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Biomedical subjects

M Santosham

Publications and source records attributed to M Santosham.

At least 73 records · Page 4Linked to original sources
PubMed1992

Evaluation of bacterial polysaccharide immune globulin for the treatment or prevention of Haemophilus influenzae type b and pneumococcal disease.

A human hyperimmune globulin termed bacterial polysaccharide immune globulin (BPIG) has been prepared from plasma donors immunized with Haemophilus influenzae type b (Hib), pneumococcal, and meningococcal vaccines. At a dose of 0.5 ml/kg, BPIG increased levels of antibody to Hib by greater than 0.15 microgram/ml within 4-6 h and by 2-4 micrograms/ml at 72 h. Thereafter, antibody declined, with a mean half-life of 27 days. BPIG treatment of Apache infants did not impair their active antibody responses to concurrently administered diphtheria-tetanus-pertussis or Hib oligosaccharide-diptheria CRM197 conjugate vaccines. In high-risk Apache infants, BPIG given at 2, 6, and 10 months of age provided significant protection from invasive Hib infection during infancy. Thus, BPIG may have utility in the prevention of Hib infections in high-risk patients who cannot be immunized adequately with Hib conjugate vaccines.

Antibodies, Bacterial↗
PubMed1992

Prevention of Haemophilus influenzae type b infections in Apache and Navajo children.

Prospective surveillance of Haemophilus influenzae type b (Hib) disease has been done since 1981 in two high-risk populations, White Mountain Apaches and Navajos. The attack rate in children less than 5 years of age is 5-10 times higher than in the general US population. Three vaccines were evaluated. Unconjugated Hib capsular polysaccharide produced lower antibody responses in 18- and 24-month-old Apache infants than in white infants. HbOC (Hib oligosaccharide covalently linked to the nontoxic mutant diphtheria toxin CRM197) produced low antibody responses in Navajo infants after one or two doses but induced responses similar to those in whites after three doses. The responses of 18-month-old Navajos to HbOC were lower than those of whites, but most achieved protective levels. PRP-OMP (Hib capsular polysaccharide linked to the outer membrane protein complex of Neisseria meningitidis) produced good immune responses in 2-month-old Navajo and Apache infants after a single dose. This vaccine was greater than 90% efficacious in protecting Navajo infants from Hib disease when given at 2 and 4 months of age. Even a single dose achieved a high protective efficacy.

Antibodies, Bacterial↗
PubMed1992

Persistent urinary antigen excretion in infants vaccinated with Haemophilus influenzae type b capsular polysaccharide conjugated with outer membrane protein from Neisseria meningitidis.

Testing for urinary excretion of capsular polysaccharide antigen was carried out in 40 four-month-old Navajo infants who had received injections of a Haemophilus influenzae type b Neisseria meningitidis outer membrane protein conjugate vaccine (PedvaxHIB; Merck, Sharp and Dohme Research Laboratories) as part of an ongoing efficacy trial of the vaccine. Urine from 12 placebo recipients was also analyzed. Urine samples were collected on the day of injection (the first voided urine following the injection) and 3, 7, 10, 14, 21 and 30 days later. All vaccine recipients had at least 1 positive specimen. Vaccine recipients excreted antigen for a median period of 14 days after injection. On the first day 54% of vaccinees excreted antigen. Antigen was excreted by 89% of vaccinees on Day 3, 79% on Day 7, 82% on Day 10, 64% on Day 14, 56% on Day 21 and 41% on Day 30. Urine from placebo recipients tested positive in 12% on Day 1, 18% on Day 3, none on Day 7, 14% on Day 10, 11% on Day 14, 10% on Day 21 and none on Day 30. The rate of positive test results was significantly higher among vaccine recipients than among controls. Physicians should not rely on urinary antigen detection tests for predicting the presence of invasive disease caused by H. influenzae type b in infants for at least 30 days after injections with this conjugate vaccine, and possibly longer.

Antigens, Bacterial↗
PubMed1992

Children with Haemophilus influenzae bacteremia initially treated as outpatients: outcome in 85 American Indian children.

