[Effectiveness of minimally invasive surgery in the treatment of pancreatic acinar cell carcinoma]

Objective: To explore the effectiveness of minimally invasive surgical treatment for pancreatic acinar cell carcinoma (PACC). Methods: Six patients with PACC diagnosed in Peking University Third Hospital from January 2010 to September 2022 were retrospectively selected. Preoperative evaluation was performed on whether the lesions were eligible for surgery, including whether radical resection of liver metastases could be performed. Laparoscopic or Da Vinci robot-assisted resection was performed on six patients, and spleen retention was determined according to the original lesions and the relationship with peripheral blood vessels and tissues, while simultaneous resection was performed on cases of peripheral organ tissue invasion. The patients' basic information, preoperative general conditions, preoperative diagnosis and tumor stage, minimally invasive surgery methods, postoperative complications, pathological results, tumor stage and follow-up data were collected and analyzed to explore the effectiveness of minimally invasive surgery. Results: Among the six patients, four were males and two were females, with the age of 25-69 years. Five patients had abdominal pain and distension before surgery, five patients had tumors located at the tail of the pancreatic body, and one patient had tumors located at the head of the pancreas. Preoperative imaging (enhanced CT and MRI) was performed to measure the tumor diameter (2.8-10.0 cm). Tumor markers were elevated in two patients before surgery, and six patients underwent surgery through laparoscopy or robotic platform. No complications such as postoperative pancreatic fistula and bleeding were clinically relevant during and after surgery. There were two cases with concurrent or heterochronous liver metastasis, two cases with lymph node metastasis and nodular metastasis, four cases with tumor invasion of surrounding organs (stomach, spleen or duodenum), and three cases with vascular cancer thrombi. The follow-up time of the six patients was 12 to 165 months, and one patient underwent three operations due to postoperative liver metastasis and residual pancreatic recurrence, and the results were satisfactory. All the six patients survived at the last follow-up. Conclusions: PACC is prone to invade the surrounding organs, and has a large tumor diameter. Radical surgery for PACC can be completed through minimally invasive surgery, and satisfactory oncology prognosis can be obtained. In addition, some PACC patients with recurrence and metastasis can still be treated by surgery.

[Association between unhealthy lifestyles and diabetic dyslipidemia in occupational population and network analysis]

Objective: To understand the influence of unhealthy lifestyle on diabetic dyslipidemia and the key influencing factors in occupational population and provided scientific evidence for the prevention of diabetic dyslipidemia. Methods: Based on baseline data and follow-up data of Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd. during 2021. Diabetic dyslipidemia was defined as diabetes plus one or more forms of dyslipidemia, and unhealthy lifestyle factors included smoking, alcohol consumption, unhealthy dietary patterns, low physical activity, and abnormal BMI. Multivariate logistic regression model was used to analyze the relationship between unhealthy lifestyle scores and diabetic dyslipidemia, network analysis was used to find and explore the key lifestyles influencing glycolipid metabolism. Results: A total of 25 631 subjects were included. People with unhealthy lifestyle score 2 and 3 were 1.93 (95%CI: 1.31-2.86) times and 2.37 (95%CI: 1.60-3.50) times more likely to have diabetes with ≥1 forms of dyslipidemia than those with scores of 0; People with unhealthy lifestyle score 1, 2 and 3 were 1.98 (95%CI: 1.08-3.61) times, 2.87 (95%CI: 1.60-5.14) times and 3.95 (95%CI: 2.22-7.06) times more likely to have diabetes with ≥2 forms of dyslipidemia than those with score 0. Network analysis found that abnormal BMI and HDL-C were the "bridge nodes" that link unhealthy lifestyles with diabetic dyslipidemia. Conclusion: The higher the score of unhealthy lifestyle, the higher the risk for diabetic dyslipidemia, abnormal BMI and HDL-C are key factors influencing the association between unhealthy lifestyle and diabetic dyslipidemia.

[Association between unhealthy lifestyles and hyperuricemia in occupational population and modification effect of hypertension and dyslipidemia]

Objective: To understand the relationship between unhealthy lifestyle and hyperuricemia, as well as the modification effects of hypertension and dyslipidemia in occupational population and provide a theoretical basis for the prevention of hyperuricemia. Methods: A cross-sectional survey design was adopted, based on baseline data from the Southwest Occupational Population Cohort from China Railway Chengdu Group Co., Ltd., which included the population in 28 prefectures from Sichuan Province and Guizhou Province, and 33 districts (counties) from Chongqing Municipality between October and December 2021. This study collected the information about the demographics characteristics, lifestyles, and prevalence of chronic non-communicable diseases of the study subjects through questionnaire, physical measurement and laboratory biochemical test. The unhealthy lifestyle score was scored based on smoking, alcohol consumption, dietary patterns, physical activity, and low weight or overweight, with higher scores being associated with more unhealthy lifestyles. The multivariate logistic regression model was used to analyze the relationship between unhealthy lifestyle score, smoking, alcohol consumption, other factors and hyperuricemia, and the stratified analysis was used to explore the modification effect of hypertension and other diseases on the relationship between unhealthy lifestyle and hyperuricemia. Results: A total of 11 748 participants were included in this study, the prevalence of hyperuricemia was 34.4%. Multivariate logistic regression model showed that current/previous smoking, current/previous alcohol consumption and BMI abnormality were risk factors for hyperuricemia, and the unhealthy lifestyle score showed a "cumulative" effect on the risk for hyperuricemia, with higher score increasing the risk of hyperuricemia, and the OR increased from 1.64 (95%CI: 1.34-2.00) to 2.89 (95%CI: 2.39-3.50). Stratified analysis showed that unhealthy lifestyles had a greater impact on the risk for hyperuricemia in people with hypertension and dyslipidemia. Conclusions: The coexistence of multiple unhealthy lifestyles might increase the risk of hyperuricemia, and this effect was stronger in participants with hypertension and dyslipidemia. Timely correction of unhealthy lifestyles, and control of hypertension and dyslipidemia might reduce the risk for hyperuricemia.

Exchange bias effect in polycrystalline Bi0.5Sr0.5Fe0.5Cr0.5O3 bulk

Bulk Bi_0.5Sr_0.5Fe_0.5Cr_0.5O₃ (BSFCO) is a new compound comprising the R3c structure. The structural, magnetic property and exchange bias (EB) details are investigated. The material was in the super-paramagnetic (SP) state at room temperature. Exchange bias usually occurs at the boundary between different magnetic states after field cooling (H_FC) acts on the sample. Here the result shows that changing H_FC from 1 to 6 T reduces the H_EB value by 16% at 2 K at the same time. Meanwhile, H_EB diminishes as the ferromagnetic layer thickness increases. The variation of (the thickness of ferromagnetic layer) t_FM with the change of H_FC leads to the tuning of H_EB by H_FC in BSFCO bulk. These effects are obviously different from the phenomenon seen in other oxide types.

