Water-soluble, core-modified porphyrins as novel, longer-wavelength-absorbing sensitizers for photodynamic therapy

Water-soluble, core-modified 5,10,15, 20-tetrakis(4-sulfonatophenyl)-21,23-dithiaporphyrin (1) and 5,10,15, 20-tetrakis(4-sulfonatophenyl)-21,23-diselenaporphyrin (2) were prepared as the tetrasodium salts by the sulfonation of 5,10,15, 20-tetraphenyl-21,23-dithiaporphyrin (3) and -21, 23-diselenaporphyrin (4), respectively, with sulfuric acid. Compounds 3 and 4 were prepared by the condensation of pyrrole with either 2,5-bis(phenylhydroxymethyl)thiophene (5) or 2, 5-bis(phenylhydroxymethyl)selenophene (6) in propionic acid. The addition of benzaldehyde to 2,5-dilithiothiophene or 2, 5-dilithioselenophene gives 5 or 6, respectively, as a nearly equimolar mixture of meso- and d,l-diastereomers. Careful crystallization of 5 gives a single diastereomer by removing the crystalline product from the equilibrating mixture of diastereomers in solution. Photodynamic therapy (PDT) with 1 has an LD(50) of less than 25 microg/mL against Colo-26 cells in culture and exhibits a lethal dose for 90% or more at concentrations greater than 50 microg/mL. In contrast, PDT with 5,10,15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS(4)) requires concentrations of greater than 100 microg/mL to achieve LD(50). Neither 1 nor TPPS(4) shows significant photoactivity against the murine T-cell line, MOLT-4, above the dark toxicity. Sensitizer 1 shows no toxicity or side effects in BALB/c mice observed for 30 days following a single intravenous injection of 10 mg (9.1 micromol)/kg. Distribution studies show that sensitizer 1 accumulates in the tumors of BALB/c mice bearing Colo-26 or EMT-6 tumors with sensitizer concentration roughly doubling as the dosage of 1 increased from 5 to 10 mg/kg. In vivo studies show that PDT with sensitizer 1 at both 3.25 and 10 mg/kg with 135 J cm(-2) of 694-nm light is effective against Colo-26 tumors in BALB/c mice.

Synthesis and evaluation of chalcogenopyrylium dyes as potential sensitizers for the photodynamic therapy of cancer

A series of thiopyrylium (2), selenopyrylium (3), and telluropyrylium dyes (4) was prepared via the addition of Grignard reagents to either 2, 6-di(4-dimethylamino)phenylchalcogenopyran-4-ones (5a) or 2-[4-(dimethylamino)phenyl]-6-phenylchalcogenopyran-4-ones (5b) followed by elimination and ion exchange to give the chloride salts. The absorption spectra and quantum yields for singlet oxygen generation of these dyes suggested that the dyes would have utility as sensitizers for PDT. Selenopyrylium dyes 3a and 3d with quantum yields for singlet oxygen generation of 0.040 and 0.045, respectively, were phototoxic to Colo-26 cells in culture. The toxicity of the dyes 2-4 was evaluated in clonogenic assays of human carcinoma cell lines. Importantly, the presence of a sulfur, selenium, or tellurium heteroatom in the molecules had no predictable impact on the toxicity of any particular dye set. Substituents at the 2-, 4-, and 6-positions of the dye had a much greater impact on cytotoxicity. The IC(50) values determined in the clonogenic assays did not correlate with chemical properties in the dye molecules such as reduction potential or lipophilicity. Initial in vivo toxicity studies showed no toxicity for these dyes at dosages between 7.2 and 38 micromol/kg in BALB/c mice.

Recombinant human osteogenic protein 1 is a potent stimulator of the synthesis of cartilage proteoglycans and collagens by human articular chondrocytes

OBJECTIVE

To study the effects of recombinant human osteogenic protein-1 (rHuOP-1; bone morphogenetic protein-7) on proteoglycan and collagen synthesis by human articular chondrocytes.

METHODS

Articular chondrocytes from fetal, adolescent, and adult human donors were cultured in alginate beads for 4 days in a mixture of Ham's F-12, Dulbecco's modified Eagle's medium, 10% fetal bovine serum (FBS), then for an additional 3-10 days in the presence and absence of rHuOP-1, with and without FBS. Chondrocyte synthetic activity was measured as the amount of incorporation of 35S-sulfate into proteoglycans and 3H-proline into hydroxyproline. Sieve chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis were performed to identify specific proteoglycans and collagens.

RESULTS

Recombinant human OP-1 markedly stimulated the synthesis of proteoglycans (mostly aggrecan) and collagens (predominantly type II) by all chondrocyte preparations. This did not require the presence of FBS and was associated with continued expression of the chondrocyte phenotype.

CONCLUSION

Recombinant human OP-1 is a more potent stimulator of the synthesis of cartilage-specific molecules by human articular chondrocytes than are other factors tested for comparison, including TGF beta 1 and activin A.

