Analyzing immune response to engineered hydrogels by hierarchical clustering of inflammatory cell subsets

Understanding the immune response to hydrogel implantation is critical for the design of immunomodulatory biomaterials. To study the progression of inflammation around poly(ethylene glycol) hydrogels presenting Arg-Gly-Asp (RGD) peptides and vascular endothelial growth factor, we used temporal analysis of high-dimensional flow cytometry data paired with intravital imaging, immunohistochemistry, and multiplexed proteomic profiling. RGD-presenting hydrogels created a reparative microenvironment promoting CD206+ cellular infiltration and revascularization in wounded dorsal skin tissue. Unbiased clustering algorithms (SPADE) revealed significant phenotypic transition shifts as a function of the cell-adhesion hydrogel properties. SPADE identified an intermediate macrophage subset functionally regulating in vivo cytokine secretion that was preferentially recruited for RGD-presenting hydrogels, whereas dendritic cell subsets were preferentially recruited to RDG-presenting hydrogels. Last, RGD-presenting hydrogels controlled macrophage functional cytokine secretion to direct polarization and vascularization. Our studies show that unbiased clustering of single-cell data provides unbiased insights into the underlying immune response to engineered materials.

Dual delivery of IL-10 and AT-RvD1 from PEG hydrogels polarize immune cells towards pro-regenerative phenotypes

Inflammation after traumatic injury or surgical intervention is both a protective tissue response leading to regeneration and a potential cause of wound complications. One potentially successful strategy to harness to pro-regenerative roles of host inflammation is the localized delivery of bioactive materials to induce immune suppressive cellular responses by cells responding to injury. In this study, we designed a fully synthetic poly (ethylene) glycol (PEG)-based hydrogel to release the specialized pro-resolving lipid mediator aspirin-triggered resolvin-D1 (AT-RvD1) and recombinant human interleukin 10 (IL-10). We utilized a unique side-by-side internally controlled implant design wherein bioactive hydrogels were implanted adjacent to control hydrogels devoid of immune modulatory factors in the dorsal skinfold window chamber. We also explored single-immune cell data with unsupervised approaches such as SPADE. First, we show that RGD-presenting hydrogel delivery results in enhanced immune cell recruitment to the site of injury. We then use intra-vital imaging to assess cellular recruitment and microvascular remodeling to show an increase in the caliber and density of local microvessels. Finally, we show that the recruitment and re-education of mononuclear phagocytes by combined delivery IL-10 and AT-RvD1 localizes immune suppressive subsets to the hydrogel, including CD206⁺ macrophages (M2a/c) and IL-10 expressing dendritic cells in the context of chronic inflammation following surgical tissue disruption. These data demonstrate the potential of combined delivery on the recruitment of regenerative cell subsets involved in wound healing complications.

Combination bupropion SR and varenicline for smoking cessation: a systematic review

BACKGROUND

Tobacco is the leading cause of preventable death in the world. Current cessation medications include nicotine replacement therapy (NRT), varenicline, and bupropion, while combination therapy primarily entails NRT with either varenicline or bupropion. However, recent studies have examined varenicline and bupropion in combination.

OBJECTIVES

A systematic review assessing the efficacy and safety of combination varenicline and bupropion was conducted.

METHODS

PubMed and Clinicaltrials.gov were searched using terms: "varenicline combination", "bupropion combination", "bupropion AND varenicline", and "bupropion AND varenicline combination smoking cessation", yielding four studies including 1193 total patients.

RESULTS

Combination therapy yielded greater efficacy than varenicline monotherapy in two randomized controlled trials and one retrospective outcomes study. One single-arm Phase II trial provided additional efficacy and safety data. Of the prospective trials, one displayed a greater 4-week smoking abstinence for weeks 8-11 with combination (39.8%) versus monotherapy (25.9%) (OR = 1.89; 95% CI = 1.07-3.35). The other demonstrated greater prolonged abstinence (continuous abstinence from week 2) at 12 weeks (OR = 1.49; 95% CI = 1.05-2.12) and 26 weeks (OR = 1.52; 95% CI = 1.04-2.22), though results were not significant at 52 weeks in this study. The retrospective study displayed higher success rates (continuous abstinence rates at 52 weeks) with combination varenicline and bupropion (55.0%; compared to varenicline monotherapy (32.1%), p < 0.001). Subgroup analyses suggest that this combination may be more beneficial in males and patients with higher baseline nicotine dependence.

CONCLUSION

To the authors' knowledge, this is the first review conducted to compile current literature on this novel pharmacotherapy combination for smoking cessation. Combination bupropion SR and varenicline displayed greater efficacy in smoking cessation than varenicline monotherapy, though further safety analysis is warranted to rule out additive psychiatric adverse effects.

Akt inhibition upregulates FasL, downregulates c-FLIPs and induces caspase-8-dependent cell death in Jurkat T lymphocytes

In T lymphocytes, the role of Akt in regulating Fas/Fas ligand (FasL)-mediated apoptotic signaling and death is not clearly understood. In this study, we observed that inhibition of Akt causes enhanced expression of FasL mRNA and protein and increased death-inducing signaling complex (DISC) formation with Fas-associated death domain (FADD) and procaspase-8 recruitment. Also, caspase-8 was activated at the DISC with accompanying decrease in c-FLIPs expression. FasL neutralizing antibody significantly decreased apoptotic death in the Akt-inhibited T cells. Additionally, Akt inhibition-induced Fas signaling was observed to link to the mitochondrial pathway via Bid cleavage. Further, inhibition of caspase-8 activity effectively blocked the loss of mitochondrial membrane potential and DNA fragmentation, suggesting that DISC formation and subsequent caspase-8 activation are critical initiating events in Akt inhibition-induced apoptotic death in T lymphocytes. These data demonstrate yet another important survival function governed by Akt kinase in T lymphocytes, which involves the regulation of FasL expression and consequent apoptotic signaling.

