Renal concentration defect following nonoliguric acute renal failure in the rat

The mechanism of impaired renal concentrating ability following nonoliguric ischemic acute renal failure was studied in the rat. Fifty min of complete occlusion of the renal artery and vein with contralateral nephrectomy resulted in reversible, nonoliguric acute renal failure. Eight days following induction of acute renal failure, a defect in 30 hr dehydration urine osmolality was present when experimental animals were compared with uninephrectomized controls (1,425 +/- 166 versus 2,267 +/- 127 mOsm/kg water respectively, P less than 0.001). Comparable postdehydration plasma vasopressin levels in experimental and control animals and an impaired hydro-osmotic response to exogenous vasopressin in experimental animals documented a nephrogenic origin of the defect in urine concentration. Lower urinary excretion of prostaglandin E2 in experimental animals and a failure of cyclo-oxygenase inhibition with 10 mg/kg of indomethacin to improve dehydration urine osmolality suggested that prostaglandin E2 antagonism of vasopressin action did not contribute to the concentration defect. Postdehydration inner medullary (papillary) interstitial tonicity was significantly reduced in experimental animals versus controls (870 +/- 85 versus 1,499 +/- 87 mOsm/kg water respectively, P less than 0.001). To determine if this decreased interstitial tonicity was due to vascular mechanisms, papillary plasma flow was measured and found to be equivalent in experimental and control animals. To examine a role for biochemical factors in the renal concentration defect, cyclic nucleotide levels were measured in cytosol and membrane fragments. A decrease in vasopressin and sodium fluoride-stimulated adenylate cyclase was found in outer medullary tissue of experimental animals. In contrast, vasopressin-stimulated adenylate cyclase activity was comparable in the inner medullary tissue of control and experimental animals. Our study suggests a defect in generation of renal inner medullary interstitial solute as a mechanism of the impaired urinary concentration observed in this model of acute renal failure.

Periodic transfusions for sickle cell anemia and CNS infarction

Recurrences of CNS infarction often lead to progressive neurologic disability in sickle cell anemia. To prevent such reccurrence, a periodic blood transfusion program was begun in 1969. Currently, 27 patients are on this regimen. Before inclusion in the program, 12 patients had had one to nine CNS recurrences each. Since the program was started, two patients have had transient CNS ischemia. There were no other recurrences and none of the patients have shown progression of neurologic abnormalities. In addition, there was a striking decrease in bacterial infection and pain. We conclude that periodic transfusions are effective in preventing recurrent CNS infarction in sickle cell anemia. The benefits must be weighed against the potentially serious problem of iron overload, as evidenced by moderately elevated serum ferritin values.

Properties of an intense 40-kV neutral beam injector

The properties of an intense neutral beam injector, the modified duoPIGatron ion source, are discussed and compared with other injectors. For this source (a) beam composition for hydrogen is approximately (85+/-5) % monatomic, (b) nucleon gas efficiency is 50%, (c) the electrical efficiency of ion generation is 1.1 A/kW, and (d) up to 52% of the input power is delivered in the ion and neutral beam to a target subtending a half angle of 1.8 degrees x1.4 degrees .

Experimental study of ion beam optics in a two-stage accelerator

Hydrogen ion beam optics in a two-stage linear acceleration system is studied by examining the beam divergence as a function of the voltage and gap distribution, the beam perveance, the background gas pressure, the aspect ratio, and the total accelerating energy (60-110 keV). The system consists of four electrodes with single, cylindrical, straight-bore apertures acting as an extraction-accel-decel column. An optimum relation between the field ratio and the extraction perveance is obtained from measurements for the minimum beam divergence condition. The HWHM divergence angle is <0.3 degrees under optimum conditions. Qualitative agreement between the measurements and a previous theoretical study is noticed. A potential application of the results to high energy neutral beam injectors for fusion research is also discussed.

Opticociliary veins in a primary optic nerve sheath meningioma

A 59-year-old man developed painless visual loss in his left eye over a one-year period, with rapid progression to blindness over three months. Ocular examination of the left eye revealed proptosis, marked optic disk pallor, dilated retinal veins, and congeries of vessels at the disk margin (opticociliary veins). His right eye was unremarkable. Fluorescein angiography and histopathologic examination confirmed the presence of opticociliary veins communicating between branches of the central retinal vein and the adjacent choroidal vasculature. Primary orbital optic nerve meningioma associated with opticociliary veins was diagnosed.

Reconstitution of lipid vesicles associated with HVJ (Sendai virus) sikes. Purification and some properties of vesicles containing nontoxic fragment A of diphtheria toxin

A mixture of HVJ (Sendai virus) spike proteins, the nontoxic fragment A of diphtheria toxin, lecithin, and cholesterol was solubilized in sucrose solution containing a nonionic neutral detergent. The liposomal vesicles which formed on removal of the detergent by dialysis were purified by gel filtration and centrifugation on a sucrose gradient. The resulting purified vesicles had hemagglutinating activity, hemolytic activity and, after solubilization, the enzymic activity of fragment A. The vesicles had no cell fusion activity. Electron microscopy showed that both the outside and inside of membranes of the vesicles were associated with the spikes. When the vesicles were freeze-fractured, no large aggregates of particles were seen on either face. Such fragment A-containing lipid vesicles (liposomes) with HVJ spikes bound to mamalian cell membrane and released their fragment A into the cytoplasm causing cell death. Neither fragment A-containing liposomes without spikes nor empty liposomes with spikes were toxic.

