Systematic literature review of the risk factors, comorbidities, and consequences of hypogonadism in men.

The objective of this review was to summarize the literature on the risk factors, comorbidities, and consequences of male hypogonadism, which is defined as a syndrome complex that includes biochemical confirmation of low testosterone (T) and the consistent symptoms and signs associated with low T. A systematic literature search was performed in PubMed/MEDLINE, EMBASE, Cochrane Library for articles published in the last 10 years on risk factors, comorbidities, and consequences of male hypogonadism. Of the 53 relevant studies identified, nine examined potential risk factors, 14 examined potential comorbidities, and 30 examined potential consequences of male hypogonadism. Based on studies conducted in Asia, Australia, Europe, and North & South America, the important factors that predicted and correlated with hypogonadism were advanced age, obesity, a diagnosis of metabolic syndrome (MetS), and a poor general health status. Diabetes mellitus was correlated with hypogonadism in most studies, but was not established as a risk factor. Although diseases, such as coronary heart disease, hypertension, stroke, and peripheral arterial disease did not predict hypogonadism, they did correlate with incident low T. The data reviewed on potential consequences suggest that low T levels may be linked to earlier all-cause and cardiovascular related mortality among men. This literature review suggests that men with certain factors, such as advanced age, obesity, MetS, and poor general health, are more likely to have and develop hypogonadism. Low levels of T may have important long-term negative health consequences.

Hepatitis B immunization of healthy elderly adults: relationship between naïve CD4+ T cells and primary immune response and evaluation of GM-CSF as an adjuvant.

The efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) to enhance the primary immune response to hepatitis B vaccine was studied in healthy elderly with young volunteers included as controls in this double-blind, placebo-controlled trial of GM-CSF as an immune adjuvant. Naïve T-helper cells (CD4+CD45RA+) were determined at baseline. Forty-five healthy elderly (average age, 74 years) and 37 healthy young controls (average age, 28 years) were randomized. Hepatitis B vaccine was administered at 0, 1, and 6 months. GM-CSF as a single injection of either 80 microg or 250 microg with the first and second doses of hepatitis B vaccine. In this trial GM-CSF did not enhance antibody responses. However, the antibody responses were dramatically different between these two groups: 35/35 young developed a protective titer versus 19/45 elderly (P < 0.0001). In addition, the mean logarithm of anti-hepatitis B antibody level in the 35 young who completed the study was 3.17 (log mIU/ml) but only 2.21 in the 19 elderly responders (P < 0.0001). Naïve T-helper cells differed significantly between the two groups: the mean percentage of CD4+CD45RA+ T cells was 47.9% versus 35.0% (P < 0.0001) in the young and elderly volunteers respectively. Naïve T cells also differed significantly between elderly who did or did not respond to HBV (39.9% vs. 31.7%, P = 0.039). Using linear regression, age, and percent naive, CD4 T cells were determined to significantly influence the anti-hepatitis B antibody response, but sex and dose of GM-CSF did not. For a two-parameter model: logarithm of antibody titer = (-0.038 x age in years) + (0.031 x % naïve CD4T cells) + 2.68; adjusted r2 = 0.605 and P < 0.0001. However, age had a larger effect than naive CD4 T cells, i.e., in comparing young and elderly groups the log antibody titer decreased by 1.73 due to the increase in age but only 0.40 due to the decrease in naive CD4 T cells. Thus, there was a large effect of age that could not be explained by the quantitative change in the naïve T-helper cells.

Direct capillary electrophoretic detection of carbohydrate-deficient transferrin in neat serum.

Transferrin, an iron transport protein found in serum and cerebrospinal fluid, is known to be microheterogeneous with respect to its carbohydrate and sialic acid content. The forms of transferrin deficient in sialic acid and/or carbohydrate, termed carbohydrate-deficient transferrin (CDT), have been of clinical interest for almost two decades as a result of the initial finding that elevated CDT concentrations are associated with chronic, excessive alcohol abuse. We demonstrate the utility of capillary electrophoresis for examining the CDT sialoform profile via the direct electrophoresis of serum. The need for negligible preelectrophoresis sample preparation and absence of postelectrophoresis processing dramatically decreases analysis time compared to slab gel-based separations. Using a fluorocarbon-coated capillary containing a hydroxyethyl cellulose/borate buffer, the high resolution separation of serum components is effected in less than 30 min. Under these conditions, the beta region proteins (including transferrin) are well resolved from the alpha-2 and gamma zone proteins in a window where the individual transferrin sialoforms can be detected. The usefulness of this method is demonstrated with the electrophoresis of serum from subjects known to be either non-alcoholic and alcoholic.

