Qualitative and quantitative determination of fluoroacetic acid in Arrabidea bilabiata and Palicourea marcgravii by 19F-NMR spectroscopy

Qualitative and quantitative examination of Arrabidea bilabiata and Palicourea marcgravii by 19F-NMR spectroscopy has shown the presence of fluoroacetic acid. By acid-base enrichment it is possible to detect amounts of fluoroacetic acid which otherwise are below detection rate. The detection limit (without enrichment) is estimated to be about 4 micrograms/g. Disturbing metal ions of higher oxidation states are also removed by this way. Arrabidea bilabiata contains 64.1 micrograms/g (seeds) and 3.0 micrograms/g (leaves), and Palicourea marcgravii contains 5.4 micrograms/g (leaves).

Isolation: analysis and properties of three bradykinin-potentiating peptides (BPP-II, BPP-III, and BPP-V) from Bothrops neuwiedi venom

In the course of systematic investigations on low-molecular-weight compounds from the venom of Crotalidae and Viperidae, we have isolated and characterized at least three bradykinin-potentiating peptides (BPP-II, BPP-III, and BPP-V) from Bothrops neuwiedi venom by gel filtration on Sephadex G-25 M, Sephadex G-10 followed by HPLC. The peptides showed bradykinin-potentiating action on isolated guinea-pig ileum, for which the BPP-V was more active than of BPP-II, and BPP-III, rat arterial blood pressure, and a relevant angiotensin-converting enzyme (ACE) competitive inhibiting activity. The kinetic studies showed a Ki of the order of 9.7 x 10(-3) microM to BPP-II, 7 x 10(-3) microM to BPP-III, and 3.3 x 10(-3) microM to BPP-V. The amino acid sequence of the BPP-III has been determined to be pGlu-Gly-Gly-Trp-Pro-Arg-Pro-Gly-Pro-Glu-Ile-Pro-Pro, and the amino acid compositions of the BPP-II and BPP-V by amino acid analysis were 2Glu-2Gly-1Arg-4Pro-1Ile and 2Glu-2Gly-1Ser-3Pro-2Val-1Ile, with molecular weight of 1372, 1046, and 1078, respectively.

A new bradykinin-potentiating peptide (peptide P) isolated from the venom of Bothrops jararacussu (jararacuçu tapete, urutu dourado)

Several bradykinin potentiators were identified in the venom of Bothrops jararacussu by chromatographic techniques and biological assays. One of them which was isolated inhibited the angiotensin-converting enzyme in vitro and potentiated the bradykinin-induced lowering of the arterial pressure in the rat.

Cutaneous Metastases: A Review and Diagnostic Approach to Tumors of Unknown Origin

CONTEXT.—

Cutaneous metastases from a distant malignancy are a diagnostic challenge for pathologists. Secondary involvement of the skin by a metastatic process portends a much worse clinical prognosis than any primary cutaneous malignant mimickers. Immunohistochemical staining methods continue to evolve and are of paramount importance in diagnosis.

OBJECTIVE.—

To review the clinical, histopathologic, and immunohistochemical staining patterns for commonly encountered entities and discuss potential pitfalls in diagnosis. A practical guide useful in approaching cutaneous metastases of unknown primary is outlined.

DATA SOURCES.—

An extensive search and review of literature in PubMed was performed, processed, and condensed.

CONCLUSIONS.—

Cutaneous metastases have broad histopathologic patterns. They are nearly always dermal based, with an overall foreign appearance. They can be single papules/nodules or multiple in number, mimicking an inflammatory or infectious process. Ultimately, immunohistochemistry remains an essential diagnostic tool, and clinical correlation is paramount in the workup of these entities.

Targeting of CD38 by the Tumor Suppressor miR-26a Serves as a Novel Potential Therapeutic Agent in Multiple Myeloma

