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Background: During the early part of the COVID-19 pandemic, the Canadian Society of Otolaryngology - Head & Neck Surgery (CSO-HNS) task force published recommendations on performance of tracheotomy. Since then, our understanding of the virus has evolved with ongoing intensive research efforts. New literature has helped us better understand various aspects including patient outcomes and health care worker (HCW) risks associated with tracheotomy during the COVID-19 pandemic. Accordingly, the task force has re-evaluated and revised some of the previous recommendations. Main body: Based on recent evidence, a negative reverse transcription polymerase chain reaction (RT-PCR) COVID-19 swab status is no longer the main deciding factor in the timing of tracheotomy. Instead, tracheotomy may be considered as soon as COVID-19 swab positive patients are greater than 20 days beyond initial symptoms and 2 weeks of mechanical ventilation. Furthermore, both open and percutaneous surgical techniques may be considered with both techniques showing similar safety and outcome profiles. Additional recommendations with discussion of current evidence are presented. Conclusion: These revised recommendations apply new evidence in optimizing patient and health care system outcomes as well as minimizing risks of COVID-19 transmission during aerosol-generating tracheotomy procedures. As previously noted, additional evidence may lead to further evolution of these and other similar recommendations. Graphical abstract:

Live load distribution factors have been used in bridge design for decades as a simple method with which to estimate live load effects. Live load distribution is important for the design of new bridges as well as for the evaluation of existing bridges. AASHTO's Standard Specifications for Highway Bridges and the AASHTO LRFD Bridge Design Specifications contain the most common methods in use for computing live load distribution factors. The load and resistance factor design (LRFD) equations were developed under NCHRP Project 12-26 and reflect the wide variation in modern bridge design. The limited ranges of applicability and complexity have been viewed as weaknesses of these equations since their adoption into the LRFD specifications. When bridges fall outside these ranges, the specifications mandate that a refined analysis be used. The design community would welcome a simple and reliable procedure for live load distribution. Research was done to develop simplified live load distribution factor equations for moment and shear to replace those in the current LRFD specifications. In the study, an automated process was used to compare live load distribution factors calculated by using several simplified methods to a grillage analysis. On the basis of the comparison, two methods were chosen for further investigation: Henry's method (an adjusted uniform distribution method) and the lever rule. The lever rule was simplified to an equation form, and calibration factors were added. Both methods are based on fundamental concepts and were shown to be simple and accurate. A combination of Henry's method and the calibrated lever rule is recommended. This method predicts both moment and shear distribution factors more accurately than the current LRFD equations, without the restrictions on ranges of applicability of the current LRFD equations. The methods outlined are limited to straight bridges.

Abstract:  Sediments of the Eckfeld maar (Eifel, Germany) bear a well-preserved Eocene fauna and flora. Biostratigraphically, Eckfeld corresponds to the Middle Eocene mammal reference level MP (Mammals Paleogene) 13 of the ELMA (European Land Mammal Age) Geiseltalian. In the maar crater, basalt fragments were drilled, representing explosion crater eruption products. By 40Ar/39Ar dating of the basalt, for the first time a direct numerical calibration mark for an Eocene European mammal locality has been established. The Eckfeld basalt inverse isochron date of 44.3±0.4 Ma suggests an age for the Geiseltalian/Robiacian boundary at 44 Ma and, together with the 1995 time scale of Berggren et al., a time span ranging from 49 to 44 Ma for the Geiseltalian and from 44 to 37 Ma for the Robiacian, respectively. Additional 40Ar/39Ar dating on a genetically related basalt occurrence close to the maar confirms a period of volcanism of ca. 0.6 m.y. in the Eckfeld area, matching the oldest Eocene volcanic activity of the Hocheifel volcanic field.

Bridge 1.351 on Business Route 896 in Glasgow, Delaware, was replaced with one of the first state-owned all-composite bridges in the nation. Composites are lightweight construction materials that do not corrode, which results in benefits such as ease of construction and reduced maintenance costs. A summary of the design, large-scale testing, fabrication, erection, and monitoring of this bridge is presented. The bridge was designed to AASHTO load and resistance factor design specifications. A methodology was developed to incorporate the engineering properties of these unique composite materials into the design. The bridge consists of two 13 × 32 ft (3.96 × 9.75 m) sections joined by a unique longitudinal joint. The sections have sandwich construction consisting of a core [28 in. (71.12 cm) deep] and facesheets [0.4 to 0.6 in. (10.16 to 15.24 mm) thick] that provide shear and flexural rigidity, respectively. The composite bridge was fabricated with E-glass preforms and vinyl-ester resin, which offers excellent structural performance and long-term durability. Each of the sections was fabricated to near-net shape in a single step by a vacuum-assisted resin transfer molding process. The overall structural behavior has been accurately predicted with simple design equations based on sandwich theory for anisotropic materials. Large-scale testing of full-sized subcomponents was conducted to prove that the design satisfied deflection, fatigue, and strength limit states. A redundant longitudinal joint was designed that consisted of both an adhesively bonded vertical joint between sections and splice plates. Assembly procedures were developed, and transverse testing of the full-sized joint was conducted. Final bridge sections were proof-tested to the strength limit state. The construction phase included section positioning, joint assembly, and application of a latex-modified concrete wear surface. The bridge was reopened to traffic on November 20, 1998. Results from the long-term monitoring effort will be documented.

