RESUMO
BACKGROUND: Optimal CPAP strategy to prevent CPAP failure defined as need for endotracheal intubation is unknown. OBJECTIVE: To evaluate the risk of CPAP failure in infants treated with high vs low CPAP strategy while receiving aerosolized calfactant in the AERO-02 clinical trial and AERO-03 expanded access program. METHODS: Infants born between 29 0/7 to 36 6/7 weeks were included. Comparisons were made between low and high CPAP groups (Low, 4-7 cm H2O; High, 8-10 cm H2O). RESULTS: CPAP failure and pneumothorax were not different between the groups. Odds of CPAP failure were not different after adjustment for baseline characteristics (OR = 0.61; 95% CI: 0.29, 1.24). CONCLUSION: We found no difference in CPAP failure among infants who received aerosolized calfactant that were treated with high vs low CPAP strategy. Efficacy of high CPAP strategy with aerosolized surfactant treatment needs to be evaluated in future studies.
RESUMO
Intolerance of uncertainty is a transdiagnostic risk factor for fear-related disorders and is associated with higher levels of anxiety in children and adolescents. It is unclear how uncertainty relates to development of psychopathology in children who have experienced trauma in early life. The present study used a fear-potentiated startle paradigm in children to examine associations between uncertainty (assessed as unawareness of a change in reinforcement during fear extinction) and symptoms of anxiety and posttraumatic stress disorder (PTSD), as well as startle potentiation to threat and safety cues. Results showed that unaware children had strong positive associations between trauma exposure and PTSD symptoms, whereas aware children did not. Uncertainty interacted with anxiety in that children who were both unaware and had higher anxiety displayed higher fear-potentiated startle to safety cues and did not show discrimination between threat and safety during fear conditioning. These results suggest that anxious children who persist in associating a threat cue with an aversive event during extinction, after repeated presentations of the no longer reinforced conditioned stimulus, may express psychophysiological phenotypes related to PTSD.
Assuntos
Transtornos de Estresse Pós-Traumáticos , Adolescente , Criança , Extinção Psicológica/fisiologia , Medo/fisiologia , Humanos , Transtornos Fóbicos , Reflexo de Sobressalto/fisiologia , IncertezaRESUMO
BACKGROUND: Histone deacetylases (HDACs) are crucial components of the oestrogen receptor (ER) transcriptional complex. Preclinically, HDAC inhibitors can reverse tamoxifen/aromatase inhibitor resistance in hormone receptor-positive breast cancer. This concept was examined in a phase II combination trial with correlative end points. METHODS: Patients with ER-positive metastatic breast cancer progressing on endocrine therapy were treated with 400 mg of vorinostat daily for 3 of 4 weeks and 20 mg tamoxifen daily, continuously. Histone acetylation and HDAC2 expression in peripheral blood mononuclear cells were also evaluated. RESULTS: In all, 43 patients (median age 56 years (31-71)) were treated, 25 (58%) received prior adjuvant tamoxifen, 29 (67%) failed one prior chemotherapy regimen, 42 (98%) progressed after one, and 23 (54%) after two aromatase inhibitors. The objective response rate by Response Evaluation Criteria in Solid Tumours criteria was 19% and the clinical benefit rate (response or stable disease >24 weeks) was 40%. The median response duration was 10.3 months (confidence interval: 8.1-12.4). Histone hyperacetylation and higher baseline HDAC2 levels correlated with response. CONCLUSION: The combination of vorinostat and tamoxifen is well tolerated and exhibits encouraging activity in reversing hormone resistance. Correlative studies suggest that HDAC2 expression is a predictive marker and histone hyperacetylation is a useful pharmacodynamic marker for the efficacy of this combination.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Antagonistas de Estrogênios/administração & dosagem , Inibidores de Histona Desacetilases/uso terapêutico , Ácidos Hidroxâmicos/uso terapêutico , Tamoxifeno/uso terapêutico , Acetilação , Adulto , Idoso , Neoplasias da Mama/mortalidade , Feminino , Histona Desacetilase 2/análise , Inibidores de Histona Desacetilases/administração & dosagem , Inibidores de Histona Desacetilases/efeitos adversos , Histonas/metabolismo , Humanos , Ácidos Hidroxâmicos/administração & dosagem , Ácidos Hidroxâmicos/efeitos adversos , Pessoa de Meia-Idade , Tamoxifeno/administração & dosagem , Tamoxifeno/efeitos adversos , VorinostatRESUMO
