General anesthesia for the provision of dental treatment to adults with developmental disability.

The management of the behavior of mentally challenged adults when providing required dental care is often a problem, whether in the dental office or in a hospital setting. Our institution has a designated program to provide required dental care to this group of patients. Because of the high incidence of poor cooperation, which may include aggressive antagonistic behavior, many of these patients are scheduled for dental care under general anesthesia with an incomplete preoperative medical assessment. The purpose of this study was to determine the impact and limitations that an incomplete medical assessment may present in the delivery of dental care under general anesthesia to these adults with developmental disability. After approval from the institutional review board, the medical records of 139 patients treated in this program between 1992 and 1994 were reviewed to determine the patient profiles, anesthesia management, and complications. The charts of these patients, who underwent dental and radiographic examination, scaling and prophylaxis, and restoration and extraction of teeth under general anesthesia, were reviewed. There were 149 procedures performed on these patients, some more than once. The mean age was 29.5 yr. Males predominated females by a ratio of 2:1. All had multiple diagnoses, medical problems, and medications. Twenty-three patients had Down's Syndrome, four had schizophrenia disorders, 42 had seizure disorders, 11 had hypothyroidism, seven had heart disease, and 14 had central nervous system and neuromuscular disorders. The remainder had a variety of diagnoses, including rare syndromes. One hundred had intravenous (i.v.), 25 had mask inhalation, and 24 had intramuscular ketamine (Ketalar) induction. Nasotracheal intubation was uneventful in 139 patients, five had difficult visualization of the larynx and intubation. Ten patients experienced intraoperative complications, including nonfatal ventricular arrhythmia, slight fall in blood pressure and hypertension (greater than 20% of preoperative value), and four individuals developed laryngospasm. In the Post Anesthetic Care Unit, five patients experienced minor airway problems resulting in a desaturation of oxygen to a level below 85%. Adults with developmental disabilities can be safely managed under general anesthesia for dental treatment in a hospital setting with minimal morbidity and without extensive preoperative investigations.

Stereological studies on the ultrastructural markers of renal tubular transport during accelerations acting along the +Gz axis.

The study was carried out on rats. Electron micrographs of the kidney obtained under +Gz accelerations were analysed. Using stereological methods the estimation of ultrastructural markers of active transport (mitochondria energy state), and passive transport (intercellular spaces and basal infolded channels) was performed in the proximal and distal tubules. The results obtained indicated that during the actions of accelerations active tubular transport was impaired as reflected by a lowering of mitochondrial energy states (similar to condensed) in the proximal and distal tubules. Widening of intercellular spaces and basal infolded channels was also observed, which suggests fluid stasis and thus impairment of passive transport.

Ultrastructural studies on diurnal variations in mitochondria in various regions of the hepatic lobule.

Stereologic studies on diurnal variations in ultrastructural manifestations of hepatic mitochondrial function in various regions of the hepatic lobules were performed. The experiments were performed on Wistar rats in May when the liver shows the maximal content of glycogen. The materials for the studies were taken at 8 am. and 10 p.m. The stereologic examinations were done according to the method of Weibel et al. The results obtained may suggest a conversion of the orthodox hepatic mitochondria to the transitional state, that is during the glycogen minimum in the rats in May. In the morning, when the glycogen deposits increased, the pericentral mitochondria are in the orthodox state. In the evening glycogen consumption due to glycogenolysis was accompanied by conversion of the mitochondria from the orthodox state to the transitional ones, which may suggest their increased metabolic activity.

The influence of muscular contractions on acetylcholine effects on nutritive blood flow in the hindpaw of dog.

In the earlier investigations it was shown that muscular exercise augmented the dilator effects of ACh in the vascular bed of the hind leg of dog. To get a closer insight into this phenonenon the effects of acetylcholine on the nutritive blood flow in contracting skeletal muscle in the dog were studied. It was found that i.a. acetylcholine administration raises the nutritive blood flow in the investigated vascular bed within about 30--36 minutes after muscular contractions. The nutritive blood flow during and following muscular contractions induced by stimuli of varying frequency was also investigated.