Safety and immunogenicity of 3 formulations of a Sabin inactivated poliovirus vaccine produced on the PER.C6® cell line: A phase 2, double-blind, randomized, controlled study in infants vaccinated at 6, 10 and 14 weeks of age

An inactivated poliovirus vaccine candidate using Sabin strains (sIPV) grown on the PER.C6® cell line was assessed in infants after demonstrated immunogenicity and safety in adults. The study recruited 300 infants who were randomized (1:1:1:1) to receive one of 3 dose levels of sIPV or a conventional IPV based on Salk strains (cIPV). Poliovirus-neutralizing antibodies were measured before the first dose and 28 days after the third dose. Reactogenicity was assessed for 7 days and unsolicited adverse events (AEs) for 28 days after each vaccination. Serious AEs (SAEs) were recorded throughout the study. Solicited AEs were mostly mild to moderate. None of the SAEs reported in the study were judged vaccine related, including one fatal SAE due to aspiration of vomitus that occurred 26 days after the third dose of low-dose sIPV. After 3 sIPV vaccinations and across all dose levels, seroconversion (SC) rates were at least 92% against Sabin poliovirus types and at least 80% against Salk types, with a dose-response in neutralizing antibody geometric mean titers (GMTs) observed across the 3 sIPV groups. Compared to cIPV, the 3 sIPV groups displayed similar or higher SC rates and GMTs against the 3 Sabin types but showed a lower response against Salk types 1 and 2; this was most visible for Salk type 1. While the PER.C6® cell line-based sIPV showed an acceptable safety profile and immunogenicity in infants, lower seroprotection against type 1 warrants optimization of dose level and additional clinical evaluation.

Meeting report: CEPI consultation on accelerating access to novel vaccines against emerging infectious diseases for pregnant and lactating women, London, 12-13 February 2020

Infectious diseases may cause serious morbidity and mortality in pregnant women, their foetuses, and infants; the risk associated with any newly emerging infectious disease (EID) is likely unknown at the time of its emergence. While the ongoing SARS-CoV-2 pandemic shows that the development of vaccines against new pathogens can be considerably accelerated, the immunization of pregnant women generally lags behind the general population. Guided by the priority pathogen list for WHO’s R&D Blueprint for Action to Prevent Epidemics, this workshop sought to define the evidence needed for use of vaccines against EIDs in pregnant and lactating women, using Lassa fever as a model. Close to 60 maternal immunization (MI) and vaccine safety experts, regulators, vaccine developers, Lassa fever experts, and investigators from Lassa-affected countries examined the critical steps for vaccine development and immunization decisions for pregnant and lactating women. This paper reports on key themes and recommendations from the workshop.

Current practice still assumes the exclusion of pregnant women from early vaccine trials. A shift in paradigm is needed to progress towards initial inclusion of pregnant women in Phase 2 and 3 trials. Several practical avenues were delineated. Participants agreed that vaccine platforms should be assessed early for their suitability for maternal immunization. It was noted that, in some cases, nonclinical data derived from assessing a given platform using other antigens may be adequate evidence to proceed to a first clinical evaluation and that concurrence from regulators may be sought with supporting rationale. For clinical trials, essential prerequisites such as documenting the disease burden in pregnant women, study site infrastructure, capabilities, and staff experience were noted. Early and sustained communication with the local community was considered paramount in any program for the conduct of MI trials and planned vaccine introduction.

Safety and immunogenicity of a new Sabin inactivated poliovirus vaccine candidate produced on the PER.C6® cell-line: a phase 1 randomized controlled trial in adults

This first-in-human study (NCT03032588), conducted in Belgium, evaluated a new inactivated poliovirus vaccines (IPV) candidate based on Sabin poliovirus strains grown on the high-yield PER.C6® cell line. Healthy adults (N = 32) were randomized (1:1) to receive a single dose of PER.C6-based Sabin-IPV (sIPV, 15:35:112.5 DU/dose) or conventional Salk-IPV (cIPV, 40:8:32 DU/dose). Reactogenicity was assessed up to 7 days after vaccination, immunogenicity 28 days after vaccination, and safety up to 6 months after vaccination.Solicited adverse events (AEs) were mild to moderate, no changes of concern in vital signs or safety laboratory values were observed, and no severe AEs (SAEs) or vaccine-related unsolicited AEs were reported after vaccination. A trend to more frequent solicited AEs after sIPV than after cIPV administration was observed. Most participants had preexisting neutralizing antibodies against poliovirus types (titer ≥8), which were strongly boosted by sIPV. Post-vaccination geometric mean titers were high (≥12,000) and similar across the two vaccination groups. Only participants with very high preexisting antibody levels did not show a vaccine-induced response, defined in seropositive participants as a 4-fold titer increase. The 10 initially seronegative (titer <8) participants (n = 5 in each study group) seroconverted and all participants had seroprotective antibody levels post-vaccination. The antibodies elicited by sIPV neutralized both Sabin and Salk poliovirus strains.In conclusion, the PER.C6®-based sIPV was well tolerated and highly immunogenic in adults with preexisting antibodies to poliovirus.

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.

