Methods for the Production of Radiolabeled Bioagents for ImmunoPET.

Immunoglobulin-based positron emission tomography (ImmunoPET) is making increasingly significant contributions to the nuclear imaging toolbox. The exquisite specificity of antibodies combined with the high-resolution imaging of PET enables clinicians and researchers to localize diseases, especially cancer, with a high degree of spatial certainty. This review focuses on the radiopharmaceutical preparation necessary to obtain those images-the work behind the scenes, which occurs even before the patient or animal is injected with the radioimmunoconjugate. The focus of this methods review will be the chelation of four radioisotopes to their most common and clinically relevant chelators.

Ruxolitinib as a treatment strategy for SARS-CoV-2 pneumonia: clinical experience in a real-world setting.

INTRODUCTION: Severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) infection is characterised by a viral phase and a severe pro-inflammatory phase. The inhibition of the JAK/STAT pathway limits the pro-inflammatory state in moderate to severe COVID-19. METHODOLOGY: We analysed the data obtained by an observational cohort of patients with SARS-CoV-2 pneumonia treated with ruxolitinib in 22 hospitals of Mexico. The applied dose was determined based on physician's criteria. The benefit of ruxolitinib was evaluated using the 8-points ordinal scale developed by the NIH in the ACTT1 trial. Duration of hospital stay, changes in pro-inflammatory laboratory values, mortality, and toxicity were also measured. RESULTS: A total of 287 patients were reported at 22 sites in Mexico from March to June 2020; 80.8% received ruxolitinib 5 mg BID and 19.16% received ruxolitinib 10 mg BID plus standard of care. At beginning of treatment, 223 patients were on oxygen support and 59 on invasive ventilation. The percentage of patients on invasive ventilation was 53% in the 10 mg and 13% in the 5 mg cohort. A statistically significant improvement measured as a reduction by 2 points on the 8-point ordinal scale was described (baseline 5.39 ± 0.93, final 3.67± 2.98, p = 0.0001). There were 74 deaths. Serious adverse events were presented in 6.9% of the patients. CONCLUSIONS: Ruxolitinib appears to be safe in COVID-19 patients, with clinical benefits observed in terms of decrease in the 8-point ordinal scale and pro-inflammatory state. Further studies must be done to ensure efficacy against mortality.

Primary saturation of α, ß-unsaturated carbonyl containing fatty acids does not abolish electrophilicity.

Metabolism of polyunsaturated fatty acids results in the formation of hydroxylated fatty acids that can be further oxidized by dehydrogenases, often resulting in the formation of electrophilic, α,ß-unsaturated ketone containing fatty acids. As electrophiles are associated with redox signaling, we sought to investigate the metabolism of the oxo-fatty acid products in relation to their double bond architecture. Using an untargeted liquid chromatography mass spectrometry approach, we identified mono- and di-saturated products of the arachidonic acid-derived 11-oxoeicosatetraenoic acid (11-oxoETE) and mono-saturated metabolites of 15-oxoETE and docosahexaenoic acid-derived 17-oxodocosahexaenoinc acid (17-oxoDHA) in both human A549 lung carcinoma and umbilical vein endothelial cells. Notably, mono-saturated oxo-fatty acids maintained their electrophilicity as determined by nucleophilic conjugation to glutathione while a second saturation of 11-oxoETE resulted in a loss of electrophilicity. These results would suggest that prostaglandin reductase 1 (PTGR1), known only for its reduction of the α,ß-unsaturated double bond, was not responsible for the saturation of oxo-fatty acids at alternative double bonds. Surprisingly, knockdown of PTGR1 expression by shRNA confirmed its participation in the formation of 15-oxoETE and 17-oxoDHA mono-saturated metabolites. Furthermore, overexpression of PTGR1 in A549 cells increased the rate and total amount of oxo-fatty acid saturation. These findings will further facilitate the study of electrophilic fatty acid metabolism and signaling in the context of inflammatory diseases and cancer where they have been shown to have anti-inflammatory and anti-proliferative signaling properties.

