Genetically determined thymus enlargement in the early life in BUF/Mna rats.

BUF/Mna (B) rat is a mutated strain, having much larger thymus than WKY/ NCrj (W), ACI/NMs (A), and F344 (F) rats throughout their life-span. Rats of the latter 3 strains have normal sized thymuses, being less than 5.3 in the thymus to body weight ratio (mg/g), when they were killed at 6 weeks of age. Genetic segregation of large thymus size in the B strain at 6 weeks of age was studied by crossing B rats with W, A or F rats. All of 3 types of the F1 hybrid rats between the B strain and the other strains showed intermediate thymus ratios between those of both parental strains. In F2 rats between the B and W strains, the distribution of thymus ratios showed about 5 different peaks. These findings might indicate that two polymeric autosomal loci, thymus enlargement-1 (Ten-1) and thymus enlargement-2 (Ten-2), can enlarge the thymus size in B rats. Histometrically, whole thymus and cortex areas of the B rats were 2-5 times larger than the W rats during 6-12 weeks of age, but medulla areas were slightly different between the strains, showing that larger thymuses in B rats were mainly due to the enlarged cortex areas.

Sialolithiasis in children: report of four cases.

Sialolithiasis in children is rare. Four cases of sialolithiasis in the submandibular gland occurring in children < or = 10 years old are reported. True and distal oblique occlusal radiographs were found to be useful for detection of the sialolith. A review of the literature on sialolithiasis in children is presented.

Limitations of panoramic radiography in the detection of bone defects in the posterior wall of the maxillary sinus: an experimental study.

Some lesions in the maxillary sinus may be adequately detected by panoramic radiography. The present study was designed to evaluate the ability of panoramic radiography in detecting experimental bony defects in the posterior wall of the maxillary sinus by comparison with Waters' projection and CT. Bony defects in the mediosuperior and medioinferior regions of the posterior wall were readily detected by panoramic radiography, but those in the laterosuperior or centre were not. It is concluded that there are limitations to the detection of bony defects in the posterior wall of the maxillary sinus by panoramic radiography alone. It is recommended that this technique should not be used for the detection of small osteolytic lesions in the maxillary sinus.

A case of neurilemmoma in the infratemporal fossa showing the antral bowing sign.

A case is reported of a neurilemmoma which arose in the right infratemporal fossa of a 23-year-old male. A benign tumour was suspected when bowing of the posterior maxillary antral wall was observed on CT.

Experimental comparison of radiographic techniques in the detection of maxillary sinus disease.

The radiographic examination of the maxillary sinus is usually accomplished by the Waters' projection. However, some lesions, such as the mucous retention cyst, postoperative maxillary cyst and maxillary sinus carcinoma, as well as some lesions extending into the maxillary sinus, may be shown by panoramic radiography. The present study was conducted to confirm the ability of panoramic radiography in the detection of maxillary sinus disease. The representation of a globular radiopaque mass at different locations in the maxillary sinus of a dry skull was compared in Waters' and panoramic projections. A mass with a diameter of 10 mm situated on the posterior wall or floor of the maxillary sinus was shown better by panoramic radiography. The Waters' projection was less effective; the mass, especially on the floor of the sinus, was not clearly demonstrated due to superimposition of the maxillary molar teeth.