Acute-phase protein α-1-acid glycoprotein is negatively associated with feed intake in postpartum dairy cows.

α-1-Acid glycoprotein (AGP) is an acute-phase protein that may suppress dry matter intake (DMI), potentially by acting on the leptin receptor in the hypothalamus. Our objectives were to characterize plasma AGP concentration and associations with DMI during the transition period, and to determine the utility of AGP to identify or predict cows with low DMI. Plasma samples (n = 2,086) from 434 Holstein cows in 6 studies were analyzed on d -21, -13 ± 2, -3, 1, 3, 7 ± 1, 14 ± 1, and 21 ± 1 relative to parturition. A commercially available ELISA kit specific for bovine AGP was validated, and 2 internal controls were analyzed on each plate with interplate variation of 15.0 and 17.3%, respectively. Bivariate analysis was used to assess the relationship between AGP and DMI. For significant associations, treatment(study) was added to the model, and quadratic associations were included in the model if significant. Plasma AGP concentration (±SEM) increased from 213 ± 37.3 µg/mL on d -3 to 445 ± 60.0 µg/mL on d 14. On d 3, AGP was associated negatively with DMI in a quadratic manner for wk 1 and wk 2 and linearly for wk 3. Day 7 AGP was associated negatively with DMI in a quadratic manner for wk 2 and linearly for wk 3. Similarly, d 14 AGP was negatively associated with DMI for wk 3 and wk 4. As d 3 AGP concentration increased over the interquartile range, a calculated 1.4 (8.5%), 0.5 (2.7%), and 0.4 (1.9%) kg/d reduction in predicted DMI was detected during wk 1, 2, and 3, respectively. Using bivariate analysis, d 3 AGP explained 10% of the variation in DMI during wk 1. We explored the clinical utility of d 3 AGP to diagnose low DMI, defined as wk 1 DMI >1 standard deviation below the mean. Receiver operating characteristic analysis identified a threshold of 480.9 µg/mL, providing 76% specificity and 48% sensitivity (area under the curve = 0.60). Limited associations occurred between AGP and blood biomarkers; however, AGP was associated with plasma haptoglobin concentration postpartum and incidence of displaced abomasum, retained placenta, and metritis. These results demonstrate a negative association between plasma AGP concentration and DMI in early-postpartum dairy cows, although its diagnostic performance was marginal. Further investigation into whether AGP directly suppresses DMI in dairy cattle is warranted.

Enzyme-Targeted Nanoparticles for Delivery to Ischemic Skeletal Muscle.

The targeted delivery of enzyme-responsive nanoparticles to specific tissues can be a valuable, minimally invasive approach for imaging or drug delivery applications. In this study, we show for the first time enzyme-directed assembly of intravenously (IV) delivered nanoparticles in ischemic skeletal muscle, which has applications for drug delivery to damaged muscle of the type prevalent in peripheral artery disease (PAD). Specifically, micellar nanoparticles are cleavable by matrix metalloproteinases (MMPs), causing them to undergo a morphological switch and thus aggregate in tissues where these enzymes are upregulated, like ischemic muscle. Here, we demonstrated noninvasive in vivo imaging of these IV-injected nanoparticles through near-infrared dye labeling and in vivo imaging (IVIS) particle tracking in a rat hindlimb ischemia model. Polymer peptide amphiphilic nanoparticles were synthesized and optimized for both MMP cleavage efficiency and near-IR fluorescence. Nanoparticles were injected 4 days after unilateral hindlimb ischemia and were monitored over 28 days using IVIS imaging. Nanoparticles targeted to ischemic muscle over healthy muscle, and ex vivo biodistribution analysis at 7 and 28 days post-injection confirmed targeting to the ischemic muscle as well as off target accumulation in the liver and spleen. Ex vivo histology confirmed particle localization in ischemic but not healthy muscle. Altering the surface charge of the nanoparticles through addition of zwitterionic dye species resulted in improved targeting to the ischemic muscle. To our knowledge, this is the first study to demonstrate the targeted delivery and long term retention of nanoparticles using an enzyme-directed morphology switch. This has implications for noninvasive drug delivery vehicles for treating ischemic muscle, as no minimally invasive, non-surgical options currently exist.

