[A rationale basis for airways conditioning: too wet or not too wet? ]. / Una base razionale per il condizionamento delle vie aeree: umidificare troppo o non troppo?

Medical gases conditioning during mechanical invasive ventilation is nowadays a problem. In fact, in spite of conditioning guidelines, absolute humidity (AH) into 25-35 mg/l, clinical evaluation of the optimal level of airway humidification has not yet been established with certainty. Physiologically, during spontaneous respiration the airway hydric balance, inspiratory AH expiratory AH, is negative of 27 mg/l about. Usually the patients on mechanical ventilation have an expiratory AH of 32-33 mg/l. An overhumidification of inspired gases, positive airway hydric balance, gives anatomic-physiological alterations of airways and lung parenchyma. During invasive mechanical ventilation, the practice of active hot humidifiers has a positive or level airway hydric balance. We think that inspired AH must be equal to expired AH to maintain an airway hydric balance at least level. At last, the temperature of inspired gases, with active hot humidifiers, shouldn't exceed 32-34 degrees C.

Semisynthetic beta-Lactam antibiotics. II. Penicillins from alpha-hydrazinoarylacetic acids.

A number of penicillins (2) have been synthesized from the alpha-hydrazinoarylacetic acids (4) via the activated chloride hydrochlorides (5) or via the mixed anhydride of the corresponding N2-benzyloxycarbonyl derivatives (6). The penicillins, 2b, e, j, show good activity against gram-positive and gram-negative bacteria and enhanced penicillinase resistance in comparison with ampicillin.

Synthesis of new alpha-hydrazinoarylacetic acids and derivatives.

The synthesis of some alpha-hydrazinoarylacetic acids (I) by reaction of alpha-bromoarylacetic acids with hydrazine, alkylhydrazines and carbobenzyloxyhydrazines is described. Reduction of the hydrazones of 2- and 3-thienylglyoxylic acids provided a general and effective route to the thienylic series. In view of the use of compounds (I) for the preparation of new penicillins, the experimental conditions for their conversion into cyclohexylamides (XI) via the corresponding carbobenzyloxyderivatives (III) were also investigated.