Hex-1, a gene unique to filamentous fungi, encodes the major protein of the Woronin body and functions as a plug for septal pores

We have identified a gene, named hex-1, that encodes the major protein in the hexagonal crystals, or Woronin bodies, of Neurospora crassa. Analysis of a strain with a null mutation in the hex-1 gene showed that the septal pores in this organism were not plugged when hyphae were damaged, leading to extensive loss of cytoplasm. When grown on agar plates containing sorbose, the hex-1(-) strain showed extensive lysis of hyphal tips. The HEX-1 protein was predicted to be 19,125 Da. Analysis of the N-terminus of the purified protein indicated that 16 residues are cleaved, yielding a protein of 17,377 Da. A polyclonal antibody raised to the HEX-1 protein recognized multiple forms of the protein, apparently dimers and tetramers that were resistant to solubilization by sodium dodecyl sulfate and reducing reagents. Treatment of the protein with phosphatase caused dissociation of these oligomers. Preparations enriched in Woronin bodies contained catalase activity, which was not detected in comparable fractions from the hex-1(-) mutant strain. These results support the hypothesis that the Woronin body is a specialized peroxisome that functions as a plug for septal pores.

Myotonic dystrophy in transgenic mice expressing an expanded CUG repeat

Myotonic dystrophy (DM), the most common form of muscular dystrophy in adult humans, results from expansion of a CTG repeat in the 3' untranslated region of the DMPK gene. The mutant DMPK messenger RNA (mRNA) contains an expanded CUG repeat and is retained in the nucleus. We have expressed an untranslated CUG repeat in an unrelated mRNA in transgenic mice. Mice that expressed expanded CUG repeats developed myotonia and myopathy, whereas mice expressing a nonexpanded repeat did not. Thus, transcripts with expanded CUG repeats are sufficient to generate a DM phenotype. This result supports a role for RNA gain of function in disease pathogenesis.

Pilot study of growth hormone administration during the refeeding of malnourished anorexia nervosa patients

OBJECTIVE

In anorexia nervosa (AN), medical stabilization and nutritional repletion are pivotal steps toward physical and psychological recovery. Nutritional stabilization is often difficult in this patient group. Recombinant human growth hormone (rhGH) has been safely used as adjuvant therapy in other groups of malnourished patients. We hypothesize that rhGH treatment will hasten medical stabilization in AN patients.

STUDY DESIGN

Fifteen patients admitted for inpatient treatment for AN, ages 12-18 years, were enrolled in a 28-day randomized, double-blind, placebo-controlled study. Patients received rhGH (0.05 mg/kg subcutaneously) or an equivalent volume of placebo daily. Outcome measures included time to reach medical/cardiovascular stability, rate of weight gain, and duration of hospitalization. All patients received a standard refeeding protocol.

RESULTS

Mean admission body mass index was 14.5 kg/m2. The rhGH and placebo groups did not differ significantly in admission weight, BMI or daily caloric intake. Patients treated with rhGH reached medical/cardiovascular stability more rapidly than those treated with placebo (median 17 vs. 37 days, p = 0.02). Numerical but not statistically significant improvements were seen in weight gain and length of hospitalization in the rhGH group.

CONCLUSION

Patients treated with rhGH achieved medical/cardiovascular stability more rapidly than those treated with placebo, and this, in turn, decreased the length of stay.

Review article: potential gastrointestinal effects of long-term acid suppression with proton pump inhibitors

This review examines the evidence for the development of adverse effects due to prolonged gastric acid suppression with proton pump inhibitors. Potential areas of concern regarding long-term proton pump inhibitor use have included: carcinoid formation; development of gastric adenocarcinoma (especially in patients with Helicobacter pylori infection); bacterial overgrowth; enteric infections; and malabsorption of fat, minerals, and vitamins. Prolonged proton pump inhibitor use may lead to enterochromaffin-like cell hyperplasia, but has not been demonstrated to increase the risk of carcinoid formation. Long-term proton pump inhibitor treatment has not been documented to hasten the development or the progression of atrophic gastritis to intestinal metaplasia and gastric cancer, although long-term studies are required to allow definitive conclusions. At present, we do not recommend that patients be tested routinely for H. pylori infection when using proton pump inhibitors for prolonged periods. Gastric bacterial overgrowth does increase with acid suppression, but important clinical sequelae, such a higher rate of gastric adenocarcinoma, have not been seen. The risk of enteric infection may increase with acid suppression, although this does not seem to be a common clinical problem with prolonged proton pump inhibitor use. The absorption of fats and minerals does not appear to be significantly impaired with chronic acid suppression. However, vitamin B12 concentration may be decreased when gastric acid is markedly suppressed for prolonged periods (e.g. Zolllinger-Ellison syndrome), and vitamin B12 levels should probably be assessed in patients taking high-dose proton pump inhibitors for many years. Thus, current evidence suggests that prolonged gastric acid suppression with proton pump inhibitors rarely, if ever, produces adverse events. Nevertheless, continued follow-up of patients taking proton pump inhibitors for extended periods will provide greater experience regarding the potential gastrointestinal adverse effects of long-term acid suppression.

Increased monocyte nuclear factor-kappaB activation and tumor necrosis factor production in alcoholic hepatitis

Increased tumor necrosis factor-a activity has been reported in patients with alcoholic hepatitis and is implicated in its pathogenesis. The aim of this study was to investigate potential mechanisms of increased tumor necrosis factor-a activity in alcoholic hepatitis. Monocyte nuclear factor-kB activity was assessed by electrophoretic mobility shift assay, monocyte tumor necrosis factor-a mRNA was semi-quantitatively assessed by reverse transcriptase polymerase chain reaction, and tumor necrosis factor-a in monocyte culture supernatants was measured. There was significantly greater spontaneous nuclear factor-kB activity in the monocytes of 6 patients with alcoholic hepatitis as compared with that in the monocytes of control subjects. There was spontaneous tumor necrosis factor-a mRNA and tumor necrosis factor-a release from the monocytes of patients with alcoholic hepatitis but not from the monocytes of normal subjects. Endotoxin increased nuclear factor-kB activity and induced tumor necrosis factor-a mRNA and tumor necrosis factor-a release from normal subjects' monocytes. Endotoxin further increased nuclear factor-kB activity, tumor necrosis factor-a mRNA, and tumor necrosis factor-a release from the monocytes of patients with alcoholic hepatitis. Supershift assays indicate that the monocyte nuclear factor-kB activation involves the p50 and p65 subunits. Dysregulated tumor necrosis factor-a metabolism in alcoholic hepatitis monocytes is associated with increased nuclear factor-kB activity and tumor necrosis factor-a mRNA expression.

