Phosphoinositide 3-kinase is involved in the induction of the human sperm acrosome reaction downstream of tyrosine phosphorylation

In somatic cells phosphoinositide 3-kinase (PI 3-kinase) is activated upon interaction with both receptor tyrosine kinases (RTK) and G- proteins resulting in the production of moieties involved in the inositol phospholipid signalling pathway. As G proteins, RTK and the inositol phospholipids have all been implicated in the human sperm acrosome reaction, experiments were carried out to determine whether PI 3-kinase was also involved in this phenomenon. Wortmannin is a selective inhibitor of PI 3-kinase and was shown to significantly inhibit the acrosome reaction induced by both mannose-bovine serum albumin (mannose-BSA) (10, 50 and 100 nM) and a polyclonal antibody raised against an extracellular region of the sperm zona receptor kinase (ZRK, at 100 nM only). Wortmannin did not inhibit the A23187- or progesterone-induced acrosome reaction. These results suggest that PI 3- kinase is involved in the human sperm acrosome reaction. The levels of tyrosine phosphorylation of sperm proteins as detected by Western blotting using antiphosphotyrosine antibodies was not affected by wortmannin in agonist (A23187 and mannose-BSA)-stimulated spermatozoa. This indicated that PI 3-kinase operates downstream of tyrosine phosphorylation in the signal transduction cascade which leads to the human sperm acrosome reaction.      

Magnetic resonance angiography

Pulse sequences that permit selective detection of moving spins in a magnetic resonance image have been developed. Experiments were performed by the authors to produce projected angiographic data without the use of contrast agents, with the intensity of each image pixel determined by the macroscopic velocity of the detected spins. With this method, suppression of nonmoving spins is essentially complete, yielding a high dynamic range in signal intensity for detected vessels. Selective detection of moving spins is not dependent on pulsatile flow. Consequently, not only arterial structures, but also venous structures can easily be visualized. High-resolution angiographic images can be obtained by combining the flow experiment with surface coil techniques.     

Pharmacokinetics of apomorphine in parkinsonian patients

Summary— Apomorphine, a dopamine agonist, has been used efficiently in parkinsonian patients to treat severe levodopa-induced on-off phenomenon. Motor improvement has been obtained both with continuous subcutaneous (SC) infusions, and multiple SC injections. So as to assist in the understanding of the clinical results, we studied the peripheral pharmacokinetics of apomorphine in 20 patients after intravenous (IV) or SC injections in the anterior abdominal wall and in the thigh at various doses, or SC infusion. Plasma apomorphine levels were measured by high-performance liquid chromatography with electrochemical detection. After an SC injection in the abdominal wall, the T_max was brief (16 ± 11 min) the drug was rapidly cleared from the plasma and had a short plasma half-life (69.7 ± 25.8 min). The AUC was similar following SC and IV injections, suggesting that apomorphine was completely absorbed from subcutaneous tissue. Inter-subject variability in drug absorption was large. We noticed a trend towards a more complete absorption following injection in the abdominal wall rather than in the thigh. In patients chronically treated by continuous SC infusion, the apparent plasma half-life was five times longer than that following SC or IV injections. These pharmacokinetic data may explain the rapid onset and brief duration of clinical effects, and the usefulness of individual titration for intermittent SC apomorphine injections, and the smoother motor response obtained with continuous SC infusions.     

Recovery of contact hypersensitivity responses following murine bone marrow transplantation: comparison of gamma-irradiation and busulfan as preparative marrow-ablative agents