Summary Since noting is known as yet of the acute action of saluretics on the renal excretion and clearance of stable inorganic iodine127 16 healthy young adults were examined after a single intravenous injection of 20 mg furosemide. Compared to the effect on the sodium excretion which increased to a maximum of 13.6 times the initial value the effect of furosemide on the excretion and clearance of iodide was slight and of short duration. In the first 30 minutes after the administration of furosemide the mean excretion of iodide increased highly significantly from 44±32 (S. D.) ng/min in the control period to 163±119 ng/min. In the 30 minutes following it decreased on an average to 109±66 ng/min and afterwards returned to the initial value. The iodide clearance behaved in a like manner. The excretion of inorganic iodine can be more closely correlated with the urine flow than with the excretion of sodium and it does not depend on the excretion rate and clearance of endogenous creatinine.

In the St. Andreasberg ore district, southwest Harz, at some time between the main and subsequent stages of mineralization sensu Wilke (1952), potassium feldspar (adularia) was formed hydrothermally. Based on isotopic dating (Rb/Sr, 40Ar/39Ar), the formation of this mineral is ascribed to the Early Cretaceous. Thus, part of the St. Andreasberg mineralization is proved to have been formed in the Late Mesozoic. The mineralization process forming feldspar does not coincide with magmatic phases of the area.

This report reexamines experimentally the problem of competitive indeterminacy in mixed-species populations of the flour beetles, Tribolium confusum and T. castaneum. Indeterminacy takes the form of alternative competitive outcomes: in some replicate cultures one species exterminates the other with a probability, say p, whereas in others, the opposing species wins with a complementary probability, 1-p. The conventional explanation for this is the genetic founder effect hypothesis--an explanation based on genetic stochasticity. The experiment reported here partitioned indeterminacy into founder effect and nonfounder effect components. The results implicate demographic stochasticity, not classical genetic founder effect, as a factor influencing the identity of the winning species.

Summary The effect of bezafibrate (200 mg t.i.d.) on renal and, to some degree, on muscular function was studied in nine patients with primary hyperlipoproteinemia. No signs of a reduction in creatinine excretion or an increase in muscular proteins could be found serving as a possible explanation for the slight increase in serum creatinine observed in a bezafibrate long-term study in more than 1,000 patients. Further studies are necessary for clarification.

Summary The renal excretion of manganese is investigated for different urine flow rates in adults of both sexes with normal and disturbed kidney function. Mn is determined by emission spectral analysis. During antidiuresis with a mean urine flow rate of 0,97 ± 0,66 ml/min (SD) the average excretion of Mn is 11,4 ± 19,4 ng/min for 1,73 m2 body surface area. With an indifferent urine flow (4,43 ± 2,11 ml/min) the average Mn excretion is 13,5 ± 19,3 ng/min. For this type of diuresis Mn excretion and urine flow rate are slightly positively correlated. A further increase in urinary excretion of Mn is observed during osmotic diuresis. In this case 160,6 ± 180,5 ng Mn/min are eliminated for an urine production of 22,2 ± 6,8 ml/min. The difference of the mean excretion values is highly significant (P < 0,001) between indifferent urine flow and osmotic diuresis, insignificant between antidiuresis and indifferent urine flow, and significant (P < 0,01) between antidiuresis and osmotic diuresis. Down to a clearance value for inulin of less than 30 ml/min and for PAH of less than 200 ml/min and 1,73 m2 body surface area, the Mn excretion is largely independent of the renal hemodynamics.

Summary The renal excretion of chromium was studied for different urine flows in normal and in renal diseased persons of both sexes. Chromium was determined by emission spectral analysis. During antidiuresis, in healthy persons and those with renal disease, but excluding patients with renal insufficiency, the average excretion of chromium was 1,504 ± 2,281 ng/Min. for a body surface area of 1,73 m2, with a urine flow (± standard deviation) of 1, 12 ± 0,83 ml/Min.. At an indifferent urine flow of 4,43 ± 2, 11 ml/Min. the average chromium excretion amounted to 2,255 ± 2,483 ng/Min.. In this range of urine flow there is a highly significant positive correlation between the renal excretion of chromium and the rate of urine flow. Chromium excretion was significantly increased during osmotic diuresis with hypertonic mannitol solution. It amounted to 15, 14 ± 20,41 ng/Min. at an average urine flow of 23,77 ± 7,38 ml for a body surface area of 1,73 m2. Similarly increased values for the excretion rate of chromium observed during water diureses. The wide variability of chromium excretion within individual experimental groups cannot be correlated with the different functional states of the kidney. Down to a clearance value for inulin of less than 30 ml/Min. and for p-aminohippurate of less than 200 ml/Min., related to 1,73 m2 of body surface area, the chromium excretion was largely independent of the renal hemodynamics.

