 395, 798-801]. The present study aims at psychophysically locating two distinct stages underlying this visual jitter phenomenon: a monocular, adaptable stage that measures local retinal motion and a compensation stage that estimates a baseline motion minimum and subtracts it from motion vectors nearby. The first three experiments revealed that visual jitter has storage, directional selectivity, and spatial frequency selectivity, like the motion after-effect does. These results suggest some overlap in the adaptation mechanisms for the two effects, possibly at or below the level of primary visual cortex. The next two experiments revealed the transfer of the effect across the vertical meridian as well as the existence of a preferred stimulus size that is a linear increasing function of eccentricity, mimicking the RF size of the monkey MT neurons. These results suggest that some extrastriate motion area along the parietal pathway including MT mediates motion-based compensation of retinal slip.

A case of massive subchorionic thrombohematoma diagnosed by ultrasonography and magnetic resonance imaging

Massive subchorionic thrombohematoma is uncommon but associated with a poor perinatal prognosis. Placental enlargement was detected in a 25-year-old Japanese primipara woman with fetal growth retardation and oligohydramnios at 23 weeks' gestation. Ultrasonography (USG) showed an abnormal sonolucency within the placenta at 28 weeks' gestation, but could not give an unequivocal differentiation from placental abnormalities such as hematomas, cysts and other tumors. Magnetic resonance imaging (MRI) pointed to a large hematoma in the subchorionic region. Simultaneously, the amniotic fluid was brownish colored. From these findings, it was possible to have prenatal diagnosis of massive subchorionic thrombohematoma. At 32 weeks' gestation, the fetus died in utero and was stillborn 3 days later. Pathological findings for the placenta revealed a large hematoma diffused between the villous chorion and the chorionic plate, with wide necrosis of placental tissue, likely due to formation of multiple thrombi. The clinical and pathological findings were compatible with massive subchorionic thrombohematoma. MRI might be useful for the detection of massive subchorionic thrombohematoma and help its clinical management in combination with USG and pulse Doppler imaging.

Neural responses in the retinotopic representation of the blind spot in the macaque V1 to stimuli for perceptual filling-in

When visual stimuli that cover the entire blind spot are presented monocularly, the color and brightness of the surrounding field are seen within the blind spot, although it receives no retinal input. Important questions about such perceptual filling-in are whether neurons in the visual system representing visual field locations within the blind spot are activated when filling-in occurs and, if so, what the properties of these neurons are. To address these questions, we recorded the activities of single neurons in the primary visual cortex (V1) of the awake monkey. We first identified the area of V1 representing the region of the blind spot and then assessed neural responses to stationary visual stimuli of various size. We found that there are neurons in layer 4 and deeper laminae, particularly layer 6, that respond to large stimuli covering the blind spot which induces perceptual filling-in. Most of these neurons had very large binocular receptive fields that extended outside the blind spot. These neurons also preferred relatively large stimuli and exhibited color selectivity. These results indicate that when a large uniform surface is presented on the blind spot, neurons at the V1 region representing the blind spot transmit signals essential for filling-in that inform of the presence of a large surface as well as the absence of smaller stimuli at the blind spot.

Illusory spatial offset of a flash relative to a moving stimulus is caused by differential latencies for moving and flashed stimuli

A flash that is presented adjacent to a continuously moving bar is perceived to lag behind the bar. One explanation for this phenomenon is that there is a difference in the persistence of the flash and the bar. Another explanation is that the visual system compensates for the neural delays of processing visual motion information, such as the moving bar, by spatially extrapolating the bar's perceived location forward in space along its expected trajectory. Two experiments demonstrate that neither of these models is tenable. The first experiment masked the flash one video frame after its presentation. The flash was still perceived to lag behind the bar, suggesting that a difference in the persistence of the flash and bar, does not cause the apparent offset. The second experiment employed unpredictable changes in the velocity of the bar including an abrupt reversal, disappearance, acceleration, and deceleration. If the extrapolation model held, the bar would continue to be extrapolated in accordance with its initial velocity until the moment of an abrupt velocity change. The results were inconsistent with this prediction, suggesting that there is little or no spatial compensation for the neural delays of processing moving objects. The results support a new model of temporal facilitation for moving objects whereby the apparent flash lag is due to a latency advantage for moving over flashed stimuli.

Detection of skin over cysts with Spina bifida may be useful not only for preventing neurological damage during labor but also for predicting fetal prognosis

Spina bifida is one of the most common open neural tube defects. There are two common types of spina bifida cystica, myelomeningocele and meningocele. Special attention to the thickness of the cystic sac (presence of intact skin and subcutaneous tissue) on magnetic resonance imaging is advantageous for determination of whether the child will profit from cesarean section in order to prevent neurological change (infection and drying of nerve tissue) and for management of spina bifida (most meningocele) during the perinatal period. Furthermore, skin detection may help to predict the prognosis of spina bifida after birth. Meningocele, with intact skin over the cyst, has a better clinical course than myelomeningocele. Some myelomeningoceles with neural tube defects in a lower position, also frequently having an intact skin over the cyst, have almost the same clinical course as a meningocele. From this, we hypothesize that a baby with spina bifida who has intact skin over the cyst might have a good prognosis neurologically. In this report, we concentrate attention on the skin over cysts in 3 cases (1 meningocele and 2 myelomeningoceles).

Neural selectivity for hue and saturation of colour in the primary visual cortex of the monkey

In the inferior temporal (IT) cortex of monkeys, which has been shown to play a critical role in colour discrimination, there are neurons sensitive to a narrow range of hues and saturation. By contrast, neurons in the retina and the parvocellular layer of the lateral geniculate nucleus (pLGN) encode colours in a way that does not provide explicit representation of hue or saturation, and the process by which hue- and saturation-selectivity is elaborated remains unknown. We therefore tested the colour-selectivity of neurons in the primary visual cortex (V1) and compared it with those of pLGN and IT neurons. Quantitative analysis was performed using a standard set of colours, systematically distributed within the CIE (Commission Internationale de l'Eclairage)-xy chromaticity diagram. Selectivity for hue and saturation was characterized by analysing response contours reflecting the overall distribution of responses across the chromaticity diagram. We found that the response contours of almost all pLGN neurons were linear and broadly tuned for hue. Many V1 neurons behaved similarly; nonetheless, a considerable number of V1 neurons had clearly curved response contours and were selective for a narrow range of hues or saturation. The relative frequencies of neurons exhibiting various selectivities for hue and saturation were remarkably similar in the V1 and IT cortex, but were clearly different in the pLGN. Thus, V1 apparently plays a very important role in the conversion of colour signals necessary for generating the elaborate colour selectivity observed in the IT cortex.

