Evaluation of the effects of altitude on biological signatures of inflammation and anxiety- and depressive-like behavioral responses

Over sixteen million people suffer from a depressive episode annually in the United States, with females affected at twice the rate of males. Little is known about the effects of exposure to high altitude on the risk of development of major depressive disorder, despite reports of higher suicide rates at higher altitudes. We hypothesize that exposure to hypobaric hypoxia at high altitude increases endophenotypes of self-directed suicidal violence, including biological signatures of chronic inflammation and vulnerability to anxiety-like and depressive-like behavioral responses in a sex-specific manner. Biological signatures of inflammation, including granulocyte:lymphocyte ratios, monocyte cell counts, and monocyte:lymphocyte ratios were assessed using complete blood count data, anhedonia, and anxiety- and depressive-like behavioral responses were evaluated. We assessed biological signatures of inflammation and behavioral responses in the open-field test, sucrose preference test, and modified Porsolt forced swim test in young adult male and female Long-Evans and Sprague Dawley rats. All tests were conducted near sea level (374 ft [114 m] elevation) and at moderate-high altitude (5430 ft [1655 m] elevation) during acclimation periods of one, two, three, four, and five weeks following shipment from a sea level animal breeding facility (N = 320, n = 8 per group). Exposure to moderate-high altitude induced a biological signature of increased inflammation, as evidenced by main effects of altitude for: 1) increased granulocyte:lymphocyte ratio; 2) increased count and relative abundance of circulating monocytes; and 3) increased monocyte:lymphocyte ratios. Exposure to moderate-high altitude also increased anhedonia as assessed in the sucrose preference test in both male and female rats, when data were collapsed across strain and time. Among male and female Long Evans rats, exposure to moderate-high altitude increased immobility in the forced swim test, without changing anxiety-like behaviors in the open-field test. Finally, granulocyte:lymphocyte ratios were correlated with anhedonia in the sucrose preference test. These data are consistent with the hypothesis that hypobaric hypoxia at moderate-high altitude induces persistent endophenotypes of self-directed suicidal violence including biological signatures of inflammation, anhedonia, and depressive-like behavioral responses.

Effects of Pelleting, Irradiation, and Autoclaving of Rodent Feed on MPV and MNV Infectivity

Murine norovirus (MNV) and mouse parvovirus (MPV) are among the most common adventitial viruses seen in laboratory mice, and infections arise in barrier facilities despite rigorous biosecurity programs. Some authors have implicated nonsterilized feed as a source of MPV in rodent facilities, but none have conclusively documented viral particles in the feed. In this study, we hypothesized that both viruses can resist the pelleting process but not subsequent irradiation or autoclaving, thus revealing a potential source of outbreaks in rodent facilities. To test this hypothesis, we contaminated powdered feed with 10-fold concentrations of MNV and MPV and fed it to both Swiss Webster (SW) and C57BL/6NTac (B6) mice to determine a 'powdered ID50' according to seroconversion over a 28-d period. We repeated the experiment by using powdered feed that we contaminated with increasing viral doses (as no. of powdered ID50) and subsequently pelleted; from these results, we determined a 'pelleted ID50.' Finally we assessed the effect of irradiation and autoclaving on contaminated pellets by using the same experimental design. The powdered ID50 was relatively low and identical in both mouse strains (2.51 × 10² pfu) for MNV but higher in B6 (copy number, 3.20 × 106) than SW (3.98 × 10⁴ copies) for MPV. As hypothesized, mice were infected by contaminated rodent feed despite the pelleting process. Indeed, pelleting resulted in a 1- to 2-log increase in ID50 in both strains for MNV and MPV. Irradiation and autoclaving of infected pellets effectively prevented seroconversion of mice exposed to all doses of MNV, whereas a single mouse seroconverted at the highest dose of MPV (1.35 × 107 copies). These data suggest that both MNV and MPV remain infectious after conditions reproducing the rodent chow pelleting process and that nonsterilized rodent chow might be a source of viral outbreaks.

