Objective: To identify the risk factors in mortality of pediatric acute respiratory distress syndrome (PARDS) in pediatric intensive care unit (PICU). Methods: Second analysis of the data collected in the "efficacy of pulmonary surfactant (PS) in the treatment of children with moderate to severe PARDS" program. Retrospective case summary of the risk factors of mortality of children with moderate to severe PARDS who admitted in 14 participating tertiary PICU between December 2016 to December 2021. Differences in general condition, underlying diseases, oxygenation index, and mechanical ventilation were compared after the group was divided by survival at PICU discharge. When comparing between groups, the Mann-Whitney U test was used for measurement data, and the chi-square test was used for counting data. Receiver Operating Characteristic (ROC) curves were used to assess the accuracy of oxygen index (OI) in predicting mortality. Multivariate Logistic regression analysis was used to identify the risk factors for mortality. Results: Among 101 children with moderate to severe PARDS, 63 (62.4%) were males, 38 (37.6%) were females, aged (12±8) months. There were 23 cases in the non-survival group and 78 cases in the survival group. The combined rates of underlying diseases (52.2% (12/23) vs. 29.5% (23/78), χ²=4.04, P=0.045) and immune deficiency (30.4% (7/23) vs. 11.5% (9/78), χ²=4.76, P=0.029) in non-survival patients were significantly higher than those in survival patients, while the use of pulmonary surfactant (PS) was significantly lower (8.7% (2/23) vs. 41.0% (32/78), χ²=8.31, P=0.004). No significant differences existed in age, sex, pediatric critical illness score, etiology of PARDS, mechanical ventilation mode and fluid balance within 72 h (all P>0.05). OI on the first day (11.9(8.3, 17.1) vs.15.5(11.7, 23.0)), the second day (10.1(7.6, 16.6) vs.14.8(9.3, 26.2)) and the third day (9.2(6.6, 16.6) vs. 16.7(11.2, 31.4)) after PARDS identified were all higher in non-survival group compared to survival group (Z=-2.70, -2.52, -3.79 respectively, all P<0.05), and the improvement of OI in non-survival group was worse (0.03(-0.32, 0.31) vs. 0.32(-0.02, 0.56), Z=-2.49, P=0.013). ROC curve analysis showed that the OI on the thind day was more appropriate in predicting in-hospital mortality (area under the curve= 0.76, standard error 0.05,95%CI 0.65-0.87,P<0.001). When OI was set at 11.1, the sensitivity was 78.3% (95%CI 58.1%-90.3%), and the specificity was 60.3% (95%CI 49.2%-70.4%). Multivariate Logistic regression analysis showed that after adjusting for age, sex, pediatric critical illness score and fluid load within 72 h, no use of PS (OR=11.26, 95%CI 2.19-57.95, P=0.004), OI value on the third day (OR=7.93, 95%CI 1.51-41.69, P=0.014), and companied with immunodeficiency (OR=4.72, 95%CI 1.17-19.02, P=0.029) were independent risk factors for mortality in children with PARDS. Conclusions: The mortality of patients with moderate to severe PARDS is high, and immunodeficiency, no use of PS and OI on the third day after PARDS identified are the independent risk factors related to mortality. The OI on the third day after PARDS identified could be used to predict mortality.
Female ; Male ; Humans ; Child, Preschool ; Infant ; Child ; Critical Illness ; Pulmonary Surfactants/therapeutic use* ; Retrospective Studies ; Risk Factors ; Respiratory Distress Syndrome/therapy*

