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Biomedical subjects

L Aloe

Publications and source records attributed to L Aloe.

At least 163 records · Page 9Linked to original sources
PubMed1993

The effect of chronic ethanol intake on brain NGF level and on NGF-target tissues of adult mice.

The effect of ethanol consumption on the forebrain and hypothalamus of adult mice was investigated. A consistent decrease of biological activity and of nerve growth factor (NGF) immunoreactivity was observed in the hippocampus and hypothalamus of alcohol-treated mice. Biochemical studies also indicate that chronic ethanol intake causes a reduction in the level of choline-acetyltransferase in the septum, hippocampus and striatum, but not in the cortex and other brain regions. This study provides evidence that long-term ethanol intake causes impairment of brain NGF level and of the cholinergic enzyme, regulated by NGF, suggesting that NGF synthesis and/or biological activity is affected in alcohol-related brain neuropathology.

Alcoholism↗
PubMed1993

Neonatal capsaicin exposure affects isolation-induced aggressive behavior and hypothalamic substance P levels of adult male mice (Mus musculus).

Subcutaneous administration of capsaicin (50 mg/kg) at Postnatal Days 2 and 5 exerted long-term effects on isolation-induced aggressive behavior of adult mice (Mus musculus) of the CD-1 strain. Isolated capsaicin-treated mice (scored during a 10-min session) showed the highest frequency and the longest duration of total attacks, attacks, rattling, and offensive upright posture when compared with nonisolated capsaicin-treated subjects and both isolated and nonisolated vehicle control animals. Hypothalamic Substance P (SP) was assessed by radioimmunoassay. Capsaicin treatment significantly lowered hypothalamic SP content in both isolated and nonisolated mice. Moreover, individual scores of isolated capsaicin-treated subjects showed a significant correlation between SP depletion and expression of offensive upright posture. Isolation per se was revealed to play an important role in depleting SP from the hypothalamus.

Aggression↗
PubMed1993

Increased levels of NGF in sera of systemic lupus erythematosus patients.

Using a specific enzyme-linked immunosorbent assay (ELISA) for human nerve growth factor (NGF), serum levels in patients with systemic lupus erythematosus (SLE) were measured. We found a consistent increase in NGF levels in SLE patients compared with controls. A good correlation exists between serum NGF level and severity of clinical manifestation. We hypothesize that NGF might play a role in the pathogenesis of autoimmune disorders such as SLE.

Adolescent↗
PubMed1993

NGF is released into plasma during human pregnancy: an oxytocin-mediated response?

The presence of biologically active nerve growth factor (NGF) in the peripheral circulation of women during pregnancy, labour and lactation was investigated. Using a sensitive immunoenzymatic assay (ELISA), we found an approximately five-fold increase in plasma NGF levels during labour and lactation compared with the concentrations found at the term of gestation or in control healthy women. Since labour and lactation are characterized by activation of the hypothalamo-pituitary-adrenal axis and by high plasma levels of the neurohypophyseal hormone oxytocin, and since the intravenous injection of oxytocin in female rats causes a 176% increase in the hypothalamic levels of NGF, it is possible that the increased amount of circulating NGF is correlated with one or both of these events.

Adolescent↗
PubMed1993

NGF retards apoptosis in chick embryo bursal cell in vitro.

Recent studies have demonstrated that the action of nerve growth factor (NGF) is not restricted to neuronal cells but also affects cells of the immune system. In a previous work on the effect of NGF on the chick embryo bursa of Fabricius both in vivo and in vitro, we observed that NGF prolongs bursal cell survival in vitro. In the present study we report that the increase of viable cells in NGF-treated cultures is not due to a proliferative effect of NGF on bursal cells but to a reduction of cell mortality. The morphological analysis revealed that bursal cells in cultures die by apoptosis, which was also shown by the typical pattern of DNA fragmentation, a hallmark of this cell death process. It is concluded that NGF, with an action similar to that described in sympathetic neurons and PC12, could retard bursal cell death by influencing apoptosis.

Animals↗
PubMed1993

Laryngeal brain stem evoked response in the porcine model.

Exaggeration of normally protective laryngeal reflexes is thought to play a role in several disorders, including the sudden infant death syndrome. An analysis of brain stem neural activity following laryngeal stimulation may provide insight into the pathophysiology of pathologic laryngeal reflexes and help to identify individuals at risk for these disorders. The purpose of this study was to define the far-field brain stem activity following laryngeal stimulation in the porcine model. This activity has been termed the laryngeal brain stem evoked response and may represent a potentially useful and objective measure of the neuronal activity in the laryngeal reflex pathway. Electrical stimulation of the superior laryngeal nerve was performed in 14 mixed-breed piglets under a variety of physiologic conditions. A total of six positive and six negative discrete waves were detected, with mean latencies ranging from 1.24 to 7.16 milliseconds. Stimulations performed during hypoxic, hypercapneic, or hypocapneic conditions resulted in no significant differences in waveform latencies. There appears to be a reproducible, but somewhat variable, brain stem response elicited by superior laryngeal nerve stimulation that can be recorded via a far-field technique in the porcine model.

