[Applications and challenges of large language models in critical care medicine]

The rapid development of big data methods and technologies has provided more and more new ideas and methods for clinical diagnosis and treatment. The emergence of large language models (LLM) has made it possible for human-computer interactive dialogues and applications in complex medical scenarios. Critical care medicine is a process of continuous dynamic targeted treatment. The huge data generated in this process needs to be integrated and optimized through models for clinical application, interaction in teaching simulation, and assistance in scientific research. Using the LLM represented by generative pre-trained transformer ChatGPT can initially realize the application in the diagnosis of severe diseases, the prediction of death risk and the management of medical records. At the same time, the time and space limitations, illusions and ethical and moral issues of ChatGPT emerged as the times require. In the future, it is undeniable that it may play a huge role in the diagnosis and treatment of critical care medicine, but the current application should be combined with more clinical knowledge reserves of critical care medicine to carefully judge its conclusions.

Identification, validation and biological characterisation of novel glioblastoma tumour microenvironment subtypes: implications for precision immunotherapy

BACKGROUND

New precision medicine therapies are urgently required for glioblastoma (GBM). However, to date, efforts to subtype patients based on molecular profiles have failed to direct treatment strategies. We hypothesised that interrogation of the GBM tumour microenvironment (TME) and identification of novel TME-specific subtypes could inform new precision immunotherapy treatment strategies.

MATERIALS AND METHODS

A refined and validated microenvironment cell population (MCP) counter method was applied to >800 GBM patient tumours (GBM-MCP-counter). Specifically, partition around medoids (PAM) clustering of GBM-MCP-counter scores in the GLIOTRAIN discovery cohort identified three novel patient clusters, uniquely characterised by TME composition, functional orientation markers and immune checkpoint proteins. Validation was carried out in three independent GBM-RNA-seq datasets. Neoantigen, mutational and gene ontology analysis identified mutations and uniquely altered pathways across subtypes. The longitudinal Glioma Longitudinal AnalySiS (GLASS) cohort and three immunotherapy clinical trial cohorts [treatment with neoadjuvant/adjuvant anti-programmed cell death protein 1 (PD-1) or PSVRIPO] were further interrogated to assess subtype alterations between primary and recurrent tumours and to assess the utility of TME classifiers as immunotherapy biomarkers.

RESULTS

TME^High tumours (30%) displayed elevated lymphocyte, myeloid cell immune checkpoint, programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 transcripts. TME^High/mesenchymal+ patients featured tertiary lymphoid structures. TME^Med (46%) tumours were enriched for endothelial cell gene expression profiles and displayed heterogeneous immune populations. TME^Low (24%) tumours were manifest as an 'immune-desert' group. TME subtype transitions upon recurrence were identified in the longitudinal GLASS cohort. Assessment of GBM immunotherapy trial datasets revealed that TME^High patients receiving neoadjuvant anti-PD-1 had significantly increased overall survival (P = 0.04). Moreover, TME^High patients treated with adjuvant anti-PD-1 or oncolytic virus (PVSRIPO) showed a trend towards improved survival.

CONCLUSIONS

We have established a novel TME-based classification system for application in intracranial malignancies. TME subtypes represent canonical 'termini a quo' (starting points) to support an improved precision immunotherapy treatment approach.

POS1368 DIVERSITY OF HEMODYNAMIC TYPES IN CONNECTIVE TISSUE DISEASE ASSOCIATED PULMONARY HYPERTENSION: MORE THAN A SUBGROUP OF PULMONARY ARTERIAL HYPERTENSION

Background

Connective tissue disease (CTD) associated pulmonary hypertension (PH) is classified as a subgroup of WHO group 1 PH, also called pulmonary arterial hypertension (PAH). However, not all CTD-PH fit the hemodynamic definition of PAH. This study investigates the diversity of hemodynamical types of CTD-PH, their different clinical characteristics and outcomes.

