A new strategy of gene trapping in ES cells using 3'RACE

"Gene trapping" in embryonic stem (ES) cells is a novel approach to identify a series of genes in mammals concomitant with the production of the corresponding mutant mice. However, this approach is currently unable to identify genes that are not expressed in ES cells. Here we describe a strategy to identify gene trapping clones which is not based on expression of a reporter gene. It uses the neor gene which lacks a polyadenylation signal and has a splice donor signal. Expression of the neor gene as fusion transcripts with the 3' end containing the polyadenylation signal of tagged genes allows the identification of these clones by 3' rapid amplification of the cDNA end in undifferentiated ES cells, even if the genes are not expressed in ES cells. Amplification was observed in about 25% of G418-resistant clones. Sequence analyses suggested the amplifications represent gene trapping events. The feasibility of this approach was further assessed by analysing one clone, PAT-12, in detail.

Natural history of intracranial cavernous malformations

The authors have reviewed the clinical records of 110 patients with intracranial cavernous malformations diagnosed by histological examination and/or magnetic resonance imaging over a mean follow-up period of 4.71 years. These cases were divided, based on their presentation, into a hemorrhage group, a seizure group, and an incidentally diagnosed group. The rate of subsequent symptomatic bleeding was investigated in relation to age at onset, sex, and location of the initial lesion. A high rate of subsequent symptomatic bleeding episodes was found in the hemorrhage group, especially among younger females. The nonhemorrhagic-onset cases had a very low incidence of bleeding. The outcome was generally good, except in patients with lesions in the basal ganglia and brainstem. These findings will be helpful in planning a rational therapeutic strategy for intracranial cavernous malformations.

A study on urine cotinine for the evaluation of smoking cessation

Two branch offices of enterprise T in the same city engaged in service and sales were selected at random for this study on the evaluation of smoking cessation education using the urine cotinine concentration (U-Cot) measured by ion pair reversed-phase high performance liquid chromatography (IP-R-HPLC). Branch A conducted a smoking cessation education program; branch B did not. By comparison of the results obtained from questionnaires and U-Cot analyses at both the offices, we investigated the validity of evaluation by U-Cot. The results were as follows: I. Smokers 1. At branch A, a self-reported 20-year-old female non-smoker was confirmed to smoke about 5 cigarettes per day by her high concentration (292.8) of U-Cot at pre-education. 2. At branch A, the self-reported average number of cigarettes smoked daily (ANCSD) at 6 months post-education showed a significant decrease in comparison with that at pre-education. 3. At branch A, U-Cot at post-education showed a significant decrease in comparison with those at 2 weeks, 2 months, and 6 months pre-education in descending order. 4. Two male subjects who were strongly suspected to have submitted a false number of cigarettes smoked prior to urine sampling (NCSPU)/ANCSD self-reports at 6 months post-education were confirmed to have done so by the U-Cot values at the fourth period, which were in excess of 500, and the discrepancy between the ratio ([value at post-education in 6 months] divided by [value at pre-education]) of U-Cot (1.52, 1.47, respectively) and that of NCSPU/ANCSD, (0.00)/0.00). 5. At branch A, discrepancies between the success rate of quitting smoking in self-reported NCSPU/ANCSD at 6 months (17.0%) and in U-Cot (12.2%) were observed. At branch B, no such discrepancies were observed. 6. At branch A, office workers at 6 months post-education who had, but not those who had not, previously considered the health damage caused by smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. At branch B, no such differences were observed. 7. At branch A, office workers at 6 months post-education who had previously considered quitting smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. Those who had not previously considered quitting showed a significant decrease in ANCSD, but not in NCSPU or U-Cot.(ABSTRACT TRUNCATED AT 400 WORDS)

Ovarian teratomas in mice lacking the protooncogene c-mos

Parthenogenesis has been suggested to be tightly coupled with development of ovarian teratomas. Indeed, ovarian tumors developed in c-mos-deficient female mice, which are characterized by the parthenogenetic activation of oocytes. The tumors appeared at a frequency of 30% between 4 and 8 months of age, and did not develop in younger or older mice. Most of the tumors were benign and consisted of multi-focal cysts most notably with mature ectodermal components, but also with mesodermal and endodermal components. One among 17 tumors observed consisted of extra-embryonic tissues alone, and two bore malignant components with metastasis to peritoneal organs. The results strongly suggest the involvement of c-mos mutations in human germ cell tumors.

