Showing papers by "University of Texas Southwestern Medical Center published in 1982"
TL;DR: The generation of anti-Qa-1(b) CTL is under immune response (Ir) gene control because F(1) mice, obtained by crossing responder A/J with nonresponder B6.T1a(a) animals, generated CTL to the Qa-2 alloantigen when presented on B6 spleen cells.
Abstract: B6.T1a(a) (Qa-1(a)) mice that are primed in vivo and restimulated in vitro with Qa-1 congenic spleen cells from B6 (Qa-1(b)) animals are unable to generate anti-Qa-1(b) cytotoxic T lymphocytes (CTL). This nonresponsive pattern was observed regardless of the route of immunization or the time of testing in vitro. Although B6.T1a(a) mice are nonresponders to Qa-1(b) when presented on B6 cells, these mice can generate anti-Qa-1(b) CTL when primed in vivo with Qa-1 and H-Y alloantigens (females primed with B6 male cells) or Qa-1 and minor-H- alloantigens (primed with sex-matched A.BY cells). Therefore, the inability to generate anti-Qa-1(b) CTL is due to a lack of helper or accessory antigens on B6 immunizing cells obligatory during in vivo priming, rather than an absence of anti-Qa-1(b) CTL precursors (CTL-P). Demonstration that the additional determinants required during in vivo priming actually function as carrier or helper determinants was shown by the requirement for linked recognition of Qa-1 and the helper determinants (H-Y) in vivo, and the fact that H-Y was not present on susceptible target ceils. Animals primed in vivo with H-Y only could not generate anti-Qa-1 CTL activity when challenged in vitro with both Qa-1 and H-Y, indicating that recognition of the helper determinant causes in vivo priming of CTL-P rather than generating helper activity that might activate unprimed CTL-P in vitro. Whereas unprimed peripheral CTL-P require the presence of both Qa-1 (CTL) and H-Y (helper) determinants for successful in vivo priming, helper determinants were not required in vitro because primed CTL-P from B6.T1a(a) mice could be driven to CTL in vitro using sex-matched B6 stimulator cells. The generation of anti-Qa-1(b) CTL is under immune response (Ir) gene control because F(1) mice, obtained by crossing responder A/J with nonresponder B6.T1a(a) animals, generated CTL to the Qa-1(b) alloantigen when presented on B6 spleen cells. Progeny testing of backcross mice further demonstrated that the Ir gene(s) is linked to the H-2 complex. These data indicate that an H-2-linked Ir gene controls the recognition of helper determinants required for CTL priming in vivo. These helper determinants can be distinguished from CTL determinants and both must be recognized together for successful priming of CTL-P.
533 citations
TL;DR: It is established that the presence of annular skin lesions can serve as a cutaneous marker for a distinct subset of patients with lupus erythematosus who share similar clinical, serologic, and genetic features.
Abstract: We studied the autoimmune serologic features and histocompatibility antigen associations of 27 patients who had a widespread, nonscarring and often photosensitive form of histologically specific cutaneous lupus erythematosus. We designated this disorder as subacute cutaneous lupus erythematosus. Skin lesions from this disorder can be distinguished from scarring discoid lupus erythematosus lesions both on a morphologic and histopathologic basis. Antinuclear and anticytoplasmic antibodies (Ro or Ro and La) and circulating immune complexes were frequently present in patients with subacute cutaneous lupus erythematosus, whereas rheumatoid factor and anti-lymphocyte, anti-DNA, anti-nRNP, and anti-Sm antibodies were found less frequently. Patients having annular skin lesions represented a particularly homogeneous subgroup in which there was a striking concordance of anti-Ro antibodies and the HLA-DR3 phenotype. These studies clearly establish that the presence of these lesions can serve as a cutaneous marker for a distinct subset of patients with lupus erythematosus who share similar clinical, serologic, and genetic features.
430 citations
TL;DR: The results suggest that soluble factors produced by T cell lines and hybridomas can markedly influence both the class and subclass of Ig produced by B cells.
