RESUMO
Estuarine crocodiles, Crocodylus porosus, inhabit freshwater, estuarine and marine environments. Despite being known to undertake extensive movements throughout and between hypo-osmotic and hyperosmotic environments, little is known about the role of the cloaca in coping with changes in salinity. We report here that, in addition to the well-documented functional plasticity of the lingual salt glands, the middle of the three cloacal segments (i.e. the urodaeum) responds to increased ambient salinity to enhance solute-coupled water absorption. This post-renal modification of urine serves to conserve water when exposed to hyperosmotic environments and, in conjunction with lingual salt gland secretions, enables C. porosus to maintain salt and water balance and thereby thrive in hyperosmotic environments. Isolated epithelia from the urodaeum of 70% seawater-acclimated C. porosus had a strongly enhanced short-circuit current (an indicator of active ion transport) compared with freshwater-acclimated crocodiles. This enhanced active ion absorption was driven by increased Na+/K+-ATPase activity, and possibly enhanced proton pump activity, and was facilitated by the apical epithelial Na+ channel (ENaC) and/or the apical Na+/H+ exchanger (NHE2), both of which are expressed in the urodaeum. NHE3 was expressed at very low levels in the urodaeum and probably does not contribute to solute-coupled water absorption in this cloacal segment. As C. porosus does not appear to drink water of salinities above 18 ppt, observations of elevated short-circuit current in the rectum as well as a trend for increased NHE2 expression in the oesophagus, the anterior intestine and the rectum suggest that dietary salt intake may stimulate salt and possibly water absorption by the gastrointestinal tract of C. porosus living in hyperosmotic environments.
Assuntos
Jacarés e Crocodilos/fisiologia , Cloaca/metabolismo , Reto/metabolismo , Salinidade , Aclimatação/fisiologia , Jacarés e Crocodilos/metabolismo , Animais , Canais Epiteliais de Sódio/genética , Canais Epiteliais de Sódio/metabolismo , Transporte de Íons/fisiologia , Masculino , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismo , Urina/químicaRESUMO
BACKGROUND: The purpose of this study was to assess the concordance of real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) detection of ESR1, PGR, ERBB2, and MKi67 messenger RNA (mRNA) in breast cancer tissues with central immunohistochemistry (IHC) in women treated within the prospective, randomized Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 6. PATIENTS AND METHODS: We evaluated ESR1, PGR, ERBB2, and MKi67 mRNA expression by Xpert® Breast Cancer STRAT4 (enables cartridge-based RT-qPCR detection of mRNA in formalin-fixed paraffin-embedded tissues) and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki67 protein expression by IHC [in situ hybridization (ISH) for HER2 IHC 2+] in 1115 surgical formalin-fixed paraffin-embedded specimens from patients of ABCSG Trial 6. Overall percent agreement (concordance), positive percent agreement (sensitivity), and negative percent agreement (specificity) between STRAT4 and IHC were determined for each marker. The primary objective of the study was concordance between STRAT4 mRNA measurements of ESR1, PGR, ERBB2, and MKi67 with central reference laboratory IHC (and ISH for HER2 IHC 2+ cases). Time to distant recurrence was analyzed by Cox models. RESULTS: All performance targets for ER, PR, and Ki67 were met. For HER2, the negative percent agreement target but not the positive percent agreement target was met. Concordance between STRAT4 and IHC was 98.9% for ER, 89.9% for PR, 98.2% for HER2, and 84.8% for Ki67 (excluding intermediate IHC 10%-20% staining). In univariable and multivariable Cox regression analyses, all four biomarkers tested by either STRAT4 RT-qPCR or by central IHC (ISH) had a comparable time to distant recurrence indicating similar prognostic value. CONCLUSIONS: With the exception of HER2, we demonstrate high concordance between centrally assessed IHC and mRNA measurements of ER, PR, and Ki67 as well as a high correlation of the two methods with clinical outcome. Thus, mRNA-based assessment by STRAT4 is a promising new tool for diagnostic and therapeutic decisions in breast cancer.