Summary In 10 patients with hepatic cirrhosis of various etiology both the insorption and the volume of distribution of tritiated water are determined. Indicator for the velocity of insorption is the time interval between the oral application of 200 µCi THO distributed in 100 ml tap water and the appearance of a peak concentration of the isotope in the serum. In comparison with normal controls the insorption of THO is protracted in patients with hepatic cirrhosis from 37.0 ± 4.4 min (S.E.) to a mean of 69.0 ± 29.6 min. Individually the “insorption time” can be quite normal. The prolongation of the process of insorption is independent of the apparent volume of distribution of THO or of the etiology of hepatic cirrhosis. In the early phases of the insorption which are characterized by the main increase of the radioactivity in serum there is no difference between patients with hepatic cirrhosis and normal controls. Although an alteration of body fluid metabolism can not be excluded as a source of the prolonged equilibration, it is suggested that changes of the intestinal blood flow, of the tissue pressure and of the colloidosmotic pressure are due to a disturbance of the insorption of tritiated water in patients with hepatic cirrhosis.

An analysis was performed on a prehistoric human vertebral column recovered during an archaeological excavation in the Sierra of northern California. Fifteen burials believed to represent the Maidu culture of 400 to 700 years ago were recovered. The vertebral column from one of the individuals is particularly significant because of three embedded projectile points. The analysis attempts to recreate the trajectory of each point; to determine the possible extent of damage done by each with emphasis upon which could have been fatal; and by employing available ethnographic and archaeological data, to suggest the possible circumstances surrounding the violent event. The conclusion suggests that death may have resulted from any of the three wounds and was probably the result of an intratribal dispute.

Abstract: Recent theoretical work permits a characterization of loads in the cord layer of operating V-belts. Experimental evidence corroborating theory has been limited. Such evidence has been collected and is presented in this paper. Given are empirical relationships describing how peak strains across and along the belt occurring during an operating cycle vary with preload, transmitted torque, pulley diameter and speed. Representative plots are included to illustrate the dependence of strains on position around pulleys in the drive system. Comparisons of theoretical results and data collected during this study reveal potentially significant differences. Reasons for these differences are hypothesized. High strain rates in operating V-belt drives and their influence on maximum stress are discussed, as are subsidiary matters including belt instrumentation and strain-signal transmission.

The plutonic complex of the Meissen massif (northern margin of the Bohemian massif) comprises dioritic to mainly monzonitic and granitic rocks. The diorite to monzonite intrusions show major and trace element patterns typical for shoshonitic series. The chemical signatures of less crustally contaminated diorites are similar to arc-related shoshonitic rocks derived from continental lithospheric mantle (CLM) sources previously enriched by subduction of altered oceanic crust. Laser step heating 40Ar/39Ar analyses on actinolitic to edenitic amphiboles from geographically different occurrences of the monzonitic intrusion yielded concordant plateau ages as well as total gas ages ranging from 329.1±1.4 to 330.4±1.4 Ma and from 330.4±2.1 to 330.6±1.8 Ma, respectively. These cooling ages are indistinguishable from sensitive highresolution ion microprobe (SHRIMP) 238U/206Pb intrusion ages measured on magmatic zircon rims from the monzonite (Nasdala et al., submitted). This shows that the monzonite intrusion is probably not related temporally to active subduction because it postdates eclogites of the adjacent Saxonian Erzgebirge by approximately 20 Ma. The shoshonitic magmas intruded during strike-slip tectonism along the Elbe valley zone. The enrichment of their mantle sources may be of Upper Devonian/Lower Carboniferous age or older. Intrusions of shoshonitic to ultra-potassic (K-rich) rocks during the Upper Visean/Namurian are widespread in the Moldanubian zone. Based on similar ages and structural relationships a similar post-collisional setting to the Meissen shoshonitic rocks can be demonstrated. Most of these occurrences cut high-grade nappe units which were subducted during the Upper Devonian/Lower Carboniferous. In contrast to the Meissen massif, at least the ultra-potassic members of the Central and the South Bohemian batholiths were derived from CLM sources enriched by fluids or melts released from subducted oceanic crust and by greater portions of crustal material. Despite the similar post-collisional geodynamic setting of the K-rich intrusions, different enrichment processes generated mid-European Hercynian CLM sources with heterogeneous major and trace element and isotopic signatures. [ABSTRACT FROM AUTHOR]