Objectives

This study investigates the diversity of hemodynamical types of CTD-PH, their different clinical characteristics and outcomes.

Methods

We performed a retrospective cohort study. CTD-PH patients underwent right heart catheterization (RHC) were enrolled and divided into WHO group1 PH, WHO group 2 PH and high output PH (PVR<3WU and PAWP<15mmHg) according to hemodynamic features. Patients with obvious lung diseases, left heart disease and pulmonary embolism were excluded. Baseline characteristics, inflammatory markers, autoantibodies, cardiac function status, echocardiogram parameters, hemodynamics and survival rates were compared.

Results

207 CTD-PH patients were included, including 139 in WHO group 1 PH, 36 in WHO group 2 PH and 32 in high output PH. Incidence of anti-ribonucleoprotein antibody was lower in WHO Group 2 PH. High output PH is less severe, presenting lower NT-proBNP level, better WHO functional class, lower mPAP and PVR, higher cardiac output, and less cardiac remodeling. Among patients with elevated PAWP, combine pre& post-capillary PH had higher mPAP and larger right ventricle diameter. Association of mild to moderate interstitial lung disease didn’t show significant difference in disease characteristics. Short-term survival was significantly worse in WHO group 2 PH, yet 5-year survival rates didn’t differ between groups.

Conclusion

Pre-capillary PH is not the only hemodynamic type of CTD-PH. Different types of CTD-PH present different clinical phenotypes and outcome. Carefully phenotyping PH in CTD-PH patients is important.

Disclosure of Interests

None declared

[Evaluation of human milk feeding in hospitalized very low and extremely low birth weight infants]

Objective: To investigate the current situation of human milk (HM) feeding in hospitalized very low and extremely low birth weight infants. Methods: The study retrospectively extracted the data of 601 infants with birth weight <1 500 g, and admitted within 24 hours after birth to the Neonatal Intensive Care Unit of Nanjing Maternity and Child Health Care Hospital from January 2016 to December 2018. The infants were grouped into exclusive mother's-own-milk (MOM) group, donor human milk (DHM) group (partial or none MOM), and mixed (HM and formula) feeding group according to the feeding strategy. Qualitative and quantitative variables in the three groups were compared with One-way ANOVA, Kruskal-Wallis test, Chi-square test or Fisher exact test. Kappa and McNemar test were used for consistency testing. Results: Among the 601 infants (309 boys and 292 girls), 6 (1.0%) infants had never been fed with MOM. The gestational age and birth weight were (29.3±1.9) weeks and 1 260(1 115, 1 400) g in 601 infants. A total of 8 (1.3%) infants were grouped into MOM group, 542 (90.2%) were grouped into DHM group, and 51 (8.5%) were grouped into mixed feeding group. The percentage of enteral feedings with MOM in the stage of hospitalization 1-7 d, 8-14 d and 15-28 d were 73.6% (42.9%, 86.7%), 97.5% (78.6%, 100.0%) and 99.3% (93.0%, 100.0%), respectively (H=414.95, P<0.01), and the pairwise comparison suggested that the stage of hospitalization 1-7 d was the lowest (adjusted both P<0.05). The average weight adjusted daily dose of MOM were 9.7 (4.3, 18.2), 59.1 (26.5, 93.5) and 116.0 (60.3, 142.6) ml/(kg·d) in the stage of hospitalization 1-7 d, 8-14 d and 15-28 d, respectively (H=759.75, P<0.01), and the pairwise comparison suggested that the stage of hospitalization 1-7 d was the lowest (adjusted both P<0.05). The weight adjusted daily dose of MOM in exclusive MOM group, DHM and Mixed feeding group were 95.2 (40.0, 117.2), 82.9(53.6, 103.1) and 55.7 (16.6, 97.5) ml/(kg·d), respectively (H=10.78, P=0.005).Additionally, the percentage and weight adjusted daily dose of MOM showed a general consistency of 0.703 (P>0.05, Kappa=0.408). Conclusions: The rate of exclusive MOM feeding is low, especially during the first 7 days of hospitalization. The percentage of total enteral feedings with MOM and the average weight adjusted daily dose of MOM can well evaluate the situation of HM feeding during hospitalization quantitively.

