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Pool boiling critical heat flux (CHF) measurements have been performed on stainless steel and zirconium wires in nanofluids consisting of oxide nanoparticles (7 to 250 nm) dispersed in water as well as in high-purity water after coating these wires with a variety of materials and methods. For the nanofluids study, nanoparticles of titania, alumina, zirconia, and yttria-stabilized zirconia (YSZ) were investigated for various sizes and concentrations. Results showed improvements in CHF in the range of 50% to 100%, with titania and zirconia exhibiting the highest and the lowest levels of improvement, respectively. Wires were coated separately with the same oxide nanoparticle materials, as well as pure titanium nanoparticles, using the electrophoretic deposition (EPD) technique and by nanofluid boiling. EPD coatings yielded superior and more consistent improvements in CHF values in clean water, suggesting that this could be a more practical approach than using nanofluids. Coating uniformity plays an important role in dictating the levels of CHF enhancement. In all cases, titania provided for high levels of improvement, while YSZ showed similarly high levels of improvement in some cases. Pure titanium coatings exhibited lower levels of improvement, indicating qualitatively that the lower wettability on metallic substrates (as compared to oxides) may play a role in dictating CHF improvements. Titanium, however, exhibits better adhesion to metallic substrates than do oxides, which is an important property for applications in a reactor environment. Given this, the improvements in CHF achieved by titanium coatings were sufficient to justify further study.

Parathyroid hormone (PTH) increased intracellular cyclic AMP and reduces Na+/phosphate cotransport activity in OK cells [Malmström & Murer (1986) Am. J. Physiol. 251, C23-C31; Caverzasio, Rizzoli & Bonjour (1986) J. Biol. Chem. 261, 3233-3237]. It was also shown that PTH activates phosphoinositide metabolism in OK cells [Hruska, Moskowitz, Esprit, Civitelli, Westbrook & Huskey (1987) J. Clin. Invest. 79, 230-239]. In the present paper we show that tumour-promoting phorbol esters are effective in reducing Na+/phosphate cotransport. The Ca2+ ionophores A23187 and ionomycin had only a small effect on Na+/phosphate cotransport; added together, A23187 and phorbol esters showed a synergistic action. Phorbol esters and phorbol esters plus ionomycin stimulated prostaglandin synthesis as well as cyclic AMP production; acetylsalicylic acid prevented phorbol-ester-induced prostaglandin synthesis and cyclic AMP production, but had no effect on inhibition of Na+/phosphate cotransport. In suspensions of OK cells, PTH and thrombin produced a rise in intracellular Ca2+. In contrast with PTH, thrombin did not elevate cellular cyclic AMP in suspended OK cells. PTH and thrombin reduced Na+/phosphate cotransport in suspended OK cells. It is suggested that two regulatory cascades are involved in PTH action on Na+/phosphate cotransport: cyclic AMP/kinase A and Ca2+/diacylglycerol/kinase C.

A technique is described and tested for mapping the sensitivities and preferred directions of motion at different locations within the receptive fields of direction-selective motion-detecting visual neurons. The procedure is to record the responses to a number of visual stimuli, each stimulus presentation consisting of a set of short, randomly-oriented, moving bars arranged in a square grid. Each bar moves perpendicularly to its long axis. The vector describing the sensitivity and preferred direction of motion at each grid location is obtained as a sum of the unit vectors defining the directions of motion of the bars in each of the stimuli at that location, weighted by the strengths of the corresponding responses. The resulting vector field specifies the optimum flow field for the neuron. The advantage of this technique over the conventional approach of probing the receptive field sequentially at each grid location is that the parallel nature of the stimulus is sensitive to nonlinear interactions (such as shunting inhibition for mutual facilitation) between different regions of the visual field. The technique is used to determine accurately the motion receptive fields of direction-selective motion detecting neurons in the optic lobes of insects. It is potentially applicable to motion-sensitive neurons with highly structured receptive fields, such as those in the optic tectum of the pigeon or in area MST of the monkey.