Eighty-five American Indian children less than 16 years of age with Haemophilus influenzae bacteremia were retrospectively determined to have been treated as outpatients after their initial evaluation. We hoped to determine the proportion that developed new foci, the time interval to this development and whether age or temperature at presentation predicted outcome. Fifty-one (60%) presented with nonfocal findings. Seventy-two (85%) were treated with antibiotics at the initial visit. Although 49 (58%) of the patients were never hospitalized, a new focus was identified in 25 (29%), including 13 (15%) with a final diagnosis of meningitis. The new foci were identified within 6 days of presentation (median, 2 days). An additional 15 (18%) patients had no new focus but were febrile and/or ill at follow-up. All patients with meningitis or a second positive culture were hospitalized at the first follow-up visit. Age and temperature at presentation did not help predict outcome. All patients with H. influenzae bacteremia require prompt reevaluation and close follow-up by an experienced physician.

Ambulatory Care↗
PubMed1992

Distribution of serotypes of human rotavirus in different populations.

Serotyping is a useful tool to study the epidemiologic characteristics of rotaviruses in large populations and to assess the need for a vaccine to protect against all strains. By using an enzyme immunoassay with serotype-specific monoclonal antibodies to the four most common rotavirus serotypes, we analyzed 1,183 rotavirus-positive specimens from 16 stool collections in eight countries on four continents that were obtained from 1978 to 1989. Of the 926 strains (78%) that could be serotyped, 48% were serotype 1, 8% were serotype 2, 15% were serotype 3, and 7% were serotype 4. Twenty-two percent had insufficient numbers of double-shelled virus particles to react with the monoclonal antibody of the VP4 rotavirus protein and therefore could not be serotyped. Our results indicate that vaccines being developed must provide the greatest coverage against serotype 1 and that the serotype distribution cannot be predicted currently by the geographic area or prevalence in the preceding year.

Antibodies, Monoclonal↗
PubMed1992

High incidence rates of invasive pneumococcal disease in the White Mountain Apache population.

OBJECTIVE: In this article we determine the incidence and clinical spectrum of invasive pneumococcal disease in the White Mountain Apache population, a group known to have a high incidence of invasive disease due to Haemophilus influenzae type b. DESIGN: Patients from whom cultures of normally sterile body sites yielded Streptococcus pneumoniae were identified retrospectively through review of hospital laboratory records from a 6.8-year period. Clinical data were reviewed and incidence rates were computed. SETTING: The Whiteriver Indian Health Service Hospital is located on the 1.7-million-acre White Mountain Apache Reservation in eastern Arizona. PATIENTS: Approximately 10,000 members of the White Mountain Apache Tribe reside on or near the reservation and receive health care through the Whiteriver Indian Health Service Hospital. OUTCOME MEASURES: The average annual incidence rates of invasive pneumococcal disease were calculated and clinical characteristics were reviewed. RESULTS: One hundred thirty-eight cases of invasive pneumococcal disease were identified. The average annual incidence rate was 207 per 100,000 population, and 156 per 100,000 population when adjusted for age by direct standardization to the 1988 US population. The incidence rate was highest in children between 1 and 2 years--2396 per 100,000. The overall case-fatality rate was 5%. Pneumococcal pneumonia was the diagnosis in 79% of the patients 5 years of age or older. Alcohol abuse, identified in 66% of the cases in adults, was the most common underlying medical condition. CONCLUSION: The incidence rates in White Mountain Apaches are the highest reported for any population. A vaccine effective in children would greatly benefit this population.

Adolescent↗
PubMed1992

Enterotoxigenic Bacteroides fragilis: epidemiologic studies of its role as a human diarrhoeal pathogen.

Strains of Bacteroides fragilis which produce enterotoxin(s) (ETBF) have been associated with diarrhoeal diseases in young domestic animals and have also been isolated from humans with diarrhoea. We have determined epidemiologically that ETBF are significantly associated with diarrhoea in humans. We studied Apaches, primarily children, with diarrhoea attending an outpatient facility in Whiteriver, Arizona, from July 1986 through July, 1988. Stool cultures for isolation of ETBF and other diarrhoeal pathogens were taken from these persons as well as from age and time-matched control persons who did not have diarrhoea. ETBF were isolated significantly more often from persons with diarrhoea (12%) than from controls (6%), p = 0.03. Isolation was highest (20-24% of stool cultures positive) during the second and third years of life. The diarrhoeal syndrome associated with ETBF was non-specific, and most characteristic of a secretory, rather than inflammatory, type of diarrhoea. ETBF are significantly associated with acute diarrhoea in Apache children, and may be an important newly described cause of diarrhoea in humans.