Objective: Total neoadjuvant therapy has been used to improve tumor responses and prevent distant metastases in patients with locally advanced rectal cancer (LARC). Patients with complete clinical responses (cCR) then have the option of choosing a watch and wait (W&W) strategy and organ preservation. It has recently been shown that hypofractionated radiotherapy has better synergistic effects with PD-1/PD-L1 inhibitors than does conventionally fractionated radiotherapy, increasing the sensitivity of microsatellite stable (MSS) colorectal cancer to immunotherapy. Thus, in this trial we aimed to determine whether total neoadjuvant therapy comprising short-course radiotherapy (SCRT) combined with a PD-1 inhibitor improves the degree of tumor regression in patients with LARC. Methods: TORCH is a prospective, multicenter, randomized, phase II trial (TORCH Registration No. NCT04518280). Patients with LARC (T3-4/N+M0, distance from anus ≤10 cm) are eligible and are randomly assigned to consolidation or induction arms. Those in the consolidation arm receive SCRT (25Gy/5 Fx), followed by six cycles of toripalimab plus capecitabine and oxaliplatin (ToriCAPOX). Those in the induction arm receive two cycles of ToriCAPOX, then undergo SCRT, followed by four cycles of ToriCAPOX. Patients in both groups undergo total mesorectal excision (TME) or can choose a W&W strategy if cCR has been achieved. The primary endpoint is the complete response rate (CR, pathological complete response [pCR] plus continuous cCR for more than 1 year). The secondary endpoints include rates of Grade 3-4 acute adverse effects (AEs) etc. Results: Up to 30 September 2022, 62 patients attending our center were enrolled (Consolidation arm: 34, Induction arm:28). Their median age was 53 (27-69) years. Fifty-nine of them had MSS/pMMR type cancer (95.2%), and only three MSI-H/dMMR. Additionally, 55 patients (88.7%) had Stage III disease. The following important characteristics were distributed as follows: lower location (≤5 cm from anus, 48/62, 77.4%), deeper invasion by primary lesion (cT4 7/62, 11.3%; mesorectal fascia involved 17/62, 27.4%), and high risk of distant metastasis (cN2 26/62, 41.9%; EMVI+ 11/62, 17.7%). All 62 patients completed the SCRT and at least five cycles of ToriCAPOX, 52/62 (83.9%) completing six cycles of ToriCAPOX. Finally, 29 patients achieved cCR (46.8%, 29/62), 18 of whom decided to adopt a W&W strategy. TME was performed on 32 patients. Pathological examination showed 18 had achieved pCR, four TRG 1, and 10 TRG 2-3. The three patients with MSI-H disease all achieved cCR. One of these patients was found to have pCR after surgery whereas the other two adopted a W&W strategy. Thus, the pCR and CR rates were 56.2% (18/32) and 58.1% (36/62), respectively. The TRG 0-1 rate was 68.8% (22/32). The most common non-hematologic AEs were poor appetite (49/60, 81.7%), numbness (49/60, 81.7%), nausea (47/60, 78.3%) and asthenia (43/60, 71.7%); two patients did not complete this survey. The most common hematologic AEs were thrombocytopenia (48/62, 77.4%), anemia (47/62, 75.8%), leukopenia/neutropenia (44/62, 71.0%) and high transaminase (39/62, 62.9%). The main Grade III-IV AE was thrombocytopenia (22/62, 35.5%), with three patients (3/62, 4.8%) having Grade IV thrombocytopenia. No Grade V AEs were noted. Conclusions: SCRT-based total neoadjuvant therapy combined with toripalimab can achieve a surprisingly good CR rate in patients with LARC and thus has the potential to offer new treatment options for organ preservation in patients with MSS and lower-location rectal cancer. Meanwhile, the preliminary findings of a single center show good tolerability, the main Grade III-IV AE being thrombocytopenia. The significant efficacy and long-term prognostic benefit need to be determined by further follow-up.
Humans ; Middle Aged ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Chemoradiotherapy ; Immune Checkpoint Inhibitors/therapeutic use* ; Neoadjuvant Therapy ; Prospective Studies ; Rectal Neoplasms/pathology* ; Thrombocytopenia/drug therapy* ; Treatment Outcome ; Adult ; Aged

The aim of this study was to estimate the seroprevalence of immunoglobulin M (IgM) and G (IgG) antibodies against SARS-CoV-2 in asymptomatic people in Wuhan. This was a cross-sectional study, which enrolled 18,712 asymptomatic participants from 154 work units in Wuhan. Pearson Chi-square test,
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Viral/blood* ; COVID-19/immunology* ; Carrier State/immunology* ; Child ; Child, Preschool ; China/epidemiology* ; Coronavirus Nucleocapsid Proteins/immunology* ; Cross-Sectional Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Immunoglobulin M/blood* ; Male ; Middle Aged ; Occupations/classification* ; Phosphoproteins/immunology* ; SARS-CoV-2/immunology* ; Seroepidemiologic Studies ; Spike Glycoprotein, Coronavirus/immunology* ; Young Adult

