Adenoviral transfer of human aquaporin-1 gene to rat liver improves bile flow in estrogen-induced cholestasis.

Estrogens can cause liver cholestatic disease. As downregulation of hepatocyte canalicular aquaporin-8 (AQP8) water channels has been involved in estrogen-induced bile secretory failure, we tested whether the archetypal water channel AQP1 improves 17α-ethinylestradiol (EE)-induced cholestasis. EE administration to rats reduced bile flow by 50%. A recombinant adenoviral (Ad) vector encoding human AQP1 (hAQP1), AdhAQP1, or a control vector was administered by retrograde bile ductal infusion. Hepatocyte canalicular hAQP1 expression was confirmed by liver immunostaining and immunoblotting in purified membrane fractions. Accordingly, canalicular osmotic water permeability was markedly increased. Bile flow, either basal or bile salt-stimulated was significantly augmented by over 50%. The choleretic efficiency of endogenous bile salts (that is, volume of bile per µmol of excreted bile salt) was significantly increased by 45% without changes in the biliary bile salt composition. Our data suggest that the adenoviral transfer of hAQP1 gene to the livers of EE-induced cholestatic rats improves bile flow by enhancing the AQP-mediated bile salt-induced canalicular water secretion. This novel finding might have potential therapeutic implications for cholestatic diseases.

Fluorescence polarization studies on four biliproteins and a bilin model for phycoerythrin 545.

Fluorescence (excitation) polarization spectroscopy in the wavelength region of the bilin chromophores was applied to phycoerythrocyanin (CV-phycocyanin), phycocyanins 645 and 612, and phycoerythrin 545. The cryptomonad biliproteins - phycoerythrin 545 and phycocyanins 612 and 645 - were studied as both protein dimers having an alpha(2)beta(2) polypeptide structure and as alphabeta monomers. The cyanobacterial phycoerythrocyanin (CV-phycocyanin) was a trimeric oligomer. The changes in polarization across the spectrum were attributed to transfers of energy between bilins. Cryptomonad biliproteins are isolated as dimers. The similarities between their steady-state fluorescence polarization spectra and those of the corresponding monomers suggested that the monomers' conformations were analogous to the dimers. This supports the use of monomers in the study of dimer bilin organization. The unusual polarization spectrum of phycoerythrin 545 was explained using a model for the topography of its bilins. Obtaining the emission spectra of phycoerythrin 545 at several temperatures and a deconvolution of the dimer circular dichroism spectrum also successfully tested the bilin model. Circular dichroism spectroscopy was used to determine which polarization changes are formed by Förster resonance energy transfers and which may be produced by internal conversions between high- and low-energy states of pairs of exciton-coupled bilins. Attempts were made to assign energy transfer events to the corresponding changes in fluorescence polarization for each of the four biliproteins.

In vitro demonstration of cryosurgical augmentation of tumor immunity.

C57B1 mice bearing methylcholanthrene-induced fibrosarcomas (MCA-10) and receiving a single cryosurgical treatment to those tumors showed significantly greater humoral and lymphocyte-mediated cytotoxicity to MCA-10 target cells than did untreated tumor-bearing animals or mice which had undergone tumor amputation. Sera and lymphocytes from normal animals receiving crycosurgery demonstrated no immunity to the MCA-10 target cells. Specific immunity to the MCA-10 line following tumor cryosurgery was demonstrated since lymphocytes and sera from cryosurgically treated tumor-bearing mice were not cytotoxic to a different methylcholanthrene-induced sarcoma (MCAP) in C57 mice or a malignant melanoma (S91) being transferred in Balb/C mice. It can be concluded that cryosurgical treatment of the MCA-10 sarcoma does not produce heightened immunity to H-2 transplantation antigens, nor does it nonspecifically stimulate the immune system. Instead, the result of tumor cryosurgery appears to be a boosting of the immune response to the tumor-specific antigens of the sarcoma.

Comparison of responses to siguazodan, rolipram, and zaprinast in the feline pulmonary vascular bed.

The present study was undertaken to investigate and compare responses to the cyclic nucleotide phosphodiesterase inhibitors siguazodan (type III, guanosine 3',5'-cyclic monophosphate (cGMP)-inhibited adenosine 3',5'-cyclic monophosphate (cAMP)), rolipram (type IV, cAMP-specific), and zaprinast (type V, cGMP-specific) in the feline pulmonary vascular bed. When tone in the pulmonary vascular bed was raised to a high steady level with a constant infusion of the thromboxane mimic U46619 (9,11-dideoxy-11, alpha9alpha-epoxymethano prostaglandin F(2alpha)), intralobar injections of the three phosphodiesterase inhibitors caused dose-related decreases in lobar arterial pressure. In terms of relative vasodilator activity, rolipram was more potent at higher doses than siguazodan, which was more potent than zaprinast. The duration of the pulmonary vasodilator response to zaprinast was shorter than for siguazodan or rolipram. Furthermore, siguazodan and rolipram, but not zaprinast, decreased systemic arterial pressure when injected into the perfused lobar artery in the range of doses studied. The present data demonstrate that the three phosphodiesterase inhibitors have potent, long-lasting vasodilator activity in the pulmonary vascular bed of the cat. These data suggest that there is rapid turnover of cAMP and cGMP in the pulmonary circulation and indicate that phosphodiesterase enzyme types III, IV, and V may play an important role in the regulation of vasomotor tone in the feline lung.

