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Verweij BH, Muizelaar JP, Vinas FC, Peterson PL, Xiong Y, Lee CP. Improvement in mitochondrial dysfunction as a new surrogate efficiency measure for preclinical trials: dose-response and time-window profiles for administration of the calcium channel blocker Ziconotide in experimental brain injury. J Neurosurg 2000; 93:829-34. [PMID: 11059665 DOI: 10.3171/jns.2000.93.5.0829] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Determining the efficacy of a drug used in experimental traumatic brain injury (TBI) requires the use of one or more outcome measures such as decreased mortality or fewer neurological and neuropsychological deficits. Unfortunately, outcomes in these test batteries have a fairly large variability, requiring relatively large sample sizes, and administration of the tests themselves is also very time consuming. The authors previously demonstrated that experimental TBI and human TBI induce mitochondrial dysfunction. Because mitochondrial dysfunction is easy to assess compared with neurobehavioral endpoints, it might prove useful as an outcome measure to establish therapeutic time windows and dose-response curves in preclinical drug testing. This idea was tested in a model of TBI in rats. METHODS Animals treated with the selective N-type voltage-sensitive calcium channel blocker Ziconotide (also known as SNX-111 and CI-1009) after cortical impact displayed significant improvement in brain mitochondrial function. When a single intravenous bolus injection of 4 mg/kg Ziconotide was given at different time intervals, ranging from 15 minutes before injury to 10 hours after injury, mitochondrial function was improved at all time points, but more so between 2 and 6 hours postinjury. The authors evaluated the effects on mitochondrial function of Ziconotide at different doses by administering 0.5 to 6 mg/kg as a single bolus injection 4 hours after injury, and found 4 mg/kg to be the optimum dose. CONCLUSIONS The authors established these time-window profiles and dose-response curves on the basis of mitochondrial outcome measures in a total of 42 rats because there were such low standard deviations in these tests. Establishing similar time-window profiles and dose-response curves by using neurobehavioral endpoints would have required using 114 rats in much more elaborate experiments.
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Verweij BH, Muizelaar JP, Vinas FC, Peterson PL, Xiong Y, Lee CP. Impaired cerebral mitochondrial function after traumatic brain injury in humans. J Neurosurg 2000; 93:815-20. [PMID: 11059663 DOI: 10.3171/jns.2000.93.5.0815] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Oxygen supply to the brain is often insufficient after traumatic brain injury (TBI), and this results in decreased energy production (adenosine triphosphate [ATP]) with consequent neuronal cell death. It is obviously important to restore oxygen delivery after TBI; however, increasing oxygen delivery alone may not improve ATP production if the patient's mitochondria (the source of ATP) are impaired. Traumatic brain injury has been shown to impair mitochondrial function in animals; however, no human studies have been previously reported. METHODS Using tissue fractionation procedures, living mitochondria derived from therapeutically removed brain tissue were analyzed in 16 patients with head injury (Glasgow Coma Scale Scores 3-14) and two patients without head injury. Results revealed that in head-injured patients mitochondrial function was impaired, with subsequent decreased ATP production. CONCLUSIONS Decreased oxygen metabolism due to mitochondrial dysfunction must be taken into account when clinically defining ischemia and interpreting oxygen measurements such as jugular venous oxygen saturation, arteriovenous difference in oxygen content, direct tissue oxygen tension, and cerebral blood oxygen content determined using near-infrared spectroscopy. Restoring mitochondrial function might be as important as maintaining oxygen delivery.
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Lam YH, Lee CP, Tang MH, Lau E. Thermocoagulation for selective reduction of conjoined twins at 12 weeks of gestation. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2000; 16:267-270. [PMID: 11169295 DOI: 10.1046/j.1469-0705.2000.00230.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Conjoined twins occur rarely. Most of the prenatally diagnosed cases are terminated either because of extensive organ sharing or because of the presence of major structural abnormalities. We present a case of omphalopagus conjoined twins diagnosed at 10 weeks of gestation with selective reduction performed at 12 weeks. The twins were conjoined at the umbilicus with vascular communication demonstrated at the conjunction. Twin A was normal but twin B was growth restricted and hydropic. Thermocoagulation of twin B was performed at 12 weeks by passing an insulated electric wire through a 18-gauge needle placed close to the fetal heart. Reassessment at 15 weeks showed that twin A was growing normally with a small dead twin B attached at its umbilicus. Twin B was subsequently sloughed off from this attachment and could be seen lying free in the amniotic cavity at 17 weeks. Twin A was delivered at term and was healthy. A small scar could be seen just above the umbilical cord insertion. This case represents the first antenatal example of selective reduction of conjoined twins by thermocoagulation.
