Nerve growth factor (NGF) prevents degeneration of cholinergic neurons in the central nervous system (CNS), and has potential as a therapeutic treatment for Alzheimer's disease. The inability of NGF to cross the blood-brain barrier has prompted pharmacological approaches investigating peripherally administered compounds that stimulate release of endogenous NGF. This study describes the NGF-releasing properties of six human astrocytoma and glioblastoma cell lines (SW 1088, SW 1783 and CRL 1718 astrocytomas, and U-138, U-373, and T98G glioblastomas). Using a highly specific two-site ELISA for human NGF, basal NGF release could be detected in all cell lines, with the lowest level in the T98G line (approximately 80 pg NGF/ml). Cell lines tested with a variety of compounds for 24 h in serum-free media demonstrated stimulation of NGF release by distinct mechanisms. NGF levels were markedly elevated (up to 8-fold above vehicle-treated cells) when stimulated with the cytokine interleukin-1 beta (IL-1 beta). Phorbol ester stimulated NGF release 4-fold. Clenbuterol, 4-methyl catechol, and propentofylline had little activity, while 6-(4-hydroxybutyl)-2,3,5,-trimethyl-1,4,benzoquinone (TMQ), dexamethasone and 1,25-dihydroxyvitamin D3 elevated NGF levels 3-fold. These data indicate differences in the ability of human astrocytoma and glioblastoma cells to release NGF when stimulated with mechanistically distinct compounds.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Molecular cloning of cDNA for murine interleukin-3.

The cDNA sequence for murine interleukin-3, one of the colony stimulating factors that regulate haematopoiesis, codes for a polypeptide of 166 amino acids including a putative signal peptide. The predicted amino acid sequence indicates that formation of mature interleukin-3 involves proteolytic removal of not only the signal peptide but additional amino-terminal amino acids.

Animals↗

PubMedDate not supplied

A rapid method for the production of erythrocytes in the state "EC4" and "EC43".

The present report describes simple methods for preparing red blood cells coated with complement components. Erythrocytes coated strongly with C4 and C3 (EC43 cells) can be prepared using the standard sucrose hemolysis reaction system. Erythrocytes coated with C4 but not C3 (EC4 cells) can be prepared by a slight modification (addition of EDTA to sucrose prior to adding serum). Occasional sera (especially from black subjects) produced weak C3 coating of red blood cells in the modified sucrose hemolysis reaction. This C3 coating could be entirely abolished (without reducing C4 coating) by using Mg++ poor serum produced by dialyzing serum against Mg++ free barbital buffer. The EC43 and EC3 cells are extremely useful in analysis of anticomplement antiglobulin sera.

Binding Sites↗

PubMedDate not supplied

Radioactive antiglobulin testing with 125I anti-C4 and anti-C3.

The report describes methods for quantitating C4 and C3 coating of red blood cells using 125I anti-C4 and anti-C3. Two methods of preparing antisera were used; one involving absorption and elution from complement coated cells, and the other employing IgG fractions of antisera prepared on DEAE cellulose. White-cell-free red blood cells were used in the test procedure. Both the labeled antisera and the test cells were diluted in cold carrier proteins, initially bovine serum albumin, but more recently normal rabbit serum. We have found that normal rabbit serum is particularly effective in reducing the high uptake of nonspecific counts on normal cells, which had previously been a major technical problem for the radioactive antiglobulin technique. These methods are highly reproducible and relatively easy to perform once the labeled antisera are prepared. Furthermore, the use of labeled antisera permits analysis of specificity by the highly sensitive technique of radioimmunoelectrophoresis. One problem with the technique is that results indicate uptake of labeled antisera, rather than amounts of coating substances. Nonetheless, the ease of performance and the reproducibility of the method, make the procedure very useful in comparative studies of uptake of C4 and C3 by red blood cells.

Antibodies↗

PubMedDate not supplied

Evaluation of a tinnitus masking program: a follow-up study of 598 patients.

A follow-up study of two groups of tinnitus patients was conducted in an attempt to evaluate the tinnitus masking program. Results are discussed separately for a group of patients seen during the first three years of the program (1976 through 1978) and during the last year (1979). These results suggest an improvement in the management of the tinnitus patient and support this procedure as a viable technique in providing relief for selected tinnitus patients.

Audiology↗

PubMedDate not supplied

A comparison of reaction times to tinnitus and nontinnitus frequencies.

Reaction time (RT) to auditory stimuli has been suggested as a measure of loudness recruitment in humans and in subhuman primates. In this investigation, RT's were obtained for hearing-impaired subjects with tinnitus (the experimental group) and normal-hearing subjects without tinnitus (the control group) to three sets of frequencies. For the experimental group, these were the tinnitus frequencies (associated with abnormal thresholds), nontinnitus frequencies with thresholds similar to the thresholds of the tinnitus frequencies, and nontinnitus frequencies with thresholds within normal limits. For the control group, these frequencies were all associated with thresholds within normal limits. The only significant difference for RT's for the experimental group versus the control group was to the tinnitus frequencies. There were no significant differences for RT's for the control group among the three sets of frequencies. However, for the experimental group, RT's to each of the three sets of frequencies differed significantly from each other. This study suggests that the measurement of RT's to auditory stimuli provides an objective measure of tinnitus, a means for comparing human and subhuman data on tinnitus, a method for determining recruitment, and a possible technique for mapping areas of tinnitus.

Acoustic Stimulation↗

PubMedDate not supplied

Full-thickness burn to the hand from an automobile airbag.

An 18-year-old male was involved in a single car motor vehicle accident in which the driver's side airbag was deployed. He presented to the trauma center with complex injuries to the left hand, lacerations to the scalp, and a full-thickness burn to the ulnar aspect of the right hand that included the hypothenar area and the fifth digit. The patient was admitted to the trauma center and received immediate consultation from the burn service. He underwent debridement and split-thickness skin grafting of 50 cm2 of the right hand on postburn day 3. The graft became necrotic and the patient underwent debridement of the skin and the abductor minimi muscle of the right hand on postburn day 32. Split-thickness skin grafting and release of flexion contracture were successfully completed 18 days later. The police and fire departments reported that the airbag showed signs of thermal destruction. Upon request, Honda motors submitted information from the TRW safety systems and material safety data sheet (Mesa, Ariz, issued 1989) that showed that airbag canisters contain the chemicals sodium azide and cupric oxide. Water may react with sodium azide to form highly toxic and explosive hyfrazoic acid. These chemicals are converted to sodium hydroxide, which can cause significant chemical burns. In addition, these chemicals may ignite when exposed to live electrical wires or temperatures greater than 300 degrees F. We conclude that burns associated with damaged deployed airbags in motor vehicle accidents may be the results of both chemical and thermal injury. The extent of the burn wound may be underestimated, as our case illustrates. Full-thickness burns resulting from airbag deployment may require more aggressive initial debridement and treatment.

Accidents, Traffic↗