[Diagnostic and therapeutic problems in vestibular neuronitis: clinical implications for sudden vertigo]

We defined sudden vertigo as a sudden, unilateral peripheral vestibular dysfunction. The criterion for its diagnosis is a single episode of vertigo without cochlear and central symptoms. Among 20 patients with sudden vertigo there was no difference in clinical aspects between those with CP (canal paresis) (CP% > or = 25%) and those without CP (CP% < 25%). This suggests that sudden vertigo with CP is due to sudden vestibular dysfunction with predominant involvement of the lateral semicircular canal. Basically, vestibular neuronitis is considered to be due to acute unilateral neuropathy of the vestibular nerve. However, since we have no routine examination for evaluating vestibular nerve function, sudden vertigo with CP should be diagnosed as vestibular neuronitis. We then assessed the prognosis of sudden vertigo with CP (vestibular neuronitis). About two years after the onset of CP 4 of 10 patients had recovered. However, patients with persistent CP had a handicap in their everyday life because of the dizziness induced by head movements. The possibility of recovery of vestibular function in response to steroid therapy may improve the prognosis in vestibular neuronitis.

Pressure- and thermally-induced reversible changes in the secondary structure of ribonuclease A studied by FT-IR spectroscopy

Fourier transform infrared (FT-IR) spectroscopy combined with a resolution enhancement technique has been used to characterize pressure and thermal effects on the secondary structure of ribonuclease A. The experiments were performed at pD 7.0 with 50 mg/mL protein solution in D2O buffer. According to the observed changes in the amide I' band, secondary structure elements such as alpha-helices, beta-sheets, and turns are cooperatively disrupted by application of either pressures above 570 MPa at 30 degrees C or temperatures above 60 degrees C at 0.1 MPa. Pressure- and thermally-denatured ribonuclease A are fully unfolded and do not contain any residual secondary structures. Both the structural changes are intrinsically reversible, although the pressure-induced transition shows a hysteresis. It is found that nonnative turn structures are formed prior to the appearance of the native secondary structure in the folding from the pressure-unfolded state. The structural features upon the pressure-induced unfolding are additionally characterized by the interesting behavior of hydrogen-deuterium exchange at high pressure. Most of the backbone amide protons protected at atmospheric pressure, which are involved in the alpha-helices and beta-sheet, are exchanged with solvent deuterons in the pressure range where the two secondary structural elements are virtually identified as intact. There is a possibility that, for ribonuclease A, application of high pressure up to 570 MPa induces such a partially unfolded state as has native-like secondary structure but permits solvent to be highly accessible to the internal regions.

Favorable course of steroid-responsive nephrotic children with mild initial attack

The course and prognosis of idiopathic nephrotic syndrome has thus far not been found to be predicted from the severity of the manifestations at the onset. Among 66 steroid-responsive nephrotic children, eight were asymptomatic without edema and identified by chance proteinuria on a urinary screening program. The selectivity index for proteinuria (a clearance ratio of IgG to transferrin) was 0.10 or less in all of the five children examined. All of the eight children responded quickly to the prednisolone therapy. Grades of proteinuria and hypoalbuminemia were lower in the asymptomatic children than in the symptomatic children who presented with edema. Median proteinuria levels were 2.0 versus 4.2 g/day/m2 (P < 0.01), respectively, and mean serum albumin levels were 2.2 +/- 0.3 versus 1.8 +/- 0.4 g/dl (mean +/- SD; P < 0.01), respectively. None of the eight asymptomatic children relapsed for at least one year after completion of the prednisolone treatment, while, in contrast, 30 of 58 symptomatic nephrotic children relapsed during the same one-year period (P < 0.01). These findings suggest that, among steroid-responsive nephrotic children, those with mild manifestations without edema may have a milder disease and show an extremely favorable clinical course.

Femoral peak bone mass and osteoclast number in an animal model of age-related spontaneous osteopenia

BACKGROUND

SAMP6 was developed as a murine model of age-related spontaneous osteopenia characterized by low peak bone mass. A morphometric study of the growing femur in SAMP6 and sex-matched SAMP2 at 10 days to 4 months of age was done to examine the pathogenic process related to osteopenia.

