Effects of gallstone solvents on commonly used catheters

PURPOSE

To determine what interaction and effect different cholesterol gallstone solvents have on catheters used for gallstone chemolysis.

MATERIALS AND METHODS

Five types of catheters used for biliary procedures were chosen: polyethylene, Percuflex, silicon, Silitek, and polyurethane. The solvents chosen were methyl tert-butyl ether, ethyl propionate, isopropyl acetate, and N-propyl acetate. After incubation of the catheters in the solvents for 72 hours, they were air dried. Weight and area changes were determined for each catheter. Additionally, carbon-13 nuclear magnetic resonance (NMR) spectroscopy was performed for analysis of composition changes.

RESULTS

Three catheters--silicone, Silitek, and polyurethane--showed changes in their physical characteristics that would make them less desirable for stone chemolysis. The silicone catheter showed changes in elastic texture as well as marked weight reduction. The Silitek and polyurethane catheters had similar, but less dramatic changes. C-13 NMR analysis of collected solvents showed that commonly used plasticizers were leached out of some catheters.

CONCLUSION

These results suggest that all catheters are not suitable for use with all solvents. The choice of catheter should be made based on the solvent in use. The polyethylene catheter performed best under the conditions and endpoints used in this study.

[Ultrasonography in differential diagnosis of peripheral pulmonary diseases]

In 87 patients with peripheral pulmonary diseases either adhesive or close to the pleura, who were examined, ultrasonographically 64 had lung cancer and 23 benign lesions were confirmed histopathologically. Five sonographic features including configuration, echogenicity patterns, bronchial air phase in foci, margin, and pleural involvement were significantly different between malignant and benign diseases (P < 0.01). The differential ultrasonography used in this series showed a sensitivity of 61% (14/23), a specificity of 95% (61/64), and an accuracy of 86% (75/87). The results demonstrate that ultrasound is helpful in differentiating the malignant lesion from the benign one in the peripheral lung near the pleura.

Localized expression of the H-ras proto-oncogene during Ilyanassa development

We have immunostained Ilyanassa embryos with an antibody to the ras protein and shown that the ras gene (1) is not expressed from early cleavage through the gastrula stage, but (2) is expressed during organogenesis by both normal and lobeless embryos, (3) that the ras protein is first synthesized from the third day of development in the normal embryo and from the fifth day of development in the lobeless embryo, and (4) that the expression of the ras protein is localized in mesodermal lineages of both normal and lobeless embryos.

Postsynaptic potentials and morphological features of tectal cells in homing pigeons

In this study postsynaptic potentials responding to the electrical stimulation of the optic nerve and the nucleus isthmi pars parvocellularis (Ipc) were intracellularly recorded from 86 tectal cells in pigeons, 13 of which were marked with Lucifer yellow (LY). According to types of postsynaptic potentials and their succession, the postsynaptic responses could be classified into four types: excitatory postsynaptic potential (EPSP)-inhibitory postsynaptic potential (IPSP) sequence (EI type), E, I and IE types. Among them, E or EI responses were mainly produced to the optic nerve stimulation, while the electrical stimulation of the Ipc elicited I responses in more than half the recorded cells. LY-marked tectal cells included five ganglionic cells, four pyramidal cells, two bipolar cells and two stellate cells. The ganglionic cells were mainly located in tectal layers III and IV, whereas the others were in layer II. It appears from both intracellular recordings and fluorescent markings that there is some correlation between the morphological features and the postsynaptic response types of tectal cells.

[C3 production by peripheral blood monocytes in patients with membranoproliferative glomerulonephritis and poststreptococcal glomerulonephritis]

Peripheral blood monocytes (PBM) and T cells from patients with membranoproliferative glomerulonephritis (MPGN) and poststreptococcal glomerulonephritis (PSAGN) were measured for the production on C3 and interferon-gamma respectively using an enzyme-linked immunosorbent assay. Testing of MPGN and PSAGN patients at acute stage showed that C3 levels by PBM were significantly higher than those of normal controls, whereas the levels of PSAGN patients at convalescent stage dropped within the range of normal controls. Levels of C3 production by PBM inversely correlated with serum C3 in both MPGN and PSAGN patients. Interferon-gamma production by T cells of MPGN patients were significantly higher than those of normal controls, while in PSAGN patients the levels, although not significantly elevated at acute stage, increased significantly at convalescent stage. These results suggest that hyperproduction of C3 by PBM in both hypoC3 disorders is likely due to activation of the cells by not yet determined antigens or immune complexes, but the effects of T cells on the activated PBM in MPGN differ from in PSAGN patients probably due to distinct antigens or immune complexes.

