Selective vagal rhizotomies: a new dorsal surgical approach used for intestinal deafferentations.

We have developed a dorsal intracranial surgery that is minimally invasive and gives excellent access to either afferent or efferent vagal rootlets to produce selective deafferentations or deefferentations in the rat. We have combined this new unilateral afferent rhizotomy with a contralateral celiac branch cut (to completely deafferent the intestines) and a duodenal catheter placement 4 cm distal to the pylorus. Animals were maintained with 17 h/day access to a nutritionally complete liquid diet. Measures of first meal size, daily intake, and body weight before and after both surgeries indicated that animals with unilateral vagal deafferentiations recovered as fast and completely as sham-operated controls. Intraduodenal oleate (1.2 kcal) infusions reduced the size of the first meal in surgical controls (by 64%; P < 0.01) but not in the deafferented rats. A dual wheat germ agglutinin-horseradish peroxidase/Fluorogold protocol provides verification of sensory and motor lesions. The selective vagal deafferentation provided by the new surgery offers a useful model for determining gastrointestinal sites of nutrient detection and separating pre- and postabsorptive consequences of a meal.

Male postpubertal facial growth in Class II malocclusions.

Maxillary and mandibular postpubertal growth changes were assessed from lateral cephalograms taken when subjects were 16 and 20 years of age. The sample consisted of 39 male subjects with no previous orthodontic treatment who exhibited Class II skeletal characteristics. Significant increases in mean maxillary and mandibular measurements were observed over the age period studied. Mean mandibular growth (Co-Gn) was approximately three times that of maxillary growth (Co-A). Total mandibular growth observed between 16 to 20 years of age was approximately 4.3 mm. The mandible appeared to rotate anteriorly superiorly, reflected by a mean reduction in mandibular plane angle of 1.47 degrees and a greater increase in posterior versus anterior face height. There were not statistically significant changes in incisor angulation. Mean growth changes in this Class II sample were comparable to those previously reported for male subjects with Class I malocclusions over the same age period, suggesting a similarity in postpubertal development between these two groups.