Sex chromosomal analysis of spermatozoa from infertile men using fluorescence in situ hybridization

PURPOSE

To confirm an association between male infertility and chromosome aberrations of spermatozoa, we demonstrated the frequency of numerical abnormalities of spermatozoa from infertile men with abnormal semen parameters compared with fertile controls.

METHOD

Sperm cells from 10 infertile patients were investigated for disomy rates of sex chromosomes and chromosome 18 and diploidy by fluorescence in situ hybridization (FISH). All patients showed oligoasthenozoospermia with sperm counts 3-20 x 10(6)/ml and motile rates 0-40%.

RESULTS

Regarding XY disomy, a significantly higher frequency was found in 8 of 10 patients as compared to normal fertile men. The disomy rates of chromosome 18, XX, YY, and diploidy rate were not increased.

CONCLUSIONS

There is an association between male infertility and embryo with aneuploidy of sex chromosomes. Counseling about possible genetic risks should be provided to the infertile couples planning assisted reproduction treatment.

p53 gene mutations are associated with shortened survival in patients with advanced non-small cell lung cancer: an analysis of medically managed patients

Mutations in the p53 gene are common in many cancers. Nevertheless, the relationship between mutations of this tumor suppressor gene and patient survival in non-small cell lung cancer (NSCLC) remains unclear. Interpretation of prior studies of patient outcomes are complicated by the inclusion of both surgical and nonsurgical patients. To better isolate the potential effects of p53 gene mutations per se on tumor progression, we chose to examine patients with advanced disease in whom surgery was not performed (stages IIIA, IIIB, and IV). We have used PCR-denaturing gradient gel electrophoresis, a sensitive and specific method for the detection of a variety of p53 mutations in cytology or biopsy specimens, to evaluate the prognostic significance of p53 gene mutations in nonsurgical patients with advanced NSCLC. In 70 consecutive medical patients, p53 mutations were found in 29 cases (41%) at the time of initial diagnosis. Followed prospectively, patients with p53 mutations had a significantly reduced survival time after diagnosis than those without mutations (median survival, 17 versus 39 weeks; P = 0.0003) independent of other clinical factors. This abbreviated survival occurred in both patients who received chemotherapy (n = 39, P = 0.002) or best supportive care (n = 31, P = 0.018). These results indicate that mutations of the p53 gene in patients with NSCLC who do not undergo surgical resection portends a significantly worse prognosis.

Does amniotomy influence the prognosis of babies in cases with severe chorioamnionitis? Report of a twin pregnancy with varying outcome

We report our experience in a woman with a twin pregnancy. The patient suffered severe Escherichia coli chorioamnionitis and the outcomes were different between the two babies after birth. The first baby had only a mild infection, but the second suffered sepsis and subsequent perinatal death. These differences in outcome appeared to be due to amniotomy performed for the first baby after late labor stage I to augment uterus contractions. Removal of infectious amniotic fluid from the amniotic cavity might thus have prevented the spread of the chorioamnionitis. E. coli sometimes causes severe infection during pregnancy and the perinatal period. In this case, a large number of enteropathogenic E. coli (serotype O-6) was cultured from blood, stool, pharyngeal swab, gastric juice and puncture fluid from the thoracic cavity of the second baby. O-6 is classified an enterotoxigenic strain mainly causing diarrhea because of endotoxin released from bacteria. O-6 has not hitherto been reported as a cause of severe infection in chorioamnionitis and perinatal sepsis.

[Two-step tuberculin skin test in nurse students and hospital employees]

Booster phenomenon (recall effect) of tuberculin skin test, which disturbs diagnosis of tuberculous infection, is prevalent among BCG vaccinated population. We retested 34 nurse students whose initial tuberculin reaction was smaller than 30 mm by erythema (Group A) and 53 hospital employees whose initial reaction was smaller than 20 mm by erythema (Group B). Among the people whose diameter of erythema was less than 10 mm by the first test, 88 percent (8/9) of group A and 43% (6/14) of group B showed reaction 10 mm < or = by erythema and among those whose induration was < 10 mm, 54% (6/11) of group A and 48% (12/25) of group B showed reaction 10 mm < or = in the second testing. Mean and standard deviation of [the difference between the diameter of the 2nd and the 1st testing] was +7.3 +/- 11.8 mm in group A, +9.8 +/- 11.1 mm in group B by erythema and +2.6 +/- 5.9 mm in group A, +2.9 +/- 5.1 mm in group B by induration. These results indicate that booster phenomenon is highly prevalent among the tested group and there can be no appropriate criteria to distinguish new infection and booster phenomenon. Though two-step tuberculin skin test is recommended to get rid of booster phenomenon. Only a little is known about the value of this test to diagnose new infection in Japanese population, majority of whom being BCG vaccinated. Further investigations are required to apply two-step tuberculin skin test for diagnosis of new infection among hospital employees and health care workers in Japan.

