Equine laminitis: ultrastructural lesions detected 24-30 hours after induction with oligofructose

REASONS FOR PERFORMING STUDY

The pathology of equine laminitis has been well-documented 48 h after dosing with oligofructose when clinical lameness and lamellar disintegration is well advanced. Further analysis of the earliest lesions, by collecting lamellar samples at the first sign of foot lameness after oligofructose dosing is required in order to increase understanding of the disease.

OBJECTIVES

To investigate lamellar epidermal hemidesmosome damage and basement membrane dysadhesion by transmission electron microscopy (TEM).

METHODS

Eight clinically normal, mature Standardbred horses were divided randomly into 2 groups of 4. The treatment group were dosed with oligofructose (10 g/kg bwt) and subjected to euthanasia when shifting weight from one foot to other commenced and at the first sign of lameness during walking and turning. This occurred at 24 h in 3 horses and 30 h in one. The sham treatment control group were dosed with water and subjected to euthanasia after 48 h. Lamellar tissues of the front feet were harvested and processed for ultrastructural study using TEM.

RESULTS

Examination by TEM showed excessive waviness of the basement membrane zone and pointed tips of some secondary epidermal lamellae, an ultrastructural lesion typical of laminitis. The average number of hemidesmosomes/microm of basement membrane was decreased and their distance from the centre of the lamina densa of the basement membrane was increased.

CONCLUSIONS

Laminitis lesions are detectable 24 h after oligofructose administration.

POTENTIAL RELEVANCE

Hindgut events occurring in the first 24 h after dosing have begun the destruction of the hoof lamellar interface. Prevention and treatment strategies should precede lameness if they are to be efficacious.

Epstein-Barr virus BNRF1 protein allows efficient transfer from the endosomal compartment to the nucleus of primary B lymphocytes

Epstein-Barr virus (EBV) is a tumor virus with marked B lymphotropism. After crossing the B-cell membrane, the virus enters cytoplasmic vesicles, where decapsidation takes place to allow transfer of the viral DNA to the cell nucleus. BNRF1 has been characterized as the EBV major tegument protein, but its precise function is unknown. We have constructed a viral mutant that lacks the BNRF1 gene and report here its in vitro phenotype. A recombinant virus devoid of BNRF1 (DeltaBNRF1) showed efficient DNA replication and production of mature viral particles. B cells infected with the DeltaBNRF1 mutant presented viral lytic antigens as efficiently as B cells infected with wild-type or BNRF1 trans-complemented DeltaBNRF1 viruses. Antigen presentation in B cells infected with either wild-type (EBV-wt) or DeltaBNRF1 virus was blocked by leupeptin addition, showing that both viruses reach the endosome/lysosome compartment. These data were confirmed by direct observation of the mutant virus in endosomes of infected B cells by electron microscopy. However, we observed a 20-fold reduction in the number of B cells expressing the nuclear protein EBNA2 after infection with a DeltaBNRF1 virus compared to wild-type infection. Likewise, DeltaBNRF1 viruses transformed primary B cells much less efficiently than EBV-wt or BNRF1 trans-complemented viruses. We conclude from these findings that BNRF1 plays an important role in viral transport from the endosomes to the nucleus.

Resting B cells as a transfer vehicle for Epstein-Barr virus infection of epithelial cells

Epstein-Barr virus (EBV), an orally transmitted herpesvirus, efficiently targets B lymphocytes through binding of the viral envelope glycoprotein gp350 to the complement receptor CD21. How the virus accesses epithelial cells is less well understood, because such cells are largely resistant to infection with cell-free virus in vitro. Here, we show that, after binding to primary B cells, most Epstein-Barr virions are not internalized but remain on the B cell surface and from there can transfer efficiently to CD21-negative epithelial cells, increasing epithelial infection by 10(3)- to 10(4)-fold compared with cell-free virus. Transfer infection is associated with the formation of B cell-epithelial conjugates with gp350/CD21 complexes focused at the intercellular synapse; transfer involves the gp85 and gp110 viral glycoproteins but is independent of gp42, the HLA class II ligand that is essential for B cell entry. Therefore, through efficient binding to the B cell surface, EBV has developed a means of simultaneously accessing both lymphoid and epithelial compartments; in particular, infection of pharyngeal epithelium by orally transmitted virus becomes independent of initial virus replication in the B cell system.