Long-term anti-HBs antibody persistence and immune memory in children and adolescents who received routine childhood hepatitis B vaccination

This paper presents data from two studies that evaluated 5-y and 10-y persistence of antibodies against hepatitis B (HBV) surface antigen (anti-HBs) and immune response to an HBV vaccine challenge in children and adolescents who had received three doses of a HBV vaccine in infancy as part of routine clinical practice [NCT00519649/NCT00984139]. Anti-HBs antibody concentrations ≥ 10 mIU/ml persisted in 83.3% (95% confidence interval [CI]: 78.5–87.5) and 78.3% (95% CI: 73.1–83.0) of subjects aged 7–8 y and 12–13 y, respectively 5–10 y after infant vaccination. One month postchallenge dose, 98.2% (95% CI: 95.9–99.4) and 93.7% (95% CI: 90.2–96.2) of subjects in the two age groups, respectively had anti-HBs antibody concentrations ≥ 100 mIU/ml. Overall, 99.6% (95% CI: 98–100) and 97.2% (95% CI: 94.5–98.8) of subjects aged 7–8 y and 12–13 y mounted an anamnestic response to the HBV challenge dose, which was well-tolerated. Healthy children aged 7–8 y and adolescents aged 12–13 y received three doses of a monovalent pediatric HBV vaccine (10 μg of HBsAg) before 18 mo of age. Serum samples collected before and one month post-HBV vaccine challenge dose were tested for anti-HBs antibody concentrations. Safety assessments were made for the HBV vaccine challenge dose. A three-dose childhood HBV immunization regimen induced persistence of antibodies against HBV infection for 10 y, up to adolescence. This vaccination regimen also conferred long-term immune memory against HBV as evidenced by the strong anamnestic response to the HBV vaccine challenge, despite waning anti-HBs antibody levels.

Antibody persistence and immune memory in healthy adults following vaccination with a two-dose inactivated hepatitis A vaccine: long-term follow-up at 15 years

Long-term persistence of vaccine-induced immune response in adults was assessed annually for 15 years following primary immunization with a two-dose inactivated hepatitis A vaccine. In 1992, 119 and 194 subjects aged 17-40 years and naïve for hepatitis A virus (HAV) were enrolled in two studies to receive 1,440 ELISA units (El.U) of inactivated hepatitis A vaccine (Havrix™, GlaxoSmithKline Biologicals, Belgium) according to a standard 0, 6 or an extended 0, 12 months schedule, respectively. Serum samples were taken 1 month after the second vaccine dose and every consecutive year up to 15 years after primary vaccination for measurement of anti-HAV antibody concentrations (NCT00291876 and NCT00289757). At year 15, 100% (48/48) and 97.3% (108/111) of subjects vaccinated at 0, 6 or 0, 12 months remained seropositive for anti-HAV antibodies, with geometric mean concentrations (GMCs) of 289.2 and 367.4 mIU/ml, respectively. An additional dose of HAV vaccine (1,440 El.U) was administered to the six subjects who had become seronegative for anti-HAV antibodies since year 11. All subjects mounted a humoral immune response to the additional HAV challenge dose, although post-challenge anti-HAV antibody levels remained low in one subject. These studies represent the longest annual follow-up of hepatitis A vaccine in healthy adults. The immune response induced by two doses of this inactivated HAV vaccine was shown to persist for at least 15 years. No difference in long-term antibody persistence was observed between the two primary vaccination schedules, reinforcing the potential for flexibility in the timing of the second primary vaccine dose.

Antibody persistence and immune memory 4 years post-vaccination with combined hepatitis A and B vaccine in adults aged over 40 years

Persistence of immune response was assessed in adults aged >40 years (N = 596) following primary vaccination with combined hepatitis A/B vaccine or concomitant monovalent hepatitis A and B vaccines. Anti-hepatitis A virus antibody responses persisted for at least 4 years regardless of the vaccine used, with anti-hepatitis B surface antibody responses higher and more sustained in subjects who received the combined hepatitis A/B vaccine. Response rates to an additional dose of the same vaccine(s) used for priming were high.

Five years follow-up following two or three doses of a hepatitis B vaccine in adolescents aged 11-15 years: a randomised controlled study

BACKGROUND

The standard three-dose schedule of hepatitis B vaccines is frequently not completed, especially in adolescents. A primary study has confirmed the equivalence of a two-dose schedule of an Adult formulation of hepatitis B vaccine [Group HBV_2D] to a three-dose schedule of a Paediatric formulation in adolescents (11-15 years) [Group HBV_3D]. This follow-up study evaluated the five year persistence of antibody response and immune memory against the hepatitis B surface (anti-HBs) antigens five years after completion of primary vaccination.

METHODS

A total of 234 subjects returned at the Year 5 time point, of which 144 subjects received a challenge dose of hepatitis B vaccine. Blood samples were collected yearly and pre- and post-challenge dose to assess anti-HBs antibody concentrations.

RESULTS

At the end of five years, 79.5% (95% confidence interval [CI]: 71.7 - 86.1) and 91.4% (95% CI: 82.3 - 96.8) of subjects who received the two-dose and three-dose schedules, respectively had anti-HBs antibody concentrations ≥ 10 mIU/mL. Post-challenge dose, all subjects had anti-HBs antibody concentration ≥ 10 mIU/mL and >94% subjects had anti-HBs antibody concentration ≥ 100 mIU/mL. All subjects mounted a rapid anamnestic response to the challenge dose. Overall, the challenge dose was well-tolerated.