Abstract: Culturing BALB/c B cells for 6 d at low cell density in the presence of lipopolysaccharide (LPS) results in the appearance of a small number of IgG plaque-forming cells (PFC). The addition of supernatants from concanavalin A (Con A)-induced alloreactive (AKR anti-B6) long-term T cell lines (PK 7.1.1a and 7.1.2) or a T cell hybridoma (FS7-6.18) to LPS-treated B cells resulted in a marked increase in IgG PFC (3--10-fold higher than in cultures treated with LPS alone. The number of induced IgG PFC was not affected by removing IgG-bearing cells on the fluorescence-activated cell sorter, indicating that T cell-derived B cell differentiation factor enhances isotype switching of sIgG- cells, rather than selecting and expanding pre-existing subpopulations of sIgG+ cells. We also investigated the subclass of IgG produced in the absence or presence of T cell factors and found that PK 7.1.1a, PK 7.1.2, and FS7-6.18 supernatants selectively increased IgG1 production. Several other T cell supernatants containing a variety of lymphokines had no effect, suggesting that PK 7.1.1a, PK 7.1.2, and FS7-6.18 lines produce factor(s) that can specifically enhance the recovery of IgG secreting cells in culture in the presence of LPS. These factors, which we have termed B cell differentiation factors, are different from interleukin 1, interleukin 2, T cell-replacing factor, colony-stimulating factor, macrophage-activating factor, and immune interferon. Our results suggest that soluble factors produced by T cell lines and hybridomas can markedly influence both the class and subclass of Ig produced by B cells.
357 citations
290 citations
TL;DR: Fibroblasts from a child with the phenotype of homozygous familial hypercholesterolemia showed a disruption in receptor processing, which may be due to the simple addition of N-linked oligosaccharide chains.
238 citations
TL;DR: It is concluded that the rabbit liver normally has at least two genetically distinct lipoprotein uptake mechanisms, both of which recognize chylomicron remnants: (i) the LDL receptor and (ii) a specific chylomaticron remnant uptake mechanism that is not measured adequately by current in vitro membrane binding assays.
Abstract: Homozygous Watanabe hereditary hyperlipidemic (WHHL) rabbits have a near-complete deficiency of low density lipoprotein (LDL) receptors in liver and other tissues. As a result, these rabbits clear LDL from plasma at an abnormally slow rate. In the current studies we show that WHHL rabbits clear chylomicrons from plasma at a normal rate. Chylomicrons are cleared by a two-step process: (i) hydrolysis of triglycerides in extrahepatic tissues to yield cholesteryl ester-rich remnant particles and (ii) rapid uptake of the remnants by liver. Normal and WHHL rabbits were given intravenous injections of rat chylomicrons labeled either in the lipid portion with [3H]cholesterol and [14C]palmitate or in the protein portion with [125]iodine. All radiolabeled components were removed from plasma at comparable rates in normal and WHHL rabbits. Comparable amounts of radioactivity accumulated in livers of animals from both genotypes. In vitro assays showed that liver membranes from WHHL rabbits were markedly deficient in the binding of 125I-labeled chylomicron remnants as well as 125I-labeled LDL, implying that chylomicron remnants can bind to the hepatic LDL receptor. We conclude that the rabbit liver normally has at least two genetically distinct lipoprotein uptake mechanisms, both of which recognize chylomicron remnants: (i) the LDL receptor and (ii) a specific chylomicron remnant uptake mechanism that is not measured adequately by current in vitro membrane binding assays. WHHL rabbits possess a normal chylomicron remnant uptake mechanism that allows them to clear chylomicrons from plasma at a rapid rate despite their genetic deficiency of LDL receptors.
236 citations
TL;DR: A line of Chinese hamster ovary cells with a 500-fold increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the membrane-bound enzyme that controls cholesterol synthesis and also for studies of the synthesis and degradation of smooth ER is developed.