Zusammenfassung Die Energiebilanz wird durch gegenseitige Abstimmung von vier Variablen aufrechterhalten: Nahrungsaufnahme, gespeicherte Energie, Arbeit und Wärmebildung. Diese Variablen unterliegen einer Kontrolle durch zentralnervöse Mechanismen. Für die nervösen Mechanismen bestehen zwei Informationswege: Einer über Afferenzen von den am Energiewechsel beteiligten Organen und ein zweiter über bestimmte Veränderungen, die im inneren Milieu als Folge eines Gewinns oder Verlustes an Energie auftreten. Wahrscheinlich ist die Anpassung der Nahrungsaufnahme an den Energiewechsel eine hypothalamische Funktion. Ein ventromediales Sättigungszentrum ruft durch Unterdrückung der Aktivität eines lateralen Freßzentrums einen Zustand der Sättigung hervor. Die hypothalamischen Kontrollzentren können durch eine Vielzahl möglicher Faktoren beeinflußt werden, wobei zwischen zwei biometrischen Anteilen zu unterscheiden ist: Einer Kurzzeit- und einer Langzeitregulation. Die Kurzzeitkontrolle der Nahrungsaufnahme scheint vorwiegend „glucostatischer“ Natur zu sein, während für die Langzeitregulation der Körperreserven ein „lipostatischer“ Mechanismus diskutiert wird. Einige Besonderheiten im Kohlenhydratstoffwechsel werden als günstige Voraussetzung für eine Kurzzeitregulation der Nahrungsaufnahme durch einen glucosensitiven Mechanismus erkannt. Grundlage der lipostatischen Theorie ist die Annahme, daß der Organismus täglich eine bestimmte Fettmenge mobilisieren muß, die vom Gesamtkörperfettbestand abhängig sein soll. — Vermutlich greifen Amphetamin und verwandte Substanzen mit „appetitzügelnden“ Eigenschaften direkt am hypothalamischen Anteil des zentralen Fütterungsmechanismus an. — Für die appetit- und gewichtsteigernde Wirkung von Cyproheptadin = 1-Methyl-4-(5-dibenzo[a,e,]-cycloheptatrienyliden)-piperidinhydrochlorid scheint weniger ein direkter Angriff an zentralnervösen Strukturen als eine indirekte Beeinflussung der für die Nahrungsaufnahme verantwortlichen hypothalamischen Zentren durch Wechselwirkungen hinsichtlich der Verfügbarkeit von Glucose und unveresterten Fettsäuren verantwortlich zu sein.

Zusammenfassung Der erste Teil einer Serie von Untersuchungen mit dem Ziel einer Aufklärung der appetit- und gewichtsteigernden Wirkung von Cyproheptadin = 1-Methyl-4-(5-dibenzo-[a,e]-cycloheptatrienyliden)-piperidinhydrochlorid umfaßt klinische Erfahrungen und Hormonjodstudien. Folgende Ergebnisse werden erzielt:

Zusammenfassung 1. An gastrobioptisch kontrollierten 16 Männern und 3 Frauen werden Veränderungen von Osmolalität, ionaler Zusammensetzung und Sekretionsraten des Magensaftes während tatsächlicher maximaler Säurestimulation und zusätzlicher Wirkung von Atropin über 2 Std beobachtet. Dazu werden durch intravenöse Dauerinfusion pro Stunde 2 mg Histalog/kg Körpergewicht zugeführt und bei 12 Personen während maximaler Histalogwirkung 0,5 mg Atropinsulfat intravenös injiziert.

Zusammenfassung Die Polyätiologie verschiedener Grundkrankheiten und moderne therapeutische Möglichkeiten zur Beseitigung des malignen Verlaufes einer arteriellen Hypertension lassen den Ersatz des Begriffes „maligne Hypertonie“ durch die Bezeichnung „akzelerierte Hypertonie“ angebracht erscheinen. Bis heute ist die Pathogenese einer sog. malignen Hypertonie nicht geklärt. Ein endgültiger Beweis für die Immunpathogenese der Akzeleration einer Hypertonie steht noch aus. Für den malignen Verlauf einer Hypertonie kann eine Stimulierung des Renin-Angiotensin-Aldosteronsystems nicht direkt verantwortlich gemacht werden. Eine solche Stimulierung wird umgekehrt nicht durch eine nekrotisierende Arteriolitis ausgelöst, da sich diese Veränderung unabhängig von einer arteriellen Hypertonie entwickeln kann. Vermutlich sind an der Regulierung der Reninfreisetzung nicht nur intrarenale Chemoreceptoren beteiligt. Der Nachweis einer vermehrten Aktivität von Renin und Erythropoetin im peripheren Plasma bei Patienten mit akzelerierter Hypertonie ist kein Grund zur Annahme, die Abgabe beider Stoffe würde durch einen gemeinsamen Mechanismus gesteuert. Andere Prinzipien, wie antihypertensive renomedulläre Faktoren, Hypervolämie usw., spielen bei der Akzeleration einer arteriellen Hypertonie keine erkennbare Rolle.