The integrin alpha(9)beta(1) binds to a novel recognition sequence (SVVYGLR) in the thrombin-cleaved amino-terminal fragment of osteopontin

The integrin alpha(9)beta(1) mediates cell adhesion to tenascin-C and VCAM-1 by binding to sequences distinct from the common integrin-recognition sequence, arginine-glycine-aspartic acid (RGD). A thrombin-cleaved NH(2)-terminal fragment of osteopontin containing the RGD sequence has recently been shown to also be a ligand for alpha(9)beta(1). In this report, we used site-directed mutagenesis and synthetic peptides to identify the alpha(9)beta(1) recognition sequence in osteopontin. alpha(9)-transfected SW480, Chinese hamster ovary, and L-cells adhered to a recombinant NH(2)-terminal osteopontin fragment in which the RGD site was mutated to RAA (nOPN-RAA). Adhesion was completely inhibited by anti-alpha(9) monoclonal antibody Y9A2, indicating the presence of a non-RGD alpha(9)beta(1) recognition sequence within this fragment. Alanine substitution mutagenesis of 13 additional conserved negatively charged amino acid residues in this fragment had no effect on alpha(9)beta(1)-mediated adhesion, but adhesion was dramatically inhibited by either alanine substitution or deletion of tyrosine 165. A synthetic peptide, SVVYGLR, corresponding to the sequence surrounding Tyr(165), blocked alpha(9)beta(1)-mediated adhesion to nOPN-RAA and exposed a ligand-binding-dependent epitope on the integrin beta(1) subunit on alpha(9)-transfected, but not on mock-transfected cells. These results demonstrate that the linear sequence SVVYGLR directly binds to alpha(9)beta(1) and is responsible for alpha(9)beta(1)-mediated cell adhesion to the NH(2)-terminal fragment of osteopontin.

Is angiotensinogen gene polymorphism associated with hypertension in pregnancy?

OBJECTIVE

To determine whether a state of hypertension in pregnancy in the Japanese can be predicted in the early period based on detection of the M235T variant of the angiotensinogen gene, alone or with other factors.

METHODS

A total of 313 Japanese pregnant women were divided into 3 groups on the basis of their angiotensinogen genotype: TT, MT, and MM. Hypertension in pregnancy was diagnosed for 33 patients in all. For each group, we sought to determine what factors increased the risk of the disease.

MAIN OUTCOME MEASURES

The angiotensinogen M235T variant, mean arterial pressure (MAP) before the 12th gestational week, body mass index (BMI) before pregnancy, age at delivery, parity, a familial history of hypertension, and development of preeclampsia or gestational hypertension were considered.

RESULTS

The frequencies of the allele T were the same among preeclampsia, gestational hypertension, and normal subjects. In TT subjects, a high incidence of gestational hypertension was found for women with MAP > or = 90 mm Hg, high or low BMI before pregnancy > or = 22.0 or < 18.0, and maternal history of hypertension. In MT subjects, women who showed MAP > or = 90 mm Hg or who were above 36 years old at delivery had a high incidence of gestational hypertension. Preeclampsia could not be predicted in either group.

CONCLUSIONS

Hypertension in pregnancy cannot be predicted on the basis of the M235T variant of angiotensinogen gene alone. However, gestational hypertension is associated with combinations of other factors. In contrast, it is virtually impossible to predict the development of preeclampsia.

[A Japanese case of Poland-Möbius syndrome]

We herein report a Japanese case of Poland-Möbius syndrome. The patient was a 19-year-old female. She was the product of a full-term forceps delivery. Birth weight was 2500 g. She had a defect of the right pectoral muscle, and syndactyly of the right hand. When she was 10 days old, facial diplegia, bilateral abducens nerve palsy, and bilateral ptosis were also noted. She was admitted to our hospital at 19 years of age. On physical examination, she had microsyndactyly of the right hand, and her right pectoralis major muscle was absent. Neurological examination revealed bilateral abducens nerve paresis, mild impairement of the upward and adducting movement of both eyes and bilateral facial weakness and atrophy of the left side of her tongue. Her karyotype was normal. Neither R 1 nor R 2 response was evoked in the blink reflex on either side. Brain MRI disclosed thin facial nerves and atrophy of the pons and medulla. Therefore, she was diagnosed as a case of Poland-Möbius syndrome. In this case, the facial nerves were considered to be hypoplastic.

Intraperitoneal seeding of ruptured hepatocellular carcinoma: case report

We report a solitary intraperitoneal recurrence in a long-term survivor after rupture of hepatocellular carcinoma. Ultrasonography demonstrated the finding of a lobulated mass with a "mosaic" appearance. The patient underwent resection of this implant and is currently disease free. We emphasize the importance of periodic surveillance of disseminated metastases of this condition.

p53 mutations in tumor and non-tumor tissues of thorotrast recipients: a model for cellular selection during radiation carcinogenesis in the liver

Concerns over cancer development from exposure to environmental sources of densely ionizing, high linear energy transfer (LET) radiation, such as alpha-particles from radon, is a current public health issue. The study of tumors attributable to high LET irradiation would greatly augment our insights into the biological mechanisms of carcinogenesis. Chronic low-dose-rate internal exposure to alpha-radiation from thorium dioxide deposits following intravascular administration of the radiographic contrast agent Thorotrast is known to markedly increase the risk of cancer development, especially that of hepatic angiosarcomas and cholangiocarcinomas. Although the mechanism is hypothesized to be via cellular damage, DNA being a major target, wrought by the high LET alpha-particles, the specific genes and the actual sequence of events involved in the process of transforming a normal cell into a malignant one are largely unknown. To shed some light on the molecular mechanisms of cancer development during a lifetime exposure to alpha-radiation, we analyzed the most commonly affected tumor suppressor gene in humans, p53, in 20 Thorotrast recipients who developed cancer, mostly of hepatic bile duct and blood vessel origin. Of the 20 cases, 19 were found to harbor p53 point mutations. Moreover, the accompanying non-tumor tissues from these patients also had p53 mutations, albeit at lower frequency. The distribution pattern of the point mutations was significantly different between the non-tumor and tumor tissues, with most mutations in malignant tissues located in the highly conserved domains of the p53 gene. Our results support the idea that p53 mutations are important in the genesis of Thorotrast-induced tumors but that these point mutations are a secondary outcome of genomic instability induced by the irradiation. Additionally, non-tumor cells harboring p53 mutations may gain some survival advantage in situ but mutations in the domains responsible for the formation of structural elements critical in binding DNA may be necessary for a cell to reach full malignancy.