Ionizing radiation potentiates the induction of nitric oxide synthase by interferon-gamma and/or lipopolysaccharide in murine macrophage cell lines. Role of tumor necrosis factor-alpha.

Macrophages respond to infection or injury by changing from a "resting" cellular phenotype to an "activated" state defined by the expression of various cytotoxic effector functions. Regulation of the transition from a resting to an activated state is effected by cytokine and/or pathogenic signals. Some signals do not directly induce activation, but instead "prime" the macrophage to respond more vigorously to a second signal. One example of this priming phenomenon involves induction of nitric oxide (NO) synthesis by the enzyme nitric oxide synthase (NOS2). Our experiments indicate that low doses (1-5 Gy) of ionizing radiation can enhance the induction of enzymatically active NOS2 by IFN-gamma or LPS in J774.1 and RAW264.7 murine macrophage cell lines. Radiation alone did not produce this induction, rather, it was effective as a priming signal; cells exposed to radiation produced more NO when a second signal, either IFN-gamma or LPS, was applied 24 h later.

Evaluation of the hydroxylamine Tempol-H as an in vivo radioprotector.

Nitroxides are stable free radical compounds that protect against the toxicity of reactive oxygen species in vitro and in vivo. Tempol (Aldrich, Milwaukee, WI, USA) is a cell-permeable hydrophilic nitroxide and has been shown to be an in vitro and in vivo radioprotector. The limitations of Tempol as a systemic radioprotector are that it causes substantial reductions in arterial blood pressure when administered intravenously and is associated with seizure activity. Furthermore, Tempol is rapidly reduced to its hydroxylamine form, Tempol-H, which limits the period of time the active form of the nitroxide is available for radioprotection. Based on initial pharmacological and blood pressure experiments performed in mice, we hypothesized that the systemic administration of Tempol-H in vivo would lead to an equilibration between Tempol and Tempol-H that would limit the toxicity of the nitroxide and provide in vivo radioprotection. Tempol-H was administered in increasing doses via an intraperitoneal route to C3H mice. The maximally tolerated dose was found to be 325 mg/kg. The whole-blood pharmacology of Tempol-H was investigated with electron paramagnetic resonance spectroscopy. These studies demonstrated the appearance of Tempol in whole blood immediately after intraperitoneal injection, suggesting that rapid oxidation of Tempol-H to Tempol takes place in vivo. Although the peak concentration of Tempol in whole blood after administration of Tempol-H did not reach the same levels as those observed when Tempol is administered, the whole-blood levels of Tempol were similar by 10 min after injection. Tempol-H provided protection against the lethality of whole-body radiation in C3H mice at 30 d with a dose modification factor of 1.3, which is similar to the results obtained with Tempol. Hemodynamic measurements in C3H mice after intravenous injection showed that Tempol-H produced little effect on blood pressure or pulse compared with Tempol. Tempol-H is a systemic in vivo radioprotector of C3H mice and is associated with less hemodynamic toxicity than Tempol.

Three-dimensional whole body imaging of spin probes in mice by time-domain radiofrequency electron paramagnetic resonance.

Imaging of stable paramagnetic spin probes in phantom objects and in vivo was evaluated using a RF time domain EPR spectrometer/imager operating at 300 MHz. Projections were collected using static magnetic field gradients and images were reconstructed using filtered back-projection techniques. Results from phantom objects containing approximately 10(17) spins of stable paramagnetic probes with single narrow EPR spectra provide three-dimensional spatial images with resolution better than 2 mm. When the spin probe was administered to mice, the spin probe accumulation was temporally observed in the thoracic, abdominal, and pelvic regions. A three-dimensional image (from 144 projections) from a live mouse was collected in 5 min. Using fiducial markers, the spin probe accumulation in organs such as liver, kidney, and bladder could be observed. Differences in the oxygen status between liver and kidney were observed from the EPR images from mice administered with spin probe, by treating the time-domain responses with convolution difference approach, prior to image reconstruction. The results from these studies suggest that, with the use of stable paramagnetic spin probes and time-domain RF EPR, it is possible to perform in vivo imaging on animals and also obtain important spatially resolved physiologic information.

Hemodynamic effect of the nitroxide superoxide dismutase mimics.

