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Biomedical subjects

M H Kim

Publications and source records attributed to M H Kim.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of the reverse transcriptase of 1731, a Drosophila melanogaster retrotransposon.

The nucleotide sequence of 1731, a retrotransposon cloned from the genome of Drosophila melanogaster, reveals a structural similarity with the proviral form of the retroviruses including a pol-like gene containing a putative reverse-transcriptase(RT)-coding sequence. Diverse parts of that sequence were subcloned and expressed in Escherichia coli. It has been demonstrated that the expression of the RT-like sequence, when translated, gives rise to peptides displaying enzyme activity characteristic of a true RT enzyme. In addition, rabbit antisera directed against such recombinant proteins allowed us to detect an immunoreactive protein of around 110 kDa, which was only present in D. melanogaster cell lines, but not in cells derived from Drosophila virilis or Drosophila hydei, whose genomes do not bear the 1731 element. This protein is expected to correspond to a non-processed pol-gene translated product and cosediments with virus-like particles exhibiting RT activity.

Amino Acid Sequence↗
PubMed1992

Clonal basis for resurgence of serious Streptococcus pyogenes disease in the 1980s.

During the 1980s there was a resurgence of serious Streptococcus pyogenes infections with complications, including rheumatic fever, sepsis, severe soft-tissue invasion, and toxic-shock-like syndrome (TSLS). We have investigated the suggested association between expression of a scarlet fever toxin, SPE A, and systemic toxicity, and the possibility that a new highly virulent clone of S pyogenes has emerged and spread world wide. We studied serotype M1 strains, the serotype most commonly associated with serious complications. 19 isolates from patients with sepsis, with or without TSLS, and 48 from patients with uncomplicated pharyngitis or superficial skin infection were subjected to restriction-enzyme digestion and electrophoresis; 56 isolates (19 serious, 37 uncomplicated disease) were then examined by hybridisation to an speA gene probe. 17 (90%) of the 19 serious-disease isolates had a characteristic ("invasive", I) restriction-fragment profile and were positive for the speA gene. Significantly lower proportions of the isolates from patients with uncomplicated disease had the I profile (21/48 [44%]; p = 0.0035) and speA (20/37 [54%]; p less than 0.001). These findings suggest that the strains from patients with serious disease are a unique clone, which became the predominant cause of severe streptococcal infections in the United States and elsewhere in the late 1980s.

DNA, Bacterial↗
PubMed1992

The effect of platelet activating factor on different phases of murine in vitro fertilization.

PURPOSE: Our purpose was to examine the effect of platelet activating factor (PAF) in different phases of mouse in vitro fertilization and optimal parameters that would enhance the fertilization rate. DESIGN AND SETTINGS: Various PAF concentrations (10(-7) to 10(-5) M) were selected to investigate its effect on three phases of mouse in vitro fertilization (i.e., sperm capacitation, sperm/oocyte coincubation, and preimplantation embryo growth) in three experimental groups: (I) with PAF treatment in the first phase, (II) with PAF treatment adopted in the first and second phases, and (III) with PAF treatment implemented in all three phases. RESULTS: The improvement of the fertilization rate in PAF treatment groups over the control group ranges from 6.5 to 19.0% (P < 0.05-P < 0.001). The highest enhancement of fertilization rate was achieved under the condition of PAF treatment (10(-6) M) through sperm capacitation and sperm/oocyte coincubation phases. CONCLUSION: The PAF concentration of 10(-6) M in sperm capacitation and sperm/oocyte coincubation yielded the greatest improvement in fertilization. However, continuing PAF treatment after sperm/oocyte coincubation had no beneficial effect on fertilization and preimplantation development.

Animals↗
PubMed1992

The effect of preovulatory peritoneal fluid from cases of endometriosis on murine in vitro fertilization, embryo development, oviduct transport, and implantation.