CONCLUSION

The two-dose schedule of hepatitis B vaccine confers long-term immunogenicity and shows evidence of immune memory for at least five years following vaccination.

TRIAL REGISTRATION

Clinical Trials NCT00343915, NCT00524576.

Decennial administration of a reduced antigen content diphtheria and tetanus toxoids and acellular pertussis vaccine in young adults

BACKGROUND

Booster vaccination against tetanus and diphtheria at 10-year intervals is commonly recommended. Reduced antigen content diphtheria and tetanus toxoids and acellular pertussis (dTpa) vaccines developed for booster vaccination of preschool children, adolescents, and adults are licensed for once-in-a-lifetime use in most countries. Objective. To evaluate decennial administration of a dTpa vaccine. Methods. Young adults vaccinated with dTpa or diphtheria and tetanus toxoids followed by acellular pertussis (DT+ap) 1 month later in a clinical trial 10 years previously received 1 dTpa dose. Blood samples were taken before and 1 month after vaccination. Antibody concentrations against vaccine antigens were measured by enzyme-linked immunosorbent assay. Solicited and unsolicited symptoms and serious adverse events were recorded.

RESULTS

Eighty-two individuals were enrolled in the study. In the 75 individuals who had received the dTpa vaccine 10 years previously, prevaccination seroprotection or seropositivity rates were 98.8% (diphtheria), 97.5% (tetanus), 64.6% (pertussis toxoid), 100% (filamentous hemagglutinin), and 96.3% (pertactin). One month after the second booster, all study participants were seroprotected or seropositive against all vaccine antigens. Antibody concentrations increased by a similar magnitude as 10 years previously. During the 4-day follow-up, 9.9% of participants recorded grade 3 pain; 17.3% and 18.5% recorded redness and swelling of 50 mm or larger, respectively; and 8.6% recorded fever (temperature, 37.5 degrees C). No serious adverse events were considered causally related to the vaccine.

CONCLUSIONS

A second dTpa booster was highly immunogenic and well tolerated in this population of young adults. This study supports the use of this vaccine as a decennial booster.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00610168 .

A decennial booster dose of reduced antigen content diphtheria, tetanus, acellular pertussis vaccine (Boostrix™) is immunogenic and well tolerated in adults

Reduced-antigen-content diphtheria-tetanus-acellular-pertussis (dTpa) vaccines are predominantly recommended for once-in-a-lifetime use. A second dTpa (Boostrix™, GlaxoSmithKline Biologicals) administration in 164 adults previously vaccinated with dTpa 10 years previously was evaluated. Before the decennial booster, 89.4% and 94.8% subjects were seroprotected (antibodies ≥0.1 IU/mL) for diphtheria and tetanus, respectively. One-month post-booster, all subjects were seroprotected/seropositive against all vaccine antigens. Robust GMC increases indicated a booster response similar to the first booster. The decennial booster was well tolerated without serious adverse events, consistent with product experience. This study supports replacing traditional Td boosters with dTpa, and use of Boostrix™ as a decennial booster. This study is registered at www.clinicaltrials.com NCT00548171.

Primary and booster vaccination in Latin American children with a DTPw-HBV/Hib combination: a randomized controlled trial

BACKGROUND

Diphtheria-tetanus-whole-cell pertussis (DTPw)-based combination vaccines are an attractive option to rapidly achieve high coverage and protection against other important pathogens, such as hepatitis B virus (HBV) and Haemophilus influenzae type B (Hib). To ensure adequate antigen supply, GlaxoSmithKline Biologicals has introduced a new DTPw antigen source and developed a new DTPw-HBV/Hib combination vaccine containing a reduced amount of Hib polyribosylribitol phosphate (PRP). This study was undertaken to compare the immunogenicity and reactogenicity of this new DTPw-HBV/Hib vaccine with a licensed DTPw-HBV/Hib vaccine (Tritanrix™-HBV/Hib).

METHODS

This was a randomized, partially-blind, multicenter study in three countries in Latin America (Argentina, Chile and Nicaragua). Healthy children received either the new DTPw-HBV/Hib vaccine (1 of 3 lots; n = 439; double-blind) or Tritanrix™-HBV/Hib (n = 146; single-blind) co-administered with oral poliovirus vaccine (OPV) at 2, 4 and 6 months, with a booster dose at 18-24 months.

RESULTS

One month after the end of the 3-dose primary vaccination course, the new DTPw-HBV/Hib vaccine was non-inferior to Tritanrix™-HBV/Hib in terms of seroprotection/vaccine response rates for all component antigens; ≥97.3% and ≥93.9% of subjects in the two groups, respectively, had seroprotective levels of antibodies against diphtheria, tetanus, hepatitis B and Hib and a vaccine response to the pertussis component. Persistence of antibodies against all vaccine antigens was comparable between groups, with marked increases in all antibody concentrations after booster administration in both groups. Both vaccines were generally well-tolerated as primary and booster doses.