[Acute respiratory failure due to Pneumocystis pneumonia in connective tissue disease patients: clinical manifestation and prognostic factors related to hospital mortality]

Objective: To investigate the clinical manifestations and prognostic factors of hospital death in connective tissue disease patients with acute respiratory failure caused by pneumocystis pneumonia (PCP) admitted to two medical intensive care units(MICU). Methods: A retrospective review was conducted for all connective tissue disease (CTD) patients with acute respiratory failure from PCP in MICU of 2 academic medical centers between 2010 and 2015. The patients were divided into survivors and non-survivors. Demographic and clinical data, including laboratory, radiological and microbiological findings, as well as therapy, clinical course, mortality and prognostic factors of hospital mortality were included in the analysis. Logistic regression models were used to determine the effect of prognostic factors on hospital death after adjusting for covariates of which the p values were less than 0.1. Results: A total of 41 patients with connective tissue disease were identified. The PaO(2)/FiO(2) ratio (PFR) on ICU admission was 120 mmHg(55-180 mmHg, 1 mmHg=0.133 kPa). Common clinical features included dyspnea (90.2%, 37/41), fever (87.8%, 36/41) and dry cough(65.9%, 30/41). 58.5%(24/41) and 17.1%(7/41) patients were co-infected by CMV and aspergillus, respectively. The overall mortality rate was 75.6%(31/41). Compared with survivors, the age, APACHEⅡ score and incidence of barotrauma in non-survivors were higher (39±17 vs 58±15, t=3.018, P=0.002), (15±6 vs 19±5, t=2.528, P=0.019), (0/10 vs 12/31, χ(2)=5.473, P=0.021), while PFR on ICU admission was lower in non-survivors (172±68 vs 116±49, t=-1.893, P=0.007). Logistic analysis showed that PFR on ICU admission was the independent risk factor for hospital death (OR=1.004, 95%CI: 1.002-1.006, P=0.048). Conclusions: Mortality rate among patients with acute respiratory failure secondary to CTD related PCP is still high, and the poor prognostic factors of hospital mortality included PFR on ICU admission and barotrauma.

[Pigmented extramammary Paget's disease accompanied with condyloma acuminatum: a case report]

Pigmented extramammary Paget's disease (PEMPD) is an uncommon intraepithelial adenocarcinoma and a rare variant of Paget's disease, characterized as a superficial pigmented scaly macule clinically and an increased number of melanocytes scattered between the Paget's cells histologically. So it may be confused clinically and histologically with melanocytic tumors, dermatitis and other dermatoses. Different therapeutic attitudes are required in this case of adenocarcinoma in situ as opposed to melanoma and dermatitis. Condyloma acuminatum (CA) is a common sexually transmitted disease caused by human papilloma virus infection, which is also called as genital warts. In this article, we first reported a case of a 65-year-old Chinese man who had pigmented extramammary Paget's disease complicated with CA. This patient presented with verrucous papules on the scrotum for 3.5 years, infiltrative erythema with itch on the mons pubis for 3 years, and scrotum and penis involved gradually for 4 months. Physical examination showed a 8 cm×10 cm dark red patch on the upper part of the scrotum, penis and mons pubis, as well as few maculopapules and nodules. Histopathologic examination of the lesion on the scrotum revealed a focus of Paget's disease, characterized by the presence of large round cells with abundant pale or granular/dusty cytoplasm, pleomorphic vesicular nuclei and prominent nucleoli (Paget's cells), while the histology of the verrucous lesion was consistent with CA. Immunohistochemistry was performed, which showed diffuse positive staining with CK, CEA, PAS, CK20, EMA, CK7, and Ki-67 (40%), HER2 in Paget's cells and negative with P53, P16, CK5/6, S100, MelanA, HMB45, estrogen receptor, progesterone receptor, and gross cystic disease flid protein 15 (GCDFP15). Human papillomavirus-11 (HPV-11) was positive by genotyping using gene amplification in the lesion of scrotum. According to clinical features and laboratory findings, a diagnosis of PEMPD complicated with CA was made. Local excision of the lesion was performed and sent for histological examination, with all margins clear of tumor. Both aforementioned diseases often occur in the vulva. Even so, it has been rarely reported coexisting of the above two diseases, of which the clinical significance and association are also unclear. In this article, we also reviewed the literature relating to PEMPD, and on this basis, the profile of this disease is discussed including its pathogenesis, clinical manifestation, diagnosis, treatment and advances. Due to PEMPD occasionally accompanied with an underlying carcinoma, it's essential to make an accurate diagnosis. Besides, review of the literature reveals that pigmented variant of Paget's disease could be initially misdiagnosed as melanocytic tumors and other dermatoses unless the entity is considered in the differential diagnosis and additional confirmatory studies are performed.