Effect of gold compounds on the activity of adenylyl cyclase in human lymphocyte membranes

OBJECTIVE

To determine the effects of aurothioglucose, aurothiomalate, and auranofin on basal and forskolin-activated adenylyl cyclase activity in human total lymphocyte membranes, and in membranes of T and B lymphocyte subsets.

METHODS

Membranes were isolated from human total lymphocytes and T and B cell subsets. The effects of gold compounds on basal and forskolin-stimulated activity of adenylyl cyclase were measured by radioassay.

RESULTS

The gold compounds inhibited adenylyl cyclase activity. This inhibitory effect required the presence of both the sulfhydryl ligands and aurous cation.

CONCLUSION

Regulation of lymphocyte adenylyl cyclase by gold compounds represents a potential mode of action of these drugs in rheumatic diseases.

Blockers of potassium channels reduce the outward dark current in rod photoreceptor inner segments

The dark current of single isolated toad rods was monitored by drawing either the inner segment or the outer segment into a suction electrode. The potassium-channel blockers tetraethylammonium (TEA) and 3,4-diaminopyridine (DAP) reduced the amplitude of the dark current when applied to the inner segment. Both drugs were less effective when applied to the outer segment, suggesting that they act at the inner segment to block part of the outward path for the dark current. In addition, DAP affected the kinetics of the light response, possibly by affecting internal pH.

[Determination of cholesterol in natural bezoar by gas chromatography]

A gas chromatographic method for the determination of free and total cholesterol in natural bezoar has been established in this report. The method is simple, specific and accurate. The free and total cholesterol contents in three kinds of bezoar are between 0.072% to 0.214% and 0.546% to 0.608% respectively.

[HPTLC densitometric determination of free bile acids in bezoar]

Cholic acid (CA), chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) which are extracted with CH3OH from Bezoar can be separated on HPTLC silica gel plate (made in China) with isooctane-n-butyl acetate-acetic acid (4:2:1), and the three bile acids were determined by TLC densitometry.

Tubulin binds specifically to the signal-transducing proteins, Gs alpha and Gi alpha 1

Participation of cytoskeletal elements in regulation of hormonal response and responsiveness has been suggested by several laboratories. Addition of dimeric tubulin to rat cerebral cortex synaptic membranes causes stable inhibition of adenylyl cyclase, and the molecular basis for this effect appears to require a direct interaction between tubulin and G proteins. To test whether such tubulin-G protein interaction occurred, several purified G proteins were bound to nitrocellulose, and 125I-tubulin overlay studies were performed. 125I-Tubulin bound to the alpha subunits of Gs and Gil with high specificity and an apparent Kd of approximately 130 nM. Other G protein alpha subunits (alpha i2, alpha i3, alpha 0, and transducin) displayed a much lower affinity for tubulin, despite the much closer relationship of those proteins to alpha il than to alpha s. Association of beta gamma subunits with alpha il or alpha s did not alter the binding of tubulin to these G protein heterotrimers, and the binding of a hydrolysis-resistant GTP analog to the alpha subunits was similarly without effect. These results suggest that tubulin forms complexes with specific G proteins and these complexes might provide a locus for the interaction of cytoskeletal components and signal transduction cascades. These results also provide evidence of a functional distinction among the closely related alpha i subtypes.

Effect of therapy on bronchial hyperresponsiveness in the long-term management of asthma

The aim of this study was to determine if prophylactic therapy leads to a reduction in the severity of bronchial hyperresponsiveness (BHR) in subjects with severe asthma. Measurements of bronchial responsiveness to histamine were made in two groups of subjects for periods up to 2 years. Thirteen subjects in the study group took regular medication and used a home monitor of airway function to determine the medication requirements needed to maintain optimal airway function. A control group of eleven subjects was managed with the same drugs but without daily monitoring and without any attempt to keep daily lung function at optimal levels. Subjects in the study group had a 10- to 100-fold decrease in the severity of BHR, which was independent of the improvement in baseline lung function. All but one subject in the study group became symptom free and six were able to maintain the improvement in BHR and symptoms on reduced medication. There was no change in the severity of BHR or in the baseline lung function in the control group. It is concluded that it is possible to reduce the severity of BHR in subjects with severe asthma by the use of pharmacological agents. This reduction in severity appears to require the long-term use of medications, including aerosol corticosteroids, with daily home monitoring to allow adjustment of the amount of treatment required.

