Lung Function in Patients Receiving Busulphan

An attempt was made to achieve earlier detection of busulphan lung (fibrosing alveolitis) and to determine its incidence by means of serial studies during life, including measurement of the gas transfer factor. Twenty-three patients were investigated over an average period of nearly two years of busulphan treatment. One case of busulphan lung was detected and subsequently confirmed at necropsy, but in the remainder there was no clinical, radiological, or physiological evidence of fibrosing alveolitis. It is concluded that the development of fibrosing alveolitis may be related to individual genetic or immunological factors rather than to busulphan dosage.     

Escapes from herbivory in relation to the structure of mangrove island macroalgal communities

Summary Some shallow habitats that surround mangrove islands exhibit abruptly discontinuous macrophyte boundaries; in other regions, plant distributional patterns are less defined. Where distinct boundaries do occur, fleshy algae predominate on the roots of the red mangrove, Rhizophora mangle, which do not contact the bottom sediments (hanging roots), while calcifying algae dominate on the substratum-penetrating roots and banks (=embedded-root habitat) surrounding the mangrove thickets. Considerable natural-history and floristic information reveals that the fleshy hanging-root species are not specialists, for that type of habitat. Experimental transplants showed that on banks and embedded roots where there typically are abundant macroherbivores (particularly sea urchins), most fleshy algae are eliminated.The dominants of the hanging-root habitat (e.g, Acanthophora spicifera, Spyridia filamentosa, Caulerpa racemosa var. Occidentalis) are 6–20 times more susceptible to herbivores than the dominants of the embedded-root habitat (e.g., Halimeda opuntia f. triloba, H. monile). Consequently, we suggest the former are relegated to the spatial refugia from herbivores (=non-coexistence escapes) provided by the hanging roots. Factors associated with these palatability differences include higher average calorific values (6.5 times) of the fleshy hanging-root dominants, greater proportions of organic content (2.6 times) and the general absence of calcification. The dominants of the embedded-root habitat show reduced edibility as a probable consequence of low calorific values, heavy calcification and potential herbivore-detering secondary metabolites. Correlative evidence and preliminary experimental results tentatively indicate that, in the absence of macroherbivores, the hanging-root dominants, which exhibit production rates 4.7 times greater than the dominants of the embedded-root habitat, are better competitors for space.We suggest that variations in herbivory are responsible, in part, for maintaining greater algal diversity in mangrove systems. At a study site with abundant sea urchins, five algal species were found only in the embedded-root habitat three species were confined to the hanging roots, while three others occurred in both. At an urchin-free site, no macrophytes were found only on embedded-root substrata, while one (in trace amounts) was found only on hanging-root habitat and eight occurred in both. We predict that in the absence of herbivores, the species assemblage characteristic of the hanging-roots would exclude many of the dominants from the embedded-root habitat.     

Identification of an Epstein-Barr virus-coded thymidine kinase.

We have demonstrated the presence of an Epstein-Barr virus (EBV)-coded thymidine kinase (TK) by producing biochemically transformed, TK-positive mammalian cell lines using either microinjection of whole EBV virions or calcium phosphate-mediated transfection of the SalI-B restriction endonuclease fragment of EBV DNA. Analysis of these cell lines showed that: (i) EBV DNA was present in the cell lines, (ii) sequences from the SalI-B restriction endonuclease fragment of EBV were expressed, (iii) a TK activity was present and (iv) a protein with antigenic cross-reactivity with the herpes simplex virus (HSV) TK was produced. The identity of the EBV TK gene was determined by demonstrating that a recombinant plasmid, which expressed the protein product of the BXLF1 open reading frame as a fusion protein, could complement TK- strains of E. coli. A comparison of the predicted amino acid sequences of the TK proteins of EBV and HSV-1 revealed significant regions of homology.     

Identification, cloning, and expression of the major capsid protein gene of human herpesvirus 6.

DNA sequence analysis of part of the human herpesvirus 6 (HHV-6) genome led to the identification of an open reading frame with amino acid sequence homology to the major capsid proteins (MCP) of other HHVs. DIAGON analysis showed that the closest homology was with human cytomegalovirus. Plasmids were constructed which were shown to express the HHV-6 MCP as either the entire open reading frame or as portions of it, and the recombinant-produced proteins were used to raise antisera. The antisera were shown by immunofluorescence to react with HHV-6-infected lymphoblastoid cells and in Western blots with a 135-kilodalton protein specific to HHV-6-infected cells. The recombinant protein expressed from the entire HHV-6 MCP gene was detected only weakly in Western blot assays with normal HHV-6-positive human sera as a probe.     

A comparison of nutrient- and light-limited photosynthesis in psammophytic versus epilithic forms of Halimeda (Caulerpales,Halimedaceae) from the Bahamas

The relative nutritional status, with respect to phosphorus (P _i ) vs. nitrogen (N) limitation, and light-limited photosynthesis (P _s ) was examined over a broad range of quantum fluxes (I) for four Halimeda species, Halimeda tuna (Ellis and Solander) Lamouroux, H. simulans Howe, H. lacrimosa Howe and H. copiosa Goreau and Graham, taken from clear, shallow, Bahamian waters. The results support the hypothesis that psammophytic forms (i.e., sand dwellers anchored by a bulbous rhizoidal system) differ in nutrient status from epilithic forms (i.e., attached to rock by inconspicuous rhizoids). Maximum photosynthetic rates (P _max) for the epilithic species H. lacrimos and H. copiosa decreased (P<0.05) following P _i enrichment, but increased (P<0.05) following N pulses. Conversely, following brief exposures to P _i , P _max in the sand-dwelling forms H. tuna and H. simulans was elevated (P<0.05). These findings suggest that shallow species of Halimeda are adapted to take advantage of episodic nutrient pulses, and that partitioning of limiting resources may occur between the various life forms. Shallow water Halimeda species appear well adapted to variable light regimes, including low light conditions. In all cases, light-saturated photosyntheses (I _k ) occurred at irradiances much lower than the ambient levels available on typical sunny days. Associated with low saturation irradiances were low light requirements for photosynthetic compensation (I _c ) and reasonably efficient use of low photon flux densities as indicated by relatively steep slopes () of the P _s vs. I curves. Of the four species, H. copiosa was the most shade adapted, with considerably higher values and considerably lower I _c , I _k and photoinhibition values.     

Comparative phosphate acquisition in giant-celled rhizophytic algae (Bryopsidales, Chlorophyta): Fleshy vs. calcified forms

Phosphate uptake through above-ground thalli vs. subterranean rhizoids has been compared in siphonaceous rhizophytic green algal species from five globally distributed tropical genera: Avrainvillea nigricans Decaisne, Caulerpa lanuginosa J. Agardh, Halimeda incrassata (J. Ellis) J.V. Lamouroux, Penicillus capitatus Lamarck, and Udotea flabellum (J. Ellis & Solander) M. Howe. Plants were collected, acclimated to lab conditions for 3 days, and then incubated for 8 h at saturating light intensity with 30 μM PO₄³⁻ added to their above-ground thallus or below-ground rhizoids. Percent tissue phosphorus was then compared to control specimens, which were run simultaneously in the absence of phosphate. The two fleshy species, A. nigricans and C. lanuginosa, showed no significant differences in tissue nutrient status, and displayed much larger variation among controls than the three calcified species. Calcified species showed greater phosphorus content after being exposed to either above- or below-ground thallus portions, indicating that these seaweeds can respond to short term increases in nutrient availability and have a more regulated nutrient acquisition mechanism. Results suggest that calcification may play an important role in phosphorus absorption.