Reactive oxygen species play critical roles in a number of physiologic and pathologic processes. Nitroxides are stable free radical compounds that possess superoxide dismutase (SOD) mimetic activity and have been shown to protect against the toxicity of reactive oxygen species in vitro and in vivo. Tempol, a cell-permeable hydrophilic nitroxide, protects against oxidative stress and also is an in vitro and in vivo radioprotector. In the course of evaluating the pharmacology and toxicity of the nitroxides, Tempol and another nitroxide, 3-carbamoyl-PROXYL (3-CP), were administered intravenously in various concentrations to miniature swine. Tempol caused dose-related hypotension accompanied by reflex tachycardia and increased skin temperature. Invasive hemodynamic monitoring with Swan Ganz catheterization (SGC) confirmed the potent vasodilative effect of Tempol. However, 3-CP had no effect on porcine blood pressure. The hemodynamic effects of Tempol and 3-CP are discussed in the context of differential catalytic rate constants for superoxide disumation that may impact systemic nitric oxide (NO) levels and lead to vasodilation. These findings are consistent with a role for the superoxide ion in the modulation of blood pressure and have potential implications for the systemic use of nitroxides.

Cytomegalovirus seropositivity is associated with the expansion of CD4+CD28- and CD8+CD28- T cells in rheumatoid arthritis.

OBJECTIVE: Previous researchers have found expansion of CD4+CD28- T cells in patients with rheumatoid arthritis (RA) compared to age matched controls, and have identified expanded clones of autoreactive cells within this population. We examine the association of prior cytomegalovirus (CMV) infection (positive serum anti-CMV IgG) with the percentage of CD4+CD28- T cells and CD8+CD28- T cells in patients with RA. METHODS: A total of 45 patients (36 women, 9 men), mean age of 59 years, with definite RA were studied. RESULTS: In this group 28 patients were seropositive for CMV and 17 seronegative. Seropositive and seronegative subjects did not differ significantly in age, sex, medication use, or severity of disease. Joint count, Health Assessment Questionnaire, pain score, patient global assessment, physician global assessment, and presence of extraarticular disease served to assess disease severity. Expression of CD4/CD28/CD57 and CD8/CD28/CD57 on lymphocytes was determined by 3 color flow cytometry. (CD28 and CD57 are reciprocally related.) CD4+CD28-CD57+ T cells were expanded only in CMV seropositive patients. CONCLUSION: The "carrier" phenotype that has been hypothesized based on a 2 population model for the distribution of CD4+CD28- T cells in RA can be explained by prior infection with CMV.

Induction of nitric oxide production in infiltrating leukocytes following in vivo irradiation of tumor-bearing mice.

Nitric oxide (NO) has been implicated both in regression and progression of tumors due to its production by both tumor cells and infiltrating leukocytes. Ionizing radiation causes the regression of tumors, and can augment the production of NO by macrophages in vitro. We examined the cellular and systemic production of NO in mice in which radiation-resistant RIF-1 fibrosarcoma cells were implanted subcutaneously and were then either irradiated or sham-treated at the tumor site. Ten days following implantation of the tumors, CD45- tumor cells and CD45+ leukocytes were derived from resected tumors immediately after irradiation with 60 Gy, a dose previously reported to reduce tumor growth. Leukocytes from tumors of irradiated hosts produced spontaneously up to four-fold more NO than did either leukocytes from unirradiated mice or CD45- tumor cells from either unirradiated or irradiated mice. Between days 10-14 following tumor implantation, serum NO2-/NO3- increased in both irradiated and unirradiated mice to an equal extent, culminating in levels higher than those of non-tumor-bearing mice. Though NO production is elevated in macrophages treated with 1-10 Gy of radiation in vitro, higher doses may be required by tumor-infiltrating macrophages in vivo and thus may indicate that tumor-infiltrating macrophages are deactivated.

Analysis of the neuroprotective effects of various nitric oxide donor compounds in murine mixed cortical cell culture.

