Safety and effectiveness of direct-acting antiviral drugs in the treatment of hepatitis C in patients with inflammatory bowel disease.

BACKGROUND AND AIMS: Hepatitis C virus (HCV) management in Inflammatory Bowel Disease (IBD) is uncertain. The ECCO guidelines 2021 recommended HCV treatment but warn about the risk of IBD reactivation. We aimed to evaluate 1) the effectiveness and safety of direct-acting antivirals (DAAs) in IBD; 2) the interaction of DAAs with IBD drugs. METHODS: Multicentre study of IBD patients and HCV treated with DAAs. Variables related to liver diseases and IBD, as well as adverse events (AEs) and drug interactions, were recorded. McNemar's test was used to assess differences in the proportion of active IBD during the study period. RESULTS: We included 79 patients with IBD and HCV treated with DAAs from 25,998 IBD patients of the ENEIDA registry. Thirty-one (39.2 %) received immunomodulators/biologics. There were no significant differences in the percentage of active IBD at the beginning (n = 11, 13.9 %) or at the 12-week follow-up after DAAs (n = 15, 19 %) (p = 0.424). Sustained viral response occurred in 96.2 % (n = 76). A total of 8 (10.1 %) AEs occurred and these were unrelated to activity, type of IBD, liver fibrosis, immunosuppressants/biologics, and DAAs. CONCLUSIONS: We demonstrate a high efficacy and safety of DAAs in patients with IBD and HCV irrespective of activity and treatment of IBD.

[Preliminary results of hybrid fixation modular implant in revision knee arthroplasty]. / Resultados preliminares de la artroplastía de revisión de rodilla con implante modular de fijación híbrida.

INTRODUCTION: revision total knee arthroplasty (TKA) is a challenging procedure that requires proper alignment, restoration of bone loss, and prevention of instability. Modern revision systems offer progressive implant constriction with multiple options for offset, augmentation, and fixation stems. OBJECTIVE: to evaluate the clinical outcomes of a modular implant with hybrid fixation in revision TKA with a minimum follow-up of two years. MATERIAL AND METHODS: we retrospectively included all revision TKA surgeries performed between September 2018 and September 2019, using the same implant. Patient demographics, comorbidities, and data on bone defects were recorded. Clinical outcomes were assessed using subjective roles and Maudsley scores and the Knee Society Score (KSS). Complications during follow-up were also documented. RESULTS: a total of 23 patients were analyzed, comprising 65% females and 35% males, with a median age of 71.1 years. Bone defects following implant removal were classified as F2.T2 in 39.13% of cases, F1.T2 in 8.69%, and F1.T1 in the remaining 52.17%. There were significant improvements in the KSS score (preoperative: 53 points, postoperative: 79 points; p < 0.001). Three (13%) complications were reported, two of which were directly related to the surgery, and two patients required subsequent revision surgery. The 2-year survival rate was 91.3%. CONCLUSION: the use of a modular implant with hybrid fixation in revision TKA demonstrated a high 2-year survival rate, significant improvements in clinical scores, and a low incidence of short-term complications. These findings support the efficacy and safety of this approach, providing favorable clinical outcomes and high patient satisfaction.

INTRODUCCIÓN: la artroplastía total de rodilla (ATR) de revisión es un procedimiento desafiante que requiere alineación adecuada, restauración ósea y estabilidad. Los sistemas modernos de revisión ofrecen opciones de implantes modulares con fijación híbrida. OBJETIVO: evaluar los resultados clínicos de un implante modular de fijación híbrida con seguimiento mínimo de dos años. MATERIAL Y MÉTODOS: se incluyeron retrospectivamente cirugías de revisión de ATR realizadas entre Septiembre de 2018 y Septiembre de 2019 con el mismo implante. Se registraron datos demográficos, comorbilidades y se evaluaron los resultados clínicos utilizando puntuaciones subjetivas y la Knee Society Score (KSS). RESULTADOS: se analizaron 23 pacientes (65% mujeres, 35% hombres; edad mediana: 71.1 años). Los defectos óseos posteriores a la extracción del implante se clasificaron como F2.T2 en 39.13% de los casos, F1.T2 en 8.69%, y F1.T1 en 52.17%. Se observaron mejoras significativas en la puntuación de la KSS (preoperatoria: 53 puntos, postoperatoria: 79 puntos; p < 0.001). Se registraron tres (13%) complicaciones totales, dos relacionadas directamente con la cirugía, y dos casos requirieron una nueva cirugía de revisión. La tasa de supervivencia a los dos años fue de 91.3%. CONCLUSIÓN: el uso del implante modular con fijación híbrida en la revisión de ATR mostró una alta tasa de supervivencia a dos años, mejoras significativas en las puntuaciones clínicas y baja incidencia de complicaciones a corto plazo. Estos resultados respaldan la eficacia y seguridad de este enfoque, proporcionando resultados clínicos favorables y alta satisfacción del paciente.