Micro- and Nanoparticles for Treating Cardiovascular Disease.

Cardiovascular disease, including myocardial infarction (MI) and peripheral artery disease (PAD), afflicts millions of people in Unites States. Current therapies are insufficient to restore blood flow and repair the injured heart or skeletal muscle, respectively, which is subjected to ischemic damage following vessel occlusion. Micro- and nano-particles are being designed as delivery vehicles for growth factors, enzymes and/or small molecules to provide a sustained therapeutic stimulus at the injured tissue. Depending on the formulation, the particles can be injected directly into the heart or skeletal muscle, or accumulate at the site of injury following an intravenous injection. In this article we review existing particle based therapies for treating MI and PAD.

Fabrication and characterization of injectable hydrogels derived from decellularized skeletal and cardiac muscle.

Biomaterials, which can contain appropriate biomechanical and/or biochemical cues, are increasingly being investigated as potential scaffolds for tissue regeneration and/or repair for treating myocardial infarction, heart failure, and peripheral artery disease. Specifically, injectable hydrogels are touted for their minimally invasive delivery, ability to self-assemble in situ, and capacity to encourage host tissue regeneration. Here we present detailed methods for fabricating and characterizing decellularized injectable cardiac and skeletal muscle extracellular matrix (ECM) hydrogels. The ECM derived hydrogels have low cellular and DNA content, retain sulfated glycosaminoglycans and other extracellular matrix proteins such as collagen, gel at physiologic temperature and pH, and assume a nanofibrous architecture. These injectable hydrogels are amenable to minimally invasive, tissue specific biomaterial therapies for treating myocardial infarction and peripheral artery disease.

Injectable biomaterials for adipose tissue engineering.

Adipose tissue engineering has recently gained significant attention from materials scientists as a result of the exponential growth of soft tissue filler procedures being performed within the clinic. While several injectable materials are currently being marketed for filling subcutaneous voids, they often face limited longevity due to rapid resorption. Their inability to encourage natural adipose formation or ingrowth necessitates repeated injections for a prolonged effect and thus classifies them as temporary fillers. As a result, a significant need for injectable materials that not only act as fillers but also promote in vivo adipogenesis is beginning to be realized. This paper will discuss the advantages and disadvantages of commercially available soft tissue fillers. It will then summarize the current state of research using injectable synthetic materials, biopolymers and extracellular matrix-derived materials for adipose tissue engineering. Furthermore, the successful attributes observed across each of these materials will be outlined along with a discussion of the current difficulties and future directions for adipose tissue engineering.

Effects of resveratrol on the autophosphorylation of phorbol ester-responsive protein kinases: inhibition of protein kinase D but not protein kinase C isozyme autophosphorylation.

The natural product resveratrol is a potent antagonist of phorbol ester-mediated tumor promotion and in vitro cellular responses to phorbol-ester tumor promoters, but it is only weakly inhibitory against the phosphorylation of conventional exogenous substrates by phorbol ester-responsive protein kinase C (PKC) isozymes. In this report, we compare the effects of resveratrol against the autophosphorylation reactions of PKC isozymes versus the novel phorbol ester-responsive kinase, protein kinase D (PKD). We found that resveratrol inhibits PKD autophosphorylation in a concentration-dependent manner, but has only negligible effects against the autophosphorylation reactions of representative members of each PKC isozyme subfamily (cPKC-alpha, -beta(1), and -gamma, nPKC-delta and -epsilon, and aPKC-zeta). Resveratrol was comparably effective against PKD autophosphorylation (IC(50) = 52 microM) and PKD phosphorylation of the exogenous substrate syntide-2 (IC(50) = 36 microM). The inhibitory potency of resveratrol against PKD is in line with the potency of resveratrol observed in cellular systems and with its potency against other purified enzymes and binding proteins that are implicated in the cancer chemopreventive activity of the polyphenol. Thus, PKD inhibition may contribute to the cancer chemopreventive action of resveratrol.

