Effects of lung congestion and oleic acid injury on the Hering-Breuer reflex

Breathing and the Hering-Breuer (HB) reflex may be stimulated by congestion and by acute lung injury, but there is disagreement about the effects of both stimuli. This study evaluated these effects using greater stimulus isolation and control of secondary interactions than have previously been employed. Pressurization of lung vessels and left heart and oleic acid injury were individually imposed on anesthetized open-chest dogs perfused with an external pump and gas exchanger. Lungs were inflated in steps before and during those stimuli. The HB reflex was evaluated from graphs of breathing frequency (fr) vs. airway pressure. Congestion itself had no significant sustained effect on fr, but it slightly depressed the HB reflex. Oleic acid tachypnea that was depressed to pretreatment fr by inflation, implying enhancement of the HB response. Capsaicin and oleic acid had similar effects. Vagal cooling to 8 degrees C slightly depressed the effects of oleic acid and capsaicin, had no effect on the sustained fr response to congestion, and reversed the inhibitory effect of inflation. A stimulation of breathing or an enhancement of the HB reflex by congestion was not confirmed, but oleic acid increased fr and the HB reflex.     

High-frequency spontaneous deletion of DNA sequences flanked by direct DNA repeats which also contain an internal palindrome

The DNA sequences associated with a very high-frequency, spontaneous deletion event have been determined to be two 11-base direct repeats which also contain an internal 6-base palindrome. A parental M13 replicative form (RF) DNA harboring DNA fragments of the T4 denV gene contained these direct repeats and could only be maintained at 5% of the total RF DNA within an infected cell. The remaining RF DNA was deleted for all intervening sequences between the direct repeats (2.2-kb), but one copy of the direct repeat was retained after the deletion had occurred. This site-specific deletion was highly reproducible in that if parental-sized M13 RF DNA was gel purified and transformed back into cells, the deletion occurred at precisely the same sequence as before. Electron microscopic analyses of DNA extracted from cells transformed with parental-sized DNA revealed the presence of excised 2.2-kb double-stranded circular DNA molecules. This observation thus rules out a copy choice replication/deletion mechanism to account for this high-frequency deletion event.     

Biochemical analysis of two cell surface glycoprotein complexes, very common antigen 1 and very common antigen 2. Relationship to very late activation T cell antigens

Two mouse monoclonal antibodies (mAb), AJ2 and J143, define two related human cell surface protein complexes, very common antigen 1 (VCA-1) and very common antigen 2 (VCA-2). In the present report, these complexes have been defined with respect to: (i) subunit arrangement; (ii) monoclonal antibody binding sites; (iii) carbohydrate content; (iv) homology to other cell surface protein complexes; and (v) possible functional roles. Analysis of the antigens from a human melanoma cell line, MeWo, reveals that VCA-1 is a noncovalently linked heterodimer of 170- and 140 (designated 1401)-kDa polypeptides. mAb AJ2 reacts with an epitope on the 1401-kDa polypeptide. VCA-2 is composed of the same 1401-kDa polypeptide as VCA-1 and another 170-kDa species; this 170-kDa species consists of a second distinct 140-kDa (designated 140(2)) and a 30-kDa polypeptide which are disulfide-bonded. Indirect evidence indicates that mAb J143 reacts with an epitope on this 170-kDa complex. Peptide mapping has shown that the complexes are members of a family of cell surface proteins that include antigens present on activated T cells (designated very late activation antigens). Since VCA-2 is found predominantly on the basal membrane of adherent cells and its expression increases 12-fold when HUT-102 lymphoblastoid cells are grown as an adherent cell culture, we suggest that VCA-2 plays a role in cellular adherence.     

Detection of luteinizing hormone beta messenger ribonucleic acid (RNA) in individual gonadotropes after castration: use of a new in situ hybridization method with a photobiotinylated complementary RNA probe

Patterns of gonadotropin storage in individual gonadotropes change with alterations in the physiological state. After castration in the male rat, there is a 2.5-fold increase in the percentage of gonadotropes and an increase in the proportion of gonadotropes storing both LH and FSH. In addition, there are 6- to 8-fold increases in the pituitary concentrations of LH beta subunit mRNAs. In order to determine whether these changes are due to increases in the number of gonadotropes containing subunit mRNA, or the amount of mRNA per cell or both, an in situ hybridization technique using a photobiotinylated rat LH beta cRNA probe (bio-LH beta-cRNA) was applied to detect LH beta mRNA in fixed whole rat pituitary cells from intact or castrated rats. After hybridization, the bio-LH beta-cRNA was localized with either avidin-biotin peroxidase complex or the fluorescent streptavidin phycoprobe methods. The cells containing LH beta mRNA were then counted and the amount of mRNA per cell was measured by video microdensitometry. Ten percent of the anterior pituitary cells from intact animals contained LH beta mRNA. After castration (2-4 weeks) this percentage rose to 19-24.5%. Image and microdensitometric analyses showed that castration produced a 1.9-fold increase in the amount of LH beta mRNA per cell, and a 2.2-fold increase in the area of cells containing LH beta mRNA. Hence, castration resulted in an increase in the level of LH beta mRNA per cell as well as the number of LH beta mRNA-containing cells. When in situ hybridization was followed by immunocytochemistry in cells from intact rats, 83% of gonadotropes that stained for LH beta and 80% of gonadotropes that stained for FSH beta contained LH beta mRNA whereas after castration 99% of LH-storing and 93% of FSH-storing cells contained LH beta mRNA. This new in situ hybridization protocol is rapid and allows quantification of mRNA within individual gonadotropes. In addition, since the hybridization protocol does not apparently alter the gonadotropin antigens, the hormone content of the same gonadotrope may be defined by immunocytochemistry.     