[A case of Lyme disease with the triad of neurologic manifestations (meningitis, radiculoneuritis, facial nerve palsy) and dermatitis of the nail roots]

A 23-year-old man experienced dysesthesia of the distal parts of four limbs and spilling of drinking water from the right corner of his mouth. He also experienced low grade fever, headache, and nausea. Neurological examination showed weakness of the right frontal, orbicularis oculi and orbicularis oris muscles, atrophy and weakness of the interosseous muscles in both upper limbs and dysesthesia in the distal parts of four limbs. Laségue's sign was also positive on the left side. Examination of CSF showed lymphocytic pleocytosis and an increase of total protein. Serum antibody against Borrelia garinii was positive as determined by ELISA. The patient was diagnosed as a case of Lyme disease. His symptoms were not alleviated by administration of ceftriaxone (2 g/day) for 15 days, and dermatitis of nail roots appeared. Following administration of penicillin G at a high dose (12 million units/day) for 20 days, both neurologic symptoms and dermatitis were alleviated. Since B. garinii was reported to move preferentially toward the sites of low temperature, dermatitis of nail roots may be one of the characteristic features of Lyme disease caused by B. garinii.

Motion-transparent inducers have different effects on induced motion and motion capture

To assess the relationship among the underlying mechanisms of induced motion, motion capture, and motion transparency, directions of the former two illusions in the presence of motion-transparent inducers were examined. Two random-dot patterns (inducers) were superimposed upon a stationary disk (target), and moved in orthogonal directions. Either a high-contrast target (for induced motion) or a low-contrast target (for motion capture) was used. The task was to report the perceived direction of the target. The depth order of inducers was controlled either by adding binocular disparity or by asking the subject to report subjective depth order. For induced motion, the target appeared to move in the direction opposite to the inducer that had a disparity closer to the target; when there was no difference in disparity, induced motion occurred oppositely to the 'vector sum' of the inducers' directions. For motion capture, the target was captured by the inducer that subjectively appeared behind. These results suggest that the underlying mechanism of motion capture utilizes the output from the process for motion transparency, whereas induced motion has no clear relationship to the output of the process for motion transparency.

Use of new magnetic attachments for implant-supported overdentures

A newly designed magnetic attachment system for external hexed implants with a standard abutment platform has been developed. This system has certain definite advantages over bar attachments and ball attachments, which are frequently utilized for implant-supported overdentures. Especially, it can be applied to cases with reduced vertical dimension of occlusion because the total height of the magnet and the keeper is only 2.3 mm when assembled. In addition, detrimental lateral stresses to the fixture are greatly alleviated due to very low attractive forces horizontally. Favorable clinical results using this new magnetic attachment system have been obtained, and it may be considered a useful addition to overdenture therapy using any external hexel implant with a standard abutment platform, such as the Brånemark implant system.

A jitter after-effect reveals motion-based stabilization of vision

A shaky hand holding a video camera invariably turns a treasured moment into an annoying, jittery momento. More recent consumer cameras thoughtfully offer stabilization mechanisms to compensate for our unsteady grip. Our eyes face a similar challenge in that they are constantly making small movements even when we try to maintain a fixed gaze. What should be substantial, distracting jitter passes completely unseen. Position changes from large eye movements (saccades) seem to be corrected on the basis of extraretinal signals such as the motor commands sent to the eye muscle, and the resulting motion responses seem to be simply switched off. But this approach is impracticable for incessant, small displacements, and here we describe a novel visual illusion that reveals a compensation mechanism based on visual motion signals. Observers were adapted to a patch of dynamic random noise and then viewed a larger pattern of static random noise. The static noise in the unadapted regions then appeared to 'jitter' coherently in random directions. Several observations indicate that this visual jitter directly reflects fixational eye movements. We propose a model that accounts for this illusion as well as the stability of the visual world during small and/or slow eye movements such as fixational drift, smooth pursuit and low-amplitude mechanical vibrations of the eyes.

Effects of diabetes and hyperglycemia on disaccharidase activities in the rat

BACKGROUND AND METHODS

To elucidate the effect of hyperglycemia on disaccharidase activities, the specific and total activities of the disaccharidases were measured in the intestinal mucosa and kidney cortex of diabetic and hyperglycemic rats. The diabetes was induced with an intraperitoneal injection of streptozotocin (60 mg/kg). The rats were made hyperglycemic with an intravenous instillation of a solution containing 40% dextrose monohydrate at a rate of 1.5 ml/h for 24 h.

RESULTS

The blood glucose level was 387+/-45 mg/dl and 382+/-35 mg/dl (mean +/- standard deviation) in diabetic and hyperglycemic rats, respectively. In diabetic rats the intestinal maltase, sucrase, and lactase activities were significantly higher than those in control rats. Similarly, disaccharidase activities in hyperglycemic rats were significantly higher than those in control rats. The renal maltase activity in diabetic rats was significantly lower than that in control rats. The maltase activity in hyperglycemic rats, however, was not significantly different from that in control rats.

CONCLUSIONS

These results suggest that 1) hyperglycemia directly increases the activities of intestinal maltase, sucrase, and lactase; 2) hyperglycemia does not influence renal maltase activity; and 3) hyperglycemia is partly responsible for increased activities of intestinal disaccharidases in diabetes mellitus.

[A case of early-onset cortical cerebellar atrophy with rhythmic skeletal myoclonus in the left upper limb]

A 19-year-old man developed progressive unsteady gait and speech disturbance two years ago. He recently noticed muscle twitches in the left limb. Neurological examination revealed scanning speech, saccadic ocular movement, ataxia of trunk and limbs predominant on the left side. Rhythmic myoclonus was present at rest around the left shoulder and arm, and amplified by raising the left arm. There was no myoclonus in the soft palate. MRI revealed only a cerebellar atrophy. This patient was diagnosed as having cortical cerebellar atrophy with rhythmic skeletal myoclonus (RSM). Tc-99m ECD SPECT showed a decrease in the blood flow of the right thalamus when the myoclonus was enhanced by raising the left upper limb, which suggests that the cerebello-thalamo-cortical system as well as Guillain-McIlaret triangle is involved in the development of RSM.

Assay of 222Rn in water samples by a modified integral counting method

22Rn activity concentrations in water collected from 163 private wells and 14 springs in Tokyo were measured with a liquid scintillation spectrometer using a modified integral counting method. The activity concentrations of 222Rn range from 0.2 to 22.9 Bq/L and average 4.8 Bq/L. The errors due to the air luminescence counts and the interferences from 220Rn and 219Rn are discussed and evaluated. 222Rn samples of 0.2 Bq/L can be assayed within an overall uncertainty of 3.1%. The liquid scintillation method involving agitation of the sample water directly with a liquid scintillation cocktail was compared with the present method and evaluated.