A phase I trial of a modified, dose intensive FAMTX regimen (high dose 5-fluorouracil+doxorubicin+high dose methotrexate+leucovorin) with oral uridine rescue.

BACKGROUND: Dose intensification of 5-fluorouracil (5-FU) is complicated by increased toxicity. 5-FU is a fluorine-substituted pyrimidine analog of uracil. In preclinical studies, administration of oral uridine (Ur) has been shown to allow for dose intensification of 5-FU with enhancement of its antitumor activity. Therefore, a Phase I trial was designed aimed at dose intensification of 5-FU as a component of a modified 5-FU-doxorubicin-methotrexate (FAMTX) regimen using oral Ur rescue. METHODS: Methotrexate (MTX) was administered to all patients at a fixed dose of 1.5 g/m2. MTX was followed 24 hours later by escalating doses of 5-FU starting at 800 mg/m2 with leucovorin rescue. Cycles of 5-FU and MTX were repeated every 15 days. Every other cycle, patients received doxorubicin. "Adria cycles") at a dose of 30 mg/m2. Oral Ur was administered at a dose of 8 gm/m2 every 6 hours for 12 doses. In the first phase of the study, patients received Ur only if they developed Grade 3 or 4 hematologic toxicity. In the second phase, all patients received Ur 24 hours after 5-FU on all cycles. RESULTS: Without Ur rescue, the maximum tolerated dose (MTD) of 5-FU was 900 mg/m2 on the Adria cycles and 1.1 gm/m2 on the non-Adria cycles. With Ur, the MTD of 5-FU increased to 1.2 gm/m2 on the Adria cycles and to 1.6 gm/m2 on the non-Adria cycles. CONCLUSIONS: In this modified FAMTX regimen, oral Ur administration allowed for dose-intensification of 5-FU, with a 33% increase in the MTD of 5-FU on the Adria cycles and a 45% increase in the MTD of 5-FU dose on the non-Adria cycles.

Cancer chemotherapy in the elderly.

Gastrointestinal malignancies are very common in the elderly of the U.S. There is controversy about the role of chemotherapy in these elderly patients because of the impression that this population experiences greater toxicity while deriving lesser benefit. Though definitive data is lacking regarding many aspects of chemotherapy in the elderly, some general observations can be made: (a) most chemotherapy agents do not have increased toxicity in the elderly; (b) dosing and regimen should be based more on functional parameters rather than chronologic age; (c) chemotherapy for advanced gastrointestinal malignancies is in general of marginal efficacy and can be potentially toxic, regardless of age; and (d) better prospective studies focusing on the efficacy, toxicity, and quality of life effects of chemotherapy in the elderly should be performed. We review the literature regarding chemotherapy pharmacology, efficacy, and organ-specific toxicity of agents used in gastrointestinal malignancies in the context of these principles.

Mobilization and rejection of Individual Ready Reserve personnel in Operations Desert Shield/Storm at a U.S. Army Quartermaster post.

The individual Ready Reserve (IRR) is an important component of the U.S. Army's total combat force. After Operations Desert Shield/Storm, we investigated the mobilization of soldiers with combat service support specialties from the IRR to a quartermaster training post. In the initial 2 weeks of activation prior to assignment and deployment, the soldiers went through medical and administrative screening, and general and specialized military training. During this period, a sizable portion (one-quarter) of IRR troops who reported to duty were rejected for a variety of reasons (overweight, inadequate dependent arrangements, etc.) and did not remain on active duty. Potential changes to the policies that led to these rejections are discussed.

Desert Shield deployment and social problems on a U.S. Army combat support post.