BACKGROUND: Histone deacetylase inhibitors (HDACi) can sensitise cancer cells to topoisomerase inhibitors by increasing their access and binding to DNA. METHODS: This phase I trial was designed to determine the toxicity profile, tolerability, and recommended phase II dose of escalating doses of the HDACi vorinostat, with weekly doxorubicin. RESULTS: In total, 32 patients were treated; vorinostat was dosed at 400, 600, 800, or 1000 mg day(-1) on days 1-3, followed by doxorubicin (20 mg m(-2)) on day 3 for 3 of 4 weeks. Maximal tolerated dose was determined to be 800 mg day(-1) of vorinostat. Dose-limiting toxicities were grade 3 nausea/vomiting (two out of six) and fatigue (one out of six) at 1000 mg day(-1). Non-dose-limiting grade 3/4 toxicities included haematological toxicity and venous thromboembolism. Antitumor activity in 24 evaluable patients included two partial responses (breast and prostate cancer). Two patients with melanoma had stable disease for > or =8 months. Histone hyperacetylation changes in peripheral blood mononuclear and tumour cells were comparable. Histone hyperacetylation seemed to correlate with pre-treatment HDAC2 expression. CONCLUSION: These findings suggest that vorinostat can be combined with weekly doxorubicin in this schedule at a dose of 800 mg day(-1). The HDAC2 expression may be a marker predictive of HDAC inhibition. Antitumor activity of this regimen in breast cancer, prostate cancer, and melanoma seems interesting.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Inibidores de Histona Desacetilases , Neoplasias/tratamento farmacológico , Acetilação , Adulto , Idoso , Idoso de 80 Anos ou mais , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Feminino , Coração/efeitos dos fármacos , Histona Desacetilases/análise , Histonas/metabolismo , Humanos , Ácidos Hidroxâmicos/administração & dosagem , Ácidos Hidroxâmicos/efeitos adversos , Masculino , Pessoa de Meia-Idade , VorinostatRESUMO
Constitutive activation of signal transducer and activator of transcription (STAT) proteins has been detected in a wide variety of human primary tumor specimens and tumor cell lines including blood malignancies, head and neck cancer, and breast cancer. We have previously demonstrated a high frequency of Stat3 DNA-binding activity that is constitutively-induced by an unknown mechanism in human breast cancer cell lines possessing elevated EGF receptor (EGF-R) and c-Src kinase activities. Using tyrosine kinase selective inhibitors, we show here that Src and JAK family tyrosine kinases cooperate to mediate constitutive Stat3 activation in the absence of EGF stimulation in model human breast cancer cell lines. Inhibition of Src or JAKs results in dose-dependent suppression of Stat3 DNA-binding activity, which is accompanied by growth inhibition and induction of programmed cell death. In addition, transfection of a dominant-negative form of Stat3 leads to growth inhibition involving apoptosis of breast cancer cells. These results indicate that the biological effects of the Src and JAK tyrosine kinase inhibitors are at least partially mediated by blocking Stat3 signaling. While EGF-R kinase activity is not required for constitutive Stat3 activation in breast cancer cells, EGF stimulation further increases STAT DNA-binding activity, consistent with an important role for EGF-R in STAT signaling and malignant progression. Analysis of primary breast tumor specimens from patients with advanced disease revealed that the majority exhibit elevated STAT DNA-binding activity compared to adjacent non-tumor tissues. Our findings, taken together, suggest that tyrosine kinases transduce signals through Stat3 protein that contribute to the growth and survival of human breast cancer cells in culture and potentially in vivo.
