SUCCESSFUL SURGICAL MANAGEMENT OF CONGENITAL ARTERIOVENOUS FISTULA OF THE SUBCLAVIAN ARTERY: CASE REPORT

A 10-month-old infant was found to have an isolated congenital arteriovenous fistula between the right subclavian artery and vein. Ligation of the fistula resulted in complete anatomic correction and rapid resolution of cardiomegaly.     

Partial characterization of a soluble ATPase from pea cotyledon mitochondria.

A partially purified soluble ATPase (ATP phosphohydrolase, EC 3.6.1.3) from pea cotyledon mitochondria was characterized. Inhibition patterns with azide, NaF, and cold, and a stimulation by 2,4-dinitrophenol were typical of F1-ATPases from mammalian mitochondria. The enzyme hydrolysed GTP, ITP, and ATP, but not CTP, UTP, ADP, or IDP. ATPase and ITPase activities were strongly inhibited by ADP and to a lesser extent by IDP. Distinctive properties of the pea mitochondrial enzyme were activation by high concentrations of CaCl2 and stimulation by NaCl.     

Sweat tests to diagnose cystic fibrosis in adults.

Twenty five patients with cystic fibrosis and 25 controls were studied to define a sweat sodium concentration in adults that could be taken as diagnostic of cystic fibrosis. Some of the controls had a sweat sodium concentration of over 50 mmol(mEq)/l, and thus cystic fibrosis should be diagnosed in an adult only when two measurements of sweat sodium concentration are above 70 mmol/l. In cases in which the sweat sodium concentration was borderline a suppression test using fludrocortisone improved the accuracy of diagnosis; this test entails recording the lowest concentration reached after administration of the drug. A scatter diagram of the baseline sweat sodium concentrations plotted against the lowest concentration attained after suppression with fludrocortisone may aid the diagnosis further.     

Glucocorticoid modulation of lymphokine-induced macrophage proliferation

The ability of glucocorticoids to modify lymphokine-induced macrophage proliferation, an in vitro correlate of cellular immunity in the guinea pig, was investigated. Lymphocyte production of macrophage mitogenic factor (MMF) was decreased in the presence of physiological concentrations of glucocorticoids. Inhibition was concentration dependent (IC₅₀ of triamcinolone acetonide (TA): 2 × 10^?9M), glucocorticoid specific, and reversed by cortexolone. In contrast, pharmacological concentrations of glucocorticoids were necessary to inhibit macrophage proliferation induced by suboptimal dilutions of MMF. This inhibition was concentration dependent (IC₅₀ of TA: 4 × 10^?7M), glucocorticoid specific, and reversed by cortexolone. At supraoptimal dilutions of MMF, glucocorticoids caused a twofold potentiation of MMF-induced macrophage proliferation. Potentiation was concentration dependent (EC₅₀ of TA: 3 × 10^?8M), glucocorticoid specific, reversed by glucocorticoid antagonists, and occurred in the presence of indomethacin. Thus, glucocorticoids regulate both the initiation and effector phases of this in vitro model of delayed hypersensitivity. However, the results indicate that the major mechanism of glucocorticoid-mediated anti-inflammatory action occurs at the level of the MMF-producing lymphocyte rather than at the effector macrophage, as MMF-induced proliferation is likely controlled by opposing glucocorticoid-sensitive mechanisms.     

IL-1 gene expression in lymphoid tissues

We examined the expression of IL-1 mRNA in vivo by in situ hybridization. RNA probes for murine IL-1 alpha and IL-1 beta were used to detect IL-1 mRNA in frozen sections of spleen, lymph node, and thymus of mice injected with Salmonella typhi LPS or SRBC. No IL-1 was detected in lymphoid tissues from un-injected mice. This lack of expression correlated with the absence of IL-1 biologic activity. However, after LPS injection, IL-1 alpha and beta mRNA expression was found in macrophages of the red pulp and marginal zone of the spleen. The periarteriolar lymphoid sheath contained cells that only expressed IL-1 beta mRNA. These cells were not lymphocytes and did not stain with the macrophage marker F4/80. A similar cellular response was found after SRBC injection. Scattered macrophages in lymph nodes and thymus were positive, but only after LPS or SRBC injection. The spleens of mice injected with LPS had megakaryocytes containing IL-1 mRNA.     