NIR Fluorescent Imaging and Photodynamic Therapy with a Novel Theranostic Phospholipid Probe for Triple-Negative Breast Cancer Cells.

New exogenous probes are needed for both imaging diagnostics and therapeutics. Here, we introduce a novel nanocomposite near-infrared (NIR) fluorescent imaging probe and test its potency as a photosensitizing agent for photodynamic therapy (PDT) against triple-negative breast cancer cells. The active component in the nanocomposite is a small molecule, pyropheophorbide a-phosphatidylethanolamine-QSY21 (Pyro-PtdEtn-QSY), which is imbedded into lipid nanoparticles for transport in the body. The probe targets abnormal choline metabolism in cancer cells; specifically, the overexpression of phosphatidylcholine-specific phospholipase C (PC-PLC) in breast, prostate, and ovarian cancers. Pyro-PtdEtn-QSY consists of a NIR fluorophore and a quencher, attached to a PtdEtn moiety. It is selectively activated by PC-PLC resulting in enhanced fluorescence in cancer cells compared to normal cells. In our in vitro investigation, four breast cancer cell lines showed higher probe activation levels than noncancerous control cells, immortalized human mammary gland cells, and normal human T cells. Moreover, the ability of this nanocomposite to function as a sensitizer in PDT experiments on MDA-MB-231 cells suggests that the probe is promising as a theranostic agent.

Development of fluorinated naphthofluoresceins for Cerenkov imaging.

In this paper, we report the synthesis and characterization of fluorinated derivatives of naphthofluorescein (NF), a fluorescent pH-sensitive probe that can be used for functional Cerenkov imaging. The compounds were prepared using electrophilic fluorination with dilute fluorine gas under acidic conditions. The fluorination of the NF molecule occurred in the ortho positions to the hydroxyl moiety, producing mono-, di-, and tri-substituted derivatives. The properties of the fluorinated naphthofluoresceins were similar to the parent compound, retaining pH sensitivity and fluorescence capability, but showed a more acidic pKa with increasing fluorination degree and a bathochromic shift in both absorbance and fluorescence. NF and its two major fluorinated derivatives were shown to attenuate Cerenkov radiation in the basic form; the greatest attenuation was observed at wavelengths coinciding with the absorption maxima. NF also showed potential as a Cerenkov Radiation Energy Transfer (CRET) probe. Fluorinated naphthofluoresceins provide a new family of molecular imaging probes for the detection of pH in tissue and organs by using a combination of PET and Cerenkov imaging.

Nonprotecting Group Synthesis of a Phospholipase C Activatable Probe with an Azo-Free Quencher.

The near-infrared fluorescent activatable smart probe Pyro-phosphatidylethanolamine (PtdEtn)-QSY was synthesized and observed to selectively fluoresce in the presence of phosphatidylcholine-specific phospholipase C (PC-PLC). PC-PLC is an important biological target as it is known to be upregulated in a variety of cancers, including triple negative breast cancer. Pyro-PtdEtn-QSY features a QSY21 quenching moiety instead of the Black Hole Quencher-3 (BHQ-3) used previously because the latter contains an azo bond, which could lead to biological instability.

Synthesis of pH indicators for Cerenkov imaging by electrophilic substitution of bromine by fluorine in an aromatic system.

Direct electrophilic fluorination using molecular fluorine gas is used in organic synthesis to create novel fluorine-containing compounds with potential beneficial activity that could not be obtained by nucleophilic substitution. In this paper, we report a novel electrophilic substitution of bromine by fluorine in an aromatic system. The mechanism of this type of fluorination was explored using the reaction between bromothymolsulfonphthalein (Bromothymol Blue) and dilute fluorine gas under acidic conditions. Substitution occurs in the bromine atoms located in the ortho-position relative to the hydroxyl group. A similar electrophilic fluorination of thymolsulfonphthalein (Thymol Blue) leads to a substitution of hydrogen atoms in the same position (ortho to hydroxyl). NMR spectroscopy was used to confirm the fluorination sites. NMR spectra of thymolsulfonphthalein and its derivatives under basic conditions can be explained by considering the absence of resonance between the two phenolic rings. Both dibromothymol blue and fluorobromothymol blue revealed intermolecular attenuate Cerenkov radiation selectively near their maximum absorbance in a pH dependent manner.