Abstract: We have developed a line of Chinese hamster ovary cells with a 500-fold increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the membrane-bound enzyme that controls cholesterol synthesis. This line, designated (UT-1, was obtained by stepwise adaptation of cells to growth in increasing concentrations of compactin, a competitive inhibitor of reductase. Reductase accounts for approximately 2% of total cell protein in UT-1 cells, as calculated from enzyme specific activity and by immunoprecipitation of reductase after growth of cells in [35S]methionine. After solubilization in the presence of the protease inhibitor leupeptin and electrophoresis in NaDodSO4/polyacrylamide gels, reductase subunits from UT-1 cells were visualized by immunoblotting as a single band (Mr = 62,000). To accommodate the increased amounts of reductase, UT-1 cells developed marked proliferation of tubular smooth endoplasmic reticulum (ER) membranes, as revealed by immunofluorescence and electron microscopy. The ER tubules were packed in crystalloid hexagonal arrays. When UT-1 cells were incubated with low density lipoprotein, reductase activity was suppressed by 90% in 12 hr and the crystalloid ER disappeared. UT-1 cells should be useful for studies of the regulation of reductase and also for studies of the synthesis and degradation of smooth ER.
230 citations
TL;DR: The results suggest that group IV muscle afferents are primarily responsible for causing the reflex increases in cardiovascular function evoked by injecting capsaicin into the arterial supply of the skinned hindlimb of dogs.
Abstract: Capsaicin, injected into the arterial supply of the skinned hindlimb of dogs, evokes reflex increases in cardiovascular function. Moreover, the cardiovascular reflexes evoked by capsaicin are very similar to those evoked by static exercise. The afferent fibers initiating these reflex increases have not been identified electrophysiologically, although their endings are believed to be located in skeletal muscle. We have, therefore, attempted to determine which afferent fibers are stimulated by capsaicin. In anesthetized dogs, we recorded impulses from afferent fibers with endings in either the gastrocnemius or gracilis muscles and injected capsaicin (10-30 microgram/kg) into the abdominal aorta. Capsaicin stimulated 24 of 34 group IV (C fiber) endings, but only 5 of 19 group III (A delta fiber) endings. By contrast, bradykinin (0.5-1.5 microgram/kg) stimulated 17 of 33 group IV endings and 9 of 19 group III endings. Impulse activity for the 24 group IV afferents stimulated by capsaicin increased from 0.7 +/- 0.1 to a peak of 9.3 +/- 1.4 imp/sec. Firing started 6 +/- 1 seconds after injection and remained above control levels for 24 +/- 5 seconds. Capsaicin had no significant effect on the firing rate of 30 group I and II muscle afferents. Our results suggest that group IV muscle afferents are primarily responsible for causing the reflex increases in cardiovascular function evoked by injecting capsaicin into the arterial supply of the skinned hindlimb of dogs. Moreover, capsaicin is likely to be a useful pharmacological tool with which to determine the reflex autonomic effects caused by stimulation of group IV muscle afferents.
218 citations
TL;DR: The mechanism of internalization of LDL in human fibroblasts is described, using LDL that was covalently coupled to ferritin as a specific electron microscopic probe, and it was shown that LDL binds to receptors that are associated with coated pits on the cell surface.
212 citations
TL;DR: It is concluded that in normal subjects, Na-induced renal hypercalciuria is accompanied by increased 1,25-(OH)2D synthesis and enhanced intestinal Ca absorption and mediation by PTH is suggested.
