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Biomedical subjects

A L Morrow

Publications and source records attributed to A L Morrow.

At least 19 recordsLinked to original sources
PubMed1992

Concentration of milk secretory immunoglobulin A against Shigella virulence plasmid-associated antigens as a predictor of symptom status in Shigella-infected breast-fed infants.

We conducted a prospective, community-based study of healthy breast-fed Mexican infants to determine the protective effects of anti-Shigella secretory IgA antibodies in milk. Milk samples were collected monthly, and stool culture specimens were obtained weekly and at the time of episodes of diarrhea. Nineteen breast-fed infants were found to have Shigella flexneri, Shigella boydii, or Shigella sonnei in stool samples. Ages of the 10 infants with symptomatic infection and the nine with asymptomatic infection did not differ significantly. Milk samples collected up to 12 weeks before infection were evaluated by enzyme-linked immunosorbent assay for secretory IgA antibodies against lipopolysaccharides of S. flexneri, S. boydii serotype 2, S. sonnei, and virulence plasmid-associated antigens. The geometric mean titers of anti-Shigella antibodies to virulence plasmid-associated antigens in milk received before infection were eightfold higher in infants who remained well than in those in whom diarrhea developed. The significance of milk secretory IgA directed against lipopolysaccharide was less clear. We conclude that human milk protects infants against symptomatic shigella infection when it contains high concentrations of secretory IgA against virulence plasmid-associated antigens.

Antigens, Bacterial↗
PubMed1992

Association between severity of gastrointestinal prodrome and long-term prognosis in classic hemolytic-uremic syndrome.

To determine whether severity of the prodromal gastrointestinal illness is associated with the course and complications of the extraintestinal manifestations of hemolytic-uremic syndrome, we conducted a retrospective review of children (n = 509) hospitalized with hemolytic-uremic syndrome. Those who came to the hospital with colitis and rectal prolapse associated with hemolytic-uremic syndrome (group I, n = 40) were compared with an equal number of time-matched children with hemolytic-uremic syndrome but without prolapse (group II). Children in group I had evidence of more severe colitis than children in group II had, as indicated by increased frequency of bloody diarrhea (p less than 0.001) and longer duration of diarrhea (p less than 0.001). However, they also had more severe extraintestinal manifestations during hemolytic-uremic syndrome, including edema (p less than 0.0001), severe thrombocytopenia (p less than 0.0001), prolonged anuria (p less than 0.001), and seizures (p = 0.036). Long-term prognosis for recovery of renal function was worse for group I than group II. Within group II, patients with bloody diarrhea had milder extraintestinal illness than those with prolapse but more severe extraintestinal illness than those with watery diarrhea. Analysis of Kaplan-Meier survival curves demonstrated a better prognosis for return of normal renal function in the children with watery diarrhea but without prolapse (p = 0.009) than in children with bloody diarrhea or prolapse. These data demonstrate that the severity of the gastrointestinal prodrome reflects the severity of the extraintestinal acute microangiopathic process and the resulting long-term outcome. Widespread vascular damage, often followed by permanent sequelae, is characteristic of patients with the most severe colitis.

Adolescent↗
PubMed1992

Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants.

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Animals↗
PubMed1992

Trimethoprim-resistant Escherichia coli in households of children attending day care centers.

Children in day care centers are frequently colonized with trimethoprim-resistant Escherichia coli. The frequency of transmission to family members was studied. Colonization with trimethoprim-resistant E. coli was detected in 13 (57%) of 23 day care center children. Among the 50 (98%) of 51 household members tested, colonization was detected in 13 (26%), representing 12 (52%) of 23 households tested. Households of colonized center children had significantly more colonized members than did households of noncolonized children (odds ratio, 13.3; 95% confidence interval, 1.3-172.6; P = .01). There was a trend toward higher prevalence of colonization in mothers (35%) and siblings (30%) than in fathers (12%). The same plasmid profiles of trimethoprim-resistant E. coli from center children were found among 8 (67%) of 12 colonized households. There was no association between antibiotic use and fecal colonization with trimethoprim-resistant E. coli. Thus, transmission of trimethoprim-resistant E. coli among children within day care centers and from center children to household members is common.

