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The clinical relevance of human lungtissue adrenoceptor characterization
295 THE CLINICAL RELEVANCE OF HUMAN LUNGTISSUE ADRENOCEPTOR CHARACTERIZATION.
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J.A.M. Raaijmakers, G.K. T e r p s t r a , G.A. Wassink and J. K r e u k n i e t . Dept. o f Pulmonary Diseases, Academic H o s p i t a l , U t r e c h t , The Netherlands. Adrenoceptor ( s u b - ) p o p u l a t i o n s can nowadays very w e l l be determined in a l l kinds o f t i s s u e by using r a d i o ] i g a n d b i n d i n g s t u d i e s . In t h i s way i t a l s o became p o s s i b l e to i n v e s t i g a t e the a d r e n e r g i c d e f e c t , as is proposed in asthma by S z e n t i v a n y i , a t the l e v e l o f the recept o r i t s e l f . With t h i s i n t e n t i o n we c h a r a c t e r i z e d adrenoceptor p o p u l a t i o n s in specimens o f human ] u n g t i s s u e , o b t a i n e d at thoracotomy of normal i n d l v t d u a I s and CNSLD ( c h r o n i c non s p e c i f i c lung diseases) p a t i e n t s . In CNSLD p a t i e n t s we found the number o f oC-adrenoceptors to be markedly enhanced (Bmax values 1886 + 369 vs 400 + 52 fM/mg p r o t e i n ) , w h i l e t h e p e r centage o f r ~ 2 - a d r e n o c e p t o r s is decreased ~28t + 3.2 vs--63 ~ 2.7 in n o r m a l s ) . Tne r e s u l t s o f these b i n d i n g s t u d i e s , e s p e c i a l ] ~ those concerning t h e ~ - a d r e n o c e p t o r can be c o r r e l a t e d w i t h pulmonary f u n c t i o n . Furthermore i t appeared p o s s i b l e t o modulate adrenoceptor c h a r a c t e r i s t i c s in v i t r o w i t h cromoglycate and k e t o t i f e n . This r e v e a l s therapeutlca] possibilities f o r these substances, based on o t h e r pharmacological mechanisms than h i t h e r t o have been assumed. These f i n d i n g s may c o n t r i b u t e to a deeper understanding o f the p h y s i o l o g i c a l and c l i n i c a l meaning of a d r e n o c e p t o r c h a r a c t e r i s t i c s in human l u n g t i s s u e .
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H A R A C T E R I Z A T I O N O F MEMBRANE HISTAMINE R E C E P T O R S BY H | - M E P Y R A M I N E BINDING Marina C a r m a n - K r ~ a n
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Dept. P h a r m a c o l o g y , M e d i c a l F a c u l t y , V r a z o v t r g 2, 61000 L j u b l j a n a , Y u g o s l a v i a 3H] m e p y r a m i n e has b e e n used a s a s e l e c t i v e l i g a n d for l a b e l i n g h i s t a m i n e H 1 r e c e p t o r s in d i f f e r e n t t i s s u e s . In the v a s c u l a r s m o o t h m u s c l e m e m b r a n e (beef a d r t a ) the a n t a g o n i s t - s e n s i t i v e b i n d i n g of [ " H ] m e p y r a m i n e was a s e x p e c t e d for b i n d i n g to H. r e c e p t o r s . The m a x z m a l H 1 r e c e p t o r b i n d i n g c a p a c i t y was 140 - 20 f m o l / m g 1 m e m b r a n e p r o t e i n , and the d i s s o c i a t i o n c o n s t a n t d e r i v e d f r o m the S c a t c h a r d plot 6 nM. The c h a r a c t e r i s t i c s of a g o n i s t a n d a n t a g o n i s t i n h i b i t i o n o f [ 3 H ] m e p y r a m i n e b i n d i n g (conc. 5 nM) w e r e those e x p e c t e d for H 1 r e c e p t o r a n d a r e in good a g r e e m e n t with the c h a r a c t e r i s t i c s d e t e r m i n e d by the p h a r m a c o l o g i c e x p e r i m e n t s . •
A HEPTAPEPTIDE
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SEGMENT OF B2-MICROGLOBULIN ACTIVITY IN NORMAL AND UREMIC PATIENTS.
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"4"
INDUCES CYTOTOXIC AND SUPPRESSOR CELL
J~ayPleszczvnstci. $. Forand. D. Bolduc. and S. St-Pierre, Departments of Pediatrics and Pharmacology, Facult~ de M~declne, Univ. de Sherbrooke, Quebec, Canada. A heptapeptide fragment of B 2 - m l c r o g l o b u l i n has been described by Abiko in hemodialysates of uremic patients and found to inhibit E-rosette formation by human T cells. In order to study the possible immunoregulatcry effects of this heptapeptide, we investigated its potential for induction of cytotoxlc and suppressor cells. Low concentrations (0.072 - 0.36 ug/ml) enhanced cytotoxic activity of human lymphocytes against herpes simplex vlrus-infected cells by 50-60~ whereas hlgher concentrations (36-360 ug/~d) depressed cytotoxicity. When lymphccytes were incubated with the heptapeptide during an in-vitro sensitization assay, similar biphasic effects were found. The same low concentrations also induced the appearance of suppressor cells during a 24 h preincubation before addition to lymphocyte cultures stimulated with HSV antigen. Although most uremic patients responded in a similar fashion, q/12 patients failed to show any enhanced cytotoxlc or suppressor activity in the presence of the heptapeptide. We suggest that high concentrations of this peptide may play a role in the abnormal cellular immune function in uremia. Supported by the Kidney Foundation and MRC.