Abstract: Earlier studies have shown that an oral sodium (Na) load may induce hypercalciuria in previously normocalciuric subjects and may also increase intestinal calcium (Ca) absorption. To probe the cause of the increased intestinal Ca absorption, we simultaneously measured parathyroid function, serum 1,25-dihydroxyvitamin D [1,25-(OH)2D], and fractional intestinal 47Ca absorption before and after a salt load. Eleven normal subjects and two patients with postsurgical hypoparathyroidism were placed on a 10 meq Na, 400 mg Ca per day diet for 10 days, followed by another 10-day period in which the same diet was supplemented by 240 meq Na daily. Measurements were performed on the final 3 days of each phase. In the normal subjects, urinary Na excretion increased from 7 +/- 2 to 226 +/- 8 meq/day (mean +/- SEM), urinary Ca rose from 110 +/- 14 to 167 +/- 16 mg/day, serum parathyroid hormone (PTH) increased from 20 +/- 1 to 22 +/- 1 muleq/ml, serum 1,25-(OH)2D rose from 38 +/- 4 to 51 +/- 7 pg/ml, and fractional intestinal 47Ca absorption increased from 0.39 +/- 0.03 to 0.49 +/- 0.03 (P less than 0.05 for all changes). Serum Ca corrected for total protein did not change (9.9 +/- 0.1 to 9.8 +/- 0.1 mg/dl). The patients with hypoparathyroidism who were maintained on vitamin D therapy also showed increases in urinary Na (20 +/- 12 to 245 +/- 11 meq/day) and urinary Ca (271 +/- 48 to 305 +/- 43; P less than 0.05). However, there were no increases in serum PTH (13 +/- 1 to 11 +/- 1 muleq/ml), serum 1,25-(OH)2D (44 +/- 1 to 40 +/- 6 pg/ml), or intestinal Ca absorption (0.41 +/- 0.03 to 0.42 +/- 0.05). Corrected serum Ca decreased from 9.4 +/- 0.2 to 8.6 +/- 0.2 mg/dl. We conclude that in normal subjects, Na-induced renal hypercalciuria is accompanied by increased 1,25-(OH)2D synthesis and enhanced intestinal Ca absorption. Since this adaptive mechanism did not occur in two patients with hypoparathyroidism, mediation by PTH is suggested.
210 citations
TL;DR: In rabbits, the LDL receptor mediates the rapid removal of VLDL and IDL from plasma, and a deficiency of LDL receptors leads to an enhanced conversion of V LDL to LDL, indicating a massive increase of plasma LDL levels in homozygous WHHL rabbits.
Abstract: Rabbit livers express two genetically distinct receptors for plasma lipoproteins: (i) the low density lipoprotein (LDL) receptor and (ii) the chylomicron remnant receptor. In homozygous Watanabe-heritable hyperlipidemic (WHHL) rabbits, an animal model for human familial hypercholesterolemia, LDL receptors are genetically deficient, but chylomicron remnant receptors are normal. Hence, WHHL rabbits clear LDL from the circulation at an abnormally slow rate, but they clear chylomicron remnants at a normal rate. The current studies show that WHHL rabbits clear 125I-labeled very low density lipoprotein (VLDL) and its metabolic product, intermediate density lipoprotein (IDL), from plasma at a markedly decreased rate. The impaired clearance is due to a profound decrease in the rate of uptake of 125I-labeled VLDL and 125I-labeled IDL by the liver. Because of its rapid clearance in normal rabbits, only a fraction of the 125I-labeled apoprotein B component of VLDL is converted to LDL. In WHHL rabbits, the impaired clearance of VLDL leads to a markedly increased conversion of 125I-labeled apoprotein B from VLDL to LDL. These results indicate that: (i) in rabbits, the LDL receptor mediates the rapid removal of VLDL and IDL from plasma, and (ii), a deficiency of LDL receptors leads to an enhanced conversion of VLDL to LDL. The combination of overproduction and impaired plasma clearance of LDL, both resulting from a single gene mutation in the LDL receptor, leads to a massive increase of plasma LDL levels in homozygous WHHL rabbits.
TL;DR: Thirty supracondylar and intercondylar fractures of the femur in twenty-eight patients were reduced and stabilized with ASIF techniques and an extensile surgical exposure with elevation of the tibial tuberosity was used successfully in eight limbs to facilitate the exposure of multiplanar intra-articular fractures.
Abstract: Thirty supracondylar and intercondylar fractures of the femur in twenty-eight patients were reduced and stabilized with ASIF techniques. After an average follow-up of 28.5 months, the results were good or excellent in twenty-four limbs. An extensile surgical exposure with elevation of the tibial tuberosity was used successfully in eight limbs to facilitate the exposure of multiplanar intra-articular fractures. Close attention to the surgical details is necessary to avoid the potential complications of this approach.
Journal Article•
TL;DR: Severe hyperkalemia, acute renal failure, rhabdomyolysis and disseminated intravascular coagulation often dominate the course of patients with exertional heat stroke but are uncommon in those with classical heat stroke.