Zusammenfassung An gastrobioptisch kontrollierten 8 Männern und 2 Frauen ohne pathologischen Magenbefund werden Veränderungen von Osmolalität, ionaler Zusammensetzung und Sekretionsraten des Magensaftes während maximaler Säurestimulation unter dem Einfluß von intravenös appliziertem 4-Chlor-N-(2-furylmethyl)-5-sulfamoyl-anthranilsäure = Furosemid in einer Dosierung von 20 bzw. 40 mg geprüft. Dabei ergibt sich, daß Furosemid die Magensaftsekretion und die Funktion der Natriumtransportsysteme in der Magenschleimhaut in therapeutischen Dosen nicht erkennbar verändert.

Zusammenfassung: An insgesamt 37 Patienten und in tierexperimentellen Untersuchungen wird die Brauchbarkeit der Isotopennephrographie als klinisch-diagnostische Methode überprüft. Dabei ergibt sich folgendes:

Zusammenfassung An einem größeren Patientengut mit und ohne Nierenfunktionsstörungen werden nach mindestens viertägiger Vorbereitung mit einer eiweiß;- und natriumaren Diät unter standardisierten Versuchsbedingungen die Beziehungen zwischen der Plasmakonzentration von Reststickstoff (RN) einerseits und der renalen Inulinclearance (CIn) bzw. der Plasmakonzentration von „wahrem“ endogenem Kreatinin (PKr) andererseits geprüft.

Zusammenfassung An einer Anzahl 18 Std gedursteter, relativ proteinarm ernährter Personen mit und ohne Nierenfunktionsstörungen wird das Verhalten der den Harnkonzentrierungsmechanismus unter maximalem ADH-Einfluß begrenzenden Meßgrößen während akuter Belastung mit Harnstoff bzw. Kreatinin geprüft. Die Harnstoffbelastung erfolgt kombiniert peroral (6 g) und intravenös mit 10–20% iger Lösung. Kreatinin wird in 5% iger Lösung i.v. appliziert. Dabei ergibt sich folgendes:1.Bei allen untersuchten nierengesunden und nierenkranken hydropenischen Personen steigt die unter Oligurie bestimmte maximale Harnosmolalität (Uosm (max)) innerhalb 1 Std nach Beginn einer Harnstoffbelastung im Mittel um 56 (Spanne: 40 bis 72) mosm/kg H2O an. Gleichzeitig nehmen Harnzeitvolumen (V), osmolare Clearance (Cosm), Rückdiffusion von osmotisch freiem Wasser ( ) und osmotisches Konzentrationsverhältnis zwischen Urin und Plasma (U/Posm) leicht, aber bei allen Probanden im vergleichbaren Maße zu. Im Übergangsstadium einer Harnstoffbelastung läßt sich auf diese Weise die bekannte umgekehrte Proportionalität zwischenU/Posm undCosm bei Werten vonV bzw.Cosm um 1 bzw. 2 ml/min und 1,73 m2 nicht mehr nachweisen.2.Die bei Oligurie und Hydropenie durch Harnstoffbelastung hervorgerufene Mehrausscheidung von osmotisch aktivem Material kommt zu etwa 2/3 durch eine Zunahme vonV und zu etwa 1/3 durch eine Steigerung vonUosm (max) zustande. Die in der Zeiteinheit ausgeschiedene Natriummenge ist bei erhöhter Serumharnstoffkonzentration gesteigert. Dagegen zeigen die Natriumkonzentration im Harn und die Kaliumausscheidung unter akuter Harnstoffbelastung keine nennenswerte Änderung.3.Während Hydropenie und Oligurie bewirkt ein Anstieg der Serumkreatininkonzentration von durchschnittlich 0,88 auf maximal 10,8 mg/100 ml eine Tendenz zur Abnahme vonUosm (max) undU/Posm. Gleichzeitig sindV,Cosm, und renale Natriumausscheidung vergrößert. Die Kaliumausscheidung ändert sich nur wenig.4.Bei hydropenischen oligurischen Personen nimmt der relative Anteil von Kalium (mit monovalentem Anion) an der maximalen Harnosmolalität unter Kreatininbelastung in dem Maße ab, wie der Kreatininanteil zunimmt.5.Unter i.v. Kreatininbelastung ändert sich (gemessen während Infusion hypertonischer Mannitlösung) weder bei Nierengesunden noch bei Nierenkranken.6.Aus den Resultaten wird geschlossen, daß akute Harnstoffbelastung bei Oligurie zu einer Durchbrechung der sog. „osmotic ceiling“ (Smith 1956) führen kann und daß Kreatinin weder bei Nierengesunden noch bei Nierenkranken (ohne Retention harnpflichtiger Stoffe) am Aufbau eines hypertonischen medullären Interstitiums beteiligt ist. Die bei Nierenfunktionsstörungen oft beobachtete partielle Permeabilität gegenüber Kreatinin muß andere Nephronabschnitte als die Sammelrohre betreffen.