BACKGROUND AND OBJECTIVE: Acute liver failure (ALF) is a type of disease with high mortality and rapid progression with no specific treatment methods currently available. Glucocorticoids exert beneficial clinical effects on therapy for ALF. However, the mechanism of this effect remains unclear and when to use glucocorticoids in patients with ALF is difficult to determine. The purpose of this study was to investigate the specific immunological mechanism of dexamethasone (Dex) on treatment of ALF induced by lipopolysaccharide (LPS)/D-galactosamine (D-GaIN) in mice. METHODS: Male C57BL/6 mice were given LPS and D-GaIN by intraperitoneal injection to establish an animal model of ALF. Dex was administrated to these mice and its therapeutic effect was observed. Hematoxylin and eosin (H&E) staining was used to determine liver pathology. Multicolor flow cytometry, cytometric bead array (CBA) method, and next-generation sequencing were performed to detect changes of messenger RNA (mRNA) in immune cells, cytokines, and Kupffer cells, respectively. RESULTS: A mouse model of ALF can be constructed successfully using LPS/D-GaIN, which causes a cytokine storm in early disease progression. Innate immune cells change markedly with progression of liver failure. Earlier use of Dex, at 0 h rather than 1 h, could significantly improve the progression of ALF induced by LPS/D-GaIN in mice. Numbers of innate immune cells, especially Kupffer cells and neutrophils, increased significantly in the Dex-treated group. In vivo experiments indicated that the therapeutic effect of Dex is exerted mainly via the glucocorticoid receptor (Gr). Sequencing of Kupffer cells revealed that Dex could increase mRNA transcription level of nuclear receptor subfamily 4 group A member 1 (Nr4a1), and that this effect disappeared after Gr inhibition. CONCLUSIONS In LPS/D-GaIN-induced ALF mice, early administration of Dex improved ALF by increasing the numbers of innate immune cells, especially Kupffer cells and neutrophils. Gr-dependent Nr4a1 upregulation in Kupffer cells may be an important ALF effect regulated by Dex in this process.
Animals ; Dexamethasone/therapeutic use* ; Disease Models, Animal ; Kupffer Cells/physiology* ; Liver Failure, Acute/pathology* ; Male ; Mice ; Mice, Inbred C57BL ; Nuclear Receptor Subfamily 4, Group A, Member 1/physiology* ; Receptors, Glucocorticoid/physiology*

Objective:To investigate the effect of dexmedetomidine on stress response and cellular immune function in patients undergoing radical resection of colon cancer during perioperative period.Methods: 96 cases of colon cancer undergoing radical resection were randomly divided into dexmedetomidine group(group D)and control group(group C).The group D was intubated with in-travenous infusion of dexmedetomidine 0.6 μg/kg,followed by intravenous infusion of 0.3 μg/(kg·h) at the end of the surgery,and the group C was given 0.9% saline at equal volume and rate.The venous blood of patients was collected before anesthesia induction,10 min(T0),immediate postoperative(T1),postoperative 24 h(T2)and postoperative 72 h(T3).Flow cytometry were used to detect T lym-phocyte subsets(CD3+,CD4+,CD8+,CD4+/CD8+)and the percentage of NK cells,and determination of norepinephrine(NE), epinephrine(E),cortisol(Cor),IL-6,IL-10 and TNF-α levels.Records of patients with T0,immediate intubation(Ta),T1,immediate extubation(Tb)of SBP,DBP,MAP,and postoperative adverse reactions were recorded.Results:The SBP,DBP and MAP of group C at Ta,T1,Tbwere significantly higher than that of T0and group D(P<0.05).Compared to those at T0,the levels of CD3+,CD4+,CD8+and CD4+/CD8 at T1and T2were significantly lower in both groups(P<0.05),and the levels of group C at T1,T2,T3were significantly lower than those in group D(P<0.05).The NK cells of group C at T1,T2were significantly lower than that of T0and group D(P<0.05).Compared to those at T0,the levels of IL-6,IL-10 and TNF-α at T1and T2were significantly higher in both groups(P<0.05), and the levels in group C were significantly higher than those in group D(P<0.05).The IL-6 and IL-10 of group C at T3were significantly higher than that of T0and group D(P<0.05).Compared to those at T0,the levels of NE,E and Cor at T1and T2were sig-nificantly higher in both groups(P<0.05),and the levels in group C were significantly higher than those in group D(P<0.05).The NE,E and Cor of group C at T3were significantly higher than that of T0and group D(P<0.05).The proportion of adverse reactions in group D was significantly lower than that in group C(χ2= 4.800,P= 0.028).Conclusion: Dexmedetomidine can inhibit the perioperative stress response and reduce the impact on immune function in patients undergoing radical resection of colon cancer.

