Progressive infection in a subset of HIV-1-positive chimpanzees.

Chimpanzees are susceptible to infection with human immunodeficiency virus (HIV)-1; however, infected animals usually maintain normal numbers of CD4(+) T lymphocytes and do not develop immunodeficiency. We have examined 10 chronically infected HIV-1-positive chimpanzees for evidence of progressive infection. In addition to 1 animal that developed AIDS, 3 chimpanzees exhibit evidence of progressive HIV infection. All progressors have low CD4(+) T cell counts (<200 cells/microL), severe CD4:CD8 inversion, and marked reduction in interleukin-2 receptor expression by CD4(+) T cells. In comparison with HIV-positive nonprogressor chimpanzees, progressors have higher plasma and lymphoid virus loads, greater CD38 expression in CD8(+)/HLA-DR(+) T cells, and greater serum concentrations of soluble tumor necrosis factor type II receptors and beta2-microglobulin, all markers of HIV progression in humans. These observations show that progressive HIV-1 infection can occur in chimpanzees and suggest that the pathogenesis of progressive infection in this species resembles that in humans.

A pilot study examining patient response to a weight loss workbook designed to Be used in a family medicine outpatient setting.

This study measured patient response to a self-help weight loss workbook designed for use in an outpatient, family medicine practice. The primary measures were 2 follow-up telephone calls, the first at 1 week and the second at 1 month after the book was given to the patient. Initially, patients were enthusiastic about the book and had read it, and 24 (70%) intended to use it. On the other hand, at 1 month, only 8 (32%) of those called were actually using the book. Reasons for this change are explored.

Effect of modified ultrafiltration on plasma thromboxane B2, leukotriene B4, and endothelin-1 in infants undergoing cardiopulmonary bypass.

BACKGROUND: Plasma thromboxane B2 (TXB2), leukotriene B4 (LTB4), and endothelin-1 (ET-1) levels increase on cardiopulmonary bypass (CPB). Elevated levels of TXB2 and ET-1 have been correlated with postoperative pulmonary hypertension in infants undergoing repair of congenital heart defects. LTB4 is a potent chemotactic cytokine whose levels correlate with leukocyte-mediated injury. Modified ultrafiltration (MUF) has been associated with improved hemodynamics and pulmonary function, in addition to its beneficial effects on fluid balance and blood conservation. Recent investigations have suggested that removal of cytokines may be the cause of the improved cardiopulmonary function seen with MUF. METHODS: Plasma TXB2, ET-1, and LTB4 levels were measured in 34 infants undergoing CPB: 22 underwent MUF (group 1), and 12 did not (group 2). Samples were obtained at various time points. All patients underwent conventional ultrafiltration during the rewarming phase of cardiopulmonary bypass. RESULTS: In group 1, mean end-CPB TXB2 level was 101.2 pg/mL versus 46.9 pg/mL post-MUF (p < 0.05). The mean TXB2 level 1 hour post-CPB (54.1 pg/mL) was not significantly different from the post-MUF level. In group 2, the mean end-CPB TXB2 level was 123.6 pg/mL versus 53.2 pg/mL 1 hour post-CPB. Hence, TXB2 levels decreased by similar amounts and to similar levels by 1 hour post-CPB in both groups. ET-1 levels increased after CPB and were unaffected by MUF: 1.45, 1.80, 2.55 pg/mL at end-CPB, post-MUF, and 1 hour post-CPB, respectively, in group 1; and 1.51, and 2.73 pg/mL at end-CPB and 1 hour post-CPB in group 2. LTB4 levels post-MUF were 119% of pre-MUF values, and were similar at 1 hour post-CPB in both groups. CONCLUSIONS: Despite reduction in TXB2 by MUF, values were similar and approached baseline 1 hour post-CPB in both groups. LTB4 levels increased slightly with MUF. ET-1 levels increased during and post-CPB and were unaffected by MUF. MUF does not appear to have a significant effect on post-CPB levels of TXB2, ET-1, and LTB4. Therefore, the improved hemodynamics observed with MUF do not appear to be related to removal of these cytokines.

Effects of hydrotherapy on pressure ulcer healing.

