Enhanced triglyceride clearance with intraperitoneal human acylation stimulating protein in C57BL/6 mice

Acylation stimulating protein (ASP), a novel adipocyte-derived autocrine protein, stimulates triglyceride synthesis and glucose transport in vitro in human and murine adipocytes. In vitro, chylomicrons increase ASP and precursor complement C3 production in adipocytes. Furthermore, in vivo, ASP production from human adipose tissue correlates positively with triglyceride clearance postprandially. The aim of the present study was to determine if intraperitoneally injected ASP accelerated triglyceride clearance in vivo after a fat load in C57Bl/6 mice. ASP increased the triglyceride clearance with a reduction of the triglyceride area under the curve over 6 h (AUC(0-6)) from 102.6 +/- 30.0 to 61.0 +/- 14.5 mg. dl(-1). h(-1) (P < 0.05), especially in the latter postprandial period (AUC(3-6); 56.2 +/- 18.0 vs. 24.9 +/- 8.9 mg. dl(-1). h(-1), P < 0.025). ASP also reduced plasma glucose both in the mice with accelerated plasma triglyceride clearance and in those with relatively delayed triglyceride clearance (P < 0.025). Therefore, ASP alters postprandial triglyceride and glucose metabolism.

Effects of eosinophil granule major basic protein on phosphatidylcholine secretion in rat type II pneumocytes

Eosinophils are involved in inflammatory diseases such as asthma. We previously reported that activated eosinophils increased the phosphatidylcholine (PC) secretion in primary cultures of rat type II pneumocytes. Increased PC secretion was confirmed to be partly mediated by superoxide anions released from activated eosinophils. However, the influence of eosinophil granule proteins on PC secretion is unknown at present. In this study, we determined whether eosinophil major basic protein (MBP) influences PC secretion. MBP dose dependently increased the PC secretion in rat type II pneumocytes without producing any cell damage. The MBP-induced increase in PC secretion was significantly reduced by preadministration of either H-7, a protein kinase inhibitor, or 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM, a chelator of intracellular Ca2+, but not by H-89, a protein kinase inhibitor. Our results suggest that the MBP-induced increase in PC secretion may provide mechanical stability and protect against lung atelectasis.

Modified hemoglobin-based blood substitutes: crosslinked, recombinant and encapsulated hemoglobin

Native hemoglobin in the form of stroma-free hemoglobin cannot be used as blood substitute. Hemoglobin has to be modified either molecularly or encapsulated. First generation molecularly modified ultrapure hemoglobins are now in clinical trial--some in Phase III. There are a number of these. Polyhemoglobin is formed by crosslinking hemoglobin molecules intermolecularly and intramolecularly. A crosslinked single hemoglobin molecule is formed by crosslinking hemoglobin intramolecularly. Recombinant hemoglobin from E.coli is formed by fusion of the subunits of each hemoglobin molecule. Conjugated hemoglobin is formed by crosslinking each hemoglobin molecule to soluble polymers. A second generation system formed by crosslinking hemoglobin-superoxide dismutase-catalase is being developed. A third generation hemoglobin-based blood substitute is based on microencapsulated hemoglobin, artificial red blood cells, that more closely resemble a complete red blood cell.

Ruminal undegradability of blood meal and effects of blood meal on ruminal and postruminal digestion in steers consuming vegetative orchardgrass hay