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Lam YH, Tang MH, Lee CP, Sin SY, Tang R, Wong HS, Wong SF. Acceptability of serum screening as an alternative to cytogenetic diagnosis of down syndrome among women 35 years or older in Hong Kong. Prenat Diagn 2000; 20:487-90. [PMID: 10861714 DOI: 10.1002/1097-0223(200006)20:6<487::aid-pd853>3.0.co;2-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The addition of second trimester serum markers to maternal age increases the efficacy of screening for Down syndrome by maternal age alone. Among women aged 35 years or older, serum screening makes a large proportion of amniocentesis unnecessary. However, there are ethical and medicolegal concerns about serum screening in 'old' women, largely because some of the pregnancies affected by Down syndrome and other chromosomal abnormalities may not be detected. We investigated the acceptability of serum screening in women aged 35 years or older when it was offered as an alternative to prenatal cytogenetic diagnosis after detailed counselling. Women referred for prenatal diagnosis of Down syndrome because of advanced maternal age were given the options of cytogenetic diagnosis by chorionic villus sampling (CVS) or amniocentesis. As an alternative, they could choose to undergo second trimester serum human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) screening first before deciding on whether to undergo amniocentesis. Between January 1997 and October 1999, 3419 subjects were recruited. 1807 women (52. 9%) chose to undergo serum screening, 1516 women (44.3%) chose to have amniocentesis and 96 women chose to have CVS (2.8%). The proportion of women who chose serum screening rose steadily from 38. 8% in the year of 1997 to 63.4% in 1999. Significantly fewer Chinese women chose serum screening than non-Chinese. The decision as to whether to undergo an invasive diagnostic procedure or to be content with the relatively safer but less accurate screening test varies, being affected by the women's background and culture.
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Chen BH, Lee CP, Chao MC. Coexistent insulin dependent diabetes mellitus and hyperthyroidism in a patient with Down's syndrome. Kaohsiung J Med Sci 2000; 16:210-3. [PMID: 10933753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
The prevalence of thyroid disease is increased in Down's syndrome. Compared with adults, thyroid dysfunction in children with Down's syndrome is less frequently reported. Insulin dependent diabetes mellitus is also uncommon in Down's syndrome children. Coexistent insulin dependent diabetes mellitus and hyperthyroidism in Down's syndrome was only reported once previously in literature. We report an 8-year-old girl with Down's syndrome that had polyuria, polydipsia, abdominal pain and urinary incontinence one and half a month prior to admission. Physical examination revealed typical face of Mongolism and tachycardia. Thyroid glands were not palpable. Laboratory data revealed diabetic ketoacidosis with plasma glucose: 860 mg/dl. She had thyroid hyperfunction with TSH: < 0.1 microU/ml, T3: 219.7 ng/dl, T4: 15 micrograms/dl. Thyroid autoimmune antibodies were also increased. There was markedly increased radiotracer uptake in the bilateral thyroid glands in Tc-99 thyroid scan. We suggest that Down's syndrome children with insulin dependent diabetes mellitus should be evaluated carefully for thyroid function and autoimmune disease.
