Reliability of software-based assessment of paediatric preparations for preformed metal crowns in the simulation laboratory.

PURPOSE: Using software for assessment of restorative work on typodonts in the simulation laboratory may enhance the objective evaluation of student work. The study aimed to evaluate the inter-rater and intra-rater reliability using 3-D scans from the Planmeca Emerald™ intra-oral scanner with Romexis Compare® software for assessing preparations for preformed metal crowns (PMCs). METHODS: Three operators independently recorded 3-D scans and digitally measured the features of 30 PMC preparations on typodont primary teeth (# 75). Using Romexis Compare® software, preparations were measured from mesial, distal and occlusal aspects. Measurements were repeated after 2 weeks. The intraclass correlation coefficient (ICC) was used to measure the reliability of measurements between operators and within the one operator. RESULTS: For measuring the extent of tooth reduction, there was excellent intra-rater reliability for each operator (ICC 0.96-0.99). The highest inter-rater reliability was for measurements of the occlusal surface (0.946 and 0.956), followed by the mesial surface (0.852 and 0.862) and then the distal surface (0.746 and 0.724). CONCLUSION: This method was useful and reliable for measuring features of PMC preparation, but with some limitations. Improving the software to provide specific assistance tools would empower greater uptake of this method as an adjunct to traditional visual grading tool in paediatric dentistry preclinical teaching.

Establishment of estrogen receptor-positive transplantable rat thyroid tumor cell lines in vivo.

We established 17 transplantable rat thyroid tumor cell lines from the primary thyroid tumor of rats induced by N-bis(2-hydroxypropyl)nitrosamine. Among the 17 tumor cell lines established, only two of them (D1 and G1) were estrogen receptor (ER) positive. These two cell lines were characterized with respect to transplantability, histological features, ER contents and cellular localization, and expression of ER message. The ER contents, determined by dextran-coated charcoal assay, were 13.3 and 20.7 fmol/mg protein for D1 and G1 cell lines, respectively. Scatchard plot analysis indicates that the dissociation constants (Kd) were 0.17 and 0.4 nM, respectively, for D1 and G1 cell lines. Sucrose density centrifugation analysis detected a hormone-receptor complex which sedimented at the 4S region, characteristic for ER. Immunohistological staining revealed that the ER was localized in the nuclei. The presence of ER in D1 and G1 cell lines was further confirmed by reverse transcriptase-polymerase chain reaction to detect the ER mRNA. These results demonstrated that ER is expressed in some thyroid tumors. The ER-positive transplantable tumor cell lines are useful for studying the direct effect of estrogen on thyroid tumors in vitro and in vivo.

Establishment of a rat thyroid carcinoma cell line in vitro demonstrating high DNA synthesis in response to insulin-like growth factor I.

We previously established transplantable rat thyroid carcinoma cell lines in vivo from primary thyroid tumors induced by N-bis-(2-hydroxypropyl)nitrosamine (DHPN). In the present study, an insulin-like growth factor I (IGF-I)-responsive cell line (TRTC-G1-C-A4) in culture was derived from one (well differentiated papillary type) of these carcinoma cell lines G1. TRTC-G1-C-A4 cells were found to exhibit specific saturable binding of IGF-I with a Kd of 1.16 nM at approximately 43.6 fmol/10(5) cells. Inclusion of IGF-I (10 and 50 ng/ml) in the culture medium resulted in a significant increase of [3H]thymidine incorporation and marked cell proliferation. IGF-II (10 ng/ml) and insulin (1 microgram) produced no such effects. The molecular weight of IGF-I receptors on the cell membrane was determined by Western blotting analysis, a single band of binding proteins with a molecular weight of 125 kDa being evident under non-reducing conditions. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that the TRTC-G1-C-A4 cells contained IGF-I receptor mRNA with a sequence corresponding to that determined from rat uterus. These results demonstrate that the IGF-I receptor can be expressed in a thyroid carcinoma with an important contribution to cell growth.

Ki-ras oncogene activation in transplantable rat thyroid carcinoma induced by N-bis(2-hydroxypropyl)nitrosamine.