Hypercortisolemia and Depressive-like Behaviors in a Rhesus Macaque (Macaca mulatta) Involved in Visual Research

A 10-y-old cranially implanted rhesus macaque (Macaca mulatta) involved in visual research was presented for dull mentation and weight loss. Physical examination revealed alopecia and poor body conditioning, and bloodwork revealed marked hypercortisolemia (23 μg/dL). Differential diagnoses for hypercortisolemia, weight loss, and alopecia included Cushing and pseudo-Cushing syndromes. To further evaluate hypercortisolemia, we compared the urine cortisol:creatinine ratio (UCCR) at baseline and after low-dose dexamethasone suppression (LDDS) testing in the presenting animal and healthy naïve and implanted working monkeys. At baseline, UCCR was 10 times higher in the presenting macaque (118.1 ± 7.1) than in naïve animals (12.5 ± 12.8) and 3 times higher than in healthy implanted working macaques (44.4 ± 6.9); however, levels were suppressed similarly by dexamethasone in both the presenting animal and healthy controls. In addition, healthy implanted working macaques had significantly higher baseline UCCR levels than naïve controls, suggesting chronic stress in working animals. Abdominal ultrasonography and radiographs of the presenting animal revealed marked bilateral adrenal mineralization but no overt adrenal tumor or hyperplasia. Overall, these results excluded endogenous Cushing syndrome and prompted us to evaluate different causes of pseudo-Cushing syndrome, including depression. Using videorecordings to evaluate behavior, we used published criteria for macaque models of depression models, including huddling, to make a presumptive diagnosis of depression. The macaque was treated with fluoxetine (2 mg/kg PO daily), provided increased environmental enrichment, and followed over time by regular UCCR assessment and videorecordings. The animal improved clinically and behaviorally, and UCCR returned to levels observed in working implanted macaques (44.4) after 8 wk of treatment. This case highlights the potential effect of research-related work on stress and pathologic behaviors in macaques and demonstrates the utility of UCCR and LDDS for screening behavioral and hypothalamic-pituitary-adrenal abnormalities in these animals.

Postoperative Analgesia Due to Sustained-Release Buprenorphine, Sustained-Release Meloxicam, and Carprofen Gel in a Model of Incisional Pain in Rats (Rattus norvegicus)

Postoperative analgesia in laboratory rats is complicated by the frequent handling associated with common analgesic dosing requirements. Here, we evaluated sustained-release buprenorphine (Bup-SR), sustained-release meloxicam (Melox-SR), and carprofen gel (CG) as refinements for postoperative analgesia. The aim of this study was to investigate whether postoperative administration of Bup-SR, Melox-SR, or CG effectively controls behavioral mechanical and thermal hypersensitivity in a rat model of incisional pain. Rats were randomly assigned to 1 of 5 treatment groups: saline, 1 mL/kg SC BID; buprenorphine HCl (Bup HCl), 0.05 mg/kg SC BID; Bup-SR, 1.2 mg/kg SC once; Melox-SR, 4 mg/kg SC once; and CG, 2 oz PO daily. Mechanical and thermal hypersensitivity were tested daily from day-1 through 4. Bup HCl and Bup-SR attenuated mechanical and thermal hypersensitivity on days 1 through 4. Melox-SR and CG attenuated mechanical hypersensitivity-but not thermal hypersensitivity-on days 1 through 4. Plasma concentrations, measured by using UPLC with mass spectrometry, were consistent between both buprenorphine formulations. Gross pathologic examination revealed no signs of toxicity in any group. These findings suggest that postoperative administration of Bup HCl and Bup-SR-but not Melox-SR or CG-effectively attenuates mechanical and thermal hypersensitivity in a rat model of incisional pain.

