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Biomedical subjects

D R Lee

Publications and source records attributed to D R Lee.

At least 37 records · Page 2Linked to original sources
PubMed1999

Single dose pharmacodynamics of thioridazine and remoxipride in healthy younger and older volunteers.

Phenothiazines are widely used in older patients, but little experimental work has been carried out in this age group. Two groups of healthy volunteers, a younger group (Y: six males and six females, aged 20-42 years) and an older group (O: six males and eight females, aged 65-77 years) took part in a randomized double-blind three-period crossover study in which they received by mouth single doses of thioridazine (Y: 50 mg; O: 25 mg) remoxipride (Y: 100 mg; O: 50 mg) or placebo. Measures of central nervous system (CNS) and haemodynamic function were carried out before drug administration and at 1.5-h intervals up to 9 h post-dose, and blood samples were collected over a 24-h period. No significant differences in dose-corrected pharmacokinetic variables were found between the two groups. There was evidence of marked CNS depressant effects of thioridazine from both objective and subjective measures. The effects for remoxipride were similar, though generally less marked. After allowance was made for dose, there was little indication of any difference in degree of CNS depression between the two age groups. Haemodynamic measures showed orthostatic reductions in blood pressure with thioridazine which were particularly marked in the older group, who also showed lower compensatory increases in pulse rate. These results indicate potential problems with orthostatic hypotension with thioridazine in older patients. CNS depression may also be a problem, especially in patients with compromised cholinergic function.

Adult↗
PubMed1999

Decrease in the levels of NGF and BDNF in brains of mice fed a tryptophan-deficient diet.

The roles of dietary tryptophan (Trp) were evaluated in regulation of production of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin (NT)-3 in the various brain regions in ddY mice. Feeding the mice a Trp-deficient diet for 2 weeks significantly decreased in the hippocampal level of NGF but not those of BDNF and NT-3, as compared with feeding an adequate Trp diet. The mice fed excess Trp did not have different levels of any of these neurotrophins than in the mice fed an adequate Trp diet. The levels of BDNF in the cerebral cortex were also significantly lower in the mice fed on a Trp-deficient diet, while the levels of NGF and NT-3 in the region were not modulated upon feeding of the diet. The dietary Trp level had no significant effect on the levels of NGF, BDNF, or NT-3 in the entorhinal cortex nor septum of the mice. These results demonstrate that the brain levels of NGF and BDNF are dependent on the dietary content of tryptophan.

Alzheimer Disease↗
PubMed1998

(Ta/Si) multilayer as a wide-bandpass monochromator material.

Specular and non-specular X-ray reflectivity intensities of a (Ta/Si)(60) multilayer sample were measured to characterize its interface structure. Since the multilayer has a good reflectance at its multilayer peaks, its performance as a wide-bandpass monochromator for X-ray scattering experiments of polymers has been tested.

Journal Article↗
PubMed1998

Sequence comparisons of non-human primate HIV-1 coreceptor homologues.

Infection of non-human primate peripheral blood mononuclear cells (PBMCs) in vitro with primary human immunodeficiency virus type 1 (HIV-1) isolates is extremely inefficient and often unattainable. The mechanism of resistance to infection by primary HIV-1 isolates in chimpanzee and baboon PBMCs is unknown. In this study, two HIV-1 coreceptors, CCR5 and CXCR4, were sequenced from chimpanzee and baboon PBMCs to determine if any sequence variations or mutations in these genes could be responsible for resistance to HIV infection. Primers were designed from the human coreceptor sequences and were able to amplify the CCR5 and CXCR4 genes from these non-human primate cells. No 32 base pair deletion (delta32) mutations were found in any of the non-human primate samples tested. CXCR4 sequence analysis showed chimpanzee and baboon share 99.7 and 98% nucleotide sequence homology and 100 and 98.9% amino acid sequence homology, respectively, compared to the human sequence. CCR5 sequence analysis demonstrated that chimpanzee and baboon share 99.6 and 98% nucleotide homology and 100 and 98% amino acid homology, respectively, with the human sequence. These data indicate that no variations in these coreceptor gene sequences exist that can explain the lack of susceptibility to infection with primary HIV-1 isolates in non-human primate PBMCs.