OBJECTIVE: The null hypothesis of our study is that the success of in vitro and in vivo murine fertilization and embryo development is not decreased by gamete exposure to peritoneal fluid from superovulated patients with endometriosis. STUDY DESIGN: A murine in vitro fertilization model was used to test the effects of endometriosis versus nonendometriosis peritoneal fluid at concentrations of 1%, 5%, and 10% versus an unsupplemented control. Fertilization and blastocyst formation were compared by analysis of variance. In a second experiment superovulated mice were given intraperitoneal injections of endometriosis or nonendometriosis fluid or saline solution 8 hours after human chorionic gonadotropin and then mated. Some mice were killed 3 days after coitus to assess embryo number, cleavage stage, and uterine versus tubal position by means of analysis of variance and covariance with repeated measures. Others were killed 12 days after coitus with the mean number of implantations per animal between groups compared by Student's t test. RESULTS: In vitro fertilization rates decreased as peritoneal fluid concentration increased in both the endometriosis (65%, 43%, 33%) and nonendometriosis (65%, 52%, 35%) groups at 1%, 5%, and 10% peritoneal fluid concentration, respectively. Mice receiving intraperitoneal endometriosis or nonendometriosis fluid or saline solution injections showed no differences in embryo number, cleavage, uterine versus tubal position, or mean implantation number. CONCLUSION: Peritoneal fluid from superovulated patients had no differentially negative effect when compared with the effect of nonendometriosis peritoneal fluid on murine in vitro or in vivo fertilization and embryo development, tubal embryo transport, or implantation.

Adult↗
PubMed1992

Streptococcal toxic shock syndrome due to noninvasive pharyngitis.

Serious infections due to group A beta-hemolytic streptococcus (GABHS) have been reported with increasing frequency in recent years. We report a case of toxic shock syndrome (TSS) due to GABHS pharyngitis in an otherwise healthy 14-year-old boy. The organism was found to produce toxin A. To our knowledge, this is the second reported case of streptococcal TSS associated with the production of toxin A that is not associated with an invasive disease and the first case associated with a documented rise in the level of antibody to the streptococcal toxin itself. Clinicians must be especially vigilant for this entity in patients who have streptococcal pharyngitis because early recognition and institution of aggressive supportive therapy can be lifesaving.

Adolescent↗
PubMed1992

Human immunodeficiency virus seropositivity in critically ill neonates in the south Bronx.

Cord blood was anonymously screened to determine the prevalence of human immunodeficiency virus (HIV) seropositivity in neonates admitted to the neonatal intensive care unit (NICU) at the Bronx Lebanon Hospital Center, located in the South Bronx. We speculated that factors leading to admission to the NICU such as low birth weight, prematurity and being small for gestational age would also be associated with an increased prevalence of HIV seropositivity. During the study period the prevalence of HIV seropositivity was 11.6% in the NICU population. There was no significant difference in maternal age, gravidity, race and sex in HIV-seropositive vs. HIV-seronegative newborns. There was a significantly increased incidence of maternal drug use (P less than 0.01), babies small for gestational age (P less than 0.005) and microcephaly (P less than 0.02) in seropositive vs. seronegative NICU babies. The results of this study suggest that the NICU population may comprise a significant number of infants of HIV-infected mothers.

Critical Illness↗
PubMed1992

Effect of glycerol monolaurate on bacterial growth and toxin production.

Glycerol monolaurate (GML) is a naturally occurring surfactant that has potential use as an additive to tampons and wound dressings to reduce the incidence of certain bacterial toxin-mediated illnesses. In vitro studies were undertaken to evaluate the effect of GML on the growth of and toxin production by potentially pathogenic bacteria. GML inhibited the growth of clinical isolates of group A, B, F, and G streptococci at concentrations of 10 to 20 micrograms/ml. Exotoxin production, including that of pyrogenic exotoxins and hemolysins, was reduced by concentrations of GML that were below those inhibitory for growth as well as growth inhibitory. The growth of Staphylococcus aureus strains from patients with toxic shock syndrome and scalded skin syndrome was inhibited or delayed in the presence of 100 to 300 micrograms of GML per ml. Growth inhibition by GML could be overcome by the production of lipase. S. aureus elaboration of hemolysin, toxic shock syndrome toxin 1, and exfoliative toxin A was inhibited at GML concentrations below those necessary to inhibit growth. Results similar to those for S. aureus were obtained in tests of S. hominis. Escherichia coli growth and Salmonella minnesota growth were unaffected by GML, but an S. minnesota Re mutant was susceptible to growth-inhibitory activity. Endotoxin release into the medium from E. coli cells was also unaffected by GML, but the release or activity of E. coli hemolysin was increased by GML. Streptococcal pyrogenic endotoxin A production by an E. coli clone was not affectd by GML. These studies indicate that GML is effective in blocking or delaying the production of exotoxins by pathogenic gram-positive bacteria.

Glycerides↗
PubMed1992

Internal capsular lesion associated with dizziness.