We undertook a study of selected mental health-related services at a combat support post to determine if stress levels surrounding Operations Desert Shield/Desert Storm had an effect on the utilization of these services. Our measure was the problem rate formed by adding the visits to the alcohol and drug service and the social work service. The findings (not all of which reached statistical significance in our small study) were that the problem rates were higher in those units which deployed, both before and after deployment. The pre-deployment differences in age, rank, and race between those soldiers deployed and not deployed is a finding which may help to account for the difference between units. There was a transient, but not sustained, problem rate increase immediately following return home for those units which deployed. Implications for mental health-related services staffing and directions for further research are discussed.

Phase II trial of gemcitabine in patients with advanced gastric cancer.

BACKGROUND: Approximately 22,000 new cases of gastric cancer are diagnosed each year in the United States, most of which are advanced disease and thus are not curable by surgery. Chemotherapy has had little impact on patient survival. Consequently, the evaluation of new agents is needed. Gemcitabine, a cytosine arabinoside analogue, was evaluated in a Phase II trial to assess its efficacy in previously untreated patients with advanced gastric cancer. METHODS: Patients were treated with weekly gemcitabine, 800 mg/m2, for 3 consecutive weeks, followed by a 1-week rest period. Eighteen patients were enrolled. Fifteen patients were evaluable for response; 2 patients refused therapy before the completion of one cycle of treatment, and one patient was found to have nonmeasurable disease. RESULTS: No major objective responses were seen. Two minor responses occurred. One patient with a minor response was removed from the study at his request after ten cycles of treatment. The other patient remains on the study with stable disease at more than 17 months. Toxicities on this study were mild. Median leukocyte count and platelet nadirs were 5.0 (range, 2.2-51.0) and 234,000/microliters (range, 59,000-554,000/microliters), respectively. CONCLUSION: Gemcitabine at this dose and schedule has no significant antitumor activity in gastric cancer.

Edatrexate in patients with soft tissue sarcoma. Activity in malignant fibrous histiocytoma.

BACKGROUND: Chemotherapy has had little impact on the natural history of soft tissue sarcoma, and often is associated with serious toxicity. Edatrexate, an investigational antifolate, is active in patients with lung cancer, and has cytotoxic activity in human sarcoma cell lines. METHODS: Edatrexate was administered to 36 patients with measurable, advanced soft tissue sarcoma who had not previously received chemotherapy. The drug was given weekly for 5 weeks, then every other week. The initial dose, 80 mg/m2, was escalated by 10 mg/m2 every 2 weeks in the absence of toxicity. Eleven patients had leiomyosarcoma, 7 had malignant fibrous histiocytoma (MFH), and 5 had liposarcoma; the remainder of cell types included hemangiopericytoma (4), angiosarcoma (3), synovial (2), spindle cell (2), extraosseous chondrosarcoma (1), and fibrosarcoma (1). RESULTS: Thirty-five patients are evaluable. Partial response (PR) was seen in five of the seven patients with MFH; no other major responses occurred. Overall, the response frequency was 14% (two-sided 95% confidence interval, 3% to 26%). Median duration of PR was 6 months (range, 4-18 months). One patient had a minor tumor regression, and six had stable disease. Myelosuppression was generally mild; only three patients had grade 3 hematologic toxicity. Modification of dose or schedule was required in 50% of patients for mucositis. Fatigue was a common toxicity, seen in 66% of patients, but was tolerable in the majority. A rash was seen in 46% of patients; one patient had hepatic toxicity. CONCLUSIONS: Overall, the activity of edatrexate in this study, dominated by patients with either visceral or vascular sarcoma, was poor. However, the responses observed in patients with metastatic MFH suggests that further evaluation of edatrexate in patients with soft tissue sarcoma is warranted.

Chemotherapy of metastatic breast cancer in the elderly. The Piedmont Oncology Association experience [see comment].