We have established 17 transplantable rat thyroid carcinoma cell lines from primary thyroid tumors of rats induced by N-bis(2-hydroxypropyl)nitrosamine (DHPN) (Cancer Res. (1993) 53, 4408-4412). The present study was designed to evaluate point mutations in the murine c-Ki-ras gene of these carcinoma cell lines. Using PCR amplification and direct sequencing, we found that the activated form of the Ki-ras oncogene was present in 4 (23%) of a total of 17 cell lines, all the Ki-ras gene mutations being GC-->AT transitions. In three of the cell lines, the mutations occurred in codon 12 (GTP-binding domain), and in the remaining one the first nucleotide of codon 63 was affected. Histologically, three of the carcinomas with Ki-ras mutation were diagnosed as well-differentiated carcinomas, and the other as poorly differentiated carcinoma. Mutations of the ras gene are relatively uncommon in tumors of these histological types. From these experimental results, we suggest that the mutation induced by DHPN is due to damage to guanine in cellular DNA. In addition, Ki-ras activation may play an important role in the initiation of thyroid carcinogenesis.

Quantitative analysis of the spinal cord motoneuron under chronic compression: an experimental observation in the mouse.

We investigated quantitative changes in spinal cord motoneurons following chronic compression using a mouse model of cervical cord compression. Twenty-five tip-toe-walking Yoshimura (twy) mice with calcified mass lesions compressing the spinal cord posterolaterally at the C1-C2 vertebral levels were compared with five Institute of Cancer Research (ICR) mice that served as controls. Spinal cord motoneurons in the anterior grey horn between the C1 and C3 spinal cord segments were Nissl-stained and counted topographically and then analysed in relation to the extent of spinal cord compression. The number of motoneurons in C1-C3 spinal cord segments decreased significantly with a linear correlation with the transverse area of the spinal cord when the cord was compressed to 50-70% of control values. A significant reduction in the number of motoneurons occurred at the C2-C3 spinal cord segment compressed at the C1-C2 vertebral level. In contrast, at the level rostral to the C1 vertebra, the number of motoneurons increased significantly in proportion to the magnitude of compression. The current study demonstrates that a number of neurons, morphologically consistent with anterior horn cells, were observed at a rostral site absolutely free of external compression where no such cells normally exist.

Potential role of streptozotocin in enhancing ossification of the posterior longitudinal ligament of the cervical spine in the hereditary spinal hyperostotic mouse (twy/twy).

We investigated the effects of streptozotocin-induced diabetes mellitus on ossification of the posterior longitudinal ligament (OPLL) in the murine cervical spine. A genetically-bound spinal hyperostotic mouse, the tip-toe walking Yoshimura (twy) mouse, was used in these experiments. Histological examination showed that streptozotocin enhanced membranous and enchondral ossification of the posterior longitudinal ligament of the cervical spine, particularly in the area of the ligamentous enthesis. It also increased the number of alkaline phosphatase-positive osteoblast-like mesenchymal cells particularly around the enthesis, while the number of such cells was less in control twy mice and ICR mice treated with streptozotocin. The area of OPLL subsequently increased in size in streptozotocin-treated twy mice. We suggest that streptozotocin-induced diabetes enhances OPLL in the genetically-bound spinal hyperostotic mouse (twy/twy).

An analysis of vitreous tamponade effect in encircling surgery by means of finite element method.

The vitreous tamponade effect in encircling surgery was investigated by means of a finite element method. We performed the simulated encircling surgery on a computer program, which could have alternative band positions, i.e. anterior or posterior band position. Computed results revealed that the band position has a great influence on the vitreous stress distribution, and that the anterior band position is more advantageous than the posterior band position with regard to the vitreous tamponade effect. To our knowledge, this is the first numerical experiment to demonstrate the advantage of the anterior band position in encircling surgery.

Macular blood flow measured by blue field entoptic phenomenon.

A measurement system for macular blood flow using the blue field entoptoscope and a microcomputer was devised by Riva & Petrig in 1980. However, there have been difficulties in applying their system to some clinical cases, especially when subjects are aged and their responses are not reliable. A modified method suitable even for such cases is presented.

[Retinal circulation and ocular blood barrier in diabetic retinopathy].

Macular capillary blood flow velocity, the score of fluorescein angiography in posterior region and aqueous flare intensity were investigated in 38 diabetics (41 eyes) and 6 normal subjects (6 eyes) to clarify the relationship among retinal circulation, blood-retinal barrier and blood-aqueous barrier. Macular capillary blood flow velocity was measured by means of the blue field entoptic phenomenon, the score of fluorescein angiography was graded by the extent of edema in the posterior region, aqueous flare intensity was measured with a flare-cell meter. The results showed that the reduction of macular capillary blood flow is significantly associated with an increase in fluorescein angiography score and aqueous flare intensity via diabetic retinopathy (p less than 0.01).