Assuntos
Neoplasias da Mama/patologia , Proteínas de Ligação a DNA/fisiologia , Proteínas de Drosophila , Proteínas Tirosina Quinases/fisiologia , Transativadores/fisiologia , Quinases da Família src/fisiologia , Animais , Apoptose/efeitos dos fármacos , Neoplasias da Mama/enzimologia , Neoplasias da Mama/metabolismo , Ciclo Celular/efeitos dos fármacos , Divisão Celular/fisiologia , DNA de Neoplasias/metabolismo , Proteínas de Ligação a DNA/metabolismo , Inibidores Enzimáticos/farmacologia , Receptores ErbB/biossíntese , Receptores ErbB/fisiologia , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Fibroblastos/fisiologia , Humanos , Proteínas de Insetos , Janus Quinase 1 , Camundongos , Fosforilação/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Piridonas/farmacologia , Pirimidinas/farmacologia , Fator de Transcrição STAT3 , Transdução de Sinais/fisiologia , Transativadores/metabolismo , Células Tumorais Cultivadas , Tirfostinas/farmacologia , Quinases da Família src/antagonistas & inibidores , Quinases da Família src/metabolismoRESUMO
OBJECTIVE: To compare neonatal red blood cell (RBC) transfusion rates in four large Intermountain Healthcare NICUs, all of which adhere to the same RBC transfusion guidelines. STUDY DESIGN: This retrospective analysis was part of a transfusion-management quality-improvement project. De-identified data included RBC transfusions, clinical and laboratory findings, the anemia-prevention strategies in place in each NICU, and specific costs and outcomes. RESULT: Of 2389 NICU RBC transfusions given during the 4-year period studied, 98.9 ± 2.1% (mean ± S.D.) were compliant with our transfusion guidelines, with no difference in compliance between any of the four NICUs. However, RBC transfusion rates varied widely between the four, with averages ranging from 4.6 transfusions/1000 NICU days to 21.7/1000 NICU days (P < 0.00001). Gestational age-adjusted transfusion rates were correspondingly discordant (P < 0.00001). The lower-transfusing NICUs had written anemia-preventing guidelines, such as umbilical cord milking at very low birth weight delivery, use of cord blood for admission laboratory studies, and darbepoetin dosing for selected neonates. Rates of Bell stage ⩾ 2 necrotizing enterocolitis and grade ⩾ 3 intraventricular hemorrhage were lowest in the two lower-transfusing NICUs (P < 0.0002 and P < 0.0016). Average pharmacy costs for darbepoetin were $84/dose, with an average pharmacy cost of $269 per transfusion averted. With a cost of $900/RBC transfusion, the anemia-preventing strategies resulted in an estimated cost savings to Intermountain Healthcare of about $6970 per 1000 NICU days, or about $282,300 annually. CONCLUSION: Using transfusion guidelines has been shown previously to reduce practice variability, lower transfusion rates and diminish transfusion costs. Based on our present findings, we maintain that even when transfusion guidelines are in place and adhered to rigorously, RBC transfusion rates are reduced further if anemia-preventing strategies are also in place.
Assuntos
Anemia/terapia , Transfusão de Eritrócitos , Idade Gestacional , Fidelidade a Diretrizes , Doenças do Prematuro/terapia , Padrões de Prática Médica , Anemia/diagnóstico , Anemia/etiologia , Hemorragia Cerebral/complicações , Redução de Custos/métodos , Enterocolite Necrosante/complicações , Transfusão de Eritrócitos/economia , Transfusão de Eritrócitos/métodos , Transfusão de Eritrócitos/estatística & dados numéricos , Feminino , Fidelidade a Diretrizes/normas , Fidelidade a Diretrizes/estatística & dados numéricos , Humanos , Recém-Nascido , Doenças do Prematuro/diagnóstico , Doenças do Prematuro/etiologia , Unidades de Terapia Intensiva Neonatal/estatística & dados numéricos , Terapia Intensiva Neonatal/métodos , Terapia Intensiva Neonatal/normas , Masculino , Guias de Prática Clínica como Assunto , Padrões de Prática Médica/normas , Padrões de Prática Médica/estatística & dados numéricos , Melhoria de Qualidade , Estudos Retrospectivos , Estados UnidosRESUMO
Bone mineral content was determined by photon absorptiometry, adapted for use in neonates, in 23 small-for-gestational-age (SGA) infants of 31 to 42 weeks of gestational age, for 12 weeks. At birth, term SGA infants had lower bone mineral content than term appropriate-for-gestational-age (AGA) infants; postnatal increase in bone mineral content was slow and lagged significantly behind that of term AGA infants. Preterm SGA infants had bone mineral content that was similar to that of preterm AGA infants at birth; postnatal bone mineral content was similar to that of preterm AGA infants, but was decreased compared with the expected intrauterine bone mineral content. Serum 25-hydroxyvitamin D concentrations and parathyroid hormone levels were the same for SGA and AGA infants. Serum 25-hydroxyvitamin D concentrations decreased slightly with postnatal age and remained within normal limits. Serum parathyroid hormone concentrations decreased in both SGA and AGA infants and reached undetectable levels at 10 to 12 weeks of age.