Defective infectious particles and rare packaged genomes produced by cells carrying terminal-repeat-negative epstein-barr virus

The Epstein-Barr virus (EBV) lytic program includes lytic viral DNA replication and the production of a viral particle into which the replicated viral DNA is packaged. The terminal repeats (TRs) located at the end of the linear viral DNA have been identified as the packaging signals. A TR-negative (TR(-)) mutant therefore provides an appropriate tool to analyze the relationships between EBV DNA packaging and virus production. Here, we show that supernatants from lytically induced 293 cells carrying TR mutant EBV genomes (293/TR(-)) contain large amounts of viral particles devoid of viral DNA which are nevertheless able to bind to EBV target cells. This shows that viral DNA packaging is not a prerequisite for virion formation and egress. Rather surprisingly, supernatants from lytically induced 293/TR(-) cells also contained rare infectious viruses carrying the viral mutant DNA. This observation indicates that the TRs are important but not absolutely essential for virus encapsidation.

Biology and pathology of non-amidated gastrins

The regulation and extent of progastrin processing has assumed greater importance with the realisation that progastrin and its processing intermediates have functions quite separate from the biosynthetic end product gastrin-amide. The pattern of processing products generated are organ and disease specific with amidated forms predominating in the stomach and non-amidated forms being more important in colorectal carcinoma. In the stomach, non amidated gastrins sustains the acid stimulatory effect of gastrin amide on gastric acidity. The proliferation of colorectal carcinomas and cell lines are stimulated by nonamidated gastrins presumably by an autocrine regulatory loop acting through distinct receptors. The potential role of non-amidated gastrins as therapeutic targets will remain uncertain until the nature of the receptors are determined and specific antagonists developed.

Individual and self in the late Renaissance

This article argues that many traditional historical narratives of individualism have been reproduced in more recent discussions of the self and selfhood, and that attempts to discover a point at which the ‘modern’ self came into existence have been hampered by such assumptions. To provide an alternative to these approaches, discussions of the self in the late sixteenth and early seventeenth centuries will be examined. Eschewing overarching narratives, the discussion will focus on how neo-stoic sources were employed in the context of challenges to traditional forms of the humanist ethics of office-holding. Such ideas, important in writers like Montaigne, Pierre Charron, and William Cornwallis, have been associated with an idea of ‘new humanism’, but this article aims to discuss with precision how they relate to early modern ethical discussion. Here an insight can be gained into a particular philosophical development of the idea of the self. This can be more productive than some recent ‘new historicist’, or sociological, approaches to the literature of this period, which tend to the deconstruction of a particular set of sources through the use of the self as a theoretical heuristic.

Variation in utilization of computed tomography scanning for the investigation of minor head trauma in children: a Canadian experience

OBJECTIVES

To compare the utilization rates of CT scans in investigating minor head trauma in children in Canada, to identify the injuries determined by these scans, and to identify clinical findings that are highly associated with its diagnosis and the injury itself.

METHODS

A retrospective cohort study involving nine pediatric hospitals in Canada was conducted. A structured data collection method was used. Inclusion criteria included age 16 years or less, history of blunt head trauma, and a Glasgow Coma Scale score (GCS) greater than or equal to 13. Data collected included demographic information, type of injury, relevant clinical information, computed tomography (CT) scan data, and clinical outcome. Clinical findings associated with CT scan and positive CT scan were identified using logistic regression.

RESULTS

One thousand one hundred sixty-four children were included in the study. One hundred seventy-one (15%) had a CT scan, of which 60 (35%) were abnormal. There was a significant difference in the rate of ordering of CT scans among the participating hospitals, but no significant difference in the rate of abnormal CT scans. Mechanism of injury, GCS, and loss of consciousness were significantly related to the presence of an abnormal CT scan.