[Autoregulation of macular capillary blood flow evaluated by the blue field entoptic phenomenon].

Autoregulation of the macular capillary blood flow was investigated using a blue-field entoptoscope and OCVM suction cup system. The perfusion pressure was reduced by elevation of the intraocular pressure with a Langham's suction cup placed on the temporal sclera. The results showed that the autoregulatory response maintains the macular capillary blood flow velocity until the perfusion pressure is reduced to approximately 25 mmHg. The Closed-loop gain of the autoregulatory response functions at a perfusion pressure as low as approximately 10 mmHg, below which it did not work well.

[Contributory factors for glaucomatous disc cupping. 4. Generalized expansion type and localized type].

It is widely recognized that there are two types progressive disc cupping in glaucoma. One of them is the localized type (L type) in which the cupping extends to a certain direction and the other is the generalized expansion type (G type) in which the cupping expands generally. We evaluated the optic disc in 86 eyes with primary open angle glaucoma (G type 44 eyes L type 42 eyes) to evaluate correlations of age and visual field defects between the 2 groups. Our study revealed that G type patients were significantly younger than those with L type when matched according to visual field defects. We also found that G type was revealed as the nasal step alone but not in L type. These results suggest that in G type, the optic nerve head is diffusely damaged by elevated intraocular pressure and the total nerve fibers are destroyed uniformly. On the other hand, in L type, the vulnerable portion of the optic nerve head is selectively damaged and nerve fibers constituting the optic rim area are destroyed. As a result, L type is likely to form cupping notch and reveal Bjerrum scotoma. These facts correspond to the anatomical structures of nerve fiber layers.

[Two cases of idiopathic preretinal macular fibrosis in children].

We report herein the findings in two patients less than 15 years old with the diagnosis of idiopathic preretinal macular fibrosis, a disorder found primarily in the older population. Only a few reports have discussed idiopathic preretinal macular fibrosis in children and its pathogenesis is still unknown. One is a 10-year-old boy and the other is a 14-year-old girl who visited our hospital with a chief complaint of blurred vision in their right eyes. Epiretinal membranes were recognized on the macular region of their right eyes. Since there was no causative factors, a diagnosis of idiopathic preretinal macular fibrosis was made. They were conservatively followed up. The vision of the boy once worsened but improved spontaneously and remained stable for three years. Because the vision of the girl worsened rapidly, vitreous surgery was performed to remove the epiretinal membrane, resulting in poor vision. It was suggested that this disorder in children should be followed up conservatively and the indication of vitreous surgery should be carefully determined.

[Analysis of the retinal blood flow by means of the blue field entoptic phenomenon and simulation of entoptic leucocytes with a personal-computer system].

A method was developed for determining the velocity of macular blood flow. Leukocytes flowing in the macular capillaries can be recognized when the retina is illuminated with blue light (blue field entoptic phenomenon). The motion of the leukocytes was simulated by a personal-computer system. The velocity of the macular blood flow was determined by adjusting the motion of the simulated corpuscles to that of the entoptically recognized leukocytes. The velocity of the maximum, minimum and mean macular blood flow were measured as 1.25 +/- 0.25, 0.42 +/- 0.11 and 0.80 +/- 0.14 mm/sec respectively. The mean coefficients of variation were 6.7%, 13.4% and 5.7% for each velocity. This method may be useful for the analysis of the retinal circulation and the diagnosis of retinal diseases.

[A case of orbital hemangiopericytoma].

A 38-year old woman presented with severe proptosis in the left eye which had been developing for more than ten years. CT scan revealed a large mass in the left orbit, therefore lateral orbitotomy was performed. The histopathology of this tumor consisted of ovoid to spindle-shaped cells tumor around a sinusoidal vascular component forming staghorn channels. This tumor was diagnosed as a hemangiopericytoma. The prognosis of orbital hemangiopericytoma including clinicopathological aspects are discussed with reference to recent reports.

[Percutaneous radiofrequency neurotomy of lumbar medial branch (facet rhizotomy)--a report of 6 cases].

