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Biomedical subjects

S Lai

Publications and source records attributed to S Lai.

At least 55 records · Page 3Linked to original sources
PubMed2000

Numerical phenetic study of the genus Carnobacterium.

Eighty-nine strains representing the genus Carnobacterium, Enterococcus durans, Vagacoccus salmoninarum and atypical Lactobacillus strains MT12 and MT13 were examined for 92 unit characters. Computer analysis of the data resulted in the recovery of four major, five minor and thirteen single membered clusters. Three cluster-groups contained seventy-four of the Carnobacterium strains, Enterococcus durans NCFB 596T and Lactobacillus maltaromicus NCFB 2382T. Cluster-group A was equated with Carnobacterium piscicola and cluster-group B with Carnobacterium divergens. Lactobacillus maltaromicus NCFB 2382T shared many properties in common with the C. piscicola strains. The recovery of several Carnobacterium strains as single membered clusters suggests that the genus Carnobacterium is underspeciated. Further work is also required to determine the subspecific structure of Carnobacterium divergens and Carnobacterium piscicola.

Bacterial Typing Techniques↗
PubMed2000

Three-dimensional ultrasound in the evaluation of fetal anomalies.

OBJECTIVES: To determine the additional information and clinical impact provided by three-dimensional ultrasound (3D US) imaging of fetal anomalies compared to conventional 2-dimensional ultrasound (2D US). MATERIALS AND METHODS: Sixty-three patients with 103 anomalies were scanned prospectively with both 2D and 3D US. Each anomaly was reviewed by one or more fetal imaging specialists to determine whether the 3D US data were advantageous, equivalent, or disadvantageous when compared with 2D US images. Clinical impact and pathologic or clinical outcome were determined in all cases. RESULTS: The 3D US images provided additional information in 53 anomalies (51%), were equivalent to 2D US images in 46 anomalies (45%), and were disadvantageous in four anomalies (4%). The 3D US was most helpful in evaluating fetuses with facial anomalies, hand and foot abnormalities and axial spine and neural tube defects. Planar images derived from 3D US volume data sets generally were more helpful for diagnostic purposes, whereas rendered 3D US images were more useful as a point of reference and were better appreciated by patients in understanding fetal abnormalities. Additional information provided by 3D US images impacted clinical management in 5% of patients. The 3D US images were disadvantageous in two fetuses with multiple anomalies and two with cardiac anomalies. CONCLUSION: The 3D US offered diagnostic advantages in about one-half of the selected cases studied and had effect on patient management in 5% of cases. This modality can be a powerful adjunctive tool to 2D US in providing a more comprehensible, 3D US impression of congenital anomalies. Thus, 3D US is currently most helpful as a targeted study complementing 2D US.

Congenital Abnormalities↗
PubMed2000

The differentiation of Carnobacterium divergens using the random amplification of polymorphic DNA polymerase chain reaction technique.

The potential of the randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) technique to differentiate Carnobacterium divergens from other members of the genus Carnobacterium was examined. A numerical analysis of the genomic profiles obtained demonstrated that it was possible to differentiate the C. divergens strains from other Carnobacterium strains using this technique. The heterogeneity observed in the representatives of the species C. piscicola adds further weight to the suggestion in other taxonomic studies that subspecies of this species exist.

Bacteria↗
PubMed2000

Linear and nonlinear analysis of hemodynamic signals during sepsis and septic shock.

OBJECTIVE: Neuroautonomic modulation of heart rate (HR) and blood pressure were assessed in sepsis or septic shock. We hypothesized that these metrics would be diminished in pediatric patients with sepsis and septic shock, indicating uncoupling of the autonomic and cardiovascular systems. DESIGN: Prospective case series. SETTING: Pediatric intensive care unit in a tertiary care children's hospital. PATIENTS: Thirty pediatric patients with sepsis or septic shock. INTERVENTIONS: None. MEASURES AND MAIN RESULTS: Metrics used included power spectral analysis, a linear frequency domain measure, and detrended fluctuation analysis, a nonlinear technique that assesses the degree of long-range correlation in HR or blood pressure. We found decreased low-frequency (2.68 +/- 0.24 vs. 3.37 +/- 0.17 [SEM] bpm2; p = .03) and high-frequency HR power (2.18 +/- 0.14 vs. 2.79 +/- 0.23 bpm2; p = .04) and increased detrended fluctuation analysis scaling exponent (1.22 +/- 0.06 vs. 1.00 +/- 0.07 bpm2; p = .02) in sepsis vs. shock patients, respectively. Compared with sepsis or shock, recovery was associated with increases in low-frequency (3.61 +/- 0.15 vs. 3.05 +/- 0.19 bpm2; p < .0001) and high-frequency HR power (3.11 +/- 0.15 vs. 2.50 +/- 0.22 bpm2; p < .0001). CONCLUSIONS: We conclude that uncoupling of the autonomic and cardiovascular systems occurs over both short- and long-range time scales during sepsis, and the degree of uncoupling may help differentiate between sepsis, septic shock, and recovery states.