Amino Acid Sequence↗
PubMed1998

Conversion of a human immunodeficiency virus cytotoxic T lymphocyte epitope into a high affinity HLA-Cw3 ligand.

To elucidate the residues important for the binding of peptides to HLA-Cw3, a substitutional analysis of two HLA-Cw*0304-binding peptides was performed. The optimal registry and length for a Cw3-restricted epitope from HIV-1 p24gag was determined to be a nonamer, p24gag 144-152. Substituted analogs of this nonamer peptide revealed that substitutions at position 3 (P3) and the carboxyl-terminal P9 were inhibitory to binding, while certain substitutions at the amino-terminal P1 or P2 increased binding significantly. Substituted analogs of another Cw3-restricted peptide, the Cw3 consensus peptide, which binds to HLA-Cw*0304 with a 1,000-fold higher affinity and with a greater stability than the HIV p24gag nonamer revealed that the P1, P2, P6, and P9 residues play important roles in the ligand's binding to Cw*0304. The incorporation of the amino-terminal P1 and P2 residues from the Cw3 consensus peptide into the HIV p24gag 144-152 peptide created a hybrid peptide with profoundly enhanced affinity for and stability with Cw*0304. Collectively, these findings provide a clear insight into how peptides interact with HLA-Cw3 and how high affinity Cw3 ligands can be constructed.

Antibodies, Monoclonal↗
PubMed1998

Human papillomavirus and disease status following therapy for cervical cancer.

We enrolled 85 patients with invasive cervical cancer and collected cervicovaginal lavage samples at each clinical visit for diagnosis, staging, treatment, and follow-up. Lavage samples were tested by L1 consensus polymerase chain reaction for human papillomavirus (HPV). Results were compared with HPV demonstrated in tumor tissue and the clinical status at time of sample collection. Sensitivity and specificity of the lavage for detection of tumor HPV, determined on the basis of results of tests on lavage samples collected prior to therapy, were found to be 56% and 76.9%, respectively. The proportion of lavage samples detecting tumor HPV decreased significantly with treatment, from 0.54 at diagnosis to 0.03 at complete response (P < .001). Local treatment failure was associated with increased detection of tumor HPV; however, no samples were positive prior to clinically detected treatment failure. These results suggest that cervicovaginal lavage is not an effective sampling method for epidemiological analysis of HPV in cervical tumors.

Adult↗
PubMed1998

Cross-clade inhibition of human immunodeficiency virus type 1 primary isolates by monoclonal anti-CD4.

A murine monoclonal antibody (MAb) with human CD4 specificity was tested for the ability to inhibit primary human immunodeficiency virus type 1 (HIV-1) isolates clades A through E. Human peripheral blood mononuclear cells (PBMC) were used as target cells for infectivity. The HIV-1 primary isolates were examined for the capacity to infect PBMC targets in the presence or absence of the anti-CD4 MAb, designated P1. P1 broadly inhibited clade A, C, D, and E isolates, based on a reduction of HIV-1 p24 antigen concentrations compared with untreated controls. Little to no virus-inhibiting activity was observed with a primary HIV-1 clade B isolate, designated BZ167. Additionally, a second primary clade B isolate was efficiently inhibited from infecting PBMC targets by P1. The data indicate that P1 exhibits group-specific inhibiting activity against non-clade B primary HIV-1 isolates in vitro.

Animals↗
PubMed1998

Expression of DAZ (deleted in azoospermia), DAZL1 (DAZ-like) and protamine-2 in testis and its application for diagnosis of spermatogenesis in non-obstructive azoospermia.

