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1.
Dermatology ; 223(2): 152-60, 2011.
Article in English | MEDLINE | ID: mdl-21997592

ABSTRACT

BACKGROUND: This study investigates the health-related quality of life in patients with vulvar lichen sclerosus (LS) and the patient-defined therapeutic benefit of clobetasol. METHODS: A survey analysis of 96 women with LS after treatment with clobetasol was performed. Quality of life was assessed with the Skindex-29. The Patient Benefit Index (PBI) was used to determine the therapeutic benefit. RESULTS: The overall response rate was 59.2%. Quality of life was most impaired by somatic symptoms (scale 'Symptoms' score 3.2) and emotional stress (scale 'Emotions' score 3.1), while social interactions (scale 'Functioning' score 1.9) played an inferior role (p < 0.001). Primary therapeutic goals 'to have confidence in the therapy' and 'to be free of itching' were achieved in 73.2 and 69.0% of patients who indicated the goal applied to them. The global PBI score was 3.06. In 93.2% of patients it was >1, indicating a potential benefit from clobetasol. CONCLUSION: Topical clobetasol is of potential therapeutic benefit for patients with vulvar LS and might therefore improve quality of life.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Clobetasol/therapeutic use , Quality of Life/psychology , Vulvar Lichen Sclerosus/drug therapy , Vulvar Lichen Sclerosus/psychology , Adolescent , Adult , Aged , Aged, 80 and over , Analysis of Variance , Chronic Disease , Emotions , Female , Humans , Middle Aged , Patient Satisfaction , Social Participation/psychology , Surveys and Questionnaires , Vulvar Lichen Sclerosus/physiopathology , Young Adult
2.
Ophthalmic Res ; 31(4): 280-6, 1999.
Article in English | MEDLINE | ID: mdl-10325543

ABSTRACT

The primary source of fibroblast growth factors (FGFs) is the retinal pigment epithelium (RPE). Investigations on FGF secretion in RPE primary cultures are hampered by the rapid run-down of cell vitality after a few passages. Therefore, long-term experiments require an alternative to primary cultures. We detected FGF-1 and FGF-2 in the established human K1034 cell line by immunohistochemistry. In addition, mRNA for both FGFs was found by RT-PCR. By immunohistochemistry, the signal was more pronounced with FGF-2 than with FGF-1. K1034 is capable of expressing both FGF-1 and FGF-2. With respect to these features, this cell line can be used as an alternative to primary cultured human RPE cells.


Subject(s)
Fibroblast Growth Factor 2/metabolism , Pigment Epithelium of Eye/metabolism , Base Sequence/genetics , Cell Line , Fibroblast Growth Factor 1 , Fibroblast Growth Factor 2/genetics , Humans , Immunohistochemistry , Molecular Sequence Data , Pigment Epithelium of Eye/cytology , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction
3.
Arch Otolaryngol Head Neck Surg ; 124(5): 529-33, 1998 May.
Article in English | MEDLINE | ID: mdl-9604978

ABSTRACT

OBJECTIVE: To investigate risk factors for sensorineural hearing loss (SNHL) in children after liver transplantation. DESIGN: Retrospective medical record review. SETTING: Pediatric tertiary care hospital. PATIENTS: One hundred twenty-five consecutive children who received liver transplants between March 1, 1987, and June 30, 1996. MAIN OUTCOME MEASURES: The presence of SNHL (bone conduction threshold of >35 dB of hearing loss in at least 1 frequency) and the cause of the liver abnormality in all 125 patients. In addition, among the subset of children who had biliary atresia and underwent transplantation before 2 years of age, the total dose (milligrams per kilogram of body weight) of aminoglycoside antibiotic medications (tobramycin sulfate, gentamicin sulfate, and amikacin sulfate) and of intravenous loop diuretic agents (furosemide) was compared between children with and without SNHL. RESULTS: Audiologic evaluations were available for 66 of 125 patients, 15 (12%) of whom have SNHL. Of 5 survivors with the short-bowel syndrome, 4 have severe to profound SNHL. Of 46 children who have biliary atresia and who underwent transplantation before 2 years of age, 8 (17%) have SNHL. Among the 26 evaluable children with biliary atresia undergoing liver transplantation before 2 years of age, logistic regression analysis revealed that the most important risk factor for SNHL was the cumulative dose of amikacin (P = .05). CONCLUSIONS: Children receiving liver transplants are at an increased risk for SNHL. Those with the short-bowel syndrome have the greatest prevalence of SNHL. Among the subset of children with biliary atresia receiving liver transplants before 2 years of age, statistical analysis demonstrates a dose-response relationship between the receipt of amikacin and the occurrence of SNHL.