METHODS

Age-related changes in cortical bone thickness, femur score, trabecular bone volume, thickness of epiphyseal growth plate, number of osteoclasts, and osteoclast surface were measured with a computerized image analyzer. Osteoclasts were examined cytomorphometrically after TRAP (tartrate resistant acid phosphatase) staining of the femoral sections.

RESULTS

Cortical bone thickness and femur score increased significantly with age, while trabecular bone volume decreased significantly. Comparing mean values of cortical bone thickness, femur score and trabecular bone volume, we noted significantly lower mean values in SAMP6 than in SAMP2 mice. These significant inter-stain differences first became evident in 20-40-day-old mice, but there was no significant difference in thickness of the epiphyseal growth plate between the two strains. The mean values of the number of osteoclasts per unit bone surface length and of the osteoclast surface in SAMP6 were significantly greater than in age- and sex-matched SAMP2. Histograms of distribution of size of osteoclasts of 40-day-old male mice revealed that larger ones were more frequently seen in SAMP6. Furthermore, the ratio of osteoclasts/TRAP positive cells free in the bone marrow cavity was significantly higher in SAMP6 than in SAMP2.

CONCLUSION

Activated bone resorption may play a role in the osteopenia seen in SAMP6.

[Effect of intra-arterial and local administration of MCNU on cerebral malignant gliomas]

Twenty-six patients with cerebral malignant glioma (7 cases of astrocytoma Grade 3, and 19 of astrocytoma Grade 4) were treated by intra-arterial and local administration of MCNU. Nineteen patients were treated in combination with local radiation in a dose of 60 Gy. Intra-arterial administration of MCNU was performed by puncture of the ipsilateral common carotid artery and injection of 25mg of MCNU in 20 ml of physiological saline. Local administration of MCNU was performed by puncture of the Ommaya reservoir placed within the cavity after tumor resection. Objective tumor regression was observed on computerized tomography (CT) scans after intra-arterial and/or local administration of MCNU combined with radiotherapy in three of seven patients who had evaluable enhanced lesions on CT after surgery. It was also observed after chemotherapy alone in one of three patients with evaluable lesions. The response rate was 42.9% among patients treated with MCNU in combination with radiotherapy, and 33.3% in patients treated with MCNU alone. In two patients, local administration of MCNU induced brain edema, which was transient and caused no neurological sequelae. One patient suffered mild thrombocytopenia after seven intra-arterial doses of MCNU, however, no myelosuppression requiring administration of gamma-GCSF or blood transfusions was observed. These findings suggest that intra-arterial and local administration of MCNU can be expected to serve as effective and non-myelosuppressive chemotherapy in patients with cerebral malignant gliomas.

Assessment of auditory and vestibular functions after vestibular neurectomy for Menière's disease

Fourteen patients (12 Meniere's disease, one delayed endolymphatic hydrops and one labyrinthitis) suffering from intractable vertigo were treated with retrosigmoid vestibular neurectomy (RSVN) in our institute. Dizziness was controlled completely in all patients. Hearing was preserved in 91.7% of the cases with pure tone threshold deteriorating by more than 10 dB in one case, remained unchanged in 10 cases and improved in one case during long term observation. Substantial decrease of tinnitus was observed in 78.6%. Vestibular compensation was chronologically analyzed with a stabilometer, ENG and vestibular rotation test (0.01-0.64 Hz). Vestibular compensation under static conditions was accomplished within 2 weeks, except for spontaneous nystagmus measured in the dark. Asymmetry of vestibulo-ocular reflex was noted 2 weeks after the operation but had disappeared after 4 weeks. However, for over 2 years the VOR time constant remained lower (4.3-5.2 s) than the pre-operative value (8.2 s). Electro-cochleogram (ECoG) was recorded before and after RSVN. The -SP/AP ratio tended to increase after RSVN in the operated ear, though there was no change in the contralateral ear. The efferent olivo-cochlear bundle was thought to play a potential role in this increase of the -SP/AP ratio.

