Coccidioidin and merthiolate in previously sensitized animals.

The effect of merthiolate, which is used as a preservative in skin test materials, on skin test reactions was determined in guinea pigs. In four groups of animals, merthiolate in basal medium produced skin tests at 24 and 48 h characterized by erythema and/or induration in an intermediate region, i.e., 5 plus or minus 2.2 mm. One of the four groups of animals was a nonsensitized control group. The other three groups were subcutaneously sensitized with (i) merthiolate and saline, (ii) killed Coccidioides immitis arthrospores, and (iii) merthiolate with killed C. immitis arthrospores. Coccidioidin only and merthiolate in coccidioidin produced positive delayed results in groups 3 and 4, which were sensitized with arthrospores. A synergistic effect of merthiolate and coccidioidin was observed in animals of group 4 sensitized by merthiolate with killed C. immitis arthrospores. This effect was observed at 24 h when positive reactions of coccidioidin with merthiolate were significantly greater than skin tests with plain coccidioidin.     

Correlation of proliferation of lung epithelium with intramuscular sensitization and complement-fixing antibody to respiratory syncytial virus in the golden hamster.

Intramuscular sensitization of hamsters with several forms of respiratory syncytial virus (RSv) caused proliferation of lung epithelium. In contrast, intranasal injection of live virus rarely resulted in this phenomenon. A correlation existed between proliferation of lung epithelium and presence of complement-fixing antibody, but not between lung disease and delayed skin reactions. Complement-fixing antibody to RSv was found to be independent of the influence of the thymus.     

Abnormalities of cholesterol metabolism in autism spectrum disorders.

Although Smith-Lemli-Opitz Syndrome (SLOS), a genetic condition of impaired cholesterol biosynthesis, is associated with autism [Tierney et al., 2001; Am J Med Genet 98:191-200.], the incidence of SLOS and other sterol disorders among individuals with autism spectrum disorders (ASD) is unknown. This study investigated (1) the incidence of biochemically diagnosed SLOS in blood samples from a cohort of subjects with ASD from families in which more than one individual had ASD and (2) the type and incidence of other sterol disorders in the same group. Using gas chromatography/mass spectrometry, cholesterol, and its precursor sterols were quantified in 100 samples from subjects with ASD obtained from the Autism Genetic Resource Exchange (AGRE) specimen repository. Although no sample had sterol levels consistent with SLOS, 19 samples had total cholesterol levels lower than 100 mg/dl, which is below the 5th centile for children over age 2 years. These findings suggest that, in addition to SLOS, there may be other disorders of sterol metabolism or homeostasis associated with ASD.     

4E-binding protein phosphorylation and eukaryotic initiation factor-4E release are required for airway smooth muscle hypertrophy

The molecular mechanisms of airway smooth muscle hypertrophy, a feature of severe asthma, are poorly understood. We previously established a conditionally immortalized human bronchial smooth muscle cell line with a temperature-sensitive SV40 large T antigen. Temperature shift and loss of large T cause G1-phase cell cycle arrest that is accompanied by increased airway smooth muscle cell size. In the present study, we hypothesized that phosphorylation of eukaryotic initiation factor-4E (eIF4E)-binding protein (4E-BP), which subsequently releases eIF4E and initiates cap-dependent mRNA translation, was required for airway smooth muscle hypertrophy. Treatment of cells with chemical inhibitors of PI 3-kinase and mammalian target of rapamycin blocked protein synthesis and cell growth while decreasing the phosphorylation of 4E-BP and increasing the binding of 4E-BP to eIF4E, consistent with the notion that 4E-BP1 phosphorylation and eIF4E function are required for hypertrophy. To test this directly, we infected cells with a retrovirus encoding a phosphorylation site mutant of 4E-BP1 (AA-4E-BP-1) that dominantly inhibits eIF4E. Upon temperature shift, cells infected with AA-4E-BP-1, but not empty vector, failed to undergo hypertrophic growth. We conclude that phosphorylation of 4E-BP, eIF4E release, and cap-dependent protein synthesis are required for hypertrophy of human airway smooth muscle cells.     

Effects of nitric oxide synthase inhibition by l-NAME on oxygen uptake kinetics in isolated canine muscle in situ

We hypothesized that an acute bout of strenuous, non-damaging exercise would increase rates of protein synthesis of collagen in tendon and skeletal muscle but these would be less than those of muscle myofibrillar and sarcoplasmic proteins. Two groups ( n = 8 and 6) of healthy young men were studied over 72 h after 1 h of one-legged kicking exercise at 67% of maximum workload ( W _max). To label tissue proteins in muscle and tendon primed, constant infusions of [1-¹³C]leucine or [1-¹³C]valine and flooding doses of [¹⁵N] or [¹³C]proline were given intravenously, with estimation of labelling in target proteins by gas chromatography–mass spectrometry. Patellar tendon and quadriceps biopsies were taken in exercised and rested legs at 6, 24, 42 or 48 and 72 h after exercise. The fractional synthetic rates of all proteins were elevated at 6 h and rose rapidly to peak at 24 h post exercise (tendon collagen (0.077% h⁻¹), muscle collagen (0.054% h⁻¹), myofibrillar protein (0.121% h⁻¹), and sarcoplasmic protein (0.134% h⁻¹)). The rates decreased toward basal values by 72 h although rates of tendon collagen and myofibrillar protein synthesis remained elevated. There was no tissue damage of muscle visible on histological evaluation. Neither tissue microdialysate nor serum concentrations of IGF-I and IGF binding proteins (IGFBP-3 and IGFBP-4) or procollagen type I N-terminal propeptide changed from resting values. Thus, there is a rapid increase in collagen synthesis after strenuous exercise in human tendon and muscle. The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation.     

