A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

Distinct Profiles of Consumers of Psychoactive Substances in People Attending French Sexual Transmitted Infections Centers

The objective of this cross-sectional survey was to assess the prevalence of psychoactive substance use (PSU) in people attending 11 French Sexual Transmitted Infection Centers, and to specify their profiles (PSU and link with risky sexual behaviors) using the ascending hierarchical clustering method. Among the 5220 individuals who completed the survey, 55.6% were men and the median age was 24 years [IQR: 20-31]. Among the participants, 2751 (52.7%) reported PSU at least once in their life. Ascending hierarchical clustering identified seven distinct profiles of participants based on their PSU. This study shows a high prevalence of PSU and alcohol consumption in this young population. Moreover, subgroup analysis allowed identifying groups of psychoactive substance users who presented specific risks or vulnerabilities and who should be priority targets for interventions, particularly sexual minority groups.

A comparison of booster immunisation with a combination DTPa-IPV vaccine or DTPa plus IPV in separate injections when co-administered with MMR, at age 4–6 years

This study evaluated GSK's combined DTPa-IPV vaccine (Infanrix-IPV) given as a fifth consecutive acellular pertussis booster dose in conjunction with the second dose of MMR vaccine (Priorix) in children aged 4-6 years. The immunogenicity and reactogenicity of this vaccine regimen was compared with separate injections of DTPa and IPV when given concomitantly with MMR. A cohort of 362 children previously primed with four doses of DTPa and OPV, and a single dose of MMR were randomized to receive either DTPa-IPV+MMR (N=181) or DTPa+IPV+MMR (N=181). Antibody concentrations were measured prior to and 1 month after the booster dose. After immunisation all subjects from both groups had seroprotective antibody levels against diphtheria, tetanus and the three poliovirus serotypes, > or = 96% showed vaccine response to PT, FHA and PRN, all were seropositive to mumps and rubella, and all but one subject were seropositive to measles. Immunogenicity results for each component antigen were similar for DTPa-IPV and separately co-administered DTPa and IPV. Local reactions were common with 24.0% and 31.1% of children experiencing swelling >50mm at the DTPa-IPV and DTPa injection sites, respectively. The DTPa-IPV combination did not increase the incidence or intensity of adverse events compared with separately administered DTPa+IPV. The response to the concomitantly administered MMR vaccine was similar in the two groups and similar to previously reported responses for a second dose of MMR. This combined DTPa-IPV vaccine has a similar reactogenicity profile to DTPa, is immunogenic when given as a booster dose at 4-6 years of age, and has no impact on the immunogenicity of a co-administered second dose of MMR vaccine.

Safety and immunogenicity of a combined DTPa–IPV vaccine administered as a booster from 4 years of age: A review

A combined DTPa-IPV booster vaccine was administered as a 4th or 5th dose after DTPa or DTPw priming. Over 99% vaccines developed antibody levels considered to be protective to diphtheria, tetanus and poliovirus, and >95% mounted a response to acellular pertussis antigens. Rectal temperature >39.5 degrees C was observed in at most 3.2% of vaccinees. Swelling >50 mm occurred in 24% of DTPa-primed compared to 5.5% of DTPw-primed children. Large swelling involving the entire upper arm (extending to involve the elbow joint) was reported for up to 1.2% of DTPa-primed subjects, which is consistent with literature reports for other DTPa vaccines.

Photorefractory period of the Muscovy duck (Cairina moschata): endocrine and neuroendocrine responses to day length after a full reproductive cycle

1. The Muscovy duck of equatorial origin, is photosensitive and its sexual maturation can be advanced by long days. The aim of this study was to investigate the photorefractory nature of the seasonal sexual rest in this species. 2. Sixty males were allocated to three groups of 20 birds each after completion of one full reproductive cycle in long days (16L:8D). Group A was transferred to longer days (20L:4D). Group B remained in 16L:8D. Group C was transferred to short days (6L:18D) for 9 weeks and then returned to 16L:8D. 3. Group B spontaneously redeveloped their testes and recrudescence, indicated by increased plasma concentrations of luteinising hormone and testosterone, started between the 4th and 10th week after total regression. Longer days (in group A accelerated recrudescence. Shorter days (in group C) delayed it, but the return to long days restored reproductive function. 4. In group C, the transfer to short days increased the hypothalamic content of luteinising hormone-releasing hormone. LHRH and secretion of the neuropeptide in vitro. The pituitary sensitivity to LHRH was increased in that group after the return to long days. 5. These effects show that the birds were photosensitive when daylength was changed 8 weeks after the completion of regression, and that short days were not necessary for the birds to regain photosensitivity. 6. The shortness of the regressed period and the spontaneous recrudescence in long days are more typical of equatorial birds than temperate zone species, which are more dependent on photoperiodic changes. The Muscovy duck probably retains features of its wild ancestor, which, living in equatorial latitudes, was more subject to non-photic synchronisers.