Abstract.: In a previous report we documented an increased Na+-dependent transport of inorganic phosphate (P i ) in Xenopus laevis oocytes injected with mRNA isolated from rabbit duodenum (Yagci et al., Pfluegers Arch. 422:211–216, 1992; ref 24). In the present study we have used expression cloning in oocytes to search for the cDNA/mRNA involved in this effect. The identified cDNA (provisionally named PiUS; for P i -uptake stimulator) lead to a 3-4-fold stimulation of Na+-dependent P i -uptake (10ng cRNA injected, 3–5 days of expression). Na+-independent uptake of P i was also affected but transport of sulphate and l-arginine (in the presence or absence of sodium) remained unchanged. The apparent K m -values for the induced Na+-dependent uptake were 0.26 ± 0.04 mm for P i and 14.8 ± 3.0 mm for Na+. The 1796 bp cDNA codes for a protein of 425 amino acids. Hydropathy analysis suggests a lack of transmembrane segments. In vitro translation resulted in a protein of 60 kDa and provided no evidence of glycosylation. In Northern blots a mRNA of ∼2 kb was recognized in various tissues including different intestinal segments, kidney cortex, kidney medulla, liver and heart. Homology searches showed no similarity to proteins involved in membrane transport and its control. In conclusion, we have cloned from a rabbit small intestinal cDNA library a novel cDNA encoding a protein stimulating P i -uptake into Xenopus laevis oocytes, but which is not a P i -transporter itself.

The interaction between the moth, Cactoblastis cactorum, and the cactus, Opuntia stricta, is used as a model to examine the question of whether the CO2 sense of a herbivorous insect can detect the CO2 gradients associated with a plant's metabolic activity. Both the anatomical and the electrophysiological characteristics of CO2-sensitive receptor neurons in C. cactorum indicate an adaptation to the detection of small fluctuations around the atmospheric background. Evidence is provided that further rises in background will impair the function of the sensory organ. In the habitat of the plant, during the diurnal window of the moth's activity, two types of CO2 gradients occur that are detectable by the moth's sensors. The first gradient, associated with soil respiration, is vertical and extends from the soil surface to an altitude of approximately 1 m. Its magnitude is well above the detectability limit of the sensors. The notion that this gradient provides, to a flying insect, a cue for the maintenance of a flight altitude favourable for host detection is supported by field observations of behaviour. The second gradient, associated with CO2 fixation by the plant, extends from the surfaces of photosynthetic organs (cladodes) over a boundary layer distance of approximately 5 mm. Again, its magnitude is well above the detectability limit. The notion that this gradient provides, to a walking insect, a cue to the physiological condition of the plant is supported by the observation that females of C. cactorum, prior to oviposition, actively probe the plant surface with their CO2 sensors. In a simulation of probing, pronounced responses of the sensors to the CO2-fixing capacity of O. stricta are observed. We propose that by probing the boundary layer, females of C. cactorum can detect the healthiest, most active O. stricta cladodes, accounting for earlier observations that the most vigorous plants attract the greatest density of egg sticks.

Summary: Brush border membranes were isolated from rat renal cortex by a divalent cation precipitation method.l-35S-cysteine uptake into the vesicles was measured by a rapid filtration method. Only minimal binding of the amino acid to the vesicles was observed. Sodium stimulatesl-cysteine uptake specifically. Anion replacement experiments, experiments in the presence of potassium/valinomycin-induced diffusion potential as well as experiments with a potential-sensitive fluorescent dye document an electrogenic sodium-dependent uptake mechanism forl-cysteine. Tracer replacement experiments as well as the fluorescence experiments indicate a preferential transport ofl-cysteine. Transport ofl-cysteine is inhibited byl-alanine andl-phenylalanine but not byl-glutamic acid and thel-basic amino acids. Initial, linear influx kinetics provide evidence for the existence of two transport sites. The results suggest (a) sodium-dependent mechanism(s) forl-cysteine shared by other neutral amino acids.

At twenty-three 20–30-year-old normal-hearing subjects the characteristic curves of amplitudes and latencies of the five early potentials, appearing within the first 8 ms after stimulus onset, were obtained. The potentials were registered with the earlobe-vertex pick-up, as described by Sohmer and with click stimulus rates of 5/sec, 10/sec, 50/sec and 100/sec. It could be seen: All five potentials depend in amplitude and latency on intensity; all potentials show with increasing click rate an adaptation and a delayed latency, when increasing the click rate from 10/sec to 50/sec; the adaptation phenomenon of the 1st, 2nd, 3rd and 5th potential is the most prominent, the 4th potential shows the smallest adaptation effect; the characteristic curve at 10/sec of the 1st and 3rd potential demonstrates a break at 70 dB SPL; the latencies of the five potentials begin to increase at click rates higher than 10/sec; the 4th potential seems to be the most suitable one for measuring the acoustical threshold; only the fifth potential diminishes in amplitude and increases in latency after administration of an anaesthetic, but an additional relaxant does not alter it any more.