Resultados preliminares de la artroplastía de revisión de rodilla con implante modular de fijación híbrida / Preliminary results of hybrid fixation modular implant in revision knee arthroplasty

Resumen: Introducción: la artroplastía total de rodilla (ATR) de revisión es un procedimiento desafiante que requiere alineación adecuada, restauración ósea y estabilidad. Los sistemas modernos de revisión ofrecen opciones de implantes modulares con fijación híbrida. Objetivo: evaluar los resultados clínicos de un implante modular de fijación híbrida con seguimiento mínimo de dos años. Material y métodos: se incluyeron retrospectivamente cirugías de revisión de ATR realizadas entre Septiembre de 2018 y Septiembre de 2019 con el mismo implante. Se registraron datos demográficos, comorbilidades y se evaluaron los resultados clínicos utilizando puntuaciones subjetivas y la Knee Society Score (KSS). Resultados: se analizaron 23 pacientes (65% mujeres, 35% hombres; edad mediana: 71.1 años). Los defectos óseos posteriores a la extracción del implante se clasificaron como F2.T2 en 39.13% de los casos, F1.T2 en 8.69%, y F1.T1 en 52.17%. Se observaron mejoras significativas en la puntuación de la KSS (preoperatoria: 53 puntos, postoperatoria: 79 puntos; p < 0.001). Se registraron tres (13%) complicaciones totales, dos relacionadas directamente con la cirugía, y dos casos requirieron una nueva cirugía de revisión. La tasa de supervivencia a los dos años fue de 91.3%. Conclusión: el uso del implante modular con fijación híbrida en la revisión de ATR mostró una alta tasa de supervivencia a dos años, mejoras significativas en las puntuaciones clínicas y baja incidencia de complicaciones a corto plazo. Estos resultados respaldan la eficacia y seguridad de este enfoque, proporcionando resultados clínicos favorables y alta satisfacción del paciente.

Abstract: Introduction: revision total knee arthroplasty (TKA) is a challenging procedure that requires proper alignment, restoration of bone loss, and prevention of instability. Modern revision systems offer progressive implant constriction with multiple options for offset, augmentation, and fixation stems. Objective: to evaluate the clinical outcomes of a modular implant with hybrid fixation in revision TKA with a minimum follow-up of two years. Material and methods: we retrospectively included all revision TKA surgeries performed between September 2018 and September 2019, using the same implant. Patient demographics, comorbidities, and data on bone defects were recorded. Clinical outcomes were assessed using subjective roles and Maudsley scores and the Knee Society Score (KSS). Complications during follow-up were also documented. Results: a total of 23 patients were analyzed, comprising 65% females and 35% males, with a median age of 71.1 years. Bone defects following implant removal were classified as F2.T2 in 39.13% of cases, F1.T2 in 8.69%, and F1.T1 in the remaining 52.17%. There were significant improvements in the KSS score (preoperative: 53 points, postoperative: 79 points; p < 0.001). Three (13%) complications were reported, two of which were directly related to the surgery, and two patients required subsequent revision surgery. The 2-year survival rate was 91.3%. Conclusion: the use of a modular implant with hybrid fixation in revision TKA demonstrated a high 2-year survival rate, significant improvements in clinical scores, and a low incidence of short-term complications. These findings support the efficacy and safety of this approach, providing favorable clinical outcomes and high patient satisfaction.

[Bisphosphonate-related osteonecrosis of the jaws. An update]. / Osteonecrosis de los maxilares por bisfosfonatos. Actualización y puesta al día.