Animals↗
PubMed1993

The synovium of transgenic arthritic mice expressing human tumor necrosis factor contains a high level of nerve growth factor.

We have recently reported that nerve growth factor (NGF) increases in the synovium of patients affected by rheumatoid arthritis and in the synovium of pharmacologically-induced arthritis in animal models. In the present study, we demonstrate that arthritic transgenic mice which carry and express the human TNF gene (Tg197) also express elevated levels of NGF, and that subcutaneous injection of NGF-antibodies attenuates the loss of body weight caused by the development of disease in these mice. Along with our previous findings, which show an increase in the level of NGF during the acute phase of other autoimmune diseases, these results suggest a role of NGF in these pathologies. The functional significance of NGF in rheumatoid arthritis (RA) is currently under study.

Animals↗
PubMed1993

Influence of ethanol consumption on brain nerve growth factor and its target cells in developing and adult rodents.

In the present study the effect of alcohol consumption on brain nerve growth factor (NGF) and the NGF-target cells of adult male rats and pups exposed prenatally to ethanol is evaluated. It is hypothesized that NGF, a trophic agent for the survival and maintenance of basal forebrain cholinergic neurons, might be affected by the neurodegenerative events which occur during ethanol consumption. To test this hypothesis, we used adult rats exposed to ethanol for 16 weeks and pregnant rats exposed to ethanol for six days. Our experiments show that ethanol ingestion causes a reduction of NGF in the hippocampus, of choline acetyltransferase activity in both the septum and hippocampus, and in the distribution of NGF receptor in the basal forebrain cholinergic neurons. The results indicate that the damaging effect of alcohol on forebrain cholinergic neurons is also associated with impairment of central NGF-target structures.

Age Factors↗
PubMed1993

Level of nerve growth factor and distribution of mast cells in the synovium of tumour necrosis factor transgenic arthritic mice.

We have recently reported that nerve growth factor (NGF) increases in the synovium of patients affected by arthritis, as well as in animal models. We report here that the synovium of transgenic arthritic mice expressing human tumour necrosis factor (TNF) contains numerous mast cells (MC) and that their appearance is a phenomenon which was correlated to the local increase in NGF level. These findings provide further evidence that NGF plays a role in inflammation and suggest a functional link between NGF and MC.

Animals↗
PubMed1993

Immunohistochemical localization of nerve growth factor (NGF) and NGF-receptor in the hypothalamus of adult rats.

In the adult mammalian central nervous system (CNS) the nerve growth factor (NGF) has thus far been associated mainly with the metabolic support and pathophysiology of cholinergic basal forebrain (CBF) neurons. Recently, however, the presence of NGF and NGF mRNA has been demonstrated in the hypothalamus of adult mice. In addition there have been reports on the stimulation of the pituitary-adrenocortical axis by NGF. These and other findings suggest the involvement of NGF in hypothalamic functioning. The aim of the present study was to improve immunohistochemical methodologies for the investigation of NGF and NGF-receptor (NGF-r) in the hypothalamus of adult rats. Our results show NGF and NGF-r expression in various regions of the hypothalamus. Moreover, in some areas, distribution and morphology of immunoreactive neurons suggest neuronal colocalization of the two markers. To study the function of NGF in the hypothalamus, anti-NGF antibody was injected in the area of the paraventricular nucleus. We did not, however, find an effect of treatment on NGF-r immunoreactive neurons in this area.

Animals↗
PubMed1992

Multiple sclerosis patients express increased levels of beta-nerve growth factor in cerebrospinal fluid.

We describe the measurement of beta-nerve growth factor (NGF) content in cerebrospinal fluid (CSF) from multiple sclerosis (MS) patients compared with CSF from age-matched normal subjects using a specific sandwich immunoassay (ELISA). During acute attacks patients exhibit a significant increase of NGF content compared to controls. In contrast during remission the mean NGF levels in CSF markedly decrease. These results strongly indicate that increased NGF production in CSF is a characteristic feature of the MS inflammatory response.

Adolescent↗
PubMed1992

Nerve growth factor in the synovial fluid of patients with chronic arthritis.

