Safety, pharmacokinetics, and pharmacodynamics of RSLV-132, an RNase-Fc fusion protein in systemic lupus erythematosus: a randomized, double-blind, placebo-controlled study.

Blood-borne RNA circulating in association with autoantibodies is a potent stimulator of interferon production and immune system activation. RSLV-132 is a novel fully human biologic Fc fusion protein that is comprised of human RNase fused to the Fc domain of human IgG1. The drug is designed to remain in circulation and digest extracellular RNA with the aim of preventing activation of the immune system via Toll-like receptors and the interferon pathway. The present study describes the first clinical study of nuclease therapy in 32 subjects with systemic lupus erythematosus. The drug was well tolerated with a very favorable safety profile. The approximately 19-day serum half-life potentially supports once monthly dosing. There were no subjects in the study that developed anti-RSLV-132 antibodies. Decreases in B-cell activating factor correlated with decreases in disease activity in a subset of patients.

The effect of recombinant mast cell growth factor on purified murine hematopoietic stem cells.

Pluripotent hematopoietic stem cells (PHSC) are very rare cells whose functional capabilities can only be analyzed indirectly. For a better understanding and possible manipulation of mechanisms that regulate self-renewal and commitment to differentiation of PHSC, it is necessary to purify these cells and to develop assays for their growth in vitro. In the present study, a rapid and simple, widely applicable procedure to highly purify day 14 spleen colony-forming cells (day 14 CFU-S) is described. Low density bone marrow cells (rho less than or equal to 1.078 g/cm3) were enriched by two successive light-activated cell sorting procedures. In the first sort, cells within a predetermined light scatter (blast cell) window that are wheat germ agglutinin/Texas Red (WGA/TxR) positive and mAb 15-1.4.1/fluorescein isothiocyanate negative (granulocyte-monocyte marker) were selected. In the second sort, cells were selected on the basis of retention of the supravital dye rhodamine 123 (Rh123). Cells that take up little Rh123 (Rh123 dull cells) and those that take up more Rh123 (Rh123 bright cells) were 237-fold and 132-fold enriched, respectively, for day 14 CFU-S. Both Rh123 fractions were cultured for various time periods in vitro in the presence of mast cell growth factor (MGF), with or without interleukin 3 (IL-3) or IL-1 alpha. Both Rh123 fractions proliferated in response to MGF alone as determined by a [3H]TdR assay or by counting nucleated cells present in the cultures over time. MGF also acted synergistically with both IL-3 and IL-1 alpha to promote stem cell proliferation. Stimulation of both Rh123 fractions with MGF alone did not result in a net increase of day 14 CFU-S. Stimulation with MGF + IL-3 or MGF + IL-alpha resulted in a 4.4- or 2.6-fold increase of day 14 CFU-S in the Rh123 dull fraction, and an 11.6-fold or 2.6-fold increase of day 14 CFU-S in the Rh123 bright fraction, respectively. The data presented in this paper indicate that in vitro MGF acts on primitive hematopoietic stem cells by itself and also is a potent synergistic factor in combination with IL-3 or IL-1 alpha.

Purification to homogeneity of B cell stimulating factor. A molecule that stimulates proliferation of multiple lymphokine-dependent cell lines.

Murine B cell stimulating factor 1 (BSF-1) was purified to homogeneity from supernatants of a stimulated thymoma cell line. A protein of 18.4 kD with a unique N-terminal amino acid sequence was identified. BSF-1 had a sp act of at least 3.28 X 10(8) U/mg. In addition to its B cell-stimulatory activity, BSF-1 also stimulated the proliferation of several IL-2- and IL-3-dependent cell lines. We conclude that BSF-1 is both a growth factor and a differentiation factor. Finally, these results also suggest additional biologic properties of BSF-1 on lineages besides B lymphocytes.

Microelectrophoresis of biogenic amines on hypothalamic thermosensitive cells.