TL;DR: A positive correlation existed between LC2 phosphate content and potentiation of peak twitch tension in both types of muscles, suggesting a physiological function for LC2 phosphorylation.
Abstract: Phosphorylation of the myosin light chain 2 (LC2) subunit was examined in rat fast-twitch and slow-twitch skeletal muscles in response to repetitive stimulation at 23 and 35 degrees C and on incubation of fast-twitch skeletal muscle with isoproterenol. After a 1-s tetany at 35 degrees C, LC2 phosphate content in extensor digitorum longus muscle increased rapidly and transiently from 0.21 to 0.51 mol phosphate/mol LC2. This pattern of phosphorylation was similar to that observed at 23 degrees C. Increases in LC2 phosphate content were dependent on the frequency and duration of stimulation. In soleus muscle LC2 phosphate content was minimal following a 1-s tetany but increased markedly following more prolonged tetanies. On incubation of extensor digitorum longus muscle with isoproterenol (20 microM), LC2 phosphate content did not change, whereas phosphorylase a levels increased. A positive correlation existed between LC2 phosphate content and potentiation of peak twitch tension in both types of muscles, suggesting a physiological function for LC2 phosphorylation.
TL;DR: The immunoblotting technique should prove useful in analyzing structural alterations, if they exist, in LDL receptors from other subjects with cross-reacting material-positive forms of familial hypercholesterolemia.
TL;DR: The hypercalcemia of sarcoidosis responds to short term steroid treatment with an associated reduction in serum 1,25-dihydroxycholecalciferol [1,25-(OH)2D] and intestinal Ca absorption and the response to steroids in the patients with PHPT was variable.
Abstract: The hypercalcemia of both sarcoidosis and primary hyperparathyroidism (PHPT) has been associated with increased serum 1,25-dihydroxycholecalciferol [1,25-(OH)2D] and enhanced intestinal absorption of Ca. The hypercalcemia of sarcoidosis responds to short term steroid treatment with an associated reduction in serum 1,25-(OH)2D and intestinal Ca absorption. To gain insight into the lack of suppression of the hypercalcemia of PHPT by steroids, 10 patients with PHPT were studied while kept on a constant diet for 15 days. Days 1– 3 represented the equilibration period, days 4–7 constituted the control period, and days 8–15 made up the treatment period (prednisolone, 50 mg daily in 4 divided doses). In response to prednisolone, patients with PHPT had significant increases in serum Ca [11.5 ± 0.3 to 11.9 ± 0.4 (SEM) mg/ dl[, serum P (2.4 ± 0.2 to 3.1 ± 0.1 mg/dl), and urinary Ca (393 ± 55 to 529 ± 53 mg/day; P < 0.005 for each). The response of serum 1,25-(OH)2D to steroids in the patients with PHPT was variable...
TL;DR: The initial rate of activation of the regulatory component of adenylate cyclase by toxin was found to be linearly related to the amount of factor present in the reaction, which has allowed the quantitation and partial purification of the factor from turkey erythrocyte membranes.
TL;DR: It is important to employ chelation therapy prior to any operative intervention to reduce the mobilization of lead from bone during or following the surgical procedure.
Abstract: Lead intoxication (plumbism) from retained bullets has rarely been reported but may be fatal if unrecognized. Bullets lodged within joint spaces or pseudocysts are more likely to develop this complication, although patients with retained missiles in other locations may also be at risk. Subtle findings such as the occurrence of unexplained anemia, abdominal colic, nephropathy, or neurologic deterioration in patients with retained missiles may suggest consideration of plumbism. An intercurrent metabolic stress such as infection, endocrinopathy, or alcoholism may be a precipitating factor. Among the various diagnostic studies available, mass spectrometric stable isotope dilution analysis may be the most reliable. It is important to employ chelation therapy prior to any operative intervention. This will reduce the mobilization of lead from bone during or following the surgical procedure.
TL;DR: The data suggest that the increased numbers of β-adrenergic receptors in canine LV ischemic tissue are capable of translating physiological responses when they are activated with an appropriate agonist in vivo.