[Establishment and preliminary clinical application of human intestinal fluid transplantation]

Objective: To explore and establish the preparation system of human intestinal fluid transplantation (HIFT) and HIFT capsule, and to preliminarily apply it to clinic. Methods: Strict standards for donor screening and management were established. The nasojejunal tube was catheterized into the distal jejunum, and then it was connected with an improved disposable sterile negative pressure collection device for the collection of human intestinal fluid. After that, it was prepared into capsules by filtering, adding 10% glycerin protectant and freeze-drying method. The amount of living bacteria was used as the standard of therapeutic dose. The living bacteria amount in fluid is ≥ 5.0×10⁸ /mL and the living bacteria proportion is ≥ 83%; the living bacteria amount in powder is ≥ 2.0×10⁶ /g and the living bacteria proportion is ≥ 81%; The observational indicators included: (1) the basic information of the donor, the amount of living bacteria in the HIF and powder. (2) Preliminary analysis of the treatment for ASD, which combined HIFT capsule with standard FMT capsule, from February to December 2021 (Clinical trial Registration Number: ChiCTR2100043929). Evaluation criteria: Trypan blue staining method was used to detect the living bacteria amount in fluid and powder. The Autism Behavior Checklist (ABC) and Childhood Autism Rating Scale (CARS) were used to evaluate the efficacy. Results: Compared with the parent donor, the standard donor was younger [(25.4±0.9) y vs. (30.7±3.2) y, t=-19.097, P=0.001] and had a lower body mass index [(19.7±0.5) kg/m² vs. (20.8±1.3) kg/m², t=-8.726, P=0.001], more in the living bacteria amount in powder [(7.47±1.52)×10⁶/g vs. (5.03±1.38)×10⁶/g, t=11.331, P=0.031], Chao index (205.4±6.8 vs. 194.2±7.2, t=10.415, P=0.001), and Shannon index (3.25±0.14 vs 2.72±0.27, t=19.465, P=0.001). The differences were statistically significant (all P<0.05). However, there were no significant differences in gender, drainage volume and total number of bacterial liquid colonies between the two groups (all P>0.05). Both the standard donor and the parent donor met the donor screening criteria, and the preparation fluid and powder met the treatment criteria. Eight patients received the treatment of HIFT combined with fecal microbiota transplantation (FMT). Preliminary statistical results showed that HIFT combined with FMT improved ABC and CARS at the 1st, 2nd, 3rd and 4th months. The differences were statistically significant (all P<0.05). No severe adverse reaction occurred. Conclusion: Based on the previous research on FMT preparation system and the clinical technology in our center, this study developed a high standard HIFT preparation system, and explored the clinical study of HIFT combined with FMT, in order to provide an innovative therapy for the treatment of diseases.

Photoluminescence and magnetism integrated multifunctional black phosphorus probes through controllable PO bond orbital hybridization

Biological probes with integrated photoluminescence and magnetism characteristics play a critical role in modern clinical diagnosis and surgical protocols combining fluorescence optical imaging (FOI) with magnetic resonance imaging (MRI) technology. However, traditional magnetic semiconductors can easily generate a spin splitting at the Fermi level and half-metallic electronic occupation, which will sharply reduce the radiation recombination efficiency of photogenerated carriers. To overcome this intrinsic contradiction, we propose a controllable oxidation strategy to introduce some particular PO bonds into black phosphorus nanosheets, in which the p orbital hybridization between P and O atoms not only provides some carrier recombination centers but also leads to a room-temperature spin polarization. As a result, the coexistence of photoluminescence and magnetism is realized in multifunctional black phosphorus probes with excellent biocompatibility. This work provides a new insight into integrating photoluminescence and magnetism together by intriguing atomic orbital hybridization.

Tuning Dzyaloshinskii-Moriya interaction via an electric field at the Co/h-BN interface

The Dzyaloshinsky-Moriya interaction (DMI) at the Co/h-BN interface can emerge and be enhanced by applying a downward electric field. The height of the Co atom relative to the h-BN layer with the electric field determines the variation of DMI. One half reduction of J₁ is beneficial to generate skyrmions. Tuning the DMI by an electric field sheds new light for research on skyrmions.

Metabolomics Changes of Serum and Tissues in Mice Died of Acute Tetracaine Poisoning

Abstract

Objective To study the changes of metabolites in serum and tissues （kidney, liver and heart） of mice died of acute tetracaine poisoning by metabolomics, to search for potential biomarkers and related metabolic pathways, and to provide new ideas for the identification of cause of death and research on toxicological mechanism of acute tetracaine poisoning. Methods Forty ICR mice were randomly divided into control group and acute tetracaine poisoning death group. The model of death from acute poisoning was established by intraperitoneal injection of tetracaine, and the metabolic profile of serum and tissues of mice was obtained by ultra-high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry （UPLC-Orbitrap HRMS）. Multivariate statistical principal component analysis （PCA） and orthogonal partial least square-discriminant analysis （OPLS-DA） were used, combined with t-test and fold change to identify the differential metabolites associated with death from acute tetracaine poisoning. Results Compared with the control group, the metabolic profiles of serum and tissues in the mice from acute tetracaine poisoning death group were significantly different. Eleven differential metabolites were identified in serum, including xanthine, spermine, 3-hydroxybutylamine, etc.; twenty-five differential metabolites were identified in liver, including adenylate, adenosine, citric acid, etc.; twelve differential metabolites were identified in heart, including hypoxanthine, guanine, guanosine, etc; four differential metabolites were identified in kidney, including taurochenodeoxycholic acid, 11, 12-epoxyeicosatrienoic acid, dimethylethanolamine and indole. Acute tetracaine poisoning mainly affected purine metabolism, tricarboxylic acid cycle, as well as metabolism of alanine, aspartic acid and glutamic acid. Conclusion The differential metabolites in serum and tissues of mice died of acute tetracaine poisoning are expected to be candidate biomarkers for this cause of death. The results can provide research basis for the mechanism and identification of acute tetracaine poisoning.

