Differences between the effects of thyroxine and tetraiodothyroacetic acid on TSH suppression and cardiac hypertrophy

OBJECTIVE

We earlier reported marked qualitative differences between the effect of 3,5,3'-tri-iodothyroacetic acid (Triac) and tri-iodothyronine (T3) on cardiac hypertrophy at equivalent thyroid-stimulating hormone (TSH)-suppressive doses. We have now extended these studies to specific cardiac parameters. Due to its rapid metabolic clearance rate, Triac is not suitable for TSH suppression and therefore the slowly metabolized 3,5,3',5'-tetraiodothyroacetic acid (Tetrac), the precursor of Triac, was studied.

METHODS

Hypothyroid rats were infused over 13 days with 1.5-40.5 nmol Tetrac/day per 100 g body weight (BW) or with 0.5-13.5 nmol thyroxine ((4)T4)/day per 100 g BW.

RESULTS

The responses of serum TSH and of hepatic monodeiodinase type 1 were parallel for both hormones, their potency ratios could therefore be compared. Tetrac was revealed as being only half as active on hepatic monoiodinase type 1 despite a similar serum TSH levels. Tetrac can therefore be considered to have a preferential action on serum TSH suppression. The cardiac effects on Ca2+-ATPase (SERCA 2a) and monodeiodinase type 1 activity were qualitatively different and therefore one cannot give an overall quantitative estimate of these differences. The results showed clearly, however, that Tetrac is less efficient for all parameters studied, namely induction of cardiac hypertrophy, alpha-myosin heavy chain mRNA, monodeiodinase type 1 activity and mRNA levels of the sarcoplasmic SERCA 2a.

CONCLUSION

We postulate therefore that, in the rat and possibly in man, Tetrac could represent a favorable alternative for suppression of serum TSH levels.

[Comparison of Hannover Functional Ability Questionnaire (FFbH) and the SF-36 subscale "Physical Functioning"]

Pretesting of a questionnaire for evaluating day-patient rehabilitation, which included comparison of the "Hannover Functional Ability Questionnaire" (FFbH) and the SF-36 subscale "physical functioning" (SF-36 PF), gave rise to more extensive validity testing of the two instruments. In the framework of an expanded pretest, a questionnaire including FFbH and SF-36 PF was sent out to 520 adult former patients who had undergone inpatient orthopaedic rehabilitation following total hip or knee replacement an average 16 months ago. Return rate was 76%. Checks on plausibility showed no complaints about the Hannover Functional Ability Questionnaire while, on the SF-36 subscale, it was found that 16 of 374 patients (4.3%) had confused positive and negative ratings. Moreover, problems were found concerning the wording of several items (understanding, multidimensionality). In contrast to the FFbH, the SF-36 subscale shows weaknesses in the formulation of its items and particularly its ratings.

Synthesis of 8-(omega-Hydroxyalkyl)-, 8-(omega-hydroxyalk-1-enyl)-, and 8-(omega-hydroxyalk-1-ynyl)adenines using the tert-butyldimethylsilyloxymethyl group, a new and versatile protecting group of adenine

The synthesis of 12 analogues of adenine substituted at C-8 by an omega-hydroxyalkyl, omega-hydroxyalk-1-enyl, or omega-hydroxyalk-1-ynyl chain of various length has been carried out in five or six steps starting from adenine. The analogues were obtained using a new protecting group of adenine, the tert-butyldimethylsilyloxymethyl group. 9-tert-Butyldimethylsilyloxymethyl-adenine is more soluble than adenine in organic solvents. It was prepared regiospecificaly in two steps from adenine and was amenable to C-8 iodination under basic conditions and to subsequent introduction of the various carbon chains at C-8 by palladium-catalyzed cross-coupling reactions (Stille or Sonogashira). The protecting group was removed under acidic conditions, thus demonstrating its versatility.

