In order to elucidate the developmental stages of human tooth germ during prenatal period, we examined 254 normal fetuses ranging in gestational age from six weeks to fourty weeks old histologically. Lim's developmental pattern of prenatal tooth germ was divided into three groups, the first group consisting of five grades (I, II, III, IV, V) was for the development of enamel epithelium the second group of three grades was for the deposition of dentin matrix and enamel matrix, and the third group of three grades (A, B, C) was for the growth of perifollicular bone. Some developmental progress between enamel epithelium and dental papilla could be identified by observation of the sequential development of deciduous and permanent tooth germs histologically. The following results were made. 1) The prenatal development of tooth germ showed similar weekly stages in both the maxilla and the mandible. The initial deposition of dentin matrix and enamel matrix (III-1 stage) started at 12-14 weeks of gestational age in the deciduous incisor and canine, and at 16-20 weeks of gestational age in the deciduous molars. And the initial deposition of dentin matrix and enamel matrix in the permanent first molar was at 20-22 weeks of gestational age, and that of the permanent incisor was at 34-36 weeks, and that of the permanent canine was 36-38 weeks, and of the permanent premolar was at 38-40 weeks. 2) The S-shaped curvature was characteristically found where the reciprocal induction of odontoblast and amelobast occurred actively in the developing tooth germ. Primarily pre-ameloblasts which abutted on the dental papilla differentiate the condensed mesenchymal cells into odontoblasts, and secondarily matured odontoblasts which bulged into enamel epithelium produced dentin matrix and differentiated the shrunken pre-ameloblasts into ameloblasts. 3) The mandible grew more rapidly than the maxilla during the early prenatal period. The trabecular bone from both jaws proliferated initially into labial side of developing tooth follicle and gradually circumscribed the tooth follicle lingually and mesio-distally, to form perifollicular bone resultantly.
Humans

We examined sixty-three human embryos ranged from three weeks to eight weeks of fertilization age and 117 human fetuses from eleven weeks to fourty weeks of gestational age. Anatomical structure of developing tongue could be classified into eight developmental stages. The first is the sgage of mesial swelling of tongue primordium in the fertilization age of 28~40 days (Streeter stage 13~16), the second is the stage of lateral swelling of tongue primordium in the fertilization age of 41~46 days (Streeter stage 17~18), the third is the sgage of vertical positioning of tongue in the fertilization age of 47~53 days (Streeter stage 19~21), the fourth is the transitional stage of tongue from vertical position to horizontal position in the fertilization age of 54~56 days (Streeter stage 22~23), the fifth is the stage horizontal positioning of tongue in the gestational age of 11 weeks, the sixth is the stage of protrusion of tongue in the gestational age of 12 weeks, the seventh is the stage of maturation of tongue muscle in the gestational age of 7-10 months. The development of tongue papilla characteristically progresses into three stages. The first stage is the epithelial ingrowth for the crypt formation, the second stage is the anatomical formation of vallate, fungiform and filiform papillae, and the third stage is the differentiation of taste buds in the vallate and fungiform papillae or the formation of thick spike-like keratinization at the tip of filiform papilla. We observed that the tongue primordium mainly derived from occipital myotome developed more repidly than other oro-facial structures, so it transitionally occuied the spaces of the pharynx and the posterior nasal cavity, and directly affected the formation of palate and the growth of maxilla and mandible. Whereas the tongue papilla development showed continuous developmental sequences during the fetal period.
Humans

Five fetal maxillas were obtained from the autopsy file of fetal postmortem examination, and were examined by serial micro-sections of frontal plane and horizontal plane. Especially the area around the incisive canal of the maxilla was carefully observed. The results are as follows. 1) In 5 fetal maxillas extra-dental laminas and supernumerary tooth germs which are severely malformed in shape are found in the dilated incisive canal, where prominent vessels and nerves are distributed. 2) The supernumerary tooth germs disclose almost normal histo-differentiation of odontoblast and ameloblast, and there shows relatively abundant perifollicular fibrosis in the place of perifollicular bone. 3) It is observed that the over-growth of the extradental lamina from the dental ridge of deciduous central incisor frequently tends to direct toward the incisive canal that includes prominent vessels and nerves.

