Complications of early-onset insulin-dependent diabetes mellitus in Blacks and Indians

Blacks and Indians with early-onset insulin-dependent diabetes mellitus (IDDM) were studied in order to assess the prevalence of acute and chronic complications. Of the 92 Blacks almost 70% developed ketoacidotic coma on one or more occasions, whereas 50% of the 41 Indians manifested this complication. Most of the chronic complications were related to duration of IDDM. Retinopathy was found in 14% of the Black and 22% of the Indian patients, nephropathy in 3% and 7% and neuropathy in 22% and 32% respectively. Compared with findings in other studies, IDDM in these population groups is not associated with a particularly high prevalence of chronic complications.     

Effect of phentolamine methanesulfonate upon uterine contractility induced by l-norepinephrine pregnancy

Twelve women with normal pregnancies at term were studied by means of continuous records of amniotic fluid pressure during advanced prelabor. Patients received continuous infusions of l-norepinephrine at two different concentrations, 0.05 μg per kilogram per minute and 0.08 μg per kilogram per minute. Phentolamine methanesulfonate was administered in a single intravenous injection of 5 mg. followed by a continuous infusion of the same drug. Uterine activity increased when norepinephrine was administered in any dose. When phentolamine was infused before norepinephrine, uterine activity also increased, but the increments were less marked than in the preceding group. When phentolamine was administered after norepinephrine effects were established, previous increments in uterine activity diminished. The effects of phentolamine, an alpha blocking agent, suggest that the action of norepinephrine on uterine contractility may be mediated through alpha receptors.     

Fusion of Semliki Forest virus infected aedes albopictus cells at low pH is a fusion from within

Summary Herein, it is shown for the first time that the mechanism of fusion followed in Aedes albopictus cells infected with Semliki Forest virus induced by low pH exposure is a fusion from within. Several parameters were studied disclosing that the development of the fusion capacity of the cells is directly related to the synthesis of viral specific products. These findings were further substantiated by utilizing various chemicals to inhibit viral specific events during infection, protein synthesis and maturation. Removal of exogenous virions produced at 16 hours post infection by proteinase K digestion clearly revealed that the viral proteins located at the cell surface and not the exogenous virions were responsible for the fusogenic activity. The presence of these viral proteins at the cell surface was disclosed by immunofluorescence employing anti-SFV antibodies elicited in rabbits. Additional evidence for the participation of the viral proteins at the cell surface in the fusion reaction was obtained by Bromelaine digestion which inhibited the fusion and tunicamycin treatment which only partially inhibited the fusion but revealed the inevitable presence of the E₁ protein.With 2 Figures     

Mechanisms of sensory adaptation in the isolated utricle

The occurrence of receptor adaptation in utricular afferent fibers is now widely recognized. The experiments reported here explored the basic mechanisms of adaptation at the level of the receptor organ. Spike discharges from single utricular afferent fibers were recorded in isolated labyrinths of an elasmobranch, during three types of stimulation: (a) tilts in the gravity field, (b) vibrations, and (c) electrical polarization delivered through the nerve filaments from which recordings were also made. Experimental evidence supported the conclusion that polarization affects the discharge by acting at the level of the spike triggering mechanism, the point of the afferent fiber at which impulses normally arise. Three types of afferent fibers have been described: Types I and II fire spontaneously and show phasic-tonic responses to tilts. Type III fibers do not have spontaneous activity and respond to tilts in a phasic manner. Adaptation to polarizing currents was observed in all afferent fibers. Type II fibers adapted slowly to vibrations whereas types I and III afferent fibers did not. The functional processes situated near the spike triggering site of the sensory axon is referred to as neural whereas those occurring at earlier stages of transduction are called preneural. Adaptation to tilts exhibited two successive components: an early, fast phase and a late, slow one. Our results suggested that these phases can be related to the mechanisms of preneural and neural adaptation, respectively. Because the time course of adaptation to polarizing currents was similar in different afferent fibers, we concluded that preneural adaptation was the origin of the differences among afferent fibers that allowed their classification into phasic, phasic-tonic, and tonic groups. No attempts were made to separate the influence of mechanical coupling and transduction in the production of preneural adaptation.