A fraction of Ginkgo biloba, used in experiments with animals ensured significantly the diminution of sound damages caused by white noise or by a pure tone of 4.5 kHz. Higher amplitudes of the acoustic nerve potentials show the protective effect of this fraction of Ginkgo biloba at acute sound damages. It is moreover possible to hold physiologically the adaptation of excitation of the hair cells of the organ of Corti by the fraction of Ginkgo biloba before and after sound damage caused by white noise or during a pure tone of 4.5 kHz. The influence of the fraction of Ginkgo biloba can be seen by a significantly slower recovery of the noise damaged evoked potentials of the acoustic cortex. An efferent protective influence on the neurons of the acoustic cortex is discussed. The fraction of Ginkgo biloba in this form of solution has not been tested for clinical use but it seems to be rich in meaning.

11 Guinea pigs had a 50% streptomycin-sulfate solution injected into the middle ear. Complete loss of function of the peripheral vestibular organ occurred after two days, as was detectable by means of the caloric test. The high-degree decrease of the microphonic-potentials and the compound action potential was significant.

Injection of rat kidney cortex mRNA into Xenopus laevis oocytes leads to a stimulation of Na(+)-dependent SO4(2-) uptake. Based on this information, we have isolated from a corresponding library a cDNA (NaSi-1) that is most likely related to a Na+/SO4(2-) cotransport system. NaSi-1 cRNA leads in a time- and dose-dependent manner to specific stimulation of Na(+)-dependent SO4(2-) uptake in oocytes. The apparent affinity constants of the NaSi-1 cRNA-expressed transport resemble those of Na+/SO4(2-) cotransport in brush-border membrane. The NaSi-1 cDNA contains 2239 bp [including a poly(A) tail] and encodes a protein of 595 amino acids (66.05 kDa); the hydropathy profile suggests at least eight membrane-spanning regions. In vitro translation of NaSi-1 cRNA results in a protein of the expected size and suggests glycosylation. Northern blot analysis shows signals of 2.3 and 2.9 kb in kidney (more abundant in cortex than in papilla/medulla) and in mucosa of small intestine of rats. The above data indicate that we have structurally identified a membrane protein involved in renal and small-intestinal brush-border membrane Na+/SO4(2-) cotransport.

l-3H-lysine uptake into brush border membrane vesicles was measured by a rapid filtration technique. A significant binding ofl-lysine at the vesicle interior was observed. Extrapolating initial linear uptake to zero incubation time did not indicate binding of the amino acid to the external membrane surface.

Abstract: Brush border membranes were isolated from rat renal cortex by a divalent cation precipitation method.l-35S-cystine uptake into the vesicles was measured by a rapid filtration method. Covalent incorporation of tracer into membrane proteins was observed after prolonged incubations. At short incubation periods (1 min) binding was small and allowed an analysis of transmembrane transport. To guarantee transport ofl-cystine, the experiments were performed in the presence of the oxidant diamide.Sodium stimulatedl-cystine uptake specifically. A potassium/valinomycin induced inside negative diffusion potential stimulated sodium dependentl-cystine transport. Thus, transport is potential sensitive in the presence of sodium. At low substrate and inhibitor concentrations,l-cystine transport was inhibited byl-lysine,l-ornithine andl-arginine but not byd-lysine in the presence and absence of sodium. At higher inhibitor concentration, the neutral amino acidsl-phenylalanine andl-leucine also inhibitedl-cystine uptake, but only the sodium dependent uptake. These inhibition experiments suggest thatl-cystine is transported by the brush border membrane by a transport system for basic amino acids not necessarily requiring sodium. In addition, transport ofl-cystine can also procee via sodium dependent transport pathways for neutral amino acids.In the concentration range tested (up to 0.225 mmoles/l), no saturation ofl-cystine transport was observed in the presence and absence of sodium.

Poly(A)+ mRNA was isolated from rabbit kidney cortex and injected into Xenopus laevis oocytes. Injection of mRNA resulted in a time- and dose-dependent increase in Na(+)-independent uptake of L-[3H]alanine and L-[3H]arginine. L-Alanine uptake was stimulated about 3-fold and L-arginine uptake was stimulated about 8-fold after injection of mRNA (25-50 ng, after 3-6 days) as compared with water-injected oocytes. T.I.C. of oocyte extracts suggested that the increased uptake actually represented an increase in the oocyte content of labelled L-alanine and L-arginine. The expressed L-alanine uptake, obtained by subtracting the uptake in water-injected oocytes from that in mRNA-injected oocytes, showed saturability and was inhibited completely by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH) and L-arginine. The expressed L-arginine uptake in mRNA-injected oocytes also showed saturability, being completely inhibited by L-dibasic amino acids) and partially inhibited by BCH. Expression of both L-alanine and L-arginine uptake showed clear cis-inhibition by cationic (e.g. L-arginine) and neutral (e.g. L-leucine) amino acids. In all, this points to the expression of a Na(+)-independent transport system with broad specificity (i.e. b degree, (+)-like). In addition, part of the expressed uptake of L-arginine could be due to a system y(+)-like transporter. After size fractionation through a sucrose density gradient, the mRNA species encoding these increased transport activities (Na(+)-independent transport of L-alanine and of L-arginine) were found in fractions of an average mRNA chain-length of 1.8-2.4 kb. On the basis of these results, we conclude that Na(+)-independent transport system(s) for L-alanine and L-arginine from rabbit renal cortical tissues, most likely proximal tubules, are expressed in Xenopus laevis oocytes. These observations may represent the first steps towards expression and cloning of these transport pathways.

