Body composition in the elderly: Total body water and anthropometry

Body composition measured with isotopic dilution was compared with anthropometric measurements. The study was carried out in 47 subjects from both sexes, 65 to 92 years old. Total body water (TBW), anthropometric measurements, and dynamometry were assessed. TBW was significatively higher in men than women and decreased with age. Dynamometry and fatfree mass were well correlated (r=0.73 in males and r=0.58 in females) and significantly different between sexes. A negative correlation was found for dynamometry with age, being significant for women. Linear regression equations to predict TBW from anthropometric measurements in males and females were obtained: Males: TBW(I)=19.349+0.617 weight(kg) — 0.931 mid-arm circumference(cm)+0.122 dynamometry (kg) Females: TBW(l)=−5.531+0.343 weight(kg)-0.213 triceps skinfold (mm)+ 0.148 dynamometry(kg) + 3.424 wrist diameter (cm). This simple model is proposed for use in epidemiological and field studies where other more sophisticated methods can not be applied.     

Potent gp120-like neurotoxic activity in the cerebrospinal fluid of HIV-infected individuals is blocked by peptide T.

The envelope protein of the human immunodeficiency virus (gp120) causes neuronal death in developing murine hippocampal cultures or rat retinal ganglion cells. In HIV-infected individuals, gp120 released from HIV-infected macrophages or other cells in the brain has been proposed as the etiology for the pathophysiology of AIDS central nervous system (CNS) disease by diffusing to act at a distance to cause damage and/or death to neighboring neurons. In this study, 28 cerebrospinal fluid (CSF) samples from HIV-infected individuals (79% were WR stage 1 and 2) and neurological disease controls were tested, blind to the investigator, for the presence of in vitro neuronal killing activity. Neurotoxic activity was detected with peak effects at a 1:10(5) dilution in CSF from 9/18 HIV-infected individuals and 1/10 neurological disease controls. Thus half of CSF from early stages of HIV disease are characterized by the presence of neurotoxic activity which is not present in control CSF (Fischers exact test, P < 0.05). The neuronal toxicity by patient CSF could be prevented by peptide T (1 nM). A monoclonal antibody to mouse CD4, RL.172, also attenuated or prevented CSF-induced neuronal killing in all four CSF samples tested. In addition, an antiserum to peptide T previously shown to bind gp120 and neutralize both infectively and direct gp120 neurotoxicity, neutralized the CSF factor. gp120, or a modified small fragment, is suggested to be the responsible toxic molecular entity. These results may be relevant to the pathophysiology of HIV-related CNS disease and the mechanism by which peptide T causes improvements.     

Degradation of extracellular matrix proteins (fibronectin, vitronectin and laminin) by serine-proteinases isolated from Lonomia achelous caterpillar hemolymph.

Lonomia achelous is a caterpillar distributed in southern Venezuela and in northern Brazil that causes an acute hemorrhagic syndrome in people who have contact with its bristles. The effect of the crude hemolymph and its chromatographic fractions (FDII, Lonomin V and Lonomin V-2) on extracellular matrix proteins was studied. The chromatographic fractions show activities similar to plasmin and urokinase. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both lonomins appear as a protein band of 25 kDa under reduced conditions. By exclusion chromatography, the molecular weights of Lonomin V and Lonomin V-2 were 26.5 and 24.5 kDa, respectively. Fibronectin, laminin and vitronectin were degraded by all venom components. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reduced conditions, shows that lonomins degrade fibronectin in four main fragments of 116, 60, 50 and 30 kDa. Molecular exclusion chromatography in native conditions shows that the molecular masses of these fragments are > or = 300, 62 and 27 kDa. The proteolytic effect of lonomins was abolished by benzamidine/HCl, iodoacetic acid and aprotinin. The extracellular matrix protein degradation together with the fibrino(geno)lytic activity of hemolymph and its fractions could explain, in part, the hemorrhagic syndrome, and the wound dehiscence in persons who have had contact with the L. achelous caterpillar.     

Characterization of digital dermatoglyphic features in Salazar Valley: comparison with other Basque valleys

Digital dermatoglyphics of a sample from the Basque Valley of Salazar, situated in the West of the Pyrenees, were analysed. The results showed bimanual differences in both sexes, and also sexual differences for both hands. The comparative study with other Basque valleys showed that, in spite of their supposed common origin, the geographic barriers and the isolation have generated a genetic/dermatoglyphic and linguistic differentiation.     

