Aqueous-phase photochemical formation of peroxides in authentic cloud and fog waters

Gas-to-drop partitioning of hydrogen peroxide and its precursor, the hydroperoxyl radical (HO2.), has been considered the predominant or sole source of hydrogen peroxide in atmospheric water drops. However, atmospheric water can absorb solar ultraviolet radiation, which initiates the photoformation of peroxides (primarily hydrogen peroxide). Measurements of peroxide photoformation rates in authentic atmospheric water samples demonstrate that aqueous-phase photochemical reactions are a significant, and in some cases dominant, source of hydrogen peroxide to cloud and fog drops. This additional source could significantly change the current understanding, and hence, the models, of sulfuric acid deposition because hydrogen peroxide is the limiting reagent in the dominant pathway for the oxidation of sulfur dioxide to sulfuric acid in the troposphere over eastern North America.

Depressive symptoms and family history in seasonal and nonseasonal mood disorders

OBJECTIVE

The authors' goal was to compare the symptoms and family history of seasonal affective disorder with those of nonseasonal mood disorders.

METHOD

From a subspecialty mood disorders clinic, 34 patients with major depression, seasonal pattern (seasonal affective disorder), diagnosed with DSM-III-R criteria, were matched in age, sex, and diagnostic subtype (recurrent unipolar, bipolar I, or bipolar II) to 34 patients with nonseasonal mood disorders. Data on symptoms during the most recent depressive episode were obtained by chart review and compared by using chi-square tests. Family history data for first-degree relatives of patients with seasonal and nonseasonal mood disorders were gathered by using the family history method, and diagnoses were based on Family History Research Diagnostic Criteria.

RESULTS

Patients with seasonal affective disorder reported significantly more hypersomnia, hyperphagia, and weight gain and reported less suicidal ideation and morning worsening of mood than the patients with nonseasonal mood disorders. No differences were found in family histories of mood disorders, other psychiatric disorders, and any psychiatric disorder between the groups with seasonal versus nonseasonal mood disorders. Alcoholism was found more frequently in the relatives of the patients with seasonal affective disorder.

CONCLUSIONS

Differences in symptoms between seasonal and nonseasonal mood disorders provide some support for seasonal affective disorder as a diagnostic subtype of mood disorders. However, the genetic loading for mood disorders (of unspecified seasonality), as determined by the family history method, is similar for seasonal and nonseasonal mood disorders.

Identification of a neuron-specific promoter of human aromatic L-amino acid decarboxylase gene

We have cloned the 5' region of human aromatic L-amino acid decarboxylase (AADC) gene in a cosmid and an overlapping lambda clone, and sequenced the first five exons. A 61 base pair (bp) non-coding, first exon containing for the 5' end of a human pheochromocytoma AADC cDNA was localized 16 kb upstream of exon 2, in which translation is initiated. The transcription start site was localized by RNAse mapping, primer extension and reverse transcription-PCR. The non-conventional cap site was preceded by a modified TATA box at position -29. A strong promoter was characterized in the 560 bp region upstream of the cap site by linkage to the reporter gene LacZ, and transfection in human neuroblastoma SK-N-BE and SK-N-BE-K2 cells. Using a series of constructs bearing a varying length of 5' flanking region, three positive regulatory elements have been localized in the -560 to -394, -244 to -200 and -147 to -1 regions. Negative regulatory elements were localized in the -9000 to -560 and -394 to -316 regions. Surprisingly, constructs comprising all or the major part of intron 1 were inactive, suggesting the presence of a silencer in the first intron, or incorrect splicing events. The construct containing 560 bp of 5' flanking sequence did not express in human cholinergic neuroepithelioma cells MC-I-XC, and in three non-neuronal cell lines which displayed high AADC activities: human pancreatic carcinoma cells AsPC-1, rat insulinoma cells RINm5F and mouse anterior pituitary cells AtT20. These data suggest that we have identified a neuron-specific AADC promoter. An extensive search for a second promoter responsible for AADC gene expression in non-neuronal cells only gave negative results.