Robust, tunable, and high purity triggered single photon source at room temperature using a nitrogen-vacancy defect in diamond in an open microcavity

We report progress in the development of tunable room temperature triggered single photon sources based on single nitrogen-vacancy (NV) centres in nanodiamond coupled to open access optical micro-cavities. The feeding of fluorescence from an NV centre into the cavity mode increases the spectral density of the emission and results in an output stream of triggered single photons with spectral line width of order 1 nm, tunable in the range 640 - 700 nm. We record single photon purities exceeding 96% and estimated device efficiencies up to 3%. We compare performance using plano-concave microcavities with radii of curvature from 25 μm to 4 μm and show that up to 17% of the total emission is fed into the TEM₀₀ mode. Pulsed Hanbury-Brown Twiss (HBT) interferometry shows that an improvement in single photon purity is facilitated due to the increased spectral density.

[Left atrial appendage volume is a valuable predictor of atrial fibrillation recurrence after radiofrequency catheter ablation]

Objective: To investigate the association between the left atrial appendage (LAA) volume and atrial fibrillation (AF) recurrence after radiofrequency catheter ablation. Methods: We prospectively enrolled sixty-two patients with AF (40 cases with paroxysmal AF, 22 cases with persistent AF) who successfully underwent a first AF catheter ablation and had performed contrast-enhanced cardiac computed tomography (CT) prior to the procedure to measure LAA volumes in our hospital from January 2012 to August 2015. Circumferential pulmonary vein isolation was performed under the guidance of three-dimension mapping system (CARTO system). Linear ablation or ablation of complex fractioned atrial electrograms was also undertaken if necessary. All patients were followed up at the 3rd, 6th and 12th months after ablation by 24-hour ambulatory Holter monitoring, and were divided into the non-recurrence group (n=42) and the AF recurrence group (n=20). Univariate and multivariate Cox proportional hazards regression analysis were used to assess the factors related to AF recurrence. The receiver operating characteristic (ROC) curve was calculated to assess the best cut-off value of LAA volume to predict AF recurrence. Kaplan-Meier method was used to evaluate the rate of freedom from AF recurrence. Results: Mean LAA volume in all patients was (9.5±3.6)ml. AF recurrence occurred in 20 patients (32%) during the follow-up period. The LAA volume was significantly larger in the AF recurrence group than in the non-recurrence group ((11.5±3.8)ml vs. (8.3±3.1)ml, P=0.002). In the univariate regression analysis, LAA volume (HR=1.36, 95%CI 1.14-1.82, P<0.001), persistent AF (HR=4.43, 95%CI 1.52-12.06, P<0.001) and hypertension (HR=1.61, 95%CI 1.13-2.04, P=0.041) were risk factors of AF recurrence. However, multivariate regression analysis revealed that LAA volume (HR=1.32, 95%CI 1.12-1.51, P<0.001) and persistent AF (HR=4.22, 95% CI 1.48-11.05, P<0.001) were independent predictors for AF recurrence after ablation. The receiver operating characteristic (ROC) curve analysis revealed that a LAA volume >8.80 ml was associated with AF recurrence after ablation (sensitivity: 94% and specificity: 66%, area under the curve=0.76). Kaplan-Meier analysis showed a lower rate free from AF recurrence in the group with LAA volume >8.80 ml (P<0.001). Conclusion: Larger LAA volume is associated with AF recurrence after catheter ablation in patients with AF. A LAA volume greater than 8.80 ml could be used to predict AF recurrence after ablation.