Bisphosphonates are widely used drugs, primarily for osteoporosis and also in oncology. A drug-induced side effect or complication, which only recently came to light in 2003, is osteonecrosis of the jaw. This study reviews the chemical characteristics of the various bisphosphonates, their possible mechanism of action, relative potency, the commercial products available on the spanish pharmaceutical market and the indications for bisphosphonate treatment. The study also considers osteonecrosis of the jaw with regard to its onset, concept, clinical stages, why this pathology affects the jaws, its risk factors, incidence, the attitude to be adopted by dentists with patients taking bisphosphonates, a quick review of the treatment and the possible prediction of osteonecrosis.

[Causes of exodontia in the Navarra Health Service-Osasunbidea: epidemiological study]. / Causas de exodoncia en el Servicio Navarro de Salud-Osasunbidea: estudio epidemiológico.

The aim of this paper is to show the causes of the dental extractions in the Navarra Health Service-Osasunbidea. For 6 months all the dental extractions carried out in the clinics of the Navarra Health Service in Pamplona were registered. Data was registered for each extraction carried out. A note was made of the age and sex of the patient, the tooth extracted and the cause of the exodontia. The causes considered were: periodontia, caries, mixed causes, orthodontia, fracture and others. 4,259 extractions were carried out; 62.1% were on men and 37.9% on women (significatively different from the general population, p < 0.0001). The average age was 53.14 years (SD = 16.77 years, 95% CI: 52.62 to 53.66 years). 49.9% of extractions were due to caries, 33.7% for periodontal reasons, 3.6% for mixed causes, 1.6% for orthodontia, 0.7% because of fracture, and 10.4% for other causes. There were statistically significant differences in the distribution by sexes of the exodontias due to periodontia (p = 0.0001), orthodontia (p < 0.0001) and other causes ((p = 0.0009). The average age of the exodontias due to periodontia, accumulated in the front teeth, was greater than that for caries (p < 0.0001), accumulated in the back teeth. The average age of the exodontias due to orthodontia was 20.16 years (p < 0.0001 with all of the other causes).

Identification of a novel member of the T1R family of putative taste receptors.

In the gustatory system, the recognition of sugars, amino acids and bitter-tasting compounds is the function of specialized G protein-coupled receptors. Recently, two members of novel subfamily of G protein-coupled receptors were proposed to function as taste receptors based on their specific expression in taste receptor cells. Here, we report the identification of a third member, T1R3, of this family of receptors. T1R3 maps near the telomere of mouse chromosome 4 rendering it a candidate for the Sac locus, a primary determinant of sweet preference in mice. Consistent with its candidacy for the Sac locus, T1R3 displays taste receptor cell-specific expression. In addition, taster and non-taster strains of mouse harbor different alleles of T1R3.

An aspartate residue at the extracellular boundary of TMII and an arginine residue in TMVII of the gastrin-releasing peptide receptor interact to facilitate heterotrimeric G protein coupling.

The mammalian bombesin receptor subfamily of G protein-coupled receptors currently consists of the gastrin-releasing peptide receptor (GRP-R), neuromedin B receptor, and bombesin receptor subtype 3. All three receptors contain a conserved aspartate residue (D98) at the extracellular boundary of transmembrane domain II and a conserved arginine residue (R309) near the extracellular boundary of transmembrane domain VII. To evaluate the functional role of these residues, site-directed GRP-R mutants were expressed in fibroblasts and assayed for their ability to both bind agonist and catalyze exchange of guanine nucleotides. Alanine substitution at GRP-R position 98 or 309 reduced agonist binding affinity by 24- and 56-fold, respectively, compared to wild-type GRP-R. Single swap GRP-R mutations either resulted in no receptor expression in the membrane (D98R) or the protein was not able to bind agonist (R309D). In contrast, the double swap mutation (D98R/R309D) had high-affinity agonist binding, reduced from wild-type GRP-R by only 6-fold. In situ reconstitution of urea-extracted membranes expressing either wild-type or mutant (D98A or R309A) GRP-R with G(q) indicated that alanine substitution greatly reduced G protein catalytic exchange compared to wild-type GRP-R. The D98R/R309D GRP-R had both a higher intrinsic basal activity and a higher overall catalytic exchange activity compared to wild-type; however, the wild-type GRP-R produced a larger agonist-stimulated response relative to the double swap mutant. Taken together, these data show that GRP-R residues D98 and R309 are critical for efficient coupling of GRP-R to G(q). Furthermore, our findings are consistent with a salt bridge interaction between these two polar and oppositely charged amino acids that maintains the proper receptor conformation necessary to interact with G proteins.

