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Biomedical subjects

F K Lee

Publications and source records attributed to F K Lee.

At least 55 records · Page 3Linked to original sources
PubMed1994

The human sorbitol dehydrogenase gene: cDNA cloning, sequence determination, and mapping by fluorescence in situ hybridization.

The cDNA for human sorbitol dehydrogenase (SORD) has been cloned and sequenced. It translates into a peptide of 356 amino acid residues, one more than the sequence previously reported from peptide analysis. An extra alanine was found at the acetyl-blocked N-terminal, between positions 1 and 4. This matches the rat cDNA, which also has 356 amino acids, with an extra proline at position 3. Four other mis-matches were also observed, but these are all amino acid substitutions that occur outside proposed functionally important regions. Further work must be performed to determine whether these discrepancies represent polymorphic forms of the enzyme. The SORD gene was mapped by fluorescence in situ hybridization and found to occupy a single site on chromosome 15q15, indicating that it is a single-copy gene. This was confirmed by Southern blot hybridization. SORD is thought to be involved in the etiology of diabetic complications, and its deficiency has been linked to congenital cataracts. The cloned gene could be used as a probe to study the role of this enzyme in the pathogenesis of these diseases.

Amino Acid Sequence↗
PubMed1994

Lipooligosaccharide biosynthesis in pathogenic Neisseria. Cloning, identification, and characterization of the phosphoglucomutase gene.

The lipooligosaccharide (LOS) of pathogenic Neisseria is an important factor in disease pathogenesis. Little is known about the genes involved in neisserial LOS biosynthesis. To elucidate specific LOS biosynthetic genes, we screened a Tn916 library that was constructed in Neisseria meningitidis strain NMB. This strain expresses a single LOS that has an molecular mass of 4.5 kDa and binds monoclonal antibody (mAb) 3F11. This library was screened using a mAb panel that recognizes structural differences in neisserial LOS oligosaccharides. A stable LOS mutant of strain NMB was identified which we designated NMB-R6. This mutant expressed an LOS with an molecular mass of approximately 3.1-3.2 kDa and did not bind mAb 3F11. Genomic DNA from this mutant transformed N. meningitidis strain NMB to the tetracycline resistant NMB-R6 phenotype greater than 10(-4)/recipient/micrograms of DNA. In addition, we transformed Neisseria gonorrhoeae strain 1291 (LOS phenotype molecular mass 4.5 kDa, mAb 3F11+) to the NMB-R6 LOS phenotype with N. meningitidis NMB-R6 genomic DNA. Analysis of N. gonorrhoeae strain 1291-R6 LOS by mass spectroscopy showed that the LOS oligosaccharide structure is GlcNAc-->Hep2phosphoethanolamine-->2-keto-3-deoxymannooctuloson ic acid (where Hep is heptose). Sequence analysis showed that the transposon is inserted into the 3' end of a gene that has homology to the human phosphoglucomutase (PGM) gene. Sequence comparison indicated that the putative PGM gene in N. gonorrhoeae 1291 and N. meningitidis NMB had 92% identity at the DNA level. PGM and glucokinase activity was present in cell free extracts of N. meningitidis NMB and N. gonorrhoeae strain 1291. N. meningitidis NMB-R6 and N. gonorrhoeae strain 1291-R6 had no detectable PGM activity, whereas glucokinase activity was similar to the wild type strains. PGM activity can be reconstituted in N. meningitidis strain NMB-R6 by transformation with the cloned PGM gene. SDS-polyacrylamide gel electrophoresis demonstrated that NMB-R6 transformed with the PGM gene expressed the 3F11+, 4.5-kDa LOS of the parent NMB strain. The inability of N. meningitidis NMB-R6 and N. gonorrhoeae strain 1291-R6 to convert glucose 6-phosphate to glucose 1-phosphate results in the truncated LOS phenotype expressed by these mutants.

Amino Acid Sequence↗
PubMed1994

A prospective population-based study of HIV perinatal transmission.