Nitric oxide (NO) has been implicated in both the pathogenesis of and protection from NMDA receptor-mediated neuronal injury. This apparent paradox has been attributed to alternate redox states of nitrogen monoxide, whereby, depending on the redox milieu, nitrogen monoxide can be neuroprotective via nitrosation chemistry or react with superoxide to form secondary toxic species. In our murine mixed cortical cell culture system, the NONOate-type NO donors diethylamine/NO complex sodium (Dea/NO), (Z)-[N-(3-ammoniopropyl)-N-(n-propyl)amino]diazen-1-ium++ +-1,2-diolate (Papa/NO), and spermine/NO complex sodium (Sper/NO), as well as the S-nitrosothiols S-nitroso-L-glutathione (GSNO) and S-nitroso-N-acetyl-D,L-penicillamine (SNAP) (NO+ equivalents), decreased NMDA-induced neuronal injury in a concentration-dependent manner. 8-Bromo-cyclic GMP did not mimic the inhibitory effects of the donors, suggesting that the neuroprotection was not the result of NO-stimulated neuronal cyclic GMP production. Furthermore, neuronal injury induced by exposure of cultures to H2O2 was not altered by the presence of Dea/NO, indicating the absence of a direct antioxidant effect. NONOates did, however, reduce NMDA-stimulated uptake of 45Ca2+, whereas high potassium-induced 45Ca2+ accumulation, a measurement of entry via voltage-gated calcium channels, was unaffected. The parallel reduction of 45Ca2+ accumulation and NMDA neurotoxicity by NONOates mimicked that seen with an NMDA receptor antagonist. Electrochemical measurements of NO via an NO-sensitive electrode demonstrated that neuroprotective concentrations of all donors produced appreciable amounts of NO over the 5-min time frame. Determination of the formation of NO+ equivalents, as assessed by N-nitrosation of 2,3-diaminonaphthylene, revealed little or no observable N-nitrosation by Sper/NO, GSNO, and SNAP with significant N-nitrosation observed by Papa/NO and Dea/NO. However, addition of ascorbate (400 microM) effectively prevented the nitrosation of 2,3-diaminonaphthylene produced by Dea/NO and Papa/NO without altering their neuroprotective properties or their effects on 45Ca2+ accumulation. Present results indicate that the intrinsic NO/NO+ characteristics of NO donor compounds may not be a good predictor of their ability to inhibit NMDA receptor-mediated neurotoxicity at the cellular level.

The use of Zn-desferrioxamine for radioprotection in mice, tissue culture, and isolated DNA.

Redox-active metals mediate oxidative injury and might also potentiate radiation damage. The iron chelator desferrioxamine (DFO), which diminishes oxidative damage in many chemical and biological systems as well as in human subjects, has a controversial role in radiobiology and reportedly acts both as a radiosensitizer and a radioprotector. The present research focused on the radioprotective activity of its zinc complex. Zn-DFO was studied using three test systems differing by their complexities: isolated DNA from pUC 19 plasmid, cultured V79 Chinese hamster cells, and C3H mice. Zn-DFO (0.5-2 mM) protected isolated DNA against gamma-radiation better than each of its components alone; however, neither Zn-DFO nor DFO (50-100 microM) alone affected the radiation sensitivity of cultured cells. With total body irradiation, Zn-DFO, but not DFO alone at 100 micromol/kg body weight, administered to mice 30 min before irradiation provided significant radioprotection (P < 0.01). Zn-DFO had an LD(50/30) of 10.3 Gy, whereas DFO and vehicle alone had LD(50/30) of 8.03 Gy and 7.91 Gy, respectively. The effect of Zn-DFO on the hemodynamic parameters in mice did not differ from that of the vehicle (saline) alone. This excludes the explanation that the radioprotective activity of Zn-DFO results from its effect on oxygen levels. In addition to the possible direct effect of Zn, other potential modes of action underlying the radioprotective activity of Zn-DFO might involve a displacement of iron and its substitution by zinc, a greater proximity of the drug to DNA, and less likely an improved penetration of the drug into cells because of its structure. The failure of Zn-DFO to protect cells in tissue cultures indicates that it has some systemic role in the whole animal, possibly due to a prolonged half-life in the animal's circulation.

In vivo radioprotection and effects on blood pressure of the stable free radical nitroxides.

PURPOSE: The purpose of this study was to screen several water soluble nitroxides for in vivo radioprotection, to evaluate their pharmacology, and to measure the effect of nitroxides on systemic blood pressure as a means of exploring the mechanism of in vivo radioprotection. METHODS AND MATERIALS: A number of water soluble nitroxides were screened for in vivo radioprotection in C3H mice at a single radiation dose. Selected nitroxides were administered by the intraperitoneal route 10 minutes prior to a whole body radiation dose of 9 Gy. Electron paramagnetic resonance spectroscopy (EPR) was used to measure whole blood levels of nitroxides. The nitroxides were evaluated for effects on systemic blood pressure in C3H mice. RESULTS: All of the nitroxides studied demonstrated radioprotection compared to saline-treated controls. The 6-membered piperidine ring nitroxides including Tempol were reduced to the inactive hydroxylamine rapidly over 10-20 minutes. The 5-membered ring nitroxides were reduced more slowly over time. The 5-membered ring 3-carbamoyl-PROXYL did not produce a substantial decrease in systemic blood pressure after intraperitoneal administration compared to the other nitroxides studied. 3-carbamoyl-PROXYL was further evaluated over a range of whole body radiation doses and was found to provide radioprotection. CONCLUSION: All of the nitroxides studied provided radioprotection. In vivo radioprotection for all of the compounds except 3-carbamoyl-PROXYL may be at least partially explained by the induction of hypotension and bone marrow hypoxia. 3-carbamoyl-PROXYL provided in vivo radioprotection similar in magnitude to Tempol and had little effect on blood pressure compared to the other nitroxides. Other mechanisms for radioprotection, including scavenging of free radicals are likely. 3-carbamoyl-PROXYL should be evaluated further as a systemic radioprotector.