The bombesin receptor subtypes have distinct G protein specificities.

We used an in situ reconstitution assay to examine the receptor coupling to purified G protein alpha subunits by the bombesin receptor family, including gastrin-releasing peptide receptor (GRP-R), neuromedin B receptor (NMB-R), and bombesin receptor subtype 3 (BRS-3). Cells expressing GRP-R or NMB-R catalyzed the activation of squid retinal Galphaq and mouse Galphaq but not bovine retinal Galphat or bovine brain Galphai/o. The GRP-R- and NMB-R-catalyzed activations of Galphaq were dependent upon and enhanced by different betagamma dimers in the same rank order as follows: bovine brain betagamma > beta1gamma2 >> beta1gamma1. Despite these qualitative similarities, GRP-R and NMB-R had distinct kinetic properties in receptor-G protein coupling. GRP-R had higher affinities for bovine brain betagamma, beta1gamma1, and beta1gamma2 and squid retinal Galphaq. In addition, GRP-R showed higher catalytic activity on squid Galphaq. Like GRP-R and NMB-R, BRS-3 did not catalyze GTPgammaS binding to Galphai/o or Galphat. However, BRS-3 showed little, if any, coupling with squid Galphaq but clearly activated mouse Galphaq. GRP-R and NMB-R catalyzed GTPgammaS binding to both squid and mouse Galphaq, with GRP-R activating squid Galphaq more effectively, and NMB-R also showed slight preference for squid Galphaq. These studies reveal that the structurally similar bombesin receptor subtypes, in particular BRS-3, possess distinct coupling preferences among members of the Galphaq family.

Four amino acid residues are critical for high affinity binding of neuromedin B to the neuromedin B receptor.

Three mammalian bombesin receptor subtypes have been characterized: the gastrin-releasing peptide receptor (GRP-R), the neuromedin B receptor (NMB-R), and bombesin receptor subtype 3 (BRS-3). In a previous report we identified four amino acids that are critical for high affinity binding of bombesin and gastrin-releasing peptide (GRP) to the GRP-R. These four amino acids are conserved in all species variants of the GRP-R and NMB-R which bind bombesin with high affinity, but they are diverged in BRS-3, the bombesin receptor subtype that binds bombesin with much lower affinity. Substituting these four divergent amino acids in BRS-3 for the conserved amino acids in either GRP-R or NMB-R increased the affinity of the mutated BRS-3 (4DeltaBRS-3) for bombesin compared with wild-type BRS-3. We hypothesized that the same four amino acids might be critical for high affinity NMB binding to the NMB-R. In this study we confirm this hypothesis by showing that the affinity of NMB is increased in a mutant BRS-3 receptor (4DeltaBRS-3) that contains these four substitutions resulting in an affinity that is close to the affinity of wild-type NMB-R for NMB. In contrast, these four amino acid substitutions in BRS-3 did not result in the formation of a high affinity binding site for the recently described non-peptide NMB-R antagonist PD168368.

Ability of various bombesin receptor agonists and antagonists to alter intracellular signaling of the human orphan receptor BRS-3.