Prevalence of bronchial hyperresponsiveness and asthma in a rural adult population

The prevalence of bronchial hyperresponsiveness in adult populations is not known. To document its prevalence and distribution and to determine the factors associated with it, a random sample of the adult population of Busselton, Western Australia, was studied. Spirometric function, bronchial responsiveness to histamine, and atopic responses to skin prick tests were measured. Respiratory symptoms were determined by questionnaire. Data were obtained from 916 subjects. Of these, 876 underwent a histamine inhalation test and bronchial hyperresponsiveness to histamine (defined as a dose of histamine provoking a 20% fall in FEV1 equal to or less than 3.9 mumol) was found in 10.5%. Another 40 subjects with poor lung function were tested with a bronchodilator and 12 were found to have bronchial hyperresponsiveness (defined as a greater than 15% increase in FEV1), making the total prevalence of bronchial hyperresponsiveness 11.4%. The prevalence of current asthma, defined as bronchial hyperresponsiveness plus symptoms consistent with asthma in the last 12 months, was 5.9%. The distribution of bronchial hyperresponsiveness in the studied population was continuous. There was a significant association between it and respiratory symptoms, atopy, smoking, and abnormal lung function (p less than 0.001 for all associations). There was no association with age, sex, or recent respiratory tract infection.

Visual responses of neurons in the avian nucleus isthmi

Electrophysiological responses of neurons to visual and auditory stimulation are extracellularly recorded from the pigeon isthmic area. Cobalt sulfide markings show that only visual units are localized within the nucleus isthmi pars parvocellularis (Ipc) and pars magnocellularis (Imc), while visual-auditory bimodal units are localized outside. Visual units respond to black or white targets moving through their receptive fields (RFs). The RF centers are mainly distributed in the contralaterally lower visual field. The rostral Ipc and Imc receive information from the nasal visual field, and the caudal part of the Ipc and Imc corresponds to the temporal field. Therefore, both Ipc and Imc are visual centers instead of auditory centers as described before.

Prevalence and nature of bronchial hyperresponsiveness in subjects with chronic obstructive pulmonary disease

The prevalence, nature, and severity of bronchial hyperresponsiveness in subjects with chronic obstructive pulmonary disease (COPD) is not known. To determine these factors, a 1 in 4 random sample of adults attending the Busselton population survey was studied. Subjects answered a modified Medical Research Council questionnaire and had spirometric function tested. They were defined as having COPD or asthma from the questionnaire. Bronchial responsiveness to histamine was measured using the rapid method, and results in the subjects with COPD were compared with those in asthmatic subjects with abnormal lung function. Fifty-nine subjects with COPD had a histamine inhalation test, and of these, 27 had bronchial hyperresponsiveness (BHR) (PD20FEV1 less than 3.9 mumol). The position of the dose response curves of the subjects with COPD overlapped considerably with those obtained from the 17 asthmatics. The geometric mean values for PD20FEV1 for these 2 groups were significantly different (p less than 0.001). There was a good correlation between FEV1/FVC and PD20FEV1 values in the subjects with COPD but not in the asthmatic subjects. Pretreatment with 600 micrograms of aerosolized fenoterol significantly improved the PD20FEV1 values in 11 subjects with COPD (1.26 to 6.16 mumol; p less than 0.001). The results suggest that approximately half the subjects with COPD in a general population have BHR but this BHR has different characteristics from that occurring in asthmatic subjects.

The effect of acetylcholine on neurones of the amphibian nucleus isthmi

In the bird, histochemical and biochemical data suggest that the tectal input into nucleus isthmi is of a cholinergic nature. In the present study the response of toad (Bufo bufo gargarizans) isthmic neurones to acetylcholine was investigated using conventional extracellular recording techniques and ionophoresis. The results show isthmic cells to be strongly excited by acetylcholine (ACh), whereas neurones in the neighbouring areas show minimal sensitivity. Atropine sulphate completely blocked the response to acetylcholine and greatly decreased activity induced by visual stimulus. The present data show that acetylcholine mimics one of the physiological transmitters in the nucleus isthmi.