Subject(s)
Hearing Loss, Sensorineural , Liver Transplantation , Postoperative Complications , Audiometry , Biliary Atresia/surgery , Child , Child, Preschool , Hearing Loss, Sensorineural/complications , Hearing Loss, Sensorineural/etiology , Humans , Infant , Liver Diseases/complications , Liver Diseases/surgery , Logistic Models , Retrospective Studies , Risk Factors , Short Bowel Syndrome/surgery
4.
Mol Vis ; 3: 10, 1997 Oct 15.
Article in English | MEDLINE | ID: mdl-9383333

ABSTRACT

PURPOSE: In this study, we evaluated a possible effect of acidic and basic fibroblast growth factor (aFGF, bFGF) on the proliferation of human retinal pigment epithelial (RPE) cells in culture. As the RPE is the primary source for bFGF in the retina, such an effect would suggest autocrinic actions of FGFs. METHODS: Primary cultures of human and porcine RPE and an established human RPE cell line (D407) were subjected to aFGF and bFGF at different culture conditions. Cell proliferation was determined using the BrdU non-radioactive nucleotide analogue assay, and total protein was measured colorimetrically. The cells were subjected to aFGF and bFGF from 0.1 to 100 ng/ml for 1 to 14 days. RESULTS: In the presence of 100 ng/ml bFGF, cell proliferation doubled from day 2 (143+/-12 units) to day 6 (227+/-17). This effect was neither seen without bFGF nor with aFGF at the same concentration. The stimulating effect of bFGF on cell proliferation was dose-dependent, the ED50 being around 1-10 ng/ml. The bFGF effect was markedly greater at high fetal calf serum concentration (10% vs. 1%). No bFGF effect was seen on cells of the established human RPE cell line D407 nor on primary cultures from porcine RPE. CONCLUSIONS: bFGF, in contrast to its analogue aFGF, stimulates cell proliferation in cultured human RPE cells. It may act as an autocrinic agent (secretion by and action on the same cell) and thus be a specific regulator for cell proliferation in repair and replacement of the RPE cell monolayer.


Subject(s)
Fibroblast Growth Factor 1/pharmacology , Fibroblast Growth Factor 2/pharmacology , Pigment Epithelium of Eye/metabolism , Animals , Cell Division/drug effects , Cell Line , Cells, Cultured , DNA/biosynthesis , Dose-Response Relationship, Drug , Eye Proteins/metabolism , Humans , Pigment Epithelium of Eye/drug effects , Swine , Time Factors
5.
Electroencephalogr Clin Neurophysiol ; 96(4): 357-70, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7635080

ABSTRACT

Auditory brain-stem responses (ABRs) were recorded from human subjects undergoing neurosurgical procedures which exposed the auditory nerve. Scalp recordings indicated that the latency of the negativity between waves I and II (In) and the latency of positive peak II (IIp) were shorter when the nerve was suspended in air than when the nerve was submerged in cerebrospinal fluid or saline, while earlier and later waves remained unaffected. These results could not be attributed to changes in stimulus or recording parameters or conduction velocity. Computational and somatosensory experimental evidence of stationary potentials generated by physical properties of the volume conductor, including changes in conductivity or geometry, are presented to develop a model of wave IIp generation. The results of this study suggest that wave IIp (and probably In) are manifestations of current flux asymmetries across conductivity boundaries created by the temporal bone-cerebrospinal fluid intradural space-brain-stem interfaces. The current flux asymmetries are generated as the propagating auditory nerve action potential crosses the conductivity boundaries. These results also indicate that the physical characteristics of the volume conductor and neural pathways must be considered when interpreting surface recorded evoked potentials.


