Actigraphy: A Means of Assessing Circadian Patterns in Human Activity

-Twenty-three diurnally active (0705-2333), healthy persons between 22 and 54 yrs of age and without history of sleep abnormality were monitored continuously for 120 consecutive hr (five days) by wrist actigraphy. Circadian rhythms of high amplitude were detected by cosinor analysis for each participant and for the groups of 10 males and 13 females with the average span of heightened activity timed between ∼1330 and 1605. The circadian peak-trough difference in wrist movement was marked, equalling aproximately 75% of the 24-hr mean level. In 19 of 23 participants, the 24-hr mean of wrist activity varied between 140-180 movements/min, with four persons exhibiting lesser means of 110-140 movements/min. With respect to the daytime span of activity, the mean wrist movement of individual participants ranged from 155-265 movements/min, with the majority (20/23) varying between 185-245 movements/min. During nocturnal sleep the mean wrist activity level was quite low, varying between individuals from 5 to 25 movements/min for 21 of 23 persons. Wrist actigraphy proved to be well-accepted and was a most reliable means of monitoring aspects of body movement during activity and sleep in ambulatory persons adhering to usual life habits and pursuits.     

Interactions of chiral molecules with an (r)-n-(3,5-dinitrobenzoyl) phenylglycine HPLC stationary phase

Forty different chiral molecules were studied by liquid chromatography with a Pirkle-type, (R)-N-(3,5-dinitrobenzoyl) phenylglycine (DNBPG), chiral stationary phase column. The dramatic effect of a small molecular change on chiral recognition was demonstrated using DL-amino acid derivatives. The inductive effect on chiral recognition was also studied using trifluoro-, trichloro-, dichloro-, monochloroacetyl, and acetyl derivatives of four different chiral amines. The study of the enantiomer separation of 11 different crown ethers of 2,2′-binaphthyldiyl showed that the rigidity of the chiral center can be an additional parameter in chiral recognition for the DNBPG phase but not for a β-cyclodextrin bonded chiral phase. It is apparent from this study that steric effects, inductive effects, and molecular rigidity play important roles in chiral recognition with DNBPG chiral stationary phases.     

Initial steps in the degradation of benzene sulfonic acid, 4-toluene sulfonic acids,and orthanilic acid in Alcaligenes sp. strain O-1

Alcaligenes sp. strain O-1 grew with benzene sulfonate (BS) as sole carbon source for growth with either NH₄ ⁺ or NH₄ ⁺ plus orthanilate (2-aminobenzene sulfonate, OS) as the source(s) of nitrogen. The intracellular desulfonative enzyme did not degrade 3- or 4-aminobenzene sulfonates in the medium, although the enzyme in cell extracts degraded these compounds. We deduce the presence of a selective permeability barrier to sulfonates and conclude that the first step in sulfonate metabolism is transport into the cell. Cell-free desulfonation of BS in standard reaction mixtures required 2 mol of O₂ per mol. One mol of O₂ was required for a catechol 2,3-dioxygenase. When meta ring cleavage was inhibited with 3-chlorocatechol in desalted extracts, about 1 mol each of O₂ and of NAD(P)H per mol of BS were required for the reaction, and SO₃ ^2- and catechol were recovered in high yield. Catechol was shown to be formed by dioxygenation in an experiment involving ¹⁸O₂. 4-Toluene sulfonate was subject to NAD(P)H-dependent dioxygenation to yield SO₃ ^2- and 4-methylcatechol, which was subject to meta cleavage. OS also required 2 mol of O₂ per mol and NAD(P)H for degradation, and SO₃ ^2- and NH₄ ⁺ were recovered quantitatively. Inhibition of ring cleavage with 3-chrorocatechol reduced the oxygen requirement to 1 mol per mol of OS SO₃ ^2- (1 mol) and an unidentified organic intermediate, but no NH₄ ⁺, were observed.     

Presence of serum albumin in normal human epidermis: Possible implications for the nutrition and physiology of stratified epithelia

In this paper, using both immunofluorescence and protein biochemistry techniques, we present definitive evidence that plasma proteins such as albumin are present within normal human epidermis. This result confirms several previous reports supporting the idea that relatively large molecules can diffuse through the epidermal basement membrane into epidermis. Our results bring new insights for discussing how hydrophobic ligands or drugs present in the bloodstream and bound to plasmatic carriers can reach epidermal cells of all layers.Abbreviations CHAPS 3-[3-cholamidopropyl dimethylammonio] propane sulfonate - kD kilodaltons - BSA bovine serum albumin - 2ME 2-mercaptoethanol - DTT dithiothreitol - SDS sodium dodecyl sulfate - pI isoelectric point - Mw molecular weight - Tris Tris-(hydroxymethyl) aminomethane - 1D one dimensional - 2D two dimensional - PAGE poly acrylamide gel electrophoresis - MEM Minimal Eagle's Medium     