Pressure ulcers are a prevalent and potentially serious medical problem encountered in both the medical and rehabilitation settings. Because the progress of rehabilitation is often interrupted by the presence of pressure ulcers, the efficient care of these wounds is of great interest to the rehabilitation team. Patients in two acute care facilities with Stage III or IV pressure ulcers were identified and consented to participate in the study contained herein. All wounds were mechanically debrided of necrotic tissue, and then the patients were randomly assigned to the conservative treatment group (A; n = 18) or the conservative treatment plus whirlpool group (B; n = 24). Conservative treatment included measures to maximize pressure relief and wound care with wet-to-wet dressings using normal saline. The dressings were changed twice daily and when they became soiled. Whirlpool was administered for 20 min per day in Group B patients. Only those patients whose ulcers were followed-up for 2 or more wk were included in the study. Ulcers were then measured by a physician who was blinded as to the treatment groups. Ulcer dimension changes over time were compared between groups. The results indicate that the conservative treatment plus whirlpool group improved at a significantly faster rate than did the conservative treatment only group (P < 0.05).

Costimulatory pathways in lymphocyte proliferation induced by the simian immunodeficiency virus SIVsmmPBj14.

The PBj14 isolate of the simian immunodeficiency virus SIVsmmPBj14 is unique among primate lentiviruses in its ability to induce lymphocyte proliferation and acutely lethal disease. The studies reported here show that viral induction of T-cell proliferation requires accessory cells, such as primary monocytes or Raji B-lymphoma cells, as well as the presence of a putative immunoreceptor tyrosine-based activation motif within the viral Nef protein. Addition of CTLA4-immunoglobulin fusion protein or anti-B7 antibodies to virally infected T cells led to substantial, but not complete, inhibition of monocyte-costimulated T-cell proliferation-suggesting that both CD28/B7-dependent and non-CD28-dependent pathways may contribute to the costimulation of virally induced lymphoproliferation. Finally, cyclosporin A, a specific inhibitor of the calcium-calmodulin-regulated phosphatase activity of calcineurin, which influences activation of the transcription factor nuclear factor of activated T cells, was shown to block virally mediated T-cell proliferation. Taken together, these findings suggest that the effect of SIVsmmPBj14 on T-cell activation may be functionally analogous, at least in part, to the effect of engagement of the T-cell receptor.

The tyrosine-17 residue of Nef in SIVsmmPBj14 is required for acute pathogenesis and contributes to replication in macrophages.

The variant simian immunodeficiency virus termed SIVsmmPBj14 induces a rapidly fatal disease in pig-tailed macaques. The acute pathogenic effects of this virus appear to be associated with at least two in vitro characteristics: the ability to induce lymphocyte proliferation; and the ability to replicate in unstimulated PBMC. Two of the amino acids in Nef of PBj14 (the No. 17 residue, tyrosine, and the No. 18 residue, glutamic acid) appear to be linked to the virus' ability to induce lymphocyte activation. To further study the effects of these amino acids on PBj14-induced pathogenesis, we generated two mutant viruses from our molecular clone, PBj6.6, containing either changes in both the No. 17 and No. 18 residues (termed PBj6.6YE-RQ), or a single change in the No. 17 residue (termed PBj6.6Y-R). In vitro analyses of these viruses showed that while their replicative abilities in stimulated peripheral blood mononuclear cells (PBMC) were altered, they still maintained the ability to replicate in unstimulated PBMC. Replication of these viruses in macrophage populations was impaired relative to the wild-type virus. Both mutant viruses were unable to induce proliferation of macaque PBMC in vitro. Virus derived from PBj6.6Y-R was unable to induce acute disease in macaques, but did maintain the ability to induce lymphopenia and intestinal lymphoid hyperplasia. These results show that the tyrosine-17 residue of Nef is linked to lymphocyte proliferation and disease development, but also suggest that the pathogenic characteristics of SIVsmmPBj14 are dependent upon multiple genetic determinants.

Development of AIDS in a chimpanzee infected with human immunodeficiency virus type 1.

The condition of a chimpanzee (C499) infected with three different isolates of human immunodeficiency virus type 1 (HIV-1) for over 10 years progressed to AIDS. Disease development in this animal was characterized by (i) a decline in CD4+ cells over the last 3 years; (ii) an increase in viral loads in plasma; (iii) the presence of a virus, termed HIV-1JC, which is cytopathic for chimpanzee peripheral blood mononuclear cells; and (iv) the presence of an opportunistic infection and blood dyscrasias. Genetic analysis of the V1-V2 region of the envelope gene of HIV-1JC showed that the virus present in C499 was significantly divergent from all inoculating viruses (> or = 16% divergent at the amino acid level) and was suggestive of a large quasispecies. Blood from C499 transfused into an uninfected chimpanzee (C455) induced a rapid and sustained CD4+-cell decline in the latter animal, concomitant with high plasma viral loads. These results show that HIV-1 can induce AIDS in chimpanzees and suggest that long-term passage of HIV-1 in chimpanzees can result in the development of a more pathogenic virus.