Identification of the ligand binding site for the integrin alpha9 beta1 in the third fibronectin type III repeat of tenascin-C

The integrin alpha9 subunit forms a single heterodimer, alpha9 beta1 that mediates cell adhesion to a site within the third fibronectin type III repeat of tenascin-C (TNfn3). In contrast to at least 3 other integrins that bind to this region of tenascin-C, alpha9 beta1 does not recognize the common integrin recognition motif, Arg-Gly-Asp (RGD). In this report, we have used substitution mutagenesis to identify a unique ligand recognition sequence in TNfn3. We introduced mutations substituting alanine for each of the acidic residues in or adjacent to each of the exposed loops predicted from the solved crystal structure. Most of these mutations had little or no effect on adhesion of alpha9-transfected SW480 colon carcinoma cells, but mutations of either of two acidic residues in the B-C loop region markedly reduced attachment of these cells. In contrast, cells expressing the integrin alphav beta3, previously reported to bind to the RGD sequence in the adjacent F-G loop, attached to all mutant fragments except one in which the RGD site was mutated to RAA. The peptide, AEIDGIEL, based on the sequence of human tenascin-C in this region blocked the binding of alpha9-transfected cells, but not beta3-transfected cells to wild type TNfn3. This sequence contains a tripeptide, IDG, homologous to the sequences LDV, IDA, and LDA in fibronectin and IDS in VCAM-1 recognized by the closely related integrin alpha4 beta1. These findings support the idea that this tripeptide motif serves as a ligand binding site for the alpha4/alpha9 subfamily of integrins.

Motion transparency in superimposed dense random-dot patterns: psychophysics and simulation

To determine the mechanism underlying motion transparency, representative examples of motion transparency are listed and possible mechanisms are suggested. Those are feature tracking, multiple spatial-frequency channels, luminance-based transparency rules, and motion energy. Next, an interesting stimulus for motion transparency is introduced, namely superimposed dense random-dot patterns, which is not explained by feature tracking or multiple spatial-frequency channels. A psychophysical experiment reveals that the occurrence of motion transparency in this stimulus depends on three luminance levels assigned to three possible combinations of component dots: (1) white dots superimposed upon white dots, (2) white dots upon black dots, and (3) black dots upon black dots. However, physical rules of luminance-based transparency fail to explain the results. Finally, a computer simulation reveals that a computational model based on motion energy quantitatively predicts the human psychophysical performance. All the results support the idea that motion-energy detection followed by spatial integration is a likely candidate for the mechanism underlying motion transparency.

Deletion of Epstein-Barr virus latent membrane protein 1 gene in Japanese and Brazilian gastric carcinomas, metastatic lesions, and reactive lymphocytes

A 30-bp deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Information on this deletion in EBV-associated gastric carcinoma (EBVaGC) is limited. The association of gastric carcinoma (GC) with EBV was examined by EBV-encoded RNA (EBER) in situ hybridization in 510 patients from Japan and 80 patients from Brazil. We studied the prevalence of 30-bp LMP1 gene deletion in EBVaGC in Japan (29 cases) and Brazil (four cases) in comparison with the corresponding EBER1-positive metastatic lesions in lymph nodes (10 cases) and EBV-infected reactive lymphocytes from dissected nonmetastatic lymph nodes (22 cases), microdissected non-neoplastic gastric mucosa of EBVaGC (five cases), and EBV-nonassociated GC (25 cases). We studied the status of the LMP1 gene by Southern blot hybridization of polymerase chain reaction products obtained after amplification with primers flanking the site of the deletion. We also performed EBV typing and LMP1 protein immunohistochemistry. EBV DNA was amplified by polymerase chain reaction in 30 of 33 EBVaGC cases, 8 of 10 metastatic carcinomas, 14 non-neoplastic tissues from 27 EBVaGC cases, and 12 of 25 non-EBV-associated GC cases with EBER1-positive lymphocytes. The 30-bp LMP1 gene deletion was observed in 23 of 26 (88.5%) cases of EBVaGC from Japan and two of four (50%) cases of Brazilian EBVaGC as compared with EBER1-positive reactive lymphocytes from 11 of 14 (78.6%) EBVaGC cases and 9 of 12 (75%) cases of non-EBV-associated GC. The variant type (the 30-bp deletion variant or nondeleted wild type) of LMP1 gene was the same among reactive lymphocytes, primary and secondary lesions of EBVaGC in all cases for which all three tissue types were studied (six of six). There was no correlation between the presence of the 30-bp deletion with depth of cancer invasion or presence of metastasis. Type A was detected in all available EBV-positive cases. The similar high incidence of 30-bp deletion in LMP1 gene in both carcinoma cells and reactive lymphocytes in EBVaGC cases suggests that this deletion may not be relevant to the pathogenesis of EBVaGC.

A retrospective evaluation of maternal serum screening for the detection of fetal aneuploidy

A retrospective evaluation of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3) levels in maternal blood in the second trimester was conducted for cases of aneuploid pregnancies identified from a series of women who underwent amniocentesis. Blood samples were collected from 1078 women just before genetic amniocentesis was performed, mainly for individuals of advanced maternal age (greater than 35 years). Twenty-five maternal serum samples from pregnant women with an aneuploid fetus, including 14 with Down's syndrome, were available for analysis of all three parameters. An algorithm to detect Down's syndrome was used for this analysis with a risk of > or = 1:299 classified as screen-positive, this being found for 20.4 per cent of the cases (220/1078). The actual Down's syndrome detection rate was 85.7 per cent (12/14), whereas the detection rate for all aneuploidies was 72.0 per cent (18/25). Those that were not detected were two cases of trisomy 21, one trisomy 18, two trisomy 13, three sex chromosome abnormalities, and one case of an additional marker chromosome. The data indicate that this tri-analyte test should be provided after thorough genetic counselling and informed decision-making regarding maternal serum screening for women who wish for a prenatal diagnosis.