Polymorphism of tedisamil dihydrochloride

The results of studies on tedisamil dihydrochloride in the solid state demonstrate that the compound occurs in three polymorphic forms. The three modifications have been characterized by thermomicroscopy, differential scanning calorimetry (DSC), vibrational spectroscopy, solid-state nuclear magnetic resonance (NMR), and X-ray powder diffractometry (XRPD). The thermodynamic relationships are illustrated in a semischematic energy/temperature diagram that gives information about the relative stability and physical properties of the three modifications between 0 K and the melting temperatures. The three modifications are enantiotropically related. Modification II, the material obtained during manufacturing, is the thermodynamically stable crystal form at 20 degrees C. The thermodynamic transition point of mod II with I (instant melting point: 248-250 degrees C) is between 100 and approximately 140 degrees C (DeltaH(t,II/I) = 4.4+/-0.8 kJ/mol (95% CI)). A phase transition of mod II (probably into mod III) was detected thermomicroscopically at about -180 degrees C. The thermodynamic transition point of mod III with I was determined to be at -9 to -6 degrees C. Because mods I and III are thermodynamically and kinetically unstable at ambient conditions, these crystal forms are of analytical interest.

Identification and characterization of the mre gene region of Streptomyces coelicolor A3(2)

During a search for new differentiation factors in Streptomyces coelicolor A3(2), a locus at 11 o'clock on the S. coelicolor map was identified which harbours several genes that show extensive similarity to cell division and differentiation genes from Escherichia coli and Bacillus subtilis. From the sequence data it was concluded that the region contains the genes mireB, mreC, mreD (murein formation gene cluster E), pbp83 (high-molecular-weight penicillin-binding protein) and sfr (member of the spoVE/ftsW/rodA family). Mre gene products are reported to be responsible for determining cell shape in E. coli and Bacillus. The S. coelicolor mreC gene was inactivated by gene disruption, resulting in mutants which showed significant growth retardation in comparison to the wild type. Inactivation of the mreB gene was incompatible with viability, and thus mreB represents a Streptomyces cell division gene that is essential for survival. Promoter-probe experiments led to the identification of an operon structure, with promoters located upstream of mreB, pbp83 and sfr. Detailed studies of mreB transcription revealed the existence of three promoters; two of them are constitutively transcribed, whereas the third is developmentally regulated.

(E)-1-alkyl-4-

(E)-1-Alkyl-4-[2-(alkylsulfonyl)-1-ethenyl]pyridinium salts were synthesized in two steps. These sulfones were stable at pH 7.3 and underwent a nucleophilic vinylic substitution (S(N)V) with mercaptans, including thiouracile, to give the corresponding 4-(thiovinyl)-pyridinium salts. The X-ray diffraction structure of (E)-1-methyl-4-[2-(ethylsulfanyl)-1-ethenyl]pyridinium iodide indicated conjugation of the sulfur with the pyridinium ring. (Z)-1-Methyl-4-[2-(methylsulfanyl)-1-ethenyl]pyridinium iodide, prepared from the corresponding thioether by reaction with methyl iodide in diethyl ether, underwent isomerization to the E isomer in a first-order reaction in deuterated [D6]DMSO with an activation energy of 14 kcalmol(-1). At pH 7, the (E)-1-methyl-4-[2-(methylsulfonyl)-1-ethenyl]pyridinium iodide (19) reacted specifically with thiols. The reaction of this sulfone with glutathione in a TES buffer at pH 7 was a second-order reaction (k = 4,100 M(-1)s(-1) at 30 degrees C) and gave the corresponding substitution product with an intense long wavelength absorption band (lambdamax=360 nm, epsilon = 27,500 M(-1)cm(-1)). The modification of different enzymes of known structure with 19 showed the high selectivity of this reagent towards thiol groups and its usefulness in the quantitative determination of free thiol groups in proteins.

[Pituitary necrosis after spinal anesthesia : a case report]

Spinal anesthesia was administered to a patient for the surgical reduction of an inguinal hernia. However, the procedure was complicated by corticotropic insufficiency secondary to the necrosis of a non-secretory hypophyseal adenoma. The clinical presentation is discussed here together with both medical and neurosurgical managements. Etiology and pathophysiological mechanisms of this complication are analyzed in accordance with the most recent of the literature.

Evaluation of the antitumor activity of 1-(3-C-ethynyl-beta-D-ribofuranosyl) (PJ272), a recent ribonucleoside analogue

The antiproliferative properties of a new ribonucleoside derivative, 1-(3'-C-ethynyl-beta-D-ribofuranosyl)uracil (PJ 272) that we synthesized a few years ago, were investigated in vitro on a variety of tumor cell lines from human and murine origins and in vivo, in tumor bearing mice. Using the 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we showed the ability of this compound to depress, at nanomolar concentrations, the growth of leukemia and lymphoma cultured cells. In 7 out of 8 tumor cell lines tested concentration of 50% inhibition (IC50) was found to be less than 25 nM. PJ 272 was also shown to present the same cytotoxicity against K562 Adriamycin-resistant cell line, which express a multi-drug resistance (MDR) phenotype, and its Adriamycin-sensitive parent cell line. Moreover, when injected intraperitoneally at 20 mg/kg every three days, PJ 272 was found to significantly increase the survival rate (T/C = 149%) of DBA/2 mice injected intraperitoneally with L1210 leukemic cells. Taken together, these results suggest that PJ 272 could be considered as a potentially very active drug against lymphoma and leukemia.