Complementary and alternative medicine and gastrointestinal diseases

Complementary and alternative medicine (CAM) is becoming increasingly utilized as a form of health care, with recent studies suggesting that over 40% of Americans use some form of CAM. This has major financial implications for the health care industry. Traditional physicians frequently are unaware of CAM use by their patients, and there are potential interactions between CAM and traditional forms of medical therapy. Many of the medicinal CAM agents have been used for their postulated anti-inflammatory and/or antifibrotic effects. CAM is especially frequently used in patients with chronic diseases. This review discusses CAM use in three types of chronic gastrointestinal diseases--liver disease, irritable bowel syndrome and dyspepsia, and inflammatory bowel disease.

Concurrent validity of the Bayley Scales of Infant Development II Motor Scale and the Peabody Developmental Motor Scales in two-year-old children

Concurrent validity of the Bayley Scales of Infant Development, Second Edition (BSID II) Motor Scale and the Peabody Developmental Motor Scales (PDMS) was examined by administering both tests to 38 two-year-old Native American children. A correlation analysis of age equivalent scores indicated very good to high correlation for the BSID II Motor Scale with the PDMS Fine Motor Scale (PDFMS) (r = .87) and the PDMS Gross Motor Scale (PDGMS) (r = .83). A correlation analysis of standard scores showed poor to unacceptable correlation between the BSID II Motor Scale with the PDFMS (r = .64) and the PDGMS (r = .49); further, there was poor agreement between the classifications of significantly delayed, mildly delayed, and within normal limits performance on each test. The PDFMS tended to classify children lower than the BSID II Motor Scale. The scores of the relatively younger children within each of the PDMS 6-month age categories agreed less between the tests than did the scores of the relatively older children. In conclusion, this study provides evidence for the concurrent validity of the BSID II Motor Scale and the PDMS for age equivalent scores, but not for standard scores of 2-year-old children. Professionals must be aware of the strengths and limitations of the BSID II and the PDMS, and choose appropriately to avoid denial of or over-referral for services for young children.

Motor development of Native American children on the Peabody Developmental Motor Scales

OBJECTIVE

Native American children have not been widely represented in the normative samples of standardized tests assessing motor development. This study investigated the cultural relevance of the Peabody Developmental Motor Scales (PDMS) in 2-year-old Native American children who are typically developing.

METHOD

The PDMS was administered to a sample of 44 Pueblo children who were 24 months through 35 months of age and typically developing. Each child's family also completed a parent questionnaire addressing the child's development and family demographics. Participant scores were compared with those of the normative sample.

RESULTS

The sample scored significantly lower than the normative sample (p < or = .001) on the Fine Motor Scale, and, when gender was taken into consideration, all but the older girls (30 months-35 months of age) had significantly lower scores. All but the younger girls (24 months-29 months of age) scored within the normal range on the Gross Motor Scale.

CONCLUSION

Our results with this small sample suggest that caution be used when comparing motor performance (especially fine motor abilities) of 2-year-old Native American children against the PDMS normative data.

Evaluation of the feasibility and use of a prototype remote drug delivery capsule (RDDC) for non-invasive regional drug absorption studies in the GI tract of man and beagle dog

PURPOSE

Evaluate a prototype Remote Drug Delivery Capsule (RDDC) for use in beagle dogs and human volunteers for non-invasive drug absorption studies in different regions of the gastrointestinal tract.

METHODS

The device was dual radiolabeled and GI transit of the RDDC was monitored by gamma scintigraphy. Beagles were used initially to demonstrate the functional utility of the device where a solution of ranitidine hydrochloride (150 mg) was non-invasively delivered to the stomach, proximal small intestine and distal small intestine. A subsequent first time in human study enrolled twelve healthy male volunteers where the intended site of release was the stomach, early small bowel, distal small bowel or colon.

RESULTS

Preliminary studies conducted in beagles indicated that the RDDC operated successfully and the onset of ranitidine serum levels were dependent on the time of capsule activation and site of drug release. Results from the human study showed that all twelve subjects swallowed the device with no discomfort. Mean gastric emptying of the RDDC was 1.50 +/- 1.28 h (range = 0.25 to 4.25 h), and total small intestine transit was 4.79 +/- 1.82 h (range = 2.00 to 8.25 h). The capsule was retrieved from the feces at 30.25 +/- 15.21 h (range = 14.12 to 74.25 h) and there were no reported adverse events. The prototype RDDC operated successfully in nine of the twelve human volunteers and the cause for the three failures was attributed to mechanical failure while the electronics assembly performed favorably.

CONCLUSIONS

This prototype remote control capsule was shown to be well tolerated and functional to use in human volunteers as well as beagles. The application of the device coupled with gamma scintigraphy has the potential to be a valuable and rapid method to non-invasively evaluate regional drug absorption in the gastrointestinal tract under conditions that are both pharmaceutically and physiologically meaningful.

The heart of the matter: care conferences to promote parent-professional collaboration

Children who are hospitalized frequently or who have lengthy admissions often require a large number of caregivers to meet their complex health care needs. Even the most organized of teams may experience confusion in their attempt to stay abreast of each other's care of the child. This can be particularly confusing to parents who are trying to cope with the stress of hospitalization, learning to navigate new financial and social service systems, attempting to remember the names and faces of the numerous specialists and their specific recommendations, and caring for their child. The University of New Mexico Children's Hospital in Albuquerque, New Mexico has developed and used a care conference model that includes families, medical staff, social workers, nutritionists, child life specialists, and specialized therapy provides in the process of integrating developmentally appropriate practices within the scope of necessary medical care.

Expansion of the myotonic dystrophy CTG repeat reduces expression of the flanking DMAHP gene

Myotonic dystrophy, or dystrophia myotonica (DM), is a highly variable multisystem disease in which the classic adult-onset form displays progressive muscle wasting, cataracts, heart block, gonadal atrophy, insulin resistance and neuropsychiatric impairment. Its genetic basis is an expansion of CTG trinucleotide repeats in the DMPK protein kinase gene. Among the triplet repeat expansion disorders, DM is distinguished by the extended length of the repeat tract (5-13 kb in postmortem tissue) and its location in the 3' untranslated region of the gene that contains it. The pathophysiological mechanism for multisystem degeneration in DM is not understood. In contrast to the profound muscle wasting that characterizes advanced DM, only minor histopathological abnormalities have occurred in DMPK knockout mice or in mice that overexpress a human DMPK transgene, making it unlikely that changes in DMPK activity provide a unitary explanation for the disease. A DNAse hypersensitive site that maps 0.7 kb downstream (centromeric) from the CTG repeats is eliminated on DM chromosomes. This finding indicates that the repeat expansion may alter the adjacent chromatin structure and raises the possibility that it may also affect the expression of flanking genes. An interesting candidate flanking gene is DMAHP, a recently discovered homeodomain-encoding gene. We show here that DMAHP expression in myoblasts, muscle and myocardium is reduced by the DM mutation is cis, and the magnitude of this effect depends on the extent of CTG repeat expansion. These observations support the hypothesis that DMAHP participates in the pathophysiology of DM.