OBJECTIVETo evaluate the high-resolution and color Doppler ultrasonographic (US) characteristics of cervical lymphadenopathy in patients with infectious mononucleosis.

METHODSHigh-resolution and color Doppler US were performed in 30 patients aged 2 to 30 years with a total of 59 palpable enlarged cervical lymph nodes due to infectious mononucleosis. The US characteristics of the nodes including shape,echotexture,hilum,border,matting,cystic necrosis,calcification and vascular pattern were assessed. Three patients received cervical lymph nodes biopsies.

RESULTSThe common US findings of cervical lymphadenopathy due to infectious mononucleosis were round shape (69.5%),bilateral distribution (96.7%),matting (83.3%) [even bilateral matting (66.6%)],indistinct margin (79.7%),absence of hilum (66.1%),heterogeneous echotecture (61.0%),and central hilar vascular pattern(89.8%). In 2 patients with absence of the echoic hilum,lymph nodes biopsies showed histological features including marked effacement of the normal architecture in the medullary region accompanied by a mixed proliferation of lymphocytes and histiocytes. In all infectious mononucleosis nodes with a hilum,85.0% had heterogeneously hypo/iso-echoic hila and indistinct demarcation to the cortex. One of them underwent lymph node biopsy and histological findings showed obvious dilation of the sinus oidal lumen and proliferation of histiocytes.

CONCLUSIONAlthough several ultrasonographic characteristics frequently present in the nodes of infectious mononucleosis are not specific,the combination of ultrasound findings may be valuable in differential diagnosis.

Adolescent ; Adult ; Calcinosis ; Child ; Child, Preschool ; Diagnosis, Differential ; Humans ; Infectious Mononucleosis ; Lymphatic Diseases ; diagnostic imaging ; Neck ; Ultrasonography ; Young Adult

ObjectiveTo investigate the effect of drinking brick tea with low-fluoride level on prevention of tea type fluorosis.MethodsHandahangacha,Hadayinggegacha,Dalainuoyi town,in Keshiketengqi Inner Mongolia endemic fluorosis area were selected as test points,and brick tea with fluoride [(204.5 ± 10.2),(308.2 ±15.4)mg/kg] was given for 12 months.Dental fluorosis,clinical skeletal fluorosis,and X-ray diagnosis of skeletalfluorosis [according to “Endemic Skeletal Fluorosis Diagnostic Criteria” (WS 192-2008)] of adults 20 to 70 years of age were examined and level of fluoride before and after the prevention trial,in brick tea,drinking water,milk tea and urine were tested (fluoride ion selective electrode method),and fluoride intake through tea was calculated.ResultsDetection rate of adult dental fluorosis in Handahangacha was 68.89％ (62/90),clinical detection of skeletal fluorosis was 55.32％ (52/94),and X-ray detection of skeletal fluorosis was 65.17％ (58/89); adult dental fluorosis detection rate in Hadayinggegacha was 54.84％(51/93),clinical detection of skeletal fluorosis was 65.69％(67/102),and X-ray detection rate of skeletal fluorosis was 61.36％ (54/88).Brick tea fluoride was (831.4 ±138.9),(864.3 ± 134.6)mg/kg before the prevention trial in Handahangacha and Hadayinggegacha,respectively,drinking water fluoride content was (0.27 ± 0.05),(0.54 ± 0.24)mg/L,fluoride content of milk tea was (216 ± 1.12),(2.82 ± 1.38)mg/L,adult urine fluoride content was (2.78 ± 1.57),(2.96 ± 1.80)mg/L,and fluoride intake through milk tea was (8.12 ± 5.84),(6.42 ± 5.04)mg/d,respectively; after the prevention trial the fluoride content of brick tea was (204.5 ± 10.2),(308.2 ± 15.4)mg/kg,fluoride content of drinking water (0.34 ± 0.11),(0.62 ± 0.30)mg/L,fluoride content of milk tea(0.97 ± 0.33),(1.83 ± 0.66)mg/L,fluoride content in urine(1.29 ± 0.55),( 1.47 ±0.62)mg/L,fluoride intake through milk tea (3.45 ± 2.05),(3.71 ± 2.07)mg/d,respectively; in Handahan and Hadayinggegacha after the prevention trial the fluoride in brick tea,milk tea,urine fluoride,and fluoride intake through milk tea was significantly lower than that before the trial (t =14.30,12.97 ;6.46,3.95;6.69,5.72;6.27,3.57,all P ＜ 0.01 ).Fluoride intake in Handahangacha through milk tea was within the state heath standard limits( ＜ 3.5mg/d).ConclusionDrinking low-fluoride brick tea can prevent drinking brick tea type fluorosis,the preventive effect is especially more reliable with low fluoride brick tea (204.5 ± 10.2)mg/kg.