Assuntos
Neoplasias da Mama , Receptores de Progesterona , Biomarcadores Tumorais/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Receptor alfa de Estrogênio/genética , Feminino , Hormônios , Humanos , Antígeno Ki-67/genética , Recidiva Local de Neoplasia , Pós-Menopausa , Estudos Prospectivos , RNA Mensageiro/genética , Receptor ErbB-2 , Receptores de Progesterona/genéticaRESUMO
PURPOSE: Alveolar-capillary barrier dysfunction, characterized by alveolar protein leak and lung edema, is a common scenario following cardiopulmonary surgery and thoracic organ transplantation. Reactive oxygen species generated through lung ischemia and reperfusion (I/R) injury during surgery plays a crucial role. Niacin, also known as vitamin B3, has been demonstrated to possess antioxidative and anti-inflammatory capacity. In this study, we examine the pulmonary barrier function via capillary filtration coefficient (Kfc) following lung I/R injury with and without niacin treatment. METHODS: Studies were conducted on male Sprague-Dawley rats in 3 groups: sham-operated, lung I/R injury, and niacin-pretreated lung I/R injury group. Rats were subjected to isolated perfused lung preparation. Lung ischemia was established by continuous perfusion and stopping ventilation for 60 minutes, followed by 60 minutes of ventilation. We assessed the Kfc, lung water content, and protein concentration in the lung lavage; pulmonary oxidative stress and lung inflammation were assessed by leukocyte counts, tissue level of tumor nercrosis factor alpha (TNF-α), and tissue content of malondialdehyde (MDA), respectively. We also assessed the tissue protein level of sirtuin (silent mating type information regulation 2 homolog) 1 (SIRT1). RESULTS: Lungs subjected to I/R injury significantly increased Kfc, pulmonary oxidative stress, lung water content, and lavage leukocyte count and protein concentration (P < .05). Rats treated with niacin of 100 mg/kg/day for 4 days increased lung SIRT1 (P < .05) and attenuated lung I/R injury-induced pulmonary oxidative stress and inflammation and also improved Kfc. CONCLUSIONS: Niacin pretreatment protects lungs against I/R injury-induced barrier function impairment through the activation of SIRT1 and reduced pulmonary oxidative stress and lung inflammation.
Assuntos
Transplante de Pulmão , Niacina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Traumatismo por Reperfusão/prevenção & controle , Sirtuína 1/metabolismo , Animais , Antioxidantes/farmacologia , Modelos Animais de Doenças , Sobrevivência de Enxerto/efeitos dos fármacos , Sobrevivência de Enxerto/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/patologiaRESUMO
Using isoelectric focusing, a fetal hemoglobin was found in the peripheral blood of C57BL/6 fetal mouse during the 14 to 20 days gestational period. In acid-urea polyacrylamide gel the pattern of this fetal hemoglobin was different from that of the adult hemoglobin. The mouse fetal hemoglobin was differentiated from the mouse adult hemoglobin by immunodiffusion reaction. It suggests that there is a transient fetal hemoglobin in the C57BL/6 mouse during gestational age.
Assuntos
Hemoglobina Fetal/metabolismo , Animais , Feminino , Feto , Idade Gestacional , Imunodifusão , Camundongos , Camundongos Endogâmicos C57BL , GravidezRESUMO
Multiple hemoglobins were found in the peripheral blood of hamsters when separated by analytical isoelectric focusing in polyacrylamide gel between pH 6.0 and pH 8.0. Five of these hemoglobins (I-V) were present in sufficient quantities for isolation by preparative isoelectric focusing and subsequent characterization. Cellulose acetate electrophoresis of the isolated hemoglobins resulted in producing as many as six different globin chains. The five hemoglobins were further characterized by their amino acid composition, N-terminal amino acid residue, and molecular weight.