The use of upper extremity anthropometrics in the clinical assessment of patients with amyotrophic lateral sclerosis

We evaluated the feasibility of using upper extremity anthropometrics to monitor the clinical status of 18 patients with amyotrophic lateral sclerosis (ALS). The bone-free arm muscle area (AMA) was computed using measurement of triceps skinfold thickness and the mid-upper arm circumference according to published formulae. The AMA correlated significantly with body mass, isokinetic muscle force generation, cross-sectional muscle area on computerized tomography scanning, and pulmonary functions including forced vital capacity and maximal voluntary ventilation. Serial determinations of AMA demonstrated a decline in 10 of 13 patients over 6 months. We pilot tested the use of AMA in a clinical trial of ciliary neurotrophic factor (CNTF) in the treatment of ALS. The AMA progressively decreased by 13%, 15%, and 30% in ALS patients treated with 0 microg CNTF/kg, 15 microg CNTF/kg, and 30/microg CNTF/kg, respectively, over a 9-month treatment period. We conclude that measurement of AMA provides a simple, inexpensive method to monitor the progression of muscle atrophy in ALS patients. The technique does not require effort on the part of the patient and as such, appears to have potential utility as an outcome measure in clinical drug trials.

Kupffer cell depletion by gadolinium chloride enhances liver regeneration after partial hepatectomy in rats

Although previous work suggests that tumor necrosis factor-alpha (TNF) promotes liver regeneration after partial hepatectomy (PH), the source of TNF is unknown. If Kupffer cells release TNF after PH, then Kupffer cell depletion by gadolinium chloride (GdCl) should inhibit liver regeneration. To test this hypothesis, cytokine expression and regenerative events were compared in GdCl-treated and control rats. Functional assays and Northern blot analysis of a Kupffer cell-specific mRNA confirmed that GdCl depleted Kupffer cells. Despite this, semiquantitative reverse transcription-polymerase chain reaction analysis of total hepatic RNA showed six- to eightfold higher levels of TNF transcripts in GdCl-treated rats. In this group, PH caused 12-to 16-fold greater induction of interleukin-6, a TNF-inducible cytokine, and two- to threefold greater induction of several cytokine-regulated genes (c-jun, C/EBP-beta, and C/EBP-delta). GdCl also amplified regeneration-associated increases in the DNA binding activity of AP-1, a growth regulatory transcription factor. Furthermore, hepatic incorporation of [3H]thymidine, expression of the S-phase antigen, proliferating cell nuclear antigen, and the hepatocyte mitotic index were each significantly greater in GdCl-treated rats. Thus, although GdCl causes Kupffer cell depletion, it does not decrease liver TNF and actually enhances liver regeneration after PH.

Zinc supplementation is associated with improved neurologic recovery rate and visceral protein levels of patients with severe closed head injury

Sixty-eight patients were entered into a randomized, prospective, double-blinded controlled trial of supplemental zinc versus standard zinc therapy to study the effects of zinc supplementation on neurologic recovery and nutritional/metabolic status after severe closed head injury. One month after injury, the mortality rates in the standard zinc group and the zinc-supplemented group were 26 and 12%, respectively. Glasgow Coma Scale (GCS) scores of the zinc-supplemented group exceeded the adjusted mean GCS score of the standard group at day 28 (p = 0.03). Mean motor GCS score levels of the zinc-supplemented group were significantly higher on days 15 and 21 than those of the control group (p = 0.005, p = 0.02). This trend continued on day 28 of the study (p = 0.09). The groups did not differ in serum zinc concentration, weight, energy expenditure, or total urinary nitrogen excretion after hospital admission. Mean 24-h urine zinc levels were significantly higher in the zinc-supplemented group at days 2 (p = 0.0001) and 10 (p = 0.01) after injury. Mean serum prealbumin concentrations were significantly higher in the zinc-supplemented group (p = 0.003) at 3 weeks after injury. A similar pattern was found for mean serum retinol binding protein level (p = 0.01). A significantly larger number of patients in the standard zinc group had craniotomies for evacuation of hematoma; thus a bias may have been present. The results of this study indicate that zinc supplementation during the immediate postinjury period is associated with improved rate of neurologic recovery and visceral protein concentrations for patients with severe closed head injury.

Zinc and endothelial function

Zinc (Zn), an essential trace element, has antioxidant functions, stabilizes membranes, and plays a role in the activity of a host of Zn metalloenzymes. Zn deficiency has been shown to increase erythrocyte fragility, decrease the Zn content of the erythrocyte membrane, and alter erythrocyte membrane fluidity. Recent studies have shown that Zn deficiency induced by various mechanisms disrupts endothelial barrier cell function in vitro, and this was corrected with Zn supplementation. Moreover, physiological amounts of Zn attenuated the barrier dysfunction produced by the inflammatory cytokine tumor necrosis factor. These data have important implications for acute vascular processes, e.g., adult respiratory distress syndrome, and chronic vascular processes, e.g., atherosclerosis. The mechanisms by which Zn may affect endothelial cell function and attenuate cytokine-induced endothelial cell dysfunction are important areas of continuing investigation.