Ionizing radiation potentiates the induction of nitric oxide synthase by IFN-gamma and/or LPS in murine macrophage cell lines: role of TNF-alpha.

Macrophages are activated to become cytotoxic by a highly coordinated set of cytokine signals. Ionizing radiation can mimic cytokine signals and lead to enhanced states of activation. We tested the ability of gamma-radiation, alone and with interferon-gamma (IFN-gamma) and/or lipopolysaccharide (LPS), to induce nitric oxide (NO) production in J774.1 and RAW264.7 murine macrophages. NO was induced weakly, moderately, or strongly by IFN-gamma alone, LPS alone, or IFN-gamma + LPS, respectively. Radiation alone (0.5-50 Gy) did not induce NO, but enhanced NO production in a dose-dependent manner (0.5-5 Gy) when cells were exposed to IFN-gamma or LPS 24 h post-irradiation. Immunoblots showed parallel induction of nitric oxide synthase (NOS2). Application of anti-tumor necrosis factor alpha (TNF-alpha) antibody before irradiation blocked induction of NO by IFN-gamma. We conclude (1) that irradiated cells produce more NO in response to either IFN-gamma or LPS and (2) that the increase is mediated by induction of TNF-alpha.

Body temperature alterations in hospitalized HIV/AIDS patients.

Because of the questions raised by the staff nurses regarding their observations of fever and alterations in body temperature in AIDS patients, a nursing research study was conducted to examine the incidence and degree of temperature elevation in hospitalized AIDS patients. Study findings suggest that temperature elevation and fever are common occurrences in hospitalized HIV/AIDS patients, although the fever may be self-limiting. An elevation in the white blood cell count was not seen, making fever in HIV/AIDS patients different than other medical/surgical patients. Phenomena noted by staff nurses in the clinical setting should be verified by nursing research because the data derived from nursing observation can be used in designing nursing interventions.

The role of nitric oxide chemistry in cancer treatment.

Over the last decade the role of nitric oxide (NO) in various disease states has become apparent. In cancer, NO plays a variety of roles which are at times contradictory. On one hand, NO is involved in different etiological mechanisms as well as promoting tumor growth. Yet, NO derived from leukocytes plays a seminal role in their tumoricidal activity. In cancer treatment, NO also has diverse effects. Whereas in vitro, NO can enhance the cytotoxic efficacy of some chemotherapeutic agents as well as radiation, NO donors can provide whole body protection against these same agents. This manuscript will discuss some mechanisms involved with NO and cancer treatment modalities and the potential application of these findings to cancer therapy.

In vivo electron paramagnetic resonance imaging of tumor heterogeneity and oxygenation in a murine model.

Nitroxides are redox-sensitive probes, which are useful in noninvasively delineating tissue heterogeneity especially with respect to metabolic activity and tissue oxygenation. Recent studies have shown that nitroxides are in vitro and in vivo radioprotectors and selectively protect normal tissue compared to tumor tissue. It has been postulated that the basis for selective radioprotection of normal tissues is greater bioreduction of nitroxides in tumor tissue compared to normal tissue. The aim of the present study was to investigate the distribution and lifetime of nitroxides in tumor and normal tissues. Mice were implanted with tumor cells (RIF-1) in the thigh, and the tumor was allowed to grow to about 10-15 mm in diameter. After i.v. infusion of nitroxides, in vivo electron paramagnetic resonance spectroscopy and imaging of the tumor were performed using a specially built bridged-loop surface resonator. The pharmacokinetic and spatial distribution of the nitroxides in tumor tissue were followed and compared with those in normal tissue. Three-dimensional spatial images showed significant heterogeneity in the nitroxide distribution as well as reduction rates. The nitroxide reduction rates were significantly higher in tumors than in the normal tissue. Measurements using spin label oximetry showed a substantial difference in the level of oxygenation between normal tissue (muscle) and tumor tissue. Average pO2 levels in tumor tissue were found to be 3-fold lower than in a corresponding volume of normal tissue. The lower pO2 levels in tumor compared to normal tissue may explain the more rapid reduction of nitroxides in these tissues. This study demonstrates that electron paramagnetic resonance imaging can perform noninvasive anatomical as well as functional imaging and provide in vivo physiological information regarding cellular metabolism in tumor and normal tissues.