Electrophysiological studies on the nucleus isthmi of the lizards Gekko gekko and Shinisaurus crocodilurus

This report studies visual responses of the isthmic units in Gekko gekko and Shinisaurus crocodilurus using extracellular recording and cobalt sulfide marking techniques. Our results indicate that: (i) the nucleus isthmi pars magnocellularis (Imc) is a visual center; (ii) there are luxotonic units in Imc; (iii) Imc units respond vigorously to moving contrast targets, of which 35% units burst only at the moment when targets are moving into and out of their receptive fields, none react to either tactile or auditory stimulation; (iv) there exist binocular units in Imc; and (v) visual field is topographically projected onto Imc.

The action of prazosin and propylene glycol on methoxamine-induced bronchoconstriction in asthmatic subjects

The effect of 1 mg inhaled prazosin on bronchoconstriction induced by methoxamine was investigated in seven asthmatic subjects. Prazosin caused significant inhibition of the methoxamine-induced bronchoconstriction in six of the seven patients. These findings suggest that methoxamine produces bronchoconstriction in asthmatic subjects via stimulation of alpha-adrenoceptors. In previous studies propylene glycol has been used as a vehicle for delivery of prazosin. This substance was found to cause significant inhibition of methoxamine effects and to shift the dose response curve to histamine to the right in four of seven patients.

The shape of the dose-response curve to histamine in asthmatic and normal subjects

In order to determine the shape of the dose-response curves of the human airways to bronchial challenge, changes in forced expiratory volume in one second (FEV1) after inhaled histamine were measured in 8 current asthmatic, 2 mildly asthmatic, and 10 normal subjects. The challenges were continued until a plateau was reached (in all the normal and in the 2 mildly asthmatic subjects), or the FEV1 had fallen by 60%. A sigmoidal equation was fitted to the data points to obtain values for alpha (the position constant) and beta (the slope constant). All the normal and the 2 mildly asthmatic subjects reached a plateau value for fall in FEV1. Current asthmatics were differentiated from normal and mildly asthmatic subjects by the failure to reach a plateau at a 60% fall in FEV1 by higher values for alpha (greater sensitivity to histamine) and by higher values for beta. Ipratropium bromide (an atropinelike drug), in doses that completely inhibited the effects of methacholine, caused no change in the shape or position of the curves in normal or asthmatic subjects. It is concluded that the nature of the airway response to histamine is different in asthmatic from that in normal subjects. It is possible that asthmatics lack a normal mechanism that inhibits severe airway narrowing during histamine challenge.

Somatic embryogenesis inEchinochloa crusgalli

A white, compact embryogenic tissue was obtained from young inflorescence segments ofEchinochloa crusgalli (barnyard grass) cultured on Murashige and Skoog's medium containing various concentrations and combinations of 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine. Histological and scanning electron microscopic studies revealed that the white compact callus contained embryoids in various stages of development. Typical embryoids were bipolar and possessed scutella, coleoptiles and coleorhizae. The embryogenic nature of the callus was maintained throughout eight to ten subcultures spanning more than six months. A high frequency of plant regeneration was obtained when the 2,4-D concentration was reduced or 2,4-D was removed from the medium.

Immature chicken B cells with immunocompetence restricted to IgM type do not elicit the formation of germinal centres

Chickens depleted of both T and B cells were restored with T cells and with immature B cells capable of producing IgM only, and immunized with sheep red blood cells. These chickens developed strikingly few germinal centres, in marked contrast to controls which received normal adult B cells.

Comparison of in vivo and in vitro responses to histamine in human airways

The study was designed to compare in vivo responses to histamine in 14 patients prior to thoracotomy with in vitro responses to histamine of both parenchymal and bronchial tissue. Although a wide range of responsiveness occurred in vivo, as measured by the histamine inhalation test, the variation in the in vitro dose-response curves was negligible. There was no correlation between the dose of histamine that resulted in a 20% reduction in forced expiratory volume in one second and the concentration of histamine producing 50% of the maximal response in vitro. These findings raise the possibility that airway hyperresponsiveness may not result from an intrinsic abnormality of airway smooth muscle.

