Effect of low intensity laser (830 nm) irradiation on skin temperature and antidromic conduction latencies in the human median nerve: relevance of radiant exposure

The effects of low intensity near-infrared laser radiation (830 nm; 1.5-12 J/cm2; continuous wave) on peripheral neurophysiology and skin temperature were investigated using antidromic conduction studies in the human median nerve in vivo. Healthy human volunteers (n = 80) were recruited and randomly allocated to one of two control (n = 30) or five laser groups (1.5, 3.0, 6.0, 9.0, and 12 J/cm2; n = 10 per group). Analysis of variance (ANOVA) in negative peak latency difference scores (NPLDs) and skin temperature over a 20 min period post-irradiation demonstrated a significant decrease in skin temperature following irradiation at the lowest radiant exposure (1.5 J/cm2) coupled with a significant increase in NPLDs (P < 0.05). While no such (significant) changes were found in the other laser groups, it was found that observed changes (increases and decreases) in NPLDs were inversely related to changes in skin temperature. These findings demonstrate measurable peripheral neurophysiological effects of laser radiation concomitant with changes in skin temperature; however, further studies are indicated to establish the precise relationship between the observed effects on skin temperature and nerve conduction.

Low intensity laser irradiation inhibits tritiated thymidine incorporation in the hemopoietic cell lines HL-60 and U937

The purpose of this study was to determine the effect of low intensity laser irradiation (660 nm, 12 mW, 5 kHz) on tritiated thymidine incorporation in two hemopoietic cell lines, HL-60 and U937. Cells were suspended at a concentration of 1 x 10(6)/ml in their respective serum-free media and irradiated at energy densities from 1.0 to 11.5 J/cm2. Twenty-four hours after irradiation the cells were assayed for their ability to incorporate tritiated thymidine (3H-TdR) in comparison with nonirradiated cells. Analysis by two-way analysis of variance (ANOVA) for unrelated groups showed that laser irradiation at all energy densities > or = 5.8 J/cm2 produced a significant decrease in 3H-TdR incorporation (P < 0.05) into HL-60 cells. In U937 cells, irradiation at energy densities of 5.8, 7.2, and 11.5 J/cm2 caused a similar reduction in 3H-TdR incorporation (P < 0.01), although not at 8.6 and 9.6 J/cm2. The temperature of each cell suspension was recorded both during and immediately postirradiation, and no significant thermal changes were observed. These findings demonstrate a direct photobiological effect of laser irradiation on these two cell lines. The precise mechanism for this effect is unknown but may have significance in understanding the biological action of laser's known therapeutic effectiveness in promoting wound repair.

Incidence and simple management of priapism following dynamic infusion cavernosometry-cavernosography

Of 239 patients with erectile dysfunction (aged 36 to 70 years) who were evaluated with dynamic infusion cavernosometry-cavernosography, 32 (13.4%) developed priapism after the procedure and were successfully managed with immediate intracorporal injection of phenylephrine. No single risk factor for the development of priapism was identified in this group. Early pharmacologic intervention for priapism induced by dynamic infusion cavernosometry-cavernosography is a simple, safe, and time-saving measure to achieve detumescence and prevent potential sequelae such as corporal ischemia or fibrosis.

Neural modulation of bovine mesenteric lymph node contraction

Spontaneous isometric contractions and field-evoked responses were recorded in vitro from strips of bovine mesenteric lymph node capsule. Field stimulation (0.3 ms pulses, 60 V nominal, 2 min trains) at frequencies > or = 2 Hz evoked a frequency-dependent increase in baseline tension which was maximum at frequencies > or = 16 Hz. Evoked contractions were significantly reduced (P = 0.02) by the neurotoxin tetrodotoxin (10(-6) M) although they were unaffected by the alpha-adrenoceptor antagonists phentolamine, rauwolscine and prazosin (3 x 10(-6) M). Similarly, responses were unaffected by the beta-adrenoceptor antagonist propranolol (10(-6) M), the cholinergic antagonist atropine (10(-6) M) or the uptake blocker cocaine (10(-6) M). Field-evoked contraction was also unaffected by a 30 min exposure to alpha,beta-methylene ATP (10(-6) M). The results suggest that bovine lymph node capsular smooth muscle is innervated by excitatory nerves which are non-adrenergic, non-cholinergic and non-purinergic in nature.

A novel expression system for Gs-coupled receptors

Renal epithelial cells LLC-PK1 secrete high amounts of urokinase-type plasminogen activator (uPA) when stimulated through the cAMP-signaling pathway. Here we show that this characteristic can be used to identify rapidly LLC-PK1-derived cell lines expressing heterologous receptors that couple to Gs-proteins. A genomic clone encoding the mouse beta 2 adrenergic receptor (beta 2AR) was transfected stably into LLC-PK1 cells. Drug-resistant colonies were subsequently stimulated with isoproterenol and screened for the secretion uPA activity. Positive clones displayed dose-dependent uPA activity in response to isoproterenol, specifically bound the beta 2AR-agonist iodocyanopindolol and expressed beta 2AR-mRNA. The functional coupling of beta 2AR expression to the inducible uPA gene establishes that LLC-PK1 cells can be used to assay for beta 2AR (and beta 2AR-agonist) function. Our data suggest that this system can be used for functional expression of other heterologous receptors that couple to Gs-proteins.

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.