OBJECTIVE: To determine the effect of age on treatment outcome in women with metastatic breast cancer treated with chemotherapy. DESIGN: Case-comparison study of patients with metastic breast cancer treated in five clinical trials of the Piedmont Oncology Association. SETTING: University and private practice physicians participating in the Piedmont Oncology Association clinical trials in the southeastern United States. PATIENTS: Seventy patients 70 years of age or older were compared with 60 patients aged 50 through 69 years and 40 patients less than 50 years of age. All patients were ambulatory or capable of self-care, with adequate hematologic, renal, and hepatic function. INTERVENTIONS: Treatment with multidrug chemotherapy regimens. MAIN OUTCOME MEASURES: Response to treatment, time to disease progression, survival, and toxic effects. RESULTS: Pretreatment characteristics including race, performance status, disease-free interval, prior therapy, sites of metastatic disease, and number and dominant sites of metastases were similar for the three age groups. The response rates for the younger-than-50, 50-through-69, and 70-or-older age groups were 40%, 31%, and 29%, respectively (P = .53). There were no significant differences in time to disease progression or survival for patients in the three age groups. Estimates for time to progression and survival were 9.1 and 17.9 months, 6.2 and 12.8 months, and 7.2 and 14.2 months, respectively. Toxic effects, dose delivery, and dose delays were also similar for all three age groups. CONCLUSIONS: Women 70 years of age or older who were enrolled in these trials were similar to their younger counterparts in response rates, time to disease progression, survival, and toxic effects. Women in this age group should not be excluded, based on age alone, from clinical trials involving chemotherapy for advanced breast cancer.

Quantitation of S-adenosylmethionine decarboxylase protein.

A method for the specific labeling of the active site of S-adenosylmethionine decarboxylase was developed. The method consisted of incubating cell extracts with 3H-decarboxylated S-adenosylmethionine and sodium cyanoborohydride in the presence of a spermidine synthase inhibitor. Under these conditions, S-adenosylmethionine decarboxylase was labeled specifically and stoichiometrically. This procedure was used (a) to establish that the subunit molecular weight of S-adenosylmethionine decarboxylase from rat liver, prostate, and psoas and from mouse SV-3T3 cells was 32 000, (b) to titrate the number of active molecules of S-adenosylmethionine decarboxylase in various cell extracts, and (c) to provide a high specific activity labeled preparation of S-adenosylmethionine decarboxylase for use in radioimmunoassay of this enzyme. Competitive radioimmunoassays using this labeled antigen had a sensitivity such that 3 fmol (0.1 ng) of enzyme protein could be quantitated. The rapid loss of S-adenosylmethionine decarboxylase which occurred when SV-3T3 cells were exposed to exogenous polyamines was shown to be due to a rapid decline in the amount of enzyme protein measured both by titration of the active site and by radioimmunoassay.

Adolescent suicide and the classroom teacher.

Adolescent suicide is a phenomenon of epidemic proportions, constituting the third leading cause of death in this age group. Various theories of suicide are reviewed and the attention to family variables discussed. These theoretical models indicate the multidisciplinary nature of the problem - that is, that adolescent suicide requires a medical, psychological, social and educational approach to the problem. Since school plays a major role in the lives of adolescents, it offers an avenue of approach to adolescent suicide. A list of behavioral changes indicative of emotional distress is provided for teachers for use in identification and referral. Teachers should also serve an educational function. Discussion of suicide dispels myths and modifies the likelihood of an attempt. Several suggestions concerning how school personnel may intervene are provided.

High-frequency pulsed Doppler ultrasound: a new tool for microvascular surgery.

A wide variety of surgical procedures now depend on the suture repair of vessels smaller than 1.5 mm. The need persists, however, for a rapid and objective test of patency that is atraumatic. Small-vessel studies indicate that the high-frequency (20 MHz) pulsed Doppler velocimeter is particulary well suited for this task. We have evaluated the ability of such a system to quantitate stenosis produced by partial ligation in a rat model, and report its initial successful use as an intraoperative tool to determine the quality of microvascular anastomoses.