[The 455th case: swollen leg, jaundice and mental disturbance]

A 17-year-old young man with a history of swollen leg and intermittent jaundice was presented to Peking Union Medical College Hospital with acute fever and mental disturbance. He developed deep venous thrombosis, acute myocardial infarction and plantar skin necrosis during the past four years, and was presented with an acute episode of fever, thrombocytopenia, acute kidney injury, acute myocardial infarction, mental disturbance, and obstructive jaundice. Laboratory tests showed schistocytes on peripheral blood smear.High titer of antiphospholipid antibodies was detected.Strikingly, the activity of a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13)was significantly decreased without the production of inhibitors. Images indicated stenosis of the common bile duct, common hepatic duct, and cystic duct, which caused dilation of bile ducts and the gall bladder. Corticosteroids and anticoagulation therapy were effective at first, but the disease relapsedonce the corticosteroids tapered down. Plasma exchange was administrated for 17 times, which was effective temporarily during this episode. Methylprednisolone pulse therapy, intravenous immunoglobulin, rituximab, anticoagulation therapy, and bile drainage, were all tried but still could not control the disease. The patient's family agreed to withdraw treatment after he developed septic shock.

Pharmacometabolomic Assessments of Atenolol and Hydrochlorothiazide Treatment Reveal Novel Drug Response Phenotypes

Achieving hypertension (HTN) control and mitigating the adverse health effects associated with HTN continues to be a global challenge. Some individuals respond poorly to current HTN therapies, and mechanisms for response variation remain poorly understood. We used a nontargeted metabolomics approach (gas chromatography time-of-flight/mass spectrometry gas chromatography time-of-flight/mass spectrometry) measuring 489 metabolites to characterize metabolite signatures associated with treatment response to anti-HTN drugs, atenolol (ATEN), and hydrochlorothiazide (HCTZ), in white and black participants with uncomplicated HTN enrolled in the Pharmacogenomic Evaluation of Antihypertensive Responses study. Metabolite profiles were significantly different between races, and metabolite responses associated with home diastolic blood pressure (HDBP) response were identified. Metabolite pathway analyses identified gluconeogenesis, plasmalogen synthesis, and tryptophan metabolism increases in white participants treated with HCTZ (P < 0.05). Furthermore, we developed predictive models from metabolite signatures of HDBP treatment response (P < 1 × 10(-5)). As part of a quantitative systems pharmacology approach, the metabolites identified herein may serve as biomarkers for improving treatment decisions and elucidating mechanisms driving HTN treatment responses.

Genome-wide discovery of genetic variants affecting tamoxifen sensitivity and their clinical and functional validation

BACKGROUND

Beyond estrogen receptor (ER), there are no validated predictors for tamoxifen (TAM) efficacy and toxicity. We utilized a genome-wide cell-based model to comprehensively evaluate genetic variants for their contribution to cellular sensitivity to TAM.