Role of endogenous basic fibroblast growth factor in the healing of gastric ulcers in rats

Recently, it has been pointed out that growth factors play an important role in the healing of gastrointestinal ulcers. In the present study, we examined the role of endogenous basic fibroblast growth factor (bFGF) in the healing of gastric ulcers in the rat. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Time-dependent changes in the area and bFGF content in the ulcerated area and distribution of bFGF in the ulcerated mucosa were examined. Effects of bFGF mutein CS23 (TGP-580) and a monoclonal antibody for bFGF (MAb 3H3) on the healing of the gastric ulcers and angiogenesis in the ulcer bed were also examined. The content of bFGF in the ulcerated area increased with time as the ulcer healed and reached a maximum 7 days after ulcer formation. In the gastric ulcer bed, many cells such as fibroblasts and macrophages were positively stained immunohistochemically by anti-bFGF antiserum. MAb 3H3 (0.1 mg/rat/day, i.v.) inhibited angiogenesis in the ulcer bed and significantly delayed ulcer healing, while TGP-580 (0.001-0.1 mg/kg x 2/day, p.o.) increased the number of microvessels in the ulcer bed and accelerated the healing. These results suggest that endogenous bFGF may play an important role in the healing of gastric ulcers in the rat and that the angiogenic properties of bFGF (TGP-580) may be involved in its effect on ulcer healing.

Prevention of gastric ulcer relapse induced by indomethacin in rats by a mutein of basic fibroblast growth factor

We found indomethacin aggravates healed gastric ulcers (ulcer relapse) in rats. In the present study, we examined the effects of human basic fibroblast growth factor (bFGF) mutein CS23 (TGP-580) and histamine H2-receptor antagonists (H2-RAs) on ulcer relapse in this model. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Indomethacin (1 mg/kg/day) given s.c. for 2 weeks starting 4 weeks after the operation aggravated the healed ulcer; the areas with and without indomethacin were 4.8 +/- 1.4 and 0.4 +/- 0.3 mm2, respectively. Drugs were given orally once daily for 4 weeks starting 2 days after the operation or for the 2-week indomethacin administration period. Treatment with ranitidine (100 mg/kg), cimetidine (100 mg/kg) and TGP-580 (0.1 mg/kg) for 4 weeks accelerated the healing. The aggravation by indomethacin was significantly inhibited by pretreatment with TGP-580 and mildly inhibited by cimetidine but not ranitidine. When the drugs were co-administered with indomethacin for 2 weeks, the aggravation was significantly prevented by ranitidine and mildly inhibited by cimetidine and TGP-580. Both TGP-580 and H2-RAs can prevent the ulcer relapse induced by indomethacin but via different modes of action: TGP-580 inhibits relapse mainly by acting on the process of healing, while H2-RAs act mainly on the process of aggravation.

Role of endogenous basic fibroblast growth factor in the healing of gastric ulcers in rats

Recently, it has been pointed out that growth factors play an important role in the healing of gastrointestinal ulcers. In the present study, we examined the role of endogenous basic fibroblast growth factor (bFGF) in the healing of gastric ulcers in the rat. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Time-dependent changes in the area and bFGF content in the ulcerated area and distribution of bFGF in the ulcerated mucosa were examined. Effects of bFGF mutein CS23 (TGP-580) and a monoclonal antibody for bFGF (MAb 3H3) on the healing of the gastric ulcers and angiogenesis in the ulcer bed were also examined. The content of bFGF in the ulcerated area increased with time as the ulcer healed and reached a maximum 7 days after ulcer formation. In the gastric ulcer bed, many cells such as fibroblasts and macrophages were positively stained immunohistochemically by anti-bFGF antiserum. MAb 3H3 (0.1 mg/rat/day, i.v.) inhibited angiogenesis in the ulcer bed and significantly delayed ulcer healing, while TGP-580 (0.001-0.1 mg/kg x 2/day, p.o.) increased the number of microvessels in the ulcer bed and accelerated the healing. These results suggest that endogenous bFGF may play an important role in the healing of gastric ulcers in the rat and that the angiogenic properties of bFGF (TGP-580) may be involved in its effect on ulcer healing.

Perceptual filling-in at the scotoma following a monocular retinal lesion in the monkey

Although no visual inputs arise from the blind spot, the same visual attribute there as in the visual field surrounding the blind spot is perceived. Because of this remarkable "perceptual filling-in," a hole corresponding to the blind spot is not perceived, even when one eye is closed. Does the same phenomenon occur in the case of a scotoma in which visual inputs are lost postnatally due to a retinal lesion? We report that it did: in the macaque monkey, behavioral evidence for filling-in at a scotoma produced by a laser-induced monocular retinal lesion was obtained. The visual receptive fields of neurons in the primary visual cortex (V1) in and around the representation of the visual field corresponding to the scotoma were also mapped, and no clear difference between the retinotopic organization of this part in V1 and that found in the normal visual field was found. Also, perceptual filling-in was found to occur only two days after the lesion. These findings suggest that the normal visual system possesses a mechanism that yields filling-in when some part of the retina is damaged, and that such a mechanism requires no topographical reorganization in V1.

Surface representation in the visual system

Perception of surface accompanies the impression that a certain area of the visual field is occupied by some quality, such as color, brightness and transparency. This does not mean, however, that information about surface quality must be obtained throughout the area. It has been shown in many situations that our visual system has ability to interpolate information obtained at the border of the surface and to perceive homogeneous surfaces. The most dramatic demonstration of this is the perceptual filling-in at the blind spot. In order to understand the neural representation of surface in the visual system, we conducted a series of experiments using macaque monkeys. First, we examined if neurons in the primary visual cortex (V1) respond when a homogeneous surface is presented on the receptive field. Neurons representing the parafoveal visual field were tested and it was found that about one third of neurons showed significant responses when the cell's receptive field was contained in a homogeneous surface. Then we examined neuron activities in the retinotopic representation of the blind spot in V1. Although there is no retinal input in the blind spot, a homogeneous surface is perceived within the blind spot as a result of filling-in. We tested whether neurons in this region were activated when a homogeneous surface was perceived in the blind spot as a result of filling-in. We found some neurons in V1 were activated by stimuli which lead to the filling-in. These results indicate that when a surface area is perceived, neurons are activated throughout the region in V1 topographically corresponding to the perceived surface and not restricted to the region representing the border of the surface.