CONCLUSIONS

Results confirm the suitability of this new DTPw-HBV/Hib vaccine comprising antigens from a new source and a reduced PRP content for inclusion into routine childhood vaccination programs.

TRIAL REGISTRATION

http://www.clinicaltrials.gov NCT00332566.

The immunogenicity and safety of a reduced PRP-content DTPw-HBV/Hib vaccine when administered according to the accelerated EPI schedule

Background

Combination vaccines improve coverage, compliance and effectively introduce new antigens to mass vaccination programmes. This was a phase III, observer-blind, randomized study of GSK Biologicals diphtheria-tetanus-whole cell pertussis vaccine combined with hepatitis B and Haemophilus influenzae type b vaccines, containing a reduced amount of polyribosyl-ribitol-phosphate (PRP) and a DTPw component manufactured at a different site (DTPw-HBV/Hib_2.5 [Kft]). The primary aim of this study was to demonstrate that DTPw-HBV/Hib_2.5 [Kft] was not inferior to the licensed DTPw-HBV/Hib (Tritanrix(tm)-HepB/Hiberix(tm)) vaccine or the DTPw-HBV/Hib_2.5 vaccine, also containing a reduced amount of PRP, with respect to the immune response to the PRP antigen, when administered to healthy infants, according to the Expanded Programme for Immunization (EPI) schedule at 6, 10 and 14 weeks of age.

Methods

299 healthy infants were randomised to receive either DTPw-HBV/Hib_2.5 [Kft] DTPw-HBV/Hib_2.5 or DTPw-HBV/Hib according to the 6-10-14 week EPI schedule. Blood samples were analysed prior to the first dose of study vaccine and one month after the third vaccine dose for the analysis of immune responses. Solicited local and general symptoms such as pain, redness and swelling at the injection site and drowsiness and fever, unsolicited symptoms (defined as any additional adverse event) and serious adverse events (SAEs) were recorded up to 20 weeks of age.

Results

One month after the third vaccine dose, 100% of subjects receiving DTPw-HBV/Hib_2.5 [Kft] or DTPw-HBV/Hib and 98.8% of subjects receiving DTPw-HBV/Hib_2.5 vaccine had seroprotective levels of anti-PRP antibodies (defined as anti-PRP antibody concentration ≥0.15 μg/ml). Seroprotective antibody concentrations were attained in over 98.9% of subjects for diphtheria, tetanus and hepatitis B. The vaccine response rate to pertussis antigen was at least 97.8% in each group. Overall, the DTPw-HBV/Hib_2.5 [Kft] vaccine was well tolerated in healthy infants; no SAEs were reported in any group.

Conclusions

The DTPw-HBV/Hib_2.5 [Kft] vaccine was immunogenic and well-tolerated when administered according to the EPI schedule to Indian infants.

Trial registration

http://www.clinicaltrials.gov NCT00473668

Lasting immune memory against hepatitis B in children after primary immunization with 4 doses of DTPa-HBV-IPV/Hib in the first and 2nd year of life

BACKGROUND

Few studies have assessed long term persisting immunity against hepatitis B virus (HBV) in children vaccinated during infancy with combined vaccines containing recombinant HBV surface antigen (HBs). We assessed antibody persistence and immune memory in children 4-5 years of age, previously vaccinated with four doses of combined hexavalent DTPa-HBV-IPV/Hib vaccine (Infanrix hexa).

METHODS

Immune memory was assessed in 301 children through administration of a challenge dose of monovalent HBV vaccine.

RESULTS

At 4-5 years of age, 85.3% of subjects had persisting anti-HBs antibody concentrations >or= 10 mIU/mL, rising to 98.6% after the HBV challenge dose. All but 12 subjects (95.8%) achieved post-challenge anti-HBs concentrations >or= 100 mIU/mL. The post-challenge anti-HBs GMC rose by 100-fold compared to pre-challenge concentrations. An anamnestic response to the HBV vaccine challenge was observed in 96.8% of subjects, including 17/21 (81.0%) of children with initially undetectable antibodies (<3.3 mIU/mL). All but 4 of 42 subjects (90.5%) with anti-HBs antibodies <10 mIU/mL prior to the challenge dose, achieved seroprotective levels afterwards. A 4-fold rise in antibody concentration after the challenge dose was observed in 259/264 (98.1%) of initially seropositive subjects. The magnitude of the post-challenge responses was proportional to pre-challenge anti-HBs levels. No serious adverse events were reported during the study.

CONCLUSION

The combined DTPa-HBV-IPV/Hib vaccine induced lasting immune memory against hepatitis B. Long term protection afforded by DTPa-HBV-IPV/Hib is likely to be similar to that observed following priming with monovalent HBV vaccines.

TRIAL REGISTRATION

http://www.clinicaltrials.gov 106789 NCT00411697.