Functional dissection of the lck proximal promoter

The lck gene encodes a protein tyrosine kinase that participates in lymphocyte-specific signal transduction pathways. Previous studies have established that lck transcription is regulated by two distinct promoter elements termed proximal (or 3') and distal (or 5'). The proximal promoter is active almost exclusively in thymocytes and becomes inactive later during T-cell maturation. To dissect the mechanisms responsible for lck gene regulation, we generated transgenic animals bearing 5' truncations in the proximal promoter element. Sequences between -584 and +37 with respect to the proximal promoter transcription start site act to direct tissue-specific and temporally correct transcription of either a tagged version of the lck gene itself or a heterologous reporter sequence (lacZ). This region contains binding sites for at least five distinct nuclear proteins, of which one is found only in cells that support proximal lck promoter activity and a second appears only in nonexpressing cells. Interestingly, the transcribed region of the lck gene contains positive control elements that can substantially boost expression from minimal (-130 bp) proximal promoter constructs. These results provide a basis for the biochemical dissection of transcriptional regulators that act at defined points during T-cell development.

Decreased beta 2-adrenergic receptor mRNA expression in receptor-deficient S49 lymphoma cells

Many variants of the S49 mouse lymphoma cell have been isolated along the pathway of cyclic AMP generation and response. Two such variants, beta p and beta d, were isolated by Johnson and colleagues and described in 1979 [Mol. Pharmacol. 15:16-27 (1979)]. The beta p and beta d variants express one half and one quarter, respectively, of the wild-type number of beta 2-adrenergic receptors. This observation has now been extended through the use of DNA-excess solution hybridization. Using this exquisitely sensitive technique for quantitation of gene and mRNA, we have been able to demonstrate that the beta 2-adrenergic receptor-deficient variant cells contain the same quantity of the beta 2-adrenergic receptor gene as the wild-type cells. In contrast, the beta 2-adrenergic receptor-deficient variant cells express reduced quantities of beta 2-adrenergic receptor-specific mRNA. The amount of beta 2-adrenergic receptor-specific mRNA correlates very well with the reduction in receptor expression in these cells. Both gene and mRNA in the wild-type and variant cells appear to be the same size, as judged by Southern and Northern analysis. Thus, the diminution of beta 2-adrenergic receptors in the beta p and beta d variants appears to reflect primarily the relative paucity of gene transcripts in the variant cells. These data imply that variations in cellular content of beta 2-adrenergic receptor mRNA, which may occur among closely related cells, is one explanation for differences in receptor number.

Effects of some neurokinin A analogues on tachykinin-induced contraction of guinea pig trachea

A series of analogues of neurokinin A (NKA) has been synthesized and characterized by testing for their abilities, in vitro, to contract guinea pig tracheal smooth muscle or to antagonize NKA-, NKB- and SP-induced contraction of this tissue. Substitution of NKA residues Gly8 or Leu9 by conformationally restricting amino acids produced peptides that were antagonists of NKA action, but the type and specificity of the antagonism depended on the size of the peptide. Thus, while [Ala5, Aib8, Leu10]NKA(2-10) showed no agonism and was a specific, competitive antagonist of NKA, [Ala5, Aib8, Leu10]NKA(4-10) was a noncompetitive antagonist of NKA and substance P (SP) and was itself a weak agonist at concentrations above 10(-7) M.

Developmental regulation of lck gene expression in T lymphocytes

In the mouse and human, mRNA transcripts encoding the lymphocyte-specific protein tyrosine kinase p56lck are derived from two separate promoters resulting in heterogeneity in the 5' untranslated region sequence. The proximal promoter lies just 5' to the coding region for the gene and is active only in thymocytes. In contrast, the distal promoter lies 34 kilobases (kb) 5' in the human, and is active both in thymocytes and mature peripheral T cells. As previously reported, transgenic mice bearing functional proximal promoter sequence juxtaposed with the SV40 large T antigen gene invariably develop lymphoid tumors confined to the thymus. In the current work, transgenic mice bearing a 2.6-kb fragment of the human distal promoter fused to the SV40 large T antigen gene express large T antigen in thymocytes and in peripheral lymphoid cells, and develop tumors of both the thymus and the peripheral lymphoid organs. The ability of the human distal promoter to function appropriately in transgenic mice is consistent with the strong similarity observed between the mouse and human distal promoter sequences. With the exception of a single short interval that serves as a target for binding of nuclear factors, significant sequence similarity is not seen when the distal and proximal promoter sequences are compared. Hence, developmentally regulated, lineage-specific transcription of the lck gene is mediated by distinct promoter sequences that appear to be capable of functioning independently.