[Effects of lansoprazole on indomethacin-induced gastric bleeding and mucosal lesions in rats]

The effects of lansoprazole given intravenously on indomethacin-induced gastric bleeding and mucosal lesions were investigated in rats in comparison with those of omeprazole, famotidine and ranitidine. Lansoprazole inhibited gastric bleeding induced by indomethacin with an ID50 value of 0.29 mg/kg. Omeprazole and famotidine significantly inhibited gastric bleeding, but ranitidine provided negligible inhibition. A correlation was found between the inhibitory action of lansoprazole on gastric bleeding, and acid secretion, and its inhibitory action on gastric bleeding was almost completely abolished by adding 50 mM-HCl to the gastric perfusate, suggesting that lansoprazole's inhibitory action on gastric bleeding was mainly due to its antisecretory action. Lansoprazole inhibited the development of gastric lesions induced by indomethacin with an ID50 value of 0.10 mg/kg, whereas histamine H2-receptor antagonists did not display a potent inhibitory effect. ID50 values for omeprazole, famotidine and ranitidine were 0.69, 2.58 and 24.6 mg/kg, respectively. These results indicate that lansoprazole has a potent inhibitory action on indomethacin-induced gastric bleeding and mucosal lesions and that it is useful in the treatment of acute gastric mucosal lesions.

[Effects of intravenous lansoprazole on acute gastric mucosal lesions and acid secretion]

The effects of lansoprazole given intravenously on gastric mucosal lesions, gastric bleeding and acid secretion were investigated in rats in comparison with those of omeprazole, famotidine and ranitidine. Lansoprazole inhibited the formation of gastric mucosal lesions in rats induced by water-immersion stress or aspirin with ID50 values of 0.26 and 0.99 mg/kg, respectively, and also inhibited gastric bleeding induced by hemorrhagic shock or water-immersion stress with ID50 values of 0.46 and 1.22 mg/kg, respectively. Lansoprazole was more potent than omeprazole, famotidine and ranitidine in inhibiting gastric mucosal lesions and hemorrhagic shock- or stress-induced bleeding. Famotidine and ranitidine showed negligible inhibition of water-immersion stress-induced gastric bleeding. Lansoprazole strongly inhibited water-immersion stress-stimulated acid secretion in rats, whereas famotidine and ranitidine did not show a potent inhibitory effect. These results indicate that lansoprazole exerts prominent inhibitory actions against the formation of gastric mucosal lesions and gastric bleeding by inhibiting acid secretion, and they show that it is superior to histamine H2-receptor antagonists in inhibiting stress-induced gastric bleeding.

Comparison of lens biochemistry and structure between BSO-treated and glucocorticoid-treated developing chick embryos

In this paper various changes in glutathione level, which were influenced by balance of its synthesis, degradation, transport and utilization, were analysed in chick embryos administered with glucocorticoid (GC) or buthionine sulfoximine (BSO; an inhibitor of glutathione synthesis). When BSO (30 mumol egg-1) was administered twice to chick embryos on day 14 and 15, the GSH in both the lens and the liver decreased to 15-20% and 30-40% of the age-matched control level, respectively, between 24 and 48 hr after the second treatment, then began to recover. Although this decline in the GSH level in these tissues was greater and more prolonged in embryos treated with BSO than with GC, the former embryos maintained lens transparency even up to 144 hr by a visual examination. However, histological changes in the lens occurred after 96 hr and more significantly 144 hr after second administration of BSO. The changes mainly consisted of pale epithelial cells on the anterior peripheral surface of the lens, irregular height of the epithelial cells at the equator, clefts between the epithelium and the cortex and swelling of almost all the cortical fibers. These observations may suggest that BSO treatment could produce the beginning of a cataract. Embryos with GC-cataract revealed the following changes at 48 hr: loss of transparency, elevation of LPO (TBA-reacting substance) in the lens, the blood and the liver. These were not observed in BSO-treated embryos during the experimental period. The GC-cataract may well depend on the generation of LPO. BSO cataract, having a distinct mechanism compared to that caused by GC, develops more slowly in GSH-depleted lenses. The BSO-treated chick embryos will be a useful model to screen the risk factors which accelerate cataract formation.

Neuroendocrine pharmacology of three serotonin releasers: 1-(1,3-benzodioxol-5-yl)-2-(methylamino)butane (MBDB), 5-methoxy-6-methyl-2-aminoindan (MMAi) and p-methylthioamphetamine (MTA)

Serotonin (5-hydroxytryptamine, 5-HT)-releasing drugs are important experimental tools to examine the role of serotonergic nerve terminals in the secretion of hormones. The drugs 1-(1,3-benzodioxol-5-yl)-2-(methylamino)butane (MBDB), 5-methoxy-6-methyl-2-aminoindan (MMAI) and p-methylthioamphetamine (MTA) have been suggested to be 5-HT releasers. The present study characterized MBDB, MMAI and MTA by using their effects on the secretion of the hormones adrenal corticotrophin (ACTH), corticosterone, prolactin, oxytocin and renin. The time course of the effect of MBDB, MMAI and MTA (5 mg/kg, i.p.) showed that the peak effect on plasma ACTH occurred 10 min after the injection, whereas the prolactin response did not reach a maximum until 30 min after injection. MBDB increased plasma renin concentration within 10 min, whereas the effect of MTA was significant only at 30 min after injection. All three 5-HT releasers decreased HR (within 5 min) and blood pressure (at 15 min after injection). MBDB, MMAI and MTA increased plasma ACTH, corticosterone, prolactin and renin levels in a dose-dependent manner, whereas no changes were observed in plasma vasopressin concentrations. MTA and MMAI, but not MBDB, significantly increased plasma oxytocin concentrations in a dose-dependent manner. Pretreatment of rats with fluoxetine blocked the ACTH response to MBDB and MMAI, but not to MTA. The prolactin response to all three 5-HT releasers was blocked by fluoxetine. The oxytocin response to MTA and MMAI was inhibited by fluoxetine. The renin responses to all three 5-HT releasers were not significantly inhibited by fluoxetine. The results suggest that MBDB, MMAI and MTA can increase the secretion of several hormones, at least in part, through stimulation of serotonergic neurotransmission. However, these three 5-HT releasers seem to have effects on other (and as yet uncharacterized) mechanisms that can stimulate the secretion of some hormones.

