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Biomedical subjects

L M Huang

Publications and source records attributed to L M Huang.

At least 55 records · Page 3Linked to original sources
PubMed1997

Hepatitis B vaccination in preterm infants.

AIM: To investigate the immunogenicity and safety of existing recommendations for hepatitis B vaccination in preterm infants. METHODS: Recombinant hepatitis B vaccine (H-B-VAX II, 5 micrograms per dose) was given to 85 preterm infants divided into two groups, using two different schedules. Forty four group A infants with birthweights of < 2000 g received three doses at 1, 2, and 7 months of age. Forty one group B infants with birthweights of > or = 2000 g received three doses at 0, 1, and 6 months of age. RESULTS: After vaccination, 42 infants from group A (95%) and 37 infants from group B (90%) developed protective levels of antibody. The final seropositive rate and the geometric mean concentration of hepatitis B surface antibody between the two groups were not significantly different. The immune response of preterm infants to hepatitis B vaccines was similar to that of term infants in a previous study. CONCLUSIONS: Preterm infants can be given hepatitis B vaccines using one of the above two different schedules, at a cutoff birthweight of 2000 g.

Antibodies, Viral↗
PubMed1997

Helicobacter pylori acquisition in infancy after decline of maternal passive immunity.

We evaluated the natural history of Helicobacter pylori infection and the host immune response in 80 infants, and determined seroprevalence of H. pylori infection in their Taiwanese mothers. Decline in passively transferred maternal anti-H. pylori IgG antibodies and subsequent H. pylori infection was assessed in infants over 14 mo. A sensitive and specific, 96-well microtiter ELISA for the detection of H. pylori IgG antibodies was used to evaluate maternal serum (single specimen) and their infants (birth, 1, 2, 3, 6, 12, and 14 mo). Sera were also evaluated by ELISA for the presence of anti-H. pylori IgM antibodies in the infants. Maternal H. pylori IgG seroprevalence was 62.5% [50/80; 95% confidence intervals (CI), 51-73%]. All infants born to the 50 seropositive mothers passively acquired maternal H. pylori IgG. Transplacentally transferred maternal anti-H. pylori IgG lasted until about the 3rd mo of life, and disappeared in nearly all the infants by 6 mo of age. Seven and one-half percent of infants (6/80; 95% CI, 3-16%) acquired H. pylori infection; two were born to H. pylori-negative mothers. Among the six IgG seropositive infants, an IgM response specific for H. pylori antigens was detected and appeared to precede the rise in IgG in five. We conclude that maternal passive transfer of IgG antibodies occurs in the infant and disappears by 6 mo of age. H. pylori infection is acquired in infancy in this population; IgM antibodies against H. pylori are detectable, seem short-lived, and appear to precede IgG antibody development.

Antibody Formation↗
PubMed1997

Immunogenicity of Haemophilus influenzae b conjugate vaccine (HibTITER) and safety of HibTITER and a combination vaccine of diphtheria, tetanus, pertussis and HibTITER in infants two months of age: a preliminary report.

A study was undertaken to evaluate the safety and immunongenicity of a conjugate Haemophilus influenzae type b (Hib) vaccine (HibTITER) when administered concurrently with DTP (diphteria, tetanus and pertussis) vaccine in separate syringes. A total of 90 healthy children (45 per group) were randomized to receive either TETRAMUNE, a vaccine combining HibTITER with whole-cell DTP (group A), or DTP and HibTITER administered concurrently (group B) in separate syringes at approximately 2, 4 and 6 months of age in Taiwan. All children in group B achieved anti-Hib PRP (polyribosylribitol phosphate) antibody titers above 0.15 microgram/ml and 91% developed antibody titers above 1.0 microgram/ml following the third immunization. Incidences of adverse reactions were comparable between groups A and B. Besides, the incidences of adverse reactions were not significantly more frequent compared with DTP vaccination alone. We concluded that HibTITER was highly immunogenic and safe when administered concurrently with DTP vaccine to Taiwanese children. TETRAMUNE was also safe and the number of injections may be reduced in the future.

Antibodies, Bacterial↗
PubMed1997

Seroepidemiological study of measles after the 1992 nationwide MMR revaccination program in Taiwan.