Adaptation and transmission of a duck-origin avian influenza virus in poultry species

A duck-origin avian influenza virus (AIV) was used to study viral adaptation and transmission patterns in chickens (Gallus gallus domesticus) and Pekin ducks (Anas platyrhynchos domesticus). Inoculated birds were housed with naïve birds of the same species and all birds were monitored for infection. The inoculating duck virus was transmitted effectively by contact in both species. Viruses recovered from infected birds showed mutations as early as 1 or 3 days after inoculation in chickens and ducks, respectively. Amino acid substitutions in hemagglutinin (HA) or deletions in neuraminidase (NA) stalk regions were identified in chicken isolates, but only substitutions in HA were identified in duck isolates. HA substitution-containing viruses replicated more efficiently than those with NA stalk deletions. NA deletion mutants were not recovered from contact chickens, suggesting inefficient transmission. Amino acid substitutions in HA proteins appeared in pairs in chickens, but were independent in ducks, indicating adaptation in chickens. In addition, our findings showed that a duck-origin virus can rapidly adapt to chickens, suggesting that the emergence of new epidemic AIV can be rapid.

Immune-related gene expression in response to H11N9 low pathogenic avian influenza virus infection in chicken and Pekin duck peripheral blood mononuclear cells

The duck and chicken are important hosts of avian influenza virus (AIV) with distinctive responses to infection. Frequently, AIV infections in ducks are asymptomatic and long-lasting in contrast to the clinically apparent and transient infections observed in chickens. These differences may be due in part to the host response to AIV infection. Using real-time quantitative PCR, we examined the expression of immune-related genes in response to low pathogenic AIV H11N9 infection in peripheral blood mononuclear cells (PBMC) isolated from the blood of chickens and Pekin ducks. While chicken PBMC expressed IL-1beta and IL-6 at high levels similar to mammalian species, duck PBMC expression levels were minimal or unchanged. Similarly, duck IFN-beta expression was nearly unaffected, whereas chicken expression was highly upregulated. Chicken IFN-gamma was expressed to higher levels than duck IFN-gamma, while IFN-alpha was expressed similarly by both species. IL-2 was elevated early in infection in duck PBMC, but returned to baseline levels by the end of the experiment; in contrast, IL-2 was weakly induced in chicken PBMC at late time points. TLR-7 and MHC class I molecule expressions were conserved between species, whereas duck MHC class II expression was downregulated and chicken expression was unchanged. These results show distinct PBMC expression patterns of pro-inflammatory cytokines and IFNs between species. The differences in pro-inflammatory cytokine and IFN expression reflect the asymptomatic and lasting infection observed in ducks and the tendency towards clinical signs and rapid clearance seen in chickens. These results highlight important differences in the host response to AIV of two species thought to be critical in the genesis and maintenance of epidemic strains of AIV.

Polyethylene glycol nephrotoxicity secondary to prolonged high-dose intravenous lorazepam

OBJECTIVE

To report a patient with a probable acute tubular necrosis (ATN) induced by chronic exposure to polyethylene glycol (PEG)-400 via long-term, massive dosage of intravenous lorazepam.

CASE SUMMARY

A 57-year-old man with a history of alcohol abuse was admitted to the intensive care unit for acute respiratory failure. Lorazepam therapy was initiated in anticipation of alcohol withdrawal. Dosages up to 18 mg/h were required to provide adequate sedation and optimize ventilation. On day 43, the patient developed oliguric ATN of unknown etiology. The cumulative intravenous lorazepam dose was 4089 mg, equivalent to approximately 220 mL of PEG-400. Blood urea nitrogen concentrations followed a pattern that paralleled lorazepam dosage increases and decreases. Protein and granular casts were evident in urinalyses performed on days 12 and 29. The patient eventually experienced complete recovery.

DISCUSSION

ATN associated with intravenous PEG was last reported in 1959 in 6 of 32 patients receiving a cumulative PEG-300 dose of 120-200 mL over 3-5 days via an intravenous nitrofurantoin preparation. Two of the 6 patients died. Chronic administration of intravenous PEG to rabbits over a 5-week period has caused cloudy swelling of the renal tubular epithelium, increased blood urea concentrations, and death in some animals.

CONCLUSIONS

ATN probably resulted from chronic PEG exposure via massive doses of lorazepam injection, possibly enhanced by concurrent administration of vancomycin.