Carrier State↗
PubMed1992

Intermediate resistance of Streptococcus pneumoniae to penicillin in children in day-care centers.

This study was performed to determine the prevalence, serotypes and antibiotic susceptibility patterns of penicillin-resistant Streptococcus pneumoniae in children younger than 3 years of age in day-care centers in Houston, TX. Nasopharyngeal cultures were obtained on two occasions, in March and May, 1989, from 140 children in 4 day-care centers. All penicillin-resistant S. pneumoniae organisms isolated in this study had minimum inhibitory concentrations to penicillin of between 0.1 and 0.5 microgram/ml and were thus intermediately resistant. No highly resistant S. pneumoniae (minimum inhibitory concentration > or = 1.0 microgram/ml) was isolated in this study. Nasal carriage of S. pneumoniae occurred in 39% of children; carriage of intermediately resistant S. pneumoniae occurred in 4% of children. Of the 39% of children who carried S. pneumoniae, 11% carried intermediately resistant strains. In one day-care center with a prior history of intermediately resistant S. pneumoniae (Center 1), the prevalence of intermediate penicillin resistance was significantly (P = 0.047) higher than in the other three centers. Among children surveyed twice 15% of Center 1 children carried an intermediately penicillin-resistant strain at least once, whereas in the other centers 3% of children carried an intermediately resistant strain at least once. Sixty-two percent of intermediately penicillin-resistant strains were resistant to multiple antibiotics and all were serotype 14. Intermediately penicillin-resistant S. pneumoniae isolates were prevalent among young children in day-care centers in Houston and may persist in some day-care centers and become endemic.

Child Day Care Centers↗
PubMed1992

A comparison of herpes simplex virus specific antibodies found in human milk and serum.

It is not known if milk antibody protects infants from herpes simplex virus (HSV) infection. As a first step to test this hypothesis, anti-HSV antibodies were studied in human milk. Paired serum and milk samples were analyzed for anti-HSV antibodies by ELISA, Western blot analysis (WBA), neutralization (NT) plaque assay, and antibody-dependent cellular cytotoxicity (ADCC) assay. Nineteen of the 20 serum samples showed anti-HSV activity by ELISA and ADCC, and 18 showed activity by WBA and NT. We found a significant association between the immunoassays for detection of anti-HSV antibodies in sera. Fewer of the human milk samples showed anti-HSV activity; only one milk sample was positive by ELISA and one by NT assay, four by ADCC and 12 by WBA. The milk sample from the seronegative donor was also negative. We found a poor association of antibody titers in human milk and serum antibody titers using ELISA, NT, and ADCC assays. There was a significant (p = 0.022) association between serum and milk results using WBA. Among the four assays, WBA was the most sensitive for antibody detection. It will be used in an on-going prospective study to determine the role of anti-HSV antibody in the protection against HSV infections in infants.

Antibodies, Viral↗
PubMed1991

Stress-induced elevations of gamma-aminobutyric acid type A receptor-active steroids in the rat brain.

A 3 alpha-hydroxy A-ring-reduced metabolite of progesterone, 3 alpha-hydroxy-5 alpha-pregnan-20-one (allopregnanolone), and one of deoxycorticosterone (DOC), 3 alpha,21-dihydroxy-5 alpha-pregnan-20- one (allotetrahydroDOC), are among the most potent known ligands of gamma-aminobutyric acid (GABA) receptors designated GABAA in the central nervous system. With specific radioimmunoassays, rapid (less than 5 min) and robust (4- to 20-fold) increases of allopregnanolone and allotetrahydroDOC were detected in the brain (cerebral cortex and hypothalamus) and in plasma of rats after exposure to ambient temperature swin stress. Neither steroid was detectable in the plasma of adrenalectomized rats either before or after swim stress. However, allopregnanolone, but not allotetrahydroDOC, was still present in the cerebral cortex (greater than 3 ng/g) after adrenalectomy. These data demonstrate the presence of allopregnanolone and allotetrahydroDOC in brain and show that acute stress results in a rapid increase of these neuroactive steroids to levels known to modulate GABAA receptor function.