OBJECTIVE: To estimate the perinatal HIV transmission rate and describe the natural history of infant HIV infection in a situation in which HIV status is known in more than 95% of delivering women. DESIGN: A cohort of HIV-exposed infants born between 7 July 1987 and 30 June 1990, whose mothers were identified by routine voluntary universal HIV testing, were followed using clinical and laboratory measures. SETTING: Grady Memorial Hospital, a major health-care site for individuals of lower socioeconomic status in Atlanta, Georgia, USA, with approximately 7000 deliveries per year. PATIENTS: HIV-exposed infants (n = 165), 98% of whom were African American. RESULTS: Annual maternal HIV seroprevalence increased from 0.58 to 0.86%. The annual proportion of HIV-positive women having a second delivery increased from 4.3 to 25%. Clinical outcome was known for 132 out of 165 infants (22 infected and 110 uninfected), the transmission rate was 17% (confidence interval, 11-24%). The rate declined to 11% by the third year of the study. Gestational growth, prematurity and mode of delivery were unrelated to infant outcome. There was a trend for intravenous drug use to be more common in mothers of infected infants (P = 0.08). After 35 months median follow-up of infected infants, eight out of 22 (36%) had an opportunistic infection (seven Pneumocystis carinii pneumonia); three out of 22 (14%) had lymphocytic interstitial pneumonia, and 10 out of 22 (45%) were asymptomatic or had only nonspecific symptoms. Cumulative mortality in infected infants was 9, 32 and 32% by 1, 2 and 3 years of age, respectively. CONCLUSION: In this cohort of HIV-exposed infants, perinatal HIV transmission was 17% overall. Factors affecting the transmission rate and possible future changes in the rate require further study.

AIDS-Related Opportunistic Infections↗
PubMed1994

Tn916-generated, lipooligosaccharide mutants of Neisseria meningitidis and Neisseria gonorrhoeae.

A library of Tn916-generated, tetracycline-resistant (Tc) mutants of the group B Neisseri meningitidis strain NMB was screened by using monoclonal antibodies (MAbs) that recognize structural differences in neisserial lipooligosaccharide (LOS). The LOS of parental strain NMB had a relative molecular mass of 4.5 kDa, reacted with MAbs 3F11 and 6B4 but not with MAb 4C4 or 6E4, and contained a lacto-N-neotetrose unit. Two phenotypically stable mutants, SS3 and R6, altered in LOS, were identified by colony immunoblots, electrophoresis, and Western immunoblots. The LOS of mutant SS3 was 3.4 kDa and reacted with MAbs 4C4 and 6E4 but not MAb 3E11 or 6B4. The LOS of mutant R6 was 3.1 to 3.2 kDa and reacted with MAb 6E4 but not MAb 3F11, 6B4, or 4C4. Thus, the LOSs of the R6 and SS3 mutants were predicted to contain different truncations of the core oligosaccharide. The LOS phenotype of each mutant was linked to Tc(r), as determined by transformation of the parent strain with DNA from the mutant. Southern hybridizations and single-specific-primer PCR revealed in each mutant a single truncated tn916 insertion which had lost genes required for mobilization. Tn916 mutagenesis was used to identify two distinct genetic sites in the meningococcal chromosome involved in biosynthesis of the oligosaccharide chain of LOS and to create genetically defined LOS mutants of N. meningitidis and Neisseria gonorrhoeae.

Antibodies, Bacterial↗
PubMed1994

Selective embryo reduction in multiple pregnancies resulting from assisted conception.

BACKGROUND: Assisted conception not only raises the pregnancy rate by treating infertility, but also increases the chance of obstetrical complication of multiple pregnancy. So it is important to develop a means by which the number of developing embryos can be reduced. METHODS: Eight multiply pregnant women (from triplets to octuplets) asked to have the number of viable fetuses reduced. By means of sonar guided puncture, a mixture of demerol and xylocaine was injected to the fetal thorax until the fetal heart ceased to beat. The procedures were done between the 7th and 11th week of gestational age. Repeated scans were done for three consecutive days to confirm the viability of the remaining fetuses. RESULTS: Except for vanishing twins, no serious complication was noted. For six of the women, 10 healthy births have resulted; the remaining two have ongoing pregnancies. CONCLUSIONS: The procedure described is an easy, safe and effective method to diminish obstetrical morbidity of multiple pregnancy.