Assuntos
Osso e Ossos/análise , Ergocalciferóis/análogos & derivados , Recém-Nascido Pequeno para a Idade Gestacional , Minerais/análise , Hormônio Paratireóideo/sangue , 25-Hidroxivitamina D 2 , Cálcio da Dieta/administração & dosagem , Ergocalciferóis/sangue , Feminino , Crescimento , Humanos , Lactente , Alimentos Infantis , Recém-Nascido , Masculino , Vitamina D/uso terapêuticoRESUMO
OBJECTIVE: To compare the hospital course and clinical outcome of preterm infants with respiratory distress syndrome treated with surfactant and managed with high-frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CV) as their primary mode of ventilator support. DESIGN: A prospective randomized clinical trial. SETTING: Three community-based level III neonatal intensive care units. SUBJECTS: A total of 125 neonates who were 35 weeks or less estimated gestation requiring intubation and assisted ventilation for respiratory distress syndrome with arterial to alveolar oxygen ratio less than .50. INTERVENTIONS: Patients were randomized to continue CV (61 patients) or be changed to HFOV (64 patients) after exogenous surfactant administration (100 mg/kg). HFOV was used in a strategy to promote lung recruitment and maintain lung volume. Protocol respiratory care guidelines were followed; otherwise routine care was provided by each neonatal intensive care unit. MEASUREMENTS AND MAIN RESULTS: No differences were noted in demographic features between the two study groups. The study population birth weight was 1.51 +/- .47 kg (mean +/- SD), gestational age was 30.9 +/- 2.5 weeks, and study entry age was 2 to 3 hours. Patients randomized to HFOV demonstrated the following significant findings compared with CV-treated patients: vasopressor support was less intensive; surfactant redosing was not as frequent; oxygenation improved more rapidly and remained higher during the first 7 days; fewer infants required prolonged supplemental oxygen or ventilator support; treatment failure was reduced; more patients survived without chronic lung disease at 30 days; need for continuous supplemental oxygen at discharge was less; frequency of necrotizing enterocolitis illness was lower; there were fewer abnormal hearing tests; and hospital costs were decreased. No differences were seen between the two study groups in the frequency or severity of patent ductus arteriosus, air leak, retinopathy of prematurity, or intraventricular hemorrhage. Length of hospital stay and survival to discharge were similar for HFOV- and CV-treated infants. CONCLUSIONS: When used early with a lung recruitment strategy, HFOV after surfactant replacement resulted in clinical outcomes consistent with a reduction in both acute and chronic lung injury. Benefit was evident for preterm infants both less than or equal to 1 kg and more than 1 kg. In addition, early HFOV treatment may have had a more global effect on patient health throughout the hospitalization, resulting in reduced morbidity and decreased health care cost.
Assuntos
Ventilação de Alta Frequência , Recém-Nascido Prematuro , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia , Tensoativos/uso terapêutico , Falha de Equipamento , Feminino , Ventilação de Alta Frequência/instrumentação , Hospitalização/economia , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Avaliação de Resultados em Cuidados de Saúde , Troca Gasosa Pulmonar , Respiração Artificial , Síndrome do Desconforto Respiratório do Recém-Nascido/economia , Retinopatia da Prematuridade/etiologia , Falha de Tratamento , UtahRESUMO
Germline mutations in the PTEN gene have recently been identified in some individuals with Cowden disease (CD), Lhermitte-Duclos disease (LDD), and Bannayan-Zonana syndrome. We report on a patient with CD and LDD in whom a unique de novo germline missense mutation is present in the PTEN gene. Direct sequence analysis detected a transitional change (T-->C) at nucleotide 335, resulting in substitution of the amino acid proline for leucine. The mutation is in exon 5, which has been proposed as a "hot-spot" for germline mutations. Comparison of this patient's clinical course with the previously reported cases of CD and LDD shows more extensive and more severe clinical findings than reported previously. Findings in this patient contribute to the current understanding of germline PTEN mutations and clinical outcome.
