Multiple Correlation Analyses of Metabolic and Endocrine Profiles with Fertility in Primiparous and Multiparous Cows

Results from 4 studies were combined (representing a total of 500 lactations) to investigate the relationships between metabolic parameters and fertility in dairy cows. Information was collected on blood metabolic traits and body condition score at 1 to 2 wk prepartum and at 2, 4, and 7 wk postpartum. Fertility traits were days to commencement of luteal activity, days to first service, days to conception, and failure to conceive. Primiparous and multiparous cows were considered separately. Initial linear regression analyses were used to determine relationships among fertility, metabolic, and endocrine traits at each time point. All metabolic and endocrine traits significantly related to fertility were included in stepwise multiple regression analyses alone (model 1), including peak milk yield and interval to commencement of luteal activity (model 2), and with the further addition of dietary group (model 3). In multiparous cows, extended calving to conception intervals were associated prepartum with greater concentrations of leptin and lesser concentrations of nonesterified fatty acids and urea, and postpartum with reduced insulin-like growth factor-I at 2 wk, greater urea at 7 wk, and greater peak milk yield. In primiparous cows, extended calving to conception intervals were associated with more body condition and more urea prepartum, elevated urea postpartum, and more body condition loss by 7 wk. In conclusion, some metabolic measurements were associated with poorer fertility outcomes. Relationships between fertility and metabolic and endocrine traits varied both according to the lactation number of the cow and with the time relative to calving.

Patterns of lateral pelvic lymph node metastases and micrometastases for patients with lower rectal cancer

AIMS

We aimed at investigating the patterns of lymph node metastases and micrometastases in regions of lateral pelvic area, examining circumferential margin involvement and clarifying their prognostic significance.

METHODS

Large tissue slice and tissue array were adopted in the study of 67 patients with AJCC stages I-III lower rectal cancer who underwent total mesorectal excision with systematic lateral pelvic dissection. The outcomes were followed.

RESULTS

Altogether, 726 lateral lymph nodes were examined, with 32 and 38 were involved by tumor metastases and micrometastases, respectively. Fifty-eight (82.9%) of the involved lymph nodes were smaller than 5mm. Status of lateral nodes was related to that of mesorectal ones. Middle rectal root (45.5%), internal iliac (31.8%) and obturator (22.7%) regions were more likely to be involved by metastases. Patients with lateral metastases, similar to the group with micrometastases, suffered more recurrence and poorer survival when compared with the ones without metastases. The occurrence of circumferential margin involvement suggested poor prognosis and was related to lateral node status.

CONCLUSIONS

In lateral pelvic area, the majority of lymph nodes harboring tumor were small and could easily be neglected by conventional examination. Incidence of lateral metastases differed among regions, thus more attention should be given to the clearance of the highly occurred areas. More extensive range of dissection and/or adjuvant therapy was recommended for patients with lateral node metastases, micrometastases and circumferential margin involvement, since they predisposed poor prognosis.

Treatment of early mixed cellular and humoral renal allograft rejection with tacrolimus and mycophenolate mofetil

This prospective study investigated the efficiency of the tacrolimus (Tac) combined with mycophenolate mofetil (MMF) alone without immunoadsorption (IA) or plasmapheresis (PPH) as treatment for early (within 2 weeks) acute humoral rejection (AHR) in non-sensitized renal allograft recipients. Of 160 patients enrolled in this prospective study, 11 patients had histologically and clinically confirmed early steroid-resistant acute rejection with an antibody response and received Tac-MMF therapy. No other aggressive rescue methods such as IA, PPH were used, according to the study design. Patients (n=11) were followed for 13.8+/-3.5 months; nine were females. The complement-dependent cytotoxicity crossmatch was negative before transplantation in all patients and only positive for panel-reactive antibody in one patient. Most of the rejection episodes were mixed with cellular rejection (four patients met Banff IIA criteria, five patients met Banff IIB, one patient met Banff IB, and one patient met Banff borderline). After 16.19+/-6.16 days of treatment, all rejection episodes were successfully reversed and all graft functions were stable, with a mean serum creatinine level of 1.12+/-0.32 mg/dl during follow-up. No patient suffered from severe infectious complications (except one case of urinary infection). Our investigation suggests that Tac combined with MMF alone is adequate to reverse early mixed cellular and humoral C4d-positive rejection in non-sensitized renal allograft recipients.

Targeting low-arsenic groundwater with mobile-phone technology in Araihazar, Bangladesh

The Bangladesh Arsenic Mitigation and Water Supply Program (BAMWSP) has compiled field-kit measurements of the arsenic content of groundwater for nearly five million wells. By comparing the spatial distribution of arsenic inferred from these field-kit measurements with geo-referenced laboratory data in a portion of Araihazar upazila, it is shown here that the BAMWSP data could be used for targeting safe aquifers for the installation of community wells in many villages of Bangladesh. Recent experiences with mobile-phone technology to access and update the BAMWSP data in the field are also described. It is shown that the technology, without guaranteeing success, could optimize interventions by guiding the choice of the drilling method that is likely to reach a safe aquifer and identifying those villages where exploratory drilling is needed.

Impact of irrigating rice paddies with groundwater containing arsenic in Bangladesh

Soil and soil-water As profiles were obtained from 4 rice paddies in Bangladesh during the wet growing season (May-November), when surface water with little arsenic is used for irrigation, or during the dry season (January-May), when groundwater elevated in arsenic is used instead. In the upper 5 cm of paddy soil, accumulation of 13+/-12 mg/kg acid-leachable As (n=11) was observed in soil from 3 sites irrigated with groundwater containing 80-180 microg/L As, whereas only 3+/-2 mg/kg acid-leachable As (n=8) was measured at a control site. Dissolved As concentrations averaged 370+/-340 microg/L (n=7) in the upper 5 cm of the soil at the 3 sites irrigated with groundwater containing 80-180 microg/L As, contrasting with soil water As concentrations of only 18+/-7 microg/L (n=4) over the same depth interval at the control site. Despite the accumulation of As in soil and in soil water attributable to irrigation with groundwater containing elevated As levels, there is no evidence of a proportional transfer to rice grains collected from the same sites. Digestion and analysis of individual grains of boro winter rice from the 2 sites irrigated with groundwater containing 150 and 180 microg/L As yielded concentrations of 0.28+/-0.13 mg/kg (n=12) and 0.44+/-0.25 mg/kg (n=12), respectively. The As content of winter rice from the control site was not significantly different though less variable (0.30+/-0.07; n=12). The observations suggest that exposure of the Bangladesh population to As contained in rice is less of an immediate concern than the continued use of groundwater containing elevated As levels for drinking or cooking, or other potential consequences of As accumulation in soil and soil-water.