Prevention of fungal colonization and digestion of cellulose by the addition of methylcellulose

When the attachment of cellulolytic rumen fungi to cellulose is blocked by the addition of methylcellulose, cellulose digestion is entirely inhibited. Even after these fungi have colonized and penetrated the cellulosic fibers of filter paper, the addition of methylcellulose effectively halts cellulose digestion. This effect of methylcellulose is accompanied by the complete inhibition of fungal attachment to cellulose fibers; the addition of methylcellulose does not affect the growth of these organisms on soluble substrates. We conclude that fungal cellulose digestion, like bacterial cellulose digestion, requires the spatial juxtaposition of the cellulolytic organism and its insoluble substrate. The simultaneous inhibition of both attachment and digestion by the same inhibitor suggests that these two processes are functionally linked in the fungi.     

Molecular cloning and characterization of (R)-3-hydroxybutyrate dehydrogenase from human heart.

The complete amino acid sequence of human heart (R)-3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) has been deduced from the nucleotide sequence of cDNA clones. This mitochondrial enzyme has an absolute and specific requirement of phosphatidylcholine for enzymic activity (allosteric activator) and is an important prototype of lipid-requiring enzymes. Despite extensive studies, the primary sequence has not been available and is now reported. The mature form of the enzyme consists of 297 amino acids (predicted M(r) of 33,117), does not appear to contain any transmembrane helices, and is homologous with the family of short-chain alcohol dehydrogenases (SC-ADH) (Persson, B., Krook, M., and J?rnvall, H. (1991) Eur. J. Biochem. 200, 537-543) (30% residue identity with human 17 beta-hydroxysteroid dehydrogenase). The first two-thirds of the enzyme includes both putative coenzyme binding and active site conserved residues and exhibits a predicted secondary structure motif (alternating alpha-helices and beta-sheet) characteristic of SC-ADH. Bovine heart peptide sequences (174 residues in nine sequences determined by microsequencing) have extensive homology (89% identical residues) with the deduced human heart sequence. The C-terminal third (Asn-194 to Arg-297) shows little sequence homology with the SC-ADH and likely contains elements that determine the substrate specificity for the enzyme including the phospholipid (phosphatidylcholine) binding site(s). Northern blot analysis identifies a 1.3-kilobase mRNA encoding the enzyme in heart tissue.     

Polymorphic analysis of the three MHC-linked HSP70 genes

Three genes encoding members of the M _r 70 000 heat shock protein family (HSP70) are known to lie in the class III region of the human major histocompatibility complex. IN order to determine whether these genes or their protein products exhibit any polymorphism the three genes have been specifically amplified from genomic DNA and sequenced. The HSP70-1 and HSP70-2 genes encode the major heat-inducible HSP70. A comparison of the nucleotide sequences of these genes from B8, SC01, DR3, B18, F1C30, DR3, and B7, SC30, DR2 haplotypes has revelad only very limited sequence variation which is not associated with any amino acid polymorphism. The HSP70-Hom gene encodes a protein that is highly related to HSP70-1, but which is not heat-inducible. Nucleotide sequence analysis of this gene from different haplotypes has revealed a Met Thr amino acid substitution at residue 493 in a number of the haplotypes tested. This variable amino acid lies in the proposed peptide-binding site of the HSP70-Hom protein. Address correspondence and offprint requests to: R. D. Campbell.     

The production and ingestion of faecal pellets by nauplii of marine calanoid copepods

The downward transport of organic matter as zooplankton faecalmaterial is influenced by copepods which fragment, ingest andrecycle some of the pellet contents. Most of this activity hasbeen attributed to the later copepodite stages and the adults,but little is known about the role of nauplii. Stage-relateddefaecation rates during the naupliar development of two speciesof copepod, Calanus helgolandicus and Pseudocalanus elongatus,were quantified in a series of laboratory experiments. The productionof faecal material commenced soon after the appearance of theNIII in both species and increased throughout naupliar development.The causes of the increase were the formation of larger pelletsby later stages in Calanus and an increased rate of productionby Pseudocalanus. Calanus nauplii, when supplied with algalfood at concentrations that would support full naupliar development,ingested or broke up the pellets of the smaller Pseudocalanusspecies at rates of 1.15 pellets nauplius^–1 h^–1This consumption increased to 2.96 pellets nauplius^–1h^–1 when the concentration of algal food was reduced toa limiting level. Pseudocalanus was not able to consume thepellets of Calanus. Ingestion of Pseudocalanus faecal pelletsby Calanus could supply a nutritional benefit to a food-limitednauplius.