Energy/temperature diagram and compression behavior of the polymorphs of D-mannitol

Three modifications of D-mannitol were produced and investigated: mod. I (mp 166.5 degrees C, heat of fusion 53.5 kJ mol(-1)), mod. II (mp 166 degrees C, heat of fusion 52.1 kJ mol(-1)), and mod. III (mp incongruent 150-158 degrees C, heat of transition, III to I 0.2 kJ mol(-1)). The measured densities are 1.490 +/- 0.000 g cm(-3) [95% confidence interval (CI)] for mod. I, 1.468 +/- 0.002 g cm(-3) (95% CI) for mod. II, and 1.499 +/- 0.004 g cm(-3) (95% CI) for mod. III. It was possible to relate the different modifications given in the literature to one of the three pure crystal forms or to mixtures of two or all three modifications. The thermodynamic relationship among the crystal forms is represented in a semi-schematic energy/temperature diagram. From these data we can conclude that mod. III is thermodynamically stable at absolute zero. It is enantiotropically related to mod. I and mod. II. FTIR and Raman spectra, differential scanning calorimetry curves, and X-ray powder patterns of these crystal forms are depicted for doubtless assignment in the future. The water uptake of the three modifications at 92% relative humidity and 25 degrees C is less than 1%. The differences of the heat capacities and the heats of solution between mod. II and III are not significant, whereas mod. I shows small significant differences compared with the other modifications. In addition, compaction studies of these crystal forms were performed by means of an instrumented hydraulic press. The results show that mod. III should have the best tableting behavior under these conditions.

3'-Beta-ethynyl and 2'-deoxy-3'-beta-ethynyl adenosines: first 3'-beta-branched-adenosines substrates of adenosine deaminase

The 3'-C-branched-adenosine and 2'-deoxyadenosine analogues 1-7 were tested as substrate of adenosine deaminase. The 9-(3'-C-ethynyl-beta-D-ribo-pentofuranosyl)adenine 1 and its 2'-deoxy analogue 7 were deaminated by the enzyme while the vinyl and ethyl derivatives 2 and 3 were not. The 9-(3'-C-branched-beta-D-xylo-pentofuranosyl)adenines 4-6 were deaminated by the deaminase.

Polymorphism and preformulation studies of lifibrol

Three polymorphic modifications of lifibrol, a novel cholesterol-lowering drug substance, were detected and thoroughly investigated and characterized by thermomicroscopy, DSC, IR-spectroscopy and X-ray powder diffractometry. Mod. I (m.p. 142 degrees C) and mod. II (m.p. 135 degrees C) are stable. Furthermore, true densities, solubilities as function of temperature and pH-value as well as the behavior of the crystal forms under the influence of humid air were determined. The three modifications show distinct differences by IR-spectroscopy, through which a distinction even is possible. The density of mod. I is lower than that of mod. II. The transition of mod. II into mod. I corresponds to an endothermic reaction; from this it follows, that between mod. I and mod. II enantiotropism exists. Mod. II is at 20 degrees C by about 44% less soluble as mod. I. Mod. III, which only can be produced by crystallizing the glassy solidified melt, has a negative heat of transition. That means that mod. III behaves monotropic with regard to both enantiotropic modifications I and II. Mod. I exists in form of small lamellae, mostly of irregular forms. Mod. II consists of rhombohedron grains. Because of this difference in habit, for mod. II one can predict the best properties in case of pressing tablets.