Subject(s)
Evoked Potentials, Auditory, Brain Stem/physiology , Vestibulocochlear Nerve/physiology , Action Potentials , Brain Stem/physiology , Electroencephalography , Evoked Potentials , Humans
6.
Ren Physiol Biochem ; 18(4): 161-8, 1995.
Article in English | MEDLINE | ID: mdl-7481067

ABSTRACT

The established opossum kidney (OK) cell line serves as a model system for ion and substrate transport in the renal proximal tubule. Previous experiments on OK cells revealed a channel-mediated Na+ conductance which is regulated by intracellular pH (pHi). In this study we report on patch clamp experiments determining the properties and pHi dependence of a cation channel located in the apical membrane. This channel is selective for sodium over chloride but discriminates poorly between the monovalent cations Na+,K+,Li+ and Cs+. Its open probability (P(o)) rises at depolarising membrane potentials. Under normal conditions the channel is inactive in the cell-attached patch mode and is activated upon excision. However, after excision the channel usually runs down within 30-90 s which cannot be overcome by either altering the Ca(2+)-concentration (10(-3) mol/l, 10(-6) mol/l, Ca(2+)-free) or adding 1 mmol/l Mg-ATP to the bath solution. In the cell-attached patch mode the channel could be activated by decreasing pHi from pH 7.4 to pH 6.5, by either the ammonium prepulse technique or the nigericin K+ method, in more than 50% of the experiments performed. In the renal proximal tubule such a non-selective cation channel would constitute a functional Na+ channel and might therefore support Na+ reabsorption especially during the intracellular acidification due to hormonal inhibition of the Na+/H+ exchanger.


Subject(s)
Intracellular Fluid/metabolism , Ion Channels/metabolism , Kidney Tubules, Proximal/metabolism , Animals , Cell Line , Chloride Channels/metabolism , Hydrogen-Ion Concentration , Ion Channel Gating , Kidney Tubules, Proximal/cytology , Membrane Potentials , Opossums , Patch-Clamp Techniques , Sodium Channels/metabolism
7.
Ren Physiol Biochem ; 18(4): 191-7, 1995.
Article in English | MEDLINE | ID: mdl-7481070

ABSTRACT

We investigated the last step of mercapturic acid formation, the N-acetylation of cysteine S-conjugates, in the established opossum kidney (OK) cell line which exhibits characteristics of the proximal tubule. S-Benzyl-L-cysteine was used as a model substance for such a cysteine S-conjugate. We succeeded in showing that OK cells absorb S-benzyl-L-cysteine via an active transport system which is inhibitable by phenylalanine. This transport follows Michaelis-Menten kinetics and the two characterizing parameters were determined: the Michaelis-Menten constant Km = 1.8 mmol/l, and the maximum of the difference between the intracellular and the extracellular concentration of S-benzyl-L-cysteine delta Cmax = 19.4 mmol/l. S-Benzyl-L-cysteine is converted to N-acetyl-S-benzyl-L-cysteine at a constant rate, which is independent of the extracellular S-benzyl-L-cysteine concentration. Under the tested experimental conditions this is probably due to saturation of the microsomal N-acetyltransferase catalyzing this reaction. In conclusion, we have shown that OK cells are a suitable model for studying mercapturate formation. They take up S-benzyl-L-cysteine mainly via the same carrier as phenylalanine, which is known to be transported in the rat by the high-capacity, low-affinity neutral amino acid carrier, and convert it to N-acetyl-L-benzyl-S-cysteine.


Subject(s)
Acetylcysteine/metabolism , Arylamine N-Acetyltransferase/metabolism , Cysteine/analogs & derivatives , Free Radical Scavengers/metabolism , Kidney Tubules, Proximal/metabolism , Acetylation , Animals , Cell Line , Cysteine/pharmacokinetics , Extracellular Space/metabolism , Intracellular Fluid/metabolism , Ion Transport , Kidney Tubules, Proximal/drug effects , Opossums
8.
Otolaryngol Clin North Am ; 27(3): 487-510, 1994 Jun.
Article in English | MEDLINE | ID: mdl-8065755

ABSTRACT

This article reviews current literature in the areas of otoacoustic emissions and auditory brain stem responses (ABRs) and their application to the evaluation of peripheral auditory function in infants and children. The different types of otoacoustic emissions are described along with their incidence, development, clinical applications, and interpretation in the pediatric group. The development of the auditory system, reflected by ABRs, is presented in detail with previously unpublished results from three-channel Lissajous' trajectory studies performed in infants. Clinical application of frequency-specific ABRs, both air and bone conducted, are presented. Finally, a discussion of the need to develop objective estimators of signal quality and threshold detection for otoacoustic emissions and ABRs in infants and children is presented, which includes previously unpublished results evaluating a new technique.