The risk of breast cancer recurrence in the sentinel lymph node era

10600

Background: Sentinel lymph node biopsy (SLNB), the preferred method of axillary staging in early breast cancer, is more sensitive and accurate compared to axillary node dissection. However, this data has not been incorporated into current prognostic models estimating the risk of breast cancer recurrence. We hypothesize that prognostic models based on data in the pre-SLN era underestimate survival and exaggerate benefits resulting from adjuvant therapy. In order to evaluate this hypothesis, we examined the disease free survival (DFS) and overall survival (OS) in an IRB approved, prospective, multicenter study of SLNB. Methods: From 1996–2005, 564 patients who had invasive disease in whom a SLN was found were examined from two experienced sites . Data was analyzed with regards to SLN status, tumor size, grade, lymphovascular invasion (LVI), age, estrogen receptor (ER) status and use of chemotherapy with respect to DFS and OS. Results: Median age was 57 years, tumor size was 1.5 (range 0.08–10.5) cm and follow-up was 46.2 (range 1–104.5) months. The SLN was positive in 31.2% of patients. The Kaplan-Meier (K-M) 5 year estimate of OS was 94.5(±1)% and DFS 88(±2)%. Tumor grade and size, LVI, ER- and +SLN significantly correlated with poorer DFS and OS by univariate analysis. By multivariate analysis, however, SLN status was the only statistically significant predictor for DFS (p = 0.004; HR = 3.4; CI = 1.5 - 8.0) and OS (p = 0.0051; HR = 7.3; CI = 1.8–29.4). SLN negative patients showed K-M 5 year DFS and OS estimates of 94(±)% and 97.4(±1)% respectively. There was no significant difference in DFS for SLN- patients treated with or without chemotherapy (p = 0.3). Conclusions: SLN status was the only significant predictor of DFS and OS. In node negative patients, we observed a higher DFS and OS than current statistical models based on historical data would have predicted. In this new era of SLNB, the magnitude of benefit from adjuvant therapy in sentinel node negative patients should be re-evaluated.

No significant financial relationships to disclose.

Identification of discrete chromosomal deletion by binary recursive partitioning of microarray differential expression data

DNA copy number abnormalities (CNA) are characteristic of tumours, and are also found in association with congenital anomalies and mental retardation. The ultimate impact of copy number abnormalities is manifested by the altered expression of the encoded genes. We previously developed a statistical method for the detection of simple chromosomal amplification using microarray expression data. In this study, we significantly advanced those analytical techniques to allow detection of localised chromosomal deletions based on differential gene expression data. Using three cell lines with known chromosomal deletions as model system, mRNA expression in those cells was compared with that observed in diploid cell lines of matched tissue origin. Results show that genes from deleted chromosomal regions are substantially over-represented (p<0.000001 by chi2) among genes identified as underexpressed in deletion cell lines relative to normal matching cells. Using a likelihood based statistical model, we were able to identify the breakpoint of the chromosomal deletion and match with the karyotype data in each cell line. In one such cell line, our analyses refined a previously identified 10p chromosomal deletion region. The deletion region was mapped to between 10p14 and 10p12, which was further confirmed by subtelomeric fluorescence in situ hybridisation. These data show that microarray differential expression data can be used to detect and map the boundaries of submicroscopic chromosomal deletions.

Limited temporal variability of arsenic concentrations in 20 wells monitored for 3 years in Araihazar, Bangladesh

Millions of people in Bangladesh have probably switched their water consumption to wells that meet the local standard for As in drinking water of 50 microg/L as a result of blanket field testing throughout the country. It is therefore important to know if As concentrations in those wells could change over time. To address this issue, we report here precise groundwater As analyses for time-series samples collected from a suite of 20 tube wells containing < or =50 microg/L As and ranging from 8 to 142 m in depth. For 17 out of 20 wells, the standard deviation of groundwater As concentrations was <10 microg/L over the 3-year monitoring period (n = 24-44 per well). Six of the 17 wells are community wells, each of which serves the needs of several hundred people in particularly affected villages. Of the three wells showing larger fluctuations in chemical composition including As, two are very shallow (8 and 10 m). Variations in As concentrations for one of these wells (50 +/- 32 microg/L, n = 36), as well as another shallow well showing smaller variations (48 +/- 5 microg/L, n = 36), appear to be coupled to seasonal precipitation and recharge linked to the monsoon. The other shallow well showing larger variations in composition indicates a worrisome and steady increase in As concentrations from 50 to 70 microg/L (n = 36) over 3 years. The time series of As (30 +/- 11 microg/L, n = 24) and other constituents in one deep community well (59 m) show large fluctuations that suggest entrainment of shallow groundwater through a broken PVC pipe. Even though the majority of wells that were initially safe remained so for 3 years, our results indicate that tube wells should be tested periodically.

Potential for improving bioavailable zinc in wheat grain (Triticum species) through plant breeding

A "whole-body" radioassay procedure was used to assess retention and absorption by rats of Zn in mature kernels of whole grain wheat harvested from 28 genotypes (Triticum spp.) grown in nutrient solution supplied with 2 microM ZnSO4 radiolabeled with 65Zn. Grain-Zn concentration differed among genotypes and ranged from 33 to 149 microg g(-1) of dry weight (DW); similarly, grain-Fe concentration varied approximately 4-fold, from 80 to 368 microg g(-1) of DW. Concentrations of Zn and Fe in the grain were positively correlated. Therefore, selecting genotypes high in grain-Zn also tends to increase grain-Fe concentration. Concentrations of myo-inositolhexaphosphate (phytate) in the wheat grain varied from 8.6 to 26.1 micromol g(-1) of DW. Grain intrinsically labeled with 65Zn was incorporated into test meals fed to Zn-depleted rats. All rats readily ate the test meals, so that Zn intake varied directly with grain-Zn concentration. As determined by the percentage of 65Zn absorbed from the test meal, the bioavailability to rats of Zn in the wheat genotypes ranged from about 60 to 82%. The amount of bioavailable Zn (micrograms) in the grain was positively correlated to the amount of Zn accumulated in the grain. There was a significant negative correlation between grain-phytate levels and percentage of Zn absorbed from the wheat grain, but the effect was not large. These results demonstrate that concentrations of Zn in whole-wheat grain, as well as amounts of bioavailable Zn in the grain, can be increased significantly by using traditional plant-breeding programs to select genotypes with high grain-Zn levels. Increasing the amount of Zn in wheat grain through plant-breeding contrivances may contribute significantly to improving the Zn status of individuals dependent on whole grain wheat as a staple food.