Hyperphosphorylation of p53 induced by okadaic acid attenuates its transcriptional activation function

The tumor suppressor and transcriptional factor p53 is a phosphorylated protein. Its phosphorylation states are regulated by several protein kinases and phosphatases. In this study, the wild-type p53 was transfected and expressed in chronic myelogenous leukemia K-562 cells. Incubation of the transfected cells with okadaic acid, an inhibitor of serine phosphatases 2A and 1, induced hyperphosphorylation of p53 protein. The treatment also increased the steady state level of p53 protein in the cells. However, the hyperphosphorylated p53 protein was less active in promoting transcription mediated by two p53-binding DNA elements, the ribosomal gene cluster and the p53 consensus DNA-binding sequence. Nevertheless, the decreased transcription activation was not due to decreased binding of p53 to these elements, as analyzed by mobility shift DNA-binding assays. In addition, the treatment did not induce a conformational change in p53, as assayed by two conformation-specific anti-p53 monoclonal antibodies, PAb240 and PAb1620. These results suggest that the phosphorylation induced by okadaic acid may selectively modulate the transcription activation function of p53. Consequently, phosphorylation may represent a mechanism of p53 inactivation in tumor cells that harbor the wild-type p53.

Twelve years and more than 30,000 nurse-midwife-attended births: the Los Angeles County + University of Southern California women's hospital birth center experience

This article describes the setting, policies, practices, and outcomes of the nurse-managed in-hospital birth center at Los Angeles County + University of Southern California Women's Hospital, where women are selected upon admission for birth center care. A retrospective review of available data was made; when compared with hospital records, the primary data source was found to be 96% accurate. Results of the review indicated that from 1981 to 1992, there were 36,410 birth center admissions and 30,311 births, all attended by nurse-midwives; no intrapartum maternal or fetal deaths occurred among all admissions. The intrapartum transfer rate averaged 17%, and declined steadily from a high of 28% in 1982 to a low of 7% in 1990. More in-depth review showed an overall primary cesarean birthrate of 1.8% and an operative birthrate of 4% among the 25,890 admissions and 22,490 births from 1985 to 1992. Detailed postpartum and newborn outcomes from 1982 to 1986 showed a neonatal intensive care unit admission rate of 1.5% and a one-week newborn readmission rate of 1.3% among newborns discharged within 12 to 24 hours; 85% of all newborns returned for follow-up care. This large longitudinal experience demonstrates excellent outcomes that can be achieved when nurse-midwives, working cooperatively with a multidisciplinary health care team, provide in-hospital birth center care to a predominately low-income Hispanic population using a variety of less-traditional intrapartum management techniques. Broader implications for making alternative maternity care services available for low-income women with nurse-midwives and nurses playing a central role are discussed.

Nutritional and metabolic variables correlate with amino acid forearm flux in patients with severe head injury

OBJECTIVE

To measure the arterial-venous amino acid flux across the forearm muscle in patients with severe head injury.

DESIGN

Prospective, interventional study.

SETTING

Level I trauma hospital in the neurosurgery intensive care unit (ICU) at a university medical center.

PATIENTS

Eight nonsteroid-treated patients with severe head injury.

INTERVENTIONS

Patients were prospectively randomized to receive either standard or supplemental intravenous zinc therapy.

MEASUREMENTS AND MAIN RESULTS

Net forearm alanine, glutamine, tyrosine, phenylalanine, and branch-chain amino acid forearm flux were measured and compared with metabolic markers of energy expenditure and nitrogen excretion. There was a significant inverse relationship between the measured energy expenditure/predicted energy expenditure ratio and glutamine flux (r2 = .62; p < .05). The patients with the highest measured energy expenditure/predicted energy expenditure ratio had the greatest release of glutamine from forearm muscle. Nitrogen balance was significantly correlated with leucine flux (r2 = .53; p < .05) and with isoleucine flux (r2 = .67; p < .05). The patients with the most positive nitrogen balance had the least release of branch-chain amino acids from skeletal muscle. Tyrosine flux was highly correlated with net amino acid flux (r2 = .76; p < .01). Tyrosine flux was therefore indicative of overall muscle catabolism. Four patients had an overall negative flux of amino acids from skeletal muscle. Three patients had an overall negative flux of branch-chain amino acids.

CONCLUSIONS

This preliminary descriptive report suggests that increased skeletal muscle efflux of amino acids correlates significantly with metabolic variables of hypermetabolism and hypercatabolism in nonsteroid-treated, head-injured patients.

Long-term ethanol consumption alters the hepatic response to the regenerative effects of tumor necrosis factor-alpha

The pathogenesis of chronic alcoholic liver disease is uncertain, but it may reflect an impaired wound healing response to ethanol-induced liver injury. Cell-to-cell communication such as that mediated by the cytokine tumor necrosis factor is necessary for successful liver regeneration and complete recovery from liver injury. Hence disruption of intercellular regenerative signaling may contribute to the pathogenesis of chronic alcoholic liver disease. To test this hypothesis, the cytokine and regenerative responses triggered by partial hepatectomy were compared in ethanol-fed rats and isocalorically maintained, pair-fed controls. To further clarify the effect of ethanol on tumor necrosis factor-modulated regenerative effects, we evaluated some of the rats in each feeding group after pretreatment with antibodies to tumor necrosis factor. As expected, ethanol inhibited DNA synthesis and liver cell proliferation after partial hepatectomy. Ethanol-associated inhibition of liver regeneration occurred despite apparently similar serum concentrations of the tumor necrosis factor-inducible cytokine interleukin-6. Treatment with antibodies to tumor necrosis factor 1 hr before partial hepatectomy inhibited post-partial hepatectomy induction of interleukin-6 and liver regeneration in ethanol-fed and pair-fed rats. However, serum interleukin-6 was reduced more in ethanol-fed rats than in control rats (93% vs. 66%; p < 0.05). Antibodies to tumor necrosis factor also inhibited hepatic DNA synthesis more in ethanol-fed rats than in controls (85% vs. 50%; p < 0.05). In ethanol-fed rats, the increased effect of tumor necrosis factor antibody on post-partial hepatectomy DNA synthesis suggests heightened sensitivity of hepatocytes to tumor necrosis factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines and alcoholic liver disease

It is clear that cytokines cause metabolic disturbances that are similar to known complications of AH. TNF appears to be a proximal mediator of multiple types of experimental liver injury and TNF activity is elevated in ALD, as are the levels of certain other cytokines. On the other hand, low physiologic amounts of cytokines appear to be important for liver regeneration (and perhaps are beneficial to the organism as a whole). Goals for evaluation of anticytokine therapy in ALD will be: (1) determining the timing and type of the particular anticytokine employed (such as, immediate administration of antibody followed by an inhibitor of cytokine production), (2) appropriate monitoring of drug effects on cytokine metabolism as well as liver function and outcome, and (3) maintenance of the regenerative or positive physiologic effects of cytokines while blocking the cytolytic effects. Thus, we predict that ultimate anticytokine therapy will be directed at conserving the positive growth-enhancing effects of cytokines while attenuating their cytolytic effects.