Adolescent↗
PubMed2000

A recent outbreak of human immunodeficiency virus type 1 infection in southern China was initiated by two highly homogeneous, geographically separated strains, circulating recombinant form AE and a novel BC recombinant.

New outbreaks of human immunodeficiency virus type 1 (HIV-1) among injecting drug users (IDUs) are spreading in China along heroin trafficking routes. Recently, two separate HIV-1 epidemics among IDUs were reported in Guangxi, Southern China, where partial sequencing of the env gene showed subtype C and circulating recombinant form (CRF) AE. We evaluated five virtually full-length HIV-1 genome sequences from IDUs in Guangxi to determine the genetic diversity and the presence of intersubtype recombinants. Sequence analysis showed two geographically separated, highly homogeneous HIV-1 strains. B/C intersubtype recombinants were found in three IDUs from Baise City, in a mountainous region near the Yunnan-Guangxi border. These were mostly subtype C, with portions of the capsid and reverse transcriptase (RT) genes from subtype B. The subtype B portion of the capsid was located in the N-terminal domain, which has been shown to influence virus core maturation, virus infectivity, and binding to cyclophilin A, whereas the subtype B portion of RT was located in the palm subdomain, which is the active site of the enzyme. These BC recombinants differed from a BC recombinant found in Xinjiang Province in northwestern China. CRF AE strains were found in IDUs from Nanning, the capital of Guangxi, and in IDUs from Pingxiang City near the China-Vietnam border. The AE and BC recombinants were both remarkable for their low interpatient diversity, less than 1% for the full genome. Rapid spread of HIV-1 among IDUs may foster the emergence of highly homogeneous strains, including novel recombinants in regions with multiple subtypes.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Responses to rare visual target and distractor stimuli using event-related fMRI.

Previous studies have found that the P300 or P3 event-related potential (ERP) component is useful in the diagnosis and treatment of many disorders that influence CNS function. However, the anatomic locations of brain regions involved in this response are not precisely known. In the present event-related functional magnetic resonance imaging (fMRI) study, methods of stimulus presentation, data acquisition, and data analysis were optimized for the detection of brain activity in response to stimuli presented in the three-stimulus oddball task. This paradigm involves the interleaved, pseudorandom presentation of single block-letter target and distractor stimuli that previously were found to generate the P3b and P3a ERP subcomponents, respectively, and frequent standard stimuli. Target stimuli evoked fMRI signal increases in multiple brain regions including the thalamus, the bilateral cerebellum, and the occipital-temporal cortex as well as bilateral superior, medial, inferior frontal, inferior parietal, superior temporal, precentral, postcentral, cingulate, insular, left middle temporal, and right middle frontal gyri. Distractor stimuli evoked an fMRI signal change bilaterally in inferior anterior cingulate, medial frontal, inferior frontal, and right superior frontal gyri, with additional activity in bilateral inferior parietal lobules, lateral cerebellar hemispheres and vermis, and left fusiform, middle occipital, and superior temporal gyri. Significant variation in the amplitude and polarity of distractor-evoked activity was observed across stimulus repetitions. No overlap was observed between target- and distractor-evoked activity. These event-related fMRI results shed light on the anatomy of responses to target and distractor stimuli that have proven useful in many ERP studies of healthy and clinically impaired populations.

Adult↗
PubMed2000

The association between cigarette smoking and drug abuse in the United States.

Cigarette smoking has been identified as an independent risk factor for many human diseases. However, the association between cigarette smoking and illegal drug use has not been thoroughly investigated. We have analyzed the 1994 National Household Survey on Drug Abuse to clarify whether cigarette smoking has any effect on the initiation of illegal drug use. Data from 17,809 respondents completing the 1994 "new" (1994-B) questionnaire were analyzed. Logistic regression analyses were performed with the use of statistical package SUDAAN, taking into consideration the multistage sampling design. The results show that those who had smoked cigarettes were far more likely to use cocaine (OR = 7.5; 95% CI: 5.7-9.9), heroin (OR = 16.0; 95% CI: 6.8-37.9), crack (OR = 13.9; 95% CI: 7.9-24.5) and marijuana (OR = 7.3; 95% CI: 6.2-8.7). The associations are consistent across age-strata and remain after adjusting for race and gender. This study suggests that cigarette smoking may be a gateway drug to illegal drug use.