Zusammenfassung An relativ proteinarm und natriumarm ernährten, nicht vorgewässerten Patienten mit unterschiedlich ausgeprägter essentieller Hypertonie und normotonen nierengesunden Personen wird untersucht, inwieweit eine beschleunigte Natriumausscheidung während intravenöser Infusion von 5–15 ml/min einer 5- bzw. 6,7% igen Kochsalzlösung auf Störungen der tubulären Reabsorption von Natrium in verschiedenen Nephronabschnitten zurückzuführen ist. Dabei ergibt sich folgendes:

Zusammenfassung Es wird über eine neue inulinartige Substanz, Polyfructosan-S (PFS), berichtet, die gegenüber Inulin (In) einige Vorteile hat (völlige Löslichkeit in kaltem Wasser, Alkalistabilität, geringere Hydrolysegeschwindigkeit). Da die chemische Analyse von PFS in Urin und Plasma mit derjenigen von In identisch ist, können vergleichende Untersuchungen über die renale Clearance und das Verteilungsvolumen von PFS mit In nicht simultan durchgeführt werden.

Während Hydropenie werden an kreislaufkompensierten Patienten mit unterschiedlich ausgeprägter essentieller Hypertonie und an nierengesunden normotensiven Kontrollen die Effekte, die intravenöse Infusion von 5% Kochsalzlösung bzw. von 10–12,5% Mannitlösung auf die Rückgewinnung von osmotisch freiem Wasser (Tch2o) beim Harnkonzentrierungsvorgang ausüben, miteinander verglichen. Mit zunehmender Kochsalzdiurese strebt Tch2o keinem Maximum zu, sondern steigt bei einer osmolalen Clearance (Cosm) von mehr als 20 ml/min und 1,73 m2 Körperoberfläche progressiv mit Cosm über die bei vergleichbarer Mannitdiurese erzielten Maximalwerte an. Obgleich sich bei Patienten mit ausgeprägter essentieller Hypertonie funktionelle Störungen im Natriumstoffwechsel distaler Nephronabschnitte finden können, reagieren solche Probanden, solange die Nierenfunktion nicht nennenswert eingeschränkt ist, in dieser Beziehung qualitativ gleich wie gesunde Personen. Der progressive Anstieg von Tch2o mit zunehmender Kochsalzdiurese ist auch bei Werten von Cosm, die 25 bis 30 ml/min überschreiten, nachweisbar. Hierbei kann während hypertoner Mannitdiurese bereits eine Tendenz zur Verminderung von Tch2o auftreten. Bei nierengesunden normotensiven und leicht hypertensiven Personen erreicht Tch2o Werte in der Größenordnung von 9 ml/min, wenn Cosm 30 ml/min, jeweils bezogen auf 1,73 m2 Körperoberfläche, übersteigt.

Zusammenfassung: Whrend maximaler Surestimulation durch intravense Infusion von 2 mg Histalog/kg Krpergewicht und Stunde ruft intravense Applikation von 50 mg Etacrynsure beim Menschen keine signifikanten Vernderungen von Volumenrate und ionaler Zusammensetzung des Magensaftes hervor.

Summary 1. The effects of an oral application of xylitol over two weeks to 8 normal subjects aged 21 to 27 years have been studied with respect to fat and uric acid metabolism. There was an initial adaptation period of up to 7 days during which time the daily xylitol intake was increased from 15 g to 50 g without side effects. Observations were continued for 3 days after the cessation of xylitol administration.

Summary 1. In 20 normal volunteers, 17 to 28 years of age, the changes of fat and uric acid metabolism induced by a 100 min intravenous infusion of 5 ml/min of a 10% xylitol solution are studied for 240 minutes.

Zusammenfassung 1. Bei 882 Fällen von chronischer Nierenerkrankung (davon 342 Fälle mit Rest-N-Erhöhung) wurden nur sechs Fälle von Arthritis urica festgestellt, davon nur zwei Fälle mit sekundärer Gicht (= 0,23%).