Comparison of responses to novel nitric oxide donors in the feline pulmonary vascular bed.

Pulmonary vascular responses to the novel diazeniumdiolate nitric oxide (NO) donors diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt, were investigated and compared in the intact-chest cat. Under conditions of controlled blood flow, when tone in the pulmonary vascular bed had been raised to a high steady level, intralobar injections of diethylamine/NO (0.3-10 microg), diethylenetriamine/NO (10-30 microg), spermine/NO (10-30 microg), sulfite/NO (10-30 microg), and angeli's salt (10-30 microg) caused dose-related decreases in lobar arterial pressure without changing left atrial pressure. In terms of relative vasodilator activity in the pulmonary vascular bed, the dose of the compounds that decreased lobar arterial pressure 4 mm Hg (ED(4) mm Hg) was significantly lower for diethylamine/NO compared to S-nitroso-N-acetylpenicillamine which was significantly less than diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt. The half-life of the vasodilator responses, as measured by 50% response recovery time, to diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt was similar for doses with similar magnitudes of vasodilation, while the half-life to S-nitroso-N-acetylpenicillamine was significantly less than the diazeniumdiolate NO donors. The present data demonstrate that the diazeniumdiolate NO donors diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli's salt have potent but relatively short-lasting vasodilator activity in the pulmonary vascular bed of the cat.

Mechanism of heightened tumor immunity induced by cryosurgery.

Sarcoma-bearing mice treated with cryosurgery demonstrated significantly greater tumor immunity (as measured by lymphocytoxicity assays) than untreated tumor-bearing mice (p less than .001). However, cryosurgically treated mice did not show greater cytotoxicity than tumor-bearing and tumor-amputated mice which were treated with frozen exogenous tumor antigen. These results suggested that the mechanism by which cryosurgery stimulates systemic tumor immunity is through the release of antigen from the neoplasm. Thus, tumor-bearing mice treated with cryosurgery in these experiments underwent definitive ablative therapy while at the same time they received active tumor immunotherapy.

Employment supports for people with mental illness.

People with psychiatric disabilities often require extensive support to maintain employment. The authors describe five areas that supported employment programs should carefully examine when creating a supportive workplace environment: "natural" co-worker supports, personal network supports, training supports, self-management supports, and organizational supports. The different support needs of persons with developmental disabilities and those with psychiatric disabilities are highlighted, particularly in regard to how social stereotypes of these two groups influence decisions about how to provide support. The authors also discuss strategies that can be used by transitional employment programs for creating more effective supports within the limitations of the transitional setting.

Hereditary gingival fibromatosis: identification, treatment, control.

Hereditary gingival fibromatosis, or HGF, is characterized by varying degrees of attached gingival hyperplasia. The authors describe a case of generalized severe hereditary gingival fibromatosis involving the maxillary and mandibular arches. Removal of excess gingival tissue by conventional gingivectomy dramatically improved the patient's appearance.

Cardiovascular effects of methacholine-induced airway obstruction in man.

Cardiovascular disease is the most frequent cause of death in people with chronic respiratory disease. The cause of this association has been attributed to airway obstruction leading to cardiovascular dysfunction (increased central blood pressure (BP) and aortic stiffness). However, this has never been experimentally tested. Methacholine is routinely used to stimulate airway function changes that mimic airway pathology. This study aimed to determine the cardiovascular effects of methacholine-induced airway obstruction. Fifteen healthy young adults (aged 22.9±2.5 years; 4 male; mean±S.D.) underwent a bronchial challenge test (randomized, blinded, cross-over design) in which they received nebulized methacholine inhalation in serially increasing concentrations (from 0.39 to 25 mg/ml) or saline (0.9%; control) on two separate days. Bronchoconstriction was assessed by forced expiratory volume at one second (FEV1) and cardiovascular effects by augmentation index, brachial BP, central BP, heart rate and aortic stiffness. Methacholine significantly decreased FEV1 from baseline to peak inhaled concentration compared with saline (-0.48±0.34 vs. -0.07±0.16 L; p<0.001), but there was no between-group change in augmentation index (1.6±7.0 vs. 3.7±10.2% p=0.49), brachial systolic BP (-3.3±7.6 vs. -4.7±5.7 mmHg; p=0.59), central systolic BP (-1.1±5.2 vs. -0.3±5.5 mmHg; p=0.73), heart rate (0.4±7.1 vs. -0.8±6.6 bpm; p=0.45) or aortic stiffness (0.2±1.3 vs. 0.8±1.8 m/s; p=0.20; n=12). Thus, methacholine induced airway obstruction does not acutely change brachial BP or central haemodynamics. This finding refutes the notion that airway obstruction per se leads to cardiovascular dysfunction, at least in healthy individuals in the acute setting.