The effects of intravesicular NAD on Na+-dependent32Pi uptake were investigated in isolated rat kidney brush border membrane vesicles (BBMV). NAD was introduced into the vesicles by osmotic shock, and extravesicular NAD was removed by passing the vesicles through a anion exchange column. The effectiveness of the osmotic shock procedure and the hydrolysis of extra- and intravesicular NAD were controlled by enzymatic analysis and thin layer chromatography. ADP-ribosylation of the membrane proteins was analyzed in vesicles osmotically shocked in the presence of either [adenylate-32P]-NAD or [adenine-2,8-3H]-NAD by SDS-polyacrylamide gel electrophoresis.

We have isolated a cDNA clone by screening a rabbit kidney cortex cDNA library for expression of sodium-independent transport of L-arginine and L-alanine in Xenopus laevis oocytes. Expressed uptake relates to a single component of sodium-independent transport for dibasic and neutral amino acids. This transport activity resembles the functionally defined system b0,+ and carries cystine and dibasic amino acids with high affinity. The rBAT (b0,+ amino acid transporter-related) mRNA is found mainly in kidney and intestinal mucosa. It encodes a predicted 77.8-kDa protein with only one putative transmembrane domain and seven potential N-glycosylation sites. This protein could either be a constitutive element or a specific activator of system b0,+.

On the basis of experiences made during the last 9 years with more than 200 hearing impaired children and adults by means of supraliminal ERA the various possibilities and sources of error could be demonstrated for the registrations of the acoustically evoked potentials. The importance of the three-channel synchronous registration technic is explained. The relative standard deviation is proved and amounts to 18–25% near threshold and to 7–10% by the use of middle intensities of the sound pressure level. New area calculations (PDP 12) of the acoustic biopotentials give favourable results. This method proved to a high degree reliable in the supraliminal range as we could demonstrate in patients suffering from otosclerosis registered before and after stapedectomy. The supraliminal ERA-diagnosis covers hearing impairment such as loss of adaptation, diminution of dynamics in the supraliminal range, recruitment, and hyperacusis. Accordingly the typical pathophysiological ERA-characteristic curve for amplitudes and latencies could be found in more than 100 hard-of-hearing children.

The activity of single motor units of the splenius-capitis muscle of healthy human subjects and patients with unilateral vestibular lesions was recorded by means of microelectrodes. The major part of these units reacted to vestibular stimulation in the same way as primary and secondary vestibular neurones of other vertebrates. The reactions of these units to trapezoidale stimuli is identical to that of vestibular neurones.

In a former investigation the effect of promethazine (Atosil®) on the late acoustically evoked potential component N1 was examined. Now the cochlear and the brain-stem potentials were registered by the earlobe-vertex pick-up with i.m. application of 0.8 mg/kg (body weight) promethazine. There was no influence of promethazine either on the compound action potential (NAP) or on the brain-stem potentials (Pot. II–V), but sedation improves significantly the signal-to-noise ratio, therefore we sedate all patients when registering the five early acoustically evoked potentials.

62 Meerschweinchen wurden zweimal 40 Mi-nuten mit einem Breitbandrauschen von 20-20 000 Hz, 105 dB SPL beschallt. Zwischen beiden Schallbelastungen lag eine Pause von 24 Stunden. Abgeleitet wurden die CM, die NAP und SEP. Der Schädigungsgrad der akustischen Biopotentiale nach zweimaliger Beschallung war unterschiedlich. Während die CM nur wenig betroffen waren, zeigten die NAP eine deutliche Beeinträchtigung der Erregung und Adaptation und die SEP eine Einschränkung vor allem der Erregung. Daraus ist zu schlie-ßen, daß die CM allein nicht als Kriterium für eine Schädigung des akustischen Systems durch Schalltrau-mata ausreichen. Weiter ergibt sich, daß dieses System in der Lage ist, kurzfristig periphere Schäden zentral auszugleichen und daß eine erneute Belastung nicht zwangsläufig zu einer Addition oder Kumulation der SchäUdigung führen muß.