Zusammenfassung Es wird die Frage geprüft, inwieweit Hormone und Pharmaka, die in verschiedenen Geweben die Konzentration von Adenosin-3',5'-cyclischem-monophosphat (cyclischem AMP) verändern können, die Bildung von Magensäure beim Menschen während maximaler Säurestimulation beeinflussen. Durch intravenöse Injektion von Stoffen, die strukturgebunden in verschiedenen Geweben die Aktivität von Adenylcyclase oder von 3',5'-AMP-Phosphodiesterase verändern, kann nur unter bestimmten Bedingungen eine Wirkung auf die Säuresekretion am stimulierten Magen erzielt werden. Vermutlich unterliegt der Abbau von cyclischem AMP nicht nur der Wirkung 3',5'-AMP-Phosphodiesterase. Verschiedene experimentelle Befunde werden im Hinblick auf die mögliche Bedeutung von cyclischem AMP bei der Bildung und Sekretion von Magensäure diskutiert. Mit einer Ausnahme stehen direkte Messungen des Gewebsgehaltes von cyclischem AMP in der Magenschleimhaut unter den beschriebenen Versuchsbedingungen noch aus. Die Fragen, ob cyclisches AMP oder eines seiner Stoffwechselprodukte Mittlersubstanz bei der Bildung von Magensäure ist und ob cyclisches AMP letzter Effektor einiger durch Hormone oder Pharmaka induzierten Änderungen der Säuresekretion durch die stimulierte Magenschleimhaut sein kann, bleiben vorläufig ungelöst.

Zusammenfassung An hydropenischen hypertensiven Personen wird das Verhalten der renalen Natriumausscheidung in individuell vergleichenden Untersuchungen während metabolischer Acidose und metabolischer Alkalose geprüft. Dazu werden 2 bis 10 ml/min 5%iger Lösungen von Natriumchlorid und anschließend von Natriumlactat intravenös infundiert. Bei vergleichbaren Werten von osmolaler Clearance (bis über 20 ml/min), glomerulär filtrierter Natriummenge (bis 32 mval/min) und ausgeschiedenem Natriumbetrag (bis 2,5 mval/min oder 9,5% des Natrium Load) ergibt sich kein Anhalt für eine unterschiedliche Behandlung von Natrium in verschiedenen Nephronabschnitten bei einem Wechsel von metabolischer Acidose zu metabolischer Alkalose. Auch läßt sich keine Abweichung der Kaliumausscheidung unter diesen Versuchsbedingungen nachweisen. Die Ergebnisse werden im Hinblick auf die hohe Permeabilität proximaler Tubulusabschnitte gegenüber Natrium diskutiert.

Zusammenfassung Bei Patienten, die operativ oder mit J131 wegen Hyperthyreose behandelt wurden, kommt es zum vorübergehenden Auftreten von Autoantikörpern gegen Thyreoglobulin. Diese sind ohne Einfluß auf die Stoffwechsellage und stehen in keiner Beziehung zum Ausmaß einer posttherapeutischen Verkleinerung des intrathyreoidalen Jodpools.

Under standardized experimental conditions it is shown that the uric acid concentration in human gastric juice is pH-dependent. The gastric uric acid concentration falls as a hyperbolic function with increasing acidity of gastric juice. Normally a concentration ratio of uric acid between gastric juice and plasma in the range of 0.2–0.4 will be found. These results are compatible with the conception of uric acid transport by means of non-ionic diffusion. In theoreticalmathematical considerations rate limiting factors on non-ionic diffusion of a weak acid from plasma into gastric juice are described.

Summary 16 patients with chronic renal failure undergoing regular hemodialysis therapy were studied. To each person 200 µCi THO were administered intravenously before and immediately after hemodialysis. In comparison with the corresponding predialytic values the decrease of the volume of distribution of THO 4 hrs after the end of a dialysis was larger than the loss of body weight. The average decrease of the body weight during dialysis was 1.05 ± 0.80 kg (P < 0.001), whereas the average reduction of the volume of distribution of THO amounted to 4.63 ± 3.31 1 or 6.35 ± 4.40% of the body weight (P < 0.001 in each case). The difference between the loss of body weight and the absolute reduction of the estimated volume of total body water was highly significant (P < 0.001). The postdialytic imbalance of the distribution of isotopic water is abolished 6 hrs after the end of a hemodialysis.

Summary The response of human gastric mucosa to intravenous infusion of adenosine-3',5'-cyclic monophosphate (cAMP) was studied in 12 subjects with normal cardiovascular system. Administration in large doses of 1.0 to 1.5 mg/kg body weight and per minute of exogenous cAMP slightly but significantly stimulated hydrochloric acid secretion during the infusion period. The effect of cAMP however, was much smaller than that of pentagastrin in doses used to eliciting maximal acid secretion. The appearance of serious side effects of cAMP rules out an elevation of the quantity infused of the substance to produce a possible enhancement of the acid-stimulating action. Administered at a dose of 0.5 mg/kg per minute, cAMP does not significantly alter volume rate nor secretory rates of hydrogen ions and chloride compared with basal acid output. These findings support the theory that cAMP plays an important role in the production and secretion of gastric acid.