[Influence of Halogenated Hydroxyl-Alkanes Inhalation Anesthetic on the Determination of Ethanol Content in Blood]

Objective To study the influence of halogenated hydroxyl-alkanes inhalation anesthetic on the determination of ethanol content in blood. Methods Halogenated hydroxyl-alkanes were analyzed by headspace gas chromatography with double column confirmatory detection method. The influence of halogenated hydroxyl-alkanes on determination of ethanol content in blood sample by headspace gas chromatography was explored under the different detection conditions of KB-BAC1/ KB-BAC2 and J&W DB-ALC1/DB-ALC2 gas chromatographic column. Results The retention time of sevoflurane and enflurane was similar to that of ethanol and tert butanol respectively when using the J&W DB-ALC1/DB-ALC2 gas chromatographic column, and interfered with the detection of ethanol content in blood; only J&W DB-ALC1 gas chromatographic column can separate the sevoflurane and ethanol components, so as to eliminate their influence on the detection of ethanol content in blood. When using KB-BAC1/KB-BAC2 gas chromatographic column, the retention time of sevoflurane, isoflurane and ethanol is similar, especially that of sevoflurane and ethanol, and sevoflurane obviously interferes with the determination of ethanol content in blood. Conclusion Halogenated hydroxy-alkanes interfere with determination of ethanol content in blood by headspace gas chromatography. The interference can be discriminated effectively by choosing the suitable chromatographic column and double column confirmatory detection.

[Effects of fecal microbiota transplantation in different routes on the clinical efficacy of slow transit constipation]

Objective: To evaluate the efficacy and safety of the fecal microbiota transplantation (FMT) in the different route administration for slow transit constipation (STC). Methods: A retrospective cohort study was conducted. The clinical data of 270 STC patients who voluntarily received FMT treatment in the Tenth People's Hospital of Tongji University from May 2018 to May 2019 were collected. Non-relative healthy adult standard donors were applied. The treatment routes of bacterial flora transplantation included nasojejunal tube (nasal enteral tube group, 120 cases), oral enterobacterial capsule treatment (oral capsule group, 120 cases), and colonoscopy infusion (colonoscopy group, 30 cases). The efficacy and safety of treatment among the three groups were compared. Results: Transplanted bacteria of three groups were extracted from 100 g of fresh feces. All the patients successfully completed the transplantation. The waiting time for the nasal enteral tube group, oral capsule group and colonoscopy group was (1.5±0.5) d, (0.4±0.3) d and (3.6±0.8) d respectively; the cost of establishing the transplantation path was (495±20) yuan, (25±10) yuan and (1420±45) yuan respectively, whose differences were statistically significant (F=9.210, P=0.03; F=10.600,P=0.01). The clinical improvement rates at 1 month after FMT treatment in the nasojejunal tube group, oral capsule group and colonoscopy group were 74.2% (89/120), 60.0% (72/120) and 53.3% (16/30) respectively, whose difference was statistically significant (χ(2)=5.990, P<0.05). The clinical improvement rates at 3 months after treatment were 71.1% (69/97), 53.6% (45/84), and 44.0% (11/25) respectively, whose difference was statistically significant (χ(2)=7.620, P<0.05). The incidence of adverse reactions in the colonoscopy group was 76.7% (23/30), which was higher than that in the nasal nasojejunal group (39.2%, 47/120) and oral capsule group (21.7%, 26/120). The most common adverse reactions in the nasojejunal tube group, oral capsule group and colonoscopy group were respiratory discomfort (17.5%, 21/120), nausea and vomiting (10.0%, 12/120), and diarrhea (36.7%, 11/30). During the 3-month follow-up after treatment, no FMT-related adverse reactions were reported. Conclusions: The nasojejunal tube route has stable clinical efficacy and operability, while the oral capsule route has shorter waiting time and less cost. However, the adverse reactions caused by different transplantation methods are different, thus personalized transplantation method should be recommended.

[Efficacy analysis of fecal microbiota transplantation in the treatment of 2010 patients with intestinal disorders]

Objective: To evaluate the efficacy and safety of fecal microbiota transplantation (FMT) for intestinal disorders. Methods: A retrospectively descriptive cohort study was carried out. Clinical data of 2010 patients who underwent FMT and received follow-up for more than 3 months from May 2014 to November 2018 were collected, including 1,206 cases from Tongji University Shanghai Tenth People's Hospital and 804 cases from Nanjing Eastern Military General Hospital. Of the 2,010 patients, 797 were male and 1,213 were female, with a mean age of (49.4±16.5) years old. Inclusion criteria were those with indications for FMT and voluntary treatment of FMT. Pregnant or lactating women, patients with end-stage disease, cases who were participating or participated in other clinical trials within 3 months, and patients with previous bowel history of pathogen infection, oral antibiotics or proton pump inhibitors (PPI) for the recent2 weeks, and those at immunosuppressive state were excluded. Informed consent was obtained from the enrolled patients and their families. There were 1,356 cases of constipation, 175 cases of inflammatory bowel disease, 148 cases of chronic diarrhea, 127 cases of radiation enteritis, 119 cases of irritable bowel syndrome, and 85 cases of autism (complicating with intestinal disorders). FMT donor requirements: (1) 18 to 30 years old non-relatives, non-pregnant healthy adults with healthy lifestyle and good eating habits as volunteers to participate in fecal donation; (2) no administration of antibiotics within 3 months; (3) no chronic diseases such as constipation, irritable bowel syndrome, inflammatory bowel disease, etc., no autoimmune disease, not in immunosuppressive state, no history of malignant disease; (4) negative pathogen examination of infectious diseases (hepatitis B virus, hepatitis C virus, syphilis, HIV, etc.); (5) negative fecal examination (C.difficile, dysentery bacillus, Shigella, Campylobacter, parasites, etc.). The donor requirements after enrollment: (1) physical examination was reviewed once every two months, and the result still met the above requirements; (2) 16S rRNA sequencing was performed for every fecal donation in order to ensure that the composition and diversity of the fecal flora was stable and reliable. The preparation of the stool suspension referred to the Amsterdam criteria and the preparation process was less than 1 hour. The preparation of the FMT capsule was processed by pre-freezing the stool suspension after the preparation of the above suspension, and the frozen sample was transferred into a freeze dryer for freezing. The dried and lyophilized powder was encapsulated in capsules, and the capsule shell was made of acid-resistant hypromellose capsule (No.0) and pediatric-specific capsule (No.3), sealed and packaged in a-20℃ refrigerator. Three ways of accepting FMT treatment pathways included 6-day transplantation after the placement of the nasointestinal tube, 6-day oral FMT capsule transplantation and one-time transplantation through colonoscopy. Intestinal preparation (nasointestinal tube feeding of polyethylene glycol until watery stool) was carried out before transplantation. Other treatments were stopped during treatment and follow-up, and any medication was not recommended when necessary. Results: Of the 2010 patients, 1,497 cases received nasointestinal tube transplantation (nasointestinal tube group), 452 cases oral capsule transplantation (oral capsule group) and 61 cases colonoscopy (colonoscopy group). At 3 time points of 3, 12, and 36 months after FMT, the clinical cure rates and the clinical improvement rates were 41.3% (560/1 356), 35.2% (320/909), 31.4% (69/220), and 29.0% (393/1 356), 27.8% (253/909), 29.1% (64/220), respectively in constipation patients; 33.1% (58/175), 29.9% (35/117), 24.5% (12/49), and 31.4% (55/175), 27.4% (32/117), 57.1% (28/49), respectively in inflammatory bowel disease patients; 87.8% (130/148), 81.8% (81/99), 78.3% (36/46), and 8.1% (12/148), 7.1% (7/99), 4.3% (2/46), respectively in chronic diarrhea patients; 61.4% (78/127), 56.5% (48/85), 47.6% (20/42), and 21.2% (27/127), 15.3% (13/85), 14.3% (6/42), respectively in radiation enteritis patients; 53.8% (64/119), 45.0% (36/80), 6/15, and 21.0% (25/119), 26.2% (21/80), 4/15, respectively in irritable bowel syndrome patients; 23.5% (20/85), 22.8% (13/57), 20.0%(5/25), and 55.3% (47/85), 49.1% (28/57), 40.0% (10/25), respectively in autism patients. Meanwhile the clinical cure rates and the clinical improvement rates at 3, 12, and 36 months were 47.7% (714/1 497), 42.8% (425/994), 39.1% (128/327), and 29.1% (436/1 497), 27.0% (268/994), 28.1% (92/327), respectively in the nasointestinal tube group; 38.7% (175/452), 30.2% (91/301), 33.3% (16/48), and 24.3% (110/452), 26.2% (79/301), 25.0% (12/48), respectively in the oral capsule group; 34.4% (21/61), 32.7% (17/52), 18.2% (4/22), and 21.3% (13/61), 13.5% (7/52), 45.5% (10/22), respectively in colonoscopy group. No serious adverse events occurred during treatment and follow-up period. The adverse event of nasointestinal tube group presented higher ratio of discomfort in respiratorytract accounting for 13.1% (196/1497); the oral capsule group had a higher proportion of nausea and vomiting when swallowing capsules accounting for 7.1% (32/452); the colonoscopy group was mainly diarrhea, accounting for 37.7% (23/61). The above symptoms disappeared after the nasointestinal tube was removed, or after treatment ended, or within 1 to 3 days after hospitalization. Conclusion: FMT is a safe and effective method for the treatment of intestinal dysfunction.

