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CR carbonaceous chondrites are of major interest since they contain some of the most primitive organic matter known. However, aqueous alteration has more or less overprinted their original features in a way that needs to be assessed. This study was initiated by comparing the mineralogy and modal abundances of the most altered CR1 chondrite, GRO 95577, to a less altered CR2. Calculated element distributions imply that GRO 95577 may result from aqueous alteration of Renazzo by an isochemical process on their parent asteroid, whose mineralogical composition was estimated ( Unaltered CR shown included table).

Bilateral surface-active minerals with excess positive charge concentrate glycolate and trimetaphosphate ion from l0(-3) m aqueous solution to half-saturation of the internal surface sites, and induce phosphorylation of glycolate ion in the mineral with trimetaphosphate, sorbed from l0(-2) m solution. By utilizing reactants from dilute solution at near-neutral pH, and eliminating the need for participating organic nitrogen compounds, the reaction comprises several elements considered necessary for geochemical realism in models for molecular evolution.

We have prepared a [32P]-labeled oligonucleotide probe carrying a ureido (-NH-CO-NH2) function at its 3'-terminus. This labeled oligomer was used to study polycondensations of urea and formaldehyde and of various phenols and formaldehyde in aqueous solution. The formation of formaldehyde copolymers attached to the amido-function of the probe was monitored by gel electrophoresis. Our results are generally in agreement with those obtained using conventional techniques. Our method is suitable for monitoring potentially prebiotic polycondensation reactions involving formaldehyde.

We have prepared a [32P]-labled oligonucleotide probe carrying a free primary amine at its 3'-terminus. This probe is used to initiate polymerization of aziridine (ethyleneimine) in aqueous solution. The nature of the oligomeric products and the kinetics of their formation are then monitored by gel electrophoresis. Our results are generally consistent with those obtained using conventional techniques. We have also investigated the effect of polyanionic templates on the rate of oligomerization of aziridine. We find that water-soluble polyanions generally accelerate the polymerization. The sodium salt of polymethacrylic acid is the most effective of the templates that we studied. The methods introduced in this paper should be applicable to a variety of polymerization reactions in aqueous solution. They should greatly simplify the screening of potentially prebiotic polymerization reactions.

Urazole is a five-membered heterocyclic compound which is isosteric with uracil's hydrogen-bonding segment. Urazole reacts spontaneoulsy with ribose (and other aldoses) to give a mixture of four ribosides: alpha and beta pyranosides and furanosides. This reaction occurs in aqueous solution at mild temperatures. Thermodynamic and kinetic parameters for the reaction of urazole with ribose were determined. In contrast, uracil is completely unreactive with ribose under these conditions. Urazole's unusual reactivity is ascribed to the hydrazine portion of the molecule. Urazole can be synthesized from biuret and hydrazine under prebiotic conditions. The prebiotic synthesis of guanazole, which is isosteric in part to diaminopyrimidine and cytosine, is accomplished from dicyandiamide and hydrazine. Kinetic parameters for both prebiotic reactions were measured. Urazole and guanazole are transparent in the UV, which would be a favorable property in the absence of an ozone layer on the early Earth. Urazole makes hydrogen bonds with adenine in DMSO similar to those of uracil, as established by H NMR. All of these properties make urazole an attractive potential precursor to uracil and guanazole a potential precursor to cytosine in the RNA or pre-RNA world.

Proteus syndrome is a rare genetic disease characterized by an asymmetrical growth of individual parts of the body and has only been described in single cases. This patient presented with recurrent manifestations of a laryngeal and hypopharyngeal lymphangioma, which were treated with laser surgery, systemic therapy, and sclerotherapy. The reported data depict the diagnosis and treatment in the department of otorhinolaryngology, head and neck surgery of the university hospital Heidelberg from 2019 until May 2023. The recurrent endoscopy of the upper airway was performed using a flexible HD-endoscope and the Visera Elite video tower from Olympus, Hamburg. The 29-year old female patient initially presented in February 2019 with stridor and exertional dyspnea due to a lymphatic malformation of the left larynx and hypopharynx. In April 2019 there was no improvement by sclerotherapy with Picibanil, so that systemic therapy with the PIK3CA inhibitor alpelisib was initiated (03-07/2020) and discontinued due to a high side effect profile. In the course of 2021-2023, three microlaryngoscopies with laser surgical resection and renewed sclerotherapy of the lymphangioma with Picibanil were carried out due to fluctuating findings. After these interventions a stable disease could be established until May 2023. Laser surgical therapy is currently described as the therapy of choice in lymphangiomas in the head and neck region and also showed the highest effectiveness in our patient. In case of airway obstruction in particular, it can bring rapid symptom relief. Alternatively, and with a lower surgical risk, local improvements have been reported by sclerotherapy, which was less effective in the presented case. Rare syndromic diseases require multidisciplinary collaboration. In the case of laryngeal lymphangiomatosis, other treatment options should be considered in addition to surgical excision, especially in the case of recurrence., Competing Interests: The authors declare that they have no competing interests., (© 2023 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd.)