Assuntos
Neoplasias Cerebelares/genética , Ganglioneuroma/genética , Síndrome do Hamartoma Múltiplo/genética , Monoéster Fosfórico Hidrolases/genética , Proteínas Supressoras de Tumor , Adulto , Feminino , Mutação em Linhagem Germinativa , Humanos , Mutação de Sentido Incorreto , PTEN Fosfo-Hidrolase , Mutação Puntual , Dermatopatias/genética , SíndromeRESUMO
Age is the most important risk factor for the development of breast cancer. The risk of breast cancer continues to increase in American women until the age of 80 years. A family history of breast cancer helps identify those who possibly have the highest risk of developing breast cancer; however, most women who develop breast cancer do not have a first-degree relative with a history of breast cancer. Currently, the Gail model is a commonly used model to identify risk, and this model has now been validated in several populations of women undergoing screening for breast cancer. The first large-scale breast cancer prevention trial investigating the preventive effects of tamoxifen has demonstrated a decrease in the development of breast cancer by almost 50% in the women in the tamoxifen treatment arm as compared with those receiving placebo. The NSABP P-1 trial was the largest of the three tamoxifen breast cancer prevention trials and had the greatest power to detect a difference between the two treatment groups in breast cancer events. This trial also included the largest percentage of postmenopausal women. It is unclear why the Italian and Royal Marsden Hospital trials had negative results regarding the preventive effects of tamoxifen. These two trials were strikingly different from the NSABP P-1 trial, however, and they included a different population of women. The issues surrounding the use of HRT for treatment of hot flashes in the Italian and Royal Marsden Hospital trials adds to the controversy concerning the negative results of these trials. The new SERM, raloxifene, has shown promise in preliminary studies as a preventive agent for breast cancer. The STAR trial will open soon and will evaluate the efficacy of raloxifene in preventing breast cancer in a prospective fashion, comparing its efficacy with tamoxifen treatment. Other endpoints will evaluate side effects such as menopausal symptoms, endometrial cancer, thromboembolic events, and benefits regarding serum lipids and incidence of osteoporotic bone fractures. The development of SERMs results from an understanding of novel mechanisms of ER modulation and allows targeting for favorable effects in specific tissues. The challenge is to develop an ideal SERM that is effective in preventing breast cancer and does not increase the risk of endometrial cancer, while providing beneficial estrogenic effects on serum lipids and bone mineral density changes. Estrogen receptor-mediated intracellular processes are complex. There are at least two different types of estrogen receptors. The alpha receptors predominate in the breast and uterus, and the beta receptors predominate in the bone and blood vessels. Many proteins also interact with these receptors as co-activators or co-repressors. Transcription-activating factors modulate the effects of estrogen on its target genes. Future prevention strategies may use a combined targeted approach to inhibit ER-mediated cancer progression pathways. The retinoids are under investigation in prevention studies for a multitude of cancers, because they have been shown to inhibit cellular proliferation and to induce cellular differentiation. The retinoid 4HPR was selected for use in breast cancer prevention studies because of its low toxicity profile and prevention efficacy in preclinical studies. It is now being used in combination with tamoxifin in a phase II breast cancer prevention trial. Multiple surrogate endpoint biomarkers are being measured before and after treatment, including measurement of serum IGF-I levels. Future directions in breast cancer prevention include the development of more potent hormonal therapies that completely inhibit ER-mediated cancer progression and, ultimately, multitargeted therapies involving agents that work synergistically.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/prevenção & controle , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Neoplasias da Mama/fisiopatologia , Feminino , Humanos , Cloridrato de Raloxifeno/uso terapêutico , Retinoides/uso terapêutico , Fatores de Risco , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Tamoxifeno/uso terapêuticoRESUMO
BACKGROUND: Breast cancer represents the leading form of invasive cancer among American women, killing nearly 50,000 annually. Several prognostic factors that are associated with survival include age, race, menopausal status, and the stage of disease at presentation. METHODS: Patient characteristics were collected based on a systematic chart audit of demographic features and medical, family, and social histories. We studied the survival of 220 patients with recurrent disease out of 1,429 consecutive patients with breast cancer seen over a 15-year period. RESULTS: Patients with a disease-free interval following diagnosis of less than 24 months were more frequently premenopausal and hormone receptor-negative than those with a disease-free interval of 24 months or greater. Patients with early recurrence had a shorter survival than patients with late recurrence. Menopausal status, nodal involvement, receptor status, and the site of recurrent disease were independent predictors of survival following recurrence. CONCLUSIONS: Premenopausal women with early recurrence of breast cancer experience a significantly shorter survival than those with late recurrence, even after adjustment for hormone receptor status and site of recurrence. This effect was not seen in postmenopausal women.