Acute Disease↗
PubMed1991

The efficacy in Navajo infants of a conjugate vaccine consisting of Haemophilus influenzae type b polysaccharide and Neisseria meningitidis outer-membrane protein complex.

BACKGROUND AND METHODS: Several conjugate vaccines against Haemophilus influenzae type b have been developed in the search for one that induces protection even in young infants. We evaluated the safety and efficacy of a conjugate vaccine that links the H. influenzae type b capsular polysaccharide to the outer-membrane protein complex (OMPC) of Neisseria meningitidis serogroup B. We conducted a double-blind, placebo, controlled trial in Navajo infants, who are at high risk for systemic infections caused by H. influenzae type b. The infants were randomly assigned to receive the first dose of vaccine or placebo at 42 to 90 days of age and the second at 70 to 146 days of age. RESULTS: Of the infants in the trial, 2588 were assigned to receive the vaccine and 2602 to receive placebo. The mean follow-up was 269 days in the vaccine group and 267 days in the placebo group. Before the age of 18 months, there was 1 systemic H. influenzae type b infection in the vaccine group, as compared with 22 in the placebo group (P less than 0.001; point estimate of efficacy, 95 percent; 95 percent confidence interval, 72 to 99 percent). Of the 22 H. influenzae type b infections in the placebo group, 13 were meningitis. Among the children who received both doses, there was 1 H. influenzae type b infection in the vaccine group (n = 2056) and 14 in the placebo group (n = 2105) (P less than 0.001; point estimate of efficacy, 93 percent; 95 percent confidence interval, 53 to 98 percent). The single infection in the vaccine group occurred at 15 1/2 months of age in an infant with osteomyelitis. Between the first and second doses there were no H. influenzae type b infections in the vaccine group and eight in the placebo group (P less than 0.005; point estimate of efficacy, 100 percent; 95 percent confidence interval, 41 to 100 percent). CONCLUSIONS: The H. influenzae type b OMPC vaccine, administered at 2 and 4 months of age, is safe and induces a high rate of protection against invasive disease caused by H. influenzae type b in infants under the age of 18 months. Protection begins after the first dose.

Antibody Formation↗
PubMed1991

A field study of the safety and efficacy of two candidate rotavirus vaccines in a Native American population.

A double-blind, randomized, placebo-controlled trial was conducted to evaluate the safety and efficacy of a rhesus rotavirus vaccine and RIT 4237, a bovine rotavirus vaccine, in a Navajo population. Infants aged 2-5 months were randomized to receive one dose of either 10(4) pfu of the rhesus rotavirus vaccine or 10(8) pfu of the RIT 4237 vaccine or placebo. Eleven (10.2%) of 108 infants in the rhesus vaccine group, 11 (10.4%) of 106 in the RIT 4237 group, and 9 (8.4%) of 107 in the placebo group experienced rotavirus diarrhea during the follow-up period of 17 months. Thus, in this population, neither vaccine was efficacious in preventing rotavirus diarrhea.

Diarrhea, Infantile↗
PubMed1991

Safety and immunogenicity of a Haemophilus influenzae type b conjugate vaccine in a high risk American Indian population.

The safety and immunogenicity of a Haemophilus influenzae type b polysaccharide conjugate vaccine linked to the outer membrane protein complex of Neisseria meningitidis (Hib-OMP) were evaluated among Apache and Navajo infants and children. One dose of the Hib-OMP was given to 42 children who were from 12 and 60 months of age. Ninety-two infants 6 to 8 weeks old were given one dose of Hib-OMP at the time of enrollment. A subsequent dose of the vaccine was given 2 months later and a third dose was offered between 12 and 15 months of age. All of the 12- to 60-month-old children achieved a protective antibody concentration (greater than 1 microgram/ml) 1 month postvaccination. Among the 6- to 8-week-old infants only 11% of the Apaches and 8% of Navajos had a protective anti-PRP antibody concentration prevaccination. One month post vaccination 68% of the Apaches and 69% of the Navajos had protective anti-PRP antibody concentrations. One month after the second immunization 67% of the Apaches and 75% of Navajos had protective anti-PRP concentrations. Among the infants that received the third (booster) immunization (N = 28) 74% had protective anti-PRP antibody titers just before the booster immunization. One month after the booster immunization all of the infants had protective concentrations of anti-PRP antibody. We conclude that the Hib-OMP is safe and highly immunogenic among Apache and Navajo infants and children.