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Xiong Y, Peterson PL, Lee CP. Effect of N-acetylcysteine on mitochondrial function following traumatic brain injury in rats. J Neurotrauma 1999; 16:1067-82. [PMID: 10595823 DOI: 10.1089/neu.1999.16.1067] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Efficacy of N-acetylcysteine (NAC) in traumatic brain injury (TBI)-induced mitochondrial dysfunction was evaluated following controlled cortical impact injury in rats. Respiratory function and calcium transport of rat forebrain mitochondria from injured and uninjured hemispheres were examined. NAC significantly restored mitochondrial electron transfer, energy coupling capacity, calcium uptake activity and reduced calcium content absorbed to brain mitochondrial membranes when examined 12 h post-TBI if NAC was administered i.p. 5 min before injury or 30 min or 1 h postinjury. Glutathione (reduced form, GSH) levels in brain tissues were decreased at all time points examined over a 14-day observation period, while mitochondrial GSH levels significantly decreased only at 3 days and 14 days following TBI. NAC treatment given within 1 h greatly restored brain GSH levels from 1 h to 14 days and mitochondrial GSH levels from 12 h to 14 days post-TBI. NAC did not show protective effects when given 2 h postinjury. Our data indicate that NAC administered postinjury at an early stage can effectively restore TBI-induced mitochondrial dysfunction and the protective effect of NAC may be related to its restoration of GSH levels in the brain.
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Stenberg P, Luthman K, Ellens H, Lee CP, Smith PL, Lago A, Elliott JD, Artursson P. Prediction of the intestinal absorption of endothelin receptor antagonists using three theoretical methods of increasing complexity. Pharm Res 1999; 16:1520-6. [PMID: 10554092 DOI: 10.1023/a:1015092201811] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE Three new computational strategies have been evaluated for their ability to predict intestinal membrane permeability to a series of endothelin receptor antagonists. METHODS The three methods were evaluated using a set of ten nonpeptide endothelin receptor antagonists. The simplest method, "the rule of five", is based on 2D parameters such as the number of potential hydrogen bonds, molecular weight and calculated lipophilicity. A method based on molecular mechanics calculations is used to calculate 3D parameters such as polar and non-polar parts of the molecular surface area. The third method uses quantum mechanics to calculate molecular properties related to the valence region. RESULTS Descriptors derived by the latter two methods correlated well with permeability coefficients of the endothelin receptor antagonists. On the other hand, the rule of five failed to discriminate between drugs with high and low permeability. CONCLUSIONS Molecular surface descriptors and descriptors derived from quantum mechanics are potentially useful for the virtual screening of the permeability of the intestinal membrane to endothelin receptor antagonists.
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Lam YH, Tang MH, Lee CP, Tse HY. Echogenic bowel in fetuses with homozygous alpha-thalassemia-1 in the first and second trimesters. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 1999; 14:180-182. [PMID: 10550877 DOI: 10.1046/j.1469-0705.1999.14030180.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE Fetal echogenic bowel has been observed in fetuses with meconium peritonitis, cystic fibrosis, aneuploidy, congenital viral infection and intrauterine growth restriction. The pathogenesis of echogenic bowel is unknown, but it may be attributed to bowel ischemia. Fetuses affected by homozygous alpha-thalassemia-1 are severely anemic and hypoxic. We investigated the incidence of echogenic bowel in these hypoxic fetuses in the first and second trimesters. DESIGN Prospective observational study. SUBJECTS Women referred for the prenatal diagnosis of homozygous alpha-thalassemia-1 before 24 weeks' gestation. METHODS All subjects had one or more abdominal and/or vaginal ultrasound examination between 12 and 24 weeks' gestation. Echogenic bowel was diagnosed if the bowel appeared either isoechogenic or more echogenic than the bone. RESULTS Between March 1997 and July 1998, 126 pregnancies were studied. Thirty-six fetuses were confirmed to be affected by homozygous alpha-thalassemia-1, and 11 of them (31%, 95% CI 16-48%) had echogenic bowel. These observations were made before the invasive test results were available. None of the fetuses unaffected by homozygous alpha-thalassemia-1 had echogenic bowel. CONCLUSION There is a strong association between homozygous alpha-thalassemia-1 and echogenic bowel. The pathogenesis is unknown. Speculations include bowel hypoperistalsis or bowel wall edema due to severe anemia and hypoxia.