Adolescent↗
PubMed2000

Glandular odontogenic cyst: a case report.

Glandular odontogenic cyst (GOC) is an extremely rare lesion occurring in the jawbones. Sialo-odontogenic cyst was first described as a multicystic lesion resembling a botryoid odontogenic cyst (BOC) or a central mucoepidermoid carcinoma by Padayachee in 1987. In 1988, Gardner used the term "glandular odontogenic cyst" and considered it as a histologic variant of BOC. Most authors agreed that GOC was odontogenic because of the concurrent ball-like epithelial structure, ameloblastoma, squamous odontogenic tumor-like proliferation in its wall, or hyaline bodies in the epithelium lining. Recently, immunohistochemical studies of the cytokeratin profiles have also supported this concept. Its aggressive behavior and the recurrent tendency make it important. A new case of GOC in a 59-year-old male presented as a multilocular radiolucency in the anterior region of the mandible, invading the marrow space by epithelial islands is described with other clinicopathologic features and the literature is briefly discussed.

Humans↗
PubMed2000

Color-Doppler sonography in ophthalmology.

BACKGROUND: With the present study we considered ocular blood flow by the use of color Doppler ultrasound. We compared the most clinically important arteries of both eyes. We valued the central retinal artery, the posterior long ciliary arteries, the posterior brief ciliary arteries and the central retinal vein. METHODS: We submitted to an ecd examination of the ophthalmic arteries 50 patients, of whom 30 were healthy, 4 presented a pallor of the optic disk, 6 were affected by chronic simple glaucoma and 10 were affected by arterial hypertension. RESULTS: This study has allowed us to define the normal and pathologic anatomic findings at the ecd tracing therefore qualitative and quantitative standards of this examination, repeatable and comparable. CONCLUSIONS: Currently the different techniques used to study ocular blood flow, do not allow its exact detection, but only a morphological evaluation of the eye artero-venous system. Acquisition of morphological and velocimetric data, at the same time, allows a more exact evaluation of the pathology. Therefore the ecd is a simple rapid and non-invasive approach, useful in the acquisition of important data concerning diagnostic confirmation, prognosis, and above all pharmacological follow-up of many pathologies such as diabetes, glaucoma and arterial hypertension. The diagnosed vascular alterations are correlated to the degree retinopathy and to the effectiveness of the pharmacological treatment.

Adult↗
PubMed2000

Loss of imprinting and genetic alterations of the cyclin-dependent kinase inhibitor p57KIP2 gene in head and neck squamous cell carcinoma.

The p57KIP2 is a maternally expressed and paternally imprinted cyclin-dependent kinase inhibitor located on chromosome 11p15.5. Because of its location, biochemical functions, and imprinting status, p57KIP2 has been considered a candidate tumor suppressor gene. To determine, for the first time, the involvement of this gene in the development of head and neck squamous carcinoma (HNSC), we analyzed the imprinting and expression status and loss of heterozygosity (LOH) within the p57KIP2 gene flanking loci on the 11p15.5 region in 64 primary untreated tumors. Of the 30 (47%) informative cases for this gene, loss of imprinting and LOH were noted in 4 (13%) and 10 tumors (33%), respectively. Analysis of the microsatellite markers flanking the p57KIP2 gene on chromosome 11p showed infrequent alterations at these loci. p57KIP2 was expressed in all tumors with LOH within and around the gene. Quantitative reverse transcription-PCR analysis showed elevated p57 mRNA expression in tumor with loss of imprinting. Sequencing analysis of exons 1 and 2 of the p57KIP gene failed to detect any mutations. Our data indicate: (a) infrequent genomic abnormalities at the p57KIP2 gene in HNSC; (b) leaky or incomplete imprinting of the paternal allele is associated with increased expression of this gene in a subset of tumors; and (c) minimal evidence for suppressor function for this gene in HNSC.

Carcinoma, Squamous Cell↗
PubMed2000

Fibromyalgia, hypermobility, and breast implants.