Four crossbred steers (360 +/- 3 kg) cannulated at the rumen and duodenum were used in a 4 x 4 Latin square design to examine the effects of supplemental blood meal (BM) on voluntary intake, digesta kinetics, ruminal fermentation, site and extent of digestion, and bacterial protein synthesis in steers fed vegetative orchardgrass hay (Dactylis glomerata L.). The levels of BM supplementation were 0, .07, .13, and .20 kg/d. Voluntary intake of OM (8.35 kg/d) was not significantly affected by BM supplementation. No significant effects of BM supplementation were detected for OM flow to the duodenum or digestion in the rumen or lower tract. However, total tract OM digestibility decreased 2.2 percentage units at .20 kg/d of BM intake (lower with vs without BM; P < .10). Total N intake and flow to the duodenum linearly increased (P < .10) with increasing BM level from 251 to 277 g/d and from 158 to 199 g/d, respectively. Ammonia N and bacterial N flows to the duodenum were not affected (P > .10) by BM supplementation. As a result, nonammonia N flow to the duodenum increased linearly (P < .10) with increasing BM supplementation. Ruminal escape N from BM was 83.5, 85.3, and 87.2% for .07, .13, and .20 kg/d of BM, respectively. Apparent bacterial efficiency and true bacterial efficiency were not affected (P > .10) by BM supplementation. Total amino acid and total essential amino acid flows to the duodenum were increased (P < .10) by dietary inclusion of BM. Duodenal flows of all essential amino acids except lysine and valine and of all nonessential amino acids except alanine and proline were increased (P < .10) by BM inclusion in the diet. In summary, supplementation with BM increased ruminal escape N and duodenal flows of total and most essential amino acids.

Delayed increase in blood pressure induced by spontaneously hypertensive rat plasma after high sodium intake

Plasma from spontaneously hypertensive rats (SHR) and from patients with essential hypertension has been suggested to contain a substance with a delayed pressor effect, parathyroid hypertensive factor (PHF), associated with salt-sensitive forms of hypertension. In order to study whether high sodium intake would increase plasma levels of PHF-like activity, determined by bioassay, SHR received either a high-sodium (2.6% Na in the chow) or a normal-sodium (0.3% Na) diet for 6 weeks. Intravenous injection of plasma from SHR on a high-sodium diet (6 ml/kg) to urethane-anaesthetized Wistar rats induced a delayed increase in mean arterial blood pressure 70-80 min after bolus injection. No delayed pressor effects could be demonstrated by plasma from SHR or Wistar rats on a normal-sodium diet. It is concluded that a factor with a delayed blood pressure-increasing effect appears to be present in plasma from SHR on a high-sodium diet but not in plasma from normotensive Wistar rats or SHR on a normal-sodium diet. Further studies to characterize this factor and its possible relation to salt-induced hypertension are warranted.

Alteration of the pharmacokinetics of small proteins by iodination

The pharmacokinetics of several proteins were investigated using two different assays. A 23 kDa recombinant protein fragment of bactericidal/permeability-increasing protein (rBPI23) was radiolabeled with 125I using Iodo-beads and administered rats. Plasma samples were collected and assayed for 125I-rBPI23 by radioactivity. In a separate experiment, rBPI23 was administered to rats and plasma samples were assayed for rBPI23 by ELISA. The clearance determined from plasma concentrations of 125I-rBPI23 measured by radioactivity was about 2.5-fold lower than that of rBPI23 determined by ELISA. In addition, the steady state volumes of distribution and mean residence times of 125I-rBPI23 measured by radioactivity were four-fold and 10-fold greater, respectively, compared to those measured by the ELISA method. By studying several proteins with a range of molecular weights, we found that the pharmacokinetics of proteins below about 60 kDa were different when assayed by radioactivity or ELISA, but those of proteins with molecular weights of at least 80 kDA revealed only minor differences. To determine which assay method yielded the correct plasma pharmacokinetic profile, rBPI23 was metabolically labeled with 35S-methionine and administered to rats, and plasma samples were assayed by radioactivity. The concentration-time profile assessed by this method was very close to that determined by ELISA. Exposing rBPI23 to chloramine-T (the oxidant used in the iodination process) and measuring its plasma concentration by ELISA revealed pharmacokinetics similar to those of the iodinated protein measured by radioactivity. In contrast, radiolabeling rBPI23 using iodinated Bolton-Hunter reagent (which avoids exposing the protein to oxidant), and measuring 125I-rBPI23 by radioactivity, yielded pharmacokinetics that were similar, although not identical, to the pharmacokinetics of rBPI23 measured by ELISA. Thus, our data suggest that directly iodinating low-molecular-weight proteins by oxidation procedures alters their clearance from the blood, preventing reliable determination of pharmacokinetic parameters.