Responses of locus coeruleus neurons to caloric stimulation in rats

We examined the effects of caloric stimulation on the neuronal activity of the locus coeruleus (LC) and of the vestibular nucleus complex (VNC) in urethan-anesthetized rats. The single unit activity of neurons in the LC and VNC was extracellularly recorded. A polyethylene tube for caloric stimulation was inserted into the middle ear cavity on the ipsilateral side. Through the tube, the middle ear was irrigated by hot (44 degrees C), cold (30 degrees C), and ice (4 degrees C) water. The majority of neurons in the VNC showed excitation by middle ear irrigation with hot water and inhibition by ice-water irrigation. The responses occurred during caloric stimulation and disappeared immediately after the cessation of the stimulation. The results suggest that the responses of VNC neurons to caloric stimulation directly reflect changes in primary vestibular afferent activity. On the other hand, the predominant effect of caloric stimulation with hot and cold water on LC neuronal activity was inhibitory. The suppression of LC neuronal activity occurred approximately 1 min after the cessation of the caloric stimulation and persisted for 3-5 min. The results suggest that LC neurons receive processed vestibular signals. Motion sickness and vestibular dysfunction induced by caloric stimulation cause emesis, which is known as vestibulo-autonomic response. The vestibulo-autonomic syndrome can be prevented by amphetamine, a noradrenaline releaser. Therefore, the inhibitory response of noradrenergic LC neurons to vestibular stimulation may be involved in the vestibulo-autonomic response.

Clinical investigation of the vestibular cortex

This study attempted to identify the vestibular cortex that is involved in the perception of vestibular vertigo in the human brain. We used single-photon emission computed tomography (SPECT) to measure regional cerebral blood flow (rCBF) in two cerebrovascular patients with nystagmus-sensation dissociation, which is known as brisk caloric nystagmus without simultaneous sensation of vertigo. Both patients had ischemic lesions involving mainly the parieto-temporal lobe in the nondominant hemisphere. It is suggested that the parieto-temporal lobe in the nondominant hemisphere contains the vestibular cortex which is a center for the perception of vertigo due to vestibular stimulation.

Elevated serum levels of 3-deoxyglucosone, a potent protein-cross-linking intermediate of the Maillard reaction, in uremic patients

3-Deoxyglucosone (3-DG) has been identified as an intermediate of the Maillard reaction in vitro. We measured serum 3-DG levels using gas chromatography/mass spectrometry and found a marked elevation in serum 3-DG levels in uremic patients compared with healthy subjects. The uremic patients with diabetes showed significantly higher serum concentrations of 3-DG than those without diabetes. 3-DG was demonstrated to be a potent protein-cross-linking agent in the reaction with lysozyme, leading to browning, fluorescence formation and polymerization of the protein by formation of advanced glycation end products (AGE). The increase in serum 3-DG levels in the uremic patients suggests that 3-DG may be responsible for the development of uremic complications by promoting the formation of AGE.

Intracranial cavernous malformations and skin angiomas associated with middle fossa arachnoid cyst: a report of three cases

Three cases of multiple intracranial cavernous malformations and skin angioma associated with middle fossa arachnoid cyst are reported. Though no relation was confirmed in the pathogenesis of these lesions, this combination could be a new entity of neurocutaneous phacomatosis.

Changes in Fos and Jun expression in the rat brainstem in the process of vestibular compensation

By means of immunohistochemical technique, we examined the changes in Fos and Jun expression after unilateral labyrinthectomy (UL) in the rat brainstem. We observed Fos-like immunoreactivity (-LIR) in the ipsilateral medial vestibular nucleus (ipsi-MVe), the contralateral prepositus hypoglossal nucleus (contra-PrH) and the contralateral inferior olive beta subnucleus (contra-IOb) 1 h after UL. Then, Fos expression in the contra-PrH and the contra-IOb disappeared 3 days after surgery. However, we still found the residual expression in the ipsi-MVe, which disappeared within 7 days. On the other hand, no Jun-LIR was detected in the vestibular or vestibular-related nuclei before or after the operation. Fos expression in the MVe, PrH and IOb was induced immediately after UL. Then, the Fos expression disappeared in accordance with the development of the vestibular compensation. These findings suggest that the transient Fos expression in the vestibular and vestibular related nuclei is a trigger of vestibular compensation.