CONCLUSIONS

Although there is a significant difference in the utilization of CT scans to investigate minor head trauma in children across Canada, there is no significant difference in the frequency of head injuries in these patients. This suggests that it may be possible to determine clinical criteria that are predictive of a head injury in these patients.

Personal and clinical skin cancer prevention practices of US women physicians

OBJECTIVE

To document physician clinical and personal skin cancer prevention practices and associated characteristics.

DESIGN

A cross-sectional questionnaire survey of a representative sample of US women physicians.

SETTING

Mail survey.

SUBJECTS

Three thousand thirty-two nondermatologists and 95 dermatologists.

MAIN OUTCOME MEASURE

Personal and clinical practices.

RESULTS

Twenty-seven percent of nondermatologists counseled or screened their typical patients on skin cancer or sunscreen use at least once a year, while 49% did so less frequently, and 24% never counseled or screened at all. Of the 95 dermatologists, two thirds reported counseling or screening their typical patients at every visit. In bivariate analysis of nondermatologists, the distribution of counseling or screening was significantly (P<.05) associated with the following personal and professional characteristics: frequent sunscreen use, recent (within 2 years) skin examination, good health status, a primary care specialty, self-confidence in counseling or screening, extensive training in counseling or screening, high perceived relevance to the practice of the counseling or screening, nonurban practice site, and nonhospital-based or non-medical school-based practice. We found that 48% of all physicians always or nearly always used sunscreen, and 25% had received a clinical skin examination in the previous 2 years.

CONCLUSIONS

Although many primary care physicians report ever counseling or screening their typical patients about skin cancer and sunscreen use, increased professional education for primary care physicians could improve patient counseling about skin cancer prevention.

Continuing medical education habits of US women physicians

OBJECTIVES

To quantify the time women physicians spend on continuing medical education (CME) in total and by type of activity and to assess the impact of various demographic and professional characteristics on CME practices.

METHODS

We analyzed CME habits among 4501 female physicians (a 59% response rate) using a 1994 national questionnaire-based survey, the Women Physicians' Health Study.

RESULTS

US women physicians reported spending a monthly mean of 12.5 hours on CME, including 5.1 hours reading medical journals, 3.1 reading medical textbooks, 3.7 attending live CME lectures, 0.7 listening to CME audio tapes, and 0.4 watching medical television or videos. They also spent 0.9 hours per month learning from lay health media. Physicians with subspecialty training, medical school employment, and a non-US birthplace reported significantly (p < 0.05) more CME hours; age, ethnicity, region, specialty type, practice locale, career satisfaction, and board certification did not significantly predict reported CME hours.

CONCLUSIONS

US women physicians reported spending an average of one-half hour each work day on CME, including about one hour per week reading medical journals, their most commonly reported CME activity.

Intranets are the key to new database strategies

Health care organizations are finding that easy-to-use intranets can improve access to data. Because intranets are easier to navigate than other networks--and often less expensive--many provider and payer organizations are reorienting their database plans. But some organizations move too fast with new plans and have difficulty standardizing enterprisewide data, threatening intranet viability.

Puncture wounds

Puncture wounds are common in children, and most are uncomplicated. For children who have a delayed presentation or signs of infection, consider the possibility of a retained foreign body. The diagnosis of P aeruginosa osteochondritis should be considered in any child who exhibits persistent signs and symptoms after puncture wounds; timely use of laboratory tests, radiologic imaging, and orthopedic referral is required.

Ex vivo expansion and differentiation of unselected peripheral blood progenitor cells in serum-free media

The ability to expand and differentiate unselected PBPC was investigated. Cells were grown in serum-free media containing stem cell factor, GCSF and megakaryocyte growth and development factor (pegylated PEG-rHuMGDF) with or without supplemental serum. Optimal proliferation occurred when PBPC were cultured without prior Ficoll-Paque separation in serum-free media. Cell yields after 17 days of culture were proportional to the percentage of CD34+ cells in the starting population and were 1170+/-302-fold higher than the starting numbers of CD34+ cells. Granulocyte-macrophage colony-forming units increased over 12 days of culture, whereas the numbers of erythroid colony-forming cells peaked between 4 and 7 days. Elimination of PEG-rHuMGDF from cell cultures resulted in significantly lower yields of myeloid and erythroid colony-forming cells and total cell numbers. Cell differentiation into neutrophils was indicated by progressive increases in CD11b, CD15, and CD66b expression. Expanded neutrophils phagocytosed and killed bacteria as efficiently as neutrophils from normal donors. Large-scale expansion studies yielded similar proliferation and differentiation results as parallel small-scale cultures. Therefore, unselected PBPC can be efficiently expanded and differentiated into large numbers of functional mature neutrophils.