The rat hypothalamus contains thermally insensitive, normally sensisitive, and highly thermosensitive cells. The responses of thermosensitive neurons to microelectrophoretically applied acetylcholine, norepinephrine, and 5-hydroxy-tryptamine were the same in both rats and cats. The firing rate of warm-sensitive interneurons was accelerated by acetylcholine and inhibited by norepinephrine. The firing rate of cool-sensitive interneurons was accelerated by norepinephrine and, in one case, was inhibited by 5-hydroxytryptamine. Thermodetector cells were relatively insensitive to these amines, but were sensitive to current flow. These results from the rat, but not from the cat, agree with the data for thermoregulatory responses following microinjection of these amines into the hypothalamus.

Cloning of a T cell growth factor that interacts with the beta chain of the interleukin-2 receptor.

A cytokine was identified that stimulated the proliferation of T lymphocytes, and a complementary DNA clone encoding this new T cell growth factor was isolated. The cytokine, designated interleukin-15 (IL-15), is produced by a wide variety of cells and tissues and shares many biological properties with IL-2. Monoclonal antibodies to the beta chain of the IL-2 receptor inhibited the biological activity of IL-15, and IL-15 competed for binding with IL-2, indicating that IL-15 uses components of the IL-2 receptor.

An immunocytochemical study of the serotonergic innervation of the thalamus of the rat.

The serotonergic innervation of the rat thalamus was studied with an indirect immunocytochemical technique using an antiserum raised against a serotonin-hemocyanin conjugate in animals pretreated with L-tryptophan and a monoamine oxidase (MAO) inhibitor. When pretreatment was not used there was a decrease in the number of immunoreactive fibers observed in the thalamic region. Innervation was greatest in nucleus ventralis corporis geniculati lateralis, and in the following midline nuclei: nucleus periventricularis, nucleus rhomboideus, and nucleus reuniens. Also well labeled were nucleus anterior ventralis, the intralaminar nuclei, and nucleus lateralis dorsalis. Moderate innervation was found in nucleus reticularis, nucleus anterior dorsalis, nucleus ventralis medialis, nucleus lateralis pars posterior, the posterior complex, and in nucleus dorsalis corporis geniculati lateralis. Very few serotonergic fibers were observed in nucleus paratenialis, nucleus gelatinosus, nucleus anterior medialis, nucleus medialis dorsalis, nucleus ventralis, nucleus ventralis pars dorsomedialis, or in nucleus corporis geniculati medialis. Serotonin immunoreactivity was also noted in a number of fiber bundles in the thalamic region. These include the fasciculus retroflexus, the fasciculus mamillothalamicus, the stria medullaris, and the stria terminalis. These results differ from those of previous descriptions of the serotonergic innervation of thalamic nuclei most notably in the midline nuclei and in the posterior complex. In this study the midline nuclei, nucleus rhomboideus, and nucleus reuniens were more densely innervated than had been described, and in the posterior complex a moderate, rather than sparse, innervation was observed. The more densely innervated nuclei of the anterior and lateral nuclear groups, nucleus lateralis dorsalis and nucleus anterior ventralis, also contained a greater number of labeled fibers than had been indicated.

The problem of dizziness and syncope in old age: transient ischemic attacks versus hypersensitive carotid sinus reflex.

In the elderly, a transient ischemic attack (TIA) and a hypersensitive carotid sinus reflex (HCSR) often co-exist and can pose a diagnostic challenge. Seven cases are presented. HCSR is a relative condition; besides increased irritability of the receptor or target organs, susceptibility of the nerve center to ischemia probably is induced by a slow heart rate or low blood pressure in any patient with pre-existing occlusive cerebrovascular disease. Dizziness and syncope of this type represent hemodynamic TIA in contrast to thromboembolic TIA. The carotid sinus massage test is recommended for differentiating the two types of TIA; the treatments differ. At present there is no uniform management that can be applied to either TIA or HCSR routinely. Therefore, treatment should be approached on an individual basis, keeping in mind the different pathophysiologic factors operating in the specific patient.

Response of rat superior salivatory units to chorda tympani stimulation.