Coenzyme A thioester formation of 11- and 15-oxo-eicosatetraenoic acid.

Release of arachidonic acid (AA) by cytoplasmic phospholipase A2 (cPLA2), followed by metabolism through cyclooxygenase-2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH), results in the formation of the eicosanoids 11-oxo- and 15-oxo-eicosatetraenoic acid (oxo-ETE). Both 11-oxo- and 15-oxo-ETE have been identified in human biospecimens but their function and further metabolism is poorly described. The oxo-ETEs contain an α,ß-unsaturated ketone and a free carboxyclic acid, and thus may form Michael adducts with a nucleophile or a thioester with the free thiol of Coenzyme A (CoA). To examine the potential for eicosanoid-CoA formation, which has not previously been a metabolic route examined for this class of lipids, we applied a semi-targeted neutral loss scanning approach following arachidonic acid treatment in cell culture and detected inducible long-chain acyl-CoAs including a predominant AA-CoA peak. Interestingly, a series of AA-inducible acyl-CoAs at lower abundance but higher mass, likely corresponding to eicosanoid metabolites, was detected. Using a targeted LC-MS/MS approach we detected the formation of CoA thioesters of both 11-oxo- and 15-oxo-ETE and monitored the kinetics of their formation. Subsequently, we demonstrated that these acyl-CoA species undergo up to four double bond reductions. We confirmed the generation of 15-oxo-ETE-CoA in human platelets via LC-high resolution MS. Acyl-CoA thioesters of eicosanoids may provide a route to generate reducing equivalents, substrates for fatty acid oxidation, and substrates for acyl-transferases through cPLA2-dependent eicosanoid metabolism outside of the signaling contexts traditionally ascribed to eicosanoid metabolites.

Synthesis of F-18 labeled resazurin by direct electrophilic fluorination.

We present the synthesis and characterization of F18-labeled fluorinated derivatives of resazurin, a probe for cell viability. The compounds were prepared by direct fluorination of resazurin with diluted [F18]-F2 gas under acidic conditions. The fluorination occurs into the ortho-positions to the hydroxyl group producing various mono-, di-, and trifluorinated derivatives. The properties of the fluorinated resazurins are similar to the parent compound with the addition of fluorine leading to decreased pKa values and a bathochromic shift of the absorption maxima. The fluorinated resazurin derivatives can be used as probes for observation of cell viability in various cells, tissues and organs using a combination of positron emission tomography and direct optical imaging of Cerenkov luminescence.

Cerenkov-specific contrast agents for detection of pH in vivo.

UNLABELLED: We report the design, testing, and in vivo application of pH-sensitive contrast agents designed specifically for Cerenkov imaging. Radioisotopes used for PET emit photons via Cerenkov radiation. The multispectral emission of Cerenkov radiation allows for selective bandwidth quenching, in which a band of photons is quenched by absorption by a functional dye. Under acidic conditions, (18)F-labeled derivatives emit the full spectrum of Cerenkov light. Under basic conditions, the dyes change color and a wavelength-dependent quenching of Cerenkov emission is observed. METHODS: Mono- and di-(18)F-labeled derivatives of phenolsulfonphthalein (phenol red) and meta-cresolsulfonphthalein (cresol purple) were synthesized by electrophilic fluorination. Cerenkov emission was measured at different wavelengths as a function of pH in vitro. Intramolecular response was measured in fluorinated probes and intermolecular quenching by mixing phenolphthalein with (18)F-FDG. Monofluorocresol purple (MFCP) was tested in mice treated with acetazolamide to cause urinary alkalinization, and Cerenkov images were compared with PET images. RESULTS: Fluorinated pH indicators were produced with radiochemical yields of 4%-11% at greater than 90% purity. Selective Cerenkov quenching was observed intramolecularly with difluorophenol red or monofluorocresol purple and intermolecularly in phenolphthalein (18)F-FDG mixtures. The probes were selectively quenched in the bandwidth closest to the indicator's absorption maximum (λmax) at pHs above the indicator pKa (the negative logarithm of the acid dissociation constant). Addition of acid or base to the probes resulted in reversible switching from unquenched to quenched emission. In vivo, the bladders of acetazolamide-treated mice exhibited a wavelength-dependent quenching in Cerenkov emission, with the greatest reduction occurring near the λmax. Ratiometric imaging at 2 wavelengths showed significant decreases in Cerenkov emission at basic pH and allowed the estimation of absolute pH in vivo. CONCLUSION: We have created contrast agents that selectively quench photons emitted during Cerenkov radiation within a given bandwidth. In the presence of a functional dye, such as a pH indicator, this selective quenching allows for a functional determination of pH in vitro and in vivo. This method can be used to obtain functional information from radiolabeled probes using multimodal imaging. This approach allows for the imaging of nonfluorescent chromophores and is generalizable to any functional dye that absorbs at suitable wavelengths.

