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Biomedical subjects

T N Lee

Publications and source records attributed to T N Lee.

At least 19 recordsLinked to original sources
PubMed1999

Do antepartum herpes simplex virus cultures predict intrapartum shedding for pregnant women with recurrent disease?

OBJECTIVE: To examine antenatal screening as a predictor of intrapartum shedding of herpes simplex virus (HSV) and to determine its usefulness in guiding the appropriate route of delivery for patients with recurrent HSV in pregnancy. METHODS: A population of 198 pregnant women with a history of recurrent genital HSV were cultured in the last weeks of their pregnancy by specially-trained personnel and intrapartum by their delivering attendants. RESULTS: Of cultures from a total of 906 antenatal visits, 17% were culture positive, with an asymptomatic shedding rate of 3.4%. Asymptomatic shedding occurred in 12.6% of women. Over the 8-week antepartum period, viral culture-positivity rates for each visit ranged from 11% to 19.5%. This provided an expected delivery culture-positivity rate of 15.3%. However, actual intrapartum viral culture positivity occurred in only three of 191 women (1.5%; P < 0.001). Because previous studies have suggested antepartum culture positivity fails to predict intrapartum viral shedding, evaluations, including cultures, as well as predictive values for subsequent culture positivities, were determined under the supervision of an infectious disease specialist. Under these conditions, positive predictive values were 59% when the interval between visits was 2 days, but only 19% when days between visits were >2 (P < 0.0001). No cases of neonatal herpes were seen in this population, although cesarean deliveries were performed in 31% of the patient population, with genital herpes as the indication for 56% of those. CONCLUSIONS: Antepartum serial screening by viral culture is not predictive of an infant's risk of intrapartum viral exposure when conducted at weekly intervals. However, more frequent assessments of patients can be predictive of an infant's exposure risk to HSV; for patients with frequent recurrent disease near term or primary infection in pregnancy, frequent late antepartum screening may be appropriate.

Adolescent↗
PubMed1995

Automated microneutralization: method and comparison with western blot for type-specific detection of herpes simplex antibodies in two pregnant populations.

A novel method for the detection of microneutralization was compared to Western blot for detection of type-specific antibodies to herpes simplex virus in two pregnant patient populations in Vancouver. From an unselected group of women in labor in a tertiary care obstetric hospital (426) and another group of women specially referred for assessment of genital herpes in pregnancy (195) 20 and 88%, respectively, were seropositive for herpes simplex virus type 2 antibodies by Western blot. During the study period, 93 (48%) of the high-risk group were culture positive for HSV-2 and all but one case was verified serologically by Western blot. Therefore, the sensitivity for Western blot in this high seroprevalence group was 99%. The false-negative case had longstanding recurrent infection and on retest was found to be a laboratory error. For microneutralization, type-specificity was especially difficult to distinguish among patients with mixed viral type patterns. Comparing microneutralization to Western blot as the gold standard, sensitivity, specificity, positive and negative predictive values were 84, 78, 97 and 40% respectively, for the referred group and 73, 82, 51 and 92%, respectively, for the unselected group. Poor negative and positive predictive values for the referred group and unselected populations, respectively, demonstrate that microneutralizations are not clinically acceptable for type-specific antibody detection. By contrast, serology by Western blot is very sensitive and apparently highly specific.

Antibodies, Viral↗
PubMed1994

Thalamic neuron theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases.

The Thalamic Neuron Theory (TNT) postulates that the central nervous system (CNS) is involved in all disease processes, as the CNS not only processes incoming physical and chemical information from the periphery, it also sends out physiological commands to the periphery in order to maintain homeostasis for the entire body. Inherent in its capacity to learn and adapt (i.e. to habituate) is the CNS' ability to learn to be sick (pathological habituation) by looking in certain deranged central neural circuitries, leading to chronic disease states. These pathologically habituated states can be reversed by dehabituation through manipulation or modulation of the abnormal neural circuits by physical means (physical neuromodulation) like acupuncture, or chemical means (chemoneuromodulation) such as Chinese medicine, homeopathy or other modern medical techniques in a repetitious manner to mimic the habituation process. Chemoneuromodulation can also be achieved by delivery of minute amounts of pharmacological agents to specific sites in the periphery such as the acupuncture loci. It is hypothesized that humoral and neurotrophic factors and cytokines could be highly effective neuromodulating agents. TNT assumes the blue print for embryological development is embodied in the phylogenetically ancient part of the brain. This primordial master plan, organized in the form of a homunculus, possibly encased in a small nucleus, retains control over the subsequently evolved parts of the brain so that the entire CNS functions like a composite homunculus which controls the physiological functions of the entire body. TNT further postulates that the master homunculus takes the shape of a curled up embryo with its large head buried close to its pelvic region, with its large feet and hands crossed over to the contralateral sides. Neuronal clusters along a neuronal chain in the homunculus represent acupuncture points in the periphery. The neuronal chain itself represents a meridian and Chi is nothing more than the phenomenon of neurotransmissions. Certain new theoretical concepts such as the principles of Adynamic Stat and Bilaterality are also presented. Many difficult to explain clinical observations in modern medicine, Chinese herbal medicine, acupuncture and homeopathy can now be adequately explained using TNT. Based on this model, new therapeutic techniques can be launched to combat a whole host of intractable diseases.

Central Nervous System↗
PubMed1993

Aetiology of AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Analysis of LINE-1 family sequences on a single monkey chromosome.