It has been known that the vestibular system is concerned with feelings of dizziness or vertigo. The vestibulo-thalamic pathway has also been described previously. However, there has been no confirmative report so far regarding the pathway through the internal capsule to the cortex. We have experienced 13 patients with symptoms of dizziness and/or vertigo whose lesions are located only around the internal capsule, mainly at the posterior limb and/or the genu. It is suggestive that fibers with dizziness may pass through a part of the internal capsule, probably through some part of the posterior limb and/or the genu.

Adult↗
PubMed1992

Extracorporeal shockwave lithotripsy of primary intrahepatic stones.

Extracorporeal shockwave lithothripsy (ESWL) was performed in intrahepatic stone patients (n = 18) by Dornier MPL 9,000 with ultrasound guidance. The patients had T-tube (n = 9) or percutaneous transhepatic biliary drainage tube (n = 9). Average treatment session was four and shock-wave numbers were in the range of 3,064 to 12,000 (average 6,288 shocks). Intrahepatic stones were removed completely in 16 patients over a 3 month period by ESWL and combined stone extraction maneuver such as cholangioscopic or interventional radiologic method. Extracorporeal shockwave lithothripsy was very helpful in facilitating extraction of stones in unfavorable locations or located above the severe stricture. In summary, extracorporeal shockwave lithotripsy, followed by percutaneous stone extraction, will provide an improvement in the success rate and duration of treatment required for complete removal of primary hepatolithiasis.

Bile Ducts, Intrahepatic↗
PubMed1991

Streptococcus pyogenes causing toxic-shock-like syndrome and other invasive diseases: clonal diversity and pyrogenic exotoxin expression.

Genetic diversity and relationships among 108 isolates of the bacterium Streptococcus pyogenes recently recovered from patients in the United States with toxic-shock-like syndrome or other invasive diseases were estimated by multilocus enzyme electrophoresis. Thirty-three electrophoretic types (ETs), representing distinctive multilocus clonal genotypes, were identified, but nearly half the disease episodes, including more than two-thirds of the cases of toxic-shock-like syndrome, were caused by strains of two related clones (ET 1 and ET 2). These two clones were also represented by recent pathogenic European isolates. A previous report of a relatively high frequency of expression of exotoxin A among isolates recovered from toxic-shock-like syndrome patients in the United States was confirmed; and the demonstration of this association both within clones and among distantly related clones supports the hypothesis that exotoxin A is a causal factor in pathogenesis of this disease. Near identity of the nucleotide sequences of the exotoxin A structural gene of six isolates of five ETs in diverse phylogenetic lineages was interpreted as evidence that the gene has been horizontally distributed among clones, presumably by bacteriophage-mediated transfer.

Bacterial Proteins↗
PubMed1991

The time course and magnitude of spontaneous recovery of parkinsonism produced by intracarotid administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to monkeys.

We studied rhesus monkeys with hemiparkinsonism or bilateral parkinsonism produced by unilateral or bilateral intracarotid administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Using a standardized clinical rating scale, 4 hemiparkinsonian monkeys showed a 13 to 56% (mean, 36%) spontaneous improvement during an observation period of up to 25 weeks. Generally, recovery leveled off after 14 weeks. Four bilaterally parkinsonian monkeys showed a 5 to 42% (mean, 22%) improvement over a period of up to 30 weeks. Our findings emphasize that spontaneous recovery is a potentially confounding characteristic of this monkey model when used for assessing novel antiparkinsonian therapies.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1991

Oral levodopa dose-response study in MPTP-induced hemiparkinsonian monkeys: assessment with a new rating scale for monkey parkinsonism.

Quantitative measures for the severity of MPTP-induced parkinsonism and response to antiparkinsonian interventions in monkeys have been lacking. We carried out an oral levodopa dose-response study in two rhesus monkeys whose left hemiparkinsonism was induced by intracarotid administration of MPTP. A newly developed clinical rating scale of monkey parkinsonism showed a consistent dose-response relationship for levodopa over the dosage range of 50-3,500 mg/day. Antiparkinsonian effects appeared at 200 mg/day and were optimal at 1,000-2,000 mg/day. Levodopa also reversed rotational behavior, improved movement times for both the impaired and opposite upper limb, and produced dyskinesias at high dosages. Thus, MPTP-induced hemiparkinsonism in monkeys closely resembles the human disease condition, is associated with sensitive response measures, and should prove valuable for assessing novel antiparkinsonian therapies.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1991

Improvement of in vitro fertilization and early embryo development in mice by coculture with human fallopian tube epithelium.