Antibodies to tumor necrosis factor-alpha inhibit liver regeneration after partial hepatectomy

Certain cytokines that are produced in liver may act as growth factors to facilitate wound healing and, hence, may influence liver regeneration. However, this hypothesis has not been directly tested. To determine whether the cytokine response evoked by partial hepatectomy (PH) modulates the process of liver regeneration, adult male rats were injected intraperitoneally with either goat polyclonal antibodies to rat tumor necrosis factor (TNF; 15 micrograms/g body wt) or an equal amount of goat anti-rat immunoglobulin G 1 h before PH. Animals were killed at 12, 24, 48, or 72 h post-PH, 1 h after injection with [3H]thymidine. Serum TNF levels were measured with the L929 cytotoxicity assay, titers of antibody to TNF were determined by enzyme-linked immunoabsorbent assay, and interleukin-6 (IL-6) concentrations were measured by B9 cell bioassay. Liver regeneration was assessed by [3H]thymidine incorporation into hepatic DNA and by immunohistochemical evidence of proliferating cell nuclear antigen (PCNA) expression. Antibodies to TNF were detected in treated rats but not in controls. Titers were highest at 12 h and progressively fell. Although TNF was never detected in serum, treatment with anti-TNF pre-PH significantly inhibited increases in serum IL-6 concentration post-PH. Anti-TNF pretreatment also inhibited [3H]thymidine incorporation into DNA, as well as expression of PCNA by both hepatocytes and liver nonparenchymal cells. These data indicate that TNF positively modulates liver regeneration after PH.

The protective effect of FK506 pretreatment against renal ischemia/reperfusion injury in rats

The effect of pretreatment with FK506 on renal ischemia and reperfusion (I/R) injury was investigated using a rat model. Animals were assigned to one of two groups (20 rats each). Group 1 animals (controls) received 0.5 ml saline while group 2 animals received FK506 (0.3 mg/kg), administered intravenously 24 hr prior to the induction of renal ischemia. A 60-min period of ischemia of the right kidney was induced, and upon reperfusion a left nephrectomy was performed. Blood samples for estimation of BUN, creatinine, and tumor necrosis factor were collected on days 0 (preischemia), 1, 2, 3, 5, 7, and 10 (postischemia). Rats were sacrificed after day 10 and renal tissue was examined histologically. All animals survived the ischemic episode. FK506 pretreatment significantly reduced the serum levels of BUN (P less than 0.02), creatinine (P less than 0.02), and TNF (P less than 0.05) as compared with that seen in controls. Histologically, at day 10, the kidneys showed the expected sequelae of prior renal I/R with various degrees of tubular damage. However, no objective differences were evident between the two groups. Based upon these data, it can be concluded that (1) FK506 pretreatment ameliorates the functional renal injury associated with I/R, (2) renal ischemia induces the release of TNF, and (3) FK506 pretreatment results in a significant inhibition of TNF production. These data suggest that the release of TNF may be responsible for the increasing of BUN and creatinine levels seen after renal I/R and that pretreatment of renal donors with FK506 may improve renal function in the immediate post-transplant period.

Nutrition and brain injury

The patient with head injury must overcome central and systemic insults. In addition to the head injury itself, the patient suffers a systemic metabolic response to injury. Both of these insults can affect the patient's ability to survive and recover. During the past decade, investigators have described the systemic metabolic result identified by hypermetabolism, hypercatabolism, the acute-phase response, decreased immunocompetence, hyperglycemia, increased counterregulatory hormone levels, increased ventricular fluid and serum cytokine levels, and altered gastric function. During the next decade, investigators will attempt to modulate this response by manipulating the types of nutrients administered, use of pharmacologic and physiological agents, and administration of growth factors.

FK 506 reduces the injury experienced following renal ischemia and reperfusion

The effect of FK 506 pretreatment on renal ischemia and reperfusion (I/R) injury was investigated. Adult male rats were assigned to one of two groups (20 animals each). Group 1 (controls) received 0.5 mL saline while group 2 received FK 506 (0.3 mg/kg) intravenously 24 h prior to the induction of renal ischemia. After a 60-min period of ischemia of the right kidney, a left nephrectomy was performed. Blood for BUN, creatinine, and tumor necrosis factor (TNF) was obtained prior to ischemia and on days 1, 2, 3, 5, 7, and 10. All surviving animals were sacrificed at day 10. FK 506 pretreatment reduced the serum levels of BUN (p less than .02), creatinine (p less than .02) and TNF (p less than .05) as compared to that seen in controls. Based upon these data, it appears that: (a) renal ischemia induces the release of TNF; (b) FK 506 pretreatment inhibits TNF production; and (c) FK 506 reduces renal injury association with I/R.

Increased plasma and ventricular fluid interleukin-6 levels in patients with head injury

The cytokine interleukin-6 (IL-6) plays a major role in initiating the acute phase response, especially in the production of acute phase reactants such as C-reactive protein. The objectives of this study were to determine whether plasma or ventricular fluid IL-6 levels were elevated at time of admission after head injury and whether plasma IL-6 levels related temporally to clinical improvement of levels of acute phase reactants. Thirty patients with Glasgow Coma Scale (GCS) scores of 3 through 10 were observed for 15 days after head injury. Peak elevation of plasma IL-6 occurred on admission (85 +/- 12 U/ml; normal level is less than 2 U/ml) and then decreased during the hospital course to a level of 29 +/- 4 U/ml on day 15. Plasma IL-6 levels decreased significantly faster in patients with admission peak 24-hour GCS scores of 8 through 10 compared with patients with GCS score less than 8 (p less than 0.01). Patients had markedly elevated and variable ventricular fluid IL-6 levels on admission (mean 3880 +/- 2022 U/ml; normal, less than 2 U/ml). A temporal relationship was found between plasma IL-6 levels and multiple acute phase reactants thought to be mediated by IL-6. We conclude that plasma and ventricular fluid levels of IL-6 are elevated after head injury and that plasma IL-6 level is temporally related to acute phase reactants and clinical improvement. We suggest that IL-6 may play an etiologic role in many of the metabolic or nutritional sequelae of head injury.