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Wei CY, Hwang JJ, Chu CH, Lee CP. Detection and identification of Mycobacterium tuberculosis by nested PCR assays in cerebrospinal fluid samples from patients with suspected tuberculous meningitis. Kaohsiung J Med Sci 1999; 15:475-83. [PMID: 10518364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
We used the nested polymerase chain reaction (PCR) assays developed previously to detect and identify Mycobacterium tuberculosis (M. tuberculosis) in the cerebrospinal fluid (CSF) samples from patients with suspected tuberculous meningitis and non-tuberculous patients. Our nested PCR assays target the multi-copy IS6110 insertion element and the single-copy mtp40 genomic DNA of M. tuberculosis. These assays, when used in combination, allowed us to detect a very low number of M. tuberculosis in the CSF samples, which otherwise would be undetectable by the culture method, and to distinguish M. tuberculosis from M. bovis. We applied these nested PCR assays to analyze eleven CSF samples. Among these, five of them were from patients with suspected tuberculous meningitis but all except one were culture negative. Our results of PCR assays show that three of these five are M. tuberculosis positive, one of which is M. bovis positive, and only one is M. tuberculosis negative. The other six CSF samples were from the clinically diagnosed non-tuberculous patients. Surprisingly, two of these so called non-tuberculous patients, a subarachnoid hemorrhage (SAH) and the syndrome of inappropriate antidiuretic hormone secretion (SIADH), were shown M. tuberculosis positive. This finding supports a long-standing argument that tuberculous meningitis is one of the causes of these neurological diseases. These nested PCR assays thus provide the neurologists with an important adjunct, in addition to the patient's clinical presentation and laboratory data, for the diagnosis of tuberculous meningitis.
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Wei CY, Lee CN, Chu CH, Hwang JJ, Lee CP. Determination of the sensitivity and specificity of PCR assays using different target dnas for the detection of Mycobacterium tuberculosis. Kaohsiung J Med Sci 1999; 15:396-405. [PMID: 10465921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
To establish a sensitive, specific and reproducible PCR assay for the detection of Mycobacterium tuberculosis, we evaluated three target DNAs: IS6110, 65 kDa heat shock protein gene; and mtp40 genomic fragment. We purified genomic DNA from 15 mycobacterial strains including four M. tuberculosis isolates, four M. bovis BCG isolates, and one of each for M. fortuitum, M. avium, M. intracellulare, M. szulgai, M. scrofulaceum, M. chelonei, and M. gordonae from the culture and used them as the template DNA. We studied 3 primer sets for IS6110, 2 primer sets for 65 kDa, and 3 primer sets for mtp40. Depending on the assay, these primer sets were used in the single-step PCR and/or nested PCR. The PCR assay targeting the 65 kDa protein gene could detect all of the tested mycobacterial strains, whereas targeting the IS6110 sequence resulted in detection of only M. tuberculosis and M. bovis BCG. Furthermore, targeting the mtp40 genomic fragment could be used to distinguish M. tuberculosis from M. bovis BCG. Using a nested PCR assay with primer sets specifically targeting the IS6110 or 65 kDa, we have been able to detect single copy M. tuberculosis genomic DNA. When the mtp40 genomic fragment was used as the target DNA, the sensitivity of detection was 10 copies of M. tuberculosis genomic DNA. This assay was demonstrated to have good sensitivity and specificity for detection and discrimination of mycobacterial species, and could be used in analyzing the clinical samples with low copy number infections such as the cerebrospinal fluid from the patient with tuberculous meningitis.
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Lin IJ, Che MJ, Yeh A, Hwang JJ, Wei CY, Tsao WL, Lee CP. Comparison of the sensitivity and specificity of an automatic ligase chain reaction assay system with a one-step polymerase chain reaction assay in the diagnosis of Mycobacterium tuberculosis complex. CHANGGENG YI XUE ZA ZHI 1999; 22:204-11. [PMID: 10493024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
BACKGROUND Polymerase chain reaction (PCR) and ligase chain reaction (LCR) are two nucleic acid amplification-based molecular methods. The former has been used widely in the identification of Mycobacterium tuberculosis (M. tuberculosis). In contrast, the LCR assay which was recently introduced is not well known in our medical communities in Taiwan. To determine which method is more reliable and suitable for the identification of M. tuberculosis in our clinics, we compared the sensitivity and specificity of these two methods. METHODS An automatic LCR assay system and a manual one-step PCR assay were studied in a side by side comparison of their performance in detection of M. tuberculosis. The automatic LCR system uses the single copy antigen protein b (Pab) gene and the manual one-step PCR assay uses the multi-copy IS6110 insertion element as the target DNA; both target DNA sequences are found specifically in M. tuberculosis complex. RESULTS Both assays detected two of the M. tuberculosis complex strains, M. tuberculosis and M. bovis, but not other mycobacterial strains. In addition, both methods, which were based on different amplification principles, showed compatible sensitivity; as low as 10 and 100 copies of M. tuberculosis genomes were detected by the LCR and PCR assays, respectively. When the template DNA was less than 1000 copies, however, the automatic LCR assay system showed a lower reproducibility than that of the one-step PCR assay. CONCLUSION Our results suggest that in addition to the PCR assay, the LCR assay is a useful method for the molecular identification of M. tuberculosis complex strains.