OBJECTIVETo design ABC damage variable and positioning system for acetabular fracture and explore the feasibility and clinical practical value of the system through the multi-center analysis of 1122 acetabular fractures.

METHODSAccording to acetabular three-column conception, and pelvic ring lesions damage direction caused by acetabular fracture domino effect and injury degree of proximal femur joint, it defined class A as any column acetabular fracture; class B as any two-column acetabular fracture; class C as front, dome and posterior mixture acetabular fracture. Lower case English letters a, m, p represented front, dome, posterior fracture, respectively. Acetabular damage variables: 1 was simple displaced fractures; 2 was comminuted fractures; 3 was compression fractures. Pelvic ring lesions damage variables: alpha was sacroiliac joints or sacroiliac fracture horizontal separation deflection; beta was sacroiliac joints or sacroiliac fracture vertical separation deflection; gamma was pubic symphysis separation/superior and inferior ramus of pubis fracture deflection; alpha beta gamma delta was compound floating damage. Proximal humerus joint damage variables: I was femoral head fracture; II was femoral neck fracture; II was intertrochanteric fractures of femur; IV was I to III compound fracture. The ABC damage variable positioning system for acetabular fracture was made up by the above-mentioned variables. The statistics from March 1997 to February 2010 showed 1122 cases acetabular fractures with 18 cases of double side acetabular fracture and 1140 cases of acetabular fractures. The pelvics anterior-posterior view, ilium and obturator oblique view, and 2/3D-CT materials were analyzed and researched.

RESULTSEach damage variables distribution situation in 1140 cases of acetabular fracture involved A in 237 cases (20.8%), B in 605 cases (53.1%), C in 298 cases (26.1%);front column fracture in 808 cases(70.9%), dome fracture in 507 cases (44.5%), posterior fracture in 1026 cases (90%). Acetabular variables: variabe 1 in 203 cases of simple displaced fracture (17.8%); variabe 2 in 516 cases of comminuted fracture(45.3%); variabe 3 in 421 cases of compression fracture (36.9%); 249 cases of pelvic ring lesions damage (21.8%), 75 cases femoral head fracture (6.6%); 18 cases of double side acetabular fracture and relative pelvic ring and proximal humerus joint variables (1.58%). Key part and curative effect elements of 1140 cases acetabular fracture: 507 cases of dome or posterior acetabular fracture (44.5%); 421 cases of compression fracture (36.9%); 249 cases of pelvic ring variables (21.8%); 75 cases of proximal humerus joint variables (6.6%); 486 cases of simple Aa/pl/2,Bapl/2 acetabular fracture (42.6% ).

CONCLUSIONCompression fracture, especially defected compression fracture, takes important part in acetabular damage variables, and also presents that acetabular fracture with pelvic ring and proximal femoral damage variables are not rare at all. The relationship of the acetabular fracture damage variables, and its percentage shows the key points and elements in clinical treatment: weight-bearing to dome accounts for 44.5%; compression to defects account for 36.9%, pelvic ring to float accounts for 21.8%; dome fracture to double side fracture account for 6.6%. The system has significant guiding effects on clinic in terms of evaluation of injury severity, anatomic localization, difficulty index, alternative strategy, operative approach, effect of treatment,and prognosis. And the most important thing is that the system creates the comparison of damage variables in same type of fracture and the communication of homo-language and explores a new method.