Altered gastric emptying in the head-injured patient: relationship to feeding intolerance

Most patients with moderate to severe head injury initially do not tolerate enteral feedings postinjury. This intolerance is more prolonged than that found in patients suffering other types of trauma. The authors prospectively evaluated 12 patients with moderate to severe head injury (Glasgow Coma Scale score between 4 and 10) throughout their hospitalization for liquid gastric emptying as a possible mechanism for intolerance to enteral feeding. During Week 1, the majority of patients displayed a delay in gastric emptying. Patients also displayed an abnormal biphasic response (gastric emptying faster than normal during the early stage but prolonged later). By Week 2, many patients still had delayed and abnormal biphasic responses to gastric emptying. By Week 3, an improvement was observed with the majority of patients exhibiting rapid gastric emptying, but delays and abnormal biphasic responses were still seen. Patients who initially had rapid or normal gastric emptying tolerated full-strength full-rate feedings significantly earlier compared with those who experienced delayed gastric emptying (8.5 +/- 0.5 days vs. 13.7 +/- 3.2 days, p less than 0.001). All patients tolerated full-strength full-rate feedings by Day 16 postinjury (range 7 to 16 days) except the two patients who displayed delayed gastric emptying for prolonged periods of time (mean 25 days). This is the first study to longitudinally evaluate gastric emptying following head injury. The authors suggest that patients with moderate to severe head injury often experience alterations in gastric emptying which may affect their ability to tolerate enteral feedings.

Metabolic management of the patient with head injury

Patients with severe head injury have a disruption in metabolic homeostasis that includes increased energy expenditure and increased protein catabolism. These changes have been suggested to occur secondary to steroid administration, immobility, and other factors. A review of investigations indicates that the head injury itself causes these metabolic changes, although steroid administration can further alter plasma amino acid changes. Altered plasma amino acid profiles after head injury may have an effect on substrate availability to the brain, bacterial translocation, and overall nitrogen balance. Patients with severe head injury have increased skeletal muscle efflux of amino acids. Lack of nutrient supplementation in these patients is associated with increased morbidity and mortality. Enteral nutrition is the preferred mode of feeding but often is not tolerated in the patient with head injury. Parenteral nutritional support can be given to these patients without worsening cerebral edema.

Gastrointestinal behavior of orally administered radiolabeled erythromycin pellets in man as determined by gamma scintigraphy

The behavior of single 250-mg doses of a multiparticulate form of erythromycin base (ERYC(R)), each including five pellets radiolabeled with neutron-activated samarium-153, was observed by gamma scintigraphy in seven male subjects under fasting and nonfasting conditions. The residence time and locus of radiolabeled pellets within regions of the gastrointestinal tract were determined and were correlated with plasma concentrations of erythromycin at coincident time points. Administration of food 30 minutes postdosing reduced fasting plasma erythromycin Cmax and area under the plasma erythromycin versus time curve (AUC) values by 43% and 54%, respectively. Mean peak plasma concentration of erythromycin (Cmax) in the fasting state was 1.64 micrograms/mL versus 0.94 micrograms/mL in the nonfasting state. Total oral bioavailability, as determined by mean AUC (0-infinity) of the plasma erythromycin concentration versus time curve, was 7.6 hr/micrograms/mL in the fasted state, versus 3.5 hr/micrograms/mL in the nonfasting state. Mean time to peak plasma erythromycin concentration (tmax) in the fasting state was 3.3 hours, versus 2.3 hours in the nonfasting state. Plasma concentrations of erythromycin in both fasting and nonfasting states were within acceptable therapeutic ranges. Evidence provided by this study: 1) indicates that pellet erosion and absorption of active erythromycin base begins when the enteric-coated pellets reach the highly vascular mucosa of the jejunum and proximal ileum, and is essentially completed within the ileum, with a significant portion absorbed in the medial-to-distal ileum; 2) confirms that acceptable therapeutic plasma levels of erythromycin are attained in nonfasting subjects (Cmax = 0.94 microgram/mL) and that superior plasma erythromycin concentrations (Cmax = 1.64 micrograms/mL) are achieved by administration of the dose on an empty stomach 1 to 2 hours before or after meals; 3) corroborates other comparative studies reporting greater fasting bioavailability with this multiparticulate dosage form of erythromycin base than with reference single tablet or particle-in-tablet formulations; and 4) indicates that neutron activation of stable isotopes incorporated as a normal excipient in industrially-produced formulations provides an effective means for in vivo evaluation of dosage forms through gamma scintigraphy.

Brain injury and nutrition

This review has discussed the current status of metabolic alterations and demands, nutrient administration, and nutritional assessment of the head-injured patient. More work is necessary in all areas to further describe and ascertain the nutritional requirements of these patients. Future research in this area should involve specific nutrient requirement, modification of the acute-phase response, and possibly administration of growth factors.

Nutrition and severe brain injury

Patients with severe brain injuries have increased energy expenditures and urinary nitrogen excretion. Hypozincemia, hypoferremia, increased levels of acute phase proteins, depressed levels of negative acute phase proteins, and weight loss are common in these patients. The specific mediators of these responses are not known. Nutritional support may beneficially affect outcome in these patients, but enteral feedings are often not tolerated in the acute phase of injury. Animal investigations suggest that total parenteral nutrition and hyperglycemia may increase neuronal injury and worsen outcome. We review the current literature on nutritional support of brain-injured patients and examine the premises on which nutrition supplementation are based. More work is needed to define the metabolic responses and nutritional requirements of patients who sustain central nervous system injury.