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Abstract
BACKGROUND New criteria for diagnosing ischemic response to treadmill exercise testing (TET) have continuously been proposed. Simultaneous comparison of test performances according to these criteria is likely contributory to interpreting TET and needs to be updated time after time. This study was conducted to accomplish this end. METHODS A comparison of test performances of various TET variables for a cohort of 107 clinical normals and 139 angiographic patients with normal resting electrocardiograms was performed. Angiographic references included enumeration of diseased coronary vessels, Gensini's and Duke's coronary scores, left ventricular wall motion score and ejection fraction at rest. RESULTS The ST-segment-related variables (depression, integral, and heart-rate-adjusted slope or index) outdid non-ST-segment variables (changes in R amplitude, the Athens QRS score, peak exercise blood pressure increment and recovery pressure ratios; most P < 0.05) in diagnosing coronary artery disease. Among them the heart-rate-adjusted ST-segment depression performed still better. This trend was not evident in identifying left main and three-vessel disease. However, correlation to the coronary scores favored the ST-segment-related criteria (r = 0.18-0.39, P < 0.05 to P < 0.001 versus r = 0.05-0.23, NS to P < 0.01) for evaluating severity of coronary artery disease. CONCLUSIONS For patients with normal resting electrocardiograms, the adjustment of ST-segment depression for heart rate is valuable for evaluating coronary artery disease.
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Lam YH, Tang MH, Lee CP, Tse HY. Nuchal translucency in fetuses affected by homozygous alpha-thalassemia-1 at 12-13 weeks of gestation. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 1999; 13:238-240. [PMID: 10341400 DOI: 10.1046/j.1469-0705.1999.13040238.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE Fetuses affected by homozygous alpha-thalassemia-1 are anemic in the first trimester. We studied their nuchal translucency (NT) measurements at 12-13 weeks of gestation. METHODS Nuchal translucency was measured prospectively in fetuses at risk of homozygous alpha-thalassemia-1. Measurements of those fetuses subsequently confirmed to be affected by homozygous alpha-thalassemia-1 but with a normal karyotype were compared to those of 440 controls. The controls were from the general obstetric population who had NT measurements at 12 or 13 weeks with known normal outcome. All the NT measurements were expressed as multiples of the median (MoM) for the gestational day. RESULTS Between 1996 and 1998, 94 at-risk pregnancies were studied. Of these, 32 were subsequently confirmed to be affected by homozygous alpha-thalassemia-1. Chromosome study was not carried out in three cases and these were excluded from the analysis. Nuchal translucency MoMs for cases and controls were found to fit a log Gaussian distribution. The log means (standard deviation) for case and control NT MoM were 0.075 (0.156) and -0.0019 (0.091), respectively. The median NT MoM (95% CI) for cases was 1.19 (1.08-1.62) and was significantly higher than that of the controls (p < 0.001). However, there was extensive overlap of NT between cases and controls. CONCLUSION Overall, there was a 19% increase in NT MoM in fetuses affected by homozygous alpha-thalassemia-1. This represents a difference of only 0.3-0.4 mm, which is clinically insignificant. This finding indirectly suggests that the increased NT in trisomic fetuses cannot be explained by fetal anemia. Conversely, the presence of increased NT in a fetus at risk of homozygous alpha-thalassemia-1 should alert one to the possibility of chromosomal abnormality rather than being attributed to fetal anemia.