Subject(s)
Hearing Disorders/diagnosis , Hearing Tests , Auditory Perception/physiology , Auditory Threshold/physiology , Child , Cochlea/physiology , Evoked Potentials, Auditory/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Humans , Infant
9.
Hear Res ; 72(1-2): 99-107, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8150750

ABSTRACT

Reported are the results of analyses of three-channel Lissajous trajectories (3CLTs) of the auditory brain stem responses (ABRs) in a human subject in whom a focal lesion of the brain stem was caused by stereotactic radiosurgery, the 'gamma knife'. The surgery caused total destruction of the right inferior colliculus. The results, using multiple measures for defining ABR components, confirm findings from more conventional 2-channel recordings which, in turn, suggested the presence of an intact wave IV but a negligible, if not totally absent, wave V with stimulation of the left (contralateral) ear. The results thus support theories that wave V is generated by crossed pathways and that wave IV is an independent wave generated by the lateral lemniscus. Since magnetic resonance imaging suggested no destruction of tissue below the inferior colliculus, the findings also support theories of wave V generation at or rostral to the inferior colliculus. In practical terms, the results demonstrate the value of multichannel recordings of the ABR in component identification and in interpreting ABR abnormalities.


Subject(s)
Brain/surgery , Evoked Potentials, Auditory, Brain Stem , Inferior Colliculi/injuries , Radiosurgery/adverse effects , Adult , Arteriovenous Malformations/surgery , Female , Humans , Inferior Colliculi/physiology , Magnetic Resonance Imaging
10.
Am J Otol ; 14(4): 362-8, 1993 Jul.
Article in English | MEDLINE | ID: mdl-8238273

ABSTRACT

To preserve hearing during vestibular neurectomy and acoustic neuroma removal, the cochlear nerve must be identified. Present techniques, including monitoring eighth nerve action potentials, help the surgeon identify those maneuvers that increase the risk of nerve injury but do not help in the anatomic identification of the cochlear nerve or the cochlear-vestibular cleavage plane. The purpose of this study was to demonstrate an electrophysiologic method of identifying the cochlear portion of the eighth cranial nerve. A flush-tipped, bipolar electrode recording probe was used to directly record responses to monaural click stimuli from the cochlear nerve but not from surrounding tissue. It was also used to delineate the cochlear-vestibular cleavage plane. Stimulus intensity levels over 25 dB sensation level tended to reduce the accuracy of nerve identification, and lower levels prolonged recording time. This technique and its application to posterior fossa surgery is discussed.


Subject(s)
Cholesteatoma/pathology , Cholesteatoma/surgery , Endoscopy , Mastoid/surgery , Adolescent , Adult , Aged , Cholesteatoma/diagnosis , Ear Canal/surgery , Female , Humans , Male , Middle Aged , Postoperative Complications
11.
Laryngoscope ; 103(6): 600-4, 1993 Jun.
Article in English | MEDLINE | ID: mdl-8502092

ABSTRACT

The purpose of this study was to measure, in the cat, spontaneous auditory nerve (AN) activity before and after injection with sodium salicylate. Ten cats were anesthetized, and the AN and round window (RW) were surgically exposed. Electrodes were applied to allow recording from three channels, including bipolar electrodes and monopolar electrodes located directly on the auditory nerve, in addition to an RW electrode. Spectral averaging of the spontaneous activity was performed before and during salicylate treatment. An increase in spectral activity near 200 Hz was noted in all cats by 3 hours after salicylate injection. This activity was present in bipolar, monopolar, and RW records, and was temporarily diminished or eliminated by injection of lidocaine. No such spectral changes were found in saline-injected control animals. These results show promise of developing a noninvasive, objective, quantitative measure of tinnitus for studies in animals and in man.