We have isolated two cDNA clones, NaPi-2 and NaPi-3, by screening rat kidney cortex and human kidney cortex cDNA libraries, respectively, for expression of sodium-dependent phosphate transport in Xenopus laevis oocytes. Substrate specificity and a detailed kinetic analysis (Na, Pi, H+ concentrations) suggested that expressed uptake activities relate to proximal tubular brush border membrane Na/Pi cotransport. NaPi-2 cDNA contains 2464 bp encoding a protein of 637 aa; NaPi-3 cDNA contains 2573 bp encoding a protein of 639 aa. NaPi-2- and NaPi-3-deduced protein sequences show high homology to each other but are different from the protein sequence deduced from the previously cloned NaPi-1 cDNA (from rabbit proximal tubules). Hydropathy profile predictions suggest at least eight membrane-spanning regions in NaPi-2/3-related proteins. In vitro translation results in proteins of the expected size and suggests glycosylation. Northern blot analysis shows corresponding mRNA species (approximately 2.7 kb) in kidney cortex of various species but no hybridization with RNAs isolated from a variety of other tissues (including intestinal segments); a hybridization signal (approximately 4.8 kb) was observed only in the lung (human). We conclude that we have structurally identified two closely related proteins most likely involved in human and rat renal brush border Na/Pi cotransport.

Homolateral efferent influence: An isolated, histologically verified damage of the nucleus cochlearis (degeneration of the ganglion cells) of guinea pigs, quantitatively dependent on an increased dose of Gentamicinsulfate, causes — if effected by ipsilateral acoustic stimulation — a significant diminution of the “slow evoked potentials” of the acoustic cortex and an increase of the “compound action potentials” of the acoustic nerve. By giving higher doses of Gentamicinsulfate, histologically a greater damage to the central auditory pathways and only a little damage of the hair cells of the organ of Corti was to be found and thereby we registered greater diminution of the “slow evoked potentials” of the acoustic cortex and little decrease of the “cochlear microphonics”, but further increase of the “compound action potentials” of the acoustic nerve. The loss of inhibition of the central auditory pathways of the cochlea only influenced the “compound action potentials” of the acoustic nerve, but not the “cochlear microphonics.”Interesting for the clinical therapy is the unimportant ototoxic effect of Gentamicinsulfate in comparison with the therapeutic dose of Streptomycinsulfate.Contralateral efferent influence: The measurement with platinum wire-electrodes (0,2 mm Ø) on the cochlear nerve of de-afferented guinea pigs (the cochlea being removed) demonstrated four new acoustic biopotentials by contralateral acoustic stimulation on the other ear. The amplitudes (60—70 μV, 105 dB SPL contralateral acoustic stimulation) of those “compound efferent action potentials” (latency of 2,3 msec, 3,1 msec, 4,7 msec, 32 msec) depend on the intensity of contralateral acoustic stimulation.The semi-dissection of the pons effected a diminution, the complete dissection of the pons a loss of those by contralateral adequate stimulation evoked acoustic biopotentials. Measurements on the nucleus cochlearis dorsalis of the de-afferented side of the acoustic system indicated an increase of the amplitudes (95—140 μV, 105 dB SPL) of the compound efferent action potentials.ResumeInfluence homolaterale efferente: Les experiences ont demontre qu'une lesion elective du nucleus cochlearis (degenerescence des cellules ganglionnaires) du cobaye, qu'on pouvait verifier histologiquement et qui dependait quantitativement d'un dosage augmente de Gentamycin-sulfate, causait — effectuee par stimulation acoustique ipsilaterale — une diminution significative des ←potentiels lentement evoques→(←slow evoked potentials→) du cortex acoustique, et une augmentation des ←potentiels d'action composee→(←compound action potentials→) du nerf acoustique. En augmentant le dosage du Gentamycin-sulfate, un plus grand dommage des voies auditives centrales, au point de vue histologique, en resultait; tandis que les lesions des cellules auditives et de l'organe de Corti etaient amoindries.En ce cas, nous observions une reduction plus significative des ←potentiels lentement evoquees→(←slow evoked potentials→) du cortex acoustique, et une diminution peu considerable des ←microphoniques cochleaires→(←ochlear microphonics→), mais une augmentation plus etendue des ←potentiels d'action composee→(←compound action potentials→) du nerf auditif. La perte d'inhibition des voies auditives centrales a l'egard de la cochlee n'influence que les ←potentiels d'action composee→(←compound action potentials→) du nerf acoustique, sans lesions des ←microphoniques cochleaires→(←cochlear micro-phonics→).Au point de vue d'une therapie clinique, des consequences interessantes resultent de l'effet ototoxique bien insignifiant du Gentamycin-sulfate en comparaison du dosage therapeutique du Streptomycin-sulfate.Influence controlaterale efferente: Les mesures du nerf cochleaire des cobayes (de-afferents) — la cochlee etant enlevee — au moyen d'electrodes de fil-platinum (0,2 mm Ø) demontraient quatres nouveaux ←bio-potentiels acoustiques→, causes par une stimulation acoustique controlaterale de l'autre oreille. Les amplitudes (60-70 μV, 105 dB SPL stimulation acoustique controlaterale) de ces ←potentiels d'action composee efferents→(←compound efferent action potentials→) — d'une latence de 2,3 msec, 3,1 msec, 4,7 msec, 32 msec — dependent de l'intensite acoustique controlaterale.La semi-dissection du pont donnait une diminution, la dissection totale une perte de ces ←bio-potentiels acoustiques→, evoques par une stimulation controlaterale adequate. Des mesures au niveau du nucleus cochlearis dorsalis du cote deafferent du systeme acoustique presentaient un accroissement des amplitudes (95-140 μV, 105 dB SPL) des ←potentiels d'action composee efferents→(←compound efferent action potentials→).

