Biomedical subjects
Publications and source records attributed to M Lin.
Five stilbene dimers, gnetuhainins F-J, were isolated together with gnetulin, rhapontigenin, isorhapontigenin and gnetol from the lianas of Gnetum hainanense C. Y. Cheng. Their structures and stereochemistry have been established on the basis of spectral evidence, especially 2D NMR spectroscopic techniques.
Seizure disorder and sleep apnea are common chronic disorders in children, but the relationship between sleep apnea and seizure control has not been studied in the pediatric population. This retrospective review included nine children with neurodevelopmental disorders who had well-documented sleep apneic episodes and seizure disorders. Seizure frequency was reduced in five patients (56%) in the first 12 months after sleep apnea treatment without changes in their antiepileptic medications. Sleep apnea can be one of the seizure precipitants in children with epilepsy. This study indicates the importance of identifying sleep apnea when treating children with intractable epilepsy, particularly in those who are at high risk.
Five new stilbene dimers, gnetuhainins A-E (1-5), were isolated together with resveratrol trans-dehydrodimer (6), resveratrol, oxyresveratrol, and (-)-epsilon-viniferin from the lianas of Gnetum hainanense. Their structures and stereochemistry were determined on the basis of their chemical and spectral data. Compounds 1-5 are dimers formed by a resveratrol unit and an oxyresveratrol unit and belong to a new type of oligostilbenes polymerized from two different stilbene units.
Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.
Spermatogenesis in the platypus (Ornithorhynchus anatinus) is of considerable biological interest as the structure of its gametes more closely resemble that of reptiles and birds than marsupial or eutherian mammals. The ultrastructure of 16 steps of spermatid development is described and provides a basis for determining the kinetics of spermatogenesis. Steps 1-3 correspond to the Golgi phase of spermatid development, steps 4-8 correspond to the cap phase, steps 9-12 are the acrosomal phase, and steps 13-16 are the maturation phase. Acrosomal development follows the reptilian model and no acrosomal granule is formed. Most other features of spermiogenesis are similar to processes in reptiles and birds. However, some are unique to mammals. For example, a thin, lateral margin of the acrosome of platypus sperm expands over the nucleus as in other mammals, and more than in reptiles and birds. Also, a tubulobulbar complex develops around the spermatid head, a feature which appears to be unique to mammals. Further, during spermiation the residual body is released from the caudal end of the nucleus of platypus sperm leaving a cytoplasmic droplet located at the proximal end of the middle piece as in marsupial and eutherian mammals. Other features of spermiogenesis in platypus appear to be unique to monotremes. For example, nuclear condensation involves the formation of a layer of chromatin granules under the nucleolemma, and development of the fibrous sheath of the principal piece starts much later in the platypus than in birds or eutherian mammals.
This study was designed to investigate the effects of preinfusion with total parenteral nutrition (TPN) using medium-chain triglycerides (MCT) versus safflower oil (SO) emulsion as fat sources on hepatic lipids, plasma amino acid profiles, and inflammatory-related mediators in septic rats. Normal rats, with internal jugular catheters, were divided into two groups and received TPN. TPN provided 300kcal/kg/day with 40% of the non-protein energy provided as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was made of SO or a mixture of MCT and soybean oil (9:1) (MO). After receiving TPN for 6 days, each group of rats was further divided into control and sepsis subgroups. Sepsis was induced by cecal ligation and puncture, whereas control rats received sham operation. All rats were classified into four groups as follows: MCT control group (MOC, n= 8), MCT sepsis group (MOS, n= 8), safflower oil control group (SOC, n= 8), and safflower oil sepsis group (SOS, n= 11). The results of the study demonstrated that the MOS group had lower hepatic lipids than did the SOS group. Plasma leucine and isoleucine levels were significantly lower in the SOS than in the SOC group, but no differences in these two amino acids were observed between the MOC and MOS groups. Plasma arginine levels were significantly lower in septic groups than in those without sepsis despite whether MCT or safflower oil was infused. Plasma glutamine and alanine levels, however, did not differ between septic and non-septic groups either in the SO or MO groups. No differences in interleukin-1b, interleukin-6, tumor necrosis factor-alpha, and leukotriene B(4)concentrations in peritoneal lavage fluid were observed between the two septic groups. These results suggest that catabolic reaction is septic rats preinfused MCT is not as obvious as those preinfused safflower oil. Compared with safflower oil, TPN with MCT administration has better effects on reducing sepsis-induced liver fat deposition. Preinfusion with MCT before sepsis, however, had no effect on inflammatory-related cytokines or leukotriene in peritoneal lavage fluid. In addition, plasma arginine appears to be a more sensitive indicator than glutamine for septic insult.