Abortion, Induced↗
PubMed1993

Herpes simplex virus type 2 antibody in patients attending antenatal or STD clinics.

OBJECTIVE: To determine the prevalence of antibody to herpes simplex virus type 2 (HSV-2) in patients attending a general public antenatal clinic and three public sexually transmitted disease (STD) clinics in Sydney. BACKGROUND: Highly specific tests for herpes simplex type 2 antibody, using the glycoprotein G2, have been recently introduced, allowing determination of past asymptomatic infection. Overseas studies have confirmed the long held suspicion that asymptomatic infection is more common than clinical genital herpes. The seroprevalence of HSV-2 in antenatal and STD clinic patients varies markedly in different countries. These are the first data available for Australia by means of this highly specific test. DESIGN: Cross-sectional study of seroprevalence in these two patient groups. Sera used in the antenatal study were those submitted for routine antenatal screening for viral markers. PARTICIPANTS: Two hundred and twenty-nine consecutive patients attending the Westmead Hospital antenatal clinics, and 107 consecutive patients attending three public STD clinics. HYPOTHESES: That Australian populations show a relatively high prevalence of past asymptomatic infection with HSV-2; and that higher rates of infection will be found in patients attending STD clinics and with past or current histories of STDs. MAIN OUTCOME MEASURES: Comparison of HSV-2 seroprevalence between antenatal clinic patients and STD clinic patients; and associations of HSV-2 antibody with age, sex, occupation, country of birth, a history of current or past STDs and antibody to HSV-1. RESULTS: Antibody to HSV-2 was found in 14.5% of antenatal clinic patients and 40% of STD clinic patients. None of the antenatal patients and less than half of the seropositive STD clinic patients reported clinical genital herpes. Associations with age, socioeconomic status and previous HSV-1 infection were less marked than in studies from the United States. Female STD clinic patients had a significantly higher seroprevalence than males and three times the seroprevalence of age-matched antenatal clinic patients. The correlation between HSV-2 antibody and current gonorrhoea was more marked than that between HSV-2 and other STDs. CONCLUSION: Asymptomatic infection with HSV-2 is quite common in Australian antenatal patients and more common in patients with STDs, who have higher rates of sexual exposure.

Adult↗
PubMed1993

Immunoglobulin secretion by the normal and the infected newborn infant.

The development of quantitative single-cell immunoassays has provided a novel opportunity to demonstrate the isotype-specific immunoglobulin responses in normal and infected neonates. The reverse enzyme-linked immunospot assay was used to determine the number of immunoglobulin-secreting cells (IgSCs) in peripheral blood. Baseline numbers of IgSCs were established in 69 uninfected term and preterm infants within 5 days of birth; values above the 99th percentile were considered elevated. The IgSCs were also measured in 266 infants with proved or suspected infections or congenital anomalies. A subset of newborn infants was retested weekly. Few IgSCs (mostly IgMSCs) were detected within 5 days of birth in uninfected neonates, but by 1 month 77% had increased numbers of IgSCs, primarily IgASCs. Sixty-three (24%) of 266 study infants had increased IgSCs on initial sampling (predominantly IgMSCs); these included infants as immature as 25 to 27 weeks of gestational age; elevations in IgSCs were most frequent in infants with intrauterine infections. Increased numbers of IgSCs were uncommon in infants with early-onset sepsis in the first 5 days but were frequent by the second week, consistent with acquisition of infection near the time of delivery. We conclude that the presence of elevated numbers of IgSCs soon after birth may be a useful surrogate marker of untreated intrauterine infection. The development of predominantly IgASCs in the first month of life suggests postnatal exposure to common mucosal antigens.

Antibody-Producing Cells↗
PubMed1993

Clinical and serologic evaluation of neonates for congenital syphilis: a continuing diagnostic dilemma.