Bombesin (Bn) receptor subtype 3 (BRS-3) is an orphan receptor that is a predicted member of the heptahelical G-protein receptor family and so named because it shares a 50% amino acid homology with receptors for the mammalian bombesin-like peptides neuromedin B (NMB) and gastrin-releasing peptide. In a recent targeted disruption study, in which BRS-3-deficient mice were generated, the mice developed obesity, diabetes, and hypertension. To date, BRS-3's natural ligand remains unknown, its pharmacology unclear, and cellular basis of action undetermined. Furthermore, there are few tissues or cell lines found that express sufficient levels of BRS-3 protein for study. To define the intracellular signaling properties of BRS-3, we examined the ability of [D-Phe6,beta-Ala11,Phe13, Nle14]Bn-(6-14), a newly discovered peptide with high affinity for BRS-3, and various Bn receptor agonists and antagonists to alter cellular function in hBRS-3-transfected BALB 3T3 cells and hBRS-3-transfected NCI-H1299 non-small cell lung cancer cells, which natively express very low levels of hBRS-3. This ligand stimulated a 4-9-fold increase in [3H]inositol phosphate formation in both cell lines under conditions where it caused no stimulation in untransfected cells and also stimulated an increase in [3H]IP1, [3H]IP2, and 3H]IP3. The elevation of [3H]IP was concentration-dependent, with an EC50 of 20-35 nM in both cell lines. [D-Phe6,beta-Ala11,Phe13,Nle14]Bn-(6-14) stimulated a 2-3-fold increase in [Ca2+]i, a 3-fold increase in tyrosine phosphorylation of p125(FAK) with an EC50 of 0.2-0.7 nM, but failed to either stimulate increases in cyclic AMP or inhibit forskolin-stimulated increases. None of nine naturally occurring Bn peptides or three synthetic Bn analogues reported to activate hBRS-3 did so with high affinity. No high affinity Bn receptor antagonists had high affinity for the hBRS-3 receptor, although two low affinity antagonists for gastrin-releasing peptide and NMB receptors, [D-Arg1,D-Trp7,9, Leu11]substance P and [D-Pro4,D-Trp7,9,10]substance P-(4-11), inhibited hBRS-3 receptor activation. The NMB receptor-specific antagonist D-Nal,Cys,Tyr,D-Trp,Lys,Val, Cys,Nal-NH2 inhibited hBRS-3 receptor activation in a competitive fashion (Ki = 0.5 microM). Stimulation of p125(FAK) tyrosine phosphorylation by hBRS-3 activation was not inhibited by the protein kinase C inhibitor, GF109203X, or thapsigargin, alone or in combination. These results show that hBRS-3 receptor activation increases phospholipase C activity, which causes generation of inositol phosphates and changes in [Ca2+]i and is also coupled to tyrosine kinase activation, but is not coupled to adenylate cyclase activation or inhibition. hBRS-3 receptor activation results in tyrosine phosphorylation of p125(FAK), and it is not dependent on activation of either limb of the phospholipase C cascade. Although the natural ligand is not a known bombesin-related peptide, the availability of [D-Phe6,beta-Ala11, Phe13,Nle14]Bn-(6-14), which functions as a high affinity agonist in conjunction with hBRS-3-transfected cell lines and the recognition of three classes of receptor antagonists including one with affinity of 0.5 microM, should provide important tools to assist in the identification of its natural ligand, the development of more potent selective receptor antagonists and agonists, and further exploration of the signaling properties of the hBRS-3 receptor.

Identification of a unique ligand which has high affinity for all four bombesin receptor subtypes.

Four subtypes of bombesin receptors are identified (gastrin-releasing peptide receptor, neuromedin B receptor, the orphan receptor bombesin receptor subtype 3 (BB3 or BRS-3) and bombesin receptor subtype 4 (BB4)), however, only the pharmacology of the gastrin-releasing peptide receptor has been well studied. This lack of data is due in part to the absence of a general ligand. Recently we have discovered a ligand, 125I-[D-Tyr6,betaAla11,Phe13,Nle14]bombesin-(6-1 4) that binds to BRS-3 receptors. In this study we investigate its ability to interact with all four bombesin receptor subtypes. In rat pancreatic acini containing only gastrin-releasing peptide receptor and in BB4 transfected BALB cells, this ligand and 125I-[Tyr4]bombesin, the conventional gastrin-releasing peptide receptor ligand, gave similar results for receptor number, affinity for bombesin and affinity for the unlabeled ligand. In neuromedin B receptor transfected BALB cells, this ligand and 125I-[D-Tyr0]neuromedin B, the generally used neuromedin B receptor ligand, gave similar results for receptor number, neuromedin B affinity or the unlabeled ligand affinity. Lastly, in BRS-3 transfected BALB cells, only this ligand had high affinity. For all four bombesin receptors this ligand had an affinity of 1-8 nM and was equal or greater in affinity than any other specific ligands for any receptor. The unlabeled ligand is specific for gastrin-releasing peptide receptors on rat pancreatic acini and did not inhibit binding of 125I-cholecystokinin octapeptide (125I-CCK-8), 125I-vasoactive intestinal peptide (125I-VIP) or 125I-endothelin to their receptors. The unlabeled ligand was an agonist only at the gastrin-releasing peptide receptor in rat acini and did not interact with CCK(A) receptors or muscarinic M3 acetylcholine receptors to increase [3H]inositol phosphates. These results demonstrate 125I-[D-Tyr6,betaAla11,Phe13,Nle14]bombesin-(6-1 4) is a unique ligand with high affinity for all subtypes of bombesin receptors. Because of the specificity for bombesin receptors, this ligand will be a valuable addition for such pharmacological studies as screening for bombesin receptor agonists or antagonists and, in particular, for investigating BRS-3 cell biology, a receptor for which no ligand currently exists.