RESUMO
Lethal doses in mice are reported for venoms of six species of snakes collected in the Coral Sea. Three have not previously been evaluated. Venom of Aipysurus duboisii has extremely high lethality exceeded by only one snake species. Secretion from Emydocephalus annulatus is essentially non-toxic.
Assuntos
Venenos Elapídicos/toxicidade , Animais , Dose Letal Mediana , Camundongos , Camundongos Endogâmicos ICRRESUMO
Venom samples from western diamondback rattlesnakes (Crotalus atrox) from 13 localities in the United States were tested for i.v. and s.c. lethality for mice, protease activity, hemorrhagic activity, and the presence of Mojave toxin. Electrophoresis on polyacrylamide gel was used to compare protein composition. The neutralizing effect of two commercial antivenoms was evaluated against selected samples of venom. Venom of young snakes from north Texas was compared with that of adults from the same locality. Venom samples from the southwest portion of the range showed highest lethality, those from the northeast portion lowest. This trend was reversed with respect to protease activity. Hemorrhagic activity showed little geographic variation, but northern samples tended to be slightly higher. Differences in venom protein composition were evident between snakes from the eastern and western portions of the range. Mojave toxin in small to trace amounts was detected in two Arizona venom samples and one from west Texas. Antivenoms were relatively ineffective in neutralizing lethality. Venom of young snakes from north Texas was much more lethal by s.c. injection than that of adult snakes from any part of the range, but very low in protease activity. Hemorrhagic activity was about equal to that of adult snakes from the same region. Fifteen months later, lethality had declined almost five-fold, and protease activity had approached adult levels. There was a distinct change in protein composition. Mojave toxin was not detected in venoms of the young snakes.
Assuntos
Venenos de Crotalídeos/toxicidade , Animais , Antivenenos/farmacologia , Autorradiografia , Venenos de Crotalídeos/análise , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Geografia , Hemorragia/induzido quimicamente , Masculino , Camundongos , Peptídeo Hidrolases/análise , Ratos , Especificidade da Espécie , Estados UnidosRESUMO
Information on yield, lethality, and protease activity is given for venoms of Crotalus exul, C. p. pricei, C. pusillus, C. w. willardi and Sistrurus ravus. Lethal toxicity of C. tigris venom (LD50 i.v. 0.056 mg/kg; s.c. 0.21 mg/kg) is the highest known for any rattlesnake venom. The lethal potency of C. pricei venom is high by i.v. but not by s.c. injection. Both these venoms lack protease activity. C. pusillus venom is lowest in lethality.
Assuntos
Venenos de Crotalídeos/análise , Peptídeo Hidrolases/análise , Animais , Venenos de Crotalídeos/toxicidade , Dose Letal Mediana , CamundongosRESUMO
Lethality determinations are reported for Vipera bornmulleri and V. latifii. V. latifii venom is significantly more toxic than V. bornmulleri by the i.v. route; by the i.p. and s.c. routes there is little difference between the species. Immunoelectrophoretic profiles indicate close antigenic relationship between venoms of these species and V. palaestinae and Bitis spp.; a more remote relationship with V. russelli and Echis carinatus. Protease activity of V. latifii venom is stronger than that of V. bornmulleri.
Assuntos
Venenos de Víboras/toxicidade , Animais , Imunoeletroforese , Dose Letal Mediana , Masculino , Camundongos , Camundongos Endogâmicos ICR , Venenos de Víboras/análiseRESUMO
Proteolytic, hemorrhagic and hemolytic activities were tested on 47 different venoms from the Crotalidae, Viperidae, Elapidae, and Hydrophiidae families. Antihemorrhagic activity of crude opossum (Didelphis virginiana) and woodrat (Neotoma micropus) serum was tested against the venoms that presented hemorrhagic activity. All venoms showed proteolytic activity when non-specific substrates such as hide powder and collagen were used. Members of the Crotalidae family had the highest hide powder, chymotrypsin-like and hemorrhagic activity. However, members of the Elapidae family had the highest collagen activity. Hemolytic activity was present in 85% of the snake venoms tested. The crude opossum and woodrat serum neutralized the hemorrhagic activity of all the hemorrhagic venoms. Of particular interest is the poor correlation between the venom activities measured here and the phylogenetic position of the snake that possess them. This is particularly true at the genus and species level. Differences in activities were found among individuals of the same genus. The significance of these differences among venoms of closely related snakes is unknown. They do not seem to be adaptive, however little is known of the physiology and habits of most venomous snakes.