Subject(s)
Sodium Salicylate/pharmacology , Vestibulocochlear Nerve/drug effects , Vestibulocochlear Nerve/physiology , Animals , Cats , Disease Models, Animal , Electrophysiology , Evoked Potentials, Auditory, Brain Stem/drug effects , Fourier Analysis , Signal Processing, Computer-Assisted , Tinnitus/physiopathology
12.
Article in English | MEDLINE | ID: mdl-1382954

ABSTRACT

Conventional, vertex-ipsilateral ear records ('A'), as well as 3-channel Lissajous' trajectories (3-CLTs) of auditory brain-stem evoked potentials (ABEPs) were recorded from the scalp simultaneously with tympanic membrane electrocochleograms ('TME') and auditory nerve compound action potentials ('8-AP') recorded intracranially using a wick electrode on the auditory nerve between the internal auditory meatus and the brain-stem. The recordings were made during surgical procedures exposing the auditory nerve. The peak latency recorded from 'TME' corresponded to trajectory amplitude peak 'a' of 3-CLT and to peak 'I' of the 'A' channel ABEP. Peak latency of '8-AP' was slightly longer than the latency of peak 'II' of 'A' when '8-AP' was recorded from the root entry zone and the same or shorter when recorded from the nerve trunk. '8-AP' peak latency was shorter than trajectory amplitude peak 'b' of 3-CLT regardless of where the wick electrode was along the nerve. Peak latencies from all recording sites clustered into two distinct groups--those that included N1 from 'TME,' peak 'I' of the 'A' record and trajectory amplitude peak 'a' of 3-CLT, and those that included the negative peak of '8-AP' and trajectory amplitude peak 'b' of 3-CLT, as well as peak 'II' of the 'A' record, when present. In one case, the latency of peak 'II' and trajectory amplitude peak 'b' was manipulated by changing the conductive properties of the medium surrounding the auditory nerve.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Brain/physiology , Cochlea/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Scalp/physiology , Vestibulocochlear Nerve/physiology , Acoustic Stimulation , Action Potentials/physiology , Audiometry, Evoked Response , Electroencephalography , Electrophysiology/methods , Humans , Reaction Time/physiology , Time Factors
13.
Electroencephalogr Clin Neurophysiol ; 83(2): 153-61, 1992 Aug.
Article in English | MEDLINE | ID: mdl-1378381

ABSTRACT

Auditory brain-stem evoked potentials (ABEPs) were recorded during surgical procedures which exposed the cerebello-pontine angle (CPA) in humans. Recordings made with the CPA contralateral to stimulus exposed were compared with those obtained with the skin sutured at the end of surgery. Single-channel as well as 3-channel Lissajous' trajectory (3-CLT) analyses were used to evaluate the effect of the surgical exposure on ABEP. The results suggest that exposure of the CPA contralateral to the stimulated ear did not affect dipole equivalent orientation nor magnitude, but did affect timing of the recorded activity being more pronounced for segments 'd'-'e' (corresponding to waves IV-V) than for 'a'-'b' (waves I-II). The results imply that the effects of disrupting the volume conductor may have been overwhelmed by other effects, such as local temperature changes. These changes, although not associated with clinical sequella, should be accounted for when analyzing subtle quantitative changes involving surgical exposures.


Subject(s)
Cerebellopontine Angle/surgery , Evoked Potentials, Auditory, Brain Stem/physiology , Acoustic Stimulation , Adult , Cerebellopontine Angle/physiopathology , Electroencephalography , Female , Functional Laterality , Humans , Male , Reaction Time/physiology
14.
Life Sci ; 50(20): 1503-10, 1992.
Article in English | MEDLINE | ID: mdl-1579045

ABSTRACT

A comparison of the burdening effects on the reticulo-endothelial system (RES) by soybean oil emulsions with two different emulsifiers [soybean lecithin (SOB) and egg lecithin (EGG)] or by a perfluorochemical emulsion (Fluosol-DAR, PFC) was performed using a magnetometric method. This method is based on measuring the relaxation of injected iron oxide (gamma-Fe2O3) above the liver after magnetization in a strong external magnetic field. Three different methods of evaluation of the data were chosen. First, according to the conventional monoexponential function, second, according to a monoexponential function with a constant, and third, using the ratio of the initial dynamic to total magnetic field strength. In contrast to SOB and EGG, the PFC emulsion which was used depressed the RES-capacity to less than 31% of the control values (p less than 0.001). Following the administration of SOB the phagosomal motion was significantly lowered after 6 h (p less than 0.01) and 1-2 days (p less than 0.05); thereafter no significant difference of the relaxation constants remained as compared to the control group. The fatty emulsion with egg lecithin showed no significant lowering of the RES-capacity during the entire observation period (p greater than 0.05). Our results indicate that the RES-capacity is diminished not only by a PFC emulsion, but also temporarily by a soybean lecithin emulsion, though not by an egg lecithin emulsion, when given in the same dosages.