Bone marrow transplantation (BMT) is often followed by significant morbidity and mortality due to protracted immunodeficiency. We have hypothesized that the bone marrow-ablative regimen may delay the recovery of normal immune function following transplantation by impairing the interaction of host endothelial cells with circulating graft-derived lymphocytes. This report compares the relative effects of busulfan (an alkylating drug) and gamma-irradiation on the tissue- specific localization potential of lymphocytes and the eventual recovery of immune function within syngeneic murine transplant recipients. Localization of normal lymphocytes into peripheral lymph nodes of irradiated BMT recipients was markedly less (less than 50%) than in busulfan-treated or normal mice over the first 2 months post- BMT. This finding correlated with irradiation-induced endothelial cell edema and microvascular occlusions within lymphocyte-receptive areas of the nodal microvasculature. The effect of both preparative regimens on the recovery of contact hypersensitivity (CHS) was also analyzed. This response recovered more quickly (between 1 and 2 months) in busulfan- pretreated animals. Further experiments demonstrated that the decrease in CHS responsiveness appeared, in part, related to a depression in the capacity of lymphocytes to localize into skin sites of antigen deposition within irradiated mice. The impairment of tissue-specific lymphocyte localization may represent a novel mechanism by which whole body irradiation can contribute to delayed immunologic reconstitution following bone marrow transplantation.     

The chronic effects of fish oil with exercise on postprandial lipaemia and chylomicron homeostasis in insulin resistant viscerally obese men

Background

The purpose of this study was to determine the effects of the pre-workout supplement Assault? (MusclePharm, Denver, CO, USA) on upper and lower body muscular endurance, aerobic and anaerobic capacity, and choice reaction time in recreationally-trained males. Subjective feelings of energy, fatigue, alertness, and focus were measured to examine associations between psychological factors and human performance.

Methods

Twelve recreationally-trained males participated in a 3-week investigation (mean +/- SD, age: 28 +/- 5 y, height: 178 +/- 9 cm, weight: 79.2 +/- 15.7 kg, VO_2max: 45.7 +/- 7.6 ml/kg/min). Subjects reported to the human performance laboratory on three separate occasions. All participants completed a baseline/familiarization day of testing that included a maximal graded exercise test for the determination of aerobic capacity (VO_2max), one-rep maximum (1-RM) for bench and leg press to determine 75% of 1-RM, choice reaction tests, and intermittent critical velocity familiarization. Choice reaction tests included the following: single-step audio and visual, one-tower stationary protocol, two-tower lateral protocol, three-tower multi-directional protocol, and three-tower multi-directional protocol with martial arts sticks. Subjects were randomly assigned to ingest either the supplement (SUP) or the placebo (PL) during Visit 2. Subjects were provided with the cross-over treatment on the last testing visit. Testing occurred 20 min following ingestion of both treatments.

Results

Significant (p < 0.05) main effects for the SUP were observed for leg press (SUP: 13 ± 6 reps, PL: 11 ± 3 reps), perceived energy (SUP: 3.4 ± 0.9, PL: 3.1 ± 0.8), alertness (SUP: 4.0 ± 0.7, PL: 3.5 ± 0.8), focus (SUP: 4.1 ± 0.6, PL: 3.5 ± 0.8), choice reaction audio single-step (SUP: 0.92 ± 0.10 s, PL: 0.97 ± 0.11 s), choice reaction multi-direction 15 s (SUP: 1.07 ± 0.12 s, PL: 1.13 ± 0.14 s), and multi-direction for 30 s (SUP: 1.10 ± 0.11 s, PL: 1.14 ± 0.13 s).

Conclusions

Ingesting the SUP before exercise significantly improved agility choice reaction performance and lower body muscular endurance, while increasing perceived energy and reducing subjective fatigue. These findings suggest that the SUP may delay fatigue during strenuous exercise.     

Studies on levamisole--induced agranulocytosis

Widespread clinical trials of leavo-tetramisole (levamisole) as an immunopotentiating agent in rheumatoid arthritis, metastatic carcinoma, and immunodeficiency states have been complicated by agranulocytosis (AGC) in 2.5%-13% of patients. Other than a relationship with prolonged high dosage, very little is known regarding the pathogenesis of levamisole-induced AGC. Whereas leukoagglutination was negative, fluorochromatic microgranulocytotoxicity (GCY) tests were positive with serum from 10 of 10 acutely neutropenic patients. The antibody was IgM, reacted with 100% of unrelated granulocytes, but not with T or B lymphocytes. Some sera also reacted with monocytes and the myeloid cell line, K-562. Tests for antigen-antibody complexes or cold autoantibodies were negative. Although clinical evidence strongly suggests a haptene (drug) mechanism, in vitro mixing experiments were also negative. An alternative choice parallels the model of aldomet- induced Coombs'-positive hemolytic anemia. Finally, GCY first became positive 2-3 mo prior to the onset of AGC on two patients, suggesting the possibility of identifying those at risk well before the onset of neutropenia.     