Detecting danger--or just another odorant? Olfactory sensitivity for the fox odor component 2,4,5-trimethylthiazoline in four species of mammals

2,4,5-trimethylthiazoline (TMT) is a volatile component of the anal gland secretion of the red fox and elicits behavioral and physiological fear responses in the rat. Using instrumental conditioning paradigms, we determined olfactory detection thresholds for TMT in three rats, a natural prey species of the red fox, and compared their performance to that of three squirrel monkeys, three spider monkeys and four pigtail macaques, all non-prey species of the red fox. We found that the rats were able to discriminate concentrations between 0.04 and 0.10 ppt (parts per trillion) of TMT from the odorless solvent which is by far the lowest olfactory detection threshold for an odorant reported in rats so far. In contrast, the spider monkeys needed 0.14-1.38 ppb (parts per billion), the pigtail macaques 0.41-4.07 ppb, and the squirrel monkeys 4.07-13.80 ppb to detect TMT which does not rank among the lowest olfactory thresholds reported for these three primate species. Thus, these results support the assumption that the behavioral relevance of an odorant may be an important determinant of a species' olfactory sensitivity.     

Responses to natural scenes in cat V1

Studies on processing in primary visual areas often use artificial stimuli such as bars or gratings. As a result, little is known about the properties of activity patterns for the natural stimuli processed by the visual system on a daily basis. Furthermore, in the cat, a well-studied model system for visual processing, most results are obtained from anesthetized subjects and little is known about neuronal activations in the alert animal. Addressing these issues, we measure local field potentials (lfp) and multiunit spikes in the primary visual cortex of awake cats. We compare changes in the lfp power spectra and multiunit firing rates for natural movies, movies with modified spatio-temporal correlations as well as gratings. The activity patterns elicited by drifting gratings are qualitatively and quantitatively different from those elicited by natural stimuli and this difference arises from both spatial as well as temporal properties of the stimuli. Furthermore, both local field potentials and multiunit firing rates are most sensitive to the second-order statistics of the stimuli and not to their higher-order properties. Finally, responses to natural movies show a large variability over time because of activity fluctuations induced by rapid stimulus motion. We show that these fluctuations are not dependent on the detailed spatial properties of the stimuli but depend on their temporal jitter. These fluctuations are important characteristics of visual activity under natural conditions and impose limitations on the readout of possible differences in mean activity levels.     

Alpha lipoic acid: a novel treatment for depression

Insulin resistance has been associated with people diagnosed with depression. Conversely, it has also been documented that diabetics have an increased risk of depression. Evidence suggests that insulin activity plays a role in serotonergic activity by increasing the influx of tryptophan into the brain. This increased influx of tryptophan has been shown to result in an increase in serotonin synthesis. In accordance with the serotonin theory of depression, it may be possible to treat depression by increasing insulin activity. The antioxidant alpha lipoic acid has been shown to increase insulin sensitivity and is used to treat people with diabetes. Therefore, the nutrient alpha lipoic acid should be clinically tested as an adjunct treatment for depression.     

Human Lyme arthritis and the immunoglobulin G antibody response to the 37-kilodalton arthritis-related protein of Borrelia burgdorferi

In Borrelia burgdorferi-infected C3H-scid mice, antiserum to a differentially expressed, 37-kDa spirochetal outer-surface protein, termed arthritis-related protein (Arp), has been shown to prevent or reduce the severity of arthritis. In this study, we determined the immunoglobulin G (IgG) antibody responses to this spirochetal protein in single serum samples from 124 antibiotic-treated human patients with early or late manifestations of Lyme disease and in serial serum samples from 20 historic, untreated patients who were followed longitudinally from early infection through the period of arthritis. These 20 patients were representative of the spectrum of the severity and duration of Lyme arthritis. Among the 124 antibiotic-treated patients, 53% with culture-proven erythema migrans (EM) had IgG responses to recombinant glutathione S-transferase (GST)-Arp, as did 59% of the patients with facial palsy and 68% of those with Lyme arthritis. In addition, 75 to 80% of the 20 past, untreated patients had reactivity with this protein when EM was present, during initial episodes of joint pain, or during the maximal period of arthritis. There was no association at any of these three time points between GST-Arp antibody levels and the severity of the maximal attack of arthritis or the total duration of arthritis. Thus, after the first several weeks of infection, 60 to 80% of patients had IgG antibody responses to GST-Arp, but this response did not correlate with the severity or duration of Lyme arthritis.     

An eighth complementation group of rodent cells hypersensitive to ultraviolet radiation

Two mutant lines (US31, US46) of mouse lymphoma cells that are hypersensitive to ultraviolet (UV) radiation were previously found to belong to different complementation groups. The mutants were tested for their ability to complement the six known complementation groups of UV-sensitive Chinese hamster ovary (CHO) cells, which are defective in nucleotide excision repair, as well as a seventh group represented by a V79 mutant. Hybrid cells were produced by fusion with polyethylene glycol and tested in situfor UV resistance. The mouse mutant US46 complemented all CHO mutants except UV61. Therefore, US46 is assigned to the same complementation group as UV61, and it is probably defective in the same locus. The mouse mutant US31 produced UV-resistant hybrid cells in each of the seven crosses, indicating that it forms an eighth complementation group among the rodent mutants. Thus, at least eight genes are likely required to repair UV damage in rodent cells.