Intolerance to enteral feeding in the brain-injured patient

Calorie and protein supplementation improves nutritional status. This support may improve outcome and decrease morbidity and mortality in acutely brain-injured patients. Investigators have observed a poor tolerance to enteral feedings after brain injury and have noted that this persists for approximately 14 days postinjury. This delay has been attributed to increased gastric residuals, prolonged paralytic ileus, abdominal distention, aspiration pneumonitis, and diarrhea. In the present investigation, 23 brain-injured patients with an admission 24-hour peak Glasgow Coma Scale (GCS) score between 4 and 10 were studied for 18 days from hospital admission. The mean duration from injury to initiation of full-strength, full-rate enteral feeding was 11.5 days. Seven of the 23 patients tolerated enteral feedings within the first 7 days following hospital admission (mean 4.3 days), four patients tolerated feedings between 7 and 10 days postadmission (mean 9 days), and 12 patients did not tolerate feedings until after 10 days postinjury (mean 15.9 days). There was a marginally significant relationship between low GCS scores on admission and length of days to enteral feeding tolerance (p = 0.07). A significant inverse relationship was observed between daily peak intracranial pressure (ICP) and time to tolerance of feedings (p = 0.02). There was no significant relationship between feeding tolerance and days to return of bowel sounds (p = 0.12). Serum albumin levels decreased during the investigation (mean +/- standard error to the mean: 3.2 +/- 0.12 gm/dl on Day 1; 2.7 +/- 0.23 gm/dl on Day 16; normal = 3.5 to 5.0 gm/dl), whereas the percentage of patients tolerating feedings increased over the course of the study. The authors conclude that patients with acute severe brain injury do not adequately tolerate feedings via the enteral route in the early postinjury period. Tolerance of enteral feeding is inversely related to increased ICP and severity of brain injury. It is suggested that parenteral nutritional support is required following brain injury until enteral nutrition can be tolerated.

Phenobarbital induction and acetaminophen hepatotoxicity: resistance in the obese Zucker rodent

The obese Zucker rodent appears to lack a significant induction response after phenobarbital pretreatment. Induction of the hepatic cytochrome P-450 system with phenobarbital is known to enhance acetaminophen hepatotoxicity. The purpose of this study was to evaluate the influence of phenobarbital enzyme induction on acetaminophen hepatotoxicity in the obese and lean Zucker rodent. A preliminary study was performed evaluating the pharmacokinetics of acetaminophen in both the obese and lean Zucker rats. Data were utilized to calculate appropriate loading doses of acetaminophen during the subsequent hepatotoxicity study. Phenobarbital enzyme-inducing regimens were administered p.o. to achieve similar steady-state phenobarbital plasma concentrations. Control rats received appropriate placebo solutions. Serum hepatic transaminase enzymes and histologic evidence of hepatocellular necrosis were utilized to evaluate hepatic damage after p.o. administration of 1300 mg of acetaminophen to both obese and lean Zucker rats. Obese Zucker control animals had approximately 2.5 times the total hepatic glutathione content compared to their lean control (164.9 +/- 43.2 vs. 65.3 +/- 18.4 mumol/whole liver). Obese Zucker animals receiving only acetaminophen showed a trend toward a reduced incidence of hepatocellular necrosis compared to similarly treated lean littermates. Obese Zucker rodents pretreated with phenobarbital had an even more pronounced resistance to acetaminophen-induced hepatocellular necrosis (P less than .01) when compared to similarly treated lean littermates. Thus, acetaminophen hepatotoxicity is reduced in the obese Zucker rat and pretreatment with phenobarbital offers further protection against hepatocellular damage. We suggest that the previously unrecognized increase in hepatic glutathione plays a major role in the resistance of the obese Zucker rat to acetaminophen hepatotoxicity.

The metabolic response to brain injury

Every year several million people sustain brain injury. The development of an optimal metabolic and nutritional support program for brain-injured patients relies on an understanding of the metabolic response and nutritional complications that occur with brain injury. Severely brain injured patients have increased serum and urine levels of norepinephrine, epinephrine, and cortisol. These patients also have increased oxygen consumption and urinary nitrogen excretion. This group has observed hypozincemia, hyperzincuria, increased serum C-reactive protein and copper concentrations, and hypoalbuminemia in nonsteroid-treated severely brain-injured patients. Experimental head injury produces interleukin-1 (IL-1) of brain origin. This cytokine mediates many of the aspects of the acute phase response, including all of the metabolic abnormalities reported by our group. IL-1, when administered intracerebroventricularly to experimental animals, appears to have enhanced biological activity compared to that administered systemically. Interleukin-1 activity has been found in significant amounts in the intraventricular fluid of head-injured patients. We suggest that IL-1 acts in concert with traditional stress hormones such as epinephrine, norepinephrine, and cortisol to produce the profound metabolic disturbances observed in the head-injured patient.

Metabolic and nutritional sequelae in the non-steroid treated head injury patient

Energy production, substrate oxidation, serum protein levels, and weight change were studied in 16 non-steroid treated patients with severe head injury. Patients were evaluated during an average of 31.3 days from hospital admission to discharge. The mean measured energy expenditure (MEE) was 1.40 +/- 0.5 times predicted energy expenditure. Caloric balance [calories received = calories expended] was achieved by the 2nd week. Despite caloric balance and the administration of at least 1.5 g of protein per kg of body weight per day, the mean nitrogen balance was negative. There was a positive nitrogen balance in only 2 patients. These patients received a mean of 1.43 times the MEE in total kilocalories and 2.3 g of protein per kg of body weight. Fat and protein oxidation exceeded protein and fat administration for 3 weeks postinjury. Albumin levels dropped from a mean of 3.09 +/- 0.2 on admission to 1.98 +/- 0.4 within 2 weeks. The initial retinol binding protein levels were within the normal range, and the levels increased over time. There was marked weight loss (mean, 15.6 +/- 5.9 lb). Head injury induces a profound traumatic response identified by increased energy expenditure, a negative nitrogen balance, weight loss, hypoalbuminemia, and altered substrate oxidation. This response seems to be caused by the head injury alone and is not due to the administration of corticosteroids.

Abnormal polyunsaturated fatty acid patterns of serum lipids in alcoholism and cirrhosis: arachidonic acid deficiency in cirrhosis

Patterns of polyunsaturated fatty acids of serum phospholipids were measured for groups of alcoholics without cirrhosis, alcoholics with cirrhosis, cirrhotics without alcoholism, and a control population. Alcoholics without cirrhosis showed increased polyunsaturated fatty acids derived from linoleic and linolenic acids, but in cirrhotics these products were decreased. Alcoholism accentuated the abnormal polyunsaturated fatty acid pattern of cirrhosis. In alcohol abuse without cirrhosis, the level of 20:3 omega 9 (20 acyl carbon atoms:3 double bonds, omega, 9 carbon atoms beyond last double bond) was significantly increased, despite adequate levels of linoleic and arachidonic acids. Liver involvement appears necessary for development of deficiencies of polyunsaturated fatty acids in serum phospholipids, of which arachidonic acid deficiency is of the largest magnitude.