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Lam YH, Eik-Nes SH, Tang MH, Lee CP, Nicholls JM. Prenatal sonographic features of spondylocostal dysostosis and diaphragmatic hernia in the first trimester. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 1999; 13:213-215. [PMID: 10204217 DOI: 10.1046/j.1469-0705.1999.13030213.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Spondylocostal dysostosis is a congenital disorder characterized by multiple malformations of the vertebrae and ribs. We describe the sonographic features of an affected fetus at 12 and 14 weeks of gestation. The fetus had thoracic scoliosis, multiple vertebral and rib malformations and a grossly dilated stomach that had herniated into the chest through a left-sided diaphragmatic hernia. The stomach spanned the whole length of the fetal trunk.
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Lam YH, Tang MH, Lee CP, Tse HY. Prenatal ultrasonographic prediction of homozygous type 1 alpha-thalassemia at 12 to 13 weeks of gestation. Am J Obstet Gynecol 1999; 180:148-50. [PMID: 9914594 DOI: 10.1016/s0002-9378(99)70165-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We determined the feasibility of prenatal prediction of type 1 homozygous alpha-thalassemia at 12 to 13 weeks of gestation by either abdominal or vaginal (or both) ultrasonographic examination to measure the fetal cardiothoracic ratio in 135 at-risk pregnancies. Forty-three fetuses were affected by homozygous type 1 alpha-thalassemia. The mean cardiothoracic ratio was significantly larger than that of the unaffected fetuses (0.54 vs 0.45, P <.0005), with no overlap between the 2 groups. A cardiothoracic ratio cutoff point of >/=0.5 was 100% sensitive and specific for disease.
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Lam YH, Tang MH, Lee CP, Tse HY. Cardiac blood flow studies in fetuses with homozygous alpha-thalassemia-1 at 12-13 weeks of gestation. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 1999; 13:48-51. [PMID: 10201086 DOI: 10.1046/j.1469-0705.1999.13010048.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE Fetuses affected by homozygous alpha-thalassemia-1 develop anemia as early as the first trimester. Our objective was to study hemodynamic indices in affected fetuses at 12-13 weeks of gestation to determine whether these would be useful in the prediction of anemia. DESIGN Prospective observational study. SUBJECTS Women referred before 14 weeks of gestation for the prenatal diagnosis of homozygous alpha-thalassemia-1. METHODS Transabdominal and/or transvaginal Doppler sonography was performed to measure the flow velocities in the fetal ascending aorta and pulmonary artery at 12-13 weeks. The Doppler indices were compared between those that were subsequently confirmed to be affected by homozygous alpha-thalassemia-1 and those that were unaffected. RESULTS Between June 1997 and April 1998, 60 eligible women were recruited. Doppler examination was successful in 58 fetuses. Of these, 22 were subsequently confirmed to be affected by homozygous alpha-thalassemia-1. The diagnosis was made by chorionic villus sampling and DNA analysis in two affected fetuses and by cordocentesis and hemoglobin evaluation in 20 affected fetuses. Hemoglobin concentrations could be measured in ten fetuses and these ranged from 4 to 8 g/dl. The affected fetuses had significantly higher peak velocities at the pulmonary valve and ascending aorta and a larger inner diameter of the pulmonary valve than that in unaffected fetuses. The total cardiac output was increased by one-third in affected fetuses and was mainly due to an increase of the right-side cardiac output. CONCLUSION In the early stage of anemia, the fetus responds mainly by increasing its right-side cardiac output. However, there is extensive overlap of the values of cardiac output between the affected and the unaffected fetuses, precluding its use in the prediction of anemia.