Neonates born to women with reactive serologic tests for syphilis were studied; the total of 116 included 18 who were symptomatic, 60 asymptomatic but possibly infected, and 38 asymptomatic and probably uninfected. The fluorescent treponemal antibody-absorption (FTA-ABS) 19S IgM test and an IgM capture ELISA for Treponema pallidum, both treponema-specific assays, and the reverse enzyme-linked immunospot (RELISPOT), which detects immunoglobulin-secreting cells and is a nonspecific indicator of infection, were evaluated. Sensitivities among symptomatic neonates were 88% (IgM ELISA), 73% (FTA-ABS), and 78% (RELISPOT). Specificities ranged from 97% to 100%. A major problem has been the inability to identify which asymptomatic but possibly infected neonate is really uninfected. Among 41 such babies who had all three tests done, 93% were negative by all assays, suggesting they were uninfected or recently infected. Strategies to accurately identify the truly uninfected asymptomatic newborn would prevent the unnecessary hospitalization of all at-risk infants, resulting in improved quality of care and reduced costs.

Adult↗
PubMed1991

Enumeration of human peripheral blood lymphocytes secreting immunoglobulins of major classes and subclasses in healthy children and adults.

The reverse enzyme-linked immunospot assay was modified to enumerate peripheral blood mononuclear cells (PBMC) secreting IgG1-4, IgA1-2, and IgM. Anti-human IgG F(ab')2 and mouse monoclonal antibodies specific to each of the isotypes were used as solid-phase capture antibodies and developing antibodies, respectively. Although attempts were also made to detect IgD- and IgE-secreting cells (SC), their numbers in the peripheral blood were too few to be reliably estimated. The assay was applied to study healthy subjects including 21 neonates within 3 days of birth, 44 1- to 48-month-old children, and 32 adults. Sixty percent of these neonates had IgM SC in small numbers (less than 20 per 10(6) PBMC), but only three neonates had IgSC of other isotypes. In contrast, by 1-2 months of age children had IgSC of all isotypes, including IgA2 and IgG4, often in higher numbers than adults. The relative frequencies of IgSC were IgA1 greater than IgG1 greater than IgM greater than IgG2 greater than IgG3 greater than IgG4 greater than IgA2 in the children and IgA1 greater than IgG1 greater than IgA2 greater than IgM greater than IgG4 greater than IgG2 greater than IgG3 in the adults. The order of the serum concentrations in the adults was IgG1 greater than IgG2 greater than IgA greater than IgM greater than IgG4 greater than IgG3. No correlation was found between the serum level and the IgSC number of individual isotypes (except for serum IgA and IgA1-SC). This new methodology should facilitate investigating the current status of immunoglobulin synthesis and the Ig repertoire in adults and children, in health and in disease.

Adult↗
PubMed1990

Early diagnosis of HIV infection in infants by detection of IgA HIV antibodies.

With the aim of achieving earlier diagnosis of human, immunodeficiency virus (HIV) infection in infants, IgA and IgM HIV antibodies in serum samples from babies born to seropositive mothers were assayed by immunoblot and enzyme-linked immunosorbent assay after removal of IgG with recombinant protein G. 64 samples were from 38 HIV-infected babies with Centers for Disease Control classifications of P1 or P2. Among these infected children IgA HIV antibodies were present in all 23 samples from those older than 12 months, in 12 of 18 samples from babies aged 6-12 months, in 5 of 10 samples from babies aged 3-5 months, and in 2 of 13 from babies under 3 months old. The 6 IgA-negative samples from infants over 6 months were all from infants with severe AIDS and/or hypogammaglobulinaemia. IgA HIV antibodies were present in twice as many samples as IgM HIV antibodies (66% vs 33%). No IgM or IgA HIV antibodies were detected in infants who subsequently seroreverted or in infants born to seronegative mothers. The correlation of the serological results with clinical information on each child suggests that detection of IgA HIV antibodies is an effective method for early diagnosis of HIV-infected infants without signs of infection.

AIDS Serodiagnosis↗
PubMed1990

A cross-sectional study of herpes simplex virus types 1 and 2 in college students: occurrence and determinants of infection.