A new dimeric stilbene, named shegansu B (1) was isolated from the ethanolic extract of the roots of Belamtantida chinensis (L.) DC., along with the known compounds isorhapontigenin, resveratol, p-hydroxybenzoic acid, iridin, tectoridin, tectorigenin and daucosterol. The structures were elucidated by means of spectroscopic evidence including 2D-NMR studies.
OBJECTIVES: To collect smoking-related data from Chinese patients attending Chinese-speaking general practitioners (CSGPs), including self-reported smoking status, recall of a question about smoking status during the previous six months by their GP and, for smokers, their recall of quit advice in their most recent consultation. DESIGN: Descriptive research first involving self-administered waiting-room questionnaires and, afterwards, a second self-administered questionnaire to examine behaviour in that most recent consultation. SETTING: Surgeries of 24 CSGPs in Central Sydney. SUBJECTS: 1084 Chinese patients aged 18-70 years. RESULTS: Self-reported smoking prevalence was 25% (95% CI: 21%-29%) for men and 4% (95% CI: 2%-5%) for women. Of 103 smokers who had visited their regular GP during the previous 6 months, 42% recalled a question about smoking status and 38% quit advice. As elicited at follow-up, 72% recalled any discussion in their most recent consultation about smoking although effective techniques were rarely recalled. Patient's sex (OR: 1.78; 95% CI: 1.28-2.47) and smoking status (OR: 1.39; 2.38; 95% CI: 0.85-2.25, 1.49-3.81) independently predicted a question about smoking status. Among smokers, marital status was the only independent predictor of quit advice. As assessed by a stage-of-change scale, significantly more Chinese smokers were not ready to contemplate cessation, compared with Angio-Celtic community survey results. CONCLUSIONS: Our study provides unique information about smoking among ethnic Chinese patients attending CSGPs. Findings also suggest CSGPs need greater support to maximize their clinical opportunities to advise Chinese smokers to quit.
OBJECTIVE: To determine patient characteristics associated with patient and proxy perceptions of physicians' recommendations for life-prolonging care versus comfort care, and with acceptance of such recommendations. DESIGN: Cross-sectional. SETTING: Five teaching hospitals in Denver, Colo. PATIENTS: We studied 239 hospitalized adults believed by physicians to have a high likelihood of dying within 6 months. MEASUREMENTS AND MAIN RESULTS: Interviews with patients or proxies were conducted to determine perceptions of physicians' recommended goal of care and roles in decision making. RESULTS: Patients' mean age was 66.6 years; 44% were women. In adjusted analysis, age greater than 70 years and female gender were associated with a higher likelihood of believing that comfort care had been recommended by the physician (odds ratio [OR], 3.70; 95% confidence interval [CI], 1.89 to 7.24; OR, 1.99; 95% CI, 1.04 to 3. 84, respectively). Patients and proxies gave substantial decision-making authority to physicians: 29% responded that physicians dominate decision making, 55% that decision making is equally shared by physicians and patients, and only 16% that patients make decisions. Increasing age was associated with an increased likelihood of believing that physicians should dominate decision making (P <.005). CONCLUSIONS: Among patients with advanced illness, perceived comfort care recommendations were related to patient age and gender, raising concern about possible gender and age bias in physicians' recommendations. Although all patients and proxies gave significant decision-making authority to physicians, older individuals were more likely to give physicians decision-making authority, making them more vulnerable to possible physician bias.