Discovery of a high affinity radioligand for the human orphan receptor, bombesin receptor subtype 3, which demonstrates that it has a unique pharmacology compared with other mammalian bombesin receptors.

An orphan receptor discovered in 1993 was called bombesin receptor subtype 3 (BRS-3) because of 47-51% amino acid identity with bombesin (Bn) receptors. Its pharmacology is unknown, because no naturally occurring tissues have sufficient receptors to allow studies. We made two cell lines stably expressing the human BRS-3 (hBRS-3). hBRS-3 was overexpressed in the human non-small cell lung cancer cells, NCI-H1299, and the other was made in Balb 3T3 cells, which lack endogenous BRS-3. [D-Phe6,beta-Ala11,Phe13, Nle14]Bn-(6-14) (where Nle represents norleucine) was discovered to have high potency for stimulating inositol phosphate formation in both cell lines. [125I-D-Tyr6,beta-Ala11,Phe13, Nle14]Bn-(6-14) bound to both cell lines with high affinity. Neither Bn nor 14 other naturally occurring Bn peptides bound to hBRS-3 with a Kd <1000 nM. Twenty-six synthetic peptides that are high affinity agonists or antagonists at other bombesin receptors had an affinity >1000 nM. Guanosine 5'-(beta,gamma-imido)triphosphate inhibited binding to both cells due to a change in receptor affinity. These results demonstrate hBRS-3 has a unique pharmacology. It does not interact with high affinity with any known natural agonist or high affinity antagonist of the Bn receptor family, suggesting the natural ligand is either an undiscovered member of the Bn peptide family or an unrelated peptide. The availability of these cell lines and the hBRS-3 ligand should facilitate identification of the natural ligand for BRS-3, its pharmacology, and cell biology.

Identification of four amino acids in the gastrin-releasing peptide receptor that are required for high affinity agonist binding.

The bombesin family of G-protein-coupled receptors includes the gastrin-releasing peptide receptor (GRP-R), the neuromedin B receptor (NMB-R), bombesin receptor subtype 3 (BRS-3), and bombesin receptor subtype 4 (bb4). All species homologues of GRP-R, NMB-R, and bb4 bind bombesin with dissociation constants in the nanomolar range; by comparison, human BRS-3 binds bombesin at much lower affinity (Kd >> 1 microM). We used this difference to help identify candidate residues that were potentially critical for forming the bombesin binding pocket. We reasoned that amino acids essential for bombesin binding would be conserved among all homologues of bb4, NMB-R, and GRP-R; conversely, at least one of these amino acids would not be conserved among homologues of BRS-3. Amino acid sequence alignment revealed nine residues that fit this model. We replaced each of these amino acids in mouse GRP-R with the homologous amino acid in human BRS-3. Four substitutions resulted in a significant decrease in bombesin affinity (R288H, Q121R, P199S, and A308S). The analogous mutations in BRS-3 (R127Q, H294R, S205P, and S315A) together resulted in a receptor with a 100-fold increase in bombesin and GRP affinities relative to wild-type BRS-3. From this, we propose a preliminary map of some of the amino acids comprising the agonist binding pocket.

The gastrin-releasing peptide receptor is rapidly phosphorylated by a kinase other than protein kinase C after exposure to agonist.

Several guanine nucleotide-binding protein-coupled receptors are known to be rapidly phosphorylated after agonist exposure. In this study we show that the gastrin-releasing peptide receptor (GRP-R) is rapidly phosphorylated in response to agonist exposure. When [32P]orthophosphate-labeled cells were exposed to bombesin, the receptor was maximally phosphorylated on serine and threonine residues within 1 min. Although addition of 12-O-tetradecanoylphorbol 13-acetate also resulted in phosphorylation of the GRP-R, elimination of protein kinase C activity using the inhibitor 7-hydroxystaurosporine did not prevent bombesin-induced GRP-R phosphorylation. We conclude that a kinase other than protein kinase C is principally responsible for the rapid, agonist-induced phosphorylation of the GRP-R.

Jasplakinolide's inhibition of the growth of prostate carcinoma cells in vitro with disruption of the actin cytoskeleton.