THOUGH many new antibiotics have been found, the streptomycin series have not lost their importance. They are still one of the most effective remedies for all forms of tuberculosis. However, the use of streptomycin is limited by its additional neurotoxical and ototoxical affects. Such accompaniments were first described by Brown and Hinshaw.1 Since then, a great many clinical and experimental papers concerning the ototoxicity of basic streptomyces-antibiotics have been published.2-9Electrophysiological experiments of Stange et al9 concerning the efficiency of streptomycin-sulfate on excitation and adaptation of the hair-cells in the organ of Corti, especially, proved that streptomycin injures the metabolism of the sensory cells in the ear. It affects the cellular membrane and restricts its reabsorption.5 The result is an accumulation of streptomycin in the sensory cells and, consequently, loss of function.Experiments to reduce the ototoxic effect of streptomycin have been made for several years.

Zusammenfassung Das Auftreten toxischer Schäden am akustischen System — zentral wie peripher —, durch Streptomycinsulfat in 20facher therapeutischer Dosis verursacht, kann im Tierexperiment durch Lösung des Streptomycins in Ozothin weitgehend gemindert und bei vorheriger i. m. Injektion von Ozothin sogar verhütet werden. Bei dem wesentlich ototoxischeren Neomycinsulfat kann durch Ozothin eine weitgehende, signifikante Minderung der ototoxischen Wirkung erreicht werden. Die „in vivo-Versuche” an mit drei Infektionsarten infizierten Mäusen beweisen, daß das Ozothin im Vergleich zum Aqua bidest. die biologische Aktivität des Streptomycinsulfats weder abschwächt, noch verstärkt, also nicht beeinflußt. Somit zeigen these Untersuchungsergebnisse eindeutig, daß in der Klinik bei einer notwendigen Behandlung mit basischen Streptomyces-Antibiotica die Zugabe von Ozothin eine Verhütung ototoxischer Schäden ermöglichen und sogar eine Erhöhung der Streptomycindosen — unter strenger audiologischer Kontrolle — wahrscheinlich werden lassen kann.