Subject(s)
Lipids/pharmacology , Liver/drug effects , Magnetics , Mononuclear Phagocyte System/drug effects , Animals , Liver/metabolism , Male , Mononuclear Phagocyte System/metabolism , Rats , Rats, Inbred Strains
15.
Pflugers Arch ; 418(4): 383-92, 1991 May.
Article in English | MEDLINE | ID: mdl-1652125

ABSTRACT

The accumulation of fluorescein (FITC)-labelled bovine albumin was measured against the extracellular-fluid-phase marker FITC-inulin within confluent monolayers of the opossum kidney cell line OK. Fluorescence and electron microscopic pictures show that FITC-albumin is taken up by endocytosis and appears in a vesicular intracellular distribution. The uptake of FITC-albumin was quantified by measuring the cell-adherent fluorescence fluorimetrically. FITC-albumin uptake shows a time- and concentration-dependent saturation kinetics in contrast to the non-saturable FITC-inulin uptake, and exceeds the latter more than tenfold at low concentrations. Half-maximum saturation occurs at 20-30 mg/l. Initial FITC-albumin uptake/mg protein is stimulated by cell maturation, being six-to sevenfold higher in the confluent than in the subconfluent state, while FITC-inulin uptake is unchanged. Both an elevation of ambient osmolality to 600-750 mOsm/kg and disruption of the cytoskeleton by cytochalasin B (0.1 mmol/l) reduce initial FITC-albumin uptake by 50%-60% in a non-additive fashion. Albumin endocytosis is reduced both in acidic (pH 5.4) and alkaline (pH 8.4) medium, but does not depend on extracellular sodium, calcium or chloride. High concentrations of fetal calf serum or unlabelled albumin reduce FITC-albumin endocytosis dose-dependently. The present study is the first to investigate both the protein uptake and the fluid-phase endocytosis in a cultured proximal tubular cell line, using these cells as a model system-for proximal tubular protein reabsorption.


Subject(s)
Albumins/pharmacokinetics , Endocytosis/physiology , Kidney Tubules, Proximal/cytology , Opossums/physiology , Receptors, Cell Surface/physiology , Albumins/metabolism , Animals , Cells, Cultured , Cytoskeleton/physiology , Cytoskeleton/ultrastructure , Epithelial Cells , Epithelium/metabolism , Epithelium/physiology , Fluorescein-5-isothiocyanate , Fluoresceins , Hydrogen-Ion Concentration , Insulin/metabolism , Insulin/pharmacokinetics , Kidney Tubules, Proximal/metabolism , Kidney Tubules, Proximal/physiology , Microscopy, Electron , Microscopy, Fluorescence/methods , Opossums/metabolism , Osmolar Concentration , Thiocyanates , Time Factors
16.
Pflugers Arch ; 417(5): 523-7, 1991 Jan.
Article in English | MEDLINE | ID: mdl-2011474

ABSTRACT

We investigated the capacity and the localization of N-acetylation of the mercapturic acid precursor S-benzyl-L-cysteine (BC), as well as the tubular reabsorption of this compound in the rat kidney in vivo et situ by renal clearance and continuous microinfusion and microperfusion experiments. In renal clearance experiments. 450 mumol BC was infused intravenously for 180 min. During the time of BC infusion and the following 180 min, the two kidneys excreted 400 mumol or 90% of the infused BC dose as the mercapturate N-acetyl-S-benzyl-L-cysteine (AcBC). Comparison of the amounts of BC and AcBC entering the left kidney via the renal artery with those leaving it via the renal vein and the ureter showed that 0.13 +/- 0.04 mumol BC/min (mean +/- SEM) was extracted and 0.24 +/- 0.08 mumol AcBC/min was formed by one kidney. The intrarenal acetylation can account for the formation of 38% of the mercapturate excreted in the final urine. In additional experiments, 50 pmol/min [14C]BC was microinfused into single superficial tubules at three different sites. During microinfusion into early proximal tubules, the final urine contained 16.3 +/- 1.8% of the microinfused radioactivity as AcBC, but no BC. When [14C]BC was microinfused into late proximal tubules, 13.0 +/- 2.3% of the infused label was recovered as BC, 28.1 +/- 2.3% as AcBC. During microinfusion into early distal tubules, the final urine contained no AcBC, but 90.3 +/- 2.1% of the infused [14C]BC was recovered.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Acetylcysteine/metabolism , Cysteine/analogs & derivatives , Kidney/metabolism , Acetylation , Animals , Cysteine/metabolism , Male , Metabolic Clearance Rate , Perfusion , Rats , Rats, Inbred Strains
18.
J Membr Biol ; 117(3): 243-51, 1990 Sep.
Article in English | MEDLINE | ID: mdl-2172545