OBJECTIVES: To compare treatment and outcomes for older persons with stroke in Medicare health maintenance organizations (HMOs) and fee-for-service (FFS) systems. DESIGN: Inception cohort stratified by payer and followed for 1 year. SETTING: Six HMOs and five FFS systems with large Medicare populations in the West, Midwest, and Eastern United States. PARTICIPANTS: A total of 429 randomly selected stroke patients receiving rehabilitation in nursing homes or rehabilitation hospitals (RHs) from June 1993 to June 1995. MEASUREMENTS: Improvement in activities of daily living (ADLs) during rehabilitation, and ADL recovery, community residence, and utilization until 12 months after stroke. Outcomes were adjusted for premorbid function, marital status, comorbid illness, posthospital function, cognition, psychological problems, and stroke deficits. RESULTS: At baseline, HMO patients were more likely to be married, and less likely to be blind or have psychiatric diagnoses. HMO patients had shorter hospitalizations (P < .001), were less likely to be admitted to RHs (13% vs 85%, P < .001), and received fewer therapy and physician specialist visits (P < .001) but more home health visits (P < .001). During rehabilitation, FFS patients made greater improvement in ADLs (difference, 0.73 ADLs; 95% CI, .37-1.09). At 1 year, there was no difference in ADL recovery (difference, -0.24 ADL; 95% CI, -0.64-0.16), but FFS patients were more likely to reside in the community (adjusted OR, 1.8; 95% CI, 1.1-3.1), and HMO patients were more likely to reside in nursing homes (adjusted OR, 2.4; 95% CI, 1.1-5.5). CONCLUSION: Study findings suggest that short-term functional outcomes and eventual community residence rates are poorer for Medicare HMO patients with stroke than for stroke patients receiving FFS care, consistent with the lower intensity of rehabilitation (in nursing homes vs RHs) and less specialty physician care.
The major structural glycoprotein E2 of classical swine fever virus (CSFV) is responsible for eliciting neutralizing antibodies and conferring protective immunity. The current structural model of this protein predicts its surface-exposed region at the N terminus with a short stretch of the C-terminal residues spanning the membrane envelope. In this study, the N-terminal region of 221 amino acids (aa) covering aa 690 to 910 of the CSFV strain Alfort/187 E2, expressed as a fusion product in Escherichia coli, was shown to contain the epitope recognized by a monoclonal antibody (WH303) with affinity for various CSFV strains but not for the other members of the Pestivirus genus, bovine viral diarrhea virus (BVDV) and border disease virus (BDV). This region also contains the sites recognized by polyclonal immunoglobulin G (IgG) antibodies of a pig hyperimmune serum. Serial deletions of this region precisely defined the epitope recognized by WH303 to be TAVSPTTLR (aa 829 to 837) of E2. Comparison of the sequences around the WH303-binding site among the E2 proteins of pestiviruses indicated that the sequence TAVSPTTLR is strongly conserved in CSFV strains but highly divergent among BVDV and BDV strains. These results provided a structural basis for the reactivity patterns of WH303 and also useful information for the design of a peptide containing this epitope for potential use in the detection and identification of CSFV. By deletion analysis, an antigenic domain capable of reacting with pig polyclonal IgG was found 17 aa from the WH303 epitope within the N-terminal 123 residues (aa 690 to 812). Small N- or C-terminal deletions introduced into the domain disrupt its reactivity with pig polyclonal IgG, suggesting that this is the minimal antigenic domain required for binding to pig antibodies. This domain could have eliminated or reduced the cross-reactivity with other pestiviruses and may thus have an application for the serological detection of CSFV infection; evaluation of this is now possible, since the domain has been expressed in E. coli in large amounts and purified to homogeneity by chromatographic methods.