Molecular structure of neuropeptide Y

The original description of NPY following its isolation commented on its homology to the pancreatic polypeptide family of peptides. This homology is extended to the mRNA sequences and the genomic structure, suggesting that this family has arisen as a result of gene duplication. However, each member demonstrates remarkable specificity in its expression within tissue types. The expression of the NPY gene is thus controlled by, as yet undefined, factors regulating to neural cells. The level of expression within cells is dependent on nerve growth factor. However, other factors, such as the rate of processing of the precursor, may be involved in regulation of the stored concentrations of the peptide product.

Nerve-mediated contractions of sheep mesenteric lymph node capsules

1. Isometric tension was recorded in vitro from strips cut from the capsules of mesenteric lymph nodes of sheep. 2. One minute periods of field stimulation at frequencies of 1, 2, 4, 8 and 16 Hz (pulse duration, 0.3 ms) elicited tonic contractions of increasing force and duration. The stimulus frequency-response relationship began to flatten out at frequencies greater than 4 Hz, where the response was already 72% of that at 16 Hz. 3. The response to field stimulation was abolished by tetrodotoxin (1 microM). 4. Phentolamine, rauwolscine and prazosin (all 1 microM) reduced the response to field stimulation, while desipramine (1 microM), potentiated it. 5. Atropine (1 microM) was without effect on the response. 6. These results suggest that sheep mesenteric lymph node capsules have a noradrenergic innervation which modulates their tone via an action on alpha-adrenoceptors.

Neuropeptide Y (NPY)-containing nerves in mammalian ureter

The distribution of neuropeptide Y in the ureter of the rat, rabbit, and man has been determined by radioimmunoassay and chromatographic analysis of the tissue extract. The localization of neuropeptide Y-immunoreactivity has been identified by immunocytochemistry. A regional distribution of neuropeptide Y was found; highest concentrations being present in the ureterovesical junction. Throughout the ureter, neuropeptide Y-immunoreactive nerve fibers were identified to surround the blood vessels and a few plexuses of neuropeptide Y-containing nerves were present within the muscle layers. Neuropeptide Y was not present within ganglion cells. Treatment of rats with 6-hydroxydopamine resulted in a significant reduction of neuropeptide Y concentrations in the upper, middle, and lower thirds of the ureter. This depletion in extractable neuropeptide Y was associated with morphologic changes typical of axonal degeneration of the neuropeptide Y-containing nerve fibers.

Sex differences in vasoactive intestinal peptide (VIP) concentrations in the anterior pituitary and hypothalamus of rats

Recent evidence suggests that vasoactive intestinal peptide (VIP), a putative prolactin (PRL)-releasing factor, is both synthesized and released by anterior pituitary cells, to act as a paracrine or autocrine factor. We have investigated the hypothesis that hypothalamic or pituitary VIP levels differ in male and female rats, since neuroendocrine control of PRL is sexually differentiated. Opposite sex differences were found in the hypothalamus and anterior pituitary. Random-cycle female rats had one-third higher VIP levels in the hypothalamus than males. In contrast, anterior pituitary VIP levels were 3 times as high in male rats as in females. Median eminence VIP levels were similarly low in both sexes. These results support a possible role of VIP in the sexually dimorphic regulatory mechanisms of PRL secretion. Moreover, demonstration that hypothalamic and pituitary VIP levels vary in opposite directions suggests that VIP is differentially regulated at the two sites.

The effects of cholinergic and serotoninergic drugs on motility in vitro of Haplometra cylindracea (Trematoda: Digenea)

The spontaneous activity of the somatic muscle of the amphibian lung fluke, Haplometra cylindracea has been recorded in vitro, using an isometric force transducer system. Normal movement consisted of a continuous series of regular contractions which were maintained for over 4 h. Acetylcholine (ACh) inhibited motility at a concentration of 1 X 10(-3)M induced a flaccid paralysis. A similar response occurred with the cholinomimetric drugs, carbachol and nicotine, although in these instances the inhibition was less easily reversed by washing with frog Ringer. The inhibitory effect of ACh was blocked by d-tubocurarine but not by atropine. Serotonin (5-HT) caused an increase in the frequency and amplitude of contractions and the effect was blocked by methysergide. No uniform response was observed with 3-hydroxytryptamine (3-HT), but both reserpine and fluoxetine inhibited worm movement. Results suggest that the somatic musculature of the worm is controlled, at least in part, by an inhibitory cholinergic and an excitatory serotoninergic system.