Assuntos
Hemólise/efeitos dos fármacos , Hemorragia/induzido quimicamente , Peptídeo Hidrolases/farmacologia , Venenos de Serpentes/farmacologia , Animais , Coelhos , Serpentes/classificaçãoRESUMO
A toxin analogous to Mojave toxin or protein K' was isolated from venom of the Mojave rattlesnake (Crotalus s. scutulatus) by anion exchange and gel permeation chromatography. This toxin has an apparent native molecular weight of 20,000-22,000, a subunit molecular weight of 14,000 and a pI of 4.9-5.0. The i.p. LD50 is 0.094 mg/kg for mice. A wide variety of ophidian venoms (crotaline, viperine, elapid, hydrophid and colubrid) were examined for the presence of this toxin using Ouchterlony, immunoelectrophoresis, ELISA and Western transfer. High concentrations were found in 4 of 6 C. scutulatus venom samples, 2 of 3 C. durissus samples and samples from C. viridis concolor and C. tigris. A moderate concentration was found in 1 of 3 C. durissus samples and low to trace concentrations in 1 C. durissus sample, 1 C. scutulatus sample, 2 of 12 C. atrox samples and a Trimeresurus flavoviridis sample, the latter being the only instance of detection of the toxin in a snake other than a rattlesnake. The toxin appears in at least two phylogenetic lines of rattlesnakes, and its geographic distribution in North American rattlesnake species resembles a mosaic.
Assuntos
Venenos de Crotalídeos/análise , Neurotoxinas/análise , Animais , Especificidade de Anticorpos , Antivenenos/análise , Cromatografia em Gel , Cromatografia por Troca Iônica , Venenos de Crotalídeos/toxicidade , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Imunodifusão , Imunoeletroforese , Masculino , Camundongos , Camundongos Endogâmicos ICR , Neurotoxinas/toxicidade , Especificidade da EspécieRESUMO
Previous studies have analyzed abilities of snake venoms to preferentially kill certain animal cells. Some studies have examined selective cytotoxic effects of snake venoms on B and T lymphocytes, but few studies have determined abilities of snake venoms to interact with B and T cells at distinct stages of cellular development. Thus, this study has analyzed susceptibilities of immature and mature BALB/cAn splenic B cells and T cells to cytotoxic effects of crude venoms of snakes belonging to the families of Crotalidae, Elapidae, and Viperidae. Both mitogen-stimulated and unstimulated BALB/cAn Ig- splenic T cells are sensitive to cytotoxic effects of snake venoms whereas mitogen-stimulated but not unstimulated Ig+ splenic B lymphocytes are sensitive to snake venoms. We also find that BALB/cAn myelomas but not B cell lymphomas are sensitive to cytotoxic effects of snake venoms. In addition, plaque forming cells making IgG1 subclass in BALB/cAn mitogen-stimulated spleens and in myelomas are preferentially killed by venom of pit viper Bothrops asper. Thus, the cytotoxic effects of crude snake venoms can distinguish BALB/cAn PFC making IgG1 subclass from other B and T cells.
Assuntos
Linfócitos B/efeitos dos fármacos , Venenos de Serpentes/toxicidade , Linfócitos T/efeitos dos fármacos , Animais , Células Cultivadas , Feminino , Isotipos de Imunoglobulinas , Camundongos , Camundongos Endogâmicos BALB C , Baço/efeitos dos fármacos , Células Tumorais Cultivadas/efeitos dos fármacos , Ensaio de Placa ViralRESUMO
We report two neonates in whom placement of a chest tube for pneumothorax was followed by hemorrhage, shock, and subsequent death. An autopsy of one of the patients led us to the conclusion that bleeding had occurred from lung perforation. The intercostal artery had been clearly severed and may have contributed to the hemorrhage. We discuss pathogenesis, diagnosis, and offer suggestions for proper placement of the tube.