The incidence of measles declined rapidly in Taiwan after the introduction of the measles vaccine into the routine immunization schedule in 1978. However, an epidemic still occurred every 3-5 years until recently. A nationwide measles-mumps-rubella (MMR) revaccination program for school and preschool children has been in place since 1992 to control the indigenous transmission of measles. In order to understand the current immune status after this recent nationwide revaccination program, we determined the presence of measles IgG antibodies by enzyme-linked immunosorbent assay (ELISA) in 1,281 blood samples from healthy persons aged from 2 months to above 30 years collected between 1993 and 1995, and also in another batch of 90 sera samples from children aged 2 years collected before 1992. The results showed that 1) the measles antibody seropositive rate (36.4%) was lowest in children aged 5-7 months and rose to an unexpectedly high level of 85.8% at the age of 12-14 months, 2) the seropositive rate rose further to between 85.9% and 95.1% after 2 years of age and remained high in adults and pregnant women, and 3) the seropositive rate of the 2-year-old children collected before 1992 was 61.4%, which was significantly lower than the rate of the same age group collected after the nationwide MMR revaccination program. We conclude that the national revaccination program has promoted effectively measles immunity in Taiwan. This immunity explains the rarity of reported measles cases since the last epidemic in 1989. This revaccination program should continue and be extended to all preschool children and young adults so that indigenous measles can be eliminated by the year 2000.

Adult↗
PubMed1997

Safety and immunogenicity of a conjugated Haemophilus influenzae type B polysaccharide-Neisseria meningitidis outer membrane protein vaccine.

This study was performed to determine the immunogenicity and safety of a conjugate Haemophilus influenzae type b (Hib) vaccine (PedvaxHIB:Merck Sharp & Dohme Inc, West Point, PA, USA) in Taiwanese children. There were two groups in this study. Group A included 56 infants at 2 months of age, who received an initial dose of Hib conjugate vaccine at age 2 months and 4 months. Another booster dose was given between 12 and 15 months of age. Group B included 58 children, aged 11 to 14 months, who were vaccinated at the time of enrollment and 2 months after the first vaccination. The results showed that this Hib conjugate vaccine was highly immunogenic with 100% and 86% of vaccinees in group A developing anti-Hib polyribosylribitol phosphate (PRP) antibody titers above 0.15 microgram/mL and 1 microgram/mL, respectively, after two vaccinations. A slightly better response rate was observed in group B, with 100% and 97% of vaccinees developing antibody titers above 0.15 microgram/mL and 1 microgram/ml, respectively, after two vaccinations. A significant booster effect was seen in group A; the proportion of subjects with antibody titers above 1 microgram/mL increased from 38% to 95%, and the geometric mean titer increased from 0.68 microgram/mL to 11.92 micrograms/mL. Adverse reactions were uncommon. Mild reactions consisted of low-grade fever and local discomfort. We conclude that the Hib conjugate vaccine is highly immunogenic and safe when given to Taiwanese children as young as 2 months of age.

Antibodies, Bacterial↗
PubMed1996

Responses to primary and a booster dose of acellular, component, and whole-cell pertussis vaccines initiated at 2 months of age.

A second generation acellular pertussis vaccine (component pertussis vaccine) containing purified pertussis toxin (PT) and filamentous hemagglutinin (FHA) was tested for its immunogenicity and safety in 2-month-old infants in comparison with first-generation acellular and whole-cell pertussis vaccines. At the ages of 2, 4, 6, and 18 months, respectively, 350 subjects were inoculated one dose of pertussis vaccine, which was combined with diphtheria and tetanus toxoids. Both acellular and component vaccines elicited significantly much fewer local and systemic reactions than whole-cell vaccine did. Besides, although not reaching statistical significance, the component vaccine was less reactogenic than the acellular vaccine. After each dose of the primary immunization, antibodies against PT and FHA were much higher in acellular and component pertussis vaccinees than in whole-cell vaccinees. However, at 18 months of age, just before the booster dose, both anti-PT and anti-FHA declined very close to, or even lower than, the prevaccination levels in all three groups and then responded rapidly to a booster dose to attain high levels. The booster responses were also significantly higher (P < 0.01) in acellular and component groups than in whole-cell group. Component and acellular vaccines induced similar levels of anti-FHA but the former induced higher anti-PT than the latter (P < 0.01). Our results indicate that both in primary immunization and as a booster, acellular and component pertussis vaccines are much more immunogenic for PT and FHA and much less reactogenic than whole-cell vaccine. However, the persistence of anti-PT and anti-FHA was not as good as one can expect from other protein antigens without giving a booster dose. A long-term follow-up of the vaccinees has been underway to understand the persistence of these antibodies after the first booster.

Antibodies, Bacterial↗
PubMed1996

The role of transplacental hepatitis B core antibody in the mother-to-infant transmission of hepatitis B virus.