No abstract available.
Ameloblastoma* ; Biopsy, Fine-Needle*

No abstract available.
Bilirubin* ; Humans ; Infant, Newborn*

No abstract available.
Hemochromatosis* ; Spleen*

No abstract available.
Mandibular Fractures ; Osteomyelitis ; Transplants

We reviewed MR angiograms to evaluate its efficacy for visualizing the renal arteries and detecting renovascular disease. 41 renal arteries in 19 patients were examined by MR angiography. 3-D time-of-flight technique was used as routine examination method for MR angiography and 2-D time-of-flight technique was added in some particular cases to visualize venous flow. Within two weeks after MR angiography was performed, 23 renal arteries in 10 patients were additionally examined by conventional angiography or intraarterial DSA. The success rates of vessel visualization on MR angiography in normal renal arteries were 100% in main 67.7% in segmental, and 11.8% in intrarenal arteries. As a result of comparative study in normal main renal arteries with MR angiograms and conventional angiograms, overall correspondence in the number and the shape was noted and the caliber discrepancy between two examination did not exceed 3.0 mm. one arteriovenous fistula with aneurysm, one stenotic artery and two occluded arteries were well evaluated One arteriovenous fistula with aneurysm, and two occluded arteries were well evaluated by MR angiography. However three stenotic lesions were misdiagnosed as occlusions on MR angiography. and the overall accuracy was 87%. We conclude that MR angiography has the potential to be a noninvasive and useful screening method for determining the number of renal arteries and for detection of abnormalities of main renal arteries.
Aneurysm ; Angiography* ; Arteries ; Arteriovenous Fistula ; Humans ; Mass Screening ; Methods ; Renal Artery*

BACKGROUND: There have been no studies of airway management strategies for difficult intubation and cannot intubate, cannot ventilate (CICV) situations in Korea. This study was intended to survey devices or methods that Korean anesthesiologists and intensivists prefer in difficult intubation and CICV situations. METHODS: A face-to-face questionnaire that consisted of a doctor's preference, experience and comfort level for alternative airway management devices was presented to anesthesiologists and intensivists at study meetings and conferences from October 2014 to December 2014. RESULTS: We received 218 completed questionnaires. In regards to difficult intubation, the order of preferred alternative airway devices was a videolaryngoscope (51.8%), an optical stylet (22.9%), an intubating laryngeal mask airway (11.5%), and a fiber-optic bronchoscope (10.6%). One hundred forty-two (65.1%) respondents had encountered CICV situations, and most of the cases were identified during elective surgery. In CICV situations, the order of preferred methods of infraglottic airway management was cricothyroidotomy (CT) by intravenous (IV) catheter (57.3%), tracheostomy by a surgeon (18.8%), wire-guided CT (18.8%), CT using a bougie (2.8%), and open surgery CT using a scalpel (2.3%). Ninety-eight (45%) of the 218 respondents were familiar with the American Society of Anesthesiologists' difficult airway algorithm or Difficult Airway Society algorithm, and only 43 (19.7%) had participated in airway workshops within the past five years. CONCLUSION: The videolaryngoscope was the most preferred device for difficult airways. In CICV situations, the method of CT via an IV catheter was the most frequently used, followed by wire-guided CT method and tracheostomy by the attending surgeon.
Airway Management ; Bronchoscopes ; Catheters ; Congresses as Topic ; Education ; Intubation* ; Intubation, Intratracheal ; Korea* ; Laryngeal Masks ; Methods ; Surveys and Questionnaires ; Tracheostomy

Achondroplasia is a rare disease and characterized by the combination of short extremities with an enlarged head and a trunk approximating normal size. We had experienced 4 cases of achondroplasia; they all showed stunted growth, short arms and legs, prominent forehead, flattening of the bridge of the nose and moderate degree of kyphcsis and one case was associated with hydrocephalus. X-ray showed the thickness of the bones and their irregular epiphyseal ends such as cupping, flaring and spurs. Intelligence seemed to be normal except one case. We had seen those patients at the age of 8 months, 6 months and 1year, 7months and 2 years, confirming achodroplasia by clinical, X-ray survey and biochemical study. Review of the references concerning achondroplasia was made briefly.
Achondroplasia* ; Arm ; Extremities ; Forehead ; Head ; Humans ; Hydrocephalus ; Intelligence ; Leg ; Nose ; Rare Diseases