BACKGROUND: Jasplakinolide, a cyclodepsipeptide produced by an Indo-Pacific sponge, Jaspis johnstoni, has been reported to inhibit the growth of breast cancer cells. PURPOSE: The effects of jasplakinolide on the proliferation of three human immortalized prostate carcinoma cell lines (PC-3, LNCaP, and TSU-Pr1) were studied. The growth-inhibitory effect of jasplakinolide on the PC-3 cell line was studied in detail to elucidate its mechanism of action. METHODS: Cell counts were used to study growth inhibition. A protein-based microplate assay was used to assess the time of exposure needed to cause persistent growth inhibition and to study the effects of jasplakinolide analogues. Metabolic changes were assessed by following the incorporation of radiolabeled precursors. The effects of jasplakinolide on the cytoskeleton were studied by fluorescent microscopy, using rhodamine phalloidin (RP) and antibodies to cytoskeletal components. Changes in RP binding were quantified by extracting bound fluorescent material from fixed cells and measuring the amount of fluorescence in a spectrofluorometer. RESULTS: The growth of PC-3, LNCaP, and TSU-Pr1 cells was potently inhibited by exposure to jasplakinolide for 48 hours; doses of jasplakinolide that led to 50% growth inhibition were 65 nM for PC-3 cells, 41 nM for LNCaP cells, and 170 nM for TSU-Pr1 cells. In PC-3 cells, exposure to 160 nM for 48 hours led to total growth inhibition, which persisted for several days even after drug removal. Several jasplakinolide analogues also inhibited the growth of PC-3 cells, although analogues in which the rigidity of the macrolide ring was altered were ineffective. No early changes in the synthesis of DNA, RNA, or protein or in intracellular adenosine triphosphate levels were seen in the PC-3 cells after exposure to jasplakinolide. Growth inhibition by jasplakinolide was accompanied by striking morphologic changes. Exposure for several doublings led to multinucleated cells. Further investigation of these changes in the PC-3 cells revealed a dramatic and early disruption of the actin cytoskeleton and a statistically significant decrease in RP binding. The doses of jasplakinolide, the time of exposure, and the pattern of growth inhibition by structural analogues corresponded with the changes seen in actin distribution. CONCLUSIONS: Jasplakinolide represents a novel marine natural product with potent in vitro antiproliferative activity against human prostate carcinoma cell lines, and it appears to target the actin cytoskeleton. IMPLICATIONS: Jasplakinolide is a potential candidate for further preclinical development and a lead structure for a novel class of therapeutic agents that can disrupt the actin cytoskeleton in mammalian cells.

Preliminary study of treatment of sulphuric pickling water waste from steelmaking by bio-oxidation with Thiobacillus ferrooxidans.

This report looks at the laboratory-scale recovery of iron oxides (alpha Fe2O3 type) through bio-oxidation with Thiobacillus ferrooxidans of the ferrous sulphate contained in steel industry sulphuric pickling liquors. This is done by calcining iron sulphates and iron and ammonium sulphates obtained from the crystallization of the oxidized solution. The products of the bacterial reaction and the iron oxides are then studied according to calcination temperature. The process carried out produced 50 kg of alpha Fe2O3 per m3 of waste pickling liquor at 700 degrees C with 99.8% weight iron recovery.

Dietary fish oil-induced changes in the distribution of alpha-tocopherol, retinol, and beta-carotene in plasma, red blood cells, and platelets: modulation by vitamin E.

Healthy men (ages 24-57 y) were fed a controlled basal diet supplemented with 15 g/d of placebo oil (PO) for 10 wk followed by 15 g/d of fish-oil concentrate (FO) (fortified with 15 mg all-rac-tocopherol) for 10 wk without additional alpha-tocopherol and the last 8 wk with 200 mg alpha-tocopherol/d (FO+E). Compared with PO, FO raised plasma malondialdehyde; lowered alpha-tocopherol in plasma, red blood cells, and platelets; and raised plasma and platelet beta-carotene. Supplementation with additional alpha-tocopherol (FO+E) not only restored tocopherol concentrations but also reversed the rise in beta-carotene. The response in retinol, particularly in platelets, showed an inverse relationship to beta-carotene, alpha-tocopherol exhibiting a modulating effect on these changes. From these observations it is postulated that platelets may be a significant extraintestinal site of retinol formation from beta-carotene.