AIMS/METHODS: To investigate the influence of transplacental hepatitis B core antibody (anti-HBc) on perinatal hepatitis B virus (HBV) transmission, we studied the anti-HBc titers in 294 mother-neonate pairs. RESULTS: The anti-HBc titer was highest (10(5.13 +/- 0.80) to 10(4.36 +/- 0.97) in mothers, 10(5.13 +/- 0.76) to 10(5.52 +/- 0.98) in infants) in the 200 hepatitis B e antigen (HBeAg) positive hepatitis B surface antigen (HBsAg) carrier mothers and their infants, second highest (10(4.51 +/- 0.76) and 10(4.68 +/- 0.76)) in the 60 HBeAg-negative HBsAg carrier mothers and their infants, and lowest (10(3.11 +/- 0.76) and 10(3.24 +/- 0.83)) in the 34 non-carrier mothers and their infants (p < 0.05). One hundred and ninety-two infants of HBeAg-positive carrier mothers received hepatitis B immunoglobulin as well as hepatitis B vaccines, and were followed prospectively from birth. Ten infants became HBsAg carriers, and their mothers had significantly lower anti-HBc titers than those of the mothers of 182 infants who did not become carriers (p = 0.003), while maternal serum hepatitis B virus DNA levels (29.9 +/- 23.6 versus 39.9 +/- 58.1 pg/10 ml) did not differ in those two groups (p > 0.25). The same trend was observed in the infants' anti-HBc titers in those two groups (p = 0.0006). CONCLUSIONS: The association of lower anti-HBc titers in HBeAg-positive carrier mother-infant pairs and the development of carrier status in the infants suggests a positive role of anti-HBc in the modulation of mother-to-infant transmission of HBV. A high maternal anti-HBc level in serum may be a negative predictor of immunoprophylaxis failure in high-risk infants.

Child↗
PubMed1996

Detection and sequence analysis of a new herpesvirus-like agent in AIDS and non-AIDS Kaposi's sarcoma in Taiwan.

A new herpesvirus-like DNA sequence (KSHV) has been recently identified in Kaposi's sarcoma from acquired immunodeficiency syndrome (AIDS) and non-AIDS patients. In order to verify the role of this new viral agent in Taiwan, a series of Kaposi's sarcoma specimens obtained from AIDS and non-AIDS patients in three medical centers representing different geographic locations of Taiwan were surveyed. A total of seven specimens from AIDS patients and 22 specimens from non-AIDS patients were tested for the presence of this herpesvirus-like agent by polymerase chain reaction (PCR) using the published Kaposi's sarcoma 330-233 primers. The tumor DNA was also tested for cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpes-virus type 6 (HHV-6). The Kaposi's sarcoma specimens from AIDS and non-AIDS patients were positive for KSHV except in one case. Only occasional specimens were positive for CMV and EBV, with a slightly higher positive rate for HHV-6 in AIDS and non-AIDS patients. Cloning and sequence analysis of the PCR products from two cases of Kaposi's sarcoma (one each for AIDS and non-AIDS) revealed only minor differences in this DNA sequence, as compared with the published data from north America. These results further support the assumption that this new KSHV is strongly associated with Kaposi's sarcoma in AIDS and non-AIDS patients in Taiwan.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Influenza B virus infection associated with shock in a two-month-old infant.

Influenza B virus usually causes a mild and self-limiting illness. A 2-month-old infant presented with acute symptoms suggestive of septic shock but recovered after vigorous resuscitation 1 day later. Influenza B was isolated from a throat swab taken from the infant. Bacterial cultures of blood, urine and spinal fluid had no growth. This case illustrates that the clinical signs and symptoms of influenza in infants may be indistinguishable from bacterial sepsis.

Humans↗
PubMed1995

A follow-up study of combined vaccination with plasma-derived and recombinant hepatitis B vaccines in infants.