The purpose of this study was to determine whether early alcohol-induced liver injury (ALI) in females is associated with changes in CD14 on Kupffer cells, activation of hepatic nuclear factor (NF)-kappaB, and expression of tumor necrosis factor (TNF)-alpha mRNA. Male and female rats were given high-fat control or ethanol-containing diets for 4 wk using the intragastric enteral protocol. Physiological parameters were similar in both genders. Ethanol was increased as tolerance developed with higher blood levels than previously observed, resulting in a fourfold increase in aspartate aminotransferase (males 389 +/- 47 IU/l vs. females 727 +/- 66 IU/l). Hepatic pathology developed more rapidly and was nearly twofold greater and endotoxin levels were significantly higher in females after ethanol. Also, expression of CD14 on Kupffer cells was 1.5-fold greater and binding of transcription factor NF-kappaB in hepatic nuclear extracts and TNF-alpha mRNA expression were threefold greater in females. These data are consistent with the hypothesis that elevated endotoxin after ethanol triggers more activation of Kupffer cells via enhanced CD14 expression in females. NF-kappaB is activated in this process, leading to increases in TNF-alpha mRNA expression in the liver and more severe liver injury in females. It is concluded that gender differences in ALI are dependent on endotoxin and a signaling cascade leading to TNF-alpha.
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Only a fraction of the clinical complications of atherosclerosis are explained by known risk factors. Animal studies have shown that plasma sphingomyelin (SM) levels are closely related to the development of atherosclerosis. SM carried into the arterial wall on atherogenic lipoproteins may be locally hydrolyzed by sphingomyelinase, promoting lipoprotein aggregation and macrophage foam cell formation. A novel, high-throughput, enzymatic method to measure plasma SM levels has been developed. Plasma SM levels were related to the presence of coronary artery disease (CAD) in a biethnic angiographic case-control study (279 cases and 277 controls). Plasma SM levels were higher in CAD patients than in control subjects (60+/-29 versus 49+/-21 mg/dL, respectively; P:<0. 0001). Moreover, the ratio of SM to SM+phosphatidylcholine (PC) was also significantly higher in cases than in controls (0.33+/-0.13 versus 0.29+/-0.10, respectively; P:<0.0001). Similar relationships were observed in African Americans and whites. Plasma SM levels showed a significant correlation with remnant cholesterol levels (r=0.51, P:<0.0001). By use of multivariate logistic regression analysis, plasma SM levels and the SM/(SM+PC) ratio were found to have independent predictive value for CAD after adjusting for other risk factors, including remnants. The odds ratio (OR) for CAD was significantly higher for the third and fourth quartiles of plasma SM levels (OR 2.81 [95% CI 1.66 to 4.80] and OR 2.33 [95% CI 1.38 to 3. 92], respectively) as well as the SM/(SM+PC) ratio (OR 1.95 [95% CI 1.10 to 3.45] and OR 2.33 [95% CI 1.34 to 4.05], respectively). The findings indicate that human plasma SM levels are positively and independently related to CAD. Plasma SM levels could be a marker for atherogenic remnant lipoprotein accumulation and may predict lipoprotein susceptibility to arterial wall sphingomyelinase.
A medium modified from eutherian systems was used to culture epididymal epithelial cells of the brushtail possum (Trichosurus vulpecula) for more than 2 months. Epididymal tubule fragments from the caput, corpus and cauda epididymides were used to generate cell monolayers. All three epididymal cell culture systems supported maturational changes in marsupial spermatozoa and enabled immature possum spermatozoa to differentiate from a T-shape to a streamlined shape, accompanied by the development of progressive motility after co-culture with 7-day-old cultured epididymal cell monolayers. This epididymal cell and sperm co-culture system for marsupial species may facilitate the identification of specific epithelial factors that affect sperm maturation, particularly in a species in which morphological maturation is readily visible.