Milk replacers with or without animal plasma for dairy calves

Holstein calves (n = 68; 40 heifers) at two locations were used to evaluate effects of the addition of plasma protein to milk replacers on growth, intake, feed efficiency, and fecal scores. Milk replacers were formulated to contain 20% CP and 20% fat. Plasma was added to milk replacers to provide 0 or 25% of CP and replaced whey protein. Calves were fed colostrum for 3 d and then milk replacer (10% of BW/d) for 56 d. Initial mean BW was 38.0 kg. Commercial calf starter was offered for ad libitum consumption throughout the study. Composition of the milk replacer had no effect on weekly BW, BW gain, intake of milk replacer or calf starter, efficiency of BW gain, or fecal scores. Mean BW gain during the 56-d study was 473 g/d, and mean BW at 56 d was 65.8 kg. Calves consumed 534 and 575 g of DM/d of milk replacer and calf starter, respectively, during the 56-d trial. Inclusion of plasma proteins at 25% of CP supported growth equal to that of whey protein.

Considerations of pool size in the manufacture of plasma derivatives

BACKGROUND

The pooling of human plasma from many donors for the purpose of manufacturing therapeutic proteins increases the risk of exposing recipients of these proteins to pathogens that may contaminate 1 or a few units included in the pool.

STUDY DESIGN AND METHODS

This risk is estimated for a range of manufacturing scales that would derive material from a varied number of donors and for a number of hypothetical infectious agents that may exist in the donor population over a wide range of prevalence. Risk is also calculated both for recipients of single doses of a plasma protein and for those who depend on long-term treatment with plasma derivatives.

RESULTS

Risk of exposure increases with pool size and the prevalence of the agent in question and accumulates with repeated treatments with material manufactured from different pools.

CONCLUSION

Reducing pool size would at best decrease this risk in proportion to the reduction in manufacturing scale. However, for individuals requiring repeated or continuous treatments, the risk of exposure to all but the rarest infectious agents would be only minimally affected, even by large reductions in manufacturing scale.

Eosinophil-fibroblast interactions. Granule major basic protein interacts with IL-1 and transforming growth factor-beta in the stimulation of lung fibroblast IL-6-type cytokine production

To test the hypothesis that eosinophil major basic protein (MBP) is an important regulator of fibroblast effector function, we characterized the effects of MBP on human lung fibroblast production of the IL-6-type cytokines, IL-6, IL-11, and leukemia inhibitory factor. Unstimulated fibroblasts did not produce substantial quantities of these cytokines, while IL-1 and TGF-beta(1) stimulated these cytokines in a potent fashion. MBP at doses < or = 44 micrograms/ml did not stimulate IL-6-type cytokine production. It did, however, interact in a synergistic, dose- and time-dependent fashion with rIL-1-alpha and TGF-beta(1) to further increase IL-6-type cytokine elaboration. These MBP-induced increases in cytokine production were associated with proportionate alterations in mRNA accumulation. In contrast, eosinophil-derived neurotoxin did not regulate fibroblast cytokine production, and MBP did not augment fibroblast granulocyte-macrophage-CSF, or type I collagen production, or fibroblast proliferation in this culture system. The effects of MBP could not be attributed to cell cytotoxicity or contaminants in the MBP preparations. They were, however, at least partially charge mediated, since heparin abolished the effects of MBP on IL-1-stimulated cells, and the surrogate cationic molecule poly-L-arginine mimicked the stimulatory effects of MBP on fibroblast IL-6-type cytokine elaboration. These studies demonstrate that MBP interacts in a synergistic fashion with rIL-1-alpha or TGF-beta(1) to further augment fibroblast IL-6-type cytokine production. They also demonstrate that this stimulation is pretranslationally mediated and due, in part, to the cationic nature of the MBP molecule. MBP regulation of fibroblast cytokine production may play an important role in the pathogenesis of eosinophilic disorders of the airway or other organs.