Adrenalectomy↗
PubMed1991

The effect of diaper type and overclothing on fecal contamination in day-care centers.

Fecal coliform contamination of environmental surfaces and hands in the day-care center is common. This study evaluated the effect of two diaper types on fecal contamination. Ten rooms in four day-care centers containing 141 children were studied in a prospective, randomized, crossover study. A total of 2946 samples were cultured during the 9-week study. Fecal coliforms were isolated from 307 inanimate objects (15%), 73 toy balls (46%), and 131 hands (17%). The number of contaminated inanimate objects was significantly less in rooms where paper diapers were worn when compared with that in rooms where double cloth diapers with plastic overpants were worn and in rooms where clothes were worn over diapers. Inanimate object cultures had more contamination in rooms in which diarrhea had occurred. Containment of feces by overclothes and diaper type may be important in decreasing transmission of enteric pathogens in day-care environments.

Child Day Care Centers↗
PubMed1991

Environmental contamination in child day-care centers.

Enteropathogens associated with outbreaks of diarrhea in day-care centers are spread by the fecal-oral route through contaminated hands or environmental objects. This prospective study was undertaken to determine the prevalence of fecal coliform contamination in day care. Ten rooms in six centers housing 121 children less than 2 years of age were studied for 13 weeks (February to May 1988). Inanimate objects (n = 1,275), toy balls (n = 724), and hands (n = 954) were cultured 1-3 times per week. Fecal coliform contamination was common and was greater (p less than 0.05) for objects, toy balls, and hands of children in toddler compared with infant rooms. In five rooms in which clothes were worn over diapers, there was a significantly lower prevalence of fecal coliform contamination of toy balls (p less than 0.005), inanimate objects (p less than 0.05), and hands (p less than 0.001) when compared with rooms in which overclothes were not worn. Occurrence of diarrhea was significantly associated with increased contamination of hands (p = 0.001). Stool and environmental isolates from individual rooms had the same plasmid patterns, which were unique to each center. In summary, fecal coliform contamination of environmental objects and hands of children and caregivers in day-care centers is common; toy balls can serve as sentinels of contamination; fecal coliform contamination can be significantly decreased by use of overclothes; and Escherichia coli strains from stool showed the same plasmid patterns.

Child Day Care Centers↗
PubMed1991

Diarrhea in children newly enrolled in day-care centers in Houston.

Diarrhea is a common illness among children in day-care centers (DCC). We hypothesized that the incidence of diarrhea was greater among children in their first 1 or 2 months after enrollment in a DCC than in any subsequent period in day care. We followed 442 children younger than 2 years of age enrolled in 13 randomly selected DCCs for the occurrence of diarrhea during a 14 1/2-month period. Parents completed standardized baseline questionnaires and research nurses visited the DCC twice weekly to record the occurrence of diarrhea and to collect stool specimens. Incidence rates, rate ratios, chi square statistics and 95% confidence intervals were calculated for crude and stratified analyses. The diarrheal incidence rate of 4.4 cases/child-year in the first 4 weeks in the centers was significantly (rate ratio, 1.6; confidence interval, 1.3 to 2.1; P less than 0.01) higher than the 2.7 cases/child-year incidence rate of diarrhea in subsequent weeks. The effects of gender, ethnicity, age, DCC size, previous DCC attendance and season were examined and did not account for the association observed between recent enrollement and risk of diarrheal illness. Rotavirus was identified in 18% of cases of diarrhea, but no association was seen with recent enrollment in DCC. A significantly higher incidence of diarrhea occurred in males compared with females (P less than 0.002) and in younger children (P less than 0.001) compared with older children. Diarrhea is common in children in DCCs and occurs significantly more frequently in children during their first 4 weeks in a DCC.