Doxycycline inhibits type X collagen synthesis in avian hypertrophic chondrocyte cultures

Doxycycline, a member of the tetracycline family, has been shown to reduce a type X collagen epitope as detected by immunohistochemistry with a monoclonal antibody in an avian explant culture system (). It was also shown to decrease collagenase and gelatinase activities and thus matrix degradation. This study investigates the effect of doxycycline on type X collagen synthesis in monolayer cultures of hypertrophic chondrocytes. Protein synthesis was evaluated by radioisotopic labeling during doxycycline, tetracycline, or minocycline treatment. Radiolabeled proteins were analyzed by gel electrophoresis, and total collagen was quantitated by hydroxyproline analysis. Additionally, the synthesis of type X collagen was measured by immunoprecipitation. Doxycycline was found to inhibit type X production more effectively than either of the other tetracyclines at comparable dose levels. Furthermore, type X collagen was inhibited more than other collagens, non-collagenous proteins and proteoglycans, with maximal inhibition at 80 microg/ml and an IC50 of 7 microg/ml. This inhibition by doxycycline was specific for type X collagen at 10 microg/ml, and the pattern was distinct from cycloheximide, a recognized inhibitor of protein translation. This suppression of type X collagen could not be overcome by excess extracellular calcium, conditions that have been demonstrated to induce synthesis of this protein (2).

Studies Directed Towards the Total Synthesis of Anticapsin and Related Compounds. IV. Competitive Reaction of Amino and Carboxy Substituents in the Halohydrination of 2-Aminobicyclo[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives

Bromohydrination of benzyl (1RS,2SR,4SR)-2-benzyloxycarbonylamino-1-trimethylsilyloxy-bicyclo[2.2.2]oct-5-ene-2-carboxylate (6a) and the (1RS,2RS,4SR)- diastereomer (6b) with N- bromoacetamide in aqueous dioxan has been investigated. These reactions are highly regio-and stereo-selective and give the corresponding bromohydrins (9a) and (9b), but in moderate to low yield. These bromohydrins have the necessary stereochemistry for conversion into anticapsin. The other products from the reaction are tricyclic compounds formed by capture of the anti- bromonium cation intermediates or resultant bromohydrins by interaction with the proximal protected carboxy and amino groups within the molecules. Thus the carbolactone (11) is formed from the endo -adduct (6a), and the carbonimidic acid derivative (12) and the cyclic urethane (13) are formed from the exo-adduct (6b). Cleavage of the trimethylsilyl group from the tricyclic compound (12) gives benzyl (1RS,2RS,3RS,7RS,8RS)-5-benzyloxy-2-bromo-8-hydroxy-4-oxa-6-azatricyclo[5.3.1.03,8]undec-5-ene-7-carboxylate(14), the structure of which was determined by X-ray diffraction methods and refined to a residual of 0.035 for 1549 independent observed reflections. The crystals of (14) are monoclinic, P21/c, a 12.954(3), b 6.197(3), c 26.784(7) Ǻ, β 95.33(2)°, Z 4. Reactions attempting to generate iodohydrins from the alkenes (6) were also highly regioselective and gave detrimethylsilylated iodo analogues of (11) and (13).

Systemic lupus erythematosus and the obstetrical patient--implications for the anaesthetist

Systemic lupus erythematosus (SLE) is a multisystem, chronic inflammatory disease characterized by autoantibody production. The disease is most frequently found in women of childbearing age and therefore may co-exist with pregnancy. The clinical manifestations of the disease are variable and depend on the severity of damage to organ systems such as musculoskeletal, renal, haematological, neurological, cardiac, and respiratory. Many patients require drugs such as aspirin or prednisone. The pregnant patient may experience exacerbations of the disease, neonatal loss, and obstetrical complications such as pre-eclampsia. Patients with the Lupus Anticoagulant are at risk for an abnormal perinatal course. The anaesthetic management will depend on the patient's clinical status and the well-being of the fetus. The patient should be examined to determine the extent of end organ damage, current medications, and the health of the fetus. Laboratory investigations such as a coagulation screen and tests of renal function should be performed before anaesthetic intervention if time permits. A multidisciplinary approach to care of the patient and resources to manage complications are essential to optimize the outcome for both mother and newborn.

Alprazolam in the treatment of panic disorders

An open clinical trial of alprazolam therapy of patients with panic disorder or agoraphobia with panic attacks was undertaken to clarify certain issues not resolved by previous studies. These included the proportion of patients who significantly improve with alprazolam; the relative time courses for improvement in panic attacks, anticipatory anxiety, and phobic avoidance; whether successful alprazolam treatment alters vulnerability to panic with sodium lactate infusion; and what factors predict response to alprazolam in panic patients. Thirty patients meeting DSM-III criteria for panic disorder or agoraphobia with panic attacks completed a 12-week open clinical trial, and 22 were considered responders. In responders, panic attacks showed rapid improvement, whereas improvement of anticipatory anxiety and phobic avoidance was more variable. Successful alprazolam therapy appeared to block lactate vulnerability. High pretreatment Hamilton Anxiety Scale scores were associated with poor treatment response. The data suggest that alprazolam is an effective treatment for panic disorder and agoraphobia with panic attacks, and acts by directly blocking panic attacks.