U.S. women physicians' residential radon testing practices

INTRODUCTION

These analyses were designed to elucidate U.S. physicians' perception of residential radon risk, as measured by the prevalence of residential radon testing using a representative sample of U.S. women physicians from the Women Physicians' Health Study database. In addition, characteristics of women physicians who were more likely to have conducted a residential radon test were identified.

METHODS

A random sample (n = 4,501 respondents) of U.S. women physicians aged 30 to 70 was obtained in the Women Physicians' Health Study. Analyses were conducted using SUDAAN.

RESULTS

The overall prevalence of residential radon testing among respondents was 18%, 2- to 6-fold higher than any estimate of residential radon testing in the general population. The strongest relationship with radon testing observed through logistic regression was with marital status; age, ethnicity, and region of residence were also related.

CONCLUSION

The study demonstrates that although U.S. women physicians are more likely to have conducted a personal residential radon test than the general population, 82% report not having done so. Increasing the awareness of physicians about the health risks associated with prolonged radon exposure will be essential if they are to play a role in addressing this important public health problem.

Lexically-based learning and early grammatical development

Pine & Lieven (1993) suggest that a lexically-based positional analysis can account for the structure of a considerable proportion of children's early multiword corpora. The present study tests this claim on a second, larger sample of eleven children aged between 1;0 and 3;0 from a different social background, and extends the analysis to later in development. Results indicate that the positional analysis can account for a mean of 60% of all the children's multiword utterances and that the great majority of all other utterances are defined as frozen by the analysis. Alternative explanations of the data based on hypothesizing underlying syntactic or semantic relations are investigated through analyses of pronoun case marking and of verbs with prototypical agent-patient roles. Neither supports the view that the children's utterances are being produced on the basis of general underlying rules and categories. The implications of widespread distributional learning in early language development are discussed.

Murine IL-10 fails to reduce GVHD despite inhibition of alloreactivity in vitro

Graft-versus-host disease (GVHD) is a serious complication following allogeneic bone marrow transplantation (BMT). Initial immunologic events that are thought to lead to clinical GVHD include allogeneic antigen presentation, CD4+ T cell proliferation and eventually generation of specific cytotoxic lymphocytes. Interleukin-10 (IL-10) has been shown to inhibit the function of antigen presenting cells (APC) and to reduce lymphocyte proliferation. In this study we investigated the possible role of recombinant murine IL-10 (rmIL-10) as prophylactic treatment of GVHD in a murine BMT model involving B10.BR donor mice (H-2k) and AKR recipients (H-2k). In particular, we wished to determine whether early post-BMT administration of IL-10 would suppress GVHD by interfering with macrophage function and inflammatory cytokine production during the proposed "afferent' phase of GVHD. In MLR assays, rmIL-10 significantly inhibited the proliferation of donor spleen cells when stimulated by irradiated recipient spleen cells in a dose-dependent manner. In murine BMT, rmIL-10 was administered exogenously by intraperitoneal injection of 100 U daily in two different dosage schedules, on days-1, 0, 1, 2, 3, 6 to target the early post-BMT phase, and days-1, 0, 3, 5, 7, 10 after BMT, to administer the same total dose throughout the engraftment period. IL-10 injected mice had lower plasma IL-1 alpha levels on day 3 (12 pg/ml vs 64 pg/ml in controls, P < 0.05), suggesting that both macrophage function and inflammatory cytokine production were inhibited. In contrast to the MLR data, no significant improvement in morbidity and mortality from GVHD was observed. Therefore, IL-10 does not appear to be useful in GVHD prophylaxis.

