[Robotic vs. laparoscopic right hemicolectomy-An analysis of costs]. / Robotische vs. laparoskopische Hemikolektomie rechts ­ eine Kostenanalyse.

The use of robotic surgical methods for performing right-sided hemicolectomy has been somewhat controversial, primarily due to concerns related to costs. The purpose of this study is to document the initial robotic right hemicolectomies conducted at our institution and to compare them with a laparoscopic reference group. A significant focus of this study is the detailed analysis of the costs associated with both techniques within the German healthcare system.Surgical and cost-related data for 34 cases each for robotic and laparoscopic right-sided hemicolectomy performed at Nürnberg Hospital were compared. This comparison was conducted through a retrospective single-center case-matched analysis. Cost analysis was carried out following the current guidelines provided by the Institute for the Hospital Remuneration System (InEK) of Germany.The average age of the patient cohort was 70 years, with a male patient proportion of 57.4%. Analysis of perioperative parameters indicated similar outcomes for both surgical techniques. Regarding the incidence of complications of Clavien-Dindo stages III-V (8.8% vs. 17.6%; p = 0.48), a positive trend towards robotic surgery was observed. The cost analysis showed nearly identical total costs for the selected cases in both groups (mean €13,423 vs. €13,424; p = 1.00), with the most significant cost difference noted in surgical (operative) costs (€5,779 vs. €3,521; p < 0.01). The lower costs for laparoscopic cases were primarily due to the reduced material costs (mean €2,657 vs. €702; p < 0.05).In conclusion, both surgical approaches are clinically equivalent, with only minor differences in the total case costs.

[Impact of the COVID pandemic on treatment of bariatric patients in Germany-An analysis of the national StuDoQ/MBE register]. / Auswirkungen der COVID-Pandemie auf die Versorgung bariatrischer Patienten in Deutschland ­ eine Analyse des nationalen StuDoQ/MBE-Registers.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic the standard inpatient care of patients was restricted to increase overall and intensive care capacity reserves for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected persons. OBJECTIVE: This article presents the impact of the COVID-19 pandemic on the surgical and postoperative care of bariatric patients in Germany. MATERIAL AND METHODS: A statistical analysis of the national StuDoQ/MBE register data for the period from 1 May 2018 until 31 May 2022 was performed. RESULTS: Throughout the entire study period there was a continuous increase in documented operations, which continued even during the COVID-19 pandemic. A significant intermittent decline in surgery performed was observed only during the imposition of first lockdown in the months of March to May 2020, with a minimum number of 194 cases performed monthly in April 2020. The pandemic had no measurable effect on the surgically treated patient population, the type of surgical procedure, the perioperative and postoperative outcomes and follow-up care. CONCLUSION: Based on the results of the StuDoQ data and the current literature, it can be deduced that bariatric surgery can be carried out with no increased risk during the COVID-19 pandemic and the quality of postoperative care is not impaired.

Electrochemical reduction of carbon dioxide on pyrite as a pathway for abiogenic formation of organic molecules.

A wide spectrum of electrode potentials of minerals that compose sulfide ores enables the latter, when in contact with hydrothermal solutions, to form galvanic pairs with cathode potentials sufficient for electrochemical reduction of CO2. The experiments performed demonstrated the increase of cathode current on the rotating pyrite disc electrode in a range of potentials more negative than -800 mV in presence of CO2. In high-pressure experiments performed in a specially designed electrochemical cell equipped with a pyrite cathode and placed into autoclave, accumulation of formate was demonstrated after 24 hr passing of CO2 (50 atm, room temperature) through electrolyte solution. The formation of this product started on increasing the cathode potential to -800 mV (with respect to saturated silver chloride electrode). The yield grew exponentially upon cathode potential increase up to -1200 mV. The maximum current efficiency (0.12%) was registered at cathode potentials of about -1000 mV. No formate production was registered under normal atmospheric pressure and in the absence of imposed cathode potential. Neither in experiments, nor in control was formaldehyde found. It is proposed that the electrochemical reduction of CO2 takes part in the formation of organic molecules in hydrothermal solutions accompanying sulfide ore deposits and in 'black smokers' on the ocean floor.