Assuntos
Hemoglobinas , Aminoácidos/análise , Animais , Animais Recém-Nascidos , Cricetinae , Eletroforese em Acetato de Celulose , Hemoglobinas/isolamento & purificação , Focalização Isoelétrica , Mesocricetus , Peso MolecularRESUMO
Friend leukemia cells (GM86, clone 745) were induced to differentiate with dimethyl sulfoxide or butyric acid. The kinetics of induction were measured by cell growth, cell volume distributions, and [3H]thymidine incorporation. From the volume distributions, it was found that the rate of induction was both agent sensitive and concentration dependent. The changes in volume distributions occurred approximately 4 hr earlier with dimethyl sulfoxide induction relative to butyric acid induction. However, the changes with the butyric acid induction were more dependent on concentration. A decrease in labeling indices during the 12- to 20-hr time period was correlated to a decrease in mean cell volume and an increase in the proportion of G1 cells. After the 20-hr time period of induction, an increase in labeling indices and in the percentage of large cells was observed. The data suggest that a transient block of cells in G1 occurred between 12 to 20 hr, and that the early differentiation involved a volume decrease which was related to a redistribution of cell cycle stages. The study was also shown that the changes of cell volume are a rapid monitor to determine the early events of the differentiation process.
Assuntos
Células Cultivadas/citologia , Animais , Butiratos/farmacologia , Contagem de Células , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , DNA de Neoplasias/biossíntese , Dimetil Sulfóxido/farmacologia , Vírus da Leucemia Murina de Friend , Leucemia Experimental , CamundongosRESUMO
Four animal transplantable solid tumors, composed of varying morphologic architecture and intercellular specializations, were studied by light and electron microscopy. These tumors were dissociated into viable single cell populations using a combination of mechanical and enzymatic methods. The conditions necessary for optimal dissociation consisted of (a) preparation of the tumor to maximize the tissue surface area, (b) enzymatic digestion with continuous agitation and (c) additional agitation to release loosely attached cells. Other factors that influenced the dissociation were optimized and discussed.
Assuntos
Adenocarcinoma Papilar , Separação Celular/métodos , Melanoma , Neoplasias , Adenocarcinoma Papilar/patologia , Animais , Sobrevivência Celular , Feminino , Junções Intercelulares/ultraestrutura , Masculino , Glândulas Mamárias Animais , Melanoma/patologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Colagenase Microbiana , Transplante de Neoplasias , Neoplasias/patologia , TripsinaRESUMO
Meconium has been reported to be a more suitable specimen than maternal or neonatal urine for detecting fetal exposure to cocaine. In a study comparing various immunoassays with gas chromatography/mass spectrometry (GC/MS), several unexplained discrepancies among the assays were noted. Using methanol extracts of meconium samples, an immunoreactive spot that was more polar than benzoylecgonine was detected by thin-layer chromatography (TLC). An extract of this spot analyzed by GC/MS yielded a fragmentation pattern indicative of an aryl hydroxylated benzoylecgonine. Standards of m-hydroxybenzoylecgonine, o-hydroxybenzoylecgonine, and p-hydroxybenzoylecgonine were synthesized; it was determined that m-hydroxybenzoylecgonine had the same retention time and ion ratios as the TLC immunoreactive spot. Furthermore, m-hydroxybenzoylecgonine proved to be immunoreactive. Ten meconium samples immunoreactive for benzoylecgonine were analyzed by GC/MS. Results before and after hydrolysis with beta-glucuronidase (type IX) showed free m-hydroxybenzoylecgonine comprising 59 to 94% of the total m-hydroxybenzoylecgonine and showed total m-hydroxybenzoylecgonine values ranging from 0.2 to 6.3 times as high as benzoylecgonine. Therefore, m-hydroxybenzoylecgonine appears to be a quantitatively important cocaine metabolite in meconium, which is responsible for a significant portion of the discrepancy between benzoylecgonine concentrations in meconium extracts as measured by immunoassay and GC/MS.
Assuntos
Cocaína/análogos & derivados , Mecônio/química , Artefatos , Cocaína/análise , Humanos , ImunoensaioRESUMO
The levels of Ca and P in serum and urine, and the renal functions: Ccr. TRCa and TRP were determined in 43 patients with chronic Cor Pulmonale complicated with respiratory insufficiency. The results showed that the level of SCa decreased in 72.1% (31/43) and after correction by serum protein 58.1% (25/43). The SP was normal in 60.5%, (26/43). UCa and UP reduced in 62.8% (27/43) and 88.4% (38/43) respectively.