Raised dietary n-6 polyunsaturated fatty acid intake increases 2-series prostaglandin production during labour in the ewe

Preterm labour is the major cause of perinatal morbidity and mortality in humans. The incidence is around 10% and the causes are often unknown. Consumption of dietary n-6 polyunsaturated fatty acids (PUFAs) in western societies is increasing. These are metabolized to arachidonic acid, the precursor for 2-series prostaglandins (PGs), major signalling molecules during labour. This study investigated the effect of dietary supplementation with linoleic acid (LA, 18: 2, n-6) on parturition. Ewes were fed a control or LA-supplemented diet from 100 days gestation. Labour was induced using a standardized glucocorticoid challenge (dexamethasone, Dex) to the fetus, starting on day 139. Electromyographic (EMG) activity and fetal and maternal circulating PG concentrations were monitored. One third of LA-fed ewes delivered early (pre-Dex) although basal uterine EMG activity preceding Dex was higher in control ewes (P < 0.05). A steep increase in EMG activity occurred 18-38 h after the start of Dex infusion. Twice basal EMG activity (defined as established labour) occurred on average 7 h earlier in the LA-supplemented ewes (P < 0.05). The basal concentrations of maternal and fetal PGFM and fetal PGE(2) were approximately doubled in LA-supplemented ewes before the start of Dex infusion (P < 0.01). The rise in fetal PGE(2) and maternal oestradiol concentrations post-Dex occurred earlier in the LA-supplemented ewes. All PG measurements remained significantly higher in the LA-supplemented ewes during labour onset. This study suggests that consumption of a high LA diet in late pregnancy can enhance placental PG production and may thus increase the risk of preterm labour.

The effect of a diet supplemented with the n-6 polyunsaturated fatty acid linoleic acid on prostaglandin production in early- and late-pregnant ewes

Polyunsaturated fatty acids derived from the diet are incorporated into cell membranes where they act as precursors for prostaglandin (PG) synthesis. Linoleic acid (LA; 18:2 n-6) is a major constituent of plant oils and its consumption in Westernized populations is increasing. This study investigated the influence of LA on PG production by the uterus and placenta. Pregnant ewes were fed a control or an LA-enriched diet. Oxytocin (OT) was injected on day 45 (early) or day 133 (late) of gestation to measure the release of 13,14-dihydro-15-keto PGF(2alpha) (PGFM). Ewes were killed on day 46 or day 138 for collection of uterine intercaruncular endometrium and fetal allantochorion. Basal and stimulated PG release from explant cultures was assessed before and after in vitro treatment with OT, lipopolysaccharide (LPS), dexamethasone (DEX) or calcium ionophore (CaI). Expression of cyclooxygenase (COX)-1 and COX-2 was determined by Western blot in endometrium of late-gestation ewes. Circulating PGFM levels in vivo did not differ according to diet but there were highly significant differences in the release of PGs in vitro. Basal production of PGF(2alpha)and PGE(2) by the endometrium and of PGE(2) by the allantochorion were all higher in tissues from LA-supplemented ewes. Endometrial tissues produced more PG following OT and CaI treatment, whereas DEX inhibited production of both PGs at both stages of gestation. In allantochorion collected at day 46 LPS did not significantly alter PGE(2) release and DEX increased output, whereas at day 138 LPS was stimulatory but DEX was inhibitory. These data show that a high-LA diet can significantly increase the ability of both endometrium and placental tissues to produce PGs in vitro. This effect of diet may only become apparent after a sustained period of PG release, so was not seen following the brief pulse caused by OT treatment in vivo. As COX protein levels were unaltered, the main influence was likely to be via conversion of LA to arachidonic acid, providing an increased supply of precursor. These results support previous studies which suggest that alterations in dietary polyunsaturated fatty acids may influence the time of labour.

Reliability of a commercial kit to test groundwater for arsenic in Bangladesh

A comparison of field and laboratory measurements of arsenic in groundwater of Araihazar, Bangladesh, indicates that the most widely used field kit correctly determined the status of 88% of 799 wells relative to the local standard of 50 microg/L As. Additional tests showthatthe inconsistencies, mainly underestimates in the 50-100 microg/L As range, can be avoided by increasing the reaction time from 20 to 40 min. Despite this limitation, the field data already compiled for millions of wells by the Bangladesh Arsenic Mitigation and Water Supply Project, in combination with information on well location and depth, should prove to be extremely useful to prioritize interventions in thousands of affected villages.

Testing groundwater for arsenic in Bangladesh before installing a well

Profiles of groundwater and sediment properties were collected at three sites in Bangladesh with an inexpensive sampling device that is deployed by modifying the local manual drilling method. Dissolved As concentrations in the groundwater samples ranging from 5 to 600 microg/L between 5 and 50 m depth closely matched vertical profiles from nearby nests of monitoring wells. In combination with a field kit, the device provides a means of targeting aquifers for the installation of tube wells that meet the drinking water standard for As. The device is also a useful research tool for unraveling the relationships between the As content of groundwater and the complex structure of flood plain and deltaic environments throughout South Asia.

Relationships between the plasma concentrations of insulin-like growth factor-I in dairy cows and their fertility and milk yield

The relationships between insulin-like growth factor-I (IGF-I) and the fertility and milk yield of Holstein-Friesian dairy cows were investigated. The concentration of IGF-I in blood was measured weekly from one week before to 12 weeks after calving in 177 multiparous cows and at four times during this period in 142 primiparous cows; the concentration of IGF-I in milk was measured in 50 of the multiparous cows. The plasma concentrations of IGF-I were higher in the primiparous than in the multiparous animals. In the primiparous cows, high concentrations of IGF-I before calving were associated with longer calving to conception intervals. Conversely, in the multiparous cows low concentrations of IGF-I before and after calving were associated with a failure to conceive, despite repeated services. Multiparous cows with IGF-I concentrations of greater than 25 ng/ml in the week after calving were 11 times more likely to conceive to first service than those with lower concentrations. Concentrations of IGF-I greater than 50 ng/ml at first service increased the likelihood of conception five-fold. Cows with higher peak milk yields had lower plasma concentrations of IGF-I and took longer to return to ovarian cyclicity. The negative relationship between milk yield and return to cyclicity was stronger in the multiparous cows (P < 0.002) than in the primiparous cows (P < 0.04). The concentrations of IGF-I in milk followed a different pattern and were not associated with the changes in plasma IGF-I or fertility.