Value of feather meal in a molasses-based liquid supplement fed to yearling cattle consuming a forage diet

Hydrolyzed feather meal (FM) was compared to other sources of CP to determine its value as a protein source in a molasses-based liquid supplement. Ruminal N escape values (measured in situ) for FM, ring-dried blood meal, cottonseed meal, and soybean meal approximated reported values. Ruminal N escape value for catfish meal was lower than values reported for other fish meals. In two trials (194 d), 84 yearling heifers were allotted to 12 pastures (3 pastures/treatment) and fed one of four supplements (1.7 kg of DM.heifer-1.d-1) containing either molasses and urea; molasses, urea,and FM; molasses, urea, FM, and catfish meal; or molasses, urea, FM, and catfish oil. Heifers were exposed to bulls for 60 d. In two trials, 112 steers were allotted to 16 pastures (4 Pastures/treatment) and fed one of four supplements (1.7 kg of DM.steer-1.d-1) containing molasses and urea; molasses, urea and FM; molasses, urea, FM and ring-dried poultry blood meal; or molasses, urea, and poultry feathers and blood hydrolyzed together. In all trials, cattle fed molasses containing FM had faster gains (P < .05) and heifers had heavier live weights at breeding (P < .05) and higher pregnancy rates (P < .05) than cattle fed molasses and urea. Combining poultry blood with molasses, urea, and FM improved (P < .05) steer gains in one of two trials. Combining catfish meal with molasses, urea, and FM did not improve (P > .05) ADG of pregnancy rate of heifers. Combining catfish oil with molasses, urea, and FM increased (P < .05) ADG in one trial and blood cholesterol and live weight of heifers at breeding in both trials. It is concluded that protein feeds, such as FM, that contain a large portion of ruminally undegradable protein may provide much of the CP in liquid supplements fed to growing cattle consuming moderate-quality forage. Adding catfish oil to a liquid supplement may improve ADG and live weight of yearling heifers at breeding.

Polyarginine and eosinophil-derived major basic protein increase microvascular permeability independently of histamine or nitric oxide release

We tested the hypothesis that cationic peptides (polyarginine; poly-argn) and eosinophil-derived major basic protein (MaBP) increase permeability by stimulating the release of histamine and/or nitric oxide. We used intravital microscopy, clearance, and integrated optical intensity (IOI), using FITC-dextran 150 (FITC-dx 150) as a tracer, to evaluate changes in microvascular permeability in the hamster cheek pouch. Poly-argn at 1 microM (topical) increased the clearance of FITC-dx 150 from 610 to 3240 nl/60 min/g. In contrast, 1 microM polyglutamic acid (poly-glun; and anionic peptide) did not affect the clearance of FITC-dx 150 (605 nl/60 min/g). At 0.5 and 1.0 nM, poly-argn increased the clearance of FITC-dx 150 from 610 to 1722 and 2396 nl/60 min/g (P < 0.05). Similarly, 0.5 nM MaBP increased clearance from 591 +/- 38 to 1967 +/- 168 nl/60 min/g. L-NAME at 10(-4) M did not prevent the 0.5 nM MaBP-induced elevation in clearance (1784 +/- 350). Poly-argn at 1 nM increased net mean IOI by 21.5 +/- 7.2 units. This elevation was not inhibited by topical 10(-4) M L-NMMA (27.5 +/- 8.4). Using 0.5 nM poly-argn as agonist, we assayed suffusate samples for their histamine concentration using a competitive enzyme immunoassay and found no detectable histamine. Pyrilamine, an H1 antagonist, did not inhibit the 0.5 nM poly-argn-induced elevation in clearance of FITC-dx 150. We conclude that (1) cationic peptides and MaBP increase microvascular permeability and (2) the increase in microvascular permeability produced by low concentrations of poly-argn and by MaBP is independent of the release of histamine and does not require nitric oxide.