[Three-dimensional finite element analysis of cantilever fixed bridge supported by implants with mandibular central incisor]

Objective: To investigate effect of the contact surface between the bridge and the adjacent teeth on the stress distribution of the implant and bone tissue and the displacement of the prosthesis in the cantilever fixed implant bridge restoring missing mandibular central incisors. Methods: Two-dimensional images of the mandible and dentition in healthy adults were obtained using CT data. A three-dimensional finite element model of cantilever fixed bridge supported by implants with mandibular central incisor was established by computer reconstruction technique.The contact surface between the bridge and the adjacent natural tooth was designed as "oval" and "trapezoid". The "trapezoid" has a slightly smaller median diameter on the labial side and a slightly larger medial diameter on the lingual side. Loading of 120 N was applied on the tangential margin of the middle line of the long axis of the bridge 41. The direction was set at 0°, which was parallel to the long axis of the tooth and downward. The buccal to lingual and downward angles were 30°, 45° and 60°, respectively, perpendicular to the long axis of the tooth and 90° to the lingual side.The stress distribution of the implant and surrounding bone tissue and the displacement of the prosthesis were compared between the two models. Results: Under axial and buccolingual loading, the maximum equivalent stress peak in the implant and surrounding bone tissue in the cantilever with trapezoidal contact surface design and the maximum displacement of the prosthesis were lower. Moreover, the distribution of stress was more balanced and the concentration range of stress was smaller. With the loading angle increasing, this trend was more obvious. When loading angle increased to 90°, the maximum equivalent stress and the maximum displacement of the elliptic contact surface model implant and surrounding bone tissue were 196 and 101 MPa and 0.196 mm, respectively, while the trapezoidal contact surface model were 157 and 72 MPa and 0.164 mm, respectively. Conclusions: The trapezoidal contact surface of the bridge and the adjacent teeth in the cantilever fixed bridge supported by implants with mandibular central incisor is beneficial to reduce the impact of the leverage on the implant and surrounding bone tissue.

Analysis of Common Herbicides in Blood by UPLC-HRMS

OBJECTIVES

To develop a method to screen and quantify 10 common herbicides （paraquat, diquat, glyphosate, glufosinate, cyanazine, atrazine, metazachlor, acetochlor, chlorsulfuron, and metsulfuron） in blood.

METHODS

With acetonitrile-water solution [V（acetonitrile）∶V（water）=3∶1] as protein precipitant, 10 common herbicides in blood were detected using ultra-high performance liquid chromatography-high resolution mass spectrometry （UPLC-HRMS）.

RESULTS

All the 10 herbicides had good linearity in their linear range （coefficient of determination R²≥0.993）, with the recovery rates 67.4%-111.9%, the relative standard deviations 1.5%-10.8%, the accuracies 85.1%-106.1%, intra-day precisions 2.7%-13.5%, and inter-day precisions 3.3%-13.3%.

CONCLUSIONS

This method is easy to operate with high recovery rates. It enables rapid and accurate qualitative screening and quantitative analysis of various herbicides in blood simultaneously.

Observation of a charged charmoniumlike structure in e+ e- → π+ π- J/ψ at sqrt[s] = 4.26 GeV

We study the process ee+ e- → π+ π- J/ψ at a center-of-mass energy of 4.260 GeV using a 525  pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross section is measured to be (62.9±1.9±3.7)  pb, consistent with the production of the Y(4260). We observe a structure at around 3.9  GeV/c2 in the π(±)J/ψ mass spectrum, which we refer to as the Z(c)(3900). If interpreted as a new particle, it is unusual in that it carries an electric charge and couples to charmonium. A fit to the π(±)J/ψ invariant mass spectrum, neglecting interference, results in a mass of (3899.0±3.6±4.9)  MeV/c2 and a width of (46±10±20)  MeV. Its production ratio is measured to be R = (σ(e+ e- → π(±)Z(c)(3900)(∓) → π+ π- J/ψ)/σ(e+ e- → π+ π- J/ψ)) = (21.5±3.3±7.5)%. In all measurements the first errors are statistical and the second are systematic.