Antibodies, Bacterial↗
PubMed1991

Role of a soy-based lactose-free formula in the outpatient management of diarrhea.

The introduction of a soy-based, lactose-free formula during the acute phase of diarrheal illness in infants has been shown to reduce stool output and duration of diarrhea in hospitalized patients. In the United States, most infants with acute diarrhea are treated as outpatients. In the present study, infants with diarrhea who were treated as outpatients were randomly assigned to receive either a soy-based, lactose-free formula alternating with oral rehydration solution from the beginning of therapy ("early feeding") or oral rehydration solution alone for the first 24 hours of therapy, followed by a soy-based, lactose-free formula alternating with oral rehydration solution (control group). Twenty-nine infants were randomly assigned to the early-feeding group and 27 to the control group. Twenty-one (72%) of 29 in the early-feeding group resolved their diarrhea at the end of 48 hours of therapy compared with 12 (44%) of 27 in the group fed oral rehydration solution only (P = .02). It is concluded that the introduction of a soy-based, lactose-free formula from the beginning of therapy for acute diarrhea in children treated as outpatients is safe and may shorten duration of diarrhea while maintaining adequate caloric intake.

Ambulatory Care↗
PubMed1990

Impaired antibody response to Haemophilus influenzae type b polysaccharide and low IgG2 and IgG4 concentrations in Apache children.

BACKGROUND AND METHODS: Because Native American children are at much higher risk for invasive Haemophilus influenzae type b infection than white children, we compared the antibody responses to H. influenzae type b polysaccharide vaccine in healthy Apache and white children. RESULTS: The concentrations of H. influenzae type b antibody after immunization with polysaccharide vaccine were approximately 10-fold lower in 24-month-old Apache children than in whites of a similar age (P less than 0.01). The decreased response involved H. influenzae type b antibodies of the IgG, IgM, and IgA classes. Concentrations of IgG antibody to tetanus toxoid did not differ significantly, and IgG antibodies to diphtheria toxoid were only twofold lower (P = 0.028). Although total IgG, IgM, and IgA levels were higher in two-year-old Apaches than in whites (all P less than 0.001), IgG2 and IgG4 subclasses were lower (both P less than 0.001). Among the Apaches, individual immunoglobulin levels and allotypes were not significantly correlated with their antibody responses to H. influenzae type b polysaccharide. CONCLUSIONS: Apache children have significant impairment of their antibody response to H. influenzae type b polysaccharide and little or no impairment of their antibody responses to protein toxoids. This immunodeficiency may explain the high incidence of H. influenzae type b infection in this population.

Antibodies, Bacterial↗
PubMed1990

A comparison of rice-based oral rehydration solution and "early feeding" for the treatment of acute diarrhea in infants.

To compare the use of rice-based oral rehydration solution (R-ORS), with the introduction of food immediately after rehydration ("early feeding"), using standard glucose-based oral rehydration solution (G-ORS) in the management of acute diarrhea, we conducted a four-cell randomized, controlled trial among 200 hospitalized Egyptian infants between 3 and 18 months of age. During the rehydration phase (first 4 hours), three groups were given G-ORS and a fourth group was given R-ORS. During the subsequent maintenance phase, the control group was given a soy-based, lactose-free formula (G-ORS + SF), a second group (G-ORS + RF) was given a rice-based formula, and a third group (G-ORS + rice) was given boiled rice. The fourth group (R-ORS + SF) continued to receive R-ORS for the first 24 hours of the maintenance period, followed by a soy-based lactose-free formula. During the first and second 24 hours of the maintenance period, infants in the three treatment groups had a lower mean stool output in comparison with the control group (p = 0.006 and 0.03, respectively). The mean total stool output in the R-ORS + SF group was significantly lower than in the control group (p = 0.02). There were no statistically significant differences among the four groups in the mean duration of diarrhea. We conclude that (1) infants who were given R-ORS had reduced total stool output (by 35%) compared with the control group and (2) feeding of boiled rice or a rice-based formula immediately after rehydration therapy was as efficacious as treatment with R-ORS alone for 24 hours, followed by feeding with a soy-based, lactose-free formula.