Alteration of prostaglandin production and agonist responsiveness by n-6 polyunsaturated fatty acids in endometrial cells from late-gestation ewes

We investigated the effect of n-6 polyunsaturated fatty acids (PUFAs) on prostaglandin (PG) production by the uterus. A mixed population of endometrial cells (epthelium and stroma) from late-gestation ewes were cultured in defined medium containing linoleic acid (LA, 18:2, n-6), gamma-linolenic acid (GLA, 18:3, n-6) or arachidonic acid (AA, 20:4, n-6) in concentrations of 0 (control), 20 or 100 microM. After 45 h in test medium with or without added PUFAs, cells were challenged with control medium (CM), oxytocin (OT, 250 nM), lipopolysaccharide (LPS, 0.1 micro g/ml) or dexamethasone (DEX, 5 microM) for 22 h in the continued presence of the same concentration of PUFA and the medium was collected for measurement of PGF(2alpha) and PGE(2). Supplementation with LA inhibited the production of PGF(2alpha) but did not alter PGE(2), whereas GLA and AA increased production of both PGs. All PUFA supplements thus increased the ratio of PGE(2) to PGF(2alpha) (E:F ratio) two- to threefold. In control cells, OT and LPS challenges stimulated the production of PGF(2alpha) and PGE(2). In all challenge groups, the concentrations of PGF(2alpha) in response to PUFAs followed the same pattern - LA<control<GLA<AA - but there were significant alterations in responsiveness as a result of PUFA treatment. In the cells supplemented with 100 microM AA, there was no further increase in PGF(2alpha) output in the presence of OT or LPS and when 100 microM GLA was present neither LPS nor OT stimulated PGE(2) significantly. When LPS was given to AA-supplemented cells, the E:F ratio was increased. DEX did not change PGE(2) production in control or LA-treated cells, but the cells produced significantly less PGF(2alpha), so the E:F ratio was increased. In contrast, in GLA- and AA-treated cells, DEX reduced the production of both PGF(2alpha) and PGE(2), so the E:F ratio was unaltered. In summary, the study showed altered production of PGs in the presence of different PUFAs according to their position in the n-6 metabolic pathway. The type of PUFA present affected responsiveness to OT, LPS and DEX and also changed the ratio of PGE(2) to PGF(2alpha) produced. The possible implications of this work are discussed in relation to the effect of diet on term and pre-term labour, which both require upregulation of the endometrial PG synthetic pathway.

Laparoscopic versus open total mesorectal excision with anal sphincter preservation for low rectal cancer

BACKGROUND

The Laparoscopic approach has been applied to colorectal surgery for many years; however, there are only a few reports on laparoscopic low and ultralow anterior resection with construction of coloanal anastomosis. This study compares open versus laparoscopic low and ultralow anterior resections, assesses the feasibility and efficacy of the laparoscopic approach of total mesorectal excision (TME) with anal sphincter preservation (ASP), and analyzes the short-term results of patients with low rectal cancer.

METHODS

We analyzed our experience via a prospective, randomized control trail. From June 2001 to September 2002, 171 patients with low rectal cancer underwent TME with ASP, 82 by the laparoscopic procedure and 89 by the open technique. The lowest margin of tumors was below peritoneal reflection and 1.5-8 cm above the dentate line (1.5-4.9 cm in 104 cases and 5-8 cm in 67 cases). The grouping was randomized.

RESULTS

Results of operation, postoperative recovery, and short-term oncological follow-up were compared between 82 laparoscopic procedures and 89 controls who underwent open surgery during the same period. In the laparoscopic group, 30 patients in whom low anterior resection was performed had the anastomosis below peritoneal reflection and more than 2 cm above the dentate line, 27 patients in whom ultralow anterior resection was performed had anastomotic height within 2 cm of the dentate line, and 25 patients in whom coloanal anastomosis was performed had the anastomosis at or below the dentate line. In the open group, the numbers were 35, 27, and 27, respectively. There was no statistical difference in operation time, administration of parenteral analgesics, start of food intake, and mortality rate between the two groups. However, blood loss was less, bowel function recovered earlier, and hospitalization time was shorter in the laparoscopic group.

CONCLUSION

Totally laparoscopic TME with ASP is feasible, and it is a minimally invasive technique with the benefits of much less blood loss during operation, earlier return of bowel function, and shorter hospitalization.

Rapid multi-element analysis of groundwater by high-resolution inductively coupled plasma mass spectrometry

A rapid and sensitive method was developed to determine, with a single dilution, the concentration of 33 major and trace elements (Na, Mg, Si, K, Ca, Li, Al, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, In, Sn, Sb, Cs, Ba, Re, Hg, Pb, Bi, U) in groundwater. The method relies on high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) and works across nine orders of magnitude of concentrations. For most elements, detection limits for this method are considerably lower than methods based on quadrupole ICP-MS. Precision was within or close to +/-3% (1 sigma) for all elements analyzed, with the exception of Se (+/-10%) and Al (+/-6%). The usefulness of the method is demonstrated with a set of 629 groundwater samples collected from tube wells in Bangladesh (Northeast Araiharzar). The results show that a majority of tube well samples in this area exceed the WHO guideline for As of 10 microg L(-1), and that those As-safe wells frequently do not meet the guideline for Mn of 500 microg L(-1) and U of 2 microg L(-1).