Regulation of HIV-1 infection in astrocytes: expression of Nef, TNF-alpha and IL-6 is enhanced in coculture of astrocytes with macrophages

'Restricted' human immunodeficiency virus type (HIV-1) infection of astrocytes is recognized in vivo in some pediatric and adult AIDS brains and in vitro in a small proportion of transfected primary fetal astrocytes. We investigated the extent of HIV-1JR-FL expression in fetal astrocytes and macrophages cultivated alone or together. Peak HIV-1 p24 antigen titres in supernatant fluids of macrophage cultures were increased with monocyte/macrophages from certain donors and were higher when macrophages were cocultivated with astrocytes. Structural HIV-1 gene (gp 41 and pol) products (protein and mRNA) were observed only in macrophages. Ten days after HIV-1JR-FL infection, astrocytes in a monoculture were stained negative or only weakly positive (1-2+) for Nef, whereas in a coculture up to 100% of astrocytes displayed Nef staining (up to 4+) in the cytoplasm. The streptavidine-biotine-peroxidase technique with certain monoclonal antibodies to Nef (Ovod et al, 1992) was specific for infected astrocytes. The intensity of Nef staining was higher in astrocytes cultivated with monocyte/macrophages from certain donors. In the coculture, tumor necrosis factor-alpha (TNF-alpha) was expressed in the astrocyte cytoplasm earlier after coinfection with HIV-1 and cytomegalovirus (CMV) compared to infection with HIV-1 alone. Interleukin-6 (IL-6) was secreted spontaneously and transiently in uninfected cocultures, but in a prolonged fashion following HIV-1 and HIV-1/CMV infections. The interactions between HIV-1- and CMV-infected macrophages and astrocytes lead to upregulation of TNF-alpha and IL-6 and enhancement of productive HIV-1 infection of macrophages and of 'restricted' HIV-1 infection of astrocytes with implications for the pathogenesis of AIDS dementia.

Calcium binds dynamin I and inhibits its GTPase activity

Synaptic vesicle recycling is a neuronal specialization of endocytosis that requires the GTPase activity of dynamin I and is triggered by membrane depolarization and Ca2+ entry. To establish the relationship between dynamin I GTPase activity and Ca2+, we used purified dynamin I and analyzed its interaction with Ca2+ in vitro. We report that Ca2+ bound to dynamin I and this was abolished by deletion of dynamin's C-terminal tail. Phosphorylation of dynamin I by protein kinase C promoted formation of a dynamin I tetramer and increased Ca2+ binding to the protein. Moreover, Ca2+ inhibited dynamin I GTPase activity after stimulation by phosphorylation or by phospholipids but not after stimulation with a GST-SH3 fusion protein containing the SH3 domain of phosphoinositide 3-kinase. These results suggest that in resting nerve terminals, phosphorylation of dynamin I by protein kinase C converts it to a tetramer that functions as a Ca(2+)-sensing protein. By binding to Ca2+, dynamin I GTPase activity is specifically decreased, possibly to regulate synaptic vesicle recycling.

Sexual abuse and body-image distortion in the eating disorders

It has been suggested that there is a link between sexual abuse and bodily self-deprecation in women with eating disorders. In order to test that model, this study considers whether reported sexual abuse is associated with body-image distortion in anorexia and bulimia nervosa. There was no association with the reported presence of a history of abuse. However, the nature of any abuse was important. In particular, women who reported more recent abuse had a substantially greater level of bodysize overestimation. The clinical implications of this finding are discussed.

Effect of a human immunoglobulin preparation for intravenous use in a rabbit model of meningococcal endotoxin-induced shock

BACKGROUND AND METHODS

Endotoxin shock is mediated by various cytokines, including tumor necrosis factor. Treatment of patients with i.v. immunoglobulin has been shown to reduce the concentration of circulating cytokines. The purpose of this study was to determine the protective effects of immunoglobulin for i.v. use on meningococcal endotoxin-induced shock in a rabbit model. Experimental animals were challenged with i.v. meningococcal endotoxin (lipo-oligosaccharide) 10 micrograms/kg, and treated with either a 2-hr i.v. immunoglobulin infusion (400 mg/kg) or a similar saline infusion that was initiated 30 mins before endotoxin challenge. Control animals were challenged with saline alone.