DESIGN

Our discovery model incorporates multidimensional datasets, including genome-wide genotype, gene expression, and endoxifen-induced cellular growth inhibition in the International HapMap lymphoblastoid cell lines (LCLs). Genome-wide findings were further evaluated in NCI60 cancer cell lines. Gene knock-down experiments were performed in four breast cancer cell lines. Genetic variants identified in the cell-based model were examined in 245 Caucasian breast cancer patients who underwent TAM treatment.

RESULTS

We identified seven novel single-nucleotide polymorphisms (SNPs) associated with endoxifen sensitivity through the expression of 10 genes using the genome-wide integrative analysis. All 10 genes identified in LCLs were associated with TAM sensitivity in NCI60 cancer cell lines, including USP7. USP7 knock-down resulted in increasing resistance to TAM in four breast cancer cell lines tested, which is consistent with the finding in LCLs and in the NCI60 cells. Furthermore, we identified SNPs that were associated with TAM-induced toxicities in breast cancer patients, after adjusting for other clinical factors.

CONCLUSION

Our work demonstrates the utility of a cell-based model in genome-wide identification of pharmacogenomic markers.

Competition among memes in a world with limited attention

The wide adoption of social media has increased the competition among ideas for our finite attention. We employ a parsimonious agent-based model to study whether such a competition may affect the popularity of different memes, the diversity of information we are exposed to, and the fading of our collective interests for specific topics. Agents share messages on a social network but can only pay attention to a portion of the information they receive. In the emerging dynamics of information diffusion, a few memes go viral while most do not. The predictions of our model are consistent with empirical data from Twitter, a popular microblogging platform. Surprisingly, we can explain the massive heterogeneity in the popularity and persistence of memes as deriving from a combination of the competition for our limited attention and the structure of the social network, without the need to assume different intrinsic values among ideas.

Loss of bacterial diversity during antibiotic treatment of intubated patients colonized with Pseudomonas aeruginosa

Management of airway infections caused by Pseudomonas aeruginosa is a serious clinical challenge, but little is known about the microbial ecology of airway infections in intubated patients. We analyzed bacterial diversity in endotracheal aspirates obtained from intubated patients colonized by P. aeruginosa by using 16S rRNA clone libraries and microarrays (PhyloChip) to determine changes in bacterial community compositions during antibiotic treatment. Bacterial 16S rRNA genes were absent from aspirates obtained from patients briefly intubated for elective surgery but were detected by PCR in samples from all patients intubated for longer periods. Sequencing of 16S rRNA clone libraries demonstrated the presence of many orally, nasally, and gastrointestinally associated bacteria, including known pathogens, in the lungs of patients colonized with P. aeruginosa. PhyloChip analysis detected the same organisms and many additional bacterial groups present at low abundance that were not detected in clone libraries. For each patient, both culture-independent methods showed that bacterial diversity decreased following the administration of antibiotics, and communities became dominated by a pulmonary pathogen. P. aeruginosa became the dominant species in six of seven patients studied, despite treatment of five of these six with antibiotics to which it was sensitive in vitro. Our data demonstrate that the loss of bacterial diversity under antibiotic selection is highly associated with the development of pneumonia in ventilated patients colonized with P. aeruginosa. Interestingly, PhyloChip analysis demonstrated reciprocal changes in abundance between P. aeruginosa and the class Bacilli, suggesting that these groups may compete for a similar ecological niche and suggesting possible mechanisms through which the loss of microbial diversity may directly contribute to pathogen selection and persistence.