GNB3 gene C825T and ACE gene I/D polymorphisms in essential hypertension in a Kazakh genetic isolate

The Kazakh inhabitants living in Barkol pasture of northeast China belong to a genetic isolate characterized by ethnically homogeneous and a communal pastoral lifestyle. To investigate whether the polymorphisms in the G-protein beta-3 subunit (GNB3) gene and angiotensin-converting enzyme (ACE) gene are associated with essential hypertension (EH), we carried out a case-control study of 290 hypertensive subjects and 244 normotensive (NT) controls randomly selected from Kazakh populations of Barkol. A previous medical history of diabetes and hypertension, and body mass index (BMI) was recorded. Plasma glucose, triglyceride, and cholesterol were measured. The insertion/deletion (I/D) polymorphism of the ACE gene and the C825T polymorphism of the GNB3 gene were determined by the polymerase chain reaction (PCR) technique. The distributions of genotypes and alleles for the two polymorphisms did not differ significantly between the case and control populations, and odds ratio of EH related to the ACE gene D allele and GNB3 gene T allele was not significantly different from 1.0. Logistic regression analysis shows the variation at the GNB3 and ACE did not have any statistically significant synergistic effect on blood pressure (BP). Stratification of NT and untreated hypertensives according to I/D polymorphism of ACE gene and C825T polymorphism of GNB3 gene disclosed no significant difference across genotypes with respect to BMI, glucose, triglyceride, cholesterol, systolic and diastolic BP. In conclusion, the polymorphisms in the GNB3 gene and ACE gene, solely or combined, did not confer a significantly increased risk for the development of EH in the Kazakh isolate of northeast China.

Intermittent hypoxic exposure during light phase induces changes in cAMP response element binding protein activity in the rat CA1 hippocampal region: water maze performance correlates

Intermittent hypoxia (IH) during sleep, a characteristic feature of sleep-disordered breathing (SDB) is associated with time-dependent apoptosis and spatial learning deficits in the adult rat. The mechanisms underlying such neurocognitive deficits remain unclear. Activation of the cAMP-response element binding protein (CREB) transcription factor mediates critical components of neuronal survival and memory consolidation in mammals. CREB phosphorylation and DNA binding, as well as the presence of apoptosis in the CA1 region of the hippocampus were examined in Sprague-Dawley male rats exposed to IH. Spatial reference task learning was assessed with the Morris water maze. IH induced significant decreases in Ser-133 phosphorylated CREB (pCREB) without changes in total CREB, starting as early as 1 h IH, peaking at 6 h-3 days, and returning toward normoxic levels by 14-30 days. Double-labeling immunohistochemistry for pCREB and Neu-N (a neuronal marker) confirmed these findings. The expression of cleaved caspase 3 (cC3) in the CA1, a marker of apoptosis, peaked at 3 days and returned to normoxic values at 14 days. Initial IH-induced impairments in spatial learning were followed by partial functional recovery starting at 14 days of IH exposure. We postulate that IH elicits time-dependent changes in CREB phosphorylation and nuclear binding that may account for decreased neuronal survival and spatial learning deficits in the adult rat. We suggest that CREB changes play an important role in the neurocognitive morbidity of SDB patients.

Effects of conjugated linoleic acid on prostaglandins produced by cells isolated from maternal intercotyledonary endometrium, fetal allantochorion and amnion in late pregnant ewes

The anticarcinogenic properties of conjugated linoleic acid (CLA) are, at least partially, attributed to its ability to interrupt the n-6 polyunsaturated fatty acid (PUFA) metabolic pathway for the biosynthesis of eicosanoids, including prostaglandins (PG). Both PGE(2) and PGF(2alpha) play key roles in parturition. In the present study, we compared the effects of CLA (a mixture of cis- and trans-9, 11- and -10, 12-octadecadienoic acid) and linoleic acid (LA) on PG production by cells isolated from maternal intercotyledonary endometrium, fetal allantochorion and amnion from late pregnant ewes. The results demonstrated that supplementation of LA and CLA significantly affected both the proportions and the amounts of PGs produced by all three tissue types. The ability of the uterus and placenta to respond to oxytocin (OT, endometrium only) and lipopolysaccharide (LPS) was also affected. LA inhibited PGE(2) and PGF(2alpha) production in the absence or presence of either oxytocin or LPS. In endometrial cells with or without oxytocin or LPS, CLA dose-dependently suppressed PGF(2alpha) generation, whereas low doses of CLA (20 microM) increased PGE(2) generation. Supplementation with CLA therefore increased the PGE(2)/PGF(2alpha) ratio in the endometrial cells. These results suggest that dietary supplementation of LA or CLA may affect both the initiation and progression of parturition.

Iron and zinc absorption from two bean (Phaseolus vulgaris L.) genotypes in young women

Extrinsic and intrinsic iron and zinc labels were used to test iron and zinc absorption from two bean (Phaseolus vulgaris) genotypes, containing normal (common beans, CB) or higher (HFeZnB) iron and zinc concentrations, fed in single meals to young women with low iron reserves. The women were divided into two groups, with one receiving a CB test meal (n = 12) and the other, an HFeZnB test meal (n = 11). The beans were intrinsically labeled hydroponically with (55)Fe (CB and HFeZnB) and with (70)Zn (HFeZnB). Concentrations of zinc and iron were 98 and 65% higher, respectively, in HFeZnB as compared to CB, but phytic acid contents were similar. Extrinsic labels were (59)Fe (CB and HFeZnB), (67)Zn (CB), and (68)Zn (HFeZnB). Iron and zinc percent absorption levels were calculated from radio-iron activity in red blood cells and from urinary excretion of zinc isotopes. Intrinsic and extrinsic iron absorption measures were highly correlated (R (2) = 0.986) (average extrinsic/intrinsic ratio was 1.00). Iron absorption was low (geometric mean < 2%) in both bean types, and total iron absorbed was not different between types. Intrinsic zinc absorption from the HFeZn beans was higher than extrinsic absorption (15.2% vs 13.4%, p < 0.05) (average extrinsic/intrinsic was 0.90). The correlation between intrinsic and extrinsic zinc measures was not as high as that for iron (R (2) = 0.719). Percent zinc absorption levels were similar in both bean types, but total extrinsic zinc absorbed was 90% higher (p < 0.05) from the HFeZnB meal. Thus, the less expensive and time-consuming extrinsic labeling may be used to screen various varieties of beans for iron bioavailability in humans, but it underestimates zinc absorption by approximately 10%. Selective breeding for high-zinc bean genotypes may improve zinc status. However, high-iron genotypes appear to have little effect on iron status when fed alone in single meals to women with low iron reserves.

Rotational diffusion microrheology

Examining the rotational diffusion of a microparticle suspended in a soft material opens up exciting new opportunities for locally probing the frequency-dependent linear viscoelastic shear modulus, G*(omega). We study the one-dimensional rotational diffusion of a wax microdisk in an aqueous polymer entanglement network using light streak tracking. By measuring the disk's time-dependent mean square angular displacement, <Delta theta(2)(t)>, we predict the polymer solution's G*(omega) using a rotational generalized Stokes-Einstein relation. The good agreement of the predicted modulus with mechanical measurements confirms this new microrheological approach.