This study was aimed to evaluate the efficacy and immunogenicity of combined hepatitis B vaccination with plasma-derived vaccine (PDV) and recombinant vaccine (RV). A total of 329 infants was recruited, including 224 high-risk infants born to hepatitis B e antigen-positive mothers and 105 low-risk infants born to hepatitis B e antigen-negative mothers. The high-risk infants received four doses of hepatitis B vaccine at 0, 1, 2 and 12 months of age with five different schedules. Group A1 and A2 infants were vaccinated with PDV as the first dose and RV (SB vaccine for group A1, MSD vaccine for group A2) as the remaining three doses. Group B1 and group B2 infants were vaccinated with PDV as the first two doses and RV (SB vaccine for group B1, MSD vaccine for group B2) as the remaining two doses. Group C infants received four doses of PDV. Low-risk infants were vaccinated with PDV at birth, and RV at 1 and 6 months of age (group D1, using SB vaccine; group D2, using MSD vaccine). At completion of vaccination schedules, 20 of 224 high-risk infants (9%) were positive for hepatitis B surface antigen. The overall protective efficacy was 90%. Hepatitis B surface antibody (anti-HBs)-positive rate ranged between 94 and 100% among the remaining infants. The protective efficacy and immunogenicity were similar among groups except that the mean level of anti-HBs in group C, D1 and D2 infants tended to be lower than that of the other four groups. To ensure an optimal immune response, four doses of vaccine are recommended in high-risk infants when two types of vaccine are to be used in combination.

Child, Preschool↗
PubMed1995

Long-term efficacy of recombinant hepatitis B vaccine and risk of natural infection in infants born to mothers with hepatitis B e antigen.

To evaluate the long-term protection afforded by the vaccine, recombinant hepatitis B (HB) vaccine was given to 171 infants born to hepatitis B e antigen-positive carrier mothers. Group A (53 infants) and group B (57 infants) received four doses of HB vaccine at birth and at 1, 2, and 12 months of age, with a dose of 20 micrograms in group A and 10 micrograms in group B. Group C (61 infants) received three 20 micrograms doses of HB vaccine at birth and at 1 and 6 months of age. These children were followed up annually up to 5 years of age. Six children (4%) became HB carriers before 1 year of age, and the carrier state persisted to the end of follow-up. The overall seropositive rate of HB surface antibody (anti-HBs) dropped from 99% at 1 year of age to 83% at 5 years of age. Among 548 serum pairs taken at 1-year intervals from children negative for HB surface antigen (HBsAg), a fourfold rise of anti-HBs titer was noted in 58 (11%) and a 10-fold rise of anti-HBs was noted in 17 (3%). Maternal HB core antibody disappeared in most children (151/152, 99%) before 2 years of age. Natural infections, as judged by persistence or reappearance of HB core antibody, occurred in 19 of 163 (12%) HBsAg-negative children. None of these episodes was associated with HBsAg positivity. We conclude that the long-term protection afforded by recombinant HB vaccine is satisfactory and that a further booster dose before 5 years of age is not necessary.

Biomarkers↗
PubMed1995

Local massage after vaccination enhances the immunogenicity of diphtheria-tetanus-pertussis vaccine.

The effect of local massage on adverse reactions and immunogenicity of diphtheria-tetanus-pertussis vaccine was investigated. After diphtheria-tetanus-pertussis vaccination 327 infants were either massaged or not, and adverse reactions were evaluated. Local pain and fever were more frequent in the massage group. The extra febrile episodes from massage were mild (38-39 degrees C). For evaluation of the antibody responses, 124 infants were recruited into massage or nonmassage cohorts and antibody production was measured at 2, 6, 7, 18 and 19 months of age, respectively. Subjects in the massage group developed significantly higher antibodies against filamentous hemagglutinin at 6 and 7 months of age, pertussis toxin at 6, 7, 18 and 19 months of age, pertussis agglutinogen at 18 and 19 months of age and those in the nonmassage group. Local massage after diphtheria-tetanus-pertussis vaccination was associated with better immunogenicity and more adverse reactions, including low grade fever and local pain, which were mild and not particularly disturbing.

Antibodies, Bacterial↗
PubMed1995

Immunomodulation treatment for childhood virus-associated haemophagocytic lymphohistiocytosis.

The Epstein-Barr virus (EBV), or human herpesvirus-6 (HHV-6) associated haemophagocytic lymphohistiocytosis, has been found prevalent in Taiwan; it affects previously healthy children and is always fatal when treated only supportively. Recognition of the underlying pathogenesis for this disease prompted adoption of an immunomodulatory regimen of intravenous immunoglobulin (IVIG) and/or etoposide on 17 such patients treated between 1990 and 1993. Remarkable improvement in patients' prognoses was demonstrated. Eight patients are still alive with a median follow-up of 1 year and 2 months post-treatment. Both IVIG and etoposide had positive immunomodulation effects such as alleviation of fever and normalization of haematological and hepatic parameters. Sustained complete response was obtained in two of nine cases of EBV-associated diseases treated with IVIG only. EBV transcripts became undetectable after etoposide and/or IVIG treatment without antiviral agents. Etoposide given by split-doses schedule appeared to be superior to conventional three-consecutive-days schedule for both remission induction and disease-free survival. Our preliminary trial apparently provides a promising improvement in the treatment of this previously fatal disease. IVIG or etoposide is effective in reversing the process of lymphohistiocytic dysregulation resulting from virus infection of immune cells in this syndrome and probably helps hosts to control active virus replication in certain cases, through immunomodulation.