Spermatogenesis is regulated by hormones, local regulatory factors in the testes and specific gene expression of spermatogenic cells in humans. In this study, we have detected the expression of the deleted in azoospermia (DAZ), the DAZ-like autosome (DAZL1), and the protamine-2 genes in spermatogenic cells. Spermatogenesis in 38 male infertility patients was evaluated by the semen analysis and histological examination. Patients were diagnosed as Sertoli cell-only syndrome (n = 20), maturation arrest (n = 6), hypospermatogenesis (n = 6), and obstructive azoospermic patients with normal spermatogenesis (n = 6). After microscopic observation of the wet preparation of the testis tissues, seminiferous tubule contents were used for reverse transcription-polymerase chain reaction (RT-PCR) analysis of DAZ, DAZL1 and protamine-2. In cases with Sertoli-cell only syndrome, we found spermatogenic cells in 30% of patients (6/20) by the wet preparation method. There was no difference between the histology and the wet preparation results in maturation arrest and obstructive azoospermia; however, in one case of hypospermatogenesis, spermatozoa were not detectable by the wet preparation method. Using in-situ hybridization with DAZ and protamine-2 ribonuclear probes, we confirmed spermatogenic cell-specific expression of DAZ (spermatogonia/early spermatocyte) and protamine-2 (spermatid/spermatozoon). DAZ and protamine-2 expression can therefore be considered spermatogenic cell markers and could be useful in molecular diagnosis of spermatogenesis. In 13 patients with spermatozoa under the wet preparation, the expression of DAZ, DAZL1 and protamine-2 was detected in all the preparations. In one wet preparation showing only spermatogonia/spermatocyte, only DAZ and DAZL1 RNA were detected. In 14 wet preparations showing no spermatogenic cells, DAZ, DAZL1 and protamine-2 were not detected except in one preparation where DAZL1 expression was detected. In 10 wet preparations representing spermatogonia/spermatocyte to spermatids, but showing no spermaozoa, DAZ and DAZL1 were detected in eight and nine preparations respectively, and protamine-2 was detected in six preparations. These results of gene expression were similar to the wet preparation results. RT-PCR for DAZ, DAZL1 and protamine-2 was informative for the existence of germ cells, germ cell physiology and differentiation. From these results, we suggest that the analysis of DAZ, DAZL1 and protamine-2 expression by RT-PCR and wet preparation might offer a better method for finding the spermatogenic cells compared to the histological method.

Actins↗
PubMed1998

Detection of human papillomavirus in archival tissues. Comparison of in situ hybridization and polymerase chain reaction.

Formalin-fixed, paraffin-embedded tissues in pathology archives are an important resource for molecular epidemiology studies. Use of these tissues requires that assays be optimized to account for inevitable variations in tissue fixation and processing that occur in the performance of routine histology. We compared results of colorimetric in situ hybridization (ISH) to L1 consensus polymerase chain reaction (PCR) for detection and typing of human papillomavirus (HPV) in 180 blocks of archival tissues (up to 9 years in storage) from cervical cancer patients. Fifteen samples could not be amplified by PCR, but assays were concordant in 75.1% (124/165) of samples that could be analyzed by both methods. Similar numbers of ISH+/PCR- (23) and ISH-/PCR+ (18) cases were found. Eight of the 18 ISH-/PCR+ cases were attributable to PCR detection of HPV types not included in the ISH assay. This degree of concordance required individual optimization of assay conditions for each block. ISH and PCR assays for HPV yield complementary results, and both can be successfully applied to archival tissues.

Female↗
PubMed1997

Biochemical and functional characterization of soluble multivalent MHC L(d)/Fc gamma 1 and L(d)/Fc mu chimeric proteins loaded with specific peptides.

