Drug use and its association with deviant behaviour among rural adolescent students in South Africa

OBJECTIVE

To examine prevalence of drug use in adolescent students in a rural South African community, and to measure the association between drug taking and deviant behaviour.

DESIGN

Cross-sectional survey using self-administered questionnaires.

SETTING

Seven middle and secondary schools in Moretele District, Mpumalanga Province, South Africa.

SUBJECTS

A random sample of 357 rural students comprising 193 (54.1%) females and 164 (45.9%) males, aged 11.7 to 19.9 years (mean age = 15.8; SD = 21.99).

MAIN OUTCOME MEASURES

Self-reported use of drugs. The prevalence of bullying, absenteeism and weapon-carrying among respondents who had used substances was determined.

RESULTS

Responses were obtained from 357 Grade 7-12 students. Alcohol was the most commonly used drug by the respondents. Reported lifetime prevalence of alcohol use was 47.9% (95% CI: 42.6-53.2%); tobacco, 18.2% (95% CI: 14.4-22.7%), inhalants, 5.9% (95% CI: 3.8-9.0%); cannabis 5.6% (95% CI: 3.5-8.7%). Reported use of mandrax (3.9%), tranquillizer (3.6%) and cocaine (1.4%) was low. Multivariate logistic regression analysis showed that being male (adjusted odds ratio [AOR] = 2.21; 95% confidence interval [CI]: 1.33-3.36; p = 0.002), initiating alcohol use before the age of 13 years (AOR: 2.25; 95% CI: 1.15-4.40; p = 0.018) and alcohol use were associated with absenteeism. Alcohol use, irrespective of the duration and being a male (AOR: 3.51; 95% CI: 1.50-8.20) was associated with bullying. The significant factors associated with weapon carrying were alcohol, male sex and initiating alcohol use before 13 years of age.

CONCLUSION

Drug use, particularly alcohol is common among adolescent students, especially males. There is also a positive association between drug use and undertaking precarious behaviour.

Valganciclovir is safe and effective as pre-emptive therapy for CMV infection in allogeneic hematopoietic stem cell transplantation

Despite significant advances in prevention and therapy, cytomegalovirus (CMV) infection continues to be an important cause of morbidity and mortality in the hematopoietic stem cell transplant (HSCT) recipient. The standard drug for pre-emptive therapy is intravenous ganciclovir (GCV). Valganciclovir (VGC), the oral pro-drug of GCV, has excellent bioavailability and is ideal for oral therapy. Since March 2002, VGC was adopted in our center for outpatient pre-emptive therapy in all patients undergoing allogeneic HSCT. Fifty-two allogeneic HSCT recipients were followed weekly via Digene hybrid capture assay. Patients with a positive assay were treated with VGC 900 mg p.o. b.i.d. x 14 days followed by 900 mg p.o. QD until at least 7 days after a negative test. Eighteen patients (14 sib, four MUD) had 30 episodes of CMV DNA detection treated with oral VGC. Median duration of therapy was 21 days (range 10-21 days). The rate of response was 93% (28/30) as confirmed by a negative assay within 14 days. No significant toxicity was encountered. Two patients failed oral VGC. One case of CMV enteritis was diagnosed in a patient with acute GVHD. Pre-emptive therapy of CMV infection with oral VGC is safe and effective in allogeneic HSCT recipients.

Combined modality therapy of locally advanced adenocarcinoma of the rectum: Update of a phase I trial of preoperative radiation (RT) with concurrent capecitabine (Cap) and irinotecan (Ir)

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Background: We previously reported the combination of preoperative radiation (RT) with concurrent Irinotecan and 5-FU in locally advanced rectal cancer, was well tolerated and had an excellent pathologic complete response rate (CR) of 25%, but with catheter related infections and thromboses as major toxicities (Proc Am Soc Clin Onc 22: 2003). With the potential benefits of capecitabine (Cap) and no need for an implanted catheter, a phase I study was initiated to determine the toxicity and maximum tolerated dose (MTD) of Cap with concurrent Ir and RT. Methods: Eligible patients (pts) had primary or recurrent Stage II or III rectal adenocarcinoma, without a history of prior RT or chemotherapy. The treatment regimen was as follows: external beam RT at 1.8Gy daily M-F, to a total dose of 50.4 or 54 Gy; Ir 50 mg/m2 IV, d 1, 8, 15, 22; dose escalating Cap starting at 825 mg/m2 PO divided in 2 doses, Q 12h. Surgical resection occurred at 6–10 weeks. Dose limiting toxicity is defined as Gr4 heme or non-heme Gr3. Results: A total of 16 pts have enrolled on the study, 10 male and 6 female;the median age was 57 (range 44–77). All are evaluable for toxicity. The Table reviews the maximum toxicities. Grade three diarrhea is the only dose-limiting toxicity to date. There has also been 3 pts with Gr 3 hematologic toxicity. There has been no Gr 4 toxicity. Patients are currently accruing on the 4th dose level of capecitabine. A total of 13 pts have completed the preoperative phase and three are currently on treatment. Eleven pts have had surgical resection. One pt refused surgery due to a biopsy proven CR to chemoradiation. One pt refused surgery and died of disease. Of the 11 pts undergoing surgical resection, there have been 3 pathologic CR. Conclusions: The preoperative combination of capecitabine, irinotecan and radiation in locally advanced rectal cancer pts is feasible and well tolerated. The study continues to accrue, and the MTD has not been achieved. [Table: see text]