Adolescent↗
PubMed1994

Human immunodeficiency viruses regulated by alternative trans-activators: genetic evidence for a novel non-transcriptional function of Tat in virion infectivity.

Thirteen genetically altered HIV-1 proviruses were created. These various genomes can be segregated into three groups: (i) a set of tat(-) viruses that have a functional HTLV-I Tax inserted in nef; (ii) a set of tat(-) viruses with Gal4 binding sites inserted in U3 and a Gal4-VP16 cDNA inserted in nef; and (iii) a set of tat(+) HIV genomes that are 5' and 3' TAR(-) and are Gal4-binding-site(+) in U3 and Gal4-VP16(+) in nef. We found that viruses in groups (i) and (ii), although tat(-), were fully complemented for viral gene expression based on quantitative measurements of viral protein synthesis and on the visualization by electron microscopy of the proper assembly of morphologically correct virions. Interestingly, group (i) and (ii) virions were defective in a spreading cytopathic infection when assayed in T-lymphocytes. Group (iii) viruses, although capable of producing intact Tat protein, also could not use Tat for transcription/gene expression because of the TAR(-) genotype. However, this class of viral genomes produced viruses that were highly infectious and cytopathic in primary and in continuously propagated T-lymphocytes. These three groups of viruses are all transcriptionally Tat-TAR independent. Their distinct differences in infectivity/cytopathicity provide genetic evidence that Tat provides a transcriptionally independent function in determining infectivity and cytopathicity in the setting of a spreading viral infection. Given that all HIV virions normally contain four intact copies of TAR RNA, our findings suggest a re-examination of whether Tat could be a virion-TAR-associated protein and the possible implications of this for virus infectivity/cytopathicity.

Base Sequence↗
PubMed1994

Response to supplementary vaccination with recombinant or plasma hepatitis B vaccine in healthy non-responding children.

Fifty-three children who failed to respond to four doses of plasma hepatitis B (HB) vaccine (anti-HBs titre < 10 IU l-1) were divided into two groups and received revaccination with either three doses of recombinant HB vaccine (10 micrograms/dose, by 0, 1, 6 month schedule; group A) or two additional doses of plasma HB vaccine (5 micrograms/dose, by 0, 1 month schedule; group B) respectively. Thirty-two vaccinees in group A had a response rate (with anti-HBs > 10 IU l-1) of 53.1% (17/32), 87.5% (28/32), and 100% (32/32) after first, second and third doses of the vaccine respectively. Twenty-one vaccinees in group B had a response rate of 61.9% (13/21) after two additional doses of plasma vaccine. High anti-HBs titres (> 1000 IU l-1) were noted in 50% of the vaccinees in group A after three doses of vaccine. Comparing anti-HBs response between group A and group B after two additional doses of HB vaccine, group A had a higher anti-HBs titre (geometric mean titre 104.7 IU l-1 versus 75.9 IU l-1) along with a better seroconversion rate (87.5 versus 61.9%). However, the differences in vaccine dose between the two groups may also be a contributory factor. Our findings indicate that three doses of recombinant HB vaccine were invariably effective in eliciting a good immune response in previous non-responders to the four doses of plasma HB vaccine. Therefore, it is speculated that these young vaccinees who did not respond to four doses of plasma HB vaccine may not be real non-responders, but hyporesponders.

Child↗
PubMed1993

Increased spacing between Sp1 and TATAA renders human immunodeficiency virus type 1 replication defective: implication for Tat function.

Expression of the human immunodeficiency virus type 1 (HIV-1) is strongly activated by Tat. The proper action of Tat requires three elements: TATAA, TAR, and upstream motifs in the HIV-1 long terminal repeat. We show here that the correct spatial arrangement among Tat, Sp1, and TATAA crucially influences HIV expression. Under conditions in which basal promoter activity is unperturbed, distancing Sp1 from TATAA markedly affected Tat trans activation. An increase in the Sp1-TATAA distance from 18 to 101 nucleotides (depending on the inserted sequence) rendered HIV-1 either partially or wholly replication defective. This critical dependence on spacing suggests that Tat-, Sp1-, and TATAA-binding factors must correctly contact each other for optimal expression and replication of HIV-1.

Base Sequence↗