Beta 2-adrenergic receptor regulation after transfection into a cell line deficient in the cAMP-dependent protein kinase

A mouse beta 2-adrenergic receptor (beta 2AR) DNA clone was transfected and expressed in a mouse adrenocortical tumor cell line (Kin8) that lacks both beta 2AR and cAMP-dependent protein kinase (PKA). The receptor displayed a characteristic beta 2AR agonist binding profile that was similar to that observed in beta 2AR-transfected PKA+ mouse adrenocortical tumor cells (Y1). Isoproterenol treatment of beta 2AR-transfected Kin8 and Y1 cells resulted in a rapid loss of surface beta 2AR, as determined by the binding of the hydrophilic beta 2AR radioligand [3H]CGP 12177 [( 3H]CGP), followed by a decrease in adenylate cyclase activity. Sequestration of beta 2AR in Kin8 cells was beta 2AR agonist specific, temperature dependent, and rapidly reversible. Repeated treatment and recovery from isoproterenol incubation resulted in a cycling of surface [3H]CGP binding. The reappearance of [3H]CGP binding following short isoproterenol treatment was not affected by cycloheximide treatment of the cells. Prolonged incubation of beta 2AR-transfected Kin8 cells with isoproterenol resulted in the down-regulation of beta 2AR protein without a change in beta 2AR mRNA levels. Polysome profiles of control and down-regulated cells revealed that translation of beta 2AR mRNA is inefficient and does not change upon prolonged agonist treatment. Protein synthesis was required to reverse the down-regulation of beta 2AR. These results indicate that neither sequestration nor down-regulation of beta 2AR depends on PKA.

Neuropeptide Y (NPY) and vasopressin (AVP) in the hypothalamo-neurohypophysial axis of salt-loaded or Brattleboro rats

A close anatomical relationship between nerve terminals containing neuropeptide Y (NPY) and vasopressin (AVP) has been demonstrated in the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON). Furthermore, injections of NPY into the SON increased plasma concentrations of AVP in the rat. These data suggest a potential involvement of hypothalamic NPY in fluid homeostasis in the rat. Therefore, we have studied the effect of elevated plasma osmolality on the concentration of NPY and AVP in the hypothalamus and neurointermediate lobe (NIL) of the pituitary gland. Furthermore, we measured the concentration of NPY in the AVP-deficient Brattleboro rat, which suffers from diabetes insipidus and hyperosmolality. Salt-loading increased plasma osmolality and the concentration of AVP from 2.0 +/- 0.5 to 4.1 +/- 0.6 pg/ml after 7 days. The concentration of NPY in the NIL doubled after 7 days of salt-loading, from 7.9 +/- 0.6 ng/mg protein to 15.2 +/- 1.4 ng/mg protein, whereas AVP concentrations fell from 2285.7 +/- 210.9 ng/mg protein to 187.5 +/- 2.5 ng/mg protein. AVP concentrations in the ME increased transiently after 2 days of salt-loading and returned to control levels after 7 days. In contrast, NPY concentrations in the ME were unchanged at 2 days and were increased 61% after 7 days. NPY concentrations also were significantly elevated after 7 days of salt-loading in the preoptic area (POA) and mediobasal hypothalamus (MBH). The concentration of NPY in the NIL of the homozygous Brattleboro rat was 2-fold greater than in the heterozygous Brattleboro rat and 4-fold greater than in Sprague-Dawley rats used as controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Substance P and gastrin releasing peptide in bovine mesenteric lymphatic vessels: chemical characterization and action

Alcoholic extracts of bovine mesenteric lymphatic vessels were assayed for the presence of SP, GRP, VIP, PHI, GIP and NT using specific radioimmunoassays. SP and GRP immunoreactivities were detected at concentrations of 190 +/- 20 and 1,000 +/- 130 pg.g-1, respectively. No significant levels of immunoreactivity were detected for any of the other peptides. SP and GRP immunoreactivities coeluted with their synthetic counterparts from both Sephadex G-50 and reversed phase HPLC columns. Synthetic SP (10(-9)-10(-7) M) and the naturally occurring analogue of GRP, bombesin (10(-9)-10(-7) M), increased spontaneous contraction rate in isolated vessel segments. This excitatory effect was not blocked by the alpha-adrenoceptor antagonist phentolamine (3 x 10(-6) M).