Prospective evaluation of autonomic dysfunction in aggressive management of diabetic microangiopathy

Twenty-six type I diabetic nephropathy patients in a rigorous schedule for glucose control to preserve kidney function were studied to determine autonomic functional changes during 18 months. Intercurrent and nonrelated acute illness, withdrawal from the study for personal reasons, or failure to undergo testing on schedule resulted in complete data at 1 year for 26 of the original 41 patients enrolled, 24 patients completing a further 6 months. Glycohemoglobin A1c dropped for the total group from 9.0 to 7.9 at 6 months, 8.0 at 12 months, and 8.1 at 18 months (P<.01). Autonomic function tests revealed baseline results that were below the anticipated normals for age in 38% to 56% of patients. Timed ventilatory heart rate variations measured for the total group were 1.11, 1.13, 1.10, and 1.09 (normal > or =1.20). Valsalva heart rate variations for the total group were 1.27, 1.30, 1.255, and 1.35 (normal > or =1.50). Assumption of upright posture-related heart rate variations for the total group were 1.10, 1.07, 1.07, and 1.06 (normal > or =1.20). Mean arterial pressure day/night ratios for the total group were 1.04, 1.05, 1.05, and 1.08 (normal > or =1.10). Group analysis based on differences in insulin treatment programs, levels of blood pressure, and levels of renal function revealed no significant differences from the total group or companion groups during 18 months. Patients with a glycohemoglobin A1c of <8.0% were more likely to normalize mean arterial pressure day/night ratios than those with glycohemoglobin A1c > or =8.0%. We conclude that aggressive glucose control in diabetic patients with proteinuria for a period of 18 months resulted in a reproducible pattern of autonomic function tests during that period of time with neither worsening nor improvement. The restoration of day/night mean arterial pressure variation in a minority of patients should be studied with a larger cohort.

An evaluation of the transition temperature range of super-elastic orthodontic NiTi springs using differential scanning calorimetry

Differential scanning calorimetry (DSC) was used to determine the transition temperature ranges (TTR) of four types of super-elastic orthodontic nickel-titanium coil springs (Sentalloy). A knowledge of the TTR provides information on the temperature at which a NiTi wire or spring can assume superelastic properties and when this quality disappears. The spring types in this study can be distinguished from each other by their characteristic TTR during cooling and heating. For each tested spring type a characteristic TTR during heating (austenite transformation) and cooling (martensite transformation) was evaluated. The hysteresis of the transition temperature, found between cooling and heating, was 3.4-5.2 K. Depending on the spring type the austenite transformation started (As) at 9.7-17.1 degrees C and finished (Af) at 29.2-37 degrees C. The martensite transformation starting temperature (Ms) was evaluated at 32.6-25.4 degrees C, while Mf (martensite transformation finishing temperature) was 12.7-6.5 degrees C. The results show that the springs become super-elastic when the temperature increases and As is reached. They undergo a loss of super-elastic properties and a rapid decrease in force delivery when they are cooled to Mf. For the tested springs, Mf and As were found to be below room temperature. Thus, at room temperature and some degrees lower, all the tested springs exert super-elastic properties. For orthodontic treatment this means the maintenance of super-elastic behaviour, even when mouth temperature decreases to about room temperature as can occur, for example, during meals.

Sympathomimetic effects of MIBG: comparison with tyramine

Because nothing is known about whether metaiodobenzylguanidine (MIBG) has tyramine-like actions, the sympathomimetic effects of MIBG were determined in the isolated rabbit heart and compared with those of tyramine.

METHODS

Spontaneously beating rabbit hearts were perfused with Tyrode's solution (Langendorff technique; 37 degrees C; 26 mL/min), and the heart rate as well as the norepinephrine and dopamine overflow into the perfusate was measured before and after doses of MIBG or tyramine (0.03-10 micromol) given as bolus injections (100 microL) into the aortic cannula. Km and Vmax values for the neuronal uptake (uptake1) of 125I-MIBG and 14C-tyramine were obtained in human neuroblastoma (SK-N-SH) cells. The Ki of MIBG for inhibition of the 3H-catecholamine uptake mediated by the vesicular monoamine transporter was determined in membrane vesicles obtained from bovine chromaffin granules and compared with the previously reported Ki value for tyramine determined under identical experimental conditions.