Ion beamlet steering by aperture displacement for a tetrode accelerating structure

Steering of a single beamlet of ions in a tetrode accelerating structure as a function of both aperture displacement and the ratio of acceleration to extraction voltage (Gamma) has been measured, and the results are compared to the steering predicted by a modified linear theory. Although the data contain the predicted features of (1) null steering for a particular value of Gamma and (2) a directional change in steering through this point, the steering was also observed to be nonlinear in nature. A conjecture as to the cause of this nonlinearity is given, and the implications of these findings to beamlet steering in a multibeamlet source are discussed.

Repair of major cranio-orbital defects with an elastomer-coated mesh and autogenous bone paste

We present a method for repairing defects in the craniofacial region in which an elastomer-coated mesh is used as a template with bone paste. The method was developed by animal experimentation first, and then successfully used in the maxillofacial and mandibular regions. We have used this method to repair 16 craniofacial defects with satisfactory results, and complications have been kept to a minimum.

Serial propagation of Creutzfeldt-Jakob disease in guinea pigs

The transmission and serial propagation of Creutzfeldt-Jakob disease from man to guinea pigs are reported. The latency, symptomatology, and morphology of the infection during the first four passages are presented. The incubation period between the first and subsequent passages was halved. One hundred percent take, morbidity, and mortality were achieved in all inoculated animals. All guinea pigs developed a subacute spongiform virus encephalopathy with marked neuronal destruction in the cerebral cortex and subcortical grey structures. The neuronal loss resulted in cerebral atrophy and hydrocephalus ex vacuo.

Phosphodiesterase inhibitors and cerebral vasospasm

Experimental cerebral vasospasm was studied in cat and monkey models. In the cat, the basilar artery was exposed by a transclival approach and spasm induced by the application of blood to the vessel. In the monkey, spasm was produced by injecting blood into the subarachnoid space. Vessel size was determined in the cat by direct observation and, in the monkey, by cerebral angiography. Several agents known to alter the synthsis and degradation of cyclic adenosine monophosphate (AMP) were used to modity the vasospasm produced. Isoproterenol (Norisodrine) and aminophyline were effective in reversing cerebral vasospasm when applied topically and when administered parenterally. It is suggested that manipulation of the cyclic AMP pathways may be an effective method of controlling cerebral vasospasm.

Experimental cerebral vasospasm and cyclic adenosine monophosphate (c-AMP)

Blood induced acute and chronic cerebral vasospasm were studied in Rhesus monkeys by serial angiography. Two vasoactive agents were evaluated. In acute spasm, phosphodiesterase inhibition by Aminophylline consistently reversed the vasospasm. This agent alone was ineffective in chronic spasm and required the addition of Isoproterenol to produce reversal of vasospasm. It is proposed that cerebral vasospasm may be associated with a decrease of intracellular c-AMP in vascular smooth muscle which can be reversed by manipulation of the enzyme pathway involved. It is further proposed that c-AMP is a basic common pathway through which adrenergic vascular reactivities are mediated.

Inhibition of the sympathetic nervous system by 5,6-dihydroxy-2-dimethylamino tetralin (M-7), apomorphine and dopamine

M-7, in doses of 1 mug/kg, reduces the resting heart rate of anesthetized dogs and cats. In similar dose ranges, M-7 blocks reflex activation of the sympathetic nervous system. Experimental procedures included bilateral carotid occlusion in the dog and central stimulation of vagi and right sciatic nerves in the cat. M-7 inhibits the response to postganglionic stimulation of the right cardioaccelerator nerve if the frequency of stimulation is 2 Hz; no inhibition is observed with a frequency of 18Hz. The inhibitory action of M-7 is antagonized by haloperidol, 50 mug/kg, or chlorpromazine, 150 mug/kg. Similar inhibitory actions and frequency specificity were observed in vitro using the right atrium of the cat and nerve stimulation. In cats, nerve stimulation was inhibited by apomorphine. Dopamine, in the presence of cocaine, also inhibited low-frequency nerve stimulation. It is postulated that prejunctional sympathetic nerves innervating the heart have dopamine receptors that serve as inhibitory role in transmission.

Specific movement of cell membranes fused with HVJ (Sendai virus)

When Ehrlich ascites tumor cells fused with UV-inactivated HVJ (Sendai virus) were cultured, the viral envelope antigens, which had been integrated at random into the cell membranes, accumulated at one site on the fused cell. The site showed a specific structure, namely, a projection of the cytoplasm from the spherical fused cell surface with clusters of many long microvillilike protrusions from it. When the fused cells were conjugated with antibody against Ehrlich ascites tumor cells and cultured, the antigen-antibody complex also accumulated on the projection.Associated with the development of the projection and accumulation of viral antigens, vacuoles developed at the base of the projection in the cytoplasm of the fused cells in culture. The development of the projection and vacuoles and the accumulation of viral antigens were all inhibited by glucose, mannose, galactose, sodium azide, and cycloheximide, and these inhibitions were reversible. All these structures were observed in multinucleated cells, but few in mononucleated cells after reaction with HVJ (Sendai virus). We consider that these three phenomena correlate with each other and may result from changes in cell-membrane systems caused by fusion of cells.

Electron microscope studies of heteroduplex DNA from a deletion mutant of bacteriophage phiX-174

A population of double-stranded replicative form of DNA molecules from bacteriophage varphiX-174 carrying a deletion of about 9% of the wild-type DNA has been discovered in a sample cultivated under conditions where the phage lysozyme gene is nonessential. The structures of deleted monomers, dimers, and trimers were studied by the electron microscope heteroduplex method. The dimers and trimers are head-to-tail repeats of the deleted monomers. Some interesting examples of the dynamical phenomenon of branch migration in vitro have been observed in heteroduplexes of deleted dimer and trimer strands with undeleted monomer viral strands from the wild-type phage.