Observation of two new N* resonances in the decay ψ(3686)→ppπ0

Based on 106×10(6)ψ(3686) events collected with the BESIII detector at the BEPCII facility, a partial wave analysis of ψ(3686)→ppπ0 is performed. The branching fraction of this channel has been determined to be B(ψ(3686)→ppπ0)=(1.65±0.03±0.15)×10(-4). In this decay, 7 N* intermediate resonances are observed. Among these, two new resonances, N(2300) and N(2570) are significant, one 1/2+ resonance with a mass of 2300(-30-0)(+40+109)  MeV/c2 and width of 340(-30-58)(+30+110)  MeV/c2, and one 5/2- resonance with a mass of 2570(-10-10)(+19+34)  MeV/c2 and width of 250(-24-21)(+14+69)  MeV/c2. For the remaining 5 N* intermediate resonances [N(1440), N(1520), N(1535), N(1650) and N(1720)], the analysis yields mass and width values that are consistent with those from established resonances.

Evidence for the direct two-photon transition from ψ(3686) to J/ψ

The two-photon transition ψ(3686)→γγJ/ψ is studied in a sample of 1.06×10(8) ψ(3686) decays collected by the BESIII detector. The branching fraction is measured to be (3.1±0.6(stat)(-1.0)(+0.8)(syst))×10(-4) using J/ψ→e(+)e(-) and J/ψ→μ(+)μ(-) decays, and its upper limit is estimated to be 4.5×10(-4) at the 90% confidence level. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the ψ(3686) decay plane and the J/ψ polarization in this decay are also studied. In addition, the product branching fractions of sequential E1 transitions ψ(3686)→γχ(cJ) and χ(cJ)→γJ/ψ(J=0,1,2) are reported.

First observation of the M1 transition ψ(3686)→γη(c)(2S)

Using a sample of 106×10(6) ψ(3686) events collected with the BESIII detector at the BEPCII storage ring, we have made the first measurement of the M1 transition between the radially excited charmonium S-wave spin-triplet and the radially excited S-wave spin-singlet states: ψ(3686)→γη(c)(2S). Analyses of the processes ψ(3686)→γη(c)(2S) with η(c)(2S)→K(S)(0)K(±)π(∓) and K(+)K(-)π(0) give an η(c)(2S) signal with a statistical significance of greater than 10 standard deviations under a wide range of assumptions about the signal and background properties. The data are used to obtain measurements of the η(c)(2S) mass (M(η(c)(2S))=3637.6±2.9(stat)±1.6(syst) MeV/c(2)), width (Γ(η(c)(2S))=16.9±6.4(stat)±4.8(syst) MeV), and the product branching-fraction (B(ψ(3686)→γη(c)(2S))×B(η(c)(2S)→KKπ)=(1.30±0.20(stat)±0.30(syst))×10(-5)). Combining our result with a BABAR measurement of B(η(c)(2S)→KKπ), we find the branching fraction of the M1 transition to be B(ψ(3686)→γη(c)(2S))=(6.8±1.1(stat)±4.5(syst))×10(-4).

Measurements of the mass and width of the η(c) using the decay ψ(3686)→γη(c)

The mass and width of the lowest-lying S-wave spin singlet charmonium state, the η(c), are measured using a data sample of 1.06×10(8) ψ(3686) decays collected with the BESIII detector at the BEPCII storage ring. We use a model that incorporates full interference between the signal reaction, ψ(3686)→γη(c), and a nonresonant radiative background to describe the line shape of the η(c) successfully. We measure the η(c) mass to be 2984.3±0.6±0.6 MeV/c(2) and the total width to be 32.0±1.2±1.0 MeV, where the first errors are statistical and the second are systematic.

First observation of η(1405) decays into f(0)(980)π0

The decays J/ψ → γ π+ π- π0 and J/ψ → γ π0 π0 π0 are analyzed using a sample of 225×10(6) J/ψ events collected with the BESIII detector. The decay of η(1405) → f(0)(980)π0 with a large isospin violation is observed for the first time. The width of the f(0)(980) observed in the dipion mass spectra is anomalously narrower than the world average. Decay rates for three-pion decays of the η' are also measured precisely.

Spin-parity analysis of pp¯ mass threshold structure in J/ψ and ψ(3686) radiative decays

A partial wave analysis of the pp¯ mass-threshold enhancement in the reaction J/ψ→γpp¯ is used to determine its J(PC) quantum numbers to be 0(-+), its peak mass to be below threshold at M=1832(-5)(+19)(stat)(-17)(+18)(syst)±19(model) MeV/c(2), and its total width to be Γ<76 MeV/c(2) at the 90% C.L. The product of branching ratios is measured to be BR[J/ψ→γX(pp¯)]BR[X(pp¯)→pp¯]=[9.0(-1.1)(+0.4)(stat)(-5.0)(+1.5)(syst)±2.3(model)]×10(-5). A similar analysis performed on ψ(3686)→γpp¯ decays shows, for the first time, the presence of a corresponding enhancement with a production rate relative to that for J/ψ decays of R=[5.08(-0.45)(+0.71)(stat)(-3.58)(+0.67)(syst)±0.12(model)]%.

ηπ+ π- resonant structure around 1.8 GeV/c(2) and η(1405) in J/ψ → ωηπ+ π-

We present results of a study of the decay J/ψ → ωηπ+ π- using a sample of (225.2 ± 2.8) × 10(6) J/ψ events collected by the BESIII detector, and report the observation of a new process J/ψ → ωX(1870) with a statistical significance of 7.2σ, in which X(1870) decays to a(0)(±)(980)π±. Fitting to ηπ+ π- mass spectrum yields a mass M = 1877.3 ± 6.3(stat)(-7.4)(+3.4)(syst) MeV/c(2), a width Γ = 57 ± 12(stat)(-4)(+19)(syst) MeV/c(2), and a product branching fraction B(J/ψ → ωX) × B(X→a(0)(±)(980)π±) × B(a(0) (±)(980) → ηπ±) = [1.50 ± 0.26(stat)(-0.36)(+0.72) (syst)] × 10(-4). Signals for J/ψ → ωf(1)(1285) and J/ψ → ω η(1405) are also clearly observed and measured.

Observation of χ(c1) decays into vector meson pairs φφ, ωω, and ωφ

Using (106±4)×10⁻⁶ ψ(3686) events accumulated with the BESIII detector at the BEPCII e⁺e⁻ collider, we present the first measurement of decays of χ(c1) to vector meson pairs φφ, ωω, and ωφ. The branching fractions are measured to be (4.4±0.3±0.5)×10⁻⁴, (6.0±0.3±0.7)×10⁻⁴, and (2.2±0.6±0.2)×10⁻⁵, for χ(c1)→φφ, ωω, and ωφ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χ(cJ) decays. In addition, the measurement of χ(cJ)→ωφ provides the first indication of the rate of doubly OZI-suppressed χ(cJ) decay. Finally, we present improved measurements for the branching fractions of χ(c0) and χ(c2) to vector meson pairs.