RESULTS

By producing increases in heart rate and norepinephrine overflow, both compounds had dose-dependent sympathomimetic effects in the rabbit heart. MIBG was much less effective than tyramine in increasing heart rate (maximum effect 59 versus 156 beats/min) and norepinephrine overflow (maximum effect 35 versus 218 pmol/g). Tyramine also caused increases in dopamine overflow, whereas MIBG was a poor dopamine releaser. At a dose of 10 micromol, the increase in heart rate lasted more than 60 min after MIBG and about 20 min after tyramine injection. Accordingly, the norepinephrine overflow caused by 10 micromol MIBG and tyramine declined with half-lives of 57.8 and 2.2 min, respectively. The effects of both drugs were drastically reduced in hearts exposed to 2 micromol/L desipramine. The kinetic parameters characterizing the saturation of neuronal uptake by 125I-MIBG and 14C-tyramine were similar for the two compounds: Km values of MIBG and tyramine were 1.6 and 1.7 micromol/L, respectively, and Vmax values of MIBG and tyramine were 43 and 37 pmol/mg protein/min, respectively. However, in inhibiting the vesicular 3H-catecholamine uptake, MIBG was eight times less potent than tyramine.

CONCLUSION

MIBG is much less effective than tyramine as an indirect sympathomimetic agent. This is probably a result of its relatively low affinity for the vesicular monoamine transporter and explains the relatively poor ability of the drug to mobilize norepinephrine stored in synaptic vesicles. The long duration of MIBG action results primarily from the drug not being metabolized by monoamine oxidase. The sympathomimetic effects of MIBG described here are not likely to come into play in patients given diagnostic or common therapeutic doses of radioiodinated MIBG.

Continuous-wave broadly tunable Cr2+:ZnSe laser

We report room-temperature operation of an all-solid-state broadly tunable continuous-wave Cr(2+):ZnSe laser. Output power of 250 mW, an absorbed power slope efficiency of 63%, and continuous tunability from 2138 to 2760 nm are demonstrated.

Helicobacter pylori induces apoptosis in mucosal lymphocytes in patients with gastritis

BACKGROUND

Previous studies suggest that Helicobacter pylori (H. pylori) induces apoptosis and compensatory hyperproliferation in gastric epithelial cells possibly explaining the carcinogenic capacity of the bacteria. The aim of this study was to measure the effect of H. pylori on apoptosis of gastric lymphoid cells in view of the development of gastric lymphoma.

METHODS

16 H. pylori-positive and 19 H. pylori-negative individuals were enrolled. Single cell suspensions were prepared from antral biopsies and apoptosis was measured by staining with the TUNEL-assay and the fluorochrome Hoechst 33342. Lymphocyte subsets were simultaneously identified by immunocytochemistry.

RESULTS

The apoptotic index of all gastric mucosal cells was significantly higher in H. pylori-positive mucosa compared to negative controls. Additionally, H. pylori-infected patients showed a significant increase in apoptosis of mucosal B-lymphocytes. Apoptosis of T cells and plasma cells was unaffected by H. pylori.

CONCLUSION

H. pylori induces apoptosis in mucosal B cells which might be important in the development of gastritis and possibly B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT).

Species differences in the glutathione transferase GSTT1-1 activity towards the model substrates methyl chloride and dichloromethane in liver and kidney

Glutathione transferase (GST) GSTT1-1 is involved in the biotransformation of several chemicals widely used in industry, such as butadiene and dichloro methane DCM. The polymorphic hGSTT1-1 may well play a role in the development of kidney tumours after high and long-term occupational exposure against trichloroethylene. Although several studies have investigated the association of this polymorphism with malignant diseases little is known about its enzyme activity in potential extrahepatic target tissues. The known theta-specific substrates methyl chloride (MC) dichloromethane and 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) were used to assay GSTT1-1 activity in liver and kidney of rats, mice, hamsters and humans differentiating the three phenotypes (non-conjugators, low conjugators, high conjugators) seen in humans. In addition GSTT1-1 activity towards MC and DCM was determined in human erythrocytes. No GSTT1-1 activity was found in any tissue of non-conjugators (NC). In all organs high conjugators (HC) showed twofold higher activity towards MC and DCM than low conjugators (LC). The activity in human samples towards EPNP was too close to the detection limit to differentiate between the three conjugator phenotypes. GSTT1-1 activity towards MC was two to seven-times higher in liver cytosol than in kidney cytosol. The relation for MC between species was identical in both organs: mouse > HC > rat > LC > hamster > NC. In rats, mice and hamsters GSTT1-1 activity in liver cytosol towards DCM was also two to seven-times higher than in the kidney cytosol. In humans this activity was twice as high in kidney cytosol than in liver cytosol. The relation between species was mouse > rat > HC > LC > hamster > NC for liver, but mouse > HC > LC/rat > hamster/NC for kidney cytosol. The importance to heed the specific environment at potential target sites in risk assessment is emphasized by these results.