Intervertebral administration of 153Samarium with kyphoplasty for vertebral metastases

13136

Background: Kyphoplasty is an effective procedure to alleviate pain in metastatic vertebrae. 153Samarium-EDTMP (153Sm) is used for palliative treatment of multiple bone metastases. The hematological toxicity is the main limiting factor. Objectives: Study the feasibility of intervertebral administration of 153 SM with Kyphoplasty. Assess procedure related morbidities specifically haematological since a direct vertebral route is planned though to a much smaller dose. Methods: IRB approval for an off label use of 153Sm-EDTMP was obtained. Six patients with documented vertebral bone metastasis and pathological compression fractures were studied (Thoracic in 2 and lumbar in 4). Primary cancer was lung in 2, prostate (1), maxillary sinus (1), myeloma (1) and colon (1). Serial dilution of 153 SM was performed to obtain 2 mci/1ml. Kyphoplasty procedure was carried out using the known protocol. 2 mCi of 153Sm was admixed with the bone cement and administered under tight radiation safety measures. Serial nuclear body scans were obtained. Pain assessment was evaluated using analog pain score at 1, 7 and 30 days. Serial blood counts are followed. Results: All patients tolerated procedure well. No immediate procedure(s) related morbidities were noted. One case was not technically satisfactory and no significant uptake was detected in the injected vertebra. Nuclear scan done on 0 revealed excellent radiotracer uptake in the other 5 vertebrae injected. The absorbed radiotracer was seen to target other skeletal metastatic lesions in 2 patients. There was no significant change in WBC, HCT or Platelets seen in blood counts obtained over one month post-procedure. Except for the first patient, no appreciable radiation leakage was encountered. Pain score was reduced from a mean of 8.5 to 3.2 during the first week and was maintained below score of 4 at one month assessment. Conclusions: The combination of intervertebral administration of 153SM and Kyphoplasty seems to be well tolerated. No haematological side effects were encountered; probably due to the use of only 2 mci compared to over 70 mci in intravenous administration. Pain control seems to be satisfactory at areas treated. Analysis of procedure related radiological changes is underway.

No significant financial relationships to disclose.

Excretory nitrogen metabolism in the Chinese fire-belly newt Cynops orientalis in water, on land, or in high concentrations of environmental ammonia

The Chinese fire-belly newt Cynops orientalis reverts to an aquatic mode of living when sexually mature. Despite living in water, sexually mature C. orientalis maintained high capacity for hepatic urea synthesis. However, it had a lower rate of urea production than other terrestrial amphibians because endogenous ammonia could diffuse out to the external medium as NH3. This conserves cellular energy because urea synthesis is energetically expensive. Simultaneously, C. orientalis also reduced the rate of urea excretion, and excreted 33% of the total nitrogenous waste as ammonia. Upon exposure to land, C. orientalis increased the rate of urea synthesis from accumulating endogenous ammonia. The increased rate of urea synthesis was within the inherent capacity of the hepatic ornithine-urea cycle; there was no induction of hepatic carbamoyl phosphate synthetase or ornithine transcarbamoylase activities and there was no reduction in ammonia production. When exposed to water containing 75 mmol.l(-1) NH4Cl, the rates of both urea synthesis and urea excretion increased. Under such experimental conditions, the ornithine-urea cycle may be operating close to its limit; glutamine began to accumulate in the body, and endogenous ammonia production via amino acid catabolism was reduced.

[Effects of XW630 on mechanical properties and trabecular structure parameters of bone tissue in ovariectomized rats]

OBJECTIVE

The study aimed at investigating the effects of a new anti-osteoporotic drug, XW630 on promoting the osteogenic activity of bone tissue in ovariectomized rats.

METHODS

Thirty-six female SD rats, three months old, were randomly divided into four groups: sham-operated group (sham), the ovariectomized group (OVX), the esterone-therapy group (OVX + CFT) and the XW630-therapy group (OVX + XW630). Three rats in each group were killed on the 30th, 60th, and 90th day after the operation. The femur of one side was taken for the three-point bending resistance test, and the bilateral tibias were taken for the HE stain and scanning electronic microscopy (SEM) examination.