Follicle growth, corpus luteum function and their effects on embryo development in postpartum dairy cows

Absent or irregular ovarian cycles in lactating dairy cows are caused by failure to ovulate the dominant follicle at the appropriate time. The follicle then either regresses or develops into a cyst. This process can be triggered by a variety of metabolic and disease factors that act at the hypothalamus and pituitary gland to inhibit pulsatile LH secretion and the LH surge, and at the ovary to reduce follicular growth and oestradiol production. Cows of poor energy status have low circulating concentrations of insulin-like growth factor I (IGF-I). Predisposing factors include calving difficulties, inappropriate diet, reduced intake of dry matter and a high rate of body condition score loss. Various stressors predispose the follicle to cyst development by inhibiting the LH surge and ovulation; these include common infections, such as mastitis. Even when ovulation does occur, poor follicular development may result in production of an inadequate corpus luteum. The timing of the increase in progesterone in the early luteal phase (days 4-5) appears to be a key determinant of fertility, probably because it alters the secretory activity of the reproductive tract, thus influencing embryonic growth and interferon-tau production. A period of negative energy balance after calving can reduce fertility even though metabolic parameters have apparently improved at the time of service.

Light streak tracking of optically trapped thin microdisks

Nonspherical particles can uniquely probe soft system dynamics. We show that laser tweezers stably trap thin coinlike microdisks in 3D with an edge-on orientation. Scattered light forms a streak that we track using a fast camera to measure the disk's angular displacement. Linearly polarized tweezers rotationally trap a birefringent disk, and we measure its harmonically bound Brownian rotation over 5 decades in time. Near a surface, the disk exhibits a translational-orientational switchback oscillation. Circularly polarized tweezers rotate the disk and streak, yielding a colloidal lighthouse.

[Experimental study of oxygen supply and demand balance during total hepatectomy and partial liver replantation with venous bypass technique in young pigs]

OBJECTIVE

To investigate the changes of oxygen supply and demand balance during total hepatectomy and partial liver replantation(TCH and PLRP) with venous bypass technique in pigs.

METHODS

Seven young pigs[weight (24.2 +/- 4.8) kg] were anesthetized with fentanyl and pentobartal. Catheters were inserted into portal vein via splenic vein and into vena cava inferior via right femoral vein, respectively, and the two catheters were connected by a "Y" adaptor to right atrium via extracorporeal circulation pump. Venous bypass technique was used during occlusion of total hepatic blood stream(OTHB). SvO2, hemodynamics and blood gas analysis were measured after anesthesia, during and 30 minutes after venous bypass.

RESULTS

SvO2 was decreased significantly(P < 0.05), vein bypass technique ameliorated partially the disturbance of hemodynamics, and there was correlation between CO and SvO2 during THC and PLRP in pigs.

CONCLUSION

The results suggest that there is oxygen supply and demand unbalance during THC and PLRP with venous bypass technique in pigs, and it is beneficial to monitor oxygen ladder during operation.

Genome sequencing of a 239-kb region of rice chromosome 10L reveals a high frequency of gene duplication and a large chloroplast DNA insertion

In this study we describe a 239-kb region on the long arm of rice chromosome 10 that contains a high density (71%) of locally duplicated genes, including 24 copies of a glutathione S-transferase gene. Intriguingly, embedded within this cluster is a large insertion (approximately 33 kb) of rice (Oryza sativa) chloroplast DNA that is derived from two separate regions of the chloroplast genome. We used DNA fiber-based fluorescence in situ hybridization (fiber-FISH) analyses of O. sativa spp. japonica nuclei to confirm that the insertion of organellar DNA was not a cloning artifact. The sequence of the chloroplast insertion is nearly identical (99.7% identity) to the corresponding regions in the published rice chloroplast genome sequence, suggesting that the transfer event occurred recently. PCR amplification and sequence analysis in two subspecies of rice, O. sativa spp. japonica and spp. indica, indicates that the transfer event predated the divergence of these two subspecies. The chloroplast insertion is flanked by a 2.1-kb perfect direct repeat that is unique to this location in the rice genome.

Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows

Alteration of the polyunsaturated fatty acid (PUFA) composition of milk by dietary supplementation of cows may be beneficial to human health. However, dietary PUFAs may influence synthesis of both prostaglandins and steroid hormones. This study examined the effects of dietary PUFAs on reproductive parameters in lactating cows. Cows were fed an isoenergetic control ration (n = 8) or a diet supplemented with LinPreme (n = 7) or SoyPreme (n = 8). These proprietary feeds are derived from linseed or soybeans and contain high concentrations of linolenic acid (LNA, n-3) or linoleic acid (LA, n-6) protected PUFA, respectively. Both PUFA-supplemented diets reduced plasma progesterone, particularly in the early luteal phase, and increased the number of medium-sized (5-10 mm in diameter) follicles. The diameter of the first dominant follicle, insulin-like growth factor I (IGF-I) concentrations at oestrus and cholesterol concentrations were all higher in cows fed a diet supplemented with LA (n-6) than in cows that did not receive this supplement. In cows fed a diet supplemented with LNA (n-3), there was an increase in oestradiol during the follicular phase. Diet had no effect on non-esterified fatty acid or insulin concentrations, or on the duration of the oestrous cycle. The plasma concentration of 13,14,dihydro-15 keto PGF(2alpha) after administration of 50 iu oxytocin was unaffected by diet on day 15 and day 16 of the oestrous cycle, but showed a greater response on day 17 in the LA (n-6) supplemented group. Therefore, the PUFA content of the diet can influence both ovarian and uterine function in cows. However, further studies using larger numbers of cows are required to test whether fertility is also affected by such diets.

Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows

Alteration of the polyunsaturated fatty acid (PUFA) composition of milk by dietary supplementation of cows may be beneficial to human health. However, dietary PUFAs may influence synthesis of both prostaglandins and steroid hormones. This study examined the effects of dietary PUFAs on reproductive parameters in lactating cows. Cows were fed an isoenergetic control ration (n = 8) or a diet supplemented with LinPreme (n = 7) or SoyPreme (n = 8). These proprietary feeds are derived from linseed or soybeans and contain high concentrations of linolenic acid (LNA, n-3) or linoleic acid (LA, n-6) protected PUFA, respectively. Both PUFA-supplemented diets reduced plasma progesterone, particularly in the early luteal phase, and increased the number of medium-sized (5-10 mm in diameter) follicles. The diameter of the first dominant follicle, insulin-like growth factor I (IGF-I) concentrations at oestrus and cholesterol concentrations were all higher in cows fed a diet supplemented with LA (n-6) than in cows that did not receive this supplement. In cows fed a diet supplemented with LNA (n-3), there was an increase in oestradiol during the follicular phase. Diet had no effect on non-esterified fatty acid or insulin concentrations, or on the duration of the oestrous cycle. The plasma concentration of 13,14,dihydro-15 keto PGF(2alpha) after administration of 50 iu oxytocin was unaffected by diet on day 15 and day 16 of the oestrous cycle, but showed a greater response on day 17 in the LA (n-6) supplemented group. Therefore, the PUFA content of the diet can influence both ovarian and uterine function in cows. However, further studies using larger numbers of cows are required to test whether fertility is also affected by such diets.

A bacterial artificial chromosome (BAC) library of Malus floribunda 821 and contig construction for positional cloning of the apple scab resistance gene Vf

The apple scab resistance gene Vf, originating from the wild species Malus floribunda 821, has been incorporated into a wide variety of apple cultivars through a classical breeding program. With the aim of isolating the Vf gene, a bacterial artificial chromosome (BAC) library consisting of 31 584 clones has been constructed from M. floribunda 821. From the analysis of 88 randomly selected BAC clones, the average insert size is estimated at 125 kb. If it is assumed that the genome size of M. floribunda 821 is 769 Mb/haploid, the library represents about 5x haploid genome equivalents. This provides a 99% probability of finding any specific sequence from this library. PCR-based screening of the library has been carried out using eight random genomic sequence-characterized amplified regions (SCARs), chloroplast- and mitochondria-specific SCARs, and 13 high-density Vf-linked SCAR markers. An average of five positive BAC clones per random SCAR has been obtained, whereas less than 1% of BAC clones are derived from the chloroplast or mitochondrial genomes. Most BAC clones identified with Vf-linked SCAR markers are physically linked. Three BAC contigs along the Vf region have been obtained by assembling physically linked BAC clones based on their fingerprints. The overlapping relatedness of BAC clones has been further confirmed by cytogenetic mapping using fiber fluorescence in situ hybridization (fiber-FISH). The M. floribunda 821 BAC library provides a valuable genetic resource not only for map-based cloning of the Vf gene, but also for finding many other important genes for improving the cultivated apple.

Toward a cytological characterization of the rice genome

Rice (Oryza sativa L.) will be the first major crop, as well as the first monocot plant species, to be completely sequenced. Integration of DNA sequence-based maps with cytological maps will be essential to fully characterize the rice genome. We have isolated a set of 24 chromosomal arm-specific bacterial artificial chromosomes to facilitate rice chromosome identification. A standardized rice karyotype was constructed using meiotic pachytene chromosomes of O. sativa spp. japonica rice var. Nipponbare. This karyotype is anchored by centromere-specific and chromosomal arm-specific cytological landmarks and is fully integrated with the most saturated rice genetic linkage maps in which Nipponbare was used as one of the mapping parents. An ideogram depicting the distribution of heterochromatin in the rice genome was developed based on the patterns of 4',6-diamidino-2-phenylindole staining of the Nipponbare pachytene chromosomes. The majority of the heterochromatin is distributed in the pericentric regions with some rice chromosomes containing a significantly higher proportion of heterochromatin than other chromosomes. We showed that pachytene chromosome-based fluorescence in situ hybridization analysis is the most effective approach to integrate DNA sequences with euchromatic and heterochromatic features.

Effect of dietary polyunsaturated fatty acids on uterine prostaglandin synthesis in the cow

Dietary polyunsaturated fatty acid (PUFA) intake in humans can affect the incidence of a variety of diseases including coronary heart disease. Feeding high PUFA diets to cows can alter the PUFA content of milk for human consumption. PUFAs supply the precursors for prostaglandin (PG) synthesis and PGs in turn influence many aspects of reproduction. This study examined the effects of a control (CONT), a high n-6 PUFA diet (derived from protected soya) and a high n-3 diet (derived from protected linseed) on uterine PG synthesis in the lactating dairy cow. Endometrial explants obtained on days 15-17 of the oestrous cycle were cultured for an initial 42 h in vitro in fully defined medium (basal production) and then challenged with control medium, oxytocin (OT; 20 or 200 nM) or calcium ionophore A23187 (CaI; 10 microM). PGF(2 alpha), PGE(2) and 6-keto-PGF(1 alpha) were measured in the spent medium. The experiments were repeated using tissue from two groups of cows, nine in Experiment 1 (three cows per diet) and seven in Experiment 2 (four CONT and three n-6). Results of the two experiments were consistent. The basal concentrations of all three PGs were significantly lower (>50% reduction) in the n-6-fed group in comparison with CONT and n-3 groups. The n-3 diet did not alter basal PGF(2 alpha) and PGE(2) but increased 6-keto-PGF(1 alpha). The n-6 diet also inhibited the ability of the tissue to respond to both OT and CaI, with significant reductions in the stimulated levels of all three PGs. In contrast, the n-3 diet only had minor effects; it did not alter the response to OT but did reduce the long-term response to CaI at 24 h post treatment. In conclusion, dietary PUFA intake can inhibit PG production in bovine endometrial explants, with a more pronounced effect following n-6 rather than n-3 supplementation. These data suggest that a high n-6 diet reduces the endometrial capacity to produce PGs and may therefore have implications for the control of luteolysis and other PG-mediated events such as ovulation.

Evaluation of an (111)In-DOTA-rhenium cyclized alpha-MSH analog: a novel cyclic-peptide analog with improved tumor-targeting properties

The aim of this study was to examine the effect of rhenium-mediated peptide cyclization on melanoma targeting, biodistribution, and clearance kinetics of the alpha-melanocyte-stimulating hormone (alpha-MSH) analog 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) coupled ReO-cyclized [Cys(3,4,10),D-Phe(7)]alpha-MSH(3-13) (DOTA-ReCCMSH).

METHODS

DOTA-ReCCMSH was compared with its reduced nonmetalated linear homolog, DOTA-CCMSH, and an analog in which rhenium cyclization was replaced by disulfide bond cyclization, DOTA-[Cys(4,10),D-Phe(7)]alpha-MSH(4-13) (CMSH). DOTA was also conjugated to the amino terminus of one of the highest-affinity alpha-MSH receptor-binding peptides, [Nle(4),D-Phe(7)]alpha-MSH (NDP), as a linear peptide standard. The DOTA-conjugated alpha-MSH analogs were radiolabeled with (111)In and examined for their in vitro receptor-binding affinity with B16/F1 murine melanoma cells, and their in vivo biodistribution properties were evaluated and compared in melanoma tumor-bearing C57 mice.

