Bilateral rhomboid flaps for reconstruction of the external genitalia in epispadias-exstrophy

In ten young males with the epispadias-exstrophy complex, a new technique of bilateral rhomboid flaps was used for penile elongation and genital reconstruction. This approach offers less chance of injury to the verumontanum and ejaculatory ducts and accurately defines the penopubic angle. Cosmetic and functional results were satisfactory in all patients.     

Thermoregulatory physiology of the carpenter bee,Xylocopa varipuncta

Summary The carpenter beesXylocopa varipuncta maintain thoracic temperatures of 33.0°C to 46.5°C during continuous free flight from 12°C to 40°C. Since the thoracic temperature excess is not constant (decreasing from 24°C at low air temperatures to 6°C at high) the bees are thermoregulating. We document physiological transfer of relatively large amounts of heat to the abdomen and to the head during pre-flight warm-up and during artificial thoracic heating. Most of the temperature increase of the head is due to passive conduction, while that of the abdomen is due to active physiological heat transfer despite a series of convolutions of the aorta in the petiole that anatomically conform to a counter-current heat exchanger. Although the thermoregulatory mechanisms during flight are far from clarified, our data suggest that thermoregulation involves a strong reliance on active convective cooling through increased flight speed.     

Synthesis of an amplifiable reporter RNA for bioassays.

The replacement of reporter groups, such as fluorescent molecules or enzymes, by an amplifiable reporter should lead to bioassays of greatly increased sensitivity, since a very large number of copies of the reporter can be accumulated in a short time. Midivariant RNA is an appropriate reporter, since it is autocatalytically replicated by Q beta RNA polymerase in vitro. This RNA can be amplified exponentially, with a population doubling time of 36 seconds, resulting in the synthesis of 10(6) copies of each molecule in 12 minutes. We have used chemical methods to attach biotin to the 5' terminus of midivariant RNA via a disulfide linker. This biotinylated RNA combines with avidin to give a product that is readily purified by gel electrophoresis. The RNA-biotin-avidin adduct, and the RNA released from it by reductive cleavage of the linker arm, replicate normally. The RNA-biotin-avidin adduct should be a suitable reporter for a variety of replication-assisted bioassays involving biotinylated antibodies or biotinylated nucleic acid probes.     

Arachidonoyl transacylase in human platelets. Coenzyme A-independent transfer of arachidonate from phosphatidylcholine to lysoplasmenylethanolamine

Human platelets contain an enzyme that catalyzes CoA-independent release of arachidonic acid from phosphatidylcholine with concomitant incorporation into plasmenylethanolamine. Addition of lysoplasmenylethanolamine (10-80 microM) to a crude membrane preparation of prelabeled platelets (0.24 mg of protein/ml) induces transfer of [3H]arachidonate from endogenous phosphatidylcholine to lysoplasmenylethanolamine (0.8 nmol of arachidonic acid/min/mg of protein). The transacylation reaction occurs in the absence of Ca2+, has a broad pH optimum from 7 to 8, is not affected by excess unlabeled arachidonic acid, and is inhibited by N-ethylmaleimide (0.2 mM) and Triton X-100 (0.1 mg/ml). The enzyme shows a high specificity toward the acyl donor (phosphatidylcholine), transfers fatty acids in the order: arachidonic greater than eicosatrienoic greater than oleic, and preferentially acylates lysoplasmenylethanolamine but also other lysophosphatides (lysophosphatidylethanolamine greater than lysophosphatidylserine greater than lysophosphatidylinositol = 0). Platelet acyltransferase, on the other hand, acylates ethanolamine lysophosphatides with free arachidonic acid in the order: lysophosphatidyl-ethanolamine greater than lysoplasmenylethanolamine. These results suggest that a distinct acylation mechanism exists for introduction of arachidonic acid into plasmalogen phosphatides. In stimulated platelets, the transacylase may play an additional role in the controlled release of esterified arachidonic acid for synthesis of the biologically active oxygenated metabolites.     