Photoperiodic control of sexual maturation in Muscovy drakes

The influence of photoperiodic control on reproductive development was investigated in Muscovy drakes by the use of night-interruption photoschedules consisting of a main photofraction of 6 hr and a secondary photofraction of 1 hr, interrupting the dark period 6 hr (Group A), 8 hr (Group B), 10 hr (Group C), and 12 hr (Group D) after dawn. Sexual maturity, assessed by the increase in plasma concentrations of luteinising hormone (LH) and testosterone, was achieved in all groups by Week 34. However, significant differences in the precocity of the rate of sexual maturation were evident on Week 27. At this time, plasma testosterone concentrations, relative to those at Week 15, had increased by 2.02, 0.29, 0.89, and 2.68 ng/ml in Groups A, B, C, and D respectively. Increases in LH concentrations followed a similar pattern. The more pronounced increases in LH and testosterone concentrations observed from Group B to Group D indicate that long days stimulate reproductive development in the Muscovy duck via a diurnal rhythm of photosensitivity. However, the nonphotostimulated increase in hormonal concentrations observed in Group A implies that a factor other than photostimulation may be involved. The dissipation of juvenile photorefractoriness by long-term short-day exposure and subsequent passive sexual maturation may explain these results. We hypothesize that the rate of sexual maturation results from a balance between the dissipation of juvenile photorefractoriness by short days and the relative strength of the photoperiodic drive as the result of long days.

Release of chicken luteinising hormone-releasing hormone-I (cLHRH-I) by mediobasal hypothalamus in the cockerel: validation of an incubation system and effect of excitatory amino acids

An in vitro system for the incubation of mediobasal hypothalami (MBH) of cockerels and a radioimmunoassay for chicken luteinising hormone-releasing hormone-I (cLHRH-I) were developed. The size of the hypothalamic fragment (MBH including the median eminence) and the incubation conditions used (40 degrees C, under constant shaking and gassing) preserved the physiological properties of the tissue. It was possible to maintain the MBH in vitro and to study the LHRH release for several hours. The assay proved sensitive enough (ED80 = 0.794 pmol/tube, ie 4.59 pg/ml) and sufficiently precise (within-assay coefficient of variation = 4.4% and between-assay coefficient of variation = 10.2%) to measure the amounts of peptide released in the incubation medium. The use of this incubation system provided the first evidence of the stimulating effect of the excitatory amino acids glutamate, NMDA and kainate on the secretion of cLHRH-I in birds. Our results suggest that the effect on the NMDA receptor is predominant.

Effect of thyroxine on testicular function, circulating luteinising hormone and pituitary sensitivity to luteinising hormone-releasing hormone in the cockerel (Gallus domesticus)

1. The effect of thyroxine (T4) on reproductive function in the adult cockerel was followed for 11 weeks. Broiler cockerels aged 96 weeks were fed on diets containing either 0, 2 or 5 mg T4/kg for 4 weeks. 2. Daily sperm output (DSO) was significantly reduced (P < 0.01) in the T4-treated groups compared with that of controls at weeks 5 and 7. In the group given 5 mg T4/kg, plasma testosterone concentration was significantly reduced (P < 0.01) compared with that in controls during the T4 treatment, in spite of the fact that there was a decrease in concentration in both control and experimental birds. Plasma luteinising hormone (LH) concentration was significantly decreased (P < 0.05) in both of the groups given T4 treatments after 3 weeks. 3. Plasma testosterone concentrations and DSO had returned to control values at weeks 5 and 11 respectively, while plasma LH showed a transient but significant (P < 0.001) rebound after removal of thyroxine from the food. 4. In contrast to other variables, the pituitary responsivity to cLHRH-I injections, was not decreased during the feeding of the T4 diet but was, on the contrary, significantly increased (P < 0.05) during treatment with 5 mg T4/kg diet, and after the end of the treatment with 2 mg T4/kg diet. 5. These results provide some evidence for an inhibitory effect of large doses of T4 on the reproductive function in the adult cockerel. Although the possibility of a direct effect of T4 on the testes cannot be excluded, T4 is likely to act, at least in part, at the hypothalamo-pituitary level, and not through a reduction in the pituitary sensitivity to LHRH.