Potency of bupivacaine stereoisomers tested in vitro and in vivo: biochemical, electrophysiological, and neurobehavioral studies.

BACKGROUND: Chiral local anesthetics, such as ropivacaine and levobupivacaine, have the potential advantage over racemic mixtures in showing reduced toxic side effects. However, these S-(levo, or "-")isomers also have reportedly lower potency than their optical antipode, possibly resulting in no advantage in therapeutic index. Potency for local anesthetics inhibiting Na+ channels or action potentials depends on the pattern of membrane potential and so also does the stereopotency ratio. Here the authors have quantitated the stereopotencies of R-, S-, and racemic bupivacaine, comparing several in vitro assays of neuronal Na+ channels with those from in vivo functional nerve block, to establish relative potencies and to understand better the role of different modes of channel inhibition in overall functional anesthesia. METHODS: The binding of bupivacaine to Na+ channels was assessed indirectly by its antagonism of [3H]-batrachotoxin binding to rat brain synaptosomes. Inhibition of Na+ currents by bupivacaine was directly assayed in voltage-clamped GH-3 neuroendocrine cells. Neurobehavioral functions were disrupted by bupivacaine percutaneously injected (0.1 ml; 0.0625-1.0%) at the rat sciatic nerve and semiquantitatively assayed. Concentration-dependent actions of R-, S-, and racemic bupivacaine were compared for their magnitude and duration of action. RESULTS: Competitive batrachotoxin displacement has a stereopotency ratio of R:S = 3:1. Inhibition of Na+ currents with different prepulse potentials shows that S > R potency when the membrane is hyperpolarized, and R > S potency when it is depolarized from normal resting values. Functional deficits assayed in vivo usually demonstrate no consistent enantioselectivity and only a modest stereopotency (R:S = 1.2-1.3) for peak analgesia achieved at the lowest doses. Other functions display no significant stereopotency in either the degree, the duration, or their product (area under the curve) at any dose. CONCLUSION: Although the in vitro actions of bupivacaine showed stereoselectivity ratios of 1.3-3:1 (R:S), in vivo nerve block at clinically used concentrations showed much smaller ratios for peak effect and no significant enantioselectivity for duration. A primary role for the blockade of resting rather than open or inactivated Na+ channels may explain the modest stereoselectivity in vivo, although stereoselective factors controlling local disposition cannot be ruled out. Levo-(S-)bupivacaine is effectively equipotent to R- or racemic bupivacaine in vivo for rat sciatic nerve block.

Structure-activity relation of N-alkyl tetracaine derivatives as neurolytic agents for sciatic nerve lesions.

BACKGROUND: N-butyl tetracaine has local anesthetic and neurolytic properties. An injection of this drug at the rat sciatic notch produces rapid onset and nerve impairment lasting > 1 week. This study aimed to elucidate the structure-activity relation of various tetracaine derivatives to design better neurolytic agents. METHODS: N-alkyl tetracaine salts (n = 2-6) were synthesized, and their ability to elicit sciatic nerve impairment of sensory and motor functions in vivo was tested in rats. A single dose (0.1 ml at 37 mM) was administered close to the sciatic nerve at the sciatic notch. Regeneration was assessed morphologically in transverse sections of treated nerves. Finally, the drug potency in blocking Na+ currents was studied under voltage-clamp conditions. RESULTS: N-ethyl and N-propyl tetracaine derivatives were non-neurolytic and elicited complete sciatic nerve block lasting 3-7 h. In contrast, N-butyl, N-pentyl, and N-hexyl tetracaine derivatives were strong neurolytic agents and elicited functional impairment of sciatic nerve for > 1 week. All derivatives were strong Na+ channel blockers, more potent than tetracaine if applied intracellularly. External drug application showed marked differences in their wash-in rate: tetracaine > N-hexyl > N-butyl > N-ethyl tetracaine. All derivatives were trapped within the cytoplasm and showed little washout within 7 min. CONCLUSIONS: When n-alkylation is 4-6, n-alkyl tetracaine appeared as a strong neurolytic agent. Neurolytic derivatives retained their local anesthetic activity and elicited rapid onset of nerve block after injection. Such derivatives are potential local anesthetic-neurolytic dual agents for chemical lesions of the sciatic nerve.