Persistence of antibodies and immune memory to hepatitis B vaccine 20 years after infant vaccination in Thailand

Booster vaccination against hepatitis B (HBV) is not currently recommended, although debate continues on the duration of protection after priming. We assessed antibody persistence and immune memory to hepatitis B 20 years after priming with a recombinant HBV-vaccine during infancy. Infants were vaccinated at birth, 1, 2 and 12 months of age. A subset received a booster dose at Year 5. Antibody persistence was measured approximately yearly until Year 20. Immune memory was assessed by administration of HBV booster dose. At Year 20, anti-HBs seroprotection rates and GMCs tended to be higher in Year 5 boosted than unboosted recipients (83.9% versus 60.5%). After the Year 20 booster dose, anti-HBs anamnestic responses were within the same range 95.8% of subjects in both groups. Primary and booster vaccination with HBV-vaccine in infants induces sustained seroprotection and immune memory against hepatitis B for up to 20 years. Higher persisting seroprotection rates in subjects boosted at Year 5 did not translate into apparent differences in immune memory in a high endemic country.

Review of 8 years of experience with Infanrix hexa (DTPa-HBV-IPV/Hib hexavalent vaccine)

Combination vaccines that include multiple antigens within one formulation are now widely accepted as an effective means of eliciting protection against several diseases at the same time. Owing to improvements in quality and convenient modes of administration, they have become part of routine pediatric practice. Hexavalent vaccines, including diphtheria, tetanus, pertussis, hepatitis B, polio and Haemophilus influenzae type b antigens represent the latest advance in the development of combination vaccines. Over 8 years since its first licensure, this review looks at the immunogenicity, efficacy and safety profile of the only hexavalent pediatric vaccine currently in use--Infanrix hexa (diphtheria, tetanus, acellular pertusis-hepatitis B virus-inactivated poliovirus vaccine/Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]; GlaxoSmithKline Biologicals, Rixensart, Belgium)--through published clinical trials and postmarketing surveillance data. These data show DTPa-HBV-IPV/Hib to be highly immunogenic and well tolerated across a range of different primary and booster vaccination schedules, as well as when administered concomitantly with other licensed vaccines (e.g., pneumococcal conjugate vaccine). Additional issues surrounding the use of hexavalent vaccines are also reviewed.

Immunogenicity and reactogenicity of DTPa-HBV-IPV/Hib vaccine as primary and booster vaccination in low-birth-weight premature infants

AIM

To assess suitability of a combined DTPa-HBV-IPV/Hib vaccine (Infanrix hexa) for immunization of low-birth-weight (<2.0 kg) preterm infants, with particular focus on the hepatitis B response.

METHODS

Open-label study in 170 preterm infants receiving primary vaccination at 2, 4 and 6 months of age and booster vaccination at 18-24 months. Enrollment and analysis were stratified in two groups: infants with birth weight between 1.5 kg and 2.0 kg (low birth weight: LBW), infants with BW <1.5 kg (very low birth weight: VLBW).

RESULTS

One month after the three dose primary vaccination, 93.7% and 94.9% of infants in VLBW and LBW groups, respectively, had anti-HBs antibody concentrations > or = 10 mIU/mL. High seroprotection and response rates (92.4-100%) to all vaccine antigens were observed. Those were reinforced (>98%) by booster vaccination for all antigens except for HBs in VLBW children: only 88.7% of those had anti-HBs antibody concentrations > or = 10 mIU/mL, compared with 96.5% of LBW children (difference statistically not significant). The vaccine was well tolerated in both groups of infants.

CONCLUSION

Preterm infants will benefit by the administration of a primary and booster vaccination with DTPa-HBV-IPV/Hib vaccine.

Neonatal vaccination with an acellular pertussis vaccine accelerates the acquisition of pertussis antibodies in infants

OBJECTIVES

Because young infants are at highest risk of pertussis complications, this study assessed whether neonatal acellular pertussis (aP) vaccination could provide earlier immunity.

STUDY DESIGN

Neonates (n = 121) were randomly assigned (1:1) to receive either aP or hepatitis B vaccine (HBV) (controls) vaccine at birth, followed by vaccination with DTaP-HBV-IPV/Hib at 2, 4 and 6 months. Immune responses were measured. Reactogenicity was assessed for 7 days after each dose.

RESULTS

The aP birth dose was followed by few adverse events. Reactogenicity of subsequent vaccine doses did not differ between groups. Seven serious adverse events were reported from each group; none were related to the study vaccines. At 3 months of age, vaccination with aP at birth had induced significantly higher antibody responses to the 3 pertussis antigens compared with controls. At 7 months, geometric mean/concentrations of antibodies against pertussis antigens were similar in both groups, and all subjects had reached "seroprotective" antibody concentrations against diphtheria, tetanus, and poliovirus types 1, 2, and 3. Geometric mean/concentrations of antibodies to haemophilus influenzae type b (Hib) and HBV were significantly lower in the aP group.

CONCLUSIONS

Early neonatal immunization with aP was safe, well tolerated, and resulted in earlier antibody responses, seen after the first dose of a DTaP combination vaccine. Birth dose of aP did not induce immunologic tolerance to pertussis antigens but appear to dampen responses to Hib and HBV vaccines.