Induced moulting in cockerels: effects on sperm production, plasma concentrations of luteinising hormone, testosterone and thyroxine, and on pituitary sensitivity to luteinising hormone-releasing hormone

1. The ability of a moult-inducing procedure to restore high levels of sperm production was assessed, in two experiments, using cockerels with reduced sperm production. The moulting procedure consisted of a period of food and light restriction for 6 weeks. The moulted birds were compared with control birds for 20 weeks. 2. Moult induction resulted in decreased daily sperm output (DSO) and plasma testosterone concentration, from weeks 3 to 7. In the first experiment, plasma luteinising hormone (LH) concentration in moulted birds was reduced on week 5. 3. No change in pituitary sensitivity to chicken luteinising hormone-releasing hormone-I (cLHRH-I) was detected at week 3 in moulted cockerels. In moulted birds, a transient increase in plasma thyroxine concentration was detected. 4. After the end of moult induction, testosterone concentrations increased, plasma LH showed a rebound at week 7 and the pituitary sensitivity to LHRH was increased at week 9. 5. This increased activity of the pituitary-testicular axis resulted for a short time in an increase in DSO of moulted birds compared with that of controls. Although amelioration was moderate, this result indicates the possibility of improving sperm production in the cockerel by using an induced moulting procedure.

A sensitive and reproducible HPLC assay for doxorubicin and pirarubicin

A high-performance liquid chromatographic method with spectrofluorometric detection has been developed for the analysis of doxorubicin (DOX), pirarubicin (PIRA) and their metabolite, doxorubicinol, in plasma. The detection was performed at 480 nm for excitation, and 590 nm for emission. The proposed technique is selective, reliable, and sensitive. The limit of quantification was 2 ng ml-1 for DOX and 5 ng ml-1 for PIRA. The reproducibility of the analytical method through statistical coefficients is approximately 5%. The accuracy of the method is good; the relative error is less than 5%.

Doxorubicin and doxorubicinol plasma concentrations and excretion in parotid saliva

The pharmacokinetics of doxorubicin (DOX) and doxorubicinol (DOXol) was studied in six patients with various advanced neoplastic diseases who received 28-72 mg/m2 DOX (nine courses). Plasma and parotid saliva were collected over a 48-h period, and DOX and DOXol were quantified by high-performance liquid chromatography with fluorescence detection. As reported previously, a wide range of plasma levels were found among our patients. It appears that in addition to being quickly cleared from the plasma, both DOX and DOXol are excreted in detectable amounts in parotid saliva, a route of elimination that has been given little attention, if any. Excretion in the saliva exposes the mucosa of the upper gastrointestinal tract to drug and may play a role in causing stomatitis in patients receiving DOX by the i.v. route. Since huge interindividual and pronounced intraindividual differences were found in S/P ratios that mostly were not systematically related to the plasma drug concentration, the concentration in parotid saliva was not useful in predicting the level of free DOX and DOXol in plasma. For the parent drug and its metabolite, the S/P ratios increased significantly with time during the 48-h period after dosing.

Bayesian estimation of doxorubicin pharmacokinetic parameters

Doxorubicin was given by brief i.v. infusion (doses ranging from 25 to 72 mg/m2) to 28 patients for 2-7 successive courses of chemotherapy (68 courses studied in all). A Bayesian approach was developed to determine the individual pharmacokinetic parameters of doxorubicin. Statistical characteristics of the population pharmacokinetic parameters were first evaluated for 19 patients and a total of 30 courses, which, when combined with 4 individual plasma concentrations of drug, led to a Bayesian estimation of individual pharmacokinetic parameters for the remaining 38 courses. The estimated parameters for the elimination phase (A3/V1 and t1/2 elimination) and the residual plasma level at 48 h as computed by Bayesian estimation on this reduced sub-optimal sampling protocol were compared with a maximal likelihood estimation of these parameters. No statistically significant differences were found. Performance of the developed methodology was evaluated by computing bias and precision. The mean errors were -0.0315 x 10(-4) l-1 for A3/V1, 0.0839 h for t1/2 elimination, and -0.22 ng/ml for c(48 h). The precision of the prediction of these three parameters (0.304 x 10(-5) l-1, 3.34 h, and 0.659 ng/ml, respectively) remained lower than the interindividual standard deviation (1.42 x 10(-4) l-1, 14.9 h, and 4.54 ng/ml, respectively). This procedure enables the estimation of individual pharmacokinetic parameters for doxorubicin at minimal cost and minimal disturbance of the patient.