Central to the specificity of the immune system is the interaction between the T cell receptor and the major histocompatibility complex (MHC)-peptide ligand complex. To better understand the nature of this interaction, and to investigate possible avenues for specific therapeutic intervention, we have produced soluble recombinant molecules that can modulate antigen-specific T cells. Our approach involved the construction of recombinant murine genes composed of the MHC class I gene H-2L(d) and the Fc portion of immunoglobulin (Ig) heavy chain genes mu or gamma1. Stable transfectants of these L(d)/Fc gamma1 and L(d)/Fc mu genes generated correctly spliced transcripts and were capable of secreting chimeric protein. Immunoprecipitation analyses demonstrated the presence of chimeric L(d)/ Fc gamma1 and L(d)/Fc mu monomers of approximately 69 kDa and 90 kDa, respectively, as well as chimeric dimers under nonreducing conditions. The capacity of L(d)/Ig molecules to bind specific peptide ligands was demonstrated using radiolabeled peptides or with monoclonal reagents that specifically identify peptide-induced conformational changes in the L(d) ligand binding site. Soluble divalent L(d)/Fc gamma1 molecules were loaded with the murine cytomegalovirus-derived peptide and other L(d)-specific peptide ligands and subsequently isolated and purified. Peptide-loaded L(d)/Fc gamma1 molecules were capable of inhibiting the response of class I-restricted T cells in vitro in a peptide-specific fashion. The development of soluble multivalent chimeric proteins that possess unique properties of both the MHC class I and Ig molecules provides a valuable reagent for the study of potential mechanisms of in vitro and in vivo immune modulation.

Animals↗
PubMed1997

Association of human papillomavirus type 16 integration in the E2 gene with poor disease-free survival from cervical cancer.

To determine the clinical relevance of human papillomavirus (HPV) integration and E2 function suggested by in vitro studies, we investigated 50 patients with HPV 16-positive primary cervical carcinoma (stage Ib-IV) diagnosed and treated at one institution. The physical state of HPV was determined by colorimetric in situ hybridization and was not found to vary by stage. Overall, 62% of tumors had integrated HPV, 16% had episomal and 22% had both integrated and episomal. The E1/E2 region was evaluated by 8 separate polymerase chain reactions, which resulted in overlapping products. There was no significant variation in ability to amplify the E1/E2 region with stage. E1/E2 amplification correlated with physical state. Nearly all tumors with episomal or mixed HPV 16 DNA amplified all 8 E1/E2 fragments. Half of the tumors with integrated HPV 16 DNA failed to amplify one or more E1/E2 fragments. Disruptions were most frequent in the E2 region. For all 46 patients receiving curative therapy, the Kaplan-Meier estimate of disease-free survival was determined for those whose primary tumors had amplifiable E2 compared with those lacking one or more E2 DNA fragments. Disruption of E2 was associated with significantly shortened disease-free survival.

Adenocarcinoma↗
PubMed1997

Induction of acrosome reaction in human spermatozoa accelerates the time of pronucleus formation of hamster oocytes after intracytoplasmic sperm injection.

OBJECTIVE: To assess the relationship between the incidence of acrosome reaction (AR) and the timing of pronucleus (PN) formation after intracytoplasmic sperm injection (ICSI). DESIGN: Prospective study. SETTING: Infertility Research Center, Jeil Women's Hospital. MAIN OUTCOME MEASURE(S): Human semen obtained from fertile donors was prepared by one of the following methods: washing only (washed control); Percoll gradient; pentoxifylline; human follicular fluid (FF); pentoxifylline + FF; or platelet-activating factor (PAF) treatment. The AR of each group was assessed by fluorescein isothiocyanate-conjugated Pisum sativum agglutinin or Arachis hypogea agglutinin. Spermatozoa of washed control, pentoxifylline + FF, and PAF treated groups, with significantly higher AR rate than others, were injected into mature hamster oocytes. Spermatozoon-injected oocytes were cultured for 6, 9, 12, or 15 hours. Then they were stained with Toluidine blue for PN formation examination under a light microscope. RESULT(S): Acrosome reaction rates of washed control, Percoll gradient, pentoxifylline, FF, pentoxifylline + FF, and PAF treated groups were 10.5% +/- 2.6%, 10.3% +/- 1.7%, 16.4% +/- 1.8%, 24.8% +/- 5.6%, 28.4% +/- 3.8%, and 33.3% +/- 5.2%, respectively. Pronuclear formation rate in washed control, pentoxifylline + FF, and PAF treated groups were 5.6% (3/54), 19.0% (11/58), and 18.9% (10/53) at 6 hours; 32.7% (18/55), 51.8% (29/56), and 57.4% (31/54) at 9 hours; 36.1% (22/61), 53.6% (30/56), and 50.0% (27/54) at 12 hours; and 47.2% (25/53), 64.8% (35/54), 53.6% (30/56) at 15 hours after ICSI. Pronuclear formation rate was significantly higher in pentoxifylline + FF, and PAF treated groups than that in the washed control group at 6 and 9 hours after ICSI. CONCLUSION(S): Pronuclear formation of oocytes takes place faster on those that were injected with acrosome-reacted spermatozoon than those injected with acrosome-intact spermatozoon. It could be concluded that induction of the AR of spermatozoa accelerates the time of PN formation and early development of the embryo in ICSI.