B/PI-derived synthetic peptides: synergistic effects in tethered bactericidal and endotoxin neutralizing peptides

Human neutrophil bactericidal protein (B/PI) is known for its ability to kill bacteria and to neutralize the action of endotoxin. Short linear peptides derived from residues 80-109 have been synthesized and their bactericidal and endotoxin neutralizing activities have been assayed. A series of 'walk-through' decapeptides, overlapping 3 to 4 residues, indicates that endotoxin neutralizing and partial bactericidal activities can be localized within the N- and C-terminal portions, respectively, of the 80-109 sequence. Bactericidal activity toward Pseudomonas aeruginosa was localized in central peptides of the walk-through series and greatest in peptide 90-99. By using longer peptides, residues 86-104 and 82-108, both bactericidal and endotoxin neutralizing activities are significantly enhanced. Bactericidal activity of peptide 82-108 is now only 6-fold less than that of parent B/PI and 9-fold more potent than peptide 86-104. The 82-108 peptide was 7-fold more active at endotoxin neutralization than 86-104 but showed less enhanced activity, being approx. 470-times less active than B/PI. Cyclized 82-108 peptide retained bactericidal activity but did not improve in capacity to neutralize endotoxin.

Effect of a recombinant N-terminal fragment of bactericidal/permeability-increasing protein (rBPI23) on cerebrospinal fluid inflammation induced by endotoxin

Endotoxin triggers the subarachnoid inflammation of gram-negative meningitis. This study examined the ability of a recombinant N-terminal fragment of bactericidal/permeability-increasing protein (rBPI23) to block endotoxin-induced meningitis in rabbits. Intracisternal (ic) injection of 10-20 ng of meningococcal endotoxin induced high cerebrospinal fluid (CSF) concentrations of tumor necrosis factor (TNF) and CSF pleocytosis and increased CSF lactate concentrations. ic administration of rBPI23 significantly reduced meningococcal endotoxin-induced TNF release into CSF (P < .005), lactate concentrations (P < .001), and CSF white blood cell counts (P < .01). No such effect was observed in animals receiving intravenous rBPI23. Concentrations of rBPI23 in CSF were high after ic administration but low or undetectable after systemic administration. Thus, high concentrations of rBPI23 can effectively neutralize meningococcal endotoxin in CSF, but low CSF concentrations after systemic administration currently limit its potential usefulness as adjunctive drug treatment in gram-negative meningitis.

Human lipopolysaccharide-binding protein potentiates bactericidal activity of human bactericidal/permeability-increasing protein

Human bactericidal/permeability-increasing protein (BPI) from neutrophils and a recombinant amino-terminal fragment, rBPI23, bind to and are cytotoxic for gram-negative bacteria both in vitro and ex vivo in plasma or whole blood. To function in vivo as an extracellular bactericidal agent, rBPI23 must act in the presence of the lipopolysaccharide-binding protein (LBP), which also binds to but has no reported cytotoxicity for gram-negative bacteria. LBP, which is present at 5 to 10 micrograms/ml in healthy humans and at much higher levels in septic patients, mediates proinflammatory host responses to gram-negative infection. On the basis of these previous observations, we have examined the effect of recombinant LBP (rLBP) on the bactericidal activity of rBPI23 against Escherichia coli J5 in vitro. Physiological concentrations of rLBP (5 to 20 micrograms/ml) had little or no bactericidal activity but reduced by up to approximately 10,000-fold the concentration of BPI required for bactericidal or related activities in assays which measure (i) cell viability as CFUs on solid media or growth in broth culture and (ii) protein synthesis following treatment with BPI. LBP also potentiated BPI-mediated permeabilization of the E. coli outer membrane to actinomycin D by about 100-fold but had no permeabilizing activity of its own. Under optimal conditions for potentiation, fewer than 100 BPI molecules were required to kill a single E. coli J5 bacterium.

[Idiopathic macular foramen: new aspects of staging and possible therapeutic concepts]

Idiopathic macular hole and its early stages raises one of the most fascinating subjects in retinal disease. In this review, we aim to summarize the current knowledge of pathogenesis, the recent classification and the strategies for therapy. Recent evidence strongly suggests tangential traction induced by a thin epiretinal membrane to be the main cause for idiopathic senile macular holes. A thickening of the epicortical vitreous membrane or the internal limiting membrane of the retina could be demonstrated in these cases. When such a precursor situation (stage I) is present, in many cases there will be a progression to a full thickness macular hole (stage II). Further traction usually causes an enlarging of the defect in these eyes and the classic appearance of macular holes (stage III-IV) can then be observed. The clinical appearance, the diagnosis and the strategies of treatment are discussed for all stages of idiopathic senile macular holes. Based on the deeper insight into macular hole development, prophylactic vitrectomy and removal of the epiretinal membrane in cases of stage I macular holes, has been considered in order to prevent a further progression of the disease. There is also evidence that in stages II-IV macular holes, a closure of the hole and a visual improvement can be gained by vitrectomy, removal of the epiretinal membrane and fluid-gas exchange. The additional application of biological modifiers (transforming growth factor-beta, human autologous serum or tissue glue) may enhance the adhesion of the detached retina and therefore lead to better anatomical and functional success rates. The results of the pilot studies are reviewed and the surgical techniques as well as the possible complications are discussed.