RESULTS

The HE and SEM results indicated that the bone loss appeared in the OVX group 30 days after the operation, which lasted for the whole observing period. While after application of ester-one and XW630, there were different degrees of bone repairing around the trabeculae, and the osteogenic activity was obviously active in the XW630 group than that in the esterone group. During the experimental period, the three-point bending resistance of the OVX group gradually decreased and there was a significant difference compared with that of the sham group (P < 0.01), while the three-point bending resistance of the two therapy group gradually increased and there was significant difference between the OVX group and the XW630 group (P < 0.05 and P < 0.01).

CONCLUSION

XW630 can effectively promote osteogenic action and prevent osteoporostic fracture in ovariectomized rats.

[Regulation of XW630 on TGF-beta 1 and collagen I gene expression in osteoblasts]

OBJECTIVE

The purpose of this part of study was to investigate the mechanism of a new anti-osteoporotic drug, XW630 on promoting osteogenic activity.

METHODS

Total RNA were isolated from osteoblasts of the mice after the reaction with XW630 in 24 and 72 hours, that were hybridized with the extracted and digoxigenin-labeled TGF-beta 1 and the collagen I cDNA probes.

RESULTS

XW630 significantly promoted TGF-beta 1 and collagen I gene expression in osteoblasts, and this drug was superior than other two kinds of estrogen in promoting osteogenic activity (P < 0.05).

CONCLUSION

XW630 promote osteogenic activity of osteoblasts, probably by enhancing the mRNA expression of TGF-beta 1 and collagen I.

Contribution of individual sorbents to the control of heavy metal activity in sandy soil

A multisurface model is used to evaluate the contribution of various sorption surfaces to the control of heavy metal activity in sandy soil samples at pH 3.7-6.1 with different sorbent contents. This multisurface model considers soil as a set of independent sorption surfaces, i.e. organic matter (NICA-Donnan), clay silicate (Donnan), and iron hydroxides (DDL, CD-MUSIC). The activities of Cu2+, Cd2+, Zn2+, Ni2+, and Pb2+ in equilibrium with the soil have been measured using a Donnan membrane technique. The metal activities predicted by the model agree with those measured reasonably well over a wide concentration range for all the metals of interest except for Pb. The modeling results suggest that soil organic matter is the most important sorbent that controls the activity of Cu2+, Cd2+, Zn2+, and Ni2+ in these sandy soils. When metal loading is high in comparison with soil organic matter content, the contribution of clay silicates to metal binding becomes more important. Adsorption to iron hydroxides is found not significant in these samples for Cu, Cd, Zn, and Ni. However, for Pb the model estimates strong adsorption on iron hydroxides. The model predicts that acidification will not only lead to increased solution concentrations but also to a shift toward more nonspecific cation-exchange type binding especially for the metals Cd, Zn, and Ni. Lowering the pH has led to a loss of 56% of Cd, 69% of Zn, and 66% of Ni during 16 years due to increased leaching.

[Clinical study on women with amenorrhea after levonorgestrel intrauterine system]

OBJECTIVE

To study the 5 years contraceptive efficacy of levonorgestrel intrauterine system (LNG-IUS) and the ovarian functions in amenorrhea women.

METHODS

LNG-IUS and TCu 380A IUD were randomly inserted in 2 groups of women, 50 each. Women were followed annually for 5 years. Serum follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), estradiol (E2), and T levels in 14 women with amenorrhea, and endometrial biopsies were obtained in 9 cases.

RESULTS

By the end of 5 years, there were 2 pregnancies in TCu 380A group, but none in LNG-IUS group; and 24 amenorrhea cases in LNG-IUS. The 5 year cumulative continuation rates were 24% for LNG-IUS and 78% for TCu 380A (P < 0.001). In the 14 women with amenorrhea, the average serum concentrations were not significantly different from that of the normal controls. Histological study showed endometrial atrophy or a few secretory glands.

CONCLUSIONS

LNG-IUS is a highly effective and safe contraceptive measure. Oligomenorrhea and amenorrhea caused by the local effects of LNG were reversible and did no harm to women's health. However, comprehensive consultation provided to women before insertion is of utmost importance for continuation use.