OBJECTIVE: To examine possible relationships among fibromyalgia (FM, American College of Rheumatology 1990 criteria), hypermobility, and breast implants. METHODS: The medical records of 2,500 female patients (ages 25-65) who had been seen for the first time in a rheumatology practice in Atlanta, GA, during 1986-92 were abstracted and analyzed. In each analysis, patients whose records indicated that the patient met the full case criteria were compared with patients whose records had no indication of the disease. Patients whose medical records indicated the clinical onset of FM prior to breast implantation were identified. RESULTS: Univariate and multivariate regression analyses were performed, adjusting for age, income, and the presence of connective tissue disease or rheumatoid arthritis. Significant associations were found between hypermobility and FM (adjusted OR 2.20, 95% CI 1.73, 2.80) and between hypermobility and breast implantation (adjusted OR 1.80, 95% CI 1.19, 2.69). No association was found between breast implantation and subsequent FM (adjusted OR 0.74, 95% CI 0.42, 1.32). CONCLUSION: Hypermobility was found to be independently associated with both FM and with breast implantation, but FM and breast implantation were not found to be independently associated with each other.

Adult↗
PubMed2000

[Ethological examination of Alzheimer's disease model rats treated with bushen yizhi decoction].

OBJECTIVE: To explore the ethological improving effect of Bushen Yizhi Decoction (BSYZD) in treating model rat of Alzheimer's disease (AD). METHODS: Ethologic examination was carried out with Morris water maze on young, aged, AD model, Huperzine A treated and BSYZD treated groups of rats. RESULTS: In the BSYZD treated group, the escape latency (EL) curve placed between that of the young, aged and AD model, Huperzine A treated group; the percentage of middle circle swim path, the 40 cm circle swimming time, and the platform-crossing times were not different from those in the normal aged group, but were different significantly as compared with the AD model group, P < 0.05. CONCLUSION: BSYZD could ameliorate the behavior deficits of AD model.

Alzheimer Disease↗
PubMed1999

Frequent loss of imprinting at the IGF2 and H19 genes in head and neck squamous carcinoma.

Genomic imprinting is an inherited epigenetic phenomenon that results in parental-origin-specific gene expression in somatic cells. Relaxation or loss of this feature in certain genes has been demonstrated in several pediatric and adult neoplasms, suggesting an association with tumorigenesis. We analysed 64 primary untreated head and neck squamous carcinoma for the loss of imprinting in the IGF2 and H19 genes to determine the implications of this alteration in the development and progression of these tumors. Forty-nine (77%) of the 64 tumors were informative for imprinting analyses of these genes. IGF2 and H19 were imprinted in all normal squamous epithelium examined. Twelve (37.5%) of 32 tumors informative for H19 and 11 (40.7%) of 27 tumors informative for IGF2 manifested loss of imprinting. Ten tumors were informative for both genes, of which four maintained the constitutional imprinting and six showed loss of imprinting at either H19 or IGF2. These data suggest that loss of imprinting at the IGF2 and H19 loci play a role in the oncogenesis of head and neck carcinoma.

Adult↗
PubMed1999

Emerging HIV infections with distinct subtypes of HIV-1 infection among injection drug users from geographically separate locations in Guangxi Province, China.

Heroin users from Guangxi province, a southern province of China that borders Vietnam in the south and Yunnan province in China in the west, were studied for prevalence and risk factors for HIV-1 infection. Viral env sequences from HIV-1-positive individuals were also determined for subtypes of HIV-1. The overall HIV prevalence among 227 heroin users was 40%. Most had used drugs for < or = 3 years. Sharing of injection equipment and unprotected sex were significantly associated with HIV-1 infection. Subtypes C and E HIV-1 were detected in infected heroin users and were sharply segregated in two geographic locations: only subtype C was found in a border city with Yunnan province, whereas only subtype E was found in a city bordering northern Vietnam. HIV-1 strains within each subtype were remarkably homogenous, with a mean intersubject DNA distance of 2.32% for subtype E and 1.13% for subtype C, respectively. Phylogenetic analysis of C2-V5 region of Guangxi subtype E env sequences revealed significant clustering with subtype E sequences from southern Vietnam and Cambodia. These results suggest that HIV-1 infection among heroin users in Guangxi represents two emerging epidemics initiated from distinct sources: one from Vietnam and another from Yunnan province. Factors associated with HIV-1 infection were not restricted to injection practices. Unprotected sexual behaviors are likely to increase the probability of HIV transmission beyond this high-risk population. Designing and implementing effective intervention strategies targeted toward both injection drug use and high risk sexual behavior are urgently needed to further reduce HIV-1 spread in China.

China↗
PubMed1999

Incremental prognostic value of post-stress left ventricular ejection fraction and volume by gated myocardial perfusion single photon emission computed tomography.