Effect of spray-dried porcine plasma protein on feed intake, growth rate, and efficiency of gain in mice

One hundred eight mice were weaned at 21 +/- 1 d and allotted to four dietary treatments: 1) control, 2) control + 4% spray-dried porcine plasma protein (SDPP), 3) control + 8% SDPP, and 4) control + 12% SDPP. Daily gain for males increased with increasing SDPP during wk 1 (P < .01), wk 2 (P < .01), and for the entire 3 wk (P < .01). Daily gain increased quadratically with increasing SDPP for females during wk 1 (P < .05). During the 3rd wk, ADG decreased for females with increasing SDPP (P < .05). Daily feed intake increased linearly (P < .01) with increasing SDPP in all periods. Gain-to-feed ratio (G/F) increased with increasing SDPP during wk 1 (P < .01) and for the first 2 wk (P < .05). During wk 3, G/F decreased with increasing SDPP level (P < .01). Gain-to-feed ratio of females responded quadratically to increasing SDPP during wk 1 (P < .05), whereas G/F of males increased linearly with increasing SDPP level. Gain-to-feed ratio for the entire trial was unaffected by treatment among females (P = .82) but increased linearly with increasing SDPP levels among males (P < .01). Liver weight increased quadratically with increasing SDPP levels for males (P < .05) and females (P < .05). Treatment effect on liver weight per kilogram BW.75 approached significance (P < .10) in females. Male liver weight/100 g BW and liver weight per kilogram BW.75 responded quadratically to increasing SDPP levels (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

A simple method for calculating component dilution during fluid resuscitation: the Leuven approach

STUDY OBJECTIVES

To test the reliability of the Leuven approach, a balance between oversimplified empiric rules and more complex calculations requiring the use of nomograms or computers, to determine blood component dilution during large transfusions. To present schemes for blood component dilution and stabilization, as well as four examples showing the practicability of the method.

DESIGN

Prospective study.

SETTING

Orthopedic operating rooms at a university hospital.

PATIENTS

108 patients undergoing total hip replacement with expected large blood loss.

INTERVENTIONS

Component concentrations were measured after patient arrival in the recovery room. Blood loss was followed clinically.

MEASUREMENTS AND MAIN RESULTS

Preset target component concentrations [hematocrit (Hct) 31%; total serum protein (TSP) 5.0 g/dl; prothrombin time (PT) 50%; blood platelets (BLPL) 50,000/microliters)] were compared with concentrations measured on arrival in recovery after dilution and stabilization, according to the transfusion scheme. Average blood loss was 3,226 +/- 1,600 ml (mean +/- SD). End component concentrations were Hct, 33.4% +/- 3.3%; TSP, 5.2 +/- 0.5 g/dl; PT, 52% +/- 12%; BLPL, 97,000/microliters. Hct and TSP showed significant (p < 0.05) but clinically unimportant differences from target concentrations. Possible reasons for variability in end concentrations are discussed.

CONCLUSION

The Leuven approach produces reliable blood component concentrations after extensive transfusions. It allows the clinician to decide for himself or herself, in accordance with general consensus and the patient's individual needs, when to stabilize blood components.

Human neutrophil bactericidal/permeability-increasing protein reduces mortality rate from endotoxin challenge: a placebo-controlled study

OBJECTIVES

To study the toxicology and pharmacology of the endotoxin-neutralizing agent, bactericidal/permeability-increasing protein.

DESIGN

Prospective, randomized, placebo-controlled laboratory study.