Acrosome↗
PubMed1997

The supplementation of culture medium with protease improves the hatching rate of mouse embryos.

Mammalian embryos are known to exhibit delayed development and have lower hatching rates in vitro than in vivo because of inadequate culture condition. These discrepancies may be due to a deficiency of the paracrine factors and proteolytic enzymes which exist in the oviduct and uterus. In order to evaluate the effects of proteases on embryonic development and hatching, 2-cell mouse embryos were cultured for 72 h with or without proteases. The addition of 1.0 microg/ml pronase (PE) and/or 0.1 microg/ml proteinase K (PK) did not affect embryonic development up to the blastocyst stage (94.1% versus 88.2%; 92.2% versus 90.2%, respectively) but significantly increased the hatching rate (60.4% versus 39.2%, 71.8% versus 35.3%, respectively). However, the addition of alpha-chymotrypsin (Chymo) was detrimental to embryonic development and hatching. Changes in the structure of the zona pellucida (ZP) structure of embryos which had been cultured in human tubal fluid (HTF) medium with PE and PK were assessed by fluorescein isothiocyanate-conjugated (FITC)-casein. Embryos cultured in HTF-PE and PK were not stained with FITC-casein. When these embryos were cultured within oviducts, their perivitelline space (PVS) became strongly stained with FITC-casein which was easily removed by phosphate-buffered saline washing. This suggests that PE and PK altered the structure of the ZP. We suggest that the addition of PE and PK to culture media may accelerate the hatching of embryo, by structurally altering the ZP and PVS. This may provide a valuable and effective assisted hatching technique for human in-vitro fertilization-embryo transfer.

Animals↗
PubMed1997

Spontaneous anaplastic large cell lymphoma in a chimpanzee: a clinicopathological and immunohistochemical study.

An anaplastic large cell lymphoma with disseminated abdominal metastases was diagnosed in a 35-year-old male chimpanzee. Clinically, the animal displayed lethargy, weight loss, ascites, and abdominal distention. Imaging studies showed several large abdominal masses. At necropsy, variably sized masses of neoplastic mesenteric lymph nodes that encompassed several intestinal loops were present throughout the abdomen. The largest mass measured 9 x 5 cm and had cauliflower-like protrusions into the jejunal lumen. The entire abdominal cavity was covered by a sheet of neoplastic tissue. Histopathologically, the tumor consisted of solid sheets of proliferating lymphoid cells forming a cohesive growth that filled the lymph node sinuses. The tumor had invaded the intestinal wall. Anaplastic large cell lymphoma was diagnosed from immunohistochemistry findings on the basis of positive reaction to the CD3 and CD30 markers and negative reaction to the CD20 marker. Serologic analysis revealed positive titers for Epstein-Barr, cytomegalo-, and varicella-zoster viruses. Both serologic and virologic studies showed no evidence of detectable retroviral infection. This type of tumor has not been reported before in the chimpanzee.