Effect of aerosol fenoterol on the severity of bronchial hyperreactivity in patients with asthma

Beta adrenergic agents given by aerosol decrease the responsiveness of the airways to histamine and methacholine in subjects with asthma, causing a shift of the dose response curve to the right. To find out whether the shift is related to the dose of beta adrenergic agent given and to determine the duration of the reduced responsiveness, eight subjects with asthma were given histamine inhalation tests after inhaled saline and after increasing doses of inhaled fenoterol on different days. The histamine inhalation tests were repeated at hourly intervals for five hours after a selected dose of fenoterol. Fenoterol caused a dose related shift to the right of the histamine dose response curve in each subject and in some the dose response relationship reached the "non-symptomatic range." The shift in the dose response curve was short lived and had returned towards the control position within three hours in all subjects. There was no change in shape of the curves at the time of maximal shift. The results show that inhaled fenoterol greatly reduces the airway responsiveness to histamine, but up to 400 micrograms of fenoterol every four to five hours may be needed to keep the responsiveness of the airways in the non-symptomatic range.

Rapid method for measurement of bronchial responsiveness

A rapid, simple method for measuring bronchial responsiveness to inhaled histamine is described. The method was used to obtain dose response curves in 50 atopic subjects with varying respiratory and nasal symptoms. The cumulative dose of histamine which caused a 20% fall in the one second forced expiratory volume (PD20-FEV1) varied between 0.046 and greater than 3.9 mumol and correlated with the severity of symptoms. The reproducibility of the PD20-FEV1, determined from duplicate measurements in 15 subjects with varying degrees of bronchial responsiveness was found to be satisfactory. When the PD20-FEV1 from this rapid method was compared with that obtained from the dosimeter method no significant difference was found. The dose delivered by this method was shown to be cumulative.

Neuroanatomy and electrophysiology of the lacertilian nucleus isthmi

Horseradish peroxidase (HRP) tracings showed a bidirectional connection between the optic tectum (OT) and the ipsilateral nucleus isthmi (NI) pars magnocellularis (Imc) in nocturnal Gekko gekko and diurnal Shinisaurus crocodilurus. We found that, in addition to a direct neuronal pathway, there is an indirect pathway from OT to Imc via the nucleus profundus mesencephali (NPM). The morphology of cells in OT, NPM and NI was studied. Visual units extracellularly recorded from NI were located within Imc based on cobalt sulphide markings. They responded to moving contrast targets, without reacting to tactile and auditory stimulation. HRP and Golgi-Cox studies showed that Imc is a nucleus independent of its parvocellular partner, Ipc.

Nucleus isthmus of toad is secondary visual center

Visual responses of 148 units have been recorded with micropipettes from the left nucleus isthmus areas of toads (Bufo bufo gargarizans), their auditory and tactile responses also examined, and 122 recording sites marked with cobalt sulphide. This study indicates that: (i) 118 units responding solely to visual stimuli are found within the nucleus, and 4 multisensory units outside, (ii) there exist a visual field map and binocular units in the nucleus, and (iii) response latencies of the isthmic units to a spot of light range from 120 to 540 msec, with no correlation with recording sites.

Visual field topography and binocular responses in frog's nucleus isthmi

Visual responses of 125 units have been extracellularly recorded with glass micropipettes from the left nucleus isthmi in the frog Rana nigromaculata, and 101 electrode tip positions marked with cobalt staining to reconstruct a visual field map in the nucleus. 80% of the units recorded show ON-OFF responses to a stationary spot of light and many are directionally selective in response to black or white targets moving through their receptive fields. All the cobalt-marked spots are within the nucleus, indicating that the nucleus isthmus proper is a restricted part of the frog visual system. There is a visual field map in the nucleus. The entire contralateral hemifield and the nasal 40 degrees of the ipsilateral hemifield project on the nucleus topographically. A cell-free band inside the nucleus is a boundary line separating the contralateral hemifield from the ipsilateral one. Dorsal to it is the contralateral field representation. The upper visual field projects on the rostral half of the nucleus and the central and medio-ventral portion of its caudal half. The lower field is represented on the dorsal and lateral part of the caudal half. Fifteen binocular units have been found from the nucleus, 13 of which are dominantly activated by the contralateral eye, the other two are almost equally excited by either eye. These binocular units are mainly situated in the medulla of the rostral half of the nucleus isthmus.

Visual field topography in the frog's nucleus isthmi

Responses to visual stimulation were extracellularly recorded with micropipettes from 125 neurons of the left nucleus isthmi in frogs, Rana nigromaculata, and 101 electrode tip positions were marked with cobalt staining. The present study indicates that: (1) the entire contralateral hemifield and the nasal 40 degree of the ipsilateral hemifield project on the nucleus isthmi topographically, and (2) there exist binocular units in this nucleus.