Cytokines regulate nerve growth factor (NGF) synthesis during inflammatory processes. Since cytokines are also involved in the inflammatory processes of autoimmune rheumatic diseases, we examined levels of NGF in patients with rheumatoid or other types of chronic arthritis. NGF was present in the synovial fluid and synovium of patients with chronic arthritis, but was undetectable in control fluids. We conclude that NGF might be involved in the pathogenesis of arthritis.

Aged↗
PubMed1992

Studies on carrageenan-induced arthritis in adult rats: presence of nerve growth factor and role of sympathetic innervation.

Recent studies effected by our Institute indicate that various forms of human arthritis express both immunohistochemically and biologically active nerve growth factor (NGF) in the synovium. In the present study, we used a model of carrageenan-induced arthritis to further evaluate the effects of joint inflammation on NGF level. These studies showed that experimentally-induced arthritis in rats caused a significant increase in NGF in the perivascular area of the synovium. We also showed that injection into the synovium of purified NGF did not cause inflammation per se and that the destruction of peripheral sympathetic innervation significantly reduced both the inflammation and the level of NGF following carrageenan injection.

Animals↗
PubMed1992

NGF decreases isolation-induced aggressive behavior, while increasing adrenal volume, in adult male mice.

Intravenous administration of highly purified murine nerve growth factor (NGF, either 15 or 30 micrograms/subject/day) for six consecutive days to adult male mice of the CD-1 strain markedly influenced a number of items of aggressive behavior induced by 5 weeks of individual housing. Control mice received the same doses of cytochrome c. During a 20-min fighting session on day 7, both NGF-treated groups showed longer Latency to the first Attack, while Total Attacking Time and Aggressive grooming were significantly lower when compared to control animals. Twenty-four h later, adrenals from the NGF- and cytochrome c-treated groups were dissected and analyzed by means of a Vidas Image-Analyzer. NGF administration produced a remarkable dose-dependent increase in both adrenal weight and volume (particularly in the medullary zone), supporting the hypothesis that adrenals represent a possible target for the NGF release from submaxillary salivary glands occurring upon intraspecific fighting.

Adrenal Glands↗
PubMed1992

In vivo activated brain astrocytes may produce and secrete nerve growth factor-like molecules.

The cellular localization of the nerve growth factor-like immunoreactivity (NGF-LIR) has been studied in the septum and hippocampus of the rat brain 7 days following partial electrolytic lesion (2 mA, 30 s) of the septohippocampal pathways or after single intraventricular administration of 15 U of interleukin-1 beta (IL-1 beta). A double immunostaining technique which allowed a simultaneous localization of NGF-LIR and that of astroglia marker glial fibrillary acidic protein was used. Our data show that after both treatments, apart from neuronal localization of NGF-LIR typical for normal brain, many astrocytes both in the septum and hippocampus became NGF-like immunoreactive. Besides, NGF-LIR often formed a "halo" reaction around astrocytes. These results support the notion that activated in vivo brain astrocytes may, just as astrocytes growing in vitro, synthesize and secrete NGF-like molecules. Our findings may be of importance in considerations concerning trophic support to the cholinergic neurons of the basal forebrain nuclei whose impaired function is essentially responsible for some cognitive deficits in neurodegenerative diseases such as Alzheimer disease.

Animals↗
PubMed1992

In vivo and in vitro NGF studies on developing cerebellar cells.

The biological effect of nerve growth factor (NGF) in the early prenatal cerebellar cell was studied in vivo and in vitro with autoradiographic, tissue culture and immunohistochemical techniques. Iodinated NGF (125I-NGF) injected into the cerebella of 16-day-old rat embryos showed accumulation of this ligand in the Purkinje cell layers. The ability of these cells to accumulate NGF lasted to the 19th day of embryonic life. Cerebellar cells isolated from embryos of the same age, but not older embryos, cultured in vitro for two weeks in the presence of NGF, showed morphological characteristics similar to Purkinje-like cells. These findings suggest that NGF exerts a time-limited trophic effect on immature Purkinje cell precursors.

Animals↗
PubMed1992

Levocarnitine acetyl treatment promotes iris reinnervation following 6-hydroxydopamine-induced noradrenergic denervation in rats.

The effect of levocarnitine acetyl on neurite regeneration was evaluated following administration of 6-hydroxydopamine which caused a selective degeneration of peripheral catecholaminergic neurites in the irides of newborn and young rats. Levocarnitine acetyl 20 mg/kg body weight was administered either subcutaneously to newborn rats for 20 days or dissolved in drinking water to young rats for 90 days. Treatment with levocarnitine acetyl promoted neurite outgrowth following axotomy in both groups, thus demonstrating a stimulatory role of the substance in nerve regeneration of the peripheral nervous system. The results further confirm that levocarnitine acetyl is endowed with therapeutical efficacy in peripheral neuropathies.

Acetylcarnitine↗