Immunologic response to Hib tetanus toxoid conjugated vaccine coadministered with DTPa either mixed or in two separate injections in toddlers not primed with Hib vaccine

This open randomized study compared the immunogenicity and safety of a diphtheria-tetanus-acellular pertussis (DTPa) and H. influenzae polyribosylribitol phosphate conjugated to the tetanus toxoid (Hib-PRP-T) vaccine (mixed prior to administration) with separate injections of DTPa and Hib vaccines in toddlers aged two years. A total of 119 children (60 mixed; 59 separate administration), primed with DTPw, but not with Hib vaccine were enrolled. Prior to immunization only 10.3% of toddlers had anti-PRP antibody titres > or =1.0 microg/ml, compared with all children on Days 7 and 30. The anti-PRP and anti-tetanus antibody geometric mean concentrations were lower after the combined DTPa/Hib vaccine compared to separately administered vaccines (47.16 microg/ml vs 78.36 microg/ml and 24.95 IU/ml vs 40.63 IU/ml, respectively). One month after vaccination all children had anti-tetanus and anti-diphtheria antibody titres above the protective level of > or =0.1 IU/ml. The rates of recorded adverse events were similar and mostly mild or moderate in intensity whether the vaccines were combined as a single injection or given separately. We conclude that in 2-year old children, previously not immunized against Hib, a single dose of DTPa and Hib was safe and highly immunogenic irrespective of whether it was given as a combined vaccine or separate injections. Although the increase in anti-T and early (7-10 days after) anti-PRP concentrations was greater when the vaccine components were given separately than after combined administration, the DTPa/Hib combined vaccine would provide an effective method of delivering primary Hib vaccination in unprimed toddlers.

Primary vaccination of infants against hepatitis B can be completed using a combined hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliomyelitis-Haemophilus influenzae type B vaccine

INTRODUCTION

Children in Singapore receive vaccination against hepatitis B virus (HBV) at 0, 1 and 5 or 6 months of age, and vaccination against pertussis, diphtheria, tetanus, and polio at 3, 4 and 5 months of age. Parents often choose to vaccinate with the combined acellular-pertussis-inactivated polio-Hib vaccine (DTPa-IPV/Hib). We investigated whether a combined hexavalent vaccine, DTPa-HBV-IPV/Hib, could replace the separate administration of DTPa-IPV/Hib and HBV for the final vaccination at 5 months of age (Trial DTPa-HBV-IPV-075).

MATERIALS AND METHODS

In an open study, 150 children were randomised to complete their vaccination schedule with DTPa-IPV/Hib + HBV or DTPa-HBV-IPV/Hib.

RESULTS

One month after the final vaccination, there was no difference between groups in seroprotection rates or antibody concentrations against HBV. Seroprotection rates against diphtheria, tetanus, Hib and polio, as well as vaccine response rates to pertussis antigens were also similar between groups. Local and general symptoms occurred at a similar rate after the third dose of either vaccine.

CONCLUSION

The immunogenicity and reactogenicity of the hexavalent vaccine DTPa-HBV-IPV/Hib (Infanrix hexa, GSK) group is comparable to that of separately administered DTPa-IPV/Hib and HBV vaccines. Combined hexavalent vaccine, DTPa-HBV-IPV/Hib, could replace the separate administration of DTPa-IPV/Hib and HBV for vaccination at 5 months of age, thereby reducing the number of injections required.

Quality of the Haemophilus influenzae type b (Hib) antibody response induced by diphtheria-tetanus-acellular pertussis/Hib combination vaccines

It has been repeatedly observed that mixing Haemophilus influenzae type b (Hib) conjugate vaccines with acellular pertussis-containing vaccines (diphtheria-tetanus-acellular pertussis [DTPa]) resulted in a reduced magnitude of the anti-polyriboseribitolphosphate antibody response compared to that obtained when Hib vaccines were administered separately and not mixed. Nevertheless, the quality and functionality of the immune responses have been shown to be the same. With the purpose of investigating the quality of the anti-Hib immune responses that are elicited under different vaccination regimens, we report here four primary and booster-based pediatric clinical trials in which Hib vaccine was either mixed with DTPa or diphtheria-tetanus-whole-cell pertussis (DTPw)-based vaccines or was coadministered. Our results show that avidity maturation of the antibodies was lower when primary vaccination involved DTPa mixed with Hib compared to when DTPa and Hib were coadministered. No such difference was observed between mixed and separately administered Hib when associated with DTPa-hepatitis B virus-inactivated poliovirus or DTPw-based vaccines. All different combinations and regimens elicited the same opsonophagocytic and bactericidal activity as well as the same ability to protect in a passive infant rat protection assay. The functional activity of mixed DTPa-based and Hib vaccines was similar to that of mixed DTPw-based/Hib combinations. In conclusion, in vitro and in vivo data as well as postmarketing vaccine effectiveness data attest to the ability of DTPa-based/Hib combination vaccines to effectively prevent Hib-induced disease in children.

Immunogenicity and reactogenicity of primary immunization with a novel combined Haemophilus influenzae Type b and Neisseria meningitidis Serogroup C-tetanus toxoid conjugate vaccine coadministered with a Diphtheria-tetanus-acellular Pertussis-hepatitis B-inactivated poliovirus vaccine at 2, 4 and 6 months

BACKGROUND

This phase II study evaluated the immunogenicity and reactogenicity of primary vaccination with a novel Hib-MenC conjugate vaccine (GlaxoSmithKline [GSK] Biologicals) coadministered with DTPa-HBV-IPV (GSK Biologicals) at 2, 4 and 6 months.