Cutaneous T cell lymphoma: characterization by monoclonal antibodies

Monoclonal antibodies to human T cells permit the characterization of the surface phenotype of cutaneous T cell lymphoma (CTCL). The majority of CTCL cells are reactive with OKT1 and OKT3 monoclonals, which identify peripheral T cells and mature thymocytes. The neoplastic cells also react with OKT4, which recognizes the inducer T cell subset; they are, however, unreactive with OKT5 monoclonal, which identifies cytotoxic/suppressor T cell subsets. These data are in agreement with previous functional studies demonstrating that CTCL is a neoplasm of inducer (helper) T cells.     

Stem cell factor enhances the survival but not the self-renewal of murine hematopoietic long-term repopulating cells

The effects of stem cell factor (SCF) have been tested on a murine bone marrow subpopulation (RH123lo, Lin-, Ly6A/E+) that is highly enriched for long-term hematopoietic repopulating cells. SCF maintained cells from this population with long-term repopulating ability for up to 10 days in vitro. However, compared with freshly isolated cells, the level of engraftment in vivo by the cultured cells declined during the in vitro culture period, suggesting that SCF alone was unable to stimulate the self-renewal of long-term repopulating cells. By direct visualization of cultures, only small numbers of cells survived and rarely underwent cell division. However, SCF did directly stimulate proliferation of a population (Rh123med/hi,Lin-,Ly6A/E+) enriched for short-term repopulating cells. These data suggest that stem cell differentiation is associated with the development of mitogenic activity by SCF at least in some progenitor cell populations.     

The repopulation potential of fetal liver hematopoietic stem cells in mice exceeds that of their liver adult bone marrow counterparts

Varying, limiting numbers of unseparated or purified cells (Ly-5.1), either from 14.5-day-old fetal liver (FL) or from adult bone marrow (BM) were coinjected with 10(5) unseparated BM cells (Ly-5.2) into lethally irradiated adult C57B1/6 recipients (Ly-5.2). The kinetics of donor cell repopulation of the lymphoid and myeloid compartments by Ly- 5.1+ donor hematopoietic stem cells (ie, competitive repopulation units [CRU]) were monitored at various time points after the transplantation by Ly-5 analysis of the peripheral white blood cells (WBC). Recipients that had received on average less than 2 adult BM or FL CRU did not show a significant difference in the level of donor-reconstitution when analyzed 4 weeks after the transplantation, However, at 8 and 16 weeks, the FL recipients showed a significantly higher percentage of donor- derived nucleated peripheral blood cells than did the recipients of adult BM cells. Analysis of individual mice showed that approximately 80% of the recipients of FL CRU showed an increase in mature WBC output between 4 and 8 weeks after transplantation, whereas this occurred in less than 40% in the recipients of adult BM cells. In addition to this effect on mature cell output, the cellularity of the reconstituted BM was significantly higher in recipients of FL CRU than in recipients of adult BM CRU, even at 7 to 9 months after transplantation, which is consistent with an increased clonal expansion of FL CRU. When marrow cells from primary recipients of FL CRU were injected into secondary recipients, a significantly higher percentage of these mice showed donor-reconstitution of their lymphoid and myeloid compartments (P < .01) and to a greater extent (P < .008) as compared with mice that had received marrow cells from primary recipients of similar numbers of adult BM CRU. Taken together, these results show that individual FL CRU exhibit a greater proliferative activity in vivo than similar cells from adult BM that is accompanied by a greater production of daughter CRU.