Zusammenfassung: In den Jahren 1964 bis 1968 wurden in der Universittsklinik fr Hals-, Nasen- und Ohrenkrankheiten in Freiburg 78 Patienten mit pltzlicher Hrverminderung oder- verlusten ber 4–6 Wochen stationr behandelt. Der Behandlungsbeginn lag bei 41 Kranken innerhalb der ersten 6 Wochen (Gruppe a), bei 37 Patienten zwischen 6–24 Monaten nach Eintritt des akuten Krankheitsgeschehens (Gruppe b). Die Kranken erhielten tglich Complamin, Ozothin, Neurobion, Rovigon und jeden 2. Tag im Wechsel 7% ige NaHCO3-infusionen und Stellatumblockaden. Der Behandlungserfolg in beiden Gruppen ist signifikant unterschiedlich (3 σ). Die Gruppe a wies in den tiefen Frequenzen einen Behandlungserfolg von 15 dB, in den mittleren und hohen Frequenzen von durchschnittlich 20 dB, die Gruppe b 3–4 dB in den tiefen Frequenzen, 4–5 dB in den mittleren Frequenzen und 5–7 dB in den hohen Frequenzen auf nach 4–6 Wochen Behandlungsdauer. Bei einer weiteren Gruppe von Patienten, die zustzlich Gleichgewichtsstrungen hatten, war der Hrgewinn von den Frherfaten und Spterfaten ohne Gleichgewichtsstrungen unterschiedlich; im mittleren Frequenzbereich von 1–2 kHz zeigten auch diese Patienten den gleichen Hrgewinn von 20 dB am Ende der stationren Behandlung, konnten jedoch in tiefen Frequenzen von 0.06–0,5 kHz und in den hohen Frequenzen von 3,0–12,0 kHz durchschnittlich nur einen Hrgewinn von 8 dB am Ende der stationren Behandlung erreichen. — Bei 8 Patienten von 78 Erkrankungen konnte kein eindeutiger therapeutischer Erfolg erzielt werden, von denen 1 Patient der Gruppe a und 7 Patienten der Gruppe b angehrten. Das Behandlungsergebnis beweist die Notwendigkeit eines sofortigen Therapiebeginns nach Eintritt des akuten Hrsturzes. Eine lange Behandlungsdauer ist nicht nur berechtigt, sondern auch notwendig. Selbst bei Patienten, bei denen rasch ein normales Gehr innerhalb der ersten 2 Wochen nach Behandlungsbeginn erreicht werden konnte, ist noch eine weitere stationre Behandlung von etwa 10 Tagen notwendig, um Rezidive zu vermeiden. Im Durchschnitt setzt nach der 3. und in den hohen Frequenzen auch nach der 4. Wochen noch ein deutlicher, teils signifikanter Hrgewinn ein. So ist in den hohen Frequenzen bei den Patienten der Gruppe b erst in der 4. Woche berhaupt ein deutlicher Hrgewinn zu verzeichnen. Das Ergebnis hat weiterhin gezeigt, da die Patienten, bei denen gleichzeitig Gleichgewichtssymptome vorhanden sind, vor allem im mittleren Frequenzbereich von 1–2 kHz ein sehr guter Hrgewinn durch die Therapie ermglicht werden kann, whrend die hohen und tiefen Frequenzen einen mittleren Hrgewinn nur von 7 dB verzeichnen. Es hat sich also eindeutig ergeben, da bei Patienten ohne Strungen des Gleichgewichtsapparates der therapeutische Erfolg hinsichtlich des gesamten Frequenzbereiches wesentlich gnstiger ist. Bei Kontrollen bis 6 Monaten nach Therapiebeginn zeigt sich, da keine Rezidive zu verzeichnen sind, sondern noch Besserungen bis zu einem Hrgewinn von 30 dB vor allem bei der Gruppe a eintreten. — Ein vollstndiges Literaturverzeichnis bis zum Jahre 1965 befindet sich beiNeveling.

Zusammenfassung:

50%-DMSO-solution effects the following damage to the acoustic biopotentials (cochlear microphonics; excitation and adaptation of the compound action potentials of the acoustic nerve) of the cat:1.After application of DMSO into the external auditory meatus during 21 days:a)diminution of the threshold shift of 20 dB;b)severe damage to the outer hair cells of 65%;c)medium damage to the inner hair cells of 30%;d)disturbance of the metabolism of adaptation;e)severe damage to the hair cells of the basal turn of the cochlea.2.Acute 500/0-DMSO-damage:a)application into the external auditory meatus effects a damage to the compound action potentials of the acoustic nerve of 40% (during 6 hours);b)application into the middle-ear effects a damage to the compound action potentials of the acoustic nerve of 60% (during 6 hours).

After removal of the organ of Corti on one side, four sequential efferent compound action potentials were registered from the cochlear nerve of the same side upon click stimulation of the contralateral ear. For an input of 105 dB SPL, there were three early potentials having maximum average latencies of 2.3, 3.1, and 4.7 msec, and average amplitude of 60, 50, and 25 µV respectively.

In the present paper the input-output functions of the slow acoustically evoked potential are determined under the following conditions: vertex-, ipsi-lateral and contra-lateral pick-up. In all three modes of pick-up we got the input-output function of the high stimulus repetition rate;—this means: for the adapted stage of the system as well as that for the small repetition rate, the non-adapted stage. In all three modes of pick-up we found a different input-output-function and a difference between the adapted and the non-adapted stage. The simultaneous registration is more advisable than the successive one. We determined the normal characteristic curves of 10 adults in order to compare them with patients. The vertex-pick-up seems to be the best one for determining the threshold, whereas the contralateral pick-up seems to give more information about the pathological function of the acoustic system.