The novel Coronavirus (COVID-19) has created a worldwide deadly pandemic that has become a major public health challenge. All semi-urgent and elective medical care has come to a halt to conserve capacity to care for patients during this pandemic. As the numbers of COVID-19 cases decrease across Canada, our healthcare system also began to reopen various facilities and medical offices. The aim for this document is to compile the current evidence and provide expert consensus on the safe return to clinic practice in Otolaryngology – Head & Neck Surgery. These recommendations will also summarize general precaution principles and practical tips for office across Canada to optimize patient and provider safety. Risk assessment and patient selection are crucial to minimizing exposure to COVID-19. Controversial topics such as COVID-19 mode of transmission, duration of exposure, personal protective equipment, and aerosol-generating procedures will be analyzed and discussed. Practical solutions of pre-visit office preparation, front office and examination room set-up, and check out procedures are explored. Specific considerations for audiology, pediatric population, and high risk AGMPs are also addressed. Given that the literature surrounding COVID-19 is rapidly evolving, these guidelines will serve to start our specialty back into practice over the next weeks to months and they may change as we learn more about this disease.

Among smart activable nanomaterials used for nanomedicine applications, carbon-based nanocomposites are well known to ensure phototherapy while their use for controlled drug delivery is still rarely investigated. In this work, original hybrid mesoporous silica (MS)–coated carbon nanotubes (CNTs) nanoplatforms have been designed to provide phototherapy combined with drug release mediated by NIR laser excitation. The responsive CNT@MS are chemically modified with original isobutyramide (IBAM) grafts acting as non-covalent binders, which ensure a very high drug loading capacity (≥to 80 wt%) of the antitumor drug doxorubicin (DOX) as well as the final adsorption of a human serum albumin (HSA) shell as biocompatible interface and drug gate-keeping. The drug is demonstrated to unbind from the nanocomposite only upon photothermal excitation and to release in the solution. Such smart platforms are further shown to deliver drug upon several pulsatile NIR excitations with controlled temperature profiles. Regarding antitumor action, we demonstrate here that the NIR light induced photothermic effect from the nanocomposites is the main effect accounting for cancer cell toxicity and that DOX delivery mediated by the NIR light brings an additional toxicity allowing a synergistic effect to efficiently kill tumor cells. Finally, when our nanocomposites are embedded within a hydrogel mimicking extracellular matrix, the resulting smart responsive scaffolds efficiently release DOX upon NIR light to the cells localized above the composite hydrogel. These results demonstrate that such nanocomposites are highly promising as new components of implantable antitumor scaffolds that are able to respond to external stimuli in time and location for a better disease management.

Summary A total of 60 newly admitted hospital patients with maturity onset diabetes mellitus and normal kidney function were studied. They were either treated only with a diet (group I), or also with blood-sugar lowering sulfonylureas (group II). Some patients had become insulin-dependent (group III). It was found that the mean serum concentration of lipoprotein Lp(a) was significantly increased in patients in groups II and III, but not in group I, as compared to the median of the group of 51 normal controls. All three groups of diabetics showed normal LDL cholesterol levels but lowered HDL cholesterol values, most pronouncedly in group II. Groups I and II, but not group III, showed a significant increase of the mean serum concentration of triglycerides and of the mean values for the LDL/HDL ratio as compared to normal controls. A correlation between the serum concentration of Lp(a) on the one hand, and the HbA1 value, LDL cholesterol, VLDL, HDL cholesterol, phospholipids, triglycerides and total cholesterol on the other, cannot be found for any of the three groups of diabetics.

Without Abstract:

Summary Oral administration of benzbromarone at daily doses of 100 mg or 300 mg over a period of 3 or 6 days does not produce a significant change of the excretion rates of allantoin in the 24-h-urines of humans in a normouricemic or hyperuricemic state. Therefore, the theoretically improbable assumption that benzbromarone may induce an increased elimination of uric acid by an enteral pathway cannot be accepted any longer. Failing additional direct effects upon purine metabolic pathways (Sorensen and Levinson, 1976) benzbromarone exerts its hypouricemic action solely by uricosuric properties.

Summary Twenty male hyperuricaemic patients with normal kidney function were studied and it was found that the serum concentrations and excretions rates in the 24-hour urine of allopurinol and oxipurinol do not differ significantly after 9 days of oral treatment with either 300 mg allopurinol or a combination of 300 mg allopurinol and 60 mg benzbromarone daily. The sum of the excretion rates of the two pyrazolopyrimidines in the 24-hour urine represents 80.9% and 77.1%, respectively, of the daily dose of ailopurinol given alone or in combination with benzbromarone. As expected, the hypouricaemic effect of the combined therapy turned out to be stronger than that observed after monotherapy with allopurinol, due to the uricosuric component of benzbromarone. The difference was found to be highly significant.