[Amiodarone and thyroid function: clinical implications]

World-wide, the incidence of amiodarone-induced thyroid dysfunction is estimated to be between 2% and 24%. More than 50% of patients who receive long-term amiodarone have abnormal results on thyroid function tests. However, most of these patients are euthyroid. In a euthyroid amiodarone-treated patient, an increase in serum thyroxine levels (total and free) and in serum reverse T3 levels and a decrease in serum T3 levels (total and free), are observed. TSH levels are within the normal range with chronic treatment (more than 3 months). The aim of this study was to identify the frequency of amiodarone prescription by cardiologists, to learn about their clinical practice in screening for thyroid dysfunction, and to formulate guidelines for clinical investigation of thyroid function before and during amiodarone treatment. A questionnaire was sent to 27 cardiologists in private practice in the Geneva area and to 12 cardiologists in Geneva University Hospital (19 and 7 questionnaires returned respectively). Cardiologists in private practice prescribe amiodarone quite frequently (once to twice per month and more). Clinical investigation prior to treatment involves history (95%), clinical examination (63%) or thyroid function tests (37% routinely, 16% where there is clinical suspicion of thyroid dysfunction). Thyroid function is investigated by determination of TSH (100%), free T4 (68%), free T3 (50%), total T3 (32%) or total T4 (26%). Antithyroid antibodies are measured only by 10% of the cardiologists in private practice. Cardiologists would restrict amiodarone prescription in cases of clinical hyperthyroidism (90%), clinical hypothyroidism (74%), in the presence of goitre in a hyper- or hypothyroid patient (79 and 63% respectively), and if antithyroid antibodies were positive (32%). During amiodarone treatment 84% of cardiologists in private practice repeat thyroid function tests occasionally and 16% only in the presence of clinical signs. Hypothyroidism is a reason for withdrawing amiodarone treatment for 58% of the cardiologists and 37% would prescribe substitution. Hyperthyroidism is a reason for immediately suspending treatment for 90% of the cardiologists, only 5% would continue and 16% would prescribe antithyroid drugs. In conclusion, there is considerable divergence of opinion among cardiologists concerning investigation and interpretation of thyroid function before and during amiodarone treatment. Simple and practicable guidelines are needed.

An internet-accessible database of mouse developmental anatomy based on a systematic nomenclature

This paper reports an internet-accessible database of mouse developmental anatomy (DMDA) that currently holds a hierarchy of the names and synonyms of the tissues in the first 22 Theiler stages of development (E1-E13.5), together with other appropriate information. The purposes of the database are to provide, first, a nomenclature for analyzing normal and mutant mouse anatomy, and second a language for inputting, storing and querying gene-expression and other spatially organized data. DMDA currently contains some 6900 named and staged tissues (e.g. 360 and 1161 tissues in Theiler stage (TS) 14 (E9) and TS22 (E13.5) embryos). DMDA will be extended to include further lineage and other data when it becomes available. The database can be interactively accessed over the internet using either a Java or a non-Java WWW browser at http://genex.hgu.mrc.ac.uk/.

Molecular and cellular basis of radiation fibrosis

PURPOSE

Recent data from the literature and the experimental work of the authors clearly indicate that TGF-beta1 is a key modulator of cellular events, for example, induction of terminal differentiation, resulting in radiation-induced fibrosis. Therefore, the present study analysed which cellular processes induced by exogenously added TGF-beta could be responsible for the induction, development and manifestation of the fibrotic phenotype in culture.

MATERIALS AND METHODS

Rat lung fibroblast cultures (passage 1) were used. As a function of treatment with TGF-beta and/or anti-TGF-beta-antibody, the clonogenic activity and differentiation pattern were analysed by colony-formation assays.

RESULTS

It could be demonstrated that treatment of rat lung progenitor fibroblasts with TGF-beta1 resulted in a pronounced shift in the differentiation pattern, i.e. induction of post-mitotic fibrocytes. This TGF-beta1-dependent terminal differentiation could be abolished by simultaneous treatment with a neutralizing antibody directed against TGF-beta1.

CONCLUSIONS

The data presented indicate that TGF-beta1 is one major candidate mediating the accelerated terminal differentiation of progenitor fibroblasts to post-mitotic functional fibrocytes, which results in the fibrotic phenotype of this cell system.