[An experimental study of the effects of drilling with dental high speed turbine on culture cells (in vitro) (author's transl)]

A drilling at 500 000 R.P.M. with a dental high speed turbine was made either to a tissue culture bottle or to a test tube, in which mouse L fibroblasts were grown for 2 days with YLH medium supplemented with 10% bovine serum, in order to examine the effects of high speed drilling to the cells in vitro, Experiments were carried out with the following three conditions; (1) Drilling of outer surface of the glasswares at the inner surface on which the cells were attached, with a water coolant, (2) Drilling of the same place without a water coolant, and (3) Drilling of a remote area of the glasswares where no cells were grown. The last experimental condition permitted to give a sole effect of vibration accompanied with the drilling. Rates of cell multiplication and morphological observation were obtained on 2 days and 5 days after the glasswares were drilled. Rates of cell multiplication showed no change between the experimental conditions and control. This means that heat generation, vibration and/or their compound effects during drilling did not deter cells from growing. Morphological change of the cells due to the drilling was parallel to the results of cell multiplication except the drilling without a water coolant. When drilled without a water coolant, the cells around the drilled area was deteriorated and died after 24 hours. However, most of the cells away from the drilled area were not affected. The present results can not directly apply to the drilling in dental clinic, since in vivo condition has more complicated situation, some of which can not be simulated in in vitro environment. However, the in vitro results can surely be important information in resolving drilling effects in vivo.

Clinical observations of juvenile nonprogressive muscular atrophy localized in hand and forearm

Twenty-seven patients with juvenile nonprogressive muscular atrophy localized in the hand and forearm were analyzed. The clinical characteristics were juvenile male occurrence, insidious onset, specific distribution of localized muscular atrophy and a stationary course. On electromyography, denervation voltage (or giant NMU) is found in the atrophied muscles and sometimes in contralateral nonatrophied ones. Sensory disturbance was not remarkable. Although the etiological factor was not known, strenuous exercise of arms in sports was noted frequently in the history.

Effect of fasting on two postheparin plasma triglyceride lipases and triglyceride removal in obese subjects

A new method was used for selective measurement of lipoprotein lipase and hepatic lipase in human postheparin plasma. Hepatic lipase was assayed in 1.0 M NaCl withour addition of serum, and the activity of lipoprotein lipase was determined in 0.1 M NaCl after immunoprecipitation of hepatic lipase with specific antiserum. The activity of both these enzymes and the total lipolytic activity were measured in plasma samples taken during a 4-h infusion of heparin. Each of the activities was related to basal serum triglyceride concentration and to the fractional removal constant (K) of Intralipid in 13 obese subjects before and after prolonged fasting. During a normal isocaloric diet the lipolytic activities showed a biphasic response to heparin infusion in all subjects. A peak activity was reached within 30 minutes ("early response") and thereafter the lipase activities decreased to a constant level maintained during the rest of the heparin infusion ("late response"). The early response of lipoprotein lipase showed a significant inverse correlation with the basal serum triglyceride level (r = -0.85) and a significant positive correlation with the fractional removal rate of Intralipid (r = 0.84). The late response of lipoprotein lipase was not related to either of these parameters. The early response of hepatic lipase was not correlated with basal triglyceride concentration or Intralipid removal, whereas the late response of this enzyme showed a significant negative correlation with the removal rate of Intralipid (r = -0.82). After fasting for several days the acute response of all lipolytic activities to heparin was markedly decreased or totally abolished, but the magnitude of the late response was similar to that seen in the fed state. The fractional removal rate of Intralipid was slightly increased by starvation. All correlations between postheparin plasma lipases and serum triglyceride concentration and removal disappeared in fasting subjects. It is concluded that the rapidly releasable lipoprotein lipase probably reflects the activity of the tissue enzyme(s) which is responsible for the primary removal of very low density lipoprotein (VLDL) triglycerides and chylomicrons. It is probable that this component of the postheparin plasma lipolytic activity is derived from the endothelial lipoprotein lipase pool. This enzyme plays a key role in the efflux of plasma triglycerides under normal conditions, and it is thus one determinant of plasma triglyceride level. Prolonged fasting obviously changes the triglyceride removal sites and mechanism but does not impair the removal efficiency.

Chronic inflammatory polyradiculoneuropathy

The diagnostic criteria, natural history, nerve conduction characteristics, pathology, laboratory features, and efficacy of corticosteroid treatment have been evaluated personally in 53 patients with chronic inflammatory polyradiculoneuropathy (CIP) who were followed up for an average of about 7.5 years. These were patients whose monophasic neurologic deficit had not crested by 6 months, patients with recurrences, and patients with a steady or stepwise progression. The typical features of CIP include absence of an associated disease, frequent history of preceding infection or receipt of foreign protein, and tendency to involve cranial, truncal, and proximal as well as distal limb structures and to have diffusely slow conduction velocity of peripheral nerves. The most marked slowing is often very proximal. The pathologic features include serous edema, mononuclear cell infiltrates (especially in perivascular areas, but without evidence of vasculitis), macrophage-induced segmental demyelination, and hypertrophic neuritis. If our patients are representative, complete recovery occurs only infrequently; about 60% of patients are able to be ambulatory and work, 25% become confined to a wheelchair or become bedridden, and approximately 10% die from their disease. Although the bulk of the pathologic changes affect spinal roots and proximal nerves, the brain and spinal cord may be involved also. Degeneration into linear rows of myelin ovoids is the predominant type of myelinated fiber degeneration of the sural nerve at the ankle.

Giant axonal neuropathy. A clinical entity affecting the central as well as the peripheral nervous system

An 8-year-old girl had progressive muscle weakness and a unique posture of the lower limbs, areflexia, distal sensory impairment, and remarkably kinky hair. Histologic examination of the sural nerve showed giant axons filled with neurofilamentous masses. The clinical and histologic findings resembled those of recent cases reported as "giant axonal neuropathy." Our patient's precocious puberty, Babinski's sign, and electroencephalographic abnormalities suggested central nervous system involvement. Two cases previously reported and the present one appear to represent a new clinical entity that affects the central and the peripheral nervous system.

A comparison of some demand subject searches: machine vs. human

A comparison of the results of machine and human information retrieval using MEDLARS and the printed Index Medicus indicates that at present neither method is entirely satisfactory for exhaustive literature searches. The advantages and disadvantages of machine and manual search methods are discussed, and solutions to some of the problems are suggested.