RESULTS

Compared with untreated control animals, pulse rate increased (p less than .007) and mean arterial pressure and serum bicarbonate concentrations decreased (p less than .02) in both experimental groups, but did not differ between immunoglobulin-treated and saline-treated animals (p greater than .05) at any time after the endotoxin challenge. Geometric mean serum endotoxin concentrations were significantly (p less than .03) lower in the immunoglobulin-treated animals at 60, 120, 180, 240, 300, and 360 mins after the endotoxin challenge. The geometric mean serum tumor necrosis factor level at 1 hr after the endotoxin challenge in the immunoglobulin-treated experimental animals was lower than in saline-treated animals (5.53 vs. 8.47 tumor necrosis factor enzyme-linked immunosorbent assay U/mL), but not significantly so (p greater than .05). Mortality rate was similar in both experimental groups; eight (67%) of 12 saline-treated experimental rabbits and seven (70%) of ten immunoglobulin-treated rabbits died. All untreated control animals survived 24 hrs.

CONCLUSIONS

In this model of circulatory shock in rabbits, i.v. immunoglobulin: a) does not significantly alter the physiologic responses to endotoxin challenge; b) significantly reduces endotoxin concentrations; c) reduces tumor necrosis factor concentrations, but not significantly; and d) does not improve survival rate.

Limulus antilipopolysaccharide factor protects rabbits from meningococcal endotoxin shock

Limulus antilipopolysaccharide factor (LALF), an 11.8-kDa peptide isolated from amebocytes of Limulus polyphemus, neutralizes meningococcal lipooligosaccharide (LOS)-induced gelation of limulus amebocyte lysate. Rabbits challenged with an LD90 of LOS (10 micrograms/kg) premixed with LALF in vitro (n = 10) had significantly higher mean arterial pressure, arterial pH, serum bicarbonate concentrations, and survival (90% vs. 8%, P = .005) than did rabbits challenged with LOS alone. Relative to untreated controls, rabbits pretreated with LALF intravenously (iv) at 1.2 mg/kg (n = 21) also had significant improvements in physiologic measurements and higher survival (52% vs. 8%, P = .003). Even when LALF (1.2 mg/kg iv) was given 1/2 h after LOS challenge, animals showed significant improvements in physiologic measurements and survival (33% vs. 8% in untreated controls P = .028). LALF-treated animals also had significantly lower circulating endotoxin activity and tumor necrosis factor concentrations. Thus, LALF attenuates the toxic effects of meningococcal LOS in rabbits even when administered after LOS challenge and deserves further evaluation as a potential therapeutic agent for treating gram-negative septic shock.

Effect of meningococcal endotoxin in a rabbit model of shock

Endotoxin in the form of a lipooligosaccharide (LOS) plays a key role in the development of shock in meningococcal sepsis. To examine hemodynamic and biochemical alterations during meningococcal endotoxic shock, we established a rabbit model. Thirty-nine rabbits, weighing 2.5-4.4 kg, were studied. After anesthesia with intramuscular ketamine (20 mg/kg) and xylazine (4 mg/kg), femoral venous and arterial catheters were inserted. Control animals received only saline, while rabbits in each of four additional groups were given LOS in 10-fold increments from 0.1 microgram/kg to 100 microgram/kg. Mean arterial pressure (MAP), heart rate (HR), respirations (RR), temperature (T), urine output, and arterial blood gases (pH, PCO2, PO2, and bicarbonate) were determined at baseline and hourly. Endotoxin levels and TNF levels were measured at 30, 60, 120, 180, 240, 300, and 360 min post-LOS. Survival was recorded. One-way analysis of variance (ANOVA) and the Scheffe procedure, paired samples t-test, two-tailed t-test, and Fisher's exact test were used. Pearson's coefficients were calculated. Animals receiving meningococcal LOS developed tachycardia and compensated metabolic acidosis with an initially normal pH and MAP. With progression of the shock state, the pH decreased and hypotension ensued. Maximal levels of endotoxin were measured 30 min after LOS injection and declined during the ensuing 6 hr. TNF rose from undetectable to markedly elevated levels and peaked at 60-120 min post-LOS. Increasing the amount of injected endotoxin produced more profound degrees of shock until a dose of 10.0 micrograms/kg was reached. There was no correlation between serum TNF at 60 min and survival at 6 hr or 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of polymyxin B on experimental shock from meningococcal and Escherichia coli endotoxins