Acute Disease↗
PubMed1990

Rotavirus diarrhoea in Apache children: a case-control study.

A case-control study of rotavirus diarrhoea in Apache children up to two years old was conducted at the White Mountain Apache reservation from 1 May through 15 December 1985 to identify risk factors for rotavirus diarrhoea. The mothers of fifty cases, forty-five hospital controls and twenty-five neighbourhood controls participated in this study. Exposure to other children with diarrhoea stood out as the single most important factor for acquiring rotavirus diarrhoea (Odds ratio = 14.0). Other significant risk factors were living in homes with septic tanks and in homes with 'poor environmental sanitation.'. Minimizing contacts of children with diarrhoea therefore would be the most effective measure in preventing the spread of this disease in the community.

Arizona↗
PubMed1990

Passive immunization for infection with Haemophilus influenzae type b.

Haemophilus influenzae type b is the leading cause of meningitis in children younger than 5 years of age in the United States. The incidence of infection with H influenzae type b in certain populations, such as Apache and Navajo Indians and Alaskan Eskimos, is 10 to 20 times higher than in the general US population. Another important feature of H influenzae type b infections in these populations is that more than 80% of the cases occur during the first year of life, with 35% to 45% occurring during the first 6 months. One of the currently licensed vaccines that contains the capsular polysaccharide of the H influenzae type b organism is not reliably immunogenic in infants younger than 18 months of age. A number of new H influenzae type b vaccines prepared by covalently coupling the H influenzae type b capsular polysaccharide with a protein carrier antigen are undergoing clinical evaluation. One of these conjugate vaccines was shown to be efficacious in preventing disease caused by H influenzae type b in Finnish infants when they were immunized at 3, 4, and 6 months of age. Unfortunately, in a recently concluded trial, the same vaccine was not found to be efficacious in preventing such disease in infants younger than 1 year of age among the Alaskan Eskimo population. We have evaluated an alternative approach for protecting high-risk infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1989

Infantile gastroenteritis associated with excretion of pestivirus antigens.

Faeces from children under 2 years old who had gastroenteritis that could not be attributed to recognised enteric pathogens were examined with a monoclonal-antibody-based immunoassay for Pestivirus antigens. Such antigens were detected in 30 of 128 episodes of gastroenteritis. Children without diarrhoeal disease and children infected with rotaviruses had little evidence of Pestivirus infection (faeces positive in 1 of 28 and 1 of 31, respectively). The diarrhoeal disease in children excreting Pestivirus antigens resembled that in other children except that it was more commonly associated with signs and symptoms of respiratory inflammation.

Antibodies, Monoclonal↗
PubMed1988

Comparison of active and combined passive/active immunization of Navajo children against Haemophilus influenzae type b.

In a high risk Navajo population we compared the immunogenicity of a new Haemophilus influenzae type b mutant-diphtheria toxic conjugate vaccine (HbOC) with simultaneous active (HbOC) and passive immunization with bacterial polysaccharide immunoglobulin prepared from adults immunized with H. influenzae b, pneumococcal and meningococcal vaccines. Only 7 of 26 (27%) 2-month-olds had an increase in H. influenzae b capsular polysaccharide antibody after a single dose of HbOC, a proportion similar to that of saline controls (9 of 25, 36%). After a second HbOC dose at 4 months 88% had antibody concentrations of 0.15 microgram or more, and after a third dose at 6 months all had antibody levels greater than or equal to 0.15 microgram/ml. The group receiving both HbOC and bacterial polysaccharide immunoglobulin at 2 months uniformly had H. influenzae b CP antibody concentrations of greater than or equal to 0.15 microgram/ml at 4 months (P less than 0.001 relative to "HbOC alone" group) and subsequently responded similarly to second and third doses of HbOC vaccine as did also the "HbOC alone" group. We conclude that combined passive/active immunization with bacterial polysaccharide immunoglobulin and HbOC at 2 months maintains antibody at concentrations thought to be protective (greater than or equal to 0.15 microgram/ml) without interfering with the active antibody response to second and third doses of HbOC at 4 and 6 months of age.

Bacterial Capsules↗