Age Factors↗
PubMed1991

Risk of enteric infection associated with child day care.

Pediatricians may advise parents that diarrhea is a frequent occurrence among infants and toddlers in day care and that diarrhea is usually mild and self-limited. A child newly enrolled in a day-care facility is at a particularly high risk for developing a diarrheal illness within the first month after enrollment, but the risk has been found to decrease as children remain in the same setting. Children who have diarrhea, fever, or vomiting of infectious origin should be isolated from well children. Infants and toddlers may return to the day-care environment when their diarrhea subsides and they are feeling well. Transmission of enteric infection from the child attending day-care center to other members of the family is possible; therefore, family members should also routinely practice good hygiene. Child-care providers should enforce written guidelines that establish hygienic practices and outline the management of ill children. Parents should be encouraged to read these policies and observe practices within the child-care setting before deciding to enroll their child in any care setting. The National Standards for out-of-home child care scheduled for release in 1991 will be important reading and a comprehensive reference for pediatricians who choose to be a child health consultant to one or more day-care facilities.

Child Day Care Centers↗
PubMed1991

Prolonged ethanol inhalation decreases gamma-aminobutyric acidA receptor alpha subunit mRNAs in the rat cerebral cortex.

Ethanol administration to rats by ethanol vapor inhalation (14 days) results in a 40-50% reduction in the level of gamma-aminobutyric acidA (GABAA) receptor alpha 1 subunit mRNAs [4.4 and 4.8 kilobases (kb)] in the cerebral cortex. The level of alpha 2 subunit mRNA (8.0 kb) was also reduced by 29%, whereas there was no effect of prolonged ethanol exposure on the level of alpha 3 subunit mRNA (3.1 kb). Ethanol exposure did not alter the steady state levels of cerebral cortical glutamic acid decarboxylase or beta-actin mRNAs. Moreover, no alterations in the levels of total RNA, poly(A)+ RNA, or rRNA were observed, suggesting that the ethanol-induced reductions in GABAA receptor alpha 1 and alpha 2 subunit mRNAs were not the result of a generalized effect of ethanol administration on transcription or mRNA turnover. These ethanol-induced reductions in GABAA receptor alpha subunit mRNAs may underlie alterations in GABAA receptor function or number observed following prolonged ethanol exposure in rats.

Administration, Inhalation↗
PubMed1991

Knowledge and attitudes of day care center parents and care providers regarding children infected with human immunodeficiency virus.

It was hypothesized that parents and child care providers are not prepared to accept children infected with human immunodeficiency virus (HIV), who are increasing in number, into the day care center setting. To determine their knowledge and attitudes toward HIV transmission, 219 parents in 4 day care centers and 176 care providers in 12 day care centers were given confidential questionnaires. More than 98% of respondents knew that sex and needle sharing can transmit HIV; 84% of parents and 77% of care providers knew that contact with blood can transmit HIV. There was, however, uncertainty about transmission via many common contacts in day care centers: human bites, urine, stool, tears, and vomit; kissing; sharing of food and eating utensils; and diaper changing areas. Only 43% of parents said they would allow their child to stay in the same room with a child who was infected with HIV. In a multiple logistic regression model, the unwillingness of parents to have their child stay in the same room with a child who was infected with HIV was significantly (P less than .0001) associated with black ethnicity, beliefs that such a child is likely to infect others (40%) and is dangerous to others (58%), and fear of their child being exposed to HIV (86%). Care providers' unwillingness to care for a child infected with HIV in the classroom (48%) was significantly (P less than .0001) associated with beliefs that such a child is likely to infect others (44%) and that common day care center contacts can transmit HIV (62%).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1991

Family physicians' attitudes about dietary advice.