Glycosylation and antigenic variation among Kunjin virus isolates

Previous studies have found Kunjin (KUN) virus isolates from within Australia to be genetically homogenous and that the envelope protein of the type strain (MRM61C) was unglycosylated and lacked a potential glycosylation site. We investigated the extent of antigenic variation between KUN virus isolates from Australia and Sarawak using an immunoperoxidase assay and a panel of six monoclonal antibodies. The glycosylation status of the E protein of each virus was also determined by N glycosidase F (PNGase F) digestion and limited sequence analysis. The results showed that KUN viruses isolated within Australia oscillated between three antigenic types defined by two epitopes whose expression was influenced by passage history and host cell type. In contrast an isolate from Sarawak formed a stable antigenic type that was not influenced by passage history and was distinct from all Australian isolates. PNGase F digestions of KUN isolates indicated that 19 of the 33 viruses possessed a glycosylated E protein. Nucleotide sequence of the 5' third of the E gene of selected KUN isolates revealed that a single base change in PNGase F sensitive strains changed the tripeptide N-Y-F (amino acids 154-156 of the published sequence) to the potential glycosylation site N-Y-S. Further analysis revealed that passage history also had a significant influence on glycosylation.

Degradation and inactivation of antitumor drugs

Chemical methods for the degradation of 11 antineoplastic drugs [etoposide, teniposide, bleomycin, mitomycin C, cisplatin, cis-dichloro-trans-dihydroxy-bis(isopropylamine) platinum IV (CHIP), cyclophosphamide, ifosfamide, carmustine, lomustine, and methotrexate] were investigated. The success of the degradation procedures was assessed by HPLC and degree of biological inactivation by mutagenicity assays. The most widely applicable procedure was oxidation with potassium permanganate or 5.25% sodium hypochlorite solution (bleach). Oxidation completely degraded and inactivated etoposide, teniposide, bleomycin, mitomycin C, and methotrexate. In addition, oxidation followed by nucleophilic substitution resulted in the complete degradation and inactivation of cyclophosphamide and ifosfamide. Although carmustine and lomustine were chemically degraded by treatment with acidic potassium permanganate, the resulting reaction mixtures remained mutagenic. Therefore, this procedure cannot be recommended. The platinum-containing compounds, cisplatin and CHIP, were rendered nonmutagenic by reaction with sodium diethyldithiocarbamate. These easily performed, relatively safe procedures can be used to prevent exposure to mutagenic wastes and spills in the hospital setting.

Treatment of chemical and biological warfare injuries: insights derived from the 1984 Iraqi attack on Majnoon Island

The potential use of chemical and biological weapons, while being banned by international treaties, has never been higher than now. The current Persian Gulf crisis, and the easy availability of these weapons by "terrorist nations," makes the danger all too real. The experience derived from the Iraqi attack on Majnoon Island demonstrates the devastating effects of these weapons when used during modern warfare. Exposure to the agents used during the 8 years of the Iran-Iraq War results in a triad of injuries: skin burns, ocular damage, and pulmonary distress. Specific antidotes are available for some agents used in warfare; however, the clinical presentation following exposure to the different toxins is extremely similar, making a bedside diagnosis of the specific agent involved almost impossible. The Majnoon Island experience has shown the value of prevention, when possible, and decontamination, of both casualties and equipment. The prompt implementation of general treatment strategies, as well as specific antidotes, are paramount for the successful management of patients after a chemical weapons attack.

Refractive-index measurements of the beta'' aluminas

The refractive indices of selected monovalent and divalent beta'' alumina single crystals are determined using prism refraction techniques. The birefringence is found to vary from uniaxial negative to uniaxial positive depending on the electronic polarizability of the exchanged ion. Thus, beta'' alumina is a novel material in which the magnitude and polarity of the birefringence can be tuned simply by ion exchange. The refractive-index data are used to predict an isoindex point (n(e) = n(0)) for the mixed-system Na(+)-Ag(+) beta'' alumina compositions.