Occurrence rates and determinants of infection with herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) were measured in first- and fourth-year undergraduate students at a state university. This cross-sectional multistage probability sample survey included sociodemographic characteristics, sexual behavior patterns, disease history, and HSV type-specific antibody status. The prevalence of HSV-1 antibody was 37.2% in freshmen and 46.1% in fourth-year students; that for HSV-2 antibody was 0.4% and 4.3%, respectively. A history of cold sores was obtained in 25.6% of the freshmen; none had a history of manifest genital herpes. A history of cold sores was obtained in 28% and a history of genital herpes in 1.1% of the fourth-year students. The case-weighted prevalence of HSV-1 and HSV-2 antibodies was found to be significantly elevated for a number of student characteristics. However, multiple logistic regression analyses indicated that the significant predictors of HSV-1 antibodies in this population were female gender, black race, first intercourse at age less than or equal to 15 years, total years of sexual activity, history of a partner with oral sores, and a personal history of a non-HSV sexually transmitted disease (STD). Predictors of HSV-2 antibody were black race, duration of sexual activity, and history of a non-HSV STD.

Adult↗
PubMed1990

Herpes simplex virus type 2 and other genital ulcerative infections as a risk factor for HIV-1 acquisition.

We studied the role of genital ulcerative infections for acquisition of human immunodeficiency virus type 1 (HIV-1) infection in a cohort of 989 homosexual men in Amsterdam between October 1984 and December 1988. Among 53 HIV-1 seroconverters serological and anamnestic data were gathered regarding herpes simplex virus type 2 (HSV-2) and syphilis in the 6 months before seroconversion. For statistical analysis a control who remained seronegative during the same interval was selected at random for each HIV-1 seroconverter. A significant difference between the prevalence of HSV-2 antibodies among HIV-1 seroconverters and controls was found (72% vs 38%). HSV-2 seroconversions among men initially seronegative for HSV-2 were found among three of 18 HIV-1 seroconverters and among three of 36 controls. (O.R. = 2.2, 95% C.I. 0.4-12.1). Self-reported cases of anogenital herpes were found more frequently among HIV-1 seroconverters (8) than among controls (4). One case of syphilis was diagnosed among HIV-1 seroconverters, and one among controls. Summing up these cases we assessed the total number of genital ulcerative infections: 12 among HIV-1 seroconverters and eight among controls (23 vs 15%, O.R. 1.7, C.I. 0.6-4.62). These data suggest little evidence for genital ulcerative infections being an important independent risk factor for HIV-1 acquisition among homosexual men in Amsterdam during the time period studied.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Sero-epidemiological and -sociological patterns of herpes simplex virus infection in the world.

A newly developed Herpes simplex virus (HSV) type 1 and type 2 enzyme immunoassay has been applied to over 40,000 sera from different populations in the US and 17 other countries on all 5 continents. The HSV-1 antibody patterns found permit the current and past socioeconomic status, as well as the extent of oral-genital sexual contact, to be deduced for various populations. The HSV-2 antibody results provide an objective measure of various aspects of sexual behavior: extent of polypartnerism in the subjects tested (or their contacts), early age of sexual experience and acquisition rates of genital herpes. It has thus been possible to extend sero-epidemiology to sero-sociology which can provide objective markers for sexual behavior and effects of intervention or educational approaches. Besides such markers having potential applicability for monitoring other STDs, such as HIV infection, recent studies also support a possible role for HSV infections to increase the transmissibility, not only of HIV-1, but also of HTLV-1.

Age Factors↗
PubMed1989

A seroepidemiologic survey of the prevalence of herpes simplex virus type 2 infection in the United States.

The prevalence of infection with the genital herpes simplex virus type 2 (HSV-2) has been difficult to ascertain, primarily because of the large percentage of subclinical cases and the limitations in specificity of serologic assays for antibody to HSV-2. To obtain an improved estimate of the distribution of HSV-2 infection in the United States, we used an HSV type-specific antibody assay to test serum samples from 4201 participants in the second National Health and Nutrition Examination Survey. The results in our sample indicate that in the period from 1976 to 1980, 16.4 percent of the U.S. population 15 to 74 years of age (approximately 25 million persons) was infected with HSV-2 (95 percent confidence interval, 14.2 to 18.6 percent). Age and race were the demographic factors associated most strongly with the presence of HSV-2 antibody. The prevalence of the antibody increased from less than 1 percent in the group under 15 years old to 20.2 percent in the group 30 to 44 years old; it increased only slightly thereafter. In the oldest group, 60 to 74 years of age, the prevalence was 19.7 percent in whites and 64.7 percent in blacks. Among blacks of all age groups, but not whites, higher rates were observed in women than in men. The associations were weaker with respect to marital status, income, education, urban residence, and region of the country. After control for age, sex, and race, only the association with marital status remained significant; the rate was increased in persons previously married--i.e., divorced, separated, or widowed. We conclude that the prevalence of HSV-2 infection in the United States is higher than has previously been recognized and that many infections with this sexually transmitted virus may be subclinical.