Abstract: In the present study, we evaluated the physiological responsiveness of the increased numbers of beta-adrenergic receptors in ischemic canine myocardium to in vivo stimulation by (-)-isoproterenol and epinephrine. After 1 hour of temporary proximal left anterior descending coronary artery occlusion and during a 15-minute period of reflow, dogs received (1)-isoproterenol intravenously at a rate sufficient to increase their heart rates 20--40 beats/min. Following the infusion of isoproterenol, myocardial tissue was obtained from the LV ischemic and nonischemic regions for measurement of beta-adrenergic receptor numbers, cyclic AMP content, and phosphorylase b to a conversion. beta-Adrenergic receptor numbers were significantly increased in the left ventricular (LV) ischemic tissue. The administration of (-)-isoproterenol was associated with significant increases in cyclic adenosine monophosphate content and phosphorylase b to a conversion in the LV ischemic tissue. Also, the administration of (-)-epinephrine significantly increased the phosphorylase b to a conversion in ischemic tissue over the nonischemic tissue and this conversion was blocked by pretreatment with (+/-)-propranolol. These data suggest that, in this experimental model, the increased numbers of beta-adrenergic receptors in canine LV ischemic tissue are capable of translating physiological responses when they are activated with an appropriate agonist in vivo.
TL;DR: The identification of the major organic-soluble metabolites of arachidonic acid is reported, which are the 5,6,8,9,11,12, and 14,15-epoxy-eicosatrienoic acid derivatives of archidonic Acid.
TL;DR: It is concluded that androgen resistance may be the cause of a significant fraction (40% or more) or idiopathic male infertility due to azoospermia or severe oligOSpermia, and that this disorder may not be manifested by a functional defect in the pituitary-testicular axis.
Abstract: To ascertain the frequency of androgen resistance as the cause of male infertility and to determine whether endocrine abnormalities are a universal feature of the disorder, we measured the androgen receptor in fibroblasts cultured from the genital skin of 28 unrelated phenotypically normal men with idiopathic azoospermia or oligospermia. The amounts of androgen receptor were compared with those in genital skin fibroblasts from a variety of other subjects, including 10 men with azoospermia of known cause, 5 normal men, 28 subjects with disorders of androgen formation of metabolism of known cause, and 28 persons with documented disorders of the androgen receptor (testicular feminization and Reifenstein syndrome). The mean androgen receptor Bmax (amount of high affinity binding) was 12 fmol/mg protein or greater in 10 infertile men with azoospermia of known cause and in 6 infertile men with mild oligospermia. In fibroblasts from 1 to 4 individuals with severe oligospermia of unknown cause (less than 1 million/ml) and 8 of 18 subjects with idiopathic azoospermia, the androgen receptor Bmax was less than 12 fmol/mg protein. The mean value in these 9 men was not significantly different from that in subjects with testicular feminization or Reifenstein syndrome. Serum concentrations of testosterone and LH were normal in 6 of these 9 infertile men, and plasma production rates of testosterone were elevated in only 2 of the 6 men studied in whom the Bmax values in genital skin fibroblasts were less than 12 fmol/mg protein. We conclude that androgen resistance may be the cause of a significant fraction (40% or more) or idiopathic male infertility due to azoospermia or severe oligospermia, and that this disorder may not be manifested by a functional defect in the pituitary-testicular axis.
TL;DR: The putative transmembranal exon is strikingly similar to that of the μ chain and the internal cytoplasmic exon codes for exactly the same two amino acids, valine and lysine.
Abstract: We have sequenced secreted and membrane terminal exons of the murine immunoglobulin δ chain. The putative transmembranal exon is strikingly similar to that of the μ chain and the internal cytoplasmic exon codes for exactly the same two amino acids, valine and lysine. A third potential exon was found between S and M exons that could code for yet another hydrophilic carboxyl terminus termed δX.
TL;DR: The results indicate that the traffic of Langerhans cells to the skin can be extremely dynamic, especially when the epidermal surface has been markedly disturbed, and imply that, under normal circumstances, large numbers of Langers cells can be mobilized readily from an available pool of precursors.