Multiple myeloma is an incurable refractory hematologic malignancy arising from plasma cells in the bone marrow. Here we investigated miR-26a function in multiple myeloma and tested single-wall carbon nanotube delivery of miR-26a in vitro and in vivo. miR-26a was downregulated in patients with multiple myeloma cells compared with plasma cells from healthy donors. miR-26a overexpression inhibited proliferation and migration and induced apoptosis in multiple myeloma cell lines. To identify the targets of miR-26a, RPMI8226-V-miR-26-GFP and RPMI8226-V-GFP cells were cultured using stable isotope labeling by amino acids in cell culture (SILAC) medium, followed by mass spectrometry analysis. In multiple myeloma cells overexpressing miR-26a, CD38 protein was downregulated and subsequently confirmed to be a direct target of miR-26a. Depletion of CD38 in multiple myeloma cells duplicated the multiple myeloma inhibition observed with exogenous expression of miR-26a, whereas restoration of CD38 overcame the inhibition of miR-26a in multiple myeloma cells. In a human multiple myeloma xenograft mouse model, overexpression of miR-26a inhibited CD38 expression, provoked cell apoptosis, and inhibited cell proliferation. Daratumumab is the first CD38 antibody drug for monotherapy and combination therapy for patients with multiple myeloma, but eventually resistance develops. In multiple myeloma cells, CD38 remained at low level during daratumumab treatment, but a high-quality response is sustained. In daratumumab-resistant multiple myeloma cells, CD38 expression was completely restored but failed to correlate with daratumumab-induced cell death. Therefore, a therapeutic strategy to confer selection pressure to maintain low CD38 expression in multiple myeloma cells may have clinical benefit. SIGNIFICANCE: These results highlight the tumor suppressor function of miR-26a via its targeting of CD38 and suggest the therapeutic potential of miR-26a in patients with multiple myeloma.

Identification of a new metabolite of macrolide immunosuppressant, like rapamycin and SDZ RAD, using high performance liquid chromatography and electrospray tandem mass spectrometry

Previously unknown metabolites from the two macrolide immunosuppressants rapamycin (sirolimus) and SDZ RAD [40-O-(2-hydroxyethyl)rapamycin] obtained after in vitro incubation with human liver microsomes have been purified. Structure elucidation was performed by nanoelectrospray ionization tandem mass spectrometry applying low energy collision activated dissociation. This ionization method is, as shown here, a powerful tool to determine metabolic pathways by analysis of even low abundance products. Product ion spectra of the isolated metabolites indicate a new kind of biotransformation reaction for rapamycin and SDZ RAD. The proposed metabolic pathway starts with an ester hydrolysis which leads to a ring-opened structure. A dehydration on C33-C34 and a supplementary hydrogenation at C33-C34 result in a structure similar to the ring-opened isomer with an single bond at C33-C34.

[Biological significance of animal toxins]

Animal toxins are not to be understood as substances of random occurrence; they are of great importance in ecology. The venom-secreting organs have developed in a wide variety of ways and serve either as an offensive weapon or for protection against enemies. Accordingly, we may distinguish between actively venemous and passively venemous animals. There are other animals that are toxic rather by chance and due to extraneous factors; these we may call poisonous animals. Research into animal toxins is important from both the chemical and the biological points of view. In addition to basic knowledge, we may hope for interesting phylogenetic results from such research.

Tannins occurring in the toxic Brazilian plant Thiloa glaucocarpa

Four tannins were isolated from dried leaves of Thiloa glaucocarpa, which is one of the plants causing poisoning of cattle in Brazil. These four tannins were determined from spectrometric and chemical evidence to be the ellagic C-glucosyl tannins vescalagin, castalagin, stachyurin and casuarinin. The main components, vescalagin and castalagin, are also known as constituents of oak (Quercus spp.), the toxicity of which for cattle is supposed to be due to tannins. Suggestions concerning the resemblance of the symptoms of poisoning by Thiloa glaucocarpa and by oak are supported by the presence of the constituents in both plants.

Isolation, characterization and biological properties of two kinin-like peptides (peptide-S and peptide-r) from Scaptocosa raptoria venom

Two peptides with kinin-like biological properties were isolated by chromatography on a Sephadex G-10 column followed by high-performance liquid chromatography, from the venom of the spider Scaptocosa raptoria. The isolated peptides (peptide-S and peptide-R) were shown to cause contraction on the isolated guinea-pig ileum at amounts equivalent to those shown by bradykinin. Both peptides relaxed the isolated rat duodenum, increased the capillary permeability, caused decreasing and biphasic effect of the arterial blood pressure in conscious rats and induced oedema in the rat paw. The peptides had activity and structural similarities to other peptides (kinin-like) isolated from venoms. The complete amino acid analysis gave peptide-S a structure with 36 amino acid residues and peptide-R 22 amino acid residues. The mol. wts were estimated to be in the range of 4000 and 2870, respectively.