METHODS

Healthy infants were randomized to receive Hib-MenC coadministered with DTPa-HBV-IPV (N = 117) or MenC-CRM (Wyeth) coadministered with DTPa-HBV-IPV/Hib (GSK Biologicals; N = 120) at 2, 4 and 6 months. Antibody concentrations were measured before vaccination and after doses 2 and 3. Solicited local and general symptoms, unsolicited symptoms and serious adverse events (SAEs) were recorded.

RESULTS

All subjects in the Hib-MenC group had seroprotective titers of anti-PRP antibodies (>or=0.15 microg/mL) and SBA-MenC titers (>or=1:8) 1 month after the third dose. These responses were noninferior to those seen in the control group, in which a 99.1% seroprotection rate was observed for both Hib and MenC. At that time, anti-PRP and SBA-MenC GMTs were significantly higher in the Hib-MenC group (12.8 microg/mL and 2467.1 microg/mL, respectively) than in the control group (3.8 microg/mL and 1833.7 microg/mL). High seroprotection rates were already observed after the second dose of Hib-MenC; 96.4% and 100% of subjects were seroprotected to Hib and MenC, respectively. Immune responses to coadministered antigens were unimpaired; seroprotection/vaccine response rates >or=96.5% were recorded postdose 3 in the Hib-MenC group. No differences in reactogenicity were seen between the 2 study groups.

CONCLUSIONS

Coadministration of a Hib-MenC conjugate vaccine with DTPa-HBV-IPV is well tolerated and immunogenic, and does not impair the immune response to any of the coadministered antigens.

Antibody persistence after primary vaccination with a hexavalent DTPa-HBV-IPV/HiB vaccine coadministered with a meningococcal C-CRM197 vaccine and response to a DTPa-IPV/HiB booster at 18 months of age

Children 17-20 months of age (N = 344) received a diphtheria-tetanus toxoids-acellular pertussis (DTPa)-inactivated poliovirus vaccine (IPV)/Haemophilus influenzae (Hib) booster after a 3-dose primary vaccination course with DTPa-hepatitis B vaccine-IPV/Hib plus conjugate meningococcal C vaccine-CRM. Seroprotection rates were >80% (diphtheria, tetanus, hepatitis B, polio and polyribosylribitol phosphate) before and > or =96.6% (diphtheria, tetanus, polio and polyribosylribitol phosphate) after booster vaccination. The booster was well-tolerated (fever >39.5 degrees C after <2% of doses; large swelling reactions after 6.3% of doses).

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.

Immunogenicity and reactogenicity of primary immunization with a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio-Haemophilus influenzae type B vaccine coadministered with two doses of a meningococcal C-tetanus toxoid conjugate vaccine

BACKGROUND

This study evaluated the concurrent use of meningococcal C tetanus conjugate (MenC-TT) vaccine (NeisVac-C) with DTaP-based combinations, according to 2 vaccination schedules, one of which included hepatitis B vaccination at birth (Trial DTaP-HBV-IPV/Hib-097).

METHODS

Healthy infants were randomized to receive either DTaP-HBV-IPV/Hib (Infanrix hexa) at 2, 4, and 6 months (N = 115) or HBV at birth followed by DTaP-HBV-IPV/Hib at 2 and 6 months and DTaP-IPV/Hib (Infanrix-IPV Hib) at 4 months (N = 115). In both groups 2 doses of MenC-TT conjugate were coadministered at 2 and 4 months, and compared with 3 doses of MenC-CRM197 conjugate (Meningitec) coadministered at 2, 4, and 6 months with DTaP-HBV-IPV/Hib (N = 120). Antibody concentrations were measured at 2, 6 and 7 months. Solicited local and general symptoms, unsolicited symptoms, and serious adverse events (SAEs) were recorded.

RESULTS

All MenC-TT recipients had seroprotective concentrations of anti-PRP antibodies (> or = 0.15 microg/mL) 1 month after the third vaccine dose and all had SBA-MenC titers > or = 1:8 after the second dose of MenC-TT. These responses were noninferior to those seen after 3 doses of DTaP-HBV-IPV/Hib and MenC-CRM. Anti-PRP antibody GMCs were significantly higher in MenC-TT than MenC-CRM vaccinees (7.9, 7.3, 3.8 microg/mL, respectively). Immune responses to all other coadministered antigens were unimpaired, with seroprotection/seropositivity rates > or = 98.1% in MenC-TT vaccinees. All schedules studied were well tolerated, with no differences in reactogenicity between the study groups.

CONCLUSIONS

Coadministration of DTaP-HBV-IPV/Hib or DTaP-IPV/Hib with 2 doses of MenC-TT conjugate vaccine is safe, well tolerated, and immunogenic, with no impairment of the response to the coadministered antigens.

Interchangeability of two diphtheria and tetanus toxoids, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b conjugate vaccines as a fourth dose in 15–20-month-old toddlers

BACKGROUND

Since 1998, all children in Canada have been immunized with a pentavalent diphtheria and tetanus toxoids, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b conjugate vaccine (DTaP-IPV-Hib) produced by one manufacturer (Pentacel). Recently, another DTaP-IPV-Hib (Infanrix-IPV-Hib) became available. Data on the interchangeability of these products was lacking.