Abstract: To explore the relationships among Ia antigen expression, epidermal Langerhans cells, and the immunogenicity of skin allografts, cellophane tape-stripping was used in H-2 congenic and recombinant mice of defined immunogenetic disparity. Tape-stripping of murine abdominal wall skin achieved almost complete depletion of epidermal Langerhans cells within a few hours of application, as measured by cell surface ATPase and expression of Ia antigens. Tape-stripping also reduced, to a considerable degree (but not absolutely), the Ia immunogenicity of skin allografts prepared from stripped surfaces. No comparable reduction in immunogenicity of class I major histocompatibility determinants was observed, suggesting that Langerhans cells are relatively unimportant in the presentation of H-2K antigens in skin grafts. Langerhans cells reappear within 24 h of tape-stripping to anatomically intact skin, but are detectable in orthotopically grafted only after the graft has been in residence for 4 d, i.e., shortly after it has acquired a blood supply. Repopulating Langerhans cells at that time and thereafter are exclusively of host origin. These results indicate that the traffic of Langerhans cells to the skin can be extremely dynamic, especially when the epidermal surface has been markedly disturbed, and the data imply that, under normal circumstances, large numbers of Langerhans cells can be mobilized readily from an available pool of precursors.
TL;DR: Data indicate that the primary translation product of reductase mRNA is a 90,000-dalton protein and that LDL suppresses the reduct enzyme in UT-1 cells by drastically reducing the level of its mRNA.
Abstract: A recombinant plasmid containing a 1.2-kilobase cDNA for 3-hydroxy-3-methylglutaryl coenzyme A reductase was isolated from a cDNA library prepared from UT-1 cells, a clone of Chinese hamster ovary cells that has markedly elevated reductase activity. This plasmid, designated pRed-10, was identified by differential colony hybridization and hybrid-selected mRNA translation. The mRNA that hybridized to pRed-10 directed the synthesis in vitro of a 90,000-dalton protein that was immunoprecipitated by an antireductase antibody. The same 90,000-dalton protein was immunoprecipitated when UT-1 cells were pulse labeled with [35S]methionine in vivo and rapidly solubilized with boiling NaDodSO4. By blot hybridization, pRed-10 hybridized to mRNAs of 4.2 and 4.7 kilobases in UT-1 cells. Both mRNAs were reduced to undetectable levels when low density lipoprotein, a suppressor of the reductase, was present in the culture medium. These data indicate that the primary translation product of reductase mRNA is a 90,000-dalton protein and that LDL suppresses the reductase in UT-1 cells by drastically reducing the level of its mRNA.
TL;DR: It is concluded that extraction of S. typhimurium LPS with phenol does not significantly alter the biological activity or the lipoprotein binding behavior of the LPS and that the in vivo fates of phenol-extracted and membrane fragment LPS are essentially identical.
Abstract: Although phenol-extracted gram-negative bacterial lipopolysaccharides (LPS) have been used to study the properties of endotoxins for many years, nothing is known about the behavior of native (unextracted) LPS in vivo. Accordingly, we have compared extracted and native forms of LPS with regard to their biological activity, their ability to bind to plasma high density lipoproteins (HDL), and their fate after intravenous injection into rats. The LPS of Salmonella typhimurium G-30 were labeled with [(3)H]galactose, and whole bacteria, bacterial outer membranes, outer membrane fragments (harvested from the bacterial culture supernatant), and phenol extracts of the bacteria were prepared. After defining the LPS, phospholipid, and protein composition of these preparations, we compared the activity of the LPS in phenol extracts and membrane fragments in two assays. In both the limulus lysate assay and the rabbit pyrogen test, the LPS in phenol extracts were slightly more potent than the LPS in membrane fragments. We next studied the ability of the LPS in each preparation to bind to rat lipoproteins in vitro, and each preparation was then injected intravenously into rats for measurements of LPS-HDL binding and tissue uptake in vivo. Two patterns of lipoprotein binding were observed. Less than 25% of the LPS in both outer membranes and whole bacteria bound to HDL in vitro. When the outer membranes and whole bacteria were injected into rats, their LPS again bound poorly to HDL and they were rapidly removed from plasma into the liver and spleen. In contrast, >50% of the LPS in both culture supernatant membrane fragments and phenol-water extracts bound to HDL in vitro. When these preparations were injected into rats, approximately 50% of the LPS in the membrane fragments and phenol-water extracts bound to HDL and remained in the plasma over the 10-min study period. Moreover, the LPS in these preparations accumulated in the ovary and the adrenal gland, two tissues that use HDL-cholesterol for hormone synthesis. Binding to HDL thus greatly influenced the plasma half-life and tissue uptake of both extracted and native LPS. We conclude that extraction of S. typhimurium LPS with phenol does not significantly alter the biological activity or the lipoprotein binding behavior of the LPS and that the in vivo fates of phenol-extracted and membrane fragment LPS are essentially identical. The results thus provide important support for many previous studies that have used phenol-extracted LPS to mimic the activities of native LPS in vivo. However, the only native LPS that resembled the behavior of extracted LPS were the LPS that had been shed from the bacteria in fragments of membrane that had reduced amounts of protein and phospholipid. Removal of LPS from other outer membrane constituents, whether by chemical extraction or by a natural process of surface shedding, thus alters the behavior of the LPS; the most important feature of this alteration appears to be the ability of these LPS to bind readily to HDL.