[Table: see text]

Comparison of simian immunodeficiency virus SIVagmVer replication and CD4+ T-cell dynamics in vervet and sabaeus African green monkeys

The simian immunodeficiency viruses (SIV) naturally infect a wide range of African primates, including African green monkeys (AGM). Despite moderate to high levels of plasma viremia in naturally infected AGM, infection is not associated with immunodeficiency. We recently reported that SIVagmVer90 isolated from a naturally infected vervet AGM induced AIDS following experimental inoculation of pigtailed macaques. The goal of the present study was to evaluate the replication of this isolate in two species of AGM, sabaeus monkeys (Chlorocebus sabaeus) and vervets (C. pygerythrus). Inoculation of sabaeus AGM with SIVagmVer90 resulted in low and variable primary and set-point viremia (<10(2) to 10(4) copies/ml). In contrast, inoculation of vervet AGM with either SIVagmVer90 or blood from a naturally infected vervet (Ver1) resulted in high primary viremia and moderate plateau levels, similar to the range seen in naturally infected vervets from this cohort. CD4(+) T cells remained stable throughout infection, even in AGM with persistent high viremia. Despite the lack of measurable lymphadenopathy, infection was associated with an increased number of Ki-67(+) T cells in lymph node biopsies, consistent with an early antiviral immune response. The preferential replication of SIVagmVer in vervet versus sabaeus AGM shows that it is critical to match AGM species and SIV strains for experimental models of natural SIV infection.

Immunodeficiency in the absence of high viral load in pig-tailed macaques infected with Simian immunodeficiency virus SIVsun or SIVlhoest

Simian immunodeficiency virus (SIV) is known to result in an asymptomatic infection of its natural African monkey host. However, some SIV strains are capable of inducing AIDS-like symptoms and death upon experimental infection of Asian macaques. To further investigate the virulence of natural SIV isolates from African monkeys, pig-tailed (PT) macaques were inoculated intravenously with either of two recently discovered novel lentiviruses, SIVlhoest and SIVsun. Both viruses were apparently apathogenic in their natural hosts but caused immunodeficiency in PT macaques. Infection was characterized by a progressive loss of CD4(+) lymphocytes in the peripheral blood and lymph nodes, generalized lymphoid depletion, a wasting syndrome, and opportunistic infections, such as Mycobacterium avium or Pneumocystis carinii infections. However, unlike SIVsm/mac infection of macaques, SIVlhoest and SIVsun infections in PT macaques were not accompanied by high viral loads during the chronic disease stage. In addition, no significant correlation between the viral load at set point (12 weeks postinfection) and survival could be found. Five out of eight SIVlhoest-infected and three out of four SIVsun-infected macaques succumbed to AIDS during the first 5 years of infection. Thus, the survival of SIVsun- and SIVlhoest-infected animals was significantly longer than that of SIVagm- or SIVsm-infected macaques. All PT macaques maintained strong SIV antibody responses despite progression to SIV-induced AIDS. The development of immunodeficiency in the face of low viremia suggests that SIVlhoest and SIVsun infections of macaques may model unique aspects of the pathogenesis of human immunodeficiency virus infection in humans.

Alvimopan, a peripherally acting mu-opioid receptor antagonist, compared with placebo in postoperative ileus after major abdominal surgery

BACKGROUND

Alvimopan is a peripherally acting mu-opioid receptor (PAM-OR) antagonist for accelerating gastrointestinal recovery after surgery.

METHODS

Patients undergoing open laparotomy (bowel resection, n = 418; hysterectomy, n = 197) were randomized to receive alvimopan 6 or 12 mg or placebo orally > or = 2 h before surgery and then b.i.d. until hospital discharge (up to 7 days). The primary efficacy endpoint was time to gastrointestinal (GI) recovery (measured by toleration of solid food and passage of flatus/stool; GI-3). Secondary endpoints included time to GI-2 recovery (toleration of solid food and passage of stool) and hospital discharge order written (DCO).