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Lee CP, Elhassan YM, Kraemer DC. The effect of β-mercaptoethanol and n-acetyl cysteine on development and hatching of bovine blastocysts produced in vitro. Theriogenology 1999. [DOI: 10.1016/s0093-691x(99)91802-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lam YH, Lee CP, Tang MH. Low second-trimester maternal serum human chorionic gonadotrophin in a trisomy 9 pregnancy. Prenat Diagn 1998; 18:1212. [PMID: 9854737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Li J, Tamura K, Lee CP, Smith PL, Borchardt RT, Hidalgo IJ. Structure-affinity relationships of Val-Val and Val-Val-Val stereoisomers with the apical oligopeptide transporter in human intestinal Caco-2 cells. J Drug Target 1998; 5:317-27. [PMID: 9771614 DOI: 10.3109/10611869808997860] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The objective of this study was to elucidate the structural features of the stereoisomers of Val-Val and Val-Val-Val that afford optimal binding affinity for the apical oligopeptide transporter in human intestinal Caco-2 cells. Three-dimensional conformations of cephalexin and Val stereoisomers were optimized using Chem-X molecular modeling software. Molecular features associated with the optimized conformations of the Val stereoisomers were analyzed to identify potential relationships with their binding affinities for the apical oligopeptide transporter. For Val-Val stereoisomers, the distance between the N-terminal amino group and the C-terminal carboxyl group, d(N1-C7), was found to have a linear relationship with their binding affinities at the 95% confidence level. For Val-Val-Val stereoisomers, three molecular features were found to have linear relationships with their binding affinities at the 95% confidence level. These features included: a) the distance between the N-terminal amino group and the C-terminal carboxyl group, d(N1-C11); b) the distance between the N-terminal amino group and the second peptide bond, d(N1-N9); and c) the molecular dipole moment. Principal component analysis on all molecular features of Val-Val-Val stereoisomers identified three components that accounted for 90% of the variance. A linear model built with these three components by multiple linear regression adequately described the binding affinities (r2 = 0.90). Results from the current study suggest that the distance between the N-terminal amino group and the C-terminal carboxyl group is important for interaction with the apical oligopeptide transporter in Caco-2 cells. In addition, the binding affinities of the Val-Val-Val stereoisomers appear to be influenced by additional factors, including the position of the second peptide bond and the molecular dipole moment.
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de Vrueh RL, Smith PL, Lee CP. Transport of L-valine-acyclovir via the oligopeptide transporter in the human intestinal cell line, Caco-2. J Pharmacol Exp Ther 1998; 286:1166-70. [PMID: 9732374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
It has been reported that conjugating acyclovir, a potent antiviral with low oral bioavailability, to L-valine increases its urinary excretion in rats. However, it was also reported that this increase is not found for the D-valine ester, suggesting that a carrier-mediated mechanism is involved in its intestinal absorption. Therefore, mechanisms involved in the transepithelial transport of L-valine-acyclovir were investigated using the intestinal cell line, Caco-2, as a model system for the intestinal epithelium. Only the mucosal-to-serosal transport of acyclovir was increased by conjugation with L-valine (approximately 7-fold), suggesting the involvement of a carrier-mediated mechanism. This conclusion was supported by the finding that this increase was saturable. The mucosal-to-serosal transport of L-valine-acyclovir could be inhibited by L-glycylsarcosine, but not by L-valine, suggesting the involvement of the dipeptide carrier. Also it was found that L-valine-acyclovir inhibits the uptake of cephalexin, a substrate for the oligopeptide transporter. Stability of the esters in either the mucosal or serosal bathing solution is more than 90% after completion of the transport study. However, after transport, the receiver solution contained approximately 90% of acyclovir. Based on these findings it was concluded that absorption of the L-valine ester of acyclovir occurs as a result of uptake by the oligopeptide transporter at the apical cell membrane followed by intracellular hydrolysis of the ester and efflux of acyclovir.