METHODS

In this multicentered, observer-blind study, healthy 15-20-month-old children previously immunized with three doses of Pentacel were randomly allocated to receive a single dose of Pentacel or Infanrix-IPV-Hib. Adverse events were documented by diary for 7 days post-immunization and unsolicited adverse events were documented for 30 days.

RESULTS

433 participants were enrolled (mean age 17.1 months). Rates of fever, anorexia and irritability were similar in both groups. Injection-site redness >20 mm (11.5% versus 5.6%; p = 0.038), injection-site pain (52.1% versus 39.4%; p = 0.009) and moderate or greater drowsiness (13.8% versus 7.4%; p = 0.042) were more common after Pentacel than Infanrix-IPV-Hib. The proportions of participants who were sero-protected or who sero-responded were similar for all antigens. Geometric mean titers or concentrations were similar for antibodies against diphtheria toxoid and poliovirus type 3. Geometric mean concentrations or titers were higher in the Infanrix-IPV-Hib group against pertussis toxin (88.5 EU/mL versus 65.6 EU/mL), filamentous hemagglutinin (207.3 EU/mL versus 132.1 EU/mL), pertactin (251.9 EU/mL versus 166.9 EU/mL) and poliovirus type 1 (1293.7 versus 976.2 reciprocal dilution). Geometric mean titers or concentrations were higher in the Pentacel group against H. influenzae type b (29 microg/mL versus 19 microg/mL), tetanus toxoid (5.6 IU/mL versus 4.7 IU/mL) and poliovirus type 2 (1437.3 versus 1134.2 reciprocal dilution).

CONCLUSIONS

A booster dose of Infanrix-IPV-Hib after three priming doses of Pentacel is well-tolerated and immunogenic in 15-20-month-old toddlers and can be used interchangeably.

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.

Immunogenicity and reactogenicity of four doses of diphtheria-tetanus-three-component acellular pertussis-hepatitis B-inactivated polio virus-Haemophilus influenzae type b vaccine coadministered with 7-valent pneumococcal conjugate Vaccine

BACKGROUND

The 7-valent pneumococcal (7vPn) conjugate vaccine is licensed for primary and booster vaccination according to the same immunization schedules as routinely recommended diphtheria-tetanus-pertussis-based childhood vaccines and can be coadministered during the same vaccination visit.

METHODS

An open, randomized study evaluated the immunogenicity and safety of a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus-Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) vaccine and a 7vPn conjugate vaccine when coadministered at 2, 3 and 4 months and 12-23 months of age, compared with the administration of the hexavalent DTPa-HBV-IPV/Hib vaccine given alone. Serum antibody titers were measured before and 1 month after the primary course and before and 1 month after the booster dose. Solicited local and general adverse events were recorded for 4 days and unsolicited adverse events were recorded for 30 days after each vaccine dose.

RESULTS

A total of 345 subjects were enrolled for primary vaccination with the hexavalent vaccine (170 without and 175 with the 7vPn vaccine coadministered) and 266 returned for booster vaccination (122 without and 144 with coadministration of the 7vPn vaccine). After primary vaccination, antibody responses against the common antigens were similar in both groups, with seroprotection rates of 93.6-100% and with similar antibody decay before booster vaccination. The fourth dose induced a vigorous booster response, with seroprotection/vaccine response rates of 96.8-100%. Response to the 7vPn primary and booster vaccination was within previously reported ranges. Differences in reactogenicity resulted from higher incidences of symptoms after concomitant vaccination. Rectal temperature >39.5 degrees C was observed after 1.2% of the coadministered vaccine doses during primary vaccination and after 2.8% of the booster vaccine doses.

CONCLUSION

Coadministration of the DTPa-HBV-IPV/Hib and 7vPn vaccines at separate injection sites during the same vaccination visit was effective and safe.

Mycoplasma pneumoniae and Legionella pneumophila in community-acquired lower respiratory tract infections among hospitalized children: diagnosis by real time PCR

Mycoplasma pneumoniae and Legionella pneumophila are increasingly recognized as important agents of community-acquired lower respiratory tract infections (LRTI). Mycoplasma pneumoniae has been also recognized as a cause of nosocomial infections. The aim of this study was to investigate the role of real time polymerase chain reaction (PCR) for the rapid diagnosis of these infections among hospitalized children with community-acquired LRTI. During 2001, 65 children were prospectively studied. Microbiological investigation consisted of capillary PCR with a LightCycler for M. pneumoniae and L. pneumophila in induced sputum or throat swab specimens, IgM enzyme immunoassay for M. pneumoniae and immunofluorescence for L. pneumophila in paired sera. Serology testing showed acute M. pneumoniae infection in 18 (27.5%) patients and L. pneumophila in 1 (1.5%). M. pneumoniae was also detected in sputum specimen by capillary PCR in 9 (50%) serologically diagnosed cases, including 4 (22%) with non-diagnostic IgM levels in the acute phase. Capillary PCR and IgM enzyme immunoassay diagnosed together 15 (83%) M. pneumoniae cases in the acute phase. It is concluded that M. pneumoniae is an important cause of LRTI necessitating hospitalization among children in Greece. Capillary PCR in sputum may diagnose M. pneumoniae LRTI in the acute setting and direct therapy and isolation of patients.

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.