Family physicians in Vermont were surveyed to assess their attitudes and practices concerning the provision of dietary and nutritional advice to their patients. The response rate was 82%. Ninety-six percent of respondents considered that nutrition counseling was their responsibility, and the attitudes and beliefs of most of them concurred with the presently accepted relationships between diet and coronary artery disease. Sixty-five percent of respondents reported making dietary recommendations to less than 40% of their nondiabetic patients under the age of 40. Only 27% of respondents routinely took a dietary history, but those who did were significantly more likely to counsel a larger proportion of their patients than those who did not. Serum cholesterol was reported as being measured in about 35% of adults, and the average level of serum cholesterol at which dietary advice would be given was 237 +/- 15 mg/dL. Most reasons for not giving dietary advice were related to the physician's perception that the patient was not at risk for a diet-related disease. Perceived patient lack of interest and lack of compliance were also important reasons, but lacking time or not being reimbursed were much less frequently cited, although adequate financial reimbursement for giving such advice was considered a moderate or major problem by 45% of family physicians.

Adolescent↗
PubMed1990

Gamma-aminobutyric acid (GABAA) receptor-function in a rat model of hepatic encephalopathy.

The functional activity of the gamma-aminobutyric acid (GABAA) receptor-chloride ionophore complex was studied in rats with hepatic encephalopathy (HE) secondary to thioacetamide-induced fulminant hepatic failure (FHF). Muscimol stimulation and benzodiazepine potentiation of GABA receptor-mediated 36Cl- uptake into cerebral cortical synaptoneurosomes was compared in HE and control rats. [3H]Flumazenil binding assays were conducted to determine whether the levels of endogenous benzodiazepine-like ligands in extracts of cortex were increased with stages of encephalopathy in this animal model of HE. In both control and HE rats maximal uptake of 36Cl- via the GABAA receptor complex occurred at muscimol concentrations of 30 microM. Potentiation of muscimol-stimulated 36Cl- uptake into synaptoneurosomes by diazepam (5 microM) was equivalent in both groups. Aqueous extracts of proteolytically digested homogenates of cerebral cortices prepared from control and HE rats were effective in stimulating 36Cl- uptake into synaptoneurosomes. Alkaline organic extracts of proteolytically digested homogenates of cerebral cortices from HE rats were more effective than corresponding extracts from controls at inhibiting the binding of [3H]flumazenil. Inhibition of [3H] fumazenil binding by organic extracts derived from the cerebral cortices of HE rats did not increase with progression of encephalopathy. The results show that muscimol-stimulated 36Cl- uptake into synaptoneurosomes and, consequently, GABAA receptor-mediated chloride channel function are not significantly altered in the model of HE studied and are consistent with the hypothesis that HE results in an increased availability of one or more endogenous ligands which can augment GABA receptor-gated chloride conductance.

Animals↗
PubMed1990

Radioimmunoassay of 3 alpha-hydroxy-5 alpha-pregnan-20-one in rat and human plasma.

A radioimmunoassay for measuring 3 alpha-hydroxy-5 alpha-pregnan-20-one in plasma has been developed. Polyclonal antibodies were raised in rabbits against 3 alpha-hydroxy-20-oxo-5 alpha-pregnan-11 alpha-yl carboxymethyl ether coupled to bovine serum albumin. 3 alpha-Hydroxy-5 alpha-pregnan-20-one was purified from either extracts of plasma by high-performance liquid chromatography. These antibodies were then used for the radioimmunoassay of this centrally active progesterone metabolite in rat and human plasma. 3 alpha-Hydroxy-5 alpha-pregnan-20-one was detected in plasma from female rats on the day of estrus (2.0 to 9.3 ng/ml) and in the plasma of women during the luteal phase of the menstrual cycle at levels ranging from 0.25 to 2.5 ng/ml. The latter was highly correlated with plasma progesterone levels.

Animals↗