Neurophysiologic actions and neurological consequences of veratridine on the rat sciatic nerve.

BACKGROUND: The quest for a drug that would provide analgesia with minimal motor deficiency, through the selective inhibition of impulses in small-diameter fibers, was brightened by a previous report of veratridine's C-fiber-selective actions on the isolated rabbit vagus nerve. The goal of the present research was to demonstrate the same actions on rat sciatic nerve in vitro and to observe the functionally differential blockade in the rat in vivo. METHODS: Sciatic nerves were removed from rats, mounted in a recording chamber, wherein a 1-cm length of the ensheathed nerve was superfused with the plant alkaloid veratridine (2 microM) in bicarbonate-buffered Liley's solution, and the compound action potential (CAP) was stimulated supramaximally to give A- and C-fiber elevations. Onset, steady-state, and recovery from veratridine effects were assayed for a range of stimulus frequencies. Open-field behavior and quantitative neurological assessments of proprioception, motor function, and nociception were tested in 15 trained rats after injection near the sciatic nerve of 0.1 ml veratridine at 0.5, 0.7, and 1.0 mM each plus epinephrine (1:200,000). RESULTS: Veratridine inhibited the C-fiber component of the CAP in a frequency-dependent manner. At 0.1 Hz the CAP was 65% of the control amplitude, 50% at 0.5 Hz, and 40% at 5 Hz. A-fiber elevations were unattenuated at stimulus frequencies as high as 50 Hz. Steady-state inhibition was reached 5 min after drug administration, and recovery from the effects was 30% complete by 15 min of drug washout. Proprioception, measured as a "hopping" or "placing" reaction, was inhibited dose dependently by maximum degree and for durations of, respectively, 0.5 mM, 61%, 180 min; 0.7 mM, 100%, 360 min; and 1 mM, 100%, 420 min. Extensor postural thrust, as a measure of motor function, was inhibited by and for 0.5 mM, 77%, 240 min; 0.7 mM, 99%, 390 min; and 1 mM, 100%, 420 min. Analgesia, as a prolonged withdrawal latency to a noxious thermal stimulus, had the following profile: 0.5 mM, 10%, 30 min; 0.7 mM, 52%, 150 min; and 1 mM, 66%, 150 min. CONCLUSIONS: Despite the fact that veratridine gave a C-fiber preferential blockade in the isolated sciatic nerve, heightened analgesia over motor block was not achieved in vivo. Indeed, just the opposite occurred. If preferential C-fiber blockade also occurs in vivo, then its traditionally expected correlation with analgesia must be re-examined.

N-butyl tetracaine as a neurolytic agent for ultralong sciatic nerve block.