Distribution of glutamate decarboxylase-like immunoreactivity in the sixth abdominal ganglion of the cockroach Periplaneta americana

Summary An antiserum against glutamate decarboxylase (GAD) of the rat brain was used to locate GAD activity in sections of the nervous system of the cockroach, Periplaneta americana. The sixth abdominal ganglion was chosen because electrophysiological evidence suggests the presence of GABAergic inhibitory synapses in the cereal-giant interneuron system. Groups of somata and numerous fibres and tracts were positively labelled by the GAD antiserum. A posterior group of labelled somata could be identified close to the entry of the cereal nerves. A line of somata clusters lay along a ventro-lateral furrow. Another discrete row of GAD-like cells was located dorso-laterally. Some small cells among the dorsal unpaired neurons were labelled. A small central group appeared under these cells. An abundance of GAD-like processes and transversal tracts were found within the neuropile. The different systems of GABAergic inhibitors in the ganglion are discussed; in particular we show that the fibres of cereal nerve X are not labelled. This demonstrates that the latter act on the giant fibres via interneurons. We suggest that the group that sends axons into the overlapping region between the cereal nerve and the giant fibre could be the inhibitory interneurons involved in this system.     

Structural studies on cyanobacterial photosystem I

The cyanobacterial photosystem, I complex from Synechococcus sp. PCC6301 contains polypeptides of apparent M_r of 70,000, 18,000, 17,700, 16,000 and 10,000. Procedures were developed for the purification of the M_r 17,700 and 10,000 polypeptides. Amino acid analyses showed the absence of cystine and cysteine from these polypeptides. Amino-terminal sequences of 98 residues for the M_r 17,700 polypeptide and of 42 residues for the M_r 10,000 polypeptide were determined. Studies of pigment distribution within the photosystem I complex indicated that the binding of chlorophyll a and -carotene is in part dependent on the presence of these polypeptides.Abbreviations PSI photosystem I - P700 reaction center of PSI - SDS sodium dodecylsulfate - TBS tris-buffered saline - TTBS TBS containing Tween-20     

Complications of Gastroesophageal Reflux

An edited summary of an Interdepartmental Conference arranged by the Department of Medicine of the UCLA School of Medicine, Los Angeles. The Director of Conferences is William M. Pardridge, MD, Professor of Medicine.Several specialists have recently recognized that gastrointestinal reflux causes complications resulting in significant disease. It causes discomfort, indigestion, esophagitis, Barrett''s esophagus, and carcinoma of the esophagus. Pediatricians attribute many early pulmonary problems, and even some sudden deaths in infants, to the reflux of gastric contents. Otolaryngologists now recognize that many cases of nonbacterial, nonspecific pharyngitis and laryngitis are due to the reflux of gastrc acid secretions. Contact granuloma and cancer of the larynx may, in some instances, be secondary to nocturnal reflux. Thoracic surgeons and pulmonologists believe chronic tracheobronchitis and some cases of pulmonary disease are attributable to recurrent bathing of the respiratory epithelium by aspirated gastric contents. An awareness of the many complications of gastrointestinal reflux should lead to a multidisciplined attack on the factors responsible for these diseases.     

The synthetic precursor specific region of pre-pro-parathyroid hormone forms ion channels in lipid bilayers

We have used the chemically synthesized sequence of pre-pro-parathyroid hormone and several of its analogues to test the notion that the capacity of amphipathic peptides to aggregate in membranes and form ion-permeable channels correlates with their ability to function as signal sequences for secreted proteins. We found that pre-pro-parathyroid hormone (the signal sequence and pro-region of parathyroid hormone (M)), as well as some of its analogues, forms aggregates of monomers which are ion-permeable. The ion-permeable aggregates (2–3 monomers) formed by (M) are voltage-dependent and are more permeable for cations than for anions. The compounds which formed ion channels in bilayers also acted as potential signal sequences. We conclude that the ability of peptides to form ion-permeable pathways in bilayers may be correlated to their ability to function as signal peptides.     

Antibodies to Cholinergic Neurons in Alzheimer''s Disease

Alzheimer's disease (AD) is associated with degenerative changes in nuclei of the basal forebrain which provide most of the cholinergic input to the cortex and hippocampus and with a reduction in presynaptic cholinergic parameters in these areas. Although the etiology and pathogenesis of AD are not known, several reports indicate the involvement of immunological mechanisms. In the present work we examined the existence of antibodies in sera of AD patients that bind specifically to cholinergic neurons. As antigens we employed the purely cholinergic electromotor neurons of the electric fish Torpedo which are chemically homogeneous and cross-react antigenically with human and other mammalian cholinergic neurons. Our findings show that immunoglobulins from sera of AD patients bind to a specific antigen (molecular mass 200 kilodaltons) in the cell bodies and axons of Torpedo electromotor neurons and that the levels of such antibodies are significantly higher in AD patients than in controls. The possible role of these antibodies in the cholinergic dysfunction in AD and their diagnostic potential are discussed.