Passive Avoidance Training Increases Fucokinase Activity in Right Forebrain Base of Day-Old Chicks

Fucokinase (EC 2.7.1.52) activity was estimated in supernatants of homogenate from day-old chick forebrain. Enzyme kinetic studies gave a Km of 4.5 X 10(-6) M and Vmax of 3.72 nmol fucose converted into fucose-1-phosphate/mg prot/h. The pH optimum was 7.5. The enzyme is thus considerably more active than was reported for other species and tissues. There were no differences in enzyme activity between the four forebrain regions studied. One hour after chicks were trained on a one-trial passive avoidance learning paradigm, enzyme activity in the right forebrain base increased 14% over control values (p less than 0.02). The 11.3% increase in activity in the left forebrain base and 10.3% increase in the left roof were not statistically significant. The relationship of this change to the increased fucose incorporation into glycoproteins known to occur over a similar time period and the significance of the lateralization of the increase are discussed.     

Irreversible Activation of the Opiate Receptor of Neuroblastoma × Glioma Hybrid Cells by an Alkylating Benzomorphan Derivative

The benozomorphan derivative (-)-2-[2-(p-bromoacetamidophenyl)ethyl]-5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphan (BAB), capable of reacting with nucleophilic groups, acts on neuroblastoma X glioma hybrid cells as a potent, irreversible opiate agonist. Its potency in inhibiting the increase in cellular cyclic AMP, evoked by prostaglandin E1, is comparable to that of Leu-enkephalin. This also applies to its capacity to compete with [3H]D-Ala2-Met-enkephalinamide ([3H]DAEA) in binding on cell membrane preparations. The comparatively lower potency of (-)-2-[2-(p-acetamidophenyl)-ethyl]-5,9 alpha-dimethly-2'-hydroxy-5,7-benzomorphan (AB), which differs from BAB in the substitution of the bromoacetamido group by an acetamido group, is of the same order of magnitude as that of morphine. The covalent interaction of BAB with the opiate receptors is deduced from the observations that (1) it is not possible to wash away this compound from the receptors, (2) the potency of BAB in inhibiting the specific binding of [3H]DAEA increases with prolonged preincubation time, and (3) AB behaves as a reversible agonist.     

Photolabile derivatives of bile salts. Synthesis and suitability for photoaffinity labeling

In an approach to the identification of bile salt-binding carriers, the photoactivable bile acid derivatives A) 3 beta-azido, 7 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oic acid, B) 7,7-azo-3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oic acid, and C) 11 xi-azido-12-oxo-3 alpha,7 alpha-dihydroxy-5 beta-cholan-24-oic acid were synthesized in unconjugated and taurine-conjugated form. Photolysis of the 3 beta-azido derivatives was studied using a light source with a maximum emission at 300 nm and established a half-life time of 18.5 min. The photochemistry of the 7,7-azo derivatives was investigated using light with a maximum at 350 nm and had a half-life time of 2.2 min. The 11 xi-azido-12-oxo derivatives were photolyzed with light having a maximum at 300 nm resulting in a half-life time of 8.5 min. The suitability of the 7,7-azo derivatives for photoaffinity labeling was demonstrated by photolyses in 14C-labeled methanol and acetonitrile. The generated carbene reacted with the solvents under covalent bond formation of 6 to 12%. The efficiency of all synthesized photolabile derivatives for photoaffinity labeling of bile salt binding proteins was demonstrated.     

Comparative analysis of the 5''-end regions of two repressible acid phosphatase genes in Saccharomyces cerevisiae.

The nucleotide sequence of 5'-noncoding and N-terminal coding regions of two coordinately regulated, repressible acid phosphatase genes from Saccharomyces cerevisiae were determined. These unlinked genes encode different, but structurally related polypeptides of molecular weights 60,000 and 56,000. The DNA sequences of their 5'-flanking regions show stretches of extensive homology upstream of, and surrounding, a "TATA" sequence and in a region in which heterogeneous 5' ends of the p60 mRNA were mapped. The predicted amino acid sequences encoded by the N-terminal regions of both genes were confirmed by determination of the amino acid sequence of the native exocellular acid phosphatase and the partial sequence of the presecretory polypeptide synthesized in a cell-free protein synthesizing system. The N-terminal region of the p60 polypeptide was shown to be characterized by a hydrophobic 17-amino acid signal polypeptide which is absent in the native exocellular protein and thought to be necessary for acid phosphatase secretion.