Molecular Analysis of SV-40-CAL,a New Slow Growing SV-40 Strain from the Kidney of a Caged New World Monkey with Fatal Renal Disease

A decline of the Callimico goeldii population in American zoos is presently occurring due to glomerulonephritis of unknown etiology. We hypothesized that this emerging idiopathic fatal renal disease (IFRD) was caused by a virus. We therefore attempted to isolate virus from the kidneys three C. goeldi in Illinois that had IFRD. Along with other viruses, Simian virus 40 (SV-40) strain CAL was isolated. SV-40-CAL is currently the slowest-growing natural isolate of SV-40 in CV-1 cells. Inefficient SV-40-CAL growth in CV-1 cells stems from two features: a suboptimal protoarchetypal regulatory region, and a Large tumor antigen gene sequence like that of SV-40 strain T302, previously considered the slow-growing natural isolate of SV-40. To our knowledge, this is the first documented isolation of SV-40 from a New World monkey outside of a laboratory setting. Though SV-40 is renaltropic, the role of SV-40-CAL in IFRD is uncertain. Transmission of SV-40 to C. goeldii through anthropogenic activity is suspected.     

The distribution of the projection from the hippocampal formation to the nucleus accumbens in the rat: an anterograde- and retrograde-horseradish peroxidase study

We have investigated the distribution and organization of the projection from the hippocampal formation to the nucleus accumbens in the rat. In the first experiments, horseradish peroxidase was injected into the fimbria fornicis. This procedure resulted in massive anterograde labelling of fornix fibers, and enabled the hippocampo--accumbens projection to be charted in detail. Labelled fornix fibers are distributed to the entire length of the nucleus accumbens and do not spread lateral to the anterior limb of the anterior commissure, that is, the projection is limited to the medial nucleus accumbens. Terminal labelling is particularly dense in a caudal dorsomedial sector of accumbens immediately adjacent to the septum. In the second part of the study, horseradish peroxidase was microelectrophoretically injected into the nucleus accumbens, in order to confirm the findings from the anterograde experiments. When the deposit was localized within the fornix distribution field, as indicated by the first experiment, retrogradely-labelled cells were observed in the subiculum, prosubiculum, and to a lesser extent, in hippocampal field CAI. When the deposit was located outside of the fornix distribution field, no hippocampal labelling was noted. The topography of the projection, suggested by the retrograde labelling experiments, is discussed. The findings confirm earlier reports of such a projection from the hippocampal formation to the nucleus accumbens, and with the use of a relatively novel anterograde-horseradish peroxidase technique, provide a picture of fiber labelling representing the entire field of origin of the fornix system. The striatal projection field of this pathway is discussed in relation to other striatal afferents, with particular emphasis on limbic afferentation of the striatum. Finally, the so-called 'hippocampal district' of striatum is discussed with respect to its neurotransmitter composition, as well as its functional importance regarding limbic system influence on central motor mechanisms.     

The amygdalostriatal projection in the rat—an anatomical study by anterograde and retrograde tracing methods

Tritiated leucine and proline injected into the amygdaloid complex was found to label a voluminous amygdalostriatal fiber system which is distributed to all parts of the striatum except an antero-dorsolateral striatal sector. The connection is established by way of the longitudinal association bundle as well as the stria terminalis, and includes a modest (10–15%), symmetrically distributed contralateral component conveyed by the anterior commissure. Both autoradiographic findings and subsequent observations in retrograde cell-labelling (horseradish peroxidase) material indicate that the amygdalostriatal projection originates mainly from the nucleus basalis lateralis amygdalae, in much lesser volume from the nucleus basalis medialis, and minimally from the nucleus lateralis amygdalae; no other contributing amygdaloid cell group could be identified.A comparison of the present findings with earlier reports indicates that the amygdalostriatal projection widely overlaps the striatal projections from the ventral tegmental area, the mesencephalic raphe nuclei and the prefrontal cortex. Like the amygdalostriatal projection, these striatal afferents largely or entirely avoid the antero-dorsolateral striatal quadrant, which thus appears to be the striatal region most sparsely innervated by afferents originating from structures within the circuitry of the limbic system. Findings in additional autoradiographic material identify this relatively non-limbic striatal quadrant as the main region of distribution of the corticostriatal projection from the sensorimotor cortex.