Deletion of the nef gene abrogates the ability of SIV smmPBj to induce acutely lethal disease in pigtail macaques.

Simian immunodeficiency virus (SIV) infection in macaque species is typically associated with the development of a progressive immunodeficiency disease, similar to human AIDS, resulting in death of animals in months to years after infection. In contrast, a variant virus, termed SIVsmmPBj, induces an acute disease in macaques, resulting in death in 5 to 14 days after infection. Previously, we have shown that several viral determinants contribute to the pathogenesis of this disease. The present study was undertaken to evaluate the role of Nef in the pathogenesis of SIVsmmPBj-induced acute disease. A molecular clone of SIVsmmPBj was generated that contains a deletion in the nef coding region (PBj6.6 delta nef). Virus derived from this molecular clone was tested with the parental virus, PBj6.6, in replication studies in pigtail macaque and rhesus macaque peripheral blood mononuclear cells (PBMCs). In general, PBj6.6 delta nef displayed markedly reduced replication abilities when compared with PBj6.6; the only exception being in stimulated pigtail macaque PBMCs, where replication kinetics were nearly identical. In addition, PBj6.6 delta nef was unable to induce the proliferation of peripheral blood mononuclear cells (PBMCs) in vitro, a unique characteristic of acutely pathogenic SIVsmmPBj. Inoculation of this virus into pigtail macaques resulted in infection, but did not result in any detectable acute disease. These studies suggest that Nef is an important viral determinant in the pathogenesis of SIVsmmPBj-induced disease, and further suggest that Nef plays a significant role in viral replication in vivo.

Viral genetic determinants in SIVsmmPBj pathogenesis.

A variant simian immunodeficiency virus (SIV) from sooty mangabeys, SIVsmmPBj, induces an acutely lethal disease in pigtailed macaques (Macaca nemestrina). This study further characterizes the viral genetic determinants involved in this acutely lethal disease. We have generated chimeric molecular clones constructed between SIVsmmPBj and either SIVsmH4 or SIVsmm9 to analyze the role of the 5' half of the genome and the envelope gene in the induction of acute disease. These studies suggest that the gag and gp40 of SIVsmmPBj are required for the development of lethal disease, and an additional determinant in the central regulatory gene region of the SIVsmmPBj genome is also required.

Effects of ionic strength on endogenous nuclease activity in chelated and nonchelated chromatin.

Calf thymus chromatin, isolated using a standard (low ionic strength, but nonchelating) isolation protocol, dialyzed against either Tris-PMSF or Tris-EDTA, was reconstituted in a high salt compacting buffer (COM) or a low salt dispersing buffer (DIS) prior to digestion with endogenous nucleases. A greater level of enzyme activity occurred when chromatin was in a condensed state (COM buffer) and not chelated prior to digestion. In contrast, chromatin chelated by dialysis against Tris-EDTA prior to digestion showed higher levels of enzyme activity in the dispersed state (DIS buffer). Nonchelated undigested chromatin contained 0.280 +/- 0.16 ug copper/mg DNA and and 0.305 +/+- 0.09 ug zinc/mg DNA. Chelation removed about 78% of copper per mg DNA and approximately 65% of zinc per mg DNA. In COM buffer after a 20 min digestion, the solubilized fraction was enriched in copper showing about 20 X more metal per mg DNA than nonchelated chromatin. Approximately the same amount of zinc was found in both chelated and nonchelated chromatin while there was less zinc in chelated chromatin solubilized in DIS buffer. Thus, chelation has important effects on the digestibility of chromatin and on the type of ionic environment that provides the most favorable conditions for endogenous nuclease activity.

5-allyl-9-oxobenzomorphans. 3. Potent narcotic antagonists and analgesics-antagonists in the series of substituted 2',9beta-dihydroxy-6,7-benzomorphans.

5-Allyl-2'-methoxy-2-methyl-9-oxo-6,7-benzomorphan methiodide (1) has been converted in a selective two-step process to the corresponding 9beta-hydroxy intermediates 4 and 6, which in turn were transformed via modified von Braun demethylation-acylation to the amides 11 and 21, respectively. These were reduced and demethylated to give a series of 5-allyl-2',9beta-dihydroxy-2-substituted 6,7-benzomorphans 13 and 23, some of which have been found to be highly potent narcotic antagonists and/or analgesics. The resolution of the most interesting compounds (23a and 23b) and pharmacological properties of the optical isomers are also described. Reduction of the double bond in 13 and 23 to give 14 and 24, with one exception, did not appreciably alter pharmacological profiles, while cyclization to the tetrahydrofuranobenzomorphans 25 substantially reduced the level of activities.