Animals↗
PubMed1997

Human papillomavirus type in anal epithelial lesions is influenced by human immunodeficiency virus.

BACKGROUND AND OBJECTIVE: Infection with human immunodeficiency virus (HIV) increases the risk for human papillomavirus (HPV)-associated genital neoplasia. Human immunodeficiency virus-infected patients also have higher rates of treatment failure and more rapid neoplastic progression. Impaired immune function does not entirely explain these clinical observations. This pilot project was designed to investigate the hypothesis that HIV infection is associated with changes in HPV type and integration within anogenital lesions that could explain the increased risk of neoplastic progression. METHODS: Anal neoplastic lesions from patients with and without HIV infection were analyzed for the presence, type, and integration status of HPV by colorimetric in situ hybridization. Tissue localization of HIV was evaluated by p24 immunohistochemistry and HIV-1 DNA polymerase chain reaction. Results for matched histology were compared for the two patient groups. RESULTS: For all lesions, the presence of high-risk HPV types and multiple HPV types was strongly associated with HIV infection (P = .003 and .0003, respectively). For lesions with matched histology there was no association of HPV integration with HIV status. Tissue localization of HIV did not significantly influence HPV type or integration. CONCLUSIONS: The presence of high-risk HPV types and multiple types within low-grade lesions may explain the increased risk of neoplastic progression in HIV patients. Colocalization of HIV and HPV does not appear to be required for this effect. There is no evidence that HPV integration is influenced by HIV infection.

Adolescent↗
PubMed1996

Titration of a vaccine stock preparation of human immunodeficiency virus type 1SF2 in cultured lymphocytes and in chimpanzees.

A large stock preparation of the HIV-1SF2 isolate has been derived after serial passage in human peripheral blood mononuclear cells (PBMCs). This viral stock has a titer of 10(4.9) TCID50 in human PBMCs and 10(4.2) TCID50 in chimpanzee PBMCs. By inoculation into animals the 50% chimpanzee infectious dose titer was found to be about 10(2.3). Virus isolation from animals was achieved on most occasions within 1-4 weeks after inoculation and then became transient. Viral RNA and DNA PCR analyses confirmed the virus infection of the chimpanzees. Anti-HIV antibody levels in the inoculated animals ranged from 1:400 to 1:6400 as measured by ELISA. About 680 vials of this stock preparation, frozen at -190 degrees C, are available for future studies of vaccines and antiviral therapies.

AIDS Vaccines↗
PubMed1996

Studies of tum- peptide analogs define an alternative anchor that can be utilized by Ld ligands lacking the consensus P2 anchor.

To determine how peptides that lack a consensus binding motif interact with class I molecules, we have studied the binding of the tumor-associated tum- P91A 14-22 (tum-) peptide to Ld. Previously, a proline at position 2 (P2) and a hydrophobic residue at P9 had been defined as anchors for Ld ligands. However, the tum- peptide lacks the P2 proline anchor. To compare how peptides with and without the P2 proline anchor bind to Ld, we analyzed the binding of monosubstituted analogues of the murine cytomegalovirus (MCMV) pp89 168-176 and the tum- peptides to Ld. As expected, the binding of both peptides was inhibited by substitutions at P9, the carboxyl-terminal anchor. As also predicted, the MCMV peptide was found to be dependent upon its P2 proline for binding to Ld. By contrast, the binding of the tum- peptide to Ld is dependent primarily on a P8 aspartate residue. Interestingly, the p2Ca peptide that is immunodominant in allorecognition of Ld also lacks the P2 proline anchor and has been shown to depend on residues near the carboxyl terminus for binding to Ld. Furthermore, both the p2Ca and the tum- peptides can bind to Ld as octamers. These combined studies suggest that there are at least two alternative manners by which peptides can bind to Ld. Although most Ld ligands bind using a P2 proline anchor, the tum- and p2Ca peptides bind using alternative anchors in the carboxyl-terminal region.

Amino Acid Sequence↗