Entamoeba histolytica meningoencephalitis diagnosed by trophozoites in cerebrospinal fluid.

Entamoeba histolytica meningoencephalitis has not been described in the modern literature, which is distinct from that caused by free-living amoebae. We report the first case of E. histolytica meningoencephalitis without liver or brain abscesses. Cerebrospinal fluid revealed 2 + very motile trophozoites. Our patient was successfully treated with intravenous metronidazole.

Higher rates of streptococcal colonization among children in the Pacific Rim Region correlates with higher rates of group A streptococcal disease and sequelae.

Group A streptococcal (GAS) pharyngeal colonization rates were determined among 1061 asymptomatic students in Hawaii and American Samoa where acute rheumatic fever rates are high. All GAS isolates were emm sequence typed. Although pharyngeal colonization rates were low in Hawaii (3.4%), Pacific Islander children had significantly higher colonization rates (5.7% vs. 1.2% in other ethnic groups, p <0.05). The colonization rate was higher in American Samoa (13%). Few emm types that were infrequently observed in symptomatic infections in Hawaii were repeatedly identified in both sites. These emm types were previously described among asymptomatic children suggesting a type-specific association with pharyngeal colonization.

Antitumor immune response following injection of neuraminidase-treated sarcoma cells.

Mice inoculated with MCA-10 sarcoma cells which had previously been incubated with Vibrio cholerae neuraminidase (VCN) demonstrated a significantly lower tumor incidence (9/26) than mice injected with untreated sarcoma cells (10/10) or sarcoma cells incubated with heat-inactivated neuraminidase (28/29) p less than .05. Rechallenge of nontumor-bearing mice from the VCN group with untreated sarcoma cells resulted in a low tumor incidence (4/11), indicating that these mice had developed systemic immunity following the initial injection of VCN-treated tumor cells. These mice also demonstrated significant lymphocytotoxicity against MCA-10 target cells compared with normal control mice (p less than .05). Subsequent cytotoxicity experiments, utilizing groin lymph node and splenic lymphocytes from mice five days following leg injection of VCN-treated, heat-inactivated VCN-treated or untreated MCA-10 cells, demonstrated that the mice injected with VCN-treated tumor cells demonstrated greater antitumor immunity both locally and systemically. This magnification of tumor immunity is postulated as the mechanism by which neuraminidase treated MCA-10 sarcoma cells grew less well in C57 mice than cells incubated with heat-inactivated VCN or cells left untreated.

Immunogenicity of N-[-4-(5-nitro-2-furyl)-2-thiazolyl]formamide-induced bladder cancer.

Five transplantable TCC initially induced by the carcinogen FANFT were systematically tested for individual immunogenicity and then for the presence of cross-reacting tumor antigens. The classic amputation challenge technique was used. Three of the 5 tumors were immunogenic, as determined by their ability to reduce the growth of a challenge tumor dose in mice immunized with the same bladder tumor. Prior immunization with one of the immunogenic tumors failed to reduce the incidence or growth of primary bladder tumors induced by the ingestion of 0.1% FANFT in C3H/HeJ mice. The lack of cross-reacting tumor antigens has important implications for the use of allogeneic tumor cells as an antigen source in immunotherapy.

Effects of U-37883A, a vascular selective KATP+ channel antagonist, in the pulmonary and hindlimb circulation.

The effects of the vascular selective nonsulfonylurea guanidine ATP-sensitive K+ (KATP+) channel-blocking agent U-37883A on vasodilator and vasoconstrictor responses were investigated in the pulmonary and hindlimb vascular beds of the cat. Under elevated tone conditions, both U-37883A and the sulfonylurea KATP+ antagonist, glibenclamide, attenuated pulmonary vasodilator responses to the KATP+ channel openers without altering responses to vasodilator agents that are reported to act by KATP(+)-independent mechanisms. However, under low resting-tone conditions, U-37883A enhanced pulmonary vasoconstrictor responses to the thromboxane mimic U-46619 and to prostaglandin (PG) F2 alpha and PGD2, whereas glibenclamide antagonized responses to U-46619 and the vasoconstrictor PG. In the hindlimb vascular bed, U-37883A and glibenclamide had no effects on responses to U-46619 in doses that inhibited vasodilator responses to the KATP+ channel opener levcromakalim. U-37883A and glibenclamide had no significant effect on baseline tone in the pulmonary or hindlimb vascular beds, and neither U-37883A nor glibenclamide altered pulmonary vasodilator responses to PGE1. The results of the present investigation show that U-37883A and glibenclamide, agents that are used in the study of vascular smooth muscle KATP+ channel mechanisms and attenuate vasodilator responses to the KATP+ channel openers, have pronounced effects on thromboxane/PG receptor-mediated vasoconstrictor responses in the pulmonary vascular bed of the cat.