ABSTRACT

Confluent monolayers of the established opossum kidney cell line were exposed to NH4Cl pulses (20 mmol/liter) during continuous intracellular measurements of pH, membrane potential (PDm) and membrane resistance (R'm) in bicarbonate-free Ringer. The removal of extracellular NH4Cl leads to an intracellular acidification from a control value of 7.33 +/- 0.08 to 6.47 +/- 0.03 (n = 7). This inhibits the absolute K conductance (gK+), reflected by a decrease of K+ transference number from 71 +/- 3% (n = 28) to 26 +/- 6% (n = 5), a 2.6 +/- 0.2-fold rise of R'm, and a depolarization by 24.2 +/- 1.5 mV (n = 52). In contrast, intracellular acidification during a block of gK+ by 3 mmol/liter BaCl2 enhances the total membrane conductance, being shown by R'm decrease to 68 +/- 7% of control and cell membrane depolarization by 9.8 +/- 2.8 mV (n = 17). Conversely, intracellular alkalinization under barium elevates R'm and hyperpolarizes PDm. The replacement of extracellular sodium by choline in the presence of BaCl2 significantly hyperpolarizes PDm and increases R'm, indicating the presence of a sodium conductance. This conductance is not inhibited by 10(-4) mol/liter amiloride (n = 7). Patch-clamp studies at the apical membrane (excised inside-out configuration) revealed two Na(+)-conductive channels with 18.8 +/- 1.4 pS (n = 10) and 146 pS single-channel conductance. Both channels are inwardly rectifying and highly selective towards Cl-. The low-conductive channel is 4.8 times more permeable for Na+ than for K+. Its open probability rises at depolarizing potentials and is dependent on the pH of the membrane inside (higher at pH 6.5 than at pH 7.8).


Subject(s)
Kidney Tubules, Proximal/metabolism , Potassium Channels/metabolism , Sodium Channels/metabolism , Animals , Cells, Cultured , Electric Conductivity , Homeostasis , Hydrogen-Ion Concentration , Kidney Tubules, Proximal/cytology , Membrane Potentials , Models, Biological , Opossums , Potassium/metabolism , Sodium/metabolism
20.
FEBS Lett ; 269(1): 226-8, 1990 Aug 20.
Article in English | MEDLINE | ID: mdl-2117554

ABSTRACT

Chronic exposure (24 h) to parathyroid hormone (PTH) increases the intracellular proteolytic activity in cultured opossum kidney cells 2-fold at physiological PTH concentrations (10(-12) mol/l). This increase can be blocked by E-64, an inhibitor of thiol proteinases. The phorbol ester TPA mimicks the effect of PTH, whereas the calcium ionophore A23187 reduces the intracellular proteinase activity. Forskolin and dibutyrylic cAMP do not elevate proteinase activity. The protein kinase C inhibitor staurosporine is equally effective in blocking the TPA- and PTH-induced proteinase activity increase. These data indicate that PTH increases the intracellular thiol proteinase activity by an activation of protein kinase C and not by the cAMP dependent way.


Subject(s)
Cysteine Endopeptidases/metabolism , Kidney Tubules/enzymology , Parathyroid Hormone/pharmacology , Protein Kinase C/metabolism , Animals , Calcimycin/pharmacology , Cell Line , Cysteine Proteinase Inhibitors , Enzyme Activation/drug effects , In Vitro Techniques , Leucine/analogs & derivatives , Leucine/pharmacology , Opossums , Peptide Hydrolases/metabolism , Tetradecanoylphorbol Acetate/pharmacology
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