Assuntos
Cálcio/metabolismo , Fósforo/metabolismo , Doença Cardiopulmonar/metabolismo , Insuficiência Respiratória/metabolismo , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença Cardiopulmonar/complicações , Insuficiência Respiratória/etiologiaRESUMO
OBJECTIVE: Acute respiratory distress syndrome (ARDS) is a common scenario associated with hepatic warm ischemia and reperfusion (I/R) injury after shock or hemorrhage. Inflammation of lung parenchyma and increase in matrix metalloprotease 9 (MMP-9) activity have been implicated in ARDS. In this study, we aimed to investigate the protective efficacy of curcumin treatment against hepatic I/R-induced lung function impairment. METHODS: Thirty Sprague-Dawley male rats were evenly divided into 3 groups: a sham group, a hepatic I/R group, and a group treated with curcumin (15 mg/kg/d) 15 minutes before ischemia and every 24 hours for the next 48 hours. Ischemia was induced by occluding the hepatic artery and portal vein for 30 minutes. The clamps were then released and the abdominal incision was closed. Pulmonary function test was conducted after 48 hours of reperfusion. We also examined serum alanine transaminase (ALT) level and degrees of tumor necrosis factor α (TNF-α) and MMP-9 activity in the lung tissue. RESULTS: Hepatic I/R injury decreased the ratio of residual volume to total lung capacity (RV/TLC), chord compliance (Cchord), and maximum midexpiratory flow (MMEF; P < .05), and increased inspiratory resistance (RI; P < .05), characterized as combined obstructive and restrictive lung disease. Treatment with curcumin markedly improved RV/TLC, Cchord, and MMEF and decreased RI (P < .05). In addition, curcumin treatment reduced serum ALT level and degrees of TNF-α level and MMP-9 activity in the lungs. CONCLUSIONS: Curcumin attenuated hepatic I/R-induced combined restrictive and obstructive lung disease by reducing lung inflammation and MMP-9 activity.
Assuntos
Curcumina/farmacologia , Hepatopatias/tratamento farmacológico , Fígado/cirurgia , Pneumopatias Obstrutivas/prevenção & controle , Lesão Pulmonar/prevenção & controle , Pulmão/efeitos dos fármacos , Metaloproteinase 9 da Matriz/metabolismo , Inibidores de Metaloproteinases de Matriz/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Isquemia Quente/efeitos adversos , Alanina Transaminase/sangue , Animais , Biomarcadores/sangue , Citoproteção , Modelos Animais de Doenças , Fígado/irrigação sanguínea , Hepatopatias/etiologia , Pulmão/enzimologia , Pulmão/fisiopatologia , Pneumopatias Obstrutivas/enzimologia , Pneumopatias Obstrutivas/etiologia , Pneumopatias Obstrutivas/fisiopatologia , Lesão Pulmonar/enzimologia , Lesão Pulmonar/etiologia , Lesão Pulmonar/fisiopatologia , Masculino , Ratos Sprague-Dawley , Traumatismo por Reperfusão/etiologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
OBJECTIVE: Reperfusion of the rat kidney has been shown to up-regulate cysteinyl leukotriene-1 receptor, an asthma-associated gene in human bronchioles, and increase expression of leukotriene D4. In this study, we aimed to investigate the efficacy of MK-571, a leukotriene D4 inhibitor, against hypersensitivity induced by kidney ischemia and reperfusion (I/R)-associated acute kidney injury. METHODS: Sprague-Dawley male rats were divided into 3 study groups: a sham-operated group, a kidney I/R group, and a group treated with MK-571 before the kidney I/R injury: MK-571 (5 mg/kg) was administered intraperitoneally 15 minutes before ischemia and every 12 hours after reperfusion up to 24 hours. Ischemia was conducted by bilateral occlusion of renal pedicles for 45 minutes, followed by releasing the clamps and closing the abdominal incision. Respiratory function was tested 24 hours after reperfusion, with the use of a 2-chamber whole body plethysmograph for conscious rats. Blood samples, pulmonary bronchoalveolar lavage fluid, and lung tissues were collected at the end of study. In 10 rats, urine was collected at baseline and the end of study. RESULTS: Compared with the sham group, kidney I/R injury markedly increased enhanced pause (Penh) index during methacholine challenge test (P < .05), suggesting airway hypersensitivity; it also increased in inflammatory response and levels of hydroxyl radical production and lipid peroxidation in the lungs. In contrast, in MK-571-treated rats, Penh was muted during methacholine challenge test (P < .05). CONCLUSIONS: Kidney I/R injury induces airway hypersensitivity to methacholine challenge test and inflammatory response and oxidative stress in the lungs. Treatment with MK-571, a leukotriene D4 inhibitor, effectively attenuates airway hypersensitivity, pulmonary inflammatory response, and lung and kidney injury.