Isolation and characterization of eight polymorphic microsatellite loci for the coconut pest, Brontispa longissima (Coleoptera: Hispidae)

Brontispa longissima is one of the most serious insect pests of coconut in Southeast Asia; it was first discovered on Hainan Island in June 2002. Despite the economic risk associated with this pest, genetic aspects of the invasion process have remained relatively unexplored. Using microsatellite markers, we investigated the population structure, genetic variability and pattern of invasion in various geographic populations. The methodology was based on a modified biotin-capture method. Eight polymorphic microsatellite loci were isolated and characterized for the pest. The allele number per locus varied from 2 to 3 (N = 30). The expected and observed heterozygosities of the eight loci ranged from 0.042 to 0.509 and from 0.042 to 0.963, respectively. Although the frequency of polymorphisms was not very high in this population, the microsatellite loci that were isolated will be useful for investigating the genetic diversity and migration routes of B. longissima populations.

Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/ψ→γπ+π-η'

With a sample of (225.2±2.8)×10(6) J/ψ events registered in the BESIII detector, J/ψ→γπ(+)π(-)η(') is studied using two η(') decay modes: η(')→π(+)π(-)η and η(')→γρ(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the π(+)π(-)η(') invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.4σ, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.

Evidence for ψ' decays into γπ0 and γη

The decays ψ'→γπ(0), γη and γη' are studied using data collected with the BESIII detector at the BEPCII e(+)e(-) collider. The processes ψ'→γπ(0) and ψ'→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ'→γπ(0))=(1.58±0.40±0.13)×10(-6), B(ψ'→γη)=(1.38±0.48±0.09)×10(-6), and B(ψ'→γη')=(126±3±8)×10(-6), where the first errors are statistical and the second ones systematic.

Measurements of h(c)(1P(1)) in psi' decays

We present measurements of the charmonium state h(c)(1P(1)) made with 106x10(6) psi' events collected by BESIII at BEPCII. Clear signals are observed for psi'-->pi0 h(c) with and without the subsequent radiative decay h(c)-->gamma eta(c). First measurements of the absolute branching ratios B(psi'-->pi0 h(c)) = (8.4+/-1.3+/-1.0) x 10(-4) and B(h(c)-->gamma eta(c)) = (54.3+/-6.7+/-5.2)% are presented. A statistics-limited determination of the previously unmeasured h(c) width leads to an upper limit Gamma(h(c))<1.44 MeV (90% confidence). Measurements of M(h(c)) = 3525.40+/-0.13+/-0.18 MeV/c2 and B(psi'-->pi0 h(c)) x B(h(c)-->gamma eta(c)) = (4.58+/-0.40+/-0.50) x 10(-4) are consistent with previous results.

[Cloning and sequence analysis of RESA gene fragment of Plasmodium falciparum isolate FCC1/HN]

OBJECTIVE

To determine the nucleotide sequence of the 3'-termal of the RESA gene Plasmodium falciparum isolate FCC1/HN, and find out the differences of the sequences of RESA gene among isolate FCC1/HN, FC27, NF7 and Palo Alto.

METHODS

3'-terminal fragment of RESA gene of P. falciparum isolate FCC1/HN was amplified by PCR method, then was cloned into pMD18-T vector. The recombinant was screened and identified by BamHI + XhoI and PCR technique. The nucleotide sequence of the 3'-terminal of the RESA gene was determined by the dideoxy chain termination method. DNASTAR and BLAST software were used to compare and analyze the RESA gene sequences among the different isolates.

RESULTS

The 3'-termal fragment of the RESA gene with about 846 bp was specifically amplified by PCR, the recombinant pMD18-T-RESA was successfully constructed. Different degrees of diversity of the RESA gene sequences were found among P. falciparum isolates FCC1/HN, FC27, NF7 and Palo Alto.

CONCLUSION

There were differences in the sequences of RESA gene among the P. falciparum isolate FCC1/HN and three other isolates (FC27, NF7 and Palto alto).

Presynaptic modulation of GABAergic inhibition by GABA(B) receptors in the rat's inferior colliculus

Whole-cell patch clamp recordings were made from neurons in a brain slice preparation of the inferior colliculus in 11-15-day-old rat pups. Synaptic responses were elicited by applying a current pulse to the lateral lemniscus just below the central nucleus of the inferior colliculus. To examine GABAergic inhibition in the inferior colliculus all excitatory postsynaptic potentials and glycinergic inhibitory postsynaptic potentials were blocked by bath application of their respective antagonists and the contribution of GABA(B) receptors was determined for the remaining inhibitory postsynaptic potentials. For most cells the isolated inhibitory postsynaptic potential was completely blocked by the GABA(A) receptor antagonist, bicuculline, but was unaffected by the GABA(B) receptor antagonist, phaclofen. The GABA(B) receptor agonist, baclofen (10-20 microM), decreased the amplitude of the inhibitory postsynaptic potentials. This effect was completely blocked by phaclofen. Baclofen did not increase the cell membrane conductance or alter the rate of firing produced by depolarization of the cell membrane. In contrast, muscimol, a GABA(A) receptor agonist, greatly increased membrane conductance and lowered the firing rate produced by depolarization. Our results indicate that GABAergic inhibition in the auditory midbrain can be reduced by the activation of GABA(B) receptors and suggest that the effects are presynaptic.

Genetic selection in Saccharomyces of mutant mammalian adenylyl cyclases with elevated basal activities

We show that co-expression of rat Galphas together with type I, II, IV, or VI mammalian adenylyl cyclase (AC) can suppress the growth defect of cyr1 strains of Saccharomyces cerevisiae, which lack a functional endogenous AC. Complemention of cvr1 is not observed in the absence of Galphas, indicating that the mammalian ACs retain their normal regulatory behavior in yeast. Selection for Galphas-independent growth of (cyr1 strains expressing type IV AC yielded several ACIV mutants with enhanced basal activity, each of which had a single amino acid substitution in the conserved C1a or C2a region of the protein. Expression of two of the mutant ACs in HEK293 cells resulted in increased levels of cAMP and elevated adenylyl cyclase activity. Further selection for reverting mutations in one of these constitutively active AC mutants yielded three independent intragenic suppressor mutations. The distribution of the activating and suppressor mutations throughout both C1a and C2a is consistent with a model in which the enhanced basal activity results from an increase in the affinity between C1a and C2a. These results demonstrate the utility of Saccharomyces as a tool for the identification of informative mutant forms of mammalian ACs.