RESULTS

Alvimopan did not significantly accelerate GI-3 compared with placebo [6 mg: hazard ratio (HR) = 1.20, p = 0.080; 12 mg: HR = 1.24, p = 0.038). However, after adjustment for significant covariates (sex/surgical duration), benefits were significant for both doses (6 mg: HR = 1.24, p = 0.037; 12 mg: HR = 1.26, p = 0.028). Alvimopan also significantly accelerated time to GI-2 (6 mg: HR = 1.37, p = 0.008; 12 mg: HR = 1.33, p = 0.018) and DCO (6 mg: HR = 1.31, p = 0.008; 12 mg: HR = 1.28, p = 0.015). Adverse events were similar between groups.

CONCLUSIONS

Alvimopan (6 or 12 mg) accelerates GI recovery and is well tolerated in patients undergoing open laparotomy.

Cell death, tissue hypoxia and the progression of heart failure

An important feature of heart failure is the progressive deterioration of left ventricular function that occurs in the absence of clinically apparent intercurrent adverse events. The mechanism or mechanisms responsible for this hemodynamic deterioration are not known. We and others have advanced the hypothesis that this hemodynamic deterioration results from progressive intrinsic contractile dysfunction of viable cardiomyocytes and/or from ongoing loss of cardiomyocytes. This review will focus on the concept of ongoing cardiac myocyte loss as a contributing factor to the progression of left ventricular dysfunction that characterizes the heart failure state. Specifically, the discussion will center on apoptosis or "programmed cell death" as a potential mediator of cardiomyocyte loss. In recent years, several studies have shown that constituent myocytes of failed explanted human hearts and hearts of animals with experimentally induced heart failure undergo apoptosis. Studies have also shown that cardiomyocyte apoptosis occurs following acute myocardial infarction, in the hypertrophied heart as well as in the aging heart; conditions frequently associated with the development of failure. While available data support the existence of myocyte apoptosis in the failing heart, lacking are studies which address the importance of myocyte apoptosis in the progression of LV dysfunction. As part of this discussion, we will address this issue and construct a case in support of a concept that the failing myocardium is subject to regional hypoxia, an abnormality that can potentially trigger cardiomyocyte apoptosis. If loss of cardiac myocytes through apoptosis can be shown to be an important contributor to the progression of heart failure, and if exact physiologic and molecular factors that trigger apoptosis in the heart can be identified, the stage will be set for the development of novel therapeutic modalities aimed at preventing, or at the very least retarding, the process of progressive ventricular dysfunction and the ultimate transition toward end-stage, intractable heart failure.

Plateau levels of viremia correlate with the degree of CD4+-T-cell loss in simian immunodeficiency virus SIVagm-infected pigtailed macaques: variable pathogenicity of natural SIVagm isolates

Simian immunodeficiency virus from African green monkeys (SIVagm) results in asymptomatic infection in its natural host species. The virus is not inherently apathogenic, since infection of pigtailed (PT) macaques (Macaca nemestrina) with one isolate of SIVagm results in an immunodeficiency syndrome characterized by progressive CD4+-T-cell depletion and opportunistic infections. This virus was passaged once in a PT macaque and, thus, may not be entirely reflective of the virulence of the parental strain. The goal of the present study was to assess the pathogenicity of the PT-passaged isolate (SIVagm9063) and two primary SIVagm isolates in PT macaques, including the parental strain of the PT-passaged variant. Infection of macaques with any of the three isolates resulted in high levels of primary plasma viremia by 1 week after inoculation. Viremia was quickly controlled following infection with SIVagm155; these animals have maintained CD4+-T-cell subsets and remain healthy. The plateau levels among SIVagm90- and SIVagm9063-inoculated macaques varied widely from 100 to 1 million copies/ml of plasma. Three of four animals from each of these groups progressed to AIDS. Setpoint viremia and the degree of CD4+-T-cell loss at 6 months postinfection were not significantly different between macaques inoculated with SIVagm90 and SIVagm9063. However these parameters were significantly different in SIVagm155-inoculated macaques (P values of <0.01). Considering all the macaques, the degree of CD4+-T-cell loss by 6 months postinfection correlated with the plateau levels of viremia. Thus, similar to SIVsm/mac infection of macaques and human AIDS, viral load is an excellent prognostic indicator of disease course. The inherent pathogenicity of natural SIVagm isolates varies, but such natural isolates are capable of inducing AIDS in macaques without prior macaque passage.