Assuntos
Injúria Renal Aguda/tratamento farmacológico , Hiper-Reatividade Brônquica/prevenção & controle , Broncoconstrição/efeitos dos fármacos , Broncodilatadores/farmacologia , Rim/efeitos dos fármacos , Antagonistas de Leucotrienos/farmacologia , Pulmão/efeitos dos fármacos , Propionatos/farmacologia , Quinolinas/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Injúria Renal Aguda/complicações , Injúria Renal Aguda/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Biomarcadores/metabolismo , Hiper-Reatividade Brônquica/etiologia , Hiper-Reatividade Brônquica/metabolismo , Hiper-Reatividade Brônquica/fisiopatologia , Broncodilatadores/administração & dosagem , Modelos Animais de Doenças , Esquema de Medicação , Radical Hidroxila/metabolismo , Mediadores da Inflamação/metabolismo , Injeções Intraperitoneais , Rim/metabolismo , Antagonistas de Leucotrienos/administração & dosagem , Peroxidação de Lipídeos/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/fisiopatologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Propionatos/administração & dosagem , Quinolinas/administração & dosagem , Ratos Sprague-Dawley , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/metabolismo , Fatores de TempoRESUMO
OBJECTIVES: Lung ischemia and reperfusion (I/R) injury is the major complication subsequent to cardiopulmonary bypass surgery and lung transplantation. Lung I/R injury frequently induces cardiac dysfunction leading to significant mortality. So far, the literature on therapeutic interventions in cardiac dysfunction and myocardial injury is still scarce. In this study, we examined the efficacy of N-acetylcysteine (NAC) administration against lung I/R injury-induced cardiac dysfunction. METHODS: Lung ischemia was established by occluding the left lung hilum for 60 minutes, followed by 2 hours of reperfusion. Studies were performed in 3 groups: sham-operated (same surgical procedure except vessel occlusion; N = 8), lung I/R injury (N = 12), and NAC-administered group (N = 12). The cardiac function was assessed using simultaneous left ventricular (LV) pressure and volume measured via a high-fidelity pressure-volume catheter. Myocardial injury was assessed based on serum creatine kinase muscle brain fraction (CK-MB) and troponin I (cTnI) level, and lung injury based on the degree of protein concentration in lung lavage. We also examined the degrees of myocardial lipid peroxidation and hydroxyl radical production with and without NAC. RESULTS: During lung ischemia, LV stiffness increased with relative intact contractility. After 2 hours of reperfusion, LV contractility decreased with dilated and stiffened ventricle, along with apparent myocardial and lung injury. NAC administration effectively attenuated heart and lung injury, and ameliorated impaired LV contractility and stiffening resulting from lung I/R injury. CONCLUSIONS: NAC administration reduced lung I/R-induced increases in myocardial hydroxyl radical production and lipid peroxidation, and ameliorated LV contractility and stiffening.