Expressed sequence tags from a NaCl-treated Suaeda salsa cDNA library

Past efforts to improve plant tolerance to osmotic stress have had limited success owing to the genetic complexity of stress responses. The first step towards cataloging and categorizing genetically complex abotic stress responses is the rapid discovery of genes by the large-scale partial sequencing of randomly selected cDNA clones or expressed sequence tags (ESTs). Suaeda salsa, which can survive seawater-level salinity, is a favorite halophytic model for salt tolerant research. We constructed a NaCl-treated cDNA library of Suaeda salsa and sequenced 1048 randomly selected clones, out of which 1016 clones produced readable sequences (773 showed homology to previously identified genes, 227 matched unknown protein coding regions, 16 anomalous sequences or sequences of bacterial origin were excluded from further analysis). By sequence analysis we identified 492 unique clones: 315 showed homology to previously identified genes, 177 matched unknown protein coding regions (101 of which have been found before in other organisms and 76 are completely novel). All our EST data are available on the Internet. We believe that our dbEST and the associated DNA materials will be a useful source to scientists engaging in stress-tolerance study.

GDNF protects the cochlea against noise damage

Glial-derived neurotrophic factor (GDNF) was tested for its ability to prevent hearing and sensory cell loss in guinea pigs exposed to acoustic trauma. Hearing was measured prior to any treatment. Animals were exposed to damaging levels of noise either before or after local application of GDNF to one ear. Four weeks later, hearing and sensory cell loss was greater in the control ear than in the ear receiving GDNF before acoustic trauma or 2 h after trauma, but not 4 or 6 h after trauma. The results indicate that GDNF treatment in vivo can prevent cochlear sensory cell damage and hearing loss if present during or shortly after acoustic trauma.

Cutaneous infection by Scedosporium apiospermum and its successful treatment with itraconazole

We report the case of a 42-year-old man with a 13-year history of bilateral faciocervical infiltrative erythema, which had been misdiagnosed as tuberculoderma and which had failed to respond to treatment with adrenal corticosteroids and antituberculotics. On admission to the department, Scedosporium apiospermum was identified on lesion biopsies and fungus cultures as the causative agent and a diagnosis of cutaneous infection by S. apiospermum was made. This is the first report of chronic skin granuloma caused by S. apiospermum in China. Treatment with oral itraconazole (100-400 mg/day) led to clinical cure within 4 months.

The laryngeal mask airway--clinical experience

The laryngeal mask airway (LMA), a new type of airway, when it is inserted blindly into the hypopharynx forms a seal around the larynx and allows easy and convenient spontaneous or controlled positive pressure ventilation. A clinical application of the LMA to 70 surgical patients in our hospital have been evaluated. LMA was successfully applied to 68 (97%) patients who all received general anesthesia with unobstructed controlled ventilation. The patency of the airway did not change throughout the course of anesthesia. There were 2 patients whose airway was obstructed at the first attempt due to downfolding of epiglottis; in one of them the obstruction was confirmed by flexible fibreoptic laryngoscopy. Subsequent placement was successful in these 2 patients. Insertion failure was seen in 2 patients respectively due to small mouth and excessive salivation. The placement of LMA does not require laryngoscopy and there is no fear of misplacement in the esophagus. It becomes obvious that the LMA would substantially gain a place in the armamentarium in anesthesia and we think that its use would be of interest to anesthesiologists.

A fluorescent analogue of hydrin 1: a new probe for vasotocin receptors

Hydrin 1 is the biosynthetic precursor of vasotocin in Xenopus laevis. We have synthesized deamino and fluorescein analogues of hydrin 1 and characterized their physiological action in the urinary bladder of the toad, Bufo marinus. 1-Deamino-hydrin 1 (d-hydrin) was more potent than vasotocin in stimulating osmotic water flow across intact bladders and more potent than vasotocin in displacing tritium-labeled vasopressin [( 3H]AVP) from cell membranes. 1-Deamino-[11-lysine (fluorescein)]-hydrin 1 (flu-hydrin) was found to be the most potent fluorescent vasotocin receptor probe synthesized to date. Flu-hydrin increased osmotic water flow across bladders with a half-maximal effective dose (ED50) value of 6 x 10(-10) M and displaced [3H]AVP from membranes with a half-maximal concentration (IC50) value of 3 x 10(-9) M. The hydrosmotic response to flu-hydrin was blocked by 1-deamino-[4-lysine (p-azido-benzoyl)]arginine vasotocin [d4Lys(N3)-AVT]. Epifluorescence light microscopic studies showed vesicular uptake of flu-hydrin at the basolateral membrane of toad bladder epithelial cells, and this uptake was blocked by d4Lys(N3)AVT. This study shows that d-hydrin can serve as a foundation molecule to which reporter groups, such as fluorescent residues, can be attached with better preservation of hydrosmotic activity than is possible with similar modifications of vasotocin.

[cis-diamminedichloroplatinum cochlear toxicity]

Twenty-nine guinea pigs were divided into three groups. The first group received distilled water 2 ml/kg ip daily; the second group received DDP 2 mg/kg ip daily; and the third group DDP 4 mg/kg ip daily. ABR hearing threshold was tested before injection. Twenty-four hours after systemic administration, ABR hearing threshold was tested again. The animals were killed and the cochlear specimens were observed under light, scanning and transmission electron microscopes. No abnormality regarding ABR hearing threshold and cochlear morphology was observed in the first group. In the second group, ABR hearing threshold was elevated, inner and outer hair cells, supporting cells, striae vascularis and spiral ganglions were damaged. In the third group, ABR hearing threshold elevated markedly. All above-mentioned cells were severely damaged. The experiment showed that the cochlear damage induced by DDP was dose related. The severest damage was seen in the second turn of the cochlea. The damage to the Deiters' cells was earliest and severest. The outer hair cells were more vulnerable to the damage than the inner hair cells did.

Synthesis and biological activities of a photoaffinity probe for vasotocin receptors

This study reports the synthesis and biological activities of 1-desamino, 7-lysine-(4-azidobenzoyl), 8-arginine vasotocin (d7-N3-AVT). This compound was found to be biologically active in the rat antidiuretic assay (20 U/mg), to behave as an antagonist of vasopressin in the rat pressor assay (pA2 = 6.6), and to yield a half-maximal hydroosmotic response in the isolated toad urinary bladder at a bath concentration of 2.4 X 10(-8) M. When toad bladders were exposed to d7-N3-AVT in the presence of long wavelength UV light, the hydroosmotic response persisted in spite of prolonged and repeated periods of washout. By contrast, the hydroosmotic response in control bladders after stimulation with d7-N3-AVT in the absence of UV irradiation was fully reversed within 15 min of washout. A membrane preparation derived from bladders that had been photolabeled with d7-N3-AVT and washed for 1 h specifically bound 325 fmol [3H]vasopressin/mg protein. Matched bladders exposed to the analog in the absence of UV irradiation and washed for 1 h specifically bound 591 fmol [3H]vasopressin per mg of protein. These studies indicate that d7-N3-AVT binds covalently to hydroosmotic receptors of toad urinary bladder and forms a complex that is functional in triggering an increase in the permeability to water of the epithelium. This analog may prove useful in the isolation and purification of vasotocin receptors in lower vertebrates.