TL;DR: Nine patients with triradiate physeal-cartilage injury were classified according to the degree of displacement and the probable type of growth-plate disruption, and the prognosis is dependent on the age of the patient at the time of injury and on the extent of chondro-osseous disruption.
Abstract: Traumatic disruption of the acetabular triradiate physeal cartilage is an infrequent injury. When it occurs during adolescence, subsequent growth changes in acetabular morphology and congruency of the hip joint are unlikely. However, in younger children, especially those who are less than ten years old, acetabular growth abnormality is a frequent complication of this injury and may result in a shallow acetabulum similar to that seen in patients with congenital disease of the hip. By the time of skeletal maturity, disparate growth increases the incongruency of the hip joint and may lead to progressively more severe subluxation of the hip. Acetabular reconstruction may be necessary to correct the gradual subluxation of the femoral head. Variable irregularities of growth at the proximal end of the femur also may occur. In this series, nine patients with triradiate physeal-cartilage injury were classified according to the degree of displacement and the probable type of growth-plate disruption. Two main patterns of injury occurred. The first was a shearing type-1 or 2 growth-mechanism injury, with central displacement of the distal portion of the acetabulum. This injury pattern seems to have a favorable prognosis for continued normal acetabular growth, although premature closure of the triradiate physes may occur. The other pattern appeared to be a crushing type-5 growth-mechanism injury. This type has a poor prognosis, with premature closure of the triradiate physes occurring secondary to the formation of a medial osseous bridge. In either pattern, the prognosis is dependent on the age of the patient at the time of injury and on the extent of chondro-osseous disruption.
TL;DR: Prolonged remissions were induced in mice bearing advanced BCL1 tumors by the combined approach of nonspecific cytoreductive therapy and administration of a tumor-reactive immunotoxin and the inability to transfer tumor to recipients might indicate that the donor animals were tumor free.
Abstract: Prolonged remissions were induced in mice bearing advanced BCL1 tumors by the combined approach of nonspecific cytoreductive therapy and administration of a tumor-reactive immunotoxin. Thus, the vast majority of the tumor cells (approximately 95%) were first killed by nonspecific cytoreductive therapy using total lymphoid irradiation (TLI) and splenectomy. The residual tumor cells were then eliminated by intravenous administration of an anti-delta immunotoxin. In three of four experiments, all animals treated in the above fashion appeared tumor free 12-16 wk later. In one experiment, blood cells from the mice in remission were transferred to normal BALB/c recipients, and the latter animals have not developed detectable tumor for the 6 mo of observation. Because 1-10 adoptively transferred BCL1 cells will cause tumor in normal BALB/c mice by 12 wk, the inability to transfer tumor to recipients might indicate that the donor animals were tumor free. In the remainder of the animals treated with the tumor-reactive immunotoxin there was a substantial remission in all animals, but the disease eventually reappeared. In contrast, all mice treated with the control immunotoxin or antibody alone relapsed significantly earlier (3-4 wk after splenectomy).