We performed radiofrequency neurotomy of lumbar medial branch as a treatment of facet syndrome. Our six cases had no indication for surgical therapy, such as neuralgia, spinal canal stenosis without neurological deficit except for pain and deformed spines. Facet joint injection with regional anesthetics and steroids could not prevent their recurrent back pain. By facet rhizotomy, they could obtain relief of back pain for several months to a year. We conclude that facet rhizotomy is a more effective method for facet syndrome when a proper indication is present.

[The memory of tracheal extubation during emergence from general anesthesia].

The authors evaluated the memory of tracheal extubation during emergence from general anesthesia. We screened 3,039 consecutive patients undergoing elective surgery from November 1, 1998 to December 31, 1999. Of 3,039 patients, 1,993 were interviewed postoperatively at the anesthesia clinic and 202 had the memory of tracheal extubation. The incidence was higher in the groups of female, younger and propofol anesthesia compared to male, elder and inhalational anesthesia, respectively. The patients who were dissatisfied with anesthesia were more in the patients with the memory of tracheal extubation compared to the patients without the memory. We consider that the memory of tracheal extubation contributes to the dissatisfaction with anesthesia.

[Effect on cerebral blood flow of midazolam during modified neurolept-anesthesia].

Midazolam (0.2 mg.kg-1) was administered to ten patients undergoing neurosurgical operation and its influence on CBF was studied under modified NLA. Simultaneously, the plasma concentration of midazolam was measured. Heart rate and mean arterial blood pressure showed no significant changes after injection in comparison with the control. Cerebral blood flow (CBF) decreased for about 15-20% after 5 minutes, 10 minutes and 15 minutes in comparison with the control. However, 30 minutes later, CBF showed a trend to return to the control. This change in CBF is related to the changes of cerebro-vascular resistance. We applied cerebral oxygen extraction fraction (OEF) to evaluate cerebral metabolism. OEF was constant, showing no significant changes. It is concluded that cerebral oxygen consumption (CMRO2) has decreased together with the decrease in CBF. The plasma concentration of midazolam was 250-300 ng.ml-1 or greater after 5 minutes, 10 minutes and 15 minutes. We think that the sedative dose of midazolam can also sufficiently reduce CBF and CMRO2. The results suggest that midazolam is a safe and effective agent to use for anesthesia and provides adequate sedation for patients with intracranial hypertension.

[General anesthesia with sevoflurane and vecuronium for patients with dystrophia myotonica and progressive muscular dystrophy].

A 9 year old male previously diagnosed as progressive muscular dystrophy whose serum CPK5430IU.l-1 was very high received general anesthesia. Before anesthesia, dantrolene sodium 2 mg.kg-1 was given. Anesthesia was induced with thiamylal 100 mg and vecuronium bromide 3 mg. Anesthesia was maintained with sevoflurane (0.5%) in nitrous oxide (66%) and oxygen (33%). The course of anesthesia was uneventful. The operative time was 80 minutes. At the end of the operation, the patient recovered smoothly from anesthesia. A 46 year old female with dystrophia myotonia also received general anesthesia. The patient was diagnosed as having this disease 26 years previously. Preoperatively, the patient was suspected to have cardiac damage. Anesthesia was induced with thiamylal 100 mg, fentanyl 100 micrograms, midazolam 5 mg and vecuronium bromide 4 mg, and maintained with sevoflurane (1.0%) in nitrous oxide (66%) and oxygen (33%). Anesthesia was uneventful, but at the end of the operation, the patient could not breath fully by herself. She was placed on a ventilator and observed carefully. The endotracheal tube was removed 150 minutes after the induction of anesthesia. In these two cases, sevoflurane and vecuronium bromide were used safely.

[Assessment of anesthesia satisfaction using direct interviews at post-anesthesia clinic].

The authors studied 5,034 consecutive patients undergoing elective surgery. Preoperative, intraoperative, and postoperative variables were gathered and patient satisfaction was assessed using direct interviews at pre- and post-anesthesia clinic. Fifty-nine percent of the 4,717 responders showed satisfaction and 4% showed dissatisfaction with anesthesia. The most undesirable perioperative outcome was vomiting/nausea. Other undesirable outcomes include discomfort of urine catheter, sore throat, memory of extubation, postoperative pain and so on. Anesthesiologist can improve the quality of anesthesia by preoperative explanation and preventative management for undesirable perioperative outcomes.