Meningococcemia is the most frequent cause of septic shock in healthy children. To determine whether polymyxin B (PMB) might improve mortality from meningococcal shock, its protective activity was evaluated in rabbits challenged with an LD90 of meningococcal lipooligosaccharide (LOS) and compared with an LD80 of Escherichia coli O111:B4 lipopolysaccharide (LPS). PMB (5 mg/kg) administered intravenously 30 min before meningococcal LOS challenge had no significant effect on heart rate, mean arterial pressure, serum bicarbonate, serum tumor necrosis factor (TNF) levels, or survival relative to controls. However, PMB premixed with LOS in vitro increased serum bicarbonate levels (P less than .05) and improved 24-h survival (P less than .05). In contrast, PMB given before E. coli LPS challenge increased serum bicarbonate levels, decreased TNF levels, and improved 24-h survival (all, P less than .05). In vitro studies confirmed that PMB at 10 micrograms/ml neutralized E. coli LPS but not meningococcal LOS activity. Thus, pretreatment with PMB apparently protects rabbits against shock induced by E. coli LPS but not by meningococcal LOS.

Combined therapy with recombinant granulocyte colony-stimulating factor and erythropoietin decreases hematologic toxicity from zidovudine

Twenty-two patients with acquired immunodeficiency syndrome (AIDS) or severe AIDS-related complex and multilineage hematopoietic defects were treated with recombinant granulocyte colony-stimulating factor (G-CSF) and erythropoietin (EPO) in a phase I/II trial. All patients were neutropenic and anemic after withdrawal of all bone marrow-suppressive drugs. Daily, G-CSF was subcutaneously self-administered until an absolute neutrophil count (ANC) greater than 6,000/microL was achieved and maintained for 2 weeks. Subcutaneous EPO was added to the regimen and the dose increased until an increase of 15 g/L of hemoglobin was observed. Groups of patients were administered increasing doses of zidovudine to determine their tolerance. G-CSF and EPO therapy was continued with dose modification to maintain an ANC greater than 1,500/microL and hemoglobin greater than 100 g/L. The dose of zidovudine was not altered. All 22 patients responded to G-CSF with a mean 10-fold increase in neutrophils occurring in less than 2 weeks. Significant increases in CD4 and CD8 cell number, lymphocyte proliferative response, and bone marrow cellularity were seen. EPO therapy increased hemoglobin in all 20 evaluable patients within 8 weeks. Sixteen patients received 1,000 mg and four patients received 1,500 mg of zidovudine per day. The reinstitution of zidovudine resulted in a decline in reticulocytes and hemoglobin and the reappearance of transfusion requirements in eight of the 20 patients, six of whom had the study medications stopped. No patient had the study medications stopped because of neutropenia or thrombocytopenia. Toxicities were mild and did not require dose modifications. Limiting dilution plasma and lymphocyte co-cultures for HIV as well as serum p24 antigen levels did not change significantly during G-CSF or combined G-CSF and EPO therapy. HIV p24 antigen decreased significantly with zidovudine therapy. Opportunistic infections occurred in 14 patients but were successfully treated with myelosuppressive antimicrobial agents, including ganciclovir, without the development of neutropenia. These results suggest that combined therapy with G-CSF and EPO may improve the neutropenia and anemia of AIDS. Combined therapy may allow the resumption of full-dose zidovudine in most patients intolerant of the hematologic effects of zidovudine without apparent alteration of HIV expression or the efficacy of zidovudine.