An effective national surveillance system is an essential component of a program for the control of influenza. The National Influenza Surveillance Scheme includes data from sentinel general practice consultations for influenza-like illness, laboratory reports of influenza and absenteeism rates from a national employer. The 1999 season peaked between May and September with maximal activity between July and August. Influenza A was the dominant type in all States and Territories with influenza A H3N2 viruses predominating and influenza A H1N1 occurring sporadically. There was no evidence of significant drift among the H3N2 isolates (A/Sydney-like strains) whereas the H1N1 isolates showed significant antigenic changes from the vaccine strain A/Beijing/262/95 and were closely related to a new variant A/New Caledonia/20/99. A small peak in influenza B activity occurred towards the end of the influenza season and isolates remained closely related to the vaccine reference strain B/Beijing/184/93.
Phospholipid transfer protein gene knock-out (Pltp KO) mice have defective transfer of very low density lipoprotein (VLDL) phospholipids into high density lipoprotein (HDL) and markedly decreased HDL levels (Jiang et al. 1999. J. Clin. Invest. 103: 907-914). These animals also accumulated VLDL- and LDL-sized lipoproteins on a high saturated fat diet. The goals of this study were to further characterize the abnormal lipoproteins of Pltp KO mice and to determine the mechanisms responsible for low HDL levels. A lipoprotein fraction enriched in lamellar structures was isolated from the low density lipoprotein (LDL) region and was shown to be phospholipid- and free cholesterol-rich and to have apoA-IV (55%) and apoE (25%) as major apolipoproteins. The lamellar lipoproteins accumulating in these mice probably represent surface material derived from triglyceride-rich lipoproteins (TRL). The HDL was found to be protein-rich (primarily apoA-I) and specifically depleted in phosphatidylcholine (PC) (28% in wild-type mice (WT) vs. 15% in Pltp KO mice, P < 0.001). Unexpectedly, turnover studies using autologous HDL revealed a profound 4-fold increase in the catabolism of HDL protein and cholesteryl ester in Pltp KO mice compared to wild-type, with minor differences in synthesis rates. In contrast, injection of WT mouse HDL into Pltp KO mice showed only a 2-fold increase in fractional catabolism. Reminiscent of the defect in Tangier disease, the failure of transfer of PC from TRL into the HDL fraction results in dramatic hypercatabolism of HDL. These results suggest that defective phospholipid transfer from TRL into HDL, arising from decreased lipolysis or decreased PLTP activity, could lead to hypoalphalipoproteinemia characterized by hypercatabolism of HDL protein. lipoprotein levels, due to hypercatabolism, and accumulate apoA-IV-rich lamellar lipoproteins.
OBJECTIVE: To investigate the effect of neutrophil activation on pathogenesis of preeclampsia. METHODS: In 22 pregnant women with preeclampsia and 21 normal pregnant women at third trimester, neutrophil activation was examined by flow cytometry to assess the CD11b expression, and the levels of plasma endothelin-1 (ET-1) and serum NO2- were also measured with no-equilibrium radio-immunoassay and with Griess assay respectively. RESULTS: The expression of neutrophil CD11b was significantly elevated in women with preeclampsia compared with that of normal pregnant women at third trimester [the mean fluorescence index of CD11b were 439.1 +/- 169.1 and 321.2 +/- 166.3 respectively, P < 0.05], the plasma ET-1 level and serum NO2- concentration in preeclampsic women [(61.4 +/- 48.2) ng/L and (20.4 +/- 5.2) mumol/L, respectively] were both significantly increased compared with those in the normal pregnancy women [(29.3 +/- 20.9) ng/L and (15.5 +/- 4.8) mumol/L, respectively], (P < 0.01). The mean fluorescence index of CD11b was significantly correlated with plasma ET-1 level and serum NO2- concentration (r = 0.312 and 0.382, respectively, P < 0.05). But the correlation between the plasma ET-1 level and serum NO2- concentration was not found (r = 0.227, P > 0.05). CONCLUSIONS: The neutrophil CD11b expression is significantly elevated in preeclampsia. The increased neutrophil activation may cause the damage of vascular endothelium and result in compensatory increase of NO release in endothelial cells. It suggests that the neutrophil activation may play a key role in pathogenesis of preeclampsia.