BACKGROUND: Neurolytic agents such as phenol (5% to 10%) and absolute alcohol have long been used clinically to destroy the pathogenic nerve regions that manifest pain. Both phenol and alcohol are highly destructive to nerve fibers. However, these agents exert only weak local anesthetic effects and therefore are difficult to administer to alert patients without pain. This report describes a tetracaine derivative that displays both local anesthetic and neurolytic properties. Studies with such a compound may lead to the design of neurolytic agents that are more effective and more easily administered than phenol and alcohol. METHODS: A tetracaine derivative, N-butyl tetracaine quaternary ammonium bromide, was synthesized, and its ability to elicit sciatic nerve block of sensory and motor functions in vivo was tested in rats. A single dose of 0.1 ml N-butyl tetracaine at 37 mM was injected into the sciatic notch. Transverse sections of treated sciatic nerves were subsequently examined to determine the neurolytic effect of this drug. Finally, the local anesthetic properties of N-butyl tetracaine were studied in vitro; both tonic inhibition and use-dependent inhibition of Na+ currents in neuronal GH3 cells were characterized under whole-cell voltage-clamp conditions. RESULTS: N-butyl tetracaine at 37 mM (equivalent to 1.11% tetracaine-hydrochloric acid concentration) elicited prolonged sciatic nerve block of the withdrawal response to noxious pinch in rats for more than 2 weeks. The withdrawal response was fully restored after 9 weeks. Parallel to sensory block, motor functions of the hind legs were similarly blocked by this drug. Morphologic examinations 3 and 5 weeks after a single injection of drug revealed degeneration of many sciatic nerve fibers, consistent with the results of functional tests. Finally, N-butyl tetracaine was found to be a potent Na+ channel blocker in vitro. It produced strong tonic and use-dependent inhibition of Na+ currents with a potency comparable to that of tetracaine. CONCLUSIONS: A single injection of N-butyl tetracaine produces ultralong sciatic nerve block in rats. This compound possesses both local anesthetic and neurolytic properties and may prove useful as a neurolytic agent in pain management.

[A comparison of the amount of DNA in the sporoplasm nuclei of the myxosporidian and actinosporidian phases of the life cycle of the parasitic protozoan Zschokkella nova--a representative of the Myxozoa type]. / Sravnenie kolichestva DNK v iadrakh sporoplazm miksosporeinoi i aktinosporeinoi faz zhiznennogo tsikla paraziticheskogo prosteishego Zschokkella nova--predstavitelia tipa Myxozoa.

Average DNA amounts in sporoplasm nuclei of the actinosporean and myxosporean developmental phases of Z. nova were compared. The average DNA amount per one, presumably diploid, sporoplasm nucleus of the actinosporean phase spores was twice as large as the average summarized DNA amount in two, presumably haploid, nuclei of the myxospsorean phase spores of Z. nova. It is suggested that sporoplasm nuclei in the actinosporean phase spores of Z. nova are diploid postsynthetic, whereas sporoplasm nuclei of the myxosporean phase spores are haploid. The data do not contradict the earlier supposition (Uspenskaya, 1955a, 1955b), that the investigated spores may be developmental stages of the same organism. The data support the idea of haploidy of the myxosporean phase spores (Uspenskaya, 1984) and diploidy of the actinosporean phase spores (Marques, 1984) in Myxozoa.

Quaternary ammonium derivative of lidocaine as a long-acting local anesthetic.

BACKGROUND: Use of long-acting local anesthetics that elicit complete neural blockade for more than 3 h often is desirable in pain management. Unfortunately, clinically available local anesthetics are in general not suitable for prolonged analgesia. This report describes the organic synthesis and functional testing of a lidocaine derivative that appears to fulfill the criteria of long-acting local anesthetics. METHODS: A lidocaine derivative, N-beta-phenylethyl lidocaine quaternary ammonium bromide, was synthesized, and its ability to inhibit Na+ currents in cultured rat neuronal GH3 cells was tested in vitro under whole-cell voltage clamp conditions. Neurologic evaluation of sciatic nerve block of sensory and motor functions in vivo was subsequently performed in rats. RESULTS: N-beta-phenylethyl lidocaine was found to be a potent Na+ channel blocker in vitro. It produced both tonic and use-dependent blocks of Na+ currents that exceeded lidocaine's effects by a factor of > 2 (P < 0.05). In vivo, N-beta-phenylethyl lidocaine elicited a prolonged and complete sciatic nerve block of the motor function and the withdrawal response to noxious pinch that was 3.6- and 9.3-fold longer than that of lidocaine (P < 0.001), respectively. CONCLUSIONS: In an attempt to elicit prolonged local anesthesia, a quaternary ammonium derivative of lidocaine containing a permanent charge and an additional hydrophobic component was synthesized. Complete sciatic neural blockade of more than 3 h was achieved with this derivative. Of note, sensory blockade was prolonged to a greater extent than motor blockade. The approach used in this study may prove useful for developing new drugs applicable in pain management.