Diagnosis of Pneumocystis carinii pneumonia

Pneumocystis carinii is the prime opportunistic pathogen of our time, the leading cause of fatal pneumonia in the increasing number of immunosuppressed subjects encountered on oncology and transplant programmes' and in subjects with the acquired immuno-deficiency syndrome (AIDS).     

Pneumocystis carinii shows DNA homology with the ustomycetous red yeast fungi

Pneumocystis carinii causes life-threatening pneumonia in T-lymphocyte-immunodeficient subjects in transplant and oncology units or with acquired immune deficiency syndrome (AIDS). Recent DNA homology studies show P. carinii to be a fungus. To investigate the biology and epidemiology of this parasite further, we elected to determine for it a more precise taxonomic assignment within the fungal kingdom. We screened a wide range of organisms representing the major orders of fungi using DNA amplification and subsequently sequenced a portion of the mitochondrial gene encoding the large subunit ribosomal RNA. Our data show that the opportunistic pulmonary pathogen P. carinii is closely related to the ustomycetous red yeast fungi, a group which includes organisms that are extensively distributed throughout the environment and which release many widely dispersed airborne spores.     

The ecology, morphology and behaviour of Bakerdania elliptica (Acari: Prostigmata: Pygmephoridae), a mite associated with terrestrial isopods

In deciduous woodlands near to Bristol, South-west England, about one in ten specimens of the woodlouse Oniscus asellus (L.) are infested with Bakerdania elliptica (Krczal, 1959), a small pygmephorid mite of about 200 pm in length. Woodlice in the field rarely carry more than three mites, which are usually attached to the mid or lateral regions of the sixth and seventh pereonites on the ventral surface of the isopod. These 'favoured sites' correspond to regions of the exoskeleton of the woodlouse which are free from abrasion as they move through leaf litter. Mites removed from these areas and replaced on the first pereonite return to a favoured site, usually within 30 min. During this process they exhibit four distinct types of behaviour.]
Uninfested specimens of Oniscus usellus maintained in laboratory tanks on leaf litter from their 'own' site all become infested with mites within a week. The number of mites on the isopods increases rapidly under these conditions. After six weeks, each individual carries a mean of about 50 mites. The level of infestation is subsequently stable, probably due to saturation of favoured sites, since large numbers of unattached mites can be found in the leaf litter during this period.
Studies by light microscopy and scanning electron microscopy have shown that Bakerdania elliptica does not feed while attached to the cuticle of Oniscus asellus , and that all attached mites are females. Males are extremely rare and occur only in leaf litter. These observations suggest that the relationship between Bakerdania elliptica and Oniscus asellus is one of phoresy and that female mites use woodlice as an aid to dispersal during their life cycle.     

Efficacy of facemask resuscitation at birth.

The efficacy of facemask resuscitation was assessed by measuring the expiratory tidal volume during the first three inflations in nine babies with birth asphyxia and comparing the results with those obtained in a further nine babies resuscitated after endotracheal intubation. The facemask system was relatively inefficient, with tidal exchange less than one third of that seen after intubation and rarely sufficient to produce adequate alveolar ventilation. Successful resuscitation depended on stimulating the baby to make his own respiratory efforts.     

Variation in response to cytotoxicity of cigarette smoke.

The cytotoxic effect of cigarette smoke condensate on human polymorphs was investigated in vitro by the method of vital dye exclusion. Exposure to 1/800 of the smoke from one high-tar cigarette killed a detectable proportion of a population of 10(6) cells. The response among the cells from 40 healthy people varied widely, the percentage of dead cells ranging from 3% to 66% and from 17% to 87% at exposure levels of 125 micrograms and 250 micrograms cigarette smoke condensate respectively. Differences in individuals'' responses were reproducible and unrelated to age or sex or smoking habit. The cells from 10 patients with irreversible obstructive airways disease and probable emphysema were significantly more sensitive than those from 10 patients with no respiratory disability matched for age and smoking habits. Genetically influenced variation in cellular response to cytotoxicity may be an important determinant of the risk of developing emphysema among smokers.     

RhoJ modulates melanoma invasion by altering actin cytoskeletal dynamics

Rho family GTPases regulate diverse processes in human melanoma ranging from tumor formation to metastasis and chemoresistance. In this study, a combination of in vitro and in vivo approaches was utilized to determine whether RHOJ, a CDC42 homologue that regulates melanoma chemoresistance, also controls melanoma migration. Depletion or overexpression of RHOJ altered cellular morphology, implicating a role for RHOJ in modulating actin cytoskeletal dynamics. RHOJ depletion inhibited melanoma cell migration and invasion in vitro and melanoma tumor growth and lymphatic spread in mice. Molecular studies revealed that RHOJ alters actin cytoskeletal dynamics by inducing the phosphorylation of LIMK, cofilin, and p41‐ARC (ARP2/3 complex subunit) in a PAK1‐dependent manner in vitro and in tumor xenografts. Taken together, these observations identify RHOJ as a melanoma linchpin determinant that regulates both actin cytoskeletal dynamics and chemoresistance by activating PAK1.     

The status and conservation of the Cape Gannet Morus capensis

The Cape Gannet Morus capensis is one of several seabird species endemic to the Benguela upwelling ecosystem (BUS) but whose population has recently decreased, leading to an unfavourable IUCN Red List assessment. Application of ‘JARA’ (‘Just Another Red-List Assessment,’ a Bayesian state-space tool used for IUCN Red List assessments) to updated information on the areas occupied by Cape Gannets and the nest densities of breeding birds at their six colonies, suggested that the species should be classified as Vulnerable. However, the rate of decrease of Cape Gannets in their most-recent generation exceeded that of the previous generation, primarily as a result of large decreases at Bird Island, Lambert’s Bay, and Malgas Island, off South Africa’s west coast (the western part of their range). Since the 1960s, there has been an ongoing redistribution of the species from northwest to southeast around southern Africa, and ～70% of the population now occurs on the south coast of South Africa, at Bird Island in Algoa Bay, on the eastern border of the BUS. Recruitment rather than adult survival may be limiting the present population; however, information on the seabird’s demographic parameters and mortality in fisheries is lacking for colonies in the northern part of the BUS. Presently, major threats to Cape Gannet include: substantially decreased availability of their preferred prey in the west; heavy mortalities of eggs, chicks and fledglings at and around colonies, inflicted by Cape Fur Seals Arctocephalus pusillus and other seabirds; substantial disturbance at colonies caused by Cape Fur Seals attacking adult gannets ashore; oiling; and disease.