Assimilation-type and contrast-type bias of motion induced by the surround in a random-dot display: evidence for center-surround antagonism

As a mechanism to detect differential motion, we have proposed a model of "a motion contrast detector" that has a center-surround antagonistic receptive field with respect to the direction of motion. Supporting evidence has been obtained in the studies of induced motion, motion capture, and motion aftereffect. In order to obtain further evidence in a more strictly controlled situation, we examined the perceptual bias of motion in a center stimulus induced by another, surrounding motion. By using a stochastic random-dot display configured in a center-surround concentric fashion, we measured the % signal in the center stimulus that made the stimulus perceptually stationary in the presence of a moving surround. Measurements were done for various stimulus sizes and eccentricities. The amount of bias changed as a function of stimulus size and eccentricity. At several eccentricities, smaller stimulus sizes tended to yield assimilation-type biases, whereas larger sizes tended to yield contrast-type biases. However, a spatial scaling procedure revealed that the amount of bias was a simpler function of "scaled" stimulus size that was obtained by dividing the physical size by a scaling factor at each eccentricity. In the scaled profile, assimilation-type bias changed to contrast-type bias with increasing size, reached the peak of contrast-type bias at a certain size, and decreased slightly with further increasing size. Furthermore, a model of a difference of Gaussians, DOG, function well approximated the behavior of the profile. From these results, we concluded that the process specific to perceiving relative motion is mediated by a motion contrast detector, which is possibly located in area MT.

Laparoscopic-assisted creation of a vagina

The applicability of laparoscopy for colpopiesis using pelvic peritoneum was examined in two women with the Mayer-Rokitansky-Kuster-Hauser syndrome. Using a modification of laparoscopic guidance proved advantageous for safe dissection of the vesicorectal space and accurate suturing of the pelvic peritoneum without laparotomy. A sufficient vaginal cavity was achieved in both patients. This modification of the original procedure, featuring introduction of a laparoscope, thus provides effective and safe conditions for creation of a new vagina.

Role of capsaicin-sensitive sensory neurons and nitric oxide in the protective effect of lansoprazole, a proton pump inhibitor, on the gastric mucosa in rats

The mucosal protective effect of lansoprazole, a proton pump inhibitor, was examined in ethanol- and acidified taurocholate-induced rat gastric lesion models. The formation of gastric lesions was markedly inhibited by prostaglandin E2 but hardly inhibited by cimetidine, ranitidine and famotidine. Lansoprazole (3-30 mg/kg, p.o.) inhibited the formation of gastric lesions in a dose-dependent manner, with ID50 values of 8.5 (ethanol) and 4.1 mg/kg, p.o. (acidified taurocholate). The protective effect of lansoprazole was significantly decreased by functional ablation of capsaicin-sensitive sensory neurons or prior administration of indomethacin or N(omega)-nitro-L-arginine methyl ester (L-NAME), a selective inhibitor of nitric oxide (NO) synthesis. The inhibitory effect of L-NAME was antagonized by prior administration of L-arginine, a substrate of endogenous NO, but not D-arginine. The antisecretory effect of lansoprazole on the basal acid secretion in pylorus-ligated rats was not affected by any of these treatments. Lansoprazole (5 and 15 mg/ml) administered directly into the gastric chamber obviously increased both the production of NO in the mucosa and mucosal blood flow, which was prevented by pretreatment with L-NAME. These results suggest that capsaicin-sensitive sensory neurons, NO and prostaglandins are involved in the mucosal protection afforded by lansoprazole possibly via an increase in mucosal blood flow, but are not involved in the antisecretory action of lansoprazole.

Detection of p53 gene mutations in cytopathology and biopsy specimens from patients with lung cancer

In order to ascertain the feasibility of detecting p53 gene mutations in patients with lung cancer in a nonsurgical diagnostic setting before starting treatment, we screened for p53 gene mutations in tumor specimens obtained using diagnostic methods such as fiberoptic bronchoscopy, thoracentesis, and percutaneous needle aspiration. We examined 206 specimens from 66 patients diagnosed with primary lung cancer at Hiroshima University Hospital between October 1991 and July 1993 using the polymerase chain reaction/denaturing gradient gel electrophoresis technique. p53 gene mutations were found in 64 of 159 (40%) cytologically positive specimens, but in none of 47 cytologically negative specimens. The PCR-based assay did not increase the sensitivity of the cytopathologic examination in detecting malignant cells. The type and location of the p53 gene mutation was the same in cytologically positive specimens obtained by different methods, but from the same patient. Of the 66 patients, p53 gene mutations were found in 27 (41%) at the time of the first nonsurgical diagnostic examination: 7 of 12 (58%) with small cell carcinoma, 9 of 20 (45%) with squamous cell carcinoma, and 11 of 34 (32%) with adenocarcinoma of the lung. The incidence of p53 gene mutation for each histologic subtype was comparable to previously published data examining surgically and/or autopsy-obtained specimens. These results indicate that detection of p53 gene mutations in a nonsurgical, diagnostic setting is feasible. This technique will make it possible to assess the significance of p53 gene mutations in relation to survival and response to therapy before starting treatment, in future prospective studies.

A new type of familial central diabetes insipidus caused by a single base substitution in the neurophysin II coding region of the vasopressin gene

We studied the genetic basis of familial neurohypophyseal diabetes insipidus in a Japanese family. The members had polyuria and a deficiency of plasma vasopressin (AVP). Polymerase chain reaction (PCR) amplified exons of the AVP-neurophysin-II gene were subcloned and sequenced. Exons 1 and 3 were normal, but nucleotide 1884 Guanine (G) in exon 2 was substituted with Thymine (T), which induced a substitution of glycine (Gly) for valine (Val). To examine the presence of this mutation in the affected subjects, we designed two mutated primers. One of them induced a new endonuclease restriction site in the PCR fragments from normal, and the other induced a new endonuclease restriction site from patients with the mutation. DNA fragments from two affected members of this family were amplified with this primer, and the PCR products were digested by endonuclease and resolved by electrophoresis. The results indicated that these subjects had both normal and mutant alleles, indicating that the mutation was heterozygous. We concluded that this mutation caused neurohypophyseal diabetes insipidus in this family.