Stability of dicloxacillin sodium oral suspension stored in polypropylene syringes

The stability of dicloxacillin sodium in oral suspension stored in clear polypropylene oral syringes was studied. Commercially available dicloxacillin sodium powder for oral suspension from a single lot was reconstituted according to the manufacturer's instructions and drawn into 5-mL clear polypropylene oral syringes. The syringes were divided into groups and stored at -20, 4, 25, 40, 60 or 80 degrees C. Two additional lots were similarly reconstituted, repackaged, and stored at 80 degrees C only to assess interlot variability. Powder in the original containers was similarly reconstituted according to the manufacturer's instructions, and the containers were divided into groups and stored with the syringes. Immediately after reconstitution and at specified times during storage, three syringes and the original containers at each storage temperature were removed, and their contents were analyzed for dicloxacillin sodium concentration using the Standard USP Iodometric Assay. Dicloxacillin sodium follows a first-order rate of degradation at temperatures of 40, 60, and 80 degrees C. The rate of degradation changes to a zero-order process at temperatures of 25, 4, and -20 degrees C. At all temperatures, degradation occurred more rapidly when the drug was repackaged into unit dose polypropylene oral syringes than in the manufacturer's original container. Dicloxacillin sodium reconstituted from powder as oral suspension and repackaged in clear polypropylene syringes was stable for no longer than 7, 10, and 21 days when stored under ambient, refrigerated, and frozen conditions, respectively.

Toxicity, immunosuppressive effects and carcinogenic potential of volatile nitrites: possible relationship to Kaposi's sarcoma

Volatile nitrite in the form of amyl nitrite was used for 100 years for the treatment of angina pectoris. In spite of recognized toxicity, its use in this form was considered safe. During the 1960s prescriptions were not required for purchase of amyl nitrite (called poppers) and its use for recreational purposes became popular. With reinstatement of the prescription requirement in 1969, non-medicinal, street-variety volatile nitrites were made commercially available in the form of mixtures of impure butyl and isobutyl nitrite; some of these preparations also included amyl nitrite. These products have been found to be profoundly immunosuppressive for human lymphocytes in vitro, and their by-products when metabolized into N-nitroso compounds have been known to be highly carcinogenic in many animal species. Recreational use of inhaled volatile nitrites is prevalent among male homosexuals and the compounds have been suspected as possible cofactors in Kaposi's sarcoma associated with the Acquired Immune Deficiency Syndrome (AIDS). This association could be explained by nitrite-induced vasodilation of rectal mucosal vessels providing a port of entry for a transmissible agent, by direct immunosuppression of the host allowing expression of a potentially oncogenic virus by co-carcinogenic effects of by-products by themselves or in conjunction with other putative cofactors such as cytomegalovirus. Nitrites should continue to be considered as a possible cofactor in the etiology of Kaposi's Sarcoma among male homosexuals and possibly those with other manifestations of AIDS.

Acquired immune deficiency syndrome and the management of associated opportunistic infections

Since the spring of 1981, more than 2300 cases of acquired immune deficiency syndrome (AIDS) have been reported from 41 states to the Centers for Disease Control. Cases also have been reported from 20 foreign countries, and reports are increasing at an alarming rate. More than 900 people (approximately 40 percent) have died of this disease. AIDS is characterized by skin test anergy to recall antigens, decreased T-helper subset, and inverted helper T-cell:suppressor T-cell ratios in the peripheral blood. Overt AIDS may be preceded by a prodrome that may last for many months and consists of fever, weight loss, and lymphadenopathy. The immune defect in AIDS permits the development of opportunistic infections caused by a number of organisms, including Pneumocystis carinii, Mycobacterium avium-intracellulare, Toxoplasma gondii, and various fungi. Certain malignancies also are associated with AIDS, in particular, Kaposi's sarcoma. Although the etiology of AIDS is unknown, the causative agent appears to be infectious. Lifestyle factors such as drug use and certain sexual activities may play a role. Currently, epidemiologists and others investigating the syndrome believe that AIDS can spread through sexual contact, blood products, or both. AIDS patients include homosexual males, users of intravenous drugs, immigrants from Haiti, hemophiliacs, female partners of males with AIDS, infants born to mothers who have AIDS, and persons who have received blood products from AIDS patients. Thus far, questions about AIDS outnumber the answers. Intensive research is being conducted to develop a rational approach to the treatment of AIDS and a better understanding of the relationship between the immune defense system and cancer.