Acetabulum ; injuries ; Adolescent ; Adult ; Aged ; Child ; Female ; Fractures, Bone ; classification ; diagnostic imaging ; Humans ; Male ; Medical Informatics ; methods ; Middle Aged ; Tomography, X-Ray Computed ; Young Adult

Objective To investigate the dynamics and development trends of drinking water type of endemic fluorosis after water improvement in Xinbaerhuyouqi of Hulunbeir city, Inner Mongolia and to provide a scientific evidence for the development of countermeasures. Methods We mainly selected Adunchulusumu and Kerlunsumu in Xinbaerhuyouqi of Hulunbeir city as the two monitoring points after water improvement in 2000 -2009. Of these, 1 sample of centralized water supply source water and 3 samples of tap water and 5 samples of noncentralized water supply source water according to water well locations of east, west, south, north and center were collected and the levels of water fluoride were tested; the prevalence of dental fluorosis of school children aged 8 to 12 were examined; from 2002 onwards, the urine samples of 30 children aged 8 to 12(five age groups, six urine samples for each age group) were collected, and all urine samples were collected in the case of less than 30, and urine fluoride was tested. Dental fluorosis was diagnosed using Dean method; water fluoride was tested using fluoride ion selective electrode(WS/T 106-1999); urinary fluoride was tested by determination of fluoride in urine using ion-selective electrode(WS/T 89-1996). Results In 2000 - 2009, the mean levels of fluorine in drinking water in Adunchulusumu and Kerlunsumu were 1.79 - 4.35 mg/L and 1.38 - 3.18 mg/L, respectively; the detection rate of dental fluorosis of children aged 8 to 12 were 45.24％(19/42) - 89.78％(123/137) and 40.00％ (28/70) - 74.47％ (70/94), respectively; the median urinary fluoride of them were 2.30 - 4.15 mg/L and 2.73 - 4.55 mg/L, respectively. ConclusionsThe detection rate of children's dental fluorosis remains high in Xinbaerhuyouqi during the past 10 years after changing water. The endemic fluorosis remains a serious disease. Effective prevention and control measures must be taken to control the occurrence of fluorosis in the future.

Kv4.3 channel is present in many mammalian tissues, predominantly in the heart and central nervous system. Its currents are transient, characterized by rapid activation and inactivation. In the hearts of most mammals, it is responsible for repolarization of the action potential of ventricular myocytes and is important in the regulation of the heart rate. Because of its central role in this important physiological process, Kv4.3 channel is a promising target for anti-arrhythmic drug development. Jingzhaotoxin-V (JZTX-V) is a novel peptide neurotoxin isolated from the venom of the spider Chilobrachys jingzhao. Whole-cell patch clamp recording showed that it partly blocked the transient outward potassium channels in dorsal root ganglion neurons of adult rats with an IC(50) value of 52.3 nmol/L. To investigate the effect of JZTX-V on Kv4.3 channel, JZTX-V was synthesized using the solid-phase chemical synthesis and separated by reverse phase high performance liquid chromatography (HPLC). The purity was tested by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MOLDI-TOF mass spectrometry). Two-electrode voltage-clamp technique was used to characterize the action of JZTX-V on Kv4.3 channels expressed in Xenopus laevis oocytes. As a result, JZTX-V displayed fast kinetics of inhibition and recovery from inactivation. Furthermore, it could inhibit Kv4.3 channel current in a time- and concentration-dependent manner with an IC(50) value of 425.1 nmol/L. The application of JZTX-V affected the activation and inactivation characteristics of Kv4.3 channel and caused a shift of the current-voltage relationship curve and the steady-state inactivation curve to depolarizing direction by approximately 29 mV and 10 mV, respectively. So we deduced that JZTX-V is a gating modifier toxin of Kv4.3 channel. Present findings should be helpful to develop JZTX-V into a molecular probe and drug candidate targeting to Kv4.3 channel in the myocardium.
Animals ; Ganglia, Spinal ; cytology ; Neurons ; drug effects ; Neurotoxins ; pharmacology ; Oocytes ; Patch-Clamp Techniques ; Peptides ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Rats ; Shal Potassium Channels ; metabolism ; Spider Venoms ; pharmacology ; Xenopus laevis