BACKGROUND: The incremental prognostic value of post-stress left ventricular ejection fraction (EF) and volume over perfusion has not been investigated. METHODS AND RESULTS: We identified 1680 consecutive patients who underwent rest Tl-201/stress Tc-99m sestamibi gated single photon emission computed tomography (SPECT) and who were followed-up for 569+/-106 days. Receiver-operator characteristics analysis defined an EF<45%, an end-systolic volume (ESV) >70 mL, and an end-diastolic volume >120 mL as optimal thresholds, yielding moderate sensitivity and high specificity in the prediction of cardiac death. Patients with an EF> or = 45% had mortality rates <1%/year, despite severe perfusion abnormalities, whereas patients with an EF<45% had high mortality rates, even with only mild/moderate perfusion abnormalities (9.2%/year; P<0.00001). Similarly, an ESV< or = 70 mL was related to a low cardiac death rate (<1.2%/year), even for patients with severe perfusion abnormalities, whereas patients with an ESV>70 mL and only mild/moderate perfusion abnormalities had high death rates (8.2%/year; P<0.00001). Patients with an EF<45% and an ESV< or = 70 mL had low cardiac death rates (1.7%/year); those with an EF<45% but an ESV>70 mL had high death rates (7.9%/year; P<0.02). Multivariate Cox proportional hazards regression showed that perfusion variables and ESV were independent predictors of overall coronary events, whereas EF and ESV demonstrated incremental prognostic values over prescan and perfusion information in predicting cardiac death and cardiac death or myocardial infarction. CONCLUSIONS: Post-stress EF and ESV by gated-SPECT have incremental prognostic values over prescan and perfusion information in predicting cardiac death, and they provide clinically useful risk stratification.

Adenosine↗
PubMed1999

Polypeptide resurfacing method improves fibroblast's adhesion to hyaluronan strands.

Hyaluronic acid (hyaluronan, HyA) is a matrix component that takes part in cell adhesion and growth in normal and repaired tissues. Since it is soluble in water, HyA has been of limited use in tissue engineering of artificial matrices. Recent studies demonstrate that polypeptides have the twin advantages of reducing solubility of HyA and improving cellular attachment via cell surface adhesion molecule receptors. This paper describes a new approach of using a polypeptide resurfacing method to enhance the attachment of cells to HyA strands. HyA strands were crosslinked by glutaraldehyde and then resurfaced with poly-D-lysine, poly-L-lysine, glycine, or glutamine. After inoculation with fibroblasts in vitro, modified HyA was evaluated with histological and immunohistochemical staining methods for cell adhesion and proliferation. Modified HyA with fibroblast cells also were implanted in vivo. The results show that (1) both polylysines enhanced fibroblast adhesion to crosslinked HyA strands; (2) HyA strands were able to be crosslinked well by 3 days of treatment in glutaraldehyde, and as a biomaterial they could resist biodegradation; (3) modified HyA has good biocompatibility, both in vitro and in vivo. The results demonstrate that HyA material resurfaced by polypeptides has positive advantages for cellular adhesion. Resurfaced HyA has much potential as an improved biomaterial for clinical usage.

Animals↗
PubMed1999

Keratinocyte growth factor promotes the survival, growth, and differentiation of preantral ovarian follicles.

OBJECTIVE: To determine the effect of treatment with keratinocyte growth factor (KGF) on the survival of cells in cultured preantral follicles and on the growth and differentiation of preantral follicles. DESIGN: Preantral follicles (140-150 microm) were dissected mechanically from the ovaries of 14-day-old rats and cultured for 24 hours with and without KGF. Genomic DNA was extracted, labeled with [32P]-dideoxyadenosine triphosphate, and fractionated through agarose gels. For growth studies, the follicles were cultured individually in 96-well dishes. After 72 hours, the follicles were collected and their protein or DNA content was evaluated and their inhibin-alpha content was determined. RESULT(S): Keratinocyte growth factor suppressed apoptosis in cultured preantral follicles by 60%. Treatment with KGF or FSH increased follicle diameter by 8% and 16%, respectively, and combined treatment with KGF and FSH increased follicle diameter by 26%. Western blot analysis demonstrated increased expression of inhibin-alpha content after treatment with KGF (2-fold), treatment with FSH (4-fold), and combined treatment with FSH and KGF (12-fold), demonstrating the effect of KGF on preantral follicle differentiation. CONCLUSION(S): Treatment with KGF promotes the survival, growth, and differentiation of cultured preantral follicles. Keratinocyte growth factor produced by theca cells may play a role in the progression of early follicle development.

Animals↗