Covalent labeling of hydrosmotic toad bladder receptors with an antagonist of vasotocin

A photoreactive analogue of vasotocin, [1-desamino,4-lysine(azidobenzoyl),8-arginine]vasotocin (4-N3-AVT), has been examined in the isolated toad urinary bladder for biological activity and binding to hormonal receptors. Although 4-N3-AVT induced only a small increase in bladder permeability to water, it behaved as a potent inhibitor of hydrosmotic action of [8-arginine]vasotocin (AVT) and [8-arginine]vasopressin (AVP). The inhibitory action of 4-N3-AVT was readily reversed on removal of the analogue from the serosal bathing solution. On the other hand, when bladders were exposed to 4-N3-AVT in the presence of long wavelength UV light (365 nm), the inhibition by 4-N3-AVT was not reversed on washout of the analogue. The dose of vasopressin required for a half-maximal response (ED50 value) was increased from 5 X 10(-9) to 1.3 X 10(-7) M in bladders photolabeled with 4-N3-AVT and the maximal response capacity of the tissue (intrinsic activity) was reduced to 79% of nonphotolabeled controls. A crude membrane preparation derived from bladders photolabeled with 4-N3-AVT contained 72 fmol of specific binding sites for tritium-labeled vasopressin per milligram protein, whereas nonphotolabeled controls had 136 fmol of specific binding sites per milligram protein. These observations suggest that 4-N3-AVT forms a covalent bond with hydrosmotic receptors in the presence of UV light. This is the first antagonistic photoaffinity analogue observed in the toad bladder and it may serve as a useful tool for analyzing the cellular mechanism of action of antidiuretic hormone.

Vasopressin binding sites in toad bladder: studies with the photoaffinity analogue [Phe(p-N3)3]AVP

Toad bladders were exposed to [Phe(p-N3)3]AVP (N3-AVP), an analogue of vasopressin with a photoreactive p-azido group in position three, in the presence and absence of ultraviolet (UV) light. Bladders exposed to the analogue in the presence of UV light showed an increase in membrane permeability to water, which persisted in spite of repeated and prolonged washout of analogue. In contrast, the hydroosmotic response induced by the analogue in the absence of UV light was readily reversed on washout. Aliquots of a broken epithelial cell preparation, derived from bladders that had been exposed to the analogue in the presence of UV light, bound less tritium-labeled vasopressin ([3H]AVP) than control aliquots that had been exposed to the analogue in the absence of UV irradiation or irradiated in the absence of the analogue. Membrane preparations that had not been photolabeled had specific binding sites for [3H]AVP in excess of 1,800 fmol/mg protein without evidence of saturation at a [3H]AVP concentration of 250 nM. Conversely, photolabeled membranes were saturated at a [3H]AVP concentration of 100 nM. The present studies demonstrate that a high proportion of [3H]AVP binding sites can be covalently labeled with N3-AVP and that at least some of these N3-AVP-bound sites are functional in triggering an increase in membrane permeability to water.

Occurrence of donor Langerhans cells in mouse and rat chimeras and their replacement in skin grafts

Evidence is presented that some endogenous Langerhans cells (LCs) may persist indefinitely in skin grafts. This evidence is based on the observation that although 2 weeks after grafting F1 hybrid mice and rats with genetically compatible skin, most of the LCs in the grafts were replaced with those of the host, some LCs of graft origin persisted for as long as the grafts were followed (154 days in mice and 249 days in rats). It has also been demonstrated that the spleen may be as good a source of LCs as the marrow. Thus, 6 weeks after lethally irradiated mice were restored with F1 hybrid spleen cells, most of the LCs in the epidermis of their pinnae were of donor origin. LCs of donor origin also were found in the epidermis of the pinnae of animals that had been inoculated at birth with spleen and lymph node cells (mice) or bone marrow cells (rats). Hence the occurrence of these cells provides another means of confirming that tolerance (chimerism) has been induced.

Downregulation of vasopressin receptors in toad bladder

Binding of tritium-labeled vasopressin [( 3H]AVP) to a broken epithelial cell preparation of the toad's urinary bladder has been related to hormonal action on water and urea transport across the intact tissue. Hormone binding to receptor sites and permeability changes were initiated at the same concentration of hormone (0.4 nM). Half-maximal urea and water permeability responses were observed with 3.1 and 5.6 nM AVP, respectively, although half-maximal receptor saturation required considerably higher concentrations of hormone (less than 500 nM). Because maximal permeability responses were obtained with occupation of approximately 200 fmol/mg protein receptor sites and the total receptor density was in excess of 2,000 fmol/mg protein, there is apparently a receptor reserve in this tissue. The antidiuretic hormone employed by the toad is vasotocin (AVT). This compound was 60-fold more effective than AVP in displacing [3H]AVP from receptor sites. Preincubation of bladders with AVT resulted in downregulation of receptor sites. Although the magnitude of receptor loss was equivalent in the presence or absence of a transmembrane osmotic pressure gradient, the capacity of AVT to induce permeability changes was more markedly reduced in the presence of an osmotic gradient. This observation suggests that the negative-feedback signal initiated by water flow through the hormone target cell diminishes sensitivity to hormone by a mechanism other than by a reduction in the number of surface receptors or by a decrease in their affinity for the hormone.

Synthesis and biological activities of a fluorescent photoaffinity analog of vasopressin

The present study describes the synthesis and biological activities of a vasopressin (VP) analog which binds covalently to receptors via a photoreactive p-azido group in position 3 and which contains a rhodamine label in position 8 for localization of hormone-receptor complexes by image-intensified fluorescence microscopy. 1-Deamino[3-(p-azidophenylalanine)]-N epsilon-rhodamyllysine-VP (Rhod-N3-dLVP) was obtained in a two-step procedure from the precursor 1-deamino[3(p-aminophenylalanine)]-LVP which was synthesized by a solid phase technique. The rat antidiuretic activity of this compound was 0.34 +/- 0.3 U/mg. Although both Rhod-N3-dLVP and its congener without a rhodamine label, N3-dLVP, did not have any hydroosmotic activity in the isolated toad urinary bladder in the absence of UV light, after UV irradiation they increased both urea and water transport across the bladder wall. Moreover, these permeability effects of Rhod-N3-dLVP persisted during prolonged and repeated periods of washout, suggesting that the photoproducts of this analog had formed covalent complexes with toad bladder receptors. Binding of Rhod-N3-dLVP was inhibited when photolysis was carried out in the presence of 1-deamino-LVP. These studies suggest that Rhod-N3-dLVP has the requisite biological properties to serve as a tool for the localization by fluorescence microscopy of VP receptors in various target tissues.