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Han H, de Vrueh RL, Rhie JK, Covitz KM, Smith PL, Lee CP, Oh DM, Sadée W, Amidon GL. 5'-Amino acid esters of antiviral nucleosides, acyclovir, and AZT are absorbed by the intestinal PEPT1 peptide transporter. Pharm Res 1998; 15:1154-9. [PMID: 9706043 DOI: 10.1023/a:1011919319810] [Citation(s) in RCA: 242] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE General use of nucleoside analogues in the treatment of viral infections and cancer is often limited by poor oral absorption. Valacyclovir, a water soluble amino acid ester prodrug of acyclovir has been reported to increase the oral bioavailability of acyclovir but its absorption mechanism is unknown. This study characterized the intestinal absorption mechanism of 5' -amino acid ester prodrugs of the antiviral drugs and examined the potential of amino acid esters as an effective strategy for improving oral drug absorption. METHODS Acyclovir (ACV) and Zidovudine (AZT) were selected as the different sugar-modified nucleoside antiviral agents and synthesized to L-valyl esters of ACV and AZT (L-Val-ACV and L-Val-AZT), D-valyl ester of ACV (D-Val-ACV) and glycly ester of ACV (Gly-ACV). The intestinal absorption mechanism of these 5' -amino acid ester prodrugs was characterized in three different experimental systems; in situ rat perfusion model, CHO/hPEPT1 cells and Caco-2 cells. RESULTS Testing 5' -amino acid ester prodrugs of acyclovir and AZT, we found that the prodrugs increased the intestinal permeability of the parent nucleoside analogue 3- to 10-fold. The dose- dependent permeation enhancement was selective for L-amino acid esters. Competitive inhibition studies in rats and in CHO cells transfected with the human peptide transporter, hPEPT1, demonstrated that membrane transport of the prodrugs was mediated predominantly by the PEPT1 H+/dipeptide cotransporter even though these prodrugs did not possess a peptide bond. Finally, transport studies in Caco-2 cells confirmed that the 5' - amino acid ester prodrugs enhanced the transcellular transport of the parent drug. CONCLUSIONS This study demonstrates that L-amino acid-nucleoside chimeras can serve as prodrugs to enhance intestinal absorption via the PEPT1 transporter, providing a novel strategy for improving oral therapy of nucleoside drugs.
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Xiong Y, Peterson PL, Verweij BH, Vinas FC, Muizelaar JP, Lee CP. Mitochondrial dysfunction after experimental traumatic brain injury: combined efficacy of SNX-111 and U-101033E. J Neurotrauma 1998; 15:531-44. [PMID: 9674556 DOI: 10.1089/neu.1998.15.531] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We recently demonstrated that posttraumatic administration of the N-type calcium channel blocker SNX-111 (S) and a novel blood-brain barrier penetrating antioxidant U-101033E (U), significantly alleviated mitochondrial dysfunction induced by traumatic brain injury (TBI) in rats. The present study was designed to determine whether a combination of S and U, which act on different biochemical mechanisms of secondary brain injury, would be more efficacious than either drug alone. Brain mitochondria from injured and uninjured hemispheres were isolated and examined at 12 h post TBI induced by a severe controlled cortical impact injury. S at 1.0 mg/kg significantly increased both State 3 and 4 rates and produced a slight increase in P/O ratio, and there was virtually no change in RCI. U at 1.0 mg/kg did not show any protection. However, the combined treatment of S at 1.0 mg/kg and U at 1.0 mg/kg eliminated the uncoupling effect of S, and restored not only State 3 rates and P/O ratios but also RCI to near sham values. These results provide further evidence that both reactive oxygen species and perturbation of cellular calcium homeostasis participate in the pathogenesis of TBI-induced mitochondrial dysfunction, and support the idea of using combined therapy with lower drug doses.
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Lam YH, Ghosh A, Tang MH, Tang LC, Lee CP, Sin SY, Ho PK. Second-trimester maternal serum alpha-fetoprotein and human chorionic gonadotrophin screening for Down's syndrome in Hong Kong. Prenat Diagn 1998; 18:585-89. [PMID: 9664604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Second-trimester maternal serum screening for fetal Down's syndrome is well established in many Western countries. Its usefulness and acceptability is unknown in the Asian countries. Between June 1994 and December 1996, we offered second-trimester serum AFP and hCG screening to pregnant women in Hong Kong who were less than 35 years old and without other risk factors for chromosome abnormalities. Each woman was assigned a risk of having a Down's syndrome term pregnancy by using a computer software program that took into account her age. weight, AFP and hCG MOMs. All those with a risk of one in 250 or greater were designated screen-positive, subject to the revision of gestation by ultrasound examination. 9,177 women with singleton pregnancies (93 per cent were Chinese) were screened. The uptake of screening was 75 per cent. 281 women (three per cent) were initially classified to be screen-positive. After revision of the gestation by ultrasound examination, 183 women (two per cent) were 'true' screen-positive and 164 (90 per cent) accepted the offer of amniocentesis. Eight of these pregnancies were affected by Down's syndrome and all the women elected pregnancy termination. The odds of being affected, given a positive screening result, were one in 23. Six Down's syndrome pregnancies were missed by screening programme. The detection rate was 57 per cent. The study showed that second-trimester serum screening for fetal Down's syndrome was feasible and accepted in the Hong Kong population.
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