Highly pathogenic SHIVs and SIVs target different CD4+ T cell subsets in rhesus monkeys, explaining their divergent clinical courses

In contrast to simian immunodeficiency viruses (SIVs), which induce immunodeficiency over a 1- to 3-year period, highly pathogenic simian-human immunodeficiency viruses (SHIVs) cause a complete, irreversible, and systemic depletion of CD4(+) T lymphocytes in rhesus monkeys within weeks of infection. By using small-molecule competitors specific for CCR5 and CXCR4 in ex vivo assays, we found that highly pathogenic SHIV(DH12R) exclusively uses CXCR4 for infection of rhesus peripheral blood mononuclear cells, whereas SIV(mac239) and SIV(smE543) use CCR5 for entry into the same cells. During the period of peak virus production in SHIV(DH12R)- or SHIV(89.6P)-infected rhesus monkeys, massive elimination of CXCR4(+) naïve CD4(+) T cells occurred. In contrast, circulating CCR5(+) memory CD4(+) T cells were selectively depleted in rapidly progressing SIV-infected monkeys. At the time of their death, two SIV rapid progressors had experienced a nearly complete loss of the memory CD4(+) T cell subset from the blood and mesenteric lymph nodes. Thus, pathogenic SHIVs and SIVs target different subsets of CD4(+) T cells in vivo, with the pattern of CD4(+) T lymphocyte depletion being inextricably linked to chemokine receptor use. In the context of developing an effective prophylactic vaccine, which must potently control virus replication during the primary infection, regimens that suppress SHIVs might not protect monkeys against SIV or humans against HIV-1.

The Emergence of Selective 5-HT2B Antagonists Structures, Activities and Potential Therapeutic Applications [General Reviews]

5-HT(2) receptors mediate a large array of physiological and behavioral functions in humans via three distinct subtypes: 5-HT(2A), 5-HT(2B)and 5-HT(2C). While selective 5-HT(2A)antagonists have been known for some time, knowledge of the precise role played by the 5-HT(2B)receptor was hampered by the existence of solely 5-HT(2B)5-HT(2C) mixed antagonists. However, selective 5-HT(2B)antagonists began recently to emerge in the literature. Indeed, four structural classes belonging to the piperazine, indole, naphthylpyrimidine and tetrahydro-beta-carboline scaffolds were reported. In this paper, we will briefly review the structural and pharmacological features of selective 5-HT(2B) antagonists, including patent literature of the last five years.

Boltzmann entropy for dense fluids not in local equilibrium

Using computer simulations, we investigate the time evolution of the (Boltzmann) entropy of a dense fluid not in local equilibrium. The macrovariables M describing the system are the (empirical) particle density f=[f(x,v)] and the total energy E. We find that S(f(t),E) is a monotone increasing in time even when its kinetic part is decreasing. We argue that for isolated Hamiltonian systems monotonicity of S(M(t))=S(M(X(t))) should hold generally for "typical" (the overwhelming majority of) initial microstates (phase points) X0 belonging to the initial macrostate M0, satisfying M(X0)=M(0). This is a consequence of Liouville's theorem when M(t) evolves according to an autonomous deterministic law.

Immune failure in the absence of profound CD4+ T-lymphocyte depletion in simian immunodeficiency virus-infected rapid progressor macaques

A fraction of simian immunodeficiency virus (SIV)-infected macaques develop rapidly progressive disease in the apparent absence of detectable SIV-specific antibody responses. To characterize the immunopathogenesis of this syndrome, we studied viral load, CD4+ T-lymphocyte numbers as well as cellular and humoral immune responses to SIV and other exogenous antigens in four SIVsm-infected rhesus macaques that progressed to AIDS 9 to 16 weeks postinoculation. Each of these animals exhibited high levels of viremia but showed relatively preserved CD4 T lymphocytes in blood and lymphoid tissues at the time of death. Transient SIV-specific antibody responses and cytotoxic T-lymphocyte responses were observed at 2 to 4 weeks postinoculation. Two of the macaques that were immunized sequentially with tetanus toxoid and hepatitis A virus failed to develop antibody to either antigen. These studies show that the SIV-infected rapid progressor macaques initially mounted an appropriate but transient cellular and humoral immune response. The subsequent immune defect in these animals appeared to be global, affecting both cellular and humoral immunity to SIV as well as immune responses against unrelated antigens. The lack of CD4 depletion and loss of humoral and cellular immune responses suggest that their immune defect may be due to an early loss in T helper function.

Migrant-nonmigrant fertility differentials in Anhui, China

"This analysis is designed to provide insights into the relation between migration and fertility in China. Survey data collected from Anhui Province in 1989 are used to evaluate whether fertility is higher or lower among the temporary migrants to urban places in comparison to permanent residents in those locations.... Our analysis will...assess the extent to which socioeconomic characteristics, family planning, and migration help to explain observed differences in the fertility of temporary migrants and permanent residents. In doing so, the basic question to be answered is whether temporary migrants have used their movement as a way to avoid official policies controlling fertility and, in so doing, have they contributed to a higher than average fertility in China?"