Unit responses to chorda tympani stimulation in urethane anesthetized rats were characterized by response latency and frequency following ability. One hundred and fifty one units responded with constant latencies, mean: 16.9 msec, S.D.: 7.8 msec. Responses recorded from within the superior salivatory nucleus (SSN) had significantly longer latencies (18.8 +/- 6.8, n = 94) than those from surrounding areas (13.5 +/- 8.3, n = 50) (p less than 0.001). This difference was due to the higher incidence of responses with latencies between 2.7 and 10 msec outside of the SSN (44%) compared to SSN responses (8%). Ability to follow high frequency stimulation ranged from 2-550 Hz, and was the same for SSN neurons and those outside the nucleus. The population of responses localized to the SSN, with latencies greater than 10 msec and with high (greater than 100 Hz) frequency following, had a mean latency of 20.5 msec. The estimated conduction velocity for these presumed preganglionic, parasympathetic neurons is 0.85 M/sec +/- 0.25, significantly slower than that reported for similar responses in cats. The antidromic nature of these responses requires confirmation.

Localization of responses in the somatosensory thalamus of the rat.

In the monkey and cat electrophysiological studies have indicated that unit response characteristics can be correlated with anatomical divisions in the somatosensory thalamus. In the rat, however, one study has suggested that the ventrobasal (VB) and posterior (PO) complexes are not functionally distinct [7]. In the present study, therefore, an attempt was made to correlate anatomical localization and unit response characteristics in the rat. We found that in the VB complex, units responding to light touch (LT) were more common than in the PO complex (45% vs. 9%), while in the PO complex, nociceptive units were more numerous than in the VB complex (55% vs. 38%). In the VB complex LT units had a somatotopic organization; in the PO complex they did not. Within the VB complex all LT units in the ventral posteromedial nucleus had receptive fields on the head; most ventral posterolateral nucleus LT units had receptive fields on the body. These results indicate that a correlation between unit response characteristics and localization does exist in the rat.

Physiological stimulation enhances HRP marking of salivary neurons in rats.

Neurons of the superior salivary nucleus in rats have been labeled by retrograde transport of HRP injected into the lingual nerve. The nucleus is formed by a band of small, multipolar cells diagonally oriented in the lateral reticular formation of the caudal pons, just caudal to the root of the facial nerve. As time for transport of HRP was increased from 14 1/2 to 24 hr, the number of labeled cells increased exponentially along the curve, Y = 0.001 exp(0.51T), r = 0.995, to a maximum of 272 cells. Stimulating neuronal activity immediately after HRP injection, by swabbing the rat's mouth with 1% acetic acid, increased the number of labeled cells at 14 1/2 (p less than 0.05), 16, 18 and 20 (p less than 0.01) hr transport time. Counts of labeled cells in stimulated animals fell along a cumulative, normal distribution curve (ogive) with a mean at 18.2 hrs, S.D. 1.6 hr. Enhanced labeling of activated cells could be due to more rapid transport rates or to increased amounts of HRP transported.

Detection of acute infection/inflammation with Tc-99m labeled intact polyvalent human IgG.

Intact polyvalent human immune globulin (IgG) labeled with Tc-99m by a mild chemical method was investigated with animals infected with either S. aureus or E. coli in the thigh muscle. Focal infection was clearly visualized by Tc-99m IgG scintigraphy within 1 h postinjection. Tc-99m IgG appeared to be concentrated in the liver, spleen, kidneys and urinary bladder. It cleared rapidly via the kidneys resulting minimal of tissue background activity and high infection-to-normal organ ratios. At 24 h postinjection, the ratios of infectious lesion to blood, normal muscle and bone averaged 10:1, 23:1, and 24:1 for S. aureus infection vs 4:1, 9:1 and 9:1 for E. coli infection, respectively. Tc-99m labeled IgG also concentrated in terpentine-induced aseptic inflammatory lesion with a target-to-blood ratio of 4:1, bone 6:1 and normal muscle about 10:1. These findings suggest potential value of Tc-99m IgG as an imaging agent for the early detection of focal infection and inflammation.

Intramesenteric perforation of sigmoid diverticulitis with nonfatal venous intravasation.

Complications from barium enema are rare (0.035 per cent). A patient with venous intravasation during barium enema complicated by pylephlebitis and portal vein obstruction is the tenth to be reported on, the fourth to survive. This accident was associated with colon disease in eight of the patients studied, five of whom had diverticular disease.