RESULTS

The tumor uptake values of (111)In-DOTA-ReCCMSH were significantly higher than those of the other closely related (111)In-DOTA-alpha-MSH conjugates. Even at 24 h after injection, a comparison of the tumor uptake values for (111)In-DOTA-coupled ReCCMSH (4.86 +/- 1.52 percentage injected dose [%ID]/g), CCMSH (1.91 +/- 0.56 %ID/g), CMSH (3.09 +/- 0.32 %ID/g), and NDP (2.47 +/- 0.79 %ID/g) highlighted the high tumor retention property of ReCCMSH. Rhenium-coordinated cyclization resulted in less renal radioactivity accumulation of (111)In-DOTA-ReCCMSH (8.98 +/- 0.82 %ID/g) than of (111)In-DOTA-CCMSH (63.2 +/- 15.6 %ID/g), (111)In-DOTA-CMSH (38.4 +/- 3.6 %ID/g), and (111)In-DOTA-NDP (12.0 +/- 1.96 %ID/g) at 2 h after injection and significantly increased its clearance into the urine (92 %ID at 2 h after injection). A high radioactivity uptake ratio of tumor to normal tissue was obtained for (111)In-DOTA-ReCCMSH (e.g., 489, 159, 100, and 49 for blood, muscle, lung, and liver, respectively, at 4 h after injection).

CONCLUSION

The novel ReO-coordinated cyclic structure of DOTA-ReCCMSH contributes significantly to its enhanced tumor-targeting and renal clearance properties and makes DOTAReCCMSH an excellent candidate for melanoma radiodetection and radiotherapy.

[Study on history of cosmopolitan medicine in China]

Roughly, three stages may be differentiated in the studies on the history of cosmopolitan medicine in China. The first stage (1907-1949) is mainly focussed on the translation of articles on medical history from abroad, mostly for popularization of the knowledge on medical history. The second stage (1950-1979), like the first stage, is a stage of translation of papers on medical history from foreign countries, mainly the USSR and Eastern European countries. The third stage (1980-1995) deals with, in addition to translation, studies on special topics with increasing coverage for investigation.

Temporal and spatial expression patterns of TUB9, a beta-tubulin gene of Arabidopsis thaliana

Transgenic plants carrying chimeric genes composed of segments of the 5'-flanking region of the Arabidopsis 9-tubulin gene (TUB9) fused to the coding region of the beta-glucuronidase (GUS) gene of Escherichia coli were used to investigate the temporal and spatial patterns of TUB9 expression. Chimeric genes that contained at least 800 bp of TUB9 5'-flanking DNA were expressed primarily in floral tissues, with high levels of expression observed in pollen, elongating pollen tubes and ovules. The expression of the reporter genes in ovules ceased at the time of fertilization. In situ hybridization was used to verify that the reporter gene expression in pollen of transgenic plants is representative of the patterns of expression of the endogenous TUB9 gene. In situ hybridization also provided new insight into TUB9 transcript accumulation in ovules. The possible role of TUB9 and the functional implication of the largely non-overlapping expression patterns of tubulin genes are discussed.

Temperature distributions and thermal deformations of mirror substrates in laser resonators

For finite-thickness media with convective surface losses, the three-dimensional temperature distributions and thermal deformations of mirror substrates in laser resonators that are due to absorption of laser light with a Gaussian power-density profile are calculated by use of the well-known Green's function methods. Some expressions and theoretical profiles of the temperature distributions and thermal deformations as functions of the radius and the thickness of a mirror substrate are obtained. The results of the calculations show that the rise in temperature is closely related to the absorption coefficient of the medium as well as to the convective heat-transfer coefficient, that the initial thermal deformations of mirror surfaces increase quickly at the beginning of laser heating and that then the thermal deformations are insensitive to laser heating times. Meanwhile, thermal deformations of a silicon mirror are experimentally demonstrated by use of CO(2) laser irradiation. The experimental trends of thermal deformations are in agreement with the theoretical profiles.

[HPLC determination of oleanolic acid and llrolic acid in Chinese medicinal herbs]

OBJECTIVE

To develop a new method for simultaneous determination of oleanolic acid and llrolic acid in Chinese medicinal herbs at the same time.

METHOD

HPLC was carried out on a Shim-pack CLC-ODS column using MeOH-H2O-HOAc-TEA (83:17:0.04:0.02).

RESULT AND CONCLUSION

The average recovery of oleanolic acid and llrolic acid was 103.3 +/- 2.07% and 102.7% +/- 0.65% respectively.

Colloidal hard-sphere crystallization kinetics in microgravity and normal gravity

The hard-sphere disorder-order transition serves as the paradigm for crystallization. We used time-resolved Bragg light scattering from the close-packed planes to measure the kinetics of nucleation and growth of colloidal hard-sphere crystals. The effects of gravity are revealed by comparison of the experiments in microgravity and normal gravity. Crystallites grow faster and larger in microgravity, and the coarsening between crystallites is suppressed by gravity. The face-centered-cubic structure was strongly indicated as being the stable structure for hard-sphere crystals. For a sample with a volume fraction of 0.552, the classic nucleation and growth picture is followed.

Amplification of antigen-antibody interactions based on biotin labeled protein-streptavidin network complex using impedance spectroscopy

Antibody was covalently immobilized by amine coupling method to gold surfaces modified with a self-assembled monolayer of thioctic acid. The electrochemical measurements of cyclic voltammetry and impedance spectroscopy showed that the hexacyanoferrate redox reactions on the gold surface were blocked due to the procedures of self-assembly of thioctic acid and antibody immobilization. The binding of a specific antigen to antibody recognition layer could be detected by measurements of the impedance change. A new amplification strategy was introduced for improving the sensitivity of impedance measurements using biotin labeled protein-streptavidin network complex. This amplification strategy is based on the construction of a molecular complex between streptavidin and biotin labeled protein. This complex can be formed in a cross-linking network of molecules so that the amplification of response signal will be realized due to the big molecular size of complex. The results show that this amplification strategy causes dramatic improvement of the detection sensitivity of hIgG and has good correlation for detection of hIgG in the range of 2-10 microg/ml.