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J.A.M. Raaijmakers, G.K. T e r p s t r a , G.A. Wassink and J. K r e u k n i e t . Dept. o f Pulmonary Diseases, Academic H o s p i t a l , U t r e c h t , The Netherlands. Adrenoceptor ( s u b - ) p o p u l a t i o n s can nowadays very w e l l be determined in a l l kinds o f t i s s u e by using r a d i o ] i g a n d b i n d i n g s t u d i e s . In t h i s way i t a l s o became p o s s i b l e to i n v e s t i g a t e the a d r e n e r g i c d e f e c t , as is proposed in asthma by S z e n t i v a n y i , a t the l e v e l o f the recept o r i t s e l f . With t h i s i n t e n t i o n we c h a r a c t e r i z e d adrenoceptor p o p u l a t i o n s in specimens o f human ] u n g t i s s u e , o b t a i n e d at thoracotomy of normal i n d l v t d u a I s and CNSLD ( c h r o n i c non s p e c i f i c lung diseases) p a t i e n t s . In CNSLD p a t i e n t s we found the number o f oC-adrenoceptors to be markedly enhanced (Bmax values 1886 + 369 vs 400 + 52 fM/mg p r o t e i n ) , w h i l e t h e p e r centage o f r ~ 2 - a d r e n o c e p t o r s is decreased ~28t + 3.2 vs--63 ~ 2.7 in n o r m a l s ) . Tne r e s u l t s o f these b i n d i n g s t u d i e s , e s p e c i a l ] ~ those concerning t h e ~ - a d r e n o c e p t o r can be c o r r e l a t e d w i t h pulmonary f u n c t i o n . Furthermore i t appeared p o s s i b l e t o modulate adrenoceptor c h a r a c t e r i s t i c s in v i t r o w i t h cromoglycate and k e t o t i f e n . This r e v e a l s therapeutlca] possibilities f o r these substances, based on o t h e r pharmacological mechanisms than h i t h e r t o have been assumed. These f i n d i n g s may c o n t r i b u t e to a deeper understanding o f the p h y s i o l o g i c a l and c l i n i c a l meaning of a d r e n o c e p t o r c h a r a c t e r i s t i c s in human l u n g t i s s u e .
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H A R A C T E R I Z A T I O N O F MEMBRANE HISTAMINE R E C E P T O R S BY H | - M E P Y R A M I N E BINDING Marina C a r m a n - K r ~ a n
51
Dept. P h a r m a c o l o g y , M e d i c a l F a c u l t y , V r a z o v t r g 2, 61000 L j u b l j a n a , Y u g o s l a v i a 3H] m e p y r a m i n e has b e e n used a s a s e l e c t i v e l i g a n d for l a b e l i n g h i s t a m i n e H 1 r e c e p t o r s in d i f f e r e n t t i s s u e s . In the v a s c u l a r s m o o t h m u s c l e m e m b r a n e (beef a d r t a ) the a n t a g o n i s t - s e n s i t i v e b i n d i n g of [ " H ] m e p y r a m i n e was a s e x p e c t e d for b i n d i n g to H. r e c e p t o r s . The m a x z m a l H 1 r e c e p t o r b i n d i n g c a p a c i t y was 140 - 20 f m o l / m g 1 m e m b r a n e p r o t e i n , and the d i s s o c i a t i o n c o n s t a n t d e r i v e d f r o m the S c a t c h a r d plot 6 nM. The c h a r a c t e r i s t i c s of a g o n i s t a n d a n t a g o n i s t i n h i b i t i o n o f [ 3 H ] m e p y r a m i n e b i n d i n g (conc. 5 nM) w e r e those e x p e c t e d for H 1 r e c e p t o r a n d a r e in good a g r e e m e n t with the c h a r a c t e r i s t i c s d e t e r m i n e d by the p h a r m a c o l o g i c e x p e r i m e n t s . •
A HEPTAPEPTIDE
.
SEGMENT OF B2-MICROGLOBULIN ACTIVITY IN NORMAL AND UREMIC PATIENTS.
.
"4"
INDUCES CYTOTOXIC AND SUPPRESSOR CELL
J~ayPleszczvnstci. $. Forand. D. Bolduc. and S. St-Pierre, Departments of Pediatrics and Pharmacology, Facult~ de M~declne, Univ. de Sherbrooke, Quebec, Canada. A heptapeptide fragment of B 2 - m l c r o g l o b u l i n has been described by Abiko in hemodialysates of uremic patients and found to inhibit E-rosette formation by human T cells. In order to study the possible immunoregulatcry effects of this heptapeptide, we investigated its potential for induction of cytotoxlc and suppressor cells. Low concentrations (0.072 - 0.36 ug/ml) enhanced cytotoxic activity of human lymphocytes against herpes simplex vlrus-infected cells by 50-60~ whereas hlgher concentrations (36-360 ug/~d) depressed cytotoxicity. When lymphccytes were incubated with the heptapeptide during an in-vitro sensitization assay, similar biphasic effects were found. The same low concentrations also induced the appearance of suppressor cells during a 24 h preincubation before addition to lymphocyte cultures stimulated with HSV antigen. Although most uremic patients responded in a similar fashion, q/12 patients failed to show any enhanced cytotoxlc or suppressor activity in the presence of the heptapeptide. We suggest that high concentrations of this peptide may play a role in the abnormal cellular immune function in uremia. Supported by the Kidney Foundation and MRC.
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