SETTING

Academic research laboratory.

SUBJECTS

CD-1 mice (n = 259); Sprague Dawley rats (n = 26); New Zealand White rabbits (n = 19).

INTERVENTIONS

Pharmacokinetics of intravenously injected bactericidal/permeability-increasing protein was assessed in mice. Toxicology was tested in mice and rats. Efficacy of intravenously administered bactericidal/permeability-increasing protein as an endotoxin-neutralizing agent was tested in mice, rats, and rabbits.

MEASUREMENTS AND MAIN RESULTS

Administration of a single 10-mg/kg bolus injection of bactericidal/permeability-increasing protein resulted in no alterations in hematologic, renal, or hepatic function, activity level, or weight gain in animals observed over a 7-day study period. A single bolus injection (10 mg/kg) of bactericidal/permeability-increasing protein protected 15 of 16 mice from a lethal endotoxin challenge (mortality rate 1/16 [6.25%]) compared with a 100% (16/16) mortality rate in the saline-treated controls (p < .001). Bactericidal/permeability-increasing protein administered up to 1 hr after endotoxin provided significant protection against lethal endotoxin challenge. Furthermore, bactericidal/permeability-increasing protein reduced the induration and dermal necrosis observed in the localized dermal Shwartzman reaction.

CONCLUSIONS

Bactericidal/permeability-increasing protein is a potent antiendotoxin that neutralizes endotoxin in vivo and prevents mortality in animal models of lethal endotoxemia.

Toxicity of an antitumor ribonuclease to Purkinje neurons

Purkinje cell toxicity is one of the characteristic features of the Gordon phenomenon, a syndrome manifested by ataxia, muscular rigidity, paralysis, and tremor that may lead to death (Gordon, 1933). Two members of the RNase superfamily found in humans, EDN (eosinophil-derived neurotoxin) and ECP (eosinophil cationic protein), cause the Gordon phenomenon when injected intraventricularly into guinea pigs or rabbits. We have found that another member of the RNase superfamily, an antitumor protein called onconase, isolated from Rana pipiens oocytes and early embryos, will also cause the Gordon phenomenon when injected into the cerebrospinal fluid of guinea pigs at a dose similar to that of EDN (LD50, 3-4 micrograms). Neurologic abnormalities of onconase-treated animals were indistinguishable from those of EDN-treated animals, and histology showed dramatic Purkinje cell loss in the brains of onconase-treated animals. The neurotoxic activity of onconase correlates with ribonuclease activity. Onconase modified by iodoacetic acid to eliminate 70% and 98% of the ribonuclease activity of the native enzyme displays a similar decrease in ability to cause the Gordon phenomenon. In contrast, the homologous bovine pancreatic RNase A injected intraventricularly at a dose 5000 times greater than the LD50 dose of EDN or onconase is not toxic and does not cause the Gordon phenomenon. A comparison of the RNase activities of EDN, onconase, and bovine pancreatic RNase A using three pancreatic RNA substrates demonstrates that onconase is orders of magnitude less active enzymatically than EDN and RNase A. Thus, another member of the RNase superfamily in addition to EDN and ECP can cause the Gordon phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomised controlled trial of plasma protein fraction versus dopamine in hypotensive very low birthweight infants

Around 20% of very low birthweight infants admitted to a neonatal intensive care unit become hypotensive within 24 hours of their admission. Standard treatment is either expansion of the circulating volume by the infusion of plasma protein fraction or by using dopamine to improve cardiac function. The purpose of this study was to investigate by a randomised controlled trial which was the most appropriate treatment. Thirty nine infants were randomised to receive either plasma protein fraction or dopamine as first line treatment if they became hypotensive within 24 hours of admission to the neonatal intensive care unit. Seventeen of 19 (89%) infants responded to dopamine, whereas only 9/20 (45%) responded to plasma protein fraction. The median dose of dopamine needed to increase the blood pressure to at least the 10th centile was 7.5 micrograms/kg/min and was infused for a median duration of 18 hours. These observations suggest that dopamine should be used earlier in the treatment of these infants than has previously been recommended.