Doxorubicin and doxorubicinol: intra- and inter-individual variations of pharmacokinetic parameters

Doxorubicin was given by short i.v. infusion (dose range 25-72 mg/m2) to 18 patients who underwent three to seven successive courses of chemotherapy (total, 57 courses). Plasma levels of doxorubicin and its major metabolite doxorubicinol were determined by high-performance liquid chromatography over a 48-h period after the infusion. Pharmacokinetic parameters for the parent drug and its metabolite were calculated for each course of treatment. The results show considerable inter- and intraindividual variations for most parameters. The coefficients of variation (CV) ranged from 37% to 93% (inter-individual) and from 6% to 59% (intra-individual). Nevertheless, we observed a good stability over successive courses for terminal half-life in six patients (CV, 6%-25%) and for clearance and AUC in four subjects (CV, 10%-22%). The ratio of the AUCs for doxorubicinol: doxorubicin averaged 0.514. The pharmacokinetic pattern of doxorubicinol was biphasic in plasma of the majority of patients. We propose a model for curve-fitting of these metabolite plasma concentrations that is based on two successive releases of the compound in the plasma compartment, separated by a lag time.

Long-term effects of pinealectomy on testicular function, luteinizing hormone-releasing hormone hypothalamic system, and plasma prolactin levels in the mink, a short-day breeder

Experiments in minks, as in a number of other seasonal breeders, clearly demonstrate that the pineal gland is essential for the photoperiodic control of reproduction. While maintenance of pineal-intact minks under natural photoperiods results in a set of seasonally appropriate changes in testicular activity, pinealectomized minks undergo none of these changes but rather remain sexually inactive as under long-day conditions. Thus, the consequences of pinealectomy differ from one photoperiodic species to another, but the unifying feature is the organism's need for the pineal gland to respond appropriately to changes in day length. Although the precise mechanism by which the pineal regulates hypothalamic-pituitary gonadal function remains unknown, the results of the present study indicate that, in the mink, luteinizing hormone-releasing hormone axonal transport is affected by pinealectomy. Furthermore, our results suggest that the pineal does not act exclusively upon the neuroendocrine-gonadal system but also acts on other functions that are influenced by photoperiod. Pinealectomized minks left in natural conditions cannot adjust their prolactin secretion in response to either long or short photoperiods. Operated animals continued to have plasma prolactin variations but at irregular intervals and with no apparent relation to the time of the year. The data strengthen the hypothesis that melatonin may act at some point on the hypothalamic neuroendocrine systems, which regulate the two functions differently, and that melatonin is not an anti- or progonadal substance but rather a seasonal transducer.

Circadian participation in the photoregulation of testis activity and prolactin secretion in the mink, a short-day breeder

It has been demonstrated that an endogenous mechanism is involved in photoperiodic time measurement in the mink, a short-day-breeding mannal. A study of testicular activity (testicular volume, plasma testosterone concentration) and plasma prolactin level was carried out in sexually resting minks (the experiment began in November). Groups of minks were kept in the natural photoperiod or subjected to different resonance light-dark (LD) cycles (LD 4:8, LD 4:20, LD 4:32, LD 4:44); an additional group of animals was reared in an ahemeral photoperiod (LD 4:16). A rapid increase of testicular activity was observed in control animals or those kept in LD 4:20 (T 24) and LD 4:44 (T 48). In the other groups of animals, those kept in LD 4:8 (T 12), LD 4:32 (T 36), and LD 4:16 (T 20), testicular function remained at rest. Prolactin secretion was, in contrast, stimulated in the groups kept in LD 4:8 (T 12). LD 4:32 (T 36), and LD 4:16 (T 20), and remained low in the groups kept in LD 4:20 (T 24) and LD 4:44 (T 48). These results show that the effects of the different photoperiodic regimens do not depend on the duration of the photophase, but rather on the period of the LD cycles. The LD cycles that allow an increase of testicular function are those that are inhibitory to reproduction in birds and long-day-breeding mammals. To explain these results, it is suggested that in the mink exposure to light during the circadian photosensitive phase induces inhibition of testicular activity and stimulation of prolactin secretion. To explain the opposite effects of a single photoperiod on testicular function and secretion of prolactin, the hypothesis has been advanced that, in the mink, long days might simultaneously inhibit hypothalamic luteinizing-hormone-releasing hormone (LH-RH) activity and prolactin-inhibiting factor (PIF) activity.