Vestibular modulation of the septo-hippocampal cholinergic system of rats

Effects of vestibular stimulation on the in vivo release of hypothalamic histamine and hippocampal acetylcholine (ACh) were investigated in urethan-anesthetized rats, using a brain microdialysis method. Changes in glutamate concentration in the medial vestibular nucleus (MVN) were also monitored by a microbiosensor technique using a glutamate oxidase-embodied platinum electrode. Caloric stimulation with hot water increased the glutamate release in the MVN, while that with ice water decreased it. It is evidenced that glutamate is a neurotransmitter between afferent vestibular nerve and the MVN. Electrical stimulation of the round window evoked the release of hypothalamic histamine and hippocampal ACh and these effects were inhibited by the blockade of second-order vestibular neurons by the pre-injection of 6,7-dinitroquinoxaline-2,3-dione (DNQX), an antagonist of non-N-methyl-D-aspartate (non-NMDA) glutamate receptors, into the ipsilateral vestibular nucleus. Caloric stimulation with both hot and ice water increased the release of hypothalamic histamine and hippocampal ACh. It is suggested that both the histaminergic and cholinergic systems were activated by the imbalance of intervestibular activities. Depletion of neuronal histamine by alpha-fluorometylhistidine (FMH), an irreversible inhibitor of histamine synthesis, did not suppress the vestibular evoked release of hippocampal ACh. In contrast, caloric stimulation did not evoke hypothalamic histamine release in rats treated with ethylcholine aziridiniun ion (AF64A), a putative cholinotoxin. All these findings suggest that the vestibular information activated the histaminergic neurons via the activation of the cholinergic neurons and this neuronal circuit was involved in the vestibulo-autonomic response.

[Multivariate analysis of everyday handicap of patients with dizziness]

A preliminary questionnaire consisting of 30 questions was developed to evaluate handicaps in everyday life for 105 patients with dizziness. Factor analysis divided the questions into 5 principal factors of handicap due to dizziness: 1) disturbance of social activity, 2) body motion precipitating dizziness, 3) limitation of physical activity, 4) emotional disturbance, and 5) disturbance of interpersonal communications. The score of each factor was calculated as the sum of the scores of three principal questions in the corresponding factor. There was no contribution of clinical diagnosis, patient's age or gender, or duration of the disease to the score of each factor. Thus, it is concluded that the reorganized questionnaire which consists of three principal questions in 5 factors can be used for evaluating dizziness handicaps in everyday life. The score of the emotional factor in patients with Meniere's disease was higher than that for other vestibular disease. The score of the body motion factor in patients with vestibular neuronitis was higher than that for vertebro-basilar artery insufficiency. Thus, the re-organized questionnaire can also be used for evaluating the contribution of each factor to dizziness handicaps in everyday life.

Hemodynamic adaptations at birth and neonates delivered vaginally and by Cesarean section

In order to assess the possible influence of differences in delivery mode on cardiovascular adaptation at birth, we measured left ventricular output and its regional distribution in the major organs sequentially using an echographic technique during the first 96 h of life. We studied 27 normal newborns, of whom 15 were delivered vaginally and 12 by cesarean section. We also measured umbilical arterial and venous catecholamine concentrations. The umbilical arterial epinephrine and norepinephrine concentrations in the infants delivered vaginally were significantly greater than those in the infants delivered by cesarean section (epinephrine 1,195 +/- 208 vs. 565 +/- 81 pg/ml, p < 0.05; norepinephrine 11,832 +/- 3,819 vs. 5,153 +/- 1,400 pg/ml, p < 0.05). The left ventricular output and its regional distribution showed a similar pattern in the two groups, and there were no significant differences between them. These results indicate that the capacity of infants delivered by cesarean section to tolerate cardiovascular changes during the early neonatal period is comparable to that in infants delivered vaginally, even though there are significant differences in the catecholamine surge between these groups.

Nystagmus measured by ENG after stapes surgery

Much attention has been paid to hearing results after stapes surgery, but the risks of vestibular disturbance has not been extensively studied. Postoperative spontaneous nystagmus was measured daily at bedside by portable ENG in order to evaluate the vestibular damage from stapes surgery. Thirteen patients underwent primary stapedotomy or stapedectomy from August 1, 1992 to June 30, 1993. Nystagmus toward the operated ear was observed in 3 cases, that toward the opposite ear in 2 cases, that changing from toward the operated ear to toward the opposite ear in 2 cases, that changing from toward the opposite ear to toward the operated ear in 2 cases and no nystagmus in 4 cases. There was no relationship between duration of nystagmus and that of dizziness. Nystagmus was thought to be due to the following: i) inner ear damage by operation, ii) postoperative perilymphatic fistula, iii) floating footplate, and iv) stimulation of hair cells by high potassium ion in the perilymph due to blood flow into the inner ear.