The method described in this paper enables the locomotor activity of small insects to be recorded. It is based on variations in capacitance within a bridge circuit, the variations being due to movements of the animals. The method is adapted to the use of multi-channel action recorders, thus allowing a greater number of sensor units to be employed simultaneously.

1. An Katzen, bei denen in Dial-Narkose das runde Fenster freigelegt worden war, wurde bei monauraler Beschallung in einer reflexionsfreien, elektrisch abgeschirmten Kammer mit Hilfe der Makroelektrodenrechnik am runden Fenster Reizfolgeströme und Summenaktionspotentiale abgeleitet.

The average of central acoustic responses of awake human beings according to the EEG for purposes of ‘objective audiometry’ shows, if accurately, only a very small dispersion-range of these responses in normal hearing persons. Possibilities of error of the computer-methods are represented in detail. Thus it is scientifically proven that significant differences in audiograms of deaf persons, done with the computer, compared with normal hearing people, can be registered objectively. By using the “power functions” (according to Stevens subjectively) hearing-threshold, adaptation, perception of soundvolume and recruitment in cases of impaired hearing can be verified objectively and then quantitatively judged. The results and the problems of childrens are represented.

Zusammenfassung 1.Am runden Fenster von Meerschweinchen in Nembutal-Narkose wurden bei monauraler Beschallung mit Rechteckimpulsen verschiedener Folgefrequenzen, die in dB-Stufen abgeschwächt wurden, in einer reflexionsarmen, elektrisch abgeschirmten Kammer mit Hilfe von Makroelektroden Adaptationszeitgänge der Summenaktionspotentiale abgeleitet.2.An unbehandelten und vorbehandelten (nach Ephedrin 50 mg/kg; nach Beschallung 3000 Hz, 120 dB, 45 min Dauer; und nach der gleichen Sinustonbeschallung unter Ephedrinwirkung) Meerschweinchen wurden Adaptation-Zeit-Diagramme und Adaptationsfächer aufgestellt. Zum Erhalt der Adaptation-Zeit-Diagramme, bei denen in der Ordinate die Höhe der gemessenen Potentiale, in der Abszisse die Zeit nach Ende einer entsprechenden Vorbehandlung eingetragen ist, wurde unmittelbar nach der Vorbehandlung der Tiere aller 2 min ein Adaptationszeitgang bei einer Reizfolgefrequenz von Rechteckimpulsen von 100/sec registriert, wobei jeweils der dynamische Wert und ein Mittelwert der statischen Werte dieses Adaptationszeitganges in das Diagramm eingetragen wurde. Das Ergebnis erlaubte dann die Registrierungen der vonKeidel angegebenen Adaptationsf⇂her, bei denen in der Ordinate ebenfalls die Höhe der gemessenen Potentiale und in der Abszisse die Abschwächung der Schallstärke in dB aufgetragen sind, wobei die verschiedenen Reizfolgefrequenzen als Parameter dienen.3.Hiermit konnten Aussagen Über das Adaptationsverhalten der Sinneszellen des Cortischen Organs gemacht werden. Ein Einfluß von Ephedrin auf die Erregungsadaptation konnte wahrscheinlich gemacht werden. Diese Wirkung wurde hierbei besonders deutlich dadurch, daß eine durch massive Sinustonbeschallung nachgewiesene funktionelle Störung der Sinneszellen einhergehend mit einer Verschlechterung der Hör- und Unterschiedsschwelle unter sympathicomimetischer Wirkung signifikant geringer ist als bei einer physiologischen Ausgangslage. Diese Ergebnisse weisen darauf hin, daß die Sinneszellen des Ohres bei gleichen akustischen Reizen je nach der sympathischen Erregung verschiedene Erregungs- und Adaptationszustände aufweisen können.

Demonstration of the correlation between morphological, electrophysiological and biochemical findings makes it possible to obtain a more comprehensive observation on the inner ear function:1.Functional impairment of the hair cells of the organ of Corti caused by ototoxic drugs was seen earlier than morphological changes.2.The S-shaped curve of the time course of adaptation of the compound action potentials of the acoustic nerve was morphologically confirmed to be a sum of integration of the two curves due to both kinds of sensory cells in the organ of Corti.3.The sensory cells with nuclear swelling are functionally inactive, and even those which show a morphologically normal appearance sometimes demonstrate functional impairment.4.Differentiation of the damages caused by acoustic stimulation and by ototoxic drugs is morphologically impossible; it is, however, electrophysiologically and immunophoretically possible by the time course of adaptation and also by a newly formed line of precipitate in the a-globulin region of the peri- and endolymph, respectively.