Assuntos
Acetilcisteína/farmacologia , Antioxidantes/farmacologia , Lesão Pulmonar/tratamento farmacológico , Pulmão/irrigação sanguínea , Contração Miocárdica/efeitos dos fármacos , Traumatismo por Reperfusão/tratamento farmacológico , Disfunção Ventricular Esquerda/prevenção & controle , Função Ventricular Esquerda/efeitos dos fármacos , Animais , Biomarcadores/sangue , Líquido da Lavagem Broncoalveolar/química , Creatina Quinase Forma MB/sangue , Citoproteção , Modelos Animais de Doenças , Radical Hidroxila/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lesão Pulmonar/sangue , Lesão Pulmonar/fisiopatologia , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/fisiopatologia , Fatores de Tempo , Troponina I/sangue , Disfunção Ventricular Esquerda/sangue , Disfunção Ventricular Esquerda/patologia , Disfunção Ventricular Esquerda/fisiopatologia , Pressão Ventricular/efeitos dos fármacosAssuntos
Heme , Peroxidase , Peroxidases , Amidas , Apoproteínas , Fenômenos Químicos , Química , Humanos , Leucócitos/enzimologia , Porfirinas/análiseAssuntos
Encéfalo/enzimologia , Proteína Básica da Mielina/isolamento & purificação , Bainha de Mielina/enzimologia , Fosfoproteínas Fosfatases/isolamento & purificação , Ativação Enzimática , Humanos , Isoenzimas/isolamento & purificação , Isoenzimas/metabolismo , Cinética , Manganês/farmacologia , Peso Molecular , Proteína Básica da Mielina/metabolismo , Fosfoproteínas Fosfatases/metabolismoRESUMO
Bovine central-nervous-system myelin was found to contain both Ca2+-activated and cyclic AMP-dependent protein kinases. Each enzyme possesses unique solubility and substrate-specificity characteristics. The Ca2+-activated enzyme, like its substrate (basic protein), is probably deeply embedded in the neural membrane, whereas the cyclic AMP-dependent kinase appears to be much less tightly associated with myelin. Treatment of insoluble myelin fraction housing the Ca2+-activated kinase with phospholipase A2 and phospholipases A2 + C causes a decrease in its ability to become activated by Ca2+. This can be countered by phosphatidylserine and phosphatidylethanolamine. Whereas the activity of the Ca2+-activated membrane-associated kinase is inhibited by chlorpromazine, dibucaine, melittin and Triton X-100, it is activated by certain phorbol diesters (4 beta-phorbol 12-myristate 13-acetate, 4 beta-phorbol 12,13-didecanoate, 4 beta-phorbol 12,13-dibenzoate and 4 beta-phorbol 12,13-diacetate), which appear to exert this effect by lowering the concentration of Ca2+ normally required for the activation of this enzyme. Together these results suggest that the activation of the membrane-associated kinase by Ca2+ most probably requires certain lipids, perhaps those already present in the membrane.
Assuntos
Bainha de Mielina/enzimologia , Proteínas Quinases/metabolismo , Animais , Sítios de Ligação , Cálcio/farmacologia , Calmodulina/farmacologia , Bovinos , AMP Cíclico/farmacologia , Ativação Enzimática/efeitos dos fármacos , Técnicas In Vitro , Ésteres de Forbol/farmacologia , Fosfolipases/farmacologia , Fosfolipídeos/farmacologia , Fosforilação , Inibidores de Proteínas Quinases , Solubilidade , Especificidade por SubstratoRESUMO
A series of thiadiazole derivatives of carbonic anhydrase inhibitors were prepared and their physicochemical properties and pharmacological activities such as corneal permeabilities, inhibition of carbonic anhydrase activities were evaluated. The solubilities and pKa values were determined in varied pH of phosphate buffers at 35 degrees C after equilibrium. Intrinsic solubility and pKa value were calculated from the plot of solubility versus the reciprocal of hydrogen ion concentration. The distribution coefficient was determined in the system of octanol/pH 7.65 phosphate buffer. As a result, the sigma (Hammett constant) and pi (hydrophobic substituent constant) values of substituents were found to be correlated to the logarithm of Ka and partition coefficient. Corneal permeabilities of the analogue were determined in a specially designed diffusion cell using excised rabbit cornea, which ranged from 1.32 x 10(-5) (compound II) to 3.48 x 10(-7) cm/sec (compound VI). Compound with high permeability might be expected to be absorbed well after topical administration into the eye. The methodology of pH-stat was used to determine the inhibition of the carbonic anhydrase activity of the analogue. The IC50 values of the analogue around 10(-8) M as determined were less than that of acetazolamide. The results suggest that the analogue had good pharmacological activity. Finally, an equation for quantitative structure-activity relationship was established for the analogue, which is as follows: [formula: see text]