The structure of LINE-1 (L1Ca) family members present on African green monkey chromosome CAE-19 is compared with that of the entire set of L1Ca sequences present in the monkey genome. The analysis involved annealing of cloned subsegments of monkey L1 family members to DNA-blots containing restriction endonuclease digests of either total monkey liver DNA or DNA isolated from a monkey/mouse somatic cell hybrid carrying the single monkey chromosome. In addition, L1Ca segments cloned from hybrid cell DNA were characterized by restriction endonuclease mapping and hybridization. The data indicate that, taken as a whole, the set of L1Ca sequences on CAE-19 tends to differ in characteristic ways from the set present in the total monkey genome.

Animals↗
PubMed1984

Continuous reorganization leads to extensive polymorphism in a monkey centromeric satellite.

Previously we reported the existence of a highly polymorphic satellite, deca-satellite, in the African green monkey genome; deca-satellite probe anneals to complex sets of repeated restriction endonuclease fragments that differ from individual to individual in the monkey population. Here we present experiments aimed at clarifying the structure and organization of deca-satellite sequences and investigating the mechanisms that generate the polymorphisms. Deca-satellite represents less than 1% of the monkey genome but the percentage varies from one monkey to another. The core sequence 5'-C-C-G-G within the ten base-pair deca-satellite repeat unit is well conserved and the central 5'-C-G is sometimes but not always methylated. Restriction endonuclease analysis with BamHI and EcoRI defines separate satellite domains that have evolved in an independent manner. In situ hybridization shows deca-satellite to be located at the centromeric regions of some but not all monkey chromosomes. This location is independently confirmed by a high frequency, in monkey libraries, of segments containing junctions between deca-satellite and alpha-satellite, the main monkey centromeric satellite. The total number of metaphase chromosomes that show centromeric grains after in situ hybridization with a deca-satellite probe varies from one monkey to another. Moreover, in situ hybridization to endoreduplicated diplochromosomes showed that deca-satellite is occasionally distributed asymmetrically on one or the other of the two pairs of sister chromatids in one diplochromosome. This indicates that major reorganization of the satellite can occur frequently in somatic cells. We discuss several possible mechanisms by which deca-satellite sequences could be either amplified or deleted during a single replicative cycle. Also, on the basis of the marked fluidity of deca-satellite abundance and organization and other well-known attributes of centromeric satellites, we suggest that the existence and maintenance of centromeric satellite rests on the role of the tandem repeats themselves and not on any particular nucleotide sequence, repeat length or organization.

Animals↗
PubMed1981

Recurring defective variants of simian virus 40 containing monkey DNA segments.

Four independently and newly isolated defective variants of simian virus 40 have been characterized. All four are very similar, if not identical, to two previously and independently isolated variants (Wakamiya et al., J. Biol. Chem. 254:3584-3591, 1979; J. Papamatheakis, E. Kuff, E. Winocour, and M. F. Singer, J. Biol. Chem. 255:8919-8927, 1980). The documented similarities include restriction endonuclease maps and the presence of the same monkey DNA segments covalently linked to simian virus 40 DNA sequences. Each of the newly described variants was first detected upon serial passaging of wild-type simian virus 40 at a high multiplicity of infection at 33 degrees C as recently described (M. F. Singer and R. E. Thayer, J. Virol. 35:141-149, 1980). A variety of experiments support the idea that the various isolates were independent and do not reflect inadvertent cross-contamination. Two of the new isolates arose during passage of wild-type strain 777 virus in BSC-1 cells, one during passage of strain 776 in BSC-1 cells, and one during passage of strain 776 in primary African green monkey kidney cells. The two variants obtained after passage of strain 776 were shown to contain a particular recognition site for restriction endonuclease MboII within their simian virus 40 DNA segments, as do the two previous isolates. This site is not present in wild-type strain 776 DNA but is shown here to be present in wild-type strain 777 DNA. The surprising recurrence of closely related variants and particularly the unexpected presence of the endo R.MboII site in variants derived from passaging strain 776 suggest that these variants may arise by mechanisms other than recombination between the initial infecting viral genome and the host DNA.

Animals↗
PubMed1977

Lidocaine injection of auricular points in the treatment of insomnia.

By combining knowledge in modern medicine and traditional Chinese medicine, auricular points were selected for treatment of insomnia. Instead of the placement of needles, injection of small amounts of Lidocaine into these sites was employed. Fifteen out of 16 patients obtained substantial improvement and one patient received moderate improvement. The therapeutic effect was maintained three months after the end of the treatment series. The physiological and clinical implications of this study in terms of modern medicine and traditional Chinese medicine are also discussed.

Acupuncture Therapy↗
PubMed1974

A colinear map relating the simian virus 40 (SV40) DNA segments of six adenovirus-SV40 hybrids to the DNA fragments produced by restriction endonuclease cleavage of SV40 DNA.

The simian virus 40 (SV40) DNA segments present in a series of adenovirus-SV40 hybrids have been mapped with respect to the sites of cleavage of SV40 DNA by restriction endonucleases. Two approaches have been used. First, nucleic acid hybridizations were performed between equimolar quantities of the denatured DNAs of SV40 and each hybrid virus and the radiolabeled transcripts of 11 DNA fragments obtained by cleavage of SV40 DNA by restriction endonuclease from Hemophilus influenzae. Secondly, selected fragments of SV40 DNA produced by the H. influenzae or H. parainfluenzae restriction endonucleases were used to form heteroduplex DNA molecules with adenovirus and adenovirus-SV40 hybrid DNA, which were then analyzed by electron microscopy. The two sets of data were consistent and have permitted alignment of the map of the SV40 segments of the hybrid viruses with the H. influenzae and H. parainfluenzae cleavage maps of SV40. Since cells infected with some of the hybrid viruses contain one or more SV40-specific antigens, the genetic determinants of these antigens could be localized on the cleavage map.

Adenoviridae↗