Luxación acromioclavicular experiencia en el Hospital Naval / Acromilclavicular luxation. Naval Hospital experience

Presenta un estudio estadístico retrospectivo de casos de luxación acromioclavicular G III diagnosticados y tratados quirúrgicamente en el Servicio de Traumatología y Ortopedia del Hospital Naval desde 1988 a 1996. Se revisó los expedientes de 44 pacientes que acudieron inicialmente a la emergencia por presentar trauma de hombros, pero luego de realizado el examen físico y estudio radiológico, se determinó que se trataba de luxación acromioclavicular G III de resolución quirúrgica. De las técnicas quirúrgicas utilizadas, las que menores resultados positivos dieron dueron aquellas que utilizaron implantes metálicos. La técnica de reducción abierta de luxación y fijación con doble lazada de ethibdon dio resultados más halagadores. Se utilizó una tercera técnica basada en reducción a foco cerrado y fijación con clavo de kirschner grueso, con resultados provisionales halagadores...

Ecotomografía en la apendicitis aguda / Echotomography in the acute appendicitis

Acute appendicitis is the most frequent cause of surgical abdominal emergency. In most of these patients (70 percent) the diagnosis is based on the clinic history and on the physical examination. In those cases the clinic presentation is confusing, the ultrasound with gray scale and high frequency transducers, using the graduated compression technique, has become of great help. It has been reported a sensibility of 84-96 percent with a specificity of 94-98 percent for the diagnostic method. Also lately is has been that the study with color doppler can be useful as help in the diagnosis of appendicitis, demostrating a local increase in the blood flow in the appendicular wall or in the inflammatory mass. However, color doppler by itself acquires its greater usefulness in those cases in which the appendicular size is limit

Ecotomografía escrotal / Scrotal ultrasound

La ecotomografía escrotal, es una herramienta de utilidad en el diagnóstico diferencial de las masas escrotales. Para establecer su correlación con la clínica seleccionamos 99 pacientes sometidos a este procedimiento y los cotejamos con los hallazgos de la anatomía patológica y con un adecuado seguimiento clínico. Obtuvimos una excelente correlación para las neoplasias testiculares, para la patología benigna testicular, y fue útil además en la búsqueda de testículos ectópicos. No resultó de utilidad para determinar características histológicas de los tumores, así como tampoco la recomendamos en los traumatismos testiculares

Etiología y frecuencia del síndrome ictérico en lactantes / Etiology and frequency of jaundice syndrome in infants

Con el propósito de conocer la frecuencia y las causas del síndrome ictérico en lactantes, se estudiaron 70 casos de manera retrospectiva y 3 en forma prospectiva; las edades oscilaron de 3 semanas a 2 años en ambos grupos. No hubo una diferencia notable entre las causas susceptibles de manejo médico y las que requerían tratamiento quirúrgico (46.2 y 45.2%, respectivamente); en 8 casos no se determinó la causa del síndrome. En el grupo de causas que ameritan tratamiento médico predominaron las infecciones (86%), y entre las que requerían cirugía se encontró atresia de vías biliares (54.7%) y otros padecimientos (45.3%)