The effects of decreased growth temperature on the cystine content of cystinotic fibroblasts

Cystinotic fibroblasts transferred from 37 degrees C to 28 degrees C accumulated additional cystine over the period from 4 to 7 days of incubation at 28 degrees C, after which the additional cystine was lost; warming (to 37 degrees C) of cells with elevated cystine stores led to rapid cystine loss. These results, taken together with previously published data showing cystine release from cystinotic fibroblasts incubated at above-normal temperature, are interpreted as indicating the presence in the cystinotic fibroblast lysosome membrane of a cystine-porter whose efficacy is increased by an increase in membrane fluidity. This porter may be the residual activity of the cystine porter that is known to be deficient in cystinosis, or it may be a second as yet unrecognized porter. It is further proposed that this porter is responsible for the presumed efflux of cystine from cystinotic lysosomes.     

Effects of male partners upon proceptivity in ovariectomized estradiol-treated marmosets (Callithrix jacchus)

Effects of male partners upon the expression of female proceptivity were examined in two experiments using 16 ovariectomized marmosets. Experiment 1 showed that the female's proceptive tongue-flicking display (PTF) is triggered specifically by eye contact with the male. Stimulation of PTF by administration of estradiol-17 beta (E2) to ovariectomized females depends in part upon the male's responsiveness to female displays, such as "staring" and "freezing," which may serve to attract his attention and to establish eye contact. Experiment 2 provided evidence that females' proceptivity decreases if their male partners are lesioned in the preoptic area/anterior hypothalamus. Such males are sexually hypoactive and less responsive to the females' visual displays. However, E2 still activates PTF if females succeed in initiating eye contact with males. Results indicate that variability in effects of E2 upon proceptivity in marmosets may be influenced by subtle aspects of facial communication between the sexes as well as by individual differences in hormonal sensitivity. Copulatory activity in males is not essential for E2 to exert its stimulatory action upon proceptivity in female marmosets.     

Identification of N-glycolylneuraminic acid-containing gangliosides of cat and sheep erythrocytes. 252Cf fission fragment ionization mass spectrometry in the analysis of glycosphingolipids

A number of gangliosides were isolated from cat and sheep erythrocytes for use in analyzing the specificity of a panel of human anti-heterophile monoclonal antibodies. The structures of these compounds were determined by a combination of different procedures, including sugar analysis, glycosidase treatment, periodate oxidation, TLC immunostaining, methylation analysis, and mass spectrometry. These methods identified the cat erythrocytes gangliosides (C1 and C2) as N-glycolylneuraminic acid (NeuGc)-containing hematosides; C1 was shown to be NeuGc alpha 2----8NeuGc alpha 2----3Gal beta I----4Glc-Cer [NeuGc)2GD3) and C2 to be NeuAc alpha 2----8NeuGc alpha 2----3Gal beta 1----4Glc-Cer [NeuAc-NeuGc-)GD3). The two sheep gangliosides (S1 and S2) were found to be novel glycolipids based on the paragloboside sequence; S1 was identified as NeuGc alpha 2----8NeuGc alpha 2----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc-Cer [NeuGc)2-disialylparagloboside) and S2 as NeuAc alpha 2----8NeuGc alpha 2----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc-Cer [NeuAc-NeuGc-)-disialylparagloboside). Structural analysis of these compounds was aided by the use of 252Cf fission fragment ionization time-of-flight mass spectrometry. This method provided easily interpretable spectra on methylated derivatives which were particularly useful in determining the sialic acid composition of the gangliosides and the sequence of their disialosyl side chains.     

A single base mutation in the gene for type III collagen (COL3A1) converts glycine 847 to glutamic acid in a family with Ehlers-Danlos syndrome type IV. An unaffected family member is mosaic for the mutation

Summary Ehlers-Danlos syndrome type IV, an inherited connective tissue disease, is usually caused by mutations in the gene for type III collagen. Here, we describe a glycine to glutamic acid substitution in a patient with this syndrome. Previous studies had shown that fibroblasts from the patient, his mother and brother secreted a reduced amount of type III collagen and also produced an overmodified form of the protein that was preferentially retained intracellularly. Peptide mapping experiments indicated that the mutation was located within cyanogen bromide peptide 9. This was supported by chemical cleavage analysis and sequencing of cDNA encoding this region. Allele-specific oligonucleotide hybridisation of genomic DNA confirmed that a G to A mutation converted Gly 847 to Glu. The mutation was present in two other affected family members and also in a third, who was clinically unaffected. Further analysis of this unaffected individual revealed reduced mutant:normal ratios in DNA obtained from both blood and hair samples, showing that she was mosaic for the mutation.     

Demographic responses of arctic hares Lepus arcticus placed on two predominantly forested islands in Newfoundland

During January-April 1989. we monitored survival, reproduction, and body condition of 19 radio-collared arctic hares Lepus areticus introduced to two predominantly (80%) forested islands. Merchant (66 1 ha) and Burke (82 6 ha), in Placentia Bay, Newfoundland By late April, bone-marrow fat (42 7%) and kidney fat indices were lower than found in populations on the mountain barrens of western Newfoundland However, most island hares gained weight overwinter, and litter sizes (mean. 4 2 in utero) and testis weights (mean, 8 3 g) were as large or larger than recorded from other introduced and natural populations in Newfoundland The distribution of telemetry locations, tracks and feeding sites indicated that hares frequented the scattered barrens (totalling c 30 ha) on both islands in greater proportion than available These results suggest that, in the absence of snowshoe hares and mammalian predators, forested regions interspersed with small patches of barrens can sustain arctic hares