Coculturing one- and two-cell embryos with various cell lines has been shown to overcome species-specific developmental blocks and to improve blastocyst transformation rates. The objective of this study was to assess whether human fallopian tube epithelium organ explants influence in vitro fertilization and subsequent early embryo development in a murine model. Fertilization, blastocyst transformation, and blastocyst expansion and hatching rates were significantly higher in the coculture group when compared with rates for culture in standard media or media conditioned by human tubal explant cultures. The results from conditioned and unconditioned media were not significantly different.

Animals↗
PubMed1991

The effects of electric field-mediated transfer of nonpermeable molecules of meiosis, fertilization, and early embryo development.

Currently there is no simple method of introducing nonpermeable molecules into oocytes or embryos. A technique that would allow direct access to the cytosol with minimal cell damage would be an extremely useful tool in gamete and embryo research. This study investigates the use of electric field-mediated transfer of nonpermeable molecules into mouse oocytes and embryos. Meiosis II stage oocytes, pronuclear stage zygotes, and two-cell embryos were used to determine optimal voltage settings needed for molecular transfer, viability, and blastocyst transformation in culture. Our highest voltage setting (7.0 kV) yielded molecular transfer, viability, and blastocyst transformation rates of 68%, 73%, and 46%, respectively, in two-cell embryos, whereas our lowest setting (3.75 kV) yielded rates of 28%, 90%, and 47%, respectively. Blastocyst transformation rates for control embryos not exposed to the electric field were significantly higher at 69% (p less than 0.01). Meiosis, as assessed by germinal vesicle breakdown, was not affected when compared with controls, 78% versus 83%, respectively. We conclude that electric field-mediated transfer of nonpermeable molecules into oocytes and embryos is a simple, relatively atraumatic technique that can be used to study intraoocyte physiologic characteristics and embryo development.

Animals↗
PubMed1991

Effect of baseline ovarian cysts on in vitro fertilization and gamete intrafallopian transfer cycles.

The presence of ovarian cysts may compromise the success of in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT). We prospectively studied 212 consecutive ovulation induction cycles in 120 patients for IVF and/or GIFT. A baseline cyst was defined as any intraovarian cystic structure greater than or equal to 12 mm noted on ultrasonography before superovulation. Cycle outcomes were compared between patients with cysts (n = 62) versus those with no cysts (n = 150). There were no differences in follicular or luteal phase lengths or amount of human menopausal gonadotropins used. Peak estradiol (E2) levels were significantly lower and cancellation rates significantly higher in the cyst group. For noncanceled cycles, there were no significant differences in peak E2 levels, the mean number of follicles greater than or equal to 12 mm, mature oocytes retrieved, or ova transferred for GIFT or embryos for IVF. The pregnancy rates overall and for noncanceled cycles were not significantly different.

Adult↗
PubMed1991

Fluorinated sugar analogues of potential anti-HIV-1 nucleosides.

In order to obtain agents with therapeutic indices superior to those of AZT, FLT, or D4T, several analogues of anti-HIV-1 nucleosides were synthesized. These include 2',3'-dideoxy-2',3' -difluoro-5-methyluridine (13), its arabino analogue 19, arabino-5-methylcytosine analogue 21, 3'-deoxy-2',3'-didehydro-2' -fluorothymidine (25), 3'-azido-2',3'-dideoxy-2'-fluoro-5-methyluridine (29), 2'-azido-3'-fluoro-2',3'-dideoxy-5-methyluridine (31), and 2'3'-dideoxy-2' -fluoro-5-methyluridine (37). These new nucleosides were screened for their activity against HIV and feline TLV in vitro. None of the compounds showed significant activity. It is interesting to note that such a small modification in the sugar moiety of active anti-HIV nucleosides (i.e., displacement of hydrogen by fluorine) almost completely inactivate the agents.

Animals↗
PubMed1991

Stability of streptococcal pyrogenic exotoxin production with laboratory manipulation of group A streptococci.

Because of reported differences in the production of streptococcal pyrogenic exotoxins by group A strains associated with severe streptococcal infections, the stability of exotoxin production by specific strains was examined by passing group A streptococci on blood agar culture plates daily for 20 days. No changes were detected in either exotoxin genes or in exotoxin production during this time, suggesting that these reported differences are due to other explanations such as differences in the strains collected from various geographic areas or to laboratory methodologic differences.

Bacterial Proteins↗