Adolescent↗
PubMed1989

ELISPOT: a new approach to studying the dynamics of virus-immune system interaction for diagnosis and monitoring of HIV infection.

A new approach to detect and enumerate HIV-specific antibody-secreting cells (ASC) in the peripheral blood was developed using the enzyme-linked immunospot (ELISPOT) methodology. ASC to an HIV envelope recombinant protein were demonstrated in 75% of 16 adults and 72% of 21 children with untreated AIDS or ARC and in 63% of 34 asymptomatically infected adults but in none of the 51 HIV antibody-negative individuals. Only 1 of the 13 adults receiving AZT therapy yielded a positive reaction, and 27% of the 30 infants born to seropositive mothers were found to have HIV-ASC. The number of HIV-ASC in positive individuals varied from 8 to 202 per 10(6) circulating mononuclear cells. The reactivity was specifically inhibited by soluble HIV antigen and was abrogated by cycloheximide, indicating that the observed reaction was the result of de novo synthesis of HIV-specific antibodies. Nonspecific polyclonal B cell activation was unlikely to be responsible for the results observed as no reactivity was found to a common antigen, tetanus toxoid. Since circulating antigen-specific ASC reflect persistent or recent antigenic stimulation, our findings indicate that this new approach could provide a dynamic perspective of the natural course of virus-immune system interactions in individuals infected with HIV, as well as in those undergoing prophylactic or therapeutic interventions.

AIDS-Related Complex↗
PubMed1989

Clinical and serological outcome of genital herpes simplex virus (HSV) type 2 inoculation following oral HSV type 1 infection in guinea-pigs.

The clinical and serological outcome of genital herpes simplex virus type 2 (HSV-2) inoculation in animals previously orally infected with HSV type 1 was evaluated. A prior HSV-1 oral infection modified the genital HSV-2 infection so that only four of 18 (22%) animals were initially symptomatic although all but one animal shed HSV-2 from the cervicovaginal area for at least 5 days following inoculation. Three of four animals with symptomatic initial disease also developed recurrences, as did an additional six animals that did not manifest acute genital disease. Anti-glycoprotein gG-1 antibody was found in 17 of 18 animals with only an HSV-1 infection and anti-gG-2 antibody in all of nine animals with only an HSV-2 infection. Anti-gG-2 antibody was detected in eight of 17 animals with a prior HSV-1 infection following HSV-2 inoculation and one had an indeterminate response. Eight of these nine animals developed recurrent genital disease compared to one of eight that did not respond to gG-2 (P less than 0.006). Thus a prior oral HSV-1 infection modified both the initial presentation of HSV-2 infection and the HSV type-specific serological response.

Animals↗
PubMed1989

Herpes simplex virus type 2 antibodies: high prevalence in monogamous women in Costa Rica.

We studied the prevalence of antibody to Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) in 766 randomly selected Costa Rican women 25-59 years of age in a national household survey in 1984-1985. Overall, 97.1% were seropositive for HSV-1 and 39.4% for HSV-2. Only 1.1% of HSV-2 seropositive women gave a history of symptomatic genital herpes. HSV-2 virus antibody increased with age and with the number of lifetime sexual partners. HSV-2 seroprevalence among women who reported only 1 lifetime sexual partner was almost twice as high as the prevalence among women who denied sexual experience (30.5% vs. 17.7%) and reached 79.2% among women with greater than or equal to 4 partners. HSV-2 seroprevalence was lower among women whose partners used condoms: 28.9% for those who had used condoms for at least 2 years vs. 44.3% for those who never used condoms.

Adult↗