Effect of I/E ratio on mean alveolar pressure during high-frequency oscillatory ventilation.

This study investigated factors contributing to differences between mean alveolar pressure (PA) and mean pressure at the airway opening (Pao) during high-frequency oscillatory ventilation (HFOV). The effect of the inspiratory-to-expiratory time (I/E) ratio and amplitude of oscillation on the magnitude of - Pao (Pdiff) was examined by using the alveolar capsule technique in normal rabbit lungs (n = 4) and an in vitro lung model. The effect of ventilator frequency and endotracheal tube (ETT) diameter on Pdiff was further examined in the in vitro lung model at an I/E ratio of 1:2.

High frequency ventilation.

The 1990s have seen a dramatic resurgence of interest in high frequency ventilation (HFV). The role of HFV in the rescue of infants failing conventional mechanical ventilation (CMV) is now relatively well established. However, the wider role of HFV in the routine management of respiratory failure in the newborn is more contentious.

Vitamin D deficiency in infants and young children born to migrant parents.

Objective: To determine the current modes of presentation for the development of nutritional vitamin D deficiency in Melbourne children.

Methodology: A retrospective descriptive review was undertaken of the case records of children less than 5 years of age discharged from three Melbourne hospitals with a diagnosis of vitamin D deficiency or hypocalcaemia from January 1992 to January 1994.

Results: The study identified 13 infants and young children whose hospital admission was related to nutritional vitamin D deficiency.

Enhanced cis-platinum ototoxicity in children with brain tumours who have received simultaneous or prior cranial irradiation.

We report on four children who received cis-platinum simultaneously with, or in one case 10 months after, cranial irradiation and experienced exaggerated ototoxicity affecting all audible frequencies. The hearing loss was severe, affecting the critical areas for speech perception, and necessitated the provision of bilateral hearing aids. The audiograms of these patients are shown and compared to those of four children who had received cis-platinum as part of their treatment for neuroblastoma but without cranial irradiation.

Differential in vitro effects of recombinant alpha-interferon and recombinant gamma-interferon alone or in combination on the expression of melanoma-associated surface antigens.

The effect of individual in vitro concentrations of recombinant alpha-interferon species A (rIFN-alpha-A), recombinant gamma-interferon (rIFN gamma), and combinations of both interferons on the expression of melanoma-associated surface antigens p97 and the high molecular weight proteoglycan (HWM-MAA-240K) as detected by monoclonal antibodies (MoAb) 96.5 and ZME 018 respectively, was examined. rIFN-alpha-A at optimal concentrations of 50 and 500 U/ml caused significant (p less than 0.

Cell-layer-associated proteolytic cleavage of the telopeptides of type I collagen in fibroblast culture.

In human skin fibroblast cultures a fraction of the procollagen that was processed to collagen and remained in the cell layer was further proteolytically modified by removal of both N- and C-terminal telopeptides. The proteolytic activity was associated with the cell layer, since secreted collagens were found always to contain intact telopeptides. The inclusion of neutral polymers, which caused the accumulation of the collagen in the cell layer [Bateman, Cole, Pillow & Ramshaw (1986) J.

Induction of procollagen processing in fibroblast cultures by neutral polymers.

In cultures of dermal fibroblasts, procollagen and the intermediates pC- and pN-collagen accumulated in the culture medium with little further processing to collagen. When polyethylene glycol (PEG) or other neutral polymers were added to fibroblast culture medium, no collagen or procollagen was found in the medium, but all the collagen was associated with the cell layer. The type I procollagen was fully processed to collagen with an initial transient accumulation of pN-collagen, and the processed collagen formed covalently cross-linked dimers.

Infantile hematomyelia complicating electrocardioversion.

A premature male infant survived for eight months with significant cardiorespiratory problems. He developed a sudden, unexplained cardiorespiratory arrest that required vigorous resuscitation with apparent electrical cardioversion. Subsequent postmortem examination demonstrated focal and confluent hemorrhages in the thoracic and lumbar cord.

The action of iron on local Klebsiella infection of the skin of the guinea-pig and its relation to the decisive period in primary infective lesions.

The infectivity of 16 strains of Klebsiella spp. and its modification by systemic and local ferric iron were tested in the skin of the guinea-pig. The in vivo proliferation of 11 strains was enhanced in varying degrees by Fe+++ (E + strains); 5 strains (Eo) were not enhanceable even by large doses of Fe+++.